485BPOS

As filed with the Securities and Exchange Commission on April 28, 2022

Securities Act Registration No. 2‑34223

Investment Company Act File No. 811‑1829

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM N-1A

REGISTRATION STATEMENT

UNDER

THE SECURITIES ACT OF 1933

Post-Effective Amendment No. 115

and

REGISTRATION STATEMENT

UNDER

THE INVESTMENT COMPANY ACT OF 1940

Amendment No. 90

COLUMBIA ACORN TRUST

71 S. Wacker Drive, Suite 2500

Chicago, IL 60606

Telephone number: 312.634.9200

Ryan C. Larrenaga c/o Columbia Management Investment Advisers, LLC 290 Congress Street Boston, MA 02210	Stephen Kusmierczak Dan Beckman Columbia Acorn Trust 71 S. Wacker Drive Suite 2500 Chicago, IL 60606	Mary C. Moynihan Perkins Coie LLP 700 13th Street, N.W., Suite 800 Washington, D.C. 20005
(Agents for service)

It is proposed that this filing will become effective:

☐ immediately upon filing pursuant to rule 485(b)

☒ on May 1, 2022 pursuant to rule 485(b)

☐ 60 days after filing pursuant to rule 485(a)(1)

☐ on                      pursuant to rule 485(a)(l)

☐ 75 days after filing pursuant to rule 485(a)(2)

☐ on                      pursuant to rule 485(a)(2).

 

Prospectus

May 1, 2022

Columbia Acorn Family of Funds

Managed by Columbia Wanger Asset Management, LLC

Columbia
  Acorn European Fund^SM

Class	Ticker Symbol
A	CAEAX
Advisor (Class Adv)	CLOFX
C	CAECX

Class	Ticker Symbol
Institutional (Class Inst)	CAEZX
Institutional 2 (Class Inst2)	CAEEX
Institutional 3 (Class Inst3)	CAEYX

As with all mutual funds, the Securities and Exchange Commission (SEC) has not approved or disapproved these securities or passed upon the adequacy of this prospectus. Any representation to the contrary is a criminal offense.

Table of Contents

Summary of the Fund	3
Investment Objective	3
Fees and Expenses of the Fund	3
Principal Investment Strategies	4
Principal Risks	5
Performance Information	9
Fund Management	10
Purchase and Sale of Fund Shares	10
Tax Information	11
Payments to Broker-Dealers and Other Financial Intermediaries	11
More Information About the Fund	12
Investment Objective	12
Principal Investment Strategies	12
Principal Risks	12
Additional Investment Strategies and Policies	18
Board of Trustees	23
Primary Service Provider Contracts	23
Other Roles and Relationships of Ameriprise Financial and its Affiliates — Certain Conflicts of Interest	25
Certain Legal Matters	26
Choosing a Share Class	28
The Funds	28
Summary of Share Class Features	28
Sales Charges and Commissions	34
Reductions/Waivers of Sales Charges	37
Distribution and Service Fees	41
Financial Intermediary Compensation	42
Buying, Selling and Exchanging Shares	44
Share Price Determination	44
Transaction Rules and Policies	45
Opening an Account and Placing Orders	49
Buying Shares	51
Selling Shares	56
Exchanging Shares	58
Distributions and Taxes	61
Distributions to Shareholders	61
Taxes	62
Financial Highlights	65
Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges	A-1

2

Columbia Acorn European Fund^SM

Summary of the Fund

Investment Objective

Columbia Acorn European Fund^SM (the Fund) seeks long-term capital appreciation.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below. You may qualify for sales charge discounts if you and members of your immediate family invest, or agree to invest in the future, at least $50,000 in certain classes of shares of eligible funds distributed by Columbia Management Investment Distributors, Inc. (the Distributor). More information is available about these and other sales charge discounts and waivers from your financial intermediary, and can be found in the Choosing a Share Class section beginning on page 28 of the Fund’s prospectus, in Appendix A to the prospectus beginning on page A-1 and in Appendix S to the Statement of Additional Information (SAI) under Sales Charge Waivers beginning on page S-1.

Shareholder Fees (fees paid directly from your investment)
	Class A	Class C	Classes Adv, Inst, Inst2 and Inst3
Maximum sales charge (load) imposed on purchases (as a % of offering price)	5.75%	None	None
Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)	1.00%(a)	1.00%(b)	None

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
	Class A	Class Adv	Class C	Class Inst	Class Inst2	Class Inst3
Management fees	1.09%	1.09%	1.09%	1.09%	1.09%	1.09%
Distribution and/or service (12b-1) fees	0.25%	0.00%	1.00%	0.00%	0.00%	0.00%
Other expenses	0.29%	0.29%	0.29%	0.29%	0.26%	0.22%
Total annual Fund operating expenses(c)	1.63%	1.38%	2.38%	1.38%	1.35%	1.31%
Fee waivers and/or expense reimbursements(d)	(0.18%)	(0.18%)	(0.18%)	(0.18%)	(0.21%)	(0.20%)
Total annual Fund operating expenses after fee waivers and/or expense reimbursements	1.45%	1.20%	2.20%	1.20%	1.14%	1.11%

(a)	This charge is imposed on certain investments of between $1 million and $50 million redeemed within 18 months after purchase, as follows: 1.00% if redeemed within 12 months after purchase, and 0.50% if redeemed more than 12, but less than 18, months after purchase, with certain limited exceptions.
(b)	This charge applies to redemptions within 12 months after purchase, with certain limited exceptions.

(c)

“Total annual Fund operating expenses” include acquired fund fees and expenses (expenses the Fund incurs indirectly through its investments in other investment companies) and may be higher than the ratio of expenses to average net assets shown in the Financial Highlights section of this prospectus because the ratio of expenses to average net assets does not include acquired fund fees and expenses.

(d)

Columbia Wanger Asset Management, LLC (the Investment Manager) has contractually agreed to waive fees and reimburse certain expenses of the Fund, through April 30, 2023, so that ordinary operating expenses (excluding transaction costs and certain other investment-related expenses, interest and fees on borrowings and expenses associated with the Fund’s investment in other investment companies, if any) do not exceed the annual rates of 1.45% for Class A shares, 1.20% for Class Adv shares, 2.20% for Class C shares, 1.20% for Class Inst shares, 1.14% for Class Inst2 shares and 1.11% for Class Inst3 shares. This arrangement may only be amended or terminated with approval from the Fund’s Board of Trustees and the Investment Manager. The fee waivers and/or expense reimbursements shown in the table also reflect the contractual agreement of the Fund’s transfer agent, Columbia Management Investment Services Corp. (the Transfer Agent), to waive a portion of its fees through April 30, 2023, such that the Fund’s transfer agency fees do not exceed the annual rates of 0.03% of the average daily net assets of Class Inst2 shares and 0.00% of the average daily net assets of Class Inst3 shares. This arrangement may be terminated at the sole discretion of the Fund’s Board of Trustees.

Prospectus 2022 3

Columbia Acorn European Fund^SM

Summary of the Fund (continued)

 Example

The following example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example illustrates the hypothetical expenses that you would incur over the time periods indicated, and assumes that:

■ you invest $10,000 in the applicable class of Fund shares for the periods indicated,

■ your investment has a 5% return each year, and

■ the Fund’s total annual operating expenses remain the same as shown in the Annual Fund Operating Expenses table above.

Since the waivers and/or reimbursements shown in the Annual Fund Operating Expenses table above expire as indicated in the preceding table, they are only reflected in the 1 year example and the first year of the other examples. Although your actual costs may be higher or lower, based on the assumptions listed above, your costs would be:

	1 year	3 years	5 years	10 years
Class A (whether or not shares are redeemed)	$714	$1,043	$1,395	$2,382
Class Adv (whether or not shares are redeemed)	$122	$419	$738	$1,642
Class C (assuming redemption of all shares at the end of the period)	$323	$725	$1,254	$2,516
Class C (assuming no redemption of shares)	$223	$725	$1,254	$2,516
Class Inst (whether or not shares are redeemed)	$122	$419	$738	$1,642
Class Inst2 (whether or not shares are redeemed)	$116	$407	$719	$1,606
Class Inst3 (whether or not shares are redeemed)	$113	$395	$699	$1,562

Portfolio Turnover

The Fund may pay transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 21% of the average value of its portfolio.

Principal Investment Strategies

Under normal circumstances, the Fund invests at least 80% of its net assets (plus any borrowing for investment purposes) in European companies. Under normal circumstances, the Fund invests at least 70% of its total assets in companies in Western European countries (for example, the United Kingdom, Germany, France and Italy), but also may invest up to 30% of its total assets in companies in emerging Central and Eastern European countries (for example, Poland, the Czech Republic, Turkey and Cyprus). For purposes of the Fund's policies, the Fund may invest in a company if (i) it is domiciled in, or the principal trading market for its securities is in, a European country, (ii) it derives 50% or more of its economic value from goods produced, sales made or services performed or has at least 50% of its assets in a European country or countries or (iii) it is a holding company that predominantly holds shares in such companies. The Fund may invest in a variety of countries, industries and sectors and does not attempt to invest a specific percentage of its assets in any given country, industry or sector.

Under normal circumstances, the Fund invests a majority of its net assets in the common stock of small- and mid-sized companies with market capitalizations generally in the range of market capitalizations in the MSCI AC Europe Small Cap Index (Net), the Fund's benchmark, (the Index) at the time of purchase (between $85.4 million and $10.6 billion as of March 31, 2022). The market capitalization range and composition of companies in the Index are subject to change. As such, the size of the companies in which the Fund invests may change. The Fund determines a company’s market capitalization at the time of investment. As long as a majority of its net assets are invested in companies within the Index, the Fund may continue to hold and make new investments in a security even if the 

4 Prospectus 2022

Columbia Acorn European Fund^SM

Summary of the Fund (continued)

company’s market capitalization grows beyond the market capitalization of the largest company within the Index or falls below the market capitalization of the smallest company within the Index. The Investment Manager from time to time emphasizes one or more sectors in selecting the Fund’s investments, including the industrials, information technology, and health care sectors. 

Columbia Wanger Asset Management, LLC, the Fund's investment adviser (the Investment Manager), believes that stocks of small- and mid-sized companies, which generally are not as well known by financial analysts as larger companies, may offer higher return potential than stocks of larger companies. 

The Fund takes advantage of the Investment Manager's research and stock-picking capabilities to initially invest in a limited number of companies (generally under 100), offering the potential to provide above-average growth over time. 

The Investment Manager typically seeks companies with: 

■ A strong business franchise that offers growth potential. 

■ Products and services in which the company has a competitive advantage. 

■ A stock price the Investment Manager believes is reasonable relative to the assets and earning power of the company. 

The Investment Manager may sell a portfolio holding if the security reaches the Investment Manager's price target, if the company has a deterioration of fundamentals, such as failing to meet key operating benchmarks, or if the Investment Manager believes other securities are more attractive. The Investment Manager also may sell a portfolio holding to fund redemptions. 

Principal Risks

An investment in the Fund involves risks, including those described below, among others. There is no assurance that the Fund will achieve its investment objective and you may lose money. The value of the Fund’s holdings may decline, and the Fund’s net asset value (NAV) and share price may go down. An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Active Management Risk. The Investment Manager’s active management of the Fund could cause the Fund to underperform its benchmark index and/or other funds with similar investment objectives and/or strategies.

Market Risk. The Fund may incur losses due to declines in the value of one or more securities in which it invests. These declines may be due to factors affecting a particular issuer, or the result of, among other things, political, regulatory, market, economic or social developments affecting the relevant market(s) more generally. In addition, turbulence in financial markets and reduced liquidity in equity, credit and/or fixed income markets may negatively affect many issuers, which could adversely affect the Fund’s ability to price or value hard-to-value assets in thinly traded and closed markets and could cause significant redemptions and operational challenges. Global economies and financial markets are increasingly interconnected, and conditions and events in one country, region or financial market may adversely impact issuers in a different country, region or financial market. These risks may be magnified if certain events or developments adversely interrupt the global supply chain; in these and other circumstances, such risks might affect companies worldwide. As a result, local, regional or global events such as terrorism, war, other conflicts, natural disasters, disease/virus outbreaks and epidemics or other public health issues, recessions, depressions or other events – or the potential for such events – could have a significant negative impact on global economic and market conditions. 

The large-scale invasion of Ukraine by Russia in February 2022 has resulted in sanctions and market disruptions including declines in regional and global stock and commodity markets and significant devaluations of Russian currency. The extent and duration of the military action are impossible to predict but could be significant. Market disruption caused by the Russian military action, and any counter measures or responses thereto (including international sanctions, a downgrade in the country’s credit rating, purchasing and financing restrictions, boycotts, tariffs, changes in consumer or purchaser preferences, cyberattacks and espionage) could have severe adverse impacts on regional and/or global securities and commodities markets, including markets for oil and natural gas. 

Prospectus 2022 5

Columbia Acorn European Fund^SM

Summary of the Fund (continued)

These impacts may include reduced market liquidity, distress in credit markets, further disruption of global supply chains, increased risk of inflation, and limited access to investments in certain international markets and/or issuers. These developments and other related events could negatively impact Fund performance. 

The pandemic caused by coronavirus disease 2019 and its variants (COVID-19) has resulted in, and may continue to result in, significant global economic and societal disruption and market volatility due to disruptions in market access, resource availability, facilities operations, imposition of tariffs, export controls and supply chain disruption, among others. Such disruptions may be caused, or exacerbated by, quarantines and travel restrictions, workforce displacement and loss in human and other resources. The uncertainty surrounding the magnitude, duration, reach, costs and effects of the global pandemic, as well as actions that have been or could be taken by governmental authorities or other third parties, present unknowns that are yet to unfold. The impacts, as well as the uncertainty over impacts to come, of COVID-19 – and any other infectious illness outbreaks, epidemics and pandemics that may arise in the future – could negatively affect global economies and markets in ways that cannot necessarily be foreseen. In addition, the impact of infectious illness outbreaks and epidemics in emerging market countries may be greater due to generally less established healthcare systems, governments and financial markets. Public health crises caused by the COVID-19 outbreak may exacerbate other pre-existing political, social and economic risks in certain countries or globally. The disruptions caused by COVID-19 could prevent the Fund from executing advantageous investment decisions in a timely manner and negatively impact the Fund’s ability to achieve its investment objective. Any such events could have a significant adverse impact on the value and risk profile of the Fund. 

Liquidity and Trading Volume Risk. Due to market conditions, including uncertainty regarding the price of a security, it may be difficult for the Fund to buy or sell portfolio securities at a desirable time or price, which could result in investment losses. This risk of portfolio illiquidity is heightened with respect to small- and mid-cap securities, generally, and foreign small- and mid-cap securities in particular. The Fund may have to lower the selling price, liquidate other investments, or forego another, more appealing investment opportunity as a result of illiquidity in the markets. The Fund may also be limited in its ability to execute favorable trades in portfolio securities in response to changes in share prices and fundamentals, and may be forced to dispose of securities under disadvantageous circumstances and at a loss. As the Fund grows in size or, conversely, if it faces significant redemption pressure, these considerations take on increasing significance and may adversely impact performance. 

Small- and Mid-Cap Company Securities Risk. Investments in small- and mid-cap companies often involve greater risks than investments in larger, more established companies because small- and mid-cap companies tend to have less predictable earnings and may lack the management experience, financial resources, product diversification and competitive strengths of larger companies. Securities of small- and mid-cap companies may be less liquid and more volatile than the securities of larger companies. 

Sector Risk. At times, the Fund may have a significant portion of its assets invested in securities of companies conducting business within one or more economic sectors, including the industrials, information technology, and health care sectors. Companies in the same sector may be similarly affected by economic, regulatory, political or market events or conditions, which may make the Fund more vulnerable to unfavorable developments in that sector than funds that invest more broadly. Generally, the more broadly the Fund invests, the more it spreads risk and potentially reduces the risks of loss and volatility. 

■ Industrials Sector. The Fund is more susceptible to the particular risks that may affect companies in the industrials sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the industrials sector are subject to certain risks, including changes in supply and demand for their specific product or service and for industrial sector products in general, including decline in demand for such products due to rapid technological developments and frequent new product introduction. Performance of such companies may be affected by factors including government regulation, world events, economic conditions and risks for environmental damage and product liability claims. 

■ Information Technology Sector. The Fund is more susceptible to the particular risks that may affect companies in the information technology sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the information technology sector are subject to certain risks, including the risk that new services, 

6 Prospectus 2022

Columbia Acorn European Fund^SM

Summary of the Fund (continued)

equipment or technologies will not be accepted by consumers and businesses or will become rapidly obsolete. Performance of such companies may be affected by factors including obtaining and protecting patents (or the failure to do so) and significant competitive pressures, including aggressive pricing of their products or services, new market entrants, competition for market share and short product cycles due to an accelerated rate of technological developments. Such competitive pressures may lead to limited earnings and/or falling profit margins. As a result, the value of their securities may fall or fail to rise. In addition, many information technology sector companies have limited operating histories and prices of these companies’ securities historically have been more volatile than other securities, especially over the short term. Some companies in the information technology sector are facing increased government and regulatory scrutiny and may be subject to adverse government or regulatory action, which could negatively impact the value of their securities. 

■ Health Care Sector. The Fund is more susceptible to the particular risks that may affect companies in the health care sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the health care sector are subject to certain risks, including restrictions on government reimbursement for medical expenses, government approval of medical products and services, competitive pricing pressures, and the rising cost of medical products and services (especially for companies dependent upon a relatively limited number of products or services), among others. Performance of such companies may be affected by factors including, government regulation, obtaining and protecting patents (or the failure to do so), product liability and other similar litigation as well as product obsolescence. 

Foreign Securities Risk. Investments in or exposure to securities of foreign companies may involve heightened risks relative to investments in or exposure to securities of U.S. companies. Investing in securities of foreign companies subjects the Fund to the risks associated with an issuer’s (and any of its related companies’) country of organization and places of business operations, including risks related to political, regulatory, economic, social, diplomatic and other conditions or events (including, for example, military confrontations and actions, war, other conflicts, terrorism and disease/virus outbreaks and epidemics) occurring in the country or region, as well as risks associated with less developed custody and settlement practices. Foreign securities may be more volatile and less liquid than securities of U.S. companies, and are subject to the risks associated with potential imposition of economic and other sanctions against a particular foreign country, its nationals or industries or businesses within the country. In addition, foreign governments may impose withholding or other taxes on the Fund’s income, capital gains or proceeds from the disposition of foreign securities, which could reduce the Fund’s return on such securities. 

Operational and Settlement Risks of Foreign Securities. The Fund’s foreign securities are generally held outside the United States in the primary market for the securities in the custody of foreign sub-custodians. Some countries have limited governmental oversight and regulation, which increases the risk of corruption and fraud and the possibility of losses to the Fund. In particular, under certain circumstances, foreign securities may settle on a delayed delivery basis, meaning that the Fund may be required to make payment for securities before the Fund has actually received delivery of the securities or deliver securities prior to the receipt of payment. As a result, there is a risk that the security will not be delivered to the Fund or that payment will not be received. Losses can also result from lost, stolen or counterfeit securities; defaults by brokers and banks; failures or defects of the settlement system; or poor and improper record keeping by registrars and issuers. 

Share Blocking. In certain non-U.S. markets, an issuer’s securities are blocked from trading for a specified number of days before and, in certain instances, after a shareholder meeting. The blocking period can last up to several weeks. Share blocking may prevent the Fund from buying or selling securities during this period. As a consequence of these restrictions, the Investment Manager, on behalf of the Fund, may abstain from voting proxies in markets that require share blocking. 

Geographic Focus Risk. The Fund may be particularly susceptible to risks related to economic, political, regulatory or other events or conditions affecting issuers and countries within the specific geographic regions in which the Fund invests. The Fund’s NAV may be more volatile than the NAV of a more geographically diversified fund. 

■ Europe. The Fund is particularly susceptible to risks related to economic, political, regulatory or other events or conditions, including acts of war or other conflicts in the region, affecting issuers and countries in Europe. Countries in Europe are often closely connected and interdependent, and events in one European country can have 

Prospectus 2022 7

Columbia Acorn European Fund^SM

Summary of the Fund (continued)

an adverse impact on, and potentially spread to, other European countries. In addition, significant private and public sectors’ debt problems of a single European Union (EU) country can pose economic risks to the EU as a whole. As a result, the Fund’s NAV may be more volatile than the NAV of a more geographically diversified fund. If securities of issuers in Europe fall out of favor, it may cause the Fund to underperform other funds that do not focus their investments in this region of the world. The departure of the United Kingdom (UK) from the EU single market became effective January 1, 2021 with the end of the Brexit transition period and the post-Brexit trade deal between the UK and EU taking effect on December 31, 2020. The impact of any partial or complete dissolution of the EU on the UK and European economies and the broader global economy could be significant, resulting in negative impacts on currency and financial markets generally, such as increased volatility and illiquidity, and potentially lower economic growth in markets in Europe, which may adversely affect the value of your investment in the Fund. 

Emerging Market Securities Risk. Securities issued by foreign governments or companies in emerging market countries are more likely to have greater exposure to the risks of investing in foreign securities that are described in Foreign Securities Risk. In addition, emerging market countries are more likely to experience instability resulting, for example, from rapid changes or developments in social, political, economic or other conditions. Their economies are usually less mature and their securities markets are typically less developed with more limited trading activity (i.e., lower trading volumes and less liquidity) than more developed countries. Emerging market securities tend to be more volatile, and may be more susceptible to market manipulation, than securities in more developed markets. Many emerging market countries are heavily dependent on international trade and have fewer trading partners, which makes them more sensitive to world commodity prices and economic downturns in other countries, and some have a higher risk of currency devaluations. Due to the differences in the nature and quality of financial information of issuers of emerging market securities, including auditing and financial reporting standards, financial information and disclosures about such issuers may be unavailable or, if made available, may be considerably less reliable than publicly available information about other foreign securities. 

Operational and Settlement Risks of Securities in Emerging Markets. Foreign sub-custodians in emerging markets may be recently organized, lack extensive operating experience or lack effective government oversight or regulation. In addition, there may be legal restrictions or limitations on the ability of the Fund to recover assets held in custody by a foreign sub-custodian in the event of the bankruptcy of the sub-custodian. There may also be a greater risk that settlement may be delayed and that cash or securities of the Fund may be lost because of failures of or defects in the system, including fraud or corruption. Settlement systems in emerging markets also have a higher risk of failed trades. 

Risks Related to Currencies and Corporate Actions in Emerging Markets. Risks related to currencies and corporate actions are also greater in emerging market countries than in developed countries. Emerging market currencies may not have an active trading market and are subject to a higher risk of currency devaluations. 

Risks Related to Corporate and Securities Laws in Emerging Markets. Securities laws in emerging markets may be relatively new and unsettled and, consequently, there is a risk of rapid and unpredictable change in laws regarding foreign investment, securities regulation, title to securities and shareholder rights. 

Foreign Currency Risk. The performance of the Fund may be materially affected positively or negatively by foreign currency strength or weakness relative to the U.S. dollar, particularly if the Fund invests a significant percentage of its assets in foreign securities or other assets denominated in currencies other than the U.S. dollar. 

Issuer Risk. An issuer in which the Fund invests may perform poorly, and the value of its securities may therefore decline, which may negatively affect the Fund’s performance. Underperformance of an issuer may be caused by poor management decisions, competitive pressures, breakthroughs in technology, reliance on suppliers, labor problems or shortages, corporate restructurings, fraudulent disclosures, natural disasters, military confrontations and actions, war, terrorism, disease/virus outbreaks and epidemics or other events, conditions and factors. 

Growth Securities Risk. Growth securities typically trade at a higher multiple of earnings than other types of equity securities. Accordingly, the market values of growth securities may never reach their expected market value and may decline in price. In addition, growth securities, at times, may not perform as well as value securities or the stock market in general, and may be out of favor with investors for varying periods of time. 

8 Prospectus 2022

Columbia Acorn European Fund^SM

Summary of the Fund (continued)

Performance Information

The following bar chart and table show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. The bar chart shows how the Fund’s Class Inst share performance has varied for each full calendar year shown. The table below the bar chart compares the Fund’s returns for the periods shown with the MSCI AC Europe Small Cap Index (Net). The MSCI AC Europe Small Cap Index (Net) captures small-cap representation across 20 countries in Europe.  It has 1,130 constituents and covers approximately 14% of the free float-adjusted market capitalization across each country in Europe (as of March 31, 2022).

The performance of one or more share classes shown in the Average Annual Total Returns table below includes the Fund’s Class Inst share returns (adjusted to reflect the higher class-related operating expenses of such classes, where applicable) for periods prior to the indicated inception date of such share classes. Except for differences in fees and expenses, all share classes of the Fund would have substantially similar annual returns because all share classes of the Fund invest in the same portfolio of securities. 

The after-tax returns shown in the Average Annual Total Returns table below are calculated using the highest historical individual U.S. federal marginal income tax rates in effect during the period indicated in the table and do not reflect the impact of state, local or foreign taxes. Your actual after-tax returns will depend on your personal tax situation and may differ from those shown in the table. In addition, the after-tax returns shown in the table do not apply to shares held in tax-advantaged accounts such as 401(k) plans or Individual Retirement Accounts (IRAs). The after-tax returns are shown only for Class Inst shares and will vary for other share classes. 

The Fund’s past performance (before and after taxes) is no guarantee of how the Fund will perform in the future. Updated performance information can be obtained by calling toll-free 800.345.6611 or visiting columbiathreadneedleus.com. 

Year by Year Total Return (%) as of December 31 Each Year*	Best and Worst Quarterly Returns During the Period Shown in the Bar Chart
	Best	2nd Quarter 2020	30.55%
	Worst	1st Quarter 2020	-28.33%

* Year to Date return as of March 31, 2022: -21.84%

Prospectus 2022 9

Columbia Acorn European Fund^SM

Summary of the Fund (continued)

 Average Annual Total Returns After Applicable Sales Charges (for periods ended December 31, 2021)

	Share Class Inception Date	1 Year	5 Years	10 Years
Class Inst	08/19/2011
returns before taxes		21.76%	19.83%	14.54%
returns after taxes on distributions		21.69%	19.70%	14.42%
returns after taxes on distributions and sale of Fund shares		13.02%	16.25%	12.36%
Class A returns before taxes	08/19/2011	14.47%	18.11%	13.58%
Class Adv returns before taxes	06/25/2014	21.75%	19.83%	14.55%
Class C returns before taxes	08/19/2011	19.57%	18.64%	13.40%
Class Inst2 returns before taxes	11/08/2012	21.80%	19.90%	14.58%
Class Inst3 returns before taxes	03/01/2017	21.83%	19.93%	14.58%
MSCI AC Europe Small Cap Index (Net) (reflects reinvested dividends net of withholding taxes but reflects no deductions for fees, expenses or other taxes)		14.74%	12.84%	12.67%

Fund Management

Investment Manager: Columbia Wanger Asset Management, LLC

Portfolio Management	Title	Role with Fund	Service with the Fund Since
Stephen Kusmierczak, CFA	International Team Head, Portfolio Manager and Analyst	Portfolio Manager or Co-Portfolio Manager since inception in 2011	2011
Sebastien Pigeon, CFA	Portfolio Manager and Analyst	Co-Portfolio Manager since 2021	2015

Purchase and Sale of Fund Shares

You may purchase or redeem shares of the Fund on any business day by contacting the Fund in the ways described below:

Online	Regular Mail	Express Mail	By Telephone
columbiathreadneedleus.com/investor/	Columbia Management Investment Services Corp. P.O. Box 219104 Kansas City, MO 64121-9104	Columbia Management Investment Services Corp. c/o DST Asset Manager Solutions, Inc. 430 W 7th Street, Suite 219104 Kansas City, MO 64105-1407	800.422.3737

You may purchase shares and receive redemption proceeds by electronic funds transfer, by check or by wire. If you maintain your account with a broker-dealer or other financial intermediary, you must contact that financial intermediary to buy, sell or exchange shares of the Fund through your account with the intermediary.

The minimum initial investment amounts for the share classes offered by the Fund are shown below:

Minimum Initial Investment

Class	Category of eligible account	For accounts other than Systematic Investment Plan accounts (as described in the Fund’s Prospectus)	For Systematic Investment Plan accounts
Classes A & C	All accounts other than IRAs	$2,000	$100
	IRAs	$1,000	$100

10 Prospectus 2022

Columbia Acorn European Fund^SM

Summary of the Fund (continued)

Class	Category of eligible account	For accounts other than Systematic Investment Plan accounts (as described in the Fund’s Prospectus)	For Systematic Investment Plan accounts
Classes Adv & Inst	All eligible accounts	$0, $1,000 or $2,000 depending upon the category of eligible investor	$100
Class Inst2	All eligible accounts	None	N/A
Class Inst3	All eligible accounts	$0, $1,000, $2,000 or $1 million depending upon the category of eligible investor	$100 (for certain eligible investors)

More information about these minimums can be found in the Buying, Selling and Exchanging Shares - Buying Shares section of the prospectus. There is no minimum additional investment for any share class.

Tax Information

The Fund normally distributes net investment income and net realized capital gains, if any, to shareholders. These distributions are generally taxable to you as ordinary income, qualified dividend income or capital gains, unless you are investing through a tax-advantaged account, such as a 401(k) plan or an IRA. If you are investing through a tax-advantaged account, you may be taxed upon withdrawals from that account.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase the Fund through a broker-dealer or other financial intermediary (such as a bank), the Fund and its related companies – including the Investment Manager, the Distributor and Columbia Management Investment Services Corp. (the Transfer Agent) – may pay the intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your financial advisor to recommend the Fund over another investment. These potential conflicts of interest may be heightened with respect to broker-dealers owned by Ameriprise Financial, Inc. (Ameriprise Financial) and/or its affiliates. Ask your financial advisor or visit your financial intermediary's website for more information.

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More Information About the Fund

Investment Objective

Columbia Acorn European Fund^SM (the Fund) seeks long-term capital appreciation. The Fund’s investment objective is not a fundamental policy of the Fund and may be changed by the Fund’s Board of Trustees (the Board) without shareholder approval. There is no assurance the Fund’s objective will be achieved.

Principal Investment Strategies

Under normal circumstances, the Fund invests at least 80% of its net assets (plus any borrowing for investment purposes) in European companies. Under normal circumstances, the Fund invests at least 70% of its total assets in companies in Western European countries (for example, the United Kingdom, Germany, France and Italy), but also may invest up to 30% of its total assets in companies in emerging Central and Eastern European countries (for example, Poland, the Czech Republic, Turkey and Cyprus). For purposes of the Fund's policies, the Fund may invest in a company if (i) it is domiciled in, or the principal trading market for its securities is in, a European country, (ii) it derives 50% or more of its economic value from goods produced, sales made or services performed or has at least 50% of its assets in a European country or countries or (iii) it is a holding company that predominantly holds shares in such companies. The Fund may invest in a variety of countries, industries and sectors and does not attempt to invest a specific percentage of its assets in any given country, industry or sector.

Under normal circumstances, the Fund invests a majority of its net assets in the common stock of small- and mid-sized companies with market capitalizations generally in the range of market capitalizations in the MSCI AC Europe Small Cap Index (Net), the Fund's benchmark, (the Index) at the time of purchase (between $85.4 million and $10.6 billion as of March 31, 2022). The market capitalization range and composition of companies in the Index are subject to change. As such, the size of the companies in which the Fund invests may change. The Fund determines a company’s market capitalization at the time of investment. As long as a majority of its net assets are invested in companies within the Index, the Fund may continue to hold and make new investments in a security even if the company’s market capitalization grows beyond the market capitalization of the largest company within the Index or falls below the market capitalization of the smallest company within the Index. The Investment Manager from time to time emphasizes one or more sectors in selecting the Fund’s investments, including the industrials, information technology, and health care sectors.

Columbia Wanger Asset Management, LLC, the Fund's investment adviser (the Investment Manager), believes that stocks of small- and mid-sized companies, which generally are not as well known by financial analysts as larger companies, may offer higher return potential than stocks of larger companies.

The Fund takes advantage of the Investment Manager's research and stock-picking capabilities to initially invest in a limited number of companies (generally under 100), offering the potential to provide above-average growth over time.

The Investment Manager typically seeks companies with:

■ A strong business franchise that offers growth potential.

■ Products and services in which the company has a competitive advantage.

■ A stock price the Investment Manager believes is reasonable relative to the assets and earning power of the company.

The Investment Manager may sell a portfolio holding if the security reaches the Investment Manager's price target, if the company has a deterioration of fundamentals, such as failing to meet key operating benchmarks, or if the Investment Manager believes other securities are more attractive. The Investment Manager also may sell a portfolio holding to fund redemptions.

Principal Risks

An investment in the Fund involves risks, including those described below, among others. There is no assurance that the Fund will achieve its investment objective and you may lose money. The value of the Fund’s holdings may decline, and the Fund’s net asset value (NAV) and share price may go down. An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

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Active Management Risk. The Fund is actively managed and its performance therefore will reflect, in part, the ability of the Investment Manager to select investments and to make investment decisions that will achieve the Fund’s investment objective. The Investment Manager’s active management of the Fund could cause the Fund to underperform its benchmark index and/or other funds with similar investment objectives and/or strategies.

Market Risk. The Fund may incur losses due to declines in the value of one or more securities in which it invests. These declines may be due to factors affecting a particular issuer, or the result of, among other things, political, regulatory, market, economic or social developments affecting the relevant market(s) more generally. In addition, turbulence in financial markets and reduced liquidity in equity, credit and/or fixed income markets may negatively affect many issuers, which could adversely affect the Fund’s ability to price or value hard-to-value assets in thinly traded and closed markets and could cause significant redemptions and operational challenges. Global economies and financial markets are increasingly interconnected, and conditions and events in one country, region or financial market may adversely impact issuers in a different country, region or financial market. These risks may be magnified if certain events or developments adversely interrupt the global supply chain; in these and other circumstances, such risks might affect companies worldwide. As a result, local, regional or global events such as terrorism, war, other conflicts, natural disasters, disease/virus outbreaks and epidemics or other public health issues, recessions, depressions or other events – or the potential for such events – could have a significant negative impact on global economic and market conditions.

The large-scale invasion of Ukraine by Russia in February 2022 has resulted in sanctions and market disruptions including declines in regional and global stock and commodity markets and significant devaluations of Russian currency. The extent and duration of the military action are impossible to predict but could be significant. Market disruption caused by the Russian military action, and any counter measures or responses thereto (including international sanctions, a downgrade in the country’s credit rating, purchasing and financing restrictions, boycotts, tariffs, changes in consumer or purchaser preferences, cyberattacks and espionage) could have severe adverse impacts on regional and/or global securities and commodities markets, including markets for oil and natural gas. These impacts may include reduced market liquidity, distress in credit markets, further disruption of global supply chains, increased risk of inflation, and limited access to investments in certain international markets and/or issuers. These developments and other related events could negatively impact Fund performance.

The pandemic caused by coronavirus disease 2019 and its variants (COVID-19) has resulted in, and may continue to result in, significant global economic and societal disruption and market volatility due to disruptions in market access, resource availability, facilities operations, imposition of tariffs, export controls and supply chain disruption, among others. Such disruptions may be caused, or exacerbated by, quarantines and travel restrictions, workforce displacement and loss in human and other resources. The uncertainty surrounding the magnitude, duration, reach, costs and effects of the global pandemic, as well as actions that have been or could be taken by governmental authorities or other third parties, present unknowns that are yet to unfold. The impacts, as well as the uncertainty over impacts to come, of COVID-19 – and any other infectious illness outbreaks, epidemics and pandemics that may arise in the future – could negatively affect global economies and markets in ways that cannot necessarily be foreseen. In addition, the impact of infectious illness outbreaks and epidemics in emerging market countries may be greater due to generally less established healthcare systems, governments and financial markets. Public health crises caused by the COVID-19 outbreak may exacerbate other pre-existing political, social and economic risks in certain countries or globally. The disruptions caused by COVID-19 could prevent the Fund from executing advantageous investment decisions in a timely manner and negatively impact the Fund’s ability to achieve its investment objective. Any such events could have a significant adverse impact on the value and risk profile of the Fund.

Liquidity and Trading Volume Risk. Due to market conditions, including uncertainty regarding the price of a security, it may be difficult for the Fund to buy or sell portfolio securities at a desirable time or price, which could result in investment losses. This risk of portfolio illiquidity is heightened with respect to small- and mid-cap securities, generally, and foreign small- and mid-cap securities in particular. The Fund may have to lower the selling price, liquidate other investments, or forego another, more appealing investment opportunity as a result of illiquidity in the markets. The Investment Manager will fair value in good faith any securities it deems to be illiquid under consistently applied procedures established by the Fund’s Board. Market conditions are always changing and vary by country and

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industry sector, and investing in international markets involves unique risks. Although it is difficult to accurately assess trends in trading volumes in foreign markets, a reduction in trading volumes poses challenges to the Fund. This is particularly so because the Fund focuses on small- and mid-cap companies that usually have lower trading volumes and often takes sizeable positions in portfolio companies. As a result of lower trading volumes, it may take longer to buy or sell securities, which can exacerbate the Fund’s exposure to volatile markets. The Fund may also be limited in its ability to execute favorable trades in portfolio securities in response to changes in share prices and fundamentals. If the Fund is forced to sell securities to meet redemption requests or other cash needs, or in the case of an event affecting liquidity in a particular market or markets, it may be forced to dispose of those securities under disadvantageous circumstances and at a loss. As the Fund grows in size or, conversely, if it faces significant redemption pressure, these considerations take on increasing significance and may adversely impact performance.

Small- and Mid-Cap Company Securities Risk. Securities of small- and mid-cap companies can, in certain circumstances, have a higher potential for gains than securities of larger, more established companies but may also have more risk. For example, small- and mid-cap companies may be more vulnerable to market downturns and adverse business or economic events than larger companies because they may have more limited financial resources and business operations. Small- and mid-cap companies are also more likely than larger companies to have more limited product lines and operating histories and to depend on smaller and generally less experienced management teams. Securities of small- and mid-cap companies may trade less frequently and in smaller volumes and may be less liquid and fluctuate more sharply in value than securities of larger companies. When the Fund takes significant positions in small- and mid-cap companies with limited trading volumes, the liquidation of those positions, particularly in a distressed market, could be prolonged and result in Fund investment losses that would affect the value of your investment in the Fund. In addition, some small- and mid-cap companies may not be widely followed by the investment community, which can lower the demand for their stocks.

Sector Risk. At times, the Fund may have a significant portion of its assets invested in securities of companies conducting business within one or more economic sectors, including the industrials, information technology, and health care sectors. Companies in the same sector may be similarly affected by economic, regulatory, political or market events or conditions, which may make the Fund more vulnerable to unfavorable developments in that sector than funds that invest more broadly. Generally, the more broadly the Fund invests, the more it spreads risk and potentially reduces the risks of loss and volatility.

■ Industrials Sector. The Fund is more susceptible to the particular risks that may affect companies in the industrials sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the industrials sector are subject to certain risks, including changes in supply and demand for their specific product or service and for industrial sector products in general, including decline in demand for such products due to rapid technological developments and frequent new product introduction. Performance of such companies may be affected by factors including government regulation, world events, economic conditions and risks for environmental damage and product liability claims.

■ Information Technology Sector. The Fund is more susceptible to the particular risks that may affect companies in the information technology sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the information technology sector are subject to certain risks, including the risk that new services, equipment or technologies will not be accepted by consumers and businesses or will become rapidly obsolete. Performance of such companies may be affected by factors including obtaining and protecting patents (or the failure to do so) and significant competitive pressures, including aggressive pricing of their products or services, new market entrants, competition for market share and short product cycles due to an accelerated rate of technological developments. Such competitive pressures may lead to limited earnings and/or falling profit margins. As a result, the value of their securities may fall or fail to rise. In addition, many information technology sector companies have limited operating histories and prices of these companies’ securities historically have been more volatile than other securities, especially over the short term. Some companies in the information technology sector are facing increased government and regulatory scrutiny and may be subject to adverse government or regulatory action, which could negatively impact the value of their securities.

■ Health Care Sector. The Fund is more susceptible to the particular risks that may affect companies in the health care sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the health

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care sector are subject to certain risks, including restrictions on government reimbursement for medical expenses, government approval of medical products and services, competitive pricing pressures, and the rising cost of medical products and services (especially for companies dependent upon a relatively limited number of products or services), among others. Performance of such companies may be affected by factors including, government regulation, obtaining and protecting patents (or the failure to do so), product liability and other similar litigation as well as product obsolescence.

Foreign Securities Risk. Investments in or exposure to securities of foreign companies may involve heightened risks relative to investments in or exposure to securities of U.S. companies. For example, foreign markets can be extremely volatile. Foreign securities may also be less liquid, making them more difficult to trade, than securities of U.S. companies so that the Fund may, at times, be unable to sell foreign securities at desirable times or prices. Brokerage commissions, custodial costs and other fees are also generally higher for foreign securities. The Fund may have limited or no legal recourse in the event of default with respect to certain foreign securities, including those issued by foreign governments. In addition, foreign governments may impose withholding or other taxes on the Fund’s income, capital gains or proceeds from the disposition of foreign securities, which could reduce the Fund’s return on such securities. In some cases, such withholding or other taxes could potentially be confiscatory. Other risks include: possible delays in the settlement of transactions or in the payment of income; generally less publicly available information about foreign companies; the impact of economic, political, social, diplomatic or other conditions or events (including, for example, military confrontations and actions, war, other conflicts, terrorism and disease/virus outbreaks and epidemics), possible seizure, expropriation or nationalization of a company or its assets or the assets of a particular investor or category of investors; accounting, auditing and financial reporting standards that may be less comprehensive and stringent than those applicable to domestic companies; the imposition of economic and other sanctions against a particular foreign country, its nationals or industries or businesses within the country; and the generally less stringent standard of care to which local agents may be held in the local markets. In addition, it may be difficult to obtain reliable information about the securities and business operations of certain foreign issuers. Governments or trade groups may compel local agents to hold securities in designated depositories that are not subject to independent evaluation. The less developed a country’s securities market is, the greater the level of risks. Economic sanctions may be, and have been, imposed against certain countries, organizations, companies, entities and/or individuals. Economic sanctions and other similar governmental actions could, among other things, effectively restrict or eliminate the Fund’s ability to purchase or sell securities, and thus may make the Fund’s investments in such securities less liquid or more difficult to value. In addition, as a result of economic sanctions, the Fund may be forced to sell or otherwise dispose of investments at inopportune times or prices, which could result in losses to the Fund and increased transaction costs. These conditions may be in place for a substantial period of time and enacted with limited advance notice to the Fund. The risks posed by sanctions against a particular foreign country, its nationals or industries or businesses within the country may be heightened to the extent the Fund invests significantly in the affected country or region or in issuers from the affected country that depend on global markets. Additionally, investments in certain countries may subject the Fund to a number of tax rules, the application of which may be uncertain. Countries may amend or revise their existing tax laws, regulations and/or procedures in the future, possibly with retroactive effect. Changes in or uncertainties regarding the laws, regulations or procedures of a country could reduce the after-tax profits of the Fund, directly or indirectly, including by reducing the after-tax profits of companies located in such countries in which the Fund invests, or result in unexpected tax liabilities for the Fund.

Operational and Settlement Risks of Foreign Securities. The Fund’s foreign securities are generally held outside the United States in the primary market for the securities in the custody of certain eligible foreign banks and trust companies (“foreign sub-custodians”), as permitted under the Investment Company Act of 1940 (the 1940 Act). Settlement practices for foreign securities may differ from those in the United States. Some countries have limited governmental oversight and regulation of industry practices, stock exchanges, depositories, registrars, brokers and listed companies, which increases the risk of corruption and fraud and the possibility of losses to the Fund. In particular, under certain circumstances, foreign securities may settle on a delayed delivery basis, meaning that the Fund may be required to make payment for securities before the Fund has actually received delivery of the securities or deliver securities prior to the receipt of payment. Typically, in these cases, the Fund will receive evidence of ownership in accordance with the generally accepted settlement practices in the local market entitling the Fund to delivery or payment at a future date, but there is a risk that the security will not be delivered to the Fund or that

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payment will not be received, although the Fund and its foreign sub-custodians take reasonable precautions to mitigate this risk. Losses can also result from lost, stolen or counterfeit securities; defaults by brokers and banks; failures or defects of the settlement system; or poor and improper record keeping by registrars and issuers.

Share Blocking. Share blocking refers to a practice in certain foreign markets under which an issuer’s securities are blocked from trading at the custodian or sub-custodian level for a specified number of days before and, in certain instances, after a shareholder meeting where a vote of shareholders takes place. The blocking period can last up to several weeks. Share blocking may prevent the Fund from buying or selling securities during this period, because during the time shares are blocked, trades in such securities will not settle. It may be difficult or impossible to lift blocking restrictions, with the particular requirements varying widely by country. As a consequence of these restrictions, the Investment Manager, on behalf of the Fund, may abstain from voting proxies in markets that require share blocking.

Geographic Focus Risk. The Fund may be particularly susceptible to risks related to economic, political, regulatory or other events or conditions affecting issuers and countries within the specific geographic regions in which the Fund invests. Currency devaluations could occur in countries that have not yet experienced currency devaluation to date, or could continue to occur in countries that have already experienced such devaluations. As a result, the Fund’s NAV may be more volatile than the NAV of a more geographically diversified fund.

■ Europe. The Fund is particularly susceptible to risks related to economic, political, regulatory or other events or conditions, including acts of war or other conflicts in the region, affecting issuers and countries in Europe. Countries in Europe are often closely connected and interdependent, and events in one European country can have an adverse impact on, and potentially spread to, other European countries. Most developed countries in Western Europe are members of the EU, and many are also members of the European Economic and Monetary Union (EMU). European countries can be significantly affected by the tight fiscal and monetary controls that the EMU imposes on its members and with which candidates for EMU membership are required to comply. In addition, significant private and public sectors’ debt problems of a single EU country can pose economic risks to the EU as a whole. Unemployment in Europe has historically been higher than in the United States and public deficits are an ongoing concern in many European countries. As a result, the Fund’s NAV may be more volatile than the NAV of a more geographically diversified fund. If securities of issuers in Europe fall out of favor, it may cause the Fund to underperform other funds that do not focus their investments in this region of the world. The UK’s departure from the EU single market became effective January 1, 2021 with the end of the Brexit transition period and the post‐Brexit trade deal between the UK and EU taking effect on December 31, 2020. The impact of any partial or complete dissolution of the EU on the UK and European economies and the broader global economy could be significant, resulting in negative impacts on currency and financial markets generally, such as increased volatility and illiquidity, and potentially lower economic growth in markets in the UK, Europe and globally, which may adversely affect the value of your investment in the Fund. The impact of Brexit in the near‐ and long‐term is still unknown and could have additional adverse effects on economies, financial markets, currencies and asset valuations around the world. Any attempt by the Fund to hedge against or otherwise protect its portfolio or to profit from such circumstances may fail and, accordingly, an investment in the Fund could lose money over short or long periods. For more information on the risks associated with Brexit, see the Statement of Additional Information.

Emerging Market Securities Risk. Securities issued by foreign governments or companies in emerging market countries are more likely to have greater exposure to the risks of investing in foreign securities that are described in Foreign Securities Risk. In addition, emerging market countries are more likely to experience instability resulting, for example, from rapid changes or developments in social, political, economic or other conditions. Their economies are usually less mature and their securities markets are typically less developed with more limited trading activity (i.e., lower trading volumes and less liquidity) than more developed countries. Emerging market securities tend to be more volatile, and may be more susceptible to market manipulation, than securities in more developed markets. Many emerging market countries are heavily dependent on international trade and have fewer trading partners, which makes them more sensitive to world commodity prices and economic downturns in other countries. Some emerging market countries have a higher risk of currency devaluations, and some of these countries may experience periods of high inflation or rapid changes in inflation rates and may have hostile relations with other countries. Due to the

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differences in the nature and quality of financial information of issuers of emerging market securities, including auditing and financial reporting standards, financial information and disclosures about such issuers may be unavailable or, if made available, may be considerably less reliable than publicly available information about other foreign securities.

Operational and Settlement Risks of Securities in Emerging Markets. In addition to having less developed securities markets, banks in emerging markets that are eligible foreign sub-custodians may be recently organized, lack extensive operating experience or lack effective government oversight or regulation. In addition, there may be legal restrictions or limitations on the ability of the Fund to recover assets held in custody by a foreign sub-custodian in the event of the bankruptcy of the sub-custodian. Because settlement systems may be less organized than in developed markets and because delivery versus payment settlement may not be possible or reliable, there may be a greater risk that settlement may be delayed and that cash or securities of the Fund may be lost because of failures of or defects in the system, including fraud or corruption. Settlement systems in emerging markets also have a higher risk of failed trades.

Risks Related to Currencies and Corporate Actions in Emerging Markets. Risks related to currencies and corporate actions are also greater in emerging market countries than in developed countries. For example, some emerging market countries may have fixed or managed currencies that are not free-floating against the U.S. dollar. Further, certain currencies may not have an active trading market internationally, or countries may have varying exchange rates. Some emerging market countries have a higher risk of currency devaluations, and some of these countries may experience sustained periods of high inflation or rapid changes in inflation rates which can have negative effects on a country’s economy and securities markets. Corporate action procedures in emerging market countries may be less reliable and have limited or no involvement by the depositories and central banks. Lack of standard practices and payment systems can lead to significant delays in payment.

Risks Related to Corporate and Securities Laws in Emerging Markets. Securities laws in emerging markets may be relatively new and unsettled and, consequently, there is a risk of rapid and unpredictable change in laws regarding foreign investment, securities regulation, title to securities and shareholder rights. Accordingly, foreign investors may be adversely affected by new or amended laws and regulations. In addition, the systems of corporate governance to which issuers in certain emerging markets are subject may be less advanced than the systems to which issuers located in more developed countries are subject, and therefore, shareholders of such issuers may not receive many of the protections available to shareholders of issuers located in more developed countries. These risks may be heightened in China and Russia.

Foreign Currency Risk. The performance of the Fund may be materially affected positively or negatively by foreign currency strength or weakness relative to the U.S. dollar, particularly if the Fund invests a significant percentage of its assets in foreign securities or other assets denominated in currencies other than the U.S. dollar. Currency rates in foreign countries may fluctuate significantly over short or long periods of time for a number of reasons, including changes in interest rates, imposition of currency controls and economic or political developments in the U.S. or abroad. The Fund may also incur currency conversion costs when converting foreign currencies into U.S. dollars and vice versa. Restrictions on currency trading may be imposed by foreign countries, which may adversely affect the value of your investment in the Fund. Even though the currencies of some countries may be pegged to the U.S. dollar, the conversion rate may be controlled by government regulation or intervention at levels significantly different than what would normally prevail in a free market. Significant revaluations of the U.S. dollar exchange rate of these currencies could cause substantial reductions in the Fund’s NAV.

Issuer Risk. An issuer in which the Fund invests may perform poorly, and the value of its securities may therefore decline, which may negatively affect the Fund’s performance. Underperformance of an issuer may be caused by poor management decisions, competitive pressures, breakthroughs in technology, reliance on suppliers, labor problems or shortages, corporate restructurings, fraudulent disclosures, natural disasters, military confrontations and actions, war, terrorism, disease/virus outbreaks and epidemics or other events, conditions and factors.

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Growth Securities Risk. Growth securities typically trade at a higher multiple of earnings than other types of equity securities. Accordingly, the market values of growth securities may never reach their expected market value and may decline in price. In addition, growth securities, at times, may not perform as well as value securities or the stock market in general, and may be out of favor with investors for varying periods of time.

Additional Investment Strategies and Policies

This section describes certain investment strategies and policies that the Fund may utilize in pursuit of its investment objective and some additional factors and risks involved with investing in the Fund. For information about risks associated with changing levels of Fund distributions, see the SAI.

Changing the Fund’s Investment Objective and Policies

The Fund’s investment objective and non-fundamental investment policies (including its principal and additional investment strategies) can be changed by the Board without shareholder approval, but may require notice to shareholders in certain instances. The Fund’s fundamental investment policies, as identified in the Fund’s Statement of Additional Information (SAI), may be changed only with Board and shareholder approval in accordance with the voting requirements of the 1940 Act. For additional information about changing the Fund’s fundamental and non-fundamental investment policies, see the SAI.

Investment Guidelines

As a general matter, and except as specifically described in the discussion of the Fund's principal investment strategies in this prospectus, whenever an investment policy or limitation states a percentage of the Fund's assets that may be invested in any security or other asset or sets forth a policy regarding an investment standard, compliance with that percentage limitation or standard will be determined based on the characteristics of a company at the time of initial purchase, and subsequent changes in a characteristic are not taken into account.

Holding Other Kinds of Investments

The Fund may hold other investments that are not part of its principal investment strategies. These investments and their risks are described below and/or in the SAI. The Fund may choose not to invest in certain securities described in this prospectus and in the SAI, although it has the ability to do so. Information on the Fund’s holdings can be found in the Fund’s shareholder reports or by visiting columbiathreadneedleus.com.

Transactions in Derivatives

The Fund may enter into derivative transactions or otherwise have exposure to derivative transactions through underlying investments. The Fund expects to enter into such transactions primarily in the form of stock index futures in order to obtain exposure to the overall sector of the market represented by a particular stock index or to invest the Fund’s uninvested cash balances in a manner that the Investment Manager believes aligns more closely with the Fund’s investment strategy than simply holding short-term fixed income investments or cash equivalents (known as cash equitization). Derivatives are financial contracts whose values are, for example, based on (or “derived” from) traditional securities (such as a stock or bond), assets (such as a commodity like gold or a foreign currency), reference rates (such as the Secured Overnight Financing Rate (commonly known as SOFR) or the London Interbank Offered Rate (commonly known as LIBOR)) or market indices (such as the Standard & Poor's (S&P) 500^® Index). The use of derivatives is a highly specialized activity which involves investment techniques and risks different from those associated with ordinary portfolio securities transactions. Derivatives involve special risks and may result in losses or may limit the Fund's potential gain from favorable market movements. Derivative strategies typically expose the Fund to gains and losses in excess of the amount actually invested in the derivative. This characteristic of a derivative (known as "leverage") may exaggerate a loss, potentially causing the Fund to lose more money than it would have lost had it invested in the underlying security or other asset directly. The values of derivatives may move in unexpected ways, especially in unusual (including distressed) market conditions, and may result in increased volatility in the value of the derivative and/or the Fund’s shares, among other consequences. The use of derivatives may also increase the amount of taxes payable by shareholders holding shares in a taxable account. Other risks arise from the Fund's potential inability to terminate or to sell derivative positions. A liquid secondary market may not always exist for the Fund's derivative positions at times when the Fund might wish to terminate or to sell such

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positions. Over-the-counter instruments (investments not traded on an exchange) may be illiquid, and transactions in derivatives traded in the over-the-counter market are subject to the risk that the other party will not meet its obligations. The use of derivatives also involves the risks of mispricing or improper valuation and that changes in the value of the derivative may not correlate perfectly with the underlying security, asset, reference rate or index. The Fund also may not be able to find a suitable derivative transaction counterparty, and thus may be unable to engage in derivative transactions when it is deemed favorable to do so, or at all. U.S. federal legislation has been enacted that provides for new clearing, margin, reporting and registration requirements for participants in the derivatives market. These changes could restrict and/or impose significant costs or other burdens upon the Fund’s participation in derivatives transactions. The U.S. government and the European Union (and some other jurisdictions) have enacted regulations and similar requirements that prescribe clearing, margin, reporting and registration requirements for participants in the derivatives market. These requirements are evolving and their ultimate impact on the Fund remains unclear but such impact could include restricting and/or imposing significant costs or other burdens upon the Fund’s participation in derivatives transactions. Additionally, in October 2020, the SEC adopted new regulations governing the use of derivatives by registered investment companies. Once effective, Rule 18f-4 will, among other things, require funds that invest in derivative instruments beyond a specified limited amount to apply a value-at-risk based limit to their use of certain derivative instruments and establish a comprehensive derivatives risk management program. A fund that uses derivative instruments in a limited amount will not be subject to the full requirements of Rule 18f-4. Compliance with Rule 18f-4 will not be required until August 2022. Rule 18f-4 could have an adverse impact on the Fund’s performance and ability to implement its investment strategies as it has historically. For more information on the risks of derivative investments and strategies, see the SAI.

LIBOR Phase-Out Risk. Many derivatives and other financial instruments utilize or are permitted to utilize a floating interest rate based on LIBOR. On July 27, 2017, the United Kingdom's Financial Conduct Authority (FCA) announced its intention to phase out the use of LIBOR by the end of 2021. The FCA and the ICE Benchmark Administration have since announced that a majority of U.S. dollar LIBOR settings will cease publication after June 30, 2023. A subset of non-U.S. dollar LIBOR settings are continuing to be published on a “synthetic” basis and it is possible that a subset of U.S. dollar LIBOR settings will also be published after June 30, 2023 on a “synthetic” basis. Any such publications are, or would be considered, non-representative of the underlying market. Uncertainty related to the liquidity impact of changes in reference rates, and how to appropriately adjust these rates at the time of transition, poses risks for the Fund. It is difficult to predict the full impact of the transition away from LIBOR on the Fund until new reference rates and fallbacks for both legacy and new products, instruments and contracts are commercially accepted and market practices become more settled. The Investment Manager monitors the Fund's LIBOR exposure risks, including the extent to which any derivative and/or debt investments allow for the utilization of alternative rate(s), such as the Secured Overnight Financing Rate (SOFR), which the U.S. Federal Reserve is promoting as the alternative reference rate to LIBOR.

Affiliated Fund Investing

The Investment Manager and its affiliate, Columbia Management Investment Advisers, LLC (Columbia Management), each serves as investment adviser to mutual funds and ETFs using the Columbia brand (Columbia Funds), including mutual funds that are structured as “fund-of-funds”, and provides asset-allocation services to (i) shareholders by investing in shares of other Columbia Funds, which may include the Fund (collectively referred to in this section as Underlying Funds), and (ii) discretionary managed accounts (collectively referred to as affiliated products) that invest exclusively in Underlying Funds. These affiliated products, individually or collectively, may own a significant percentage of the outstanding shares of one or more Underlying Funds, and the Investment Manager and Columbia Management seek to balance potential conflicts of interest between the affiliated products and the Underlying Funds in which they invest. The affiliated products’ investment in the Underlying Funds may have the effect of creating economies of scale, possibly resulting in lower expense ratios for the Underlying Funds, because the affiliated products may own substantial portions of the shares of Underlying Funds. However, redemption of Underlying Fund shares by one or more affiliated products could cause the expense ratio of the Underlying Fund to increase, as its fixed costs would be spread over a smaller asset base. Because of large positions of certain affiliated products, the Underlying Funds may experience relatively large inflows and outflows of cash due to affiliated products’ purchases and sales of Underlying Fund shares. Although the Investment Manager or Columbia Management may seek to

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minimize the impact of these transactions where possible, for example, by structuring them over a reasonable period of time or through other measures, Underlying Funds may experience increased expenses as they buy and sell portfolio securities to manage the cash flow effect related to these transactions. Further, when the Investment Manager or Columbia Management structures transactions over a reasonable period of time in order to manage the potential impact of the buy and sell decisions for the affiliated products, those affiliated products, including funds-of-funds, may pay more or less (for purchase activity), or receive more or less (for redemption activity), for shares of the Underlying Funds than if the transactions were executed in one transaction. In addition, substantial redemptions by affiliated products within a short period of time could require the Underlying Fund to liquidate positions more rapidly than would otherwise be desirable, which may have the effect of reducing or eliminating potential gain or causing it to realize a loss. In order to meet such redemptions, the Underlying Fund may be forced to sell its liquid (or more liquid) positions, leaving the Underlying Fund holding, post-redemption, a relatively larger position in illiquid investments (i.e., any investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without the sale or disposition significantly changing the market value of the investment) or less liquid securities. Substantial redemptions may also adversely affect the ability of the Underlying Fund to implement its investment strategy. The Investment Manager or Columbia Management also has a conflict of interest in determining the allocation of affiliated products’ assets among the Underlying Funds, as it earns different fees from the various Underlying Funds.

Investing in Money Market Funds

The Fund may invest cash, including cash collateral received in connection with its securities lending program, in shares of money market funds, including funds advised by affiliates of the Investment Manager. These funds are not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency. The Fund and its shareholders indirectly bear a portion of the expenses of any money market fund or other fund in which the Fund may invest.

Lending of Portfolio Securities

The Fund may lend portfolio securities to broker-dealers or other financial intermediaries on a fully collateralized basis in order to earn additional income. The Fund may lose money from securities lending if, for example, the borrower does not return a loaned security and the proceeds from sale of the collateral are not sufficient to replace the borrowed security. The Fund invests collateral in a government money market fund.

Investing Defensively

The Fund may from time to time take temporary defensive investment positions that are inconsistent with the Fund’s principal investment strategies in attempting to respond to adverse market, economic, political, social or other conditions. These investment positions may include, without limitation, investing some or all of its assets in money market instruments or shares of affiliated or unaffiliated money market funds or holding some or all of its assets in cash or cash equivalents. The Fund may take such defensive positions for as long a period as the Investment Manager deems necessary. During these times, the Investment Manager may make frequent portfolio changes, which could result in increased trading expenses and taxes, and decreased Fund performance.

Portfolio Holdings Disclosure

A description of the Fund’s policies and procedures with respect to the disclosure of Fund portfolio securities is available in the SAI. The Fund discloses its portfolio holdings on the Columbia Funds’ website, columbiathreadneedleus.com, as described below. Once posted, the portfolio holdings information will remain available on the website until at least the date on which such Fund files a Form N-CSR or publicly available Form N-PORT (forms filed with the SEC that include portfolio holdings information) for the period that includes the date as of which the information is current.

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The Fund considers changes in its portfolio holdings to be confidential information. Consequently, Fund policy generally permits the disclosure of portfolio holdings information only after a certain amount of time has passed. The Fund’s complete portfolio holdings are disclosed approximately 30 to 40 days after each month-end. The top 15 holdings may be available sooner, approximately 15 calendar days after each month-end. Purchases and sales of portfolio securities can take place at any time, so the portfolio holdings information available on the website may not always be current.

Cybersecurity

The Fund, like all companies, may be susceptible to operational and information security risks, including the risk of cyber attacks or failures. As a result, the Fund or its service providers, or the issuers of securities in which the Fund invests, may experience disruptions in business operations that may potentially result in financial losses, the inability of the Fund or Fund shareholders to transact business, violations of applicable privacy and other laws, regulatory fines, penalties, reputational damage, reimbursement or other compensation costs, and/or additional compliance costs. The Fund and its shareholders could be negatively impacted as a result. See the discussion of Cybersecurity Breaches and Technology and Related Systems Failure Risk in the SAI for further information.

Use of Benchmarks

Benchmarks are indices that provide some comparative guidance in assessing the Fund’s performance. The Investment Manager selects the benchmarks it believes provide meaningful comparisons for each Fund. However, there may be different or additional indices that more closely reflect the market sectors in which the Fund invests. The Fund’s benchmarks may change from time to time. The benchmarks included in this prospectus are intended only as guideposts for your assessment of the Fund’s performance.

 FUNDamentals

Portfolio Holdings Versus the Benchmarks

The Fund does not limit its investments to the securities within its benchmarks, and accordingly the Fund's holdings may diverge significantly from those of the benchmarks selected by the Investment Manager. In addition, the Fund may invest in securities outside the industry and geographic sectors represented in its benchmarks. The Fund's weightings in individual securities, and in industry and geographic sectors, may also vary considerably from those of its benchmarks.

eDelivery and Mailings to Households

In order to reduce shareholder expenses, the Fund may mail only one copy of the Fund’s prospectus and each annual and semiannual report to those addresses shared by two or more accounts. If you wish to receive separate copies of these documents, call 800.345.6611 or, if your shares are held through a financial intermediary, contact your intermediary directly. Additionally, you may elect to enroll in eDelivery to receive electronic versions of these documents, as well as quarterly statements and supplements, by logging into your account at columbiathreadneedleus.com/investor/.

Additional Information on Portfolio Turnover

A mutual fund that replaces, or turns over, more than 100% of its investments in a year may be considered to have a high portfolio turnover rate. A high portfolio turnover rate can generate larger distributions of short-term capital gains to shareholders, which for individuals are generally taxable at higher rates than long-term capital gains for U.S. federal income tax purposes. Also, a high portfolio turnover rate can mean higher brokerage commissions and other transaction costs, which could reduce a fund’s returns. In general, the greater the volume of buying and selling by a fund, the greater the impact that brokerage commissions and other transaction costs will have on its returns. The Fund may sell securities regardless of how long they’ve been held. See the Financial Highlights section of this prospectus for the Fund's portfolio turnover rates for the past five years.

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Cash Flows

The timing and magnitude of cash inflows from investors buying Fund shares could prevent the Fund from always being fully invested. Conversely, the timing and magnitude of cash outflows to shareholders redeeming Fund shares could require the Fund to sell portfolio securities at less than opportune times or to hold ready reserves of uninvested cash in amounts larger than might otherwise be the case to meet shareholder redemptions. Either situation could adversely impact the Fund’s performance.

Understanding Annual Fund Operating Expenses

The Fund’s annual operating expenses, as presented in the Annual Fund Operating Expenses table in the Fees and Expenses of the Fund section of this prospectus, generally are based on expenses incurred during the Fund’s most recently completed fiscal year, may vary by share class and are expressed as a percentage (expense ratio) of the Fund’s average net assets during that fiscal year. The expense ratios reflect the Fund’s fee arrangements as of the date of this prospectus and, unless indicated otherwise, are based on expenses incurred during the Fund’s most recent fiscal year. The Fund’s assets will fluctuate, but unless indicated otherwise in the Annual Fund Operating Expenses table, no adjustments have been or will be made to the expense ratios to reflect any differences in the Fund’s average net assets between the most recently completed fiscal year and the date of this prospectus or a later date. In general, the Fund’s expense ratios will increase as its net assets decrease, such that the Fund’s actual expense ratios may be higher than the expense ratios presented in the Annual Fund Operating Expenses table if assets fall. Any commitment by the Investment Manager and/or its affiliates to waive fees and/or cap (reimburse) expenses is expected, in part, to limit the impact of any increase in the Fund’s expense ratios that would otherwise result because of a decrease in the Fund’s assets in the current fiscal year. The Fund’s annual operating expenses are comprised of (i) investment management fees, (ii) distribution and/or service fees, and (iii) other expenses. Management fees do not vary by class, but distribution and/or service fees and other expenses may vary by class. Please see Fee Waiver/Expense Reimbursement Arrangements below for information about commitments made by the Investment Manager and/or its affiliates during the performance period covered by this prospectus.

 FUNDamentals

Other Expenses

“Other expenses” consist of the fees the Fund pays to its administrator, custodian, transfer agent, auditors, lawyers and trustees, costs relating to compliance and miscellaneous expenses. Generally, these expenses are allocated on a pro rata basis across all share classes. These expenses include certain sub-transfer agency and shareholder servicing fees. Transfer agency fees and certain shareholder servicing fees, however, are class specific. They differ by share class because the shareholder services provided to each share class may be different. Accordingly, the differences in “other expenses” among share classes are primarily the result of the different transfer agency and shareholder servicing fees applicable to each share class. For more information on these fees, see Choosing a Share Class — Financial Intermediary Compensation.

Fee Waiver/Expense Reimbursement Arrangements

The Investment Manager has contractually agreed to waive fees and reimburse certain expenses of the Fund through April 30, 2023, so that ordinary operating expenses (excluding transaction costs and certain other investment-related expenses, interest and fees on borrowings and expenses associated with the Fund’s investment in other investment companies, if any) do not exceed the annual rates of:

Columbia Acorn European Fund
Class A	1.45%
Class Adv	1.20%
Class C	2.20%
Class Inst	1.20%

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Columbia Acorn European Fund
Class Inst2	1.14%
Class Inst3	1.11%

This arrangement may only be amended or terminated with approval from the Fund’s Board of Trustees and the Investment Manager.

The Transfer Agent has contractually agreed to waive a portion of the fees payable by the Fund such that through April 30, 2023, fees paid by the Fund to the Transfer Agent do not exceed the annual rates of (i) 0.03% of the average daily net assets of Class Inst2 shares of the Fund and (ii) 0.00% of the average daily net assets of Class Inst3 shares of the Fund unless sooner terminated at the sole discretion of the Fund’s Board of Trustees.

Effect of Fee Waivers and/or Expense Reimbursements on Past Performance. The Fund’s returns shown in the Performance Information section of this prospectus reflect the effect of fee waivers and/or reimbursements of Fund expenses by the Investment Manager and/or its affiliates that were in place during the performance period shown in the Performance Information section of this prospectus. Without such fee waivers/expense reimbursements, the Fund’s returns might have been lower.

Board of Trustees

The Fund is governed by the Board. More than 75% of the Fund's Trustees are independent (Independent Trustees), meaning that they are not “interested persons” of the Fund, as defined in the 1940 Act. The Independent Trustees bring backgrounds in business and academia to their task of working with the Fund's officers to establish the Fund's policies and oversee its activities. Among the Trustees' responsibilities are: selecting the investment adviser for the Fund; approving the advisory agreement; reviewing other contracts; approving investment policies; monitoring Fund operations, performance, compliance and costs; and nominating or selecting new Trustees.

Each Trustee serves the Fund for an indefinite term until his or her retirement, resignation, death or removal in accordance with the organizational documents of Columbia Acorn Trust (the Trust). The Trust's Bylaws generally require that Trustees retire at the end of the calendar year in which they attain the age of 75 years. The last meeting to elect Trustees was held on February 27, 2015. Any Trustee may be removed at a shareholders' meeting by a vote representing two-thirds of the net asset value of all shares of the Columbia Acorn family of funds (Columbia Acorn Funds). The mailing address for the Trustees and officers is 71 S. Wacker Drive, Suite 2500, Chicago, Illinois 60606.

For more detailed information about the Board, please refer to the SAI.

Primary Service Provider Contracts

The Fund enters into contractual arrangements (Service Provider Contracts) with various parties, including, among others, the Investment Manager, the Distributor, the Transfer Agent and the Fund’s custodian. The Fund’s Service Provider Contracts are solely among the parties thereto. Shareholders are not parties to, or intended to be third-party beneficiaries of, any Service Provider Contracts. Further, this prospectus, the SAI and any Service Provider Contracts are not intended to give rise to any agreement, duty, special relationship or other obligation between the Fund and any investor, or give rise to any contractual, tort or other rights in any individual shareholder, group of shareholders or other person, including any right to assert a fiduciary or other duty, enforce the Service Provider Contracts against the parties or to seek any remedy thereunder, either directly or on behalf of the Fund. Nothing in the previous sentence should be read to suggest any waiver of any rights under federal or state securities laws.

The Investment Manager, which also serves as the Fund's administrator (the Administrator), Columbia Management, which serves as the Fund's sub-administrator pursuant to an agreement with the Investment Manager (the Sub-Administrator), the Distributor, and the Transfer Agent are all affiliates of Ameriprise Financial. They and their affiliates currently provide key services, including investment advisory, administration, distribution, shareholder servicing and transfer agency services, to the Fund and various other funds, including the Columbia Funds, and are paid for providing these services. These service relationships are described below.

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The Investment Manager

Columbia Wanger Asset Management, LLC is located at 71 S. Wacker Drive, Suite 2500, Chicago, Illinois 60606. As of March 31, 2022, the Investment Manager had assets under management of approximately $9.2 billion. The Investment Manager is a registered investment adviser and wholly-owned subsidiary of Columbia Management, which is a wholly-owned subsidiary of Ameriprise Financial. In addition to serving as an investment adviser to mutual funds, the Investment Manager acts as an investment manager for other private funds and institutional accounts.

Subject to oversight by the Board, the Investment Manager manages the day-to-day operations of the Fund, determining what securities and other investments the Fund should buy or sell and executing portfolio transactions. The Investment Manager may use the research and other capabilities of its affiliates and third parties in managing the Fund’s investments.

The Fund pays the Investment Manager a fee for its investment advisory services. The fee is calculated as a percentage of the daily net assets of the Fund and is paid monthly. For the Fund’s most recent fiscal year, aggregate fees paid to the Investment Manager by the Fund amounted to 1.09% of average daily net assets of the Fund, before any applicable reimbursements.

A discussion regarding the basis for the Board’s approval of the renewal of the Fund’s investment management services agreement with the Investment Manager is available in the Fund’s annual report to shareholders for the fiscal year ended December 31, 2021.

The Investment Manager and its investment advisory affiliates, including Columbia Management (Affiliates), around the world may coordinate in providing services to their clients. From time to time, the Investment Manager may engage its Affiliates to provide a variety of services such as investment research, investment monitoring, trading, and discretionary investment management (including portfolio management and proxy voting) to certain accounts managed by the Investment Manager, including the Fund. These Affiliates will provide services to the Fund and other accounts of the Investment Manager either pursuant to delegation agreements, personnel-sharing agreements or similar inter-company or other arrangements or relationships and the Fund will pay no additional fees and expenses as a result of any such arrangements or relationships. These Affiliates, like the Investment Manager, are direct or indirect subsidiaries of Ameriprise Financial and are registered with the appropriate respective regulators and, where required, the SEC and the Commodity Futures Trading Commission in the United States.

Pursuant to some of these arrangements or relationships, certain personnel of Columbia Management and other Affiliates may serve as “associated persons” or officers of the Investment Manager and, in this capacity, subject to the oversight and supervision of the Investment Manager and consistent with the investment objectives, policies and limitations set forth in this prospectus and the Fund's SAI, and with the Investment Manager’s and the Funds’ compliance policies and procedures, may provide such services to the Fund.

Portfolio Managers

Information about the portfolio managers primarily responsible for overseeing the Fund’s investments is shown below. The SAI provides additional information about the portfolio managers, including information relating to compensation, other accounts managed by the portfolio managers, and ownership by the portfolio managers of Fund shares.

Portfolio Management	Title	Role with Fund	Service with the Fund Since
Stephen Kusmierczak, CFA	International Team Head, Portfolio Manager and Analyst	Portfolio Manager or Co-Portfolio Manager since inception in 2011	2011
Sebastien Pigeon, CFA	Portfolio Manager and Analyst	Co-Portfolio Manager since 2021	2015

Mr. Kusmierczak has been associated with the Investment Manager or its predecessors as an investment professional since 2001, has been President or Co-President of the Trust since 2020, and was a Vice President of the Trust from 2011-2020. Mr. Kusmierczak began his investment career in 1999 and earned a B.A. from Bowdoin College and an M.P.A. from the Princeton School of Public and International Affairs.

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Mr. Pigeon has been associated with the Investment Manager as an investment professional since 2015 and has been a Vice President of the Trust since 2021. Mr. Pigeon began his investment career in 1997 and earned a B.A. from the Political Institute of Lyon and an M.B.A. from the KEDGE Business School.

The Administrator

Columbia Wanger Asset Management, LLC is responsible for overseeing the administrative operations of the Fund, including the general supervision of the Fund’s operations, coordination of the Fund’s service providers, and the provision of office facilities and related clerical and administrative services. The Administrator retains the Sub-Administrator to perform many of these services (including fund accounting), and pays a fee for the services of the Sub-Administrator. The Fund pays the Administrator a fee for its services, plus certain out-of-pocket expenses. The fee is calculated as an annual percentage of the Trust’s aggregate average daily net assets and is paid monthly, as follows:

Annual Administration Fee, as a % of Aggregate Daily Net Assets of the Trust:
Up to $8 billion	0.050%
$8 billion to $16 billion	0.040%
$16 billion to $35 billion	0.030%
$35 billion to $45 billion	0.025%
$45 billion and over	0.015%

The Distributor

Shares of the Fund are distributed by Columbia Management Investment Distributors, Inc., which is located at 290 Congress Street, Boston, MA 02210. The Distributor is a registered broker-dealer and an indirect, wholly-owned subsidiary of Ameriprise Financial. The Distributor and its affiliates may pay commissions, distribution and service fees and/or other compensation to entities, including Ameriprise Financial affiliates, for selling shares and providing services to investors.

The Transfer Agent

Columbia Management Investment Services Corp. is a registered transfer agent and wholly-owned subsidiary of Ameriprise Financial. The Transfer Agent is located at 290 Congress Street, Boston, MA 02210, and its responsibilities include processing purchases, redemptions and exchanges of Fund shares, calculating and paying distributions, maintaining shareholder records, preparing account statements and providing customer service. The Transfer Agent has engaged DST Asset Manager Solutions, Inc. to provide various shareholder or “sub-transfer agency” services. In addition, the Transfer Agent enters into agreements with various financial intermediaries through which you may hold Fund shares, pursuant to which the Transfer Agent pays these financial intermediaries for providing certain shareholder services. Depending on the type of account, the Fund pays the Transfer Agent a per account fee for each open account and compensates the Transfer Agent for certain out-of-pocket expenses, including certain payments to financial intermediaries through which shares are held. In addition, subject to certain limitations, the Fund compensates the Transfer Agent for payments made to financial intermediaries for the shareholder services that the intermediaries provide, in amounts that vary by share class and with the type of intermediary and the type of shareholder services provided. The Transfer Agent is contractually obligated to oversee such intermediaries for the purpose of reasonably assuring their compliance with applicable law and the terms of their agreements to provide the shareholder services. For more information about Shareholder Services fees, see Choosing a Share Class — Financial Intermediary Compensation.

Other Roles and Relationships of Ameriprise Financial and its Affiliates — Certain Conflicts of Interest

This section describes certain actual and potential conflicts of interest that arise from the financial services activities of Ameriprise Financial and its affiliates. Ameriprise Financial is a major financial services company, engaged in a broad range of financial activities beyond the fund-related activities of the Investment Manager, including: insurance,

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broker-dealer (sales and trading), asset management and financial services. As a consequence of these activities, Ameriprise Financial or its affiliates may have interests arising from their other business lines that conflict with the interests of the Fund. These activities may also, from time to time, place certain investment constraints on the management of the Fund that might not otherwise arise.

As described in More Information About the Fund - Primary Service Provider Contracts, the Investment Manager, Administrator, Sub-Administrator, Distributor and Transfer Agent are all affiliates of Ameriprise Financial. In addition to the services that they provide to the Fund, they also provide substantially similar services (for which they are compensated) to other clients and customers, including the Columbia Funds. Ameriprise Financial and its other affiliates may also provide services (for which they are compensated) to the Fund, other Columbia Funds or other clients and customers.

Examples of activities that could lead to conflicts of interest and/or impose limitations that could affect the Fund include the following:

■ the Investment Manager and other Ameriprise Financial affiliates may receive compensation and other benefits related to the management/administration of the Fund and the other Columbia Funds and the sale of their shares;

■ there may be competition for limited investment opportunities that must be allocated among the Fund, the other Columbia Funds and other clients and customers of the Investment Manager (which can include affiliates of the Investment Manager) that may have the same or similar investment objectives as the Fund;

■ management of the Fund may diverge from other Columbia Funds or other clients and customers of the Investment Manager or Ameriprise Financial affiliates, for example, advice given to the Fund may differ from, or conflict with, advice given to other funds or accounts;

■ there may be regulatory or investment restrictions imposed on the investment activities of the Investment Manager arising from the activities or holdings of other Columbia Funds or other clients or customers of the Investment Manager or Ameriprise Financial and its affiliates, for example, caps on the aggregate amount of certain types of investments or in holdings of particular portfolio companies that may be made by affiliated entities, including the Fund;

■ Ameriprise Financial or its affiliates may have potentially conflicting relationships with companies and other entities in which the Fund invests; and

■ there may be regulatory and other restrictions relating to the sharing of information between Ameriprise Financial and its affiliates, including the Investment Manager, for example, if an affiliated entity were in possession of non-public information, the Investment Manager might be prohibited by law from using that information in connection with the management of the Fund.

The Investment Manager and Ameriprise Financial have adopted various policies and procedures that are intended to identify, monitor and address conflicts of interest. However, there is no absolute assurance that these policies, procedures and disclosures will be effective.

Additional information about Ameriprise Financial and the types of conflicts of interest and other matters referenced above is set forth in the Investment Advisory and Other Services – Other Roles and Relationships of Ameriprise Financial and Affiliates – Certain Conflicts of Interest section of the SAI. Investors in the Fund should carefully review these disclosures and consult with their financial advisor if they have any questions.

Certain Legal Matters

Ameriprise Financial and certain of its affiliates are involved in the normal course of business in legal proceedings which include regulatory inquiries, arbitration and litigation, including class actions concerning matters arising in connection with the conduct of its activities as a diversified financial services firm. Ameriprise Financial believes that the Fund is not currently the subject of, and that neither Ameriprise Financial nor any of its affiliates are the subject of, any pending legal, arbitration or regulatory proceedings that are likely to have a material adverse effect on the Fund or the ability of Ameriprise Financial or its affiliates to perform under their contracts with the Fund. Information regarding certain pending and settled legal proceedings may be found in the Fund’s shareholder reports and in the

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SAI. Additionally, Ameriprise Financial is required to make quarterly (10-Q), annual (10-K) and, as necessary, 8-K filings with the SEC on legal and regulatory matters that relate to Ameriprise Financial and its affiliates. Copies of these filings may be obtained by accessing the SEC website at sec.gov.

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Choosing a Share Class

The Funds

The Columbia Acorn Funds and the other Columbia Funds generally share the same policies and procedures for investor services, as described below. Together, the Fund and the other Columbia Acorn Funds, along with the Columbia Funds, are referred to herein as the Funds.

Funds Contact Information

Additional information about the Funds, including sales charges and other class features and policies, can be obtained, free of charge, at columbiathreadneedleus.com,* by calling toll-free 800.345.6611, or by writing (regular mail) to Columbia Management Investment Services Corp., P.O. Box 219104, Kansas City, MO 64121-9104 or (express mail) Columbia Management Investment Services Corp., c/o DST Asset Manager Solutions, Inc., 430 W 7^th Street, Ste 219104, Kansas City, MO 64105-1407.

* The website references in this prospectus are inactive links and information contained in or otherwise accessible through the referenced websites does not form a part of this prospectus.

 FUNDamentals

Financial Intermediaries

The term “financial intermediary” refers to the selling and servicing agents that are authorized to sell and/or service shares of the Funds. Financial intermediaries include broker-dealers and financial advisors as well as firms that employ broker-dealers and financial advisors, including, for example, brokerage firms, banks, investment advisers, third party administrators and other firms in the financial services industry.

Omnibus Accounts

The term “omnibus account” refers to a financial intermediary’s account with the Fund (held directly through the Transfer Agent) that represents the combined holdings of, and transactions in, Fund shares of one or more clients of the financial intermediary (beneficial Fund shareholders). Omnibus accounts are held in the name of the financial intermediaries and not in the name of the beneficial Fund shareholders invested in the Fund through omnibus accounts.

Retirement Plans and Omnibus Retirement Plans

The term “retirement plan” refers to retirement plans created under Sections 401(a), 401(k), 457 and 403(b) of the Internal Revenue Code of 1986, as amended (the Code), and non-qualified deferred compensation plans governed by Section 409A of the Code and similar plans, but does not refer to individual retirement plans, such as traditional IRAs and Roth IRAs. The term “omnibus retirement plan” refers to a retirement plan that has a plan-level or omnibus account with the Transfer Agent.

Networked Accounts

Networking, offered by the Depository Trust & Clearing Corporation’s Wealth Management Services (WMS), is the industry standard IT system for mutual fund account reconciliation and dividend processing.

Summary of Share Class Features

Each share class has its own investment eligibility criteria, cost structure and other features. You may not be eligible to invest in every share class. Your financial intermediary may not make every share class available or may cease to make available one or more share classes of the Fund. The share class you select through your financial intermediary may have higher fees and/or sales charges than other classes of shares available through other financial intermediaries. An investor transacting in a class of Fund shares without any front-end sales charge, contingent deferred sales charge (CDSC), or other asset-based fee for sales or distribution, such as a Rule 12b-1 fee, may be required to pay a commission to the financial intermediary for effecting such transactions. Each investor’s personal situation is different and you may wish to discuss with your financial intermediary the share classes the Fund offers, which share classes are available to you and which share class(es) is/are appropriate for you. In all instances, it is your responsibility to notify your financial intermediary or (for Direct-at-Fund Accounts, as

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defined below) the Fund at the time of purchase of any relationship or other facts that may qualify you for sales charge waivers or discounts. The Fund, the Distributor and the Transfer Agent do not provide investment advice or make recommendations regarding Fund share classes. Your financial intermediary may provide advice and recommendations to you, such as which share class(es) is/are appropriate for you.

When deciding which class of shares to buy, you should consider, among other things:

■ The amount you plan to invest.

■ How long you intend to remain invested in the Fund.

■ The fees (e.g., sales charge or “load”) and expenses for each share class.

■ Whether you may be eligible for a reduction or waiver of sales charges when you buy or sell shares.

 FUNDamentals

Front-End Sales Charge Calculation

The front-end sales charge is calculated as a percentage of the offering price.

■ The net asset value (NAV) per share is the price of a share calculated by the Fund every business day.

■ The offering price per share is the NAV per share plus any front-end sales charge (or load) that applies.

The dollar amount of any applicable front-end sales charge is the difference between the offering price of the shares you buy and the NAV of those shares. To determine the front-end sales charge you will pay when you buy Class A shares, the Fund will add the amount of your investment to the value of your account (and any other accounts eligible for aggregation of which you or your financial intermediary notifies the Fund) and base the sales charge on the aggregate amount. For information on account value aggregation, sales charge waivers and other important information, see Choosing a Share Class — Reductions/Waivers of Sales Charges.

 FUNDamentals

Contingent Deferred Sales Charge

A contingent deferred sales charge (CDSC) is a sales charge applied at the time you sell your shares, unlike a front-end sales charge that is applied at the time of purchase. A CDSC can vary based on the length of time that you have held your shares. A CDSC is applied to the NAV at the time of your purchase or sale, whichever is lower, and will not be applied to any shares you receive through Fund distribution reinvestments or any amount that represents appreciation in the value of your shares. For purposes of calculating a CDSC, the start of the holding period is generally the first day of the month in which your purchase was made.

When you place an order to sell shares of a class that has a CDSC, the Fund will first redeem any shares that are not subject to a CDSC, followed by those you have held the longest. This means that if a CDSC is imposed, you cannot designate the individual shares being redeemed for U.S. federal income tax purposes. You should consult your tax advisor about the tax consequences of investing in the Fund. In certain circumstances, the CDSC may not apply. See Choosing a Share Class — Reductions/Waivers of Sales Charges for details.

Share Class Features

The following summarizes the primary features of Class A, Class Adv, Class C, Class Inst, Class Inst2, Class Inst3, and Class R shares.

Not all Funds offer every class of shares. The Fund offers the class(es) of shares set forth on the cover of this prospectus and may offer other share classes through a separate prospectus. Although certain share classes are generally closed to new and/or existing investors, information relating to these share classes is included in the table below because certain qualifying purchase orders are permitted, as described below.

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The sales charge reductions and waivers available to investors who purchase and hold their Fund shares through different financial intermediaries may vary. Appendix A describes financial intermediary-specific reductions and/or waiver policies. A shareholder transacting in Fund shares through a financial intermediary identified in Appendix A should carefully read the terms and conditions of Appendix A. A reduction and/or waiver that is specific to a particular financial intermediary is not available to Direct-at-Fund Accounts, as defined below, or through another financial intermediary. The information in Appendix A may be provided by, or compiled from or based on information provided by the financial intermediaries identified in Appendix A. To obtain additional information regarding any sales charge reduction and/or waiver described in Appendix A, and to ensure that you receive any such reductions or waivers that may be available to you, please consult your financial intermediary.

Share Class	Eligible Investors; Minimum Initial Investments; Conversion Features(a)	Front-End Sales Charges(b)	Contingent Deferred Sales Charges (CDSCs)(b)	Sales Charge Reductions/Waivers	Maximum Distribution and/or Service (12b-1) Fees(c)
Class A	Eligibility: Available to the general public for investment Minimum Initial Investment: $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts (as described below))	5.75% maximum, declining to 0.00% on investments of $1 million or more	CDSC on certain investments of between $1 million and $50 million redeemed within 18 months after purchase charged as follows: • 1.00% CDSC if redeemed within 12 months after purchase and • 0.50% CDSC if redeemed more than 12, but less than 18, months after purchase	Reductions: yes, see Choosing a Share Class — Reductions/Waivers of Sales Charges – Class A Shares Front-End Sales Charge Reductions Waivers: yes, on Fund distribution reinvestments. For additional waivers, see Choosing a Share Class — Reductions/Waivers of Sales Charges – Class A Shares Front-End Sales Charge Waivers, as well as Choosing a Share Class — CDSC Waivers – Class A and Class C Financial intermediary-specific waivers are also available, see Appendix A	Service Fee: 0.25%
Class Adv	Eligibility: Available only to (i) omnibus retirement plans, including self-directed brokerage accounts within omnibus retirement plans that clear through institutional no transaction fee (NTF) platforms; retirement plans; (ii) trust companies or similar institutions; (iii) broker-dealers, banks, trust companies and similar institutions that clear Fund share transactions for their client or customer investment advisory or similar accounts through designated financial intermediaries and their mutual fund trading platforms that have been granted specific written authorization from the Transfer Agent with respect to Class Adv eligibility apart from selling, servicing or similar agreements; (iv) 501(c)(3) charitable organizations; (v) 529 plans; (vi) health savings accounts; (vii) investors participating in a fee-based advisory program sponsored by a financial intermediary or other entity that is not compensated by the Fund for those services, other than payments for shareholder servicing or sub-accounting performed in place	None	None	N/A	None

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Share Class	Eligible Investors; Minimum Initial Investments; Conversion Features(a)	Front-End Sales Charges(b)	Contingent Deferred Sales Charges (CDSCs)(b)	Sales Charge Reductions/Waivers	Maximum Distribution and/or Service (12b-1) Fees(c)
	of the Transfer Agent; and (viii) commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Adv shares within such platform. Minimum Initial Investment: None, except in the case of (viii) above, which is $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts)
Class C	Eligibility: Available to the general public for investment Minimum Initial Investment: $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts) Conversion Feature: Yes. Effective April 1, 2021, Class C shares generally automatically convert to Class A shares of the same Fund in the month of or the month following the 8-year anniversary of the Class C shares purchase date. Prior to April 1, 2021, Class C shares generally automatically converted to Class A shares of the same Fund in the month of or the month following the 10-year anniversary of the Class C shares purchase date.(a)	None	1.00% on certain investments redeemed within one year of purchase	Waivers: yes, on Fund distribution reinvestments. For additional waivers, see Choosing a Share Class — CDSC Waivers – Class A and Class C Financial intermediary-specific CDSC waivers are also available, see Appendix A	Distribution Fee: 0.75% Service Fee: 0.25%
Class Inst	Eligibility: Available only to certain eligible investors, which are subject to different minimum investment requirements, ranging from $0 to $2,000, including investors who purchase Fund shares through commissionable brokerage platforms where the financial intermediary holds the shares in an omnibus account and, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst shares within such platform; closed to (i) accounts of financial intermediaries that clear Fund share transactions for their client or customer accounts through designated financial intermediaries and their mutual fund	None	None	N/A	None

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Share Class	Eligible Investors; Minimum Initial Investments; Conversion Features(a)	Front-End Sales Charges(b)	Contingent Deferred Sales Charges (CDSCs)(b)	Sales Charge Reductions/Waivers	Maximum Distribution and/or Service (12b-1) Fees(c)
	trading platforms that have been given specific written notice from the Transfer Agent of the termination of their eligibility for new purchases of Class Inst shares and (ii) omnibus group retirement plans, subject to certain exceptions(d) Minimum Initial Investment: See Eligibility above
Class Inst2	Eligibility: Available only to (i) certain registered investment advisers and family offices that clear Fund share transactions for their client or customer accounts through designated financial intermediaries and their mutual fund trading platforms that have been granted specific written authorization from the Transfer Agent with respect to Class Inst2 eligibility apart from selling, servicing or similar agreements; (ii) omnibus retirement plans(d); (iii) health savings accounts, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst2 shares within such platform and that Fund shares are held in an omnibus account; and (iv) institutional investors that are clients of the Columbia Threadneedle Global Institutional Distribution Team that invest in Class Inst2 shares for their own account through platforms approved by the Distributor or an affiliate thereof to offer and/or service Class Inst2 shares within such platform. Minimum Initial Investment: None	None	None	N/A	None
Class Inst3	Eligibility: Available to: (i) group retirement plans that maintain plan-level or omnibus accounts with the Fund(d); (ii) institutional investors that are clients of the Columbia Threadneedle Global Institutional Distribution Team that invest in Class Inst3 shares for their own account through platforms approved by the Distributor or an affiliate thereof to offer and/or service Class Inst3 shares within such platform; (iii) collective trust funds; (iv) affiliated or unaffiliated mutual funds (e.g., funds operating as funds-of-funds); (v) fee-based platforms of financial intermediaries (or the clearing intermediary they trade through) that have an agreement with the	None	None	N/A	None

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Share Class	Eligible Investors; Minimum Initial Investments; Conversion Features(a)	Front-End Sales Charges(b)	Contingent Deferred Sales Charges (CDSCs)(b)	Sales Charge Reductions/Waivers	Maximum Distribution and/or Service (12b-1) Fees(c)
	Distributor or an affiliate thereof that specifically authorizes the financial intermediary to offer and/or service Class Inst3 shares within such platform, provided also that Fund shares are held in an omnibus account; (vi) commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst3 shares within such platform and that Fund shares are held in an omnibus account; (vii) health savings accounts, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst3 shares within such platform and that Fund shares are held in an omnibus account; and (viii) bank trust departments, subject to an agreement with the Distributor that specifically authorizes offering Class Inst3 shares and provided that Fund shares are held in an omnibus account. In each case above where noted that Fund shares are required to be held in an omnibus account, the Distributor, may, in its discretion, determine to waive this requirement. Minimum Initial Investment: No minimum for the eligible investors described in (i), (iii), (iv) and (v) above; $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts) for the eligible investors described in (vi) above; and $1 million for all other eligible investors, unless waived in the discretion of the Distributor
Class R	Eligibility: Available only to eligible retirement plans, health savings accounts and, in the sole discretion of the Distributor, other types of retirement accounts held through platforms maintained by financial intermediaries approved by the Distributor Minimum Initial Investment: None	None	None	N/A	Distribution Fee: 0.50%

(a) For more information on the conversion of Class C shares to Class A shares, see Choosing a Share Class — Sales Charges and Commissions — Class C Shares —Conversion to Class A Shares.

(b) For more information on applicable sales charges, see Choosing a Share Class — Sales Charges and Commissions, and for information about certain exceptions to these sales charges, see Choosing a Share Class — Reductions/Waivers of Sales Charges.

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(c) These are the maximum applicable distribution and/or service fees under the Fund’s Rule 12b-1 plan. Because these fees are paid out of Fund assets on an ongoing basis, over time these fees will increase the cost of your investment and may cost you more than paying other types of distribution and/or service fees. For more information on distribution and service fees, see Choosing a Share Class — Distribution and Service Fees.

(d) These share classes are closed to new accounts generally or to new accounts of certain categories of investors, subject to certain conditions, as summarized below and described in more detail under Buying, Selling and Exchanging Shares — Buying Shares — Eligible Investors:

•  Class Inst Shares: Financial intermediaries that clear Fund share transactions through designated financial intermediaries and their mutual fund trading platforms that were given specific written notice from the Transfer Agent of the termination, effective March 29, 2013, of their eligibility for new purchases of Class Inst shares and omnibus retirement plans are not permitted to establish new Class Inst accounts, subject to certain exceptions. Omnibus retirement plans that opened and, subject to exceptions, funded a Class Inst account as of close of business on March 28, 2013, and have continuously held Class Inst shares in such account after such date, may generally continue to make additional purchases of Class Inst shares, open new Class Inst accounts and add new participants. In certain circumstances and in the sole discretion of the Distributor, omnibus retirement plans affiliated with a grandfathered plan may also open new Class Inst accounts. Accounts of financial intermediaries (other than omnibus retirement plans) that clear Fund share transactions for their client or customer accounts through designated financial intermediaries and their mutual fund trading platforms are not permitted to establish new Class Inst accounts or make additional purchases of Class Inst shares (other than through reinvestment of distributions).

•  Class Inst2 Shares. Shareholders with Class Inst2 accounts funded before November 8, 2012 who do not satisfy the current eligibility criteria for Class Inst2 shares may not establish new Class Inst2 accounts but may continue to make additional purchases of Class Inst2 shares in existing accounts. In addition, investment advisory programs and similar programs that opened a Class Inst2 account as of May 1, 2010, and continuously hold Class Inst2 shares in such account after such date, may generally not only continue to make additional purchases of Class Inst2 shares but also open new Class Inst2 accounts and add new shareholders in the program.

•  Class Inst3 Shares: Shareholders with Class Inst3 accounts funded before November 8, 2012 who do not satisfy the current eligibility criteria for Class Inst3 shares may not establish new accounts for such share class but may continue to make additional purchases of Class Inst3 shares in existing accounts.

Sales Charges and Commissions

Sales charges, commissions, and distribution fees compensate financial intermediaries (typically your financial advisor) for selling shares to you, and service fees compensate financial intermediaries for maintaining and servicing the shares held in your account with them. Distribution and service fees are discussed in a separate sub-section below. Depending on which share class you choose and the financial intermediary through which you purchase your shares, you may pay these charges at potentially different levels at the outset as a front-end sales charge, at the time you sell your shares as a CDSC and/or over time in the form of distribution and/or service fees. You may be required to pay brokerage commissions and other fees to financial intermediaries when transacting in any class of Fund shares, including those that do not assess any front-end sales charge, contingent deferred sales charge, or other asset-based fee for sales or distribution. Such brokerage commissions and other fees are set by the financial intermediary.

As described in more detail below, Class A shares have a front-end sales charge, which is deducted from your purchase price when you buy your shares, and results in a smaller dollar amount being invested in the Fund than the purchase price you pay (unless you qualify for a waiver or reduction of the sales charge). The Fund’s other share classes do not have a front-end sales charge, so the full amount of your purchase price is invested in those classes. Class A shares have lower ongoing distribution and/or service fees than Class C and Class R shares of the Fund. Over time, Class C and Class R shares can incur distribution and/or service fees that are equal to or more than the front-end sales charge and the distribution and/or service fees you would pay for Class A shares. Although the full amount of your purchase price of Class C and Class R shares is invested in a Fund, your return on this money will be reduced by the expected higher annual expenses of Class C and Class R shares. In this regard, note that effective April 1, 2021, Class C shares will generally automatically convert to Class A shares of the same Fund in the month of or the month following the 8-year anniversary of the Class C shares purchase date (prior to April 1, 2021, the 10-year anniversary of such date). The Fund may convert Class C shares held through a financial intermediary to Class A shares sooner in connection with the withdrawal of Class C shares of the Fund from the financial intermediary’s platform or accounts. No sales charge or other charges will apply in connection with such conversions, and the conversions are free from U.S. federal income tax. Once your Class C shares convert to Class A shares, your total returns from an investment in the Fund may increase as a result of the lower operating costs of Class A shares. Class Adv, Class Inst, Class Inst2 and Class Inst3 shares of the Fund do not have distribution and/or service fees.

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Whether the ultimate cost is higher for one share class over another depends on the amount you invest, how long you hold your shares, the fees (i.e., sales charges) and expenses of the class and whether you are eligible for reduced or waived sales charges, if available. You are responsible for choosing the share class most appropriate for you after taking into account your share class eligibility, class-specific features, and any applicable reductions in, or waivers of, sales charges. For more information, see Choosing a Share Class – Reductions/Waivers of Sales Charges. We encourage you to consult with a financial advisor who can help you with your investment decisions. Please contact your financial intermediary for more information about services, fees and expenses, and other important information about investing in the Fund, as well as with any questions you may have about your investing options. In all instances, it is your responsibility to notify your financial intermediary or (for Direct-at-Fund Accounts, as defined below) the Fund at the time of purchase of any relationship or other facts that may qualify you for sales charge waivers or discounts.

Class A Shares — Front-End Sales Charge

Unless your purchase qualifies for a waiver (e.g., you buy the shares through reinvested Fund dividends or distributions or subject to an applicable financial intermediary-specific waiver), you will pay a front-end sales charge when you buy Class A shares, resulting in a smaller dollar amount being invested in a Fund than the purchase price you pay. The Class A shares sales charge is waived on Class C shares converted to Class A shares. For more information about sales charge waivers and reduction opportunities, see Choosing a Share Class — Reductions/Waivers of Sales Charges and Appendix A.

The Distributor receives the sales charge and re-allows (or pays) a portion of the sales charge to the financial intermediary through which you purchased the shares. The Distributor retains the balance of the sales charge.

The front-end sales charge you will pay on Class A shares:

■ depends on the amount you are investing (generally, the larger the investment, the smaller the percentage sales charge), and

■ is based on the total amount of your purchase and the value of your account (and any other accounts eligible for aggregation of which you or your financial intermediary notifies the Fund).

The table below presents the front-end sales charge as a percentage of both the offering price and the net amount invested.

Class A Shares — Front-End Sales Charge — Breakpoint Schedule
Breakpoint Schedule For:	Dollar amount of shares bought(a)	Sales charge as a % of the offering price(b)	Sales charge as a % of the net amount invested(b)	Amount retained by or paid to financial intermediaries as a % of the offering price
Class A Shares	$0–$49,999	5.75%	6.10%	5.00%
	$50,000–$99,999	4.50%	4.71%	3.75%
	$100,000–$249,999	3.50%	3.63%	3.00%
	$250,000–$499,999	2.50%	2.56%	2.15%
	$500,000–$999,999	2.00%	2.04%	1.75%
	$1,000,000 or more	0.00%	0.00%	0.00%(c)

(a) Purchase amounts and account values may be aggregated among all eligible Fund accounts for the purposes of this table. See Choosing a Share Class — Reductions/Waivers of Sales Charges for a discussion of account value aggregation.

(b) Because the offering price is calculated to two decimal places, the dollar amount of the sales charge as a percentage of the offering price and your net amount invested for any particular purchase of Fund shares may be higher or lower depending on whether downward or upward rounding was required during the calculation process. Purchase price includes the sales charge.

(c) For information regarding cumulative commissions paid to your financial intermediary when you buy $1 million or more of Class A shares of a Fund, see Class A Shares — Commissions below.

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Class A Shares — CDSC

In some cases, you'll pay a CDSC if you sell Class A shares that you purchased without a front-end sales charge.

■ If you purchased Class A shares without an initial sales charge because your accounts aggregated between $1 million and $50 million at the time of purchase, you will incur a CDSC if you redeem those shares within 18 months after purchase, which is charged as follows: 1.00% CDSC if shares are redeemed within 12 months after purchase; and 0.50% CDSC if shares are redeemed more than 12, but less than 18, months after purchase.

■ Subsequent Class A share purchases that bring your aggregate account value to $1 million or more (but less than $50 million) will also be subject to a CDSC if you redeem them within the time periods noted above.

Class A Shares — Commissions

The Distributor may pay your financial intermediary an up-front commission when you buy Class A shares. The Distributor generally funds the commission through the applicable sales charge you paid. For more information, see Class A Shares — Front-End Sales Charge above.

The Distributor may also pay your financial intermediary a cumulative commission when you buy Class A shares in amounts not subject to a front-end sales charge, according to the following schedules (assets initially purchased into Class A shares of Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund and Columbia U.S. Treasury Index Fund that were purchased without the application of a front-end sales charge are excluded for purposes of calculating a financial intermediary’s commission under these schedules):

Class A Shares — Commission Schedule (Paid by the Distributor to Financial Intermediaries)
Purchase Amount	Commission Level* (as a % of net asset value per share)
$1 million – $2,999,999	1.00%
$3 million – $49,999,999	0.50%
$50 million or more	0.25%

* The commission level applies to the applicable asset level; therefore, for example, for a purchase of $5 million, the Distributor would pay a commission of 1.00% on the first $2,999,999 and 0.50% on the balance.

Class C Shares — Front-End Sales Charge

You do not pay a front-end sales charge when you buy Class C shares, but you may pay a CDSC when you sell Class C shares. Although Class C shares do not have a front-end sales charge, over time Class C shares can incur distribution and/or service fees that are equal to or more than the front-end sales charge and distribution and/or service fees you would pay for Class A shares. Thus, although the full amount of your purchase of Class C shares is invested in a Fund, any positive investment return on this money may be partially or fully offset by the expected higher annual expenses of Class C shares.

Class C Shares — Conversion to Class A Shares

Effective April 1, 2021, Class C shares of a Fund generally automatically convert to Class A shares of the same Fund in the month of or the month following the 8-year anniversary of the Class C shares purchase date. Prior to April 1, 2021, Class C shares of a Fund generally automatically converted to Class A shares of the same Fund in the month of or in the month following the 10-year anniversary of the Class C shares purchase date. Class C shares held through a financial intermediary in an omnibus account will be converted (pursuant to the financial intermediary’s Class C conversion policy, including those disclosed in Appendix A, which may differ from the Fund’s policy described here) provided that the intermediary is able to track individual shareholders’ holding periods. It is the financial intermediary's (and not the Fund's) responsibility to keep records and to ensure that the shareholder holding period is calculated properly. Not all financial intermediaries are able to track individual shareholders' holding periods. For example, group retirement plans held through third-party intermediaries that hold Class C shares in an omnibus account may not track participant level share lot aging. Please consult with your financial intermediary about your

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eligibility for Class C share conversion. The Fund may convert Class C shares held through a financial intermediary to Class A shares sooner in connection with the withdrawal of Class C shares of the Fund from the financial intermediary's platform or accounts. Once your Class C shares convert to Class A shares, your total returns from an investment in the Fund may increase as a result of the lower operating costs of Class A shares.

The following rules apply to the automatic conversion of Class C shares to Class A shares:

■ Class C share accounts that are Direct-at-Fund Accounts and Networked Accounts for which the Transfer Agent (and not your financial intermediary) sends you Fund account transaction confirmations and statements, convert on or about the 15th day of the month (if the 15th is not a business day, then the next business day thereafter) that they become eligible for automatic conversion provided that the Fund has records that Class C shares have been held for the requisite time period.

■ For purposes of determining the month when your Class C shares are eligible for conversion, the start of the holding period is the first day of the month in which your purchase was made. Your financial intermediary may choose a different day of the month to convert Class C shares. Please contact your financial intermediary for more information on calculating the holding period.

■ Any shares you received from reinvested distributions on these shares generally will convert to Class A shares at the same time.

■ You’ll receive the same dollar value of Class A shares as the Class C shares that were automatically converted. Class C shares that you received from an exchange of Class C shares of another Fund will convert based on the day you bought the original shares.

■ In addition to the above automatic conversion of Class C to Class A shares policy, the Transfer Agent seeks to convert Class C shares as soon as administratively feasible, regardless of how long such shares have been owned, to Class A shares of the same Fund for Direct-at-Fund Accounts (as defined below) that do not or no longer have a financial intermediary assigned to them. Direct-at-Fund Accounts that do not have a financial intermediary assigned to them are not permitted to purchase Class C shares; Class C share purchase orders received by Direct-at-Fund Accounts that do not have a financial intermediary assigned to the account will automatically be invested in Class A shares of the same Fund.

■ No sales charge or other charges apply in connection with these automatic conversions, and the conversions are free from U.S. federal income tax.

Class C Shares — CDSC

You will pay a CDSC of 1.00% if you redeem Class C shares within 12 months of buying them unless you qualify for a waiver of the CDSC (e.g., the shares you are selling were purchased with reinvested Fund distributions). Redemptions of Class C shares are not subject to a CDSC if redeemed after 12 months. For more information, see Choosing a Share Class — Reductions/Waivers of Sales Charges.

Class C Shares — Commissions

Although there is no front-end sales charge when you buy Class C shares, the Distributor makes an up-front payment (which includes a sales commission and an advance of service fees) directly to your financial intermediary of up to 1.00% of the NAV per share when you buy Class C shares. A portion of this payment may be passed along to your financial advisor. The Distributor seeks to recover this payment through distribution fees of up to 0.75% and shareholder service fees of up to 0.25% it receives under the Fund's Rule 12b-1 plan during the first 12 months following the sale of Class C shares, and any applicable CDSC when you sell your shares. For more information, see Choosing a Share Class — Distribution and Service Fees.

Reductions/Waivers of Sales Charges

The availability of certain sales charge waivers and discounts will depend on whether you purchase your shares directly from the Fund (i.e., a Direct-at-Fund Account, as defined below) or through a financial intermediary. Financial intermediaries may have different policies and procedures regarding the availability of front-end sales charge and/or CDSC waivers. In all instances, it is your responsibility to notify your financial intermediary or (for Direct-at-Fund

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Accounts, as defined below) the Fund at the time of purchase of any relationship or other facts that may qualify you for sales charge waivers or discounts. In order to obtain waivers and discounts not available through a particular financial intermediary, shareholders will have to purchase Fund shares directly from the Fund (if permitted) or through a different financial intermediary. For a description of financial intermediary-specific sales charge reductions and/or waivers, see Appendix A.

Class A Shares Front-End Sales Charge Reductions

The Fund makes available two means of reducing the front-end sales charge that you may pay when you buy Class A shares of a Fund. These types of sales charge reductions are also referred to as breakpoint discounts.

First, through the right of accumulation (ROA), you may combine the value of eligible accounts (as described in the Eligible Accounts section below) maintained by you and members of your immediate family to reach a breakpoint discount level and apply a lower front-end sales charge to your purchase. To calculate the combined value of your eligible Fund accounts in the particular class of shares, the Fund will use the current public offering price per share. For purposes of obtaining a breakpoint discount through ROA, you may aggregate your and your “immediate family” members' ownership (as described in the FUNDamentals box below) of certain classes of shares held in certain account types, as described in the Eligible Accounts section below.

Second, by making a statement of intent to purchase additional shares (commonly referred to as a letter of intent (LOI)), you may pay a lower sales charge on all purchases of Class A shares made within 13 months after the date of your LOI. Your LOI must state the aggregate amount of purchases you intend to make in that 13-month period, which must be at least enough to reach the first (or next) breakpoint of the Fund. The required form of LOI may vary by financial intermediary, so please contact them directly for more information. Five percent of the purchase commitment amount will be placed in escrow. At the end of the 13-month period, the shares will be released from escrow, provided that you have invested the commitment amount. If you do not invest the commitment amount by the end of the 13 months, the remaining amount of the unpaid sales charge will be redeemed from the escrowed shares and the remaining balance released from escrow. To calculate the total value of the purchases you've made under an LOI, the Fund will use the historic cost (i.e., dollars invested and not current market value) of the shares held in each eligible account; reinvested dividends or capital gains, or purchases made through the reinstatement privilege do not count as purchases made under an LOI. For purposes of making an LOI to purchase additional shares, you may aggregate eligible shares owned by you or your immediate family members in eligible accounts, valued as of the day immediately before the initiation of your LOI.

You must request the reduced sales charge (whether through ROA or an LOI) when you buy shares. If you do not complete and file an LOI, or do not request the reduced sales charge at the time of purchase, you will not be eligible for the reduced sales charge. To obtain a breakpoint discount, you must notify your financial intermediary in writing at the time you buy your shares of each eligible account maintained by you and members of your immediate family, including accounts maintained through different financial intermediaries. You and your financial intermediary are responsible for ensuring that you receive discounts for which you are eligible. Please contact your financial intermediary with questions regarding application of the eligible discount to your account. You may be asked by your financial intermediary (or by the Fund if you hold your account directly with the Fund) for account statements or other records to verify your discount eligibility for new and subsequent purchases, including, when applicable, records for accounts opened with a different financial intermediary and records of accounts established by members of your immediate family.

The sales charge reductions available to investors who purchase and hold their Fund shares through different financial intermediaries may vary. For a description of such financial intermediary-specific sales charge reductions, see Appendix A.

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 FUNDamentals

Your “Immediate Family” and Account Value Aggregation

For purposes of obtaining a breakpoint discount for Class A shares, the value of your account will be deemed to include the value of all applicable shares in eligible Fund accounts that are held by you and your “immediate family,” which includes your spouse, domestic partner, parent, step-parent, legal guardian, child under 21, step-child under 21, father-in-law and mother-in-law, provided that you and your immediate family members share the same mailing address. Any Fund accounts linked together for account value aggregation purposes as of the close of business on September 3, 2010 will be permitted to remain linked together. Group retirement plan accounts are valued at the retirement plan level.

Eligible Accounts

The following accounts are eligible for account value aggregation as described above, provided that they are invested in Class A (excluding, in the case of Direct-at-Fund Accounts, Funds that do not assess a front-end sales charge, including Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund and Columbia U.S. Treasury Index Fund, unless such shares were purchased via an exchange from Class A shares of a Fund on which you paid the Class A share applicable front-end sales charge), Class C, Class E, Class Inst or Class V shares of a Fund, or non-retirement plan accounts invested in Class Adv, Class Inst2 or Class Inst3 shares of a Fund: individual or joint accounts; Roth and traditional Individual Retirement Accounts (IRAs); Simplified Employee Pension accounts (SEPs), Savings Investment Match Plans for Employees of Small Employers accounts (SIMPLEs) and Tax Sheltered Custodial Accounts (TSCAs); Uniform Gifts to Minors Act (UGMA)/Uniform Transfers to Minors Act (UTMA) accounts for which you, your spouse, or your domestic partner is parent or guardian of the minor child; revocable trust accounts for which you or an immediate family member, individually, is the beneficial owner/grantor; accounts held in the name of your, your spouse’s, or your domestic partner’s sole proprietorship or single owner limited liability company or S corporation; qualified retirement plan assets, provided that you are the sole owner of the business sponsoring the plan, are the sole participant (other than a spouse) in the plan, and have no intention of adding participants to the plan; and investments in wrap accounts.

The following accounts are not eligible for account value aggregation as described above: accounts of pension and retirement plans with multiple participants, such as 401(k) plans (which are combined to reduce the sales charge for the entire pension or retirement plan and therefore are not used to reduce the sales charge for your individual accounts); investments in 529 plans, donor advised funds, variable annuities, variable insurance products or managed separate accounts; charitable and irrevocable trust accounts; accounts holding shares of money market funds that used the Columbia brand before May 1, 2010; accounts invested in Class R shares of a Fund; and retirement plan accounts invested in Class Adv, Class Inst2 or Class Inst3 shares of a Fund.

Additionally, direct purchases of shares of Columbia Government Money Market Fund may not be aggregated for account value aggregation purposes; however, shares of Columbia Government Money Market Fund acquired by exchange from other Columbia Funds that assess a sales charge may be included in account value aggregation.

Class A Shares Front-End Sales Charge Waivers

There are no front-end sales charges on reinvested Fund distributions. The Class A shares sales charge is waived on conversions of Class C shares to Class A shares. The Distributor may waive front-end sales charges on purchases of Class A shares of the Funds by certain categories of investors, including Board members, certain employees of financial intermediaries, Fund portfolio managers, certain partners and employees of outside legal counsel to the Funds or the Board, separate accounts of an insurance company exempt from registration as an investment company under Section 3(c)(11) of the 1940 Act, registered broker-dealer firms that have an agreement with the Distributor purchasing Fund shares for their investment account only, and qualified employee benefit plan rollovers to Class A

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Choosing a Share Class (continued)

shares in the same Fund (see Appendix S to the SAI for details). For a more complete description of categories of investors who may purchase Class A shares of the Funds at NAV, without payment of any front-end sales charge that would otherwise apply, see Appendix S to the SAI.

In addition, certain types of purchases of Class A shares may be made at NAV. The Distributor may waive front-end sales charges on (i) purchases (including exchanges) of Class A shares in accounts of financial intermediaries that have entered into agreements with the Distributor to offer Fund shares to self-directed investment brokerage accounts that may or may not charge a transaction fee to customers; (ii) exchanges of Class Inst shares of a Fund for Class A shares of the Fund; (iii) purchases of Class A shares on brokerage mutual fund-only platforms of financial intermediaries that have an agreement with the Distributor that specifically authorizes the offering of Class A shares within such platform; (iv) purchases through certain wrap fee or other products or programs that involve fee-based compensation arrangements that have, or clear trades through a financial intermediary that has, a selling agreement with the Distributor; (v) purchases through state sponsored 529 Plans; (vi) purchases through banks, trust companies, and thrift institutions acting as fiduciaries; (vii) purchases through certain employee benefit plans and certain qualified deferred compensation plans; and (viii) purchases of Class A shares in Direct-at-Fund Accounts (as defined below) that do not have a financial intermediary assigned to them. For a more complete description of these eligible transactions, see Appendix S to the SAI.

The sales charge waivers available to investors who purchase and hold their Fund shares through different financial intermediaries may vary. For a description of such financial intermediary-specific sales charge waivers, see Appendix A.

CDSC Waivers – Class A and Class C

You may be able to avoid an otherwise applicable CDSC when you sell Class A or Class C shares of the Fund. This could happen because of the way in which you originally invested in the Fund, because of your relationship with the Funds or for other reasons. For example, the CDSC will be waived on redemptions of shares: in the event of the shareholder's death; for which no sales commission or transaction fee was paid to an authorized financial intermediary at the time of purchase; purchased through reinvestment of dividends and capital gain distributions; that result from required minimum distributions taken from retirement accounts due to the shareholder reaching the qualified age based on applicable IRS regulations; that result from returns of excess contributions made to retirement plans or individual retirement accounts (subject to certain conditions); initially purchased by an employee benefit plan (for Class A shares) and that are not connected with a plan level termination (for Class C shares); in connection with the Fund's Small Account Policy (which is described in Buying, Selling and Exchanging Shares — Transaction Rules and Policies); held within Direct-at-Fund Accounts that do not have a financial intermediary assigned to them; and by certain other investors and in certain other types of transactions or situations. Restrictions may apply to certain accounts and certain transactions. The Distributor may, in its sole discretion, authorize the waiver of the CDSC for additional classes of investors. The Fund may change or cancel these terms at any time. Any change or cancellation applies only to future purchases. For a more complete description of the available waivers of the CDSC on redemptions of Class A or Class C shares, see Appendix S to the SAI.

The sales charge waivers available to investors who purchase and hold their Fund shares through different financial intermediaries may vary. For a description of such financial intermediary-specific sales charge waivers, see Appendix A.

Repurchases (Reinstatements)

As noted in the table below, you can redeem shares of certain classes (see Redeemed Share Class below) and use such redemption proceeds to buy shares of the Corresponding Repurchase Class without paying an otherwise applicable sales charge and/or CDSC (other than, in the case of Direct-at-Fund Accounts, redemptions from Funds that do not assess a front-end sales charge, including Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund and Columbia U.S. Treasury Index Fund, unless such shares were purchased via an exchange from Class A shares of a Fund on which you paid the Class A share applicable front-end sales charge) within 90 days, up to the amount of the redemption proceeds.

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Repurchases (Reinstatements)
Redeemed Share Class	Corresponding Repurchase Class
Class A	Class A
Class C	Class C

Any CDSC paid upon redemption of your Class A or Class C shares of a Fund will not be reimbursed.

To be eligible for the repurchase (or reinstatement) privilege, the purchase must be made into an account for the same owner, but does not need to be into the same Fund from which the shares were sold. The Transfer Agent, Distributor or their agents must receive a written reinstatement request from you or your financial intermediary within 90 days after the shares are redeemed. The purchase of the Corresponding Repurchase Class (as noted in the table above) through this repurchase (or reinstatement) privilege will be made at the NAV of such shares next calculated after the request is received in “good form.” Systematic withdrawals and purchases are excluded from this policy.

Restrictions and Changes in Terms and Conditions

Restrictions may apply to certain accounts and certain transactions. The Funds and/or the Distributor may change or cancel these terms and conditions at any time. Unless you provide your financial intermediary with information in writing about all of the factors that may count toward available reductions or waivers of an applicable sales charge, there can be no assurance that you will receive all of the reductions and waivers for which you may be eligible. To the extent your Fund account is held directly with the Fund, you should provide this information to the Fund when placing your purchase or redemption order. Please see Appendix A to this prospectus and Appendix S of the SAI for more information about sales charge waivers.

Distribution and Service Fees

The Board has approved, and the Columbia Acorn Funds have adopted, a distribution plan pursuant to Rule 12b-1 under the 1940 Act that sets the distribution and/or service fees that are periodically deducted from the Funds’ assets. These fees are calculated daily, may vary by share class and are intended to compensate the Distributor and/or eligible financial intermediaries for, with regard to distribution fees, selling Fund shares and, with regard to service fees, directly or indirectly providing services to shareholders. Because the fees are paid out of the Fund's assets on an ongoing basis, they will increase the cost of your investment over time.

The table below shows the maximum annual distribution and/or service fees (as an annual percentage of average daily net assets) and the combined amount of such fees applicable to each share class of the Columbia Acorn Funds:

	Distribution Fee	Service Fee	Combined Total
Class A	None	0.25%	0.25%
Class Adv	None	None	None
Class C	0.75%	0.25%	1.00%
Class Inst	None	None	None
Class Inst2	None	None	None
Class Inst3	None	None	None
Class R	0.50%	None	0.50%

The distribution and/or service fees for Class A, Class C, and Class R shares, as applicable, are subject to the requirements of Rule 12b-1 under the 1940 Act. The Distributor may retain these fees otherwise payable to financial intermediaries if the amounts due are below an amount determined by the Distributor in its sole discretion.

For Class A shares, the Distributor begins to pay these fees immediately after purchase, except in the following case, in which the Distributor begins to pay these fees 12 months after purchase: a purchase of Class A shares of $1 million or more that pay a Class A up-front commission to your financial intermediary and the financial intermediary has opted to receive such commission. The Distributor’s policy to otherwise begin to pay these fees immediately on

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Choosing a Share Class (continued)

Class A shares also applies to purchases of funds that do not pay an up-front sales commission on Class A shares, which includes Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund and Columbia U.S. Treasury Index Fund. For Class C shares, the Distributor begins to pay these fees 12 months after purchase. However, for Class C shares, financial intermediaries may opt to decline the up-front payment described in Choosing a Share Class – Sales Charges and Commissions – Class C Shares – Commissions and instead may receive these fees immediately after purchase. If the intermediary opts to receive the up-front payment, the Distributor retains the distribution and service fee for the first 12 months following the sale of Class C shares in order to recover the up-front payment made to financial intermediaries and to pay for other related expenses. For Class R shares, the Distributor begins to pay these fees immediately after purchase.

If you maintain shares of the Fund directly with the Fund, without working with a financial advisor or other financial intermediary, distribution and service fees may be retained by the Distributor as payment or reimbursement for incurring certain distribution and shareholder service related expenses.

Over time, these distribution and/or service fees will reduce the return on your investment and may cost you more than paying other types of sales charges. The Fund will pay these fees to the Distributor and/or to eligible financial intermediaries for as long as the distribution plan continues in effect, which is expected to be indefinitely. However, the Fund may reduce or discontinue payments at any time. Your financial intermediary may also charge you other additional fees for providing services to your account, which may be different from those described here.

Financial Intermediary Compensation

The Distributor, the Investment Manager and their affiliates make payments, from their own resources, to financial intermediaries, including other Ameriprise Financial affiliates, for marketing/sales support services relating to the Funds (Marketing Support Payments). Such payments are generally based upon one or more of the following factors: average net assets of the Funds attributable to that financial intermediary; gross sales of the Funds attributable to that financial intermediary; reimbursement of ticket charges (fees that a financial intermediary charges its representatives for effecting transactions in Fund shares); or a negotiated lump sum payment. While the financial arrangements may vary for each financial intermediary, Marketing Support Payments to any one financial intermediary are generally between 0.01% and 0.40% on an annual basis for payments based on average net assets of the Fund attributable to the financial intermediary, and between 0.05% and 0.25% on an annual basis for firms receiving a payment based on gross sales of the Funds attributable to the financial intermediary. The Distributor, the Investment Manager and their affiliates make payments with respect to a Fund or the Columbia Funds generally on a basis other than those described above or in larger amounts when dealing with certain financial intermediaries. Not all financial intermediaries receive Marketing Support Payments. The Distributor, the Investment Manager and their affiliates do not make Marketing Support Payments with respect to Class Inst3 shares of the Columbia Acorn Funds.

In addition, the Transfer Agent has certain arrangements in place to compensate financial intermediaries, including other Ameriprise Financial affiliates, that hold Fund shares through networked and omnibus accounts, including omnibus retirement plans, for services that they provide to beneficial Fund shareholders (Shareholder Services). Shareholder Services and related fees vary by financial intermediary and according to distribution channel and may include sub-accounting, sub-transfer agency, participant recordkeeping, shareholder or participant reporting, shareholder or participant transaction processing, maintenance of shareholder records, preparation of account statements and provision of customer service, and are not intended to include services that are primarily intended to result in the sale of Fund shares. Payments for Shareholder Services vary by financial intermediary and according to distribution channel, but generally are not expected, with certain limited exceptions, to exceed 0.40% of the average aggregate value of the Fund’s shares. Payments to financial intermediaries in excess of the amounts paid by the Fund are borne by the Distributor, the Investment Manager and/or their affiliates.

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Generally, each Fund in the Columbia Acorn Family of Funds compensates the Transfer Agent for payments made for Shareholder Services, for each share class except Class Inst3. Effective July 1, 2017, the Columbia Acorn Funds compensate the Transfer Agent for payments made for Shareholder Services as follows:

Financial Intermediary Distribution Channel	Fee Rate
Retirement	up to 0.18% of Fund assets held by intermediaries or platforms charging an asset-based fee, or $18 per account held by intermediaries or platforms charging a per account fee
Fund supermarket transaction fee (TF)	up to 0.12% of Fund assets held by intermediaries or platforms charging an asset-based fee, or $16 per account held for intermediaries or platforms charging a per account fee
Fund supermarket no-transaction fee (NTF)	up to 0.18% of Fund assets held by intermediaries or platforms charging an asset-based fee, or $18 per account held by intermediaries or platforms charging a per account fee
Bank	up to 0.10% of Fund assets held by intermediaries or platforms charging an asset-based fee, or $20 per account held by intermediaries or platforms charging a per account fee
Broker-dealer	up to 0.13% of Fund assets held by intermediaries or platforms charging an asset-based fee, or $16 per account held by intermediaries or platforms charging a per account fee

With respect to Class Inst2 and Class Inst3 shares of the Fund, total annual compensation payable to the Transfer Agent may not exceed, respectively, 0.07% and 0.02% of the average daily net assets of the Class. For additional details about the application of the Columbia Acorn Funds’ fee limits, please refer to the SAI.

The Transfer Agent does not pay financial intermediaries for Shareholder Services, and the Fund does not compensate the Transfer Agent for any Shareholder Services provided by financial intermediaries with respect to Class Inst3 shares of the Columbia Acorn Funds. The Fund believes that the fee levels paid to the Transfer Agent are reasonably related to the Shareholder Services provided, but payments may vary and there can be no assurance that the Fund will be able to identify with specificity the costs or particular Shareholder Services for which compensation is paid.

In addition to the payments described above, the Distributor, the Investment Manager and their affiliates typically make other payments or allow promotional incentives to certain broker-dealers to the extent permitted by the Securities and Exchange Commission (the SEC) and Financial Industry Regulatory Authority (FINRA) rules and by other applicable laws and regulations.

Amounts paid by the Distributor, the Investment Manager and their affiliates are paid out of their own resources and do not increase the amount paid by you or the Fund. You can find further details in the SAI about the payments made by the Distributor, the Investment Manager and their affiliates, as well as a list of the financial intermediaries, including Ameriprise Financial affiliates, to which the Distributor and the Investment Manager have agreed to make Marketing Support Payments and pay Shareholder Services fees.

Your financial intermediary may charge you fees and commissions in addition to those described in this prospectus. You should consult with your financial intermediary and review carefully any disclosure your financial intermediary provides regarding its services and compensation. Depending on the financial arrangement in place at any particular time, a financial intermediary and its financial advisors may have a conflict of interest or financial incentive for recommending the Fund or a particular share class over others.

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Buying, Selling and Exchanging Shares

Share Price Determination

The price you pay or receive when you buy, sell or exchange shares is the Fund's next determined net asset value (or NAV) per share for a given share class. The Fund calculates the NAV per share for each class of shares of the Fund at the end of each business day, with the value of the Fund's shares based on the total value of all of the securities and other assets that it holds as of such specified time.

 FUNDamentals

NAV Calculation

Each of the Fund's share classes calculates its NAV per share as follows:

NAV per share =  (Value of assets of the share class) – (Liabilities of the share class)
Number of outstanding shares of the class

 FUNDamentals

Business Days

A business day is any day that the New York Stock Exchange (NYSE) is open. A business day ends at (i) the scheduled close of the NYSE for such day (usually 4:00 p.m. Eastern Time or such other time as the NYSE may schedule), (ii) the scheduled close of the NYSE (usually 4:00 p.m. Eastern Time) on any business day on which the NYSE has an unscheduled close or intraday trading halt or other disruption, regardless of the time of such unscheduled close, halt or disruption or whether trading resumes, or (iii) such other time as the Board may from time to time determine. On holidays and other days when the NYSE is closed, the Fund’s NAV is not calculated and the Fund does not accept buy or sell orders. However, the value of the Fund’s assets may still be affected on such days to the extent that the Fund holds foreign securities that trade on days that foreign securities markets are open.

Equity securities are valued primarily on the basis of market quotations reported on stock exchanges and other securities markets around the world. Certain equity securities, debt securities and other assets are valued differently. For instance, short-term investments maturing in 60 days or less are valued primarily using the amortized cost method and those maturing in excess of 60 days are valued at the readily available market price. For a Fund organized as a fund-of-funds, its investments in other funds are valued at their NAVs. Market quotations are obtained from outside pricing services approved and monitored pursuant to a policy approved by the Fund’s Board.

If a market price is not readily available or is deemed not to reflect market value, the security will be valued in good faith based on a determination of the security's fair value pursuant to the Portfolio Pricing Policy approved by the Board. The Portfolio Pricing Policy provides that fair value determinations will be made using the methodology set forth in the Policy and deemed most appropriate under the circumstances and considering all available, relevant factors and indications of value. The Portfolio Pricing Policy provides that fair valuation may be used to price securities that trade on a foreign exchange when a significant event has occurred after the foreign exchange closes but before the time at which the Fund's share price is calculated. In addition, a statistical fair valuation process is applied daily to adjust prices of foreign securities traded on foreign exchanges in time zones different from the United States utilizing the services of a designated pricing vendor. Although the use of statistical fair valuation is intended to and may decrease opportunities for time zone arbitrage transactions, there can be no assurance that it will successfully decrease arbitrage opportunities. Please consult the SAI for more information on the factors to be considered in making fair value determinations; the significant events that may necessitate fair valuation of foreign securities; and the Fund's statistical fair valuation methodology.

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Buying, Selling and Exchanging Shares (continued)

When fair valuation is used to price securities, the values for those securities may be higher or lower than values used by another fund to price the security. Also, the use of fair valuation may cause the Fund's performance to diverge to a greater degree from the performance of various benchmarks used to compare the Fund's performance because benchmarks generally do not use fair valuation techniques. Because of the judgment involved in fair valuation decisions, there can be no assurance that the value ascribed to a particular security is accurate.

Transaction Rules and Policies

The Fund, the Distributor or the Transfer Agent may refuse any order to buy or exchange shares. If this happens, the Fund will return any money it received, but no interest will be paid on that money. Your financial intermediary may have rules and policies in place that are in addition to or different than those described below.

Order Processing

Orders to buy, sell or exchange Fund shares are processed on business days. Depending upon the class of shares, orders can be made by mail, by telephone or online. Orders received in “good form” by the Transfer Agent or your financial intermediary before the end of a business day are priced at the NAV per share (plus any applicable sales charge) of the Fund's applicable share class on that day. Orders received after the end of a business day will receive the next business day's NAV per share (plus any applicable sales charge). For Direct-at-Fund Accounts (as defined below), when a written order to buy, sell or exchange shares is sent to the Transfer Agent, the share price used to fill the order is the next price calculated by the Fund after the Transfer Agent receives the transaction request in “good form” at its transaction processing center (i.e., the Fund’s express mail address), not the P.O. Box provided for regular mail delivery. The market value of the Fund's investments may change between the time you submit your order and the time the Fund next calculates its NAV per share. The business day that applies to your order is also called the trade date.

“Good Form”

An order is in “good form” if the Transfer Agent or your financial intermediary has received payment (in the case of purchases) and all of the information and documentation it deems necessary to effect your order. For example, when you sell shares, “good form” means that your request (i) has complete instructions and written requests include the signatures of all account owners, (ii) is for an amount that is less than or equal to the shares in your account for which payment has been received and collected, (iii) has a Medallion Signature Guarantee for amounts greater than $100,000 and certain other transactions, as described below, and (iv) includes any other required documents completed and attached. For the documents required for sales by corporations, agents, fiduciaries, surviving joint owners and other legal entities, call 800.345.6611.

Medallion Signature Guarantees

The Transfer Agent may require a Medallion Signature Guarantee for your signature in order to process certain transactions, including if: (i) the transaction amount is over $100,000; (ii) you want your check made payable to someone other than the registered account owner(s); (iii) the address of record has changed within the last 30 days; (iv) you want the check mailed to an address other than the address of record; (v) you want proceeds to be sent according to existing bank account instructions not coded for outgoing Automated Clearing House (ACH) or wire, or to a bank account not on file; or (vi) you are changing legal ownership of your account.

A Medallion Signature Guarantee helps assure that a signature is genuine and not a forgery. A Medallion Signature Guarantee must be provided by an eligible guarantor institution including, but not limited to, the following: a bank, credit union, savings association, broker or dealer that participates in the Securities Transfer Association Medallion Program (STAMP), the Stock Exchange Medallion Program (SEMP) or the New York Stock Exchange Medallion Signature Program (MSP). For other transactions, the Transfer Agent may require a signature guarantee. Notarization by a notary public is not an acceptable signature guarantee. The Transfer Agent reserves the right to reject a signature guarantee and to request additional documentation for any transaction.

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Buying, Selling and Exchanging Shares (continued)

Customer Identification Program

Federal law requires the Fund to obtain and record specific personal information to verify your identity when you open an account. This information may include your name, address, date of birth (for individuals) and taxpayer or other government issued identification (e.g., social security number (SSN) or other taxpayer identification number (TIN)). If you fail to provide the requested information, the Fund may need to delay the date of your purchase or may be unable to open your account, which may result in a return of your investment monies. In addition, if the Fund is unable to verify your identity after your account is open, the Fund reserves the right to close your account or take other steps as deemed reasonable. The Fund will not be liable for any loss resulting from any purchase delay, application rejection or account closure due to a failure to provide proper identifying information.

Small Account Policy — Class A, Class C, and Class Inst Share Accounts Below the Minimum Account Balance

The Funds generally will automatically sell your shares if the value of your Fund account (treating each account of the Fund you own separately from any other account of the Fund you may own) falls below the applicable minimum account balance. Any otherwise applicable CDSC will not be imposed on such an automatic sale of your shares. Generally, you may avoid such an automatic sale by raising your account balance to at least $250 or consolidating your multiple accounts you may have with the Funds through an exchange (so as to maintain at least $250 in each of your accounts). The minimum account balance varies among share classes and types of accounts, as follows:

Minimum Account Balance
	Minimum Account Balance
For all classes and account types except those listed below	$250 (None for accounts with Systematic Investment Plans)
Individual Retirement Accounts for all classes except those listed below	None
Class Adv, Class Inst2, Class Inst3 and Class R	None

For shares held directly with the Funds’ Transfer Agent, if your shares are sold, the Transfer Agent will remit the sale proceeds to you. The Transfer Agent will send you written notification in advance of any automatic sale, which will provide details on how you may avoid such an automatic sale. Generally, you may avoid such an automatic sale by raising your account balance to at least $250, consolidating your multiple accounts you may have with the Funds through an exchange (so as to maintain at least $250 in each of your accounts), or setting up a Systematic Investment Plan. For more information, contact the Transfer Agent or your financial intermediary. The Transfer Agent's contact information (toll-free number and mailing addresses) as well as the Funds’ website address can be found at the beginning of the section Choosing a Share Class.

For shares purchased and held for your benefit through a financial intermediary, the Funds may instruct the intermediary to automatically sell your Fund shares if the transaction can be operationally administered by the intermediary.

Small Account Policy — Class A, Class C, and Class Inst Share Accounts Minimum Balance Fee

If the value of your Fund account (treating each account of the Fund you own separately from any other account of the Fund you may own) falls below the minimum initial investment requirement applicable to you for any reason, including as a result of market decline, your account generally could be subject to a $20 annual fee. The Transfer Agent will reduce the expenses paid by the Fund by any amounts it collects from the assessment of this fee. For Funds that do not have transfer agency expenses against which to offset the amount collected through assessment of this fee, the fee will be paid directly to the Fund. The Funds reserve the right to lower the account size trigger point for the minimum balance fee in any year or for any class of shares when we believe it is appropriate to do so in light of declines in the market value of Fund shares or for other reasons.

For shares held directly with the Funds’ Transfer Agent, this fee will be assessed through the automatic sale of Fund shares in your account. Any otherwise applicable CDSC will not be imposed on such an automatic sale of your shares. The Transfer Agent will send you written notification in advance of assessing any fee, which will provide

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Buying, Selling and Exchanging Shares (continued)

details on how you can avoid the imposition of such fee. Generally, you may avoid the imposition of such fee by raising your Fund account balance, consolidating your multiple accounts you may have with the Funds, or setting up a Systematic Investment Plan that invests at least monthly. For more information, contact the Transfer Agent or your financial intermediary. The Transfer Agent's contact information (toll-free number and mailing addresses) as well as the Funds’ website address can be found at the beginning of the section Choosing a Share Class.

For shares purchased and held for your benefit through a financial intermediary, this fee could be assessed through the automatic sale of Fund shares in your account if instructed by the Fund and the transaction can be operationally administered by the intermediary.

Exceptions to the Small Account Policy (Accounts Below Minimum Account Balance) and Minimum Balance Fee

The automatic sale of Fund shares in accounts under $250 and the annual minimum balance fee described above do not apply to shareholders of Class Adv, Class Inst2, Class Inst3 and Class R shares; shareholders holding their shares through financial intermediary networked accounts; wrap fee and omnibus accounts; accounts with active monthly Systematic Investment Plans; certain qualified retirement plans; and health savings accounts. The automatic sale of Fund shares of accounts under the applicable minimum account balance does not apply to individual retirement plans.

Small Account Policy — Financial Intermediary Networked and Wrap Fee Accounts

The Funds may automatically redeem, at any time, financial intermediary networked accounts and wrap fee accounts that have account balances of $20 or less or have less than one share.

For shares purchased and held for your benefit through a financial intermediary, the Funds may instruct the intermediary to automatically sell your Fund shares if the transaction can be operationally administered by the intermediary.

Information Sharing Agreements

As required by Rule 22c-2 under the 1940 Act, the Funds or certain of their service providers will enter into information sharing agreements with financial intermediaries, including participating life insurance companies and financial intermediaries that sponsor or offer retirement plans through which shares of the Funds are made available for purchase. Pursuant to Rule 22c-2, financial intermediaries are required, upon request, to: (i) provide shareholder account and transaction information; and (ii) execute instructions from the Fund to restrict or prohibit further purchases of Fund shares by shareholders who have been identified by the Fund as having engaged in transactions that violate the Fund's excessive trading policies and procedures.

Excessive Trading Practices Policy

Right to Reject or Restrict Share Transaction Orders— The Fund is intended for investors with long-term investment purposes and is not intended as a vehicle for frequent trading activity (market timing) that is excessive. Investors should transact in Fund shares primarily for investment purposes. The Board has adopted excessive trading policies and procedures that are designed to deter excessive trading by investors (the Excessive Trading Policies and Procedures). The Fund discourages and does not accommodate excessive trading.

The Fund reserves the right to reject, without any prior notice, any purchase or exchange order for any reason, and will not be liable for any loss resulting from rejected orders. For example, the Fund may in its sole discretion restrict or reject a purchase or exchange order even if the transaction is not subject to the specific limitation described below if the Fund or its agents determine that accepting the order could interfere with efficient management of the Fund's portfolio or is otherwise contrary to the Fund's best interests. The Excessive Trading Policies and Procedures apply equally to purchase or exchange transactions communicated directly to the Transfer Agent and to those received by financial intermediaries.

Specific Buying and Exchanging Limitations — If the Fund detects that an investor has made two “material round trips” in any 28-day period, it will generally reject the investor's future purchase orders, including exchange purchase orders, involving any Fund.

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Buying, Selling and Exchanging Shares (continued)

For these purposes, a “round trip” is a purchase or exchange into the Fund followed by a sale or exchange out of the Fund, or a sale or exchange out of the Fund followed by a purchase or exchange into the Fund. A “material” round trip is one that is deemed by the Fund to be material in terms of its amount or its potential detrimental impact on the Fund. Independent of this limit, the Fund may, in its sole discretion, reject future purchase orders by any person, group or account that appears to have engaged in any type of excessive trading activity.

These limits generally do not apply to automated transactions or transactions by registered investment companies in a “fund-of-funds” structure. These limits do not apply to payroll deduction contributions by retirement plan participants, transactions initiated by a retirement plan sponsor or certain other retirement plan transactions consisting of rollover transactions, loan repayments and disbursements, and required minimum distribution redemptions. They may be modified or rescinded for accounts held by certain retirement plans to conform to plan limits, for considerations relating to the Employee Retirement Income Security Act of 1974 or regulations of the Department of Labor, and for certain asset allocation or wrap programs. Accounts known to be under common ownership or control generally will be counted together, but accounts maintained or managed by a common intermediary generally will not be considered to be under common ownership or control. The Fund reserves the right to modify these restrictions at any time without prior notice to shareholders. In addition, the Fund may, in its sole discretion, reinstate trading privileges that have been revoked under the Fund's Excessive Trading Policies and Procedures.

Limitations on the Ability to Detect and Prevent Excessive Trading Practices — The Fund takes various steps designed to detect and prevent excessive trading, including daily review of available shareholder transaction information. However, the Fund receives buy, sell or exchange orders through financial intermediaries, and cannot always know of or reasonably detect excessive trading that may be facilitated by financial intermediaries or by the use of the omnibus account arrangements they offer. Omnibus account arrangements are common forms of holding shares of mutual funds, particularly among certain financial intermediaries such as broker-dealers, retirement plans and variable insurance products. These arrangements often permit financial intermediaries to aggregate their clients' transactions and accounts, and in these circumstances, the identities of the financial intermediary clients that beneficially own Fund shares are often not known to the Fund.

Some financial intermediaries apply their own restrictions or policies to their clients’ transactions and accounts, which may be more or less restrictive than those described here. This may impact the Fund's ability to curtail excessive trading, even where it is identified. For these and other reasons, it is possible that excessive trading may occur despite the Fund's efforts to detect and prevent it.

Although these restrictions and policies involve judgments that are inherently subjective and may involve some selectivity in their application, the Fund seeks to act in a manner that it believes is consistent with the best interests of Fund shareholders in making any such judgments.

Risks of Excessive Trading — Excessive trading creates certain risks to the Fund's long-term shareholders and may create the following adverse effects:

■ negative impact on the Fund's performance;

■ potential dilution of the value of the Fund's shares;

■ interference with the efficient management of the Fund's portfolio, such as the need to maintain undesirably large cash positions, the need to use its line of credit or the need to buy or sell securities it otherwise would not have bought or sold;

■ losses on the sale of investments resulting from the need to sell securities at less favorable prices;

■ increased taxable gains to the Fund's remaining shareholders resulting from the need to sell securities to meet sell orders; and

■ increased brokerage and administrative costs.

To the extent that the Fund invests significantly in foreign securities traded on markets that close before the Fund's valuation time, it may be particularly susceptible to dilution as a result of excessive trading. Because events may occur after the close of foreign markets and before the Fund's valuation time that influence the value of foreign

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securities, investors may seek to trade Fund shares in an effort to benefit from their understanding of the value of foreign securities as of the Fund's valuation time. This is often referred to as price arbitrage. The Fund has adopted procedures designed to adjust closing market prices of foreign securities under certain circumstances to reflect what the Fund believes to be the fair value of those securities as of its valuation time. To the extent the adjustments do not work fully, investors engaging in price arbitrage may cause dilution in the value of the Fund's shares held by other shareholders.

The Columbia Acorn Funds may invest in thinly traded equity securities of small-capitalization companies. Because

these securities are often traded infrequently, investors may seek to trade Fund shares in an effort to benefit from their understanding of the value of these securities as of the Fund's valuation time. This is also a type of price arbitrage. Any such frequent trading strategies may interfere with efficient management of the Fund's portfolio to a greater degree than would be the case for mutual funds that invest only, or significantly, in highly liquid securities, in part because the Fund may have difficulty selling these particular investments at advantageous times or prices to satisfy large and/or frequent sell orders. Any successful price arbitrage may also cause dilution in the value of Fund shares held by non-redeeming shareholders.

Opening an Account and Placing Orders

We encourage you to consult with a financial advisor who can help you with your investment decisions and who can help you open an account. Once you have an account, you can buy, sell or exchange shares by contacting your financial advisor who will send your order to the Transfer Agent or your financial intermediary. As described below, once you have an account you can also communicate your orders directly to the Transfer Agent by mail, by telephone or online.

The Funds are generally available directly and through broker-dealers, banks and other financial intermediaries or institutions, and through certain qualified and non-qualified plans, wrap fee products or other investment products sponsored by financial intermediaries. You may buy, sell, or exchange shares through your financial intermediary. If you maintain your account directly with your financial intermediary, you must contact that agent to process your transaction.

Not all financial intermediaries offer the Funds (or all classes of Fund shares) and certain financial intermediaries that offer the Funds may not offer all Funds on all investment platforms or programs. Please consult with your financial intermediary to determine the availability of the Funds. If you set up an account at a financial intermediary that does not have, and is unable to obtain, a selling agreement with the Distributor, you will not be able to transfer Fund holdings to that account. In that event, you must either maintain your Fund holdings with your current financial intermediary or find another financial intermediary with a selling agreement.

Financial intermediaries that offer the Funds may charge you additional fees for the services they provide and they may have different policies that are not described in this prospectus. An investor transacting in a class of Fund shares without any front-end sales charge, CDSC, or other asset-based fee for sales or distribution, such as a Rule 12b-1 fee, may be required to pay a commission to the financial intermediary for effecting such transactions. The Funds are offered in a number of different share classes that have different fees and expenses and other features. Some differences in the policies of different financial intermediaries may include different minimum investment amounts, exchange privileges, Fund/class choices and cutoff times for investments. Additionally, recordkeeping, transaction processing and payments of distributions relating to your account may be performed by the financial intermediaries through which your shares of the Fund are held. Since the Fund (and its service providers) may not have a record of your account transactions, you should always contact the financial intermediary through which you purchased or at which you maintain your shares of the Fund to make changes to your account, to give instructions concerning your account, or to obtain information about your account. The Fund and its service providers, including the Distributor and the Transfer Agent, are not responsible for the failure of any financial intermediary to carry out its obligations to its customers.

The Fund may engage financial intermediaries to receive purchase, exchange and sell orders on its behalf. Accounts established directly with the Fund will be serviced by the Transfer Agent. The Funds, the Transfer Agent and the Distributor do not provide investment advice.

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Direct-At-Fund Accounts (Accounts Held Directly with the Fund)

Fund shares can be held in a variety of ways. You can hold Fund shares through an account established and held through the financial intermediary through which you purchased Fund shares, or you or your financial intermediary can establish an account directly with the Fund, in which case you will receive Fund account transaction confirmations and statements from the Transfer Agent, and not your financial intermediary (Direct-at-Fund Accounts). Direct-at-Fund Accounts include accounts held at the Transfer Agent that do not or no longer have a financial intermediary assigned to them.

To open a Direct-at-Fund Account, complete a Fund account application with your financial advisor or investment professional, and mail the account application to the Transfer Agent. Account applications may be obtained at columbiathreadneedleus.com or may be requested by calling 800.345.6611. Make your check payable to the Fund. You will be assessed a $15 fee for any checks rejected by your financial institution due to insufficient funds or other reasons. The Funds do not accept cash, credit card convenience checks, money orders, traveler's checks, starter checks, third or fourth party checks, or other cash equivalents.

Mail your check and completed application to the Transfer Agent at its regular or express mail address that can be found at the beginning of the section Choosing a Share Class. You may also use these addresses to request an exchange or redemption of Fund shares. When a written order to buy, sell or exchange shares is sent to the Transfer Agent, the share price used to fill the order is the next price calculated by the Fund after the Transfer Agent receives your transaction request in “good form” at its transaction processing center (i.e., the Fund’s express mail address), not the P.O. Box provided for regular mail delivery.

You will be sent a statement confirming your purchase and any subsequent transactions in your account. You will also be sent quarterly and annual statements detailing your transactions in the Fund and the other Funds you own under the same account. Duplicate quarterly account statements for the current year and duplicate annual statements for the most recent prior calendar year will be sent to you free of charge. Copies of year-end statements for prior years are available for a fee. Please contact the Transfer Agent for more information.

Written Transactions – Direct-at-Fund Accounts

If you have a Direct-at-Fund Account, you can communicate written buy, sell or exchange orders to the Transfer Agent at its address that can be found at the beginning of the section Choosing a Share Class. When a written order to buy, sell or exchange shares is sent to the Transfer Agent, the share price used to fill the order is the next price calculated by the Fund after the Transfer Agent receives your transaction request in “good form” at its transaction processing center (i.e., the Fund’s express mail address), not the P.O. Box provided for regular mail delivery.

Include in your transaction request letter: your name; the name of the Fund(s); your account number; the class of shares to be purchased, exchanged or sold; your SSN or other TIN; the dollar amount or number of shares you want to purchase, exchange or sell; specific instructions regarding delivery of any redemption proceeds or exchange destination (i.e., the Fund/class to be exchanged into); signature(s) of all registered account owner(s); and any special documents the Transfer Agent may require in order to process your order.

Corporate, trust or partnership accounts may need to send additional documents. Payment will be mailed to the address of record and made payable to the names listed on the account, unless your request specifies differently and is signed by all owners.

Telephone Transactions – Direct-at-Fund Accounts

For Class A, Class C, Class Inst, Class Inst3 and Class R shares, if you have a Direct-at-Fund Account, you may place orders to buy, sell or exchange shares by telephone through the Transfer Agent. To place orders by telephone, call 800.422.3737. Have your account number and SSN or TIN available when calling.

You can sell Fund shares via telephone and receive redemption proceeds: by electronic funds transfer via ACH, by wire, or by check to the address of record, subject to a maximum of $100,000 of shares per day, per Fund account. You can buy Fund shares via telephone by electronic funds transfer via ACH from your bank account up to a maximum

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of $100,000 of shares per day, per Fund account, or by wire from your bank account without a maximum. See below for more information regarding wire and electronic fund transfer transactions. Certain restrictions apply, so please call the Transfer Agent at 800.422.3737 for this and other information in advance of any need to transact via telephone.

Telephone orders may not be as secure as written orders. The Fund will take reasonable steps to confirm that telephone instructions are genuine. For example, we require proof of your identification before we will act on instructions received by telephone and may record telephone conversations. However, the Fund and its agents will not be responsible for any losses, costs or expenses resulting from an unauthorized telephone instruction when reasonable steps have been taken to confirm that telephone instructions are genuine. Telephone orders may be difficult to complete during periods of significant economic or market change or business interruption.

Online Transactions – Direct-at-Fund Accounts

For Class A, Class C, Class Inst, Class Inst3 and Class R shares, if you have a Direct-at-Fund Account, you may be able to place orders to buy, sell, or exchange shares online. Contact the Transfer Agent at 800.345.6611 for more information on certain account trading restrictions and the special sign-up procedures required for online transactions. You can also go to columbiathreadneedleus.com/investor/ to sign up for online transactions. The Transfer Agent has procedures in place to authenticate electronic orders you send through the internet. You will be required to accept the terms of an online agreement and to establish an online account and utilize a password in order to access online account services. You can sell a maximum of $100,000 of shares per day, per Fund account through your online account if you qualify for internet orders. Wire transactions are not permitted online.

Wire Transactions – Direct-at-Fund Accounts

If you hold a Direct-at-Fund Account, you may purchase or redeem Class A, Class C, Class Inst, Class Inst3 and Class R shares of a Fund by wiring money from (or to) your bank account to (or from) your Fund account. You must set up this feature prior to your request unless you are submitting your request in writing, which may require a Medallion Signature Guarantee. Please contact the Transfer Agent by calling 800.422.3737 to obtain the necessary forms and requirements. The Transfer Agent charges a fee for shares sold by wire. The Transfer Agent may waive the fee for certain accounts. In the case of a redemption, the receiving bank may charge an additional fee. The minimum amount that can be redeemed by wire is $500. When selling Fund shares via a telephone request, the maximum amount that can be redeemed via wire transfer is $100,000 per day, per Fund account. Wire transactions are not permitted online.

Electronic Funds Transfer via ACH – Direct-at-Fund Accounts

If you hold a Direct-at-Fund Account, you may purchase or redeem Class A, Class C, Class Inst, Class Inst3 and Class R shares of a Fund by electronically transferring money via Automated Clearing House (ACH) from (or to) your bank account to (or from) your Fund account subject to a maximum of $100,000 of shares per day, per Fund account. You must set up this feature prior to your request, unless you are submitting your request in writing, which may require a Medallion Signature Guarantee. Please contact the Transfer Agent by calling 800.422.3737 to obtain the necessary forms and requirements. Your bank may take up to three business days to post an electronic funds transfer to (or from) your Fund account.

Buying Shares

Eligible Investors

Class A Shares

Class A shares are available to the general public for investment.

Class Adv Shares

Class Adv shares are available only to (i) omnibus retirement plans, including self-directed brokerage accounts within omnibus retirement plans that clear through institutional no transaction fee (NTF) platforms, (ii) trust companies or similar institutions, (iii) broker-dealers, banks, trust companies and similar institutions that clear Fund share

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transactions for their client or customer investment advisory or similar accounts through designated financial intermediaries and their mutual fund trading platforms that have been granted specific written authorization from the Transfer Agent with respect to Class Adv eligibility apart from selling, servicing or similar agreements, (iv) 501(c)(3) charitable organizations, (v) 529 plans, (vi) health savings accounts, (vii) investors participating in a fee-based advisory program sponsored by a financial intermediary or other entity that is not compensated by the Fund for those services, other than payments for shareholder servicing or sub-accounting performed in place of the Transfer Agent, and (viii) commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Adv shares within such platform.

Class C Shares

Class C shares are available to the general public for investment, except that Direct-at-Fund Accounts that do not have a financial intermediary assigned to them are not permitted to purchase Class C shares; Class C share purchase orders received on or after such date from Direct-at-Fund Accounts that do not have a financial intermediary assigned to the account will automatically be invested in Class A shares of the same Fund.

Class Inst Shares

Class Inst shares are available only to the categories of eligible investors described below under Class Inst Shares Minimum Initial Investments. Financial intermediaries that clear Fund share transactions through designated financial intermediaries and their mutual fund trading platforms that were given specific written notice from the Transfer Agent of the termination, effective March 29, 2013, of their eligibility for new purchases of Class Inst shares and omnibus retirement plans are not permitted to establish new Class Inst accounts, subject to certain exceptions described below.

Omnibus retirement plans that opened and, subject to certain exceptions, funded a Class Inst account with the Fund as of the close of business on March 28, 2013 and have continuously held Class Inst shares in such account after such date (each, a grandfathered plan), may generally continue to make additional purchases of Class Inst shares, open new Class Inst accounts and add new participants. In addition, an omnibus retirement plan affiliated with a grandfathered plan may, in the sole discretion of the Distributor, open new Class Inst accounts in a Fund if the affiliated plan opened a Class Inst account on or before March 28, 2013. If an omnibus retirement plan invested in Class Inst shares changes recordkeepers after March 28, 2013, any new accounts established for that plan may not be established in Class Inst shares, but such a plan may establish new accounts in a different share class for which the plan is eligible.

Accounts of financial intermediaries (other than omnibus retirement plans, which are discussed above) that clear Fund share transactions for their client or customer accounts through designated financial intermediaries and their mutual fund trading platforms that received specific written notice from the Transfer Agent of the termination, effective March 29, 2013, of their eligibility for new purchases of Class Inst shares will not be permitted to establish new Class Inst accounts or make additional purchases of Class Inst shares (other than through reinvestment of distributions). Any such account may, at its holder’s option, exchange Class Inst shares of a Fund, without the payment of a sales charge, for Class A shares of the same Fund.

Class Inst2 Shares

Class Inst2 shares are available only to (i) certain registered investment advisers and family offices that clear Fund share transactions for their client or customer accounts through designated financial intermediaries and their mutual fund trading platforms that have been granted specific written authorization from the Transfer Agent with respect to Class Inst2 eligibility apart from selling, servicing or similar agreements; (ii) omnibus retirement plans; (iii) health savings accounts, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst2 shares within such platform and that Fund shares are held in an omnibus account; and (iv) institutional investors that are clients of the Columbia Threadneedle Global Institutional Distribution Team that invest in Class Inst2 shares for their own account through platforms approved by the Distributor or an affiliate thereof to offer and/or service Class Inst2 shares within such platform. Prior to November 8, 2012, Class Inst2

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shares were closed to new investors and new accounts, subject to certain exceptions. Existing shareholders who do not satisfy the new eligibility requirements for investment in Class Inst2 may not establish new Class Inst2 accounts but may continue to make additional purchases of Class Inst2 shares in accounts opened and funded prior to November 8, 2012; provided, however, that investment advisory programs and similar programs that opened a Class Inst2 account as of May 1, 2010, and continuously hold Class Inst2 shares in such account after such date, may generally not only continue to make additional purchases of Class Inst2 shares but also open new Class Inst2 accounts for such pre-existing programs and add new shareholders in the program.

Class Inst3 Shares

Class Inst3 shares are available to: (i) group retirement plans that maintain plan-level or omnibus accounts with the Fund (through the Transfer Agent); (ii) institutional investors that are clients of the Columbia Threadneedle Global Institutional Distribution Team that invest in Class Inst3 shares for their own account through platforms approved by the Distributor or an affiliate thereof to offer and/or service Class Inst3 shares within such platform; (iii) collective trust funds; (iv) affiliated or unaffiliated mutual funds (e.g., funds operating as funds-of-funds); (v) fee-based platforms of financial intermediaries (or the clearing intermediary that they trade through) that have an agreement with the Distributor or an affiliate thereof that specifically authorizes the financial intermediary to offer and/or service Class Inst3 shares within such platform, provided also that Fund shares are held in an omnibus account; (vi) commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst3 shares within such platform and that Fund shares are held in an omnibus account; (vii) health savings accounts, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst3 shares within such platform and that Fund shares are held in an omnibus account; and (viii) bank trust departments, subject to an agreement with the Distributor that specifically authorizes offering Class Inst3 shares and provided that Fund shares are held in an omnibus account. In each case above where noted that Fund shares are required to be held in an omnibus account, the Distributor may, in its discretion, determine to waive this requirement.

Class R Shares

Class R shares are available only to eligible health savings accounts sponsored by third party platforms, including those sponsored by Ameriprise Financial affiliates, eligible retirement plans and, in the sole discretion of the Distributor, other types of retirement accounts held through platforms maintained by financial intermediaries approved by the Distributor. Eligible retirement plans include any retirement plan other than individual 403(b) plans. Class R shares are generally not available for investment through retail nonretirement accounts, traditional and Roth IRAs, Coverdell Education Savings Accounts, SEPs, SAR-SEPs, Simple IRAs or 529 tuition programs. Contact the Transfer Agent or your retirement plan or health savings account administrator for more information about investing in Class R shares.

Additional Eligible Investors

In addition, the Distributor, in its sole discretion, may accept investments in any share class from investors other than those listed in this prospectus, and may also waive certain eligibility requirements for operational and other reasons, including but not limited to any requirement to maintain Fund shares in networked or omnibus accounts.

Minimum Initial Investments

The table below shows the Fund’s minimum initial investment requirements, which may vary by class and type of account.

The Fund reserves the right to redeem your shares if your account falls below the Fund’s minimum initial investment requirement.

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Minimum Initial Investments
	Minimum Initial Investment(a)	Minimum Initial Investment for Accounts with Systematic Investment Plans
For all classes and account types except those listed below	$2,000	$100
Individual Retirement Accounts for all classes except those listed below	$1,000	$100
Group retirement plans	None	N/A
Class Adv and Class Inst	$0, $1,000 or $2,000(b)	$100(b)
Class Inst2 and Class R	None	N/A
Class Inst3	$0, $1,000, $2,000 or $1 million(c)	$100(c)

(a) If your Class A, Class Adv, Class C, Class Inst, or Class Inst3 shares account balance falls below the minimum initial investment amount for any reason, including a market decline, you may be asked to increase it to the minimum initial investment amount or establish a monthly Systematic Investment Plan. If you do not do so, your account will be subject to a $20 annual low balance fee and/or shares may be automatically redeemed and the proceeds mailed to you if the account falls below the minimum account balance. See Buying, Selling and Exchanging Shares — Transaction Rules and Policies above. There is no minimum initial investment in Class A shares for accounts held in an omnibus account on a mutual fund only platform offered through your financial intermediary.

(b) The minimum initial investment in Class Adv shares is $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts) for commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customers, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Adv shares within such platform; for all other eligible Class Adv share investors (see Buying Shares – Eligible Investors – Class Adv Shares above), there is no minimum initial investment. The minimum initial investment amount for Class Inst shares is $0, $1,000 or $2,000 depending upon the category of eligible investor. See — Class Inst Shares Minimum Initial Investments below. The minimum initial investment amount for Systematic Investment Plan accounts is the same as the amount set forth in the first two rows of the table, as applicable.

(c) There is no minimum initial investment in Class Inst3 shares for: group retirement plans that maintain plan-level or omnibus accounts with the Fund; collective trust funds; affiliated or unaffiliated mutual funds (e.g., funds operating as funds-of-funds); and fee -based platforms of financial intermediaries (or the clearing intermediary that they trade through) that have an agreement with the Distributor or an affiliate thereof that specifically authorizes the financial intermediary to offer and/or service Class Inst3 shares within such platform and Fund shares are held in an omnibus account. The minimum initial investment in Class Inst3 shares is $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts) for commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst3 shares within such platform and Fund shares are held in an omnibus account. The minimum initial investment in Class Inst3 shares is $1 million, unless waived in the discretion of the Distributor, for the following investors: institutional investors that are clients of the Columbia Threadneedle Global Institutional Distribution Team that invest in Class Inst3 shares for their own account through platforms approved by the Distributor or an affiliate thereof to offer and/or service Class Inst3 shares within such platform; and bank trust departments, subject to an agreement with the Distributor that specifically authorizes offering Class Inst3 shares and provided that Fund shares are held in an omnibus account. The Distributor may, in its discretion, waive the $1 million minimum initial investment required for these Class Inst3 investors. In each case above where noted that Fund shares are required to be held in an omnibus account, the Distributor, may, in its discretion, determine to waive this requirement.

Additional Information about Minimum Initial Investments

The minimum initial investment requirements may be waived for accounts that are managed by an investment professional, or for accounts held in approved discretionary or non-discretionary wrap programs. The Distributor, in its sole discretion, may also waive minimum initial investment requirements for other account types.

Minimum investment and related requirements may be modified at any time, with or without prior notice. If your account is closed and then re-opened with a Systematic Investment Plan, your account must meet the then-current applicable minimum initial investment.

Class Inst Shares Minimum Initial Investments

There is no minimum initial investment in Class Inst shares for the following categories of eligible investors:

■ Any health savings account sponsored by a third party platform.

■ Any investor participating in an account sponsored by a financial intermediary or other entity (that provides services to the account) that is paid a fee-based advisory fee by the investor and that is not compensated by the Fund for those services, other than payments for shareholder servicing or sub-accounting performed in place of the Transfer Agent.

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■ Any commissionable brokerage account, if a financial intermediary has received a written approval from the Distributor to waive the minimum initial investment in Class Inst shares.

■ Any Trustee (or family member) of Columbia Acorn Trust.

■ Any employee (or family member) of the Investment Manager.

The minimum initial investment in Class Inst shares for the following categories of eligible investors is $1,000:

■ Individual retirement accounts (IRAs) on commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst shares within such platform.

■ Any current employee of Columbia Management Investment Advisers LLC, the Distributor or the Transfer Agent and immediate family members of any of the foregoing who share the same address are eligible to invest in Class Inst shares through an individual retirement account (IRA). If you maintain your account with a financial intermediary, you must contact that financial intermediary each time you seek to purchase shares to notify them that you qualify for Class Inst shares. If Class Inst shares are not available at your financial intermediary, you may consider opening a Direct-at-Fund Account. It is your obligation to advise your financial intermediary or (in the case of Direct-at-Fund Accounts) the Transfer Agent that you qualify for Class Inst shares; be prepared to provide proof thereof.

The minimum initial investment in Class Inst shares for the following categories of eligible investors is $2,000:

■ Investors (except investors in individual retirement accounts (IRAs)) who purchase Fund shares through commissionable brokerage platforms where the financial intermediary holds the shares in an omnibus account and, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst shares within such platform.

■ Any current employee of Columbia Management Investment Advisers LLC, the Distributor or the Transfer Agent and immediate family members of any of the foregoing who share the same address are eligible to invest in Class Inst shares (other than individual retirement accounts (IRAs), for which the minimum initial investment is $1,000). If you maintain your account with a financial intermediary, you must contact that financial intermediary each time you seek to purchase shares to notify them that you qualify for Class Inst shares. If Class Inst shares are not available at your financial intermediary, you may consider opening a Direct-at-Fund Account. It is your obligation to advise your financial intermediary or (in the case of Direct-at-Fund Accounts) the Transfer Agent that you qualify for Class Inst shares; be prepared to provide proof thereof.

■ Certain financial institutions and intermediaries, such as insurance companies, trust companies, banks, endowments, investment companies or foundations, buying shares for their own account, including Ameriprise Financial and its affiliates and/or subsidiaries.

■ Bank trust departments that assess their clients an asset-based fee.

■ Any trustee or director (or family member of a trustee or director) of a fund distributed by the Distributor (other than the Columbia Acorn Funds).

■ Certain other investors as set forth in more detail in the SAI.

Systematic Investment Plan

The Systematic Investment Plan allows you to schedule regular purchases via automatic transfers from your bank account to the Fund on a monthly, quarterly or semiannual basis. Contact the Transfer Agent or your financial intermediary to set up the plan. Systematic Investment Plans may not be available for all share classes. With the exception of Columbia Government Money Market Fund, Systematic Investment Plan purchases will be confirmed on your quarterly account statement. Columbia Government Money Market Fund Systematic Investment Plan purchases will be confirmed at the time of the purchase. If establishing a Systematic Investment Plan to reduce the initial fund minimum, the plan needs to be established monthly to avoid the small account fee.

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Dividend Diversification

Generally, you may automatically invest Fund distributions into the same class of shares (and in some cases certain other classes of shares) of another Fund without paying any applicable front-end sales charge. Call the Transfer Agent at 800.345.6611 for details. The ability to invest distributions from one Fund to another Fund may not be available to accounts held at all financial intermediaries.

Other Purchase Rules You Should Know

■ Once the Transfer Agent or your financial intermediary receives your purchase order in “good form,” your purchase will be made at the Fund’s next calculated public offering price per share, which is the NAV per share plus any sales charge that applies (i.e., the trade date).

■ Once the Fund receives your purchase request in “good form,” you cannot cancel it after the market closes.

■ You generally buy Class A shares at the public offering price per share because purchases of these share classes are generally subject to a front-end sales charge.

■ You buy Class Adv, Class C, Class Inst, Class Inst2, Class Inst3 and Class R shares at NAV per share because no front-end sales charge applies to purchases of these share classes.

■ The Distributor and the Transfer Agent reserve the right to cancel your order request if the Fund does not receive payment within two business days of receiving your purchase order request. The Fund will return any payment received for orders that have been cancelled, but no interest will be paid on that money.

■ Financial intermediaries are responsible for sending your purchase orders to the Transfer Agent and ensuring that the Fund receives your money on time.

■ Shares purchased are recorded on the books of the Fund. The Fund does not issue certificates.

■ You generally may make a purchase only into a Fund that is accepting investments.

Please also read Appendix A and contact your financial intermediary for more information regarding any reductions and/or waivers described therein.

Selling Shares

When you sell shares, the amount you receive may be more or less than the amount you invested. Your sale price will be the next NAV calculated after your request is received in “good form,” (i.e., the trade date) minus any applicable CDSC.

Systematic Withdrawal Plan

The Systematic Withdrawal Plan allows you to schedule regular redemptions from your account any business day on a monthly, quarterly or semiannual basis. Currently, Systematic Withdrawal Plans are generally available for Class A, Class Adv, Class C, Class Inst, Class Inst2, and Class Inst3 share accounts. Contact the Transfer Agent or your financial intermediary to set up the plan. To set up the plan, your account balance must meet the class minimum initial investment amount. A Systematic Withdrawal Plan cannot be set up on an account that already has a Systematic Investment Plan established. Note that a Medallion Signature Guarantee may be required if this service is established after your Fund account is opened.

You can choose to receive your withdrawals via check or direct deposit into your bank account. The Fund will deduct any applicable CDSC from the withdrawals before sending redemption proceeds to you. You can cancel the plan by giving the Fund 30 days’ notice in writing or by calling the Transfer Agent at 800.422.3737. It’s important to remember that if you withdraw more than your investment in the Fund is earning, you'll eventually withdraw your entire investment.

Satisfying Fund Redemption Requests

When you sell your Fund shares, the Fund is effectively buying them back from you. This is called a redemption. Except as noted below with respect to newly purchased shares, the Fund typically expects to send you payment for your shares within two business days after your trade date. The Fund can suspend redemptions and/or delay

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Buying, Selling and Exchanging Shares (continued)

payment of redemption proceeds for up to seven days. The Fund can also suspend redemptions and/or delay payment of redemption proceeds in excess of seven days under certain circumstances, including when the NYSE is closed or trading thereon is restricted or during emergency or other circumstances, including as determined by the SEC.

The Fund typically seeks to satisfy redemption requests from cash or cash equivalents held by the Fund, from the proceeds of orders to purchase Fund shares or from the proceeds of sales of Fund holdings effected in the normal course of managing the Fund. However, the Fund may have to sell Fund holdings, including in down markets, to meet heavier than usual redemption requests. For example, under stressed or abnormal market conditions or circumstances, including circumstances adversely affecting the liquidity of the Fund’s investments, the Fund may be more likely to be forced to sell Fund holdings to meet redemptions than under normal market circumstances. In these situations, the Fund’s portfolio managers may have to sell Fund holdings that would not otherwise be sold because, among other reasons, the current price to be received is less than the value of the holdings perceived by the Fund’s portfolio managers. The Fund may also, under certain circumstances (likely under stressed or abnormal market conditions or circumstances), borrow money under a credit facility to which the Fund and certain other Columbia Funds are parties. The Fund and the other Columbia Funds are limited as to the amount that each may individually and collectively borrow under the credit facility. As a result, borrowings available to the Fund under the credit facility might be insufficient, alone or in combination with the other strategies described herein, to satisfy Fund redemption requests. Please see About Fund Investments – Borrowings in the SAI for more information about the credit facility. The Fund is also limited in the total amount it may borrow. Please see About Fund Investments – Fundamental and Non-Fundamental Investment Policies in the SAI for more information about borrowing.

In addition, the Fund reserves the right to honor redemption orders in whole or in part with in-kind distributions of Fund portfolio securities instead of cash. Such in-kind distributions typically represent a pro-rata portion of Fund portfolio assets subject to adjustments (e.g., for non-transferable securities, round lots, and derivatives, if any). In the event the Fund distributes portfolio securities in kind, you may incur brokerage and other transaction costs associated with converting the portfolio securities you receive into cash. Also, the portfolio securities you receive may increase or decrease in value after they are distributed but before you convert them into cash. For U.S. federal income tax purposes, redemptions paid in securities are generally treated the same as redemptions paid in cash. The Trust has elected to be governed by Rule 18f-1 under the 1940 Act, which means that for each redeeming shareholder, the first $250,000, or 1% of the Fund's net asset value, whichever is less, will be paid in cash or cash equivalents and the remainder may be paid in kind.

While the Fund is not required (and may refuse in its discretion) to pay a redemption with an in-kind distribution of Fund portfolio securities and reserves the right to pay the redemption proceeds in cash, if you wish to request an in-kind redemption, please call the Transfer Agent at 800.345.6611. As a result of the operational steps needed to coordinate with the redeeming shareholder’s custodian, in-kind redemptions typically take several weeks to complete after a redemption request is received. The Fund and the redeeming shareholder will typically agree upon a redemption date. Since the Fund’s NAV may fluctuate during this time, the Fund’s NAV may be lower on the agreed-upon redemption date than on an earlier date on which the investment could have been redeemed for cash.

Redemption of Newly Purchased Shares

You may not redeem shares for which the Fund has not yet received payment. Shares purchased by check or electronically by ACH when the purchase payment is not guaranteed will be considered in “good form” for redemption only after they have been held in your account for 6 calendar days after the trade date of the purchase (Collected Shares). If you request a redemption for an amount that, based on the NAV next calculated after your redemption request is received, includes any shares that are not yet Collected Shares, the Fund will only process the redemption up to the amount of the value of Collected Shares available in your account. You must submit a new redemption request if you wish to redeem those shares that were not yet Collected Shares at the time the original redemption request was received by the Fund.

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Columbia Acorn European Fund^SM

Buying, Selling and Exchanging Shares (continued)

Other Redemption Rules You Should Know

■ Once the Transfer Agent or your financial intermediary receives your redemption order in “good form,” your shares will be sold at the Fund’s next calculated NAV per share (i.e., the trade date). Any applicable CDSC will be deducted from the amount you're selling and the balance will be remitted to you.

■ Once the Fund receives your redemption request in “good form,” you cannot cancel it after the market closes.

■ The Distributor, in its sole discretion, reserves the right to liquidate Fund shares (of any class of the Fund) held in an omnibus account of a financial intermediary that clears Fund share transactions through a clearing intermediary or platform that charges certain maintenance fees to the Fund if the value of the omnibus account, at the Fund share class (i.e., CUSIP) level, falls below $100,000 (a CUSIP Liquidation Event). The Distributor will provide at least 90 days’ notice of a CUSIP Liquidation Event to financial intermediaries with impacted omnibus accounts. Shareholders invested in the Fund through such omnibus accounts can request through their financial intermediary a tax-free exchange to Class A shares or shareholders can consider holding their Fund shares in a Direct-at-Fund Account, provided requirements to transfer the account are fulfilled. You should discuss your options with your financial intermediary.

■ If you sell your shares that are held in a Direct-at-Fund Account, we will normally send the redemption proceeds by mail or electronically transfer them to your bank account the next business day after the trade date. Note that your bank may take up to three business days to post an electronic funds transfer from your account.

■ If you sell your shares through a financial intermediary, the Funds will normally send the redemption proceeds to your financial intermediary within two business days after the trade date.

■ No interest will be paid on uncashed redemption checks.

■ Other restrictions may apply to retirement accounts. For information about these restrictions, contact your retirement plan administrator.

■ For broker-dealer and wrap fee accounts: The Fund reserves the right to redeem your shares if your account falls below the Fund's minimum initial investment requirement. The Fund will notify your broker-dealer prior to redeeming shares, and will provide details on how to avoid such redemption.

■ Also keep in mind the Funds' Small Account Policy, which is described above in Buying, Selling and Exchanging Shares — Transaction Rules and Policies.

Exchanging Shares

You can generally sell shares of your Fund to buy shares of another Fund (subject to eligibility requirements), in what is called an exchange. You should read the prospectus of, and make sure you understand the investment objective, principal investment strategies, risks, fees and expenses of, the Fund into which you are exchanging. Although the Funds allow certain exchanges from one share class to another share class with higher expenses, you should consider the expenses of each class before making such an exchange. Please see Same-Fund Exchange Privilege below for more information.

You will be subject to a sales charge if, in a Direct-at-Fund Account, you exchange shares that have not previously paid a sales charge, including from Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia U.S. Treasury Index Fund or any other Columbia Fund that does not charge a front-end sales charge, into a Columbia Fund that does assess a sales charge. If you hold your Fund shares through certain financial intermediaries, you may have limited exchangeability among the Funds. Please contact your financial intermediary for more information.

Systematic Exchanges

You may buy Class A, Class C, Class Inst and Class Inst3 shares of a Fund by exchanging each month from another Fund for shares of the same class of the Fund at no additional cost, subject to the following exchange amount minimums: $50 each month for individual retirement accounts (i.e., tax qualified accounts); and $100 each month for non-retirement accounts. Contact the Transfer Agent or your financial intermediary to set up the plan.

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Buying, Selling and Exchanging Shares (continued)

Exchanges will continue as long as your balance in the Fund you are exchanging shares from is sufficient to complete the systematic monthly exchange, subject to the Funds' Small Account Policy described above in Buying, Selling and Exchanging Shares — Transaction Rules and Policies. You may terminate the program or change the amount you would like to exchange (subject to the $50 and $100 minimum requirements noted immediately above) by calling the Transfer Agent at 800.345.6611.

Other Exchange Rules You Should Know

■ Exchanges are made at the NAV next calculated (plus any applicable sales charge) after your exchange order is received in “good form” (i.e., the trade date).

■ Once the Fund receives your exchange request in “good form,” you cannot cancel it after the market closes.

■ The rules for buying shares of a Fund generally apply to exchanges into that Fund, including, if your exchange creates a new Fund account, it must satisfy the minimum investment amount, unless a waiver applies.

■ Shares of the purchased Fund may not be used on the same day for another exchange or sale.

■ If you exchange shares from Class A shares of Columbia Government Money Market Fund to a non-money market Fund, any further exchanges must be between shares of the same class. For example, if you exchange from Class A shares of Columbia Government Money Market Fund into Class C shares of a non-money market Fund, you may not exchange from Class C shares of that non-money market Fund back to Class A shares of Columbia Government Money Market Fund or Class A shares of any other Fund.

■ A sales charge may apply when you exchange shares of a Fund that were not assessed a sales charge at the time you purchased such shares. If you invest through a Direct-at-Fund Account in Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund, Columbia U.S. Treasury Index Fund or any other Columbia Fund that does not impose a front-end sales charge and then you exchange into a Fund that does assess a sales charge, your transaction is subject to a front-end sales charge if you exchange into Class A shares and to a CDSC if you exchange into Class C shares of the Columbia Funds.

■ If you purchased Class A shares of a Columbia Fund that imposes a front-end sales charge (and you paid any applicable sales charge) and you then exchange those shares into Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund, Columbia U.S. Treasury Index Fund or any other Columbia Fund that does not impose a front-end sales charge, you may exchange that amount to Class A of another Fund in the future, including dividends earned on that amount, without paying a sales charge.

■ If your shares are subject to a CDSC, you will not be charged a CDSC upon the exchange of those shares. Any CDSC will be deducted when you sell the shares you received from the exchange. The CDSC imposed at that time will be based on the period that begins when you bought shares of the original Fund and ends when you sell the shares of the Fund you received from the exchange. Any applicable CDSC charged will be the CDSC of the original Fund.

■ You may make exchanges only into a Fund that is legally offered and sold in your state of residence. Contact the Transfer Agent or your financial intermediary for more information.

■ You generally may make an exchange only into a Fund that is accepting investments.

■ The Fund may change or cancel your right to make an exchange by giving the amount of notice required by regulatory authorities (generally 60 days for a material change or cancellation).

■ Unless your account is part of a tax-advantaged arrangement, an exchange for shares of another Fund is a taxable event, and you may recognize a gain or loss for tax purposes.

■ Changing your investment to a different Fund will be treated as a sale and purchase, and you will be subject to applicable taxes on the sale and sales charges on the purchase of the new Fund.

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Columbia Acorn European Fund^SM

Buying, Selling and Exchanging Shares (continued)

■ Class Inst shares of a Fund may be exchanged for Class A or Class Inst shares of another Fund. In certain circumstances, the front-end sales charge applicable to Class A shares may be waived on exchanges of Class Inst shares for Class A shares. See Buying, Selling and Exchanging Shares — Buying Shares — Eligible Investors — Class Inst Shares for details.

Same-Fund Exchange Privilege

Shareholders may be eligible to invest in other classes of shares of the same Fund, and may exchange their current shares for another share class if deemed eligible and offered by the Fund. Such same-Fund exchanges could include an exchange of one class for another with higher expenses. Before making such an exchange, you should consider the expenses of each class. Shareholders should contact their financial intermediaries to learn more about the details of the same-Fund exchange privilege. Exchanges out of Class A and Class C shares will be subject to any applicable CDSC. Financial intermediaries that have a customized arrangement with regard to CDSCs are detailed in Appendix A.

Exchanges out of Class C shares to another share class of the same Fund are not permissible on Direct-at-Fund Accounts, except that the Transfer Agent seeks to convert Class C shares as soon as administratively feasible to Class A shares of the same Fund for Direct-at-Fund Accounts that do not or no longer have a financial intermediary assigned to them. Direct-at-Fund Accounts that do not have a financial intermediary assigned to them are not permitted to purchase Class C shares. Class C share purchase orders received by Direct-at-Fund Accounts that do not have a financial intermediary assigned to the account will automatically be invested in Class A shares of the same Fund. Exchanges out of Class C shares to another share class of the same Fund within commissionable brokerage accounts are permitted only (1) when the shareholder moves from a commissionable brokerage account to a fee-based advisory program or (2) when the exchange is part of a share class conversion (or a similar multiple shareholder transaction event) instituted by a financial intermediary and such conversion or similar type event is preapproved by the Distributor.

Ordinarily, shareholders will not recognize a gain or loss for U.S. federal income tax purposes upon a same-Fund exchange. You should consult your tax advisor about your particular exchanges.

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Columbia Acorn European Fund^SM

Distributions and Taxes

Distributions to Shareholders

A mutual fund can make money two ways:

■ It can earn income on its investments. Examples of fund income are interest paid on money market instruments and bonds, and dividends paid on common stocks.

■ A mutual fund can also have capital gains if the value of its investments increases. While a fund continues to hold an investment, any gain is generally unrealized. If the fund sells an investment, it generally will realize a capital gain if it sells that investment for a higher price than its adjusted cost basis, and will generally realize a capital loss if it sells that investment for a lower price than its adjusted cost basis. Capital gains and losses are either short-term or long-term, depending on whether the fund holds the securities for one year or less (short-term) or more than one year (long-term).

Mutual funds make payments of fund earnings to shareholders, distributing them among all shareholders of the fund. As a shareholder, you are entitled to your portion of a fund's distributed income, including capital gains. Reinvesting your distributions buys you more shares of a fund — which lets you take advantage of the potential for compound growth. Putting the money you earn back into your investment means it, in turn, may earn even more money (or be exposed to additional losses, if the Fund earns a negative return). Over time, the power of compounding has the potential to significantly increase the value of your investment. There is no assurance, however, that you'll earn more money if you reinvest your distributions rather than receive them in cash.

The Fund intends to pay out, in the form of distributions to shareholders, a sufficient amount of its income and gains so that the Fund will qualify for treatment as a regulated investment company and generally will not have to pay any federal excise tax. The Fund generally intends to distribute any net realized capital gain (whether long-term or short-term gain) at least once a year. Normally, the Fund will declare and pay distributions of net investment income according to the following schedule:

Declaration and Distribution Schedule
Declarations	Semiannually
Distributions	Semiannually

The Fund may declare or pay distributions of net investment income more frequently.

Different share classes of the Fund usually pay different net investment income distribution amounts, because each class has different expenses. Each time a distribution is made, the NAV per share of the share class is reduced by the amount of the distribution.

The Fund generally pays cash distributions within five business days after the distribution was declared (or, if the Fund declares distributions daily, within five business days after the end of the month in which the distribution was declared). If you sell all of your shares after the record date, but before the payment date, for a distribution, you'll normally receive that distribution in cash within five business days after the sale was made.

The Fund will automatically reinvest distributions in additional shares of the same share class of the Fund unless you inform us you want to receive your distributions in cash (the financial intermediary through which you purchased shares may have different policies). You can do this by contacting the Funds at the addresses and telephone numbers listed at the beginning of the section entitled Choosing a Share Class. No sales charges apply to the purchase or sale of such shares.

For accounts held directly with the Fund (through the Transfer Agent), distributions of $10 or less will automatically be reinvested in additional Fund shares only. If you elect to receive distributions by check and the check is returned as undeliverable, all subsequent distributions will be reinvested in additional shares of the Fund.

Unless you are a tax-exempt investor or holding Fund shares through a tax-advantaged account (such as a 401(k) plan or IRA), you should consider avoiding buying Fund shares shortly before the Fund makes a distribution (other than distributions of net investment income that are declared daily) of net investment income or net realized capital gain, because doing so can cost you money in taxes to the extent the distribution consists of taxable income or gains. This is because you will, in effect, receive part of your purchase price back in the distribution. This is known as

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Columbia Acorn European Fund^SM

Distributions and Taxes (continued)

“buying a dividend.” To avoid “buying a dividend,” before you invest check the Fund's distribution schedule, which is available at the Funds' website and/or by calling the Funds' telephone number listed at the beginning of the section entitled Choosing a Share Class.

Taxes

You should be aware of the following considerations applicable to the Fund:

■ The Fund intends to qualify and to be eligible for treatment each year as a regulated investment company. A regulated investment company generally is not subject to tax at the fund level on income and gains from investments that are distributed to shareholders. However, the Fund's failure to qualify for treatment as a regulated investment company would result in Fund-level taxation, and consequently, a reduction in income available for distribution to you and in the NAV of your shares. Even if the Fund qualifies for treatment as a regulated investment company, the Fund may be subject to federal excise tax on certain undistributed income or gains.

■ Otherwise taxable distributions generally are taxable to you when paid, whether they are paid in cash or automatically reinvested in additional Fund shares. Dividends paid in January are deemed paid on December 31 of the prior year if the dividend was declared and payable to shareholders of record in October, November, or December of such prior year.

■ Distributions of the Fund's ordinary income and net short-term capital gain, if any, generally are taxable to you as ordinary income. Distributions of the Fund's net long-term capital gain, if any, generally are taxable to you as long-term capital gain. Whether capital gains are long-term or short-term is determined by how long the Fund has owned the investments that generated them, rather than how long you have owned your shares. Certain events may require the Fund to sell significant amounts of appreciated securities, and make large capital gain dividends relative to the Fund’s NAV. Such events may include large net shareholder redemptions, portfolio re-balancing or fund mergers. The Fund generally provides estimates of expected capital gain dividends (if any) prior to the distribution on columbiathreadneedleus.com.

■ From time to time, a distribution from the Fund could constitute a return of capital. A return of capital is a return of an amount of your original investment and is not a distribution of income or capital gain from the Fund. Therefore, a return of capital is not taxable to you so long as the amount of the distribution does not exceed your tax basis in your Fund shares. A return of capital reduces your tax basis in your Fund shares, with any amounts exceeding such basis generally taxable as capital gain.

■ If you are an individual and you meet certain holding period and other requirements for your Fund shares, a portion of your distributions may be treated as “qualified dividend income” taxable at the lower net long-term capital gain rates instead of the higher ordinary income rates. Qualified dividend income is income attributable to the Fund's dividends received from certain U.S. and foreign corporations, as long as the Fund meets certain holding period and other requirements for the stock producing such dividends.

■ Certain high-income individuals (as well as estates and trusts) are subject to a 3.8% tax on net investment income. For individuals, the 3.8% tax applies to the lesser of (1) the amount (if any) by which the taxpayer's modified adjusted gross income exceeds certain threshold amounts or (2) the taxpayer's “net investment income.”

■ Certain derivative instruments when held in the Fund's portfolio subject the Fund to special tax rules, the effect of which may be to, among other things, accelerate income to the Fund, defer Fund losses, cause adjustments in the holding periods of Fund portfolio securities, or convert capital gains into ordinary income, short-term capital losses into long-term capital losses or long-term capital gains into short-term capital gains. These rules could therefore affect the amount, timing and/or character of distributions to shareholders.

■ Generally, a Fund realizes a capital gain or loss on an option when the option expires, or when it is exercised, sold or otherwise terminated. However, if an option is a “section 1256 contract,” which includes most traded options on a broad-based index, and the Fund holds such option at the end of its taxable year, the Fund is deemed to sell such option at fair market value at such time and recognize any gain or loss thereon, which is generally deemed to be 60% long-term and 40% short-term capital gain or loss, as described further in the SAI.

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Columbia Acorn European Fund^SM

Distributions and Taxes (continued)

■ Income and proceeds received by the Fund from sources within foreign countries may be subject to foreign taxes. If at the end of the taxable year more than 50% of the value of the Fund's assets consists of securities of foreign corporations, and the Fund makes a special election, you will generally be required to include in your income for U.S. federal income tax purposes your share of the qualifying foreign income taxes paid by the Fund in respect of its foreign portfolio securities. You may be able to claim a foreign tax credit or deduction in respect of this amount, subject to certain limitations. There is no assurance that the Fund will make this election for a taxable year, even if it is eligible to do so.

■ A sale, redemption or exchange of Fund shares is a taxable event. This includes redemptions where you are paid in securities. Your sales, redemptions and exchanges of Fund shares (including those paid in securities) usually will result in a taxable capital gain or loss to you, equal to the difference between the amount you receive for your shares (or are deemed to have received in the case of exchanges) and your adjusted tax basis in the shares, which is generally the amount you paid (or are deemed to have paid in the case of exchanges) for them. Any such capital gain or loss generally will be long-term capital gain or loss if you have held your Fund shares for more than one year at the time of sale or exchange. In certain circumstances, capital losses may be converted from short-term to long-term; in other circumstances, capital losses may be disallowed under the “wash sale” rules.

■ For sales, redemptions and exchanges of shares that were acquired in a non-qualified account after 2011, the Fund generally is required to report to shareholders and the Internal Revenue Service (IRS) cost basis information with respect to those shares. The Fund uses average cost basis as its default method of calculating cost basis. For more information regarding average cost basis reporting, other available cost basis methods, and selecting or changing to a different cost basis method, please see the SAI, columbiathreadneedleus.com, or contact the Fund at 800.345.6611. If you hold Fund shares through a financial intermediary (e.g., a brokerage firm), you should contact your financial intermediary to learn about its cost basis reporting default method and the reporting elections available to your account.

■ The Fund is required by federal law to withhold tax on any taxable or tax-exempt distributions and redemption proceeds paid to you (including amounts paid to you in securities and amounts deemed to be paid to you upon an exchange of shares) if: you have not provided a correct TIN or have not certified to the Fund that withholding does not apply, the IRS has notified us that the TIN listed on your account is incorrect according to its records, or the IRS informs the Fund that you are otherwise subject to backup withholding.

 FUNDamentals

Taxes

The information provided above is only a summary of how U.S. federal income taxes may affect your investment in the Fund. It is not intended as a substitute for careful tax planning. Your investment in the Fund may have other tax implications. It does not apply to certain types of investors who may be subject to special rules, including foreign or tax-exempt investors or those holding Fund shares through a tax-advantaged account, such as a 401(k) plan or IRA. Please see the SAI for more detailed tax information. You should consult with your own tax advisor about the particular tax consequences to you of an investment in the Fund, including the effect of any foreign, state and local taxes, and the effect of possible changes in applicable tax laws.

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Columbia Acorn European Fund^SM

Financial Highlights

The financial highlights table is intended to help you understand the Fund’s financial performance for the past five fiscal years. Certain information reflects financial results for a single Fund share. Per share net investment income (loss) amounts are calculated based on average shares outstanding during the period. The total return in the table represents the rate that an investor would have earned (or lost) on an investment in the Fund assuming all dividends and distributions had been reinvested. Total return does not reflect payment of sales charges, if any. Total return and portfolio turnover are not annualized for periods of less than one year. The portfolio turnover rate is calculated without regard to purchase and sales transactions of short-term instruments and certain derivatives, if any. If such transactions were included, the Fund’s portfolio turnover rate might be higher. The names of certain share classes may have changed during the periods shown below (see Appendix S to the SAI for details). This information has been audited by PricewaterhouseCoopers LLP, an independent registered public accounting firm, whose report, along with the Fund’s financial statements, is included in the Fund’s annual report, which is available upon request. The independent registered public accounting firm’s report and the Fund’s financial statements are also incorporated by reference into the SAI.

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Columbia Acorn European Fund^SM

Financial Highlights (continued)

	Net asset value, beginning of period	Net investment income (loss)	Net realized and unrealized gain (loss)	Total from investment operations	Distributions from net investment income	Total distributions to shareholders
Class A
Year Ended 12/31/2021	$27.49	(0.14)	6.04	5.90	(0.06)	(0.06)
Year Ended 12/31/2020	$22.52	(0.12)	5.22	5.10	(0.13)	(0.13)
Year Ended 12/31/2019	$15.56	0.06	7.09	7.15	(0.19)	(0.19)
Year Ended 12/31/2018	$19.27	0.11	(3.70)	(3.59)	(0.12)	(0.12)
Year Ended 12/31/2017	$14.12	0.06	5.28	5.34	(0.19)	(0.19)
Advisor Class
Year Ended 12/31/2021	$27.78	(0.10)	6.13	6.03	(0.13)	(0.13)
Year Ended 12/31/2020	$22.70	(0.06)	5.27	5.21	(0.13)	(0.13)
Year Ended 12/31/2019	$15.68	0.12	7.13	7.25	(0.23)	(0.23)
Year Ended 12/31/2018	$19.36	0.19	(3.75)	(3.56)	(0.12)	(0.12)
Year Ended 12/31/2017	$14.18	0.10	5.32	5.42	(0.24)	(0.24)
Class C
Year Ended 12/31/2021	$26.83	(0.36)	5.88	5.52	—	—
Year Ended 12/31/2020	$22.15	(0.27)	5.08	4.81	(0.13)	(0.13)
Year Ended 12/31/2019	$15.33	(0.06)	6.93	6.87	(0.05)	(0.05)
Year Ended 12/31/2018	$19.12	(0.02)	(3.65)	(3.67)	(0.12)	(0.12)
Year Ended 12/31/2017	$13.99	(0.04)	5.21	5.17	(0.04)	(0.04)
Institutional Class
Year Ended 12/31/2021	$27.64	(0.06)	6.06	6.00	(0.13)	(0.13)
Year Ended 12/31/2020	$22.59	(0.06)	5.24	5.18	(0.13)	(0.13)
Year Ended 12/31/2019	$15.60	0.12	7.10	7.22	(0.23)	(0.23)
Year Ended 12/31/2018	$19.27	0.15	(3.70)	(3.55)	(0.12)	(0.12)
Year Ended 12/31/2017	$14.11	0.14	5.26	5.40	(0.24)	(0.24)
Institutional 2 Class
Year Ended 12/31/2021	$27.98	(0.12)	6.21	6.09	(0.15)	(0.15)
Year Ended 12/31/2020	$22.84	(0.05)	5.32	5.27	(0.13)	(0.13)
Year Ended 12/31/2019	$15.78	0.14	7.17	7.31	(0.25)	(0.25)
Year Ended 12/31/2018	$19.46	0.19	(3.75)	(3.56)	(0.12)	(0.12)
Year Ended 12/31/2017	$14.25	0.20	5.25	5.45	(0.24)	(0.24)

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Financial Highlights (continued)

	Net asset value, end of period	Total return(a)	Total gross expense ratio to average net assets(b)	Total net expense ratio to average net assets(b)	Net investment income (loss) ratio to average net assets	Portfolio turnover	Net assets, end of period (000's)
Class A
Year Ended 12/31/2021	$33.33	21.47%	1.63% (c)	1.44% (c), (d)	(0.45%)	21%	$66,374
Year Ended 12/31/2020	$27.49	22.80%	1.86% (c)	1.45% (c)	(0.54%)	45%	$42,059
Year Ended 12/31/2019	$22.52	45.96%	1.88%	1.44%	0.33%	30%	$33,361
Year Ended 12/31/2018	$15.56	(18.78%)	1.81% (c)	1.45% (c)	0.57%	39%	$22,870
Year Ended 12/31/2017	$19.27	37.89%	1.94%	1.58% (d)	0.33%	34%	$32,487
Advisor Class
Year Ended 12/31/2021	$33.68	21.75%	1.37% (c)	1.19% (c), (d)	(0.32%)	21%	$3,083
Year Ended 12/31/2020	$27.78	23.10%	1.61% (c)	1.20% (c)	(0.29%)	45%	$1,781
Year Ended 12/31/2019	$22.70	46.30%	1.63%	1.19%	0.60%	30%	$1,906
Year Ended 12/31/2018	$15.68	(18.53%)	1.55% (c)	1.19% (c)	0.97%	39%	$1,496
Year Ended 12/31/2017	$19.36	38.29%	1.71%	1.28% (d)	0.55%	34%	$2,942
Class C
Year Ended 12/31/2021	$32.35	20.57%	2.39% (c)	2.19% (c), (d)	(1.20%)	21%	$7,078
Year Ended 12/31/2020	$26.83	21.87%	2.61% (c)	2.20% (c)	(1.27%)	45%	$5,705
Year Ended 12/31/2019	$22.15	44.79%	2.64%	2.19%	(0.30%)	30%	$6,186
Year Ended 12/31/2018	$15.33	(19.34%)	2.56% (c)	2.20% (c)	(0.12%)	39%	$8,770
Year Ended 12/31/2017	$19.12	36.95%	2.69%	2.31% (d)	(0.25%)	34%	$13,965
Institutional Class
Year Ended 12/31/2021	$33.51	21.76%	1.38% (c)	1.19% (c), (d)	(0.21%)	21%	$111,462
Year Ended 12/31/2020	$27.64	23.08%	1.61% (c)	1.20% (c)	(0.29%)	45%	$55,171
Year Ended 12/31/2019	$22.59	46.35%	1.63%	1.19%	0.64%	30%	$49,616
Year Ended 12/31/2018	$15.60	(18.57%)	1.56% (c)	1.20% (c)	0.80%	39%	$32,813
Year Ended 12/31/2017	$19.27	38.35%	1.69%	1.29% (d)	0.77%	34%	$48,965
Institutional 2 Class
Year Ended 12/31/2021	$33.92	21.80%	1.32% (c)	1.14% (c)	(0.38%)	21%	$25,882
Year Ended 12/31/2020	$27.98	23.23%	1.58% (c)	1.14% (c)	(0.24%)	45%	$3,855
Year Ended 12/31/2019	$22.84	46.33%	1.60%	1.13%	0.73%	30%	$2,175
Year Ended 12/31/2018	$15.78	(18.44%)	1.50% (c)	1.13% (c)	0.96%	39%	$2,554
Year Ended 12/31/2017	$19.46	38.32%	1.64%	1.28%	1.14%	34%	$3,988

Prospectus 2022 67

Columbia Acorn European Fund^SM

Financial Highlights (continued)

	Net asset value, beginning of period	Net investment income (loss)	Net realized and unrealized gain (loss)	Total from investment operations	Distributions from net investment income	Total distributions to shareholders
Institutional 3 Class
Year Ended 12/31/2021	$27.54	(0.05)	6.05	6.00	(0.16)	(0.16)
Year Ended 12/31/2020	$22.48	(0.02)	5.21	5.19	(0.13)	(0.13)
Year Ended 12/31/2019	$15.53	0.14	7.06	7.20	(0.25)	(0.25)
Year Ended 12/31/2018	$19.17	(0.04)	(3.48)	(3.52)	(0.12)	(0.12)
Year Ended 12/31/2017(e)	$15.02	0.03	4.40	4.43	(0.28)	(0.28)

Notes to Financial Highlights
(a)	Had the Investment Manager and/or Transfer Agent not waived fees and/or reimbursed a portion of expenses, total return would have been reduced.
(b)	In addition to the fees and expenses that the Fund bears directly, the Fund indirectly bears a pro rata share of the fees and expenses of any other funds in which it invests, if any. Such indirect expenses are not included in the Fund's reported expense ratios.
(c)	Ratios include line of credit interest expense which is less than 0.01%.
(d)	The benefits derived from expense reductions had an impact of less than 0.01%.
(e)	Institutional 3 Class shares commenced operations on March 1, 2017. Per share data and total return reflect activity from that date.
(f)	Annualized.

68 Prospectus 2022

Columbia Acorn European Fund^SM

Financial Highlights (continued)

	Net asset value, end of period	Total return(a)	Total gross expense ratio to average net assets(b)	Total net expense ratio to average net assets(b)	Net investment income (loss) ratio to average net assets	Portfolio turnover	Net assets, end of period (000's)
Institutional 3 Class
Year Ended 12/31/2021	$33.38	21.83%	1.32% (c)	1.10% (c)	(0.15%)	21%	$60
Year Ended 12/31/2020	$27.54	23.24%	1.52% (c)	1.10% (c)	(0.08%)	45%	$69
Year Ended 12/31/2019	$22.48	46.42%	1.54%	1.09%	0.74%	30%	$19
Year Ended 12/31/2018	$15.53	(18.51%)	1.41% (c)	1.08% (c)	(0.21%)	39%	$3
Year Ended 12/31/2017(e)	$19.17	29.55%	1.58% (f)	1.09% (f)	0.17% (f)	34%	$210

Prospectus 2022 69

Columbia Acorn European Fund^SM

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges

As noted in the Choosing a Share Class section of the prospectus, the sales charge reductions and waivers available to investors who purchase and hold their Fund shares through different financial intermediaries may vary. This Appendix A describes financial intermediary-specific reductions and/or waiver policies applicable to Fund shares purchased and held through the particular financial intermediary. A reduction and/or waiver that is specific to a particular financial intermediary is not available to Direct-at-Fund Accounts and does not apply in any case to non-omnibus positions wherever held. These reductions and/or waivers may apply to purchases, sales, and exchanges of Fund shares. A shareholder transacting in Fund shares through a financial intermediary identified below should carefully read the terms and conditions of the reductions and/or waivers. Please consult your financial intermediary with respect to any sales charge reduction/waiver described below.

The financial intermediary-specific information below may be provided by, or compiled from or based on information provided by, the financial intermediaries noted. While the Funds, the Investment Manager and the Distributor do not establish these financial intermediary-specific policies, our representatives are available to answer questions about these financial intermediary-specific policies and can direct you to the financial intermediary if you need help understanding them.

 Ameriprise Financial Services, LLC (Ameriprise Financial Services)

The following information has been provided by Ameriprise Financial Services:

Class A Shares Front-End Sales Charge Waivers Available at Ameriprise Financial Services:

The following information applies to Class A shares purchases if you have an account with or otherwise purchase Fund shares through Ameriprise Financial Services:

Shareholders purchasing Fund shares through an Ameriprise Financial Services brokerage account are eligible for the following front-end sales charge waivers, which may differ from those disclosed elsewhere in this prospectus or the Fund’s SAI:

■ Employer-sponsored retirement plans (e.g., 401(k) plans, 457 plans, employer-sponsored 403(b) plans, profit sharing and money purchase pension plans and defined benefit plans). For purposes of this provision, employer-sponsored retirement plans do not include SEP IRAs, Simple IRAs or SAR-SEPs.

■ Shares purchased through reinvestment of capital gains distributions and dividend reinvestment when purchasing shares of the same fund (but not any other fund within the Columbia Fund family).

■ Shares exchanged from Class C shares of the same fund in the month of or following the 7-year anniversary of the purchase date. To the extent that the Fund’s Class C Shares – Conversion to Class A Shares policy (stated outside this Appendix A) provides for a waiver with respect to exchanges of Class C shares or the conversion of Class C shares following a shorter holding period, that waiver will apply.

■ Employees and registered representatives of Ameriprise Financial Services or its affiliates and their immediate family members.

■ Shares purchased by or through qualified accounts (including IRAs, Coverdell Education Savings Accounts, 401(k)s, 403(b) TSCAs subject to ERISA and defined benefit plans) that are held by a covered family member, defined as an Ameriprise financial advisor and/or the advisor’s spouse, advisor’s lineal ascendant (mother, father, grandmother, grandfather, great grandmother, great grandfather), advisor’s lineal descendant (son, step-son, daughter, step-daughter, grandson, granddaughter, great grandson, great granddaughter) or any spouse of a covered family member who is a lineal descendant.

■ Shares purchased from the proceeds of redemptions from another fund in the Columbia Fund family, provided (1) the repurchase occurs within 90 days following the redemption, (2) the redemption and purchase occur in the same account, and (3) redeemed shares were subject to a front-end or deferred sales load (i.e. Rights of Reinstatement).

A-1 Prospectus 2022

Columbia Acorn European Fund^SM

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

 Robert W. Baird & Co. Incorporated (Baird)

The following information has been provided by Baird:

Effective June 30, 2020, shareholders purchasing Columbia Fund shares through a Baird platform or account that maintains an omnibus position with the Fund will only be eligible for the following sales charge waivers (front-end sales charge waivers and CDSC waivers) and discounts, which may differ from those disclosed elsewhere in this prospectus or the Fund’s SAI. A reduction and/or waiver that is specific to Baird will not apply to non-omnibus positions.

Front-End Sales Charge Waivers on Class A Shares Available at Baird:

■ Shares purchased through reinvestment of capital gains distributions and dividend reinvestment when purchasing shares of the same Columbia Fund.

■ Share purchases by employees and registered representatives of Baird or its affiliates and their family members as designated by Baird.

■ Shares purchased with the proceeds of redemptions from another Columbia Fund, provided (1) the repurchase occurs within 90 days following the redemption, (2) the redemption and purchase occur in the same accounts, and (3) redeemed shares were subject to a front-end or deferred sales charge (known as rights of reinstatement).

■ A shareholder in the Fund’s Class C shares will have their shares converted at net asset value to Class A shares of the same Columbia Fund if the shares are no longer subject to CDSC and the conversion is in line with the policies and procedures of Baird.

■ Employer-sponsored retirement plans or charitable accounts in a transactional brokerage account at Baird, including 401(k) plans, 457 plans, employer-sponsored 403(b) plans, profit sharing and money purchase pension plans and defined benefit plans. For purposes of this provision, employer-sponsored retirement plans do not include SEP IRAs, Simple IRAs or SAR-SEPs.

CDSC Waivers on Class A and Class C Shares Available at Baird:

■ Shares sold due to death or disability of the shareholder.

■ Shares sold as part of a systematic withdrawal plan as described in this prospectus.

■ Shares purchased due to returns of excess contributions from an IRA account.

■ Shares sold as part of a required minimum distribution for IRA and retirement accounts due to the shareholder reaching the qualified age based on applicable IRS regulations.

■ Shares sold to pay Baird fees but only if the transaction is initiated by Baird.

■ Shares acquired through a right of reinstatement.

Front-End Sales Charge Discounts Available at Baird: Breakpoints and/or Rights of Accumulations:

■ Breakpoints as described in this prospectus.

■ Rights of accumulations which entitle shareholders to breakpoint discounts will be automatically calculated based on the aggregated holding of Columbia Fund assets held by accounts within the purchaser’s household at Baird. Eligible Columbia Fund assets not held at Baird may be included in the rights of accumulations calculation only if the shareholder notifies his or her financial advisor about such assets.

■ Letters of Intent (LOI) allow for breakpoint discounts based on anticipated purchases of Columbia Funds through Baird, over a 13-month period of time.

Prospectus 2022 A-2

Columbia Acorn European Fund^SM

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

 Edward D. Jones & Co., L.P. (Edward Jones)

Policies Regarding Transactions Through Edward Jones

The following information has been provided by Edward Jones:

Effective on or after January 15, 2021, the following information supersedes prior information with respect to transactions and positions held in Columbia Fund shares through an Edward Jones system. Clients of Edward Jones (also referred to as "shareholders") purchasing Columbia Fund shares on the Edward Jones commission and fee-based platforms are eligible only for the following sales charge discounts (also referred to as "breakpoints") and waivers, which can differ from discounts and waivers described elsewhere in this prospectus or the Fund’s SAI or through another broker-dealer. In all instances, it is the shareholder's responsibility to inform Edward Jones at the time of purchase of any relationship, holdings of Columbia Funds and Future Scholars Program, or other facts qualifying the purchaser for discounts or waivers. Edward Jones can ask for documentation of such circumstance. Shareholders should contact Edward Jones if they have questions regarding their eligibility for these discounts and waivers.

Breakpoints

■ Breakpoint pricing, otherwise known as volume pricing, at dollar thresholds as described in this prospectus.

Rights of Accumulation (ROA)

■ The applicable sales charge on a purchase of Class A shares is determined by taking into account all share classes (except certain money market funds and any assets held in group retirement plans) of Columbia Funds and Future Scholars Program held by the shareholder or in an account grouped by Edward Jones with other accounts for the purpose of providing certain pricing considerations ("pricing groups"). If grouping assets as a shareholder, this includes all share classes held on the Edward Jones platform and/or held on another platform. The inclusion of eligible Columbia Fund assets in the ROA calculation is dependent on the shareholder notifying Edward Jones of such assets at the time of calculation. Money market funds are included only if such shares were sold with a sales charge at the time of purchase or acquired in exchange for shares purchased with a sales charge.

■ The employer maintaining a SEP IRA plan and/or SIMPLE IRA plan may elect to establish or change ROA for the IRA accounts associated with the plan to a plan-level grouping as opposed to including all share classes at a shareholder or pricing group level.

■ ROA is determined by calculating the higher of cost minus redemptions or market value (current shares x NAV).

Letter of Intent (LOI)

■ Through a LOI, shareholders can receive the sales charge and breakpoint discounts for purchases shareholders intend to make over a 13-month period from the date Edward Jones receives the LOI. The LOI is determined by calculating the higher of cost or market value of qualifying holdings at LOI initiation in combination with the value that the shareholder intends to buy over a 13-month period to calculate the front-end sales charge and any breakpoint discounts. Each purchase the shareholder makes during that 13-month period will receive the sales charge and breakpoint discount that applies to the total amount. The inclusion of eligible Columbia Fund assets in the LOI calculation is dependent on the shareholder notifying Edward Jones of such assets at the time of calculation. Purchases made before the LOI is received by Edward Jones are not adjusted under the LOI and will not reduce the sales charge previously paid. Sales charges will be adjusted if LOI is not met.

■ If the employer maintaining a SEP IRA plan and/or SIMPLE IRA plan has elected to establish or change ROA for the IRA accounts associated with the plan to a plan-level grouping, LOIs will also be at the plan-level and may only be established by the employer.

A-3 Prospectus 2022

Columbia Acorn European Fund^SM

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

Sales Charge Waivers

Sales charges are waived for the following shareholders and in the following situations:

■ Associates of Edward Jones and its affiliates and their family members who are in the same pricing group (as determined by Edward Jones under its policies and procedures) as the associate. This waiver will continue for the remainder of the associate's life if the associate retires from Edward Jones in good-standing and remains in good standing pursuant to Edward Jones' policies and procedures.

■ Shares purchased in an Edward Jones fee-based program.

■ Shares purchased through reinvestment of capital gains distributions and dividend reinvestment.

■ Shares purchased from the proceeds of redeemed shares of Columbia Funds so long as the following conditions are met: 1) the proceeds are from the sale of shares within 60 days of the purchase, and 2) the sale and purchase are made in the same share class and the same account or the purchase is made in an individual retirement account with proceeds from liquidations in a non-retirement account.

■ Shares exchanged into Class A shares from another share class so long as the exchange is into the same fund and was initiated at the discretion of Edward Jones. Edward Jones is responsible for any remaining CDSC due to the fund company, if applicable. Any future purchases are subject to the applicable sales charge as disclosed in this prospectus.

■ Exchanges from Class C shares to Class A shares of the same fund, generally, in the 84th month following the anniversary of the purchase date or earlier at the discretion of Edward Jones.

Contingent Deferred Sales Charge (CDSC) Waivers

If the shareholder purchases shares that are subject to a CDSC and those shares are redeemed before the CDSC is expired, the shareholder is responsible to pay the CDSC except in the following conditions:

■ The death or disability of the shareholder.

■ Systematic withdrawals with up to 10% per year of the account value.

■ Return of excess contributions from an Individual Retirement Account (IRA).

■ Shares sold as part of a required minimum distribution for IRA and retirement accounts if the redemption is taken in or after the year the shareholder reaches qualified age based on applicable IRS regulations.

■ Shares sold to pay Edward Jones fees or costs in such cases where the transaction is initiated by Edward Jones.

■ Shares exchanged in an Edward Jones fee-based program.

■ Shares acquired through NAV reinstatement.

■ Shares redeemed at the discretion of Edward Jones for Minimum Balances, as described below.

Other Important Information Regarding Transactions Through Edward Jones

Minimum Purchase Amounts

■ Initial purchase minimum: $250

■ Subsequent purchase minimum: none

Minimum Balances

■ Edward Jones has the right to redeem at its discretion Fund holdings with a balance of $250 or less. The following are examples of accounts that are not included in this policy:

■ A fee-based account held on an Edward Jones platform.

■ A 529 account held on an Edward Jones platform.

■ An account with an active systematic investment plan or LOI.

Prospectus 2022 A-4

Columbia Acorn European Fund^SM

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

Exchanging Share Classes

■ At any time it deems necessary, Edward Jones has the authority to exchange at NAV a shareholder's holdings in the Fund to Class A shares.

 Janney Montgomery Scott LLC (Janney)

The following information has been provided by Janney:

Effective May 1, 2020, if you purchase Columbia Fund shares through a Janney brokerage account, you will be eligible for the following load waivers (front-end sales charge waivers and CDSC, or back-end sales charge, waivers) and discounts, which may differ from those disclosed elsewhere in this prospectus or the Fund’s SAI. A reduction and/or waiver that is specific to Janney does not apply to non-omnibus positions.

Front-End Sales Charge* Waivers on Class A Shares Available at Janney

■ Shares purchased through reinvestment of capital gains distributions and dividend reinvestment when purchasing shares of the same fund (but not any other Columbia Fund).

■ Shares purchased by employees and registered representatives of Janney or its affiliates and their family members as designated by Janney.

■ Shares purchased from the proceeds of redemptions from another Columbia Fund, provided (1) the repurchase occurs within ninety (90) days following the redemption, (2) the redemption and purchase occur in the same account, and (3) redeemed shares were subject to a front-end or deferred sales load (i.e., right of reinstatement).

■ Employer-sponsored retirement plans (e.g., 401(k) plans, 457 plans, employer-sponsored 403(b) plans, profit sharing and money purchase pension plans and defined benefit plans). For purposes of this provision, employer-sponsored retirement plans do not include SEP IRAs, Simple IRAs, SAR-SEPs or Keogh plans.

■ Shares acquired through a right of reinstatement.

■ Class C shares that are no longer subject to a CDSC and are converted to Class A shares of the same fund pursuant to Janney’s policies and procedures.

CDSC Waivers on Class A and C Shares Available at Janney

■ Shares sold upon the death or disability of the shareholder.

■ Shares sold as part of a systematic withdrawal plan as described in this prospectus.

■ Shares purchased in connection with a return of excess contributions from an IRA account.

■ Shares sold as part of a required minimum distribution for IRA and retirement accounts if the redemption is taken in or after the year the shareholder reaches qualified age based on applicable IRS regulations.

■ Shares sold to pay Janney fees but only if the transaction is initiated by Janney.

■ Shares acquired through a right of reinstatement.

■ Shares exchanged into the same share class of a different fund.

Front-End Sales Charge* Discounts Available at Janney: Breakpoints, Rights of Accumulation, and/or Letters of Intent

■ Breakpoints as described in this prospectus.

■ Rights of accumulation (“ROA”), which entitle shareholders to breakpoint discounts, will be automatically calculated based on the aggregated holding of Columbia Fund assets held by accounts within the purchaser’s household at Janney. Eligible Columbia Fund assets not held at Janney may be included in the ROA calculation only if the shareholder notifies his or her financial advisor about such assets.

■ Letters of intent which allow for breakpoint discounts based on anticipated purchases within the Columbia Funds, over a 13-month time period. Eligible Columbia Fund assets not held at Janney may be included in the calculation of letters of intent only if the shareholder notifies his or her financial advisor about such assets.

A-5 Prospectus 2022

Columbia Acorn European Fund^SM

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

* Also referred to as an “initial sales charge”.

 Merrill Lynch Pierce, Fenner & Smith Incorporated (Merrill Lynch)

The following information has been provided by Merrill Lynch:

Shareholders purchasing Columbia Fund shares through a Merrill Lynch platform or account will be eligible only for the following load waivers (front-end sales charge waivers and contingent deferred, or back-end, sales charge waivers) and discounts, which may differ from those disclosed elsewhere in this prospectus or the Fund’s SAI:

Front-End Load Discounts Available at Merrill Lynch:

Merrill Lynch makes available breakpoint discounts on shares of the Fund through:

■ Breakpoints as described in this prospectus.

■ Rights of Accumulation (ROA) which entitle shareholders to breakpoint discounts as described in this prospectus will be automatically calculated based on the aggregated holding of Columbia Fund assets held by accounts (including 529 program holdings, where applicable) within the purchaser’s household at Merrill Lynch. Eligible Columbia Fund assets not held at Merrill Lynch may be included in the ROA calculation only if the shareholder notifies his or her financial advisor about such assets.

■ Letters of Intent (LOI) which allow for breakpoint discounts based on anticipated purchases of Columbia Funds, through Merrill Lynch, over a 13-month period of time (if applicable).

Front-End Sales Load Waivers on Class A Shares Available at Merrill Lynch:

■ Employer-sponsored retirement, deferred compensation and employee benefit plans (including health savings accounts) and trusts used to fund those plans, provided that the shares are not held in a commission-based brokerage account and shares are held for the benefit of the plan.

■ Shares purchased by a 529 Plan (does not include 529 Plan units or 529-specific share classes or equivalents).

■ Shares purchased through a Merrill Lynch affiliated investment advisory program.

■ Shares exchanged due to the holdings moving from a Merrill Lynch affiliated investment advisory program to a Merrill Lynch brokerage (non-advisory) account pursuant to Merrill Lynch’s policies relating to sales load discounts and waivers.

■ Shares purchased by third party investment advisors on behalf of their advisory clients through Merrill Lynch’s platform.

■ Shares of funds purchased through the Merrill Edge Self-Directed platform (if applicable).

■ Shares purchased through reinvestment of capital gains distributions and dividend reinvestment when purchasing shares of the same fund (but not any other Columbia Fund).

■ Shares exchanged from Class C (i.e., level-load) shares of the same fund pursuant to Merrill Lynch’s policies relating to sales load discounts and waivers.

■ Employees and registered representatives of Merrill Lynch or its affiliates and their family members.

■ Directors or Trustees of the Fund, and employees of the Fund’s investment adviser or any of its affiliates, as described in this prospectus.

■ Eligible shares purchased from the proceeds of redemptions from another Columbia Fund, provided (1) the repurchase occurs within 90 days following the redemption, (2) the redemption and purchase occur in the same account, and (3) redeemed shares were subject to a front-end or deferred sales load (known as Rights of Reinstatement). Automated transactions (i.e. systematic purchases and withdrawals) and purchases made after shares are automatically sold to pay Merrill Lynch’s account maintenance fees are not eligible for reinstatement.

CDSC Waivers on Class A and C Shares Available at Merrill Lynch:

■ Death or disability of the shareholder.

Prospectus 2022 A-6

Columbia Acorn European Fund^SM

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

■ Shares sold as part of a systematic withdrawal plan as described in this prospectus.

■ Return of excess contributions from an IRA Account.

■ Shares sold as part of a required minimum distribution for IRA and retirement accounts pursuant to the Internal Revenue Code.

■ Shares sold to pay Merrill Lynch fees but only if the transaction is initiated by Merrill Lynch.

■ Shares acquired through a right of reinstatement.

■ Shares held in retirement brokerage accounts, that are exchanged for a lower cost share class due to transfer to certain fee based accounts or platforms (applicable to Class A and Class C shares only).

■ Shares received through an exchange due to the holdings moving from a Merrill Lynch affiliated investment advisory program to a Merrill Lynch brokerage (non-advisory) account pursuant to Merrill Lynch’s policies relating to sales load discounts and waivers.

 Morgan Stanley Smith Barney, LLC (Morgan Stanley Wealth Management)

The following information has been provided by Morgan Stanley Wealth Management:

Effective July 1, 2018, shareholders purchasing Columbia Fund shares through a Morgan Stanley Wealth Management transactional brokerage account will be eligible only for the following front-end sales charge waivers with respect to Class A shares, which may differ from and may be more limited than those disclosed elsewhere in this prospectus or the Fund’s SAI.

Front-End Sales Charge Waivers on Class A Shares Available at Morgan Stanley Wealth Management Effective July 1, 2018:

■ Employer-sponsored retirement plans (e.g., 401(k) plans, 457 plans, employer-sponsored 403(b) plans, profit sharing and money purchase pension plans and defined benefit plans).  For purposes of this provision, employer-sponsored retirement plans do not include SEP IRAs, Simple IRAs, SAR-SEPs or Keogh plans.

■ Morgan Stanley employee and employee-related accounts according to Morgan Stanley’s account linking rules.

■ Shares purchased through reinvestment of dividends and capital gains distributions when purchasing shares of the same fund.

■ Shares purchased through a Morgan Stanley self-directed brokerage account.

■ Class C (i.e., level-load) shares that are no longer subject to a CDSC and are exchanged for Class A shares of the same fund pursuant to Morgan Stanley Wealth Management’s share class exchange program.

■ Shares purchased from the proceeds of redemptions from another Columbia Fund, provided (i) the repurchase occurs within 90 days following the redemption, (ii) the redemption and purchase occur in the same account, and (iii) redeemed shares were subject to a front-end or deferred sales charge.

 Raymond James & Associates, Inc., Raymond James Financial Services, Inc. and each entity’s affiliates (Raymond James)

The following information has been provided by Raymond James:

Intermediary-Defined Sales Charge Waiver Policies:

The availability of certain initial or deferred sales charge waivers and discounts may depend on the particular financial intermediary or type of account through which you purchase or hold Columbia Fund shares.

Intermediaries may have different policies and procedures regarding the availability of front-end sales load waivers or contingent deferred (back-end) sales load (CDSC) waivers, which are discussed below. In all instances, it is the purchaser’s responsibility to notify the Fund or the purchaser’s financial intermediary at the time of purchase of any

A-7 Prospectus 2022

Columbia Acorn European Fund^SM

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

relationship or other facts qualifying the purchaser for sales charge waivers or discounts. For waivers and discounts not available through a particular intermediary, shareholders will have to purchase Columbia Fund shares directly from the Fund or through another intermediary to receive these waivers or discounts.

Raymond James:

Effective March 1, 2019, shareholders purchasing Columbia Fund shares through a Raymond James platform or account, or through an introducing broker-dealer or independent registered investment adviser for which Raymond James provides trade execution, clearance, and/or custody services, will be eligible only for the following load waivers (front-end sales charge waivers and contingent deferred, or back-end, sales charge waivers) and discounts, which may differ from those disclosed elsewhere in this prospectus or the Fund’s SAI.

Front-End Sales Load Waivers on Class A Shares Available at Raymond James:

■ Shares purchased in an investment advisory program.

■ Shares purchased within the Columbia Funds through a systematic reinvestment of capital gains and dividend distributions.

■ Employees and registered representatives of Raymond James or its affiliates and their family members as designated by Raymond James.

■ Shares purchased from the proceeds of redemptions within the Columbia Funds, provided (1) the repurchase occurs within 90 days following the redemption, (2) the redemption and purchase occur in the same account, and (3) redeemed shares were subject to a front-end or deferred sales load (known as Rights of Reinstatement).

■ A shareholder in the Fund’s Class C shares will have their shares converted at net asset value to Class A shares (or the appropriate share class) of the Fund if the shares are no longer subject to a CDSC and the conversion is in line with the policies and procedures of Raymond James.

CDSC Waivers on Class A and Class C Shares Available at Raymond James:

■ Death or disability of the shareholder.

■ Shares sold as part of a systematic withdrawal plan as described in this prospectus.

■ Return of excess contributions from an IRA Account.

■ Shares sold as part of a required minimum distribution for IRA and retirement accounts due to the shareholder reaching the qualified age based on applicable IRS regulations as described in this prospectus.

■ Shares sold to pay Raymond James fees but only if the transaction is initiated by Raymond James.

■ Shares acquired through a right of reinstatement.

Front-End Load Discounts Available at Raymond James: Breakpoints, Rights of Accumulation and/or Letters of Intent:

■ Breakpoints as described in this prospectus.

■ Rights of accumulation which entitle shareholders to breakpoint discounts will be automatically calculated based on the aggregated holding of Columbia Fund assets held by accounts within the purchaser’s household at Raymond James. Eligible Columbia Fund assets not held at Raymond James may be included in the calculation of rights of accumulation only if the shareholder notifies his or her financial advisor about such assets.

■ Letters of intent which allow for breakpoint discounts based on anticipated purchases within the Columbia Funds, over a 13-month time period. Eligible Columbia Fund assets not held at Raymond James may be included in the calculation of letters of intent only if the shareholder notifies his or her financial advisor about such assets.

 Stifel Financial Corp. (Stifel)

The following information has been provided by Stifel:

Prospectus 2022 A-8

Columbia Acorn European Fund^SM

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

Effective June 30, 2020, Class C shares of Columbia Funds that were purchased through a Stifel platform or account that maintains an omnibus position with the Fund that are no longer subject to a CDSC are exchanged to Class A shares of the same Columbia Fund pursuant to Stifel’s policies and procedures. This does not apply to non-omnibus positions.

 U.S. Bancorp Investments, Inc. (USBI)

The following information has been provided by USBI:

Effective September of 2021, shareholders purchasing Columbia Fund shares through a USBI platform or who own shares for which USBI is the broker-dealer, where the shares are held in an omnibus account, will only be eligible for the following front-end sales charge waivers and discounts, which may differ from those disclosed elsewhere in this prospectus or the Fund’s SAI.

All other sales charge waivers and reduction described elsewhere in this prospectus or the Fund’s SAI still apply.

USBI Conversion of Class C shares

Class C (i.e., level-load) shares that are no longer subject to a contingent deferred sales charge are systematically converted to the Class A shares of the same fund pursuant to USBI’s share class exchange policy.

 Additional Sales Charge Reductions and/or Waivers Available at Certain Financial Intermediaries

Shareholders purchasing Columbia Fund shares through a platform or account of RBC Capital Markets, LLC are eligible for the following sales charge waiver:

Class A Shares Front-End Sales Charge Waiver Available at RBC Capital Markets, LLC:

■ For employer-sponsored retirement plans held through a commissionable brokerage account, Class A shares are available at NAV (i.e., without a sales charge). For this purpose, employer-sponsored retirement plans include, but are not limited to, 401(k) plans, 457 plans, employer-sponsored 403(b) plans, profit sharing and money purchase pension plans and defined benefit plans. For purposes of this provision, employer-sponsored retirement plans do not include SEP IRAs, Simple IRAs, SAR-SEPs or Keogh plans.

A-9 Prospectus 2022

[This page intentionally left blank]

Columbia Acorn European Fund^SM

P.O. Box 219104
Kansas City, MO 64121-9104

Columbia Acorn Family of Funds

Additional Information About the Fund

Additional information about the Fund’s investments is available in the Fund’s annual and semiannual reports to shareholders. In the annual report, you will find a discussion of the market conditions and investment strategies that significantly affected the Fund’s performance during its last fiscal year. The SAI also provides additional information about the Fund and its policies. The SAI, which has been filed with the SEC, is legally part of this prospectus (incorporated by reference). To obtain these documents free of charge, to request other information about the Fund and to make shareholder inquiries, please contact the Fund as follows:

By Mail:  Columbia Management Investment Services Corp.
P.O. Box 219104
Kansas City, MO 64121-9104

By Telephone: 800.345.6611

Online: columbiathreadneedleus.com

Shareholder Communications with the Board

The Fund’s Board of Trustees has adopted procedures by which shareholders may communicate with the Board. Shareholders who wish to communicate with the Board should send their written communications to the Board by mail, c/o Columbia Wanger Asset Management, LLC, 71 S. Wacker Drive, Suite 2500, Chicago, IL 60606, Attention: Secretary. Shareholder communications must (i) be in writing, (ii) identify the Columbia Acorn Fund to which the communication relates and (iii) state the particular class of shares and number of shares held by the communicating shareholder.

Obtaining Additional Information from the SEC

Reports and other information about the Fund are also available in the EDGAR Database on the SEC’s website at http://www.sec.gov. You can receive copies of this information, for a duplication fee, by electronic request at the following e-mail address: publicinfo@sec.gov.

The investment company registration number of Columbia Acorn Trust, of which the Fund is a series, is 811-01829.

Columbia Threadneedle Investments is the global brand name of the Columbia and Threadneedle group of companies.
The Fund is distributed by Columbia Management Investment Distributors, Inc., 290 Congress Street, Boston, MA 02210.

© 2022 Columbia Management Investment Advisers, LLC. All rights reserved.

PRO109_12_M01_(05/22)

 

Prospectus

May 1, 2022

Columbia Acorn Family of Funds

Managed by Columbia Wanger Asset Management, LLC

Columbia 
  Acorn® Fund

Class	Ticker Symbol
A	LACAX
Advisor (Class Adv)	CEARX
C	LIACX

Class	Ticker Symbol
Institutional (Class Inst)	ACRNX
Institutional 2 (Class Inst2)	CRBRX
Institutional 3 (Class Inst3)	CRBYX

As with all mutual funds, the Securities and Exchange Commission (SEC) has not approved or disapproved these securities or passed upon the adequacy of this prospectus. Any representation to the contrary is a criminal offense.

Table of Contents

Summary of the Fund	3
Investment Objective	3
Fees and Expenses of the Fund	3
Principal Investment Strategies	4
Principal Risks	5
Performance Information	8
Fund Management	9
Purchase and Sale of Fund Shares	9
Tax Information	10
Payments to Broker-Dealers and Other Financial Intermediaries	10
More Information About the Fund	11
Investment Objective	11
Principal Investment Strategies	11
Principal Risks	11
Additional Investment Strategies and Policies	15
Board of Trustees	20
Primary Service Provider Contracts	21
Other Roles and Relationships of Ameriprise Financial and its Affiliates — Certain Conflicts of Interest	23
Certain Legal Matters	24
Choosing a Share Class	25
The Funds	25
Summary of Share Class Features	25
Sales Charges and Commissions	31
Reductions/Waivers of Sales Charges	34
Distribution and Service Fees	38
Financial Intermediary Compensation	39
Buying, Selling and Exchanging Shares	41
Share Price Determination	41
Transaction Rules and Policies	42
Opening an Account and Placing Orders	46
Buying Shares	48
Selling Shares	53
Exchanging Shares	55
Distributions and Taxes	58
Distributions to Shareholders	58
Taxes	59
Financial Highlights	61
Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges	A-1

2

Columbia Acorn® Fund

Summary of the Fund

Investment Objective

Columbia Acorn^® Fund (the Fund) seeks long-term capital appreciation.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below. You may qualify for sales charge discounts if you and members of your immediate family invest, or agree to invest in the future, at least $50,000 in certain classes of shares of eligible funds distributed by Columbia Management Investment Distributors, Inc. (the Distributor). More information is available about these and other sales charge discounts and waivers from your financial intermediary, and can be found in the Choosing a Share Class section beginning on page 25 of the Fund’s prospectus, in Appendix A to the prospectus beginning on page A-1 and in Appendix S to the Statement of Additional Information (SAI) under Sales Charge Waivers beginning on page S-1.

Shareholder Fees (fees paid directly from your investment)
	Class A	Class C	Classes Adv, Inst, Inst2 and Inst3
Maximum sales charge (load) imposed on purchases (as a % of offering price)	5.75%	None	None
Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)	1.00%(a)	1.00%(b)	None

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
	Class A	Class Adv	Class C	Class Inst	Class Inst2	Class Inst3
Management fees	0.67%	0.67%	0.67%	0.67%	0.67%	0.67%
Distribution and/or service (12b-1) fees	0.25%	0.00%	1.00%	0.00%	0.00%	0.00%
Other expenses	0.16%	0.16%	0.16%	0.16%	0.14%	0.09%
Total annual Fund operating expenses(c)	1.08%	0.83%	1.83%	0.83%	0.81%	0.76%

(a)	This charge is imposed on certain investments of between $1 million and $50 million redeemed within 18 months after purchase, as follows: 1.00% if redeemed within 12 months after purchase, and 0.50% if redeemed more than 12, but less than 18, months after purchase, with certain limited exceptions.
(b)	This charge applies to redemptions within 12 months after purchase, with certain limited exceptions.

(c) “Total annual Fund operating expenses” include acquired fund fees and expenses (expenses the Fund incurs indirectly through its investments in other investment companies) and may be higher than the ratio of expenses to average net assets shown in the Financial Highlights section of this prospectus because the ratio of expenses to average net assets does not include acquired fund fees and expenses.

Prospectus 2022 3

Columbia Acorn® Fund

Summary of the Fund (continued)

 Example

The following example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example illustrates the hypothetical expenses that you would incur over the time periods indicated, and assumes that:

■ you invest $10,000 in the applicable class of Fund shares for the periods indicated,

■ your investment has a 5% return each year, and

■ the Fund’s total annual operating expenses remain the same as shown in the Annual Fund Operating Expenses table above.

Although your actual costs may be higher or lower, based on the assumptions listed above, your costs would be:

	1 year	3 years	5 years	10 years
Class A (whether or not shares are redeemed)	$679	$899	$1,136	$1,816
Class Adv (whether or not shares are redeemed)	$85	$265	$460	$1,025
Class C (assuming redemption of all shares at the end of the period)	$286	$576	$990	$1,951
Class C (assuming no redemption of shares)	$186	$576	$990	$1,951
Class Inst (whether or not shares are redeemed)	$85	$265	$460	$1,025
Class Inst2 (whether or not shares are redeemed)	$83	$259	$450	$1,002
Class Inst3 (whether or not shares are redeemed)	$78	$243	$422	$942

Portfolio Turnover

The Fund may pay transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 75% of the average value of its portfolio.

Principal Investment Strategies

Under normal circumstances, the Fund invests a majority of its net assets in the common stock of small- and mid-sized companies with market capitalizations generally in the range of market capitalizations in the Russell 2500 Growth Index, the Fund's benchmark, (the Index) at the time of purchase (between $21.5 million and $30 billion as of March 31, 2022). The market capitalization range and composition of companies in the Index are subject to change. As such, the size of the companies in which the Fund invests may change. The Fund determines a company’s market capitalization at the time of investment. As long as a majority of its net assets are invested in companies within the Index, the Fund may continue to hold and make new investments in a security even if the company’s market capitalization grows beyond the market capitalization of the largest company within the Index or falls below the market capitalization of the smallest company within the Index.

Columbia Wanger Asset Management, LLC, the Fund's investment adviser (the Investment Manager), believes that stocks of small- and mid-sized companies, which generally are not as well known by financial analysts as larger companies, may offer higher return potential than stocks of larger companies. The Fund invests the majority of its assets in U.S. companies, but also may invest up to 33% of its total assets in foreign companies in developed markets (for example, Japan, Canada and the United Kingdom) and in emerging markets (for example, China, India and Brazil). The Investment Manager from time to time emphasizes one or more sectors in selecting the Fund’s investments, including the consumer discretionary, health care, and information technology sectors. 

The Investment Manager typically seeks companies with: 

■ A strong business franchise that offers growth potential. 

■ Products and services in which the company has a competitive advantage. 

4 Prospectus 2022

Columbia Acorn® Fund

Summary of the Fund (continued)

■ A stock price the Investment Manager believes is reasonable relative to the assets and earning power of the company. 

The Investment Manager may sell a portfolio holding if the security reaches the Investment Manager's price target, if the company has a deterioration of fundamentals, such as failing to meet key operating benchmarks, or if the Investment Manager believes other securities are more attractive. The Investment Manager also may sell a portfolio holding to fund redemptions. 

Principal Risks

An investment in the Fund involves risks, including those described below, among others. There is no assurance that the Fund will achieve its investment objective and you may lose money. The value of the Fund’s holdings may decline, and the Fund’s net asset value (NAV) and share price may go down. An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Active Management Risk. The Investment Manager’s active management of the Fund could cause the Fund to underperform its benchmark index and/or other funds with similar investment objectives and/or strategies.

Small- and Mid-Cap Company Securities Risk. Investments in small- and mid-cap companies often involve greater risks than investments in larger, more established companies because small- and mid-cap companies tend to have less predictable earnings and may lack the management experience, financial resources, product diversification and competitive strengths of larger companies. Securities of small- and mid-cap companies may be less liquid and more volatile than the securities of larger companies.

Market Risk. The Fund may incur losses due to declines in the value of one or more securities in which it invests. These declines may be due to factors affecting a particular issuer, or the result of, among other things, political, regulatory, market, economic or social developments affecting the relevant market(s) more generally. In addition, turbulence in financial markets and reduced liquidity in equity, credit and/or fixed income markets may negatively affect many issuers, which could adversely affect the Fund’s ability to price or value hard-to-value assets in thinly traded and closed markets and could cause significant redemptions and operational challenges. Global economies and financial markets are increasingly interconnected, and conditions and events in one country, region or financial market may adversely impact issuers in a different country, region or financial market. These risks may be magnified if certain events or developments adversely interrupt the global supply chain; in these and other circumstances, such risks might affect companies worldwide. As a result, local, regional or global events such as terrorism, war, other conflicts, natural disasters, disease/virus outbreaks and epidemics or other public health issues, recessions, depressions or other events – or the potential for such events – could have a significant negative impact on global economic and market conditions. 

The large-scale invasion of Ukraine by Russia in February 2022 has resulted in sanctions and market disruptions including declines in regional and global stock and commodity markets and significant devaluations of Russian currency. The extent and duration of the military action are impossible to predict but could be significant. Market disruption caused by the Russian military action, and any counter measures or responses thereto (including international sanctions, a downgrade in the country’s credit rating, purchasing and financing restrictions, boycotts, tariffs, changes in consumer or purchaser preferences, cyberattacks and espionage) could have severe adverse impacts on regional and/or global securities and commodities markets, including markets for oil and natural gas. These impacts may include reduced market liquidity, distress in credit markets, further disruption of global supply chains, increased risk of inflation, and limited access to investments in certain international markets and/or issuers. These developments and other related events could negatively impact Fund performance. 

The pandemic caused by coronavirus disease 2019 and its variants (COVID-19) has resulted in, and may continue to result in, significant global economic and societal disruption and market volatility due to disruptions in market access, resource availability, facilities operations, imposition of tariffs, export controls and supply chain disruption, among others. Such disruptions may be caused, or exacerbated by, quarantines and travel restrictions, workforce displacement and loss in human and other resources. The uncertainty surrounding the magnitude, duration, reach, costs and effects of the global pandemic, as well as actions that have been or could be taken by governmental authorities or other third parties, present unknowns that are yet to unfold. The impacts, as well as the uncertainty 

Prospectus 2022 5

Columbia Acorn® Fund

Summary of the Fund (continued)

over impacts to come, of COVID-19 – and any other infectious illness outbreaks, epidemics and pandemics that may arise in the future – could negatively affect global economies and markets in ways that cannot necessarily be foreseen. In addition, the impact of infectious illness outbreaks and epidemics in less developed countries may be greater due to generally less established healthcare systems, governments and financial markets. Public health crises caused by the COVID-19 outbreak may exacerbate other pre-existing political, social and economic risks in certain countries or globally. The disruptions caused by COVID-19 could prevent the Fund from executing advantageous investment decisions in a timely manner and negatively impact the Fund’s ability to achieve its investment objective. Any such events could have a significant adverse impact on the value and risk profile of the Fund. 

Issuer Risk. An issuer in which the Fund invests may perform poorly, and the value of its securities may therefore decline, which may negatively affect the Fund’s performance. Underperformance of an issuer may be caused by poor management decisions, competitive pressures, breakthroughs in technology, reliance on suppliers, labor problems or shortages, corporate restructurings, fraudulent disclosures, natural disasters, military confrontations and actions, war, terrorism, disease/virus outbreaks and epidemics or other events, conditions and factors. 

Growth Securities Risk. Growth securities typically trade at a higher multiple of earnings than other types of equity securities. Accordingly, the market values of growth securities may never reach their expected market value and may decline in price. In addition, growth securities, at times, may not perform as well as value securities or the stock market in general, and may be out of favor with investors for varying periods of time. 

Liquidity and Trading Volume Risk. Because the Fund may invest a percentage of its assets in foreign securities, including in emerging markets, it may be subject to the liquidity and trading volume risks associated with international investing, including in emerging markets. Due to market conditions, including uncertainty regarding the price of a security, it may be difficult for the Fund to buy or sell foreign portfolio securities at a desirable time or price, which could result in investment losses and may affect the value of your investment in the Fund. This risk of portfolio illiquidity is heightened with respect to small- and mid-cap securities, generally, and foreign small- and mid-cap securities in particular. The Fund may have to lower the selling price, liquidate other investments, or forego another, more appealing investment opportunity as a result of illiquidity in the markets. The Fund may also be limited in its ability to execute favorable trades in foreign portfolio securities in response to changes in share prices and fundamentals, and may be forced to dispose of securities under disadvantageous circumstances and at a loss. As the Fund grows in size or, conversely, if it faces significant redemption pressure, these considerations take on increasing significance and may adversely impact performance. 

Sector Risk. At times, the Fund may have a significant portion of its assets invested in securities of companies conducting business within one or more economic sectors, including the consumer discretionary, health care, and information technology sectors. Companies in the same sector may be similarly affected by economic, regulatory, political or market events or conditions, which may make the Fund more vulnerable to unfavorable developments in that sector than funds that invest more broadly. Generally, the more broadly the Fund invests, the more it spreads risk and potentially reduces the risks of loss and volatility. 

■ Consumer Discretionary Sector. The Fund is more susceptible to the particular risks that may affect companies in the consumer discretionary sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the consumer discretionary sector are subject to certain risks, including fluctuations in the performance of the overall domestic and international economy, interest rate changes, increased competition and consumer confidence. Performance of such companies may be affected by factors including reduced disposable household income, reduced consumer spending, and changing demographics and consumer tastes. 

■ Health Care Sector. The Fund is more susceptible to the particular risks that may affect companies in the health care sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the health care sector are subject to certain risks, including restrictions on government reimbursement for medical expenses, government approval of medical products and services, competitive pricing pressures, and the rising cost of medical products and services (especially for companies dependent upon a relatively limited number of products or 

6 Prospectus 2022

Columbia Acorn® Fund

Summary of the Fund (continued)

services), among others. Performance of such companies may be affected by factors including, government regulation, obtaining and protecting patents (or the failure to do so), product liability and other similar litigation as well as product obsolescence. 

■ Information Technology Sector. The Fund is more susceptible to the particular risks that may affect companies in the information technology sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the information technology sector are subject to certain risks, including the risk that new services, equipment or technologies will not be accepted by consumers and businesses or will become rapidly obsolete. Performance of such companies may be affected by factors including obtaining and protecting patents (or the failure to do so) and significant competitive pressures, including aggressive pricing of their products or services, new market entrants, competition for market share and short product cycles due to an accelerated rate of technological developments. Such competitive pressures may lead to limited earnings and/or falling profit margins. As a result, the value of their securities may fall or fail to rise. In addition, many information technology sector companies have limited operating histories and prices of these companies’ securities historically have been more volatile than other securities, especially over the short term. Some companies in the information technology sector are facing increased government and regulatory scrutiny and may be subject to adverse government or regulatory action, which could negatively impact the value of their securities. 

Foreign Securities Risk. Investments in or exposure to securities of foreign companies may involve heightened risks relative to investments in or exposure to securities of U.S. companies. Investing in securities of foreign companies subjects the Fund to the risks associated with an issuer’s (and any of its related companies’) country of organization and places of business operations, including risks related to political, regulatory, economic, social, diplomatic and other conditions or events (including, for example, military confrontations and actions, war, other conflicts, terrorism and disease/virus outbreaks and epidemics) occurring in the country or region, as well as risks associated with less developed custody and settlement practices. Foreign securities may be more volatile and less liquid than securities of U.S. companies, and are subject to the risks associated with potential imposition of economic and other sanctions against a particular foreign country, its nationals or industries or businesses within the country. In addition, foreign governments may impose withholding or other taxes on the Fund’s income, capital gains or proceeds from the disposition of foreign securities, which could reduce the Fund’s return on such securities. 

Operational and Settlement Risks of Foreign Securities. The Fund’s foreign securities are generally held outside the United States in the primary market for the securities in the custody of foreign sub-custodians. Some countries have limited governmental oversight and regulation, which increases the risk of corruption and fraud and the possibility of losses to the Fund. In particular, under certain circumstances, foreign securities may settle on a delayed delivery basis, meaning that the Fund may be required to make payment for securities before the Fund has actually received delivery of the securities or deliver securities prior to the receipt of payment. As a result, there is a risk that the security will not be delivered to the Fund or that payment will not be received. Losses can also result from lost, stolen or counterfeit securities; defaults by brokers and banks; failures or defects of the settlement system; or poor and improper record keeping by registrars and issuers. 

Share Blocking. In certain non-U.S. markets, an issuer’s securities are blocked from trading for a specified number of days before and, in certain instances, after a shareholder meeting. The blocking period can last up to several weeks. Share blocking may prevent the Fund from buying or selling securities during this period. As a consequence of these restrictions, the Investment Manager, on behalf of the Fund, may abstain from voting proxies in markets that require share blocking. 

Emerging Market Securities Risk. Securities issued by foreign governments or companies in emerging market countries are more likely to have greater exposure to the risks of investing in foreign securities that are described in Foreign Securities Risk. In addition, emerging market countries are more likely to experience instability resulting, for example, from rapid changes or developments in social, political, economic or other conditions. Their economies are usually less mature and their securities markets are typically less developed with more limited trading activity (i.e., lower trading volumes and less liquidity) than more developed countries. Emerging market securities tend to be more volatile, and may be more susceptible to market manipulation, than securities in more developed markets. Many emerging market countries are heavily dependent on international trade and have fewer trading partners, which makes them more sensitive to world commodity prices and economic downturns in other countries, and some have a 

Prospectus 2022 7

Columbia Acorn® Fund

Summary of the Fund (continued)

higher risk of currency devaluations. Due to the differences in the nature and quality of financial information of issuers of emerging market securities, including auditing and financial reporting standards, financial information and disclosures about such issuers may be unavailable or, if made available, may be considerably less reliable than publicly available information about other foreign securities. 

Performance Information

The following bar chart and table show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. The bar chart shows how the Fund’s Class Inst share performance has varied for each full calendar year shown. The table below the bar chart compares the Fund’s returns for the periods shown with the Russell 2500 Growth Index.

The performance of one or more share classes shown in the Average Annual Total Returns table below includes the Fund’s Class Inst share returns (adjusted to reflect the higher class-related operating expenses of such classes, where applicable) for periods prior to the indicated inception date of such share classes. Except for differences in fees and expenses, all share classes of the Fund would have substantially similar annual returns because all share classes of the Fund invest in the same portfolio of securities.

The after-tax returns shown in the Average Annual Total Returns table below are calculated using the highest historical individual U.S. federal marginal income tax rates in effect during the period indicated in the table and do not reflect the impact of state, local or foreign taxes. Your actual after-tax returns will depend on your personal tax situation and may differ from those shown in the table. In addition, the after-tax returns shown in the table do not apply to shares held in tax-advantaged accounts such as 401(k) plans or Individual Retirement Accounts (IRAs). The after-tax returns are shown only for Class Inst shares and will vary for other share classes.

The Fund’s past performance (before and after taxes) is no guarantee of how the Fund will perform in the future. Updated performance information can be obtained by calling toll-free 800.345.6611 or visiting columbiathreadneedleus.com.

Year by Year Total Return (%) as of December 31 Each Year*	Best and Worst Quarterly Returns During the Period Shown in the Bar Chart
	Best	2nd Quarter 2020	28.34%
	Worst	1st Quarter 2020	-21.29%

* Year to Date return as of March 31, 2022: -17.51%

8 Prospectus 2022

Columbia Acorn® Fund

Summary of the Fund (continued)

 Average Annual Total Returns After Applicable Sales Charges (for periods ended December 31, 2021)

	Share Class Inception Date	1 Year	5 Years	10 Years
Class Inst	06/10/1970
returns before taxes		8.99%	16.26%	13.64%
returns after taxes on distributions		3.11%	11.83%	8.86%
returns after taxes on distributions and sale of Fund shares		8.92%	12.14%	9.79%
Class A returns before taxes	10/16/2000	2.57%	14.64%	12.68%
Class Adv returns before taxes	11/08/2012	9.03%	16.27%	13.61%
Class C returns before taxes	10/16/2000	7.10%	15.11%	12.51%
Class Inst2 returns before taxes	11/08/2012	9.09%	16.30%	13.67%
Class Inst3 returns before taxes	11/08/2012	9.16%	16.37%	13.73%
Russell 2500 Growth Index (reflects no deductions for fees, expenses or taxes)		5.04%	17.65%	15.75%

Fund Management

Investment Manager: Columbia Wanger Asset Management, LLC

Portfolio Management	Title	Role with Fund	Service with the Fund Since
Daniel Cole, CFA	Senior Portfolio Manager of Columbia Management Investment Advisers, LLC and Vice President of the Investment Manager	Co-Portfolio Manager since 2021	2021
Erika K. Maschmeyer, CFA	Director of Research (U.S.), Portfolio Manager and Analyst at the Investment Manager	Co-Portfolio Manager since 2019	2016
John L. Emerson, CFA	Portfolio Manager and Analyst at the Investment Manager	Co-Portfolio Manager since 2021	2003

Purchase and Sale of Fund Shares

You may purchase or redeem shares of the Fund on any business day by contacting the Fund in the ways described below:

Online	Regular Mail	Express Mail	By Telephone
columbiathreadneedleus.com/investor/	Columbia Management Investment Services Corp. P.O. Box 219104 Kansas City, MO 64121-9104	Columbia Management Investment Services Corp. c/o DST Asset Manager Solutions, Inc. 430 W 7th Street, Suite 219104 Kansas City, MO 64105-1407	800.422.3737

You may purchase shares and receive redemption proceeds by electronic funds transfer, by check or by wire. If you maintain your account with a broker-dealer or other financial intermediary, you must contact that financial intermediary to buy, sell or exchange shares of the Fund through your account with the intermediary.

The minimum initial investment amounts for the share classes offered by the Fund are shown below:

Prospectus 2022 9

Columbia Acorn® Fund

Summary of the Fund (continued)

Minimum Initial Investment

Class	Category of eligible account	For accounts other than Systematic Investment Plan accounts (as described in the Fund’s Prospectus)	For Systematic Investment Plan accounts
Classes A & C	All accounts other than IRAs	$2,000	$100
	IRAs	$1,000	$100
Classes Adv & Inst	All eligible accounts	$0, $1,000 or $2,000 depending upon the category of eligible investor	$100
Class Inst2	All eligible accounts	None	N/A
Class Inst3	All eligible accounts	$0, $1,000, $2,000 or $1 million depending upon the category of eligible investor	$100 (for certain eligible investors)

More information about these minimums can be found in the Buying, Selling and Exchanging Shares - Buying Shares section of the prospectus. There is no minimum additional investment for any share class.

Tax Information

The Fund normally distributes net investment income and net realized capital gains, if any, to shareholders. These distributions are generally taxable to you as ordinary income, qualified dividend income or capital gains, unless you are investing through a tax-advantaged account, such as a 401(k) plan or an IRA. If you are investing through a tax-advantaged account, you may be taxed upon withdrawals from that account.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase the Fund through a broker-dealer or other financial intermediary (such as a bank), the Fund and its related companies – including the Investment Manager, the Distributor and Columbia Management Investment Services Corp. (the Transfer Agent) – may pay the intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your financial advisor to recommend the Fund over another investment. These potential conflicts of interest may be heightened with respect to broker-dealers owned by Ameriprise Financial, Inc. (Ameriprise Financial) and/or its affiliates. Ask your financial advisor or visit your financial intermediary's website for more information.

10 Prospectus 2022

Columbia Acorn® Fund

More Information About the Fund

Investment Objective

Columbia Acorn^® Fund (the Fund) seeks long-term capital appreciation. The Fund’s investment objective is not a fundamental policy of the Fund and may be changed by the Fund’s Board of Trustees (the Board) without shareholder approval. There is no assurance the Fund’s objective will be achieved.

Principal Investment Strategies

Under normal circumstances, the Fund invests a majority of its net assets in the common stock of small- and mid-sized companies with market capitalizations generally in the range of market capitalizations in the Russell 2500 Growth Index, the Fund's benchmark, (the Index) at the time of purchase (between $21.5 million and $30 billion as of March 31, 2022). The market capitalization range and composition of companies in the Index are subject to change. As such, the size of the companies in which the Fund invests may change. The Fund determines a company’s market capitalization at the time of investment. As long as a majority of its net assets are invested in companies within the Index, the Fund may continue to hold and make new investments in a security even if the company’s market capitalization grows beyond the market capitalization of the largest company within the Index or falls below the market capitalization of the smallest company within the Index.

Columbia Wanger Asset Management, LLC, the Fund's investment adviser (the Investment Manager), believes that stocks of small- and mid-sized companies, which generally are not as well known by financial analysts as larger companies, may offer higher return potential than stocks of larger companies. The Fund invests the majority of its assets in U.S. companies, but also may invest up to 33% of its total assets in foreign companies in developed markets (for example, Japan, Canada and the United Kingdom) and in emerging markets (for example, China, India and Brazil). The Investment Manager from time to time emphasizes one or more sectors in selecting the Fund’s investments, including the consumer discretionary, health care, and information technology sectors.

The Investment Manager typically seeks companies with:

■ A strong business franchise that offers growth potential.

■ Products and services in which the company has a competitive advantage.

■ A stock price the Investment Manager believes is reasonable relative to the assets and earning power of the company.

The Investment Manager may sell a portfolio holding if the security reaches the Investment Manager's price target, if the company has a deterioration of fundamentals, such as failing to meet key operating benchmarks, or if the Investment Manager believes other securities are more attractive. The Investment Manager also may sell a portfolio holding to fund redemptions.

Principal Risks

An investment in the Fund involves risks, including those described below, among others. There is no assurance that the Fund will achieve its investment objective and you may lose money. The value of the Fund’s holdings may decline, and the Fund’s net asset value (NAV) and share price may go down. An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Active Management Risk. The Fund is actively managed and its performance therefore will reflect, in part, the ability of the Investment Manager to select investments and to make investment decisions that will achieve the Fund’s investment objective. The Investment Manager’s active management of the Fund could cause the Fund to underperform its benchmark index and/or other funds with similar investment objectives and/or strategies.

Small- and Mid-Cap Company Securities Risk. Securities of small- and mid-cap companies can, in certain circumstances, have a higher potential for gains than securities of larger, more established companies but may also have more risk. For example, small- and mid-cap companies may be more vulnerable to market downturns and adverse business or economic events than larger companies because they may have more limited financial resources and business operations. Small- and mid-cap companies are also more likely than larger companies to have more limited product lines and operating histories and to depend on smaller and generally less experienced management

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teams. Securities of small- and mid-cap companies may trade less frequently and in smaller volumes and may be less liquid and fluctuate more sharply in value than securities of larger companies. When the Fund takes significant positions in small- and mid-cap companies with limited trading volumes, the liquidation of those positions, particularly in a distressed market, could be prolonged and result in Fund investment losses that would affect the value of your investment in the Fund. In addition, some small- and mid-cap companies may not be widely followed by the investment community, which can lower the demand for their stocks.

Market Risk. The Fund may incur losses due to declines in the value of one or more securities in which it invests. These declines may be due to factors affecting a particular issuer, or the result of, among other things, political, regulatory, market, economic or social developments affecting the relevant market(s) more generally. In addition, turbulence in financial markets and reduced liquidity in equity, credit and/or fixed income markets may negatively affect many issuers, which could adversely affect the Fund’s ability to price or value hard-to-value assets in thinly traded and closed markets and could cause significant redemptions and operational challenges. Global economies and financial markets are increasingly interconnected, and conditions and events in one country, region or financial market may adversely impact issuers in a different country, region or financial market. These risks may be magnified if certain events or developments adversely interrupt the global supply chain; in these and other circumstances, such risks might affect companies worldwide. As a result, local, regional or global events such as terrorism, war, other conflicts, natural disasters, disease/virus outbreaks and epidemics or other public health issues, recessions, depressions or other events – or the potential for such events – could have a significant negative impact on global economic and market conditions.

The large-scale invasion of Ukraine by Russia in February 2022 has resulted in sanctions and market disruptions including declines in regional and global stock and commodity markets and significant devaluations of Russian currency. The extent and duration of the military action are impossible to predict but could be significant. Market disruption caused by the Russian military action, and any counter measures or responses thereto (including international sanctions, a downgrade in the country’s credit rating, purchasing and financing restrictions, boycotts, tariffs, changes in consumer or purchaser preferences, cyberattacks and espionage) could have severe adverse impacts on regional and/or global securities and commodities markets, including markets for oil and natural gas. These impacts may include reduced market liquidity, distress in credit markets, further disruption of global supply chains, increased risk of inflation, and limited access to investments in certain international markets and/or issuers. These developments and other related events could negatively impact Fund performance.

The pandemic caused by coronavirus disease 2019 and its variants (COVID-19) has resulted in, and may continue to result in, significant global economic and societal disruption and market volatility due to disruptions in market access, resource availability, facilities operations, imposition of tariffs, export controls and supply chain disruption, among others. Such disruptions may be caused, or exacerbated by, quarantines and travel restrictions, workforce displacement and loss in human and other resources. The uncertainty surrounding the magnitude, duration, reach, costs and effects of the global pandemic, as well as actions that have been or could be taken by governmental authorities or other third parties, present unknowns that are yet to unfold. The impacts, as well as the uncertainty over impacts to come, of COVID-19 – and any other infectious illness outbreaks, epidemics and pandemics that may arise in the future – could negatively affect global economies and markets in ways that cannot necessarily be foreseen. In addition, the impact of infectious illness outbreaks and epidemics in less developed countries may be greater due to generally less established healthcare systems, governments and financial markets. Public health crises caused by the COVID-19 outbreak may exacerbate other pre-existing political, social and economic risks in certain countries or globally. The disruptions caused by COVID-19 could prevent the Fund from executing advantageous investment decisions in a timely manner and negatively impact the Fund’s ability to achieve its investment objective. Any such events could have a significant adverse impact on the value and risk profile of the Fund.

Issuer Risk. An issuer in which the Fund invests may perform poorly, and the value of its securities may therefore decline, which may negatively affect the Fund’s performance. Underperformance of an issuer may be caused by poor management decisions, competitive pressures, breakthroughs in technology, reliance on suppliers, labor problems or shortages, corporate restructurings, fraudulent disclosures, natural disasters, military confrontations and actions, war, terrorism, disease/virus outbreaks and epidemics or other events, conditions and factors.

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Growth Securities Risk. Growth securities typically trade at a higher multiple of earnings than other types of equity securities. Accordingly, the market values of growth securities may never reach their expected market value and may decline in price. In addition, growth securities, at times, may not perform as well as value securities or the stock market in general, and may be out of favor with investors for varying periods of time.

Liquidity and Trading Volume Risk. Because the Fund may invest a percentage of its assets in foreign securities, including in emerging markets, it may be subject to the liquidity and trading volume risks associated with international investing, including in emerging markets. Due to market conditions, including uncertainty regarding the price of a security, it may be difficult for the Fund to buy or sell foreign portfolio securities at a desirable time or price, which could result in investment losses and may affect the value of your investment in the Fund. This risk of portfolio illiquidity is heightened with respect to small- and mid-cap securities, generally, and foreign small- and mid-cap securities in particular. The Fund may have to lower the selling price, liquidate other investments, or forego another, more appealing investment opportunity as a result of illiquidity in the markets. The Investment Manager will fair value in good faith any securities it deems to be illiquid under consistently applied procedures established by the Fund’s Board. Market conditions are always changing and vary by country and industry sector, and investing in international markets involves unique risks. Although it is difficult to accurately assess trends in trading volumes in foreign markets, a reduction in trading volumes poses challenges to the Fund. This is particularly so because the Fund focuses on small- and mid-cap companies that usually have lower trading volumes and often takes sizeable positions in portfolio companies. As a result of lower trading volumes, it may take longer to buy or sell these securities, which can exacerbate the Fund’s exposure to volatile markets. The Fund may also be limited in its ability to execute favorable trades in foreign portfolio securities in response to changes in share prices and fundamentals. If the Fund is forced to sell securities to meet redemption requests or other cash needs, or in the case of an event affecting liquidity in a particular market or markets, it may be forced to dispose of those securities under disadvantageous circumstances and at a loss. As the Fund grows in size or, conversely, if it faces significant redemption pressure, these considerations take on increasing significance and may adversely impact performance.

Sector Risk. At times, the Fund may have a significant portion of its assets invested in securities of companies conducting business within one or more economic sectors, including the consumer discretionary, health care, and information technology sectors. Companies in the same sector may be similarly affected by economic, regulatory, political or market events or conditions, which may make the Fund more vulnerable to unfavorable developments in that sector than funds that invest more broadly. Generally, the more broadly the Fund invests, the more it spreads risk and potentially reduces the risks of loss and volatility.

■ Consumer Discretionary Sector. The Fund is more susceptible to the particular risks that may affect companies in the consumer discretionary sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the consumer discretionary sector are subject to certain risks, including fluctuations in the performance of the overall domestic and international economy, interest rate changes, increased competition and consumer confidence. Performance of such companies may be affected by factors including reduced disposable household income, reduced consumer spending, and changing demographics and consumer tastes.

■ Health Care Sector. The Fund is more susceptible to the particular risks that may affect companies in the health care sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the health care sector are subject to certain risks, including restrictions on government reimbursement for medical expenses, government approval of medical products and services, competitive pricing pressures, and the rising cost of medical products and services (especially for companies dependent upon a relatively limited number of products or services), among others. Performance of such companies may be affected by factors including, government regulation, obtaining and protecting patents (or the failure to do so), product liability and other similar litigation as well as product obsolescence.

■ Information Technology Sector. The Fund is more susceptible to the particular risks that may affect companies in the information technology sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the information technology sector are subject to certain risks, including the risk that new services, equipment or technologies will not be accepted by consumers and businesses or will become rapidly obsolete. Performance of such companies may be affected by factors including obtaining and protecting patents (or the failure to do so) and significant competitive pressures, including aggressive pricing of their products or services,

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new market entrants, competition for market share and short product cycles due to an accelerated rate of technological developments. Such competitive pressures may lead to limited earnings and/or falling profit margins. As a result, the value of their securities may fall or fail to rise. In addition, many information technology sector companies have limited operating histories and prices of these companies’ securities historically have been more volatile than other securities, especially over the short term. Some companies in the information technology sector are facing increased government and regulatory scrutiny and may be subject to adverse government or regulatory action, which could negatively impact the value of their securities.

Foreign Securities Risk. Investments in or exposure to securities of foreign companies may involve heightened risks relative to investments in or exposure to securities of U.S. companies. For example, foreign markets can be extremely volatile. Foreign securities may also be less liquid, making them more difficult to trade, than securities of U.S. companies so that the Fund may, at times, be unable to sell foreign securities at desirable times or prices. Brokerage commissions, custodial costs and other fees are also generally higher for foreign securities. The Fund may have limited or no legal recourse in the event of default with respect to certain foreign securities, including those issued by foreign governments. In addition, foreign governments may impose withholding or other taxes on the Fund’s income, capital gains or proceeds from the disposition of foreign securities, which could reduce the Fund’s return on such securities. In some cases, such withholding or other taxes could potentially be confiscatory. Other risks include: possible delays in the settlement of transactions or in the payment of income; generally less publicly available information about foreign companies; the impact of economic, political, social, diplomatic or other conditions or events (including, for example, military confrontations and actions, war, other conflicts, terrorism and disease/virus outbreaks and epidemics), possible seizure, expropriation or nationalization of a company or its assets or the assets of a particular investor or category of investors; accounting, auditing and financial reporting standards that may be less comprehensive and stringent than those applicable to domestic companies; the imposition of economic and other sanctions against a particular foreign country, its nationals or industries or businesses within the country; and the generally less stringent standard of care to which local agents may be held in the local markets. In addition, it may be difficult to obtain reliable information about the securities and business operations of certain foreign issuers. Governments or trade groups may compel local agents to hold securities in designated depositories that are not subject to independent evaluation. The less developed a country’s securities market is, the greater the level of risks. Economic sanctions may be, and have been, imposed against certain countries, organizations, companies, entities and/or individuals. Economic sanctions and other similar governmental actions could, among other things, effectively restrict or eliminate the Fund’s ability to purchase or sell securities, and thus may make the Fund’s investments in such securities less liquid or more difficult to value. In addition, as a result of economic sanctions, the Fund may be forced to sell or otherwise dispose of investments at inopportune times or prices, which could result in losses to the Fund and increased transaction costs. These conditions may be in place for a substantial period of time and enacted with limited advance notice to the Fund. The risks posed by sanctions against a particular foreign country, its nationals or industries or businesses within the country may be heightened to the extent the Fund invests significantly in the affected country or region or in issuers from the affected country that depend on global markets. Additionally, investments in certain countries may subject the Fund to a number of tax rules, the application of which may be uncertain. Countries may amend or revise their existing tax laws, regulations and/or procedures in the future, possibly with retroactive effect. Changes in or uncertainties regarding the laws, regulations or procedures of a country could reduce the after-tax profits of the Fund, directly or indirectly, including by reducing the after-tax profits of companies located in such countries in which the Fund invests, or result in unexpected tax liabilities for the Fund.

Operational and Settlement Risks of Foreign Securities. The Fund’s foreign securities are generally held outside the United States in the primary market for the securities in the custody of certain eligible foreign banks and trust companies (“foreign sub-custodians”), as permitted under the Investment Company Act of 1940 (the 1940 Act). Settlement practices for foreign securities may differ from those in the United States. Some countries have limited governmental oversight and regulation of industry practices, stock exchanges, depositories, registrars, brokers and listed companies, which increases the risk of corruption and fraud and the possibility of losses to the Fund. In particular, under certain circumstances, foreign securities may settle on a delayed delivery basis, meaning that the Fund may be required to make payment for securities before the Fund has actually received delivery of the securities or deliver securities prior to the receipt of payment. Typically, in these cases, the Fund will receive evidence of ownership in accordance with the generally accepted settlement practices in the local market entitling the Fund to

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delivery or payment at a future date, but there is a risk that the security will not be delivered to the Fund or that payment will not be received, although the Fund and its foreign sub-custodians take reasonable precautions to mitigate this risk. Losses can also result from lost, stolen or counterfeit securities; defaults by brokers and banks; failures or defects of the settlement system; or poor and improper record keeping by registrars and issuers.

Share Blocking. Share blocking refers to a practice in certain foreign markets under which an issuer’s securities are blocked from trading at the custodian or sub-custodian level for a specified number of days before and, in certain instances, after a shareholder meeting where a vote of shareholders takes place. The blocking period can last up to several weeks. Share blocking may prevent the Fund from buying or selling securities during this period, because during the time shares are blocked, trades in such securities will not settle. It may be difficult or impossible to lift blocking restrictions, with the particular requirements varying widely by country. As a consequence of these restrictions, the Investment Manager, on behalf of the Fund, may abstain from voting proxies in markets that require share blocking.

Emerging Market Securities Risk. Securities issued by foreign governments or companies in emerging market countries are more likely to have greater exposure to the risks of investing in foreign securities that are described in Foreign Securities Risk. In addition, emerging market countries are more likely to experience instability resulting, for example, from rapid changes or developments in social, political, economic or other conditions. Their economies are usually less mature and their securities markets are typically less developed with more limited trading activity (i.e., lower trading volumes and less liquidity) than more developed countries. Emerging market securities tend to be more volatile, and may be more susceptible to market manipulation, than securities in more developed markets. Many emerging market countries are heavily dependent on international trade and have fewer trading partners, which makes them more sensitive to world commodity prices and economic downturns in other countries. Some emerging market countries have a higher risk of currency devaluations, and some of these countries may experience periods of high inflation or rapid changes in inflation rates and may have hostile relations with other countries. Due to the differences in the nature and quality of financial information of issuers of emerging market securities, including auditing and financial reporting standards, financial information and disclosures about such issuers may be unavailable or, if made available, may be considerably less reliable than publicly available information about other foreign securities.

Additional Investment Strategies and Policies

This section describes certain investment strategies and policies that the Fund may utilize in pursuit of its investment objective and some additional factors and risks involved with investing in the Fund. For information about risks associated with changing levels of Fund distributions, see the SAI.

Changing the Fund’s Investment Objective and Policies

The Fund’s investment objective and non-fundamental investment policies (including its principal and additional investment strategies) can be changed by the Board without shareholder approval, but may require notice to shareholders in certain instances. The Fund’s fundamental investment policies, as identified in the Fund’s Statement of Additional Information (SAI), may be changed only with Board and shareholder approval in accordance with the voting requirements of the 1940 Act. For additional information about changing the Fund’s fundamental and non-fundamental investment policies, see the SAI.

Investment Guidelines

As a general matter, and except as specifically described in the discussion of the Fund's principal investment strategies in this prospectus, whenever an investment policy or limitation states a percentage of the Fund's assets that may be invested in any security or other asset or sets forth a policy regarding an investment standard, compliance with that percentage limitation or standard will be determined based on the characteristics of a company at the time of initial purchase, and subsequent changes in a characteristic are not taken into account.

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Holding Other Kinds of Investments

The Fund may hold other investments that are not part of its principal investment strategies. These investments and their risks are described below and/or in the SAI. The Fund may choose not to invest in certain securities described in this prospectus and in the SAI, although it has the ability to do so. Information on the Fund’s holdings can be found in the Fund’s shareholder reports or by visiting columbiathreadneedleus.com.

Transactions in Derivatives

The Fund may enter into derivative transactions or otherwise have exposure to derivative transactions through underlying investments. The Fund expects to enter into such transactions primarily in the form of stock index futures in order to obtain exposure to the overall sector of the market represented by a particular stock index or to invest the Fund’s uninvested cash balances in a manner that the Investment Manager believes aligns more closely with the Fund’s investment strategy than simply holding short-term fixed income investments or cash equivalents (known as cash equitization). Derivatives are financial contracts whose values are, for example, based on (or “derived” from) traditional securities (such as a stock or bond), assets (such as a commodity like gold or a foreign currency), reference rates (such as the Secured Overnight Financing Rate (commonly known as SOFR) or the London Interbank Offered Rate (commonly known as LIBOR)) or market indices (such as the Standard & Poor's (S&P) 500^® Index). The use of derivatives is a highly specialized activity which involves investment techniques and risks different from those associated with ordinary portfolio securities transactions. Derivatives involve special risks and may result in losses or may limit the Fund's potential gain from favorable market movements. Derivative strategies typically expose the Fund to gains and losses in excess of the amount actually invested in the derivative. This characteristic of a derivative (known as "leverage") may exaggerate a loss, potentially causing the Fund to lose more money than it would have lost had it invested in the underlying security or other asset directly. The values of derivatives may move in unexpected ways, especially in unusual (including distressed) market conditions, and may result in increased volatility in the value of the derivative and/or the Fund’s shares, among other consequences. The use of derivatives may also increase the amount of taxes payable by shareholders holding shares in a taxable account. Other risks arise from the Fund's potential inability to terminate or to sell derivative positions. A liquid secondary market may not always exist for the Fund's derivative positions at times when the Fund might wish to terminate or to sell such positions. Over-the-counter instruments (investments not traded on an exchange) may be illiquid, and transactions in derivatives traded in the over-the-counter market are subject to the risk that the other party will not meet its obligations. The use of derivatives also involves the risks of mispricing or improper valuation and that changes in the value of the derivative may not correlate perfectly with the underlying security, asset, reference rate or index. The Fund also may not be able to find a suitable derivative transaction counterparty, and thus may be unable to engage in derivative transactions when it is deemed favorable to do so, or at all. U.S. federal legislation has been enacted that provides for new clearing, margin, reporting and registration requirements for participants in the derivatives market. These changes could restrict and/or impose significant costs or other burdens upon the Fund’s participation in derivatives transactions. The U.S. government and the European Union (and some other jurisdictions) have enacted regulations and similar requirements that prescribe clearing, margin, reporting and registration requirements for participants in the derivatives market. These requirements are evolving and their ultimate impact on the Fund remains unclear but such impact could include restricting and/or imposing significant costs or other burdens upon the Fund’s participation in derivatives transactions. Additionally, in October 2020, the SEC adopted new regulations governing the use of derivatives by registered investment companies. Once effective, Rule 18f-4 will, among other things, require funds that invest in derivative instruments beyond a specified limited amount to apply a value-at-risk based limit to their use of certain derivative instruments and establish a comprehensive derivatives risk management program. A fund that uses derivative instruments in a limited amount will not be subject to the full requirements of Rule 18f-4. Compliance with Rule 18f-4 will not be required until August 2022. Rule 18f-4 could have an adverse impact on the Fund’s performance and ability to implement its investment strategies as it has historically. For more information on the risks of derivative investments and strategies, see the SAI.

LIBOR Phase-Out Risk. Many derivatives and other financial instruments utilize or are permitted to utilize a floating interest rate based on LIBOR. On July 27, 2017, the United Kingdom's Financial Conduct Authority (FCA) announced its intention to phase out the use of LIBOR by the end of 2021. The FCA and the ICE Benchmark Administration have since announced that a majority of U.S. dollar LIBOR settings will cease publication after June 30, 2023. A subset of

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non-U.S. dollar LIBOR settings are continuing to be published on a “synthetic” basis and it is possible that a subset of U.S. dollar LIBOR settings will also be published after June 30, 2023 on a “synthetic” basis. Any such publications are, or would be considered, non-representative of the underlying market. Uncertainty related to the liquidity impact of changes in reference rates, and how to appropriately adjust these rates at the time of transition, poses risks for the Fund. It is difficult to predict the full impact of the transition away from LIBOR on the Fund until new reference rates and fallbacks for both legacy and new products, instruments and contracts are commercially accepted and market practices become more settled. The Investment Manager monitors the Fund's LIBOR exposure risks, including the extent to which any derivative and/or debt investments allow for the utilization of alternative rate(s), such as the Secured Overnight Financing Rate (SOFR), which the U.S. Federal Reserve is promoting as the alternative reference rate to LIBOR.

Affiliated Fund Investing

The Investment Manager and its affiliate, Columbia Management Investment Advisers, LLC (Columbia Management), each serves as investment adviser to mutual funds and ETFs using the Columbia brand (Columbia Funds), including mutual funds that are structured as “fund-of-funds”, and provides asset-allocation services to (i) shareholders by investing in shares of other Columbia Funds, which may include the Fund (collectively referred to in this section as Underlying Funds), and (ii) discretionary managed accounts (collectively referred to as affiliated products) that invest exclusively in Underlying Funds. These affiliated products, individually or collectively, may own a significant percentage of the outstanding shares of one or more Underlying Funds, and the Investment Manager and Columbia Management seek to balance potential conflicts of interest between the affiliated products and the Underlying Funds in which they invest. The affiliated products’ investment in the Underlying Funds may have the effect of creating economies of scale, possibly resulting in lower expense ratios for the Underlying Funds, because the affiliated products may own substantial portions of the shares of Underlying Funds. However, redemption of Underlying Fund shares by one or more affiliated products could cause the expense ratio of the Underlying Fund to increase, as its fixed costs would be spread over a smaller asset base. Because of large positions of certain affiliated products, the Underlying Funds may experience relatively large inflows and outflows of cash due to affiliated products’ purchases and sales of Underlying Fund shares. Although the Investment Manager or Columbia Management may seek to minimize the impact of these transactions where possible, for example, by structuring them over a reasonable period of time or through other measures, Underlying Funds may experience increased expenses as they buy and sell portfolio securities to manage the cash flow effect related to these transactions. Further, when the Investment Manager or Columbia Management structures transactions over a reasonable period of time in order to manage the potential impact of the buy and sell decisions for the affiliated products, those affiliated products, including funds-of-funds, may pay more or less (for purchase activity), or receive more or less (for redemption activity), for shares of the Underlying Funds than if the transactions were executed in one transaction. In addition, substantial redemptions by affiliated products within a short period of time could require the Underlying Fund to liquidate positions more rapidly than would otherwise be desirable, which may have the effect of reducing or eliminating potential gain or causing it to realize a loss. In order to meet such redemptions, the Underlying Fund may be forced to sell its liquid (or more liquid) positions, leaving the Underlying Fund holding, post-redemption, a relatively larger position in illiquid investments (i.e., any investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without the sale or disposition significantly changing the market value of the investment) or less liquid securities. Substantial redemptions may also adversely affect the ability of the Underlying Fund to implement its investment strategy. The Investment Manager or Columbia Management also has a conflict of interest in determining the allocation of affiliated products’ assets among the Underlying Funds, as it earns different fees from the various Underlying Funds.

Investing in Money Market Funds

The Fund may invest cash, including cash collateral received in connection with its securities lending program, in shares of money market funds, including funds advised by affiliates of the Investment Manager. These funds are not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency. The Fund and its shareholders indirectly bear a portion of the expenses of any money market fund or other fund in which the Fund may invest.

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Lending of Portfolio Securities

The Fund may lend portfolio securities to broker-dealers or other financial intermediaries on a fully collateralized basis in order to earn additional income. The Fund may lose money from securities lending if, for example, the borrower does not return a loaned security and the proceeds from sale of the collateral are not sufficient to replace the borrowed security. The Fund invests collateral in a government money market fund.

Investing Defensively

The Fund may from time to time take temporary defensive investment positions that are inconsistent with the Fund’s principal investment strategies in attempting to respond to adverse market, economic, political, social or other conditions. These investment positions may include, without limitation, investing some or all of its assets in money market instruments or shares of affiliated or unaffiliated money market funds or holding some or all of its assets in cash or cash equivalents. The Fund may take such defensive positions for as long a period as the Investment Manager deems necessary. During these times, the Investment Manager may make frequent portfolio changes, which could result in increased trading expenses and taxes, and decreased Fund performance.

Portfolio Holdings Disclosure

A description of the Fund’s policies and procedures with respect to the disclosure of Fund portfolio securities is available in the SAI. The Fund discloses its portfolio holdings on the Columbia Funds’ website, columbiathreadneedleus.com, as described below. Once posted, the portfolio holdings information will remain available on the website until at least the date on which such Fund files a Form N-CSR or publicly available Form N-PORT (forms filed with the SEC that include portfolio holdings information) for the period that includes the date as of which the information is current.

The Fund considers changes in its portfolio holdings to be confidential information. Consequently, Fund policy generally permits the disclosure of portfolio holdings information only after a certain amount of time has passed. The Fund’s complete portfolio holdings are disclosed approximately 30 to 40 days after each month-end. The top 15 holdings may be available sooner, approximately 15 calendar days after each month-end. Purchases and sales of portfolio securities can take place at any time, so the portfolio holdings information available on the website may not always be current.

Cybersecurity

The Fund, like all companies, may be susceptible to operational and information security risks, including the risk of cyber attacks or failures. As a result, the Fund or its service providers, or the issuers of securities in which the Fund invests, may experience disruptions in business operations that may potentially result in financial losses, the inability of the Fund or Fund shareholders to transact business, violations of applicable privacy and other laws, regulatory fines, penalties, reputational damage, reimbursement or other compensation costs, and/or additional compliance costs. The Fund and its shareholders could be negatively impacted as a result. See the discussion of Cybersecurity Breaches and Technology and Related Systems Failure Risk in the SAI for further information.

Use of Benchmarks

Benchmarks are indices that provide some comparative guidance in assessing the Fund’s performance. The Investment Manager selects the benchmarks it believes provide meaningful comparisons for each Fund. However, there may be different or additional indices that more closely reflect the market sectors in which the Fund invests. The Fund’s benchmarks may change from time to time. The benchmarks included in this prospectus are intended only as guideposts for your assessment of the Fund’s performance.

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 FUNDamentals

Portfolio Holdings Versus the Benchmarks

The Fund does not limit its investments to the securities within its benchmarks, and accordingly the Fund's holdings may diverge significantly from those of the benchmarks selected by the Investment Manager. In addition, the Fund may invest in securities outside the industry and geographic sectors represented in its benchmarks. The Fund's weightings in individual securities, and in industry and geographic sectors, may also vary considerably from those of its benchmarks.

eDelivery and Mailings to Households

In order to reduce shareholder expenses, the Fund may mail only one copy of the Fund’s prospectus and each annual and semiannual report to those addresses shared by two or more accounts. If you wish to receive separate copies of these documents, call 800.345.6611 or, if your shares are held through a financial intermediary, contact your intermediary directly. Additionally, you may elect to enroll in eDelivery to receive electronic versions of these documents, as well as quarterly statements and supplements, by logging into your account at columbiathreadneedleus.com/investor/.

Additional Information on Portfolio Turnover

A mutual fund that replaces, or turns over, more than 100% of its investments in a year may be considered to have a high portfolio turnover rate. A high portfolio turnover rate can generate larger distributions of short-term capital gains to shareholders, which for individuals are generally taxable at higher rates than long-term capital gains for U.S. federal income tax purposes. Also, a high portfolio turnover rate can mean higher brokerage commissions and other transaction costs, which could reduce a fund’s returns. In general, the greater the volume of buying and selling by a fund, the greater the impact that brokerage commissions and other transaction costs will have on its returns. The Fund may sell securities regardless of how long they’ve been held. See the Financial Highlights section of this prospectus for the Fund's portfolio turnover rates for the past five years.

Cash Flows

The timing and magnitude of cash inflows from investors buying Fund shares could prevent the Fund from always being fully invested. Conversely, the timing and magnitude of cash outflows to shareholders redeeming Fund shares could require the Fund to sell portfolio securities at less than opportune times or to hold ready reserves of uninvested cash in amounts larger than might otherwise be the case to meet shareholder redemptions. Either situation could adversely impact the Fund’s performance.

Understanding Annual Fund Operating Expenses

The Fund’s annual operating expenses, as presented in the Annual Fund Operating Expenses table in the Fees and Expenses of the Fund section of this prospectus, generally are based on expenses incurred during the Fund’s most recently completed fiscal year, may vary by share class and are expressed as a percentage (expense ratio) of the Fund’s average net assets during that fiscal year. The expense ratios reflect the Fund’s fee arrangements as of the date of this prospectus and, unless indicated otherwise, are based on expenses incurred during the Fund’s most recent fiscal year. The Fund’s assets will fluctuate, but unless indicated otherwise in the Annual Fund Operating Expenses table, no adjustments have been or will be made to the expense ratios to reflect any differences in the Fund’s average net assets between the most recently completed fiscal year and the date of this prospectus or a later date. In general, the Fund’s expense ratios will increase as its net assets decrease, such that the Fund’s actual expense ratios may be higher than the expense ratios presented in the Annual Fund Operating Expenses table if assets fall. Any commitment by the Investment Manager and/or its affiliates to waive fees and/or cap (reimburse) expenses is expected, in part, to limit the impact of any increase in the Fund’s expense ratios that would otherwise result because of a decrease in the Fund’s assets in the current fiscal year. The Fund’s annual operating expenses are comprised of (i) investment management fees, (ii) distribution and/or service fees, and (iii) other expenses.

Prospectus 2022 19

Columbia Acorn® Fund

More Information About the Fund (continued)

Management fees do not vary by class, but distribution and/or service fees and other expenses may vary by class. Please see Fee Waiver/Expense Reimbursement Arrangements below for information about commitments made by the Investment Manager and/or its affiliates during the performance period covered by this prospectus.

 FUNDamentals

Other Expenses

“Other expenses” consist of the fees the Fund pays to its administrator, custodian, transfer agent, auditors, lawyers and trustees, costs relating to compliance and miscellaneous expenses. Generally, these expenses are allocated on a pro rata basis across all share classes. These expenses include certain sub-transfer agency and shareholder servicing fees. Transfer agency fees and certain shareholder servicing fees, however, are class specific. They differ by share class because the shareholder services provided to each share class may be different. Accordingly, the differences in “other expenses” among share classes are primarily the result of the different transfer agency and shareholder servicing fees applicable to each share class. For more information on these fees, see Choosing a Share Class — Financial Intermediary Compensation.

Fee Waiver/Expense Reimbursement Arrangements

The Investment Manager has contractually agreed to waive fees and reimburse certain expenses of the Fund through April 30, 2023, so that ordinary operating expenses (excluding transaction costs and certain other investment-related expenses, interest and fees on borrowings, and expenses associated with the Fund’s investment in other investment companies, if any) do not exceed the annual rates of:

Columbia Acorn Fund
Class A	1.11%
Class Adv	0.86%
Class C	1.86%
Class Inst	0.86%
Class Inst2	0.84%
Class Inst3	0.79%

This arrangement may only be amended or terminated with approval from the Fund’s Board of Trustees and the Investment Manager.

Effect of Fee Waivers and/or Expense Reimbursements on Past Performance. The Fund’s returns shown in the Performance Information section of this prospectus reflect the effect of fee waivers and/or reimbursements of Fund expenses by the Investment Manager and/or its affiliates that were in place during the performance period shown in the Performance Information section of this prospectus. Without such fee waivers/expense reimbursements, the Fund’s returns might have been lower.

Board of Trustees

The Fund is governed by the Board. More than 75% of the Fund's Trustees are independent (Independent Trustees), meaning that they are not “interested persons” of the Fund, as defined in the 1940 Act. The Independent Trustees bring backgrounds in business and academia to their task of working with the Fund's officers to establish the Fund's policies and oversee its activities. Among the Trustees' responsibilities are: selecting the investment adviser for the Fund; approving the advisory agreement; reviewing other contracts; approving investment policies; monitoring Fund operations, performance, compliance and costs; and nominating or selecting new Trustees.

Each Trustee serves the Fund for an indefinite term until his or her retirement, resignation, death or removal in accordance with the organizational documents of Columbia Acorn Trust (the Trust). The Trust's Bylaws generally require that Trustees retire at the end of the calendar year in which they attain the age of 75 years. The last meeting

20 Prospectus 2022

Columbia Acorn® Fund

More Information About the Fund (continued)

to elect Trustees was held on February 27, 2015. Any Trustee may be removed at a shareholders' meeting by a vote representing two-thirds of the net asset value of all shares of the Columbia Acorn family of funds (Columbia Acorn Funds). The mailing address for the Trustees and officers is 71 S. Wacker Drive, Suite 2500, Chicago, Illinois 60606.

For more detailed information about the Board, please refer to the SAI.

Primary Service Provider Contracts

The Fund enters into contractual arrangements (Service Provider Contracts) with various parties, including, among others, the Investment Manager, the Distributor, the Transfer Agent and the Fund’s custodian. The Fund’s Service Provider Contracts are solely among the parties thereto. Shareholders are not parties to, or intended to be third-party beneficiaries of, any Service Provider Contracts. Further, this prospectus, the SAI and any Service Provider Contracts are not intended to give rise to any agreement, duty, special relationship or other obligation between the Fund and any investor, or give rise to any contractual, tort or other rights in any individual shareholder, group of shareholders or other person, including any right to assert a fiduciary or other duty, enforce the Service Provider Contracts against the parties or to seek any remedy thereunder, either directly or on behalf of the Fund. Nothing in the previous sentence should be read to suggest any waiver of any rights under federal or state securities laws.

The Investment Manager, which also serves as the Fund's administrator (the Administrator), Columbia Management, which serves as the Fund's sub-administrator pursuant to an agreement with the Investment Manager (the Sub-Administrator), the Distributor, and the Transfer Agent are all affiliates of Ameriprise Financial. They and their affiliates currently provide key services, including investment advisory, administration, distribution, shareholder servicing and transfer agency services, to the Fund and various other funds, including the Columbia Funds, and are paid for providing these services. These service relationships are described below.

The Investment Manager

Columbia Wanger Asset Management, LLC is located at 71 S. Wacker Drive, Suite 2500, Chicago, Illinois 60606. As of March 31, 2022, the Investment Manager had assets under management of approximately $9.2 billion. The Investment Manager is a registered investment adviser and wholly-owned subsidiary of Columbia Management, which is a wholly-owned subsidiary of Ameriprise Financial. In addition to serving as an investment adviser to mutual funds, the Investment Manager acts as an investment manager for other private funds and institutional accounts.

Subject to oversight by the Board, the Investment Manager manages the day-to-day operations of the Fund, determining what securities and other investments the Fund should buy or sell and executing portfolio transactions. The Investment Manager may use the research and other capabilities of its affiliates and third parties in managing the Fund’s investments.

The Fund pays the Investment Manager a fee for its investment advisory services. The fee is calculated as a percentage of the daily net assets of the Fund and is paid monthly. For the Fund’s most recent fiscal year, aggregate fees paid to the Investment Manager by the Fund amounted to 0.67% of average daily net assets of the Fund, before any applicable reimbursements.

A discussion regarding the basis for the Board’s approval of the renewal of the Fund’s investment management services agreement with the Investment Manager is available in the Fund’s annual report to shareholders for the fiscal year ended December 31, 2021.

The Investment Manager and its investment advisory affiliates, including Columbia Management (Affiliates), around the world may coordinate in providing services to their clients. From time to time, the Investment Manager may engage its Affiliates to provide a variety of services such as investment research, investment monitoring, trading, and discretionary investment management (including portfolio management and proxy voting) to certain accounts managed by the Investment Manager, including the Fund. These Affiliates will provide services to the Fund and other accounts of the Investment Manager either pursuant to delegation agreements, personnel-sharing agreements or similar inter-company or other arrangements or relationships and the Fund will pay no additional fees and expenses as a result of any such arrangements or relationships. These Affiliates, like the Investment Manager, are direct or indirect subsidiaries of Ameriprise Financial and are registered with the appropriate respective regulators and, where required, the SEC and the Commodity Futures Trading Commission in the United States.

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Columbia Acorn® Fund

More Information About the Fund (continued)

Pursuant to some of these arrangements or relationships, certain personnel of Columbia Management and other Affiliates may serve as “associated persons” or officers of the Investment Manager and, in this capacity, subject to the oversight and supervision of the Investment Manager and consistent with the investment objectives, policies and limitations set forth in this prospectus and the Fund's SAI, and with the Investment Manager’s and the Funds’ compliance policies and procedures, may provide such services to the Fund.

Portfolio Managers

Information about the portfolio managers primarily responsible for overseeing the Fund’s investments is shown below. The SAI provides additional information about the portfolio managers, including information relating to compensation, other accounts managed by the portfolio managers, and ownership by the portfolio managers of Fund shares.

Portfolio Management	Title	Role with Fund	Service with the Fund Since
Daniel Cole, CFA	Senior Portfolio Manager of Columbia Management and Vice President of the Investment Manager	Co-Portfolio Manager since 2021	2021
Erika K. Maschmeyer, CFA	Director of Research (U.S.), Portfolio Manager and Analyst at the Investment Manager	Co-Portfolio Manager since 2019	2016
John L. Emerson, CFA	Portfolio Manager and Analyst at the Investment Manager	Co-Portfolio Manager since 2021	2003

Mr. Cole joined Columbia Management, an affiliate of the Investment Manager, in 2014 and has served as a Vice President of the Investment Manager since April 2021 and as a Vice President of the Trust since March 2022. Mr. Cole began his investment career in 1993 and earned a B.S. from Guilford College and an M.B.A. in finance from Virginia Polytechnic Institute and State University.

Ms. Maschmeyer has been associated with the Investment Manager as an investment professional since 2016. Ms. Maschmeyer heads the Investment Manager's U.S. equity research efforts and has been a Vice President of the Trust since March 2020. Prior to joining the Investment Manager, Ms. Maschmeyer was a research analyst at an investment advisory firm where she was responsible for U.S. consumer discretionary/staples investments. Ms. Maschmeyer began her investment career in 2001 and earned a B.A. from Denison University and an M.B.A from the University of Chicago.

Mr. Emerson has been associated with the Investment Manager or its predecessors as an investment professional since 2003 and has been a Vice President of the Trust since March 2020. Prior to joining the Investment Manager, Mr. Emerson was an analyst at an equity research firm. Mr. Emerson began his investment career in 2002 and earned a B.S. from the University of Missouri and an M.B.A from the University of Chicago.

The Administrator

Columbia Wanger Asset Management, LLC is responsible for overseeing the administrative operations of the Fund, including the general supervision of the Fund’s operations, coordination of the Fund’s service providers, and the provision of office facilities and related clerical and administrative services. The Administrator retains the Sub-Administrator to perform many of these services (including fund accounting), and pays a fee for the services of the Sub-Administrator. The Fund pays the Administrator a fee for its services, plus certain out-of-pocket expenses. The fee is calculated as an annual percentage of the Trust’s aggregate average daily net assets and is paid monthly, as follows:

Annual Administration Fee, as a % of Aggregate Daily Net Assets of the Trust:
Up to $8 billion	0.050%
$8 billion to $16 billion	0.040%
$16 billion to $35 billion	0.030%
$35 billion to $45 billion	0.025%

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Columbia Acorn® Fund

More Information About the Fund (continued)

Annual Administration Fee, as a % of Aggregate Daily Net Assets of the Trust:
$45 billion and over	0.015%

The Distributor

Shares of the Fund are distributed by Columbia Management Investment Distributors, Inc., which is located at 290 Congress Street, Boston, MA 02210. The Distributor is a registered broker-dealer and an indirect, wholly-owned subsidiary of Ameriprise Financial. The Distributor and its affiliates may pay commissions, distribution and service fees and/or other compensation to entities, including Ameriprise Financial affiliates, for selling shares and providing services to investors.

The Transfer Agent

Columbia Management Investment Services Corp. is a registered transfer agent and wholly-owned subsidiary of Ameriprise Financial. The Transfer Agent is located at 290 Congress Street, Boston, MA 02210, and its responsibilities include processing purchases, redemptions and exchanges of Fund shares, calculating and paying distributions, maintaining shareholder records, preparing account statements and providing customer service. The Transfer Agent has engaged DST Asset Manager Solutions, Inc. to provide various shareholder or “sub-transfer agency” services. In addition, the Transfer Agent enters into agreements with various financial intermediaries through which you may hold Fund shares, pursuant to which the Transfer Agent pays these financial intermediaries for providing certain shareholder services. Depending on the type of account, the Fund pays the Transfer Agent a per account fee for each open account and compensates the Transfer Agent for certain out-of-pocket expenses, including certain payments to financial intermediaries through which shares are held. In addition, subject to certain limitations, the Fund compensates the Transfer Agent for payments made to financial intermediaries for the shareholder services that the intermediaries provide, in amounts that vary by share class and with the type of intermediary and the type of shareholder services provided. The Transfer Agent is contractually obligated to oversee such intermediaries for the purpose of reasonably assuring their compliance with applicable law and the terms of their agreements to provide the shareholder services. For more information about Shareholder Services fees, see Choosing a Share Class — Financial Intermediary Compensation.

Other Roles and Relationships of Ameriprise Financial and its Affiliates — Certain Conflicts of Interest

This section describes certain actual and potential conflicts of interest that arise from the financial services activities of Ameriprise Financial and its affiliates. Ameriprise Financial is a major financial services company, engaged in a broad range of financial activities beyond the fund-related activities of the Investment Manager, including: insurance, broker-dealer (sales and trading), asset management and financial services. As a consequence of these activities, Ameriprise Financial or its affiliates may have interests arising from their other business lines that conflict with the interests of the Fund. These activities may also, from time to time, place certain investment constraints on the management of the Fund that might not otherwise arise.

As described in More Information About the Fund - Primary Service Provider Contracts, the Investment Manager, Administrator, Sub-Administrator, Distributor and Transfer Agent are all affiliates of Ameriprise Financial. In addition to the services that they provide to the Fund, they also provide substantially similar services (for which they are compensated) to other clients and customers, including the Columbia Funds. Ameriprise Financial and its other affiliates may also provide services (for which they are compensated) to the Fund, other Columbia Funds or other clients and customers.

Examples of activities that could lead to conflicts of interest and/or impose limitations that could affect the Fund include the following:

■ the Investment Manager and other Ameriprise Financial affiliates may receive compensation and other benefits related to the management/administration of the Fund and the other Columbia Funds and the sale of their shares;

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Columbia Acorn® Fund

More Information About the Fund (continued)

■ there may be competition for limited investment opportunities that must be allocated among the Fund, the other Columbia Funds and other clients and customers of the Investment Manager (which can include affiliates of the Investment Manager) that may have the same or similar investment objectives as the Fund;

■ management of the Fund may diverge from other Columbia Funds or other clients and customers of the Investment Manager or Ameriprise Financial affiliates, for example, advice given to the Fund may differ from, or conflict with, advice given to other funds or accounts;

■ there may be regulatory or investment restrictions imposed on the investment activities of the Investment Manager arising from the activities or holdings of other Columbia Funds or other clients or customers of the Investment Manager or Ameriprise Financial and its affiliates, for example, caps on the aggregate amount of certain types of investments or in holdings of particular portfolio companies that may be made by affiliated entities, including the Fund;

■ Ameriprise Financial or its affiliates may have potentially conflicting relationships with companies and other entities in which the Fund invests; and

■ there may be regulatory and other restrictions relating to the sharing of information between Ameriprise Financial and its affiliates, including the Investment Manager, for example, if an affiliated entity were in possession of non-public information, the Investment Manager might be prohibited by law from using that information in connection with the management of the Fund.

The Investment Manager and Ameriprise Financial have adopted various policies and procedures that are intended to identify, monitor and address conflicts of interest. However, there is no absolute assurance that these policies, procedures and disclosures will be effective.

Additional information about Ameriprise Financial and the types of conflicts of interest and other matters referenced above is set forth in the Investment Advisory and Other Services – Other Roles and Relationships of Ameriprise Financial and Affiliates – Certain Conflicts of Interest section of the SAI. Investors in the Fund should carefully review these disclosures and consult with their financial advisor if they have any questions.

Certain Legal Matters

Ameriprise Financial and certain of its affiliates are involved in the normal course of business in legal proceedings which include regulatory inquiries, arbitration and litigation, including class actions concerning matters arising in connection with the conduct of its activities as a diversified financial services firm. Ameriprise Financial believes that the Fund is not currently the subject of, and that neither Ameriprise Financial nor any of its affiliates are the subject of, any pending legal, arbitration or regulatory proceedings that are likely to have a material adverse effect on the Fund or the ability of Ameriprise Financial or its affiliates to perform under their contracts with the Fund. Information regarding certain pending and settled legal proceedings may be found in the Fund’s shareholder reports and in the SAI. Additionally, Ameriprise Financial is required to make quarterly (10-Q), annual (10-K) and, as necessary, 8-K filings with the SEC on legal and regulatory matters that relate to Ameriprise Financial and its affiliates. Copies of these filings may be obtained by accessing the SEC website at sec.gov.

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Columbia Acorn® Fund

Choosing a Share Class

The Funds

The Columbia Acorn Funds and the other Columbia Funds generally share the same policies and procedures for investor services, as described below. Together, the Fund and the other Columbia Acorn Funds, along with the Columbia Funds, are referred to herein as the Funds.

Funds Contact Information

Additional information about the Funds, including sales charges and other class features and policies, can be obtained, free of charge, at columbiathreadneedleus.com,* by calling toll-free 800.345.6611, or by writing (regular mail) to Columbia Management Investment Services Corp., P.O. Box 219104, Kansas City, MO 64121-9104 or (express mail) Columbia Management Investment Services Corp., c/o DST Asset Manager Solutions, Inc., 430 W 7^th Street, Ste 219104, Kansas City, MO 64105-1407.

* The website references in this prospectus are inactive links and information contained in or otherwise accessible through the referenced websites does not form a part of this prospectus.

 FUNDamentals

Financial Intermediaries

The term “financial intermediary” refers to the selling and servicing agents that are authorized to sell and/or service shares of the Funds. Financial intermediaries include broker-dealers and financial advisors as well as firms that employ broker-dealers and financial advisors, including, for example, brokerage firms, banks, investment advisers, third party administrators and other firms in the financial services industry.

Omnibus Accounts

The term “omnibus account” refers to a financial intermediary’s account with the Fund (held directly through the Transfer Agent) that represents the combined holdings of, and transactions in, Fund shares of one or more clients of the financial intermediary (beneficial Fund shareholders). Omnibus accounts are held in the name of the financial intermediaries and not in the name of the beneficial Fund shareholders invested in the Fund through omnibus accounts.

Retirement Plans and Omnibus Retirement Plans

The term “retirement plan” refers to retirement plans created under Sections 401(a), 401(k), 457 and 403(b) of the Internal Revenue Code of 1986, as amended (the Code), and non-qualified deferred compensation plans governed by Section 409A of the Code and similar plans, but does not refer to individual retirement plans, such as traditional IRAs and Roth IRAs. The term “omnibus retirement plan” refers to a retirement plan that has a plan-level or omnibus account with the Transfer Agent.

Networked Accounts

Networking, offered by the Depository Trust & Clearing Corporation’s Wealth Management Services (WMS), is the industry standard IT system for mutual fund account reconciliation and dividend processing.

Summary of Share Class Features

Each share class has its own investment eligibility criteria, cost structure and other features. You may not be eligible to invest in every share class. Your financial intermediary may not make every share class available or may cease to make available one or more share classes of the Fund. The share class you select through your financial intermediary may have higher fees and/or sales charges than other classes of shares available through other financial intermediaries. An investor transacting in a class of Fund shares without any front-end sales charge, contingent deferred sales charge (CDSC), or other asset-based fee for sales or distribution, such as a Rule 12b-1 fee, may be required to pay a commission to the financial intermediary for effecting such transactions. Each investor’s personal situation is different and you may wish to discuss with your financial intermediary the share classes the Fund offers, which share classes are available to you and which share class(es) is/are appropriate for you. In all instances, it is your responsibility to notify your financial intermediary or (for Direct-at-Fund Accounts, as

Prospectus 2022 25

Columbia Acorn® Fund

Choosing a Share Class (continued)

defined below) the Fund at the time of purchase of any relationship or other facts that may qualify you for sales charge waivers or discounts. The Fund, the Distributor and the Transfer Agent do not provide investment advice or make recommendations regarding Fund share classes. Your financial intermediary may provide advice and recommendations to you, such as which share class(es) is/are appropriate for you.

When deciding which class of shares to buy, you should consider, among other things:

■ The amount you plan to invest.

■ How long you intend to remain invested in the Fund.

■ The fees (e.g., sales charge or “load”) and expenses for each share class.

■ Whether you may be eligible for a reduction or waiver of sales charges when you buy or sell shares.

 FUNDamentals

Front-End Sales Charge Calculation

The front-end sales charge is calculated as a percentage of the offering price.

■ The net asset value (NAV) per share is the price of a share calculated by the Fund every business day.

■ The offering price per share is the NAV per share plus any front-end sales charge (or load) that applies.

The dollar amount of any applicable front-end sales charge is the difference between the offering price of the shares you buy and the NAV of those shares. To determine the front-end sales charge you will pay when you buy Class A shares, the Fund will add the amount of your investment to the value of your account (and any other accounts eligible for aggregation of which you or your financial intermediary notifies the Fund) and base the sales charge on the aggregate amount. For information on account value aggregation, sales charge waivers and other important information, see Choosing a Share Class — Reductions/Waivers of Sales Charges.

 FUNDamentals

Contingent Deferred Sales Charge

A contingent deferred sales charge (CDSC) is a sales charge applied at the time you sell your shares, unlike a front-end sales charge that is applied at the time of purchase. A CDSC can vary based on the length of time that you have held your shares. A CDSC is applied to the NAV at the time of your purchase or sale, whichever is lower, and will not be applied to any shares you receive through Fund distribution reinvestments or any amount that represents appreciation in the value of your shares. For purposes of calculating a CDSC, the start of the holding period is generally the first day of the month in which your purchase was made.

When you place an order to sell shares of a class that has a CDSC, the Fund will first redeem any shares that are not subject to a CDSC, followed by those you have held the longest. This means that if a CDSC is imposed, you cannot designate the individual shares being redeemed for U.S. federal income tax purposes. You should consult your tax advisor about the tax consequences of investing in the Fund. In certain circumstances, the CDSC may not apply. See Choosing a Share Class — Reductions/Waivers of Sales Charges for details.

Share Class Features

The following summarizes the primary features of Class A, Class Adv, Class C, Class Inst, Class Inst2, Class Inst3, and Class R shares.

Not all Funds offer every class of shares. The Fund offers the class(es) of shares set forth on the cover of this prospectus and may offer other share classes through a separate prospectus. Although certain share classes are generally closed to new and/or existing investors, information relating to these share classes is included in the table below because certain qualifying purchase orders are permitted, as described below.

26 Prospectus 2022

Columbia Acorn® Fund

Choosing a Share Class (continued)

The sales charge reductions and waivers available to investors who purchase and hold their Fund shares through different financial intermediaries may vary. Appendix A describes financial intermediary-specific reductions and/or waiver policies. A shareholder transacting in Fund shares through a financial intermediary identified in Appendix A should carefully read the terms and conditions of Appendix A. A reduction and/or waiver that is specific to a particular financial intermediary is not available to Direct-at-Fund Accounts, as defined below, or through another financial intermediary. The information in Appendix A may be provided by, or compiled from or based on information provided by the financial intermediaries identified in Appendix A. To obtain additional information regarding any sales charge reduction and/or waiver described in Appendix A, and to ensure that you receive any such reductions or waivers that may be available to you, please consult your financial intermediary.

Share Class	Eligible Investors; Minimum Initial Investments; Conversion Features(a)	Front-End Sales Charges(b)	Contingent Deferred Sales Charges (CDSCs)(b)	Sales Charge Reductions/Waivers	Maximum Distribution and/or Service (12b-1) Fees(c)
Class A	Eligibility: Available to the general public for investment Minimum Initial Investment: $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts (as described below))	5.75% maximum, declining to 0.00% on investments of $1 million or more	CDSC on certain investments of between $1 million and $50 million redeemed within 18 months after purchase charged as follows: • 1.00% CDSC if redeemed within 12 months after purchase and • 0.50% CDSC if redeemed more than 12, but less than 18, months after purchase	Reductions: yes, see Choosing a Share Class — Reductions/Waivers of Sales Charges – Class A Shares Front-End Sales Charge Reductions Waivers: yes, on Fund distribution reinvestments. For additional waivers, see Choosing a Share Class — Reductions/Waivers of Sales Charges – Class A Shares Front-End Sales Charge Waivers, as well as Choosing a Share Class — CDSC Waivers – Class A and Class C Financial intermediary-specific waivers are also available, see Appendix A	Service Fee: 0.25%
Class Adv	Eligibility: Available only to (i) omnibus retirement plans, including self-directed brokerage accounts within omnibus retirement plans that clear through institutional no transaction fee (NTF) platforms; retirement plans; (ii) trust companies or similar institutions; (iii) broker-dealers, banks, trust companies and similar institutions that clear Fund share transactions for their client or customer investment advisory or similar accounts through designated financial intermediaries and their mutual fund trading platforms that have been granted specific written authorization from the Transfer Agent with respect to Class Adv eligibility apart from selling, servicing or similar agreements; (iv) 501(c)(3) charitable organizations; (v) 529 plans; (vi) health savings accounts; (vii) investors participating in a fee-based advisory program sponsored by a financial intermediary or other entity that is not compensated by the Fund for those services, other than payments for shareholder servicing or sub-accounting performed in place	None	None	N/A	None

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Columbia Acorn® Fund

Choosing a Share Class (continued)

Share Class	Eligible Investors; Minimum Initial Investments; Conversion Features(a)	Front-End Sales Charges(b)	Contingent Deferred Sales Charges (CDSCs)(b)	Sales Charge Reductions/Waivers	Maximum Distribution and/or Service (12b-1) Fees(c)
	of the Transfer Agent; and (viii) commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Adv shares within such platform. Minimum Initial Investment: None, except in the case of (viii) above, which is $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts)
Class C	Eligibility: Available to the general public for investment Minimum Initial Investment: $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts) Conversion Feature: Yes. Effective April 1, 2021, Class C shares generally automatically convert to Class A shares of the same Fund in the month of or the month following the 8-year anniversary of the Class C shares purchase date. Prior to April 1, 2021, Class C shares generally automatically converted to Class A shares of the same Fund in the month of or the month following the 10-year anniversary of the Class C shares purchase date.(a)	None	1.00% on certain investments redeemed within one year of purchase	Waivers: yes, on Fund distribution reinvestments. For additional waivers, see Choosing a Share Class — CDSC Waivers – Class A and Class C Financial intermediary-specific CDSC waivers are also available, see Appendix A	Distribution Fee: 0.75% Service Fee: 0.25%
Class Inst	Eligibility: Available only to certain eligible investors, which are subject to different minimum investment requirements, ranging from $0 to $2,000, including investors who purchase Fund shares through commissionable brokerage platforms where the financial intermediary holds the shares in an omnibus account and, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst shares within such platform; closed to (i) accounts of financial intermediaries that clear Fund share transactions for their client or customer accounts through designated financial intermediaries and their mutual fund	None	None	N/A	None

28 Prospectus 2022

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Choosing a Share Class (continued)

Share Class	Eligible Investors; Minimum Initial Investments; Conversion Features(a)	Front-End Sales Charges(b)	Contingent Deferred Sales Charges (CDSCs)(b)	Sales Charge Reductions/Waivers	Maximum Distribution and/or Service (12b-1) Fees(c)
	trading platforms that have been given specific written notice from the Transfer Agent of the termination of their eligibility for new purchases of Class Inst shares and (ii) omnibus group retirement plans, subject to certain exceptions(d) Minimum Initial Investment: See Eligibility above
Class Inst2	Eligibility: Available only to (i) certain registered investment advisers and family offices that clear Fund share transactions for their client or customer accounts through designated financial intermediaries and their mutual fund trading platforms that have been granted specific written authorization from the Transfer Agent with respect to Class Inst2 eligibility apart from selling, servicing or similar agreements; (ii) omnibus retirement plans(d); (iii) health savings accounts, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst2 shares within such platform and that Fund shares are held in an omnibus account; and (iv) institutional investors that are clients of the Columbia Threadneedle Global Institutional Distribution Team that invest in Class Inst2 shares for their own account through platforms approved by the Distributor or an affiliate thereof to offer and/or service Class Inst2 shares within such platform. Minimum Initial Investment: None	None	None	N/A	None
Class Inst3	Eligibility: Available to: (i) group retirement plans that maintain plan-level or omnibus accounts with the Fund(d); (ii) institutional investors that are clients of the Columbia Threadneedle Global Institutional Distribution Team that invest in Class Inst3 shares for their own account through platforms approved by the Distributor or an affiliate thereof to offer and/or service Class Inst3 shares within such platform; (iii) collective trust funds; (iv) affiliated or unaffiliated mutual funds (e.g., funds operating as funds-of-funds); (v) fee-based platforms of financial intermediaries (or the clearing intermediary they trade through) that have an agreement with the	None	None	N/A	None

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Columbia Acorn® Fund

Choosing a Share Class (continued)

Share Class	Eligible Investors; Minimum Initial Investments; Conversion Features(a)	Front-End Sales Charges(b)	Contingent Deferred Sales Charges (CDSCs)(b)	Sales Charge Reductions/Waivers	Maximum Distribution and/or Service (12b-1) Fees(c)
	Distributor or an affiliate thereof that specifically authorizes the financial intermediary to offer and/or service Class Inst3 shares within such platform, provided also that Fund shares are held in an omnibus account; (vi) commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst3 shares within such platform and that Fund shares are held in an omnibus account; (vii) health savings accounts, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst3 shares within such platform and that Fund shares are held in an omnibus account; and (viii) bank trust departments, subject to an agreement with the Distributor that specifically authorizes offering Class Inst3 shares and provided that Fund shares are held in an omnibus account. In each case above where noted that Fund shares are required to be held in an omnibus account, the Distributor, may, in its discretion, determine to waive this requirement. Minimum Initial Investment: No minimum for the eligible investors described in (i), (iii), (iv) and (v) above; $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts) for the eligible investors described in (vi) above; and $1 million for all other eligible investors, unless waived in the discretion of the Distributor
Class R	Eligibility: Available only to eligible retirement plans, health savings accounts and, in the sole discretion of the Distributor, other types of retirement accounts held through platforms maintained by financial intermediaries approved by the Distributor Minimum Initial Investment: None	None	None	N/A	Distribution Fee: 0.50%

(a) For more information on the conversion of Class C shares to Class A shares, see Choosing a Share Class — Sales Charges and Commissions — Class C Shares —Conversion to Class A Shares.

(b) For more information on applicable sales charges, see Choosing a Share Class — Sales Charges and Commissions, and for information about certain exceptions to these sales charges, see Choosing a Share Class — Reductions/Waivers of Sales Charges.

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(c) These are the maximum applicable distribution and/or service fees under the Fund’s Rule 12b-1 plan. Because these fees are paid out of Fund assets on an ongoing basis, over time these fees will increase the cost of your investment and may cost you more than paying other types of distribution and/or service fees. For more information on distribution and service fees, see Choosing a Share Class — Distribution and Service Fees.

(d) These share classes are closed to new accounts generally or to new accounts of certain categories of investors, subject to certain conditions, as summarized below and described in more detail under Buying, Selling and Exchanging Shares — Buying Shares — Eligible Investors:

•  Class Inst Shares: Financial intermediaries that clear Fund share transactions through designated financial intermediaries and their mutual fund trading platforms that were given specific written notice from the Transfer Agent of the termination, effective March 29, 2013, of their eligibility for new purchases of Class Inst shares and omnibus retirement plans are not permitted to establish new Class Inst accounts, subject to certain exceptions. Omnibus retirement plans that opened and, subject to exceptions, funded a Class Inst account as of close of business on March 28, 2013, and have continuously held Class Inst shares in such account after such date, may generally continue to make additional purchases of Class Inst shares, open new Class Inst accounts and add new participants. In certain circumstances and in the sole discretion of the Distributor, omnibus retirement plans affiliated with a grandfathered plan may also open new Class Inst accounts. Accounts of financial intermediaries (other than omnibus retirement plans) that clear Fund share transactions for their client or customer accounts through designated financial intermediaries and their mutual fund trading platforms are not permitted to establish new Class Inst accounts or make additional purchases of Class Inst shares (other than through reinvestment of distributions).

•  Class Inst2 Shares. Shareholders with Class Inst2 accounts funded before November 8, 2012 who do not satisfy the current eligibility criteria for Class Inst2 shares may not establish new Class Inst2 accounts but may continue to make additional purchases of Class Inst2 shares in existing accounts. In addition, investment advisory programs and similar programs that opened a Class Inst2 account as of May 1, 2010, and continuously hold Class Inst2 shares in such account after such date, may generally not only continue to make additional purchases of Class Inst2 shares but also open new Class Inst2 accounts and add new shareholders in the program.

•  Class Inst3 Shares: Shareholders with Class Inst3 accounts funded before November 8, 2012 who do not satisfy the current eligibility criteria for Class Inst3 shares may not establish new accounts for such share class but may continue to make additional purchases of Class Inst3 shares in existing accounts.

Sales Charges and Commissions

Sales charges, commissions, and distribution fees compensate financial intermediaries (typically your financial advisor) for selling shares to you, and service fees compensate financial intermediaries for maintaining and servicing the shares held in your account with them. Distribution and service fees are discussed in a separate sub-section below. Depending on which share class you choose and the financial intermediary through which you purchase your shares, you may pay these charges at potentially different levels at the outset as a front-end sales charge, at the time you sell your shares as a CDSC and/or over time in the form of distribution and/or service fees. You may be required to pay brokerage commissions and other fees to financial intermediaries when transacting in any class of Fund shares, including those that do not assess any front-end sales charge, contingent deferred sales charge, or other asset-based fee for sales or distribution. Such brokerage commissions and other fees are set by the financial intermediary.

As described in more detail below, Class A shares have a front-end sales charge, which is deducted from your purchase price when you buy your shares, and results in a smaller dollar amount being invested in the Fund than the purchase price you pay (unless you qualify for a waiver or reduction of the sales charge). The Fund’s other share classes do not have a front-end sales charge, so the full amount of your purchase price is invested in those classes. Class A shares have lower ongoing distribution and/or service fees than Class C and Class R shares of the Fund. Over time, Class C and Class R shares can incur distribution and/or service fees that are equal to or more than the front-end sales charge and the distribution and/or service fees you would pay for Class A shares. Although the full amount of your purchase price of Class C and Class R shares is invested in a Fund, your return on this money will be reduced by the expected higher annual expenses of Class C and Class R shares. In this regard, note that effective April 1, 2021, Class C shares will generally automatically convert to Class A shares of the same Fund in the month of or the month following the 8-year anniversary of the Class C shares purchase date (prior to April 1, 2021, the 10-year anniversary of such date). The Fund may convert Class C shares held through a financial intermediary to Class A shares sooner in connection with the withdrawal of Class C shares of the Fund from the financial intermediary’s platform or accounts. No sales charge or other charges will apply in connection with such conversions, and the conversions are free from U.S. federal income tax. Once your Class C shares convert to Class A shares, your total returns from an investment in the Fund may increase as a result of the lower operating costs of Class A shares. Class Adv, Class Inst, Class Inst2 and Class Inst3 shares of the Fund do not have distribution and/or service fees.

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Whether the ultimate cost is higher for one share class over another depends on the amount you invest, how long you hold your shares, the fees (i.e., sales charges) and expenses of the class and whether you are eligible for reduced or waived sales charges, if available. You are responsible for choosing the share class most appropriate for you after taking into account your share class eligibility, class-specific features, and any applicable reductions in, or waivers of, sales charges. For more information, see Choosing a Share Class – Reductions/Waivers of Sales Charges. We encourage you to consult with a financial advisor who can help you with your investment decisions. Please contact your financial intermediary for more information about services, fees and expenses, and other important information about investing in the Fund, as well as with any questions you may have about your investing options. In all instances, it is your responsibility to notify your financial intermediary or (for Direct-at-Fund Accounts, as defined below) the Fund at the time of purchase of any relationship or other facts that may qualify you for sales charge waivers or discounts.

Class A Shares — Front-End Sales Charge

Unless your purchase qualifies for a waiver (e.g., you buy the shares through reinvested Fund dividends or distributions or subject to an applicable financial intermediary-specific waiver), you will pay a front-end sales charge when you buy Class A shares, resulting in a smaller dollar amount being invested in a Fund than the purchase price you pay. The Class A shares sales charge is waived on Class C shares converted to Class A shares. For more information about sales charge waivers and reduction opportunities, see Choosing a Share Class — Reductions/Waivers of Sales Charges and Appendix A.

The Distributor receives the sales charge and re-allows (or pays) a portion of the sales charge to the financial intermediary through which you purchased the shares. The Distributor retains the balance of the sales charge.

The front-end sales charge you will pay on Class A shares:

■ depends on the amount you are investing (generally, the larger the investment, the smaller the percentage sales charge), and

■ is based on the total amount of your purchase and the value of your account (and any other accounts eligible for aggregation of which you or your financial intermediary notifies the Fund).

The table below presents the front-end sales charge as a percentage of both the offering price and the net amount invested.

Class A Shares — Front-End Sales Charge — Breakpoint Schedule
Breakpoint Schedule For:	Dollar amount of shares bought(a)	Sales charge as a % of the offering price(b)	Sales charge as a % of the net amount invested(b)	Amount retained by or paid to financial intermediaries as a % of the offering price
Class A Shares	$0–$49,999	5.75%	6.10%	5.00%
	$50,000–$99,999	4.50%	4.71%	3.75%
	$100,000–$249,999	3.50%	3.63%	3.00%
	$250,000–$499,999	2.50%	2.56%	2.15%
	$500,000–$999,999	2.00%	2.04%	1.75%
	$1,000,000 or more	0.00%	0.00%	0.00%(c)

(a) Purchase amounts and account values may be aggregated among all eligible Fund accounts for the purposes of this table. See Choosing a Share Class — Reductions/Waivers of Sales Charges for a discussion of account value aggregation.

(b) Because the offering price is calculated to two decimal places, the dollar amount of the sales charge as a percentage of the offering price and your net amount invested for any particular purchase of Fund shares may be higher or lower depending on whether downward or upward rounding was required during the calculation process. Purchase price includes the sales charge.

(c) For information regarding cumulative commissions paid to your financial intermediary when you buy $1 million or more of Class A shares of a Fund, see Class A Shares — Commissions below.

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Class A Shares — CDSC

In some cases, you'll pay a CDSC if you sell Class A shares that you purchased without a front-end sales charge.

■ If you purchased Class A shares without an initial sales charge because your accounts aggregated between $1 million and $50 million at the time of purchase, you will incur a CDSC if you redeem those shares within 18 months after purchase, which is charged as follows: 1.00% CDSC if shares are redeemed within 12 months after purchase; and 0.50% CDSC if shares are redeemed more than 12, but less than 18, months after purchase.

■ Subsequent Class A share purchases that bring your aggregate account value to $1 million or more (but less than $50 million) will also be subject to a CDSC if you redeem them within the time periods noted above.

Class A Shares — Commissions

The Distributor may pay your financial intermediary an up-front commission when you buy Class A shares. The Distributor generally funds the commission through the applicable sales charge you paid. For more information, see Class A Shares — Front-End Sales Charge above.

The Distributor may also pay your financial intermediary a cumulative commission when you buy Class A shares in amounts not subject to a front-end sales charge, according to the following schedules (assets initially purchased into Class A shares of Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund and Columbia U.S. Treasury Index Fund that were purchased without the application of a front-end sales charge are excluded for purposes of calculating a financial intermediary’s commission under these schedules):

Class A Shares — Commission Schedule (Paid by the Distributor to Financial Intermediaries)
Purchase Amount	Commission Level* (as a % of net asset value per share)
$1 million – $2,999,999	1.00%
$3 million – $49,999,999	0.50%
$50 million or more	0.25%

* The commission level applies to the applicable asset level; therefore, for example, for a purchase of $5 million, the Distributor would pay a commission of 1.00% on the first $2,999,999 and 0.50% on the balance.

Class C Shares — Front-End Sales Charge

You do not pay a front-end sales charge when you buy Class C shares, but you may pay a CDSC when you sell Class C shares. Although Class C shares do not have a front-end sales charge, over time Class C shares can incur distribution and/or service fees that are equal to or more than the front-end sales charge and distribution and/or service fees you would pay for Class A shares. Thus, although the full amount of your purchase of Class C shares is invested in a Fund, any positive investment return on this money may be partially or fully offset by the expected higher annual expenses of Class C shares.

Class C Shares — Conversion to Class A Shares

Effective April 1, 2021, Class C shares of a Fund generally automatically convert to Class A shares of the same Fund in the month of or the month following the 8-year anniversary of the Class C shares purchase date. Prior to April 1, 2021, Class C shares of a Fund generally automatically converted to Class A shares of the same Fund in the month of or in the month following the 10-year anniversary of the Class C shares purchase date. Class C shares held through a financial intermediary in an omnibus account will be converted (pursuant to the financial intermediary’s Class C conversion policy, including those disclosed in Appendix A, which may differ from the Fund’s policy described here) provided that the intermediary is able to track individual shareholders’ holding periods. It is the financial intermediary's (and not the Fund's) responsibility to keep records and to ensure that the shareholder holding period is calculated properly. Not all financial intermediaries are able to track individual shareholders' holding periods. For example, group retirement plans held through third-party intermediaries that hold Class C shares in an omnibus account may not track participant level share lot aging. Please consult with your financial intermediary about your

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Columbia Acorn® Fund

Choosing a Share Class (continued)

eligibility for Class C share conversion. The Fund may convert Class C shares held through a financial intermediary to Class A shares sooner in connection with the withdrawal of Class C shares of the Fund from the financial intermediary's platform or accounts. Once your Class C shares convert to Class A shares, your total returns from an investment in the Fund may increase as a result of the lower operating costs of Class A shares.

The following rules apply to the automatic conversion of Class C shares to Class A shares:

■ Class C share accounts that are Direct-at-Fund Accounts and Networked Accounts for which the Transfer Agent (and not your financial intermediary) sends you Fund account transaction confirmations and statements, convert on or about the 15th day of the month (if the 15th is not a business day, then the next business day thereafter) that they become eligible for automatic conversion provided that the Fund has records that Class C shares have been held for the requisite time period.

■ For purposes of determining the month when your Class C shares are eligible for conversion, the start of the holding period is the first day of the month in which your purchase was made. Your financial intermediary may choose a different day of the month to convert Class C shares. Please contact your financial intermediary for more information on calculating the holding period.

■ Any shares you received from reinvested distributions on these shares generally will convert to Class A shares at the same time.

■ You’ll receive the same dollar value of Class A shares as the Class C shares that were automatically converted. Class C shares that you received from an exchange of Class C shares of another Fund will convert based on the day you bought the original shares.

■ In addition to the above automatic conversion of Class C to Class A shares policy, the Transfer Agent seeks to convert Class C shares as soon as administratively feasible, regardless of how long such shares have been owned, to Class A shares of the same Fund for Direct-at-Fund Accounts (as defined below) that do not or no longer have a financial intermediary assigned to them. Direct-at-Fund Accounts that do not have a financial intermediary assigned to them are not permitted to purchase Class C shares; Class C share purchase orders received by Direct-at-Fund Accounts that do not have a financial intermediary assigned to the account will automatically be invested in Class A shares of the same Fund.

■ No sales charge or other charges apply in connection with these automatic conversions, and the conversions are free from U.S. federal income tax.

Class C Shares — CDSC

You will pay a CDSC of 1.00% if you redeem Class C shares within 12 months of buying them unless you qualify for a waiver of the CDSC (e.g., the shares you are selling were purchased with reinvested Fund distributions). Redemptions of Class C shares are not subject to a CDSC if redeemed after 12 months. For more information, see Choosing a Share Class — Reductions/Waivers of Sales Charges.

Class C Shares — Commissions

Although there is no front-end sales charge when you buy Class C shares, the Distributor makes an up-front payment (which includes a sales commission and an advance of service fees) directly to your financial intermediary of up to 1.00% of the NAV per share when you buy Class C shares. A portion of this payment may be passed along to your financial advisor. The Distributor seeks to recover this payment through distribution fees of up to 0.75% and shareholder service fees of up to 0.25% it receives under the Fund's Rule 12b-1 plan during the first 12 months following the sale of Class C shares, and any applicable CDSC when you sell your shares. For more information, see Choosing a Share Class — Distribution and Service Fees.

Reductions/Waivers of Sales Charges

The availability of certain sales charge waivers and discounts will depend on whether you purchase your shares directly from the Fund (i.e., a Direct-at-Fund Account, as defined below) or through a financial intermediary. Financial intermediaries may have different policies and procedures regarding the availability of front-end sales charge and/or CDSC waivers. In all instances, it is your responsibility to notify your financial intermediary or (for Direct-at-Fund

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Accounts, as defined below) the Fund at the time of purchase of any relationship or other facts that may qualify you for sales charge waivers or discounts. In order to obtain waivers and discounts not available through a particular financial intermediary, shareholders will have to purchase Fund shares directly from the Fund (if permitted) or through a different financial intermediary. For a description of financial intermediary-specific sales charge reductions and/or waivers, see Appendix A.

Class A Shares Front-End Sales Charge Reductions

The Fund makes available two means of reducing the front-end sales charge that you may pay when you buy Class A shares of a Fund. These types of sales charge reductions are also referred to as breakpoint discounts.

First, through the right of accumulation (ROA), you may combine the value of eligible accounts (as described in the Eligible Accounts section below) maintained by you and members of your immediate family to reach a breakpoint discount level and apply a lower front-end sales charge to your purchase. To calculate the combined value of your eligible Fund accounts in the particular class of shares, the Fund will use the current public offering price per share. For purposes of obtaining a breakpoint discount through ROA, you may aggregate your and your “immediate family” members' ownership (as described in the FUNDamentals box below) of certain classes of shares held in certain account types, as described in the Eligible Accounts section below.

Second, by making a statement of intent to purchase additional shares (commonly referred to as a letter of intent (LOI)), you may pay a lower sales charge on all purchases of Class A shares made within 13 months after the date of your LOI. Your LOI must state the aggregate amount of purchases you intend to make in that 13-month period, which must be at least enough to reach the first (or next) breakpoint of the Fund. The required form of LOI may vary by financial intermediary, so please contact them directly for more information. Five percent of the purchase commitment amount will be placed in escrow. At the end of the 13-month period, the shares will be released from escrow, provided that you have invested the commitment amount. If you do not invest the commitment amount by the end of the 13 months, the remaining amount of the unpaid sales charge will be redeemed from the escrowed shares and the remaining balance released from escrow. To calculate the total value of the purchases you've made under an LOI, the Fund will use the historic cost (i.e., dollars invested and not current market value) of the shares held in each eligible account; reinvested dividends or capital gains, or purchases made through the reinstatement privilege do not count as purchases made under an LOI. For purposes of making an LOI to purchase additional shares, you may aggregate eligible shares owned by you or your immediate family members in eligible accounts, valued as of the day immediately before the initiation of your LOI.

You must request the reduced sales charge (whether through ROA or an LOI) when you buy shares. If you do not complete and file an LOI, or do not request the reduced sales charge at the time of purchase, you will not be eligible for the reduced sales charge. To obtain a breakpoint discount, you must notify your financial intermediary in writing at the time you buy your shares of each eligible account maintained by you and members of your immediate family, including accounts maintained through different financial intermediaries. You and your financial intermediary are responsible for ensuring that you receive discounts for which you are eligible. Please contact your financial intermediary with questions regarding application of the eligible discount to your account. You may be asked by your financial intermediary (or by the Fund if you hold your account directly with the Fund) for account statements or other records to verify your discount eligibility for new and subsequent purchases, including, when applicable, records for accounts opened with a different financial intermediary and records of accounts established by members of your immediate family.

The sales charge reductions available to investors who purchase and hold their Fund shares through different financial intermediaries may vary. For a description of such financial intermediary-specific sales charge reductions, see Appendix A.

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Choosing a Share Class (continued)

 FUNDamentals

Your “Immediate Family” and Account Value Aggregation

For purposes of obtaining a breakpoint discount for Class A shares, the value of your account will be deemed to include the value of all applicable shares in eligible Fund accounts that are held by you and your “immediate family,” which includes your spouse, domestic partner, parent, step-parent, legal guardian, child under 21, step-child under 21, father-in-law and mother-in-law, provided that you and your immediate family members share the same mailing address. Any Fund accounts linked together for account value aggregation purposes as of the close of business on September 3, 2010 will be permitted to remain linked together. Group retirement plan accounts are valued at the retirement plan level.

Eligible Accounts

The following accounts are eligible for account value aggregation as described above, provided that they are invested in Class A (excluding, in the case of Direct-at-Fund Accounts, Funds that do not assess a front-end sales charge, including Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund and Columbia U.S. Treasury Index Fund, unless such shares were purchased via an exchange from Class A shares of a Fund on which you paid the Class A share applicable front-end sales charge), Class C, Class E, Class Inst or Class V shares of a Fund, or non-retirement plan accounts invested in Class Adv, Class Inst2 or Class Inst3 shares of a Fund: individual or joint accounts; Roth and traditional Individual Retirement Accounts (IRAs); Simplified Employee Pension accounts (SEPs), Savings Investment Match Plans for Employees of Small Employers accounts (SIMPLEs) and Tax Sheltered Custodial Accounts (TSCAs); Uniform Gifts to Minors Act (UGMA)/Uniform Transfers to Minors Act (UTMA) accounts for which you, your spouse, or your domestic partner is parent or guardian of the minor child; revocable trust accounts for which you or an immediate family member, individually, is the beneficial owner/grantor; accounts held in the name of your, your spouse’s, or your domestic partner’s sole proprietorship or single owner limited liability company or S corporation; qualified retirement plan assets, provided that you are the sole owner of the business sponsoring the plan, are the sole participant (other than a spouse) in the plan, and have no intention of adding participants to the plan; and investments in wrap accounts.

The following accounts are not eligible for account value aggregation as described above: accounts of pension and retirement plans with multiple participants, such as 401(k) plans (which are combined to reduce the sales charge for the entire pension or retirement plan and therefore are not used to reduce the sales charge for your individual accounts); investments in 529 plans, donor advised funds, variable annuities, variable insurance products or managed separate accounts; charitable and irrevocable trust accounts; accounts holding shares of money market funds that used the Columbia brand before May 1, 2010; accounts invested in Class R shares of a Fund; and retirement plan accounts invested in Class Adv, Class Inst2 or Class Inst3 shares of a Fund.

Additionally, direct purchases of shares of Columbia Government Money Market Fund may not be aggregated for account value aggregation purposes; however, shares of Columbia Government Money Market Fund acquired by exchange from other Columbia Funds that assess a sales charge may be included in account value aggregation.

Class A Shares Front-End Sales Charge Waivers

There are no front-end sales charges on reinvested Fund distributions. The Class A shares sales charge is waived on conversions of Class C shares to Class A shares. The Distributor may waive front-end sales charges on purchases of Class A shares of the Funds by certain categories of investors, including Board members, certain employees of financial intermediaries, Fund portfolio managers, certain partners and employees of outside legal counsel to the Funds or the Board, separate accounts of an insurance company exempt from registration as an investment company under Section 3(c)(11) of the 1940 Act, registered broker-dealer firms that have an agreement with the Distributor purchasing Fund shares for their investment account only, and qualified employee benefit plan rollovers to Class A

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shares in the same Fund (see Appendix S to the SAI for details). For a more complete description of categories of investors who may purchase Class A shares of the Funds at NAV, without payment of any front-end sales charge that would otherwise apply, see Appendix S to the SAI.

In addition, certain types of purchases of Class A shares may be made at NAV. The Distributor may waive front-end sales charges on (i) purchases (including exchanges) of Class A shares in accounts of financial intermediaries that have entered into agreements with the Distributor to offer Fund shares to self-directed investment brokerage accounts that may or may not charge a transaction fee to customers; (ii) exchanges of Class Inst shares of a Fund for Class A shares of the Fund; (iii) purchases of Class A shares on brokerage mutual fund-only platforms of financial intermediaries that have an agreement with the Distributor that specifically authorizes the offering of Class A shares within such platform; (iv) purchases through certain wrap fee or other products or programs that involve fee-based compensation arrangements that have, or clear trades through a financial intermediary that has, a selling agreement with the Distributor; (v) purchases through state sponsored 529 Plans; (vi) purchases through banks, trust companies, and thrift institutions acting as fiduciaries; (vii) purchases through certain employee benefit plans and certain qualified deferred compensation plans; and (viii) purchases of Class A shares in Direct-at-Fund Accounts (as defined below) that do not have a financial intermediary assigned to them. For a more complete description of these eligible transactions, see Appendix S to the SAI.

The sales charge waivers available to investors who purchase and hold their Fund shares through different financial intermediaries may vary. For a description of such financial intermediary-specific sales charge waivers, see Appendix A.

CDSC Waivers – Class A and Class C

You may be able to avoid an otherwise applicable CDSC when you sell Class A or Class C shares of the Fund. This could happen because of the way in which you originally invested in the Fund, because of your relationship with the Funds or for other reasons. For example, the CDSC will be waived on redemptions of shares: in the event of the shareholder's death; for which no sales commission or transaction fee was paid to an authorized financial intermediary at the time of purchase; purchased through reinvestment of dividends and capital gain distributions; that result from required minimum distributions taken from retirement accounts due to the shareholder reaching the qualified age based on applicable IRS regulations; that result from returns of excess contributions made to retirement plans or individual retirement accounts (subject to certain conditions); initially purchased by an employee benefit plan (for Class A shares) and that are not connected with a plan level termination (for Class C shares); in connection with the Fund's Small Account Policy (which is described in Buying, Selling and Exchanging Shares — Transaction Rules and Policies); held within Direct-at-Fund Accounts that do not have a financial intermediary assigned to them; and by certain other investors and in certain other types of transactions or situations. Restrictions may apply to certain accounts and certain transactions. The Distributor may, in its sole discretion, authorize the waiver of the CDSC for additional classes of investors. The Fund may change or cancel these terms at any time. Any change or cancellation applies only to future purchases. For a more complete description of the available waivers of the CDSC on redemptions of Class A or Class C shares, see Appendix S to the SAI.

The sales charge waivers available to investors who purchase and hold their Fund shares through different financial intermediaries may vary. For a description of such financial intermediary-specific sales charge waivers, see Appendix A.

Repurchases (Reinstatements)

As noted in the table below, you can redeem shares of certain classes (see Redeemed Share Class below) and use such redemption proceeds to buy shares of the Corresponding Repurchase Class without paying an otherwise applicable sales charge and/or CDSC (other than, in the case of Direct-at-Fund Accounts, redemptions from Funds that do not assess a front-end sales charge, including Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund and Columbia U.S. Treasury Index Fund, unless such shares were purchased via an exchange from Class A shares of a Fund on which you paid the Class A share applicable front-end sales charge) within 90 days, up to the amount of the redemption proceeds.

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Repurchases (Reinstatements)
Redeemed Share Class	Corresponding Repurchase Class
Class A	Class A
Class C	Class C

Any CDSC paid upon redemption of your Class A or Class C shares of a Fund will not be reimbursed.

To be eligible for the repurchase (or reinstatement) privilege, the purchase must be made into an account for the same owner, but does not need to be into the same Fund from which the shares were sold. The Transfer Agent, Distributor or their agents must receive a written reinstatement request from you or your financial intermediary within 90 days after the shares are redeemed. The purchase of the Corresponding Repurchase Class (as noted in the table above) through this repurchase (or reinstatement) privilege will be made at the NAV of such shares next calculated after the request is received in “good form.” Systematic withdrawals and purchases are excluded from this policy.

Restrictions and Changes in Terms and Conditions

Restrictions may apply to certain accounts and certain transactions. The Funds and/or the Distributor may change or cancel these terms and conditions at any time. Unless you provide your financial intermediary with information in writing about all of the factors that may count toward available reductions or waivers of an applicable sales charge, there can be no assurance that you will receive all of the reductions and waivers for which you may be eligible. To the extent your Fund account is held directly with the Fund, you should provide this information to the Fund when placing your purchase or redemption order. Please see Appendix A to this prospectus and Appendix S of the SAI for more information about sales charge waivers.

Distribution and Service Fees

The Board has approved, and the Columbia Acorn Funds have adopted, a distribution plan pursuant to Rule 12b-1 under the 1940 Act that sets the distribution and/or service fees that are periodically deducted from the Funds’ assets. These fees are calculated daily, may vary by share class and are intended to compensate the Distributor and/or eligible financial intermediaries for, with regard to distribution fees, selling Fund shares and, with regard to service fees, directly or indirectly providing services to shareholders. Because the fees are paid out of the Fund's assets on an ongoing basis, they will increase the cost of your investment over time.

The table below shows the maximum annual distribution and/or service fees (as an annual percentage of average daily net assets) and the combined amount of such fees applicable to each share class of the Columbia Acorn Funds:

	Distribution Fee	Service Fee	Combined Total
Class A	None	0.25%	0.25%
Class Adv	None	None	None
Class C	0.75%	0.25%	1.00%
Class Inst	None	None	None
Class Inst2	None	None	None
Class Inst3	None	None	None
Class R	0.50%	None	0.50%

The distribution and/or service fees for Class A, Class C, and Class R shares, as applicable, are subject to the requirements of Rule 12b-1 under the 1940 Act. The Distributor may retain these fees otherwise payable to financial intermediaries if the amounts due are below an amount determined by the Distributor in its sole discretion.

For Class A shares, the Distributor begins to pay these fees immediately after purchase, except in the following case, in which the Distributor begins to pay these fees 12 months after purchase: a purchase of Class A shares of $1 million or more that pay a Class A up-front commission to your financial intermediary and the financial intermediary has opted to receive such commission. The Distributor’s policy to otherwise begin to pay these fees immediately on

38 Prospectus 2022

Columbia Acorn® Fund

Choosing a Share Class (continued)

Class A shares also applies to purchases of funds that do not pay an up-front sales commission on Class A shares, which includes Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund and Columbia U.S. Treasury Index Fund. For Class C shares, the Distributor begins to pay these fees 12 months after purchase. However, for Class C shares, financial intermediaries may opt to decline the up-front payment described in Choosing a Share Class – Sales Charges and Commissions – Class C Shares – Commissions and instead may receive these fees immediately after purchase. If the intermediary opts to receive the up-front payment, the Distributor retains the distribution and service fee for the first 12 months following the sale of Class C shares in order to recover the up-front payment made to financial intermediaries and to pay for other related expenses. For Class R shares, the Distributor begins to pay these fees immediately after purchase.

If you maintain shares of the Fund directly with the Fund, without working with a financial advisor or other financial intermediary, distribution and service fees may be retained by the Distributor as payment or reimbursement for incurring certain distribution and shareholder service related expenses.

Over time, these distribution and/or service fees will reduce the return on your investment and may cost you more than paying other types of sales charges. The Fund will pay these fees to the Distributor and/or to eligible financial intermediaries for as long as the distribution plan continues in effect, which is expected to be indefinitely. However, the Fund may reduce or discontinue payments at any time. Your financial intermediary may also charge you other additional fees for providing services to your account, which may be different from those described here.

Financial Intermediary Compensation

The Distributor, the Investment Manager and their affiliates make payments, from their own resources, to financial intermediaries, including other Ameriprise Financial affiliates, for marketing/sales support services relating to the Funds (Marketing Support Payments). Such payments are generally based upon one or more of the following factors: average net assets of the Funds attributable to that financial intermediary; gross sales of the Funds attributable to that financial intermediary; reimbursement of ticket charges (fees that a financial intermediary charges its representatives for effecting transactions in Fund shares); or a negotiated lump sum payment. While the financial arrangements may vary for each financial intermediary, Marketing Support Payments to any one financial intermediary are generally between 0.01% and 0.40% on an annual basis for payments based on average net assets of the Fund attributable to the financial intermediary, and between 0.05% and 0.25% on an annual basis for firms receiving a payment based on gross sales of the Funds attributable to the financial intermediary. The Distributor, the Investment Manager and their affiliates make payments with respect to a Fund or the Columbia Funds generally on a basis other than those described above or in larger amounts when dealing with certain financial intermediaries. Not all financial intermediaries receive Marketing Support Payments. The Distributor, the Investment Manager and their affiliates do not make Marketing Support Payments with respect to Class Inst3 shares of the Columbia Acorn Funds.

In addition, the Transfer Agent has certain arrangements in place to compensate financial intermediaries, including other Ameriprise Financial affiliates, that hold Fund shares through networked and omnibus accounts, including omnibus retirement plans, for services that they provide to beneficial Fund shareholders (Shareholder Services). Shareholder Services and related fees vary by financial intermediary and according to distribution channel and may include sub-accounting, sub-transfer agency, participant recordkeeping, shareholder or participant reporting, shareholder or participant transaction processing, maintenance of shareholder records, preparation of account statements and provision of customer service, and are not intended to include services that are primarily intended to result in the sale of Fund shares. Payments for Shareholder Services vary by financial intermediary and according to distribution channel, but generally are not expected, with certain limited exceptions, to exceed 0.40% of the average aggregate value of the Fund’s shares. Payments to financial intermediaries in excess of the amounts paid by the Fund are borne by the Distributor, the Investment Manager and/or their affiliates.

Prospectus 2022 39

Columbia Acorn® Fund

Choosing a Share Class (continued)

Generally, each Fund in the Columbia Acorn Family of Funds compensates the Transfer Agent for payments made for Shareholder Services, for each share class except Class Inst3. Effective July 1, 2017, the Columbia Acorn Funds compensate the Transfer Agent for payments made for Shareholder Services as follows:

Financial Intermediary Distribution Channel	Fee Rate
Retirement	up to 0.18% of Fund assets held by intermediaries or platforms charging an asset-based fee, or $18 per account held by intermediaries or platforms charging a per account fee
Fund supermarket transaction fee (TF)	up to 0.12% of Fund assets held by intermediaries or platforms charging an asset-based fee, or $16 per account held for intermediaries or platforms charging a per account fee
Fund supermarket no-transaction fee (NTF)	up to 0.18% of Fund assets held by intermediaries or platforms charging an asset-based fee, or $18 per account held by intermediaries or platforms charging a per account fee
Bank	up to 0.10% of Fund assets held by intermediaries or platforms charging an asset-based fee, or $20 per account held by intermediaries or platforms charging a per account fee
Broker-dealer	up to 0.13% of Fund assets held by intermediaries or platforms charging an asset-based fee, or $16 per account held by intermediaries or platforms charging a per account fee

With respect to Class Inst2 and Class Inst3 shares of the Fund, total annual compensation payable to the Transfer Agent may not exceed, respectively, 0.07% and 0.02% of the average daily net assets of the Class. For additional details about the application of the Columbia Acorn Funds’ fee limits, please refer to the SAI.

The Transfer Agent does not pay financial intermediaries for Shareholder Services, and the Fund does not compensate the Transfer Agent for any Shareholder Services provided by financial intermediaries with respect to Class Inst3 shares of the Columbia Acorn Funds. The Fund believes that the fee levels paid to the Transfer Agent are reasonably related to the Shareholder Services provided, but payments may vary and there can be no assurance that the Fund will be able to identify with specificity the costs or particular Shareholder Services for which compensation is paid.

In addition to the payments described above, the Distributor, the Investment Manager and their affiliates typically make other payments or allow promotional incentives to certain broker-dealers to the extent permitted by the Securities and Exchange Commission (the SEC) and Financial Industry Regulatory Authority (FINRA) rules and by other applicable laws and regulations.

Amounts paid by the Distributor, the Investment Manager and their affiliates are paid out of their own resources and do not increase the amount paid by you or the Fund. You can find further details in the SAI about the payments made by the Distributor, the Investment Manager and their affiliates, as well as a list of the financial intermediaries, including Ameriprise Financial affiliates, to which the Distributor and the Investment Manager have agreed to make Marketing Support Payments and pay Shareholder Services fees.

Your financial intermediary may charge you fees and commissions in addition to those described in this prospectus. You should consult with your financial intermediary and review carefully any disclosure your financial intermediary provides regarding its services and compensation. Depending on the financial arrangement in place at any particular time, a financial intermediary and its financial advisors may have a conflict of interest or financial incentive for recommending the Fund or a particular share class over others.

40 Prospectus 2022

Columbia Acorn® Fund

Buying, Selling and Exchanging Shares

Share Price Determination

The price you pay or receive when you buy, sell or exchange shares is the Fund's next determined net asset value (or NAV) per share for a given share class. The Fund calculates the NAV per share for each class of shares of the Fund at the end of each business day, with the value of the Fund's shares based on the total value of all of the securities and other assets that it holds as of such specified time.

 FUNDamentals

NAV Calculation

Each of the Fund's share classes calculates its NAV per share as follows:

NAV per share =  (Value of assets of the share class) – (Liabilities of the share class)
Number of outstanding shares of the class

 FUNDamentals

Business Days

A business day is any day that the New York Stock Exchange (NYSE) is open. A business day ends at (i) the scheduled close of the NYSE for such day (usually 4:00 p.m. Eastern Time or such other time as the NYSE may schedule), (ii) the scheduled close of the NYSE (usually 4:00 p.m. Eastern Time) on any business day on which the NYSE has an unscheduled close or intraday trading halt or other disruption, regardless of the time of such unscheduled close, halt or disruption or whether trading resumes, or (iii) such other time as the Board may from time to time determine. On holidays and other days when the NYSE is closed, the Fund’s NAV is not calculated and the Fund does not accept buy or sell orders. However, the value of the Fund’s assets may still be affected on such days to the extent that the Fund holds foreign securities that trade on days that foreign securities markets are open.

Equity securities are valued primarily on the basis of market quotations reported on stock exchanges and other securities markets around the world. Certain equity securities, debt securities and other assets are valued differently. For instance, short-term investments maturing in 60 days or less are valued primarily using the amortized cost method and those maturing in excess of 60 days are valued at the readily available market price. For a Fund organized as a fund-of-funds, its investments in other funds are valued at their NAVs. Market quotations are obtained from outside pricing services approved and monitored pursuant to a policy approved by the Fund’s Board.

If a market price is not readily available or is deemed not to reflect market value, the security will be valued in good faith based on a determination of the security's fair value pursuant to the Portfolio Pricing Policy approved by the Board. The Portfolio Pricing Policy provides that fair value determinations will be made using the methodology set forth in the Policy and deemed most appropriate under the circumstances and considering all available, relevant factors and indications of value. The Portfolio Pricing Policy provides that fair valuation may be used to price securities that trade on a foreign exchange when a significant event has occurred after the foreign exchange closes but before the time at which the Fund's share price is calculated. In addition, a statistical fair valuation process is applied daily to adjust prices of foreign securities traded on foreign exchanges in time zones different from the United States utilizing the services of a designated pricing vendor. Although the use of statistical fair valuation is intended to and may decrease opportunities for time zone arbitrage transactions, there can be no assurance that it will successfully decrease arbitrage opportunities. Please consult the SAI for more information on the factors to be considered in making fair value determinations; the significant events that may necessitate fair valuation of foreign securities; and the Fund's statistical fair valuation methodology.

Prospectus 2022 41

Columbia Acorn® Fund

Buying, Selling and Exchanging Shares (continued)

When fair valuation is used to price securities, the values for those securities may be higher or lower than values used by another fund to price the security. Also, the use of fair valuation may cause the Fund's performance to diverge to a greater degree from the performance of various benchmarks used to compare the Fund's performance because benchmarks generally do not use fair valuation techniques. Because of the judgment involved in fair valuation decisions, there can be no assurance that the value ascribed to a particular security is accurate.

Transaction Rules and Policies

The Fund, the Distributor or the Transfer Agent may refuse any order to buy or exchange shares. If this happens, the Fund will return any money it received, but no interest will be paid on that money. Your financial intermediary may have rules and policies in place that are in addition to or different than those described below.

Order Processing

Orders to buy, sell or exchange Fund shares are processed on business days. Depending upon the class of shares, orders can be made by mail, by telephone or online. Orders received in “good form” by the Transfer Agent or your financial intermediary before the end of a business day are priced at the NAV per share (plus any applicable sales charge) of the Fund's applicable share class on that day. Orders received after the end of a business day will receive the next business day's NAV per share (plus any applicable sales charge). For Direct-at-Fund Accounts (as defined below), when a written order to buy, sell or exchange shares is sent to the Transfer Agent, the share price used to fill the order is the next price calculated by the Fund after the Transfer Agent receives the transaction request in “good form” at its transaction processing center (i.e., the Fund’s express mail address), not the P.O. Box provided for regular mail delivery. The market value of the Fund's investments may change between the time you submit your order and the time the Fund next calculates its NAV per share. The business day that applies to your order is also called the trade date.

“Good Form”

An order is in “good form” if the Transfer Agent or your financial intermediary has received payment (in the case of purchases) and all of the information and documentation it deems necessary to effect your order. For example, when you sell shares, “good form” means that your request (i) has complete instructions and written requests include the signatures of all account owners, (ii) is for an amount that is less than or equal to the shares in your account for which payment has been received and collected, (iii) has a Medallion Signature Guarantee for amounts greater than $100,000 and certain other transactions, as described below, and (iv) includes any other required documents completed and attached. For the documents required for sales by corporations, agents, fiduciaries, surviving joint owners and other legal entities, call 800.345.6611.

Medallion Signature Guarantees

The Transfer Agent may require a Medallion Signature Guarantee for your signature in order to process certain transactions, including if: (i) the transaction amount is over $100,000; (ii) you want your check made payable to someone other than the registered account owner(s); (iii) the address of record has changed within the last 30 days; (iv) you want the check mailed to an address other than the address of record; (v) you want proceeds to be sent according to existing bank account instructions not coded for outgoing Automated Clearing House (ACH) or wire, or to a bank account not on file; or (vi) you are changing legal ownership of your account.

A Medallion Signature Guarantee helps assure that a signature is genuine and not a forgery. A Medallion Signature Guarantee must be provided by an eligible guarantor institution including, but not limited to, the following: a bank, credit union, savings association, broker or dealer that participates in the Securities Transfer Association Medallion Program (STAMP), the Stock Exchange Medallion Program (SEMP) or the New York Stock Exchange Medallion Signature Program (MSP). For other transactions, the Transfer Agent may require a signature guarantee. Notarization by a notary public is not an acceptable signature guarantee. The Transfer Agent reserves the right to reject a signature guarantee and to request additional documentation for any transaction.

42 Prospectus 2022

Columbia Acorn® Fund

Buying, Selling and Exchanging Shares (continued)

Customer Identification Program

Federal law requires the Fund to obtain and record specific personal information to verify your identity when you open an account. This information may include your name, address, date of birth (for individuals) and taxpayer or other government issued identification (e.g., social security number (SSN) or other taxpayer identification number (TIN)). If you fail to provide the requested information, the Fund may need to delay the date of your purchase or may be unable to open your account, which may result in a return of your investment monies. In addition, if the Fund is unable to verify your identity after your account is open, the Fund reserves the right to close your account or take other steps as deemed reasonable. The Fund will not be liable for any loss resulting from any purchase delay, application rejection or account closure due to a failure to provide proper identifying information.

Small Account Policy — Class A, Class C, and Class Inst Share Accounts Below the Minimum Account Balance

The Funds generally will automatically sell your shares if the value of your Fund account (treating each account of the Fund you own separately from any other account of the Fund you may own) falls below the applicable minimum account balance. Any otherwise applicable CDSC will not be imposed on such an automatic sale of your shares. Generally, you may avoid such an automatic sale by raising your account balance to at least $250 or consolidating your multiple accounts you may have with the Funds through an exchange (so as to maintain at least $250 in each of your accounts). The minimum account balance varies among share classes and types of accounts, as follows:

Minimum Account Balance
	Minimum Account Balance
For all classes and account types except those listed below	$250 (None for accounts with Systematic Investment Plans)
Individual Retirement Accounts for all classes except those listed below	None
Class Adv, Class Inst2, Class Inst3 and Class R	None

For shares held directly with the Funds’ Transfer Agent, if your shares are sold, the Transfer Agent will remit the sale proceeds to you. The Transfer Agent will send you written notification in advance of any automatic sale, which will provide details on how you may avoid such an automatic sale. Generally, you may avoid such an automatic sale by raising your account balance to at least $250, consolidating your multiple accounts you may have with the Funds through an exchange (so as to maintain at least $250 in each of your accounts), or setting up a Systematic Investment Plan. For more information, contact the Transfer Agent or your financial intermediary. The Transfer Agent's contact information (toll-free number and mailing addresses) as well as the Funds’ website address can be found at the beginning of the section Choosing a Share Class.

For shares purchased and held for your benefit through a financial intermediary, the Funds may instruct the intermediary to automatically sell your Fund shares if the transaction can be operationally administered by the intermediary.

Small Account Policy — Class A, Class C, and Class Inst Share Accounts Minimum Balance Fee

If the value of your Fund account (treating each account of the Fund you own separately from any other account of the Fund you may own) falls below the minimum initial investment requirement applicable to you for any reason, including as a result of market decline, your account generally could be subject to a $20 annual fee. The Transfer Agent will reduce the expenses paid by the Fund by any amounts it collects from the assessment of this fee. For Funds that do not have transfer agency expenses against which to offset the amount collected through assessment of this fee, the fee will be paid directly to the Fund. The Funds reserve the right to lower the account size trigger point for the minimum balance fee in any year or for any class of shares when we believe it is appropriate to do so in light of declines in the market value of Fund shares or for other reasons.

For shares held directly with the Funds’ Transfer Agent, this fee will be assessed through the automatic sale of Fund shares in your account. Any otherwise applicable CDSC will not be imposed on such an automatic sale of your shares. The Transfer Agent will send you written notification in advance of assessing any fee, which will provide

Prospectus 2022 43

Columbia Acorn® Fund

Buying, Selling and Exchanging Shares (continued)

details on how you can avoid the imposition of such fee. Generally, you may avoid the imposition of such fee by raising your Fund account balance, consolidating your multiple accounts you may have with the Funds, or setting up a Systematic Investment Plan that invests at least monthly. For more information, contact the Transfer Agent or your financial intermediary. The Transfer Agent's contact information (toll-free number and mailing addresses) as well as the Funds’ website address can be found at the beginning of the section Choosing a Share Class.

For shares purchased and held for your benefit through a financial intermediary, this fee could be assessed through the automatic sale of Fund shares in your account if instructed by the Fund and the transaction can be operationally administered by the intermediary.

Exceptions to the Small Account Policy (Accounts Below Minimum Account Balance) and Minimum Balance Fee

The automatic sale of Fund shares in accounts under $250 and the annual minimum balance fee described above do not apply to shareholders of Class Adv, Class Inst2, Class Inst3 and Class R shares; shareholders holding their shares through financial intermediary networked accounts; wrap fee and omnibus accounts; accounts with active monthly Systematic Investment Plans; certain qualified retirement plans; and health savings accounts. The automatic sale of Fund shares of accounts under the applicable minimum account balance does not apply to individual retirement plans.

Small Account Policy — Financial Intermediary Networked and Wrap Fee Accounts

The Funds may automatically redeem, at any time, financial intermediary networked accounts and wrap fee accounts that have account balances of $20 or less or have less than one share.

For shares purchased and held for your benefit through a financial intermediary, the Funds may instruct the intermediary to automatically sell your Fund shares if the transaction can be operationally administered by the intermediary.

Information Sharing Agreements

As required by Rule 22c-2 under the 1940 Act, the Funds or certain of their service providers will enter into information sharing agreements with financial intermediaries, including participating life insurance companies and financial intermediaries that sponsor or offer retirement plans through which shares of the Funds are made available for purchase. Pursuant to Rule 22c-2, financial intermediaries are required, upon request, to: (i) provide shareholder account and transaction information; and (ii) execute instructions from the Fund to restrict or prohibit further purchases of Fund shares by shareholders who have been identified by the Fund as having engaged in transactions that violate the Fund's excessive trading policies and procedures.

Excessive Trading Practices Policy

Right to Reject or Restrict Share Transaction Orders— The Fund is intended for investors with long-term investment purposes and is not intended as a vehicle for frequent trading activity (market timing) that is excessive. Investors should transact in Fund shares primarily for investment purposes. The Board has adopted excessive trading policies and procedures that are designed to deter excessive trading by investors (the Excessive Trading Policies and Procedures). The Fund discourages and does not accommodate excessive trading.

The Fund reserves the right to reject, without any prior notice, any purchase or exchange order for any reason, and will not be liable for any loss resulting from rejected orders. For example, the Fund may in its sole discretion restrict or reject a purchase or exchange order even if the transaction is not subject to the specific limitation described below if the Fund or its agents determine that accepting the order could interfere with efficient management of the Fund's portfolio or is otherwise contrary to the Fund's best interests. The Excessive Trading Policies and Procedures apply equally to purchase or exchange transactions communicated directly to the Transfer Agent and to those received by financial intermediaries.

Specific Buying and Exchanging Limitations — If the Fund detects that an investor has made two “material round trips” in any 28-day period, it will generally reject the investor's future purchase orders, including exchange purchase orders, involving any Fund.

44 Prospectus 2022

Columbia Acorn® Fund

Buying, Selling and Exchanging Shares (continued)

For these purposes, a “round trip” is a purchase or exchange into the Fund followed by a sale or exchange out of the Fund, or a sale or exchange out of the Fund followed by a purchase or exchange into the Fund. A “material” round trip is one that is deemed by the Fund to be material in terms of its amount or its potential detrimental impact on the Fund. Independent of this limit, the Fund may, in its sole discretion, reject future purchase orders by any person, group or account that appears to have engaged in any type of excessive trading activity.

These limits generally do not apply to automated transactions or transactions by registered investment companies in a “fund-of-funds” structure. These limits do not apply to payroll deduction contributions by retirement plan participants, transactions initiated by a retirement plan sponsor or certain other retirement plan transactions consisting of rollover transactions, loan repayments and disbursements, and required minimum distribution redemptions. They may be modified or rescinded for accounts held by certain retirement plans to conform to plan limits, for considerations relating to the Employee Retirement Income Security Act of 1974 or regulations of the Department of Labor, and for certain asset allocation or wrap programs. Accounts known to be under common ownership or control generally will be counted together, but accounts maintained or managed by a common intermediary generally will not be considered to be under common ownership or control. The Fund reserves the right to modify these restrictions at any time without prior notice to shareholders. In addition, the Fund may, in its sole discretion, reinstate trading privileges that have been revoked under the Fund's Excessive Trading Policies and Procedures.

Limitations on the Ability to Detect and Prevent Excessive Trading Practices — The Fund takes various steps designed to detect and prevent excessive trading, including daily review of available shareholder transaction information. However, the Fund receives buy, sell or exchange orders through financial intermediaries, and cannot always know of or reasonably detect excessive trading that may be facilitated by financial intermediaries or by the use of the omnibus account arrangements they offer. Omnibus account arrangements are common forms of holding shares of mutual funds, particularly among certain financial intermediaries such as broker-dealers, retirement plans and variable insurance products. These arrangements often permit financial intermediaries to aggregate their clients' transactions and accounts, and in these circumstances, the identities of the financial intermediary clients that beneficially own Fund shares are often not known to the Fund.

Some financial intermediaries apply their own restrictions or policies to their clients’ transactions and accounts, which may be more or less restrictive than those described here. This may impact the Fund's ability to curtail excessive trading, even where it is identified. For these and other reasons, it is possible that excessive trading may occur despite the Fund's efforts to detect and prevent it.

Although these restrictions and policies involve judgments that are inherently subjective and may involve some selectivity in their application, the Fund seeks to act in a manner that it believes is consistent with the best interests of Fund shareholders in making any such judgments.

Risks of Excessive Trading — Excessive trading creates certain risks to the Fund's long-term shareholders and may create the following adverse effects:

■ negative impact on the Fund's performance;

■ potential dilution of the value of the Fund's shares;

■ interference with the efficient management of the Fund's portfolio, such as the need to maintain undesirably large cash positions, the need to use its line of credit or the need to buy or sell securities it otherwise would not have bought or sold;

■ losses on the sale of investments resulting from the need to sell securities at less favorable prices;

■ increased taxable gains to the Fund's remaining shareholders resulting from the need to sell securities to meet sell orders; and

■ increased brokerage and administrative costs.

To the extent that the Fund invests significantly in foreign securities traded on markets that close before the Fund's valuation time, it may be particularly susceptible to dilution as a result of excessive trading. Because events may occur after the close of foreign markets and before the Fund's valuation time that influence the value of foreign

Prospectus 2022 45

Columbia Acorn® Fund

Buying, Selling and Exchanging Shares (continued)

securities, investors may seek to trade Fund shares in an effort to benefit from their understanding of the value of foreign securities as of the Fund's valuation time. This is often referred to as price arbitrage. The Fund has adopted procedures designed to adjust closing market prices of foreign securities under certain circumstances to reflect what the Fund believes to be the fair value of those securities as of its valuation time. To the extent the adjustments do not work fully, investors engaging in price arbitrage may cause dilution in the value of the Fund's shares held by other shareholders.

The Columbia Acorn Funds may invest in thinly traded equity securities of small-capitalization companies. Because

these securities are often traded infrequently, investors may seek to trade Fund shares in an effort to benefit from their understanding of the value of these securities as of the Fund's valuation time. This is also a type of price arbitrage. Any such frequent trading strategies may interfere with efficient management of the Fund's portfolio to a greater degree than would be the case for mutual funds that invest only, or significantly, in highly liquid securities, in part because the Fund may have difficulty selling these particular investments at advantageous times or prices to satisfy large and/or frequent sell orders. Any successful price arbitrage may also cause dilution in the value of Fund shares held by non-redeeming shareholders.

Opening an Account and Placing Orders

We encourage you to consult with a financial advisor who can help you with your investment decisions and who can help you open an account. Once you have an account, you can buy, sell or exchange shares by contacting your financial advisor who will send your order to the Transfer Agent or your financial intermediary. As described below, once you have an account you can also communicate your orders directly to the Transfer Agent by mail, by telephone or online.

The Funds are generally available directly and through broker-dealers, banks and other financial intermediaries or institutions, and through certain qualified and non-qualified plans, wrap fee products or other investment products sponsored by financial intermediaries. You may buy, sell, or exchange shares through your financial intermediary. If you maintain your account directly with your financial intermediary, you must contact that agent to process your transaction.

Not all financial intermediaries offer the Funds (or all classes of Fund shares) and certain financial intermediaries that offer the Funds may not offer all Funds on all investment platforms or programs. Please consult with your financial intermediary to determine the availability of the Funds. If you set up an account at a financial intermediary that does not have, and is unable to obtain, a selling agreement with the Distributor, you will not be able to transfer Fund holdings to that account. In that event, you must either maintain your Fund holdings with your current financial intermediary or find another financial intermediary with a selling agreement.

Financial intermediaries that offer the Funds may charge you additional fees for the services they provide and they may have different policies that are not described in this prospectus. An investor transacting in a class of Fund shares without any front-end sales charge, CDSC, or other asset-based fee for sales or distribution, such as a Rule 12b-1 fee, may be required to pay a commission to the financial intermediary for effecting such transactions. The Funds are offered in a number of different share classes that have different fees and expenses and other features. Some differences in the policies of different financial intermediaries may include different minimum investment amounts, exchange privileges, Fund/class choices and cutoff times for investments. Additionally, recordkeeping, transaction processing and payments of distributions relating to your account may be performed by the financial intermediaries through which your shares of the Fund are held. Since the Fund (and its service providers) may not have a record of your account transactions, you should always contact the financial intermediary through which you purchased or at which you maintain your shares of the Fund to make changes to your account, to give instructions concerning your account, or to obtain information about your account. The Fund and its service providers, including the Distributor and the Transfer Agent, are not responsible for the failure of any financial intermediary to carry out its obligations to its customers.

The Fund may engage financial intermediaries to receive purchase, exchange and sell orders on its behalf. Accounts established directly with the Fund will be serviced by the Transfer Agent. The Funds, the Transfer Agent and the Distributor do not provide investment advice.

46 Prospectus 2022

Columbia Acorn® Fund

Buying, Selling and Exchanging Shares (continued)

Direct-At-Fund Accounts (Accounts Held Directly with the Fund)

Fund shares can be held in a variety of ways. You can hold Fund shares through an account established and held through the financial intermediary through which you purchased Fund shares, or you or your financial intermediary can establish an account directly with the Fund, in which case you will receive Fund account transaction confirmations and statements from the Transfer Agent, and not your financial intermediary (Direct-at-Fund Accounts). Direct-at-Fund Accounts include accounts held at the Transfer Agent that do not or no longer have a financial intermediary assigned to them.

To open a Direct-at-Fund Account, complete a Fund account application with your financial advisor or investment professional, and mail the account application to the Transfer Agent. Account applications may be obtained at columbiathreadneedleus.com or may be requested by calling 800.345.6611. Make your check payable to the Fund. You will be assessed a $15 fee for any checks rejected by your financial institution due to insufficient funds or other reasons. The Funds do not accept cash, credit card convenience checks, money orders, traveler's checks, starter checks, third or fourth party checks, or other cash equivalents.

Mail your check and completed application to the Transfer Agent at its regular or express mail address that can be found at the beginning of the section Choosing a Share Class. You may also use these addresses to request an exchange or redemption of Fund shares. When a written order to buy, sell or exchange shares is sent to the Transfer Agent, the share price used to fill the order is the next price calculated by the Fund after the Transfer Agent receives your transaction request in “good form” at its transaction processing center (i.e., the Fund’s express mail address), not the P.O. Box provided for regular mail delivery.

You will be sent a statement confirming your purchase and any subsequent transactions in your account. You will also be sent quarterly and annual statements detailing your transactions in the Fund and the other Funds you own under the same account. Duplicate quarterly account statements for the current year and duplicate annual statements for the most recent prior calendar year will be sent to you free of charge. Copies of year-end statements for prior years are available for a fee. Please contact the Transfer Agent for more information.

Written Transactions – Direct-at-Fund Accounts

If you have a Direct-at-Fund Account, you can communicate written buy, sell or exchange orders to the Transfer Agent at its address that can be found at the beginning of the section Choosing a Share Class. When a written order to buy, sell or exchange shares is sent to the Transfer Agent, the share price used to fill the order is the next price calculated by the Fund after the Transfer Agent receives your transaction request in “good form” at its transaction processing center (i.e., the Fund’s express mail address), not the P.O. Box provided for regular mail delivery.

Include in your transaction request letter: your name; the name of the Fund(s); your account number; the class of shares to be purchased, exchanged or sold; your SSN or other TIN; the dollar amount or number of shares you want to purchase, exchange or sell; specific instructions regarding delivery of any redemption proceeds or exchange destination (i.e., the Fund/class to be exchanged into); signature(s) of all registered account owner(s); and any special documents the Transfer Agent may require in order to process your order.

Corporate, trust or partnership accounts may need to send additional documents. Payment will be mailed to the address of record and made payable to the names listed on the account, unless your request specifies differently and is signed by all owners.

Telephone Transactions – Direct-at-Fund Accounts

For Class A, Class C, Class Inst, Class Inst3 and Class R shares, if you have a Direct-at-Fund Account, you may place orders to buy, sell or exchange shares by telephone through the Transfer Agent. To place orders by telephone, call 800.422.3737. Have your account number and SSN or TIN available when calling.

You can sell Fund shares via telephone and receive redemption proceeds: by electronic funds transfer via ACH, by wire, or by check to the address of record, subject to a maximum of $100,000 of shares per day, per Fund account. You can buy Fund shares via telephone by electronic funds transfer via ACH from your bank account up to a maximum

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of $100,000 of shares per day, per Fund account, or by wire from your bank account without a maximum. See below for more information regarding wire and electronic fund transfer transactions. Certain restrictions apply, so please call the Transfer Agent at 800.422.3737 for this and other information in advance of any need to transact via telephone.

Telephone orders may not be as secure as written orders. The Fund will take reasonable steps to confirm that telephone instructions are genuine. For example, we require proof of your identification before we will act on instructions received by telephone and may record telephone conversations. However, the Fund and its agents will not be responsible for any losses, costs or expenses resulting from an unauthorized telephone instruction when reasonable steps have been taken to confirm that telephone instructions are genuine. Telephone orders may be difficult to complete during periods of significant economic or market change or business interruption.

Online Transactions – Direct-at-Fund Accounts

For Class A, Class C, Class Inst, Class Inst3 and Class R shares, if you have a Direct-at-Fund Account, you may be able to place orders to buy, sell, or exchange shares online. Contact the Transfer Agent at 800.345.6611 for more information on certain account trading restrictions and the special sign-up procedures required for online transactions. You can also go to columbiathreadneedleus.com/investor/ to sign up for online transactions. The Transfer Agent has procedures in place to authenticate electronic orders you send through the internet. You will be required to accept the terms of an online agreement and to establish an online account and utilize a password in order to access online account services. You can sell a maximum of $100,000 of shares per day, per Fund account through your online account if you qualify for internet orders. Wire transactions are not permitted online.

Wire Transactions – Direct-at-Fund Accounts

If you hold a Direct-at-Fund Account, you may purchase or redeem Class A, Class C, Class Inst, Class Inst3 and Class R shares of a Fund by wiring money from (or to) your bank account to (or from) your Fund account. You must set up this feature prior to your request unless you are submitting your request in writing, which may require a Medallion Signature Guarantee. Please contact the Transfer Agent by calling 800.422.3737 to obtain the necessary forms and requirements. The Transfer Agent charges a fee for shares sold by wire. The Transfer Agent may waive the fee for certain accounts. In the case of a redemption, the receiving bank may charge an additional fee. The minimum amount that can be redeemed by wire is $500. When selling Fund shares via a telephone request, the maximum amount that can be redeemed via wire transfer is $100,000 per day, per Fund account. Wire transactions are not permitted online.

Electronic Funds Transfer via ACH – Direct-at-Fund Accounts

If you hold a Direct-at-Fund Account, you may purchase or redeem Class A, Class C, Class Inst, Class Inst3 and Class R shares of a Fund by electronically transferring money via Automated Clearing House (ACH) from (or to) your bank account to (or from) your Fund account subject to a maximum of $100,000 of shares per day, per Fund account. You must set up this feature prior to your request, unless you are submitting your request in writing, which may require a Medallion Signature Guarantee. Please contact the Transfer Agent by calling 800.422.3737 to obtain the necessary forms and requirements. Your bank may take up to three business days to post an electronic funds transfer to (or from) your Fund account.

Buying Shares

Eligible Investors

Class A Shares

Class A shares are available to the general public for investment.

Class Adv Shares

Class Adv shares are available only to (i) omnibus retirement plans, including self-directed brokerage accounts within omnibus retirement plans that clear through institutional no transaction fee (NTF) platforms, (ii) trust companies or similar institutions, (iii) broker-dealers, banks, trust companies and similar institutions that clear Fund share

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transactions for their client or customer investment advisory or similar accounts through designated financial intermediaries and their mutual fund trading platforms that have been granted specific written authorization from the Transfer Agent with respect to Class Adv eligibility apart from selling, servicing or similar agreements, (iv) 501(c)(3) charitable organizations, (v) 529 plans, (vi) health savings accounts, (vii) investors participating in a fee-based advisory program sponsored by a financial intermediary or other entity that is not compensated by the Fund for those services, other than payments for shareholder servicing or sub-accounting performed in place of the Transfer Agent, and (viii) commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Adv shares within such platform.

Class C Shares

Class C shares are available to the general public for investment, except that Direct-at-Fund Accounts that do not have a financial intermediary assigned to them are not permitted to purchase Class C shares; Class C share purchase orders received on or after such date from Direct-at-Fund Accounts that do not have a financial intermediary assigned to the account will automatically be invested in Class A shares of the same Fund.

Class Inst Shares

Class Inst shares are available only to the categories of eligible investors described below under Class Inst Shares Minimum Initial Investments. Financial intermediaries that clear Fund share transactions through designated financial intermediaries and their mutual fund trading platforms that were given specific written notice from the Transfer Agent of the termination, effective March 29, 2013, of their eligibility for new purchases of Class Inst shares and omnibus retirement plans are not permitted to establish new Class Inst accounts, subject to certain exceptions described below.

Omnibus retirement plans that opened and, subject to certain exceptions, funded a Class Inst account with the Fund as of the close of business on March 28, 2013 and have continuously held Class Inst shares in such account after such date (each, a grandfathered plan), may generally continue to make additional purchases of Class Inst shares, open new Class Inst accounts and add new participants. In addition, an omnibus retirement plan affiliated with a grandfathered plan may, in the sole discretion of the Distributor, open new Class Inst accounts in a Fund if the affiliated plan opened a Class Inst account on or before March 28, 2013. If an omnibus retirement plan invested in Class Inst shares changes recordkeepers after March 28, 2013, any new accounts established for that plan may not be established in Class Inst shares, but such a plan may establish new accounts in a different share class for which the plan is eligible.

Accounts of financial intermediaries (other than omnibus retirement plans, which are discussed above) that clear Fund share transactions for their client or customer accounts through designated financial intermediaries and their mutual fund trading platforms that received specific written notice from the Transfer Agent of the termination, effective March 29, 2013, of their eligibility for new purchases of Class Inst shares will not be permitted to establish new Class Inst accounts or make additional purchases of Class Inst shares (other than through reinvestment of distributions). Any such account may, at its holder’s option, exchange Class Inst shares of a Fund, without the payment of a sales charge, for Class A shares of the same Fund.

Class Inst2 Shares

Class Inst2 shares are available only to (i) certain registered investment advisers and family offices that clear Fund share transactions for their client or customer accounts through designated financial intermediaries and their mutual fund trading platforms that have been granted specific written authorization from the Transfer Agent with respect to Class Inst2 eligibility apart from selling, servicing or similar agreements; (ii) omnibus retirement plans; (iii) health savings accounts, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst2 shares within such platform and that Fund shares are held in an omnibus account; and (iv) institutional investors that are clients of the Columbia Threadneedle Global Institutional Distribution Team that invest in Class Inst2 shares for their own account through platforms approved by the Distributor or an affiliate thereof to offer and/or service Class Inst2 shares within such platform. Prior to November 8, 2012, Class Inst2

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shares were closed to new investors and new accounts, subject to certain exceptions. Existing shareholders who do not satisfy the new eligibility requirements for investment in Class Inst2 may not establish new Class Inst2 accounts but may continue to make additional purchases of Class Inst2 shares in accounts opened and funded prior to November 8, 2012; provided, however, that investment advisory programs and similar programs that opened a Class Inst2 account as of May 1, 2010, and continuously hold Class Inst2 shares in such account after such date, may generally not only continue to make additional purchases of Class Inst2 shares but also open new Class Inst2 accounts for such pre-existing programs and add new shareholders in the program.

Class Inst3 Shares

Class Inst3 shares are available to: (i) group retirement plans that maintain plan-level or omnibus accounts with the Fund (through the Transfer Agent); (ii) institutional investors that are clients of the Columbia Threadneedle Global Institutional Distribution Team that invest in Class Inst3 shares for their own account through platforms approved by the Distributor or an affiliate thereof to offer and/or service Class Inst3 shares within such platform; (iii) collective trust funds; (iv) affiliated or unaffiliated mutual funds (e.g., funds operating as funds-of-funds); (v) fee-based platforms of financial intermediaries (or the clearing intermediary that they trade through) that have an agreement with the Distributor or an affiliate thereof that specifically authorizes the financial intermediary to offer and/or service Class Inst3 shares within such platform, provided also that Fund shares are held in an omnibus account; (vi) commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst3 shares within such platform and that Fund shares are held in an omnibus account; (vii) health savings accounts, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst3 shares within such platform and that Fund shares are held in an omnibus account; and (viii) bank trust departments, subject to an agreement with the Distributor that specifically authorizes offering Class Inst3 shares and provided that Fund shares are held in an omnibus account. In each case above where noted that Fund shares are required to be held in an omnibus account, the Distributor may, in its discretion, determine to waive this requirement.

Class R Shares

Class R shares are available only to eligible health savings accounts sponsored by third party platforms, including those sponsored by Ameriprise Financial affiliates, eligible retirement plans and, in the sole discretion of the Distributor, other types of retirement accounts held through platforms maintained by financial intermediaries approved by the Distributor. Eligible retirement plans include any retirement plan other than individual 403(b) plans. Class R shares are generally not available for investment through retail nonretirement accounts, traditional and Roth IRAs, Coverdell Education Savings Accounts, SEPs, SAR-SEPs, Simple IRAs or 529 tuition programs. Contact the Transfer Agent or your retirement plan or health savings account administrator for more information about investing in Class R shares.

Additional Eligible Investors

In addition, the Distributor, in its sole discretion, may accept investments in any share class from investors other than those listed in this prospectus, and may also waive certain eligibility requirements for operational and other reasons, including but not limited to any requirement to maintain Fund shares in networked or omnibus accounts.

Minimum Initial Investments

The table below shows the Fund’s minimum initial investment requirements, which may vary by class and type of account.

The Fund reserves the right to redeem your shares if your account falls below the Fund’s minimum initial investment requirement.

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Minimum Initial Investments
	Minimum Initial Investment(a)	Minimum Initial Investment for Accounts with Systematic Investment Plans
For all classes and account types except those listed below	$2,000	$100
Individual Retirement Accounts for all classes except those listed below	$1,000	$100
Group retirement plans	None	N/A
Class Adv and Class Inst	$0, $1,000 or $2,000(b)	$100(b)
Class Inst2 and Class R	None	N/A
Class Inst3	$0, $1,000, $2,000 or $1 million(c)	$100(c)

(a) If your Class A, Class Adv, Class C, Class Inst, or Class Inst3 shares account balance falls below the minimum initial investment amount for any reason, including a market decline, you may be asked to increase it to the minimum initial investment amount or establish a monthly Systematic Investment Plan. If you do not do so, your account will be subject to a $20 annual low balance fee and/or shares may be automatically redeemed and the proceeds mailed to you if the account falls below the minimum account balance. See Buying, Selling and Exchanging Shares — Transaction Rules and Policies above. There is no minimum initial investment in Class A shares for accounts held in an omnibus account on a mutual fund only platform offered through your financial intermediary.

(b) The minimum initial investment in Class Adv shares is $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts) for commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customers, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Adv shares within such platform; for all other eligible Class Adv share investors (see Buying Shares – Eligible Investors – Class Adv Shares above), there is no minimum initial investment. The minimum initial investment amount for Class Inst shares is $0, $1,000 or $2,000 depending upon the category of eligible investor. See — Class Inst Shares Minimum Initial Investments below. The minimum initial investment amount for Systematic Investment Plan accounts is the same as the amount set forth in the first two rows of the table, as applicable.

(c) There is no minimum initial investment in Class Inst3 shares for: group retirement plans that maintain plan-level or omnibus accounts with the Fund; collective trust funds; affiliated or unaffiliated mutual funds (e.g., funds operating as funds-of-funds); and fee -based platforms of financial intermediaries (or the clearing intermediary that they trade through) that have an agreement with the Distributor or an affiliate thereof that specifically authorizes the financial intermediary to offer and/or service Class Inst3 shares within such platform and Fund shares are held in an omnibus account. The minimum initial investment in Class Inst3 shares is $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts) for commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst3 shares within such platform and Fund shares are held in an omnibus account. The minimum initial investment in Class Inst3 shares is $1 million, unless waived in the discretion of the Distributor, for the following investors: institutional investors that are clients of the Columbia Threadneedle Global Institutional Distribution Team that invest in Class Inst3 shares for their own account through platforms approved by the Distributor or an affiliate thereof to offer and/or service Class Inst3 shares within such platform; and bank trust departments, subject to an agreement with the Distributor that specifically authorizes offering Class Inst3 shares and provided that Fund shares are held in an omnibus account. The Distributor may, in its discretion, waive the $1 million minimum initial investment required for these Class Inst3 investors. In each case above where noted that Fund shares are required to be held in an omnibus account, the Distributor, may, in its discretion, determine to waive this requirement.

Additional Information about Minimum Initial Investments

The minimum initial investment requirements may be waived for accounts that are managed by an investment professional, or for accounts held in approved discretionary or non-discretionary wrap programs. The Distributor, in its sole discretion, may also waive minimum initial investment requirements for other account types.

Minimum investment and related requirements may be modified at any time, with or without prior notice. If your account is closed and then re-opened with a Systematic Investment Plan, your account must meet the then-current applicable minimum initial investment.

Class Inst Shares Minimum Initial Investments

There is no minimum initial investment in Class Inst shares for the following categories of eligible investors:

■ Any health savings account sponsored by a third party platform.

■ Any investor participating in an account sponsored by a financial intermediary or other entity (that provides services to the account) that is paid a fee-based advisory fee by the investor and that is not compensated by the Fund for those services, other than payments for shareholder servicing or sub-accounting performed in place of the Transfer Agent.

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■ Any commissionable brokerage account, if a financial intermediary has received a written approval from the Distributor to waive the minimum initial investment in Class Inst shares.

■ Any Trustee (or family member) of Columbia Acorn Trust.

■ Any employee (or family member) of the Investment Manager.

The minimum initial investment in Class Inst shares for the following categories of eligible investors is $1,000:

■ Individual retirement accounts (IRAs) on commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst shares within such platform.

■ Any current employee of Columbia Management Investment Advisers LLC, the Distributor or the Transfer Agent and immediate family members of any of the foregoing who share the same address are eligible to invest in Class Inst shares through an individual retirement account (IRA). If you maintain your account with a financial intermediary, you must contact that financial intermediary each time you seek to purchase shares to notify them that you qualify for Class Inst shares. If Class Inst shares are not available at your financial intermediary, you may consider opening a Direct-at-Fund Account. It is your obligation to advise your financial intermediary or (in the case of Direct-at-Fund Accounts) the Transfer Agent that you qualify for Class Inst shares; be prepared to provide proof thereof.

The minimum initial investment in Class Inst shares for the following categories of eligible investors is $2,000:

■ Investors (except investors in individual retirement accounts (IRAs)) who purchase Fund shares through commissionable brokerage platforms where the financial intermediary holds the shares in an omnibus account and, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst shares within such platform.

■ Any current employee of Columbia Management Investment Advisers LLC, the Distributor or the Transfer Agent and immediate family members of any of the foregoing who share the same address are eligible to invest in Class Inst shares (other than individual retirement accounts (IRAs), for which the minimum initial investment is $1,000). If you maintain your account with a financial intermediary, you must contact that financial intermediary each time you seek to purchase shares to notify them that you qualify for Class Inst shares. If Class Inst shares are not available at your financial intermediary, you may consider opening a Direct-at-Fund Account. It is your obligation to advise your financial intermediary or (in the case of Direct-at-Fund Accounts) the Transfer Agent that you qualify for Class Inst shares; be prepared to provide proof thereof.

■ Certain financial institutions and intermediaries, such as insurance companies, trust companies, banks, endowments, investment companies or foundations, buying shares for their own account, including Ameriprise Financial and its affiliates and/or subsidiaries.

■ Bank trust departments that assess their clients an asset-based fee.

■ Any trustee or director (or family member of a trustee or director) of a fund distributed by the Distributor (other than the Columbia Acorn Funds).

■ Certain other investors as set forth in more detail in the SAI.

Systematic Investment Plan

The Systematic Investment Plan allows you to schedule regular purchases via automatic transfers from your bank account to the Fund on a monthly, quarterly or semiannual basis. Contact the Transfer Agent or your financial intermediary to set up the plan. Systematic Investment Plans may not be available for all share classes. With the exception of Columbia Government Money Market Fund, Systematic Investment Plan purchases will be confirmed on your quarterly account statement. Columbia Government Money Market Fund Systematic Investment Plan purchases will be confirmed at the time of the purchase. If establishing a Systematic Investment Plan to reduce the initial fund minimum, the plan needs to be established monthly to avoid the small account fee.

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Dividend Diversification

Generally, you may automatically invest Fund distributions into the same class of shares (and in some cases certain other classes of shares) of another Fund without paying any applicable front-end sales charge. Call the Transfer Agent at 800.345.6611 for details. The ability to invest distributions from one Fund to another Fund may not be available to accounts held at all financial intermediaries.

Other Purchase Rules You Should Know

■ Once the Transfer Agent or your financial intermediary receives your purchase order in “good form,” your purchase will be made at the Fund’s next calculated public offering price per share, which is the NAV per share plus any sales charge that applies (i.e., the trade date).

■ Once the Fund receives your purchase request in “good form,” you cannot cancel it after the market closes.

■ You generally buy Class A shares at the public offering price per share because purchases of these share classes are generally subject to a front-end sales charge.

■ You buy Class Adv, Class C, Class Inst, Class Inst2, Class Inst3 and Class R shares at NAV per share because no front-end sales charge applies to purchases of these share classes.

■ The Distributor and the Transfer Agent reserve the right to cancel your order request if the Fund does not receive payment within two business days of receiving your purchase order request. The Fund will return any payment received for orders that have been cancelled, but no interest will be paid on that money.

■ Financial intermediaries are responsible for sending your purchase orders to the Transfer Agent and ensuring that the Fund receives your money on time.

■ Shares purchased are recorded on the books of the Fund. The Fund does not issue certificates.

■ You generally may make a purchase only into a Fund that is accepting investments.

Please also read Appendix A and contact your financial intermediary for more information regarding any reductions and/or waivers described therein.

Selling Shares

When you sell shares, the amount you receive may be more or less than the amount you invested. Your sale price will be the next NAV calculated after your request is received in “good form,” (i.e., the trade date) minus any applicable CDSC.

Systematic Withdrawal Plan

The Systematic Withdrawal Plan allows you to schedule regular redemptions from your account any business day on a monthly, quarterly or semiannual basis. Currently, Systematic Withdrawal Plans are generally available for Class A, Class Adv, Class C, Class Inst, Class Inst2, and Class Inst3 share accounts. Contact the Transfer Agent or your financial intermediary to set up the plan. To set up the plan, your account balance must meet the class minimum initial investment amount. A Systematic Withdrawal Plan cannot be set up on an account that already has a Systematic Investment Plan established. Note that a Medallion Signature Guarantee may be required if this service is established after your Fund account is opened.

You can choose to receive your withdrawals via check or direct deposit into your bank account. The Fund will deduct any applicable CDSC from the withdrawals before sending redemption proceeds to you. You can cancel the plan by giving the Fund 30 days’ notice in writing or by calling the Transfer Agent at 800.422.3737. It’s important to remember that if you withdraw more than your investment in the Fund is earning, you'll eventually withdraw your entire investment.

Satisfying Fund Redemption Requests

When you sell your Fund shares, the Fund is effectively buying them back from you. This is called a redemption. Except as noted below with respect to newly purchased shares, the Fund typically expects to send you payment for your shares within two business days after your trade date. The Fund can suspend redemptions and/or delay

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payment of redemption proceeds for up to seven days. The Fund can also suspend redemptions and/or delay payment of redemption proceeds in excess of seven days under certain circumstances, including when the NYSE is closed or trading thereon is restricted or during emergency or other circumstances, including as determined by the SEC.

The Fund typically seeks to satisfy redemption requests from cash or cash equivalents held by the Fund, from the proceeds of orders to purchase Fund shares or from the proceeds of sales of Fund holdings effected in the normal course of managing the Fund. However, the Fund may have to sell Fund holdings, including in down markets, to meet heavier than usual redemption requests. For example, under stressed or abnormal market conditions or circumstances, including circumstances adversely affecting the liquidity of the Fund’s investments, the Fund may be more likely to be forced to sell Fund holdings to meet redemptions than under normal market circumstances. In these situations, the Fund’s portfolio managers may have to sell Fund holdings that would not otherwise be sold because, among other reasons, the current price to be received is less than the value of the holdings perceived by the Fund’s portfolio managers. The Fund may also, under certain circumstances (likely under stressed or abnormal market conditions or circumstances), borrow money under a credit facility to which the Fund and certain other Columbia Funds are parties. The Fund and the other Columbia Funds are limited as to the amount that each may individually and collectively borrow under the credit facility. As a result, borrowings available to the Fund under the credit facility might be insufficient, alone or in combination with the other strategies described herein, to satisfy Fund redemption requests. Please see About Fund Investments – Borrowings in the SAI for more information about the credit facility. The Fund is also limited in the total amount it may borrow. Please see About Fund Investments – Fundamental and Non-Fundamental Investment Policies in the SAI for more information about borrowing.

In addition, the Fund reserves the right to honor redemption orders in whole or in part with in-kind distributions of Fund portfolio securities instead of cash. Such in-kind distributions typically represent a pro-rata portion of Fund portfolio assets subject to adjustments (e.g., for non-transferable securities, round lots, and derivatives, if any). In the event the Fund distributes portfolio securities in kind, you may incur brokerage and other transaction costs associated with converting the portfolio securities you receive into cash. Also, the portfolio securities you receive may increase or decrease in value after they are distributed but before you convert them into cash. For U.S. federal income tax purposes, redemptions paid in securities are generally treated the same as redemptions paid in cash. The Trust has elected to be governed by Rule 18f-1 under the 1940 Act, which means that for each redeeming shareholder, the first $250,000, or 1% of the Fund's net asset value, whichever is less, will be paid in cash or cash equivalents and the remainder may be paid in kind.

While the Fund is not required (and may refuse in its discretion) to pay a redemption with an in-kind distribution of Fund portfolio securities and reserves the right to pay the redemption proceeds in cash, if you wish to request an in-kind redemption, please call the Transfer Agent at 800.345.6611. As a result of the operational steps needed to coordinate with the redeeming shareholder’s custodian, in-kind redemptions typically take several weeks to complete after a redemption request is received. The Fund and the redeeming shareholder will typically agree upon a redemption date. Since the Fund’s NAV may fluctuate during this time, the Fund’s NAV may be lower on the agreed-upon redemption date than on an earlier date on which the investment could have been redeemed for cash.

Redemption of Newly Purchased Shares

You may not redeem shares for which the Fund has not yet received payment. Shares purchased by check or electronically by ACH when the purchase payment is not guaranteed will be considered in “good form” for redemption only after they have been held in your account for 6 calendar days after the trade date of the purchase (Collected Shares). If you request a redemption for an amount that, based on the NAV next calculated after your redemption request is received, includes any shares that are not yet Collected Shares, the Fund will only process the redemption up to the amount of the value of Collected Shares available in your account. You must submit a new redemption request if you wish to redeem those shares that were not yet Collected Shares at the time the original redemption request was received by the Fund.

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Other Redemption Rules You Should Know

■ Once the Transfer Agent or your financial intermediary receives your redemption order in “good form,” your shares will be sold at the Fund’s next calculated NAV per share (i.e., the trade date). Any applicable CDSC will be deducted from the amount you're selling and the balance will be remitted to you.

■ Once the Fund receives your redemption request in “good form,” you cannot cancel it after the market closes.

■ The Distributor, in its sole discretion, reserves the right to liquidate Fund shares (of any class of the Fund) held in an omnibus account of a financial intermediary that clears Fund share transactions through a clearing intermediary or platform that charges certain maintenance fees to the Fund if the value of the omnibus account, at the Fund share class (i.e., CUSIP) level, falls below $100,000 (a CUSIP Liquidation Event). The Distributor will provide at least 90 days’ notice of a CUSIP Liquidation Event to financial intermediaries with impacted omnibus accounts. Shareholders invested in the Fund through such omnibus accounts can request through their financial intermediary a tax-free exchange to Class A shares or shareholders can consider holding their Fund shares in a Direct-at-Fund Account, provided requirements to transfer the account are fulfilled. You should discuss your options with your financial intermediary.

■ If you sell your shares that are held in a Direct-at-Fund Account, we will normally send the redemption proceeds by mail or electronically transfer them to your bank account the next business day after the trade date. Note that your bank may take up to three business days to post an electronic funds transfer from your account.

■ If you sell your shares through a financial intermediary, the Funds will normally send the redemption proceeds to your financial intermediary within two business days after the trade date.

■ No interest will be paid on uncashed redemption checks.

■ Other restrictions may apply to retirement accounts. For information about these restrictions, contact your retirement plan administrator.

■ For broker-dealer and wrap fee accounts: The Fund reserves the right to redeem your shares if your account falls below the Fund's minimum initial investment requirement. The Fund will notify your broker-dealer prior to redeeming shares, and will provide details on how to avoid such redemption.

■ Also keep in mind the Funds' Small Account Policy, which is described above in Buying, Selling and Exchanging Shares — Transaction Rules and Policies.

Exchanging Shares

You can generally sell shares of your Fund to buy shares of another Fund (subject to eligibility requirements), in what is called an exchange. You should read the prospectus of, and make sure you understand the investment objective, principal investment strategies, risks, fees and expenses of, the Fund into which you are exchanging. Although the Funds allow certain exchanges from one share class to another share class with higher expenses, you should consider the expenses of each class before making such an exchange. Please see Same-Fund Exchange Privilege below for more information.

You will be subject to a sales charge if, in a Direct-at-Fund Account, you exchange shares that have not previously paid a sales charge, including from Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia U.S. Treasury Index Fund or any other Columbia Fund that does not charge a front-end sales charge, into a Columbia Fund that does assess a sales charge. If you hold your Fund shares through certain financial intermediaries, you may have limited exchangeability among the Funds. Please contact your financial intermediary for more information.

Systematic Exchanges

You may buy Class A, Class C, Class Inst and Class Inst3 shares of a Fund by exchanging each month from another Fund for shares of the same class of the Fund at no additional cost, subject to the following exchange amount minimums: $50 each month for individual retirement accounts (i.e., tax qualified accounts); and $100 each month for non-retirement accounts. Contact the Transfer Agent or your financial intermediary to set up the plan.

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Exchanges will continue as long as your balance in the Fund you are exchanging shares from is sufficient to complete the systematic monthly exchange, subject to the Funds' Small Account Policy described above in Buying, Selling and Exchanging Shares — Transaction Rules and Policies. You may terminate the program or change the amount you would like to exchange (subject to the $50 and $100 minimum requirements noted immediately above) by calling the Transfer Agent at 800.345.6611.

Other Exchange Rules You Should Know

■ Exchanges are made at the NAV next calculated (plus any applicable sales charge) after your exchange order is received in “good form” (i.e., the trade date).

■ Once the Fund receives your exchange request in “good form,” you cannot cancel it after the market closes.

■ The rules for buying shares of a Fund generally apply to exchanges into that Fund, including, if your exchange creates a new Fund account, it must satisfy the minimum investment amount, unless a waiver applies.

■ Shares of the purchased Fund may not be used on the same day for another exchange or sale.

■ If you exchange shares from Class A shares of Columbia Government Money Market Fund to a non-money market Fund, any further exchanges must be between shares of the same class. For example, if you exchange from Class A shares of Columbia Government Money Market Fund into Class C shares of a non-money market Fund, you may not exchange from Class C shares of that non-money market Fund back to Class A shares of Columbia Government Money Market Fund or Class A shares of any other Fund.

■ A sales charge may apply when you exchange shares of a Fund that were not assessed a sales charge at the time you purchased such shares. If you invest through a Direct-at-Fund Account in Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund, Columbia U.S. Treasury Index Fund or any other Columbia Fund that does not impose a front-end sales charge and then you exchange into a Fund that does assess a sales charge, your transaction is subject to a front-end sales charge if you exchange into Class A shares and to a CDSC if you exchange into Class C shares of the Columbia Funds.

■ If you purchased Class A shares of a Columbia Fund that imposes a front-end sales charge (and you paid any applicable sales charge) and you then exchange those shares into Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund, Columbia U.S. Treasury Index Fund or any other Columbia Fund that does not impose a front-end sales charge, you may exchange that amount to Class A of another Fund in the future, including dividends earned on that amount, without paying a sales charge.

■ If your shares are subject to a CDSC, you will not be charged a CDSC upon the exchange of those shares. Any CDSC will be deducted when you sell the shares you received from the exchange. The CDSC imposed at that time will be based on the period that begins when you bought shares of the original Fund and ends when you sell the shares of the Fund you received from the exchange. Any applicable CDSC charged will be the CDSC of the original Fund.

■ You may make exchanges only into a Fund that is legally offered and sold in your state of residence. Contact the Transfer Agent or your financial intermediary for more information.

■ You generally may make an exchange only into a Fund that is accepting investments.

■ The Fund may change or cancel your right to make an exchange by giving the amount of notice required by regulatory authorities (generally 60 days for a material change or cancellation).

■ Unless your account is part of a tax-advantaged arrangement, an exchange for shares of another Fund is a taxable event, and you may recognize a gain or loss for tax purposes.

■ Changing your investment to a different Fund will be treated as a sale and purchase, and you will be subject to applicable taxes on the sale and sales charges on the purchase of the new Fund.

56 Prospectus 2022

Columbia Acorn® Fund

Buying, Selling and Exchanging Shares (continued)

■ Class Inst shares of a Fund may be exchanged for Class A or Class Inst shares of another Fund. In certain circumstances, the front-end sales charge applicable to Class A shares may be waived on exchanges of Class Inst shares for Class A shares. See Buying, Selling and Exchanging Shares — Buying Shares — Eligible Investors — Class Inst Shares for details.

Same-Fund Exchange Privilege

Shareholders may be eligible to invest in other classes of shares of the same Fund, and may exchange their current shares for another share class if deemed eligible and offered by the Fund. Such same-Fund exchanges could include an exchange of one class for another with higher expenses. Before making such an exchange, you should consider the expenses of each class. Shareholders should contact their financial intermediaries to learn more about the details of the same-Fund exchange privilege. Exchanges out of Class A and Class C shares will be subject to any applicable CDSC. Financial intermediaries that have a customized arrangement with regard to CDSCs are detailed in Appendix A.

Exchanges out of Class C shares to another share class of the same Fund are not permissible on Direct-at-Fund Accounts, except that the Transfer Agent seeks to convert Class C shares as soon as administratively feasible to Class A shares of the same Fund for Direct-at-Fund Accounts that do not or no longer have a financial intermediary assigned to them. Direct-at-Fund Accounts that do not have a financial intermediary assigned to them are not permitted to purchase Class C shares. Class C share purchase orders received by Direct-at-Fund Accounts that do not have a financial intermediary assigned to the account will automatically be invested in Class A shares of the same Fund. Exchanges out of Class C shares to another share class of the same Fund within commissionable brokerage accounts are permitted only (1) when the shareholder moves from a commissionable brokerage account to a fee-based advisory program or (2) when the exchange is part of a share class conversion (or a similar multiple shareholder transaction event) instituted by a financial intermediary and such conversion or similar type event is preapproved by the Distributor.

Ordinarily, shareholders will not recognize a gain or loss for U.S. federal income tax purposes upon a same-Fund exchange. You should consult your tax advisor about your particular exchanges.

Prospectus 2022 57

Columbia Acorn® Fund

Distributions and Taxes

Distributions to Shareholders

A mutual fund can make money two ways:

■ It can earn income on its investments. Examples of fund income are interest paid on money market instruments and bonds, and dividends paid on common stocks.

■ A mutual fund can also have capital gains if the value of its investments increases. While a fund continues to hold an investment, any gain is generally unrealized. If the fund sells an investment, it generally will realize a capital gain if it sells that investment for a higher price than its adjusted cost basis, and will generally realize a capital loss if it sells that investment for a lower price than its adjusted cost basis. Capital gains and losses are either short-term or long-term, depending on whether the fund holds the securities for one year or less (short-term) or more than one year (long-term).

Mutual funds make payments of fund earnings to shareholders, distributing them among all shareholders of the fund. As a shareholder, you are entitled to your portion of a fund's distributed income, including capital gains. Reinvesting your distributions buys you more shares of a fund — which lets you take advantage of the potential for compound growth. Putting the money you earn back into your investment means it, in turn, may earn even more money (or be exposed to additional losses, if the Fund earns a negative return). Over time, the power of compounding has the potential to significantly increase the value of your investment. There is no assurance, however, that you'll earn more money if you reinvest your distributions rather than receive them in cash.

The Fund intends to pay out, in the form of distributions to shareholders, a sufficient amount of its income and gains so that the Fund will qualify for treatment as a regulated investment company and generally will not have to pay any federal excise tax. The Fund generally intends to distribute any net realized capital gain (whether long-term or short-term gain) at least once a year. Normally, the Fund will declare and pay distributions of net investment income according to the following schedule:

Declaration and Distribution Schedule
Declarations	Semiannually
Distributions	Semiannually

The Fund may declare or pay distributions of net investment income more frequently.

Different share classes of the Fund usually pay different net investment income distribution amounts, because each class has different expenses. Each time a distribution is made, the NAV per share of the share class is reduced by the amount of the distribution.

The Fund generally pays cash distributions within five business days after the distribution was declared (or, if the Fund declares distributions daily, within five business days after the end of the month in which the distribution was declared). If you sell all of your shares after the record date, but before the payment date, for a distribution, you'll normally receive that distribution in cash within five business days after the sale was made.

The Fund will automatically reinvest distributions in additional shares of the same share class of the Fund unless you inform us you want to receive your distributions in cash (the financial intermediary through which you purchased shares may have different policies). You can do this by contacting the Funds at the addresses and telephone numbers listed at the beginning of the section entitled Choosing a Share Class. No sales charges apply to the purchase or sale of such shares.

For accounts held directly with the Fund (through the Transfer Agent), distributions of $10 or less will automatically be reinvested in additional Fund shares only. If you elect to receive distributions by check and the check is returned as undeliverable, all subsequent distributions will be reinvested in additional shares of the Fund.

Unless you are a tax-exempt investor or holding Fund shares through a tax-advantaged account (such as a 401(k) plan or IRA), you should consider avoiding buying Fund shares shortly before the Fund makes a distribution (other than distributions of net investment income that are declared daily) of net investment income or net realized capital gain, because doing so can cost you money in taxes to the extent the distribution consists of taxable income or gains. This is because you will, in effect, receive part of your purchase price back in the distribution. This is known as

58 Prospectus 2022

Columbia Acorn® Fund

Distributions and Taxes (continued)

“buying a dividend.” To avoid “buying a dividend,” before you invest check the Fund's distribution schedule, which is available at the Funds' website and/or by calling the Funds' telephone number listed at the beginning of the section entitled Choosing a Share Class.

Taxes

You should be aware of the following considerations applicable to the Fund:

■ The Fund intends to qualify and to be eligible for treatment each year as a regulated investment company. A regulated investment company generally is not subject to tax at the fund level on income and gains from investments that are distributed to shareholders. However, the Fund's failure to qualify for treatment as a regulated investment company would result in Fund-level taxation, and consequently, a reduction in income available for distribution to you and in the NAV of your shares. Even if the Fund qualifies for treatment as a regulated investment company, the Fund may be subject to federal excise tax on certain undistributed income or gains.

■ Otherwise taxable distributions generally are taxable to you when paid, whether they are paid in cash or automatically reinvested in additional Fund shares. Dividends paid in January are deemed paid on December 31 of the prior year if the dividend was declared and payable to shareholders of record in October, November, or December of such prior year.

■ Distributions of the Fund's ordinary income and net short-term capital gain, if any, generally are taxable to you as ordinary income. Distributions of the Fund's net long-term capital gain, if any, generally are taxable to you as long-term capital gain. Whether capital gains are long-term or short-term is determined by how long the Fund has owned the investments that generated them, rather than how long you have owned your shares. Certain events may require the Fund to sell significant amounts of appreciated securities, and make large capital gain dividends relative to the Fund’s NAV. Such events may include large net shareholder redemptions, portfolio re-balancing or fund mergers. The Fund generally provides estimates of expected capital gain dividends (if any) prior to the distribution on columbiathreadneedleus.com.

■ From time to time, a distribution from the Fund could constitute a return of capital. A return of capital is a return of an amount of your original investment and is not a distribution of income or capital gain from the Fund. Therefore, a return of capital is not taxable to you so long as the amount of the distribution does not exceed your tax basis in your Fund shares. A return of capital reduces your tax basis in your Fund shares, with any amounts exceeding such basis generally taxable as capital gain.

■ If you are an individual and you meet certain holding period and other requirements for your Fund shares, a portion of your distributions may be treated as “qualified dividend income” taxable at the lower net long-term capital gain rates instead of the higher ordinary income rates. Qualified dividend income is income attributable to the Fund's dividends received from certain U.S. and foreign corporations, as long as the Fund meets certain holding period and other requirements for the stock producing such dividends.

■ Certain high-income individuals (as well as estates and trusts) are subject to a 3.8% tax on net investment income. For individuals, the 3.8% tax applies to the lesser of (1) the amount (if any) by which the taxpayer's modified adjusted gross income exceeds certain threshold amounts or (2) the taxpayer's “net investment income.”

■ Certain derivative instruments when held in the Fund's portfolio subject the Fund to special tax rules, the effect of which may be to, among other things, accelerate income to the Fund, defer Fund losses, cause adjustments in the holding periods of Fund portfolio securities, or convert capital gains into ordinary income, short-term capital losses into long-term capital losses or long-term capital gains into short-term capital gains. These rules could therefore affect the amount, timing and/or character of distributions to shareholders.

■ Generally, a Fund realizes a capital gain or loss on an option when the option expires, or when it is exercised, sold or otherwise terminated. However, if an option is a “section 1256 contract,” which includes most traded options on a broad-based index, and the Fund holds such option at the end of its taxable year, the Fund is deemed to sell such option at fair market value at such time and recognize any gain or loss thereon, which is generally deemed to be 60% long-term and 40% short-term capital gain or loss, as described further in the SAI.

Prospectus 2022 59

Columbia Acorn® Fund

Distributions and Taxes (continued)

■ A sale, redemption or exchange of Fund shares is a taxable event. This includes redemptions where you are paid in securities. Your sales, redemptions and exchanges of Fund shares (including those paid in securities) usually will result in a taxable capital gain or loss to you, equal to the difference between the amount you receive for your shares (or are deemed to have received in the case of exchanges) and your adjusted tax basis in the shares, which is generally the amount you paid (or are deemed to have paid in the case of exchanges) for them. Any such capital gain or loss generally will be long-term capital gain or loss if you have held your Fund shares for more than one year at the time of sale or exchange. In certain circumstances, capital losses may be converted from short-term to long-term; in other circumstances, capital losses may be disallowed under the “wash sale” rules.

■ For sales, redemptions and exchanges of shares that were acquired in a non-qualified account after 2011, the Fund generally is required to report to shareholders and the Internal Revenue Service (IRS) cost basis information with respect to those shares. The Fund uses average cost basis as its default method of calculating cost basis. For more information regarding average cost basis reporting, other available cost basis methods, and selecting or changing to a different cost basis method, please see the SAI, columbiathreadneedleus.com, or contact the Fund at 800.345.6611. If you hold Fund shares through a financial intermediary (e.g., a brokerage firm), you should contact your financial intermediary to learn about its cost basis reporting default method and the reporting elections available to your account.

■ The Fund is required by federal law to withhold tax on any taxable or tax-exempt distributions and redemption proceeds paid to you (including amounts paid to you in securities and amounts deemed to be paid to you upon an exchange of shares) if: you have not provided a correct TIN or have not certified to the Fund that withholding does not apply, the IRS has notified us that the TIN listed on your account is incorrect according to its records, or the IRS informs the Fund that you are otherwise subject to backup withholding.

 FUNDamentals

Taxes

The information provided above is only a summary of how U.S. federal income taxes may affect your investment in the Fund. It is not intended as a substitute for careful tax planning. Your investment in the Fund may have other tax implications. It does not apply to certain types of investors who may be subject to special rules, including foreign or tax-exempt investors or those holding Fund shares through a tax-advantaged account, such as a 401(k) plan or IRA. Please see the SAI for more detailed tax information. You should consult with your own tax advisor about the particular tax consequences to you of an investment in the Fund, including the effect of any foreign, state and local taxes, and the effect of possible changes in applicable tax laws.

60 Prospectus 2022

Columbia Acorn® Fund

Financial Highlights

The financial highlights table is intended to help you understand the Fund’s financial performance for the past five fiscal years. Certain information reflects financial results for a single Fund share. Per share net investment income (loss) amounts are calculated based on average shares outstanding during the period. The total return in the table represents the rate that an investor would have earned (or lost) on an investment in the Fund assuming all dividends and distributions had been reinvested. Total return does not reflect payment of sales charges, if any. Total return and portfolio turnover are not annualized for periods of less than one year. The portfolio turnover rate is calculated without regard to purchase and sales transactions of short-term instruments and certain derivatives, if any. If such transactions were included, the Fund’s portfolio turnover rate might be higher. The names of certain share classes may have changed during the periods shown below (see Appendix S to the SAI for details). This information has been audited by PricewaterhouseCoopers LLP, an independent registered public accounting firm, whose report, along with the Fund’s financial statements, is included in the Fund’s annual report, which is available upon request. The independent registered public accounting firm’s report and the Fund’s financial statements are also incorporated by reference into the SAI.

Prospectus 2022 61

Columbia Acorn® Fund

Financial Highlights (continued)

	Net asset value, beginning of period	Net investment income (loss)	Net realized and unrealized gain (loss)	Total from investment operations	Distributions from net investment income	Distributions from net realized gains	Total distributions to shareholders
Class A
Year Ended 12/31/2021	$12.69	(0.10)	1.07	0.97	(0.14)	(3.51)	(3.65)
Year Ended 12/31/2020	$11.71	(0.06)	3.24	3.18	—	(2.20)	(2.20)
Year Ended 12/31/2019	$10.65	(0.04)	2.78	2.74	—	(1.68)	(1.68)
Year Ended 12/31/2018	$12.92	(0.03)	(0.48)	(0.51)	—	(1.76)	(1.76)
Year Ended 12/31/2017	$13.35	(0.02)	3.23	3.21	—	(3.64)	(3.64)
Advisor Class
Year Ended 12/31/2021	$17.65	(0.10)	1.54	1.44	(0.13)	(3.59)	(3.72)
Year Ended 12/31/2020	$15.52	(0.05)	4.38	4.33	—	(2.20)	(2.20)
Year Ended 12/31/2019	$13.63	(0.01)	3.58	3.57	—	(1.68)	(1.68)
Year Ended 12/31/2018	$16.06	0.01	(0.64)	(0.63)	—	(1.80)	(1.80)
Year Ended 12/31/2017	$15.83	0.02	3.85	3.87	—	(3.64)	(3.64)
Class C(d)
Year Ended 12/31/2021	$16.14	(0.26)	1.40	1.14	(0.13)	(3.43)	(3.56)
Year Ended 12/31/2020	$16.57	(0.20)	4.08	3.88	—	(4.31)	(4.31)
Year Ended 12/31/2019	$18.75	(0.20)	4.74	4.54	—	(6.72)	(6.72)
Year Ended 12/31/2018	$26.34	(0.24)	(0.71)	(0.95)	—	(6.64)	(6.64)
Year Ended 12/31/2017	$33.36	(0.32)	7.86	7.54	—	(14.56)	(14.56)
Institutional Class
Year Ended 12/31/2021	$16.60	(0.09)	1.43	1.34	(0.13)	(3.59)	(3.72)
Year Ended 12/31/2020	$14.70	(0.04)	4.14	4.10	—	(2.20)	(2.20)
Year Ended 12/31/2019	$12.98	(0.01)	3.41	3.40	—	(1.68)	(1.68)
Year Ended 12/31/2018	$15.39	0.01	(0.62)	(0.61)	—	(1.80)	(1.80)
Year Ended 12/31/2017	$15.29	0.02	3.72	3.74	—	(3.64)	(3.64)
Institutional 2 Class
Year Ended 12/31/2021	$17.88	(0.10)	1.57	1.47	(0.13)	(3.60)	(3.73)
Year Ended 12/31/2020	$15.69	(0.04)	4.43	4.39	—	(2.20)	(2.20)
Year Ended 12/31/2019	$13.76	(0.00) (e)	3.61	3.61	—	(1.68)	(1.68)
Year Ended 12/31/2018	$16.20	0.01	(0.65)	(0.64)	—	(1.80)	(1.80)
Year Ended 12/31/2017	$15.94	0.02	3.88	3.90	—	(3.64)	(3.64)
Institutional 3 Class
Year Ended 12/31/2021	$18.12	(0.09)	1.60	1.51	(0.14)	(3.61)	(3.75)
Year Ended 12/31/2020	$15.87	(0.04)	4.49	4.45	—	(2.20)	(2.20)
Year Ended 12/31/2019	$13.89	0.00(e)	3.66	3.66	—	(1.68)	(1.68)
Year Ended 12/31/2018	$16.34	0.02	(0.66)	(0.64)	—	(1.81)	(1.81)
Year Ended 12/31/2017	$16.04	0.03	3.91	3.94	—	(3.64)	(3.64)

Notes to Financial Highlights
(a)	In addition to the fees and expenses that the Fund bears directly, the Fund indirectly bears a pro rata share of the fees and expenses of any other funds in which it invests, if any. Such indirect expenses are not included in the Fund's reported expense ratios.
(b)	The benefits derived from expense reductions had an impact of less than 0.01%.
(c)	Had the Investment Manager and/or Transfer Agent not waived fees and/or reimbursed a portion of expenses, total return would have been reduced.
(d)	Per share amounts have been adjusted on a retroactive basis to reflect a 4 to 1 reverse stock split completed after the close of business on September 11, 2020.
(e)	Rounds to zero.

62 Prospectus 2022

Columbia Acorn® Fund

Financial Highlights (continued)

	Net asset value, end of period	Total return	Total gross expense ratio to average net assets(a)	Total net expense ratio to average net assets(a)	Net investment income (loss) ratio to average net assets	Portfolio turnover	Net assets, end of period (000's)
Class A
Year Ended 12/31/2021	$10.01	8.79%	1.08%	1.08% (b)	(0.80%)	75%	$919,643
Year Ended 12/31/2020	$12.69	29.18% (c)	1.11%	1.11% (b)	(0.56%)	86%	$983,709
Year Ended 12/31/2019	$11.71	26.21% (c)	1.11%	1.10% (b)	(0.30%)	101%	$810,966
Year Ended 12/31/2018	$10.65	(5.22%) (c)	1.10%	1.08% (b)	(0.20%)	66%	$768,031
Year Ended 12/31/2017	$12.92	24.91%	1.09%	1.08% (b)	(0.13%)	72%	$830,454
Advisor Class
Year Ended 12/31/2021	$15.37	9.03%	0.83%	0.83% (b)	(0.55%)	75%	$39,676
Year Ended 12/31/2020	$17.65	29.44% (c)	0.86%	0.86% (b)	(0.30%)	86%	$44,139
Year Ended 12/31/2019	$15.52	26.58% (c)	0.86%	0.85% (b)	(0.05%)	101%	$44,248
Year Ended 12/31/2018	$13.63	(5.00%) (c)	0.85%	0.83% (b)	0.05%	66%	$40,425
Year Ended 12/31/2017	$16.06	25.19%	0.84%	0.83% (b)	0.12%	72%	$38,588
Class C(d)
Year Ended 12/31/2021	$13.72	7.95%	1.83%	1.83% (b)	(1.54%)	75%	$24,546
Year Ended 12/31/2020	$16.14	28.27% (c)	1.86%	1.86% (b)	(1.30%)	86%	$55,861
Year Ended 12/31/2019	$16.57	25.12% (c)	1.86%	1.85% (b)	(1.05%)	101%	$69,471
Year Ended 12/31/2018	$18.75	(5.86%) (c)	1.85%	1.82% (b)	(0.94%)	66%	$81,149
Year Ended 12/31/2017	$26.34	23.88%	1.84%	1.83% (b)	(0.88%)	72%	$246,450
Institutional Class
Year Ended 12/31/2021	$14.22	8.99%	0.83%	0.83% (b)	(0.55%)	75%	$3,413,006
Year Ended 12/31/2020	$16.60	29.51% (c)	0.86%	0.86% (b)	(0.30%)	86%	$3,569,794
Year Ended 12/31/2019	$14.70	26.60% (c)	0.86%	0.85% (b)	(0.05%)	101%	$3,117,486
Year Ended 12/31/2018	$12.98	(5.09%) (c)	0.85%	0.83% (b)	0.05%	66%	$2,816,948
Year Ended 12/31/2017	$15.39	25.24%	0.84%	0.83% (b)	0.12%	72%	$3,407,214
Institutional 2 Class
Year Ended 12/31/2021	$15.62	9.09% (c)	0.80%	0.80%	(0.52%)	75%	$52,797
Year Ended 12/31/2020	$17.88	29.50% (c)	0.83%	0.82%	(0.27%)	86%	$61,000
Year Ended 12/31/2019	$15.69	26.63% (c)	0.83%	0.82%	(0.02%)	101%	$51,584
Year Ended 12/31/2018	$13.76	(5.00%) (c)	0.81%	0.80%	0.08%	66%	$37,124
Year Ended 12/31/2017	$16.20	25.21%	0.82%	0.81%	0.14%	72%	$67,932
Institutional 3 Class
Year Ended 12/31/2021	$15.88	9.16%	0.75%	0.75%	(0.46%)	75%	$78,955
Year Ended 12/31/2020	$18.12	29.54% (c)	0.78%	0.78%	(0.25%)	86%	$155,338
Year Ended 12/31/2019	$15.87	26.74% (c)	0.78%	0.77%	0.03%	101%	$65,408
Year Ended 12/31/2018	$13.89	(4.98%) (c)	0.76%	0.76%	0.13%	66%	$54,688
Year Ended 12/31/2017	$16.34	25.31%	0.76%	0.76%	0.19%	72%	$47,536

Prospectus 2022 63

Columbia Acorn® Fund

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges

As noted in the Choosing a Share Class section of the prospectus, the sales charge reductions and waivers available to investors who purchase and hold their Fund shares through different financial intermediaries may vary. This Appendix A describes financial intermediary-specific reductions and/or waiver policies applicable to Fund shares purchased and held through the particular financial intermediary. A reduction and/or waiver that is specific to a particular financial intermediary is not available to Direct-at-Fund Accounts and does not apply in any case to non-omnibus positions wherever held. These reductions and/or waivers may apply to purchases, sales, and exchanges of Fund shares. A shareholder transacting in Fund shares through a financial intermediary identified below should carefully read the terms and conditions of the reductions and/or waivers. Please consult your financial intermediary with respect to any sales charge reduction/waiver described below.

The financial intermediary-specific information below may be provided by, or compiled from or based on information provided by, the financial intermediaries noted. While the Funds, the Investment Manager and the Distributor do not establish these financial intermediary-specific policies, our representatives are available to answer questions about these financial intermediary-specific policies and can direct you to the financial intermediary if you need help understanding them.

 Ameriprise Financial Services, LLC (Ameriprise Financial Services)

The following information has been provided by Ameriprise Financial Services:

Class A Shares Front-End Sales Charge Waivers Available at Ameriprise Financial Services:

The following information applies to Class A shares purchases if you have an account with or otherwise purchase Fund shares through Ameriprise Financial Services:

Shareholders purchasing Fund shares through an Ameriprise Financial Services brokerage account are eligible for the following front-end sales charge waivers, which may differ from those disclosed elsewhere in this prospectus or the Fund’s SAI:

■ Employer-sponsored retirement plans (e.g., 401(k) plans, 457 plans, employer-sponsored 403(b) plans, profit sharing and money purchase pension plans and defined benefit plans). For purposes of this provision, employer-sponsored retirement plans do not include SEP IRAs, Simple IRAs or SAR-SEPs.

■ Shares purchased through reinvestment of capital gains distributions and dividend reinvestment when purchasing shares of the same fund (but not any other fund within the Columbia Fund family).

■ Shares exchanged from Class C shares of the same fund in the month of or following the 7-year anniversary of the purchase date. To the extent that the Fund’s Class C Shares – Conversion to Class A Shares policy (stated outside this Appendix A) provides for a waiver with respect to exchanges of Class C shares or the conversion of Class C shares following a shorter holding period, that waiver will apply.

■ Employees and registered representatives of Ameriprise Financial Services or its affiliates and their immediate family members.

■ Shares purchased by or through qualified accounts (including IRAs, Coverdell Education Savings Accounts, 401(k)s, 403(b) TSCAs subject to ERISA and defined benefit plans) that are held by a covered family member, defined as an Ameriprise financial advisor and/or the advisor’s spouse, advisor’s lineal ascendant (mother, father, grandmother, grandfather, great grandmother, great grandfather), advisor’s lineal descendant (son, step-son, daughter, step-daughter, grandson, granddaughter, great grandson, great granddaughter) or any spouse of a covered family member who is a lineal descendant.

■ Shares purchased from the proceeds of redemptions from another fund in the Columbia Fund family, provided (1) the repurchase occurs within 90 days following the redemption, (2) the redemption and purchase occur in the same account, and (3) redeemed shares were subject to a front-end or deferred sales load (i.e. Rights of Reinstatement).

A-1 Prospectus 2022

Columbia Acorn® Fund

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

 Robert W. Baird & Co. Incorporated (Baird)

The following information has been provided by Baird:

Effective June 30, 2020, shareholders purchasing Columbia Fund shares through a Baird platform or account that maintains an omnibus position with the Fund will only be eligible for the following sales charge waivers (front-end sales charge waivers and CDSC waivers) and discounts, which may differ from those disclosed elsewhere in this prospectus or the Fund’s SAI. A reduction and/or waiver that is specific to Baird will not apply to non-omnibus positions.

Front-End Sales Charge Waivers on Class A Shares Available at Baird:

■ Shares purchased through reinvestment of capital gains distributions and dividend reinvestment when purchasing shares of the same Columbia Fund.

■ Share purchases by employees and registered representatives of Baird or its affiliates and their family members as designated by Baird.

■ Shares purchased with the proceeds of redemptions from another Columbia Fund, provided (1) the repurchase occurs within 90 days following the redemption, (2) the redemption and purchase occur in the same accounts, and (3) redeemed shares were subject to a front-end or deferred sales charge (known as rights of reinstatement).

■ A shareholder in the Fund’s Class C shares will have their shares converted at net asset value to Class A shares of the same Columbia Fund if the shares are no longer subject to CDSC and the conversion is in line with the policies and procedures of Baird.

■ Employer-sponsored retirement plans or charitable accounts in a transactional brokerage account at Baird, including 401(k) plans, 457 plans, employer-sponsored 403(b) plans, profit sharing and money purchase pension plans and defined benefit plans. For purposes of this provision, employer-sponsored retirement plans do not include SEP IRAs, Simple IRAs or SAR-SEPs.

CDSC Waivers on Class A and Class C Shares Available at Baird:

■ Shares sold due to death or disability of the shareholder.

■ Shares sold as part of a systematic withdrawal plan as described in this prospectus.

■ Shares purchased due to returns of excess contributions from an IRA account.

■ Shares sold as part of a required minimum distribution for IRA and retirement accounts due to the shareholder reaching the qualified age based on applicable IRS regulations.

■ Shares sold to pay Baird fees but only if the transaction is initiated by Baird.

■ Shares acquired through a right of reinstatement.

Front-End Sales Charge Discounts Available at Baird: Breakpoints and/or Rights of Accumulations:

■ Breakpoints as described in this prospectus.

■ Rights of accumulations which entitle shareholders to breakpoint discounts will be automatically calculated based on the aggregated holding of Columbia Fund assets held by accounts within the purchaser’s household at Baird. Eligible Columbia Fund assets not held at Baird may be included in the rights of accumulations calculation only if the shareholder notifies his or her financial advisor about such assets.

■ Letters of Intent (LOI) allow for breakpoint discounts based on anticipated purchases of Columbia Funds through Baird, over a 13-month period of time.

Prospectus 2022 A-2

Columbia Acorn® Fund

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

 Edward D. Jones & Co., L.P. (Edward Jones)

Policies Regarding Transactions Through Edward Jones

The following information has been provided by Edward Jones:

Effective on or after January 15, 2021, the following information supersedes prior information with respect to transactions and positions held in Columbia Fund shares through an Edward Jones system. Clients of Edward Jones (also referred to as "shareholders") purchasing Columbia Fund shares on the Edward Jones commission and fee-based platforms are eligible only for the following sales charge discounts (also referred to as "breakpoints") and waivers, which can differ from discounts and waivers described elsewhere in this prospectus or the Fund’s SAI or through another broker-dealer. In all instances, it is the shareholder's responsibility to inform Edward Jones at the time of purchase of any relationship, holdings of Columbia Funds and Future Scholars Program, or other facts qualifying the purchaser for discounts or waivers. Edward Jones can ask for documentation of such circumstance. Shareholders should contact Edward Jones if they have questions regarding their eligibility for these discounts and waivers.

Breakpoints

■ Breakpoint pricing, otherwise known as volume pricing, at dollar thresholds as described in this prospectus.

Rights of Accumulation (ROA)

■ The applicable sales charge on a purchase of Class A shares is determined by taking into account all share classes (except certain money market funds and any assets held in group retirement plans) of Columbia Funds and Future Scholars Program held by the shareholder or in an account grouped by Edward Jones with other accounts for the purpose of providing certain pricing considerations ("pricing groups"). If grouping assets as a shareholder, this includes all share classes held on the Edward Jones platform and/or held on another platform. The inclusion of eligible Columbia Fund assets in the ROA calculation is dependent on the shareholder notifying Edward Jones of such assets at the time of calculation. Money market funds are included only if such shares were sold with a sales charge at the time of purchase or acquired in exchange for shares purchased with a sales charge.

■ The employer maintaining a SEP IRA plan and/or SIMPLE IRA plan may elect to establish or change ROA for the IRA accounts associated with the plan to a plan-level grouping as opposed to including all share classes at a shareholder or pricing group level.

■ ROA is determined by calculating the higher of cost minus redemptions or market value (current shares x NAV).

Letter of Intent (LOI)

■ Through a LOI, shareholders can receive the sales charge and breakpoint discounts for purchases shareholders intend to make over a 13-month period from the date Edward Jones receives the LOI. The LOI is determined by calculating the higher of cost or market value of qualifying holdings at LOI initiation in combination with the value that the shareholder intends to buy over a 13-month period to calculate the front-end sales charge and any breakpoint discounts. Each purchase the shareholder makes during that 13-month period will receive the sales charge and breakpoint discount that applies to the total amount. The inclusion of eligible Columbia Fund assets in the LOI calculation is dependent on the shareholder notifying Edward Jones of such assets at the time of calculation. Purchases made before the LOI is received by Edward Jones are not adjusted under the LOI and will not reduce the sales charge previously paid. Sales charges will be adjusted if LOI is not met.

■ If the employer maintaining a SEP IRA plan and/or SIMPLE IRA plan has elected to establish or change ROA for the IRA accounts associated with the plan to a plan-level grouping, LOIs will also be at the plan-level and may only be established by the employer.

A-3 Prospectus 2022

Columbia Acorn® Fund

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

Sales Charge Waivers

Sales charges are waived for the following shareholders and in the following situations:

■ Associates of Edward Jones and its affiliates and their family members who are in the same pricing group (as determined by Edward Jones under its policies and procedures) as the associate. This waiver will continue for the remainder of the associate's life if the associate retires from Edward Jones in good-standing and remains in good standing pursuant to Edward Jones' policies and procedures.

■ Shares purchased in an Edward Jones fee-based program.

■ Shares purchased through reinvestment of capital gains distributions and dividend reinvestment.

■ Shares purchased from the proceeds of redeemed shares of Columbia Funds so long as the following conditions are met: 1) the proceeds are from the sale of shares within 60 days of the purchase, and 2) the sale and purchase are made in the same share class and the same account or the purchase is made in an individual retirement account with proceeds from liquidations in a non-retirement account.

■ Shares exchanged into Class A shares from another share class so long as the exchange is into the same fund and was initiated at the discretion of Edward Jones. Edward Jones is responsible for any remaining CDSC due to the fund company, if applicable. Any future purchases are subject to the applicable sales charge as disclosed in this prospectus.

■ Exchanges from Class C shares to Class A shares of the same fund, generally, in the 84th month following the anniversary of the purchase date or earlier at the discretion of Edward Jones.

Contingent Deferred Sales Charge (CDSC) Waivers

If the shareholder purchases shares that are subject to a CDSC and those shares are redeemed before the CDSC is expired, the shareholder is responsible to pay the CDSC except in the following conditions:

■ The death or disability of the shareholder.

■ Systematic withdrawals with up to 10% per year of the account value.

■ Return of excess contributions from an Individual Retirement Account (IRA).

■ Shares sold as part of a required minimum distribution for IRA and retirement accounts if the redemption is taken in or after the year the shareholder reaches qualified age based on applicable IRS regulations.

■ Shares sold to pay Edward Jones fees or costs in such cases where the transaction is initiated by Edward Jones.

■ Shares exchanged in an Edward Jones fee-based program.

■ Shares acquired through NAV reinstatement.

■ Shares redeemed at the discretion of Edward Jones for Minimum Balances, as described below.

Other Important Information Regarding Transactions Through Edward Jones

Minimum Purchase Amounts

■ Initial purchase minimum: $250

■ Subsequent purchase minimum: none

Minimum Balances

■ Edward Jones has the right to redeem at its discretion Fund holdings with a balance of $250 or less. The following are examples of accounts that are not included in this policy:

■ A fee-based account held on an Edward Jones platform.

■ A 529 account held on an Edward Jones platform.

■ An account with an active systematic investment plan or LOI.

Prospectus 2022 A-4

Columbia Acorn® Fund

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

Exchanging Share Classes

■ At any time it deems necessary, Edward Jones has the authority to exchange at NAV a shareholder's holdings in the Fund to Class A shares.

 Janney Montgomery Scott LLC (Janney)

The following information has been provided by Janney:

Effective May 1, 2020, if you purchase Columbia Fund shares through a Janney brokerage account, you will be eligible for the following load waivers (front-end sales charge waivers and CDSC, or back-end sales charge, waivers) and discounts, which may differ from those disclosed elsewhere in this prospectus or the Fund’s SAI. A reduction and/or waiver that is specific to Janney does not apply to non-omnibus positions.

Front-End Sales Charge* Waivers on Class A Shares Available at Janney

■ Shares purchased through reinvestment of capital gains distributions and dividend reinvestment when purchasing shares of the same fund (but not any other Columbia Fund).

■ Shares purchased by employees and registered representatives of Janney or its affiliates and their family members as designated by Janney.

■ Shares purchased from the proceeds of redemptions from another Columbia Fund, provided (1) the repurchase occurs within ninety (90) days following the redemption, (2) the redemption and purchase occur in the same account, and (3) redeemed shares were subject to a front-end or deferred sales load (i.e., right of reinstatement).

■ Employer-sponsored retirement plans (e.g., 401(k) plans, 457 plans, employer-sponsored 403(b) plans, profit sharing and money purchase pension plans and defined benefit plans). For purposes of this provision, employer-sponsored retirement plans do not include SEP IRAs, Simple IRAs, SAR-SEPs or Keogh plans.

■ Shares acquired through a right of reinstatement.

■ Class C shares that are no longer subject to a CDSC and are converted to Class A shares of the same fund pursuant to Janney’s policies and procedures.

CDSC Waivers on Class A and C Shares Available at Janney

■ Shares sold upon the death or disability of the shareholder.

■ Shares sold as part of a systematic withdrawal plan as described in this prospectus.

■ Shares purchased in connection with a return of excess contributions from an IRA account.

■ Shares sold as part of a required minimum distribution for IRA and retirement accounts if the redemption is taken in or after the year the shareholder reaches qualified age based on applicable IRS regulations.

■ Shares sold to pay Janney fees but only if the transaction is initiated by Janney.

■ Shares acquired through a right of reinstatement.

■ Shares exchanged into the same share class of a different fund.

Front-End Sales Charge* Discounts Available at Janney: Breakpoints, Rights of Accumulation, and/or Letters of Intent

■ Breakpoints as described in this prospectus.

■ Rights of accumulation (“ROA”), which entitle shareholders to breakpoint discounts, will be automatically calculated based on the aggregated holding of Columbia Fund assets held by accounts within the purchaser’s household at Janney. Eligible Columbia Fund assets not held at Janney may be included in the ROA calculation only if the shareholder notifies his or her financial advisor about such assets.

■ Letters of intent which allow for breakpoint discounts based on anticipated purchases within the Columbia Funds, over a 13-month time period. Eligible Columbia Fund assets not held at Janney may be included in the calculation of letters of intent only if the shareholder notifies his or her financial advisor about such assets.

A-5 Prospectus 2022

Columbia Acorn® Fund

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

* Also referred to as an “initial sales charge”.

 Merrill Lynch Pierce, Fenner & Smith Incorporated (Merrill Lynch)

The following information has been provided by Merrill Lynch:

Shareholders purchasing Columbia Fund shares through a Merrill Lynch platform or account will be eligible only for the following load waivers (front-end sales charge waivers and contingent deferred, or back-end, sales charge waivers) and discounts, which may differ from those disclosed elsewhere in this prospectus or the Fund’s SAI:

Front-End Load Discounts Available at Merrill Lynch:

Merrill Lynch makes available breakpoint discounts on shares of the Fund through:

■ Breakpoints as described in this prospectus.

■ Rights of Accumulation (ROA) which entitle shareholders to breakpoint discounts as described in this prospectus will be automatically calculated based on the aggregated holding of Columbia Fund assets held by accounts (including 529 program holdings, where applicable) within the purchaser’s household at Merrill Lynch. Eligible Columbia Fund assets not held at Merrill Lynch may be included in the ROA calculation only if the shareholder notifies his or her financial advisor about such assets.

■ Letters of Intent (LOI) which allow for breakpoint discounts based on anticipated purchases of Columbia Funds, through Merrill Lynch, over a 13-month period of time (if applicable).

Front-End Sales Load Waivers on Class A Shares Available at Merrill Lynch:

■ Employer-sponsored retirement, deferred compensation and employee benefit plans (including health savings accounts) and trusts used to fund those plans, provided that the shares are not held in a commission-based brokerage account and shares are held for the benefit of the plan.

■ Shares purchased by a 529 Plan (does not include 529 Plan units or 529-specific share classes or equivalents).

■ Shares purchased through a Merrill Lynch affiliated investment advisory program.

■ Shares exchanged due to the holdings moving from a Merrill Lynch affiliated investment advisory program to a Merrill Lynch brokerage (non-advisory) account pursuant to Merrill Lynch’s policies relating to sales load discounts and waivers.

■ Shares purchased by third party investment advisors on behalf of their advisory clients through Merrill Lynch’s platform.

■ Shares of funds purchased through the Merrill Edge Self-Directed platform (if applicable).

■ Shares purchased through reinvestment of capital gains distributions and dividend reinvestment when purchasing shares of the same fund (but not any other Columbia Fund).

■ Shares exchanged from Class C (i.e., level-load) shares of the same fund pursuant to Merrill Lynch’s policies relating to sales load discounts and waivers.

■ Employees and registered representatives of Merrill Lynch or its affiliates and their family members.

■ Directors or Trustees of the Fund, and employees of the Fund’s investment adviser or any of its affiliates, as described in this prospectus.

■ Eligible shares purchased from the proceeds of redemptions from another Columbia Fund, provided (1) the repurchase occurs within 90 days following the redemption, (2) the redemption and purchase occur in the same account, and (3) redeemed shares were subject to a front-end or deferred sales load (known as Rights of Reinstatement). Automated transactions (i.e. systematic purchases and withdrawals) and purchases made after shares are automatically sold to pay Merrill Lynch’s account maintenance fees are not eligible for reinstatement.

CDSC Waivers on Class A and C Shares Available at Merrill Lynch:

■ Death or disability of the shareholder.

Prospectus 2022 A-6

Columbia Acorn® Fund

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

■ Shares sold as part of a systematic withdrawal plan as described in this prospectus.

■ Return of excess contributions from an IRA Account.

■ Shares sold as part of a required minimum distribution for IRA and retirement accounts pursuant to the Internal Revenue Code.

■ Shares sold to pay Merrill Lynch fees but only if the transaction is initiated by Merrill Lynch.

■ Shares acquired through a right of reinstatement.

■ Shares held in retirement brokerage accounts, that are exchanged for a lower cost share class due to transfer to certain fee based accounts or platforms (applicable to Class A and Class C shares only).

■ Shares received through an exchange due to the holdings moving from a Merrill Lynch affiliated investment advisory program to a Merrill Lynch brokerage (non-advisory) account pursuant to Merrill Lynch’s policies relating to sales load discounts and waivers.

 Morgan Stanley Smith Barney, LLC (Morgan Stanley Wealth Management)

The following information has been provided by Morgan Stanley Wealth Management:

Effective July 1, 2018, shareholders purchasing Columbia Fund shares through a Morgan Stanley Wealth Management transactional brokerage account will be eligible only for the following front-end sales charge waivers with respect to Class A shares, which may differ from and may be more limited than those disclosed elsewhere in this prospectus or the Fund’s SAI.

Front-End Sales Charge Waivers on Class A Shares Available at Morgan Stanley Wealth Management Effective July 1, 2018:

■ Employer-sponsored retirement plans (e.g., 401(k) plans, 457 plans, employer-sponsored 403(b) plans, profit sharing and money purchase pension plans and defined benefit plans).  For purposes of this provision, employer-sponsored retirement plans do not include SEP IRAs, Simple IRAs, SAR-SEPs or Keogh plans.

■ Morgan Stanley employee and employee-related accounts according to Morgan Stanley’s account linking rules.

■ Shares purchased through reinvestment of dividends and capital gains distributions when purchasing shares of the same fund.

■ Shares purchased through a Morgan Stanley self-directed brokerage account.

■ Class C (i.e., level-load) shares that are no longer subject to a CDSC and are exchanged for Class A shares of the same fund pursuant to Morgan Stanley Wealth Management’s share class exchange program.

■ Shares purchased from the proceeds of redemptions from another Columbia Fund, provided (i) the repurchase occurs within 90 days following the redemption, (ii) the redemption and purchase occur in the same account, and (iii) redeemed shares were subject to a front-end or deferred sales charge.

 Raymond James & Associates, Inc., Raymond James Financial Services, Inc. and each entity’s affiliates (Raymond James)

The following information has been provided by Raymond James:

Intermediary-Defined Sales Charge Waiver Policies:

The availability of certain initial or deferred sales charge waivers and discounts may depend on the particular financial intermediary or type of account through which you purchase or hold Columbia Fund shares.

Intermediaries may have different policies and procedures regarding the availability of front-end sales load waivers or contingent deferred (back-end) sales load (CDSC) waivers, which are discussed below. In all instances, it is the purchaser’s responsibility to notify the Fund or the purchaser’s financial intermediary at the time of purchase of any

A-7 Prospectus 2022

Columbia Acorn® Fund

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

relationship or other facts qualifying the purchaser for sales charge waivers or discounts. For waivers and discounts not available through a particular intermediary, shareholders will have to purchase Columbia Fund shares directly from the Fund or through another intermediary to receive these waivers or discounts.

Raymond James:

Effective March 1, 2019, shareholders purchasing Columbia Fund shares through a Raymond James platform or account, or through an introducing broker-dealer or independent registered investment adviser for which Raymond James provides trade execution, clearance, and/or custody services, will be eligible only for the following load waivers (front-end sales charge waivers and contingent deferred, or back-end, sales charge waivers) and discounts, which may differ from those disclosed elsewhere in this prospectus or the Fund’s SAI.

Front-End Sales Load Waivers on Class A Shares Available at Raymond James:

■ Shares purchased in an investment advisory program.

■ Shares purchased within the Columbia Funds through a systematic reinvestment of capital gains and dividend distributions.

■ Employees and registered representatives of Raymond James or its affiliates and their family members as designated by Raymond James.

■ Shares purchased from the proceeds of redemptions within the Columbia Funds, provided (1) the repurchase occurs within 90 days following the redemption, (2) the redemption and purchase occur in the same account, and (3) redeemed shares were subject to a front-end or deferred sales load (known as Rights of Reinstatement).

■ A shareholder in the Fund’s Class C shares will have their shares converted at net asset value to Class A shares (or the appropriate share class) of the Fund if the shares are no longer subject to a CDSC and the conversion is in line with the policies and procedures of Raymond James.

CDSC Waivers on Class A and Class C Shares Available at Raymond James:

■ Death or disability of the shareholder.

■ Shares sold as part of a systematic withdrawal plan as described in this prospectus.

■ Return of excess contributions from an IRA Account.

■ Shares sold as part of a required minimum distribution for IRA and retirement accounts due to the shareholder reaching the qualified age based on applicable IRS regulations as described in this prospectus.

■ Shares sold to pay Raymond James fees but only if the transaction is initiated by Raymond James.

■ Shares acquired through a right of reinstatement.

Front-End Load Discounts Available at Raymond James: Breakpoints, Rights of Accumulation and/or Letters of Intent:

■ Breakpoints as described in this prospectus.

■ Rights of accumulation which entitle shareholders to breakpoint discounts will be automatically calculated based on the aggregated holding of Columbia Fund assets held by accounts within the purchaser’s household at Raymond James. Eligible Columbia Fund assets not held at Raymond James may be included in the calculation of rights of accumulation only if the shareholder notifies his or her financial advisor about such assets.

■ Letters of intent which allow for breakpoint discounts based on anticipated purchases within the Columbia Funds, over a 13-month time period. Eligible Columbia Fund assets not held at Raymond James may be included in the calculation of letters of intent only if the shareholder notifies his or her financial advisor about such assets.

 Stifel Financial Corp. (Stifel)

The following information has been provided by Stifel:

Prospectus 2022 A-8

Columbia Acorn® Fund

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

Effective June 30, 2020, Class C shares of Columbia Funds that were purchased through a Stifel platform or account that maintains an omnibus position with the Fund that are no longer subject to a CDSC are exchanged to Class A shares of the same Columbia Fund pursuant to Stifel’s policies and procedures. This does not apply to non-omnibus positions.

 U.S. Bancorp Investments, Inc. (USBI)

The following information has been provided by USBI:

Effective September of 2021, shareholders purchasing Columbia Fund shares through a USBI platform or who own shares for which USBI is the broker-dealer, where the shares are held in an omnibus account, will only be eligible for the following front-end sales charge waivers and discounts, which may differ from those disclosed elsewhere in this prospectus or the Fund’s SAI.

All other sales charge waivers and reduction described elsewhere in this prospectus or the Fund’s SAI still apply.

USBI Conversion of Class C shares

Class C (i.e., level-load) shares that are no longer subject to a contingent deferred sales charge are systematically converted to the Class A shares of the same fund pursuant to USBI’s share class exchange policy.

 Additional Sales Charge Reductions and/or Waivers Available at Certain Financial Intermediaries

Shareholders purchasing Columbia Fund shares through a platform or account of RBC Capital Markets, LLC are eligible for the following sales charge waiver:

Class A Shares Front-End Sales Charge Waiver Available at RBC Capital Markets, LLC:

■ For employer-sponsored retirement plans held through a commissionable brokerage account, Class A shares are available at NAV (i.e., without a sales charge). For this purpose, employer-sponsored retirement plans include, but are not limited to, 401(k) plans, 457 plans, employer-sponsored 403(b) plans, profit sharing and money purchase pension plans and defined benefit plans. For purposes of this provision, employer-sponsored retirement plans do not include SEP IRAs, Simple IRAs, SAR-SEPs or Keogh plans.

A-9 Prospectus 2022

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Columbia Acorn^® Fund

P.O. Box 219104
Kansas City, MO 64121-9104

Columbia Acorn Family of Funds

Additional Information About the Fund

Additional information about the Fund’s investments is available in the Fund’s annual and semiannual reports to shareholders. In the annual report, you will find a discussion of the market conditions and investment strategies that significantly affected the Fund’s performance during its last fiscal year. The SAI also provides additional information about the Fund and its policies. The SAI, which has been filed with the SEC, is legally part of this prospectus (incorporated by reference). To obtain these documents free of charge, to request other information about the Fund and to make shareholder inquiries, please contact the Fund as follows:

By Mail:  Columbia Management Investment Services Corp.
P.O. Box 219104
Kansas City, MO 64121-9104

By Telephone: 800.345.6611

Online: columbiathreadneedleus.com

Shareholder Communications with the Board

The Fund’s Board of Trustees has adopted procedures by which shareholders may communicate with the Board. Shareholders who wish to communicate with the Board should send their written communications to the Board by mail, c/o Columbia Wanger Asset Management, LLC, 71 S. Wacker Drive, Suite 2500, Chicago, IL 60606, Attention: Secretary. Shareholder communications must (i) be in writing, (ii) identify the Columbia Acorn Fund to which the communication relates and (iii) state the particular class of shares and number of shares held by the communicating shareholder.

Obtaining Additional Information from the SEC

Reports and other information about the Fund are also available in the EDGAR Database on the SEC’s website at http://www.sec.gov. You can receive copies of this information, for a duplication fee, by electronic request at the following e-mail address: publicinfo@sec.gov.

The investment company registration number of Columbia Acorn Trust, of which the Fund is a series, is 811-01829.

Columbia Threadneedle Investments is the global brand name of the Columbia and Threadneedle group of companies.
The Fund is distributed by Columbia Management Investment Distributors, Inc., 290 Congress Street, Boston, MA 02210.

© 2022 Columbia Management Investment Advisers, LLC. All rights reserved.

PRO110_12_M01_(05/22)

 

Prospectus

May 1, 2022

Columbia Acorn Family of Funds

Managed by Columbia Wanger Asset Management, LLC

Columbia
  Acorn International®

Class	Ticker Symbol
A	LAIAX
Advisor (Class Adv)	CCIRX
C	LAICX
Institutional (Class Inst)	ACINX

Class	Ticker Symbol
Institutional 2 (Class Inst2)	CAIRX
Institutional 3 (Class Inst3)	CCYIX
R	CACRX

As with all mutual funds, the Securities and Exchange Commission (SEC) has not approved or disapproved these securities or passed upon the adequacy of this prospectus. Any representation to the contrary is a criminal offense.

Table of Contents

Summary of the Fund	3
Investment Objective	3
Fees and Expenses of the Fund	3
Principal Investment Strategies	4
Principal Risks	5
Performance Information	9
Fund Management	10
Purchase and Sale of Fund Shares	11
Tax Information	11
Payments to Broker-Dealers and Other Financial Intermediaries	11
More Information About the Fund	12
Investment Objective	12
Principal Investment Strategies	12
Principal Risks	12
Additional Investment Strategies and Policies	18
Board of Trustees	23
Primary Service Provider Contracts	24
Other Roles and Relationships of Ameriprise Financial and its Affiliates — Certain Conflicts of Interest	26
Certain Legal Matters	27
Choosing a Share Class	28
The Funds	28
Summary of Share Class Features	28
Sales Charges and Commissions	34
Reductions/Waivers of Sales Charges	37
Distribution and Service Fees	41
Financial Intermediary Compensation	42
Buying, Selling and Exchanging Shares	44
Share Price Determination	44
Transaction Rules and Policies	45
Opening an Account and Placing Orders	49
Buying Shares	51
Selling Shares	56
Exchanging Shares	58
Distributions and Taxes	61
Distributions to Shareholders	61
Taxes	62
Financial Highlights	65
Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges	A-1

2

Columbia Acorn International®

Summary of the Fund

Investment Objective

Columbia Acorn International^® (the Fund) seeks long-term capital appreciation.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below. You may qualify for sales charge discounts if you and members of your immediate family invest, or agree to invest in the future, at least $50,000 in certain classes of shares of eligible funds distributed by Columbia Management Investment Distributors, Inc. (the Distributor). More information is available about these and other sales charge discounts and waivers from your financial intermediary, and can be found in the Choosing a Share Class section beginning on page 28 of the Fund’s prospectus, in Appendix A to the prospectus beginning on page A-1 and in Appendix S to the Statement of Additional Information (SAI) under Sales Charge Waivers beginning on page S-1.

Shareholder Fees (fees paid directly from your investment)
	Class A	Class C	Classes Adv, Inst, Inst2, Inst3 and R
Maximum sales charge (load) imposed on purchases (as a % of offering price)	5.75%	None	None
Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)	1.00%(a)	1.00%(b)	None

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
	Class A	Class Adv	Class C	Class Inst	Class Inst2	Class Inst3	Class R
Management fees	0.79%	0.79%	0.79%	0.79%	0.79%	0.79%	0.79%
Distribution and/or service (12b-1) fees	0.25%	0.00%	1.00%	0.00%	0.00%	0.00%	0.50%
Other expenses	0.20%	0.20%	0.20%	0.20%	0.16%	0.10%	0.20%
Total annual Fund operating expenses(c)	1.24%	0.99%	1.99%	0.99%	0.95%	0.89%	1.49%
Less: Fee waivers and/or expense reimbursements(d)	(0.01%)	(0.01%)	(0.01%)	(0.01%)	(0.03%)	(0.01%)	(0.01%)
Total annual Fund operating expenses after fee waivers and/or expense reimbursements	1.23%	0.98%	1.98%	0.98%	0.92%	0.88%	1.48%

(a)	This charge is imposed on certain investments of between $1 million and $50 million redeemed within 18 months after purchase, as follows: 1.00% if redeemed within 12 months after purchase, and 0.50% if redeemed more than 12, but less than 18, months after purchase, with certain limited exceptions.
(b)	This charge applies to redemptions within 12 months after purchase, with certain limited exceptions.

(c)

“Total annual Fund operating expenses” include acquired fund fees and expenses (expenses the Fund incurs indirectly through its investments in other investment companies) and may be higher than the ratio of expenses to average net assets shown in the Financial Highlights section of this prospectus because the ratio of expenses to average net assets does not include acquired fund fees and expenses.

(d)

Columbia Wanger Asset Management, LLC (the Investment Manager) has contractually agreed to waive fees and reimburse certain expenses of the Fund, through April 30, 2023, so that ordinary operating expenses (excluding transaction costs and certain other investment-related expenses, interest and fees on borrowings and expenses associated with the Fund's investment in other investment companies, if any) do not exceed the annual rates of 1.23% for Class A shares, 0.98% for Class Adv shares, 1.98% for Class C shares, 0.98% for Class Inst shares, 0.92% for Class Inst2 shares, 0.88% for Class Inst3 shares and 1.48% for Class R shares. This arrangement may only be amended or terminated with approval from the Fund's Board of Trustees and the Investment Manager. The fee waivers and/or expense reimbursements shown in the table also reflect the contractual agreement of the Fund's transfer agent, Columbia Management Investment Services Corp. (the Transfer Agent), to waive a portion of its fees through April 30, 2023, such that the Fund's transfer agency fees do not exceed the annual rates of 0.04% of the average daily net assets of Class Inst2 shares and 0.00% of the average daily net assets of Class Inst3 shares. This arrangement may be terminated at the sole discretion of the Fund's Board of Trustees.

Prospectus 2022 3

Columbia Acorn International®

Summary of the Fund (continued)

 Example

The following example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example illustrates the hypothetical expenses that you would incur over the time periods indicated, and assumes that:

■ you invest $10,000 in the applicable class of Fund shares for the periods indicated,

■ your investment has a 5% return each year, and

■ the Fund’s total annual operating expenses remain the same as shown in the Annual Fund Operating Expenses table above.

Since the waivers and/or reimbursements shown in the Annual Fund Operating Expenses table above expire as indicated in the preceding table, they are only reflected in the 1 year example and the first year of the other examples. Although your actual costs may be higher or lower, based on the assumptions listed above, your costs would be:

	1 year	3 years	5 years	10 years
Class A (whether or not shares are redeemed)	$693	$945	$1,216	$1,988
Class Adv (whether or not shares are redeemed)	$100	$314	$546	$1,212
Class C (assuming redemption of all shares at the end of the period)	$301	$623	$1,072	$2,122
Class C (assuming no redemption of shares)	$201	$623	$1,072	$2,122
Class Inst (whether or not shares are redeemed)	$100	$314	$546	$1,212
Class Inst2 (whether or not shares are redeemed)	$94	$300	$523	$1,164
Class Inst3 (whether or not shares are redeemed)	$90	$283	$492	$1,095
Class R (whether or not shares are redeemed)	$151	$470	$812	$1,779

Portfolio Turnover

The Fund may pay transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 27% of the average value of its portfolio.

Principal Investment Strategies

Under normal circumstances, the Fund invests at least 75% of its net assets in foreign companies in developed markets (for example, Japan, Canada and the United Kingdom) and in emerging markets (for example, China, India and Brazil).

Under normal circumstances, the Fund invests a majority of its net assets in the common stock of small- and mid-sized companies with market capitalizations generally in the range of market capitalizations in the MSCI ACWI ex USA SMID Cap Growth Index (Net), the Fund's primary benchmark, (the Index) at the time of purchase (between $55.8 million and $29.7 billion as of March 31, 2022). The market capitalization range and composition of companies in the Index are subject to change. As such, the size of the companies in which the Fund invests may change. The Fund determines a company’s market capitalization at the time of investment. As long as a majority of its net assets are invested in companies within the Index, the Fund may continue to hold and make new investments in a security even if the company’s market capitalization grows beyond the market capitalization of the largest company within the Index or falls below the market capitalization of the smallest company within the Index. The Investment Manager from time to time emphasizes one or more sectors in selecting the Fund’s investments, including the industrials and information technology sectors. 

4 Prospectus 2022

Columbia Acorn International®

Summary of the Fund (continued)

Columbia Wanger Asset Management, LLC, the Fund's investment adviser (the Investment Manager), believes that stocks of small- and mid-sized companies, which generally are not as well known by financial analysts as larger companies, may offer higher return potential than stocks of larger companies. The Fund also may invest in larger-sized companies. 

The Investment Manager typically seeks companies with: 

■ A strong business franchise that offers growth potential. 

■ Products and services in which the company has a competitive advantage. 

■ A stock price the Investment Manager believes is reasonable relative to the assets and earning power of the company. 

The Investment Manager may sell a portfolio holding if the security reaches the Investment Manager's price target, if the company has a deterioration of fundamentals, such as failing to meet key operating benchmarks, or if the Investment Manager believes other securities are more attractive. The Investment Manager also may sell a portfolio holding to fund redemptions. 

Principal Risks

An investment in the Fund involves risks, including those described below, among others. There is no assurance that the Fund will achieve its investment objective and you may lose money. The value of the Fund’s holdings may decline, and the Fund’s net asset value (NAV) and share price may go down. An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Active Management Risk. The Investment Manager’s active management of the Fund could cause the Fund to underperform its benchmark index and/or other funds with similar investment objectives and/or strategies.

Market Risk. The Fund may incur losses due to declines in the value of one or more securities in which it invests. These declines may be due to factors affecting a particular issuer, or the result of, among other things, political, regulatory, market, economic or social developments affecting the relevant market(s) more generally. In addition, turbulence in financial markets and reduced liquidity in equity, credit and/or fixed income markets may negatively affect many issuers, which could adversely affect the Fund’s ability to price or value hard-to-value assets in thinly traded and closed markets and could cause significant redemptions and operational challenges. Global economies and financial markets are increasingly interconnected, and conditions and events in one country, region or financial market may adversely impact issuers in a different country, region or financial market. These risks may be magnified if certain events or developments adversely interrupt the global supply chain; in these and other circumstances, such risks might affect companies worldwide. As a result, local, regional or global events such as terrorism, war, other conflicts, natural disasters, disease/virus outbreaks and epidemics or other public health issues, recessions, depressions or other events – or the potential for such events – could have a significant negative impact on global economic and market conditions. 

The large-scale invasion of Ukraine by Russia in February 2022 has resulted in sanctions and market disruptions including declines in regional and global stock and commodity markets and significant devaluations of Russian currency. The extent and duration of the military action are impossible to predict but could be significant. Market disruption caused by the Russian military action, and any counter measures or responses thereto (including international sanctions, a downgrade in the country’s credit rating, purchasing and financing restrictions, boycotts, tariffs, changes in consumer or purchaser preferences, cyberattacks and espionage) could have severe adverse impacts on regional and/or global securities and commodities markets, including markets for oil and natural gas. These impacts may include reduced market liquidity, distress in credit markets, further disruption of global supply chains, increased risk of inflation, and limited access to investments in certain international markets and/or issuers. These developments and other related events could negatively impact Fund performance. 

The pandemic caused by coronavirus disease 2019 and its variants (COVID-19) has resulted in, and may continue to result in, significant global economic and societal disruption and market volatility due to disruptions in market access, resource availability, facilities operations, imposition of tariffs, export controls and supply chain disruption, among others. Such disruptions may be caused, or exacerbated by, quarantines and travel restrictions, workforce 

Prospectus 2022 5

Columbia Acorn International®

Summary of the Fund (continued)

displacement and loss in human and other resources. The uncertainty surrounding the magnitude, duration, reach, costs and effects of the global pandemic, as well as actions that have been or could be taken by governmental authorities or other third parties, present unknowns that are yet to unfold. The impacts, as well as the uncertainty over impacts to come, of COVID-19 – and any other infectious illness outbreaks, epidemics and pandemics that may arise in the future – could negatively affect global economies and markets in ways that cannot necessarily be foreseen. In addition, the impact of infectious illness outbreaks and epidemics in less developed countries may be greater due to generally less established healthcare systems, governments and financial markets. Public health crises caused by the COVID-19 outbreak may exacerbate other pre-existing political, social and economic risks in certain countries or globally. The disruptions caused by COVID-19 could prevent the Fund from executing advantageous investment decisions in a timely manner and negatively impact the Fund’s ability to achieve its investment objective. Any such events could have a significant adverse impact on the value and risk profile of the Fund. 

Small- and Mid-Cap Company Securities Risk. Investments in small- and mid-cap companies often involve greater risks than investments in larger, more established companies because small- and mid-cap companies tend to have less predictable earnings and may lack the management experience, financial resources, product diversification and competitive strengths of larger companies. Securities of small- and mid-cap companies may be less liquid and more volatile than the securities of larger companies. 

Foreign Securities Risk. Investments in or exposure to securities of foreign companies may involve heightened risks relative to investments in or exposure to securities of U.S. companies. Investing in securities of foreign companies subjects the Fund to the risks associated with an issuer’s (and any of its related companies’) country of organization and places of business operations, including risks related to political, regulatory, economic, social, diplomatic and other conditions or events (including, for example, military confrontations and actions, war, other conflicts, terrorism and disease/virus outbreaks and epidemics) occurring in the country or region, as well as risks associated with less developed custody and settlement practices. Foreign securities may be more volatile and less liquid than securities of U.S. companies, and are subject to the risks associated with potential imposition of economic and other sanctions against a particular foreign country, its nationals or industries or businesses within the country. In addition, foreign governments may impose withholding or other taxes on the Fund’s income, capital gains or proceeds from the disposition of foreign securities, which could reduce the Fund’s return on such securities. 

Operational and Settlement Risks of Foreign Securities. The Fund’s foreign securities are generally held outside the United States in the primary market for the securities in the custody of foreign sub-custodians. Some countries have limited governmental oversight and regulation, which increases the risk of corruption and fraud and the possibility of losses to the Fund. In particular, under certain circumstances, foreign securities may settle on a delayed delivery basis, meaning that the Fund may be required to make payment for securities before the Fund has actually received delivery of the securities or deliver securities prior to the receipt of payment. As a result, there is a risk that the security will not be delivered to the Fund or that payment will not be received. Losses can also result from lost, stolen or counterfeit securities; defaults by brokers and banks; failures or defects of the settlement system; or poor and improper record keeping by registrars and issuers. 

Share Blocking. In certain non-U.S. markets, an issuer’s securities are blocked from trading for a specified number of days before and, in certain instances, after a shareholder meeting. The blocking period can last up to several weeks. Share blocking may prevent the Fund from buying or selling securities during this period. As a consequence of these restrictions, the Investment Manager, on behalf of the Fund, may abstain from voting proxies in markets that require share blocking. 

Emerging Market Securities Risk. Securities issued by foreign governments or companies in emerging market countries, such as China, Russia and certain countries in Eastern Europe, the Middle East, Asia, Latin America or Africa, are more likely to have greater exposure to the risks of investing in foreign securities that are described in Foreign Securities Risk. In addition, emerging market countries are more likely to experience instability resulting, for example, from rapid changes or developments in social, political, economic or other conditions. Their economies are usually less mature and their securities markets are typically less developed with more limited trading activity (i.e., lower trading volumes and less liquidity) than more developed countries. Emerging market securities tend to be more volatile, and may be more susceptible to market manipulation, than securities in more developed markets. 

6 Prospectus 2022

Columbia Acorn International®

Summary of the Fund (continued)

Many emerging market countries are heavily dependent on international trade and have fewer trading partners, which makes them more sensitive to world commodity prices and economic downturns in other countries, and some have a higher risk of currency devaluations. Due to the differences in the nature and quality of financial information of issuers of emerging market securities, including auditing and financial reporting standards, financial information and disclosures about such issuers may be unavailable or, if made available, may be considerably less reliable than publicly available information about other foreign securities. 

Operational and Settlement Risks of Securities in Emerging Markets. Foreign sub-custodians in emerging markets may be recently organized, lack extensive operating experience or lack effective government oversight or regulation. In addition, there may be legal restrictions or limitations on the ability of the Fund to recover assets held in custody by a foreign sub-custodian in the event of the bankruptcy of the sub-custodian. There may also be a greater risk that settlement may be delayed and that cash or securities of the Fund may be lost because of failures of or defects in the system, including fraud or corruption. Settlement systems in emerging markets also have a higher risk of failed trades. 

Risks Related to Currencies and Corporate Actions in Emerging Markets. Risks related to currencies and corporate actions are also greater in emerging market countries than in developed countries. Emerging market currencies may not have an active trading market and are subject to a higher risk of currency devaluations. 

Risks Related to Corporate and Securities Laws in Emerging Markets. Securities laws in emerging markets may be relatively new and unsettled and, consequently, there is a risk of rapid and unpredictable change in laws regarding foreign investment, securities regulation, title to securities and shareholder rights. 

Liquidity and Trading Volume Risk. Due to market conditions, including uncertainty regarding the price of a security, it may be difficult for the Fund to buy or sell portfolio securities at a desirable time or price, which could result in investment losses. This risk of portfolio illiquidity is heightened with respect to small- and mid-cap securities, generally, and foreign small- and mid-cap securities in particular. The Fund may have to lower the selling price, liquidate other investments, or forego another, more appealing investment opportunity as a result of illiquidity in the markets. The Fund may also be limited in its ability to execute favorable trades in portfolio securities in response to changes in share prices and fundamentals, and may be forced to dispose of securities under disadvantageous circumstances and at a loss. As the Fund grows in size or, conversely, if it faces significant redemption pressure, these considerations take on increasing significance and may adversely impact performance. 

Geographic Focus Risk. The Fund may be particularly susceptible to risks related to economic, political, regulatory or other events or conditions affecting issuers and countries within the specific geographic regions in which the Fund invests. The Fund’s NAV may be more volatile than the NAV of a more geographically diversified fund. 

■ Asia Pacific Region. Many of the countries in the Asia Pacific region are considered underdeveloped or developing, including from a political, economic and/or social perspective, and may have relatively unstable governments and economies based on limited business, industries and/or natural resources or commodities. Events in any one country within the region may impact other countries in the region or the region as a whole. As a result, events in the region will generally have a greater effect on the Fund than if the Fund were more geographically diversified. This could result in increased volatility in the value of the Fund’s investments and losses for the Fund. Also, securities of some companies in the region can be less liquid than U.S. or other foreign securities, potentially making it difficult for the Fund to sell such securities at a desirable time and price. 

■ Europe. The Fund is particularly susceptible to risks related to economic, political, regulatory or other events or conditions, including acts of war or other conflicts in the region, affecting issuers and countries in Europe. Countries in Europe are often closely connected and interdependent, and events in one European country can have an adverse impact on, and potentially spread to, other European countries. In addition, significant private and public sectors’ debt problems of a single European Union (EU) country can pose economic risks to the EU as a whole. As a result, the Fund’s NAV may be more volatile than the NAV of a more geographically diversified fund. If securities of issuers in Europe fall out of favor, it may cause the Fund to underperform other funds that do not focus their investments in this region of the world. The departure of the United Kingdom (UK) from the EU single market became effective January 1, 2021 with the end of the Brexit transition period and the post-Brexit trade deal between the UK and EU taking effect on December 31, 2020. The impact of any partial or complete dissolution of 

Prospectus 2022 7

Columbia Acorn International®

Summary of the Fund (continued)

the EU on the UK and European economies and the broader global economy could be significant, resulting in negative impacts on currency and financial markets generally, such as increased volatility and illiquidity, and potentially lower economic growth in markets in Europe, which may adversely affect the value of your investment in the Fund. 

■ Japan. The Fund is particularly susceptible to the social, political, economic, regulatory and other conditions or events that may affect Japan’s economy. The Japanese economy is heavily dependent upon international trade, including, among other things, the export of finished goods and the import of oil and other commodities and raw materials. Because of its trade dependence, the Japanese economy is particularly exposed to the risks of currency fluctuation, foreign trade policy and regional and global economic disruption, including the risk of increased tariffs, embargoes, and other trade limitations or factors. Strained relationships between Japan and its neighboring countries, including China, South Korea and North Korea, based on historical grievances, territorial disputes, and defense concerns, may also cause uncertainty in Japanese markets. As a result, additional tariffs, other trade barriers, or boycotts may have an adverse impact on the Japanese economy. Japanese government policy has been characterized by economic regulation, intervention, protectionism and large government deficits. The Japanese economy is also challenged by an unstable financial services sector, highly leveraged corporate balance sheets and extensive cross-ownership among major corporations. Structural social and labor market changes, including an aging workforce, population decline and traditional aversion to labor mobility may adversely affect Japan’s economic competitiveness and growth potential. The potential for natural disasters, such as earthquakes, volcanic eruptions, typhoons and tsunamis, could also have significant negative effects on Japan’s economy. As a result of the Fund’s investment in Japanese securities, the Fund’s NAV may be more volatile than the NAV of a more geographically diversified fund. If securities of issuers in Japan fall out of favor, it may cause the Fund to underperform other funds that do not focus their investments in Japan. 

Sector Risk. At times, the Fund may have a significant portion of its assets invested in securities of companies conducting business within one or more economic sectors, including the industrials and information technology sectors. Companies in the same sector may be similarly affected by economic, regulatory, political or market events or conditions, which may make the Fund more vulnerable to unfavorable developments in that sector than funds that invest more broadly. Generally, the more broadly the Fund invests, the more it spreads risk and potentially reduces the risks of loss and volatility. 

■ Industrials Sector. The Fund is more susceptible to the particular risks that may affect companies in the industrials sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the industrials sector are subject to certain risks, including changes in supply and demand for their specific product or service and for industrial sector products in general, including decline in demand for such products due to rapid technological developments and frequent new product introduction. Performance of such companies may be affected by factors including government regulation, world events, economic conditions and risks for environmental damage and product liability claims. 

■ Information Technology Sector. The Fund is more susceptible to the particular risks that may affect companies in the information technology sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the information technology sector are subject to certain risks, including the risk that new services, equipment or technologies will not be accepted by consumers and businesses or will become rapidly obsolete. Performance of such companies may be affected by factors including obtaining and protecting patents (or the failure to do so) and significant competitive pressures, including aggressive pricing of their products or services, new market entrants, competition for market share and short product cycles due to an accelerated rate of technological developments. Such competitive pressures may lead to limited earnings and/or falling profit margins. As a result, the value of their securities may fall or fail to rise. In addition, many information technology sector companies have limited operating histories and prices of these companies’ securities historically have been more volatile than other securities, especially over the short term. Some companies in the information technology sector are facing increased government and regulatory scrutiny and may be subject to adverse government or regulatory action, which could negatively impact the value of their securities. 

8 Prospectus 2022

Columbia Acorn International®

Summary of the Fund (continued)

Foreign Currency Risk. The performance of the Fund may be materially affected positively or negatively by foreign currency strength or weakness relative to the U.S. dollar, particularly if the Fund invests a significant percentage of its assets in foreign securities or other assets denominated in currencies other than the U.S. dollar. 

Issuer Risk. An issuer in which the Fund invests may perform poorly, and the value of its securities may therefore decline, which may negatively affect the Fund’s performance. Underperformance of an issuer may be caused by poor management decisions, competitive pressures, breakthroughs in technology, reliance on suppliers, labor problems or shortages, corporate restructurings, fraudulent disclosures, natural disasters, military confrontations and actions, war, terrorism, disease/virus outbreaks and epidemics or other events, conditions and factors. 

Growth Securities Risk. Growth securities typically trade at a higher multiple of earnings than other types of equity securities. Accordingly, the market values of growth securities may never reach their expected market value and may decline in price. In addition, growth securities, at times, may not perform as well as value securities or the stock market in general, and may be out of favor with investors for varying periods of time. 

Performance Information

The following bar chart and table show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. The bar chart shows how the Fund’s Class Inst share performance has varied for each full calendar year shown. The table below the bar chart compares the Fund’s returns for the periods shown with those of the MSCI ACWI ex USA SMID Cap Growth Index (Net), the Fund's primary benchmark, and those of the MSCI ACWI ex USA SMID Cap Index (Net), the Fund's secondary benchmark. The MSCI ACWI ex USA SMID Cap Growth Index (Net) captures mid- and small-cap securities exhibiting overall growth style characteristics across 22 developed market countries and 24 emerging market countries. The MSCI ACWI ex USA SMID Cap Index (Net) captures mid- and small-cap representation across 22 of 23 developed market countries (excluding the United States) and 24 emerging market countries. As of March 31, 2022, the MSCI ACWI ex USA SMID Cap Index (Net) had 5,541 constituents and covered approximately 28% of the free float-adjusted market capitalization in each country. 

The performance of one or more share classes shown in the Average Annual Total Returns table below includes the Fund’s Class Inst share returns (adjusted to reflect the higher class-related operating expenses of such classes, where applicable) for periods prior to the indicated inception date of such share classes. Except for differences in fees and expenses, all share classes of the Fund would have substantially similar annual returns because all share classes of the Fund invest in the same portfolio of securities. 

The after-tax returns shown in the Average Annual Total Returns table below are calculated using the highest historical individual U.S. federal marginal income tax rates in effect during the period indicated in the table and do not reflect the impact of state, local or foreign taxes. Your actual after-tax returns will depend on your personal tax situation and may differ from those shown in the table. In addition, the after-tax returns shown in the table do not apply to shares held in tax-advantaged accounts such as 401(k) plans or Individual Retirement Accounts (IRAs). The after-tax returns are shown only for Class Inst shares and will vary for other share classes. 

The Fund’s past performance (before and after taxes) is no guarantee of how the Fund will perform in the future. Updated performance information can be obtained by calling toll-free 800.345.6611 or visiting columbiathreadneedleus.com. 

Prospectus 2022 9

Columbia Acorn International®

Summary of the Fund (continued)

Year by Year Total Return (%) as of December 31 Each Year*	Best and Worst Quarterly Returns During the Period Shown in the Bar Chart
	Best	2nd Quarter 2020	27.28%
	Worst	1st Quarter 2020	-28.50%

* Year to Date return as of March 31, 2022: -18.81%

 Average Annual Total Returns After Applicable Sales Charges (for periods ended December 31, 2021)

	Share Class Inception Date	1 Year	5 Years	10 Years
Class Inst	09/23/1992
returns before taxes		12.89%	13.39%	9.91%
returns after taxes on distributions		8.95%	9.65%	7.59%
returns after taxes on distributions and sale of Fund shares		10.26%	10.03%	7.69%
Class A returns before taxes	10/16/2000	6.17%	11.78%	8.98%
Class Adv returns before taxes	11/08/2012	12.88%	13.39%	9.88%
Class C returns before taxes	10/16/2000	10.81%	12.26%	8.80%
Class Inst2 returns before taxes	08/02/2011	12.97%	13.46%	9.97%
Class Inst3 returns before taxes	11/08/2012	13.00%	13.51%	10.01%
Class R returns before taxes	08/02/2011	12.34%	12.83%	9.29%
MSCI ACWI ex USA SMID Cap Growth Index (Net) (reflects reinvested dividends net of withholding taxes but reflects no deductions for fees, expenses or other taxes)		8.51%	12.25%	9.34%
MSCI ACWI ex USA SMID Cap Index (Net) (reflects reinvested dividends net of withholding taxes but reflects no deductions for fees, expenses or other taxes)		10.16%	10.30%	8.63%

Fund Management

Investment Manager: Columbia Wanger Asset Management, LLC

Portfolio Management	Title	Role with Fund	Service with the Fund Since
Tae Han (Simon) Kim, CFA	Director of International Research, Portfolio Manager and Analyst	Co-Portfolio Manager since 2017	2011
Hans F. Stege	Portfolio Manager and Analyst	Co-Portfolio Manager since 2020	2017

10 Prospectus 2022

Columbia Acorn International®

Summary of the Fund (continued)

Purchase and Sale of Fund Shares

You may purchase or redeem shares of the Fund on any business day by contacting the Fund in the ways described below:

Online	Regular Mail	Express Mail	By Telephone
columbiathreadneedleus.com/investor/	Columbia Management Investment Services Corp. P.O. Box 219104 Kansas City, MO 64121-9104	Columbia Management Investment Services Corp. c/o DST Asset Manager Solutions, Inc. 430 W 7th Street, Suite 219104 Kansas City, MO 64105-1407	800.422.3737

You may purchase shares and receive redemption proceeds by electronic funds transfer, by check or by wire. If you maintain your account with a broker-dealer or other financial intermediary, you must contact that financial intermediary to buy, sell or exchange shares of the Fund through your account with the intermediary.

The minimum initial investment amounts for the share classes offered by the Fund are shown below:

Minimum Initial Investment

Class	Category of eligible account	For accounts other than Systematic Investment Plan accounts (as described in the Fund’s Prospectus)	For Systematic Investment Plan accounts
Classes A & C	All accounts other than IRAs	$2,000	$100
	IRAs	$1,000	$100
Classes Adv & Inst	All eligible accounts	$0, $1,000 or $2,000 depending upon the category of eligible investor	$100
Classes Inst2 & R	All eligible accounts	None	N/A
Class Inst3	All eligible accounts	$0, $1,000, $2,000 or $1 million depending upon the category of eligible investor	$100 (for certain eligible investors)

More information about these minimums can be found in the Buying, Selling and Exchanging Shares - Buying Shares section of the prospectus. There is no minimum additional investment for any share class.

Tax Information

The Fund normally distributes net investment income and net realized capital gains, if any, to shareholders. These distributions are generally taxable to you as ordinary income, qualified dividend income or capital gains, unless you are investing through a tax-advantaged account, such as a 401(k) plan or an IRA. If you are investing through a tax-advantaged account, you may be taxed upon withdrawals from that account.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase the Fund through a broker-dealer or other financial intermediary (such as a bank), the Fund and its related companies – including the Investment Manager, the Distributor and Columbia Management Investment Services Corp. (the Transfer Agent) – may pay the intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your financial advisor to recommend the Fund over another investment. These potential conflicts of interest may be heightened with respect to broker-dealers owned by Ameriprise Financial, Inc. (Ameriprise Financial) and/or its affiliates. Ask your financial advisor or visit your financial intermediary's website for more information.

Prospectus 2022 11

Columbia Acorn International®

More Information About the Fund

Investment Objective

Columbia Acorn International^® (the Fund) seeks long-term capital appreciation. The Fund’s investment objective is not a fundamental policy of the Fund and may be changed by the Fund’s Board of Trustees (the Board) without shareholder approval. There is no assurance the Fund’s objective will be achieved.

Principal Investment Strategies

Under normal circumstances, the Fund invests at least 75% of its net assets in foreign companies in developed markets (for example, Japan, Canada and the United Kingdom) and in emerging markets (for example, China, India and Brazil).

Under normal circumstances, the Fund invests a majority of its net assets in the common stock of small- and mid-sized companies with market capitalizations generally in the range of market capitalizations in the MSCI ACWI ex USA SMID Cap Growth Index (Net), the Fund's primary benchmark, (the Index) at the time of purchase (between $55.8 million and $29.7 billion as of March 31, 2022). The market capitalization range and composition of companies in the Index are subject to change. As such, the size of the companies in which the Fund invests may change. The Fund determines a company’s market capitalization at the time of investment. As long as a majority of its net assets are invested in companies within the Index, the Fund may continue to hold and make new investments in a security even if the company’s market capitalization grows beyond the market capitalization of the largest company within the Index or falls below the market capitalization of the smallest company within the Index. The Investment Manager from time to time emphasizes one or more sectors in selecting the Fund’s investments, including the industrials and information technology sectors.

Columbia Wanger Asset Management, LLC, the Fund's investment adviser (the Investment Manager), believes that stocks of small- and mid-sized companies, which generally are not as well known by financial analysts as larger companies, may offer higher return potential than stocks of larger companies. The Fund also may invest in larger-sized companies.

The Investment Manager typically seeks companies with:

■ A strong business franchise that offers growth potential.

■ Products and services in which the company has a competitive advantage.

■ A stock price the Investment Manager believes is reasonable relative to the assets and earning power of the company.

The Investment Manager may sell a portfolio holding if the security reaches the Investment Manager's price target, if the company has a deterioration of fundamentals, such as failing to meet key operating benchmarks, or if the Investment Manager believes other securities are more attractive. The Investment Manager also may sell a portfolio holding to fund redemptions.

Principal Risks

An investment in the Fund involves risks, including those described below, among others. There is no assurance that the Fund will achieve its investment objective and you may lose money. The value of the Fund’s holdings may decline, and the Fund’s net asset value (NAV) and share price may go down. An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Active Management Risk. The Fund is actively managed and its performance therefore will reflect, in part, the ability of the Investment Manager to select investments and to make investment decisions that will achieve the Fund’s investment objective. The Investment Manager’s active management of the Fund could cause the Fund to underperform its benchmark index and/or other funds with similar investment objectives and/or strategies.

Market Risk. The Fund may incur losses due to declines in the value of one or more securities in which it invests. These declines may be due to factors affecting a particular issuer, or the result of, among other things, political, regulatory, market, economic or social developments affecting the relevant market(s) more generally. In addition, turbulence in financial markets and reduced liquidity in equity, credit and/or fixed income markets may negatively

12 Prospectus 2022

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More Information About the Fund (continued)

affect many issuers, which could adversely affect the Fund’s ability to price or value hard-to-value assets in thinly traded and closed markets and could cause significant redemptions and operational challenges. Global economies and financial markets are increasingly interconnected, and conditions and events in one country, region or financial market may adversely impact issuers in a different country, region or financial market. These risks may be magnified if certain events or developments adversely interrupt the global supply chain; in these and other circumstances, such risks might affect companies worldwide. As a result, local, regional or global events such as terrorism, war, other conflicts, natural disasters, disease/virus outbreaks and epidemics or other public health issues, recessions, depressions or other events – or the potential for such events – could have a significant negative impact on global economic and market conditions.

The large-scale invasion of Ukraine by Russia in February 2022 has resulted in sanctions and market disruptions including declines in regional and global stock and commodity markets and significant devaluations of Russian currency. The extent and duration of the military action are impossible to predict but could be significant. Market disruption caused by the Russian military action, and any counter measures or responses thereto (including international sanctions, a downgrade in the country’s credit rating, purchasing and financing restrictions, boycotts, tariffs, changes in consumer or purchaser preferences, cyberattacks and espionage) could have severe adverse impacts on regional and/or global securities and commodities markets, including markets for oil and natural gas. These impacts may include reduced market liquidity, distress in credit markets, further disruption of global supply chains, increased risk of inflation, and limited access to investments in certain international markets and/or issuers. These developments and other related events could negatively impact Fund performance.

The pandemic caused by coronavirus disease 2019 and its variants (COVID-19) has resulted in, and may continue to result in, significant global economic and societal disruption and market volatility due to disruptions in market access, resource availability, facilities operations, imposition of tariffs, export controls and supply chain disruption, among others. Such disruptions may be caused, or exacerbated by, quarantines and travel restrictions, workforce displacement and loss in human and other resources. The uncertainty surrounding the magnitude, duration, reach, costs and effects of the global pandemic, as well as actions that have been or could be taken by governmental authorities or other third parties, present unknowns that are yet to unfold. The impacts, as well as the uncertainty over impacts to come, of COVID-19 – and any other infectious illness outbreaks, epidemics and pandemics that may arise in the future – could negatively affect global economies and markets in ways that cannot necessarily be foreseen. In addition, the impact of infectious illness outbreaks and epidemics in less developed countries may be greater due to generally less established healthcare systems, governments and financial markets. Public health crises caused by the COVID-19 outbreak may exacerbate other pre-existing political, social and economic risks in certain countries or globally. The disruptions caused by COVID-19 could prevent the Fund from executing advantageous investment decisions in a timely manner and negatively impact the Fund’s ability to achieve its investment objective. Any such events could have a significant adverse impact on the value and risk profile of the Fund.

Small- and Mid-Cap Company Securities Risk. Securities of small- and mid-cap companies can, in certain circumstances, have a higher potential for gains than securities of larger, more established companies but may also have more risk. For example, small- and mid-cap companies may be more vulnerable to market downturns and adverse business or economic events than larger companies because they may have more limited financial resources and business operations. Small- and mid-cap companies are also more likely than larger companies to have more limited product lines and operating histories and to depend on smaller and generally less experienced management teams. Securities of small- and mid-cap companies may trade less frequently and in smaller volumes and may be less liquid and fluctuate more sharply in value than securities of larger companies. When the Fund takes significant positions in small- and mid-cap companies with limited trading volumes, the liquidation of those positions, particularly in a distressed market, could be prolonged and result in Fund investment losses that would affect the value of your investment in the Fund. In addition, some small- and mid-cap companies may not be widely followed by the investment community, which can lower the demand for their stocks.

Foreign Securities Risk. Investments in or exposure to securities of foreign companies may involve heightened risks relative to investments in or exposure to securities of U.S. companies. For example, foreign markets can be extremely volatile. Foreign securities may also be less liquid, making them more difficult to trade, than securities of

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U.S. companies so that the Fund may, at times, be unable to sell foreign securities at desirable times or prices. Brokerage commissions, custodial costs and other fees are also generally higher for foreign securities. The Fund may have limited or no legal recourse in the event of default with respect to certain foreign securities, including those issued by foreign governments. In addition, foreign governments may impose withholding or other taxes on the Fund’s income, capital gains or proceeds from the disposition of foreign securities, which could reduce the Fund’s return on such securities. In some cases, such withholding or other taxes could potentially be confiscatory. Other risks include: possible delays in the settlement of transactions or in the payment of income; generally less publicly available information about foreign companies; the impact of economic, political, social, diplomatic or other conditions or events (including, for example, military confrontations and actions, war, other conflicts, terrorism and disease/virus outbreaks and epidemics), possible seizure, expropriation or nationalization of a company or its assets or the assets of a particular investor or category of investors; accounting, auditing and financial reporting standards that may be less comprehensive and stringent than those applicable to domestic companies; the imposition of economic and other sanctions against a particular foreign country, its nationals or industries or businesses within the country; and the generally less stringent standard of care to which local agents may be held in the local markets. In addition, it may be difficult to obtain reliable information about the securities and business operations of certain foreign issuers. Governments or trade groups may compel local agents to hold securities in designated depositories that are not subject to independent evaluation. The less developed a country’s securities market is, the greater the level of risks. Economic sanctions may be, and have been, imposed against certain countries, organizations, companies, entities and/or individuals. Economic sanctions and other similar governmental actions could, among other things, effectively restrict or eliminate the Fund’s ability to purchase or sell securities, and thus may make the Fund’s investments in such securities less liquid or more difficult to value. In addition, as a result of economic sanctions, the Fund may be forced to sell or otherwise dispose of investments at inopportune times or prices, which could result in losses to the Fund and increased transaction costs. These conditions may be in place for a substantial period of time and enacted with limited advance notice to the Fund. The risks posed by sanctions against a particular foreign country, its nationals or industries or businesses within the country may be heightened to the extent the Fund invests significantly in the affected country or region or in issuers from the affected country that depend on global markets. Additionally, investments in certain countries may subject the Fund to a number of tax rules, the application of which may be uncertain. Countries may amend or revise their existing tax laws, regulations and/or procedures in the future, possibly with retroactive effect. Changes in or uncertainties regarding the laws, regulations or procedures of a country could reduce the after-tax profits of the Fund, directly or indirectly, including by reducing the after-tax profits of companies located in such countries in which the Fund invests, or result in unexpected tax liabilities for the Fund.

Operational and Settlement Risks of Foreign Securities. The Fund’s foreign securities are generally held outside the United States in the primary market for the securities in the custody of certain eligible foreign banks and trust companies (“foreign sub-custodians”), as permitted under the Investment Company Act of 1940 (the 1940 Act). Settlement practices for foreign securities may differ from those in the United States. Some countries have limited governmental oversight and regulation of industry practices, stock exchanges, depositories, registrars, brokers and listed companies, which increases the risk of corruption and fraud and the possibility of losses to the Fund. In particular, under certain circumstances, foreign securities may settle on a delayed delivery basis, meaning that the Fund may be required to make payment for securities before the Fund has actually received delivery of the securities or deliver securities prior to the receipt of payment. Typically, in these cases, the Fund will receive evidence of ownership in accordance with the generally accepted settlement practices in the local market entitling the Fund to delivery or payment at a future date, but there is a risk that the security will not be delivered to the Fund or that payment will not be received, although the Fund and its foreign sub-custodians take reasonable precautions to mitigate this risk. Losses can also result from lost, stolen or counterfeit securities; defaults by brokers and banks; failures or defects of the settlement system; or poor and improper record keeping by registrars and issuers.

Share Blocking. Share blocking refers to a practice in certain foreign markets under which an issuer’s securities are blocked from trading at the custodian or sub-custodian level for a specified number of days before and, in certain instances, after a shareholder meeting where a vote of shareholders takes place. The blocking period can last up to several weeks. Share blocking may prevent the Fund from buying or selling securities during this period, because

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during the time shares are blocked, trades in such securities will not settle. It may be difficult or impossible to lift blocking restrictions, with the particular requirements varying widely by country. As a consequence of these restrictions, the Investment Manager, on behalf of the Fund, may abstain from voting proxies in markets that require share blocking.

Emerging Market Securities Risk. Securities issued by foreign governments or companies in emerging market countries, such as China, Russia and certain countries in Eastern Europe, the Middle East, Asia, Latin America or Africa, are more likely to have greater exposure to the risks of investing in foreign securities that are described in Foreign Securities Risk. In addition, emerging market countries are more likely to experience instability resulting, for example, from rapid changes or developments in social, political, economic or other conditions. Their economies are usually less mature and their securities markets are typically less developed with more limited trading activity (i.e., lower trading volumes and less liquidity) than more developed countries. Emerging market securities tend to be more volatile, and may be more susceptible to market manipulation, than securities in more developed markets. Many emerging market countries are heavily dependent on international trade and have fewer trading partners, which makes them more sensitive to world commodity prices and economic downturns in other countries. Some emerging market countries have a higher risk of currency devaluations, and some of these countries may experience periods of high inflation or rapid changes in inflation rates and may have hostile relations with other countries. Due to the differences in the nature and quality of financial information of issuers of emerging market securities, including auditing and financial reporting standards, financial information and disclosures about such issuers may be unavailable or, if made available, may be considerably less reliable than publicly available information about other foreign securities.

Operational and Settlement Risks of Securities in Emerging Markets. In addition to having less developed securities markets, banks in emerging markets that are eligible foreign sub-custodians may be recently organized, lack extensive operating experience or lack effective government oversight or regulation. In addition, there may be legal restrictions or limitations on the ability of the Fund to recover assets held in custody by a foreign sub-custodian in the event of the bankruptcy of the sub-custodian. Because settlement systems may be less organized than in developed markets and because delivery versus payment settlement may not be possible or reliable, there may be a greater risk that settlement may be delayed and that cash or securities of the Fund may be lost because of failures of or defects in the system, including fraud or corruption. Settlement systems in emerging markets also have a higher risk of failed trades.

Risks Related to Currencies and Corporate Actions in Emerging Markets. Risks related to currencies and corporate actions are also greater in emerging market countries than in developed countries. For example, some emerging market countries may have fixed or managed currencies that are not free-floating against the U.S. dollar. Further, certain currencies may not have an active trading market internationally, or countries may have varying exchange rates. Some emerging market countries have a higher risk of currency devaluations, and some of these countries may experience sustained periods of high inflation or rapid changes in inflation rates which can have negative effects on a country’s economy and securities markets. Corporate action procedures in emerging market countries may be less reliable and have limited or no involvement by the depositories and central banks. Lack of standard practices and payment systems can lead to significant delays in payment.

Risks Related to Corporate and Securities Laws in Emerging Markets. Securities laws in emerging markets may be relatively new and unsettled and, consequently, there is a risk of rapid and unpredictable change in laws regarding foreign investment, securities regulation, title to securities and shareholder rights. Accordingly, foreign investors may be adversely affected by new or amended laws and regulations. In addition, the systems of corporate governance to which issuers in certain emerging markets are subject may be less advanced than the systems to which issuers located in more developed countries are subject, and therefore, shareholders of such issuers may not receive many of the protections available to shareholders of issuers located in more developed countries. These risks may be heightened in China and Russia.

Liquidity and Trading Volume Risk. Due to market conditions, including uncertainty regarding the price of a security, it may be difficult for the Fund to buy or sell portfolio securities at a desirable time or price, which could result in investment losses. This risk of portfolio illiquidity is heightened with respect to small- and mid-cap securities, generally, and foreign small- and mid-cap securities in particular. The Fund may have to lower the selling price,

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liquidate other investments, or forego another, more appealing investment opportunity as a result of illiquidity in the markets. The Investment Manager will fair value in good faith any securities it deems to be illiquid under consistently applied procedures established by the Fund’s Board. Market conditions are always changing and vary by country and industry sector, and investing in international markets involves unique risks. Although it is difficult to accurately assess trends in trading volumes in foreign markets, a reduction in trading volumes poses challenges to the Fund. This is particularly so because the Fund focuses on small- and mid-cap companies that usually have lower trading volumes and often takes sizeable positions in portfolio companies. As a result of lower trading volumes, it may take longer to buy or sell securities, which can exacerbate the Fund’s exposure to volatile markets. The Fund may also be limited in its ability to execute favorable trades in portfolio securities in response to changes in share prices and fundamentals. If the Fund is forced to sell securities to meet redemption requests or other cash needs, or in the case of an event affecting liquidity in a particular market or markets, it may be forced to dispose of those securities under disadvantageous circumstances and at a loss. As the Fund grows in size or, conversely, if it faces significant redemption pressure, these considerations take on increasing significance and may adversely impact performance.

Geographic Focus Risk. The Fund may be particularly susceptible to risks related to economic, political, regulatory or other events or conditions affecting issuers and countries within the specific geographic regions in which the Fund invests. Currency devaluations could occur in countries that have not yet experienced currency devaluation to date, or could continue to occur in countries that have already experienced such devaluations. As a result, the Fund’s NAV may be more volatile than the NAV of a more geographically diversified fund.

■ Asia Pacific Region. A number of countries in the Asia Pacific region are considered underdeveloped or developing, including from a political, economic and/or social perspective, and may have relatively unstable governments and economies based on limited business, industries and/or natural resources or commodities. Events in any one country within the region may impact that country, other countries in the region or the region as a whole. As a result, events in the region will generally have a greater effect on the Fund than if the Fund were more geographically diversified in a region with more developed countries and economies. This could result in increased volatility in the value of the Fund’s investments and losses for the Fund. Continued growth of economies and securities markets in the region will require sustained economic and fiscal discipline, as well as continued commitment to governmental and regulatory reforms. Development also may be influenced by international economic conditions, including those in the United States and Japan, and by world demand for goods or natural resources produced in countries in the Asia Pacific region. Securities markets in the region are generally smaller and have a lower trading volume than those in the United States, which may result in the securities of some companies in the region being less liquid than U.S. or other foreign securities. Some currencies, inflation rates or interest rates in the Asia Pacific region are or can be volatile, and some countries in the region may restrict the flow of money in and out of the country. The risks described under “Emerging Market Securities Risk” and  “Foreign Securities Risk” may be more pronounced due to the Fund’s focus on investments in the region.

■ Europe. The Fund is particularly susceptible to risks related to economic, political, regulatory or other events or conditions, including acts of war or other conflicts in the region, affecting issuers and countries in Europe. Countries in Europe are often closely connected and interdependent, and events in one European country can have an adverse impact on, and potentially spread to, other European countries. Most developed countries in Western Europe are members of the EU, and many are also members of the European Economic and Monetary Union (EMU). European countries can be significantly affected by the tight fiscal and monetary controls that the EMU imposes on its members and with which candidates for EMU membership are required to comply. In addition, significant private and public sectors’ debt problems of a single EU country can pose economic risks to the EU as a whole. Unemployment in Europe has historically been higher than in the United States and public deficits are an ongoing concern in many European countries. As a result, the Fund’s NAV may be more volatile than the NAV of a more geographically diversified fund. If securities of issuers in Europe fall out of favor, it may cause the Fund to underperform other funds that do not focus their investments in this region of the world. The UK’s departure from the EU single market became effective January 1, 2021 with the end of the Brexit transition period and the post‐Brexit trade deal between the UK and EU taking effect on December 31, 2020. The impact of any partial or complete dissolution of the EU on the UK and European economies and the broader global economy could be significant, resulting in negative impacts on currency and financial markets generally, such as increased volatility

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and illiquidity, and potentially lower economic growth in markets in the UK, Europe and globally, which may adversely affect the value of your investment in the Fund. The impact of Brexit in the near‐ and long‐term is still unknown and could have additional adverse effects on economies, financial markets, currencies and asset valuations around the world. Any attempt by the Fund to hedge against or otherwise protect its portfolio or to profit from such circumstances may fail and, accordingly, an investment in the Fund could lose money over short or long periods. For more information on the risks associated with Brexit, see the Statement of Additional Information.

■ Japan. The Fund is particularly susceptible to the social, political, economic, regulatory and other conditions or events that may affect Japan’s economy. The Japanese economy is heavily dependent upon international trade, including, among other things, the export of finished goods and the import of oil and other commodities and raw materials. Because of its trade dependence, the Japanese economy is particularly exposed to the risks of currency fluctuation, foreign trade policy and regional and global economic disruption, including the risk of increased tariffs, embargoes, and other trade limitations or factors. Strained relationships between Japan and its neighboring countries, including China, South Korea and North Korea, based on historical grievances, territorial disputes, and defense concerns, may also cause uncertainty in Japanese markets. As a result, additional tariffs, other trade barriers, or boycotts may have an adverse impact on the Japanese economy. Japanese government policy has been characterized by economic regulation, intervention, protectionism and large government deficits. The Japanese economy is also challenged by an unstable financial services sector, highly leveraged corporate balance sheets and extensive cross-ownership among major corporations. Structural social and labor market changes, including an aging workforce, population decline and traditional aversion to labor mobility may adversely affect Japan’s economic competitiveness and growth potential. The potential for natural disasters, such as earthquakes, volcanic eruptions, typhoons and tsunamis, could also have significant negative effects on Japan’s economy. A significant portion of Japan's trade is conducted with developing nations in East and Southeast Asia and its economy can be affected by conditions and currency fluctuations in these and other countries. For a number of years, Japan’s economic growth rate has remained relatively low, and it may remain low in the future. Securities in Japan are denominated and quoted in yen. As a result, the value of the Fund's Japanese securities as measured in U.S. dollars may be affected by fluctuations in the value of the Japanese yen relative to the U.S. dollar. Securities traded on Japanese stock exchanges have exhibited significant volatility in recent years. As a result of the Fund’s investment in Japanese securities, the Fund’s NAV may be more volatile than the NAV of a more geographically diversified fund. If securities of issuers in Japan fall out of favor, it may cause the Fund to underperform other funds that do not focus their investments in Japan.

Sector Risk. At times, the Fund may have a significant portion of its assets invested in securities of companies conducting business within one or more economic sectors, including the industrials and information technology sectors. Companies in the same sector may be similarly affected by economic, regulatory, political or market events or conditions, which may make the Fund more vulnerable to unfavorable developments in that sector than funds that invest more broadly. Generally, the more broadly the Fund invests, the more it spreads risk and potentially reduces the risks of loss and volatility.

■ Industrials Sector. The Fund is more susceptible to the particular risks that may affect companies in the industrials sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the industrials sector are subject to certain risks, including changes in supply and demand for their specific product or service and for industrial sector products in general, including decline in demand for such products due to rapid technological developments and frequent new product introduction. Performance of such companies may be affected by factors including government regulation, world events, economic conditions and risks for environmental damage and product liability claims.

■ Information Technology Sector. The Fund is more susceptible to the particular risks that may affect companies in the information technology sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the information technology sector are subject to certain risks, including the risk that new services, equipment or technologies will not be accepted by consumers and businesses or will become rapidly obsolete. Performance of such companies may be affected by factors including obtaining and protecting patents (or the failure to do so) and significant competitive pressures, including aggressive pricing of their products or services, new market entrants, competition for market share and short product cycles due to an accelerated rate of

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technological developments. Such competitive pressures may lead to limited earnings and/or falling profit margins. As a result, the value of their securities may fall or fail to rise. In addition, many information technology sector companies have limited operating histories and prices of these companies’ securities historically have been more volatile than other securities, especially over the short term. Some companies in the information technology sector are facing increased government and regulatory scrutiny and may be subject to adverse government or regulatory action, which could negatively impact the value of their securities.

Foreign Currency Risk. The performance of the Fund may be materially affected positively or negatively by foreign currency strength or weakness relative to the U.S. dollar, particularly if the Fund invests a significant percentage of its assets in foreign securities or other assets denominated in currencies other than the U.S. dollar. Currency rates in foreign countries may fluctuate significantly over short or long periods of time for a number of reasons, including changes in interest rates, imposition of currency controls and economic or political developments in the U.S. or abroad. The Fund may also incur currency conversion costs when converting foreign currencies into U.S. dollars and vice versa. Restrictions on currency trading may be imposed by foreign countries, which may adversely affect the value of your investment in the Fund. Even though the currencies of some countries may be pegged to the U.S. dollar, the conversion rate may be controlled by government regulation or intervention at levels significantly different than what would normally prevail in a free market. Significant revaluations of the U.S. dollar exchange rate of these currencies could cause substantial reductions in the Fund’s NAV.

Issuer Risk. An issuer in which the Fund invests may perform poorly, and the value of its securities may therefore decline, which may negatively affect the Fund’s performance. Underperformance of an issuer may be caused by poor management decisions, competitive pressures, breakthroughs in technology, reliance on suppliers, labor problems or shortages, corporate restructurings, fraudulent disclosures, natural disasters, military confrontations and actions, war, terrorism, disease/virus outbreaks and epidemics or other events, conditions and factors.

Growth Securities Risk. Growth securities typically trade at a higher multiple of earnings than other types of equity securities. Accordingly, the market values of growth securities may never reach their expected market value and may decline in price. In addition, growth securities, at times, may not perform as well as value securities or the stock market in general, and may be out of favor with investors for varying periods of time.

Additional Investment Strategies and Policies

This section describes certain investment strategies and policies that the Fund may utilize in pursuit of its investment objective and some additional factors and risks involved with investing in the Fund. For information about risks associated with changing levels of Fund distributions, see the SAI.

Changing the Fund’s Investment Objective and Policies

The Fund’s investment objective and non-fundamental investment policies (including its principal and additional investment strategies) can be changed by the Board without shareholder approval, but may require notice to shareholders in certain instances. The Fund’s fundamental investment policies, as identified in the Fund’s Statement of Additional Information (SAI), may be changed only with Board and shareholder approval in accordance with the voting requirements of the 1940 Act. For additional information about changing the Fund’s fundamental and non-fundamental investment policies, see the SAI.

Investment Guidelines

As a general matter, and except as specifically described in the discussion of the Fund's principal investment strategies in this prospectus, whenever an investment policy or limitation states a percentage of the Fund's assets that may be invested in any security or other asset or sets forth a policy regarding an investment standard, compliance with that percentage limitation or standard will be determined based on the characteristics of a company at the time of initial purchase, and subsequent changes in a characteristic are not taken into account.

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Holding Other Kinds of Investments

The Fund may hold other investments that are not part of its principal investment strategies. These investments and their risks are described below and/or in the SAI. The Fund may choose not to invest in certain securities described in this prospectus and in the SAI, although it has the ability to do so. Information on the Fund’s holdings can be found in the Fund’s shareholder reports or by visiting columbiathreadneedleus.com.

Transactions in Derivatives

The Fund may enter into derivative transactions or otherwise have exposure to derivative transactions through underlying investments. The Fund expects to enter into such transactions primarily in the form of stock index futures in order to obtain exposure to the overall sector of the market represented by a particular stock index or to invest the Fund’s uninvested cash balances in a manner that the Investment Manager believes aligns more closely with the Fund’s investment strategy than simply holding short-term fixed income investments or cash equivalents (known as cash equitization). Derivatives are financial contracts whose values are, for example, based on (or “derived” from) traditional securities (such as a stock or bond), assets (such as a commodity like gold or a foreign currency), reference rates (such as the Secured Overnight Financing Rate (commonly known as SOFR) or the London Interbank Offered Rate (commonly known as LIBOR)) or market indices (such as the Standard & Poor's (S&P) 500^® Index). The use of derivatives is a highly specialized activity which involves investment techniques and risks different from those associated with ordinary portfolio securities transactions. Derivatives involve special risks and may result in losses or may limit the Fund's potential gain from favorable market movements. Derivative strategies typically expose the Fund to gains and losses in excess of the amount actually invested in the derivative. This characteristic of a derivative (known as "leverage") may exaggerate a loss, potentially causing the Fund to lose more money than it would have lost had it invested in the underlying security or other asset directly. The values of derivatives may move in unexpected ways, especially in unusual (including distressed) market conditions, and may result in increased volatility in the value of the derivative and/or the Fund’s shares, among other consequences. The use of derivatives may also increase the amount of taxes payable by shareholders holding shares in a taxable account. Other risks arise from the Fund's potential inability to terminate or to sell derivative positions. A liquid secondary market may not always exist for the Fund's derivative positions at times when the Fund might wish to terminate or to sell such positions. Over-the-counter instruments (investments not traded on an exchange) may be illiquid, and transactions in derivatives traded in the over-the-counter market are subject to the risk that the other party will not meet its obligations. The use of derivatives also involves the risks of mispricing or improper valuation and that changes in the value of the derivative may not correlate perfectly with the underlying security, asset, reference rate or index. The Fund also may not be able to find a suitable derivative transaction counterparty, and thus may be unable to engage in derivative transactions when it is deemed favorable to do so, or at all. U.S. federal legislation has been enacted that provides for new clearing, margin, reporting and registration requirements for participants in the derivatives market. These changes could restrict and/or impose significant costs or other burdens upon the Fund’s participation in derivatives transactions. The U.S. government and the European Union (and some other jurisdictions) have enacted regulations and similar requirements that prescribe clearing, margin, reporting and registration requirements for participants in the derivatives market. These requirements are evolving and their ultimate impact on the Fund remains unclear but such impact could include restricting and/or imposing significant costs or other burdens upon the Fund’s participation in derivatives transactions. Additionally, in October 2020, the SEC adopted new regulations governing the use of derivatives by registered investment companies. Once effective, Rule 18f-4 will, among other things, require funds that invest in derivative instruments beyond a specified limited amount to apply a value-at-risk based limit to their use of certain derivative instruments and establish a comprehensive derivatives risk management program. A fund that uses derivative instruments in a limited amount will not be subject to the full requirements of Rule 18f-4. Compliance with Rule 18f-4 will not be required until August 2022. Rule 18f-4 could have an adverse impact on the Fund’s performance and ability to implement its investment strategies as it has historically. For more information on the risks of derivative investments and strategies, see the SAI.

LIBOR Phase-Out Risk. Many derivatives and other financial instruments utilize or are permitted to utilize a floating interest rate based on LIBOR. On July 27, 2017, the United Kingdom's Financial Conduct Authority (FCA) announced its intention to phase out the use of LIBOR by the end of 2021. The FCA and the ICE Benchmark Administration have since announced that a majority of U.S. dollar LIBOR settings will cease publication after June 30, 2023. A subset of

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non-U.S. dollar LIBOR settings are continuing to be published on a “synthetic” basis and it is possible that a subset of U.S. dollar LIBOR settings will also be published after June 30, 2023 on a “synthetic” basis. Any such publications are, or would be considered, non-representative of the underlying market. Uncertainty related to the liquidity impact of changes in reference rates, and how to appropriately adjust these rates at the time of transition, poses risks for the Fund. It is difficult to predict the full impact of the transition away from LIBOR on the Fund until new reference rates and fallbacks for both legacy and new products, instruments and contracts are commercially accepted and market practices become more settled. The Investment Manager monitors the Fund's LIBOR exposure risks, including the extent to which any derivative and/or debt investments allow for the utilization of alternative rate(s), such as the Secured Overnight Financing Rate (SOFR), which the U.S. Federal Reserve is promoting as the alternative reference rate to LIBOR.

Affiliated Fund Investing

The Investment Manager and its affiliate, Columbia Management Investment Advisers, LLC (Columbia Management), each serves as investment adviser to mutual funds and ETFs using the Columbia brand (Columbia Funds), including mutual funds that are structured as “fund-of-funds”, and provides asset-allocation services to (i) shareholders by investing in shares of other Columbia Funds, which may include the Fund (collectively referred to in this section as Underlying Funds), and (ii) discretionary managed accounts (collectively referred to as affiliated products) that invest exclusively in Underlying Funds. These affiliated products, individually or collectively, may own a significant percentage of the outstanding shares of one or more Underlying Funds, and the Investment Manager and Columbia Management seek to balance potential conflicts of interest between the affiliated products and the Underlying Funds in which they invest. The affiliated products’ investment in the Underlying Funds may have the effect of creating economies of scale, possibly resulting in lower expense ratios for the Underlying Funds, because the affiliated products may own substantial portions of the shares of Underlying Funds. However, redemption of Underlying Fund shares by one or more affiliated products could cause the expense ratio of the Underlying Fund to increase, as its fixed costs would be spread over a smaller asset base. Because of large positions of certain affiliated products, the Underlying Funds may experience relatively large inflows and outflows of cash due to affiliated products’ purchases and sales of Underlying Fund shares. Although the Investment Manager or Columbia Management may seek to minimize the impact of these transactions where possible, for example, by structuring them over a reasonable period of time or through other measures, Underlying Funds may experience increased expenses as they buy and sell portfolio securities to manage the cash flow effect related to these transactions. Further, when the Investment Manager or Columbia Management structures transactions over a reasonable period of time in order to manage the potential impact of the buy and sell decisions for the affiliated products, those affiliated products, including funds-of-funds, may pay more or less (for purchase activity), or receive more or less (for redemption activity), for shares of the Underlying Funds than if the transactions were executed in one transaction. In addition, substantial redemptions by affiliated products within a short period of time could require the Underlying Fund to liquidate positions more rapidly than would otherwise be desirable, which may have the effect of reducing or eliminating potential gain or causing it to realize a loss. In order to meet such redemptions, the Underlying Fund may be forced to sell its liquid (or more liquid) positions, leaving the Underlying Fund holding, post-redemption, a relatively larger position in illiquid investments (i.e., any investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without the sale or disposition significantly changing the market value of the investment) or less liquid securities. Substantial redemptions may also adversely affect the ability of the Underlying Fund to implement its investment strategy. The Investment Manager or Columbia Management also has a conflict of interest in determining the allocation of affiliated products’ assets among the Underlying Funds, as it earns different fees from the various Underlying Funds.

Investing in Money Market Funds

The Fund may invest cash, including cash collateral received in connection with its securities lending program, in shares of money market funds, including funds advised by affiliates of the Investment Manager. These funds are not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency. The Fund and its shareholders indirectly bear a portion of the expenses of any money market fund or other fund in which the Fund may invest.

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Lending of Portfolio Securities

The Fund may lend portfolio securities to broker-dealers or other financial intermediaries on a fully collateralized basis in order to earn additional income. The Fund may lose money from securities lending if, for example, the borrower does not return a loaned security and the proceeds from sale of the collateral are not sufficient to replace the borrowed security. The Fund invests collateral in a government money market fund.

Investing Defensively

The Fund may from time to time take temporary defensive investment positions that are inconsistent with the Fund’s principal investment strategies in attempting to respond to adverse market, economic, political, social or other conditions. These investment positions may include, without limitation, investing some or all of its assets in money market instruments or shares of affiliated or unaffiliated money market funds or holding some or all of its assets in cash or cash equivalents. The Fund may take such defensive positions for as long a period as the Investment Manager deems necessary. During these times, the Investment Manager may make frequent portfolio changes, which could result in increased trading expenses and taxes, and decreased Fund performance.

Portfolio Holdings Disclosure

A description of the Fund’s policies and procedures with respect to the disclosure of Fund portfolio securities is available in the SAI. The Fund discloses its portfolio holdings on the Columbia Funds’ website, columbiathreadneedleus.com, as described below. Once posted, the portfolio holdings information will remain available on the website until at least the date on which such Fund files a Form N-CSR or publicly available Form N-PORT (forms filed with the SEC that include portfolio holdings information) for the period that includes the date as of which the information is current.

The Fund considers changes in its portfolio holdings to be confidential information. Consequently, Fund policy generally permits the disclosure of portfolio holdings information only after a certain amount of time has passed. The Fund’s complete portfolio holdings are disclosed approximately 30 to 40 days after each month-end. The top 15 holdings may be available sooner, approximately 15 calendar days after each month-end. Purchases and sales of portfolio securities can take place at any time, so the portfolio holdings information available on the website may not always be current.

Cybersecurity

The Fund, like all companies, may be susceptible to operational and information security risks, including the risk of cyber attacks or failures. As a result, the Fund or its service providers, or the issuers of securities in which the Fund invests, may experience disruptions in business operations that may potentially result in financial losses, the inability of the Fund or Fund shareholders to transact business, violations of applicable privacy and other laws, regulatory fines, penalties, reputational damage, reimbursement or other compensation costs, and/or additional compliance costs. The Fund and its shareholders could be negatively impacted as a result. See the discussion of Cybersecurity Breaches and Technology and Related Systems Failure Risk in the SAI for further information.

Use of Benchmarks

Benchmarks are indices that provide some comparative guidance in assessing the Fund’s performance. The Investment Manager selects the benchmarks it believes provide meaningful comparisons for each Fund. However, there may be different or additional indices that more closely reflect the market sectors in which the Fund invests. The Fund’s benchmarks may change from time to time. The benchmarks included in this prospectus are intended only as guideposts for your assessment of the Fund’s performance.

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 FUNDamentals

Portfolio Holdings Versus the Benchmarks

The Fund does not limit its investments to the securities within its benchmarks, and accordingly the Fund's holdings may diverge significantly from those of the benchmarks selected by the Investment Manager. In addition, the Fund may invest in securities outside the industry and geographic sectors represented in its benchmarks. The Fund's weightings in individual securities, and in industry and geographic sectors, may also vary considerably from those of its benchmarks.

eDelivery and Mailings to Households

In order to reduce shareholder expenses, the Fund may mail only one copy of the Fund’s prospectus and each annual and semiannual report to those addresses shared by two or more accounts. If you wish to receive separate copies of these documents, call 800.345.6611 or, if your shares are held through a financial intermediary, contact your intermediary directly. Additionally, you may elect to enroll in eDelivery to receive electronic versions of these documents, as well as quarterly statements and supplements, by logging into your account at columbiathreadneedleus.com/investor/.

Additional Information on Portfolio Turnover

A mutual fund that replaces, or turns over, more than 100% of its investments in a year may be considered to have a high portfolio turnover rate. A high portfolio turnover rate can generate larger distributions of short-term capital gains to shareholders, which for individuals are generally taxable at higher rates than long-term capital gains for U.S. federal income tax purposes. Also, a high portfolio turnover rate can mean higher brokerage commissions and other transaction costs, which could reduce a fund’s returns. In general, the greater the volume of buying and selling by a fund, the greater the impact that brokerage commissions and other transaction costs will have on its returns. The Fund may sell securities regardless of how long they’ve been held. See the Financial Highlights section of this prospectus for the Fund's portfolio turnover rates for the past five years.

Cash Flows

The timing and magnitude of cash inflows from investors buying Fund shares could prevent the Fund from always being fully invested. Conversely, the timing and magnitude of cash outflows to shareholders redeeming Fund shares could require the Fund to sell portfolio securities at less than opportune times or to hold ready reserves of uninvested cash in amounts larger than might otherwise be the case to meet shareholder redemptions. Either situation could adversely impact the Fund’s performance.

Understanding Annual Fund Operating Expenses

The Fund’s annual operating expenses, as presented in the Annual Fund Operating Expenses table in the Fees and Expenses of the Fund section of this prospectus, generally are based on expenses incurred during the Fund’s most recently completed fiscal year, may vary by share class and are expressed as a percentage (expense ratio) of the Fund’s average net assets during that fiscal year. The expense ratios reflect the Fund’s fee arrangements as of the date of this prospectus and, unless indicated otherwise, are based on expenses incurred during the Fund’s most recent fiscal year. The Fund’s assets will fluctuate, but unless indicated otherwise in the Annual Fund Operating Expenses table, no adjustments have been or will be made to the expense ratios to reflect any differences in the Fund’s average net assets between the most recently completed fiscal year and the date of this prospectus or a later date. In general, the Fund’s expense ratios will increase as its net assets decrease, such that the Fund’s actual expense ratios may be higher than the expense ratios presented in the Annual Fund Operating Expenses table if assets fall. Any commitment by the Investment Manager and/or its affiliates to waive fees and/or cap (reimburse) expenses is expected, in part, to limit the impact of any increase in the Fund’s expense ratios that would otherwise result because of a decrease in the Fund’s assets in the current fiscal year. The Fund’s annual operating expenses are comprised of (i) investment management fees, (ii) distribution and/or service fees, and (iii) other expenses.

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Management fees do not vary by class, but distribution and/or service fees and other expenses may vary by class. Please see Fee Waiver/Expense Reimbursement Arrangements below for information about commitments made by the Investment Manager and/or its affiliates during the performance period covered by this prospectus.

 FUNDamentals

Other Expenses

“Other expenses” consist of the fees the Fund pays to its administrator, custodian, transfer agent, auditors, lawyers and trustees, costs relating to compliance and miscellaneous expenses. Generally, these expenses are allocated on a pro rata basis across all share classes. These expenses include certain sub-transfer agency and shareholder servicing fees. Transfer agency fees and certain shareholder servicing fees, however, are class specific. They differ by share class because the shareholder services provided to each share class may be different. Accordingly, the differences in “other expenses” among share classes are primarily the result of the different transfer agency and shareholder servicing fees applicable to each share class. For more information on these fees, see Choosing a Share Class — Financial Intermediary Compensation.

Fee Waiver/Expense Reimbursement Arrangements

The Investment Manager has contractually agreed to waive fees and reimburse certain expenses of the Fund through April 30, 2023, so that ordinary operating expenses (excluding transaction costs and certain other investment-related expenses, interest and fees on borrowings, and expenses associated with the Fund’s investment in other investment companies, if any) do not exceed the annual rates of:

Columbia Acorn International
Class A	1.23%
Class Adv	0.98%
Class C	1.98%
Class Inst	0.98%
Class Inst2	0.92%
Class Inst3	0.88%
Class R	1.48%

This arrangement may only be amended or terminated with approval from the Fund’s Board of Trustees and the Investment Manager.

The Transfer Agent has contractually agreed to waive a portion of the fees payable by the Fund such that through April 30, 2023, fees paid by the Fund to the Transfer Agent do not exceed the annual rates of (i) 0.04% of the average daily net assets of Class Inst2 shares of the Fund and (ii) 0.00% of the average daily net assets of Class Inst3 shares of the Fund unless sooner terminated at the sole discretion of the Fund's Board of Trustees.

Effect of Fee Waivers and/or Expense Reimbursements on Past Performance. The Fund’s returns shown in the Performance Information section of this prospectus reflect the effect of fee waivers and/or reimbursements of Fund expenses by the Investment Manager and/or its affiliates that were in place during the performance period shown in the Performance Information section of this prospectus. Without such fee waivers/expense reimbursements, the Fund’s returns might have been lower.

Board of Trustees

The Fund is governed by the Board. More than 75% of the Fund's Trustees are independent (Independent Trustees), meaning that they are not “interested persons” of the Fund, as defined in the 1940 Act. The Independent Trustees bring backgrounds in business and academia to their task of working with the Fund's officers to establish the Fund's

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policies and oversee its activities. Among the Trustees' responsibilities are: selecting the investment adviser for the Fund; approving the advisory agreement; reviewing other contracts; approving investment policies; monitoring Fund operations, performance, compliance and costs; and nominating or selecting new Trustees.

Each Trustee serves the Fund for an indefinite term until his or her retirement, resignation, death or removal in accordance with the organizational documents of Columbia Acorn Trust (the Trust). The Trust's Bylaws generally require that Trustees retire at the end of the calendar year in which they attain the age of 75 years. The last meeting to elect Trustees was held on February 27, 2015. Any Trustee may be removed at a shareholders' meeting by a vote representing two-thirds of the net asset value of all shares of the Columbia Acorn family of funds (Columbia Acorn Funds). The mailing address for the Trustees and officers is 71 S. Wacker Drive, Suite 2500, Chicago, Illinois 60606.

For more detailed information about the Board, please refer to the SAI.

Primary Service Provider Contracts

The Fund enters into contractual arrangements (Service Provider Contracts) with various parties, including, among others, the Investment Manager, the Distributor, the Transfer Agent and the Fund’s custodian. The Fund’s Service Provider Contracts are solely among the parties thereto. Shareholders are not parties to, or intended to be third-party beneficiaries of, any Service Provider Contracts. Further, this prospectus, the SAI and any Service Provider Contracts are not intended to give rise to any agreement, duty, special relationship or other obligation between the Fund and any investor, or give rise to any contractual, tort or other rights in any individual shareholder, group of shareholders or other person, including any right to assert a fiduciary or other duty, enforce the Service Provider Contracts against the parties or to seek any remedy thereunder, either directly or on behalf of the Fund. Nothing in the previous sentence should be read to suggest any waiver of any rights under federal or state securities laws.

The Investment Manager, which also serves as the Fund's administrator (the Administrator), Columbia Management, which serves as the Fund's sub-administrator pursuant to an agreement with the Investment Manager (the Sub-Administrator), the Distributor, and the Transfer Agent are all affiliates of Ameriprise Financial. They and their affiliates currently provide key services, including investment advisory, administration, distribution, shareholder servicing and transfer agency services, to the Fund and various other funds, including the Columbia Funds, and are paid for providing these services. These service relationships are described below.

The Investment Manager

Columbia Wanger Asset Management, LLC is located at 71 S. Wacker Drive, Suite 2500, Chicago, Illinois 60606. As of March 31, 2022, the Investment Manager had assets under management of approximately $9.2 billion. The Investment Manager is a registered investment adviser and wholly-owned subsidiary of Columbia Management, which is a wholly-owned subsidiary of Ameriprise Financial. In addition to serving as an investment adviser to mutual funds, the Investment Manager acts as an investment manager for other private funds and institutional accounts.

Subject to oversight by the Board, the Investment Manager manages the day-to-day operations of the Fund, determining what securities and other investments the Fund should buy or sell and executing portfolio transactions. The Investment Manager may use the research and other capabilities of its affiliates and third parties in managing the Fund’s investments.

The Fund pays the Investment Manager a fee for its investment advisory services. The fee is calculated as a percentage of the daily net assets of the Fund and is paid monthly. For the Fund’s most recent fiscal year, aggregate fees paid to the Investment Manager by the Fund amounted to 0.79% of average daily net assets of the Fund, before any applicable reimbursements.

A discussion regarding the basis for the Board’s approval of the renewal of the Fund’s investment management services agreement with the Investment Manager is available in the Fund’s annual report to shareholders for the fiscal year ended December 31, 2021.

The Investment Manager and its investment advisory affiliates, including Columbia Management (Affiliates), around the world may coordinate in providing services to their clients. From time to time, the Investment Manager may engage its Affiliates to provide a variety of services such as investment research, investment monitoring, trading, and discretionary investment management (including portfolio management and proxy voting) to certain accounts

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managed by the Investment Manager, including the Fund. These Affiliates will provide services to the Fund and other accounts of the Investment Manager either pursuant to delegation agreements, personnel-sharing agreements or similar inter-company or other arrangements or relationships and the Fund will pay no additional fees and expenses as a result of any such arrangements or relationships. These Affiliates, like the Investment Manager, are direct or indirect subsidiaries of Ameriprise Financial and are registered with the appropriate respective regulators and, where required, the SEC and the Commodity Futures Trading Commission in the United States.

Pursuant to some of these arrangements or relationships, certain personnel of Columbia Management and other Affiliates may serve as “associated persons” or officers of the Investment Manager and, in this capacity, subject to the oversight and supervision of the Investment Manager and consistent with the investment objectives, policies and limitations set forth in this prospectus and the Fund's SAI, and with the Investment Manager’s and the Funds’ compliance policies and procedures, may provide such services to the Fund.

Portfolio Managers

Information about the portfolio managers primarily responsible for overseeing the Fund’s investments is shown below. The SAI provides additional information about the portfolio managers, including information relating to compensation, other accounts managed by the portfolio managers, and ownership by the portfolio managers of Fund shares.

Portfolio Management	Title	Role with Fund	Service with the Fund Since
Tae Han (Simon) Kim, CFA	Director of International Research, Portfolio Manager and Analyst	Co-Portfolio Manager since 2017	2011
Hans F. Stege	Portfolio Manager and Analyst	Co-Portfolio Manager since 2020	2017

Mr. Kim has been associated with the Investment Manager as an investment professional since 2011, and has served as a Vice President of the Trust since March 2018. Mr. Kim began his investment career in 2007 and earned a B.A. from Boston College and an M.B.A from the University of Oxford.

Mr. Stege has been associated with the Investment Manager or its predecessors as an investment professional since 2017 and has been a Vice President of the Trust since March 2020. Prior to joining the Investment Manager, Mr. Stege was a partner and research analyst at another investment firm, and also worked as a senior analyst for an energy consulting firm. Mr. Stege began his investment career in 2014 and earned a B.A. from Dartmouth College and an M.B.A. from the University of Chicago Booth School of Business.

The Administrator

Columbia Wanger Asset Management, LLC is responsible for overseeing the administrative operations of the Fund, including the general supervision of the Fund’s operations, coordination of the Fund’s service providers, and the provision of office facilities and related clerical and administrative services. The Administrator retains the Sub-Administrator to perform many of these services (including fund accounting), and pays a fee for the services of the Sub-Administrator. The Fund pays the Administrator a fee for its services, plus certain out-of-pocket expenses. The fee is calculated as an annual percentage of the Trust’s aggregate average daily net assets and is paid monthly, as follows:

Annual Administration Fee, as a % of Aggregate Daily Net Assets of the Trust:
Up to $8 billion	0.050%
$8 billion to $16 billion	0.040%
$16 billion to $35 billion	0.030%
$35 billion to $45 billion	0.025%
$45 billion and over	0.015%

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The Distributor

Shares of the Fund are distributed by Columbia Management Investment Distributors, Inc., which is located at 290 Congress Street, Boston, MA 02210. The Distributor is a registered broker-dealer and an indirect, wholly-owned subsidiary of Ameriprise Financial. The Distributor and its affiliates may pay commissions, distribution and service fees and/or other compensation to entities, including Ameriprise Financial affiliates, for selling shares and providing services to investors.

The Transfer Agent

Columbia Management Investment Services Corp. is a registered transfer agent and wholly-owned subsidiary of Ameriprise Financial. The Transfer Agent is located at 290 Congress Street, Boston, MA 02210, and its responsibilities include processing purchases, redemptions and exchanges of Fund shares, calculating and paying distributions, maintaining shareholder records, preparing account statements and providing customer service. The Transfer Agent has engaged DST Asset Manager Solutions, Inc. to provide various shareholder or “sub-transfer agency” services. In addition, the Transfer Agent enters into agreements with various financial intermediaries through which you may hold Fund shares, pursuant to which the Transfer Agent pays these financial intermediaries for providing certain shareholder services. Depending on the type of account, the Fund pays the Transfer Agent a per account fee for each open account and compensates the Transfer Agent for certain out-of-pocket expenses, including certain payments to financial intermediaries through which shares are held. In addition, subject to certain limitations, the Fund compensates the Transfer Agent for payments made to financial intermediaries for the shareholder services that the intermediaries provide, in amounts that vary by share class and with the type of intermediary and the type of shareholder services provided. The Transfer Agent is contractually obligated to oversee such intermediaries for the purpose of reasonably assuring their compliance with applicable law and the terms of their agreements to provide the shareholder services. For more information about Shareholder Services fees, see Choosing a Share Class — Financial Intermediary Compensation.

Other Roles and Relationships of Ameriprise Financial and its Affiliates — Certain Conflicts of Interest

This section describes certain actual and potential conflicts of interest that arise from the financial services activities of Ameriprise Financial and its affiliates. Ameriprise Financial is a major financial services company, engaged in a broad range of financial activities beyond the fund-related activities of the Investment Manager, including: insurance, broker-dealer (sales and trading), asset management and financial services. As a consequence of these activities, Ameriprise Financial or its affiliates may have interests arising from their other business lines that conflict with the interests of the Fund. These activities may also, from time to time, place certain investment constraints on the management of the Fund that might not otherwise arise.

As described in More Information About the Fund - Primary Service Provider Contracts, the Investment Manager, Administrator, Sub-Administrator, Distributor and Transfer Agent are all affiliates of Ameriprise Financial. In addition to the services that they provide to the Fund, they also provide substantially similar services (for which they are compensated) to other clients and customers, including the Columbia Funds. Ameriprise Financial and its other affiliates may also provide services (for which they are compensated) to the Fund, other Columbia Funds or other clients and customers.

Examples of activities that could lead to conflicts of interest and/or impose limitations that could affect the Fund include the following:

■ the Investment Manager and other Ameriprise Financial affiliates may receive compensation and other benefits related to the management/administration of the Fund and the other Columbia Funds and the sale of their shares;

■ there may be competition for limited investment opportunities that must be allocated among the Fund, the other Columbia Funds and other clients and customers of the Investment Manager (which can include affiliates of the Investment Manager) that may have the same or similar investment objectives as the Fund;

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■ management of the Fund may diverge from other Columbia Funds or other clients and customers of the Investment Manager or Ameriprise Financial affiliates, for example, advice given to the Fund may differ from, or conflict with, advice given to other funds or accounts;

■ there may be regulatory or investment restrictions imposed on the investment activities of the Investment Manager arising from the activities or holdings of other Columbia Funds or other clients or customers of the Investment Manager or Ameriprise Financial and its affiliates, for example, caps on the aggregate amount of certain types of investments or in holdings of particular portfolio companies that may be made by affiliated entities, including the Fund;

■ Ameriprise Financial or its affiliates may have potentially conflicting relationships with companies and other entities in which the Fund invests; and

■ there may be regulatory and other restrictions relating to the sharing of information between Ameriprise Financial and its affiliates, including the Investment Manager, for example, if an affiliated entity were in possession of non-public information, the Investment Manager might be prohibited by law from using that information in connection with the management of the Fund.

The Investment Manager and Ameriprise Financial have adopted various policies and procedures that are intended to identify, monitor and address conflicts of interest. However, there is no absolute assurance that these policies, procedures and disclosures will be effective.

Additional information about Ameriprise Financial and the types of conflicts of interest and other matters referenced above is set forth in the Investment Advisory and Other Services – Other Roles and Relationships of Ameriprise Financial and Affiliates – Certain Conflicts of Interest section of the SAI. Investors in the Fund should carefully review these disclosures and consult with their financial advisor if they have any questions.

Certain Legal Matters

Ameriprise Financial and certain of its affiliates are involved in the normal course of business in legal proceedings which include regulatory inquiries, arbitration and litigation, including class actions concerning matters arising in connection with the conduct of its activities as a diversified financial services firm. Ameriprise Financial believes that the Fund is not currently the subject of, and that neither Ameriprise Financial nor any of its affiliates are the subject of, any pending legal, arbitration or regulatory proceedings that are likely to have a material adverse effect on the Fund or the ability of Ameriprise Financial or its affiliates to perform under their contracts with the Fund. Information regarding certain pending and settled legal proceedings may be found in the Fund’s shareholder reports and in the SAI. Additionally, Ameriprise Financial is required to make quarterly (10-Q), annual (10-K) and, as necessary, 8-K filings with the SEC on legal and regulatory matters that relate to Ameriprise Financial and its affiliates. Copies of these filings may be obtained by accessing the SEC website at sec.gov.

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The Funds

The Columbia Acorn Funds and the other Columbia Funds generally share the same policies and procedures for investor services, as described below. Together, the Fund and the other Columbia Acorn Funds, along with the Columbia Funds, are referred to herein as the Funds.

Funds Contact Information

Additional information about the Funds, including sales charges and other class features and policies, can be obtained, free of charge, at columbiathreadneedleus.com,* by calling toll-free 800.345.6611, or by writing (regular mail) to Columbia Management Investment Services Corp., P.O. Box 219104, Kansas City, MO 64121-9104 or (express mail) Columbia Management Investment Services Corp., c/o DST Asset Manager Solutions, Inc., 430 W 7^th Street, Ste 219104, Kansas City, MO 64105-1407.

* The website references in this prospectus are inactive links and information contained in or otherwise accessible through the referenced websites does not form a part of this prospectus.

 FUNDamentals

Financial Intermediaries

The term “financial intermediary” refers to the selling and servicing agents that are authorized to sell and/or service shares of the Funds. Financial intermediaries include broker-dealers and financial advisors as well as firms that employ broker-dealers and financial advisors, including, for example, brokerage firms, banks, investment advisers, third party administrators and other firms in the financial services industry.

Omnibus Accounts

The term “omnibus account” refers to a financial intermediary’s account with the Fund (held directly through the Transfer Agent) that represents the combined holdings of, and transactions in, Fund shares of one or more clients of the financial intermediary (beneficial Fund shareholders). Omnibus accounts are held in the name of the financial intermediaries and not in the name of the beneficial Fund shareholders invested in the Fund through omnibus accounts.

Retirement Plans and Omnibus Retirement Plans

The term “retirement plan” refers to retirement plans created under Sections 401(a), 401(k), 457 and 403(b) of the Internal Revenue Code of 1986, as amended (the Code), and non-qualified deferred compensation plans governed by Section 409A of the Code and similar plans, but does not refer to individual retirement plans, such as traditional IRAs and Roth IRAs. The term “omnibus retirement plan” refers to a retirement plan that has a plan-level or omnibus account with the Transfer Agent.

Networked Accounts

Networking, offered by the Depository Trust & Clearing Corporation’s Wealth Management Services (WMS), is the industry standard IT system for mutual fund account reconciliation and dividend processing.

Summary of Share Class Features

Each share class has its own investment eligibility criteria, cost structure and other features. You may not be eligible to invest in every share class. Your financial intermediary may not make every share class available or may cease to make available one or more share classes of the Fund. The share class you select through your financial intermediary may have higher fees and/or sales charges than other classes of shares available through other financial intermediaries. An investor transacting in a class of Fund shares without any front-end sales charge, contingent deferred sales charge (CDSC), or other asset-based fee for sales or distribution, such as a Rule 12b-1 fee, may be required to pay a commission to the financial intermediary for effecting such transactions. Each investor’s personal situation is different and you may wish to discuss with your financial intermediary the share classes the Fund offers, which share classes are available to you and which share class(es) is/are appropriate for you. In all instances, it is your responsibility to notify your financial intermediary or (for Direct-at-Fund Accounts, as

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defined below) the Fund at the time of purchase of any relationship or other facts that may qualify you for sales charge waivers or discounts. The Fund, the Distributor and the Transfer Agent do not provide investment advice or make recommendations regarding Fund share classes. Your financial intermediary may provide advice and recommendations to you, such as which share class(es) is/are appropriate for you.

When deciding which class of shares to buy, you should consider, among other things:

■ The amount you plan to invest.

■ How long you intend to remain invested in the Fund.

■ The fees (e.g., sales charge or “load”) and expenses for each share class.

■ Whether you may be eligible for a reduction or waiver of sales charges when you buy or sell shares.

 FUNDamentals

Front-End Sales Charge Calculation

The front-end sales charge is calculated as a percentage of the offering price.

■ The net asset value (NAV) per share is the price of a share calculated by the Fund every business day.

■ The offering price per share is the NAV per share plus any front-end sales charge (or load) that applies.

The dollar amount of any applicable front-end sales charge is the difference between the offering price of the shares you buy and the NAV of those shares. To determine the front-end sales charge you will pay when you buy Class A shares, the Fund will add the amount of your investment to the value of your account (and any other accounts eligible for aggregation of which you or your financial intermediary notifies the Fund) and base the sales charge on the aggregate amount. For information on account value aggregation, sales charge waivers and other important information, see Choosing a Share Class — Reductions/Waivers of Sales Charges.

 FUNDamentals

Contingent Deferred Sales Charge

A contingent deferred sales charge (CDSC) is a sales charge applied at the time you sell your shares, unlike a front-end sales charge that is applied at the time of purchase. A CDSC can vary based on the length of time that you have held your shares. A CDSC is applied to the NAV at the time of your purchase or sale, whichever is lower, and will not be applied to any shares you receive through Fund distribution reinvestments or any amount that represents appreciation in the value of your shares. For purposes of calculating a CDSC, the start of the holding period is generally the first day of the month in which your purchase was made.

When you place an order to sell shares of a class that has a CDSC, the Fund will first redeem any shares that are not subject to a CDSC, followed by those you have held the longest. This means that if a CDSC is imposed, you cannot designate the individual shares being redeemed for U.S. federal income tax purposes. You should consult your tax advisor about the tax consequences of investing in the Fund. In certain circumstances, the CDSC may not apply. See Choosing a Share Class — Reductions/Waivers of Sales Charges for details.

Share Class Features

The following summarizes the primary features of Class A, Class Adv, Class C, Class Inst, Class Inst2, Class Inst3, and Class R shares.

Not all Funds offer every class of shares. The Fund offers the class(es) of shares set forth on the cover of this prospectus and may offer other share classes through a separate prospectus. Although certain share classes are generally closed to new and/or existing investors, information relating to these share classes is included in the table below because certain qualifying purchase orders are permitted, as described below.

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The sales charge reductions and waivers available to investors who purchase and hold their Fund shares through different financial intermediaries may vary. Appendix A describes financial intermediary-specific reductions and/or waiver policies. A shareholder transacting in Fund shares through a financial intermediary identified in Appendix A should carefully read the terms and conditions of Appendix A. A reduction and/or waiver that is specific to a particular financial intermediary is not available to Direct-at-Fund Accounts, as defined below, or through another financial intermediary. The information in Appendix A may be provided by, or compiled from or based on information provided by the financial intermediaries identified in Appendix A. To obtain additional information regarding any sales charge reduction and/or waiver described in Appendix A, and to ensure that you receive any such reductions or waivers that may be available to you, please consult your financial intermediary.

Share Class	Eligible Investors; Minimum Initial Investments; Conversion Features(a)	Front-End Sales Charges(b)	Contingent Deferred Sales Charges (CDSCs)(b)	Sales Charge Reductions/Waivers	Maximum Distribution and/or Service (12b-1) Fees(c)
Class A	Eligibility: Available to the general public for investment Minimum Initial Investment: $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts (as described below))	5.75% maximum, declining to 0.00% on investments of $1 million or more	CDSC on certain investments of between $1 million and $50 million redeemed within 18 months after purchase charged as follows: • 1.00% CDSC if redeemed within 12 months after purchase and • 0.50% CDSC if redeemed more than 12, but less than 18, months after purchase	Reductions: yes, see Choosing a Share Class — Reductions/Waivers of Sales Charges – Class A Shares Front-End Sales Charge Reductions Waivers: yes, on Fund distribution reinvestments. For additional waivers, see Choosing a Share Class — Reductions/Waivers of Sales Charges – Class A Shares Front-End Sales Charge Waivers, as well as Choosing a Share Class — CDSC Waivers – Class A and Class C Financial intermediary-specific waivers are also available, see Appendix A	Service Fee: 0.25%
Class Adv	Eligibility: Available only to (i) omnibus retirement plans, including self-directed brokerage accounts within omnibus retirement plans that clear through institutional no transaction fee (NTF) platforms; retirement plans; (ii) trust companies or similar institutions; (iii) broker-dealers, banks, trust companies and similar institutions that clear Fund share transactions for their client or customer investment advisory or similar accounts through designated financial intermediaries and their mutual fund trading platforms that have been granted specific written authorization from the Transfer Agent with respect to Class Adv eligibility apart from selling, servicing or similar agreements; (iv) 501(c)(3) charitable organizations; (v) 529 plans; (vi) health savings accounts; (vii) investors participating in a fee-based advisory program sponsored by a financial intermediary or other entity that is not compensated by the Fund for those services, other than payments for shareholder servicing or sub-accounting performed in place	None	None	N/A	None

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Share Class	Eligible Investors; Minimum Initial Investments; Conversion Features(a)	Front-End Sales Charges(b)	Contingent Deferred Sales Charges (CDSCs)(b)	Sales Charge Reductions/Waivers	Maximum Distribution and/or Service (12b-1) Fees(c)
	of the Transfer Agent; and (viii) commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Adv shares within such platform. Minimum Initial Investment: None, except in the case of (viii) above, which is $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts)
Class C	Eligibility: Available to the general public for investment Minimum Initial Investment: $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts) Conversion Feature: Yes. Effective April 1, 2021, Class C shares generally automatically convert to Class A shares of the same Fund in the month of or the month following the 8-year anniversary of the Class C shares purchase date. Prior to April 1, 2021, Class C shares generally automatically converted to Class A shares of the same Fund in the month of or the month following the 10-year anniversary of the Class C shares purchase date.(a)	None	1.00% on certain investments redeemed within one year of purchase	Waivers: yes, on Fund distribution reinvestments. For additional waivers, see Choosing a Share Class — CDSC Waivers – Class A and Class C Financial intermediary-specific CDSC waivers are also available, see Appendix A	Distribution Fee: 0.75% Service Fee: 0.25%
Class Inst	Eligibility: Available only to certain eligible investors, which are subject to different minimum investment requirements, ranging from $0 to $2,000, including investors who purchase Fund shares through commissionable brokerage platforms where the financial intermediary holds the shares in an omnibus account and, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst shares within such platform; closed to (i) accounts of financial intermediaries that clear Fund share transactions for their client or customer accounts through designated financial intermediaries and their mutual fund	None	None	N/A	None

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Share Class	Eligible Investors; Minimum Initial Investments; Conversion Features(a)	Front-End Sales Charges(b)	Contingent Deferred Sales Charges (CDSCs)(b)	Sales Charge Reductions/Waivers	Maximum Distribution and/or Service (12b-1) Fees(c)
	trading platforms that have been given specific written notice from the Transfer Agent of the termination of their eligibility for new purchases of Class Inst shares and (ii) omnibus group retirement plans, subject to certain exceptions(d) Minimum Initial Investment: See Eligibility above
Class Inst2	Eligibility: Available only to (i) certain registered investment advisers and family offices that clear Fund share transactions for their client or customer accounts through designated financial intermediaries and their mutual fund trading platforms that have been granted specific written authorization from the Transfer Agent with respect to Class Inst2 eligibility apart from selling, servicing or similar agreements; (ii) omnibus retirement plans(d); (iii) health savings accounts, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst2 shares within such platform and that Fund shares are held in an omnibus account; and (iv) institutional investors that are clients of the Columbia Threadneedle Global Institutional Distribution Team that invest in Class Inst2 shares for their own account through platforms approved by the Distributor or an affiliate thereof to offer and/or service Class Inst2 shares within such platform. Minimum Initial Investment: None	None	None	N/A	None
Class Inst3	Eligibility: Available to: (i) group retirement plans that maintain plan-level or omnibus accounts with the Fund(d); (ii) institutional investors that are clients of the Columbia Threadneedle Global Institutional Distribution Team that invest in Class Inst3 shares for their own account through platforms approved by the Distributor or an affiliate thereof to offer and/or service Class Inst3 shares within such platform; (iii) collective trust funds; (iv) affiliated or unaffiliated mutual funds (e.g., funds operating as funds-of-funds); (v) fee-based platforms of financial intermediaries (or the clearing intermediary they trade through) that have an agreement with the	None	None	N/A	None

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Share Class	Eligible Investors; Minimum Initial Investments; Conversion Features(a)	Front-End Sales Charges(b)	Contingent Deferred Sales Charges (CDSCs)(b)	Sales Charge Reductions/Waivers	Maximum Distribution and/or Service (12b-1) Fees(c)
	Distributor or an affiliate thereof that specifically authorizes the financial intermediary to offer and/or service Class Inst3 shares within such platform, provided also that Fund shares are held in an omnibus account; (vi) commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst3 shares within such platform and that Fund shares are held in an omnibus account; (vii) health savings accounts, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst3 shares within such platform and that Fund shares are held in an omnibus account; and (viii) bank trust departments, subject to an agreement with the Distributor that specifically authorizes offering Class Inst3 shares and provided that Fund shares are held in an omnibus account. In each case above where noted that Fund shares are required to be held in an omnibus account, the Distributor, may, in its discretion, determine to waive this requirement. Minimum Initial Investment: No minimum for the eligible investors described in (i), (iii), (iv) and (v) above; $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts) for the eligible investors described in (vi) above; and $1 million for all other eligible investors, unless waived in the discretion of the Distributor
Class R	Eligibility: Available only to eligible retirement plans, health savings accounts and, in the sole discretion of the Distributor, other types of retirement accounts held through platforms maintained by financial intermediaries approved by the Distributor Minimum Initial Investment: None	None	None	N/A	Distribution Fee: 0.50%

(a) For more information on the conversion of Class C shares to Class A shares, see Choosing a Share Class — Sales Charges and Commissions — Class C Shares —Conversion to Class A Shares.

(b) For more information on applicable sales charges, see Choosing a Share Class — Sales Charges and Commissions, and for information about certain exceptions to these sales charges, see Choosing a Share Class — Reductions/Waivers of Sales Charges.

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(c) These are the maximum applicable distribution and/or service fees under the Fund’s Rule 12b-1 plan. Because these fees are paid out of Fund assets on an ongoing basis, over time these fees will increase the cost of your investment and may cost you more than paying other types of distribution and/or service fees. For more information on distribution and service fees, see Choosing a Share Class — Distribution and Service Fees.

(d) These share classes are closed to new accounts generally or to new accounts of certain categories of investors, subject to certain conditions, as summarized below and described in more detail under Buying, Selling and Exchanging Shares — Buying Shares — Eligible Investors:

•  Class Inst Shares: Financial intermediaries that clear Fund share transactions through designated financial intermediaries and their mutual fund trading platforms that were given specific written notice from the Transfer Agent of the termination, effective March 29, 2013, of their eligibility for new purchases of Class Inst shares and omnibus retirement plans are not permitted to establish new Class Inst accounts, subject to certain exceptions. Omnibus retirement plans that opened and, subject to exceptions, funded a Class Inst account as of close of business on March 28, 2013, and have continuously held Class Inst shares in such account after such date, may generally continue to make additional purchases of Class Inst shares, open new Class Inst accounts and add new participants. In certain circumstances and in the sole discretion of the Distributor, omnibus retirement plans affiliated with a grandfathered plan may also open new Class Inst accounts. Accounts of financial intermediaries (other than omnibus retirement plans) that clear Fund share transactions for their client or customer accounts through designated financial intermediaries and their mutual fund trading platforms are not permitted to establish new Class Inst accounts or make additional purchases of Class Inst shares (other than through reinvestment of distributions).

•  Class Inst2 Shares. Shareholders with Class Inst2 accounts funded before November 8, 2012 who do not satisfy the current eligibility criteria for Class Inst2 shares may not establish new Class Inst2 accounts but may continue to make additional purchases of Class Inst2 shares in existing accounts. In addition, investment advisory programs and similar programs that opened a Class Inst2 account as of May 1, 2010, and continuously hold Class Inst2 shares in such account after such date, may generally not only continue to make additional purchases of Class Inst2 shares but also open new Class Inst2 accounts and add new shareholders in the program.

•  Class Inst3 Shares: Shareholders with Class Inst3 accounts funded before November 8, 2012 who do not satisfy the current eligibility criteria for Class Inst3 shares may not establish new accounts for such share class but may continue to make additional purchases of Class Inst3 shares in existing accounts.

Sales Charges and Commissions

Sales charges, commissions, and distribution fees compensate financial intermediaries (typically your financial advisor) for selling shares to you, and service fees compensate financial intermediaries for maintaining and servicing the shares held in your account with them. Distribution and service fees are discussed in a separate sub-section below. Depending on which share class you choose and the financial intermediary through which you purchase your shares, you may pay these charges at potentially different levels at the outset as a front-end sales charge, at the time you sell your shares as a CDSC and/or over time in the form of distribution and/or service fees. You may be required to pay brokerage commissions and other fees to financial intermediaries when transacting in any class of Fund shares, including those that do not assess any front-end sales charge, contingent deferred sales charge, or other asset-based fee for sales or distribution. Such brokerage commissions and other fees are set by the financial intermediary.

As described in more detail below, Class A shares have a front-end sales charge, which is deducted from your purchase price when you buy your shares, and results in a smaller dollar amount being invested in the Fund than the purchase price you pay (unless you qualify for a waiver or reduction of the sales charge). The Fund’s other share classes do not have a front-end sales charge, so the full amount of your purchase price is invested in those classes. Class A shares have lower ongoing distribution and/or service fees than Class C and Class R shares of the Fund. Over time, Class C and Class R shares can incur distribution and/or service fees that are equal to or more than the front-end sales charge and the distribution and/or service fees you would pay for Class A shares. Although the full amount of your purchase price of Class C and Class R shares is invested in a Fund, your return on this money will be reduced by the expected higher annual expenses of Class C and Class R shares. In this regard, note that effective April 1, 2021, Class C shares will generally automatically convert to Class A shares of the same Fund in the month of or the month following the 8-year anniversary of the Class C shares purchase date (prior to April 1, 2021, the 10-year anniversary of such date). The Fund may convert Class C shares held through a financial intermediary to Class A shares sooner in connection with the withdrawal of Class C shares of the Fund from the financial intermediary’s platform or accounts. No sales charge or other charges will apply in connection with such conversions, and the conversions are free from U.S. federal income tax. Once your Class C shares convert to Class A shares, your total returns from an investment in the Fund may increase as a result of the lower operating costs of Class A shares. Class Adv, Class Inst, Class Inst2 and Class Inst3 shares of the Fund do not have distribution and/or service fees.

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Whether the ultimate cost is higher for one share class over another depends on the amount you invest, how long you hold your shares, the fees (i.e., sales charges) and expenses of the class and whether you are eligible for reduced or waived sales charges, if available. You are responsible for choosing the share class most appropriate for you after taking into account your share class eligibility, class-specific features, and any applicable reductions in, or waivers of, sales charges. For more information, see Choosing a Share Class – Reductions/Waivers of Sales Charges. We encourage you to consult with a financial advisor who can help you with your investment decisions. Please contact your financial intermediary for more information about services, fees and expenses, and other important information about investing in the Fund, as well as with any questions you may have about your investing options. In all instances, it is your responsibility to notify your financial intermediary or (for Direct-at-Fund Accounts, as defined below) the Fund at the time of purchase of any relationship or other facts that may qualify you for sales charge waivers or discounts.

Class A Shares — Front-End Sales Charge

Unless your purchase qualifies for a waiver (e.g., you buy the shares through reinvested Fund dividends or distributions or subject to an applicable financial intermediary-specific waiver), you will pay a front-end sales charge when you buy Class A shares, resulting in a smaller dollar amount being invested in a Fund than the purchase price you pay. The Class A shares sales charge is waived on Class C shares converted to Class A shares. For more information about sales charge waivers and reduction opportunities, see Choosing a Share Class — Reductions/Waivers of Sales Charges and Appendix A.

The Distributor receives the sales charge and re-allows (or pays) a portion of the sales charge to the financial intermediary through which you purchased the shares. The Distributor retains the balance of the sales charge.

The front-end sales charge you will pay on Class A shares:

■ depends on the amount you are investing (generally, the larger the investment, the smaller the percentage sales charge), and

■ is based on the total amount of your purchase and the value of your account (and any other accounts eligible for aggregation of which you or your financial intermediary notifies the Fund).

The table below presents the front-end sales charge as a percentage of both the offering price and the net amount invested.

Class A Shares — Front-End Sales Charge — Breakpoint Schedule
Breakpoint Schedule For:	Dollar amount of shares bought(a)	Sales charge as a % of the offering price(b)	Sales charge as a % of the net amount invested(b)	Amount retained by or paid to financial intermediaries as a % of the offering price
Class A Shares	$0–$49,999	5.75%	6.10%	5.00%
	$50,000–$99,999	4.50%	4.71%	3.75%
	$100,000–$249,999	3.50%	3.63%	3.00%
	$250,000–$499,999	2.50%	2.56%	2.15%
	$500,000–$999,999	2.00%	2.04%	1.75%
	$1,000,000 or more	0.00%	0.00%	0.00%(c)

(a) Purchase amounts and account values may be aggregated among all eligible Fund accounts for the purposes of this table. See Choosing a Share Class — Reductions/Waivers of Sales Charges for a discussion of account value aggregation.

(b) Because the offering price is calculated to two decimal places, the dollar amount of the sales charge as a percentage of the offering price and your net amount invested for any particular purchase of Fund shares may be higher or lower depending on whether downward or upward rounding was required during the calculation process. Purchase price includes the sales charge.

(c) For information regarding cumulative commissions paid to your financial intermediary when you buy $1 million or more of Class A shares of a Fund, see Class A Shares — Commissions below.

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Class A Shares — CDSC

In some cases, you'll pay a CDSC if you sell Class A shares that you purchased without a front-end sales charge.

■ If you purchased Class A shares without an initial sales charge because your accounts aggregated between $1 million and $50 million at the time of purchase, you will incur a CDSC if you redeem those shares within 18 months after purchase, which is charged as follows: 1.00% CDSC if shares are redeemed within 12 months after purchase; and 0.50% CDSC if shares are redeemed more than 12, but less than 18, months after purchase.

■ Subsequent Class A share purchases that bring your aggregate account value to $1 million or more (but less than $50 million) will also be subject to a CDSC if you redeem them within the time periods noted above.

Class A Shares — Commissions

The Distributor may pay your financial intermediary an up-front commission when you buy Class A shares. The Distributor generally funds the commission through the applicable sales charge you paid. For more information, see Class A Shares — Front-End Sales Charge above.

The Distributor may also pay your financial intermediary a cumulative commission when you buy Class A shares in amounts not subject to a front-end sales charge, according to the following schedules (assets initially purchased into Class A shares of Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund and Columbia U.S. Treasury Index Fund that were purchased without the application of a front-end sales charge are excluded for purposes of calculating a financial intermediary’s commission under these schedules):

Class A Shares — Commission Schedule (Paid by the Distributor to Financial Intermediaries)
Purchase Amount	Commission Level* (as a % of net asset value per share)
$1 million – $2,999,999	1.00%
$3 million – $49,999,999	0.50%
$50 million or more	0.25%

* The commission level applies to the applicable asset level; therefore, for example, for a purchase of $5 million, the Distributor would pay a commission of 1.00% on the first $2,999,999 and 0.50% on the balance.

Class C Shares — Front-End Sales Charge

You do not pay a front-end sales charge when you buy Class C shares, but you may pay a CDSC when you sell Class C shares. Although Class C shares do not have a front-end sales charge, over time Class C shares can incur distribution and/or service fees that are equal to or more than the front-end sales charge and distribution and/or service fees you would pay for Class A shares. Thus, although the full amount of your purchase of Class C shares is invested in a Fund, any positive investment return on this money may be partially or fully offset by the expected higher annual expenses of Class C shares.

Class C Shares — Conversion to Class A Shares

Effective April 1, 2021, Class C shares of a Fund generally automatically convert to Class A shares of the same Fund in the month of or the month following the 8-year anniversary of the Class C shares purchase date. Prior to April 1, 2021, Class C shares of a Fund generally automatically converted to Class A shares of the same Fund in the month of or in the month following the 10-year anniversary of the Class C shares purchase date. Class C shares held through a financial intermediary in an omnibus account will be converted (pursuant to the financial intermediary’s Class C conversion policy, including those disclosed in Appendix A, which may differ from the Fund’s policy described here) provided that the intermediary is able to track individual shareholders’ holding periods. It is the financial intermediary's (and not the Fund's) responsibility to keep records and to ensure that the shareholder holding period is calculated properly. Not all financial intermediaries are able to track individual shareholders' holding periods. For example, group retirement plans held through third-party intermediaries that hold Class C shares in an omnibus account may not track participant level share lot aging. Please consult with your financial intermediary about your

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eligibility for Class C share conversion. The Fund may convert Class C shares held through a financial intermediary to Class A shares sooner in connection with the withdrawal of Class C shares of the Fund from the financial intermediary's platform or accounts. Once your Class C shares convert to Class A shares, your total returns from an investment in the Fund may increase as a result of the lower operating costs of Class A shares.

The following rules apply to the automatic conversion of Class C shares to Class A shares:

■ Class C share accounts that are Direct-at-Fund Accounts and Networked Accounts for which the Transfer Agent (and not your financial intermediary) sends you Fund account transaction confirmations and statements, convert on or about the 15th day of the month (if the 15th is not a business day, then the next business day thereafter) that they become eligible for automatic conversion provided that the Fund has records that Class C shares have been held for the requisite time period.

■ For purposes of determining the month when your Class C shares are eligible for conversion, the start of the holding period is the first day of the month in which your purchase was made. Your financial intermediary may choose a different day of the month to convert Class C shares. Please contact your financial intermediary for more information on calculating the holding period.

■ Any shares you received from reinvested distributions on these shares generally will convert to Class A shares at the same time.

■ You’ll receive the same dollar value of Class A shares as the Class C shares that were automatically converted. Class C shares that you received from an exchange of Class C shares of another Fund will convert based on the day you bought the original shares.

■ In addition to the above automatic conversion of Class C to Class A shares policy, the Transfer Agent seeks to convert Class C shares as soon as administratively feasible, regardless of how long such shares have been owned, to Class A shares of the same Fund for Direct-at-Fund Accounts (as defined below) that do not or no longer have a financial intermediary assigned to them. Direct-at-Fund Accounts that do not have a financial intermediary assigned to them are not permitted to purchase Class C shares; Class C share purchase orders received by Direct-at-Fund Accounts that do not have a financial intermediary assigned to the account will automatically be invested in Class A shares of the same Fund.

■ No sales charge or other charges apply in connection with these automatic conversions, and the conversions are free from U.S. federal income tax.

Class C Shares — CDSC

You will pay a CDSC of 1.00% if you redeem Class C shares within 12 months of buying them unless you qualify for a waiver of the CDSC (e.g., the shares you are selling were purchased with reinvested Fund distributions). Redemptions of Class C shares are not subject to a CDSC if redeemed after 12 months. For more information, see Choosing a Share Class — Reductions/Waivers of Sales Charges.

Class C Shares — Commissions

Although there is no front-end sales charge when you buy Class C shares, the Distributor makes an up-front payment (which includes a sales commission and an advance of service fees) directly to your financial intermediary of up to 1.00% of the NAV per share when you buy Class C shares. A portion of this payment may be passed along to your financial advisor. The Distributor seeks to recover this payment through distribution fees of up to 0.75% and shareholder service fees of up to 0.25% it receives under the Fund's Rule 12b-1 plan during the first 12 months following the sale of Class C shares, and any applicable CDSC when you sell your shares. For more information, see Choosing a Share Class — Distribution and Service Fees.

Reductions/Waivers of Sales Charges

The availability of certain sales charge waivers and discounts will depend on whether you purchase your shares directly from the Fund (i.e., a Direct-at-Fund Account, as defined below) or through a financial intermediary. Financial intermediaries may have different policies and procedures regarding the availability of front-end sales charge and/or CDSC waivers. In all instances, it is your responsibility to notify your financial intermediary or (for Direct-at-Fund

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Accounts, as defined below) the Fund at the time of purchase of any relationship or other facts that may qualify you for sales charge waivers or discounts. In order to obtain waivers and discounts not available through a particular financial intermediary, shareholders will have to purchase Fund shares directly from the Fund (if permitted) or through a different financial intermediary. For a description of financial intermediary-specific sales charge reductions and/or waivers, see Appendix A.

Class A Shares Front-End Sales Charge Reductions

The Fund makes available two means of reducing the front-end sales charge that you may pay when you buy Class A shares of a Fund. These types of sales charge reductions are also referred to as breakpoint discounts.

First, through the right of accumulation (ROA), you may combine the value of eligible accounts (as described in the Eligible Accounts section below) maintained by you and members of your immediate family to reach a breakpoint discount level and apply a lower front-end sales charge to your purchase. To calculate the combined value of your eligible Fund accounts in the particular class of shares, the Fund will use the current public offering price per share. For purposes of obtaining a breakpoint discount through ROA, you may aggregate your and your “immediate family” members' ownership (as described in the FUNDamentals box below) of certain classes of shares held in certain account types, as described in the Eligible Accounts section below.

Second, by making a statement of intent to purchase additional shares (commonly referred to as a letter of intent (LOI)), you may pay a lower sales charge on all purchases of Class A shares made within 13 months after the date of your LOI. Your LOI must state the aggregate amount of purchases you intend to make in that 13-month period, which must be at least enough to reach the first (or next) breakpoint of the Fund. The required form of LOI may vary by financial intermediary, so please contact them directly for more information. Five percent of the purchase commitment amount will be placed in escrow. At the end of the 13-month period, the shares will be released from escrow, provided that you have invested the commitment amount. If you do not invest the commitment amount by the end of the 13 months, the remaining amount of the unpaid sales charge will be redeemed from the escrowed shares and the remaining balance released from escrow. To calculate the total value of the purchases you've made under an LOI, the Fund will use the historic cost (i.e., dollars invested and not current market value) of the shares held in each eligible account; reinvested dividends or capital gains, or purchases made through the reinstatement privilege do not count as purchases made under an LOI. For purposes of making an LOI to purchase additional shares, you may aggregate eligible shares owned by you or your immediate family members in eligible accounts, valued as of the day immediately before the initiation of your LOI.

You must request the reduced sales charge (whether through ROA or an LOI) when you buy shares. If you do not complete and file an LOI, or do not request the reduced sales charge at the time of purchase, you will not be eligible for the reduced sales charge. To obtain a breakpoint discount, you must notify your financial intermediary in writing at the time you buy your shares of each eligible account maintained by you and members of your immediate family, including accounts maintained through different financial intermediaries. You and your financial intermediary are responsible for ensuring that you receive discounts for which you are eligible. Please contact your financial intermediary with questions regarding application of the eligible discount to your account. You may be asked by your financial intermediary (or by the Fund if you hold your account directly with the Fund) for account statements or other records to verify your discount eligibility for new and subsequent purchases, including, when applicable, records for accounts opened with a different financial intermediary and records of accounts established by members of your immediate family.

The sales charge reductions available to investors who purchase and hold their Fund shares through different financial intermediaries may vary. For a description of such financial intermediary-specific sales charge reductions, see Appendix A.

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 FUNDamentals

Your “Immediate Family” and Account Value Aggregation

For purposes of obtaining a breakpoint discount for Class A shares, the value of your account will be deemed to include the value of all applicable shares in eligible Fund accounts that are held by you and your “immediate family,” which includes your spouse, domestic partner, parent, step-parent, legal guardian, child under 21, step-child under 21, father-in-law and mother-in-law, provided that you and your immediate family members share the same mailing address. Any Fund accounts linked together for account value aggregation purposes as of the close of business on September 3, 2010 will be permitted to remain linked together. Group retirement plan accounts are valued at the retirement plan level.

Eligible Accounts

The following accounts are eligible for account value aggregation as described above, provided that they are invested in Class A (excluding, in the case of Direct-at-Fund Accounts, Funds that do not assess a front-end sales charge, including Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund and Columbia U.S. Treasury Index Fund, unless such shares were purchased via an exchange from Class A shares of a Fund on which you paid the Class A share applicable front-end sales charge), Class C, Class E, Class Inst or Class V shares of a Fund, or non-retirement plan accounts invested in Class Adv, Class Inst2 or Class Inst3 shares of a Fund: individual or joint accounts; Roth and traditional Individual Retirement Accounts (IRAs); Simplified Employee Pension accounts (SEPs), Savings Investment Match Plans for Employees of Small Employers accounts (SIMPLEs) and Tax Sheltered Custodial Accounts (TSCAs); Uniform Gifts to Minors Act (UGMA)/Uniform Transfers to Minors Act (UTMA) accounts for which you, your spouse, or your domestic partner is parent or guardian of the minor child; revocable trust accounts for which you or an immediate family member, individually, is the beneficial owner/grantor; accounts held in the name of your, your spouse’s, or your domestic partner’s sole proprietorship or single owner limited liability company or S corporation; qualified retirement plan assets, provided that you are the sole owner of the business sponsoring the plan, are the sole participant (other than a spouse) in the plan, and have no intention of adding participants to the plan; and investments in wrap accounts.

The following accounts are not eligible for account value aggregation as described above: accounts of pension and retirement plans with multiple participants, such as 401(k) plans (which are combined to reduce the sales charge for the entire pension or retirement plan and therefore are not used to reduce the sales charge for your individual accounts); investments in 529 plans, donor advised funds, variable annuities, variable insurance products or managed separate accounts; charitable and irrevocable trust accounts; accounts holding shares of money market funds that used the Columbia brand before May 1, 2010; accounts invested in Class R shares of a Fund; and retirement plan accounts invested in Class Adv, Class Inst2 or Class Inst3 shares of a Fund.

Additionally, direct purchases of shares of Columbia Government Money Market Fund may not be aggregated for account value aggregation purposes; however, shares of Columbia Government Money Market Fund acquired by exchange from other Columbia Funds that assess a sales charge may be included in account value aggregation.

Class A Shares Front-End Sales Charge Waivers

There are no front-end sales charges on reinvested Fund distributions. The Class A shares sales charge is waived on conversions of Class C shares to Class A shares. The Distributor may waive front-end sales charges on purchases of Class A shares of the Funds by certain categories of investors, including Board members, certain employees of financial intermediaries, Fund portfolio managers, certain partners and employees of outside legal counsel to the Funds or the Board, separate accounts of an insurance company exempt from registration as an investment company under Section 3(c)(11) of the 1940 Act, registered broker-dealer firms that have an agreement with the Distributor purchasing Fund shares for their investment account only, and qualified employee benefit plan rollovers to Class A

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shares in the same Fund (see Appendix S to the SAI for details). For a more complete description of categories of investors who may purchase Class A shares of the Funds at NAV, without payment of any front-end sales charge that would otherwise apply, see Appendix S to the SAI.

In addition, certain types of purchases of Class A shares may be made at NAV. The Distributor may waive front-end sales charges on (i) purchases (including exchanges) of Class A shares in accounts of financial intermediaries that have entered into agreements with the Distributor to offer Fund shares to self-directed investment brokerage accounts that may or may not charge a transaction fee to customers; (ii) exchanges of Class Inst shares of a Fund for Class A shares of the Fund; (iii) purchases of Class A shares on brokerage mutual fund-only platforms of financial intermediaries that have an agreement with the Distributor that specifically authorizes the offering of Class A shares within such platform; (iv) purchases through certain wrap fee or other products or programs that involve fee-based compensation arrangements that have, or clear trades through a financial intermediary that has, a selling agreement with the Distributor; (v) purchases through state sponsored 529 Plans; (vi) purchases through banks, trust companies, and thrift institutions acting as fiduciaries; (vii) purchases through certain employee benefit plans and certain qualified deferred compensation plans; and (viii) purchases of Class A shares in Direct-at-Fund Accounts (as defined below) that do not have a financial intermediary assigned to them. For a more complete description of these eligible transactions, see Appendix S to the SAI.

The sales charge waivers available to investors who purchase and hold their Fund shares through different financial intermediaries may vary. For a description of such financial intermediary-specific sales charge waivers, see Appendix A.

CDSC Waivers – Class A and Class C

You may be able to avoid an otherwise applicable CDSC when you sell Class A or Class C shares of the Fund. This could happen because of the way in which you originally invested in the Fund, because of your relationship with the Funds or for other reasons. For example, the CDSC will be waived on redemptions of shares: in the event of the shareholder's death; for which no sales commission or transaction fee was paid to an authorized financial intermediary at the time of purchase; purchased through reinvestment of dividends and capital gain distributions; that result from required minimum distributions taken from retirement accounts due to the shareholder reaching the qualified age based on applicable IRS regulations; that result from returns of excess contributions made to retirement plans or individual retirement accounts (subject to certain conditions); initially purchased by an employee benefit plan (for Class A shares) and that are not connected with a plan level termination (for Class C shares); in connection with the Fund's Small Account Policy (which is described in Buying, Selling and Exchanging Shares — Transaction Rules and Policies); held within Direct-at-Fund Accounts that do not have a financial intermediary assigned to them; and by certain other investors and in certain other types of transactions or situations. Restrictions may apply to certain accounts and certain transactions. The Distributor may, in its sole discretion, authorize the waiver of the CDSC for additional classes of investors. The Fund may change or cancel these terms at any time. Any change or cancellation applies only to future purchases. For a more complete description of the available waivers of the CDSC on redemptions of Class A or Class C shares, see Appendix S to the SAI.

The sales charge waivers available to investors who purchase and hold their Fund shares through different financial intermediaries may vary. For a description of such financial intermediary-specific sales charge waivers, see Appendix A.

Repurchases (Reinstatements)

As noted in the table below, you can redeem shares of certain classes (see Redeemed Share Class below) and use such redemption proceeds to buy shares of the Corresponding Repurchase Class without paying an otherwise applicable sales charge and/or CDSC (other than, in the case of Direct-at-Fund Accounts, redemptions from Funds that do not assess a front-end sales charge, including Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund and Columbia U.S. Treasury Index Fund, unless such shares were purchased via an exchange from Class A shares of a Fund on which you paid the Class A share applicable front-end sales charge) within 90 days, up to the amount of the redemption proceeds.

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Columbia Acorn International®

Choosing a Share Class (continued)

Repurchases (Reinstatements)
Redeemed Share Class	Corresponding Repurchase Class
Class A	Class A
Class C	Class C

Any CDSC paid upon redemption of your Class A or Class C shares of a Fund will not be reimbursed.

To be eligible for the repurchase (or reinstatement) privilege, the purchase must be made into an account for the same owner, but does not need to be into the same Fund from which the shares were sold. The Transfer Agent, Distributor or their agents must receive a written reinstatement request from you or your financial intermediary within 90 days after the shares are redeemed. The purchase of the Corresponding Repurchase Class (as noted in the table above) through this repurchase (or reinstatement) privilege will be made at the NAV of such shares next calculated after the request is received in “good form.” Systematic withdrawals and purchases are excluded from this policy.

Restrictions and Changes in Terms and Conditions

Restrictions may apply to certain accounts and certain transactions. The Funds and/or the Distributor may change or cancel these terms and conditions at any time. Unless you provide your financial intermediary with information in writing about all of the factors that may count toward available reductions or waivers of an applicable sales charge, there can be no assurance that you will receive all of the reductions and waivers for which you may be eligible. To the extent your Fund account is held directly with the Fund, you should provide this information to the Fund when placing your purchase or redemption order. Please see Appendix A to this prospectus and Appendix S of the SAI for more information about sales charge waivers.

Distribution and Service Fees

The Board has approved, and the Columbia Acorn Funds have adopted, a distribution plan pursuant to Rule 12b-1 under the 1940 Act that sets the distribution and/or service fees that are periodically deducted from the Funds’ assets. These fees are calculated daily, may vary by share class and are intended to compensate the Distributor and/or eligible financial intermediaries for, with regard to distribution fees, selling Fund shares and, with regard to service fees, directly or indirectly providing services to shareholders. Because the fees are paid out of the Fund's assets on an ongoing basis, they will increase the cost of your investment over time.

The table below shows the maximum annual distribution and/or service fees (as an annual percentage of average daily net assets) and the combined amount of such fees applicable to each share class of the Columbia Acorn Funds:

	Distribution Fee	Service Fee	Combined Total
Class A	None	0.25%	0.25%
Class Adv	None	None	None
Class C	0.75%	0.25%	1.00%
Class Inst	None	None	None
Class Inst2	None	None	None
Class Inst3	None	None	None
Class R	0.50%	None	0.50%

The distribution and/or service fees for Class A, Class C, and Class R shares, as applicable, are subject to the requirements of Rule 12b-1 under the 1940 Act. The Distributor may retain these fees otherwise payable to financial intermediaries if the amounts due are below an amount determined by the Distributor in its sole discretion.

For Class A shares, the Distributor begins to pay these fees immediately after purchase, except in the following case, in which the Distributor begins to pay these fees 12 months after purchase: a purchase of Class A shares of $1 million or more that pay a Class A up-front commission to your financial intermediary and the financial intermediary has opted to receive such commission. The Distributor’s policy to otherwise begin to pay these fees immediately on

Prospectus 2022 41

Columbia Acorn International®

Choosing a Share Class (continued)

Class A shares also applies to purchases of funds that do not pay an up-front sales commission on Class A shares, which includes Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund and Columbia U.S. Treasury Index Fund. For Class C shares, the Distributor begins to pay these fees 12 months after purchase. However, for Class C shares, financial intermediaries may opt to decline the up-front payment described in Choosing a Share Class – Sales Charges and Commissions – Class C Shares – Commissions and instead may receive these fees immediately after purchase. If the intermediary opts to receive the up-front payment, the Distributor retains the distribution and service fee for the first 12 months following the sale of Class C shares in order to recover the up-front payment made to financial intermediaries and to pay for other related expenses. For Class R shares, the Distributor begins to pay these fees immediately after purchase.

If you maintain shares of the Fund directly with the Fund, without working with a financial advisor or other financial intermediary, distribution and service fees may be retained by the Distributor as payment or reimbursement for incurring certain distribution and shareholder service related expenses.

Over time, these distribution and/or service fees will reduce the return on your investment and may cost you more than paying other types of sales charges. The Fund will pay these fees to the Distributor and/or to eligible financial intermediaries for as long as the distribution plan continues in effect, which is expected to be indefinitely. However, the Fund may reduce or discontinue payments at any time. Your financial intermediary may also charge you other additional fees for providing services to your account, which may be different from those described here.

Financial Intermediary Compensation

The Distributor, the Investment Manager and their affiliates make payments, from their own resources, to financial intermediaries, including other Ameriprise Financial affiliates, for marketing/sales support services relating to the Funds (Marketing Support Payments). Such payments are generally based upon one or more of the following factors: average net assets of the Funds attributable to that financial intermediary; gross sales of the Funds attributable to that financial intermediary; reimbursement of ticket charges (fees that a financial intermediary charges its representatives for effecting transactions in Fund shares); or a negotiated lump sum payment. While the financial arrangements may vary for each financial intermediary, Marketing Support Payments to any one financial intermediary are generally between 0.01% and 0.40% on an annual basis for payments based on average net assets of the Fund attributable to the financial intermediary, and between 0.05% and 0.25% on an annual basis for firms receiving a payment based on gross sales of the Funds attributable to the financial intermediary. The Distributor, the Investment Manager and their affiliates make payments with respect to a Fund or the Columbia Funds generally on a basis other than those described above or in larger amounts when dealing with certain financial intermediaries. Not all financial intermediaries receive Marketing Support Payments. The Distributor, the Investment Manager and their affiliates do not make Marketing Support Payments with respect to Class Inst3 shares of the Columbia Acorn Funds.

In addition, the Transfer Agent has certain arrangements in place to compensate financial intermediaries, including other Ameriprise Financial affiliates, that hold Fund shares through networked and omnibus accounts, including omnibus retirement plans, for services that they provide to beneficial Fund shareholders (Shareholder Services). Shareholder Services and related fees vary by financial intermediary and according to distribution channel and may include sub-accounting, sub-transfer agency, participant recordkeeping, shareholder or participant reporting, shareholder or participant transaction processing, maintenance of shareholder records, preparation of account statements and provision of customer service, and are not intended to include services that are primarily intended to result in the sale of Fund shares. Payments for Shareholder Services vary by financial intermediary and according to distribution channel, but generally are not expected, with certain limited exceptions, to exceed 0.40% of the average aggregate value of the Fund’s shares. Payments to financial intermediaries in excess of the amounts paid by the Fund are borne by the Distributor, the Investment Manager and/or their affiliates.

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Choosing a Share Class (continued)

Generally, each Fund in the Columbia Acorn Family of Funds compensates the Transfer Agent for payments made for Shareholder Services, for each share class except Class Inst3. Effective July 1, 2017, the Columbia Acorn Funds compensate the Transfer Agent for payments made for Shareholder Services as follows:

Financial Intermediary Distribution Channel	Fee Rate
Retirement	up to 0.18% of Fund assets held by intermediaries or platforms charging an asset-based fee, or $18 per account held by intermediaries or platforms charging a per account fee
Fund supermarket transaction fee (TF)	up to 0.12% of Fund assets held by intermediaries or platforms charging an asset-based fee, or $16 per account held for intermediaries or platforms charging a per account fee
Fund supermarket no-transaction fee (NTF)	up to 0.18% of Fund assets held by intermediaries or platforms charging an asset-based fee, or $18 per account held by intermediaries or platforms charging a per account fee
Bank	up to 0.10% of Fund assets held by intermediaries or platforms charging an asset-based fee, or $20 per account held by intermediaries or platforms charging a per account fee
Broker-dealer	up to 0.13% of Fund assets held by intermediaries or platforms charging an asset-based fee, or $16 per account held by intermediaries or platforms charging a per account fee

With respect to Class Inst2 and Class Inst3 shares of the Fund, total annual compensation payable to the Transfer Agent may not exceed, respectively, 0.07% and 0.02% of the average daily net assets of the Class. For additional details about the application of the Columbia Acorn Funds’ fee limits, please refer to the SAI.

The Transfer Agent does not pay financial intermediaries for Shareholder Services, and the Fund does not compensate the Transfer Agent for any Shareholder Services provided by financial intermediaries with respect to Class Inst3 shares of the Columbia Acorn Funds. The Fund believes that the fee levels paid to the Transfer Agent are reasonably related to the Shareholder Services provided, but payments may vary and there can be no assurance that the Fund will be able to identify with specificity the costs or particular Shareholder Services for which compensation is paid.

In addition to the payments described above, the Distributor, the Investment Manager and their affiliates typically make other payments or allow promotional incentives to certain broker-dealers to the extent permitted by the Securities and Exchange Commission (the SEC) and Financial Industry Regulatory Authority (FINRA) rules and by other applicable laws and regulations.

Amounts paid by the Distributor, the Investment Manager and their affiliates are paid out of their own resources and do not increase the amount paid by you or the Fund. You can find further details in the SAI about the payments made by the Distributor, the Investment Manager and their affiliates, as well as a list of the financial intermediaries, including Ameriprise Financial affiliates, to which the Distributor and the Investment Manager have agreed to make Marketing Support Payments and pay Shareholder Services fees.

Your financial intermediary may charge you fees and commissions in addition to those described in this prospectus. You should consult with your financial intermediary and review carefully any disclosure your financial intermediary provides regarding its services and compensation. Depending on the financial arrangement in place at any particular time, a financial intermediary and its financial advisors may have a conflict of interest or financial incentive for recommending the Fund or a particular share class over others.

Prospectus 2022 43

Columbia Acorn International®

Buying, Selling and Exchanging Shares

Share Price Determination

The price you pay or receive when you buy, sell or exchange shares is the Fund's next determined net asset value (or NAV) per share for a given share class. The Fund calculates the NAV per share for each class of shares of the Fund at the end of each business day, with the value of the Fund's shares based on the total value of all of the securities and other assets that it holds as of such specified time.

 FUNDamentals

NAV Calculation

Each of the Fund's share classes calculates its NAV per share as follows:

NAV per share =  (Value of assets of the share class) – (Liabilities of the share class)
Number of outstanding shares of the class

 FUNDamentals

Business Days

A business day is any day that the New York Stock Exchange (NYSE) is open. A business day ends at (i) the scheduled close of the NYSE for such day (usually 4:00 p.m. Eastern Time or such other time as the NYSE may schedule), (ii) the scheduled close of the NYSE (usually 4:00 p.m. Eastern Time) on any business day on which the NYSE has an unscheduled close or intraday trading halt or other disruption, regardless of the time of such unscheduled close, halt or disruption or whether trading resumes, or (iii) such other time as the Board may from time to time determine. On holidays and other days when the NYSE is closed, the Fund’s NAV is not calculated and the Fund does not accept buy or sell orders. However, the value of the Fund’s assets may still be affected on such days to the extent that the Fund holds foreign securities that trade on days that foreign securities markets are open.

Equity securities are valued primarily on the basis of market quotations reported on stock exchanges and other securities markets around the world. Certain equity securities, debt securities and other assets are valued differently. For instance, short-term investments maturing in 60 days or less are valued primarily using the amortized cost method and those maturing in excess of 60 days are valued at the readily available market price. For a Fund organized as a fund-of-funds, its investments in other funds are valued at their NAVs. Market quotations are obtained from outside pricing services approved and monitored pursuant to a policy approved by the Fund’s Board.

If a market price is not readily available or is deemed not to reflect market value, the security will be valued in good faith based on a determination of the security's fair value pursuant to the Portfolio Pricing Policy approved by the Board. The Portfolio Pricing Policy provides that fair value determinations will be made using the methodology set forth in the Policy and deemed most appropriate under the circumstances and considering all available, relevant factors and indications of value. The Portfolio Pricing Policy provides that fair valuation may be used to price securities that trade on a foreign exchange when a significant event has occurred after the foreign exchange closes but before the time at which the Fund's share price is calculated. In addition, a statistical fair valuation process is applied daily to adjust prices of foreign securities traded on foreign exchanges in time zones different from the United States utilizing the services of a designated pricing vendor. Although the use of statistical fair valuation is intended to and may decrease opportunities for time zone arbitrage transactions, there can be no assurance that it will successfully decrease arbitrage opportunities. Please consult the SAI for more information on the factors to be considered in making fair value determinations; the significant events that may necessitate fair valuation of foreign securities; and the Fund's statistical fair valuation methodology.

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Buying, Selling and Exchanging Shares (continued)

When fair valuation is used to price securities, the values for those securities may be higher or lower than values used by another fund to price the security. Also, the use of fair valuation may cause the Fund's performance to diverge to a greater degree from the performance of various benchmarks used to compare the Fund's performance because benchmarks generally do not use fair valuation techniques. Because of the judgment involved in fair valuation decisions, there can be no assurance that the value ascribed to a particular security is accurate.

Transaction Rules and Policies

The Fund, the Distributor or the Transfer Agent may refuse any order to buy or exchange shares. If this happens, the Fund will return any money it received, but no interest will be paid on that money. Your financial intermediary may have rules and policies in place that are in addition to or different than those described below.

Order Processing

Orders to buy, sell or exchange Fund shares are processed on business days. Depending upon the class of shares, orders can be made by mail, by telephone or online. Orders received in “good form” by the Transfer Agent or your financial intermediary before the end of a business day are priced at the NAV per share (plus any applicable sales charge) of the Fund's applicable share class on that day. Orders received after the end of a business day will receive the next business day's NAV per share (plus any applicable sales charge). For Direct-at-Fund Accounts (as defined below), when a written order to buy, sell or exchange shares is sent to the Transfer Agent, the share price used to fill the order is the next price calculated by the Fund after the Transfer Agent receives the transaction request in “good form” at its transaction processing center (i.e., the Fund’s express mail address), not the P.O. Box provided for regular mail delivery. The market value of the Fund's investments may change between the time you submit your order and the time the Fund next calculates its NAV per share. The business day that applies to your order is also called the trade date.

“Good Form”

An order is in “good form” if the Transfer Agent or your financial intermediary has received payment (in the case of purchases) and all of the information and documentation it deems necessary to effect your order. For example, when you sell shares, “good form” means that your request (i) has complete instructions and written requests include the signatures of all account owners, (ii) is for an amount that is less than or equal to the shares in your account for which payment has been received and collected, (iii) has a Medallion Signature Guarantee for amounts greater than $100,000 and certain other transactions, as described below, and (iv) includes any other required documents completed and attached. For the documents required for sales by corporations, agents, fiduciaries, surviving joint owners and other legal entities, call 800.345.6611.

Medallion Signature Guarantees

The Transfer Agent may require a Medallion Signature Guarantee for your signature in order to process certain transactions, including if: (i) the transaction amount is over $100,000; (ii) you want your check made payable to someone other than the registered account owner(s); (iii) the address of record has changed within the last 30 days; (iv) you want the check mailed to an address other than the address of record; (v) you want proceeds to be sent according to existing bank account instructions not coded for outgoing Automated Clearing House (ACH) or wire, or to a bank account not on file; or (vi) you are changing legal ownership of your account.

A Medallion Signature Guarantee helps assure that a signature is genuine and not a forgery. A Medallion Signature Guarantee must be provided by an eligible guarantor institution including, but not limited to, the following: a bank, credit union, savings association, broker or dealer that participates in the Securities Transfer Association Medallion Program (STAMP), the Stock Exchange Medallion Program (SEMP) or the New York Stock Exchange Medallion Signature Program (MSP). For other transactions, the Transfer Agent may require a signature guarantee. Notarization by a notary public is not an acceptable signature guarantee. The Transfer Agent reserves the right to reject a signature guarantee and to request additional documentation for any transaction.

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Columbia Acorn International®

Buying, Selling and Exchanging Shares (continued)

Customer Identification Program

Federal law requires the Fund to obtain and record specific personal information to verify your identity when you open an account. This information may include your name, address, date of birth (for individuals) and taxpayer or other government issued identification (e.g., social security number (SSN) or other taxpayer identification number (TIN)). If you fail to provide the requested information, the Fund may need to delay the date of your purchase or may be unable to open your account, which may result in a return of your investment monies. In addition, if the Fund is unable to verify your identity after your account is open, the Fund reserves the right to close your account or take other steps as deemed reasonable. The Fund will not be liable for any loss resulting from any purchase delay, application rejection or account closure due to a failure to provide proper identifying information.

Small Account Policy — Class A, Class C, and Class Inst Share Accounts Below the Minimum Account Balance

The Funds generally will automatically sell your shares if the value of your Fund account (treating each account of the Fund you own separately from any other account of the Fund you may own) falls below the applicable minimum account balance. Any otherwise applicable CDSC will not be imposed on such an automatic sale of your shares. Generally, you may avoid such an automatic sale by raising your account balance to at least $250 or consolidating your multiple accounts you may have with the Funds through an exchange (so as to maintain at least $250 in each of your accounts). The minimum account balance varies among share classes and types of accounts, as follows:

Minimum Account Balance
	Minimum Account Balance
For all classes and account types except those listed below	$250 (None for accounts with Systematic Investment Plans)
Individual Retirement Accounts for all classes except those listed below	None
Class Adv, Class Inst2, Class Inst3 and Class R	None

For shares held directly with the Funds’ Transfer Agent, if your shares are sold, the Transfer Agent will remit the sale proceeds to you. The Transfer Agent will send you written notification in advance of any automatic sale, which will provide details on how you may avoid such an automatic sale. Generally, you may avoid such an automatic sale by raising your account balance to at least $250, consolidating your multiple accounts you may have with the Funds through an exchange (so as to maintain at least $250 in each of your accounts), or setting up a Systematic Investment Plan. For more information, contact the Transfer Agent or your financial intermediary. The Transfer Agent's contact information (toll-free number and mailing addresses) as well as the Funds’ website address can be found at the beginning of the section Choosing a Share Class.

For shares purchased and held for your benefit through a financial intermediary, the Funds may instruct the intermediary to automatically sell your Fund shares if the transaction can be operationally administered by the intermediary.

Small Account Policy — Class A, Class C, and Class Inst Share Accounts Minimum Balance Fee

If the value of your Fund account (treating each account of the Fund you own separately from any other account of the Fund you may own) falls below the minimum initial investment requirement applicable to you for any reason, including as a result of market decline, your account generally could be subject to a $20 annual fee. The Transfer Agent will reduce the expenses paid by the Fund by any amounts it collects from the assessment of this fee. For Funds that do not have transfer agency expenses against which to offset the amount collected through assessment of this fee, the fee will be paid directly to the Fund. The Funds reserve the right to lower the account size trigger point for the minimum balance fee in any year or for any class of shares when we believe it is appropriate to do so in light of declines in the market value of Fund shares or for other reasons.

For shares held directly with the Funds’ Transfer Agent, this fee will be assessed through the automatic sale of Fund shares in your account. Any otherwise applicable CDSC will not be imposed on such an automatic sale of your shares. The Transfer Agent will send you written notification in advance of assessing any fee, which will provide

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Columbia Acorn International®

Buying, Selling and Exchanging Shares (continued)

details on how you can avoid the imposition of such fee. Generally, you may avoid the imposition of such fee by raising your Fund account balance, consolidating your multiple accounts you may have with the Funds, or setting up a Systematic Investment Plan that invests at least monthly. For more information, contact the Transfer Agent or your financial intermediary. The Transfer Agent's contact information (toll-free number and mailing addresses) as well as the Funds’ website address can be found at the beginning of the section Choosing a Share Class.

For shares purchased and held for your benefit through a financial intermediary, this fee could be assessed through the automatic sale of Fund shares in your account if instructed by the Fund and the transaction can be operationally administered by the intermediary.

Exceptions to the Small Account Policy (Accounts Below Minimum Account Balance) and Minimum Balance Fee

The automatic sale of Fund shares in accounts under $250 and the annual minimum balance fee described above do not apply to shareholders of Class Adv, Class Inst2, Class Inst3 and Class R shares; shareholders holding their shares through financial intermediary networked accounts; wrap fee and omnibus accounts; accounts with active monthly Systematic Investment Plans; certain qualified retirement plans; and health savings accounts. The automatic sale of Fund shares of accounts under the applicable minimum account balance does not apply to individual retirement plans.

Small Account Policy — Financial Intermediary Networked and Wrap Fee Accounts

The Funds may automatically redeem, at any time, financial intermediary networked accounts and wrap fee accounts that have account balances of $20 or less or have less than one share.

For shares purchased and held for your benefit through a financial intermediary, the Funds may instruct the intermediary to automatically sell your Fund shares if the transaction can be operationally administered by the intermediary.

Information Sharing Agreements

As required by Rule 22c-2 under the 1940 Act, the Funds or certain of their service providers will enter into information sharing agreements with financial intermediaries, including participating life insurance companies and financial intermediaries that sponsor or offer retirement plans through which shares of the Funds are made available for purchase. Pursuant to Rule 22c-2, financial intermediaries are required, upon request, to: (i) provide shareholder account and transaction information; and (ii) execute instructions from the Fund to restrict or prohibit further purchases of Fund shares by shareholders who have been identified by the Fund as having engaged in transactions that violate the Fund's excessive trading policies and procedures.

Excessive Trading Practices Policy

Right to Reject or Restrict Share Transaction Orders— The Fund is intended for investors with long-term investment purposes and is not intended as a vehicle for frequent trading activity (market timing) that is excessive. Investors should transact in Fund shares primarily for investment purposes. The Board has adopted excessive trading policies and procedures that are designed to deter excessive trading by investors (the Excessive Trading Policies and Procedures). The Fund discourages and does not accommodate excessive trading.

The Fund reserves the right to reject, without any prior notice, any purchase or exchange order for any reason, and will not be liable for any loss resulting from rejected orders. For example, the Fund may in its sole discretion restrict or reject a purchase or exchange order even if the transaction is not subject to the specific limitation described below if the Fund or its agents determine that accepting the order could interfere with efficient management of the Fund's portfolio or is otherwise contrary to the Fund's best interests. The Excessive Trading Policies and Procedures apply equally to purchase or exchange transactions communicated directly to the Transfer Agent and to those received by financial intermediaries.

Specific Buying and Exchanging Limitations — If the Fund detects that an investor has made two “material round trips” in any 28-day period, it will generally reject the investor's future purchase orders, including exchange purchase orders, involving any Fund.

Prospectus 2022 47

Columbia Acorn International®

Buying, Selling and Exchanging Shares (continued)

For these purposes, a “round trip” is a purchase or exchange into the Fund followed by a sale or exchange out of the Fund, or a sale or exchange out of the Fund followed by a purchase or exchange into the Fund. A “material” round trip is one that is deemed by the Fund to be material in terms of its amount or its potential detrimental impact on the Fund. Independent of this limit, the Fund may, in its sole discretion, reject future purchase orders by any person, group or account that appears to have engaged in any type of excessive trading activity.

These limits generally do not apply to automated transactions or transactions by registered investment companies in a “fund-of-funds” structure. These limits do not apply to payroll deduction contributions by retirement plan participants, transactions initiated by a retirement plan sponsor or certain other retirement plan transactions consisting of rollover transactions, loan repayments and disbursements, and required minimum distribution redemptions. They may be modified or rescinded for accounts held by certain retirement plans to conform to plan limits, for considerations relating to the Employee Retirement Income Security Act of 1974 or regulations of the Department of Labor, and for certain asset allocation or wrap programs. Accounts known to be under common ownership or control generally will be counted together, but accounts maintained or managed by a common intermediary generally will not be considered to be under common ownership or control. The Fund reserves the right to modify these restrictions at any time without prior notice to shareholders. In addition, the Fund may, in its sole discretion, reinstate trading privileges that have been revoked under the Fund's Excessive Trading Policies and Procedures.

Limitations on the Ability to Detect and Prevent Excessive Trading Practices — The Fund takes various steps designed to detect and prevent excessive trading, including daily review of available shareholder transaction information. However, the Fund receives buy, sell or exchange orders through financial intermediaries, and cannot always know of or reasonably detect excessive trading that may be facilitated by financial intermediaries or by the use of the omnibus account arrangements they offer. Omnibus account arrangements are common forms of holding shares of mutual funds, particularly among certain financial intermediaries such as broker-dealers, retirement plans and variable insurance products. These arrangements often permit financial intermediaries to aggregate their clients' transactions and accounts, and in these circumstances, the identities of the financial intermediary clients that beneficially own Fund shares are often not known to the Fund.

Some financial intermediaries apply their own restrictions or policies to their clients’ transactions and accounts, which may be more or less restrictive than those described here. This may impact the Fund's ability to curtail excessive trading, even where it is identified. For these and other reasons, it is possible that excessive trading may occur despite the Fund's efforts to detect and prevent it.

Although these restrictions and policies involve judgments that are inherently subjective and may involve some selectivity in their application, the Fund seeks to act in a manner that it believes is consistent with the best interests of Fund shareholders in making any such judgments.

Risks of Excessive Trading — Excessive trading creates certain risks to the Fund's long-term shareholders and may create the following adverse effects:

■ negative impact on the Fund's performance;

■ potential dilution of the value of the Fund's shares;

■ interference with the efficient management of the Fund's portfolio, such as the need to maintain undesirably large cash positions, the need to use its line of credit or the need to buy or sell securities it otherwise would not have bought or sold;

■ losses on the sale of investments resulting from the need to sell securities at less favorable prices;

■ increased taxable gains to the Fund's remaining shareholders resulting from the need to sell securities to meet sell orders; and

■ increased brokerage and administrative costs.

To the extent that the Fund invests significantly in foreign securities traded on markets that close before the Fund's valuation time, it may be particularly susceptible to dilution as a result of excessive trading. Because events may occur after the close of foreign markets and before the Fund's valuation time that influence the value of foreign

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Buying, Selling and Exchanging Shares (continued)

securities, investors may seek to trade Fund shares in an effort to benefit from their understanding of the value of foreign securities as of the Fund's valuation time. This is often referred to as price arbitrage. The Fund has adopted procedures designed to adjust closing market prices of foreign securities under certain circumstances to reflect what the Fund believes to be the fair value of those securities as of its valuation time. To the extent the adjustments do not work fully, investors engaging in price arbitrage may cause dilution in the value of the Fund's shares held by other shareholders.

The Columbia Acorn Funds may invest in thinly traded equity securities of small-capitalization companies. Because

these securities are often traded infrequently, investors may seek to trade Fund shares in an effort to benefit from their understanding of the value of these securities as of the Fund's valuation time. This is also a type of price arbitrage. Any such frequent trading strategies may interfere with efficient management of the Fund's portfolio to a greater degree than would be the case for mutual funds that invest only, or significantly, in highly liquid securities, in part because the Fund may have difficulty selling these particular investments at advantageous times or prices to satisfy large and/or frequent sell orders. Any successful price arbitrage may also cause dilution in the value of Fund shares held by non-redeeming shareholders.

Opening an Account and Placing Orders

We encourage you to consult with a financial advisor who can help you with your investment decisions and who can help you open an account. Once you have an account, you can buy, sell or exchange shares by contacting your financial advisor who will send your order to the Transfer Agent or your financial intermediary. As described below, once you have an account you can also communicate your orders directly to the Transfer Agent by mail, by telephone or online.

The Funds are generally available directly and through broker-dealers, banks and other financial intermediaries or institutions, and through certain qualified and non-qualified plans, wrap fee products or other investment products sponsored by financial intermediaries. You may buy, sell, or exchange shares through your financial intermediary. If you maintain your account directly with your financial intermediary, you must contact that agent to process your transaction.

Not all financial intermediaries offer the Funds (or all classes of Fund shares) and certain financial intermediaries that offer the Funds may not offer all Funds on all investment platforms or programs. Please consult with your financial intermediary to determine the availability of the Funds. If you set up an account at a financial intermediary that does not have, and is unable to obtain, a selling agreement with the Distributor, you will not be able to transfer Fund holdings to that account. In that event, you must either maintain your Fund holdings with your current financial intermediary or find another financial intermediary with a selling agreement.

Financial intermediaries that offer the Funds may charge you additional fees for the services they provide and they may have different policies that are not described in this prospectus. An investor transacting in a class of Fund shares without any front-end sales charge, CDSC, or other asset-based fee for sales or distribution, such as a Rule 12b-1 fee, may be required to pay a commission to the financial intermediary for effecting such transactions. The Funds are offered in a number of different share classes that have different fees and expenses and other features. Some differences in the policies of different financial intermediaries may include different minimum investment amounts, exchange privileges, Fund/class choices and cutoff times for investments. Additionally, recordkeeping, transaction processing and payments of distributions relating to your account may be performed by the financial intermediaries through which your shares of the Fund are held. Since the Fund (and its service providers) may not have a record of your account transactions, you should always contact the financial intermediary through which you purchased or at which you maintain your shares of the Fund to make changes to your account, to give instructions concerning your account, or to obtain information about your account. The Fund and its service providers, including the Distributor and the Transfer Agent, are not responsible for the failure of any financial intermediary to carry out its obligations to its customers.

The Fund may engage financial intermediaries to receive purchase, exchange and sell orders on its behalf. Accounts established directly with the Fund will be serviced by the Transfer Agent. The Funds, the Transfer Agent and the Distributor do not provide investment advice.

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Direct-At-Fund Accounts (Accounts Held Directly with the Fund)

Fund shares can be held in a variety of ways. You can hold Fund shares through an account established and held through the financial intermediary through which you purchased Fund shares, or you or your financial intermediary can establish an account directly with the Fund, in which case you will receive Fund account transaction confirmations and statements from the Transfer Agent, and not your financial intermediary (Direct-at-Fund Accounts). Direct-at-Fund Accounts include accounts held at the Transfer Agent that do not or no longer have a financial intermediary assigned to them.

To open a Direct-at-Fund Account, complete a Fund account application with your financial advisor or investment professional, and mail the account application to the Transfer Agent. Account applications may be obtained at columbiathreadneedleus.com or may be requested by calling 800.345.6611. Make your check payable to the Fund. You will be assessed a $15 fee for any checks rejected by your financial institution due to insufficient funds or other reasons. The Funds do not accept cash, credit card convenience checks, money orders, traveler's checks, starter checks, third or fourth party checks, or other cash equivalents.

Mail your check and completed application to the Transfer Agent at its regular or express mail address that can be found at the beginning of the section Choosing a Share Class. You may also use these addresses to request an exchange or redemption of Fund shares. When a written order to buy, sell or exchange shares is sent to the Transfer Agent, the share price used to fill the order is the next price calculated by the Fund after the Transfer Agent receives your transaction request in “good form” at its transaction processing center (i.e., the Fund’s express mail address), not the P.O. Box provided for regular mail delivery.

You will be sent a statement confirming your purchase and any subsequent transactions in your account. You will also be sent quarterly and annual statements detailing your transactions in the Fund and the other Funds you own under the same account. Duplicate quarterly account statements for the current year and duplicate annual statements for the most recent prior calendar year will be sent to you free of charge. Copies of year-end statements for prior years are available for a fee. Please contact the Transfer Agent for more information.

Written Transactions – Direct-at-Fund Accounts

If you have a Direct-at-Fund Account, you can communicate written buy, sell or exchange orders to the Transfer Agent at its address that can be found at the beginning of the section Choosing a Share Class. When a written order to buy, sell or exchange shares is sent to the Transfer Agent, the share price used to fill the order is the next price calculated by the Fund after the Transfer Agent receives your transaction request in “good form” at its transaction processing center (i.e., the Fund’s express mail address), not the P.O. Box provided for regular mail delivery.

Include in your transaction request letter: your name; the name of the Fund(s); your account number; the class of shares to be purchased, exchanged or sold; your SSN or other TIN; the dollar amount or number of shares you want to purchase, exchange or sell; specific instructions regarding delivery of any redemption proceeds or exchange destination (i.e., the Fund/class to be exchanged into); signature(s) of all registered account owner(s); and any special documents the Transfer Agent may require in order to process your order.

Corporate, trust or partnership accounts may need to send additional documents. Payment will be mailed to the address of record and made payable to the names listed on the account, unless your request specifies differently and is signed by all owners.

Telephone Transactions – Direct-at-Fund Accounts

For Class A, Class C, Class Inst, Class Inst3 and Class R shares, if you have a Direct-at-Fund Account, you may place orders to buy, sell or exchange shares by telephone through the Transfer Agent. To place orders by telephone, call 800.422.3737. Have your account number and SSN or TIN available when calling.

You can sell Fund shares via telephone and receive redemption proceeds: by electronic funds transfer via ACH, by wire, or by check to the address of record, subject to a maximum of $100,000 of shares per day, per Fund account. You can buy Fund shares via telephone by electronic funds transfer via ACH from your bank account up to a maximum

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of $100,000 of shares per day, per Fund account, or by wire from your bank account without a maximum. See below for more information regarding wire and electronic fund transfer transactions. Certain restrictions apply, so please call the Transfer Agent at 800.422.3737 for this and other information in advance of any need to transact via telephone.

Telephone orders may not be as secure as written orders. The Fund will take reasonable steps to confirm that telephone instructions are genuine. For example, we require proof of your identification before we will act on instructions received by telephone and may record telephone conversations. However, the Fund and its agents will not be responsible for any losses, costs or expenses resulting from an unauthorized telephone instruction when reasonable steps have been taken to confirm that telephone instructions are genuine. Telephone orders may be difficult to complete during periods of significant economic or market change or business interruption.

Online Transactions – Direct-at-Fund Accounts

For Class A, Class C, Class Inst, Class Inst3 and Class R shares, if you have a Direct-at-Fund Account, you may be able to place orders to buy, sell, or exchange shares online. Contact the Transfer Agent at 800.345.6611 for more information on certain account trading restrictions and the special sign-up procedures required for online transactions. You can also go to columbiathreadneedleus.com/investor/ to sign up for online transactions. The Transfer Agent has procedures in place to authenticate electronic orders you send through the internet. You will be required to accept the terms of an online agreement and to establish an online account and utilize a password in order to access online account services. You can sell a maximum of $100,000 of shares per day, per Fund account through your online account if you qualify for internet orders. Wire transactions are not permitted online.

Wire Transactions – Direct-at-Fund Accounts

If you hold a Direct-at-Fund Account, you may purchase or redeem Class A, Class C, Class Inst, Class Inst3 and Class R shares of a Fund by wiring money from (or to) your bank account to (or from) your Fund account. You must set up this feature prior to your request unless you are submitting your request in writing, which may require a Medallion Signature Guarantee. Please contact the Transfer Agent by calling 800.422.3737 to obtain the necessary forms and requirements. The Transfer Agent charges a fee for shares sold by wire. The Transfer Agent may waive the fee for certain accounts. In the case of a redemption, the receiving bank may charge an additional fee. The minimum amount that can be redeemed by wire is $500. When selling Fund shares via a telephone request, the maximum amount that can be redeemed via wire transfer is $100,000 per day, per Fund account. Wire transactions are not permitted online.

Electronic Funds Transfer via ACH – Direct-at-Fund Accounts

If you hold a Direct-at-Fund Account, you may purchase or redeem Class A, Class C, Class Inst, Class Inst3 and Class R shares of a Fund by electronically transferring money via Automated Clearing House (ACH) from (or to) your bank account to (or from) your Fund account subject to a maximum of $100,000 of shares per day, per Fund account. You must set up this feature prior to your request, unless you are submitting your request in writing, which may require a Medallion Signature Guarantee. Please contact the Transfer Agent by calling 800.422.3737 to obtain the necessary forms and requirements. Your bank may take up to three business days to post an electronic funds transfer to (or from) your Fund account.

Buying Shares

Eligible Investors

Class A Shares

Class A shares are available to the general public for investment.

Class Adv Shares

Class Adv shares are available only to (i) omnibus retirement plans, including self-directed brokerage accounts within omnibus retirement plans that clear through institutional no transaction fee (NTF) platforms, (ii) trust companies or similar institutions, (iii) broker-dealers, banks, trust companies and similar institutions that clear Fund share

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transactions for their client or customer investment advisory or similar accounts through designated financial intermediaries and their mutual fund trading platforms that have been granted specific written authorization from the Transfer Agent with respect to Class Adv eligibility apart from selling, servicing or similar agreements, (iv) 501(c)(3) charitable organizations, (v) 529 plans, (vi) health savings accounts, (vii) investors participating in a fee-based advisory program sponsored by a financial intermediary or other entity that is not compensated by the Fund for those services, other than payments for shareholder servicing or sub-accounting performed in place of the Transfer Agent, and (viii) commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Adv shares within such platform.

Class C Shares

Class C shares are available to the general public for investment, except that Direct-at-Fund Accounts that do not have a financial intermediary assigned to them are not permitted to purchase Class C shares; Class C share purchase orders received on or after such date from Direct-at-Fund Accounts that do not have a financial intermediary assigned to the account will automatically be invested in Class A shares of the same Fund.

Class Inst Shares

Class Inst shares are available only to the categories of eligible investors described below under Class Inst Shares Minimum Initial Investments. Financial intermediaries that clear Fund share transactions through designated financial intermediaries and their mutual fund trading platforms that were given specific written notice from the Transfer Agent of the termination, effective March 29, 2013, of their eligibility for new purchases of Class Inst shares and omnibus retirement plans are not permitted to establish new Class Inst accounts, subject to certain exceptions described below.

Omnibus retirement plans that opened and, subject to certain exceptions, funded a Class Inst account with the Fund as of the close of business on March 28, 2013 and have continuously held Class Inst shares in such account after such date (each, a grandfathered plan), may generally continue to make additional purchases of Class Inst shares, open new Class Inst accounts and add new participants. In addition, an omnibus retirement plan affiliated with a grandfathered plan may, in the sole discretion of the Distributor, open new Class Inst accounts in a Fund if the affiliated plan opened a Class Inst account on or before March 28, 2013. If an omnibus retirement plan invested in Class Inst shares changes recordkeepers after March 28, 2013, any new accounts established for that plan may not be established in Class Inst shares, but such a plan may establish new accounts in a different share class for which the plan is eligible.

Accounts of financial intermediaries (other than omnibus retirement plans, which are discussed above) that clear Fund share transactions for their client or customer accounts through designated financial intermediaries and their mutual fund trading platforms that received specific written notice from the Transfer Agent of the termination, effective March 29, 2013, of their eligibility for new purchases of Class Inst shares will not be permitted to establish new Class Inst accounts or make additional purchases of Class Inst shares (other than through reinvestment of distributions). Any such account may, at its holder’s option, exchange Class Inst shares of a Fund, without the payment of a sales charge, for Class A shares of the same Fund.

Class Inst2 Shares

Class Inst2 shares are available only to (i) certain registered investment advisers and family offices that clear Fund share transactions for their client or customer accounts through designated financial intermediaries and their mutual fund trading platforms that have been granted specific written authorization from the Transfer Agent with respect to Class Inst2 eligibility apart from selling, servicing or similar agreements; (ii) omnibus retirement plans; (iii) health savings accounts, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst2 shares within such platform and that Fund shares are held in an omnibus account; and (iv) institutional investors that are clients of the Columbia Threadneedle Global Institutional Distribution Team that invest in Class Inst2 shares for their own account through platforms approved by the Distributor or an affiliate thereof to offer and/or service Class Inst2 shares within such platform. Prior to November 8, 2012, Class Inst2

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shares were closed to new investors and new accounts, subject to certain exceptions. Existing shareholders who do not satisfy the new eligibility requirements for investment in Class Inst2 may not establish new Class Inst2 accounts but may continue to make additional purchases of Class Inst2 shares in accounts opened and funded prior to November 8, 2012; provided, however, that investment advisory programs and similar programs that opened a Class Inst2 account as of May 1, 2010, and continuously hold Class Inst2 shares in such account after such date, may generally not only continue to make additional purchases of Class Inst2 shares but also open new Class Inst2 accounts for such pre-existing programs and add new shareholders in the program.

Class Inst3 Shares

Class Inst3 shares are available to: (i) group retirement plans that maintain plan-level or omnibus accounts with the Fund (through the Transfer Agent); (ii) institutional investors that are clients of the Columbia Threadneedle Global Institutional Distribution Team that invest in Class Inst3 shares for their own account through platforms approved by the Distributor or an affiliate thereof to offer and/or service Class Inst3 shares within such platform; (iii) collective trust funds; (iv) affiliated or unaffiliated mutual funds (e.g., funds operating as funds-of-funds); (v) fee-based platforms of financial intermediaries (or the clearing intermediary that they trade through) that have an agreement with the Distributor or an affiliate thereof that specifically authorizes the financial intermediary to offer and/or service Class Inst3 shares within such platform, provided also that Fund shares are held in an omnibus account; (vi) commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst3 shares within such platform and that Fund shares are held in an omnibus account; (vii) health savings accounts, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst3 shares within such platform and that Fund shares are held in an omnibus account; and (viii) bank trust departments, subject to an agreement with the Distributor that specifically authorizes offering Class Inst3 shares and provided that Fund shares are held in an omnibus account. In each case above where noted that Fund shares are required to be held in an omnibus account, the Distributor may, in its discretion, determine to waive this requirement.

Class R Shares

Class R shares are available only to eligible health savings accounts sponsored by third party platforms, including those sponsored by Ameriprise Financial affiliates, eligible retirement plans and, in the sole discretion of the Distributor, other types of retirement accounts held through platforms maintained by financial intermediaries approved by the Distributor. Eligible retirement plans include any retirement plan other than individual 403(b) plans. Class R shares are generally not available for investment through retail nonretirement accounts, traditional and Roth IRAs, Coverdell Education Savings Accounts, SEPs, SAR-SEPs, Simple IRAs or 529 tuition programs. Contact the Transfer Agent or your retirement plan or health savings account administrator for more information about investing in Class R shares.

Additional Eligible Investors

In addition, the Distributor, in its sole discretion, may accept investments in any share class from investors other than those listed in this prospectus, and may also waive certain eligibility requirements for operational and other reasons, including but not limited to any requirement to maintain Fund shares in networked or omnibus accounts.

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Minimum Initial Investments

The table below shows the Fund’s minimum initial investment requirements, which may vary by class and type of account.

The Fund reserves the right to redeem your shares if your account falls below the Fund’s minimum initial investment requirement.

Minimum Initial Investments
	Minimum Initial Investment(a)	Minimum Initial Investment for Accounts with Systematic Investment Plans
For all classes and account types except those listed below	$2,000	$100
Individual Retirement Accounts for all classes except those listed below	$1,000	$100
Group retirement plans	None	N/A
Class Adv and Class Inst	$0, $1,000 or $2,000(b)	$100(b)
Class Inst2 and Class R	None	N/A
Class Inst3	$0, $1,000, $2,000 or $1 million(c)	$100(c)

(a) If your Class A, Class Adv, Class C, Class Inst, or Class Inst3 shares account balance falls below the minimum initial investment amount for any reason, including a market decline, you may be asked to increase it to the minimum initial investment amount or establish a monthly Systematic Investment Plan. If you do not do so, your account will be subject to a $20 annual low balance fee and/or shares may be automatically redeemed and the proceeds mailed to you if the account falls below the minimum account balance. See Buying, Selling and Exchanging Shares — Transaction Rules and Policies above. There is no minimum initial investment in Class A shares for accounts held in an omnibus account on a mutual fund only platform offered through your financial intermediary.

(b) The minimum initial investment in Class Adv shares is $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts) for commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customers, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Adv shares within such platform; for all other eligible Class Adv share investors (see Buying Shares – Eligible Investors – Class Adv Shares above), there is no minimum initial investment. The minimum initial investment amount for Class Inst shares is $0, $1,000 or $2,000 depending upon the category of eligible investor. See — Class Inst Shares Minimum Initial Investments below. The minimum initial investment amount for Systematic Investment Plan accounts is the same as the amount set forth in the first two rows of the table, as applicable.

(c) There is no minimum initial investment in Class Inst3 shares for: group retirement plans that maintain plan-level or omnibus accounts with the Fund; collective trust funds; affiliated or unaffiliated mutual funds (e.g., funds operating as funds-of-funds); and fee -based platforms of financial intermediaries (or the clearing intermediary that they trade through) that have an agreement with the Distributor or an affiliate thereof that specifically authorizes the financial intermediary to offer and/or service Class Inst3 shares within such platform and Fund shares are held in an omnibus account. The minimum initial investment in Class Inst3 shares is $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts) for commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst3 shares within such platform and Fund shares are held in an omnibus account. The minimum initial investment in Class Inst3 shares is $1 million, unless waived in the discretion of the Distributor, for the following investors: institutional investors that are clients of the Columbia Threadneedle Global Institutional Distribution Team that invest in Class Inst3 shares for their own account through platforms approved by the Distributor or an affiliate thereof to offer and/or service Class Inst3 shares within such platform; and bank trust departments, subject to an agreement with the Distributor that specifically authorizes offering Class Inst3 shares and provided that Fund shares are held in an omnibus account. The Distributor may, in its discretion, waive the $1 million minimum initial investment required for these Class Inst3 investors. In each case above where noted that Fund shares are required to be held in an omnibus account, the Distributor, may, in its discretion, determine to waive this requirement.

Additional Information about Minimum Initial Investments

The minimum initial investment requirements may be waived for accounts that are managed by an investment professional, or for accounts held in approved discretionary or non-discretionary wrap programs. The Distributor, in its sole discretion, may also waive minimum initial investment requirements for other account types.

Minimum investment and related requirements may be modified at any time, with or without prior notice. If your account is closed and then re-opened with a Systematic Investment Plan, your account must meet the then-current applicable minimum initial investment.

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Class Inst Shares Minimum Initial Investments

There is no minimum initial investment in Class Inst shares for the following categories of eligible investors:

■ Any health savings account sponsored by a third party platform.

■ Any investor participating in an account sponsored by a financial intermediary or other entity (that provides services to the account) that is paid a fee-based advisory fee by the investor and that is not compensated by the Fund for those services, other than payments for shareholder servicing or sub-accounting performed in place of the Transfer Agent.

■ Any commissionable brokerage account, if a financial intermediary has received a written approval from the Distributor to waive the minimum initial investment in Class Inst shares.

■ Any Trustee (or family member) of Columbia Acorn Trust.

■ Any employee (or family member) of the Investment Manager.

The minimum initial investment in Class Inst shares for the following categories of eligible investors is $1,000:

■ Individual retirement accounts (IRAs) on commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst shares within such platform.

■ Any current employee of Columbia Management Investment Advisers LLC, the Distributor or the Transfer Agent and immediate family members of any of the foregoing who share the same address are eligible to invest in Class Inst shares through an individual retirement account (IRA). If you maintain your account with a financial intermediary, you must contact that financial intermediary each time you seek to purchase shares to notify them that you qualify for Class Inst shares. If Class Inst shares are not available at your financial intermediary, you may consider opening a Direct-at-Fund Account. It is your obligation to advise your financial intermediary or (in the case of Direct-at-Fund Accounts) the Transfer Agent that you qualify for Class Inst shares; be prepared to provide proof thereof.

The minimum initial investment in Class Inst shares for the following categories of eligible investors is $2,000:

■ Investors (except investors in individual retirement accounts (IRAs)) who purchase Fund shares through commissionable brokerage platforms where the financial intermediary holds the shares in an omnibus account and, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst shares within such platform.

■ Any current employee of Columbia Management Investment Advisers LLC, the Distributor or the Transfer Agent and immediate family members of any of the foregoing who share the same address are eligible to invest in Class Inst shares (other than individual retirement accounts (IRAs), for which the minimum initial investment is $1,000). If you maintain your account with a financial intermediary, you must contact that financial intermediary each time you seek to purchase shares to notify them that you qualify for Class Inst shares. If Class Inst shares are not available at your financial intermediary, you may consider opening a Direct-at-Fund Account. It is your obligation to advise your financial intermediary or (in the case of Direct-at-Fund Accounts) the Transfer Agent that you qualify for Class Inst shares; be prepared to provide proof thereof.

■ Certain financial institutions and intermediaries, such as insurance companies, trust companies, banks, endowments, investment companies or foundations, buying shares for their own account, including Ameriprise Financial and its affiliates and/or subsidiaries.

■ Bank trust departments that assess their clients an asset-based fee.

■ Any trustee or director (or family member of a trustee or director) of a fund distributed by the Distributor (other than the Columbia Acorn Funds).

■ Certain other investors as set forth in more detail in the SAI.

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Systematic Investment Plan

The Systematic Investment Plan allows you to schedule regular purchases via automatic transfers from your bank account to the Fund on a monthly, quarterly or semiannual basis. Contact the Transfer Agent or your financial intermediary to set up the plan. Systematic Investment Plans may not be available for all share classes. With the exception of Columbia Government Money Market Fund, Systematic Investment Plan purchases will be confirmed on your quarterly account statement. Columbia Government Money Market Fund Systematic Investment Plan purchases will be confirmed at the time of the purchase. If establishing a Systematic Investment Plan to reduce the initial fund minimum, the plan needs to be established monthly to avoid the small account fee.

Dividend Diversification

Generally, you may automatically invest Fund distributions into the same class of shares (and in some cases certain other classes of shares) of another Fund without paying any applicable front-end sales charge. Call the Transfer Agent at 800.345.6611 for details. The ability to invest distributions from one Fund to another Fund may not be available to accounts held at all financial intermediaries.

Other Purchase Rules You Should Know

■ Once the Transfer Agent or your financial intermediary receives your purchase order in “good form,” your purchase will be made at the Fund’s next calculated public offering price per share, which is the NAV per share plus any sales charge that applies (i.e., the trade date).

■ Once the Fund receives your purchase request in “good form,” you cannot cancel it after the market closes.

■ You generally buy Class A shares at the public offering price per share because purchases of these share classes are generally subject to a front-end sales charge.

■ You buy Class Adv, Class C, Class Inst, Class Inst2, Class Inst3 and Class R shares at NAV per share because no front-end sales charge applies to purchases of these share classes.

■ The Distributor and the Transfer Agent reserve the right to cancel your order request if the Fund does not receive payment within two business days of receiving your purchase order request. The Fund will return any payment received for orders that have been cancelled, but no interest will be paid on that money.

■ Financial intermediaries are responsible for sending your purchase orders to the Transfer Agent and ensuring that the Fund receives your money on time.

■ Shares purchased are recorded on the books of the Fund. The Fund does not issue certificates.

■ You generally may make a purchase only into a Fund that is accepting investments.

Please also read Appendix A and contact your financial intermediary for more information regarding any reductions and/or waivers described therein.

Selling Shares

When you sell shares, the amount you receive may be more or less than the amount you invested. Your sale price will be the next NAV calculated after your request is received in “good form,” (i.e., the trade date) minus any applicable CDSC.

Systematic Withdrawal Plan

The Systematic Withdrawal Plan allows you to schedule regular redemptions from your account any business day on a monthly, quarterly or semiannual basis. Currently, Systematic Withdrawal Plans are generally available for Class A, Class Adv, Class C, Class Inst, Class Inst2, and Class Inst3 share accounts. Contact the Transfer Agent or your financial intermediary to set up the plan. To set up the plan, your account balance must meet the class minimum initial investment amount. A Systematic Withdrawal Plan cannot be set up on an account that already has a Systematic Investment Plan established. Note that a Medallion Signature Guarantee may be required if this service is established after your Fund account is opened.

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You can choose to receive your withdrawals via check or direct deposit into your bank account. The Fund will deduct any applicable CDSC from the withdrawals before sending redemption proceeds to you. You can cancel the plan by giving the Fund 30 days’ notice in writing or by calling the Transfer Agent at 800.422.3737. It’s important to remember that if you withdraw more than your investment in the Fund is earning, you'll eventually withdraw your entire investment.

Satisfying Fund Redemption Requests

When you sell your Fund shares, the Fund is effectively buying them back from you. This is called a redemption. Except as noted below with respect to newly purchased shares, the Fund typically expects to send you payment for your shares within two business days after your trade date. The Fund can suspend redemptions and/or delay payment of redemption proceeds for up to seven days. The Fund can also suspend redemptions and/or delay payment of redemption proceeds in excess of seven days under certain circumstances, including when the NYSE is closed or trading thereon is restricted or during emergency or other circumstances, including as determined by the SEC.

The Fund typically seeks to satisfy redemption requests from cash or cash equivalents held by the Fund, from the proceeds of orders to purchase Fund shares or from the proceeds of sales of Fund holdings effected in the normal course of managing the Fund. However, the Fund may have to sell Fund holdings, including in down markets, to meet heavier than usual redemption requests. For example, under stressed or abnormal market conditions or circumstances, including circumstances adversely affecting the liquidity of the Fund’s investments, the Fund may be more likely to be forced to sell Fund holdings to meet redemptions than under normal market circumstances. In these situations, the Fund’s portfolio managers may have to sell Fund holdings that would not otherwise be sold because, among other reasons, the current price to be received is less than the value of the holdings perceived by the Fund’s portfolio managers. The Fund may also, under certain circumstances (likely under stressed or abnormal market conditions or circumstances), borrow money under a credit facility to which the Fund and certain other Columbia Funds are parties. The Fund and the other Columbia Funds are limited as to the amount that each may individually and collectively borrow under the credit facility. As a result, borrowings available to the Fund under the credit facility might be insufficient, alone or in combination with the other strategies described herein, to satisfy Fund redemption requests. Please see About Fund Investments – Borrowings in the SAI for more information about the credit facility. The Fund is also limited in the total amount it may borrow. Please see About Fund Investments – Fundamental and Non-Fundamental Investment Policies in the SAI for more information about borrowing.

In addition, the Fund reserves the right to honor redemption orders in whole or in part with in-kind distributions of Fund portfolio securities instead of cash. Such in-kind distributions typically represent a pro-rata portion of Fund portfolio assets subject to adjustments (e.g., for non-transferable securities, round lots, and derivatives, if any). In the event the Fund distributes portfolio securities in kind, you may incur brokerage and other transaction costs associated with converting the portfolio securities you receive into cash. Also, the portfolio securities you receive may increase or decrease in value after they are distributed but before you convert them into cash. For U.S. federal income tax purposes, redemptions paid in securities are generally treated the same as redemptions paid in cash. The Trust has elected to be governed by Rule 18f-1 under the 1940 Act, which means that for each redeeming shareholder, the first $250,000, or 1% of the Fund's net asset value, whichever is less, will be paid in cash or cash equivalents and the remainder may be paid in kind.

While the Fund is not required (and may refuse in its discretion) to pay a redemption with an in-kind distribution of Fund portfolio securities and reserves the right to pay the redemption proceeds in cash, if you wish to request an in-kind redemption, please call the Transfer Agent at 800.345.6611. As a result of the operational steps needed to coordinate with the redeeming shareholder’s custodian, in-kind redemptions typically take several weeks to complete after a redemption request is received. The Fund and the redeeming shareholder will typically agree upon a redemption date. Since the Fund’s NAV may fluctuate during this time, the Fund’s NAV may be lower on the agreed-upon redemption date than on an earlier date on which the investment could have been redeemed for cash.

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Redemption of Newly Purchased Shares

You may not redeem shares for which the Fund has not yet received payment. Shares purchased by check or electronically by ACH when the purchase payment is not guaranteed will be considered in “good form” for redemption only after they have been held in your account for 6 calendar days after the trade date of the purchase (Collected Shares). If you request a redemption for an amount that, based on the NAV next calculated after your redemption request is received, includes any shares that are not yet Collected Shares, the Fund will only process the redemption up to the amount of the value of Collected Shares available in your account. You must submit a new redemption request if you wish to redeem those shares that were not yet Collected Shares at the time the original redemption request was received by the Fund.

Other Redemption Rules You Should Know

■ Once the Transfer Agent or your financial intermediary receives your redemption order in “good form,” your shares will be sold at the Fund’s next calculated NAV per share (i.e., the trade date). Any applicable CDSC will be deducted from the amount you're selling and the balance will be remitted to you.

■ Once the Fund receives your redemption request in “good form,” you cannot cancel it after the market closes.

■ The Distributor, in its sole discretion, reserves the right to liquidate Fund shares (of any class of the Fund) held in an omnibus account of a financial intermediary that clears Fund share transactions through a clearing intermediary or platform that charges certain maintenance fees to the Fund if the value of the omnibus account, at the Fund share class (i.e., CUSIP) level, falls below $100,000 (a CUSIP Liquidation Event). The Distributor will provide at least 90 days’ notice of a CUSIP Liquidation Event to financial intermediaries with impacted omnibus accounts. Shareholders invested in the Fund through such omnibus accounts can request through their financial intermediary a tax-free exchange to Class A shares or shareholders can consider holding their Fund shares in a Direct-at-Fund Account, provided requirements to transfer the account are fulfilled. You should discuss your options with your financial intermediary.

■ If you sell your shares that are held in a Direct-at-Fund Account, we will normally send the redemption proceeds by mail or electronically transfer them to your bank account the next business day after the trade date. Note that your bank may take up to three business days to post an electronic funds transfer from your account.

■ If you sell your shares through a financial intermediary, the Funds will normally send the redemption proceeds to your financial intermediary within two business days after the trade date.

■ No interest will be paid on uncashed redemption checks.

■ Other restrictions may apply to retirement accounts. For information about these restrictions, contact your retirement plan administrator.

■ For broker-dealer and wrap fee accounts: The Fund reserves the right to redeem your shares if your account falls below the Fund's minimum initial investment requirement. The Fund will notify your broker-dealer prior to redeeming shares, and will provide details on how to avoid such redemption.

■ Also keep in mind the Funds' Small Account Policy, which is described above in Buying, Selling and Exchanging Shares — Transaction Rules and Policies.

Exchanging Shares

You can generally sell shares of your Fund to buy shares of another Fund (subject to eligibility requirements), in what is called an exchange. You should read the prospectus of, and make sure you understand the investment objective, principal investment strategies, risks, fees and expenses of, the Fund into which you are exchanging. Although the Funds allow certain exchanges from one share class to another share class with higher expenses, you should consider the expenses of each class before making such an exchange. Please see Same-Fund Exchange Privilege below for more information.

You will be subject to a sales charge if, in a Direct-at-Fund Account, you exchange shares that have not previously paid a sales charge, including from Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia U.S.

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Columbia Acorn International®

Buying, Selling and Exchanging Shares (continued)

Treasury Index Fund or any other Columbia Fund that does not charge a front-end sales charge, into a Columbia Fund that does assess a sales charge. If you hold your Fund shares through certain financial intermediaries, you may have limited exchangeability among the Funds. Please contact your financial intermediary for more information.

Systematic Exchanges

You may buy Class A, Class C, Class Inst and Class Inst3 shares of a Fund by exchanging each month from another Fund for shares of the same class of the Fund at no additional cost, subject to the following exchange amount minimums: $50 each month for individual retirement accounts (i.e., tax qualified accounts); and $100 each month for non-retirement accounts. Contact the Transfer Agent or your financial intermediary to set up the plan.

Exchanges will continue as long as your balance in the Fund you are exchanging shares from is sufficient to complete the systematic monthly exchange, subject to the Funds' Small Account Policy described above in Buying, Selling and Exchanging Shares — Transaction Rules and Policies. You may terminate the program or change the amount you would like to exchange (subject to the $50 and $100 minimum requirements noted immediately above) by calling the Transfer Agent at 800.345.6611.

Other Exchange Rules You Should Know

■ Exchanges are made at the NAV next calculated (plus any applicable sales charge) after your exchange order is received in “good form” (i.e., the trade date).

■ Once the Fund receives your exchange request in “good form,” you cannot cancel it after the market closes.

■ The rules for buying shares of a Fund generally apply to exchanges into that Fund, including, if your exchange creates a new Fund account, it must satisfy the minimum investment amount, unless a waiver applies.

■ Shares of the purchased Fund may not be used on the same day for another exchange or sale.

■ If you exchange shares from Class A shares of Columbia Government Money Market Fund to a non-money market Fund, any further exchanges must be between shares of the same class. For example, if you exchange from Class A shares of Columbia Government Money Market Fund into Class C shares of a non-money market Fund, you may not exchange from Class C shares of that non-money market Fund back to Class A shares of Columbia Government Money Market Fund or Class A shares of any other Fund.

■ A sales charge may apply when you exchange shares of a Fund that were not assessed a sales charge at the time you purchased such shares. If you invest through a Direct-at-Fund Account in Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund, Columbia U.S. Treasury Index Fund or any other Columbia Fund that does not impose a front-end sales charge and then you exchange into a Fund that does assess a sales charge, your transaction is subject to a front-end sales charge if you exchange into Class A shares and to a CDSC if you exchange into Class C shares of the Columbia Funds.

■ If you purchased Class A shares of a Columbia Fund that imposes a front-end sales charge (and you paid any applicable sales charge) and you then exchange those shares into Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund, Columbia U.S. Treasury Index Fund or any other Columbia Fund that does not impose a front-end sales charge, you may exchange that amount to Class A of another Fund in the future, including dividends earned on that amount, without paying a sales charge.

■ If your shares are subject to a CDSC, you will not be charged a CDSC upon the exchange of those shares. Any CDSC will be deducted when you sell the shares you received from the exchange. The CDSC imposed at that time will be based on the period that begins when you bought shares of the original Fund and ends when you sell the shares of the Fund you received from the exchange. Any applicable CDSC charged will be the CDSC of the original Fund.

■ You may make exchanges only into a Fund that is legally offered and sold in your state of residence. Contact the Transfer Agent or your financial intermediary for more information.

Prospectus 2022 59

Columbia Acorn International®

Buying, Selling and Exchanging Shares (continued)

■ You generally may make an exchange only into a Fund that is accepting investments.

■ The Fund may change or cancel your right to make an exchange by giving the amount of notice required by regulatory authorities (generally 60 days for a material change or cancellation).

■ Unless your account is part of a tax-advantaged arrangement, an exchange for shares of another Fund is a taxable event, and you may recognize a gain or loss for tax purposes.

■ Changing your investment to a different Fund will be treated as a sale and purchase, and you will be subject to applicable taxes on the sale and sales charges on the purchase of the new Fund.

■ Class Inst shares of a Fund may be exchanged for Class A or Class Inst shares of another Fund. In certain circumstances, the front-end sales charge applicable to Class A shares may be waived on exchanges of Class Inst shares for Class A shares. See Buying, Selling and Exchanging Shares — Buying Shares — Eligible Investors — Class Inst Shares for details.

Same-Fund Exchange Privilege

Shareholders may be eligible to invest in other classes of shares of the same Fund, and may exchange their current shares for another share class if deemed eligible and offered by the Fund. Such same-Fund exchanges could include an exchange of one class for another with higher expenses. Before making such an exchange, you should consider the expenses of each class. Shareholders should contact their financial intermediaries to learn more about the details of the same-Fund exchange privilege. Exchanges out of Class A and Class C shares will be subject to any applicable CDSC. Financial intermediaries that have a customized arrangement with regard to CDSCs are detailed in Appendix A.

Exchanges out of Class C shares to another share class of the same Fund are not permissible on Direct-at-Fund Accounts, except that the Transfer Agent seeks to convert Class C shares as soon as administratively feasible to Class A shares of the same Fund for Direct-at-Fund Accounts that do not or no longer have a financial intermediary assigned to them. Direct-at-Fund Accounts that do not have a financial intermediary assigned to them are not permitted to purchase Class C shares. Class C share purchase orders received by Direct-at-Fund Accounts that do not have a financial intermediary assigned to the account will automatically be invested in Class A shares of the same Fund. Exchanges out of Class C shares to another share class of the same Fund within commissionable brokerage accounts are permitted only (1) when the shareholder moves from a commissionable brokerage account to a fee-based advisory program or (2) when the exchange is part of a share class conversion (or a similar multiple shareholder transaction event) instituted by a financial intermediary and such conversion or similar type event is preapproved by the Distributor.

Ordinarily, shareholders will not recognize a gain or loss for U.S. federal income tax purposes upon a same-Fund exchange. You should consult your tax advisor about your particular exchanges.

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Distributions and Taxes

Distributions to Shareholders

A mutual fund can make money two ways:

■ It can earn income on its investments. Examples of fund income are interest paid on money market instruments and bonds, and dividends paid on common stocks.

■ A mutual fund can also have capital gains if the value of its investments increases. While a fund continues to hold an investment, any gain is generally unrealized. If the fund sells an investment, it generally will realize a capital gain if it sells that investment for a higher price than its adjusted cost basis, and will generally realize a capital loss if it sells that investment for a lower price than its adjusted cost basis. Capital gains and losses are either short-term or long-term, depending on whether the fund holds the securities for one year or less (short-term) or more than one year (long-term).

Mutual funds make payments of fund earnings to shareholders, distributing them among all shareholders of the fund. As a shareholder, you are entitled to your portion of a fund's distributed income, including capital gains. Reinvesting your distributions buys you more shares of a fund — which lets you take advantage of the potential for compound growth. Putting the money you earn back into your investment means it, in turn, may earn even more money (or be exposed to additional losses, if the Fund earns a negative return). Over time, the power of compounding has the potential to significantly increase the value of your investment. There is no assurance, however, that you'll earn more money if you reinvest your distributions rather than receive them in cash.

The Fund intends to pay out, in the form of distributions to shareholders, a sufficient amount of its income and gains so that the Fund will qualify for treatment as a regulated investment company and generally will not have to pay any federal excise tax. The Fund generally intends to distribute any net realized capital gain (whether long-term or short-term gain) at least once a year. Normally, the Fund will declare and pay distributions of net investment income according to the following schedule:

Declaration and Distribution Schedule
Declarations	Semiannually
Distributions	Semiannually

The Fund may declare or pay distributions of net investment income more frequently.

Different share classes of the Fund usually pay different net investment income distribution amounts, because each class has different expenses. Each time a distribution is made, the NAV per share of the share class is reduced by the amount of the distribution.

The Fund generally pays cash distributions within five business days after the distribution was declared (or, if the Fund declares distributions daily, within five business days after the end of the month in which the distribution was declared). If you sell all of your shares after the record date, but before the payment date, for a distribution, you'll normally receive that distribution in cash within five business days after the sale was made.

The Fund will automatically reinvest distributions in additional shares of the same share class of the Fund unless you inform us you want to receive your distributions in cash (the financial intermediary through which you purchased shares may have different policies). You can do this by contacting the Funds at the addresses and telephone numbers listed at the beginning of the section entitled Choosing a Share Class. No sales charges apply to the purchase or sale of such shares.

For accounts held directly with the Fund (through the Transfer Agent), distributions of $10 or less will automatically be reinvested in additional Fund shares only. If you elect to receive distributions by check and the check is returned as undeliverable, all subsequent distributions will be reinvested in additional shares of the Fund.

Unless you are a tax-exempt investor or holding Fund shares through a tax-advantaged account (such as a 401(k) plan or IRA), you should consider avoiding buying Fund shares shortly before the Fund makes a distribution (other than distributions of net investment income that are declared daily) of net investment income or net realized capital gain, because doing so can cost you money in taxes to the extent the distribution consists of taxable income or gains. This is because you will, in effect, receive part of your purchase price back in the distribution. This is known as

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Columbia Acorn International®

Distributions and Taxes (continued)

“buying a dividend.” To avoid “buying a dividend,” before you invest check the Fund's distribution schedule, which is available at the Funds' website and/or by calling the Funds' telephone number listed at the beginning of the section entitled Choosing a Share Class.

Taxes

You should be aware of the following considerations applicable to the Fund:

■ The Fund intends to qualify and to be eligible for treatment each year as a regulated investment company. A regulated investment company generally is not subject to tax at the fund level on income and gains from investments that are distributed to shareholders. However, the Fund's failure to qualify for treatment as a regulated investment company would result in Fund-level taxation, and consequently, a reduction in income available for distribution to you and in the NAV of your shares. Even if the Fund qualifies for treatment as a regulated investment company, the Fund may be subject to federal excise tax on certain undistributed income or gains.

■ Otherwise taxable distributions generally are taxable to you when paid, whether they are paid in cash or automatically reinvested in additional Fund shares. Dividends paid in January are deemed paid on December 31 of the prior year if the dividend was declared and payable to shareholders of record in October, November, or December of such prior year.

■ Distributions of the Fund's ordinary income and net short-term capital gain, if any, generally are taxable to you as ordinary income. Distributions of the Fund's net long-term capital gain, if any, generally are taxable to you as long-term capital gain. Whether capital gains are long-term or short-term is determined by how long the Fund has owned the investments that generated them, rather than how long you have owned your shares. Certain events may require the Fund to sell significant amounts of appreciated securities, and make large capital gain dividends relative to the Fund’s NAV. Such events may include large net shareholder redemptions, portfolio re-balancing or fund mergers. The Fund generally provides estimates of expected capital gain dividends (if any) prior to the distribution on columbiathreadneedleus.com.

■ From time to time, a distribution from the Fund could constitute a return of capital. A return of capital is a return of an amount of your original investment and is not a distribution of income or capital gain from the Fund. Therefore, a return of capital is not taxable to you so long as the amount of the distribution does not exceed your tax basis in your Fund shares. A return of capital reduces your tax basis in your Fund shares, with any amounts exceeding such basis generally taxable as capital gain.

■ If you are an individual and you meet certain holding period and other requirements for your Fund shares, a portion of your distributions may be treated as “qualified dividend income” taxable at the lower net long-term capital gain rates instead of the higher ordinary income rates. Qualified dividend income is income attributable to the Fund's dividends received from certain U.S. and foreign corporations, as long as the Fund meets certain holding period and other requirements for the stock producing such dividends.

■ Certain high-income individuals (as well as estates and trusts) are subject to a 3.8% tax on net investment income. For individuals, the 3.8% tax applies to the lesser of (1) the amount (if any) by which the taxpayer's modified adjusted gross income exceeds certain threshold amounts or (2) the taxpayer's “net investment income.”

■ Certain derivative instruments when held in the Fund's portfolio subject the Fund to special tax rules, the effect of which may be to, among other things, accelerate income to the Fund, defer Fund losses, cause adjustments in the holding periods of Fund portfolio securities, or convert capital gains into ordinary income, short-term capital losses into long-term capital losses or long-term capital gains into short-term capital gains. These rules could therefore affect the amount, timing and/or character of distributions to shareholders.

■ Generally, a Fund realizes a capital gain or loss on an option when the option expires, or when it is exercised, sold or otherwise terminated. However, if an option is a “section 1256 contract,” which includes most traded options on a broad-based index, and the Fund holds such option at the end of its taxable year, the Fund is deemed to sell such option at fair market value at such time and recognize any gain or loss thereon, which is generally deemed to be 60% long-term and 40% short-term capital gain or loss, as described further in the SAI.

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Columbia Acorn International®

Distributions and Taxes (continued)

■ Income and proceeds received by the Fund from sources within foreign countries may be subject to foreign taxes. If at the end of the taxable year more than 50% of the value of the Fund's assets consists of securities of foreign corporations, and the Fund makes a special election, you will generally be required to include in your income for U.S. federal income tax purposes your share of the qualifying foreign income taxes paid by the Fund in respect of its foreign portfolio securities. You may be able to claim a foreign tax credit or deduction in respect of this amount, subject to certain limitations. There is no assurance that the Fund will make this election for a taxable year, even if it is eligible to do so.

■ A sale, redemption or exchange of Fund shares is a taxable event. This includes redemptions where you are paid in securities. Your sales, redemptions and exchanges of Fund shares (including those paid in securities) usually will result in a taxable capital gain or loss to you, equal to the difference between the amount you receive for your shares (or are deemed to have received in the case of exchanges) and your adjusted tax basis in the shares, which is generally the amount you paid (or are deemed to have paid in the case of exchanges) for them. Any such capital gain or loss generally will be long-term capital gain or loss if you have held your Fund shares for more than one year at the time of sale or exchange. In certain circumstances, capital losses may be converted from short-term to long-term; in other circumstances, capital losses may be disallowed under the “wash sale” rules.

■ For sales, redemptions and exchanges of shares that were acquired in a non-qualified account after 2011, the Fund generally is required to report to shareholders and the Internal Revenue Service (IRS) cost basis information with respect to those shares. The Fund uses average cost basis as its default method of calculating cost basis. For more information regarding average cost basis reporting, other available cost basis methods, and selecting or changing to a different cost basis method, please see the SAI, columbiathreadneedleus.com, or contact the Fund at 800.345.6611. If you hold Fund shares through a financial intermediary (e.g., a brokerage firm), you should contact your financial intermediary to learn about its cost basis reporting default method and the reporting elections available to your account.

■ The Fund is required by federal law to withhold tax on any taxable or tax-exempt distributions and redemption proceeds paid to you (including amounts paid to you in securities and amounts deemed to be paid to you upon an exchange of shares) if: you have not provided a correct TIN or have not certified to the Fund that withholding does not apply, the IRS has notified us that the TIN listed on your account is incorrect according to its records, or the IRS informs the Fund that you are otherwise subject to backup withholding.

 FUNDamentals

Taxes

The information provided above is only a summary of how U.S. federal income taxes may affect your investment in the Fund. It is not intended as a substitute for careful tax planning. Your investment in the Fund may have other tax implications. It does not apply to certain types of investors who may be subject to special rules, including foreign or tax-exempt investors or those holding Fund shares through a tax-advantaged account, such as a 401(k) plan or IRA. Please see the SAI for more detailed tax information. You should consult with your own tax advisor about the particular tax consequences to you of an investment in the Fund, including the effect of any foreign, state and local taxes, and the effect of possible changes in applicable tax laws.

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Columbia Acorn International®

Financial Highlights

The financial highlights table is intended to help you understand the Fund’s financial performance for the past five fiscal years. Certain information reflects financial results for a single Fund share. Per share net investment income (loss) amounts are calculated based on average shares outstanding during the period. The total return in the table represents the rate that an investor would have earned (or lost) on an investment in the Fund assuming all dividends and distributions had been reinvested. Total return does not reflect payment of sales charges, if any. Total return and portfolio turnover are not annualized for periods of less than one year. The portfolio turnover rate is calculated without regard to purchase and sales transactions of short-term instruments and certain derivatives, if any. If such transactions were included, the Fund’s portfolio turnover rate might be higher. The names of certain share classes may have changed during the periods shown below (see Appendix S to the SAI for details). This information has been audited by PricewaterhouseCoopers LLP, an independent registered public accounting firm, whose report, along with the Fund’s financial statements, is included in the Fund’s annual report, which is available upon request. The independent registered public accounting firm’s report and the Fund’s financial statements are also incorporated by reference into the SAI.

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Columbia Acorn International®

Financial Highlights (continued)

	Net asset value, beginning of period	Net investment income (loss)	Net realized and unrealized gain (loss)	Total from investment operations	Distributions from net investment income	Distributions from net realized gains	Total distributions to shareholders
Class A
Year Ended 12/31/2021	$34.31	0.01	4.08	4.09	(0.38)	(4.83)	(5.21)
Year Ended 12/31/2020	$34.20	0.06	4.51	4.57	(0.20)	(4.26)	(4.46)
Year Ended 12/31/2019	$29.48	0.25	8.19	8.44	(0.65)	(3.07)	(3.72)
Year Ended 12/31/2018	$46.51	0.23	(7.41)	(7.18)	(0.29)	(9.56)	(9.85)
Year Ended 12/31/2017	$37.71	0.25	11.71	11.96	(0.67)	(2.49)	(3.16)
Advisor Class
Year Ended 12/31/2021	$34.95	0.05	4.20	4.25	(0.55)	(4.83)	(5.38)
Year Ended 12/31/2020	$34.67	0.16	4.58	4.74	(0.20)	(4.26)	(4.46)
Year Ended 12/31/2019	$29.84	0.33	8.30	8.63	(0.73)	(3.07)	(3.80)
Year Ended 12/31/2018	$46.95	0.46	(7.61)	(7.15)	(0.40)	(9.56)	(9.96)
Year Ended 12/31/2017	$38.03	0.36	11.82	12.18	(0.77)	(2.49)	(3.26)
Class C
Year Ended 12/31/2021	$31.43	(0.24)	3.72	3.48	(0.01)	(4.83)	(4.84)
Year Ended 12/31/2020	$31.92	(0.17)	4.14	3.97	(0.20)	(4.26)	(4.46)
Year Ended 12/31/2019	$27.63	0.00(e)	7.65	7.65	(0.29)	(3.07)	(3.36)
Year Ended 12/31/2018	$44.57	(0.05)	(7.09)	(7.14)	(0.24)	(9.56)	(9.80)
Year Ended 12/31/2017	$36.18	(0.06)	11.20	11.14	(0.26)	(2.49)	(2.75)
Institutional Class
Year Ended 12/31/2021	$34.47	0.10	4.09	4.19	(0.55)	(4.83)	(5.38)
Year Ended 12/31/2020	$34.25	0.14	4.54	4.68	(0.20)	(4.26)	(4.46)
Year Ended 12/31/2019	$29.51	0.33	8.21	8.54	(0.73)	(3.07)	(3.80)
Year Ended 12/31/2018	$46.57	0.34	(7.44)	(7.10)	(0.40)	(9.56)	(9.96)
Year Ended 12/31/2017	$37.74	0.37	11.73	12.10	(0.78)	(2.49)	(3.27)
Institutional 2 Class
Year Ended 12/31/2021	$34.46	0.12	4.09	4.21	(0.59)	(4.83)	(5.42)
Year Ended 12/31/2020	$34.22	0.16	4.54	4.70	(0.20)	(4.26)	(4.46)
Year Ended 12/31/2019	$29.49	0.35	8.20	8.55	(0.75)	(3.07)	(3.82)
Year Ended 12/31/2018	$46.54	0.37	(7.43)	(7.06)	(0.43)	(9.56)	(9.99)
Year Ended 12/31/2017	$37.72	0.38	11.72	12.10	(0.79)	(2.49)	(3.28)
Institutional 3 Class
Year Ended 12/31/2021	$34.99	0.15	4.14	4.29	(0.62)	(4.83)	(5.45)
Year Ended 12/31/2020	$34.67	0.19	4.59	4.78	(0.20)	(4.26)	(4.46)
Year Ended 12/31/2019	$29.83	0.37	8.30	8.67	(0.76)	(3.07)	(3.83)
Year Ended 12/31/2018	$46.95	0.51	(7.62)	(7.11)	(0.45)	(9.56)	(10.01)
Year Ended 12/31/2017	$38.02	0.40	11.83	12.23	(0.81)	(2.49)	(3.30)
Class R
Year Ended 12/31/2021	$34.24	(0.08)	4.07	3.99	(0.21)	(4.83)	(5.04)
Year Ended 12/31/2020	$34.22	(0.01)	4.49	4.48	(0.20)	(4.26)	(4.46)
Year Ended 12/31/2019	$29.44	0.06	8.27	8.33	(0.48)	(3.07)	(3.55)
Year Ended 12/31/2018	$46.51	0.12	(7.39)	(7.27)	(0.24)	(9.56)	(9.80)
Year Ended 12/31/2017	$37.71	0.21	11.63	11.84	(0.55)	(2.49)	(3.04)

Notes to Financial Highlights
(a)	In addition to the fees and expenses that the Fund bears directly, the Fund indirectly bears a pro rata share of the fees and expenses of any other funds in which it invests, if any. Such indirect expenses are not included in the Fund's reported expense ratios.
(b)	Had the Investment Manager and/or Transfer Agent not waived fees and/or reimbursed a portion of expenses, total return would have been reduced.
(c)	The benefits derived from expense reductions had an impact of less than 0.01%.
(d)	Ratios include line of credit interest expense which is less than 0.01%.
(e)	Rounds to zero.

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Financial Highlights (continued)

	Net asset value, end of period	Total return	Total gross expense ratio to average net assets(a)	Total net expense ratio to average net assets(a)	Net investment income (loss) ratio to average net assets	Portfolio turnover	Net assets, end of period (000's)
Class A
Year Ended 12/31/2021	$33.19	12.63% (b)	1.24%	1.23% (c)	0.03%	27%	$282,125
Year Ended 12/31/2020	$34.31	14.68% (b)	1.28% (d)	1.24% (c), (d)	0.21%	55%	$283,478
Year Ended 12/31/2019	$34.20	29.56% (b)	1.27% (d)	1.24% (c), (d)	0.76%	32%	$307,872
Year Ended 12/31/2018	$29.48	(16.13%) (b)	1.25% (d)	1.24% (c), (d)	0.51%	32%	$296,349
Year Ended 12/31/2017	$46.51	31.91%	1.23%	1.20% (c)	0.56%	37%	$465,830
Advisor Class
Year Ended 12/31/2021	$33.82	12.88% (b)	0.99%	0.98% (c)	0.14%	27%	$9,279
Year Ended 12/31/2020	$34.95	14.98% (b)	1.03% (d)	0.99% (c), (d)	0.52%	55%	$22,549
Year Ended 12/31/2019	$34.67	29.86% (b)	1.02% (d)	0.99% (c), (d)	1.00%	32%	$12,733
Year Ended 12/31/2018	$29.84	(15.90%) (b)	1.00% (d)	0.99% (c), (d)	0.97%	32%	$12,740
Year Ended 12/31/2017	$46.95	32.21%	0.98%	0.98% (c)	0.81%	37%	$99,578
Class C
Year Ended 12/31/2021	$30.07	11.76% (b)	1.99%	1.98% (c)	(0.74%)	27%	$10,687
Year Ended 12/31/2020	$31.43	13.82% (b)	2.02% (d)	1.99% (c), (d)	(0.57%)	55%	$19,998
Year Ended 12/31/2019	$31.92	28.61% (b)	2.02% (d)	2.00% (c), (d)	0.01%	32%	$18,749
Year Ended 12/31/2018	$27.63	(16.76%) (b)	2.00% (d)	1.99% (c), (d)	(0.11%)	32%	$22,817
Year Ended 12/31/2017	$44.57	30.93%	1.98%	1.97% (c)	(0.15%)	37%	$63,787
Institutional Class
Year Ended 12/31/2021	$33.28	12.89% (b)	0.99%	0.98% (c)	0.28%	27%	$1,727,042
Year Ended 12/31/2020	$34.47	14.99% (b)	1.03% (d)	0.99% (c), (d)	0.46%	55%	$1,760,927
Year Ended 12/31/2019	$34.25	29.89% (b)	1.02% (d)	0.99% (c), (d)	1.01%	32%	$1,947,995
Year Ended 12/31/2018	$29.51	(15.93%) (b)	1.00% (d)	0.99% (c), (d)	0.76%	32%	$1,824,055
Year Ended 12/31/2017	$46.57	32.24%	0.98%	0.98% (c)	0.85%	37%	$3,116,383
Institutional 2 Class
Year Ended 12/31/2021	$33.25	12.97% (b)	0.95%	0.92%	0.34%	27%	$126,973
Year Ended 12/31/2020	$34.46	15.06% (b)	0.97% (d)	0.92% (d)	0.53%	55%	$129,576
Year Ended 12/31/2019	$34.22	29.95% (b)	0.97% (d)	0.93% (d)	1.06%	32%	$183,763
Year Ended 12/31/2018	$29.49	(15.85%) (b)	0.93% (d)	0.93% (d)	0.81%	32%	$160,488
Year Ended 12/31/2017	$46.54	32.27%	0.93%	0.93%	0.87%	37%	$422,916
Institutional 3 Class
Year Ended 12/31/2021	$33.83	13.00% (b)	0.90%	0.88%	0.40%	27%	$179,991
Year Ended 12/31/2020	$34.99	15.10% (b)	0.93% (d)	0.88% (d)	0.60%	55%	$277,614
Year Ended 12/31/2019	$34.67	30.04% (b)	0.92% (d)	0.89% (d)	1.12%	32%	$239,441
Year Ended 12/31/2018	$29.83	(15.82%) (b)	0.88% (d)	0.88% (d)	1.10%	32%	$198,933
Year Ended 12/31/2017	$46.95	32.36%	0.88%	0.88%	0.89%	37%	$725,247
Class R
Year Ended 12/31/2021	$33.19	12.34% (b)	1.49%	1.48% (c)	(0.22%)	27%	$3,691
Year Ended 12/31/2020	$34.24	14.40% (b)	1.53% (d)	1.49% (c), (d)	(0.04%)	55%	$3,398
Year Ended 12/31/2019	$34.22	29.21% (b)	1.52% (d)	1.50% (c), (d)	0.19%	32%	$3,696
Year Ended 12/31/2018	$29.44	(16.32%) (b)	1.50% (d)	1.49% (c), (d)	0.26%	32%	$10,049
Year Ended 12/31/2017	$46.51	31.58%	1.49%	1.48% (c)	0.46%	37%	$13,218

Prospectus 2022 67

Columbia Acorn International®

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges

As noted in the Choosing a Share Class section of the prospectus, the sales charge reductions and waivers available to investors who purchase and hold their Fund shares through different financial intermediaries may vary. This Appendix A describes financial intermediary-specific reductions and/or waiver policies applicable to Fund shares purchased and held through the particular financial intermediary. A reduction and/or waiver that is specific to a particular financial intermediary is not available to Direct-at-Fund Accounts and does not apply in any case to non-omnibus positions wherever held. These reductions and/or waivers may apply to purchases, sales, and exchanges of Fund shares. A shareholder transacting in Fund shares through a financial intermediary identified below should carefully read the terms and conditions of the reductions and/or waivers. Please consult your financial intermediary with respect to any sales charge reduction/waiver described below.

The financial intermediary-specific information below may be provided by, or compiled from or based on information provided by, the financial intermediaries noted. While the Funds, the Investment Manager and the Distributor do not establish these financial intermediary-specific policies, our representatives are available to answer questions about these financial intermediary-specific policies and can direct you to the financial intermediary if you need help understanding them.

 Ameriprise Financial Services, LLC (Ameriprise Financial Services)

The following information has been provided by Ameriprise Financial Services:

Class A Shares Front-End Sales Charge Waivers Available at Ameriprise Financial Services:

The following information applies to Class A shares purchases if you have an account with or otherwise purchase Fund shares through Ameriprise Financial Services:

Shareholders purchasing Fund shares through an Ameriprise Financial Services brokerage account are eligible for the following front-end sales charge waivers, which may differ from those disclosed elsewhere in this prospectus or the Fund’s SAI:

■ Employer-sponsored retirement plans (e.g., 401(k) plans, 457 plans, employer-sponsored 403(b) plans, profit sharing and money purchase pension plans and defined benefit plans). For purposes of this provision, employer-sponsored retirement plans do not include SEP IRAs, Simple IRAs or SAR-SEPs.

■ Shares purchased through reinvestment of capital gains distributions and dividend reinvestment when purchasing shares of the same fund (but not any other fund within the Columbia Fund family).

■ Shares exchanged from Class C shares of the same fund in the month of or following the 7-year anniversary of the purchase date. To the extent that the Fund’s Class C Shares – Conversion to Class A Shares policy (stated outside this Appendix A) provides for a waiver with respect to exchanges of Class C shares or the conversion of Class C shares following a shorter holding period, that waiver will apply.

■ Employees and registered representatives of Ameriprise Financial Services or its affiliates and their immediate family members.

■ Shares purchased by or through qualified accounts (including IRAs, Coverdell Education Savings Accounts, 401(k)s, 403(b) TSCAs subject to ERISA and defined benefit plans) that are held by a covered family member, defined as an Ameriprise financial advisor and/or the advisor’s spouse, advisor’s lineal ascendant (mother, father, grandmother, grandfather, great grandmother, great grandfather), advisor’s lineal descendant (son, step-son, daughter, step-daughter, grandson, granddaughter, great grandson, great granddaughter) or any spouse of a covered family member who is a lineal descendant.

■ Shares purchased from the proceeds of redemptions from another fund in the Columbia Fund family, provided (1) the repurchase occurs within 90 days following the redemption, (2) the redemption and purchase occur in the same account, and (3) redeemed shares were subject to a front-end or deferred sales load (i.e. Rights of Reinstatement).

A-1 Prospectus 2022

Columbia Acorn International®

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

 Robert W. Baird & Co. Incorporated (Baird)

The following information has been provided by Baird:

Effective June 30, 2020, shareholders purchasing Columbia Fund shares through a Baird platform or account that maintains an omnibus position with the Fund will only be eligible for the following sales charge waivers (front-end sales charge waivers and CDSC waivers) and discounts, which may differ from those disclosed elsewhere in this prospectus or the Fund’s SAI. A reduction and/or waiver that is specific to Baird will not apply to non-omnibus positions.

Front-End Sales Charge Waivers on Class A Shares Available at Baird:

■ Shares purchased through reinvestment of capital gains distributions and dividend reinvestment when purchasing shares of the same Columbia Fund.

■ Share purchases by employees and registered representatives of Baird or its affiliates and their family members as designated by Baird.

■ Shares purchased with the proceeds of redemptions from another Columbia Fund, provided (1) the repurchase occurs within 90 days following the redemption, (2) the redemption and purchase occur in the same accounts, and (3) redeemed shares were subject to a front-end or deferred sales charge (known as rights of reinstatement).

■ A shareholder in the Fund’s Class C shares will have their shares converted at net asset value to Class A shares of the same Columbia Fund if the shares are no longer subject to CDSC and the conversion is in line with the policies and procedures of Baird.

■ Employer-sponsored retirement plans or charitable accounts in a transactional brokerage account at Baird, including 401(k) plans, 457 plans, employer-sponsored 403(b) plans, profit sharing and money purchase pension plans and defined benefit plans. For purposes of this provision, employer-sponsored retirement plans do not include SEP IRAs, Simple IRAs or SAR-SEPs.

CDSC Waivers on Class A and Class C Shares Available at Baird:

■ Shares sold due to death or disability of the shareholder.

■ Shares sold as part of a systematic withdrawal plan as described in this prospectus.

■ Shares purchased due to returns of excess contributions from an IRA account.

■ Shares sold as part of a required minimum distribution for IRA and retirement accounts due to the shareholder reaching the qualified age based on applicable IRS regulations.

■ Shares sold to pay Baird fees but only if the transaction is initiated by Baird.

■ Shares acquired through a right of reinstatement.

Front-End Sales Charge Discounts Available at Baird: Breakpoints and/or Rights of Accumulations:

■ Breakpoints as described in this prospectus.

■ Rights of accumulations which entitle shareholders to breakpoint discounts will be automatically calculated based on the aggregated holding of Columbia Fund assets held by accounts within the purchaser’s household at Baird. Eligible Columbia Fund assets not held at Baird may be included in the rights of accumulations calculation only if the shareholder notifies his or her financial advisor about such assets.

■ Letters of Intent (LOI) allow for breakpoint discounts based on anticipated purchases of Columbia Funds through Baird, over a 13-month period of time.

Prospectus 2022 A-2

Columbia Acorn International®

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

 Edward D. Jones & Co., L.P. (Edward Jones)

Policies Regarding Transactions Through Edward Jones

The following information has been provided by Edward Jones:

Effective on or after January 15, 2021, the following information supersedes prior information with respect to transactions and positions held in Columbia Fund shares through an Edward Jones system. Clients of Edward Jones (also referred to as "shareholders") purchasing Columbia Fund shares on the Edward Jones commission and fee-based platforms are eligible only for the following sales charge discounts (also referred to as "breakpoints") and waivers, which can differ from discounts and waivers described elsewhere in this prospectus or the Fund’s SAI or through another broker-dealer. In all instances, it is the shareholder's responsibility to inform Edward Jones at the time of purchase of any relationship, holdings of Columbia Funds and Future Scholars Program, or other facts qualifying the purchaser for discounts or waivers. Edward Jones can ask for documentation of such circumstance. Shareholders should contact Edward Jones if they have questions regarding their eligibility for these discounts and waivers.

Breakpoints

■ Breakpoint pricing, otherwise known as volume pricing, at dollar thresholds as described in this prospectus.

Rights of Accumulation (ROA)

■ The applicable sales charge on a purchase of Class A shares is determined by taking into account all share classes (except certain money market funds and any assets held in group retirement plans) of Columbia Funds and Future Scholars Program held by the shareholder or in an account grouped by Edward Jones with other accounts for the purpose of providing certain pricing considerations ("pricing groups"). If grouping assets as a shareholder, this includes all share classes held on the Edward Jones platform and/or held on another platform. The inclusion of eligible Columbia Fund assets in the ROA calculation is dependent on the shareholder notifying Edward Jones of such assets at the time of calculation. Money market funds are included only if such shares were sold with a sales charge at the time of purchase or acquired in exchange for shares purchased with a sales charge.

■ The employer maintaining a SEP IRA plan and/or SIMPLE IRA plan may elect to establish or change ROA for the IRA accounts associated with the plan to a plan-level grouping as opposed to including all share classes at a shareholder or pricing group level.

■ ROA is determined by calculating the higher of cost minus redemptions or market value (current shares x NAV).

Letter of Intent (LOI)

■ Through a LOI, shareholders can receive the sales charge and breakpoint discounts for purchases shareholders intend to make over a 13-month period from the date Edward Jones receives the LOI. The LOI is determined by calculating the higher of cost or market value of qualifying holdings at LOI initiation in combination with the value that the shareholder intends to buy over a 13-month period to calculate the front-end sales charge and any breakpoint discounts. Each purchase the shareholder makes during that 13-month period will receive the sales charge and breakpoint discount that applies to the total amount. The inclusion of eligible Columbia Fund assets in the LOI calculation is dependent on the shareholder notifying Edward Jones of such assets at the time of calculation. Purchases made before the LOI is received by Edward Jones are not adjusted under the LOI and will not reduce the sales charge previously paid. Sales charges will be adjusted if LOI is not met.

■ If the employer maintaining a SEP IRA plan and/or SIMPLE IRA plan has elected to establish or change ROA for the IRA accounts associated with the plan to a plan-level grouping, LOIs will also be at the plan-level and may only be established by the employer.

A-3 Prospectus 2022

Columbia Acorn International®

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

Sales Charge Waivers

Sales charges are waived for the following shareholders and in the following situations:

■ Associates of Edward Jones and its affiliates and their family members who are in the same pricing group (as determined by Edward Jones under its policies and procedures) as the associate. This waiver will continue for the remainder of the associate's life if the associate retires from Edward Jones in good-standing and remains in good standing pursuant to Edward Jones' policies and procedures.

■ Shares purchased in an Edward Jones fee-based program.

■ Shares purchased through reinvestment of capital gains distributions and dividend reinvestment.

■ Shares purchased from the proceeds of redeemed shares of Columbia Funds so long as the following conditions are met: 1) the proceeds are from the sale of shares within 60 days of the purchase, and 2) the sale and purchase are made in the same share class and the same account or the purchase is made in an individual retirement account with proceeds from liquidations in a non-retirement account.

■ Shares exchanged into Class A shares from another share class so long as the exchange is into the same fund and was initiated at the discretion of Edward Jones. Edward Jones is responsible for any remaining CDSC due to the fund company, if applicable. Any future purchases are subject to the applicable sales charge as disclosed in this prospectus.

■ Exchanges from Class C shares to Class A shares of the same fund, generally, in the 84th month following the anniversary of the purchase date or earlier at the discretion of Edward Jones.

Contingent Deferred Sales Charge (CDSC) Waivers

If the shareholder purchases shares that are subject to a CDSC and those shares are redeemed before the CDSC is expired, the shareholder is responsible to pay the CDSC except in the following conditions:

■ The death or disability of the shareholder.

■ Systematic withdrawals with up to 10% per year of the account value.

■ Return of excess contributions from an Individual Retirement Account (IRA).

■ Shares sold as part of a required minimum distribution for IRA and retirement accounts if the redemption is taken in or after the year the shareholder reaches qualified age based on applicable IRS regulations.

■ Shares sold to pay Edward Jones fees or costs in such cases where the transaction is initiated by Edward Jones.

■ Shares exchanged in an Edward Jones fee-based program.

■ Shares acquired through NAV reinstatement.

■ Shares redeemed at the discretion of Edward Jones for Minimum Balances, as described below.

Other Important Information Regarding Transactions Through Edward Jones

Minimum Purchase Amounts

■ Initial purchase minimum: $250

■ Subsequent purchase minimum: none

Minimum Balances

■ Edward Jones has the right to redeem at its discretion Fund holdings with a balance of $250 or less. The following are examples of accounts that are not included in this policy:

■ A fee-based account held on an Edward Jones platform.

■ A 529 account held on an Edward Jones platform.

■ An account with an active systematic investment plan or LOI.

Prospectus 2022 A-4

Columbia Acorn International®

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

Exchanging Share Classes

■ At any time it deems necessary, Edward Jones has the authority to exchange at NAV a shareholder's holdings in the Fund to Class A shares.

 Janney Montgomery Scott LLC (Janney)

The following information has been provided by Janney:

Effective May 1, 2020, if you purchase Columbia Fund shares through a Janney brokerage account, you will be eligible for the following load waivers (front-end sales charge waivers and CDSC, or back-end sales charge, waivers) and discounts, which may differ from those disclosed elsewhere in this prospectus or the Fund’s SAI. A reduction and/or waiver that is specific to Janney does not apply to non-omnibus positions.

Front-End Sales Charge* Waivers on Class A Shares Available at Janney

■ Shares purchased through reinvestment of capital gains distributions and dividend reinvestment when purchasing shares of the same fund (but not any other Columbia Fund).

■ Shares purchased by employees and registered representatives of Janney or its affiliates and their family members as designated by Janney.

■ Shares purchased from the proceeds of redemptions from another Columbia Fund, provided (1) the repurchase occurs within ninety (90) days following the redemption, (2) the redemption and purchase occur in the same account, and (3) redeemed shares were subject to a front-end or deferred sales load (i.e., right of reinstatement).

■ Employer-sponsored retirement plans (e.g., 401(k) plans, 457 plans, employer-sponsored 403(b) plans, profit sharing and money purchase pension plans and defined benefit plans). For purposes of this provision, employer-sponsored retirement plans do not include SEP IRAs, Simple IRAs, SAR-SEPs or Keogh plans.

■ Shares acquired through a right of reinstatement.

■ Class C shares that are no longer subject to a CDSC and are converted to Class A shares of the same fund pursuant to Janney’s policies and procedures.

CDSC Waivers on Class A and C Shares Available at Janney

■ Shares sold upon the death or disability of the shareholder.

■ Shares sold as part of a systematic withdrawal plan as described in this prospectus.

■ Shares purchased in connection with a return of excess contributions from an IRA account.

■ Shares sold as part of a required minimum distribution for IRA and retirement accounts if the redemption is taken in or after the year the shareholder reaches qualified age based on applicable IRS regulations.

■ Shares sold to pay Janney fees but only if the transaction is initiated by Janney.

■ Shares acquired through a right of reinstatement.

■ Shares exchanged into the same share class of a different fund.

Front-End Sales Charge* Discounts Available at Janney: Breakpoints, Rights of Accumulation, and/or Letters of Intent

■ Breakpoints as described in this prospectus.

■ Rights of accumulation (“ROA”), which entitle shareholders to breakpoint discounts, will be automatically calculated based on the aggregated holding of Columbia Fund assets held by accounts within the purchaser’s household at Janney. Eligible Columbia Fund assets not held at Janney may be included in the ROA calculation only if the shareholder notifies his or her financial advisor about such assets.

■ Letters of intent which allow for breakpoint discounts based on anticipated purchases within the Columbia Funds, over a 13-month time period. Eligible Columbia Fund assets not held at Janney may be included in the calculation of letters of intent only if the shareholder notifies his or her financial advisor about such assets.

A-5 Prospectus 2022

Columbia Acorn International®

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

* Also referred to as an “initial sales charge”.

 Merrill Lynch Pierce, Fenner & Smith Incorporated (Merrill Lynch)

The following information has been provided by Merrill Lynch:

Shareholders purchasing Columbia Fund shares through a Merrill Lynch platform or account will be eligible only for the following load waivers (front-end sales charge waivers and contingent deferred, or back-end, sales charge waivers) and discounts, which may differ from those disclosed elsewhere in this prospectus or the Fund’s SAI:

Front-End Load Discounts Available at Merrill Lynch:

Merrill Lynch makes available breakpoint discounts on shares of the Fund through:

■ Breakpoints as described in this prospectus.

■ Rights of Accumulation (ROA) which entitle shareholders to breakpoint discounts as described in this prospectus will be automatically calculated based on the aggregated holding of Columbia Fund assets held by accounts (including 529 program holdings, where applicable) within the purchaser’s household at Merrill Lynch. Eligible Columbia Fund assets not held at Merrill Lynch may be included in the ROA calculation only if the shareholder notifies his or her financial advisor about such assets.

■ Letters of Intent (LOI) which allow for breakpoint discounts based on anticipated purchases of Columbia Funds, through Merrill Lynch, over a 13-month period of time (if applicable).

Front-End Sales Load Waivers on Class A Shares Available at Merrill Lynch:

■ Employer-sponsored retirement, deferred compensation and employee benefit plans (including health savings accounts) and trusts used to fund those plans, provided that the shares are not held in a commission-based brokerage account and shares are held for the benefit of the plan.

■ Shares purchased by a 529 Plan (does not include 529 Plan units or 529-specific share classes or equivalents).

■ Shares purchased through a Merrill Lynch affiliated investment advisory program.

■ Shares exchanged due to the holdings moving from a Merrill Lynch affiliated investment advisory program to a Merrill Lynch brokerage (non-advisory) account pursuant to Merrill Lynch’s policies relating to sales load discounts and waivers.

■ Shares purchased by third party investment advisors on behalf of their advisory clients through Merrill Lynch’s platform.

■ Shares of funds purchased through the Merrill Edge Self-Directed platform (if applicable).

■ Shares purchased through reinvestment of capital gains distributions and dividend reinvestment when purchasing shares of the same fund (but not any other Columbia Fund).

■ Shares exchanged from Class C (i.e., level-load) shares of the same fund pursuant to Merrill Lynch’s policies relating to sales load discounts and waivers.

■ Employees and registered representatives of Merrill Lynch or its affiliates and their family members.

■ Directors or Trustees of the Fund, and employees of the Fund’s investment adviser or any of its affiliates, as described in this prospectus.

■ Eligible shares purchased from the proceeds of redemptions from another Columbia Fund, provided (1) the repurchase occurs within 90 days following the redemption, (2) the redemption and purchase occur in the same account, and (3) redeemed shares were subject to a front-end or deferred sales load (known as Rights of Reinstatement). Automated transactions (i.e. systematic purchases and withdrawals) and purchases made after shares are automatically sold to pay Merrill Lynch’s account maintenance fees are not eligible for reinstatement.

CDSC Waivers on Class A and C Shares Available at Merrill Lynch:

■ Death or disability of the shareholder.

Prospectus 2022 A-6

Columbia Acorn International®

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

■ Shares sold as part of a systematic withdrawal plan as described in this prospectus.

■ Return of excess contributions from an IRA Account.

■ Shares sold as part of a required minimum distribution for IRA and retirement accounts pursuant to the Internal Revenue Code.

■ Shares sold to pay Merrill Lynch fees but only if the transaction is initiated by Merrill Lynch.

■ Shares acquired through a right of reinstatement.

■ Shares held in retirement brokerage accounts, that are exchanged for a lower cost share class due to transfer to certain fee based accounts or platforms (applicable to Class A and Class C shares only).

■ Shares received through an exchange due to the holdings moving from a Merrill Lynch affiliated investment advisory program to a Merrill Lynch brokerage (non-advisory) account pursuant to Merrill Lynch’s policies relating to sales load discounts and waivers.

 Morgan Stanley Smith Barney, LLC (Morgan Stanley Wealth Management)

The following information has been provided by Morgan Stanley Wealth Management:

Effective July 1, 2018, shareholders purchasing Columbia Fund shares through a Morgan Stanley Wealth Management transactional brokerage account will be eligible only for the following front-end sales charge waivers with respect to Class A shares, which may differ from and may be more limited than those disclosed elsewhere in this prospectus or the Fund’s SAI.

Front-End Sales Charge Waivers on Class A Shares Available at Morgan Stanley Wealth Management Effective July 1, 2018:

■ Employer-sponsored retirement plans (e.g., 401(k) plans, 457 plans, employer-sponsored 403(b) plans, profit sharing and money purchase pension plans and defined benefit plans).  For purposes of this provision, employer-sponsored retirement plans do not include SEP IRAs, Simple IRAs, SAR-SEPs or Keogh plans.

■ Morgan Stanley employee and employee-related accounts according to Morgan Stanley’s account linking rules.

■ Shares purchased through reinvestment of dividends and capital gains distributions when purchasing shares of the same fund.

■ Shares purchased through a Morgan Stanley self-directed brokerage account.

■ Class C (i.e., level-load) shares that are no longer subject to a CDSC and are exchanged for Class A shares of the same fund pursuant to Morgan Stanley Wealth Management’s share class exchange program.

■ Shares purchased from the proceeds of redemptions from another Columbia Fund, provided (i) the repurchase occurs within 90 days following the redemption, (ii) the redemption and purchase occur in the same account, and (iii) redeemed shares were subject to a front-end or deferred sales charge.

 Raymond James & Associates, Inc., Raymond James Financial Services, Inc. and each entity’s affiliates (Raymond James)

The following information has been provided by Raymond James:

Intermediary-Defined Sales Charge Waiver Policies:

The availability of certain initial or deferred sales charge waivers and discounts may depend on the particular financial intermediary or type of account through which you purchase or hold Columbia Fund shares.

Intermediaries may have different policies and procedures regarding the availability of front-end sales load waivers or contingent deferred (back-end) sales load (CDSC) waivers, which are discussed below. In all instances, it is the purchaser’s responsibility to notify the Fund or the purchaser’s financial intermediary at the time of purchase of any

A-7 Prospectus 2022

Columbia Acorn International®

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

relationship or other facts qualifying the purchaser for sales charge waivers or discounts. For waivers and discounts not available through a particular intermediary, shareholders will have to purchase Columbia Fund shares directly from the Fund or through another intermediary to receive these waivers or discounts.

Raymond James:

Effective March 1, 2019, shareholders purchasing Columbia Fund shares through a Raymond James platform or account, or through an introducing broker-dealer or independent registered investment adviser for which Raymond James provides trade execution, clearance, and/or custody services, will be eligible only for the following load waivers (front-end sales charge waivers and contingent deferred, or back-end, sales charge waivers) and discounts, which may differ from those disclosed elsewhere in this prospectus or the Fund’s SAI.

Front-End Sales Load Waivers on Class A Shares Available at Raymond James:

■ Shares purchased in an investment advisory program.

■ Shares purchased within the Columbia Funds through a systematic reinvestment of capital gains and dividend distributions.

■ Employees and registered representatives of Raymond James or its affiliates and their family members as designated by Raymond James.

■ Shares purchased from the proceeds of redemptions within the Columbia Funds, provided (1) the repurchase occurs within 90 days following the redemption, (2) the redemption and purchase occur in the same account, and (3) redeemed shares were subject to a front-end or deferred sales load (known as Rights of Reinstatement).

■ A shareholder in the Fund’s Class C shares will have their shares converted at net asset value to Class A shares (or the appropriate share class) of the Fund if the shares are no longer subject to a CDSC and the conversion is in line with the policies and procedures of Raymond James.

CDSC Waivers on Class A and Class C Shares Available at Raymond James:

■ Death or disability of the shareholder.

■ Shares sold as part of a systematic withdrawal plan as described in this prospectus.

■ Return of excess contributions from an IRA Account.

■ Shares sold as part of a required minimum distribution for IRA and retirement accounts due to the shareholder reaching the qualified age based on applicable IRS regulations as described in this prospectus.

■ Shares sold to pay Raymond James fees but only if the transaction is initiated by Raymond James.

■ Shares acquired through a right of reinstatement.

Front-End Load Discounts Available at Raymond James: Breakpoints, Rights of Accumulation and/or Letters of Intent:

■ Breakpoints as described in this prospectus.

■ Rights of accumulation which entitle shareholders to breakpoint discounts will be automatically calculated based on the aggregated holding of Columbia Fund assets held by accounts within the purchaser’s household at Raymond James. Eligible Columbia Fund assets not held at Raymond James may be included in the calculation of rights of accumulation only if the shareholder notifies his or her financial advisor about such assets.

■ Letters of intent which allow for breakpoint discounts based on anticipated purchases within the Columbia Funds, over a 13-month time period. Eligible Columbia Fund assets not held at Raymond James may be included in the calculation of letters of intent only if the shareholder notifies his or her financial advisor about such assets.

Prospectus 2022 A-8

Columbia Acorn International®

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

 Stifel Financial Corp. (Stifel)

The following information has been provided by Stifel:

Effective June 30, 2020, Class C shares of Columbia Funds that were purchased through a Stifel platform or account that maintains an omnibus position with the Fund that are no longer subject to a CDSC are exchanged to Class A shares of the same Columbia Fund pursuant to Stifel’s policies and procedures. This does not apply to non-omnibus positions.

 U.S. Bancorp Investments, Inc. (USBI)

The following information has been provided by USBI:

Effective September of 2021, shareholders purchasing Columbia Fund shares through a USBI platform or who own shares for which USBI is the broker-dealer, where the shares are held in an omnibus account, will only be eligible for the following front-end sales charge waivers and discounts, which may differ from those disclosed elsewhere in this prospectus or the Fund’s SAI.

All other sales charge waivers and reduction described elsewhere in this prospectus or the Fund’s SAI still apply.

USBI Conversion of Class C shares

Class C (i.e., level-load) shares that are no longer subject to a contingent deferred sales charge are systematically converted to the Class A shares of the same fund pursuant to USBI’s share class exchange policy.

 Additional Sales Charge Reductions and/or Waivers Available at Certain Financial Intermediaries

Shareholders purchasing Columbia Fund shares through a platform or account of RBC Capital Markets, LLC are eligible for the following sales charge waiver:

Class A Shares Front-End Sales Charge Waiver Available at RBC Capital Markets, LLC:

■ For employer-sponsored retirement plans held through a commissionable brokerage account, Class A shares are available at NAV (i.e., without a sales charge). For this purpose, employer-sponsored retirement plans include, but are not limited to, 401(k) plans, 457 plans, employer-sponsored 403(b) plans, profit sharing and money purchase pension plans and defined benefit plans. For purposes of this provision, employer-sponsored retirement plans do not include SEP IRAs, Simple IRAs, SAR-SEPs or Keogh plans.

A-9 Prospectus 2022

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Columbia Acorn International^®

P.O. Box 219104
Kansas City, MO 64121-9104

Columbia Acorn Family of Funds

Additional Information About the Fund

Additional information about the Fund’s investments is available in the Fund’s annual and semiannual reports to shareholders. In the annual report, you will find a discussion of the market conditions and investment strategies that significantly affected the Fund’s performance during its last fiscal year. The SAI also provides additional information about the Fund and its policies. The SAI, which has been filed with the SEC, is legally part of this prospectus (incorporated by reference). To obtain these documents free of charge, to request other information about the Fund and to make shareholder inquiries, please contact the Fund as follows:

By Mail:  Columbia Management Investment Services Corp.
P.O. Box 219104
Kansas City, MO 64121-9104

By Telephone: 800.345.6611

Online: columbiathreadneedleus.com

Shareholder Communications with the Board

The Fund’s Board of Trustees has adopted procedures by which shareholders may communicate with the Board. Shareholders who wish to communicate with the Board should send their written communications to the Board by mail, c/o Columbia Wanger Asset Management, LLC, 71 S. Wacker Drive, Suite 2500, Chicago, IL 60606, Attention: Secretary. Shareholder communications must (i) be in writing, (ii) identify the Columbia Acorn Fund to which the communication relates and (iii) state the particular class of shares and number of shares held by the communicating shareholder.

Obtaining Additional Information from the SEC

Reports and other information about the Fund are also available in the EDGAR Database on the SEC’s website at http://www.sec.gov. You can receive copies of this information, for a duplication fee, by electronic request at the following e-mail address: publicinfo@sec.gov.

The investment company registration number of Columbia Acorn Trust, of which the Fund is a series, is 811-01829.

Columbia Threadneedle Investments is the global brand name of the Columbia and Threadneedle group of companies.
The Fund is distributed by Columbia Management Investment Distributors, Inc., 290 Congress Street, Boston, MA 02210.

© 2022 Columbia Management Investment Advisers, LLC. All rights reserved.

PRO111_12_M01_(05/22)

 

Prospectus

May 1, 2022

Columbia Acorn Family of Funds

Managed by Columbia Wanger Asset Management, LLC

Columbia Acorn International Select^SM

Class	Ticker Symbol
A	LAFAX
Advisor (Class Adv)	CILRX
C	LFFCX

Class	Ticker Symbol
Institutional (Class Inst)	ACFFX
Institutional 2 (Class Inst2)	CRIRX
Institutional 3 (Class Inst3)	CSIRX

 

As with all mutual funds, the Securities and Exchange Commission (SEC) has not approved or disapproved these securities or passed upon the adequacy of this prospectus. Any representation to the contrary is a criminal offense.

Table of Contents

Summary of the Fund	3
Investment Objective	3
Fees and Expenses of the Fund	3
Principal Investment Strategies	4
Principal Risks	5
Performance Information	9
Fund Management	10
Purchase and Sale of Fund Shares	11
Tax Information	11
Payments to Broker-Dealers and Other Financial Intermediaries	11
More Information About the Fund	12
Investment Objective	12
Principal Investment Strategies	12
Principal Risks	12
Additional Investment Strategies and Policies	18
Board of Trustees	23
Primary Service Provider Contracts	24
Other Roles and Relationships of Ameriprise Financial and its Affiliates — Certain Conflicts of Interest	26
Certain Legal Matters	27
Choosing a Share Class	28
The Funds	28
Summary of Share Class Features	28
Sales Charges and Commissions	34
Reductions/Waivers of Sales Charges	37
Distribution and Service Fees	41
Financial Intermediary Compensation	42
Buying, Selling and Exchanging Shares	44
Share Price Determination	44
Transaction Rules and Policies	45
Opening an Account and Placing Orders	49
Buying Shares	51
Selling Shares	56
Exchanging Shares	58
Distributions and Taxes	61
Distributions to Shareholders	61
Taxes	62
Financial Highlights	65
Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges	A-1

2

Columbia Acorn International Select^SM

Summary of the Fund

Investment Objective

Columbia Acorn International Select^SM (the Fund) seeks long-term capital appreciation.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below. You may qualify for sales charge discounts if you and members of your immediate family invest, or agree to invest in the future, at least $50,000 in certain classes of shares of eligible funds distributed by Columbia Management Investment Distributors, Inc. (the Distributor). More information is available about these and other sales charge discounts and waivers from your financial intermediary, and can be found in the Choosing a Share Class section beginning on page 28 of the Fund’s prospectus, in Appendix A to the prospectus beginning on page A-1 and in Appendix S to the Statement of Additional Information (SAI) under Sales Charge Waivers beginning on page S-1.

Shareholder Fees (fees paid directly from your investment)
	Class A	Class C	Classes Adv, Inst, Inst2 and Inst3
Maximum sales charge (load) imposed on purchases (as a % of offering price)	5.75%	None	None
Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)	1.00%(a)	1.00%(b)	None

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
	Class A	Class Adv	Class C	Class Inst	Class Inst2	Class Inst3
Management fees	0.89%	0.89%	0.89%	0.89%	0.89%	0.89%
Distribution and/or service (12b-1) fees	0.25%	0.00%	1.00%	0.00%	0.00%	0.00%
Other expenses	0.30%	0.30%	0.30%	0.30%	0.21%	0.16%
Total annual Fund operating expenses(c)	1.44%	1.19%	2.19%	1.19%	1.10%	1.05%
Less: Fee waivers and/or expense reimbursements(d)	(0.20%)	(0.20%)	(0.20%)	(0.20%)	(0.21%)	(0.21%)
Total annual Fund operating expenses after fee waivers and/or expense reimbursements	1.24%	0.99%	1.99%	0.99%	0.89%	0.84%

(a)	This charge is imposed on certain investments of between $1 million and $50 million redeemed within 18 months after purchase, as follows: 1.00% if redeemed within 12 months after purchase, and 0.50% if redeemed more than 12, but less than 18, months after purchase, with certain limited exceptions.
(b)	This charge applies to redemptions within 12 months after purchase, with certain limited exceptions.

(c)

“Total annual Fund operating expenses” include acquired fund fees and expenses (expenses the Fund incurs indirectly through its investments in other investment companies) and may be higher than the ratio of expenses to average net assets shown in the Financial Highlights section of this prospectus because the ratio of expenses to average net assets does not include acquired fund fees and expenses.

(d)

Columbia Wanger Asset Management, LLC (the Investment Manager) has contractually agreed to waive fees and reimburse certain expenses of the Fund, through April 30, 2023, so that ordinary operating expenses (excluding any transaction costs and certain other investment-related expenses, interest and fees on borrowings and expenses associated with the Fund’s investment in other investment companies, if any) do not exceed the annual rates of 1.24% for Class A shares, 0.99% for Class Adv shares, 1.99% for Class C shares, 0.99% for Class Inst shares, 0.89% for Class Inst2 shares and 0.84% for Class Inst3 shares. This arrangement may only be amended or terminated with approval from the Fund’s Board of Trustees and the Investment Manager.

Prospectus 2022 3

Columbia Acorn International Select^SM

Summary of the Fund (continued)

 Example

The following example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example illustrates the hypothetical expenses that you would incur over the time periods indicated, and assumes that:

■ you invest $10,000 in the applicable class of Fund shares for the periods indicated,

■ your investment has a 5% return each year, and

■ the Fund’s total annual operating expenses remain the same as shown in the Annual Fund Operating Expenses table above.

Since the waivers and/or reimbursements shown in the Annual Fund Operating Expenses table above expire as indicated in the preceding table, they are only reflected in the 1 year example and the first year of the other examples. Although your actual costs may be higher or lower, based on the assumptions listed above, your costs would be:

	1 year	3 years	5 years	10 years
Class A (whether or not shares are redeemed)	$694	$986	$1,299	$2,184
Class Adv (whether or not shares are redeemed)	$101	$358	$635	$1,425
Class C (assuming redemption of all shares at the end of the period)	$302	$666	$1,156	$2,318
Class C (assuming no redemption of shares)	$202	$666	$1,156	$2,318
Class Inst (whether or not shares are redeemed)	$101	$358	$635	$1,425
Class Inst2 (whether or not shares are redeemed)	$91	$329	$586	$1,321
Class Inst3 (whether or not shares are redeemed)	$86	$313	$559	$1,264

Portfolio Turnover

The Fund may pay transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 27% of the average value of its portfolio.

Principal Investment Strategies

Under normal circumstances, the Fund invests at least 65% of its net assets in foreign companies in developed markets (for example, Japan, Canada and the United Kingdom).

The Fund also may invest up to 35% of its total assets in companies in emerging markets (for example, China, India and Brazil). The Fund generally invests in at least three countries other than the United States but may invest up to 25% of its total assets in securities of U.S. issuers.

Under normal circumstances, the Fund invests a majority of its net assets in the common stock of small- and mid-sized companies with market capitalizations generally in the range of market capitalizations in the MSCI ACWI ex USA Growth Index (Net), the Fund's primary benchmark, (the Index) at the time of purchase (between $912.3 million and $2.3 trillion as of March 31, 2022). The market capitalization range and composition of companies in the Index are subject to change. As such, the size of the companies in which the Fund invests may change. The Fund determines a company’s market capitalization at the time of investment. As long as a majority of its net assets are invested in companies within the Index, the Fund may continue to hold and make new investments in a security even if the company’s market capitalization grows beyond the market capitalization of the largest company within the Index or falls below the market capitalization of the smallest company within the Index. 

4 Prospectus 2022

Columbia Acorn International Select^SM

Summary of the Fund (continued)

Columbia Wanger Asset Management, LLC, the Fund's investment adviser (the Investment Manager), believes that stocks of small- and mid-sized companies, which generally are not as well known by financial analysts as larger companies, may offer higher return potential than stocks of larger companies. The Fund also may invest in larger-sized companies. The Investment Manager from time to time emphasizes one or more sectors in selecting the Fund’s investments, including the health care, industrials, and information technology sectors. 

The Fund invests in a limited number of foreign companies (generally between 30-60), offering the potential to provide above-average growth over time. In pursuit of the Fund’s objective, the portfolio managers will take advantage of the research and stock-picking capabilities of the Investment Manager and will generally concentrate the Fund’s investments in those sectors, companies, geographic regions or industries that the portfolio managers believe offer the best investment return potential. 

The Investment Manager typically seeks companies with: 

■ A strong business franchise that offers growth potential. 

■ Products and services in which the company has a competitive advantage. 

■ A stock price the Investment Manager believes is reasonable relative to the assets and earning power of the company. 

The Investment Manager may sell a portfolio holding if the security reaches the Investment Manager's price target, if the company has a deterioration of fundamentals, such as failing to meet key operating benchmarks, or if the Investment Manager believes other securities are more attractive. The Investment Manager also may sell a portfolio holding to fund redemptions. 

Principal Risks

An investment in the Fund involves risks, including those described below, among others. There is no assurance that the Fund will achieve its investment objective and you may lose money. The value of the Fund’s holdings may decline, and the Fund’s net asset value (NAV) and share price may go down. An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Active Management Risk. The Investment Manager’s active management of the Fund could cause the Fund to underperform its benchmark index and/or other funds with similar investment objectives and/or strategies.

Market Risk. The Fund may incur losses due to declines in the value of one or more securities in which it invests. These declines may be due to factors affecting a particular issuer, or the result of, among other things, political, regulatory, market, economic or social developments affecting the relevant market(s) more generally. In addition, turbulence in financial markets and reduced liquidity in equity, credit and/or fixed income markets may negatively affect many issuers, which could adversely affect the Fund’s ability to price or value hard-to-value assets in thinly traded and closed markets and could cause significant redemptions and operational challenges. Global economies and financial markets are increasingly interconnected, and conditions and events in one country, region or financial market may adversely impact issuers in a different country, region or financial market. These risks may be magnified if certain events or developments adversely interrupt the global supply chain; in these and other circumstances, such risks might affect companies worldwide. As a result, local, regional or global events such as terrorism, war, other conflicts, natural disasters, disease/virus outbreaks and epidemics or other public health issues, recessions, depressions or other events – or the potential for such events – could have a significant negative impact on global economic and market conditions. 

The large-scale invasion of Ukraine by Russia in February 2022 has resulted in sanctions and market disruptions including declines in regional and global stock and commodity markets and significant devaluations of Russian currency. The extent and duration of the military action are impossible to predict but could be significant. Market disruption caused by the Russian military action, and any counter measures or responses thereto (including international sanctions, a downgrade in the country’s credit rating, purchasing and financing restrictions, boycotts, tariffs, changes in consumer or purchaser preferences, cyberattacks and espionage) could have severe adverse impacts on regional and/or global securities and commodities markets, including markets for oil and natural gas. 

Prospectus 2022 5

Columbia Acorn International Select^SM

Summary of the Fund (continued)

These impacts may include reduced market liquidity, distress in credit markets, further disruption of global supply chains, increased risk of inflation, and limited access to investments in certain international markets and/or issuers. These developments and other related events could negatively impact Fund performance. 

The pandemic caused by coronavirus disease 2019 and its variants (COVID-19) has resulted in, and may continue to result in, significant global economic and societal disruption and market volatility due to disruptions in market access, resource availability, facilities operations, imposition of tariffs, export controls and supply chain disruption, among others. Such disruptions may be caused, or exacerbated by, quarantines and travel restrictions, workforce displacement and loss in human and other resources. The uncertainty surrounding the magnitude, duration, reach, costs and effects of the global pandemic, as well as actions that have been or could be taken by governmental authorities or other third parties, present unknowns that are yet to unfold. The impacts, as well as the uncertainty over impacts to come, of COVID-19 – and any other infectious illness outbreaks, epidemics and pandemics that may arise in the future – could negatively affect global economies and markets in ways that cannot necessarily be foreseen. In addition, the impact of infectious illness outbreaks and epidemics in less developed countries may be greater due to generally less established healthcare systems, governments and financial markets. Public health crises caused by the COVID-19 outbreak may exacerbate other pre-existing political, social and economic risks in certain countries or globally. The disruptions caused by COVID-19 could prevent the Fund from executing advantageous investment decisions in a timely manner and negatively impact the Fund’s ability to achieve its investment objective. Any such events could have a significant adverse impact on the value and risk profile of the Fund. 

Sector Risk. At times, the Fund may have a significant portion of its assets invested in securities of companies conducting business within one or more economic sectors, including the health care, industrials, and information technology sectors. Companies in the same sector may be similarly affected by economic, regulatory, political or market events or conditions, which may make the Fund more vulnerable to unfavorable developments in that sector than funds that invest more broadly. Generally, the more broadly the Fund invests, the more it spreads risk and potentially reduces the risks of loss and volatility. 

■ Health Care Sector. The Fund is more susceptible to the particular risks that may affect companies in the health care sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the health care sector are subject to certain risks, including restrictions on government reimbursement for medical expenses, government approval of medical products and services, competitive pricing pressures, and the rising cost of medical products and services (especially for companies dependent upon a relatively limited number of products or services), among others. Performance of such companies may be affected by factors including, government regulation, obtaining and protecting patents (or the failure to do so), product liability and other similar litigation as well as product obsolescence. 

■ Industrials Sector. The Fund is more susceptible to the particular risks that may affect companies in the industrials sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the industrials sector are subject to certain risks, including changes in supply and demand for their specific product or service and for industrial sector products in general, including decline in demand for such products due to rapid technological developments and frequent new product introduction. Performance of such companies may be affected by factors including government regulation, world events, economic conditions and risks for environmental damage and product liability claims. 

■ Information Technology Sector. The Fund is more susceptible to the particular risks that may affect companies in the information technology sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the information technology sector are subject to certain risks, including the risk that new services, equipment or technologies will not be accepted by consumers and businesses or will become rapidly obsolete. Performance of such companies may be affected by factors including obtaining and protecting patents (or the failure to do so) and significant competitive pressures, including aggressive pricing of their products or services, new market entrants, competition for market share and short product cycles due to an accelerated rate of technological developments. Such competitive pressures may lead to limited earnings and/or falling profit margins. As a result, the value of their securities may fall or fail to rise. In addition, many information technology sector companies have limited operating histories and prices of these companies’ securities historically have been 

6 Prospectus 2022

Columbia Acorn International Select^SM

Summary of the Fund (continued)

more volatile than other securities, especially over the short term. Some companies in the information technology sector are facing increased government and regulatory scrutiny and may be subject to adverse government or regulatory action, which could negatively impact the value of their securities. 

Select Portfolio Risk. Because the Fund may invest in a limited number of companies, the Fund as a whole is subject to greater risk of loss if any of its portfolio securities decline in price. The Fund accordingly may be more susceptible to economic, political and regulatory developments than a fund that invests in a greater number of companies. In addition, the Fund’s holdings and weightings will diverge significantly from its primary benchmark’s holdings and weightings and the Fund may therefore experience greater risk and volatility relative to the benchmark. Because the Fund may invest in more than one company concentrated in a similar industry, sector or geographic region, the Fund may be even more concentrated than the number of companies it may hold would suggest. 

Liquidity and Trading Volume Risk. Due to market conditions, including uncertainty regarding the price of a security, it may be difficult for the Fund to buy or sell portfolio securities at a desirable time or price, which could result in investment losses. This risk of portfolio illiquidity is heightened with respect to small- and mid-cap securities, generally, and foreign small- and mid-cap securities in particular. The Fund may have to lower the selling price, liquidate other investments, or forego another, more appealing investment opportunity as a result of illiquidity in the markets. The Fund may also be limited in its ability to execute favorable trades in portfolio securities in response to changes in share prices and fundamentals, and may be forced to dispose of securities under disadvantageous circumstances and at a loss. As the Fund grows in size or, conversely, if it faces significant redemption pressure, these considerations take on increasing significance and may adversely impact performance. 

Foreign Securities Risk. Investments in or exposure to securities of foreign companies may involve heightened risks relative to investments in or exposure to securities of U.S. companies. Investing in securities of foreign companies subjects the Fund to the risks associated with an issuer’s (and any of its related companies’) country of organization and places of business operations, including risks related to political, regulatory, economic, social, diplomatic and other conditions or events (including, for example, military confrontations and actions, war, other conflicts, terrorism and disease/virus outbreaks and epidemics) occurring in the country or region, as well as risks associated with less developed custody and settlement practices. Foreign securities may be more volatile and less liquid than securities of U.S. companies, and are subject to the risks associated with potential imposition of economic and other sanctions against a particular foreign country, its nationals or industries or businesses within the country. In addition, foreign governments may impose withholding or other taxes on the Fund’s income, capital gains or proceeds from the disposition of foreign securities, which could reduce the Fund’s return on such securities. 

Operational and Settlement Risks of Foreign Securities. The Fund’s foreign securities are generally held outside the United States in the primary market for the securities in the custody of foreign sub-custodians. Some countries have limited governmental oversight and regulation, which increases the risk of corruption and fraud and the possibility of losses to the Fund. In particular, under certain circumstances, foreign securities may settle on a delayed delivery basis, meaning that the Fund may be required to make payment for securities before the Fund has actually received delivery of the securities or deliver securities prior to the receipt of payment. As a result, there is a risk that the security will not be delivered to the Fund or that payment will not be received. Losses can also result from lost, stolen or counterfeit securities; defaults by brokers and banks; failures or defects of the settlement system; or poor and improper record keeping by registrars and issuers. 

Share Blocking. In certain non-U.S. markets, an issuer’s securities are blocked from trading for a specified number of days before and, in certain instances, after a shareholder meeting. The blocking period can last up to several weeks. Share blocking may prevent the Fund from buying or selling securities during this period. As a consequence of these restrictions, the Investment Manager, on behalf of the Fund, may abstain from voting proxies in markets that require share blocking. 

Emerging Market Securities Risk. Securities issued by foreign governments or companies in emerging market countries, such as China, Russia and certain countries in Eastern Europe, the Middle East, Asia, Latin America or Africa, are more likely to have greater exposure to the risks of investing in foreign securities that are described in Foreign Securities Risk. In addition, emerging market countries are more likely to experience instability resulting, for example, from rapid changes or developments in social, political, economic or other conditions. Their economies are 

Prospectus 2022 7

Columbia Acorn International Select^SM

Summary of the Fund (continued)

usually less mature and their securities markets are typically less developed with more limited trading activity (i.e., lower trading volumes and less liquidity) than more developed countries. Emerging market securities tend to be more volatile, and may be more susceptible to market manipulation, than securities in more developed markets. Many emerging market countries are heavily dependent on international trade and have fewer trading partners, which makes them more sensitive to world commodity prices and economic downturns in other countries, and some have a higher risk of currency devaluations. Due to the differences in the nature and quality of financial information of issuers of emerging market securities, including auditing and financial reporting standards, financial information and disclosures about such issuers may be unavailable or, if made available, may be considerably less reliable than publicly available information about other foreign securities. 

Operational and Settlement Risks of Securities in Emerging Markets. Foreign sub-custodians in emerging markets may be recently organized, lack extensive operating experience or lack effective government oversight or regulation. In addition, there may be legal restrictions or limitations on the ability of the Fund to recover assets held in custody by a foreign sub-custodian in the event of the bankruptcy of the sub-custodian. There may also be a greater risk that settlement may be delayed and that cash or securities of the Fund may be lost because of failures of or defects in the system, including fraud or corruption. Settlement systems in emerging markets also have a higher risk of failed trades. 

Risks Related to Currencies and Corporate Actions in Emerging Markets. Risks related to currencies and corporate actions are also greater in emerging market countries than in developed countries. Emerging market currencies may not have an active trading market and are subject to a higher risk of currency devaluations. 

Risks Related to Corporate and Securities Laws in Emerging Markets. Securities laws in emerging markets may be relatively new and unsettled and, consequently, there is a risk of rapid and unpredictable change in laws regarding foreign investment, securities regulation, title to securities and shareholder rights. 

Small- and Mid-Cap Company Securities Risk. Investments in small- and mid-cap companies often involve greater risks than investments in larger, more established companies because small- and mid-cap companies tend to have less predictable earnings and may lack the management experience, financial resources, product diversification and competitive strengths of larger companies. Securities of small- and mid-cap companies may be less liquid and more volatile than the securities of larger companies. 

Large-Cap Company Securities Risk. Larger, more established companies may be unable to respond quickly to new competitive challenges, such as changes in consumer tastes or innovative smaller competitors. Also, large-cap companies are sometimes unable to attain the high growth rates of successful, smaller companies, especially during extended periods of economic expansion. 

Geographic Focus Risk. The Fund may be particularly susceptible to risks related to economic, political, regulatory or other events or conditions affecting issuers and countries within the specific geographic regions in which the Fund invests. The Fund’s NAV may be more volatile than the NAV of a more geographically diversified fund. 

■ Asia Pacific Region. Many of the countries in the Asia Pacific region are considered underdeveloped or developing, including from a political, economic and/or social perspective, and may have relatively unstable governments and economies based on limited business, industries and/or natural resources or commodities. Events in any one country within the region may impact other countries in the region or the region as a whole. As a result, events in the region will generally have a greater effect on the Fund than if the Fund were more geographically diversified. This could result in increased volatility in the value of the Fund’s investments and losses for the Fund. Also, securities of some companies in the region can be less liquid than U.S. or other foreign securities, potentially making it difficult for the Fund to sell such securities at a desirable time and price. 

■ Europe. The Fund is particularly susceptible to risks related to economic, political, regulatory or other events or conditions, including acts of war or other conflicts in the region, affecting issuers and countries in Europe. Countries in Europe are often closely connected and interdependent, and events in one European country can have an adverse impact on, and potentially spread to, other European countries. In addition, significant private and public sectors’ debt problems of a single European Union (EU) country can pose economic risks to the EU as a whole. As a result, the Fund’s NAV may be more volatile than the NAV of a more geographically diversified fund. If securities of issuers in Europe fall out of favor, it may cause the Fund to underperform other funds that do not 

8 Prospectus 2022

Columbia Acorn International Select^SM

Summary of the Fund (continued)

focus their investments in this region of the world. The departure of the United Kingdom (UK) from the EU single market became effective January 1, 2021 with the end of the Brexit transition period and the post-Brexit trade deal between the UK and EU taking effect on December 31, 2020. The impact of any partial or complete dissolution of the EU on the UK and European economies and the broader global economy could be significant, resulting in negative impacts on currency and financial markets generally, such as increased volatility and illiquidity, and potentially lower economic growth in markets in Europe, which may adversely affect the value of your investment in the Fund. 

Issuer Risk. An issuer in which the Fund invests may perform poorly, and the value of its securities may therefore decline, which may negatively affect the Fund’s performance. Underperformance of an issuer may be caused by poor management decisions, competitive pressures, breakthroughs in technology, reliance on suppliers, labor problems or shortages, corporate restructurings, fraudulent disclosures, natural disasters, military confrontations and actions, war, terrorism, disease/virus outbreaks and epidemics or other events, conditions and factors. 

Foreign Currency Risk. The performance of the Fund may be materially affected positively or negatively by foreign currency strength or weakness relative to the U.S. dollar, particularly if the Fund invests a significant percentage of its assets in foreign securities or other assets denominated in currencies other than the U.S. dollar. 

Growth Securities Risk. Growth securities typically trade at a higher multiple of earnings than other types of equity securities. Accordingly, the market values of growth securities may never reach their expected market value and may decline in price. In addition, growth securities, at times, may not perform as well as value securities or the stock market in general, and may be out of favor with investors for varying periods of time. 

Performance Information

The following bar chart and table show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. The bar chart shows how the Fund’s Class Inst share performance has varied for each full calendar year shown. The table below the bar chart compares the Fund’s returns for the periods shown with those of the MSCI ACWI ex USA Growth Index (Net), the Fund's primary benchmark, and those of the MSCI ACWI ex USA Index (Net), the Fund's secondary benchmark. The MSCI ACWI ex USA Growth Index (Net) captures large- and mid-cap securities exhibiting overall growth style characteristics across 22 developed market countries and 24 emerging market countries. The MSCI ACWI ex USA Index (Net) captures large- and mid-cap representation across 22 of 23 developed market countries (excluding the United States) and 24 emerging market countries. As of March 31, 2022, the MSCI ACWI ex USA Index (Net) had 2,312 constituents and covered approximately 85% of the global equity opportunity set outside the United States. 

The performance of one or more share classes shown in the Average Annual Total Returns table below includes the Fund’s Class Inst share returns (adjusted to reflect the higher class-related operating expenses of such classes, where applicable) for periods prior to the indicated inception date of such share classes. Except for differences in fees and expenses, all share classes of the Fund would have substantially similar annual returns because all share classes of the Fund invest in the same portfolio of securities. 

The after-tax returns shown in the Average Annual Total Returns table below are calculated using the highest historical individual U.S. federal marginal income tax rates in effect during the period indicated in the table and do not reflect the impact of state, local or foreign taxes. Your actual after-tax returns will depend on your personal tax situation and may differ from those shown in the table. In addition, the after-tax returns shown in the table do not apply to shares held in tax-advantaged accounts such as 401(k) plans or Individual Retirement Accounts (IRAs). The after-tax returns are shown only for Class Inst shares and will vary for other share classes. 

The Fund’s past performance (before and after taxes) is no guarantee of how the Fund will perform in the future. Updated performance information can be obtained by calling toll-free 800.345.6611 or visiting columbiathreadneedleus.com. 

Prospectus 2022 9

Columbia Acorn International Select^SM

Summary of the Fund (continued)

Year by Year Total Return (%) as of December 31 Each Year*	Best and Worst Quarterly Returns During the Period Shown in the Bar Chart
	Best	2nd Quarter 2020	26.16%
	Worst	1st Quarter 2020	-25.62%

* Year to Date return as of March 31, 2022: -18.63%

 Average Annual Total Returns After Applicable Sales Charges (for periods ended December 31, 2021)

	Share Class Inception Date	1 Year	5 Years	10 Years
Class Inst	11/23/1998
returns before taxes		10.79%	15.88%	10.61%
returns after taxes on distributions		9.52%	14.75%	9.15%
returns after taxes on distributions and sale of Fund shares		7.34%	12.65%	8.33%
Class A returns before taxes	10/16/2000	4.15%	14.23%	9.66%
Class Adv returns before taxes	11/08/2012	10.78%	15.89%	10.60%
Class C returns before taxes	10/16/2000	8.68%	14.73%	9.47%
Class Inst2 returns before taxes	11/08/2012	10.87%	15.98%	10.67%
Class Inst3 returns before taxes	11/08/2012	10.93%	16.04%	10.72%
MSCI ACWI ex USA Growth Index (Net) (reflects reinvested dividends net of withholding taxes but reflects no deductions for fees, expenses or other taxes)		5.09%	13.06%	9.13%
MSCI ACWI ex USA Index (Net) (reflects reinvested dividends net of withholding taxes but reflects no deductions for fees, expenses or other taxes)		7.82%	9.61%	7.28%

Fund Management

Investment Manager: Columbia Wanger Asset Management, LLC

Portfolio Management	Title	Role with Fund	Service with the Fund Since
Stephen Kusmierczak, CFA	International Team Head, Portfolio Manager and Analyst	Lead Portfolio Manager or Co-Portfolio Manager since 2016	2001
Hans F. Stege	Portfolio Manager and Analyst	Co-Portfolio Manager since 2019	2017

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Columbia Acorn International Select^SM

Summary of the Fund (continued)

Purchase and Sale of Fund Shares

You may purchase or redeem shares of the Fund on any business day by contacting the Fund in the ways described below:

Online	Regular Mail	Express Mail	By Telephone
columbiathreadneedleus.com/investor/	Columbia Management Investment Services Corp. P.O. Box 219104 Kansas City, MO 64121-9104	Columbia Management Investment Services Corp. c/o DST Asset Manager Solutions, Inc. 430 W 7th Street, Suite 219104 Kansas City, MO 64105-1407	800.422.3737

You may purchase shares and receive redemption proceeds by electronic funds transfer, by check or by wire. If you maintain your account with a broker-dealer or other financial intermediary, you must contact that financial intermediary to buy, sell or exchange shares of the Fund through your account with the intermediary.

The minimum initial investment amounts for the share classes offered by the Fund are shown below:

Minimum Initial Investment

Class	Category of eligible account	For accounts other than Systematic Investment Plan accounts (as described in the Fund’s Prospectus)	For Systematic Investment Plan accounts
Classes A & C	All accounts other than IRAs	$2,000	$100
	IRAs	$1,000	$100
Classes Adv & Inst	All eligible accounts	$0, $1,000 or $2,000 depending upon the category of eligible investor	$100
Class Inst2	All eligible accounts	None	N/A
Class Inst3	All eligible accounts	$0, $1,000, $2,000 or $1 million depending upon the category of eligible investor	$100 (for certain eligible investors)

More information about these minimums can be found in the Buying, Selling and Exchanging Shares - Buying Shares section of the prospectus. There is no minimum additional investment for any share class.

Tax Information

The Fund normally distributes net investment income and net realized capital gains, if any, to shareholders. These distributions are generally taxable to you as ordinary income, qualified dividend income or capital gains, unless you are investing through a tax-advantaged account, such as a 401(k) plan or an IRA. If you are investing through a tax-advantaged account, you may be taxed upon withdrawals from that account.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase the Fund through a broker-dealer or other financial intermediary (such as a bank), the Fund and its related companies – including the Investment Manager, the Distributor and Columbia Management Investment Services Corp. (the Transfer Agent) – may pay the intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your financial advisor to recommend the Fund over another investment. These potential conflicts of interest may be heightened with respect to broker-dealers owned by Ameriprise Financial, Inc. (Ameriprise Financial) and/or its affiliates. Ask your financial advisor or visit your financial intermediary's website for more information.

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More Information About the Fund

Investment Objective

Columbia Acorn International Select^SM (the Fund) seeks long-term capital appreciation. The Fund’s investment objective is not a fundamental policy of the Fund and may be changed by the Fund’s Board of Trustees (the Board) without shareholder approval. There is no assurance the Fund’s objective will be achieved.

Principal Investment Strategies

Under normal circumstances, the Fund invests at least 65% of its net assets in foreign companies in developed markets (for example, Japan, Canada and the United Kingdom).

The Fund also may invest up to 35% of its total assets in companies in emerging markets (for example, China, India and Brazil). The Fund generally invests in at least three countries other than the United States but may invest up to 25% of its total assets in securities of U.S. issuers.

Under normal circumstances, the Fund invests a majority of its net assets in the common stock of small- and mid-sized companies with market capitalizations generally in the range of market capitalizations in the MSCI ACWI ex USA Growth Index (Net), the Fund's primary benchmark, (the Index) at the time of purchase (between $912.3 million and $2.3 trillion as of March 31, 2022). The market capitalization range and composition of companies in the Index are subject to change. As such, the size of the companies in which the Fund invests may change. The Fund determines a company’s market capitalization at the time of investment. As long as a majority of its net assets are invested in companies within the Index, the Fund may continue to hold and make new investments in a security even if the company’s market capitalization grows beyond the market capitalization of the largest company within the Index or falls below the market capitalization of the smallest company within the Index.

Columbia Wanger Asset Management, LLC, the Fund's investment adviser (the Investment Manager), believes that stocks of small- and mid-sized companies, which generally are not as well known by financial analysts as larger companies, may offer higher return potential than stocks of larger companies. The Fund also may invest in larger-sized companies. The Investment Manager from time to time emphasizes one or more sectors in selecting the Fund’s investments, including the health care, industrials, and information technology sectors.

The Fund invests in a limited number of foreign companies (generally between 30-60), offering the potential to provide above-average growth over time. In pursuit of the Fund’s objective, the portfolio managers will take advantage of the research and stock-picking capabilities of the Investment Manager and will generally concentrate the Fund’s investments in those sectors, companies, geographic regions or industries that the portfolio managers believe offer the best investment return potential.

The Investment Manager typically seeks companies with:

■ A strong business franchise that offers growth potential.

■ Products and services in which the company has a competitive advantage.

■ A stock price the Investment Manager believes is reasonable relative to the assets and earning power of the company.

The Investment Manager may sell a portfolio holding if the security reaches the Investment Manager's price target, if the company has a deterioration of fundamentals, such as failing to meet key operating benchmarks, or if the Investment Manager believes other securities are more attractive. The Investment Manager also may sell a portfolio holding to fund redemptions.

Principal Risks

An investment in the Fund involves risks, including those described below, among others. There is no assurance that the Fund will achieve its investment objective and you may lose money. The value of the Fund’s holdings may decline, and the Fund’s net asset value (NAV) and share price may go down. An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

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Active Management Risk. The Fund is actively managed and its performance therefore will reflect, in part, the ability of the Investment Manager to select investments and to make investment decisions that will achieve the Fund’s investment objective. The Investment Manager’s active management of the Fund could cause the Fund to underperform its benchmark index and/or other funds with similar investment objectives and/or strategies.

Market Risk. The Fund may incur losses due to declines in the value of one or more securities in which it invests. These declines may be due to factors affecting a particular issuer, or the result of, among other things, political, regulatory, market, economic or social developments affecting the relevant market(s) more generally. In addition, turbulence in financial markets and reduced liquidity in equity, credit and/or fixed income markets may negatively affect many issuers, which could adversely affect the Fund’s ability to price or value hard-to-value assets in thinly traded and closed markets and could cause significant redemptions and operational challenges. Global economies and financial markets are increasingly interconnected, and conditions and events in one country, region or financial market may adversely impact issuers in a different country, region or financial market. These risks may be magnified if certain events or developments adversely interrupt the global supply chain; in these and other circumstances, such risks might affect companies worldwide. As a result, local, regional or global events such as terrorism, war, other conflicts, natural disasters, disease/virus outbreaks and epidemics or other public health issues, recessions, depressions or other events – or the potential for such events – could have a significant negative impact on global economic and market conditions.

The large-scale invasion of Ukraine by Russia in February 2022 has resulted in sanctions and market disruptions including declines in regional and global stock and commodity markets and significant devaluations of Russian currency. The extent and duration of the military action are impossible to predict but could be significant. Market disruption caused by the Russian military action, and any counter measures or responses thereto (including international sanctions, a downgrade in the country’s credit rating, purchasing and financing restrictions, boycotts, tariffs, changes in consumer or purchaser preferences, cyberattacks and espionage) could have severe adverse impacts on regional and/or global securities and commodities markets, including markets for oil and natural gas. These impacts may include reduced market liquidity, distress in credit markets, further disruption of global supply chains, increased risk of inflation, and limited access to investments in certain international markets and/or issuers. These developments and other related events could negatively impact Fund performance.

The pandemic caused by coronavirus disease 2019 and its variants (COVID-19) has resulted in, and may continue to result in, significant global economic and societal disruption and market volatility due to disruptions in market access, resource availability, facilities operations, imposition of tariffs, export controls and supply chain disruption, among others. Such disruptions may be caused, or exacerbated by, quarantines and travel restrictions, workforce displacement and loss in human and other resources. The uncertainty surrounding the magnitude, duration, reach, costs and effects of the global pandemic, as well as actions that have been or could be taken by governmental authorities or other third parties, present unknowns that are yet to unfold. The impacts, as well as the uncertainty over impacts to come, of COVID-19 – and any other infectious illness outbreaks, epidemics and pandemics that may arise in the future – could negatively affect global economies and markets in ways that cannot necessarily be foreseen. In addition, the impact of infectious illness outbreaks and epidemics in less developed countries may be greater due to generally less established healthcare systems, governments and financial markets. Public health crises caused by the COVID-19 outbreak may exacerbate other pre-existing political, social and economic risks in certain countries or globally. The disruptions caused by COVID-19 could prevent the Fund from executing advantageous investment decisions in a timely manner and negatively impact the Fund’s ability to achieve its investment objective. Any such events could have a significant adverse impact on the value and risk profile of the Fund.

Sector Risk. At times, the Fund may have a significant portion of its assets invested in securities of companies conducting business within one or more economic sectors, including the health care, industrials, and information technology sectors. Companies in the same sector may be similarly affected by economic, regulatory, political or market events or conditions, which may make the Fund more vulnerable to unfavorable developments in that sector than funds that invest more broadly. Generally, the more broadly the Fund invests, the more it spreads risk and potentially reduces the risks of loss and volatility.

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■ Health Care Sector. The Fund is more susceptible to the particular risks that may affect companies in the health care sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the health care sector are subject to certain risks, including restrictions on government reimbursement for medical expenses, government approval of medical products and services, competitive pricing pressures, and the rising cost of medical products and services (especially for companies dependent upon a relatively limited number of products or services), among others. Performance of such companies may be affected by factors including, government regulation, obtaining and protecting patents (or the failure to do so), product liability and other similar litigation as well as product obsolescence.

■ Industrials Sector. The Fund is more susceptible to the particular risks that may affect companies in the industrials sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the industrials sector are subject to certain risks, including changes in supply and demand for their specific product or service and for industrial sector products in general, including decline in demand for such products due to rapid technological developments and frequent new product introduction. Performance of such companies may be affected by factors including government regulation, world events, economic conditions and risks for environmental damage and product liability claims.

■ Information Technology Sector. The Fund is more susceptible to the particular risks that may affect companies in the information technology sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the information technology sector are subject to certain risks, including the risk that new services, equipment or technologies will not be accepted by consumers and businesses or will become rapidly obsolete. Performance of such companies may be affected by factors including obtaining and protecting patents (or the failure to do so) and significant competitive pressures, including aggressive pricing of their products or services, new market entrants, competition for market share and short product cycles due to an accelerated rate of technological developments. Such competitive pressures may lead to limited earnings and/or falling profit margins. As a result, the value of their securities may fall or fail to rise. In addition, many information technology sector companies have limited operating histories and prices of these companies’ securities historically have been more volatile than other securities, especially over the short term. Some companies in the information technology sector are facing increased government and regulatory scrutiny and may be subject to adverse government or regulatory action, which could negatively impact the value of their securities.

Select Portfolio Risk. Because the Fund may invest in a limited number of companies, the Fund as a whole is subject to greater risk of loss if any of its portfolio securities decline in price. The Fund accordingly may be more susceptible to economic, political and regulatory developments than a fund that invests in a greater number of companies. In addition, the Fund’s holdings and weightings will diverge significantly from its primary benchmark’s holdings and weightings and the Fund may therefore experience greater risk and volatility relative to the benchmark. Because the Fund may invest in more than one company concentrated in a similar industry, sector or geographic region, the Fund may be even more concentrated than the number of companies it may hold would suggest.

Liquidity and Trading Volume Risk. Due to market conditions, including uncertainty regarding the price of a security, it may be difficult for the Fund to buy or sell portfolio securities at a desirable time or price, which could result in investment losses. This risk of portfolio illiquidity is heightened with respect to small- and mid-cap securities, generally, and foreign small- and mid-cap securities in particular. The Fund may have to lower the selling price, liquidate other investments, or forego another, more appealing investment opportunity as a result of illiquidity in the markets. The Investment Manager will fair value in good faith any securities it deems to be illiquid under consistently applied procedures established by the Fund’s Board. Market conditions are always changing and vary by country and industry sector, and investing in international markets involves unique risks. Although it is difficult to accurately assess trends in trading volumes in foreign markets, a reduction in trading volumes poses challenges to the Fund. This is particularly so because the Fund focuses on small- and mid-cap companies that usually have lower trading volumes and often takes sizeable positions in portfolio companies. As a result of lower trading volumes, it may take longer to buy or sell securities, which can exacerbate the Fund’s exposure to volatile markets. The Fund may also be limited in its ability to execute favorable trades in portfolio securities in response to changes in share prices and fundamentals. If the Fund is forced to sell securities to meet redemption requests or other cash needs, or in the

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More Information About the Fund (continued)

case of an event affecting liquidity in a particular market or markets, it may be forced to dispose of those securities under disadvantageous circumstances and at a loss. As the Fund grows in size or, conversely, if it faces significant redemption pressure, these considerations take on increasing significance and may adversely impact performance.

Foreign Securities Risk. Investments in or exposure to securities of foreign companies may involve heightened risks relative to investments in or exposure to securities of U.S. companies. For example, foreign markets can be extremely volatile. Foreign securities may also be less liquid, making them more difficult to trade, than securities of U.S. companies so that the Fund may, at times, be unable to sell foreign securities at desirable times or prices. Brokerage commissions, custodial costs and other fees are also generally higher for foreign securities. The Fund may have limited or no legal recourse in the event of default with respect to certain foreign securities, including those issued by foreign governments. In addition, foreign governments may impose withholding or other taxes on the Fund’s income, capital gains or proceeds from the disposition of foreign securities, which could reduce the Fund’s return on such securities. In some cases, such withholding or other taxes could potentially be confiscatory. Other risks include: possible delays in the settlement of transactions or in the payment of income; generally less publicly available information about foreign companies; the impact of economic, political, social, diplomatic or other conditions or events (including, for example, military confrontations and actions, war, other conflicts, terrorism and disease/virus outbreaks and epidemics), possible seizure, expropriation or nationalization of a company or its assets or the assets of a particular investor or category of investors; accounting, auditing and financial reporting standards that may be less comprehensive and stringent than those applicable to domestic companies; the imposition of economic and other sanctions against a particular foreign country, its nationals or industries or businesses within the country; and the generally less stringent standard of care to which local agents may be held in the local markets. In addition, it may be difficult to obtain reliable information about the securities and business operations of certain foreign issuers. Governments or trade groups may compel local agents to hold securities in designated depositories that are not subject to independent evaluation. The less developed a country’s securities market is, the greater the level of risks. Economic sanctions may be, and have been, imposed against certain countries, organizations, companies, entities and/or individuals. Economic sanctions and other similar governmental actions could, among other things, effectively restrict or eliminate the Fund’s ability to purchase or sell securities, and thus may make the Fund’s investments in such securities less liquid or more difficult to value. In addition, as a result of economic sanctions, the Fund may be forced to sell or otherwise dispose of investments at inopportune times or prices, which could result in losses to the Fund and increased transaction costs. These conditions may be in place for a substantial period of time and enacted with limited advance notice to the Fund. The risks posed by sanctions against a particular foreign country, its nationals or industries or businesses within the country may be heightened to the extent the Fund invests significantly in the affected country or region or in issuers from the affected country that depend on global markets. Additionally, investments in certain countries may subject the Fund to a number of tax rules, the application of which may be uncertain. Countries may amend or revise their existing tax laws, regulations and/or procedures in the future, possibly with retroactive effect. Changes in or uncertainties regarding the laws, regulations or procedures of a country could reduce the after-tax profits of the Fund, directly or indirectly, including by reducing the after-tax profits of companies located in such countries in which the Fund invests, or result in unexpected tax liabilities for the Fund.

Operational and Settlement Risks of Foreign Securities. The Fund’s foreign securities are generally held outside the United States in the primary market for the securities in the custody of certain eligible foreign banks and trust companies (“foreign sub-custodians”), as permitted under the Investment Company Act of 1940 (the 1940 Act). Settlement practices for foreign securities may differ from those in the United States. Some countries have limited governmental oversight and regulation of industry practices, stock exchanges, depositories, registrars, brokers and listed companies, which increases the risk of corruption and fraud and the possibility of losses to the Fund. In particular, under certain circumstances, foreign securities may settle on a delayed delivery basis, meaning that the Fund may be required to make payment for securities before the Fund has actually received delivery of the securities or deliver securities prior to the receipt of payment. Typically, in these cases, the Fund will receive evidence of ownership in accordance with the generally accepted settlement practices in the local market entitling the Fund to delivery or payment at a future date, but there is a risk that the security will not be delivered to the Fund or that payment will not be received, although the Fund and its foreign sub-custodians take reasonable precautions to mitigate this risk. Losses can also result from lost, stolen or counterfeit securities; defaults by brokers and banks; failures or defects of the settlement system; or poor and improper record keeping by registrars and issuers.

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More Information About the Fund (continued)

Share Blocking. Share blocking refers to a practice in certain foreign markets under which an issuer’s securities are blocked from trading at the custodian or sub-custodian level for a specified number of days before and, in certain instances, after a shareholder meeting where a vote of shareholders takes place. The blocking period can last up to several weeks. Share blocking may prevent the Fund from buying or selling securities during this period, because during the time shares are blocked, trades in such securities will not settle. It may be difficult or impossible to lift blocking restrictions, with the particular requirements varying widely by country. As a consequence of these restrictions, the Investment Manager, on behalf of the Fund, may abstain from voting proxies in markets that require share blocking.

Emerging Market Securities Risk. Securities issued by foreign governments or companies in emerging market countries, such as China, Russia and certain countries in Eastern Europe, the Middle East, Asia, Latin America or Africa, are more likely to have greater exposure to the risks of investing in foreign securities that are described in Foreign Securities Risk. In addition, emerging market countries are more likely to experience instability resulting, for example, from rapid changes or developments in social, political, economic or other conditions. Their economies are usually less mature and their securities markets are typically less developed with more limited trading activity (i.e., lower trading volumes and less liquidity) than more developed countries. Emerging market securities tend to be more volatile, and may be more susceptible to market manipulation, than securities in more developed markets. Many emerging market countries are heavily dependent on international trade and have fewer trading partners, which makes them more sensitive to world commodity prices and economic downturns in other countries. Some emerging market countries have a higher risk of currency devaluations, and some of these countries may experience periods of high inflation or rapid changes in inflation rates and may have hostile relations with other countries. Due to the differences in the nature and quality of financial information of issuers of emerging market securities, including auditing and financial reporting standards, financial information and disclosures about such issuers may be unavailable or, if made available, may be considerably less reliable than publicly available information about other foreign securities.

Operational and Settlement Risks of Securities in Emerging Markets. In addition to having less developed securities markets, banks in emerging markets that are eligible foreign sub-custodians may be recently organized, lack extensive operating experience or lack effective government oversight or regulation. In addition, there may be legal restrictions or limitations on the ability of the Fund to recover assets held in custody by a foreign sub-custodian in the event of the bankruptcy of the sub-custodian. Because settlement systems may be less organized than in developed markets and because delivery versus payment settlement may not be possible or reliable, there may be a greater risk that settlement may be delayed and that cash or securities of the Fund may be lost because of failures of or defects in the system, including fraud or corruption. Settlement systems in emerging markets also have a higher risk of failed trades.

Risks Related to Currencies and Corporate Actions in Emerging Markets. Risks related to currencies and corporate actions are also greater in emerging market countries than in developed countries. For example, some emerging market countries may have fixed or managed currencies that are not free-floating against the U.S. dollar. Further, certain currencies may not have an active trading market internationally, or countries may have varying exchange rates. Some emerging market countries have a higher risk of currency devaluations, and some of these countries may experience sustained periods of high inflation or rapid changes in inflation rates which can have negative effects on a country’s economy and securities markets. Corporate action procedures in emerging market countries may be less reliable and have limited or no involvement by the depositories and central banks. Lack of standard practices and payment systems can lead to significant delays in payment.

Risks Related to Corporate and Securities Laws in Emerging Markets. Securities laws in emerging markets may be relatively new and unsettled and, consequently, there is a risk of rapid and unpredictable change in laws regarding foreign investment, securities regulation, title to securities and shareholder rights. Accordingly, foreign investors may be adversely affected by new or amended laws and regulations. In addition, the systems of corporate governance to which issuers in certain emerging markets are subject may be less advanced than the systems to which issuers located in more developed countries are subject, and therefore, shareholders of such issuers may not receive many of the protections available to shareholders of issuers located in more developed countries. These risks may be heightened in China and Russia.

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Small- and Mid-Cap Company Securities Risk. Securities of small- and mid-cap companies can, in certain circumstances, have a higher potential for gains than securities of larger, more established companies but may also have more risk. For example, small- and mid-cap companies may be more vulnerable to market downturns and adverse business or economic events than larger companies because they may have more limited financial resources and business operations. Small- and mid-cap companies are also more likely than larger companies to have more limited product lines and operating histories and to depend on smaller and generally less experienced management teams. Securities of small- and mid-cap companies may trade less frequently and in smaller volumes and may be less liquid and fluctuate more sharply in value than securities of larger companies. When the Fund takes significant positions in small- and mid-cap companies with limited trading volumes, the liquidation of those positions, particularly in a distressed market, could be prolonged and result in Fund investment losses that would affect the value of your investment in the Fund. In addition, some small- and mid-cap companies may not be widely followed by the investment community, which can lower the demand for their stocks.

Large-Cap Company Securities Risk. Larger, more established companies may be unable to respond quickly to new competitive challenges, such as changes in consumer tastes or innovative smaller competitors. Also, large-cap companies are sometimes unable to attain the high growth rates of successful, smaller companies, especially during extended periods of economic expansion.

Geographic Focus Risk. The Fund may be particularly susceptible to risks related to economic, political, regulatory or other events or conditions affecting issuers and countries within the specific geographic regions in which the Fund invests. Currency devaluations could occur in countries that have not yet experienced currency devaluation to date, or could continue to occur in countries that have already experienced such devaluations. As a result, the Fund’s NAV may be more volatile than the NAV of a more geographically diversified fund.

■ Asia Pacific Region. A number of countries in the Asia Pacific region are considered underdeveloped or developing, including from a political, economic and/or social perspective, and may have relatively unstable governments and economies based on limited business, industries and/or natural resources or commodities. Events in any one country within the region may impact that country, other countries in the region or the region as a whole. As a result, events in the region will generally have a greater effect on the Fund than if the Fund were more geographically diversified in a region with more developed countries and economies. This could result in increased volatility in the value of the Fund’s investments and losses for the Fund. Continued growth of economies and securities markets in the region will require sustained economic and fiscal discipline, as well as continued commitment to governmental and regulatory reforms. Development also may be influenced by international economic conditions, including those in the United States and Japan, and by world demand for goods or natural resources produced in countries in the Asia Pacific region. Securities markets in the region are generally smaller and have a lower trading volume than those in the United States, which may result in the securities of some companies in the region being less liquid than U.S. or other foreign securities. Some currencies, inflation rates or interest rates in the Asia Pacific region are or can be volatile, and some countries in the region may restrict the flow of money in and out of the country. The risks described under “Emerging Market Securities Risk” and  “Foreign Securities Risk” may be more pronounced due to the Fund’s focus on investments in the region.

■ Europe. The Fund is particularly susceptible to risks related to economic, political, regulatory or other events or conditions, including acts of war or other conflicts in the region, affecting issuers and countries in Europe. Countries in Europe are often closely connected and interdependent, and events in one European country can have an adverse impact on, and potentially spread to, other European countries. Most developed countries in Western Europe are members of the EU, and many are also members of the European Economic and Monetary Union (EMU). European countries can be significantly affected by the tight fiscal and monetary controls that the EMU imposes on its members and with which candidates for EMU membership are required to comply. In addition, significant private and public sectors’ debt problems of a single EU country can pose economic risks to the EU as a whole. Unemployment in Europe has historically been higher than in the United States and public deficits are an ongoing concern in many European countries. As a result, the Fund’s NAV may be more volatile than the NAV of a more geographically diversified fund. If securities of issuers in Europe fall out of favor, it may cause the Fund to underperform other funds that do not focus their investments in this region of the world. The UK’s departure from the EU single market became effective January 1, 2021 with the end of the Brexit transition period and the

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More Information About the Fund (continued)

post‐Brexit trade deal between the UK and EU taking effect on December 31, 2020. The impact of any partial or complete dissolution of the EU on the UK and European economies and the broader global economy could be significant, resulting in negative impacts on currency and financial markets generally, such as increased volatility and illiquidity, and potentially lower economic growth in markets in the UK, Europe and globally, which may adversely affect the value of your investment in the Fund. The impact of Brexit in the near‐ and long‐term is still unknown and could have additional adverse effects on economies, financial markets, currencies and asset valuations around the world. Any attempt by the Fund to hedge against or otherwise protect its portfolio or to profit from such circumstances may fail and, accordingly, an investment in the Fund could lose money over short or long periods. For more information on the risks associated with Brexit, see the Statement of Additional Information.

Issuer Risk. An issuer in which the Fund invests may perform poorly, and the value of its securities may therefore decline, which may negatively affect the Fund’s performance. Underperformance of an issuer may be caused by poor management decisions, competitive pressures, breakthroughs in technology, reliance on suppliers, labor problems or shortages, corporate restructurings, fraudulent disclosures, natural disasters, military confrontations and actions, war, terrorism, disease/virus outbreaks and epidemics or other events, conditions and factors.

Foreign Currency Risk. The performance of the Fund may be materially affected positively or negatively by foreign currency strength or weakness relative to the U.S. dollar, particularly if the Fund invests a significant percentage of its assets in foreign securities or other assets denominated in currencies other than the U.S. dollar. Currency rates in foreign countries may fluctuate significantly over short or long periods of time for a number of reasons, including changes in interest rates, imposition of currency controls and economic or political developments in the U.S. or abroad. The Fund may also incur currency conversion costs when converting foreign currencies into U.S. dollars and vice versa. Restrictions on currency trading may be imposed by foreign countries, which may adversely affect the value of your investment in the Fund. Even though the currencies of some countries may be pegged to the U.S. dollar, the conversion rate may be controlled by government regulation or intervention at levels significantly different than what would normally prevail in a free market. Significant revaluations of the U.S. dollar exchange rate of these currencies could cause substantial reductions in the Fund’s NAV.

Growth Securities Risk. Growth securities typically trade at a higher multiple of earnings than other types of equity securities. Accordingly, the market values of growth securities may never reach their expected market value and may decline in price. In addition, growth securities, at times, may not perform as well as value securities or the stock market in general, and may be out of favor with investors for varying periods of time.

Additional Investment Strategies and Policies

This section describes certain investment strategies and policies that the Fund may utilize in pursuit of its investment objective and some additional factors and risks involved with investing in the Fund. For information about risks associated with changing levels of Fund distributions, see the SAI.

Changing the Fund’s Investment Objective and Policies

The Fund’s investment objective and non-fundamental investment policies (including its principal and additional investment strategies) can be changed by the Board without shareholder approval, but may require notice to shareholders in certain instances. The Fund’s fundamental investment policies, as identified in the Fund’s Statement of Additional Information (SAI), may be changed only with Board and shareholder approval in accordance with the voting requirements of the 1940 Act. For additional information about changing the Fund’s fundamental and non-fundamental investment policies, see the SAI.

Investment Guidelines

As a general matter, and except as specifically described in the discussion of the Fund's principal investment strategies in this prospectus, whenever an investment policy or limitation states a percentage of the Fund's assets that may be invested in any security or other asset or sets forth a policy regarding an investment standard, compliance with that percentage limitation or standard will be determined based on the characteristics of a company at the time of initial purchase, and subsequent changes in a characteristic are not taken into account.

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Holding Other Kinds of Investments

The Fund may hold other investments that are not part of its principal investment strategies. These investments and their risks are described below and/or in the SAI. The Fund may choose not to invest in certain securities described in this prospectus and in the SAI, although it has the ability to do so. Information on the Fund’s holdings can be found in the Fund’s shareholder reports or by visiting columbiathreadneedleus.com.

Transactions in Derivatives

The Fund may enter into derivative transactions or otherwise have exposure to derivative transactions through underlying investments. The Fund expects to enter into such transactions primarily in the form of stock index futures in order to obtain exposure to the overall sector of the market represented by a particular stock index or to invest the Fund’s uninvested cash balances in a manner that the Investment Manager believes aligns more closely with the Fund’s investment strategy than simply holding short-term fixed income investments or cash equivalents (known as cash equitization). Derivatives are financial contracts whose values are, for example, based on (or “derived” from) traditional securities (such as a stock or bond), assets (such as a commodity like gold or a foreign currency), reference rates (such as the Secured Overnight Financing Rate (commonly known as SOFR) or the London Interbank Offered Rate (commonly known as LIBOR)) or market indices (such as the Standard & Poor's (S&P) 500^® Index). The use of derivatives is a highly specialized activity which involves investment techniques and risks different from those associated with ordinary portfolio securities transactions. Derivatives involve special risks and may result in losses or may limit the Fund's potential gain from favorable market movements. Derivative strategies typically expose the Fund to gains and losses in excess of the amount actually invested in the derivative. This characteristic of a derivative (known as "leverage") may exaggerate a loss, potentially causing the Fund to lose more money than it would have lost had it invested in the underlying security or other asset directly. The values of derivatives may move in unexpected ways, especially in unusual (including distressed) market conditions, and may result in increased volatility in the value of the derivative and/or the Fund’s shares, among other consequences. The use of derivatives may also increase the amount of taxes payable by shareholders holding shares in a taxable account. Other risks arise from the Fund's potential inability to terminate or to sell derivative positions. A liquid secondary market may not always exist for the Fund's derivative positions at times when the Fund might wish to terminate or to sell such positions. Over-the-counter instruments (investments not traded on an exchange) may be illiquid, and transactions in derivatives traded in the over-the-counter market are subject to the risk that the other party will not meet its obligations. The use of derivatives also involves the risks of mispricing or improper valuation and that changes in the value of the derivative may not correlate perfectly with the underlying security, asset, reference rate or index. The Fund also may not be able to find a suitable derivative transaction counterparty, and thus may be unable to engage in derivative transactions when it is deemed favorable to do so, or at all. U.S. federal legislation has been enacted that provides for new clearing, margin, reporting and registration requirements for participants in the derivatives market. These changes could restrict and/or impose significant costs or other burdens upon the Fund’s participation in derivatives transactions. The U.S. government and the European Union (and some other jurisdictions) have enacted regulations and similar requirements that prescribe clearing, margin, reporting and registration requirements for participants in the derivatives market. These requirements are evolving and their ultimate impact on the Fund remains unclear but such impact could include restricting and/or imposing significant costs or other burdens upon the Fund’s participation in derivatives transactions. Additionally, in October 2020, the SEC adopted new regulations governing the use of derivatives by registered investment companies. Once effective, Rule 18f-4 will, among other things, require funds that invest in derivative instruments beyond a specified limited amount to apply a value-at-risk based limit to their use of certain derivative instruments and establish a comprehensive derivatives risk management program. A fund that uses derivative instruments in a limited amount will not be subject to the full requirements of Rule 18f-4. Compliance with Rule 18f-4 will not be required until August 2022. Rule 18f-4 could have an adverse impact on the Fund’s performance and ability to implement its investment strategies as it has historically. For more information on the risks of derivative investments and strategies, see the SAI.

LIBOR Phase-Out Risk. Many derivatives and other financial instruments utilize or are permitted to utilize a floating interest rate based on LIBOR. On July 27, 2017, the United Kingdom's Financial Conduct Authority (FCA) announced its intention to phase out the use of LIBOR by the end of 2021. The FCA and the ICE Benchmark Administration have since announced that a majority of U.S. dollar LIBOR settings will cease publication after June 30, 2023. A subset of

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non-U.S. dollar LIBOR settings are continuing to be published on a “synthetic” basis and it is possible that a subset of U.S. dollar LIBOR settings will also be published after June 30, 2023 on a “synthetic” basis. Any such publications are, or would be considered, non-representative of the underlying market. Uncertainty related to the liquidity impact of changes in reference rates, and how to appropriately adjust these rates at the time of transition, poses risks for the Fund. It is difficult to predict the full impact of the transition away from LIBOR on the Fund until new reference rates and fallbacks for both legacy and new products, instruments and contracts are commercially accepted and market practices become more settled. The Investment Manager monitors the Fund's LIBOR exposure risks, including the extent to which any derivative and/or debt investments allow for the utilization of alternative rate(s), such as the Secured Overnight Financing Rate (SOFR), which the U.S. Federal Reserve is promoting as the alternative reference rate to LIBOR.

Affiliated Fund Investing

The Investment Manager and its affiliate, Columbia Management Investment Advisers, LLC (Columbia Management), each serves as investment adviser to mutual funds and ETFs using the Columbia brand (Columbia Funds), including mutual funds that are structured as “fund-of-funds”, and provides asset-allocation services to (i) shareholders by investing in shares of other Columbia Funds, which may include the Fund (collectively referred to in this section as Underlying Funds), and (ii) discretionary managed accounts (collectively referred to as affiliated products) that invest exclusively in Underlying Funds. These affiliated products, individually or collectively, may own a significant percentage of the outstanding shares of one or more Underlying Funds, and the Investment Manager and Columbia Management seek to balance potential conflicts of interest between the affiliated products and the Underlying Funds in which they invest. The affiliated products’ investment in the Underlying Funds may have the effect of creating economies of scale, possibly resulting in lower expense ratios for the Underlying Funds, because the affiliated products may own substantial portions of the shares of Underlying Funds. However, redemption of Underlying Fund shares by one or more affiliated products could cause the expense ratio of the Underlying Fund to increase, as its fixed costs would be spread over a smaller asset base. Because of large positions of certain affiliated products, the Underlying Funds may experience relatively large inflows and outflows of cash due to affiliated products’ purchases and sales of Underlying Fund shares. Although the Investment Manager or Columbia Management may seek to minimize the impact of these transactions where possible, for example, by structuring them over a reasonable period of time or through other measures, Underlying Funds may experience increased expenses as they buy and sell portfolio securities to manage the cash flow effect related to these transactions. Further, when the Investment Manager or Columbia Management structures transactions over a reasonable period of time in order to manage the potential impact of the buy and sell decisions for the affiliated products, those affiliated products, including funds-of-funds, may pay more or less (for purchase activity), or receive more or less (for redemption activity), for shares of the Underlying Funds than if the transactions were executed in one transaction. In addition, substantial redemptions by affiliated products within a short period of time could require the Underlying Fund to liquidate positions more rapidly than would otherwise be desirable, which may have the effect of reducing or eliminating potential gain or causing it to realize a loss. In order to meet such redemptions, the Underlying Fund may be forced to sell its liquid (or more liquid) positions, leaving the Underlying Fund holding, post-redemption, a relatively larger position in illiquid investments (i.e., any investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without the sale or disposition significantly changing the market value of the investment) or less liquid securities. Substantial redemptions may also adversely affect the ability of the Underlying Fund to implement its investment strategy. The Investment Manager or Columbia Management also has a conflict of interest in determining the allocation of affiliated products’ assets among the Underlying Funds, as it earns different fees from the various Underlying Funds.

Investing in Money Market Funds

The Fund may invest cash, including cash collateral received in connection with its securities lending program, in shares of money market funds, including funds advised by affiliates of the Investment Manager. These funds are not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency. The Fund and its shareholders indirectly bear a portion of the expenses of any money market fund or other fund in which the Fund may invest.

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Lending of Portfolio Securities

The Fund may lend portfolio securities to broker-dealers or other financial intermediaries on a fully collateralized basis in order to earn additional income. The Fund may lose money from securities lending if, for example, the borrower does not return a loaned security and the proceeds from sale of the collateral are not sufficient to replace the borrowed security. The Fund invests collateral in a government money market fund.

Investing Defensively

The Fund may from time to time take temporary defensive investment positions that are inconsistent with the Fund’s principal investment strategies in attempting to respond to adverse market, economic, political, social or other conditions. These investment positions may include, without limitation, investing some or all of its assets in money market instruments or shares of affiliated or unaffiliated money market funds or holding some or all of its assets in cash or cash equivalents. The Fund may take such defensive positions for as long a period as the Investment Manager deems necessary. During these times, the Investment Manager may make frequent portfolio changes, which could result in increased trading expenses and taxes, and decreased Fund performance.

Portfolio Holdings Disclosure

A description of the Fund’s policies and procedures with respect to the disclosure of Fund portfolio securities is available in the SAI. The Fund discloses its portfolio holdings on the Columbia Funds’ website, columbiathreadneedleus.com, as described below. Once posted, the portfolio holdings information will remain available on the website until at least the date on which such Fund files a Form N-CSR or publicly available Form N-PORT (forms filed with the SEC that include portfolio holdings information) for the period that includes the date as of which the information is current.

The Fund considers changes in its portfolio holdings to be confidential information. Consequently, Fund policy generally permits the disclosure of portfolio holdings information only after a certain amount of time has passed. The Fund’s complete portfolio holdings are disclosed approximately 30 to 40 days after each month-end. The top 15 holdings may be available sooner, approximately 15 calendar days after each month-end. Purchases and sales of portfolio securities can take place at any time, so the portfolio holdings information available on the website may not always be current.

Cybersecurity

The Fund, like all companies, may be susceptible to operational and information security risks, including the risk of cyber attacks or failures. As a result, the Fund or its service providers, or the issuers of securities in which the Fund invests, may experience disruptions in business operations that may potentially result in financial losses, the inability of the Fund or Fund shareholders to transact business, violations of applicable privacy and other laws, regulatory fines, penalties, reputational damage, reimbursement or other compensation costs, and/or additional compliance costs. The Fund and its shareholders could be negatively impacted as a result. See the discussion of Cybersecurity Breaches and Technology and Related Systems Failure Risk in the SAI for further information.

Use of Benchmarks

Benchmarks are indices that provide some comparative guidance in assessing the Fund’s performance. The Investment Manager selects the benchmarks it believes provide meaningful comparisons for each Fund. However, there may be different or additional indices that more closely reflect the market sectors in which the Fund invests. The Fund’s benchmarks may change from time to time. The benchmarks included in this prospectus are intended only as guideposts for your assessment of the Fund’s performance.

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 FUNDamentals

Portfolio Holdings Versus the Benchmarks

The Fund does not limit its investments to the securities within its benchmarks, and accordingly the Fund's holdings may diverge significantly from those of the benchmarks selected by the Investment Manager. In addition, the Fund may invest in securities outside the industry and geographic sectors represented in its benchmarks. The Fund's weightings in individual securities, and in industry and geographic sectors, may also vary considerably from those of its benchmarks.

eDelivery and Mailings to Households

In order to reduce shareholder expenses, the Fund may mail only one copy of the Fund’s prospectus and each annual and semiannual report to those addresses shared by two or more accounts. If you wish to receive separate copies of these documents, call 800.345.6611 or, if your shares are held through a financial intermediary, contact your intermediary directly. Additionally, you may elect to enroll in eDelivery to receive electronic versions of these documents, as well as quarterly statements and supplements, by logging into your account at columbiathreadneedleus.com/investor/.

Additional Information on Portfolio Turnover

A mutual fund that replaces, or turns over, more than 100% of its investments in a year may be considered to have a high portfolio turnover rate. A high portfolio turnover rate can generate larger distributions of short-term capital gains to shareholders, which for individuals are generally taxable at higher rates than long-term capital gains for U.S. federal income tax purposes. Also, a high portfolio turnover rate can mean higher brokerage commissions and other transaction costs, which could reduce a fund’s returns. In general, the greater the volume of buying and selling by a fund, the greater the impact that brokerage commissions and other transaction costs will have on its returns. The Fund may sell securities regardless of how long they’ve been held. See the Financial Highlights section of this prospectus for the Fund's portfolio turnover rates for the past five years.

Cash Flows

The timing and magnitude of cash inflows from investors buying Fund shares could prevent the Fund from always being fully invested. Conversely, the timing and magnitude of cash outflows to shareholders redeeming Fund shares could require the Fund to sell portfolio securities at less than opportune times or to hold ready reserves of uninvested cash in amounts larger than might otherwise be the case to meet shareholder redemptions. Either situation could adversely impact the Fund’s performance.

Understanding Annual Fund Operating Expenses

The Fund’s annual operating expenses, as presented in the Annual Fund Operating Expenses table in the Fees and Expenses of the Fund section of this prospectus, generally are based on expenses incurred during the Fund’s most recently completed fiscal year, may vary by share class and are expressed as a percentage (expense ratio) of the Fund’s average net assets during that fiscal year. The expense ratios reflect the Fund’s fee arrangements as of the date of this prospectus and, unless indicated otherwise, are based on expenses incurred during the Fund’s most recent fiscal year. The Fund’s assets will fluctuate, but unless indicated otherwise in the Annual Fund Operating Expenses table, no adjustments have been or will be made to the expense ratios to reflect any differences in the Fund’s average net assets between the most recently completed fiscal year and the date of this prospectus or a later date. In general, the Fund’s expense ratios will increase as its net assets decrease, such that the Fund’s actual expense ratios may be higher than the expense ratios presented in the Annual Fund Operating Expenses table if assets fall. Any commitment by the Investment Manager and/or its affiliates to waive fees and/or cap (reimburse) expenses is expected, in part, to limit the impact of any increase in the Fund’s expense ratios that would otherwise result because of a decrease in the Fund’s assets in the current fiscal year. The Fund’s annual operating expenses are comprised of (i) investment management fees, (ii) distribution and/or service fees, and (iii) other expenses.

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Management fees do not vary by class, but distribution and/or service fees and other expenses may vary by class. Please see Fee Waiver/Expense Reimbursement Arrangements below for information about commitments made by the Investment Manager and/or its affiliates during the performance period covered by this prospectus.

 FUNDamentals

Other Expenses

“Other expenses” consist of the fees the Fund pays to its administrator, custodian, transfer agent, auditors, lawyers and trustees, costs relating to compliance and miscellaneous expenses. Generally, these expenses are allocated on a pro rata basis across all share classes. These expenses include certain sub-transfer agency and shareholder servicing fees. Transfer agency fees and certain shareholder servicing fees, however, are class specific. They differ by share class because the shareholder services provided to each share class may be different. Accordingly, the differences in “other expenses” among share classes are primarily the result of the different transfer agency and shareholder servicing fees applicable to each share class. For more information on these fees, see Choosing a Share Class — Financial Intermediary Compensation.

Fee Waiver/Expense Reimbursement Arrangements

Effective July 1, 2016, the Investment Manager has contractually agreed to permanently reduce the investment advisory fee payable to it by the Fund by 0.05% at all net asset levels.

The Investment Manager has contractually agreed to waive fees and reimburse certain expenses of the Fund through April 30, 2023, so that ordinary operating expenses (excluding transaction costs and certain other investment-related expenses, interest and fees on borrowings, and expenses associated with the Fund’s investment in other investment companies, if any) do not exceed the annual rates of:

Columbia Acorn International Select
Class A	1.24%
Class Adv	0.99%
Class C	1.99%
Class Inst	0.99%
Class Inst2	0.89%
Class Inst3	0.84%

This arrangement may only be amended or terminated with approval from the Fund’s Board of Trustees and the Investment Manager.

Effect of Fee Waivers and/or Expense Reimbursements on Past Performance. The Fund’s returns shown in the Performance Information section of this prospectus reflect the effect of fee waivers and/or reimbursements of Fund expenses by the Investment Manager and/or its affiliates that were in place during the performance period shown in the Performance Information section of this prospectus. Without such fee waivers/expense reimbursements, the Fund’s returns might have been lower.

Board of Trustees

The Fund is governed by the Board. More than 75% of the Fund's Trustees are independent (Independent Trustees), meaning that they are not “interested persons” of the Fund, as defined in the 1940 Act. The Independent Trustees bring backgrounds in business and academia to their task of working with the Fund's officers to establish the Fund's policies and oversee its activities. Among the Trustees' responsibilities are: selecting the investment adviser for the Fund; approving the advisory agreement; reviewing other contracts; approving investment policies; monitoring Fund operations, performance, compliance and costs; and nominating or selecting new Trustees.

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Each Trustee serves the Fund for an indefinite term until his or her retirement, resignation, death or removal in accordance with the organizational documents of Columbia Acorn Trust (the Trust). The Trust's Bylaws generally require that Trustees retire at the end of the calendar year in which they attain the age of 75 years. The last meeting to elect Trustees was held on February 27, 2015. Any Trustee may be removed at a shareholders' meeting by a vote representing two-thirds of the net asset value of all shares of the Columbia Acorn family of funds (Columbia Acorn Funds). The mailing address for the Trustees and officers is 71 S. Wacker Drive, Suite 2500, Chicago, Illinois 60606.

For more detailed information about the Board, please refer to the SAI.

Primary Service Provider Contracts

The Fund enters into contractual arrangements (Service Provider Contracts) with various parties, including, among others, the Investment Manager, the Distributor, the Transfer Agent and the Fund’s custodian. The Fund’s Service Provider Contracts are solely among the parties thereto. Shareholders are not parties to, or intended to be third-party beneficiaries of, any Service Provider Contracts. Further, this prospectus, the SAI and any Service Provider Contracts are not intended to give rise to any agreement, duty, special relationship or other obligation between the Fund and any investor, or give rise to any contractual, tort or other rights in any individual shareholder, group of shareholders or other person, including any right to assert a fiduciary or other duty, enforce the Service Provider Contracts against the parties or to seek any remedy thereunder, either directly or on behalf of the Fund. Nothing in the previous sentence should be read to suggest any waiver of any rights under federal or state securities laws.

The Investment Manager, which also serves as the Fund's administrator (the Administrator), Columbia Management, which serves as the Fund's sub-administrator pursuant to an agreement with the Investment Manager (the Sub-Administrator), the Distributor, and the Transfer Agent are all affiliates of Ameriprise Financial. They and their affiliates currently provide key services, including investment advisory, administration, distribution, shareholder servicing and transfer agency services, to the Fund and various other funds, including the Columbia Funds, and are paid for providing these services. These service relationships are described below.

The Investment Manager

Columbia Wanger Asset Management, LLC is located at 71 S. Wacker Drive, Suite 2500, Chicago, Illinois 60606. As of March 31, 2022, the Investment Manager had assets under management of approximately $9.2 billion. The Investment Manager is a registered investment adviser and wholly-owned subsidiary of Columbia Management, which is a wholly-owned subsidiary of Ameriprise Financial. In addition to serving as an investment adviser to mutual funds, the Investment Manager acts as an investment manager for other private funds and institutional accounts.

Subject to oversight by the Board, the Investment Manager manages the day-to-day operations of the Fund, determining what securities and other investments the Fund should buy or sell and executing portfolio transactions. The Investment Manager may use the research and other capabilities of its affiliates and third parties in managing the Fund’s investments.

The Fund pays the Investment Manager a fee for its investment advisory services. The fee is calculated as a percentage of the daily net assets of the Fund and is paid monthly. For the Fund’s most recent fiscal year, aggregate fees paid to the Investment Manager by the Fund amounted to 0.89% of average daily net assets of the Fund, before any applicable reimbursements.

A discussion regarding the basis for the Board’s approval of the renewal of the Fund’s investment management services agreement with the Investment Manager is available in the Fund’s annual report to shareholders for the fiscal year ended December 31, 2021.

The Investment Manager and its investment advisory affiliates, including Columbia Management (Affiliates), around the world may coordinate in providing services to their clients. From time to time, the Investment Manager may engage its Affiliates to provide a variety of services such as investment research, investment monitoring, trading, and discretionary investment management (including portfolio management and proxy voting) to certain accounts managed by the Investment Manager, including the Fund. These Affiliates will provide services to the Fund and other accounts of the Investment Manager either pursuant to delegation agreements, personnel-sharing agreements or similar inter-company or other arrangements or relationships and the Fund will pay no additional fees and expenses

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as a result of any such arrangements or relationships. These Affiliates, like the Investment Manager, are direct or indirect subsidiaries of Ameriprise Financial and are registered with the appropriate respective regulators and, where required, the SEC and the Commodity Futures Trading Commission in the United States.

Pursuant to some of these arrangements or relationships, certain personnel of Columbia Management and other Affiliates may serve as “associated persons” or officers of the Investment Manager and, in this capacity, subject to the oversight and supervision of the Investment Manager and consistent with the investment objectives, policies and limitations set forth in this prospectus and the Fund's SAI, and with the Investment Manager’s and the Funds’ compliance policies and procedures, may provide such services to the Fund.

Portfolio Managers

Information about the portfolio managers primarily responsible for overseeing the Fund’s investments is shown below. The SAI provides additional information about the portfolio managers, including information relating to compensation, other accounts managed by the portfolio managers, and ownership by the portfolio managers of Fund shares.

Portfolio Management	Title	Role with Fund	Service with the Fund Since
Stephen Kusmierczak, CFA	International Team Head, Portfolio Manager and Analyst	Lead Portfolio Manager or Co-Portfolio Manager since 2016	2001
Hans F. Stege	Portfolio Manager and Analyst	Co-Portfolio Manager since 2019	2017

Mr. Kusmierczak has been associated with the Investment Manager or its predecessors as an investment professional since 2001, has been President or Co-President of the Trust since 2020, and was a Vice President of the Trust from 2011-2020. Mr. Kusmierczak began his investment career in 1999 and earned a B.A. from Bowdoin College and an M.P.A. from the Princeton School of Public and International Affairs.

Mr. Stege has been associated with the Investment Manager or its predecessors as an investment professional since 2017 and has been a Vice President of the Trust since March 2020. Prior to joining the Investment Manager, Mr. Stege was a partner and research analyst at another investment firm, and also worked as a senior analyst for an energy consulting firm. Mr. Stege began his investment career in 2014 and earned a B.A. from Dartmouth College and an M.B.A. from the University of Chicago Booth School of Business.

The Administrator

Columbia Wanger Asset Management, LLC is responsible for overseeing the administrative operations of the Fund, including the general supervision of the Fund’s operations, coordination of the Fund’s service providers, and the provision of office facilities and related clerical and administrative services. The Administrator retains the Sub-Administrator to perform many of these services (including fund accounting), and pays a fee for the services of the Sub-Administrator. The Fund pays the Administrator a fee for its services, plus certain out-of-pocket expenses. The fee is calculated as an annual percentage of the Trust’s aggregate average daily net assets and is paid monthly, as follows:

Annual Administration Fee, as a % of Aggregate Daily Net Assets of the Trust:
Up to $8 billion	0.050%
$8 billion to $16 billion	0.040%
$16 billion to $35 billion	0.030%
$35 billion to $45 billion	0.025%
$45 billion and over	0.015%

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The Distributor

Shares of the Fund are distributed by Columbia Management Investment Distributors, Inc., which is located at 290 Congress Street, Boston, MA 02210. The Distributor is a registered broker-dealer and an indirect, wholly-owned subsidiary of Ameriprise Financial. The Distributor and its affiliates may pay commissions, distribution and service fees and/or other compensation to entities, including Ameriprise Financial affiliates, for selling shares and providing services to investors.

The Transfer Agent

Columbia Management Investment Services Corp. is a registered transfer agent and wholly-owned subsidiary of Ameriprise Financial. The Transfer Agent is located at 290 Congress Street, Boston, MA 02210, and its responsibilities include processing purchases, redemptions and exchanges of Fund shares, calculating and paying distributions, maintaining shareholder records, preparing account statements and providing customer service. The Transfer Agent has engaged DST Asset Manager Solutions, Inc. to provide various shareholder or “sub-transfer agency” services. In addition, the Transfer Agent enters into agreements with various financial intermediaries through which you may hold Fund shares, pursuant to which the Transfer Agent pays these financial intermediaries for providing certain shareholder services. Depending on the type of account, the Fund pays the Transfer Agent a per account fee for each open account and compensates the Transfer Agent for certain out-of-pocket expenses, including certain payments to financial intermediaries through which shares are held. In addition, subject to certain limitations, the Fund compensates the Transfer Agent for payments made to financial intermediaries for the shareholder services that the intermediaries provide, in amounts that vary by share class and with the type of intermediary and the type of shareholder services provided. The Transfer Agent is contractually obligated to oversee such intermediaries for the purpose of reasonably assuring their compliance with applicable law and the terms of their agreements to provide the shareholder services. For more information about Shareholder Services fees, see Choosing a Share Class — Financial Intermediary Compensation.

Other Roles and Relationships of Ameriprise Financial and its Affiliates — Certain Conflicts of Interest

This section describes certain actual and potential conflicts of interest that arise from the financial services activities of Ameriprise Financial and its affiliates. Ameriprise Financial is a major financial services company, engaged in a broad range of financial activities beyond the fund-related activities of the Investment Manager, including: insurance, broker-dealer (sales and trading), asset management and financial services. As a consequence of these activities, Ameriprise Financial or its affiliates may have interests arising from their other business lines that conflict with the interests of the Fund. These activities may also, from time to time, place certain investment constraints on the management of the Fund that might not otherwise arise.

As described in More Information About the Fund - Primary Service Provider Contracts, the Investment Manager, Administrator, Sub-Administrator, Distributor and Transfer Agent are all affiliates of Ameriprise Financial. In addition to the services that they provide to the Fund, they also provide substantially similar services (for which they are compensated) to other clients and customers, including the Columbia Funds. Ameriprise Financial and its other affiliates may also provide services (for which they are compensated) to the Fund, other Columbia Funds or other clients and customers.

Examples of activities that could lead to conflicts of interest and/or impose limitations that could affect the Fund include the following:

■ the Investment Manager and other Ameriprise Financial affiliates may receive compensation and other benefits related to the management/administration of the Fund and the other Columbia Funds and the sale of their shares;

■ there may be competition for limited investment opportunities that must be allocated among the Fund, the other Columbia Funds and other clients and customers of the Investment Manager (which can include affiliates of the Investment Manager) that may have the same or similar investment objectives as the Fund;

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■ management of the Fund may diverge from other Columbia Funds or other clients and customers of the Investment Manager or Ameriprise Financial affiliates, for example, advice given to the Fund may differ from, or conflict with, advice given to other funds or accounts;

■ there may be regulatory or investment restrictions imposed on the investment activities of the Investment Manager arising from the activities or holdings of other Columbia Funds or other clients or customers of the Investment Manager or Ameriprise Financial and its affiliates, for example, caps on the aggregate amount of certain types of investments or in holdings of particular portfolio companies that may be made by affiliated entities, including the Fund;

■ Ameriprise Financial or its affiliates may have potentially conflicting relationships with companies and other entities in which the Fund invests; and

■ there may be regulatory and other restrictions relating to the sharing of information between Ameriprise Financial and its affiliates, including the Investment Manager, for example, if an affiliated entity were in possession of non-public information, the Investment Manager might be prohibited by law from using that information in connection with the management of the Fund.

The Investment Manager and Ameriprise Financial have adopted various policies and procedures that are intended to identify, monitor and address conflicts of interest. However, there is no absolute assurance that these policies, procedures and disclosures will be effective.

Additional information about Ameriprise Financial and the types of conflicts of interest and other matters referenced above is set forth in the Investment Advisory and Other Services – Other Roles and Relationships of Ameriprise Financial and Affiliates – Certain Conflicts of Interest section of the SAI. Investors in the Fund should carefully review these disclosures and consult with their financial advisor if they have any questions.

Certain Legal Matters

Ameriprise Financial and certain of its affiliates are involved in the normal course of business in legal proceedings which include regulatory inquiries, arbitration and litigation, including class actions concerning matters arising in connection with the conduct of its activities as a diversified financial services firm. Ameriprise Financial believes that the Fund is not currently the subject of, and that neither Ameriprise Financial nor any of its affiliates are the subject of, any pending legal, arbitration or regulatory proceedings that are likely to have a material adverse effect on the Fund or the ability of Ameriprise Financial or its affiliates to perform under their contracts with the Fund. Information regarding certain pending and settled legal proceedings may be found in the Fund’s shareholder reports and in the SAI. Additionally, Ameriprise Financial is required to make quarterly (10-Q), annual (10-K) and, as necessary, 8-K filings with the SEC on legal and regulatory matters that relate to Ameriprise Financial and its affiliates. Copies of these filings may be obtained by accessing the SEC website at sec.gov.

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Choosing a Share Class

The Funds

The Columbia Acorn Funds and the other Columbia Funds generally share the same policies and procedures for investor services, as described below. Together, the Fund and the other Columbia Acorn Funds, along with the Columbia Funds, are referred to herein as the Funds.

Funds Contact Information

Additional information about the Funds, including sales charges and other class features and policies, can be obtained, free of charge, at columbiathreadneedleus.com,* by calling toll-free 800.345.6611, or by writing (regular mail) to Columbia Management Investment Services Corp., P.O. Box 219104, Kansas City, MO 64121-9104 or (express mail) Columbia Management Investment Services Corp., c/o DST Asset Manager Solutions, Inc., 430 W 7^th Street, Ste 219104, Kansas City, MO 64105-1407.

* The website references in this prospectus are inactive links and information contained in or otherwise accessible through the referenced websites does not form a part of this prospectus.

 FUNDamentals

Financial Intermediaries

The term “financial intermediary” refers to the selling and servicing agents that are authorized to sell and/or service shares of the Funds. Financial intermediaries include broker-dealers and financial advisors as well as firms that employ broker-dealers and financial advisors, including, for example, brokerage firms, banks, investment advisers, third party administrators and other firms in the financial services industry.

Omnibus Accounts

The term “omnibus account” refers to a financial intermediary’s account with the Fund (held directly through the Transfer Agent) that represents the combined holdings of, and transactions in, Fund shares of one or more clients of the financial intermediary (beneficial Fund shareholders). Omnibus accounts are held in the name of the financial intermediaries and not in the name of the beneficial Fund shareholders invested in the Fund through omnibus accounts.

Retirement Plans and Omnibus Retirement Plans

The term “retirement plan” refers to retirement plans created under Sections 401(a), 401(k), 457 and 403(b) of the Internal Revenue Code of 1986, as amended (the Code), and non-qualified deferred compensation plans governed by Section 409A of the Code and similar plans, but does not refer to individual retirement plans, such as traditional IRAs and Roth IRAs. The term “omnibus retirement plan” refers to a retirement plan that has a plan-level or omnibus account with the Transfer Agent.

Networked Accounts

Networking, offered by the Depository Trust & Clearing Corporation’s Wealth Management Services (WMS), is the industry standard IT system for mutual fund account reconciliation and dividend processing.

Summary of Share Class Features

Each share class has its own investment eligibility criteria, cost structure and other features. You may not be eligible to invest in every share class. Your financial intermediary may not make every share class available or may cease to make available one or more share classes of the Fund. The share class you select through your financial intermediary may have higher fees and/or sales charges than other classes of shares available through other financial intermediaries. An investor transacting in a class of Fund shares without any front-end sales charge, contingent deferred sales charge (CDSC), or other asset-based fee for sales or distribution, such as a Rule 12b-1 fee, may be required to pay a commission to the financial intermediary for effecting such transactions. Each investor’s personal situation is different and you may wish to discuss with your financial intermediary the share classes the Fund offers, which share classes are available to you and which share class(es) is/are appropriate for you. In all instances, it is your responsibility to notify your financial intermediary or (for Direct-at-Fund Accounts, as

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defined below) the Fund at the time of purchase of any relationship or other facts that may qualify you for sales charge waivers or discounts. The Fund, the Distributor and the Transfer Agent do not provide investment advice or make recommendations regarding Fund share classes. Your financial intermediary may provide advice and recommendations to you, such as which share class(es) is/are appropriate for you.

When deciding which class of shares to buy, you should consider, among other things:

■ The amount you plan to invest.

■ How long you intend to remain invested in the Fund.

■ The fees (e.g., sales charge or “load”) and expenses for each share class.

■ Whether you may be eligible for a reduction or waiver of sales charges when you buy or sell shares.

 FUNDamentals

Front-End Sales Charge Calculation

The front-end sales charge is calculated as a percentage of the offering price.

■ The net asset value (NAV) per share is the price of a share calculated by the Fund every business day.

■ The offering price per share is the NAV per share plus any front-end sales charge (or load) that applies.

The dollar amount of any applicable front-end sales charge is the difference between the offering price of the shares you buy and the NAV of those shares. To determine the front-end sales charge you will pay when you buy Class A shares, the Fund will add the amount of your investment to the value of your account (and any other accounts eligible for aggregation of which you or your financial intermediary notifies the Fund) and base the sales charge on the aggregate amount. For information on account value aggregation, sales charge waivers and other important information, see Choosing a Share Class — Reductions/Waivers of Sales Charges.

 FUNDamentals

Contingent Deferred Sales Charge

A contingent deferred sales charge (CDSC) is a sales charge applied at the time you sell your shares, unlike a front-end sales charge that is applied at the time of purchase. A CDSC can vary based on the length of time that you have held your shares. A CDSC is applied to the NAV at the time of your purchase or sale, whichever is lower, and will not be applied to any shares you receive through Fund distribution reinvestments or any amount that represents appreciation in the value of your shares. For purposes of calculating a CDSC, the start of the holding period is generally the first day of the month in which your purchase was made.

When you place an order to sell shares of a class that has a CDSC, the Fund will first redeem any shares that are not subject to a CDSC, followed by those you have held the longest. This means that if a CDSC is imposed, you cannot designate the individual shares being redeemed for U.S. federal income tax purposes. You should consult your tax advisor about the tax consequences of investing in the Fund. In certain circumstances, the CDSC may not apply. See Choosing a Share Class — Reductions/Waivers of Sales Charges for details.

Share Class Features

The following summarizes the primary features of Class A, Class Adv, Class C, Class Inst, Class Inst2, Class Inst3, and Class R shares.

Not all Funds offer every class of shares. The Fund offers the class(es) of shares set forth on the cover of this prospectus and may offer other share classes through a separate prospectus. Although certain share classes are generally closed to new and/or existing investors, information relating to these share classes is included in the table below because certain qualifying purchase orders are permitted, as described below.

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The sales charge reductions and waivers available to investors who purchase and hold their Fund shares through different financial intermediaries may vary. Appendix A describes financial intermediary-specific reductions and/or waiver policies. A shareholder transacting in Fund shares through a financial intermediary identified in Appendix A should carefully read the terms and conditions of Appendix A. A reduction and/or waiver that is specific to a particular financial intermediary is not available to Direct-at-Fund Accounts, as defined below, or through another financial intermediary. The information in Appendix A may be provided by, or compiled from or based on information provided by the financial intermediaries identified in Appendix A. To obtain additional information regarding any sales charge reduction and/or waiver described in Appendix A, and to ensure that you receive any such reductions or waivers that may be available to you, please consult your financial intermediary.

Share Class	Eligible Investors; Minimum Initial Investments; Conversion Features(a)	Front-End Sales Charges(b)	Contingent Deferred Sales Charges (CDSCs)(b)	Sales Charge Reductions/Waivers	Maximum Distribution and/or Service (12b-1) Fees(c)
Class A	Eligibility: Available to the general public for investment Minimum Initial Investment: $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts (as described below))	5.75% maximum, declining to 0.00% on investments of $1 million or more	CDSC on certain investments of between $1 million and $50 million redeemed within 18 months after purchase charged as follows: • 1.00% CDSC if redeemed within 12 months after purchase and • 0.50% CDSC if redeemed more than 12, but less than 18, months after purchase	Reductions: yes, see Choosing a Share Class — Reductions/Waivers of Sales Charges – Class A Shares Front-End Sales Charge Reductions Waivers: yes, on Fund distribution reinvestments. For additional waivers, see Choosing a Share Class — Reductions/Waivers of Sales Charges – Class A Shares Front-End Sales Charge Waivers, as well as Choosing a Share Class — CDSC Waivers – Class A and Class C Financial intermediary-specific waivers are also available, see Appendix A	Service Fee: 0.25%
Class Adv	Eligibility: Available only to (i) omnibus retirement plans, including self-directed brokerage accounts within omnibus retirement plans that clear through institutional no transaction fee (NTF) platforms; retirement plans; (ii) trust companies or similar institutions; (iii) broker-dealers, banks, trust companies and similar institutions that clear Fund share transactions for their client or customer investment advisory or similar accounts through designated financial intermediaries and their mutual fund trading platforms that have been granted specific written authorization from the Transfer Agent with respect to Class Adv eligibility apart from selling, servicing or similar agreements; (iv) 501(c)(3) charitable organizations; (v) 529 plans; (vi) health savings accounts; (vii) investors participating in a fee-based advisory program sponsored by a financial intermediary or other entity that is not compensated by the Fund for those services, other than payments for shareholder servicing or sub-accounting performed in place	None	None	N/A	None

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Share Class	Eligible Investors; Minimum Initial Investments; Conversion Features(a)	Front-End Sales Charges(b)	Contingent Deferred Sales Charges (CDSCs)(b)	Sales Charge Reductions/Waivers	Maximum Distribution and/or Service (12b-1) Fees(c)
	of the Transfer Agent; and (viii) commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Adv shares within such platform. Minimum Initial Investment: None, except in the case of (viii) above, which is $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts)
Class C	Eligibility: Available to the general public for investment Minimum Initial Investment: $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts) Conversion Feature: Yes. Effective April 1, 2021, Class C shares generally automatically convert to Class A shares of the same Fund in the month of or the month following the 8-year anniversary of the Class C shares purchase date. Prior to April 1, 2021, Class C shares generally automatically converted to Class A shares of the same Fund in the month of or the month following the 10-year anniversary of the Class C shares purchase date.(a)	None	1.00% on certain investments redeemed within one year of purchase	Waivers: yes, on Fund distribution reinvestments. For additional waivers, see Choosing a Share Class — CDSC Waivers – Class A and Class C Financial intermediary-specific CDSC waivers are also available, see Appendix A	Distribution Fee: 0.75% Service Fee: 0.25%
Class Inst	Eligibility: Available only to certain eligible investors, which are subject to different minimum investment requirements, ranging from $0 to $2,000, including investors who purchase Fund shares through commissionable brokerage platforms where the financial intermediary holds the shares in an omnibus account and, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst shares within such platform; closed to (i) accounts of financial intermediaries that clear Fund share transactions for their client or customer accounts through designated financial intermediaries and their mutual fund	None	None	N/A	None

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Share Class	Eligible Investors; Minimum Initial Investments; Conversion Features(a)	Front-End Sales Charges(b)	Contingent Deferred Sales Charges (CDSCs)(b)	Sales Charge Reductions/Waivers	Maximum Distribution and/or Service (12b-1) Fees(c)
	trading platforms that have been given specific written notice from the Transfer Agent of the termination of their eligibility for new purchases of Class Inst shares and (ii) omnibus group retirement plans, subject to certain exceptions(d) Minimum Initial Investment: See Eligibility above
Class Inst2	Eligibility: Available only to (i) certain registered investment advisers and family offices that clear Fund share transactions for their client or customer accounts through designated financial intermediaries and their mutual fund trading platforms that have been granted specific written authorization from the Transfer Agent with respect to Class Inst2 eligibility apart from selling, servicing or similar agreements; (ii) omnibus retirement plans(d); (iii) health savings accounts, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst2 shares within such platform and that Fund shares are held in an omnibus account; and (iv) institutional investors that are clients of the Columbia Threadneedle Global Institutional Distribution Team that invest in Class Inst2 shares for their own account through platforms approved by the Distributor or an affiliate thereof to offer and/or service Class Inst2 shares within such platform. Minimum Initial Investment: None	None	None	N/A	None
Class Inst3	Eligibility: Available to: (i) group retirement plans that maintain plan-level or omnibus accounts with the Fund(d); (ii) institutional investors that are clients of the Columbia Threadneedle Global Institutional Distribution Team that invest in Class Inst3 shares for their own account through platforms approved by the Distributor or an affiliate thereof to offer and/or service Class Inst3 shares within such platform; (iii) collective trust funds; (iv) affiliated or unaffiliated mutual funds (e.g., funds operating as funds-of-funds); (v) fee-based platforms of financial intermediaries (or the clearing intermediary they trade through) that have an agreement with the	None	None	N/A	None

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Share Class	Eligible Investors; Minimum Initial Investments; Conversion Features(a)	Front-End Sales Charges(b)	Contingent Deferred Sales Charges (CDSCs)(b)	Sales Charge Reductions/Waivers	Maximum Distribution and/or Service (12b-1) Fees(c)
	Distributor or an affiliate thereof that specifically authorizes the financial intermediary to offer and/or service Class Inst3 shares within such platform, provided also that Fund shares are held in an omnibus account; (vi) commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst3 shares within such platform and that Fund shares are held in an omnibus account; (vii) health savings accounts, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst3 shares within such platform and that Fund shares are held in an omnibus account; and (viii) bank trust departments, subject to an agreement with the Distributor that specifically authorizes offering Class Inst3 shares and provided that Fund shares are held in an omnibus account. In each case above where noted that Fund shares are required to be held in an omnibus account, the Distributor, may, in its discretion, determine to waive this requirement. Minimum Initial Investment: No minimum for the eligible investors described in (i), (iii), (iv) and (v) above; $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts) for the eligible investors described in (vi) above; and $1 million for all other eligible investors, unless waived in the discretion of the Distributor
Class R	Eligibility: Available only to eligible retirement plans, health savings accounts and, in the sole discretion of the Distributor, other types of retirement accounts held through platforms maintained by financial intermediaries approved by the Distributor Minimum Initial Investment: None	None	None	N/A	Distribution Fee: 0.50%

(a) For more information on the conversion of Class C shares to Class A shares, see Choosing a Share Class — Sales Charges and Commissions — Class C Shares —Conversion to Class A Shares.

(b) For more information on applicable sales charges, see Choosing a Share Class — Sales Charges and Commissions, and for information about certain exceptions to these sales charges, see Choosing a Share Class — Reductions/Waivers of Sales Charges.

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(c) These are the maximum applicable distribution and/or service fees under the Fund’s Rule 12b-1 plan. Because these fees are paid out of Fund assets on an ongoing basis, over time these fees will increase the cost of your investment and may cost you more than paying other types of distribution and/or service fees. For more information on distribution and service fees, see Choosing a Share Class — Distribution and Service Fees.

(d) These share classes are closed to new accounts generally or to new accounts of certain categories of investors, subject to certain conditions, as summarized below and described in more detail under Buying, Selling and Exchanging Shares — Buying Shares — Eligible Investors:

•  Class Inst Shares: Financial intermediaries that clear Fund share transactions through designated financial intermediaries and their mutual fund trading platforms that were given specific written notice from the Transfer Agent of the termination, effective March 29, 2013, of their eligibility for new purchases of Class Inst shares and omnibus retirement plans are not permitted to establish new Class Inst accounts, subject to certain exceptions. Omnibus retirement plans that opened and, subject to exceptions, funded a Class Inst account as of close of business on March 28, 2013, and have continuously held Class Inst shares in such account after such date, may generally continue to make additional purchases of Class Inst shares, open new Class Inst accounts and add new participants. In certain circumstances and in the sole discretion of the Distributor, omnibus retirement plans affiliated with a grandfathered plan may also open new Class Inst accounts. Accounts of financial intermediaries (other than omnibus retirement plans) that clear Fund share transactions for their client or customer accounts through designated financial intermediaries and their mutual fund trading platforms are not permitted to establish new Class Inst accounts or make additional purchases of Class Inst shares (other than through reinvestment of distributions).

•  Class Inst2 Shares. Shareholders with Class Inst2 accounts funded before November 8, 2012 who do not satisfy the current eligibility criteria for Class Inst2 shares may not establish new Class Inst2 accounts but may continue to make additional purchases of Class Inst2 shares in existing accounts. In addition, investment advisory programs and similar programs that opened a Class Inst2 account as of May 1, 2010, and continuously hold Class Inst2 shares in such account after such date, may generally not only continue to make additional purchases of Class Inst2 shares but also open new Class Inst2 accounts and add new shareholders in the program.

•  Class Inst3 Shares: Shareholders with Class Inst3 accounts funded before November 8, 2012 who do not satisfy the current eligibility criteria for Class Inst3 shares may not establish new accounts for such share class but may continue to make additional purchases of Class Inst3 shares in existing accounts.

Sales Charges and Commissions

Sales charges, commissions, and distribution fees compensate financial intermediaries (typically your financial advisor) for selling shares to you, and service fees compensate financial intermediaries for maintaining and servicing the shares held in your account with them. Distribution and service fees are discussed in a separate sub-section below. Depending on which share class you choose and the financial intermediary through which you purchase your shares, you may pay these charges at potentially different levels at the outset as a front-end sales charge, at the time you sell your shares as a CDSC and/or over time in the form of distribution and/or service fees. You may be required to pay brokerage commissions and other fees to financial intermediaries when transacting in any class of Fund shares, including those that do not assess any front-end sales charge, contingent deferred sales charge, or other asset-based fee for sales or distribution. Such brokerage commissions and other fees are set by the financial intermediary.

As described in more detail below, Class A shares have a front-end sales charge, which is deducted from your purchase price when you buy your shares, and results in a smaller dollar amount being invested in the Fund than the purchase price you pay (unless you qualify for a waiver or reduction of the sales charge). The Fund’s other share classes do not have a front-end sales charge, so the full amount of your purchase price is invested in those classes. Class A shares have lower ongoing distribution and/or service fees than Class C and Class R shares of the Fund. Over time, Class C and Class R shares can incur distribution and/or service fees that are equal to or more than the front-end sales charge and the distribution and/or service fees you would pay for Class A shares. Although the full amount of your purchase price of Class C and Class R shares is invested in a Fund, your return on this money will be reduced by the expected higher annual expenses of Class C and Class R shares. In this regard, note that effective April 1, 2021, Class C shares will generally automatically convert to Class A shares of the same Fund in the month of or the month following the 8-year anniversary of the Class C shares purchase date (prior to April 1, 2021, the 10-year anniversary of such date). The Fund may convert Class C shares held through a financial intermediary to Class A shares sooner in connection with the withdrawal of Class C shares of the Fund from the financial intermediary’s platform or accounts. No sales charge or other charges will apply in connection with such conversions, and the conversions are free from U.S. federal income tax. Once your Class C shares convert to Class A shares, your total returns from an investment in the Fund may increase as a result of the lower operating costs of Class A shares. Class Adv, Class Inst, Class Inst2 and Class Inst3 shares of the Fund do not have distribution and/or service fees.

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Whether the ultimate cost is higher for one share class over another depends on the amount you invest, how long you hold your shares, the fees (i.e., sales charges) and expenses of the class and whether you are eligible for reduced or waived sales charges, if available. You are responsible for choosing the share class most appropriate for you after taking into account your share class eligibility, class-specific features, and any applicable reductions in, or waivers of, sales charges. For more information, see Choosing a Share Class – Reductions/Waivers of Sales Charges. We encourage you to consult with a financial advisor who can help you with your investment decisions. Please contact your financial intermediary for more information about services, fees and expenses, and other important information about investing in the Fund, as well as with any questions you may have about your investing options. In all instances, it is your responsibility to notify your financial intermediary or (for Direct-at-Fund Accounts, as defined below) the Fund at the time of purchase of any relationship or other facts that may qualify you for sales charge waivers or discounts.

Class A Shares — Front-End Sales Charge

Unless your purchase qualifies for a waiver (e.g., you buy the shares through reinvested Fund dividends or distributions or subject to an applicable financial intermediary-specific waiver), you will pay a front-end sales charge when you buy Class A shares, resulting in a smaller dollar amount being invested in a Fund than the purchase price you pay. The Class A shares sales charge is waived on Class C shares converted to Class A shares. For more information about sales charge waivers and reduction opportunities, see Choosing a Share Class — Reductions/Waivers of Sales Charges and Appendix A.

The Distributor receives the sales charge and re-allows (or pays) a portion of the sales charge to the financial intermediary through which you purchased the shares. The Distributor retains the balance of the sales charge.

The front-end sales charge you will pay on Class A shares:

■ depends on the amount you are investing (generally, the larger the investment, the smaller the percentage sales charge), and

■ is based on the total amount of your purchase and the value of your account (and any other accounts eligible for aggregation of which you or your financial intermediary notifies the Fund).

The table below presents the front-end sales charge as a percentage of both the offering price and the net amount invested.

Class A Shares — Front-End Sales Charge — Breakpoint Schedule
Breakpoint Schedule For:	Dollar amount of shares bought(a)	Sales charge as a % of the offering price(b)	Sales charge as a % of the net amount invested(b)	Amount retained by or paid to financial intermediaries as a % of the offering price
Class A Shares	$0–$49,999	5.75%	6.10%	5.00%
	$50,000–$99,999	4.50%	4.71%	3.75%
	$100,000–$249,999	3.50%	3.63%	3.00%
	$250,000–$499,999	2.50%	2.56%	2.15%
	$500,000–$999,999	2.00%	2.04%	1.75%
	$1,000,000 or more	0.00%	0.00%	0.00%(c)

(a) Purchase amounts and account values may be aggregated among all eligible Fund accounts for the purposes of this table. See Choosing a Share Class — Reductions/Waivers of Sales Charges for a discussion of account value aggregation.

(b) Because the offering price is calculated to two decimal places, the dollar amount of the sales charge as a percentage of the offering price and your net amount invested for any particular purchase of Fund shares may be higher or lower depending on whether downward or upward rounding was required during the calculation process. Purchase price includes the sales charge.

(c) For information regarding cumulative commissions paid to your financial intermediary when you buy $1 million or more of Class A shares of a Fund, see Class A Shares — Commissions below.

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Class A Shares — CDSC

In some cases, you'll pay a CDSC if you sell Class A shares that you purchased without a front-end sales charge.

■ If you purchased Class A shares without an initial sales charge because your accounts aggregated between $1 million and $50 million at the time of purchase, you will incur a CDSC if you redeem those shares within 18 months after purchase, which is charged as follows: 1.00% CDSC if shares are redeemed within 12 months after purchase; and 0.50% CDSC if shares are redeemed more than 12, but less than 18, months after purchase.

■ Subsequent Class A share purchases that bring your aggregate account value to $1 million or more (but less than $50 million) will also be subject to a CDSC if you redeem them within the time periods noted above.

Class A Shares — Commissions

The Distributor may pay your financial intermediary an up-front commission when you buy Class A shares. The Distributor generally funds the commission through the applicable sales charge you paid. For more information, see Class A Shares — Front-End Sales Charge above.

The Distributor may also pay your financial intermediary a cumulative commission when you buy Class A shares in amounts not subject to a front-end sales charge, according to the following schedules (assets initially purchased into Class A shares of Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund and Columbia U.S. Treasury Index Fund that were purchased without the application of a front-end sales charge are excluded for purposes of calculating a financial intermediary’s commission under these schedules):

Class A Shares — Commission Schedule (Paid by the Distributor to Financial Intermediaries)
Purchase Amount	Commission Level* (as a % of net asset value per share)
$1 million – $2,999,999	1.00%
$3 million – $49,999,999	0.50%
$50 million or more	0.25%

* The commission level applies to the applicable asset level; therefore, for example, for a purchase of $5 million, the Distributor would pay a commission of 1.00% on the first $2,999,999 and 0.50% on the balance.

Class C Shares — Front-End Sales Charge

You do not pay a front-end sales charge when you buy Class C shares, but you may pay a CDSC when you sell Class C shares. Although Class C shares do not have a front-end sales charge, over time Class C shares can incur distribution and/or service fees that are equal to or more than the front-end sales charge and distribution and/or service fees you would pay for Class A shares. Thus, although the full amount of your purchase of Class C shares is invested in a Fund, any positive investment return on this money may be partially or fully offset by the expected higher annual expenses of Class C shares.

Class C Shares — Conversion to Class A Shares

Effective April 1, 2021, Class C shares of a Fund generally automatically convert to Class A shares of the same Fund in the month of or the month following the 8-year anniversary of the Class C shares purchase date. Prior to April 1, 2021, Class C shares of a Fund generally automatically converted to Class A shares of the same Fund in the month of or in the month following the 10-year anniversary of the Class C shares purchase date. Class C shares held through a financial intermediary in an omnibus account will be converted (pursuant to the financial intermediary’s Class C conversion policy, including those disclosed in Appendix A, which may differ from the Fund’s policy described here) provided that the intermediary is able to track individual shareholders’ holding periods. It is the financial intermediary's (and not the Fund's) responsibility to keep records and to ensure that the shareholder holding period is calculated properly. Not all financial intermediaries are able to track individual shareholders' holding periods. For example, group retirement plans held through third-party intermediaries that hold Class C shares in an omnibus account may not track participant level share lot aging. Please consult with your financial intermediary about your

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eligibility for Class C share conversion. The Fund may convert Class C shares held through a financial intermediary to Class A shares sooner in connection with the withdrawal of Class C shares of the Fund from the financial intermediary's platform or accounts. Once your Class C shares convert to Class A shares, your total returns from an investment in the Fund may increase as a result of the lower operating costs of Class A shares.

The following rules apply to the automatic conversion of Class C shares to Class A shares:

■ Class C share accounts that are Direct-at-Fund Accounts and Networked Accounts for which the Transfer Agent (and not your financial intermediary) sends you Fund account transaction confirmations and statements, convert on or about the 15th day of the month (if the 15th is not a business day, then the next business day thereafter) that they become eligible for automatic conversion provided that the Fund has records that Class C shares have been held for the requisite time period.

■ For purposes of determining the month when your Class C shares are eligible for conversion, the start of the holding period is the first day of the month in which your purchase was made. Your financial intermediary may choose a different day of the month to convert Class C shares. Please contact your financial intermediary for more information on calculating the holding period.

■ Any shares you received from reinvested distributions on these shares generally will convert to Class A shares at the same time.

■ You’ll receive the same dollar value of Class A shares as the Class C shares that were automatically converted. Class C shares that you received from an exchange of Class C shares of another Fund will convert based on the day you bought the original shares.

■ In addition to the above automatic conversion of Class C to Class A shares policy, the Transfer Agent seeks to convert Class C shares as soon as administratively feasible, regardless of how long such shares have been owned, to Class A shares of the same Fund for Direct-at-Fund Accounts (as defined below) that do not or no longer have a financial intermediary assigned to them. Direct-at-Fund Accounts that do not have a financial intermediary assigned to them are not permitted to purchase Class C shares; Class C share purchase orders received by Direct-at-Fund Accounts that do not have a financial intermediary assigned to the account will automatically be invested in Class A shares of the same Fund.

■ No sales charge or other charges apply in connection with these automatic conversions, and the conversions are free from U.S. federal income tax.

Class C Shares — CDSC

You will pay a CDSC of 1.00% if you redeem Class C shares within 12 months of buying them unless you qualify for a waiver of the CDSC (e.g., the shares you are selling were purchased with reinvested Fund distributions). Redemptions of Class C shares are not subject to a CDSC if redeemed after 12 months. For more information, see Choosing a Share Class — Reductions/Waivers of Sales Charges.

Class C Shares — Commissions

Although there is no front-end sales charge when you buy Class C shares, the Distributor makes an up-front payment (which includes a sales commission and an advance of service fees) directly to your financial intermediary of up to 1.00% of the NAV per share when you buy Class C shares. A portion of this payment may be passed along to your financial advisor. The Distributor seeks to recover this payment through distribution fees of up to 0.75% and shareholder service fees of up to 0.25% it receives under the Fund's Rule 12b-1 plan during the first 12 months following the sale of Class C shares, and any applicable CDSC when you sell your shares. For more information, see Choosing a Share Class — Distribution and Service Fees.

Reductions/Waivers of Sales Charges

The availability of certain sales charge waivers and discounts will depend on whether you purchase your shares directly from the Fund (i.e., a Direct-at-Fund Account, as defined below) or through a financial intermediary. Financial intermediaries may have different policies and procedures regarding the availability of front-end sales charge and/or CDSC waivers. In all instances, it is your responsibility to notify your financial intermediary or (for Direct-at-Fund

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Accounts, as defined below) the Fund at the time of purchase of any relationship or other facts that may qualify you for sales charge waivers or discounts. In order to obtain waivers and discounts not available through a particular financial intermediary, shareholders will have to purchase Fund shares directly from the Fund (if permitted) or through a different financial intermediary. For a description of financial intermediary-specific sales charge reductions and/or waivers, see Appendix A.

Class A Shares Front-End Sales Charge Reductions

The Fund makes available two means of reducing the front-end sales charge that you may pay when you buy Class A shares of a Fund. These types of sales charge reductions are also referred to as breakpoint discounts.

First, through the right of accumulation (ROA), you may combine the value of eligible accounts (as described in the Eligible Accounts section below) maintained by you and members of your immediate family to reach a breakpoint discount level and apply a lower front-end sales charge to your purchase. To calculate the combined value of your eligible Fund accounts in the particular class of shares, the Fund will use the current public offering price per share. For purposes of obtaining a breakpoint discount through ROA, you may aggregate your and your “immediate family” members' ownership (as described in the FUNDamentals box below) of certain classes of shares held in certain account types, as described in the Eligible Accounts section below.

Second, by making a statement of intent to purchase additional shares (commonly referred to as a letter of intent (LOI)), you may pay a lower sales charge on all purchases of Class A shares made within 13 months after the date of your LOI. Your LOI must state the aggregate amount of purchases you intend to make in that 13-month period, which must be at least enough to reach the first (or next) breakpoint of the Fund. The required form of LOI may vary by financial intermediary, so please contact them directly for more information. Five percent of the purchase commitment amount will be placed in escrow. At the end of the 13-month period, the shares will be released from escrow, provided that you have invested the commitment amount. If you do not invest the commitment amount by the end of the 13 months, the remaining amount of the unpaid sales charge will be redeemed from the escrowed shares and the remaining balance released from escrow. To calculate the total value of the purchases you've made under an LOI, the Fund will use the historic cost (i.e., dollars invested and not current market value) of the shares held in each eligible account; reinvested dividends or capital gains, or purchases made through the reinstatement privilege do not count as purchases made under an LOI. For purposes of making an LOI to purchase additional shares, you may aggregate eligible shares owned by you or your immediate family members in eligible accounts, valued as of the day immediately before the initiation of your LOI.

You must request the reduced sales charge (whether through ROA or an LOI) when you buy shares. If you do not complete and file an LOI, or do not request the reduced sales charge at the time of purchase, you will not be eligible for the reduced sales charge. To obtain a breakpoint discount, you must notify your financial intermediary in writing at the time you buy your shares of each eligible account maintained by you and members of your immediate family, including accounts maintained through different financial intermediaries. You and your financial intermediary are responsible for ensuring that you receive discounts for which you are eligible. Please contact your financial intermediary with questions regarding application of the eligible discount to your account. You may be asked by your financial intermediary (or by the Fund if you hold your account directly with the Fund) for account statements or other records to verify your discount eligibility for new and subsequent purchases, including, when applicable, records for accounts opened with a different financial intermediary and records of accounts established by members of your immediate family.

The sales charge reductions available to investors who purchase and hold their Fund shares through different financial intermediaries may vary. For a description of such financial intermediary-specific sales charge reductions, see Appendix A.

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Choosing a Share Class (continued)

 FUNDamentals

Your “Immediate Family” and Account Value Aggregation

For purposes of obtaining a breakpoint discount for Class A shares, the value of your account will be deemed to include the value of all applicable shares in eligible Fund accounts that are held by you and your “immediate family,” which includes your spouse, domestic partner, parent, step-parent, legal guardian, child under 21, step-child under 21, father-in-law and mother-in-law, provided that you and your immediate family members share the same mailing address. Any Fund accounts linked together for account value aggregation purposes as of the close of business on September 3, 2010 will be permitted to remain linked together. Group retirement plan accounts are valued at the retirement plan level.

Eligible Accounts

The following accounts are eligible for account value aggregation as described above, provided that they are invested in Class A (excluding, in the case of Direct-at-Fund Accounts, Funds that do not assess a front-end sales charge, including Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund and Columbia U.S. Treasury Index Fund, unless such shares were purchased via an exchange from Class A shares of a Fund on which you paid the Class A share applicable front-end sales charge), Class C, Class E, Class Inst or Class V shares of a Fund, or non-retirement plan accounts invested in Class Adv, Class Inst2 or Class Inst3 shares of a Fund: individual or joint accounts; Roth and traditional Individual Retirement Accounts (IRAs); Simplified Employee Pension accounts (SEPs), Savings Investment Match Plans for Employees of Small Employers accounts (SIMPLEs) and Tax Sheltered Custodial Accounts (TSCAs); Uniform Gifts to Minors Act (UGMA)/Uniform Transfers to Minors Act (UTMA) accounts for which you, your spouse, or your domestic partner is parent or guardian of the minor child; revocable trust accounts for which you or an immediate family member, individually, is the beneficial owner/grantor; accounts held in the name of your, your spouse’s, or your domestic partner’s sole proprietorship or single owner limited liability company or S corporation; qualified retirement plan assets, provided that you are the sole owner of the business sponsoring the plan, are the sole participant (other than a spouse) in the plan, and have no intention of adding participants to the plan; and investments in wrap accounts.

The following accounts are not eligible for account value aggregation as described above: accounts of pension and retirement plans with multiple participants, such as 401(k) plans (which are combined to reduce the sales charge for the entire pension or retirement plan and therefore are not used to reduce the sales charge for your individual accounts); investments in 529 plans, donor advised funds, variable annuities, variable insurance products or managed separate accounts; charitable and irrevocable trust accounts; accounts holding shares of money market funds that used the Columbia brand before May 1, 2010; accounts invested in Class R shares of a Fund; and retirement plan accounts invested in Class Adv, Class Inst2 or Class Inst3 shares of a Fund.

Additionally, direct purchases of shares of Columbia Government Money Market Fund may not be aggregated for account value aggregation purposes; however, shares of Columbia Government Money Market Fund acquired by exchange from other Columbia Funds that assess a sales charge may be included in account value aggregation.

Class A Shares Front-End Sales Charge Waivers

There are no front-end sales charges on reinvested Fund distributions. The Class A shares sales charge is waived on conversions of Class C shares to Class A shares. The Distributor may waive front-end sales charges on purchases of Class A shares of the Funds by certain categories of investors, including Board members, certain employees of financial intermediaries, Fund portfolio managers, certain partners and employees of outside legal counsel to the Funds or the Board, separate accounts of an insurance company exempt from registration as an investment company under Section 3(c)(11) of the 1940 Act, registered broker-dealer firms that have an agreement with the Distributor purchasing Fund shares for their investment account only, and qualified employee benefit plan rollovers to Class A

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Choosing a Share Class (continued)

shares in the same Fund (see Appendix S to the SAI for details). For a more complete description of categories of investors who may purchase Class A shares of the Funds at NAV, without payment of any front-end sales charge that would otherwise apply, see Appendix S to the SAI.

In addition, certain types of purchases of Class A shares may be made at NAV. The Distributor may waive front-end sales charges on (i) purchases (including exchanges) of Class A shares in accounts of financial intermediaries that have entered into agreements with the Distributor to offer Fund shares to self-directed investment brokerage accounts that may or may not charge a transaction fee to customers; (ii) exchanges of Class Inst shares of a Fund for Class A shares of the Fund; (iii) purchases of Class A shares on brokerage mutual fund-only platforms of financial intermediaries that have an agreement with the Distributor that specifically authorizes the offering of Class A shares within such platform; (iv) purchases through certain wrap fee or other products or programs that involve fee-based compensation arrangements that have, or clear trades through a financial intermediary that has, a selling agreement with the Distributor; (v) purchases through state sponsored 529 Plans; (vi) purchases through banks, trust companies, and thrift institutions acting as fiduciaries; (vii) purchases through certain employee benefit plans and certain qualified deferred compensation plans; and (viii) purchases of Class A shares in Direct-at-Fund Accounts (as defined below) that do not have a financial intermediary assigned to them. For a more complete description of these eligible transactions, see Appendix S to the SAI.

The sales charge waivers available to investors who purchase and hold their Fund shares through different financial intermediaries may vary. For a description of such financial intermediary-specific sales charge waivers, see Appendix A.

CDSC Waivers – Class A and Class C

You may be able to avoid an otherwise applicable CDSC when you sell Class A or Class C shares of the Fund. This could happen because of the way in which you originally invested in the Fund, because of your relationship with the Funds or for other reasons. For example, the CDSC will be waived on redemptions of shares: in the event of the shareholder's death; for which no sales commission or transaction fee was paid to an authorized financial intermediary at the time of purchase; purchased through reinvestment of dividends and capital gain distributions; that result from required minimum distributions taken from retirement accounts due to the shareholder reaching the qualified age based on applicable IRS regulations; that result from returns of excess contributions made to retirement plans or individual retirement accounts (subject to certain conditions); initially purchased by an employee benefit plan (for Class A shares) and that are not connected with a plan level termination (for Class C shares); in connection with the Fund's Small Account Policy (which is described in Buying, Selling and Exchanging Shares — Transaction Rules and Policies); held within Direct-at-Fund Accounts that do not have a financial intermediary assigned to them; and by certain other investors and in certain other types of transactions or situations. Restrictions may apply to certain accounts and certain transactions. The Distributor may, in its sole discretion, authorize the waiver of the CDSC for additional classes of investors. The Fund may change or cancel these terms at any time. Any change or cancellation applies only to future purchases. For a more complete description of the available waivers of the CDSC on redemptions of Class A or Class C shares, see Appendix S to the SAI.

The sales charge waivers available to investors who purchase and hold their Fund shares through different financial intermediaries may vary. For a description of such financial intermediary-specific sales charge waivers, see Appendix A.

Repurchases (Reinstatements)

As noted in the table below, you can redeem shares of certain classes (see Redeemed Share Class below) and use such redemption proceeds to buy shares of the Corresponding Repurchase Class without paying an otherwise applicable sales charge and/or CDSC (other than, in the case of Direct-at-Fund Accounts, redemptions from Funds that do not assess a front-end sales charge, including Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund and Columbia U.S. Treasury Index Fund, unless such shares were purchased via an exchange from Class A shares of a Fund on which you paid the Class A share applicable front-end sales charge) within 90 days, up to the amount of the redemption proceeds.

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Repurchases (Reinstatements)
Redeemed Share Class	Corresponding Repurchase Class
Class A	Class A
Class C	Class C

Any CDSC paid upon redemption of your Class A or Class C shares of a Fund will not be reimbursed.

To be eligible for the repurchase (or reinstatement) privilege, the purchase must be made into an account for the same owner, but does not need to be into the same Fund from which the shares were sold. The Transfer Agent, Distributor or their agents must receive a written reinstatement request from you or your financial intermediary within 90 days after the shares are redeemed. The purchase of the Corresponding Repurchase Class (as noted in the table above) through this repurchase (or reinstatement) privilege will be made at the NAV of such shares next calculated after the request is received in “good form.” Systematic withdrawals and purchases are excluded from this policy.

Restrictions and Changes in Terms and Conditions

Restrictions may apply to certain accounts and certain transactions. The Funds and/or the Distributor may change or cancel these terms and conditions at any time. Unless you provide your financial intermediary with information in writing about all of the factors that may count toward available reductions or waivers of an applicable sales charge, there can be no assurance that you will receive all of the reductions and waivers for which you may be eligible. To the extent your Fund account is held directly with the Fund, you should provide this information to the Fund when placing your purchase or redemption order. Please see Appendix A to this prospectus and Appendix S of the SAI for more information about sales charge waivers.

Distribution and Service Fees

The Board has approved, and the Columbia Acorn Funds have adopted, a distribution plan pursuant to Rule 12b-1 under the 1940 Act that sets the distribution and/or service fees that are periodically deducted from the Funds’ assets. These fees are calculated daily, may vary by share class and are intended to compensate the Distributor and/or eligible financial intermediaries for, with regard to distribution fees, selling Fund shares and, with regard to service fees, directly or indirectly providing services to shareholders. Because the fees are paid out of the Fund's assets on an ongoing basis, they will increase the cost of your investment over time.

The table below shows the maximum annual distribution and/or service fees (as an annual percentage of average daily net assets) and the combined amount of such fees applicable to each share class of the Columbia Acorn Funds:

	Distribution Fee	Service Fee	Combined Total
Class A	None	0.25%	0.25%
Class Adv	None	None	None
Class C	0.75%	0.25%	1.00%
Class Inst	None	None	None
Class Inst2	None	None	None
Class Inst3	None	None	None
Class R	0.50%	None	0.50%

The distribution and/or service fees for Class A, Class C, and Class R shares, as applicable, are subject to the requirements of Rule 12b-1 under the 1940 Act. The Distributor may retain these fees otherwise payable to financial intermediaries if the amounts due are below an amount determined by the Distributor in its sole discretion.

For Class A shares, the Distributor begins to pay these fees immediately after purchase, except in the following case, in which the Distributor begins to pay these fees 12 months after purchase: a purchase of Class A shares of $1 million or more that pay a Class A up-front commission to your financial intermediary and the financial intermediary has opted to receive such commission. The Distributor’s policy to otherwise begin to pay these fees immediately on

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Choosing a Share Class (continued)

Class A shares also applies to purchases of funds that do not pay an up-front sales commission on Class A shares, which includes Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund and Columbia U.S. Treasury Index Fund. For Class C shares, the Distributor begins to pay these fees 12 months after purchase. However, for Class C shares, financial intermediaries may opt to decline the up-front payment described in Choosing a Share Class – Sales Charges and Commissions – Class C Shares – Commissions and instead may receive these fees immediately after purchase. If the intermediary opts to receive the up-front payment, the Distributor retains the distribution and service fee for the first 12 months following the sale of Class C shares in order to recover the up-front payment made to financial intermediaries and to pay for other related expenses. For Class R shares, the Distributor begins to pay these fees immediately after purchase.

If you maintain shares of the Fund directly with the Fund, without working with a financial advisor or other financial intermediary, distribution and service fees may be retained by the Distributor as payment or reimbursement for incurring certain distribution and shareholder service related expenses.

Over time, these distribution and/or service fees will reduce the return on your investment and may cost you more than paying other types of sales charges. The Fund will pay these fees to the Distributor and/or to eligible financial intermediaries for as long as the distribution plan continues in effect, which is expected to be indefinitely. However, the Fund may reduce or discontinue payments at any time. Your financial intermediary may also charge you other additional fees for providing services to your account, which may be different from those described here.

Financial Intermediary Compensation

The Distributor, the Investment Manager and their affiliates make payments, from their own resources, to financial intermediaries, including other Ameriprise Financial affiliates, for marketing/sales support services relating to the Funds (Marketing Support Payments). Such payments are generally based upon one or more of the following factors: average net assets of the Funds attributable to that financial intermediary; gross sales of the Funds attributable to that financial intermediary; reimbursement of ticket charges (fees that a financial intermediary charges its representatives for effecting transactions in Fund shares); or a negotiated lump sum payment. While the financial arrangements may vary for each financial intermediary, Marketing Support Payments to any one financial intermediary are generally between 0.01% and 0.40% on an annual basis for payments based on average net assets of the Fund attributable to the financial intermediary, and between 0.05% and 0.25% on an annual basis for firms receiving a payment based on gross sales of the Funds attributable to the financial intermediary. The Distributor, the Investment Manager and their affiliates make payments with respect to a Fund or the Columbia Funds generally on a basis other than those described above or in larger amounts when dealing with certain financial intermediaries. Not all financial intermediaries receive Marketing Support Payments. The Distributor, the Investment Manager and their affiliates do not make Marketing Support Payments with respect to Class Inst3 shares of the Columbia Acorn Funds.

In addition, the Transfer Agent has certain arrangements in place to compensate financial intermediaries, including other Ameriprise Financial affiliates, that hold Fund shares through networked and omnibus accounts, including omnibus retirement plans, for services that they provide to beneficial Fund shareholders (Shareholder Services). Shareholder Services and related fees vary by financial intermediary and according to distribution channel and may include sub-accounting, sub-transfer agency, participant recordkeeping, shareholder or participant reporting, shareholder or participant transaction processing, maintenance of shareholder records, preparation of account statements and provision of customer service, and are not intended to include services that are primarily intended to result in the sale of Fund shares. Payments for Shareholder Services vary by financial intermediary and according to distribution channel, but generally are not expected, with certain limited exceptions, to exceed 0.40% of the average aggregate value of the Fund’s shares. Payments to financial intermediaries in excess of the amounts paid by the Fund are borne by the Distributor, the Investment Manager and/or their affiliates.

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Generally, each Fund in the Columbia Acorn Family of Funds compensates the Transfer Agent for payments made for Shareholder Services, for each share class except Class Inst3. Effective July 1, 2017, the Columbia Acorn Funds compensate the Transfer Agent for payments made for Shareholder Services as follows:

Financial Intermediary Distribution Channel	Fee Rate
Retirement	up to 0.18% of Fund assets held by intermediaries or platforms charging an asset-based fee, or $18 per account held by intermediaries or platforms charging a per account fee
Fund supermarket transaction fee (TF)	up to 0.12% of Fund assets held by intermediaries or platforms charging an asset-based fee, or $16 per account held for intermediaries or platforms charging a per account fee
Fund supermarket no-transaction fee (NTF)	up to 0.18% of Fund assets held by intermediaries or platforms charging an asset-based fee, or $18 per account held by intermediaries or platforms charging a per account fee
Bank	up to 0.10% of Fund assets held by intermediaries or platforms charging an asset-based fee, or $20 per account held by intermediaries or platforms charging a per account fee
Broker-dealer	up to 0.13% of Fund assets held by intermediaries or platforms charging an asset-based fee, or $16 per account held by intermediaries or platforms charging a per account fee

With respect to Class Inst2 and Class Inst3 shares of the Fund, total annual compensation payable to the Transfer Agent may not exceed, respectively, 0.07% and 0.02% of the average daily net assets of the Class. For additional details about the application of the Columbia Acorn Funds’ fee limits, please refer to the SAI.

The Transfer Agent does not pay financial intermediaries for Shareholder Services, and the Fund does not compensate the Transfer Agent for any Shareholder Services provided by financial intermediaries with respect to Class Inst3 shares of the Columbia Acorn Funds. The Fund believes that the fee levels paid to the Transfer Agent are reasonably related to the Shareholder Services provided, but payments may vary and there can be no assurance that the Fund will be able to identify with specificity the costs or particular Shareholder Services for which compensation is paid.

In addition to the payments described above, the Distributor, the Investment Manager and their affiliates typically make other payments or allow promotional incentives to certain broker-dealers to the extent permitted by the Securities and Exchange Commission (the SEC) and Financial Industry Regulatory Authority (FINRA) rules and by other applicable laws and regulations.

Amounts paid by the Distributor, the Investment Manager and their affiliates are paid out of their own resources and do not increase the amount paid by you or the Fund. You can find further details in the SAI about the payments made by the Distributor, the Investment Manager and their affiliates, as well as a list of the financial intermediaries, including Ameriprise Financial affiliates, to which the Distributor and the Investment Manager have agreed to make Marketing Support Payments and pay Shareholder Services fees.

Your financial intermediary may charge you fees and commissions in addition to those described in this prospectus. You should consult with your financial intermediary and review carefully any disclosure your financial intermediary provides regarding its services and compensation. Depending on the financial arrangement in place at any particular time, a financial intermediary and its financial advisors may have a conflict of interest or financial incentive for recommending the Fund or a particular share class over others.

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Buying, Selling and Exchanging Shares

Share Price Determination

The price you pay or receive when you buy, sell or exchange shares is the Fund's next determined net asset value (or NAV) per share for a given share class. The Fund calculates the NAV per share for each class of shares of the Fund at the end of each business day, with the value of the Fund's shares based on the total value of all of the securities and other assets that it holds as of such specified time.

 FUNDamentals

NAV Calculation

Each of the Fund's share classes calculates its NAV per share as follows:

NAV per share =  (Value of assets of the share class) – (Liabilities of the share class)
Number of outstanding shares of the class

 FUNDamentals

Business Days

A business day is any day that the New York Stock Exchange (NYSE) is open. A business day ends at (i) the scheduled close of the NYSE for such day (usually 4:00 p.m. Eastern Time or such other time as the NYSE may schedule), (ii) the scheduled close of the NYSE (usually 4:00 p.m. Eastern Time) on any business day on which the NYSE has an unscheduled close or intraday trading halt or other disruption, regardless of the time of such unscheduled close, halt or disruption or whether trading resumes, or (iii) such other time as the Board may from time to time determine. On holidays and other days when the NYSE is closed, the Fund’s NAV is not calculated and the Fund does not accept buy or sell orders. However, the value of the Fund’s assets may still be affected on such days to the extent that the Fund holds foreign securities that trade on days that foreign securities markets are open.

Equity securities are valued primarily on the basis of market quotations reported on stock exchanges and other securities markets around the world. Certain equity securities, debt securities and other assets are valued differently. For instance, short-term investments maturing in 60 days or less are valued primarily using the amortized cost method and those maturing in excess of 60 days are valued at the readily available market price. For a Fund organized as a fund-of-funds, its investments in other funds are valued at their NAVs. Market quotations are obtained from outside pricing services approved and monitored pursuant to a policy approved by the Fund’s Board.

If a market price is not readily available or is deemed not to reflect market value, the security will be valued in good faith based on a determination of the security's fair value pursuant to the Portfolio Pricing Policy approved by the Board. The Portfolio Pricing Policy provides that fair value determinations will be made using the methodology set forth in the Policy and deemed most appropriate under the circumstances and considering all available, relevant factors and indications of value. The Portfolio Pricing Policy provides that fair valuation may be used to price securities that trade on a foreign exchange when a significant event has occurred after the foreign exchange closes but before the time at which the Fund's share price is calculated. In addition, a statistical fair valuation process is applied daily to adjust prices of foreign securities traded on foreign exchanges in time zones different from the United States utilizing the services of a designated pricing vendor. Although the use of statistical fair valuation is intended to and may decrease opportunities for time zone arbitrage transactions, there can be no assurance that it will successfully decrease arbitrage opportunities. Please consult the SAI for more information on the factors to be considered in making fair value determinations; the significant events that may necessitate fair valuation of foreign securities; and the Fund's statistical fair valuation methodology.

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Buying, Selling and Exchanging Shares (continued)

When fair valuation is used to price securities, the values for those securities may be higher or lower than values used by another fund to price the security. Also, the use of fair valuation may cause the Fund's performance to diverge to a greater degree from the performance of various benchmarks used to compare the Fund's performance because benchmarks generally do not use fair valuation techniques. Because of the judgment involved in fair valuation decisions, there can be no assurance that the value ascribed to a particular security is accurate.

Transaction Rules and Policies

The Fund, the Distributor or the Transfer Agent may refuse any order to buy or exchange shares. If this happens, the Fund will return any money it received, but no interest will be paid on that money. Your financial intermediary may have rules and policies in place that are in addition to or different than those described below.

Order Processing

Orders to buy, sell or exchange Fund shares are processed on business days. Depending upon the class of shares, orders can be made by mail, by telephone or online. Orders received in “good form” by the Transfer Agent or your financial intermediary before the end of a business day are priced at the NAV per share (plus any applicable sales charge) of the Fund's applicable share class on that day. Orders received after the end of a business day will receive the next business day's NAV per share (plus any applicable sales charge). For Direct-at-Fund Accounts (as defined below), when a written order to buy, sell or exchange shares is sent to the Transfer Agent, the share price used to fill the order is the next price calculated by the Fund after the Transfer Agent receives the transaction request in “good form” at its transaction processing center (i.e., the Fund’s express mail address), not the P.O. Box provided for regular mail delivery. The market value of the Fund's investments may change between the time you submit your order and the time the Fund next calculates its NAV per share. The business day that applies to your order is also called the trade date.

“Good Form”

An order is in “good form” if the Transfer Agent or your financial intermediary has received payment (in the case of purchases) and all of the information and documentation it deems necessary to effect your order. For example, when you sell shares, “good form” means that your request (i) has complete instructions and written requests include the signatures of all account owners, (ii) is for an amount that is less than or equal to the shares in your account for which payment has been received and collected, (iii) has a Medallion Signature Guarantee for amounts greater than $100,000 and certain other transactions, as described below, and (iv) includes any other required documents completed and attached. For the documents required for sales by corporations, agents, fiduciaries, surviving joint owners and other legal entities, call 800.345.6611.

Medallion Signature Guarantees

The Transfer Agent may require a Medallion Signature Guarantee for your signature in order to process certain transactions, including if: (i) the transaction amount is over $100,000; (ii) you want your check made payable to someone other than the registered account owner(s); (iii) the address of record has changed within the last 30 days; (iv) you want the check mailed to an address other than the address of record; (v) you want proceeds to be sent according to existing bank account instructions not coded for outgoing Automated Clearing House (ACH) or wire, or to a bank account not on file; or (vi) you are changing legal ownership of your account.

A Medallion Signature Guarantee helps assure that a signature is genuine and not a forgery. A Medallion Signature Guarantee must be provided by an eligible guarantor institution including, but not limited to, the following: a bank, credit union, savings association, broker or dealer that participates in the Securities Transfer Association Medallion Program (STAMP), the Stock Exchange Medallion Program (SEMP) or the New York Stock Exchange Medallion Signature Program (MSP). For other transactions, the Transfer Agent may require a signature guarantee. Notarization by a notary public is not an acceptable signature guarantee. The Transfer Agent reserves the right to reject a signature guarantee and to request additional documentation for any transaction.

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Buying, Selling and Exchanging Shares (continued)

Customer Identification Program

Federal law requires the Fund to obtain and record specific personal information to verify your identity when you open an account. This information may include your name, address, date of birth (for individuals) and taxpayer or other government issued identification (e.g., social security number (SSN) or other taxpayer identification number (TIN)). If you fail to provide the requested information, the Fund may need to delay the date of your purchase or may be unable to open your account, which may result in a return of your investment monies. In addition, if the Fund is unable to verify your identity after your account is open, the Fund reserves the right to close your account or take other steps as deemed reasonable. The Fund will not be liable for any loss resulting from any purchase delay, application rejection or account closure due to a failure to provide proper identifying information.

Small Account Policy — Class A, Class C, and Class Inst Share Accounts Below the Minimum Account Balance

The Funds generally will automatically sell your shares if the value of your Fund account (treating each account of the Fund you own separately from any other account of the Fund you may own) falls below the applicable minimum account balance. Any otherwise applicable CDSC will not be imposed on such an automatic sale of your shares. Generally, you may avoid such an automatic sale by raising your account balance to at least $250 or consolidating your multiple accounts you may have with the Funds through an exchange (so as to maintain at least $250 in each of your accounts). The minimum account balance varies among share classes and types of accounts, as follows:

Minimum Account Balance
	Minimum Account Balance
For all classes and account types except those listed below	$250 (None for accounts with Systematic Investment Plans)
Individual Retirement Accounts for all classes except those listed below	None
Class Adv, Class Inst2, Class Inst3 and Class R	None

For shares held directly with the Funds’ Transfer Agent, if your shares are sold, the Transfer Agent will remit the sale proceeds to you. The Transfer Agent will send you written notification in advance of any automatic sale, which will provide details on how you may avoid such an automatic sale. Generally, you may avoid such an automatic sale by raising your account balance to at least $250, consolidating your multiple accounts you may have with the Funds through an exchange (so as to maintain at least $250 in each of your accounts), or setting up a Systematic Investment Plan. For more information, contact the Transfer Agent or your financial intermediary. The Transfer Agent's contact information (toll-free number and mailing addresses) as well as the Funds’ website address can be found at the beginning of the section Choosing a Share Class.

For shares purchased and held for your benefit through a financial intermediary, the Funds may instruct the intermediary to automatically sell your Fund shares if the transaction can be operationally administered by the intermediary.

Small Account Policy — Class A, Class C, and Class Inst Share Accounts Minimum Balance Fee

If the value of your Fund account (treating each account of the Fund you own separately from any other account of the Fund you may own) falls below the minimum initial investment requirement applicable to you for any reason, including as a result of market decline, your account generally could be subject to a $20 annual fee. The Transfer Agent will reduce the expenses paid by the Fund by any amounts it collects from the assessment of this fee. For Funds that do not have transfer agency expenses against which to offset the amount collected through assessment of this fee, the fee will be paid directly to the Fund. The Funds reserve the right to lower the account size trigger point for the minimum balance fee in any year or for any class of shares when we believe it is appropriate to do so in light of declines in the market value of Fund shares or for other reasons.

For shares held directly with the Funds’ Transfer Agent, this fee will be assessed through the automatic sale of Fund shares in your account. Any otherwise applicable CDSC will not be imposed on such an automatic sale of your shares. The Transfer Agent will send you written notification in advance of assessing any fee, which will provide

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Buying, Selling and Exchanging Shares (continued)

details on how you can avoid the imposition of such fee. Generally, you may avoid the imposition of such fee by raising your Fund account balance, consolidating your multiple accounts you may have with the Funds, or setting up a Systematic Investment Plan that invests at least monthly. For more information, contact the Transfer Agent or your financial intermediary. The Transfer Agent's contact information (toll-free number and mailing addresses) as well as the Funds’ website address can be found at the beginning of the section Choosing a Share Class.

For shares purchased and held for your benefit through a financial intermediary, this fee could be assessed through the automatic sale of Fund shares in your account if instructed by the Fund and the transaction can be operationally administered by the intermediary.

Exceptions to the Small Account Policy (Accounts Below Minimum Account Balance) and Minimum Balance Fee

The automatic sale of Fund shares in accounts under $250 and the annual minimum balance fee described above do not apply to shareholders of Class Adv, Class Inst2, Class Inst3 and Class R shares; shareholders holding their shares through financial intermediary networked accounts; wrap fee and omnibus accounts; accounts with active monthly Systematic Investment Plans; certain qualified retirement plans; and health savings accounts. The automatic sale of Fund shares of accounts under the applicable minimum account balance does not apply to individual retirement plans.

Small Account Policy — Financial Intermediary Networked and Wrap Fee Accounts

The Funds may automatically redeem, at any time, financial intermediary networked accounts and wrap fee accounts that have account balances of $20 or less or have less than one share.

For shares purchased and held for your benefit through a financial intermediary, the Funds may instruct the intermediary to automatically sell your Fund shares if the transaction can be operationally administered by the intermediary.

Information Sharing Agreements

As required by Rule 22c-2 under the 1940 Act, the Funds or certain of their service providers will enter into information sharing agreements with financial intermediaries, including participating life insurance companies and financial intermediaries that sponsor or offer retirement plans through which shares of the Funds are made available for purchase. Pursuant to Rule 22c-2, financial intermediaries are required, upon request, to: (i) provide shareholder account and transaction information; and (ii) execute instructions from the Fund to restrict or prohibit further purchases of Fund shares by shareholders who have been identified by the Fund as having engaged in transactions that violate the Fund's excessive trading policies and procedures.

Excessive Trading Practices Policy

Right to Reject or Restrict Share Transaction Orders— The Fund is intended for investors with long-term investment purposes and is not intended as a vehicle for frequent trading activity (market timing) that is excessive. Investors should transact in Fund shares primarily for investment purposes. The Board has adopted excessive trading policies and procedures that are designed to deter excessive trading by investors (the Excessive Trading Policies and Procedures). The Fund discourages and does not accommodate excessive trading.

The Fund reserves the right to reject, without any prior notice, any purchase or exchange order for any reason, and will not be liable for any loss resulting from rejected orders. For example, the Fund may in its sole discretion restrict or reject a purchase or exchange order even if the transaction is not subject to the specific limitation described below if the Fund or its agents determine that accepting the order could interfere with efficient management of the Fund's portfolio or is otherwise contrary to the Fund's best interests. The Excessive Trading Policies and Procedures apply equally to purchase or exchange transactions communicated directly to the Transfer Agent and to those received by financial intermediaries.

Specific Buying and Exchanging Limitations — If the Fund detects that an investor has made two “material round trips” in any 28-day period, it will generally reject the investor's future purchase orders, including exchange purchase orders, involving any Fund.

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For these purposes, a “round trip” is a purchase or exchange into the Fund followed by a sale or exchange out of the Fund, or a sale or exchange out of the Fund followed by a purchase or exchange into the Fund. A “material” round trip is one that is deemed by the Fund to be material in terms of its amount or its potential detrimental impact on the Fund. Independent of this limit, the Fund may, in its sole discretion, reject future purchase orders by any person, group or account that appears to have engaged in any type of excessive trading activity.

These limits generally do not apply to automated transactions or transactions by registered investment companies in a “fund-of-funds” structure. These limits do not apply to payroll deduction contributions by retirement plan participants, transactions initiated by a retirement plan sponsor or certain other retirement plan transactions consisting of rollover transactions, loan repayments and disbursements, and required minimum distribution redemptions. They may be modified or rescinded for accounts held by certain retirement plans to conform to plan limits, for considerations relating to the Employee Retirement Income Security Act of 1974 or regulations of the Department of Labor, and for certain asset allocation or wrap programs. Accounts known to be under common ownership or control generally will be counted together, but accounts maintained or managed by a common intermediary generally will not be considered to be under common ownership or control. The Fund reserves the right to modify these restrictions at any time without prior notice to shareholders. In addition, the Fund may, in its sole discretion, reinstate trading privileges that have been revoked under the Fund's Excessive Trading Policies and Procedures.

Limitations on the Ability to Detect and Prevent Excessive Trading Practices — The Fund takes various steps designed to detect and prevent excessive trading, including daily review of available shareholder transaction information. However, the Fund receives buy, sell or exchange orders through financial intermediaries, and cannot always know of or reasonably detect excessive trading that may be facilitated by financial intermediaries or by the use of the omnibus account arrangements they offer. Omnibus account arrangements are common forms of holding shares of mutual funds, particularly among certain financial intermediaries such as broker-dealers, retirement plans and variable insurance products. These arrangements often permit financial intermediaries to aggregate their clients' transactions and accounts, and in these circumstances, the identities of the financial intermediary clients that beneficially own Fund shares are often not known to the Fund.

Some financial intermediaries apply their own restrictions or policies to their clients’ transactions and accounts, which may be more or less restrictive than those described here. This may impact the Fund's ability to curtail excessive trading, even where it is identified. For these and other reasons, it is possible that excessive trading may occur despite the Fund's efforts to detect and prevent it.

Although these restrictions and policies involve judgments that are inherently subjective and may involve some selectivity in their application, the Fund seeks to act in a manner that it believes is consistent with the best interests of Fund shareholders in making any such judgments.

Risks of Excessive Trading — Excessive trading creates certain risks to the Fund's long-term shareholders and may create the following adverse effects:

■ negative impact on the Fund's performance;

■ potential dilution of the value of the Fund's shares;

■ interference with the efficient management of the Fund's portfolio, such as the need to maintain undesirably large cash positions, the need to use its line of credit or the need to buy or sell securities it otherwise would not have bought or sold;

■ losses on the sale of investments resulting from the need to sell securities at less favorable prices;

■ increased taxable gains to the Fund's remaining shareholders resulting from the need to sell securities to meet sell orders; and

■ increased brokerage and administrative costs.

To the extent that the Fund invests significantly in foreign securities traded on markets that close before the Fund's valuation time, it may be particularly susceptible to dilution as a result of excessive trading. Because events may occur after the close of foreign markets and before the Fund's valuation time that influence the value of foreign

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securities, investors may seek to trade Fund shares in an effort to benefit from their understanding of the value of foreign securities as of the Fund's valuation time. This is often referred to as price arbitrage. The Fund has adopted procedures designed to adjust closing market prices of foreign securities under certain circumstances to reflect what the Fund believes to be the fair value of those securities as of its valuation time. To the extent the adjustments do not work fully, investors engaging in price arbitrage may cause dilution in the value of the Fund's shares held by other shareholders.

The Columbia Acorn Funds may invest in thinly traded equity securities of small-capitalization companies. Because

these securities are often traded infrequently, investors may seek to trade Fund shares in an effort to benefit from their understanding of the value of these securities as of the Fund's valuation time. This is also a type of price arbitrage. Any such frequent trading strategies may interfere with efficient management of the Fund's portfolio to a greater degree than would be the case for mutual funds that invest only, or significantly, in highly liquid securities, in part because the Fund may have difficulty selling these particular investments at advantageous times or prices to satisfy large and/or frequent sell orders. Any successful price arbitrage may also cause dilution in the value of Fund shares held by non-redeeming shareholders.

Opening an Account and Placing Orders

We encourage you to consult with a financial advisor who can help you with your investment decisions and who can help you open an account. Once you have an account, you can buy, sell or exchange shares by contacting your financial advisor who will send your order to the Transfer Agent or your financial intermediary. As described below, once you have an account you can also communicate your orders directly to the Transfer Agent by mail, by telephone or online.

The Funds are generally available directly and through broker-dealers, banks and other financial intermediaries or institutions, and through certain qualified and non-qualified plans, wrap fee products or other investment products sponsored by financial intermediaries. You may buy, sell, or exchange shares through your financial intermediary. If you maintain your account directly with your financial intermediary, you must contact that agent to process your transaction.

Not all financial intermediaries offer the Funds (or all classes of Fund shares) and certain financial intermediaries that offer the Funds may not offer all Funds on all investment platforms or programs. Please consult with your financial intermediary to determine the availability of the Funds. If you set up an account at a financial intermediary that does not have, and is unable to obtain, a selling agreement with the Distributor, you will not be able to transfer Fund holdings to that account. In that event, you must either maintain your Fund holdings with your current financial intermediary or find another financial intermediary with a selling agreement.

Financial intermediaries that offer the Funds may charge you additional fees for the services they provide and they may have different policies that are not described in this prospectus. An investor transacting in a class of Fund shares without any front-end sales charge, CDSC, or other asset-based fee for sales or distribution, such as a Rule 12b-1 fee, may be required to pay a commission to the financial intermediary for effecting such transactions. The Funds are offered in a number of different share classes that have different fees and expenses and other features. Some differences in the policies of different financial intermediaries may include different minimum investment amounts, exchange privileges, Fund/class choices and cutoff times for investments. Additionally, recordkeeping, transaction processing and payments of distributions relating to your account may be performed by the financial intermediaries through which your shares of the Fund are held. Since the Fund (and its service providers) may not have a record of your account transactions, you should always contact the financial intermediary through which you purchased or at which you maintain your shares of the Fund to make changes to your account, to give instructions concerning your account, or to obtain information about your account. The Fund and its service providers, including the Distributor and the Transfer Agent, are not responsible for the failure of any financial intermediary to carry out its obligations to its customers.

The Fund may engage financial intermediaries to receive purchase, exchange and sell orders on its behalf. Accounts established directly with the Fund will be serviced by the Transfer Agent. The Funds, the Transfer Agent and the Distributor do not provide investment advice.

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Direct-At-Fund Accounts (Accounts Held Directly with the Fund)

Fund shares can be held in a variety of ways. You can hold Fund shares through an account established and held through the financial intermediary through which you purchased Fund shares, or you or your financial intermediary can establish an account directly with the Fund, in which case you will receive Fund account transaction confirmations and statements from the Transfer Agent, and not your financial intermediary (Direct-at-Fund Accounts). Direct-at-Fund Accounts include accounts held at the Transfer Agent that do not or no longer have a financial intermediary assigned to them.

To open a Direct-at-Fund Account, complete a Fund account application with your financial advisor or investment professional, and mail the account application to the Transfer Agent. Account applications may be obtained at columbiathreadneedleus.com or may be requested by calling 800.345.6611. Make your check payable to the Fund. You will be assessed a $15 fee for any checks rejected by your financial institution due to insufficient funds or other reasons. The Funds do not accept cash, credit card convenience checks, money orders, traveler's checks, starter checks, third or fourth party checks, or other cash equivalents.

Mail your check and completed application to the Transfer Agent at its regular or express mail address that can be found at the beginning of the section Choosing a Share Class. You may also use these addresses to request an exchange or redemption of Fund shares. When a written order to buy, sell or exchange shares is sent to the Transfer Agent, the share price used to fill the order is the next price calculated by the Fund after the Transfer Agent receives your transaction request in “good form” at its transaction processing center (i.e., the Fund’s express mail address), not the P.O. Box provided for regular mail delivery.

You will be sent a statement confirming your purchase and any subsequent transactions in your account. You will also be sent quarterly and annual statements detailing your transactions in the Fund and the other Funds you own under the same account. Duplicate quarterly account statements for the current year and duplicate annual statements for the most recent prior calendar year will be sent to you free of charge. Copies of year-end statements for prior years are available for a fee. Please contact the Transfer Agent for more information.

Written Transactions – Direct-at-Fund Accounts

If you have a Direct-at-Fund Account, you can communicate written buy, sell or exchange orders to the Transfer Agent at its address that can be found at the beginning of the section Choosing a Share Class. When a written order to buy, sell or exchange shares is sent to the Transfer Agent, the share price used to fill the order is the next price calculated by the Fund after the Transfer Agent receives your transaction request in “good form” at its transaction processing center (i.e., the Fund’s express mail address), not the P.O. Box provided for regular mail delivery.

Include in your transaction request letter: your name; the name of the Fund(s); your account number; the class of shares to be purchased, exchanged or sold; your SSN or other TIN; the dollar amount or number of shares you want to purchase, exchange or sell; specific instructions regarding delivery of any redemption proceeds or exchange destination (i.e., the Fund/class to be exchanged into); signature(s) of all registered account owner(s); and any special documents the Transfer Agent may require in order to process your order.

Corporate, trust or partnership accounts may need to send additional documents. Payment will be mailed to the address of record and made payable to the names listed on the account, unless your request specifies differently and is signed by all owners.

Telephone Transactions – Direct-at-Fund Accounts

For Class A, Class C, Class Inst, Class Inst3 and Class R shares, if you have a Direct-at-Fund Account, you may place orders to buy, sell or exchange shares by telephone through the Transfer Agent. To place orders by telephone, call 800.422.3737. Have your account number and SSN or TIN available when calling.

You can sell Fund shares via telephone and receive redemption proceeds: by electronic funds transfer via ACH, by wire, or by check to the address of record, subject to a maximum of $100,000 of shares per day, per Fund account. You can buy Fund shares via telephone by electronic funds transfer via ACH from your bank account up to a maximum

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of $100,000 of shares per day, per Fund account, or by wire from your bank account without a maximum. See below for more information regarding wire and electronic fund transfer transactions. Certain restrictions apply, so please call the Transfer Agent at 800.422.3737 for this and other information in advance of any need to transact via telephone.

Telephone orders may not be as secure as written orders. The Fund will take reasonable steps to confirm that telephone instructions are genuine. For example, we require proof of your identification before we will act on instructions received by telephone and may record telephone conversations. However, the Fund and its agents will not be responsible for any losses, costs or expenses resulting from an unauthorized telephone instruction when reasonable steps have been taken to confirm that telephone instructions are genuine. Telephone orders may be difficult to complete during periods of significant economic or market change or business interruption.

Online Transactions – Direct-at-Fund Accounts

For Class A, Class C, Class Inst, Class Inst3 and Class R shares, if you have a Direct-at-Fund Account, you may be able to place orders to buy, sell, or exchange shares online. Contact the Transfer Agent at 800.345.6611 for more information on certain account trading restrictions and the special sign-up procedures required for online transactions. You can also go to columbiathreadneedleus.com/investor/ to sign up for online transactions. The Transfer Agent has procedures in place to authenticate electronic orders you send through the internet. You will be required to accept the terms of an online agreement and to establish an online account and utilize a password in order to access online account services. You can sell a maximum of $100,000 of shares per day, per Fund account through your online account if you qualify for internet orders. Wire transactions are not permitted online.

Wire Transactions – Direct-at-Fund Accounts

If you hold a Direct-at-Fund Account, you may purchase or redeem Class A, Class C, Class Inst, Class Inst3 and Class R shares of a Fund by wiring money from (or to) your bank account to (or from) your Fund account. You must set up this feature prior to your request unless you are submitting your request in writing, which may require a Medallion Signature Guarantee. Please contact the Transfer Agent by calling 800.422.3737 to obtain the necessary forms and requirements. The Transfer Agent charges a fee for shares sold by wire. The Transfer Agent may waive the fee for certain accounts. In the case of a redemption, the receiving bank may charge an additional fee. The minimum amount that can be redeemed by wire is $500. When selling Fund shares via a telephone request, the maximum amount that can be redeemed via wire transfer is $100,000 per day, per Fund account. Wire transactions are not permitted online.

Electronic Funds Transfer via ACH – Direct-at-Fund Accounts

If you hold a Direct-at-Fund Account, you may purchase or redeem Class A, Class C, Class Inst, Class Inst3 and Class R shares of a Fund by electronically transferring money via Automated Clearing House (ACH) from (or to) your bank account to (or from) your Fund account subject to a maximum of $100,000 of shares per day, per Fund account. You must set up this feature prior to your request, unless you are submitting your request in writing, which may require a Medallion Signature Guarantee. Please contact the Transfer Agent by calling 800.422.3737 to obtain the necessary forms and requirements. Your bank may take up to three business days to post an electronic funds transfer to (or from) your Fund account.

Buying Shares

Eligible Investors

Class A Shares

Class A shares are available to the general public for investment.

Class Adv Shares

Class Adv shares are available only to (i) omnibus retirement plans, including self-directed brokerage accounts within omnibus retirement plans that clear through institutional no transaction fee (NTF) platforms, (ii) trust companies or similar institutions, (iii) broker-dealers, banks, trust companies and similar institutions that clear Fund share

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transactions for their client or customer investment advisory or similar accounts through designated financial intermediaries and their mutual fund trading platforms that have been granted specific written authorization from the Transfer Agent with respect to Class Adv eligibility apart from selling, servicing or similar agreements, (iv) 501(c)(3) charitable organizations, (v) 529 plans, (vi) health savings accounts, (vii) investors participating in a fee-based advisory program sponsored by a financial intermediary or other entity that is not compensated by the Fund for those services, other than payments for shareholder servicing or sub-accounting performed in place of the Transfer Agent, and (viii) commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Adv shares within such platform.

Class C Shares

Class C shares are available to the general public for investment, except that Direct-at-Fund Accounts that do not have a financial intermediary assigned to them are not permitted to purchase Class C shares; Class C share purchase orders received on or after such date from Direct-at-Fund Accounts that do not have a financial intermediary assigned to the account will automatically be invested in Class A shares of the same Fund.

Class Inst Shares

Class Inst shares are available only to the categories of eligible investors described below under Class Inst Shares Minimum Initial Investments. Financial intermediaries that clear Fund share transactions through designated financial intermediaries and their mutual fund trading platforms that were given specific written notice from the Transfer Agent of the termination, effective March 29, 2013, of their eligibility for new purchases of Class Inst shares and omnibus retirement plans are not permitted to establish new Class Inst accounts, subject to certain exceptions described below.

Omnibus retirement plans that opened and, subject to certain exceptions, funded a Class Inst account with the Fund as of the close of business on March 28, 2013 and have continuously held Class Inst shares in such account after such date (each, a grandfathered plan), may generally continue to make additional purchases of Class Inst shares, open new Class Inst accounts and add new participants. In addition, an omnibus retirement plan affiliated with a grandfathered plan may, in the sole discretion of the Distributor, open new Class Inst accounts in a Fund if the affiliated plan opened a Class Inst account on or before March 28, 2013. If an omnibus retirement plan invested in Class Inst shares changes recordkeepers after March 28, 2013, any new accounts established for that plan may not be established in Class Inst shares, but such a plan may establish new accounts in a different share class for which the plan is eligible.

Accounts of financial intermediaries (other than omnibus retirement plans, which are discussed above) that clear Fund share transactions for their client or customer accounts through designated financial intermediaries and their mutual fund trading platforms that received specific written notice from the Transfer Agent of the termination, effective March 29, 2013, of their eligibility for new purchases of Class Inst shares will not be permitted to establish new Class Inst accounts or make additional purchases of Class Inst shares (other than through reinvestment of distributions). Any such account may, at its holder’s option, exchange Class Inst shares of a Fund, without the payment of a sales charge, for Class A shares of the same Fund.

Class Inst2 Shares

Class Inst2 shares are available only to (i) certain registered investment advisers and family offices that clear Fund share transactions for their client or customer accounts through designated financial intermediaries and their mutual fund trading platforms that have been granted specific written authorization from the Transfer Agent with respect to Class Inst2 eligibility apart from selling, servicing or similar agreements; (ii) omnibus retirement plans; (iii) health savings accounts, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst2 shares within such platform and that Fund shares are held in an omnibus account; and (iv) institutional investors that are clients of the Columbia Threadneedle Global Institutional Distribution Team that invest in Class Inst2 shares for their own account through platforms approved by the Distributor or an affiliate thereof to offer and/or service Class Inst2 shares within such platform. Prior to November 8, 2012, Class Inst2

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shares were closed to new investors and new accounts, subject to certain exceptions. Existing shareholders who do not satisfy the new eligibility requirements for investment in Class Inst2 may not establish new Class Inst2 accounts but may continue to make additional purchases of Class Inst2 shares in accounts opened and funded prior to November 8, 2012; provided, however, that investment advisory programs and similar programs that opened a Class Inst2 account as of May 1, 2010, and continuously hold Class Inst2 shares in such account after such date, may generally not only continue to make additional purchases of Class Inst2 shares but also open new Class Inst2 accounts for such pre-existing programs and add new shareholders in the program.

Class Inst3 Shares

Class Inst3 shares are available to: (i) group retirement plans that maintain plan-level or omnibus accounts with the Fund (through the Transfer Agent); (ii) institutional investors that are clients of the Columbia Threadneedle Global Institutional Distribution Team that invest in Class Inst3 shares for their own account through platforms approved by the Distributor or an affiliate thereof to offer and/or service Class Inst3 shares within such platform; (iii) collective trust funds; (iv) affiliated or unaffiliated mutual funds (e.g., funds operating as funds-of-funds); (v) fee-based platforms of financial intermediaries (or the clearing intermediary that they trade through) that have an agreement with the Distributor or an affiliate thereof that specifically authorizes the financial intermediary to offer and/or service Class Inst3 shares within such platform, provided also that Fund shares are held in an omnibus account; (vi) commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst3 shares within such platform and that Fund shares are held in an omnibus account; (vii) health savings accounts, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst3 shares within such platform and that Fund shares are held in an omnibus account; and (viii) bank trust departments, subject to an agreement with the Distributor that specifically authorizes offering Class Inst3 shares and provided that Fund shares are held in an omnibus account. In each case above where noted that Fund shares are required to be held in an omnibus account, the Distributor may, in its discretion, determine to waive this requirement.

Class R Shares

Class R shares are available only to eligible health savings accounts sponsored by third party platforms, including those sponsored by Ameriprise Financial affiliates, eligible retirement plans and, in the sole discretion of the Distributor, other types of retirement accounts held through platforms maintained by financial intermediaries approved by the Distributor. Eligible retirement plans include any retirement plan other than individual 403(b) plans. Class R shares are generally not available for investment through retail nonretirement accounts, traditional and Roth IRAs, Coverdell Education Savings Accounts, SEPs, SAR-SEPs, Simple IRAs or 529 tuition programs. Contact the Transfer Agent or your retirement plan or health savings account administrator for more information about investing in Class R shares.

Additional Eligible Investors

In addition, the Distributor, in its sole discretion, may accept investments in any share class from investors other than those listed in this prospectus, and may also waive certain eligibility requirements for operational and other reasons, including but not limited to any requirement to maintain Fund shares in networked or omnibus accounts.

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Minimum Initial Investments

The table below shows the Fund’s minimum initial investment requirements, which may vary by class and type of account.

The Fund reserves the right to redeem your shares if your account falls below the Fund’s minimum initial investment requirement.

Minimum Initial Investments
	Minimum Initial Investment(a)	Minimum Initial Investment for Accounts with Systematic Investment Plans
For all classes and account types except those listed below	$2,000	$100
Individual Retirement Accounts for all classes except those listed below	$1,000	$100
Group retirement plans	None	N/A
Class Adv and Class Inst	$0, $1,000 or $2,000(b)	$100(b)
Class Inst2 and Class R	None	N/A
Class Inst3	$0, $1,000, $2,000 or $1 million(c)	$100(c)

(a) If your Class A, Class Adv, Class C, Class Inst, or Class Inst3 shares account balance falls below the minimum initial investment amount for any reason, including a market decline, you may be asked to increase it to the minimum initial investment amount or establish a monthly Systematic Investment Plan. If you do not do so, your account will be subject to a $20 annual low balance fee and/or shares may be automatically redeemed and the proceeds mailed to you if the account falls below the minimum account balance. See Buying, Selling and Exchanging Shares — Transaction Rules and Policies above. There is no minimum initial investment in Class A shares for accounts held in an omnibus account on a mutual fund only platform offered through your financial intermediary.

(b) The minimum initial investment in Class Adv shares is $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts) for commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customers, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Adv shares within such platform; for all other eligible Class Adv share investors (see Buying Shares – Eligible Investors – Class Adv Shares above), there is no minimum initial investment. The minimum initial investment amount for Class Inst shares is $0, $1,000 or $2,000 depending upon the category of eligible investor. See — Class Inst Shares Minimum Initial Investments below. The minimum initial investment amount for Systematic Investment Plan accounts is the same as the amount set forth in the first two rows of the table, as applicable.

(c) There is no minimum initial investment in Class Inst3 shares for: group retirement plans that maintain plan-level or omnibus accounts with the Fund; collective trust funds; affiliated or unaffiliated mutual funds (e.g., funds operating as funds-of-funds); and fee -based platforms of financial intermediaries (or the clearing intermediary that they trade through) that have an agreement with the Distributor or an affiliate thereof that specifically authorizes the financial intermediary to offer and/or service Class Inst3 shares within such platform and Fund shares are held in an omnibus account. The minimum initial investment in Class Inst3 shares is $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts) for commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst3 shares within such platform and Fund shares are held in an omnibus account. The minimum initial investment in Class Inst3 shares is $1 million, unless waived in the discretion of the Distributor, for the following investors: institutional investors that are clients of the Columbia Threadneedle Global Institutional Distribution Team that invest in Class Inst3 shares for their own account through platforms approved by the Distributor or an affiliate thereof to offer and/or service Class Inst3 shares within such platform; and bank trust departments, subject to an agreement with the Distributor that specifically authorizes offering Class Inst3 shares and provided that Fund shares are held in an omnibus account. The Distributor may, in its discretion, waive the $1 million minimum initial investment required for these Class Inst3 investors. In each case above where noted that Fund shares are required to be held in an omnibus account, the Distributor, may, in its discretion, determine to waive this requirement.

Additional Information about Minimum Initial Investments

The minimum initial investment requirements may be waived for accounts that are managed by an investment professional, or for accounts held in approved discretionary or non-discretionary wrap programs. The Distributor, in its sole discretion, may also waive minimum initial investment requirements for other account types.

Minimum investment and related requirements may be modified at any time, with or without prior notice. If your account is closed and then re-opened with a Systematic Investment Plan, your account must meet the then-current applicable minimum initial investment.

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Class Inst Shares Minimum Initial Investments

There is no minimum initial investment in Class Inst shares for the following categories of eligible investors:

■ Any health savings account sponsored by a third party platform.

■ Any investor participating in an account sponsored by a financial intermediary or other entity (that provides services to the account) that is paid a fee-based advisory fee by the investor and that is not compensated by the Fund for those services, other than payments for shareholder servicing or sub-accounting performed in place of the Transfer Agent.

■ Any commissionable brokerage account, if a financial intermediary has received a written approval from the Distributor to waive the minimum initial investment in Class Inst shares.

■ Any Trustee (or family member) of Columbia Acorn Trust.

■ Any employee (or family member) of the Investment Manager.

The minimum initial investment in Class Inst shares for the following categories of eligible investors is $1,000:

■ Individual retirement accounts (IRAs) on commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst shares within such platform.

■ Any current employee of Columbia Management Investment Advisers LLC, the Distributor or the Transfer Agent and immediate family members of any of the foregoing who share the same address are eligible to invest in Class Inst shares through an individual retirement account (IRA). If you maintain your account with a financial intermediary, you must contact that financial intermediary each time you seek to purchase shares to notify them that you qualify for Class Inst shares. If Class Inst shares are not available at your financial intermediary, you may consider opening a Direct-at-Fund Account. It is your obligation to advise your financial intermediary or (in the case of Direct-at-Fund Accounts) the Transfer Agent that you qualify for Class Inst shares; be prepared to provide proof thereof.

The minimum initial investment in Class Inst shares for the following categories of eligible investors is $2,000:

■ Investors (except investors in individual retirement accounts (IRAs)) who purchase Fund shares through commissionable brokerage platforms where the financial intermediary holds the shares in an omnibus account and, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst shares within such platform.

■ Any current employee of Columbia Management Investment Advisers LLC, the Distributor or the Transfer Agent and immediate family members of any of the foregoing who share the same address are eligible to invest in Class Inst shares (other than individual retirement accounts (IRAs), for which the minimum initial investment is $1,000). If you maintain your account with a financial intermediary, you must contact that financial intermediary each time you seek to purchase shares to notify them that you qualify for Class Inst shares. If Class Inst shares are not available at your financial intermediary, you may consider opening a Direct-at-Fund Account. It is your obligation to advise your financial intermediary or (in the case of Direct-at-Fund Accounts) the Transfer Agent that you qualify for Class Inst shares; be prepared to provide proof thereof.

■ Certain financial institutions and intermediaries, such as insurance companies, trust companies, banks, endowments, investment companies or foundations, buying shares for their own account, including Ameriprise Financial and its affiliates and/or subsidiaries.

■ Bank trust departments that assess their clients an asset-based fee.

■ Any trustee or director (or family member of a trustee or director) of a fund distributed by the Distributor (other than the Columbia Acorn Funds).

■ Certain other investors as set forth in more detail in the SAI.

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Buying, Selling and Exchanging Shares (continued)

Systematic Investment Plan

The Systematic Investment Plan allows you to schedule regular purchases via automatic transfers from your bank account to the Fund on a monthly, quarterly or semiannual basis. Contact the Transfer Agent or your financial intermediary to set up the plan. Systematic Investment Plans may not be available for all share classes. With the exception of Columbia Government Money Market Fund, Systematic Investment Plan purchases will be confirmed on your quarterly account statement. Columbia Government Money Market Fund Systematic Investment Plan purchases will be confirmed at the time of the purchase. If establishing a Systematic Investment Plan to reduce the initial fund minimum, the plan needs to be established monthly to avoid the small account fee.

Dividend Diversification

Generally, you may automatically invest Fund distributions into the same class of shares (and in some cases certain other classes of shares) of another Fund without paying any applicable front-end sales charge. Call the Transfer Agent at 800.345.6611 for details. The ability to invest distributions from one Fund to another Fund may not be available to accounts held at all financial intermediaries.

Other Purchase Rules You Should Know

■ Once the Transfer Agent or your financial intermediary receives your purchase order in “good form,” your purchase will be made at the Fund’s next calculated public offering price per share, which is the NAV per share plus any sales charge that applies (i.e., the trade date).

■ Once the Fund receives your purchase request in “good form,” you cannot cancel it after the market closes.

■ You generally buy Class A shares at the public offering price per share because purchases of these share classes are generally subject to a front-end sales charge.

■ You buy Class Adv, Class C, Class Inst, Class Inst2, Class Inst3 and Class R shares at NAV per share because no front-end sales charge applies to purchases of these share classes.

■ The Distributor and the Transfer Agent reserve the right to cancel your order request if the Fund does not receive payment within two business days of receiving your purchase order request. The Fund will return any payment received for orders that have been cancelled, but no interest will be paid on that money.

■ Financial intermediaries are responsible for sending your purchase orders to the Transfer Agent and ensuring that the Fund receives your money on time.

■ Shares purchased are recorded on the books of the Fund. The Fund does not issue certificates.

■ You generally may make a purchase only into a Fund that is accepting investments.

Please also read Appendix A and contact your financial intermediary for more information regarding any reductions and/or waivers described therein.

Selling Shares

When you sell shares, the amount you receive may be more or less than the amount you invested. Your sale price will be the next NAV calculated after your request is received in “good form,” (i.e., the trade date) minus any applicable CDSC.

Systematic Withdrawal Plan

The Systematic Withdrawal Plan allows you to schedule regular redemptions from your account any business day on a monthly, quarterly or semiannual basis. Currently, Systematic Withdrawal Plans are generally available for Class A, Class Adv, Class C, Class Inst, Class Inst2, and Class Inst3 share accounts. Contact the Transfer Agent or your financial intermediary to set up the plan. To set up the plan, your account balance must meet the class minimum initial investment amount. A Systematic Withdrawal Plan cannot be set up on an account that already has a Systematic Investment Plan established. Note that a Medallion Signature Guarantee may be required if this service is established after your Fund account is opened.

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Buying, Selling and Exchanging Shares (continued)

You can choose to receive your withdrawals via check or direct deposit into your bank account. The Fund will deduct any applicable CDSC from the withdrawals before sending redemption proceeds to you. You can cancel the plan by giving the Fund 30 days’ notice in writing or by calling the Transfer Agent at 800.422.3737. It’s important to remember that if you withdraw more than your investment in the Fund is earning, you'll eventually withdraw your entire investment.

Satisfying Fund Redemption Requests

When you sell your Fund shares, the Fund is effectively buying them back from you. This is called a redemption. Except as noted below with respect to newly purchased shares, the Fund typically expects to send you payment for your shares within two business days after your trade date. The Fund can suspend redemptions and/or delay payment of redemption proceeds for up to seven days. The Fund can also suspend redemptions and/or delay payment of redemption proceeds in excess of seven days under certain circumstances, including when the NYSE is closed or trading thereon is restricted or during emergency or other circumstances, including as determined by the SEC.

The Fund typically seeks to satisfy redemption requests from cash or cash equivalents held by the Fund, from the proceeds of orders to purchase Fund shares or from the proceeds of sales of Fund holdings effected in the normal course of managing the Fund. However, the Fund may have to sell Fund holdings, including in down markets, to meet heavier than usual redemption requests. For example, under stressed or abnormal market conditions or circumstances, including circumstances adversely affecting the liquidity of the Fund’s investments, the Fund may be more likely to be forced to sell Fund holdings to meet redemptions than under normal market circumstances. In these situations, the Fund’s portfolio managers may have to sell Fund holdings that would not otherwise be sold because, among other reasons, the current price to be received is less than the value of the holdings perceived by the Fund’s portfolio managers. The Fund may also, under certain circumstances (likely under stressed or abnormal market conditions or circumstances), borrow money under a credit facility to which the Fund and certain other Columbia Funds are parties. The Fund and the other Columbia Funds are limited as to the amount that each may individually and collectively borrow under the credit facility. As a result, borrowings available to the Fund under the credit facility might be insufficient, alone or in combination with the other strategies described herein, to satisfy Fund redemption requests. Please see About Fund Investments – Borrowings in the SAI for more information about the credit facility. The Fund is also limited in the total amount it may borrow. Please see About Fund Investments – Fundamental and Non-Fundamental Investment Policies in the SAI for more information about borrowing.

In addition, the Fund reserves the right to honor redemption orders in whole or in part with in-kind distributions of Fund portfolio securities instead of cash. Such in-kind distributions typically represent a pro-rata portion of Fund portfolio assets subject to adjustments (e.g., for non-transferable securities, round lots, and derivatives, if any). In the event the Fund distributes portfolio securities in kind, you may incur brokerage and other transaction costs associated with converting the portfolio securities you receive into cash. Also, the portfolio securities you receive may increase or decrease in value after they are distributed but before you convert them into cash. For U.S. federal income tax purposes, redemptions paid in securities are generally treated the same as redemptions paid in cash. The Trust has elected to be governed by Rule 18f-1 under the 1940 Act, which means that for each redeeming shareholder, the first $250,000, or 1% of the Fund's net asset value, whichever is less, will be paid in cash or cash equivalents and the remainder may be paid in kind.

While the Fund is not required (and may refuse in its discretion) to pay a redemption with an in-kind distribution of Fund portfolio securities and reserves the right to pay the redemption proceeds in cash, if you wish to request an in-kind redemption, please call the Transfer Agent at 800.345.6611. As a result of the operational steps needed to coordinate with the redeeming shareholder’s custodian, in-kind redemptions typically take several weeks to complete after a redemption request is received. The Fund and the redeeming shareholder will typically agree upon a redemption date. Since the Fund’s NAV may fluctuate during this time, the Fund’s NAV may be lower on the agreed-upon redemption date than on an earlier date on which the investment could have been redeemed for cash.

Prospectus 2022 57

Columbia Acorn International Select^SM

Buying, Selling and Exchanging Shares (continued)

Redemption of Newly Purchased Shares

You may not redeem shares for which the Fund has not yet received payment. Shares purchased by check or electronically by ACH when the purchase payment is not guaranteed will be considered in “good form” for redemption only after they have been held in your account for 6 calendar days after the trade date of the purchase (Collected Shares). If you request a redemption for an amount that, based on the NAV next calculated after your redemption request is received, includes any shares that are not yet Collected Shares, the Fund will only process the redemption up to the amount of the value of Collected Shares available in your account. You must submit a new redemption request if you wish to redeem those shares that were not yet Collected Shares at the time the original redemption request was received by the Fund.

Other Redemption Rules You Should Know

■ Once the Transfer Agent or your financial intermediary receives your redemption order in “good form,” your shares will be sold at the Fund’s next calculated NAV per share (i.e., the trade date). Any applicable CDSC will be deducted from the amount you're selling and the balance will be remitted to you.

■ Once the Fund receives your redemption request in “good form,” you cannot cancel it after the market closes.

■ The Distributor, in its sole discretion, reserves the right to liquidate Fund shares (of any class of the Fund) held in an omnibus account of a financial intermediary that clears Fund share transactions through a clearing intermediary or platform that charges certain maintenance fees to the Fund if the value of the omnibus account, at the Fund share class (i.e., CUSIP) level, falls below $100,000 (a CUSIP Liquidation Event). The Distributor will provide at least 90 days’ notice of a CUSIP Liquidation Event to financial intermediaries with impacted omnibus accounts. Shareholders invested in the Fund through such omnibus accounts can request through their financial intermediary a tax-free exchange to Class A shares or shareholders can consider holding their Fund shares in a Direct-at-Fund Account, provided requirements to transfer the account are fulfilled. You should discuss your options with your financial intermediary.

■ If you sell your shares that are held in a Direct-at-Fund Account, we will normally send the redemption proceeds by mail or electronically transfer them to your bank account the next business day after the trade date. Note that your bank may take up to three business days to post an electronic funds transfer from your account.

■ If you sell your shares through a financial intermediary, the Funds will normally send the redemption proceeds to your financial intermediary within two business days after the trade date.

■ No interest will be paid on uncashed redemption checks.

■ Other restrictions may apply to retirement accounts. For information about these restrictions, contact your retirement plan administrator.

■ For broker-dealer and wrap fee accounts: The Fund reserves the right to redeem your shares if your account falls below the Fund's minimum initial investment requirement. The Fund will notify your broker-dealer prior to redeeming shares, and will provide details on how to avoid such redemption.

■ Also keep in mind the Funds' Small Account Policy, which is described above in Buying, Selling and Exchanging Shares — Transaction Rules and Policies.

Exchanging Shares

You can generally sell shares of your Fund to buy shares of another Fund (subject to eligibility requirements), in what is called an exchange. You should read the prospectus of, and make sure you understand the investment objective, principal investment strategies, risks, fees and expenses of, the Fund into which you are exchanging. Although the Funds allow certain exchanges from one share class to another share class with higher expenses, you should consider the expenses of each class before making such an exchange. Please see Same-Fund Exchange Privilege below for more information.

You will be subject to a sales charge if, in a Direct-at-Fund Account, you exchange shares that have not previously paid a sales charge, including from Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia U.S.

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Buying, Selling and Exchanging Shares (continued)

Treasury Index Fund or any other Columbia Fund that does not charge a front-end sales charge, into a Columbia Fund that does assess a sales charge. If you hold your Fund shares through certain financial intermediaries, you may have limited exchangeability among the Funds. Please contact your financial intermediary for more information.

Systematic Exchanges

You may buy Class A, Class C, Class Inst and Class Inst3 shares of a Fund by exchanging each month from another Fund for shares of the same class of the Fund at no additional cost, subject to the following exchange amount minimums: $50 each month for individual retirement accounts (i.e., tax qualified accounts); and $100 each month for non-retirement accounts. Contact the Transfer Agent or your financial intermediary to set up the plan.

Exchanges will continue as long as your balance in the Fund you are exchanging shares from is sufficient to complete the systematic monthly exchange, subject to the Funds' Small Account Policy described above in Buying, Selling and Exchanging Shares — Transaction Rules and Policies. You may terminate the program or change the amount you would like to exchange (subject to the $50 and $100 minimum requirements noted immediately above) by calling the Transfer Agent at 800.345.6611.

Other Exchange Rules You Should Know

■ Exchanges are made at the NAV next calculated (plus any applicable sales charge) after your exchange order is received in “good form” (i.e., the trade date).

■ Once the Fund receives your exchange request in “good form,” you cannot cancel it after the market closes.

■ The rules for buying shares of a Fund generally apply to exchanges into that Fund, including, if your exchange creates a new Fund account, it must satisfy the minimum investment amount, unless a waiver applies.

■ Shares of the purchased Fund may not be used on the same day for another exchange or sale.

■ If you exchange shares from Class A shares of Columbia Government Money Market Fund to a non-money market Fund, any further exchanges must be between shares of the same class. For example, if you exchange from Class A shares of Columbia Government Money Market Fund into Class C shares of a non-money market Fund, you may not exchange from Class C shares of that non-money market Fund back to Class A shares of Columbia Government Money Market Fund or Class A shares of any other Fund.

■ A sales charge may apply when you exchange shares of a Fund that were not assessed a sales charge at the time you purchased such shares. If you invest through a Direct-at-Fund Account in Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund, Columbia U.S. Treasury Index Fund or any other Columbia Fund that does not impose a front-end sales charge and then you exchange into a Fund that does assess a sales charge, your transaction is subject to a front-end sales charge if you exchange into Class A shares and to a CDSC if you exchange into Class C shares of the Columbia Funds.

■ If you purchased Class A shares of a Columbia Fund that imposes a front-end sales charge (and you paid any applicable sales charge) and you then exchange those shares into Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund, Columbia U.S. Treasury Index Fund or any other Columbia Fund that does not impose a front-end sales charge, you may exchange that amount to Class A of another Fund in the future, including dividends earned on that amount, without paying a sales charge.

■ If your shares are subject to a CDSC, you will not be charged a CDSC upon the exchange of those shares. Any CDSC will be deducted when you sell the shares you received from the exchange. The CDSC imposed at that time will be based on the period that begins when you bought shares of the original Fund and ends when you sell the shares of the Fund you received from the exchange. Any applicable CDSC charged will be the CDSC of the original Fund.

■ You may make exchanges only into a Fund that is legally offered and sold in your state of residence. Contact the Transfer Agent or your financial intermediary for more information.

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Buying, Selling and Exchanging Shares (continued)

■ You generally may make an exchange only into a Fund that is accepting investments.

■ The Fund may change or cancel your right to make an exchange by giving the amount of notice required by regulatory authorities (generally 60 days for a material change or cancellation).

■ Unless your account is part of a tax-advantaged arrangement, an exchange for shares of another Fund is a taxable event, and you may recognize a gain or loss for tax purposes.

■ Changing your investment to a different Fund will be treated as a sale and purchase, and you will be subject to applicable taxes on the sale and sales charges on the purchase of the new Fund.

■ Class Inst shares of a Fund may be exchanged for Class A or Class Inst shares of another Fund. In certain circumstances, the front-end sales charge applicable to Class A shares may be waived on exchanges of Class Inst shares for Class A shares. See Buying, Selling and Exchanging Shares — Buying Shares — Eligible Investors — Class Inst Shares for details.

Same-Fund Exchange Privilege

Shareholders may be eligible to invest in other classes of shares of the same Fund, and may exchange their current shares for another share class if deemed eligible and offered by the Fund. Such same-Fund exchanges could include an exchange of one class for another with higher expenses. Before making such an exchange, you should consider the expenses of each class. Shareholders should contact their financial intermediaries to learn more about the details of the same-Fund exchange privilege. Exchanges out of Class A and Class C shares will be subject to any applicable CDSC. Financial intermediaries that have a customized arrangement with regard to CDSCs are detailed in Appendix A.

Exchanges out of Class C shares to another share class of the same Fund are not permissible on Direct-at-Fund Accounts, except that the Transfer Agent seeks to convert Class C shares as soon as administratively feasible to Class A shares of the same Fund for Direct-at-Fund Accounts that do not or no longer have a financial intermediary assigned to them. Direct-at-Fund Accounts that do not have a financial intermediary assigned to them are not permitted to purchase Class C shares. Class C share purchase orders received by Direct-at-Fund Accounts that do not have a financial intermediary assigned to the account will automatically be invested in Class A shares of the same Fund. Exchanges out of Class C shares to another share class of the same Fund within commissionable brokerage accounts are permitted only (1) when the shareholder moves from a commissionable brokerage account to a fee-based advisory program or (2) when the exchange is part of a share class conversion (or a similar multiple shareholder transaction event) instituted by a financial intermediary and such conversion or similar type event is preapproved by the Distributor.

Ordinarily, shareholders will not recognize a gain or loss for U.S. federal income tax purposes upon a same-Fund exchange. You should consult your tax advisor about your particular exchanges.

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Distributions and Taxes

Distributions to Shareholders

A mutual fund can make money two ways:

■ It can earn income on its investments. Examples of fund income are interest paid on money market instruments and bonds, and dividends paid on common stocks.

■ A mutual fund can also have capital gains if the value of its investments increases. While a fund continues to hold an investment, any gain is generally unrealized. If the fund sells an investment, it generally will realize a capital gain if it sells that investment for a higher price than its adjusted cost basis, and will generally realize a capital loss if it sells that investment for a lower price than its adjusted cost basis. Capital gains and losses are either short-term or long-term, depending on whether the fund holds the securities for one year or less (short-term) or more than one year (long-term).

Mutual funds make payments of fund earnings to shareholders, distributing them among all shareholders of the fund. As a shareholder, you are entitled to your portion of a fund's distributed income, including capital gains. Reinvesting your distributions buys you more shares of a fund — which lets you take advantage of the potential for compound growth. Putting the money you earn back into your investment means it, in turn, may earn even more money (or be exposed to additional losses, if the Fund earns a negative return). Over time, the power of compounding has the potential to significantly increase the value of your investment. There is no assurance, however, that you'll earn more money if you reinvest your distributions rather than receive them in cash.

The Fund intends to pay out, in the form of distributions to shareholders, a sufficient amount of its income and gains so that the Fund will qualify for treatment as a regulated investment company and generally will not have to pay any federal excise tax. The Fund generally intends to distribute any net realized capital gain (whether long-term or short-term gain) at least once a year. Normally, the Fund will declare and pay distributions of net investment income according to the following schedule:

Declaration and Distribution Schedule
Declarations	Semiannually
Distributions	Semiannually

The Fund may declare or pay distributions of net investment income more frequently.

Different share classes of the Fund usually pay different net investment income distribution amounts, because each class has different expenses. Each time a distribution is made, the NAV per share of the share class is reduced by the amount of the distribution.

The Fund generally pays cash distributions within five business days after the distribution was declared (or, if the Fund declares distributions daily, within five business days after the end of the month in which the distribution was declared). If you sell all of your shares after the record date, but before the payment date, for a distribution, you'll normally receive that distribution in cash within five business days after the sale was made.

The Fund will automatically reinvest distributions in additional shares of the same share class of the Fund unless you inform us you want to receive your distributions in cash (the financial intermediary through which you purchased shares may have different policies). You can do this by contacting the Funds at the addresses and telephone numbers listed at the beginning of the section entitled Choosing a Share Class. No sales charges apply to the purchase or sale of such shares.

For accounts held directly with the Fund (through the Transfer Agent), distributions of $10 or less will automatically be reinvested in additional Fund shares only. If you elect to receive distributions by check and the check is returned as undeliverable, all subsequent distributions will be reinvested in additional shares of the Fund.

Unless you are a tax-exempt investor or holding Fund shares through a tax-advantaged account (such as a 401(k) plan or IRA), you should consider avoiding buying Fund shares shortly before the Fund makes a distribution (other than distributions of net investment income that are declared daily) of net investment income or net realized capital gain, because doing so can cost you money in taxes to the extent the distribution consists of taxable income or gains. This is because you will, in effect, receive part of your purchase price back in the distribution. This is known as

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Columbia Acorn International Select^SM

Distributions and Taxes (continued)

“buying a dividend.” To avoid “buying a dividend,” before you invest check the Fund's distribution schedule, which is available at the Funds' website and/or by calling the Funds' telephone number listed at the beginning of the section entitled Choosing a Share Class.

Taxes

You should be aware of the following considerations applicable to the Fund:

■ The Fund intends to qualify and to be eligible for treatment each year as a regulated investment company. A regulated investment company generally is not subject to tax at the fund level on income and gains from investments that are distributed to shareholders. However, the Fund's failure to qualify for treatment as a regulated investment company would result in Fund-level taxation, and consequently, a reduction in income available for distribution to you and in the NAV of your shares. Even if the Fund qualifies for treatment as a regulated investment company, the Fund may be subject to federal excise tax on certain undistributed income or gains.

■ Otherwise taxable distributions generally are taxable to you when paid, whether they are paid in cash or automatically reinvested in additional Fund shares. Dividends paid in January are deemed paid on December 31 of the prior year if the dividend was declared and payable to shareholders of record in October, November, or December of such prior year.

■ Distributions of the Fund's ordinary income and net short-term capital gain, if any, generally are taxable to you as ordinary income. Distributions of the Fund's net long-term capital gain, if any, generally are taxable to you as long-term capital gain. Whether capital gains are long-term or short-term is determined by how long the Fund has owned the investments that generated them, rather than how long you have owned your shares. Certain events may require the Fund to sell significant amounts of appreciated securities, and make large capital gain dividends relative to the Fund’s NAV. Such events may include large net shareholder redemptions, portfolio re-balancing or fund mergers. The Fund generally provides estimates of expected capital gain dividends (if any) prior to the distribution on columbiathreadneedleus.com.

■ From time to time, a distribution from the Fund could constitute a return of capital. A return of capital is a return of an amount of your original investment and is not a distribution of income or capital gain from the Fund. Therefore, a return of capital is not taxable to you so long as the amount of the distribution does not exceed your tax basis in your Fund shares. A return of capital reduces your tax basis in your Fund shares, with any amounts exceeding such basis generally taxable as capital gain.

■ If you are an individual and you meet certain holding period and other requirements for your Fund shares, a portion of your distributions may be treated as “qualified dividend income” taxable at the lower net long-term capital gain rates instead of the higher ordinary income rates. Qualified dividend income is income attributable to the Fund's dividends received from certain U.S. and foreign corporations, as long as the Fund meets certain holding period and other requirements for the stock producing such dividends.

■ Certain high-income individuals (as well as estates and trusts) are subject to a 3.8% tax on net investment income. For individuals, the 3.8% tax applies to the lesser of (1) the amount (if any) by which the taxpayer's modified adjusted gross income exceeds certain threshold amounts or (2) the taxpayer's “net investment income.”

■ Certain derivative instruments when held in the Fund's portfolio subject the Fund to special tax rules, the effect of which may be to, among other things, accelerate income to the Fund, defer Fund losses, cause adjustments in the holding periods of Fund portfolio securities, or convert capital gains into ordinary income, short-term capital losses into long-term capital losses or long-term capital gains into short-term capital gains. These rules could therefore affect the amount, timing and/or character of distributions to shareholders.

■ Generally, a Fund realizes a capital gain or loss on an option when the option expires, or when it is exercised, sold or otherwise terminated. However, if an option is a “section 1256 contract,” which includes most traded options on a broad-based index, and the Fund holds such option at the end of its taxable year, the Fund is deemed to sell such option at fair market value at such time and recognize any gain or loss thereon, which is generally deemed to be 60% long-term and 40% short-term capital gain or loss, as described further in the SAI.

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Columbia Acorn International Select^SM

Distributions and Taxes (continued)

■ Income and proceeds received by the Fund from sources within foreign countries may be subject to foreign taxes. If at the end of the taxable year more than 50% of the value of the Fund's assets consists of securities of foreign corporations, and the Fund makes a special election, you will generally be required to include in your income for U.S. federal income tax purposes your share of the qualifying foreign income taxes paid by the Fund in respect of its foreign portfolio securities. You may be able to claim a foreign tax credit or deduction in respect of this amount, subject to certain limitations. There is no assurance that the Fund will make this election for a taxable year, even if it is eligible to do so.

■ A sale, redemption or exchange of Fund shares is a taxable event. This includes redemptions where you are paid in securities. Your sales, redemptions and exchanges of Fund shares (including those paid in securities) usually will result in a taxable capital gain or loss to you, equal to the difference between the amount you receive for your shares (or are deemed to have received in the case of exchanges) and your adjusted tax basis in the shares, which is generally the amount you paid (or are deemed to have paid in the case of exchanges) for them. Any such capital gain or loss generally will be long-term capital gain or loss if you have held your Fund shares for more than one year at the time of sale or exchange. In certain circumstances, capital losses may be converted from short-term to long-term; in other circumstances, capital losses may be disallowed under the “wash sale” rules.

■ For sales, redemptions and exchanges of shares that were acquired in a non-qualified account after 2011, the Fund generally is required to report to shareholders and the Internal Revenue Service (IRS) cost basis information with respect to those shares. The Fund uses average cost basis as its default method of calculating cost basis. For more information regarding average cost basis reporting, other available cost basis methods, and selecting or changing to a different cost basis method, please see the SAI, columbiathreadneedleus.com, or contact the Fund at 800.345.6611. If you hold Fund shares through a financial intermediary (e.g., a brokerage firm), you should contact your financial intermediary to learn about its cost basis reporting default method and the reporting elections available to your account.

■ The Fund is required by federal law to withhold tax on any taxable or tax-exempt distributions and redemption proceeds paid to you (including amounts paid to you in securities and amounts deemed to be paid to you upon an exchange of shares) if: you have not provided a correct TIN or have not certified to the Fund that withholding does not apply, the IRS has notified us that the TIN listed on your account is incorrect according to its records, or the IRS informs the Fund that you are otherwise subject to backup withholding.

 FUNDamentals

Taxes

The information provided above is only a summary of how U.S. federal income taxes may affect your investment in the Fund. It is not intended as a substitute for careful tax planning. Your investment in the Fund may have other tax implications. It does not apply to certain types of investors who may be subject to special rules, including foreign or tax-exempt investors or those holding Fund shares through a tax-advantaged account, such as a 401(k) plan or IRA. Please see the SAI for more detailed tax information. You should consult with your own tax advisor about the particular tax consequences to you of an investment in the Fund, including the effect of any foreign, state and local taxes, and the effect of possible changes in applicable tax laws.

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Columbia Acorn International Select^SM

Financial Highlights

The financial highlights table is intended to help you understand the Fund’s financial performance for the past five fiscal years. Certain information reflects financial results for a single Fund share. Per share net investment income (loss) amounts are calculated based on average shares outstanding during the period. The total return in the table represents the rate that an investor would have earned (or lost) on an investment in the Fund assuming all dividends and distributions had been reinvested. Total return does not reflect payment of sales charges, if any. Total return and portfolio turnover are not annualized for periods of less than one year. The portfolio turnover rate is calculated without regard to purchase and sales transactions of short-term instruments and certain derivatives, if any. If such transactions were included, the Fund’s portfolio turnover rate might be higher. The names of certain share classes may have changed during the periods shown below (see Appendix S to the SAI for details). This information has been audited by PricewaterhouseCoopers LLP, an independent registered public accounting firm, whose report, along with the Fund’s financial statements, is included in the Fund’s annual report, which is available upon request. The independent registered public accounting firm’s report and the Fund’s financial statements are also incorporated by reference into the SAI.

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Columbia Acorn International Select^SM

Financial Highlights (continued)

	Net asset value, beginning of period	Net investment income (loss)	Net realized and unrealized gain (loss)	Total from investment operations	Distributions from net investment income	Distributions from net realized gains	Total distributions to shareholders
Class A
Year Ended 12/31/2021	$33.67	(0.05)	3.50	3.45	(0.28)	(1.41)	(1.69)
Year Ended 12/31/2020	$28.58	(0.03)	5.21	5.18	(0.09)	—	(0.09)
Year Ended 12/31/2019	$23.44	0.09	7.67	7.76	(0.28)	(2.34)	(2.62)
Year Ended 12/31/2018	$28.89	0.06	(3.66)	(3.60)	—	(1.85)	(1.85)
Year Ended 12/31/2017	$21.36	0.02	7.52	7.54	(0.01)	—	(0.01)
Advisor Class
Year Ended 12/31/2021	$34.56	0.04	3.59	3.63	(0.43)	(1.41)	(1.84)
Year Ended 12/31/2020	$29.26	0.04	5.35	5.39	(0.09)	—	(0.09)
Year Ended 12/31/2019	$24.00	0.18	7.84	8.02	(0.42)	(2.34)	(2.76)
Year Ended 12/31/2018	$29.46	0.09	(3.70)	(3.61)	—	(1.85)	(1.85)
Year Ended 12/31/2017	$21.77	0.08	7.68	7.76	(0.07)	—	(0.07)
Class C
Year Ended 12/31/2021	$30.40	(0.30)	3.17	2.87	—	(1.41)	(1.41)
Year Ended 12/31/2020	$26.00	(0.23)	4.72	4.49	(0.09)	—	(0.09)
Year Ended 12/31/2019	$21.48	(0.10)	6.99	6.89	(0.03)	(2.34)	(2.37)
Year Ended 12/31/2018	$26.85	(0.12)	(3.40)	(3.52)	—	(1.85)	(1.85)
Year Ended 12/31/2017	$19.99	(0.15)	7.01	6.86	—	—	—
Institutional Class
Year Ended 12/31/2021	$34.25	0.04	3.56	3.60	(0.43)	(1.41)	(1.84)
Year Ended 12/31/2020	$29.00	0.03	5.31	5.34	(0.09)	—	(0.09)
Year Ended 12/31/2019	$23.81	0.17	7.78	7.95	(0.42)	(2.34)	(2.76)
Year Ended 12/31/2018	$29.25	0.14	(3.73)	(3.59)	—	(1.85)	(1.85)
Year Ended 12/31/2017	$21.61	0.09	7.62	7.71	(0.07)	—	(0.07)
Institutional 2 Class
Year Ended 12/31/2021	$34.57	0.06	3.60	3.66	(0.49)	(1.41)	(1.90)
Year Ended 12/31/2020	$29.24	0.08	5.34	5.42	(0.09)	—	(0.09)
Year Ended 12/31/2019	$24.01	0.18	7.86	8.04	(0.47)	(2.34)	(2.81)
Year Ended 12/31/2018	$29.44	0.11	(3.69)	(3.58)	—	(1.85)	(1.85)
Year Ended 12/31/2017	$21.76	0.11	7.66	7.77	(0.09)	—	(0.09)
Institutional 3 Class
Year Ended 12/31/2021	$34.56	0.09	3.59	3.68	(0.52)	(1.41)	(1.93)
Year Ended 12/31/2020	$29.22	0.07	5.36	5.43	(0.09)	—	(0.09)
Year Ended 12/31/2019	$24.00	0.20	7.86	8.06	(0.50)	(2.34)	(2.84)
Year Ended 12/31/2018	$29.42	0.17	(3.74)	(3.57)	—	(1.85)	(1.85)
Year Ended 12/31/2017	$21.74	(0.07)	7.86	7.79	(0.11)	—	(0.11)

Notes to Financial Highlights
(a)	Had the Investment Manager and/or Transfer Agent not waived fees and/or reimbursed a portion of expenses, total return would have been reduced.
(b)	In addition to the fees and expenses that the Fund bears directly, the Fund indirectly bears a pro rata share of the fees and expenses of any other funds in which it invests, if any. Such indirect expenses are not included in the Fund's reported expense ratios.
(c)	Ratios include line of credit interest expense which is less than 0.01%.
(d)	The benefits derived from expense reductions had an impact of less than 0.01%.

66 Prospectus 2022

Columbia Acorn International Select^SM

Financial Highlights (continued)

	Net asset value, end of period	Total return(a)	Total gross expense ratio to average net assets(b)	Total net expense ratio to average net assets(b)	Net investment income (loss) ratio to average net assets	Portfolio turnover	Net assets, end of period (000's)
Class A
Year Ended 12/31/2021	$35.43	10.49%	1.44% (c)	1.23% (c), (d)	(0.15%)	27%	$235,103
Year Ended 12/31/2020	$33.67	18.21%	1.48%	1.26% (d)	(0.10%)	68%	$230,519
Year Ended 12/31/2019	$28.58	33.37%	1.54% (c)	1.35% (c), (d)	0.34%	46%	$37,461
Year Ended 12/31/2018	$23.44	(12.46%)	1.54%	1.40% (d)	0.20%	48%	$26,073
Year Ended 12/31/2017	$28.89	35.30%	1.54%	1.40% (d)	0.07%	49%	$26,336
Advisor Class
Year Ended 12/31/2021	$36.35	10.78%	1.19% (c)	0.98% (c), (d)	0.11%	27%	$2,462
Year Ended 12/31/2020	$34.56	18.51%	1.23%	1.02% (d)	0.12%	68%	$2,748
Year Ended 12/31/2019	$29.26	33.73%	1.29% (c)	1.10% (c), (d)	0.63%	46%	$2,030
Year Ended 12/31/2018	$24.00	(12.26%)	1.29%	1.15% (d)	0.31%	48%	$1,201
Year Ended 12/31/2017	$29.46	35.67%	1.29%	1.15% (d)	0.30%	49%	$1,820
Class C
Year Ended 12/31/2021	$31.86	9.68%	2.19% (c)	1.98% (c), (d)	(0.93%)	27%	$2,146
Year Ended 12/31/2020	$30.40	17.37%	2.23%	2.02% (d)	(0.88%)	68%	$3,251
Year Ended 12/31/2019	$26.00	32.31%	2.29% (c)	2.10% (c), (d)	(0.42%)	46%	$2,493
Year Ended 12/31/2018	$21.48	(13.11%)	2.28%	2.15% (d)	(0.43%)	48%	$2,752
Year Ended 12/31/2017	$26.85	34.32%	2.29%	2.15% (d)	(0.64%)	49%	$5,027
Institutional Class
Year Ended 12/31/2021	$36.01	10.79%	1.19% (c)	0.98% (c), (d)	0.10%	27%	$159,876
Year Ended 12/31/2020	$34.25	18.50%	1.23%	1.02% (d)	0.12%	68%	$155,133
Year Ended 12/31/2019	$29.00	33.71%	1.29% (c)	1.10% (c), (d)	0.59%	46%	$88,922
Year Ended 12/31/2018	$23.81	(12.28%)	1.28%	1.15% (d)	0.47%	48%	$69,413
Year Ended 12/31/2017	$29.25	35.70%	1.29%	1.15% (d)	0.36%	49%	$89,266
Institutional 2 Class
Year Ended 12/31/2021	$36.33	10.87%	1.10% (c)	0.89% (c)	0.17%	27%	$51,805
Year Ended 12/31/2020	$34.57	18.63%	1.15%	0.93%	0.27%	68%	$77,420
Year Ended 12/31/2019	$29.24	33.82%	1.22% (c)	1.00% (c)	0.65%	46%	$3,392
Year Ended 12/31/2018	$24.01	(12.16%)	1.21%	1.06%	0.36%	48%	$1,200
Year Ended 12/31/2017	$29.44	35.72%	1.22%	1.08%	0.41%	49%	$614
Institutional 3 Class
Year Ended 12/31/2021	$36.31	10.93%	1.05% (c)	0.84% (c)	0.24%	27%	$28,694
Year Ended 12/31/2020	$34.56	18.67%	1.09%	0.89%	0.24%	68%	$27,064
Year Ended 12/31/2019	$29.22	33.90%	1.16% (c)	0.96% (c)	0.72%	46%	$13,861
Year Ended 12/31/2018	$24.00	(12.14%)	1.14%	1.02%	0.58%	48%	$8,627
Year Ended 12/31/2017	$29.42	35.81%	1.17%	1.03%	(0.24%)	49%	$7,732

Prospectus 2022 67

Columbia Acorn International Select^SM

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges

As noted in the Choosing a Share Class section of the prospectus, the sales charge reductions and waivers available to investors who purchase and hold their Fund shares through different financial intermediaries may vary. This Appendix A describes financial intermediary-specific reductions and/or waiver policies applicable to Fund shares purchased and held through the particular financial intermediary. A reduction and/or waiver that is specific to a particular financial intermediary is not available to Direct-at-Fund Accounts and does not apply in any case to non-omnibus positions wherever held. These reductions and/or waivers may apply to purchases, sales, and exchanges of Fund shares. A shareholder transacting in Fund shares through a financial intermediary identified below should carefully read the terms and conditions of the reductions and/or waivers. Please consult your financial intermediary with respect to any sales charge reduction/waiver described below.

The financial intermediary-specific information below may be provided by, or compiled from or based on information provided by, the financial intermediaries noted. While the Funds, the Investment Manager and the Distributor do not establish these financial intermediary-specific policies, our representatives are available to answer questions about these financial intermediary-specific policies and can direct you to the financial intermediary if you need help understanding them.

 Ameriprise Financial Services, LLC (Ameriprise Financial Services)

The following information has been provided by Ameriprise Financial Services:

Class A Shares Front-End Sales Charge Waivers Available at Ameriprise Financial Services:

The following information applies to Class A shares purchases if you have an account with or otherwise purchase Fund shares through Ameriprise Financial Services:

Shareholders purchasing Fund shares through an Ameriprise Financial Services brokerage account are eligible for the following front-end sales charge waivers, which may differ from those disclosed elsewhere in this prospectus or the Fund’s SAI:

■ Employer-sponsored retirement plans (e.g., 401(k) plans, 457 plans, employer-sponsored 403(b) plans, profit sharing and money purchase pension plans and defined benefit plans). For purposes of this provision, employer-sponsored retirement plans do not include SEP IRAs, Simple IRAs or SAR-SEPs.

■ Shares purchased through reinvestment of capital gains distributions and dividend reinvestment when purchasing shares of the same fund (but not any other fund within the Columbia Fund family).

■ Shares exchanged from Class C shares of the same fund in the month of or following the 7-year anniversary of the purchase date. To the extent that the Fund’s Class C Shares – Conversion to Class A Shares policy (stated outside this Appendix A) provides for a waiver with respect to exchanges of Class C shares or the conversion of Class C shares following a shorter holding period, that waiver will apply.

■ Employees and registered representatives of Ameriprise Financial Services or its affiliates and their immediate family members.

■ Shares purchased by or through qualified accounts (including IRAs, Coverdell Education Savings Accounts, 401(k)s, 403(b) TSCAs subject to ERISA and defined benefit plans) that are held by a covered family member, defined as an Ameriprise financial advisor and/or the advisor’s spouse, advisor’s lineal ascendant (mother, father, grandmother, grandfather, great grandmother, great grandfather), advisor’s lineal descendant (son, step-son, daughter, step-daughter, grandson, granddaughter, great grandson, great granddaughter) or any spouse of a covered family member who is a lineal descendant.

■ Shares purchased from the proceeds of redemptions from another fund in the Columbia Fund family, provided (1) the repurchase occurs within 90 days following the redemption, (2) the redemption and purchase occur in the same account, and (3) redeemed shares were subject to a front-end or deferred sales load (i.e. Rights of Reinstatement).

A-1 Prospectus 2022

Columbia Acorn International Select^SM

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

 Robert W. Baird & Co. Incorporated (Baird)

The following information has been provided by Baird:

Effective June 30, 2020, shareholders purchasing Columbia Fund shares through a Baird platform or account that maintains an omnibus position with the Fund will only be eligible for the following sales charge waivers (front-end sales charge waivers and CDSC waivers) and discounts, which may differ from those disclosed elsewhere in this prospectus or the Fund’s SAI. A reduction and/or waiver that is specific to Baird will not apply to non-omnibus positions.

Front-End Sales Charge Waivers on Class A Shares Available at Baird:

■ Shares purchased through reinvestment of capital gains distributions and dividend reinvestment when purchasing shares of the same Columbia Fund.

■ Share purchases by employees and registered representatives of Baird or its affiliates and their family members as designated by Baird.

■ Shares purchased with the proceeds of redemptions from another Columbia Fund, provided (1) the repurchase occurs within 90 days following the redemption, (2) the redemption and purchase occur in the same accounts, and (3) redeemed shares were subject to a front-end or deferred sales charge (known as rights of reinstatement).

■ A shareholder in the Fund’s Class C shares will have their shares converted at net asset value to Class A shares of the same Columbia Fund if the shares are no longer subject to CDSC and the conversion is in line with the policies and procedures of Baird.

■ Employer-sponsored retirement plans or charitable accounts in a transactional brokerage account at Baird, including 401(k) plans, 457 plans, employer-sponsored 403(b) plans, profit sharing and money purchase pension plans and defined benefit plans. For purposes of this provision, employer-sponsored retirement plans do not include SEP IRAs, Simple IRAs or SAR-SEPs.

CDSC Waivers on Class A and Class C Shares Available at Baird:

■ Shares sold due to death or disability of the shareholder.

■ Shares sold as part of a systematic withdrawal plan as described in this prospectus.

■ Shares purchased due to returns of excess contributions from an IRA account.

■ Shares sold as part of a required minimum distribution for IRA and retirement accounts due to the shareholder reaching the qualified age based on applicable IRS regulations.

■ Shares sold to pay Baird fees but only if the transaction is initiated by Baird.

■ Shares acquired through a right of reinstatement.

Front-End Sales Charge Discounts Available at Baird: Breakpoints and/or Rights of Accumulations:

■ Breakpoints as described in this prospectus.

■ Rights of accumulations which entitle shareholders to breakpoint discounts will be automatically calculated based on the aggregated holding of Columbia Fund assets held by accounts within the purchaser’s household at Baird. Eligible Columbia Fund assets not held at Baird may be included in the rights of accumulations calculation only if the shareholder notifies his or her financial advisor about such assets.

■ Letters of Intent (LOI) allow for breakpoint discounts based on anticipated purchases of Columbia Funds through Baird, over a 13-month period of time.

Prospectus 2022 A-2

Columbia Acorn International Select^SM

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

 Edward D. Jones & Co., L.P. (Edward Jones)

Policies Regarding Transactions Through Edward Jones

The following information has been provided by Edward Jones:

Effective on or after January 15, 2021, the following information supersedes prior information with respect to transactions and positions held in Columbia Fund shares through an Edward Jones system. Clients of Edward Jones (also referred to as "shareholders") purchasing Columbia Fund shares on the Edward Jones commission and fee-based platforms are eligible only for the following sales charge discounts (also referred to as "breakpoints") and waivers, which can differ from discounts and waivers described elsewhere in this prospectus or the Fund’s SAI or through another broker-dealer. In all instances, it is the shareholder's responsibility to inform Edward Jones at the time of purchase of any relationship, holdings of Columbia Funds and Future Scholars Program, or other facts qualifying the purchaser for discounts or waivers. Edward Jones can ask for documentation of such circumstance. Shareholders should contact Edward Jones if they have questions regarding their eligibility for these discounts and waivers.

Breakpoints

■ Breakpoint pricing, otherwise known as volume pricing, at dollar thresholds as described in this prospectus.

Rights of Accumulation (ROA)

■ The applicable sales charge on a purchase of Class A shares is determined by taking into account all share classes (except certain money market funds and any assets held in group retirement plans) of Columbia Funds and Future Scholars Program held by the shareholder or in an account grouped by Edward Jones with other accounts for the purpose of providing certain pricing considerations ("pricing groups"). If grouping assets as a shareholder, this includes all share classes held on the Edward Jones platform and/or held on another platform. The inclusion of eligible Columbia Fund assets in the ROA calculation is dependent on the shareholder notifying Edward Jones of such assets at the time of calculation. Money market funds are included only if such shares were sold with a sales charge at the time of purchase or acquired in exchange for shares purchased with a sales charge.

■ The employer maintaining a SEP IRA plan and/or SIMPLE IRA plan may elect to establish or change ROA for the IRA accounts associated with the plan to a plan-level grouping as opposed to including all share classes at a shareholder or pricing group level.

■ ROA is determined by calculating the higher of cost minus redemptions or market value (current shares x NAV).

Letter of Intent (LOI)

■ Through a LOI, shareholders can receive the sales charge and breakpoint discounts for purchases shareholders intend to make over a 13-month period from the date Edward Jones receives the LOI. The LOI is determined by calculating the higher of cost or market value of qualifying holdings at LOI initiation in combination with the value that the shareholder intends to buy over a 13-month period to calculate the front-end sales charge and any breakpoint discounts. Each purchase the shareholder makes during that 13-month period will receive the sales charge and breakpoint discount that applies to the total amount. The inclusion of eligible Columbia Fund assets in the LOI calculation is dependent on the shareholder notifying Edward Jones of such assets at the time of calculation. Purchases made before the LOI is received by Edward Jones are not adjusted under the LOI and will not reduce the sales charge previously paid. Sales charges will be adjusted if LOI is not met.

■ If the employer maintaining a SEP IRA plan and/or SIMPLE IRA plan has elected to establish or change ROA for the IRA accounts associated with the plan to a plan-level grouping, LOIs will also be at the plan-level and may only be established by the employer.

A-3 Prospectus 2022

Columbia Acorn International Select^SM

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

Sales Charge Waivers

Sales charges are waived for the following shareholders and in the following situations:

■ Associates of Edward Jones and its affiliates and their family members who are in the same pricing group (as determined by Edward Jones under its policies and procedures) as the associate. This waiver will continue for the remainder of the associate's life if the associate retires from Edward Jones in good-standing and remains in good standing pursuant to Edward Jones' policies and procedures.

■ Shares purchased in an Edward Jones fee-based program.

■ Shares purchased through reinvestment of capital gains distributions and dividend reinvestment.

■ Shares purchased from the proceeds of redeemed shares of Columbia Funds so long as the following conditions are met: 1) the proceeds are from the sale of shares within 60 days of the purchase, and 2) the sale and purchase are made in the same share class and the same account or the purchase is made in an individual retirement account with proceeds from liquidations in a non-retirement account.

■ Shares exchanged into Class A shares from another share class so long as the exchange is into the same fund and was initiated at the discretion of Edward Jones. Edward Jones is responsible for any remaining CDSC due to the fund company, if applicable. Any future purchases are subject to the applicable sales charge as disclosed in this prospectus.

■ Exchanges from Class C shares to Class A shares of the same fund, generally, in the 84th month following the anniversary of the purchase date or earlier at the discretion of Edward Jones.

Contingent Deferred Sales Charge (CDSC) Waivers

If the shareholder purchases shares that are subject to a CDSC and those shares are redeemed before the CDSC is expired, the shareholder is responsible to pay the CDSC except in the following conditions:

■ The death or disability of the shareholder.

■ Systematic withdrawals with up to 10% per year of the account value.

■ Return of excess contributions from an Individual Retirement Account (IRA).

■ Shares sold as part of a required minimum distribution for IRA and retirement accounts if the redemption is taken in or after the year the shareholder reaches qualified age based on applicable IRS regulations.

■ Shares sold to pay Edward Jones fees or costs in such cases where the transaction is initiated by Edward Jones.

■ Shares exchanged in an Edward Jones fee-based program.

■ Shares acquired through NAV reinstatement.

■ Shares redeemed at the discretion of Edward Jones for Minimum Balances, as described below.

Other Important Information Regarding Transactions Through Edward Jones

Minimum Purchase Amounts

■ Initial purchase minimum: $250

■ Subsequent purchase minimum: none

Minimum Balances

■ Edward Jones has the right to redeem at its discretion Fund holdings with a balance of $250 or less. The following are examples of accounts that are not included in this policy:

■ A fee-based account held on an Edward Jones platform.

■ A 529 account held on an Edward Jones platform.

■ An account with an active systematic investment plan or LOI.

Prospectus 2022 A-4

Columbia Acorn International Select^SM

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

Exchanging Share Classes

■ At any time it deems necessary, Edward Jones has the authority to exchange at NAV a shareholder's holdings in the Fund to Class A shares.

 Janney Montgomery Scott LLC (Janney)

The following information has been provided by Janney:

Effective May 1, 2020, if you purchase Columbia Fund shares through a Janney brokerage account, you will be eligible for the following load waivers (front-end sales charge waivers and CDSC, or back-end sales charge, waivers) and discounts, which may differ from those disclosed elsewhere in this prospectus or the Fund’s SAI. A reduction and/or waiver that is specific to Janney does not apply to non-omnibus positions.

Front-End Sales Charge* Waivers on Class A Shares Available at Janney

■ Shares purchased through reinvestment of capital gains distributions and dividend reinvestment when purchasing shares of the same fund (but not any other Columbia Fund).

■ Shares purchased by employees and registered representatives of Janney or its affiliates and their family members as designated by Janney.

■ Shares purchased from the proceeds of redemptions from another Columbia Fund, provided (1) the repurchase occurs within ninety (90) days following the redemption, (2) the redemption and purchase occur in the same account, and (3) redeemed shares were subject to a front-end or deferred sales load (i.e., right of reinstatement).

■ Employer-sponsored retirement plans (e.g., 401(k) plans, 457 plans, employer-sponsored 403(b) plans, profit sharing and money purchase pension plans and defined benefit plans). For purposes of this provision, employer-sponsored retirement plans do not include SEP IRAs, Simple IRAs, SAR-SEPs or Keogh plans.

■ Shares acquired through a right of reinstatement.

■ Class C shares that are no longer subject to a CDSC and are converted to Class A shares of the same fund pursuant to Janney’s policies and procedures.

CDSC Waivers on Class A and C Shares Available at Janney

■ Shares sold upon the death or disability of the shareholder.

■ Shares sold as part of a systematic withdrawal plan as described in this prospectus.

■ Shares purchased in connection with a return of excess contributions from an IRA account.

■ Shares sold as part of a required minimum distribution for IRA and retirement accounts if the redemption is taken in or after the year the shareholder reaches qualified age based on applicable IRS regulations.

■ Shares sold to pay Janney fees but only if the transaction is initiated by Janney.

■ Shares acquired through a right of reinstatement.

■ Shares exchanged into the same share class of a different fund.

Front-End Sales Charge* Discounts Available at Janney: Breakpoints, Rights of Accumulation, and/or Letters of Intent

■ Breakpoints as described in this prospectus.

■ Rights of accumulation (“ROA”), which entitle shareholders to breakpoint discounts, will be automatically calculated based on the aggregated holding of Columbia Fund assets held by accounts within the purchaser’s household at Janney. Eligible Columbia Fund assets not held at Janney may be included in the ROA calculation only if the shareholder notifies his or her financial advisor about such assets.

■ Letters of intent which allow for breakpoint discounts based on anticipated purchases within the Columbia Funds, over a 13-month time period. Eligible Columbia Fund assets not held at Janney may be included in the calculation of letters of intent only if the shareholder notifies his or her financial advisor about such assets.

A-5 Prospectus 2022

Columbia Acorn International Select^SM

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

* Also referred to as an “initial sales charge”.

 Merrill Lynch Pierce, Fenner & Smith Incorporated (Merrill Lynch)

The following information has been provided by Merrill Lynch:

Shareholders purchasing Columbia Fund shares through a Merrill Lynch platform or account will be eligible only for the following load waivers (front-end sales charge waivers and contingent deferred, or back-end, sales charge waivers) and discounts, which may differ from those disclosed elsewhere in this prospectus or the Fund’s SAI:

Front-End Load Discounts Available at Merrill Lynch:

Merrill Lynch makes available breakpoint discounts on shares of the Fund through:

■ Breakpoints as described in this prospectus.

■ Rights of Accumulation (ROA) which entitle shareholders to breakpoint discounts as described in this prospectus will be automatically calculated based on the aggregated holding of Columbia Fund assets held by accounts (including 529 program holdings, where applicable) within the purchaser’s household at Merrill Lynch. Eligible Columbia Fund assets not held at Merrill Lynch may be included in the ROA calculation only if the shareholder notifies his or her financial advisor about such assets.

■ Letters of Intent (LOI) which allow for breakpoint discounts based on anticipated purchases of Columbia Funds, through Merrill Lynch, over a 13-month period of time (if applicable).

Front-End Sales Load Waivers on Class A Shares Available at Merrill Lynch:

■ Employer-sponsored retirement, deferred compensation and employee benefit plans (including health savings accounts) and trusts used to fund those plans, provided that the shares are not held in a commission-based brokerage account and shares are held for the benefit of the plan.

■ Shares purchased by a 529 Plan (does not include 529 Plan units or 529-specific share classes or equivalents).

■ Shares purchased through a Merrill Lynch affiliated investment advisory program.

■ Shares exchanged due to the holdings moving from a Merrill Lynch affiliated investment advisory program to a Merrill Lynch brokerage (non-advisory) account pursuant to Merrill Lynch’s policies relating to sales load discounts and waivers.

■ Shares purchased by third party investment advisors on behalf of their advisory clients through Merrill Lynch’s platform.

■ Shares of funds purchased through the Merrill Edge Self-Directed platform (if applicable).

■ Shares purchased through reinvestment of capital gains distributions and dividend reinvestment when purchasing shares of the same fund (but not any other Columbia Fund).

■ Shares exchanged from Class C (i.e., level-load) shares of the same fund pursuant to Merrill Lynch’s policies relating to sales load discounts and waivers.

■ Employees and registered representatives of Merrill Lynch or its affiliates and their family members.

■ Directors or Trustees of the Fund, and employees of the Fund’s investment adviser or any of its affiliates, as described in this prospectus.

■ Eligible shares purchased from the proceeds of redemptions from another Columbia Fund, provided (1) the repurchase occurs within 90 days following the redemption, (2) the redemption and purchase occur in the same account, and (3) redeemed shares were subject to a front-end or deferred sales load (known as Rights of Reinstatement). Automated transactions (i.e. systematic purchases and withdrawals) and purchases made after shares are automatically sold to pay Merrill Lynch’s account maintenance fees are not eligible for reinstatement.

CDSC Waivers on Class A and C Shares Available at Merrill Lynch:

■ Death or disability of the shareholder.

Prospectus 2022 A-6

Columbia Acorn International Select^SM

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

■ Shares sold as part of a systematic withdrawal plan as described in this prospectus.

■ Return of excess contributions from an IRA Account.

■ Shares sold as part of a required minimum distribution for IRA and retirement accounts pursuant to the Internal Revenue Code.

■ Shares sold to pay Merrill Lynch fees but only if the transaction is initiated by Merrill Lynch.

■ Shares acquired through a right of reinstatement.

■ Shares held in retirement brokerage accounts, that are exchanged for a lower cost share class due to transfer to certain fee based accounts or platforms (applicable to Class A and Class C shares only).

■ Shares received through an exchange due to the holdings moving from a Merrill Lynch affiliated investment advisory program to a Merrill Lynch brokerage (non-advisory) account pursuant to Merrill Lynch’s policies relating to sales load discounts and waivers.

 Morgan Stanley Smith Barney, LLC (Morgan Stanley Wealth Management)

The following information has been provided by Morgan Stanley Wealth Management:

Effective July 1, 2018, shareholders purchasing Columbia Fund shares through a Morgan Stanley Wealth Management transactional brokerage account will be eligible only for the following front-end sales charge waivers with respect to Class A shares, which may differ from and may be more limited than those disclosed elsewhere in this prospectus or the Fund’s SAI.

Front-End Sales Charge Waivers on Class A Shares Available at Morgan Stanley Wealth Management Effective July 1, 2018:

■ Employer-sponsored retirement plans (e.g., 401(k) plans, 457 plans, employer-sponsored 403(b) plans, profit sharing and money purchase pension plans and defined benefit plans).  For purposes of this provision, employer-sponsored retirement plans do not include SEP IRAs, Simple IRAs, SAR-SEPs or Keogh plans.

■ Morgan Stanley employee and employee-related accounts according to Morgan Stanley’s account linking rules.

■ Shares purchased through reinvestment of dividends and capital gains distributions when purchasing shares of the same fund.

■ Shares purchased through a Morgan Stanley self-directed brokerage account.

■ Class C (i.e., level-load) shares that are no longer subject to a CDSC and are exchanged for Class A shares of the same fund pursuant to Morgan Stanley Wealth Management’s share class exchange program.

■ Shares purchased from the proceeds of redemptions from another Columbia Fund, provided (i) the repurchase occurs within 90 days following the redemption, (ii) the redemption and purchase occur in the same account, and (iii) redeemed shares were subject to a front-end or deferred sales charge.

 Raymond James & Associates, Inc., Raymond James Financial Services, Inc. and each entity’s affiliates (Raymond James)

The following information has been provided by Raymond James:

Intermediary-Defined Sales Charge Waiver Policies:

The availability of certain initial or deferred sales charge waivers and discounts may depend on the particular financial intermediary or type of account through which you purchase or hold Columbia Fund shares.

Intermediaries may have different policies and procedures regarding the availability of front-end sales load waivers or contingent deferred (back-end) sales load (CDSC) waivers, which are discussed below. In all instances, it is the purchaser’s responsibility to notify the Fund or the purchaser’s financial intermediary at the time of purchase of any

A-7 Prospectus 2022

Columbia Acorn International Select^SM

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

relationship or other facts qualifying the purchaser for sales charge waivers or discounts. For waivers and discounts not available through a particular intermediary, shareholders will have to purchase Columbia Fund shares directly from the Fund or through another intermediary to receive these waivers or discounts.

Raymond James:

Effective March 1, 2019, shareholders purchasing Columbia Fund shares through a Raymond James platform or account, or through an introducing broker-dealer or independent registered investment adviser for which Raymond James provides trade execution, clearance, and/or custody services, will be eligible only for the following load waivers (front-end sales charge waivers and contingent deferred, or back-end, sales charge waivers) and discounts, which may differ from those disclosed elsewhere in this prospectus or the Fund’s SAI.

Front-End Sales Load Waivers on Class A Shares Available at Raymond James:

■ Shares purchased in an investment advisory program.

■ Shares purchased within the Columbia Funds through a systematic reinvestment of capital gains and dividend distributions.

■ Employees and registered representatives of Raymond James or its affiliates and their family members as designated by Raymond James.

■ Shares purchased from the proceeds of redemptions within the Columbia Funds, provided (1) the repurchase occurs within 90 days following the redemption, (2) the redemption and purchase occur in the same account, and (3) redeemed shares were subject to a front-end or deferred sales load (known as Rights of Reinstatement).

■ A shareholder in the Fund’s Class C shares will have their shares converted at net asset value to Class A shares (or the appropriate share class) of the Fund if the shares are no longer subject to a CDSC and the conversion is in line with the policies and procedures of Raymond James.

CDSC Waivers on Class A and Class C Shares Available at Raymond James:

■ Death or disability of the shareholder.

■ Shares sold as part of a systematic withdrawal plan as described in this prospectus.

■ Return of excess contributions from an IRA Account.

■ Shares sold as part of a required minimum distribution for IRA and retirement accounts due to the shareholder reaching the qualified age based on applicable IRS regulations as described in this prospectus.

■ Shares sold to pay Raymond James fees but only if the transaction is initiated by Raymond James.

■ Shares acquired through a right of reinstatement.

Front-End Load Discounts Available at Raymond James: Breakpoints, Rights of Accumulation and/or Letters of Intent:

■ Breakpoints as described in this prospectus.

■ Rights of accumulation which entitle shareholders to breakpoint discounts will be automatically calculated based on the aggregated holding of Columbia Fund assets held by accounts within the purchaser’s household at Raymond James. Eligible Columbia Fund assets not held at Raymond James may be included in the calculation of rights of accumulation only if the shareholder notifies his or her financial advisor about such assets.

■ Letters of intent which allow for breakpoint discounts based on anticipated purchases within the Columbia Funds, over a 13-month time period. Eligible Columbia Fund assets not held at Raymond James may be included in the calculation of letters of intent only if the shareholder notifies his or her financial advisor about such assets.

Prospectus 2022 A-8

Columbia Acorn International Select^SM

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

 Stifel Financial Corp. (Stifel)

The following information has been provided by Stifel:

Effective June 30, 2020, Class C shares of Columbia Funds that were purchased through a Stifel platform or account that maintains an omnibus position with the Fund that are no longer subject to a CDSC are exchanged to Class A shares of the same Columbia Fund pursuant to Stifel’s policies and procedures. This does not apply to non-omnibus positions.

 U.S. Bancorp Investments, Inc. (USBI)

The following information has been provided by USBI:

Effective September of 2021, shareholders purchasing Columbia Fund shares through a USBI platform or who own shares for which USBI is the broker-dealer, where the shares are held in an omnibus account, will only be eligible for the following front-end sales charge waivers and discounts, which may differ from those disclosed elsewhere in this prospectus or the Fund’s SAI.

All other sales charge waivers and reduction described elsewhere in this prospectus or the Fund’s SAI still apply.

USBI Conversion of Class C shares

Class C (i.e., level-load) shares that are no longer subject to a contingent deferred sales charge are systematically converted to the Class A shares of the same fund pursuant to USBI’s share class exchange policy.

 Additional Sales Charge Reductions and/or Waivers Available at Certain Financial Intermediaries

Shareholders purchasing Columbia Fund shares through a platform or account of RBC Capital Markets, LLC are eligible for the following sales charge waiver:

Class A Shares Front-End Sales Charge Waiver Available at RBC Capital Markets, LLC:

■ For employer-sponsored retirement plans held through a commissionable brokerage account, Class A shares are available at NAV (i.e., without a sales charge). For this purpose, employer-sponsored retirement plans include, but are not limited to, 401(k) plans, 457 plans, employer-sponsored 403(b) plans, profit sharing and money purchase pension plans and defined benefit plans. For purposes of this provision, employer-sponsored retirement plans do not include SEP IRAs, Simple IRAs, SAR-SEPs or Keogh plans.

A-9 Prospectus 2022

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Columbia Acorn International Select^SM

P.O. Box 219104
Kansas City, MO 64121-9104

Columbia Acorn Family of Funds

Additional Information About the Fund

Additional information about the Fund’s investments is available in the Fund’s annual and semiannual reports to shareholders. In the annual report, you will find a discussion of the market conditions and investment strategies that significantly affected the Fund’s performance during its last fiscal year. The SAI also provides additional information about the Fund and its policies. The SAI, which has been filed with the SEC, is legally part of this prospectus (incorporated by reference). To obtain these documents free of charge, to request other information about the Fund and to make shareholder inquiries, please contact the Fund as follows:

By Mail:  Columbia Management Investment Services Corp.
P.O. Box 219104
Kansas City, MO 64121-9104

By Telephone: 800.345.6611

Online: columbiathreadneedleus.com

Shareholder Communications with the Board

The Fund’s Board of Trustees has adopted procedures by which shareholders may communicate with the Board. Shareholders who wish to communicate with the Board should send their written communications to the Board by mail, c/o Columbia Wanger Asset Management, LLC, 71 S. Wacker Drive, Suite 2500, Chicago, IL 60606, Attention: Secretary. Shareholder communications must (i) be in writing, (ii) identify the Columbia Acorn Fund to which the communication relates and (iii) state the particular class of shares and number of shares held by the communicating shareholder.

Obtaining Additional Information from the SEC

Reports and other information about the Fund are also available in the EDGAR Database on the SEC’s website at http://www.sec.gov. You can receive copies of this information, for a duplication fee, by electronic request at the following e-mail address: publicinfo@sec.gov.

The investment company registration number of Columbia Acorn Trust, of which the Fund is a series, is 811-01829.

Columbia Threadneedle Investments is the global brand name of the Columbia and Threadneedle group of companies.
The Fund is distributed by Columbia Management Investment Distributors, Inc., 290 Congress Street, Boston, MA 02210.

© 2022 Columbia Management Investment Advisers, LLC. All rights reserved.

PRO112_12_M01_(05/22)

 

Prospectus

May 1, 2022

Columbia Acorn Family of Funds

Managed by Columbia Wanger Asset Management, LLC

Columbia
  Acorn USA®

Class	Ticker Symbol
A	LAUAX
Advisor (Class Adv)	CUSAX
C	LAUCX

Class	Ticker Symbol
Institutional (Class Inst)	AUSAX
Institutional 2 (Class Inst2)	CYSRX
Institutional 3 (Class Inst3)	CUSYX

As with all mutual funds, the Securities and Exchange Commission (SEC) has not approved or disapproved these securities or passed upon the adequacy of this prospectus. Any representation to the contrary is a criminal offense.

Table of Contents

Summary of the Fund	3
Investment Objective	3
Fees and Expenses of the Fund	3
Principal Investment Strategies	4
Principal Risks	5
Performance Information	8
Fund Management	9
Purchase and Sale of Fund Shares	10
Tax Information	10
Payments to Broker-Dealers and Other Financial Intermediaries	10
More Information About the Fund	11
Investment Objective	11
Principal Investment Strategies	11
Principal Risks	11
Additional Investment Strategies and Policies	15
Board of Trustees	21
Primary Service Provider Contracts	21
Other Roles and Relationships of Ameriprise Financial and its Affiliates — Certain Conflicts of Interest	24
Certain Legal Matters	25
Choosing a Share Class	26
The Funds	26
Summary of Share Class Features	26
Sales Charges and Commissions	32
Reductions/Waivers of Sales Charges	35
Distribution and Service Fees	39
Financial Intermediary Compensation	40
Buying, Selling and Exchanging Shares	42
Share Price Determination	42
Transaction Rules and Policies	43
Opening an Account and Placing Orders	47
Buying Shares	49
Selling Shares	54
Exchanging Shares	56
Distributions and Taxes	59
Distributions to Shareholders	59
Taxes	60
Financial Highlights	63
Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges	A-1

2

Columbia Acorn USA®

Summary of the Fund

Investment Objective

Columbia Acorn USA^® (the Fund) seeks long-term capital appreciation.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below. You may qualify for sales charge discounts if you and members of your immediate family invest, or agree to invest in the future, at least $50,000 in certain classes of shares of eligible funds distributed by Columbia Management Investment Distributors, Inc. (the Distributor). More information is available about these and other sales charge discounts and waivers from your financial intermediary, and can be found in the Choosing a Share Class section beginning on page 26 of the Fund’s prospectus, in Appendix A to the prospectus beginning on page A-1 and in Appendix S to the Statement of Additional Information (SAI) under Sales Charge Waivers beginning on page S-1.

Shareholder Fees (fees paid directly from your investment)
	Class A	Class C	Classes Adv, Inst, Inst2 and Inst3
Maximum sales charge (load) imposed on purchases (as a % of offering price)	5.75%	None	None
Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)	1.00%(a)	1.00%(b)	None

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
	Class A	Class Adv	Class C	Class Inst	Class Inst2	Class Inst3
Management fees(c)	0.74%	0.74%	0.74%	0.74%	0.74%	0.74%
Distribution and/or service (12b-1) fees	0.25%	0.00%	1.00%	0.00%	0.00%	0.00%
Other expenses	0.23%	0.23%	0.23%	0.23%	0.19%	0.13%
Total annual Fund operating expenses(d)	1.22%	0.97%	1.97%	0.97%	0.93%	0.87%
Less: Fee waivers and/or expense reimbursements(e)	(0.14%)	(0.14%)	(0.14%)	(0.14%)	(0.12%)	(0.11%)
Total annual Fund operating expenses after fee waivers and/or expense reimbursements	1.08%	0.83%	1.83%	0.83%	0.81%	0.76%

(a)	This charge is imposed on certain investments of between $1 million and $50 million redeemed within 18 months after purchase, as follows: 1.00% if redeemed within 12 months after purchase, and 0.50% if redeemed more than 12, but less than 18, months after purchase, with certain limited exceptions.
(b)	This charge applies to redemptions within 12 months after purchase, with certain limited exceptions.

(c)	Management fees have been restated to reflect the current management fee rate.
(d)	“Total annual Fund operating expenses” include acquired fund fees and expenses (expenses the Fund incurs indirectly through its investments in other investment companies) and may be higher than the ratio of expenses to average net assets shown in the Financial Highlights section of this prospectus because the ratio of expenses to average net assets does not include acquired fund fees and expenses.
(e)	Columbia Wanger Asset Management, LLC (the Investment Manager) has contractually agreed to waive fees and reimburse certain expenses of the Fund, through April 30, 2023, so that ordinary operating expenses (excluding transaction costs and certain other investment-related expenses, interest and fees on borrowings and expenses associated with the Fund’s investment in other investment companies, if any) do not exceed the annual rates of 1.08% for Class A shares, 0.83% for Class Adv shares, 1.83% for Class C shares, 0.83% for Class Inst shares, 0.81% for Class Inst2 shares and 0.76% for Class Inst3 shares. This arrangement may only be amended or terminated with approval from the Fund’s Board of Trustees and the Investment Manager. The fee waivers and/or expense reimbursements shown in the table also reflect the contractual agreement of the Fund’s transfer agent, Columbia Management Investment Services Corp. (the Transfer Agent), to waive a portion of its fees through April 30, 2023, such that the Fund’s transfer agency fees do not exceed the annual rate of 0.08% of the average daily net assets of each share class other than Class Inst2 and Class Inst3. This arrangement may be terminated at the sole discretion of the Fund’s Board of Trustees.

Prospectus 2022 3

Columbia Acorn USA®

Summary of the Fund (continued)

 Example

The following example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example illustrates the hypothetical expenses that you would incur over the time periods indicated, and assumes that:

■ you invest $10,000 in the applicable class of Fund shares for the periods indicated,

■ your investment has a 5% return each year, and

■ the Fund’s total annual operating expenses remain the same as shown in the Annual Fund Operating Expenses table above.

Since the waivers and/or reimbursements shown in the Annual Fund Operating Expenses table above expire as indicated in the preceding table, they are only reflected in the 1 year example and the first year of the other examples. Although your actual costs may be higher or lower, based on the assumptions listed above, your costs would be:

	1 year	3 years	5 years	10 years
Class A (whether or not shares are redeemed)	$679	$927	$1,194	$1,956
Class Adv (whether or not shares are redeemed)	$85	$295	$523	$1,177
Class C (assuming redemption of all shares at the end of the period)	$286	$605	$1,049	$2,090
Class C (assuming no redemption of shares)	$186	$605	$1,049	$2,090
Class Inst (whether or not shares are redeemed)	$85	$295	$523	$1,177
Class Inst2 (whether or not shares are redeemed)	$83	$284	$503	$1,132
Class Inst3 (whether or not shares are redeemed)	$78	$267	$471	$1,062

Portfolio Turnover

The Fund may pay transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 69% of the average value of its portfolio.

Principal Investment Strategies

Under normal circumstances, the Fund invests at least 80% of its net assets (including the amount of any borrowings for investment purposes) in U.S. companies.

Under normal circumstances, the Fund invests a majority of its net assets in the common stock of small- and mid-sized companies with market capitalizations generally in the range of market capitalizations in the Russell 2500 Growth Index, the Fund's benchmark, (the Index) at the time of purchase (between $21.5 million and $30 billion as of March 31, 2022). The market capitalization range and composition of companies in the Index are subject to change. As such, the size of the companies in which the Fund invests may change. The Fund determines a company’s market capitalization at the time of investment. As long as a majority of its net assets are invested in companies within the Index, the Fund may continue to hold and make new investments in a security even if the company’s market capitalization grows beyond the market capitalization of the largest company within the Index or falls below the market capitalization of the smallest company within the Index. 

Columbia Wanger Asset Management, LLC, the Fund's investment adviser (the Investment Manager), believes that stocks of small- and mid-sized companies, which generally are not as well known by financial analysts as larger companies, may offer higher return potential than stocks of larger companies. The Fund invests the majority of its assets in U.S. companies, but also may invest up to 20% of its total assets in foreign companies in developed 

4 Prospectus 2022

Columbia Acorn USA®

Summary of the Fund (continued)

markets (for example, Japan, Canada and the United Kingdom) and in emerging markets (for example, China, India and Brazil). The Investment Manager from time to time emphasizes one or more sectors in selecting the Fund’s investments, including the consumer discretionary, health care, and information technology sectors. 

The Investment Manager typically seeks companies with: 

■ A strong business franchise that offers growth potential. 

■ Products and services in which the company has a competitive advantage. 

■ A stock price the Investment Manager believes is reasonable relative to the assets and earning power of the company. 

The Investment Manager may sell a portfolio holding if the security reaches the Investment Manager's price target, if the company has a deterioration of fundamentals, such as failing to meet key operating benchmarks, or if the Investment Manager believes other securities are more attractive. The Investment Manager also may sell a portfolio holding to fund redemptions. 

Principal Risks

An investment in the Fund involves risks, including those described below, among others. There is no assurance that the Fund will achieve its investment objective and you may lose money. The value of the Fund’s holdings may decline, and the Fund’s net asset value (NAV) and share price may go down. An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Active Management Risk. The Investment Manager’s active management of the Fund could cause the Fund to underperform its benchmark index and/or other funds with similar investment objectives and/or strategies.

Small- and Mid-Cap Company Securities Risk. Investments in small- and mid-cap companies often involve greater risks than investments in larger, more established companies because small- and mid-cap companies tend to have less predictable earnings and may lack the management experience, financial resources, product diversification and competitive strengths of larger companies. Securities of small- and mid-cap companies may be less liquid and more volatile than the securities of larger companies.

Market Risk. The Fund may incur losses due to declines in the value of one or more securities in which it invests. These declines may be due to factors affecting a particular issuer, or the result of, among other things, political, regulatory, market, economic or social developments affecting the relevant market(s) more generally. In addition, turbulence in financial markets and reduced liquidity in equity, credit and/or fixed income markets may negatively affect many issuers, which could adversely affect the Fund’s ability to price or value hard-to-value assets in thinly traded and closed markets and could cause significant redemptions and operational challenges. Global economies and financial markets are increasingly interconnected, and conditions and events in one country, region or financial market may adversely impact issuers in a different country, region or financial market. These risks may be magnified if certain events or developments adversely interrupt the global supply chain; in these and other circumstances, such risks might affect companies worldwide. As a result, local, regional or global events such as terrorism, war, other conflicts, natural disasters, disease/virus outbreaks and epidemics or other public health issues, recessions, depressions or other events – or the potential for such events – could have a significant negative impact on global economic and market conditions. 

The large-scale invasion of Ukraine by Russia in February 2022 has resulted in sanctions and market disruptions including declines in regional and global stock and commodity markets and significant devaluations of Russian currency. The extent and duration of the military action are impossible to predict but could be significant. Market disruption caused by the Russian military action, and any counter measures or responses thereto (including international sanctions, a downgrade in the country’s credit rating, purchasing and financing restrictions, boycotts, tariffs, changes in consumer or purchaser preferences, cyberattacks and espionage) could have severe adverse impacts on regional and/or global securities and commodities markets, including markets for oil and natural gas. These impacts may include reduced market liquidity, distress in credit markets, further disruption of global supply chains, increased risk of inflation, and limited access to investments in certain international markets and/or issuers. These developments and other related events could negatively impact Fund performance. 

Prospectus 2022 5

Columbia Acorn USA®

Summary of the Fund (continued)

The pandemic caused by coronavirus disease 2019 and its variants (COVID-19) has resulted in, and may continue to result in, significant global economic and societal disruption and market volatility due to disruptions in market access, resource availability, facilities operations, imposition of tariffs, export controls and supply chain disruption, among others. Such disruptions may be caused, or exacerbated by, quarantines and travel restrictions, workforce displacement and loss in human and other resources. The uncertainty surrounding the magnitude, duration, reach, costs and effects of the global pandemic, as well as actions that have been or could be taken by governmental authorities or other third parties, present unknowns that are yet to unfold. The impacts, as well as the uncertainty over impacts to come, of COVID-19 – and any other infectious illness outbreaks, epidemics and pandemics that may arise in the future – could negatively affect global economies and markets in ways that cannot necessarily be foreseen. In addition, the impact of infectious illness outbreaks and epidemics in less developed countries may be greater due to generally less established healthcare systems, governments and financial markets. Public health crises caused by the COVID-19 outbreak may exacerbate other pre-existing political, social and economic risks in certain countries or globally. The disruptions caused by COVID-19 could prevent the Fund from executing advantageous investment decisions in a timely manner and negatively impact the Fund’s ability to achieve its investment objective. Any such events could have a significant adverse impact on the value and risk profile of the Fund. 

Issuer Risk. An issuer in which the Fund invests may perform poorly, and the value of its securities may therefore decline, which may negatively affect the Fund’s performance. Underperformance of an issuer may be caused by poor management decisions, competitive pressures, breakthroughs in technology, reliance on suppliers, labor problems or shortages, corporate restructurings, fraudulent disclosures, natural disasters, military confrontations and actions, war, terrorism, disease/virus outbreaks and epidemics or other events, conditions and factors. 

Growth Securities Risk. Growth securities typically trade at a higher multiple of earnings than other types of equity securities. Accordingly, the market values of growth securities may never reach their expected market value and may decline in price. In addition, growth securities, at times, may not perform as well as value securities or the stock market in general, and may be out of favor with investors for varying periods of time. 

Liquidity and Trading Volume Risk. Because the Fund may invest a percentage of its assets in foreign securities, including in emerging markets, it may be subject to the liquidity and trading volume risks associated with international investing, including in emerging markets. Due to market conditions, including uncertainty regarding the price of a security, it may be difficult for the Fund to buy or sell foreign portfolio securities at a desirable time or price, which could result in investment losses and may affect the value of your investment in the Fund. This risk of portfolio illiquidity is heightened with respect to small- and mid-cap securities, generally, and foreign small- and mid-cap securities in particular. The Fund may have to lower the selling price, liquidate other investments, or forego another, more appealing investment opportunity as a result of illiquidity in the markets. The Fund may also be limited in its ability to execute favorable trades in foreign portfolio securities in response to changes in share prices and fundamentals, and may be forced to dispose of securities under disadvantageous circumstances and at a loss. As the Fund grows in size or, conversely, if it faces significant redemption pressure, these considerations take on increasing significance and may adversely impact performance. 

Sector Risk. At times, the Fund may have a significant portion of its assets invested in securities of companies conducting business within one or more economic sectors, including the consumer discretionary, health care, and information technology sectors. Companies in the same sector may be similarly affected by economic, regulatory, political or market events or conditions, which may make the Fund more vulnerable to unfavorable developments in that sector than funds that invest more broadly. Generally, the more broadly the Fund invests, the more it spreads risk and potentially reduces the risks of loss and volatility. 

■ Consumer Discretionary Sector. The Fund is more susceptible to the particular risks that may affect companies in the consumer discretionary sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the consumer discretionary sector are subject to certain risks, including fluctuations in the performance of the overall domestic and international economy, interest rate changes, increased competition and consumer confidence. Performance of such companies may be affected by factors including reduced disposable household income, reduced consumer spending, and changing demographics and consumer tastes. 

6 Prospectus 2022

Columbia Acorn USA®

Summary of the Fund (continued)

■ Health Care Sector. The Fund is more susceptible to the particular risks that may affect companies in the health care sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the health care sector are subject to certain risks, including restrictions on government reimbursement for medical expenses, government approval of medical products and services, competitive pricing pressures, and the rising cost of medical products and services (especially for companies dependent upon a relatively limited number of products or services), among others. Performance of such companies may be affected by factors including, government regulation, obtaining and protecting patents (or the failure to do so), product liability and other similar litigation as well as product obsolescence. 

■ Information Technology Sector. The Fund is more susceptible to the particular risks that may affect companies in the information technology sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the information technology sector are subject to certain risks, including the risk that new services, equipment or technologies will not be accepted by consumers and businesses or will become rapidly obsolete. Performance of such companies may be affected by factors including obtaining and protecting patents (or the failure to do so) and significant competitive pressures, including aggressive pricing of their products or services, new market entrants, competition for market share and short product cycles due to an accelerated rate of technological developments. Such competitive pressures may lead to limited earnings and/or falling profit margins. As a result, the value of their securities may fall or fail to rise. In addition, many information technology sector companies have limited operating histories and prices of these companies’ securities historically have been more volatile than other securities, especially over the short term. Some companies in the information technology sector are facing increased government and regulatory scrutiny and may be subject to adverse government or regulatory action, which could negatively impact the value of their securities. 

Foreign Securities Risk. Investments in or exposure to securities of foreign companies may involve heightened risks relative to investments in or exposure to securities of U.S. companies. Investing in securities of foreign companies subjects the Fund to the risks associated with an issuer’s (and any of its related companies’) country of organization and places of business operations, including risks related to political, regulatory, economic, social, diplomatic and other conditions or events (including, for example, military confrontations and actions, war, other conflicts, terrorism and disease/virus outbreaks and epidemics) occurring in the country or region, as well as risks associated with less developed custody and settlement practices. Foreign securities may be more volatile and less liquid than securities of U.S. companies, and are subject to the risks associated with potential imposition of economic and other sanctions against a particular foreign country, its nationals or industries or businesses within the country. In addition, foreign governments may impose withholding or other taxes on the Fund’s income, capital gains or proceeds from the disposition of foreign securities, which could reduce the Fund’s return on such securities. 

Operational and Settlement Risks of Foreign Securities. The Fund’s foreign securities are generally held outside the United States in the primary market for the securities in the custody of foreign sub-custodians. Some countries have limited governmental oversight and regulation, which increases the risk of corruption and fraud and the possibility of losses to the Fund. In particular, under certain circumstances, foreign securities may settle on a delayed delivery basis, meaning that the Fund may be required to make payment for securities before the Fund has actually received delivery of the securities or deliver securities prior to the receipt of payment. As a result, there is a risk that the security will not be delivered to the Fund or that payment will not be received. Losses can also result from lost, stolen or counterfeit securities; defaults by brokers and banks; failures or defects of the settlement system; or poor and improper record keeping by registrars and issuers. 

Share Blocking. In certain non-U.S. markets, an issuer’s securities are blocked from trading for a specified number of days before and, in certain instances, after a shareholder meeting. The blocking period can last up to several weeks. Share blocking may prevent the Fund from buying or selling securities during this period. As a consequence of these restrictions, the Investment Manager, on behalf of the Fund, may abstain from voting proxies in markets that require share blocking. 

Emerging Market Securities Risk. Securities issued by foreign governments or companies in emerging market countries are more likely to have greater exposure to the risks of investing in foreign securities that are described in Foreign Securities Risk. In addition, emerging market countries are more likely to experience instability resulting, for example, from rapid changes or developments in social, political, economic or other conditions. Their economies are 

Prospectus 2022 7

Columbia Acorn USA®

Summary of the Fund (continued)

usually less mature and their securities markets are typically less developed with more limited trading activity (i.e., lower trading volumes and less liquidity) than more developed countries. Emerging market securities tend to be more volatile, and may be more susceptible to market manipulation, than securities in more developed markets. Many emerging market countries are heavily dependent on international trade and have fewer trading partners, which makes them more sensitive to world commodity prices and economic downturns in other countries, and some have a higher risk of currency devaluations. Due to the differences in the nature and quality of financial information of issuers of emerging market securities, including auditing and financial reporting standards, financial information and disclosures about such issuers may be unavailable or, if made available, may be considerably less reliable than publicly available information about other foreign securities. 

Frequent Trading Risk. In connection with the repositioning of the Fund’s portfolio to align with the May 1, 2022 increase in the market capitalization of the companies in which the Fund may invest, the portfolio managers may more actively and frequently trade investments in the Fund's portfolio to carry out its investment strategies than they would absent the repositioning. Frequent trading of investments increases the possibility that the Fund, as relevant, will realize taxable capital gains (including short-term capital gains, which are generally taxable to shareholders at higher rates than long-term capital gains for U.S. federal income tax purposes), which could reduce the Fund's after-tax return. Frequent trading can also mean higher brokerage and other transaction costs, which could reduce the Fund's return. The trading costs and tax effects associated with portfolio turnover may adversely affect the Fund’s performance. 

Performance Information

The following bar chart and table show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. The bar chart shows how the Fund’s Class Inst share performance has varied for each full calendar year shown. The table below the bar chart compares the Fund’s returns for the periods shown with the Russell 2500 Growth Index.

Effective May 1, 2022, the Fund compares its performance to that of the Russell 2500 Growth Index (the New Index). Prior to this date, the Fund compared its performance to that of the Russell 2000 Growth Index (the Former Index). The Fund changed its primary benchmark in connection with changes to its principal investment strategies that became effective May 1, 2022. The Investment Manager believes that the New Index provides a more appropriate comparison than the Former Index for investors measuring the Fund's relative performance. Information on the Former Index will be shown for a one-year transition period. 

The performance of one or more share classes shown in the Average Annual Total Returns table below includes the Fund’s Class Inst share returns (adjusted to reflect the higher class-related operating expenses of such classes, where applicable) for periods prior to the indicated inception date of such share classes. Except for differences in fees and expenses, all share classes of the Fund would have substantially similar annual returns because all share classes of the Fund invest in the same portfolio of securities. 

The after-tax returns shown in the Average Annual Total Returns table below are calculated using the highest historical individual U.S. federal marginal income tax rates in effect during the period indicated in the table and do not reflect the impact of state, local or foreign taxes. Your actual after-tax returns will depend on your personal tax situation and may differ from those shown in the table. In addition, the after-tax returns shown in the table do not apply to shares held in tax-advantaged accounts such as 401(k) plans or Individual Retirement Accounts (IRAs). The after-tax returns are shown only for Class Inst shares and will vary for other share classes. Returns after taxes on distributions and sale of Fund shares are higher than before-tax returns for certain periods shown because they reflect the tax benefit of capital losses realized on the redemption of Fund shares. 

The Fund’s performance prior to May 1, 2022 reflects returns achieved pursuant to a strategy with a different market capitalization limit on the companies in which the Fund invests a majority of its assets. If the Fund's current strategies had been in place for the prior periods, results shown would have been different. 

8 Prospectus 2022

Columbia Acorn USA®

Summary of the Fund (continued)

The Fund’s past performance (before and after taxes) is no guarantee of how the Fund will perform in the future. Updated performance information can be obtained by calling toll-free 800.345.6611 or visiting columbiathreadneedleus.com. 

Year by Year Total Return (%) as of December 31 Each Year*	Best and Worst Quarterly Returns During the Period Shown in the Bar Chart
	Best	2nd Quarter 2020	26.69%
	Worst	1st Quarter 2020	-27.03%

* Year to Date return as of March 31, 2022: -16.59%

 Average Annual Total Returns After Applicable Sales Charges (for periods ended December 31, 2021)

	Share Class Inception Date	1 Year	5 Years	10 Years
Class Inst	09/04/1996
returns before taxes		8.95%	15.74%	14.24%
returns after taxes on distributions		2.33%	11.04%	9.41%
returns after taxes on distributions and sale of Fund shares		9.25%	11.47%	10.27%
Class A returns before taxes	10/16/2000	2.48%	14.11%	13.29%
Class Adv returns before taxes	11/08/2012	8.92%	15.75%	14.25%
Class C returns before taxes	10/16/2000	7.02%	14.59%	13.14%
Class Inst2 returns before taxes	11/08/2012	8.99%	15.83%	14.33%
Class Inst3 returns before taxes	11/08/2012	9.09%	15.88%	14.38%
Russell 2500 Growth Index (reflects no deductions for fees, expenses or taxes)		5.04%	17.65%	15.75%
Russell 2000 Growth Index (reflects no deductions for fees, expenses or taxes)		2.83%	14.53%	14.14%

Fund Management

Investment Manager: Columbia Wanger Asset Management, LLC

Portfolio Management	Title	Role with Fund	Service with the Fund Since
Daniel Cole, CFA	Senior Portfolio Manager of Columbia Management Investment Advisers, LLC and Vice President of the Investment Manager	Co-Portfolio Manager since May 2022	2021
Erika K. Maschmeyer, CFA	Director of Research (U.S.), Portfolio Manager and Analyst at the Investment Manager	Co-Portfolio Manager since 2021	2016
John L. Emerson, CFA	Portfolio Manager and Analyst at the Investment Manager	Co-Portfolio Manager since 2021	2003

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Summary of the Fund (continued)

Purchase and Sale of Fund Shares

You may purchase or redeem shares of the Fund on any business day by contacting the Fund in the ways described below:

Online	Regular Mail	Express Mail	By Telephone
columbiathreadneedleus.com/investor/	Columbia Management Investment Services Corp. P.O. Box 219104 Kansas City, MO 64121-9104	Columbia Management Investment Services Corp. c/o DST Asset Manager Solutions, Inc. 430 W 7th Street, Suite 219104 Kansas City, MO 64105-1407	800.422.3737

You may purchase shares and receive redemption proceeds by electronic funds transfer, by check or by wire. If you maintain your account with a broker-dealer or other financial intermediary, you must contact that financial intermediary to buy, sell or exchange shares of the Fund through your account with the intermediary.

The minimum initial investment amounts for the share classes offered by the Fund are shown below:

Minimum Initial Investment

Class	Category of eligible account	For accounts other than Systematic Investment Plan accounts (as described in the Fund’s Prospectus)	For Systematic Investment Plan accounts
Classes A & C	All accounts other than IRAs	$2,000	$100
	IRAs	$1,000	$100
Classes Adv & Inst	All eligible accounts	$0, $1,000 or $2,000 depending upon the category of eligible investor	$100
Class Inst2	All eligible accounts	None	N/A
Class Inst3	All eligible accounts	$0, $1,000, $2,000 or $1 million depending upon the category of eligible investor	$100 (for certain eligible investors)

More information about these minimums can be found in the Buying, Selling and Exchanging Shares - Buying Shares section of the prospectus. There is no minimum additional investment for any share class.

Tax Information

The Fund normally distributes net investment income and net realized capital gains, if any, to shareholders. These distributions are generally taxable to you as ordinary income, qualified dividend income or capital gains, unless you are investing through a tax-advantaged account, such as a 401(k) plan or an IRA. If you are investing through a tax-advantaged account, you may be taxed upon withdrawals from that account.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase the Fund through a broker-dealer or other financial intermediary (such as a bank), the Fund and its related companies – including the Investment Manager, the Distributor and Columbia Management Investment Services Corp. (the Transfer Agent) – may pay the intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your financial advisor to recommend the Fund over another investment. These potential conflicts of interest may be heightened with respect to broker-dealers owned by Ameriprise Financial, Inc. (Ameriprise Financial) and/or its affiliates. Ask your financial advisor or visit your financial intermediary's website for more information.

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Investment Objective

Columbia Acorn USA® (the Fund) seeks long-term capital appreciation. The Fund’s investment objective is not a fundamental policy of the Fund and may be changed by the Fund’s Board of Trustees (the Board) without shareholder approval. There is no assurance the Fund’s objective will be achieved.

Principal Investment Strategies

Under normal circumstances, the Fund invests at least 80% of its net assets (including the amount of any borrowings for investment purposes) in U.S. companies.

Under normal circumstances, the Fund invests a majority of its net assets in the common stock of small- and mid-sized companies with market capitalizations generally in the range of market capitalizations in the Russell 2500 Growth Index, the Fund's benchmark, (the Index) at the time of purchase (between $21.5 million and $30 billion as of March 31, 2022). The market capitalization range and composition of companies in the Index are subject to change. As such, the size of the companies in which the Fund invests may change. The Fund determines a company’s market capitalization at the time of investment. As long as a majority of its net assets are invested in companies within the Index, the Fund may continue to hold and make new investments in a security even if the company’s market capitalization grows beyond the market capitalization of the largest company within the Index or falls below the market capitalization of the smallest company within the Index.

Columbia Wanger Asset Management, LLC, the Fund's investment adviser (the Investment Manager), believes that stocks of small- and mid-sized companies, which generally are not as well known by financial analysts as larger companies, may offer higher return potential than stocks of larger companies. The Fund invests the majority of its assets in U.S. companies, but also may invest up to 20% of its total assets in foreign companies in developed markets (for example, Japan, Canada and the United Kingdom) and in emerging markets (for example, China, India and Brazil). The Investment Manager from time to time emphasizes one or more sectors in selecting the Fund’s investments, including the consumer discretionary, health care, and information technology sectors.

The Investment Manager typically seeks companies with:

■ A strong business franchise that offers growth potential.

■ Products and services in which the company has a competitive advantage.

■ A stock price the Investment Manager believes is reasonable relative to the assets and earning power of the company.

The Investment Manager may sell a portfolio holding if the security reaches the Investment Manager's price target, if the company has a deterioration of fundamentals, such as failing to meet key operating benchmarks, or if the Investment Manager believes other securities are more attractive. The Investment Manager also may sell a portfolio holding to fund redemptions.

Principal Risks

An investment in the Fund involves risks, including those described below, among others. There is no assurance that the Fund will achieve its investment objective and you may lose money. The value of the Fund’s holdings may decline, and the Fund’s net asset value (NAV) and share price may go down. An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Active Management Risk. The Fund is actively managed and its performance therefore will reflect, in part, the ability of the Investment Manager to select investments and to make investment decisions that will achieve the Fund’s investment objective. The Investment Manager’s active management of the Fund could cause the Fund to underperform its benchmark index and/or other funds with similar investment objectives and/or strategies.

Small- and Mid-Cap Company Securities Risk. Securities of small- and mid-cap companies can, in certain circumstances, have a higher potential for gains than securities of larger, more established companies but may also have more risk. For example, small- and mid-cap companies may be more vulnerable to market downturns and adverse business or economic events than larger companies because they may have more limited financial resources

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and business operations. Small- and mid-cap companies are also more likely than larger companies to have more limited product lines and operating histories and to depend on smaller and generally less experienced management teams. Securities of small- and mid-cap companies may trade less frequently and in smaller volumes and may be less liquid and fluctuate more sharply in value than securities of larger companies. When the Fund takes significant positions in small- and mid-cap companies with limited trading volumes, the liquidation of those positions, particularly in a distressed market, could be prolonged and result in Fund investment losses that would affect the value of your investment in the Fund. In addition, some small- and mid-cap companies may not be widely followed by the investment community, which can lower the demand for their stocks.

Market Risk. The Fund may incur losses due to declines in the value of one or more securities in which it invests. These declines may be due to factors affecting a particular issuer, or the result of, among other things, political, regulatory, market, economic or social developments affecting the relevant market(s) more generally. In addition, turbulence in financial markets and reduced liquidity in equity, credit and/or fixed income markets may negatively affect many issuers, which could adversely affect the Fund’s ability to price or value hard-to-value assets in thinly traded and closed markets and could cause significant redemptions and operational challenges. Global economies and financial markets are increasingly interconnected, and conditions and events in one country, region or financial market may adversely impact issuers in a different country, region or financial market. These risks may be magnified if certain events or developments adversely interrupt the global supply chain; in these and other circumstances, such risks might affect companies worldwide. As a result, local, regional or global events such as terrorism, war, other conflicts, natural disasters, disease/virus outbreaks and epidemics or other public health issues, recessions, depressions or other events – or the potential for such events – could have a significant negative impact on global economic and market conditions.

The large-scale invasion of Ukraine by Russia in February 2022 has resulted in sanctions and market disruptions including declines in regional and global stock and commodity markets and significant devaluations of Russian currency. The extent and duration of the military action are impossible to predict but could be significant. Market disruption caused by the Russian military action, and any counter measures or responses thereto (including international sanctions, a downgrade in the country’s credit rating, purchasing and financing restrictions, boycotts, tariffs, changes in consumer or purchaser preferences, cyberattacks and espionage) could have severe adverse impacts on regional and/or global securities and commodities markets, including markets for oil and natural gas. These impacts may include reduced market liquidity, distress in credit markets, further disruption of global supply chains, increased risk of inflation, and limited access to investments in certain international markets and/or issuers. These developments and other related events could negatively impact Fund performance.

The pandemic caused by coronavirus disease 2019 and its variants (COVID-19) has resulted in, and may continue to result in, significant global economic and societal disruption and market volatility due to disruptions in market access, resource availability, facilities operations, imposition of tariffs, export controls and supply chain disruption, among others. Such disruptions may be caused, or exacerbated by, quarantines and travel restrictions, workforce displacement and loss in human and other resources. The uncertainty surrounding the magnitude, duration, reach, costs and effects of the global pandemic, as well as actions that have been or could be taken by governmental authorities or other third parties, present unknowns that are yet to unfold. The impacts, as well as the uncertainty over impacts to come, of COVID-19 – and any other infectious illness outbreaks, epidemics and pandemics that may arise in the future – could negatively affect global economies and markets in ways that cannot necessarily be foreseen. In addition, the impact of infectious illness outbreaks and epidemics in less developed countries may be greater due to generally less established healthcare systems, governments and financial markets. Public health crises caused by the COVID-19 outbreak may exacerbate other pre-existing political, social and economic risks in certain countries or globally. The disruptions caused by COVID-19 could prevent the Fund from executing advantageous investment decisions in a timely manner and negatively impact the Fund’s ability to achieve its investment objective. Any such events could have a significant adverse impact on the value and risk profile of the Fund.

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Issuer Risk. An issuer in which the Fund invests may perform poorly, and the value of its securities may therefore decline, which may negatively affect the Fund’s performance. Underperformance of an issuer may be caused by poor management decisions, competitive pressures, breakthroughs in technology, reliance on suppliers, labor problems or shortages, corporate restructurings, fraudulent disclosures, natural disasters, military confrontations and actions, war, terrorism, disease/virus outbreaks and epidemics or other events, conditions and factors.

Growth Securities Risk. Growth securities typically trade at a higher multiple of earnings than other types of equity securities. Accordingly, the market values of growth securities may never reach their expected market value and may decline in price. In addition, growth securities, at times, may not perform as well as value securities or the stock market in general, and may be out of favor with investors for varying periods of time.

Liquidity and Trading Volume Risk. Because the Fund may invest a percentage of its assets in foreign securities, including in emerging markets, it may be subject to the liquidity and trading volume risks associated with international investing, including in emerging markets. Due to market conditions, including uncertainty regarding the price of a security, it may be difficult for the Fund to buy or sell foreign portfolio securities at a desirable time or price, which could result in investment losses and may affect the value of your investment in the Fund. This risk of portfolio illiquidity is heightened with respect to small- and mid-cap securities, generally, and foreign small- and mid-cap securities in particular. The Fund may have to lower the selling price, liquidate other investments, or forego another, more appealing investment opportunity as a result of illiquidity in the markets. The Investment Manager will fair value in good faith any securities it deems to be illiquid under consistently applied procedures established by the Fund’s Board. Market conditions are always changing and vary by country and industry sector, and investing in international markets involves unique risks. Although it is difficult to accurately assess trends in trading volumes in foreign markets, a reduction in trading volumes poses challenges to the Fund. This is particularly so because the Fund focuses on small- and mid-cap companies that usually have lower trading volumes and often takes sizeable positions in portfolio companies. As a result of lower trading volumes, it may take longer to buy or sell these securities, which can exacerbate the Fund’s exposure to volatile markets. The Fund may also be limited in its ability to execute favorable trades in foreign portfolio securities in response to changes in share prices and fundamentals. If the Fund is forced to sell securities to meet redemption requests or other cash needs, or in the case of an event affecting liquidity in a particular market or markets, it may be forced to dispose of those securities under disadvantageous circumstances and at a loss. As the Fund grows in size or, conversely, if it faces significant redemption pressure, these considerations take on increasing significance and may adversely impact performance.

Sector Risk. At times, the Fund may have a significant portion of its assets invested in securities of companies conducting business within one or more economic sectors, including the consumer discretionary, health care, and information technology sectors. Companies in the same sector may be similarly affected by economic, regulatory, political or market events or conditions, which may make the Fund more vulnerable to unfavorable developments in that sector than funds that invest more broadly. Generally, the more broadly the Fund invests, the more it spreads risk and potentially reduces the risks of loss and volatility.

■ Consumer Discretionary Sector. The Fund is more susceptible to the particular risks that may affect companies in the consumer discretionary sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the consumer discretionary sector are subject to certain risks, including fluctuations in the performance of the overall domestic and international economy, interest rate changes, increased competition and consumer confidence. Performance of such companies may be affected by factors including reduced disposable household income, reduced consumer spending, and changing demographics and consumer tastes.

■ Health Care Sector. The Fund is more susceptible to the particular risks that may affect companies in the health care sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the health care sector are subject to certain risks, including restrictions on government reimbursement for medical expenses, government approval of medical products and services, competitive pricing pressures, and the rising cost of medical products and services (especially for companies dependent upon a relatively limited number of products or services), among others. Performance of such companies may be affected by factors including, government regulation, obtaining and protecting patents (or the failure to do so), product liability and other similar litigation as well as product obsolescence.

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■ Information Technology Sector. The Fund is more susceptible to the particular risks that may affect companies in the information technology sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the information technology sector are subject to certain risks, including the risk that new services, equipment or technologies will not be accepted by consumers and businesses or will become rapidly obsolete. Performance of such companies may be affected by factors including obtaining and protecting patents (or the failure to do so) and significant competitive pressures, including aggressive pricing of their products or services, new market entrants, competition for market share and short product cycles due to an accelerated rate of technological developments. Such competitive pressures may lead to limited earnings and/or falling profit margins. As a result, the value of their securities may fall or fail to rise. In addition, many information technology sector companies have limited operating histories and prices of these companies’ securities historically have been more volatile than other securities, especially over the short term. Some companies in the information technology sector are facing increased government and regulatory scrutiny and may be subject to adverse government or regulatory action, which could negatively impact the value of their securities.

Foreign Securities Risk. Investments in or exposure to securities of foreign companies may involve heightened risks relative to investments in or exposure to securities of U.S. companies. For example, foreign markets can be extremely volatile. Foreign securities may also be less liquid, making them more difficult to trade, than securities of U.S. companies so that the Fund may, at times, be unable to sell foreign securities at desirable times or prices. Brokerage commissions, custodial costs and other fees are also generally higher for foreign securities. The Fund may have limited or no legal recourse in the event of default with respect to certain foreign securities, including those issued by foreign governments. In addition, foreign governments may impose withholding or other taxes on the Fund’s income, capital gains or proceeds from the disposition of foreign securities, which could reduce the Fund’s return on such securities. In some cases, such withholding or other taxes could potentially be confiscatory. Other risks include: possible delays in the settlement of transactions or in the payment of income; generally less publicly available information about foreign companies; the impact of economic, political, social, diplomatic or other conditions or events (including, for example, military confrontations and actions, war, other conflicts, terrorism and disease/virus outbreaks and epidemics), possible seizure, expropriation or nationalization of a company or its assets or the assets of a particular investor or category of investors; accounting, auditing and financial reporting standards that may be less comprehensive and stringent than those applicable to domestic companies; the imposition of economic and other sanctions against a particular foreign country, its nationals or industries or businesses within the country; and the generally less stringent standard of care to which local agents may be held in the local markets. In addition, it may be difficult to obtain reliable information about the securities and business operations of certain foreign issuers. Governments or trade groups may compel local agents to hold securities in designated depositories that are not subject to independent evaluation. The less developed a country’s securities market is, the greater the level of risks. Economic sanctions may be, and have been, imposed against certain countries, organizations, companies, entities and/or individuals. Economic sanctions and other similar governmental actions could, among other things, effectively restrict or eliminate the Fund’s ability to purchase or sell securities, and thus may make the Fund’s investments in such securities less liquid or more difficult to value. In addition, as a result of economic sanctions, the Fund may be forced to sell or otherwise dispose of investments at inopportune times or prices, which could result in losses to the Fund and increased transaction costs. These conditions may be in place for a substantial period of time and enacted with limited advance notice to the Fund. The risks posed by sanctions against a particular foreign country, its nationals or industries or businesses within the country may be heightened to the extent the Fund invests significantly in the affected country or region or in issuers from the affected country that depend on global markets. Additionally, investments in certain countries may subject the Fund to a number of tax rules, the application of which may be uncertain. Countries may amend or revise their existing tax laws, regulations and/or procedures in the future, possibly with retroactive effect. Changes in or uncertainties regarding the laws, regulations or procedures of a country could reduce the after-tax profits of the Fund, directly or indirectly, including by reducing the after-tax profits of companies located in such countries in which the Fund invests, or result in unexpected tax liabilities for the Fund.

Operational and Settlement Risks of Foreign Securities. The Fund’s foreign securities are generally held outside the United States in the primary market for the securities in the custody of certain eligible foreign banks and trust companies (“foreign sub-custodians”), as permitted under the Investment Company Act of 1940 (the 1940 Act). Settlement practices for foreign securities may differ from those in the United States. Some countries have limited

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governmental oversight and regulation of industry practices, stock exchanges, depositories, registrars, brokers and listed companies, which increases the risk of corruption and fraud and the possibility of losses to the Fund. In particular, under certain circumstances, foreign securities may settle on a delayed delivery basis, meaning that the Fund may be required to make payment for securities before the Fund has actually received delivery of the securities or deliver securities prior to the receipt of payment. Typically, in these cases, the Fund will receive evidence of ownership in accordance with the generally accepted settlement practices in the local market entitling the Fund to delivery or payment at a future date, but there is a risk that the security will not be delivered to the Fund or that payment will not be received, although the Fund and its foreign sub-custodians take reasonable precautions to mitigate this risk. Losses can also result from lost, stolen or counterfeit securities; defaults by brokers and banks; failures or defects of the settlement system; or poor and improper record keeping by registrars and issuers.

Share Blocking. Share blocking refers to a practice in certain foreign markets under which an issuer’s securities are blocked from trading at the custodian or sub-custodian level for a specified number of days before and, in certain instances, after a shareholder meeting where a vote of shareholders takes place. The blocking period can last up to several weeks. Share blocking may prevent the Fund from buying or selling securities during this period, because during the time shares are blocked, trades in such securities will not settle. It may be difficult or impossible to lift blocking restrictions, with the particular requirements varying widely by country. As a consequence of these restrictions, the Investment Manager, on behalf of the Fund, may abstain from voting proxies in markets that require share blocking.

Emerging Market Securities Risk. Securities issued by foreign governments or companies in emerging market countries are more likely to have greater exposure to the risks of investing in foreign securities that are described in Foreign Securities Risk. In addition, emerging market countries are more likely to experience instability resulting, for example, from rapid changes or developments in social, political, economic or other conditions. Their economies are usually less mature and their securities markets are typically less developed with more limited trading activity (i.e., lower trading volumes and less liquidity) than more developed countries. Emerging market securities tend to be more volatile, and may be more susceptible to market manipulation, than securities in more developed markets. Many emerging market countries are heavily dependent on international trade and have fewer trading partners, which makes them more sensitive to world commodity prices and economic downturns in other countries. Some emerging market countries have a higher risk of currency devaluations, and some of these countries may experience periods of high inflation or rapid changes in inflation rates and may have hostile relations with other countries. Due to the differences in the nature and quality of financial information of issuers of emerging market securities, including auditing and financial reporting standards, financial information and disclosures about such issuers may be unavailable or, if made available, may be considerably less reliable than publicly available information about other foreign securities.

Frequent Trading Risk. In connection with the repositioning of the Fund’s portfolio to align with the May 1, 2022 increase in the market capitalization of the companies in which the Fund may invest, the portfolio managers may more actively and frequently trade investments in the Fund's portfolio to carry out its investment strategies than they would absent the repositioning. Frequent trading of investments increases the possibility that the Fund, as relevant, will realize taxable capital gains (including short-term capital gains, which are generally taxable to shareholders at higher rates than long-term capital gains for U.S. federal income tax purposes), which could reduce the Fund's after-tax return. Frequent trading can also mean higher brokerage and other transaction costs, which could reduce the Fund's return. The trading costs and tax effects associated with portfolio turnover may adversely affect the Fund’s performance.

Additional Investment Strategies and Policies

This section describes certain investment strategies and policies that the Fund may utilize in pursuit of its investment objective and some additional factors and risks involved with investing in the Fund. For information about risks associated with changing levels of Fund distributions, see the SAI.

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Changing the Fund’s Investment Objective and Policies

The Fund’s investment objective and non-fundamental investment policies (including its principal and additional investment strategies) can be changed by the Board without shareholder approval, but may require notice to shareholders in certain instances. The Fund’s fundamental investment policies, as identified in the Fund’s Statement of Additional Information (SAI), may be changed only with Board and shareholder approval in accordance with the voting requirements of the 1940 Act. For additional information about changing the Fund’s fundamental and non-fundamental investment policies, see the SAI.

Investment Guidelines

As a general matter, and except as specifically described in the discussion of the Fund's principal investment strategies in this prospectus, whenever an investment policy or limitation states a percentage of the Fund's assets that may be invested in any security or other asset or sets forth a policy regarding an investment standard, compliance with that percentage limitation or standard will be determined based on the characteristics of a company at the time of initial purchase, and subsequent changes in a characteristic are not taken into account.

Holding Other Kinds of Investments

The Fund may hold other investments that are not part of its principal investment strategies. These investments and their risks are described below and/or in the SAI. The Fund may choose not to invest in certain securities described in this prospectus and in the SAI, although it has the ability to do so. Information on the Fund’s holdings can be found in the Fund’s shareholder reports or by visiting columbiathreadneedleus.com.

Transactions in Derivatives

The Fund may enter into derivative transactions or otherwise have exposure to derivative transactions through underlying investments. The Fund expects to enter into such transactions primarily in the form of stock index futures in order to obtain exposure to the overall sector of the market represented by a particular stock index or to invest the Fund’s uninvested cash balances in a manner that the Investment Manager believes aligns more closely with the Fund’s investment strategy than simply holding short-term fixed income investments or cash equivalents (known as cash equitization). Derivatives are financial contracts whose values are, for example, based on (or “derived” from) traditional securities (such as a stock or bond), assets (such as a commodity like gold or a foreign currency), reference rates (such as the Secured Overnight Financing Rate (commonly known as SOFR) or the London Interbank Offered Rate (commonly known as LIBOR)) or market indices (such as the Standard & Poor's (S&P) 500^® Index). The use of derivatives is a highly specialized activity which involves investment techniques and risks different from those associated with ordinary portfolio securities transactions. Derivatives involve special risks and may result in losses or may limit the Fund's potential gain from favorable market movements. Derivative strategies typically expose the Fund to gains and losses in excess of the amount actually invested in the derivative. This characteristic of a derivative (known as "leverage") may exaggerate a loss, potentially causing the Fund to lose more money than it would have lost had it invested in the underlying security or other asset directly. The values of derivatives may move in unexpected ways, especially in unusual (including distressed) market conditions, and may result in increased volatility in the value of the derivative and/or the Fund’s shares, among other consequences. The use of derivatives may also increase the amount of taxes payable by shareholders holding shares in a taxable account. Other risks arise from the Fund's potential inability to terminate or to sell derivative positions. A liquid secondary market may not always exist for the Fund's derivative positions at times when the Fund might wish to terminate or to sell such positions. Over-the-counter instruments (investments not traded on an exchange) may be illiquid, and transactions in derivatives traded in the over-the-counter market are subject to the risk that the other party will not meet its obligations. The use of derivatives also involves the risks of mispricing or improper valuation and that changes in the value of the derivative may not correlate perfectly with the underlying security, asset, reference rate or index. The Fund also may not be able to find a suitable derivative transaction counterparty, and thus may be unable to engage in derivative transactions when it is deemed favorable to do so, or at all. U.S. federal legislation has been enacted that provides for new clearing, margin, reporting and registration requirements for participants in the derivatives market. These changes could restrict and/or impose significant costs or other burdens upon the Fund’s participation in derivatives transactions. The U.S. government and the European Union (and some other jurisdictions) have enacted

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regulations and similar requirements that prescribe clearing, margin, reporting and registration requirements for participants in the derivatives market. These requirements are evolving and their ultimate impact on the Fund remains unclear but such impact could include restricting and/or imposing significant costs or other burdens upon the Fund’s participation in derivatives transactions. Additionally, in October 2020, the SEC adopted new regulations governing the use of derivatives by registered investment companies. Once effective, Rule 18f-4 will, among other things, require funds that invest in derivative instruments beyond a specified limited amount to apply a value-at-risk based limit to their use of certain derivative instruments and establish a comprehensive derivatives risk management program. A fund that uses derivative instruments in a limited amount will not be subject to the full requirements of Rule 18f-4. Compliance with Rule 18f-4 will not be required until August 2022. Rule 18f-4 could have an adverse impact on the Fund’s performance and ability to implement its investment strategies as it has historically. For more information on the risks of derivative investments and strategies, see the SAI.

LIBOR Phase-Out Risk. Many derivatives and other financial instruments utilize or are permitted to utilize a floating interest rate based on LIBOR. On July 27, 2017, the United Kingdom's Financial Conduct Authority (FCA) announced its intention to phase out the use of LIBOR by the end of 2021. The FCA and the ICE Benchmark Administration have since announced that a majority of U.S. dollar LIBOR settings will cease publication after June 30, 2023. A subset of non-U.S. dollar LIBOR settings are continuing to be published on a “synthetic” basis and it is possible that a subset of U.S. dollar LIBOR settings will also be published after June 30, 2023 on a “synthetic” basis. Any such publications are, or would be considered, non-representative of the underlying market. Uncertainty related to the liquidity impact of changes in reference rates, and how to appropriately adjust these rates at the time of transition, poses risks for the Fund. It is difficult to predict the full impact of the transition away from LIBOR on the Fund until new reference rates and fallbacks for both legacy and new products, instruments and contracts are commercially accepted and market practices become more settled. The Investment Manager monitors the Fund's LIBOR exposure risks, including the extent to which any derivative and/or debt investments allow for the utilization of alternative rate(s), such as the Secured Overnight Financing Rate (SOFR), which the U.S. Federal Reserve is promoting as the alternative reference rate to LIBOR.

Affiliated Fund Investing

The Investment Manager and its affiliate, Columbia Management Investment Advisers, LLC (Columbia Management), each serves as investment adviser to mutual funds and ETFs using the Columbia brand (Columbia Funds), including mutual funds that are structured as “fund-of-funds”, and provides asset-allocation services to (i) shareholders by investing in shares of other Columbia Funds, which may include the Fund (collectively referred to in this section as Underlying Funds), and (ii) discretionary managed accounts (collectively referred to as affiliated products) that invest exclusively in Underlying Funds. These affiliated products, individually or collectively, may own a significant percentage of the outstanding shares of one or more Underlying Funds, and the Investment Manager and Columbia Management seek to balance potential conflicts of interest between the affiliated products and the Underlying Funds in which they invest. The affiliated products’ investment in the Underlying Funds may have the effect of creating economies of scale, possibly resulting in lower expense ratios for the Underlying Funds, because the affiliated products may own substantial portions of the shares of Underlying Funds. However, redemption of Underlying Fund shares by one or more affiliated products could cause the expense ratio of the Underlying Fund to increase, as its fixed costs would be spread over a smaller asset base. Because of large positions of certain affiliated products, the Underlying Funds may experience relatively large inflows and outflows of cash due to affiliated products’ purchases and sales of Underlying Fund shares. Although the Investment Manager or Columbia Management may seek to minimize the impact of these transactions where possible, for example, by structuring them over a reasonable period of time or through other measures, Underlying Funds may experience increased expenses as they buy and sell portfolio securities to manage the cash flow effect related to these transactions. Further, when the Investment Manager or Columbia Management structures transactions over a reasonable period of time in order to manage the potential impact of the buy and sell decisions for the affiliated products, those affiliated products, including funds-of-funds, may pay more or less (for purchase activity), or receive more or less (for redemption activity), for shares of the Underlying Funds than if the transactions were executed in one transaction. In addition, substantial redemptions by affiliated products within a short period of time could require the Underlying Fund to liquidate positions more rapidly than would otherwise be desirable, which may have the effect of reducing or eliminating potential gain or causing it to

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realize a loss. In order to meet such redemptions, the Underlying Fund may be forced to sell its liquid (or more liquid) positions, leaving the Underlying Fund holding, post-redemption, a relatively larger position in illiquid investments (i.e., any investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without the sale or disposition significantly changing the market value of the investment) or less liquid securities. Substantial redemptions may also adversely affect the ability of the Underlying Fund to implement its investment strategy. The Investment Manager or Columbia Management also has a conflict of interest in determining the allocation of affiliated products’ assets among the Underlying Funds, as it earns different fees from the various Underlying Funds.

Investing in Money Market Funds

The Fund may invest cash, including cash collateral received in connection with its securities lending program, in shares of money market funds, including funds advised by affiliates of the Investment Manager. These funds are not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency. The Fund and its shareholders indirectly bear a portion of the expenses of any money market fund or other fund in which the Fund may invest.

Lending of Portfolio Securities

The Fund may lend portfolio securities to broker-dealers or other financial intermediaries on a fully collateralized basis in order to earn additional income. The Fund may lose money from securities lending if, for example, the borrower does not return a loaned security and the proceeds from sale of the collateral are not sufficient to replace the borrowed security. The Fund invests collateral in a government money market fund.

Investing Defensively

The Fund may from time to time take temporary defensive investment positions that are inconsistent with the Fund’s principal investment strategies in attempting to respond to adverse market, economic, political, social or other conditions. These investment positions may include, without limitation, investing some or all of its assets in money market instruments or shares of affiliated or unaffiliated money market funds or holding some or all of its assets in cash or cash equivalents. The Fund may take such defensive positions for as long a period as the Investment Manager deems necessary. During these times, the Investment Manager may make frequent portfolio changes, which could result in increased trading expenses and taxes, and decreased Fund performance.

Portfolio Holdings Disclosure

A description of the Fund’s policies and procedures with respect to the disclosure of Fund portfolio securities is available in the SAI. The Fund discloses its portfolio holdings on the Columbia Funds’ website, columbiathreadneedleus.com, as described below. Once posted, the portfolio holdings information will remain available on the website until at least the date on which such Fund files a Form N-CSR or publicly available Form N-PORT (forms filed with the SEC that include portfolio holdings information) for the period that includes the date as of which the information is current.

The Fund considers changes in its portfolio holdings to be confidential information. Consequently, Fund policy generally permits the disclosure of portfolio holdings information only after a certain amount of time has passed. The Fund’s complete portfolio holdings are disclosed approximately 30 to 40 days after each month-end. The top 15 holdings may be available sooner, approximately 15 calendar days after each month-end. Purchases and sales of portfolio securities can take place at any time, so the portfolio holdings information available on the website may not always be current.

Cybersecurity

The Fund, like all companies, may be susceptible to operational and information security risks, including the risk of cyber attacks or failures. As a result, the Fund or its service providers, or the issuers of securities in which the Fund invests, may experience disruptions in business operations that may potentially result in financial losses, the inability of the Fund or Fund shareholders to transact business, violations of applicable privacy and other laws, regulatory

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fines, penalties, reputational damage, reimbursement or other compensation costs, and/or additional compliance costs. The Fund and its shareholders could be negatively impacted as a result. See the discussion of Cybersecurity Breaches and Technology and Related Systems Failure Risk in the SAI for further information.

Use of Benchmarks

Benchmarks are indices that provide some comparative guidance in assessing the Fund’s performance. The Investment Manager selects the benchmarks it believes provide meaningful comparisons for each Fund. However, there may be different or additional indices that more closely reflect the market sectors in which the Fund invests. The Fund’s benchmarks may change from time to time. The benchmarks included in this prospectus are intended only as guideposts for your assessment of the Fund’s performance.

 FUNDamentals

Portfolio Holdings Versus the Benchmarks

The Fund does not limit its investments to the securities within its benchmarks, and accordingly the Fund's holdings may diverge significantly from those of the benchmarks selected by the Investment Manager. In addition, the Fund may invest in securities outside the industry and geographic sectors represented in its benchmarks. The Fund's weightings in individual securities, and in industry and geographic sectors, may also vary considerably from those of its benchmarks.

eDelivery and Mailings to Households

In order to reduce shareholder expenses, the Fund may mail only one copy of the Fund’s prospectus and each annual and semiannual report to those addresses shared by two or more accounts. If you wish to receive separate copies of these documents, call 800.345.6611 or, if your shares are held through a financial intermediary, contact your intermediary directly. Additionally, you may elect to enroll in eDelivery to receive electronic versions of these documents, as well as quarterly statements and supplements, by logging into your account at columbiathreadneedleus.com/investor/.

Additional Information on Portfolio Turnover

A mutual fund that replaces, or turns over, more than 100% of its investments in a year may be considered to have a high portfolio turnover rate. A high portfolio turnover rate can generate larger distributions of short-term capital gains to shareholders, which for individuals are generally taxable at higher rates than long-term capital gains for U.S. federal income tax purposes. Also, a high portfolio turnover rate can mean higher brokerage commissions and other transaction costs, which could reduce a fund’s returns. In general, the greater the volume of buying and selling by a fund, the greater the impact that brokerage commissions and other transaction costs will have on its returns. The Fund may sell securities regardless of how long they’ve been held. See the Financial Highlights section of this prospectus for the Fund's portfolio turnover rates for the past five years.

Cash Flows

The timing and magnitude of cash inflows from investors buying Fund shares could prevent the Fund from always being fully invested. Conversely, the timing and magnitude of cash outflows to shareholders redeeming Fund shares could require the Fund to sell portfolio securities at less than opportune times or to hold ready reserves of uninvested cash in amounts larger than might otherwise be the case to meet shareholder redemptions. Either situation could adversely impact the Fund’s performance.

Understanding Annual Fund Operating Expenses

The Fund’s annual operating expenses, as presented in the Annual Fund Operating Expenses table in the Fees and Expenses of the Fund section of this prospectus, generally are based on expenses incurred during the Fund’s most recently completed fiscal year, may vary by share class and are expressed as a percentage (expense ratio) of the Fund’s average net assets during that fiscal year. The expense ratios reflect the Fund’s fee arrangements as of the date of this prospectus and, unless indicated otherwise, are based on expenses incurred during the Fund’s most

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recent fiscal year. The Fund’s assets will fluctuate, but unless indicated otherwise in the Annual Fund Operating Expenses table, no adjustments have been or will be made to the expense ratios to reflect any differences in the Fund’s average net assets between the most recently completed fiscal year and the date of this prospectus or a later date. In general, the Fund’s expense ratios will increase as its net assets decrease, such that the Fund’s actual expense ratios may be higher than the expense ratios presented in the Annual Fund Operating Expenses table if assets fall. Any commitment by the Investment Manager and/or its affiliates to waive fees and/or cap (reimburse) expenses is expected, in part, to limit the impact of any increase in the Fund’s expense ratios that would otherwise result because of a decrease in the Fund’s assets in the current fiscal year. The Fund’s annual operating expenses are comprised of (i) investment management fees, (ii) distribution and/or service fees, and (iii) other expenses. Management fees do not vary by class, but distribution and/or service fees and other expenses may vary by class. Please see Fee Waiver/Expense Reimbursement Arrangements below for information about commitments made by the Investment Manager and/or its affiliates during the performance period covered by this prospectus.

 FUNDamentals

Other Expenses

“Other expenses” consist of the fees the Fund pays to its administrator, custodian, transfer agent, auditors, lawyers and trustees, costs relating to compliance and miscellaneous expenses. Generally, these expenses are allocated on a pro rata basis across all share classes. These expenses include certain sub-transfer agency and shareholder servicing fees. Transfer agency fees and certain shareholder servicing fees, however, are class specific. They differ by share class because the shareholder services provided to each share class may be different. Accordingly, the differences in “other expenses” among share classes are primarily the result of the different transfer agency and shareholder servicing fees applicable to each share class. For more information on these fees, see Choosing a Share Class — Financial Intermediary Compensation.

Fee Waiver/Expense Reimbursement Arrangements

The Investment Manager has contractually agreed to waive fees and reimburse certain expenses of the Fund through April 30, 2023, so that ordinary operating expenses (excluding transaction costs and certain other investment-related expenses, interest and fees on borrowings, and expenses associated with the Fund’s investment in other investment companies, if any) do not exceed the annual rates of:

Columbia Acorn USA
Class A	1.08%
Class Adv	0.83%
Class C	1.83%
Class Inst	0.83%
Class Inst2	0.81%
Class Inst3	0.76%

This arrangement may only be amended or terminated with approval from the Fund’s Board of Trustees and the Investment Manager.

In addition to the contractual agreement, the Investment Manager and certain of its affiliates have voluntarily agreed to waive fees and/or reimburse Fund expenses (other than the exclusions listed above) so that Fund level expenses (expenses directly attributable to the Fund and not to a specific share class) are waived proportionately across all share classes, but the Fund’s net operating expenses shall not exceed the contractual annual rates listed in the table above. This arrangement may be revised or discontinued at any time.

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The Transfer Agent has contractually agreed to waive a portion of the fees payable by the Fund such that through April 30, 2023, fees paid by the Fund to the Transfer Agent do not exceed the annual rate of 0.08% of the average daily net assets of each share class other than Class Inst2 and Class Inst3 shares of the Fund unless sooner terminated at the sole discretion of the Fund’s Board of Trustees.

Effect of Fee Waivers and/or Expense Reimbursements on Past Performance. The Fund’s returns shown in the Performance Information section of this prospectus reflect the effect of fee waivers and/or reimbursements of Fund expenses by the Investment Manager and/or its affiliates that were in place during the performance period shown in the Performance Information section of this prospectus. Without such fee waivers/expense reimbursements, the Fund’s returns might have been lower.

Board of Trustees

The Fund is governed by the Board. More than 75% of the Fund's Trustees are independent (Independent Trustees), meaning that they are not “interested persons” of the Fund, as defined in the 1940 Act. The Independent Trustees bring backgrounds in business and academia to their task of working with the Fund's officers to establish the Fund's policies and oversee its activities. Among the Trustees' responsibilities are: selecting the investment adviser for the Fund; approving the advisory agreement; reviewing other contracts; approving investment policies; monitoring Fund operations, performance, compliance and costs; and nominating or selecting new Trustees.

Each Trustee serves the Fund for an indefinite term until his or her retirement, resignation, death or removal in accordance with the organizational documents of Columbia Acorn Trust (the Trust). The Trust's Bylaws generally require that Trustees retire at the end of the calendar year in which they attain the age of 75 years. The last meeting to elect Trustees was held on February 27, 2015. Any Trustee may be removed at a shareholders' meeting by a vote representing two-thirds of the net asset value of all shares of the Columbia Acorn family of funds (Columbia Acorn Funds). The mailing address for the Trustees and officers is 71 S. Wacker Drive, Suite 2500, Chicago, Illinois 60606.

For more detailed information about the Board, please refer to the SAI.

Primary Service Provider Contracts

The Fund enters into contractual arrangements (Service Provider Contracts) with various parties, including, among others, the Investment Manager, the Distributor, the Transfer Agent and the Fund’s custodian. The Fund’s Service Provider Contracts are solely among the parties thereto. Shareholders are not parties to, or intended to be third-party beneficiaries of, any Service Provider Contracts. Further, this prospectus, the SAI and any Service Provider Contracts are not intended to give rise to any agreement, duty, special relationship or other obligation between the Fund and any investor, or give rise to any contractual, tort or other rights in any individual shareholder, group of shareholders or other person, including any right to assert a fiduciary or other duty, enforce the Service Provider Contracts against the parties or to seek any remedy thereunder, either directly or on behalf of the Fund. Nothing in the previous sentence should be read to suggest any waiver of any rights under federal or state securities laws.

The Investment Manager, which also serves as the Fund's administrator (the Administrator), Columbia Management, which serves as the Fund's sub-administrator pursuant to an agreement with the Investment Manager (the Sub-Administrator), the Distributor, and the Transfer Agent are all affiliates of Ameriprise Financial. They and their affiliates currently provide key services, including investment advisory, administration, distribution, shareholder servicing and transfer agency services, to the Fund and various other funds, including the Columbia Funds, and are paid for providing these services. These service relationships are described below.

The Investment Manager

Columbia Wanger Asset Management, LLC is located at 71 S. Wacker Drive, Suite 2500, Chicago, Illinois 60606. As of March 31, 2022, the Investment Manager had assets under management of approximately $9.2 billion. The Investment Manager is a registered investment adviser and wholly-owned subsidiary of Columbia Management, which is a wholly-owned subsidiary of Ameriprise Financial. In addition to serving as an investment adviser to mutual funds, the Investment Manager acts as an investment manager for other private funds and institutional accounts.

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Subject to oversight by the Board, the Investment Manager manages the day-to-day operations of the Fund, determining what securities and other investments the Fund should buy or sell and executing portfolio transactions. The Investment Manager may use the research and other capabilities of its affiliates and third parties in managing the Fund’s investments.

The Fund pays the Investment Manager a fee for its investment advisory services. The fee is calculated as a percentage of the daily net assets of the Fund and is paid monthly. In February 2022, the Board approved a reduction in the advisory fee rates payable to the Investment Manager by the Fund. The new advisory fee, which is effective May 1, 2022, is equal to 0.740% on the first $700 million of the Fund's average daily net assets, gradually declining to 0.630% as assets increase. For the Fund’s most recent fiscal year, aggregate fees paid to the Investment Manager by the Fund amounted to 0.92% of average daily net assets of the Fund, before any applicable reimbursements.

A discussion regarding the basis for the Board’s approval of the renewal of the Fund’s investment management services agreement with the Investment Manager is available in the Fund’s annual report to shareholders for the fiscal year ended December 31, 2021.

The Investment Manager and its investment advisory affiliates, including Columbia Management (Affiliates), around the world may coordinate in providing services to their clients. From time to time, the Investment Manager may engage its Affiliates to provide a variety of services such as investment research, investment monitoring, trading, and discretionary investment management (including portfolio management and proxy voting) to certain accounts managed by the Investment Manager, including the Fund. These Affiliates will provide services to the Fund and other accounts of the Investment Manager either pursuant to delegation agreements, personnel-sharing agreements or similar inter-company or other arrangements or relationships and the Fund will pay no additional fees and expenses as a result of any such arrangements or relationships. These Affiliates, like the Investment Manager, are direct or indirect subsidiaries of Ameriprise Financial and are registered with the appropriate respective regulators and, where required, the SEC and the Commodity Futures Trading Commission in the United States.

Pursuant to some of these arrangements or relationships, certain personnel of Columbia Management and other Affiliates may serve as “associated persons” or officers of the Investment Manager and, in this capacity, subject to the oversight and supervision of the Investment Manager and consistent with the investment objectives, policies and limitations set forth in this prospectus and the Fund's SAI, and with the Investment Manager’s and the Funds’ compliance policies and procedures, may provide such services to the Fund.

Portfolio Managers

Information about the portfolio managers primarily responsible for overseeing the Fund’s investments is shown below. The SAI provides additional information about the portfolio managers, including information relating to compensation, other accounts managed by the portfolio managers, and ownership by the portfolio managers of Fund shares.

Portfolio Management	Title	Role with Fund	Service with the Fund Since
Daniel Cole, CFA	Senior Portfolio Manager of Columbia Management and Vice President of the Investment Manager	Co-Portfolio Manager since May 2022	2021
Erika K. Maschmeyer, CFA	Director of Research (U.S.), Portfolio Manager and Analyst at the Investment Manager	Co-Portfolio Manager since 2021	2016
John L. Emerson, CFA	Portfolio Manager and Analyst at the Investment Manager	Co-Portfolio Manager since 2021	2003

Mr. Cole joined Columbia Management, an affiliate of the Investment Manager, in 2014 and has served as a Vice President of the Investment Manager since April 2021 and as a Vice President of the Trust since March 2022. Mr. Cole began his investment career in 1993 and earned a B.S. from Guilford College and an M.B.A. in finance from Virginia Polytechnic Institute and State University.

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Ms. Maschmeyer has been associated with the Investment Manager as an investment professional since 2016. Ms. Maschmeyer heads the Investment Manager's U.S. equity research efforts and has been a Vice President of the Trust since March 2020. Prior to joining the Investment Manager, Ms. Maschmeyer was a research analyst at an investment advisory firm where she was responsible for U.S. consumer discretionary/staples investments. Ms. Maschmeyer began her investment career in 2001 and earned a B.A. from Denison University and an M.B.A from the University of Chicago.

Mr. Emerson has been associated with the Investment Manager or its predecessors as an investment professional since 2003 and has been a Vice President of the Trust since March 2020. Prior to joining the Investment Manager, Mr. Emerson was an analyst at an equity research firm. Mr. Emerson began his investment career in 2002 and earned a B.S. from the University of Missouri and an M.B.A from the University of Chicago.

The Administrator

Columbia Wanger Asset Management, LLC is responsible for overseeing the administrative operations of the Fund, including the general supervision of the Fund’s operations, coordination of the Fund’s service providers, and the provision of office facilities and related clerical and administrative services. The Administrator retains the Sub-Administrator to perform many of these services (including fund accounting), and pays a fee for the services of the Sub-Administrator. The Fund pays the Administrator a fee for its services, plus certain out-of-pocket expenses. The fee is calculated as an annual percentage of the Trust’s aggregate average daily net assets and is paid monthly, as follows:

Annual Administration Fee, as a % of Aggregate Daily Net Assets of the Trust:
Up to $8 billion	0.050%
$8 billion to $16 billion	0.040%
$16 billion to $35 billion	0.030%
$35 billion to $45 billion	0.025%
$45 billion and over	0.015%

The Distributor

Shares of the Fund are distributed by Columbia Management Investment Distributors, Inc., which is located at 290 Congress Street, Boston, MA 02210. The Distributor is a registered broker-dealer and an indirect, wholly-owned subsidiary of Ameriprise Financial. The Distributor and its affiliates may pay commissions, distribution and service fees and/or other compensation to entities, including Ameriprise Financial affiliates, for selling shares and providing services to investors.

The Transfer Agent

Columbia Management Investment Services Corp. is a registered transfer agent and wholly-owned subsidiary of Ameriprise Financial. The Transfer Agent is located at 290 Congress Street, Boston, MA 02210, and its responsibilities include processing purchases, redemptions and exchanges of Fund shares, calculating and paying distributions, maintaining shareholder records, preparing account statements and providing customer service. The Transfer Agent has engaged DST Asset Manager Solutions, Inc. to provide various shareholder or “sub-transfer agency” services. In addition, the Transfer Agent enters into agreements with various financial intermediaries through which you may hold Fund shares, pursuant to which the Transfer Agent pays these financial intermediaries for providing certain shareholder services. Depending on the type of account, the Fund pays the Transfer Agent a per account fee for each open account and compensates the Transfer Agent for certain out-of-pocket expenses, including certain payments to financial intermediaries through which shares are held. In addition, subject to certain limitations, the Fund compensates the Transfer Agent for payments made to financial intermediaries for the shareholder services that the intermediaries provide, in amounts that vary by share class and with the type of intermediary and the type of shareholder services provided. The Transfer Agent is contractually obligated to oversee such intermediaries for the purpose of reasonably assuring their compliance with applicable law and the terms of their agreements to provide the shareholder services. For more information about Shareholder Services fees, see Choosing a Share Class — Financial Intermediary Compensation.

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Other Roles and Relationships of Ameriprise Financial and its Affiliates — Certain Conflicts of Interest

This section describes certain actual and potential conflicts of interest that arise from the financial services activities of Ameriprise Financial and its affiliates. Ameriprise Financial is a major financial services company, engaged in a broad range of financial activities beyond the fund-related activities of the Investment Manager, including: insurance, broker-dealer (sales and trading), asset management and financial services. As a consequence of these activities, Ameriprise Financial or its affiliates may have interests arising from their other business lines that conflict with the interests of the Fund. These activities may also, from time to time, place certain investment constraints on the management of the Fund that might not otherwise arise.

As described in More Information About the Fund - Primary Service Provider Contracts, the Investment Manager, Administrator, Sub-Administrator, Distributor and Transfer Agent are all affiliates of Ameriprise Financial. In addition to the services that they provide to the Fund, they also provide substantially similar services (for which they are compensated) to other clients and customers, including the Columbia Funds. Ameriprise Financial and its other affiliates may also provide services (for which they are compensated) to the Fund, other Columbia Funds or other clients and customers.

Examples of activities that could lead to conflicts of interest and/or impose limitations that could affect the Fund include the following:

■ the Investment Manager and other Ameriprise Financial affiliates may receive compensation and other benefits related to the management/administration of the Fund and the other Columbia Funds and the sale of their shares;

■ there may be competition for limited investment opportunities that must be allocated among the Fund, the other Columbia Funds and other clients and customers of the Investment Manager (which can include affiliates of the Investment Manager) that may have the same or similar investment objectives as the Fund;

■ management of the Fund may diverge from other Columbia Funds or other clients and customers of the Investment Manager or Ameriprise Financial affiliates, for example, advice given to the Fund may differ from, or conflict with, advice given to other funds or accounts;

■ there may be regulatory or investment restrictions imposed on the investment activities of the Investment Manager arising from the activities or holdings of other Columbia Funds or other clients or customers of the Investment Manager or Ameriprise Financial and its affiliates, for example, caps on the aggregate amount of certain types of investments or in holdings of particular portfolio companies that may be made by affiliated entities, including the Fund;

■ Ameriprise Financial or its affiliates may have potentially conflicting relationships with companies and other entities in which the Fund invests; and

■ there may be regulatory and other restrictions relating to the sharing of information between Ameriprise Financial and its affiliates, including the Investment Manager, for example, if an affiliated entity were in possession of non-public information, the Investment Manager might be prohibited by law from using that information in connection with the management of the Fund.

The Investment Manager and Ameriprise Financial have adopted various policies and procedures that are intended to identify, monitor and address conflicts of interest. However, there is no absolute assurance that these policies, procedures and disclosures will be effective.

Additional information about Ameriprise Financial and the types of conflicts of interest and other matters referenced above is set forth in the Investment Advisory and Other Services – Other Roles and Relationships of Ameriprise Financial and Affiliates – Certain Conflicts of Interest section of the SAI. Investors in the Fund should carefully review these disclosures and consult with their financial advisor if they have any questions.

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Certain Legal Matters

Ameriprise Financial and certain of its affiliates are involved in the normal course of business in legal proceedings which include regulatory inquiries, arbitration and litigation, including class actions concerning matters arising in connection with the conduct of its activities as a diversified financial services firm. Ameriprise Financial believes that the Fund is not currently the subject of, and that neither Ameriprise Financial nor any of its affiliates are the subject of, any pending legal, arbitration or regulatory proceedings that are likely to have a material adverse effect on the Fund or the ability of Ameriprise Financial or its affiliates to perform under their contracts with the Fund. Information regarding certain pending and settled legal proceedings may be found in the Fund’s shareholder reports and in the SAI. Additionally, Ameriprise Financial is required to make quarterly (10-Q), annual (10-K) and, as necessary, 8-K filings with the SEC on legal and regulatory matters that relate to Ameriprise Financial and its affiliates. Copies of these filings may be obtained by accessing the SEC website at sec.gov.

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Choosing a Share Class

The Funds

The Columbia Acorn Funds and the other Columbia Funds generally share the same policies and procedures for investor services, as described below. Together, the Fund and the other Columbia Acorn Funds, along with the Columbia Funds, are referred to herein as the Funds.

Funds Contact Information

Additional information about the Funds, including sales charges and other class features and policies, can be obtained, free of charge, at columbiathreadneedleus.com,* by calling toll-free 800.345.6611, or by writing (regular mail) to Columbia Management Investment Services Corp., P.O. Box 219104, Kansas City, MO 64121-9104 or (express mail) Columbia Management Investment Services Corp., c/o DST Asset Manager Solutions, Inc., 430 W 7^th Street, Ste 219104, Kansas City, MO 64105-1407.

* The website references in this prospectus are inactive links and information contained in or otherwise accessible through the referenced websites does not form a part of this prospectus.

 FUNDamentals

Financial Intermediaries

The term “financial intermediary” refers to the selling and servicing agents that are authorized to sell and/or service shares of the Funds. Financial intermediaries include broker-dealers and financial advisors as well as firms that employ broker-dealers and financial advisors, including, for example, brokerage firms, banks, investment advisers, third party administrators and other firms in the financial services industry.

Omnibus Accounts

The term “omnibus account” refers to a financial intermediary’s account with the Fund (held directly through the Transfer Agent) that represents the combined holdings of, and transactions in, Fund shares of one or more clients of the financial intermediary (beneficial Fund shareholders). Omnibus accounts are held in the name of the financial intermediaries and not in the name of the beneficial Fund shareholders invested in the Fund through omnibus accounts.

Retirement Plans and Omnibus Retirement Plans

The term “retirement plan” refers to retirement plans created under Sections 401(a), 401(k), 457 and 403(b) of the Internal Revenue Code of 1986, as amended (the Code), and non-qualified deferred compensation plans governed by Section 409A of the Code and similar plans, but does not refer to individual retirement plans, such as traditional IRAs and Roth IRAs. The term “omnibus retirement plan” refers to a retirement plan that has a plan-level or omnibus account with the Transfer Agent.

Networked Accounts

Networking, offered by the Depository Trust & Clearing Corporation’s Wealth Management Services (WMS), is the industry standard IT system for mutual fund account reconciliation and dividend processing.

Summary of Share Class Features

Each share class has its own investment eligibility criteria, cost structure and other features. You may not be eligible to invest in every share class. Your financial intermediary may not make every share class available or may cease to make available one or more share classes of the Fund. The share class you select through your financial intermediary may have higher fees and/or sales charges than other classes of shares available through other financial intermediaries. An investor transacting in a class of Fund shares without any front-end sales charge, contingent deferred sales charge (CDSC), or other asset-based fee for sales or distribution, such as a Rule 12b-1 fee, may be required to pay a commission to the financial intermediary for effecting such transactions. Each investor’s personal situation is different and you may wish to discuss with your financial intermediary the share classes the Fund offers, which share classes are available to you and which share class(es) is/are appropriate for you. In all instances, it is your responsibility to notify your financial intermediary or (for Direct-at-Fund Accounts, as

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defined below) the Fund at the time of purchase of any relationship or other facts that may qualify you for sales charge waivers or discounts. The Fund, the Distributor and the Transfer Agent do not provide investment advice or make recommendations regarding Fund share classes. Your financial intermediary may provide advice and recommendations to you, such as which share class(es) is/are appropriate for you.

When deciding which class of shares to buy, you should consider, among other things:

■ The amount you plan to invest.

■ How long you intend to remain invested in the Fund.

■ The fees (e.g., sales charge or “load”) and expenses for each share class.

■ Whether you may be eligible for a reduction or waiver of sales charges when you buy or sell shares.

 FUNDamentals

Front-End Sales Charge Calculation

The front-end sales charge is calculated as a percentage of the offering price.

■ The net asset value (NAV) per share is the price of a share calculated by the Fund every business day.

■ The offering price per share is the NAV per share plus any front-end sales charge (or load) that applies.

The dollar amount of any applicable front-end sales charge is the difference between the offering price of the shares you buy and the NAV of those shares. To determine the front-end sales charge you will pay when you buy Class A shares, the Fund will add the amount of your investment to the value of your account (and any other accounts eligible for aggregation of which you or your financial intermediary notifies the Fund) and base the sales charge on the aggregate amount. For information on account value aggregation, sales charge waivers and other important information, see Choosing a Share Class — Reductions/Waivers of Sales Charges.

 FUNDamentals

Contingent Deferred Sales Charge

A contingent deferred sales charge (CDSC) is a sales charge applied at the time you sell your shares, unlike a front-end sales charge that is applied at the time of purchase. A CDSC can vary based on the length of time that you have held your shares. A CDSC is applied to the NAV at the time of your purchase or sale, whichever is lower, and will not be applied to any shares you receive through Fund distribution reinvestments or any amount that represents appreciation in the value of your shares. For purposes of calculating a CDSC, the start of the holding period is generally the first day of the month in which your purchase was made.

When you place an order to sell shares of a class that has a CDSC, the Fund will first redeem any shares that are not subject to a CDSC, followed by those you have held the longest. This means that if a CDSC is imposed, you cannot designate the individual shares being redeemed for U.S. federal income tax purposes. You should consult your tax advisor about the tax consequences of investing in the Fund. In certain circumstances, the CDSC may not apply. See Choosing a Share Class — Reductions/Waivers of Sales Charges for details.

Share Class Features

The following summarizes the primary features of Class A, Class Adv, Class C, Class Inst, Class Inst2, Class Inst3, and Class R shares.

Not all Funds offer every class of shares. The Fund offers the class(es) of shares set forth on the cover of this prospectus and may offer other share classes through a separate prospectus. Although certain share classes are generally closed to new and/or existing investors, information relating to these share classes is included in the table below because certain qualifying purchase orders are permitted, as described below.

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The sales charge reductions and waivers available to investors who purchase and hold their Fund shares through different financial intermediaries may vary. Appendix A describes financial intermediary-specific reductions and/or waiver policies. A shareholder transacting in Fund shares through a financial intermediary identified in Appendix A should carefully read the terms and conditions of Appendix A. A reduction and/or waiver that is specific to a particular financial intermediary is not available to Direct-at-Fund Accounts, as defined below, or through another financial intermediary. The information in Appendix A may be provided by, or compiled from or based on information provided by the financial intermediaries identified in Appendix A. To obtain additional information regarding any sales charge reduction and/or waiver described in Appendix A, and to ensure that you receive any such reductions or waivers that may be available to you, please consult your financial intermediary.

Share Class	Eligible Investors; Minimum Initial Investments; Conversion Features(a)	Front-End Sales Charges(b)	Contingent Deferred Sales Charges (CDSCs)(b)	Sales Charge Reductions/Waivers	Maximum Distribution and/or Service (12b-1) Fees(c)
Class A	Eligibility: Available to the general public for investment Minimum Initial Investment: $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts (as described below))	5.75% maximum, declining to 0.00% on investments of $1 million or more	CDSC on certain investments of between $1 million and $50 million redeemed within 18 months after purchase charged as follows: • 1.00% CDSC if redeemed within 12 months after purchase and • 0.50% CDSC if redeemed more than 12, but less than 18, months after purchase	Reductions: yes, see Choosing a Share Class — Reductions/Waivers of Sales Charges – Class A Shares Front-End Sales Charge Reductions Waivers: yes, on Fund distribution reinvestments. For additional waivers, see Choosing a Share Class — Reductions/Waivers of Sales Charges – Class A Shares Front-End Sales Charge Waivers, as well as Choosing a Share Class — CDSC Waivers – Class A and Class C Financial intermediary-specific waivers are also available, see Appendix A	Service Fee: 0.25%
Class Adv	Eligibility: Available only to (i) omnibus retirement plans, including self-directed brokerage accounts within omnibus retirement plans that clear through institutional no transaction fee (NTF) platforms; retirement plans; (ii) trust companies or similar institutions; (iii) broker-dealers, banks, trust companies and similar institutions that clear Fund share transactions for their client or customer investment advisory or similar accounts through designated financial intermediaries and their mutual fund trading platforms that have been granted specific written authorization from the Transfer Agent with respect to Class Adv eligibility apart from selling, servicing or similar agreements; (iv) 501(c)(3) charitable organizations; (v) 529 plans; (vi) health savings accounts; (vii) investors participating in a fee-based advisory program sponsored by a financial intermediary or other entity that is not compensated by the Fund for those services, other than payments for shareholder servicing or sub-accounting performed in place	None	None	N/A	None

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Share Class	Eligible Investors; Minimum Initial Investments; Conversion Features(a)	Front-End Sales Charges(b)	Contingent Deferred Sales Charges (CDSCs)(b)	Sales Charge Reductions/Waivers	Maximum Distribution and/or Service (12b-1) Fees(c)
	of the Transfer Agent; and (viii) commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Adv shares within such platform. Minimum Initial Investment: None, except in the case of (viii) above, which is $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts)
Class C	Eligibility: Available to the general public for investment Minimum Initial Investment: $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts) Conversion Feature: Yes. Effective April 1, 2021, Class C shares generally automatically convert to Class A shares of the same Fund in the month of or the month following the 8-year anniversary of the Class C shares purchase date. Prior to April 1, 2021, Class C shares generally automatically converted to Class A shares of the same Fund in the month of or the month following the 10-year anniversary of the Class C shares purchase date.(a)	None	1.00% on certain investments redeemed within one year of purchase	Waivers: yes, on Fund distribution reinvestments. For additional waivers, see Choosing a Share Class — CDSC Waivers – Class A and Class C Financial intermediary-specific CDSC waivers are also available, see Appendix A	Distribution Fee: 0.75% Service Fee: 0.25%
Class Inst	Eligibility: Available only to certain eligible investors, which are subject to different minimum investment requirements, ranging from $0 to $2,000, including investors who purchase Fund shares through commissionable brokerage platforms where the financial intermediary holds the shares in an omnibus account and, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst shares within such platform; closed to (i) accounts of financial intermediaries that clear Fund share transactions for their client or customer accounts through designated financial intermediaries and their mutual fund	None	None	N/A	None

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Share Class	Eligible Investors; Minimum Initial Investments; Conversion Features(a)	Front-End Sales Charges(b)	Contingent Deferred Sales Charges (CDSCs)(b)	Sales Charge Reductions/Waivers	Maximum Distribution and/or Service (12b-1) Fees(c)
	trading platforms that have been given specific written notice from the Transfer Agent of the termination of their eligibility for new purchases of Class Inst shares and (ii) omnibus group retirement plans, subject to certain exceptions(d) Minimum Initial Investment: See Eligibility above
Class Inst2	Eligibility: Available only to (i) certain registered investment advisers and family offices that clear Fund share transactions for their client or customer accounts through designated financial intermediaries and their mutual fund trading platforms that have been granted specific written authorization from the Transfer Agent with respect to Class Inst2 eligibility apart from selling, servicing or similar agreements; (ii) omnibus retirement plans(d); (iii) health savings accounts, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst2 shares within such platform and that Fund shares are held in an omnibus account; and (iv) institutional investors that are clients of the Columbia Threadneedle Global Institutional Distribution Team that invest in Class Inst2 shares for their own account through platforms approved by the Distributor or an affiliate thereof to offer and/or service Class Inst2 shares within such platform. Minimum Initial Investment: None	None	None	N/A	None
Class Inst3	Eligibility: Available to: (i) group retirement plans that maintain plan-level or omnibus accounts with the Fund(d); (ii) institutional investors that are clients of the Columbia Threadneedle Global Institutional Distribution Team that invest in Class Inst3 shares for their own account through platforms approved by the Distributor or an affiliate thereof to offer and/or service Class Inst3 shares within such platform; (iii) collective trust funds; (iv) affiliated or unaffiliated mutual funds (e.g., funds operating as funds-of-funds); (v) fee-based platforms of financial intermediaries (or the clearing intermediary they trade through) that have an agreement with the	None	None	N/A	None

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Share Class	Eligible Investors; Minimum Initial Investments; Conversion Features(a)	Front-End Sales Charges(b)	Contingent Deferred Sales Charges (CDSCs)(b)	Sales Charge Reductions/Waivers	Maximum Distribution and/or Service (12b-1) Fees(c)
	Distributor or an affiliate thereof that specifically authorizes the financial intermediary to offer and/or service Class Inst3 shares within such platform, provided also that Fund shares are held in an omnibus account; (vi) commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst3 shares within such platform and that Fund shares are held in an omnibus account; (vii) health savings accounts, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst3 shares within such platform and that Fund shares are held in an omnibus account; and (viii) bank trust departments, subject to an agreement with the Distributor that specifically authorizes offering Class Inst3 shares and provided that Fund shares are held in an omnibus account. In each case above where noted that Fund shares are required to be held in an omnibus account, the Distributor, may, in its discretion, determine to waive this requirement. Minimum Initial Investment: No minimum for the eligible investors described in (i), (iii), (iv) and (v) above; $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts) for the eligible investors described in (vi) above; and $1 million for all other eligible investors, unless waived in the discretion of the Distributor
Class R	Eligibility: Available only to eligible retirement plans, health savings accounts and, in the sole discretion of the Distributor, other types of retirement accounts held through platforms maintained by financial intermediaries approved by the Distributor Minimum Initial Investment: None	None	None	N/A	Distribution Fee: 0.50%

(a) For more information on the conversion of Class C shares to Class A shares, see Choosing a Share Class — Sales Charges and Commissions — Class C Shares —Conversion to Class A Shares.

(b) For more information on applicable sales charges, see Choosing a Share Class — Sales Charges and Commissions, and for information about certain exceptions to these sales charges, see Choosing a Share Class — Reductions/Waivers of Sales Charges.

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(c) These are the maximum applicable distribution and/or service fees under the Fund’s Rule 12b-1 plan. Because these fees are paid out of Fund assets on an ongoing basis, over time these fees will increase the cost of your investment and may cost you more than paying other types of distribution and/or service fees. For more information on distribution and service fees, see Choosing a Share Class — Distribution and Service Fees.

(d) These share classes are closed to new accounts generally or to new accounts of certain categories of investors, subject to certain conditions, as summarized below and described in more detail under Buying, Selling and Exchanging Shares — Buying Shares — Eligible Investors:

•  Class Inst Shares: Financial intermediaries that clear Fund share transactions through designated financial intermediaries and their mutual fund trading platforms that were given specific written notice from the Transfer Agent of the termination, effective March 29, 2013, of their eligibility for new purchases of Class Inst shares and omnibus retirement plans are not permitted to establish new Class Inst accounts, subject to certain exceptions. Omnibus retirement plans that opened and, subject to exceptions, funded a Class Inst account as of close of business on March 28, 2013, and have continuously held Class Inst shares in such account after such date, may generally continue to make additional purchases of Class Inst shares, open new Class Inst accounts and add new participants. In certain circumstances and in the sole discretion of the Distributor, omnibus retirement plans affiliated with a grandfathered plan may also open new Class Inst accounts. Accounts of financial intermediaries (other than omnibus retirement plans) that clear Fund share transactions for their client or customer accounts through designated financial intermediaries and their mutual fund trading platforms are not permitted to establish new Class Inst accounts or make additional purchases of Class Inst shares (other than through reinvestment of distributions).

•  Class Inst2 Shares. Shareholders with Class Inst2 accounts funded before November 8, 2012 who do not satisfy the current eligibility criteria for Class Inst2 shares may not establish new Class Inst2 accounts but may continue to make additional purchases of Class Inst2 shares in existing accounts. In addition, investment advisory programs and similar programs that opened a Class Inst2 account as of May 1, 2010, and continuously hold Class Inst2 shares in such account after such date, may generally not only continue to make additional purchases of Class Inst2 shares but also open new Class Inst2 accounts and add new shareholders in the program.

•  Class Inst3 Shares: Shareholders with Class Inst3 accounts funded before November 8, 2012 who do not satisfy the current eligibility criteria for Class Inst3 shares may not establish new accounts for such share class but may continue to make additional purchases of Class Inst3 shares in existing accounts.

Sales Charges and Commissions

Sales charges, commissions, and distribution fees compensate financial intermediaries (typically your financial advisor) for selling shares to you, and service fees compensate financial intermediaries for maintaining and servicing the shares held in your account with them. Distribution and service fees are discussed in a separate sub-section below. Depending on which share class you choose and the financial intermediary through which you purchase your shares, you may pay these charges at potentially different levels at the outset as a front-end sales charge, at the time you sell your shares as a CDSC and/or over time in the form of distribution and/or service fees. You may be required to pay brokerage commissions and other fees to financial intermediaries when transacting in any class of Fund shares, including those that do not assess any front-end sales charge, contingent deferred sales charge, or other asset-based fee for sales or distribution. Such brokerage commissions and other fees are set by the financial intermediary.

As described in more detail below, Class A shares have a front-end sales charge, which is deducted from your purchase price when you buy your shares, and results in a smaller dollar amount being invested in the Fund than the purchase price you pay (unless you qualify for a waiver or reduction of the sales charge). The Fund’s other share classes do not have a front-end sales charge, so the full amount of your purchase price is invested in those classes. Class A shares have lower ongoing distribution and/or service fees than Class C and Class R shares of the Fund. Over time, Class C and Class R shares can incur distribution and/or service fees that are equal to or more than the front-end sales charge and the distribution and/or service fees you would pay for Class A shares. Although the full amount of your purchase price of Class C and Class R shares is invested in a Fund, your return on this money will be reduced by the expected higher annual expenses of Class C and Class R shares. In this regard, note that effective April 1, 2021, Class C shares will generally automatically convert to Class A shares of the same Fund in the month of or the month following the 8-year anniversary of the Class C shares purchase date (prior to April 1, 2021, the 10-year anniversary of such date). The Fund may convert Class C shares held through a financial intermediary to Class A shares sooner in connection with the withdrawal of Class C shares of the Fund from the financial intermediary’s platform or accounts. No sales charge or other charges will apply in connection with such conversions, and the conversions are free from U.S. federal income tax. Once your Class C shares convert to Class A shares, your total returns from an investment in the Fund may increase as a result of the lower operating costs of Class A shares. Class Adv, Class Inst, Class Inst2 and Class Inst3 shares of the Fund do not have distribution and/or service fees.

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Whether the ultimate cost is higher for one share class over another depends on the amount you invest, how long you hold your shares, the fees (i.e., sales charges) and expenses of the class and whether you are eligible for reduced or waived sales charges, if available. You are responsible for choosing the share class most appropriate for you after taking into account your share class eligibility, class-specific features, and any applicable reductions in, or waivers of, sales charges. For more information, see Choosing a Share Class – Reductions/Waivers of Sales Charges. We encourage you to consult with a financial advisor who can help you with your investment decisions. Please contact your financial intermediary for more information about services, fees and expenses, and other important information about investing in the Fund, as well as with any questions you may have about your investing options. In all instances, it is your responsibility to notify your financial intermediary or (for Direct-at-Fund Accounts, as defined below) the Fund at the time of purchase of any relationship or other facts that may qualify you for sales charge waivers or discounts.

Class A Shares — Front-End Sales Charge

Unless your purchase qualifies for a waiver (e.g., you buy the shares through reinvested Fund dividends or distributions or subject to an applicable financial intermediary-specific waiver), you will pay a front-end sales charge when you buy Class A shares, resulting in a smaller dollar amount being invested in a Fund than the purchase price you pay. The Class A shares sales charge is waived on Class C shares converted to Class A shares. For more information about sales charge waivers and reduction opportunities, see Choosing a Share Class — Reductions/Waivers of Sales Charges and Appendix A.

The Distributor receives the sales charge and re-allows (or pays) a portion of the sales charge to the financial intermediary through which you purchased the shares. The Distributor retains the balance of the sales charge.

The front-end sales charge you will pay on Class A shares:

■ depends on the amount you are investing (generally, the larger the investment, the smaller the percentage sales charge), and

■ is based on the total amount of your purchase and the value of your account (and any other accounts eligible for aggregation of which you or your financial intermediary notifies the Fund).

The table below presents the front-end sales charge as a percentage of both the offering price and the net amount invested.

Class A Shares — Front-End Sales Charge — Breakpoint Schedule
Breakpoint Schedule For:	Dollar amount of shares bought(a)	Sales charge as a % of the offering price(b)	Sales charge as a % of the net amount invested(b)	Amount retained by or paid to financial intermediaries as a % of the offering price
Class A Shares	$0–$49,999	5.75%	6.10%	5.00%
	$50,000–$99,999	4.50%	4.71%	3.75%
	$100,000–$249,999	3.50%	3.63%	3.00%
	$250,000–$499,999	2.50%	2.56%	2.15%
	$500,000–$999,999	2.00%	2.04%	1.75%
	$1,000,000 or more	0.00%	0.00%	0.00%(c)

(a) Purchase amounts and account values may be aggregated among all eligible Fund accounts for the purposes of this table. See Choosing a Share Class — Reductions/Waivers of Sales Charges for a discussion of account value aggregation.

(b) Because the offering price is calculated to two decimal places, the dollar amount of the sales charge as a percentage of the offering price and your net amount invested for any particular purchase of Fund shares may be higher or lower depending on whether downward or upward rounding was required during the calculation process. Purchase price includes the sales charge.

(c) For information regarding cumulative commissions paid to your financial intermediary when you buy $1 million or more of Class A shares of a Fund, see Class A Shares — Commissions below.

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Class A Shares — CDSC

In some cases, you'll pay a CDSC if you sell Class A shares that you purchased without a front-end sales charge.

■ If you purchased Class A shares without an initial sales charge because your accounts aggregated between $1 million and $50 million at the time of purchase, you will incur a CDSC if you redeem those shares within 18 months after purchase, which is charged as follows: 1.00% CDSC if shares are redeemed within 12 months after purchase; and 0.50% CDSC if shares are redeemed more than 12, but less than 18, months after purchase.

■ Subsequent Class A share purchases that bring your aggregate account value to $1 million or more (but less than $50 million) will also be subject to a CDSC if you redeem them within the time periods noted above.

Class A Shares — Commissions

The Distributor may pay your financial intermediary an up-front commission when you buy Class A shares. The Distributor generally funds the commission through the applicable sales charge you paid. For more information, see Class A Shares — Front-End Sales Charge above.

The Distributor may also pay your financial intermediary a cumulative commission when you buy Class A shares in amounts not subject to a front-end sales charge, according to the following schedules (assets initially purchased into Class A shares of Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund and Columbia U.S. Treasury Index Fund that were purchased without the application of a front-end sales charge are excluded for purposes of calculating a financial intermediary’s commission under these schedules):

Class A Shares — Commission Schedule (Paid by the Distributor to Financial Intermediaries)
Purchase Amount	Commission Level* (as a % of net asset value per share)
$1 million – $2,999,999	1.00%
$3 million – $49,999,999	0.50%
$50 million or more	0.25%

* The commission level applies to the applicable asset level; therefore, for example, for a purchase of $5 million, the Distributor would pay a commission of 1.00% on the first $2,999,999 and 0.50% on the balance.

Class C Shares — Front-End Sales Charge

You do not pay a front-end sales charge when you buy Class C shares, but you may pay a CDSC when you sell Class C shares. Although Class C shares do not have a front-end sales charge, over time Class C shares can incur distribution and/or service fees that are equal to or more than the front-end sales charge and distribution and/or service fees you would pay for Class A shares. Thus, although the full amount of your purchase of Class C shares is invested in a Fund, any positive investment return on this money may be partially or fully offset by the expected higher annual expenses of Class C shares.

Class C Shares — Conversion to Class A Shares

Effective April 1, 2021, Class C shares of a Fund generally automatically convert to Class A shares of the same Fund in the month of or the month following the 8-year anniversary of the Class C shares purchase date. Prior to April 1, 2021, Class C shares of a Fund generally automatically converted to Class A shares of the same Fund in the month of or in the month following the 10-year anniversary of the Class C shares purchase date. Class C shares held through a financial intermediary in an omnibus account will be converted (pursuant to the financial intermediary’s Class C conversion policy, including those disclosed in Appendix A, which may differ from the Fund’s policy described here) provided that the intermediary is able to track individual shareholders’ holding periods. It is the financial intermediary's (and not the Fund's) responsibility to keep records and to ensure that the shareholder holding period is calculated properly. Not all financial intermediaries are able to track individual shareholders' holding periods. For example, group retirement plans held through third-party intermediaries that hold Class C shares in an omnibus account may not track participant level share lot aging. Please consult with your financial intermediary about your

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eligibility for Class C share conversion. The Fund may convert Class C shares held through a financial intermediary to Class A shares sooner in connection with the withdrawal of Class C shares of the Fund from the financial intermediary's platform or accounts. Once your Class C shares convert to Class A shares, your total returns from an investment in the Fund may increase as a result of the lower operating costs of Class A shares.

The following rules apply to the automatic conversion of Class C shares to Class A shares:

■ Class C share accounts that are Direct-at-Fund Accounts and Networked Accounts for which the Transfer Agent (and not your financial intermediary) sends you Fund account transaction confirmations and statements, convert on or about the 15th day of the month (if the 15th is not a business day, then the next business day thereafter) that they become eligible for automatic conversion provided that the Fund has records that Class C shares have been held for the requisite time period.

■ For purposes of determining the month when your Class C shares are eligible for conversion, the start of the holding period is the first day of the month in which your purchase was made. Your financial intermediary may choose a different day of the month to convert Class C shares. Please contact your financial intermediary for more information on calculating the holding period.

■ Any shares you received from reinvested distributions on these shares generally will convert to Class A shares at the same time.

■ You’ll receive the same dollar value of Class A shares as the Class C shares that were automatically converted. Class C shares that you received from an exchange of Class C shares of another Fund will convert based on the day you bought the original shares.

■ In addition to the above automatic conversion of Class C to Class A shares policy, the Transfer Agent seeks to convert Class C shares as soon as administratively feasible, regardless of how long such shares have been owned, to Class A shares of the same Fund for Direct-at-Fund Accounts (as defined below) that do not or no longer have a financial intermediary assigned to them. Direct-at-Fund Accounts that do not have a financial intermediary assigned to them are not permitted to purchase Class C shares; Class C share purchase orders received by Direct-at-Fund Accounts that do not have a financial intermediary assigned to the account will automatically be invested in Class A shares of the same Fund.

■ No sales charge or other charges apply in connection with these automatic conversions, and the conversions are free from U.S. federal income tax.

Class C Shares — CDSC

You will pay a CDSC of 1.00% if you redeem Class C shares within 12 months of buying them unless you qualify for a waiver of the CDSC (e.g., the shares you are selling were purchased with reinvested Fund distributions). Redemptions of Class C shares are not subject to a CDSC if redeemed after 12 months. For more information, see Choosing a Share Class — Reductions/Waivers of Sales Charges.

Class C Shares — Commissions

Although there is no front-end sales charge when you buy Class C shares, the Distributor makes an up-front payment (which includes a sales commission and an advance of service fees) directly to your financial intermediary of up to 1.00% of the NAV per share when you buy Class C shares. A portion of this payment may be passed along to your financial advisor. The Distributor seeks to recover this payment through distribution fees of up to 0.75% and shareholder service fees of up to 0.25% it receives under the Fund's Rule 12b-1 plan during the first 12 months following the sale of Class C shares, and any applicable CDSC when you sell your shares. For more information, see Choosing a Share Class — Distribution and Service Fees.

Reductions/Waivers of Sales Charges

The availability of certain sales charge waivers and discounts will depend on whether you purchase your shares directly from the Fund (i.e., a Direct-at-Fund Account, as defined below) or through a financial intermediary. Financial intermediaries may have different policies and procedures regarding the availability of front-end sales charge and/or CDSC waivers. In all instances, it is your responsibility to notify your financial intermediary or (for Direct-at-Fund

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Accounts, as defined below) the Fund at the time of purchase of any relationship or other facts that may qualify you for sales charge waivers or discounts. In order to obtain waivers and discounts not available through a particular financial intermediary, shareholders will have to purchase Fund shares directly from the Fund (if permitted) or through a different financial intermediary. For a description of financial intermediary-specific sales charge reductions and/or waivers, see Appendix A.

Class A Shares Front-End Sales Charge Reductions

The Fund makes available two means of reducing the front-end sales charge that you may pay when you buy Class A shares of a Fund. These types of sales charge reductions are also referred to as breakpoint discounts.

First, through the right of accumulation (ROA), you may combine the value of eligible accounts (as described in the Eligible Accounts section below) maintained by you and members of your immediate family to reach a breakpoint discount level and apply a lower front-end sales charge to your purchase. To calculate the combined value of your eligible Fund accounts in the particular class of shares, the Fund will use the current public offering price per share. For purposes of obtaining a breakpoint discount through ROA, you may aggregate your and your “immediate family” members' ownership (as described in the FUNDamentals box below) of certain classes of shares held in certain account types, as described in the Eligible Accounts section below.

Second, by making a statement of intent to purchase additional shares (commonly referred to as a letter of intent (LOI)), you may pay a lower sales charge on all purchases of Class A shares made within 13 months after the date of your LOI. Your LOI must state the aggregate amount of purchases you intend to make in that 13-month period, which must be at least enough to reach the first (or next) breakpoint of the Fund. The required form of LOI may vary by financial intermediary, so please contact them directly for more information. Five percent of the purchase commitment amount will be placed in escrow. At the end of the 13-month period, the shares will be released from escrow, provided that you have invested the commitment amount. If you do not invest the commitment amount by the end of the 13 months, the remaining amount of the unpaid sales charge will be redeemed from the escrowed shares and the remaining balance released from escrow. To calculate the total value of the purchases you've made under an LOI, the Fund will use the historic cost (i.e., dollars invested and not current market value) of the shares held in each eligible account; reinvested dividends or capital gains, or purchases made through the reinstatement privilege do not count as purchases made under an LOI. For purposes of making an LOI to purchase additional shares, you may aggregate eligible shares owned by you or your immediate family members in eligible accounts, valued as of the day immediately before the initiation of your LOI.

You must request the reduced sales charge (whether through ROA or an LOI) when you buy shares. If you do not complete and file an LOI, or do not request the reduced sales charge at the time of purchase, you will not be eligible for the reduced sales charge. To obtain a breakpoint discount, you must notify your financial intermediary in writing at the time you buy your shares of each eligible account maintained by you and members of your immediate family, including accounts maintained through different financial intermediaries. You and your financial intermediary are responsible for ensuring that you receive discounts for which you are eligible. Please contact your financial intermediary with questions regarding application of the eligible discount to your account. You may be asked by your financial intermediary (or by the Fund if you hold your account directly with the Fund) for account statements or other records to verify your discount eligibility for new and subsequent purchases, including, when applicable, records for accounts opened with a different financial intermediary and records of accounts established by members of your immediate family.

The sales charge reductions available to investors who purchase and hold their Fund shares through different financial intermediaries may vary. For a description of such financial intermediary-specific sales charge reductions, see Appendix A.

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 FUNDamentals

Your “Immediate Family” and Account Value Aggregation

For purposes of obtaining a breakpoint discount for Class A shares, the value of your account will be deemed to include the value of all applicable shares in eligible Fund accounts that are held by you and your “immediate family,” which includes your spouse, domestic partner, parent, step-parent, legal guardian, child under 21, step-child under 21, father-in-law and mother-in-law, provided that you and your immediate family members share the same mailing address. Any Fund accounts linked together for account value aggregation purposes as of the close of business on September 3, 2010 will be permitted to remain linked together. Group retirement plan accounts are valued at the retirement plan level.

Eligible Accounts

The following accounts are eligible for account value aggregation as described above, provided that they are invested in Class A (excluding, in the case of Direct-at-Fund Accounts, Funds that do not assess a front-end sales charge, including Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund and Columbia U.S. Treasury Index Fund, unless such shares were purchased via an exchange from Class A shares of a Fund on which you paid the Class A share applicable front-end sales charge), Class C, Class E, Class Inst or Class V shares of a Fund, or non-retirement plan accounts invested in Class Adv, Class Inst2 or Class Inst3 shares of a Fund: individual or joint accounts; Roth and traditional Individual Retirement Accounts (IRAs); Simplified Employee Pension accounts (SEPs), Savings Investment Match Plans for Employees of Small Employers accounts (SIMPLEs) and Tax Sheltered Custodial Accounts (TSCAs); Uniform Gifts to Minors Act (UGMA)/Uniform Transfers to Minors Act (UTMA) accounts for which you, your spouse, or your domestic partner is parent or guardian of the minor child; revocable trust accounts for which you or an immediate family member, individually, is the beneficial owner/grantor; accounts held in the name of your, your spouse’s, or your domestic partner’s sole proprietorship or single owner limited liability company or S corporation; qualified retirement plan assets, provided that you are the sole owner of the business sponsoring the plan, are the sole participant (other than a spouse) in the plan, and have no intention of adding participants to the plan; and investments in wrap accounts.

The following accounts are not eligible for account value aggregation as described above: accounts of pension and retirement plans with multiple participants, such as 401(k) plans (which are combined to reduce the sales charge for the entire pension or retirement plan and therefore are not used to reduce the sales charge for your individual accounts); investments in 529 plans, donor advised funds, variable annuities, variable insurance products or managed separate accounts; charitable and irrevocable trust accounts; accounts holding shares of money market funds that used the Columbia brand before May 1, 2010; accounts invested in Class R shares of a Fund; and retirement plan accounts invested in Class Adv, Class Inst2 or Class Inst3 shares of a Fund.

Additionally, direct purchases of shares of Columbia Government Money Market Fund may not be aggregated for account value aggregation purposes; however, shares of Columbia Government Money Market Fund acquired by exchange from other Columbia Funds that assess a sales charge may be included in account value aggregation.

Class A Shares Front-End Sales Charge Waivers

There are no front-end sales charges on reinvested Fund distributions. The Class A shares sales charge is waived on conversions of Class C shares to Class A shares. The Distributor may waive front-end sales charges on purchases of Class A shares of the Funds by certain categories of investors, including Board members, certain employees of financial intermediaries, Fund portfolio managers, certain partners and employees of outside legal counsel to the Funds or the Board, separate accounts of an insurance company exempt from registration as an investment company under Section 3(c)(11) of the 1940 Act, registered broker-dealer firms that have an agreement with the Distributor purchasing Fund shares for their investment account only, and qualified employee benefit plan rollovers to Class A

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Columbia Acorn USA®

Choosing a Share Class (continued)

shares in the same Fund (see Appendix S to the SAI for details). For a more complete description of categories of investors who may purchase Class A shares of the Funds at NAV, without payment of any front-end sales charge that would otherwise apply, see Appendix S to the SAI.

In addition, certain types of purchases of Class A shares may be made at NAV. The Distributor may waive front-end sales charges on (i) purchases (including exchanges) of Class A shares in accounts of financial intermediaries that have entered into agreements with the Distributor to offer Fund shares to self-directed investment brokerage accounts that may or may not charge a transaction fee to customers; (ii) exchanges of Class Inst shares of a Fund for Class A shares of the Fund; (iii) purchases of Class A shares on brokerage mutual fund-only platforms of financial intermediaries that have an agreement with the Distributor that specifically authorizes the offering of Class A shares within such platform; (iv) purchases through certain wrap fee or other products or programs that involve fee-based compensation arrangements that have, or clear trades through a financial intermediary that has, a selling agreement with the Distributor; (v) purchases through state sponsored 529 Plans; (vi) purchases through banks, trust companies, and thrift institutions acting as fiduciaries; (vii) purchases through certain employee benefit plans and certain qualified deferred compensation plans; and (viii) purchases of Class A shares in Direct-at-Fund Accounts (as defined below) that do not have a financial intermediary assigned to them. For a more complete description of these eligible transactions, see Appendix S to the SAI.

The sales charge waivers available to investors who purchase and hold their Fund shares through different financial intermediaries may vary. For a description of such financial intermediary-specific sales charge waivers, see Appendix A.

CDSC Waivers – Class A and Class C

You may be able to avoid an otherwise applicable CDSC when you sell Class A or Class C shares of the Fund. This could happen because of the way in which you originally invested in the Fund, because of your relationship with the Funds or for other reasons. For example, the CDSC will be waived on redemptions of shares: in the event of the shareholder's death; for which no sales commission or transaction fee was paid to an authorized financial intermediary at the time of purchase; purchased through reinvestment of dividends and capital gain distributions; that result from required minimum distributions taken from retirement accounts due to the shareholder reaching the qualified age based on applicable IRS regulations; that result from returns of excess contributions made to retirement plans or individual retirement accounts (subject to certain conditions); initially purchased by an employee benefit plan (for Class A shares) and that are not connected with a plan level termination (for Class C shares); in connection with the Fund's Small Account Policy (which is described in Buying, Selling and Exchanging Shares — Transaction Rules and Policies); held within Direct-at-Fund Accounts that do not have a financial intermediary assigned to them; and by certain other investors and in certain other types of transactions or situations. Restrictions may apply to certain accounts and certain transactions. The Distributor may, in its sole discretion, authorize the waiver of the CDSC for additional classes of investors. The Fund may change or cancel these terms at any time. Any change or cancellation applies only to future purchases. For a more complete description of the available waivers of the CDSC on redemptions of Class A or Class C shares, see Appendix S to the SAI.

The sales charge waivers available to investors who purchase and hold their Fund shares through different financial intermediaries may vary. For a description of such financial intermediary-specific sales charge waivers, see Appendix A.

Repurchases (Reinstatements)

As noted in the table below, you can redeem shares of certain classes (see Redeemed Share Class below) and use such redemption proceeds to buy shares of the Corresponding Repurchase Class without paying an otherwise applicable sales charge and/or CDSC (other than, in the case of Direct-at-Fund Accounts, redemptions from Funds that do not assess a front-end sales charge, including Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund and Columbia U.S. Treasury Index Fund, unless such shares were purchased via an exchange from Class A shares of a Fund on which you paid the Class A share applicable front-end sales charge) within 90 days, up to the amount of the redemption proceeds.

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Choosing a Share Class (continued)

Repurchases (Reinstatements)
Redeemed Share Class	Corresponding Repurchase Class
Class A	Class A
Class C	Class C

Any CDSC paid upon redemption of your Class A or Class C shares of a Fund will not be reimbursed.

To be eligible for the repurchase (or reinstatement) privilege, the purchase must be made into an account for the same owner, but does not need to be into the same Fund from which the shares were sold. The Transfer Agent, Distributor or their agents must receive a written reinstatement request from you or your financial intermediary within 90 days after the shares are redeemed. The purchase of the Corresponding Repurchase Class (as noted in the table above) through this repurchase (or reinstatement) privilege will be made at the NAV of such shares next calculated after the request is received in “good form.” Systematic withdrawals and purchases are excluded from this policy.

Restrictions and Changes in Terms and Conditions

Restrictions may apply to certain accounts and certain transactions. The Funds and/or the Distributor may change or cancel these terms and conditions at any time. Unless you provide your financial intermediary with information in writing about all of the factors that may count toward available reductions or waivers of an applicable sales charge, there can be no assurance that you will receive all of the reductions and waivers for which you may be eligible. To the extent your Fund account is held directly with the Fund, you should provide this information to the Fund when placing your purchase or redemption order. Please see Appendix A to this prospectus and Appendix S of the SAI for more information about sales charge waivers.

Distribution and Service Fees

The Board has approved, and the Columbia Acorn Funds have adopted, a distribution plan pursuant to Rule 12b-1 under the 1940 Act that sets the distribution and/or service fees that are periodically deducted from the Funds’ assets. These fees are calculated daily, may vary by share class and are intended to compensate the Distributor and/or eligible financial intermediaries for, with regard to distribution fees, selling Fund shares and, with regard to service fees, directly or indirectly providing services to shareholders. Because the fees are paid out of the Fund's assets on an ongoing basis, they will increase the cost of your investment over time.

The table below shows the maximum annual distribution and/or service fees (as an annual percentage of average daily net assets) and the combined amount of such fees applicable to each share class of the Columbia Acorn Funds:

	Distribution Fee	Service Fee	Combined Total
Class A	None	0.25%	0.25%
Class Adv	None	None	None
Class C	0.75%	0.25%	1.00%
Class Inst	None	None	None
Class Inst2	None	None	None
Class Inst3	None	None	None
Class R	0.50%	None	0.50%

The distribution and/or service fees for Class A, Class C, and Class R shares, as applicable, are subject to the requirements of Rule 12b-1 under the 1940 Act. The Distributor may retain these fees otherwise payable to financial intermediaries if the amounts due are below an amount determined by the Distributor in its sole discretion.

For Class A shares, the Distributor begins to pay these fees immediately after purchase, except in the following case, in which the Distributor begins to pay these fees 12 months after purchase: a purchase of Class A shares of $1 million or more that pay a Class A up-front commission to your financial intermediary and the financial intermediary has opted to receive such commission. The Distributor’s policy to otherwise begin to pay these fees immediately on

Prospectus 2022 39

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Choosing a Share Class (continued)

Class A shares also applies to purchases of funds that do not pay an up-front sales commission on Class A shares, which includes Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund and Columbia U.S. Treasury Index Fund. For Class C shares, the Distributor begins to pay these fees 12 months after purchase. However, for Class C shares, financial intermediaries may opt to decline the up-front payment described in Choosing a Share Class – Sales Charges and Commissions – Class C Shares – Commissions and instead may receive these fees immediately after purchase. If the intermediary opts to receive the up-front payment, the Distributor retains the distribution and service fee for the first 12 months following the sale of Class C shares in order to recover the up-front payment made to financial intermediaries and to pay for other related expenses. For Class R shares, the Distributor begins to pay these fees immediately after purchase.

If you maintain shares of the Fund directly with the Fund, without working with a financial advisor or other financial intermediary, distribution and service fees may be retained by the Distributor as payment or reimbursement for incurring certain distribution and shareholder service related expenses.

Over time, these distribution and/or service fees will reduce the return on your investment and may cost you more than paying other types of sales charges. The Fund will pay these fees to the Distributor and/or to eligible financial intermediaries for as long as the distribution plan continues in effect, which is expected to be indefinitely. However, the Fund may reduce or discontinue payments at any time. Your financial intermediary may also charge you other additional fees for providing services to your account, which may be different from those described here.

Financial Intermediary Compensation

The Distributor, the Investment Manager and their affiliates make payments, from their own resources, to financial intermediaries, including other Ameriprise Financial affiliates, for marketing/sales support services relating to the Funds (Marketing Support Payments). Such payments are generally based upon one or more of the following factors: average net assets of the Funds attributable to that financial intermediary; gross sales of the Funds attributable to that financial intermediary; reimbursement of ticket charges (fees that a financial intermediary charges its representatives for effecting transactions in Fund shares); or a negotiated lump sum payment. While the financial arrangements may vary for each financial intermediary, Marketing Support Payments to any one financial intermediary are generally between 0.01% and 0.40% on an annual basis for payments based on average net assets of the Fund attributable to the financial intermediary, and between 0.05% and 0.25% on an annual basis for firms receiving a payment based on gross sales of the Funds attributable to the financial intermediary. The Distributor, the Investment Manager and their affiliates make payments with respect to a Fund or the Columbia Funds generally on a basis other than those described above or in larger amounts when dealing with certain financial intermediaries. Not all financial intermediaries receive Marketing Support Payments. The Distributor, the Investment Manager and their affiliates do not make Marketing Support Payments with respect to Class Inst3 shares of the Columbia Acorn Funds.

In addition, the Transfer Agent has certain arrangements in place to compensate financial intermediaries, including other Ameriprise Financial affiliates, that hold Fund shares through networked and omnibus accounts, including omnibus retirement plans, for services that they provide to beneficial Fund shareholders (Shareholder Services). Shareholder Services and related fees vary by financial intermediary and according to distribution channel and may include sub-accounting, sub-transfer agency, participant recordkeeping, shareholder or participant reporting, shareholder or participant transaction processing, maintenance of shareholder records, preparation of account statements and provision of customer service, and are not intended to include services that are primarily intended to result in the sale of Fund shares. Payments for Shareholder Services vary by financial intermediary and according to distribution channel, but generally are not expected, with certain limited exceptions, to exceed 0.40% of the average aggregate value of the Fund’s shares. Payments to financial intermediaries in excess of the amounts paid by the Fund are borne by the Distributor, the Investment Manager and/or their affiliates.

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Choosing a Share Class (continued)

Generally, each Fund in the Columbia Acorn Family of Funds compensates the Transfer Agent for payments made for Shareholder Services, for each share class except Class Inst3. Effective July 1, 2017, the Columbia Acorn Funds compensate the Transfer Agent for payments made for Shareholder Services as follows:

Financial Intermediary Distribution Channel	Fee Rate
Retirement	up to 0.18% of Fund assets held by intermediaries or platforms charging an asset-based fee, or $18 per account held by intermediaries or platforms charging a per account fee
Fund supermarket transaction fee (TF)	up to 0.12% of Fund assets held by intermediaries or platforms charging an asset-based fee, or $16 per account held for intermediaries or platforms charging a per account fee
Fund supermarket no-transaction fee (NTF)	up to 0.18% of Fund assets held by intermediaries or platforms charging an asset-based fee, or $18 per account held by intermediaries or platforms charging a per account fee
Bank	up to 0.10% of Fund assets held by intermediaries or platforms charging an asset-based fee, or $20 per account held by intermediaries or platforms charging a per account fee
Broker-dealer	up to 0.13% of Fund assets held by intermediaries or platforms charging an asset-based fee, or $16 per account held by intermediaries or platforms charging a per account fee

With respect to Class Inst2 and Class Inst3 shares of the Fund, total annual compensation payable to the Transfer Agent may not exceed, respectively, 0.07% and 0.02% of the average daily net assets of the Class. For additional details about the application of the Columbia Acorn Funds’ fee limits, please refer to the SAI.

The Transfer Agent does not pay financial intermediaries for Shareholder Services, and the Fund does not compensate the Transfer Agent for any Shareholder Services provided by financial intermediaries with respect to Class Inst3 shares of the Columbia Acorn Funds. The Fund believes that the fee levels paid to the Transfer Agent are reasonably related to the Shareholder Services provided, but payments may vary and there can be no assurance that the Fund will be able to identify with specificity the costs or particular Shareholder Services for which compensation is paid.

In addition to the payments described above, the Distributor, the Investment Manager and their affiliates typically make other payments or allow promotional incentives to certain broker-dealers to the extent permitted by the Securities and Exchange Commission (the SEC) and Financial Industry Regulatory Authority (FINRA) rules and by other applicable laws and regulations.

Amounts paid by the Distributor, the Investment Manager and their affiliates are paid out of their own resources and do not increase the amount paid by you or the Fund. You can find further details in the SAI about the payments made by the Distributor, the Investment Manager and their affiliates, as well as a list of the financial intermediaries, including Ameriprise Financial affiliates, to which the Distributor and the Investment Manager have agreed to make Marketing Support Payments and pay Shareholder Services fees.

Your financial intermediary may charge you fees and commissions in addition to those described in this prospectus. You should consult with your financial intermediary and review carefully any disclosure your financial intermediary provides regarding its services and compensation. Depending on the financial arrangement in place at any particular time, a financial intermediary and its financial advisors may have a conflict of interest or financial incentive for recommending the Fund or a particular share class over others.

Prospectus 2022 41

Columbia Acorn USA®

Buying, Selling and Exchanging Shares

Share Price Determination

The price you pay or receive when you buy, sell or exchange shares is the Fund's next determined net asset value (or NAV) per share for a given share class. The Fund calculates the NAV per share for each class of shares of the Fund at the end of each business day, with the value of the Fund's shares based on the total value of all of the securities and other assets that it holds as of such specified time.

 FUNDamentals

NAV Calculation

Each of the Fund's share classes calculates its NAV per share as follows:

NAV per share =  (Value of assets of the share class) – (Liabilities of the share class)
Number of outstanding shares of the class

 FUNDamentals

Business Days

A business day is any day that the New York Stock Exchange (NYSE) is open. A business day ends at (i) the scheduled close of the NYSE for such day (usually 4:00 p.m. Eastern Time or such other time as the NYSE may schedule), (ii) the scheduled close of the NYSE (usually 4:00 p.m. Eastern Time) on any business day on which the NYSE has an unscheduled close or intraday trading halt or other disruption, regardless of the time of such unscheduled close, halt or disruption or whether trading resumes, or (iii) such other time as the Board may from time to time determine. On holidays and other days when the NYSE is closed, the Fund’s NAV is not calculated and the Fund does not accept buy or sell orders. However, the value of the Fund’s assets may still be affected on such days to the extent that the Fund holds foreign securities that trade on days that foreign securities markets are open.

Equity securities are valued primarily on the basis of market quotations reported on stock exchanges and other securities markets around the world. Certain equity securities, debt securities and other assets are valued differently. For instance, short-term investments maturing in 60 days or less are valued primarily using the amortized cost method and those maturing in excess of 60 days are valued at the readily available market price. For a Fund organized as a fund-of-funds, its investments in other funds are valued at their NAVs. Market quotations are obtained from outside pricing services approved and monitored pursuant to a policy approved by the Fund’s Board.

If a market price is not readily available or is deemed not to reflect market value, the security will be valued in good faith based on a determination of the security's fair value pursuant to the Portfolio Pricing Policy approved by the Board. The Portfolio Pricing Policy provides that fair value determinations will be made using the methodology set forth in the Policy and deemed most appropriate under the circumstances and considering all available, relevant factors and indications of value. The Portfolio Pricing Policy provides that fair valuation may be used to price securities that trade on a foreign exchange when a significant event has occurred after the foreign exchange closes but before the time at which the Fund's share price is calculated. In addition, a statistical fair valuation process is applied daily to adjust prices of foreign securities traded on foreign exchanges in time zones different from the United States utilizing the services of a designated pricing vendor. Although the use of statistical fair valuation is intended to and may decrease opportunities for time zone arbitrage transactions, there can be no assurance that it will successfully decrease arbitrage opportunities. Please consult the SAI for more information on the factors to be considered in making fair value determinations; the significant events that may necessitate fair valuation of foreign securities; and the Fund's statistical fair valuation methodology.

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Buying, Selling and Exchanging Shares (continued)

When fair valuation is used to price securities, the values for those securities may be higher or lower than values used by another fund to price the security. Also, the use of fair valuation may cause the Fund's performance to diverge to a greater degree from the performance of various benchmarks used to compare the Fund's performance because benchmarks generally do not use fair valuation techniques. Because of the judgment involved in fair valuation decisions, there can be no assurance that the value ascribed to a particular security is accurate.

Transaction Rules and Policies

The Fund, the Distributor or the Transfer Agent may refuse any order to buy or exchange shares. If this happens, the Fund will return any money it received, but no interest will be paid on that money. Your financial intermediary may have rules and policies in place that are in addition to or different than those described below.

Order Processing

Orders to buy, sell or exchange Fund shares are processed on business days. Depending upon the class of shares, orders can be made by mail, by telephone or online. Orders received in “good form” by the Transfer Agent or your financial intermediary before the end of a business day are priced at the NAV per share (plus any applicable sales charge) of the Fund's applicable share class on that day. Orders received after the end of a business day will receive the next business day's NAV per share (plus any applicable sales charge). For Direct-at-Fund Accounts (as defined below), when a written order to buy, sell or exchange shares is sent to the Transfer Agent, the share price used to fill the order is the next price calculated by the Fund after the Transfer Agent receives the transaction request in “good form” at its transaction processing center (i.e., the Fund’s express mail address), not the P.O. Box provided for regular mail delivery. The market value of the Fund's investments may change between the time you submit your order and the time the Fund next calculates its NAV per share. The business day that applies to your order is also called the trade date.

“Good Form”

An order is in “good form” if the Transfer Agent or your financial intermediary has received payment (in the case of purchases) and all of the information and documentation it deems necessary to effect your order. For example, when you sell shares, “good form” means that your request (i) has complete instructions and written requests include the signatures of all account owners, (ii) is for an amount that is less than or equal to the shares in your account for which payment has been received and collected, (iii) has a Medallion Signature Guarantee for amounts greater than $100,000 and certain other transactions, as described below, and (iv) includes any other required documents completed and attached. For the documents required for sales by corporations, agents, fiduciaries, surviving joint owners and other legal entities, call 800.345.6611.

Medallion Signature Guarantees

The Transfer Agent may require a Medallion Signature Guarantee for your signature in order to process certain transactions, including if: (i) the transaction amount is over $100,000; (ii) you want your check made payable to someone other than the registered account owner(s); (iii) the address of record has changed within the last 30 days; (iv) you want the check mailed to an address other than the address of record; (v) you want proceeds to be sent according to existing bank account instructions not coded for outgoing Automated Clearing House (ACH) or wire, or to a bank account not on file; or (vi) you are changing legal ownership of your account.

A Medallion Signature Guarantee helps assure that a signature is genuine and not a forgery. A Medallion Signature Guarantee must be provided by an eligible guarantor institution including, but not limited to, the following: a bank, credit union, savings association, broker or dealer that participates in the Securities Transfer Association Medallion Program (STAMP), the Stock Exchange Medallion Program (SEMP) or the New York Stock Exchange Medallion Signature Program (MSP). For other transactions, the Transfer Agent may require a signature guarantee. Notarization by a notary public is not an acceptable signature guarantee. The Transfer Agent reserves the right to reject a signature guarantee and to request additional documentation for any transaction.

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Columbia Acorn USA®

Buying, Selling and Exchanging Shares (continued)

Customer Identification Program

Federal law requires the Fund to obtain and record specific personal information to verify your identity when you open an account. This information may include your name, address, date of birth (for individuals) and taxpayer or other government issued identification (e.g., social security number (SSN) or other taxpayer identification number (TIN)). If you fail to provide the requested information, the Fund may need to delay the date of your purchase or may be unable to open your account, which may result in a return of your investment monies. In addition, if the Fund is unable to verify your identity after your account is open, the Fund reserves the right to close your account or take other steps as deemed reasonable. The Fund will not be liable for any loss resulting from any purchase delay, application rejection or account closure due to a failure to provide proper identifying information.

Small Account Policy — Class A, Class C, and Class Inst Share Accounts Below the Minimum Account Balance

The Funds generally will automatically sell your shares if the value of your Fund account (treating each account of the Fund you own separately from any other account of the Fund you may own) falls below the applicable minimum account balance. Any otherwise applicable CDSC will not be imposed on such an automatic sale of your shares. Generally, you may avoid such an automatic sale by raising your account balance to at least $250 or consolidating your multiple accounts you may have with the Funds through an exchange (so as to maintain at least $250 in each of your accounts). The minimum account balance varies among share classes and types of accounts, as follows:

Minimum Account Balance
	Minimum Account Balance
For all classes and account types except those listed below	$250 (None for accounts with Systematic Investment Plans)
Individual Retirement Accounts for all classes except those listed below	None
Class Adv, Class Inst2, Class Inst3 and Class R	None

For shares held directly with the Funds’ Transfer Agent, if your shares are sold, the Transfer Agent will remit the sale proceeds to you. The Transfer Agent will send you written notification in advance of any automatic sale, which will provide details on how you may avoid such an automatic sale. Generally, you may avoid such an automatic sale by raising your account balance to at least $250, consolidating your multiple accounts you may have with the Funds through an exchange (so as to maintain at least $250 in each of your accounts), or setting up a Systematic Investment Plan. For more information, contact the Transfer Agent or your financial intermediary. The Transfer Agent's contact information (toll-free number and mailing addresses) as well as the Funds’ website address can be found at the beginning of the section Choosing a Share Class.

For shares purchased and held for your benefit through a financial intermediary, the Funds may instruct the intermediary to automatically sell your Fund shares if the transaction can be operationally administered by the intermediary.

Small Account Policy — Class A, Class C, and Class Inst Share Accounts Minimum Balance Fee

If the value of your Fund account (treating each account of the Fund you own separately from any other account of the Fund you may own) falls below the minimum initial investment requirement applicable to you for any reason, including as a result of market decline, your account generally could be subject to a $20 annual fee. The Transfer Agent will reduce the expenses paid by the Fund by any amounts it collects from the assessment of this fee. For Funds that do not have transfer agency expenses against which to offset the amount collected through assessment of this fee, the fee will be paid directly to the Fund. The Funds reserve the right to lower the account size trigger point for the minimum balance fee in any year or for any class of shares when we believe it is appropriate to do so in light of declines in the market value of Fund shares or for other reasons.

For shares held directly with the Funds’ Transfer Agent, this fee will be assessed through the automatic sale of Fund shares in your account. Any otherwise applicable CDSC will not be imposed on such an automatic sale of your shares. The Transfer Agent will send you written notification in advance of assessing any fee, which will provide

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Columbia Acorn USA®

Buying, Selling and Exchanging Shares (continued)

details on how you can avoid the imposition of such fee. Generally, you may avoid the imposition of such fee by raising your Fund account balance, consolidating your multiple accounts you may have with the Funds, or setting up a Systematic Investment Plan that invests at least monthly. For more information, contact the Transfer Agent or your financial intermediary. The Transfer Agent's contact information (toll-free number and mailing addresses) as well as the Funds’ website address can be found at the beginning of the section Choosing a Share Class.

For shares purchased and held for your benefit through a financial intermediary, this fee could be assessed through the automatic sale of Fund shares in your account if instructed by the Fund and the transaction can be operationally administered by the intermediary.

Exceptions to the Small Account Policy (Accounts Below Minimum Account Balance) and Minimum Balance Fee

The automatic sale of Fund shares in accounts under $250 and the annual minimum balance fee described above do not apply to shareholders of Class Adv, Class Inst2, Class Inst3 and Class R shares; shareholders holding their shares through financial intermediary networked accounts; wrap fee and omnibus accounts; accounts with active monthly Systematic Investment Plans; certain qualified retirement plans; and health savings accounts. The automatic sale of Fund shares of accounts under the applicable minimum account balance does not apply to individual retirement plans.

Small Account Policy — Financial Intermediary Networked and Wrap Fee Accounts

The Funds may automatically redeem, at any time, financial intermediary networked accounts and wrap fee accounts that have account balances of $20 or less or have less than one share.

For shares purchased and held for your benefit through a financial intermediary, the Funds may instruct the intermediary to automatically sell your Fund shares if the transaction can be operationally administered by the intermediary.

Information Sharing Agreements

As required by Rule 22c-2 under the 1940 Act, the Funds or certain of their service providers will enter into information sharing agreements with financial intermediaries, including participating life insurance companies and financial intermediaries that sponsor or offer retirement plans through which shares of the Funds are made available for purchase. Pursuant to Rule 22c-2, financial intermediaries are required, upon request, to: (i) provide shareholder account and transaction information; and (ii) execute instructions from the Fund to restrict or prohibit further purchases of Fund shares by shareholders who have been identified by the Fund as having engaged in transactions that violate the Fund's excessive trading policies and procedures.

Excessive Trading Practices Policy

Right to Reject or Restrict Share Transaction Orders— The Fund is intended for investors with long-term investment purposes and is not intended as a vehicle for frequent trading activity (market timing) that is excessive. Investors should transact in Fund shares primarily for investment purposes. The Board has adopted excessive trading policies and procedures that are designed to deter excessive trading by investors (the Excessive Trading Policies and Procedures). The Fund discourages and does not accommodate excessive trading.

The Fund reserves the right to reject, without any prior notice, any purchase or exchange order for any reason, and will not be liable for any loss resulting from rejected orders. For example, the Fund may in its sole discretion restrict or reject a purchase or exchange order even if the transaction is not subject to the specific limitation described below if the Fund or its agents determine that accepting the order could interfere with efficient management of the Fund's portfolio or is otherwise contrary to the Fund's best interests. The Excessive Trading Policies and Procedures apply equally to purchase or exchange transactions communicated directly to the Transfer Agent and to those received by financial intermediaries.

Specific Buying and Exchanging Limitations — If the Fund detects that an investor has made two “material round trips” in any 28-day period, it will generally reject the investor's future purchase orders, including exchange purchase orders, involving any Fund.

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Columbia Acorn USA®

Buying, Selling and Exchanging Shares (continued)

For these purposes, a “round trip” is a purchase or exchange into the Fund followed by a sale or exchange out of the Fund, or a sale or exchange out of the Fund followed by a purchase or exchange into the Fund. A “material” round trip is one that is deemed by the Fund to be material in terms of its amount or its potential detrimental impact on the Fund. Independent of this limit, the Fund may, in its sole discretion, reject future purchase orders by any person, group or account that appears to have engaged in any type of excessive trading activity.

These limits generally do not apply to automated transactions or transactions by registered investment companies in a “fund-of-funds” structure. These limits do not apply to payroll deduction contributions by retirement plan participants, transactions initiated by a retirement plan sponsor or certain other retirement plan transactions consisting of rollover transactions, loan repayments and disbursements, and required minimum distribution redemptions. They may be modified or rescinded for accounts held by certain retirement plans to conform to plan limits, for considerations relating to the Employee Retirement Income Security Act of 1974 or regulations of the Department of Labor, and for certain asset allocation or wrap programs. Accounts known to be under common ownership or control generally will be counted together, but accounts maintained or managed by a common intermediary generally will not be considered to be under common ownership or control. The Fund reserves the right to modify these restrictions at any time without prior notice to shareholders. In addition, the Fund may, in its sole discretion, reinstate trading privileges that have been revoked under the Fund's Excessive Trading Policies and Procedures.

Limitations on the Ability to Detect and Prevent Excessive Trading Practices — The Fund takes various steps designed to detect and prevent excessive trading, including daily review of available shareholder transaction information. However, the Fund receives buy, sell or exchange orders through financial intermediaries, and cannot always know of or reasonably detect excessive trading that may be facilitated by financial intermediaries or by the use of the omnibus account arrangements they offer. Omnibus account arrangements are common forms of holding shares of mutual funds, particularly among certain financial intermediaries such as broker-dealers, retirement plans and variable insurance products. These arrangements often permit financial intermediaries to aggregate their clients' transactions and accounts, and in these circumstances, the identities of the financial intermediary clients that beneficially own Fund shares are often not known to the Fund.

Some financial intermediaries apply their own restrictions or policies to their clients’ transactions and accounts, which may be more or less restrictive than those described here. This may impact the Fund's ability to curtail excessive trading, even where it is identified. For these and other reasons, it is possible that excessive trading may occur despite the Fund's efforts to detect and prevent it.

Although these restrictions and policies involve judgments that are inherently subjective and may involve some selectivity in their application, the Fund seeks to act in a manner that it believes is consistent with the best interests of Fund shareholders in making any such judgments.

Risks of Excessive Trading — Excessive trading creates certain risks to the Fund's long-term shareholders and may create the following adverse effects:

■ negative impact on the Fund's performance;

■ potential dilution of the value of the Fund's shares;

■ interference with the efficient management of the Fund's portfolio, such as the need to maintain undesirably large cash positions, the need to use its line of credit or the need to buy or sell securities it otherwise would not have bought or sold;

■ losses on the sale of investments resulting from the need to sell securities at less favorable prices;

■ increased taxable gains to the Fund's remaining shareholders resulting from the need to sell securities to meet sell orders; and

■ increased brokerage and administrative costs.

To the extent that the Fund invests significantly in foreign securities traded on markets that close before the Fund's valuation time, it may be particularly susceptible to dilution as a result of excessive trading. Because events may occur after the close of foreign markets and before the Fund's valuation time that influence the value of foreign

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securities, investors may seek to trade Fund shares in an effort to benefit from their understanding of the value of foreign securities as of the Fund's valuation time. This is often referred to as price arbitrage. The Fund has adopted procedures designed to adjust closing market prices of foreign securities under certain circumstances to reflect what the Fund believes to be the fair value of those securities as of its valuation time. To the extent the adjustments do not work fully, investors engaging in price arbitrage may cause dilution in the value of the Fund's shares held by other shareholders.

The Columbia Acorn Funds may invest in thinly traded equity securities of small-capitalization companies. Because

these securities are often traded infrequently, investors may seek to trade Fund shares in an effort to benefit from their understanding of the value of these securities as of the Fund's valuation time. This is also a type of price arbitrage. Any such frequent trading strategies may interfere with efficient management of the Fund's portfolio to a greater degree than would be the case for mutual funds that invest only, or significantly, in highly liquid securities, in part because the Fund may have difficulty selling these particular investments at advantageous times or prices to satisfy large and/or frequent sell orders. Any successful price arbitrage may also cause dilution in the value of Fund shares held by non-redeeming shareholders.

Opening an Account and Placing Orders

We encourage you to consult with a financial advisor who can help you with your investment decisions and who can help you open an account. Once you have an account, you can buy, sell or exchange shares by contacting your financial advisor who will send your order to the Transfer Agent or your financial intermediary. As described below, once you have an account you can also communicate your orders directly to the Transfer Agent by mail, by telephone or online.

The Funds are generally available directly and through broker-dealers, banks and other financial intermediaries or institutions, and through certain qualified and non-qualified plans, wrap fee products or other investment products sponsored by financial intermediaries. You may buy, sell, or exchange shares through your financial intermediary. If you maintain your account directly with your financial intermediary, you must contact that agent to process your transaction.

Not all financial intermediaries offer the Funds (or all classes of Fund shares) and certain financial intermediaries that offer the Funds may not offer all Funds on all investment platforms or programs. Please consult with your financial intermediary to determine the availability of the Funds. If you set up an account at a financial intermediary that does not have, and is unable to obtain, a selling agreement with the Distributor, you will not be able to transfer Fund holdings to that account. In that event, you must either maintain your Fund holdings with your current financial intermediary or find another financial intermediary with a selling agreement.

Financial intermediaries that offer the Funds may charge you additional fees for the services they provide and they may have different policies that are not described in this prospectus. An investor transacting in a class of Fund shares without any front-end sales charge, CDSC, or other asset-based fee for sales or distribution, such as a Rule 12b-1 fee, may be required to pay a commission to the financial intermediary for effecting such transactions. The Funds are offered in a number of different share classes that have different fees and expenses and other features. Some differences in the policies of different financial intermediaries may include different minimum investment amounts, exchange privileges, Fund/class choices and cutoff times for investments. Additionally, recordkeeping, transaction processing and payments of distributions relating to your account may be performed by the financial intermediaries through which your shares of the Fund are held. Since the Fund (and its service providers) may not have a record of your account transactions, you should always contact the financial intermediary through which you purchased or at which you maintain your shares of the Fund to make changes to your account, to give instructions concerning your account, or to obtain information about your account. The Fund and its service providers, including the Distributor and the Transfer Agent, are not responsible for the failure of any financial intermediary to carry out its obligations to its customers.

The Fund may engage financial intermediaries to receive purchase, exchange and sell orders on its behalf. Accounts established directly with the Fund will be serviced by the Transfer Agent. The Funds, the Transfer Agent and the Distributor do not provide investment advice.

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Direct-At-Fund Accounts (Accounts Held Directly with the Fund)

Fund shares can be held in a variety of ways. You can hold Fund shares through an account established and held through the financial intermediary through which you purchased Fund shares, or you or your financial intermediary can establish an account directly with the Fund, in which case you will receive Fund account transaction confirmations and statements from the Transfer Agent, and not your financial intermediary (Direct-at-Fund Accounts). Direct-at-Fund Accounts include accounts held at the Transfer Agent that do not or no longer have a financial intermediary assigned to them.

To open a Direct-at-Fund Account, complete a Fund account application with your financial advisor or investment professional, and mail the account application to the Transfer Agent. Account applications may be obtained at columbiathreadneedleus.com or may be requested by calling 800.345.6611. Make your check payable to the Fund. You will be assessed a $15 fee for any checks rejected by your financial institution due to insufficient funds or other reasons. The Funds do not accept cash, credit card convenience checks, money orders, traveler's checks, starter checks, third or fourth party checks, or other cash equivalents.

Mail your check and completed application to the Transfer Agent at its regular or express mail address that can be found at the beginning of the section Choosing a Share Class. You may also use these addresses to request an exchange or redemption of Fund shares. When a written order to buy, sell or exchange shares is sent to the Transfer Agent, the share price used to fill the order is the next price calculated by the Fund after the Transfer Agent receives your transaction request in “good form” at its transaction processing center (i.e., the Fund’s express mail address), not the P.O. Box provided for regular mail delivery.

You will be sent a statement confirming your purchase and any subsequent transactions in your account. You will also be sent quarterly and annual statements detailing your transactions in the Fund and the other Funds you own under the same account. Duplicate quarterly account statements for the current year and duplicate annual statements for the most recent prior calendar year will be sent to you free of charge. Copies of year-end statements for prior years are available for a fee. Please contact the Transfer Agent for more information.

Written Transactions – Direct-at-Fund Accounts

If you have a Direct-at-Fund Account, you can communicate written buy, sell or exchange orders to the Transfer Agent at its address that can be found at the beginning of the section Choosing a Share Class. When a written order to buy, sell or exchange shares is sent to the Transfer Agent, the share price used to fill the order is the next price calculated by the Fund after the Transfer Agent receives your transaction request in “good form” at its transaction processing center (i.e., the Fund’s express mail address), not the P.O. Box provided for regular mail delivery.

Include in your transaction request letter: your name; the name of the Fund(s); your account number; the class of shares to be purchased, exchanged or sold; your SSN or other TIN; the dollar amount or number of shares you want to purchase, exchange or sell; specific instructions regarding delivery of any redemption proceeds or exchange destination (i.e., the Fund/class to be exchanged into); signature(s) of all registered account owner(s); and any special documents the Transfer Agent may require in order to process your order.

Corporate, trust or partnership accounts may need to send additional documents. Payment will be mailed to the address of record and made payable to the names listed on the account, unless your request specifies differently and is signed by all owners.

Telephone Transactions – Direct-at-Fund Accounts

For Class A, Class C, Class Inst, Class Inst3 and Class R shares, if you have a Direct-at-Fund Account, you may place orders to buy, sell or exchange shares by telephone through the Transfer Agent. To place orders by telephone, call 800.422.3737. Have your account number and SSN or TIN available when calling.

You can sell Fund shares via telephone and receive redemption proceeds: by electronic funds transfer via ACH, by wire, or by check to the address of record, subject to a maximum of $100,000 of shares per day, per Fund account. You can buy Fund shares via telephone by electronic funds transfer via ACH from your bank account up to a maximum

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of $100,000 of shares per day, per Fund account, or by wire from your bank account without a maximum. See below for more information regarding wire and electronic fund transfer transactions. Certain restrictions apply, so please call the Transfer Agent at 800.422.3737 for this and other information in advance of any need to transact via telephone.

Telephone orders may not be as secure as written orders. The Fund will take reasonable steps to confirm that telephone instructions are genuine. For example, we require proof of your identification before we will act on instructions received by telephone and may record telephone conversations. However, the Fund and its agents will not be responsible for any losses, costs or expenses resulting from an unauthorized telephone instruction when reasonable steps have been taken to confirm that telephone instructions are genuine. Telephone orders may be difficult to complete during periods of significant economic or market change or business interruption.

Online Transactions – Direct-at-Fund Accounts

For Class A, Class C, Class Inst, Class Inst3 and Class R shares, if you have a Direct-at-Fund Account, you may be able to place orders to buy, sell, or exchange shares online. Contact the Transfer Agent at 800.345.6611 for more information on certain account trading restrictions and the special sign-up procedures required for online transactions. You can also go to columbiathreadneedleus.com/investor/ to sign up for online transactions. The Transfer Agent has procedures in place to authenticate electronic orders you send through the internet. You will be required to accept the terms of an online agreement and to establish an online account and utilize a password in order to access online account services. You can sell a maximum of $100,000 of shares per day, per Fund account through your online account if you qualify for internet orders. Wire transactions are not permitted online.

Wire Transactions – Direct-at-Fund Accounts

If you hold a Direct-at-Fund Account, you may purchase or redeem Class A, Class C, Class Inst, Class Inst3 and Class R shares of a Fund by wiring money from (or to) your bank account to (or from) your Fund account. You must set up this feature prior to your request unless you are submitting your request in writing, which may require a Medallion Signature Guarantee. Please contact the Transfer Agent by calling 800.422.3737 to obtain the necessary forms and requirements. The Transfer Agent charges a fee for shares sold by wire. The Transfer Agent may waive the fee for certain accounts. In the case of a redemption, the receiving bank may charge an additional fee. The minimum amount that can be redeemed by wire is $500. When selling Fund shares via a telephone request, the maximum amount that can be redeemed via wire transfer is $100,000 per day, per Fund account. Wire transactions are not permitted online.

Electronic Funds Transfer via ACH – Direct-at-Fund Accounts

If you hold a Direct-at-Fund Account, you may purchase or redeem Class A, Class C, Class Inst, Class Inst3 and Class R shares of a Fund by electronically transferring money via Automated Clearing House (ACH) from (or to) your bank account to (or from) your Fund account subject to a maximum of $100,000 of shares per day, per Fund account. You must set up this feature prior to your request, unless you are submitting your request in writing, which may require a Medallion Signature Guarantee. Please contact the Transfer Agent by calling 800.422.3737 to obtain the necessary forms and requirements. Your bank may take up to three business days to post an electronic funds transfer to (or from) your Fund account.

Buying Shares

Eligible Investors

Class A Shares

Class A shares are available to the general public for investment.

Class Adv Shares

Class Adv shares are available only to (i) omnibus retirement plans, including self-directed brokerage accounts within omnibus retirement plans that clear through institutional no transaction fee (NTF) platforms, (ii) trust companies or similar institutions, (iii) broker-dealers, banks, trust companies and similar institutions that clear Fund share

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transactions for their client or customer investment advisory or similar accounts through designated financial intermediaries and their mutual fund trading platforms that have been granted specific written authorization from the Transfer Agent with respect to Class Adv eligibility apart from selling, servicing or similar agreements, (iv) 501(c)(3) charitable organizations, (v) 529 plans, (vi) health savings accounts, (vii) investors participating in a fee-based advisory program sponsored by a financial intermediary or other entity that is not compensated by the Fund for those services, other than payments for shareholder servicing or sub-accounting performed in place of the Transfer Agent, and (viii) commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Adv shares within such platform.

Class C Shares

Class C shares are available to the general public for investment, except that Direct-at-Fund Accounts that do not have a financial intermediary assigned to them are not permitted to purchase Class C shares; Class C share purchase orders received on or after such date from Direct-at-Fund Accounts that do not have a financial intermediary assigned to the account will automatically be invested in Class A shares of the same Fund.

Class Inst Shares

Class Inst shares are available only to the categories of eligible investors described below under Class Inst Shares Minimum Initial Investments. Financial intermediaries that clear Fund share transactions through designated financial intermediaries and their mutual fund trading platforms that were given specific written notice from the Transfer Agent of the termination, effective March 29, 2013, of their eligibility for new purchases of Class Inst shares and omnibus retirement plans are not permitted to establish new Class Inst accounts, subject to certain exceptions described below.

Omnibus retirement plans that opened and, subject to certain exceptions, funded a Class Inst account with the Fund as of the close of business on March 28, 2013 and have continuously held Class Inst shares in such account after such date (each, a grandfathered plan), may generally continue to make additional purchases of Class Inst shares, open new Class Inst accounts and add new participants. In addition, an omnibus retirement plan affiliated with a grandfathered plan may, in the sole discretion of the Distributor, open new Class Inst accounts in a Fund if the affiliated plan opened a Class Inst account on or before March 28, 2013. If an omnibus retirement plan invested in Class Inst shares changes recordkeepers after March 28, 2013, any new accounts established for that plan may not be established in Class Inst shares, but such a plan may establish new accounts in a different share class for which the plan is eligible.

Accounts of financial intermediaries (other than omnibus retirement plans, which are discussed above) that clear Fund share transactions for their client or customer accounts through designated financial intermediaries and their mutual fund trading platforms that received specific written notice from the Transfer Agent of the termination, effective March 29, 2013, of their eligibility for new purchases of Class Inst shares will not be permitted to establish new Class Inst accounts or make additional purchases of Class Inst shares (other than through reinvestment of distributions). Any such account may, at its holder’s option, exchange Class Inst shares of a Fund, without the payment of a sales charge, for Class A shares of the same Fund.

Class Inst2 Shares

Class Inst2 shares are available only to (i) certain registered investment advisers and family offices that clear Fund share transactions for their client or customer accounts through designated financial intermediaries and their mutual fund trading platforms that have been granted specific written authorization from the Transfer Agent with respect to Class Inst2 eligibility apart from selling, servicing or similar agreements; (ii) omnibus retirement plans; (iii) health savings accounts, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst2 shares within such platform and that Fund shares are held in an omnibus account; and (iv) institutional investors that are clients of the Columbia Threadneedle Global Institutional Distribution Team that invest in Class Inst2 shares for their own account through platforms approved by the Distributor or an affiliate thereof to offer and/or service Class Inst2 shares within such platform. Prior to November 8, 2012, Class Inst2

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shares were closed to new investors and new accounts, subject to certain exceptions. Existing shareholders who do not satisfy the new eligibility requirements for investment in Class Inst2 may not establish new Class Inst2 accounts but may continue to make additional purchases of Class Inst2 shares in accounts opened and funded prior to November 8, 2012; provided, however, that investment advisory programs and similar programs that opened a Class Inst2 account as of May 1, 2010, and continuously hold Class Inst2 shares in such account after such date, may generally not only continue to make additional purchases of Class Inst2 shares but also open new Class Inst2 accounts for such pre-existing programs and add new shareholders in the program.

Class Inst3 Shares

Class Inst3 shares are available to: (i) group retirement plans that maintain plan-level or omnibus accounts with the Fund (through the Transfer Agent); (ii) institutional investors that are clients of the Columbia Threadneedle Global Institutional Distribution Team that invest in Class Inst3 shares for their own account through platforms approved by the Distributor or an affiliate thereof to offer and/or service Class Inst3 shares within such platform; (iii) collective trust funds; (iv) affiliated or unaffiliated mutual funds (e.g., funds operating as funds-of-funds); (v) fee-based platforms of financial intermediaries (or the clearing intermediary that they trade through) that have an agreement with the Distributor or an affiliate thereof that specifically authorizes the financial intermediary to offer and/or service Class Inst3 shares within such platform, provided also that Fund shares are held in an omnibus account; (vi) commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst3 shares within such platform and that Fund shares are held in an omnibus account; (vii) health savings accounts, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst3 shares within such platform and that Fund shares are held in an omnibus account; and (viii) bank trust departments, subject to an agreement with the Distributor that specifically authorizes offering Class Inst3 shares and provided that Fund shares are held in an omnibus account. In each case above where noted that Fund shares are required to be held in an omnibus account, the Distributor may, in its discretion, determine to waive this requirement.

Class R Shares

Class R shares are available only to eligible health savings accounts sponsored by third party platforms, including those sponsored by Ameriprise Financial affiliates, eligible retirement plans and, in the sole discretion of the Distributor, other types of retirement accounts held through platforms maintained by financial intermediaries approved by the Distributor. Eligible retirement plans include any retirement plan other than individual 403(b) plans. Class R shares are generally not available for investment through retail nonretirement accounts, traditional and Roth IRAs, Coverdell Education Savings Accounts, SEPs, SAR-SEPs, Simple IRAs or 529 tuition programs. Contact the Transfer Agent or your retirement plan or health savings account administrator for more information about investing in Class R shares.

Additional Eligible Investors

In addition, the Distributor, in its sole discretion, may accept investments in any share class from investors other than those listed in this prospectus, and may also waive certain eligibility requirements for operational and other reasons, including but not limited to any requirement to maintain Fund shares in networked or omnibus accounts.

Minimum Initial Investments

The table below shows the Fund’s minimum initial investment requirements, which may vary by class and type of account.

The Fund reserves the right to redeem your shares if your account falls below the Fund’s minimum initial investment requirement.

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Minimum Initial Investments
	Minimum Initial Investment(a)	Minimum Initial Investment for Accounts with Systematic Investment Plans
For all classes and account types except those listed below	$2,000	$100
Individual Retirement Accounts for all classes except those listed below	$1,000	$100
Group retirement plans	None	N/A
Class Adv and Class Inst	$0, $1,000 or $2,000(b)	$100(b)
Class Inst2 and Class R	None	N/A
Class Inst3	$0, $1,000, $2,000 or $1 million(c)	$100(c)

(a) If your Class A, Class Adv, Class C, Class Inst, or Class Inst3 shares account balance falls below the minimum initial investment amount for any reason, including a market decline, you may be asked to increase it to the minimum initial investment amount or establish a monthly Systematic Investment Plan. If you do not do so, your account will be subject to a $20 annual low balance fee and/or shares may be automatically redeemed and the proceeds mailed to you if the account falls below the minimum account balance. See Buying, Selling and Exchanging Shares — Transaction Rules and Policies above. There is no minimum initial investment in Class A shares for accounts held in an omnibus account on a mutual fund only platform offered through your financial intermediary.

(b) The minimum initial investment in Class Adv shares is $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts) for commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customers, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Adv shares within such platform; for all other eligible Class Adv share investors (see Buying Shares – Eligible Investors – Class Adv Shares above), there is no minimum initial investment. The minimum initial investment amount for Class Inst shares is $0, $1,000 or $2,000 depending upon the category of eligible investor. See — Class Inst Shares Minimum Initial Investments below. The minimum initial investment amount for Systematic Investment Plan accounts is the same as the amount set forth in the first two rows of the table, as applicable.

(c) There is no minimum initial investment in Class Inst3 shares for: group retirement plans that maintain plan-level or omnibus accounts with the Fund; collective trust funds; affiliated or unaffiliated mutual funds (e.g., funds operating as funds-of-funds); and fee -based platforms of financial intermediaries (or the clearing intermediary that they trade through) that have an agreement with the Distributor or an affiliate thereof that specifically authorizes the financial intermediary to offer and/or service Class Inst3 shares within such platform and Fund shares are held in an omnibus account. The minimum initial investment in Class Inst3 shares is $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts) for commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst3 shares within such platform and Fund shares are held in an omnibus account. The minimum initial investment in Class Inst3 shares is $1 million, unless waived in the discretion of the Distributor, for the following investors: institutional investors that are clients of the Columbia Threadneedle Global Institutional Distribution Team that invest in Class Inst3 shares for their own account through platforms approved by the Distributor or an affiliate thereof to offer and/or service Class Inst3 shares within such platform; and bank trust departments, subject to an agreement with the Distributor that specifically authorizes offering Class Inst3 shares and provided that Fund shares are held in an omnibus account. The Distributor may, in its discretion, waive the $1 million minimum initial investment required for these Class Inst3 investors. In each case above where noted that Fund shares are required to be held in an omnibus account, the Distributor, may, in its discretion, determine to waive this requirement.

Additional Information about Minimum Initial Investments

The minimum initial investment requirements may be waived for accounts that are managed by an investment professional, or for accounts held in approved discretionary or non-discretionary wrap programs. The Distributor, in its sole discretion, may also waive minimum initial investment requirements for other account types.

Minimum investment and related requirements may be modified at any time, with or without prior notice. If your account is closed and then re-opened with a Systematic Investment Plan, your account must meet the then-current applicable minimum initial investment.

Class Inst Shares Minimum Initial Investments

There is no minimum initial investment in Class Inst shares for the following categories of eligible investors:

■ Any health savings account sponsored by a third party platform.

■ Any investor participating in an account sponsored by a financial intermediary or other entity (that provides services to the account) that is paid a fee-based advisory fee by the investor and that is not compensated by the Fund for those services, other than payments for shareholder servicing or sub-accounting performed in place of the Transfer Agent.

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■ Any commissionable brokerage account, if a financial intermediary has received a written approval from the Distributor to waive the minimum initial investment in Class Inst shares.

■ Any Trustee (or family member) of Columbia Acorn Trust.

■ Any employee (or family member) of the Investment Manager.

The minimum initial investment in Class Inst shares for the following categories of eligible investors is $1,000:

■ Individual retirement accounts (IRAs) on commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst shares within such platform.

■ Any current employee of Columbia Management Investment Advisers LLC, the Distributor or the Transfer Agent and immediate family members of any of the foregoing who share the same address are eligible to invest in Class Inst shares through an individual retirement account (IRA). If you maintain your account with a financial intermediary, you must contact that financial intermediary each time you seek to purchase shares to notify them that you qualify for Class Inst shares. If Class Inst shares are not available at your financial intermediary, you may consider opening a Direct-at-Fund Account. It is your obligation to advise your financial intermediary or (in the case of Direct-at-Fund Accounts) the Transfer Agent that you qualify for Class Inst shares; be prepared to provide proof thereof.

The minimum initial investment in Class Inst shares for the following categories of eligible investors is $2,000:

■ Investors (except investors in individual retirement accounts (IRAs)) who purchase Fund shares through commissionable brokerage platforms where the financial intermediary holds the shares in an omnibus account and, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst shares within such platform.

■ Any current employee of Columbia Management Investment Advisers LLC, the Distributor or the Transfer Agent and immediate family members of any of the foregoing who share the same address are eligible to invest in Class Inst shares (other than individual retirement accounts (IRAs), for which the minimum initial investment is $1,000). If you maintain your account with a financial intermediary, you must contact that financial intermediary each time you seek to purchase shares to notify them that you qualify for Class Inst shares. If Class Inst shares are not available at your financial intermediary, you may consider opening a Direct-at-Fund Account. It is your obligation to advise your financial intermediary or (in the case of Direct-at-Fund Accounts) the Transfer Agent that you qualify for Class Inst shares; be prepared to provide proof thereof.

■ Certain financial institutions and intermediaries, such as insurance companies, trust companies, banks, endowments, investment companies or foundations, buying shares for their own account, including Ameriprise Financial and its affiliates and/or subsidiaries.

■ Bank trust departments that assess their clients an asset-based fee.

■ Any trustee or director (or family member of a trustee or director) of a fund distributed by the Distributor (other than the Columbia Acorn Funds).

■ Certain other investors as set forth in more detail in the SAI.

Systematic Investment Plan

The Systematic Investment Plan allows you to schedule regular purchases via automatic transfers from your bank account to the Fund on a monthly, quarterly or semiannual basis. Contact the Transfer Agent or your financial intermediary to set up the plan. Systematic Investment Plans may not be available for all share classes. With the exception of Columbia Government Money Market Fund, Systematic Investment Plan purchases will be confirmed on your quarterly account statement. Columbia Government Money Market Fund Systematic Investment Plan purchases will be confirmed at the time of the purchase. If establishing a Systematic Investment Plan to reduce the initial fund minimum, the plan needs to be established monthly to avoid the small account fee.

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Dividend Diversification

Generally, you may automatically invest Fund distributions into the same class of shares (and in some cases certain other classes of shares) of another Fund without paying any applicable front-end sales charge. Call the Transfer Agent at 800.345.6611 for details. The ability to invest distributions from one Fund to another Fund may not be available to accounts held at all financial intermediaries.

Other Purchase Rules You Should Know

■ Once the Transfer Agent or your financial intermediary receives your purchase order in “good form,” your purchase will be made at the Fund’s next calculated public offering price per share, which is the NAV per share plus any sales charge that applies (i.e., the trade date).

■ Once the Fund receives your purchase request in “good form,” you cannot cancel it after the market closes.

■ You generally buy Class A shares at the public offering price per share because purchases of these share classes are generally subject to a front-end sales charge.

■ You buy Class Adv, Class C, Class Inst, Class Inst2, Class Inst3 and Class R shares at NAV per share because no front-end sales charge applies to purchases of these share classes.

■ The Distributor and the Transfer Agent reserve the right to cancel your order request if the Fund does not receive payment within two business days of receiving your purchase order request. The Fund will return any payment received for orders that have been cancelled, but no interest will be paid on that money.

■ Financial intermediaries are responsible for sending your purchase orders to the Transfer Agent and ensuring that the Fund receives your money on time.

■ Shares purchased are recorded on the books of the Fund. The Fund does not issue certificates.

■ You generally may make a purchase only into a Fund that is accepting investments.

Please also read Appendix A and contact your financial intermediary for more information regarding any reductions and/or waivers described therein.

Selling Shares

When you sell shares, the amount you receive may be more or less than the amount you invested. Your sale price will be the next NAV calculated after your request is received in “good form,” (i.e., the trade date) minus any applicable CDSC.

Systematic Withdrawal Plan

The Systematic Withdrawal Plan allows you to schedule regular redemptions from your account any business day on a monthly, quarterly or semiannual basis. Currently, Systematic Withdrawal Plans are generally available for Class A, Class Adv, Class C, Class Inst, Class Inst2, and Class Inst3 share accounts. Contact the Transfer Agent or your financial intermediary to set up the plan. To set up the plan, your account balance must meet the class minimum initial investment amount. A Systematic Withdrawal Plan cannot be set up on an account that already has a Systematic Investment Plan established. Note that a Medallion Signature Guarantee may be required if this service is established after your Fund account is opened.

You can choose to receive your withdrawals via check or direct deposit into your bank account. The Fund will deduct any applicable CDSC from the withdrawals before sending redemption proceeds to you. You can cancel the plan by giving the Fund 30 days’ notice in writing or by calling the Transfer Agent at 800.422.3737. It’s important to remember that if you withdraw more than your investment in the Fund is earning, you'll eventually withdraw your entire investment.

Satisfying Fund Redemption Requests

When you sell your Fund shares, the Fund is effectively buying them back from you. This is called a redemption. Except as noted below with respect to newly purchased shares, the Fund typically expects to send you payment for your shares within two business days after your trade date. The Fund can suspend redemptions and/or delay

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Buying, Selling and Exchanging Shares (continued)

payment of redemption proceeds for up to seven days. The Fund can also suspend redemptions and/or delay payment of redemption proceeds in excess of seven days under certain circumstances, including when the NYSE is closed or trading thereon is restricted or during emergency or other circumstances, including as determined by the SEC.

The Fund typically seeks to satisfy redemption requests from cash or cash equivalents held by the Fund, from the proceeds of orders to purchase Fund shares or from the proceeds of sales of Fund holdings effected in the normal course of managing the Fund. However, the Fund may have to sell Fund holdings, including in down markets, to meet heavier than usual redemption requests. For example, under stressed or abnormal market conditions or circumstances, including circumstances adversely affecting the liquidity of the Fund’s investments, the Fund may be more likely to be forced to sell Fund holdings to meet redemptions than under normal market circumstances. In these situations, the Fund’s portfolio managers may have to sell Fund holdings that would not otherwise be sold because, among other reasons, the current price to be received is less than the value of the holdings perceived by the Fund’s portfolio managers. The Fund may also, under certain circumstances (likely under stressed or abnormal market conditions or circumstances), borrow money under a credit facility to which the Fund and certain other Columbia Funds are parties. The Fund and the other Columbia Funds are limited as to the amount that each may individually and collectively borrow under the credit facility. As a result, borrowings available to the Fund under the credit facility might be insufficient, alone or in combination with the other strategies described herein, to satisfy Fund redemption requests. Please see About Fund Investments – Borrowings in the SAI for more information about the credit facility. The Fund is also limited in the total amount it may borrow. Please see About Fund Investments – Fundamental and Non-Fundamental Investment Policies in the SAI for more information about borrowing.

In addition, the Fund reserves the right to honor redemption orders in whole or in part with in-kind distributions of Fund portfolio securities instead of cash. Such in-kind distributions typically represent a pro-rata portion of Fund portfolio assets subject to adjustments (e.g., for non-transferable securities, round lots, and derivatives, if any). In the event the Fund distributes portfolio securities in kind, you may incur brokerage and other transaction costs associated with converting the portfolio securities you receive into cash. Also, the portfolio securities you receive may increase or decrease in value after they are distributed but before you convert them into cash. For U.S. federal income tax purposes, redemptions paid in securities are generally treated the same as redemptions paid in cash. The Trust has elected to be governed by Rule 18f-1 under the 1940 Act, which means that for each redeeming shareholder, the first $250,000, or 1% of the Fund's net asset value, whichever is less, will be paid in cash or cash equivalents and the remainder may be paid in kind.

While the Fund is not required (and may refuse in its discretion) to pay a redemption with an in-kind distribution of Fund portfolio securities and reserves the right to pay the redemption proceeds in cash, if you wish to request an in-kind redemption, please call the Transfer Agent at 800.345.6611. As a result of the operational steps needed to coordinate with the redeeming shareholder’s custodian, in-kind redemptions typically take several weeks to complete after a redemption request is received. The Fund and the redeeming shareholder will typically agree upon a redemption date. Since the Fund’s NAV may fluctuate during this time, the Fund’s NAV may be lower on the agreed-upon redemption date than on an earlier date on which the investment could have been redeemed for cash.

Redemption of Newly Purchased Shares

You may not redeem shares for which the Fund has not yet received payment. Shares purchased by check or electronically by ACH when the purchase payment is not guaranteed will be considered in “good form” for redemption only after they have been held in your account for 6 calendar days after the trade date of the purchase (Collected Shares). If you request a redemption for an amount that, based on the NAV next calculated after your redemption request is received, includes any shares that are not yet Collected Shares, the Fund will only process the redemption up to the amount of the value of Collected Shares available in your account. You must submit a new redemption request if you wish to redeem those shares that were not yet Collected Shares at the time the original redemption request was received by the Fund.

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Buying, Selling and Exchanging Shares (continued)

Other Redemption Rules You Should Know

■ Once the Transfer Agent or your financial intermediary receives your redemption order in “good form,” your shares will be sold at the Fund’s next calculated NAV per share (i.e., the trade date). Any applicable CDSC will be deducted from the amount you're selling and the balance will be remitted to you.

■ Once the Fund receives your redemption request in “good form,” you cannot cancel it after the market closes.

■ The Distributor, in its sole discretion, reserves the right to liquidate Fund shares (of any class of the Fund) held in an omnibus account of a financial intermediary that clears Fund share transactions through a clearing intermediary or platform that charges certain maintenance fees to the Fund if the value of the omnibus account, at the Fund share class (i.e., CUSIP) level, falls below $100,000 (a CUSIP Liquidation Event). The Distributor will provide at least 90 days’ notice of a CUSIP Liquidation Event to financial intermediaries with impacted omnibus accounts. Shareholders invested in the Fund through such omnibus accounts can request through their financial intermediary a tax-free exchange to Class A shares or shareholders can consider holding their Fund shares in a Direct-at-Fund Account, provided requirements to transfer the account are fulfilled. You should discuss your options with your financial intermediary.

■ If you sell your shares that are held in a Direct-at-Fund Account, we will normally send the redemption proceeds by mail or electronically transfer them to your bank account the next business day after the trade date. Note that your bank may take up to three business days to post an electronic funds transfer from your account.

■ If you sell your shares through a financial intermediary, the Funds will normally send the redemption proceeds to your financial intermediary within two business days after the trade date.

■ No interest will be paid on uncashed redemption checks.

■ Other restrictions may apply to retirement accounts. For information about these restrictions, contact your retirement plan administrator.

■ For broker-dealer and wrap fee accounts: The Fund reserves the right to redeem your shares if your account falls below the Fund's minimum initial investment requirement. The Fund will notify your broker-dealer prior to redeeming shares, and will provide details on how to avoid such redemption.

■ Also keep in mind the Funds' Small Account Policy, which is described above in Buying, Selling and Exchanging Shares — Transaction Rules and Policies.

Exchanging Shares

You can generally sell shares of your Fund to buy shares of another Fund (subject to eligibility requirements), in what is called an exchange. You should read the prospectus of, and make sure you understand the investment objective, principal investment strategies, risks, fees and expenses of, the Fund into which you are exchanging. Although the Funds allow certain exchanges from one share class to another share class with higher expenses, you should consider the expenses of each class before making such an exchange. Please see Same-Fund Exchange Privilege below for more information.

You will be subject to a sales charge if, in a Direct-at-Fund Account, you exchange shares that have not previously paid a sales charge, including from Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia U.S. Treasury Index Fund or any other Columbia Fund that does not charge a front-end sales charge, into a Columbia Fund that does assess a sales charge. If you hold your Fund shares through certain financial intermediaries, you may have limited exchangeability among the Funds. Please contact your financial intermediary for more information.

Systematic Exchanges

You may buy Class A, Class C, Class Inst and Class Inst3 shares of a Fund by exchanging each month from another Fund for shares of the same class of the Fund at no additional cost, subject to the following exchange amount minimums: $50 each month for individual retirement accounts (i.e., tax qualified accounts); and $100 each month for non-retirement accounts. Contact the Transfer Agent or your financial intermediary to set up the plan.

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Buying, Selling and Exchanging Shares (continued)

Exchanges will continue as long as your balance in the Fund you are exchanging shares from is sufficient to complete the systematic monthly exchange, subject to the Funds' Small Account Policy described above in Buying, Selling and Exchanging Shares — Transaction Rules and Policies. You may terminate the program or change the amount you would like to exchange (subject to the $50 and $100 minimum requirements noted immediately above) by calling the Transfer Agent at 800.345.6611.

Other Exchange Rules You Should Know

■ Exchanges are made at the NAV next calculated (plus any applicable sales charge) after your exchange order is received in “good form” (i.e., the trade date).

■ Once the Fund receives your exchange request in “good form,” you cannot cancel it after the market closes.

■ The rules for buying shares of a Fund generally apply to exchanges into that Fund, including, if your exchange creates a new Fund account, it must satisfy the minimum investment amount, unless a waiver applies.

■ Shares of the purchased Fund may not be used on the same day for another exchange or sale.

■ If you exchange shares from Class A shares of Columbia Government Money Market Fund to a non-money market Fund, any further exchanges must be between shares of the same class. For example, if you exchange from Class A shares of Columbia Government Money Market Fund into Class C shares of a non-money market Fund, you may not exchange from Class C shares of that non-money market Fund back to Class A shares of Columbia Government Money Market Fund or Class A shares of any other Fund.

■ A sales charge may apply when you exchange shares of a Fund that were not assessed a sales charge at the time you purchased such shares. If you invest through a Direct-at-Fund Account in Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund, Columbia U.S. Treasury Index Fund or any other Columbia Fund that does not impose a front-end sales charge and then you exchange into a Fund that does assess a sales charge, your transaction is subject to a front-end sales charge if you exchange into Class A shares and to a CDSC if you exchange into Class C shares of the Columbia Funds.

■ If you purchased Class A shares of a Columbia Fund that imposes a front-end sales charge (and you paid any applicable sales charge) and you then exchange those shares into Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund, Columbia U.S. Treasury Index Fund or any other Columbia Fund that does not impose a front-end sales charge, you may exchange that amount to Class A of another Fund in the future, including dividends earned on that amount, without paying a sales charge.

■ If your shares are subject to a CDSC, you will not be charged a CDSC upon the exchange of those shares. Any CDSC will be deducted when you sell the shares you received from the exchange. The CDSC imposed at that time will be based on the period that begins when you bought shares of the original Fund and ends when you sell the shares of the Fund you received from the exchange. Any applicable CDSC charged will be the CDSC of the original Fund.

■ You may make exchanges only into a Fund that is legally offered and sold in your state of residence. Contact the Transfer Agent or your financial intermediary for more information.

■ You generally may make an exchange only into a Fund that is accepting investments.

■ The Fund may change or cancel your right to make an exchange by giving the amount of notice required by regulatory authorities (generally 60 days for a material change or cancellation).

■ Unless your account is part of a tax-advantaged arrangement, an exchange for shares of another Fund is a taxable event, and you may recognize a gain or loss for tax purposes.

■ Changing your investment to a different Fund will be treated as a sale and purchase, and you will be subject to applicable taxes on the sale and sales charges on the purchase of the new Fund.

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Buying, Selling and Exchanging Shares (continued)

■ Class Inst shares of a Fund may be exchanged for Class A or Class Inst shares of another Fund. In certain circumstances, the front-end sales charge applicable to Class A shares may be waived on exchanges of Class Inst shares for Class A shares. See Buying, Selling and Exchanging Shares — Buying Shares — Eligible Investors — Class Inst Shares for details.

Same-Fund Exchange Privilege

Shareholders may be eligible to invest in other classes of shares of the same Fund, and may exchange their current shares for another share class if deemed eligible and offered by the Fund. Such same-Fund exchanges could include an exchange of one class for another with higher expenses. Before making such an exchange, you should consider the expenses of each class. Shareholders should contact their financial intermediaries to learn more about the details of the same-Fund exchange privilege. Exchanges out of Class A and Class C shares will be subject to any applicable CDSC. Financial intermediaries that have a customized arrangement with regard to CDSCs are detailed in Appendix A.

Exchanges out of Class C shares to another share class of the same Fund are not permissible on Direct-at-Fund Accounts, except that the Transfer Agent seeks to convert Class C shares as soon as administratively feasible to Class A shares of the same Fund for Direct-at-Fund Accounts that do not or no longer have a financial intermediary assigned to them. Direct-at-Fund Accounts that do not have a financial intermediary assigned to them are not permitted to purchase Class C shares. Class C share purchase orders received by Direct-at-Fund Accounts that do not have a financial intermediary assigned to the account will automatically be invested in Class A shares of the same Fund. Exchanges out of Class C shares to another share class of the same Fund within commissionable brokerage accounts are permitted only (1) when the shareholder moves from a commissionable brokerage account to a fee-based advisory program or (2) when the exchange is part of a share class conversion (or a similar multiple shareholder transaction event) instituted by a financial intermediary and such conversion or similar type event is preapproved by the Distributor.

Ordinarily, shareholders will not recognize a gain or loss for U.S. federal income tax purposes upon a same-Fund exchange. You should consult your tax advisor about your particular exchanges.

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Distributions and Taxes

Distributions to Shareholders

A mutual fund can make money two ways:

■ It can earn income on its investments. Examples of fund income are interest paid on money market instruments and bonds, and dividends paid on common stocks.

■ A mutual fund can also have capital gains if the value of its investments increases. While a fund continues to hold an investment, any gain is generally unrealized. If the fund sells an investment, it generally will realize a capital gain if it sells that investment for a higher price than its adjusted cost basis, and will generally realize a capital loss if it sells that investment for a lower price than its adjusted cost basis. Capital gains and losses are either short-term or long-term, depending on whether the fund holds the securities for one year or less (short-term) or more than one year (long-term).

Mutual funds make payments of fund earnings to shareholders, distributing them among all shareholders of the fund. As a shareholder, you are entitled to your portion of a fund's distributed income, including capital gains. Reinvesting your distributions buys you more shares of a fund — which lets you take advantage of the potential for compound growth. Putting the money you earn back into your investment means it, in turn, may earn even more money (or be exposed to additional losses, if the Fund earns a negative return). Over time, the power of compounding has the potential to significantly increase the value of your investment. There is no assurance, however, that you'll earn more money if you reinvest your distributions rather than receive them in cash.

The Fund intends to pay out, in the form of distributions to shareholders, a sufficient amount of its income and gains so that the Fund will qualify for treatment as a regulated investment company and generally will not have to pay any federal excise tax. The Fund generally intends to distribute any net realized capital gain (whether long-term or short-term gain) at least once a year. Normally, the Fund will declare and pay distributions of net investment income according to the following schedule:

Declaration and Distribution Schedule
Declarations	Semiannually
Distributions	Semiannually

The Fund may declare or pay distributions of net investment income more frequently.

Different share classes of the Fund usually pay different net investment income distribution amounts, because each class has different expenses. Each time a distribution is made, the NAV per share of the share class is reduced by the amount of the distribution.

The Fund generally pays cash distributions within five business days after the distribution was declared (or, if the Fund declares distributions daily, within five business days after the end of the month in which the distribution was declared). If you sell all of your shares after the record date, but before the payment date, for a distribution, you'll normally receive that distribution in cash within five business days after the sale was made.

The Fund will automatically reinvest distributions in additional shares of the same share class of the Fund unless you inform us you want to receive your distributions in cash (the financial intermediary through which you purchased shares may have different policies). You can do this by contacting the Funds at the addresses and telephone numbers listed at the beginning of the section entitled Choosing a Share Class. No sales charges apply to the purchase or sale of such shares.

For accounts held directly with the Fund (through the Transfer Agent), distributions of $10 or less will automatically be reinvested in additional Fund shares only. If you elect to receive distributions by check and the check is returned as undeliverable, all subsequent distributions will be reinvested in additional shares of the Fund.

Unless you are a tax-exempt investor or holding Fund shares through a tax-advantaged account (such as a 401(k) plan or IRA), you should consider avoiding buying Fund shares shortly before the Fund makes a distribution (other than distributions of net investment income that are declared daily) of net investment income or net realized capital gain, because doing so can cost you money in taxes to the extent the distribution consists of taxable income or gains. This is because you will, in effect, receive part of your purchase price back in the distribution. This is known as

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Distributions and Taxes (continued)

“buying a dividend.” To avoid “buying a dividend,” before you invest check the Fund's distribution schedule, which is available at the Funds' website and/or by calling the Funds' telephone number listed at the beginning of the section entitled Choosing a Share Class.

Taxes

You should be aware of the following considerations applicable to the Fund:

■ The Fund intends to qualify and to be eligible for treatment each year as a regulated investment company. A regulated investment company generally is not subject to tax at the fund level on income and gains from investments that are distributed to shareholders. However, the Fund's failure to qualify for treatment as a regulated investment company would result in Fund-level taxation, and consequently, a reduction in income available for distribution to you and in the NAV of your shares. Even if the Fund qualifies for treatment as a regulated investment company, the Fund may be subject to federal excise tax on certain undistributed income or gains.

■ Otherwise taxable distributions generally are taxable to you when paid, whether they are paid in cash or automatically reinvested in additional Fund shares. Dividends paid in January are deemed paid on December 31 of the prior year if the dividend was declared and payable to shareholders of record in October, November, or December of such prior year.

■ Distributions of the Fund's ordinary income and net short-term capital gain, if any, generally are taxable to you as ordinary income. Distributions of the Fund's net long-term capital gain, if any, generally are taxable to you as long-term capital gain. Whether capital gains are long-term or short-term is determined by how long the Fund has owned the investments that generated them, rather than how long you have owned your shares. Certain events may require the Fund to sell significant amounts of appreciated securities, and make large capital gain dividends relative to the Fund’s NAV. Such events may include large net shareholder redemptions, portfolio re-balancing or fund mergers. The Fund generally provides estimates of expected capital gain dividends (if any) prior to the distribution on columbiathreadneedleus.com.

■ From time to time, a distribution from the Fund could constitute a return of capital. A return of capital is a return of an amount of your original investment and is not a distribution of income or capital gain from the Fund. Therefore, a return of capital is not taxable to you so long as the amount of the distribution does not exceed your tax basis in your Fund shares. A return of capital reduces your tax basis in your Fund shares, with any amounts exceeding such basis generally taxable as capital gain.

■ If you are an individual and you meet certain holding period and other requirements for your Fund shares, a portion of your distributions may be treated as “qualified dividend income” taxable at the lower net long-term capital gain rates instead of the higher ordinary income rates. Qualified dividend income is income attributable to the Fund's dividends received from certain U.S. and foreign corporations, as long as the Fund meets certain holding period and other requirements for the stock producing such dividends.

■ Certain high-income individuals (as well as estates and trusts) are subject to a 3.8% tax on net investment income. For individuals, the 3.8% tax applies to the lesser of (1) the amount (if any) by which the taxpayer's modified adjusted gross income exceeds certain threshold amounts or (2) the taxpayer's “net investment income.”

■ Certain derivative instruments when held in the Fund's portfolio subject the Fund to special tax rules, the effect of which may be to, among other things, accelerate income to the Fund, defer Fund losses, cause adjustments in the holding periods of Fund portfolio securities, or convert capital gains into ordinary income, short-term capital losses into long-term capital losses or long-term capital gains into short-term capital gains. These rules could therefore affect the amount, timing and/or character of distributions to shareholders.

■ Generally, a Fund realizes a capital gain or loss on an option when the option expires, or when it is exercised, sold or otherwise terminated. However, if an option is a “section 1256 contract,” which includes most traded options on a broad-based index, and the Fund holds such option at the end of its taxable year, the Fund is deemed to sell such option at fair market value at such time and recognize any gain or loss thereon, which is generally deemed to be 60% long-term and 40% short-term capital gain or loss, as described further in the SAI.

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Distributions and Taxes (continued)

■ A sale, redemption or exchange of Fund shares is a taxable event. This includes redemptions where you are paid in securities. Your sales, redemptions and exchanges of Fund shares (including those paid in securities) usually will result in a taxable capital gain or loss to you, equal to the difference between the amount you receive for your shares (or are deemed to have received in the case of exchanges) and your adjusted tax basis in the shares, which is generally the amount you paid (or are deemed to have paid in the case of exchanges) for them. Any such capital gain or loss generally will be long-term capital gain or loss if you have held your Fund shares for more than one year at the time of sale or exchange. In certain circumstances, capital losses may be converted from short-term to long-term; in other circumstances, capital losses may be disallowed under the “wash sale” rules.

■ For sales, redemptions and exchanges of shares that were acquired in a non-qualified account after 2011, the Fund generally is required to report to shareholders and the Internal Revenue Service (IRS) cost basis information with respect to those shares. The Fund uses average cost basis as its default method of calculating cost basis. For more information regarding average cost basis reporting, other available cost basis methods, and selecting or changing to a different cost basis method, please see the SAI, columbiathreadneedleus.com, or contact the Fund at 800.345.6611. If you hold Fund shares through a financial intermediary (e.g., a brokerage firm), you should contact your financial intermediary to learn about its cost basis reporting default method and the reporting elections available to your account.

■ The Fund is required by federal law to withhold tax on any taxable or tax-exempt distributions and redemption proceeds paid to you (including amounts paid to you in securities and amounts deemed to be paid to you upon an exchange of shares) if: you have not provided a correct TIN or have not certified to the Fund that withholding does not apply, the IRS has notified us that the TIN listed on your account is incorrect according to its records, or the IRS informs the Fund that you are otherwise subject to backup withholding.

 FUNDamentals

Taxes

The information provided above is only a summary of how U.S. federal income taxes may affect your investment in the Fund. It is not intended as a substitute for careful tax planning. Your investment in the Fund may have other tax implications. It does not apply to certain types of investors who may be subject to special rules, including foreign or tax-exempt investors or those holding Fund shares through a tax-advantaged account, such as a 401(k) plan or IRA. Please see the SAI for more detailed tax information. You should consult with your own tax advisor about the particular tax consequences to you of an investment in the Fund, including the effect of any foreign, state and local taxes, and the effect of possible changes in applicable tax laws.

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Financial Highlights

The financial highlights table is intended to help you understand the Fund’s financial performance for the past five fiscal years. Certain information reflects financial results for a single Fund share. Per share net investment income (loss) amounts are calculated based on average shares outstanding during the period. The total return in the table represents the rate that an investor would have earned (or lost) on an investment in the Fund assuming all dividends and distributions had been reinvested. Total return does not reflect payment of sales charges, if any. Total return and portfolio turnover are not annualized for periods of less than one year. The portfolio turnover rate is calculated without regard to purchase and sales transactions of short-term instruments and certain derivatives, if any. If such transactions were included, the Fund’s portfolio turnover rate might be higher. The names of certain share classes may have changed during the periods shown below (see Appendix S to the SAI for details). This information has been audited by PricewaterhouseCoopers LLP, an independent registered public accounting firm, whose report, along with the Fund’s financial statements, is included in the Fund’s annual report, which is available upon request. The independent registered public accounting firm’s report and the Fund’s financial statements are also incorporated by reference into the SAI.

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Financial Highlights (continued)

	Net asset value, beginning of period	Net investment income (loss)	Net realized and unrealized gain (loss)	Total from investment operations	Distributions from net investment income	Distributions from net realized gains	Total distributions to shareholders
Class A
Year Ended 12/31/2021	$13.58	(0.15)	1.20	1.05	(0.12)	(4.37)	(4.49)
Year Ended 12/31/2020	$11.69	(0.10)	2.76	2.66	—	(0.77)	(0.77)
Year Ended 12/31/2019	$10.28	(0.05)	3.14	3.09	(0.01)	(1.67)	(1.68)
Year Ended 12/31/2018	$12.48	(0.07)	(0.04)	(0.11)	—	(2.09)	(2.09)
Year Ended 12/31/2017	$14.95	(0.09)	2.84	2.75	—	(5.22)	(5.22)
Advisor Class
Year Ended 12/31/2021	$19.32	(0.16)	1.75	1.59	(0.13)	(4.41)	(4.54)
Year Ended 12/31/2020	$16.31	(0.10)	3.91	3.81	—	(0.80)	(0.80)
Year Ended 12/31/2019	$13.77	(0.03)	4.25	4.22	(0.01)	(1.67)	(1.68)
Year Ended 12/31/2018	$16.08	(0.05)	(0.09)	(0.14)	—	(2.17)	(2.17)
Year Ended 12/31/2017	$17.93	(0.06)	3.43	3.37	—	(5.22)	(5.22)
Class C(e)
Year Ended 12/31/2021	$18.14	(0.34)	1.64	1.30	(0.13)	(4.28)	(4.41)
Year Ended 12/31/2020	$16.47	(0.25)	3.60	3.35	—	(1.68)	(1.68)
Year Ended 12/31/2019	$18.07	(0.24)	5.32	5.08	—	(6.68)	(6.68)
Year Ended 12/31/2018	$26.22	(0.36)	0.17(f)	(0.19)	—	(7.96)	(7.96)
Year Ended 12/31/2017	$40.19	(0.52)	7.43	6.91	—	(20.88)	(20.88)
Institutional Class
Year Ended 12/31/2021	$17.90	(0.15)	1.62	1.47	(0.13)	(4.41)	(4.54)
Year Ended 12/31/2020	$15.17	(0.10)	3.63	3.53	—	(0.80)	(0.80)
Year Ended 12/31/2019	$12.90	(0.03)	3.98	3.95	(0.01)	(1.67)	(1.68)
Year Ended 12/31/2018	$15.21	(0.04)	(0.09)	(0.13)	—	(2.18)	(2.18)
Year Ended 12/31/2017	$17.20	(0.05)	3.28	3.23	—	(5.22)	(5.22)
Institutional 2 Class
Year Ended 12/31/2021	$19.50	(0.15)	1.77	1.62	(0.12)	(4.43)	(4.55)
Year Ended 12/31/2020	$16.46	(0.10)	3.95	3.85	—	(0.81)	(0.81)
Year Ended 12/31/2019	$13.87	(0.01)	4.28	4.27	(0.01)	(1.67)	(1.68)
Year Ended 12/31/2018	$16.21	(0.03)	(0.11)	(0.14)	—	(2.20)	(2.20)
Year Ended 12/31/2017	$18.02	(0.03)	3.44	3.41	—	(5.22)	(5.22)
Institutional 3 Class
Year Ended 12/31/2021	$19.74	(0.15)	1.81	1.66	(0.13)	(4.43)	(4.56)
Year Ended 12/31/2020	$16.65	(0.09)	4.00	3.91	—	(0.82)	(0.82)
Year Ended 12/31/2019	$14.01	(0.01)	4.33	4.32	(0.01)	(1.67)	(1.68)
Year Ended 12/31/2018	$16.36	(0.02)	(0.11)	(0.13)	—	(2.22)	(2.22)
Year Ended 12/31/2017	$18.14	(0.03)	3.47	3.44	—	(5.22)	(5.22)

Notes to Financial Highlights
(a)	In addition to the fees and expenses that the Fund bears directly, the Fund indirectly bears a pro rata share of the fees and expenses of any other funds in which it invests, if any. Such indirect expenses are not included in the Fund's reported expense ratios.
(b)	Had the Investment Manager and/or Transfer Agent not waived fees and/or reimbursed a portion of expenses, total return would have been reduced.
(c)	Ratios include line of credit interest expense which is less than 0.01%.
(d)	The benefits derived from expense reductions had an impact of less than 0.01%.
(e)	Per share amounts have been adjusted on a retroactive basis to reflect a 4 to 1 reverse stock split completed after the close of business on September 11, 2020.
(f)	Calculation of the net gain (loss) per share (both realized and unrealized) does not correlate to the aggregate realized and unrealized gain (loss) presented in the Statements of Operations due to the timing of subscriptions and redemptions of Fund shares in relation to fluctuations in the market value of the portfolio.

64 Prospectus 2022

Columbia Acorn USA®

Financial Highlights (continued)

	Net asset value, end of period	Total return	Total gross expense ratio to average net assets(a)	Total net expense ratio to average net assets(a)	Net investment income (loss) ratio to average net assets	Portfolio turnover	Net assets, end of period (000's)
Class A
Year Ended 12/31/2021	$10.14	8.74% (b)	1.40% (c)	1.39% (c), (d)	(1.03%)	69%	$53,016
Year Ended 12/31/2020	$13.58	23.70% (b)	1.44%	1.40% (d)	(0.91%)	94%	$59,050
Year Ended 12/31/2019	$11.69	30.88% (b)	1.45% (c)	1.41% (c), (d)	(0.43%)	91%	$56,578
Year Ended 12/31/2018	$10.28	(2.15%) (b)	1.44% (c)	1.42% (c), (d)	(0.49%)	86%	$49,179
Year Ended 12/31/2017	$12.48	19.14% (b)	1.44%	1.43% (d)	(0.55%)	84%	$47,960
Advisor Class
Year Ended 12/31/2021	$16.37	8.92% (b)	1.15% (c)	1.14% (c), (d)	(0.78%)	69%	$24,058
Year Ended 12/31/2020	$19.32	24.08% (b)	1.19%	1.15% (d)	(0.66%)	94%	$23,158
Year Ended 12/31/2019	$16.31	31.27% (b)	1.20% (c)	1.16% (c), (d)	(0.18%)	91%	$19,202
Year Ended 12/31/2018	$13.77	(1.91%) (b)	1.18% (c)	1.17% (c), (d)	(0.27%)	86%	$14,579
Year Ended 12/31/2017	$16.08	19.42% (b)	1.21%	1.20% (d)	(0.31%)	84%	$16,355
Class C(e)
Year Ended 12/31/2021	$15.03	7.85% (b)	2.15% (c)	2.14% (c), (d)	(1.78%)	69%	$1,809
Year Ended 12/31/2020	$18.14	22.79% (b)	2.19%	2.15% (d)	(1.66%)	94%	$2,658
Year Ended 12/31/2019	$16.47	29.93% (b)	2.20% (c)	2.16% (c), (d)	(1.19%)	91%	$3,195
Year Ended 12/31/2018	$18.07	(2.92%) (b)	2.19% (c)	2.17% (c), (d)	(1.30%)	86%	$4,608
Year Ended 12/31/2017	$26.22	18.30% (b)	2.19%	2.19% (d)	(1.31%)	84%	$9,802
Institutional Class
Year Ended 12/31/2021	$14.83	8.95% (b)	1.15% (c)	1.14% (c), (d)	(0.78%)	69%	$169,844
Year Ended 12/31/2020	$17.90	24.04% (b)	1.19%	1.15% (d)	(0.67%)	94%	$170,650
Year Ended 12/31/2019	$15.17	31.28% (b)	1.20% (c)	1.16% (c), (d)	(0.18%)	91%	$158,696
Year Ended 12/31/2018	$12.90	(1.98%) (b)	1.18% (c)	1.17% (c), (d)	(0.26%)	86%	$149,048
Year Ended 12/31/2017	$15.21	19.44% (b)	1.16%	1.16% (d)	(0.27%)	84%	$189,408
Institutional 2 Class
Year Ended 12/31/2021	$16.57	8.99% (b)	1.11% (c)	1.08% (c)	(0.71%)	69%	$3,271
Year Ended 12/31/2020	$19.50	24.10% (b)	1.14%	1.08%	(0.60%)	94%	$3,344
Year Ended 12/31/2019	$16.46	31.41% (b)	1.13% (c)	1.08% (c)	(0.09%)	91%	$3,806
Year Ended 12/31/2018	$13.87	(1.89%) (b)	1.11% (c)	1.09% (c)	(0.19%)	86%	$3,332
Year Ended 12/31/2017	$16.21	19.56% (b)	1.08%	1.08%	(0.17%)	84%	$10,133
Institutional 3 Class
Year Ended 12/31/2021	$16.84	9.09% (b)	1.05% (c)	1.04% (c)	(0.69%)	69%	$50,303
Year Ended 12/31/2020	$19.74	24.16% (b)	1.09%	1.04%	(0.55%)	94%	$77,304
Year Ended 12/31/2019	$16.65	31.45% (b)	1.08% (c)	1.03% (c)	(0.05%)	91%	$67,921
Year Ended 12/31/2018	$14.01	(1.86%) (b)	1.06% (c)	1.04% (c)	(0.11%)	86%	$55,248
Year Ended 12/31/2017	$16.36	19.60% (b)	1.05%	1.05%	(0.17%)	84%	$49,019

Prospectus 2022 65

Columbia Acorn USA®

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges

As noted in the Choosing a Share Class section of the prospectus, the sales charge reductions and waivers available to investors who purchase and hold their Fund shares through different financial intermediaries may vary. This Appendix A describes financial intermediary-specific reductions and/or waiver policies applicable to Fund shares purchased and held through the particular financial intermediary. A reduction and/or waiver that is specific to a particular financial intermediary is not available to Direct-at-Fund Accounts and does not apply in any case to non-omnibus positions wherever held. These reductions and/or waivers may apply to purchases, sales, and exchanges of Fund shares. A shareholder transacting in Fund shares through a financial intermediary identified below should carefully read the terms and conditions of the reductions and/or waivers. Please consult your financial intermediary with respect to any sales charge reduction/waiver described below.

The financial intermediary-specific information below may be provided by, or compiled from or based on information provided by, the financial intermediaries noted. While the Funds, the Investment Manager and the Distributor do not establish these financial intermediary-specific policies, our representatives are available to answer questions about these financial intermediary-specific policies and can direct you to the financial intermediary if you need help understanding them.

 Ameriprise Financial Services, LLC (Ameriprise Financial Services)

The following information has been provided by Ameriprise Financial Services:

Class A Shares Front-End Sales Charge Waivers Available at Ameriprise Financial Services:

The following information applies to Class A shares purchases if you have an account with or otherwise purchase Fund shares through Ameriprise Financial Services:

Shareholders purchasing Fund shares through an Ameriprise Financial Services brokerage account are eligible for the following front-end sales charge waivers, which may differ from those disclosed elsewhere in this prospectus or the Fund’s SAI:

■ Employer-sponsored retirement plans (e.g., 401(k) plans, 457 plans, employer-sponsored 403(b) plans, profit sharing and money purchase pension plans and defined benefit plans). For purposes of this provision, employer-sponsored retirement plans do not include SEP IRAs, Simple IRAs or SAR-SEPs.

■ Shares purchased through reinvestment of capital gains distributions and dividend reinvestment when purchasing shares of the same fund (but not any other fund within the Columbia Fund family).

■ Shares exchanged from Class C shares of the same fund in the month of or following the 7-year anniversary of the purchase date. To the extent that the Fund’s Class C Shares – Conversion to Class A Shares policy (stated outside this Appendix A) provides for a waiver with respect to exchanges of Class C shares or the conversion of Class C shares following a shorter holding period, that waiver will apply.

■ Employees and registered representatives of Ameriprise Financial Services or its affiliates and their immediate family members.

■ Shares purchased by or through qualified accounts (including IRAs, Coverdell Education Savings Accounts, 401(k)s, 403(b) TSCAs subject to ERISA and defined benefit plans) that are held by a covered family member, defined as an Ameriprise financial advisor and/or the advisor’s spouse, advisor’s lineal ascendant (mother, father, grandmother, grandfather, great grandmother, great grandfather), advisor’s lineal descendant (son, step-son, daughter, step-daughter, grandson, granddaughter, great grandson, great granddaughter) or any spouse of a covered family member who is a lineal descendant.

■ Shares purchased from the proceeds of redemptions from another fund in the Columbia Fund family, provided (1) the repurchase occurs within 90 days following the redemption, (2) the redemption and purchase occur in the same account, and (3) redeemed shares were subject to a front-end or deferred sales load (i.e. Rights of Reinstatement).

A-1 Prospectus 2022

Columbia Acorn USA®

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

 Robert W. Baird & Co. Incorporated (Baird)

The following information has been provided by Baird:

Effective June 30, 2020, shareholders purchasing Columbia Fund shares through a Baird platform or account that maintains an omnibus position with the Fund will only be eligible for the following sales charge waivers (front-end sales charge waivers and CDSC waivers) and discounts, which may differ from those disclosed elsewhere in this prospectus or the Fund’s SAI. A reduction and/or waiver that is specific to Baird will not apply to non-omnibus positions.

Front-End Sales Charge Waivers on Class A Shares Available at Baird:

■ Shares purchased through reinvestment of capital gains distributions and dividend reinvestment when purchasing shares of the same Columbia Fund.

■ Share purchases by employees and registered representatives of Baird or its affiliates and their family members as designated by Baird.

■ Shares purchased with the proceeds of redemptions from another Columbia Fund, provided (1) the repurchase occurs within 90 days following the redemption, (2) the redemption and purchase occur in the same accounts, and (3) redeemed shares were subject to a front-end or deferred sales charge (known as rights of reinstatement).

■ A shareholder in the Fund’s Class C shares will have their shares converted at net asset value to Class A shares of the same Columbia Fund if the shares are no longer subject to CDSC and the conversion is in line with the policies and procedures of Baird.

■ Employer-sponsored retirement plans or charitable accounts in a transactional brokerage account at Baird, including 401(k) plans, 457 plans, employer-sponsored 403(b) plans, profit sharing and money purchase pension plans and defined benefit plans. For purposes of this provision, employer-sponsored retirement plans do not include SEP IRAs, Simple IRAs or SAR-SEPs.

CDSC Waivers on Class A and Class C Shares Available at Baird:

■ Shares sold due to death or disability of the shareholder.

■ Shares sold as part of a systematic withdrawal plan as described in this prospectus.

■ Shares purchased due to returns of excess contributions from an IRA account.

■ Shares sold as part of a required minimum distribution for IRA and retirement accounts due to the shareholder reaching the qualified age based on applicable IRS regulations.

■ Shares sold to pay Baird fees but only if the transaction is initiated by Baird.

■ Shares acquired through a right of reinstatement.

Front-End Sales Charge Discounts Available at Baird: Breakpoints and/or Rights of Accumulations:

■ Breakpoints as described in this prospectus.

■ Rights of accumulations which entitle shareholders to breakpoint discounts will be automatically calculated based on the aggregated holding of Columbia Fund assets held by accounts within the purchaser’s household at Baird. Eligible Columbia Fund assets not held at Baird may be included in the rights of accumulations calculation only if the shareholder notifies his or her financial advisor about such assets.

■ Letters of Intent (LOI) allow for breakpoint discounts based on anticipated purchases of Columbia Funds through Baird, over a 13-month period of time.

Prospectus 2022 A-2

Columbia Acorn USA®

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

 Edward D. Jones & Co., L.P. (Edward Jones)

Policies Regarding Transactions Through Edward Jones

The following information has been provided by Edward Jones:

Effective on or after January 15, 2021, the following information supersedes prior information with respect to transactions and positions held in Columbia Fund shares through an Edward Jones system. Clients of Edward Jones (also referred to as "shareholders") purchasing Columbia Fund shares on the Edward Jones commission and fee-based platforms are eligible only for the following sales charge discounts (also referred to as "breakpoints") and waivers, which can differ from discounts and waivers described elsewhere in this prospectus or the Fund’s SAI or through another broker-dealer. In all instances, it is the shareholder's responsibility to inform Edward Jones at the time of purchase of any relationship, holdings of Columbia Funds and Future Scholars Program, or other facts qualifying the purchaser for discounts or waivers. Edward Jones can ask for documentation of such circumstance. Shareholders should contact Edward Jones if they have questions regarding their eligibility for these discounts and waivers.

Breakpoints

■ Breakpoint pricing, otherwise known as volume pricing, at dollar thresholds as described in this prospectus.

Rights of Accumulation (ROA)

■ The applicable sales charge on a purchase of Class A shares is determined by taking into account all share classes (except certain money market funds and any assets held in group retirement plans) of Columbia Funds and Future Scholars Program held by the shareholder or in an account grouped by Edward Jones with other accounts for the purpose of providing certain pricing considerations ("pricing groups"). If grouping assets as a shareholder, this includes all share classes held on the Edward Jones platform and/or held on another platform. The inclusion of eligible Columbia Fund assets in the ROA calculation is dependent on the shareholder notifying Edward Jones of such assets at the time of calculation. Money market funds are included only if such shares were sold with a sales charge at the time of purchase or acquired in exchange for shares purchased with a sales charge.

■ The employer maintaining a SEP IRA plan and/or SIMPLE IRA plan may elect to establish or change ROA for the IRA accounts associated with the plan to a plan-level grouping as opposed to including all share classes at a shareholder or pricing group level.

■ ROA is determined by calculating the higher of cost minus redemptions or market value (current shares x NAV).

Letter of Intent (LOI)

■ Through a LOI, shareholders can receive the sales charge and breakpoint discounts for purchases shareholders intend to make over a 13-month period from the date Edward Jones receives the LOI. The LOI is determined by calculating the higher of cost or market value of qualifying holdings at LOI initiation in combination with the value that the shareholder intends to buy over a 13-month period to calculate the front-end sales charge and any breakpoint discounts. Each purchase the shareholder makes during that 13-month period will receive the sales charge and breakpoint discount that applies to the total amount. The inclusion of eligible Columbia Fund assets in the LOI calculation is dependent on the shareholder notifying Edward Jones of such assets at the time of calculation. Purchases made before the LOI is received by Edward Jones are not adjusted under the LOI and will not reduce the sales charge previously paid. Sales charges will be adjusted if LOI is not met.

■ If the employer maintaining a SEP IRA plan and/or SIMPLE IRA plan has elected to establish or change ROA for the IRA accounts associated with the plan to a plan-level grouping, LOIs will also be at the plan-level and may only be established by the employer.

A-3 Prospectus 2022

Columbia Acorn USA®

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

Sales Charge Waivers

Sales charges are waived for the following shareholders and in the following situations:

■ Associates of Edward Jones and its affiliates and their family members who are in the same pricing group (as determined by Edward Jones under its policies and procedures) as the associate. This waiver will continue for the remainder of the associate's life if the associate retires from Edward Jones in good-standing and remains in good standing pursuant to Edward Jones' policies and procedures.

■ Shares purchased in an Edward Jones fee-based program.

■ Shares purchased through reinvestment of capital gains distributions and dividend reinvestment.

■ Shares purchased from the proceeds of redeemed shares of Columbia Funds so long as the following conditions are met: 1) the proceeds are from the sale of shares within 60 days of the purchase, and 2) the sale and purchase are made in the same share class and the same account or the purchase is made in an individual retirement account with proceeds from liquidations in a non-retirement account.

■ Shares exchanged into Class A shares from another share class so long as the exchange is into the same fund and was initiated at the discretion of Edward Jones. Edward Jones is responsible for any remaining CDSC due to the fund company, if applicable. Any future purchases are subject to the applicable sales charge as disclosed in this prospectus.

■ Exchanges from Class C shares to Class A shares of the same fund, generally, in the 84th month following the anniversary of the purchase date or earlier at the discretion of Edward Jones.

Contingent Deferred Sales Charge (CDSC) Waivers

If the shareholder purchases shares that are subject to a CDSC and those shares are redeemed before the CDSC is expired, the shareholder is responsible to pay the CDSC except in the following conditions:

■ The death or disability of the shareholder.

■ Systematic withdrawals with up to 10% per year of the account value.

■ Return of excess contributions from an Individual Retirement Account (IRA).

■ Shares sold as part of a required minimum distribution for IRA and retirement accounts if the redemption is taken in or after the year the shareholder reaches qualified age based on applicable IRS regulations.

■ Shares sold to pay Edward Jones fees or costs in such cases where the transaction is initiated by Edward Jones.

■ Shares exchanged in an Edward Jones fee-based program.

■ Shares acquired through NAV reinstatement.

■ Shares redeemed at the discretion of Edward Jones for Minimum Balances, as described below.

Other Important Information Regarding Transactions Through Edward Jones

Minimum Purchase Amounts

■ Initial purchase minimum: $250

■ Subsequent purchase minimum: none

Minimum Balances

■ Edward Jones has the right to redeem at its discretion Fund holdings with a balance of $250 or less. The following are examples of accounts that are not included in this policy:

■ A fee-based account held on an Edward Jones platform.

■ A 529 account held on an Edward Jones platform.

■ An account with an active systematic investment plan or LOI.

Prospectus 2022 A-4

Columbia Acorn USA®

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

Exchanging Share Classes

■ At any time it deems necessary, Edward Jones has the authority to exchange at NAV a shareholder's holdings in the Fund to Class A shares.

 Janney Montgomery Scott LLC (Janney)

The following information has been provided by Janney:

Effective May 1, 2020, if you purchase Columbia Fund shares through a Janney brokerage account, you will be eligible for the following load waivers (front-end sales charge waivers and CDSC, or back-end sales charge, waivers) and discounts, which may differ from those disclosed elsewhere in this prospectus or the Fund’s SAI. A reduction and/or waiver that is specific to Janney does not apply to non-omnibus positions.

Front-End Sales Charge* Waivers on Class A Shares Available at Janney

■ Shares purchased through reinvestment of capital gains distributions and dividend reinvestment when purchasing shares of the same fund (but not any other Columbia Fund).

■ Shares purchased by employees and registered representatives of Janney or its affiliates and their family members as designated by Janney.

■ Shares purchased from the proceeds of redemptions from another Columbia Fund, provided (1) the repurchase occurs within ninety (90) days following the redemption, (2) the redemption and purchase occur in the same account, and (3) redeemed shares were subject to a front-end or deferred sales load (i.e., right of reinstatement).

■ Employer-sponsored retirement plans (e.g., 401(k) plans, 457 plans, employer-sponsored 403(b) plans, profit sharing and money purchase pension plans and defined benefit plans). For purposes of this provision, employer-sponsored retirement plans do not include SEP IRAs, Simple IRAs, SAR-SEPs or Keogh plans.

■ Shares acquired through a right of reinstatement.

■ Class C shares that are no longer subject to a CDSC and are converted to Class A shares of the same fund pursuant to Janney’s policies and procedures.

CDSC Waivers on Class A and C Shares Available at Janney

■ Shares sold upon the death or disability of the shareholder.

■ Shares sold as part of a systematic withdrawal plan as described in this prospectus.

■ Shares purchased in connection with a return of excess contributions from an IRA account.

■ Shares sold as part of a required minimum distribution for IRA and retirement accounts if the redemption is taken in or after the year the shareholder reaches qualified age based on applicable IRS regulations.

■ Shares sold to pay Janney fees but only if the transaction is initiated by Janney.

■ Shares acquired through a right of reinstatement.

■ Shares exchanged into the same share class of a different fund.

Front-End Sales Charge* Discounts Available at Janney: Breakpoints, Rights of Accumulation, and/or Letters of Intent

■ Breakpoints as described in this prospectus.

■ Rights of accumulation (“ROA”), which entitle shareholders to breakpoint discounts, will be automatically calculated based on the aggregated holding of Columbia Fund assets held by accounts within the purchaser’s household at Janney. Eligible Columbia Fund assets not held at Janney may be included in the ROA calculation only if the shareholder notifies his or her financial advisor about such assets.

■ Letters of intent which allow for breakpoint discounts based on anticipated purchases within the Columbia Funds, over a 13-month time period. Eligible Columbia Fund assets not held at Janney may be included in the calculation of letters of intent only if the shareholder notifies his or her financial advisor about such assets.

A-5 Prospectus 2022

Columbia Acorn USA®

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

* Also referred to as an “initial sales charge”.

 Merrill Lynch Pierce, Fenner & Smith Incorporated (Merrill Lynch)

The following information has been provided by Merrill Lynch:

Shareholders purchasing Columbia Fund shares through a Merrill Lynch platform or account will be eligible only for the following load waivers (front-end sales charge waivers and contingent deferred, or back-end, sales charge waivers) and discounts, which may differ from those disclosed elsewhere in this prospectus or the Fund’s SAI:

Front-End Load Discounts Available at Merrill Lynch:

Merrill Lynch makes available breakpoint discounts on shares of the Fund through:

■ Breakpoints as described in this prospectus.

■ Rights of Accumulation (ROA) which entitle shareholders to breakpoint discounts as described in this prospectus will be automatically calculated based on the aggregated holding of Columbia Fund assets held by accounts (including 529 program holdings, where applicable) within the purchaser’s household at Merrill Lynch. Eligible Columbia Fund assets not held at Merrill Lynch may be included in the ROA calculation only if the shareholder notifies his or her financial advisor about such assets.

■ Letters of Intent (LOI) which allow for breakpoint discounts based on anticipated purchases of Columbia Funds, through Merrill Lynch, over a 13-month period of time (if applicable).

Front-End Sales Load Waivers on Class A Shares Available at Merrill Lynch:

■ Employer-sponsored retirement, deferred compensation and employee benefit plans (including health savings accounts) and trusts used to fund those plans, provided that the shares are not held in a commission-based brokerage account and shares are held for the benefit of the plan.

■ Shares purchased by a 529 Plan (does not include 529 Plan units or 529-specific share classes or equivalents).

■ Shares purchased through a Merrill Lynch affiliated investment advisory program.

■ Shares exchanged due to the holdings moving from a Merrill Lynch affiliated investment advisory program to a Merrill Lynch brokerage (non-advisory) account pursuant to Merrill Lynch’s policies relating to sales load discounts and waivers.

■ Shares purchased by third party investment advisors on behalf of their advisory clients through Merrill Lynch’s platform.

■ Shares of funds purchased through the Merrill Edge Self-Directed platform (if applicable).

■ Shares purchased through reinvestment of capital gains distributions and dividend reinvestment when purchasing shares of the same fund (but not any other Columbia Fund).

■ Shares exchanged from Class C (i.e., level-load) shares of the same fund pursuant to Merrill Lynch’s policies relating to sales load discounts and waivers.

■ Employees and registered representatives of Merrill Lynch or its affiliates and their family members.

■ Directors or Trustees of the Fund, and employees of the Fund’s investment adviser or any of its affiliates, as described in this prospectus.

■ Eligible shares purchased from the proceeds of redemptions from another Columbia Fund, provided (1) the repurchase occurs within 90 days following the redemption, (2) the redemption and purchase occur in the same account, and (3) redeemed shares were subject to a front-end or deferred sales load (known as Rights of Reinstatement). Automated transactions (i.e. systematic purchases and withdrawals) and purchases made after shares are automatically sold to pay Merrill Lynch’s account maintenance fees are not eligible for reinstatement.

CDSC Waivers on Class A and C Shares Available at Merrill Lynch:

■ Death or disability of the shareholder.

Prospectus 2022 A-6

Columbia Acorn USA®

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

■ Shares sold as part of a systematic withdrawal plan as described in this prospectus.

■ Return of excess contributions from an IRA Account.

■ Shares sold as part of a required minimum distribution for IRA and retirement accounts pursuant to the Internal Revenue Code.

■ Shares sold to pay Merrill Lynch fees but only if the transaction is initiated by Merrill Lynch.

■ Shares acquired through a right of reinstatement.

■ Shares held in retirement brokerage accounts, that are exchanged for a lower cost share class due to transfer to certain fee based accounts or platforms (applicable to Class A and Class C shares only).

■ Shares received through an exchange due to the holdings moving from a Merrill Lynch affiliated investment advisory program to a Merrill Lynch brokerage (non-advisory) account pursuant to Merrill Lynch’s policies relating to sales load discounts and waivers.

 Morgan Stanley Smith Barney, LLC (Morgan Stanley Wealth Management)

The following information has been provided by Morgan Stanley Wealth Management:

Effective July 1, 2018, shareholders purchasing Columbia Fund shares through a Morgan Stanley Wealth Management transactional brokerage account will be eligible only for the following front-end sales charge waivers with respect to Class A shares, which may differ from and may be more limited than those disclosed elsewhere in this prospectus or the Fund’s SAI.

Front-End Sales Charge Waivers on Class A Shares Available at Morgan Stanley Wealth Management Effective July 1, 2018:

■ Employer-sponsored retirement plans (e.g., 401(k) plans, 457 plans, employer-sponsored 403(b) plans, profit sharing and money purchase pension plans and defined benefit plans).  For purposes of this provision, employer-sponsored retirement plans do not include SEP IRAs, Simple IRAs, SAR-SEPs or Keogh plans.

■ Morgan Stanley employee and employee-related accounts according to Morgan Stanley’s account linking rules.

■ Shares purchased through reinvestment of dividends and capital gains distributions when purchasing shares of the same fund.

■ Shares purchased through a Morgan Stanley self-directed brokerage account.

■ Class C (i.e., level-load) shares that are no longer subject to a CDSC and are exchanged for Class A shares of the same fund pursuant to Morgan Stanley Wealth Management’s share class exchange program.

■ Shares purchased from the proceeds of redemptions from another Columbia Fund, provided (i) the repurchase occurs within 90 days following the redemption, (ii) the redemption and purchase occur in the same account, and (iii) redeemed shares were subject to a front-end or deferred sales charge.

 Raymond James & Associates, Inc., Raymond James Financial Services, Inc. and each entity’s affiliates (Raymond James)

The following information has been provided by Raymond James:

Intermediary-Defined Sales Charge Waiver Policies:

The availability of certain initial or deferred sales charge waivers and discounts may depend on the particular financial intermediary or type of account through which you purchase or hold Columbia Fund shares.

Intermediaries may have different policies and procedures regarding the availability of front-end sales load waivers or contingent deferred (back-end) sales load (CDSC) waivers, which are discussed below. In all instances, it is the purchaser’s responsibility to notify the Fund or the purchaser’s financial intermediary at the time of purchase of any

A-7 Prospectus 2022

Columbia Acorn USA®

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

relationship or other facts qualifying the purchaser for sales charge waivers or discounts. For waivers and discounts not available through a particular intermediary, shareholders will have to purchase Columbia Fund shares directly from the Fund or through another intermediary to receive these waivers or discounts.

Raymond James:

Effective March 1, 2019, shareholders purchasing Columbia Fund shares through a Raymond James platform or account, or through an introducing broker-dealer or independent registered investment adviser for which Raymond James provides trade execution, clearance, and/or custody services, will be eligible only for the following load waivers (front-end sales charge waivers and contingent deferred, or back-end, sales charge waivers) and discounts, which may differ from those disclosed elsewhere in this prospectus or the Fund’s SAI.

Front-End Sales Load Waivers on Class A Shares Available at Raymond James:

■ Shares purchased in an investment advisory program.

■ Shares purchased within the Columbia Funds through a systematic reinvestment of capital gains and dividend distributions.

■ Employees and registered representatives of Raymond James or its affiliates and their family members as designated by Raymond James.

■ Shares purchased from the proceeds of redemptions within the Columbia Funds, provided (1) the repurchase occurs within 90 days following the redemption, (2) the redemption and purchase occur in the same account, and (3) redeemed shares were subject to a front-end or deferred sales load (known as Rights of Reinstatement).

■ A shareholder in the Fund’s Class C shares will have their shares converted at net asset value to Class A shares (or the appropriate share class) of the Fund if the shares are no longer subject to a CDSC and the conversion is in line with the policies and procedures of Raymond James.

CDSC Waivers on Class A and Class C Shares Available at Raymond James:

■ Death or disability of the shareholder.

■ Shares sold as part of a systematic withdrawal plan as described in this prospectus.

■ Return of excess contributions from an IRA Account.

■ Shares sold as part of a required minimum distribution for IRA and retirement accounts due to the shareholder reaching the qualified age based on applicable IRS regulations as described in this prospectus.

■ Shares sold to pay Raymond James fees but only if the transaction is initiated by Raymond James.

■ Shares acquired through a right of reinstatement.

Front-End Load Discounts Available at Raymond James: Breakpoints, Rights of Accumulation and/or Letters of Intent:

■ Breakpoints as described in this prospectus.

■ Rights of accumulation which entitle shareholders to breakpoint discounts will be automatically calculated based on the aggregated holding of Columbia Fund assets held by accounts within the purchaser’s household at Raymond James. Eligible Columbia Fund assets not held at Raymond James may be included in the calculation of rights of accumulation only if the shareholder notifies his or her financial advisor about such assets.

■ Letters of intent which allow for breakpoint discounts based on anticipated purchases within the Columbia Funds, over a 13-month time period. Eligible Columbia Fund assets not held at Raymond James may be included in the calculation of letters of intent only if the shareholder notifies his or her financial advisor about such assets.

 Stifel Financial Corp. (Stifel)

The following information has been provided by Stifel:

Prospectus 2022 A-8

Columbia Acorn USA®

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

Effective June 30, 2020, Class C shares of Columbia Funds that were purchased through a Stifel platform or account that maintains an omnibus position with the Fund that are no longer subject to a CDSC are exchanged to Class A shares of the same Columbia Fund pursuant to Stifel’s policies and procedures. This does not apply to non-omnibus positions.

 U.S. Bancorp Investments, Inc. (USBI)

The following information has been provided by USBI:

Effective September of 2021, shareholders purchasing Columbia Fund shares through a USBI platform or who own shares for which USBI is the broker-dealer, where the shares are held in an omnibus account, will only be eligible for the following front-end sales charge waivers and discounts, which may differ from those disclosed elsewhere in this prospectus or the Fund’s SAI.

All other sales charge waivers and reduction described elsewhere in this prospectus or the Fund’s SAI still apply.

USBI Conversion of Class C shares

Class C (i.e., level-load) shares that are no longer subject to a contingent deferred sales charge are systematically converted to the Class A shares of the same fund pursuant to USBI’s share class exchange policy.

 Additional Sales Charge Reductions and/or Waivers Available at Certain Financial Intermediaries

Shareholders purchasing Columbia Fund shares through a platform or account of RBC Capital Markets, LLC are eligible for the following sales charge waiver:

Class A Shares Front-End Sales Charge Waiver Available at RBC Capital Markets, LLC:

■ For employer-sponsored retirement plans held through a commissionable brokerage account, Class A shares are available at NAV (i.e., without a sales charge). For this purpose, employer-sponsored retirement plans include, but are not limited to, 401(k) plans, 457 plans, employer-sponsored 403(b) plans, profit sharing and money purchase pension plans and defined benefit plans. For purposes of this provision, employer-sponsored retirement plans do not include SEP IRAs, Simple IRAs, SAR-SEPs or Keogh plans.

A-9 Prospectus 2022

[This page intentionally left blank]

Columbia Acorn USA^®

P.O. Box 219104
Kansas City, MO 64121-9104

Columbia Acorn Family of Funds

Additional Information About the Fund

Additional information about the Fund’s investments is available in the Fund’s annual and semiannual reports to shareholders. In the annual report, you will find a discussion of the market conditions and investment strategies that significantly affected the Fund’s performance during its last fiscal year. The SAI also provides additional information about the Fund and its policies. The SAI, which has been filed with the SEC, is legally part of this prospectus (incorporated by reference). To obtain these documents free of charge, to request other information about the Fund and to make shareholder inquiries, please contact the Fund as follows:

By Mail:  Columbia Management Investment Services Corp.
P.O. Box 219104
Kansas City, MO 64121-9104

By Telephone: 800.345.6611

Online: columbiathreadneedleus.com

Shareholder Communications with the Board

The Fund’s Board of Trustees has adopted procedures by which shareholders may communicate with the Board. Shareholders who wish to communicate with the Board should send their written communications to the Board by mail, c/o Columbia Wanger Asset Management, LLC, 71 S. Wacker Drive, Suite 2500, Chicago, IL 60606, Attention: Secretary. Shareholder communications must (i) be in writing, (ii) identify the Columbia Acorn Fund to which the communication relates and (iii) state the particular class of shares and number of shares held by the communicating shareholder.

Obtaining Additional Information from the SEC

Reports and other information about the Fund are also available in the EDGAR Database on the SEC’s website at http://www.sec.gov. You can receive copies of this information, for a duplication fee, by electronic request at the following e-mail address: publicinfo@sec.gov.

The investment company registration number of Columbia Acorn Trust, of which the Fund is a series, is 811-01829.

Columbia Threadneedle Investments is the global brand name of the Columbia and Threadneedle group of companies.
The Fund is distributed by Columbia Management Investment Distributors, Inc., 290 Congress Street, Boston, MA 02210.

© 2022 Columbia Management Investment Advisers, LLC. All rights reserved.

PRO115_12_M01_(05/22)

 

Prospectus

May 1, 2022

Columbia Acorn Family of Funds

Managed by Columbia Wanger Asset Management, LLC

Columbia 
  Thermostat Fund^SM

Class	Ticker Symbol
A	CTFAX
Advisor (Class Adv)	CTORX
C	CTFDX

Class	Ticker Symbol
Institutional (Class Inst)	COTZX
Institutional 2 (Class Inst2)	CQTRX
Institutional 3 (Class Inst3)	CYYYX

As with all mutual funds, the Securities and Exchange Commission (SEC) has not approved or disapproved these securities or passed upon the adequacy of this prospectus. Any representation to the contrary is a criminal offense.

Table of Contents

Summary of the Fund	3
Investment Objective	3
Fees and Expenses of the Fund	3
Principal Investment Strategies	4
Principal Risks	9
Performance Information	26
Fund Management	28
Purchase and Sale of Fund Shares	29
Tax Information	29
Payments to Broker-Dealers and Other Financial Intermediaries	29
Portfolio Funds Summary	30
More Information About the Fund	39
Investment Objective	39
Additional Investment Strategies and Policies	39
Board of Trustees	44
Primary Service Provider Contracts	44
Other Roles and Relationships of Ameriprise Financial and its Affiliates — Certain Conflicts of Interest	47
Certain Legal Matters	48
Choosing a Share Class	49
The Funds	49
Summary of Share Class Features	49
Sales Charges and Commissions	55
Reductions/Waivers of Sales Charges	58
Distribution and Service Fees	62
Financial Intermediary Compensation	63
Buying, Selling and Exchanging Shares	65
Share Price Determination	65
Transaction Rules and Policies	66
Opening an Account and Placing Orders	70
Buying Shares	72
Selling Shares	77
Exchanging Shares	79
Distributions and Taxes	82
Distributions to Shareholders	82
Taxes	83
Financial Highlights	85
Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges	A-1

2

Columbia Thermostat Fund^SM

Summary of the Fund

Investment Objective

Columbia Thermostat Fund^SM (the Fund) seeks long-term capital appreciation.

Fees and Expenses of the Fund

This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below. You may qualify for sales charge discounts if you and members of your immediate family invest, or agree to invest in the future, at least $50,000 in certain classes of shares of eligible funds distributed by Columbia Management Investment Distributors, Inc. (the Distributor). More information is available about these and other sales charge discounts and waivers from your financial intermediary, and can be found in the Choosing a Share Class section beginning on page 49 of the Fund’s prospectus, in Appendix A to the prospectus beginning on page A-1 and in Appendix S to the Statement of Additional Information (SAI) under Sales Charge Waivers beginning on page S-1.

Shareholder Fees (fees paid directly from your investment)
	Class A	Class C	Classes Adv, Inst, Inst2 and Inst3
Maximum sales charge (load) imposed on purchases (as a % of offering price)	5.75%	None	None
Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)	1.00%(a)	1.00%(b)	None

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
	Class A	Class Adv	Class C	Class Inst	Class Inst2	Class Inst3
Management fees	0.10%	0.10%	0.10%	0.10%	0.10%	0.10%
Distribution and/or service (12b-1) fees	0.25%	0.00%	1.00%	0.00%	0.00%	0.00%
Other expenses	0.19%	0.19%	0.19%	0.19%	0.14%	0.11%
Acquired fund fees and expenses	0.36%	0.36%	0.36%	0.36%	0.36%	0.36%
Total annual Fund operating expenses(c)	0.90%	0.65%	1.65%	0.65%	0.60%	0.57%
Fee waivers and/or expense reimbursements(d)	(0.04%)	(0.04%)	(0.04%)	(0.04%)	(0.04%)	(0.05%)
Total annual Fund operating expenses after fee waivers and/or expense reimbursements	0.86%	0.61%	1.61%	0.61%	0.56%	0.52%

(a)	This charge is imposed on certain investments of between $1 million and $50 million redeemed within 18 months after purchase, as follows: 1.00% if redeemed within 12 months after purchase, and 0.50% if redeemed more than 12, but less than 18, months after purchase, with certain limited exceptions.
(b)	This charge applies to redemptions within 12 months after purchase, with certain limited exceptions.
(c)	“Total annual Fund operating expenses” include acquired fund (Portfolio Fund) fees and expenses (expenses the Fund incurs indirectly through its investments in other funds) and may be higher than the ratio of expenses to average net assets shown in the Financial Highlights section of this prospectus because the ratio of expenses to average net assets does not include Portfolio Fund (acquired fund) fees and expenses.

(d) Columbia Wanger Asset Management, LLC (the Investment Manager) has contractually agreed to waive fees and reimburse certain expenses of the Fund, through April 30, 2023, so that ordinary operating expenses (excluding transaction costs and certain other investment-related expenses, interest and fees on borrowings and expenses associated with the Fund’s investment in other investment companies, including the Portfolio Funds) do not exceed the annual rates of 0.50% for Class A shares, 0.25% for Class Adv shares, 1.25% for Class C shares, 0.25% for Class Inst shares, 0.20% for Class Inst2 shares and 0.16% for Class Inst3 shares. This arrangement may only be amended or terminated with approval from the Fund's Board of Trustees and the Investment Manager.

 Example

The following example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example illustrates the hypothetical expenses that you would incur over the time periods indicated, and assumes that:

■ you invest $10,000 in the applicable class of Fund shares for the periods indicated,

Prospectus 2022 3

Columbia Thermostat Fund^SM

Summary of the Fund (continued)

■ your investment has a 5% return each year, and

■ the Fund’s total annual operating expenses remain the same as shown in the Annual Fund Operating Expenses table above.

Since the waivers and/or reimbursements shown in the Annual Fund Operating Expenses table above expire as indicated in the preceding table, they are only reflected in the 1 year example and the first year of the other examples. Although your actual costs may be higher or lower, based on the assumptions listed above, your costs would be:

	1 year	3 years	5 years	10 years
Class A (whether or not shares are redeemed)	$658	$842	$1,041	$1,616
Class Adv (whether or not shares are redeemed)	$62	$204	$358	$807
Class C (assuming redemption of all shares at the end of the period)	$264	$516	$893	$1,751
Class C (assuming no redemption of shares)	$164	$516	$893	$1,751
Class Inst (whether or not shares are redeemed)	$62	$204	$358	$807
Class Inst2 (whether or not shares are redeemed)	$57	$188	$331	$746
Class Inst3 (whether or not shares are redeemed)	$53	$178	$313	$709

Portfolio Turnover

The Fund will indirectly bear the expenses associated with portfolio turnover of the underlying Portfolio Funds in which the Fund invests. Each Portfolio Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A Portfolio Fund’s higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when its shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 49% of the average value of its portfolio.

Principal Investment Strategies

The Fund is primarily managed as a fund that invests in other funds (i.e., a “fund-of-funds”) that seeks to achieve its investment objective by investing its assets among a selected group of underlying stock and bond mutual funds and exchanged-traded funds (ETFs) for which Columbia Wanger Asset Management, LLC, the Fund’s investment adviser (the Investment Manager) or its affiliates, including Columbia Management Investment Advisers, LLC (Columbia Management), serves as investment adviser or principal underwriter (the Portfolio Funds). Under normal circumstances, the Fund allocates at least 95% of its net assets (stock/bond assets) among the Portfolio Funds according to an asset allocation table based on the current level of the Standard & Poor’s (S&P) 500^® Index.

Generally, the Fund’s allocation to stock funds increases as the S&P 500^® Index declines and decreases as the S&P 500^® Index rises. When the S&P 500^® Index goes up in relation to trading range bands that are predetermined by the Investment Manager, the Fund sells a portion of its stock Portfolio Funds and invests more in the bond Portfolio Funds, and when the S&P 500^® Index goes down in relation to the predetermined bands, the Fund increases its investment in the stock Portfolio Funds. Under normal circumstances, the Fund may invest up to 5% of net assets plus any cash received that day in cash, high quality short-term paper and government securities.

Although many asset allocation funds follow a basic approach of moving assets from stocks to bonds when the equity market goes up, and from bonds to stocks when the equity market goes down, some are run by investment managers who allocate fund assets by making subjective decisions based on complicated economic and financial models and complex graphs of market behavior. By contrast, the day-to-day investment decisions for the Fund are made according to a single predetermined allocation table set forth below. The temperature in your house is run by a single rule: your thermostat turns on the furnace if your house is too cold or turns on the air conditioner if your house is too warm. This Fund works the same way, so it is named Columbia Thermostat Fund.

4 Prospectus 2022

Columbia Thermostat Fund^SM

Summary of the Fund (continued)

Just as a thermostat may be set at different ranges for different seasons, the structure and allocation ranges of the Fund’s asset allocation table may be changed from time to time between two forms, based on the Investment Manager’s determination of whether it expects the equity market to be moving over the next year in a side-ways or non-directional pattern, which the Investment Manager terms an “expensive” market, or to be trending upward, which the Investment Manager terms a “normal” market. The Investment Manager’s process and methodology for determining whether the current market is “expensive” or “normal” and the structure of each form of allocation table are described in more detail below under Determination of Current Market State. Such determination will be made on at least an annual basis and will be reflected in the asset allocation table disclosed in this prospectus. In general, the two different forms of allocation table are intended to maximize the capture of value under the two different sets of market conditions.

The Fund’s current asset allocation table, which is set forth below, has been in place since May 1, 2021 and reflects the Investment Manager’s determination that the equity market is currently “expensive.” This structure of the Fund’s current asset allocation table reflects the same form that was in place from the Fund’s inception in 2002 through April 30, 2020. From May 1, 2020 through April 30, 2021, the asset allocation table in place for the Fund reflected the Investment Manager’s determination that the equity market was “normal.” The asset allocation table is updated at least annually to reflect the median historical information used in the table, and the resulting S&P 500^® Index levels used to create the bands around the median, regardless of the market state.

Stock/Bond Allocation Table
	How the Fund will Invest the Stock/Bond Assets
Level of the S&P 500® Index	Stock Percentage	Bond Percentage
over 4239	10%	90%
over 4076 – 4239	15%	85%
over 3919 – 4076	20%	80%
over 3768 – 3919	25%	75%
over 3623 – 3768	30%	70%
over 3484 – 3623	35%	65%
over 3350 – 3484	40%	60%
over 3221 – 3350	45%	55%
over 3095 – 3221	50%	50%
over 2971 – 3095	55%	45%
over 2852 – 2971	60%	40%
over 2738 – 2852	65%	35%
over 2628 – 2738	70%	30%
over 2523 – 2628	75%	25%
over 2422 – 2523	80%	20%
over 2325 – 2422	85%	15%
2325 and under	90%	10%

When the S&P 500^® Index moves into a new band on the table, the Fund will rebalance the stock/bond mix to reflect the new S&P 500^® Index price level by redeeming shares of some Portfolio Funds and purchasing shares of other Portfolio Funds. Any such rebalancing typically will be implemented promptly. However, there are two circumstances when a rebalancing may be implemented over a longer timeline. First, when a rebalancing or allocation table change would trigger a 10% point or greater change in stock and bond allocations or individual Portfolio Funds, the rebalancing may be implemented over a period of up to two weeks, if deemed by the Investment Manager to be in the best interest of shareholders. The second exception is a “31-day Rule;” in order to reduce taxable events and minimize short-term trading if the S&P 500^® Index price moves back and forth across a band in the allocation table,

Prospectus 2022 5

Columbia Thermostat Fund^SM

Summary of the Fund (continued)

after the Fund has increased its percentage allocation to either stock funds or bond funds, it will not decrease that allocation for at least 31 days. Following a change in the Fund’s stock/bond mix, if the S&P 500^® Index remains within the same band for a while, normal market fluctuations will change the values of the Fund’s holdings of stock Portfolio Funds and bond Portfolio Funds. The Investment Manager will invest cash flows from sales (or redemptions) of Fund shares to bring the stock/bond mix back toward the allocation percentages for that S&P 500^® Index band. For example, if the S&P 500^® Index is in the 2628 band, and the value of the holdings of the stock Portfolio Funds has dropped to 68% of the value of the holdings of all Portfolio Funds, the Investment Manager would invest new cash in the stock Portfolio Funds (or cash for redemptions would come from the bond Portfolio Funds) to restore the 70% stock allocation. If the 31-day Rule is in effect, the Investment Manager will invest new cash at the stock/bond percentage allocation as of the latest rebalancing.

As another illustrative example, suppose the following:

Date	Level of the S&P 500® Index	How the Fund will invest the Stock/ Bond Assets(1)
Nov. 1	We begin when the market is 3200	50% stocks, 50% bonds
Dec. 1	The S&P 500® goes to 3300	rebalance 45% stocks, 55% bonds
Dec. 6	The S&P 500® drops back to 3180	no reversal for 31 days
Jan. 2	The S&P 500® is at 3150	rebalance 50% stocks, 50% bonds
Jan. 20	The S&P 500 drops to 3000	rebalance 55% stocks, 45% bonds(2)
Jan. 30	The S&P 500® goes to 3125	no reversal for 31 days
Feb. 20	The S&P 500® is at 3130	rebalance 50% stocks, 50% bonds

⁽¹⁾ For each rebalancing the Fund will trade the underlying stock and bond Portfolio Funds on the next business day.

⁽²⁾ The market has made a continuation move by going through a second action level, not a reversal move, so the 31-day Rule does not apply in this case.

The Investment Manager chooses the Portfolio Funds to be generally consistent with the composition of the Fund’s primary stock and bond benchmarks and to allow the Fund to participate in strategies the Investment Manager believes can provide additional return due to active management.

The following table shows the stock and bond Portfolio Funds that the Fund currently uses in its “fund-of-funds” structure and the current target percentage for each Portfolio Fund within the stock or bond asset class. As described more fully below, the Investment Manager may substitute or add additional Portfolio Funds at any time, including funds introduced after the date of this prospectus. The target percentage within each asset class category is achieved by rebalancing the investments within the asset class whenever the S&P 500^® Index moves into a new band on the allocation table, subject to the 31-day Rule described above. The Fund will not liquidate its investment in one Portfolio Fund in order to invest in another Portfolio Fund except in connection with a rebalancing due to a move of the S&P 500^® Index into a new band (or due to a change by the Investment Manager in the Portfolio Funds or to the relative target percentages among them). Until a subsequent rebalancing, the Fund’s cash flows are invested in, or redeemed from, the Portfolio Funds in a manner that will reduce any deviation of the relative values of the Fund’s holdings of the Portfolio Funds from the percentages shown below.

Allocation of Stock/Bond Assets Within Asset Classes
Stock Funds	Type of Fund	Allocation
Columbia Acorn® Fund	Small/Mid-cap growth	10%
Columbia Contrarian Core Fund	Large-cap blend	15%
Columbia Emerging Markets Fund	International core	10%
Columbia Large Cap Enhanced Core Fund	Large-cap blend	15%
Columbia Large Cap Index Fund	Large-cap blend	30%
Columbia Research Enhanced Core ETF	Beta Advantage® U.S. equity	10%
Columbia Select Mid Cap Value Fund	Mid-cap value	10%

6 Prospectus 2022

Columbia Thermostat Fund^SM

Summary of the Fund (continued)

Allocation of Stock/Bond Assets Within Asset Classes
Total		100%
Bond Funds	Type of Fund	Allocation
Columbia Corporate Income Fund	Corporate bond	10%
Columbia Diversified Fixed Income Allocation ETF	Beta Advantage® multi-sector bond	10%
Columbia Quality Income Fund	Government bond	20%
Columbia Short Term Bond Fund	Short term bond	15%
Columbia Total Return Bond Fund	Intermediate core bond	10%
Columbia U.S. Treasury Index Fund	U.S. Treasury notes/bonds	35%
Total		100%

See the Portfolio Funds Summary section of this prospectus for information about the Portfolio Funds’ investment objectives and principal investment strategies. Each of the Portfolio Funds is managed by the Investment Manager or its affiliates. The Fund does not pay any sales load on its purchases of shares of the Portfolio Funds.

The Investment Manager has the authority to review the Portfolio Funds and to change the relative percentages among them or to add or eliminate funds. Such review will occur on at least an annual basis and will be reflected in the Portfolio Funds table disclosed in this prospectus.

Determination of Current Market State

Just as a thermostat may be set at different ranges for different seasons, the Fund’s allocation of assets between stock and bond funds is expected to be set at different range bands depending principally on the Investment Manager’s view of how expensive the equity market is compared to historical levels.

At least annually, the Investment Manager will conduct a review of the current equity market price levels compared to historical price levels, and will determine if the equity market is in an “expensive” state, or a “normal” state. This review will begin with a comparison of the S&P 500^® Index’s cyclically adjusted price-to-earnings ratio for the prior seven years against a 40-year history, but the Investment Manager will also take into account additional quantitative or qualitative market factors, including for example, trends in equity price measures and comparisons of equity prices against prices for other asset classes. Based on its determination of the current market state, the Investment Manager will select the form of allocation table to be effective in the Fund’s current prospectus. Also as part of this review, the Investment Manager will update the median historical information used in the table, and the resulting S&P 500^® Index levels used to create the bands around the median, regardless of the market state.

As noted below, the form of table used for an “expensive” market is expected to be different from that used for a “normal” market.

Generally, the Investment Manager will determine the current state of the equity market to be “expensive” when its analysis of the S&P 500^® Index’s cyclically adjusted price-to-earnings ratio for the prior seven years is within the top quartile of ratio observations over a 40-year history. The “expensive” equity market form of allocation table for the Fund is structured around an implied S&P 500^® Index trading range median of 50% stocks/50% bonds (the 50/50 Band), with allocations to bonds decreasing through stratified range bands below the 50/50 Band and allocations to bonds increasing through stratified range bands above the 50/50 Band, as shown by the following example:

“Expensive” Equity Market Form of Stock/Bond Allocation Table
Level of the S&P 500® Index	Stock Percentage	Bond Percentage
above top of trading range below	10%	90%
4% trading range above top of range below	15%	85%
4% trading range above top of range below	20%	80%
4% trading range above top of range below	25%	75%
4% trading range above top of range below	30%	70%

Prospectus 2022 7

Columbia Thermostat Fund^SM

Summary of the Fund (continued)

“Expensive” Equity Market Form of Stock/Bond Allocation Table
Level of the S&P 500® Index	Stock Percentage	Bond Percentage
4% trading range above top of range below	35%	65%
4% trading range above top of range below	40%	60%
4% trading range above top of range below	45%	55%
4% trading range centered on implied median (50/50 Band)*	50%	50%
4% trading range below bottom of range above	55%	45%
4% trading range below bottom of range above	60%	40%
4% trading range below bottom of range above	65%	35%
4% trading range below bottom of range above	70%	30%
4% trading range below bottom of range above	75%	25%
4% trading range below bottom of range above	80%	20%
4% trading range below bottom of range above	85%	15%
below bottom of trading range above	90%	10%

*Implied median price level as calculated by the Investment Manager.

The “expensive” form of table was in place from the Fund’s inception in 2002 through April 30, 2020 and is currently in place since May 1, 2021.

Generally, the Investment Manager will determine the current state of the equity market to be “normal” when its analysis of the S&P 500^® Index’s cyclically adjusted price-to-earnings ratio for the prior seven years is outside the top quartile of ratio observations over a 40-year history. The “normal” equity market form of allocation table for the Fund is also structured around the 50/50 Band, with allocations to bonds decreasing through stratified range bands below the 50/50 Band, and allocations to stocks and bonds set at 50% stocks/50% bonds for all trading levels above the 50/50 Band, as shown by the following example:

“Normal” Equity Market Form of Stock/Bond Allocation Table
Level of the S&P 500® Index	Stock Percentage	Bond Percentage
above trading range that is 2% below implied median (50/50 Band)*	50%	50%
4% trading range below bottom of range above	55%	45%
4% trading range below bottom of range above	60%	40%
4% trading range below bottom of range above	65%	35%
4% trading range below bottom of range above	70%	30%
4% trading range below bottom of range above	75%	25%
4% trading range below bottom of range above	80%	20%
4% trading range below bottom of range above	85%	15%
below bottom of trading range above	90%	10%

*Implied median price level as calculated by the Investment Manager.

The “normal” form of allocation table was in place from May 1, 2020 through April 30, 2021.

The Investment Manager will conduct the market state review at least annually prior to the annual updating of this prospectus, and may, in its discretion, assess the market state on an “emergency” basis and make any changes deemed necessary to reflect, for example, a very significant move in market levels or a structural change affecting the markets.

Any such “emergency” changes by the Investment Manager, which are expected to be infrequent, would be disclosed in this prospectus.

8 Prospectus 2022

Columbia Thermostat Fund^SM

Summary of the Fund (continued)

Principal Risks

An investment in the Fund involves risks, including general risks, as described below, relating to the Fund’s investment process and its “fund-of-funds” structure. An investment in the Fund also involves specific risks related to the individual Portfolio Funds, including but not limited to those described below, which in the aggregate are considered principal risks of investing in the Fund. More information about the Portfolio Funds, including their principal risks, is available in their prospectuses. This prospectus is not an offer for any of the Portfolio Funds. There is no assurance that the Fund will achieve its investment objective and you may lose money. The value of the Fund’s holdings may decline, and the Fund’s net asset value (NAV) and share price may go down. An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Allocation Risk. The Investment Manager uses an asset allocation strategy in pursuit of its investment objective, there is a risk that the Fund's allocation among asset classes or investments will cause the Fund's shares to lose value or cause the Fund to underperform other funds with similar investment objectives and/or strategies, or that the investments themselves will not produce the returns expected.

Fund-of-Funds Risk. Determinations regarding asset classes or Portfolio Funds and the Fund’s allocations thereto may not successfully achieve the Fund’s investment objective, in whole or in part. The selected Portfolio Funds’ performance may be lower than the performance of the asset class they were selected to represent or may be lower than the performance of alternative Portfolio Funds that could have been selected to represent the asset class. The Fund also is exposed to the same risks as the Portfolio Funds in direct proportion to the allocation of its assets among the Portfolio Funds. By investing in a combination of Portfolio Funds, the Fund has exposure to the risks of many areas of the market. The ability of the Fund to realize its investment objective will depend, in large part, on the extent to which the Portfolio Funds realize their investment objectives. There is no guarantee that the Portfolio Funds will achieve their respective investment objectives. The performance of Portfolio Funds could be adversely affected if other entities that invest in the same Portfolio Funds make relatively large investments or redemptions in such Portfolio Funds. The Fund, and its shareholders, indirectly bear a portion of the expenses of any funds in which the Fund invests. Because the expenses and costs of each Portfolio Fund are shared by its investors, redemptions by other investors in a Portfolio Fund could result in decreased economies of scale and increased operating expenses for such fund. These transactions might also result in higher brokerage, tax or other costs for a Portfolio Fund. This risk may be particularly important when one investor owns a substantial portion of a Portfolio Fund. The Investment Manager may have potential conflicts of interest in selecting affiliated funds over unaffiliated funds for investment by the Fund, and may also face potential conflicts of interest in selecting affiliated funds, because the fees the Investment Manager receives from some Portfolio Funds may be higher than the fees paid by other Portfolio Funds. Further, because of the Investment Manager’s confidence in its own strategies, investment philosophy and capacities, it will, in selecting Portfolio Funds, at times prefer a fund in the Columbia Acorn Family of Funds over alternative investments. There can be no assurance, however, that a fund in the Columbia Acorn Family of Funds selected for inclusion in Columbia Thermostat Fund’s portfolio will, in fact, outperform similar funds managed by the Investment Manager’s affiliates. Columbia Thermostat Fund currently invests only in affiliated Portfolio Funds. 

The Fund is subject indirectly to the risks of the Portfolio Funds described below. References to the “Fund” in the risk disclosures below refer to the Portfolio Funds and not Columbia Thermostat Fund. References to the “Investment Manager” in the risk disclosures below refer to the Fund's Investment Manager and/or Columbia Management as appropriate. Please see the Portfolio Funds Summary in the statutory prospectus for the Fund for information about the risks that apply to the Portfolio Funds. 

Market Risk. The Fund may incur losses due to declines in the value of one or more securities in which it invests. These declines may be due to factors affecting a particular issuer, or the result of, among other things, political, regulatory, market, economic or social developments affecting the relevant market(s) more generally. In addition, turbulence in financial markets and reduced liquidity in equity, credit and/or fixed income markets may negatively affect many issuers, which could adversely affect the Fund’s ability to price or value hard-to-value assets in thinly traded and closed markets and could cause significant redemptions and operational challenges. Global economies and financial markets are increasingly interconnected, and conditions and events in one country, region or financial 

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Columbia Thermostat Fund^SM

Summary of the Fund (continued)

market may adversely impact issuers in a different country, region or financial market. These risks may be magnified if certain events or developments adversely interrupt the global supply chain; in these and other circumstances, such risks might affect companies worldwide. As a result, local, regional or global events such as terrorism, war, other conflicts, natural disasters, disease/virus outbreaks and epidemics or other public health issues, recessions, depressions or other events – or the potential for such events – could have a significant negative impact on global economic and market conditions. 

The large-scale invasion of Ukraine by Russia in February 2022 has resulted in sanctions and market disruptions including declines in regional and global stock and commodity markets and significant devaluations of Russian currency. The extent and duration of the military action are impossible to predict but could be significant. Market disruption caused by the Russian military action, and any counter measures or responses thereto (including international sanctions, a downgrade in the country’s credit rating, purchasing and financing restrictions, boycotts, tariffs, changes in consumer or purchaser preferences, cyberattacks and espionage) could have severe adverse impacts on regional and/or global securities and commodities markets, including markets for oil and natural gas. These impacts may include reduced market liquidity, distress in credit markets, further disruption of global supply chains, increased risk of inflation, and limited access to investments in certain international markets and/or issuers. These developments and other related events could negatively impact Fund performance. 

The pandemic caused by coronavirus disease 2019 and its variants (COVID-19) has resulted in, and may continue to result in, significant global economic and societal disruption and market volatility due to disruptions in market access, resource availability, facilities operations, imposition of tariffs, export controls and supply chain disruption, among others. Such disruptions may be caused, or exacerbated by, quarantines and travel restrictions, workforce displacement and loss in human and other resources. The uncertainty surrounding the magnitude, duration, reach, costs and effects of the global pandemic, as well as actions that have been or could be taken by governmental authorities or other third parties, present unknowns that are yet to unfold. The impacts, as well as the uncertainty over impacts to come, of COVID-19 – and any other infectious illness outbreaks, epidemics and pandemics that may arise in the future – could negatively affect global economies and markets in ways that cannot necessarily be foreseen. In addition, the impact of infectious illness outbreaks and epidemics in less developed countries may be greater due to generally less established healthcare systems, governments and financial markets. Public health crises caused by the COVID-19 outbreak may exacerbate other pre-existing political, social and economic risks in certain countries or globally. The disruptions caused by COVID-19 could prevent the Fund from executing advantageous investment decisions in a timely manner and negatively impact the Fund’s ability to achieve its investment objective. Any such events could have a significant adverse impact on the value and risk profile of the Fund. 

Active Management Risk. Due to its active management, the Fund could underperform its benchmark index and/or other funds with similar investment objectives and/or strategies. 

Interest Rate Risk. Interest rate risk is the risk of losses attributable to changes in interest rates. In general, if prevailing interest rates rise, the values of loans and other debt instruments tend to fall, and if interest rates fall, the values of loans and other debt instruments tend to rise. Changes in the value of a debt instrument usually will not affect the amount of income the Fund receives from it but will generally affect the value of your investment in the Fund. Changes in interest rates may also affect the liquidity of the Fund’s investments in debt instruments. In general, the longer the maturity or duration of a debt instrument, the greater its sensitivity to changes in interest rates. Interest rate declines also may increase prepayments of debt obligations, which, in turn, would increase prepayment risk (the risk that the Fund will have to reinvest the money received in securities that have lower yields). Very low or negative interest rates may impact the Fund’s yield and may increase the risk that, if followed by rising interest rates, the Fund’s performance will be negatively impacted. The Fund is subject to the risk that the income generated by its investments may not keep pace with inflation. Actions by governments and central banking authorities can result in increases or decreases in interest rates. Higher periods of inflation could lead such authorities to raise interest rates. Such actions may negatively affect the value of debt instruments held by the Fund, resulting in a negative impact on the Fund's performance and NAV. Securities with floating interest rates are typically less sensitive to interest rate changes, but may decline in value if their interest rates do not rise as much as interest rates in general. Because rates on certain floating rate loans and other debt securities reset only periodically, 

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Columbia Thermostat Fund^SM

Summary of the Fund (continued)

changes in prevailing interest rates (and particularly sudden and significant changes) can be expected to cause fluctuations in the Fund’s NAV. Any interest rate increases could cause the value of the Fund’s investments in debt instruments to decrease. Rising interest rates may prompt redemptions from the Fund, which may force the Fund to sell investments at a time when it is not advantageous to do so, which could result in losses. 

Credit Risk. Credit risk is the risk that the value of loans or other debt instruments may decline if the issuer thereof defaults or otherwise becomes unable or unwilling, or is perceived to be unable or unwilling, to honor its financial obligations, such as making payments to the Fund when due. Various factors could affect the actual or perceived willingness or ability of the issuer to make timely interest or principal payments, including changes in the financial condition of the issuer or in general economic conditions. Credit rating agencies, such as S&P Global Ratings, Moody’s Investors Service, Inc. (Moody’s), Fitch Ratings, Inc. (Fitch), DBRS Morningstar (DBRS) and Kroll Bond Rating Agency, LLC (KBRA), assign credit ratings to certain debt instruments to indicate their credit risk. A rating downgrade by such agencies can negatively impact the value of such instruments. Lower-rated or unrated instruments held by the Fund may present increased credit risk as compared to higher-rated instruments. Non-investment grade debt instruments may be subject to greater price fluctuations and are more likely to experience a default than investment grade debt instruments and therefore may expose the Fund to increased credit risk. If the Fund purchases unrated instruments, or if the ratings of instruments held by the Fund are lowered after purchase, the Fund will depend on analysis of credit risk more heavily than usual. 

Preferred Stock Risk. Preferred stock is a type of stock that may pay dividends at a different rate than common stock of the same issuer, if at all, and that has preference over common stock in the payment of dividends and the liquidation of assets. Preferred stock does not ordinarily carry voting rights. The price of a preferred stock is generally determined by earnings, type of products or services, projected growth rates, experience of management, liquidity, and general market conditions of the markets on which the stock trades. The most significant risks associated with investments in preferred stock include issuer risk, market risk and interest rate risk (the risk of losses attributable to changes in interest rates). 

High-Yield Investments Risk. Securities and other debt instruments held by the Fund that are rated below investment grade (commonly called “high-yield” or “junk” bonds) and unrated debt instruments of comparable quality tend to be more sensitive to credit risk than higher-rated debt instruments and may experience greater price fluctuations in response to perceived changes in the ability of the issuing entity or obligor to pay interest and principal when due than to changes in interest rates. These investments are generally more likely to experience a default than higher-rated debt instruments. High-yield debt instruments are considered to be predominantly speculative with respect to the issuer’s capacity to pay interest and repay principal. These debt instruments typically pay a premium – a higher interest rate or yield – because of the increased risk of loss, including default. High-yield debt instruments may require a greater degree of judgment to establish a price, may be difficult to sell at the time and price the Fund desires, may carry high transaction costs, and also are generally less liquid than higher-rated debt instruments. The ratings provided by third party rating agencies are based on analyses by these ratings agencies of the credit quality of the debt instruments and may not take into account every risk related to whether interest or principal will be timely repaid. In adverse economic and other circumstances, issuers of lower-rated debt instruments are more likely to have difficulty making principal and interest payments than issuers of higher-rated debt instruments. 

Value Securities Risk. Value securities are securities of companies that may have experienced, for example, adverse business, industry or other developments or may be subject to special risks that have caused the securities to be out of favor and, in turn, potentially undervalued. The market value of a portfolio security may not meet the Portfolio Fund’s Investment Manager’s perceived value assessment of that security, or may decline in price, even though the Portfolio Fund’s Investment Manager believes the securities are already undervalued. There is also a risk that it may take longer than expected for the value of these investments to rise to the portfolio manager’s perceived value. In addition, value securities, at times, may not perform as well as growth securities or the stock market in general, and may be out of favor with investors for varying periods of time. 

Growth Securities Risk. Growth securities typically trade at a higher multiple of earnings than other types of equity securities. Accordingly, the market values of growth securities may never reach their expected market value and may decline in price. In addition, growth securities, at times, may not perform as well as value securities or the stock market in general, and may be out of favor with investors for varying periods of time. 

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Summary of the Fund (continued)

Sector Risk. At times, the Fund may have a significant portion of its assets invested in securities of companies conducting business within one or more economic sectors. Companies in the same sector may be similarly affected by economic, regulatory, political or market events or conditions, which may make the Fund more vulnerable to unfavorable developments in that sector than funds that invest more broadly. Generally, the more broadly the Fund invests, the more it spreads risk and potentially reduces the risks of loss and volatility. 

■ Consumer Discretionary Sector. The Fund is more susceptible to the particular risks that may affect companies in the consumer discretionary sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the consumer discretionary sector are subject to certain risks, including fluctuations in the performance of the overall domestic and international economy, interest rate changes, increased competition and consumer confidence. Performance of such companies may be affected by factors including reduced disposable household income, reduced consumer spending, and changing demographics and consumer tastes. 

■ Financial Services Sector. The Fund is more susceptible to the particular risks that may affect companies in the financial services sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the financial services sector are subject to certain risks, including the risk of regulatory change, decreased liquidity in credit markets and unstable interest rates. Such companies may have concentrated portfolios, such as a high level of loans to one or more industries or sectors, which makes them vulnerable to economic conditions that affect such industries or sectors. Performance of such companies may be affected by competitive pressures and exposure to investments, agreements and counterparties, including credit products that, under certain circumstances, may lead to losses (e.g., subprime loans). Companies in the financial services sector are subject to extensive governmental regulation that may limit the amount and types of loans and other financial commitments they can make, and the interest rates and fees they may charge. In addition, profitability of such companies is largely dependent upon the availability and the cost of capital. 

■ Information Technology Sector. The Fund is more susceptible to the particular risks that may affect companies in the information technology sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the information technology sector are subject to certain risks, including the risk that new services, equipment or technologies will not be accepted by consumers and businesses or will become rapidly obsolete. Performance of such companies may be affected by factors including obtaining and protecting patents (or the failure to do so) and significant competitive pressures, including aggressive pricing of their products or services, new market entrants, competition for market share and short product cycles due to an accelerated rate of technological developments. Such competitive pressures may lead to limited earnings and/or falling profit margins. As a result, the value of their securities may fall or fail to rise. In addition, many information technology sector companies have limited operating histories and prices of these companies’ securities historically have been more volatile than other securities, especially over the short term. Some companies in the information technology sector are facing increased government and regulatory scrutiny and may be subject to adverse government or regulatory action, which could negatively impact the value of their securities. 

Foreign Securities Risk. Investments in or exposure to securities of foreign companies may involve heightened risks relative to investments in or exposure to securities of U.S. companies. For example, foreign markets can be extremely volatile. Foreign securities may also be less liquid, making them more difficult to trade, than securities of U.S. companies so that the Fund may, at times, be unable to sell foreign securities at desirable times or prices. Brokerage commissions, custodial costs and other fees are also generally higher for foreign securities. The Fund may have limited or no legal recourse in the event of default with respect to certain foreign securities, including those issued by foreign governments. In addition, foreign governments may impose withholding or other taxes on the Fund’s income, capital gains or proceeds from the disposition of foreign securities, which could reduce the Fund’s return on such securities. In some cases, such withholding or other taxes could potentially be confiscatory. Other risks include: possible delays in the settlement of transactions or in the payment of income; generally less publicly available information about foreign companies; the impact of economic, political, social, diplomatic or other conditions or events (including, for example, military confrontations and actions, war, other conflicts, terrorism and disease/virus outbreaks and epidemics), possible seizure, expropriation or nationalization of a company or its assets or the assets of a particular investor or category of investors; accounting, auditing and financial reporting standards that may be less comprehensive and stringent than those applicable to domestic companies; the imposition of economic and 

12 Prospectus 2022

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Summary of the Fund (continued)

other sanctions against a particular foreign country, its nationals or industries or businesses within the country; and the generally less stringent standard of care to which local agents may be held in the local markets. In addition, it may be difficult to obtain reliable information about the securities and business operations of certain foreign issuers. Governments or trade groups may compel local agents to hold securities in designated depositories that are not subject to independent evaluation. The less developed a country’s securities market is, the greater the level of risks. Economic sanctions may be, and have been, imposed against certain countries, organizations, companies, entities and/or individuals. Economic sanctions and other similar governmental actions could, among other things, effectively restrict or eliminate the Fund’s ability to purchase or sell securities, and thus may make the Fund’s investments in such securities less liquid or more difficult to value. In addition, as a result of economic sanctions, the Fund may be forced to sell or otherwise dispose of investments at inopportune times or prices, which could result in losses to the Fund and increased transaction costs. These conditions may be in place for a substantial period of time and enacted with limited advance notice to the Fund. The risks posed by sanctions against a particular foreign country, its nationals or industries or businesses within the country may be heightened to the extent the Fund invests significantly in the affected country or region or in issuers from the affected country that depend on global markets. Additionally, investments in certain countries may subject the Fund to a number of tax rules, the application of which may be uncertain. Countries may amend or revise their existing tax laws, regulations and/or procedures in the future, possibly with retroactive effect. Changes in or uncertainties regarding the laws, regulations or procedures of a country could reduce the after-tax profits of the Fund, directly or indirectly, including by reducing the after-tax profits of companies located in such countries in which the Fund invests, or result in unexpected tax liabilities for the Fund. 

Operational and Settlement Risks of Foreign Securities. The Fund’s foreign securities are generally held outside the United States in the primary market for the securities in the custody of certain eligible foreign banks and trust companies (“foreign sub-custodians”), as permitted under the Investment Company Act of 1940 (the 1940 Act). Settlement practices for foreign securities may differ from those in the United States. Some countries have limited governmental oversight and regulation of industry practices, stock exchanges, depositories, registrars, brokers and listed companies, which increases the risk of corruption and fraud and the possibility of losses to the Fund. In particular, under certain circumstances, foreign securities may settle on a delayed delivery basis, meaning that the Fund may be required to make payment for securities before the Fund has actually received delivery of the securities or deliver securities prior to the receipt of payment. Typically, in these cases, the Fund will receive evidence of ownership in accordance with the generally accepted settlement practices in the local market entitling the Fund to delivery or payment at a future date, but there is a risk that the security will not be delivered to the Fund or that payment will not be received, although the Fund and its foreign sub-custodians take reasonable precautions to mitigate this risk. Losses can also result from lost, stolen or counterfeit securities; defaults by brokers and banks; failures or defects of the settlement system; or poor and improper record keeping by registrars and issuers. 

Share Blocking. Share blocking refers to a practice in certain foreign markets under which an issuer’s securities are blocked from trading at the custodian or sub-custodian level for a specified number of days before and, in certain instances, after a shareholder meeting where a vote of shareholders takes place. The blocking period can last up to several weeks. Share blocking may prevent the Fund from buying or selling securities during this period, because during the time shares are blocked, trades in such securities will not settle. It may be difficult or impossible to lift blocking restrictions, with the particular requirements varying widely by country. As a consequence of these restrictions, the Portfolio Fund's Investment Manager, on behalf of the Fund, may abstain from voting proxies in markets that require share blocking. 

Emerging Market Securities Risk. Securities issued by foreign governments or companies in emerging market countries, such as China, Russia and certain countries in Eastern Europe, the Middle East, Asia, Latin America or Africa, are more likely to have greater exposure to the risks of investing in foreign securities that are described in Foreign Securities Risk. In addition, emerging market countries are more likely to experience instability resulting, for example, from rapid changes or developments in social, political, economic or other conditions. Their economies are usually less mature and their securities markets are typically less developed with more limited trading activity (i.e., lower trading volumes and less liquidity) than more developed countries. Emerging market securities tend to be more volatile, and may be more susceptible to market manipulation, than securities in more developed markets. Many emerging market countries are heavily dependent on international trade and have fewer trading partners, which 

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Columbia Thermostat Fund^SM

Summary of the Fund (continued)

makes them more sensitive to world commodity prices and economic downturns in other countries. Some emerging market countries have a higher risk of currency devaluations, and some of these countries may experience periods of high inflation or rapid changes in inflation rates and may have hostile relations with other countries. Due to the differences in the nature and quality of financial information of issuers of emerging market securities, including auditing and financial reporting standards, financial information and disclosures about such issuers may be unavailable or, if made available, may be considerably less reliable than publicly available information about other foreign securities. 

Operational and Settlement Risks of Securities in Emerging Markets. In addition to having less developed securities markets, banks in emerging markets that are eligible foreign sub-custodians may be recently organized, lack extensive operating experience or lack effective government oversight or regulation. In addition, there may be legal restrictions or limitations on the ability of the Fund to recover assets held in custody by a foreign sub-custodian in the event of the bankruptcy of the sub-custodian. Because settlement systems may be less organized than in developed markets and because delivery versus payment settlement may not be possible or reliable, there may be a greater risk that settlement may be delayed and that cash or securities of the Fund may be lost because of failures of or defects in the system, including fraud or corruption. Settlement systems in emerging markets also have a higher risk of failed trades. 

Risks Related to Currencies and Corporate Actions in Emerging Markets. Risks related to currencies and corporate actions are also greater in emerging market countries than in developed countries. For example, some emerging market countries may have fixed or managed currencies that are not free-floating against the U.S. dollar. Further, certain currencies may not have an active trading market internationally, or countries may have varying exchange rates. Some emerging market countries have a higher risk of currency devaluations, and some of these countries may experience sustained periods of high inflation or rapid changes in inflation rates which can have negative effects on a country’s economy and securities markets. Corporate action procedures in emerging market countries may be less reliable and have limited or no involvement by the depositories and central banks. Lack of standard practices and payment systems can lead to significant delays in payment. 

Risks Related to Corporate and Securities Laws in Emerging Markets. Securities laws in emerging markets may be relatively new and unsettled and, consequently, there is a risk of rapid and unpredictable change in laws regarding foreign investment, securities regulation, title to securities and shareholder rights. Accordingly, foreign investors may be adversely affected by new or amended laws and regulations. In addition, the systems of corporate governance to which issuers in certain emerging markets are subject may be less advanced than the systems to which issuers located in more developed countries are subject, and therefore, shareholders of such issuers may not receive many of the protections available to shareholders of issuers located in more developed countries. These risks may be heightened in China and Russia. 

Sovereign Debt Risk. The willingness or ability of a sovereign or quasi-sovereign debtor to repay principal and pay interest in a timely manner may be affected by a variety of factors, including its cash flow situation, the extent of its reserves, the availability of sufficient foreign exchange on the date a payment is due, the relative size of the debt service burden to the economy as a whole, the sovereign or quasi-sovereign debtor’s policy toward international lenders, and the political constraints to which such debtor may be subject. 

With respect to sovereign or quasi-sovereign debt of emerging market issuers, investors should be aware that certain emerging market countries are among the largest debtors to commercial banks and foreign governments. At times, certain emerging market countries have declared moratoria on the payment of principal and interest on external debt. Certain emerging market countries have experienced difficulty in servicing their sovereign or quasi-sovereign debt on a timely basis and that has led to defaults and the restructuring of certain indebtedness to the detriment of debt-holders. 

Foreign Currency Risk. The performance of the Fund may be materially affected positively or negatively by foreign currency strength or weakness relative to the U.S. dollar, particularly if the Fund invests a significant percentage of its assets in foreign securities or other assets denominated in currencies other than the U.S. dollar. Currency rates in foreign countries may fluctuate significantly over short or long periods of time for a number of reasons, including changes in interest rates, imposition of currency controls and economic or political developments in the U.S. or 

14 Prospectus 2022

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Summary of the Fund (continued)

abroad. The Fund may also incur currency conversion costs when converting foreign currencies into U.S. dollars and vice versa. Restrictions on currency trading may be imposed by foreign countries, which may adversely affect the value of your investment in the Fund. Even though the currencies of some countries may be pegged to the U.S. dollar, the conversion rate may be controlled by government regulation or intervention at levels significantly different than what would normally prevail in a free market. Significant revaluations of the U.S. dollar exchange rate of these currencies could cause substantial reductions in the Fund’s NAV. 

Liquidity and Trading Volume Risk. Due to market conditions, including uncertainty regarding the price of a security, it may be difficult for the Fund to buy or sell portfolio securities at a desirable time or price, which could result in investment losses. This risk of portfolio illiquidity is heightened with respect to small- and mid-cap securities, generally, and foreign small- and mid-cap securities in particular. The Fund may have to lower the selling price, liquidate other investments, or forego another, more appealing investment opportunity as a result of illiquidity in the markets. The Investment Manager will fair value in good faith any securities it deems to be illiquid under consistently applied procedures established by the Fund’s Board. Market conditions are always changing and vary by country and industry sector, and investing in international markets involves unique risks. Although it is difficult to accurately assess trends in trading volumes in foreign markets, a reduction in trading volumes poses challenges to the Fund. This is particularly so because the Fund focuses on small- and mid-cap companies that usually have lower trading volumes and often takes sizeable positions in portfolio companies. As a result of lower trading volumes, it may take longer to buy or sell securities, which can exacerbate the Fund’s exposure to volatile markets. The Fund may also be limited in its ability to execute favorable trades in portfolio securities in response to changes in share prices and fundamentals. If the Fund is forced to sell securities to meet redemption requests or other cash needs, or in the case of an event affecting liquidity in a particular market or markets, it may be forced to dispose of those securities under disadvantageous circumstances and at a loss. As the Fund grows in size or, conversely, if it faces significant redemption pressure, these considerations take on increasing significance and may adversely impact performance. 

Focused Portfolio Risk. Because the Fund may invest in a limited number of companies, the Fund as a whole is subject to greater risk of loss if any of those securities decline in price. 

Issuer Risk. An issuer in which the Fund invests or to which it has exposure may perform poorly or below expectations, and the value of its securities may therefore decline, which may negatively affect the Fund’s performance. Underperformance of an issuer may be caused by poor management decisions, competitive pressures, breakthroughs in technology, reliance on suppliers, labor problems or shortages, corporate restructurings, fraudulent disclosures, natural disasters, military confrontations and actions, war, terrorism, disease/virus outbreaks, epidemics or other events, conditions and factors which may impair the value of an investment in the Fund. 

■ Small- and Mid-Cap Stock Risk. Investments in small- and mid-capitalization companies (small- and mid-cap companies) often involve greater risks than investments in larger, more established companies (larger companies) because small- and mid-cap companies tend to have less predictable earnings and may lack the management experience, financial resources, product diversification and competitive strengths of larger companies. Securities of small- and mid-cap companies may be less liquid and more volatile than the securities of larger companies. 

■ Large-Cap Stock Risk. Investments in larger, more established companies (larger companies) may involve certain risks associated with their larger size. For instance, larger companies may be less able to respond quickly to new competitive challenges, such as changes in consumer tastes or innovation from smaller competitors. Also, larger companies are sometimes less able to achieve as high growth rates as successful smaller companies, especially during extended periods of economic expansion. 

U.S. Government Obligations Risk. While U.S. Treasury obligations are backed by the “full faith and credit” of the U.S. Government, such securities are nonetheless subject to credit risk (i.e., the risk that the U.S. Government may be, or may be perceived to be, unable or unwilling to honor its financial obligations, such as making payments). Securities issued or guaranteed by federal agencies or authorities and U.S. Government-sponsored instrumentalities or enterprises may or may not be backed by the full faith and credit of the U.S. Government. For example, securities issued by the Federal Home Loan Mortgage Corporation, the Federal National Mortgage Association and the Federal 

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Summary of the Fund (continued)

Home Loan Banks are neither insured nor guaranteed by the U.S. Government. These securities may be supported by the ability to borrow from the U.S. Treasury or only by the credit of the issuing agency, authority, instrumentality or enterprise and, as a result, are subject to greater credit risk than securities issued or guaranteed by the U.S. Treasury. 

Derivatives Risk. Derivatives may involve significant risks. Derivatives are financial instruments, traded on an exchange or in the over-the-counter (OTC) markets, with a value in relation to, or derived from, the value of an underlying asset(s) (such as a security, commodity or currency) or other reference, such as an index, rate or other economic indicator (each an underlying reference). Derivatives may include those that are privately placed or otherwise exempt from SEC registration, including certain Rule 144A eligible securities. Derivatives could result in Fund losses if the underlying reference does not perform as anticipated. Use of derivatives is a highly specialized activity that can involve investment techniques, risks, and tax planning different from those associated with more traditional investment instruments. The Fund’s derivatives strategy may not be successful and use of certain derivatives could result in substantial, potentially unlimited, losses to the Fund regardless of the Fund’s actual investment. A relatively small movement in the price, rate or other economic indicator associated with the underlying reference may result in substantial losses for the Fund. Derivatives may be more volatile than other types of investments. Derivatives can increase the Fund’s risk exposure to underlying references and their attendant risks, including the risk of an adverse credit event associated with the underlying reference (credit risk), the risk of an adverse movement in the value, price or rate of the underlying reference (market risk), the risk of an adverse movement in the value of underlying currencies (foreign currency risk) and the risk of an adverse movement in underlying interest rates (interest rate risk). Derivatives may expose the Fund to additional risks, including the risk of loss due to a derivative position that is imperfectly correlated with the underlying reference it is intended to hedge or replicate (correlation risk), the risk that a counterparty will fail to perform as agreed (counterparty risk), the risk that a hedging strategy may fail to mitigate losses, and may offset gains (hedging risk), the risk that the return on an investment may not keep pace with inflation (inflation risk), the risk that losses may be greater than the amount invested (leverage risk), the risk that the Fund may be unable to sell an investment at an advantageous time or price (liquidity risk), the risk that the investment may be difficult to value (pricing risk), and the risk that the price or value of the investment fluctuates significantly over short periods of time (volatility risk). The value of derivatives may be influenced by a variety of factors, including national and international political and economic developments. Potential changes to the regulation of the derivatives markets may make derivatives more costly, may limit the market for derivatives, or may otherwise adversely affect the value or performance of derivatives. 

Derivatives Risk – Forward Contracts Risk. A forward contract is an over-the-counter derivative transaction between two parties to buy or sell a specified amount of an underlying reference at a specified price (or rate) on a specified date in the future. Forward contracts are negotiated on an individual basis and are not standardized or traded on exchanges. The market for forward contracts is substantially unregulated (there is no limit on daily price movements and speculative position limits are not applicable). The principals who deal in certain forward contract markets are not required to continue to make markets in the underlying references in which they trade and these markets can experience periods of illiquidity, sometimes of significant duration. There have been periods during which certain participants in forward contract markets have refused to quote prices for certain underlying references or have quoted prices with an unusually wide spread between the price at which they were prepared to buy and that at which they were prepared to sell. At or prior to maturity of a forward contract, the Fund may enter into an offsetting contract and may incur a loss to the extent there has been adverse movement in forward contract prices. The liquidity of the markets for forward contracts depends on participants entering into offsetting transactions rather than making or taking delivery. To the extent participants make or take delivery, liquidity in the market for forwards could be reduced. A relatively small price movement in a forward contract may result in substantial losses to the Fund, exceeding the amount of the margin paid. Forward contracts can increase the Fund’s risk exposure to underlying references and their attendant risks, such as credit risk, market risk, foreign currency risk and interest rate risk, while also exposing the Fund to correlation risk, counterparty risk, hedging risk, inflation risk, leverage risk, liquidity risk, pricing risk and volatility risk. 

■ A forward foreign currency contract is a derivative (forward contract) in which the underlying reference is a country's or region’s currency. The Fund may agree to buy or sell a country's or region’s currency at a specific 

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Summary of the Fund (continued)

price on a specific date in the future. These instruments may fall in value (sometimes dramatically) due to foreign market downswings or foreign currency value fluctuations, subjecting the Fund to foreign currency risk (the risk that Fund performance may be negatively impacted by foreign currency strength or weakness relative to the U.S. dollar, particularly if the Fund exposes a significant percentage of its assets to currencies other than the U.S. dollar). Unanticipated changes in the currency markets could result in reduced performance for the Fund. When the Fund converts its foreign currencies into U.S. dollars, it may incur currency conversion costs due to the spread between the prices at which it may buy and sell various currencies in the market. 

Derivatives Risk – Futures Contracts Risk. A futures contract is an exchange-traded derivative transaction between two parties in which a buyer (holding the “long” position) agrees to pay a fixed price (or rate) at a specified future date for delivery of an underlying reference from a seller (holding the “short” position). The seller hopes that the market price on the delivery date is less than the agreed upon price, while the buyer hopes for the contrary. Certain futures contract markets are highly volatile, and futures contracts may be illiquid. Futures exchanges may limit fluctuations in futures contract prices by imposing a maximum permissible daily price movement. The Fund may be disadvantaged if it is prohibited from executing a trade outside the daily permissible price movement. At or prior to maturity of a futures contract, the Fund may enter into an offsetting contract and may incur a loss to the extent there has been adverse movement in futures contract prices. The liquidity of the futures markets depends on participants entering into offsetting transactions rather than making or taking delivery. To the extent participants make or take delivery, liquidity in the futures market could be reduced. Positions in futures contracts may be closed out only on the exchange on which they were entered into or through a linked exchange, and no secondary market exists for such contracts. Futures positions are marked to market each day and variation margin payment must be paid to or by the Fund. Because of the low margin deposits normally required in futures trading, it is possible that the Fund may employ a high degree of leverage in the portfolio. As a result, a relatively small price movement in a futures contract may result in substantial losses to the Fund, exceeding the amount of the margin paid. For certain types of futures contracts, losses are potentially unlimited. Futures markets are highly volatile and the use of futures may increase the volatility of the Fund’s NAV. Futures contracts executed (if any) on foreign exchanges may not provide the same protection as U.S. exchanges. Futures contracts can increase the Fund’s risk exposure to underlying references and their attendant risks, such as credit risk, market risk, foreign currency risk, and interest rate risk, while also exposing the Fund to correlation risk, counterparty risk, hedging risk, inflation risk, leverage risk, liquidity risk, pricing risk and volatility risk. 

■ An interest rate future is a derivative that is an agreement whereby the buyer and seller agree to the future delivery of an interest-bearing instrument on a specific date at a pre-determined price. Examples include Treasury-bill futures, Treasury-bond futures and Eurodollar futures. 

Derivatives Risk – Options Risk. Options are derivatives that give the purchaser the option to buy (call) or sell (put) an underlying reference from or to a counterparty at a specified price (the strike price) on or before an expiration date. When writing options, the Fund is exposed to the risk that it may be required to buy or sell the underlying reference at a disadvantageous price on or before the expiration date. Options may involve economic leverage, which could result in greater volatility in price movement. The Fund's losses could be significant, and are potentially unlimited for certain types of options. Options may be traded on a securities exchange or in the over-the-counter market. At or prior to maturity of an options contract, the Fund may enter into an offsetting contract and may incur a loss to the extent there has been adverse movement in options prices. Options can increase the Fund’s risk exposure to underlying references and their attendant risks such as credit risk, market risk, foreign currency risk and interest rate risk, while also exposing the Fund to correlation risk, counterparty risk, hedging risk, inflation risk, leverage risk, liquidity risk, pricing risk and volatility risk. 

Derivatives Risk – Swaps Risk. In a typical swap transaction, two parties agree to exchange the return earned on a specified underlying reference for a fixed return or the return from another underlying reference during a specified period of time. Swaps may be difficult to value and may be illiquid. Swaps could result in Fund losses if the underlying asset or reference does not perform as anticipated. Swaps create significant investment leverage such that a relatively small price movement in a swap may result in immediate and substantial losses to the Fund. The Fund may only close out a swap with its particular counterparty, and may only transfer a position with the consent of that counterparty. Certain swaps, such as short swap transactions and total return swaps, have the potential for 

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Summary of the Fund (continued)

unlimited losses, regardless of the size of the initial investment. Swaps can increase the Fund’s risk exposure to underlying references and their attendant risks, such as credit risk, market risk, foreign currency risk and interest rate risk, while also exposing the Fund to correlation risk, counterparty risk, hedging risk, inflation risk, leverage risk, liquidity risk, pricing risk and volatility risk. 

■ A credit default swap (including a swap on a credit default index, sometimes referred to as a credit default swap index) is a derivative and special type of swap where one party pays, in effect, an insurance premium through a stream of payments to another party in exchange for the right to receive a specified return upon the occurrence of a particular credit event by one or more third parties, such as bankruptcy, default or a similar event. A credit default swap may be embedded within a structured note or other derivative instrument. Credit default swaps enable an investor to buy or sell protection against such a credit event (such as an issuer’s bankruptcy, restructuring or failure to make timely payments of interest or principal). Credit default swap indices are indices that reflect the performance of a basket of credit default swaps and are subject to the same risks as credit default swaps. If such a default were to occur, any contractual remedies that the Fund may have may be subject to bankruptcy and insolvency laws, which could delay or limit the Fund's recovery. Thus, if the counterparty under a credit default swap defaults on its obligation to make payments thereunder, as a result of its bankruptcy or otherwise, the Fund may lose such payments altogether, or collect only a portion thereof, which collection could involve costs or delays. The Fund’s return from investment in a credit default swap index may not match the return of the referenced index. Further, investment in a credit default swap index could result in losses if the referenced index does not perform as expected. Unexpected changes in the composition of the index may also affect performance of the credit default swap index. If a referenced index has a dramatic intraday move that causes a material decline in the Fund’s net assets, the terms of the Fund’s credit default swap index may permit the counterparty to immediately close out the transaction. In that event, the Fund may be unable to enter into another credit default swap index or otherwise achieve desired exposure, even if the referenced index reverses all or a portion of its intraday move. 

Derivatives Risk – Swaptions Risk. A swaption is an options contract on a swap agreement. These transactions give the purchasing party the right (but not the obligation) to enter into new swap agreements or to shorten, extend, cancel or otherwise modify an existing swap agreement at some designated future time on specified terms, in return for payment of the purchase price (the “premium”) of the option. The Fund may write (sell) and purchase put and call swaptions to the same extent it may make use of standard options on securities or other instruments. The writer of the contract receives the premium and bears the risk of unfavorable changes in the market value on the underlying swap agreement. Swaptions can be bundled and sold as a package. These are commonly called interest rate caps, floors and collars. 

Convertible Securities Risk. Convertible securities are subject to the usual risks associated with debt instruments, such as interest rate risk (the risk of losses attributable to changes in interest rates) and credit risk (the risk that the issuer of a debt instrument will default or otherwise become unable, or be perceived to be unable or unwilling, to honor a financial obligation, such as making payments to the Fund when due). Convertible securities also react to changes in the value of the common stock into which they convert, and are thus subject to market risk (the risk that the market values of securities or other investments that the Fund holds will fall, sometimes rapidly or unpredictably, or fail to rise). Because the value of a convertible security can be influenced by both interest rates and the common stock's market movements, a convertible security generally is not as sensitive to interest rates as a similar debt instrument, and generally will not vary in value in response to other factors to the same extent as the underlying common stock. In the event of a liquidation of the issuing company, holders of convertible securities would typically be paid before the company's common stockholders but after holders of any senior debt obligations of the company. The Fund may be forced to convert a convertible security before it otherwise would choose to do so, which may decrease the Fund's return. 

Forward Commitments on Mortgage-Backed Securities (including Dollar Rolls) Risk. When purchasing mortgage-backed securities in the “to be announced” (TBA) market (MBS TBAs), the seller agrees to deliver mortgage-backed securities for an agreed upon price on an agreed upon date, but may make no guarantee as to the specific securities to be delivered. In lieu of taking delivery of mortgage-backed securities, the Fund could enter into dollar rolls, which are transactions in which the Fund sells securities to a counterparty and simultaneously agrees to purchase those or 

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Summary of the Fund (continued)

similar securities in the future at a predetermined price. Dollar rolls involve the risk that the market value of the securities the Fund is obligated to repurchase may decline below the repurchase price, or that the counterparty may default on its obligations. These transactions may also increase the Fund’s portfolio turnover rate. If the Fund reinvests the proceeds of the security sold, the Fund will also be subject to the risk that the investments purchased with such proceeds will decline in value (a form of leverage risk). MBS TBAs and dollar rolls are subject to the risk that the counterparty to the transaction may not perform or be unable to perform in accordance with the terms of the instrument. 

Stripped Securities Risk. Stripped securities are the separate income or principal components of debt securities. These securities are particularly sensitive to changes in interest rates, and therefore subject to greater fluctuations in price than typical interest bearing debt securities. For example, stripped mortgage-backed securities have greater interest rate risk than mortgage-backed securities with like maturities, and stripped treasury securities have greater interest rate risk (the risk of losses attributable to changes in interest rates) than traditional government securities with identical credit ratings. 

Prepayment and Extension Risk. Prepayment and extension risk is the risk that a bond or other security or investment might, in the case of prepayment risk, be called or otherwise converted, prepaid or redeemed before maturity and, in the case of extension risk, that the investment might not be called as expected. In the case of prepayment risk, if the investment is converted, prepaid or redeemed before maturity, the portfolio managers may not be able to invest the proceeds in other investments providing as high a level of income, resulting in a reduced yield to the Fund. In the case of mortgage- or other asset-backed securities, as interest rates decrease or spreads narrow, the likelihood of prepayment increases. Conversely, extension risk is the risk that an unexpected rise in interest rates will extend the life of a mortgage- or other asset-backed security beyond the prepayment time. If the Fund's investments are locked in at a lower interest rate for a longer period of time, the portfolio managers may be unable to capitalize on securities with higher interest rates or wider spreads. 

Reinvestment Risk. Reinvestment risk arises when the Fund is unable to reinvest income or principal at the same or at least the same return it is currently earning. 

Depositary Receipts Risk. Depositary receipts are receipts issued by a bank or trust company reflecting ownership of underlying securities issued by foreign companies. Some foreign securities are traded in the form of American Depositary Receipts and/or Global Depositary Receipts. Depositary receipts involve risks similar to the risks associated with investments in foreign securities, including those associated with an issuer’s (and any of its related companies’) country of organization and places of business operations, which may be related to the particular political, regulatory, economic, social and other conditions or events (including, for example, military confrontations and actions, war, terrorism and disease/virus outbreaks and epidemics) occurring in the country and fluctuations in such country’s currency, as well as market risk tied to the underlying foreign company. In addition, holders of depositary receipts may have limited voting rights, may not have the same rights afforded to stockholders of a typical domestic company in the event of a corporate action, such as an acquisition, merger or rights offering, and may experience difficulty in receiving company stockholder communications. There is no guarantee that a financial institution will continue to sponsor a depositary receipt, or that a depositary receipt will continue to trade on an exchange, either of which could adversely affect the liquidity, availability and pricing of the depositary receipt. Changes in foreign currency exchange rates will affect the value of depositary receipts and, therefore, may affect the value of your investment in the Fund. 

Changing Distribution Level Risk. The Fund normally expects to receive income which may include interest, dividends and/or capital gains, depending upon its investments. The distribution amounts paid by the Fund will vary and generally depend on the amount of income the Fund earns (less expenses) on its portfolio holdings, and capital gains or losses it recognizes. A decline in the Fund’s income or net capital gains arising from its investments may reduce its distribution level. 

Geographic Focus Risk. The Fund may be particularly susceptible to risks related to economic, political, regulatory or other events or conditions affecting issuers and countries within the specific geographic regions in which the Fund invests. The Fund’s NAV may be more volatile than the NAV of a more geographically diversified fund. 

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Summary of the Fund (continued)

■ Asia Pacific Region. A number of countries in the Asia Pacific region are considered underdeveloped or developing, including from a political, economic and/or social perspective, and may have relatively unstable governments and economies based on limited business, industries and/or natural resources or commodities. Events in any one country within the region may impact that country, other countries in the region or the region as a whole. As a result, events in the region will generally have a greater effect on the Fund than if the Fund were more geographically diversified in a region with more developed countries and economies. This could result in increased volatility in the value of the Fund’s investments and losses for the Fund. Continued growth of economies and securities markets in the region will require sustained economic and fiscal discipline, as well as continued commitment to governmental and regulatory reforms. Development also may be influenced by international economic conditions, including those in the United States and Japan, and by world demand for goods or natural resources produced in countries in the Asia Pacific region. Securities markets in the region are generally smaller and have a lower trading volume than those in the United States, which may result in the securities of some companies in the region being less liquid than U.S. or other foreign securities. Some currencies, inflation rates or interest rates in the Asia Pacific region are or can be volatile, and some countries in the region may restrict the flow of money in and out of the country. The risks described under “Emerging Market Securities Risk” and  “Foreign Securities Risk” may be more pronounced due to the Fund’s focus on investments in the region. 

■ Greater China. The Greater China region consists of Hong Kong, The People's Republic of China and Taiwan, among other countries, and the Fund's investments in the region are particularly susceptible to risks in that region. The Hong Kong, Taiwanese, and Chinese economies are dependent on the economies of other countries and can be significantly affected by currency fluctuations and increasing competition from other emerging economies in Asia with lower costs. Adverse events in any one country within the region may impact the other countries in the region or Asia as a whole. As a result, adverse events in the region will generally have a greater effect on the Fund than if the Fund were more geographically diversified, which could result in greater volatility in the Fund’s NAV and losses. Markets in the Greater China region can experience significant volatility due to social, economic, regulatory and political uncertainties. Changes in Chinese government policy and economic growth rates could significantly affect local markets and the entire Greater China region. China has yet to develop comprehensive securities, corporate, or commercial laws, its market is relatively new and less developed, and its economy is experiencing a relative slowdown. Export growth continues to be a major driver of China’s economic growth. As a result, a reduction in spending on Chinese products and services, the institution of additional tariffs or other trade barriers, including as a result of heightened trade tensions between China and the United States, or a downturn in any of the economies of China’s key trading partners may have an adverse impact on the Chinese economy. Many Chinese companies to which the Fund seeks investment exposure use a structure known as a variable interest entity (a VIE) to address Chinese restrictions on direct foreign investment in Chinese companies operating in certain sectors. The Fund’s investment exposure to VIEs may pose additional risks because the Fund’s investment is not made directly in the VIE (the actual Chinese operating company), but rather in a holding company domiciled outside of China (a Holding Company) whose interests in the business of the underlying Chinese operating company (the VIE) are established through contracts rather than through equity ownership. The VIE (which the Fund is restricted from owning under Chinese law) is generally owned by Chinese nationals, and the Holding Company (in which the Fund invests) holds only contractual rights (rather than equity ownership) relating to the VIE, typically including a contractual claim on the VIE's profits. Shares of the Holding Company, in turn, are traded on exchanges outside of China and are available to non-Chinese investors such as the Fund. The VIE structure is a longstanding practice in China but, until recently, was not acknowledged by the Chinese government, creating uncertainty over the possibility that the Chinese government might cease to tolerate VIE structures at any time or impose new restrictions on the structure. In such a scenario, the Chinese operating company could be subject to penalties, including revocation of its business and operating license, or the Holding Company could forfeit its interest in the business of the Chinese operating company. Further, in case of a dispute, the remedies and rights of the Fund may be limited, and such legal uncertainty may be exploited against the interests of the Fund. Control over a VIE may also be jeopardized if a natural person who holds the equity interest in the VIE breaches the terms of the contractual arrangements, is subject to legal proceedings, or if any physical instruments or property of the VIE, such as seals, business registration certificates, financial data and licensing arrangements (sometimes referred to as “chops”), are used without authorization. In the event of such an occurrence, the Fund, as a foreign investor, 

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Summary of the Fund (continued)

may have little or no legal recourse. In addition to the risk of government intervention, investments through a VIE structure are subject to the risk that the China-based company (or its officers, directors, or Chinese equity owners) may breach the contractual arrangements, or Chinese law changes in a way that adversely affects the enforceability of the arrangements, or the contracts are otherwise not enforceable under Chinese law, in which case a Fund may suffer significant losses on its investments through a VIE structure with little or no recourse available. The Fund will typically have little or no ability to influence the VIE through proxy voting or other means because it is not a VIE owner/shareholder. Foreign companies listed on stock exchanges in the United States, including companies using the VIE structure, could also face delisting or other ramifications for failure to meet the expectations and/or requirements of the SEC, the Public Company Accounting Oversight Board, or other U.S. regulators. Recently, however, China has proposed the adoption of rules which would affirm that VIEs are legally permissible, though there remains significant uncertainty over how these rules will operate. Any of these risks could reduce the liquidity and value of the Fund’s investments in Holding Companies or render them valueless. 

Real Estate-Related Investment Risk. Investments in real estate investment trusts (REITs) and in securities of other companies (wherever organized) principally engaged in the real estate industry subject the Fund to, among other things, risks similar to those of direct investments in real estate and the real estate industry in general. These include risks related to general and local economic conditions, possible lack of availability of financing and changes in interest rates or property values. The value of interests in a REIT may be affected by, among other factors, changes in the value of the underlying properties owned by the REIT, changes in the prospect for earnings and/or cash flow growth of the REIT itself, defaults by borrowers or tenants, market saturation, decreases in market rates for rents, and other economic, political, or regulatory matters affecting the real estate industry, including REITs. REITs may be subject to more abrupt or erratic price movements than the overall securities markets. REITs are also subject to the risk of failing to qualify for favorable tax treatment under the Internal Revenue Code of 1986, as amended. The failure of a REIT to continue to qualify as a REIT for tax purposes can materially and adversely affect its value. Some REITs (especially mortgage REITs) are affected by risks similar to those associated with investments in debt securities including changes in interest rates and the quality of credit extended. 

Quantitative Model Risk. Quantitative models used by the Fund or Index may not be effective in selecting the most favorable securities for the Fund or for inclusion in the Index and may cause the Fund to underperform other investment strategies. Flaws or errors in the quantitative model’s assumptions, design, execution, or data inputs may adversely affect Fund performance. Quantitative models may not perform as expected and may underperform in certain market environments including in stressed or volatile market conditions. There can be no assurance that the use of quantitative models will enable the Fund to achieve its objective. 

Rule 144A and Other Exempted Securities Risk. The Fund may invest in privately placed and other securities or instruments exempt from SEC registration (collectively “private placements”), subject to certain regulatory restrictions. In the U.S. market, private placements are typically sold only to qualified institutional buyers, or qualified purchasers, as applicable. An insufficient number of buyers interested in purchasing private placements at a particular time could adversely affect the marketability of such investments and the Fund might be unable to dispose of them promptly or at reasonable prices, subjecting the Fund to liquidity risk (the risk that it may not be possible for the Fund to liquidate the instrument at an advantageous time or price). The Fund’s holdings of private placements may increase the level of Fund illiquidity if eligible buyers are unable or unwilling to purchase them at a particular time. The Fund may also have to bear the expense of registering the securities for resale and the risk of substantial delays in effecting the registration. Additionally, the purchase price and subsequent valuation of private placements typically reflect a discount, which may be significant, from the market price of comparable securities for which a more liquid market exists. Issuers of Rule 144A eligible securities are required to furnish information to potential investors upon request. However, the required disclosure is much less extensive than that required of public companies and is not publicly available since the offering information is not filed with the SEC. Further, issuers of Rule 144A eligible securities can require recipients of the offering information (such as the Fund) to agree contractually to keep the information confidential, which could also adversely affect the Fund’s ability to dispose of the security. 

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Summary of the Fund (continued)

Counterparty Risk. Counterparty risk is the risk that a counterparty to a transaction in a financial instrument held by the Fund or by a special purpose or structured vehicle invested in by the Fund may become insolvent or otherwise fail to perform its obligations. As a result, the Fund may obtain no or limited recovery of its investment, and any recovery may be significantly delayed. 

Liquidity Risk. Liquidity risk is the risk associated with any event, circumstance, or characteristic of an investment or market that negatively impacts the Fund’s ability to sell, or realize the proceeds from the sale of, an investment at a desirable time or price. Liquidity risk may arise because of, for example, a lack of marketability of the investment, which means that when seeking to sell its portfolio investments, the Fund could find that selling is more difficult than anticipated, especially during times of high market volatility. Decreases in the number of financial institutions, including banks and broker-dealers, willing to make markets (match up sellers and buyers) in the Fund’s investments or decreases in their capacity or willingness to trade such investments may increase the Fund’s exposure to this risk. The debt market has experienced considerable growth, and financial institutions making markets in instruments purchased and sold by the Fund (e.g., bond dealers) have been subject to increased regulation. The impact of that growth and regulation on the ability and willingness of financial institutions to engage in trading or “making a market” in such instruments remains unsettled. Certain types of investments, such as lower-rated securities or those that are purchased and sold in over-the-counter markets, may be especially subject to liquidity risk. Securities or other assets in which the Fund invests may be traded in the over-the-counter market rather than on an exchange and therefore may be more difficult to purchase or sell at a fair price, which may have a negative impact on the Fund’s performance. Market participants attempting to sell the same or a similar instrument at the same time as the Fund could exacerbate the Fund’s exposure to liquidity risk. The Fund may have to accept a lower selling price for the holding, sell other liquid or more liquid investments that it might otherwise prefer to hold (thereby increasing the proportion of the Fund’s investments in less liquid or illiquid securities), or forego another more appealing investment opportunity. The liquidity of Fund investments may change significantly over time and certain investments that were liquid when purchased by the Fund may later become illiquid, particularly in times of overall economic distress. Changing regulatory, market or other conditions or environments (for example, the interest rate or credit environments) may also adversely affect the liquidity and the price of the Fund's investments. Judgment plays a larger role in valuing illiquid or less liquid investments as compared to valuing liquid or more liquid investments. Price volatility may be higher for illiquid or less liquid investments as a result of, for example, the relatively less frequent pricing of such securities (as compared to liquid or more liquid investments). Generally, the less liquid the market at the time the Fund sells a portfolio investment, the greater the risk of loss or decline of value to the Fund. Overall market liquidity and other factors can lead to an increase in redemptions, which may negatively impact Fund performance and NAV, including, for example, if the Fund is forced to sell investments in a down market. 

Mortgage- and Other Asset-Backed Securities Risk. The value of any mortgage-backed and other asset-backed securities including collateralized debt obligations and collateralized loan obligations, if any, held by the Fund may be affected by, among other things, changes or perceived changes in: interest rates; factors concerning the interests in and structure of the issuer or the originator of the mortgages or other assets; the creditworthiness of the entities that provide any supporting letters of credit, surety bonds or other credit enhancements; or the market's assessment of the quality of underlying assets. Payment of principal and interest on some mortgage-backed securities (but not the market value of the securities themselves) may be guaranteed by the full faith and credit of a particular U.S. Government agency, authority, enterprise or instrumentality, and some, but not all, are also insured or guaranteed by the U.S. Government. Mortgage-backed securities issued by non-governmental issuers (such as commercial banks, savings and loan institutions, private mortgage insurance companies, mortgage bankers and other secondary market issuers) may entail greater risk than obligations guaranteed by the U.S. Government. Mortgage- and other asset-backed securities are subject to liquidity risk and prepayment risk. A decline or flattening of housing values may cause delinquencies in mortgages (especially sub-prime or non-prime mortgages) underlying mortgage-backed securities and thereby adversely affect the ability of the mortgage-backed securities issuer to make principal and/or interest payments to mortgage-backed securities holders, including the Fund. Rising or high interest rates tend to extend the duration of mortgage- and other asset-backed securities, making their prices more volatile and more sensitive to changes in interest rates. 

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Summary of the Fund (continued)

LIBOR Replacement Risk. London Inter-Bank Offered Rate (LIBOR), which is used extensively in the U.S. and globally as a benchmark or reference rate for various commercial and financial contracts, among other “inter-bank offered” reference rates, is in the process of being discontinued as a global reference rate. The elimination of LIBOR may adversely affect the interest rates on, and value of, certain Fund investments that are tied to LIBOR. Such investments may include derivatives, and other assets or liabilities. On July 27, 2017, the U.K. Financial Conduct Authority (FCA) announced that it intended to stop compelling or inducing banks to submit LIBOR rates after 2021. The FCA and the ICE Benchmark Administration have since announced that a majority of U.S. dollar LIBOR settings will cease publication after June 30, 2023. A subset of non-U.S. dollar LIBOR settings are continuing to be published on a “synthetic” basis and it is possible that a subset of U.S. dollar LIBOR settings will also be published after June 30, 2023 on a “synthetic” basis. Any such publications are, or would be considered, non-representative of the underlying market. The U.S. Federal Reserve, based on the recommendations of the New York Federal Reserve’s Alternative Reference Rate Committee (comprised of major derivative market participants and their regulators), has begun publishing and promoting SOFR as the alternative reference rate to U.S. dollar LIBOR. Proposals for alternative reference rates for other currencies have also been announced or have already begun publication. Markets are slowly developing in response to these new reference rates. Uncertainty related to the liquidity impact of the change in rates, and how to appropriately adjust these rates at the time of transition, poses risks for the Fund. The effect of the discontinuation of LIBOR on the Fund will depend on, among other things, (1) existing fallback or termination provisions in individual contracts and (2) whether, how, and when industry participants develop and adopt new reference rates and fallbacks for both legacy and new instruments and contracts. The discontinuation of LIBOR could have a significant impact on the financial markets in general and may also present heightened risk to market participants, including public companies, investment advisers, investment companies, and broker-dealers. The risks associated with this discontinuation and transition will be exacerbated if the work necessary to effect an orderly transition to an alternative reference rate is not completed in a timely manner. For example, current information technology systems may be unable to accommodate new instruments and rates with features that differ from LIBOR. Accordingly, it is difficult to predict the full impact of the transition away from LIBOR on the Fund until new reference rates and fallbacks for both legacy and new products, instruments and contracts are commercially accepted and market practices become more settled. 

Frequent Trading Risk. The portfolio managers may actively and frequently trade investments in the Fund's portfolio to carry out its investment strategies . Frequent trading of investments increases the possibility that the Fund, as relevant, will realize taxable capital gains (including short-term capital gains, which are generally taxable to shareholders at higher rates than long-term capital gains for U.S. federal income tax purposes), which could reduce the Fund's after-tax return. Frequent trading can also mean higher brokerage and other transaction costs, which could reduce the Fund's return. The trading costs and tax effects associated with portfolio turnover may adversely affect the Fund’s performance. 

Leverage Risk. Leverage occurs when the Fund increases its assets available for investment using borrowings, derivatives, or similar instruments or techniques. Use of leverage can produce volatility and may exaggerate changes in the NAV of Fund shares and in the return on the Fund’s portfolio, which may increase the risk that the Fund will lose more than it has invested. The use of leverage may cause the Fund to liquidate portfolio positions when it may not be advantageous to do so to satisfy its obligations or to meet any required asset segregation or position coverage requirements. Futures contracts, options on futures contracts, forward contracts and other derivatives can allow the Fund to obtain large investment exposures in return for meeting relatively small margin requirements. As a result, investments in those transactions may be highly leveraged. If the Fund uses leverage, through the purchase of particular instruments such as derivatives, the Fund may experience capital losses that exceed the net assets of the Fund. Leverage can create an interest expense that may lower the Fund's overall returns. Leverage presents the opportunity for increased net income and capital gains, but may also exaggerate the Fund's volatility and risk of loss. There can be no guarantee that a leveraging strategy will be successful. 

Stripped Mortgage-Backed Securities Risk. Stripped mortgage-backed securities are a type of mortgage-backed security that receive differing proportions of the interest and principal payments from the underlying assets. Generally, there are two classes of stripped mortgage-backed securities: Interest Only (IO) and Principal Only (PO). IOs entitle the holder to receive distributions consisting of all or a portion of the interest on the underlying pool of 

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Summary of the Fund (continued)

mortgage loans or mortgage-backed securities. POs entitle the holder to receive distributions consisting of all or a portion of the principal of the underlying pool of mortgage loans or mortgage-backed securities. The cash flows and yields on IOs and POs are extremely sensitive to the rate of principal payments (including prepayments) on the underlying mortgage loans or mortgage-backed securities. A rapid rate of principal payments may adversely affect the yield to maturity of IOs. A slow rate of principal payments may adversely affect the yield to maturity of POs. If prepayments of principal are greater than anticipated, an investor in IOs may incur substantial losses. If prepayments of principal are slower than anticipated, the yield on a PO will be affected more severely than would be the case with a traditional mortgage-backed security. 

The Fund is subject indirectly to the following risks of Portfolio Funds seeking returns that correspond to a stated market index (the Index). 

Passive Investment Risk. The Fund is not “actively” managed and may be affected by a general decline in market segments related to its underlying index. The Fund invests in securities or instruments included in, or believed by the Portfolio Fund’s Investment Manager to be representative of, its underlying index, regardless of their investment merits. The Fund does not seek temporary defensive positions when markets decline or appear overvalued. 

Index Fund Risk. An index fund seeks to track the performance of the Index by using indexing strategies and, therefore, would not necessarily sell a security because the security’s issuer was in financial trouble or defaulted, or whose credit rating was downgraded, unless that security was removed from the Index. The decision of whether to remove a security from an index is made by an independent index provider who is not affiliated with the Fund or the Investment Manager or its affiliates. 

Index Methodology Risk. An index fund seeks performance that corresponds to the performance of the Index. There is no guarantee or assurance that the Index will achieve high, or even positive, returns. The Index may underperform more traditional indices. In turn, the Fund could lose value while other indices or measures of market performance increase in value or performance. In addition, the Fund may be subject to the risk that the index provider may not follow its stated methodology for construction of the Index or may make errors in Index computation, construction and rebalancing despite any index provider procedures designed to prevent such occurrences and despite due diligence conducted by the investment manager or the index provider. Errors may result in a negative performance impact to the Fund and its shareholders. 

Correlation/Tracking Error Risk. An index fund’s value will generally decline when the performance of the securities in the Index declines. A number of factors may affect the Fund’s ability to achieve a high degree of correlation with the Index, and there is no guarantee that the Fund will achieve a high degree of correlation. Failure to achieve such degree of correlation may prevent the Fund from achieving its investment objective. The factors that may adversely affect the Fund’s correlation with the Index include the size of the Fund’s portfolio, fees, expenses, transaction costs, income items, valuation methodology, accounting standards, the effectiveness of sampling techniques (if applicable), changes in the Index and disruptions or illiquidity in the markets for the securities in which the Fund invests. While the Fund typically attempts to track the performance of the Index by investing all, or substantially all, of its assets in the securities that make up the Index in approximately the same proportion as their weighting in the Index, at times, the Fund may not have investment exposure to all securities in the Index, or its weighting of investment exposure to securities may be different from that of the Index. In addition, the Fund may invest in securities not included in the Index. The Fund may take or refrain from taking investment positions for various reasons, such as tax efficiency purposes, or to comply with regulatory restrictions, which may negatively affect the Fund’s correlation with the Index. The Fund may also be subject to large movements of assets into and out of the Fund, potentially resulting in the Fund being over- or under-exposed to certain securities comprising the Index and may be impacted by Index reconstitutions and Index rebalancing events. Holding cash balances may detract from the Fund’s ability to track the Index. In addition, the Fund’s NAV may deviate from the Index if the Fund fair values a portfolio security at a price other than the price used by the Index for that security. The Fund also bears management and other expenses and transaction costs in trading securities, which the Index does not bear. Accordingly, the Fund’s performance will likely fail to match the performance of the Index, after taking expenses into account. Any of these factors could decrease correlation between the performance of the Fund and the Index and may hinder the Fund’s ability to meet its investment objective. It is not possible to invest directly in an index. 

24 Prospectus 2022

Columbia Thermostat Fund^SM

Summary of the Fund (continued)

The Fund is subject indirectly to the following risks of Portfolio Funds that are exchange-traded funds seeking investment results that, before fees and expenses, closely correspond to the performance of a stated index (the Index). 

Exchange-Traded Fund (ETF) Risk. ETFs are subject to, among other risks, tracking risk and passive and, in some cases, active investment risk. An ETF’s share price may not track its specified market index (if any) and may trade below its NAV. Certain ETFs use a “passive” investment strategy and do not take defensive positions in volatile or declining markets. Other ETFs are actively managed ETFs (i.e., they do not track a particular benchmark), which are subject to active management risk. An active secondary market in ETF shares may not develop or be maintained and may be halted or interrupted due to actions by its listing exchange, unusual market conditions or other reasons. There can be no assurance that an ETF’s shares will continue to be listed on an active exchange. In addition, shareholders bear expenses incurred through ownership of the ETF. There is a risk that ETFs may terminate due to extraordinary events. For example, any of the service providers to ETFs, such as the trustee or sponsor, may close or otherwise fail to perform their obligations to the ETF, and the ETF may not be able to find a substitute service provider. Also, certain ETFs may be dependent upon licenses to use various indexes as a basis for determining their compositions and/or otherwise to use certain trade names. If these licenses are terminated, the ETFs may also terminate. In addition, an ETF may terminate if its net assets fall below a certain amount. 

Secondary Market Trading Risk. Investors buying or selling Fund shares will pay brokerage commissions or other charges imposed by brokers as determined by that broker. Brokerage commissions are often a fixed amount and may be a significant proportional cost for investors seeking to buy or sell relatively small amounts of shares. In addition, secondary market investors will also incur the cost of the difference between the price that an investor is willing to pay for Fund shares (the bid price) and the price at which an investor is willing to sell Fund shares (the ask price). This difference in bid and ask prices is often referred to as the “spread” or “bid/ask spread.” The bid/ask spread varies over time for Fund shares based on trading volume and market liquidity, and is generally lower if the Fund’s shares have more trading volume and market liquidity and higher if the Fund’s shares have little trading volume and market liquidity. Further, increased market volatility may cause increased bid/ask spreads. 

Market Price Relative to NAV Risk. Shares of the Fund may trade at prices that vary from Fund NAV. Shares of the Fund are listed for trading on the Exchange (as defined in the Portfolio Fund's prospectus) and are bought and sold in the secondary market at market prices that may differ, in some cases significantly, from their NAV. The NAV of the Fund will generally fluctuate with changes in the market value of the Fund’s holdings. The market prices of shares, however, will generally fluctuate in response to changes in NAV, as well as the relative supply of, and demand for, Fund shares on the Exchange. The Investment Manager cannot predict whether Fund shares will trade below, at or above their NAV. Price differences may result because of, among other factors, supply and demand forces in the secondary trading market for Fund shares. It is expected that these forces generally will be closely related to, but not identical to, the same forces influencing the prices of the Fund’s holdings. In this regard, if a shareholder purchases Fund shares at a time when the market price is at a premium to the NAV or sells shares at a time when the market price is at a discount to the NAV, the shareholder may sustain losses. Different investment strategies or techniques, including those intended to be defensive in nature, including, as examples, stop loss orders to sell an ETF’s shares in the secondary market during negative market events or conditions, such as a “flash crash” or other market disruptions, may not work as intended and may produce significant losses to investors. Investors should consult their financial intermediary prior to using any such investment strategies or techniques, or before investing in the Fund. 

Authorized Participant Concentration Risk. Only an Authorized Participant (as defined in the Portfolio Fund's prospectus) may engage in creation or redemption transactions directly with the Fund. The Fund has a limited number of institutions that may act as Authorized Participants, none of which are or will be obligated to engage in creation or redemption transactions. To the extent that these institutions exit the business or are unable or unwilling to proceed with creation and/or redemption orders with respect to the Fund and no other Authorized Participant is able or willing to step forward to create or redeem Creation Units (as defined in the Portfolio Fund's prospectus), Fund shares may trade at a discount to NAV and possibly face trading halts and/or delisting from the Exchange. This risk is heightened in times of market stress, including at both the Fund share level and at the Fund holdings level. 

Prospectus 2022 25

Columbia Thermostat Fund^SM

Summary of the Fund (continued)

Fund Shares Liquidity Risk. Although the Fund’s shares are listed on the Exchange, there can be no assurance that an active, liquid or otherwise orderly trading market for shares will be established or maintained by market makers or Authorized Participants, particularly in times of stressed market conditions. There is no guarantee that the Fund will be able to attract market makers and Authorized Participants. There is no obligation for market makers to make a market in the Fund’s shares or for Authorized Participants to submit purchase or redemption orders for creation units. Accordingly, if such parties determine not to perform their respective functions, this could, such as during times of market stress, in turn, lead to variances between the market price of the Fund’s shares and the underlying value of those shares and bid/ask spreads could widen. Trading in Fund shares on the Exchange also may be disrupted or even halted due to market conditions or for reasons that, in the view of the Exchange, make trading in Fund shares inadvisable. In addition, trading in Fund shares on the Exchange may be subject to trading halts caused by extraordinary market volatility pursuant to the Exchange “circuit breaker” rules. There also can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund’s shares will continue to be met or will remain unchanged. 

Early/Late Close/Trading Halt Risk.  An exchange or market may close early, close late or issue trading halts on specific securities, or the ability to buy or sell certain securities may be restricted, which may result in the Fund being unable to buy or sell these securities. In these circumstances, the Fund may be unable to rebalance its portfolio, may be unable to accurately price its investments, may incur substantial trading losses and/or may be prevented from sufficiently tracking the performance of the Index. 

Concentration Risk. The Fund will concentrate its investments in issuers conducting business in a related group of industries within a sector(s) to approximately the same extent as the Index. Issuers in the same industry or group of industries or sector may be similarly affected by economic, regulatory, political or market events or conditions, which may make the Fund more vulnerable to unfavorable developments in that sector than funds that invest more broadly. Generally, the more broadly a fund diversifies its investments, the more it spreads risk and potentially reduces the risks of loss and volatility. 

Performance Information

The following bar chart and table show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. The bar chart shows how the Fund’s Class Inst share performance has varied for each full calendar year shown. The table below the bar chart compares the Fund’s returns for the periods shown with those of two broad-based indexes: the S&P 500^® Index, the Fund’s primary benchmark for equity securities, and the Bloomberg U.S. Aggregate Bond Index, the Fund’s primary benchmark for debt securities. The table below also compares the Fund's returns with a secondary, custom index, the Blended Benchmark. The S&P 500^® Index tracks the performance of 500 widely held, large-capitalization U.S. stocks. The Bloomberg U.S. Aggregate Bond Index is a market value-weighted index that tracks the daily price, coupon, pay-downs, and total return performance of fixed-rate, publicly placed, dollar-denominated, and non-convertible investment grade debt issues with at least $250 million par amount outstanding and with at least one year to final maturity. The Blended Benchmark was established by the Investment Manager to show how the Fund’s performance compares to an equally weighted custom composite of the Fund’s primary equity and primary debt benchmarks, the S&P 500^® Index and the Bloomberg U.S. Aggregate Bond Index, respectively. The percentage of the Fund’s assets allocated to underlying stock and bond Portfolio Funds will vary, and accordingly the composition of the Fund’s portfolio will not always reflect the composition of the Blended Benchmark. 

The performance of one or more share classes shown in the Average Annual Total Returns table below includes the Fund’s Class Inst share returns (adjusted to reflect the higher class-related operating expenses of such classes, where applicable) for periods prior to the indicated inception date of such share classes. Except for differences in fees and expenses, all share classes of the Fund would have substantially similar annual returns because all share classes of the Fund invest in the same portfolio of securities. 

The after-tax returns shown in the Average Annual Total Returns table below are calculated using the highest historical individual U.S. federal marginal income tax rates in effect during the period indicated in the table and do not reflect the impact of state, local or foreign taxes. Your actual after-tax returns will depend on your personal tax 

26 Prospectus 2022

Columbia Thermostat Fund^SM

Summary of the Fund (continued)

situation and may differ from those shown in the table. In addition, the after-tax returns shown in the table do not apply to shares held in tax-advantaged accounts such as 401(k) plans or Individual Retirement Accounts (IRAs). The after-tax returns are shown only for Class Inst shares and will vary for other share classes. 

The Fund’s performance prior to May 2018 reflects returns achieved following a principal investment strategy with a single form of asset allocation table. While the Fund now follows a principal investment strategy with two potential forms of asset allocation tables, as described above in the Principal Investment Strategies section, the form of the Fund’s currently effective asset allocation table was in place from the Fund’s inception in 2002 through April 30, 2020. The Fund's performance prior to May 1, 2020 and after April 30, 2021 reflects the current form of allocation table. The Fund's performance from May 1, 2020 through April 30, 2021 reflects a different form of asset allocation table. 

The Fund’s past performance (before and after taxes) is no guarantee of how the Fund will perform in the future. Updated performance information can be obtained by calling toll-free 800.345.6611 or visiting columbiathreadneedleus.com. 

Year by Year Total Return (%) as of December 31 Each Year*	Best and Worst Quarterly Returns During the Period Shown in the Bar Chart
	Best	2nd Quarter 2020	13.30%
	Worst	3rd Quarter 2015	-2.27%

* Year to Date return as of March 31, 2022: -5.87%

Prospectus 2022 27

Columbia Thermostat Fund^SM

Summary of the Fund (continued)

 Average Annual Total Returns After Applicable Sales Charges (for periods ended December 31, 2021)

	Share Class Inception Date	1 Year	5 Years	10 Years
Class Inst	09/25/2002
returns before taxes		6.42%	10.91%	8.75%
returns after taxes on distributions		2.26%	8.36%	6.82%
returns after taxes on distributions and sale of Fund shares		5.30%	7.76%	6.34%
Class A returns before taxes	03/03/2003	0.04%	9.33%	7.83%
Class Adv returns before taxes	11/08/2012	6.43%	10.91%	8.74%
Class C returns before taxes	03/03/2003	4.47%	9.81%	7.66%
Class Inst2 returns before taxes	11/08/2012	6.53%	10.95%	8.78%
Class Inst3 returns before taxes	11/08/2012	6.52%	11.00%	8.82%
Blended Benchmark (Secondary Benchmark; an equally weighted custom composite of the Fund's primary benchmarks for equity and debt securities, established by the Investment Manager; reflects no deductions for fees, expenses or taxes)		12.80%	11.12%	9.78%
S&P 500® Index (Primary Equity Benchmark; reflects no deductions for fees, expenses or taxes)		28.71%	18.47%	16.55%
Bloomberg U.S. Aggregate Bond Index (Primary Debt Benchmark; reflects no deductions for fees, expenses or taxes)		-1.54%	3.57%	2.90%

Fund Management

Investment Manager: Columbia Wanger Asset Management, LLC

Portfolio Management	Title	Role with Fund	Service with the Fund Since
Anwiti Bahuguna, Ph.D.	Senior Portfolio Manager and Head of Multi Asset Strategy of Columbia Management and Assistant Vice President of the Investment Manager	Lead Portfolio Manager or Co-Portfolio Manager since 2018	2018
Alex M. Rivas	Portfolio Manager of Columbia Management and Assistant Vice President of the Investment Manager	Portfolio Manager since May 2022	2018

28 Prospectus 2022

Columbia Thermostat Fund^SM

Summary of the Fund (continued)

Purchase and Sale of Fund Shares

You may purchase or redeem shares of the Fund on any business day by contacting the Fund in the ways described below:

Online	Regular Mail	Express Mail	By Telephone
columbiathreadneedleus.com/investor/	Columbia Management Investment Services Corp. P.O. Box 219104 Kansas City, MO 64121-9104	Columbia Management Investment Services Corp. c/o DST Asset Manager Solutions, Inc. 430 W 7th Street, Suite 219104 Kansas City, MO 64105-1407	800.422.3737

You may purchase shares and receive redemption proceeds by electronic funds transfer, by check or by wire. If you maintain your account with a broker-dealer or other financial intermediary, you must contact that financial intermediary to buy, sell or exchange shares of the Fund through your account with the intermediary.

The minimum initial investment amounts for the share classes offered by the Fund are shown below:

Minimum Initial Investment

Class	Category of eligible account	For accounts other than Systematic Investment Plan accounts (as described in the Fund’s Prospectus)	For Systematic Investment Plan accounts
Classes A & C	All accounts other than IRAs	$2,000	$100
	IRAs	$1,000	$100
Classes Adv & Inst	All eligible accounts	$0, $1,000 or $2,000 depending upon the category of eligible investor	$100
Class Inst2	All eligible accounts	None	N/A
Class Inst3	All eligible accounts	$0, $1,000, $2,000 or $1 million depending upon the category of eligible investor	$100 (for certain eligible investors)

More information about these minimums can be found in the Buying, Selling and Exchanging Shares - Buying Shares section of the prospectus. There is no minimum additional investment for any share class.

Tax Information

The Fund normally distributes net investment income and net realized capital gains, if any, to shareholders. These distributions are generally taxable to you as ordinary income or capital gains, unless you are investing through a tax-advantaged account, such as a 401(k) plan or an IRA. The use of a fund-of-funds structure could affect the timing, amount and character of distributions to you and therefore may increase the amount of taxes payable by you. If you are investing through a tax-advantaged account, you may be taxed upon withdrawals from that account.

Payments to Broker-Dealers and Other Financial Intermediaries

If you purchase the Fund through a broker-dealer or other financial intermediary (such as a bank), the Fund and its related companies – including the Investment Manager, the Distributor and Columbia Management Investment Services Corp. (the Transfer Agent) – may pay the intermediary for the sale of Fund shares and related services. These payments may create a conflict of interest by influencing the broker-dealer or other intermediary and your financial advisor to recommend the Fund over another investment. These potential conflicts of interest may be heightened with respect to broker-dealers owned by Ameriprise Financial, Inc. (Ameriprise Financial) and/or its affiliates. Ask your financial advisor or visit your financial intermediary's website for more information.

Prospectus 2022 29

Columbia Thermostat Fund^SM

Portfolio Funds Summary

The following provides a brief overview of the investment objectives and principal investments of the Portfolio Funds in which the Fund invests. The Fund’s NAV is calculated based on the NAVs of the Portfolio Funds.

You'll find more detailed information about each Portfolio Fund’s investment strategies and risks in its prospectus and SAI. The Portfolio Funds’ prospectuses also discuss the circumstances under which the Portfolio Funds use fair value pricing and the effects thereof. Refer to columbiathreadneedle.com/us or contact your financial advisor for details.

Columbia Acorn^® Fund

■ The fund seeks long-term capital appreciation.

■ Under normal circumstances, the fund invests a majority of its net assets in the common stock of small- and midsized companies with market capitalizations generally in the range of market capitalizations in the Russell 2500 Growth Index, the fund’s benchmark. The market capitalization range and composition of the companies in the index are subject to change. As such, the size of the companies in which the Fund invests may change. As long as an investment continues to meet the fund’s other investment criteria, the fund may continue to hold and make new investments in a security even if the company’s market capitalization grows beyond the market capitalization of the largest company within the index or falls below the market capitalization of the smallest company within the index.

■ The fund invests the majority of its assets in U.S. companies, but also may invest up to 33% of its total assets in foreign companies in developed markets (for example, Japan, Canada and the United Kingdom) and in emerging markets (for example, China, India and Brazil).

■ The principal risks of the fund include Active Management Risk, Small- and Mid-Cap Company Securities Risk, Market Risk, Issuer Risk, Growth Securities Risk, Liquidity and Trading Volume Risk, Sector Risk (including the Health Care sector and Information Technology sector), Foreign Securities Risk and Foreign Currency Risk.

Columbia Contrarian Core Fund

■ The fund seeks total return, consisting of long-term capital appreciation and current income.

■ Under normal circumstances, the fund invests at least 80% of its net assets (including the amount of any borrowings for investment purposes) in common stocks, and at least 80% of its net assets in equity securities of U.S. companies that have large market capitalizations (generally over $2 billion) that the fund’s investment adviser believes are undervalued and have the potential for long-term growth and current income.

■ The fund may invest up to 20% of its net assets in foreign securities directly or indirectly through depositary receipts.

■ The fund may at times emphasize one or more sectors in selecting its investments, including the information technology sector.

■ The principal risks of the fund include Active Management Risk, Changing Distribution Level Risk, Depositary Receipts Risk, Foreign Securities Risk, Growth Securities Risk, Issuer Risk (including Large-Cap Stock Risk), Market Risk, Sector Risk (including Information Technology sector), and Value Securities Risk.

Columbia Corporate Income Fund

■ The fund seeks total return, consisting primarily of current income and secondarily of capital appreciation.

■ Under normal circumstances, the fund invests at least 80% of its net assets (including the amount of any borrowings for investment purposes) in debt securities issued by corporate and other non-governmental issuers, including dollar-denominated debt securities issued by foreign companies. The fund also invests at least 60% of total assets in securities that, at the time of purchase, are investment grade securities or in unrated securities determined to be of comparable quality. The fund may invest up to 25% of its total assets in debt instruments that, at the time of purchase, are rated below investment grade or are unrated but determined to be of comparable quality (commonly referred to as “high-yield” investments or “junk” bonds). Under normal circumstances, the fund’s average effective duration will be between three and ten years.

■ The fund may purchase or sell securities on a when-issued, delayed delivery or forward commitment basis.

30 Prospectus 2022

Columbia Thermostat Fund^SM

Portfolio Funds Summary (continued)

■ The fund may invest in privately placed and other securities or instruments that are purchased and sold pursuant to Rule 144A or other exemptions under the Securities Act of 1933, as amended, subject to liquidity determinations and certain regulatory restrictions.

■ The fund may invest in U.S. Government obligations, asset-backed securities and mortgage-backed securities.

■ The principal risks of the fund include Active Management Risk, Changing Distribution Level Risk, Counterparty Risk, Credit Risk, Foreign Securities Risk, High Yield Investments Risk, Interest Rate Risk, Issuer Risk, Liquidity Risk, Market Risk, Mortgage- and Other Asset-Backed Securities Risk, Prepayment and Extension Risk, Reinvestment Risk, Rule 144A and Other Exempted Securities Risk, and U.S. Government Obligations Risk.

Columbia Emerging Markets Fund

■ Under normal circumstances, the fund invests at least 80% of its net assets (including the amount of any borrowings for investment purposes) in equity securities (including, but not limited to, common stocks, preferred stocks and securities convertible into common or preferred stocks) of companies located in emerging market countries. The fund may also gain exposure to such companies through investment in depositary receipts. The Fund may seek investment exposure to Chinese companies operating in certain sectors using a structure known as a variable interest entity (a VIE), rather than an equity ownership in the Chinese company. Emerging market countries include those countries whose economies are considered to be developing or emerging from underdevelopment.

■ The fund may invest in a variety of countries, industries and sectors and does not attempt to invest a specific percentage of its assets in any given country, industry or sector. However, the fund has invested substantially in the consumer discretionary, financial services and information technology sectors and may continue to invest substantially in these or other sectors in the future. From time to time, the fund may focus its investments in certain countries or geographic areas, including the Asia/Pacific region.

■ The fund may invest in companies that have market capitalizations of any size.

■ The fund may invest in special situations, such as companies involved in initial public offerings, tender offers, mergers and other corporate restructurings, and in companies involved in management changes or companies developing new technologies.

■ The fund may invest in securities that its investment adviser believes are undervalued, represent growth opportunities, or both.

■ The principal risks of the fund include Active Management Risk, Convertible Securities Risk, Depositary Receipts Risk, Emerging Market Securities Risk, Foreign Securities Risk, Geographic Focus Risk (including risk of investing in the Asia Pacific region and Greater China), Growth Securities Risk, Issuer Risk (including Small-Cap, Mid-Cap and Large-Cap Stock Risks), Liquidity Risk, Market Risk, Preferred Stock Risk, Sector Risk (including the Consumer Discretionary sector, Financial Services sector and Information Technology sector), Special Situations Risk, and Value Securities Risk.

Columbia Diversified Fixed Income Allocation ETF

■ The fund seeks investment results that, before fees and expenses, closely correspond to the performance of the Beta Advantage^® Multi-Sector Bond Index.

■ The fund is an exchange-traded fund that seeks to track the performance of the Beta Advantage^® Multi-Sector Bond Index. The fund invests at least 80% of its assets in securities within the Beta Advantage^® Multi-Sector Bond Index or in securities, such as depositary receipts and “to-be-announced” (TBA) securities, that the fund’s investment adviser determines have economic characteristics that are substantially the same as the economic characteristics of the securities within the Beta Advantage^® Multi-Sector Bond Index. For purposes of this policy, the fund invests at least 80% of its net assets (plus borrowings for investment purposes) in fixed income (or debt) securities. The fund may invest in cash, cash equivalents and money market instruments, such as repurchase agreements and money market funds (including money market funds advised by affiliates of the Investment Manager), that the fund’s investment adviser believes will help the fund track the performance of the Beta Advantage^® Multi-Sector Bond Index.

Prospectus 2022 31

Columbia Thermostat Fund^SM

Portfolio Funds Summary (continued)

■ The Beta Advantage^® Multi-Sector Bond Index is owned and calculated by Bloomberg Index Services Limited (Bloomberg), which is not affiliated with the fund or the Investment Manager and its affiliates. The Beta Advantage^® Multi-Sector Bond Index was developed by Columbia Management working with Bloomberg.

■ The Beta Advantage^® Multi-Sector Bond Index, and therefore the fund, will have exposure to the following six segments of the debt market in the Beta Advantage^® Multi-Sector Bond Index, each focused on yield, quality, and liquidity of the particular segment. The Beta Advantage^® Multi-Sector Bond Index, and therefore the fund, will have exposure to the following six segments of the debt market (% amount noted is the index’s allocation to the particular segment at index rebalancing and reconstituted as described in the fund’s prospectus): U.S. Treasury securities (10%); global ex-U.S. Treasury securities (10%); U.S. agency mortgage-backed securities (15%); U.S. corporate investment grade bonds (15%); U.S. corporate high yield bonds (30%); and emerging markets sovereign and quasi-sovereign debt (20%). The Beta Advantage^® Multi-Sector Bond Index’s allocation to each of the six segments of the debt market, represented by the six sub-index models, is fixed as of each rebalancing and reconstitution, but may vary due to the performance of each segment between these events. The number of securities in each of the six sub-index models and the Beta Advantage^® Multi-Sector Bond Index as a whole are subject to change. Each segment sub-index model is market value-weighted except for the global ex-U.S. Treasury securities segment sub-index model, which is equal-weighted. Please see the fund’s prospectus for additional information on the Beta Advantage^® Multi-Sector Bond Index’s six sub-index models and generation of the component securities of the Beta Advantage^® Multi-Sector Bond Index.

■ The Beta Advantage^® Multi-Sector Bond Index is reconstituted and rebalanced monthly and will typically experience portfolio turnover in connection with the reconstituting and rebalancing.

■ The fund may invest in privately placed and other securities or instruments that are purchased and sold pursuant to Rule 144A or other exemptions under the Securities Act of 1933, as amended, subject to certain regulatory restrictions.

■ The fund’s investment adviser expects to utilize a “representative sampling” strategy whereby the fund invests in only some of the component securities of the Beta Advantage^® Multi-Sector Bond Index that, collectively, are believed by the fund’s investment adviser to generally reflect the same risk and return characteristics of the Beta Advantage^® Multi-Sector Bond Index. As such, the Fund may not track the Beta Advantage^® Multi-Sector Bond Index with the same degree of accuracy as would a fund replicating the entire Beta Advantage^® Multi-Sector Bond Index.

■ The Fund expects to typically hold 500 to 800 holdings, which is a subset of the total number of holdings in the Beta Advantage^® Multi-Sector Bond Index. The Fund may hold less than or more than the typical number of holdings with the fund portfolio management team applying investment experience and insight with the goal of seeking investment results that closely correspond to the performance of the Beta Advantage^® Multi-Sector Bond Index.

■ The fund may sell securities or other holdings that are represented in the Beta Advantage^® Multi-Sector Bond Index or purchase securities or make other investments that are not yet represented in the Beta Advantage^® Multi-Sector Bond in anticipation of their removal from or addition to the index by Bloomberg.

■ The fund’s assets are not invested based on its investment adviser’s view of the investment merits of a particular security or company, neither does the fund’s investment adviser conduct fundamental investment research or analysis, nor seek to forecast or otherwise consider market movements, conditions or trends in managing the fund’s assets. The fund pursues its investment objective of correlating performance with the Beta Advantage^® Multi-Sector Bond Index regardless of market conditions and does not take defensive positions.

■ To the extent the Beta Advantage^® Multi-Sector Bond Index is concentrated in a particular segment, sector or industry, the fund will be concentrated in that segment, sector or industry.

■ The principal risks of the fund include Authorized Participant Concentration Risk, Changing Distribution Level Risk, Concentration Risk, Correlation/Tracking Error Risk, Counterparty Risk, Credit Risk, Depositary Receipts Risk, Early Close/Late Close/Trading Halt Risk, Emerging Market Securities Risk, Foreign Currency Risk, Foreign Securities Risk, Forward Commitments on Mortgage-Backed Securities (including Dollar Rolls) Risk, Frequent

32 Prospectus 2022

Columbia Thermostat Fund^SM

Portfolio Funds Summary (continued)

Trading Risk. Fund Shares Liquidity Risk, High-Yield Investments Risk, Index Methodology Risk, Interest Rate Risk, Issuer Risk, Liquidity Risk, Market Price Relative to NAV Risk, Market Risk, Mortgage Backed Securities Risk, Passive Investment Risk, Portfolio Turnover Risk, Prepayment and Extension Risk, Reinvestment Risk, Rule 144A and Other Exempted Securities Risk, Secondary Market Trading Risk, Sector Risk, Sovereign Debt Risk, U.S. Government Obligations Risk, and Valuation Risk.

Columbia Large Cap Enhanced Core Fund

■ The fund seeks total return before fees and expenses that exceeds the total return of the S&P 500^® Index.

■ Under normal circumstances, the fund invests at least 80% of its net assets (including the amount of any borrowings for investment purposes) in common stocks that comprise the S&P 500^® Index, convertible securities that are convertible into stocks included in the S&P 500^® Index, and derivatives whose returns are closely equivalent to the returns of the S&P 500^® Index or its components.

■ The fund generally holds fewer stocks than the S&P 500^® Index and may hold securities that are not in the S&P 500^® Index.

■ The fund’s investment adviser attempts to maintain a portfolio that generally matches the risk characteristics of the S&P 500^® Index, but it will vary the number and percentages of the fund’s holdings in attempting to provide higher returns than the S&P 500^® Index and to reduce the potential of underperforming the S&P 500^® Index over time.

■ The fund may from time to time emphasize one or more economic sectors in selecting its investments, including the information technology sector.

■ The fund’s portfolio managers use quantitative analysis to evaluate the relative attractiveness of potential investments.

■ The fund may invest in derivatives, such as futures (including equity futures and index futures), for cash equitization and investment flexibility.

■ The principal risks of the fund include Active Management Risk, Convertible Securities Risk, Counterparty Risk, Derivatives Risk, Derivatives Risk – Futures Contracts Risk, Issuer Risk (including Large-Cap Stock Risk), Market Risk, Quantitative Model Risk, and Sector Risk (including the Information Technology sector).

Columbia Large Cap Index Fund

■ The fund seeks total return before fees and expenses that corresponds to the total return of the S&P 500^® Index.

■ Under normal circumstances, the fund invests at least 80% of its net assets (including the amount of any borrowings for investment purposes) in common stocks that comprise the S&P 500^® Index.

■ The fund’s investment adviser attempts to allocate the fund’s assets among common stocks in approximately the same weightings as the S&P 500^® Index. This is referred to as a passive or indexing approach to investing. The fund’s portfolio will typically emphasize those economic sectors emphasized by the S&P 500^® Index, such as the information technology sector.

■ The fund may invest in derivatives, such as futures (including equity index futures), for cash equitization purposes.

■ The fund attempts to achieve at least a 95% correlation between the performance of the S&P 500^® Index and the fund’s investment results, before fees and expenses.

■ The fund may buy shares of Ameriprise Financial, Inc., an affiliate of the Investment Manager, which is currently included in the S&P 500^® Index, subject to certain restrictions.

■ The principal risks of the fund include Correlation/Tracking Error Risk, Derivatives Risk, Derivatives Risk – Futures Contracts Risk, Issuer Risk (including Large-Cap Stock Risk), Market Risk, Passive Investment Risk, and Sector Risk (including the Information Technology sector).

Columbia Quality Income Fund

Prospectus 2022 33

Columbia Thermostat Fund^SM

Portfolio Funds Summary (continued)

■ The fund seeks to provide shareholders with current income as its primary objective and, as its secondary objective, preservation of capital.

■ Under normal market conditions, at least 80% of the fund’s net assets (including the amount of any borrowings for investment purposes) are invested in mortgage-related securities, which include those that are either issued or guaranteed as to principal and interest by the U.S. Government, its agencies, authorities or instrumentalities (U.S. Government Securities), those issued by non-U.S. governments, as well as residential and commercial mortgage-backed securities issued by non-governmental entities. Mortgage-related securities that either are issued or guaranteed as to principal and interest by the U.S. Government, its agencies, authorities or instrumentalities include Government National Mortgage Association (GNMA or Ginnie Mae) mortgage-backed bonds, which are backed by the full faith and credit of the U.S. Government; and Federal National Mortgage Association (FNMA or Fannie Mae) and Federal Home Loan Mortgage Corporation (FHLMC or Freddie Mac) mortgage backed bonds. FNMA and FHLMC are chartered or sponsored by Acts of Congress; however, their securities are neither issued nor guaranteed by the U.S. Treasury or backed by the full faith and credit of the U.S. Government.

■ The fund may invest in stripped mortgage-backed securities such as interest-only (IO) and principal-only (PO) securities.

■ Under normal circumstances, the Fund invests at least 60% of its net assets in mortgage-related securities that are U.S. Government Securities and at least 80% of its net assets in securities rated investment grade by a nationally recognized statistical rating organization or, if unrated, determined to be of comparable quality. The Fund may invest up to 20% of its net assets in debt instruments that, at the time of purchase, are rated below investment grade or are unrated but determined to be of comparable quality (commonly referred to as "high-yield” investments or “junk” bonds).

■ The fund may invest in debt instruments of any maturity and does not seek to maintain a particular dollar-weighted average maturity.

■ The fund may invest in privately placed securities and other securities or instruments that are purchased and sold pursuant to Rule 144A or other exemptions under the Securities Act of 1933 subject to liquidity determinations and certain regulatory restrictions.

■ The fund may invest in derivatives, such as futures (including interest rate futures) to manage interest rate exposure, swaps (including interest rate swaps and total return swaps) to manage credit and interest rate exposure and options on swaps (commonly known as swaptions) to manage interest rate exposure. The fund’s use of derivatives may result in leverage (market exposure in excess of the fund’s assets). The fund may hold a significant amount of cash, money market instruments (which may include investments in one or more affiliated or unaffiliated money market funds or similar vehicles), other high-quality, short-term investments, or other liquid assets to meet its segregation obligations as a result of its investments in derivatives.

■ The fund may purchase or sell securities on a when-issued, delayed delivery or forward commitment basis. Such securities may include mortgage-backed securities acquired or sold in the “to be announced” (TBA) market and those in a dollar roll transaction.

■ The fund’s investment strategy may involve the frequent trading of portfolio securities.

■ The principal risks of the fund include Active Management Risk, Changing Distribution Level Risk, Counterparty Risk, Credit Risk, Derivatives Risk, Derivatives Risk – Futures Contracts Risk, Derivatives Risk – Options Risk, Derivatives Risk – Swaps Risk, Derivatives Risk – Swaptions Risk, Forward Commitments on Mortgage-Backed Securities (including Dollar Rolls) Risk, Frequent Trading Risk, High-Yield Investments Risk, Interest Rate Risk, Leverage Risk, Liquidity Risk, Market Risk, Mortgage- and Other Asset-Backed Securities Risk, Prepayment and Extension Risk, Reinvestment Risk, Rule 144A and Other Exempted Securities Risk, Sovereign Debt Risk, Stripped Mortgage-Backed Securities Risk, and U.S. Government Obligations Risk.

Columbia Research Enhanced Core ETF

■ The fund seeks investment results that, before fees and expenses, closely correspond to the performance of the Beta Advantage^® Research Enhanced U.S. Equity Index.

34 Prospectus 2022

Columbia Thermostat Fund^SM

Portfolio Funds Summary (continued)

■ The fund is an exchange-traded fund that seeks to replicate the performance of the Beta Advantage^® Research Enhanced U.S. Equity Index. The fund invests at least 80% of its assets in the securities of the Beta Advantage^® Research Enhanced U.S. Equity Index. The Beta Advantage^® Research Enhanced U.S. Equity Index reflects a rules-based strategic beta approach to investing in the companies that comprise the Russell 1000^® Index, designed to achieve stronger total return when compared to the Russell 1000^® Index, which is a broad measure of the performance of U.S. large- and mid-cap growth and value companies. The Beta Advantage^® Research Enhanced U.S. Equity Index, like the Russell 1000^® Index, and therefore the Fund, typically holds only common stocks.

■ The Beta Advantage^® Research Enhanced U.S. Equity Index was developed and is sponsored and administered by the fund’s investment adviser, Columbia Management. The Index is calculated and maintained by FTSE Russell.

■ The Beta Advantage^® Research Enhanced U.S. Equity Index is comprised of a subset of the companies within the Russell 1000^® Index. With a starting point of the Russell 1000^® Index, the Beta Advantage^® Research Enhanced U.S. Equity Index was designed to reflect the performance of U.S. large- and mid-cap growth and value companies through the application of a rules-based methodology, which typically results in approximately 325-400 holdings, but this range can fluctuate because the Beta Advantage^® Research Enhanced U.S. Equity Index has no constraints on number of holdings.

■ The Beta Advantage^® Research Enhanced U.S. Equity Index methodology applies the results of Columbia Management’s proprietary quantitative investment models to rate each company within the Russell 1000^® Index on a 1- through 5- basis, where “1” is the strongest rating and “5” is the weakest rating, based on three main company factor composites: quality (such as earnings quality), value (such as cash flow yield), and catalyst (such as price momentum). A company’s rating is based on the relative ranking of its overall score from a multifactor model within its modeling sector. The distribution of the ratings within a given sector generally breaks down as follows: 1 – top 15% of companies; 2 – next 20% of companies; 3 – next 30% of companies; 4 – next 20% of companies; and 5 – bottom 15% of companies. The Beta Advantage^® Research Enhanced U.S. Equity Index is then systematically constructed to: exclude all companies rated a “4” or “5”; include all companies rated a “1” or a “2” in each sector as classified by the Global Industry Classification System (GICS); and include all GICS-classified Biotechnology companies, which are not rated. If, however unlikely, all companies in a GICS sector receive the same overall score from the multifactor model (and thus no ranking is possible), then all companies in such GICS sector are assigned a rating of “3” (neutral) and all such companies are included in the Beta Advantage^® Research Enhanced U.S. Equity Index. The resulting companies are then weighted in the Beta Advantage^® Research Enhanced U.S. Equity Index based on each company’s market capitalization in the Russell 1000^® Index, with such weightings further adjusted pro rata to align the total weight of each sector in the Beta Advantage^® Research Enhanced U.S. Equity Index, as well as the total weight of the Biotechnology companies in the Beta Advantage^® Research Enhanced U.S. Equity Index, to the Russell 1000^® Index’s sector weights and Biotechnology industry weight, respectively, as classified by GICS. The number of securities in each sector and the Beta Advantage^® Research Enhanced U.S. Equity Index as a whole may change over time. The Beta Advantage^® Research Enhanced U.S. Equity Index is reconstituted and rebalanced semi-annually in June and December.

■ The fund uses a replication strategy to track the performance of the Beta Advantage^® Research Enhanced U.S. Equity Index, whereby the fund invests in or has investment exposure to substantially all the component securities of the Beta Advantage^® Research Enhanced U.S. Equity Index in approximately the same proportions as in the Beta Advantage^® Research Enhanced U.S. Equity Index. However, under various circumstances, including circumstances under which it may not be possible or practicable to purchase all of the securities in the index, or in the same weightings, the fund may purchase or have investment exposure to a sample (large or small quantity) of the securities in the index in proportions expected to replicate generally the performance of the index as a whole. There may also be instances in which the fund may overweight (or underweight) a holding in the Beta Advantage^® Research Enhanced U.S. Equity Index, purchase (or sell) instruments not in the index as a substitute for one or more securities in the index or utilize various combinations of other available investment techniques in seeking to replicate the performance of the index.

Prospectus 2022 35

Columbia Thermostat Fund^SM

Portfolio Funds Summary (continued)

■ The fund may sell securities or other holdings that are represented in the Beta Advantage^® Research Enhanced U.S. Equity Index or purchase securities or make other investments that are not yet represented in the index in anticipation of their removal from or addition to the index.

■ Columbia Management does not provide day-to-day management of the fund’s assets based on its view of the investment merits of a security or company, nor does it conduct fundamental investment research or analysis, or seek to forecast or otherwise consider market movements, conditions or trends in the day-to-day management of the fund’s assets. The fund pursues its investment objective of correlating performance with the Beta Advantage^® Research Enhanced U.S. Equity Index regardless of market conditions and does not take defensive positions.

■ The methodology applied to select holdings in the Beta Advantage^® Research Enhanced U.S. Equity Index and weightings does not set limits on sector or industry exposures. To the extent the Beta Advantage^® Research Enhanced U.S. Equity Index is concentrated in a sector or industry, the fund will necessarily be concentrated in that sector or industry.

■ The fund may invest up to 20% of its assets in other securities or instruments not included within the Index that Columbia Management believes will help the fund track the Beta Advantage^® Research Enhanced U.S. Equity Index.

■ The principal risks of the fund include Authorized Participant Concentration Risk, Concentration Risk, Correlation/Tracking Error Risk, Early Close/Late Close/Trading Halt Risk, Fund Shares Liquidity Risk, Growth Securities Risk, Index Methodology Risk, Issuer Risk (including Mid-Cap Stock Risk and Large-Cap Stock Risk), Market Price Relative to NAV Risk, Market Risk, Passive Investment Risk, Quantitative Model Risk, Secondary Market Trading Risk, Sector Risk (including the Information Technology sector), and Value Securities Risk.

Columbia Select Mid Cap Value Fund

■ The fund seeks long-term capital appreciation.

■ Under normal circumstances, the fund invests at least 80% of its net assets (including the amount of any borrowings for investment purposes) in equity securities of companies that have market capitalizations in the range of the companies in the Russell Midcap^® Value Index that the fund’s investment adviser believes are undervalued and have the potential for long-term growth.

■ The fund may hold a small number of securities, consistent with its value investment approach. Generally, the fund anticipates holding between 30 and 50 securities in its portfolio; however, the fund may hold, at any time, more or fewer securities than noted in this range.

■ The fund may invest up to 20% of its total assets in foreign securities.

■ The fund normally invests in common stocks and also may invest in real estate investment trusts.

■ The fund may from time to time emphasize one or more sectors in selecting its investments, including the financial services sector.

■ The principal risks of the fund include Active Management Risk, Focused Portfolio Risk, Foreign Securities Risk, Issuer Risk (including Mid-Cap Stock Risk), Market Risk, Real Estate-Related Investment Risk, Sector Risk (including the Financial Services sector), and Value Securities Risk.

Columbia Short Term Bond Fund

■ The fund seeks current income, consistent with minimal fluctuation of principal.

■ Under normal circumstances, the fund invests at least 80% of its net assets (including the amount of any borrowings for investment purposes) in bonds, including debt instruments issued by the U.S. Government and its agencies, debt securities issued by corporations, mortgage- and other asset-backed securities, and dollar-denominated securities issued by foreign governments, companies or other entities.

■ The fund invests at least 65% of its total assets in securities that, at the time of purchase, are rated investment grade or are unrated but determined to be of comparable quality.

■ The fund may invest in mortgage- and other asset-backed securities.

36 Prospectus 2022

Columbia Thermostat Fund^SM

Portfolio Funds Summary (continued)

■ The fund may invest in floating rate debt securities, which have interest rates that adjust or “float” periodically.

■ The fund may invest in derivatives, such as futures (including interest rate futures), for both hedging and non-hedging purposes including, for example, to seek to enhance returns or as a substitute for a position in an underlying asset, as well as to manage portfolio duration.

■ The fund may invest in privately placed and other securities or instruments that are purchased and sold pursuant to Rule 144A or other exemptions under the Securities Act of 1933, as amended, subject to liquidity determinations and certain regulatory restrictions.

■ The fund may purchase or sell securities on a when-issued, delayed delivery or forward commitment basis. Such securities may include mortgage-backed securities acquired or sold in the “to be announced” (TBA) market and those in a dollar roll transaction.

■ Under normal circumstances, the fund’s dollar-weighted average effective maturity will be three years or less, and its duration will be three years or less.

■ The fund's investment strategy may involve the frequent trading of portfolio securities.

■ The principal risks of the fund include Active Management Risk, Changing Distribution Level Risk, Counterparty Risk, Credit Risk, Derivatives Risk, Derivatives Risk – Futures Contracts Risk, Foreign Securities Risk, Forward Commitments on Mortgage-Backed Securities (including Dollar Rolls) Risk, Frequent Trading Risk, High-Yield Investments Risk, Interest Rate Risk, Issuer Risk, LIBOR Replacement Risk, Liquidity Risk, Market Risk, Mortgage- and Other Asset-Backed Securities Risk, Prepayment and Extension Risk, Reinvestment Risk, Rule 144A and Other Exempted Securities Risk, Sovereign Debt Risk, and U.S. Government Obligations Risk.

Columbia Total Return Bond Fund

■ The fund seeks total return, consisting of current income and capital appreciation.

■ Under normal circumstances, the fund invests at least 80% of its net assets (including the amount of any borrowings for investment purposes) in bonds, notes and other debt instruments, including derivatives relating to such investments.

■ The fund may invest up to 35% of its net assets in debt instruments that, at the time of purchase, are rated below investment grade or are unrated but determined to be of comparable quality (commonly referred to as “high-yield” investments or “junk” bonds).

■ The fund may invest in debt instruments issued by U.S. and non-U.S. governments, their agencies, authorities or instrumentalities, U.S. and non-U.S. corporate or other non-governmental entities, as well as mortgage- and other asset-backed securities.

■ The fund generally expects to maintain an effective duration of +/- 2 years relative to the Bloomberg U.S. Aggregate Bond Index.

■ The fund may invest in derivatives, such as futures (including interest rate futures) and swaps (including credit default swaps, credit default swap indexes, and interest rate swaps) for hedging and investment purposes, and to manage interest rate and/or credit exposure of the fund.

■ The fund may purchase or sell securities on a when-issued, delayed delivery or forward commitment basis. Such securities may include mortgage-backed securities acquired or sold in the “to be announced” (TBA) market and those in a dollar roll transaction.

■ The fund’s investments in mortgage-related securities include investments in stripped mortgage-backed securities such as interest-only (IO) and principal-only (PO) securities.

■ The fund may invest in privately placed and other securities or instruments that are purchased and sold pursuant to Rule 144A or other exemptions under the Securities Act of 1933, as amended, subject to certain regulatory restrictions.

■ The fund’s investment strategy may involve the frequent trading of portfolio securities.

Prospectus 2022 37

Columbia Thermostat Fund^SM

Portfolio Funds Summary (continued)

■ The principal risks of the fund include Active Management Risk, Changing Distribution Level Risk, Counterparty Risk, Credit Risk, Derivatives Risk, Derivatives Risk – Futures Contracts Risk, Derivatives Risk – Swaps Risk, Foreign Securities Risk, Forward Commitments on Mortgage-Backed Securities (including Dollar Rolls) Risk, Frequent Trading Risk, High-Yield Investments Risk, Interest Rate Risk, Issuer Risk, Leverage Risk, LIBOR Replacement Risk, Liquidity Risk, Market Risk, Mortgage- and Other Asset-Backed Securities Risk, Prepayment and Extension Risk, Reinvestment Risk, Rule 144A and Other Exempted Securities Risk, Sovereign Debt Risk, Stripped Mortgage-Backed Securities Risk, and U.S. Government Obligations Risk.

Columbia U.S. Treasury Index Fund

■ The fund seeks total return that corresponds to the total return of the FTSE USBIG Treasury Index, before fees and expenses.

■ Under normal circumstances, the fund invests at least 80% of its net assets (including the amount of any borrowings for investment purposes) in securities that comprise the FTSE USBIG Treasury Index, which is an unmanaged index composed of U.S. Treasury notes and bonds with remaining maturities of at least one year and outstanding principal of at least $5 billion and which are included in the FTSE U.S. Broad Investment-Grade Bond Index.

■ Different securities have different weightings in the FTSE USBIG Treasury Index and are weighted by market value; that is, the price per bond or note multiplied by the number of bonds or notes outstanding.

■ In seeking to match the performance of the FTSE USBIG Treasury Index, before fees and expenses, the fund’s investment adviser attempts to allocate the fund’s assets among securities in the FTSE USBIG Treasury Index. The fund will not hold all of the securities in the FTSE USBIG Treasury Index.

■ The principal risks of the fund include Correlation/Tracking Error Risk, Credit Risk, Interest Rate Risk, Market Risk, Passive Investment Risk, and U.S. Government Obligations Risk.

38 Prospectus 2022

Columbia Thermostat Fund^SM

More Information About the Fund

Investment Objective

Columbia Thermostat Fund^SM (the Fund) seeks long-term capital appreciation. The Fund’s investment objective is not a fundamental policy of the Fund and may be changed by the Fund’s Board of Trustees (the Board) without shareholder approval. There is no assurance the Fund’s objective will be achieved.

Additional Investment Strategies and Policies

This section describes certain investment strategies and policies that the Fund may utilize in pursuit of its investment objective and some additional factors and risks involved with investing in the Fund. For information about risks associated with changing levels of Fund distributions, see the SAI.

Changing the Fund’s Investment Objective and Policies

The Fund’s investment objective and non-fundamental investment policies (including its principal and additional investment strategies) can be changed by the Board without shareholder approval, but may require notice to shareholders in certain instances. The Fund’s fundamental investment policies, as identified in the Fund’s Statement of Additional Information (SAI), may be changed only with Board and shareholder approval in accordance with the voting requirements of the 1940 Act. For additional information about changing the Fund’s fundamental and non-fundamental investment policies, see the SAI.

Investment Guidelines

As a general matter, and except as specifically described in the discussion of the Fund's principal investment strategies in this prospectus, whenever an investment policy or limitation states a percentage of the Fund's assets that may be invested in any security or other asset or sets forth a policy regarding an investment standard, compliance with that percentage limitation or standard will be determined based on the characteristics of a company at the time of initial purchase, and subsequent changes in a characteristic are not taken into account.

Holding Other Kinds of Investments

The Fund may hold other investments that are not part of its principal investment strategies. These investments and their risks are described below and/or in the Statement of Additional Information (SAI). The Fund may choose not to invest in certain securities described in this prospectus and in the SAI, although it has the ability to do so. Information on the Fund’s holdings can be found in the Fund’s shareholder reports or by visiting columbiathreadneedleus.com.

Transactions in Derivatives

The Fund may enter into derivative transactions or otherwise have exposure to derivative transactions through underlying investments. The Fund expects to enter into such transactions primarily in the form of stock index futures in order to obtain exposure to the overall sector of the market represented by a particular stock index or to invest the Fund’s uninvested cash balances in a manner that the Investment Manager believes aligns more closely with the Fund’s investment strategy than simply holding short-term fixed income investments or cash equivalents (known as cash equitization). Derivatives are financial contracts whose values are, for example, based on (or “derived” from) traditional securities (such as a stock or bond), assets (such as a commodity like gold or a foreign currency), reference rates (such as the Secured Overnight Financing Rate (commonly known as SOFR) or the London Interbank Offered Rate (commonly known as LIBOR)) or market indices (such as the Standard & Poor's (S&P) 500^® Index). The use of derivatives is a highly specialized activity which involves investment techniques and risks different from those associated with ordinary portfolio securities transactions. Derivatives involve special risks and may result in losses or may limit the Fund's potential gain from favorable market movements. Derivative strategies typically expose the Fund to gains and losses in excess of the amount actually invested in the derivative. This characteristic of a derivative (known as "leverage") may exaggerate a loss, potentially causing the Fund to lose more money than it would have lost had it invested in the underlying security or other asset directly. The values of derivatives may move in unexpected ways, especially in unusual (including distressed) market conditions, and may result in increased volatility in the value of the derivative and/or the Fund’s shares, among other consequences. The use of derivatives may also increase the amount of taxes payable by shareholders holding shares in a taxable account. Other risks

Prospectus 2022 39

Columbia Thermostat Fund^SM

More Information About the Fund (continued)

arise from the Fund's potential inability to terminate or to sell derivative positions. A liquid secondary market may not always exist for the Fund's derivative positions at times when the Fund might wish to terminate or to sell such positions. Over-the-counter instruments (investments not traded on an exchange) may be illiquid, and transactions in derivatives traded in the over-the-counter market are subject to the risk that the other party will not meet its obligations. The use of derivatives also involves the risks of mispricing or improper valuation and that changes in the value of the derivative may not correlate perfectly with the underlying security, asset, reference rate or index. The Fund also may not be able to find a suitable derivative transaction counterparty, and thus may be unable to engage in derivative transactions when it is deemed favorable to do so, or at all. U.S. federal legislation has been enacted that provides for new clearing, margin, reporting and registration requirements for participants in the derivatives market. These changes could restrict and/or impose significant costs or other burdens upon the Fund’s participation in derivatives transactions. The U.S. government and the European Union (and some other jurisdictions) have enacted regulations and similar requirements that prescribe clearing, margin, reporting and registration requirements for participants in the derivatives market. These requirements are evolving and their ultimate impact on the Fund remains unclear but such impact could include restricting and/or imposing significant costs or other burdens upon the Fund’s participation in derivatives transactions. Additionally, in October 2020, the SEC adopted new regulations governing the use of derivatives by registered investment companies. Once effective, Rule 18f-4 will, among other things, require funds that invest in derivative instruments beyond a specified limited amount to apply a value-at-risk based limit to their use of certain derivative instruments and establish a comprehensive derivatives risk management program. A fund that uses derivative instruments in a limited amount will not be subject to the full requirements of Rule 18f-4. Compliance with Rule 18f-4 will not be required until August 2022. Rule 18f-4 could have an adverse impact on the Fund’s performance and ability to implement its investment strategies as it has historically. For more information on the risks of derivative investments and strategies, see the SAI.

LIBOR Phase-Out Risk. Many derivatives and other financial instruments utilize or are permitted to utilize a floating interest rate based on LIBOR. On July 27, 2017, the United Kingdom's Financial Conduct Authority (FCA) announced its intention to phase out the use of LIBOR by the end of 2021. The FCA and the ICE Benchmark Administration have since announced that a majority of U.S. dollar LIBOR settings will cease publication after June 30, 2023. A subset of non-U.S. dollar LIBOR settings are continuing to be published on a “synthetic” basis and it is possible that a subset of U.S. dollar LIBOR settings will also be published after June 30, 2023 on a “synthetic” basis. Any such publications are, or would be considered, non-representative of the underlying market. Uncertainty related to the liquidity impact of changes in reference rates, and how to appropriately adjust these rates at the time of transition, poses risks for the Fund. It is difficult to predict the full impact of the transition away from LIBOR on the Fund until new reference rates and fallbacks for both legacy and new products, instruments and contracts are commercially accepted and market practices become more settled. The Investment Manager monitors the Fund's LIBOR exposure risks, including the extent to which any derivative and/or debt investments allow for the utilization of alternative rate(s), such as the Secured Overnight Financing Rate (SOFR), which the U.S. Federal Reserve is promoting as the alternative reference rate to LIBOR.

Affiliated Fund Investing

The Investment Manager and its affiliate, Columbia Management Investment Advisers, LLC (Columbia Management), each serves as investment adviser to mutual funds and ETFs using the Columbia brand (Columbia Funds), including mutual funds that are structured as “fund-of-funds”, and provides asset-allocation services to (i) shareholders by investing in shares of other Columbia Funds (collectively referred to in this section as Portfolio Funds), and (ii) discretionary managed accounts (collectively referred to as affiliated products) that invest exclusively in Portfolio Funds. These affiliated products, individually or collectively, may own a significant percentage of the outstanding shares of one or more Portfolio Funds, and the Investment Manager and Columbia Management seek to balance potential conflicts of interest between the affiliated products and the Portfolio Funds in which they invest. The affiliated products’ investment in the Portfolio Funds may have the effect of creating economies of scale, possibly resulting in lower expense ratios for the Portfolio Funds, because the affiliated products may own substantial portions of the shares of Portfolio Funds. However, redemption of Portfolio Fund shares by one or more affiliated products could cause the expense ratio of the Portfolio Fund to increase, as its fixed costs would be spread over a smaller asset base. Because of large positions of certain affiliated products, the Portfolio Funds may experience

40 Prospectus 2022

Columbia Thermostat Fund^SM

More Information About the Fund (continued)

relatively large inflows and outflows of cash due to affiliated products’ purchases and sales of Portfolio Fund shares. Although the Investment Manager or Columbia Management may seek to minimize the impact of these transactions where possible, for example, by structuring them over a reasonable period of time or through other measures, Portfolio Funds may experience increased expenses as they buy and sell portfolio securities to manage the cash flow effect related to these transactions. Further, when the Investment Manager or Columbia Management structures transactions over a reasonable period of time in order to manage the potential impact of the buy and sell decisions for the affiliated products, those affiliated products, including funds-of-funds, may pay more or less (for purchase activity), or receive more or less (for redemption activity), for shares of the Portfolio Funds than if the transactions were executed in one transaction. In addition, substantial redemptions by affiliated products within a short period of time could require the Portfolio Fund to liquidate positions more rapidly than would otherwise be desirable, which may have the effect of reducing or eliminating potential gain or causing it to realize a loss. In order to meet such redemptions, the Portfolio Fund may be forced to sell its liquid (or more liquid) positions, leaving the Portfolio Fund holding, post-redemption, a relatively larger position in illiquid investments (i.e., any investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without the sale or disposition significantly changing the market value of the investment) or less liquid securities. Substantial redemptions may also adversely affect the ability of the Portfolio Fund to implement its investment strategy. The Investment Manager or Columbia Management also has a conflict of interest in determining the allocation of affiliated products’ assets among the Underlying Funds, as it earns different fees from the various Portfolio Funds.

Investing in Money Market Funds

The Fund may invest cash, including cash collateral received in connection with its securities lending program, in shares of money market funds, including funds advised by affiliates of the Investment Manager. These funds are not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency. The Fund and its shareholders indirectly bear a portion of the expenses of any money market fund or other fund in which the Fund may invest.

Lending of Portfolio Securities

Columbia Acorn^® Fund may lend portfolio securities to broker-dealers or other financial intermediaries on a fully collateralized basis in order to earn additional income. Columbia Acorn^® Fund may lose money from securities lending if, for example, the borrower does not return a loaned security and the proceeds from sale of the collateral are not sufficient to replace the borrowed security. Columbia Acorn^® Fund invests collateral in a government money market fund.

Investing Defensively

The Fund may from time to time take temporary defensive investment positions that are inconsistent with the Fund’s principal investment strategies in attempting to respond to adverse market, economic, political, social or other conditions. These investment positions may include, without limitation, investing some or all of its assets in money market instruments or shares of affiliated or unaffiliated money market funds or holding some or all of its assets in cash or cash equivalents. The Fund may take such defensive positions for as long a period as the Investment Manager deems necessary. During these times, the Investment Manager may make frequent portfolio changes, which could result in increased trading expenses and taxes, and decreased Fund performance.

Portfolio Holdings Disclosure

A description of the Fund’s policies and procedures with respect to the disclosure of Fund portfolio securities is available in the SAI. The Fund discloses its portfolio holdings on the Columbia Funds’ website, columbiathreadneedleus.com, as described below. Once posted, the portfolio holdings information will remain available on the website until at least the date on which such Fund files a Form N-CSR or publicly available Form N-PORT (forms filed with the SEC that include portfolio holdings information) for the period that includes the date as of which the information is current.

Prospectus 2022 41

Columbia Thermostat Fund^SM

More Information About the Fund (continued)

The Fund considers changes in its portfolio holdings to be confidential information. Consequently, Fund policy generally permits the disclosure of portfolio holdings information only after a certain amount of time has passed. The Fund’s complete portfolio holdings are disclosed approximately 30 to 40 days after each month-end. The top 15 holdings may be available sooner, approximately 15 calendar days after each month-end. Purchases and sales of portfolio securities can take place at any time, so the portfolio holdings information available on the website may not always be current.

Cybersecurity

The Fund, like all companies, may be susceptible to operational and information security risks, including the risk of cyber attacks or failures. As a result, the Fund or its service providers, or the issuers of securities in which the Fund invests, may experience disruptions in business operations that may potentially result in financial losses, the inability of the Fund or Fund shareholders to transact business, violations of applicable privacy and other laws, regulatory fines, penalties, reputational damage, reimbursement or other compensation costs, and/or additional compliance costs. The Fund and its shareholders could be negatively impacted as a result. See the discussion of Cybersecurity Breaches and Technology and Related Systems Failure Risk in the SAI for further information.

Use of Benchmarks

Benchmarks are indices that provide some comparative guidance in assessing the Fund’s performance. The Investment Manager selects the benchmarks it believes provide meaningful comparisons for each Fund. However, there may be different or additional indices that more closely reflect the market sectors in which the Fund invests. The Fund’s benchmarks may change from time to time. The benchmarks included in this prospectus are intended only as guideposts for your assessment of the Fund’s performance.

 FUNDamentals

Portfolio Holdings Versus the Benchmarks

The Fund does not limit its investments to the securities within its benchmarks, and accordingly the Fund's holdings may diverge significantly from those of the benchmarks selected by the Investment Manager. In addition, the Fund may invest in securities outside the industry and geographic sectors represented in its benchmarks. The Fund's weightings in individual securities, and in industry and geographic sectors, may also vary considerably from those of its benchmarks.

eDelivery and Mailings to Households

In order to reduce shareholder expenses, the Fund may mail only one copy of the Fund’s prospectus and each annual and semiannual report to those addresses shared by two or more accounts. If you wish to receive separate copies of these documents, call 800.345.6611 or, if your shares are held through a financial intermediary, contact your intermediary directly. Additionally, you may elect to enroll in eDelivery to receive electronic versions of these documents, as well as quarterly statements and supplements, by logging into your account at columbiathreadneedleus.com/investor/.

Additional Information on Portfolio Turnover

Because Columbia Thermostat Fund is a fund-of-funds that exchanges shares of the underlying Portfolio Funds at net asset value, the costs associated with the Fund’s portfolio turnover rate are lower than the costs that would be associated with another fund that had the same portfolio turnover rate but directly bore the trading costs of its portfolio transactions. See the Financial Highlights section of this prospectus for the Fund's portfolio turnover rates for the past five years.

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Columbia Thermostat Fund^SM

More Information About the Fund (continued)

Cash Flows

The timing and magnitude of cash inflows from investors buying Fund shares could prevent the Fund from always being fully invested. Conversely, the timing and magnitude of cash outflows to shareholders redeeming Fund shares could require the Fund to sell portfolio securities at less than opportune times or to hold ready reserves of uninvested cash in amounts larger than might otherwise be the case to meet shareholder redemptions. Either situation could adversely impact the Fund’s performance.

Understanding Annual Fund Operating Expenses

The Fund’s annual operating expenses, as presented in the Annual Fund Operating Expenses table in the Fees and Expenses of the Fund section of this prospectus, generally are based on expenses incurred during the Fund’s most recently completed fiscal year, may vary by share class and are expressed as a percentage (expense ratio) of the Fund’s average net assets during that fiscal year. The expense ratios reflect the Fund’s fee arrangements as of the date of this prospectus and, unless indicated otherwise, are based on expenses incurred during the Fund’s most recent fiscal year. The Fund’s assets will fluctuate, but unless indicated otherwise in the Annual Fund Operating Expenses table, no adjustments have been or will be made to the expense ratios to reflect any differences in the Fund’s average net assets between the most recently completed fiscal year and the date of this prospectus or a later date. In general, the Fund’s expense ratios will increase as its net assets decrease, such that the Fund’s actual expense ratios may be higher than the expense ratios presented in the Annual Fund Operating Expenses table if assets fall. Any commitment by the Investment Manager and/or its affiliates to waive fees and/or cap (reimburse) expenses is expected, in part, to limit the impact of any increase in the Fund’s expense ratios that would otherwise result because of a decrease in the Fund’s assets in the current fiscal year. The Fund’s annual operating expenses are comprised of (i) investment management fees, (ii) distribution and/or service fees, and (iii) other expenses. Management fees do not vary by class, but distribution and/or service fees and other expenses may vary by class. Please see Fee Waiver/Expense Reimbursement Arrangements below for information about commitments made by the Investment Manager and/or its affiliates during the performance period covered by this prospectus.

 FUNDamentals

Other Expenses

“Other expenses” consist of the fees the Fund pays to its administrator, custodian, transfer agent, auditors, lawyers and trustees, costs relating to compliance and miscellaneous expenses. Generally, these expenses are allocated on a pro rata basis across all share classes. These expenses include certain sub-transfer agency and shareholder servicing fees. Transfer agency fees and certain shareholder servicing fees, however, are class specific. They differ by share class because the shareholder services provided to each share class may be different. Accordingly, the differences in “other expenses” among share classes are primarily the result of the different transfer agency and shareholder servicing fees applicable to each share class. For more information on these fees, see Choosing a Share Class — Financial Intermediary Compensation.

Fee Waiver/Expense Reimbursement Arrangements

The Investment Manager has contractually agreed to waive fees and reimburse certain expenses of the Fund so that ordinary operating expenses (excluding transaction costs and certain other investment-related expenses, interest and fees on borrowings and expenses associated with the Fund's investment in other investment companies, including the Portfolio Funds (acquired funds)) do not exceed the annual rates shown below through April 30, 2023. This arrangement may only be amended or terminated with approval from the Fund’s Board of Trustees and the Investment Manager.

The effective expense ratio for the Fund, gross of the contractual waiver/reimbursement discussed above, will vary in connection with the changes to the Portfolio Funds and to the allocation of the Fund’s assets among the Portfolio Funds, which the Investment Manager may make to from time to time, as described above under Principal Investment Strategies.

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Columbia Thermostat Fund
Class A	0.50%
Class Adv	0.25%
Class C	1.25%
Class Inst	0.25%
Class Inst2	0.20%
Class Inst3	0.16%

Effect of Fee Waivers and/or Expense Reimbursements on Past Performance. The Fund’s returns shown in the Performance Information section of this prospectus reflect the effect of fee waivers and/or reimbursements of Fund expenses by the Investment Manager and/or its affiliates that were in place during the performance period shown in the Performance Information section of this prospectus. Without such fee waivers/expense reimbursements, the Fund’s returns might have been lower.

Board of Trustees

The Fund is governed by the Board. More than 75% of the Fund's Trustees are independent (Independent Trustees), meaning that they are not “interested persons” of the Fund, as defined in the 1940 Act. The Independent Trustees bring backgrounds in business and academia to their task of working with the Fund's officers to establish the Fund's policies and oversee its activities. Among the Trustees' responsibilities are: selecting the investment adviser for the Fund; approving the advisory agreement; reviewing other contracts; approving investment policies; monitoring Fund operations, performance, compliance and costs; and nominating or selecting new Trustees.

Each Trustee serves the Fund for an indefinite term until his or her retirement, resignation, death or removal in accordance with the organizational documents of Columbia Acorn Trust (the Trust). The Trust's Bylaws generally require that Trustees retire at the end of the calendar year in which they attain the age of 75 years. The last meeting to elect Trustees was held on February 27, 2015. Any Trustee may be removed at a shareholders' meeting by a vote representing two-thirds of the net asset value of all shares of the Columbia Acorn family of funds (Columbia Acorn Funds). The mailing address for the Trustees and officers is 71 S. Wacker Drive, Suite 2500, Chicago, Illinois 60606.

For more detailed information about the Board, please refer to the SAI.

Primary Service Provider Contracts

The Fund enters into contractual arrangements (Service Provider Contracts) with various parties, including, among others, the Investment Manager, the Distributor, the Transfer Agent and the Fund’s custodian. The Fund’s Service Provider Contracts are solely among the parties thereto. Shareholders are not parties to, or intended to be third-party beneficiaries of, any Service Provider Contracts. Further, this prospectus, the SAI and any Service Provider Contracts are not intended to give rise to any agreement, duty, special relationship or other obligation between the Fund and any investor, or give rise to any contractual, tort or other rights in any individual shareholder, group of shareholders or other person, including any right to assert a fiduciary or other duty, enforce the Service Provider Contracts against the parties or to seek any remedy thereunder, either directly or on behalf of the Fund. Nothing in the previous sentence should be read to suggest any waiver of any rights under federal or state securities laws.

The Investment Manager, which also serves as the Fund's administrator (the Administrator), Columbia Management, which serves as the Fund's sub-administrator pursuant to an agreement with the Investment Manager (the Sub-Administrator), the Distributor, and the Transfer Agent are all affiliates of Ameriprise Financial. They and their affiliates currently provide key services, including investment advisory, administration, distribution, shareholder servicing and transfer agency services, to the Fund and various other funds, including the Columbia Funds, and are paid for providing these services. These service relationships are described below.

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The Investment Manager

Columbia Wanger Asset Management, LLC is located at 71 S. Wacker Drive, Suite 2500, Chicago, Illinois 60606. As of March 31, 2022, the Investment Manager had assets under management of approximately $9.2 billion. The Investment Manager is a registered investment adviser and wholly-owned subsidiary of Columbia Management, which is a wholly-owned subsidiary of Ameriprise Financial. In addition to serving as an investment adviser to mutual funds, the Investment Manager acts as an investment manager for other private funds and institutional accounts.

Subject to oversight by the Board, the Investment Manager manages the day-to-day operations of the Fund, determining what securities and other investments the Fund should buy or sell and executing portfolio transactions. The Investment Manager may use the research and other capabilities of its affiliates and third parties in managing the Fund’s investments.

The Fund pays the Investment Manager a fee for its investment advisory services. The fee is calculated as a percentage of the daily net assets of the Fund and is paid monthly. For the Fund’s most recent fiscal year, aggregate fees paid to the Investment Manager by the Fund amounted to 0.10% of average daily net assets of the Fund, before any applicable reimbursements.

A discussion regarding the basis for the Board’s approval of the renewal of the Fund’s investment management services agreement with the Investment Manager is available in the Fund’s annual report to shareholders for the fiscal year ended December 31, 2021.

The Investment Manager and its investment advisory affiliates, including Columbia Management (Affiliates), around the world may coordinate in providing services to their clients. From time to time, the Investment Manager may engage its Affiliates to provide a variety of services such as investment research, investment monitoring, trading, and discretionary investment management (including portfolio management and proxy voting) to certain accounts managed by the Investment Manager, including the Fund. These Affiliates will provide services to the Fund and other accounts of the Investment Manager either pursuant to delegation agreements, personnel-sharing agreements or similar inter-company or other arrangements or relationships and the Fund will pay no additional fees and expenses as a result of any such arrangements or relationships. These Affiliates, like the Investment Manager, are direct or indirect subsidiaries of Ameriprise Financial and are registered with the appropriate respective regulators and, where required, the SEC and the Commodity Futures Trading Commission in the United States.

Pursuant to some of these arrangements or relationships, certain personnel of Columbia Management and other Affiliates may serve as “associated persons” or officers of the Investment Manager and, in this capacity, subject to the oversight and supervision of the Investment Manager and consistent with the investment objectives, policies and limitations set forth in this prospectus and the Fund's SAI, and with the Investment Manager’s and the Funds’ compliance policies and procedures, may provide such services to the Fund.

Portfolio Managers

Information about the portfolio managers primarily responsible for overseeing the Fund’s investments is shown below. The SAI provides additional information about the portfolio managers, including information relating to compensation, other accounts managed by the portfolio managers, and ownership by the portfolio managers of Fund shares.

Portfolio Management	Title	Role with Fund	Service with the Fund Since
Anwiti Bahuguna, Ph.D.	Senior Portfolio Manager and Head of Multi Asset Strategy of Columbia Management and Assistant Vice President of the Investment Manager	Lead Portfolio Manager or Co-Portfolio Manager since 2018	2018
Alex M. Rivas	Portfolio Manager of Columbia Management and Assistant Vice President of the Investment Manager	Portfolio Manager since May 2022	2018

Dr. Bahuguna joined Columbia Management, an affiliate of the Investment Manager, or one of its legacy firms or acquired business lines in 2002. Dr. Bahuguna has served as Assistant Vice President of the Investment Manager since May 2018. Dr. Bahuguna began her investment career in 1998 and earned a B.S. from St. Stephen’s College, Delhi University and a Ph.D. in economics from Northeastern University.

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Mr. Rivas joined Columbia Management, an affiliate of the Investment Manager in 2017. Mr. Rivas has served as Assistant Vice President of the Investment Manager since February 2018. Prior to joining Columbia Management, Mr. Rivas was a trading specialist with Blackrock Advisors, LLC. Mr. Rivas began his investment career in 2009 and earned a B.S. from Georgia Institute of Technology and a Master’s degree in Finance from Princeton University.

The Administrator

Columbia Wanger Asset Management, LLC is responsible for overseeing the administrative operations of the Fund, including the general supervision of the Fund’s operations, coordination of the Fund’s service providers, and the provision of office facilities and related clerical and administrative services. The Administrator retains the Sub-Administrator to perform many of these services (including fund accounting), and pays a fee for the services of the Sub-Administrator. The Fund pays the Administrator a fee for its services, plus certain out-of-pocket expenses. The fee is calculated as an annual percentage of the Trust’s aggregate average daily net assets and is paid monthly, as follows:

Annual Administration Fee, as a % of Aggregate Daily Net Assets of the Trust:
Up to $8 billion	0.050%
$8 billion to $16 billion	0.040%
$16 billion to $35 billion	0.030%
$35 billion to $45 billion	0.025%
$45 billion and over	0.015%

The Distributor

Shares of the Fund are distributed by Columbia Management Investment Distributors, Inc., which is located at 290 Congress Street, Boston, MA 02210. The Distributor is a registered broker-dealer and an indirect, wholly-owned subsidiary of Ameriprise Financial. The Distributor and its affiliates may pay commissions, distribution and service fees and/or other compensation to entities, including Ameriprise Financial affiliates, for selling shares and providing services to investors.

The Transfer Agent

Columbia Management Investment Services Corp. is a registered transfer agent and wholly-owned subsidiary of Ameriprise Financial. The Transfer Agent is located at 290 Congress Street, Boston, MA 02210, and its responsibilities include processing purchases, redemptions and exchanges of Fund shares, calculating and paying distributions, maintaining shareholder records, preparing account statements and providing customer service. The Transfer Agent has engaged DST Asset Manager Solutions, Inc. to provide various shareholder or “sub-transfer agency” services. In addition, the Transfer Agent enters into agreements with various financial intermediaries through which you may hold Fund shares, pursuant to which the Transfer Agent pays these financial intermediaries for providing certain shareholder services. Depending on the type of account, the Fund pays the Transfer Agent a per account fee for each open account and compensates the Transfer Agent for certain out-of-pocket expenses, including certain payments to financial intermediaries through which shares are held. In addition, subject to certain limitations, the Fund compensates the Transfer Agent for payments made to financial intermediaries for the shareholder services that the intermediaries provide, in amounts that vary by share class and with the type of intermediary and the type of shareholder services provided. The Transfer Agent is contractually obligated to oversee such intermediaries for the purpose of reasonably assuring their compliance with applicable law and the terms of their agreements to provide the shareholder services. For more information about Shareholder Services fees, see Choosing a Share Class — Financial Intermediary Compensation.

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Other Roles and Relationships of Ameriprise Financial and its Affiliates — Certain Conflicts of Interest

This section describes certain actual and potential conflicts of interest that arise from the financial services activities of Ameriprise Financial and its affiliates. Ameriprise Financial is a major financial services company, engaged in a broad range of financial activities beyond the fund-related activities of the Investment Manager, including: insurance, broker-dealer (sales and trading), asset management and financial services. As a consequence of these activities, Ameriprise Financial or its affiliates may have interests arising from their other business lines that conflict with the interests of the Fund. These activities may also, from time to time, place certain investment constraints on the management of the Fund that might not otherwise arise.

As described in More Information About the Fund - Primary Service Provider Contracts, the Investment Manager, Administrator, Sub-Administrator, Distributor and Transfer Agent are all affiliates of Ameriprise Financial. In addition to the services that they provide to the Fund, they also provide substantially similar services (for which they are compensated) to other clients and customers, including the Columbia Funds. Ameriprise Financial and its other affiliates may also provide services (for which they are compensated) to the Fund, other Columbia Funds or other clients and customers.

Examples of activities that could lead to conflicts of interest and/or impose limitations that could affect the Fund include the following:

■ the Investment Manager and other Ameriprise Financial affiliates may receive compensation and other benefits related to the management/administration of the Fund and the other Columbia Funds and the sale of their shares;

■ there may be competition for limited investment opportunities that must be allocated among the Fund, the other Columbia Funds and other clients and customers of the Investment Manager (which can include affiliates of the Investment Manager) that may have the same or similar investment objectives as the Fund;

■ management of the Fund may diverge from other Columbia Funds or other clients and customers of the Investment Manager or Ameriprise Financial affiliates, for example, advice given to the Fund may differ from, or conflict with, advice given to other funds or accounts;

■ there may be regulatory or investment restrictions imposed on the investment activities of the Investment Manager arising from the activities or holdings of other Columbia Funds or other clients or customers of the Investment Manager or Ameriprise Financial and its affiliates, for example, caps on the aggregate amount of certain types of investments or in holdings of particular portfolio companies that may be made by affiliated entities, including the Fund;

■ Ameriprise Financial or its affiliates may have potentially conflicting relationships with companies and other entities in which the Fund invests; and

■ there may be regulatory and other restrictions relating to the sharing of information between Ameriprise Financial and its affiliates, including the Investment Manager, for example, if an affiliated entity were in possession of non-public information, the Investment Manager might be prohibited by law from using that information in connection with the management of the Fund.

The Investment Manager and Ameriprise Financial have adopted various policies and procedures that are intended to identify, monitor and address conflicts of interest. However, there is no absolute assurance that these policies, procedures and disclosures will be effective.

Additional information about Ameriprise Financial and the types of conflicts of interest and other matters referenced above is set forth in the Investment Advisory and Other Services – Other Roles and Relationships of Ameriprise Financial and Affiliates – Certain Conflicts of Interest section of the SAI. Investors in the Fund should carefully review these disclosures and consult with their financial advisor if they have any questions.

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Certain Legal Matters

Ameriprise Financial and certain of its affiliates are involved in the normal course of business in legal proceedings which include regulatory inquiries, arbitration and litigation, including class actions concerning matters arising in connection with the conduct of its activities as a diversified financial services firm. Ameriprise Financial believes that the Fund is not currently the subject of, and that neither Ameriprise Financial nor any of its affiliates are the subject of, any pending legal, arbitration or regulatory proceedings that are likely to have a material adverse effect on the Fund or the ability of Ameriprise Financial or its affiliates to perform under their contracts with the Fund. Information regarding certain pending and settled legal proceedings may be found in the Fund’s shareholder reports and in the SAI. Additionally, Ameriprise Financial is required to make quarterly (10-Q), annual (10-K) and, as necessary, 8-K filings with the SEC on legal and regulatory matters that relate to Ameriprise Financial and its affiliates. Copies of these filings may be obtained by accessing the SEC website at sec.gov.

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The Funds

The Columbia Acorn Funds and the other Columbia Funds generally share the same policies and procedures for investor services, as described below. Together, the Fund and the other Columbia Acorn Funds, along with the Columbia Funds, are referred to herein as the Funds.

Funds Contact Information

Additional information about the Funds, including sales charges and other class features and policies, can be obtained, free of charge, at columbiathreadneedleus.com,* by calling toll-free 800.345.6611, or by writing (regular mail) to Columbia Management Investment Services Corp., P.O. Box 219104, Kansas City, MO 64121-9104 or (express mail) Columbia Management Investment Services Corp., c/o DST Asset Manager Solutions, Inc., 430 W 7^th Street, Ste 219104, Kansas City, MO 64105-1407.

* The website references in this prospectus are inactive links and information contained in or otherwise accessible through the referenced websites does not form a part of this prospectus.

 FUNDamentals

Financial Intermediaries

The term “financial intermediary” refers to the selling and servicing agents that are authorized to sell and/or service shares of the Funds. Financial intermediaries include broker-dealers and financial advisors as well as firms that employ broker-dealers and financial advisors, including, for example, brokerage firms, banks, investment advisers, third party administrators and other firms in the financial services industry.

Omnibus Accounts

The term “omnibus account” refers to a financial intermediary’s account with the Fund (held directly through the Transfer Agent) that represents the combined holdings of, and transactions in, Fund shares of one or more clients of the financial intermediary (beneficial Fund shareholders). Omnibus accounts are held in the name of the financial intermediaries and not in the name of the beneficial Fund shareholders invested in the Fund through omnibus accounts.

Retirement Plans and Omnibus Retirement Plans

The term “retirement plan” refers to retirement plans created under Sections 401(a), 401(k), 457 and 403(b) of the Internal Revenue Code of 1986, as amended (the Code), and non-qualified deferred compensation plans governed by Section 409A of the Code and similar plans, but does not refer to individual retirement plans, such as traditional IRAs and Roth IRAs. The term “omnibus retirement plan” refers to a retirement plan that has a plan-level or omnibus account with the Transfer Agent.

Networked Accounts

Networking, offered by the Depository Trust & Clearing Corporation’s Wealth Management Services (WMS), is the industry standard IT system for mutual fund account reconciliation and dividend processing.

Summary of Share Class Features

Each share class has its own investment eligibility criteria, cost structure and other features. You may not be eligible to invest in every share class. Your financial intermediary may not make every share class available or may cease to make available one or more share classes of the Fund. The share class you select through your financial intermediary may have higher fees and/or sales charges than other classes of shares available through other financial intermediaries. An investor transacting in a class of Fund shares without any front-end sales charge, contingent deferred sales charge (CDSC), or other asset-based fee for sales or distribution, such as a Rule 12b-1 fee, may be required to pay a commission to the financial intermediary for effecting such transactions. Each investor’s personal situation is different and you may wish to discuss with your financial intermediary the share classes the Fund offers, which share classes are available to you and which share class(es) is/are appropriate for you. In all instances, it is your responsibility to notify your financial intermediary or (for Direct-at-Fund Accounts, as

Prospectus 2022 49

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defined below) the Fund at the time of purchase of any relationship or other facts that may qualify you for sales charge waivers or discounts. The Fund, the Distributor and the Transfer Agent do not provide investment advice or make recommendations regarding Fund share classes. Your financial intermediary may provide advice and recommendations to you, such as which share class(es) is/are appropriate for you.

When deciding which class of shares to buy, you should consider, among other things:

■ The amount you plan to invest.

■ How long you intend to remain invested in the Fund.

■ The fees (e.g., sales charge or “load”) and expenses for each share class.

■ Whether you may be eligible for a reduction or waiver of sales charges when you buy or sell shares.

 FUNDamentals

Front-End Sales Charge Calculation

The front-end sales charge is calculated as a percentage of the offering price.

■ The net asset value (NAV) per share is the price of a share calculated by the Fund every business day.

■ The offering price per share is the NAV per share plus any front-end sales charge (or load) that applies.

The dollar amount of any applicable front-end sales charge is the difference between the offering price of the shares you buy and the NAV of those shares. To determine the front-end sales charge you will pay when you buy Class A shares, the Fund will add the amount of your investment to the value of your account (and any other accounts eligible for aggregation of which you or your financial intermediary notifies the Fund) and base the sales charge on the aggregate amount. For information on account value aggregation, sales charge waivers and other important information, see Choosing a Share Class — Reductions/Waivers of Sales Charges.

 FUNDamentals

Contingent Deferred Sales Charge

A contingent deferred sales charge (CDSC) is a sales charge applied at the time you sell your shares, unlike a front-end sales charge that is applied at the time of purchase. A CDSC can vary based on the length of time that you have held your shares. A CDSC is applied to the NAV at the time of your purchase or sale, whichever is lower, and will not be applied to any shares you receive through Fund distribution reinvestments or any amount that represents appreciation in the value of your shares. For purposes of calculating a CDSC, the start of the holding period is generally the first day of the month in which your purchase was made.

When you place an order to sell shares of a class that has a CDSC, the Fund will first redeem any shares that are not subject to a CDSC, followed by those you have held the longest. This means that if a CDSC is imposed, you cannot designate the individual shares being redeemed for U.S. federal income tax purposes. You should consult your tax advisor about the tax consequences of investing in the Fund. In certain circumstances, the CDSC may not apply. See Choosing a Share Class — Reductions/Waivers of Sales Charges for details.

Share Class Features

The following summarizes the primary features of Class A, Class Adv, Class C, Class Inst, Class Inst2, Class Inst3, and Class R shares.

Not all Funds offer every class of shares. The Fund offers the class(es) of shares set forth on the cover of this prospectus and may offer other share classes through a separate prospectus. Although certain share classes are generally closed to new and/or existing investors, information relating to these share classes is included in the table below because certain qualifying purchase orders are permitted, as described below.

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The sales charge reductions and waivers available to investors who purchase and hold their Fund shares through different financial intermediaries may vary. Appendix A describes financial intermediary-specific reductions and/or waiver policies. A shareholder transacting in Fund shares through a financial intermediary identified in Appendix A should carefully read the terms and conditions of Appendix A. A reduction and/or waiver that is specific to a particular financial intermediary is not available to Direct-at-Fund Accounts, as defined below, or through another financial intermediary. The information in Appendix A may be provided by, or compiled from or based on information provided by the financial intermediaries identified in Appendix A. To obtain additional information regarding any sales charge reduction and/or waiver described in Appendix A, and to ensure that you receive any such reductions or waivers that may be available to you, please consult your financial intermediary.

Share Class	Eligible Investors; Minimum Initial Investments; Conversion Features(a)	Front-End Sales Charges(b)	Contingent Deferred Sales Charges (CDSCs)(b)	Sales Charge Reductions/Waivers	Maximum Distribution and/or Service (12b-1) Fees(c)
Class A	Eligibility: Available to the general public for investment Minimum Initial Investment: $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts (as described below))	5.75% maximum, declining to 0.00% on investments of $1 million or more	CDSC on certain investments of between $1 million and $50 million redeemed within 18 months after purchase charged as follows: • 1.00% CDSC if redeemed within 12 months after purchase and • 0.50% CDSC if redeemed more than 12, but less than 18, months after purchase	Reductions: yes, see Choosing a Share Class — Reductions/Waivers of Sales Charges – Class A Shares Front-End Sales Charge Reductions Waivers: yes, on Fund distribution reinvestments. For additional waivers, see Choosing a Share Class — Reductions/Waivers of Sales Charges – Class A Shares Front-End Sales Charge Waivers, as well as Choosing a Share Class — CDSC Waivers – Class A and Class C Financial intermediary-specific waivers are also available, see Appendix A	Service Fee: 0.25%
Class Adv	Eligibility: Available only to (i) omnibus retirement plans, including self-directed brokerage accounts within omnibus retirement plans that clear through institutional no transaction fee (NTF) platforms; retirement plans; (ii) trust companies or similar institutions; (iii) broker-dealers, banks, trust companies and similar institutions that clear Fund share transactions for their client or customer investment advisory or similar accounts through designated financial intermediaries and their mutual fund trading platforms that have been granted specific written authorization from the Transfer Agent with respect to Class Adv eligibility apart from selling, servicing or similar agreements; (iv) 501(c)(3) charitable organizations; (v) 529 plans; (vi) health savings accounts; (vii) investors participating in a fee-based advisory program sponsored by a financial intermediary or other entity that is not compensated by the Fund for those services, other than payments for shareholder servicing or sub-accounting performed in place	None	None	N/A	None

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Share Class	Eligible Investors; Minimum Initial Investments; Conversion Features(a)	Front-End Sales Charges(b)	Contingent Deferred Sales Charges (CDSCs)(b)	Sales Charge Reductions/Waivers	Maximum Distribution and/or Service (12b-1) Fees(c)
	of the Transfer Agent; and (viii) commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Adv shares within such platform. Minimum Initial Investment: None, except in the case of (viii) above, which is $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts)
Class C	Eligibility: Available to the general public for investment Minimum Initial Investment: $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts) Conversion Feature: Yes. Effective April 1, 2021, Class C shares generally automatically convert to Class A shares of the same Fund in the month of or the month following the 8-year anniversary of the Class C shares purchase date. Prior to April 1, 2021, Class C shares generally automatically converted to Class A shares of the same Fund in the month of or the month following the 10-year anniversary of the Class C shares purchase date.(a)	None	1.00% on certain investments redeemed within one year of purchase	Waivers: yes, on Fund distribution reinvestments. For additional waivers, see Choosing a Share Class — CDSC Waivers – Class A and Class C Financial intermediary-specific CDSC waivers are also available, see Appendix A	Distribution Fee: 0.75% Service Fee: 0.25%
Class Inst	Eligibility: Available only to certain eligible investors, which are subject to different minimum investment requirements, ranging from $0 to $2,000, including investors who purchase Fund shares through commissionable brokerage platforms where the financial intermediary holds the shares in an omnibus account and, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst shares within such platform; closed to (i) accounts of financial intermediaries that clear Fund share transactions for their client or customer accounts through designated financial intermediaries and their mutual fund	None	None	N/A	None

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Share Class	Eligible Investors; Minimum Initial Investments; Conversion Features(a)	Front-End Sales Charges(b)	Contingent Deferred Sales Charges (CDSCs)(b)	Sales Charge Reductions/Waivers	Maximum Distribution and/or Service (12b-1) Fees(c)
	trading platforms that have been given specific written notice from the Transfer Agent of the termination of their eligibility for new purchases of Class Inst shares and (ii) omnibus group retirement plans, subject to certain exceptions(d) Minimum Initial Investment: See Eligibility above
Class Inst2	Eligibility: Available only to (i) certain registered investment advisers and family offices that clear Fund share transactions for their client or customer accounts through designated financial intermediaries and their mutual fund trading platforms that have been granted specific written authorization from the Transfer Agent with respect to Class Inst2 eligibility apart from selling, servicing or similar agreements; (ii) omnibus retirement plans(d); (iii) health savings accounts, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst2 shares within such platform and that Fund shares are held in an omnibus account; and (iv) institutional investors that are clients of the Columbia Threadneedle Global Institutional Distribution Team that invest in Class Inst2 shares for their own account through platforms approved by the Distributor or an affiliate thereof to offer and/or service Class Inst2 shares within such platform. Minimum Initial Investment: None	None	None	N/A	None
Class Inst3	Eligibility: Available to: (i) group retirement plans that maintain plan-level or omnibus accounts with the Fund(d); (ii) institutional investors that are clients of the Columbia Threadneedle Global Institutional Distribution Team that invest in Class Inst3 shares for their own account through platforms approved by the Distributor or an affiliate thereof to offer and/or service Class Inst3 shares within such platform; (iii) collective trust funds; (iv) affiliated or unaffiliated mutual funds (e.g., funds operating as funds-of-funds); (v) fee-based platforms of financial intermediaries (or the clearing intermediary they trade through) that have an agreement with the	None	None	N/A	None

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Choosing a Share Class (continued)

Share Class	Eligible Investors; Minimum Initial Investments; Conversion Features(a)	Front-End Sales Charges(b)	Contingent Deferred Sales Charges (CDSCs)(b)	Sales Charge Reductions/Waivers	Maximum Distribution and/or Service (12b-1) Fees(c)
	Distributor or an affiliate thereof that specifically authorizes the financial intermediary to offer and/or service Class Inst3 shares within such platform, provided also that Fund shares are held in an omnibus account; (vi) commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst3 shares within such platform and that Fund shares are held in an omnibus account; (vii) health savings accounts, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst3 shares within such platform and that Fund shares are held in an omnibus account; and (viii) bank trust departments, subject to an agreement with the Distributor that specifically authorizes offering Class Inst3 shares and provided that Fund shares are held in an omnibus account. In each case above where noted that Fund shares are required to be held in an omnibus account, the Distributor, may, in its discretion, determine to waive this requirement. Minimum Initial Investment: No minimum for the eligible investors described in (i), (iii), (iv) and (v) above; $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts) for the eligible investors described in (vi) above; and $1 million for all other eligible investors, unless waived in the discretion of the Distributor
Class R	Eligibility: Available only to eligible retirement plans, health savings accounts and, in the sole discretion of the Distributor, other types of retirement accounts held through platforms maintained by financial intermediaries approved by the Distributor Minimum Initial Investment: None	None	None	N/A	Distribution Fee: 0.50%

(a) For more information on the conversion of Class C shares to Class A shares, see Choosing a Share Class — Sales Charges and Commissions — Class C Shares —Conversion to Class A Shares.

(b) For more information on applicable sales charges, see Choosing a Share Class — Sales Charges and Commissions, and for information about certain exceptions to these sales charges, see Choosing a Share Class — Reductions/Waivers of Sales Charges.

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(c) These are the maximum applicable distribution and/or service fees under the Fund’s Rule 12b-1 plan. Because these fees are paid out of Fund assets on an ongoing basis, over time these fees will increase the cost of your investment and may cost you more than paying other types of distribution and/or service fees. For more information on distribution and service fees, see Choosing a Share Class — Distribution and Service Fees.

(d) These share classes are closed to new accounts generally or to new accounts of certain categories of investors, subject to certain conditions, as summarized below and described in more detail under Buying, Selling and Exchanging Shares — Buying Shares — Eligible Investors:

•  Class Inst Shares: Financial intermediaries that clear Fund share transactions through designated financial intermediaries and their mutual fund trading platforms that were given specific written notice from the Transfer Agent of the termination, effective March 29, 2013, of their eligibility for new purchases of Class Inst shares and omnibus retirement plans are not permitted to establish new Class Inst accounts, subject to certain exceptions. Omnibus retirement plans that opened and, subject to exceptions, funded a Class Inst account as of close of business on March 28, 2013, and have continuously held Class Inst shares in such account after such date, may generally continue to make additional purchases of Class Inst shares, open new Class Inst accounts and add new participants. In certain circumstances and in the sole discretion of the Distributor, omnibus retirement plans affiliated with a grandfathered plan may also open new Class Inst accounts. Accounts of financial intermediaries (other than omnibus retirement plans) that clear Fund share transactions for their client or customer accounts through designated financial intermediaries and their mutual fund trading platforms are not permitted to establish new Class Inst accounts or make additional purchases of Class Inst shares (other than through reinvestment of distributions).

•  Class Inst2 Shares. Shareholders with Class Inst2 accounts funded before November 8, 2012 who do not satisfy the current eligibility criteria for Class Inst2 shares may not establish new Class Inst2 accounts but may continue to make additional purchases of Class Inst2 shares in existing accounts. In addition, investment advisory programs and similar programs that opened a Class Inst2 account as of May 1, 2010, and continuously hold Class Inst2 shares in such account after such date, may generally not only continue to make additional purchases of Class Inst2 shares but also open new Class Inst2 accounts and add new shareholders in the program.

•  Class Inst3 Shares: Shareholders with Class Inst3 accounts funded before November 8, 2012 who do not satisfy the current eligibility criteria for Class Inst3 shares may not establish new accounts for such share class but may continue to make additional purchases of Class Inst3 shares in existing accounts.

Sales Charges and Commissions

Sales charges, commissions, and distribution fees compensate financial intermediaries (typically your financial advisor) for selling shares to you, and service fees compensate financial intermediaries for maintaining and servicing the shares held in your account with them. Distribution and service fees are discussed in a separate sub-section below. Depending on which share class you choose and the financial intermediary through which you purchase your shares, you may pay these charges at potentially different levels at the outset as a front-end sales charge, at the time you sell your shares as a CDSC and/or over time in the form of distribution and/or service fees. You may be required to pay brokerage commissions and other fees to financial intermediaries when transacting in any class of Fund shares, including those that do not assess any front-end sales charge, contingent deferred sales charge, or other asset-based fee for sales or distribution. Such brokerage commissions and other fees are set by the financial intermediary.

As described in more detail below, Class A shares have a front-end sales charge, which is deducted from your purchase price when you buy your shares, and results in a smaller dollar amount being invested in the Fund than the purchase price you pay (unless you qualify for a waiver or reduction of the sales charge). The Fund’s other share classes do not have a front-end sales charge, so the full amount of your purchase price is invested in those classes. Class A shares have lower ongoing distribution and/or service fees than Class C and Class R shares of the Fund. Over time, Class C and Class R shares can incur distribution and/or service fees that are equal to or more than the front-end sales charge and the distribution and/or service fees you would pay for Class A shares. Although the full amount of your purchase price of Class C and Class R shares is invested in a Fund, your return on this money will be reduced by the expected higher annual expenses of Class C and Class R shares. In this regard, note that effective April 1, 2021, Class C shares will generally automatically convert to Class A shares of the same Fund in the month of or the month following the 8-year anniversary of the Class C shares purchase date (prior to April 1, 2021, the 10-year anniversary of such date). The Fund may convert Class C shares held through a financial intermediary to Class A shares sooner in connection with the withdrawal of Class C shares of the Fund from the financial intermediary’s platform or accounts. No sales charge or other charges will apply in connection with such conversions, and the conversions are free from U.S. federal income tax. Once your Class C shares convert to Class A shares, your total returns from an investment in the Fund may increase as a result of the lower operating costs of Class A shares. Class Adv, Class Inst, Class Inst2 and Class Inst3 shares of the Fund do not have distribution and/or service fees.

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Whether the ultimate cost is higher for one share class over another depends on the amount you invest, how long you hold your shares, the fees (i.e., sales charges) and expenses of the class and whether you are eligible for reduced or waived sales charges, if available. You are responsible for choosing the share class most appropriate for you after taking into account your share class eligibility, class-specific features, and any applicable reductions in, or waivers of, sales charges. For more information, see Choosing a Share Class – Reductions/Waivers of Sales Charges. We encourage you to consult with a financial advisor who can help you with your investment decisions. Please contact your financial intermediary for more information about services, fees and expenses, and other important information about investing in the Fund, as well as with any questions you may have about your investing options. In all instances, it is your responsibility to notify your financial intermediary or (for Direct-at-Fund Accounts, as defined below) the Fund at the time of purchase of any relationship or other facts that may qualify you for sales charge waivers or discounts.

Class A Shares — Front-End Sales Charge

Unless your purchase qualifies for a waiver (e.g., you buy the shares through reinvested Fund dividends or distributions or subject to an applicable financial intermediary-specific waiver), you will pay a front-end sales charge when you buy Class A shares, resulting in a smaller dollar amount being invested in a Fund than the purchase price you pay. The Class A shares sales charge is waived on Class C shares converted to Class A shares. For more information about sales charge waivers and reduction opportunities, see Choosing a Share Class — Reductions/Waivers of Sales Charges and Appendix A.

The Distributor receives the sales charge and re-allows (or pays) a portion of the sales charge to the financial intermediary through which you purchased the shares. The Distributor retains the balance of the sales charge.

The front-end sales charge you will pay on Class A shares:

■ depends on the amount you are investing (generally, the larger the investment, the smaller the percentage sales charge), and

■ is based on the total amount of your purchase and the value of your account (and any other accounts eligible for aggregation of which you or your financial intermediary notifies the Fund).

The table below presents the front-end sales charge as a percentage of both the offering price and the net amount invested.

Class A Shares — Front-End Sales Charge — Breakpoint Schedule
Breakpoint Schedule For:	Dollar amount of shares bought(a)	Sales charge as a % of the offering price(b)	Sales charge as a % of the net amount invested(b)	Amount retained by or paid to financial intermediaries as a % of the offering price
Class A Shares	$0–$49,999	5.75%	6.10%	5.00%
	$50,000–$99,999	4.50%	4.71%	3.75%
	$100,000–$249,999	3.50%	3.63%	3.00%
	$250,000–$499,999	2.50%	2.56%	2.15%
	$500,000–$999,999	2.00%	2.04%	1.75%
	$1,000,000 or more	0.00%	0.00%	0.00%(c)

(a) Purchase amounts and account values may be aggregated among all eligible Fund accounts for the purposes of this table. See Choosing a Share Class — Reductions/Waivers of Sales Charges for a discussion of account value aggregation.

(b) Because the offering price is calculated to two decimal places, the dollar amount of the sales charge as a percentage of the offering price and your net amount invested for any particular purchase of Fund shares may be higher or lower depending on whether downward or upward rounding was required during the calculation process. Purchase price includes the sales charge.

(c) For information regarding cumulative commissions paid to your financial intermediary when you buy $1 million or more of Class A shares of a Fund, see Class A Shares — Commissions below.

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Class A Shares — CDSC

In some cases, you'll pay a CDSC if you sell Class A shares that you purchased without a front-end sales charge.

■ If you purchased Class A shares without an initial sales charge because your accounts aggregated between $1 million and $50 million at the time of purchase, you will incur a CDSC if you redeem those shares within 18 months after purchase, which is charged as follows: 1.00% CDSC if shares are redeemed within 12 months after purchase; and 0.50% CDSC if shares are redeemed more than 12, but less than 18, months after purchase.

■ Subsequent Class A share purchases that bring your aggregate account value to $1 million or more (but less than $50 million) will also be subject to a CDSC if you redeem them within the time periods noted above.

Class A Shares — Commissions

The Distributor may pay your financial intermediary an up-front commission when you buy Class A shares. The Distributor generally funds the commission through the applicable sales charge you paid. For more information, see Class A Shares — Front-End Sales Charge above.

The Distributor may also pay your financial intermediary a cumulative commission when you buy Class A shares in amounts not subject to a front-end sales charge, according to the following schedules (assets initially purchased into Class A shares of Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund and Columbia U.S. Treasury Index Fund that were purchased without the application of a front-end sales charge are excluded for purposes of calculating a financial intermediary’s commission under these schedules):

Class A Shares — Commission Schedule (Paid by the Distributor to Financial Intermediaries)
Purchase Amount	Commission Level* (as a % of net asset value per share)
$1 million – $2,999,999	1.00%
$3 million – $49,999,999	0.50%
$50 million or more	0.25%

* The commission level applies to the applicable asset level; therefore, for example, for a purchase of $5 million, the Distributor would pay a commission of 1.00% on the first $2,999,999 and 0.50% on the balance.

Class C Shares — Front-End Sales Charge

You do not pay a front-end sales charge when you buy Class C shares, but you may pay a CDSC when you sell Class C shares. Although Class C shares do not have a front-end sales charge, over time Class C shares can incur distribution and/or service fees that are equal to or more than the front-end sales charge and distribution and/or service fees you would pay for Class A shares. Thus, although the full amount of your purchase of Class C shares is invested in a Fund, any positive investment return on this money may be partially or fully offset by the expected higher annual expenses of Class C shares.

Class C Shares — Conversion to Class A Shares

Effective April 1, 2021, Class C shares of a Fund generally automatically convert to Class A shares of the same Fund in the month of or the month following the 8-year anniversary of the Class C shares purchase date. Prior to April 1, 2021, Class C shares of a Fund generally automatically converted to Class A shares of the same Fund in the month of or in the month following the 10-year anniversary of the Class C shares purchase date. Class C shares held through a financial intermediary in an omnibus account will be converted (pursuant to the financial intermediary’s Class C conversion policy, including those disclosed in Appendix A, which may differ from the Fund’s policy described here) provided that the intermediary is able to track individual shareholders’ holding periods. It is the financial intermediary's (and not the Fund's) responsibility to keep records and to ensure that the shareholder holding period is calculated properly. Not all financial intermediaries are able to track individual shareholders' holding periods. For example, group retirement plans held through third-party intermediaries that hold Class C shares in an omnibus account may not track participant level share lot aging. Please consult with your financial intermediary about your

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eligibility for Class C share conversion. The Fund may convert Class C shares held through a financial intermediary to Class A shares sooner in connection with the withdrawal of Class C shares of the Fund from the financial intermediary's platform or accounts. Once your Class C shares convert to Class A shares, your total returns from an investment in the Fund may increase as a result of the lower operating costs of Class A shares.

The following rules apply to the automatic conversion of Class C shares to Class A shares:

■ Class C share accounts that are Direct-at-Fund Accounts and Networked Accounts for which the Transfer Agent (and not your financial intermediary) sends you Fund account transaction confirmations and statements, convert on or about the 15th day of the month (if the 15th is not a business day, then the next business day thereafter) that they become eligible for automatic conversion provided that the Fund has records that Class C shares have been held for the requisite time period.

■ For purposes of determining the month when your Class C shares are eligible for conversion, the start of the holding period is the first day of the month in which your purchase was made. Your financial intermediary may choose a different day of the month to convert Class C shares. Please contact your financial intermediary for more information on calculating the holding period.

■ Any shares you received from reinvested distributions on these shares generally will convert to Class A shares at the same time.

■ You’ll receive the same dollar value of Class A shares as the Class C shares that were automatically converted. Class C shares that you received from an exchange of Class C shares of another Fund will convert based on the day you bought the original shares.

■ In addition to the above automatic conversion of Class C to Class A shares policy, the Transfer Agent seeks to convert Class C shares as soon as administratively feasible, regardless of how long such shares have been owned, to Class A shares of the same Fund for Direct-at-Fund Accounts (as defined below) that do not or no longer have a financial intermediary assigned to them. Direct-at-Fund Accounts that do not have a financial intermediary assigned to them are not permitted to purchase Class C shares; Class C share purchase orders received by Direct-at-Fund Accounts that do not have a financial intermediary assigned to the account will automatically be invested in Class A shares of the same Fund.

■ No sales charge or other charges apply in connection with these automatic conversions, and the conversions are free from U.S. federal income tax.

Class C Shares — CDSC

You will pay a CDSC of 1.00% if you redeem Class C shares within 12 months of buying them unless you qualify for a waiver of the CDSC (e.g., the shares you are selling were purchased with reinvested Fund distributions). Redemptions of Class C shares are not subject to a CDSC if redeemed after 12 months. For more information, see Choosing a Share Class — Reductions/Waivers of Sales Charges.

Class C Shares — Commissions

Although there is no front-end sales charge when you buy Class C shares, the Distributor makes an up-front payment (which includes a sales commission and an advance of service fees) directly to your financial intermediary of up to 1.00% of the NAV per share when you buy Class C shares. A portion of this payment may be passed along to your financial advisor. The Distributor seeks to recover this payment through distribution fees of up to 0.75% and shareholder service fees of up to 0.25% it receives under the Fund's Rule 12b-1 plan during the first 12 months following the sale of Class C shares, and any applicable CDSC when you sell your shares. For more information, see Choosing a Share Class — Distribution and Service Fees.

Reductions/Waivers of Sales Charges

The availability of certain sales charge waivers and discounts will depend on whether you purchase your shares directly from the Fund (i.e., a Direct-at-Fund Account, as defined below) or through a financial intermediary. Financial intermediaries may have different policies and procedures regarding the availability of front-end sales charge and/or CDSC waivers. In all instances, it is your responsibility to notify your financial intermediary or (for Direct-at-Fund

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Accounts, as defined below) the Fund at the time of purchase of any relationship or other facts that may qualify you for sales charge waivers or discounts. In order to obtain waivers and discounts not available through a particular financial intermediary, shareholders will have to purchase Fund shares directly from the Fund (if permitted) or through a different financial intermediary. For a description of financial intermediary-specific sales charge reductions and/or waivers, see Appendix A.

Class A Shares Front-End Sales Charge Reductions

The Fund makes available two means of reducing the front-end sales charge that you may pay when you buy Class A shares of a Fund. These types of sales charge reductions are also referred to as breakpoint discounts.

First, through the right of accumulation (ROA), you may combine the value of eligible accounts (as described in the Eligible Accounts section below) maintained by you and members of your immediate family to reach a breakpoint discount level and apply a lower front-end sales charge to your purchase. To calculate the combined value of your eligible Fund accounts in the particular class of shares, the Fund will use the current public offering price per share. For purposes of obtaining a breakpoint discount through ROA, you may aggregate your and your “immediate family” members' ownership (as described in the FUNDamentals box below) of certain classes of shares held in certain account types, as described in the Eligible Accounts section below.

Second, by making a statement of intent to purchase additional shares (commonly referred to as a letter of intent (LOI)), you may pay a lower sales charge on all purchases of Class A shares made within 13 months after the date of your LOI. Your LOI must state the aggregate amount of purchases you intend to make in that 13-month period, which must be at least enough to reach the first (or next) breakpoint of the Fund. The required form of LOI may vary by financial intermediary, so please contact them directly for more information. Five percent of the purchase commitment amount will be placed in escrow. At the end of the 13-month period, the shares will be released from escrow, provided that you have invested the commitment amount. If you do not invest the commitment amount by the end of the 13 months, the remaining amount of the unpaid sales charge will be redeemed from the escrowed shares and the remaining balance released from escrow. To calculate the total value of the purchases you've made under an LOI, the Fund will use the historic cost (i.e., dollars invested and not current market value) of the shares held in each eligible account; reinvested dividends or capital gains, or purchases made through the reinstatement privilege do not count as purchases made under an LOI. For purposes of making an LOI to purchase additional shares, you may aggregate eligible shares owned by you or your immediate family members in eligible accounts, valued as of the day immediately before the initiation of your LOI.

You must request the reduced sales charge (whether through ROA or an LOI) when you buy shares. If you do not complete and file an LOI, or do not request the reduced sales charge at the time of purchase, you will not be eligible for the reduced sales charge. To obtain a breakpoint discount, you must notify your financial intermediary in writing at the time you buy your shares of each eligible account maintained by you and members of your immediate family, including accounts maintained through different financial intermediaries. You and your financial intermediary are responsible for ensuring that you receive discounts for which you are eligible. Please contact your financial intermediary with questions regarding application of the eligible discount to your account. You may be asked by your financial intermediary (or by the Fund if you hold your account directly with the Fund) for account statements or other records to verify your discount eligibility for new and subsequent purchases, including, when applicable, records for accounts opened with a different financial intermediary and records of accounts established by members of your immediate family.

The sales charge reductions available to investors who purchase and hold their Fund shares through different financial intermediaries may vary. For a description of such financial intermediary-specific sales charge reductions, see Appendix A.

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 FUNDamentals

Your “Immediate Family” and Account Value Aggregation

For purposes of obtaining a breakpoint discount for Class A shares, the value of your account will be deemed to include the value of all applicable shares in eligible Fund accounts that are held by you and your “immediate family,” which includes your spouse, domestic partner, parent, step-parent, legal guardian, child under 21, step-child under 21, father-in-law and mother-in-law, provided that you and your immediate family members share the same mailing address. Any Fund accounts linked together for account value aggregation purposes as of the close of business on September 3, 2010 will be permitted to remain linked together. Group retirement plan accounts are valued at the retirement plan level.

Eligible Accounts

The following accounts are eligible for account value aggregation as described above, provided that they are invested in Class A (excluding, in the case of Direct-at-Fund Accounts, Funds that do not assess a front-end sales charge, including Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund and Columbia U.S. Treasury Index Fund, unless such shares were purchased via an exchange from Class A shares of a Fund on which you paid the Class A share applicable front-end sales charge), Class C, Class E, Class Inst or Class V shares of a Fund, or non-retirement plan accounts invested in Class Adv, Class Inst2 or Class Inst3 shares of a Fund: individual or joint accounts; Roth and traditional Individual Retirement Accounts (IRAs); Simplified Employee Pension accounts (SEPs), Savings Investment Match Plans for Employees of Small Employers accounts (SIMPLEs) and Tax Sheltered Custodial Accounts (TSCAs); Uniform Gifts to Minors Act (UGMA)/Uniform Transfers to Minors Act (UTMA) accounts for which you, your spouse, or your domestic partner is parent or guardian of the minor child; revocable trust accounts for which you or an immediate family member, individually, is the beneficial owner/grantor; accounts held in the name of your, your spouse’s, or your domestic partner’s sole proprietorship or single owner limited liability company or S corporation; qualified retirement plan assets, provided that you are the sole owner of the business sponsoring the plan, are the sole participant (other than a spouse) in the plan, and have no intention of adding participants to the plan; and investments in wrap accounts.

The following accounts are not eligible for account value aggregation as described above: accounts of pension and retirement plans with multiple participants, such as 401(k) plans (which are combined to reduce the sales charge for the entire pension or retirement plan and therefore are not used to reduce the sales charge for your individual accounts); investments in 529 plans, donor advised funds, variable annuities, variable insurance products or managed separate accounts; charitable and irrevocable trust accounts; accounts holding shares of money market funds that used the Columbia brand before May 1, 2010; accounts invested in Class R shares of a Fund; and retirement plan accounts invested in Class Adv, Class Inst2 or Class Inst3 shares of a Fund.

Additionally, direct purchases of shares of Columbia Government Money Market Fund may not be aggregated for account value aggregation purposes; however, shares of Columbia Government Money Market Fund acquired by exchange from other Columbia Funds that assess a sales charge may be included in account value aggregation.

Class A Shares Front-End Sales Charge Waivers

There are no front-end sales charges on reinvested Fund distributions. The Class A shares sales charge is waived on conversions of Class C shares to Class A shares. The Distributor may waive front-end sales charges on purchases of Class A shares of the Funds by certain categories of investors, including Board members, certain employees of financial intermediaries, Fund portfolio managers, certain partners and employees of outside legal counsel to the Funds or the Board, separate accounts of an insurance company exempt from registration as an investment company under Section 3(c)(11) of the 1940 Act, registered broker-dealer firms that have an agreement with the Distributor purchasing Fund shares for their investment account only, and qualified employee benefit plan rollovers to Class A

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shares in the same Fund (see Appendix S to the SAI for details). For a more complete description of categories of investors who may purchase Class A shares of the Funds at NAV, without payment of any front-end sales charge that would otherwise apply, see Appendix S to the SAI.

In addition, certain types of purchases of Class A shares may be made at NAV. The Distributor may waive front-end sales charges on (i) purchases (including exchanges) of Class A shares in accounts of financial intermediaries that have entered into agreements with the Distributor to offer Fund shares to self-directed investment brokerage accounts that may or may not charge a transaction fee to customers; (ii) exchanges of Class Inst shares of a Fund for Class A shares of the Fund; (iii) purchases of Class A shares on brokerage mutual fund-only platforms of financial intermediaries that have an agreement with the Distributor that specifically authorizes the offering of Class A shares within such platform; (iv) purchases through certain wrap fee or other products or programs that involve fee-based compensation arrangements that have, or clear trades through a financial intermediary that has, a selling agreement with the Distributor; (v) purchases through state sponsored 529 Plans; (vi) purchases through banks, trust companies, and thrift institutions acting as fiduciaries; (vii) purchases through certain employee benefit plans and certain qualified deferred compensation plans; and (viii) purchases of Class A shares in Direct-at-Fund Accounts (as defined below) that do not have a financial intermediary assigned to them. For a more complete description of these eligible transactions, see Appendix S to the SAI.

The sales charge waivers available to investors who purchase and hold their Fund shares through different financial intermediaries may vary. For a description of such financial intermediary-specific sales charge waivers, see Appendix A.

CDSC Waivers – Class A and Class C

You may be able to avoid an otherwise applicable CDSC when you sell Class A or Class C shares of the Fund. This could happen because of the way in which you originally invested in the Fund, because of your relationship with the Funds or for other reasons. For example, the CDSC will be waived on redemptions of shares: in the event of the shareholder's death; for which no sales commission or transaction fee was paid to an authorized financial intermediary at the time of purchase; purchased through reinvestment of dividends and capital gain distributions; that result from required minimum distributions taken from retirement accounts due to the shareholder reaching the qualified age based on applicable IRS regulations; that result from returns of excess contributions made to retirement plans or individual retirement accounts (subject to certain conditions); initially purchased by an employee benefit plan (for Class A shares) and that are not connected with a plan level termination (for Class C shares); in connection with the Fund's Small Account Policy (which is described in Buying, Selling and Exchanging Shares — Transaction Rules and Policies); held within Direct-at-Fund Accounts that do not have a financial intermediary assigned to them; and by certain other investors and in certain other types of transactions or situations. Restrictions may apply to certain accounts and certain transactions. The Distributor may, in its sole discretion, authorize the waiver of the CDSC for additional classes of investors. The Fund may change or cancel these terms at any time. Any change or cancellation applies only to future purchases. For a more complete description of the available waivers of the CDSC on redemptions of Class A or Class C shares, see Appendix S to the SAI.

The sales charge waivers available to investors who purchase and hold their Fund shares through different financial intermediaries may vary. For a description of such financial intermediary-specific sales charge waivers, see Appendix A.

Repurchases (Reinstatements)

As noted in the table below, you can redeem shares of certain classes (see Redeemed Share Class below) and use such redemption proceeds to buy shares of the Corresponding Repurchase Class without paying an otherwise applicable sales charge and/or CDSC (other than, in the case of Direct-at-Fund Accounts, redemptions from Funds that do not assess a front-end sales charge, including Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund and Columbia U.S. Treasury Index Fund, unless such shares were purchased via an exchange from Class A shares of a Fund on which you paid the Class A share applicable front-end sales charge) within 90 days, up to the amount of the redemption proceeds.

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Repurchases (Reinstatements)
Redeemed Share Class	Corresponding Repurchase Class
Class A	Class A
Class C	Class C

Any CDSC paid upon redemption of your Class A or Class C shares of a Fund will not be reimbursed.

To be eligible for the repurchase (or reinstatement) privilege, the purchase must be made into an account for the same owner, but does not need to be into the same Fund from which the shares were sold. The Transfer Agent, Distributor or their agents must receive a written reinstatement request from you or your financial intermediary within 90 days after the shares are redeemed. The purchase of the Corresponding Repurchase Class (as noted in the table above) through this repurchase (or reinstatement) privilege will be made at the NAV of such shares next calculated after the request is received in “good form.” Systematic withdrawals and purchases are excluded from this policy.

Restrictions and Changes in Terms and Conditions

Restrictions may apply to certain accounts and certain transactions. The Funds and/or the Distributor may change or cancel these terms and conditions at any time. Unless you provide your financial intermediary with information in writing about all of the factors that may count toward available reductions or waivers of an applicable sales charge, there can be no assurance that you will receive all of the reductions and waivers for which you may be eligible. To the extent your Fund account is held directly with the Fund, you should provide this information to the Fund when placing your purchase or redemption order. Please see Appendix A to this prospectus and Appendix S of the SAI for more information about sales charge waivers.

Distribution and Service Fees

The Board has approved, and the Columbia Acorn Funds have adopted, a distribution plan pursuant to Rule 12b-1 under the 1940 Act that sets the distribution and/or service fees that are periodically deducted from the Funds’ assets. These fees are calculated daily, may vary by share class and are intended to compensate the Distributor and/or eligible financial intermediaries for, with regard to distribution fees, selling Fund shares and, with regard to service fees, directly or indirectly providing services to shareholders. Because the fees are paid out of the Fund's assets on an ongoing basis, they will increase the cost of your investment over time.

The table below shows the maximum annual distribution and/or service fees (as an annual percentage of average daily net assets) and the combined amount of such fees applicable to each share class of the Columbia Acorn Funds:

	Distribution Fee	Service Fee	Combined Total
Class A	None	0.25%	0.25%
Class Adv	None	None	None
Class C	0.75%	0.25%	1.00%
Class Inst	None	None	None
Class Inst2	None	None	None
Class Inst3	None	None	None
Class R	0.50%	None	0.50%

The distribution and/or service fees for Class A, Class C, and Class R shares, as applicable, are subject to the requirements of Rule 12b-1 under the 1940 Act. The Distributor may retain these fees otherwise payable to financial intermediaries if the amounts due are below an amount determined by the Distributor in its sole discretion.

For Class A shares, the Distributor begins to pay these fees immediately after purchase, except in the following case, in which the Distributor begins to pay these fees 12 months after purchase: a purchase of Class A shares of $1 million or more that pay a Class A up-front commission to your financial intermediary and the financial intermediary has opted to receive such commission. The Distributor’s policy to otherwise begin to pay these fees immediately on

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Class A shares also applies to purchases of funds that do not pay an up-front sales commission on Class A shares, which includes Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund and Columbia U.S. Treasury Index Fund. For Class C shares, the Distributor begins to pay these fees 12 months after purchase. However, for Class C shares, financial intermediaries may opt to decline the up-front payment described in Choosing a Share Class – Sales Charges and Commissions – Class C Shares – Commissions and instead may receive these fees immediately after purchase. If the intermediary opts to receive the up-front payment, the Distributor retains the distribution and service fee for the first 12 months following the sale of Class C shares in order to recover the up-front payment made to financial intermediaries and to pay for other related expenses. For Class R shares, the Distributor begins to pay these fees immediately after purchase.

If you maintain shares of the Fund directly with the Fund, without working with a financial advisor or other financial intermediary, distribution and service fees may be retained by the Distributor as payment or reimbursement for incurring certain distribution and shareholder service related expenses.

Over time, these distribution and/or service fees will reduce the return on your investment and may cost you more than paying other types of sales charges. The Fund will pay these fees to the Distributor and/or to eligible financial intermediaries for as long as the distribution plan continues in effect, which is expected to be indefinitely. However, the Fund may reduce or discontinue payments at any time. Your financial intermediary may also charge you other additional fees for providing services to your account, which may be different from those described here.

Financial Intermediary Compensation

The Distributor, the Investment Manager and their affiliates make payments, from their own resources, to financial intermediaries, including other Ameriprise Financial affiliates, for marketing/sales support services relating to the Funds (Marketing Support Payments). Such payments are generally based upon one or more of the following factors: average net assets of the Funds attributable to that financial intermediary; gross sales of the Funds attributable to that financial intermediary; reimbursement of ticket charges (fees that a financial intermediary charges its representatives for effecting transactions in Fund shares); or a negotiated lump sum payment. While the financial arrangements may vary for each financial intermediary, Marketing Support Payments to any one financial intermediary are generally between 0.01% and 0.40% on an annual basis for payments based on average net assets of the Fund attributable to the financial intermediary, and between 0.05% and 0.25% on an annual basis for firms receiving a payment based on gross sales of the Funds attributable to the financial intermediary. The Distributor, the Investment Manager and their affiliates make payments with respect to a Fund or the Columbia Funds generally on a basis other than those described above or in larger amounts when dealing with certain financial intermediaries. Not all financial intermediaries receive Marketing Support Payments. The Distributor, the Investment Manager and their affiliates do not make Marketing Support Payments with respect to Class Inst3 shares of the Columbia Acorn Funds.

In addition, the Transfer Agent has certain arrangements in place to compensate financial intermediaries, including other Ameriprise Financial affiliates, that hold Fund shares through networked and omnibus accounts, including omnibus retirement plans, for services that they provide to beneficial Fund shareholders (Shareholder Services). Shareholder Services and related fees vary by financial intermediary and according to distribution channel and may include sub-accounting, sub-transfer agency, participant recordkeeping, shareholder or participant reporting, shareholder or participant transaction processing, maintenance of shareholder records, preparation of account statements and provision of customer service, and are not intended to include services that are primarily intended to result in the sale of Fund shares. Payments for Shareholder Services vary by financial intermediary and according to distribution channel, but generally are not expected, with certain limited exceptions, to exceed 0.40% of the average aggregate value of the Fund’s shares. Payments to financial intermediaries in excess of the amounts paid by the Fund are borne by the Distributor, the Investment Manager and/or their affiliates.

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Choosing a Share Class (continued)

Generally, each Fund in the Columbia Acorn Family of Funds compensates the Transfer Agent for payments made for Shareholder Services, for each share class except Class Inst3. Effective July 1, 2017, the Columbia Acorn Funds compensate the Transfer Agent for payments made for Shareholder Services as follows:

Financial Intermediary Distribution Channel	Fee Rate
Retirement	up to 0.18% of Fund assets held by intermediaries or platforms charging an asset-based fee, or $18 per account held by intermediaries or platforms charging a per account fee
Fund supermarket transaction fee (TF)	up to 0.12% of Fund assets held by intermediaries or platforms charging an asset-based fee, or $16 per account held for intermediaries or platforms charging a per account fee
Fund supermarket no-transaction fee (NTF)	up to 0.18% of Fund assets held by intermediaries or platforms charging an asset-based fee, or $18 per account held by intermediaries or platforms charging a per account fee
Bank	up to 0.10% of Fund assets held by intermediaries or platforms charging an asset-based fee, or $20 per account held by intermediaries or platforms charging a per account fee
Broker-dealer	up to 0.13% of Fund assets held by intermediaries or platforms charging an asset-based fee, or $16 per account held by intermediaries or platforms charging a per account fee

With respect to Class Inst2 and Class Inst3 shares of the Fund, total annual compensation payable to the Transfer Agent may not exceed, respectively, 0.07% and 0.02% of the average daily net assets of the Class. For additional details about the application of the Columbia Acorn Funds’ fee limits, please refer to the SAI.

The Transfer Agent does not pay financial intermediaries for Shareholder Services, and the Fund does not compensate the Transfer Agent for any Shareholder Services provided by financial intermediaries with respect to Class Inst3 shares of the Columbia Acorn Funds. The Fund believes that the fee levels paid to the Transfer Agent are reasonably related to the Shareholder Services provided, but payments may vary and there can be no assurance that the Fund will be able to identify with specificity the costs or particular Shareholder Services for which compensation is paid.

In addition to the payments described above, the Distributor, the Investment Manager and their affiliates typically make other payments or allow promotional incentives to certain broker-dealers to the extent permitted by the Securities and Exchange Commission (the SEC) and Financial Industry Regulatory Authority (FINRA) rules and by other applicable laws and regulations.

Amounts paid by the Distributor, the Investment Manager and their affiliates are paid out of their own resources and do not increase the amount paid by you or the Fund. You can find further details in the SAI about the payments made by the Distributor, the Investment Manager and their affiliates, as well as a list of the financial intermediaries, including Ameriprise Financial affiliates, to which the Distributor and the Investment Manager have agreed to make Marketing Support Payments and pay Shareholder Services fees.

Your financial intermediary may charge you fees and commissions in addition to those described in this prospectus. You should consult with your financial intermediary and review carefully any disclosure your financial intermediary provides regarding its services and compensation. Depending on the financial arrangement in place at any particular time, a financial intermediary and its financial advisors may have a conflict of interest or financial incentive for recommending the Fund or a particular share class over others.

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Buying, Selling and Exchanging Shares

Share Price Determination

The price you pay or receive when you buy, sell or exchange shares is the Fund's next determined net asset value (or NAV) per share for a given share class. The Fund calculates the NAV per share for each class of shares of the Fund at the end of each business day, with the value of the Fund's shares based on the total value of all of the securities and other assets that it holds as of such specified time. Any affiliated underlying funds calculate their NAV in the same manner as the Fund calculates its NAV.

 FUNDamentals

NAV Calculation

Each of the Fund's share classes calculates its NAV per share as follows:

NAV per share =  (Value of assets of the share class) – (Liabilities of the share class)
Number of outstanding shares of the class

 FUNDamentals

Business Days

A business day is any day that the New York Stock Exchange (NYSE) is open. A business day ends at (i) the scheduled close of the NYSE for such day (usually 4:00 p.m. Eastern Time or such other time as the NYSE may schedule), (ii) the scheduled close of the NYSE (usually 4:00 p.m. Eastern Time) on any business day on which the NYSE has an unscheduled close or intraday trading halt or other disruption, regardless of the time of such unscheduled close, halt or disruption or whether trading resumes, or (iii) such other time as the Board may from time to time determine. On holidays and other days when the NYSE is closed, the Fund’s NAV is not calculated and the Fund does not accept buy or sell orders. However, the value of the Fund’s assets may still be affected on such days to the extent that the Fund holds foreign securities that trade on days that foreign securities markets are open.

Equity securities are valued primarily on the basis of market quotations reported on stock exchanges and other securities markets around the world. Certain equity securities, debt securities and other assets are valued differently. For instance, short-term investments maturing in 60 days or less are valued primarily using the amortized cost method and those maturing in excess of 60 days are valued at the readily available market price. For a Fund organized as a fund-of-funds, its investments in other funds are valued at their NAVs. Market quotations are obtained from outside pricing services approved and monitored pursuant to a policy approved by the Fund’s Board.

If a market price is not readily available or is deemed not to reflect market value, the security will be valued in good faith based on a determination of the security's fair value pursuant to the Portfolio Pricing Policy approved by the Board. The Portfolio Pricing Policy provides that fair value determinations will be made using the methodology set forth in the Policy and deemed most appropriate under the circumstances and considering all available, relevant factors and indications of value. The Portfolio Pricing Policy provides that fair valuation may be used to price securities that trade on a foreign exchange when a significant event has occurred after the foreign exchange closes but before the time at which the Fund's share price is calculated. In addition, a statistical fair valuation process is applied daily to adjust prices of foreign securities traded on foreign exchanges in time zones different from the United States utilizing the services of a designated pricing vendor. Although the use of statistical fair valuation is intended to and may decrease opportunities for time zone arbitrage transactions, there can be no assurance that it will successfully decrease arbitrage opportunities. Please consult the SAI for more information on the factors to be considered in making fair value determinations; the significant events that may necessitate fair valuation of foreign securities; and the Fund's statistical fair valuation methodology.

When fair valuation is used to price securities, the values for those securities may be higher or lower than values used by another fund to price the security. Also, the use of fair valuation may cause the Fund's performance to diverge to a greater degree from the performance of various benchmarks used to compare the Fund's performance

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because benchmarks generally do not use fair valuation techniques. Because of the judgment involved in fair valuation decisions, there can be no assurance that the value ascribed to a particular security is accurate. The Fund's NAV is calculated based on the NAVs of the underlying Portfolio Funds in which it invests. The prospectuses of the Portfolio Funds explain the circumstances under which the Portfolio Funds used fair value pricing and the effects thereof.

Transaction Rules and Policies

The Fund, the Distributor or the Transfer Agent may refuse any order to buy or exchange shares. If this happens, the Fund will return any money it received, but no interest will be paid on that money. Your financial intermediary may have rules and policies in place that are in addition to or different than those described below.

Order Processing

Orders to buy, sell or exchange Fund shares are processed on business days. Depending upon the class of shares, orders can be made by mail, by telephone or online. Orders received in “good form” by the Transfer Agent or your financial intermediary before the end of a business day are priced at the NAV per share (plus any applicable sales charge) of the Fund's applicable share class on that day. Orders received after the end of a business day will receive the next business day's NAV per share (plus any applicable sales charge). For Direct-at-Fund Accounts (as defined below), when a written order to buy, sell or exchange shares is sent to the Transfer Agent, the share price used to fill the order is the next price calculated by the Fund after the Transfer Agent receives the transaction request in “good form” at its transaction processing center (i.e., the Fund’s express mail address), not the P.O. Box provided for regular mail delivery. The market value of the Fund's investments may change between the time you submit your order and the time the Fund next calculates its NAV per share. The business day that applies to your order is also called the trade date.

“Good Form”

An order is in “good form” if the Transfer Agent or your financial intermediary has received payment (in the case of purchases) and all of the information and documentation it deems necessary to effect your order. For example, when you sell shares, “good form” means that your request (i) has complete instructions and written requests include the signatures of all account owners, (ii) is for an amount that is less than or equal to the shares in your account for which payment has been received and collected, (iii) has a Medallion Signature Guarantee for amounts greater than $100,000 and certain other transactions, as described below, and (iv) includes any other required documents completed and attached. For the documents required for sales by corporations, agents, fiduciaries, surviving joint owners and other legal entities, call 800.345.6611.

Medallion Signature Guarantees

The Transfer Agent may require a Medallion Signature Guarantee for your signature in order to process certain transactions, including if: (i) the transaction amount is over $100,000; (ii) you want your check made payable to someone other than the registered account owner(s); (iii) the address of record has changed within the last 30 days; (iv) you want the check mailed to an address other than the address of record; (v) you want proceeds to be sent according to existing bank account instructions not coded for outgoing Automated Clearing House (ACH) or wire, or to a bank account not on file; or (vi) you are changing legal ownership of your account.

A Medallion Signature Guarantee helps assure that a signature is genuine and not a forgery. A Medallion Signature Guarantee must be provided by an eligible guarantor institution including, but not limited to, the following: a bank, credit union, savings association, broker or dealer that participates in the Securities Transfer Association Medallion Program (STAMP), the Stock Exchange Medallion Program (SEMP) or the New York Stock Exchange Medallion Signature Program (MSP). For other transactions, the Transfer Agent may require a signature guarantee. Notarization by a notary public is not an acceptable signature guarantee. The Transfer Agent reserves the right to reject a signature guarantee and to request additional documentation for any transaction.

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Buying, Selling and Exchanging Shares (continued)

Customer Identification Program

Federal law requires the Fund to obtain and record specific personal information to verify your identity when you open an account. This information may include your name, address, date of birth (for individuals) and taxpayer or other government issued identification (e.g., social security number (SSN) or other taxpayer identification number (TIN)). If you fail to provide the requested information, the Fund may need to delay the date of your purchase or may be unable to open your account, which may result in a return of your investment monies. In addition, if the Fund is unable to verify your identity after your account is open, the Fund reserves the right to close your account or take other steps as deemed reasonable. The Fund will not be liable for any loss resulting from any purchase delay, application rejection or account closure due to a failure to provide proper identifying information.

Small Account Policy — Class A, Class C, and Class Inst Share Accounts Below the Minimum Account Balance

The Funds generally will automatically sell your shares if the value of your Fund account (treating each account of the Fund you own separately from any other account of the Fund you may own) falls below the applicable minimum account balance. Any otherwise applicable CDSC will not be imposed on such an automatic sale of your shares. Generally, you may avoid such an automatic sale by raising your account balance to at least $250 or consolidating your multiple accounts you may have with the Funds through an exchange (so as to maintain at least $250 in each of your accounts). The minimum account balance varies among share classes and types of accounts, as follows:

Minimum Account Balance
	Minimum Account Balance
For all classes and account types except those listed below	$250 (None for accounts with Systematic Investment Plans)
Individual Retirement Accounts for all classes except those listed below	None
Class Adv, Class Inst2, Class Inst3 and Class R	None

For shares held directly with the Funds’ Transfer Agent, if your shares are sold, the Transfer Agent will remit the sale proceeds to you. The Transfer Agent will send you written notification in advance of any automatic sale, which will provide details on how you may avoid such an automatic sale. Generally, you may avoid such an automatic sale by raising your account balance to at least $250, consolidating your multiple accounts you may have with the Funds through an exchange (so as to maintain at least $250 in each of your accounts), or setting up a Systematic Investment Plan. For more information, contact the Transfer Agent or your financial intermediary. The Transfer Agent's contact information (toll-free number and mailing addresses) as well as the Funds’ website address can be found at the beginning of the section Choosing a Share Class.

For shares purchased and held for your benefit through a financial intermediary, the Funds may instruct the intermediary to automatically sell your Fund shares if the transaction can be operationally administered by the intermediary.

Small Account Policy — Class A, Class C, and Class Inst Share Accounts Minimum Balance Fee

If the value of your Fund account (treating each account of the Fund you own separately from any other account of the Fund you may own) falls below the minimum initial investment requirement applicable to you for any reason, including as a result of market decline, your account generally could be subject to a $20 annual fee. The Transfer Agent will reduce the expenses paid by the Fund by any amounts it collects from the assessment of this fee. For Funds that do not have transfer agency expenses against which to offset the amount collected through assessment of this fee, the fee will be paid directly to the Fund. The Funds reserve the right to lower the account size trigger point for the minimum balance fee in any year or for any class of shares when we believe it is appropriate to do so in light of declines in the market value of Fund shares or for other reasons.

For shares held directly with the Funds’ Transfer Agent, this fee will be assessed through the automatic sale of Fund shares in your account. Any otherwise applicable CDSC will not be imposed on such an automatic sale of your shares. The Transfer Agent will send you written notification in advance of assessing any fee, which will provide

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Buying, Selling and Exchanging Shares (continued)

details on how you can avoid the imposition of such fee. Generally, you may avoid the imposition of such fee by raising your Fund account balance, consolidating your multiple accounts you may have with the Funds, or setting up a Systematic Investment Plan that invests at least monthly. For more information, contact the Transfer Agent or your financial intermediary. The Transfer Agent's contact information (toll-free number and mailing addresses) as well as the Funds’ website address can be found at the beginning of the section Choosing a Share Class.

For shares purchased and held for your benefit through a financial intermediary, this fee could be assessed through the automatic sale of Fund shares in your account if instructed by the Fund and the transaction can be operationally administered by the intermediary.

Exceptions to the Small Account Policy (Accounts Below Minimum Account Balance) and Minimum Balance Fee

The automatic sale of Fund shares in accounts under $250 and the annual minimum balance fee described above do not apply to shareholders of Class Adv, Class Inst2, Class Inst3 and Class R shares; shareholders holding their shares through financial intermediary networked accounts; wrap fee and omnibus accounts; accounts with active monthly Systematic Investment Plans; certain qualified retirement plans; and health savings accounts. The automatic sale of Fund shares of accounts under the applicable minimum account balance does not apply to individual retirement plans.

Small Account Policy — Financial Intermediary Networked and Wrap Fee Accounts

The Funds may automatically redeem, at any time, financial intermediary networked accounts and wrap fee accounts that have account balances of $20 or less or have less than one share.

For shares purchased and held for your benefit through a financial intermediary, the Funds may instruct the intermediary to automatically sell your Fund shares if the transaction can be operationally administered by the intermediary.

Information Sharing Agreements

As required by Rule 22c-2 under the 1940 Act, the Funds or certain of their service providers will enter into information sharing agreements with financial intermediaries, including participating life insurance companies and financial intermediaries that sponsor or offer retirement plans through which shares of the Funds are made available for purchase. Pursuant to Rule 22c-2, financial intermediaries are required, upon request, to: (i) provide shareholder account and transaction information; and (ii) execute instructions from the Fund to restrict or prohibit further purchases of Fund shares by shareholders who have been identified by the Fund as having engaged in transactions that violate the Fund's excessive trading policies and procedures.

Excessive Trading Practices Policy

Right to Reject or Restrict Share Transaction Orders— The Fund is intended for investors with long-term investment purposes and is not intended as a vehicle for frequent trading activity (market timing) that is excessive. Investors should transact in Fund shares primarily for investment purposes. The Board has adopted excessive trading policies and procedures that are designed to deter excessive trading by investors (the Excessive Trading Policies and Procedures). The Fund discourages and does not accommodate excessive trading.

The Fund reserves the right to reject, without any prior notice, any purchase or exchange order for any reason, and will not be liable for any loss resulting from rejected orders. For example, the Fund may in its sole discretion restrict or reject a purchase or exchange order even if the transaction is not subject to the specific limitation described below if the Fund or its agents determine that accepting the order could interfere with efficient management of the Fund's portfolio or is otherwise contrary to the Fund's best interests. The Excessive Trading Policies and Procedures apply equally to purchase or exchange transactions communicated directly to the Transfer Agent and to those received by financial intermediaries.

Specific Buying and Exchanging Limitations — If the Fund detects that an investor has made two “material round trips” in any 28-day period, it will generally reject the investor's future purchase orders, including exchange purchase orders, involving any Fund.

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Buying, Selling and Exchanging Shares (continued)

For these purposes, a “round trip” is a purchase or exchange into the Fund followed by a sale or exchange out of the Fund, or a sale or exchange out of the Fund followed by a purchase or exchange into the Fund. A “material” round trip is one that is deemed by the Fund to be material in terms of its amount or its potential detrimental impact on the Fund. Independent of this limit, the Fund may, in its sole discretion, reject future purchase orders by any person, group or account that appears to have engaged in any type of excessive trading activity.

These limits generally do not apply to automated transactions or transactions by registered investment companies in a “fund-of-funds” structure. These limits do not apply to payroll deduction contributions by retirement plan participants, transactions initiated by a retirement plan sponsor or certain other retirement plan transactions consisting of rollover transactions, loan repayments and disbursements, and required minimum distribution redemptions. They may be modified or rescinded for accounts held by certain retirement plans to conform to plan limits, for considerations relating to the Employee Retirement Income Security Act of 1974 or regulations of the Department of Labor, and for certain asset allocation or wrap programs. Accounts known to be under common ownership or control generally will be counted together, but accounts maintained or managed by a common intermediary generally will not be considered to be under common ownership or control. The Fund reserves the right to modify these restrictions at any time without prior notice to shareholders. In addition, the Fund may, in its sole discretion, reinstate trading privileges that have been revoked under the Fund's Excessive Trading Policies and Procedures.

Limitations on the Ability to Detect and Prevent Excessive Trading Practices — The Fund takes various steps designed to detect and prevent excessive trading, including daily review of available shareholder transaction information. However, the Fund receives buy, sell or exchange orders through financial intermediaries, and cannot always know of or reasonably detect excessive trading that may be facilitated by financial intermediaries or by the use of the omnibus account arrangements they offer. Omnibus account arrangements are common forms of holding shares of mutual funds, particularly among certain financial intermediaries such as broker-dealers, retirement plans and variable insurance products. These arrangements often permit financial intermediaries to aggregate their clients' transactions and accounts, and in these circumstances, the identities of the financial intermediary clients that beneficially own Fund shares are often not known to the Fund.

Some financial intermediaries apply their own restrictions or policies to their clients’ transactions and accounts, which may be more or less restrictive than those described here. This may impact the Fund's ability to curtail excessive trading, even where it is identified. For these and other reasons, it is possible that excessive trading may occur despite the Fund's efforts to detect and prevent it.

Although these restrictions and policies involve judgments that are inherently subjective and may involve some selectivity in their application, the Fund seeks to act in a manner that it believes is consistent with the best interests of Fund shareholders in making any such judgments.

Risks of Excessive Trading — Excessive trading creates certain risks to the Fund's long-term shareholders and may create the following adverse effects:

■ negative impact on the Fund's performance;

■ potential dilution of the value of the Fund's shares;

■ interference with the efficient management of the Fund's portfolio, such as the need to maintain undesirably large cash positions, the need to use its line of credit or the need to buy or sell securities it otherwise would not have bought or sold;

■ losses on the sale of investments resulting from the need to sell securities at less favorable prices;

■ increased taxable gains to the Fund's remaining shareholders resulting from the need to sell securities to meet sell orders; and

■ increased brokerage and administrative costs.

To the extent that the Fund invests significantly in foreign securities traded on markets that close before the Fund's valuation time, it may be particularly susceptible to dilution as a result of excessive trading. Because events may occur after the close of foreign markets and before the Fund's valuation time that influence the value of foreign

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Buying, Selling and Exchanging Shares (continued)

securities, investors may seek to trade Fund shares in an effort to benefit from their understanding of the value of foreign securities as of the Fund's valuation time. This is often referred to as price arbitrage. The Fund has adopted procedures designed to adjust closing market prices of foreign securities under certain circumstances to reflect what the Fund believes to be the fair value of those securities as of its valuation time. To the extent the adjustments do not work fully, investors engaging in price arbitrage may cause dilution in the value of the Fund's shares held by other shareholders.

The Columbia Acorn Funds may invest in thinly traded equity securities of small-capitalization companies. Because

these securities are often traded infrequently, investors may seek to trade Fund shares in an effort to benefit from their understanding of the value of these securities as of the Fund's valuation time. This is also a type of price arbitrage. Any such frequent trading strategies may interfere with efficient management of the Fund's portfolio to a greater degree than would be the case for mutual funds that invest only, or significantly, in highly liquid securities, in part because the Fund may have difficulty selling these particular investments at advantageous times or prices to satisfy large and/or frequent sell orders. Any successful price arbitrage may also cause dilution in the value of Fund shares held by non-redeeming shareholders. The risks of excessive trading described above also apply to any Underlying Funds in which the Fund invests.

Opening an Account and Placing Orders

We encourage you to consult with a financial advisor who can help you with your investment decisions and who can help you open an account. Once you have an account, you can buy, sell or exchange shares by contacting your financial advisor who will send your order to the Transfer Agent or your financial intermediary. As described below, once you have an account you can also communicate your orders directly to the Transfer Agent by mail, by telephone or online.

The Funds are generally available directly and through broker-dealers, banks and other financial intermediaries or institutions, and through certain qualified and non-qualified plans, wrap fee products or other investment products sponsored by financial intermediaries. You may buy, sell, or exchange shares through your financial intermediary. If you maintain your account directly with your financial intermediary, you must contact that agent to process your transaction.

Not all financial intermediaries offer the Funds (or all classes of Fund shares) and certain financial intermediaries that offer the Funds may not offer all Funds on all investment platforms or programs. Please consult with your financial intermediary to determine the availability of the Funds. If you set up an account at a financial intermediary that does not have, and is unable to obtain, a selling agreement with the Distributor, you will not be able to transfer Fund holdings to that account. In that event, you must either maintain your Fund holdings with your current financial intermediary or find another financial intermediary with a selling agreement.

Financial intermediaries that offer the Funds may charge you additional fees for the services they provide and they may have different policies that are not described in this prospectus. An investor transacting in a class of Fund shares without any front-end sales charge, CDSC, or other asset-based fee for sales or distribution, such as a Rule 12b-1 fee, may be required to pay a commission to the financial intermediary for effecting such transactions. The Funds are offered in a number of different share classes that have different fees and expenses and other features. Some differences in the policies of different financial intermediaries may include different minimum investment amounts, exchange privileges, Fund/class choices and cutoff times for investments. Additionally, recordkeeping, transaction processing and payments of distributions relating to your account may be performed by the financial intermediaries through which your shares of the Fund are held. Since the Fund (and its service providers) may not have a record of your account transactions, you should always contact the financial intermediary through which you purchased or at which you maintain your shares of the Fund to make changes to your account, to give instructions concerning your account, or to obtain information about your account. The Fund and its service providers, including the Distributor and the Transfer Agent, are not responsible for the failure of any financial intermediary to carry out its obligations to its customers.

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Buying, Selling and Exchanging Shares (continued)

The Fund may engage financial intermediaries to receive purchase, exchange and sell orders on its behalf. Accounts established directly with the Fund will be serviced by the Transfer Agent. The Funds, the Transfer Agent and the Distributor do not provide investment advice.

Direct-At-Fund Accounts (Accounts Held Directly with the Fund)

Fund shares can be held in a variety of ways. You can hold Fund shares through an account established and held through the financial intermediary through which you purchased Fund shares, or you or your financial intermediary can establish an account directly with the Fund, in which case you will receive Fund account transaction confirmations and statements from the Transfer Agent, and not your financial intermediary (Direct-at-Fund Accounts). Direct-at-Fund Accounts include accounts held at the Transfer Agent that do not or no longer have a financial intermediary assigned to them.

To open a Direct-at-Fund Account, complete a Fund account application with your financial advisor or investment professional, and mail the account application to the Transfer Agent. Account applications may be obtained at columbiathreadneedleus.com or may be requested by calling 800.345.6611. Make your check payable to the Fund. You will be assessed a $15 fee for any checks rejected by your financial institution due to insufficient funds or other reasons. The Funds do not accept cash, credit card convenience checks, money orders, traveler's checks, starter checks, third or fourth party checks, or other cash equivalents.

Mail your check and completed application to the Transfer Agent at its regular or express mail address that can be found at the beginning of the section Choosing a Share Class. You may also use these addresses to request an exchange or redemption of Fund shares. When a written order to buy, sell or exchange shares is sent to the Transfer Agent, the share price used to fill the order is the next price calculated by the Fund after the Transfer Agent receives your transaction request in “good form” at its transaction processing center (i.e., the Fund’s express mail address), not the P.O. Box provided for regular mail delivery.

You will be sent a statement confirming your purchase and any subsequent transactions in your account. You will also be sent quarterly and annual statements detailing your transactions in the Fund and the other Funds you own under the same account. Duplicate quarterly account statements for the current year and duplicate annual statements for the most recent prior calendar year will be sent to you free of charge. Copies of year-end statements for prior years are available for a fee. Please contact the Transfer Agent for more information.

Written Transactions – Direct-at-Fund Accounts

If you have a Direct-at-Fund Account, you can communicate written buy, sell or exchange orders to the Transfer Agent at its address that can be found at the beginning of the section Choosing a Share Class. When a written order to buy, sell or exchange shares is sent to the Transfer Agent, the share price used to fill the order is the next price calculated by the Fund after the Transfer Agent receives your transaction request in “good form” at its transaction processing center (i.e., the Fund’s express mail address), not the P.O. Box provided for regular mail delivery.

Include in your transaction request letter: your name; the name of the Fund(s); your account number; the class of shares to be purchased, exchanged or sold; your SSN or other TIN; the dollar amount or number of shares you want to purchase, exchange or sell; specific instructions regarding delivery of any redemption proceeds or exchange destination (i.e., the Fund/class to be exchanged into); signature(s) of all registered account owner(s); and any special documents the Transfer Agent may require in order to process your order.

Corporate, trust or partnership accounts may need to send additional documents. Payment will be mailed to the address of record and made payable to the names listed on the account, unless your request specifies differently and is signed by all owners.

Telephone Transactions – Direct-at-Fund Accounts

For Class A, Class C, Class Inst, Class Inst3 and Class R shares, if you have a Direct-at-Fund Account, you may place orders to buy, sell or exchange shares by telephone through the Transfer Agent. To place orders by telephone, call 800.422.3737. Have your account number and SSN or TIN available when calling.

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You can sell Fund shares via telephone and receive redemption proceeds: by electronic funds transfer via ACH, by wire, or by check to the address of record, subject to a maximum of $100,000 of shares per day, per Fund account. You can buy Fund shares via telephone by electronic funds transfer via ACH from your bank account up to a maximum of $100,000 of shares per day, per Fund account, or by wire from your bank account without a maximum. See below for more information regarding wire and electronic fund transfer transactions. Certain restrictions apply, so please call the Transfer Agent at 800.422.3737 for this and other information in advance of any need to transact via telephone.

Telephone orders may not be as secure as written orders. The Fund will take reasonable steps to confirm that telephone instructions are genuine. For example, we require proof of your identification before we will act on instructions received by telephone and may record telephone conversations. However, the Fund and its agents will not be responsible for any losses, costs or expenses resulting from an unauthorized telephone instruction when reasonable steps have been taken to confirm that telephone instructions are genuine. Telephone orders may be difficult to complete during periods of significant economic or market change or business interruption.

Online Transactions – Direct-at-Fund Accounts

For Class A, Class C, Class Inst, Class Inst3 and Class R shares, if you have a Direct-at-Fund Account, you may be able to place orders to buy, sell, or exchange shares online. Contact the Transfer Agent at 800.345.6611 for more information on certain account trading restrictions and the special sign-up procedures required for online transactions. You can also go to columbiathreadneedleus.com/investor/ to sign up for online transactions. The Transfer Agent has procedures in place to authenticate electronic orders you send through the internet. You will be required to accept the terms of an online agreement and to establish an online account and utilize a password in order to access online account services. You can sell a maximum of $100,000 of shares per day, per Fund account through your online account if you qualify for internet orders. Wire transactions are not permitted online.

Wire Transactions – Direct-at-Fund Accounts

If you hold a Direct-at-Fund Account, you may purchase or redeem Class A, Class C, Class Inst, Class Inst3 and Class R shares of a Fund by wiring money from (or to) your bank account to (or from) your Fund account. You must set up this feature prior to your request unless you are submitting your request in writing, which may require a Medallion Signature Guarantee. Please contact the Transfer Agent by calling 800.422.3737 to obtain the necessary forms and requirements. The Transfer Agent charges a fee for shares sold by wire. The Transfer Agent may waive the fee for certain accounts. In the case of a redemption, the receiving bank may charge an additional fee. The minimum amount that can be redeemed by wire is $500. When selling Fund shares via a telephone request, the maximum amount that can be redeemed via wire transfer is $100,000 per day, per Fund account. Wire transactions are not permitted online.

Electronic Funds Transfer via ACH – Direct-at-Fund Accounts

If you hold a Direct-at-Fund Account, you may purchase or redeem Class A, Class C, Class Inst, Class Inst3 and Class R shares of a Fund by electronically transferring money via Automated Clearing House (ACH) from (or to) your bank account to (or from) your Fund account subject to a maximum of $100,000 of shares per day, per Fund account. You must set up this feature prior to your request, unless you are submitting your request in writing, which may require a Medallion Signature Guarantee. Please contact the Transfer Agent by calling 800.422.3737 to obtain the necessary forms and requirements. Your bank may take up to three business days to post an electronic funds transfer to (or from) your Fund account.

Buying Shares

Eligible Investors

Class A Shares

Class A shares are available to the general public for investment.

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Class Adv Shares

Class Adv shares are available only to (i) omnibus retirement plans, including self-directed brokerage accounts within omnibus retirement plans that clear through institutional no transaction fee (NTF) platforms, (ii) trust companies or similar institutions, (iii) broker-dealers, banks, trust companies and similar institutions that clear Fund share transactions for their client or customer investment advisory or similar accounts through designated financial intermediaries and their mutual fund trading platforms that have been granted specific written authorization from the Transfer Agent with respect to Class Adv eligibility apart from selling, servicing or similar agreements, (iv) 501(c)(3) charitable organizations, (v) 529 plans, (vi) health savings accounts, (vii) investors participating in a fee-based advisory program sponsored by a financial intermediary or other entity that is not compensated by the Fund for those services, other than payments for shareholder servicing or sub-accounting performed in place of the Transfer Agent, and (viii) commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Adv shares within such platform.

Class C Shares

Class C shares are available to the general public for investment, except that Direct-at-Fund Accounts that do not have a financial intermediary assigned to them are not permitted to purchase Class C shares; Class C share purchase orders received on or after such date from Direct-at-Fund Accounts that do not have a financial intermediary assigned to the account will automatically be invested in Class A shares of the same Fund.

Class Inst Shares

Class Inst shares are available only to the categories of eligible investors described below under Class Inst Shares Minimum Initial Investments. Financial intermediaries that clear Fund share transactions through designated financial intermediaries and their mutual fund trading platforms that were given specific written notice from the Transfer Agent of the termination, effective March 29, 2013, of their eligibility for new purchases of Class Inst shares and omnibus retirement plans are not permitted to establish new Class Inst accounts, subject to certain exceptions described below.

Omnibus retirement plans that opened and, subject to certain exceptions, funded a Class Inst account with the Fund as of the close of business on March 28, 2013 and have continuously held Class Inst shares in such account after such date (each, a grandfathered plan), may generally continue to make additional purchases of Class Inst shares, open new Class Inst accounts and add new participants. In addition, an omnibus retirement plan affiliated with a grandfathered plan may, in the sole discretion of the Distributor, open new Class Inst accounts in a Fund if the affiliated plan opened a Class Inst account on or before March 28, 2013. If an omnibus retirement plan invested in Class Inst shares changes recordkeepers after March 28, 2013, any new accounts established for that plan may not be established in Class Inst shares, but such a plan may establish new accounts in a different share class for which the plan is eligible.

Accounts of financial intermediaries (other than omnibus retirement plans, which are discussed above) that clear Fund share transactions for their client or customer accounts through designated financial intermediaries and their mutual fund trading platforms that received specific written notice from the Transfer Agent of the termination, effective March 29, 2013, of their eligibility for new purchases of Class Inst shares will not be permitted to establish new Class Inst accounts or make additional purchases of Class Inst shares (other than through reinvestment of distributions). Any such account may, at its holder’s option, exchange Class Inst shares of a Fund, without the payment of a sales charge, for Class A shares of the same Fund.

Class Inst2 Shares

Class Inst2 shares are available only to (i) certain registered investment advisers and family offices that clear Fund share transactions for their client or customer accounts through designated financial intermediaries and their mutual fund trading platforms that have been granted specific written authorization from the Transfer Agent with respect to Class Inst2 eligibility apart from selling, servicing or similar agreements; (ii) omnibus retirement plans; (iii) health savings accounts, provided that the financial intermediary has an agreement with the Distributor that specifically

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authorizes offering Class Inst2 shares within such platform and that Fund shares are held in an omnibus account; and (iv) institutional investors that are clients of the Columbia Threadneedle Global Institutional Distribution Team that invest in Class Inst2 shares for their own account through platforms approved by the Distributor or an affiliate thereof to offer and/or service Class Inst2 shares within such platform. Prior to November 8, 2012, Class Inst2 shares were closed to new investors and new accounts, subject to certain exceptions. Existing shareholders who do not satisfy the new eligibility requirements for investment in Class Inst2 may not establish new Class Inst2 accounts but may continue to make additional purchases of Class Inst2 shares in accounts opened and funded prior to November 8, 2012; provided, however, that investment advisory programs and similar programs that opened a Class Inst2 account as of May 1, 2010, and continuously hold Class Inst2 shares in such account after such date, may generally not only continue to make additional purchases of Class Inst2 shares but also open new Class Inst2 accounts for such pre-existing programs and add new shareholders in the program.

Class Inst3 Shares

Class Inst3 shares are available to: (i) group retirement plans that maintain plan-level or omnibus accounts with the Fund (through the Transfer Agent); (ii) institutional investors that are clients of the Columbia Threadneedle Global Institutional Distribution Team that invest in Class Inst3 shares for their own account through platforms approved by the Distributor or an affiliate thereof to offer and/or service Class Inst3 shares within such platform; (iii) collective trust funds; (iv) affiliated or unaffiliated mutual funds (e.g., funds operating as funds-of-funds); (v) fee-based platforms of financial intermediaries (or the clearing intermediary that they trade through) that have an agreement with the Distributor or an affiliate thereof that specifically authorizes the financial intermediary to offer and/or service Class Inst3 shares within such platform, provided also that Fund shares are held in an omnibus account; (vi) commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst3 shares within such platform and that Fund shares are held in an omnibus account; (vii) health savings accounts, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst3 shares within such platform and that Fund shares are held in an omnibus account; and (viii) bank trust departments, subject to an agreement with the Distributor that specifically authorizes offering Class Inst3 shares and provided that Fund shares are held in an omnibus account. In each case above where noted that Fund shares are required to be held in an omnibus account, the Distributor may, in its discretion, determine to waive this requirement.

Class R Shares

Class R shares are available only to eligible health savings accounts sponsored by third party platforms, including those sponsored by Ameriprise Financial affiliates, eligible retirement plans and, in the sole discretion of the Distributor, other types of retirement accounts held through platforms maintained by financial intermediaries approved by the Distributor. Eligible retirement plans include any retirement plan other than individual 403(b) plans. Class R shares are generally not available for investment through retail nonretirement accounts, traditional and Roth IRAs, Coverdell Education Savings Accounts, SEPs, SAR-SEPs, Simple IRAs or 529 tuition programs. Contact the Transfer Agent or your retirement plan or health savings account administrator for more information about investing in Class R shares.

Additional Eligible Investors

In addition, the Distributor, in its sole discretion, may accept investments in any share class from investors other than those listed in this prospectus, and may also waive certain eligibility requirements for operational and other reasons, including but not limited to any requirement to maintain Fund shares in networked or omnibus accounts.

Minimum Initial Investments

The table below shows the Fund’s minimum initial investment requirements, which may vary by class and type of account.

The Fund reserves the right to redeem your shares if your account falls below the Fund’s minimum initial investment requirement.

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Minimum Initial Investments
	Minimum Initial Investment(a)	Minimum Initial Investment for Accounts with Systematic Investment Plans
For all classes and account types except those listed below	$2,000	$100
Individual Retirement Accounts for all classes except those listed below	$1,000	$100
Group retirement plans	None	N/A
Class Adv and Class Inst	$0, $1,000 or $2,000(b)	$100(b)
Class Inst2 and Class R	None	N/A
Class Inst3	$0, $1,000, $2,000 or $1 million(c)	$100(c)

(a) If your Class A, Class Adv, Class C, Class Inst, or Class Inst3 shares account balance falls below the minimum initial investment amount for any reason, including a market decline, you may be asked to increase it to the minimum initial investment amount or establish a monthly Systematic Investment Plan. If you do not do so, your account will be subject to a $20 annual low balance fee and/or shares may be automatically redeemed and the proceeds mailed to you if the account falls below the minimum account balance. See Buying, Selling and Exchanging Shares — Transaction Rules and Policies above. There is no minimum initial investment in Class A shares for accounts held in an omnibus account on a mutual fund only platform offered through your financial intermediary.

(b) The minimum initial investment in Class Adv shares is $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts) for commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customers, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Adv shares within such platform; for all other eligible Class Adv share investors (see Buying Shares – Eligible Investors – Class Adv Shares above), there is no minimum initial investment. The minimum initial investment amount for Class Inst shares is $0, $1,000 or $2,000 depending upon the category of eligible investor. See — Class Inst Shares Minimum Initial Investments below. The minimum initial investment amount for Systematic Investment Plan accounts is the same as the amount set forth in the first two rows of the table, as applicable.

(c) There is no minimum initial investment in Class Inst3 shares for: group retirement plans that maintain plan-level or omnibus accounts with the Fund; collective trust funds; affiliated or unaffiliated mutual funds (e.g., funds operating as funds-of-funds); and fee -based platforms of financial intermediaries (or the clearing intermediary that they trade through) that have an agreement with the Distributor or an affiliate thereof that specifically authorizes the financial intermediary to offer and/or service Class Inst3 shares within such platform and Fund shares are held in an omnibus account. The minimum initial investment in Class Inst3 shares is $2,000 ($1,000 for IRAs; $100 for monthly Systematic Investment Plan accounts) for commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst3 shares within such platform and Fund shares are held in an omnibus account. The minimum initial investment in Class Inst3 shares is $1 million, unless waived in the discretion of the Distributor, for the following investors: institutional investors that are clients of the Columbia Threadneedle Global Institutional Distribution Team that invest in Class Inst3 shares for their own account through platforms approved by the Distributor or an affiliate thereof to offer and/or service Class Inst3 shares within such platform; and bank trust departments, subject to an agreement with the Distributor that specifically authorizes offering Class Inst3 shares and provided that Fund shares are held in an omnibus account. The Distributor may, in its discretion, waive the $1 million minimum initial investment required for these Class Inst3 investors. In each case above where noted that Fund shares are required to be held in an omnibus account, the Distributor, may, in its discretion, determine to waive this requirement.

Additional Information about Minimum Initial Investments

The minimum initial investment requirements may be waived for accounts that are managed by an investment professional, or for accounts held in approved discretionary or non-discretionary wrap programs. The Distributor, in its sole discretion, may also waive minimum initial investment requirements for other account types.

Minimum investment and related requirements may be modified at any time, with or without prior notice. If your account is closed and then re-opened with a Systematic Investment Plan, your account must meet the then-current applicable minimum initial investment.

Class Inst Shares Minimum Initial Investments

There is no minimum initial investment in Class Inst shares for the following categories of eligible investors:

■ Any health savings account sponsored by a third party platform.

■ Any investor participating in an account sponsored by a financial intermediary or other entity (that provides services to the account) that is paid a fee-based advisory fee by the investor and that is not compensated by the Fund for those services, other than payments for shareholder servicing or sub-accounting performed in place of the Transfer Agent.

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■ Any commissionable brokerage account, if a financial intermediary has received a written approval from the Distributor to waive the minimum initial investment in Class Inst shares.

■ Any Trustee (or family member) of Columbia Acorn Trust.

■ Any employee (or family member) of the Investment Manager.

The minimum initial investment in Class Inst shares for the following categories of eligible investors is $1,000:

■ Individual retirement accounts (IRAs) on commissionable brokerage platforms where the financial intermediary, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares, provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst shares within such platform.

■ Any current employee of Columbia Management Investment Advisers LLC, the Distributor or the Transfer Agent and immediate family members of any of the foregoing who share the same address are eligible to invest in Class Inst shares through an individual retirement account (IRA). If you maintain your account with a financial intermediary, you must contact that financial intermediary each time you seek to purchase shares to notify them that you qualify for Class Inst shares. If Class Inst shares are not available at your financial intermediary, you may consider opening a Direct-at-Fund Account. It is your obligation to advise your financial intermediary or (in the case of Direct-at-Fund Accounts) the Transfer Agent that you qualify for Class Inst shares; be prepared to provide proof thereof.

The minimum initial investment in Class Inst shares for the following categories of eligible investors is $2,000:

■ Investors (except investors in individual retirement accounts (IRAs)) who purchase Fund shares through commissionable brokerage platforms where the financial intermediary holds the shares in an omnibus account and, acting as broker on behalf of its customer, charges the customer a commission for effecting transactions in Fund shares provided that the financial intermediary has an agreement with the Distributor that specifically authorizes offering Class Inst shares within such platform.

■ Any current employee of Columbia Management Investment Advisers LLC, the Distributor or the Transfer Agent and immediate family members of any of the foregoing who share the same address are eligible to invest in Class Inst shares (other than individual retirement accounts (IRAs), for which the minimum initial investment is $1,000). If you maintain your account with a financial intermediary, you must contact that financial intermediary each time you seek to purchase shares to notify them that you qualify for Class Inst shares. If Class Inst shares are not available at your financial intermediary, you may consider opening a Direct-at-Fund Account. It is your obligation to advise your financial intermediary or (in the case of Direct-at-Fund Accounts) the Transfer Agent that you qualify for Class Inst shares; be prepared to provide proof thereof.

■ Certain financial institutions and intermediaries, such as insurance companies, trust companies, banks, endowments, investment companies or foundations, buying shares for their own account, including Ameriprise Financial and its affiliates and/or subsidiaries.

■ Bank trust departments that assess their clients an asset-based fee.

■ Any trustee or director (or family member of a trustee or director) of a fund distributed by the Distributor (other than the Columbia Acorn Funds).

■ Certain other investors as set forth in more detail in the SAI.

Systematic Investment Plan

The Systematic Investment Plan allows you to schedule regular purchases via automatic transfers from your bank account to the Fund on a monthly, quarterly or semiannual basis. Contact the Transfer Agent or your financial intermediary to set up the plan. Systematic Investment Plans may not be available for all share classes. With the exception of Columbia Government Money Market Fund, Systematic Investment Plan purchases will be confirmed on your quarterly account statement. Columbia Government Money Market Fund Systematic Investment Plan purchases will be confirmed at the time of the purchase. If establishing a Systematic Investment Plan to reduce the initial fund minimum, the plan needs to be established monthly to avoid the small account fee.

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Dividend Diversification

Generally, you may automatically invest Fund distributions into the same class of shares (and in some cases certain other classes of shares) of another Fund without paying any applicable front-end sales charge. Call the Transfer Agent at 800.345.6611 for details. The ability to invest distributions from one Fund to another Fund may not be available to accounts held at all financial intermediaries.

Other Purchase Rules You Should Know

■ Once the Transfer Agent or your financial intermediary receives your purchase order in “good form,” your purchase will be made at the Fund’s next calculated public offering price per share, which is the NAV per share plus any sales charge that applies (i.e., the trade date).

■ Once the Fund receives your purchase request in “good form,” you cannot cancel it after the market closes.

■ You generally buy Class A shares at the public offering price per share because purchases of these share classes are generally subject to a front-end sales charge.

■ You buy Class Adv, Class C, Class Inst, Class Inst2, Class Inst3 and Class R shares at NAV per share because no front-end sales charge applies to purchases of these share classes.

■ The Distributor and the Transfer Agent reserve the right to cancel your order request if the Fund does not receive payment within two business days of receiving your purchase order request. The Fund will return any payment received for orders that have been cancelled, but no interest will be paid on that money.

■ Financial intermediaries are responsible for sending your purchase orders to the Transfer Agent and ensuring that the Fund receives your money on time.

■ Shares purchased are recorded on the books of the Fund. The Fund does not issue certificates.

■ You generally may make a purchase only into a Fund that is accepting investments.

Please also read Appendix A and contact your financial intermediary for more information regarding any reductions and/or waivers described therein.

Selling Shares

When you sell shares, the amount you receive may be more or less than the amount you invested. Your sale price will be the next NAV calculated after your request is received in “good form,” (i.e., the trade date) minus any applicable CDSC.

Systematic Withdrawal Plan

The Systematic Withdrawal Plan allows you to schedule regular redemptions from your account any business day on a monthly, quarterly or semiannual basis. Currently, Systematic Withdrawal Plans are generally available for Class A, Class Adv, Class C, Class Inst, Class Inst2, and Class Inst3 share accounts. Contact the Transfer Agent or your financial intermediary to set up the plan. To set up the plan, your account balance must meet the class minimum initial investment amount. A Systematic Withdrawal Plan cannot be set up on an account that already has a Systematic Investment Plan established. Note that a Medallion Signature Guarantee may be required if this service is established after your Fund account is opened.

You can choose to receive your withdrawals via check or direct deposit into your bank account. The Fund will deduct any applicable CDSC from the withdrawals before sending redemption proceeds to you. You can cancel the plan by giving the Fund 30 days’ notice in writing or by calling the Transfer Agent at 800.422.3737. It’s important to remember that if you withdraw more than your investment in the Fund is earning, you'll eventually withdraw your entire investment.

Satisfying Fund Redemption Requests

When you sell your Fund shares, the Fund is effectively buying them back from you. This is called a redemption. Except as noted below with respect to newly purchased shares, the Fund typically expects to send you payment for your shares within two business days after your trade date. The Fund can suspend redemptions and/or delay

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payment of redemption proceeds for up to seven days. The Fund can also suspend redemptions and/or delay payment of redemption proceeds in excess of seven days under certain circumstances, including when the NYSE is closed or trading thereon is restricted or during emergency or other circumstances, including as determined by the SEC.

The Fund typically seeks to satisfy redemption requests from cash or cash equivalents held by the Fund, from the proceeds of orders to purchase Fund shares or from the proceeds of sales of Fund holdings effected in the normal course of managing the Fund. However, the Fund may have to sell Fund holdings, including in down markets, to meet heavier than usual redemption requests. For example, under stressed or abnormal market conditions or circumstances, including circumstances adversely affecting the liquidity of the Fund’s investments, the Fund may be more likely to be forced to sell Fund holdings to meet redemptions than under normal market circumstances. In these situations, the Fund’s portfolio managers may have to sell Fund holdings that would not otherwise be sold because, among other reasons, the current price to be received is less than the value of the holdings perceived by the Fund’s portfolio managers. The Fund may also, under certain circumstances (likely under stressed or abnormal market conditions or circumstances), borrow money under a credit facility to which the Fund and certain other Columbia Funds are parties. The Fund and the other Columbia Funds are limited as to the amount that each may individually and collectively borrow under the credit facility. As a result, borrowings available to the Fund under the credit facility might be insufficient, alone or in combination with the other strategies described herein, to satisfy Fund redemption requests. Please see About Fund Investments – Borrowings in the SAI for more information about the credit facility. The Fund is also limited in the total amount it may borrow. Please see About Fund Investments – Fundamental and Non-Fundamental Investment Policies in the SAI for more information about borrowing.

In addition, the Fund reserves the right to honor redemption orders in whole or in part with in-kind distributions of Fund portfolio securities instead of cash. Such in-kind distributions typically represent a pro-rata portion of Fund portfolio assets subject to adjustments (e.g., for non-transferable securities, round lots, and derivatives, if any). In the event the Fund distributes portfolio securities in kind, you may incur brokerage and other transaction costs associated with converting the portfolio securities you receive into cash. Also, the portfolio securities you receive may increase or decrease in value after they are distributed but before you convert them into cash. For U.S. federal income tax purposes, redemptions paid in securities are generally treated the same as redemptions paid in cash. The Trust has elected to be governed by Rule 18f-1 under the 1940 Act, which means that for each redeeming shareholder, the first $250,000, or 1% of the Fund's net asset value, whichever is less, will be paid in cash or cash equivalents and the remainder may be paid in kind.

While the Fund is not required (and may refuse in its discretion) to pay a redemption with an in-kind distribution of Fund portfolio securities and reserves the right to pay the redemption proceeds in cash, if you wish to request an in-kind redemption, please call the Transfer Agent at 800.345.6611. As a result of the operational steps needed to coordinate with the redeeming shareholder’s custodian, in-kind redemptions typically take several weeks to complete after a redemption request is received. The Fund and the redeeming shareholder will typically agree upon a redemption date. Since the Fund’s NAV may fluctuate during this time, the Fund’s NAV may be lower on the agreed-upon redemption date than on an earlier date on which the investment could have been redeemed for cash.

Redemption of Newly Purchased Shares

You may not redeem shares for which the Fund has not yet received payment. Shares purchased by check or electronically by ACH when the purchase payment is not guaranteed will be considered in “good form” for redemption only after they have been held in your account for 6 calendar days after the trade date of the purchase (Collected Shares). If you request a redemption for an amount that, based on the NAV next calculated after your redemption request is received, includes any shares that are not yet Collected Shares, the Fund will only process the redemption up to the amount of the value of Collected Shares available in your account. You must submit a new redemption request if you wish to redeem those shares that were not yet Collected Shares at the time the original redemption request was received by the Fund.

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Other Redemption Rules You Should Know

■ Once the Transfer Agent or your financial intermediary receives your redemption order in “good form,” your shares will be sold at the Fund’s next calculated NAV per share (i.e., the trade date). Any applicable CDSC will be deducted from the amount you're selling and the balance will be remitted to you.

■ Once the Fund receives your redemption request in “good form,” you cannot cancel it after the market closes.

■ The Distributor, in its sole discretion, reserves the right to liquidate Fund shares (of any class of the Fund) held in an omnibus account of a financial intermediary that clears Fund share transactions through a clearing intermediary or platform that charges certain maintenance fees to the Fund if the value of the omnibus account, at the Fund share class (i.e., CUSIP) level, falls below $100,000 (a CUSIP Liquidation Event). The Distributor will provide at least 90 days’ notice of a CUSIP Liquidation Event to financial intermediaries with impacted omnibus accounts. Shareholders invested in the Fund through such omnibus accounts can request through their financial intermediary a tax-free exchange to Class A shares or shareholders can consider holding their Fund shares in a Direct-at-Fund Account, provided requirements to transfer the account are fulfilled. You should discuss your options with your financial intermediary.

■ If you sell your shares that are held in a Direct-at-Fund Account, we will normally send the redemption proceeds by mail or electronically transfer them to your bank account the next business day after the trade date. Note that your bank may take up to three business days to post an electronic funds transfer from your account.

■ If you sell your shares through a financial intermediary, the Funds will normally send the redemption proceeds to your financial intermediary within two business days after the trade date.

■ No interest will be paid on uncashed redemption checks.

■ Other restrictions may apply to retirement accounts. For information about these restrictions, contact your retirement plan administrator.

■ For broker-dealer and wrap fee accounts: The Fund reserves the right to redeem your shares if your account falls below the Fund's minimum initial investment requirement. The Fund will notify your broker-dealer prior to redeeming shares, and will provide details on how to avoid such redemption.

■ Also keep in mind the Funds' Small Account Policy, which is described above in Buying, Selling and Exchanging Shares — Transaction Rules and Policies.

Exchanging Shares

You can generally sell shares of your Fund to buy shares of another Fund (subject to eligibility requirements), in what is called an exchange. You should read the prospectus of, and make sure you understand the investment objective, principal investment strategies, risks, fees and expenses of, the Fund into which you are exchanging. Although the Funds allow certain exchanges from one share class to another share class with higher expenses, you should consider the expenses of each class before making such an exchange. Please see Same-Fund Exchange Privilege below for more information.

You will be subject to a sales charge if, in a Direct-at-Fund Account, you exchange shares that have not previously paid a sales charge, including from Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia U.S. Treasury Index Fund or any other Columbia Fund that does not charge a front-end sales charge, into a Columbia Fund that does assess a sales charge. If you hold your Fund shares through certain financial intermediaries, you may have limited exchangeability among the Funds. Please contact your financial intermediary for more information.

Systematic Exchanges

You may buy Class A, Class C, Class Inst and Class Inst3 shares of a Fund by exchanging each month from another Fund for shares of the same class of the Fund at no additional cost, subject to the following exchange amount minimums: $50 each month for individual retirement accounts (i.e., tax qualified accounts); and $100 each month for non-retirement accounts. Contact the Transfer Agent or your financial intermediary to set up the plan.

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Exchanges will continue as long as your balance in the Fund you are exchanging shares from is sufficient to complete the systematic monthly exchange, subject to the Funds' Small Account Policy described above in Buying, Selling and Exchanging Shares — Transaction Rules and Policies. You may terminate the program or change the amount you would like to exchange (subject to the $50 and $100 minimum requirements noted immediately above) by calling the Transfer Agent at 800.345.6611.

Other Exchange Rules You Should Know

■ Exchanges are made at the NAV next calculated (plus any applicable sales charge) after your exchange order is received in “good form” (i.e., the trade date).

■ Once the Fund receives your exchange request in “good form,” you cannot cancel it after the market closes.

■ The rules for buying shares of a Fund generally apply to exchanges into that Fund, including, if your exchange creates a new Fund account, it must satisfy the minimum investment amount, unless a waiver applies.

■ Shares of the purchased Fund may not be used on the same day for another exchange or sale.

■ If you exchange shares from Class A shares of Columbia Government Money Market Fund to a non-money market Fund, any further exchanges must be between shares of the same class. For example, if you exchange from Class A shares of Columbia Government Money Market Fund into Class C shares of a non-money market Fund, you may not exchange from Class C shares of that non-money market Fund back to Class A shares of Columbia Government Money Market Fund or Class A shares of any other Fund.

■ A sales charge may apply when you exchange shares of a Fund that were not assessed a sales charge at the time you purchased such shares. If you invest through a Direct-at-Fund Account in Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund, Columbia U.S. Treasury Index Fund or any other Columbia Fund that does not impose a front-end sales charge and then you exchange into a Fund that does assess a sales charge, your transaction is subject to a front-end sales charge if you exchange into Class A shares and to a CDSC if you exchange into Class C shares of the Columbia Funds.

■ If you purchased Class A shares of a Columbia Fund that imposes a front-end sales charge (and you paid any applicable sales charge) and you then exchange those shares into Columbia Government Money Market Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Mid Cap Index Fund, Columbia Small Cap Index Fund, Columbia Ultra Short Municipal Bond Fund, Columbia Ultra Short Term Bond Fund, Columbia U.S. Treasury Index Fund or any other Columbia Fund that does not impose a front-end sales charge, you may exchange that amount to Class A of another Fund in the future, including dividends earned on that amount, without paying a sales charge.

■ If your shares are subject to a CDSC, you will not be charged a CDSC upon the exchange of those shares. Any CDSC will be deducted when you sell the shares you received from the exchange. The CDSC imposed at that time will be based on the period that begins when you bought shares of the original Fund and ends when you sell the shares of the Fund you received from the exchange. Any applicable CDSC charged will be the CDSC of the original Fund.

■ You may make exchanges only into a Fund that is legally offered and sold in your state of residence. Contact the Transfer Agent or your financial intermediary for more information.

■ You generally may make an exchange only into a Fund that is accepting investments.

■ The Fund may change or cancel your right to make an exchange by giving the amount of notice required by regulatory authorities (generally 60 days for a material change or cancellation).

■ Unless your account is part of a tax-advantaged arrangement, an exchange for shares of another Fund is a taxable event, and you may recognize a gain or loss for tax purposes.

■ Changing your investment to a different Fund will be treated as a sale and purchase, and you will be subject to applicable taxes on the sale and sales charges on the purchase of the new Fund.

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Buying, Selling and Exchanging Shares (continued)

■ Class Inst shares of a Fund may be exchanged for Class A or Class Inst shares of another Fund. In certain circumstances, the front-end sales charge applicable to Class A shares may be waived on exchanges of Class Inst shares for Class A shares. See Buying, Selling and Exchanging Shares — Buying Shares — Eligible Investors — Class Inst Shares for details.

Same-Fund Exchange Privilege

Shareholders may be eligible to invest in other classes of shares of the same Fund, and may exchange their current shares for another share class if deemed eligible and offered by the Fund. Such same-Fund exchanges could include an exchange of one class for another with higher expenses. Before making such an exchange, you should consider the expenses of each class. Shareholders should contact their financial intermediaries to learn more about the details of the same-Fund exchange privilege. Exchanges out of Class A and Class C shares will be subject to any applicable CDSC. Financial intermediaries that have a customized arrangement with regard to CDSCs are detailed in Appendix A.

Exchanges out of Class C shares to another share class of the same Fund are not permissible on Direct-at-Fund Accounts, except that the Transfer Agent seeks to convert Class C shares as soon as administratively feasible to Class A shares of the same Fund for Direct-at-Fund Accounts that do not or no longer have a financial intermediary assigned to them. Direct-at-Fund Accounts that do not have a financial intermediary assigned to them are not permitted to purchase Class C shares. Class C share purchase orders received by Direct-at-Fund Accounts that do not have a financial intermediary assigned to the account will automatically be invested in Class A shares of the same Fund. Exchanges out of Class C shares to another share class of the same Fund within commissionable brokerage accounts are permitted only (1) when the shareholder moves from a commissionable brokerage account to a fee-based advisory program or (2) when the exchange is part of a share class conversion (or a similar multiple shareholder transaction event) instituted by a financial intermediary and such conversion or similar type event is preapproved by the Distributor.

Ordinarily, shareholders will not recognize a gain or loss for U.S. federal income tax purposes upon a same-Fund exchange. You should consult your tax advisor about your particular exchanges.

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Distributions and Taxes

Distributions to Shareholders

A mutual fund can make money two ways:

■ It can earn income on its investments. Examples of fund income are interest paid on money market instruments and bonds, and dividends paid on common stocks.

■ A mutual fund can also have capital gains if the value of its investments increases. While a fund continues to hold an investment, any gain is generally unrealized. If the fund sells an investment, it generally will realize a capital gain if it sells that investment for a higher price than its adjusted cost basis, and will generally realize a capital loss if it sells that investment for a lower price than its adjusted cost basis. Capital gains and losses are either short-term or long-term, depending on whether the fund holds the securities for one year or less (short-term) or more than one year (long-term).

Mutual funds make payments of fund earnings to shareholders, distributing them among all shareholders of the fund. As a shareholder, you are entitled to your portion of a fund's distributed income, including capital gains. Reinvesting your distributions buys you more shares of a fund — which lets you take advantage of the potential for compound growth. Putting the money you earn back into your investment means it, in turn, may earn even more money (or be exposed to additional losses, if the Fund earns a negative return). Over time, the power of compounding has the potential to significantly increase the value of your investment. There is no assurance, however, that you'll earn more money if you reinvest your distributions rather than receive them in cash.

The Fund intends to pay out, in the form of distributions to shareholders, a sufficient amount of its income and gains so that the Fund will qualify for treatment as a regulated investment company and generally will not have to pay any federal excise tax. The Fund generally intends to distribute any net realized capital gain (whether long-term or short-term gain) at least once a year. Normally, the Fund will declare and pay distributions of net investment income according to the following schedule:

Declaration and Distribution Schedule
Declarations	Semiannually
Distributions	Semiannually

The Fund may declare or pay distributions of net investment income more frequently.

Different share classes of the Fund usually pay different net investment income distribution amounts, because each class has different expenses. Each time a distribution is made, the NAV per share of the share class is reduced by the amount of the distribution.

The Fund generally pays cash distributions within five business days after the distribution was declared (or, if the Fund declares distributions daily, within five business days after the end of the month in which the distribution was declared). If you sell all of your shares after the record date, but before the payment date, for a distribution, you'll normally receive that distribution in cash within five business days after the sale was made.

The Fund will automatically reinvest distributions in additional shares of the same share class of the Fund unless you inform us you want to receive your distributions in cash (the financial intermediary through which you purchased shares may have different policies). You can do this by contacting the Funds at the addresses and telephone numbers listed at the beginning of the section entitled Choosing a Share Class. No sales charges apply to the purchase or sale of such shares.

For accounts held directly with the Fund (through the Transfer Agent), distributions of $10 or less will automatically be reinvested in additional Fund shares only. If you elect to receive distributions by check and the check is returned as undeliverable, all subsequent distributions will be reinvested in additional shares of the Fund.

Unless you are a tax-exempt investor or holding Fund shares through a tax-advantaged account (such as a 401(k) plan or IRA), you should consider avoiding buying Fund shares shortly before the Fund makes a distribution (other than distributions of net investment income that are declared daily) of net investment income or net realized capital gain, because doing so can cost you money in taxes to the extent the distribution consists of taxable income or gains. This is because you will, in effect, receive part of your purchase price back in the distribution. This is known as

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Distributions and Taxes (continued)

“buying a dividend.” To avoid “buying a dividend,” before you invest check the Fund's distribution schedule, which is available at the Funds' website and/or by calling the Funds' telephone number listed at the beginning of the section entitled Choosing a Share Class.

Taxes

You should be aware of the following considerations applicable to the Fund:

■ The Fund intends to qualify and to be eligible for treatment each year as a regulated investment company. A regulated investment company generally is not subject to tax at the fund level on income and gains from investments that are distributed to shareholders. However, the Fund's failure to qualify for treatment as a regulated investment company would result in Fund-level taxation, and consequently, a reduction in income available for distribution to you and in the NAV of your shares. Even if the Fund qualifies for treatment as a regulated investment company, the Fund may be subject to federal excise tax on certain undistributed income or gains.

■ Otherwise taxable distributions generally are taxable to you when paid, whether they are paid in cash or automatically reinvested in additional Fund shares. Dividends paid in January are deemed paid on December 31 of the prior year if the dividend was declared and payable to shareholders of record in October, November, or December of such prior year.

■ Distributions of the Fund's ordinary income and net short-term capital gain, if any, generally are taxable to you as ordinary income. Distributions of the Fund's net long-term capital gain, if any, generally are taxable to you as long-term capital gain. Whether capital gains are long-term or short-term is determined by how long the Fund has owned the investments that generated them, rather than how long you have owned your shares. Certain events may require the Fund to sell significant amounts of appreciated securities, and make large capital gain dividends relative to the Fund’s NAV. Such events may include large net shareholder redemptions, portfolio re-balancing or fund mergers. The Fund generally provides estimates of expected capital gain dividends (if any) prior to the distribution on columbiathreadneedleus.com.

■ From time to time, a distribution from the Fund could constitute a return of capital. A return of capital is a return of an amount of your original investment and is not a distribution of income or capital gain from the Fund. Therefore, a return of capital is not taxable to you so long as the amount of the distribution does not exceed your tax basis in your Fund shares. A return of capital reduces your tax basis in your Fund shares, with any amounts exceeding such basis generally taxable as capital gain.

■ If you are an individual and you meet certain holding period and other requirements for your Fund shares, a portion of your distributions may be treated as “qualified dividend income” taxable at the lower net long-term capital gain rates instead of the higher ordinary income rates. Qualified dividend income is income attributable to the Fund's dividends received from certain U.S. and foreign corporations, as long as the Fund meets certain holding period and other requirements for the stock producing such dividends.

■ Certain high-income individuals (as well as estates and trusts) are subject to a 3.8% tax on net investment income. For individuals, the 3.8% tax applies to the lesser of (1) the amount (if any) by which the taxpayer's modified adjusted gross income exceeds certain threshold amounts or (2) the taxpayer's “net investment income.”

■ Certain derivative instruments when held in the Fund's portfolio subject the Fund to special tax rules, the effect of which may be to, among other things, accelerate income to the Fund, defer Fund losses, cause adjustments in the holding periods of Fund portfolio securities, or convert capital gains into ordinary income, short-term capital losses into long-term capital losses or long-term capital gains into short-term capital gains. These rules could therefore affect the amount, timing and/or character of distributions to shareholders.

■ Generally, a Fund realizes a capital gain or loss on an option when the option expires, or when it is exercised, sold or otherwise terminated. However, if an option is a “section 1256 contract,” which includes most traded options on a broad-based index, and the Fund holds such option at the end of its taxable year, the Fund is deemed to sell such option at fair market value at such time and recognize any gain or loss thereon, which is generally deemed to be 60% long-term and 40% short-term capital gain or loss, as described further in the SAI.

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Distributions and Taxes (continued)

■ For a Fund organized as a fund-of-funds: Because most of the Fund's investments are shares of underlying Funds, the tax treatment of the Fund's gains, losses, and distributions may differ from the tax treatment that would apply if either the Fund invested directly in the types of securities held by the underlying Funds or the Fund shareholders invested directly in the underlying Funds. As a result, you may receive taxable distributions earlier and recognize higher amounts of capital gain or ordinary income than you otherwise would.

■ A sale, redemption or exchange of Fund shares is a taxable event. This includes redemptions where you are paid in securities. Your sales, redemptions and exchanges of Fund shares (including those paid in securities) usually will result in a taxable capital gain or loss to you, equal to the difference between the amount you receive for your shares (or are deemed to have received in the case of exchanges) and your adjusted tax basis in the shares, which is generally the amount you paid (or are deemed to have paid in the case of exchanges) for them. Any such capital gain or loss generally will be long-term capital gain or loss if you have held your Fund shares for more than one year at the time of sale or exchange. In certain circumstances, capital losses may be converted from short-term to long-term; in other circumstances, capital losses may be disallowed under the “wash sale” rules.

■ For sales, redemptions and exchanges of shares that were acquired in a non-qualified account after 2011, the Fund generally is required to report to shareholders and the Internal Revenue Service (IRS) cost basis information with respect to those shares. The Fund uses average cost basis as its default method of calculating cost basis. For more information regarding average cost basis reporting, other available cost basis methods, and selecting or changing to a different cost basis method, please see the SAI, columbiathreadneedleus.com, or contact the Fund at 800.345.6611. If you hold Fund shares through a financial intermediary (e.g., a brokerage firm), you should contact your financial intermediary to learn about its cost basis reporting default method and the reporting elections available to your account.

■ The Fund is required by federal law to withhold tax on any taxable or tax-exempt distributions and redemption proceeds paid to you (including amounts paid to you in securities and amounts deemed to be paid to you upon an exchange of shares) if: you have not provided a correct TIN or have not certified to the Fund that withholding does not apply, the IRS has notified us that the TIN listed on your account is incorrect according to its records, or the IRS informs the Fund that you are otherwise subject to backup withholding.

 FUNDamentals

Taxes

The information provided above is only a summary of how U.S. federal income taxes may affect your investment in the Fund. It is not intended as a substitute for careful tax planning. Your investment in the Fund may have other tax implications. It does not apply to certain types of investors who may be subject to special rules, including foreign or tax-exempt investors or those holding Fund shares through a tax-advantaged account, such as a 401(k) plan or IRA. Please see the SAI for more detailed tax information. You should consult with your own tax advisor about the particular tax consequences to you of an investment in the Fund, including the effect of any foreign, state and local taxes, and the effect of possible changes in applicable tax laws.

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Financial Highlights

The financial highlights table is intended to help you understand the Fund’s financial performance for the past five fiscal years. Certain information reflects financial results for a single Fund share. Per share net investment income (loss) amounts are calculated based on average shares outstanding during the period. The total return in the table represents the rate that an investor would have earned (or lost) on an investment in the Fund assuming all dividends and distributions had been reinvested. Total return does not reflect payment of sales charges, if any. Total return and portfolio turnover are not annualized for periods of less than one year. The portfolio turnover rate is calculated without regard to purchase and sales transactions of short-term instruments and certain derivatives, if any. If such transactions were included, the Fund’s portfolio turnover rate might be higher. The names of certain share classes may have changed during the periods shown below (see Appendix S to the SAI for details). This information has been audited by PricewaterhouseCoopers LLP, an independent registered public accounting firm, whose report, along with the Fund’s financial statements, is included in the Fund’s annual report, which is available upon request. The independent registered public accounting firm’s report and the Fund’s financial statements are also incorporated by reference into the SAI.

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Financial Highlights (continued)

	Net asset value, beginning of period	Net investment income	Net realized and unrealized gain (loss)	Total from investment operations	Distributions from net investment income	Distributions from net realized gains	Total distributions to shareholders
Class A
Year Ended 12/31/2021	$18.31	0.24	0.89	1.13	(0.26)	(2.17)	(2.43)
Year Ended 12/31/2020	$15.12	0.26	4.13	4.39	(0.27)	(0.93)	(1.20)
Year Ended 12/31/2019	$13.85	0.27	1.79	2.06	(0.26)	(0.53)	(0.79)
Year Ended 12/31/2018	$14.63	0.24	(0.26)	(0.02)	(0.28)	(0.48)	(0.76)
Year Ended 12/31/2017	$14.60	0.25	0.50	0.75	(0.50)	(0.22)	(0.72)
Advisor Class
Year Ended 12/31/2021	$18.12	0.28	0.88	1.16	(0.30)	(2.17)	(2.47)
Year Ended 12/31/2020	$14.97	0.36	4.04	4.40	(0.32)	(0.93)	(1.25)
Year Ended 12/31/2019	$13.72	0.31	1.77	2.08	(0.30)	(0.53)	(0.83)
Year Ended 12/31/2018	$14.50	0.28	(0.27)	0.01	(0.31)	(0.48)	(0.79)
Year Ended 12/31/2017	$14.47	0.29	0.50	0.79	(0.54)	(0.22)	(0.76)
Class C
Year Ended 12/31/2021	$18.43	0.09	0.90	0.99	(0.11)	(2.17)	(2.28)
Year Ended 12/31/2020	$15.23	0.12	4.16	4.28	(0.15)	(0.93)	(1.08)
Year Ended 12/31/2019	$13.96	0.16	1.79	1.95	(0.15)	(0.53)	(0.68)
Year Ended 12/31/2018	$14.74	0.13	(0.26)	(0.13)	(0.17)	(0.48)	(0.65)
Year Ended 12/31/2017	$14.62	0.14	0.51	0.65	(0.31)	(0.22)	(0.53)
Institutional Class
Year Ended 12/31/2021	$18.01	0.28	0.87	1.15	(0.30)	(2.17)	(2.47)
Year Ended 12/31/2020	$14.88	0.31	4.07	4.38	(0.32)	(0.93)	(1.25)
Year Ended 12/31/2019	$13.65	0.30	1.76	2.06	(0.30)	(0.53)	(0.83)
Year Ended 12/31/2018	$14.43	0.28	(0.27)	0.01	(0.31)	(0.48)	(0.79)
Year Ended 12/31/2017	$14.40	0.29	0.50	0.79	(0.54)	(0.22)	(0.76)
Institutional 2 Class
Year Ended 12/31/2021	$18.14	0.29	0.89	1.18	(0.31)	(2.17)	(2.48)
Year Ended 12/31/2020	$14.99	0.31	4.09	4.40	(0.32)	(0.93)	(1.25)
Year Ended 12/31/2019	$13.74	0.32	1.77	2.09	(0.31)	(0.53)	(0.84)
Year Ended 12/31/2018	$14.52	0.29	(0.27)	0.02	(0.32)	(0.48)	(0.80)
Year Ended 12/31/2017	$14.49	0.29	0.50	0.79	(0.54)	(0.22)	(0.76)

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Financial Highlights (continued)

	Net asset value, end of period	Total return(a)	Total gross expense ratio to average net assets(b)	Total net expense ratio to average net assets(b)	Net investment income ratio to average net assets	Portfolio turnover	Net assets, end of period (000's)
Class A
Year Ended 12/31/2021	$17.01	6.16%	0.54% (c)	0.50% (c), (d)	1.26%	49%	$624,373
Year Ended 12/31/2020	$18.31	29.27%	0.56% (c)	0.50% (c), (d)	1.53%	97%	$505,238
Year Ended 12/31/2019	$15.12	14.94%	0.58% (c)	0.50% (c), (d)	1.81%	158%	$225,113
Year Ended 12/31/2018	$13.85	(0.13%)	0.56%	0.50% (d)	1.66%	122%	$193,683
Year Ended 12/31/2017	$14.63	5.19%	0.54%	0.50% (d)	1.70%	33%	$257,752
Advisor Class
Year Ended 12/31/2021	$16.81	6.43%	0.29% (c)	0.25% (c), (d)	1.51%	49%	$172,162
Year Ended 12/31/2020	$18.12	29.58%	0.32% (c)	0.25% (c), (d)	2.04%	97%	$130,921
Year Ended 12/31/2019	$14.97	15.21%	0.33% (c)	0.25% (c), (d)	2.08%	158%	$16,208
Year Ended 12/31/2018	$13.72	0.12%	0.31%	0.25% (d)	1.91%	122%	$11,816
Year Ended 12/31/2017	$14.50	5.49%	0.29%	0.25% (d)	1.98%	33%	$16,227
Class C
Year Ended 12/31/2021	$17.14	5.40%	1.29% (c)	1.25% (c), (d)	0.48%	49%	$189,990
Year Ended 12/31/2020	$18.43	28.28%	1.31% (c)	1.25% (c), (d)	0.72%	97%	$208,937
Year Ended 12/31/2019	$15.23	14.02%	1.33% (c)	1.25% (c), (d)	1.05%	158%	$156,027
Year Ended 12/31/2018	$13.96	(0.88%)	1.31%	1.25% (d)	0.90%	122%	$166,292
Year Ended 12/31/2017	$14.74	4.48%	1.29%	1.25% (d)	0.96%	33%	$250,784
Institutional Class
Year Ended 12/31/2021	$16.69	6.42%	0.29% (c)	0.25% (c), (d)	1.52%	49%	$902,841
Year Ended 12/31/2020	$18.01	29.63%	0.31% (c)	0.25% (c), (d)	1.80%	97%	$729,119
Year Ended 12/31/2019	$14.88	15.14%	0.33% (c)	0.25% (c), (d)	2.06%	158%	$285,444
Year Ended 12/31/2018	$13.65	0.12%	0.31%	0.25% (d)	1.91%	122%	$253,123
Year Ended 12/31/2017	$14.43	5.52%	0.29%	0.25% (d)	1.97%	33%	$320,483
Institutional 2 Class
Year Ended 12/31/2021	$16.84	6.53%	0.25% (c)	0.20% (c)	1.53%	49%	$169,246
Year Ended 12/31/2020	$18.14	29.59%	0.27% (c)	0.21% (c)	1.82%	97%	$129,197
Year Ended 12/31/2019	$14.99	15.25%	0.28% (c)	0.21% (c)	2.16%	158%	$40,759
Year Ended 12/31/2018	$13.74	0.16%	0.26%	0.21%	1.97%	122%	$16,478
Year Ended 12/31/2017	$14.52	5.51%	0.26%	0.23%	1.97%	33%	$13,464

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Financial Highlights (continued)

	Net asset value, beginning of period	Net investment income	Net realized and unrealized gain (loss)	Total from investment operations	Distributions from net investment income	Distributions from net realized gains	Total distributions to shareholders
Institutional 3 Class
Year Ended 12/31/2021	$18.11	0.36	0.82	1.18	(0.32)	(2.17)	(2.49)
Year Ended 12/31/2020	$14.96	0.33	4.08	4.41	(0.33)	(0.93)	(1.26)
Year Ended 12/31/2019	$13.72	0.32	1.76	2.08	(0.31)	(0.53)	(0.84)
Year Ended 12/31/2018	$14.50	0.30	(0.27)	0.03	(0.33)	(0.48)	(0.81)
Year Ended 12/31/2017	$14.46	0.30	0.51	0.81	(0.55)	(0.22)	(0.77)

Notes to Financial Highlights
(a)	Had the Investment Manager and/or Transfer Agent not waived fees and/or reimbursed a portion of expenses, total return would have been reduced.
(b)	In addition to the fees and expenses that the Fund bears directly, the Fund indirectly bears a pro rata share of the fees and expenses of any other funds in which it invests, if any. Such indirect expenses are not included in the Fund's reported expense ratios.
(c)	Ratios include line of credit interest expense which is less than 0.01%.
(d)	The benefits derived from expense reductions had an impact of less than 0.01%.

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Financial Highlights (continued)

	Net asset value, end of period	Total return(a)	Total gross expense ratio to average net assets(b)	Total net expense ratio to average net assets(b)	Net investment income ratio to average net assets	Portfolio turnover	Net assets, end of period (000's)
Institutional 3 Class
Year Ended 12/31/2021	$16.80	6.52%	0.21% (c)	0.17% (c)	1.94%	49%	$15,581
Year Ended 12/31/2020	$18.11	29.69%	0.24% (c)	0.17% (c)	1.89%	97%	$2,862
Year Ended 12/31/2019	$14.96	15.24%	0.25% (c)	0.16% (c)	2.13%	158%	$837
Year Ended 12/31/2018	$13.72	0.21%	0.22%	0.16%	2.04%	122%	$461
Year Ended 12/31/2017	$14.50	5.64%	0.21%	0.18%	2.04%	33%	$521

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Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges

As noted in the Choosing a Share Class section of the prospectus, the sales charge reductions and waivers available to investors who purchase and hold their Fund shares through different financial intermediaries may vary. This Appendix A describes financial intermediary-specific reductions and/or waiver policies applicable to Fund shares purchased and held through the particular financial intermediary. A reduction and/or waiver that is specific to a particular financial intermediary is not available to Direct-at-Fund Accounts and does not apply in any case to non-omnibus positions wherever held. These reductions and/or waivers may apply to purchases, sales, and exchanges of Fund shares. A shareholder transacting in Fund shares through a financial intermediary identified below should carefully read the terms and conditions of the reductions and/or waivers. Please consult your financial intermediary with respect to any sales charge reduction/waiver described below.

The financial intermediary-specific information below may be provided by, or compiled from or based on information provided by, the financial intermediaries noted. While the Funds, the Investment Manager and the Distributor do not establish these financial intermediary-specific policies, our representatives are available to answer questions about these financial intermediary-specific policies and can direct you to the financial intermediary if you need help understanding them.

 Ameriprise Financial Services, LLC (Ameriprise Financial Services)

The following information has been provided by Ameriprise Financial Services:

Class A Shares Front-End Sales Charge Waivers Available at Ameriprise Financial Services:

The following information applies to Class A shares purchases if you have an account with or otherwise purchase Fund shares through Ameriprise Financial Services:

Shareholders purchasing Fund shares through an Ameriprise Financial Services brokerage account are eligible for the following front-end sales charge waivers, which may differ from those disclosed elsewhere in this prospectus or the Fund’s SAI:

■ Employer-sponsored retirement plans (e.g., 401(k) plans, 457 plans, employer-sponsored 403(b) plans, profit sharing and money purchase pension plans and defined benefit plans). For purposes of this provision, employer-sponsored retirement plans do not include SEP IRAs, Simple IRAs or SAR-SEPs.

■ Shares purchased through reinvestment of capital gains distributions and dividend reinvestment when purchasing shares of the same fund (but not any other fund within the Columbia Fund family).

■ Shares exchanged from Class C shares of the same fund in the month of or following the 7-year anniversary of the purchase date. To the extent that the Fund’s Class C Shares – Conversion to Class A Shares policy (stated outside this Appendix A) provides for a waiver with respect to exchanges of Class C shares or the conversion of Class C shares following a shorter holding period, that waiver will apply.

■ Employees and registered representatives of Ameriprise Financial Services or its affiliates and their immediate family members.

■ Shares purchased by or through qualified accounts (including IRAs, Coverdell Education Savings Accounts, 401(k)s, 403(b) TSCAs subject to ERISA and defined benefit plans) that are held by a covered family member, defined as an Ameriprise financial advisor and/or the advisor’s spouse, advisor’s lineal ascendant (mother, father, grandmother, grandfather, great grandmother, great grandfather), advisor’s lineal descendant (son, step-son, daughter, step-daughter, grandson, granddaughter, great grandson, great granddaughter) or any spouse of a covered family member who is a lineal descendant.

■ Shares purchased from the proceeds of redemptions from another fund in the Columbia Fund family, provided (1) the repurchase occurs within 90 days following the redemption, (2) the redemption and purchase occur in the same account, and (3) redeemed shares were subject to a front-end or deferred sales load (i.e. Rights of Reinstatement).

A-1 Prospectus 2022

Columbia Thermostat Fund^SM

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

 Robert W. Baird & Co. Incorporated (Baird)

The following information has been provided by Baird:

Effective June 30, 2020, shareholders purchasing Columbia Fund shares through a Baird platform or account that maintains an omnibus position with the Fund will only be eligible for the following sales charge waivers (front-end sales charge waivers and CDSC waivers) and discounts, which may differ from those disclosed elsewhere in this prospectus or the Fund’s SAI. A reduction and/or waiver that is specific to Baird will not apply to non-omnibus positions.

Front-End Sales Charge Waivers on Class A Shares Available at Baird:

■ Shares purchased through reinvestment of capital gains distributions and dividend reinvestment when purchasing shares of the same Columbia Fund.

■ Share purchases by employees and registered representatives of Baird or its affiliates and their family members as designated by Baird.

■ Shares purchased with the proceeds of redemptions from another Columbia Fund, provided (1) the repurchase occurs within 90 days following the redemption, (2) the redemption and purchase occur in the same accounts, and (3) redeemed shares were subject to a front-end or deferred sales charge (known as rights of reinstatement).

■ A shareholder in the Fund’s Class C shares will have their shares converted at net asset value to Class A shares of the same Columbia Fund if the shares are no longer subject to CDSC and the conversion is in line with the policies and procedures of Baird.

■ Employer-sponsored retirement plans or charitable accounts in a transactional brokerage account at Baird, including 401(k) plans, 457 plans, employer-sponsored 403(b) plans, profit sharing and money purchase pension plans and defined benefit plans. For purposes of this provision, employer-sponsored retirement plans do not include SEP IRAs, Simple IRAs or SAR-SEPs.

CDSC Waivers on Class A and Class C Shares Available at Baird:

■ Shares sold due to death or disability of the shareholder.

■ Shares sold as part of a systematic withdrawal plan as described in this prospectus.

■ Shares purchased due to returns of excess contributions from an IRA account.

■ Shares sold as part of a required minimum distribution for IRA and retirement accounts due to the shareholder reaching the qualified age based on applicable IRS regulations.

■ Shares sold to pay Baird fees but only if the transaction is initiated by Baird.

■ Shares acquired through a right of reinstatement.

Front-End Sales Charge Discounts Available at Baird: Breakpoints and/or Rights of Accumulations:

■ Breakpoints as described in this prospectus.

■ Rights of accumulations which entitle shareholders to breakpoint discounts will be automatically calculated based on the aggregated holding of Columbia Fund assets held by accounts within the purchaser’s household at Baird. Eligible Columbia Fund assets not held at Baird may be included in the rights of accumulations calculation only if the shareholder notifies his or her financial advisor about such assets.

■ Letters of Intent (LOI) allow for breakpoint discounts based on anticipated purchases of Columbia Funds through Baird, over a 13-month period of time.

Prospectus 2022 A-2

Columbia Thermostat Fund^SM

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

 Edward D. Jones & Co., L.P. (Edward Jones)

Policies Regarding Transactions Through Edward Jones

The following information has been provided by Edward Jones:

Effective on or after January 15, 2021, the following information supersedes prior information with respect to transactions and positions held in Columbia Fund shares through an Edward Jones system. Clients of Edward Jones (also referred to as "shareholders") purchasing Columbia Fund shares on the Edward Jones commission and fee-based platforms are eligible only for the following sales charge discounts (also referred to as "breakpoints") and waivers, which can differ from discounts and waivers described elsewhere in this prospectus or the Fund’s SAI or through another broker-dealer. In all instances, it is the shareholder's responsibility to inform Edward Jones at the time of purchase of any relationship, holdings of Columbia Funds and Future Scholars Program, or other facts qualifying the purchaser for discounts or waivers. Edward Jones can ask for documentation of such circumstance. Shareholders should contact Edward Jones if they have questions regarding their eligibility for these discounts and waivers.

Breakpoints

■ Breakpoint pricing, otherwise known as volume pricing, at dollar thresholds as described in this prospectus.

Rights of Accumulation (ROA)

■ The applicable sales charge on a purchase of Class A shares is determined by taking into account all share classes (except certain money market funds and any assets held in group retirement plans) of Columbia Funds and Future Scholars Program held by the shareholder or in an account grouped by Edward Jones with other accounts for the purpose of providing certain pricing considerations ("pricing groups"). If grouping assets as a shareholder, this includes all share classes held on the Edward Jones platform and/or held on another platform. The inclusion of eligible Columbia Fund assets in the ROA calculation is dependent on the shareholder notifying Edward Jones of such assets at the time of calculation. Money market funds are included only if such shares were sold with a sales charge at the time of purchase or acquired in exchange for shares purchased with a sales charge.

■ The employer maintaining a SEP IRA plan and/or SIMPLE IRA plan may elect to establish or change ROA for the IRA accounts associated with the plan to a plan-level grouping as opposed to including all share classes at a shareholder or pricing group level.

■ ROA is determined by calculating the higher of cost minus redemptions or market value (current shares x NAV).

Letter of Intent (LOI)

■ Through a LOI, shareholders can receive the sales charge and breakpoint discounts for purchases shareholders intend to make over a 13-month period from the date Edward Jones receives the LOI. The LOI is determined by calculating the higher of cost or market value of qualifying holdings at LOI initiation in combination with the value that the shareholder intends to buy over a 13-month period to calculate the front-end sales charge and any breakpoint discounts. Each purchase the shareholder makes during that 13-month period will receive the sales charge and breakpoint discount that applies to the total amount. The inclusion of eligible Columbia Fund assets in the LOI calculation is dependent on the shareholder notifying Edward Jones of such assets at the time of calculation. Purchases made before the LOI is received by Edward Jones are not adjusted under the LOI and will not reduce the sales charge previously paid. Sales charges will be adjusted if LOI is not met.

■ If the employer maintaining a SEP IRA plan and/or SIMPLE IRA plan has elected to establish or change ROA for the IRA accounts associated with the plan to a plan-level grouping, LOIs will also be at the plan-level and may only be established by the employer.

A-3 Prospectus 2022

Columbia Thermostat Fund^SM

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

Sales Charge Waivers

Sales charges are waived for the following shareholders and in the following situations:

■ Associates of Edward Jones and its affiliates and their family members who are in the same pricing group (as determined by Edward Jones under its policies and procedures) as the associate. This waiver will continue for the remainder of the associate's life if the associate retires from Edward Jones in good-standing and remains in good standing pursuant to Edward Jones' policies and procedures.

■ Shares purchased in an Edward Jones fee-based program.

■ Shares purchased through reinvestment of capital gains distributions and dividend reinvestment.

■ Shares purchased from the proceeds of redeemed shares of Columbia Funds so long as the following conditions are met: 1) the proceeds are from the sale of shares within 60 days of the purchase, and 2) the sale and purchase are made in the same share class and the same account or the purchase is made in an individual retirement account with proceeds from liquidations in a non-retirement account.

■ Shares exchanged into Class A shares from another share class so long as the exchange is into the same fund and was initiated at the discretion of Edward Jones. Edward Jones is responsible for any remaining CDSC due to the fund company, if applicable. Any future purchases are subject to the applicable sales charge as disclosed in this prospectus.

■ Exchanges from Class C shares to Class A shares of the same fund, generally, in the 84th month following the anniversary of the purchase date or earlier at the discretion of Edward Jones.

Contingent Deferred Sales Charge (CDSC) Waivers

If the shareholder purchases shares that are subject to a CDSC and those shares are redeemed before the CDSC is expired, the shareholder is responsible to pay the CDSC except in the following conditions:

■ The death or disability of the shareholder.

■ Systematic withdrawals with up to 10% per year of the account value.

■ Return of excess contributions from an Individual Retirement Account (IRA).

■ Shares sold as part of a required minimum distribution for IRA and retirement accounts if the redemption is taken in or after the year the shareholder reaches qualified age based on applicable IRS regulations.

■ Shares sold to pay Edward Jones fees or costs in such cases where the transaction is initiated by Edward Jones.

■ Shares exchanged in an Edward Jones fee-based program.

■ Shares acquired through NAV reinstatement.

■ Shares redeemed at the discretion of Edward Jones for Minimum Balances, as described below.

Other Important Information Regarding Transactions Through Edward Jones

Minimum Purchase Amounts

■ Initial purchase minimum: $250

■ Subsequent purchase minimum: none

Minimum Balances

■ Edward Jones has the right to redeem at its discretion Fund holdings with a balance of $250 or less. The following are examples of accounts that are not included in this policy:

■ A fee-based account held on an Edward Jones platform.

■ A 529 account held on an Edward Jones platform.

■ An account with an active systematic investment plan or LOI.

Prospectus 2022 A-4

Columbia Thermostat Fund^SM

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

Exchanging Share Classes

■ At any time it deems necessary, Edward Jones has the authority to exchange at NAV a shareholder's holdings in the Fund to Class A shares.

 Janney Montgomery Scott LLC (Janney)

The following information has been provided by Janney:

Effective May 1, 2020, if you purchase Columbia Fund shares through a Janney brokerage account, you will be eligible for the following load waivers (front-end sales charge waivers and CDSC, or back-end sales charge, waivers) and discounts, which may differ from those disclosed elsewhere in this prospectus or the Fund’s SAI. A reduction and/or waiver that is specific to Janney does not apply to non-omnibus positions.

Front-End Sales Charge* Waivers on Class A Shares Available at Janney

■ Shares purchased through reinvestment of capital gains distributions and dividend reinvestment when purchasing shares of the same fund (but not any other Columbia Fund).

■ Shares purchased by employees and registered representatives of Janney or its affiliates and their family members as designated by Janney.

■ Shares purchased from the proceeds of redemptions from another Columbia Fund, provided (1) the repurchase occurs within ninety (90) days following the redemption, (2) the redemption and purchase occur in the same account, and (3) redeemed shares were subject to a front-end or deferred sales load (i.e., right of reinstatement).

■ Employer-sponsored retirement plans (e.g., 401(k) plans, 457 plans, employer-sponsored 403(b) plans, profit sharing and money purchase pension plans and defined benefit plans). For purposes of this provision, employer-sponsored retirement plans do not include SEP IRAs, Simple IRAs, SAR-SEPs or Keogh plans.

■ Shares acquired through a right of reinstatement.

■ Class C shares that are no longer subject to a CDSC and are converted to Class A shares of the same fund pursuant to Janney’s policies and procedures.

CDSC Waivers on Class A and C Shares Available at Janney

■ Shares sold upon the death or disability of the shareholder.

■ Shares sold as part of a systematic withdrawal plan as described in this prospectus.

■ Shares purchased in connection with a return of excess contributions from an IRA account.

■ Shares sold as part of a required minimum distribution for IRA and retirement accounts if the redemption is taken in or after the year the shareholder reaches qualified age based on applicable IRS regulations.

■ Shares sold to pay Janney fees but only if the transaction is initiated by Janney.

■ Shares acquired through a right of reinstatement.

■ Shares exchanged into the same share class of a different fund.

Front-End Sales Charge* Discounts Available at Janney: Breakpoints, Rights of Accumulation, and/or Letters of Intent

■ Breakpoints as described in this prospectus.

■ Rights of accumulation (“ROA”), which entitle shareholders to breakpoint discounts, will be automatically calculated based on the aggregated holding of Columbia Fund assets held by accounts within the purchaser’s household at Janney. Eligible Columbia Fund assets not held at Janney may be included in the ROA calculation only if the shareholder notifies his or her financial advisor about such assets.

■ Letters of intent which allow for breakpoint discounts based on anticipated purchases within the Columbia Funds, over a 13-month time period. Eligible Columbia Fund assets not held at Janney may be included in the calculation of letters of intent only if the shareholder notifies his or her financial advisor about such assets.

A-5 Prospectus 2022

Columbia Thermostat Fund^SM

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

* Also referred to as an “initial sales charge”.

 Merrill Lynch Pierce, Fenner & Smith Incorporated (Merrill Lynch)

The following information has been provided by Merrill Lynch:

Shareholders purchasing Columbia Fund shares through a Merrill Lynch platform or account will be eligible only for the following load waivers (front-end sales charge waivers and contingent deferred, or back-end, sales charge waivers) and discounts, which may differ from those disclosed elsewhere in this prospectus or the Fund’s SAI:

Front-End Load Discounts Available at Merrill Lynch:

Merrill Lynch makes available breakpoint discounts on shares of the Fund through:

■ Breakpoints as described in this prospectus.

■ Rights of Accumulation (ROA) which entitle shareholders to breakpoint discounts as described in this prospectus will be automatically calculated based on the aggregated holding of Columbia Fund assets held by accounts (including 529 program holdings, where applicable) within the purchaser’s household at Merrill Lynch. Eligible Columbia Fund assets not held at Merrill Lynch may be included in the ROA calculation only if the shareholder notifies his or her financial advisor about such assets.

■ Letters of Intent (LOI) which allow for breakpoint discounts based on anticipated purchases of Columbia Funds, through Merrill Lynch, over a 13-month period of time (if applicable).

Front-End Sales Load Waivers on Class A Shares Available at Merrill Lynch:

■ Employer-sponsored retirement, deferred compensation and employee benefit plans (including health savings accounts) and trusts used to fund those plans, provided that the shares are not held in a commission-based brokerage account and shares are held for the benefit of the plan.

■ Shares purchased by a 529 Plan (does not include 529 Plan units or 529-specific share classes or equivalents).

■ Shares purchased through a Merrill Lynch affiliated investment advisory program.

■ Shares exchanged due to the holdings moving from a Merrill Lynch affiliated investment advisory program to a Merrill Lynch brokerage (non-advisory) account pursuant to Merrill Lynch’s policies relating to sales load discounts and waivers.

■ Shares purchased by third party investment advisors on behalf of their advisory clients through Merrill Lynch’s platform.

■ Shares of funds purchased through the Merrill Edge Self-Directed platform (if applicable).

■ Shares purchased through reinvestment of capital gains distributions and dividend reinvestment when purchasing shares of the same fund (but not any other Columbia Fund).

■ Shares exchanged from Class C (i.e., level-load) shares of the same fund pursuant to Merrill Lynch’s policies relating to sales load discounts and waivers.

■ Employees and registered representatives of Merrill Lynch or its affiliates and their family members.

■ Directors or Trustees of the Fund, and employees of the Fund’s investment adviser or any of its affiliates, as described in this prospectus.

■ Eligible shares purchased from the proceeds of redemptions from another Columbia Fund, provided (1) the repurchase occurs within 90 days following the redemption, (2) the redemption and purchase occur in the same account, and (3) redeemed shares were subject to a front-end or deferred sales load (known as Rights of Reinstatement). Automated transactions (i.e. systematic purchases and withdrawals) and purchases made after shares are automatically sold to pay Merrill Lynch’s account maintenance fees are not eligible for reinstatement.

CDSC Waivers on Class A and C Shares Available at Merrill Lynch:

■ Death or disability of the shareholder.

Prospectus 2022 A-6

Columbia Thermostat Fund^SM

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

■ Shares sold as part of a systematic withdrawal plan as described in this prospectus.

■ Return of excess contributions from an IRA Account.

■ Shares sold as part of a required minimum distribution for IRA and retirement accounts pursuant to the Internal Revenue Code.

■ Shares sold to pay Merrill Lynch fees but only if the transaction is initiated by Merrill Lynch.

■ Shares acquired through a right of reinstatement.

■ Shares held in retirement brokerage accounts, that are exchanged for a lower cost share class due to transfer to certain fee based accounts or platforms (applicable to Class A and Class C shares only).

■ Shares received through an exchange due to the holdings moving from a Merrill Lynch affiliated investment advisory program to a Merrill Lynch brokerage (non-advisory) account pursuant to Merrill Lynch’s policies relating to sales load discounts and waivers.

 Morgan Stanley Smith Barney, LLC (Morgan Stanley Wealth Management)

The following information has been provided by Morgan Stanley Wealth Management:

Effective July 1, 2018, shareholders purchasing Columbia Fund shares through a Morgan Stanley Wealth Management transactional brokerage account will be eligible only for the following front-end sales charge waivers with respect to Class A shares, which may differ from and may be more limited than those disclosed elsewhere in this prospectus or the Fund’s SAI.

Front-End Sales Charge Waivers on Class A Shares Available at Morgan Stanley Wealth Management Effective July 1, 2018:

■ Employer-sponsored retirement plans (e.g., 401(k) plans, 457 plans, employer-sponsored 403(b) plans, profit sharing and money purchase pension plans and defined benefit plans).  For purposes of this provision, employer-sponsored retirement plans do not include SEP IRAs, Simple IRAs, SAR-SEPs or Keogh plans.

■ Morgan Stanley employee and employee-related accounts according to Morgan Stanley’s account linking rules.

■ Shares purchased through reinvestment of dividends and capital gains distributions when purchasing shares of the same fund.

■ Shares purchased through a Morgan Stanley self-directed brokerage account.

■ Class C (i.e., level-load) shares that are no longer subject to a CDSC and are exchanged for Class A shares of the same fund pursuant to Morgan Stanley Wealth Management’s share class exchange program.

■ Shares purchased from the proceeds of redemptions from another Columbia Fund, provided (i) the repurchase occurs within 90 days following the redemption, (ii) the redemption and purchase occur in the same account, and (iii) redeemed shares were subject to a front-end or deferred sales charge.

 Raymond James & Associates, Inc., Raymond James Financial Services, Inc. and each entity’s affiliates (Raymond James)

The following information has been provided by Raymond James:

Intermediary-Defined Sales Charge Waiver Policies:

The availability of certain initial or deferred sales charge waivers and discounts may depend on the particular financial intermediary or type of account through which you purchase or hold Columbia Fund shares.

Intermediaries may have different policies and procedures regarding the availability of front-end sales load waivers or contingent deferred (back-end) sales load (CDSC) waivers, which are discussed below. In all instances, it is the purchaser’s responsibility to notify the Fund or the purchaser’s financial intermediary at the time of purchase of any

A-7 Prospectus 2022

Columbia Thermostat Fund^SM

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

relationship or other facts qualifying the purchaser for sales charge waivers or discounts. For waivers and discounts not available through a particular intermediary, shareholders will have to purchase Columbia Fund shares directly from the Fund or through another intermediary to receive these waivers or discounts.

Raymond James:

Effective March 1, 2019, shareholders purchasing Columbia Fund shares through a Raymond James platform or account, or through an introducing broker-dealer or independent registered investment adviser for which Raymond James provides trade execution, clearance, and/or custody services, will be eligible only for the following load waivers (front-end sales charge waivers and contingent deferred, or back-end, sales charge waivers) and discounts, which may differ from those disclosed elsewhere in this prospectus or the Fund’s SAI.

Front-End Sales Load Waivers on Class A Shares Available at Raymond James:

■ Shares purchased in an investment advisory program.

■ Shares purchased within the Columbia Funds through a systematic reinvestment of capital gains and dividend distributions.

■ Employees and registered representatives of Raymond James or its affiliates and their family members as designated by Raymond James.

■ Shares purchased from the proceeds of redemptions within the Columbia Funds, provided (1) the repurchase occurs within 90 days following the redemption, (2) the redemption and purchase occur in the same account, and (3) redeemed shares were subject to a front-end or deferred sales load (known as Rights of Reinstatement).

■ A shareholder in the Fund’s Class C shares will have their shares converted at net asset value to Class A shares (or the appropriate share class) of the Fund if the shares are no longer subject to a CDSC and the conversion is in line with the policies and procedures of Raymond James.

CDSC Waivers on Class A and Class C Shares Available at Raymond James:

■ Death or disability of the shareholder.

■ Shares sold as part of a systematic withdrawal plan as described in this prospectus.

■ Return of excess contributions from an IRA Account.

■ Shares sold as part of a required minimum distribution for IRA and retirement accounts due to the shareholder reaching the qualified age based on applicable IRS regulations as described in this prospectus.

■ Shares sold to pay Raymond James fees but only if the transaction is initiated by Raymond James.

■ Shares acquired through a right of reinstatement.

Front-End Load Discounts Available at Raymond James: Breakpoints, Rights of Accumulation and/or Letters of Intent:

■ Breakpoints as described in this prospectus.

■ Rights of accumulation which entitle shareholders to breakpoint discounts will be automatically calculated based on the aggregated holding of Columbia Fund assets held by accounts within the purchaser’s household at Raymond James. Eligible Columbia Fund assets not held at Raymond James may be included in the calculation of rights of accumulation only if the shareholder notifies his or her financial advisor about such assets.

■ Letters of intent which allow for breakpoint discounts based on anticipated purchases within the Columbia Funds, over a 13-month time period. Eligible Columbia Fund assets not held at Raymond James may be included in the calculation of letters of intent only if the shareholder notifies his or her financial advisor about such assets.

 Stifel Financial Corp. (Stifel)

The following information has been provided by Stifel:

Prospectus 2022 A-8

Columbia Thermostat Fund^SM

Appendix A: Financial Intermediary-Specific Reductions/Waivers of Sales Charges (continued)

Effective June 30, 2020, Class C shares of Columbia Funds that were purchased through a Stifel platform or account that maintains an omnibus position with the Fund that are no longer subject to a CDSC are exchanged to Class A shares of the same Columbia Fund pursuant to Stifel’s policies and procedures. This does not apply to non-omnibus positions.

 U.S. Bancorp Investments, Inc. (USBI)

The following information has been provided by USBI:

Effective September of 2021, shareholders purchasing Columbia Fund shares through a USBI platform or who own shares for which USBI is the broker-dealer, where the shares are held in an omnibus account, will only be eligible for the following front-end sales charge waivers and discounts, which may differ from those disclosed elsewhere in this prospectus or the Fund’s SAI.

All other sales charge waivers and reduction described elsewhere in this prospectus or the Fund’s SAI still apply.

USBI Conversion of Class C shares

Class C (i.e., level-load) shares that are no longer subject to a contingent deferred sales charge are systematically converted to the Class A shares of the same fund pursuant to USBI’s share class exchange policy.

 Additional Sales Charge Reductions and/or Waivers Available at Certain Financial Intermediaries

Shareholders purchasing Columbia Fund shares through a platform or account of RBC Capital Markets, LLC are eligible for the following sales charge waiver:

Class A Shares Front-End Sales Charge Waiver Available at RBC Capital Markets, LLC:

■ For employer-sponsored retirement plans held through a commissionable brokerage account, Class A shares are available at NAV (i.e., without a sales charge). For this purpose, employer-sponsored retirement plans include, but are not limited to, 401(k) plans, 457 plans, employer-sponsored 403(b) plans, profit sharing and money purchase pension plans and defined benefit plans. For purposes of this provision, employer-sponsored retirement plans do not include SEP IRAs, Simple IRAs, SAR-SEPs or Keogh plans.

A-9 Prospectus 2022

[This page intentionally left blank]

Columbia Thermostat Fund^SM

P.O. Box 219104
Kansas City, MO 64121-9104

Columbia Acorn Family of Funds

Additional Information About the Fund

Additional information about the Fund’s investments is available in the Fund’s annual and semiannual reports to shareholders. In the annual report, you will find a discussion of the market conditions and investment strategies that significantly affected the Fund’s performance during its last fiscal year. The SAI also provides additional information about the Fund and its policies. The SAI, which has been filed with the SEC, is legally part of this prospectus (incorporated by reference). To obtain these documents free of charge, to request other information about the Fund and to make shareholder inquiries, please contact the Fund as follows:

By Mail:  Columbia Management Investment Services Corp.
P.O. Box 219104
Kansas City, MO 64121-9104

By Telephone: 800.345.6611

Online: columbiathreadneedleus.com

Shareholder Communications with the Board

The Fund’s Board of Trustees has adopted procedures by which shareholders may communicate with the Board. Shareholders who wish to communicate with the Board should send their written communications to the Board by mail, c/o Columbia Wanger Asset Management, LLC, 71 S. Wacker Drive, Suite 2500, Chicago, IL 60606, Attention: Secretary. Shareholder communications must (i) be in writing, (ii) identify the Columbia Acorn Fund to which the communication relates and (iii) state the particular class of shares and number of shares held by the communicating shareholder.

Obtaining Additional Information from the SEC

Reports and other information about the Fund are also available in the EDGAR Database on the SEC’s website at http://www.sec.gov. You can receive copies of this information, for a duplication fee, by electronic request at the following e-mail address: publicinfo@sec.gov.

The investment company registration number of Columbia Acorn Trust, of which the Fund is a series, is 811-01829.

Columbia Threadneedle Investments is the global brand name of the Columbia and Threadneedle group of companies.
The Fund is distributed by Columbia Management Investment Distributors, Inc., 290 Congress Street, Boston, MA 02210.

© 2022 Columbia Management Investment Advisers, LLC. All rights reserved.

PRO235_12_M01_(05/22)

COLUMBIA ACORN TRUST

Class A, Advisor Class, Class C, Institutional Class, Institutional 2 Class, Institutional 3 Class, and Class R Shares

STATEMENT OF ADDITIONAL INFORMATION

May 1, 2022

Equity Funds	Class A Shares	Class Adv Shares	Class C Shares	Class Inst Shares	Class Inst2 Shares	Class Inst3 Shares	Class R Shares
Columbia Acorn Fund	LACAX	CEARX	LIACX	ACRNX	CRBRX	CRBYX	—
Columbia Acorn International	LAIAX	CCIRX	LAICX	ACINX	CAIRX	CCYIX	CACRX
Columbia Acorn USA	LAUAX	CUSAX	LAUCX	AUSAX	CYSRX	CUSYX	—
Columbia Acorn International Select	LAFAX	CILRX	LFFCX	ACFFX	CRIRX	CSIRX	—
Columbia Acorn European Fund	CAEAX	CLOFX	CAECX	CAEZX	CAEEX	CAEYX	—
Fund of Funds
Columbia Thermostat Fund	CTFAX	CTORX	CTFDX	COTZX	CQTRX	CYYYX	—

This Statement of Additional Information (SAI) is not a prospectus, is not a substitute for reading any prospectus and is intended to be read in conjunction with the Funds’ prospectuses dated May 1, 2022. The most recent annual report for the Funds, which includes the Funds’ audited financial statements dated December 31, 2021, is incorporated by reference into this SAI.

Copies of the Funds’ current prospectuses and annual and semiannual reports may be obtained without charge by writing Columbia Management Investment Services Corp., P.O. Box 219104, Kansas City, MO 64121-9104, by calling Columbia Funds at 800.345.6611 or by visiting the Columbia Funds website at columbiathreadneedleus.com

SAI900_00_010_(05/22)

TABLE OF CONTENTS
SAI PRIMER	2
ABOUT THE TRUST	6
ABOUT THE FUNDS’ INVESTMENTS	7
Certain Investment Activity Limits	7
Fundamental and Non-Fundamental Investment Policies	7
Permissible Investments	14
Information Regarding Risks	60
Borrowings	103
Short Sales	104
Lending Securities	105
Portfolio Turnover	106
Disclosure of Portfolio Information	106
INVESTMENT ADVISORY AND OTHER SERVICES	112
The Investment Manager and Investment Advisory Services	112
The Administrator	122
The Principal Underwriter/Distributor	123
Other Roles and Relationships of Ameriprise Financial and its Affiliates — Certain Conflicts of Interest	125
Other Service Providers	131
Codes of Ethics	134
Proxy Voting Policies and Procedures	134
FUND GOVERNANCE	137
BROKERAGE ALLOCATION AND OTHER PRACTICES	150
Brokerage Commissions	154
Directed Brokerage	155
Securities of Regular Broker-Dealers	155
Additional Shareholder Servicing Payments	155
Additional Financial Intermediary Payments	157
Performance Disclosure	158
CAPITAL STOCK AND OTHER SECURITIES	160
Description of the Trust’s Shares	160
PURCHASE, REDEMPTION AND PRICING OF SHARES	164
Purchase and Redemption	164
Offering Price	165
Fair Valuation of Portfolio Securities	166
TAXATION	168
CONTROL PERSONS AND PRINCIPAL SHAREHOLDERS	186
APPENDIX A — DESCRIPTIONS OF SECURITIES RATINGS	A-1
APPENDIX B — THE INVESTMENT MANAGER’S PROXY VOTING PRINCIPLES AND PROCEDURES MANUAL	B-1
APPENDIX C — INFORMATION REGARDING PENDING AND SETTLED LEGAL PROCEEDINGS	C-1
APPENDIX S — MORE INFORMATION ABOUT CHOOSING A SHARE CLASS	S-1

1

SAI PRIMER

The SAI is a part of the Funds’ registration statement that is filed with the SEC. The registration statement includes the Funds’ prospectuses, the SAI and certain exhibits. The SAI, as supplemented from time to time, can be found online at columbiathreadneedleus.com, or by accessing the SEC’s website at sec.gov.

For purposes of any electronic version of this SAI, all references to websites, or universal resource locators (URLs), are intended to be inactive and are not meant to incorporate the contents of any website into this SAI, with the exception of the most recent annual report for the Funds, as noted on the front cover of this SAI.

The SAI generally provides additional information about the Funds that is not required to be in the Funds’ prospectuses. The SAI expands discussions of certain matters described in the Funds’ prospectuses and provides certain additional information about the Funds that may be of help or interest to some investors. Among other things, the SAI provides information about:

• the organization of the Trust;

• the Funds’ investments;

• the Funds’ investment adviser and other service providers, including roles and relationships of Ameriprise Financial and its affiliates, and conflicts of interest;

• the governance of the Funds;

• the Funds’ brokerage practices;

• the share classes offered by the Funds;

• the purchase, redemption and pricing of Fund shares; and

• the application of U.S. federal income tax laws.

If you have any questions about the Funds, please call Columbia Funds at 800.345.6611 or contact your financial advisor.

Before reading the SAI, you should consult the Glossary below, which defines certain of the terms used in the SAI.

Glossary

1933 Act	Securities Act of 1933, as amended
1934 Act	Securities Exchange Act of 1934, as amended
1940 Act	Investment Company Act of 1940, as amended
Administration Agreement	The administration agreement between the Trust, on behalf of the Funds, and the Administrator
Administrator	Columbia Wanger Asset Management, LLC
Advisory Agreement	The investment advisory agreement between the Trust, on behalf of the Funds, and the Investment Manager
Ameriprise Financial	Ameriprise Financial, Inc.
Bank of America	Bank of America Corporation
Board	The Trust’s Board of Trustees

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Business Day	A business day typically ends at the close of regular trading on the NYSE, usually at 4:00 p.m. Eastern time. If the NYSE is scheduled to close early, the business day will be considered to end as of the time of the NYSE’s scheduled close. The Fund will not treat an intraday unscheduled disruption in NYSE trading or an intraday unscheduled closing as a close of regular trading on the NYSE for these purposes and will price its shares as of the regularly scheduled closing time for that day (typically, 4:00 p.m. Eastern time). Notwithstanding the foregoing, the NAV of Fund shares may be determined at such other time or times (in addition to or in lieu of the time set forth above) as the Fund’s Board may approve or ratify. On holidays and other days when the NYSE is closed, the Fund’s NAV is not calculated and the Fund does not accept buy or sell orders. However, the value of the Fund’s assets may still be affected on such days to the extent that the Fund holds foreign securities that trade on days that foreign securities markets are open.
CFTC	The Commodity Futures Trading Commission, a U.S. government agency
Code	Internal Revenue Code of 1986, as amended
Codes of Ethics	The codes of ethics adopted by the Funds, the Investment Manager, Columbia Management and the Distributor pursuant to Rule 17j-1 under the 1940 Act
Columbia Acorn Funds, the Fund(s) or a Fund	One or more of the open-end management investment companies listed on the front cover of this SAI that are series of the Trust
Columbia Funds or Columbia Funds Complex	The fund complex, including the Columbia Wanger Funds and the Columbia Acorn Funds, that is comprised of the registered investment companies, including traditional mutual funds, closed-end funds and ETFs, advised by the Investment Manager or its affiliates (including Columbia Management)
Columbia Management	Columbia Management Investment Advisers, LLC, the Sub-Administrator
Columbia Threadneedle	The global brand name of the Columbia Management and Threadneedle group of companies
CWAM	Columbia Wanger Asset Management, LLC, the Investment Manager and the Administrator
Custodian	JPMorgan Chase Bank, N.A.
DBRS	DBRS Morningstar
Distribution Agreement	The distribution agreement between the Trust, on behalf of the Funds, and the Distributor
Distribution Plan	The plan adopted by the Board pursuant to Rule 12b-1 under the 1940 Act for the distribution of the Funds’ shares
Distributor	Columbia Management Investment Distributors, Inc.
DST	DST Asset Manager Solutions, Inc.

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FDIC	Federal Deposit Insurance Corporation
Financial Intermediary(ies)	One or more of the selling agents and/or servicing agents that are authorized to sell and/or service shares of the Funds, which may include broker-dealers and financial advisors, as well as firms that employ such broker-dealers and financial advisors, including, for example, brokerage firms, banks, investment advisers, third party administrators and other financial intermediaries
Fitch	Fitch Ratings, Inc.
The Fund(s) or a Fund	One or more of the open-end management investment companies listed on the front cover of this SAI that are series of the Trust
Fund(s) of Funds	One or more of the “funds of funds” in the Columbia Funds Complex, including Columbia Thermostat Fund, that invests its assets in a mix of underlying funds, or Portfolio Funds
GSAL	Goldman Sachs Agency Lending, the Funds’ securities lending agent
Independent Trustee(s)	The Trustee(s) of the Board who are not “interested persons” of the Funds as defined in the 1940 Act
International/Global Equity Fund(s)	One or more of the international/global equity funds in the Columbia Funds Complex
Investment Manager	Columbia Wanger Asset Management, LLC
IRS	United States Internal Revenue Service
JPMorgan	JPMorgan Chase Bank, N.A., the Custodian
KBRA	Kroll Bond Rating Agency
LIBOR	London Interbank Offered Rate*
Moody’s	Moody’s Investors Service, Inc.
MSCI	Morgan Stanley Capital International
NASDAQ	National Association of Securities Dealers Automated Quotations system
NAV	Net asset value per share of a Fund
NRSRO	Nationally recognized statistical ratings organization (such as Moody’s, Fitch or S&P)
NYSE	New York Stock Exchange
Portfolio Fund(s)	One or more of the underlying mutual funds in which a Fund of Funds, including Columbia Thermostat Fund, invests all or a portion of its assets
Principal Underwriter	Columbia Management Investment Distributors, Inc.
RIC	A “regulated investment company,” as such term is used in the Code

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S&P	S&P Global Ratings, a division of S&P Global Inc. (“Standard & Poor’s” and “S&P” are trademarks of S&P Global Inc. and have been licensed for use by the Investment Manager; the Columbia Funds are not sponsored, endorsed, sold or promoted by Standard & Poor’s and Standard & Poor’s makes no representation regarding the advisability of investing in the Columbia Funds)
SAI	This Statement of Additional Information
SEC	United States Securities and Exchange Commission
SOFR	Secured Overnight Financing Rate
Sub-Administrator	Columbia Management
Threadneedle	Threadneedle International Limited
Transfer Agency Agreement	The transfer agency agreement between the Trust, on behalf of the Funds, and Columbia Management Investment Services Corp.
Transfer Agent	Columbia Management Investment Services Corp.
The Trust	Columbia Acorn Trust, the open-end registered investment company to which this SAI relates
Trustee(s)	One or more of the Board’s Trustees

* Please see “LIBOR Replacement Risk” in the “Information Regarding Risks” section for more information about the phaseout of LIBOR and related reference rates.

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ABOUT THE TRUST

The Trust is an open-end investment company registered under the 1940 Act within the Columbia Funds Complex.

The Trust was organized as a Massachusetts business trust on April 21, 1992 as successor to The Acorn Fund, Inc., which became the Columbia Acorn series of the Trust. Prior to October 13, 2003, the Trust was named Liberty Acorn Trust, and prior to September 29, 2000, it was named Acorn Investment Trust.

Each of the Funds is a series of the Trust. Each Fund operates as an open-end diversified management investment company and has a fiscal year end of December 31^st.

The Funds offer the following classes of shares that have different fees and expenses and other features:

	Class A	Class Adv	Class C	Class Inst(1)	Class Inst2(2)	Class Inst3(3)	Class R
Columbia Acorn Fund	✓	✓	✓	✓	✓	✓	—
Columbia Acorn International	✓	✓	✓	✓	✓	✓	✓
Columbia Acorn USA	✓	✓	✓	✓	✓	✓	—
Columbia Acorn International Select	✓	✓	✓	✓	✓	✓	—
Columbia Acorn European Fund	✓	✓	✓	✓	✓	✓	—
Columbia Thermostat Fund	✓	✓	✓	✓	✓	✓	—

⁽¹⁾ Financial Intermediaries that clear Fund share transactions through designated Financial Intermediaries and their mutual fund trading platforms that were given specific written notice from the Transfer Agent of the termination, effective March 31, 2013, of their eligibility for new purchases of Class Inst shares and omnibus retirement plans are no longer permitted to establish new Class Inst accounts, subject to certain exceptions. Omnibus retirement plans that opened and, subject to exceptions, funded a Class Inst account as of close of business on March 28, 2013, and have continuously held Class Inst shares in such account after such date, may generally continue to make additional purchases of Class Inst shares, open new Class Inst accounts and add new participants. In certain circumstances and in the sole discretion of the Distributor, omnibus retirement plans affiliated with a grandfathered plan may also open new Class Inst accounts. Accounts of Financial Intermediaries (other than omnibus retirement plans) that clear Fund share transactions for their client or customer accounts through designated Financial Intermediaries and their mutual fund trading platforms are not permitted to establish new Class Inst accounts or make additional purchases of Class Inst shares (other than through reinvestment of distributions).

⁽²⁾  Shareholders with Class Inst2 shares accounts funded before November 8, 2012 who do not satisfy the current eligibility criteria for Class Inst2 shares may not establish new Class Inst2 accounts but may continue to make additional purchases of Class Inst2 shares in existing accounts. In addition, investment advisory programs and similar programs that opened a Class Inst2 account as of May 1, 2010, and continuously hold Class Inst2 shares in such account after such date, may generally not only continue to make additional purchases of Class Inst2 shares but also open new Class Inst2 accounts and add new shareholders in the program.

⁽³⁾  Shareholders with Class Inst3 shares accounts funded before November 8, 2012 who do not satisfy the current eligibility criteria for Class Inst3 shares may not establish new accounts but may continue to make additional purchases of Class Inst3 shares in existing accounts.

On September 29, 2000, the Funds (other than Columbia Acorn European Fund and Columbia Thermostat Fund) changed their names, respectively, to Liberty Acorn Fund, Liberty Acorn International, Liberty Acorn USA, Liberty Acorn Foreign Forty and Liberty Acorn Twenty. Effective October 13, 2003, the Funds (other than Columbia Acorn European Fund and Columbia Thermostat Fund) and the Trust changed their names to their current names.

The Trust is not required to hold annual meetings of shareholders, but special meetings may be called for certain purposes. The last meeting to elect trustees was held on February 27, 2015. Shareholders receive one vote for each Fund share held. Shares of each Fund and any other series of the Trust that may be in existence from time to time generally vote together, except when required by law to vote separately by Fund or by class. Shareholders owning in the aggregate 10 percent or more of Trust shares may call meetings to consider removal of Trustees of the Trust. Under certain circumstances, the Trust will provide information to assist shareholders in calling such a meeting.

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ABOUT THE FUNDS’ INVESTMENTS

The investment objective, principal investment strategies (i.e., as used in this SAI and the corresponding prospectuses, a strategy which generally involves the ability to invest 10% or more of a Fund’s total assets) and related principal investment risks for each Fund are discussed in each Fund’s prospectus.

Certain Investment Activity Limits

The overall investment and other activities of the Investment Manager and its affiliates may limit the investment opportunities for each Fund in certain markets, industries or transactions or in individual issuers where limitations are imposed by regulators upon the aggregate amount of investment by the Funds and other accounts managed by the Investment Manager and accounts of its affiliates. From time to time, each Fund’s activities also may be restricted because of regulatory restrictions applicable to the Investment Manager and its affiliates and/or because of their internal policies. See Investment Advisory and Other Services — Other Roles and Relationships of Ameriprise Financial and its Affiliates — Certain Conflicts of Interest.

Fundamental and Non-Fundamental Investment Policies

The following discussion of “fundamental” and “non-fundamental” investment policies and limitations for each Fund supplements the discussion of investment policies in the Fund’s prospectus. A fundamental policy may be changed only with Board and shareholder approval. A non-fundamental policy may be changed by the Board and does not require shareholder approval, but may require notice to shareholders in certain instances.

Unless otherwise noted in a Fund’s prospectus or this SAI, whenever an investment policy or limitation states a maximum percentage of a Fund’s assets that may be invested in any security or other asset, or sets forth a policy regarding an investment standard, compliance with such percentage limitation or standard will be determined solely at the time of the Fund’s acquisition of such security or asset. Thus, a Fund generally may continue to hold a security, even though it causes the Fund to exceed a percentage limitation or not meet a standard, because of post-acquisition changes, including fluctuation in the value of the Fund’s assets. Borrowings and other instruments that may give rise to leverage and the restriction on investing in illiquid investments are monitored on an ongoing basis.

Fundamental Investment Policies

The 1940 Act provides that a “vote of a majority of the outstanding voting securities” means the affirmative vote of the lesser of (1) more than 50% of the outstanding shares of a Fund, or (2) 67% or more of the shares present at a meeting if more than 50% of the outstanding shares are represented at the meeting in person or by proxy. The following fundamental investment policies cannot be changed without such a vote.

For purposes of applying the limitations included in the issuer diversification policies set forth below, the Funds do not consider futures or swaps central counterparties, where the Funds have exposure to such central counterparties in the course of making investments in futures and securities, to be issuers.

With respect to the policies regarding senior securities set forth below, a “senior security” is an obligation with respect to the earnings or assets of a company that takes precedence over the claims of that company’s common stock with respect to the same earnings or assets. The 1940 Act prohibits open-end mutual funds from issuing senior securities other than certain borrowings from a bank, but SEC staff interpretations allow a Fund to engage in certain types of transactions that otherwise might raise senior security concerns (such as short sales, buying and selling financial futures contracts and other derivative instruments and selling put and call options), provided that the Fund segregates or designates on the Fund’s books and records liquid assets, or, as permitted in accordance with SEC staff interpretations, otherwise covers the transaction with offsetting portfolio securities, in amounts sufficient to offset any liability associated with the transaction. The exception in the fundamental policy allows the Fund to operate in reliance upon these staff interpretations.

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Columbia Acorn Fund may not, as a matter of fundamental policy:

1. Invest more than 5% of its assets (valued at time of investment) in securities of any one issuer, except in government obligations.

2. Acquire securities of any one issuer which at the time of investment (a) represent more than 10% of the voting securities of the issuer or (b) have a value greater than 10% of the value of the outstanding securities of the issuer.

3. Invest more than 25% of its assets (valued at time of investment) in securities of companies in any one industry.

4. Invest more than 5% of its assets (valued at time of investment) in securities of issuers with less than three years’ operation (including predecessors).

5. Borrow money except (a) from banks for temporary or emergency purposes in amounts not exceeding 33% of the value of the Fund’s assets at the time of borrowing, and (b) in connection with transactions in options and in securities index futures. The Fund will not purchase additional securities when its borrowings, less amounts receivable on sales of portfolio securities, exceed 5% of total assets.

6. Pledge, mortgage or hypothecate its assets, except in connection with permitted borrowings.

7. Underwrite the distribution of securities of other issuers; however, the Fund may acquire “restricted” securities which, in the event of a resale, might be required to be registered under the Securities Act of 1933 on the ground that the Fund could be regarded as an underwriter as defined by that act with respect to such resale; but the Fund will limit its total investment in restricted securities and in other securities for which there is no ready market to not more than 10% of its total assets at the time of acquisition.

8. Purchase and sell real estate or interests in real estate, although it may invest in marketable securities of enterprises which invest in real estate or interests in real estate.

9. Purchase and sell commodities or commodity contracts, except that it may enter into (a) futures and options on futures and (b) forward contracts.

10. Make margin purchases of securities, except for use of such short-term credits as are needed for clearance of transactions and except in connection with transactions in options, futures and options on futures.

11. Sell securities short or maintain a short position, except short sales “against the box.”

12. Participate in a joint or on a joint or several basis in any trading account in securities.

13. Invest in companies for the purpose of management or the exercise of control.

14. Issue any senior security except to the extent permitted under the Investment Company Act of 1940.

15. Make loans, but this restriction shall not prevent the Fund from (a) buying a part of an issue of bonds, debentures, or other obligations that are publicly distributed, or from investing up to an aggregate of 15% of its total assets (taken at market value at the time of each purchase) in parts of issues of bonds, debentures or other obligations of a type privately placed with financial institutions, (b) investing in repurchase agreements, or (c) lending portfolio securities, provided that it may not lend securities if, as a result, the aggregate value of all securities loaned would exceed 33% of its total assets (taken at market value at the time of such loan).

Columbia Acorn International may not, as a matter of fundamental policy:

1. With respect to 75% of the value of the Fund’s total assets, invest more than 5% of its total assets (valued at time of investment) in securities of a single issuer, except securities issued or guaranteed by the government of the U.S., or any of its agencies or instrumentalities.

2. Acquire securities of any one issuer that at the time of investment (a) represent more than 10% of the voting securities of the issuer or (b) have a value greater than 10% of the value of the outstanding securities of the issuer.

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3. Invest more than 25% of its assets (valued at time of investment) in securities of companies in any one industry.

4. Make loans, but this restriction shall not prevent the Fund from (a) buying a part of an issue of bonds, debentures, or other obligations that are publicly distributed, or from investing up to an aggregate of 15% of its total assets (taken at market value at the time of each purchase) in parts of issues of bonds, debentures or other obligations of a type privately placed with financial institutions, (b) investing in repurchase agreements, or (c) lending portfolio securities, provided that it may not lend securities if, as a result, the aggregate value of all securities loaned would exceed 33% of its total assets (taken at market value at the time of such loan).

5. Borrow money except (a) from banks for temporary or emergency purposes in amounts not exceeding 33% of the value of the Fund’s total assets at the time of borrowing, and (b) in connection with transactions in options, futures and options on futures. The Fund will not purchase additional securities when its borrowings, less amounts receivable on sales of portfolio securities, exceed 5% of total assets.

6. Underwrite the distribution of securities of other issuers; however the Fund may acquire “restricted” securities which, in the event of a resale, might be required to be registered under the Securities Act of 1933 on the ground that the Fund could be regarded as an underwriter as defined by that act with respect to such resale; but the Fund will limit its total investment in restricted securities and in other securities for which there is no ready market, including repurchase agreements maturing in more than seven days, to not more than 15% of its total assets at the time of acquisition.

7. Purchase and sell real estate or interests in real estate, although it may invest in marketable securities of enterprises that invest in real estate or interests in real estate.

8. Purchase and sell commodities or commodity contracts, except that it may enter into (a) futures and options on futures and (b) forward contracts.

9. Make margin purchases of securities, except for use of such short-term credits as are needed for clearance of transactions and except in connection with transactions in options, futures and options on futures.

10. Sell securities short or maintain a short position, except short sales “against the box.”

11. Issue any senior security except to the extent permitted under the Investment Company Act of 1940.

Columbia Acorn USA may not, as a matter of fundamental policy:

1. With respect to 75% of the value of the Fund’s total assets, invest more than 5% of its total assets (valued at time of investment) in securities of a single issuer, except securities issued or guaranteed by the government of the U.S., or any of its agencies or instrumentalities.

2. Acquire securities of any one issuer which at the time of investment (a) represent more than 10% of the voting securities of the issuer or (b) have a value greater than 10% of the value of the outstanding securities of the issuer.

3. Invest more than 25% of its assets (valued at time of investment) in securities of companies in any one industry, except that this restriction does not apply to investments in U.S. government securities.

4. Make loans, but this restriction shall not prevent the Fund from (a) buying a part of an issue of bonds, debentures, or other obligations that are publicly distributed, or from investing up to an aggregate of 15% of its total assets (taken at market value at the time of each purchase) in parts of issues of bonds, debentures or other obligations of a type privately placed with financial institutions, (b) investing in repurchase agreements, or (c) lending portfolio securities, provided that it may not lend securities if, as a result, the aggregate value of all securities loaned would exceed 33% of its total assets (taken at market value at the time of such loan).

5. Borrow money except (a) from banks for temporary or emergency purposes in amounts not exceeding 33% of the value of the Fund’s total assets at the time of borrowing, and (b) in connection with transactions in options, futures and options on futures.

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6. Underwrite the distribution of securities of other issuers; however, the Fund may acquire “restricted” securities which, in the event of a resale, might be required to be registered under the Securities Act of 1933 on the ground that the Fund could be regarded as an underwriter as defined by that act with respect to such resale.

7. Purchase and sell real estate or interests in real estate, although it may invest in marketable securities of enterprises which invest in real estate or interests in real estate.

8. Purchase and sell commodities or commodity contracts, except that it may enter into (a) futures and options on futures and (b) foreign currency contracts.

9. Make margin purchases of securities, except for use of such short-term credits as are needed for clearance of transactions and except in connection with transactions in options, futures and options on futures.

10. Issue any senior security except to the extent permitted under the Investment Company Act of 1940.

Columbia Acorn International Select may not, as a matter of fundamental policy:

1. With respect to 75% of the value of the Fund’s total assets, invest more than 5% of its total assets (valued at the time of investment) in securities of a single issuer, except securities issued or guaranteed by the government of the U.S., or any of its agencies or instrumentalities.

2. Acquire securities of any one issuer which at the time of investment (a) represent more than 10% of the voting securities of the issuer or (b) have a value greater than 10% of the value of the outstanding securities of the issuer.

3. Invest more than 25% of its total assets in a single issuer (other than U.S. government securities);

4. Invest more than 25% of its total assets in the securities of companies in a single industry (excluding U.S. government securities).

5. Make loans, but this restriction shall not prevent the Fund from (a) investing in debt securities, (b) investing in repurchase agreements, or (c) lending its portfolio securities, provided that it may not lend securities if, as a result, the aggregate value of all securities loaned would exceed 33% of its total assets (taken at market value at the time of such loan).

6. Borrow money except (a) from banks for temporary or emergency purposes in amounts not exceeding 33% of the value of the Fund’s total assets at the time of borrowing, and (b) in connection with transactions in options, futures and options on futures.

7. Underwrite the distribution of securities of other issuers; however, the Fund may acquire “restricted” securities which, in the event of a resale, might be required to be registered under the Securities Act of 1933 on the ground that the Fund could be regarded as an underwriter as defined by that act with respect to such resale.

8. Purchase and sell real estate or interests in real estate, although it may invest in marketable securities of enterprises which invest in real estate or interests in real estate.

9. Purchase and sell commodities or commodity contracts, except that it may enter into (a) futures and options on futures and (b) foreign currency contracts.

10. Make margin purchases of securities, except for use of such short-term credits as are needed for clearance of transactions and except in connection with transactions in options, futures and options on futures.

11. Issue any senior security except to the extent permitted under the Investment Company Act of 1940.

Columbia Acorn European Fund may not, as a matter of fundamental policy:

1. With respect to 75% of the value of the Fund’s total assets, invest more than 5% of its total assets (valued at time of investment) in securities of a single issuer, except securities issued or guaranteed by the government of the U.S. or any of its agencies or instrumentalities.

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2. Acquire securities of any one issuer that at the time of investment (a) represent more than 10% of the voting securities of the issuer or (b) have a value greater than 10% of the value of the outstanding securities of the issuer.

3. Invest more than 25% of its total assets (valued at time of investment) in securities of companies in any one industry.

4. Make loans, but this restriction shall not prevent the Fund from (a) buying a part of an issue of bonds, debentures, or other obligations that are publicly distributed, or from investing up to an aggregate of 15% of its total assets (valued at the time of investment) in parts of issues of bonds, debentures or other obligations of a type privately placed with financial institutions, (b) investing in repurchase agreements, or (c) lending its portfolio securities, provided that it may not lend securities if, as a result, the aggregate value of all securities loaned would exceed 33% of its total assets (valued at the time of such loan).

5. Borrow money except (a) from banks for temporary or emergency purposes in amounts not exceeding 33% of the value of the Fund’s total assets (valued at the time of such borrowing) and (b) in connection with transactions in options, futures and options on futures. The Fund will not purchase additional securities when its borrowings, less amounts receivable on sales of portfolio securities, exceed 5% of its total assets.

6. Underwrite the distribution of securities of other issuers; however the Fund may acquire “restricted” securities which, in the event of a resale, might be required to be registered under the 1933 Act on the ground that the Fund could be regarded as an underwriter as defined by the 1933 Act with respect to such resale.

7. Purchase and sell real estate or interests in real estate, although it may invest in marketable securities of enterprises that invest in real estate or interests in real estate.

8. Purchase and sell commodities or commodity contracts, except that it may enter into (a) futures and options on futures and (b) forward contracts.

9. Make margin purchases of securities, except for use of such short-term credits as are needed for clearance of transactions and except in connection with transactions in options, futures and options on futures.

10. Issue any senior security except to the extent permitted under the 1940 Act.

Columbia Thermostat Fund will, as a matter of fundamental policy, concentrate its investments in shares of other mutual funds.

Columbia Thermostat Fund may not, as a matter of fundamental policy:

1. With respect to 75% of the value of the Fund’s total assets, invest more than 5% of its total assets (valued at time of investment) in securities of a single issuer, except shares of Portfolio Funds and securities issued or guaranteed by the government of the U.S., or any of its agencies or instrumentalities.

2. Make loans, but this restriction shall not prevent the Fund from (a) buying a part of an issue of bonds, debentures, or other obligations that are publicly distributed, or from investing up to an aggregate of 15% of its total assets (taken at market value at the time of each purchase) in parts of issues of bonds, debentures or other obligations of a type privately placed with financial institutions, (b) investing in repurchase agreements, or (c) lending portfolio securities, provided that it may not lend securities if, as a result, the aggregate value of all securities loaned would exceed 33% of its total assets (taken at market value at the time of such loan).

3. Borrow money except (a) from banks for temporary or emergency purposes in amounts not exceeding 33% of the value of the Fund’s total assets at the time of borrowing, and (b) in connection with transactions in options, futures and options on futures.

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4. Underwrite the distribution of securities of other issuers; however, the Fund may acquire “restricted” securities which, in the event of a resale, might be required to be registered under the Securities Act of 1933 on the ground that the Fund could be regarded as an underwriter as defined by that act with respect to such resale.

5. Purchase and sell real estate or interests in real estate, although it may invest in marketable securities of enterprises which invest in real estate or interests in real estate.

6. Purchase and sell commodities or commodity contracts, except that it may enter into (a) futures and options on futures and (b) forward contracts.

7. Make margin purchases of securities, except for use of such short-term credits as are needed for clearance of transactions and except in connection with transactions in options, futures and options on futures.

8. Sell securities short or maintain a short position, except short sales “against the box.”

9. Invest in companies for the purpose of management or the exercise of control.

10. Issue any senior security except to the extent permitted under the 1940 Act.

11. Invest 25% or more of its total assets in the securities of a single industry (excluding U.S. Government securities and securities of other investment companies).

Non-Fundamental Investment Policies

Each Fund, as a matter of non-fundamental policy, may not:

1. Acquire securities of other registered investment companies except in compliance with the 1940 Act.

2. Invest in companies for the purpose of management or the exercise of control.

3. Acquire any illiquid investment (defined as any investment that the Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without the sale or disposition significantly changing the market value of the investment) if, immediately after the acquisition, the Fund would have invested more than 15% of its net assets in illiquid investments that are assets. If a Fund holds more than 15% of its net assets in illiquid investments that are assets:

(a) It must cause the administrator of the Fund’s liquidity risk management program to report such an occurrence to the Board within one business day of the occurrence, with an explanation of the extent and causes of the occurrence, and how the Fund plans to bring its illiquid investments that are assets to or below 15% of its net assets within a reasonable period of time; and

(b) If the amount of the Fund’s illiquid investments that are assets is still above 15% of its net assets 30 days from the occurrence (and at each consecutive 30 day period thereafter), the Board, including a majority of Independent Trustees, must assess whether the plan presented to it continues to be in the best interest of the Fund.

4. Make short sales of securities unless the Fund owns at least an equal amount of such securities, or owns securities that are convertible or exchangeable, without payment of further consideration, into at least an equal amount of such securities.

Each Fund, except Columbia Acorn Fund, as a matter of non-fundamental policy, may not: pledge, mortgage or hypothecate its assets, except as may be necessary in connection with permitted borrowings or in connection with short sales, options, futures and options on futures.

Each Fund other than Columbia Thermostat Fund, as a matter of non-fundamental policy, may not: if its shares are purchased by another investment company in reliance on Section 12(d)(1)(G) of the 1940 Act, purchase securities of another registered open-end investment company or registered unit investment trust in reliance on Section 12(d)(1)(F) or (G) of the 1940 Act, for so long as the Fund’s shares are held by such other investment company.

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Each of Columbia Acorn Fund, Columbia Acorn International, Columbia Acorn USA and Columbia Thermostat Fund, as a matter of non-fundamental policy, may not: invest more than 10% of its total assets (valued at the time of investment) in restricted securities subject to the Funds’ non-fundamental policy described above that prohibits the Fund from investing more than 15% of its net assets in illiquid investments.

Columbia Acorn Fund, as a matter of non-fundamental policy, may not: invest more than 33% of its total assets (valued at time of investment) in securities of foreign issuers.

Each of Columbia Acorn International and Columbia Acorn International Select, as a matter of non-fundamental policy, may not: invest more than 25% of its total assets in domestic securities, under normal market conditions.

Columbia Acorn USA, as a matter of non-fundamental policy, may not:

1. Under normal circumstances, invest less than 80% of its net assets (plus any borrowings for investment purposes) in domestic securities. The Fund will notify shareholders at least 60 days prior to any

change in this policy.

2. Invest more than 20% of its total assets (valued at the time of investment) in the securities of foreign issuers.

Columbia Acorn International Select, as a matter of non-fundamental policy, may not: under normal circumstances, invest less than 65% of its net assets in the securities of foreign companies based in developed markets outside the United States.

Columbia Acorn European Fund, as a matter of non-fundamental policy, may not:

1. Under normal circumstances, invest less than 80% of its net assets (plus any borrowings for investment purposes) in European companies. For purposes of these non-fundamental policies, the Fund may invest in a company if (i) it is domiciled in, or the principal trading market for its securities is in, a European country, (ii) it derives 50% or more of its economic value from goods produced, sales made or services performed in a European country or has at least 50% of its assets in a European country or (iii) it is a holding company that predominately holds shares in such companies. The Fund will notify shareholders at least 60 days prior to any change in this policy.

2. Under normal circumstances, invest less than 70% of its total assets in companies in Western European countries (for example, the United Kingdom, Germany, France and Italy), or more than 30% of its total assets in companies in emerging Central and Eastern European countries (for example, Poland, the Czech Republic, Turkey and Cyprus), including up to 10% of its total assets in companies in Russia and the Ukraine.

Investment Restrictions of the Portfolio Funds

For the Portfolio Funds’ investment policies, refer to their respective statements of additional information, which are available on the Columbia Funds website at columbiathreadneedle.com/us and on the SEC’s website at sec.gov.

Under certain circumstances, a Portfolio Fund may determine to make payment of a redemption request by Columbia Thermostat Fund wholly or partly by a distribution in-kind of securities from its portfolio, instead of cash, in accordance with the rules of the SEC. In such cases, the Fund may hold securities distributed by a Portfolio Fund until the Investment Manager determines that it is appropriate to dispose of such securities.

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Permissible Investments

Each Fund’s prospectus identifies and summarizes the individual types of securities in which the Fund invests as part of its principal investment strategies and the principal risks associated with such investments. In this section the term “Fund” refers to a Fund or a Portfolio Fund, except where otherwise indicated. To the extent that a type of security identified in the table below for a Fund is not described in the Fund’s prospectus (or as a sub-category of such security type in this SAI), the Fund may invest in such security type as part of its non-principal investment strategies. Unless otherwise indicated in the prospectus or this SAI, the investment objective and policies of a Fund may be changed without shareholder approval.

The 1940 Act normally prohibits mutual funds from investing in other mutual funds beyond certain limits. Columbia Thermostat Fund is a Fund of Funds that relies on Section 12(d)(1)(G) of the 1940 Act to exceed those limits subject to certain conditions, including primarily that the Fund only invest in affiliated underlying funds. Accordingly, Columbia Thermostat Fund may: (i) own more than 3% of the total outstanding stock of a Portfolio Fund; (ii) invest more than 5% of its total assets in any one such Portfolio Fund; and (iii) invest more than 10% of its total assets, collectively, in Portfolio Fund shares. See About the Funds’ Investments — Permissible Fund Investments — Investments in Other Investment Companies for information.

As of the date of this SAI, and as discussed in the Fund’s prospectus, Columbia Thermostat Fund invests in the following Portfolio Funds: Columbia Acorn Fund, Columbia Contrarian Core Fund, Columbia Emerging Markets Fund, Columbia Large Cap Enhanced Core Fund, Columbia Large Cap Index Fund, Columbia Research Enhanced Core ETF, Columbia Select Mid Cap Value Fund, Columbia Corporate Income Fund, Columbia Diversified Fixed Income Allocation ETF, Columbia Quality Income Fund, Columbia Short Term Bond Fund, Columbia Total Return Bond Fund and Columbia U.S. Treasury Index Fund.

The table below identifies for each Fund, or in the case of Columbia Thermostat Fund, for each Portfolio Fund, certain types of securities in which it is permitted to invest, including those described in each Fund’s prospectus. A Fund generally has the ability to invest 10% or more of its total assets in each type of security described in its prospectus (and in each sub-category of such security type described in this SAI). To the extent that a type of security identified below for a Fund is not described in the Fund’s prospectus (or as a sub-category of such security type in this SAI), the Fund generally invests less than 10% of its total assets in such security type, except as noted below and except that each Fund may invest in derivatives as described in its prospectus.

Information about individual types of securities (including certain of their associated risks) in which some or all of the Funds or Portfolio Funds may invest is set forth below. Each Fund’s investment in these types of securities is subject to its investment objective and fundamental and non-fundamental investment policies. The information in the table below does not describe every type of investment, technique or risk to which a Fund may be exposed.

Temporary Defensive Positions. Each Fund may from time to time take temporary defensive investment positions that are inconsistent with the Fund’s principal investment strategies in attempting to respond to adverse market, economic, political, social or other conditions. These investment positions may include, without limitation, investing some or all of its assets in money market instruments or shares of affiliated or unaffiliated government money market funds or holding some or all of its assets in cash or cash equivalents. Each Fund may take such defensive positions for as long a period as the Investment Manager deems necessary. During these times, the Investment Manager may make frequent portfolio changes, which could result in increased trading expenses and taxes, and decreased Fund performance.

See also About the Funds’ Investments — Permissible Investments and Related Risks — Money Market Instruments.

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Permissible Fund Investments

Investment Type	Columbia Acorn Fund	Columbia Acorn USA	Columbia Acorn International	Columbia Acorn International Select		Columbia Acorn European Fund	Columbia Thermostat Fund
Asset-Backed Securities	✓	✓	✓	✓		✓	✓
Bank Obligations (Domestic and Foreign)	✓	✓	✓	✓		✓	✓
Collateralized Bond Obligations							✓
Commercial Paper							✓
Common Stock	✓	✓	✓	✓		✓	✓
Convertible Securities	✓	✓	✓	✓		✓	✓
Corporate Debt Securities	✓	✓	✓	✓		✓	✓
Custody Receipts and Trust Certificates	✓	✓	✓	✓		✓	✓
Debt Obligations							✓
Depositary Receipts	✓	✓	✓	✓		✓	✓
Derivatives
Index or Linked Securities (Structured Products)	✓	✓	✓	✓		✓	✓
Futures Contracts and Options on Futures Contracts	✓	✓	✓	✓		✓	✓
Options on Stocks, Stock Indices and Other Indices	✓	✓	✓	✓		✓	✓
Swap Agreements	✓	✓	✓	✓		✓	✓
Dollar Rolls							✓
Exchange-Traded Notes							✓
Foreign Currency Transactions	✓	✓	✓	✓		✓	✓
Foreign Securities (including Depository Receipts)	✓	✓	✓	✓		✓	✓
Guaranteed Investment Contracts							✓
High Yield Securities	✓	✓	✓	✓		✓	✓
Illiquid Investments	✓	✓	✓	✓		✓	✓
Inflation Protected Securities							✓
Initial Public Offerings	✓	✓	✓	✓		✓	✓
Inverse Floaters							✓
Investments in other Investment Companies (including ETFs)	✓	✓	✓	✓		✓	✓
Listed Private Equity Funds							✓
Money Market Instruments	✓	✓	✓	✓		✓	✓
Mortgage-Backed Securities							✓
Municipal Securities							✓
Participation Interests	✓	✓	✓	✓		✓	✓
Partnership Securities	✓	✓	✓	✓	*	✓	✓
Preferred Stock	✓	✓	✓	✓		✓	✓
Private Placement and Other Restricted Securities	✓	✓	✓	✓		✓	✓
Real Estate Investment Trusts	✓	✓	✓	✓	*	✓	✓
Repurchase Agreements	✓	✓	✓	✓		✓	✓
Reverse Repurchase Agreements	✓	✓	✓	✓		✓	✓
Short Sales***							✓
Sovereign Debt							✓
Standby Commitments							✓
Stripped Securities	✓	✓	✓	✓		✓	✓

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Investment Type	Columbia Acorn Fund	Columbia Acorn USA	Columbia Acorn International	Columbia Acorn International Select	Columbia Acorn European Fund	Columbia Thermostat Fund
U.S. Government and Related Obligations	✓	✓	✓	✓	✓	✓
Variable- and Floating-Rate Obligations						✓
Warrants and Rights	✓	✓	✓	✓	✓	✓
When-Issued, Delayed Delivery and Forward Commitment Transactions	✓	✓	✓	✓	✓	✓
Zero-Coupon, Pay-in-Kind and Step-Coupon Securities	✓	✓	✓	✓	✓	✓

* Columbia Acorn International Select may generally invest up to 20% of its total assets in real estate investment trusts (REITs) and master limited partnerships (MLPs).

*** Certain Portfolio Funds in which Columbia Thermostat Fund invests may participate in short sales that are not “against the box.” Like the other Acorn Funds, Columbia Thermostat Fund’s direct participation in short sales is limited to short sales “against the box.” See About the Funds’ Investments — Short Sales and About the Funds’ Investments — Fundamental and Non-Fundamental Investment Policies.

Asset-Backed Securities

Asset-backed securities represent interests in, or debt instruments that are backed by, pools of various types of assets that generate cash payments generally over fixed periods of time, such as, among others, motor vehicle installment sales, contracts, installment loan contracts, leases of various types of real and personal property, and receivables from revolving (credit card) agreements. Such securities entitle the security holders to receive distributions (i.e., principal and interest) that are tied to the payments made by the borrower on the underlying assets (less fees paid to the originator, servicer, or other parties, and fees paid for credit enhancement), so that the payments made on the underlying assets effectively pass through to such security holders. Asset-backed securities typically are created by an originator of loans or owner of accounts receivable that sells such underlying assets to a special purpose entity in a process called a securitization. The special purpose entity issues securities that are backed by the payments on the underlying assets, and have a minimum denomination and specific term. Asset-backed securities may be structured as fixed-, variable- or floating-rate obligations or as zero-coupon, pay-in-kind and step-coupon securities and may be privately placed or publicly offered. Collateralized loan obligations and collateralized debt obligations are examples of asset-backed securities. See Permissible Fund Investments — Variable- and Floating-Rate Obligations, — Debt Obligations — Zero Coupon, Pay-in-Kind and Step-Coupon Securities and — Private Placement and Other Restricted Securities for more information.

Although one or more of the other risks described in this SAI may also apply, the risks typically associated with asset-backed securities include: Credit Risk, Interest Rate Risk, Liquidity Risk and Prepayment and Extension Risk. See Information Regarding Risks.

Bank Obligations (Domestic and Foreign)

Bank obligations include certificates of deposit, bankers’ acceptances, time deposits and promissory notes that earn a specified rate of return and may be issued by (i) a domestic branch of a domestic bank, (ii) a foreign branch of a domestic bank, (iii) a domestic branch of a foreign bank or (iv) a foreign branch of a foreign bank. Bank obligations may be structured as fixed-, variable- or floating-rate obligations. See Permissible Fund Investments — Variable- and Floating-Rate Obligations for more information.

Certificates of deposit, or so-called CDs, typically are interest-bearing debt instruments issued by banks and have maturities ranging from a few weeks to several years. Yankee dollar certificates of deposit are negotiable CDs issued in the United States by branches and agencies of foreign banks. Eurodollar certificates of deposit are CDs issued by foreign banks with interest and principal paid in U.S. dollars. Eurodollar and Yankee Dollar CDs typically have maturities of less than two years and have interest rates that typically are pegged to a reference rate such as LIBOR or SOFR. Bankers’ acceptances are time drafts drawn on and accepted by banks, are a

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customary means of effecting payment for merchandise sold in import-export transactions and are a general source of financing. A time deposit can be either a savings account or CD that is an obligation of a financial institution for a fixed term. Typically, there are penalties for early withdrawals of time deposits. Promissory notes are written commitments of the maker to pay the payee a specified sum of money either on demand or at a fixed or determinable future date, with or without interest.

Bank investment contracts are issued by banks. Pursuant to such contracts, a Fund may make cash contributions to a deposit fund of a bank. The bank then credits to the Fund payments at floating or fixed interest rates. A Fund also may hold funds on deposit with its custodian for temporary purposes.

Certain bank obligations, such as some CDs, are insured by the FDIC up to certain specified limits. Many other bank obligations, however, are neither guaranteed nor insured by the FDIC or the U.S. Government. These bank obligations are “backed” only by the creditworthiness of the issuing bank or parent financial institution. Domestic and foreign banks are subject to different governmental regulation. Accordingly, certain obligations of foreign banks, including Eurodollar and Yankee dollar obligations, involve different and/or heightened investment risks than those affecting obligations of domestic banks, including, among others, the possibilities that: (i) their liquidity could be impaired because of political or economic developments; (ii) the obligations may be less marketable than comparable obligations of domestic banks; (iii) a foreign jurisdiction might impose withholding and other taxes at high levels on interest income; (iv) foreign deposits may be seized or nationalized; (v) foreign governmental restrictions such as exchange controls may be imposed, which could adversely affect the payment of principal and/or interest on those obligations; (vi) there may be less publicly available information concerning foreign banks issuing the obligations; and (vii) the reserve requirements and accounting, auditing and financial reporting standards, practices and requirements applicable to foreign banks may differ (including by being less stringent) from those applicable to domestic banks. Foreign banks generally are not subject to examination by any U.S. Government agency or instrumentality. See Permissible Fund Investments — Foreign Securities.

Although one or more of the other risks described in this SAI may also apply, the risks typically associated with bank obligations include: Counterparty Risk, Credit Risk, Interest Rate Risk, Issuer Risk, Liquidity Risk and Prepayment and Extension Risk. See Information Regarding Risks.

Collateralized Bond Obligations

Collateralized bond obligations (CBOs) are investment grade bonds backed by a pool of bonds, which may include junk bonds (which are considered speculative investments). CBOs are similar in concept to collateralized mortgage obligations (CMOs), but differ in that CBOs represent different degrees of credit quality rather than different maturities. (See Permissible Fund Investments — Mortgage-Backed Securities and — Asset-Backed Securities). CBOs are often privately offered and sold, and thus not registered under the federal securities laws.

Underwriters of CBOs package a large and diversified pool of high-risk, high-yield junk bonds, which is then structured into “tranches.” Typically, the first tranche represents a senior claim on collateral and pays the lowest interest rate; the second tranche is junior to the first tranche and therefore subject to greater risk and pays a higher rate; the third tranche is junior to both the first and second tranche, represents the lowest credit quality and instead of receiving a fixed interest rate receives the residual interest payments — money that is left over after the higher tranches have been paid. CBOs, like CMOs, are substantially over-collateralized and this, plus the diversification of the pool backing them, may earn certain of the tranches investment-grade bond ratings. Holders of third-tranche CBOs stand to earn higher or lower yields depending on the rate of defaults in the collateral pool. See Permissible Fund Investments — High-Yield Securities.

Although one or more of the other risks described in this SAI may also apply, the risks typically associated with CBOs include: Credit Risk, Interest Rate Risk, Liquidity Risk, High-Yield Securities Risk and Prepayment and Extension Risk. See Information Regarding Risks.

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Commercial Paper

Commercial paper is a short-term debt obligation, usually sold on a discount basis, with a maturity ranging from 2 to 270 days issued by banks, corporations and other borrowers. It is sold to investors with temporary idle cash as a way to increase returns on a short-term basis. These instruments are generally unsecured, which increases the credit risk associated with this type of investment. See Permissible Fund Investments — Debt Obligations and — Illiquid Investments.

Although one or more of the other risks described in this SAI may also apply, the risks typically associated with commercial paper include: Credit Risk and Liquidity Risk. See Information Regarding Risks.

Common Stock

Common stock represents a unit of equity ownership of a corporation. Owners typically are entitled to vote on the selection of directors and other important corporate governance matters, and to receive dividend

payments, if any, on their holdings. However, ownership of common stock does not entitle owners to participate in the day-to-day operations of the corporation. Common stocks of domestic and foreign public corporations can be listed, and their shares traded, on domestic stock exchanges, such as the NYSE or the NASDAQ Stock Market. Domestic and foreign corporations also may have their shares traded on foreign exchanges, such as the London Stock Exchange or Tokyo Stock Exchange. See Permissible Fund Investments — Foreign Securities. Common stock may be privately placed or publicly offered. The price of common stock is generally determined by corporate earnings, type of products or services offered, projected growth rates, experience of management, liquidity, and market conditions generally. In the event that a corporation declares bankruptcy or is liquidated, the claims of secured and unsecured creditors and owners of bonds and preferred stock take precedence over the claims of those who own common stock. See Permissible Fund Investments — Private Placement and Other Restricted Securities — Preferred Stock and — Convertible Securities for more information.

Although one or more of the other risks described in this SAI may also apply, the risks typically associated with common stock include: Issuer Risk and Market Risk. See Information Regarding Risks.

Convertible Securities

Convertible securities include bonds, debentures, notes, preferred stocks or other securities that may be converted or exchanged (by the holder or by the issuer) into shares of the underlying common stock (or cash or securities of equivalent value) at a stated exchange ratio or predetermined price (the conversion price). As such, convertible securities combine the investment characteristics of debt securities and equity securities. A holder of convertible securities is entitled to receive the income of a bond, debenture or note or the dividend of a preferred stock until the conversion privilege is exercised. The market value of convertible securities generally is a function of, among other factors, interest rates, the rates of return of similar nonconvertible securities and the financial strength of the issuer. The market value of convertible securities tends to decline as interest rates rise and, conversely, to rise as interest rates decline. However, a convertible security’s market value tends to reflect the market price of the common stock of the issuing company when that stock price approaches or is greater than its conversion price. As the market price of the underlying common stock declines, the price of the convertible security tends to be influenced more by the rate of return of the convertible security. Because both interest rate and common stock market movements can influence their value, convertible securities generally are not as sensitive to changes in interest rates as similar non-convertible debt securities nor generally as sensitive to changes in share price as the underlying common stock. Convertible securities may be structured as fixed-, variable- or floating-rate obligations or as zero-coupon, pay-in-kind and step-coupon securities and may be privately placed or publicly offered. See Permissible Fund Investments — Variable- and Floating-Rate Obligations, — Debt Obligations — Zero-Coupon, Pay-in-Kind and Step-Coupon Securities, — Common Stock, — Corporate Debt Securities and — Private Placement and Other Restricted Securities for more information.

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Certain convertible securities may have a mandatory conversion feature, pursuant to which the securities convert automatically into common stock or other equity securities (of the same or a different issuer) at a specified date and at a specified exchange ratio. Certain convertible securities may be convertible at the option of the issuer, which may require a holder to convert the security into the underlying common stock, even at times when the value of the underlying common stock or other equity security has declined substantially. In addition, some convertible securities may be rated below investment grade or may not be rated and, therefore, may be considered speculative investments. Companies that issue convertible securities frequently are small- and mid-capitalization companies and, accordingly, carry the risks associated with such companies. In addition, the credit rating of a company’s convertible securities generally is lower than that of its conventional debt securities. Convertible securities are senior to equity securities and have a claim to the assets of an issuer prior to the holders of the issuer’s common stock in the event of liquidation but generally are subordinate to similar non-convertible debt securities of the same issuer. Some convertible securities are particularly sensitive to changes in interest rates when their predetermined conversion price is much higher than the price for the issuing company’s common stock.

Although one or more of the other risks described in this SAI may also apply, the risks typically associated with convertible securities include: Convertible Securities Risk, Interest Rate Risk, Issuer Risk, Market Risk, Prepayment and Extension Risk and Reinvestment Risk. See Information Regarding Risks.

Corporate Debt Securities

Corporate debt securities are long and short term fixed income securities typically issued by businesses to finance their operations. Corporate debt securities are issued by public or private companies, as distinct from debt securities issued by a government or its agencies. The issuer of a corporate debt security often has a contractual obligation to pay interest at a stated rate on specific dates and to repay principal periodically or on a specified maturity date. Corporate debt securities typically have four distinguishing features: (i) they are taxable; (ii) they have a par value of $1,000; (iii) they have a term maturity, which means they come due at a specified time period; and (iv) many are traded on major securities exchanges. Notes, bonds, debentures and commercial paper are the most common types of corporate debt securities, with the primary difference being their interest rates, maturity dates and secured or unsecured status. Commercial paper has the shortest term and usually is unsecured, as are debentures. The broad category of corporate debt securities includes debt issued by domestic or foreign companies of all kinds, including those with small-, mid- and large-capitalizations. The category also includes bank loans, as well as assignments, participations and other interests in bank loans. Corporate debt securities may be rated investment grade or below investment grade and may be structured as fixed-, variable- or floating-rate obligations or as zero-coupon, pay-in-kind and step-coupon securities and may be privately placed or publicly offered. They may also be senior or subordinated obligations. See Appendix A for a discussion of securities ratings. See Permissible Fund Investments — Variable- and Floating-Rate Obligations, — Private Placement and Other Restricted Securities, — Debt Obligations, — Commercial Paper and — High Yield Securities for more information.

Extendible commercial notes (ECNs) are very similar to commercial paper except that with ECNs, the issuer has the option to extend the notes’ maturity. ECNs are issued at a discount rate, with an initial redemption of not more than 90 days from the date of issue. If ECNs are not redeemed by the issuer on the initial redemption date, the issuer will pay a premium (step-up) rate based on the ECN’s credit rating at the time.

Because of the wide range of types and maturities of corporate debt securities, as well as the range of creditworthiness of issuers, corporate debt securities can have widely varying risk/return profiles. For example, commercial paper issued by a large established domestic corporation that is rated by an NRSRO as investment grade may have a relatively modest return on principal but present relatively limited risk. On the other hand, a long-term corporate note issued, for example, by a small foreign corporation from an emerging market country that has not been rated by an NRSRO may have the potential for relatively large returns on principal but carries a relatively high degree of risk.

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Although one or more of the other risks described in this SAI may also apply, the risks typically associated with corporate debt securities include: Credit Risk, Interest Rate Risk, Issuer Risk, High Yield Securities Risk, Prepayment and Extension Risk and Reinvestment Risk. See Information Regarding Risks.

Custody Receipts and Trust Certificates

Custody receipts and trust certificates are derivative products that evidence direct ownership in a pool of securities. Typically, a sponsor will deposit a pool of securities with a custodian in exchange for custody receipts evidencing interests in those securities. The sponsor generally then will sell the custody receipts or trust certificates in negotiated transactions at varying prices. Each custody receipt or trust certificate evidences the individual securities in the pool and the holder of a custody receipt or trust certificate generally will have all the rights and privileges of owners of those securities.

Although one or more of the other risks described in this SAI may also apply, the risks typically associated with custody receipts and trust certificates include: Liquidity Risk and Counterparty Risk. See Information Regarding Risks. In addition, custody receipts and trust certificates generally are subject to the same risks as the securities evidenced by the receipts or certificates.

Debt Obligations

Many different types of debt obligations exist (for example, bills, bonds, and notes). Issuers of debt obligations have a contractual obligation to pay interest at a fixed, variable or floating rate on specified dates and to repay principal by a specified maturity date. Certain debt obligations (usually intermediate and long-term bonds) have provisions that allow the issuer to redeem or “call” a bond before its maturity. Issuers are most likely to call these securities during periods of falling interest rates. When this happens, an investor may have to replace these securities with lower yielding securities, which could result in a lower return.

The market value of debt obligations is affected primarily by changes in prevailing interest rates and the issuer’s perceived ability to repay the debt. The market value of a debt obligation generally reacts inversely to interest rate changes. When prevailing interest rates decline, the market value of the bond usually rises, and when prevailing interest rates rise, the market value of the bond usually declines.

In general, the longer the maturity of a debt obligation, the higher its yield and the greater the sensitivity to changes in interest rates. Conversely, the shorter the maturity, the lower the yield and the lower the sensitivity to changes in interest rates.

As noted, the values of debt obligations also may be affected by changes in the credit rating or financial condition of their issuers. Generally, the lower the quality rating of a security, the higher the degree of risk as to the payment of interest and return of principal. To compensate investors for taking on such increased risk, those issuers deemed to be less creditworthy generally must offer their investors higher interest rates than do issuers with better credit ratings. See Permissible Fund Investments — Corporate Debt Securities and — High Yield Securities.

Stripped Securities

Stripped securities are the separate income or principal payments of a debt security and evidence ownership in either the future interest or principal payments on an instrument. There are many different types and variations of stripped securities. For example, Separate Trading of Registered Interest and Principal Securities (STRIPS) can be component parts of a U.S. Treasury security where the principal and interest components are traded independently through DTC, a clearing agency registered pursuant to Section 17A of the 1934 Act, and created to hold securities for its participants, and to facilitate the clearance and settlement of securities transactions between participants through electronic computerized book-entries, thereby eliminating the need for physical movement of certificates. Treasury Investor Growth Receipts (TIGERs) are U.S. Treasury securities stripped by brokers.

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Stripped mortgage-backed securities (SMBS) also can be issued by the U.S. Government or its agencies. Stripped securities may be structured as fixed-, variable- or floating-rate obligations. See Permissible Fund Investments — Variable- and Floating-Rate Obligations for more information.

SMBS usually are structured with two or more classes that receive different proportions of the interest and principal distributions from a pool of mortgage-backed assets. Common types of SMBS will be structured so that one class receives some of the interest and most of the principal from the mortgage backed assets, while another class receives most of the interest and the remainder of the principal.

Although one or more of the other risks described in this SAI may also apply, the risks typically associated with stripped securities include: Credit Risk, Interest Rate Risk, Liquidity Risk, Prepayment and Extension Risk and Stripped Securities Risk. See Information Regarding Risks.

When-Issued, Delayed Delivery and Forward Commitment Transactions

When-issued, delayed delivery and forward commitment transactions involve the purchase or sale of securities by a Fund, with payment and delivery taking place in the future after the customary settlement period for that type of security. Normally, the settlement date occurs within 45 days of the purchase although in some cases settlement may take longer. The investor does not pay for the securities or receive dividends or interest on them until the contractual settlement date. When engaging in when issued, delayed delivery and forward commitment transactions, a Fund generally will designate on its books and records cash or liquid securities in an amount at least equal to the maximum potential future payment obligations of the Fund related to such transactions. The payment obligation and, if applicable, the interest rate that will be received on the securities, are fixed at the time that a Fund agrees to purchase the securities. A Fund generally will enter into when-issued, delayed delivery and forward commitment transactions only with the intention of completing such transactions. However, the Investment Manager may determine not to complete a transaction if it deems it appropriate to close out the transaction prior to its completion. In such cases, a Fund may realize short-term gains or losses.

To Be Announced Securities (TBAs). As with other delayed delivery transactions, a seller agrees to issue a TBA security at a future date. However, the seller does not specify the particular securities to be delivered. Instead, the Fund agrees to accept any security that meets specified terms. For example, in a TBA mortgage-backed security transaction, the Fund and the seller would agree upon the issuer, interest rate and terms of the underlying mortgages. The seller would not identify the specific underlying mortgages until it issues the security. TBA mortgage-backed securities increase market risks because the underlying mortgages may be less favorable than anticipated by the Fund. See Types of Investments — Mortgage-Backed Securities and — Asset-Backed Securities. In order to better define contractual rights and to secure rights that will help a Fund mitigate its counterparty risk, TBA transactions may be entered into by a Fund under Master Securities Forward Transaction Agreements (each, an “MSFTA”). An MSFTA typically contains, among other things, collateral posting terms and netting provisions in the event of default and/or termination event. The collateral requirements are typically calculated by netting the mark-to-market amount for each transaction under such agreement and comparing that amount to the value of the collateral currently pledged by a fund and the counterparty. To the extent amounts due to a Fund are not fully collateralized, contractually or otherwise, a Fund bears the risk of loss from counterparty non-performance.

Although one or more of the other risks described in this SAI may also apply, the risks typically associated with when-issued, delayed delivery and forward commitment transactions include: Counterparty Risk, Credit Risk and Market Risk. See Information Regarding Risks.

Zero-Coupon, Pay-in-Kind and Step-Coupon Securities

Zero-coupon, pay-in-kind and step-coupon securities are types of debt instruments that do not necessarily make payments of interest in fixed amounts or at fixed intervals. Asset-backed securities, convertible securities,

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corporate debt securities, foreign securities, high yield securities, mortgage-backed securities, municipal securities, participation interests, stripped securities, U.S. Government and related obligations and other types of debt instruments may be structured as zero-coupon, pay-in-kind and step coupon securities. Zero-coupon securities do not pay interest on a current basis but instead accrue interest over the life of the security. These securities include, among others, zero-coupon bonds, which either may be issued at a discount by a corporation or government entity or may be created by a brokerage firm when it strips the coupons from a bond or note and then sells the bond or note and the coupon separately. This technique is used frequently with U.S. Treasury bonds, and zero-coupon securities are marketed under such names as CATS (Certificate of Accrual on Treasury Securities), TIGERs or STRIPS. Zero-coupon bonds also are issued by municipalities. Buying a municipal zero coupon bond frees its purchaser of the obligation to pay regular federal income tax on imputed interest, since the interest is exempt for regular federal income tax purposes. Zero-coupon certificates of deposit and zero-coupon mortgages are generally structured in the same fashion as zero-coupon bonds; the certificate of deposit holder or mortgage holder receives face value at maturity and no payments until then.

Pay-in-kind securities normally give the issuer an option to pay cash at a coupon payment date or to give the holder of the security a similar security with the same coupon rate and a face value equal to the amount of the coupon payment that would have been made.

Step-coupon securities trade at a discount from their face value and pay coupon interest that gradually increases over time. The coupon rate is paid according to a schedule for a series of periods, typically lower for an initial period and then increasing to a higher coupon rate thereafter. The discount from the face amount or par value depends on the time remaining until cash payments begin, prevailing interest rates, liquidity of the security and the perceived credit quality of the issue.

Zero-coupon, step-coupon and pay-in-kind securities holders generally have substantially all the rights and privileges of holders of the underlying coupon obligations or principal obligations. Holders of these securities typically have the right upon default on the underlying coupon obligations or principal obligations to proceed directly and individually against the issuer and are not required to act in concert with other holders of such securities.

See Appendix A for a discussion of securities ratings.

Although one or more of the other risks described in this SAI may also apply, the risks typically associated with zero-coupon, step-coupon and pay-in-kind securities include: Credit Risk, Interest Rate Risk and Zero- Coupon Bonds Risk. See Information Regarding Risks.

Determining Investment Grade for Purposes of Investment Policies. Unless otherwise stated in a Fund’s prospectus, when determining, under a Fund’s investment policies, whether a debt instrument is investment grade or below investment grade for purposes of purchase by a Fund, or a Portfolio Fund, the Fund and the Portfolio Funds will apply a particular credit quality rating methodology as described within the Fund’s or Portfolio Fund’s shareholder reports, when available. These methodologies typically make use of credit quality ratings assigned by a third-party rating agency or agencies, when available. Credit quality ratings assigned by a rating agency are subjective opinions, not statements of fact, and are subject to change, including daily. Credit quality ratings apply to a Fund’s or Portfolio Fund’s debt instrument investments and not the Fund or Portfolio Fund itself.

Ratings limitations under a Fund’s or a Portfolio Fund’s investment policies are applied at the time of purchase by a Fund or Portfolio Fund. Subsequent to purchase, a debt instrument may cease to be rated by a rating agency or its rating may be reduced by one more rating agencies below the minimum required for purchase by a Fund. Neither event will require the sale of such debt instrument, but it may be a factor in considering whether to continue to hold the instrument. Unless otherwise stated in a Fund’s or a Portfolio Fund’s prospectus or in this SAI, a Fund or a Portfolio Fund may invest in debt instruments that are not rated by a rating agency.

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When a debt instrument is not rated by a rating agency, the Investment Manager or, as applicable, the investment adviser to a Portfolio Fund or a Portfolio Fund subadviser determines, at the time of purchase, whether such debt instrument is of investment grade or below investment grade (e.g., junk bond) quality. A Fund’s or Portfolio Fund’s debt instrument holdings that are not rated by a rating agency are typically referred to as “Not Rated” within the Fund’s shareholder reports.

See Appendix A for a discussion of securities ratings.

Although one or more of the other risks described in this SAI may also apply, the risks typically associated with debt obligations include: Confidential Information Access Risk, Credit Risk, Highly Leveraged Transactions Risk, Impairment of Collateral Risk, Interest Rate Risk, Issuer Risk, Liquidity Risk, Prepayment and Extension Risk and Reinvestment Risk. See Information Regarding Risks.

Determining Average Maturity. When determining the average maturity of a Fund’s or a Portfolio Fund’s portfolio, the Investment Manager or the Portfolio Fund’s investment adviser may use the effective maturity of a portfolio security by, among other things, adjusting for interest rate reset dates, call dates or “put” dates.

Depositary Receipts

See Permissible Fund Investments — Foreign Securities.

Derivatives

General

Derivatives are financial instruments whose values are based on (or “derived” from) traditional securities (such as a stock or a bond), assets (such as a commodity, like gold), reference rates (such as SOFR or LIBOR, which is being phased out), market indices (such as the S&P 500^® Index), or customized baskets of securities or instruments. Some forms of derivatives, such as exchange-traded futures and options on securities, commodities, or indices, are traded on regulated exchanges. Exchange-traded derivatives are standardized contracts. Usually, these contracts can easily be bought and sold, and have a market value that is determined and published daily. Although, as subsequently discussed in the risk disclosures in this Statement of Additional Information, there may be disruptions with respect to liquidity and pricing of exchange-traded derivatives. See, for example, Derivatives Risk — Futures Contracts Risk. Non-standardized derivatives, on the other hand, tend to be more specialized or complex, and may be harder to value. Many derivative instruments often require little or no initial payment and therefore often create inherent economic leverage. Derivatives, when used properly, can enhance returns and be useful in hedging portfolios and managing risk. Some common types of derivatives include futures; options; options on futures; forward foreign currency exchange contracts; forward contracts on securities and securities indices; linked securities and structured products; collateralized mortgage obligations (CMOs); swap agreements and swaptions.

Some derivatives require payments relating to the actual, future delivery of one or more securities, assets, currencies, commodities or instruments. These types of derivatives are frequently referred to as “physically settled” derivatives. Other derivatives require payments relating to the income or returns from, or changes in the market value of, one or more securities, assets, currencies, commodities or instruments. These types of derivatives are known as “cash settled” derivatives, since they require cash payments in lieu of delivery of the particular securities, assets, currencies, commodities or instruments. Any derivative can be structured so that it is physically settled or cash settled, although derivatives that relate to changes in the value of a particular index or reference rate are most often cash-settled.

Generally, for physically-settled contracts, in compliance with so-called “asset segregation” regulatory requirements, cash or liquid securities at least equal in value to the maximum potential future payment obligations of a Fund under the contract (less any applicable margin deposits or postings) generally will be

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designated on the Fund’s books and records. But, for cash-settled contracts, the Fund will designate cash or liquid securities equal to the Fund’s daily marked-to-market (net) obligations, if any (i.e., the Fund’s daily net liability, if any), rather than its maximum potential future payment obligation under the contract. The Fund’s specific approach to certain derivatives is discussed in greater detail below.

A Fund may use derivatives for a variety of reasons, including, for example: (i) to enhance its return; (ii) to attempt to protect against possible unfavorable changes in the market value of securities held in or to be purchased for its portfolio resulting from securities markets or currency exchange rate fluctuations (i.e., to hedge); (iii) to protect its unrealized gains reflected in the value of its portfolio securities; (iv) to facilitate the sale of such securities for investment purposes; (v) to reduce transaction costs; (vi) to manage the effective maturity or duration of its portfolio; and/or (vii) to maintain cash reserves while remaining fully invested.

The Funds may employ portfolio margining with respect to derivatives investments, which creates leverage in a Fund’s portfolio (subjecting the Fund to Leverage Risk). Portfolio margining is a methodology that computes margin requirements for an account based on the greatest projected net loss of all positions in a product class or group, and uses computer modeling to perform risk analysis using multiple pricing scenarios. The pricing scenarios are designed to measure the theoretical loss of the positions, given changes in the underlying price and implied volatility inputs to the model. Accordingly, the margin required is based on the greatest loss that would be incurred in a portfolio if the value of its components move up or down by a predetermined amount.

A Fund may use any or all of the above investment techniques and may purchase different types of derivative instruments at any time and in any combination. The use of derivatives is a function of numerous variables, including market conditions. See also Permissible Fund Investments — Warrants and Rights and Debt Obligations — When Issued, Delayed Delivery and Forward Commitment Transactions.

Although one or more of the other risks described in this SAI may also apply, the risks typically associated with transactions in derivatives (including the derivatives instruments discussed below) include: Counterparty Risk, Credit Risk, Interest Rate Risk, Leverage Risk, Liquidity Risk, Market Risk, Derivatives Risk, Derivatives Risk/Forward Contracts Risk, Derivatives Risk/Futures Contracts Risk, Derivatives Risk/Inverse Floaters Risk, Derivatives Risk/Options Risk, Derivatives Risk/Structured Investments Risk, and Derivatives Risk/Swaps Risk. See Information Regarding Risks.

Structured Investments (Indexed or Linked Securities)

General. Indexed or linked securities, also often referred to as “structured products,” are instruments that may have varying combinations of equity and debt characteristics. These instruments are structured to recast the investment characteristics of the underlying security or reference asset. If the issuer is a unit investment trust or other special purpose vehicle, the structuring will typically involve the deposit with or purchase by such issuer of specified instruments (such as commercial bank loans or securities) and/or the execution of various derivative transactions, and the issuance by that entity of one or more classes of securities (structured securities) backed by, or representing interests in, the underlying instruments. The cash flow on the underlying instruments may be apportioned among the newly issued structured securities to create securities with different investment characteristics, such as varying maturities, payment priorities and interest rate provisions, and the extent of such payments made with respect to structured securities is dependent on the extent of the cash flow on the underlying instruments.

Indexed and Inverse Floating Rate Securities. A Fund may invest in securities that provide a potential return based on a particular index or interest rates. For example, a Fund may invest in debt securities that pay interest based on an index of interest rates. The principal amount payable upon maturity of certain securities also may be based on the value of the index. To the extent a Fund invests in these types of securities, a Fund’s return on such securities will rise and fall with the value of the particular index: that is, if the value of the index falls, the value of the indexed securities owned by a Fund will fall. Interest and principal payable on certain securities may also be based on relative changes among particular indices.

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A Fund may also invest in so-called “inverse floaters” or “residual interest bonds” on which the interest rates vary inversely with a floating rate (which may be reset periodically by a dutch auction, a remarketing agent, or by reference to a short-term tax-exempt interest rate index). A Fund may purchase synthetically-created inverse floating rate bonds evidenced by custodial or trust receipts. A trust funds the purchase of a bond by issuing two classes of certificates: short-term floating rate notes (typically sold to third parties) and the inverse floaters (also known as residual certificates). No additional income beyond that provided by the trust’s underlying bond is created; rather, that income is merely divided-up between the two classes of certificates. Generally, income on inverse floating rate bonds will decrease when interest rates increase, and will increase when interest rates decrease. Such securities can have the effect of providing a degree of investment leverage, since they may increase or decrease in value in response to changes in market interest rates at a rate that is a multiple of the actual rate at which fixed-rate securities increase or decrease in response to such changes. As a result, the market values of such securities will generally be more volatile than the market values of fixed-rate securities. To seek to limit the volatility of these securities, a Fund may purchase inverse floating obligations that have shorter-term maturities or that contain limitations on the extent to which the interest rate may vary. Certain investments in such obligations may be illiquid. Furthermore, where such a security includes a contingent liability, in the event of an adverse movement in the underlying index or interest rate, a Fund may be required to pay substantial additional margin to maintain the position.

Credit-Linked Securities. Among the income-producing securities in which a Fund may invest are credit- linked securities. The issuers of these securities frequently are limited purpose trusts or other special purpose vehicles that, in turn, invest in a derivative instrument or basket of derivative instruments, such as credit default swaps, interest rate swaps and other securities, in order to provide exposure to certain fixed income markets. For instance, a Fund may invest in credit-linked securities as a cash management tool in order to gain exposure to a certain market and/or to remain fully invested when more traditional income-producing securities are not available. Like an investment in a bond, investments in these credit-linked securities represent the right to receive periodic income payments (in the form of distributions) and payment of principal at the end of the term of the security. However, these payments are conditioned on or linked to the issuer’s receipt of payments from, and the issuer’s potential obligations to, the counterparties to the derivative instruments and other securities in which the issuer invests. For instance, the issuer may sell one or more credit default swaps, under which the issuer would receive a stream of payments over the term of the swap agreements provided that no event of default has occurred with respect to the referenced debt obligation upon which the swap is based. If a default occurs, the stream of payments may stop and the issuer would be obligated to pay the counterparty the par (or other agreed upon value) of the referenced debt obligation. This, in turn, would reduce the amount of income and/or principal that a Fund would receive. A Fund’s investments in these securities are indirectly subject to the risks associated with derivative instruments. These securities generally are exempt from registration under the 1933 Act. Accordingly, there may be no established trading market for the securities and they may be illiquid.

Equity-Linked Notes. An equity-linked note (ELN) is a debt instrument whose value is based on the value of a single equity security, basket of equity securities or an index of equity securities (each, an Underlying Equity). An ELN typically provides interest income, thereby offering a yield advantage over investing directly in an Underlying Equity. A Fund may purchase ELNs that trade on a securities exchange or those that trade on the over-the-counter markets, including Rule 144A securities. A Fund may also purchase ELNs in a privately negotiated transaction with the issuer of the ELNs (or its broker-dealer affiliate). A Fund may or may not hold an ELN until its maturity.

Equity-linked securities also include issues such as Structured Yield Product Exchangeable for Stock (STRYPES), Trust Automatic Common Exchange Securities (TRACES), Trust Issued Mandatory Exchange Securities (TIMES) and Trust Enhanced Dividend Securities (TRENDS). The issuers of these equity-linked securities generally purchase and hold a portfolio of stripped U.S. Treasury securities maturing on a quarterly basis through the conversion date, and a forward purchase contract with an existing shareholder of the company relating to the common stock. Quarterly distributions on such equity linked securities generally consist of the cash received from the U.S. Treasury securities and such equity-linked securities generally are not entitled to any dividends that may be declared on the common stock.

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ELNs also include participation notes issued by a bank or broker-dealer that entitles a Fund to a return measured by the change in value of an Underlying Equity. Participation notes are typically used when a direct investment in the Underlying Equity is restricted due to country specific regulations. Investment in a participation note is not the same as investment in the constituent shares of the company (or other issuer type) to which the Underlying Equity is economically tied. A participation note represents only an obligation of the company or other issuer type to provide a Fund the economic performance equivalent to holding shares of the Underlying Equity. A participation note does not provide any beneficial or equitable entitlement or interest in the relevant Underlying Equity. In other words, shares of the Underlying Equity are not in any way owned by a Fund.

Although one or more of the other risks described in this SAI may also apply, the risks typically associated with equity-linked notes include: Counterparty Risk, Credit Risk, Liquidity Risk and Market Risk.

Index-, Commodity- and Currency-Linked Securities. “Index-linked” or “commodity-linked” notes are debt securities of companies that call for interest payments and/or payment at maturity in different terms than the typical note where the borrower agrees to make fixed interest payments and to pay a fixed sum at maturity. Principal and/or interest payments on an index-linked or commodity-linked note depend on the performance of one or more market indices, such as the S&P 500^® Index, a weighted index of commodity futures such as crude oil, gasoline and natural gas or the market prices of a particular commodity or basket of commodities or securities. Currency-linked debt securities are short-term or intermediate-term instruments having a value at maturity, and/or an interest rate, determined by reference to one or more foreign currencies. Payment of principal or periodic interest may be calculated as a multiple of the movement of one currency against another currency, or against an index.

Index-, commodity- and currency-linked securities may entail substantial risks. Such instruments may be subject to significant price volatility. The company issuing the instrument may fail to pay the amount due on maturity. The underlying investment may not perform as expected by the Investment Manager. Markets and underlying investments and indexes may move in a direction that was not anticipated by the Investment Manager. Performance of the derivatives may be influenced by interest rate and other market changes in the United States and abroad, and certain derivative instruments may be illiquid.

Linked securities are often issued by unit investment trusts. Examples of this include such index-linked securities as S&P Depositary Receipts (SPDRs), which is an interest in a unit investment trust holding a portfolio of securities linked to the S&P 500^® Index, and a type of exchange-traded fund (ETF). Because a unit investment trust is an investment company under the 1940 Act, a Fund’s investments in SPDRs are subject to the limitations set forth in Section 12(d)(1)(A) of the 1940 Act, although the SEC has issued exemptive relief permitting investment companies such as the Funds to invest beyond the limits of Section 12(d)(1)(A) subject to certain conditions. SPDRs generally closely track the underlying portfolio of securities, trade like a share of common stock and pay periodic dividends proportionate to those paid by the portfolio of stocks that comprise the S&P 500^® Index. As a holder of interests in a unit investment trust, a Fund would indirectly bear its ratable share of that unit investment trust’s expenses. At the same time, a Fund would continue to pay its own management and advisory fees and other expenses, as a result of which a Fund and its shareholders in effect would be absorbing levels of fees with respect to investments in such unit investment trusts.

Because linked securities typically involve no credit enhancement, their credit risk generally will be equivalent to that of the underlying instruments. Investments in structured products may be structured as a class that is either subordinated or unsubordinated to the right of payment of another class. Subordinated linked securities typically have higher rates of return and present greater risks than unsubordinated structured products. Structured products sometimes are sold in private placement transactions and often have a limited trading market.

Investments in linked securities have the potential to lead to significant losses because of unexpected movements in the underlying financial asset, index, currency or other investment. The ability of a Fund to utilize linked-securities successfully will depend on its ability correctly to predict pertinent market movements, which

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cannot be assured. Because currency-linked securities usually relate to foreign currencies, some of which may be currencies from emerging market countries, there are certain additional risks associated with such investments.

Futures Contracts and Options on Futures Contracts

Futures Contracts. A futures contract can be physically settled or cash settled. If physically settled, then the sale of a futures contract (the “short position” in the contract) creates an obligation by the seller to deliver the type of security or other asset called for in the contract at a specified delivery time for a stated price. Conversely, the purchase of a physically-settled futures contract (the “long position” in the contract) creates an obligation by the purchaser to take delivery of the type of security or other asset called for in the contract at a specified delivery time for a stated price. The specific security or other asset delivered or taken at the settlement date is not determined until on or near that date. If a futures contract is cash-settled, then a party will make or receive a payment, depending upon whether it holds the short or long position in the particular contract. Specifically, the party that holds the short position receives (makes) payments when the market value of the underlying security, asset, currency, commodity or instrument decreases (increases) in value, whereas a party that holds the long position receives (makes) payments when that market value increases (decreases). The determination as to whether a futures contract is physically or cash settled (as wells as the particular assets or securities that can be delivered upon settlement of a physically settled contract) is made in accordance with the rules of the exchange on which the futures contract was made. A Fund may enter into futures contracts which are traded on national or foreign futures exchanges and are standardized as to maturity date and underlying security or other asset. Futures exchanges and trading in the United States are regulated under the CEA by the CFTC a U.S. Government agency. See Permissible Fund Investments — Derivatives — CFTC Regulation below for information on CFTC regulation.

Traders in futures contracts may be broadly classified as either “hedgers” or “speculators.” Hedgers use the futures markets primarily to offset unfavorable changes (anticipated or potential) in the value of securities or other assets currently owned or expected to be acquired by them. Speculators less often own the securities or other assets underlying the futures contracts which they trade, and generally use futures contracts with the expectation of realizing profits from fluctuations in the value of the underlying securities or other assets.

Upon entering into futures contracts, in compliance with regulatory requirements, cash or liquid securities generally will be designated on the Fund’s books and records.

Unlike when a Fund purchases or sells a security, no price is paid or received by a Fund upon the purchase or sale of a futures contract, although a Fund is required to deposit in a segregated or designated account with its futures broker an amount of cash and/or U.S. Government securities in order to initiate and maintain open positions in futures contracts. This amount is known as “initial margin.” The nature of initial margin in futures transactions is different from that of margin in security transactions, in that futures contract margin does not involve the borrowing of funds by a Fund to finance the transactions. Rather, initial margin is in the nature of a performance bond or good faith deposit intended to assure completion of the contract (delivery or acceptance of the underlying security or other asset) that is returned to a Fund upon termination of the futures contract, assuming all contractual obligations have been satisfied. Minimum initial margin requirements are established by the relevant futures exchange and may be changed. Brokers may establish deposit requirements which are higher than the exchange minimums. Futures contracts are customarily purchased and sold on margin which may range upward from less than 5% of the value of the contract being traded. Subsequent payments, called “variation margin,” to and from the broker (or the custodian) are made on a daily basis as the price of the underlying security or other asset fluctuates, a process known as “marking to market.” If the futures contract price changes to the extent that the margin on deposit does not satisfy margin requirements, payment of additional variation margin will be required. Conversely, a change in the contract value may reduce the required margin, resulting in a repayment of excess margin to the contract holder. Variation margin payments are made for as long as the contract remains open. A Fund expects to earn interest income on its margin deposits.

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Although futures contracts by their terms call for actual delivery or acceptance of securities or other assets (stock index futures contracts or futures contracts that reference other intangible assets do not permit delivery of the referenced assets), the contracts usually are closed out before the settlement date without the making or taking of delivery. A Fund may elect to close some or all of its futures positions at any time prior to their expiration. The purpose of taking such action would be to reduce or eliminate the position then currently held by a Fund. Closing out an open futures position is done by taking an opposite position (“buying” a contract which has previously been “sold,” “selling” a contract previously “purchased”) in an identical contract (i.e., the same aggregate amount of the specific type of security or other asset with the same delivery date) to terminate the position. Final determinations are made as to whether the price of the initial sale of the futures contract exceeds or is below the price of the offsetting purchase, or whether the purchase price exceeds or is below the offsetting sale price. Final determinations of variation margin are then made, additional cash is required to be paid by or released to a Fund, and a Fund realizes a loss or a gain. Brokerage commissions are incurred when a futures contract is bought or sold.

Successful use of futures contracts by a Fund is subject to the Investment Manager’s ability to predict correctly movements in the direction of interest rates and other factors affecting securities and commodities markets. This requires different skills and techniques than those required to predict changes in the prices of individual securities. A Fund, therefore, bears the risk that future market trends will be incorrectly predicted.

The risk of loss in trading futures contracts in some strategies can be substantial, due both to the relatively low margin deposits required and the potential for an extremely high degree of leverage involved in futures contracts. As a result, a relatively small price movement in a futures contract may result in an immediate and substantial loss to the investor. For example, if at the time of purchase, 10% of the value of the futures contract is deposited as margin, a subsequent 10% decrease in the value of the futures contract would result in a total loss of the margin deposit, before any deduction for the transaction costs, if the account were then closed out. A 15% decrease would result in a loss equal to 150% of the original margin deposit if the contract were closed out. Thus, a purchase or sale of a futures contract may result in losses in excess of the amount posted as initial margin for the contract.

In the event of adverse price movements, a Fund would continue to be required to make daily cash payments in order to maintain its required margin. In such a situation, if a Fund has insufficient cash, it may have to sell portfolio securities in order to meet daily margin requirements at a time when it may be disadvantageous to do so. The inability to close the futures position also could have an adverse impact on the ability to hedge effectively.

To reduce or eliminate a hedge position held by a Fund, a Fund may seek to close out a position. The ability to establish and close out positions will be subject to the development and maintenance of a liquid secondary market. It is not certain that this market will develop or continue to exist for a particular futures contract, which may limit a Fund’s ability to realize its profits or limit its losses. Reasons for the absence of a liquid secondary market on an exchange include the following: (i) there may be insufficient trading interest in certain contracts; (ii) restrictions may be imposed by an exchange on opening transactions, closing transactions or both; (iii) trading halts, suspensions or other restrictions may be imposed with respect to particular classes or series of contracts, or underlying securities; (iv) unusual or unforeseen circumstances, such as volume in excess of trading or clearing capability, may interrupt normal operations on an exchange; (v) the facilities of an exchange or a clearing corporation may not at all times be adequate to handle current trading volume; or (vi) one or more exchanges could, for economic or other reasons, decide or be compelled at some future date to discontinue the trading of contracts (or a particular class or series of contracts), in which event the secondary market on that exchange (or in the class or series of contracts) would cease to exist, although outstanding contracts on the exchange that had been issued by a clearing corporation as a result of trades on that exchange would continue to be exercisable in accordance with their terms.

Interest Rate Futures Contracts. An interest rate future is a derivative that is an agreement whereby the buyer and seller agree to the future delivery of an interest-bearing instrument on a specific date at a pre-determined

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price. Examples include Treasury-bill futures, Treasury-bond futures and Eurodollar futures. Some interest rate futures may be an agreement that requires the buyer (seller) to make payments to the seller (buyer) in the future if a particular underlying reference interest rate decreases (increases) over the term of the contract. Accordingly, a Fund may use interest rate futures contracts as a defense, or hedge, against anticipated interest rate changes. A Fund presently could accomplish a similar result to that which it hopes to achieve through the use of interest rate futures contracts by selling bonds with long maturities and investing in bonds with short maturities when interest rates are expected to increase, or conversely, selling bonds with short maturities and investing in bonds with long maturities when interest rates are expected to decline. However, because of the liquidity that is often available in the futures market, the protection is more likely to be achieved, perhaps at a lower cost and without changing the rate of interest being earned by a Fund, through using futures contracts.

Interest rate futures contracts are traded in an auction environment on the floors of several exchanges – principally, the Chicago Board of Trade, the Chicago Mercantile Exchange and the New York Futures Exchange. Each exchange guarantees performance under contract provisions through a clearing corporation, a nonprofit organization managed by the exchange membership. A public market exists in futures contracts covering various financial instruments including long term U.S. Treasury Bonds and Notes; GNMA modified pass-through mortgage backed securities; three-month U.S. Treasury Bills; and ninety-day commercial paper. A Fund may also invest in exchange-traded Eurodollar contracts, which are interest rate futures on the forward level of a reference rate, such as LIBOR or SOFR. These contracts are generally considered liquid securities and trade on the Chicago Mercantile Exchange. Such Eurodollar contracts are generally used to “lock-in” or hedge the future level of short-term rates. A Fund may trade in any interest rate futures contracts for which there exists a public market, including, without limitation, the foregoing instruments.

Index Futures Contracts. A Fund may purchase or sell index futures contracts. Typically, index futures contracts are cash-settled. A Fund may enter into stock index futures contracts, debt index futures contracts, or other index futures contracts appropriate to its objective(s).

Options on Futures Contracts. A Fund may purchase and write call and put options on those futures contracts that it is permitted to buy or sell. A Fund may use such options on futures contracts in lieu of writing options directly on the underlying securities or other assets or purchasing and selling the underlying futures contracts. Such options generally operate in the same manner as options purchased or written directly on the underlying investments. A futures option gives the holder, in return for the premium paid, the right, but not the obligation, to buy from (call) or sell to (put) the writer of the option a futures contract at a specified price at any time during the period of the option. Upon exercise, the writer of the option is obligated to pay the difference between the cash value of the futures contract and the exercise price. Like the buyer or seller of a futures contract, the holder or writer of an option has the right to terminate its position prior to the scheduled expiration of the option by selling or purchasing an option of the same series, at which time the person entering into the closing purchase transaction will realize a gain or loss. There is no guarantee that such closing purchase transactions can be effected.

A Fund generally will enter into written options on futures contracts only when, in compliance with regulatory requirements, it has designated on its books and records cash or liquid securities at least equal in value to the maximum potential future payment obligations under the contract (less any applicable margin deposits or postings). A Fund will be required to deposit initial margin and maintenance margin with respect to put and call options on futures contracts written by it pursuant to brokers’ requirements similar to those described above.

Options on Index Futures Contracts. A Fund may also purchase and sell options on index futures contracts. Options on index futures give the purchaser the right, in return for the premium paid, to assume a position in an index futures contract (a long position if the option is a call and a short position if the option is a put), at a specified exercise price at any time during the period of the option. Upon exercise of the option, the delivery of the futures position by the writer of the option to the holder of the option will be accompanied by delivery of the accumulated balance in the writer’s futures margin account, which represents the amount by which the market

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price of the index futures contract, at exercise, exceeds (in the case of a call) or is less than (in the case of a put) the exercise price of the option on the index future. If an option is exercised on the last trading day prior to the expiration date of the option, the settlement will be made entirely in cash equal to the difference between the exercise price of the option and the closing level of the index on which the future is based on the expiration date. Purchasers of options who fail to exercise their options prior to the exercise date suffer a loss of the premium paid.

Eurodollar and Yankee Dollar Futures Contracts and Options Thereon. Eurodollar futures contracts enable purchasers to obtain a fixed rate for the lending of funds and sellers to obtain a fixed rate for borrowings. A Fund may use Eurodollar futures contracts and options thereon to hedge against changes in a reference rate, such as LIBOR or SOFR, to which many interest rate swaps and fixed income instruments are linked.

Although one or more of the other risks described in this SAI may also apply, the risks typically associated with Eurodollar and Yankee Dollar instruments include: Credit Risk, Foreign Securities Risk, Interest Rate Risk and Issuer Risk. See Information Regarding Risks.

Options on Stocks, Stock Indices and Other Indices

A Fund may purchase and write (i.e., sell) put and call options. Such options may relate to particular stocks or stock indices, and may or may not be listed on a domestic or foreign securities exchange and may or may not be cleared and settled by the Options Clearing Corporation (OCC). Stock index options are put options and call options on various stock indices. In most respects, they are identical to listed options on common stocks.

There is a key difference between stock options and index options in connection with their exercise. In the case of stock options, the underlying security, common stock, is delivered. However, upon the exercise of an index option, settlement does not occur by delivery of the securities comprising the index. The option holder who exercises the index option receives an amount of cash if the closing level of the stock index upon which the option is based is greater than (in the case of a call) or less than (in the case of a put) the exercise price of the option. This amount of cash is equal to the difference between the closing price of the stock index and the exercise price of the option expressed in dollars times a specified multiple. A stock index fluctuates with changes in the market value of the securities included in the index. For example, some stock index options are based on a broad market index, such as the S&P 500^® Index or a narrower market index, such as the S&P 100^® Index. Indices may also be based on an industry or market segment.

A Fund may, for the purpose of hedging its portfolio, subject to applicable securities regulations, purchase and write put and call options on foreign stock indices listed on foreign and domestic stock exchanges. As an alternative to purchasing call and put options on index futures, a Fund may purchase call and put options on the underlying indices themselves. Such options could be used in a manner identical to the use of options on index futures. Options involving securities indices provide the holder with the right to make or receive a cash settlement upon exercise of the option based on movements in the relevant index. Such options must be listed on a national securities exchange and issued by the OCC. Such options may relate to particular securities or to various stock indices, except that a Fund may not write covered options on an index.

Writing Covered Options. A Fund may write covered call options and covered put options on securities held in its portfolio. Call options written by a Fund give the purchaser the right to buy the underlying securities from a Fund at the stated exercise price at any time prior to the expiration date of the option, regardless of the security’s market price; put options give the purchaser the right to sell the underlying securities to a Fund at the stated exercise price at any time prior to the expiration date of the option, regardless of the security’s market price.

A Fund may write covered options, which means that, so long as a Fund is obligated as the writer of a call option, it will own the underlying securities subject to the option (or comparable securities satisfying the cover requirements of securities exchanges). In the case of put options, a Fund will hold liquid assets equal to the price

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to be paid if the option is exercised. In addition, a Fund will be considered to have covered a put or call option if and to the extent that it holds an option that offsets some or all of the risk of the option it has written. A Fund may write combinations of covered puts and calls (straddles) on the same underlying security.

A Fund will receive a premium from writing a put or call option, which increases a Fund’s return on the underlying security if the option expires unexercised or is closed out at a profit. The amount of the premium reflects, among other things, the relationship between the exercise price and the current market value of the underlying security, the volatility of the underlying security, the amount of time remaining until expiration, current interest rates, and the effect of supply and demand in the options market and in the market for the underlying security. By writing a call option, a Fund limits its opportunity to profit from any increase in the market value of the underlying security above the exercise price of the option but continues to bear the risk of a decline in the value of the underlying security. By writing a put option, a Fund assumes the risk that it may be required to purchase the underlying security for an exercise price higher than the security’s then-current market value, resulting in a potential capital loss unless the security subsequently appreciates in value.

A Fund’s obligation to sell an instrument subject to a call option written by it, or to purchase an instrument subject to a put option written by it, may be terminated prior to the expiration date of the option by a Fund’s execution of a closing purchase transaction, which is effected by purchasing on an exchange an offsetting option of the same series (i.e., same underlying instrument, exercise price and expiration date) as the option previously written. A closing purchase transaction will ordinarily be effected in order to realize a profit on an outstanding option, to prevent an underlying instrument from being called, to permit the sale of the underlying instrument or to permit the writing of a new option containing different terms on such underlying instrument. A Fund realizes a profit or loss from a closing purchase transaction if the cost of the transaction (option premium plus transaction costs) is less or more than the premium received from writing the option. Because increases in the market price of a call option generally reflect increases in the market price of the security underlying the option, any loss resulting from a closing purchase transaction may be offset in whole or in part by unrealized appreciation of the underlying security.

If a Fund writes a call option but does not own the underlying security, and when it writes a put option, a Fund may be required to deposit cash or securities with its broker as “margin” or collateral for its obligation to buy or sell the underlying security. As the value of the underlying security varies, a Fund may also have to deposit additional margin with the broker. Margin requirements are complex and are fixed by individual brokers, subject to minimum requirements currently imposed by the Federal Reserve Board and by stock exchanges and other self-regulatory organizations.

Purchasing Put Options. A Fund may purchase put options to protect its portfolio holdings in an underlying security against a decline in market value. Such hedge protection is provided during the life of the put option since a Fund, as holder of the put option, is able to sell the underlying security at the put exercise price regardless of any decline in the underlying security’s market price. For a put option to be profitable, the market price of the underlying security must decline sufficiently below the exercise price to cover the premium and transaction costs. By using put options in this manner, a Fund will reduce any profit it might otherwise have realized from appreciation of the underlying security by the premium paid for the put option and by transaction costs.

Purchasing Call Options. A Fund may purchase call options, including call options to hedge against an increase in the price of securities that a Fund wants ultimately to buy. Such hedge protection is provided during the life of the call option since a Fund, as holder of the call option, is able to buy the underlying security at the exercise price regardless of any increase in the underlying security’s market price. In order for a call option to be profitable, the market price of the underlying security must rise sufficiently above the exercise price to cover the premium and transaction costs. These costs will reduce any profit a Fund might have realized had it bought the underlying security at the time it purchased the call option.

Over-the-Counter (OTC) Options. OTC options (options not traded on exchanges) are generally established through negotiation with the other party to the options contract. A Fund will enter into OTC options transactions

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only with primary dealers in U.S. Government securities and, in the case of OTC options written by a Fund, only pursuant to agreements that will assure that a Fund will at all times have the right to repurchase the option written by it from the dealer at a specified formula price.

Swap Agreements

General

Swap agreements are derivative instruments that can be individually negotiated and structured to include exposure to a variety of different types of investments or market factors. Depending on their structure, swap agreements may increase or decrease a Fund’s exposure to long- or short-term interest rates, foreign currency values, mortgage securities, corporate borrowing rates, or other factors such as security prices or inflation rates. A Fund may enter into a variety of swap agreements, including interest rate, index, commodity, commodity futures, equity, equity index, credit default, bond futures, total return, currency exchange rate and other types of swap agreements such as caps, collars and floors. A Fund also may enter into swaptions, which are options to enter into a swap agreement.

Swap agreements are usually entered into without an upfront payment because the value of each party’s position is the same. The market values of the underlying commitments will change over time, resulting in one of the commitments being worth more than the other and the net market value creating a risk exposure for one party or the other.

In a typical interest rate swap, one party agrees to make regular payments equal to a floating interest rate times a “notional principal amount,” in return for payments equal to a fixed rate times the same amount, for a specified period of time. If a swap agreement provides for payments in different currencies, the parties might agree to exchange notional principal amounts as well. In a total return swap agreement, the non-floating rate side of the swap is based on the total return of an individual security, a basket of securities, an index or another reference asset. Swaps may also depend on other prices or rates, such as the value of an index or mortgage prepayment rates.

In a typical cap or floor agreement, one party agrees to make payments only under specified circumstances, usually in return for payment of a fee by the other party. For example, the buyer of an interest rate cap obtains the right to receive payments to the extent that a specified interest rate exceeds an agreed-upon level, while the seller of an interest rate floor is obligated to make payments to the extent that a specified interest rate falls below an agreed-upon level. Caps and floors have an effect similar to buying or writing options. A collar combines elements of buying a cap and selling a floor. In interest rate collar transactions, one party sells a cap and purchases a floor, or vice versa, in an attempt to protect itself against interest rate movements exceeding given minimum or maximum levels or collar amounts.

Swap agreements will tend to shift a Fund’s investment exposure from one type of investment to another. For example, if a Fund agreed to pay fixed rates in exchange for floating rates while holding fixed-rate bonds, the swap would tend to decrease a Fund’s exposure to long-term interest rates. Another example is if a Fund agreed to exchange payments in dollars for payments in foreign currency. In that case, the swap agreement would tend to decrease a Fund’s exposure to U.S. interest rates and increase its exposure to foreign currency and interest rates.

Because swaps are two-party contracts that may be subject to contractual restrictions on transferability and termination and because they may have terms of greater than seven days, swap agreements may be considered to be illiquid. If a swap is not liquid, it may not be possible to initiate a transaction or liquidate a position at an advantageous time or price, which may result in significant losses.

Moreover, a Fund bears the risk of loss of the amount expected to be received under a swap agreement in the event of the default or bankruptcy of a swap agreement counterparty. When a counterparty’s obligations are

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not fully secured by collateral, then the Fund is essentially an unsecured creditor of the counterparty. If the counterparty defaults, the Fund will have contractual remedies, but there is no assurance that a counterparty will be able to meet its obligations pursuant to such contracts or that, in the event of default, the Fund will succeed in enforcing contractual remedies. Counterparty risk still exists even if a counterparty’s obligations are secured by collateral because the Fund’s interest in collateral may not be perfected or additional collateral may not be promptly posted as required. Counterparty risk also may be more pronounced if a counterparty’s obligations exceed the amount of collateral held by the Fund (if any), the Fund is unable to exercise its interest in collateral upon default by the counterparty, or the termination value of the instrument varies significantly from the marked-to-market value of the instrument.

Counterparty risk with respect to derivatives will be affected by new rules and regulations affecting the derivatives market. Some derivatives transactions are required to be centrally cleared, and a party to a cleared derivatives transaction is subject to the credit risk of the clearing house and the clearing member through which it holds its cleared position, rather than the credit risk of its original counterparty to the derivative transaction. Credit risk of market participants with respect to derivatives that are centrally cleared is concentrated in a few clearing houses, and it is not clear how an insolvency proceeding of a clearing house would be conducted and what impact an insolvency of a clearing house would have on the financial system. A clearing member is obligated by contract and by applicable regulation to segregate all funds received from customers with respect to cleared derivatives transactions from the clearing member’s proprietary assets. However, all funds and other property received by a clearing broker from its customers are generally held by the clearing broker on a commingled basis in an omnibus account, and the clearing member may invest those funds in certain instruments permitted under the applicable regulations. The assets of a Fund might not be fully protected in the event of the bankruptcy of a Fund’s clearing member, because the Fund would be limited to recovering only a pro rata share of all available funds segregated on behalf of the clearing broker’s customers for a relevant account class. Also, the clearing member is required to transfer to the clearing organization the amount of margin required by the clearing organization for cleared derivatives, which amounts are generally held in an omnibus account at the clearing organization for all customers of the clearing member. Regulations promulgated by the CFTC require that the clearing member notify the clearing house of the amount of initial margin provided by the clearing member to the clearing organization that is attributable to each customer. However, if the clearing member does not provide accurate reporting, the Funds are subject to the risk that a clearing organization will use a Fund’s assets held in an omnibus account at the clearing organization to satisfy payment obligations of a defaulting customer of the clearing member to the clearing organization. In addition, clearing members generally provide to the clearing organization the net amount of variation margin required for cleared swaps for all of its customers in the aggregate, rather than the gross amount of each customer. The Funds are therefore subject to the risk that a clearing organization will not make variation margin payments owed to a Fund if another customer of the clearing member has suffered a loss and is in default, and the risk that a Fund will be required to provide additional variation margin to the clearing house before the clearing house will move the Fund’s cleared derivatives transactions to another clearing member. In addition, if a clearing member does not comply with the applicable regulations or its agreement with the Funds, or in the event of fraud or misappropriation of customer assets by a clearing member, a Fund could have only an unsecured creditor claim in an insolvency of the clearing member with respect to the margin held by the clearing member.

Interest Rate Swaps. Interest rate swap agreements are often used to obtain or preserve a desired return or spread at a lower cost than through a direct investment in an instrument that yields the desired return or spread. They are financial instruments that involve the exchange of one type of interest rate cash flow for another type of interest rate cash flow on specified dates in the future. In a standard interest rate swap transaction, two parties agree to exchange their respective commitments to pay fixed or floating interest rates on a predetermined specified (notional) amount. The swap agreement’s notional amount is the predetermined basis for calculating the obligations that the swap counterparties have agreed to exchange. Under most swap agreements, the obligations of the parties are exchanged on a net basis. The two payment streams are netted out, with each party receiving or paying, as the case may be, only the net amount of the two payments. Interest rate swaps can be based on various measures of interest rates, including LIBOR, including swap rates, Treasury rates, foreign interest rates and other reference rates.

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Credit Default Swap Agreements. A Fund may enter into credit default swap agreements, which may have as reference obligations one or more securities or a basket of securities that are or are not currently held by a Fund. The protection “buyer” in a credit default contract is generally obligated to pay the protection “seller” an upfront or a periodic stream of payments over the term of the contract provided that no credit event, such as a default, on a reference obligation has occurred. If a credit event occurs, the seller generally must pay the buyer the “par value” (full notional value) of the swap in exchange for an equal face amount of deliverable obligations of the reference entity described in the swap, or the seller may be required to deliver the related net cash amount, if the swap is cash settled. A Fund may be either the buyer or seller in a credit default swap. If a Fund is a buyer and no credit event occurs, a Fund may recover nothing if the swap is held through its termination date. However, if a credit event occurs, the buyer generally may elect to receive the full notional value of the swap in exchange for an equal face amount of deliverable obligations of the reference entity whose value may have significantly decreased. As a seller, a Fund generally receives an upfront payment or a fixed rate of income throughout the term of the swap provided that there is no credit event. As the seller, a Fund would effectively add leverage to its portfolio because, in addition to its total net assets, a Fund would be subject to investment exposure on the notional amount of the swap.

Credit default swap agreements may involve greater risks than if a Fund had invested in the reference obligation directly since, in addition to risks relating to the reference obligation, credit default swaps are subject to liquidity risk, counterparty risk and credit risk. A Fund will enter into credit default swap agreements generally with counterparties that meet certain standards of creditworthiness. A buyer generally will lose its investment and recover nothing if no credit event occurs and the swap is held to its termination date. If a credit event were to occur, the value of any deliverable obligation received by the seller, coupled with the upfront or periodic payments previously received, may be less than the full notional value it pays to the buyer, resulting in a loss of value to the seller.

A Fund’s obligations under a credit default swap agreement will be accrued daily (offset against any amounts owing to the Fund). In connection with credit default swaps, the Fund generally will designate on its books and records cash or liquid securities with a value at least equal to the Fund’s maximum potential future payment obligations under the agreement. Such designation is intended to ensure that a Fund has assets available to satisfy its obligations with respect to the transaction. Such segregation or designation will not limit a Fund’s exposure to loss.

Equity Swaps. A Fund may engage in equity swaps. Equity swaps allow the parties to the swap agreement to exchange components of return on one equity investment (e.g., a basket of equity securities or an index) for a component of return on another non-equity or equity investment, including an exchange of differential rates of return. Equity swaps may be used to invest in a market without owning or taking physical custody of securities in circumstances where direct investment may be restricted for legal reasons or is otherwise impractical. Equity swaps also may be used for other purposes, such as hedging or seeking to increase total return.

Total Return Swap Agreements. Total return swap agreements are contracts in which one party agrees to make periodic payments to another party based on the change in market value of the assets underlying the contract, which may include a specified security, basket of securities or securities indices during the specified period, in return for periodic payments based on a fixed or variable interest rate or the total return from other underlying assets. Total return swap agreements may be used to obtain exposure to a security or market without owning or taking physical custody of such security or investing directly in such market. Total return swap agreements may effectively add leverage to a Fund’s portfolio because, in addition to its total net assets, a Fund would be subject to investment exposure on the notional amount of the swap.

Total return swap agreements are subject to the risk that a counterparty will default on its payment obligations to a Fund thereunder, and conversely, that a Fund will not be able to meet its obligation to the counterparty. Generally, a Fund will enter into total return swaps on a net basis (i.e., the two payment streams are netted against one another with a Fund receiving or paying, as the case may be, only the net amount of the two payments). The net amount of the excess, if any, of a Fund’s obligations over its entitlements with respect to each total return swap will be accrued on a daily basis, and an amount of cash or liquid securities having a value at

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least equal to the maximum potential future payment obligations under the agreement generally will be designated by a Fund on its books and records.

Variance, Volatility and Correlation Swap Agreements. Variance and volatility swaps are contracts that provide exposure to increases or decreases in the volatility of certain referenced assets. Correlation swaps are contracts that provide exposure to increases or decreases in the correlation between the prices of different assets or different market rates.

Commodity-Linked Swaps. Commodity-linked swaps are two-party contracts in which the parties agree to exchange the return or interest rate on one instrument for the return of a particular commodity, commodity index or commodities futures or options contract. The payment streams are calculated by reference to an agreed upon notional amount. A one-period swap contract operates in a manner similar to a forward or futures contract because there is an agreement to swap a commodity for cash at only one forward date. A Fund may engage in swap transactions that have more than one period and therefore more than one exchange of commodities. A Fund may invest in total return commodity swaps to gain exposure to the overall commodity markets. In a total return commodity swap, a Fund will receive the price appreciation of a commodity index, a portion of the index, or a single commodity in exchange for paying an agreed-upon fee. If the commodity swap is for one period, the Fund will pay a fixed fee, established at the outset of the swap. However, if the term of the commodity swap is more than one period, with interim swap payments, the Fund will pay an adjustable or floating fee. With a “floating” rate, the fee is pegged to a reference rate such as LIBOR or SOFR, and is adjusted each period. Therefore, if interest rates increase over the term of the swap contract, a Fund may be required to pay a higher fee at each swap reset date.

Cross Currency Swaps. Cross currency swaps are similar to interest rate swaps, except that they involve multiple currencies. A Fund may enter into a cross currency swap when it has exposure to one currency and desires exposure to a different currency. Typically, the interest rates that determine the cross currency swap payments are fixed, although occasionally one or both parties may pay a floating rate of interest. Unlike an interest rate swap, however, the principal amounts are exchanged at the beginning of the contract and returned at the end of the contract. In addition to paying and receiving amounts at the beginning and termination of the agreements, both sides will have to pay in full periodically based upon the currency they have borrowed. Changes in foreign exchange currency rates and changes in interest rates, as described above, may negatively affect cross currency swaps.

Contracts for Differences. Contracts for differences are swap arrangements in which the parties agree that their return (or loss) will be based on the relative performance of two different groups or baskets of securities. Often, one or both baskets will be an established securities index. A Fund’s return will be based on changes in value of theoretical long futures positions in the securities comprising one basket (with an aggregate face value equal to the notional amount of the contract for differences) and theoretical short futures positions in the securities comprising the other basket. A Fund also may use actual long and short futures positions and achieve similar market exposure by netting the payment obligations of the two contracts. A Fund typically enters into contracts for differences (and analogous futures positions) when the Investment Manager believes that the basket of securities constituting the long position will outperform the basket constituting the short position. If the short basket outperforms the long basket, a Fund will realize a loss — even in circumstances when the securities in both the long and short baskets appreciate in value.

Swaptions. A swaption is an options contract on a swap agreement. These transactions give a party the right (but not the obligation) to enter into new swap agreements or to shorten, extend, cancel or otherwise modify an existing swap agreement (which are described herein) at some designated future time on specified terms, in return for payment of the purchase price (the “premium”) of the option. A Fund may write (sell) and purchase put and call swaptions to the same extent it may make use of standard options on securities or other instruments. The writer of the contract receives the premium and bears the risk of unfavorable changes in the market value on the underlying swap agreement. Swaptions can be bundled and sold as a package. These are commonly called interest rate caps, floors and collars (which are described herein).

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Many swaps are complex and often valued subjectively. Many over-the-counter derivatives are complex and their valuation often requires modeling and judgment, which increases the risk of mispricing or incorrect valuation. The pricing models used may not produce valuations that are consistent with the values the Fund realizes when it closes or sells an over-the-counter derivative. Valuation risk is more pronounced when the Fund enters into over-the-counter derivatives with specialized terms because the market value of those derivatives in some cases is determined in part by reference to similar derivatives with more standardized terms. Incorrect valuations may result in increased cash payment requirements to counterparties, undercollateralization and/or errors in calculation of the Fund’s NAV. Title VII of the Dodd-Frank Wall Street Reform and Consumer Protection Act (the “Dodd-Frank Act”) established a framework for the regulation of OTC swap markets; the framework outlined the joint responsibility of the CFTC and the SEC in regulating swaps. The CFTC is responsible for the regulation of swaps, the SEC is responsible for the regulation of security-based swaps and they are both jointly responsible for the regulation of mixed swaps.

Risk of Potential Governmental Regulation of Derivatives

It is possible that government regulation of various types of derivative instruments, including futures and swap agreements, may limit or prevent the Funds from using such instruments as a part of their investment strategy, and could ultimately prevent the Funds from being able to achieve their investment objectives. The effects of present or future legislation and regulation in this area are not known, but the effects could be substantial and adverse. The futures markets are subject to comprehensive statutes, regulations, and margin requirements. In addition, the SEC, the CFTC and the exchanges are authorized to take extraordinary actions in the event of a market emergency, including, for example, the implementation or reduction of speculative position limits, the implementation of higher margin requirements, the establishment of daily price limits and the suspension of trading.

The regulation of swaps and futures transactions in the U.S. is a rapidly changing area of law and is subject to modification by government and judicial action. There is a possibility of future regulatory changes altering, perhaps to a material extent, the nature of an investment in a Fund or the ability of a Fund to continue to implement its investment strategies. In particular, the Dodd-Frank Act, which was signed into law in July 2010, has changed the way in which the U.S. financial system is supervised and regulated. Title VII of the Dodd-Frank Act sets forth the legislative framework for OTC derivatives, such as swaps, in which the Funds may invest. Title VII of the Dodd-Frank Act made broad changes to the OTC derivatives market, grants significant authority to the SEC and the CFTC to regulate OTC derivatives and market participants, and requires clearing of many OTC derivatives transactions.

Recent U.S. and non-U.S. legislative and regulatory reforms, including those related to the Dodd-Frank Act, have resulted in, and may in the future result in, new regulation of derivative instruments and a Fund’s use of such instruments. New regulations could, among other things, restrict the Fund’s ability to engage in derivative transactions (for example, by making certain types of derivative instruments or transactions no longer available to the Fund) and/or increase the costs of such transactions, and the Fund may as a result be unable to execute its investment strategies in a manner the Investment Manager might otherwise choose.

The U.S. government and the European Union (and some other jurisdictions) have enacted regulations and similar requirements that prescribe clearing, margin, reporting and registration requirements for participants in the derivatives market. These requirements are evolving and their ultimate impact on a Fund remains unclear, but such impact could include restricting and/or imposing significant costs or other burdens upon the Fund’s participation in derivatives transactions. Additionally, in October 2020, the SEC adopted new regulations governing the use of derivatives by registered investment companies. Once effective, Rule 18f-4 will, among other things, require funds that invest in derivative instruments beyond a specified limited amount to apply a value-at-risk-based limit to their use of certain derivative instruments and establish a comprehensive derivatives risk management program. A fund that uses derivative instruments in a limited amount will not be subject to the full requirements of Rule 18f-4. Compliance with Rule 18f-4 will not be required until August 2022. Rule 18f-4 could have an adverse impact on a Fund’s performance and ability to implement its investment strategies as it has historically.

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Additional Risk Factors in Cleared Derivatives Transactions

Under applicable rules and regulations, transactions in some types of swaps (including interest rate swaps and credit default swaps on North American and European indices) are required to be centrally cleared. In a transaction involving those swaps (“cleared derivatives”), a Fund’s counterparty is a clearing house, rather than a bank or broker. Since the Funds are not members of clearing houses and only members of a clearing house (“clearing members”) can participate directly in the clearing house, the Funds will hold cleared derivatives through accounts at clearing members. In a cleared derivatives transaction, the Funds will make payments (including margin payments) to and receive payments from a clearing house through their accounts at clearing members. Clearing members guarantee performance of their clients’ obligations to the clearing house.

In many ways, centrally cleared derivative arrangements are less favorable to mutual funds than bilateral arrangements. For example, the Funds may be required to provide greater amounts of margin for cleared derivatives positions than for bilateral derivatives transactions. Also, in contrast to a bilateral derivatives position, following a period of notice to a Fund, a clearing member generally can require termination of an existing cleared derivatives position at any time or increases in margin requirements above the margin that the clearing member required at the beginning of a transaction. Clearing houses also have broad rights to increase margin requirements for existing positions or to terminate those positions at any time. Any increase in margin requirements or termination of existing cleared derivatives positions by the clearing member or the clearing house could interfere with the ability of a Fund to pursue its investment strategy. Further, any increase in margin requirements by a clearing member could also expose a Fund to greater credit risk to its clearing member because margin for cleared derivatives transactions in excess of a clearing house’s margin requirements typically is held by the clearing member. Also, a Fund is subject to risk if it enters into a derivatives transaction that is required to be cleared (or that the Adviser expects to be cleared), and no clearing member is willing or able to clear the transaction on the Fund’s behalf. While the documentation in place between the Funds and their clearing members generally provides that the clearing members will accept for clearing all transactions submitted for clearing that are within credit limits (specified in advance) for each Fund, the Funds are still subject to the risk that no clearing member will be willing or able to clear a transaction. In those cases, the position might have to be terminated, and the Fund could lose some or all of the benefit of the position, including loss of an increase in the value of the position and/or loss of hedging protection. In addition, the documentation governing the relationship between the Funds and clearing members is developed by the clearing members and generally is less favorable to the Funds than typical bilateral derivatives documentation. For example, documentation relating to cleared derivatives generally includes a one-way indemnity by the Funds in favor of the clearing member for losses the clearing member incurs as the Funds’ clearing member and typically does not provide the Funds any remedies if the clearing member defaults or becomes insolvent. While futures contracts entail similar risks, the risks likely are more pronounced for cleared swaps due to their more limited liquidity and market history.

Some types of cleared derivatives are required to be executed on an exchange or on a swap execution facility. A swap execution facility is a trading platform where multiple market participants can execute derivatives by accepting bids and offers made by multiple other participants in the platform. While this execution requirement is designed to increase transparency and liquidity in the cleared derivatives market, trading on a swap execution facility can create additional costs and risks for the Funds. For example, swap execution facilities typically charge fees, and if a Fund executes derivatives on a swap execution facility through a broker intermediary, the intermediary may impose fees as well. Also, a Fund may indemnify a swap execution facility, or a broker intermediary who executes cleared derivatives on a swap execution facility on the Fund’s behalf, against any losses or costs that may be incurred as a result of the Fund’s transactions on the swap execution facility.

These and other new rules and regulations could, among other things, further restrict a Fund’s ability to engage in, or increase the cost to the Fund of, derivatives transactions, for example, by making some types of derivatives no longer available to the Fund, increasing margin or capital requirements, or otherwise limiting liquidity or increasing transaction costs. These regulations relatively are new and evolving, so their potential impact on the Funds and the financial system are still being determined. While the new regulations and the central clearing of some derivatives transactions are designed to reduce systemic risk (i.e., the risk that the interdependence of large derivatives dealers

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could cause a number of those dealers to suffer liquidity, solvency or other challenges simultaneously), there is no assurance that the new clearing mechanisms will achieve that result, and in the meantime, as noted above, central clearing and related requirements expose the Funds to new kinds of risks and costs.

CFTC Regulation

The Investment Manager qualifies for an exclusion from the definition of a “commodity pool operator” under the Commodity Exchange Act (CEA) and has on file a notice of exclusion under CFTC Rule 4.5 with respect to the Funds. Accordingly, the Investment Manager is not subject to registration or regulation as a commodity pool operator under the CEA with respect to the Funds. To ensure that the Investment Manager remains eligible for the exclusion, each of the Funds is limited in its ability to use certain financial instruments regulated under the CEA (“commodity interests”), including futures and options on futures and certain swaps transactions. In the event that a Fund’s investments in commodity interests are not within the thresholds set forth in the exclusion, the Investment Manager may be required to register as a “commodity pool operator” with the CFTC with respect to that Fund. The Investment Manager’s eligibility to claim the exclusion with respect to a Fund will be based upon, among other things, the level and scope of a Fund’s investments in commodity interests, the purposes of such investments and the manner in which the Fund holds out its use of commodity interests. Each Fund’s ability to invest in commodity interests (including, but not limited to, futures and swaps on broad-based securities indexes and interest rates) is limited by the Investment Manager’s intention to operate the Fund in a manner that would permit the Investment Manager to continue to claim the exclusion under CFTC Rule 4.5, which may adversely affect the Fund’s total return. In the event the Investment Manager becomes unable to rely on the exclusion in Rule 4.5 and is required to register with the CFTC as a commodity pool operator with respect to a Fund, the Fund’s expenses may increase, adversely affecting that Fund’s total return. The Columbia Acorn Funds do not expect to have significant investments, if any, in commodity interests.

Dollar Rolls

Dollar rolls involve selling securities (e.g., mortgage-backed securities or U.S. Treasury securities) and simultaneously entering into a commitment to purchase those or similar securities on a specified future date and price from the same party. Mortgage dollar rolls and U.S. Treasury rolls are types of dollar rolls. A Fund foregoes principal and interest paid on the securities during the “roll” period. A Fund or Portfolio Fund is compensated by the difference between the current sales price and the lower forward price for the future purchase of the securities as well as the interest earned on the cash proceeds of the initial sale. The investor also could be compensated through the receipt of fee income equivalent to a lower forward price.

Although one or more of the other risks described in this SAI may also apply, the risks typically associated with mortgage dollar rolls include: Counterparty Risk, Credit Risk and Interest Rate Risk. See Information Regarding Risks.

Exchange-traded notes (ETNs)

ETNs are instruments that combine aspects of bonds and exchange-traded funds (ETFs) and are designed to provide investors with access to the returns, less investor fees and expenses, of various market benchmarks or strategies to which they are usually linked. When an investor buys an ETN, the issuer, typically an underwriting bank, promises to pay upon maturity the amount reflected in the benchmark or strategy (minus fees and expenses). Some ETNs make periodic coupon payments. Like ETFs, ETNs are traded on an exchange, but ETNs have additional risks compared to ETFs, including the risk that if the credit of the ETN issuer becomes suspect, the investment might lose some or all of its value. Though linked to the performance, for example, of a market benchmark, ETNs are not equities or index funds, but they do share several characteristics. Similar to equities, ETNs are traded on an exchange and can be sold short. Similar to index funds, ETNs may be linked to the return of a benchmark or strategy, but ETNs do not have an ownership interest in the instruments underlying the benchmark or strategy the ETN is tracking.

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Although one or more of the other risks described in this SAI may also apply, the risks typically associated with exchange-traded notes include: Counterparty Risk, Credit Risk and Market Risk. See Information Regarding Risks.

Foreign Currency Transactions

Because investments in foreign securities usually involve currencies of foreign countries and because a Fund may hold cash and cash equivalent investments in foreign currencies, the value of a Fund’s assets as measured in U.S. dollars may be affected favorably or unfavorably by changes in currency exchange rates and exchange control regulations. Also, a Fund may incur costs in connection with conversions between various currencies. Currency exchange rates may fluctuate significantly over short periods of time, causing a Fund’s NAV to fluctuate. Currency exchange rates are generally determined by the forces of supply and demand in the foreign exchange markets, actual or anticipated changes in interest rates, and other complex factors. Currency exchange rates also can be affected by the intervention of U.S. or foreign governments or central banks, or the failure to intervene, or by currency controls or political developments.

Spot Rates and Derivative Instruments. A Fund may conduct its foreign currency exchange transactions either at the spot (cash) rate prevailing in the foreign currency exchange market or by entering into forward foreign currency exchange contracts (forward contracts). (See Permissible Fund Investments — Derivatives.) These contracts are traded in the interbank market conducted directly between currency traders (usually large commercial banks) and their customers. Because foreign currency transactions occurring in the interbank market might involve substantially larger amounts than those involved in the use of such derivative instruments, a Fund could be disadvantaged by having to deal in the odd lot market for the underlying foreign currencies at prices that are less favorable than for round lots.

A Fund may enter into forward contracts for a variety of reasons, including for risk management (hedging) or for investment purposes.

When a Fund enters into a contract for the purchase or sale of a security denominated in a foreign currency or has been notified of a dividend or interest payment, it may desire to lock in the price of the security or the amount of the payment, usually in U.S. dollars, although it could desire to lock in the price of the security in another currency. By entering into a forward contract, a Fund would be able to protect itself against a possible loss resulting from an adverse change in the relationship between different currencies from the date the security is purchased or sold to the date on which payment is made or received or when the dividend or interest is actually received.

A Fund may enter into forward contracts when the Investment Manager believes the currency of a particular foreign country may decline in value relative to another currency. When selling currencies forward in this fashion, a Fund may seek to hedge the value of foreign securities it holds against an adverse move in exchange rates. The precise matching of forward contract amounts and the value of securities involved generally will not be possible since the future value of securities in foreign currencies more than likely will change between the date the forward contract is entered into and the date it matures. The projection of short-term currency market movements is extremely difficult and successful execution of a short-term hedging strategy is highly uncertain.

This method of protecting the value of a Fund’s securities against a decline in the value of a currency does not eliminate fluctuations in the underlying prices of the securities. It simply establishes a rate of exchange that can be achieved at some point in time. Although forward contracts can be used to minimize the risk of loss due to a decline in value of hedged currency, they will also limit any potential gain that might result should the value of such currency increase.

A Fund may also enter into forward contracts when the Investment Manager believes the currency of a particular country will increase in value relative to another currency. A Fund may buy currencies forward to gain

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exposure to a currency without incurring the additional costs of purchasing securities denominated in that currency.

For example, the combination of U.S. dollar-denominated instruments with long forward currency exchange contracts creates a position economically equivalent to a position in the foreign currency, in anticipation of an increase in the value of the foreign currency against the U.S. dollar. Conversely, the combination of U.S. dollar-denominated instruments with short forward currency exchange contracts is economically equivalent to borrowing the foreign currency for delivery at a specified date in the future, in anticipation of a decrease in the value of the foreign currency against the U.S. dollar.

Unanticipated changes in the currency exchange results could result in poorer performance for Funds that enter into these types of transactions.

A Fund generally will designate on its books and records cash or liquid securities in an amount at least equal to the maximum potential future payment obligations of the Fund related to consummating forward contracts entered into under the circumstance set forth above. If the value of the securities declines, additional cash or liquid securities will be designated on a daily basis so that the value of the cash or securities will equal the maximum amount of the Fund’s commitments on such contracts.

At maturity of a forward contract, a Fund may either deliver (if a contract to sell) or take delivery of (if a contract to buy) the foreign currency or terminate its contractual obligation by entering into an offsetting contract with the same currency trader, having the same maturity date, and covering the same amount of foreign currency.

If a Fund engages in an offsetting transaction, it will incur a gain or loss to the extent there has been movement in forward contract prices. If a Fund engages in an offsetting transaction, it may subsequently enter into a new forward contract to buy or sell the foreign currency.

Although a Fund values its assets each business day in terms of U.S. dollars, it may elect not to convert its foreign currencies into U.S. dollars on a daily basis. However, it will do so from time to time, and such conversions involve certain currency conversion costs. Although foreign exchange dealers do not charge a fee for conversion, they do realize a profit based on the difference (spread) between the prices at which they buy and sell various currencies. Thus, a dealer may offer to sell a foreign currency to a Fund at one rate, while offering a lesser rate of exchange should a Fund desire to resell that currency to the dealer.

It is possible, under certain circumstances, including entering into forward currency contracts for investment purposes, that a Fund will be required to limit or restructure its forward contract currency transactions to qualify as a “regulated investment company” under the Internal Revenue Code.

Options on Foreign Currencies. A Fund may buy put and call options and write covered call and cash-secured put options on foreign currencies for hedging purposes and to gain exposure to foreign currencies. For example, a decline in the dollar value of a foreign currency in which securities are denominated will reduce the dollar value of such securities, even if their value in the foreign currency remains constant. In order to protect against the diminutions in the value of securities, a Fund may buy put options on the foreign currency. If the value of the currency does decline, a Fund would have the right to sell the currency for a fixed amount in dollars and would thereby offset, in whole or in part, the adverse effect on its portfolio that otherwise would have resulted.

Conversely, where a change in the dollar value of a currency would increase the cost of securities a Fund plans to buy, or where a Fund would benefit from increased exposure to the currency, a Fund may buy call options on the foreign currency, giving it the right to purchase the currency for a fixed amount in dollars. The purchase of the options could offset, at least partially, the changes in exchange rates.

As in the case of other types of options, however, the benefit to a Fund derived from purchases of foreign currency options would be reduced by the amount of the premium and related transaction costs. In addition,

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where currency exchange rates do not move in the direction or to the extent anticipated, a Fund could sustain losses on transactions in foreign currency options that would require it to forego a portion or all of the benefits of advantageous changes in rates.

A Fund may write options on foreign currencies for similar purposes. For example, when a Fund anticipates a decline in the dollar value of foreign-denominated securities due to adverse fluctuations in exchange rates, it could, instead of purchasing a put option, write a call option on the relevant currency, giving the option holder the right to purchase that currency from the Fund for a fixed amount in dollars. If the expected decline occurs, the option would most likely not be exercised and the diminution in value of securities would be offset, at least partially, by the amount of the premium received.

Similarly, instead of purchasing a call option when a foreign currency is expected to appreciate, a Fund could write a put option on the relevant currency, giving the option holder the right to that currency from the Fund for a fixed amount in dollars. If rates move in the manner projected, the put option would expire unexercised and allow the Fund to hedge increased cost up to the amount of the premium.

As in the case of other types of options, however, the writing of a foreign currency option will constitute only a partial hedge up to the amount of the premium, and only if rates move in the expected direction. If this does not occur, the option may be exercised and the Fund would be required to buy or sell the underlying currency at a loss that may not be offset by the amount of the premium. Through the writing of options on foreign currencies, the Fund also may be required to forego all or a portion of the benefits that might otherwise have been obtained from favorable movements on exchange rates. An option written on foreign currencies is covered if a Fund holds currency sufficient to cover the option or has an absolute and immediate right to acquire that currency without additional cash consideration upon conversion of assets denominated in that currency or exchange of other currency held in its portfolio. An option writer could lose amounts substantially in excess of its initial investments due to the margin and collateral requirements associated with such positions.

Options on foreign currencies are traded through financial institutions acting as market-makers, although foreign currency options also are traded on certain national securities exchanges, such as the Philadelphia Stock Exchange and the Chicago Board Options Exchange, subject to SEC regulation. In an over-the-counter trading environment, many of the protections afforded to exchange participants will not be available. For example, there are no daily price fluctuation limits, and adverse market movements could therefore continue to an unlimited extent over a period of time. Although the purchaser of an option cannot lose more than the amount of the premium plus related transaction costs, this entire amount could be lost.

Foreign currency option positions entered into on a national securities exchange are cleared and guaranteed by the OCC, thereby reducing the risk of counterparty default. Further, a liquid secondary market in options traded on a national securities exchange may be more readily available than in the over-the-counter market, potentially permitting a Fund to liquidate open positions at a profit prior to exercise or expiration, or to limit losses in the event of adverse market movements.

Foreign Currency Futures and Related Options. A Fund may enter into currency futures contracts to buy or sell currencies. It also may buy put and call options and write covered call and cash-secured put options on currency futures. Currency futures contracts are similar to currency forward contracts, except that they are traded on exchanges (and have margin requirements) and are standardized as to contract size and delivery date. Most currency futures call for payment of delivery in U.S. dollars. A Fund may use currency futures for the same purposes as currency forward contracts, subject to CFTC limitations.

Currency futures and options on futures values can be expected to correlate with exchange rates, but will not reflect other factors that may affect the value of the Fund’s investments. A currency hedge, for example, should protect a Yen-denominated bond against a decline in the Yen, but will not protect a Fund against price decline if the issuer’s creditworthiness deteriorates. Because the value of a Fund’s investments denominated in foreign

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currency will change in response to many factors other than exchange rates, it may not be possible to match the amount of a forward contract to the value of a Fund’s investments denominated in that currency over time.

Although one or more of the other risks described in this SAI may also apply, the risks typically associated with foreign currency transactions include: Foreign Currency Risk, Derivatives Risk, Interest Rate Risk and Liquidity Risk. See Information Regarding Risks.

Foreign Securities

Unless otherwise stated in a Fund’s prospectus, stocks, bonds and other securities or investments are deemed to be “foreign” based primarily on the issuer’s place of organization/incorporation, but the Fund may also consider the issuer’s country of organization, domicile, its principal place of business, its primary stock exchange listing, the source of its revenue, or other factors. A Fund’s investments in foreign markets may include issuers in emerging markets, as well as frontier markets, each of which carry heightened risks as compared with investments in other more developed foreign markets. Unless otherwise stated in a Fund’s prospectus, emerging market countries are generally those either defined by World Bank-defined per capita income brackets or determined to be an emerging market based on the Investment Manager’s or a Portfolio Fund’s investment adviser’s qualitative judgments about a country’s level of economic and institutional development, among other factors. Frontier market countries generally have smaller economies and even less developed capital markets than typical emerging market countries (which themselves have increased investment risk relative to investing in more developed markets) and, as a result, the risks of investing in emerging market countries are magnified in frontier market countries. Foreign securities may be structured as fixed-, variable- or floating-rate obligations or as zero-coupon, pay-in-kind and step-coupon securities and may be privately placed or publicly offered. See Permissible Fund Investments — Variable- and Floating-Rate Obligations, Debt Obligations — Zero-Coupon, Pay-in-Kind and Step-Coupon Securities and — Private Placement and Other Restricted Securities for more information.

Due to the potential for foreign withholding taxes, MSCI publishes two versions of its indices reflecting the reinvestment of dividends using two different methodologies: gross dividends and net dividends. While both versions reflect reinvested dividends, they differ with respect to the manner in which taxes associated with dividend payments are treated. In calculating the net dividends version, MSCI incorporates reinvested dividends applying the withholding tax rate applicable to foreign non-resident institutional investors that do not benefit from double taxation treaties. The Investment Manager believes that the net dividends version of MSCI indices better reflects the returns U.S. investors might expect were they to invest directly in the component securities of an MSCI index.

There is a practice in certain foreign markets under which an issuer’s securities are blocked from trading at the custodian or sub-custodian level for a specified number of days before and, in certain instances, after a shareholder meeting where such shares are voted. This is referred to as “share blocking.” The blocking period can last up to several weeks. Share blocking may prevent a Fund from buying or selling securities during this period, because during the time shares are blocked, trades in such securities will not settle. It may be difficult or impossible to lift blocking restrictions, with the particular requirements varying widely by country. As a consequence of these restrictions, the Investment Manager, on behalf of a Fund, may abstain from voting proxies in markets that require share blocking.

Foreign securities may include depositary receipts, such as American Depositary Receipts (ADRs), European Depositary Receipts (EDRs) and Global Depositary Receipts (GDRs). ADRs are U.S. dollar-denominated receipts issued in registered form by a domestic bank or trust company that evidence ownership of underlying securities issued by a foreign issuer. EDRs are foreign currency-denominated receipts issued in Europe, typically by foreign banks or trust companies and foreign branches of domestic banks, that evidence ownership of foreign or domestic securities. GDRs are receipts structured similarly to ADRs and EDRs and are marketed globally. Depositary receipts will not necessarily be denominated in the same currency as their underlying securities. In general, ADRs, in registered form, are designed for use in the U.S. securities markets,

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and EDRs, in bearer form, are designed for use in European securities markets. GDRs are tradable both in the United States and in Europe and are designed for use throughout the world. A Fund may invest in depositary receipts through “sponsored” or “unsponsored” facilities. A sponsored facility is established jointly by the issuer of the underlying security and a depositary, whereas a depositary may establish an unsponsored facility without participation by the issuer of the deposited security. Holders of unsponsored depositary receipts generally bear all the costs of such facilities and the depositary of an unsponsored facility frequently is under no obligation to distribute interest holder communications received from the issuer of the deposited security or to pass through voting rights to the holders of such receipts in respect of the deposited securities. The issuers of unsponsored depositary receipts are not obligated to disclose material information in the United States, and, therefore, there may be limited information available regarding such issuers and/or limited correlation between available information and the market value of the depositary receipts.

Liquidity and Trading Volume Risks of Foreign Investing. A Fund that invests a significant percentage of its assets in foreign securities, including in emerging markets, may be subject to the liquidity and trading volume risks associated with international investing, including in emerging markets. Due to market conditions, including uncertainty regarding the price of a security, it may be difficult for the Fund to buy or sell foreign portfolio securities at a desirable time or price, which could result in investment losses. This risk of portfolio illiquidity is heightened with respect to small- and mid-cap securities, generally, and foreign small- and mid-cap securities in particular. The Fund may have to lower the selling price, liquidate other investments, or forego another, more appealing investment opportunity as a result of illiquidity in the markets. The Investment Manager will fair value in good faith any securities it deems to be illiquid under consistently applied procedures established by the Fund’s Board. Market conditions are always changing and vary by country and industry sector, and investing in international markets involves unique risks. Although it is difficult to accurately assess trends in trading volumes in foreign markets, because some amount of activity has migrated to alternative trading venues, a reduction in trading volumes poses challenges to the Fund. This is particularly so when a Fund focuses on small- and mid-cap companies that usually have lower trading volumes and often takes sizeable positions in portfolio companies. As a result of lower trading volumes, it may take longer to buy or sell the securities of such companies, which can exacerbate the Fund’s exposure to volatile markets. The Fund may also be limited in its ability to execute favorable trades in foreign portfolio securities in response to changes in company prices and fundamentals. If the Fund is forced to sell securities to meet redemption requests or other cash needs, or in the case of an event affecting liquidity in a particular market or markets, it may be forced to dispose of those securities under disadvantageous circumstances and at a loss. As a Fund grows in size, these considerations take on increasing significance and may adversely impact performance.

Although one or more of the other risks described in this SAI may also apply, the risks typically associated with foreign securities include: Emerging Markets Securities Risk, Foreign Currency Risk, Foreign Securities Risk, Frontier Market Risk, Geographic Focus Risk, Issuer Risk and Market Risk. See Information Regarding Risks.

Guaranteed Investment Contracts (Funding Agreements)

Guaranteed investment contracts, or funding agreements, are short-term, privately placed debt instruments issued by insurance companies. Pursuant to such contracts, a Fund may make cash contributions to a deposit fund of the insurance company’s general account. The insurance company then credits to a Fund payments at negotiated, floating or fixed interest rates. A Fund will purchase guaranteed investment contracts only from issuers that, at the time of purchase, meet certain credit and quality standards.

In general, guaranteed investment contracts are not assignable or transferable without the permission of the issuing insurance companies, and an active secondary market does not exist for these investments. In addition, the issuer may not be able to pay the principal amount to a Fund on seven days notice or less, at which time the investment may be considered illiquid. See Permissible Fund Investments — Illiquid Investments.

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Although one or more of the other risks described in this SAI may also apply, the risks typically associated with guaranteed investment contracts (funding agreements) include: Credit Risk and Liquidity Risk. See Information Regarding Risks.

High Yield Securities

High yield or low and below investment grade securities (below investment grade securities are also known as “junk bonds”) are debt securities with the lowest investment grade rating (e.g., BBB by S&P and Fitch or Baa by Moody’s), that are below investment grade (e.g., lower than BBB by S&P and Fitch or Baa by Moody’s) or that are unrated but determined by the Investment Manager to be of comparable quality. These types of securities may be issued to fund corporate transactions or restructurings, such as leveraged buyouts, mergers, acquisitions, debt reclassifications or similar events, are more speculative in nature than securities with higher ratings and tend to be more sensitive to credit risk, particularly during a downturn in the economy. These types of securities generally are issued by unseasoned companies without long track records of sales and earnings, or by companies or municipalities that have questionable credit strength. High yield securities and comparable unrated securities: (i) likely will have some quality and protective characteristics that, in the judgment of one or more NRSROs, are outweighed by large uncertainties or major risk exposures to adverse conditions; (ii) are speculative with respect to the issuer’s capacity to pay interest and repay principal in accordance with the terms of the obligation; and (iii) may have a less liquid secondary market, potentially making it difficult to value or sell such securities. Credit ratings issued by credit rating agencies are designed to evaluate the safety of principal and interest payments of rated securities. They do not, however, evaluate the market value risk of lower-quality securities and, therefore, may not fully reflect the true risks of an investment. In addition, credit rating agencies may or may not make timely changes in a rating to reflect changes in the economy or in the condition of the issuer that affect the market value of the securities. Consequently, credit ratings are used only as a preliminary indicator of investment quality. High yield securities may be structured as fixed-, variable- or floating-rate obligations or as zero-coupon, pay-in-kind and step-coupon securities and may be privately placed or publicly offered. See Permissible Fund Investments — Variable- and Floating-Rate Obligations, Debt Obligations — Zero-Coupon, Pay-in-Kind and Step-Coupon Securities and — Private Placement and Other Restricted Securities for more information.

The rates of return on these types of securities generally are higher than the rates of return available on more highly rated securities, but generally involve greater volatility of price and risk of loss of principal and income, including the possibility of default by or insolvency of the issuers of such securities. Accordingly, a Fund may be more dependent on the Investment Manager’s credit analysis with respect to these types of securities than is the case for more highly rated securities.

The market values of certain high yield securities and comparable unrated securities tend to be more sensitive to individual corporate developments and changes in economic conditions than are the market values of more highly rated securities. In addition, issuers of high yield and comparable unrated securities often are highly leveraged and may not have more traditional methods of financing available to them, so that their ability to service their debt obligations during an economic downturn or during sustained periods of rising interest rates may be impaired.

The risk of loss due to default is greater for high yield and comparable unrated securities than it is for higher rated securities because high yield securities and comparable unrated securities generally are unsecured and frequently are subordinated to more senior indebtedness. A Fund may incur additional expenses to the extent that it is required to seek recovery upon a default in the payment of principal or interest on its holdings of such securities. The existence of limited markets for lower-rated debt securities may diminish a Fund’s ability to: (i) obtain accurate market quotations for purposes of valuing such securities and calculating portfolio NAV; and (ii) sell the securities at fair market value either to meet redemption requests or to respond to changes in the economy or in financial markets.

Many lower-rated securities are not registered for offer and sale to the public under the 1933 Act. Investments in these restricted securities may be determined to be liquid (able to be sold or disposed of in current

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market conditions in seven days or less without the sales or dispositions significantly changing the market value of the investment) pursuant to the Funds’ liquidity risk management program. Restricted securities may be less liquid than other lower-rated securities, potentially making it difficult to value or sell such securities. For information regarding certain limits on the Funds’ investments in illiquid investments, restricted securities and other securities for which there is no ready market, see Fundamental and Non-Fundamental Investment Policies.

Although one or more of the other risks described in this SAI may also apply, the risks typically associated with high yield securities include: Credit Risk, Interest Rate Risk, High Yield Securities Risk and Prepayment and Extension Risk. See Information Regarding Risks.

Inflation-Protected Securities

Inflation is a general rise in prices of goods and services. Inflation erodes the purchasing power of an investor’s assets. For example, if an investment provides a total return of 7% in a given year and inflation is 3% during that period, the inflation-adjusted, or real, return is 4%. Inflation-protected securities are debt securities whose principal and/or interest payments are adjusted for inflation, unlike debt securities that make fixed principal and interest payments. One type of inflation-protected debt security is issued by the U.S. Treasury. The principal of these securities is adjusted for inflation as indicated by the Consumer Price Index (CPI) for urban consumers and interest is paid on the adjusted amount. The CPI is a measurement of changes in the cost of living, made up of components such as housing, food, transportation and energy.

If the CPI falls, the principal value of inflation-protected securities will be adjusted downward, and consequently the interest payable on these securities (calculated with respect to a smaller principal amount) will be reduced. Conversely, if the CPI rises, the principal value of inflation-protected securities will be adjusted upward, and consequently the interest payable on these securities will be increased. Repayment of the original bond principal upon maturity is guaranteed in the case of U.S. Treasury inflation-protected securities, even during a period of deflation. However, the current market value of the inflation-protected securities is not guaranteed and will fluctuate. Other inflation-indexed securities include inflation-related bonds, which may or may not provide a similar guarantee. If a guarantee of principal is not provided, the adjusted principal value of the bond repaid at maturity may be less than the original principal.

Other issuers of inflation-protected debt securities include other U.S. government agencies or instrumentalities, corporations and foreign governments. There can be no assurance that the CPI or any foreign inflation index will accurately measure the real rate of inflation in the prices of goods and services. Moreover, there can be no assurance that the rate of inflation in a foreign country will be correlated to the rate of inflation in the United States. If interest rates rise due to reasons other than inflation (for example, due to changes in currency exchange rates), investors in these securities may not be protected to the extent that the increase is not reflected in the bond’s inflation measure.

Any increase in principal for an inflation-protected security resulting from inflation adjustments is considered by IRS regulations to be taxable income in the year it occurs. For direct holders of an inflation-protected security, this means that taxes must be paid on principal adjustments even though these amounts are not received until the bond matures. Similarly, a fund treated as a regulated investment company (RIC) under the Code that holds these securities distributes both interest income and the income attributable to principal adjustments in the form of cash or reinvested shares, which are taxable to shareholders.

Although one or more of the other risks described in this SAI may also apply, the risks typically associated with inflation-protected securities include: Inflation-Protected Securities Risk, Interest Rate Risk and Market Risk. In addition, inflation-protected securities issued by non-U.S. government agencies or instrumentalities are subject to Credit Risk. See Information Regarding Risks.

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Illiquid Investments

An illiquid investment is any investment that a Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without the sale or disposition significantly changing the market value of the investment. Some securities, such as those not registered under U.S. securities laws, cannot be sold in public transactions. Some securities are deemed to be illiquid because they are subject to contractual or legal restrictions on resale. Subject to its investment policies, a Fund may invest in illiquid investments and may invest in certain restricted securities that are deemed to be illiquid investments at the time of purchase.

Although one or more of the other risks described in this SAI may also apply, the risks typically associated with illiquid investments include: Liquidity Risk. See Information Regarding Risks.

Initial Public Offerings

A Fund may invest in initial public offerings (IPOs) of common stock or other primary or secondary syndicated offerings of equity or debt securities issued by a corporate issuer. A purchase of IPO securities often involves higher transaction costs than those associated with the purchase of securities already traded on exchanges or markets. A Fund may hold IPO securities for a period of time, or may sell them soon after the purchase. Investments in IPOs could have a magnified impact — either positive or negative — on a Fund’s performance while the Fund’s assets are relatively small. The impact of an IPO on a Fund’s performance may tend to diminish as the Fund’s assets grow. In circumstances when investments in IPOs make a significant contribution to a Fund’s performance, there can be no assurance that similar contributions from IPOs will continue in the future.

Although one or more risks described in this SAI may also apply, the risks typically associated with IPOs include: Initial Public Offering (IPO) Risk, Issuer Risk, Liquidity Risk, Market Risk and Small Company Securities Risk. See Information Regarding Risks.

Inverse Floaters

See Permissible Fund Investments — Derivatives — Indexed or Linked Securities (Structured Products).

Investments in Other Investment Companies (Including ETFs)

Investing in other investment companies may be a means by which a Fund seeks to achieve its investment objective. A Fund may invest in securities issued by other investment companies within the limits prescribed by the 1940 Act, the rules and regulations thereunder and any exemptive relief currently or in the future available to a Fund. These securities include shares of other affiliated or unaffiliated open-end investment companies (i.e., mutual funds), closed-end funds, exchange-traded funds (ETFs), UCITS funds (pooled investment vehicles established in accordance with the Undertaking for Collective Investment in Transferable Securities) and business development companies.

The 1940 Act, in summary, provides that a fund generally may not: (i) purchase more than 3% of the outstanding voting stock of another investment company; (ii) purchase securities issued by another investment company in an amount representing more than 5% of the investing fund’s total assets; or (iii) purchase securities issued by investment companies that in the aggregate represent more than 10% of the acquiring fund’s total assets (the “Statutory Limits”). Affiliated funds-of-funds (i.e., those funds that invest in other funds within the same fund family), with respect to investments in such affiliated underlying funds, are not subject to the Statutory Limits and, therefore, may invest in affiliated underlying funds without restriction. Currently, a fund-of-funds may also invest its assets in unaffiliated funds, but generally may not purchase more than 3% of the outstanding voting stock of any one unaffiliated fund. Additionally, certain exceptions to these limitations apply to investments in money market open-end funds. If shares of the Fund are purchased by an affiliated fund beyond the Statutory Limits in reliance on Section 12(d)(1)(G) of the 1940 Act, for so long as shares of the Fund are held by such other affiliated fund beyond the Statutory Limits, the Fund will not purchase securities of a registered

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open-end investment company or registered unit investment trust in reliance on Section 12(d)(1)(F) or Section 12(d)(1)(G) of the 1940 Act. In October 2020, the SEC adopted certain regulatory changes and took other actions related to the ability of an investment company to invest in the securities of another investment company. These changes include, among other things, the rescission of certain SEC exemptive orders and rules permitting investments in excess of the Statutory Limits and the withdrawal of certain related SEC staff no-action letters, and the adoption of Rule 12d1-4 under the 1940 Act. Rule 12d1-4, which became effective on January 19, 2021, permits the Funds to invest in other investment companies beyond the Statutory Limits, subject to certain conditions. After January 19, 2022, if shares of a Fund are purchased by another fund beyond the Statutory Limits and the Fund purchases shares of another investment company, the Fund will not be able to make new investments in other funds, including private funds exempt from the definition of “investment company” under the 1940 Act by Sections 3(c)(1) or 3(c)(7) thereof, if, as a result of such investment, more than 10% of the Fund’s assets would be invested in other funds. In addition, after January 19, 2022, an affiliated fund-of-funds’ investment in unaffiliated funds may be made only pursuant to Rule 12d1-4.

Other investment companies may include ETFs, which are shares of publicly traded unit investment trusts, open-end funds or depositary receipts that may be passively managed (e.g. they seek to track the performance of specific indexes or companies in related industries), or they may be actively managed. The SEC has granted orders for exemptive relief to certain ETFs that permit investments in those ETFs by certain other registered investment companies in excess of these limits. ETFs are listed on an exchange and trade in the secondary market on a per-share basis, which allows investors to purchase and sell ETF shares at their market price throughout the day. Certain ETFs, such as passively managed ETFs, hold portfolios of securities that are designed to replicate, as closely as possible before expenses, the price and yield of a specified market index. The performance results of these ETFs will not replicate exactly the performance of the pertinent index due to transaction and other expenses, including fees to service providers borne by ETFs. ETF shares are sold and redeemed at NAV only in large blocks called creation units. The Funds’ ability to redeem creation units may be limited by the 1940 Act, which provides that ETFs will not be obligated to redeem shares held by the Funds in an amount exceeding one percent of their total outstanding securities during any period of less than 30 days.

Although a Fund may derive certain advantages from being able to invest in shares of other investment companies, such as to be fully invested, there may be potential disadvantages. Investing in other investment companies may result in higher fees and expenses for a Fund and its shareholders. A shareholder may be charged fees not only on Fund shares held directly but also on the investment company shares that a Fund purchases. Because these investment companies may invest in other securities, they are also subject to the risks associated with a variety of investment instruments as described in this SAI.

Under the 1940 Act and rules and regulations thereunder, a Fund may purchase shares of affiliated funds, subject to certain conditions. Investing in affiliated funds presents certain actual or potential conflicts of interest. For more information about such actual and potential conflicts of interest, see Investment Advisory and Other Services—Other Roles and Relationships of Ameriprise Financial and its Affiliates—Certain Conflicts of Interest.

Although one or more of the other risks described in this SAI may also apply, the risks typically associated with investing in the securities of other investment companies include: Exchange-Traded Fund (ETF) Risk, Investing in Other Funds Risk, Issuer Risk and Market Risk. See Information Regarding Risks.

Listed Private Equity Funds

A Portfolio Fund may invest directly in listed private equity funds, which may include, among others, business development companies, investment holding companies, publicly traded limited partnership interests (common units), publicly traded venture capital funds, publicly traded venture capital trusts, publicly traded private equity funds, publicly traded private equity investment trusts, publicly traded closed-end funds, publicly traded financial institutions that lend to or invest in privately held companies and any other publicly traded vehicle whose purpose is to invest in privately held companies.

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A Portfolio Fund may invest in listed private equity funds that hold investments in a wide array of businesses and industries at various stages of development, from early stage to later stage to fully mature businesses. A Portfolio Fund may invest in listed private equity funds that emphasize making equity and equity-like (preferred stock, convertible stock and warrants) investments in later stage to mature businesses, or may invest in listed private equity funds making debt investments or investments in companies at other stages of development. In addition, a Portfolio Fund may invest in the common stock of closed-end management investment companies, including business development companies that invest in securities of listed private equity companies.

Although one or more of the other risks described in this SAI may also apply, the risks typically associated with investment in listed private equity funds include: Credit Risk, Liquidity Risk, Market Risk, Sector Risk, and Valuation Risk. See Information Regarding Risks.

Money Market Instruments

Money market instruments are generally characterized by a high degree of safety of principal and are most commonly traded in units of $1 million or more. The instruments range in maturity from one to 397 days; the most common mature in three months or less. Instruments with longer maturities may be treated as money market instruments if their interest rate is adjusted to a current market rate, or if the holder has the right to demand repayment, at least annually. Active secondary markets for most of the instruments allow them to be sold prior to maturity.

Money market instruments include: (i) certificates of deposit (CDs), time deposits and bankers’ acceptances of banks or savings and loan associations having capital surplus and undivided profits (as of the date of its most recently published annual financial statements) in excess of $100 million (or the equivalent in the instance of a foreign branch of a U.S. bank) at the date of investment; (ii) funding agreements for insurance companies and other financial institutions; (iii) repurchase agreements; (iv) obligations of the United States, foreign countries and supranational entities, and each of their subdivisions, agencies and instrumentalities; (v) corporate debt securities and obligations, such as commercial paper and commercial notes; (vi) participation interests in commercial loans; (vii) variable rate demand obligations issued by municipalities and corporations and (viii) notes issued by municipalities in anticipation of tax receipts or other revenues or financings. Money market instruments may be structured as fixed-, variable- or floating-rate obligations, may be secured by a guarantee, bank letter of credit or standby liquidity facility, and may be privately placed or publicly offered. See Types of Investments — Variable- and Floating-Rate Obligations and Types of Investments — Private Placement and Other Restricted Securities for more information.

A Fund may also invest in affiliated and unaffiliated money market mutual funds, which invest primarily in money market instruments, including a money market fund established for the exclusive use of the funds in the Columbia Fund Complex and other institutional clients of Columbia Management.

With respect to money market securities, certain U.S. Government obligations are backed or insured by the U.S. Government, its agencies or its instrumentalities. Other money market securities are backed only by the claims paying ability or creditworthiness of the issuer. See Types of Investments — U.S. Government and Related Obligations for more information.

Although one or more of the other risks described in this SAI may also apply, the risks typically associated with money market instruments include: Credit Risk, Inflation Risk, Interest Rate Risk, Issuer Risk and Money Market Fund Risk. See Information Regarding Risks.

Mortgage-Backed Securities

Mortgage-backed securities are a type of asset-backed security that represent interests in, or debt instruments backed by, pools of underlying mortgages. In some cases, these underlying mortgages may be

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insured or guaranteed by the U.S. Government or its agencies. Mortgage-backed securities entitle the security holders to receive distributions that are tied to the payments made on the underlying mortgage collateral (less fees paid to the originator, servicer, or other parties, and fees paid for credit enhancement), so that the payments made on the underlying mortgage collateral effectively pass through to such security holders. Mortgage-backed securities are created when mortgage originators (or mortgage loan sellers who have purchased mortgage loans from mortgage loan originators) sell the underlying mortgages to a special purpose entity in a process called a securitization. The special purpose entity issues securities that are backed by the payments on the underlying mortgage loans, and have a minimum denomination and specific term. A decline or flattening of housing values may cause delinquencies in mortgages (especially sub-prime or non-prime mortgages) underlying mortgage-backed securities and thereby adversely affect the ability of the mortgage-backed securities issuer to make principal and/or interest payments to mortgage-backed securities holders. Mortgage-backed securities may be structured as fixed-, variable- or floating-rate obligations or as zero-coupon, pay-in-kind and step-coupon securities and may be privately placed or publicly offered. See Permissible Fund Investments — Variable- and Floating-Rate Obligations, Debt Obligations — Zero-Coupon, Pay-in-Kind and Step-Coupon Securities and — Private Placement and Other Restricted Securities for more information.

Mortgage-backed securities may be issued or guaranteed by the Government National Mortgage Association (GNMA, also known as Ginnie Mae), the Federal National Mortgage Association (FNMA, also known as Fannie Mae), or the Federal Home Loan Mortgage Corporation (FHLMC, also known as Freddie Mac), but also may be issued or guaranteed by other issuers, including private companies. GNMA is a government-owned corporation that is an agency of the U.S. Department of Housing and Urban Development. It guarantees, with the full faith and credit of the United States, full and timely payment of all monthly principal and interest on its mortgage-backed securities. Until recently, FNMA and FHLMC were government-sponsored corporations owned entirely by private stockholders. Both issue mortgage-related securities that contain guarantees as to timely payment of interest and principal but that are not backed by the full faith and credit of the U.S. Government. The value of the companies’ securities fell sharply in 2008 due to concerns that the firms did not have sufficient capital to offset losses. The U.S. Treasury has historically had the authority to purchase obligations of Fannie Mae and Freddie Mac. In addition, in 2008, due to capitalization concerns, Congress provided the U.S. Treasury with additional authority to lend Fannie Mae and Freddie Mac emergency funds and to purchase the companies’ stock, as described below. In September 2008, the U.S. Treasury and the Federal Housing Finance Agency (FHFA) announced that Fannie Mae and Freddie Mac had been placed in conservatorship.

In the past, Fannie Mae and Freddie Mac have received significant capital support through U.S. Treasury preferred stock purchases and Federal Reserve purchases of their mortgage backed securities. There can be no assurance that these or other agencies of the government will provide such support in the future. The future status of Fannie Mae or Freddie Mac could be impacted by, among other things, the actions taken and restrictions placed on Fannie Mae or Freddie Mac by the FHFA in its role as conservator, the restrictions placed on Fannie Mae’s or Freddie Mac’s operations and activities under the senior stock purchase agreements, market responses to developments at Fannie Mae or Freddie Mac, and future legislative and regulatory action that alters the operations, ownership structure and/or mission of Fannie Mae or Freddie Mac, each of which may, in turn, impact the value of, and cash flows on, any securities guaranteed by Fannie Mae and Freddie Mac.

The FHFA recently announced plans to consider taking Fannie Mae and Freddie Mac out of conservatorship. Should Fannie Mae and Freddie Mac be taken out of conservatorship, it is unclear whether the U.S. Treasury would continue to enforce its rights or perform its obligations under the senior stock purchase agreements. It is also unclear how the capital structure of Fannie Mae and Freddie Mac would be constructed post-conservatorship, and what effects, if any, the privatization of the enterprises would have on their creditworthiness and guarantees of certain mortgage-backed securities. Accordingly, should the FHFA take Fannie Mae and Freddie Mac out of conservatorship, there could be an adverse impact on the value of securities guaranteed by Fannie Mae and Freddie Mac, which could cause a Fund’s shares to lose value.

Stripped mortgage-backed securities are a type of mortgage-backed security that receives differing proportions of the interest and principal payments from the underlying assets. Generally, there are two classes of

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stripped mortgage-backed securities: Interest Only (IO) and Principal Only (PO). IOs entitle the holder to receive distributions consisting of all or a portion of the interest on the underlying pool of mortgage loans or mortgage-backed securities. POs entitle the holder to receive distributions consisting of all or a portion of the principal of the underlying pool of mortgage loans or mortgage-backed securities. See Permissible Fund Investments — Debt Obligations — Stripped Securities for more information.

Collateralized mortgage obligations (CMOs) are hybrid mortgage-related instruments issued by special-purpose entities secured by pools of mortgage loans or other mortgage-related securities, such as mortgage pass-through securities or stripped mortgage backed securities. CMOs may be structured into multiple classes, often referred to as “tranches,” with each class bearing a different stated maturity and entitled to a different schedule for payments of principal and interest, including prepayments. Principal prepayments on collateral underlying a CMO may cause it to be retired substantially earlier than its stated maturity or final distribution dates, resulting in a loss of all or part of the premium if any has been paid. The yield characteristics of mortgage-backed securities differ from those of other debt securities. Among the differences are that interest and principal payments are made more frequently on mortgage-backed securities, usually monthly, and principal may be repaid at any time. These factors may reduce the expected yield. Interest is paid or accrues on all classes of the CMOs on a periodic basis. The principal and interest payments on the underlying mortgage assets may be allocated among the various classes of CMOs in several ways. Typically, payments of principal, including any prepayments, on the underlying mortgage assets are applied to the classes in the order of their respective stated maturities or final distribution dates, so that no payment of principal is made on CMOs of a class until all CMOs of other classes having earlier stated maturities or final distribution dates have been paid in full.

Commercial mortgage-backed securities (CMBS) are a specific type of mortgage-backed security collateralized by a pool of mortgages on commercial real estate.

CMO residuals are mortgage securities issued by agencies or instrumentalities of the U.S. Government or by private originators of, or investors in, mortgage loans, including savings and loan associations, homebuilders, mortgage banks, commercial banks, investment banks and special purpose entities of the foregoing. The cash flow generated by the mortgage assets underlying a series of CMOs is applied first to make required payments of principal and interest on the CMOs and second to pay the related administrative expenses and any management fee of the issuer. The residual in a CMO structure generally represents the interest in any excess cash flow remaining after making the foregoing payments. Each payment of such excess cash flow to a holder of the related CMO residual represents income and/or a return of capital. The amount of residual cash flow resulting from a CMO will depend on, among other things, the characteristics of the mortgage assets, the coupon rate of each class of CMO, prevailing interest rates, the amount of administrative expenses and the pre-payment experience on the mortgage assets. In particular, the yield to maturity on CMO residuals is extremely sensitive to pre-payments on the related underlying mortgage assets, in the same manner as an interest-only (IO) class of stripped mortgage-backed securities. In addition, if a series of a CMO includes a class that bears interest at an adjustable rate, the yield to maturity on the related CMO residual will also be extremely sensitive to changes in the level of the index upon which interest rate adjustments are based. As described below with respect to stripped mortgage-backed securities, in certain circumstances an ETF may fail to recoup fully its initial investment in a CMO residual. CMO residuals are generally purchased and sold by institutional investors through several investment banking firms acting as brokers or dealers. Transactions in CMO residuals are generally completed only after careful review of the characteristics of the securities in question. In addition, CMO residuals may or, pursuant to an exemption therefrom, may not have been registered under the 1933 Act. CMO residuals, whether or not registered under the 1933 Act, may be subject to certain restrictions on transferability, and may be deemed “illiquid” and subject to a Fund’s or a Portfolio Fund’s limitations on investment in illiquid investments.

Mortgage pass-through securities are interests in pools of mortgage-related securities that differ from other forms of debt securities, which normally provide for periodic payment of interest in fixed amounts with principal payments at maturity or specified call dates. Instead, these securities provide a monthly payment which consists of both interest and principal payments. In effect, these payments are a “pass-through” of the monthly payments made

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by the individual borrowers on their residential or commercial mortgage loans, net of any fees paid to the issuer or guarantor of such securities. Additional payments are caused by repayments of principal resulting from the sale of the underlying property, refinancing or foreclosure, net of fees or costs which may be incurred. Some mortgage-related securities (such as securities issued by the GNMA) are described as “modified pass-through.” These securities entitle the holder to receive all interest and principal payments owed on the mortgage pool, net of certain fees, at the scheduled payment dates regardless of whether or not the mortgagor actually makes the payment.

REMICs are entities that own mortgages and elect REMIC status under the Code and, like CMOs, issue debt obligations collateralized by underlying mortgage assets that have characteristics similar to those issued by CMOs.

Although one or more of the other risks described in this SAI may also apply, the risks typically associated with mortgage- and asset-backed securities include: Credit Risk, Interest Rate Risk, Issuer Risk, Liquidity Risk, Mortgage-Backed and Other Asset-Backed Securities Risk, Prepayment and Extension Risk and Reinvestment Risk. See Information Regarding Risks.

Municipal Securities

Municipal securities include debt obligations issued by governmental entities, including states, political subdivisions, agencies, instrumentalities, and authorities, as well as U.S. territories, commonwealths and possessions (such as Guam, Puerto Rico and the U.S. Virgin Islands) and their political subdivisions, agencies, instrumentalities and authorities, to obtain funds for various public purposes, including the construction of a wide range of public facilities, the refunding of outstanding obligations, the payment of general operating expenses, and the extension of loans to public institutions and facilities.

Municipal securities may include municipal bonds, municipal notes and municipal leases, which are described below. Municipal bonds are debt obligations of a governmental entity that obligate the municipality to pay the holder a specified sum of money at specified intervals and to repay the principal amount of the loan at maturity. Municipal securities can be classified into two principal categories, including “general obligation” bonds and other securities and “revenue” bonds and other securities. General obligation bonds are secured by the issuer’s full faith, credit and taxing power for the payment of principal and interest. Revenue securities are payable only from the revenues derived from a particular facility or class of facilities or, in some cases, from the proceeds of a special excise tax or other specific revenue source, such as the user of the facility being financed. Municipal securities also may include “moral obligation” securities, which normally are issued by special purpose public authorities. If the issuer of moral obligation securities is unable to meet its debt service obligations from current revenues, it may draw on a reserve fund, the restoration of which is a moral commitment but not a legal obligation of the governmental entity that created the special purpose public authority. Municipal securities may be structured as fixed-, variable- or floating-rate obligations or as zero-coupon, pay-in-kind and step-coupon securities and may be privately placed or publicly offered. See Permissible Fund Investments — Variable- and Floating-Rate Obligations, Permissible Fund Investments, Debt Obligations — Zero-Coupon, Pay-in-Kind and Step-Coupon Securities and — Private Placement and Other Restricted Securities for more information.

Municipal notes may be issued by governmental entities and other tax-exempt issuers in order to finance short-term cash needs or, occasionally, to finance construction. Most municipal notes are general obligations of the issuing entity payable from taxes or designated revenues expected to be received within the relevant fiscal period. Municipal notes generally have maturities of one year or less. Municipal notes can be subdivided into two sub-categories: (i) municipal commercial paper and (ii) municipal demand obligations.

Municipal commercial paper typically consists of very short-term unsecured negotiable promissory notes that are sold, for example, to meet seasonal working capital or interim construction financing needs of a governmental entity or agency. While these obligations are intended to be paid from general revenues or refinanced with long-term debt, they frequently are backed by letters of credit, lending agreements, note repurchase agreements or other credit facility agreements offered by banks or institutions.

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Municipal demand obligations can be subdivided into two general types: variable rate demand notes and master demand obligations. Variable rate demand notes are tax-exempt municipal obligations or participation interests that provide for a periodic adjustment in the interest rate paid on the notes. They permit the holder to demand payment of the notes, or to demand purchase of the notes at a purchase price equal to the unpaid principal balance, plus accrued interest either directly by the issuer or by drawing on a bank letter of credit or guaranty issued with respect to such note. The issuer of the municipal obligation may have a corresponding right to prepay at its discretion the outstanding principal of the note plus accrued interest upon notice comparable to that required for the holder to demand payment. The variable rate demand notes in which a Fund or Portfolio Fund may invest are payable, or are subject to purchase, on demand usually on notice of seven calendar days or less. The terms of the notes generally provide that interest rates are adjustable at intervals ranging from daily to six months.

Master demand obligations are tax-exempt municipal obligations that provide for a periodic adjustment in the interest rate paid and permit daily changes in the amount borrowed. The interest on such obligations is, in the opinion of counsel for the borrower, excluded from gross income for federal income tax purposes (but not necessarily for alternative minimum tax purposes). Although there is no secondary market for master demand obligations, such obligations are considered by a Fund or Portfolio Fund to be liquid because they are payable upon demand.

Municipal lease obligations are participations in privately arranged loans to state or local government borrowers and may take the form of a lease, an installment purchase, or a conditional sales contract. They are issued by state and local governments and authorities to acquire land, equipment, and facilities. An investor may purchase these obligations directly, or it may purchase participation interests in such obligations. In general, municipal lease obligations are unrated, in which case they will be determined by the Investment Manager or a Portfolio Fund’s investment adviser to be of comparable quality at the time of purchase to rated instruments that may be acquired by a Fund or Portfolio Fund. Frequently, privately arranged loans have variable interest rates and may be backed by a bank letter of credit. In other cases, they may be unsecured or may be secured by assets not easily liquidated. Moreover, such loans in most cases are not backed by the taxing authority of the issuers and may have limited marketability or may be marketable only by virtue of a provision requiring repayment following demand by the lender.

Municipal leases may be subject to greater risks than general obligation or revenue bonds. State constitutions and statutes set forth requirements that states or municipalities must meet in order to issue municipal obligations. Municipal leases may contain a covenant by the state or municipality to budget for and make payments due under the obligation. Certain municipal leases may, however, provide that the issuer is not obligated to make payments on the obligation in future years unless funds have been appropriated for this purpose each year.

Although lease obligations do not constitute general obligations of the municipal issuer to which the government’s taxing power is pledged, a lease obligation ordinarily is backed by the government’s covenant to budget for, appropriate, and make the payments due under the lease obligation. However, certain lease obligations contain “non-appropriation” clauses that provide that the government has no obligation to make lease or installment purchase payments in future years unless money is appropriated for such purpose on a periodic basis. In the case of a “non-appropriation” lease, a Fund’s or Portfolio Fund’s ability to recover under the lease in the event of non-appropriation or default likely will be limited to the repossession of the leased property in the event that foreclosure proves difficult.

Tender option bonds are municipal securities having relatively long maturities and bearing interest at a fixed interest rate substantially higher than prevailing short-term tax-exempt rates that is coupled with the agreement of a third party, such as a bank, broker-dealer or other financial institution, to grant the security holders the option, at periodic intervals, to tender their securities to the institution and receive the face value thereof. The financial institution receives periodic fees equal to the difference between the municipal security’s coupon rate and the rate that would cause the security to trade at face value on the date of determination.

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There are variations in the quality of municipal securities, both within a particular classification and between classifications, and the rates of return on municipal securities can depend on a variety of factors, including general money market conditions, the financial condition of the issuer, general conditions of the municipal bond market, the size of a particular offering, the maturity of the obligation, and the rating of the issue. The ratings of NRSROs represent their opinions as to the quality of municipal securities. It should be emphasized, however, that these ratings are general and are not absolute standards of quality, and municipal securities with the same maturity, interest rate, and rating may have different rates of return while municipal securities of the same maturity and interest rate with different ratings may have the same rate of return. The municipal bond market is characterized by a large number of different issuers, many having smaller sized bond issues, and a wide choice of different maturities within each issue. For these reasons, most municipal bonds do not trade on a daily basis and many trade only rarely. Because many of these bonds trade infrequently, the spread between the bid and offer may be wider and the time needed to develop a bid or an offer may be longer than for other security markets. See Appendix A for a discussion of securities ratings. (See Permissible Fund Investments — Debt Obligations.)

Standby Commitments. Standby commitments are securities under which a purchaser, usually a bank or broker-dealer, agrees to purchase, for a fee, an amount of a Fund’s or a Portfolio Fund’s municipal obligations. The amount payable by a bank or broker-dealer to purchase securities subject to a standby commitment typically will be substantially the same as the value of the underlying municipal securities. A Fund or a Portfolio Fund may pay for standby commitments either separately in cash or by paying a higher price for portfolio securities that are acquired subject to such a commitment.

Although one or more of the other risks described in this SAI may also apply, the risks typically associated with standby commitments include: Counterparty Risk, Market Risk and Municipal Securities Risk. See Information Regarding Risks.

Taxable Municipal Obligations. Interest or other investment return is subject to federal income tax for certain types of municipal obligations for a variety of reasons. These municipal obligations do not qualify for the federal income tax exemption because (a) they did not receive necessary authorization for tax-exempt treatment from state or local government authorities, (b) they exceed certain regulatory limitations on the cost of issuance for tax-exempt financing or (c) they finance public or private activities that do not qualify for the federal income tax exemption. These non-qualifying activities might include, for example, certain types of multi-family housing, certain professional and local sports facilities, refinancing of certain municipal debt, and borrowing to replenish a municipality’s underfunded pension plan.

Although one or more of the other risks described in this SAI may also apply, the risks typically associated with municipal securities include: Credit Risk, Inflation Risk, Interest Rate Risk, Market Risk and Municipal Securities Risk. See Information Regarding Risks.

Participation Interests

Participation interests (also called pass-through certificates or securities) represent an interest in a pool of debt obligations, such as municipal bonds or notes, that have been “packaged” by an intermediary, such as a bank or broker-dealer. Participation interests typically are issued by partnerships or trusts through which a Fund or Portfolio Fund receives principal and interest payments that are passed through to the holder of the participation interest from the payments made on the underlying debt obligations. The purchaser of a participation interest receives an undivided interest in the underlying debt obligations. The issuers of the underlying debt obligations make interest and principal payments to the intermediary, as an initial purchaser, which are passed through to purchasers in the secondary market, such as a Fund. Mortgage-backed securities are a common type of participation interest. Participation interests may be structured as fixed-, variable- or floating-rate obligations or as zero-coupon, pay-in-kind and step-coupon securities and may be privately placed or publicly offered. See Permissible Fund Investments — Variable- and Floating-Rate Obligations, — Debt Obligations — Zero-Coupon, Pay-in-Kind and Step-Coupon Securities and — Private Placement and Other Restricted Securities for more information.

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Loan participations also are a type of participation interest. Loans, loan participations and interests in securitized loan pools are interests in amounts owed by a corporate, governmental or other borrower to a lender or consortium of lenders (typically banks, insurance companies, investment banks, government agencies or international agencies).

Although one or more of the other risks described in this SAI may also apply, the risks typically associated with loan participations include: Confidential Information Access Risk, Credit Risk and Interest Rate Risk. See Information Regarding Risks.

Partnership Securities

A Fund may invest in securities issued by publicly traded partnerships (PTPs) or master limited partnerships (MLPs) or limited liability companies (together, referred to herein as PTPs/MLPs). These entities are limited partnerships or limited liability companies that may be publicly traded on stock exchanges or markets such as the NYSE, the NYSE Alternext US LLC (formerly the American Stock Exchange) and NASDAQ. PTPs/MLPs often own businesses or properties relating to energy, natural resources or real estate, or may be involved in the film industry or research and development activities. Generally PTPs/MLPs are operated under the supervision of one or more managing partners or members. Limited partners, unit holders, or members (such as a fund that invests in a partnership) are not involved in the day-to-day management of the company. Limited partners, unit holders, or members are allocated income and capital gains associated with the partnership project in accordance with the terms of the partnership or limited liability company agreement.

At times PTPs/MLPs may potentially offer relatively high yields compared to common stocks. Because PTPs/MLPs are generally treated as partnerships or similar limited liability “pass-through” entities for tax purposes, they do not ordinarily pay income taxes, but pass their earnings on to unit holders (except in the case of some publicly traded firms that may be taxed as corporations). For tax purposes, unit holders may initially be deemed to receive only a portion of the distributions attributed to them because certain other portions may be attributed to the repayment of initial investments and may thereby lower the cost basis of the units or shares owned by unit holders. As a result, unit holders may effectively defer taxation on the receipt of some distributions until they sell their units. These tax consequences may differ for different types of entities.

Although one or more of the other risks described in this SAI may also apply, the risks typically associated with partnership securities include: Interest Rate Risk, Issuer Risk, Liquidity Risk and Market Risk. See Information Regarding Risks.

Preferred Stock

Preferred stock represents units of ownership of a corporation that frequently have dividends that are set at a specified rate. Preferred stock has preference over common stock in the payment of dividends and the liquidation of assets. Preferred stock shares some of the characteristics of both debt and equity. Preferred stock ordinarily does not carry voting rights. Most preferred stock is cumulative; if dividends are passed (i.e., not paid for any reason), they accumulate and must be paid before common stock dividends. Participating preferred stock entitles its holders to share in profits above and beyond the declared dividend, along with common shareholders, as distinguished from nonparticipating preferred stock, which is limited to the stipulated dividend. Convertible preferred stock is exchangeable for a given number of shares of common stock and thus tends to be more volatile than nonconvertible preferred stock, which generally behaves more like a fixed income bond. Preferred stock may be privately placed or publicly offered. The price of a preferred stock is generally determined by earnings, type of products or services, projected growth rates, experience of management, liquidity, and general market conditions of the markets in which the stock trades. See Permissible Fund Investments — Private Placement and Other Restricted Securities for more information.

Auction preferred stock (APS) is a type of adjustable-rate preferred stock with a dividend determined periodically in a Dutch auction process by corporate bidders. An APS is distinguished from standard preferred

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stock because its dividends change from time to time. Shares typically are bought and sold at face values generally ranging from $100,000 to $500,000 per share. Holders of APS may not be able to sell their shares if an auction fails, such as when there are more shares of APS for sale at an auction than there are purchase bids.

Although one or more of the other risks described in this SAI may also apply, the risks typically associated with preferred stock include: Convertible Securities Risk, Issuer Risk, Liquidity Risk and Market Risk. See Information Regarding Risks.

Private Investments in Public Equity

Private Investments in public equity (or PIPEs) are equity securities purchased in a private placement that are issued by issuers who have outstanding, publicly traded equity securities of the same class. Shares issued in PIPEs are not registered with the SEC and may not be sold unless registered with the SEC or pursuant to an exemption from registration. Generally, an issuer of shares in a PIPE may agree to register the shares after a certain period from the date of the private sale. This restricted period can last many months. Until the public registration process is completed, the resale of the PIPE shares is restricted and the Fund may sell the shares after six months, with certain restrictions, if the Fund is not an affiliate of the issuer (under relevant securities law, a holder of restricted shares may sell the shares after 6 months if the holder is not affiliated to the issuer). Generally, such restrictions cause the PIPE shares to be illiquid during this time. If the issuer does not agree to register the PIPE shares, the shares will remain restricted, not be freely tradable and may only be sold pursuant to an exemption from registration. Even if the PIPE shares are registered for resale, there is no assurance that the registration will be in effect at the time the Fund elects to sell the shares. See also Types of Investments — Private Placement and Other Restricted Securities for more information.

Although one or more of the other risks described in this SAI may also apply, the risks typically associated with PIPEs include: Private Investment in Public Equity (PIPEs) Risk, Counterparty Risk, Issuer Risk, Liquidity Risk, Market Risk, and Rule 144A and Other Exempted Securities Risk.

Private Placement and Other Restricted Securities

Private placement securities are securities that have been privately placed and are not registered under the 1933 Act. They are generally eligible for sale only to certain eligible investors. Private placements often may offer attractive opportunities for investment not otherwise available on the open market. Private placement and other “restricted” securities often cannot be sold to the public without registration under the 1933 Act or the availability of an exemption from registration (such as Rules 144 or 144A), or they are “not readily marketable” because they are subject to other legal or contractual delays in or restrictions on resale. Asset-backed securities, common stock, convertible securities, corporate debt securities, foreign securities, high yield securities, money market instruments, mortgage-backed securities, municipal securities, participation interests, preferred stock and other types of equity and debt instruments may be privately placed or restricted securities.

Private placements typically may be sold only to qualified institutional buyers (or, in the case of the initial sale of certain securities, such as those issued in collateralized debt obligations or collateralized loan obligations, to accredited investors (as defined in Rule 501(a) under the 1933 Act)), or in a privately negotiated transaction or to a limited number of qualified purchasers, or in limited quantities after they have been held for a specified period of time and other conditions are met pursuant to an exemption from registration.

Although one or more of the other risks described in this SAI may also apply, the risks typically associated with private placement and other restricted securities include: Issuer Risk, Liquidity Risk, Market Risk and Confidential Information Access Risk. See Information Regarding Risks.

Real Estate Investment Trusts

Real estate investment trusts (REITs) are pooled investment vehicles that manage a portfolio of real estate or real estate related loans to earn profits for their shareholders. REITs are generally classified as equity REITs,

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mortgage REITs or a combination of equity and mortgage REITs. Equity REITs invest the majority of their assets directly in real property, such as shopping centers, nursing homes, office buildings, apartment complexes, and hotels, and derive income primarily from the collection of rents. Equity REITs can also realize capital gains by selling properties that have appreciated in value. Mortgage REITs invest the majority of their assets in real estate mortgages and derive income from the collection of interest payments. REITs can be subject to extreme volatility due to fluctuations in the demand for real estate, changes in interest rates, and adverse economic conditions.

Partnership units of real estate and other types of companies sometimes are organized as master limited partnerships in which ownership interests are publicly traded.

Similar to regulated investment companies, REITs are not taxed on income distributed to shareholders provided they comply with certain requirements under the Code. A Fund will indirectly bear its proportionate share of any expenses paid by a REIT in which it invests. REITs often do not provide complete tax information until after the calendar year-end. Consequently, because of the delay, it may be necessary for a Fund investing in REITs to request permission to extend the deadline for issuance of Forms 1099-DIV beyond January 31. In the alternative, amended Forms 1099-DIV may be sent.

Although one or more of the other risks described in this SAI may also apply, the risks typically associated with REITs include: Interest Rate Risk, Issuer Risk, Market Risk and Real Estate-Related Investment Risk. See Information Regarding Risks.

Repurchase Agreements

Repurchase agreements are agreements under which a Fund acquires a security for a relatively short period of time (usually within seven days) subject to the obligation of a seller to repurchase and a Fund to resell such security at a fixed time and price (representing the Fund’s cost plus interest). The repurchase agreement specifies the yield during the purchaser’s holding period. Repurchase agreements also may be viewed as loans made by a Fund that are collateralized by the securities subject to repurchase, which may consist of a variety of security types. A Fund typically will enter into repurchase agreements only with commercial banks, registered broker-dealers and the Fixed Income Clearing Corporation. Such transactions are monitored to ensure that the value of the underlying securities will be at least equal at all times to the total amount of the repurchase obligation, including any accrued interest.

Although one or more of the other risks described in this SAI may also apply, the risks typically associated with repurchase agreements include: Counterparty Risk, Credit Risk, Issuer Risk, Market Risk and Repurchase Agreements Risk. See Information Regarding Risks.

Reverse Repurchase Agreements

Reverse repurchase agreements are agreements under which a Fund temporarily transfers possession of a portfolio instrument to another party, such as a bank or broker-dealer, in return for cash. At the same time, the Fund agrees to repurchase the instrument at an agreed-upon time (normally within 7 days) and price which reflects an interest payment. A Fund generally retains the right to interest and principal payments on the security. Reverse repurchase agreements also may be viewed as borrowings made by a Fund.

Although one or more of the other risks described in this SAI may also apply, the risks typically associated with reverse repurchase agreements include: Credit Risk, Interest Rate Risk, Issuer Risk, Market Risk and Reverse Repurchase Agreements Risk. See Information Regarding Risks.

Sovereign Debt

Sovereign debt obligations are issued or guaranteed by foreign governments or their agencies. It may be in the form of conventional securities or other types of debt instruments such as loans or loan participations. A

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sovereign debtor’s willingness or ability to repay principal and pay interest in a timely manner may be affected by a variety of factors, including its cash flow situation, the extent of its reserves, the availability of sufficient foreign exchange on the date a payment is due, the relative size of the debt service burden to the economy as a whole, the sovereign debtor’s policy toward international lenders, and the political constraints to which a sovereign debtor may be subject. (See also Permissible Fund Investments — Foreign Securities.) In addition, there may be no legal recourse against a sovereign debtor in the event of a default.

Sovereign debt includes Brady Bonds, which are securities issued under the framework of the Brady Plan, an initiative announced by former U.S. Treasury Secretary Nicholas F. Brady in 1989 as a mechanism for debtor nations to restructure their outstanding external commercial bank indebtedness.

Although one or more of the other risks described in this SAI may also apply, the risks typically associated with sovereign debt include: Credit Risk, Emerging Markets Securities Risk, Foreign Securities Risk, Issuer Risk and Market Risk. See Information Regarding Risks.

Special Purpose Acquisition Company (SPAC)

A SPAC is typically a publicly traded company that raises investment capital via an IPO for the purpose of acquiring one or more existing companies (or interests therein) via merger, combination, acquisition or other similar transactions (each a SPAC Transaction). The shares of a SPAC are issued in “units” that typically include one share of common stock and one warrant (or partial warrant) conveying the right to purchase additional shares. Within 52 days after the closing of the IPO, the shares of common stock and the warrants comprising the units will begin to trade separately and become freely tradeable. After going public, and until a SPAC Transaction is completed, a SPAC generally invests the proceeds of its IPO (less a portion retained to cover expenses) in U.S. Government securities, money market securities and/or cash. If a SPAC does not complete a SPAC Transaction within a specified period of time after going public, the SPAC is typically dissolved, at which point the invested funds are returned to the SPAC’s shareholders (less certain permitted expenses) and any warrants issued by the SPAC expire worthless. In some cases, the Fund will forfeit its right to exercise its warrants to receive additional shares even if a SPAC Transaction occurs if the Fund holding the warrant elects to redeem its shares of common stock and not participate in the SPAC Transaction. See also Types of Investments — Common Stock, — Initial Public Offerings, and — Warrants and Rights for more information.

Although one or more of the other risks described in this SAI may also apply, the risks typically associated with SPACs include: IPO Risk, Issuer Risk, Liquidity Risk, Market Risk, Special Purpose Acquisition Companies (SPAC) Risk and Warrants and Rights Risk.

U.S. Government and Related Obligations

U.S. Government obligations include U.S. Treasury obligations and securities issued or guaranteed by various agencies of the U.S. Government or by various agencies or instrumentalities established or sponsored by the U.S. Government. U.S. Treasury obligations and securities issued or guaranteed by various agencies or instrumentalities of the U.S. Government differ in their interest rates, maturities and time of issuance, as well as with respect to whether they are guaranteed by the U.S. Government. U.S. Government and related obligations may be structured as fixed-, variable- or floating-rate obligations. See Permissible Fund Investments — Variable- and Floating-Rate Obligations for more information.

Investing in U.S. Government and related obligations is subject to certain risks. While U.S. Treasury obligations are backed by the “full faith and credit” of the U.S. Government, such securities are nonetheless subject to credit risk (i.e., the risk that the U.S. Government may be, or be perceived to be, unable or unwilling to honor its financial obligations, such as making payments). Securities issued or guaranteed by federal agencies and U.S. Government-sponsored instrumentalities may or may not be backed by the full faith and credit of the U.S. Government. These securities may be supported by the ability to borrow from the U.S. Treasury or only by the credit of the issuing agency or instrumentality and, as a result, may be subject to greater credit risk than

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securities issued or guaranteed by the U.S. Treasury. Obligations of U.S. Government agencies, authorities, instrumentalities and sponsored enterprises historically have involved limited risk of loss of principal if held to maturity. However, no assurance can be given that the U.S. Government would provide financial support to any of these entities if it is not obligated to do so by law.

Government-sponsored entities issuing securities include privately owned, publicly chartered entities created to reduce borrowing costs for certain sectors of the economy, such as farmers, homeowners, and students. They include the Federal Farm Credit Bank System, Farm Credit Financial Assistance Corporation, Fannie Mae, Freddie Mac, Student Loan Marketing Association (SLMA), and Resolution Trust Corporation (RTC). Government-sponsored entities may issue discount notes (with maturities ranging from overnight to 360 days) and bonds. On September 7, 2008, the Federal Housing Finance Agency (FHFA), an agency of the U.S. Government, placed Fannie Mae and Freddie Mac into conservatorship, a statutory process with the objective of returning the entities to normal business operations. FHFA will act as the conservator to operate the enterprises until they are stabilized.

Although one or more of the other risks described in this SAI may also apply, the risks typically associated with U.S. Government and related obligations include: Credit Risk, Inflation Risk, Interest Rate Risk, Prepayment and Extension Risk, Reinvestment Risk and U.S. Government Obligations Risk. See Information Regarding Risks.

Variable- and Floating-Rate Obligations

Variable- and floating-rate obligations are debt instruments that provide for periodic adjustments in the interest rate and, under certain circumstances, varying principal amounts. Unlike a fixed interest rate, a variable, or floating, rate is one that rises and declines based on the movement of an underlying index of interest rates and may pay interest at rates that are adjusted periodically according to a specified formula. Variable- or floating-rate securities frequently include a demand feature enabling the holder to sell the securities to the issuer at par. In many cases, the demand feature can be exercised at any time. Some securities that do not have variable or floating interest rates may be accompanied by puts producing similar results and price characteristics. Variable-rate demand notes include master demand notes that are obligations that permit the investor to invest fluctuating amounts, which may change daily without penalty, pursuant to direct arrangements between the investor (as lender), and the borrower. The interest rates on these notes fluctuate. The issuer of such obligations normally has a corresponding right, after a given period, to prepay in its discretion the outstanding principal amount of the obligations plus accrued interest upon a specified number of days’ notice to the holders of such obligations. Because these obligations are direct lending arrangements between the lender and borrower, it is not contemplated that such instruments generally will be traded. There generally is not an established secondary market for these obligations. Accordingly, where these obligations are not secured by letters of credit or other credit support arrangements, the lender’s right to redeem is dependent on the ability of the borrower to pay principal and interest on demand. Such obligations frequently are not rated by credit rating agencies and may involve heightened risk of default by the issuer. Asset-backed securities, bank obligations, convertible securities, corporate debt securities, foreign securities, high yield securities, money market instruments, mortgage-backed securities, municipal securities, participation interests, stripped securities, U.S. Government and related obligations and other types of debt instruments may be structured as variable- and floating-rate obligations.

Most floating rate loans are acquired directly from the agent bank or from another holder of the loan by assignment. Most such loans are secured, and most impose restrictive covenants on the borrower. These loans are typically made by a syndicate of banks and institutional investors, represented by an agent bank which has negotiated and structured the loan and which is responsible generally for collecting interest, principal, and other amounts from the borrower on its own behalf and on behalf of the other lending institutions in the syndicate, and for enforcing its rights and the rights of the syndicate against the borrower. Each of the lending institutions, including the agent bank, lends to the borrower a portion of the total amount of the loan, and retains the corresponding interest in the loan. Floating rate loans may include delayed draw term loans and prefunded or synthetic letters of credit.

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A Fund’s or a Portfolio Fund’s ability to receive payments of principal and interest and other amounts in connection with loans held by it will depend primarily on the financial condition of the borrower. The failure by the Fund or Portfolio Fund to receive scheduled interest or principal payments on a loan would adversely affect the income of the Fund or Portfolio Fund and would likely reduce the value of its assets, which would be reflected in a reduction in the Fund’s or Portfolio Fund’s NAV. Banks and other lending institutions generally perform a credit analysis of the borrower before originating a loan or purchasing an assignment in a loan. In selecting the loans in which the Fund or Portfolio Fund will invest, however, the Investment Manager or a Portfolio Fund’s investment adviser will not rely on that credit analysis of the agent bank, but will perform its own investment analysis of the borrowers. The Investment Manager’s analysis or the analysis of a Portfolio Fund’s investment adviser may include consideration of the borrower’s financial strength and managerial experience, debt coverage, additional borrowing requirements or debt maturity schedules, changing financial conditions, and responsiveness to changes in business conditions and interest rates. Investments in loans may be of any quality, including “distressed” loans, and will be subject to the Fund’s or Portfolio Fund’s credit quality policy.

Loans may be structured in different forms, including assignments and participations. In an assignment, a Fund or Portfolio Fund purchases an assignment of a portion of a lender’s interest in a loan. In this case, the Fund or Portfolio Fund may be required generally to rely upon the assigning bank to demand payment and enforce its rights against the borrower, but would otherwise be entitled to all of such bank’s rights in the loan.

The borrower of a loan may, either at its own election or pursuant to terms of the loan documentation, prepay amounts of the loan from time to time. There is no assurance that a Fund or Portfolio Fund will be able to reinvest the proceeds of any loan prepayment at the same interest rate or on the same terms as those of the original loan.

Corporate loans in which a Fund or Portfolio Fund may purchase a loan assignment are made generally to finance internal growth, mergers, acquisitions, recapitalizations, stock repurchases, leveraged buy-outs, dividend payments to sponsors and other corporate activities. The highly leveraged capital structure of certain borrowers may make such loans especially vulnerable to adverse changes in economic or market conditions. The Fund or Portfolio Fund may hold investments in loans for a very short period of time when opportunities to resell the investments that the Investment Manager or a Portfolio Fund’s investment adviser believes are attractive arise.

Certain of the loans acquired by a Fund or Portfolio Fund may involve revolving credit facilities under which a borrower may from time to time borrow and repay amounts up to the maximum amount of the facility. In such cases, the Fund or Portfolio Fund would have an obligation to advance its portion of such additional borrowings upon the terms specified in the loan assignment. To the extent that the Fund or Portfolio Fund is committed to make additional loans under such an assignment, it will at all times designate cash or securities in an amount sufficient to meet such commitments.

Notwithstanding its intention in certain situations to not receive material, non-public information with respect to its management of investments in floating rate loans, the Investment Manager or a Portfolio Fund’s investment adviser may from time to time come into possession of material, non-public information about the issuers of loans that may be held in a Fund’s or Portfolio Fund’s portfolio. Possession of such information may in some instances occur despite the Investment Manager’s efforts or the efforts of a Portfolio Fund’s investment adviser to avoid such possession, but in other instances the Investment Manager or a Portfolio Fund’s investment adviser may choose to receive such information (for example, in connection with participation in a creditors’ committee with respect to a financially distressed issuer). As, and to the extent, required by applicable law, the Investment Manager’s ability or the ability of a Portfolio Fund’s investment adviser to trade in these loans for the account of the Fund or Portfolio Fund could potentially be limited by its possession of such information. Such limitations on the Investment Manager’s ability or the ability of a Portfolio Fund’s investment adviser to trade could have an adverse effect on the Fund or Portfolio Fund by, for example, preventing the Fund or Portfolio Fund from selling a loan that is experiencing a material decline in value. In some instances, these trading restrictions could continue in effect for a substantial period of time.

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In some instances, other accounts managed by the Investment Manager or a Portfolio Fund’s investment adviser may hold other securities issued by borrowers whose floating rate loans may be held in a Fund’s or Portfolio Fund’s portfolio. These other securities may include, for example, debt securities that are subordinate to the floating rate loans held in the Fund’s or Portfolio Fund’s portfolio, convertible debt or common or preferred equity securities. In certain circumstances, such as if the credit quality of the issuer deteriorates, the interests of holders of these other securities may conflict with the interests of the holders of the issuer’s floating rate loans. In such cases, the Investment Manager or a Portfolio Fund’s investment adviser may owe conflicting fiduciary duties to the Fund or Portfolio Fund and other client accounts. The Investment Manager or a Portfolio Fund’s investment adviser will endeavor to carry out its obligations to all of its clients to the fullest extent possible, recognizing that in some cases certain clients may achieve a lower economic return, as a result of these conflicting client interests, than if the Investment Manager’s client account or that of a Portfolio Fund’s investment adviser’s client accounts collectively held only a single category of the issuer’s securities.

Although one or more of the other risks described in this SAI may also apply, the risks typically associated with variable- or floating-rate obligations include: Counterparty Risk, Credit Risk, Interest Rate Risk, Liquidity Risk and Prepayment and Extension Risk. See Information Regarding Risks.

Warrants and Rights

Warrants and rights are types of securities that give a holder a right to purchase shares of common stock. Warrants usually are issued together with a bond or preferred stock and entitle a holder to purchase a specified amount of common stock at a specified price typically for a period of years. Rights usually have a specified purchase price that is lower than the current market price and entitle a holder to purchase a specified amount of common stock typically for a period of only weeks. Warrants may be used to enhance the marketability of a bond or preferred stock.

Warrants do not carry with them the right to dividends or voting rights and they do not represent any rights in the assets of the issuer. Warrants may be considered to have more speculative characteristics than certain other types of investments. In addition, the value of a warrant does not necessarily change with the value of the underlying securities, and a warrant ceases to have value if it is not exercised prior to its expiration date, if any. The potential exercise price of warrants or rights may exceed their market price, such as when there is no movement in the market price or the market price of the common stock declines, in which case the warrants may have little or no value.

Although one or more of the other risks described in this SAI may also apply, the risks typically associated with warrants and rights include: Convertible Securities Risk, Counterparty Risk, Credit Risk, Issuer Risk and Market Risk. See Information Regarding Risks.

Information Regarding Risks

The following is a summary of risks associated with the various securities, instruments, assets and investments as well as strategies and techniques that may be available to the Funds and the Portfolio Funds for investment. In this section the term “Fund” refers to a Fund or a Portfolio Fund, except where otherwise indicated. A Fund’s risk profile is largely determined by its portfolio holdings and principal investment strategies (see the Fund’s most recent annual or semiannual report for portfolio holdings information and see the Fund’s current prospectus for the description of the Fund’s principal investment strategies and principal risks). As discussed above, each Fund is permitted to invest in other securities, instruments, assets and investments, and may engage in strategies and techniques other than those described in its current prospectus, which subjects the Fund to the risks associated with these other securities, instruments, assets, investments, strategies and techniques.

An investment in a Fund is not a bank deposit and is not insured or guaranteed by any bank, the FDIC or any other government agency. One or more of the following risks may be associated with an investment in a Fund at any time:

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Active Management Risk

Each Fund is actively managed and its performance therefore will reflect, in part, the ability of the Investment Manager to make investment decisions that will achieve the Fund’s investment objective. Due to its active management, a Fund could underperform its benchmark index and/or other funds with similar investment objectives and/or strategies.

Allocation Risk

For any Fund that uses an asset allocation strategy in pursuit of its investment objective, there is a risk that the Fund’s allocation among asset classes, investments, managers, strategies and/or investment styles will cause the Fund’s shares to lose value or cause the Fund to underperform other funds with similar investment objectives and/or strategies, or that the investments themselves will not produce the returns expected.

Alternative Strategies Investment Risk

An investment in alternative investment strategies (Alternative Strategies), whether through direct investment or through a Portfolio Fund or other underlying fund, involves risks, which may be significant. Alternative Strategies may include strategies, instruments or other assets, such as derivatives, that seek investment returns uncorrelated with the broad equity and fixed income/debt markets, as well as those providing exposure to other markets (such as commodity markets), including but not limited to absolute (positive) return strategies. Alternative Strategies may fail to achieve their desired performance, market or other exposure, or their returns (or lack thereof) may be more correlated with the broad equity and/or fixed income/debt markets than was anticipated, and a Fund may lose money.

To the extent that a Portfolio Fund or other underlying fund is charged a performance (or incentive) fee (which would indirectly be borne by a Fund’s shareholders), such fees may create incentives for the Portfolio Fund’s or other underlying fund’s manager to make investments that are riskier or more speculative than in the absence of these fees. Because these fees are often based on both realized and unrealized appreciation, the fee may be greater than if it were based only on realized gains. In addition, a Portfolio Fund’s or other underlying fund’s manager may receive compensation for relative performance of the Portfolio Fund or other underlying fund even if the Portfolio Fund’s or other underlying fund’s overall returns are negative.

Asset-Backed Securities Risk

The value of a Fund’s asset-backed securities may be affected by, among other things, changes in interest rates, factors concerning the interests in and structure of the issuer or the originator of the receivables, the creditworthiness of the entities that provide any supporting letters of credit, surety bonds or other credit enhancements, or the market’s assessment of the quality of underlying assets. Asset-backed securities represent interests in, or are backed by, pools of receivables such as credit card, auto, student and home equity loans. They may also be backed by securities backed by these types of loans and others, such as mortgage loans. Asset-backed securities can have a fixed or an adjustable rate. Most asset-backed securities are subject to liquidity risk (the risk that it may not be possible for the Fund to liquidate the instrument at an advantageous time or price), and prepayment risk (the risk that the Fund will have to reinvest the money received in securities that have lower yields). In addition, the impact of prepayments on the value of asset-backed securities may be difficult to predict and may result in greater volatility. Rising or high interest rates tend to extend the duration of asset-backed securities, resulting in valuations that are volatile and sensitive to changes in interest rates.

Authorized Participant Concentration Risk

Only an Authorized Participant may engage in creation or redemption transactions directly with Portfolio Funds that are ETFs. An “Authorized Participant” is a participant of the Continuous Net Settlement System of the NSCC or the DTC that has executed a Participant Agreement with the Distributor, and accepted by the Transfer

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Agent. Authorized Participants may purchase creation units of ETF shares, and sell individual ETF shares on the NYSE Arca, Inc. (the Exchange). ETF Portfolio Funds have a limited number of institutions that may act as Authorized Participants, none of which are or will be obligated to engage in creation or redemption transactions. To the extent that these institutions exit the business or are unable or unwilling to proceed with creation and/or redemption orders with respect to the ETF Portfolio Fund and no other Authorized Participant is able or willing to step forward to create or redeem creation units, ETF Portfolio Fund shares may trade at a discount to NAV and possibly face trading halts and/or delisting from the Exchange. This risk is heightened in times of market stress, including at both the ETF Portfolio Fund share level and at the ETF Portfolio Fund holdings level.

Changing Distribution Level Risk

Each Fund normally expects to receive income which may include interest, dividends and/or capital gains, depending upon its investments. The distribution amounts paid by the Fund will vary and generally depend on the amount of income the Fund earns (less expenses) its portfolio holdings, and capital gains or losses it recognizes. A decline in the Fund’s income or net capital gains arising from its investments may reduce its distribution level.

Confidential Information Access Risk

In many instances, issuers of floating rate loans offer to furnish material, non-public information (Confidential Information) to prospective purchasers or holders of the issuer’s floating rate loans to help potential investors assess the value of the loan. The Investment Manager and its affiliates, including the investment adviser to the Portfolio Funds, may avoid the receipt of Confidential Information about the issuers of floating rate loans being considered for acquisition by a Fund or Portfolio Fund, or held by a Fund or Portfolio Fund. A decision not to receive Confidential Information from these issuers may disadvantage a by a Fund or Portfolio Fund as compared to other floating rate loan investors, and may adversely affect the price the Fund or the Portfolio Fund pays for the loans it purchases, or the price at which the Fund sells the loans. Further, in situations when holders of floating rate loans are asked, for example, to grant consents, waivers or amendments, the ability to assess the desirability thereof, may be compromised. For these and other reasons, it is possible that the decision not to receive Confidential Information could adversely affect a Fund’s or a Portfolio Fund’s performance.

Convertible Securities Risk

Convertible securities are subject to the usual risks associated with debt instruments, such as interest rate risk (the risk of losses attributable to changes in interest rates) and credit risk (the risk that the issuer of a debt instrument will default or otherwise become unable, or be perceived to be unable or unwilling, to honor a financial obligation, such as making payments to a Fund when due). Convertible securities also react to changes in the value of the common stock into which they convert, and are thus subject to market risk (the risk that the market values of securities or other investments that a Fund holds will fall, sometimes rapidly or unpredictably, or fail to rise). Because the value of a convertible security can be influenced by both interest rates and the common stock’s market movements, a convertible security generally is not as sensitive to interest rates as a similar debt instrument, and generally will not vary in value in response to other factors to the same extent as the underlying common stock. In the event of a liquidation of the issuing company, holders of convertible securities would typically be paid before the company’s common stockholders but after holders of any senior debt obligations of the company. A Fund may be forced to convert a convertible security before it otherwise would choose to do so, which may decrease a Fund’s return.

Correlation/Tracking Error Risk

The value of a Portfolio Fund that seeks returns that correlate with a market index (the Index) will generally decline when the performance of the Index declines. A number of factors may affect the Portfolio Fund’s ability to achieve a high degree of correlation with the Index, and there is no guarantee that the Portfolio Fund will

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achieve a high degree of correlation. Failure to achieve a high degree of correlation may prevent the Portfolio Fund from achieving its investment objective. The factors that may adversely affect the Portfolio Fund’s correlation with the Index include the size of the Portfolio Fund’s portfolio, fees, expenses, transaction costs, income items, valuation methodology, accounting standards, the effectiveness of sampling techniques (if applicable), changes in the Index and disruptions or illiquidity in the markets for the securities or other instruments in which the Portfolio Fund invests. Portfolio Funds that typically use a “full replication” approach in seeking to track the performance of the Index, which means they invest all, or substantially all, of their assets in the components of the Index in approximately the same proportion as their weighting in the Index. At times, these “full replication” Portfolio Funds may not have investment exposure to all components of the Index, or their weighting of investment exposure to such components may be different from that of the Index. Portfolio Funds that typically use a “representative sampling” approach in seeking to track the performance of the Index, which is an indexing strategy that involves investing in only some of the components of the Index that collectively are believed to have an investment profile similar to that of the Index, may not track the Index with the same degree of accuracy as would an investment vehicle replicating the entire Index. In addition, both full replication and representative sampling Portfolio Funds may invest in securities or other instruments not included in the Index. The Portfolio Fund may take or refrain from taking investment positions for various reasons, such as tax efficiency purposes, or to comply with regulatory restrictions, which may negatively affect the Portfolio Fund’s correlation with the Index. The Portfolio Fund may also be subject to large movements of assets into and out of the Portfolio Fund, potentially resulting in the Portfolio Fund being over- or under-exposed to certain components of the Index and may be impacted by Index reconstitutions and Index rebalancing events. Additionally, the Portfolio Fund’s foreign investments may trade on markets that may not be open on the same day or at the same time as the Portfolio Fund, which may cause a difference between the changes in the daily performance of the Portfolio Fund and changes in the level of the Index. Furthermore, the Portfolio Fund may need to execute currency trades that due to regulatory, legal and operational constraints will occur at a later date than the trading of the related security. Currency holdings may be valued at a different time and at different rates than that used by the Index. Holding cash balances may detract from the Portfolio Fund’s ability to track the Index. In addition, the Portfolio Fund’s NAV may deviate from the Index if the Portfolio Fund fair values a portfolio security at a price other than the price used by the Index for that security. The Portfolio Fund also bears management and other expenses and transaction costs in trading securities or other instruments, which the Index does not bear. Accordingly, the Portfolio Fund’s performance will likely fail to match the performance of the Index, after taking expenses into account. Any of these factors could decrease correlation between the performance of the Portfolio Fund and the Index and may hinder the Portfolio Fund’s ability to meet its investment objective. It is not possible to invest directly in an index.

Several factors may affect the Portfolio Fund’s ability to achieve a high degree of correlation with its current Index. Among these factors are: (1) the Portfolio Fund’s fees and expenses, including brokerage (which may be increased by high portfolio turnover) and the costs associated with the use of derivatives or other assets or instruments; (2) the Portfolio Fund holding less than all of the components of the Index or the Portfolio Fund holding investments not included in the Index; (3) the “representative sampling” strategy, where applicable, may not work as intended so as to sufficiently track the performance of the Index; (4) an imperfect correlation between the performance of instruments held by the Portfolio Fund, such as, among others, futures contracts, and the performance of the components of the Index; (5) bid-ask spreads (the effect of which may be increased by portfolio turnover); (6) holding instruments traded in a market that has become illiquid or disrupted; (7) the Portfolio Fund’s share prices being rounded to the nearest cent; (8) changes to the Index that are not disseminated in advance; (9) the need to conform the Portfolio Fund’s portfolio holdings to comply with investment restrictions or policies or regulatory or tax law requirements; (10) limit up or limit down trading halts on options or futures contracts which may prevent the Portfolio Fund from purchasing or selling options or futures contracts; (11) early and unanticipated closings of the markets on which the holdings of the Portfolio Fund trade, resulting in the inability of the Portfolio Fund to execute intended portfolio transactions; and (12) fluctuations in currency exchange rates. Also, Portfolio Fund rebalancings to the Index, disparities between estimated and actual purchases and redemptions of the Portfolio Fund may cause the Portfolio Fund to be over- or underexposed to the Index. This may result in greater tracking and correlation error.

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Counterparty Risk

The risk exists that a counterparty to a transaction in a financial instrument held by a Fund or by a special purpose or structured vehicle in which the Fund invests may become insolvent or otherwise fail to perform its obligations, including making payments to the Fund, due to financial difficulties. A Fund may obtain no or limited recovery in a bankruptcy or other re-organizational proceedings, and any recovery may be significantly delayed. Transactions that a Fund enters into may involve counterparties in the financial services sector and, as a result, events affecting the financial services sector may cause the Fund’s share value to fluctuate.

In the event of a counterparty’s (or its affiliate’s) insolvency, the Fund’s ability to exercise remedies, such as the termination of transactions, netting of obligations and realization on collateral, could be stayed or eliminated under new special resolution regimes adopted in the United States, the European Union (EU) and various other jurisdictions. Such regimes generally provide government authorities with broad authority to intervene when a financial institution is experiencing financial difficulty. In particular, the regulatory authorities could reduce, eliminate or convert to equity the liabilities to the Fund of a counterparty subject to such proceedings in the EU (sometimes referred to as a “bail in”).

Credit Risk

Credit risk is the risk that the value of loans or other debt instruments may decline if the borrower or the issuer thereof defaults or otherwise becomes unable or unwilling, or is perceived to be unable or unwilling, to honor its financial obligations, such as making payments to the Fund when due. Various factors could affect the actual or perceived willingness or ability of the borrower or the issuer to make timely interest or principal payments, including changes in the financial condition of the borrower or the issuer or in general economic conditions. Debt instruments backed by an issuer’s taxing authority may be subject to legal limits on the issuer’s power to increase taxes or otherwise to raise revenue, or may be dependent on legislative appropriation or government aid. Certain debt instruments are backed only by revenues derived from a particular project or source, rather than by an issuer’s taxing authority, and thus may have a greater risk of default. Credit rating agencies, such as S&P Global Ratings, Moody’s, Fitch, DBRS and KBRA, assign credit ratings to certain loans and debt instruments to indicate their credit risk. A rating downgrade by such agencies can negatively impact the value of such instruments. Lower-rated or unrated loans or instruments held by the Fund may present increased credit risk as compared to higher-rated loans or instruments. Non-investment grade loans or debt instruments may be subject to greater price fluctuations and are more likely to experience a default than investment grade loans or debt instruments and therefore may expose the Fund to increased credit risk. If the Fund purchases unrated loans or instruments, or if the ratings of such loans or instruments held by the Fund are lowered after purchase, the Fund will depend on analysis of credit risk more heavily than usual. If the issuer of a loan declares bankruptcy or is declared bankrupt, there may be a delay before the Fund can act on the collateral securing the loan, which may adversely affect the Fund. Further, there is a risk that a court could take action with respect to a loan that is adverse to the holders of the loan. Such actions may include invalidating the loan, the lien on the collateral, the priority status of the loan, or ordering the refund of interest previously paid by the borrower. Any such actions by a court could adversely affect the Fund’s performance. A default or expected default of a loan could also make it difficult for the Fund to sell the loan at a price approximating the value previously placed on it. In order to enforce its rights in the event of a default, bankruptcy or similar situation, the Fund may be required to retain legal or similar counsel. This may increase the Fund’s operating expenses and adversely affect its NAV. Loans that have a lower priority for repayment in an issuer’s capital structure may involve a higher degree of overall risk than more senior loans of the same borrower.

Cybersecurity Breaches, Systems Failure and Other Business Disruptions Risk

The Funds and their service providers, including the Investment Manager and its affiliates (Ameriprise Financial, which is the Investment Manager’s parent company, the Distributor and the Transfer Agent (together with the Investment Manager, referred to herein as “we,” “us” and “our”)), the Custodian and other service

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providers, as well as all their underlying service providers (collectively, the “Service Providers”), are heavily dependent on their respective employees, agents and other personnel (“Personnel”) and proprietary and third-party technology and infrastructure and related business, operational and information systems, networks, computers, devices, programs, applications, data and functions (collectively, “Systems”) to perform necessary business activities.

The Systems and Personnel that the Funds and the Service Providers rely upon may be vulnerable to significant disruptions and failures, including those relating to or arising from cybersecurity breaches (including intentional acts, e.g., cyber-attacks, hacking, phishing scams, unauthorized payment requests and other social engineering techniques aimed at Personnel or Systems, and unintentional events or activity), Systems malfunctions, user error, conduct (or misconduct) of or arising from Personnel and remote access to Systems (particularly important given the increased use of technologies such as the internet to conduct business. In addition, other events or circumstances — whether foreseeable, unforeseeable, or beyond our control, such as acts of war, other conflicts, terrorism, natural disaster, widespread disease, pandemic or other public health crises may result in, among other things, quarantines and travel restrictions, workforce displacement and loss or reduction in Personnel and other resources. In the above circumstances, the Funds and the Service Providers’ operations may be significantly impacted, or even temporarily halted. The Funds’ securities market counterparties or vendors may face the same or similar systems failure, cybersecurity breaches and other business disruptions risks.

Systems and Personnel disruptions and failures, particularly cybersecurity breaches, may result in (i) proprietary or confidential information or data including personal investor information (and that of beneficial owners of investors), being lost, withheld for ransom, misused, destroyed, stolen, released, corrupted or rendered unavailable, (ii) unauthorized access to Systems and loss of operational capacity, including from, but not limited to, denial-of-service attacks (i.e., efforts to make network services and other Systems unavailable to intended users), and (iii) the misappropriation of Fund or investor assets or sensitive information. Any such events could negatively impact Service Provider Personnel and Systems and may have significant adverse impacts on the Funds and their shareholders.

Systems and Personnel disruptions and failures such as cybersecurity breaches may cause delays or mistakes in materials provided to shareholders and may also interfere with, or negatively impact, the processing of Fund investor transactions, pricing of Fund investments, calculating Fund NAVs, and trading within a Fund’s portfolio, while causing or subjecting the Funds to potential financial losses as well as additional compliance, legal, and operational costs. Such events could negatively impact the Fund, its shareholders and the business, financial condition and performance or results of operations of the Service Providers.

The trend toward broad consumer and general public notification of Systems failures and cybersecurity breaches could exacerbate the harm to a Fund, its shareholders and Service Provider business, financial condition and performance or results of operations. Even if we and the Service Providers successfully protect our respective Systems from failures or cybersecurity breaches, we may incur significant expenses in connection with our responses to any such events, as well as the need for adoption, implementation and maintenance of appropriate security measures. We could also suffer harm to our business and reputation if attempted or actual cybersecurity breaches are publicized. We cannot be certain that evolving threats from cyber-criminals and other cyber-threat actors, exploitation of new vulnerabilities in our Systems, or other developments, or data thefts, System break-ins or inappropriate access will not compromise or breach the technology or other security measures protecting our Systems.

We routinely face and address evolving cybersecurity threats and have been able to detect and respond to these incidents to date without a material loss of client financial assets or information through the use of ongoing monitoring and continual improvement of our security capabilities and incident response manual. We have been threatened by phishing and spear phishing scams, social engineering attacks, account takeovers, introductions of malware, attempts at electronic break-ins, and the submission of fraudulent payment requests. Systems failures

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and cybersecurity breaches may be difficult to detect, may go undetected for long periods or may never be detected. The impact of such events may be compounded over time. Although we and the Funds evaluate the materiality of all Systems failures and cybersecurity breaches detected, we and the Funds may conclude that some such events are not material and may choose not to address them. Such conclusions may not prove to be correct.

Although we have established business continuity/disaster recovery plans (Continuity and Recovery Plans) designed to prevent or mitigate the effects of Systems and Personnel disruptions and failures and cybersecurity breaches, there are inherent limitations in Continuity and Recovery Plans. These limitations include the possibility that certain risks have not been identified that Continuity and Recovery Plans might not — despite testing and monitoring — operate as designed, be sufficient to stop or mitigate negative impacts, including financial losses, or that Continuity and Recovery Plans may otherwise be unable to achieve their objectives. The Funds and their shareholders could be negatively impacted as a result. In addition, the Funds cannot control the Continuity and Recovery Plans of the Service Providers. As a result, there can be no assurance that the Funds will not suffer financial losses relating to Systems or Personnel disruptions or failures or cybersecurity breaches affecting them or us in the future. The widespread use of work-from-home arrangements, such as during the COVID-19 pandemic, may increase these risks. The Investment Manager and its affiliates have systematically implemented strategies to address the operating environment spurred by the COVID-19 pandemic. The Investment Manager’s operations teams seek to operate without significant disruptions in service. Its Continuity and Recovery Plans take into consideration that a pandemic could be widespread and may occur in multiple waves, affecting different communities at different times with varying levels of severity. The Fund cannot, however, predict the impact that natural or man-made disasters and conditions, including the COVID-19 pandemic (and its variants), may have on the ability of us and Service Providers to continue ordinary business operations and technology functions over near- or longer-term periods. In addition, the Fund cannot control or dictate the Continuity and Recovery Plans of the Service Providers. As a result, there can be no assurance that the Funds will not suffer financial losses relating to Systems or Personnel disruptions or failures or cybersecurity breaches affecting them or us in the future.

Systems and Personnel disruptions and failures and cybersecurity breaches may necessitate significant investment to repair or replace impacted Systems. In addition, the Funds may incur substantial costs for risk management in connection with failures or interruptions of Systems, Personnel, Continuity and Recovery Plans and cybersecurity defense measures in order to attempt to prevent any such events or incidents in the future, which, if they should occur, may be prolonged and may negatively impact negatively impacting business operations.

Any insurance or other risk-shifting tools available to us in order to manage or mitigate the risks associated with Systems and Personnel disruptions and failures and cybersecurity breaches are generally subject to terms and limitations such as deductibles, coinsurance, limits and policy exclusions, as well as risk of counterparty denial of coverage, default or insolvency. While Ameriprise Financial and its affiliates maintain cyber liability insurance that provides both third-party liability and first-party liability coverages, this insurance may not be sufficient to protect us against all losses. In addition, contractual remedies may not be available with respect to Service Providers or may prove inadequate if available (e.g., because of limits on the liability of the Service Providers) to protect the Funds against all losses.

Stock and other market exchanges, financial intermediaries, issuers of, and counterparties to, the Funds’ investments and, in the case of ETFs, market makers and authorized participants, also may be adversely impacted by Systems and Personnel disruptions and failures and cybersecurity breaches, in their own businesses, subjecting them to the risks described here, as well as other additional or enhanced risks particular to their businesses, which could result in losses to the Funds and their shareholders. Issuers of securities or other instruments in which the Funds invest may also experience Systems and Personnel disruptions and failures and cybersecurity breaches, which could result in material adverse consequences for such issuers, which may cause the Funds’ investment in such issuers to lose money.

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Depositary Receipts Risk

Depositary receipts are receipts issued by a bank or trust company reflecting ownership of underlying securities issued by foreign companies. Some foreign securities are traded in the form of American Depositary Receipts and/or) Global Depositary Receipts. Depositary receipts involve risks similar to the risks associated with investments in foreign securities, including those associated with an issuer’s (and any of its related companies’) country of organization and places of business exposures, which may be related to the particular political, regulatory, economic, social and other conditions or events, including, for example, military confrontations and actions, war, terrorism, and disease/virus outbreaks and epidemics, occurring in the country and fluctuations in such country’s currency, as well as market risk tied to the underlying foreign company. In addition, holders of depositary receipts may have limited voting rights, may not have the same rights afforded to stockholders of a typical company in the event of a corporate action, such as an acquisition, merger or rights offering, and may experience difficulty in receiving company stockholder communications. There is no guarantee that a financial institution will continue to sponsor a depositary receipt, or that the depositary receipts will continue to trade on an exchange, either of which could adversely affect the liquidity, availability and pricing of the depositary receipt. Changes in foreign currency exchange rates will affect the value of depositary receipts and, therefore, may affect the value of your investment in the Fund. A potential conflict of interest exists to the extent that the Fund invests in ADRs for which the Fund’s custodian serves as depository bank.

Derivatives Risk

Derivatives may involve significant risks. Derivatives are financial contracts, traded on an exchange or in the over-the-counter (OTC) markets, with a value related to, or derived from, the value of an underlying asset(s) (such as a security, commodity or currency) or other reference point, such as an index, rate or other economic indicator (each an underlying reference). Derivatives that the Fund enters into may be standardized as to their terms or, alternately, privately negotiated between the Fund and a counterparty. Derivatives that constitute securities under federal laws may be privately placed or otherwise exempt from SEC registration, including certain Rule 144A eligible securities. Derivatives could result in Fund losses if the underlying reference does not perform as anticipated. Use of derivatives is a highly specialized activity that can involve investment techniques, risks, and tax planning different from those associated with more traditional investment instruments. A Fund’s derivatives strategy may not be successful and could result in substantial, potentially unlimited, losses to the Fund regardless of the Fund’s actual investment. A relatively small movement in the price, rate or other economic indicator associated with the underlying reference may result in substantial losses for a Fund. Derivatives may be, or over the term of the contract may become, more volatile than other types of investments and the use of derivatives may increase the volatility of a Fund’s NAV. Derivatives can increase a Fund’s risk exposure to underlying references, including the risk of an adverse credit event associated with the underlying reference (credit risk), the risk of an adverse movement in the value, price or rate of the underlying reference (market risk), the risk of an adverse movement in the value of underlying currencies (foreign currency risk) and the risk of an adverse movement in underlying interest rates (interest rate risk).

Derivatives may expose a Fund to additional risks, including the risk of loss due to a derivative position that is imperfectly correlated with the underlying reference it is intended to hedge or replicate (correlation risk), the risk that a counterparty will fail to perform as agreed (counterparty risk), the risk that a hedging strategy may fail to mitigate losses, and may offset gains (hedging risk), the risk that the return on an investment may not keep pace with inflation (inflation risk), the risk that losses may be greater than the amount invested (leverage risk), the risk that the Fund may be unable to sell an investment at an advantageous time or price (liquidity risk), the risk that the investment may be difficult to value (pricing risk), and the risk that price or value of the investment fluctuates significantly over short periods of time (volatility risk). The value of derivatives may be influenced by a variety of factors, including national and international political and economic developments. Potential changes

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to the regulation of the derivatives markets may make derivatives more costly, may limit the amount of trading activity in the market for particular types of derivatives, or may otherwise adversely affect the value or performance of derivatives. See Permissible Fund Investments — Derivatives — Risk of Government Regulation of Derivatives above for more information on recent regulatory actions of the SEC and the European Union regarding derivatives. Finally, a common provision in over-the-counter derivative contracts (including some contracts for cleared swaps) permits the counterparty to terminate any such contract between it and the Fund, if the value of the Fund’s total net assets declines below a specified level over a given time period. Factors that may contribute to such a decline (which usually must be substantial) include significant shareholder redemptions and/or a marked decrease in the market value of the Fund’s investments. Any such termination of the Fund’s derivative contracts may adversely affect the Fund (for example, by increasing losses and/or costs, and/or preventing the Fund from fully implementing its investment strategies).

Derivatives Risk — Forward Contracts Risk. A forward contract is an over-the-counter derivative transaction between two parties to buy or sell a specified amount of an underlying reference at a specified price (or rate) on a specified date in the future. If the particular underlying reference is delivered by the seller to the buyer, then the forward contract can be described as a “deliverable forward”. But, instead of requiring delivery of the underlying reference at settlement, a forward contract may be a “non-deliverable forward,” meaning that the terms of the contract require the seller to make a payment to the buyer (if the market value of the underlying reference is greater than the agreed upon price) or the buyer to make a payment to the seller (if that market value is less than the agreed upon price). Forward contracts are negotiated on an individual basis and the type of forward contracts traded by the Fund are not standardized or traded on exchanges. The market for forward contracts is substantially unregulated (there is no limit on daily price movements and speculative position limits are not applicable). The principals who deal in certain forward markets are not required to continue to make markets in the underlying references in which they trade and these markets can experience periods of illiquidity, sometimes of significant duration. There have been periods during which certain participants in forward contract markets have refused to quote prices for certain underlying references or have quoted prices with an unusually wide spread between the price at which they were prepared to buy and that at which they were prepared to sell. At or prior to maturity of a forward contract, a Fund may enter into an offsetting contract and may incur a loss to the extent there has been adverse movement in forward contract prices. The liquidity of the markets for forward contracts depends on participants entering into offsetting transactions rather than making or taking delivery. To the extent participants make or take delivery, liquidity in the market for forwards could be reduced. A relatively small price movement in a forward contract may result in substantial losses to a Fund, exceeding the amount of any margin paid by the Fund in respect of the contract. The use of forwards may increase the volatility of a Fund’s NAV. Forward contracts can increase a Fund’s risk exposure to underlying references and their attendant risks, such as credit risk, market risk, foreign currency risk and interest rate risk, while also exposing the Fund to correlation risk, counterparty risk, hedging risk, inflation risk, leverage risk, liquidity risk, pricing risk and volatility risk.

A forward foreign currency contract is a derivative (forward contract) in which the underlying reference is a country’s or region’s currency. A Fund may agree to buy or sell a country’s or region’s currency at a specific price on a specific date in the future. A forward foreign currency contract may be a deliverable or a non-deliverable forward, depending upon the specific terms of the contract. These instruments may fall in value (sometimes dramatically) due to foreign market downswings or foreign currency value fluctuations, subjecting a Fund to foreign currency risk (the risk that Fund performance may be negatively impacted by foreign currency strength or weakness relative to the U.S. dollar, particularly if the Fund exposes a significant percentage of its assets to currencies other than the U.S. dollar). The effectiveness of any currency hedging strategy by a Fund may be reduced by the Fund’s inability to precisely match forward contract amounts and the value of securities involved. Forward foreign currency contracts used for hedging may also limit any potential gain that might result from an increase or decrease in the value of the currency. A Fund may use these instruments to gain leveraged exposure to currencies, which increases the Fund’s risk exposure and the possibility of losses. Unanticipated changes in the currency markets could result in reduced performance for a Fund. When a Fund converts its foreign currencies into U.S. dollars, it may incur currency conversion costs due to the spread between the prices at which it may buy and sell various currencies in the market.

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A forward interest rate agreement is a derivative whereby the buyer locks in an interest rate at a future settlement date. If the interest rate on the settlement date exceeds the lock rate, the buyer pays the seller the difference between the two rates (based on the notional value of the agreement). If the lock rate exceeds the interest rate on the settlement date, the seller pays the buyer the difference between the two rates (based on the notional value of the agreement). A Fund may act as a buyer or a seller.

Derivatives Risk — Futures Contracts Risk. A futures contract is an exchange-traded derivative transaction between two parties in which a buyer (holding the “long” position) agrees to pay a fixed price (or rate) at a specified future date for delivery of an underlying reference from a seller (holding the “short” position). Instead of requiring delivery of the underlying reference at settlement, a futures contracts may require the seller to make a payment to the buyer (if the market value of the underlying reference is greater than the agreed upon price) or the buyer to make a payment to the seller (if that market value is less than the agreed upon price). Regardless of the type of settlement (i.e., by delivery or by cash payment), the seller benefits if the market price at settlement is less than the agreed upon price, while the buyer benefits if the market price is more than the agreed upon price. Futures contract markets may be, or over the term of the contract may become, highly volatile, and futures contracts may be or become illiquid. Futures exchanges may limit fluctuations in futures contract prices by imposing a maximum permissible daily price movement. A Fund may be disadvantaged if it is prohibited from executing a trade outside the daily permissible price movement. At or prior to maturity of a futures contract, a Fund may enter into an offsetting contract and may incur a loss to the extent there has been adverse movement in futures contract prices. The liquidity of the futures markets depends on participants entering into offsetting transactions rather than making or taking delivery of the underlying reference. Although, disruptions in the market for delivery of the underlying reference, may adversely impact liquidity (i.e., reduce liquidity) in the related futures market. Positions in futures contracts may be closed out only on the exchange on which they were entered into or through a linked exchange, and no secondary market exists for such contracts. In order to secure future payment obligations, the Fund will be required to deposit cash or securities (referred to as “initial margin”) when it enters into a futures contract. The amount of initial margin required is relatively small compared to the level of market exposure obtained through the futures contract. Futures positions are marked to market each day and gains or losses on the contract (known as “variation margin”) must be paid to or by a Fund. Because of the low initial margin deposits normally required in futures trading relative to the level of market exposure obtained through a contract, it is possible that the Fund may employ a high degree of leverage in the portfolio. As a result, a relatively small price movement in a futures contract may result in substantial losses to a Fund, exceeding the amount of the margin deposited. For certain types of futures contracts (including any short position in a contract), losses are potentially unlimited. The use of futures may increase the volatility of a Fund’s NAV. Futures contracts executed on foreign exchanges (if any) may not provide the same protection as U.S. exchanges. Futures contracts can increase a Fund’s risk exposure to underlying references and their attendant risks, such as credit risk, market risk, foreign currency risk and interest rate risk, while also exposing the Fund to correlation risk, counterparty risk, hedging risk, inflation risk, leverage risk, liquidity risk, pricing risk and volatility risk.

A bond (or debt instrument) future is a derivative that is an agreement for the contract holder to buy or sell (or make a payment based upon changes in the value of) a bond or other debt instrument, a basket of bonds or other debt instrument, or the bonds or other debt instruments in an index on a specified date at a predetermined price. The buyer (long position) of a bond future is obliged to buy the underlying reference at the agreed price on expiry of the future. If cash settled, a bond future requires the buyer (seller) to make payments to the seller (buyer) for any depreciation (appreciation) in the value of the underlying reference over the term of the contract.

A commodity-linked future is a derivative that is an agreement to buy or sell one or more commodities (such as crude oil, gasoline and natural gas), basket of commodities or indices of commodity futures at a specific date in the future at a specific price. If cash settled, a commodity-linked future requires the buyer (seller) to make payments to the seller (buyer) for any depreciation (appreciation) in the value of the underlying reference over the term of the contract.

A currency future, also an FX future or foreign exchange future, is a derivative that is an agreement to exchange one currency for another at a specified date in the future at a price (exchange rate) that is fixed on the

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purchase date. If cash settled, a currency future requires the buyer (seller) to make payments to the seller (buyer) for any depreciation (appreciation) in the value of the underlying reference over the term of the contract.

An equity future is a derivative that requires the contract holder to buy or sell a specified amount of an individual equity, a basket of equities or the securities in an equity index on a specified date at a price agreed to by the parties when they enter into the contract. If cash settled, an equity future requires the buyer (seller) to make payments to the seller (buyer) for any depreciation (appreciation) in the value of the underlying reference over the term of the contract.

An interest rate future is a derivative that is an agreement whereby the buyer and seller agree to the future delivery of an interest-bearing instrument on a specific date at a pre-determined price. Examples include Treasury-bill futures, Treasury-bond futures and Eurodollar futures. Some interest rate futures may be an agreement that requires the buyer (seller) to make payments to the seller (buyer) in the future if a particular underlying reference interest rate decreases (increases) over the term of the contract.

Derivatives Risk — Inverse Floaters Risk. Inverse variable or floating rate obligations, sometimes referred to as inverse floaters, are a type of over-the-counter derivative debt instrument with a variable or floating coupon rate that moves in the opposite direction of an underlying reference, typically short-term interest rates. As short-term interest rates go down, the holders of the inverse floaters receive more income and, as short-term interest rates go up, the holders of the inverse floaters receive less income. Variable rate securities provide for a specified periodic adjustment in the coupon rate, while floating rate securities have a coupon rate that changes whenever there is a change in a designated benchmark index or the issuer’s credit rating. While inverse floaters tend to provide more income than similar term and credit quality fixed-rate bonds, they may also exhibit greater volatility in price movement, which could result in significant losses for a Fund. An inverse floater may have the effect of investment leverage to the extent that its coupon rate varies by a magnitude that exceeds the magnitude of the change in the index or reference rate of interest, which could result in increased losses for a Fund. There is a risk that the current interest rate on variable and floating rate instruments may not accurately reflect current market interest rates or adequately compensate the holder for the current creditworthiness of the issuer. Some inverse floaters are structured with liquidity features and may include market-dependent liquidity features that may expose a Fund to greater liquidity risk. Inverse floaters can increase a Fund’s risk exposure to underlying references and their attendant risks, such as credit risk, market risk, foreign currency risk and interest rate risk, while also exposing the Fund to correlation risk, counterparty risk, hedging risk, inflation risk, leverage risk, liquidity risk, pricing risk and volatility risk.

Derivatives Risk — Options Risk. Options are derivatives that give the purchaser the right to buy (in the case of a call option) or sell (in the case of a put option) an underlying reference from or to a counterparty at a specified price (the strike price) on or before an expiration date. A Fund may purchase or write put and call options on an underlying reference it is otherwise permitted to invest in or to which it is otherwise permitted to have economic exposure. Writing an option is also referred to as selling that option. When writing options, a Fund is exposed to the risk that it may be required to buy or sell the underlying reference at a disadvantageous price on or before the expiration date. Or, if the option is cash settled, then the Fund is exposed to the risk that it may be required to make payments to the other party to the contract based upon changes in the value of the underlying reference over the term of the contract. If a Fund sells a put option that settles by delivery of the underlying, the Fund may be required to buy the underlying reference at a strike price that is above market price, resulting in a loss. If the put option sold by the Fund is cash settled, then that loss would be in the form of a payment that corresponds to the amount by which the strike price under the contract exceeds the market price of the underlying reference. If a Fund sells a call option that settles by delivery of the underlying, the Fund may be required to sell the underlying reference at a strike price that is below market price, resulting in a loss. If the call option sold by the Fund is cash settled, then that loss would be in the form of a payment that corresponds to the amount by which the market price of the underlying reference exceeds the strike price under the contract. If a Fund sells a call option that is not covered (meaning that the Fund does not own the underlying reference), the Fund’s losses are potentially unlimited. Options may involve economic leverage, which could result in greater

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volatility in price movement. Options may be traded on an exchange or in the over-the-counter market. At or prior to maturity of an options contract, a Fund may enter into an offsetting contract and may incur a loss to the extent there has been adverse movement in options prices. Options can increase a Fund’s risk exposure to underlying references such as credit risk, market risk, foreign currency risk and interest rate risk, while also exposing the Fund to correlation risk, counterparty risk, hedging risk, leverage risk, inflation risk, liquidity risk, pricing risk and volatility risk.

Derivatives Risk — Structured Investments Risk. Structured investments are over-the-counter derivatives that provide principal and/or interest payments based on the value of an underlying reference(s). Structured investments typically provide interest income, thereby offering a potential yield advantage over investing directly in an underlying reference. Structured investments may lack a liquid secondary market and their prices or value can be volatile which could result in significant losses for a Fund. In some cases, depending on its terms, a structured investment may provide that principal and/or interest payments may be adjusted below zero resulting in a potential loss of principal and/or interest payments. Additionally, the particular terms of a structured investment may create economic leverage by requiring payment by the issuer of an amount that is a multiple of the price change of the underlying reference. Economic leverage will increase the volatility of structured investment prices, and could result in increased losses for a Fund. A Fund’s use of structured instruments may not work as intended. If structured investments are used to reduce the duration of a Fund’s portfolio, this may limit the Fund’s return when having a longer duration would be beneficial (for instance, when interest rates decline). Structured investments can increase a Fund’s risk exposure to underlying references and their attendant risks, such as credit risk, market risk, foreign currency risk and interest rate risk, while also exposing the Fund to correlation risk, counterparty risk, hedging risk, inflation risk, leverage risk, liquidity risk, pricing risk and volatility risk.

A commodity-linked structured note is a derivative (structured investment) that has principal and/or interest payments based on the market price of one or more particular commodities (such as crude oil, gasoline and natural gas), a basket of commodities, indices of commodity futures or other economic variable. If payment of interest on a commodity-linked structured note is linked to the value of a particular commodity, basket of commodities, commodity index or other economic variable, a Fund might receive lower interest payments (or not receive any of the interest due) on its investments if there is a decline in the value of the underlying reference. Further, to the extent that the amount of principal to be repaid upon maturity is linked to the value of a particular commodity, commodity index or other economic variable, a Fund might not receive a portion (or any) of the principal at maturity of the investment or upon earlier exchange. At any time, the risk of loss associated with a particular structured note in a Fund’s portfolio may be significantly higher than the value of the note. A liquid secondary market may not exist for the commodity-linked structured notes held in a Fund’s portfolio, which may make it difficult for the notes to be sold at a price acceptable to the Investment Manager or a Portfolio Fund’s investment adviser to accurately value them.

An equity-linked note (ELN) is a derivative (structured investment) that has principal and/or interest payments based on the value of a single equity security, a basket of equity securities or an index of equity securities, and generally has risks similar to these underlying equity securities. ELNs may be leveraged or unleveraged. An ELN typically provides interest income, thereby offering a yield advantage over investing directly in an underlying equity. The Fund may purchase ELNs that trade on a securities exchange or those that trade on the over-the-counter markets, as well as in privately negotiated transactions with the issuer of the ELN. Investments in ELNs are also subject to liquidity risk, which may make ELNs difficult to sell and value. The liquidity of unlisted ELNs is normally determined by the willingness of the issuer to make a market in the ELN. While the Fund will seek to purchase ELNs only from issuers that it believes to be willing and able to, repurchase the ELN at a reasonable price, there can be no assurance that the Fund will be able to sell at such a price. Furthermore, such inability. This to sell may impair the Fund’s ability to enter into other transactions at a time when doing so might be advantageous. The Fund’s investments in ELNs have the potential to lead to significant losses, including the amount the Fund invested in the ELN, because ELNs are subject to the market and volatility risks associated with their underlying equity. In addition, because ELNs often take the form of unsecured notes of the issuer, the Fund would be subject to the risk that the issuer may default on its obligations under the ELN,

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thereby subjecting the Fund to the further risk of being too concentrated in the securities (including ELNs) of that issuer. However, the Fund typically considers ELNs alongside other securities of the issuer in its assessment of issuer concentration risk. In addition, ELNs may exhibit price behavior that does not correlate with the underlying securities. ELNs may also be subject to leverage risk. The Fund may or may not hold an ELN until its maturity. ELNs also include participation notes.

Derivatives Risk — Swaps Risk. Derivatives may involve significant risks. In a typical swap transaction, two parties agree to exchange an amount equal to the return, based upon an agreed-upon notional value, earned on a specified underlying reference for a fixed return or the return from another underlying reference during a specified period of time. Swaps may be, or over the term of the contract may become, difficult to value and may be illiquid. Swaps could result in Fund losses if the underlying asset or reference does not perform as anticipated. Swaps create significant investment leverage such that a relatively small price movement in a swap may result in immediate and substantial losses to a Fund. A Fund may only close out a swap with its particular counterparty, and may only transfer a position with the consent of that counterparty. Additionally, every swap is subject to bankruptcy and insolvency laws, which could delay or limit the Fund’s recovery if the counterparty to a particular swap defaults on its obligation to make payments under the swap, or the Fund terminates that swap, in either case as a result of the counterparty’s bankruptcy or insolvency. In any bankruptcy or insolvency situation, the Fund may lose the benefit of any payments previously made by the Fund to the counterparty, or collect only a portion of what it is otherwise entitled to, with any such collection involving significant costs or delays. Certain swaps, such as short swap transactions and total return swaps, have the potential for unlimited losses, regardless of the size of the initial investment. Swaps can increase a Fund’s risk exposure to underlying references and their attendant risks, such as credit risk, market risk, foreign currency risk and interest rate risk, while also exposing a Fund to correlation risk, counterparty risk, hedging risk, inflation risk, leverage risk, liquidity risk, pricing risk and volatility risk.

A commodity-linked swap is a derivative (swap) that is an agreement where the underlying reference is the market price of one or more particular commodities (such as crude oil, gasoline and natural gas), basket of commodities or indices of commodity futures.

Contracts for differences are swap arrangements in which the parties agree that their return (or loss) will be based on the relative performance of two different groups or baskets of securities or other instruments. Often, one or both baskets will be an established securities index. A Fund’s return will be based on changes in value of theoretical long futures positions in the securities comprising one basket (with an aggregate face value equal to the notional amount of the contract for differences) and theoretical short futures positions in the securities comprising the other basket. A Fund also may use actual long and short futures positions and achieve similar market exposure by netting the payment obligations of the two contracts. If the short basket outperforms the long basket, a Fund will realize a loss — even in circumstances when the securities in both the long and short baskets appreciate in value.

A credit default swap (including a swap on a credit default index, sometimes referred to as a credit default swap index) is a derivative and special type of swap where one party pays, in effect, an insurance premium through a stream of payments to another party in exchange for the right to receive a specified return upon the occurrence of a particular credit event by one or more third parties, such as bankruptcy, default or a similar event. A credit default swap may be embedded within a structured note or other derivative instrument. Credit default swaps enable an investor to buy or sell protection against such a credit event (such as an issuer’s bankruptcy, restructuring or failure to make timely payments of interest or principal). Credit default swap indices are indices that reflect the performance of a basket of credit default swaps and are subject to the same risks as credit default swaps. If such a default were to occur, any contractual remedies that a Fund may have may be subject to bankruptcy and insolvency laws, which could delay or limit the Fund’s recovery. Thus, if the counterparty under a credit default swap defaults on its obligation to make payments thereunder, as a result of its bankruptcy or otherwise, a Fund may lose such payments altogether, or collect only a portion thereof, which collection could involve costs or delays. A Fund’s return from investment in a credit default swap index may not match the return of the referenced index. Further, investment in a credit default swap index could result in losses if the referenced

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index does not perform as expected. Unexpected changes in the composition of the index may also affect performance of the credit default swap index. If a referenced index has a dramatic intraday move that causes a material decline in a Fund’s net assets, the terms of the Fund’s credit default swap index may permit the counterparty to immediately close out the transaction. In that event, a Fund may be unable to enter into another credit default swap index or otherwise achieve desired exposure, even if the referenced index reverses all or a portion of its intraday move.

An inflation rate swap is a derivative typically used to transfer inflation risk from one party to another through an exchange of cash flows. In an inflation rate swap, one party pays a fixed rate on a notional principal amount, while the other party pays a floating rate linked to an inflation index, such as the Consumer Price Index (CPI).

An interest rate swap is a derivative in which two parties agree to exchange interest rate cash flows, based on a specified notional amount from a fixed rate to a floating rate (or vice versa) or from one floating rate to another. Interest rate swaps can be based on various measures of interest rates, including swap rates, Treasury rates, foreign interest rates and other reference rates.

Total return swaps are derivative swap transactions in which one party agrees to pay the other party an amount equal to the total return of a defined underlying reference during a specified period of time. In return, the other party would make periodic payments based on a fixed or variable interest rate or on the total return of a different underlying reference.

Early Close/Late Close/Trading Halt Risk

An exchange or market may close early, close late or issue trading halts on specific securities, or the ability to buy or sell certain securities may be restricted, which may result in a Portfolio Fund that in an ETF being unable to buy or sell these securities. In these circumstances, the ETF Portfolio Fund may be unable to rebalance its portfolio, may be unable to accurately price its investments, may incur substantial trading losses and/or may be prevented from sufficiently tracking the performance of the Index.

Emerging Markets Securities Risk

Securities issued by foreign governments or companies in emerging market countries, such as China, Russia and certain countries in Eastern Europe, the Middle East, Asia, Latin America or Africa, are more likely to have greater exposure to the risks of investing in foreign securities that are described in Foreign Securities Risk. In addition, emerging market countries are more likely to experience instability resulting, for example, from rapid changes or developments in social, political, economic or other conditions. Their economies are usually less mature and their securities markets are typically less developed with more limited trading activity (i.e., lower trading volumes and less liquidity) than more developed countries. Emerging market securities tend to be more volatile, and may be more susceptible to market manipulation, than securities in more developed markets. Many emerging market countries are heavily dependent on international trade and have fewer trading partners, which makes them more sensitive to world commodity prices and economic downturns in other countries. Some emerging market countries have a higher risk of currency devaluations, and some of these countries may experience periods of high inflation or rapid changes in inflation rates and may have hostile relations with other countries. Due to the differences in the nature and quality of financial information of issuers of emerging market securities, including auditing and financial reporting standards, financial information and disclosures about such issuers may be unavailable or, if made available, may be considerably less reliable than publicly available information about other foreign securities.

Operational and Settlement Risks of Securities in Emerging Markets. In addition to having less developed securities markets, banks in emerging markets that are eligible foreign sub-custodians may be recently organized, lack extensive operating experience or lack effective government oversight or regulation. In addition, there may be

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legal restrictions or limitations on the ability of a Fund to recover assets held in custody by a foreign sub-custodian in the event of the bankruptcy of the sub-custodian. Because settlement systems may be less organized than in developed markets and because delivery versus payment settlement may not be possible or reliable, there may be a greater risk that settlement may be delayed and that cash or securities of a Fund may be lost because of failures of or defects in the system, including fraud or corruption. Settlement systems in emerging markets also have a higher risk of failed trades.

Risks Related to Currencies and Corporate Actions in Emerging Markets. Risks related to currencies and corporate actions are also greater in emerging market countries than in developed countries. For example, some emerging market countries may have fixed or managed currencies that are not free-floating against the U.S. dollar. Further, certain currencies may not be traded internationally, or countries may have varying exchange rates. Some emerging market countries have a higher risk of currency devaluations, and some of these countries may experience sustained periods of high inflation or rapid changes in inflation rates which can have negative effects on a country’s economy and securities markets. Corporate action procedures in emerging market countries may be less reliable and have limited or no involvement by the depositories and central banks. Lack of standard practices and payment systems can lead to significant delays in payment.

Risks Related to Corporate and Securities Laws in Emerging Markets. Securities laws in emerging markets may be relatively new and unsettled and, consequently, there is a risk of rapid and unpredictable change in laws regarding foreign investment, securities regulation, title to securities and shareholder rights. Accordingly, foreign investors may be adversely affected by new or amended laws and regulations. In addition, the systems of corporate governance to which issuers in certain emerging markets are subject may be less advanced than the systems to which issuers located in more developed countries are subject, and therefore, shareholders of such issuers may not receive many of the protections available to shareholders of issuers located in more developed countries. These risks may be heightened in China and Russia.

Risks of Investments in Russia. A Fund may invest a portion of its assets in securities issued by companies located in Russia. The Russian securities market is exposed to a variety of risks described above in “Emerging Market Securities Risk” not encountered in more developed markets. The Russian securities market is relatively new, and a substantial portion of securities transactions are privately negotiated outside of stock exchanges. The inexperience of the Russian securities market and the limited volume of trading in securities in the market may make obtaining accurate prices on portfolio securities from independent sources more difficult than in more developed markets.

Because of the recent formation of the Russian securities markets, the relatively underdeveloped state of Russia’s banking and telecommunication systems and the legal and regulatory framework in Russia, settlement, clearing and registration of securities transactions are subject to additional risks. Prior to 2013, there was no central registration system for equity share registration in Russia and registration was carried out either by the issuers themselves or by registrars located throughout Russia. These registrars may not have been subject to effective state supervision or licensed with any governmental entity. In 2013, Russia established the National Settlement Depository (“NSD”) as a recognized central securities depository, and title to Russian equities is now based on the records of the NSD and not on the records of the local registrars. The implementation of the NSD is generally expected to decrease the risk of loss in connection with recording and transferring title to securities; however, loss may still occur. Additionally, issuers and registrars remain prominent in the validation and approval of documentation requirements for corporate action processing in Russia, and there remain inconsistent market standards in the Russian market with respect to the completion and submission of corporate action elections. To the extent that the Fund suffers a loss relating to title or corporate actions relating to its portfolio securities, it may be difficult for the Fund to enforce its rights or otherwise remedy the loss.

In addition, Russia also may attempt to assert its influence in the region through economic or military measures, as it did with Georgia in the summer of 2008 and Ukraine in 2014 and 2022. Russia launched a large-scale invasion of Ukraine in February 2022, significantly amplifying already existing geopolitical tensions. The

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extent and duration of the military action, the resulting sanctions or other punitive actions, the resulting future market disruptions, including declines in its stock markets, the value of Russian sovereign debt and the value of the ruble against the U.S. dollar, are impossible to predict, but have been and could continue to be significant. Any such disruptions caused by Russian military action or other hostile actions (including cyberattacks and espionage) or resulting actual and threatened responses to such activity, including potential widening of the scope of the conflict, purchasing and financing restrictions, potential suspension of trading Russian securities on stock exchanges, boycotts or changes in consumer or purchaser preferences, sanctions, tariffs or cyberattacks on the Russian government, Russian companies or Russian individuals, including politicians, may impact Russia’s economy and Russian issuers of securities in which the Fund invests. Actual and threatened responses to such military action have impacted, and may continue to impact the markets for certain Russian commodities, such as oil and natural gas, as well as other sectors of the Russian economy, and may likely have collateral impacts on such sectors globally. Further, several large corporations and U.S. states have announced plans to divest interests or otherwise curtail business dealings with certain Russian businesses.

Governments in the United States, Canada, the United Kingdom, the European Union and many other countries (collectively, the “Sanctioning Bodies”) have imposed broad-ranging economic sanctions, which may consist of banning Russia from global payments systems that facilitate cross-border payments, prohibiting certain securities trades, certain private transactions in the energy sector, asset freezes and prohibition of all business, against certain Russian individuals (including politicians) both inside Russia and globally, as well as Russian corporate and banking entities. The Sanctioning Bodies, and/or others, could also institute or threaten further sanctions, which may result in the decline of the value and liquidity of Russian securities, downgrades in the credit ratings of Russia or Russian issuers, a further weakening of the ruble or other adverse consequences for the Russian economy. These sanctions may include the immediate freeze of Russian securities and/or funds invested in prohibited assets, impairing the ability of a Fund to buy, sell, receive or deliver those securities and/or assets. Sanctions may also result in Russia taking counter measures or retaliatory actions which may further impair the value and liquidity of Russian securities. For instance, in response to sanctions, the government of Russia imposed capital controls to restrict movements of capital entering and exiting the country and the Russian Central Bank suspended the sales of Russian securities by non-residents of Russia on its local stock exchange. Any market disruptions caused by Russian military action, resulting sanctions and/or counter measures or actions thereto may magnify the impact of other risks to the Fund. Market events are rapidly evolving and present uncertainty and risk with respect to markets globally and the performance of the Fund and its investments could be negatively impacted.

China Stock Connect Risk. The risks noted here are in addition to the risks described under Emerging Market Securities Risk. A Fund or a Portfolio Fund may, directly or indirectly (through, for example, participatory notes or other types of equity-linked notes), purchase shares in mainland China-based companies that trade on Chinese stock exchanges such as the Shanghai Stock Exchange and the Shenzhen Stock Exchange (China A-Shares) through the Shanghai and Shenzhen-Hong Kong Stock Connect (China Stock Connect), or that may be available in the future through additional stock connect programs, a mutual market access program designed to, among other things, enable foreign investment in the People’s Republic of China (PRC) via brokers in Hong Kong. There are significant risks inherent in investing in China A-Shares through China Stock Connect. The underdeveloped state of PRC’s investment and banking systems subjects the settlement, clearing, and registration of securities transactions to heightened risks. Specifically, trading can be affected by a number of issues. China Stock Connect can only operate when both PRC and Hong Kong markets are open for trading and when banking services are available in both markets on the corresponding settlement days. As such, if one or both markets are closed on a U.S. trading day, a Fund or a Portfolio Fund may not be able to dispose of its China A-Shares in a timely manner, which could adversely affect a Fund’s or a Portfolio Fund’s performance. Because China Stock Connect is relatively new, its effects on the market for trading China A-Shares are uncertain. In addition, the trading, settlement and information technology systems required to operate China Stock Connect are relatively new and continuing to evolve. In the event that the relevant systems do not function properly, trading through China Stock Connect could be disrupted.

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PRC regulations require that, in order to sell its China A-Shares, a Fund must pre-deliver the China A-Shares to a broker. If the China A-Shares are not in the broker’s possession before the market opens on the day of sale, the sell order will be rejected. This requirement could also limit a Fund’s ability to dispose of its China A-Shares purchased through China Stock Connect in a timely manner. Additionally, China Stock Connect is subject to daily quota limitations on purchases in the PRC. Once the daily quota is reached, orders to purchase additional China A-Shares through China Stock Connect will be rejected. A Fund’s investment in China A-Shares may only be traded through China Stock Connect and is not otherwise transferable. China Stock Connect utilizes an omnibus clearing structure, and the Fund’s shares will be registered in its custodian’s name on the Central Clearing and Settlement System. This may limit the ability of the Investment Manager to effectively manage a Fund, and may expose the Fund to the credit risk of its custodian or to greater risk of expropriation. Investment in China A-Shares through China Stock Connect may be available only through a single broker that is an affiliate of the Fund’s custodian, which may affect the quality of execution provided by such broker. China Stock Connect restrictions could also limit the ability of a Fund to sell its China A-Shares in a timely manner, or to sell them at all. Further, different fees, costs and taxes are imposed on foreign investors acquiring China A-Shares acquired through China Stock Connect, and these fees, costs and taxes may be higher than comparable fees, costs and taxes imposed on owners of other securities providing similar investment exposure.

Event-Driven Trading Risk

A Fund may seek to profit from the occurrence of specific corporate or other events. A delay in the timing of these events, or the failure of these events to occur at all, may have a significant negative effect on a Fund’s performance.

Event-driven investing requires the Investment Manager to make predictions about (i) the likelihood that an event will occur and (ii) the impact such event will have on the value of a company’s securities. If the event fails to occur or it does not have the effect foreseen, losses can result. For example, the adoption of new business strategies, a meaningful change in management or the sale of a division or other significant assets by a company may not be valued as highly by the market as the Investment Manager had anticipated, resulting in losses. In addition, a company may announce a plan of restructuring which promises to enhance value and fail to implement it, resulting in losses to investors.

Exchange-Traded Fund (ETF) Risk

Investments in ETFs have unique characteristics, including, but not limited to, the expense structure and additional expenses associated with investing in ETFs. An ETF’s share price may not track its specified market index (if any) and may trade below its NAV. Certain ETFs use a “passive” investment strategy and do not take defensive positions in volatile or declining markets. Other ETFs in which the Fund may invest are actively managed ETFs (i.e., they do not track a particular benchmark), which indirectly subjects the Fund to active management risk. An active secondary market in an ETF’s shares may not develop or be maintained and may be halted or interrupted due to actions by its listing exchange, unusual market conditions or other reasons. There can be no assurance an ETF’s shares will continue to be listed on an active exchange. In addition, shareholders bear both their proportionate share of the Fund’s expenses and, indirectly, the ETF’s expenses, incurred through the Fund’s ownership of the ETF. Due to the expenses and costs of an underlying ETF being shared by its investors, redemptions by other investors in the ETF could result in decreased economies of scale and increased operating expenses for such ETF. These transactions might also result in higher brokerage, tax or other costs for the ETF. This risk may be particularly important when one investor owns a substantial portion of the ETF.

The Funds generally expect to purchase shares of ETFs through broker-dealers in transactions on a securities exchange, and in such cases the Funds will pay customary brokerage commissions for each purchase and sale. Shares of an ETF may also be acquired by depositing a specified portfolio of the ETF’s underlying securities, as well as a cash payment generally equal to accumulated dividends of the securities (net of expenses)

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up to the time of deposit, with the ETF’s custodian, in exchange for which the ETF will issue a quantity of new shares sometimes referred to as a “creation unit.” Similarly, shares of an ETF purchased on an exchange may be accumulated until they represent a creation unit, and the creation unit may be redeemed in kind for a portfolio of the underlying securities (based on the ETF’s NAV) together with a cash payment generally equal to accumulated dividends as of the date of redemption. A Fund may redeem creation units for the underlying securities (and any applicable cash), and may assemble a portfolio of the underlying securities (and any required cash) to purchase creation units. Each Fund’s ability to redeem creation units may be limited by the 1940 Act, which provides that ETFs, the shares of which are purchased in reliance on Section 12(d)(1)(F) of the 1940 Act, will not be obligated to redeem such shares in an amount exceeding one percent of their total outstanding securities during any period of less than 30 days.

Foreign Currency Risk

The performance of the Fund may be materially affected positively or negatively by foreign currency strength or weakness relative to the U.S. dollar, particularly if the Fund invests a significant percentage of its assets in foreign securities or other assets denominated in currencies other than the U.S. dollar. Currency rates in foreign countries may fluctuate significantly over short or long periods of time for a number of reasons, including changes in interest rates, imposition of currency controls and economic or political developments in the U.S. or abroad. The Fund may also incur currency conversion costs when converting foreign currencies into U.S. dollars and vice versa. Restrictions on currency trading may be imposed by foreign countries, which may adversely affect the value of your investment in the Fund. Even though the currencies of some countries may be pegged to the U.S. dollar, the conversion rate may be controlled by government regulation or intervention at levels significantly different than what would normally prevail in a free market. Significant revaluations of the U.S. dollar exchange rate of these currencies could cause substantial reductions in the Fund’s NAV.

Foreign Securities Risk

Investments in or exposure to securities of foreign companies involve heightened risks relative to investments in or exposure to securities of U.S. companies. For example, foreign markets can be extremely volatile. The performance of a Fund may be negatively impacted by fluctuations in a foreign currency’s strength or weakness relative to the U.S. dollar. Foreign securities may also be less liquid, making them more difficult to trade, than securities of U.S. companies so that a Fund may, at times, be unable to sell foreign securities at desirable times or prices. Brokerage commissions, custodial costs and other fees are also generally higher for foreign securities. A Fund may have limited or no legal recourse in the event of default with respect to certain foreign securities, including those issued by foreign governments. In addition, foreign governments may impose withholding or other taxes on a Fund’s income, capital gains or proceeds from the disposition of foreign securities, which could reduce the Fund’s return on such securities. In some cases such withholding or other taxes could potentially be confiscatory. Other risks include: possible delays in the settlement of transactions or in the payment of income; generally less publicly available information about foreign companies; the impact of economic, political, social, diplomatic or other conditions or events (including, for example, military confrontations and actions, war, other conflicts, terrorism, and disease/virus outbreaks and epidemics); possible seizure, expropriation or nationalization of a company or its assets or the assets of a particular investor or category of investors; possible imposition of currency exchange controls; accounting, auditing and financial reporting standards that may be less comprehensive and stringent than those applicable to domestic companies; the imposition of economic and other sanctions against a particular foreign country, its nationals or industries or businesses within the country; and the generally less stringent standard of care to which local agents may be held in the local markets. In addition, it may be difficult to obtain reliable information about the securities and business operations of certain foreign issuers. Governments or trade groups may compel local agents to hold securities in designated depositories that are not subject to independent evaluation. The less developed a country’s securities market is, the greater the level of risks. Economic sanctions may be, and have been, imposed against certain countries, organizations, companies, entities and/or individuals. Economic sanctions and other similar governmental actions could, among other things, effectively restrict or eliminate the Fund’s ability to purchase or sell securities, and thus may make the Fund’s investments in

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such securities less liquid or more difficult to value. In addition, as a result of economic sanctions, the Fund may be forced to sell or otherwise dispose of investments at inopportune times or prices, which could result in losses to the Fund and increased transaction costs. These conditions may be in place for a substantial period of time and enacted with limited advance notice to the Funds. The risks posed by sanctions against a particular foreign country, its nationals or industries or businesses within the country may be heightened to the extent a Fund invests significantly in the affected country or region or in issuers from the affected country that depend on global markets. Additionally, investments in certain countries may subject the Fund to a number of tax rules, the application of which may be uncertain. Countries may amend or revise their existing tax laws, regulations and/or procedures in the future, possibly with retroactive effect. Changes in or uncertainties regarding the laws, regulations or procedures of a country could reduce the after-tax profits of the Fund, directly or indirectly, including by reducing the after-tax profits of companies located in such countries in which the Fund invests, or result in unexpected tax liabilities for the Fund. The performance of the Fund may also be negatively affected by fluctuations in a foreign currency’s strength or weakness relative to the U.S. dollar, particularly to the extent the Fund invests a significant percentage of its assets in foreign securities or other assets denominated in currencies other than the U.S. dollar. Currency rates in foreign countries may fluctuate significantly over short or long periods of time for a number of reasons, including changes in interest rates, imposition of currency exchange controls and economic or political developments in the U.S. or abroad. The Fund may also incur currency conversion costs when converting foreign currencies into U.S. dollars and vice versa.

Operational and Settlement Risks of Foreign Securities. A Fund’s foreign securities are generally held outside the United States in the primary market for the securities in the custody of certain eligible foreign banks and trust companies (“foreign sub-custodians”), as permitted under the Investment Company Act of 1940 (the 1940 Act). Settlement practices for foreign securities may differ from those in the United States. Some countries have limited governmental oversight and regulation of industry practices, stock exchanges, depositories, registrars, brokers and listed companies, which increases the risk of corruption and fraud and the possibility of losses to a Fund. In particular, under certain circumstances, foreign securities may settle on a delayed delivery basis, meaning that a Fund may be required to make payment for securities before the Fund has actually received delivery of the securities or deliver securities prior to the receipt of payment. Typically, in these cases, a Fund will receive evidence of ownership in accordance with the generally accepted settlement practices in the local market entitling the Fund to delivery or payment at a future date, but there is a risk that the security will not be delivered to the Fund or that payment will not be received, although the Fund and its foreign sub-custodians take reasonable precautions to mitigate this risk. Losses can also result from lost, stolen or counterfeit securities; defaults by brokers and banks; failures or defects of the settlement system; or poor and improper record keeping by registrars and issuers.

Share Blocking. Share blocking refers to a practice in certain foreign markets under which an issuer’s securities are blocked from trading at the custodian or sub-custodian level for a specified number of days before and, in certain instances, after a shareholder meeting where a vote of shareholders takes place. The blocking period can last up to several weeks. Share blocking may prevent a Fund from buying or selling securities during this period, because during the time shares are blocked, trades in such securities will not settle. It may be difficult or impossible to lift blocking restrictions, with the particular requirements varying widely by country. As a consequence of these restrictions, the Investment Manager, on behalf of a Fund, may abstain from voting proxies in markets that require share blocking.

Forward Commitments on Mortgage-Backed Securities (including Dollar Rolls) Risk

When purchasing mortgage-backed securities in the “to be announced” (TBA) market (MBS TBAs), the seller agrees to deliver mortgage-backed securities for an agreed upon price on an agreed upon date, but may make no guarantee as to the specific securities to be delivered. In lieu of taking delivery of mortgage-backed securities, a Fund or a Portfolio Fund could enter into dollar rolls, which are transactions in which the Fund or the Portfolio Funds sells securities to a counterparty and simultaneously agrees to purchase those or similar securities in the future at a predetermined price. Dollar rolls involve the risk that the market value of the

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securities a Fund or a Portfolio Fund is obligated to repurchase may decline below the repurchase price, or that the counterparty may default on its obligations. These transactions may also increase a Fund’s or a Portfolio Fund’s portfolio turnover rate. If a Fund or a Portfolio Fund reinvests the proceeds of the security sold, the Fund or the Portfolio Fund will also be subject to the risk that the investments purchased with such proceeds will decline in value (a form of leverage risk). MBS TBAs and dollar rolls are subject to the risk that the counterparty to the transaction may not perform or be unable to perform in accordance with the terms of the instrument.

Frequent Trading Risk

In connection with the repositioning of the portfolio of Columbia Acorn USA to align with the May 1, 2022 changes to its principal investment strategies, the portfolio managers may more actively and frequently trade investments in the Fund’s portfolio to carry out its investment strategies than they would absent the repositioning. Frequent trading of investments increases the possibility that the Fund will realize taxable capital gains (including short-term capital gains, which are generally taxable to shareholders at higher rates than long-term capital gains for U.S. federal income tax purposes), which could reduce the Fund’s after-tax return. Frequent trading can also result in higher brokerage and other transaction costs, which could reduce the Fund’s return. The trading costs and tax effects associated with portfolio turnover may adversely affect the Fund’s performance. See About the Funds’ Investments — Portfolio Turnover for more information.

Frontier Market Risk

Frontier market countries generally have smaller economies and even less developed capital markets than typical emerging market countries (which themselves have increased investment risk relative to more developed market countries) and, as a result, a Fund’s exposure to risks associated with investing in emerging market countries are magnified when a Fund invests in frontier market countries. The increased risks include: the potential for extreme price volatility and illiquidity in frontier market countries; government ownership or control of parts of the private sector and of certain companies; trade barriers, exchange controls, managed adjustments in relative currency values and other protectionist measures imposed or negotiated by the countries with which frontier market countries trade; and the relatively new and unsettled securities laws in many frontier market countries. In addition, frontier market countries are more likely to experience instability resulting, for example, from rapid changes or developments in social, political and economic conditions. Many frontier market countries are heavily dependent on international trade, which makes them more sensitive to world commodity prices and economic downturns and other conditions in other countries. Some frontier market countries have a higher risk of currency devaluations, and some of these countries may experience periods of high inflation or rapid changes in inflation rates and may have hostile relations with other countries. Securities issued by foreign governments or companies in frontier market countries are even more likely than emerging markets securities to have greater exposure to the risks of investing in foreign securities that are described in Foreign Securities Risk.

Fund-of-Funds Risk

Determinations regarding asset classes or Portfolio Funds and a Fund’s allocations thereto may not successfully achieve a Fund’s investment objective, in whole or in part. The selected Portfolio Funds’ performance may be lower than the performance of the asset class they were selected to represent or may be lower than the performance of alternative Portfolio Funds that could have been selected to represent the asset class. A Fund also is exposed to the same risks as the Portfolio Funds in direct proportion to the allocation of its assets among the Portfolio Funds. By investing in a combination of Portfolio Funds, a Fund has exposure to the risks of many areas of the market. The ability of a Fund to realize its investment objective will depend, in large part, on the extent to which the Portfolio Funds realize their investment objectives. There is no guarantee that the Portfolio Funds will achieve their respective investment objectives. The performance of Portfolio Funds could be adversely affected if other entities that invest in the same Portfolio Funds make relatively large investments or redemptions in such Portfolio Funds. A Fund, and its shareholders, indirectly bear a portion of the expenses of any funds in which the Fund invests. Because the expenses and costs of each Portfolio Fund are shared by its

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investors, redemptions by other investors in a Portfolio Fund could result in decreased economies of scale and increased operating expenses for such fund. These transactions might also result in higher brokerage, tax or other costs for a Portfolio Fund. This risk may be particularly important when one investor owns a substantial portion of a Portfolio Fund. For certain funds-of-funds, the Investment Manager typically selects Portfolio Funds from among the funds for which it, or an affiliate, acts as the investment manager (affiliated funds) and will select an unaffiliated Portfolio Fund only if the desired investment exposure is not available through an affiliated fund. The Investment Manager has a conflict of interest in choosing affiliated funds over unaffiliated funds when selecting and investing in Portfolio Funds because the Investment Manager and/or its affiliates receive management fees from affiliated funds, and the Investment Manager has a conflict in choosing among affiliated funds when selecting and investing in Portfolio Funds, because the fees paid to the Investment Manage and/or its affiliates by certain affiliated funds are higher than the fees paid by other affiliated funds. Because of the Investment Manager’s confidence in its own strategies, investment philosophy and capacities, it will, in selecting funds, at times prefer Columbia Acorn Funds over alternative investments. There can be no assurance, however, that a Columbia Acorn Fund selected for inclusion in Columbia Thermostat Fund will, in fact, outperform similar funds managed by the Investment Manager’s affiliates. Also, to the extent that a Fund is constrained/restricted from investing (or investing further) in a particular Portfolio Fund for one or more reasons (e.g. Portfolio Fund capacity constraints or regulatory restrictions) or if a Fund chooses to sell its investment in a Portfolio Fund because of poor investment performance or for other reasons, the Fund may have to invest in another fund(s), including less desirable funds — from a strategy or investment performance standpoint — which could have a negative impact on Fund performance. In addition, Fund performance could be negatively impacted if the Investment Manager is unable to identify an appropriate alternate funds(s) in a timely manner or at all.

Fund Shares Liquidity Risk

Although the shares of Portfolio Funds that are ETFs are listed on the NYSE Arca, Inc. (the Exchange), there can be no assurance that an active, liquid or otherwise orderly trading market for shares will be established or maintained by market makers or Authorized Participants, particularly in times of stressed market conditions. (See Authorized Participant Concentration Risk above). In this regard, there is no obligation for market makers to make a market in the ETF Portfolio Fund’s shares or for Authorized Participants to submit purchase or redemption orders for creation units. Accordingly, if such parties determine not to perform their respective roles, this could, in turn, lead to variances between the market price of the ETF Portfolio Fund’s shares and the underlying value of those shares. Trading in ETF Portfolio Fund shares on the Exchange also may be disrupted or even halted due to market conditions or for reasons that, in the view of the Exchange, make trading in ETF Portfolio Fund shares inadvisable. In addition, trading in ETF Portfolio Fund shares on the Exchange may be subject to trading halts caused by extraordinary market volatility pursuant to the Exchange “circuit breaker” rules. There also can be no assurance that the requirements of the Exchange necessary to maintain the listing of the ETF Portfolio Fund’s shares will continue to be met or will remain unchanged.

Geographic Focus Risk

A Fund may be particularly susceptible to risks related to economic, political, regulatory or other events or conditions affecting issuers and countries within the specific geographic regions in which the Fund invests. Currency devaluations could occur in countries that have not yet experienced currency devaluation to date, or could continue to occur in countries that have already experienced such devaluations. As a result, a Fund’s NAV may be more volatile than the NAV of a more geographically diversified fund.

• Asia Pacific Region. A number of countries in the Asia Pacific region are considered underdeveloped or developing, including from a political, economic and/or social perspective, and may have relatively unstable governments and economies based on limited business, industries and/or natural resources or commodities. Events in any one country within the region may impact that country, other countries in the region or the region as a whole. As a result, events in the region will generally have a greater effect on the Fund than if the Fund were more geographically diversified in a region with more developed

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countries and economies. This could result in increased volatility in the value of the Fund’s investments and losses for the Fund. Continued growth of economies and securities markets in the region will require sustained economic and fiscal discipline, as well as continued commitment to governmental and regulatory reforms. Development also may be influenced by international economic conditions, including those in the United States and Japan, and by world demand for goods or natural resources produced in countries in the Asia Pacific region. Securities markets in the region are generally smaller and have a lower trading volume than those in the United States, which may result in the securities of some companies in the region being less liquid than U.S. or other foreign securities. Some currencies, inflation rates or interest rates in the Asia Pacific region are or can be volatile, and some countries in the region may restrict the flow of money in and out of the country. The risks described under Emerging Market Securities Risk and Foreign Securities Risk may be more pronounced due to the Fund’s focus on investments in the region.

• Europe. The Fund is particularly susceptible to risks related to economic, political, regulatory or other events or conditions, including acts of war or other conflicts in the region, affecting issuers and countries in Europe. Countries in Europe are often closely connected and interdependent, and events in one European country can have an adverse impact on, and potentially spread to, other European countries. Most developed countries in Western Europe are members of the EU, and many are also members of the European Economic and Monetary Union (EMU). European countries can be significantly affected by the tight fiscal and monetary controls that the EMU imposes on its members and with which candidates for EMU membership are required to comply. In addition, significant private and public sector debt problems of a single EU country can pose economic risks to the EU as a whole. Unemployment in Europe has historically been higher than in the United States and public deficits are an ongoing concern in many European countries. As a result, the Fund’s NAV may be more volatile than the NAV of a more geographically diversified fund. If securities of issuers in Europe fall out of favor, it may cause the Fund to underperform other funds that do not focus their investments in this region of the world. The UK’s departure from the EU single market became effective January 1, 2021 with the end of the Brexit transition period and the post-Brexit trade deal between the UK and EU taking effect on December 31, 2020. The impact of any partial or complete dissolution of the EU on the UK and European economies and the broader global economy could be significant, resulting in negative impacts on currency and financial markets generally, such as increased volatility and illiquidity, and potentially lower economic growth in markets in the UK, Europe and globally, which may adversely affect the value of your investment in the Fund. The impact of Brexit in the near- and long-term is still unknown and could have additional adverse effects on economies, financial markets, currencies and asset valuations around the world. Any attempt by the Fund to hedge against or otherwise protect its portfolio or to profit from such circumstances may fail and, accordingly, an investment in the Fund could lose money over short or long periods. For more information on the risks associated with Brexit, see Global Economic Risk — Brexit.

• Japan. The Japanese economy is heavily dependent upon international trade, including, among other things, the export of finished goods and the import of oil and other commodities and raw materials. Because of its trade dependence, the Japanese economy is particularly exposed to the risks of currency fluctuation, foreign trade policy and regional and global economic disruption, including the risk of increased tariffs, embargoes, and other trade limitations or factors. Strained relationships between Japan and its neighboring countries, including China, South Korea and North Korea, based on historical grievances, territorial disputes, and defense concerns, may also cause uncertainty in Japanese markets. As a result, additional tariffs, other trade barriers, or boycotts may have an adverse impact on the Japanese economy. Japanese government policy has been characterized by economic regulation, intervention, protectionism and large government deficits. The Japanese economy is also challenged by an unstable financial services sector, highly leveraged corporate balance sheets and extensive cross-ownership among major corporations. Structural social and labor market changes, including an aging workforce, population decline and traditional aversion to labor mobility may adversely affect Japan’s economic competitiveness and growth potential. The potential for natural disasters, such as

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earthquakes, volcanic eruptions, typhoons and tsunamis, could also have significant negative effects on Japan’s economy. A significant portion of Japan’s trade is conducted with developing nations in East and Southeast Asia and its economy can be affected by conditions and currency fluctuations in these and other countries. For a number of years, Japan’s economic growth rate has remained relatively low, and it may remain low in the future. Securities in Japan are denominated and quoted in yen. As a result, the value of the Fund’s Japanese securities as measured in U.S. dollars may be affected by fluctuations in the value of the Japanese yen relative to the U.S. dollar. Securities traded on Japanese stock exchanges have exhibited significant volatility in recent years. As a result of the Fund’s investment in Japanese securities, the Fund’s NAV may be more volatile than the NAV of a more geographically diversified fund. If securities of issuers in Japan fall out of favor, it may cause the Fund to underperform other funds that do not focus their investments in Japan.

Global Economic Risk

Global economies and financial markets are increasingly interconnected, which increases the possibility that conditions in one country or region might adversely impact issuers in a different country or region or across the globe. The severity or duration of adverse economic conditions may also be affected by policy changes made by governments or quasi-governmental organizations. The imposition of sanctions by the United States or another government on a country could cause disruptions to the country’s financial system and economy, which could negatively impact the value of securities.

EuroZone. A number of countries in the EU have experienced, and may continue to experience, severe economic and financial difficulties. Additional EU member countries may also fall subject to such difficulties. These events could negatively affect the value and liquidity of a Fund’s investments in euro-denominated securities and derivatives contracts, securities of issuers located in the EU or with significant exposure to EU issuers or countries. If the euro is dissolved entirely, the legal and contractual consequences for holders of euro-denominated obligations and derivative contracts would be determined by laws in effect at such time. Such investments may continue to be held, or purchased, to the extent consistent with the Fund’s investment objective and permitted under applicable law. These potential developments, or market perceptions concerning these and related issues, could adversely affect the value of your investment in the Fund.

Certain countries in the EU have had to accept assistance from supra-governmental agencies such as the International Monetary Fund, the European Stability Mechanism (the ESM) or other supra-governmental agencies. The European Central Bank has also been intervening to purchase Eurozone debt in an attempt to stabilize markets and reduce borrowing costs.

There can be no assurance that these agencies will continue to intervene or provide further assistance and markets may react adversely to any expected reduction in the financial support provided by these agencies. Responses to the financial problems by European governments, central banks and others including austerity measures and reforms, may not work, may result in social unrest and may limit future growth and economic recovery or have other unintended consequences. In addition, one or more countries may abandon the euro and/or withdraw from the EU. The impact of these actions, especially if they occur in a disorderly fashion, could be significant and far-reaching.

Brexit. The UK’s departure from the EU single market (Brexit) became effective on January 1, 2021 with the end of the Brexit transition period and the post-Brexit trade deal between the UK and EU taking effect on December 31, 2020. The impact of Brexit on the UK and European economies and the broader global economy could be significant, resulting in negative impacts on currency and financial markets generally, such as increased volatility and illiquidity, and potentially lower economic growth in markets in the UK, Europe and globally, which may adversely affect the value of your investment in the Fund.

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The UK has one of the largest economies in Europe, and member countries of the EU are substantial trading partners of the UK. The UK financial service sector continues to face uncertainty over the final relationship with the EU and globally as a result of Brexit. Brexit, certain financial services businesses may be forced to move staff and comply with two separate sets of rules or lose business to firms in Europe. The final terms of Brexit may create the potential for decreased trade, the possibility of capital outflows from the UK, devaluation of the pound sterling, the cost of higher corporate bond spreads, and the risk that all of the above factors could negatively impact business and consumer spending as well as foreign direct investment. As a result of Brexit, the British economy and its currency may be negatively impacted by changes to the UK’s economic and political relations with the EU and other countries. Any further exits from the EU by other member states, or the possibility of such exits, would likely cause additional market disruption globally and introduce new legal and regulatory uncertainties.

The impact of Brexit in the near- and long-term is still unknown and could have additional adverse effects on economies, financial markets, currencies and asset valuations around the world. Any attempt by the Fund to hedge against or otherwise protect its portfolio or to profit from such circumstances may fail and, accordingly, an investment in the Fund could lose money over short or long periods.

Growth Securities Risk

Growth securities typically trade at a higher multiple of earnings than other types of equity securities. Accordingly, the market values of growth securities may never reach their expected market value and may decline in price. In addition, growth securities, at times, may not perform as well as value securities or the stock market in general, and may be out of favor with investors for varying periods of time.

High Yield Investments Risk

Securities and other debt instruments held by a Fund that are rated below investment grade (commonly called “high yield” or “junk” bonds) and unrated debt instruments of comparable quality tend to be more sensitive to credit risk than higher-rated debt instruments and may experience greater price fluctuations in response to perceived changes in the ability of the issuing entity or obligor to pay interest and principal when due than to changes in interest rates. These investments are generally more likely to experience a default than higher-rated debt instruments. High yield debt instruments are considered to be predominantly speculative with respect to the issuer’s capacity to pay interest and repay principal. These debt instruments typically pay a premium — a higher interest rate or yield — because of the increased risk of loss, including default. High yield debt instruments may require a greater degree of judgment to establish a price, may be difficult to sell at the time and price a Fund desires, may carry high transaction costs, and also are generally less liquid than higher-rated debt instruments. The ratings provided by third party rating agencies are based on analyses by these ratings agencies of the credit quality of the debt instruments and may not take into account every risk related to whether interest or principal will be timely repaid. In adverse economic and other circumstances, issuers of lower-rated debt instruments are more likely to have difficulty making principal and interest payments than issuers of higher-rated debt instruments.

Highly Leveraged Transactions Risk

The loans or other securities in which a Fund invests may consist of transactions involving refinancings, recapitalizations, mergers and acquisitions and other financings for general corporate purposes. A Fund’s investments also may include senior obligations of a borrower issued in connection with a restructuring pursuant to Chapter 11 of the U.S. Bankruptcy Code (commonly known as “debtor-in-possession” financings), provided that such senior obligations are determined by the Investment Manager or the investment adviser to a Portfolio Fund to be a suitable investment for the Fund. In such highly leveraged transactions, the borrower assumes large amounts of debt in order to have the financial resources to attempt to achieve its business objectives. Such business objectives may include but are not limited to: management’s taking over control of a company

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(leveraged buy-out); reorganizing the assets and liabilities of a company (leveraged recapitalization); or acquiring another company. Loans or securities that are part of highly leveraged transactions involve a greater risk (including default and bankruptcy) than other investments.

Impairment of Collateral Risk

The value of collateral, if any, securing a loan can decline, and may be insufficient to meet the borrower’s obligations or difficult or costly to liquidate. In addition, a Fund’s access to collateral may be limited by bankruptcy or other insolvency laws. Further, certain floating rate and other loans may not be fully collateralized and may decline in value.

Inflation Risk

Inflation risk is the uncertainty over the future real value (after inflation) of an investment. Inflation rates may change frequently and drastically as a result of various factors, including unexpected shifts in the domestic or global economy, and a Fund’s investments may not keep pace with inflation, which may result in losses to Fund investors.

Inflation-Protected Securities Risk

Inflation-protected debt securities tend to react to changes in real interest rates. Real interest rates can be described as nominal interest rates minus the expected impact of inflation. In general, the price of an inflation-protected debt security falls when real interest rates rise, and rises when real interest rates fall. Interest payments on inflation-protected debt securities will vary as the principal and/or interest is adjusted for inflation and may be more volatile than interest paid on ordinary bonds. In periods of deflation, a Fund may have no income at all from such investments. Income earned by a shareholder depends on the amount of principal invested, and that principal will not grow with inflation unless the shareholder reinvests the portion of Fund distributions that comes from inflation adjustments. A Fund’s investment in certain inflation-protected debt securities may generate taxable income in excess of the interest they pay to the Fund, which may cause the Fund to sell investments to obtain cash to make income distributions to shareholders, including at times when it may not be advantageous to do so.

Interest Rate Risk

Interest rate risk is the risk of losses attributable to changes in interest rates. In general, if prevailing interest rates rise, the values of loans and other debt instruments tend to fall, and if interest rates fall, the values of loans and other debt instruments tend to rise. Changes in the value of a debt instrument usually will not affect the amount of income the Fund receives from it but will generally affect the value of your investment in the Fund. Changes in interest rates may also affect the liquidity of the Fund’s investments in debt instruments. In general, the longer the maturity or duration of a debt instrument, the greater its sensitivity to changes in interest rates. Interest rate declines also may increase prepayments of debt obligations, which, in turn, would increase prepayment risk (the risk that the Fund will have to reinvest the money received in securities that have lower yields). Very low or negative interest rates may impact the Fund’s yield and may increase the risk that, if followed by rising interest rates, the Fund’s performance will be negatively impacted. This risk may be particularly acute in the current market environment because market interest rates are currently near historically low levels. Thus, the Fund currently faces a heightened level of interest rate risk. The Fund is subject to the risk that the income generated by its investments may not keep pace with inflation. Actions by governments and central banking authorities can result in increases or decreases in interest rates. Higher periods of inflation could lead such authorities to raise interest rates. Such actions may negatively affect the value of debt instruments held by the Fund, resulting in a negative impact on the Fund’s performance and NAV. Debt instruments with floating coupon rates are typically less sensitive to interest rate changes, but these debt instruments may decline in value if their coupon rates do not rise as much as, or keep pace with, yields on such types of debt instruments. Because rates on certain floating rate loans and other debt instruments reset only periodically, changes in prevailing

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interest rates (and particularly sudden and significant changes) can be expected to cause fluctuations in the Fund’s NAV. Any interest rate increases could cause the value of the Fund’s investments in debt instruments to decrease. Rising interest rates may prompt redemptions from the Fund, which may force the Fund to sell investments at a time when it is not advantageous to do so, which could result in losses.

Investing in Other Funds Risk

A Fund’s investment in other funds (affiliated and/or unaffiliated funds, including exchange-traded funds (ETFs)) subjects the Fund to the investment performance (positive or negative) and risks of the Portfolio Funds or other underlying funds in direct proportion to the Fund’s investment therein. In addition, investments in ETFs have unique characteristics, including, but not limited to, the expense structure and additional expenses associated with investing in ETFs. The performance of the Portfolio Funds or other underlying funds could be adversely affected if other investors in the same Portfolio Funds or other underlying funds make relatively large investments or redemptions in such Portfolio Funds or other underlying funds. A Fund, and its shareholders, indirectly bear a portion of the expenses of any funds in which the Fund invests. Due to the expenses and costs of a fund being shared by its investors, redemptions by other investors in the Portfolio Funds or other underlying funds could result in decreased economies of scale and increased operating expenses for such fund. These transactions might also result in higher brokerage, tax or other costs for the Portfolio Funds or other underlying funds. This risk may be particularly important when one investor owns a substantial portion of the Portfolio Funds or other underlying funds. The Investment Manager has a conflict of interest in selecting affiliated funds over unaffiliated funds because the Investment Manager and/or its affiliates receives management fees from affiliated funds, and in selecting among affiliated funds, because the fees paid by certain affiliated funds are higher than the fees paid by other affiliated funds. Also, to the extent that a Fund is constrained/restricted from investing (or investing further) in a particular Portfolio Fund or other underlying fund for one or more reasons (e.g., Portfolio Fund or other underlying fund capacity constraints or regulatory restrictions) or if a Fund chooses to sell its investment in a Portfolio Fund or other underlying fund because of poor investment performance or for other reasons, the Fund may have to invest in other Portfolio Funds or other underlying funds, including less desirable funds — from a strategy or investment performance standpoint — which could have a negative impact on Fund performance. In addition, Fund performance could be negatively impacted if an appropriate alternate Portfolio Fund or other underlying fund is not identified in a timely manner or at all.

IPO Risk

IPOs are subject to many of the same risks as investing in companies with smaller market capitalizations. To the extent a Fund determines to invest in IPOs, it may not be able to invest to the extent desired, because, for example, only a small portion (if any) of the securities being offered in an IPO are available to a Fund. The investment performance of a Fund during periods when it is unable to invest significantly or at all in IPOs may be lower than during periods when the Fund is able to do so. The investment performance of a Fund during periods when it is able to invest in IPOs may not be sustainable. In addition, as a Fund increases in size, the impact of IPOs on the Fund’s performance will generally decrease. IPOs sold within 12 months of purchase may result in increased short-term capital gains, which will be taxable to a Fund’s shareholders as ordinary income.

Issuer Risk

An issuer in which a Fund invests or to which it has exposure may perform poorly or below expectations, and the value of its loans or securities may therefore decline, which may negatively affect the Fund’s performance. Underperformance of an issuer may be caused by poor management decisions, competitive pressures, breakthroughs in technology, reliance on suppliers, labor problems or shortages, corporate restructurings, fraudulent disclosures, natural disasters, military confrontations and actions, war, terrorism, disease/virus outbreaks and epidemics or other events, conditions and factors which may impair the value of an investment in the Fund.

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Large Purchases and Redemptions of Fund Shares Risk

The timing magnitude of Fund share purchases and redemptions, including by large Fund shareholders transacting in amounts of Fund shares, could prevent the Fund from being fully invested or require the Fund to sell portfolio securities at unfavorable prices or hold ready reserves of uninvested cash in amounts larger than might otherwise be the case to meet shareholder redemptions. Thus, larger Fund share purchases and redemptions could adversely impact the Fund’s performance. Such Fund share activity may also increase a Fund’s transaction costs, which would also detract from Fund performance, while also having potentially negative tax consequences to investors. A Fund, because of a large redemption, may be forced to sell its liquid or more liquid positions, resulting in the Fund holding a higher percentage of less liquid or illiquid investments (investments that a Fund reasonably expects cannot be sold or disposed of in current market conditions in seven calendar days or less without the sale or disposition significantly changing the market value of the instrument). Because the expenses and costs of a Fund are shared by its investors, large redemptions in the Fund could result in decreased economies of scale and increased operating expenses for non-redeeming Fund shareholders. In addition, in the event of a Fund proxy proposal, a large investor(s) could dictate with its/their vote the results of the proposal, which may have a less favorable impact on minority-stake shareholders. If a Fund or Portfolio Fund is forced to sell portfolio securities that have appreciated in value, such sales may accelerate the realization of taxable income.

Large-Cap Stock Risk

Investments in larger, more established companies (larger companies) may involve certain risks associated with their larger size. For instance, larger companies may be less able to respond quickly to new competitive challenges, such as changes in consumer tastes or innovation from smaller competitors. Also, large-cap companies are sometimes unable to achieve as high growth rates as successful, smaller companies, especially during extended periods of economic expansion.

Leverage Risk

Leverage occurs when a Fund increases its assets available for investment using borrowings, short sales, derivatives, or similar instruments or techniques. Use of leverage can produce volatility and may exaggerate changes in the NAV of Fund shares and in the return on the Fund’s portfolio, which may increase the risk that the Fund will lose more than it has invested. The use of leverage may cause the Fund to liquidate portfolio positions when it may not be advantageous to do so to satisfy its obligations or to meet any required asset segregation or position coverage requirements. Futures contracts, options on futures contracts, forward contracts and other derivatives can allow the Fund to obtain large investment exposures in return for meeting relatively small margin requirements. As a result, investments in those transactions may be highly leveraged. If a Fund uses leverage, through the purchase of particular instruments such as derivatives, a Fund may experience capital losses that exceed its net assets. Because short sales involve borrowing securities and then selling them, a Fund’s short sales effectively leverage the Fund’s assets. A Fund’s assets that are used as collateral to secure the Fund’s obligations to return the securities sold short may decrease in value while the short positions are outstanding, which may force the Fund to use its other assets to increase the collateral. Leverage can create an interest expense that may lower a Fund’s overall returns. Leverage presents the opportunity for increased net income and capital gains, but may also exaggerate a Fund’s volatility and risk of loss. There can be no guarantee that a leveraging strategy will be successful.

Limitations of Intraday Indicative Value (IIV) Risk

The NYSE Arca, Inc. (the Exchange) intends to disseminate the approximate per share value of the published basket of portfolio securities of Portfolio Funds that are ETFs every 15 seconds (the “intraday indicative value” or “IIV”). The IIV should not be viewed as a “real-time” update of the NAV of an ETF Portfolio Fund because (i) the IIV may not be calculated in the same manner as the NAV, which is computed once a day, generally at the end of the business day, (ii) the calculation of NAV may be subject to fair valuation

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at different prices than those used in the calculations of the IIV, (iii) unlike the calculation of NAV, the IIV does not take into account ETF Portfolio Fund expenses, and (iv) the IIV is based on the published basket of portfolio securities and not on the ETF Portfolio Fund’s actual holdings. The IIV calculations are based on local market prices and may not reflect events that occur subsequent to the local market’s close, which could affect premiums and discounts between the IIV and the market price of the ETF Portfolio Fund’s shares. For example, if the ETF Portfolio Fund fair values portfolio securities, the ETF Portfolio Fund’s NAV may deviate from the approximate per share value of the ETF Portfolio Fund’s published basket of portfolio securities (i.e., the IIV), which could result in the market prices for ETF Portfolio Fund shares deviating from NAV. The ETF Portfolio Fund, the Investment Manager and their affiliates are not involved in, or responsible for, any aspect of the calculation or dissemination of the Fund’s IIV, and the ETF Portfolio Fund, the Investment Manager and their affiliates do not make any warranty as to the accuracy of these calculations.

LIBOR Replacement Risk

The London Inter-Bank Offered Rate (LIBOR), which is used extensively in the U.S. and globally as a benchmark or reference rate for various commercial and financial contracts, among other “inter-bank offered” reference rates, is in the process of being discontinued as a global reference rate. The elimination of LIBOR may adversely affect the interest rates on, and value of, certain Fund investments that are tied to LIBOR. Such investments may include bank loans, derivatives, floating rate loans, and other assets or liabilities. On July 27, 2017, the U.K. Financial Conduct Authority (“FCA”) announced that it intended to stop compelling or inducing banks to submit LIBOR rates after 2021. The FCA and the ICE Benchmark Administration have since announced that a majority of U.S. dollar LIBOR settings will cease publication after June 30, 2023. A subset of non-U.S. dollar LIBOR settings are continuing to be published on a “synthetic” basis and it is possible that that a subset of U.S. dollar LIBOR settings will also be published after June 30, 2023 on a “synthetic” basis. Any such publications are, or would be considered, non-representative of the underlying market. The U.S. Federal Reserve, based on the recommendations of the New York Federal Reserve’s Alternative Reference Rate Committee (comprised of major derivative market participants and their regulators), has begun publishing and promoting the Secured Overnight Financing Rate (SOFR) as the alternative reference rate to LIBOR. Proposals for alternative reference rates for other currencies have also been announced or have already begun publication. Markets are slowly developing in response to these new reference rates. Uncertainty related to the liquidity impact of the change in rates, and how to appropriately adjust these rates at the time of transition, poses risks for the Fund. The effect of the discontinuation of LIBOR on the Fund will depend on, among other things, (1) existing fallback or termination provisions in individual contracts and (2) whether, how, and when industry participants develop and adopt new reference rates and fallbacks for both legacy and new instruments and contracts. The discontinuation of LIBOR could have a significant impact on the financial markets in general and may also present heightened risk to market participants, including public companies, investment advisers, investment companies, and broker-dealers. The risks associated with this discontinuation and transition will be exacerbated if the work necessary to effect an orderly transition to an alternative reference rate is not completed in a timely manner. For example, current information technology systems may be unable to accommodate new instruments and rates with features that differ from LIBOR. Accordingly, it is difficult to predict the full impact of the transition away from LIBOR on the Fund until new reference rates and fallbacks for both legacy and new products, instruments and contracts are commercially accepted and market practices become more settled.

Liquidity Risk

Liquidity risk is the risk associated with any event, circumstance, or characteristic of an investment or market that negatively impacts a Fund’s ability to sell, or realize the proceeds from the sale of, an investment at a desirable time or price. Liquidity risk may arise because of, for example, a lack of marketability of the investment. Decreases in the number of financial institutions, including banks and broker-dealers willing to make markets (match up sellers and buyers) in a Fund’s investments or decreases in their capacity or willingness to trade such investments may increase the Fund’s exposure to this risk. The debt market has experienced considerable growth, and financial institutions making markets in instruments purchased and sold by a Fund

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(e.g., bond dealers) have been subject to increased regulation. The impact of that growth and regulation on the ability and willingness of financial institutions to engage in trading or “making a market” in such instruments remains unsettled. As a result, a Fund, when seeking to sell its portfolio investments, could find that selling is more difficult than anticipated, especially during times of high market volatility. Market participants attempting to sell the same or a similar instrument at the same time as a Fund could exacerbate the Fund’s exposure to liquidity risk. A Fund may have to accept a lower selling price for the holding, sell other investments that it might otherwise prefer to hold, or forego another more appealing investment opportunity. The liquidity of Fund investments may change significantly over time and certain investments that were liquid when purchased by a Fund may later become illiquid, particularly in times of overall economic distress. Changing regulatory, market or other conditions or environments (for example, the interest rate or credit environments) may also adversely affect the liquidity and the price of a Fund’s investments. Certain types of investments, such as structured notes and non-investment grade debt instruments, as an example, may be especially subject to liquidity risk. Floating rate loans also generally are subject to legal or contractual restrictions on resale and may trade infrequently on the secondary market. The value of the loan to a Fund may be impaired in the event that the Fund needs to liquidate such loans. The inability to purchase or sell floating rate loans and other debt instruments at a fair price may have a negative impact on a Fund’s performance. Securities or other assets in which a Fund invests may be traded in the over-the-counter market rather than on an exchange and therefore may be more difficult to purchase or sell at a fair price. Judgment plays a larger role in valuing illiquid or less liquid investments as compared to valuing liquid or more liquid investments. Price volatility may be higher for illiquid or less liquid investments as a result of, for example, the relatively less frequent pricing of such securities (as compared to liquid or more liquid investments). Generally, the less liquid the market at the time a Fund sells a portfolio investment, the greater the risk of loss or decline of value to the Fund. Overall market liquidity and other factors can lead to an increase in Fund redemptions, which may negatively impact Fund performance and NAV, including, for example, if a Fund is forced to sell investments in a down market.

Governments and their regulatory agencies and self-regulatory organizations may take actions that affect the regulation of the instruments in which a Fund invests, or the issuers of such instruments, in ways that are unforeseeable. Legislation or regulation may also change the way in which a Fund or the Investment Manager, or a Portfolio Fund or its investment adviser, are regulated or supervised. Such legislation or regulation could affect or preclude a Fund’s ability to achieve its investment objective.

Governments and their regulatory agencies and self-regulatory organizations may also acquire distressed assets from financial institutions and acquire ownership interests in those institutions. The implications of government ownership and disposition of these assets are unclear, and such a program may have positive or negative effects on the liquidity, valuation and performance of a Fund’s portfolio holdings. Furthermore, volatile financial markets can expose a Fund to greater market and liquidity risk and potential difficulty in valuing portfolio instruments held by the Fund.

While the Investment Manager and the Portfolio Funds’ investment adviser can endeavor to take various preventative measures to address liquidity risk, including conducting periodic portfolio risk analysis/management and stress-testing, such measures may not be successful and may not have fully accounted for the specific circumstances that ultimately impact a Fund or Portfolio Fund and its holdings.

Listed Private Equity Fund Investment Risk

Private equity funds include financial institutions or vehicles whose principal business is to invest in and lend capital to privately held companies. A Fund or Portfolio Fund is subject to the underlying risks that affect private equity funds in which it invests, which may include increased liquidity risk (the risk that it may not be possible for the Fund to liquidate the instrument at an advantageous time or price), pricing risk (the risk that the investment may be difficult to value), sector risk (the risk that a significant portion of Fund assets invested in one or more economic sectors may make the Fund more vulnerable to unfavorable developments in that sector than funds that invest more broadly) and credit risk (the risk that the issuer of a debt instrument will default or

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otherwise become unable, or be perceived to be unable or unwilling, to honor a financial obligation, such as making payments to the Fund when due). Limited or incomplete information about the companies in which private equity funds invest, and relatively concentrated investment portfolios of private equity funds, may expose the Fund or Portfolio Fund to greater volatility and risk of loss. A Fund or Portfolio Fund investment in private equity funds subjects Fund shareholders indirectly to the fees and expenses incurred by private equity funds.

Macro Strategy Risk

The profitability of any macro program depends primarily on the ability of its manager to predict derivative contract price movements to implement investment ideas regarding macroeconomic trends. Price movements for commodity interests are influenced by, among other things: changes in interest rates; governmental, agricultural, trade, fiscal, monetary and exchange control programs and policies; weather and climate conditions; natural disasters, such as hurricanes; changing supply and demand relationships; changes in balances of payments and trade; U.S. and international rates of inflation and deflation; currency devaluations and revaluations; U.S. and international political and economic events; and changes in philosophies and emotions of market participants. The manager’s trading methods may not take all of these factors into account.

The global macro programs to which a Fund’s investments are exposed typically use derivative financial instruments that are actively traded using a variety of strategies and investment techniques that involve significant risks. The derivative financial instruments traded include commodities, currencies, futures, options and forward contracts and other derivative instruments that have inherent leverage and price volatility that result in greater risk than instruments used by typical mutual funds, and the systematic programs used to trade them may rely on proprietary investment strategies that are not fully disclosed, which may in turn result in risks that are not anticipated.

Market Price Relative to NAV Risk

Shares of Portfolio Funds that are ETFs may trade at prices that vary from the Fund’s NAV. Shares of ETF Portfolio Funds are listed for trading on NYSE Arca, Inc. (the Exchange) and are bought and sold in the secondary market at market prices that may differ, in some cases significantly, from their NAV. The NAV of an ETF Portfolio Fund will generally fluctuate with changes in the market value of the ETF Portfolio Fund’s holdings. The market prices of shares, however, will generally fluctuate in response to changes in NAV, as well as the relative supply of, and demand for, ETF Portfolio Fund shares on the Exchange. The Investment Manager and its affiliates cannot predict whether ETF Portfolio Fund shares will trade below, at or above their NAV. Price differences may result because of, among other factors, supply and demand forces in the secondary trading market for ETF Portfolio Fund shares. It is expected that these forces generally will be closely related to, but not identical to, the same forces influencing the prices of the ETF Portfolio Fund’s holdings. In this connection, if a shareholder purchases ETF Portfolio Fund shares at a time when the market price is at a premium to the NAV or sells shares at a time when the market price is at a discount to the NAV, the shareholder may sustain losses. Different investment strategies or techniques, including those intended to be defensive in nature, including, as examples, stop loss orders to sell an ETF Portfolio Fund’s shares in the secondary market during negative market events or conditions, such as a “flash crash” or other market disruptions may not work as intended and may produce significant losses to investors. Investors should consult their financial intermediary prior to using any such investment strategies or techniques, or before investing in an ETF.

Market Risk

The Fund may incur losses due to declines in the value of one or more securities in which it invests. These declines may be due to factors affecting a particular issuer, or the result of, among other things, political, regulatory, market, economic or social developments affecting the relevant market(s) more generally. In addition, turbulence in financial markets and reduced liquidity in equity, credit and/or fixed income markets may negatively affect many issuers, which could adversely affect the Fund’s ability to price or value hard-to-value assets in thinly traded and closed markets and could cause significant redemptions and operational challenges. Global economies and financial markets are increasingly interconnected, and conditions and events in one country, region or financial market may

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adversely impact issuers in a different country, region or financial market. These risks may be magnified if certain events or developments adversely interrupt the global supply chain; in these and other circumstances, such risks might affect companies worldwide. As a result, local, regional or global events such as terrorism, war, other conflicts, natural disasters, disease/virus outbreaks and epidemics or other public health issues, recessions, depressions or other events — or the potential for such events — could have a significant negative impact on global economic and market conditions. In addition, as the share of assets invested in passive index-based strategies increases, price correlations among the securities included in an index may increase and the market value of securities, including those included in one or more market indices, may become less correlated with their underlying values. Because index-based strategies generally buy or sell securities based solely on their inclusion in an index, securities prices may rise or fall based on whether money is flowing into or out of these strategies rather than based on an analysis of the securities’ underlying values. This valuation disparity could lead to increased price volatility for individual securities, and the market as a whole, which may result in Fund losses.

The large-scale invasion of Ukraine by Russia in February 2022 has resulted in sanctions and market disruptions including declines in regional and global stock and commodity markets and significant devaluations of Russian currency. The extent and duration of the military action are impossible to predict but could be significant. Market disruption caused by the Russian military action, and any counter measures or responses thereto (including international sanctions, a downgrade in the country’s credit rating, purchasing and financing restrictions, boycotts, tariffs, changes in consumer or purchaser preferences, cyberattacks and espionage) could have severe adverse impacts on regional and/or global securities and commodities markets, including markets for oil and natural gas. These impacts may include reduced market liquidity, distress in credit markets, further disruption of global supply chains, increased risk of inflation, and limited access to investments in certain international markets and/or issuers. These developments and other related events could negatively impact Fund performance.

The pandemic caused by coronavirus disease 2019 and its variants (COVID-19) has resulted in, and may continue to result in, significant global economic and societal disruption and market volatility due to disruptions in market access, resource availability, facilities operations, imposition of tariffs, export controls and supply chain disruption, among others. Such disruptions may be caused, or exacerbated by, quarantines and travel restrictions, workforce displacement and loss in human and other resources. The uncertainty surrounding the magnitude, duration, reach, costs and effects of the global pandemic, as well as actions that have been or could be taken by governmental authorities or other third parties, present unknowns that are yet to unfold. The impacts, as well as the uncertainty over impacts to come, of COVID-19 — and any other infectious illness outbreaks, epidemics and pandemics that may arise in the future — could negatively affect global economies and markets in ways that cannot necessarily be foreseen. In addition, the impact of infectious illness outbreaks and epidemics in emerging market countries may be greater due to generally less established healthcare systems, governments and financial markets. Public health crises caused by the COVID-19 outbreak may exacerbate other pre-existing political, social and economic risks in certain countries or globally. The disruptions caused by COVID-19 could prevent the Fund from executing advantageous investment decisions in a timely manner and negatively impact the Fund’s ability to achieve its investment objective. Any such event(s) could have a significant adverse impact on the value and risk profile of the Fund.

Master Limited Partnership Risk

Investments in securities (units) of master limited partnerships involve risks that differ from an investment in common stock. Holders of these units have more limited rights to vote on matters affecting the partnership. These units may be subject to cash flow and dilution risks. There are also certain tax risks associated with such an investment. In particular, a Fund’s investment in master limited partnerships can be limited by the Fund’s intention to qualify as a regulated investment company for U.S. federal income tax purposes, and can limit the Fund’s ability to so qualify. In addition, conflicts of interest may exist between common unit holders, subordinated unit holders and the general partner of a master limited partnership, including a conflict arising as a result of incentive distribution payments. In addition, there are risks related to the general partner’s right to require unit holders to sell their common units at an undesirable time or price.

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Mid-Cap Company Securities Risk

Securities of mid-capitalization companies (mid-cap companies) can, in certain circumstances, have more risk than securities of larger capitalization companies (larger companies). For example, mid-cap companies may be more vulnerable to market downturns and adverse business or economic events than larger companies because they may have more limited financial resources and business operations. Mid-cap companies are also more likely than larger companies to have more limited product lines and operating histories and to depend on smaller and generally less experienced management teams. Securities of mid-cap companies may trade less frequently and in smaller volumes and may fluctuate more sharply in value than securities of larger companies. When a Fund takes significant positions in mid-cap companies with limited trading volumes, the liquidation of those positions, particularly in a distressed market, could be difficult and result in Fund investment losses that would affect the value of your investment in the Fund. In addition, some mid-cap companies may not be widely followed by the investment community, which can lower the demand for their stocks.

Money Market Fund Investment Risk

Certain money market funds in which the Funds may invest, including certain money market mutual funds managed by Columbia Management, must calculate their NAV to the nearest 0.01%, which produces fluctuations in the shares’ value in response to small changes in market values. Because the share price of these money market funds will fluctuate, when a Fund sells its shares they may be worth more or less than what the Fund originally paid for them. A Fund could also lose money if the money market fund holds defaulted securities or as a result of adverse market conditions. These money market funds may impose a fee (“liquidity fee”) upon the redemption of their shares or may temporarily suspend the ability to redeem shares if the money market fund’s liquidity falls below required minimums because of market conditions or other factors.

These measures may result in an investment loss or prohibit the Fund from redeeming shares when the Investment Manager would otherwise redeem shares. If a liquidity fee is imposed or redemptions are suspended, an investing Fund may have to sell other investments at less than opportune times to raise cash to meet shareholder redemptions or for other purposes. The Investment Manager, as a result of imposition of liquidity fees or suspension of redemptions, or the potential risk of such actions, may determine to not invest the Funds’ assets in a money market fund when it otherwise would, and may potentially be forced to invest in more expensive, lower-performing investments.

Imposition of a liquidity fee or temporary suspension of redemption is at the discretion of a money market fund’s board of directors or trustees; however, they must impose a liquidity fee or suspend redemptions if they determine it would be in the best interest of the money market fund. Such a determination may conflict with the interest of the Funds. In the case of affiliated money market funds managed or sponsored by Columbia Management, the Investment Manager may also face a conflict of interest between recommending imposition of a liquidity fee or suspension of redemptions and continuing to maintain unrestricted liquidity for the investing Funds. In such circumstances, federal regulations require the board and Columbia Management, and the Investment Manager to act in the best interest of the money market funds rather than the Funds, which could adversely affect the Funds.

Funds may also invest in money market funds that invest at least 99.5% of their assets in U.S. government securities (“government money market funds”). Government money market funds may seek to maintain a stable price of $1.00 per share and are generally not permitted to impose liquidity fees or temporarily suspend redemptions. However, government money market funds typically offer materially lower yields than other money market funds with fluctuating share prices.

A Fund could lose money invested in a government money market fund. An investment in a money market fund, including a government money market fund, is not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency. A money market fund’s sponsor has no legal obligation to

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provide financial support to the money market fund, and you should not expect that the sponsor or any person will provide financial support to a money market fund at any time.

In addition to the fees and expenses that the Fund directly bears, the Fund indirectly bears the fees and expenses of any money market funds in which it invests, including affiliated money market funds. To the extent these fees and expenses, along with the fees and expenses of any other funds in which the Fund may invest, are expected to equal or exceed 0.01% of the Fund’s average daily net assets, they will be reflected in the Annual Fund Operating Expenses set forth in the table under “Fees and Expenses of the Fund.” By investing in a money market fund, a Fund will be exposed to the investment risks of the money market fund in direct proportion to such investment. The money market fund may not achieve its investment objective. The Fund, through its investment in the money market fund, may not achieve its investment objective. To the extent the Fund invests in instruments such as derivatives, the Fund may hold investments, which may be significant, in money market fund shares to cover its obligations resulting from the Fund’s investments in derivatives. Money market funds are subject to comprehensive regulations. The enactment of new legislation or regulations, as well as changes in interpretation and enforcement of current laws, may affect the manner of operation, performance and/or yield of money market funds.

Mortgage- and Other Asset-Backed Securities Risk

The value of any mortgage-backed and other asset-backed securities, including collateralized debt obligations and collateralized loan obligations, if any, held by a Fund or a Portfolio Fund may be affected by, among other things, changes or perceived changes in: interest rates; factors concerning the interests in and structure of the issuer or the originator of the mortgages or other assets; the creditworthiness of the entities that provide any supporting letters of credit, surety bonds or other credit enhancements; or the market’s assessment of the quality of underlying assets. Mortgage-backed securities represent interests in, or are backed by, pools of mortgages from which payments of interest and principal (net of fees paid to the issuer or guarantor of the securities) are distributed to the holders of the mortgage-backed securities. Other types of asset-backed securities typically represent interests in, or are backed by, pools of receivables such as credit, automobile, student and home equity loans. Mortgage- and other asset-backed securities can have a fixed or an adjustable rate. Mortgage- and other asset-backed securities are subject to liquidity risk (the risk that it may not be possible for the Fund to liquidate the instrument at an advantageous time or price) and prepayment risk (the risk that the underlying mortgage or other asset may be refinanced or prepaid prior to maturity during periods of declining or low interest rates, causing a Fund or a Portfolio Fund to have to reinvest the money received in securities that have lower yields). In addition, the impact of prepayments on the value of mortgage- and other asset-backed securities may be difficult to predict and may result in greater volatility. A decline or flattening of housing values may cause delinquencies in mortgages (especially sub-prime or non-prime mortgages) underlying mortgage-backed securities and thereby adversely affect the ability of the mortgage-backed securities issuer to make principal and/or interest payments to mortgage-backed securities holders, including the Fund. Rising or high interest rates tend to extend the duration of mortgage- and other asset-backed securities, making them more volatile and more sensitive to changes in interest rates. Payment of principal and interest on some mortgage-backed securities (but not the market value of the securities themselves) may be guaranteed (i) by the full faith and credit of the U.S. Government (in the case of securities guaranteed by the Government National Mortgage Association) or (ii) by its agencies, authorities, enterprises or instrumentalities (in the case of securities guaranteed by the Federal National Mortgage Association (FNMA) or the Federal Home Loan Mortgage Corporation (FHLMC)), which are not insured or guaranteed by the U.S. Government (although FNMA and FHLMC may be able to access capital from the U.S. Treasury to meet their obligations under such securities). Mortgage-backed securities issued by non-governmental issuers (such as commercial banks, savings and loan institutions, private mortgage insurance companies, mortgage bankers and other secondary market issuers) may be supported by various credit enhancements, such as pool insurance, guarantees issued by governmental entities, letters of credit from a bank or senior/subordinated structures, and may entail greater risk than obligations guaranteed by the U.S. Government, whether or not such obligations are guaranteed by the private issuer. Under the direction of the Federal Housing Finance Agency, FNMA and FHLMC have entered into a joint initiative to develop a common

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securitization platform for the issuance of a uniform mortgage-backed security (the “Single Security Initiative”) that aligns the characteristics of FNMA and FHLMC certificates. The Single Security Initiative was implemented in June 2019, and the effects it may have on the market for mortgage-backed securities are uncertain.

Municipal Securities Risk

Municipal securities are debt obligations generally issued to obtain funds for various public purposes, including general financing for state and local governments, or financing for a specific project or public facility, and include obligations of the governments of the U.S. territories, commonwealths and possessions such as Guam, Puerto Rico and the U.S. Virgin Islands to the extent such obligations are exempt from state and federal U.S. income taxes. The value of municipal securities can be significantly affected by actual or expected political and legislative changes at the federal or state level. Municipal securities may be fully or partially backed by the taxing authority of the local government, by the credit of a private issuer, by the current or anticipated revenues from a specific project or specific assets or by domestic or foreign entities providing credit support, such as letters of credit, guarantees or insurance, and are generally classified into general obligation bonds and special revenue obligations. General obligation bonds are backed by an issuer’s taxing authority and may be vulnerable to limits on a government’s power or ability to raise revenue or increase taxes. They may also depend for payment on legislative appropriation and/or funding or other support from other governmental bodies. Revenue obligations are payable from revenues generated by a particular project or other revenue source, and are typically subject to greater risk of default than general obligation bonds because investors can look only to the revenue generated by the project or other revenue source backing the project, rather than to the general taxing authority of the state or local government issuer of the obligations. Because many municipal securities are issued to finance projects in sectors such as education, health care, transportation and utilities, conditions in those sectors can affect the overall municipal market. The amount of publicly available information for municipal issuers is generally less than for corporate issuers.

Issuers in a state, territory, commonwealth or possession in which a Fund or a Portfolio Fund invests have experienced significant financial difficulties for various reasons, including as the result of events that cannot be reasonably anticipated or controlled such as economic downturns or similar periods of economic stress, social conflict or unrest, labor disruption and natural disasters. Such financial difficulties may lead to a credit rating downgrades or defaults of such issuers which, in turn, could affect the market values and marketability of many or all municipal obligations of issuers in such state, territory, commonwealth or possession. For example, the COVID-19 pandemic has significantly stressed the financial resources of many municipal issuers, which may impair a municipal issuer’s ability to meet its financial obligations when due and could adversely impact the value of its bonds, which could negatively impact the performance of the Fund. Securities issued by Puerto Rico and its agencies and instrumentalities have been subject to multiple credit downgrades as a result of Puerto Rico’s ongoing fiscal challenges and uncertainty about its ability to make full repayment on these obligations. These challenges and uncertainties have been exacerbated by hurricanes Maria and Irma, earthquakes in 2019, and the resulting natural disasters in Puerto Rico. In June 2019, a $19 billion presidental disaster relief bill allocated approximately $1 billion to Puerto Rico. Additionally, recent statements by government officials regarding management of the recovery burden may increase price volatility and the risk that Puerto Rican municipal securities held by the Fund will lose value. Even prior to the recent natural disasters, certain issuers of Puerto Rican municipal securities had failed to make payments on obligations when due, and additional missed payments or defaults are likely to occur in the future. In May 2017, Puerto Rico filed in U.S. federal court to commence a debt restructuring process similar to that of a traditional municipal bankruptcy under a new federal law for insolvent U.S. territories, called Promesa, which, among other things, established the Financial and Oversight Management Board (FOMB) to oversee Puerto Rico’s financial operations and provide a legal framework for debt restructuring. Puerto Rico’s case will be the first ever heard under Promesa for which there is no existing body of court precedent. Accordingly, Puerto Rico’s debt restructuring process could take significantly longer than recent municipal bankruptcy proceedings adjudicated pursuant to Chapter 9 of the U.S. Bankruptcy Code. In addition to the debt restructuring petition filed on behalf of Puerto Rico, in May 2017, FOMB separately filed debt restructuring petitions for certain Puerto Rico instrumentalities, including the Puerto Rico Highways and Transportation Authority, Puerto Rico Sales Tax

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Financing Corporation (COFINA), Puerto Rico Electric and Power Authority and Employee Retirement System. On February 4, 2019, the United District Court for the District of Puerto Rico approved a plan to restructure $17.6 billion of COFINA-issued debt. On May 2, 2019, FOMB filed adversary proceedings to avoid clawback payments made to certain bondholders. In February 2020, the FOMB announced a new consensual agreement with roughly 50% of Puerto Rico’s General Obligation (GO) and Public Building Authority (PBA) bondholders. The agreement significantly reduces debt service by cutting $35 billion of liabilities to just $10.7 billion. Pursuant to the agreement, GO and PBA bondholders would receive recoveries ranging from 65% to 75% based on a consideration of $10.1 billion in new bonds and $3.4 billion in cash. Due to the impact of COVID-19, FOMB is expected to propose an amended version of the plan in February 2021. It is not clear whether additional debt restructuring processes will ultimately be approved or, if so, the extent to which they will apply to Puerto Rico municipal securities sold by an issuer other than the Commonwealth. Further legislation by the U.S. Congress, actions by the FOMB, or court approval of a debt restructuring could reduce the principal amount due, the interest rate, the maturity and other terms of Puerto Rico municipal securities, which could adversely affect the value of Puerto Rico municipal securities. The value of a Fund’s shares will be negatively impacted to the extent it invests in such securities. A Fund’s annual and semiannual reports show the Fund’s investment exposures at a point in time. The risk of investing in a Fund is directly correlated to the Fund’s investment exposures.

A Fund’s or a Portfolio Fund’s investments in municipal securities may include securities of issuers in the health care sector, which subjects the Fund’s or the Portfolio Fund’s investments to the risks associated with that sector, including the risk of regulatory action or policy changes by numerous governmental agencies and bodies, including federal, state, and local governmental agencies, as well as requirements imposed by private entities, such as insurance companies. A major source of revenue for the health care industry is payments from the Medicare and Medicaid programs. As a result, the industry is sensitive to legislative changes and reductions in governmental spending for such programs. Numerous other factors may affect the industry, such as general and local economic conditions, demand for services, expenses (including, among others, malpractice insurance premiums) and competition among health care providers. Additional factors also may adversely affect health care facility operations, such as adoption of legislation proposing a national health insurance program, other state or local health care reform measures, medical and technological advances that alter the need for or cost of health services or the way in which such services are delivered, changes in medical coverage that alter the traditional fee-for-service revenue stream, and efforts by employers, insurers, and governmental agencies to reduce the costs of health insurance and health care services.

A Fund’s or Portfolio Fund’s investments in municipal securities may include transportation-related municipal bonds which may be used to finance projects including construction, maintenance and operations of non-toll and toll-backed roads, bridges, tunnels, railways, airports, seaports and other transportation systems. Transportation-related municipal bonds may be fully or partially backed by taxes, fees, tolls, or other sources of revenue. Investment in transportation-related municipal bonds may subject the Fund or Portfolio Fund to the certain risks, including, but not limited to, the risk of insufficient or declining revenues from the sources backing the bonds, contractor non-performance or underperformance and unexpectedly higher construction, fuel or other costs.

Opportunistic Investing Risk

Undervalued securities involve the risk that they may never reach their expected full market value, either because the market fails to recognize the security’s intrinsic worth or the expected value was misgauged. Undervalued securities also may decline in price even though the Investment Manager believes they are already undervalued. Turnaround companies may never improve their fundamentals, may take much longer than expected to improve, or may improve much less than expected. Development stage companies could fail to develop and deplete their assets, resulting in large percentage losses.

Preferred Stock Risk

Preferred stock is a type of stock that may pay dividends at a different rate than common stock of the same issuer, if at all, and that has preference over common stock in the payment of dividends and the liquidation of

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assets. Preferred stock does not ordinarily carry voting rights. The price of a preferred stock is generally determined by earnings, type of products or services, projected growth rates, experience of management, liquidity, and general market conditions of the markets on which the stock trades. The most significant risks associated with investments in preferred stock include issuer risk, market risk and interest rate risk (the risk of losses attributable to changes in interest rates).

Prepayment and Extension Risk

Prepayment and extension risk is the risk that a loan, bond or other security or investment might, in the case of prepayment risk, be called or otherwise converted, prepaid or redeemed before maturity, and, in the case of extension risk, that the investment might not be called as expected. In the case of prepayment risk, if the investment is converted, prepaid or redeemed before maturity, the Investment Manager or the investment adviser to a Portfolio Fund may not be able to invest the proceeds in other investments providing as high a level of income, resulting in a reduced yield to a Fund. In the case of mortgage- or other asset-backed securities, as interest rates decrease or spreads narrow, the likelihood of prepayment increases. Conversely, extension risk is the risk that an unexpected rise in interest rates will extend the life of a mortgage- or asset-backed security beyond the prepayment time. If a Fund’s investments are locked in at a lower interest rate for a longer period of time, the Investment Manager or a Portfolio Fund’s investment adviser may be unable to capitalize on securities with higher interest rates or wider spreads.

Private Investments in Public Equity (PIPEs) Risk

PIPEs are equity securities purchased in a private placement that are issued by issuers who have outstanding, publicly traded equity securities of the same class. Shares in PIPEs are not registered with the SEC and may not be sold unless registered with the SEC or pursuant to an exemption from registration. This restricted period can last many months. Until the public registration process is completed, the resale of the PIPE shares are restricted and the Fund may sell the shares after six months, with certain restrictions, if the Fund is not an affiliate of the issuer (under relevant securities law, a holder of restricted shares may sell the shares after 6 months if the holder is not affiliated to the issuer). Generally, such restrictions cause the PIPEs to be illiquid during this time. If the issuer does not agree to register the PIPE shares, the shares will remain restricted, not be freely tradable and may only be sold pursuant to an exemption from registration. Even if the PIPE shares are registered for resale, there is no assurance that the registration will be in effect at the time the Fund elects to sell the shares.

Qualified Financial Contracts Risk

Qualified financial contracts include agreements relating to swaps, currency forwards and other derivatives as well as repurchase agreements and securities lending agreements. Beginning in 2019, regulations adopted by prudential regulators require that certain qualified financial contracts entered into with certain counterparties that are part of a U.S. or foreign banking organization designated as a global-systemically important banking organization to include contractual provisions that delay or restrict the rights of counterparties, such as the Funds, to exercise certain close-out, cross-default and similar rights under certain conditions. Qualified financial contracts are subject to a stay for a specified time period during which counterparties, such as the Funds, will be prevented from closing out a qualified financial contract if the counterparty is subject to resolution proceedings and prohibit the Funds from exercising default rights due to a receivership or similar proceeding of an affiliate of the counterparty. Implementation of these requirements may increase credit and other risks to the Funds.

Real Estate-Related Investment Risk

Investments in real estate investment trusts (REITs) and in securities of other companies (wherever organized) principally engaged in the real estate industry subject a Fund to, among other things, risks similar to those of direct investments in real estate and the real estate industry in general. These include risks related to

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general and local economic conditions, possible lack of availability of financing and changes in interest rates or property values. REITs are entities that either own properties or make construction or mortgage loans, and also may include operating or finance companies. The value of interests in a REIT may be affected by, among other factors, changes in the value of the underlying properties owned by the REIT, changes in the prospect for earnings and/or cash flow growth of the REIT itself, defaults by borrowers or tenants, market saturation, decreases in market rates for rents, and other economic, political, or regulatory matters affecting the real estate industry, including REITs. REITs and similar non-U.S. entities depend upon specialized management skills, may have limited financial resources, may have less trading volume in their securities, and may be subject to more abrupt or erratic price movements than the overall securities markets. REITs are also subject to the risk of failing to qualify for favorable tax treatment under the Internal Revenue Code of 1986, as amended. The failure of a REIT to continue to qualify as a REIT for tax purposes can materially and adversely affect its value. Some REITs (especially mortgage REITs) are affected by risks similar to those associated with investments in debt securities including changes in interest rates and the quality of credit extended.

Regulatory Risk — Alternative Investments

Legal, tax, and regulatory developments may adversely affect a Portfolio Fund that is an ETF and its investments. The regulatory environment for an ETF Portfolio Fund and certain of its investments is evolving, and changes in the regulation of investment funds, their managers, and their trading activities and capital markets, or a regulator’s disagreement with the ETF Portfolio Fund’s or others’ interpretation of the application of certain regulations, may adversely affect the ability of the ETF Portfolio Fund to pursue its investment strategy, its ability to obtain leverage and financing, and the value of investments held by the ETF Portfolio Fund. There has been an increase in governmental, as well as self-regulatory, scrutiny of the investment industry in general and the alternative investment industry in particular. It is impossible to predict what, if any, changes in regulations may occur, but any regulation that restricts the ability of an ETF Portfolio Fund or any underlying funds or other investments to trade in securities or other instruments or the ability of the ETF Portfolio Fund or underlying funds to employ, or brokers and other counterparties to extend, credit in their trading (as well as other regulatory changes that result) could have a material adverse impact on the ETF Portfolio Fund’s performance.

Shareholders should understand that the business of an ETF Portfolio Fund is dynamic and is expected to change over time. Therefore, an ETF Portfolio Fund and its underlying investments may be subject to new or additional regulatory constraints in the future. Such regulations may have a significant impact on shareholders or the operations of the ETF Portfolio Fund, including, without limitation, restricting the types of investments the ETF Portfolio Fund may make, preventing the ETF Portfolio Fund from exercising its voting rights with regard to certain financial instruments, requiring the ETF Portfolio Fund to disclose the identity of its investors or otherwise. To the extent the ETF Portfolio Fund or its underlying investments are subject to such regulation, such regulations may have a detrimental effect on one or more shareholders. Prospective investors are encouraged to consult their own advisors regarding an investment in an ETF.

Regulatory Risk — U.S. Banking Law

Following the conversion of Ameriprise National Trust Bank into a federal savings bank in May 2019, Ameriprise Financial continues to be subject to ongoing supervision by the Board of Governors for the Federal Reserve System (“FRB”) as well as applicable U.S. federal banking laws, including the Home Owners Loan Act and certain parts of the Bank Holding Company Act, including Section 13 thereof (commonly referred to as the Volcker Rule). These laws impose limits on the amount and duration of any proprietary capital held in the Fund by the Investment Manager, Ameriprise Financial or certain of their controlled affiliates or products. Failure to comply with those limitations could subject the Fund to limitations on its portfolio investments and/or trading restrictions which could adversely impact the Fund’s ability to execute its investment strategy. Under such circumstances, the Investment Manager and/or its affiliates may be required to reduce their ownership interests in the Fund or the Fund’s Board may liquidate the Fund, which may result in losses, increased transaction costs and/or adverse tax consequences for the Fund, each of which may adversely affect the value of your investment in the Fund.

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Reinvestment Risk

Reinvestment risk arises when a Fund is unable to reinvest income or principal at the same or at least the same return it is currently earning.

Repurchase Agreements Risk

Repurchase agreements are agreements in which the seller of a security to a Fund agrees to repurchase that security from the Fund at a mutually agreed upon price and time. Repurchase agreements carry the risk that the counterparty may not fulfill its obligations under the agreement. This could cause a Fund’s income and the value of your investment in the Fund to decline.

Reverse Repurchase Agreements Risk

Reverse repurchase agreements are agreements in which a Fund sells a security to a counterparty, such as a bank or broker-dealer, in return for cash and agrees to repurchase that security at a mutually agreed upon price and time. Reverse repurchase agreements carry the risk that the market value of the security sold by a Fund may decline below the price at which the Fund must repurchase the security. Reverse repurchase agreements also may be viewed as a form of borrowing, and borrowed assets used for investment creates leverage risk (the risk that losses may be greater than the amount invested). Leverage can create an interest expense that may lower a Fund’s overall returns. Leverage presents the opportunity for increased net income and capital gains, but may also exaggerate a Fund’s volatility and risk of loss. There can be no guarantee that this strategy will be successful.

Rule 144A and Other Exempted Securities Risk

A Fund may invest in privately placed “Rule 144A” and other securities or instruments exempt from SEC registration (collectively, “private placements”) that are determined to be liquid in accordance with procedures adopted by the Board. In the U.S. market, private placements are typically sold only to qualified institutional buyers, or qualified purchasers, as applicable. An insufficient number of buyers interested in purchasing private placements at a particular time could adversely affect the marketability of such investments and a Fund might be unable to dispose of them promptly or at reasonable prices, subjecting the Fund to liquidity risk (the risk that it may not be possible for the Fund to liquidate the instrument at an advantageous time or price). A Fund’s holdings of private placements may increase the level of Fund illiquidity if eligible buyers are unable or unwilling to purchase them at a particular time. A Fund may also have to bear the expense of registering the securities for resale and the risk of substantial delays in effecting the registration. Additionally, the purchase price and subsequent valuation of private placements typically reflect a discount, which may be significant, from the market price of comparable securities for which a more liquid market exists. Issuers of Rule 144A eligible securities are required to furnish information to potential investors upon request. However, the required disclosure is much less extensive than that required of public companies and is not publicly available since the offering information is not filed with the SEC. Further, issuers of Rule 144A eligible securities can require recipients of the offering information (such as a Fund) to agree contractually to keep the information confidential, which could also adversely affect a Fund’s ability to dispose of the security.

Secondary Market Trading Risk

Investors buying or selling shares a Portfolio Fund that is an ETF will pay brokerage commissions or other charges imposed by brokers as determined by that broker. Brokerage commissions are often a fixed amount and may be a significant proportional cost for investors seeking to buy or sell relatively small amounts of shares. In addition, secondary market investors will also incur the cost of the difference between the price that an investor is willing to pay for ETF Portfolio Fund shares (the bid price) and the price at which an investor is willing to sell ETF Portfolio Fund shares (the ask price). This difference in bid and ask prices is often referred to as the “spread” or “bid/ask spread.” The bid/ask spread varies over time for ETF Portfolio Fund shares based on trading

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volume and market liquidity, and is generally lower if the ETF Portfolio Fund’s shares have more trading volume and market liquidity and higher if the ETF Portfolio Fund’s shares have little trading volume and market liquidity. Further, increased market volatility may cause increased bid/ask spreads.

Sector Risk

At times, a Fund may have a significant portion of its assets invested in securities of companies conducting business within one or more economic sectors. Companies in the same sector may be similarly affected by economic, regulatory, political or market events or conditions, which may make a Fund more vulnerable to unfavorable developments in that sector than funds that invest more broadly. Generally, the more broadly a Fund invests, the more it spreads risk and potentially reduces the risks of loss and volatility.

Sector Risk — Consumer Discretionary/Staples Sector Investments. To the extent a Fund concentrates its investments in companies in the consumer discretionary and staples sectors, it is more susceptible to the particular risks that may affect companies in that sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the consumer discretionary and staples sectors are subject to certain risks, including fluctuations in the performance of the overall domestic and international economy, interest rate changes, currency exchange rates, increased competition and consumer confidence. Performance of such companies may be affected by factors including reduced disposable household income, reduced consumer spending, and changing demographics and consumer tastes. Companies in these sectors may be subject to competitive forces (including competition brought by an influx of foreign brands), which may also have an adverse impact on their profitability. These sectors may be strongly affected by fads, marketing campaigns, changes in demographics and consumer preferences, and other economic or social factors affecting consumer demand. Governmental regulation, including price controls and regulations on packaging, labeling, competition, and certification, may affect the profitability of certain companies invested in by the Fund. Companies operating in these sectors may also be adversely affected by government and private litigation.

Sector Risk — Energy Sector Investments. To the extent a Fund concentrates its investments in companies in the energy sector, it is more susceptible to the particular risks that may affect companies in that sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the energy sector are subject to certain risks, including legislative or regulatory changes, adverse market conditions and increased competition. Performance of such companies may be affected by factors including, among others, fluctuations in energy prices, energy fuel supply and demand factors, energy conservation, the success of exploration projects, local and international policies, and events occurring in nature. For instance, natural events (such as earthquakes, hurricanes or fires in prime natural resources areas) and political events (such as government instability or military confrontations or actions) can affect the value of companies involved in business activities in the energy sector. Other risks may include liabilities for environmental damage and general civil liabilities, depletion of resources, and mandated expenditures for safety and pollution control. The energy sector may also be affected by economic cycles, rising interest rates, high inflation, technical progress, labor relations, legislative or regulatory changes, local and international policies, and adverse market conditions.

Sector Risk — Financial Services Sector Investments. To the extent a Fund concentrates its investments in companies in the financial services sector, it is more susceptible to the particular risks that may affect companies in that sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the financial services sector are subject to certain risks, including the risk of regulatory change, decreased liquidity in credit markets and unstable interest rates. Such companies may have concentrated portfolios, such as a high level of loans to one or more industries or sectors, which makes them vulnerable to economic conditions that affect such industries or sectors. Performance of such companies may be affected by competitive pressures and exposure to investments, agreements and counterparties, including credit products that, under certain circumstances, may lead to losses (e.g., subprime loans). Companies in the financial services sector are subject to extensive governmental regulation that may limit the amount and types of loans and other financial commitments

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they can make, and the interest rates and fees that they may charge. In addition, profitability of such companies is largely dependent upon the availability and the cost of capital.

Sector Risk — Health Care Sector Investments. To the extent a Fund concentrates its investments in companies in the health care sector, it is more susceptible to the particular risks that may affect companies in that sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the health care sector are subject to certain risks, including restrictions on government reimbursement for medical expenses, government approval of medical products and services, competitive pricing pressures, and the rising cost of medical products and services (especially for companies dependent upon a relatively limited number of products or services), among others. Performance of such companies may be affected by factors including, government regulation, obtaining and protecting patents (or the failure to do so), product liability and other similar litigation as well as product obsolescence.

Sector Risk — Industrials Sector Investments. To the extent a Fund concentrates its investments in companies in the industrials sector, it is more susceptible to the particular risks that may affect companies in that sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the industrials sector are subject to certain risks, including changes in supply and demand for their specific product or service and for industrial sector products in general, including decline in demand for such products due to rapid technological developments and frequent new product introduction. Performance of such companies may be affected by factors including government regulation, world events and economic conditions and risks for environmental damage and product liability claims.

Sector Risk — Information Technology Sector Investments. To the extent a Fund concentrates its investments in the information technology sector, it is more susceptible to the particular risks that may affect companies in that sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the information technology sectors are subject to certain risks, including the risk that new services, equipment or technologies will not be accepted by consumers and businesses or will become rapidly obsolete. Performance of such companies may be affected by factors including obtaining and protecting patents (or the failure to do so) and significant competitive pressures, including aggressive pricing of their products or services, new market entrants, competition for market share and short product cycles due to an accelerated rate of technological developments.

Such competitive pressures may lead to limited earnings and/or falling profit margins. As a result, the value of their securities may fall or fail to rise. In addition, many information technology sector companies have limited operating histories and prices of these companies’ securities historically have been more volatile than other securities, especially over the short term. Some companies in the information technology sector are facing increased government and regulatory scrutiny and may be subject to adverse government or regulatory action, which could negatively impact the value of their securities.

Sector Risk — Materials Investments. To the extent a Fund concentrates its investments in companies in the materials sector, it is more susceptible to the particular risks that may affect companies in the materials sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the materials sector are subject to certain risks, including that many materials companies are significantly affected by the level and volatility of commodity prices, exchange rates, import controls, increased competition, environmental policies, consumer demand, and events occurring in nature. For instance, natural events (such as earthquakes, hurricanes or fires in prime natural resource areas) and political events (such as government instability or military confrontations or actions) can affect the value of companies involved in business activities in the materials sector.

Performance of such companies may be affected by factors including, among others, that at times worldwide production of industrial materials has exceeded demand as a result of over-building or economic downturns, leading to poor investment returns or losses. Other risks may include liabilities for environmental damage and general civil liabilities, depletion of resources, and mandated expenditures for safety and pollution control. The

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materials sector may also be affected by economic cycles, rising interest rates, high inflation, technical progress, labor relations, legislative or regulatory changes, local and international policies, and adverse market conditions. In addition, prices of, and thus a Fund’s investments in, precious metals are considered speculative and are affected by a variety of worldwide and economic, financial and political factors. Prices of precious metals may fluctuate sharply.

Sector Risk — Utilities Sector Investments. To the extent a Fund concentrates its investments in companies in the energy sector, it is more susceptible to the particular risks that may affect companies in that sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the utilities sector are subject to certain risks, including risks associated with government regulation, interest rate changes, financing difficulties, supply and demand for services or products, intense competition, natural resource conservation and commodity price fluctuations.

Short Positions Risk

A Fund that establishes short positions introduces more risk to the Fund than a fund that only takes long positions (where the Fund owns the instrument or other asset) because the maximum sustainable loss on an instrument or other asset purchased (held long) is limited to the amount paid for the instrument or other asset plus the transaction costs, whereas there is no maximum price of the shorted instrument or other asset when purchased in the open market. Therefore, in theory, short positions have unlimited risk. A Fund’s use of short positions in effect “leverages” the Fund. Leverage potentially exposes a Fund to greater risks of loss due to unanticipated market movements, which may magnify losses and increase the volatility of returns. To the extent a Fund takes a short position in a derivative instrument or other asset, this involves the risk of a potentially unlimited increase in the value of the underlying instrument or other asset.

Small- and Mid-Cap Stock Risk

Securities of small- and mid-capitalization (small- and mid-cap) companies can, in certain circumstances, have a higher potential for gains than securities of larger, more established companies (larger companies) but are more likely to have more risk than larger companies. For example, small- and mid-cap companies may be more vulnerable to market downturns and adverse business or economic events than larger companies because they may have more limited financial resources and business operations. Small- and mid-cap companies are also more likely than larger companies to have more limited product lines and operating histories and to depend on smaller and generally less experienced management teams. Securities of small- and mid-cap companies may trade less frequently and in smaller volumes and may be less liquid and fluctuate more sharply in value than securities of larger companies. When a Fund takes significant positions in small- and mid-cap companies with limited trading volumes, the liquidation of those positions, particularly in a distressed market, could be prolonged and result in Fund investment losses that would affect the value of your investment in the Fund. In addition, some small- and mid-cap companies may not be widely followed by the investment community, which can lower the demand for their stocks.

Sovereign Debt Risk

The willingness or ability of a sovereign or quasi-sovereign debtor (a company or other entity that has significant government ownership) to repay principal and pay interest in a timely manner may be affected by a variety of factors, including its cash flow situation, the extent of its reserves, the availability of sufficient foreign exchange on the date a payment is due, the relative size of the debt service burden to the economy as a whole, the sovereign or quasi-sovereign debtor’s policy toward international lenders, and the political constraints to which such debtor may be subject. Quasi-sovereign debt obligations are typically less liquid and less standardized than sovereign debt obligations.

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With respect to sovereign or quasi-sovereign debt of emerging market issuers, investors should be aware that certain emerging market countries are among the largest debtors to commercial banks and foreign governments. At times, certain emerging market countries have declared moratoria on the payment of principal and interest on external debt. Certain emerging market countries have experienced difficulty in servicing their sovereign or quasi-sovereign debt on a timely basis and that has led to defaults and the restructuring of certain indebtedness to the detriment of debtholders. Sovereign debt risk is increased for emerging market issuers.

Special Purpose Acquisition Company (SPAC) Risk

A SPAC is typically a publicly traded company that raises investment capital via an initial public offering (IPO) for the purpose of acquiring one or more existing companies (or interests therein) via merger, combination, acquisition or other similar transactions (each a SPAC Transaction). The shares of a SPAC are issued in “units” that include one share of common stock and one warrant (or partial warrant) conveying the right to purchase additional shares or partial shares. Within 52 days after the closing of the IPO, the shares of common stock and the warrants comprising the units will begin to trade separately and become freely tradeable. After going public and until a SPAC Transaction is completed, a SPAC generally invests the proceeds of its IPO (less a portion retained to cover expenses) in U.S. Government securities, money market securities and/or cash. To the extent the SPAC is invested in cash or similar securities, this may impact a Fund’s ability to meet its investment objective(s). If a SPAC does not complete a SPAC Transaction within a specified period of time after going public, the SPAC is typically dissolved, at which point the invested funds are returned to the SPAC’s shareholders (less certain permitted expenses) and any warrants issued by the SPAC expire worthless. In some cases, the Fund will forfeit its right to exercise its warrants to receive additional shares even if a SPAC Transaction occurs if the Fund holding the warrant elects to redeem its shares and not participate in the SPAC Transaction.

Because SPACs often do not have an operating history or ongoing business other than seeking a SPAC Transaction, the value of their securities may be particularly dependent on the quality of their management and on the ability of the SPAC’s management to identify and complete a profitable SPAC Transaction. Some SPACs may pursue SPAC Transactions only within certain industries or regions, which may increase the volatility of an investment in them.

Other risks of investing in SPACs include that an attractive SPAC Transaction may not be identified at all (or any requisite approvals may not be obtained); a SPAC Transaction, once identified or effected, may prove unsuccessful and an investment in the SPAC Transaction may lose value; the warrants with respect to the SPAC held by a Fund may expire worthless or may be repurchased or retired by the SPAC; and an investment in a SPAC may be diluted by additional later offerings of interests in the SPAC or by other investors exercising existing rights to purchase shares of the SPAC.

Special Situations Risk

Securities of companies that are involved in an initial public offering or a major corporate event, such as a business consolidation or restructuring, may be exposed to heightened risk because of the high degree of uncertainty that can be associated with such events. Securities issued in initial public offerings often are issued by companies that are in the early stages of development, have a history of little or no revenues and may operate at a loss following the offering. It is possible that there will be no active trading market for the securities after the offering, and that the market price of the securities may be subject to significant and unpredictable fluctuations. Initial public offerings are subject to many of the same risks as investing in companies with smaller market capitalizations. To the extent a Fund determines to invest in initial public offerings, it may not be able to invest to the extent desired, because, for example, only a small portion (if any) of the securities being offered in an initial public offering are available to the Fund. The investment performance of a Fund during periods when it is unable to invest significantly or at all in initial public offerings may be lower than during periods when a Fund is able to do so. Securities purchased in initial public offerings which are sold within 12 months after purchase may result

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in increased short-term capital gains, which will be taxable to a Fund’s shareholders as ordinary income. Certain “special situation” investments are investments in securities or other instruments that may be classified as illiquid or lacking a readily ascertainable fair value. Certain special situation investments prevent ownership interests therein from being withdrawn until the special situation investment, or a portion thereof, is realized or deemed realized, which may negatively impact Fund performance. Investing in special situations may have a magnified effect on the performance of funds with small amounts of assets.

Stripped Securities Risk

Stripped securities are the separate income or principal components of debt securities. These securities are particularly sensitive to changes in interest rates, and therefore subject to greater fluctuations in price than typical interest bearing debt securities. For example, stripped mortgage-backed securities have greater interest rate risk than mortgage-backed securities with like maturities, and stripped treasury securities have greater interest rate risk (the risk of losses attributable to changes in interest rates) than traditional government securities with identical credit ratings.

Terrorism, War, Natural Disaster and Epidemic/Pandemic Risk

Terrorism, war, military confrontations and actions, and related geopolitical events (and their aftermath) have led, and in the future may lead, to increased short-term market volatility and may have adverse long-term effects on U.S. and world economies and markets generally. Likewise, natural and environmental disasters, such as, for example, earthquakes, fires, floods, hurricanes, tsunamis and weather-related phenomena generally, as well as widespread disease and virus epidemics, and pandemics, have been and can be highly disruptive to economies and markets, adversely affecting individual companies, sectors, industries, markets, currencies, interest and inflation rates, credit ratings, investor sentiment, and other factors affecting the value of the Funds’ investments. Given the increasing interdependence among global economies and markets, conditions in one country, market, or region are increasingly likely to adversely affect markets, issuers, and/or foreign exchange rates in other countries, including the U.S. These disruptions could prevent the Funds from executing advantageous investment decisions in a timely manner and negatively impact the Funds’ ability to achieve their investment objectives. Any such event(s) could have a significant adverse impact on the value and risk profile of the Funds.

U.S. Government Obligations Risk

While U.S. Treasury obligations are backed by the “full faith and credit” of the U.S. Government, such securities are nonetheless subject to credit risk (i.e., the risk that the U.S. Government may be, or may be perceived to be, unable or unwilling to honor its financial obligations, such as making payments). Securities issued or guaranteed by federal agencies or authorities and U.S. Government-sponsored instrumentalities or enterprises may or may not be backed by the full faith and credit of the U.S. Government. For example, securities issued by the Federal Home Loan Mortgage Corporation, the Federal National Mortgage Association and the Federal Home Loan Banks are neither insured nor guaranteed by the U.S. Government. These securities may be supported by the ability to borrow from the U.S. Treasury or only by the credit of the issuing agency, authority, instrumentality or enterprise and, as a result, are subject to greater credit risk than securities issued or guaranteed by the U.S. Treasury.

Valuation Risk

The sales price the Fund or a Portfolio Fund (or an underlying fund or other investment vehicle) could receive, or actually receives, for any particular investment may differ from the Fund’s or Portfolio Fund’s (or an underlying fund’s or other investment vehicle’s) valuation of the investment, particularly for securities that trade in thin or volatile markets, debt securities sold in amounts less than institutional-sized lots (typically referred to as odd lots) or securities that are valued using a fair value methodology that produces an estimate of the fair value of the security/instrument.

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Warrants and Rights Risk. Warrants are securities giving the holder the right, but not the obligation, to buy the stock of an issuer at a given price (generally higher than the value of the stock at the time of issuance) during a specified period or perpetually. Warrants may be acquired separately or in connection with the acquisition of securities. Warrants do not carry with them the right to dividends or voting rights and they do not represent any rights in the assets of the issuer. Warrants are subject to the risks associated with the security underlying the warrant, including market risk. Warrants may expire unexercised and subject a Fund to liquidity risk (the risk that it may not be possible for the Fund to liquidate the instrument at an advantageous time or price), which may result in Fund losses, including as a result of the warrants having little or no value. Rights are available to existing shareholders of an issuer to enable them to maintain proportionate ownership in the issuer by being able to buy newly issued shares. Rights allow shareholders to buy the shares below the current market price. Rights are typically short-term instruments that are valued separately and trade in the secondary market during a subscription (or offering) period. Holders can exercise the rights and purchase the stock, sell the rights or let them expire. Their value, and their risk of investment loss, is a function of that of the underlying security.

Zero-Coupon Bonds Risk. Zero-coupon bonds are bonds that do not pay interest in cash on a current basis, but instead accrue interest over the life of the bond. As a result, these securities are issued at a discount and their values may fluctuate more than the values of similar securities that pay interest periodically. Although these securities pay no interest to holders prior to maturity, interest accrued on these securities is reported as income to a Fund and affects the amounts distributed to its shareholders, which may cause the Fund to sell investments to obtain cash to make income distributions to shareholders, including at times when it may not be advantageous to do so.

Borrowings

Each Fund has a fundamental policy with respect to borrowing that can be found under the heading About the Funds’ Investments — Fundamental and Non-Fundamental Investment Policies. Specifically, each Fund may not borrow money or issue senior securities except to the extent permitted by the 1940 Act, the rules and regulations thereunder and any exemptive relief obtained by the Funds. In general, pursuant to the 1940 Act, a Fund may borrow money only from banks in an amount not exceeding 33¹⁄₃% of its total assets (including the amount borrowed) less liabilities (other than borrowings). Any borrowings that come to exceed this amount must be reduced within three days (not including Sundays and holidays) to the extent necessary to comply with the 33¹⁄₃% limitation.

The Trust, on behalf of the Funds, has entered into a revolving credit facility agreement (the Credit Agreement) with a syndicate of banks led by Citibank N.A., Wells Fargo Bank N.A. and JPMorgan Chase Bank, N.A. whereby the Funds and the other Columbia Funds (collectively, the Participating Funds) may borrow for the temporary funding of shareholder redemptions or for other temporary or emergency purposes. Pursuant to an amendment and restatement dated October 28, 2021, the Credit Agreement is a collective agreement among the Participating Funds, severally and not jointly, and permits the Participating Funds to borrow up to an aggregate commitment amount of $950 million (the Commitment Limit) at any time outstanding, subject to asset coverage and other limitations as specified in the Credit Agreement. Each Fund may borrow up to the maximum amount allowable under its current Prospectus and this SAI, subject to various other legal, regulatory or contractual limits. See About the Funds’ Investments — Fundamental and Non-Fundamental Investment Policies.

Borrowing results in interest expense and other fees and expenses for the Funds that may impact the Funds’ net expense ratios. The costs of borrowing may reduce Fund returns. Interest under the Credit Agreement is charged to each Fund at a variable rate, and each Fund pays a commitment fee equal to its pro rata share of the amount of the credit facility. The availability of assets under the Credit Agreement can be affected by other Participating Funds’ borrowings under the agreement. As such, a Fund may be unable to borrow (or borrow further) under the Credit Agreement if the Commitment Limit has been reached.

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Short Sales

A Fund may sometimes sell securities short when it owns an equal amount of such securities, contracts or instruments, or owns securities that are convertible or exchangeable into, without payment of further consideration, at least an equal amount of such securities, contracts or instruments. as those securities sold short. This is a technique known as selling short “against the box.” If a Fund makes a short sale “against the box,” it would not immediately deliver the securities sold and would not receive the proceeds from the sale. The seller is said to have a short position in the securities sold until it delivers the securities sold, at which time it receives the proceeds of the sale. To secure its obligation to deliver securities sold short, a Fund will deposit in escrow in a separate account with the custodian an equal amount of the securities sold short or securities convertible into or exchangeable for such securities. A Fund can close out its short position by purchasing and delivering an equal amount of the securities sold short, rather than by delivering securities already held by a Fund, because a Fund might want to continue to receive interest and dividend payments on securities in its portfolio that are convertible into the securities sold short.

The Funds generally may not sell securities short or maintain a short position, except short sales “against the box.” Other Columbia Funds, including the Portfolio Funds, under certain circumstances, may engage in short sales that are not “against the box,” which are sales by a Fund of securities or commodity futures contracts that it does not own in hopes of purchasing the same security at a later date at a lower price. The technique is also used to protect a profit in a long-term position in a security, contract or instrument. To make delivery to the buyer, a Fund must borrow or purchase the security. If borrowed, a Fund is then obligated to replace the security borrowed from the third party, so a Fund must purchase the security at the market price at a later time. If the price of the security has increased during this time, then a Fund will incur a loss equal to the increase in price of the security from the time of the short sale plus any premiums and interest paid to the third party. (Until the security is replaced, a Fund is required to pay to the lender amounts equal to any dividends or interest which accrue during the period of the loan. To borrow the security, a Fund also may be required to pay a premium, which would increase the cost of the security sold. The proceeds of the short sale will be retained by the broker, to the extent necessary to meet the margin requirements, until the short position is closed out.)

Short sales by a Fund that are not made “against the box” create opportunities to increase a Fund’s return but, at the same time, involve specific risk considerations and may be considered a speculative technique. Because a Fund in effect profits from a decline in the price of the securities sold short without the need to invest the full purchase price of the securities on the date of the short sale, a Fund’s NAV tends to increase more when the securities it has sold short decrease in value, and to decrease more when the securities it has sold short increase in value, than if it had not engaged in such short sales. The amount of any gain will be decreased, and the amount of any loss increased, by the amount of any premium, dividends or interest a Fund may be required to pay in connection with the short sale. Short sales could potentially involve unlimited loss, as the market price of securities sold short may continually increase, although a Fund can mitigate any such losses by replacing the securities sold short. Under adverse market conditions, a Fund might have difficulty purchasing securities to meet its short sale delivery obligations, and might have to sell portfolio securities to raise the capital necessary to meet its short sale obligations at a time when fundamental investment considerations would not favor such sales. There is also the risk that the third party to the short sale may fail to honor its contract terms, causing a loss to a Fund.

Short sales “against the box” entail many of the same risks and considerations described above regarding short sales not “against the box.” However, when a Fund sells short “against the box” it typically limits the amount of securities that it has leveraged. A Fund’s decision to make a short sale “against the box” may be a technique to hedge against market risks when the Investment Manager believes that the price of a security may decline, causing a decline in the value of a security owned by a Fund or a security convertible into or exchangeable for such security. In such case, any future losses in a Fund’s long position would be reduced by a gain in the short position. The extent to which such gains or losses in the long position are reduced will depend upon the amount of securities sold short relative to the amount of the securities a Fund owns, either directly or

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indirectly, and, in the case where a Fund owns convertible securities, changes in the investment values or conversion premiums of such securities. Short sales may have adverse tax consequences to a Fund and its shareholders.

A Fund’s successful use of short sales also will be subject to the ability of the Investment Manager to predict movements in the directions of the relevant market. A Fund therefore bears the risk that the Investment Manager will incorrectly predict future price directions. In addition, if a Fund sells a security short, and that security’s price goes up, a Fund will have to make up the margin on its open position (i.e., purchase more securities on the market to cover the position). It may be unable to do so and thus its position may not be closed out. There can be no assurance that a Fund will not incur significant losses in such a case.

In the view of the SEC, a short sale involves the creation of a “senior security” as such term is defined in the 1940 Act, unless the sale is “against the box” and the securities sold short are placed in a segregated account (not with the broker), or unless a Fund’s obligation to deliver the securities sold short is “covered” by designating on the Fund’s books and records cash, U.S. Government securities or other liquid debt or equity securities in an amount equal to the difference between the market value of the securities sold short at the time of the short sale and any such collateral required to be deposited with a broker in connection with the sale (not including the proceeds from the short sale), which difference is adjusted daily for changes in the value of the securities sold short. The total value of the cash, U.S. Government securities or other liquid debt or equity securities designated on the Fund’s books and records may not at any time be less than the market value of the securities sold short at the time of the short sale.

Lending Securities

Securities lending refers to the lending of a Fund’s portfolio securities. GSAL serves as the Funds’ securities lending agent pursuant to a securities lending agreement approved by the Board. Subject to certain limitations (including that, with respect to a particular security, GSAL will not lend more than 5% of the outstanding shares of the issuer of such security held by the Trust in the aggregate), each Fund (other than Columbia Thermostat Fund) may lend portfolio securities to broker-dealers, banks or other institutional borrowers of securities that the Funds’ securities lending agent has determined are creditworthy under guidelines established by the Board. A lending Fund pays a portion of income earned on lending transactions to GSAL, and also may pay administrative and custodial fees in connection with loans of securities. See Investment Advisory and Other Services — Other Service Providers — Securities Lending Agent for more information about the income and fees associated with the Funds’ securities lending activities.

The Funds receive collateral equal to at least 102% for domestic issuers and 105% for foreign issuers of the value of the securities loaned. Collateral is invested by the Funds in a third-party institutional government money market fund in accordance with investment guidelines contained in the securities lending agreement and approved by the Board. If the market value of the loaned securities goes up, the securities lending agent will require additional collateral from the borrower. If the market value of the loaned securities goes down, the borrower may request that some collateral be returned. Funds participating in securities lending bear the risk of loss in connection with investment of collateral received from the borrowers. To the extent that the value, including any investment return, of a Fund’s investment of the collateral declines below the amount owed to a borrower, a Fund may incur losses that exceed the amount it earned on lending the security.

Securities lending involves counterparty risk, including the risk that a borrower may not return a loaned security and the proceeds from the sale of the collateral will not be sufficient to replace the borrowed security. Counterparty risk also includes a potential loss of rights in the collateral if the borrower or the securities lending agent defaults or enters bankruptcy. This risk is increased if a Fund’s loans are concentrated with a single borrower or limited number of borrowers. In the event of bankruptcy or other default of a borrower, a Fund could experience delays both in liquidating the loan collateral and in recovering the loaned securities. A Fund could also sustain losses arising from expenses of enforcing the Fund’s rights. GSAL has agreed to indemnify the

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Funds from losses resulting from a borrower’s failure to return a loaned security when due, but such indemnification does not extend to losses associated with declines in the value of collateral investments.

Loans are subject to termination at any time by the Funds or a borrower. A lending Fund does not have the right to vote loaned securities. In accordance with the procedures adopted by the Board, a lending Fund will generally attempt to call all loaned securities back to permit the exercise of voting rights, if time and jurisdictional restrictions permit. There is no guarantee that all loans can be recalled.

During the existence of the loan, the borrower must pay over to the lender amounts equivalent to any dividends, interest or other distributions on the loaned securities, as well as interest on such amounts, less applicable taxes. Such payments to the Fund do not constitute “qualified dividends” taxable at the same rate as long-term capital gains, even if the actual dividends would have constituted qualified dividends had the Fund held the securities.

Portfolio Turnover

A change in the securities held by a Fund is known as “portfolio turnover.” High portfolio turnover (e.g., over 100% annually) involves correspondingly greater expenses to the Fund, including brokerage commissions or dealer mark-ups and other transaction costs on the sale of securities and reinvestments in other securities. Such sales may also result in adverse tax consequences to a Fund’s shareholders. The trading costs and tax effects associated with portfolio turnover may adversely affect a Fund’s performance.

For each Fund’s portfolio turnover rate, see the Financial Highlights section in the prospectus for that Fund.

For the fiscal year ended December 31, 2021, Columbia Thermostat Fund’s portfolio turnover rate was 49%, and for the fiscal year ended December 31, 2020, it was 97%. For the fiscal year ended December 31, 2019, the Fund’s portfolio turnover rate was 158%, and for the year before that, it was 122%. Columbia Thermostat Fund’s portfolio turnover rate is based on changes in the S&P 500^® Index, which dictates the Fund’s purchase and sale of shares of the underlying Portfolio Funds in which it invests. Under normal conditions, the portfolio turnover rate for Columbia Thermostat Fund is expected to be below 150%. Because Columbia Thermostat Fund is a Fund of Funds that exchanges shares of the Portfolio Funds at NAV, the costs associated with Columbia Thermostat Fund’s portfolio turnover rate are lower than the costs that would be associated with another fund that had the same portfolio turnover rate but directly bore the trading costs of its portfolio transactions.

The other Funds’ portfolio turnover rates generally decreased but did not vary significantly from their normal ranges between 2020 and 2021.

The 2022 portfolio turnover rate for Columbia Acorn USA will be impacted by the repositioning of the Fund’s portfolio in connection with the May 1, 2022 increase in the market capitalization of the companies in which the Fund may invest, which is being implemented along with certain other changes in advance of a likely future proposal to merge Columbia Acorn USA with and into Columbia Acorn Fund. Columbia Acorn USA’s portfolio turnover rate is expected to increase significantly during 2022 as a result of the repositioning. See About the Funds’ Investments — Information Regarding Risks — Frequent Trading Risk for more information.

Disclosure of Portfolio Information

The Board and the Investment Manager believe that the investment ideas and trading strategies of the Investment Manager with respect to portfolio management of a Fund should benefit the Fund and its shareholders, and do not want to afford speculators an opportunity to profit by anticipating Fund trading strategies or by using Fund portfolio holdings information for stock picking. However, the Board also believes that knowledge of a Fund’s portfolio holdings can assist shareholders in monitoring their investments, making asset allocation decisions, and evaluating portfolio management techniques.

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The Board has therefore adopted policies and procedures relating to disclosure of the Funds’ portfolio securities. These policies and procedures are intended to protect the confidentiality of Fund portfolio holdings information and generally prohibit the release of such information until it is made available to the general public. It is the policy of the Funds not to provide or permit others to provide portfolio holdings on a selective basis, and the Investment Manager does not intend to selectively disclose portfolio holdings in advance of public dissemination.

The Investment Manager does not expect that such holdings information will be selectively disclosed, except where necessary for the Funds’ operation or where there are other legitimate business purposes for doing so and, in any case, where conditions are met that are designed to protect the interests of the Funds and their shareholders, including that the recipients are subject to a duty of confidentiality, including a duty not to trade on the nonpublic information. These policies and procedures prohibit Ameriprise Financial, the Investment Manager and the Funds’ other service providers from entering into any agreement to disclose Fund portfolio holdings information or trading strategies in violation of the policies and procedures and from entering into any agreement to disclose portfolio information in exchange for any form of consideration. The policies and procedures incorporate and adopt the supervisory controls and recordkeeping requirements established in the Investment Manager’s policies and procedures. The Investment Manager has also adopted policies and procedures to monitor for compliance with the Funds’ portfolio holdings disclosure policies and procedures.

Although the Investment Manager seeks to limit the selective disclosure of portfolio holdings information and such selective disclosure is monitored under the Funds’ compliance program for conformity with the policies and procedures, there can be no assurance that the policies and procedures will protect the Funds from the potential misuse of holdings information by individuals or firms in possession of that information.

Public Disclosures

The Funds’ portfolio holdings are currently disclosed to the public through required filings with the SEC and on the Funds’ website. Once posted, the portfolio holdings information will remain available on the website until at least the date on which a Fund files a Form N-CSR or Form N-PORT for the period that includes the date as of which the information is current. The Funds’ complete holdings (and in the case of Columbia Thermostat Fund, percentage holdings of the Portfolio Funds) are disclosed on the Funds’ website at columbiathreadneedle.com/us as of a month-end no earlier than 30 to 40 calendar days after such month-end. In addition, the largest 10 to 15 holdings of each Fund are usually available sooner, approximately 15 calendar days after each month-end. Purchases and sales of the Funds’ portfolio securities can take place at any time, so the portfolio holdings information available on the website may not always be current. The scope of the information disclosed on the Funds’ website pursuant to the policies and procedures described above also may change from time to time, without prior notice.

The Funds file their portfolio holdings with the SEC for each fiscal quarter on either Form N-CSR (with respect to each annual period and semiannual period) or Form N-PORT (with respect to the first and third quarters of the Funds’ fiscal year). Shareholders may obtain the Funds’ Forms N-CSR and N-PORT filings on the SEC’s website at sec.gov, a link to which is provided on the Funds’ website at columbiathreadneedleus.com. You may call the SEC at 202.551.8090 for information about the SEC’s website.

The Funds, the Investment Manager, Ameriprise Financial or their affiliates may include portfolio holdings information that has already been made public through a web posting or SEC filing in marketing literature and other communications to shareholders, financial advisors or other parties. In addition, certain advisory clients of the Investment Manager that follow a strategy similar to that of a Fund have access to their own custodial account’s portfolio holdings information before such Fund posts its holdings on the Funds’ website at www.columbiamanagement.com. It is possible that when clients observe transactions in their own accounts, they may infer transactions of the Funds prior to public disclosure of Fund transactions.

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Other Disclosures

Pursuant to the policies and procedures described above, the Funds may selectively disclose their portfolio holdings information in advance of public disclosure on a confidential basis to various Fund service providers that require such information for the legitimate business purpose of assisting the Funds with day-to-day business affairs.

In determining the existence of a legitimate business purpose for making portfolio disclosures, the following factors, among others, are considered: (i) any prior disclosure must be consistent with the anti fraud provisions of the federal securities laws and the fiduciary duties of the Investment Manager; (ii) any conflicts of interest between the interests of Fund shareholders, on the one hand, and those of the Investment Manager, the Distributor or any affiliated person of a Fund, the Investment Manager or Distributor on the other; and (iii) any prior disclosure to a third party, although subject to a confidentiality agreement, would not make conduct lawful that is otherwise unlawful.

In addition, the Funds periodically disclose their portfolio information on a confidential basis to various service providers that require such information to assist the Funds with their day-to-day business affairs. In addition to the Investment Manager and its affiliates, these service providers include, but are not limited to, affiliates of the Investment Manager, the Funds’ custodian, any sub-custodians, independent registered public accounting firm, legal counsel, operational system vendors, financial printers, proxy solicitor and proxy voting service provider, as well as ratings agencies that maintain ratings on certain Funds. These service providers are required to keep such information confidential, and are prohibited from trading based on the information or otherwise using the information except as necessary in providing services to the Funds. The Funds also may disclose portfolio holdings information to broker-dealers and certain other entities in connection with potential transactions and management of the Funds, provided that reasonable precautions, including limitations on the scope of the portfolio holdings information disclosed, are taken to avoid any potential misuse of the disclosed information.

The Fund also discloses portfolio holdings information as required by federal, state or international securities laws, and may disclose portfolio holdings information in response to requests by governmental authorities, or in connection with litigation or potential litigation, a restructuring of a holding, where such disclosure is necessary to participate or explore participation in a restructuring of the holding (e.g., as part of a bondholder group), or to the issuer of a holding, pursuant to a request of the issuer or any other party who is duly authorized by the issuer.

Neither the Funds nor Ameriprise Financial, the Investment Manager or their affiliates receive compensation or consideration from the service providers for the portfolio holdings information. In addition to Ameriprise Financial, the Investment Manager and their affiliates, including Threadneedle International Limited, these service providers are listed below. Portfolio holdings information disclosed to such recipients is current as of the time of its disclosure, is disclosed to each recipient solely for purposes consistent with the services described below, and has been authorized in accordance with the policy.

IDENTITY OF RECIPIENT	PURPOSE OF DISCLOSURE	FREQUENCY OF DISCLOSURE
JPMorgan	Funds’ Custodian; receives trade files containing information for the Funds.	Daily
FactSet Research Data Systems, Inc.	Provides quantitative analysis, charting and fundamental data to investment, marketing, performance and distribution personnel.	Daily

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IDENTITY OF RECIPIENT	PURPOSE OF DISCLOSURE	FREQUENCY OF DISCLOSURE
Interactive Data Corporation (IDC)	Provides statistical fair valuation services to support the Investment Manager.	As needed
Merrill Corporation	Printer for the Funds’ prospectuses, SAIs, supplements and sales materials.	As needed
R.R. Donnelley & Sons Co.	Printer and EDGAR filer for the Funds’ prospectuses, SAIs, shareholder reports, supplements and sales materials.	As needed
RegEd, Inc.	Review of external and certain internal communications prior to dissemination.	Daily
Abel Noser	Evaluation and assessment of trading activity, execution and practices by the Investment Manager.	As needed, generally no less than quarterly
Bloomberg, L.P.	Provides Bloomberg Portfolio and Risk Analytics (PORT).	Daily
BlackRock, Inc.	Used for front office trading and analytics, back office settlements, portfolio accounting and reconciliations, collateral management, portfolio risk oversight, compliance mandate monitoring and portfolio performance calculations.	Daily
GSAL	Funds’ securities lending agent.	As needed in connection with the Funds’ securities lending program
Institutional Shareholder Services, Inc. (ISS)	Proxy voting administration and research on proxy matters.	Daily
Perkins Coie LLP	Legal counsel to the Funds.	As needed
Faegre Drinker Biddle & Reath LLP	Legal counsel to the Independent Trustees.	As needed

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IDENTITY OF RECIPIENT	PURPOSE OF DISCLOSURE	FREQUENCY OF DISCLOSURE
ING Insurance Company	Provides quarterly fact sheets.	Quarterly
PricewaterhouseCoopers LLP	Funds’ independent registered public accounting firm.	As needed
Fidelity National Information Services (InvestOne)	Provides InvestOne portfolio accounting system.	Daily
Morningstar, Inc.	Provides analysis of Fund performance and fee/expense data.	As needed, typically once annually
Broadridge, Inc. (formerly, Lipper, Inc.)	Provides analysis of Fund performance and fee/expense data.	As needed, typically once annually
CTM	Provides trade allocation and acceptance services.	Daily
Harte-Hanks	Printer for Fund prospectuses, factsheets, and annual and semi-annual reports.	As needed
Universal Wilde	Provides printing and mailing services for Fund prospectuses, annual and semi-annual reports, and supplements.	As needed
Broadridge	Provides printing on demand.	As needed
Equifax	Provides services to ensure that the Investment Manager, Columbia Management and their affiliates do not violate Office of Foreign Assets Control (OFAC) rules and regulations.	As needed

Pursuant to agreements in such form as the Chief Compliance Officer (CCO) of the Funds may require, these service providers are required to keep such information confidential, and are prohibited from trading based on the information or otherwise using the information except as necessary in providing services to the Funds.

The Funds have authorized the Investment Manager’s President (and his or her designated subordinates) to make appropriate disclosures of the Funds’ holdings to certain Ameriprise Financial affiliates (to provide monitoring of compliance with codes of ethics and to monitor risk and various holdings limitations that must be aggregated with affiliated funds, among other purposes), to provide the Custodian, sub-custodians and pricing service with daily trade information, to disclose necessary portfolio information to the Funds’ proxy service. The Funds have also authorized the Investment Manager’s President (and his or her designated subordinates) to disclose portfolio information to independent auditors in connection with audit procedures. In addition, the Funds have authorized Ameriprise Financial and the Investment Manager’s President (and his or her designated subordinates) to disclose necessary information to printing firms engaged by Ameriprise Financial to prepare periodic reports to Fund shareholders.

The Investment Manager uses a variety of broker-dealers and other agents to effect securities transactions on behalf of the Funds. These broker-dealers become aware of the Funds’ intentions, transactions and positions,

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in performing their functions. Further, the Funds’ ability to identify and execute transactions in securities is dependent, in part, on information provided to the Investment Manager by broker-dealers who are market makers in certain securities or otherwise have the ability to assist the Funds in executing their orders. To facilitate that process, the Board has authorized the Investment Manager’s President and Director of Global Trading (and their designated subordinates) to disclose portfolio information or anticipated transactions to broker-dealers who may execute Fund transactions. This disclosure is limited to that information necessary to effect the Funds’ securities transactions and assist the Investment Manager in seeking to obtain best execution.

The CCO is responsible for implementation of the Funds’ portfolio holdings disclosure policies and procedures. The CCO is required to report to the Board any violations of the policies and procedures that come to his attention and may approve non-public disclosures of a Fund’s portfolio holdings. Such disclosure must be consistent with the policies and procedures in that it furthers a legitimate business purpose of a Fund, is therefore in the best interests of that Fund’s shareholders and is appropriately reported to the Board.

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INVESTMENT ADVISORY AND OTHER SERVICES

The Investment Manager and Investment Advisory Services

Columbia Wanger Asset Management, LLC (CWAM or the Investment Manager) serves as the investment adviser for the Funds, the series of Wanger Advisors Trust and other private funds and institutional accounts. The Investment Manager and its predecessors have managed mutual funds, including Columbia Acorn Fund, since 1992. The Investment Manager is located at 71 S. Wacker Drive, 25th Floor, Chicago, Illinois 60606. It is a registered investment adviser and wholly owned subsidiary of Columbia Management, which is a wholly owned subsidiary of Ameriprise Financial.

As of March 31, 2022, the Investment Manager had assets under management of approximately $9.2 billion.

The Investment Manager and its investment advisory affiliates (Affiliates or Participating Affiliates) around the world may coordinate in providing services to their clients. Such coordination may include functional leadership of the business (the “global” business). From time to time, the Investment Manager may engage its Affiliates or Participating Affiliates to provide a variety of services such as investment research, investment monitoring, trading, and discretionary investment management (including portfolio management) to certain accounts managed by the Investment Manager, including the Funds. These Affiliates or Participating Affiliates will provide services to the Funds and other accounts of the Investment Manager either pursuant to delegation agreements, personnel-sharing agreements or similar inter-company or other arrangements or relationships and the Funds will pay no additional fees and expenses as a result of any such arrangements or relationships. These Affiliates or Participating Affiliates, like the Investment Manager, are direct or indirect subsidiaries of Ameriprise Financial and are registered with the appropriate respective regulators in their home jurisdictions and, where required, the SEC and the CFTC in the United States.

Pursuant to some of these arrangements or relationships, certain personnel of these Affiliates or Participating Affiliates may serve as “associated persons” or officers of the Investment Manager and, in this capacity, subject to the oversight and supervision of the Investment Manager and consistent with the investment objectives, policies and limitations set forth in the Funds’ prospectuses and this SAI, and with the Investment Manager’s and the Funds’ compliance policies and procedures, may provide such services to the Funds.

Specifically, pursuant to such arrangements, certain Fund portfolio managers are employees of Columbia Management and certain investment personnel of the Investment Manager serve as portfolio managers of other Columbia Funds advised by Columbia Management. The Funds pay no additional fees or expenses as in connection with such arrangements.

At a special meeting held on May 27, 2010, as recommended by the Board, shareholders approved the Trust’s Advisory Agreement (with respect to each of the Funds other than Columbia Acorn European Fund), which initially took effect immediately and continued in effect through July 31, 2011. At a Meeting held on March 2, 2011, the Board approved the Advisory Agreement with respect to Columbia Acorn European Fund, to be effective August 19, 2011. The Advisory Agreement continues from year to year with respect to each Fund, until terminated by either the Trust or the Investment Manager, as long as it is specifically approved at least annually by either the Board or by a vote of the majority of the outstanding shares of the Fund and by the vote of a majority of the Independent Trustees, cast in person at a meeting called for the purpose of voting on such approval.

The Advisory Agreement generally provides that, subject to the overall supervision and control of the Board, the Investment Manager shall have supervisory responsibility for the general management and investment of the Funds’ assets and will endeavor to preserve the autonomy of the Trust. Under the Advisory Agreement, the Investment Manager is authorized to make decisions to buy and sell securities and other assets for the Funds, to place the Funds’ portfolio transactions with broker-dealers and to negotiate the terms of such transactions

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including brokerage commissions on brokerage transactions on behalf of the Funds. The Investment Manager is authorized to exercise discretion within the Trust’s policy concerning allocation of its portfolio brokerage, as permitted by law, and in so doing shall not be required to make any reduction in its investment advisory fees. The Investment Manager is required to use its best efforts to seek to obtain the best overall terms available for portfolio transactions for each Fund. See Brokerage Allocation and Other Practices—General Brokerage Policy, Brokerage Transactions and Broker Selection.

The Investment Manager, at its own expense, provides office space, facilities and supplies, equipment and personnel for the performance of its functions under the Advisory Agreement. The Trust pays all compensation of the Independent Trustees.

Under the Advisory Agreement, the Investment Manager is not liable for any loss suffered by a Fund or its shareholders as a result of any error of judgment, or any loss arising out of any investment, or as a consequence of any other act or omission of the Investment Manager or any of its affiliates in the performance of the Investment Manager’s duties under the agreement, except for (i) with respect to acts or omissions in respect of investment activities, liability resulting from willful misfeasance, bad faith, reckless disregard or gross negligence, and (ii) with respect to all other matters, liability resulting from bad faith, intentional misconduct or negligence, on the part of the Investment Manager or its affiliates.

A discussion regarding the basis of the Board’s approval of the continuation, through July 31, 2022, of the Advisory Agreement with respect to each Fund is available in the Funds’ annual report to shareholders for the fiscal period ended December 31, 2021. A discussion regarding the Board’s approval of the continuation, through July 31, 2023, of the Advisory Agreement with respect to each Fund is expected to be available in the Funds’ semiannual report to shareholders for the fiscal period ending June 30, 2022.

Advisory Fee Rates

The Funds pay the Investment Manager an annual fee for its investment advisory services as shown in the section entitled Fees and Expenses — Annual Fund Operating Expenses in each Fund’s prospectus. The advisory fee is calculated as a percentage of the average daily net assets of each Fund and is paid monthly. The Investment Manager may pay amounts from its own assets to the Distributor and/or to Financial Intermediaries for services they provide.

The Investment Manager also receives advisory fees from certain of the Portfolio Funds in which Columbia Thermostat Fund invests. Please refer to the Portfolio Funds’ respective prospectuses, which are available on the Columbia Funds website at columbiathreadneedle.com/us and on the SEC’s website at sec.gov.

The Investment Manager receives a monthly investment advisory fee based on each Fund’s average daily net assets at the following annual rates:

	Assets	Rate of Fee
Columbia Acorn Fund	Up to $700 million		0.740%
	$700 million to $2 billion		0.690%
	$2 billion to $6 billion		0.640%
	$6 billion and over		0.630%
Columbia Acorn International	Up to $100 million		1.190%
	$100 million to $500 million		0.940%
	$500 million and over		0.740%
Columbia Acorn USA*	Up to $700 million		0.740%
	$700 million to $2 billion		0.690%
	$2 billion to $6 billion		0.640%
	$6 billion and over		0.630%

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	Assets	Rate of Fee
Columbia Acorn International Select	Up to $500 million		0.890%
	$500 million and over		0.850%
Columbia Thermostat Fund	All assets		0.100%
Columbia Acorn European Fund	Up to $100 million		1.190%
	$100 million to $500 million		0.940%
	$500 million and over		0.740%

* Prior to May 1, 2022, Columbia Acorn USA paid investment advisory fees at the annual rate of 0.940% on the first $200 million, 0.890% from $200 million to $500 million, 0.840% from $500 million to $2 billion, 0.800% from $2 billion to $3 billion and 0.700% for $3 billion and over.

The Investment Manager received fees from the Funds for its services as reflected in the following chart, which shows the advisory fees paid to the Investment Manager for the three most recently completed fiscal years.

Advisory Fees Paid by the Funds

Fund	Fiscal Year Ended December 31, 2021		Fiscal Year Ended December 31, 2020		Fiscal Year Ended December 31, 2019
Columbia Acorn Fund	$	32,530,585	$	27,510,670	$	28,458,416
Columbia Acorn International	$	19,533,295	$	18,520,125	$	21,150,671
Columbia Acorn USA	$	3,011,389	$	2,571,334	$	2,798,827
Columbia Acorn International Select	$	4,342,199	$	2,613,625	$	1,182,279
Columbia Acorn European Fund	$	1,796,167	$	978,881	$	922,332
Columbia Thermostat Fund	$	2,037,101	$	1,141,494	$	691,695

Fee and Expense Limitations—Agreements of the Investment Manager and its Affiliates

Amounts reimbursed by the Investment Manager under prior contractual arrangements are reflected in the table below.

Expenses Reimbursed

	Fiscal year ended December 31, 2021		Fiscal year ended December 31, 2020		Fiscal year ended December 31, 2019
Columbia Acorn Fund		—	$	3,090	$	17,300
Columbia Acorn International	$	376,336	$	894,866	$	627,433
Columbia Acorn USA	$	19,062	$	113,004	$	117,850
Columbia Acorn International Select	$	1,037,358	$	616,055	$	255,234
Columbia Acorn European Fund	$	310,320	$	340,414	$	341,396
Columbia Thermostat Fund	$	869,098	$	740,077	$	539,471

With respect to Columbia Acorn Fund, the Investment Manager has contractually agreed to waive fees and reimburse certain expenses of the Fund so that the Fund’s ordinary operating expenses (excluding transaction costs and certain other investment-related expenses, interest and fees on borrowings, and expenses associated with the Fund’s investment in other investment companies, if any) do not exceed the annual rates of 1.11% for Class A

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shares, 0.86% for Class Adv shares, 1.86% for Class C shares, 0.86% for Class Inst shares, 0.84% for Class Inst2 shares and 0.79% for Class Inst3 shares, from May 1, 2022 through April 30, 2023. This arrangement may only be amended or terminated with approval from the Board and the Investment Manager.

With respect to Columbia Acorn International, the Investment Manager has contractually agreed to waive fees and reimburse certain expenses of the Fund so that ordinary operating expenses (excluding transaction costs and certain other investment-related expenses, interest and fees on borrowings, and expenses associated with the Fund’s investment in other investment companies, if any) do not exceed the annual rates of 1.23% for Class A shares, 0.98% for Class Adv shares, 1.98% for Class C shares, 0.98% for Class Inst shares, 0.92% for Class Inst2 shares, 0.88% for Class Inst3 shares and 1.48% for Class R shares, from May 1, 2022 through April 30, 2023. This arrangement may only be amended or terminated with approval from the Board and the Investment Manager.

With respect to Columbia Acorn USA, the Investment Manager has contractually agreed to waive fees and reimburse certain expenses of the Fund so that the Fund’s ordinary operating expenses (excluding transaction costs and certain other investment-related expenses, interest and fees on borrowings and expenses associated with the Fund’s investment in other investment companies, if any) do not exceed the annual rates of 1.08% for Class A shares, 0.83% for Class Adv shares, 1.83% for Class C shares, 0.83% for Class Inst shares, 0.81% for Class Inst2 shares and 0.76% for Class Inst3 shares, from May 1, 2022 through April 30, 2023. This arrangement may only be amended or terminated with approval from the Board and the Investment Manager.

With respect to Columbia Acorn International Select, effective July 1, 2016, the Investment Manager agreed to waive fees and reimburse certain expenses of the Fund for an indefinite term, and in April 2017 restated that agreement to clarify that the Investment Manager’s intention was to waive fees and reimburse expenses so that ordinary operating expenses (excluding transaction costs and certain other investment-related expenses, interest and fees on borrowings and expenses associated with the Fund’s investment in other investment companies, if any) (i) did not exceed the annual rate of 1.15% for Class Inst shares and (ii) the Fund’s other share classes did not exceed annual rates to be restated each year by the Investment Manager to account for certain differentials between the Fund’s Class Inst shares and other share classes. From May 1, 2022 through April 30, 2023, the Investment Manager has contractually agreed to waive fees and reimburse certain expenses of Columbia Acorn International Select so that the ordinary operating expenses (excluding transaction costs and certain other investment-related expenses, interest and fees on borrowings and expenses associated with the Fund’s investment in other investment companies, if any) do not exceed the annual rates of 1.24% for Class A shares, 0.99% for Class Adv shares, 1.99% for Class C shares, 0.99% for Class Inst shares, 0.89% for Class Inst2 shares and 0.84% for Class Inst3 shares. This arrangement may only be amended or terminated with approval from the Board and the Investment Manager.

With respect to Columbia Acorn European Fund, the Investment Manager has contractually agreed to waive fees and reimburse certain expenses of the Fund so that the ordinary operating expenses (excluding transaction costs and certain other investment-related expenses, interest and fees on borrowings and expenses associated with the Fund’s investment in other investment companies, if any) do not exceed the annual rates of 1.45% for Class A shares, 1.20% for Class Adv shares, 2.20% for Class C shares, 1.20% for Class Inst shares, 1.14% for Class Inst2 shares and 1.11% for Class Inst3 shares, from May 1, 2022 through April 30, 2023. This arrangement may only be amended or terminated with approval from the Board and the Investment Manager.

With respect to Columbia Thermostat Fund, the Investment Manager has contractually agreed to waive fees and reimburse certain expenses of the Fund so that the Fund’s ordinary operating expenses (excluding transaction costs and certain other investment-related expenses, interest and fees on borrowings and expenses associated with the Fund’s investment in the Portfolio Funds (acquired funds)) do not exceed the annual rates of 0.50% for Class A shares, 0.25% for Class Adv shares, 1.25% for Class C shares, 0.25% for Class Inst shares, 0.20% for Class Inst2 shares and 0.16% for Class Inst3 shares, from May 1, 2022 through April 30, 2023. This arrangement may only be amended or terminated with approval from the Fund and the Investment Manager. In addition to the fees and expenses paid by Columbia Thermostat Fund directly, Columbia Thermostat Fund pays its pro rata share of the fees and expenses of the Portfolio Funds in which it invests.

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Fees Waived

The Funds pay the Transfer Agent, an affiliate of the Investment Manager, a fee for its services, as described under Investment Advisory and Other Services — The Investment Manager and Investment Advisory Services — Other Service Providers.

Amounts waived by the Transfer Agent under prior contractual arrangements are reflected in the table below.

	Fiscal year ended December 31, 2021		Fiscal year ended December 31, 2020		Fiscal year ended December 31, 2019
Columbia Acorn Fund	$	3,081	$	2,205	$	509,459
Columbia Acorn International	$	33,266	$	27,117	$	124,816
Columbia Acorn USA	$	3,764	$	4,905	$	5,191
Columbia Acorn International Select		—	$	2,959	$	1,243
Columbia Acorn European Fund	$	2,758	$	540	$	321
Columbia Thermostat Fund		—		—	$	1,144

For the period beginning May 1, 2022 and ending April 30, 2023, the Transfer Agent has contractually agreed to waive a portion of the fees payable to it by the Funds such that fees paid by the Funds do not exceed: (i) with respect to Columbia Acorn International, 0.04% of the average daily net assets of Class Inst2 shares of the Fund; (ii) with respect to Columbia Acorn USA, 0.08% of the average daily net assets of each share class other than Class Inst2 and Class Inst3 shares of the Fund; (iii) with respect to Columbia Acorn European Fund, 0.03% of the average daily net assets of Class Inst2 shares of the Fund; and (iv) with respect to Columbia Acorn International and Columbia Acorn European Fund, 0.00% of the average daily net assets of Class Inst3 shares of the Fund. These arrangements may be terminated at the sole discretion of the Board.

Portfolio Managers

The following provides additional information about the portfolio managers of the Investment Manager who are responsible for making the day-to-day investment decisions for the Funds. As described in the Management of the Fund — Primary Service Providers section of each Fund’s prospectus, the portfolio managers of the Investment Manager who are responsible for the Funds are:

Portfolio Managers of the Investment Manager

Portfolio Manager	Fund
Anwiti Bahuguna, Ph.D.	Columbia Thermostat Fund
Daniel Cole, CFA	Columbia Acorn Fund Columbia Acorn USA
John Emerson, CFA	Columbia Acorn Fund Columbia Acorn USA
Tae Han (Simon) Kim, CFA	Columbia Acorn International
Stephen Kusmierczak, CFA	Columbia Acorn European Fund Columbia Acorn International Select
Erika K. Maschmeyer, CFA	Columbia Acorn Fund Columbia Acorn USA
Sebastien Pigeon	Columbia Acorn European Fund
Alex Rivas	Columbia Thermostat Fund
Hans F. Stege	Columbia Acorn International Columbia Acorn International Select

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Compensation

Portfolio manager direct compensation is typically comprised of a base salary, and an annual incentive award that is paid either in the form of a cash bonus if the size of the award is under a specified threshold, or, if the size of the award is over a specified threshold, the award is paid in a combination of a cash bonus, an equity incentive award, and deferred compensation. Equity incentive awards are made in the form of Ameriprise Financial restricted stock or, for more senior employees, both Ameriprise Financial restricted stock and stock options. The investment return credited on deferred compensation is based on the performance of specified Columbia Funds, in most cases including the Columbia Funds the portfolio manager manages.

Base salary is typically determined based on market data relevant to the employee’s position, as well as other factors including internal equity. Base salaries are reviewed annually, and increases are typically given as promotional increases, internal equity adjustments, or market adjustments.

Under the annual incentive plan for investment professionals, awards are discretionary, and the amount of incentive awards for investment team members is variable based on (1) an evaluation of the investment performance of the investment team of which the investment professional is a member, reflecting the performance (and client experience) of the funds or accounts the investment professional manages and, if applicable, reflecting the individual’s work as an investment research analyst, (2) the results of a peer and/or management review of the individual, taking into account attributes such as team participation, investment process followed, communications, and leadership, and (3) the amount of aggregate funding of the plan determined by senior management of Columbia Threadneedle and Ameriprise Financial, which takes into account Columbia Threadneedle revenues and profitability, as well as Ameriprise Financial profitability, historical plan funding levels and other factors. Columbia Threadneedle revenues and profitability are largely determined by assets under management. In determining the allocation of incentive compensation to investment teams, the amount of assets and related revenues managed by the team is also considered. Individual awards are subject to a comprehensive risk adjustment review process to ensure proper reflection in remuneration of adherence to our controls and Code of Conduct.

Investment performance for a fund or other account is measured using a scorecard that compares account performance against benchmarks and/or peer groups. Account performance may also be compared to unaffiliated passively managed ETFs, taking into consideration the management fees of comparable passively managed ETFs, when available and as determined by the Investment Manager. Consideration is given to relative performance over the one-, three- and five-year periods, with the largest weighting on the three-year comparison. For individuals and teams that manage multiple strategies and accounts, relative asset size is a key determinant in calculating the aggregate score, with weighting typically proportionate to actual assets. For investment leaders who have group management responsibilities, another factor in their evaluation is an assessment of the group’s overall investment performance. Exceptions to this general approach to bonuses exist for certain teams and individuals.

Equity incentive awards are designed to align participants’ interests with those of the shareholders of Ameriprise Financial. Equity incentive awards vest over multiple years, so they help retain employees.

Deferred compensation awards are designed to align participants’ interests with the investors in the Columbia Funds and other accounts they manage. The value of the deferral account is based on the performance of Columbia Funds. Employees have the option of selecting from various Columbia Funds for their deferral account, however portfolio managers must (other than by strict exception) allocate a minimum of 25% of their incentive awarded through the deferral program to the Columbia Fund(s) they manage. Deferrals vest over multiple years, so they help retain employees.

For all employees the benefit programs generally are the same and are competitive within the financial services industry. Employees participate in a wide variety of plans, including options in Medical, Dental, Vision, Health Care and Dependent Spending Accounts, Life Insurance, Long Term Disability Insurance, 401(k), and a cash balance pension plan.

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Performance Benchmarks

Portfolio Manager	Performance Benchmarks
Anwiti Bahuguna (Columbia Thermostat Fund)	S&P 500® Index (primary equity benchmark), Bloomberg U.S. Aggregate Bond Index (primary debt benchmark) and the Blended Benchmark (an equally weighted custom composite of the Fund’s primary equity and debt benchmarks, established by the Investment Manager)
Daniel Cole (Columbia Acorn Fund)	Russell 2500 Growth Index (primary benchmark)
Daniel Cole (Columbia Acorn USA)	Russell 2500 Growth Index (primary benchmark)
John Emerson (Columbia Acorn Fund)	Russell 2500 Growth Index (primary benchmark)
John Emerson (Columbia Acorn USA)	Russell 2500 Growth Index (primary benchmark)
Tae Han (Simon) Kim (Columbia Acorn International)	MSCI ACWI ex USA SMID Cap Growth Index (Net) (primary benchmark) and MSCI ACWI ex USA SMID Cap Index (Net) (secondary benchmark)
Stephen Kusmierczak (Columbia Acorn European Fund)	MSCI AC Europe Small Cap Index (Net) (primary benchmark)
Stephen Kusmierczak (Columbia Acorn International Select)	MSCI ACWI ex USA Growth Index (Net) (primary benchmark) and MSCI ACWI ex USA Index (Net) (secondary benchmark)
Erika K. Maschmeyer (Columbia Acorn Fund)	Russell 2500 Growth Index (primary benchmark)
Erika K. Maschmeyer (Columbia Acorn USA)	Russell 2500 Growth Index (primary benchmark)
Sebastien Pigeon (Columbia Acorn European Fund)	MSCI AC Europe Small Cap Index (Net) (primary benchmark)
Alex Rivas (Columbia Thermostat Fund)	S&P 500® Index (primary equity benchmark), Bloomberg U.S. Aggregate Bond Index (primary debt benchmark) and the Blended Benchmark (an equally weighted custom composite of the Fund’s primary equity and debt benchmarks, established by the Investment Manager)
Hans F. Stege (Columbia Acorn International)	MSCI ACWI ex USA SMID Cap Growth Index (Net) (primary benchmark) and MSCI ACWI ex USA SMID Cap Index (Net) (secondary benchmark)
Hans F. Stege (Columbia Acorn International Select)	MSCI ACWI ex USA Growth Index (Net) (primary benchmark) and MSCI ACWI ex USA Index (Net) (secondary benchmark)

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Other Accounts Managed by the Portfolio Managers as of December 31, 2021

The following table shows the number and assets of other investment accounts (or portions of investment accounts) that the portfolio managers of the Investment Manager managed in addition to each Fund.

Fund	Portfolio Manager	Number and Type of Account*	Approximate Total Net Assets
Columbia Acorn European Fund	Stephen Kusmierczak	1 RIC	$480.20 million
		1 PIV	$16.68 million
		9 Other Accounts	$14.87 million
	Sebastien Pigeon	7 Other Accounts	$0.67 million
	John Emerson	5 RICs	$3.93 billion
		2 PIVs	$22.97 million
		12 Other Accounts	$21.82 million
Columbia Acorn Fund	Erika Maschmeyer	5 RICs	$3.93 billion
		1 PIV	$6.29 million
		9 Other Accounts	$21.50 million
	Daniel Cole	5 RICs	$6.16 billion
		2 PIVs	$144.66 million
		160 Other Accounts	$57.30 million
Columbia Acorn International	Simon Kim	1 RIC	$492.95 million
		4 Other Accounts	$0.35 million
	Hans Stege	1 RIC	$480.20 million
		8 Other Accounts	$0.78 million
Columbia Acorn International Select	Stephen Kusmierczak	1 RIC	$213.87 million
		1 PIV	$16.68 million
		9 Other Accounts	$14.87 million
	Hans Stege	1 RIC	$2.34 billion
		8 Other Accounts	$0.78 million
Columbia Acorn USA	Daniel Cole**	6 RICs	$8.54 billion
		2 PIVs	$117.60 million
		162 Other Accounts	$50.02 million
	John Emerson	5 RICs	$8.16 billion
		2 PIVs	$22.97 million
		12 Other Accounts	$21.82 million
	Erika Maschmeyer	5 RICs	$8.16 billion
		1 PIV	$6.29 million
		9 Other Accounts	$21.50 million
Columbia Thermostat Fund	Anwiti Bahuguna	20 RICs	$79.20 billion
		28 PIVs	$4.76 billion
		36 Other Accounts	$273.90 million
	Alex Rivas**	2 Other Accounts	$0.29 million

* “RIC” in this context refers to an SEC-registered investment company; “PIV” refers to a pooled investment vehicle.

** The portfolio manager began managing the Fund after its last fiscal year end; reporting information is provided as of March 31, 2022.

Accounts Managed by the Portfolio Managers for which the Advisory Fee is Based on Performance

Mr. Kusmierczak and Mr. Emerson co-manage the Wanger Socially Responsive Fund, a private investment fund with total assets of approximately $16.68 million as of December 31, 2021.

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Ownership of Securities

The table below shows the dollar ranges of shares of each Fund beneficially owned (as determined pursuant to Rule 16a-1(a)(2) under the 1934 Act) by its portfolio managers.

Portfolio Manager Ownership as of December 31, 2021

Portfolio Manager	Fund	Dollar Range of Equity Securities in the Fund Beneficially Owned
Anwiti Bahuguna	Columbia Thermostat Fund	$50,001 - $100,000
Daniel Cole	Columbia Acorn Fund	$100,001 - $500,000
	Columbia Acorn USA	—*
John Emerson	Columbia Acorn Fund	$100,001 - $500,000
	Columbia Acorn USA	$10,001 - $50,000
Tae Han (Simon) Kim	Columbia Acorn International	$100,001 - $500,000
Stephen Kusmierczak	Columbia Acorn European Fund	over $1 million
	Columbia Acorn International Select	over $1 million
Erika K. Maschmeyer	Columbia Acorn Fund	$100,001 - $500,000
	Columbia Acorn USA	$10,001 - $50,000
Sebastien Pigeon	Columbia Acorn European Fund	$10,001 - $50,000
Alex Rivas	Columbia Thermostat Fund	—*
Hans F. Stege	Columbia Acorn International	$10,001 - $50,000
	Columbia Acorn International Select	$10,001 - $50,000

* The portfolio manager began managing the Fund after its last fiscal year end; reporting information is provided as of March 31, 2022.

The Investment Manager’s Portfolio Managers and Potential Conflicts of Interests

Like other investment professionals with multiple clients, a Fund’s portfolio manager(s) may face certain potential conflicts of interest in connection with managing both the Fund and other accounts at the same time. The Investment Manager and the Funds have adopted compliance policies and procedures that attempt to address certain of the potential conflicts that portfolio managers face in this regard. Certain of these conflicts of interest are summarized below.

The management of accounts with different advisory fee rates and/or fee structures may raise potential conflicts of interest for a portfolio manager by creating an incentive to favor higher fee accounts.

Potential conflicts of interest also may arise when a portfolio manager has personal investments in other accounts that may create an incentive to favor those accounts. As a general matter and subject to the Investment Manager’s Code of Ethics and certain limited exceptions, the Investment Manager’s investment professionals do not have the opportunity to invest in client accounts, other than the Funds and the series of Wanger Advisors Trust.

A portfolio manager who is responsible for managing multiple funds and/or accounts may devote unequal time and attention to the management of those funds and/or accounts. The effects of this potential conflict may be more pronounced where funds and/or accounts managed by a particular portfolio manager have different investment strategies.

A portfolio manager may be able to select or influence the selection of the broker-dealers that are used to execute securities transactions for the Funds. A portfolio manager’s decision as to the selection of broker-dealers could produce disproportionate costs and benefits among the Funds and the other accounts the portfolio manager manages.

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A potential conflict of interest may arise when a portfolio manager buys or sells the same securities for a Fund and other accounts. On occasions when a portfolio manager considers the purchase or sale of a security to be in the best interests of a Fund as well as other accounts, the Investment Manager’s trading desk may, to the extent consistent with applicable laws and regulations, aggregate the securities to be sold or bought in order to obtain the best execution and lower brokerage commissions, if any. Aggregation of trades may create the potential for unfairness to a Fund or another account if a portfolio manager favors one account over another in allocating the securities bought or sold.

Typically the Investment Manager does not coordinate trading activities for accounts managed by the Investment Manager with Columbia Management or any other Affiliate with respect to accounts of Columbia Management (including the other Columbia Funds) or another Affiliate. As a result, it is possible that the Investment Manager, Columbia Management (including Fund portfolio managers that are employees of Columbia Management and portfolio managers of the other Columbia Funds) and other Affiliates may trade in the same instruments at the same time, in the same or opposite direction or in different sequence, which could negatively impact the prices paid by the Funds on such instruments.

“Cross trades,” in which a portfolio manager sells a particular security held by a Fund to another account (potentially saving transaction costs for both accounts), could involve a potential conflict of interest if, for example, a portfolio manager is permitted to sell a security from one account to another account at a higher price than an independent third party would pay. The Investment Manager and the Funds have adopted compliance procedures that provide that any transactions between a Fund and another account managed by the Investment Manager are to be made at an independent current market price, consistent with applicable laws and regulation.

Another potential conflict of interest may arise based on the different investment objectives and strategies of a Fund and other accounts managed by its portfolio manager(s). Depending on another account’s objectives and other factors, a portfolio manager may give advice to and make decisions for a Fund that may differ from advice given, or the timing or nature of decisions made, with respect to another account. A portfolio manager’s investment decisions are the product of many factors in addition to basic suitability for the particular account involved. Thus, a portfolio manager may buy or sell a particular security for certain accounts, and not for a Fund, even though it could have been bought or sold for the Fund at the same time. A portfolio manager also may buy a particular security for one or more accounts when one or more other accounts are selling the security (including short sales). There may be circumstances when a portfolio manager’s purchases or sales of portfolio securities for one or more accounts may have an adverse effect on other accounts, including the Funds.

A Fund’s portfolio manager(s) also may have other potential conflicts of interest in managing the Fund, and the description above is not a complete description of every conflict that could exist in managing the Fund and other accounts. Many of the potential conflicts of interest to which the Investment Manager’s portfolio managers are subject are essentially the same as or similar to the potential conflicts of interest related to the investment management activities of the Investment Manager and its affiliates. See Investment Advisory and Other Services — Other Roles and Relationships of Ameriprise Financial and its Affiliates — Certain Conflicts of Interest for more information about conflicts of interest, including those that relate to the Investment Manager and its affiliates.

To the extent a Fund invests in underlying funds, the Investment Manager will be subject to the potential conflicts of interest described in ABOUT THE FUNDS’ INVESTMENTS — Information Regarding Risks — Fund-of-Funds Risk. Management of a fund-of-funds, such as Columbia Thermostat Fund, differs from that of the other mutual funds. The portfolio management process is set forth in each Fund’s prospectus. The portfolio manager of a fund-of-funds is involved in determining the allocation of the fund-of-fund’s assets among underlying funds. Potential conflicts of interest for the portfolio manager of a fund-of-funds may be different than the potential conflicts of interest for portfolio managers who manage other types of funds because a fund-of-fund’s portfolio manager has an incentive to allocate assets to underlying funds managed by affiliates that receive fees for managing the underlying funds.

The Investment Manager and its affiliates may receive higher compensation as a result of the allocation of fund-of-fund assets to underlying funds with higher fees, including affiliated funds.

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In addition, a fund-of-funds portfolio manager may manage other accounts in a professional or personal capacity that include holdings that are similar to or the same as those held or purchased by the Funds. The Investment Manager has in place a Code of Ethics that is designed to address conflicts and that, among other things, imposes restrictions on the ability of portfolio managers and other “investment access persons” to invest in securities that may be recommended or traded in Fund and other client accounts. The Funds’ portfolio managers also may have other potential conflicts of interest in managing the Funds. Many of the potential conflicts of interest to which the Funds’ portfolio managers are subject are essentially the same or similar to the potential conflicts of interest related to the investment management activities of the Investment Manager and its affiliates.

The description above is not a complete description of every conflict that could exist in managing the Funds and other accounts. In addition, if the Investment Manager has engaged an Affiliate to provide portfolio management or other services pursuant to a personnel-sharing agreement or other inter-company arrangement, the individuals performing such services may be subject to conflicts of interest rules and codes of ethics of the Affiliate, which may differ from those of the Investment Manager.

The Administrator

CWAM (which is also the Investment Manager) serves as Administrator of the Funds.

Services Provided

Pursuant to the terms of the Administration Agreement, the Administrator provides certain administrative services to each Fund, including: (i) maintaining the books and records, including financial and corporate records, of the Trust, and providing pricing and bookkeeping services to the Funds; (ii) supervising the preparation and filing of registration statements, notices, reports, proxy statements, tax returns and other documents, as deemed necessary or desirable by the Trust; (iii) overseeing and assisting in the coordination of the performance of administrative and third party professional services rendered to the Funds, including the Funds’ securities lending agent; (iv) providing corporate secretarial services and data processing facilities and calculating and arranging for notice and payment of distribution to shareholders; (v) developing and implementing procedures to monitor each Fund’s compliance with regulatory requirements and with each Fund’s investment policies and restrictions; (vi) providing for the services of employees of the Administrator who may be appointed as officers of the Trust; and (vii) providing services to shareholders of the Funds. The Administration Agreement may be terminated by the Board or the Administrator upon 60 days written notice. The Administrator has the power under the Administration Agreement to delegate some or all of its responsibilities to others, at the Administrator’s expense. The Administrator retains responsibility for any services it delegates.

The Administrator has delegated a majority of its responsibilities under the Administration Agreement to Columbia Management as the Funds’ Sub-Administrator. The Sub-Administrator provides many of the above enumerated services to the Funds, including fund accounting services, and receives a fee from the Administrator for such services.

Administration Fee Rates and Fees Paid

The Administrator receives compensation for its administration services, which is computed daily and paid monthly as an annual percentage of the aggregate average daily net assets of the Trust at the annual rates shown in each Fund’s prospectus.

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The following chart shows the administration fees paid to the Administrator for the three most recently completed fiscal years.

Administration Fees Paid by the Funds

Fund	Fiscal Year Ended December 31, 2021		Fiscal Year Ended December 31, 2020		Fiscal Year Ended December 31, 2019
Columbia Acorn Fund
Administration Fee		$2,324,934		$2,013,589	$	2,095,088
Columbia Acorn International
Administration Fee		$1,179,111		$1,150,836	$	1,330,244
Columbia Acorn USA
Administration Fee		$156,104		$136,880		$149,987
Columbia Acorn International Select
Administration Fee		$232,872		$143,124		$65,714
Columbia Acorn European Fund
Administration Fee		$78,489		$40,533		$38,339
Columbia Thermostat Fund
Administration Fee		$972,231		$561,618		$342,180

The Administrator did not waive or reimburse any Fund’s administration fees for the fiscal years ended December 31, 2021, December 31, 2020 or December 31, 2019.

The Principal Underwriter/Distributor

Columbia Management Investment Distributors, Inc. (the Distributor) serves as the principal underwriter and distributor of the shares of the Funds. The Distributor is a wholly owned subsidiary of Ameriprise Financial. Its address is: 290 Congress Street, Boston, MA 02210.

Distribution Obligations

Pursuant to the Distribution Agreement, the Distributor, as agent, sells shares of the Funds on a continuous basis and transmits purchase and redemption orders that it receives to the Trust or the Transfer Agent. Additionally, the Distributor has agreed to use appropriate efforts to solicit orders for the sale of shares and to undertake advertising and promotion as it believes appropriate in connection with such solicitation. Pursuant to the Distribution Agreement, the Distributor, at its own expense, finances those activities which are primarily intended to result in the sale of shares of the Funds, including, but not limited to, advertising, compensation of underwriters, dealers and sales personnel, the printing of prospectuses to other than existing shareholders, and the printing and mailing of sales literature. The Distributor, however, may be compensated or reimbursed for all or a portion of such expenses to the extent permitted by the Distribution Plan adopted by the Trust pursuant to Rule 12b-1 under the 1940 Act.

See Investment Management and Other Services — Other Roles and Relationships of Ameriprise Financial and its Affiliates — Certain Conflicts of Interest for more information about conflicts of interest, including those that relate to the Investment Manager and its affiliates.

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The Distribution Agreement became effective with respect to each Fund after approval by the Board, and continues from year to year, provided that such continuation of the Distribution Agreement is specifically approved at least annually by (i) the Board, or (ii) a majority vote of the Funds’ outstanding securities, provided that in either instance, the continuance is also approved by the majority of the Independent Trustees who are not parties to the agreement, by vote cast in person at a meeting called for the purpose of voting such approval. The Distribution Agreement terminates automatically in the event of its assignment, and is terminable with respect to each Fund at any time without penalty by the Trust (by vote of the Board or by vote of a majority of the outstanding voting securities of the Fund) or by the Distributor on 60 days written notice.

Underwriting Commissions

The following table shows all commissions and other compensation received by the Distributor, as well as amounts the Distributor retained, after paying commissions and other expenses, during the Funds’ three most recent fiscal years.

	Sales Charges Paid to Distributor						Amount Retained by Distributor After Paying Commissions
	2021		2020		2019		2021		2020		2019
Columbia Acorn Fund	$	158,343	$	185,097	$	248,114	$	24,136	$	28,264	$	40,275
Columbia Acorn International	$	53,764	$	53,900	$	73,060	$	8,113	$	7,764	$	15,410
Columbia Acorn USA	$	13,772	$	19,070	$	46,539	$	2,045	$	2,306	$	7,496
Columbia Acorn International Select	$	34,425	$	45,827	$	65,033	$	5,015	$	6,613	$	10,385
Columbia Acorn European Fund	$	135,064	$	57,749	$	36,612	$	19,231	$	9,069	$	6,624
Columbia Thermostat Fund	$	1,252,623	$	1,604,016	$	288,944	$	206,886	$	241,095	$	44,933

Part of the sales charge may be paid to selling dealers who have agreements with the Distributor. The Distributor will retain the balance of the sales charge. At times the entire sales charge may be paid to selling dealers. See each Fund’s prospectus for amounts retained by financial intermediaries as a percentage of the offering price.

Distribution Plan

The Board has approved the Distribution Plan pursuant to Rule 12b-1 under the 1940 Act for each of the Funds’ Class A, Class C and Class R shares. Class Adv, Class Inst, Class Inst2, and Class Inst3 shares of the Funds do not pay distribution or service fees. Under the Distribution Plan, each Fund pays the Distributor monthly distribution and service fees, as applicable, at the annual rates described in the Fund’s prospectus. The Distributor may use the entire amount of such fees to defray the costs of commissions and service fees paid to Selling Agents and for certain other purposes. Since the distribution and service fees are payable regardless of the Distributor’s expenses, the Distributor may realize a profit from the fees. See the Funds’ prospectuses for details.

The Distribution Plan authorizes payments by the Funds to the Distributor and its affiliates (including the Investment Manager) with respect to the Funds’ Class A, Class C and Class R shares to the extent that such payments might be construed to be indirect financing of the distribution of those shares.

The Board believes the Distribution Plan could be a significant factor in the growth and retention of Fund assets resulting in a more advantageous expense ratio and increased investment flexibility which could benefit each class of Fund shareholders. The Distribution Plan will continue in effect from year to year so long as its continuance is specifically approved at least annually by a vote of the Trustees, including the Independent Trustees that have no direct or indirect financial interest in the operation of the Distribution Plan or in any agreements related to the Plan, by vote cast in person at a meeting called for the purpose of voting on the Distribution Plan. The Distribution Plan may not be amended to increase the fee materially without approval by vote of a majority of the outstanding voting securities of the relevant class of shares and all material amendments of the Plan must be approved by the Trustees in the manner described above. The Distribution Plan may be terminated at any time by vote of a majority of the Independent Trustees or by vote of a majority of the outstanding voting securities of the relevant class of shares.

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During the most recently completed fiscal year, the Distributor received distribution and service fees from the Funds for its services as reflected in the following table.

Distribution and Service Fees Paid by the Funds for the Fiscal Year Ended December 31, 2021

Fund	Class A Shares		Class C Shares		Class R Shares
Columbia Acorn Fund	$	2,470,521	$	362,402		—
Columbia Acorn International	$	724,440	$	139,535	$	17,201
Columbia Acorn USA	$	146,378	$	21,508		—
Columbia Acorn International Select	$	587,856	$	24,577		—
Columbia Acorn European Fund	$	137,142	$	58,318		—
Columbia Thermostat Fund	$	1,514,500	$	1,955,747		—

Other Roles and Relationships of Ameriprise Financial and its Affiliates — Certain Conflicts of Interest

As described above in the Investment Advisory and Other Services section of this SAI, and in the Management of the Fund — Primary Service Providers section of each Fund’s prospectus, the Investment Manager, Administrator, Sub-Administrator, Distributor and Transfer Agent, all affiliates of Ameriprise Financial, receive compensation from the Funds for the various services they provide to the Funds. Additional information as to the specific terms regarding such compensation is set forth in these affiliated service providers’ contracts with the Funds, each of which typically is included as an exhibit to Part C of the Funds’ registration statement.

In many instances, the compensation paid to the Investment Manager and other Ameriprise Financial affiliates for the services they provide to the Funds is based, in some manner, on the size of the Funds’ assets under management. As the size of the Funds’ assets under management grows, so does the amount of compensation paid to the Investment Manager and, as the case may be, other Ameriprise Financial affiliates for providing services to the Funds. This relationship between Fund assets and affiliated service provider compensation may create economic and other conflicts of interests of which Fund investors should be aware. Fund investors should also be aware that Fund assets may be used to compensate the Transfer Agent for payments made to Ameriprise and its affiliates for providing shareholder servicing or “sub-transfer agency” services. Many of these potential conflicts of interest, as well as additional ones, are discussed in detail below and also are addressed in other disclosure materials, including the Funds’ prospectuses. These conflicts of interest also are highlighted in account documentation and other disclosure materials of Ameriprise Financial affiliates that make available or offer the Columbia Funds as investments in connection with their respective products and services. In addition, the Investment Manager’s Form ADV, which it must file with the SEC as an investment adviser registered under the Investment Advisers Act of 1940, provides information about the Investment Manager’s business, assets under management, affiliates and potential conflicts of interest. Parts 1A and 2A of the Investment Manager’s Form ADV are available online through the SEC’s website at adviserinfo.sec.gov.

Additional actual or potential conflicts of interest and certain investment activity limitations that could affect the Funds may arise from the financial services activities of Ameriprise Financial and its affiliates, including, for example, the investment advisory/management services provided for clients and customers other than the Funds. Ameriprise Financial and its affiliates are engaged in a wide range of financial activities beyond the mutual fund-related activities of the Investment Manager, including, among others, broker-dealer (sales and trading), asset management, insurance and other financial activities. The broad range of financial services activities of Ameriprise Financial and its affiliates may involve multiple advisory, transactional, lending, financial and other interests in securities and other instruments, and in companies, that may be bought, sold or held by the Funds. The following describes certain actual and potential conflicts of interest that may be presented.

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Actual and Potential Conflicts of Interest Related to the Investment Advisory/Management Activities of Ameriprise Financial and its Affiliates in Connection With Other Funds, Advised/Managed Funds and Accounts

The Investment Manager, Ameriprise Financial and other affiliates of Ameriprise Financial may advise or manage funds and accounts other than the Funds. In this regard, Ameriprise Financial and its affiliates may provide investment advisory/management and other services to other advised/managed funds and accounts that are similar to those provided to the Funds. The Investment Manager and Ameriprise Financial’s other investment adviser affiliates (including, for example, Columbia Management, Columbia Cent CLO Advisers, LLC, Lionstone Partners, LLC and Threadneedle International Limited) will give investment advice to and make investment decisions for all advised/managed funds and accounts, including the Funds, as they believe to be in that fund’s and/or account’s best interests, consistent with their fiduciary duties. The Funds and the other advised/managed funds and accounts of Ameriprise Financial and its affiliates are separately and potentially divergently managed, and there is no assurance that any investment advice Ameriprise Financial and its affiliates give to other advised/managed funds and accounts will also be given simultaneously or otherwise to the Funds.

A variety of other actual and potential conflicts of interest may arise from the advisory relationships of the Investment Manager, Ameriprise Financial and other Ameriprise Financial affiliates with other clients and customers. Advice given to the Funds and/or investment decisions made for the Funds by the Investment Manager or other Ameriprise Financial affiliates may differ from, or may conflict with, advice given to and/or investment decisions made by the Investment Manager, Ameriprise Financial or other Ameriprise Financial affiliates for other advised/managed funds and accounts. As a result, the performance of the Funds may differ from the performance of other funds or accounts advised/managed by the Investment Manager, Ameriprise Financial or other Ameriprise Financial affiliates. Similarly, a position taken by Ameriprise Financial and its affiliates, including the Investment Manager, on behalf of other funds or accounts may be contrary to a position taken on behalf of the Funds. Moreover, Ameriprise Financial and its affiliates, including the Investment Manager, may take a position on behalf of other advised/managed funds and accounts, or for their own proprietary accounts, that is adverse to companies or other issuers in which the Funds are invested. Also, the Investment Manager may take a position on behalf of certain Funds that is adverse to that of certain other Funds or accounts advised/managed by the Investment Manager, Ameriprise Financial or other Ameriprise Financial affiliates. For example, certain Funds may hold equity securities of a company while certain other Funds or accounts advised/managed by the Investment Manager, Ameriprise Financial or other Ameriprise Financial affiliates may hold debt securities of the same company – certain Funds may even own different debt instruments of the same issuer, where certain Funds own subordinated (junior) debt of an issuer and certain other Funds own senior debt of the same issuer, which presents a conflict of interest to the Investment Manager because junior debt is less of a priority than senior debt in terms of repayments. Senior debt is often secured and is more likely to be paid back while subordinated debt is not secured and is more of a risk. If the portfolio company were to experience financial difficulties, it might be in the best interest of certain Funds for the company to reorganize while the interests of certain other Funds or accounts advised/managed by the Investment Manager, Ameriprise Financial or other Ameriprise Financial affiliates might be better served by the liquidation of the company. Conflicts are magnified with respect to issuers that become insolvent. It is possible that in connection with an insolvency, bankruptcy, reorganization, or similar proceeding, certain Funds will be limited (by applicable law, courts or otherwise) in the positions or actions it will be permitted to take due to other interests held or actions or positions taken by certain other Funds or accounts advised/managed by the Investment Manager, Ameriprise Financial or other Ameriprise Financial affiliates. Certain Funds may invest in offerings of securities the proceeds of which may be used to repay debt obligations held by certain other Funds or accounts advised/managed by the Investment Manager, Ameriprise Financial or other Ameriprise Financial affiliates. The latter’s interest in having the debt repaid creates a conflict of interest. These types of conflicts of interest could arise as the result of circumstances that cannot be generally foreseen within the broad range of investment advisory/management activities in which Ameriprise Financial and its affiliates engage. The Investment Manager has adopted policies and procedures designed to address these types of conflicts of interest among the Funds and other Funds and accounts advised by the Investment Manager, Ameriprise Financial and other affiliates of Ameriprise Financial.

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Investment transactions made on behalf of other funds or accounts advised/managed by the Investment Manager or other Ameriprise Financial affiliates also may have a negative effect on the value, price or investment strategies of the Funds. For example, this could occur if another advised/managed fund or account implements an investment decision ahead of, or at the same time as, the Funds and causes the Funds to experience less favorable trading results than they otherwise would have experienced based on market liquidity factors. In addition, the other funds and accounts advised/managed by the Investment Manager and other Ameriprise Financial affiliates, including the other Columbia Funds and accounts of Ameriprise Financial and its affiliates, may have the same or very similar investment objective and strategies as the Funds. In this situation, the allocation of, and competition for, investment opportunities among the Funds and other funds and/or accounts advised/managed by the Investment Manager or other Ameriprise Financial affiliates may create conflicts of interest especially where, for example, limited investment availability is involved. The Investment Manager has adopted policies and procedures addressing the allocation of investment opportunities among the Funds and other funds and accounts advised by the Investment Manager and other affiliates of Ameriprise Financial. For more information, see Investment Advisory and Other Services — The Investment Manager and Investment Advisory Services — Portfolio Managers — The Investment Manager’s Portfolio Managers and Potential Conflicts of Interests.

Sharing of Information among Advised/Managed Accounts

Ameriprise Financial and its affiliates also may possess information that could be material to the management of a Fund and may not be able to, or may determine not to, share that information with the Fund, even though the information might be beneficial to the Fund. This information may include actual knowledge regarding the particular investments and transactions of other advised/managed funds and accounts, as well as proprietary investment, trading and other market research, analytical and technical models, and new investment techniques, strategies and opportunities. Depending on the context, Ameriprise Financial and its affiliates generally will have no obligation to share any such information with the Funds. In general, employees of Ameriprise Financial and its affiliates, including the portfolio managers of the Investment Manager, will make investment decisions without regard to information otherwise known by other employees of Ameriprise Financial and its affiliates, and generally will have no obligation to access any such information and may, in some instances, not be able to access such information because of legal and regulatory constraints or the internal policies and procedures of Ameriprise Financial and its affiliates. For example, if the Investment Manager or another Ameriprise Financial affiliate, or their respective employees, come into possession of non-public information regarding another advised/managed fund or account, they may be prohibited by legal and regulatory constraints, or internal policies and procedures, from using that information in connection with transactions made on behalf of the Funds. For more information, see Investment Advisory and Other Services — The Investment Manager and Investment Advisory Services — Portfolio Managers — The Investment Manager’s Portfolio Managers and Potential Conflicts of Interests.

Soft Dollar Benefits

Certain products and services, commonly referred to as “soft dollar services” (including, to the extent permitted by law, research reports, economic and financial data, financial publications, proxy analysis, computer databases and other research-oriented materials), that the Investment Manager may receive in connection with brokerage services provided to a Fund may have the effect of disproportionately benefiting other advised/managed funds or accounts. This could happen because of the relative amount of brokerage services provided to a Fund as compared to other advised/managed funds or accounts, as well as the relative compensation paid by a Fund. For more information, see Brokerage Allocation and Other Practices — Brokerage Commissions.

Services Provided to Other Advised/Managed Accounts

Ameriprise Financial and its affiliates also may act as an investment adviser, investment manager, administrator, transfer agent, custodian, trustee, broker-dealer, agent, or in another capacity, for advised/managed

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funds and accounts other than the Funds, and may receive compensation for acting in such capacity. This compensation that the Investment Manager, Distributor and Transfer Agent and other Ameriprise Financial affiliates receive could be greater than the compensation Ameriprise Financial and its affiliates receive for acting in the same or similar capacity for the Funds. In addition, the Investment Manager, Distributor and Transfer Agent and other Ameriprise Financial affiliates may receive other benefits, including enhancement of new or existing business relationships. This compensation and/or the benefits that Ameriprise Financial and its affiliates may receive from other advised/ managed funds and accounts and other relationships could potentially create incentives to favor other advised/managed funds and accounts over the Funds. Trades made by Ameriprise Financial and its affiliates for the Funds may be, but are not required to be, aggregated with trades made for other funds and accounts advised/managed by the Investment Manager and other Ameriprise Financial affiliates. If trades are aggregated among the Funds and those other funds and accounts, the various prices of the securities being traded may be averaged, which could have the potential effect of disadvantaging the Funds as compared to the other funds and accounts with which trades were aggregated.

Proxy Voting

Although the Investment Manager endeavors to make all proxy voting decisions with respect to the interests of the Funds for which it is responsible in accordance with its proxy voting principles and procedures, the Investment Manager’s proxy voting decisions with respect to a Fund’s portfolio securities may nonetheless benefit other advised/managed funds and accounts, and/or clients, of Ameriprise Financial and its affiliates. The Investment Manager has adopted proxy voting principles and procedures that are designed to provide that all proxy voting is done in the best interests of its clients, including the Funds, without any resulting benefit or detriment to the Investment Manager and/or its affiliates, including Ameriprise Financial and its affiliates. For more information about the Investment Manager’s proxy voting policies and procedures, see Investment Advisory and Other Services — Proxy Voting Policies and Procedures.

Certain Trading Activities

The directors/trustees, officers and employees of Ameriprise Financial and its affiliates may buy and sell securities or other investments for their own accounts, and in doing so may take a position that is adverse to the Funds. In order to reduce the possibility that such personal investment activities of the directors/trustees, officers and employees of Ameriprise Financial and its affiliates will materially adversely affect the Funds, Ameriprise Financial and its affiliates have adopted policies and procedures, and the Funds, the Board, the Investment Manager and the Distributor have each adopted a Code of Ethics that addresses such personal investment activities. For more information, see Investment Advisory and Other Services — Codes of Ethics.

Affiliate Transactions

Subject to applicable legal and regulatory requirements, a Fund may enter into transactions in which Ameriprise Financial and/or its affiliates, or companies that are deemed to be affiliates of a Fund because of, among other factors, their or their affiliates’ ownership or control of shares of the Fund, may have an interest that potentially conflicts with the interests of the Fund. For example, an affiliate of Ameriprise Financial may sell securities to a Fund from an offering in which it is an underwriter or that it owns as a dealer, subject to applicable legal and regulatory requirements.

Certain Investment Limitations

Regulatory and other restrictions may limit a Fund’s investment activities in various ways. For example, certain securities may be subject to ownership limitations due to regulatory limits on investments in certain industries (such as, for example, banking and insurance) and markets (such as emerging or international markets), or certain transactions (such as those involving certain derivatives or other instruments) or mechanisms imposed by certain issuers (such as, among others, poison pills). Certain of these restrictions may impose limits

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on the aggregate amount of investments that may be made by affiliated investors in the aggregate or in individual issuers. In these circumstances, the Investment Manager may be prevented from acquiring securities for a Fund (that it might otherwise prefer to acquire) if the acquisition would cause the Fund and its affiliated investors to exceed an applicable limit. These types of regulatory and other applicable limits are complex and vary significantly in different contexts including, among others, from country to country, industry to industry and issuer to issuer. The Investment Manager has policies and procedures designed to monitor and interpret these limits. Nonetheless, given the complexity of these limits, the Investment Manager and/or its affiliates may inadvertently breach these limits, and a Fund may therefore be required to sell securities that it might otherwise prefer to hold in order to comply with such limits. In addition, aggregate ownership limitations could cause performance dispersion among funds and accounts managed by the Investment Manager with similar investment objectives and strategies and portfolio management teams. For example, if further purchases in an issuer are restricted due to regulatory or other reasons, a portfolio manager would not be able to acquire securities or other assets of an issuer for a new fund that may already be held by other funds and accounts with the same/similar investment objectives and strategies that are managed by the same portfolio management team. The Investment Manager may also choose to limit purchases in an issuer to a certain threshold for risk management purposes. If the holdings of the Investment Manager’s affiliates are included in that limitation, a Fund may be more limited in its ability to purchase a particular security or other asset than if the holdings of the Investment Manager’s affiliates had been excluded from the limitation. At certain times, a Fund may be restricted in its investment activities because of relationships that an affiliate of the Fund, which may include Ameriprise Financial and its affiliates, may have with the issuers of securities. This could happen, for example, if a Fund desired to buy a security issued by a company for which Ameriprise Financial or an affiliate serves as underwriter. A Fund may also be limited in certain investments because Ameriprise Financial, a financial holding company, is subject to certain banking regulatory requirements which may in some cases apply to the Investment Manager’s investments for the funds and accounts, including the Funds, it manages. Also, Ameriprise Financial issues various securities from time to time, including common stock. With the exception of Funds passively managed to track an unaffiliated index in which an Ameriprise Financial security is included, the Funds do not invest in Ameriprise Financial securities. Therefore, actively managed Funds and passively managed funds that seek to track an affiliated index will not hold any Ameriprise Financial securities even if such securities are included in an index used by the Fund for performance comparison and/or tracking purposes. Accordingly, the performance of such Funds versus their index will likely differ. In any of these scenarios, a Fund’s inability to participate (or participate further) in a particular investment, despite a portfolio manager’s desire to so participate, may negatively impact Fund performance. The internal policies and procedures of Ameriprise Financial and its affiliates covering these types of restrictions and addressing similar issues also may at times restrict a Fund’s investment activities. See also About the Funds’ Investments — Certain Investment Activity Limits.

Actual and Potential Conflicts of Interest Related to Ameriprise Financial and its Affiliates’ Non-Advisory Relationships with Clients and Customers other than the Funds

The financial relationships that Ameriprise Financial and its affiliates may have with companies and other entities in which a Fund may invest can give rise to actual and potential conflicts of interest. Subject to applicable legal and regulatory requirements, a Fund may invest (a) in the securities of Ameriprise Financial and/or its affiliates and/or in companies in which Ameriprise Financial and its affiliates have an equity, debt or other interest, and/or (b) in the securities of companies held by other Columbia Funds. The purchase, holding and sale of such securities by a Fund may enhance the profitability and the business interests of Ameriprise Financial and/or its affiliates and/or other Columbia Funds. There also may be limitations as to the sharing with the Investment Manager of information derived from the non-investment advisory/management activities of Ameriprise Financial and its affiliates because of legal and regulatory constraints and internal policies and procedures (such as information barriers and ethical walls). Because of these limitations, Ameriprise Financial and its affiliates generally will not share information derived from its non-investment advisory/management activities with the Investment Manager.

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Actual and Potential Conflicts of Interest Related to Ameriprise Financial Affiliates’ Marketing and Use of the Columbia Funds as Investment Options

Ameriprise Financial and its affiliates also provide a variety of products and services that, in some manner, may utilize the Columbia Funds as investment options. For example, the Columbia Funds may be offered as investments in connection with brokerage and other securities products offered by Ameriprise Financial and its affiliates, and may be utilized as investments in connection with fiduciary, investment management and other accounts offered by affiliates of Ameriprise Financial, as well as for other Columbia Funds structured as “funds of funds.” The use of the Columbia Funds in connection with other products and services offered by Ameriprise Financial and its affiliates may introduce economic and other conflicts of interest. These conflicts of interest are highlighted in account documentation and other disclosure materials for the other products and services offered by Ameriprise Financial and its affiliates.

Ameriprise Financial and its affiliates, including the Investment Manager, may make payments to their affiliates in connection with the promotion and sale of the Funds’ shares, in addition to the sales-related and other compensation that these parties may receive from the Funds. As a general matter, personnel of Ameriprise Financial and its affiliates do not receive compensation in connection with their sales or use of the Funds that is greater than that paid in connection with their sales of other comparable products and services. Nonetheless, because the compensation that the Investment Manager and other affiliates of Ameriprise Financial may receive for providing services to the Funds is generally based on the Funds’ assets under management and those assets will grow as shares of the Funds are sold, potential conflicts of interest may exist. See Brokerage Allocation and Other Practices — Additional Financial Intermediary Payments for more information.

Actual or Potential Conflicts of Interest Related to Affiliated Indexes

Columbia Management and its affiliates may develop, own and operate stock market and other indexes (each, an Affiliated Index) based on investment and trading strategies developed by Columbia Management and/or its affiliates (Affiliated Index Strategies). Some of the ETFs for which Columbia Management acts as investment adviser (the Affiliated Index ETFs) seek to track the performance of the Affiliated Indexes. Columbia Management and/or its affiliates may, from time to time, manage other funds or accounts that invest in these Affiliated Index ETFs. In the future, Columbia Management and/or its affiliates may manage client accounts that track the same Affiliated Indexes used by the Affiliated Index ETFs or which are based on the same, or substantially similar, Affiliated Index Strategies that are used in the operation of the Affiliated Indexes and the Affiliated Index ETFs. Similar to third-party (un-affiliated) indexes, Affiliated Indexes are subject to Office of Foreign Assets Control and other regulatory restrictions, which could impact the eligible components of such Indexes. The operation of the Affiliated Indexes, the Affiliated Index ETFs and other accounts managed in this manner may give rise to potential conflicts of interest.

For example, any accounts managed by Columbia Management and/or its affiliates that seek to track the same Affiliated Indexes may engage in purchases and sales of securities at different times. These differences may result in certain accounts having more favorable performance relative to that of the Affiliated Index or other accounts that seek to track the Affiliated Index. Other potential conflicts include (i) the potential for unauthorized access to Affiliated Index information, allowing Affiliated Index changes that benefit Columbia Management and/or its affiliates or other accounts managed by Columbia Management and/or its affiliates and not the clients in the accounts seeking to track the Affiliated Index, and (ii) the manipulation of Affiliated Index pricing to present the performance of accounts seeking to track the Affiliated Index, or the firm’s tracking ability, in a preferential light.

Columbia Management has adopted policies and procedures that are designed to address potential conflicts that may arise in connection with the operation of the Affiliated Indexes, the Affiliated Index ETFs and other accounts.

To the extent it is intended that an account managed by Columbia Management and/or its affiliates seeks to track an Affiliated Index, the account may not match (performance or holdings), and may vary substantially

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from, such index for any period of time. An account that seeks to track an index may purchase, hold and sell securities at times when another client would not do so. Columbia Management and its affiliates do not guarantee that any tracking error targets will be achieved. Accounts managed by Columbia Management and/or its affiliates that seek to track an index may be negatively impacted by errors in the index, either as a result of calculation errors, inaccurate data sources or otherwise. Columbia Management and its affiliates do not guarantee the timeliness, accuracy and/or completeness of an index and are not responsible for errors, omissions or interruptions in the index (including when Columbia Management or an affiliate acts as the index provider) or the calculation thereof (including when Columbia Management or an affiliate acts as the calculation agent).

Columbia Management and its affiliates are not obligated to license the Affiliated Indexes to clients or other third-parties.

Other Service Providers

The Transfer Agent

Columbia Management Investment Services Corp. acts as Transfer Agent for each Fund’s shares and can be contacted at P.O. Box 219104, Kansas City, MO 64121-9104. The Transfer Agent is a subsidiary of Ameriprise Financial. Under the Transfer Agency Agreement, the Transfer Agent is responsible for providing transfer agency, dividend disbursing and shareholder services to the Funds for which the Funds pay transfer agency fees. The Transfer Agent has engaged DST to provide certain services and assist the Transfer Agent is carrying out its duties. DST is located at 2000 Crown Colony Drive, Quincy, MA 02169. In addition, the Transfer Agent enters into agreements with various financial intermediaries through which investors may hold Fund shares, including Ameriprise Financial and its affiliates. These intermediaries also may provide shareholder services (Additional Shareholder Services) for which they are compensated by the Transfer Agent, which is in turn compensated by the Funds as described below. Additional Shareholder Services may include sub-accounting, sub-transfer agency, participant recordkeeping, shareholder or participant reporting, shareholder or participant transaction processing, shareholder or participant tax monitoring and reporting and/or the provision of call center support and other customer services. For more information, see Brokerage Allocation and Other Practices — Additional Shareholder Servicing Payments.

The Funds pay the Transfer Agent an annual fee payable monthly that varies by account type (on a per account or asset-based basis) based on the cost of servicing the Funds. In addition, subject to certain limitations and except with respect to Class Inst3 shares, the Funds pay a fee for the Additional Shareholder Services provided by financial intermediaries who maintain shares through omnibus or networked accounts in amounts that vary by share class and with the distribution channel, type of intermediary and type of services provided.

With respect to Class Inst2 shares of each Fund, total annual compensation payable to the Transfer Agent may not exceed 0.07% of the average daily net assets of the class. With respect to Class Inst3 shares of each Fund, total annual compensation payable to the Transfer Agent may not exceed 0.02% of the average daily net assets of the class. For more information on arrangements regarding fees paid by the Funds to the Transfer Agent, see The Investment Advisory and Other Services — Investment Manager and Investment Advisory Services — Fee and Expense Limitations — Agreements of the Investment Manager and its Affiliates.

The Funds compensate the Transfer Agent for certain out-of-pocket expenses as approved by the Board from time to time. Transfer agency costs for each Fund are calculated separately for each of (i) Class Inst2 shares, (ii) Class Inst3 shares, and (iii) all other share classes, provided that expenses may be allocated to a particular share class if they are actually incurred in a divergent amount by that share class or that share class receives services of a different kind or to a different degree than other share classes.

The fees paid to the Transfer Agent may be changed by the Board without shareholder approval.

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Except with respect to Class Inst2 shares and Class Inst3 shares, the Funds compensate the Transfer Agent for payments made to financial intermediaries for providing Additional Shareholder Services as follows:

Financial Intermediary Distribution Channel	Fee Rate
Retirement	up to 0.18% of Fund assets held by intermediaries or platforms charging an asset-based fee, or $18 per account held by intermediaries or platforms charging a per account fee
Fund supermarket transaction fee (TF)	up to 0.12% of Fund assets held by intermediaries or platforms charging an asset-based fee, or $16 per account held for intermediaries or platforms charging a per account fee
Fund supermarket no- transaction fee (NTF)	up to 0.18% of Fund assets held by intermediaries or platforms charging an asset-based fee, or $18 per account held by intermediaries or platforms charging a per account fee
Bank	up to 0.10% of Fund assets held by intermediaries or platforms charging an asset-based fee, or $20 per account held by intermediaries or platforms charging a per account fee
Broker-dealer	up to 0.13% of Fund assets held by intermediaries or platforms charging an asset-based fee, or $16 per account held by intermediaries or platforms charging a per account fee

These limits are applied by each individual intermediary at the level of the underlying customer accounts maintained and serviced by the intermediary, not at the level of the intermediary omnibus account maintained and serviced by the Transfer Agent, and not in the aggregate by distribution channel. For Class Inst2 shares, fees for Additional Shareholder Services are subject to an annual cap of 0.05% of the aggregate value of the Fund’s shares maintained in omnibus accounts. Class Inst3 shares do not pay fees for Additional Shareholder Services.

The Transfer Agent does not pay financial intermediaries for Additional Shareholder Services, and the Funds do not compensate the Transfer Agent for, any Additional Shareholder Services provided by financial intermediaries with respect to Class Inst3 shares. Amounts in excess of those paid by a Fund are borne by the Distributor, the Investment Manager and/or their affiliates. For more information about payments made to financial intermediaries, see Brokerage Allocation and Other Practices — Additional Shareholder Servicing Payments and Brokerage Allocation and Other Practices — Additional Payments to Financial Intermediaries.

The Transfer Agent may also retain as additional compensation for its services all of its revenues for fees for wire, telephone and redemption orders, IRA trustee agent fees and account transcripts due the Transfer Agent from shareholders of the Fund and interest (net of bank charges) earned with respect to the balances in accounts the Transfer Agent maintains in connection with its services to the Funds.

The Custodian

JPMorgan, 1 Chase Manhattan Plaza, New York, New York 10005, is the Custodian of the Funds’ assets. It is responsible for holding all securities and cash of the Funds, receiving and paying for securities purchased, delivering against payment securities sold, receiving and collecting income from investments and performing other administrative duties, all as directed by authorized persons of the Funds. The Investment Manager and Columbia Management supervise JPMorgan in such matters as the purchase and sale of portfolio securities. Portfolio

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securities purchased in the United States are maintained in the custody of JPMorgan or other domestic banks or depositories. Portfolio securities purchased outside of the United States are maintained in the custody of foreign banks and trust companies who are members of JPMorgan’s foreign depository and foreign sub-custodial network.

With respect to foreign depositories and foreign sub-custodians, there can be no assurance that a Fund, and the value of its shares, will not be adversely affected by acts of foreign governments, financial or operational difficulties of the foreign sub-custodians, difficulties and costs of obtaining jurisdiction over, or enforcing judgments against, the foreign sub-custodians or application of foreign law to a Fund’s foreign sub-custodial arrangements. Accordingly, an investors should recognize that the noninvestment risks involved in holding assets abroad are greater than those associated with holding assets in the U.S.

The Funds may invest in obligations of JPMorgan and may purchase securities from or sell securities to JPMorgan.

Independent Registered Public Accounting Firm

PricewaterhouseCoopers LLP, located at 45 South Seventh Street, Suite 3400, Minneapolis, MN 55402, serves as the Funds’ independent registered public accounting firm, providing audit services and assistance and consultation in connection with the review of various SEC filings. The report of the Funds’ independent registered public accounting firm and the audited financial statements included in the Funds’ annual report to shareholders dated December 31, 2021 are incorporated herein by reference. No other part of the annual report is incorporated by reference herein. The audited financial statements incorporated by reference into the Funds’ prospectuses and this SAI have been so incorporated in reliance upon the report of the independent registered public accounting firm, given on its authority as an expert in auditing and accounting.

Counsel

Perkins Coie LLP serves as counsel to the Funds. Faegre Drinker Biddle & Reath LLP serves as counsel to the Independent Trustees. Perkins Coie LLP is located at 700 13^th Street, N.W., Suite 800, Washington, DC 20005. Faegre Drinker Biddle & Reath LLP is located at One Logan Square, Suite 2000, Philadelphia, PA 19103.

Securities Lending Agent

GSAL, 125 High Street, Oliver Street Tower, Suite 1700, Boston, MA 02110, is the Funds’ securities lending agent. GSAL is responsible, among other things for: entering into and maintaining securities loan agreements with borrowers; negotiating fees with borrowers; delivering securities to borrowers; receiving collateral from borrowers in connection with loans; and investing cash collateral in accordance with instructions received from the Investment Manager. See About the Funds’ Investments — Lending Securities for more information about the Funds’ securities lending program.

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The following table provides information on the income and fees associated with the Funds’ securities lending activities during the Funds’ most recent fiscal year. As used in the table below, the term “revenue split” refers to the share of revenue generated by the Funds’ securities lending program that is paid to GSAL.

Securities Lending Activities as of December 31, 2021
	Columbia Acorn Fund		Columbia Acorn International		Columbia Acorn USA		Columbia Acorn International Select		Columbia Acorn European Fund		Columbia Thermostat Fund		Columbia Acorn Trust
Gross income from securities lending activities (including income from cash collateral reinvestment)	$	2,709,320	$	438,985	$	232,548	$	32,765	$	4,909		—	$	3,418,527
Fees and/or compensation for securities lending activities and related services
Fees paid to GSAL from revenue split	$	255,515	$	41,019	$	21,522	$	3,006	$	419		—	$	321,481
Fees paid for cash collateral management (including fees deducted from the third-party institutional money market fund in which collateral is invested)	$	140,988	$	30,730	$	16,488	$	2,704	$	718		—	$	191,628
Administrative fees not included in revenue split		—		—		—		—		—		—		—
Indemnification fee not included in revenue split		—		—		—		—		—		—		—
Rebates paid to borrowers		—		—		—		—		—		—		—
Other fees not included in revenue split		—		—		—		—		—		—		—
Aggregate fees/ compensation for securities lending activities	$	396,503	$	71,749	$	38,010	$	5,710	$	1,137		—	$	513,109
Net income from securities lending activities	$	2,312,817	$	367,236	$	194,538	$	27,055	$	3,772		—	$	2,905,418

Codes of Ethics

The Funds, the Investment Manager and the Distributor have adopted Codes of Ethics pursuant to the requirements of the 1940 Act, including Rule 17j-1 under the 1940 Act. These Codes of Ethics permit personnel subject to the Codes of Ethics to invest in securities, including securities that may be bought or held by the Funds. These Codes of Ethics are included as exhibits to Part C of the Funds’ registration statement. These Codes of Ethics can be obtained by calling the SEC at 202.551.8090; they also are available on the SEC’s website at sec.gov, and may be obtained, after paying a duplicating fee, by electronic request to publicinfo@sec.gov.

Proxy Voting Principles and Procedures

General. The Funds have delegated to the Investment Manager the responsibility to vote proxies relating to portfolio securities held by the Funds. In deciding to delegate this responsibility to the Investment Manager, the Board reviewed the policies adopted by the Investment Manager. These include the procedures that the Investment Manager follows when a vote presents a conflict between the interests of the Funds and their shareholders and the Investment Manager and its affiliates.

The Investment Manager’s policy is to vote all proxies for Fund securities in a manner considered by the Investment Manager to be in the best economic interests of its clients, including the Funds, without regard to any benefit or detriment to the Investment Manager, its employees or its affiliates. The best economic interests of clients is defined for this purpose as the interest of enhancing or protecting the value of client accounts, as the Investment Manager determines in its discretion. The Investment Manager endeavors to vote all proxies of which it becomes aware prior to the vote deadline; provided, however, that in certain circumstances the Investment Manager may refrain from voting securities. For instance, the Investment Manager may refrain from voting foreign securities if it determines that the costs of voting outweigh the expected benefits of voting and typically will not vote securities if voting would impose trading restrictions.

The Board may, in its discretion, vote proxies for the Funds. For instance, the Board may determine to vote on matters that may present a material conflict of interest to the Investment Manager.

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Oversight. The operation of the Investment Manager’s proxy voting policy and procedures is overseen by a committee (the Proxy Policy Committee) that includes senior investment and non-investment personnel. The Proxy Policy Committee has the responsibility to review, at least annually, the Investment Manager’s proxy voting policies to ensure consistency with internal policies, regulatory requirements, conflicts of interest and client disclosures. The Proxy Policy Committee also oversees the administration and implementation of the proxy voting policy and procedures. The Board reviews on an annual basis, or more frequently as determined appropriate, the Investment Manager’s administration of the proxy voting process.

Corporate Governance and Proxy Voting Principles (the Principles). The Investment Manager has adopted the Principles, which set out the Investment Manager’s views on key issues and the broad principles shaping its approach, as well as the types of related voting action the Investment Manager may take. The Principles also provide indicative examples of key guidelines used in any given region, which illustrate the standards against which voting decisions are considered. The Investment Manager has adopted voting stances that align with the Principles and will generally vote in accordance with such voting stances. When proposals are not covered by the voting stances or a voting determination must be made on a case-by-case basis, a portfolio manager will make the voting determination based on his or her determination of the clients’ best economic interests. The Funds’ portfolio managers may determine to vote differently from the voting stances on particular proposals in the event it determines that doing so is in the clients’ best economic interests. In such a case, the portfolio manager shall consider the specific investment (and other) goals of a Fund in determining the best economic interest of the Fund and may take into account, as he or she deems appropriate, a wide array of factors relating to the matter under consideration, including for example the nature of the proposal, the company involved, and the portfolio manager’s experience with and views regarding the company’s management. The Funds’ portfolio managers may also consider the voting recommendations of analysts, other portfolio managers, and affiliates and information obtained from outside resources, including one or more third party research providers. In such event, the reasons for such vote must be documented to the Proxy Policy Committee, including verification that the portfolio manager is not aware of any material conflict of interest existing with respect to such proxy proposal. Because portfolio managers may have different opinions on matters to be voted on, and the Funds they manage may have different investment or other goals, different Funds may cast different votes on a topic at the same shareholder meeting. In addition, the Proxy Policy Committee may determine proxy votes when proposals require special consideration.

Addressing Conflicts of Interest. The Investment Manager seeks to address potential material conflicts of interest by voting in accordance with predetermined voting stances that align with the Principles. In addition, if the Investment Manager determines that a material conflict of interest exists, the Investment Manager will invoke one or more of the following conflict management practices: (i) causing the proxies to be voted in accordance with the recommendations of an independent third party (which may be the Investment Manager’s proxy voting administrator or research provider); (ii) causing the proxies to be delegated to an independent third party (which may be the Investment Manager’s proxy voting administrator or research provider); and (iii) in infrequent cases, forwarding the proxies to the Board to vote the proxies for the Funds. CWAM employees are prohibited from voting on any proposal with respect to which they have a conflict of interest by reason of a direct relationship with the issuer or other party affected by a given proposal. Persons making recommendations to the Proxy Policy Committee or its members are required to disclose to the Proxy Policy Committee any relationship with a party making a proposal or other matter known to the person that would create a potential conflict of interest.

Voting Proxies of Affiliated Underlying Funds. Columbia Thermostat Fund invests in shares of other Columbia Funds (“underlying funds”) and may own substantial portions of these underlying funds. Columbia Thermostat Fund will typically vote proxies of the underlying funds in the same proportion as the vote of all other holders of the underlying fund’s shares, unless the Board otherwise instructs.

Administration of the Proxy Voting Policy. The Investment Manager has engaged Columbia Management to administer the proxy voting policy and implement the Principles for the Funds. Institutional Shareholder Services Inc., a third-party vendor, assists in this administration and implementation and provides recordkeeping

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and vote disclosure services. Typically, Institutional Shareholder Services Inc. populates ballots for issuers deemed to present potential material conflicts of interest in accordance with predetermined voting stances, as described above under Addressing Conflicts of Interest. Both Institutional Shareholder Services Inc. and Glass Lewis & Company, LLC provide proxy research services for the Investment Manager’s use.

Additional Information. Information regarding how the Funds voted proxies relating to portfolio securities during the most recent twelve month period ended June 30 will be available by August 31 of this year free of charge: (i) through the Columbia Funds’ website at columbiathreadneedleus.com and/or (ii) on the SEC’s website at www.sec.gov. For a copy of the Investment Manager’s Principles in effect on the date of this SAI, see Appendix B to this SAI.

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FUND GOVERNANCE

The Board

The following table provides basic information about the Trustees, including their names, the date each was first elected or appointed to office, the principal business occupations of each during at least the last five years and other directorships held. Each Trustee serves a term of unlimited duration subject to the Trust’s policy that each Trustee (other than the Trustee Emeritus) will resign at the end of the calendar year in which he or she attains age 75. Each Trustee also serves as a trustee of Wanger Advisors Trust, another open-end investment company, the series of which also are managed by the Investment Manager. The mailing address of each Trustee is: c/o Columbia Wanger Asset Management, LLC, 71 S. Wacker Drive, 25th Floor, Chicago, Illinois 60606.

Independent Trustee Biographical Information

Name, Position Held with the Trust and Age at March 31, 2022	Year First Appointed or Elected to a Board in the Columbia Funds Complex	Principal Occupation(s) During the Past Five Years	Number of Funds in the Columbia Funds Complex Overseen(1)	Other Directorships Held by Trustee During the Past Five Years
Maureen M. Culhane, 73 Trustee	2007	Retired. Formerly, Vice President, Goldman Sachs Asset Management, L.P. (investment adviser), 2005-2007; Vice President (Consultant) — Strategic Relationship Management, Goldman, Sachs & Co., 1999-2005.	9	None.
Margaret M. Eisen, 68 Trustee	2002	Trustee, Smith College 2012-2016; Chief Investment Officer, EAM International LLC (corporate finance and asset management), 2003-2013; Managing Director, CFA Institute, 2005-2008.	9	Chair, RMB Investors Trust (6 series).
John C. Heaton, 62 Trustee	2010	Joseph L. Gidwitz Professor of Finance, University of Chicago Booth School of Business since 2000; Deputy Dean for Faculty, University of Chicago Booth School of Business (2012-2019).	9	None.

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Name, Position Held with the Trust and Age at March 31, 2022	Year First Appointed or Elected to a Board in the Columbia Funds Complex	Principal Occupation(s) During the Past Five Years	Number of Funds in the Columbia Funds Complex Overseen(1)	Other Directorships Held by Trustee During the Past Five Years
Dianne F. Lob, 67, Trustee	2021	Retired. Formerly, Senior Vice President and Senior Managing Director, Global Head of Business and Product Development, AllianceBernstein Holding L.P. (asset management), 2014-2020; Chairman, Private Client Investment Policy Group, Alliance Bernstein Holding L.P., 2005-2014.	9	None.
Charles R. Phillips, 65 Trustee	2015	Retired. Formerly, Vice Chairman, J.P. Morgan Private Bank, 2011-2014; Managing Director, J.P. Morgan Private Bank, 2001-2011.	9	None.
David J. Rudis, 69 Trustee and Chair	2010	Chief Executive Officer, Finger Rock, LLC (strategic consulting business). Formerly, National Checking and Debit Executive, and Illinois President, Bank of America, 2007-2009; President, Consumer Banking Group, LaSalle National Bank, 2004-2007.	9	None.

Trustee Emeritus Biographical Information

Name, Position Held with the Trust and Age at March 31, 2022	Year First Appointed or Elected to a Board in the Columbia Funds Complex	Principal Occupation(s) During the Past Five Years	Number of Funds in the Columbia Funds Complex Overseen(1)	Other Directorships Held by Trustee During the Past Five Years
Ralph Wanger, 87, Trustee Emeritus(2)	1970(3)	Founder, CWAM. Formerly, President, Chief Investment Officer and portfolio manager, CWAM or its predecessors, July 1992-September 2003; Director, Wanger Investment Company PLC; Consultant, CWAM or its predecessors, September 2003-September 2005.	9	None.

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⁽¹⁾  The Trustees oversee the series of the Trust and the series of Wanger Advisors Trust.

⁽²⁾  As permitted under the Trust’s Bylaws, Mr. Wanger serves as a non-voting Trustee Emeritus of the Trust. Prior to September 2009, Mr. Wanger served as an “interested” trustee of the Trust and Wanger Advisors Trust. Mr. Wanger was considered an “interested person” of the Trusts and of CWAM within the meaning of the 1940 Act because of certain ownership interests.

⁽³⁾  Dates prior to April 1992 correspond to the date first elected as a director of The Acorn Fund, Inc., the Trust’s predecessor.

The Board and its Committees

Responsibilities

The Board has overall management responsibility for the Funds. The Trustees are responsible for supervising and overseeing the management and operation of the Trust. Each Trustee serves a term of unlimited duration, subject to the Trust’s policy that each Trustee (other than the Trustee Emeritus) will resign at the end of the calendar year in which he or she attains age 75 and provided that at all times a majority of Trustees has been elected by shareholders. The Trustees appoint their own successors, provided that at least two-thirds of the Trustees, after such appointment, have been elected by shareholders. Shareholders may remove a Trustee, with or without cause, upon the vote of two-thirds of the Trust’s outstanding shares at any meeting called for that purpose. A Trustee may be removed with or without cause upon the vote of a majority of the Trustees.

Leadership Structure

The Board is currently composed of six Trustees, all of whom are Independent Trustees. In addition to the six Trustees, Ralph Wanger serves as a non-voting Trustee Emeritus of the Trust. The Chair of the Board, David J. Rudis, is an Independent Trustee.

The Board met seven times during 2021.

Each trustee was nominated to serve on the Board because of his or her experience, skills and qualifications. See Trustee Experience below. The Board believes that its leadership structure is consistent with industry practices and is appropriate in light of the size of the Trust and the nature and complexity of its business. In particular:

• Board Composition. The Trustees believe that maintaining a Board composed of a super-majority of at least 75% Independent Trustees is appropriate and in the best interest of Fund shareholders. The Trustees also believe that having Mr. Wanger serve as a non-voting Trustee Emeritus (and former “interested” trustee within the meaning of the 1940 Act) brings management and financial insight that is important to certain of the Board’s decisions and also in the best interest of shareholders.

• Independent Trustee Meetings and Executive Sessions. The Trustees believe that meetings of the Independent Trustees and meetings in executive session help mitigate conflicts of interest and allow the Independent Trustees to deliberate candidly, constructively and separately from management, in a manner that affords honest disagreement and critical questioning.

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The Board has established five standing committees: the Audit & Compliance Committee; the Contract Committee; the Executive Committee; the Governance Committee; and the Investment Performance Analysis Committee. The Board has also established an Ad Hoc Committee on IT/Data Security. The Trustees believe that the number of standing and ad hoc committees, as well as the composition and scope of activities of each committee, is appropriate. The functions, responsibilities and composition of each committee are set forth below.

Committee	Members	Function	Number of Meetings in 2021
Audit & Compliance	Maureen C. Culhane (chair and audit committee financial expert) Margaret M. Eisen Dianne F. Lob David J. Rudis	Makes recommendations to the Board regarding the selection of independent auditors for the Trust; confers with the independent auditors regarding the scope and results of each audit; oversees the quality, objectivity and integrity of disclosure controls and processes and procedures employed by the Funds’ service providers in preparing the Funds’ financial statements; oversees enterprise risk management at the Investment Manager and its affiliates; provides oversight of the monitoring processes and controls regarding the Trust with respect to legal, regulatory and internal rules, policies, procedures and standards (other than those relating to audit matters); oversees compliance and risk management by the Funds’ service providers, including with respect to the Transfer Agent’s sub-transfer agent compliance program; oversees the valuation of Fund portfolio securities by the Investment Manager; identifies, reviews and addresses, with the assistance of counsel and the CCO, potential conflicts of interest between the Funds and the Investment Manager and its affiliates; monitors the performance of the CCO and makes recommendations to the Board regarding the selection and compensation of the CCO; and carries out the provisions of its charter.	5
Contract	John C. Heaton (chair) Maureen M. Culhane Margaret M. Eisen Dianne F. Lob Charles R. Phillips David J. Rudis	Makes recommendations to the Board regarding the continuation or amendment of the investment advisory agreements between the Trust and the Investment Manager and other agreements with affiliated and third party service providers; and carries out the provisions of its charter.	7

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Committee	Members	Function	Number of Meetings in 2021
Executive	David J. Rudis (chair) Alternates (Chair of the Audit & Compliance Committee; Chair of the Contract Committee; Chair of the Investment Performance Analysis Committee; Individual Trustees)	Exercises powers of the Board during intervals between meetings of the Board, with certain exceptions.	0
Governance	Charles R. Phillips (chair) John C. Heaton David J. Rudis	Makes recommendations to the Board regarding committees of the Board and committee assignments, the composition of the Board, the compensation of the Independent Trustees and candidates for election as Independent Trustees; oversees the process for evaluating the functioning of the Board; monitors the performance of counsel to the Funds and the Independent Trustees and makes recommendations to the Independent Trustees regarding the selection of their counsel; identifies, reviews and addresses, with the assistance of counsel and the Funds’ CCO, potential conflicts of interest involving the Independent Trustees; and carries out the provisions of its charter.	4
Investment Performance Analysis	Margaret M. Eisen (chair) Maureen M. Culhane John C. Heaton Dianne F. Lob Charles R. Phillips	Monitors and reviews the investment performance of each Fund; develops an appropriate framework for measuring, comparing and assessing Fund performance; provides interpretation of performance information in connection with Fund advisory contracts; acts as a liaison between the Investment Manager and the Board in overseeing and discussing investment-related issues, including portfolio management and transaction practices; oversees the Funds’ securities lending program, including by reviewing the performance of the program, the Investment Manager’s oversight of the program and GSAL’S compliance with established lending policies, and by approving vehicles for the investment of securities lending cash collateral; and carries out the provisions of its charter.	4

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Committee	Members	Function	Number of Meetings in 2021
Ad Hoc IT/Data Security	David J. Rudis (chair) Maureen M. Culhane Margaret M. Eisen John C. Heaton Dianne F. Lob Charles R. Phillips	Oversees information technology and data security matters affecting the Funds.	1

The Governance Committee’s policy with respect to considering Trustee candidates recommended by shareholders and the procedures to be followed by shareholders in submitting such recommendations are set forth in the charter. The Governance Committee has stated that the principal criterion for the selection of candidates is their ability to contribute to the overall functioning of the Board and to carry out the responsibilities of the Trustees.

The Governance Committee believes that the Board should be comprised of Trustees who represent a broad cross section of backgrounds, skills and experience, and that each Trustee should generally exhibit stature and experience commensurate with the responsibility of representing the Funds. The Governance Committee periodically reviews the membership of the Board to determine whether it may be appropriate to add individuals with backgrounds or skill sets different from those of the current Trustees. The Governance Committee follows the process it deems appropriate under the circumstances. Generally, the Governance Committee identifies Trustee candidates from references provided by the Independent Trustees and others, including nominees recommended by shareholders, and evaluates them through a process of questionnaires and multiple interviews. Through this process, the Governance Committee seeks to identify candidates who meet the particular needs of the Board at the time based on the existing make up of the Board. In addition, counsel to the Independent Trustees analyzes each Independent Trustee candidate to ensure that the candidate meets the independence requirements of the 1940 Act. The Trustees believe that the Board’s process for nominating Trustees effectively produces the best candidates with a diversity of qualities, experience, backgrounds and complementary skills, and that the composition of the Board allows the Board, as a body, to oversee the Funds in a manner that is consistent with the best interests of Fund shareholders.

Although the Investment Manager, the Trustees, or shareholders may submit suggestions for Independent Trustee candidates to the Governance Committee, neither the Governance Committee nor the Independent Trustees as a group consider those candidates on a preferential basis as opposed to other possible candidates. Any shareholder may submit the name of a candidate for consideration by the Governance Committee by submitting the recommendation to the Trust’s Secretary. The Secretary will forward any such recommendation to the chair of the Governance Committee promptly upon receipt.

Risk Oversight

The Board, working with the Funds’ CCO and the Investment Manager, has developed a detailed risk reporting methodology that includes dashboard reports relating to, among other matters, investment risk, credit risk, liquidity risk, counterparty risk, compliance risk and operational risk, including cybersecurity risk. Currently, the Investment Manager compiles and monitors relevant risk data on an ongoing basis and the Board, the Audit & Compliance Committee and the Investment Performance Analysis Committee receive and review risk reporting data on a quarterly basis or more frequently if circumstances warrant. The Board will continue to assess the most effective means of implementing this risk oversight process so that it receives the data that is most relevant to the Board in the exercise of its risk oversight role.

Working with the Funds’ independent registered accountants, the Audit & Compliance Committee ensures that the Funds’ annual audit scope includes risk-based considerations, such that the auditors consider the risks potentially impacting the audit findings as well as risks to the Funds’ financial position and operations. The Audit & Compliance Committee also considers and evaluates enterprise risk. In addition, the Investment Performance Analysis Committee provides the Board with information relevant to assessing risk oversight by monitoring and

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reviewing the Funds’ performance metrics, including measurements of risk-adjusted returns, and by regularly conferring with the Investment Manager on performance-related risks. The Investment Performance Analysis Committee also receives regular reports from GSAL regarding the risks associated with the Funds’ securities lending program, including counterparty risk and liquidity. The Governance Committee also considers risk management issues as appropriate.

The Funds’ CCO reports to the Audit & Compliance Committee and to the Board at least quarterly regarding compliance, operational and legal risk concerns. In addition to his quarterly reports, the CCO provides an annual report to the Board in accordance with the Funds’ compliance policies and procedures. The CCO regularly discusses relevant compliance, operational, investment and legal risk issues affecting the Funds during meetings with the Independent Trustees and consults with counsel. The CCO updates the Board on the application of the Funds’ compliance policies and procedures and discusses how they mitigate risk. The CCO also reports to the Board immediately regarding any problems associated with the Funds’ compliance policies and procedures that could expose (or that might have the potential to expose) the Funds to material risk.

Trustee Experience

The following is a description of the material attributes, skills and experiences that relate to the suitability of each Trustee to serve on the Board. In addition to these factors, a Trustee is required to possess certain other qualities such as integrity, intelligence, the ability to critically discuss and analyze issues presented to the Board and an understanding of a Trustee’s fiduciary obligations with respect to a registered investment company. The Board and Governance Committee believe that each of the Trustees possesses these characteristics in addition to other attributes discussed below.

Maureen M. Culhane. Ms. Culhane has financial, regulatory and investment experience through her positions as an executive with a large asset management firm, as a vice president of finance and treasurer of a Fortune 100 company, and as a principal of a pension and investment management consulting firm whose clients included, among others, Fortune 100 companies and state pension plans. Ms. Culhane has experience serving as a board member of a public operating company. She also is experienced in Board operations as well as oversight of the Investment Manager and other Fund service providers as a result of her service as an Independent Trustee for the past 15 years.

Margaret M. Eisen. Ms. Eisen has experience with financial, regulatory and investment matters as a result of her position as a managing director with responsibility for multibillion dollar portfolios of equities, both public and private, at two of the largest corporate pension funds in the United States. She also acquired such experience through her position as a managing director of the CFA Institute, which sets standards for measuring competence and integrity in the fields of portfolio management and investment analysis. Ms. Eisen has experience with board functions through her position as a director of a public operating company, her position as a director of a college board and her position as the chair of the board of another registered investment company. Ms. Eisen also is familiar with the operations of the Board and oversight of the Investment Manager and other Fund service providers through her service as an Independent Trustee for the past 20 years.

John C. Heaton. Mr. Heaton is experienced with investment matters as a result of his educational background and academic experience as a professor of finance at the University of Chicago, Booth School of Business. Mr. Heaton has particular experience analyzing investment performance as a result of his financial consulting positions with the investment committees of certain private funds. His consulting experience has focused on matters involving trading litigation, securities pricing, pension fund allocation and fund management. Mr. Heaton also has numerous academic publications in the fields of economics and finance. Mr. Heaton also is familiar with the operations of the Board and oversight of the Investment Manager and other Fund service providers through his service as an Independent Trustee for the past 12 years.

Dianne F. Lob. Ms. Lob has financial, regulatory, product development and management experience by virtue of her more than 40 years of working in the financial services and investment banking industries. During

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her career, Ms. Lob served as a senior managing director of a large asset management firm and investment banker specializing in mergers and acquisitions and debt and equity financing for companies in a variety of industries at a major global bank. She has experience with board functions through her former positions as the president and a member of the board of directors of a $30 billion mutual fund complex. She also is familiar with the functions of the Board and its oversight responsibilities with respect to the Investment Manager and other Fund service providers as a result of her service as an Independent Trustee since September 2021.

Charles R. Phillips. Mr. Phillips has investment, financial and regulatory experience through working for over 30 years in the financial services industry. He has direct investment experience, having served as vice chairman and client account manager for high net worth clients of a private bank within a large banking firm. Mr. Phillips is familiar with analyzing and evaluating financial statements of issuers and investment advisers as a result of his investment experience. He has experience with board functions through his former position as a director of a private foundation. Mr. Phillips is familiar with the operations of the Board and oversight of the Investment Manager and other Fund service providers through his service as an Independent Trustee over the past seven years.

David J. Rudis. Mr. Rudis has financial, banking, investment, and management experience through more than 30 years of working in the financial services industry. He has held various senior executive positions at regional and national banks, including serving as an executive of a Fortune 100 financial institution. Mr. Rudis has familiarity with complex financial, regulatory and banking issues. He also has extensive experience with operations management and business development in the financial services sector. Mr. Rudis also is familiar with the operations of the Board and the oversight of the Investment Manager and other Fund service providers through his service as a Trustee for the past 12 years.

Ralph Wanger. Mr. Wanger has investment, business, finance and regulatory experience through his position as founder of the Investment Manager as well as his position as former chief investment officer and portfolio manager of the firm. Mr. Wanger understands Board operations though his service on the Board for 52 years. Mr. Wanger serves as a non-voting Trustee Emeritus of the Trust.

Compensation

Trustees are compensated for their services to the Columbia Funds Complex on a complex-wide basis, as shown in the table below.

Independent Trustee Compensation for the Fiscal Year Ended December 31, 2021

Name of Trustee	Columbia Acorn Fund		Columbia Acorn International		Columbia Acorn USA		Columbia Acorn International Select		Columbia Thermostat Fund		Columbia Acorn European Fund		Aggregate Compensation from the Trust		Total Compensation from Columbia Funds Complex Paid to Independent Trustees
Laura M. Born(1)	$	63,566	$	32,473	$	4,288	$	6,362	$	25,379	$	1,856	$	133,928	$	151,200
Maureen M. Culhane	$	65,148	$	33,242	$	4,399	$	6,511	$	25,921	$	1,883	$	137,110	$	154,800
Margaret M. Eisen	$	63,590	$	32,456	$	4,289	$	6,356	$	25,383	$	1,849	$	133,926	$	151,200
John C. Heaton	$	60,555	$	30,903	$	4,079	$	6,051	$	24,197	$	1,767	$	127,557	$	144,000
Dianne F. Lob	$	11,163	$	5,527	$	739	$	1,124	$	4,936	$	480	$	23,973	$	27,050
Charles R. Phillips	$	65,045	$	33,239	$	4,386	$	6,512	$	26,031	$	1,902	$	137,121	$	154,800
David J. Rudis(2)	$	82,441	$	42,105	$	5,563	$	8,253	$	32,923	$	2,414	$	173,703	$	196,100

⁽¹⁾  Ms. Born served as a trustee of the Trust through December 31, 2021. During the fiscal year ended December 31, 2021, Ms. Born deferred $66,963 of her compensation from the Trust and $75,600 of her total compensation from the Columbia Funds Complex through the deferred compensation plan. At December 31, 2021, the value of Ms. Born’s account under the plan was $1,245,300.

⁽²⁾  During the fiscal year ended December 31, 2021, Mr. Rudis deferred all of his compensation from the Trust and all of his total compensation from the Columbia Funds Complex through the deferred compensation plan. At December 31, 2021, the value of Mr. Rudis’s account under the plan was $3,749,713.

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Trustee Emeritus Compensation for the Fiscal Year Ended December 31, 2021

Name of Trustee	Columbia Acorn Fund		Columbia Acorn International		Columbia Acorn USA		Columbia Acorn International Select		Columbia Thermostat Fund		Columbia Acorn European Fund		Aggregate Compensation from the Trust		Total Compensation from Columbia Funds Complex Paid to Trustees
Ralph Wanger(1)	$	31,501	$	16,088	$	2,120	$	3,153	$	12,407	$	907	$	66,181	$	74,700

⁽¹⁾  During the fiscal year ended December 31, 2021, Mr. Wanger deferred all of his compensation from the Trust and all of his total compensation from the Columbia Funds Complex through the deferred compensation plan. At December 31, 2021, the value of Mr. Wanger’s account under the plan was $3,052,253.

The officers and Trustees affiliated with the Investment Manager serve without any compensation from the Trust. The Trust and Wanger Advisors Trust have adopted a deferred compensation plan for the Independent Trustees and Mr. Wanger. Under the plan, any Trustee who is not an “interested person” of the Trust or the Investment Manager (participating Trustees) and Mr. Wanger may defer receipt of all or a portion of their compensation as Trustees in order to defer payment of income taxes or for other reasons. The deferred compensation payable to a participating Trustee is credited to a book reserve account as of the business day such compensation would have been paid to such Trustee. The value of a participant’s deferral account at any time is equal to the value that the account would have had if the contributions to the account had been invested in Class Inst 3 shares (as of January 1, 2022, and Class Inst shares prior thereto, with legacy Class Inst shares converted to Class Inst 3 shares effective April 1, 2022) of one or more of the Funds or in shares of Columbia Government Money Market Fund — or, prior to May 1, 2010, other affiliated money market funds — as designated by the participant. Upon retirement, the Trustee may receive payments under the plan in a lump sum or in equal annual installments over a period of five years depending on his or her election in accordance with the terms of the plan. If a participating Trustee dies, any amount payable under the plan will be paid to that Trustee’s designated beneficiaries. Each Fund’s obligation to make payments under the plan is a general obligation of that Fund. No Fund is liable for any other Fund’s obligations to make payments under the plan.

The Agreement and Declaration of Trust (the Declaration of Trust) provides that the Trust will indemnify its Trustees and officers against liabilities and expenses incurred in connection with litigation in which they may be involved because of their offices with the Trust but that such indemnification will not relieve any officer or Trustee of any liability to the Trust or its shareholders by reason of willful misfeasance, bad faith, gross negligence or reckless disregard of his or her duties. The Trust, at its expense, provides liability insurance for the benefit of its Trustees and officers.

Beneficial Equity Ownership

The table below shows, for each Trustee, the amount of equity securities of each Fund beneficially owned by the Trustee and the aggregate value of all investments in equity securities of the Columbia Funds Complex, including notional amounts through the deferred compensation plan, stated as one of the following ranges: A = $0; B = $1—$10,000; C = $10,001—$50,000; D = $50,001—$100,000; and E = over $100,000.

Certain of the Trustees and officers of the Funds individually and in the aggregate beneficially own more than 1% of the outstanding Class Inst shares of certain Funds. For details, see Control Persons and Principal Shareholders — Management Ownership of the Funds.

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Independent Trustee Ownership for the Calendar Year Ended December 31, 2021

Name of Trustee	Columbia Acorn Fund	Columbia Acorn International	Columbia Acorn USA	Columbia Acorn International Select	Columbia Acorn European Fund	Columbia Thermostat Fund	Aggregate Dollar Range of Equity Securities in all Funds in the Columbia Funds Complex
Maureen M. Culhane	A	A	A	E	D	A	E
Margaret M. Eisen	A	E	A	A	A	A	E
John C. Heaton	E	A	A	A	A	A	E
Dianne F. Lob	C	C	A	A	A	A	D
Charles R. Phillips	A	D	A	A	A	A	D
David J. Rudis	E	A	A	C	A	E	E

Trustee Emeritus Ownership for the Calendar Year Ended December 31, 2021

Name of Trustee	Columbia Acorn Fund	Columbia Acorn International	Columbia Acorn USA	Columbia Acorn International Select	Columbia Acorn European Fund	Columbia Thermostat Fund	Aggregate Dollar Range of Equity Securities in all Funds in the Columbia Funds Complex
Ralph Wanger	E	E	E	E	A	E	E

The Officers

The following table provides basic information about the officers of the Trust, including their principal occupations during the past five years, although their specific titles may have varied over the period. The mailing address of each officer is: c/o Columbia Wanger Asset Management, LLC, 71 S. Wacker Drive, 25th Floor, Chicago, Illinois 60606, except for (i) Mses. Pilat and Skinner and Messrs. Beckman, Clarke, Larrenaga, McGuire and Quero, whose address is c/o Columbia Management Investment Advisers, LLC, 290 Congress Street, Boston, MA 02210 and (ii) Mr. Beranek, whose address is c/o Columbia Management Investment Advisers, LLC, 5890 Ameriprise Financial Center, Minneapolis, MN 55474.

Officer Biographical Information

Name and Age at March 31, 2022	Position with the Trust*	Year First Appointed or Elected to Office	Principal Occupation(s) During the Past Five Years
Dan Beckman, 60	Co-President and Principal Executive Officer	2021	Vice President – Head of North America Product, Columbia Management Investment Advisers, LLC since April 2015; Trustee, President and Principal Executive Officer of the Columbia Funds since June 2021; officer of Columbia Funds and affiliated funds since 2020-2021; Board of Governors, CWAM since January 2022; Director, Ameriprise Trust Company, since October 2016; Director, Columbia Management Investment Distributors, Inc. since November 2018.

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Name and Age at March 31, 2022	Position with the Trust*	Year First Appointed or Elected to Office	Principal Occupation(s) During the Past Five Years
Joseph Beranek, 57	Assistant Treasurer	2022	Vice President – Mutual Fund Accounting and Financial Reporting, Columbia Management, since December 2018 and March 2017, respectively (previously Vice President – Pricing and Corporate Actions, May 2010-March 2017); Treasurer and Chief Accounting Officer of Columbia Funds since 2019.
James Chapman, 52	Vice President	2021	Portfolio manager and/or analyst, CWAM since 2018; partner, TDKY Advisors, September 2017-July 2018; portfolio manager and analyst, GMO LLC, November 2009-June 2017.
Michael G. Clarke, 52	Treasurer and Principal Accounting and Financial Officer	2004	Senior Vice President – Head of Global Operations since February 2022, Vice President – Co-Head of Global Operations from June 2019 to January 2022, Vice President – Mutual Fund Accounting & Administration Services, Columbia Management from May 2010 to May 2019; Assistant Treasurer, Columbia Acorn Trust and Wanger Advisors Trust from 2004 to 2021; senior officer of Columbia Funds and affiliated funds since 2002.
Daniel Cole, 57	Vice President	2022	Senior Portfolio Manager of Columbia Management since 2014; Vice President of CWAM since April 2021.
John L. Emerson, 47	Vice President	2020	Portfolio manager and/or analyst, CWAM since 2003.
Tae Han (Simon) Kim, 42	Vice President	2018	Director of International Research, CWAM, since 2020; portfolio manager and/or analyst, CWAM since 2011.
Stephen Kusmierczak, 55	Co-President	2011	International Team Head, CWAM, since 2020; portfolio manager and/or analyst, CWAM or its predecessors since 2001;

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Name and Age at March 31, 2022	Position with the Trust*	Year First Appointed or Elected to Office	Principal Occupation(s) During the Past Five Years
			President, Columbia Acorn Trust and Wanger Advisors Trust, April 2021-July 2022 and Co-President, Columbia Acorn Trust and Wanger Advisors Trust, September 2020-April 2021; Vice President, Columbia Acorn Trust and Wanger Advisors Trust, 2011-2020.
Joseph C. LaPalm, 52	Vice President	2006	Chief Compliance Officer, CWAM since 2005.
Ryan C. Larrenaga, 51	Assistant Secretary and Chief Legal Officer	2015	Vice President and Chief Counsel, Ameriprise Financial since August 2018 (previously, Vice President and Group Counsel, August 2011-August 2018); Senior Vice President and Chief Legal Officer since 2017, and Secretary since 2015, Columbia Funds; officer of Columbia Funds and affiliated funds since 2005.
Erika K. Maschmeyer, 41	Vice President	2020	Director of Research (U.S.), CWAM, since April 2021; portfolio manager and/or analyst, CWAM since 2016.
Thomas P. McGuire, 49	Chief Compliance Officer	2015	Senior Vice President and Chief Compliance Officer of the Columbia Funds since 2012; Vice President – Asset Management Compliance, Ameriprise Financial since May 2010; Chief Compliance Officer, Ameriprise Certificate Company, September 2010-September 2020.
Sebastien Pigeon, 50	Vice President	2021	Portfolio manager and/or analyst, CWAM since 2015.
Marybeth Pilat, 53	Assistant Treasurer	2022	Vice President – Product Pricing and Administration, Columbia Management, since May 2017; Director-Fund Administration, Calvert Investments, August 2015-March 2017.
Julian Quero, 55	Assistant Treasurer	2015	Vice President-Tax, Columbia Management since 2009.

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Name and Age at March 31, 2022	Position with the Trust*	Year First Appointed or Elected to Office	Principal Occupation(s) During the Past Five Years
Martha A. Skinner, 47	Assistant Treasurer	2016	Vice President of Financial Reporting and Administration, Columbia Management since November 2015.
Hans F. Stege, 37	Vice President	2020	Portfolio manager and/or analyst, CWAM since 2017; prior thereto, portfolio manager and analyst, Copia Capital.
Zoe Tan, 37	Vice President	2021	Portfolio manager and/or analyst, CWAM since 2018; senior analyst, Driehaus Capital Management, January 2014-June 2017.
Linda Roth-Wiszowaty, 52	Secretary	2006	Business support analyst, CWAM since April 2007; Assistant Secretary, Columbia Acorn Trust and Wanger Advisors Trust, 2011-2020.

* The Trust’s officers also serve in the indicated roles for Wanger Advisors Trust.

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BROKERAGE ALLOCATION AND OTHER PRACTICES

Subject to policies established by the Board, as well as the terms of the Advisory Agreement, the Investment Manager is responsible for decisions to buy and sell securities and other instruments and assets for a Fund, for the selection of broker-dealers, for the execution of a Fund’s transactions and for the allocation of brokerage commissions in connection with such transactions. The Investment Manager effects transactions for the Fund consistent with its duty to seek best execution of client (including Fund) orders under the circumstances of the particular transaction. Purchases and sales of securities on a securities exchange are effected through broker-dealers who charge negotiated commissions for their services. Orders may be directed to any broker-dealer to the extent and in the manner permitted by applicable law and by the policies and procedures of the Investment Manager.

In the over-the-counter market, securities generally are traded on a “net” basis with dealers acting as principals for their own accounts without stated commissions, although the price of a security usually includes a profit to the dealer. In underwritten offerings, securities are bought at a fixed price that includes an amount of compensation to the underwriter, generally referred to as the underwriter’s “concession” or “discount.” On occasion, certain money market instruments may be bought directly from an issuer, in which case no commissions or discounts are paid.

The Investment Manager effects security transactions for the Funds consistent with its duty to seek best execution of client (including the Funds) orders under the circumstances of the particular transaction, which may result in a Fund paying a brokerage commission in excess of what another broker-dealer might have charged for effecting the same transaction. In seeking such execution, the Investment Manager will use its best judgment in evaluating the terms of a transaction, and will give consideration to various relevant factors, including, without limitation, the size and type of the transaction, the nature and character of the market for the security or other instrument or asset, the confidentiality, speed and certainty of effective execution required for the transaction, the general execution and operational capabilities of the broker-dealer, the reputation, reliability, experience and financial condition of the broker-dealer, the value and quality of the services rendered by the broker-dealer in this instance and other transactions and the reasonableness of the spread or commission, if any. Reports on brokerage commissions are provided at least annually to the Board.

Research services received from broker-dealers supplement the Investment Manager’s own research and may include the following types of information: statistical and background information on industry groups and individual companies; forecasts and interpretations with respect to U.S. and foreign economies, securities, markets, specific industry groups and individual companies; information on political developments; Fund management strategies; performance information on securities and other instruments and assets and information concerning prices of same; and information supplied by specialized services to the Investment Manager and to the Board with respect to the performance, investment activities and fees and expenses of other funds. Such information may be communicated electronically, orally or in written form.

Broker-dealers may, from time to time, arrange meetings with management of companies and provide access to consultants who supply research information. The outside research is useful to the Investment Manager since, in certain instances, the broker- dealers utilized by the Investment Manager may follow a different universe of issuers and other matters than those that the Investment Manager’s staff follow. In addition, this research provides the Investment Manager with a different perspective on investment matters, even if the securities research obtained relates to issuers followed by the Investment Manager.

Research services that are provided to the Investment Manager by broker-dealers are available for the benefit of all accounts managed or advised by the Investment Manager. In some cases, the research services are available only from the broker-dealer providing such services. In other cases, the research services may be obtainable from alternative sources. Broker-dealer research typically supplements rather than replaces the Investment Manager’s own research, tending to improve the quality of its investment advice. However, to the

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extent that the Investment Manager would have bought any such research services had such services not been provided by broker-dealers, the expenses of such services to the Investment Manager could be considered to have been reduced accordingly. Certain research services furnished by broker-dealers may be useful to the clients of the Investment Manager other than the Fund or Funds whose trading through a broker-dealer generated the research services. Conversely, any research services received by the Investment Manager through the placement of transactions of other clients may be of value to the Investment Manager in fulfilling its obligations to the Funds.

The Investment Manager is of the opinion that this material is beneficial in supplementing its research and analysis; and, therefore, it may benefit the Funds by improving the quality of the Investment Manager’s investment advice. The advisory fees paid by the Funds are not reduced because the Investment Manager receives such services.

Unless prohibited by applicable law, Section 28(e) of the 1934 Act, provides a “safe harbor” for the Investment Manager to obtain research used in investment decision-making and brokerage services with client commissions. As a result, broker-dealers typically provide services including research and execution of transactions. The research provided can be either broker-dealer proprietary research (created and provided by a broker-dealer, including tangible research products as well as access to analysts and traders) or third party research (created by a third party but provided by a broker-dealer). The Investment Manager uses broker-dealers who provide both types of research products and services, as well as brokerage products and services, in exchange for commissions generated by transactions in the client accounts (including the Funds), also known as “soft dollars” or client commission arrangements.

Under Section 28(e) of the 1934 Act, the Investment Manager shall not be “deemed to have acted unlawfully or to have breached its fiduciary duty” solely because under certain circumstances it has caused the account to pay a higher commission than the lowest available. To obtain the benefit of Section 28(e), the Investment Manager must make a good faith determination that the commissions paid are “reasonable in relation to the value of the brokerage and research services provided by such member, broker, or dealer, viewed in terms of either that particular transaction or his overall responsibilities with respect to the accounts as to which he exercises investment discretion.” Accordingly, the price to a Fund in any transaction may be less favorable than that available from another broker-dealer if the difference is reasonably justified by other aspects of the brokerage and research services offered. Generally, the Investment Manager may execute trades through a broker-dealer, which subsequently makes payment to a research-producing broker-dealer at the Investment Manager’s direction, retaining a predetermined portion of the commissions for execution. The Investment Manager determines the amount of the payments through a broker research evaluation process. This compensation method, sometimes referred to as a “commission sharing arrangement” allows the Investment Manager to more selectively obtain research from one broker-dealer while seeking the execution services of another, preferred execution broker-dealer. Such commission sharing arrangements do not obligate the Investment Manager to generate a specified level of commissions with the executing broker-dealers. The Board reviews the Investment Manager’s soft dollar practices at least annually.

The Investment Manager does not consider sales of shares of the Funds as a factor in the selection of broker-dealers through which to execute securities transactions on behalf of the Funds. On a periodic basis, the Investment Manager makes a comprehensive review of the broker-dealers and the overall reasonableness of their commissions, and evaluates execution, operational efficiency, and research services. Certain limited reviews are also conducted by an independent third-party evaluator.

Commission rates are established pursuant to negotiations with broker-dealers based on the quality and quantity of execution services provided by broker-dealers in light of generally prevailing rates. On exchanges on which commissions are negotiated, the cost of transactions may vary among different broker-dealers. Transactions on foreign stock exchanges involve payment of brokerage commissions that generally are fixed. Transactions in both foreign and domestic over-the-counter markets generally are principal transactions with

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dealers, and the costs of such transactions involve dealer spreads rather than brokerage commissions. With respect to over-the-counter transactions, the Investment Manager, where possible, will deal directly with dealers who make a market in the securities involved, except in those circumstances in which better prices and execution are available elsewhere.

Some broker-dealers may indicate that the provision of research products is dependent upon the generation of certain specified levels of commission by the Funds. The Investment Manager’s research analysts periodically rate the quality of research products provided by various broker-dealer firms. Based on these evaluations, the Investment Manager develops target levels of commission dollars on a firm-by-firm basis. The Investment Manager attempts to direct trades to each individual approved broker-dealer firm to meet those targets. The targets that the Investment Manager establishes for various broker-dealers for both proprietary and for third party research typically reflect discussions that the Investment Manager has with the broker-dealer providing the research regarding the level of commissions it expects to receive for the research. However, those targets, which are established on a calendar year basis, are not binding commitments, and the Investment Manager does not agree to direct a minimum amount of commissions to any broker-dealer for soft dollar research. In setting those targets, the Investment Manager makes a determination that the value of the research is reasonably commensurate with the cost of acquiring it. The Investment Manager will receive the research whether or not commissions directed to the applicable broker-dealer are less than, equal to or in excess of the target. The Investment Manager generally will carry over target shortages and excesses to the next year’s target. The Investment Manager believes that this practice reduces the conflicts of interest associated with soft dollar transactions, since the Investment Manager can meet the non-binding expectations of broker-dealers providing soft dollar research over flexible time periods. In the case of third party research, the third party is paid by the broker-dealer and not by the Investment Manager.

In certain instances, the Investment Manager pays for research products with commissions on trades executed through electronic communications networks (ECNs). The Investment Manager may direct a portion of the commissions from these trades to an introducing broker through a Commission Sharing Agreement (CSA). Where the Investment Manager has executed a CSA with an introducing broker-dealer, the Investment Manager will place a trade with the ECN, and pay the negotiated commission to the ECN. The ECN will then credit a negotiated portion of the commission to the introducing broker-dealer as requested by the Investment Manager for the purpose of funding a pool to be used to pay for research products or services received by the Investment Manager from other third parties. In addition, the ECN will credit a further portion of the commission negotiated by the ECN and the introducing broker-dealer to the introducing broker-dealer for its services in administrating the CSA. The ECN makes periodic lumpsum payments to the introducing broker-dealer. CSAs are a permitted form of soft dollar transaction under Section 28(e) of the 1934 Act.

The Investment Manager may use step-out transactions. A “step-out” is an arrangement in which the Investment Manager executes a trade through one broker-dealer but instructs that broker-dealer to step-out all or a part of the trade to another broker-dealer. The second broker-dealer will clear and settle, and receive commissions for, the stepped-out portion. The Investment Manager may receive research products and services in connection with step- out transactions.

Use of Fund commissions to obtain research products and services may create potential conflicts of interest between the Investment Manager and a Fund because it allows the Investment Manager to use the research in managing its client accounts without paying cash (“hard dollars”) out of its own assets without a commensurately reduction in its advisory fees. However, the Investment Manager has policies and procedures designed to mitigate these conflicts and ensure that the use of Fund commissions falls within the “safe harbor” of Section 28(e) of the 1934 Act.

Some products and services may be used for both investment decision-making and non-investment decision-making purposes (“mixed use” items). While the Investment Manager currently does not obtain mixed use products using soft dollars, it has procedures in place to assure that Fund commissions pay only for the investment decision-making portion of a mixed-use item.

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In certain instances, there may be securities that are suitable for a Fund as well as for one or more of the other clients of the Investment Manager. Investment decisions for the Funds and for the Investment Manager’s other clients are made with the goal of achieving their respective investment objectives. A particular security may be bought or sold for only one client even though it may be held by, or bought or sold for, other clients. Likewise, a particular security may be bought for one or more clients when one or more other clients are selling that same security. Some simultaneous transactions are inevitable when a number of accounts receive investment advice from the same investment adviser, particularly when the same security is suitable for the investment objectives of more than one client. When two or more clients are engaged simultaneously in the purchase or sale of the same security, the securities are allocated among clients in a manner believed to be equitable to each. In some cases, this policy could have a detrimental effect on the price or volume of the security in a particular transaction that may affect the Funds.

Columbia Threadneedle operates several trading desks in different geographic locations that support different portfolio management teams managing a variety of accounts and products, including the Investment Manager’s portfolio management teams supporting the Funds. The Columbia Threadneedle trading desks are functionally and operationally integrated to operate as one virtual desk. While the trading desks operate in several locations, the desks operate under the same oversight and reporting lines and are generally conducted under similar policies and procedures.

As the Investment Manager seeks to enhance its investment capabilities and services to its clients, including the Funds, the Investment Manager may engage certain of its investment advisory affiliates (Participating Affiliates) around the world to provide a variety of services. For example, the Investment Manager may engage Participating Affiliates and their personnel to provide (jointly or in coordination with the Investment Manager) services relating to client relations, investment monitoring, account administration and trading for certain accounts the Investment Manager manages, including the Funds, other pooled vehicles and separately managed accounts. In some circumstances, a Participating Affiliate may delegate responsibility for providing those services to another Participating Affiliate. In addition, the Investment Manager may provide certain similar services to its Participating Affiliates for accounts they manage.

The Investment Manager believes that harnessing the collective expertise of the firm and its Participating Affiliates will benefit its clients through the use of expanded and shared capabilities, including the sharing of research and other information by investment personnel (e.g., portfolio managers and analysts) relating to economic perspectives, market analysis and equity securities analysis.

Participating Affiliates may provide certain trading-related services to the Investment Manager’s accounts, including the Funds. The Investment Manager may also provide similar services to certain accounts of Participating Affiliates. The Investment Manager believes that local trading in certain local markets will benefit its clients, including the Funds. However, such services may result in potential conflicts of interest to such accounts.

The Funds may participate, if and when practicable, in bidding for the purchase of portfolio securities directly from an issuer in order to take advantage of the lower purchase price available to members of a bidding group. A Fund will engage in this practice, however, only when the Investment Manager, in its sole discretion, believes such practice to be otherwise in such Fund’s interests.

The Funds will not execute portfolio transactions through, or buy or sell portfolio securities from or to the Investment Manager and its affiliates acting as principal (including repurchase and reverse repurchase agreements), except to the extent permitted by applicable law, regulation or order. However, the Investment Manager is authorized to allocate buy and sell orders for portfolio securities to certain broker-dealers and financial institutions, including, in the case of agency transactions, broker-dealers and financial institutions that are affiliated with Ameriprise Financial. To the extent that a Fund executes any securities trades with an affiliate of Ameriprise Financial, such Fund does so in conformity with Rule 17e-1 under the 1940 Act and the

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procedures that such Fund has adopted pursuant to the rule. In this regard, for each transaction, the Board will determine that the transaction is effected in accordance with the Funds’ Rule 17e-1 procedures, which require: (i) the transaction resulted in prices for and execution of securities transactions at least as favorable to the particular Fund as those likely to be derived from a non-affiliated qualified broker-dealer; (ii) the affiliated broker-dealer charged the Fund commission rates consistent with those charged by the affiliated broker-dealer in similar transactions to clients comparable to the Fund and that are not affiliated with the broker-dealer in question; and (iii) the fees, commissions or other remuneration paid by the Fund did not exceed 2% of the sales price of the securities if the sale was effected in connection with a secondary distribution, or 1% of the purchase or sale price of such securities if effected in other than a secondary distribution.

Certain affiliates of Ameriprise Financial may have deposit, loan or commercial banking relationships with the corporate users of facilities financed by industrial development revenue bonds or private activity bonds bought by certain of the Funds.

Ameriprise Financial or certain of its affiliates may serve as trustee, custodian, tender agent, guarantor, placement agent, underwriter, or in some other capacity, with respect to certain issues of securities. Under certain circumstances, a Fund may buy securities from a member of an underwriting syndicate in which an affiliate of Ameriprise Financial is a member. The Funds have adopted procedures pursuant to Rule 10f-3 under the 1940 Act, and intend to comply with the requirements of Rule 10f-3, in connection with any purchases of securities that may be subject to Rule 10f-3.

Given the breadth of the Investment Manager’s investment management activities, investment decisions for the Funds are not always made independently from those other investment companies and accounts advised or managed by the Investment Manager. To the extent permitted by law, when a purchase or sale of the same security is made at substantially the same time on behalf of one or more of the Funds and another investment portfolio, investment company or account, the Investment Manager may aggregate the securities to be sold or bought for the Funds with those to be sold or bought for other investment portfolios, investment companies or accounts in executing transactions, and such transactions will be averaged as to price and available investments allocated as to amount in a manner which the Investment Manager believes to be equitable to the Funds and such other investment portfolio, investment company or account. In some instances, this investment procedure may adversely affect the price paid or received by a Fund or the size of the position obtained or sold by the Fund.

See Investment Management and Other Services – Other Roles and Relationships of Ameriprise Financial and its Affiliates –Certain Conflicts of Interest for more information about these and other conflicts of interest.

Brokerage Commissions

The following table describes the amounts of brokerage commissions paid by the Funds during their three most recently completed fiscal years. In certain instances the Funds may pay brokerage commissions to broker-dealers that are affiliates of Ameriprise Financial. As indicated above, all such transactions involving the payment of brokerage commissions to affiliates are done in compliance with Rule 17e-1 under the 1940 Act.

Aggregate Brokerage Commissions Paid by the Funds

Fund	Fiscal Year Ended December 31, 2021		Fiscal Year Ended December 31, 2020		Fiscal Year Ended December 31, 2019
Columbia Acorn Fund	$	2,730,299	$	3,156,000	$	3,830,000
Columbia Acorn International	$	2,084,948	$	3,787,000	$	2,487,000
Columbia Acorn USA	$	233,179	$	379,000	$	412,000
Columbia Acorn International Select	$	400,337	$	494,000	$	139,000
Columbia Acorn European Fund	$	164,770	$	81,000	$	59,000
Columbia Thermostat Fund	$	33,185	$	38,000	$	15,000

The Funds paid no brokerage commissions to affiliated broker-dealers for the fiscal years ended December 31, 2021, December 31, 2020 and December 31, 2019.

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Directed Brokerage

The Funds or the Investment Manager, through an agreement or understanding with a broker-dealer, or otherwise through an internal allocation procedure, may direct, subject to applicable legal requirements, the Funds’ brokerage transactions to a broker-dealer because of the research services it provides the Funds or the Investment Manager.

During the fiscal year ended December 31, 2021, the Funds directed brokerage transactions in the dollar amounts shown in the following table, which also shows the commissions paid to broker-dealers in connection with those transactions.

	Directed Commissions		Directed Transactions
Columbia Acorn Fund	$	2,267,414	$	6,554,899,319
Columbia Acorn International	$	1,682,058	$	1,332,917,128
Columbia Acorn USA	$	192,933	$	419,434,822
Columbia Acorn International Select	$	317,280	$	242,073,317
Columbia Acorn European Fund	$	131,703	$	103,463,405
Columbia Thermostat Fund		—		—

Securities of Regular Broker-Dealers

In certain cases, the Funds, as part of their principal investment strategies, or otherwise as a permissible investment, will invest in the common stock or debt obligations of the regular broker-dealers that the Investment Manager uses to transact brokerage for the Columbia Funds Complex.

As of December 31, 2021, the Funds did not own securities of any “regular broker or dealers” or their parents, as defined in Rule 10b-1 under the 1940 Act.

Additional Shareholder Servicing Payments

The Funds, along with the Transfer Agent, the Distributor and the Investment Manager may pay significant amounts to Financial Intermediaries, including other Ameriprise Financial affiliates, for providing the types of services that would otherwise be provided directly by a mutual fund’s transfer agent. The level of payments made to Financial Intermediaries may vary by Financial Intermediary and according to distribution channel. A number of factors may be considered in determining payments to a Financial Intermediary, including, without limitation, the nature of the services provided to shareholders or retirement plan participants that invest in the Funds through retirement plans. These services may include sub-accounting, sub-transfer agency, participant recordkeeping, shareholder or participant reporting, shareholder or participant transaction processing, shareholder or participant tax monitoring and reporting and/or the provision of call center support and other customer services (Additional Shareholder Services).

Payments for Additional Shareholder Services vary by Financial Intermediary. Subject to certain limitations, the Board has authorized the Funds to compensate the Transfer Agent for payments made to such Financial Intermediaries, including Ameriprise Financial affiliates, for Additional Shareholder Services in amounts that vary with the type of intermediary and the type of Additional Shareholder Services provided. The Funds believe that such compensation levels are reasonably related to the Additional Shareholder Services provided, but payments may vary due to competitive pressure and there can be no assurance that a Fund will be able to identify with specificity the costs of particular Additional Shareholder Services for which compensation is paid. The amounts payable to such Financial Intermediaries for Additional Shareholder Services in excess of the amounts paid by the Fund are borne by the Distributor or other Ameriprise Financial affiliates from their own resources. These payments are in addition to the annual transfer agency fees paid by a Fund to the Transfer Agent, as described in Investment Management and Other Services — Other Services Provided — The Transfer Agent, and may include payments to financial intermediaries that charge networking fees for certain services provided in connection with the maintenance of shareholder accounts through the NSCC.

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In addition, the Distributor and other Ameriprise Financial affiliates may make lump sum payments to selected Financial Intermediaries receiving shareholder servicing payments as compensation for the costs of printing literature for participants, account maintenance fees or fees for establishment of the Funds on the Financial Intermediary’s system or other similar services.

As of April 2022, the Transfer Agent and/or other Ameriprise Financial affiliates had agreed to make shareholder servicing payments with respect to the Funds to the Financial Intermediaries or their affiliates shown below.

Recipients of Shareholder Servicing Payments relating to the Funds from the Transfer Agent and/or other Ameriprise Financial affiliates

•  ADP Broker-Dealer, Inc. •  American United Life Insurance Co. •  American Enterprise Investment Services Inc.* •  Ameriprise Financial Services, LLC* •  Ascensus, Inc. •  Avantax Investment Services, Inc. •  AXA Equitable Life Insurance •  Bank of America, N.A. •  Benefit Plan Administrators •  Benefit Trust •  BMO Harris Bank •  BNY Mellon, N.A. •  Charles Schwab & Co., Inc. •  Charles Schwab Trust Co. •  City National Bank •  Digital Retirement Solutions •  Edward D. Jones & Co., LP •  Fidelity Brokerage Services Inc. •  Fidelity Investments Institutional Operations Co. •  Genworth Life and Annuity Insurance Company •  Genworth Life Insurance Co. of New York •  Goldman Sachs & Co. •  GWFS Equities, Inc. •  Hartford Life Insurance Company •  Janney Montgomery Scott, Inc. •  John Hancock Life Insurance Company (USA) •  John Hancock Life Insurance Company of New York •  John Hancock Trust Company •  JPMorgan Securities LLC •  Lincoln Life & Annuity Company of New York •  Lincoln National Life Insurance Company •  Lincoln Retirement Services •  LPL Financial Corporation •  Massachusetts Mutual Life Insurance Company •  Merrill Lynch, Pierce, Fenner & Smith Incorporated •  Mid Atlantic Capital Corporation •  Minnesota Life Insurance Co. •  Morgan Stanley Smith Barney •  MSCS Financial Services Division of Broadridge Business Process Outsourcing LLC •  National Financial Services •  Nationwide Investment Services •  Newport Retirement Services, Inc. •  Oppenheimer & Co., Inc. •  Pershing LLC •  Plan Administrators, Inc. •  PNC Bank •  Principal Life Insurance Company of America •  Prudential Insurance Company of America •  Prudential Retirement Insurance & Annuity Company •  Raymond James & Associates •  Reliance Trust •  Sammons Retirement Solutions •  SEI Private Trust Company •  Standard Insurance Company •  Stifel Nicolaus & Co. •  TD Ameritrade Clearing, Inc. •  TD Ameritrade Trust Company •  Teachers Insurance and Annuity Association of America •  Transamerica Advisors Life Insurance Company •  Transamerica Advisors Life Insurance Company of New York •  Transamerica Financial Life Insurance Company •  T. Rowe Price Group, Inc. •  UBS Financial Services, Inc. •  Unified Trust Company, N.A. •  US Bank N.A. •  VALIC Retirement Services Company •  Vanguard Group, Inc. •  Voya Retirement Insurance and Annuity Company •  Wells Fargo Advisors •  Wells Fargo Bank, N.A. •  Wells Fargo Clearing Services LLC

* An affiliate of Ameriprise Financial.

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The Transfer Agent and/or other Ameriprise Financial affiliates may enter into similar arrangements with other Financial Intermediaries from time to time. Therefore, the preceding list is subject to change at any time without notice.

Additional Financial Intermediary Payments

Financial Intermediaries may receive different commissions, sales charge reallowances and other payments with respect to sales of different classes of shares of the Funds. These other payments may include servicing payments to retirement plan administrators and other institutions at rates up to those described above under Brokerage Allocation and Other Practices — Additional Shareholder Servicing Payments.

The Distributor and other Ameriprise Financial affiliates may pay additional compensation to selected Financial Intermediaries, including other Ameriprise Financial affiliates, under the categories described below. These categories are not mutually exclusive, and a single Financial Intermediary may receive payments under all categories. A Financial Intermediary also may receive payments described above in Brokerage Allocation and Other Practices — Additional Shareholder Servicing Payments. These payments may create an incentive for a Financial Intermediary or its representatives to recommend or offer shares of a Fund to its customers. The amount of payments made to Financial Intermediaries may vary. In determining the amount of payments to be made, the Distributor and other Ameriprise Financial affiliates may consider a number of factors, including, without limitation, asset mix and length or relationship with the Financial Intermediary, the size of the customer/shareholder base of the Financial Intermediary, the manner in which customers of the Financial Intermediary make investments in the Funds, the nature and scope of marketing support or services provided by the Financial Intermediary (as described more fully below) and the costs incurred by the Financial Intermediary in connection with maintaining the infrastructure necessary or desirable to support investments in the Funds.

These additional payments by the Distributor and other Ameriprise Financial affiliates are made pursuant to agreements between the Distributor and other Ameriprise Financial affiliates and Financial Intermediaries, and do not change the price paid by investors for the purchase of a share, the amount a Fund will receive as proceeds from such sales or the distribution fees and expenses paid by the Fund as shown under the heading Fees and Expenses in the Fund’s prospectus.

Marketing Support Payments

The Distributor and its affiliates make payments, from their own resources, to certain Financial Intermediaries, including other Ameriprise Financial affiliates, for marketing support services relating to the Columbia Funds, including, but not limited to, business planning assistance, educating Financial Intermediary personnel about the Funds and shareholder financial planning needs, placement on the Financial Intermediary’s preferred or recommended fund list or otherwise identifying the Funds as being part of a complex to be accorded a higher degree of marketing support than complexes not making such payments, access to sales meetings, sales representatives and management representatives of the Financial Intermediary, client servicing, systems infrastructure support and data analytics. Not all financial intermediaries receive Marketing Support Payments. These payments are generally based upon one or more of the following factors: average net assets of the Columbia Funds distributed by the Distributor attributable to that Financial Intermediary, gross sales of the Columbia Funds distributed by the Distributor attributable to that Financial Intermediary, reimbursement of ticket charges (fees that a Financial Intermediary charges its representatives for effecting transactions in Fund shares) or a negotiated lump sum payment.

While the financial arrangements may vary for each Financial Intermediary, the marketing support payments to each Financial Intermediary generally are expected to be between 0.01% and 0.40% on an annual basis for payments based on average net assets of the Funds attributable to the Financial Intermediary, and between 0.05% and 0.25% on an annual basis for firms receiving a payment based on gross sales of the Columbia Funds attributable to the Financial Intermediary. The Distributor, the Investment Manager and other Ameriprise Financial affiliates make payments with respect to a Fund or the Columbia Funds in materially larger amounts or on a basis materially different from those described above when dealing with certain Financial Intermediaries.

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As of April 2022, the Distributor, the Investment Manager or their affiliates had agreed to make marketing support payments relating to the Funds to the Financial Intermediaries or their affiliates shown below.

Recipients of Marketing Support Payments relating to the Funds from the Distributor and/or other Ameriprise Financial affiliates
•  AIG Advisor Group •  American Enterprise Investment Services, LLC* •  Cetera Financial Group •  Citigroup Global Markets Inc./Citibank •  Commonwealth Financial Network •  Lincoln Financial Advisors Corp. •  LPL Financial Corporation •  Merrill Lynch, Pierce, Fenner & Smith Incorporated •  Morgan Stanley Smith Barney	•  Northwestern Mutual Investment Services, LLC •  PNC Investments •  Raymond James & Associates, Inc. •  Raymond James Financial Services, Inc. •  UBS Financial Services Inc. •  Unified Trust Company, N.A. •  US Bancorp Investments, Inc. •  Vanguard Marketing Corp. •  Wells Fargo Advisors, LLC •  Wells Fargo Advisors Financial Network, LLC •  Wells Fargo Clearing Services LLC

* An affiliate of Ameriprise Financial.

The Distributor, the Investment Manager and/or their affiliates may enter into similar arrangements with other Financial Intermediaries from time to time. Therefore, the preceding list is subject to change at any time without notice.

Other Payments

From time to time, the Distributor, from its own resources and not as a Fund expense, typically provides additional compensation to certain Financial Intermediaries that sell or arrange for the sale of shares of the Funds to the extent not prohibited by laws or the rules of any self-regulatory agency, such as the Financial Industry Regulatory Authority (FINRA). Such compensation provided by the Distributor includes financial assistance to Financial Intermediaries that enable the Distributor to participate in and/or present at Financial Intermediary-sponsored conferences or seminars, sales or training programs for invited registered representatives and other Financial Intermediary employees, Financial Intermediary entertainment and other Financial Intermediary-sponsored events, and travel expenses, including lodging incurred by registered representatives and other employees in connection with prospecting, retention and due diligence trips. The Distributor makes payments for entertainment events it deems appropriate, subject to the Distributor’s internal guidelines and applicable law. These payments may vary depending upon the nature of the event.

Your Financial Intermediary may charge you fees or commissions in addition to those disclosed in this SAI. You should consult with your Financial Intermediary and review carefully any disclosure your Financial Intermediary provides regarding its services and compensation. Depending on the financial arrangement in place at any particular time, a Financial Intermediary and its financial consultants may have a financial incentive for recommending a particular Fund or a particular share class over other funds or share classes. See Investment Advisory and Other Services — Other Roles and Relationships of Ameriprise Financial and its Affiliates — Certain Conflicts of Interest for more information.

Performance Disclosure

Effective beginning with performance reporting for the December 31, 2011 year end, in presenting performance information for newer share classes, if any, of a Fund, the Fund typically includes, for periods prior to the offering of such share classes, the performance of the Fund’s oldest share class (except as otherwise disclosed), adjusted to reflect any higher class-related operating expenses of the newer share classes, as

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applicable, based on the expense ratios of those share classes for the Fund’s most recently completed fiscal year for which data was available at December 31, 2011 or, for funds and classes first offered after January 1, 2011, the expected expense differential at the time the newer share class is first offered. Actual expense differentials across classes will vary over time. The performance of the Fund’s newer share classes would have been substantially similar to the performance of the Fund’s oldest share class because all share classes of a Fund are invested in the same portfolio of securities, and would have differed only to the extent that the classes do not have the same sales charges and/or expenses (although differences in expenses between share classes may change over time).

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CAPITAL STOCK AND OTHER SECURITIES

Description of the Trust’s Shares

The Funds offer shares in the classes shown in the table below, each of which has different fees and expenses and other features. Subject to certain limited exceptions discussed in each Fund’s prospectus, a Fund or share class may no longer be accepting new investments from current shareholders or prospective investors. A Fund may, at any time and without notice, offer or stop offering any share class to the general public for investment.

The Trust’s Declaration of Trust permits it to issue an unlimited number of full and fractional shares of beneficial interest of each Fund, without par value, and to divide or combine the shares of any series into a greater or lesser number of shares of that Fund without thereby changing the proportionate beneficial interests in that Fund and to divide such shares into classes. Each share of a class of a Fund represents an equal proportional interest in that Fund with each other share in the same class and is entitled to such distributions out of the income earned on the assets belonging to that Fund as are declared in the discretion of the Board. However, different share classes of a Fund pay different distribution amounts because each share class has different expenses. Each time a distribution is made, the NAV of the share class is reduced by the amount of the distribution.

Share Classes Offered by the Funds

Fund	Class A	Class Adv	Class C	Class Inst(1)	Class Inst2(2)	Class Inst3(3)	Class R
Columbia Acorn Fund	✓	✓	✓	✓	✓	✓	—
Columbia Acorn International	✓	✓	✓	✓	✓	✓	✓
Columbia Acorn USA	✓	✓	✓	✓	✓	✓	—
Columbia Acorn International Select	✓	✓	✓	✓	✓	✓	—
Columbia Acorn European Fund	✓	✓	✓	✓	✓	✓	—
Columbia Thermostat Fund	✓	✓	✓	✓	✓	✓	—

⁽¹⁾  Financial Intermediaries that clear Fund share transactions through designated Financial Intermediaries and their mutual fund trading platforms that were given specific written notice from the Transfer Agent of the termination, effective March 31, 2013, of their eligibility for new purchases of Class Inst shares and omnibus retirement plans are no longer permitted to establish new Class Inst accounts, subject to certain exceptions. Omnibus retirement plans that opened and, subject to exceptions, funded a Class Inst account as of close of business on March 28, 2013, and have continuously held Class Inst shares in such account after such date, may generally continue to make additional purchases of Class Inst shares, open new Class Inst accounts and add new participants. In certain circumstances and in the sole discretion of the Distributor, omnibus retirement plans affiliated with a grandfathered plan may also open new Class Inst accounts. Accounts of Financial Intermediaries (other than omnibus retirement plans) that clear Fund share transactions for their client or customer accounts through designated Financial Intermediaries and their mutual fund trading platforms are not permitted to establish new Class Inst accounts or make additional purchases of Class Inst shares (other than through reinvestment of distributions).

⁽²⁾  Shareholders with Class Inst2 shares accounts funded before November 8, 2012 who do not satisfy the current eligibility criteria for Class Inst2 shares may not establish new Class Inst2 accounts but may continue to make additional purchases of Class Inst2 shares in existing accounts. In addition, investment advisory programs and similar programs that opened a Class Inst2 account as of May 1, 2010, and continuously hold Class Inst2 shares in such account after such date, may generally not only continue to make additional purchases of Class Inst2 shares but also open new Class Inst2 accounts and add new shareholders in the program.

⁽³⁾  Shareholders with Class Inst3 shares accounts funded before November 8, 2012 who do not satisfy the current eligibility criteria for Class Inst3 shares may not establish new accounts but may continue to make additional purchases of Class Inst3 shares in existing accounts.

Restrictions on Holding or Disposing of Shares

There are no restrictions on the right of shareholders to retain or dispose of the Funds’ shares, other than the possible future termination of the Funds. The Funds may be terminated by reorganization into another mutual fund or by liquidation and distribution of their assets. Unless terminated by reorganization or liquidation, the Fund will continue indefinitely.

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Liability

Under Massachusetts law, shareholders could, under certain circumstances, be held personally liable for the obligations of the Trust. However, the Trust’s Declaration of Trust disclaims any shareholder liability for acts or obligations of the Funds and the Trust and requires that notice of such disclaimer be given in each agreement, obligation, or instrument entered into or executed by a Fund or the Trustees. The Declaration of Trust provides for indemnification out of Fund property for all loss and expense of any shareholder held personally liable for the obligations of a Fund. Thus, the risk of a shareholder incurring financial loss on account of shareholder liability is limited to circumstances (which are considered remote) in which a Fund would be unable to meet its obligations and the disclaimer was inoperative. The risk of a Fund incurring financial loss on account of another series of the Trust also is believed to be remote, because it would be limited to circumstances in which the disclaimer was inoperative and the other series of the Trust was unable to meet its obligations.

Dividend Rights

The shareholders of a Fund are entitled to receive any dividends or other distributions declared for the Fund. No shares have priority or preference over any other shares of a Fund with respect to distributions. Distributions will be made from the assets of a Fund, and will be paid pro rata to all shareholders of the Fund (or class) according to the number of shares of the Fund (or class) held by shareholders on the record date. The amount of income dividends per share may vary between separate share classes of a Fund based upon differences in the way that expenses are allocated between share classes pursuant to a multiple class plan under Rule 18f-3 under the 1940 Act.

Voting Rights and Shareholder Meetings

As described in About the Trust, the Trust is not required to hold annual shareholder meetings, but special meetings may be called for certain purposes. The SEC has adopted many rules under the 1940 Act and the Investment Advisers Act of 1940 to strengthen fund governance and compliance oversight of mutual funds and their service providers. The Board will convene meetings of shareholders to elect trustees as required by the 1940 Act or as deemed otherwise appropriate by the Board.

The Trustees may fill any vacancies on the Board except that the Trustees may not fill a vacancy if, immediately after filling such vacancy, fewer than two-thirds of the Trustees then in office would have been elected to such office by the shareholders. In addition, at such times as fewer than a majority of the Trustees then in office have been elected to such office by the shareholders, the Trustees must call a meeting of shareholders. Trustees may be removed from office by a vote of the holders of a majority of the outstanding shares at a meeting duly called for the purpose, or otherwise as specified in the Trust’s organizational documents. Except as otherwise disclosed in a Fund’s prospectus and this SAI, the Trustees shall continue to hold office and may appoint their successors.

At any shareholders’ meetings that may be held, shareholders of all series would vote together, irrespective of series, on the election of Trustees, but each series would vote separately from the others on other matters, such as changes in the investment policies of that series or the approval of the management agreement for that series. Shares of the Fund and any other series of the Trust that may be in existence from time to time generally vote together except when required by law to vote separately by Fund or by class.

Liquidation Rights

In the event of the liquidation or dissolution of the Trust or the Funds, shareholders of the Funds are entitled to receive the assets attributable to the relevant class of shares of the Funds that are available for distribution and to a distribution of any general assets not attributable to a particular investment portfolio that are available for distribution in such manner and on such basis as the Board may determine.

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Preemptive Rights

There are no preemptive rights associated with Fund shares.

Conversion Rights

Shareholders have the right, which is subject to change by the Board, to convert or “exchange” shares of one class for another. Such right is outlined and subject to certain conditions set forth in each Fund’s prospectus.

Redemptions

Each Fund’s dividend, distribution and redemption policies can be found in its prospectus under the headings Buying, Selling and Exchanging Shares and Distributions and Taxes. The Trust may not suspend shareholders’ right of redemption or postpone payment for more than seven days unless the NYSE is closed for other than customary weekends or holidays, or if permitted by the rules of the SEC during periods when trading on the NYSE is restricted or during any emergency which makes it impracticable for the Funds to dispose of their securities or to determine fairly the value of its net assets, or during any other period permitted by order of the SEC for the protection of investors.

Sinking Fund Provisions

The Trust has no sinking fund provisions.

Calls or Assessment

All Fund shares are issued in uncertificated form only and when issued will be fully paid and non-assessable by the Trust

Conduct of the Trust’s Business

Forum Selection. The Trust’s Bylaws provide that the sole and exclusive forums for any shareholder (including a beneficial owner of shares) to bring (i) any action or proceeding brought on behalf of the Trust, (ii) any action asserting a claim for breach of a fiduciary duty owed by any Trustee, officer or employee, if any, of the Trust to the Trust or the Trust’s shareholders, (iii) any action asserting a claim against the Trust or any of its Trustees, officers or employees arising pursuant to any provision of the Massachusetts Business Corporation Act, the Massachusetts Uniform Trust Code or the Trust’s Declaration of Trust or Bylaws, or (iv) any action asserting a claim against the Trust or any of its Trustees, officers or employees, if any, governed by the internal affairs doctrine, shall be the federal or state courts sitting within the Commonwealth of Massachusetts. This forum selection provision may limit a shareholder’s ability to bring a claim in a judicial forum that the shareholder finds favorable or convenient for disputes with the Trust and/or any of its Trustees, officers, employees or service providers. If a court were to find the forum selection provision contained in the Bylaws to be inapplicable or unenforceable in an action, the Trust may incur additional costs associated with resolving such action in other jurisdictions.

Derivative and Direct Claims of Shareholders. The Trust’s Declaration of Trust and Bylaws contain provisions regarding derivative and direct claims of shareholders. As used in the Bylaws, a “direct” shareholder claim shall refer to: (i) a claim based upon alleged violations of a shareholder’s individual rights independent of any harm to the Trust, including a shareholder’s voting rights under the Declaration of Trust, rights to receive a dividend payment as may be declared from time to time, rights to inspect books and records, or other similar rights personal to the shareholder and independent of any harm to the Trust; and (ii) a claim for which a direct shareholder action is provided under the U.S. federal securities laws. Any other claim asserted by a shareholder, including without limitation any claims purporting to be brought on behalf of the Trust or involving any alleged harm to the Trust, shall be considered a “derivative” claim as used in the Bylaws. The Trustees of the Trust shall

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consider any such direct or derivative demand or request within 90 days of its receipt by the Trust. In their sole discretion, the Trustees may submit the matter to a vote of shareholders of the Trust or of a Fund. Any decision by the Trustees to settle or to authorize (or not to settle or to authorize) such court action, proceeding or claim, or to submit the matter to a vote of shareholders, shall be binding upon the shareholder seeking authorization. Any person purchasing or otherwise holding any interest in shares of beneficial interest of the Trust will be deemed to have notice of and consented to the foregoing provisions. These provisions may limit a shareholder’s ability to bring a claim against the Trustees, officers or other employees of the Trust and/or its service providers. For a complete discussion of derivative and direct claims of shareholders, please consult the Trust’s Bylaws, which are included as an exhibit to Part C of the Funds’ registration statement.

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PURCHASE, REDEMPTION AND PRICING OF SHARES

Purchase and Redemption

An investor may buy, sell and exchange shares in the Funds utilizing the methods, and subject to the restrictions, described in the Funds’ prospectuses. The following information supplements the information in the Funds’ prospectuses.

The Funds have authorized one or more broker-dealers to accept buy and sell orders on the Funds’ behalf. These broker-dealers are authorized to designate other intermediaries to accept buy and sell orders on the Funds’ behalf. The Funds will be deemed to have received a buy or sell order when an authorized broker-dealer, or, if applicable, a broker-dealer’s authorized designee, accepts the order. Customer orders will be priced at each Fund’s NAV next computed after they are accepted by an authorized broker-dealer or the broker’s authorized designee.

The Trust also may honor redemption requests with in-kind distributions of readily marketable securities or other property if it is appropriate to do so in light of the Trust’s responsibilities under the 1940 Act.

Under the 1940 Act, the Funds may suspend the right of redemption or postpone the date of payment for shares during any period when (i) trading on the NYSE is restricted by applicable rules and regulations of the SEC; (ii) the NYSE is closed for other than customary weekend and holiday closings; (iii) the SEC has by order permitted such suspension; (iv) an emergency exists as determined by the SEC. (The Funds may also suspend or postpone the recordation of the transfer of their shares upon the occurrence of any of the foregoing conditions).

The Trust has elected to be governed by Rule 18f-1 under the 1940 Act, as a result of which each Fund is obligated to redeem shares, subject to the exceptions listed above, with respect to any one shareholder during any 90-day period, solely in cash up to the lesser of $250,000 or 1% of the NAV of each Fund at the beginning of the period.

The Trust does not have any arrangements with shareholders or other individuals that would permit frequent purchases or redemptions of Fund shares.

The timing and magnitude of cash inflows from investors buying Fund shares could prevent a Fund from always being fully invested. Conversely, the timing and magnitude of cash outflows to investors redeeming Fund shares could require large ready reserves of uninvested cash to meet shareholder redemptions. Either situation could adversely impact a Fund’s performance.

Potential Adverse Effects of Large Investors

For information regarding the potential adverse effects of large investors in the Fund, see ABOUT THE FUNDS’ INVESTMENTS — Information Regarding Risks — Large Fund Investor Risk.

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Privileges of Insurance Company Separate Accounts

Class A shares of a Fund may be sold to an insurance company separate account without the imposition of a front-end sales charge provided that the following conditions are met:

• The insurance company separate account is either (i) structured as a pool of IRA accounts managed by a sponsoring insurance company or (ii) for the benefit of group retirement plans;

• The sponsoring insurance company makes shares of the Fund available to its contract owners/investors without the imposition of a sales charge; and

• The sponsoring insurance company provides services to the investors in the insurance company separate account, including recordkeeping and administrative services, for which the sponsoring insurance company would be compensated by the Trust’s service providers and not by the Fund.

Additional Information about Investing in the Funds

Refer to the Funds’ prospectuses for details regarding how to buy, sell and exchange shares of the Funds.

The investment minimums for the Funds’ various share classes are set forth in the Funds’ prospectuses. Additional information about each of the Funds’ share classes and choosing among them is set forth in Appendix S.

Anti-Money Laundering Compliance

The Funds are required to comply with various anti-money laundering laws and regulations. Consequently, the Funds may request additional required information from you to verify your identity. Your application will be rejected if it does not contain your name, social security number, date of birth and permanent street address. If at any time the Funds believe a shareholder may be involved in suspicious or unusual activity, or if certain account information matches information on government lists of suspicious persons, the Funds may choose not to establish a new account or may be required to “freeze” a shareholder’s account. The Funds also may be required to provide a governmental agency with information about transactions that have occurred in a shareholder’s account or to transfer monies received to establish a new account, transfer an existing account or transfer the proceeds of an existing account to a governmental agency. In some circumstances, the law may not permit the Funds to inform the shareholder that it has taken the actions described above.

Offering Price

The share price of each Fund is based on each Fund’s net asset value (NAV) per share, which is calculated separately for each class of shares as of the end of the Business Day. The NYSE is generally open Monday through Friday and is closed for weekends and the following holidays: New Year’s Day, Martin Luther King, Jr. Day, Presidents’ Day, Good Friday, Memorial Day, Juneteenth National Independence Day, Independence Day, Labor Day, Thanksgiving Day, and Christmas Day.

The value of each Fund’s portfolio securities is determined in accordance with the Funds’ Portfolio Pricing Policy and the Investment Manager’s Pricing Procedures (together, the “Pricing Policy and Procedures”), which are approved by the Board. The Board has appointed the Investment Manager to manage and implement the day-to-day valuation of Fund portfolio securities, including by making actual calculations and carrying out supervisory and certain other functions relating to the valuation of Fund portfolio securities. As described under the heading Fair Valuation of Portfolio Securities below, Fund positions for which market quotations are not readily available are valued at a fair value as determined in good faith by the valuation committee of the Investment Manager, using consistently applied procedures. The Board has authorized the valuation committee of the Investment Manager to make fair valuation decisions for the Funds pursuant to the standards, guidelines and methodologies set forth in the Pricing Policy and Procedures, and subject to the oversight and supervision of

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the Board. The Board has approved the methodologies and procedures, as set forth in the Pricing Policy and Procedures, used by the Investment Manager and its valuation committee in valuing Fund portfolio securities. Principal valuation methodologies employed by the Funds are as follows:

Domestic Equity Securities; Portfolio Companies. To calculate the NAV on a given day, a Fund generally values each security in its portfolio for which a market quotation is readily available at the latest sale price quoted for the security that day on its principal exchange. If there are no sales that day, a Fund generally values the security at the mean of the latest bid and ask quotations. If a security is traded on NASDAQ, the security is priced using the SEC approved NASDAQ official closing price, or, if there are no sales, the security is priced at the mean of the closing bid and ask quotations. The Investment Manager’s valuation committee values securities which have halted or temporarily stopped trading at the last sale price, adjusted by a premium or discount to account for the anticipated re-opening price. The Investment Manager’s valuation committee values securities for which there is no bid or ask prices. Equity securities that are not listed on any national exchange or NASDAQ are generally valued at the last sale price. Shares of open-end investment companies (other than ETFs but including the Portfolio Funds in which Columbia Thermostat Fund invests) are valued at the latest NAV reported by those companies. The Portfolio Funds generally value securities in their portfolios for which market quotations are readily available at the current market values of those securities (as determined by the policies of each Portfolio Fund) and all other securities and assets at fair value pursuant to methods established in good faith by the board of directors or trustees of each Portfolio Fund.

Foreign Equity Securities. Certain of the Funds and the Portfolio Funds may invest in securities that are primarily listed on foreign exchanges. Foreign securities are generally priced at the last sale price on the primary foreign exchange or may be priced using the closing price. However, because of differences in time zones between the United States and foreign securities markets, the prices of foreign securities may not fully reflect events that impact their current value. Generally, trading in foreign securities is substantially completed each day at various times prior to the time at which the Fund’s NAV is calculated and the values of the foreign securities used in determining the NAV are computed as of such different times. Foreign securities markets are sometimes open on days when U.S. markets are closed and the Fund’s NAV is not calculated. Although the value of foreign securities owned by the Funds could change on days when Fund shares cannot be bought or sold, Fund NAVs are not calculated, and therefore a Fund’s foreign holdings are not priced, on such days. In addition, foreign securities markets may be closed on days when U.S. markets are open and the Fund’s NAV is calculated. This means that the NAV may be based on prices for the underlying foreign securities that are not current. If appropriate, the Investment Manager’s valuation committee may determine the fair value. In addition, the Funds utilize a statistical fair valuation process to adjust prices of the foreign securities under certain circumstances. See Fair Valuation of Portfolio Securities below.

Foreign Currencies; Forward Foreign Currency Contracts. The values of foreign securities quoted in foreign currencies are translated into U.S. dollars at the intraday spot rate provided by the data service set forth in the Pricing Policy and Procedures. Forward foreign currency contracts are valued in U.S. dollars based on the intraday spot rate as of the NYSE close, adjusted by the forward points as of the time of pricing quoted by the data service specified in the Pricing Policy and Procedures.

Fair Valuation of Portfolio Securities

Rather than using the methods described above, in the event that price quotations or valuations are not readily available or are deemed unreliable, the security will be valued in good faith based on a determination of the security’s fair value pursuant to the Pricing Policy and Procedures approved by the Board. For example, a security may be fair valued when trading is halted or if the security is not actively traded, such as is the case with restricted, illiquid and nonpublic securities. The fair value of a security is likely to be different from the quoted or published price, and fair value determinations often require significant judgment.

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Fair values of securities are determined by the Investment Manager’s valuation committee following the Pricing Policy and Procedures, utilizing the valuation methodology set forth in the Pricing Policy and Procedures and deemed most appropriate in the circumstances and considering all available, relevant factors and indications of value in reaching its decision. To the extent a factor is deemed relevant, the following non-exhaustive list of factors may be used in reaching a fair value determination for a security under the Pricing Policy and Procedures: the value of other financial instruments, including derivative securities, traded on other markets or among dealers; trading volumes on markets, exchanges, or among dealers; values of baskets of securities traded on other markets, exchanges, or among dealers; changes in interest rates; observations from financial institutions; government (domestic or foreign) actions or pronouncements; other news events; and, with respect to securities traded in foreign markets, the value of foreign securities traded in other foreign markets, ADR trading, closed-end fund trading, foreign currency exchange activity, and the trading prices of financial products that are tied to baskets of foreign securities, such as WEBS. Significant events occurring after the close of a foreign exchange but before the time at which a Fund calculates the price of its foreign portfolio securities may lead to a determination that it is appropriate to fair value the affected foreign securities. Such significant events affecting a foreign security may include, but are not limited to: (i) extraordinary corporate events such as a reorganization, redemption, conversion; (ii) a trading halt in a domestic or foreign exchange; (iii) stale prices; (iv) suspension of trading in an individual security or market; (v) extraordinary market, economic or political events; (vi) scheduled and unscheduled foreign market closures; and (vii) such other instances as the Investment Manager or its valuation committee may determine in keeping with the Portfolio Pricing Policy and Procedures approved by the Board.

In addition, a statistical fair valuation process is applied daily to adjust prices of foreign securities traded on foreign exchanges in time zones different from the United States utilizing the services of a designated pricing vendor, regardless of market movement. The vendor employs a regression fair value methodology, and the Investment Manager utilizes the statistically derived fair value price for a security only when the vendor has determined that the security’s modeling factors have a 90% or greater probability of being related to the statistically fair valued price. Although the use of statistical fair valuation is intended to and may decrease opportunities for time zone arbitrage transactions, there can be no assurance that it will successfully decrease arbitrage opportunities.

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TAXATION

The following information supplements and should be read in conjunction with the section in the Funds’ prospectuses entitled Distributions and Taxes. The prospectuses generally describe the U.S. federal income tax treatment of distributions by the Funds. This section of the SAI provides additional information concerning U.S. federal income taxes. It is based on the Code, applicable U.S. Treasury Regulations, judicial authority, and administrative rulings and practice, all as in effect as of the printing of this SAI, and all of which are subject to change, including changes with retroactive effect. Except as specifically set forth below, the following discussion does not address state, local or foreign tax matters. The Funds may or may not invest in all of the securities or other instruments described in this Taxation section. Please see the Funds’ prospectuses for information about a Fund’s investments, as well as each Fund’s semiannual and annual shareholder reports.

A shareholder’s tax treatment may vary depending upon his or her particular situation. This discussion applies only to shareholders holding Fund shares as capital assets within the meaning of the Code. Except as otherwise noted, it may not apply to certain types of shareholders who may be subject to special rules, such as insurance companies, tax-exempt organizations, shareholders holding Fund shares through tax-advantaged accounts (such as 401(k) Plan Accounts, Individual Retirement Accounts, variable annuity contracts or variable life insurance contracts), financial institutions, broker-dealers, entities that are not organized under the laws of the United States or a political subdivision thereof, persons who are neither citizens nor residents of the United States, shareholders holding Fund shares as part of a hedge, straddle, or conversion transaction, shareholders who are subject to the federal alternative minimum tax, trusts, estates, pass-through entities or investors in such entities, “controlled foreign corporations,” “passive foreign investment companies,” persons eligible for benefits under an income tax treaty to which the United States is a party, or persons otherwise subject to special treatment under the Code. Investors investing through variable annuity contracts and variable life insurance policies should be aware that an investment in the Fund is expected to be treated as one investment for purposes of the “adequate diversification” requirements of Code Section 817 and the Treasury Regulations thereunder. Such investors are encouraged to consult their tax advisors and financial planners as to the tax consequences of investing in the Fund, including any potential adverse impact on the favorable tax treatment of their variable contract or policy.

The Trust has not requested and will not request an advance ruling from the IRS as to the U.S. federal income tax matters described below. The IRS could adopt positions contrary to those discussed below and such positions could be sustained. In addition, the following discussion and the discussions in the prospectuses applicable to each shareholder address only some of the U.S. federal income tax considerations generally affecting investments in the Funds. Prospective shareholders are urged to consult with their own tax advisors and financial planners regarding the U.S. federal tax consequences of an investment in a Fund, the application of state, local, or foreign laws, and the effect of any possible changes in applicable tax laws on their investment in the Funds.

Qualification as a Regulated Investment Company

It is intended that each Fund qualify as a “regulated investment company” under Subchapter M of Subtitle A, Chapter 1 of the Code. Each Fund will be treated as a separate entity for U.S. federal income tax purposes. Thus, the provisions of the Code applicable to regulated investment companies generally will apply separately to each Fund, even though each Fund is a series of the Trust. Furthermore, each Fund will separately determine its income, gains, losses, and expenses for U.S. federal income tax purposes.

In order to qualify for the special tax treatment accorded regulated investment companies and their shareholders under the Code, each Fund must, among other things, derive at least 90% of its gross income each taxable year generally from (i) dividends, interest, certain payments with respect to securities loans, gains from the sale or other disposition of stock, securities or foreign currencies, and other income attributable to its business of investing in such stock, securities or foreign currencies (including, but not limited to, gains from options, futures or forward contracts) and (ii) net income derived from an interest in a qualified publicly traded

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partnership, as defined below. In general, for purposes of this 90% gross income requirement, income derived from a partnership (other than a qualified publicly traded partnership) will be treated as qualifying income only to the extent such income is attributable to items of income of the partnership which would be qualifying income if realized directly by the regulated investment company. However, 100% of the net income derived from an interest in a qualified publicly traded partnership (defined as a partnership that (a) the interests in which are traded on an established securities market or readily tradable on a secondary market or the substantial equivalent thereof, (b) that derives at least 90% of its gross income from the passive income sources defined in Code Section 7704(d), and (c) that derives less than 90% of its income from the qualifying income described in clause (i) above) will be treated as qualifying income. In general, such entities will be treated as partnerships for federal income tax purposes if they meet the passive-type income requirement under Code Section 7704(c)(2). Certain of a Fund’s investments in master limited partnerships (MLPs) and ETFs, if any, may qualify as interests in qualified publicly traded partnerships. In addition, although in general the passive loss rules do not apply to a regulated investment company, such rules do apply to a regulated investment company with respect to items attributable to an interest in a qualified publicly traded partnership.

Each Fund must also diversify its holdings so that, at the end of each quarter of the Fund’s taxable year: (i) at least 50% of the fair market value of its total assets consists of (A) cash and cash items (including receivables), U.S. Government securities and securities of other regulated investment companies, and (B) other securities, limited in respect of any one issuer (other than those described in clause (A)) to the extent such securities do not exceed 5% of the value of the Fund’s total assets and are not more than 10% of the outstanding voting securities of such issuer, and (ii) not more than 25% of the value of the Fund’s total assets is invested in, including through corporations in which the Fund owns a 20% or more voting stock interest, the securities of any one issuer (other than those described in clause (i)(A)), the securities (other than securities of other regulated investment companies) of two or more issuers the Fund controls and which are engaged in the same, similar, or related trades or businesses, or the securities of one or more qualified publicly traded partnerships. In addition, for purposes of meeting this diversification requirement, the term “outstanding voting securities of such issuer” includes the equity securities of a qualified publicly traded partnership and in the case of a Fund’s investments in loan participations, the Fund shall treat both the financial intermediary and the issuer of the underlying loan as an issuer. The qualifying income and diversification requirements described above may limit the extent to which a Fund can engage in certain derivative transactions, as well as the extent to which it can invest in MLPs.

In addition, each Fund generally must distribute to its shareholders at least 90% of its investment company taxable income for the taxable year, which generally includes its ordinary income and the excess of any net short-term capital gain over net long-term capital loss, and at least 90% of its net tax-exempt interest income (if any) for the taxable year.

If a Fund qualifies as a regulated investment company that is accorded special tax treatment, it generally will not be subject to U.S. federal income tax on any of the investment company taxable income and net capital gain (i.e., the excess of net long-term capital gain over net short-term capital loss) it distributes to its shareholders. Each Fund generally intends to distribute at least annually substantially all of its investment company taxable income (computed without regard to the dividends-paid deduction) and its net capital gain. However, no assurance can be given that a Fund will not be subject to U.S. federal income taxation. Any investment company taxable income or net capital gain retained by a Fund will be subject to tax at regular corporate rates.

If a Fund retains any net capital gain, it will be subject to a tax at regular corporate rates on the amount retained, but may designate the retained amount as undistributed capital gains in a timely notice to its shareholders, who (i) will be required to include in income for U.S. federal income tax purposes, as long-term capital gain, their shares of such undistributed amount, and (ii) will be entitled to credit their proportionate shares of the tax paid by the Fund on such undistributed amount against their U.S. federal income tax liabilities, if any, and to claim refunds to the extent the credit exceeds such liabilities. For U.S. federal income tax purposes, the tax basis of shares owned by a shareholder of a Fund will be increased by an amount equal under current law to the

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difference between the amount of undistributed capital gains included in the shareholder’s gross income under clause (i) of the preceding sentence and the tax deemed paid by the shareholder under clause (ii) of the preceding sentence.

In determining its net capital gain, including in connection with determining the amount available to support a Capital Gain Dividend (as defined below), its taxable income, and its earnings and profits, a regulated investment company generally may elect to treat part or all of any post-October capital loss (defined as the greatest of net capital loss, net long-term capital loss, or net short-term capital loss, in each case attributable to the portion, if any, of the taxable year after October 31) or late-year ordinary loss (generally, (i) net ordinary loss from the sale, exchange or other taxable disposition of property, attributable to the portion, if any, of the taxable year after October 31 and its (ii) other net ordinary loss attributable to the portion, if any, of the taxable year after December 31) as if incurred in the succeeding taxable year.

In order to comply with the distribution requirements described above applicable to regulated investment companies, a Fund generally must make the distributions in the same taxable year in which it realizes the income and gain, although in certain circumstances, a Fund may make the distributions in the following taxable year in respect of income and gains from the prior taxable year. Shareholders generally are taxed on any net distributions from a Fund in the year they are actually distributed. If a Fund declares a distribution to shareholders of record in October, November or December of one calendar year and pays the distribution by January 31 of the following calendar year, however, the Fund and its shareholders will be treated as if the Fund paid the distribution by December 31 of the earlier year.

If the Fund were to fail to meet the income, diversification or distribution tests described above, the Fund could in some cases cure such failure including by paying a fund-level tax or interest, making additional distributions, or disposing of certain assets. If the Fund were ineligible to or otherwise did not cure such failure for any year, or were otherwise to fail to qualify and be eligible for treatment as a regulated investment company accorded special tax treatment under the Code, it would be taxed in the same manner as an ordinary corporation without any deduction for its distributions to shareholders. In this case, all distributions from the Fund’s current and accumulated earnings and profits (including any distributions of its net tax-exempt income and net long-term capital gains) to its shareholders would be taxable to shareholders as dividend income. In addition, the Fund could be required to recognize unrealized gains, pay substantial taxes and interest and make substantial distributions before requalifying as a regulated investment company.

Excise Tax

If a Fund fails to distribute by December 31 of each calendar year at least the sum of 98% of its ordinary income for that year (excluding capital gains and losses) and 98.2% of its capital gain net income (adjusted for net ordinary losses) for the one-year period ending on October 31 of that year (or November 30 or December 31 of that year if the Fund is permitted to elect and so elects), and any of its ordinary income and capital gain net income from previous years that were not distributed during such years, the Fund will be subject to a nondeductible 4% excise tax on the undistributed amounts. For these purposes, ordinary gains and losses from the sale, exchange, or other taxable disposition of property that would be properly taken into account after October 31 of a calendar year (or November 30 if the Fund makes the election described above) are generally treated as arising on January 1 of the following calendar year; in the case of a Fund with a December 31 year end that makes the election described above, no such gains or losses will be so treated. For purposes of the excise tax, a Fund will be treated as having distributed any amount on which it has been subject to corporate income tax in the taxable year ending within the calendar year. Each Fund generally intends to actually distribute or be deemed to have distributed substantially all of its ordinary income and capital gain net income, if any, by the end of each calendar year and, thus, expects not to be subject to the excise tax. However, no assurance can be given that a Fund will not be subject to the excise tax. Moreover, each Fund reserves the right to pay an excise tax rather than make an additional distribution when circumstances warrant (for example, if the amount of excise tax to be paid is deemed de minimis by a Fund).

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Capital Loss Carryovers

Capital losses in excess of capital gains (“net capital losses”) are not permitted to be deducted against a Fund’s net investment income. Instead, subject to certain limitations, a Fund is able to carry forward a net capital loss from any taxable year to offset its capital gains, if any, realized during a subsequent taxable year. Capital loss carry forwards are reduced to the extent they offset current-year net realized capital gains whether the Fund retains or distributes such gains. A Fund may carry net capital losses forward to one or more subsequent taxable years without expiration; any such carryover losses will retain their character as short-term or long-term. The Fund must apply such carryforwards first against gains of the same character. Capital gains that are offset by carried forward capital losses are not subject to fund-level U.S. federal income taxation, regardless of whether they are distributed to shareholders. Accordingly, the Funds do not expect to distribute any capital gains so offset. The Funds cannot carry back or carry forward any net operating losses.

Fund	Total Capital Loss Carryover		Amount Not Expiring
			Short term		Long term
Columbia Acorn Fund		—		—		—
Columbia Acorn International	$	73,745,642	$	47,476,543	$	26,269,099
Columbia Acorn USA		—		—		—
Columbia Acorn International Select		—		—		—
Columbia Acorn European Fund	$	2,471,500	$	2,471,500		—
Columbia Thermostat Fund		—		—		—

Equalization Accounting

Each Fund may use the so-called “equalization method” of accounting to allocate a portion of its “accumulated earnings and profits,” which generally equals a Fund’s undistributed net investment income and realized capital gains, with certain adjustments, to redemption proceeds. This method permits a Fund to achieve more balanced distributions for both continuing and redeeming shareholders. Although using this method generally will not affect a Fund’s total returns, it may reduce the amount of income and gains that the Fund would otherwise distribute to continuing shareholders by reducing the effect of redemptions of Fund shares on Fund distributions to shareholders. The IRS has not sanctioned the particular equalization method used by the Funds, and thus a Fund’s use of this method may be subject to IRS scrutiny.

Taxation of Fund Investments

In general, realized gains or losses on the sale of securities held by a Fund will be treated as capital gains or losses, and long-term capital gains or losses if the Fund has held or is deemed to have held the securities for more than one year at the time of disposition.

For federal income tax purposes, debt securities purchased by the Funds may be treated as having original issue discount (“OID”), which is generally treated as interest for federal income tax purposes. If a Fund purchases a debt obligation with OID (generally a debt obligation with an issue price less than its stated principal amount, such as a zero-coupon bond), which exceeds a de minimis amount, the Fund may be required to annually include in its income a portion of the OID as ordinary income, even though the Fund will not receive cash payments for such discount until maturity or disposition of the obligation, and depending on market conditions and the credit quality of the bond, might not ever receive cash for such discount. OID on tax-exempt bonds is generally not subject to U.S. federal income tax (but may be subject to the U.S. federal alternative minimum tax or “AMT,” as that term is defined below). Inflation-protected bonds generally can be expected to produce OID income as their principal amounts are adjusted upward for inflation.

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If a Fund invests in debt obligations that are in the lowest rating categories or are unrated, including debt obligations of issuers not currently paying interest or who are in default, special tax issues may exist for the Fund. Tax rules are not entirely clear about issues, such as whether a Fund should recognize market discount on a debt obligation and, if so, the amount of market discount the Fund should recognize, when a Fund may cease to accrue interest, OID or market discount, when and to what extent deductions may be taken for bad debts or worthless securities and how payments received on obligations in default should be allocated between principal and income. These and other related issues will be addressed by a Fund when, as and if it invests in such securities, in order to seek to ensure that it distributes sufficient income to preserve its status and eligibility for treatment as a regulated investment company and does not become subject to U.S. federal income or excise tax.

Very generally, when a Fund or a Portfolio Fund purchases a bond at a price that exceeds the redemption price at maturity — that is, at a premium — the premium is amortizable over the remaining term of the bond. In the case of a taxable bond, if a Fund or a Portfolio Fund makes an election applicable to all such bonds it purchases, which election cannot be revoked without consent of the IRS, the Fund or the Portfolio Fund reduces the current taxable interest income from the bond by the amortized premium and reduces its basis in the bond by the amount of such offset; upon the disposition or maturity of such bonds acquired on or after January 4, 2013, a Fund or a Portfolio Fund is permitted to deduct any remaining premium allocable to a prior period. In the case of a tax-exempt bond, tax rules require a Fund or a Portfolio Fund to reduce its tax basis by the amount of the amortized premium.

If an option granted by a Fund is sold, lapses or is otherwise terminated through a closing transaction, such as a repurchase by the Fund of the option from its holder, the Fund generally will realize a short-term capital gain or loss, depending on whether the premium income is greater or less than the amount paid by the Fund in the closing transaction, unless the option is subject to Section 1256 of the Code, described below. Some capital losses realized by a Fund in the sale, exchange, exercise or other disposition of an option may be deferred if they result from a position that is part of a “straddle,” discussed below. If securities are sold by a Fund pursuant to the exercise of a covered call option granted by it, the Fund generally will add the premium received to the sale proceeds of the securities delivered in determining the amount of gain or loss on the sale. If securities are purchased by a Fund pursuant to the exercise of a put option written by it, the Fund generally will subtract the premium received from its cost basis in the securities purchased.

Some regulated futures contracts, foreign currency contracts, and non-equity, listed options that may be used by a Fund will be deemed “Section 1256 contracts.” A Fund will be required to “mark to market” any such contracts held at the end of the taxable year by treating them as if they had been sold on the last day of that year at market value. Sixty percent of any net gain or loss realized on all dispositions of Section 1256 contracts, including deemed dispositions under the “mark-to-market” rule, generally will be treated as long-term capital gain or loss, and the remaining 40% will be treated as short-term capital gain or loss, although certain foreign currency gains and losses from such contracts may be treated as entirely ordinary income or loss as described below. These provisions may require a Fund to recognize income or gains without a concurrent receipt of cash. Transactions that qualify as designated hedges are exempt from the mark-to-market rule and the “60%/40%” rule and may require the Fund to defer the recognition of losses on certain futures contracts, foreign currency contracts, and non-equity options.

Foreign exchange gains and losses realized by a Fund in connection with certain transactions involving foreign currency-denominated debt securities, certain options, futures contracts, forward contracts and similar instruments relating to foreign currencies, or payables or receivables denominated in a foreign currency are subject to Section 988 of the Code, which generally causes such gains and losses to be treated as ordinary income or loss and may affect the amount and timing of recognition of the Fund’s income. Under future U.S. Treasury Regulations, any such transactions that are not directly related to a Fund’s investments in stock or securities (or its options contracts or futures contracts with respect to stock or securities) may have to be limited in order to enable the Fund to satisfy the 90% qualifying income test described above. If the net foreign exchange loss

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exceeds a Fund’s net investment company taxable income (computed without regard to such loss) for a taxable year, the resulting ordinary loss for such year will not be available as a carryover and thus cannot be deducted by the Fund or its shareholders in future years.

Offsetting positions held by a Fund involving certain derivative instruments, such as forward, futures and options contracts, may be considered, for U.S. federal income tax purposes, to constitute “straddles.” “Straddles” are defined to include “offsetting positions” in actively traded personal property. The tax treatment of “straddles” is governed by Section 1092 of the Code which, in certain circumstances, overrides or modifies the provisions of Section 1256. If a Fund is treated as entering into a “straddle” and at least one (but not all) of the Fund’s positions in derivative contracts comprising a part of such straddle is governed by Section 1256 of the Code, described above, then such straddle could be characterized as a “mixed straddle.” A Fund may make one or more elections with respect to “mixed straddles.” Depending upon which election is made, if any, the results with respect to a Fund may differ. Generally, to the extent the straddle rules apply to positions established by a Fund, losses realized by the Fund may be deferred to the extent of unrealized gain in any offsetting positions. Moreover, as a result of the straddle rules, short-term capital loss on straddle positions may be recharacterized as long-term capital loss, and long-term capital gain may be characterized as short-term capital gain. In addition, the existence of a straddle may affect the holding period of the offsetting positions. As a result, the straddle rules could cause distributions that would otherwise constitute “qualified dividend income” or qualify for the dividends-received deduction to fail to satisfy the applicable holding period requirements (as described below). Furthermore, the Fund may be required to capitalize, rather than deduct currently, any interest expense and carrying charges applicable to a position that is part of a straddle, including any interest on indebtedness incurred or continued to purchase or carry any positions that are part of a straddle. The application of the straddle rules to certain offsetting Fund positions can therefore affect the amount, timing, and character of distributions to shareholders, and may result in significant differences from the amount, timing and character of distributions that would have been made by the Fund if it had not entered into offsetting positions in respect of certain of its portfolio securities.

If a Fund enters into a “constructive sale” of any appreciated financial position in stock, a partnership interest, or certain debt instruments, the Fund will be treated as if it had sold and immediately repurchased the property and must recognize gain (but not loss) with respect to that position. A constructive sale of an appreciated financial position occurs when a Fund enters into certain offsetting transactions with respect to the same or substantially identical property, including, but not limited to: (i) a short sale; (ii) an offsetting notional principal contract; (iii) a futures or forward contract; or (iv) other transactions identified in future Treasury Regulations. The character of the gain from constructive sales will depend upon a Fund’s holding period in the appreciated financial position. Losses realized from a sale of a position that was previously the subject of a constructive sale will be recognized when the position is subsequently disposed of. The character of such losses will depend upon a Fund’s holding period in the position beginning with the date the constructive sale was deemed to have occurred and the application of various loss deferral provisions in the Code. Constructive sale treatment does not apply to certain closed transactions, including if such a transaction is closed on or before the 30th day after the close of the Fund’s taxable year and the Fund holds the appreciated financial position unhedged throughout the 60-day period beginning with the day such transaction was closed.

The amount of long-term capital gain a Fund may recognize from certain derivative transactions with respect to interests in certain pass-through entities is limited under the Code’s constructive ownership rules. The amount of long-term capital gain is limited to the amount of such gain the Fund would have had if the Fund directly invested in the pass-through entity during the term of the derivative contract. Any gain in excess of this amount is treated as ordinary income. An interest charge is imposed on the amount of gain that is treated as ordinary income.

If the Fund makes a distribution of income received by the Fund in lieu of dividends (a “substitute payment”) with respect to securities on loan pursuant to a securities lending transaction, such income will not constitute qualified dividend income to individual shareholders and will not be eligible for the dividends-received

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deduction for corporate shareholders. Similar consequences may apply to repurchase and other derivative transactions. Similarly, to the extent that a Fund makes distributions of income received by such Fund in lieu of tax-exempt interest with respect to securities on loan, such distributions will not constitute exempt-interest dividends (defined below) to shareholders.

In addition, a Fund’s transactions in securities and certain types of derivatives (e.g., options, futures contracts, forward contracts and swap agreements) may be subject to other special tax rules, such as “wash-sale” or short-sale rules, the effect of which may be to accelerate income to the Fund, defer losses to the Fund, cause adjustments in the holding periods of the Fund’s securities, convert long-term capital gains into short-term capital gains, and/or convert short-term capital losses into long-term capital losses, cause adjustments in the holding periods of the Fund’s securities. These rules could therefore affect the amount, timing and character of distributions to shareholders.

Certain of a Fund’s investments in derivative instruments and foreign currency-denominated instruments, as well as any of its foreign currency transactions and hedging activities, are likely to produce a difference between its book income and its taxable income. If a Fund’s book income exceeds the sum of its taxable income and net tax-exempt income (if any), the distribution (if any) of such excess generally will be treated as (i) a dividend to the extent of the Fund’s remaining earnings and profits (including earnings and profits arising from tax-exempt income), (ii) thereafter, as a return of capital to the extent of the recipient’s basis in its shares, and (iii) thereafter, as gain from the sale or exchange of a capital asset. If a Fund’s book income is less than the sum of its taxable income and net tax-exempt income (if any), the Fund could be required to make distributions exceeding book income to qualify for treatment as a regulated investment company that is accorded special tax treatment.

Rules governing the U.S. federal income tax aspects of derivatives, including swap agreements and certain commodity-linked investments, are not entirely clear in certain respects. Accordingly, while each Fund intends to account for such transactions in a manner it deems to be appropriate, an adverse determination or future guidance by the IRS with respect to these rules (which determination or guidance could be retroactive) may affect whether a Fund has made sufficient distributions, and otherwise satisfied the relevant requirements to maintain its qualification as a regulated investment company and avoid fund-level tax. Certain requirements that must be met under the Code in order for a Fund to qualify as a regulated investment company may limit the extent to which a Fund will be able to engage in certain derivatives or commodity-linked transactions.

Any investment by a Fund in equity securities of a REIT may result in the Fund’s receipt of cash in excess of the REIT’s earnings; if the Fund distributes these amounts, these distributions could constitute a return of capital to Fund shareholders for U.S. federal income tax purposes. Dividends received by a Fund from a REIT generally will not constitute qualified dividend income and will not qualify for the dividends-received deduction. Distributions by a Fund to its shareholders that the Fund properly reports as “section 199A dividends,” as defined and subject to certain conditions described below, are treated as qualified REIT dividends in the hands of non-corporate shareholders. Non-corporate shareholders are permitted a federal income tax deduction equal to 20% of qualified REIT dividends received by them, subject to certain limitations. Very generally, a “section 199A dividend” is any dividend or portion thereof that is attributable to certain dividends received by a regulated investment company from REITs, to the extent such dividends are properly reported as such by the regulated investment company in a written notice to its shareholders. A section 199A dividend is treated as a qualified REIT dividend only if the shareholder receiving such dividend holds the dividend-paying regulated investment company shares for at least 46 days of the 91-day period beginning 45 days before the shares become ex dividend, and is not under an obligation to make related payments with respect to a position in substantially similar or related property. A Fund is permitted to report such part of its dividends as section 199A dividends as are eligible, but is not required to do so.

A Fund may invest directly or indirectly in residual interests in real estate mortgage investment conduits (REMICs) or equity interests in taxable mortgage pools (TMPs). Under an IRS notice, and U.S. Treasury

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Regulations that have yet to be issued but may apply retroactively, a portion of a Fund’s income (including income allocated to the Fund from a real estate investment trust (REIT), a regulated investment company or other pass-through entity) that is attributable to a residual interest in a REMIC or an equity interest in a TMP (referred to in the Code as an “excess inclusion”) will be subject to U.S. federal income tax in all events. This notice also provides, and the regulations are expected to provide, that excess inclusion income of a regulated investment company, such as a Fund, will be allocated to shareholders of the regulated investment company in proportion to the dividends received by such shareholders, with the same consequences as if the shareholders held the related interest directly. As a result, the Fund may not be a suitable investment for certain tax-exempt shareholders, as noted under Tax-Exempt Shareholders below.

In general, excess inclusion income allocated to shareholders (i) cannot be offset by net operating losses (subject to a limited exception for certain thrift institutions), (ii) will constitute unrelated business taxable income (“UBTI”) to entities (including a qualified pension plan, an individual retirement account, a 401(k) plan, a Keogh plan or certain other tax-exempt entities) subject to tax on UBTI, thereby potentially requiring such an entity that is allocated excess inclusion income, and otherwise might not be required to file a tax return, to file a tax return and pay tax on such income, and (iii) in the case of a foreign shareholder, will not qualify for any reduction in U.S. federal withholding tax.

Some amounts received by a Fund from its investments in master limited partnerships (MLPs) will likely be treated as returns of capital because of accelerated deductions available with respect to the activities of MLPs. On the disposition of an investment in such an MLP, the Fund will likely realize taxable income in excess of economic gain from that asset (or if, in later periods, a Fund does not dispose of the MLP, the Fund will likely realize taxable income in excess of cash flow received by the Fund from the MLP), and the Fund must take such income into account in determining whether the Fund has satisfied its regulated investment company distribution requirements. The Fund may have to borrow or liquidate securities to satisfy its distribution requirements and meet its redemption requests, even though investment considerations might otherwise make it undesirable for the Fund to borrow money or sell securities at the time. Any Fund distribution of income attributable to qualified publicly traded partnership income from a Fund’s investment in an MLP, will not qualify for the deduction that could be available to a non-corporate shareholder were the shareholder to own such MLP directly. In addition, distributions attributable to gain from the sale of MLPs that are characterized as ordinary income under the Code’s recapture provisions will be taxable to shareholders as ordinary income.

As noted above, certain of the ETFs and MLPs in which a Fund may invest qualify as qualified publicly traded partnerships. In such cases, the net income derived from such investments will constitute qualifying income for purposes of the 90% gross income requirement described earlier for qualification as a regulated investment company. If, however, such a vehicle were to fail to qualify as a qualified publicly traded partnership in a particular year, all or a portion of the gross income derived from it in such year could constitute non-qualifying income to a Fund for purposes of the 90% gross income requirement and thus could adversely affect the Fund’s ability to qualify as a regulated investment company for a particular year. In addition, as described above, the diversification requirement for regulated investment company qualification will limit a Fund’s investments in one or more vehicles that are qualified publicly traded partnerships to 25% of the Fund’s total assets as of the end of each quarter of the Fund’s taxable year.

“Passive foreign investment companies” (PFICs) are generally defined as foreign corporations where at least 75% of their gross income for their taxable year is income from passive sources (such as certain interest, dividends, rents and royalties, or capital gains) or at least 50% of their assets on average produce such passive income or are held for the production of such passive income. If a Fund acquires any equity interest in a PFIC, the Fund could be subject to U.S. federal income tax and interest charges on “excess distributions” received from the PFIC or on gain from the sale of such equity interest in the PFIC, even if all income or gain actually received by the Fund is timely distributed to its shareholders. Excess distributions and gain from the sale of interests in PFICs may be characterized as ordinary income even though, absent the application of PFIC rules, these amounts may otherwise have been classified as capital gain.

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A Fund will not be permitted to pass through to its shareholders any credit or deduction for these special taxes and interest charges incurred with respect to a PFIC. Elections may be available that would ameliorate these adverse tax consequences, but such elections would require a Fund to include its share of the PFIC’s income and net capital gains annually, regardless of whether it receives any distribution from the PFIC (in the case of a “QEF election”), or to mark the gains (and to a limited extent losses) in its interests in the PFIC “to the market” as though the Fund had sold and repurchased such interests on the last day of the Fund’s taxable year, treating such gains and losses as ordinary income and loss (in the case of a “mark-to-market election”). The QEF and mark-to-market elections may require a Fund to recognize taxable income or gain without the concurrent receipt of cash and increase the amount required to be distributed by the Fund to avoid taxation. Making either of these elections therefore may require a Fund to liquidate other investments prematurely to meet the minimum distribution requirements described above, which also may accelerate the recognition of gain and may affect the Fund’s total return. Each Fund may attempt to limit and/or manage its holdings in PFICs to minimize tax liability and/or maximize returns from these investments but there can be no assurance that it will be able to do so. Moreover, because it is not always possible to identify a foreign corporation as a PFIC in advance of acquiring shares in the corporation, a Fund may incur the tax and interest charges described above in some instances. Dividends paid by a foreign corporation that, for its taxable year in which the dividend is paid or the preceding taxable year, is a PFIC will not be eligible to be treated as qualified dividend income, as defined below.

A U.S. person, including a Fund, who owns (directly or indirectly) 10% or more of the total combined voting power of all classes of stock of a foreign corporation or 10% or more of the total value of shares of all classes of stock of a foreign corporation is a “U.S. Shareholder” for purposes of the controlled foreign corporation (CFC) provisions of the Code. Generally, a CFC is a foreign corporation that is owned (directly, indirectly, or constructively determined by reference to complex ownership attribution rules under the Code) more than 50% (measured by voting power or value) by U.S. Shareholders. If a Fund were a U.S Shareholder of a CFC, then the Fund may be required to recognize income with respect to the CFC before amounts are distributed to the CFC. The Fund must take such income into account in determining whether the Fund has satisfied its regulated investment company distribution requirements. The Fund may have to borrow or liquidate securities to satisfy its distribution requirements and meet its redemption requests, even though investment considerations might otherwise make it undesirable for the Fund to borrow money or sell securities at the time.

In addition to the investments described above, prospective shareholders should be aware that other investments made by a Fund may involve complex tax rules that may result in income or gain recognition by the Fund without corresponding current cash receipts. Although each Fund seeks to avoid significant noncash income, such noncash income could be recognized by a Fund, in which case the Fund may distribute cash derived from other sources in order to meet the minimum distribution requirements described above. In this regard, a Fund could be required at times to liquidate investments prematurely in order to satisfy its minimum distribution requirements, which may accelerate the recognition of gain and adversely affect the Fund’s total return.

Taxation of Distributions

Except for exempt-interest dividends (defined below) paid by a Fund, distributions paid out of a Fund’s current and accumulated earnings and profits, whether paid in cash or reinvested in the Fund, generally are deemed to be taxable distributions and must be reported by each shareholder who is required to file a U.S. federal income tax return. Dividends and distributions on a Fund’s shares are generally subject to U.S. federal income tax as described herein to the extent they do not exceed the Fund’s realized income and gains, even though such dividends and distributions may economically represent a return of a particular shareholder’s investment. Such distributions are likely to occur in respect of shares purchased at a time when the Fund’s NAV reflects either unrealized gains or realized but undistributed income or gains. Such realized income and gains may be required to be distributed even when the Fund’s NAV also reflects unrealized losses. For U.S. federal income tax purposes, a Fund’s earnings and profits, described above, are determined at the end of the Fund’s taxable year and are allocated pro rata to distributions paid over the entire year. Distributions in excess

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of a Fund’s current and accumulated earnings and profits will first be treated as a return of capital up to the amount of a shareholder’s tax basis in his or her Fund shares and then as capital gain. A return of capital is not taxable, but it reduces a shareholder’s tax basis in his or her Fund shares, thus reducing any loss or increasing any gain on a subsequent taxable disposition by the shareholder of his or her shares. A Fund may make distributions in excess of its earnings and profits to a limited extent, from time to time.

For U.S. federal income tax purposes, distributions of investment income (except for “qualified dividend income” and exempt-interest dividends, both defined below) are generally taxable as ordinary income, and distributions of gains from the sale of investments that a Fund owned (or is deemed to have owned) for one year or less will be taxable at ordinary income rates. Distributions properly reported by a Fund as capital gain dividends (Capital Gain Dividends) will be taxable to shareholders as long-term capital gain (to the extent such distributions do not exceed the Fund’s actual net long-term capital gain for the taxable year), regardless of how long a shareholder has held Fund shares, and do not qualify as dividends for purposes of the dividends-received deduction or as qualified dividend income (defined below). Each Fund will report Capital Gain Dividends, if any, in written statements furnished to its shareholders. Certain events may require a Fund to sell significant amounts of appreciated securities, and make large Capital Gain Dividends relative to the Fund’s NAV. Such events may include large net shareholder redemptions, portfolio re-balancing or fund mergers. A Fund generally provides estimates of expected Capital Gain Dividends (if any) prior to the distribution on columbiathreadneedleus.com.

The IRS and the Department of the Treasury have issued proposed regulations that would impose special rules in respect of Capital Gain Dividends received through partnership interests constituting “applicable partnership interests” under Section 1061 of the Code.

Dividends reported by a Fund as qualified dividend income are generally taxed at long-term capital gain tax rates for individual shareholders. In general, “qualified dividend income” is income attributable to dividends received by a Fund from certain domestic and foreign corporations, as long as certain holding period and other requirements are met by the Fund with respect to the dividend-paying corporation’s stock and by the Fund’s shareholders with respect to the Fund’s shares. If 95% or more of a Fund’s gross income (excluding net long-term capital gain over net short-term capital loss) constitutes qualified dividend income, all of its distributions (other than Capital Gain Dividends) will be generally treated as qualified dividend income in the hands of individual shareholders, as long as they have owned their Fund shares for at least 61 days during the 121-day period beginning 60 days before the Fund’s ex-dividend date (or, in the case of certain preferred stock, 91 days during the 181-day period beginning 90 days before such date) and meet certain other requirements specified in the Code. In general, if less than 95% of a Fund’s gross income is attributable to qualified dividend income, then only the portion of the Fund’s distributions that is attributable to qualified dividend income and reported as such in a timely manner will be so treated in the hands of individual shareholders who meet the aforementioned holding period requirements. The rules regarding the qualification of Fund distributions as qualified dividend income are complex, including the holding period requirements. Individual Fund shareholders therefore are urged to consult their own tax advisors and financial planners. Fixed income funds typically do not distribute significant amounts of qualified dividend income.

The Code generally imposes a 3.8% net investment income tax on certain high-income individuals, trusts and estates. For individuals, the 3.8% tax applies to the lesser of (1) the amount (if any) by which the taxpayer’s modified adjusted gross income exceeds certain threshold amounts or (2) the taxpayer’s “net investment income.” For this purpose, “net investment income” generally includes, among other things, (i) distributions paid by a Fund of net investment income and capital gains (other than exempt-interest dividends) as described above, and (ii) any net gain recognized on the sale, redemption, exchange or other taxable disposition of Fund shares. Certain details of the implementation of the tax remain subject to future guidance. Shareholders are advised to consult their tax advisors regarding the possible implications of this additional tax on their investment in a Fund.

As described above, if the Fund invests in REITs, the Fund may report “section 199A dividends” treated as qualified REIT dividends in the hands of non-corporate shareholders, who are permitted a federal income tax deduction equal to 20% of qualified REIT dividends received by them, subject to certain limitations.

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Some states will not tax distributions made to individual shareholders that are attributable to interest a Fund earns on direct obligations of the U.S. Government if the Fund meets the state’s minimum investment or reporting requirements, if any. Investments in GNMA or FNMA securities, bankers’ acceptances, commercial paper, and repurchase agreements collateralized by U.S. Government securities generally do not qualify for tax-free treatment. This exemption may not apply to corporate shareholders.

Sales and Exchanges of Fund Shares

Generally, if a shareholder sells or exchanges his or her Fund shares, he or she generally will realize a taxable capital gain or loss on the difference between the amount received for the shares (or deemed received in the case of an exchange) and his or her tax basis in the shares. This gain or loss will be long-term capital gain or loss if he or she has held (or is deemed to have held) such Fund shares for more than one year at the time of the sale or exchange, and short-term capital gain or loss otherwise.

If a shareholder incurs a sales charge in acquiring Fund shares and sells or exchanges those shares within 90 days of having acquired such shares and if, as a result of having initially acquired those shares, he or she subsequently pays a reduced sales charge on a new purchase of shares of the Fund or a different regulated investment company, the sales charge previously incurred in acquiring the Fund’s shares generally shall not be taken into account (to the extent the previous sales charges do not exceed the reduction in sales charges on the new purchase) for the purpose of determining the amount of gain or loss on the disposition, but generally will be treated as having been incurred in the new purchase. This sales charge basis deferral rule shall apply only when a shareholder makes such new acquisition of Fund shares or shares of a different regulated investment company during the period beginning on the date the original Fund shares are disposed of and ending on January 31 of the calendar year following the calendar year the original Fund shares are disposed of. If a shareholder realizes a loss on a disposition of Fund shares, the loss generally will be disallowed under the “wash sale” rules to the extent that he or she purchases (including through the reinvestment of dividends) substantially identical shares within the 61-day period beginning 30 days before and ending 30 days after the disposition. Any disallowed loss generally will be reflected in an adjustment to the tax basis of the purchased shares.

If a shareholder receives a Capital Gain Dividend or is deemed to receive a distribution of long-term capital gain with respect to any Fund share and such Fund share is held or treated as held for six months or less, then (unless otherwise disallowed) any loss on the sale or exchange of that Fund share will be treated as a long-term capital loss to the extent of the Capital Gain Dividend or deemed long-term capital gain distribution. If Fund shares are sold at a loss after being held for six months or less, the loss generally will be disallowed to the extent of any exempt-interest dividends (defined below) received on those shares. However, this loss disallowance does not apply with respect to redemptions of Fund shares with a holding period beginning after December 22, 2010 if such Fund declares substantially all of its net tax-exempt income as exempt-interest dividends on a daily basis, and pays such dividends on at least a monthly basis (as would typically be the case for tax-exempt money market funds).

Cost Basis Reporting

Each Fund (or the shareholder’s financial intermediary, if Fund shares are held through a Financial Intermediary) generally is required to report to shareholders and the IRS gross proceeds on sales, redemptions or exchanges of Fund shares. In addition, for shares purchased, including shares purchased through dividend reinvestment, on or after January 1, 2012, the Funds (or the shareholder’s Financial Intermediary) generally are required to provide the shareholders and the IRS, upon the sale, redemption or exchange of Fund shares, with cost basis information about those shares as well as information about whether any gain or loss is short- or long-term and whether any loss is disallowed under the “wash sale” rules. This reporting is not required for Fund shares held in a retirement or other tax-advantaged account. With respect to Fund shares in accounts held directly with a Fund, each Fund will calculate and report cost basis using the Fund’s default method of average cost, unless the shareholder instructs the Fund to use a different calculation method. A Fund will not report cost basis

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for shares whose cost basis is uncertain or unknown to the Fund. Please visit the Columbia Funds’ website at columbiathreadneedle.com/us or contact the Funds at 800.345.6611 for more information regarding average cost basis reporting and other available methods for cost basis reporting and how to select or change a particular method or to choose specific shares to sell, redeem or exchange. If a shareholder retains Fund shares through a Financial Intermediary, he or she should contact their Financial Intermediary to learn about the Fund’s cost basis reporting default method and the reporting elections available to his or her account. The Funds do not recommend any particular method of determining cost basis. The shareholder should consult a tax advisor to determine which available cost basis method is best. When completing U.S. federal and state income tax returns, shareholders should carefully review the cost basis and other information provided and make any additional basis, holding period or other adjustments that may be required.

Foreign Taxes

Amounts realized by a Fund from sources within foreign countries may be subject to withholding and other taxes imposed by such countries. Tax conventions between certain countries and the United States may reduce or eliminate such taxes. If more than 50% of the value of a Fund’s total assets at the close of its taxable year consists of securities of foreign corporations, the Fund will be eligible to file an annual election with the IRS pursuant to which the Fund may pass-through to its shareholders on a pro rata basis foreign income and similar taxes paid by the Fund with respect to foreign securities that the Fund has held for at least the minimum holding periods specified in the Code and such taxes may be claimed, subject to certain limitations, either as a tax credit or deduction by the shareholders. In some cases, a Fund may also be eligible to pass through to its shareholders the foreign taxes paid by underlying funds (as defined below) in which it invests that themselves elected to pass through such taxes to their shareholders, see Special Tax Considerations Pertaining to Funds of Funds below.

Certain Funds may qualify for and make the election; however, even if a Fund qualifies for the election for any year, it may determine not to make the election for such year. If a Fund does not so qualify or qualifies but does not so elect, then shareholders will not be entitled to claim a credit or deduction with respect to foreign taxes paid by or withheld from payments to the Fund. A Fund will notify its shareholders in written statements if it has elected for the foreign taxes paid by it to “pass through” for that year.

In general, if a Fund makes the election, the Fund itself will not be permitted to claim a credit or deduction for foreign taxes paid in that year, and the Fund’s dividends-paid deduction will be increased by the amount of foreign taxes paid that year. Fund shareholders generally shall include their proportionate share of the foreign taxes paid by the Fund in their gross income and treat that amount as paid by them for the purpose of the foreign tax credit or deduction, provided that any applicable holding period and other requirements have been met. If a shareholder claims a credit for foreign taxes paid, in general, the credit will be subject to certain limits. A deduction for foreign taxes paid may be claimed only by shareholders that itemize their deductions. Shareholders that are not subject to U.S. federal income tax, and those who invest in the Fund through tax-exempt accounts (including those who invest through IRAs or other tax-advantaged retirement plans), generally will receive no benefit from any tax credit or deduction passed through by the Fund.

If a taxpayer claims a foreign tax credit and the tax is later refunded, the taxpayer generally must notify the IRS, which redetermines the taxpayer’s U.S. income tax liability for the relevant years. The application of this rule to a Fund that has elected to pass through foreign tax credits to shareholders is not entirely clear. If a Fund receives a refund of foreign taxes paid in a prior year, the Fund may file amended income tax returns for the year or years in which such tax was paid, in which case shareholders during such year or years may owe additional tax, or, if eligible, the Fund may either (A) elect to apply the foreign tax netting approach described in Section 4 of Notice 2016-10 (or subsequently-issued regulations) with respect to such refund in the Fund’s current taxable year, or (B) request an IRS closing agreement with respect to the refund, as described in Section 5 of Notice 2016-10 (or subsequently-issued regulations). Very generally, if the foreign tax netting approach is used, the Fund would reduce the amount of foreign taxes reported to shareholders for the year in which the refund is received, thereby reducing the foreign tax credits passed through to shareholders for such year. If the Fund enters

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into an IRS closing agreement, the Fund generally will be required to pay a tax or other amount to the IRS in lieu of an amended tax return, and in satisfaction of any potential U.S. tax liability of Fund shareholders with respect to such refunded foreign tax. Therefore, this decision could affect the amount of foreign tax passed through to shareholders, and the amount of tax incurred by the Fund. The Fund is not required to distribute any foreign tax refunded.

Special Tax Considerations Pertaining to Funds of Funds

Certain Funds (each such fund, a Fund of Funds) invest their assets primarily in shares of other mutual funds, ETFs or other companies that are regulated investment companies (collectively, underlying funds). Consequently, their income and gains will normally consist primarily of distributions from underlying funds and gains and losses on the disposition of shares of underlying funds. To the extent that an underlying fund realizes net losses on its investments for a given taxable year, a Fund of Funds will not be able to benefit from those losses until (i) the underlying fund realizes gains that it can reduce by those losses, or (ii) the Fund of Funds recognizes its share of those losses (so as to offset distributions of capital gains from other underlying funds) when it disposes of shares of the underlying fund. Moreover, even when a Fund of Funds does make such a disposition, a portion of its loss may be recognized as a long-term capital loss, which will not be treated as favorably for U.S. federal income tax purposes as a short-term capital loss or an ordinary deduction. In particular, a Fund of Funds will not be able to offset any capital losses from its dispositions of underlying fund shares against its ordinary income (including distributions of any net short-term capital gains realized by an underlying fund).

In addition, in certain circumstances, the “wash sale” rules may apply to sales of underlying fund shares by a Fund of Funds. As discussed above, a wash sale occurs if shares of an underlying fund are sold by a Fund of Funds at a loss and the Fund of Funds acquires additional shares of that same underlying fund 30 days before or after the date of the sale. The rules could defer losses of a Fund of Funds on sales of underlying fund shares (to the extent such sales are wash sales) for extended (and, in certain cases, potentially indefinite) periods of time.

As a result of the foregoing rules, and certain other special rules, it is possible that the amounts of net investment income and net capital gain that a Fund of Funds will be required to distribute to shareholders will be greater than such amounts would have been had the Fund of Funds invested directly in the securities held by the underlying funds, rather than investing in shares of the underlying funds. For similar reasons, the character of distributions from a Fund of Funds (e.g., long-term capital gain, exempt interest, eligibility for dividends-received deduction) will not necessarily be the same as it would have been had the Fund of Funds invested directly in the securities held by the underlying funds.

Depending on the percentage ownership of a Fund of Funds in an underlying fund before and after a redemption of underlying fund shares, the redemption of shares by the Fund of Funds of such underlying fund may cause the Fund of Funds to be treated as receiving a dividend in the full amount of the redemption proceeds instead of receiving a capital gain or loss on the redemption of shares of the underlying fund. This could be the case where a Fund of Funds holds a significant interest in an underlying fund that is not “publicly offered” (as defined in the Code) and redeems only a small portion of such interest. Dividend treatment of a redemption by a Fund of Funds would affect the amount and character of income required to be distributed by both the Fund of Funds and the underlying fund for the year in which the redemption occurred. It is possible that such a dividend would qualify as “qualified dividend income;” otherwise, it would be taxable as ordinary income and could cause shareholders of a Fund of Funds to recognize higher amounts of ordinary income than if the shareholders had held shares of the underlying fund directly.

If a Fund of Funds receives dividends from an underlying fund, and the underlying fund reports such dividends as “qualified dividend income,” as discussed below, then the Fund of Funds is permitted, in turn, to report a portion of its distributions as “qualified dividend income,” provided the Fund of Funds meets the holding period and other requirements with respect to shares of the underlying fund. If a Fund of Funds receives dividends from an underlying fund, and the underlying fund reports such dividends as eligible for the dividends-received deduction, then the Fund of Funds is permitted, in turn, to report a portion of its distributions as eligible

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for the dividends-received deduction, provided the Fund of Funds meets the holding period and other requirements with respect to shares of the underlying fund.

If a Fund of Funds is a “qualified fund of funds” (a regulated investment company that invests at least 50% of its total assets in other regulated investment companies at the close of each quarter of its taxable year), it will be able to distribute exempt-interest dividends and thereby pass through to its shareholders the tax-exempt character of any interest received on tax exempt obligations in which it directly invests or any exempt-interest dividends it receives from underlying funds in which it invests.

Further, if a Fund of Funds is a qualified fund of funds, it will be able to elect to pass through to its shareholders any foreign income and other similar taxes paid by the Fund of Funds or paid by an underlying fund in which the Fund of Funds invests that itself elected to pass such taxes through to shareholders, so that shareholders of the Fund of Funds will be eligible to claim a tax credit or deduction for such taxes. However, even if a Fund of Funds qualifies to make the election for any year, it may determine not to do so. For further considerations pertaining to foreign taxes paid by a Fund, see Foreign Taxes above.

Finally, a Fund-of-Funds generally must look through its 20 percent voting interest in a corporation, including an underlying fund, to the underlying assets thereof for purposes of the diversification test; special rules potentially provide limited relief from the application of this rule where the Fund-of-Funds is a “qualified fund-of-funds.”

Backup Withholding

Each Fund generally is required to withhold, and remit to the U.S. Treasury, subject to certain exemptions, a percentage of all distributions and redemption proceeds (including proceeds from exchanges and redemptions in-kind) paid or credited to a Fund shareholder if (1) the shareholder fails to furnish the Fund with a correct “taxpayer identification number” (TIN) or has not certified to the Fund that withholding does not apply or (2) the IRS notifies the Fund that the shareholder’s TIN is incorrect or the shareholder is otherwise subject to backup withholding. These backup withholding rules may also apply to distributions that are properly reported as exempt-interest dividends (defined above). This backup withholding is not an additional tax imposed on the shareholder. The shareholder may apply amounts required to be withheld as a credit against his or her future U.S. federal income tax liability, provided that the required information is furnished to the IRS. If a shareholder fails to furnish a valid TIN upon request, the shareholder can also be subject to IRS penalties.

Tax-Deferred Plans

The shares of a Fund may be available for a variety of tax-deferred retirement and other tax-advantaged plans and accounts. Prospective investors should contact their tax advisors and financial planners regarding the tax consequences to them of holding Fund shares through such plans and/or accounts.

Corporate Shareholders

Subject to limitations and other rules, a corporate shareholder of a Fund may be eligible for the dividends-received deduction on Fund distributions attributable to dividends received by the Fund from domestic corporations, which, if received directly by the corporate shareholder would qualify for such a deduction. For eligible corporate shareholders, the dividends-received deduction may be subject to certain reductions, and a distribution by a Fund attributable to dividends of a domestic corporation will be eligible for the deduction only if certain holding period and other requirements are met. For information regarding eligibility for the dividends-received deduction of dividend income derived by an underlying fund in which a Fund of Funds invests, see Special Tax Considerations Pertaining to Funds of Funds above. These requirements are complex; therefore, corporate shareholders of the Funds are urged to consult their own tax advisors and financial planners.

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As discussed above, a portion of the interest paid or accrued on certain high-yield discount obligations that a Fund may own may not be deductible to the issuer. If a portion of the interest paid or accrued on these obligations is not deductible, that portion will be treated as a dividend. In such cases, if the issuer of the obligation is a domestic corporation, dividend payments by a Fund may be eligible for the dividends-received deduction to the extent of the dividend portion of such interest.

Foreign Shareholders

For purposes of this discussion, “foreign shareholders” generally include: (i) nonresident alien individuals, (ii) foreign trusts (i.e., a trust other than a trust with respect to which a U.S. court is able to exercise primary supervision over administration of that trust and one or more U.S. persons have authority to control substantial decisions of that trust), (iii) foreign estates (i.e., the income of which is not subject to U.S. tax regardless of source) and (iv) foreign corporations.

Distributions by a Fund made to foreign shareholders that are not “U.S. persons” within the meaning of the Code properly reported by a Fund as (i) Capital Gain Dividends, (ii) short-term capital gain dividends, (iii) interest-related dividends or (iv) exempt-interest dividends, each as defined above or below, generally are not subject to withholding of U.S. federal income tax. In general, the Code defines (i) “short-term capital gain dividends” as distributions of net short-term capital gains in excess of net long-term capital losses and (ii) “interest-related dividends” as distributions from U.S. source interest income of types similar to those not subject to U.S. federal income tax if earned directly by an individual foreign shareholder, in each case to the extent such distributions are properly reported as such by the Fund in a written notice to shareholders. The exceptions to withholding for Capital Gain Dividends and short-term capital gain dividends do not apply to (a) distributions to an individual foreign shareholder who is present in the United States for a period or periods aggregating 183 days or more during the year of the distribution and (b) distributions attributable to gain that is treated as effectively connected with the conduct by the foreign shareholder of a trade or business within the United States under special rules regarding the disposition of U.S. real property interests as described below. The exception to withholding for interest-related dividends does not apply to distributions to a foreign shareholder (a) that has not provided a satisfactory statement that the beneficial owner is not a U.S. person, (b) to the extent that the dividend is attributable to certain interest on an obligation if the foreign shareholder is the issuer or is a 10% shareholder of the issuer, (c) that is within certain foreign countries that have inadequate information exchange with the United States, or (d) to the extent the dividend is attributable to interest paid by a person that is a related person of the foreign shareholder and the foreign shareholder is a controlled foreign corporation.

If a Fund invests in a RIC that pays Capital Gain Dividends, short-term capital gain dividends, exempt-interest dividends, or interest-related dividends to the Fund, such distributions retain their character as not subject to withholding if properly reported when paid by the Fund to foreign shareholders (provided, in the case of exempt-interest dividends, that the Fund and the underlying RIC meet the requirements discussed in Special Tax Considerations Pertaining to Funds-of-Funds above).

A Fund is permitted to report such part of its dividends as interest-related and/or short-term capital gain dividends as are eligible, but is not required to do so. In the case of shares held through an intermediary, the intermediary may withhold even if a Fund reports all or a portion of a payment as a short-term capital gain or interest-related dividend. Foreign shareholders should contact their intermediaries regarding the application of these rules to their accounts.

Distributions by a Fund to foreign shareholders other than Capital Gain Dividends, short-term capital gain dividends, exempt-interest dividends, and interest-related dividends (e.g., dividends attributable to foreign-source dividend and interest income, or to short-term capital gains or U.S. source interest income to which the exception from withholding description above does not apply) are generally subject to U.S. federal income tax withheld at a rate of 30% (or lower applicable treaty rate).

In general, a foreign shareholder’s capital gains realized on the disposition of Fund shares and distributions properly reported as Capital Gain Dividends are not subject to U.S. federal income or withholding tax unless:

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(i) such gains or distributions are effectively connected with a U.S. trade or business (or, if an income tax treaty applies, are attributable to a U.S. permanent establishment) of the foreign shareholder; (ii) in the case of an individual foreign shareholder, the shareholder is present in the U.S. for a period or periods aggregating 183 days or more during the year of the disposition of Fund shares or the receipt of Capital Gain Dividends and certain other conditions are met; or (iii) the special rules relating to gain attributable to the sale or exchange of “U.S. real property interests” (USRPIs) apply to the foreign shareholder’s sale of shares of the Fund (as described below).

Special rules apply if a Fund were a qualified investment entity (QIE) because it is either a “U.S. real property holding corporation” (USRPHC) or would be a USRPHC but for the operation of certain exceptions to the definition of USRPIs described below. Generally, a USRPHC is a domestic corporation that holds USRPIs the fair market value of which equals or exceeds 50% of the sum of the fair market values of the corporation’s USRPIs, interests in real property located outside the United States and other trade or business assets. USRPIs are generally defined as any interest in U.S. real property and any interest (other than solely as a creditor) in a USRPHC or, very generally, an entity that has been a USRPHC in the last five years. A Fund that holds, directly or indirectly, significant interests in REITs, may be a USRPHC. Interests in: (i) domestically controlled QIEs, including REITs and RICs that are QIEs, (ii) not-greater-than 10% interests in publicly traded classes of stock in REITs, and (iii) not-greater-than-5% interests in publicly traded classes of stock in RICs, generally are not USRPIs, but these exceptions do not apply for purposes of determining whether a Fund is a QIE. If an interest in a Fund were a USRPI, the Fund would be required to withhold U.S. tax on the proceeds of a share redemption by a greater-than-5% foreign shareholder, in which case such foreign shareholder generally would also be required to file U.S. tax returns and pay any additional taxes due in connection with the redemption. Moreover, if a Fund were a USRPHC or, very generally, had been one in the last five years, it would be required to withhold on amounts distributed to a greater-than-5% foreign shareholder to the extent such amounts would not be treated as a dividend, i.e., are in excess of the Fund’s current and accumulated “earnings and profits” for the applicable tax year. Such withholding generally is not required if the Fund is a domestically controlled QIE. If a Fund is a QIE, under a special “look through” rule, any distributions by the Fund to a greater-than-5% foreign shareholder (including, in certain cases, distributions made by the Fund in redemption of its shares) that are attributable directly or indirectly to (i) distributions received by the Fund from a lower-tier RIC or REIT that the Fund is required to treat as USRPI gain in its hands and (ii) gains realized on the disposition of USRPIs by the Fund will retain their character as gains realized from USRPIs in the hands of the Fund’s foreign shareholders and will be subject to U.S. tax withholding. In addition, such distributions could result in the foreign shareholder being required to file a U.S. income tax return and pay tax on the distributions at regular U.S. federal income tax rates. The consequences to a foreign shareholder, including the rate of such withholding and character of such distributions (e.g., as ordinary income or USRPI gain), would vary depending upon the extent of the foreign shareholder’s current and past ownership of a Fund. For purposes of this “look through” rule, beginning with the 2021 taxable year, the Fund is required to report Fund distributions attributable to USRPI from the Fund’s investments in REITs on forms 1099-DIV.

Foreign shareholders with respect to whom income from a Fund is effectively connected with a trade or business conducted by the foreign shareholder within the United States will in general be subject to U.S. federal income tax on the income derived from the Fund at the graduated rates applicable to U.S. citizens, residents or domestic corporations, whether such income is received in cash or reinvested in shares of a Fund and, in the case of a foreign corporation, may also be subject to a branch profits tax. If a foreign shareholder is eligible for the benefits of a tax treaty, any effectively connected income or gain will generally be subject to U.S. federal income tax on a net basis only if it is also attributable to a permanent establishment maintained by the shareholder in the United States. More generally, foreign shareholders who are residents in a country with an income tax treaty with the United States may obtain different tax results than those described herein, and are urged to consult their tax advisors. In order to qualify for any exemptions from withholding described above or for lower withholding tax rates under income tax treaties, or to establish an exemption from backup withholding, a foreign shareholder must comply with applicable certification requirements relating to its foreign status (including, in general, furnishing an IRS Form W-8BEN,W-8BEN-E or substitute form). Foreign shareholders should consult their tax advisors in this regard.

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Special rules (including withholding and reporting requirements) apply to foreign partnerships and those holding Fund shares through foreign partnerships. In addition, additional considerations may apply to foreign trusts and foreign estates. Investors holding Fund shares through foreign entities should consult their tax advisors about their particular situation.

A beneficial holder of shares who is a foreign person may be subject to state and local tax and to the U.S. federal estate tax in addition to the U.S. federal income tax referred to above.

Tax-Exempt Shareholders

Each Fund serves to “block” (that is, prevent the attribution to shareholders of) UBTI from being realized by tax-exempt shareholders. Notwithstanding this “blocking” effect, a tax-exempt shareholder could realize UBTI by virtue of its investment in a Fund if shares in the Fund constitute debt-financed property in the hands of the tax-exempt shareholder within the meaning of Code Section 514(b). For tax years beginning after 2017, entities subject to UBTI are required to calculate UBTI separately for each unrelated trade or business, which may limit their ability to offset gains and losses from multiple unrelated trades or businesses.

It is possible that a tax-exempt shareholder will also recognize UBTI if a Fund recognizes excess inclusion income (as described above) derived from direct or indirect investments in residual interests in real estate mortgage investment conduits (“REMICs”) or equity interests in taxable mortgage pools (“TMPs”). Furthermore, any investment in residual interests of a collateralized mortgage obligation (“CMO”) that has elected to be treated as a real estate mortgage investment conduit (REMIC) can create complex tax consequences, especially if the Fund has state or local governments or other tax-exempt organizations as shareholders.

In addition, special tax consequences apply to charitable remainder trusts (“CRTs”) that invest in regulated investment companies that invest directly or indirectly in residual interests in REMICs or equity interests in TMPs. A CRT, as defined in Section 664 of the Code, that realizes UBTI for a taxable year must pay an excise tax annually of an amount equal to such UBTI. Under IRS guidance issued in October 2006, a CRT will not recognize UBTI solely as a result of investing in a Fund to the extent that it recognizes excess inclusion income. Rather, if at any time during any taxable year a CRT (or one of certain other tax-exempt shareholders, such as the United States, a state or political subdivision, or an agency or instrumentality thereof, and certain energy cooperatives) is a record holder of a share in a Fund and the Fund recognizes excess inclusion income, then the Fund will be subject to a tax on that portion of its excess inclusion income for the taxable year that is allocable to such shareholders at the highest U.S. federal corporate income tax rate. The extent to which the IRS guidance remains applicable in light of the December 2006 legislation is unclear. To the extent permitted under the 1940 Act, each Fund may elect to specially allocate any such tax to the applicable CRT, or other shareholder, and thus reduce such shareholder’s distributions for the year by the amount of the tax that relates to such shareholder’s interest in the Fund. Each Fund has not yet determined whether such an election will be made. CRTs are urged to consult their tax advisors concerning the consequences of investing in a Fund.

Tax Shelter Reporting Regulations

Under U.S. Treasury Regulations, if a shareholder recognizes a loss of $2 million or more for an individual shareholder or $10 million or more for a corporate shareholder, the shareholder must file with the IRS a disclosure statement on IRS Form 8886. Direct holders of portfolio securities are in many cases excepted from this reporting requirement, but under current guidance, shareholders of a regulated investment company are not excepted. Future guidance may extend the current exception from this reporting requirement to shareholders of most or all regulated investment companies. The fact that a loss is reportable under these regulations does not affect the legal determination of whether the taxpayer’s treatment of the loss is proper. Shareholders should consult with their tax advisors to determine the applicability of these regulations in light of their individual circumstances.

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Shareholder Reporting Obligations With Respect to Foreign Bank and Financial Accounts

Shareholders that are U.S. persons and own, directly or indirectly, more than 50% of a Fund could be required to report annually their “financial interest” in the Fund’s “foreign financial accounts,” if any, on FinCEN Form 114, Report of Foreign Bank and Financial Accounts (FBAR). Shareholders should consult a tax advisor, and persons investing in the Fund through an intermediary should contact their intermediary, regarding the applicability to them of this reporting requirement.

Other Reporting and Withholding Requirements

Sections 1471-1474 of the Code, and the U.S. Treasury Regulations and IRS guidance issued thereunder (collectively, FATCA), generally require a Fund to obtain information sufficient to identify the status of each of its shareholders under FATCA or under an applicable intergovernmental agreement (an IGA) between the United States and a foreign government, as described more fully below. If a shareholder of a Fund fails to provide the requested information or otherwise fails to comply with FATCA or an IGA, the Fund is generally required to withhold under FATCA at a rate of 30% with respect to that shareholder on ordinary dividends it pays. The IRS and the Department of Treasury have issued proposed regulations providing that these withholding rules will not apply to the gross proceeds of share redemptions or Capital Gain Dividends the Fund pays. If a payment by a Fund is subject to FATCA withholding, the Fund is required to withhold even if such payment would otherwise be exempt from withholding under the rules applicable to foreign shareholders described above (e.g., exempt-interest dividends, short-term capital gain dividends and interest-related dividends).

Payments to a shareholder will generally not be subject to FATCA withholding, provided the shareholder provides a Fund with such certifications, waivers or other documentation or information as the Fund requires, including, to the extent required, with regard to such shareholder’s direct and indirect owners, to establish the shareholder’s FATCA status and otherwise to comply with these rules. In order to avoid withholding, a shareholder that is a “foreign financial institution” (FFI) must either (i) become a “participating FFI” by entering into a valid U.S. tax compliance agreement with the IRS, (ii) qualify for an exception from the requirement to enter into such an agreement, for example by becoming a “deemed-compliant FFI,” or (iii) be covered by an applicable intergovernmental agreement between the United States and a non-U.S. government to implement FATCA and improve international tax compliance. In any of these cases, the investing FFI generally will be required to provide its Fund with appropriate identifiers, certifications or documentation concerning its status.

A Fund may disclose the information that it receives from (or concerning) its shareholders to the IRS, non-U.S. taxing authorities or other parties as necessary to comply with FATCA, related intergovernmental agreements or other applicable law or regulation.

Each prospective investor is urged to consult its tax adviser regarding the applicability of FATCA and any other reporting requirements with respect to the prospective investor’s own situation, including investments through an intermediary.

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CONTROL PERSONS AND PRINCIPAL SHAREHOLDERS

Management Ownership of the Funds as of April 1, 2022

As of April 1, 2022, the Trustees and the officers of the Trust, as a group, owned less than 1% of the outstanding equity securities of each Fund, except that the Trustees and officers of the Trust together beneficially owned approximately 1% of the outstanding shares of Columbia Acorn European Fund.

Principal Holder and Control Person Ownership as of March 31, 2022

As of March 31, 2022, the name, address and percentage of ownership of each person, including certain Trustees and certain officers of Trust, who may be deemed to be a “principal holder” of a Fund as that term is defined in the 1940 Act (i.e., owns of record or is known by the Trust to own beneficially 5% or more of any class of a Fund’s outstanding shares) or a “control person” of a Fund as that term is defined in the 1940 Act (i.e., owns of record or is known by the Trust to own greater than 25% of a Fund’s outstanding shares, either beneficially or by virtue of its fiduciary or trust roles or otherwise), is shown below. A controlling person’s vote could have a more significant effect on matters presented to shareholders for approval than the vote of other shareholders.

Fund	Shareholder Name and Address	Share Class	Percentage of Class			Percentage of Fund (if greater than 25%)
Columbia Acorn European Fund	AMERICAN ENTERPRISE INVESTMENT SVC FBO 707 2ND AVE S MINNEAPOLIS MN 55402-2405	Class A		28.13	%	N/A
		Class C		42.96	%
		Class Inst		30.46	%
	ASCENSUS TRUST COMPANY FBO PO BOX 10758 FARGO ND 58106-0758	Class Inst3		7.39	%	N/A
	CHARLES SCHWAB & CO INC SPECIAL CUSTODY A/C FBO CUSTOMERS ATTN MUTUAL FUND DEPT 101 MONTGOMERY ST SAN FRANCISCO CA 94104-4151	Class A		23.08	%	N/A
	COLUMBIA MGMT INVESTMENT ADVSR LLC ATTN KATRINA MACBAIN 50807 AMERIPRISE FINANCIAL CTR MINNEAPOLIS MN 55474-0508	Class Inst3		8.53	%	N/A
	LPL FINANCIAL 9785 TOWNE CENTRE DR SAN DIEGO CA 92121-1968	Class A		5.29	%	N/A
		Class C		7.31	%
		Class Inst		5.18	%

186

Fund	Shareholder Name and Address	Share Class	Percentage of Class			Percentage of Fund (if greater than 25%)
	MORGAN STANLEY SMITH BARNEY LLC FOR THE EXCLUSIVE BENE OF ITS CUST 1 NEW YORK PLZ FL 12 NEW YORK NY 10004-1932	Class C		15.33	%		N/A
		Class Inst		11.74	%
	NATIONAL FINANCIAL SERVICES LLC FEBO CUSTOMERS MUTUAL FUNDS 200 LIBERTY STREET 1WFC NEW YORK NY 10281-1015	Class A		20.04	%		26.01	%
		Class Adv		62.39	%
		Class Inst2		89.32	%
	PERSHING LLC 1 PERSHING PLZ JERSEY CITY NJ 07399-0002	Class A		6.09	%		N/A
		Class Adv		32.70	%
		Class Inst3		84.08	%
	RAYMOND JAMES FBO OMNIBUS FOR MUTUAL FUNDS ATTN: COURTNEY WALLER 880 CARILLON PKWY ST PETERSBURG FL 33716-1100	Class C		8.17	%		N/A
		Class Inst		25.17	%
	RBC CAPITAL MARKETS, LLC MUTUAL FUND OMNIBUS PROCESSING OMNIBUS ATTN MUTUAL FUND OPS MANAGER 510 MARQUETTE AVE S MINNEAPOLIS MN 55402-1110	Class C		6.96	%		N/A
		Class Inst		8.37	%
	STIFEL NICOLAUS & CO INC EXCLUSIVE BENEFIT OF CUSTOMERS 501 N BROADWAY SAINT LOUIS MO 63102-2188	Class C		6.65	%		N/A
	TD AMERITRADE INC FBO OUR CUSTOMERS PO BOX 2226 OMAHA NE 68103-2226	Class A		9.11	%		N/A

187

Fund	Shareholder Name and Address	Share Class	Percentage of Class			Percentage of Fund (if greater than 25%)
	UBS WM USA SPEC CDY A/C EXCL BEN CUST UBSFSI 1000 HARBOR BLVD WEEHAWKEN NJ 07086-6761	Class Inst		7.27	%		N/A
Columbia Acorn Fund	AMERICAN ENTERPRISE INVESTMENT SVC FBO 707 2ND AVE S MINNEAPOLIS MN 55402-2405	Class A		11.79	%		N/A
		Class C		9.85	%
	ASCENSUS TRUST COMPANY FBO PO BOX 10758 FARGO ND 58106-0758	Class Inst3		9.18	%		N/A
	C/O ICMA RETIREMENT CORPORATION LA COUNTY SANITATION DISTRICT 457 777 N CAPITOL ST NE WASHINGTON DC 20002-4239	Class Adv		23.32	%		N/A
	CHARLES SCHWAB & CO INC SPECIAL CUSTODY A/C FBO CUSTOMERS ATTN MUTUAL FUND DEPT 101 MONTGOMERY ST SAN FRANCISCO CA 94104-4151	Class Inst		6.49	%		N/A
		Class Inst2		16.91	%
	DCGT AS TTEE AND/OR CUST FBO PLIC VARIOUS RETIREMENT PLANS OMNIBUS ATTN NPIO TRADE DESK 711 HIGH ST DES MOINES IA 50392-0001	Class Adv		16.82	%		N/A
	EDWARD D JONES & CO FOR THE BENEFIT OF CUSTOMERS 12555 MANCHESTER RD SAINT LOUIS MO 63131-3710	Class Inst3		24.92	%		N/A
	FIIOC FBO CRAFT MACHINE WORKS EMPLOYEE RETIREMENT & SAVINGS PLAN 100 MAGELLAN WAY # KW1C COVINGTON KY 41015-1987	Class Inst2		11.28	%		N/A

188

Fund	Shareholder Name and Address	Share Class	Percentage of Class			Percentage of Fund (if greater than 25%)
	GREAT-WEST TRUST COMPANY LLC FBO EMPLOYEE BENEFITS CLIENTS 401K 8515 E ORCHARD RD 2T2 GREENWOOD VILLAGE CO 80111-5002	Class Inst3		5.35	%		N/A
	JPMCB NA CUST FOR COLUMBIA THERMOSTAT FUND 4 CHASE METROTECH CTR FL 3RD BROOKLYN NY 11245-0003	Class Inst3		29.41	%		N/A
	LOCAL & COMPANY NOMINEE FOR TRUST COMPANY OF TOLEDO TRUSTEE TOLEDO SYMPHONY ORCHESTRA RETIREMENT SAVINGS PLAN 1630 TIMBER WOLF DR HOLLAND OH 43528-8303	Class Inst2		12.74	%		N/A
	LPL FINANCIAL 9785 TOWNE CENTRE DR SAN DIEGO CA 92121-1968	Class A		7.99	%		N/A
		Class C		24.85	%
	MERRILL LYNCH PIERCE FENNER & SMITH FBO LOUIS SENNELLO TTEE LOUIS SENNELLO TRUST 4800 DEER LAKE DR E FL 2 JACKSONVILLE FL 32246-6484	Class A		8.97	%		N/A
		Class Adv		14.90	%
	MORGAN STANLEY SMITH BARNEY LLC FOR THE EXCLUSIVE BENE OF ITS CUST 1 NEW YORK PLZ FL 12 NEW YORK NY 10004-1932	Class A		5.16	%		N/A
	NATIONAL FINANCIAL SERVICES LLC FEBO CUSTOMERS MUTUAL FUNDS 200 LIBERTY STREET 1WFC NEW YORK NY 10281-1015	Class A		10.52	%		N/A
		Class Adv		11.48	%
		Class Inst		7.99	%
		Class Inst2		22.12	%
		Class Inst3		6.44	%

189

Fund	Shareholder Name and Address	Share Class	Percentage of Class			Percentage of Fund (if greater than 25%)
	PERSHING LLC 1 PERSHING PLZ JERSEY CITY NJ 07399-0002	Class A		8.52	%		N/A
		Class Adv		17.08	%
		Class C		12.26	%
		Class Inst2		11.93	%
	RAYMOND JAMES FBO OMNIBUS FOR MUTUAL FUNDS ATTN: COURTNEY WALLER 880 CARILLON PKWY ST PETERSBURG FL 33716-1100	Class C		5.24	%		N/A
	TD AMERITRADE INC FBO OUR CUSTOMERS PO BOX 2226 OMAHA NE 68103-2226	Class Inst2		12.72	%		N/A
	VANGUARD FDUCIARY TRUST CO PO BOX 2600 VM 613 ATTN: OUTSIDE FUNDS VALLEY FORGE PA 19482-2600	Class Inst3		8.82	%		N/A
	WELLS FARGO CLEARING SERVICES LLC SPECIAL CUSTODY ACCT FOR THE EXCLUSIVE BENEFIT OF CUSTOMER 2801 MARKET ST SAINT LOUIS MO 63103-2523	Class A		7.66	%		N/A
		Class C		11.07	%
Columbia Acorn International	AMERICAN ENTERPRISE INVESTMENT SVC FBO 707 2ND AVE S MINNEAPOLIS MN 55402-2405	Class A		43.38	%		N/A
		Class C		32.44	%
	ASCENSUS TRUST COMPANY FBO PO BOX 10758 FARGO ND 58106-0758	Class C		7.79	%		N/A
		Class R		11.31	%
	BOWER FOUNDATION 578 HIGHLAND COLONY PKWY STE 120 RIDGELAND MS 39157-8779	Class Inst3		8.02	%		N/A

190

Fund	Shareholder Name and Address	Share Class	Percentage of Class			Percentage of Fund (if greater than 25%)
	C/O TOMPKINS TRUST COMPANY SEI PRIVATE TRUST COMPANY 1 FREEDOM VALLEY DR OAKS PA 19456-9989	Class Inst		6.76	%		N/A
		Class Inst2		53.75	%
	CHARLES SCHWAB & CO INC SPECIAL CUSTODY A/C FBO CUSTOMERS ATTN MUTUAL FUND DEPT 101 MONTGOMERY ST SAN FRANCISCO CA 94104-4151	Class Adv		7.34	%		N/A
		Class Inst		8.38	%
		Class Inst2		16.86	%
	EDWARD D JONES & CO FOR THE BENEFIT OF CUSTOMERS 12555 MANCHESTER RD SAINT LOUIS MO 63131-3710	Class Inst3		48.11	%		N/A
	LPL FINANCIAL 9785 TOWNE CENTRE DR SAN DIEGO CA 92121-1968	Class C		15.62	%		N/A
	MATRIX TRUST COMPANY AS AGENT FOR ADVISOR TRUST, INC WHARTON COUNTY JR COLLEGE (TX) 403B 717 17TH ST STE 1300 DENVER CO 80202-3304	Class R		21.74	%		N/A
	MERRILL LYNCH PIERCE FENNER & SMITH FBO LOUIS SENNELLO TTEE LOUIS SENNELLO TRUST 4800 DEER LAKE DR E FL 2 JACKSONVILLE FL 32246-6484	Class Inst		5.83	%		N/A
	MG TRUST COMPANY CUST. FBO 717 17TH ST STE 1300 DENVER CO 80202-3304	Class R		9.93	%		N/A
	MID ATLANTIC TRUST COMPANY FBO 1251 WATERFRONT PL STE 525 PITTSBURGH PA 15222-4228	Class R		20.00	%		N/A

191

Fund	Shareholder Name and Address	Share Class	Percentage of Class			Percentage of Fund (if greater than 25%)
	NATIONAL FINANCIAL SERVICES LLC FEBO CUSTOMERS MUTUAL FUNDS 200 LIBERTY STREET 1WFC NEW YORK NY 10281-1015	Class A		6.00	%		N/A
		Class Adv		52.64	%
		Class Inst		9.38	%
		Class Inst2		15.40	%
		Class Inst3		32.86	%
		Class R		5.22	%
	PERSHING LLC 1 PERSHING PLZ JERSEY CITY NJ 07399-0002	Class Adv		21.14	%		N/A
	STATE STREET CORPORATION FBO ADP ACCESS 1 LINCOLN ST BOSTON MA 02111-2901	Class R		25.57	%		N/A
	UBS WM USA SPEC CDY A/C EXCL BEN CUST UBSFSI 1000 HARBOR BLVD WEEHAWKEN NJ 07086-6761	Class C		6.29	%		N/A
Columbia Acorn International Select	AMERICAN ENTERPRISE INVESTMENT SVC FBO 707 2ND AVE S MINNEAPOLIS MN 55402-2405	Class A		42.19	%		25.08	%
		Class C		26.82	%
		Class Inst		10.39	%
	ASCENSUS TRUST COMPANY FBO PO BOX 10758 FARGO ND 58106-0758	Class C		28.72	%		N/A
	BNY MELLON CUST FBO EVERSOURCE NON UNION MEDICAL TRUST 107 SELDEN ST BERLIN CT 06037-1616	Class Inst3		20.41	%		N/A
	CHARLES SCHWAB & CO INC SPECIAL CUSTODY A/C FBO CUSTOMERS ATTN MUTUAL FUND DEPT 101 MONTGOMERY ST SAN FRANCISCO CA 94104-4151	Class A		6.37	%		N/A
		Class Adv		9.90	%
		Class Inst		8.77	%
		Class Inst2		89.92	%

192

Fund	Shareholder Name and Address	Share Class	Percentage of Class			Percentage of Fund (if greater than 25%)
	EDWARD D JONES & CO FOR THE BENEFIT OF CUSTOMERS 12555 MANCHESTER RD SAINT LOUIS MO 63131-3710	Class Inst3		52.74	%		N/A
	LPL FINANCIAL 9785 TOWNE CENTRE DR SAN DIEGO CA 92121-1968	Class Adv		14.94	%		N/A
	MERRILL LYNCH PIERCE FENNER & SMITH FBO LOUIS SENNELLO TTEE LOUIS SENNELLO TRUST 4800 DEER LAKE DR E FL 2 JACKSONVILLE FL 32246-6484	Class A		6.70	%		N/A
		Class Inst		7.19	%
	NATIONAL FINANCIAL SERVICES LLC FEBO CUSTOMERS MUTUAL FUNDS 200 LIBERTY STREET 1WFC NEW YORK NY 10281-1015	Class A		5.26	%		N/A
		Class Adv		33.95	%
		Class Inst		5.96	%
		Class Inst3		15.00	%
	PERSHING LLC 1 PERSHING PLZ JERSEY CITY NJ 07399-0002	Class Adv		37.51	%		N/A
	RELIANCE TRUST COMPANY FBO MASSMUTUAL REGISTERED PRODUCT PO BOX 28004 ATLANTA GA 30358-0004	Class Inst3		7.95	%		N/A
	WELLS FARGO CLEARING SERVICES LLC SPECIAL CUSTODY ACCT FOR THE EXCLUSIVE BENEFIT OF CUSTOMER 2801 MARKET ST SAINT LOUIS MO 63103-2523	Class C		8.66	%		N/A
Columbia Acorn USA	AMERICAN ENTERPRISE INVESTMENT SVC FBO 707 2ND AVE S MINNEAPOLIS MN 55402-2405	Class A		15.47	%		N/A
		Class C		27.34	%

193

Fund	Shareholder Name and Address	Share Class	Percentage of Class			Percentage of Fund (if greater than 25%)
	ASCENSUS TRUST COMPANY FBO PO BOX 10758 FARGO ND 58106-0758	Class Inst2		5.48	%		N/A
	CHARLES SCHWAB & CO INC SPECIAL CUSTODY A/C FBO CUSTOMERS ATTN MUTUAL FUND DEPT 101 MONTGOMERY ST SAN FRANCISCO CA 94104-4151	Class Inst		7.73	%		N/A
		Class Inst2		8.51	%
	EDWARD D JONES & CO FOR THE BENEFIT OF CUSTOMERS 12555 MANCHESTER RD SAINT LOUIS MO 63131-3710	Class Inst3		5.48	%		N/A
	JOHN HANCOCK TRUST COMPANY LLC 690 CANTON ST STE 100 WESTWOOD MA 02090-2344	Class Adv		87.29	%		N/A
	LPL FINANCIAL 9785 TOWNE CENTRE DR SAN DIEGO CA 92121-1968	Class A		12.47	%		N/A
		Class C		11.76	%
	MATRIX TRUST COMPANY AS AGENT FOR NEWPORT TRUST COMPANY KROESE & KROESE 401(K) PLAN 35 IRON POINT CIR STE 300 FOLSOM CA 95630-8589	Class Inst2		8.94	%		N/A
	NATIONAL FINANCIAL SERVICES LLC FEBO CUSTOMERS MUTUAL FUNDS 200 LIBERTY STREET 1WFC NEW YORK NY 10281-1015	Class A		9.36	%		N/A
		Class Inst		5.64	%
		Class Inst2		63.90	%
		Class Inst3		48.18	%
	PERSHING LLC 1 PERSHING PLZ JERSEY CITY NJ 07399-0002	Class A		7.99	%		N/A
		Class C		16.04	%
		Class Inst2		9.26	%
	TD AMERITRADE INC FBO OUR CUSTOMERS PO BOX 2226 OMAHA NE 68103-2226	Class C		8.12	%		N/A

194

Fund	Shareholder Name and Address	Share Class	Percentage of Class			Percentage of Fund (if greater than 25%)
	THE TRUST COMPANY OF KNOXILLE 1 4823 OLD KINGSTON PIKE STE 100 KNOXVILLE TN 37919-6499	Class Inst3		40.77	%		N/A
	UMB BANK NA VARICHEM INT’L USA NDFI S-IRA 820 3RD ST BAY CITY TX 77414-5817	Class C		6.16	%		N/A
	WELLS FARGO CLEARING SERVICES LLC SPECIAL CUSTODY ACCT FOR THE EXCLUSIVE BENEFIT OF CUSTOMER 2801 MARKET ST SAINT LOUIS MO 63103-2523	Class C		6.02	%		N/A
Columbia Thermostat Fund	AMERICAN ENTERPRISE INVESTMENT SVC FBO 707 2ND AVE S MINNEAPOLIS MN 55402-2405	Class A		33.92	%		N/A
		Class C		25.55	%
		Class Inst		17.29	%
	CHARLES SCHWAB & CO INC SPECIAL CUSTODY A/C FBO CUSTOMERS ATTN MUTUAL FUND DEPT 101 MONTGOMERY ST SAN FRANCISCO CA 94104-4151	Class A		6.67	%		N/A
		Class Adv		7.05	%
		Class Inst2		23.69	%
	LPL FINANCIAL 9785 TOWNE CENTRE DR SAN DIEGO CA 92121-1968	Class C		9.42	%		N/A
		Class Inst		11.21	%
	MERRILL LYNCH PIERCE FENNER & SMITH FBO LOUIS SENNELLO TTEE LOUIS SENNELLO TRUST 4800 DEER LAKE DR E FL 2 JACKSONVILLE FL 32246-6484	Class A		6.55	%		N/A
		Class C		5.73	%
		Class Inst		16.09	%

195

Fund	Shareholder Name and Address	Share Class	Percentage of Class			Percentage of Fund (if greater than 25%)
	MG TRUST COMPANY CUST. FBO 717 17TH ST STE 1300 DENVER CO 80202-3304	Class Inst3		7.95	%		N/A
	MORGAN STANLEY SMITH BARNEY LLC FOR THE EXCLUSIVE BENE OF ITS CUST 1 NEW YORK PLZ FL 12 NEW YORK NY 10004-1932	Class A		5.15	%		N/A
		Class C		6.78	%
		Class Inst		15.69	%
	NATIONAL FINANCIAL SERVICES LLC FEBO CUSTOMERS MUTUAL FUNDS 200 LIBERTY STREET 1WFC NEW YORK NY 10281-1015	Class A		19.88	%		N/A
		Class Adv		43.74	%
		Class C		11.46	%
		Class Inst2		44.10	%
		Class Inst3		77.44	%
	PERSHING LLC 1 PERSHING PLZ JERSEY CITY NJ 07399-0002	Class Adv		47.26	%		N/A
		Class C		5.38	%
		Class Inst2		9.85	%
	RAYMOND JAMES FBO OMNIBUS FOR MUTUAL FUNDS ATTN: COURTNEY WALLER 880 CARILLON PKWY ST PETERSBURG FL 33716-1100	Class C		6.24	%		N/A
		Class Inst		12.98	%
	TD AMERITRADE INC FBO OUR CUSTOMERS PO BOX 2226 OMAHA NE 68103-2226	Class Inst2		19.29	%		N/A
	UBS WM USA SPEC CDY A/C EXCL BEN CUST UBSFSI 1000 HARBOR BLVD WEEHAWKEN NJ 07086-6761	Class Inst		5.65	%		N/A

196

Fund	Shareholder Name and Address	Share Class	Percentage of Class			Percentage of Fund (if greater than 25%)
	WELLS FARGO CLEARING SERVICES LLC SPECIAL CUSTODY ACCT FOR THE EXCLUSIVE BENEFIT OF CUSTOMER 2801 MARKET ST SAINT LOUIS MO 63103-2523	Class A		5.42	%		N/A
		Class C		17.32	%
		Class Inst		10.02	%

National Financial Services, LLC, a Delaware limited liability company, is wholly owned by Fidelity Global Brokerage Group, Inc., a wholly owned subsidiary of FMR LLC.

197

APPENDIX A — DESCRIPTIONS OF SECURITIES RATINGS

This Appendix A summarizes the various descriptions of securities ratings applicable to securities purchased by the Columbia Funds Complex. The ratings of S&P, Moody’s Fitch, DBRS, and KBRA represent their opinions as to quality. These ratings are not absolute standards of quality and are not recommendations to purchase, sell or hold a security. Issuers and issues are subject to risks that are not evaluated by the rating agencies. Please refer to a Fund’s prospectus and this SAI to determine whether the Fund may invest in securities that have ratings described in this Appendix A. When a security is not rated by one of these agencies, it is designated as Not Rated. Securities designated as Not Rated do not necessarily indicate low credit quality, and for such securities the Investment Manager or its affiliates evaluates the credit quality.

The following ratings descriptions, which were derived as of March 24, 2022 from the particular credit rating agency’s website, identify the date such descriptions were then last updated by such credit rating agency.

S&P’s RATINGS (last updated on November 10, 2021)

Long-Term Issue Credit Ratings*

An obligation rated ‘AAA’ has the highest rating assigned by S&P Global Ratings. The obligor’s capacity to meet its financial commitments on the obligation is extremely strong.

An obligation rated ‘AA’ differs from the highest-rated obligations only to a small degree. The obligor’s capacity to meet its financial commitments on the obligation is very strong.

An obligation rated ‘A’ is somewhat more susceptible to the adverse effects of changes in circumstances and economic conditions than obligations in higher-rated categories. However, the obligor’s capacity to meet its financial commitments on the obligation is still strong.

An obligation rated ‘BBB’ exhibits adequate protection parameters. However, adverse economic conditions or changing circumstances are more likely to weaken the obligor’s capacity to meet its financial commitments on the obligation.

Obligations rated ‘BB’, ‘B’, ‘CCC’, ‘CC’, and ‘C’ are regarded as having significant speculative characteristics. ‘BB’ indicates the least degree of speculation and ‘C’ the highest. While such obligations will likely have some quality and protective characteristics, these may be outweighed by large uncertainties or major exposure to adverse conditions.

An obligation rated ‘BB’ is less vulnerable to nonpayment than other speculative issues. However, it faces major ongoing uncertainties or exposure to adverse business, financial, or economic conditions that could lead to the obligor’s inadequate capacity to meet its financial commitment on the obligation.

An obligation rated ‘B’ is more vulnerable to nonpayment than obligations rated ‘BB’, but the obligor currently has the capacity to meet its financial commitments on the obligation. Adverse business, financial, or economic conditions will likely impair the obligor’s capacity or willingness to meet its financial commitment on the obligation.

An obligation rated ‘CCC’ is currently vulnerable to nonpayment, and is dependent upon favorable business, financial, and economic conditions for the obligor to meet its financial commitments on the obligation. In the event of adverse business, financial, or economic conditions, the obligor is not likely to have the capacity to meet its financial commitments on the obligation.

An ‘SP-2’ rating indicates satisfactory capacity to pay principal and interest, with some vulnerability to adverse financial and economic changes over the term of the notes.

A-1

An obligation rated ‘CC’ is currently highly vulnerable to nonpayment. The ‘CC’ rating is used when a default has not yet occurred, but S&P Global Ratings expects default to be a virtual certainty, regardless of the anticipated time to default.

An obligation rated ‘C’ is currently highly vulnerable to nonpayment, and the obligation is expected to have lower relative seniority or lower ultimate recovery compared with obligations that are rated higher.

An obligation rated ‘D’ is in default or in breach of an imputed promise. For non-hybrid capital instruments, the ‘D’ rating category is used when payments on an obligation are not made on the date due, unless S&P Global Ratings believes that such payments will be made within the next five business days in the absence of a stated grace period or within the earlier of the stated grace period or the next 30 calendar days. The ‘D’ rating also will be used upon the filing of a bankruptcy petition or the taking of similar action and where default on an obligation is a virtual certainty, for example due to automatic stay provisions. A rating on an obligation is lowered to ‘D’ if it is subject to a distressed debt restructuring.

* Ratings from ‘‘AA’’ to ‘‘CCC’’ may be modified by the addition of a plus (+) or minus (-) sign to show relative standing within the rating categories.

Short-Term Issue Credit Ratings

A short-term obligation rated ‘A-1’ is rated in the highest category by S&P Global Ratings. The obligor’s capacity to meet its financial commitments on the obligation is strong. Within this category, certain obligations are designated with a plus sign (+). This indicates that the obligor’s capacity to meet its financial commitments on these obligations is extremely strong.

A short-term obligation rated ‘A-2’ is somewhat more susceptible to the adverse effects of changes in circumstances and economic conditions than obligations in higher rating categories. However, the obligor’s capacity to meet its financial commitments on the obligation is satisfactory.

A short-term obligation rated ‘A-3’ exhibits adequate protection parameters. However, adverse economic conditions or changing circumstances are more likely weaken an obligor’s capacity to meet its financial commitments on the obligation.

A short-term obligation rated ‘B’ is regarded as vulnerable and has significant speculative characteristics. The obligor currently has the capacity to meet its financial commitments; however, it faces major ongoing uncertainties that could lead to the obligor’s inadequate capacity to meet its financial commitments.

A short-term obligation rated ‘C’ is currently vulnerable to nonpayment and is dependent upon favorable business, financial, and economic conditions for the obligor to meet its financial commitments on the obligation.

A short-term obligation rated ‘D’ is in default or in breach of an imputed promise. For non-hybrid capital instruments, the ‘D’ rating category is used when payments on an obligation are not made on the date due, unless S&P Global Ratings believes that such payments will be made within any stated grace period. However, any stated grace period longer than five business days will be treated as five business days. The ‘D’ rating also will be used upon the filing of a bankruptcy petition or the taking of a similar action and where default on an obligation is a virtual certainty, for example due to automatic stay provisions. A rating on an obligation is lowered to ‘D’ if it is subject to a distressed debt restructuring.

Municipal Short-Term Note Ratings

An ‘SP-1’ rating indicates strong capacity to pay principal and interest. An issue determined to possess a very strong capacity to pay debt service is given a plus (+) designation.

A-2

An ‘SP-3’ rating indicates speculative capacity to pay principal and interest.

A ‘D’ rating is assigned upon failure to pay the note when due, completion of a distressed debt restructuring, or the filing of a bankruptcy petition or the taking of similar action and where default on an obligation is a virtual certainty, for example due to automatic stay provisions.

MOODY’S RATINGS (last updated in March 22, 2022)

Global Long-Term Rating Scale

Aaa — Obligations rated Aaa are judged to be of the highest quality, subject to the lowest level of credit risk.

Aa — Obligations rated Aa are judged to be of high quality and are subject to very low credit risk.

A — Obligations rated A are judged to be upper-medium grade and are subject to low credit risk.

Baa — Obligations rated Baa are judged to be medium-grade and subject to moderate credit risk and as such may possess certain speculative characteristics.

Ba — Obligations rated Ba are judged to be speculative and are subject to substantial credit risk.

B — Obligations rated B are considered speculative and are subject to high credit risk.

Caa — Obligations rated Caa are judged to be speculative of poor standing and are subject to very high credit risk.

Ca — Obligations rated Ca are highly speculative and are likely in, or very near, default, with some prospect of recovery of principal and interest.

C — Obligations rated C are the lowest rated and are typically in default, with little prospect for recovery of principal or interest.

Note: Moody’s appends numerical modifiers 1, 2, and 3 to each generic rating classification from Aa through Caa. The modifier 1 indicates that the obligation ranks in the higher end of its generic rating category; the modifier 2 indicates a mid-range ranking; and the modifier 3 indicates a ranking in the lower end of that generic rating category. Additionally, a “(hyb)” indicator is appended to all ratings of hybrid securities issued by banks, insurers, finance companies, and securities firms.*

* By their terms, hybrid securities allow for the omission of scheduled dividends, interest, or principal payments, which can potentially result in impairment if such an omission occurs. Hybrid securities may also be subject to contractually allowable write-downs of principal that could result in impairment. Together with the hybrid indicator, the long-term obligation rating assigned to a hybrid security is an expression of the relative credit risk associated with that security.

Global Short-Term Rating Scale

P-1 — Ratings of Prime-1 reflect a superior ability to repay short-term obligations.

P-2 — Ratings of Prime-2 reflect a strong ability to repay short-term obligations.

P-3 — Ratings of Prime-3 reflect an acceptable ability to repay short-term obligations.

NP — Issuers (or supporting institutions) rated Not Prime do not fall within any of the Prime rating categories.

A-3

U.S. Municipal Short-Term Debt and Demand Obligation Ratings

Municipal Investment Grade (MIG) Scale

MIG 1 — This designation denotes superior credit quality. Excellent protection is afforded by established cash flows, highly reliable liquidity support, or demonstrated broad-based access to the market for refinancing.

MIG 2 — This designation denotes strong credit quality. Margins of protection are ample, although not as large as in the preceding group.

MIG 3 — This designation denotes acceptable credit quality. Liquidity and cash-flow protection may be narrow, and market access for refinancing is likely to be less well-established.

SG — This designation denotes speculative-grade credit quality. Debt instruments in this category may lack sufficient margins of protection.

VMIG 1 — This designation denotes superior credit quality. Excellent protection is afforded by the superior short-term credit strength of the liquidity provider and structural and legal protections.

VMIG 2 — This designation denotes strong credit quality. Good protection is afforded by the strong short-term credit strength of the liquidity provider and structural and legal protections.

VMIG 3 — This designation denotes acceptable credit quality. Adequate protection is afforded by the satisfactory short-term credit strength of the liquidity provider and structural and legal protections.

SG — This designation denotes speculative-grade credit quality. Demand features rated in this category may be supported by a liquidity provider that does not have a sufficiently strong short-term rating or may lack the structural or legal protections.

For variable rate demand obligations, Moody’s typically assigns the VMIG short-term demand obligation rating if the frequency of the demand feature is less than every three years. If the frequency of the demand feature is less than three years but the purchase price is payable only with remarketing proceeds, the short-term demand obligation rating is “NR”.

FITCH’S RATINGS (last updated on March 21, 2022)

Corporate Finance Obligations — Long-Term Rating Scales

AAA: Highest Credit Quality. ‘AAA’ ratings denote the lowest expectation of credit risk. They are assigned only in cases of exceptionally strong capacity for payment of financial commitments. This capacity is highly unlikely to be adversely affected by foreseeable events.

AA: Very High Credit Quality. ‘AA’ ratings denote expectations of very low credit risk. They indicate very strong capacity for payment of financial commitments. This capacity is not significantly vulnerable to foreseeable events.

A: High Credit Quality. ‘A’ ratings denote expectations of low credit risk. The capacity for payment of financial commitments is considered strong. This capacity may, nevertheless, be more vulnerable to adverse business or economic conditions than is the case for higher ratings.

A-4

BBB: Good Credit Quality. ‘BBB’ ratings indicate that expectations of credit risk are currently low. The capacity for payment of financial commitments is considered adequate but adverse business or economic conditions are more likely to impair this capacity.

BB: Speculative. ‘BB’ ratings indicate an elevated vulnerability to credit risk, particularly in the event of adverse changes in business or economic conditions over time; however, business or financial alternatives may be available to allow financial commitments to be met.

B: Highly Speculative. ‘B’ ratings indicate that material credit risk is present.

CCC: Substantial Credit Risk. ‘CCC’ ratings indicate that substantial credit risk is present.

CC: Very High Levels of Credit Risk. ‘CC’ ratings indicate very high levels of credit risk.

C: Exceptionally High Levels of Credit Risk. ‘C’ indicates exceptionally high levels of credit risk.

Ratings in the categories of ‘CCC’, ‘CC’ and ‘C’ can also relate to obligations or issuers that are in default. In this case, the rating does not opine on default risk but reflects the recovery expectation only.

Corporate finance defaulted obligations typically are not assigned ‘RD’ or ‘D’ ratings, but are instead rated in the ‘B’ to ‘C’ rating categories, depending on their recovery prospects and other relevant characteristics. This approach better aligns obligations that have comparable overall expected loss but varying vulnerability to default and loss.

Short-Term Ratings Assigned to Issuers and Obligations

F1: Highest Short-Term Credit Quality. Indicates the strongest intrinsic capacity for timely payment of financial commitments; may have an added “+” to denote any exceptionally strong credit feature.

F2: Good Short-Term Credit Quality. Good intrinsic capacity for timely payment of financial commitments.

F3: Fair Short-Term Credit Quality. The intrinsic capacity for timely payment of financial commitments is adequate.

B: Speculative Short-Term Credit Quality. Minimal capacity for timely payment of financial commitments, plus heightened vulnerability to near term adverse changes in financial and economic conditions.

C: High Short-Term Default Risk. Default is a real possibility.

RD: Restricted Default. Indicates an entity that has defaulted on one or more of its financial commitments, although it continues to meet other financial obligations. Typically applicable to entity ratings only.

D: Default. Indicates a broad-based default event for an entity, or the default of a short-term obligation.

A-5

The table below reflects typical relationships between the long-term rating and the short-term rating.

Long-Term Rating	Short-Term Rating
AAA	F1+
AA+	F1+
AA	F1+
AA-	F1+
A+	F1 or F1+
A	F1 or F1+
A-	F2 or F1
BBB+	F2 or F1
BBB	F3 or F2
BBB-	F3
BB+	B
BB	B
BB-	B
B+	B
B	B
B-	B
CCC+ / CCC / CCC–	C
CC	C
C	C
RD / D	RD / D

DBRS’ RATINGS (last updated in January 2022)

Long-Term Obligations Scale

All rating categories other than AAA and D also contain subcategories (high) and (low). The absence of either a (high) or (low) designation indicates that the rating is in the middle of the category.

AAA. Highest credit quality. The capacity for the payment of financial obligations is exceptionally high and unlikely to be adversely affected by future events.

AA. Superior credit quality. The capacity for the payment of financial obligations is considered high. Credit quality differs from AAA only to a small degree. Unlikely to be significantly vulnerable to future events.

A. Good credit quality. The capacity for the payment of financial obligations is substantial, but of lesser credit quality than AA. May be vulnerable to future events, but qualifying negative factors are considered manageable.

BBB. Adequate credit quality. The capacity for the payment of financial obligations is considered acceptable. May be vulnerable to future events.

BB. Speculative, non-investment-grade credit quality. The capacity for the payment of financial obligations is uncertain. Vulnerable to future events.

B. Highly speculative credit quality. There is a high level of uncertainty as to the capacity to meet financial obligations.

A-6

CCC / CC / C. Very highly speculative credit quality. In danger of defaulting on financial obligations. There is little difference between these three categories, although CC and C ratings are normally applied to obligations that are seen as highly likely to default or subordinated to obligations rated in the CCC to B range. Obligations in respect of which default has not technically taken place, but is considered inevitable, may be rated in the C category.

D. When the issuer has filed under any applicable bankruptcy, insolvency or winding-up statute or there is a failure to satisfy an obligation after the exhaustion of grace periods, a downgrade to D may occur. DBRS Morningstar may also use SD (Selective Default) in cases where only some 15 DBRS Morningstar Product Guide securities are impacted, such as the case of a distressed exchange. See the Default Definition document on dbrsmorningstar.com under Understanding Ratings for more information.

Commercial Paper and Short-Term Debt Rating Scale

The R-1 and R-2 rating categories are further denoted by the subcategories (high), (middle) and (low).

R-1 (high). Highest credit quality. The capacity for the payment of short-term financial obligations as they fall due is exceptionally high. Unlikely to be adversely affected by future events.

R-1 (middle). Superior credit quality. The capacity for the payment of short-term financial obligations as they fall due is very high. Differs from R-1 (high) by a relatively modest degree. Unlikely to be significantly vulnerable to future events.

R-1 (low). Good credit quality. The capacity for the payment of short-term financial obligations as they fall due is substantial. Overall strength is not as favorable as higher rating categories. May be vulnerable to future events, but qualifying negative factors are considered manageable.

R-2 (high). Upper end of adequate credit quality. The capacity for the payment of short-term financial obligations as they fall due is acceptable. May be vulnerable to future events.

R-2 (middle). Adequate credit quality. The capacity for the payment of short-term financial obligations as they fall due is acceptable. May be vulnerable to future events or may be exposed to other factors that could reduce credit quality.

R-2 (low). Lower end of adequate credit quality. The capacity for the payment of short-term financial obligations as they fall due is acceptable. May be vulnerable to future events. A number of challenges are present that could affect the issuer’s ability to meet such obligations.

R-3. Lowest end of adequate credit quality. There is capacity for the payment of short-term financial obligations as they fall due. May be vulnerable to future events and the certainty of meeting such obligations could be impacted by a variety of developments.

R-4. Speculative credit quality. The capacity for the payment of short-term financial obligations as they fall due is uncertain.

R-5. Highly speculative credit quality. There is a high level of uncertainty as to the capacity to meet short-term financial obligations as they fall due.

D. When the issuer has filed under any applicable bankruptcy, insolvency or winding-up statute or there is a failure to satisfy an obligation after the exhaustion of grace periods, a downgrade to D may occur. DBRS Morningstar may also use SD (Selective Default) in cases where only some 16 DBRS Morningstar Product Guide securities are impacted, such as the case of a distressed exchange. See the Default Definition document on dbrsmorningstar.com under Understanding Ratings for more information.

A-7

KBRA’s RATINGS (derived from the credit rating agency’s website as of March 24, 2022)

Long-Term Credit Rating Scale

AAA: Determined to have almost no risk of loss due to credit-related events. Assigned only to the very highest quality obligors and obligations able to survive extremely challenging economic events.

AA: Determined to have minimal risk of loss due to credit-related events. Such obligors and obligations are deemed very high quality.

A: Determined to be of high quality with a small risk of loss due to credit-related events. Issuers and obligations in this category are expected to weather difficult times with low credit losses.

BBB: Determined to be of medium quality with some risk of loss due to credit-related events. Such issuers and obligations may experience credit losses during stress environments.

BB: Determined to be of low quality with moderate risk of loss due to credit-related events. Such issuers and obligations have fundamental weaknesses that create moderate credit risk.

B: Determined to be of very low quality with high risk of loss due to credit-related events. These issuers and obligations contain many fundamental shortcomings that create significant credit risk.

CCC: Determined to be at substantial risk of loss due to credit-related events, near default, or in default with high recovery expectations.

CC: Determined to be near default or in default with average recovery expectations.

C: Determined to be near default or in default with low recovery expectations.

D: KBRA defines default as occurring if:

• There is a missed interest payment, principal payment, or preferred dividend payment, as applicable, on a rated obligation which is unlikely to be recovered.

• The rated entity files for protection from creditors, is placed into receivership, or is closed by regulators such that a missed payment is likely to result.

• The rated entity seeks and completes a distressed exchange, where existing rated obligations are replaced by new obligations with a diminished economic value.

KBRA may append - or + modifiers to ratings in categories AA through CCC to indicate, respectively, upper and lower risk levels within the broader category.

Short-Term Credit Rating Scale

K1+: Exceptional ability to meet short-term obligations.

K1: Very strong ability to meet short-term obligations.

K2: Strong ability to meet short-term obligations.

K3: Adequate ability to meet short-term obligations.

B: Questionable ability to meet short-term obligations.

C: Little ability to meet short-term obligations.

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D: KBRA defines default as occurring if:

• There is a missed interest payment, principal payment, or preferred dividend payment, as applicable, on a rated obligation which is unlikely to be recovered.

• The rated entity files for protection from creditors, is placed into receivership, or is closed by regulators such that a missed payment is likely to result.

• The rated entity seeks and completes a distressed exchange, where existing rated obligations are replaced by new obligations with a diminished economic value.

With exceptions for certain issuers and sectors, the following correspondence between KBRA’s short- and long-term ratings generally holds:

Long-Term Rating	Short-Term Rating
AAA	K1+
AA+
AA
AA-
A+	K1+ or K1
A	K1
A-	K1 or K2
BBB+	K2
BBB	K2 or K3
BBB-	K3
BB+	B
BB
BB-
B+
B
B-
CCC+	C
CCC
CCC–
CC
C
D	D

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APPENDIX B — THE INVESTMENT MANAGER’S PROXY VOTING PRINCIPLES AND PROCEDURES MANUAL

Corporate Governance and Proxy Voting Principles

This document sets out our views and more detail on key issues and the broad principles that help shape our approach as we seek to votes proxies in clients’ best long-term economic interests pursuant to our Proxy Voting Policy.

As active investors, well informed investment research and stewardship of our clients’ investments are important aspects of our responsible investment activities. Our approach to this is framed in the relevant Responsible Investment Policies we maintain and publish. These policy documents provide an overview of our approach in practice (e.g., around the integration of environmental, social and governance (ESG) and sustainability research and analysis).

As part of this, acting on behalf of our clients and as shareholders of a company, we are charged with responsibility for exercising the voting rights associated with that share ownership. Unless clients decide otherwise, that forms part of the stewardship duty we owe our clients in managing their assets. Subject to practical limitations, we therefore aim to exercise all voting rights for which we are responsible, although exceptions do nevertheless arise (for example, due to technical or administrative issues, including those related to Powers of Attorney, share blocking, related option rights or the presence of other exceptional or market-specific issues). This provides us with the opportunity to use those voting rights to express our views on relevant aspects of the business of a company, to highlight concerns to the board, to promote good practice and, when appropriate, to exercise related rights. In doing so, we have an obligation to ensure that we do that in the best long-term economic interests of our clients and in keeping with the mandate we have from them.

Corporate governance has particular importance to us in this context, which reflects our view that well governed companies are better positioned to manage the risks and challenges inherent in business, capture opportunities that help deliver sustainable growth and returns for our clients. Governance is a term used to describe the arrangements and practices that frame how directors and management of a company organize and operate in leading and directing a business on behalf of the shareholders of the company.

Such arrangements and practices give effect to the mechanisms through which companies facilitate the exercise of shareholders’ rights and define the extent to which these are equitable for all shareholders.

We recognize that companies are not homogeneous and some variation in governance structures and practice is to be expected. In formulating our approach, we are also mindful of best practice standards and codes that help frame good practice, including international frameworks and investment industry guidance. While we are mindful of company and industry specific issues, as well as normal market practice, in considering the approach and proposals of a company we are guided solely by the best long-term economic interests of our clients along with their mandate and will consider any issues and related disclosures or explanations in that context.

Shareholder Rights

The shareholder membership of listed companies is generally made up (directly or indirectly) of diverse individuals and institutions whose views, interests, goals and time horizons can vary considerably.

Nevertheless, as shareholders, having confidence that the capital we commit to a company will be protected from misuse (e.g. from any potential agency conflicts) and will be prudently managed is important to us, our clients, and as a factor in the development and proper functioning of capital markets.

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It is not the role of shareholders to micromanage businesses, rather it is the role and duty of directors to promote the long-term success of their company as noted in the next section. Nevertheless, by virtue of their share-ownership interest and position, shareholders are afforded certain rights to ensure, amongst other things, that appropriate leadership of the business is in place (e.g. through the appointment of the directors), review their performance (e.g. through receipt of the annual report & accounts, updates and general meetings), approve the broad parameters of the company’s authorities (e.g. in agreeing capital authorities), approve the appointment or ratification of external auditors, or indeed to exercise other rights afforded to shareholders (e.g. to requisition matters for consideration at General meetings).

Shareholder rights, framed in law, regulation and a company’s formational documents (i.e., bylaws or articles of association), are an important and integral part of corporate governance frameworks and the context in which we retain confidence in committing capital to businesses, to support their growth, development and success. This is particularly true in terms of ensuring that minority shareholders’ rights and interests will be respected. Arrangements or actions that detract from these rights and interest (including control distortions) need to be avoided.

While the precise nature and scope of shareholder rights vary across jurisdictions and many related aspects of our expectations are touched upon in other parts of these Principles, a number merit direct mention in this context:

Equal treatment of all shareholders

One share one vote: Ordinary or common shares should feature one vote for each share and discriminatory voting rights or equivalent arrangements are neither appropriate nor welcome. Companies need to disclose sufficient information about the key attributes of all of the group’s capital structure (including minority interests in subsidiaries) to enable a proper understanding of the structures in place and their implications.

Controlling shareholder agreements: where a company has a controlling shareholder (whether by virtue of the control of voting rights or through board representation) it should put an agreement in place to safeguard the independence of the company and ability of the board to fulfill its duties to the shareholders as a whole.

Shareholder approvals

Boards should ensure that shareholders have the ability and right to:

• effectively exercise their voting rights across the full range of business normally associated with general meetings of a company in line with market best practice (e.g. the election of individual directors, discharge authorities, capital authorities, auditor appointment, major or related party transactions etc.).

• place items on the agenda of general meetings, and to propose resolutions subject to reasonable limitations;

• call a meeting of shareholders for the purpose of transacting the legitimate business of the company; and

that shareholder rights are not circumvented through, for example, the introduction or maintenance of limitations in the company’s formational documents.

Shareholder engagement

Boards should ensure that:

• Clear, consistent and effective reporting to shareholders is undertaken at regular intervals and that they remain aware of shareholder sentiment on major issues to do with the business, its strategy and performance. Where significant shareholder dissent is emerging or apparent (e.g. through the voting levels seen at General Meetings), boards should act to address that.

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• Boards should also allow a reasonable opportunity for the shareholders at a general meeting to ask questions about or make comments on the management of the company, and to ask the external auditor questions related to the audit.

As an institutional shareholder, stewardship is about more than just voting and include monitoring and reviews of companies’ activities and developments. Where appropriate it may also include engagement with companies on matters such as strategy, performance, risk, capital structure, standards of operational practice, including environmental, social and governance factors. Our broad approach to these stewardship responsibilities and activities are set out in our Global Stewardship Statement.

Shareholder resolutions

Shareholder resolutions represent the exercise of a key shareholder right and may encompass a wide range of issues.

As such, we assess shareholder resolutions in light of good practice, the standards already applied by a company, how proportionate the proposals are, their alignment with our philosophy and approach, as well any potential conflicts with our clients’ interests. We will incorporate into our decision whether a shareholder resolution is binding in nature or advisory (non-binding) in applying these considerations.

The Board

Strong corporate governance starts with a balanced, effective, and independent board. The directors are collectively responsible for the long-term success and ongoing evolution in the leadership of the company, within a framework of prudent and effective oversight, policies and controls.

The board is thus responsible for providing leadership to the business, setting and monitoring the strategy, overseeing its management and implementation, as well as for ensuring that a culture of integrity and strong standards is maintained across all activities and operations. Not least this should enable business opportunities and risk to be assessed and responded to appropriately.

Boards need to have appropriate independent membership and an effective balance and diversity (re: skills, knowledge, experience, race/ethnicity, gender, approach and perspectives) that complements the strategy, operations and footprint of the business. For non-executive (supervisory) directors (NEDs),the ability to provide objective input and scrutiny, on behalf of the shareholders, is essential in ensuring diversity of thought and integrity in board deliberations. In this context, the importance of true independence of thought is critical. NEDs need to be reflective and thoughtful in their approach, being able to ask challenging, often difficult questions, while offering considered and constructive input to board discussions, based on sound judgement. The same holds true in terms of board committee membership.

Suitably independent committees are one important mechanism for non-executive supervisory directors to achieve this, whether that is in respect of risk, audit, succession or remuneration, so as to enable them to participate effectively as part of the board and in their role as directors of the business.

As part of this dynamic, well considered succession planning, orientation, on-going briefings, updates and annual evaluations (that make regular use of external facilitation) of the board, its sub-committees and members are essential.

All directors should be able to allocate sufficient time to the company to discharge their responsibilities fully and effectively and have an appropriate knowledge of the business and access to its operations and staff. Given the important role and duties of a board member, it is important that directors are not over-boarded and can maintain consistent participation at all their board and committee meetings and their wider engagement with the companies they lead.

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All directors should be subject to annual election. However, in markets where that is not normal or best practice, we expect all directors to be subject to re-election in line with local market best practice, but in any case, at least every four years. At the same time, arrangements that might entrench boards or management, or otherwise insulate them from accountability, should be avoided.

Given their role and duties, directors should also ensure that they are well informed about the views and/or concerns of shareholders, as well as understanding the dynamic around their broader stakeholders (including bondholders, pension fund trustees, employees, customers, suppliers and the communities they operate in).

Chair of the Board

The Board Chair has a crucial function in providing leadership in the boardroom, setting the right context in terms of the board’s overall responsibility for the oversight of the business and its strategy. It is the Board Chair’s role to manage the board agenda and the provision of information to directors, as well as to ensure open boardroom discussion that enables the directors to have effective dialogue and provide the constructive challenge that a company needs. This role is distinct from the role of a chief executive officer who leads the day-to-day running of the business and implementation of the strategy.

We expect the Board Chair (or lead/senior independent director) to ensure that the board is aware of the views and considers concerns raised by shareholders, whether through ongoing dialogue and engagement with shareholders or where notable dissent has been indicated through shareholder voting.

We recognize that in some markets the combination of roles is not uncommon, nevertheless we regard the separation of the roles of the Board Chair and the CEO to be a matter of good practice and governance. In light of experience, we consider that this separation encourages collegial decision-making on matters of importance for a public company, and a balanced board, and it also mitigates potential conflicts of interest. Not least it also helps mitigate against the risk of a concentration of decision making powers in the hands of a single individual. Separation is deemed to improve the board’s capacity for independent decision making and increases accountability.

The Chair of the Board’s role should be complemented by an independent non-executive director appointed as the senior or lead independent director, who can provide a sounding board for the chair and serve as a deputy and intermediary for the other directors and, indeed, shareholders when necessary.

Capital Management

Prudent capital management is a key building block for the long-term success of a business, supporting the strategy and ensuring its ability to weather adverse economic conditions. Clarity on the capital structure plans, related disciplines and how they relate to the strategy for growth, capital investment and M&A, or to share buybacks, dividends and/or other distributions, is a critical ingredient in building a shared understanding of the business with shareholders and other providers of capital.

From a shareholder perspective the rationale for and potential dilution from equity capital issuances and, for example, the risks of poorly timed or structured share buybacks are important considerations in granting capital authorities at shareholder meetings. These activities can have significant implications and need to be approached by boards and management with care and consideration for shareholder interests.

In seeking shareholder approval for equity capital issuance authorities, companies should ensure the rationale for policy on, and approach to, the use of such authorities is disclosed. Routine disapplication of pre-emption rights (pro-rata rights of first refusal) should not exceed 10% (or lower where that is market practice) and authorities should be structured in line with best practice.

Similarly, prudent management of debt through the cycle is important. Boards should ensure they monitor and oversee the maintenance of prudent levels of debt (e.g. average net-debt not just the year-end position) and

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leverage in the business and balance sheet, which should extend to contingent and off-balance sheet liabilities. They should also ensure that sudden spikes in leverage can be explained in the context of the broader long-term business strategy. Large, unexplained or unjustified authorities to issue debt, or to increase or remove debt limits set out in a company’s formational documents, can raise potentially significant concerns for both long-term shareholders and bondholders, which the board needs to be mindful of.

Taking on debt solely to fund buybacks and/or hit ‘per-share’ targets such as EPS established under short- term variable remuneration schemes should be explained and a robust rationale provided.

Any exceptional cases should be supported by a substantive justification and explained properly to shareholders.

Major Transactions

Mergers, acquisitions, joint ventures and disposals are a regular feature of business and the capital markets. In many cases these are a normal part of the management and development of a business and the implementation of its strategy. However, large, inappropriate or poorly executed transactions can also lead to operational issues, significant write-downs and shareholder value destruction.

Boards should be actively involved in the planning for and assessment of potential transactions, ensuring that an appropriately disciplined approach (to both acquisitions and disposals) is maintained that is clearly aligned with the strategy. Ensuring appropriate and effective oversight of such activity is critical and monitoring the integration and subsequent performance against plan and related objectives (including synergies) is an important role of the board.

Where major transactions are not subject to shareholder approval, companies should consider the views of their major shareholders, subject to regulatory constraints and shareholders’ policies on being made “insiders”.

Related Party Transactions

The scope for conflicts and abuse in related party transactions in any market is a potentially significant issue. Such concerns can arise in relation to individual transactions or from the number, nature or pattern of them. Alongside appropriate procedures to identify and manage conflicts of interest, boards should have a robust, independent process for reviewing, approving and monitoring related party transactions (both individual transactions and in aggregate).

A committee of independent directors, with the ability to take independent advice, should review related party transactions, their nature and their incidence or aggregate levels, to determine whether they are necessary, appropriate and in the best interests of the company and, if so, agree what terms are fair for other shareholders. All related party transactions should be reported to the board and be subject to approval.

The company should also disclose transactions that are significant, whether by virtue of their materiality to the business, the individuals involved or given the risk of perceived conflicts of interest, along with the rationale for allowing them.

Where a related party transaction is allowed to proceed it must be:

• subject to proper oversight by the board and regular review (e.g. audit, shareholder approval);

• clearly justified and not be detrimental to the long-term interests of the company;

• undertaken in the normal course of business;

• undertaken on fully commercial terms;

• in line with best practice; and

• in the interests of all shareholders.

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Tax Management

Tax management approached prudently and legally, is part of the responsible management of a company’s affairs. Artificial or ‘aggressive’ tax strategies and constructs create imprudent risks for a company.

They can pose potentially significant reputation and commercial risks for those that are, or are perceived to be, pushing the boundaries of tax practice by, for example, exploiting loopholes and tax havens to avoid paying tax. The same reputation risks hold in respect of the directors of companies involved in such practices and the perception of the culture and attitudes it evidences. This applies equally to the use of tax avoidance structures in executive compensation arrangements, as it does at a corporate level.

From an investor perspective, tax management offers an insight into the culture predominant in a company and the attitudes and risk appetite of the management and directors. It also offers an additional indicator on the quality of earnings, risk and potential liabilities of a business, which can be relevant in terms of valuation and the investment quality of a business.

We expect the board to take a responsible approach to overseeing a company’s approach to and policy on tax and the related risks, to ensure that the company’s approach is and remains prudent and sustainable. The risks arising from engineered tax optimization practices should be understood and avoided; those arising from policy reforms (e.g. those being coordinated by the Organisation for Economic Co-Operation and Development (OECD) and other authorities) should be properly mitigated. The board should regularly review the business’s tax policy, its implementation and the related risks, as well as in response to significant events that may affect it. A summary of the tax policy and related codes of conduct should be published by companies, highlighting the approach to managing the associated risks.

In terms of changes in tax domicile or re-incorporation, while economic benefit may be gained, there should be no diminution of shareholders rights as a result of the changes, nor triggering of variable compensation as a result of the associated technical, legal or structural changes required.

Annual Reports and Accounts

Annual reports and accounts are a key reference document for shareholders and the providers of a company’s long-term capital. They should provide a summary account of the board’s stewardship of the business that year (as opposed say to being designed or prepared for a secondary market context i.e. decision usefulness), whilst setting a direction of travel for the future.

In the annual report, the board should present a fair, balanced and understandable assessment of the company’s strategy, business plan, objectives, KPIs, capital and assets, operations, risks, challenges, performance and prospects in its annual report. This should include how the business’ approach is adapting to major trends (e.g. from technology, climate change or demographics etc.) that could have a material impact on the business and the related risks and opportunities it sees and how they affect the sustainability of the business and its long-term prospects.

The annual financial statements (accounts) need to be prepared on a prudent basis and present a true and fair view of the state of affairs of the business, its assets, liabilities, financial position and distributable profit or the loss. Boards should ensure that aggressive accounting practices are avoided and recognize that headline compliance with accounting standards, where significant judgement and discretion can be used, is unlikely of itself to effectively provide comfort that a ‘true & fair view’ is being maintained. Boards should ensure company practice does not fall into the trap of accounting form over substance.

The annual report and accounts are a reflection of the quality and prudence of management and the board of directors. Managements should strive for perfection in delivering these important documents. Errors and omissions may ultimately factor in our view toward the constitution and effectiveness of management and the board.

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While recognizing the differences that exist in market norms and dynamics, we expect companies to plan for and look to the long-term in their reporting. The board should ensure that the company does not become fixated on quarterly numbers at the expense of investment for the long-term.

External Audit

The statutory audit is a significant and important shareholder and creditor protection mechanism, to which we attach considerable importance. Its purpose is to protect the company itself from errors, omissions or, potentially, wrongdoing, as well as to signal any issues to shareholders to enable them to engage with the directors, not least through the general meeting.

Companies should, therefore, ensure that the relationship with the auditor is clearly owned and overseen by the Audit Committee and that they maintain a robust, independent and effective audit and that the auditors are and are seen to be independent. As part of this, companies should have a clear policy on the approach to and general timeframes relating to re-tendering the audit contract.

Non-audit work should be kept to a minimum, require prior audit committee approval and largely be restricted to audit related work. Audit committees should also oversee any work undertaken by other audit firms to ensure that the company’s options and choice of alternative auditors is not compromised by potential conflicts.

Internal Audit and Risk Committees

Companies need to maintain an effective system of internal control, which should be measured against internationally accepted standards of internal audit and tested periodically for its adequacy.

Companies are encouraged to have an internal audit function that supports the board and executives in the oversight and management of risks. We expect financial institutions to maintain a separate risk committee and support this practice, where appropriate, in other companies.

Compensation/Remuneration

Executive pay has been a persistent area of concern and controversy over the years. Given the problems around executive pay inflation, widening pay differentials, questions about the linkage with performance and perceived rewards for failure, and complexity, compensation (remuneration) committees need to ensure a prudent approach is maintained.

We expect a substantial proportion of executive pay to be performance based, vesting according to the achievement of stretching performance metrics that are clearly aligned with the company’s strategy, management’s value creation and the experience of its shareholders. In terms of pay and overall employee costs, we will have particular regard to the relative levels of pay compared to the performance of the business, distributions to shareholders.

In relation to any accompanying pensions arrangements, including cash contributions in lieu thereof as well as benefits more broadly, we expect applicable valuations (i.e. contribution rates in the context of pensions) to be set prudently under the circumstances. Where any pensions benefit provided to executives is enhanced as compared to equivalent benefits provided to the wider workforce, we will consider this in our evaluation of the fairness and proportionality of the total remuneration package.

Across a company’s pay arrangements, structural or technical provisions that can weaken or undermine the principle of pay for performance, need to be avoided, and change-in-control arrangements should be prudent and not linked to outlier practices. Similarly, we are generally supportive of local market best practices that enhance the alignment of pay and performance, such as retention and deferral arrangements, malus/clawback, reasonable all-employee share schemes etc. Consideration should also be given to the disclosures required around pay ratios and the ramifications for the companies in which we invest.

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Broadly speaking, compensation (remuneration) committees should look to ensure that their company’s pay arrangements are:

1. Clear, simple and understandable;

2. Balanced and proportionate, in respect of structure, deliverables, opportunity and the market;

3. Aligned with the long-term strategy, related key performance indicators and risk management discipline;

4. linked robustly to the delivery of performance;

5. Delivering outcomes that reflect value creation and the shareholder ‘experience’; and

6. Structured to avoid pay for failure or the avoidance of accountability to shareholders.

Where a company consults with its shareholders on its executive pay arrangements, the compensation (remuneration) committee chair should take ownership and lead that process, ensuring proper two-way dialogue, as deference to consultants undermines credibility. That said, pay is only one aspect of the dialogue we need to have or prioritize with companies. As a result, we would note that, generally, we only look to participate directly in such consultations where we are a significant shareholder.

Corporate Responsibility

Well run or improving companies are better positioned to adapt to and manage the risks and challenges inherent in business. As investors, a holistic focus on the characteristics and exposures of a business provides us with a valuable insight into important aspects of the opportunities it has and its quality.

Sustainability themes

Sustainability themes (whether social or environmental in nature) are catalysts of change, creating both risks and opportunities. A company’s ability not only to adapt to but also to capitalize on the opportunities such themes highlight - by innovating and commercializing solutions (outputs, products or services) that respond to them – are relevant to investors given the long-term economic benefits they can generate for investors. Companies should make appropriate and integrated disclosures reflecting touch points for their strategy, R&D, capex, operational performance and commercial aspirations.

In doing so, companies should be mindful of the growing interest that exists amongst investors and other stakeholders in how a company’s approach to sustainability themes is aligned with the policy principles set out in the UN Sustainable Development Goals (SDGs). Impact oriented investment is a small but fast-growing part of the investment landscape.

Environmental, Social and Governance (ESG) Practices

A company’s recognition and management of its material ESG exposures and related disclosures provide shareholders with an additional lens through which to assess the quality, leadership, strategic focus, risk management and operational standards of practice of a business. Reflecting our philosophy on the importance of integrating ESG considerations into our assessment of how well a business is run, we will consider the level and effectiveness of ESG disclosure made by companies in their annual reports and other materials. Our focus will be on those factors deemed material to businesses in a given sector, with a focus on practices that we consider are unsustainable, create potential risks or adverse impacts to stakeholders, or which are in need of improvement to avoid erosion of shareholder value.

As investors, in framing and assessing what are the material ESG factors for a business, we draw on the Sustainability Accounting Standards Board (SASB)’s materiality framework. SASB’s mission is to help businesses identify, manage and report on the sustainability topics that matter most given their industry. Their

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standards have been developed based on extensive research and feedback from companies, investors, and other market participants as part of a transparent, publicly-documented process. While companies may have specific exposures unique to their circumstances, the SASB standards form the basis and starting point for assessing and monitoring a company’s ESG characteristics and their economic impact

Where management and the board have not demonstrated adequate standards of practice, or effort to be transparent in how they address and mitigate material ESG issues or are considered to be failing to adequately address current or emergent risks that may threaten shareholder value in the future, we may take voting action to highlight this.

Climate risk

Climate risk is and will increasingly be a focus for companies and investors. The growing number of regulatory interventions and the public debate around climate change make this a distinct issue in its own right.

The 2016 Paris Agreement set a number of globally agreed goals on climate change and greenhouse gas emissions reduction. Policy interventions, regulatory changes and initiatives, such as the Financial Stability Board’s Taskforce on Climate Related Financial Disclosures (TCFD), provide a clear indication of the importance attached to this issue.

The TCFD recommendations provide a framework in which climate related issues can be assessed and disclosed, to enable:

i. an understanding how resilient an organization’s strategy is to climate-related risks;

ii. appropriate pricing of climate related risks and opportunities; and a

iii. a broad understanding of the financial systems’ exposure to climate related risk.

As investors, we recommend the TCFD framework for facilitating the development of effective disclosures. These disclosures, as well as those sought by CDP, are ever more important in the assessments that need to be made by investors. A company’s exposure and approach to climate change, related plans, risks, standards and targets, as well as the operational and commercial opportunities being pursued, are increasingly ‘decision useful’ matters to investors and can have a direct impact on shareholder value.

Where management and the board have not provided adequate or relevant disclosures to facilitate and enable effective assessments of how climate risks are being addressed and mitigated in practice, we may take voting action to highlight this.

International standards of practice

Generally accepted international standards and principles provide investors with clear frameworks to assess issues and controversies (‘adverse impacts’) surrounding or arising from a business and its operations.

We place particularly importance on the following in our approach:

• UN Global Compact

• UN Guiding Principles on Business and Human Rights (the “Ruggie Principles”)

• International Labour Organisation (ILO) Core Labor Standards

Where issues arise that suggest a failure to meet generally accepted international standards and principles, this raises questions about a company’s management, culture, operating standards and risks. Where such issues arise, this will be taken into account as part of our deliberations on voting action.

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APPENDIX C — INFORMATION REGARDING PENDING AND SETTLED LEGAL PROCEEDINGS

Ameriprise Financial and certain of its affiliates have historically been involved in a number of legal, arbitration and regulatory proceedings, including routine litigation, class actions, and governmental actions, concerning matters arising in connection with the conduct of their business activities. Ameriprise Financial believes that the Funds are not currently the subject of, and that neither Ameriprise Financial nor any of its affiliates are the subject of, any pending legal, arbitration or regulatory proceedings that are likely to have a material adverse effect on the Funds or the ability of Ameriprise Financial or its affiliates to perform under their contracts with the Funds. Ameriprise Financial is required to make quarterly (10-Q), annual (10-K) and, as necessary, 8-K filings with the SEC on legal and regulatory matters that relate to Ameriprise Financial and its affiliates. Copies of these filings may be obtained by accessing the SEC website at sec.gov.

There can be no assurance that these matters, or the adverse publicity associated with them, will not result in increased fund redemptions, reduced sale of fund shares or other adverse consequences to the Funds. Further, although we believe proceedings are not likely to have a material adverse effect on the Funds or the ability of Ameriprise Financial or its affiliates to perform under their contracts with the Funds, these proceedings are subject to uncertainties and, as such, we are unable to estimate the possible loss or range of loss that may result. An adverse outcome in one or more of these proceedings could result in adverse judgments, settlements, fines, penalties or other relief that could have a material adverse effect on the consolidated financial condition or results of operations of Ameriprise Financial or one or more of its affiliates that provides services to the Funds.

NO PERSON HAS BEEN AUTHORIZED TO GIVE ANY INFORMATION OR TO MAKE ANY REPRESENTATIONS NOT CONTAINED IN THE PROSPECTUS OR IN THIS STATEMENT OF ADDITIONAL INFORMATION, WHICH EACH PROSPECTUS INCORPORATES BY REFERENCE, IN CONNECTION WITH THE OFFERING MADE BY EACH PROSPECTUS AND, IF GIVEN OR MADE, SUCH INFORMATION OR PRESENTATIONS MUST NOT BE RELIED UPON AS HAVING BEEN AUTHORIZED BY THE TRUST. THIS STATEMENT OF ADDITIONAL INFORMATION DOES NOT CONSTITUTE AN OFFERING BY THE TRUST IN ANY JURISDICTION IN WHICH SUCH AN OFFERING MAY NOT LAWFULLY BE MADE.

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APPENDIX S — MORE INFORMATION ABOUT CHOOSING A SHARE CLASS

The Funds’ prospectuses contain information about choosing a share class. The information in this Appendix S should be read in conjunction with the information contained in the prospectuses. With regard to any sales charge waivers and discounts described in this Appendix S and the prospectuses, it is your obligation to advise your Financial Intermediary or (in the case of Direct-at-Fund Accounts, as defined in the prospectuses) the Transfer Agent that you qualify for any waiver or reduced sales charge and be prepared to provide proof thereof.

Sales Charge Reductions

Front-End Sales Charge Waivers (Class A Shares)*

The following information is in addition to the description in the Funds’ prospectuses of front-end sales charge waivers applicable to Class A shares. The following categories of investors may buy Class A shares at NAV, without payment of any front-end sales charge that would otherwise apply:

• Current or retired directors or trustees of the Columbia Funds, and officers or employees of Columbia Management or its affiliates, including the Investment Manager;

• Current or retired Ameriprise Financial Services, LLC financial advisors and employees of such financial advisors;^(a)

• Registered representatives and other employees of affiliated or unaffiliated financial intermediaries having a selling agreement with the Distributor;^(a)

• Registered broker-dealer firms that have entered into a dealer agreement with the Distributor may buy Class A shares without paying a front-end sales charge for their investment account only;

• Portfolio managers employed by any sub-adviser of the Columbia Funds;^(a)

• Partners and employees of outside legal counsel to the Columbia Funds or to the Columbia Funds’ directors or trustees who regularly provide advice and services to the Columbia Funds, or to their directors or trustees;

• Direct rollovers (i.e., a rollover of Fund shares and not a reinvestment of redemption proceeds) from qualified employee benefit plans, provided that the rollover involves a transfer to Class A shares in the same Fund or Columbia Fund;

• Employees or partners of the Investment Manager;

• Separate accounts established and maintained by an insurance company which are exempt from registration under Section 3(c)(11);

• At a Columbia Fund’s discretion, front-end sales charges may be waived for shares issued in plans of reorganization, such as mergers, asset acquisitions and exchange offers, to which the Columbia Fund is a party;

• Purchases by registered representatives and employees (and their immediate family members and related trusts or other entities owned by the foregoing (referred to as “Related Persons”)) of Ameriprise Financial Services, LLC and its affiliates; provided that with respect to employees (and their Related Persons) of an affiliate of Ameriprise Financial, such persons must make purchases through an account held at Ameriprise Financial or its affiliates.

* Any shareholder with a Direct-at-Fund account (i.e., shares held directly with the Fund through the Transfer Agent) that is eligible to purchase shares without a front-end sales charge by virtue of having qualified for a previous waiver may continue to purchase shares without a front-end sales charge if they no longer qualify under a category described in the prospectus or in this section. Otherwise, you must qualify for a front-end sales charge waiver described in the prospectus or in this section.

(a) Including their spouses or domestic partners, children or step-children, parents, step-parents or legal guardians, and their spouse’s or domestic partner’s parents, step-parents, or legal guardians.

S-1

Purchases of Class A shares may be made at NAV if they are made as follows:

• Through or under a wrap fee product or other investment product sponsored by a financial intermediary that charges an account management fee or other managed agency/asset allocation accounts or programs involving fee-based compensation arrangements that have or that clear trades through a financial intermediary that has a selling agreement with the Distributor;

• Through state sponsored college savings plans established under Section 529 of the Internal Revenue Code;

• Through banks, trust companies and thrift institutions, acting as fiduciaries; or

• Through “employee benefit plans” created under Section 401(a), 401(k), 457 and 403(b), and qualified deferred compensation plans, that have a plan level or omnibus account maintained with a Columbia Fund or the Transfer Agent and transacts directly with the Columbia Fund or the Transfer Agent through a third party administrator or third party recordkeeper. This waiver does not apply to accounts held through commissionable brokerage platforms.

Contingent Deferred Sales Charges (Class A and Class C Shares)

For purposes of calculating a CDSC, the start of the holding period is generally the first day of the month in which your purchase was made.

Shareholders won’t pay a CDSC upon redemption of Class A or Class C shares:

• In the event of the shareholder’s death;

• For which no sales commission or transaction fee was paid to an authorized financial intermediary at the time of purchase;

• Purchased through reinvestment of dividend and capital gain distributions;

• That result from required minimum distributions taken from retirement accounts upon the shareholder’s attainment of the qualified age based on applicable IRS regulations;

• That result from returns of excess contributions made to retirement plans or individual retirement accounts, so long as the financial intermediary returns the applicable portion of any commission paid by the Distributor;

• Of Class A shares of a Fund initially purchased by an employee benefit plan;

• Of Class C shares of a Fund initially purchased by an employee benefit plan that are not connected with a plan level termination;

• In connection with the Fund’s Small Account Policy (as described in the applicable prospectus); and

• At a Fund’s discretion, issued in connection with plans of reorganization, including but not limited to mergers, asset acquisitions and exchange offers, to which the Fund is a party.

Restrictions may apply to certain accounts and certain transactions. The Distributor may, in its sole discretion, authorize the waiver of the CDSC for additional classes of investors. The Fund may change or cancel these terms at any time. Any change or cancellation applies only to future purchases.

Class Inst Shares Additional Eligible Investors

In addition to the categories of Class Inst investors described in the Funds’ prospectuses, the minimum initial investments in Class Inst is $2,000 ($1,000 for IRAs, as applicable):

• Any client of Bank of America or one of its subsidiaries buying shares through an asset management company, trust, fiduciary, retirement plan administration or similar arrangement with Bank of America or the subsidiary.

S-2

• Any employee (or family member of an employee) of Bank of America or one of its subsidiaries.

• Any investor buying shares through a Columbia Management state tuition plan organized under Section 529 of the Internal Revenue Code.

• Any trustee or director (or family member of a trustee or director) of a fund distributed by the Distributor.

Any shareholder (as well as any family member of a shareholder or person listed on an account registration for any account of the shareholder) who holds Class Inst shares of a fund distributed by the Distributor is eligible to purchase Class Inst shares of other funds distributed by the Distributor, subject to a minimum initial investment of $2,000 ($1,000 for IRAs). If the account in which the shareholder holds Class Inst shares is not eligible to purchase additional Class Inst shares, the shareholder may purchase Class Inst shares in an account maintained directly with the Transfer Agent, subject to a minimum initial investment of $2,000 ($1,000 for IRAs).

Fund Reorganizations

Class A shares may be issued without any initial sales charge in connection with the acquisition of cash and securities owned by other investment companies. Any CDSC will be waived in connection with the redemption of shares of a Fund if the Fund is combined with another Fund or in connection with a similar reorganization transaction.

Rejection of Purchases

Each Fund and the Distributor reserve the right to reject any offer to purchase shares, in their sole discretion.

Class C Share Conversions

Class C shares held through a financial intermediary may be converted, in the discretion of the Fund, to Class A shares sooner than the general conversion schedule in connection with the withdrawal of the Fund’s Class C shares from such financial intermediary’s platform or accounts. In the event of such conversion, the Distributor will provide at least 30 days’ written notice to such financial intermediary. No sales charge or other charges apply in connection with such a conversion, and conversions are free from U.S. federal income tax.

S-3

PART C OTHER INFORMATION

Item 28. Exhibits

Note: As used herein, the term “Post-effective Amendment” refers to a post-effective amendment to the registration statement of Registrant or its predecessor, The Acorn Fund, Inc., under the Securities Act of 1933 on form S-5, N-1 or N-1A, no. 2-34223.

a.1 Agreement and Declaration of Trust (1)

a.2 Amendment No. 1 to Agreement and Declaration of Trust. (3)

a.3 Amendment No. 2 to Agreement and Declaration of Trust. (4)

b. Bylaws dated September 28, 2004, as amended through September 21, 2016. (14)

c. None.

d.1 Organizational Expenses Agreement between Acorn Investment Trust (now known as Columbia Acorn Trust) and Wanger Asset Management, L.P. (now known as Columbia Wanger Asset Management, LLC), dated September 3, 1996. (2)

d.2 Organizational and Offering Costs Agreement between Columbia Acorn Trust and Columbia Wanger Asset Management, LLC (relating to Columbia Acorn European Fund and Columbia Acorn Emerging Markets Fund) dated August 17, 2011. (9)

d.3 Investment Advisory Agreement between Columbia Acorn Trust and Columbia Wanger Asset Management, LLC dated May 27, 2010, Schedules A and B last amended June 8, 2011. (9)

d.4 Investment Advisory Fee Reduction Agreement between Columbia Acorn Trust, on behalf of Columbia Acorn International Select, and Columbia Wanger Asset Management, LLC dated July 1, 2016. (14)

d.5 Investment Advisory Fee Reduction Agreement between Columbia Acorn Trust, on behalf of Columbia Acorn USA, and Columbia Wanger Asset Management, LLC dated May 1, 2022.

d.6 Administrative Services Agreement between Columbia Acorn Trust and Columbia Wanger Asset Management, LLC dated May 1, 2010, (the “Administrative Services Agreement”), Schedule A last amended June 8, 2011. (9)

d.7 Amendment No. 1 dated September 21, 2016 to the Administrative Services Agreement. (14)

d.8 Schedule B to the Administrative Services Agreement, amended September 19, 2019. (15)

e.1 Distribution Agreement between Columbia Acorn Trust and Columbia Management Investment Distributors, Inc. dated May 1, 2010, (the “Distribution Agreement”), Schedules I and II last amended June 8, 2011. (9)

e.2 Amendment dated April 12, 2011 to the Distribution Agreement. (9)

e.3 Amendment No. 2 dated September 21, 2016 to the Distribution Agreement. (14)

f. None.

g. Custody Agreement among JPMorgan Chase Bank, N.A., Columbia Acorn Trust and Wanger Advisors Trust dated December 15, 2010, effective July 22, 2011, with Addendums dated July 14, 2011. (9)

h.1 Amended and Restated Transfer, Dividend Disbursing and Shareholders’ Servicing Agent Agreement between Columbia Acorn Trust and Columbia Management Investment Services Corp. dated May 1, 2012 (the “Transfer Agent Agreement”). (10)

h.2 Amendment No. 1 dated September 21, 2016 to the Transfer Agent Agreement. (14)

h.3 Compliance Agreement between Columbia Acorn Trust and Ameriprise Financial, Inc. dated May 1, 2010. (7)

h.4 Fee Waiver/Expense Reimbursement Agreement between Columbia Acorn Trust and Columbia Wanger Asset Management, LLC, relating to Columbia Acorn International, dated May 1, 2022.

h.5 Fee Waiver/Expense Reimbursement Agreement between Columbia Acorn Trust and Columbia Wanger Asset Management, LLC, relating to Columbia Acorn USA, dated May 1, 2022.

h.6 Fee Waiver/Expense Reimbursement Agreement between Columbia Acorn Trust and Columbia Wanger Asset Management, LLC, relating to Columbia Thermostat Fund, dated May 1, 2022.

h.7 Fee Waiver/Expense Reimbursement Agreement between Columbia Acorn Trust and Columbia Wanger Asset Management, LLC, relating to Columbia Acorn Fund, dated May 1, 2022.

h.8 Fee Waiver/Expense Reimbursement Agreement between Columbia Acorn Trust and Columbia Wanger Asset Management, LLC, relating to Columbia Acorn European Fund, dated May 1, 2022.

h.9 Fee Waiver/Expense Reimbursement Agreement, relating to Columbia Acorn International Select, between Columbia Acorn Trust and Columbia Wanger Asset Management, LLC, dated July 1, 2016. (14)

h.10 Fee Waiver/Expense Reimbursement Agreement, relating to Columbia Acorn International Select, between Columbia Acorn Trust and Columbia Wanger Asset Management, LLC dated May 1, 2022.

h.11 Transfer Agent Fee Waiver Agreement between Columbia Acorn Trust and Columbia Management Investment Services Corp., dated May 1, 2022.

h.12 Participation Agreement among Merrill Lynch Life Insurance Company, Columbia Acorn Trust and Columbia Funds Distributor, Inc. (now named Columbia Management Distributors, Inc.) dated March 4, 2005. (5)

h.13 Amendment No. 1 to Participation Agreement among Merrill Lynch Life Insurance Company, Columbia Acorn Trust and Columbia Management Distributors, Inc. (formerly Columbia Funds Distributor, Inc.) dated March 30, 2007. (6)

h.14 Participation Agreement among ML Life Insurance Company of New York, Columbia Acorn Trust and Columbia Funds Distributor, Inc. (now named Columbia Management Distributors, Inc.) dated March 4, 2005. (5)

h.15 Amendment No. 1 to Participation Agreement among ML Life Insurance Company of New York, Columbia Acorn Trust and Columbia Management Distributors, Inc. (formerly Columbia Funds Distributor, Inc.) dated March 30, 2007. (6)

h.16 Amended and Restated Credit Agreement as of October 28, 2021.

i. Opinion letter and written consent of Perkins Coie LLP relating to the series of Columbia Acorn Trust.

j. Consent of independent registered accounting firm.

k. None.

l. None.

m.1 Plan of Distribution Pursuant to Rule 12b-1. (9)

m.2 Rule 12b-1 Plan Implementing Agreement. (9)

n.1 Amended and Restated Plan Pursuant to Rule 18f-3(d), effective February 1, 2021. (16)

o. Not applicable.

p.1 Columbia Threadneedle Investments Global Personal Account Dealing and Code of Ethics, effective December 2021.

p.2 Code of Ethics for Non-Management Trustees, as amended, effective as of September 19, 2012. (11)

(1) Incorporated by reference to post-effective amendment No. 53 to the Registrant’s registration statement on form N-1A, Securities Act registration number 2-34223 (the “Registration Statement”), filed on April 30, 1996.

(2) Incorporated by reference to Registrant’s post-effective amendment No. 61 to the Registration Statement filed on April 30, 1998.

(3) Incorporated by reference to Registrant’s post-effective amendment No. 70 to the Registration Statement filed on May 1, 2001.

(4) Incorporated by reference to Registrant’s post-effective amendment No. 77 to the Registration Statement filed on March 1, 2005.

(5) Incorporated by reference to Registrant’s post-effective amendment No. 79 to the Registration Statement filed on May 1, 2006.

(6) Incorporated by reference to Registrant’s post-effective amendment No. 80 to the Registration Statement filed on April 30, 2007.

(7) Incorporated by reference to Registrant’s post-effective amendment No. 87 to the Registration Statement filed on September 27, 2010.

(8) Incorporated by reference to Registrant’s post-effective amendment No. 88 to the Registration Statement filed April 29, 2009.

(9) Incorporated by reference to Registrant’s post-effective amendment No. 91 to the Registration Statement filed on August 17, 2011.

(10) Incorporated by reference to Registrant’s post-effective amendment No. 93 to the Registration Statement filed on April 27, 2012.

(11) Incorporated by reference to Registrant’s post-effective amendment No. 95 to the Registration Statement filed on November 7, 2012.

(12) Incorporated by reference to Registrant’s post-effective amendment No. 99 to the Registration Statement filed on April 30, 2014.

(13) Incorporated by reference to Registrant’s post-effective amendment No. 103 to the Registration Statement filed on April 29, 2016.

(14) Incorporated by reference to Registrant’s post-effective amendment No. 105 to the Registration Statement filed on April 28, 2017.

(15) Incorporated by reference to Registrant’s post-effective amendment No. 112 to the Registration Statement filed on April 29, 2020.

(16) Incorporated by reference to Registrant’s post-effective amendment No. 114 to the Registration Statement filed on April 28, 2021.

Item 29. Persons Controlled By or Under Common Control with Registrant

The Registrant does not consider that there are any persons directly or indirectly controlled by, or under common control with, the Registrant within the meaning of this item. The information in the prospectuses under the caption “Management of the Fund - Primary Service Providers - The Investment Manager” and in the statement of additional information under the caption “The Investment Manager and Investment Advisory Services” is incorporated by reference.

Item 30. Indemnification

Article VIII of the Agreement and Declaration of Trust of the Registrant (listed as Exhibit a.1 and incorporated in this filing by reference) provides in effect that Registrant shall provide certain indemnification of its trustees and officers. In accordance with Section 17(h) of the Investment Company Act of 1940, as amended, that provision shall not protect any person against any liability to the Registrant or its shareholders to which he would otherwise be subject by reason of willful misfeasance, bad faith, gross negligence or reckless disregard of the duties involved in the conduct of his office.

Insofar as indemnification for liabilities arising under the Securities Act of 1933, as amended (the “Securities Act”) may be permitted to trustees, officers and controlling persons of the Registrant pursuant to the foregoing provisions, or otherwise, the Registrant has been advised that in the opinion of the Securities and Exchange Commission such indemnification is against public policy as expressed in the Securities Act and is, therefore, unenforceable. In the event that a claim for indemnification against such liabilities (other than the payment by the Registrant of expenses incurred or paid by a trustee, officer or controlling person of the Registrant in the successful defense of any action, suit or proceeding) is asserted by such trustee, officer or controlling person in connection with the securities being registered, the Registrant will, unless in the opinion of its counsel the matter has been settled by controlling precedent, submit to a court of appropriate jurisdiction the question whether such indemnification by it is against public policy as expressed in the Securities Act and will be governed by the final adjudication of such issue.

The Registrant has entered into Indemnification Agreements with each of the independent trustees which provide that the Registrant shall indemnify and advance expenses to the independent trustees as provided in the Indemnification Agreements and otherwise to the fullest extent permitted by applicable law. The Registrant will indemnify the independent trustees from and against any and all judgments, penalties, fines and amounts paid in settlement, and all expenses actually and reasonably incurred by the independent trustees in connection with a proceeding to which he or she is a party to by reason of his or her position as an independent trustee. The Registrant will not indemnify the independent trustees for monetary settlements or judgments relating to insider trading, disgorgements of profits pursuant to Section 16(b) of the Securities Exchange Act of 1934, as amended, or any liability to the Trust or its shareholders with respect to a final adjudication that an action or omission by an independent trustee was committed in bad faith, involved deliberate dishonesty or that the trustee engaged in willful misfeasance, bad faith, gross negligence or reckless disregard of his or her duties.

The Registrant, its trustees and officers, its investment adviser and persons affiliated with them are insured under policies of insurance maintained by Registrant and its investment adviser, respectively, within the limits and subject to the limitations of the policies, against certain expenses in connection with the defense of actions, suits or proceedings, and certain liabilities that might be imposed as a result of such actions, suits or proceedings, to which they are parties by reason of being or having been such trustees or officers. The policies expressly excludes coverage for any trustee or officer whose personal dishonesty, fraudulent breach of trust, lack of good faith, or intention to deceive or defraud has been finally adjudicated or may be established or who willfully fails to act prudently.

Item 31. Business and Other Connections of Investment Adviser

The information in the prospectuses under the caption “Management of the Fund - Primary Service Providers - The Investment Manager” is incorporated by reference. Columbia Wanger Asset Management, LLC (“CWAM”) was not at any time during the past two years engaged in any other business, profession, vocation or employment of a substantial nature either for its own account or in the capacity of director, officer, employee, partner or trustee.

Item 32. Principal Underwriters

(a) Columbia Management Investment Distributors, Inc. (“CMID”), an affiliate of Columbia Management Investment Advisers, LLC (“Columbia Management”), is the Registrant’s principal underwriter. CMID also acts in such capacity for each series of Columbia Funds Series Trust, Columbia Funds Series Trust I, Columbia Fund Series Trust II, Columbia Funds Variable Insurance Trust, Columbia Funds Variable Series Trust II and Wanger Advisors Trust and certain other open-end investment companies in the Columbia Family of Funds (the mutual fund complex that is comprised of the open-end investment companies advised by Columbia Management or its affiliates and principally underwritten by CMID).

(b) The tables below lists each director or officer of the principal underwriter named in the answer to Item 25.

Name and Principal Business Address*	Position and Offices with Principal Underwriter	Positions and Offices with the Registrant
William F. Truscott	Chief Executive Officer and Director	None
Scott E. Couto	President	None
Michael S. Mattox	Chief Financial Officer	None
Michael E. DeFao	Vice President, Chief Legal Officer and Assistant Secretary	None
Stephen O. Buff	Vice President, Chief Compliance Officer	None
James Bumpus	Vice President and Head of Intermediary Markets	None
Thomas A. Jones	Vice President and Head of Strategic Relations	None
Gary Rawdon	Vice President – Sales Governance and Administration	None
Leslie A. Walstrom	Global Head of Marketing	None
Daniel J. Beckman	Vice President and Head of North America Marketing Product and Director	Co-President and Principal Executive Officer
Marc Zeitoun	Chief Operating Officer, North American Distribution	None
Wendy B. Mahling	Secretary	None
Amy L. Hackbarth	Vice President and Assistant Secretary	None
Mark D. Kaplan	Vice President and Assistant Secretary	None
Nancy W. LeDonne	Vice President and Assistant Secretary	None
Ryan C. Larrenaga	Vice President and Assistant Secretary	Assistant Secretary
Joseph L. D’Alessandro	Vice President and Assistant Secretary	None
Christopher O. Petersen	Vice President and Assistant Secretary	None
Shweta J. Jhanji	Vice President and Treasurer	None
Michael Tempesta	Anti-Money Laundering Officer and Identity Theft Prevention Officer	None
Kevin Wasp	Ombudsman	None
Kristin Weisser	Conflicts Officer	None

* The principal business address of Columbia Management Investment Distributors, Inc. is 290 Congress Street, Boston, MA 02210.

(c) Not applicable.

Item 33. Location of Accounts and Records

Stephen Kusmierczak, Co-President

Dan Beckman, Co-President Columbia Acorn Trust

71 S. Wacker Drive, Suite 2500

Chicago, IL 60606

Certain records, including records relating to the Registrant’s shareholders and the physical possession of its securities, may be maintained at the main office of Registrant’s transfer agent, Columbia Management Investment Services Corp., located at 290 Congress Street, Boston, MA. 02210 or custodian, JPMorgan Chase Bank, N.A., located at 1 Chase Manhattan Plaza, New York, NY 10005.

Certain information on the above-referenced physical possession of accounts, books and other documents is also included in the Registrant’s filing on Form N-CEN filed with the Securities and Exchange Commission on March 15, 2022.

Item 34. Management Services

Not applicable.

Item 35. Undertakings

Not applicable.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933 and the Investment Company Act of 1940, the Registrant certifies that it meets all the requirements for effectiveness of this post-effective amendment pursuant to Rule 485(b) under the Securities Act of 1933 and has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized, in the City of Chicago and State of Illinois on April 27, 2022.

COLUMBIA ACORN TRUST
By:	/S/    DANIEL BECKMAN
	Daniel Beckman, Co-President

Pursuant to the requirements of the Securities Act of 1933, this amendment to the registration statement has been signed below by the following persons in the capacities and on the dates indicated.

Name	Title		Date
/S/    MAUREEN M. CULHANE	Trustee	)
Maureen M. Culhane		)
		)
/S/    MARGARET M. EISEN	Trustee	)
Margaret M. Eisen		)
		)
/S/    JOHN C. HEATON	Trustee	)
John C. Heaton		)
		)
/S/    DIANNE F. LOB	Trustee	)
Dianne F. Lob		)
		)
/S/    CHARLES R. PHILLIPS	Trustee	)
Charles R. Phillips		)
		)
/S/    DAVID J. RUDIS	Trustee and Chair	)	April 27, 2022
David J. Rudis		)
		)
/S/    STEPHEN KUSMIERCZAK	Co-President	)
Stephen Kusmierczak		)
		)
/S/    DANIEL BECKMAN	Co-President and Principal Executive	)
Daniel Beckman	Officer	)
		)
/S/    MICHAEL G. CLARKE	Treasurer and Principal Financial	)
Michael G. Clarke	Officer	)
		)

Exhibits Related to Item 28 of Part C

Exhibit Number	Exhibit
d.5	Investment Advisory Fee Reduction Agreement between Columbia Acorn Trust, on behalf of Columbia Acorn USA, and Columbia Wanger Asset Management, LLC dated May 1, 2022.
h.4	Fee Waiver/Expense Reimbursement Agreement between Columbia Acorn Trust and Columbia Wanger Asset Management, LLC, relating to Columbia Acorn International, dated May 1, 2022.
h.5	Fee Waiver/Expense Reimbursement Agreement between Columbia Acorn Trust and Columbia Wanger Asset Management, LLC, relating to Columbia Acorn USA, dated May 1, 2021.
h.6	Fee Waiver/Expense Reimbursement Agreement between Columbia Acorn Trust and Columbia Wanger Asset Management, LLC, relating to Columbia Thermostat Fund, dated May 1, 2022.
h.7	Fee Waiver/Expense Reimbursement Agreement between Columbia Acorn Trust and Columbia Wanger Asset Management, LLC, relating to Columbia Acorn Fund, dated May 1, 2022.
h.8	Fee Waiver/Expense Reimbursement Agreement between Columbia Acorn Trust and Columbia Wanger Asset Management, LLC, relating to Columbia Acorn European Fund, dated May 1, 2022.
h.10	Fee Waiver/Expense Reimbursement Agreement, relating to Columbia Acorn International Select, between Columbia Acorn Trust and Columbia Wanger Asset Management, LLC dated May 1, 2022.
h.11	Transfer Agent Fee Waiver Agreement between Columbia Acorn Trust and Columbia Management Investment Services Corp., dated May 1, 2022.
h.16	Amended and Restated Credit Agreement as of October 28, 2021.
i.	Opinion letter and written consent of Perkins Coie LLP relating to the series of Columbia Acorn Trust.
j.	Consent of independent registered accounting firm.
p.1	Columbia Threadneedle Investments Global Personal Account Dealing and Code of Ethics, effective December 2021.

Exhibits Related to XBRL Interactive Data Files

Exhibit No.	Description
EX-101.INS	XBRL Instance Document
EX-101.SCH	XBRL Taxonomy Extension Schema Document
EX-101.CAL XBRL	Taxonomy Extension Calculation Linkbase
EX-101.DEF XBRL	Taxonomy Extension Definition Linkbase
EX-101.LAB XBRL	Taxonomy Extension Labels Linkbase
EX-101.PRE XBRL	Taxonomy Extension Presentation Linkbase

EX-99.(D)(5)

INVESTMENT ADVISORY FEE REDUCTION AGREEMENT

This Investment Advisory Fee Reduction Agreement (the “Fee Reduction Agreement”) dated as of May 1, 2022 is by and between Columbia Acorn Trust (the “Trust”), on behalf of its series Columbia Acorn USA (the “Fund”), and Columbia Wanger Asset Management, LLC, the Fund’s investment adviser (“CWAM”).

WHEREAS, the Trust and CWAM have entered into an Investment Advisory Agreement dated May 27, 2010 (the “Advisory Agreement”) that sets forth the respective rights and obligations of the Trust and CWAM in connection with CWAM’s provision of investment advisory services to the Fund;

WHEREAS, in payment for the investment advisory services rendered by CWAM pursuant to Schedule B of the Advisory Agreement, the Trust, on behalf of the Fund, pays CWAM fees accrued daily and paid monthly at the annual rate of (i) 0.940% on the Fund’s net assets up to $200 million, (ii) 0.890% on the Fund’s net assets from $200 million to $500 million, (iii) 0.840% on the Fund’s net assets from $500 million to $2 billion, (iv) 0.800% on the Fund’s net assets from $2 billion to $3 billion and (v) 0.700% on the Fund’s net assets over $3 billion. (the “Advisory Fee”);

WHEREAS, the Trust and CWAM desire to permanently reduce the Advisory Fee as set forth herein; and

WHEREAS, CWAM represents that the quality and quantity of its services provided under the Advisory Agreement will not be affected by this Fee Reduction Agreement and that its obligations under the Advisory Agreement will remain unchanged in all respects.

NOW THEREFORE, the Trust and CWAM hereby agree that the Advisory Fee shall be reduced such that under the Advisory Agreement the Trust, on behalf of the Fund, pays CWAM fees accrued daily and paid monthly as follows:

• 0.740% of the Fund’s net assets up to $700 million

• 0.690% of the Fund’s net assets from $700 million to $2 billion

• 0.640% of the Fund’s net assets from $2 billion to $6 billion

• 0.630% on the Fund’s net assets over $6 billion

This undertaking shall be binding upon any successors and assignees of CWAM, and may only be modified or amended with approval from the Trust and CWAM, except that any future increases in the contractual fee rates under this Fee Reduction Agreement must be approved by Board of Trustees of the Trust and the shareholders of the Fund as and to the extent required by the Investment Company Act of 1940. A copy of the Trust’s Agreement and Declaration of Trust, as amended, is on file with the Secretary of the Commonwealth of Massachusetts, and notice is hereby given that this instrument is executed on behalf of the Trust by its officers as officers and not individually. All obligations of the Trust hereunder shall be binding only upon the assets of the Fund and shall not be binding upon any trustee, officer, employee, agent or shareholder of the Trust. Neither the authorization of any action by the trustees or shareholders of the Trust, nor the execution of this Fee Reduction Agreement on behalf of the Trust, shall impose any liability upon any trustee, officer or shareholder of the Trust.

This Fee Reduction Agreement shall be attached to and made a part of the Advisory Agreement. The Advisory Agreement shall continue in full force and effect as modified hereby.

[Remainder of Page Intentionally Blank]

IN WITNESS THEREOF, the parties hereto have executed this Fee Reduction Agreement as of the day and year first written above.

COLUMBIA ACORN TRUST,
on behalf of its series Columbia Acorn USA
By:	/s/ Daniel J. Beckman
	Name:  Daniel J. Beckman
	Title:  Co-President

COLUMBIA WANGER ASSET MANAGEMENT, LLC

By:	/s/ Michael G. Clarke
	Name:  Michael G. Clarke
	Title:  Chief Financial Officer

2

EX-99.(H)(4)

COLUMBIA WANGER ASSET MANAGEMENT, LLC

71 S. Wacker Drive

Suite 2500

Chicago, IL 60606

May 1, 2022

Columbia Acorn Trust

71 S. Wacker Drive

Suite 2500

Chicago, Illinois 60606

Ladies and Gentlemen:

Columbia Wanger Asset Management, LLC (“CWAM”) hereby contractually undertakes as of the date hereof with respect to Columbia Acorn International (the “Fund”), a series of Columbia Acorn Trust (the “Trust”), to waive fees and reimburse certain expenses of the Fund, through April 30, 2023, such that total Fund ordinary operating expenses (excluding transaction costs and certain other investment-related expenses, and interest and fees on borrowings and expenses associated with the Fund’s investment in other investment companies, if any) do not exceed the annual rates of:

• 1.23% of the Fund’s average daily net assets attributable to Class A shares;

• 0.98% of the Fund’s average daily net assets attributable to Adviser Class shares;

• 1.98% of the Fund’s average daily net assets attributable to Class C shares;

• 0.98% of the Fund’s average daily net assets attributable to Institutional Class shares;

• 0.92% of the Fund’s average daily net assets attributable to Institutional 2 Class shares;

• 0.88% of the Fund’s average daily net assets attributable to Institutional 3 Class shares; and

• 1.48% of the Fund’s average daily net assets attributable to Class R shares.

This agreement may not be modified or terminated without the approval of the Fund’s Board of Trustees and CWAM.

This undertaking shall be binding upon any successors and assignees of CWAM.

Very truly yours,
COLUMBIA WANGER ASSET MANAGEMENT, LLC
By:	/s/ Michael G. Clarke
	Name:  Michael G. Clarke
	Title:  Chief Financial Officer

Agreed and accepted by

COLUMBIA ACORN TRUST, on behalf of its series Columbia Acorn International

By:	/s/ Daniel J. Beckman
	Name:  Daniel J. Beckman
	Title:  Co-President

EX-99.(H)(5)

COLUMBIA WANGER ASSET MANAGEMENT, LLC

71 S. Wacker Drive

Suite 2500

Chicago, IL 60606

May 1, 2022

Columbia Acorn Trust

71 S. Wacker Drive

Suite 2500

Chicago, Illinois 60606

Ladies and Gentlemen:

Columbia Wanger Asset Management, LLC (“CWAM”) hereby contractually undertakes as of the date hereof with respect to Columbia Acorn USA (the “Fund”), a series of Columbia Acorn Trust (the “Trust”), to waive fees and reimburse certain expenses of the Fund, through April 30, 2023, such that total Fund ordinary operating expenses (excluding transaction costs and certain other investment-related expenses, and interest and fees on borrowings and expenses associated with the Fund’s investment in other investment companies, if any) do not exceed the annual rates of:

• 1.08% of the Fund’s average daily net assets attributable to Class A shares;

• 0.83% of the Fund’s average daily net assets attributable to Adviser Class shares;

• 1.83% of the Fund’s average daily net assets attributable to Class C shares;

• 0.83% of the Fund’s average daily net assets attributable to Institutional Class shares;

• 0.81% of the Fund’s average daily net assets attributable to Institutional 2 Class shares; and

• 0.76% of the Fund’s average daily net assets attributable to Institutional 3 Class shares.

This agreement may not be modified or terminated without the approval of the Fund’s Board of Trustees and CWAM.

This undertaking shall be binding upon any successors and assignees of CWAM.

Very truly yours,
COLUMBIA WANGER ASSET MANAGEMENT, LLC
By:	/s/ Michael G. Clarke
	Name:  Michael G. Clarke
	Title:  Chief Financial Officer

Agreed and accepted by

COLUMBIA ACORN TRUST, on behalf of its series Columbia Acorn USA

By:	/s/ Daniel J. Beckman
	Name:  Daniel J. Beckman
	Title:  Co-President

EX-99.(H)(6)

COLUMBIA WANGER ASSET MANAGEMENT, LLC

71 S. Wacker Drive

Suite 2500

Chicago, IL 60606

May 1, 2022

Columbia Acorn Trust

71 S. Wacker Drive

Suite 2500

Chicago, Illinois 60606

Ladies and Gentlemen:

Columbia Wanger Asset Management, LLC (“CWAM”) hereby contractually undertakes as of the date hereof with respect to Columbia Thermostat Fund, a series of Columbia Acorn Trust (the “Fund”), to waive fees and reimburse certain expenses of the Fund, through April 30, 2023 such that total Fund ordinary operating expenses (excluding transaction costs and certain other investment-related expenses, interest and fees on borrowings and expenses associated with the Fund’s investment in other investment companies) do not exceed the annual rates of:

• 0.50% of the Fund’s average daily net assets attributable to Class A shares;

• 0.25% of the Fund’s average daily net assets attributable to Adviser Class shares;

• 1.25% of the Fund’s average daily net assets attributable to Class C shares;

• 0.25% of the Fund’s average daily net assets attributable to Institutional Class shares;

• 0.20% of the Fund’s average daily net assets attributable to Institutional 2 Class shares; and

• 0.16% of the Fund’s average daily net assets attributable to Institutional 3 Class shares.

This agreement may not be modified or terminated without the approval of the Fund’s Board of Trustees and CWAM. This undertaking shall be binding upon any successors and assignees of CWAM.

Very truly yours,
COLUMBIA WANGER ASSET MANAGEMENT, LLC
By:	/s/ Michael G. Clarke
	Name:  Michael G. Clarke
	Title:  Chief Financial Officer

Agreed and accepted by

COLUMBIA ACORN TRUST, on behalf of its series Columbia Thermostat Fund

By:	/s/ Daniel J. Beckman
	Name:  Daniel J. Beckman
	Title:  Co-President

EX-99.(H)(7)

COLUMBIA WANGER ASSET MANAGEMENT, LLC

71 S. Wacker Drive

Suite 2500

Chicago, IL 60606

May 1, 2022

Columbia Acorn Trust

71 S. Wacker Drive

Suite 2500

Chicago, Illinois 60606

Ladies and Gentlemen:

Columbia Wanger Asset Management, LLC (“CWAM”) hereby contractually undertakes as of the date hereof with respect to Columbia Acorn Fund (the “Fund”), a series of Columbia Acorn Trust (the “Trust”), to waive fees and reimburse certain expenses of the Fund, through April 30, 2023, such that total Fund ordinary operating expenses (excluding transaction costs and certain other investment-related expenses, and interest and fees on borrowings and expenses associated with the Fund’s investment in other investment companies, if any) do not exceed the annual rates of:

• 1.11% of the Fund’s average daily net assets attributable to Class A shares;

• 0.86% of the Fund’s average daily net assets attributable to Class Adv shares;

• 1.86% of the Fund’s average daily net assets attributable to Class C shares;

• 0.86% of the Fund’s average daily net assets attributable to Institutional Class shares;

• 0.84% of the Fund’s average daily net assets attributable to Institutional 2 Class shares; and

• 0.79% of the Fund’s average daily net assets attributable to Institutional 3 Class shares.

This agreement may not be modified or terminated without the approval of the Fund’s Board of Trustees and CWAM.

This undertaking shall be binding upon any successors and assignees of CWAM.

Very truly yours,
COLUMBIA WANGER ASSET MANAGEMENT, LLC
By:	/s/ Michael G. Clarke
	Name:  Michael G. Clarke
	Title:  Chief Financial Officer

Agreed and accepted by

COLUMBIA ACORN TRUST, on behalf of its series Columbia Acorn Fund

By:	/s/ Daniel J. Beckman
	Name:  Daniel J. Beckman
	Title:  Co-President

EX-99.(H)(8)

COLUMBIA WANGER ASSET MANAGEMENT, LLC

71 S. Wacker Drive

Suite 2500

Chicago, IL 60606

May 1, 2022

Columbia Acorn Trust

71 S. Wacker Drive

Suite 2500

Chicago, Illinois 60606

Ladies and Gentlemen:

Columbia Wanger Asset Management, LLC (“CWAM”) hereby contractually undertakes as of the date hereof with respect to Columbia Acorn European Fund (the “Fund”), a series of Columbia Acorn Trust (the “Trust”), to waive fees and reimburse certain expenses of the Fund, through April 30, 2023, such that total Fund ordinary operating expenses (excluding transaction costs and certain other investment-related expenses, and interest and fees on borrowings and expenses associated with the Fund’s investment in other investment companies, if any) do not exceed the annual rates of:

• 1.45% of the Fund’s average daily net assets attributable to Class A shares;

• 1.20% of the Fund’s average daily net assets attributable to Adviser Class shares;

• 2.20% of the Fund’s average daily net assets attributable to Class C shares;

• 1.20% of the Fund’s average daily net assets attributable to Institutional Class shares;

• 1.14% of the Fund’s average daily net assets attributable to Institutional 2 Class shares; and

• 1.11% of the Fund’s average daily net assets attributable to Institutional 3 Class shares.

This agreement may not be modified or terminated without the approval of the Fund’s Board of Trustees and CWAM.

This undertaking shall be binding upon any successors and assignees of CWAM.

Very truly yours,
COLUMBIA WANGER ASSET MANAGEMENT, LLC
By:	/s/ Michael G. Clarke
	Name:  Michael G. Clarke
	Title:  Chief Financial Officer

Agreed and accepted by

COLUMBIA ACORN TRUST, on behalf of its series Columbia Acorn European Fund

By:	/s/ Daniel J. Beckman
	Name:  Daniel J. Beckman
	Title:  Co-President

EX-99.(H)(10)

COLUMBIA WANGER ASSET MANAGEMENT, LLC

71 S. Wacker Drive

Suite 2500

Chicago, IL 60606

May 1, 2022

Columbia Acorn Trust

71 S. Wacker Drive

Suite 2500

Chicago, Illinois 60606

Ladies and Gentlemen:

This agreement amends and restates that certain Fee Waiver and Expense Reimbursement Agreement dated as of July 1, 2016 (the “2016 Agreement”), as amended, between Columbia Wanger Asset Management, LLC (“CWAM”) and Columbia Acorn Trust (the “Trust”), on behalf of its series Columbia Acorn International Select (the “Fund”), and amends and restates that certain Fee Waiver and Expense Reimbursement Agreement dated as of May 1, 2021 between CWAM and the Trust on behalf of the Fund.

CWAM hereby contractually undertakes as of the date hereof to waive fees and reimburse certain expenses of the Fund so that the ordinary operating expenses (excluding transaction costs and certain other investment-related expenses, interest and fees on borrowings and expenses associated with the Fund’s investment in other investment companies, if any) of each share class of the Fund do not exceed the annual rates set forth herein (each such annual rate an “Expense Cap”).

The Expense Cap for Institutional Class shares shall reflect the one-time 0.15% reduction in the total expense ratio for Institutional Class shares (from 1.30% to 1.15%) effected in the 2016 Agreement and shall be fixed at 1.15%. The Expense Cap for each of the Fund’s other share classes may fluctuate up or down based on certain expense differentials between Institutional Class shares and the Fund’s other share classes.

From May 1, 2022 through April 30, 2023, the Expense Cap is reduced such that the Expense Cap for each of the Fund’s share classes is: 1.24% for Class A shares; 0.99% for Adviser Class shares; 1.99% for Class C shares; 0.99% for Institutional Class shares; 0.89% for Institutional 2 Class shares; and 0.84% for Institutional 3 Class shares.

Except with respect to the annual restatement of the Expense Cap for each of the Fund’s share classes other than Institutional Class, this agreement may not be modified or terminated except by a vote of the Board of Trustees of the Trust and by a separate vote of a majority of the independent trustees of the Trust. This undertaking shall be binding upon any successors and assignees of CWAM.

Very truly yours,
COLUMBIA WANGER ASSET MANAGEMENT, LLC
By:	/s/ Michael G. Clarke
	Name:  Michael G. Clarke
	Title:  Chief Financial Officer

Agreed and accepted by

COLUMBIA ACORN TRUST, on behalf of its series Columbia Acorn International Select

By:	/s/ Daniel J. Beckman
	Name:  Daniel J. Beckman
	Title:  Co-President

EX-99.(H)(11)

COLUMBIA MANAGEMENT INVESTMENT SERVICES CORP.

290 Congress Street

Boston, MA 02210

Columbia Acorn Trust

71 S. Wacker Drive

Suite 2500

Chicago, Illinois 60606

May 1, 2022

Ladies and Gentlemen:

Columbia Management Investment Services Corp. (“CMIS”), hereby contractually undertakes as of the date hereof to waive a portion of the transfer agent and sub-transfer agency fees (together, “Combined TA Fees”) that would otherwise be payable to CMIS under the Transfer, Dividend Disbursing and Shareholders’ Servicing Agreement dated as of May 1, 2012 between the Columbia Acorn Trust (the “Trust,” and each series thereof a “Fund,” and together the “Funds”), on behalf of the Funds, and CMIS (the “Transfer Agent Agreement”) and the Side Letter Agreement between the Trust and CMIS dated as of July 1, 2017 relating to the Transfer Agent Agreement, such that through April 30, 2023, the annual Combined TA Fees paid by:

(a) Columbia Acorn International shall not exceed 0.04% of the average daily net assets of the Fund attributable to Class Institutional 2 Shares of the Fund and 0.00% of the average daily net assets of the Fund attributable to Class Institutional 3 Shares of the Fund;

(b) Columbia Acorn USA shall not exceed 0.08% of the average daily net assets of the Fund attributable to each share class of the Fund other than Class Institutional 2 and Class Institutional 3; and

(c) Columbia Acorn European Fund shall not exceed 0.03% of the average daily net assets of the Fund attributable to Class Institutional 2 Shares of the Fund and 0.00% of the average daily net assets of the Fund attributable to Class Institutional 3 Shares of the Fund.

This agreement may not be modified or terminated without the approval of the Fund’s Board of Trustees. This undertaking shall be binding upon any successors and assignees of CMIS.

Very truly yours,
COLUMBIA MANAGEMENT INVESTMENT SERVICES, CORP.
By:	/s/ Christie M. Wiley
	Name: Christie M. Wiley
	Title: Vice President

Agreed and accepted by

COLUMBIA ACORN TRUST

By:	/s/ Daniel J. Beckman
	Name: Daniel J. Beckman
	Title: President

EX-99.(H)(16)

EXECUTION VERSION

COLUMBIA FUNDS

$950,000,000

AMENDED AND RESTATED CREDIT AGREEMENT

Dated as of October 28, 2021

among

THE FUNDS LISTED FROM TIME TO TIME

ON SCHEDULE I HERETO,

VARIOUS BANKS,

JPMORGAN CHASE BANK, N.A.,

as Administrative Agent,

JPMORGAN CHASE BANK, N.A.,

CITIBANK, N.A. and

WELLS FARGO BANK, N.A., as

Joint Lead Arrangers and Joint Bookrunners, and

CITIBANK, N.A.,

as Syndication Agent

Table of Contents

		Page
SECTION 1.	DEFINITIONS		1
1.1	Defined Terms		1
1.2	Other Definitional Provisions		17
1.3	Assumptions Regarding Structure		17
1.4	Interest Rates		18
SECTION 2.	AMOUNT AND TERMS OF COMMITMENTS		18
2.1	Commitments		18
2.2	Procedure for Borrowing		19
2.3	Fees		20
2.4	Termination and Reduction of Commitments		20
2.5	Repayment of Loans; Evidence of Debt		21
2.6	Optional and Mandatory Prepayments		22
2.7	Interest Rates and Payment Dates		22
2.8	Computation of Interest and Fees		23
2.9	Pro Rata Treatment and Payments		23
2.10	Requirements of Law		24
2.11	Taxes		26
2.12	Change of Lending Office; Replacement of Lender		28
2.13	Swing Line Commitment		29
2.14	Procedure for Swing Line Borrowing		29
2.15	Refunding of Swing Line Loans		30
2.16	Designation of Additional Borrowers; Amendments to Schedule I		32
2.17	Interfund Lending		32
2.18	Defaulting Lender		34
SECTION 3.	REPRESENTATIONS AND WARRANTIES		35
3.1	Financial Condition		35
3.2	No Change		35
3.3	Existence; Compliance with Law		36
3.4	Power; Authorization; Enforceable Obligations		36
3.5	No Legal Bar		36
3.6	No Material Litigation		37
3.7	No Default		37
3.8	Ownership of Property; Liens		37
3.9	No Burdensome Restrictions		37
3.10	Taxes		37
3.11	Federal Regulations		37
3.12	ERISA		37
3.13	Certain Regulations		37
3.14	Subsidiaries		38
3.15	Registration of the Fund		38

3.16	Offering in Compliance with Securities Laws	38
3.17	Investment Policies	38
3.18	Permission to Borrow	38
3.19	Accuracy of Information; Electronic Information	38
3.20	Affiliated Persons	39
3.21	Anti-Corruption Laws and Sanctions	39
3.22	EEA Financial Institutions	39
SECTION 4.	CONDITIONS PRECEDENT	40
4.1	Conditions to Closing	40
4.2	Conditions to Each Loan	41
4.3	Lender Deliverables	42
SECTION 5.	AFFIRMATIVE COVENANTS	42
5.1	Financial Statements	43
5.2	Certificates; Other Information	44
5.3	Payment of Obligations	44
5.4	Conduct of Business and Maintenance of Existence	44
5.5	Maintenance of Property; Insurance	45
5.6	Inspection of Property; Books and Records; Discussions	45
5.7	Notices	45
5.8	Purpose of Loans	46
5.9	Payment of Taxes	46
SECTION 6.	NEGATIVE COVENANTS	47
6.1	Financial Condition Covenant	47
6.2	Limitation on Indebtedness; Derivatives	47
6.3	Limitation on Liens	48
6.4	Limitation on Guarantee Obligations	48
6.5	Limitation on Fundamental Changes	48
6.6	Limitation on Distributions	48
6.7	Limitation on Investments, Loans and Advances	49
6.8	Limitation on Transactions with Affiliates	49
6.9	Limitation on Negative Pledge Clauses	49
6.10	Limitation on Changes to Investment Policies	49
6.11	Cayman Parent Borrower Activities	49
6.12	Cayman Parent Borrower Sale of Assets, Etc	49
6.13	Prohibited Use of Proceeds	50
SECTION 7.	EVENTS OF DEFAULT	50
SECTION 8.	THE ADMINISTRATIVE AGENT	53
8.1	Authorization and Action	53
8.2	Administrative Agent’s Reliance, Limitation of Liabilities, Etc.	56
8.3	Posting of Communications	57
8.4	The Administrative Agent Individually	58
8.5	Successor Administrative Agent	59

ii

8.6	Acknowledgment of Lenders	60
8.7	Duties of Syndication Agents	62
SECTION 9.	MISCELLANEOUS	62
9.1	Amendments and Waivers	62
9.2	Notices	63
9.3	No Waiver; Cumulative Remedies	64
9.4	Survival of Representations and Warranties	64
9.5	Payment of Expenses and Taxes; Indemnification	64
9.6	Successors and Assigns; Participations and Assignments	66
9.7	Adjustments; Set-off	68
9.8	Counterparts	69
9.9	Severability	70
9.10	Waiver of Conflicts; Confidentiality	70
9.11	GOVERNING LAW	72
9.12	Submission To Jurisdiction; Waivers	72
9.13	Acknowledgments	72
9.14	WAIVERS OF JURY TRIAL	73
9.15	Non-Recourse	73
9.16	Integration	73
9.17	USA PATRIOT Act	73
9.18	Net Asset Value	74
9.19	Acknowledgement and Consent to Bail-In of Affected Financial Institutions	74
9.20	Mauritius Subsidiaries	74
9.21	No Fiduciary Duty, etc.	74

SCHEDULES:

Schedule I	Borrowers & Pro Rata Allocations
Schedule II	Commitments, Addresses, Etc.
Schedule III	Investment Management Agreements
Schedule IV	Custody Agreements
Schedule V	Prime Broker Agreements
Schedule 5.1	Web Addresses For Annual, Semi-Annual and Quarterly Reports
Schedule 9.20	Representations, Covenants and Events of Default Applicable to Borrowers with Mauritius Subsidiaries
EXHIBITS:
Exhibit 2.5(e)	Form of Note
Exhibit 2.16(a)	Form for Designation of New Borrowers
Exhibit 9.6(c)	Form of Assignment and Acceptance

iii

AMENDED AND RESTATED CREDIT AGREEMENT, dated as of October 28, 2021 (as amended, restated, supplemented or otherwise modified from time to time, this “Agreement”) among (i) the trusts listed on Schedule I (the “Registrants”), each of which is executing this Agreement on behalf of its respective underlying series set forth beneath such Registrant’s name on Schedule I (each such series, individually, a “Borrower” or “Fund” and, collectively, the “Borrowers” or “Funds”), (ii) the several banks and other financial institutions from time to time parties to this Agreement (the “Lenders”), and (iii) JPMORGAN CHASE BANK, N.A., a national banking association, as administrative agent for the Lenders hereunder

(in such capacity, the “Administrative Agent”);

W I T N E S E T H:

WHEREAS, each Registrant is an open-end registered investment company under the Investment Company Act of 1940 for which Columbia Management (as defined below) acts as an investment manager;

WHEREAS, each Borrower has requested the Lenders to make Loans (as defined below) severally and not jointly to each Borrower and to make available to it a credit facility for the purposes and on the terms and conditions set forth herein;

WHEREAS, each Lender acknowledges that each Borrower shall be liable hereunder only for the Loans made to such Borrower hereunder and interest thereon and for the fees and expenses associated therewith and as otherwise set forth herein, and that, notwithstanding anything to the contrary herein, each Borrower’s obligations hereunder are several and not joint;

WHEREAS, certain of the parties hereto entered into the Amended and Restated Credit Agreement dated as of December 1, 2020 (as amended, restated, terminated, replaced, supplemented or otherwise modified, the “Original Credit Agreement”);

WHEREAS, the parties hereto wish to amend and restate the Original Credit Agreement to incorporate terms provided herein;

NOW, THEREFORE, in consideration of the premises and mutual covenants herein contained, the parties to this Agreement agree as follows:

SECTION 1. DEFINITIONS

1.1 Defined Terms. As used in this Agreement, the following terms shall have the following meanings:

“Administrative Agent”: JPMorgan Chase Bank, N.A., together with its permitted successors and assigns, as the administrative agent for the Lenders under this Agreement and the other Loan Documents.

“Affected Borrowers”: with respect to any Bank-Advisor, any Borrower with respect to which (i) such Bank-Advisor or any of its affiliates acts as an advisor or sub-advisor, (ii) such Bank-Advisor is prohibited from lending to by any Applicable Law or (iii) an extension of credit by such Bank-Advisor would subject such Bank-Advisor to lending limits under any Applicable Law (including Regulation W).

“Affected Financial Institution”: (a) any EEA Financial Institution or (b) any UK Financial Institution.

“Affiliate”: as to any Person, any other Person (other than a Subsidiary) which, directly or indirectly, is in control of, is controlled by, or is under common control with, such Person. For purposes of this definition, “control” of a Person means the power, directly or indirectly, either to (a) vote 10% or more of the securities having ordinary voting power for the election of directors of such Person or (b) direct or cause the direction of the management and policies of such Person, whether by contract or otherwise.

“Aggregate Commitment”: the total of all Commitments of all Lenders, as may be reduced from time to time in accordance with the terms of this Agreement. On the Closing Date, the Aggregate Commitment shall be equal to $950,000,000.

“Agreement”: as defined in the Preamble hereto.

“Ancillary Document”: as defined in Section 9.8(b).

“Anti-Corruption Laws”: all laws, rules, and regulations of any jurisdiction applicable to any Borrower or its Subsidiaries from time to time concerning or relating to money laundering, bribery or corruption, or any jurisdiction applicable to any Lender concerning or relating to money laundering.

“Applicable Law”: any law, treaty, rule or regulation or determination of an arbitrator or a court or other Governmental Authority, in each case applicable to or binding upon such Person or any of its property or to which such Person or any of its property is subject.

“Applicable Margin”: 1.00% per annum.

“Arranger”: JPMorgan Chase Bank, N.A. in its capacity as lead arranger hereunder.

“Asset Coverage Ratio”: with respect to any Borrower, the ratio which the value of the Total Assets of such Borrower less all liabilities and Indebtedness of such Borrower not represented by Senior Securities, bears to the aggregate amount of all Senior Securities representing Indebtedness of such Borrower. For the purposes of calculating the Asset Coverage Ratio, (i) the amount of any liability or Indebtedness deducted from Total Assets of such Borrower shall be equal to the greater of (x) the outstanding amount of such liability or Indebtedness and (y) the fair market value of all assets securing such liability or Indebtedness; (ii) the indebtedness incurred by any Borrower under any Interfund Lending shall be deemed to be a Senior Security for purposes of calculating the Asset Coverage Ratio as it applies to such Borrower; (iii) in order to ensure that Borrowers that are part of a fund-of-funds or master-feeder structure do not borrow against the same assets, for purposes of calculating the Asset Coverage

2

Ratio, if any Borrower invests in another Borrower, the value of such assets shall, as between both such Borrowers, only be counted once; (iv) in determining the numerator of said ratio and to the extent that the Investment Company Act does not already require the following deduction, the following shall be deducted: If the Borrower is the Cayman Parent Borrower, the value of (1) all assets belonging to the Cayman Designated Subsidiary and (2) such Borrower’s direct or indirect debt, equity or other interests or investments in the Cayman Designated Subsidiary; (v) indebtedness incurred by the Cayman Designated Subsidiary shall not be included in either the numerator or the denominator of said ratio in determining the Asset Coverage Ratio of the Cayman Parent Borrower; and (vi) if the Borrower is a Mauritius Parent Borrower, the assets and indebtedness of its Mauritius Designated Subsidiary will be included in calculating the Asset Coverage Ratio of such Mauritius Parent Borrower.

“Assignee”: as defined in Section 9.6(c).

“Available Commitment”: as to any Lender at any time, an amount equal to (a) the amount of such Lender’s Commitment less (b) the sum of (i) the aggregate principal amount of all Revolving Credit Loans to all Borrowers made by such Lender then outstanding and (ii) such Lender’s Swing Line Exposure at such time; collectively, as to all the Lenders, the “Available Commitments”.

“Bail-In Action”: the exercise of any Write-Down and Conversion Powers by the applicable Resolution Authority in respect of any liability of an Affected Financial Institution.

“Bail-In Legislation”: (a) with respect to any EEA Member Country implementing Article 55 of Directive 2014/59/EU of the European Parliament and of the Council of the European Union, the implementing law, regulation, rule or requirement for such EEA Member Country from time to time which is described in the EU Bail-In Legislation Schedule and (b) with respect to the United Kingdom, Part I of the United Kingdom Banking Act 2009 (as amended from time to time) and any other law, regulation or rule applicable in the United Kingdom relating to the resolution of unsound or failing banks, investment firms or other financial institutions or their affiliates (other than through liquidation, administration or other insolvency proceedings).

“Bank-Advisor”: each of JPMorgan Chase Bank, N.A., Morgan Stanley Bank, N.A., Bank of America, N.A., Wells Fargo Bank, National Association, The Bank of New York Mellon and any other Lender (i) prohibited by any Applicable Law from lending to one or more of the Borrowers or (ii) for whom an extension of credit by it to one or more Borrowers would subject such Bank-Advisor to lending limits under any Applicable Law (including Regulation W).

“Bankruptcy Event”: with respect to any Person, such Person becomes the subject of a bankruptcy or insolvency proceeding, or has had a receiver, conservator, trustee, administrator, custodian, assignee for the benefit of creditors or similar Person charged with the reorganization or liquidation of its business appointed for it, or, in the good faith determination of the Administrative Agent, has taken any action in furtherance of, or indicating its consent to, approval of, or acquiescence in, any such proceeding or appointment, provided that a Bankruptcy Event shall not result solely by virtue of any ownership interest, or the acquisition of any

3

ownership interest, in such Person by a Governmental Authority or instrumentality thereof, unless such ownership interest results in or provides such Person with immunity from the jurisdiction of courts within the United States or from the enforcement of judgments or writs of attachment on its assets or permits such Person (or such Governmental Authority or instrumentality) to reject, repudiate, disavow or disaffirm any contracts or agreements made by such Person.

“Benchmark Replacement Date”: the earliest to occur of the following events:

(1) in the case of clause (1) or (2) of the definition of “Benchmark Transition Event,” the later of (a) the date of the public statement or publication of information referenced therein and (b) the date on which the administrator of Daily Simple SOFR (or the published component used in the calculation thereof) permanently or indefinitely ceases to provide Daily Simple SOFR; or

(2) in the case of clause (3) of the definition of “Benchmark Transition Event,” the first date on which Daily Simple SOFR (or the published component used in the calculation thereof) has been determined and announced by the regulatory supervisor for the administrator of Daily Simple SOFR (or such component thereof) to be no longer representative; provided, that such non-representativeness will be determined by reference to the most recent statement or publication referenced in such clause (3) and even if Daily Simple SOFR (or such component thereof) continues to be provided on such date.

For the avoidance of doubt, if the event giving rise to the Benchmark Replacement Date occurs on the same day as, but earlier than, the Reference Time in respect of any determination, the Benchmark Replacement Date will be deemed to have occurred prior to the Reference Time for such determination.

“Benchmark Transition Event”: the occurrence of one or more of the following events:

(1) a public statement or publication of information by or on behalf of the administrator of Daily Simple SOFR (or the published component used in the calculation thereof) announcing that such administrator has ceased or will cease to provide Daily Simple SOFR (or such component thereof), permanently or indefinitely, provided that, at the time of such statement or publication, there is no successor administrator that will continue to provide Daily Simple SOFR (or such component thereof);

(2) a public statement or publication of information by the regulatory supervisor for the administrator of Daily Simple SOFR (or the published component used in the calculation thereof), the Federal Reserve Board, the NYFRB, an insolvency official with jurisdiction over the administrator for Daily Simple SOFR (or such component), a resolution authority with jurisdiction over the administrator for Daily Simple SOFR (or such component) or a court or an entity with similar insolvency or resolution authority over the administrator for Daily Simple SOFR (or such component), in each case, which states that the administrator of Daily Simple SOFR (or such component) has ceased or will cease to provide Daily Simple SOFR (or such component thereof) permanently or indefinitely; provided that, at the time of such statement or publication, there is no successor administrator that will continue to provide Daily Simple SOFR (or such component thereof); or

4

(3) a public statement or publication of information by the regulatory supervisor for the administrator of Daily Simple SOFR (or the published component used in the calculation thereof) announcing that Daily Simple SOFR (or such component thereof) are no longer, or as of a specified future date will no longer be, representative.

“Benchmark Unavailability Period”: the period (if any) (x) beginning at the time that a Benchmark Replacement Date pursuant to clauses (1) or (2) of that definition has occurred.

“Benefited Lender”: as defined in Section 9.7(a).

“Borrower” and “Borrowers”: as defined in the Preamble hereto.

“Borrowing Date”: any Business Day specified in a notice pursuant to Section 2.2 or 2.14 as a date on which a Registrant, on behalf of a series thereof that is a Borrower, requests the Lenders to make Loans hereunder.

“Business Day”: a day other than a Saturday, Sunday or other day on which commercial banks in New York City or Minneapolis, Minnesota are authorized or required by law to close.

“Cayman Designated Subsidiaries”: CCSF Offshore Fund, Ltd., a wholly-owned subsidiary of CCSF; ASMF Offshore Fund, Ltd. and ASGM Offshore Fund, Ltd., each of which is a wholly-owned subsidiary of MASF; CVPCSF Offshore Fund, Ltd., a wholly-owned subsidiary of CVPCSF; CMSAF1 Offshore Fund, Ltd., CMSAF2 Offshore Fund, Ltd. and CMSAF3 Offshore Fund, Ltd., each of which is a wholly-owned subsidiary of CMSAF.

“Cayman Parent Borrowers”: Columbia Commodity Strategy Fund (“CCSF”), Multi-Manager Alternative Strategies Fund (“MASF”), Columbia Variable Portfolio—Commodity Strategy Fund (“CVPCSF”) and Columbia Multi Strategy Alternatives Fund (“CMSAF”).

“Closing Date”: the date on which the conditions precedent set forth in Section 4.1 shall be satisfied and the Loan Documents are signed by the parties hereto and delivered to the offices of Pryor Cashman LLP at Seven Times Square, New York, New York 10036, which date shall be the date as of which this Agreement is dated.

“Code”: the Internal Revenue Code of 1986, as amended from time to time.

“Columbia Management”: Columbia Management Investment Advisers, LLC, a Minnesota limited liability company, or Columbia Wanger Asset Management, LLC, a Delaware limited liability company, as applicable.

“Commitment”: as to any Lender, the obligation of such Lender to make Loans to the Borrowers hereunder in an aggregate principal amount at any one time outstanding not to exceed the amount set forth opposite such Lender’s name on Schedule II, as such amount may be reduced pursuant to the terms hereof.

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“Commitment Fee”: as defined in Section 2.3.

“Commitment Fee Accrual Date”: each of (a) the last day of March, June, September and December of each year and (b) the Termination Date.

“Commitment Fee Payment Date”: (a) with respect to any Commitment Fee Accrual Date described in clause (a) of the definition thereof, the 15^th day after such Commitment Fee Accrual Date (or if such day is not a Business Day, the immediately following Business Day) and (b) with respect to any Commitment Fee Accrual Date described in clause (b) of the definition thereof, the Termination Date.

“Commitment Percentage”: as to any Lender at any time, the percentage which such Lender’s Commitment then constitutes of the aggregate Commitments of all Lenders; provided that when a Defaulting Lender shall exist, “Commitment Percentage” shall mean the percentage of the total Commitments (disregarding any Defaulting Lender’s Commitment) represented by such Lender’s Commitment. If the Commitments have terminated or expired, the Commitment Percentages shall be determined based upon the Commitments most recently in effect, giving effect to any assignments and to any Lender’s status as a Defaulting Lender at the time of determination.

“Commitment Period”: the period from and including the Closing Date to but not including, the Termination Date.

“Commonly Controlled Entity”: an entity, whether or not incorporated, which is under common control with any Borrower within the meaning of Section 4001 of ERISA or is part of a group which includes any Borrower and which is treated as a single employer under Section 414 of the Code.

“Confidential Information”: as defined in Section 9.10(b).

“Contractual Obligation”: as to any Person, any provision of any security issued by such Person or of any agreement, instrument or other undertaking to which such Person is a party or by which it or any of its property is bound.

“Credit Exposure”: with respect to any Lender at any time, the sum of the outstanding principal amount of such Lender’s Revolving Credit Loans and its Swing Line Exposure at such time.

“Credit Party”: the Administrative Agent, the Swing Line Lender and each other Lender.

“Custody Agreement”: as to each Fund, the related Custody Agreement(s) set forth in Schedule IV.

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“Daily Simple SOFR”: for any day, SOFR for such day. Any change in Daily Simple SOFR due to a change in SOFR shall be effective from and including the effective date of such change in SOFR in accordance with Section 2.8.

“Default”: any of the events specified in Section 7 (or in Section 3(a) of Schedule 9.20), which with notice, or lapse of time, or both, would constitute an Event of Default.

“Defaulting Lender”: any Lender that: (a) has failed, within three Business Days of the date required to be funded or paid, to (i) fund any portion of its Loans, (ii) fund any portion of its participations in Swing Line Loans or (iii) pay over to any Credit Party any other amount required to be paid by it hereunder, unless, in the case of clause (i) above, such Lender notifies the Administrative Agent in writing that such failure is the result of such Lender’s good faith determination that a condition precedent to funding (specifically identified and including the particular default, if any) has not been satisfied; (b) has notified the Borrower or any Credit Party in writing, or has made a public statement to the effect, that it does not intend or expect to comply with any of its funding obligations under this Agreement (unless such writing or public statement indicates that such position is based on such Lender’s good faith determination that a condition precedent (specifically identified and including the particular default, if any) to funding a loan under this Agreement cannot be satisfied) or generally under other agreements in which it commits to extend credit; (c) has failed, within three Business Days after request by a Credit Party, acting in good faith, to provide a certification in writing from an authorized officer of such Lender that it will comply with its obligations to fund prospective Loans and participations in then outstanding Swing Line Loans under this Agreement, provided that such Lender shall cease to be a Defaulting Lender pursuant to this clause (c) upon such Credit Party’s receipt of such certification in form and substance satisfactory to it and the Administrative Agent, (d) has become the subject of (A) a Bankruptcy Event or (B) a Bail-In Action, or (e) ceases to be a “Bank” (as defined in the 1940 Act).

“Designated Borrower”: each Borrower listed on Schedule Ia as a Designated Borrower.

“Designated Borrower Asset Coverage Ratio Percentage”: with respect to each Designated Borrower, the “Designated Percentage” set forth for such Designated Borrower on Schedule Ia, or, as to any additional Designated Borrower designated pursuant to Section 2.16, such other percentage as the Administrative Agent deems appropriate.

“Designated Percentage”: as defined in the definition of “Designated Borrower Asset Coverage Ratio Percentage.”

“Dollars” and “$”: lawful currency of the United States of America.

“EEA Financial Institution” means (a) any institution established in any EEA Member Country which is subject to the supervision of an EEA Resolution Authority, (b) any entity established in an EEA Member Country which is a parent of an institution described in clause (a) of this definition, or (c) any institution established in an EEA Member Country which is a subsidiary of an institution described in clauses (a) or (b) of this definition and is subject to consolidated supervision with its parent.

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“EEA Member Country” means any of the member states of the European Union, Iceland, Liechtenstein, and Norway.

“EEA Resolution Authority” means any public administrative authority or any Person entrusted with public administrative authority of any EEA Member Country (including any delegee) having responsibility for the resolution of any EEA Financial Institution.

“Electronic Signature” means an electronic sound, symbol, or process attached to, or associated with, a contract or other record and adopted by a Person with the intent to sign, authenticate or accept such contract or record.

“Eligible Lender”: an entity that is a “Bank” (as defined in the 1940 Act) and, except for a Bank-Advisor with respect to its respective Affected Borrowers, is not otherwise prohibited by any Applicable Law from lending to any of the Borrowers. Notwithstanding the foregoing, “Eligible Lender” shall not include any Borrower or any natural person or any Defaulting Lender.

“ERISA”: the Employee Retirement Income Security Act of 1974, as amended from time to time.

“EU Bail-In Legislation Schedule” means the EU Bail-In Legislation Schedule published by the Loan Market Association (or any successor Person), as in effect from time to time.

“Event of Default”: any of the events specified in Section 7 (or in Section 3(a) of Schedule 9.20), provided that any requirement for the giving of notice, the lapse of time, or both, or any other condition, has been satisfied.

“FATCA”: Sections 1471 through 1474 of the Code, as of the date of this Agreement (or any amended or successor version that is substantively comparable and not materially more onerous to comply with), or any Treasury regulations promulgated thereunder or official administrative interpretations thereof and any agreements entered into pursuant to Section 1471(b)(1) of the Code or any fiscal or regulatory legislation, rules or practices adopted pursuant to any intergovernmental agreement entered into in connection with the implementation of such Sections of the Code.

“Federal Funds Effective Rate”: for any day, the rate calculated by the NYFRB based on federal funds transactions by depository institutions (as determined in such manner as shall be set forth on the NYFRB’s Website from time to time) and published on the next succeeding Business Day by the NYFRB as the federal funds effective rate.

“Federal Funds Rate”: for any day, a rate per annum equal to the greatest of (a) the sum of (x) Daily Simple SOFR in effect on such day plus (y) 0.11448%, (b) the Federal Funds Effective Rate in effect on such day and (c) the Overnight Bank Funding Rate in effect on such day; provided, that during the continuance of a Benchmark Unavailability Period, the Federal Funds Rate shall be, for any day, a rate per annum equal to the sum of (1) the greater of (i) the Federal Funds Effective Rate in effect on such day and (ii) the Overnight Bank Funding Rate in effect on such day plus (2) 0.10%; provided, further that notwithstanding the rate calculated in accordance with the foregoing, at no time shall the Federal Funds Rate be less than 0% per annum.

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“Federal Reserve Board”: the Board of Governors of the Federal Reserve System of the United States of America.

“Financing Lease”: any lease of property, real or personal, the obligations of the lessee in respect of which are required in accordance with GAAP to be capitalized on a balance sheet of such lessee.

“Fund”: as defined in the Preamble hereto.

“GAAP”: generally accepted accounting principles in the United States of America in effect from time to time.

“Governmental Authority”: any nation or government, any state or other political subdivision thereof and any entity exercising executive, legislative, judicial, regulatory or administrative functions of or pertaining to government (including any supra-national bodies such as the European Union or the European Central Bank).

“Guarantee Obligation”: as to any Person (the “guaranteeing person”), any obligation of (a) the guaranteeing person or (b) another Person (including, without limitation, any bank under any letter of credit) to induce the creation of which the guaranteeing person has issued a reimbursement, counterindemnity or similar obligation, in either case guaranteeing or in effect guaranteeing any Indebtedness, leases, dividends or other obligations (the “primary obligations”) of any other third Person (the “primary obligor”) in any manner, whether directly or indirectly, including, without limitation, any obligation of the guaranteeing person, whether or not contingent, (i) to purchase any such primary obligation or any property constituting direct or indirect security therefor, (ii) to advance or supply funds (A) for the purchase or payment of any such primary obligation or (B) to maintain working capital or equity capital of the primary obligor or otherwise to maintain the net worth or solvency of the primary obligor, (iii) to purchase property, securities or services primarily for the purpose of assuring the owner of any such primary obligation of the ability of the primary obligor to make payment of such primary obligation or (iv) otherwise to assure or hold harmless the owner of any such primary obligation against loss in respect thereof; provided, however, that the term Guarantee Obligation shall not include endorsements of instruments for deposit or collection in the ordinary course of business. The amount of any Guarantee Obligation of any guaranteeing person shall be deemed to be the lower of (a) an amount equal to the stated or determinable amount of the primary obligation in respect of which such Guarantee Obligation is made and (b) the maximum amount for which such guaranteeing person may be liable pursuant to the terms of the instrument embodying such Guarantee Obligation, unless such primary obligation and the maximum amount for which such guaranteeing person may be liable are not stated or determinable, in which case the amount of such Guarantee Obligation shall be such guaranteeing person’s maximum reasonably anticipated liability in respect thereof as determined by such guaranteeing person in good faith.

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“Indebtedness”: of any Person at any date, (a) all indebtedness of such Person for borrowed money or for the deferred purchase price of property or services (other than current trade liabilities incurred in the ordinary course of business and payable in accordance with customary practices), (b) any other indebtedness of such Person which is evidenced by a note, bond, debenture or similar debt instrument, (c) any obligations of such Person under Financing Leases or Interest Rate Agreements or Swap Obligations as calculated daily on a marked-to-market basis in accordance with GAAP, (d) all obligations of such Person in respect of acceptances (as defined in Section 3-410 of the UCC) issued or created for the account of such Person, (e) all reimbursement obligations (contingent or otherwise) of such person arising out of any letters of credit, and (f) all liabilities secured by any Lien on any property owned by such Person even though such Person has not assumed or otherwise become liable for the payment thereof.

“Indemnitee”: as defined in Section 9.5(c)

“Interest Accrual Date”: with respect to each Loan (x) the last day of each calendar month in which such Loan is outstanding, (y) in connection with any prepayment, the date of such prepayment, and (z) the Maturity Date.

“Interest Payment Date”: with respect to any Loan and any Interest Accrual Date, the earlier of (x) the day five Business Days after such Interest Accrual Date for such Loan and (y) the Termination Date.

“Interest Rate Agreement”: any interest rate protection agreement, interest rate future, interest rate option, interest rate swap, interest rate cap or other interest rate hedge or arrangement under which a Borrower or Registrant, on behalf of a series thereof that is a Borrower, is a party or a beneficiary.

“Interfund Lending”: lending by a series advised by Columbia Management to one or more other series advised by Columbia Management, or borrowing by a series advised by Columbia Management from one or more other series advised by Columbia Management, in either case pursuant to an Interfund Lending Exemptive Order, or otherwise allowed by any Applicable Law.

“Interfund Lending Exemptive Order”: an exemptive order, including any amended or supplemental order, issued by the Securities and Exchange Commission authorizing Interfund Lending.

“Interfund Loan”: a loan to a Borrower pursuant to an Interfund Lending arrangement.

“Investment Management Agreement”: as to each Registrant on behalf of a series thereof that is a Borrower, the Investment Management Services Agreement set forth on Schedule III.

“Investment Policies”: as to each Borrower, the fundamental and non-fundamental policies, and related limits and restrictions, on investing by such Borrower set forth in the statement of additional information for such Borrower, as such statement of additional information may be amended or supplemented from time to time.

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“JP Morgan”: JPMorgan Chase Bank, N.A., a national banking association.

“Lender-Related Person”: as defined in Section 9.5(b).

“Lenders”: as defined in the Preamble hereto.

“Liabilities” means any losses, claims (including intraparty claims), demands, damages or liabilities of any kind.

“Lien”: any mortgage, pledge, hypothecation, assignment, deposit arrangement, encumbrance, lien (statutory or other), charge or other security interest or any preference, priority or other security agreement or preferential arrangement of any kind or nature whatsoever (including, without limitation, any conditional sale or other title retention agreement and any Financing Lease having substantially the same economic effect as any of the foregoing).

“Loan Documents”: this Agreement, the Notes and all other agreements, instruments, and other documents entered into in connection with the transactions contemplated by this Agreement, and all amendments and supplements thereto.

“Loans”: all loans made pursuant to this Agreement; individually, a “Loan”.

“Material Adverse Effect”: a material adverse effect on (a) the business, financial condition, operations or ability to timely perform any of its material obligations under the Loan Documents of a Registrant or a Borrower or (b) the legality, validity, binding nature or enforceability of the Loan Documents or the rights or remedies of the Administrative Agent or the Lenders hereunder or thereunder.

“Maturity Date”: as to each Loan, the date which is the earliest of (a) 60 days after the Borrowing Date for such Loan (or, with respect to a Swing Line Loan, seven days after the Borrowing date therefor), (b) the Termination Date and (c) the payment in full of such Loan.

“Mauritius Parent Borrowers”: Columbia India Consumer ETF (“EMC”).

“Mauritius Designated Subsidiaries”: EG Shares India Mauritius, a wholly-owned subsidiary of EMC. Each such Mauritius Designated Subsidiary is organized under the laws of the Republic of Mauritius.

“Moody’s”: Moody’s Investors Service, Inc.

“1940 Act”: the Investment Company Act of 1940, as amended, together with all rules and regulations promulgated from time to time thereunder.

“Non-Excluded Taxes”: as defined in Section 2.11.

“Non-Pro Rata Lender”: any Lender making a Non-Pro Rata Loan.

“Non-Pro Rata Loan”: (i) any Loan to an Affected Borrower or (ii) in the event any Loans are outstanding to one or more Affected Borrowers and, as a result thereof, not all of the Aggregate Commitment is available to be borrowed by one or more Unaffected Borrowers, any Loan made by the Bank-Advisor to such Unaffected Borrower.

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“Non-Recourse Person”: as defined in Section 9.15.

“Notes”: the collective reference to the Revolving Credit Notes; individually, a “Note”.

“NYFRB”: the Federal Reserve Bank of New York.

“NYFRB’s Website”: the website of the NYFRB at http://www.newyorkfed.org, or any successor source.

“Obligations”: all advances to, and debts, liabilities, obligations, covenants and duties of, the Borrowers arising under any Loan Document or otherwise with respect to any Loan, whether direct or indirect (including those acquired by assumption), absolute or contingent, due or to become due, now existing or hereafter arising and including interest and fees that accrue after the commencement by or against any Borrower or any Affiliate thereof of any proceeding under any debtor relief laws naming such Person as the debtor in such proceeding, regardless of whether such interest and fees are allowed or allowable claims in such proceeding. Without limiting the foregoing, the Obligations include (a) the obligation to pay principal, interest, charges, expenses, fees, indemnities and other amounts payable by the Borrowers under any Loan Document and (b) the obligation of the Borrowers to reimburse any amount in respect of any of the foregoing that the Administrative Agent or any Lender, in each case in its sole discretion, may elect to pay or advance on behalf of the Borrower.

“Other Lender”: any Lender other than a Bank-Advisor.

“Overnight Bank Funding Rate”: for any day, the rate comprised of both overnight federal funds and overnight eurodollar transactions by U.S.-managed banking offices of depository institutions (as such composite rate shall be determined by the NYFRB as set forth on the NYFRB’s Website from time to time) and published on the next succeeding Business Day by the NYFRB as an overnight bank funding rate.

“Payment”: as defined in Section 8.6(c).

“Payment Notice”: as defined in Section 8.6(c).

“Participant”: as defined in Section 9.6(b).

“Person”: an individual, partnership, limited liability company, corporation, business trust, joint stock company, trust, unincorporated association, joint venture, Governmental Authority or other entity of whatever nature.

“Plan”: at a particular time, any employee benefit plan covered by ERISA which any Registrant or any Fund maintains.

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“Prime Broker Agreement”: As to the Funds listed on Schedule V, the related agreement set forth on Schedule V.

“Proceeding” means any claim, litigation, investigation, action, suit, arbitration or administrative, judicial or regulatory action or proceeding in any jurisdiction.

“Pro Rata Allocation”: as to each Borrower, the percentage amount stated in Schedule Ia; provided that, if no Event of Default shall have occurred and be continuing, Columbia Management, on behalf of the Borrowers and without the consent of the Lenders, by written notice to the Administrative Agent, may change the Pro Rata Allocations from time to time in Columbia Management’ sole discretion; provided further, that while an Event of Default has occurred and is continuing with respect to a Borrower, the Pro Rata Allocations may be changed in such manner as long as the Pro Rata Allocation of any such defaulting Borrower is not increased; and provided further, that, after any change in Pro Rata Allocations, the aggregate amount of all Pro Rata Allocations shall equal 100%. The delivery of such written notice shall constitute a representation and warranty by the Borrowers as of the date thereof that no Event of Default has occurred and is continuing with respect to each Borrower whose Pro Rata Allocation has been increased.

“Prospectus”: at a particular time, and as to a Fund, the currently effective prospectus and statement of additional information of such Fund.

“Reference Time”: with respect to any setting of Daily Simple SOFR, the time determined by the Administrative Agent in its reasonable discretion and in consultation with the Borrowers.

“Register”: as defined in Section 9.6(d).

“Registrant”: as defined in the Preamble hereto.

“Registration Statement”: as to a Fund, the applicable portions of the registration statement of the Registrant of which such Fund is a series as filed with the Securities and Exchange Commission under the Securities Act and the 1940 Act.

“Regulation T”: Regulation T of the Board of Governors of the Federal Reserve System as in effect from time to time.

“Regulation U”: Regulation U of the Board of Governors of the Federal Reserve System as in effect from time to time.

“Regulation X”: Regulation X of the Board of Governors of the Federal Reserve System as in effect from time to time.

“Related Parties” means, with respect to any specified Person, such Person’s Affiliates and the respective directors, officers, employees, agents and advisors of such Person and such Person’s Affiliates.

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“Required Lenders”: at any time, Lenders having Credit Exposures and Available Commitments representing more than 50% of the sum of total Credit Exposures and Available Commitments at such time; provided that the Credit Exposure and Available Commitment of any Defaulting Lender shall be disregarded in the determination of the Required Lenders at any time and provided further that the Credit Exposures and Available Commitments of any Bank-Advisor shall be disregarded in the determination of the Required Lenders with respect to any amendment, modification, waiver or forbearance solely relating to the relevant Affected Borrower of such Bank-Advisor.

“Requirement of Law”: as to any Person, the certificate of incorporation, by-laws, partnership agreement, operating agreement or other organizational or governing documents of such Person, and any Applicable Law.

“Resolution Authority” means an EEA Resolution Authority or, with respect to any UK Financial Institution, a UK Resolution Authority.

“Responsible Officer”: the president, vice president, treasurer, secretary, assistant treasurer or assistant secretary of a Registrant, or, with respect to financial matters, the treasurer or assistant treasurer of such Registrant.

“Reverse Repurchase Transaction”: a transaction whereby a Borrower or Registrant, on behalf of a series thereof that is a Borrower, (i) transfers possession of a security it owns (but not record ownership or the right to receive interest and principal payments thereon) to another party in exchange for a percentage of the value of the security (for purposes of this definition, the “payment proceeds”), and (ii) repossesses the security at an agreed upon future date by remitting the payment proceeds plus interest.

“Revolving Credit Loan”: as defined in Section 2.1.

“Revolving Credit Note”: as defined in Section 2.5(e).

“S&P”: Standard & Poor’s Ratings Services, a division of The McGraw-Hill Companies.

“Sanctions” means economic or financial sanctions or trade embargoes imposed, administered or enforced from time to time by the U.S. government, the United Nations or the European Union and its member countries, including those administered by the Office of Foreign Assets Control of the U.S. Department of the Treasury or the U.S. Department of State, the United Nations Security Council, the European Union or Her Majesty’s Treasury.

“Sanctioned Country” means, at any time, a country or territory which is, or whose government is, the subject or target of any Sanctions.

“Sanctioned Person” means, at any time, (a) any Person that is the subject of any Sanctions, including without limitation any Person listed in any Sanctions-related list of designated Persons maintained by the Office of Foreign Assets Control of the U.S. Department of the Treasury or the U.S. Department of State, the United Nations Security Council, the European Union or Her Majesty’s Treasury, (b) any Person operating, located, organized or resident in a Sanctioned Country or (c) any Person owned or controlled by any such Person described in clauses (a) or (b).

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“Securities Act”: the Securities Act of 1933, as amended, together with all rules and regulations promulgated from time to time thereunder.

“Senior Securities Representing Indebtedness”: any Senior Security other than stock or other equity securities.

“Senior Security”: any bond, debenture, note or similar obligation or instrument constituting a security and evidencing indebtedness (including without limitation all Loans), and any share of beneficial interest or common stock, as the case may be, of a Fund, of a class (other than a class established in accordance with Section 18 of the 1940 Act) having priority over any other class of shares of such Fund as to distribution of assets or payment of dividends.

“SOFR”: for any day, a rate per annum equal to the secured overnight financing rate published by the SOFR Administrator on the SOFR Administrator’s Website on the immediately succeeding U.S. Government Securities Business Day.

“SOFR Administrator”: the NYFRB (or a successor administrator of the secured overnight financing rate).

“SOFR Administrator’s Website”: the NYFRB’s website, currently at http://www.newyorkfed.org, or any successor source for the secured overnight financing rate identified as such by the SOFR Administrator from time to time.

“Subsidiary”: as to any Person, a corporation, partnership, limited liability company or other entity of which shares of stock or other ownership interests having ordinary voting power (other than stock or such other ownership interests having such power only by reason of the happening of a contingency) to elect a majority of the board of directors or other managers of such corporation, partnership, limited liability company or other entity are at the time owned, or the management of which is otherwise controlled, directly or indirectly through one or more intermediaries, or both, by such Person. For the avoidance of doubt, any Fund or series of capital stock of a Registrant shall not constitute a Subsidiary.

“Swap Obligation”: as to any Person, any net obligation of such Person arising out of (i) any “swap agreement” (as defined in Section 101(53B) of the Bankruptcy Code), (ii) any equity swap, floor, collar, cap or option transaction, (iii) any option to enter into any of the foregoing or (iv) any combination of the foregoing.

“Swing Line Agent”: JPMorgan.

“Swing Line Commitment”: with respect to each Swing Line Lender, the obligation of such Swing Line Lender to make Swing Line Loans pursuant to Section 2.13 in an aggregate principal amount at any one time outstanding not to exceed the amount set forth opposite such Swing Line Lender’s name on Schedule II under the heading “Amount of Swing Line Commitment.”

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“Swing Line Exposure”: at any time, the aggregate principal amount of all Swing Line Loans outstanding at such time to all Borrowers. The Swing Line Exposure of any Lender at any time shall be the amount of such Lender’s funded or unfunded obligation to refund the aggregate Swing Line Loans outstanding at such time to all Borrowers (by funding Revolving Credit Loans under Section 2.15(a) or by purchasing a participating interest therein under Section 2.15(c)) based upon such Lender’s Commitment Percentage of the total Swing Line Exposure at such time, as such obligation may be adjusted pursuant to the terms of Section 2.2(b).

“Swing Line Lender”: each of JPMorgan, Citibank, N.A., and Wells Fargo Bank, National Association.

“Swing Line Loans”: as defined in Section 2.13.

“Swing Line Participation Amount”: as defined in Section 2.15(c).

“Swing Line Pro Rata Share”: (i) as to JPMorgan, 33.34%; (ii) as to Citibank, N.A., 33.33%; and (iii) as to Wells Fargo Bank, National Association, 33.33%.

“Termination Date”: October 27, 2022, or such earlier date on which the Commitments shall terminate as provided herein.

“Total Assets”: at any time, all assets of a Borrower which in accordance with GAAP would be classified as assets on a balance sheet of such Borrower prepared as of such time; provided, however, that the term Total Assets shall not include (a) equipment, (b) securities owned by a Borrower which are in default, (c) deferred organizational and offering expenses or (d) assets subject to any lien pursuant to a Prime Broker Agreement.

“Transactions” means the execution, delivery and performance by the Borrowers of this Agreement, the borrowing of Loans, the use of the proceeds thereof.

“Transferee”: as defined in Section 9.6(f).

“UCC”: the Uniform Commercial Code as from time to time in effect in the State of New York.

“UK Financial Institution”: any BRRD Undertaking (as such term is defined under the PRA Rulebook (as amended from time to time) promulgated by the United Kingdom Prudential Regulation Authority) or any person falling within IFPRU 11.6 of the FCA Handbook (as amended from time to time) promulgated by the United Kingdom Financial Conduct Authority, which includes certain credit institutions and investment firms, and certain affiliates of such credit institutions or investment firms.

“UK Resolution Authority”: the Bank of England or any other public administrative authority having responsibility for the resolution of any UK Financial Institution.

“Unaffected Borrower”: any Borrower other than an Affected Borrower.

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“U.S. Government Securities Business Day”: any day except for (i) a Saturday, (ii) a Sunday or (iii) a day on which the Securities Industry and Financial Markets Association recommends that the fixed income departments of its members be closed for the entire day for purposes of trading in United States government securities.

“Write-Down and Conversion Powers”: (a) with respect to any EEA Resolution Authority, the write-down and conversion powers of such EEA Resolution Authority from time to time under the Bail-In Legislation for the applicable EEA Member Country, which write-down and conversion powers are described in the EU Bail-In Legislation Schedule, and (b) with respect to the United Kingdom, any powers of the applicable Resolution Authority under the Bail-In Legislation to cancel, reduce, modify or change the form of a liability of any UK Financial Institution or any contract or instrument under which that liability arises, to convert all or part of that liability into shares, securities or obligations of that person or any other person, to provide that any such contract or instrument is to have effect as if a right had been exercised under it or to suspend any obligation in respect of that liability or any of the powers under that Bail-In Legislation that are related to or ancillary to any of those powers.

1.2 Other Definitional Provisions. (a) Unless otherwise specified therein, all terms defined in this Agreement shall have such defined meanings when used in any Note or other Loan Document or any certificate or other document made or delivered pursuant hereto.

(b) As used herein and in any Notes or other Loan Document, and any certificate or other document made or delivered pursuant hereto, accounting terms relating to any Registrant or Borrower not defined in Section 1.1 and accounting terms partly defined in Section 1.1, to the extent not defined, shall have the respective meanings given to them under GAAP (as consistently applied).

(c) The words “hereof”, “herein” and “hereunder” and words of similar import when used in this Agreement shall refer to this Agreement as a whole and not to any particular provision of this Agreement, and Section, subsection, Schedule and Exhibit references are to this Agreement unless otherwise specified.

(d) The meanings given to terms defined herein shall be equally applicable to both the singular and plural forms of such terms.

(e) For the avoidance of doubt, as used herein and in any Notes or other Loan Document, (a) the terms “Fund” and “Borrower” shall have the same meaning and (b) any reference to a Fund taking any action shall include the related Registrant, if any, taking such action on behalf of such Fund.

1.3 Assumptions Regarding Structure. For the sake of clarity and construction, the parties hereto hereby set forth their acknowledgment and agreement that each Borrower that is a series of a Registrant is not a separately existing legal entity entitled to enter into contractual agreements or to execute instruments and, for these reasons, each such Registrant is executing this Agreement and shall execute any respective Note on behalf of its series, as Borrowers, and that such series will utilize the Loans thus made on their behalf. Any action to be taken by a Borrower may be taken by the related Registrant on its behalf.

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Notwithstanding anything to the contrary in this Agreement, each Borrower shall be liable hereunder only for the Loans made to such Borrower hereunder and interest thereon and for the fees and expenses associated therewith and as otherwise set forth herein, and in no event shall any Borrower or its assets be held liable for the Loans made to any other Borrower hereunder or interest thereon or for the fees and expenses associated therewith.

1.4 Interest Rates. The interest rate on a Loan may be derived from an interest rate benchmark that may be discontinued or is, or may in the future become, the subject of regulatory reform. During the continuance of a Benchmark Unavailability Period, the interest rate for Loans will be determined in accordance with the definition of Federal Funds Rate. The Administrative Agent does not warrant or accept any responsibility for, and shall not have any liability with respect to, the administration, submission, performance or any other matter related to any interest rate used in this Agreement, or with respect to any alternative or successor rate thereto, or replacement rate thereof, including without limitation, whether the composition or characteristics of any such alternative, successor or replacement reference rate will be similar to, or produce the same value or economic equivalence of, the existing interest rate being replaced or have the same volume or liquidity as did any existing interest rate prior to its discontinuance or unavailability. The Administrative Agent and its affiliates and/or other related entities may, in the ordinary course of their business, engage in transactions that affect the calculation of any interest rate used in this Agreement or any alternative, successor or alternative rate and/or any relevant adjustments thereto, in each case, in a manner adverse to the Borrowers. The Administrative Agent may select information sources or services in its reasonable discretion to ascertain any interest rate used in this Agreement, any component thereof, or rates referenced in the definition thereof, in each case pursuant to the terms of this Agreement, and shall have no liability to the Borrowers, any Lender or any other person or entity for damages of any kind, including direct or indirect, special, punitive, incidental or consequential damages, costs, losses or expenses (whether in tort, contract or otherwise and whether at law or in equity), for any error or calculation of any such rate (or component thereof) provided by any such information source or service.

SECTION 2. AMOUNT AND TERMS OF COMMITMENTS

2.1 Commitments. Subject to the terms and conditions hereof, each Lender severally agrees to make revolving credit loans in Dollars (“Revolving Credit Loans”) to each Borrower, from time to time during the Commitment Period, in an aggregate principal amount at any one time outstanding not to exceed the amount of such Lender’s Commitment at such time minus the amount of such Lender’s Swing Line Exposure at such time. During the Commitment Period, each Borrower may use Commitments by borrowing, prepaying Loans in whole or in part, and reborrowing, all in accordance with the terms and conditions hereof; provided that (i) at no time may the aggregate principal amount outstanding of Revolving Credit Loans and Swing Line Loans to all Borrowers exceed the Aggregate Commitment and (ii) in no event shall any Lender be obligated to make Revolving Credit Loans or Swing Line Loans if it would cause the sum of the aggregate principal amount of such Lender’s Revolving Credit Loans, Swing Line Participation Amounts and Swing Line Loans to exceed such Lender’s Commitment.

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2.2 Procedure for Borrowing. (a) A Borrower may borrow under the Commitments during the Commitment Period on any Business Day, provided that the Borrower (or a Registrant on its behalf) shall give the Administrative Agent irrevocable notice (which notice must be received by the Administrative Agent prior to 1:00 P.M. New York City time on the requested Borrowing Date in accordance with Section 9.2), specifying (i) the amount to be borrowed, and (ii) the requested Borrowing Date. Subject to Section 2.15, the aggregate amount of each borrowing by a Borrower under the Commitments on any Borrowing Date shall be in an amount equal to $100,000 or a whole multiple of $100,000 in excess thereof (or, if the then Available Commitments are less than $100,000, such lesser amount). Upon receipt of any such notice from a Borrower (or a Registrant on its behalf), the Administrative Agent shall promptly notify each Lender thereof. Each Lender will make the amount of its pro rata share of each borrowing available to the Administrative Agent for the account of such Borrower at the office of the Administrative Agent specified in Section 9.2 prior to 4:00 P.M., New York City time, on the Borrowing Date requested by such Borrower in funds immediately available to the Administrative Agent. Such borrowing will then be made available to such Borrower on such Borrowing Date by the Administrative Agent’s transferring by wire to the account of such Borrower the aggregate of the amounts made available to the Administrative Agent by the Lenders and in like funds as received by the Administrative Agent; provided that if, on the Borrowing Date of any Revolving Credit Loans of a Borrower, any Swing Line Loans to such Borrower shall be outstanding, the proceeds of such Revolving Credit Loans to such Borrower shall first be applied to pay in full such Swing Line Loans, with any remaining proceeds to be made available to such Borrower as provided above.

(b) Notwithstanding any other provision hereof to the contrary, the Bank-Advisors may not, and shall not have the obligation to, (i) lend to (including, without limitation as a Swing Line Lender), (ii) participate or purchase a participation in, or make a Revolving Credit Loan to refund, repay or refinance, any Loan (including, without limitation, any Swing Line Loan) made by an Other Lender (including, without limitation, the Swing Line Lender) to, or (iii) share in a Benefited Lender’s excess payment or benefits of collateral or proceeds received from, in each case, any of their respective Affected Borrowers. With respect to a borrowing to be made by any Affected Borrower(s) (with borrowings made or to be made by and Loans made or to be made to any Affected Borrower or any Unaffected Borrower to include, for purposes of this Section 2.2(b), borrowings and Loans which are or are to be made to refund, refinance or repay Swing Line Loans made to such Affected Borrower or such Unaffected Borrower and participations which are or are to be purchased in Swing Line Loans and other Loans to such Affected Borrower or such Unaffected Borrower), the portion of such borrowing otherwise allocable to the related Bank-Advisor shall be allocated by the Administrative Agent to the Other Lenders (to the extent they have availability under their Commitments, and provided that no Lender shall be required to lend in excess of its Commitment) pro rata according to the amounts of their respective Available Commitments. Whenever borrowings are to be made by one or more Affected Borrowers and one or more Unaffected Borrowers on the same day, then for purposes of calculating the Lenders’ respective pro rata shares of borrowings by such Unaffected Borrower(s) there shall first be deducted from the Available Commitment of each Other Lender the amount of the Loans to be made by such Other Lender to the Affected Borrower(s) on such day. In the event that Loans are outstanding to one or more Affected Borrowers and as a result thereof, not all of the Aggregate Commitment is available to be borrowed by one or more Unaffected Borrowers, each Bank-Advisor that has previously not lent to such Affected Borrower(s) shall lend any or all such amounts not lent to such Affected Borrower(s) to such Unaffected Borrower(s) to the extent requested by it in conformance with the terms hereof but in no event more than its Available Commitment.

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2.3 Fees. (a) Each Borrower severally, and neither jointly nor jointly and severally, agrees to pay to the Administrative Agent for the account of each Lender such Borrower’s Pro Rata Allocation (as adjusted from time to time in accordance with the terms hereof) of a commitment fee (“Commitment Fee”) during the period which shall begin on the first day of the Commitment Period and shall extend to the Termination Date, which Commitment Fee shall be a quarterly fee, computed at the rate of 0.15% per annum on, subject to the last sentence of this Section 2.3, the average daily amount of the Available Commitments of all Lenders in the aggregate during each calendar quarter. Such Commitment Fees shall be payable quarterly in arrears for the period ending on each Commitment Fee Accrual Date, payable on the corresponding Commitment Fee Payment Date, commencing on the first Commitment Fee Payment Date to occur after the date hereof. Notwithstanding any other provision hereof to the contrary, solely for the purpose of calculating the Commitment Fee, Swing Line Loans will not be deemed a utilization of the Aggregate Commitments of all Lenders.

(b) Each Borrower severally agrees to pay the Administrative Agent for the account of the Administrative Agent the fees to which it has separately agreed.

2.4 Termination and Reduction of Commitments. (a) Each Borrower shall have the right, upon not less than three Business Days’ notice to the Administrative Agent, to terminate all Commitments and this Agreement, except with respect to provisions which by their terms are expressly stated to survive termination, with respect to such Borrower. Any termination of all Commitments to a Borrower shall be effective as of the last day of the calendar quarter in which such notice is given (or, if effected in connection with a merger permitted under Section 6.5, on the effective date of such merger), and shall be accompanied by prepayment in full of the Loans to such Borrower then outstanding, and payment of such Borrower’s Pro Rata Allocation of (i) any accrued Commitment Fees payable by such Borrower hereunder and (ii) any other accrued fees, expenses or indemnified liabilities payable by such Borrower hereunder. The amount of the Aggregate Commitment shall not be affected by any Borrower’s termination. Prior to such termination, Columbia Management shall notify the Administrative Agent in writing as to the Pro Rata Allocations of the remaining Borrowers, effective as of the termination, which notice shall constitute a representation and warranty by each of the remaining Borrowers that no Event of Default has occurred and is continuing with respect to each Borrower whose Pro Rata Allocation has been increased.

(b) Interest accrued on the amount of any prepayment relating to such termination and any unpaid Commitment Fee accrued hereunder shall be paid on the date of such termination.

(c) Upon the effective date of such termination, the terminating Borrower shall no longer be obligated to pay Commitment Fees hereunder or any share of any other fees, expenses, or indemnified liabilities that may accrue thereafter.

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(d) The Borrowers shall have the right, upon not less than three Business Days’ notice to the Administrative Agent, to reduce the Aggregate Commitment. Any such reduction shall be accompanied by prepayment in full of the Loans to the Borrowers then outstanding that are in excess of the Aggregate Commitment as reduced.

(e) The Administrative Agent shall provide each Lender with prompt notice of any Commitment changes pursuant to this Section 2.4.

2.5 Repayment of Loans; Evidence of Debt. (a) Each Borrower hereby severally and unconditionally, but not jointly or jointly and severally, promises to pay to the Administrative Agent for the account of each Lender the then unpaid principal amount of each Loan of such Lender to such Borrower on the Maturity Date for such Loan (or such earlier date on which the Loans become due and payable pursuant to Section 2.4(a), 2.4(d), 2.6(b) or 7). Each Borrower hereby further severally, but not jointly or jointly and severally, agrees to pay to the Administrative Agent for the account of each Lender interest on the unpaid principal amount of the Loans to such Borrower from time to time outstanding from the date hereof until payment in full thereof at the rates per annum, and on the dates, set forth in Section 2.7.

(b) Each Lender shall maintain in accordance with its usual practice an account or accounts evidencing indebtedness of each Borrower to such Lender resulting from each Loan of such Lender from time to time, including the amounts of principal and interest payable and paid to such Lender from time to time under this Agreement.

(c) The Administrative Agent shall maintain the Register pursuant to Section 9.6(d), and a subaccount therein for each Lender, in which shall be recorded (i) the amount of each Loan made hereunder, (ii) the amount of any principal or interest due and payable or to become due and payable from each Borrower to each Lender hereunder and (iii) the amount of any principal or interest and any other payments received by the Administrative Agent hereunder from each Borrower and each Lender’s share thereof. The Administrative Agent shall provide a copy of the Register to each Borrower promptly upon request.

(d) The entries made in the Register and the accounts of each Lender maintained pursuant to Section 2.5(b) shall, to the extent permitted by Applicable Law, be prima facie evidence of the existence and amounts of the obligations of the Borrowers therein recorded; provided, however, that the failure of any Lender or the Administrative Agent to maintain the Register or any such account, or any error therein, shall not in any manner affect the obligation of any Borrower to repay (with applicable interest) the Loans made to such Borrower by such Lender in accordance with the terms of this Agreement. In the event of a conflict between the Register and such accounts, the Register shall be rebuttably presumed to be correct.

(e) Each Registrant agrees that, upon the request of any Lender to the Administrative Agent, such Registrant will execute and deliver to such Lender a promissory note evidencing the Loans of such Lender to its applicable Borrower substantially in the form of Exhibit 2.5(e) with appropriate insertions as to date and principal amount (a “Revolving Credit Note”).

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(f) The obligations of each Borrower under its Notes and this Agreement shall be several and neither joint nor joint and several. Notwithstanding anything to the contrary contained in this Agreement, the parties hereto acknowledge and agree that the sole source of payment of the obligations of each Borrower hereunder, including, without limitation, the principal of and interest on each Loan made hereunder to any Borrower, the Commitment Fee payable pursuant to Section 2.3 and any other amounts attributable to the Loans made hereunder to any Borrower shall be the revenues and assets of such Borrower, and not the revenues and assets of any other Borrower (except as provided in Section 9.5(f)) or the revenues and assets of the respective Registrant acting on behalf of a Borrower (except to the extent of the revenues and assets of such Borrower).

2.6 Optional and Mandatory Prepayments. (a) Each Borrower may prepay the Loans made to it, in whole or in part, without premium or penalty, upon at least one Business Day’s notice to the Administrative Agent, specifying the date and amount of prepayment. Upon receipt of any such notice the Administrative Agent shall promptly notify each Lender thereof. If any such notice is given, the amount specified in such notice shall be due and payable on the date specified therein. Partial prepayments shall be in an aggregate principal amount of at least $100,000.

(b) If, at any time and from time to time, either (i) (x) for each Borrower other than Designated Borrowers, the Asset Coverage Ratio for such Borrower shall be less than 300%, or (y) for each Designated Borrower, the Asset Coverage Ratio shall be less than the Designated Borrower Asset Coverage Ratio Percentage for such Designated Borrower, or (ii) the aggregate amount of all borrowings of a Borrower (including without limitation the Loans made to a Borrower) then outstanding exceeds the borrowing limits provided in such Borrower’s Prospectus; then in each case within three Business Days thereafter such Borrower shall repay Loans made to such Borrower to the extent necessary to ensure that (x) the Asset Coverage Ratio of all borrowings of such Borrower after such payments is in compliance with applicable covenants concerning minimum Asset Coverage Ratios set forth in this Agreement and (y) the aggregate amount of all borrowings made to such Borrower then outstanding does not after such payments exceed such limits, as the case may be.

2.7 Interest Rates and Payment Dates. (a) Each Loan shall bear interest at a rate per annum equal to the Federal Funds Rate plus the Applicable Margin.

(b) Upon (i) the occurrence and continuance of any Event of Default specified in Section 7(e) with respect to a Borrower or (ii) notice given by the Administrative Agent or the Required Lenders to the Borrower of any other Event of Default, all Loans outstanding to such Borrower shall bear interest at a rate per annum which is the rate that would otherwise be applicable thereto pursuant to the provisions of Section 2.7(a), plus 2%. If all or a portion of (i) the principal amount of any Loan, (ii) any interest payable thereon or (iii) any Commitment Fee or other amount payable

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hereunder shall not be paid when due (whether at the stated maturity, by acceleration or otherwise), such overdue amount shall bear interest at a rate per annum equal to the Federal Funds Rate plus the Applicable Margin plus 2% from the date of such non-payment until such amount is paid in full. For the avoidance of doubt, the parties hereby agree that the maximum amount of interest payable on the principal amount of any Loan pursuant to this Section 2.7 shall not exceed the sum of the Federal Funds Rate plus the Applicable Margin plus 2%.

(c) Interest for the period through, but excluding, each Interest Accrual Date shall be payable in arrears on the relevant Interest Payment Date, provided that interest accruing pursuant to the second sentence of paragraph (b) of this Section 2.7 shall be payable from time to time on demand.

2.8 Computation of Interest and Fees. (a) Commitment Fees and interest shall be calculated on the basis of a 360-day year for the actual days elapsed. Any change in the interest rate on a Loan resulting from a change in the Federal Funds Rate shall become effective as of the opening of business on the day on which such change becomes effective. The Administrative Agent shall as soon as practicable notify the Borrowers and the Lenders in writing of the effective date and the amount of each such change in interest rate.

(b) Each determination of an interest rate by the Administrative Agent pursuant to any provision of this Agreement shall be conclusive and binding on each Borrower and the Lenders in the absence of manifest error.

2.9 Pro Rata Treatment and Payments. (a) Each borrowing by a Borrower from the Lenders hereunder (except as set forth in Section 2.2(b)) shall be made pro rata according to the respective Commitment Percentages of the Lenders that are obligated to lend to such Borrower and any reduction of the Commitments of the Lenders shall be made pro rata according to the respective Commitment Percentages of the Lenders. Each payment by a Borrower on account of any Commitment Fee hereunder shall be made pro rata according to the respective Available Commitments of the Lenders. Each payment (including each prepayment) by a Borrower on account of principal of and interest on the Loans shall be made pro rata according to the respective outstanding principal amounts of the Loans of such Borrower then held by the Lenders. All payments (including prepayments) to be made by a Borrower hereunder, whether on account of principal, interest, fees or otherwise, shall be made no later than 12:00 Noon New York City time, on the due date thereof to the Administrative Agent, for the account of the Lenders, at the Administrative Agent’s office specified in Section 9.2, in Dollars, in immediately available funds and without set-off, counterclaim or deduction of any kind (other than deductions expressly permitted by this Agreement). The Administrative Agent shall distribute such payments to the Lenders promptly upon receipt in like funds as received. If any payment hereunder becomes due and payable on a day other than a Business Day, such payment shall be extended to the next succeeding Business Day, and, with respect to payments of principal, interest thereon shall be payable at the then applicable rate during such extension.

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(b) Unless the Administrative Agent shall have been notified in writing by any Lender prior to a borrowing that such Lender will not make the amount that would constitute its Commitment Percentage of such borrowing available to the Administrative Agent, the Administrative Agent may assume that such Lender is making such amount available to the Administrative Agent, and the Administrative Agent may, in reliance upon such assumption, make available to a Borrower a corresponding amount. If such amount is not made available by a Lender to the Administrative Agent by the required time on the Borrowing Date therefor, such Lender shall pay to the Administrative Agent, on demand, such amount with interest thereon at a rate equal to the daily average Federal Funds Rate for the period commencing with such Borrowing Date until such Lender makes such amount immediately available to the Administrative Agent (it being understood that none of the Borrowers shall be obligated to repay any such interest paid by the non-funding Lender). A certificate of the Administrative Agent submitted to any Lender with respect to any amounts owing under this Section shall be conclusive in the absence of manifest error. If such Lender’s Commitment Percentage of such borrowing is not made available to the Administrative Agent by such Lender within three Business Days of such Borrowing Date, the Administrative Agent shall also be entitled to recover such amount with interest thereon from the date of borrowing at the rate per annum applicable to Loans hereunder, on or before three Business Days following demand therefor, from the relevant Borrower (and such Borrower may borrow under the Commitments or under the Swing Line Commitment to satisfy such demand; provided that, for purposes of determining the Available Commitment, the Commitment of any non-funding Lender shall be excluded). The Administrative Agent shall request of each Lender other than the non-funding Lender that it fund the non-funding Lender’s defaulted Commitment (each such other Lender having no commitment or obligation so to fund in excess of its Commitment), and if such funding does not occur the Administrative Agent shall use its reasonable efforts to obtain funding of such defaulted Commitment from third-party lenders.

2.10 Requirements of Law. (a) If any Lender shall have reasonably determined that any Change in Law regarding capital or liquidity requirements or capital adequacy shall have the effect of reducing the rate of return on such Lender’s or such corporation’s capital as a consequence of its obligations hereunder to a level below that which such Lender or such corporation could have achieved but for such Change in Law (taking into consideration such Lender’s or such corporation’s reasonable policies with respect to capital adequacy) by an amount determined by such Lender to be material, then from time to time, each Borrower shall promptly pay to such Lender such additional amount or amounts as will reasonably compensate such Lender for such reduction. “Change in Law” means (a) the adoption of any law, rule or regulation after the date of this Agreement by any Governmental Authority, (b) any change in any law, rule or regulation or in the interpretation or application thereof by any Governmental Authority after the date of this Agreement or (c) compliance by any Lender (or, for purposes of this Section 2.10(a), by any lending office of such Lender or by such Lender’s holding company, if any) with any request, guideline or directive (whether or not having the force of law) of any Governmental Authority made or issued after the date of this Agreement. Notwithstanding anything herein to the contrary, (i) the Dodd-Frank Wall Street Reform and Consumer Protection Act and all requests, rules, guidelines or directives promulgated by any relevant Government Authority thereunder or issued in connection therewith shall be deemed to be a “Change in Law”, regardless of the date enacted, adopted or issued, and (ii) all requests, rules, guidelines, requirements and directives promulgated by the Bank for International Settlements, the Basel Committee on Banking Supervision (or any successor or similar authority) or any relevant Government Authority, in each case pursuant to Basel III, shall in each case be deemed to be a “Change in Law” regardless of the date enacted, adopted, issued or implemented.

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(b) If any Lender becomes entitled to claim, and determines that it will collect from the Borrowers, any additional amounts pursuant to this Section, it shall promptly notify the Borrowers (with a copy to the Administrative Agent) of the event by reason of which it has become so entitled by providing a certificate setting forth in reasonable detail the basis for the claim for additional amounts, the amounts required to be paid by the Borrowers to such Lender, and the computations made by such Lender to determine the amounts; provided that such Lender shall not be required to disclose any confidential information. Such certificate as to any additional amounts payable pursuant to this Section submitted by such Lender to the Borrowers (with a copy to the Administrative Agent) shall be conclusive in the absence of manifest error. The agreements in this Section shall survive the termination of this Agreement and the payment of the Loans and all other amounts payable hereunder. No Borrower shall be responsible to compensate such Lender for additional amounts attributable to another Borrower’s Loans.

(c) Failure or delay on the part of any Lender to demand compensation pursuant to this Section shall not constitute a waiver of such Lender’s right to demand such compensation; provided that the Borrowers shall not be required to compensate a Lender pursuant to this Section for any increased costs or reductions incurred more than 45 days prior to the date that such Lender notifies the Borrowers of the change in the Requirement of Law giving rise to such increased costs or reductions and of such Lender’s intention to claim compensation therefor; provided further that, if the change in the Requirement of Law giving rise to such increased costs or reductions is retroactive, then the 45-day period referred to above shall be extended to include the period of retroactive effect thereof.

(d) Each Lender agrees that, upon the occurrence of any event giving rise to the operation of Section 2.10(a) with respect to such Lender, it will, if requested by the Borrowers, use reasonable efforts (subject to overall policy considerations of such Lender) to avoid or mitigate any additional amounts payable to the greatest extent practicable (including transferring the Loans affected by such event to another lending office), unless in the opinion of such Lender, such efforts would result in such Lender (or its lending office) suffering an economic, legal or regulatory disadvantage. Nothing in this clause (d) shall affect or postpone any of the obligations of the Borrowers or the right of any Lender provided in this Section 2.10.

(e) The agreements in this Section shall survive termination of the Commitments, this Agreement and repayment of the Loans and all amounts payable hereunder.

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2.11 Taxes. (a) All payments made by any Borrower under this Agreement and any Notes shall be made free and clear of, and without deduction or withholding for or on account of, any present or future income, stamp or other taxes, levies, imposts, duties, charges, fees, deductions or withholdings, now or hereafter imposed, levied, collected, withheld or assessed by any Governmental Authority, excluding (i) all present and future income taxes and franchise taxes (imposed in lieu of net income taxes) imposed on the Administrative Agent or any Lender as a result of a present or former connection between the Administrative Agent or such Lender and the jurisdiction of the Governmental Authority imposing such tax or any political subdivision or taxing authority thereof or therein (other than any such connection arising solely from the Administrative Agent or such Lender having executed, delivered or performed its obligations or received a payment under, or enforced, this Agreement or any Note), (ii) any tax imposed by reason of any present or former connection between the jurisdiction imposing such tax and a Lender other than a connection arising from such Lender having executed, delivered or performed its obligations under, or received payment under, or enforced this Agreement, (iii) any tax that is imposed otherwise than by withholding by the Borrowers from such payments (other than a tax imposed on a Lender due to the Borrower’s failure to deduct or withhold such tax), and any interest, penalties (unless due to a Lender’s actions or failure to take actions that (x) were not caused by a Borrower and (y) are legally required to avoid such penalty) or similar liabilities with respect thereto, or (iv) any U.S. federal withholding taxes imposed under FATCA. If any such non-excluded taxes, levies, imposts, duties, charges, fees deductions or withholdings (“Non-Excluded Taxes”) are required to be withheld from any amounts payable to the Administrative Agent or any Lender hereunder or under any Note, the amounts so payable to the Administrative Agent or such Lender shall be increased to the extent necessary to yield to the Administrative Agent or such Lender (after payment of all Non-Excluded Taxes) interest or any such other amounts payable hereunder at the rates or in the amounts specified in this Agreement, provided, however, that a Borrower shall not be required to increase any such amounts payable to any Lender that is organized under the laws of a jurisdiction outside the United States of America if such Lender fails to comply with the requirements of paragraph (c) of this Section. Whenever any Non-Excluded Taxes are payable by a Borrower, as promptly as possible thereafter such Borrower shall send to the Administrative Agent for its own account or for the account of such Lender, as the case may be, a certified copy of an original official receipt received by such Borrower showing payment thereof. If a Borrower fails to pay any Non-Excluded Taxes when due to the appropriate taxing authority or fails to remit to the Administrative Agent the required receipts or other required documentary evidence, such Borrower shall indemnify the Administrative Agent and the Lenders for any incremental taxes, interest or penalties that may become payable by the Administrative Agent or any Lender as a result of any such failure. The agreements in this Section shall survive the termination of this Agreement and the payment of the Loans and all other amounts payable hereunder.

(b) If a Borrower pays any additional amount pursuant to this Section 2.11 to a Lender and such Lender determines in good faith, that it has actually received or realized in connection therewith any refund or any reduction of, or credit against, its Non-Excluded Tax liabilities in or with respect to the taxable year in which the additional amount is paid (a “Tax Benefit”), such Lender shall pay to such Borrower an amount that such Lender shall, in good faith, determine is equal to the net benefit, after tax, which was obtained by such Lender in such year as a consequence of such Tax Benefit, provided, however, that (i) any Lender may determine, in good faith, consistent with the policies of such Lender, whether to seek a Tax Benefit (provided that a Lender shall claim a Tax Benefit if it determines in good faith that claiming such Tax Benefit will not otherwise be disadvantageous to such Lender); (ii) any Non-Excluded Taxes that are

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imposed on a Lender as a result of a disallowance or reduction (including through the expiration of any tax credit carryover or carryback of such Lender that otherwise would not have expired) of any Tax Benefit with respect to which such Lender has made a payment to a Borrower pursuant to this Section 2.11(b) shall be treated as a Non-Excluded Tax for which such Borrower is obligated to indemnify such Lender pursuant to this Section 2.11; (iii) nothing in this Section 2.11(b) shall require any Lender to disclose any confidential information to any Borrower (including, without limitation, its tax returns); and (iv) no Lender shall be required to pay any amounts pursuant to this Section 2.11(b) at any time during which a Default or Event of Default has occurred and is continuing. Any payment (or determination that no payment is due) by a Lender with respect to a Tax Benefit pursuant to this Section 2.11 shall be accompanied by a schedule reasonably detailing the calculations for determining the amount of the Tax Benefit, provided, however, that no Lender shall be required to substantiate the basis of its calculations.

(c) Each Lender shall:

(i) deliver to Columbia Management and the Administrative Agent prior to any payments being made under this Agreement or the Notes (A) if such Lender is organized under the laws of a jurisdiction outside the United States of America, two duly completed copies of United States Internal Revenue Service Form W-8BEN-E, Form W-8IMY or Form W-8ECI, or successor applicable forms, appropriate for such Lender, or (B) if such Lender is organized under the laws of a jurisdiction within the United States of America, an Internal Revenue Service Form W-9, or successor form;

(ii) deliver to Columbia Management and the Administrative Agent two further properly completed copies of any such form or certification on or before the date that any such form or certification expires or becomes obsolete and after the occurrence of any event requiring a change in the most recent form previously delivered by it to Columbia Management; and

(iii) obtain such extensions of time for filing and complete such forms or certifications as may reasonably be requested by Columbia Management or the Administrative Agent;

unless in any such case an event (including, without limitation, any change in treaty, law or regulation) has occurred prior to the date on which any such delivery would otherwise be required which renders all such forms inapplicable or which would prevent such Lender from lawfully completing and delivering any such form with respect to it and such Lender so advises Columbia Management and the Administrative Agent. Such Lender shall certify (A) in the case of a Form W-8BEN-E, Form W-8IMY or Form W-8ECI, that it is entitled to receive payments under this Agreement without deduction or withholding of any United States federal income taxes and (B) in the case of a Form W-9, that it is entitled to an exemption from United States backup withholding tax. Each Person that shall become a Lender or a Participant

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pursuant to Section 9.6 shall, upon the effectiveness of the related transfer, be required to provide all of the forms and statements required pursuant to this Section, provided that in the case of a Participant such Participant shall furnish all such required forms and statements to the Lender from which the related participation shall have been purchased. If a payment made to any Lender or the Administrative Agent under this Agreement or any Notes would be subject to U.S. federal withholding tax imposed by FATCA if such Lender or the Administrative Agent were to fail to comply with the applicable reporting requirements of FATCA (including those contained in Section 1471(b) or 1472(b) of the Code, as applicable), such Lender or the Administrative Agent shall deliver to the Borrowers and the Administrative Agent at the time or times prescribed by Applicable Law and at such time or times reasonably requested by the Borrowers or the Administrative Agent such documentation prescribed by Applicable Law (including as prescribed by Section 1471(b)(3)(C)(i) of the Code) and such additional documentation reasonably requested by the Borrowers or the Administrative Agent as may be necessary for the Borrowers and the Administrative Agent to comply with their obligations under FATCA, to determine whether such Lender or the Administrative Agent has or has not complied with such Lender’s or the Administrative Agent’s obligations under FATCA or to determine the amount, if any, to deduct and withhold from such payment. Solely for purposes of this Section 2.11(c), “FATCA” shall include any amendments made to FATCA after the date of this Agreement.

(d) For purposes of determining withholding taxes imposed under FATCA, from and after the Closing Date, the Borrower and the Administrative Agent shall treat (and the Lenders hereby authorize the Administrative Agent to treat) the Agreement as not qualifying as a “grandfathered obligation” within the meaning of Treasury Regulation Section 1.1471-2(b)(2)(i).

(e) The agreements in this Section shall survive termination of the Commitments, this Agreement and repayment of the Loans and all amounts payable hereunder.

2.12 Change of Lending Office; Replacement of Lender. (a) Each Lender agrees that if it makes any demand for payment under Section 2.10, or any additional amounts are payable under Section 2.11, it will use reasonable efforts (consistent with its internal policy and legal and regulatory restrictions and so long as such efforts would not be disadvantageous to it, as determined in its sole discretion) to designate a different lending office if the making of such a designation would reduce or obviate the need for a Borrower to make payments under Section 2.10 or payment of additional amounts under Section 2.11.

(b) If any Lender (the “Replaced Lender”) (i) shall have required compensation pursuant to Section 2.10, or payment of additional amounts under Section 2.11, or (ii) is a Defaulting Lender, the Borrowers shall have the right, with the consent of the Administrative Agent (which shall not be unreasonably withheld), to substitute such Replaced Lender with an Eligible Lender whose compensation requirements, if any, in respect of such sections are less than those of the Replaced Lender (such Eligible Lender, a “Replacement Lender”) satisfactory to the Borrowers (which may be one or more of the other then existing Lenders if they, in their sole discretion, elect to become such Replacement Lender) to assume the Commitment of such Replaced Lender and to purchase the Notes held by such Replaced Lender, if any, for an amount equal to the

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principal of, and accrued and unpaid interest on, such Notes, together with the fee specified in Section 9.6(e) and any other costs reasonably incurred by such Replaced Lender in connection with its sale of such Notes and the assignment of such Commitment (without recourse to or warranty by such Replaced Lender and subject to all amounts due and owing to such Lender under this Agreement having been paid in full). Upon the exercise of such right by the Borrowers and the satisfaction of such conditions thereto, such Replaced Lender shall convey its interest to the Replacement Lender in accordance with the procedures set forth in Section 9.6(c).

2.13 Swing Line Commitment. Subject to the terms and conditions hereof, each Swing Line Lender agrees to make available to each Borrower a portion of the credit otherwise available under the Commitments from time to time during the Commitment Period by making swing line loans (“Swing Line Loans”) to such Borrower in an aggregate principal amount not to exceed at any one time outstanding such Swing Line Lender’s Swing Line Commitment; provided, however, that the Swing Line Loans outstanding at any time, when aggregated with such Swing Line Lender’s other outstanding Revolving Credit Loans hereunder, may not exceed the Swing Line Lender’s Commitment then in effect; and provided further, however, that on the date of the making of any Swing Line Loan and while any Swing Line Loan is outstanding, the sum of the aggregate principal amount of all outstanding Revolving Credit Loans and Swing Line Loans shall not exceed the Aggregate Commitment (less the Commitment of any non-funding Lender referred to in Section 2.9(b)). During the Commitment Period applicable to each Borrower, such Borrower may use the Swing Line Commitment by borrowing, repaying and reborrowing, all in accordance with the terms and conditions hereof. Each Swing Line Loan shall bear interest at a rate per annum equal to the Federal Funds Rate plus the Applicable Margin. In no event shall any Lender be obligated to make Revolving Credit Loans or Swing Line Loans if it would cause the sum of the aggregate principal amount of such Lender’s Revolving Credit Loans, Swing Line Participation Amounts and Swing Line Loans to exceed such Lender’s Commitment.

2.14 Procedure for Swing Line Borrowing. Whenever a Borrower desires that the Swing Line Lenders make Swing Line Loans under Section 2.13, the Borrower (or the applicable Registrant of which it is a series) shall give the Swing Line Agent irrevocable telephonic notice confirmed promptly in writing, by facsimile or other mutually acceptable electronic transmission medium, to the attention of:

JPMORGAN CHASE BANK, N.A.

500 Stanton Christiana Road, NCC5

Newark, DE 19713

Attention: Andrew Weyant

Phone: (302) 552-0714

Fax: (302) 634 8459 / 12012443577@tls.ldsprod.com

Email: andrew.weyant@chase.com

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or such other person or persons which may be designated by the Swing Line Agent from time to time (which telephonic notice must be received by the Swing Line Agent not later than 4:00 P.M., New York City time, on the proposed Borrowing Date, and which written confirmation must be received by the Swing Line Agent on the proposed Borrowing Date in form and substance satisfactory to the Swing Line Agent), specifying the amount of each requested Swing Line Loan. Each borrowing under the Swing Line Commitment shall be in an amount equal to $250,000 or an integral multiple of $100,000 in excess thereof. Upon receipt of any such notice from a Borrower (or the applicable Registrant), the Swing Line Agent shall promptly notify the Administrative Agent thereof, and the Administrative Agent shall promptly notify the Swing Line Lenders thereof. Upon receipt of notice of a request for a Swing Line Loan from the Administrative Agent, each Swing Line Lender shall make its Swing Line Pro Rata Share of such borrowing available to such Borrower, on the Borrowing Date requested by such Borrower, by transferring such amount by wire or book entry to the account of such Borrower such Swing Line Loan in immediately available funds.

2.15 Refunding of Swing Line Loans. (a) Either the Swing Line Agent or the Administrative Agent, at any time in its sole and absolute discretion may, and on the seventh day (or if such day is not a Business Day, the next Business Day following the seventh day) after the Borrowing Date with respect to any Swing Line Loans to a Borrower shall, on behalf of such Borrower (and each Borrower hereby irrevocably directs the Swing Line Agent and Administrative Agent to so act on its behalf and with respect to such Borrower), upon notice given by the Swing Line Agent to the Administrative Agent, or by the Administrative Agent, no later than 10:00 A.M., New York City time, on the relevant refunding date, request each Lender to make, and, subject to Section 2.2(b), each Lender hereby agrees to make, a Revolving Credit Loan to such Borrower, at the rate applicable to the Swing Line Loans of such Borrower, in an amount equal to such Lender’s Commitment Percentage of the amount of such Swing Line Loans of such Borrower (the “Refunded Swing Line Loans”) outstanding on the date of such notice, to repay the Swing Line Lenders. Each Lender shall make the amount of such Revolving Credit Loan available to the Administrative Agent at its office set forth in Section 9.2 in immediately available funds, no later than 1:00 P.M., New York City time, on the date of such notice. The proceeds of such Revolving Credit Loans shall be distributed by the Administrative Agent to the Swing Line Lenders and immediately applied by the Swing Line Lenders to repay the Refunded Swing Line Loans. Effective on the day such Revolving Credit Loans are made, the portion of the Swing Line Loans so paid shall no longer be outstanding as Swing Line Loans. Notwithstanding any provision hereof to the contrary, if prior to the seventh day (or if such day is not a Business Day, the next Business Day following such seventh day) after the Borrowing Date with respect to any Swing Line Loan, any Swing Line Lender lending such Swing Line Loan requests the refunding of such Swing Line Loan as described in the first sentence above, the Administrative Agent shall effect the refunding of all outstanding Swing Line Loan as described above.

(b) The making of any Swing Line Loan hereunder at the request of a Borrower shall be subject to the satisfaction of the applicable conditions precedent thereto set forth in Section 4 (unless otherwise waived in accordance with Section 9.1).

(c) If prior to the making of a Revolving Credit Loan to a Borrower pursuant to Section 2.15(a) one of the events described in paragraph (e) of Section 7 shall have occurred with respect to such Borrower, each Lender severally, unconditionally and irrevocably agrees that it shall purchase a participating interest in the applicable Swing Line Loans (“Unrefunded Swing Line Loans”) in an amount equal to the amount (if any) of Revolving Credit Loans which would otherwise have been made by such Lender

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pursuant to Section 2.15(a). Each Lender will immediately transfer to the Administrative Agent, in immediately available funds, the amount of its participation (the “Swing Line Participation Amount”), and the proceeds of such participation shall be distributed by the Administrative Agent to the Swing Line Lenders in such amount as will reduce the amount of the participating interest retained by the Swing Line Lenders in their Swing Line Loans to the amount of the Revolving Credit Loans which were to have been made by it pursuant to Section 2.15(a).

(d) Whenever, at any time after any Swing Line Lender has received from any Lender such Lender’s Swing Line Participation Amount, such Swing Line Lender receives any payment on account of the Swing Line Loans, such Swing Line Lender will distribute to such Lender its Swing Line Participation Amount (appropriately adjusted, in the case of interest payments, to reflect the period of time during which such Lender’s participating interest was outstanding and funded and, in the case of principal and interest payments, to reflect such Lender’s pro rata portion of such payment if such payment is not sufficient to pay the principal of and interest on all Swing Line Loans then due); provided, however, that in the event that such payment received by such Swing Line Lender is required to be returned, such Lender will return to such Swing Line Lender any portion thereof previously distributed to it by such Swing Line Lender.

(e) Each Lender’s obligation to make the Revolving Credit Loans referred to in Section 2.15(a) and to purchase participating interests pursuant to Section 2.15(c) shall be absolute and unconditional and shall not be affected by any circumstance, including, without limitation, (i) any setoff, counterclaim, recoupment, defense or other right which such Lender may have against any Swing Line Lender or any other Person for any reason whatsoever; (ii) the occurrence or continuance of a Default or an Event of Default or the failure to satisfy any of the other conditions specified in Section 4; (iii) any adverse change in the condition (financial or otherwise) of any Borrower; (iv) any breach of this Agreement or any other Loan Document by any Borrower or any Lender; or (v) any other circumstance, happening or event whatsoever, whether or not similar to any of the foregoing, other than solely the gross negligence or willful misconduct of the Swing Line Lender in making a Swing Line Loan with actual knowledge by the officer responsible for the making of such Swing Line Loan that such Swing Line Loan is made without satisfaction of the applicable conditions precedent thereto set forth in Section 4 and without a waiver in accordance with Section 9.1.

(f) Each Borrower agrees to pay upon demand by any Swing Line Lender any Swing Line Loan made to such Borrower, or portion thereof, which is not refunded by the Lenders pursuant to this Section 2.15 (and such Borrower may borrow a Revolving Credit Loan under the Commitments to satisfy such demand; provided that, for purposes of determining the Available Commitment, the Commitment of any non-refunding Lender shall be excluded). Notwithstanding anything to the contrary contained in this Agreement, any Lender that fails to make available a Revolving Credit Loan pursuant to Section 2.15(a) or purchase a participating interest in a Swing Line Loan pursuant to Section 2.15(c) shall be deemed delinquent (a “Delinquent Lender”) and to the extent a Borrower subsequently repays any outstanding Revolving Credit Loans, the Delinquent Lender’s pro rata share of such repayment, if any, shall be paid by the Administrative Agent to the Swing Line Lenders, until the Delinquent Lender’s pro rata share of such Swing Line Loan is repaid in full.

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2.16 Designation of Additional Borrowers; Amendments to Schedule I. (a) Other series of the Registrants and other series of other investment companies registered under the 1940 Act, in either case for which Columbia Management or a Subsidiary of Columbia Management acts as the investment manager, may, with the prior written consent of the Administrative Agent, each Lender and each Fund, become parties to this Agreement in addition to those Borrowers listed on Schedule I, and be deemed Borrowers for all purposes of this Agreement by executing an instrument substantially in the form of Exhibit 2.16(a) (with such changes therein as may be approved by the Administrative Agent and the Lenders), which instrument shall (x) have attached to it a copy of this Agreement (as the same may have been amended) with a revised Schedule I and, if applicable, Schedule Ia, reflecting the participation of such additional portfolio or investment company, including (if the Administrative Agent deems it appropriate that the additional Borrower be a Designated Borrower) the appropriate Designated Borrower Asset Coverage Ratio Percentage as determined by the Administrative Agent, and any prior revisions to Schedule I and Schedule Ia effected in accordance with the terms hereof and (y) be accompanied by the documents and instruments required to be delivered by the Borrowers pursuant to Section 4.1, including, without limitation, an opinion of general counsel for the Borrowers in a form acceptable to the Administrative Agent.

(b) No Person shall be admitted as a party to this Agreement as a Borrower unless at the time of such admission and after giving effect thereto: (i) the representations and warranties set forth in Section 3 shall be true and correct with respect to such Borrower; (ii) such Borrower shall be in compliance in all material respects with all of the terms and provisions set forth herein on its part to be observed or performed at the time of the admission and after giving effect thereto; and (iii) no Default or Event of Default with respect to such Borrower shall have occurred and be continuing. The addition of any Borrower to this Agreement shall be further conditioned upon the delivery, to the extent requested by the Administrative Agent or any Lender, to the Administrative Agent or such Lender, as applicable, a Form FR U-1 executed by the applicable Registrant on behalf of such Borrower, together with a current list of assets of such Borrower (including all “margin stock” (as defined in Regulation U) of such Borrower) in conformity with the requirements of Form FR U-1.

2.17 Interfund Lending. (a) Notwithstanding anything in this Agreement to the contrary (including, without limitation, Sections 6.2, 6.3 and 6.8), Interfund Lending shall be expressly permitted hereunder, and the mere making or receipt of an Interfund Loan in and of itself shall not, with respect to any Borrower a party thereto (as a lender or a borrower), constitute a violation of any condition precedent, representation or covenant contained herein or constitute a Default or Event of Default; provided that all other terms and conditions of this Agreement are satisfied, and provided further, that:

(i) such Interfund Lending (1) is not otherwise prohibited by law, (2) has been duly authorized by each party thereto, (3) is consistent with the terms of the applicable Interfund Lending Exemptive Order, (4) is not in contravention of each applicable Borrower’s Prospectus, and (5) is deemed to be a Senior Security for purposes of calculating the Asset Coverage Ratio as it applies to each applicable Borrower;

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(ii) a Borrower may not be a lender of an Interfund Loan at any time during which such Borrower has any Loan outstanding;

(iii) if, at any time, an Interfund Loan is outstanding to a Borrower that has any Loans outstanding as well, and if at such time the Asset Coverage Ratio for such Borrower shall be less than the required Asset Coverage Ratio for such Borrower pursuant to this Agreement, then such Borrower shall repay such outstanding Interfund Loans and Loans on a pro rata basis and on the same repayment schedule (subject, in any and all events, to such Borrower’s obligation to prepay in accordance with Section 2.6(b)) to the extent necessary to ensure that the Asset Coverage Ratio of all borrowings of such Borrower after such payments is in compliance with applicable covenants concerning minimum Asset Coverage Ratios set forth in this Agreement;

(iv) if any payment with respect to an Interfund Loan would cause the Asset Coverage Ratio for a Borrower to be less than the required Asset Coverage Ratio for such Borrower pursuant to this Agreement, then such Borrower shall make any payments with respect to such outstanding Interfund Loans on a pro rata basis with payments with respect to Loans to the extent necessary to ensure that the Asset Coverage Ratio of all borrowings of such Borrower after such payments is in compliance with applicable covenants concerning minimum Asset Coverage Ratios set forth in this Agreement;

(v) a default by a Borrower with respect to an Interfund Loan shall constitute an Event of Default with respect to such Borrower for purposes of this Agreement;

(vi) if a Default or Event of Default with respect to a Borrower has occurred and is continuing under this Agreement other than as specified above in Section 2.17(a)(iii), then any payments made with respect to outstanding Interfund Loans shall be made on a pro rata basis with payments with respect to Loans until such Default or Event of Default is cured or waived;

(vii) if at any time a Borrower should secure an Interfund Loan or Interfund Loans with collateral, then such Borrower shall collateralize each Loan to such Borrower under this Agreement (I) in substantially the same manner and to substantially the same extent as is required with respect to each Interfund Loan to such Borrower, as more particularly described in the applicable Interfund Lending Exemptive Order and (II) with collateral having substantially the same liquidity and substantially similar credit characteristics as that of the collateral securing such Interfund Loan or Interfund Loans, provided that the collateral coverage percentage ratio for Loans shall not be less than the greater of (x) 102% or (y) the collateral coverage ratio for Interfund Loans; and

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(viii) for purposes of calculating the Asset Coverage Ratio of a Borrower, the amount equal to the aggregate value of the collateral securing an Interfund Loan or Loan minus the amount of such Interfund Loan or Loan, respectively, shall be subtracted from the value of Total Assets in the numerator of such Asset Coverage Ratio.

(b) Without otherwise limiting the purposes for which proceeds of a Loan may be used as specified in Section 5.8, a Borrower shall be expressly permitted to use the proceeds of a Loan to repay an outstanding Interfund Loan of such Borrower, subject to the conditions set forth in paragraph (a) of this Section 2.17 and the other conditions of this Agreement (including without limitation Section 5.8).

2.18 Defaulting Lender. Notwithstanding any provision of this Agreement to the contrary, if any Lender becomes a Defaulting Lender, then the following provisions shall apply for so long as such Lender is a Defaulting Lender:

(i) The Commitment Fee shall cease to accrue on the unfunded portion of the Commitment of such Defaulting Lender;

(ii) The Credit Exposure and Available Commitment of such Defaulting Lender shall not be included in determining whether the Required Lenders have taken or may take any action hereunder (including any consent to any amendment, waiver or other modification pursuant to Section 9.1); provided, that (i) such Defaulting Lender’s Commitment may not be increased or extended without its consent and (ii) the principal amount of, or interest payable on, Loans of such Defaulting Lender may not be reduced or excused or the scheduled date of payment may not be postponed as to such Defaulting Lender without such Defaulting Lender’s consent;

(iii) If any Swing Line Exposure exists at the time such Lender becomes a Defaulting Lender, then:

(a) all or any part of the Swing Line Exposure of such Defaulting Lender shall be reallocated among the non-Defaulting Lenders in accordance with their respective Commitment Percentages, provided that such reallocation does not cause the aggregate Credit Exposure of any non-Defaulting Lender to exceed its Commitment; and

(b) if the reallocation described in clause (i) above cannot, or can only partially, be effected, the applicable Borrowers shall, within two Business Days following notice by the Administrative Agent, prepay such Swing Line Exposure;

(iv) so long as such Lender is a Defaulting Lender, the Swing Line Lender shall not be required to fund any Swing Line Loan unless it is satisfied that the related exposure will be 100% covered by the Commitments of the non-Defaulting Lenders, and participating interests in any newly made Swing Line Loan shall be allocated among non-Defaulting Lenders in a manner consistent with Section 2.18(iii)(a) (and such Defaulting Lender shall not participate therein).

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(v) If a Swing Line Lender has a good faith belief that any Lender has defaulted in fulfilling its obligations under one or more other agreements in which such Lender commits to extend credit, such Swing Line Lender shall not be required to fund any Swing Line Loan unless such Swing Line Lender shall have entered into arrangements with the Borrower or such Lender, satisfactory to such Swing Line Lender to defease any risk to it in respect of such Lender hereunder.

(vi) In the event that the Administrative Agent, the Borrowers and the Swing Line Lender all agree that a Defaulting Lender has adequately remedied all matters that caused such Lender to be a Defaulting Lender, then the Swing Line Exposure of the Lenders shall be readjusted to reflect the inclusion of such Lender’s Commitment and on such date such Lender shall purchase at par such of the Loans of the other Lenders as the Administrative Agent shall determine may be necessary in order for such Lender to hold such Loans in accordance with its Commitment Percentage.

2.19 Limitation on Lender’s Obligations. Notwithstanding anything to the contrary contained in this Agreement or any other Loan Document or in any Exhibit or Schedule hereto or thereto, no Lender shall be obligated to make any Loan or purchase a participating interest in any Swing Line Loan if, immediately after giving effect thereto, the sum of (a) the outstanding principal balance of the Loans made by such Lender plus (b) the aggregate purchase prices of all such participating interests purchased by such Lender (less all payments received and retained by such Lender in reduction of such participating interests), would exceed such Lender’s Commitment.

SECTION 3. REPRESENTATIONS AND WARRANTIES

To induce the Administrative Agent and the Lenders to enter into this Agreement and to make the Loans, each Registrant, on behalf of each Borrower that is a series thereof, hereby represents and warrants to the Administrative Agent and each Lender that (it being agreed that each Registrant represents and warrants only to matters with respect to itself, if applicable, and each Borrower that is a series thereof):

3.1 Financial Condition. For each Borrower, the statement of assets and liabilities as of such Borrower’s most recently ended fiscal year for which annual reports have been prepared and the related statements of operations and of changes in net assets for the fiscal year ended on such date, copies of which financial statements, certified by the independent public accountants for such Borrower, have heretofore been delivered to each Lender, fairly present, in all material respects, the financial position of such Borrower as of such date and the results of its operations for such period, in conformity with GAAP (as consistently applied).

3.2 No Change. For each Borrower, since the date of the statement of assets and liabilities for the most recently ended fiscal year for which annual reports have been prepared for such Borrower (such date, the “Reporting Date”), there has been no development or

event which has had or could reasonably be expected to have a Material Adverse Effect with respect to such Borrower.

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3.3 Existence; Compliance with Law. Each Registrant (a) is duly organized, validly existing and in good standing, under the laws of the jurisdiction of its organization, (b) has the corporate power and authority as to those Registrants that are organized as corporations, and the trust power and authority as to those Registrants that are organized as trusts; and in each case the legal right to own its property and to conduct the business in which it is currently engaged, (c) is duly qualified as a foreign corporation or business trust and, if a corporation, is in good standing under the laws of each jurisdiction where its ownership of property or the conduct of its business requires such qualification and (d) is in compliance with all Requirements of Law (including without limitation the 1940 Act and the Securities Act), except to the extent that the failure to comply therewith could not, in the aggregate, reasonably be expected to have a Material Adverse Effect. The shares of each Fund have been validly authorized.

3.4 Power; Authorization; Enforceable Obligations. Each Registrant, acting on its own behalf and if applicable on behalf of each of its underlying series that is a Borrower, has either (i) the corporate power and authority to the extent that it is organized as a corporation or (ii) the trust power and authority to the extent that it is organized as a trust, and in each case the legal right, to execute, deliver and perform the Loan Documents to which it is a party and to borrow hereunder on behalf of each of its underlying series that is a Borrower, and has taken all necessary action to authorize the borrowings on the terms and conditions of this Agreement and any Notes and to authorize the execution, delivery and performance of the Loan Documents to which it is a party including, but not limited to, receiving the approval of the majority of independent members of the board of trustees or board of directors of each of its underlying series as to entering into the transactions contemplated hereby. No consent or authorization of, filing with, notice to or other act by or in respect of, any Governmental Authority or any other Person is required in connection with the borrowings hereunder or with the execution, delivery, performance, validity or enforceability of the Loan Documents to which such Registrant, on behalf of its underlying series which are Borrowers, is a party; provided that any filings made in connection with complying with the Investment Company Act of 1940 or the forms adopted thereunder will not result in a breach of this representation. This Agreement has been, and each other Loan Document to which a Registrant is a party will be, duly executed and delivered by such Registrant, on behalf of its underlying series that are Borrowers. This Agreement constitutes, and each other Loan Document to which a Registrant is a party when executed and delivered will constitute, a legal, valid and binding obligation of such Registrant (on behalf of each of its underlying series that is a Borrower) enforceable against such Registrant (on behalf of each of its underlying series that is a Borrower) in accordance with its terms, except as enforceability may be limited by applicable bankruptcy, insolvency, reorganization, moratorium or similar laws affecting the enforcement of creditors’ rights generally and by general equitable principles (whether enforcement is sought by proceedings in equity or at law).

3.5 No Legal Bar. The execution, delivery and performance of the Loan Documents to which each Registrant, on behalf of each of its series that is a Borrower, is a party, the borrowings hereunder and the use of the proceeds thereof (i) will not violate any material Requirement of Law (including, without limitation, the 1940 Act) or material Contractual Obligation of such Registrant or any Borrower and (ii) will not result in, or require, the creation or imposition of any material Lien on any of their respective material properties or revenues pursuant to any such Requirement of Law or Contractual Obligation.

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3.6 No Material Litigation. No litigation, investigation or proceeding of or before any arbitrator or Governmental Authority is pending or, to the knowledge of each Registrant on behalf of its respective series which are Borrowers, threatened by or against such Borrowers or against any of their respective properties or revenues (a) with respect to any of the Loan Documents or any of the transactions contemplated hereby or thereby, or (b) which could reasonably be expected to have a Material Adverse Effect.

3.7 No Default. No Registrant or Borrower is in default under or with respect to any of its Contractual Obligations in any respect that could reasonably be expected to have a Material Adverse Effect. No Default or Event of Default has occurred and is continuing.

3.8 Ownership of Property; Liens. Each Registrant on behalf of its respective series which are Borrowers, has good title to all its property, and none of such property is subject to any Lien except as permitted by Section 6.3.

3.9 No Burdensome Restrictions. There exists no Requirement of Law or Contractual Obligation of any Registrant or any Borrower which could reasonably be expected to have a Material Adverse Effect.

3.10 Taxes. Each Borrower has filed all material tax returns which, to the knowledge of such Borrower, are required to be filed and has paid all taxes shown to be due and payable on said returns or on any assessments made against it or any of its property and all other taxes, fees or other charges imposed on it or any of its property by any Governmental Authority (other than any the amount or validity of which are currently being contested in good faith by appropriate proceedings and with respect to which reserves in conformity with GAAP have been provided on the books of such Borrower); no material tax Lien has been filed, and, to the knowledge of such Borrower, no claim is being asserted, with respect to any such tax, fee or other charge.

3.11 Federal Regulations. Other than the furnishing of the statement and list referred to in the last sentence of Section 5.8, no filing or other action is required under the provisions of Regulations T, U or X in connection with the execution and delivery of this Agreement and the other Loan Documents and the making of the Loans hereunder. No part of the proceeds of any Loans made hereunder will be used in a manner that violates Regulation U.

3.12 ERISA. Neither any Registrant, any Borrower nor any Commonly Controlled Entity has currently or has had at any time any liability or obligation under ERISA or the Code with respect to any Plan maintained by any of them that could reasonably be expected to have a Material Adverse Effect.

3.13 Certain Regulations. Neither any Registrant nor any Borrower is subject to regulation under any Federal or State statute or regulation (other than Regulations U and X) which limits its ability to incur Indebtedness, or if so subject is in compliance with such statutes and regulations.

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3.14 Subsidiaries. No Borrower that is not a Cayman Parent Borrower or a Mauritius Parent Borrower has any Subsidiaries or any equity investment or interest in any other Person (other than portfolio securities that have been acquired in the ordinary course of business). Each Cayman Parent Borrower has no Subsidiaries or any equity investment or interest in any other Person other than (i) portfolio securities that have been acquired in the ordinary course of business, and (ii) its Cayman Designated Subsidiary(ies). Each Cayman Parent Borrower holds all of the issued and outstanding shares of stock of its Cayman Designated Subsidiary(ies) and such shares are not subject to any Lien, pledge or other encumbrance except as may be permitted by Section 6.3.

3.15 Registration of the Fund. Each Registrant is a registered open-end management investment company under the 1940 Act.

3.16 Offering in Compliance with Securities Laws. Each Registrant has issued all of its securities pursuant to an effective Registration Statement on Form N-1A or as may otherwise be required by Federal and State securities laws applicable thereto in all material respects.

3.17 Investment Policies. Each Borrower is in compliance in all material respects with all of its fundamental Investment Policies.

3.18 Permission to Borrow. Each Borrower is permitted to borrow hereunder pursuant to the limits and restrictions set forth in its Prospectus.

3.19 Accuracy of Information; Electronic Information. (a) All factual information heretofore or contemporaneously furnished by or on behalf of each Fund or Registrant on behalf of its respective series which are Borrowers, in writing to the Administrative Agent or any Lender for purposes of or in connection with this Agreement or any transaction contemplated hereby (in each case, as amended, superseded, supplemented or otherwise modified with the knowledge of the Administrative Agent or such Lender) is, and all other such factual information hereafter furnished by or on behalf of such Registrant and such Borrowers to the Administrative Agent or any Lender (in each case, as amended, superseded, supplemented or otherwise modified with the knowledge of the Administrative Agent or such Lender) will be, true and accurate in every material respect on the date as of which such information is dated or certified, and to the extent such information was furnished to the Administrative Agent or such Lender heretofore or contemporaneously, as of the date of execution and delivery of this Agreement by the Administrative Agent or such Lender, and such information is not, or shall not be, as the case may be, incomplete by omitting to state any material fact necessary to make such information not misleading.

(b) Neither the Administrative Agent nor any Lender shall be liable to any Registrant or Borrower for any damages arising from its respective use of information or other materials obtained through electronic, telecommunications or other information transmission systems, which is incorrect or incomplete solely because of an electronic transmission error, provided that the Administrative Agent and the Lenders use reasonable industry standard-safeguards to prevent the unauthorized dissemination of such information or other materials through such electronic, telecommunications or other information transmission systems.

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3.20 Affiliated Persons. (a) To the best knowledge of each Registrant, such Registrant, and if applicable each series thereof that is a Borrower, is not an “affiliated person” (as defined in the 1940 Act) of the Administrative Agent or any Lender, except with respect to (i) the Affected Borrowers’ relationship with each respective Bank-Advisor and (ii) the Referenced Borrowers’ (as defined below) relationship with certain BANA Entities (as defined below); provided, however, that for purposes of this Section 3.20, (A) the record ownership, without the power to vote, of five percent or more of the outstanding voting securities of any Person shall be deemed not to constitute the direct or indirect ownership of, control of, or holding with the power to vote of, such securities, and (B) securities of such Borrower held of record by the Administrative Agent or any Lender shall be deemed conclusively, absent written notice to the contrary, to be held without the power to vote such securities.

(b) Certain divisions or affiliates of Bank of America, N.A. (“BANA”), including U.S. Trust, the trust department of BANA (collectively, the “BANA Entities”) may hold record ownership of five percent or more of the outstanding voting securities of certain Borrowers (the “Referenced Borrowers”) in non-proprietary, trust or other fiduciary accounts (the “Fiduciary Accounts”) in the relevant BANA Entity’s capacity as a fiduciary for the respective principals or beneficiaries of the Fiduciary Accounts. Each Registrant acting on behalf of a Referenced Borrower that is a series thereof, on behalf of such Referenced Borrower hereby represents and warrants to the Administrative Agent and each Lender that (it being agreed that such Registrant represents and warrants only to matters with respect to itself, if applicable, and each Referenced Borrower that is a series thereof) neither the 1940 Act, including without limitation Section 17(a)(4) thereof, nor any rule or regulation promulgated thereunder, prohibits the making of any Loan by Bank of America, N.A. to such Referenced Borrower.

3.21 Anti-Corruption Laws and Sanctions. Each Borrower has implemented and maintains in effect policies and procedures designed to ensure compliance by such Borrower, its Subsidiaries and their respective directors, officers, employees and agents with Anti-Corruption Laws and applicable Sanctions, and each Borrower, its Subsidiaries and their respective officers, directors and employees and to the knowledge of such Borrower, its affiliates and agents, are in compliance with Anti-Corruption Laws and applicable Sanctions. None of (a) such Borrower, any Subsidiary of such Borrower or any of their respective directors, officers or employees, or (b) to the knowledge of such Borrower, any affiliate or agent of the Borrower or any Subsidiary of such Borrower that will act in any capacity in connection with or benefit from the credit facility established hereby, is a Sanctioned Person or is located, organized or resident in a Sanctioned Country. No Loan, use of proceeds of any Loan or other transaction contemplated by this Agreement will violate Anti-Corruption Laws or applicable Sanctions.

3.22 Affected Financial Institutions. No Registrant or Borrower is an Affected Financial Institution.

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SECTION 4. CONDITIONS PRECEDENT

4.1 Conditions to Closing. The agreement of each Lender to enter into this Agreement is subject to the satisfaction of the following conditions precedent (it being agreed that each Registrant need only satisfy the following conditions precedent with respect to itself and if applicable each Borrower that is a series thereof):

(a) Executed Agreement. The Administrative Agent shall have received this Agreement, executed and delivered by a duly authorized officer of each Registrant on behalf of its respective Funds which are Borrowers, with a counterpart for each Lender (which, subject to Section 9.9(b), may include any Electronic Signatures transmitted by telecopy, emailed pdf. or any other electronic means that reproduces an image of an actual executed signature page).

(b) Related Agreements. The Administrative Agent shall have received, with a copy for each Lender, true and correct copies, certified as to authenticity by a Responsible Officer of each Registrant, on behalf of the series thereof which are Borrowers, of (i) designation of the location where the most recent Prospectus is publicly available for each Borrower, and upon the request of any Lender, a copy of any such Prospectus, (ii) the Custody Agreement of each Registrant, with respect to each Borrower, (iii) the Investment Management Agreement of each Registrant, with respect to each Borrower, (iv) the current Statement of Additional Information for each Borrower and (v) if requested by the Lenders, designations of the locations of the most recent annual and semi-annual financial reports for each Borrower and such other documents or instruments as may be reasonably requested by the Administrative Agent, including, without limitation, a copy of any debt instrument, security agreement or other material contract to which any Borrower may be a party.

(c) Proceedings of the Registrant and the Borrowers. The Administrative Agent shall have received, with a counterpart for each Lender, a copy of the resolutions, in form and substance satisfactory to the Administrative Agent, of the board of trustees or directors, as the case may be, of each Registrant, on behalf of the series thereof which are Borrowers, authorizing (i) the execution, delivery and performance of this Agreement and the other Loan Documents to which each Registrant, on behalf of the series thereof which are Borrowers, is a party and (ii) the borrowings contemplated hereunder, or such other resolutions as the Administrative Agent may approve, certified by a Responsible Officer of such Registrant as of the Closing Date, which certificate shall be in form and substance satisfactory to the Administrative Agent and shall state that the resolutions thereby certified have not been amended, modified, revoked or rescinded and are in full force and effect.

(d) Incumbency Certificate. The Administrative Agent shall have received, with a counterpart for each Lender, a Certificate of each Registrant, on behalf of the series thereof which are Borrowers, dated the Closing Date, as to the incumbency and signature of the officers of such Registrant executing any Loan Document executed by a Responsible Officer of such Registrant, satisfactory in form and substance to the Administrative Agent.

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(e) Organizational Documents. The Administrative Agent shall have received copies of each Registrant’s articles of incorporation or declaration of trust, as applicable, and Bylaws, certified as of the Closing Date as complete and correct copies thereof by a Responsible Officer of such Registrant, including without limitation those organizational documents establishing the series thereof which are Borrowers, as applicable.

(f) Legal Opinions. The Administrative Agent shall have received, with a counterpart for each Lender, the executed legal opinion of general counsel to each Registrant and each of its underlying series which is a Borrower, in a form acceptable to the Administrative Agent. Such legal opinion shall include a New York law enforceability opinion and shall cover such other matters incident to the transactions contemplated by this Agreement as the Administrative Agent or any Lender may reasonably require.

(g) Financial Information. The Administrative Agent shall have received, with a copy for each Lender, the most recent publicly available financial information of the kind described in Sections 5.1 and 5.2 of this Agreement (which includes a list of portfolio securities) for each Borrower.

(h) Termination of other Credit Facilities. All credit facilities between the Lenders and any Borrower, other than the credit facility evidenced by this Agreement, shall have been terminated.

(i) KYC. Following its request therefor, each Lender shall have received the documentation and other information that is required by regulatory authorities under applicable “know your customer” and anti-money-laundering rules and regulations, including, without limitation, the USA Patriot Act (Title III of Pub. L. 107-56 (signed into law October 26, 2001)).

4.2 Conditions to Each Loan. The agreement of each Lender to make any Loan requested by a particular Registrant on behalf of any of its respective Funds, to be made by it on any date (including, without limitation, its initial Loan) is subject to the satisfaction of the following conditions precedent:

(a) Representations and Warranties. Each of the representations and warranties (other than the representations and warranties contained in Section 3.2) made by a Registrant, on its own behalf and on behalf of each series thereof which is a Borrower, in or pursuant to the Loan Documents shall be true and correct in all material respects (or, in the case of such representations and warranties that are already qualified by materiality, in all respects) on and as of such date as if made on and as of such date.

(b) No Default. No Default or Event of Default shall have occurred with respect to the requesting Registrant, on its own behalf or on behalf of the series thereof which is a Borrower, and be continuing on such date or after giving effect to the Loans requested to be made on such date.

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(c) Maximum Borrowing Limitation. After giving effect to the proposed Loans to be made, the Asset Coverage Ratio for all borrowings of such Borrower (x) if not a Designated Borrower shall not be less than 300% and (y) if a Designated Borrower shall not be less than its applicable Designated Borrower Asset Coverage Ratio Percentage; and the requesting Borrower shall not have violated any Requirements of Law (except such violations as could not reasonably be expected to have a Material Adverse Effect) or exceeded the borrowing limits set forth in its Prospectus and/or Registration Statement or the 1940 Act.

(d) Regulation U; Form U-1. The Lenders shall be satisfied that the Loans and the use of proceeds thereof comply in all respects with Regulation U. To the extent required by Regulation U, the Administrative Agent shall have received a copy of either (i) FR Form U-1, duly executed and delivered by each Registrant on behalf of the series thereof which are Borrowers and completed for delivery to each Lender, in form acceptable to the Administrative Agent, or (ii) a current list of the assets of each Borrower (including all “margin stock” (as defined in Regulation U) from each Borrower), in form acceptable to the Administrative Agent and in compliance with Section 221.3(c)(2) of Regulation U.

(e) Additional Matters. All corporate and other proceedings, and all documents, instruments and other legal matters in connection with the transactions contemplated by this Agreement and the other Loan Documents shall be satisfactory in form and substance to the Administrative Agent, and the Administrative Agent shall have received such other documents and legal opinions in respect of any aspect or consequence of the transactions contemplated hereby or thereby as it shall reasonably request.

Each borrowing by a Borrower hereunder shall constitute a representation and warranty by the Registrant of which such Borrower is a series, on its own behalf and on behalf of such Borrower, as of the date thereof that the conditions contained in this Section have been satisfied with respect to such Borrower, and the Registrant of which it is a series if applicable.

4.3 Lender Deliverables. Each Lender shall prior to the Closing Date deliver to Columbia Management and the Administrative Agent (A) if such Lender is organized under the laws of a jurisdiction outside the United States of America, two duly completed copies of United States Internal Revenue Service Form W-8BEN-E, Form W-8IMY or Form W-8ECI, or successor applicable forms, appropriate for such Lender, or (B) if such Lender is organized under the laws of a jurisdiction within the United States of America, an Internal Revenue Service Form W-9, or successor form.

SECTION 5. AFFIRMATIVE COVENANTS

Each Registrant, on behalf of the series thereof which are Borrowers, hereby agrees that, so long as (i) the Commitments remain in effect with respect to it or any Borrower or (ii) any amount is owing by it on behalf of any Borrower to any Lender or the Administrative Agent hereunder or under any other Loan Document, it on behalf of any Borrower that is a series of such Registrant shall (it being agreed that such Registrant covenants only to matters with respect to each Borrower that is a series thereof):

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5.1 Financial Statements. Furnish to the Administrative Agent (with copies for each Lender):

(a) as soon as available and in any event within 75 days after the end of each fiscal year of such Borrower, a statement of assets and liabilities of such Borrower as at the end of such fiscal year, a statement of operations for such fiscal year, a statement of changes in net assets for such fiscal year and the preceding fiscal year, a portfolio of investments as at the end of such fiscal year and the per share and other data for such fiscal year prepared in accordance with GAAP (as consistently applied) and all regulatory requirements, and all presented in a manner acceptable to the Securities and Exchange Commission or any successor or analogous Governmental Authority and acceptable to PricewaterhouseCoopers LLP or any other independent certified public accountants of recognized standing (with respect to any Borrower, the foregoing obligation may be satisfied by such Borrower’s making publicly available its annual report (in printable format) on the website indicated for such Borrower on Schedule 5.1 (Borrowers for whom no website is indicated shall deliver such documents as aforesaid));

(b) as soon as available and in any event within 75 days after the close of the first six-month period of each fiscal year of such Borrower, a statement of assets and liabilities as at the end of such six-month period, a statement of operations for such six-month period, a statement of changes in net assets for such six-month period and a portfolio of investments as at the end of such six-month period, all prepared in accordance with regulatory requirements and all certified pursuant to such Borrower’s quarterly filings with the Securities and Exchange Commission on Form N-CSR (subject to normal year-end adjustments) as to fairness of presentation and GAAP (as consistently applied) by a Responsible Officer (with respect to any Borrower, the foregoing obligation may be satisfied by such Borrower’s making publicly available its semi-annual report (in printable format) on the website indicated for such Borrower on Schedule 5.1 (Borrowers for whom no website is indicated shall deliver such documents as aforesaid)); and

(c) On the last Business Day of each March, June, September and December, (each a “Quarterly Date”), unless previously delivered, the net asset value sheet of such Borrower as of the end of such Borrower’s most recently ended annual and semi-annual accounting periods (unless such accounting period shall have ended less than sixty days prior to such Quarterly Date, in which case such statements shall be delivered on the next Quarterly Date), certified by a Responsible Officer as being fairly stated in all material respects (with respect to any Borrower, the foregoing obligation may be satisfied by such Borrower’s making publicly available its quarterly report (in printable format) on the website indicated for such Borrower on Schedule 5.1 (Borrowers for whom no website is indicated shall deliver such documents as aforesaid)); provided, however, that if any Borrower has Loans outstanding, such Borrower shall provide to the Administrative Agent for each Lender (i) such net asset value sheet described above in this Section and (ii) a certificate of a Responsible Officer showing in reasonable detail the calculations supporting such Borrower’s compliance with Section 6.1, within two Business Days after the end of each calendar week so long as any Loans to such Borrower remain outstanding;

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all such financial statements to be complete and correct in all material respects and to be prepared in reasonable detail and in accordance with GAAP applied consistently throughout the periods reflected therein and with prior periods (except as approved by such accountants or officer, as the case may be, and disclosed therein).

5.2 Certificates; Other Information. Furnish to the Administrative Agent (with copies for each Lender):

(a) concurrently with the delivery of the financial statements referred to in Sections 5.1(a), (b) and (c), a certificate of a Responsible Officer stating that (i) to the best of such Responsible Officer’s knowledge, such Borrower during such period has observed or performed all of its covenants and other agreements, and satisfied every condition, contained in this Agreement and the other Loan Documents to be observed, performed or satisfied by it, and (ii) no Default or Event of Default has occurred and is continuing except as specified in such certificate;

(b) within five days after they are sent, copies of all financial statements and reports which each Borrower sends to its investors other those documents described in Section 5.1(a) or (b), and within five Business Days after they are filed, copies of all financial statements and reports which each Borrower may make to, or file with, the Securities and Exchange Commission or any successor or analogous Governmental Authority other than those described in Section 5.1(a) or 5.1(b) or any report or filing that is publicly available on the Securities and Exchange Commission’s website, unless reasonably requested by the Administrative Agent; and

(c) promptly, such additional financial and other information as any Lender may from time to time reasonably request, including, but not limited to, the current Registration Statement for each Borrower and copies of all changes to each Borrower’s Prospectus and Registration Statement.

5.3 Payment of Obligations. Pay, discharge or otherwise satisfy at or before maturity or before they become delinquent (beyond any allowable grace periods therefor), as the case may be, all such Borrower’s Contractual Obligations, except where (i) the amount or validity thereof is currently being contested in good faith by appropriate proceedings and reserves in conformity with GAAP with respect thereto have been provided on the books of such Borrower, as the case may be, or (ii) the failure to timely make payment thereof could not reasonably be expected to have a Material Adverse Effect.

5.4 Conduct of Business and Maintenance of Existence. Except as otherwise permitted herein, continue to engage in (i) such Borrower’s investment business in accordance with its Investment Policies, Prospectus and Registration Statement and preserve, renew and keep in full force and effect its existence and (ii) take all reasonable action to maintain all rights, privileges and franchises necessary or desirable in the normal conduct of its business except to the extent that failure to take such actions could not, in the aggregate, be reasonably expected to

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have a Material Adverse Effect; comply with all Contractual Obligations and Requirements of Law except to the extent that failure to comply therewith could not, in the aggregate, be reasonably expected to have a Material Adverse Effect; maintain at all times its status as an investment company registered under the 1940 Act; maintain at all times its (a) current custodian, or (b) a replacement custodian which (x) is JPMorgan Chase Bank, N.A. or (y) is a bank or trust company organized under the laws of the United States or a political subdivision thereof having assets of at least $10,000,000,000 and a long-term debt or deposit rating of at least A from S&P or A2 from Moody’s; maintain in effect and enforce policies and procedures designed to ensure compliance by such Borrower, such Borrower’s Subsidiaries and their respective directors, officers, employees and agents with Anti-Corruption Laws and applicable Sanctions.

5.5 Maintenance of Property; Insurance. Keep all property useful and necessary in such Borrower’s business, if any, in good working order and condition; maintain with financially sound and reputable insurance companies insurance on all its property in at least such amounts and against at least such risks as are customarily insured against in the same general area by entities engaged in the same or similar business or as may otherwise be required by the Securities and Exchange Commission or any successor or analogous Governmental Authority (including, without limitation, (a) fidelity bond coverage as shall be required by Rule 17g-1 promulgated under the 1940 Act or any successor provision and (b) errors and omissions insurance); and furnish to each Lender, upon written request, full information as to the insurance carried.

5.6 Inspection of Property; Books and Records; Discussions. Keep proper books of records and account in which full, true and correct entries in conformity with GAAP and all material Requirements of Law shall be made of all dealings and transactions in relation to its business and activities; and permit representatives of (i) the Administrative Agent, upon its own discretion or at the reasonable request of any Lender, and (ii) upon the occurrence and during the continuance of an Event of Default, any Lender, to visit and inspect any of such Borrower’s properties and examine any of its books and records during normal business hours and to discuss the business, operations, properties and financial and other condition of such Borrower with officers and employees of such Borrower and with its independent certified public accountants; provided that, unless a Default or an Event of Default shall have occurred and be continuing, the Administrative Agent shall provide the Borrowers with five Business Days’ prior notice of such visit and shall conduct such visit not more than once a year.

5.7 Notices. Promptly give notice to the Administrative Agent and each Lender of:

(a) the occurrence of any Default or Event of Default with respect to such Borrower;

(b) any (i) default or event of default under any Contractual Obligation of such Borrower or (ii) litigation, investigation or proceeding which may exist at any time between such Registrant, on behalf of the series thereof which are Borrowers and any Governmental Authority, which in either case, if not cured or if adversely determined, as the case may be, could reasonably be expected to have a Material Adverse Effect;

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(c) any litigation or proceeding affecting such Borrower, or the Registrant of which it is a series, in which (i) the amount reasonably determined to be at risk is more than 5% of such Borrower’s net assets and not covered by insurance or in which injunctive or similar relief affecting more than 5% of such Borrower’s net assets is sought or (ii) relates to this Agreement or the credit facility contemplated hereby;

(d) any change in such Borrower’s Prospectus or Registration Statement involving Investment Policies which could materially increase the risks to the shareholders of the Borrower or which would increase the borrowing limits provided for in such Borrower’s Prospectus;

(e) any development or event which could reasonably be expected to have a Material Adverse Effect on such Borrower;

(f) any change in such Borrower’s custodian, unless such custodian is JPMorgan Chase Bank, N.A., in which case no notice is required to be sent; and

(g) any name change affecting any Borrower after the effectiveness of such name change, together with updated tax forms and other “know your customer” information requested by the Administrative Agent or any Lender.

Each notice pursuant to this Section shall be accompanied by a statement of a Responsible Officer setting forth details of the occurrence referred to therein and if appropriate stating what action such Registrant or such Borrower proposes to take with respect thereto.

5.8 Purpose of Loans. Use the proceeds of the Loans for temporary or emergency purposes, including, without limitation, funding of shareholder redemptions or the payment of dividends (i) which are required by law or in connection with the maintenance of such Borrower’s tax status or (ii) for the purpose of avoiding imposition of federal excise tax. Without limiting the foregoing, no Borrower will, directly or indirectly, use any part of such proceeds for any purpose which would violate any provision of its Registration Statement or any applicable statute, regulation, order or restriction, including but not limited to Regulation U; provided, however, that neither the Administrative Agent nor any Lender shall have any responsibility as to the use of any of such proceeds. If requested by any Lender or the Administrative Agent from time to time, each Registrant, on behalf of the series thereof which are Borrowers, will furnish to the Administrative Agent and each Lender a statement and current list of the assets of each Borrower in conformity with the requirements of FR Form U-1 referred to in Regulation U.

5.9 Payment of Taxes. File all material tax returns which, to the knowledge of such Registrant and such Borrowers, are required to be filed and pay all taxes shown to be due and payable on said returns or on any assessments made against it or any of its property and all other taxes, levies, fees or other charges imposed on it or any of its property by any Governmental Authority; provided, however, that no such tax, assessment, charge or levy need be paid and discharged so long as the validity thereof shall be contested in good faith by appropriate proceedings and there shall have been set aside on the books of such Person adequate reserves in accordance with GAAP applied with respect thereto.

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SECTION 6. NEGATIVE COVENANTS

Each Registrant, on behalf of the series thereof which are Borrowers, hereby agrees that, so long as (i) the Commitments remain in effect with respect to any such Borrower or (ii) any amount is owing by any such Borrower to any Lender or the Administrative Agent hereunder or under any other Loan Document, it and any such Borrower shall not, without the prior written consent of the Lenders except as otherwise specified in this Section 6, directly or indirectly (it being agreed that each Registrant agrees only to matters with respect to each Borrower that is a series thereof):

6.1 Financial Condition Covenant. Permit the Asset Coverage Ratio of such Borrower to be less than (x) for all Borrowers other than Designated Borrowers, 300%, or (y) for each Designated Borrower, the Designated Borrower Asset Coverage Ratio Percentage for such Borrower; or in either case allow borrowings and/or Indebtedness of such Borrower to exceed the limits set forth in such Borrower’s Prospectus or allow borrowings and/or Indebtedness to exceed the requirements of the 1940 Act.

6.2 Limitation on Indebtedness; Derivatives. (a) Create, incur, assume or suffer to exist any Indebtedness of such Borrower or any Subsidiary, except Indebtedness of such Borrower or Subsidiary incurred (i) under this Agreement and the Notes, (ii) in the ordinary course of business of such Borrower or such Subsidiary, (iii) pursuant to an Interfund Lending arrangement, (iv) with respect to Indebtedness of a Cayman Designated Subsidiary or a Mauritius Designated Subsidiary, in accordance with its articles of association and other related organizational documents, or (v) in the form of Reverse Repurchase Transactions, dollar rolls or other transactions entered into primarily for investment purposes which have the effect of borrowing and, in each case, which is not otherwise prohibited by law, is in the ordinary course of business, is not in contravention of such Borrower’s Prospectus and is reflected properly in the calculation of the Asset Coverage Ratio.

(b) Invest in, or incur Indebtedness or other liability to any Person with respect to, any Swap Obligation or derivative instrument (including without limitation any swap, collar, cap, puts, calls, equity derivative or mortgage-backed or debt-backed derivative) unless each of the following is true: (i) the net mark-to-market value of such Swap Obligation or derivative instrument is appropriately reflected in the calculation of Asset Coverage Ratio, and (ii) the purpose of the investment in such Swap Obligation or derivative instrument is to augment the capital appreciation or current income of or by such Borrower, or to hedge or manage the risk of various current or future exposures of such Borrower.

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6.3 Limitation on Liens. Create, incur, assume or suffer to exist any Lien upon any of the property, assets or revenues, whether now owned or hereafter acquired of such Borrower, except for (i) Liens for taxes not yet due or which are being contested in good faith by appropriate proceedings, provided that adequate reserves with respect thereto are maintained on the books of such Borrower in conformity with GAAP, (ii) Liens arising in connection with claims for advances made by or payments due to any custodian under the Custody Agreements set forth in Schedule IV, (iii) Liens arising from any Prime Broker Agreement set forth in Schedule V, (iv) Liens created, incurred, assumed or suffered to exist in compliance with the Registration Statement or organizational documents of such Borrower, (v) Liens arising under an Interfund Lending arrangement, and (vi) any other Liens created, incurred, assumed or suffered to exist in the ordinary course of such Borrower’s business, and which, in each case, are not otherwise prohibited by any Requirement of Law.

6.4 Limitation on Guarantee Obligations. Create, incur, assume or suffer to exist any material Guarantee Obligation of such Borrower, except as may occur in the ordinary course of such Borrower’s business and which is not otherwise prohibited by any Requirement of Law. In no event may a Mauritius Parent Borrower or Cayman Parent Borrower create, incur, assume or suffer to exist any material Guarantee Obligation in respect of the Indebtedness of any of their respective Subsidiaries.

6.5 Limitation on Fundamental Changes. Enter into, or permit any of its Subsidiaries to enter into, any merger, consolidation or amalgamation, or liquidate, wind up or dissolve itself or such Borrower (or suffer any liquidation or dissolution), or convey, sell, lease, assign, transfer or otherwise dispose of substantially all of the property, business or assets of itself, such Borrower, or such Subsidiary in a single transaction or in related transactions, or make any material change in its present method of conducting business; except that, so long as no Default or Event of Default shall have occurred and be continuing, a Borrower will be permitted to (i) without the consent of the Lenders, enter into any merger, consolidation or amalgamation with one or more Borrowers or, with the consent of the Lenders, enter into any merger, consolidation or amalgamation with one or more other Persons if, in each case, Columbia Management or one of its affiliates is the investment advisor to the entity surviving such merger, consolidation or amalgamation and such entity assumes the obligations of such Borrower under the Loan Documents and complies with Applicable Law and with the provisions hereof or (ii) terminate all Commitments with respect to such Borrower and liquidate, wind up or convey, sell, lease, assign, transfer or otherwise dispose of all or substantially all of the property, business or assets of such Borrower if it repays all Loans made to it prior to liquidation, together with all other amounts due and owing hereunder. Any Borrower undertaking any action described in clause (ii) above shall comply with the termination provisions described in Section 2.4.

6.6 Limitation on Distributions. At any time, make any distribution to the shareholders (including, without limitation, any dividends or any repurchase of capital interests) of such Borrower, whether now or hereafter existing, either directly or indirectly, whether in cash or property or in obligations of the Borrower if such distribution results in a Default or Event of Default. During the occurrence and continuation of an Event of Default specified in paragraphs (a) or (e) of Section 7 or an Event of Default arising in connection with a Borrower’s having failed to comply with Section 6.1, make any distribution to the shareholders (including, without limitation, any dividends or any repurchase of capital interests) of such Borrower, whether now or hereafter existing, either directly or indirectly, whether in cash or property or in obligations of such Borrower. Notwithstanding the foregoing, nothing herein shall prevent a Borrower from making (i) distributions that are required to enable such Borrower to qualify as a “regulated investment company” under Sections 851-855 of the Code or otherwise to minimize or eliminate federal or state income or excise taxes payable by such Borrower, or (ii) distributions that are required by any other Requirement of Law.

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6.7 Limitation on Investments, Loans and Advances. Make any advance, loan, extension of credit or capital contribution to, or purchase any stock, bonds, notes, debentures or other securities of or any assets constituting a business unit of or make any other investment in, any Person, except those consistent with such Borrower’s Investment Policies.

6.8 Limitation on Transactions with Affiliates. Enter into any transaction, including, without limitation, any purchase, sale, lease or exchange of property or the rendering of any service, with any Affiliate unless such transaction is (a) not otherwise prohibited under this Agreement and not in violation of the 1940 Act, (b) in the ordinary course of such Borrower’s business, and (c) upon fair and reasonable terms no less favorable to such Borrower than it would obtain in a comparable arm’s length transaction with a Person which is not an Affiliate.

6.9 Limitation on Negative Pledge Clauses. Enter into with any Person any agreement, other than this Agreement or the other Loan Documents, which prohibits or limits the ability of such Borrower to create, incur, assume or suffer to exist any Lien upon any of its property, assets or revenues, whether now owned or hereafter acquired, other than (i) this Agreement or the other Loan Documents or (ii) except as may occur under agreements entered into in the ordinary course of such Borrower’s business and which are not otherwise prohibited by any Requirement of Law.

6.10 Limitation on Changes to Investment Policies. Except as may be required by law, make any amendment to the Prospectus or Registration Statement of such Borrower (i) relating to changes in the fundamental Investment Policies of such Borrower, or (ii) increasing the borrowing limits specified therein, in each case without the consent of the Required Lenders, which consent shall not be unreasonably withheld.

6.11 Cayman Parent Borrower Activities. If it is a Cayman Parent Borrower, such Borrower will not (a) permit its Cayman Designated Subsidiary to engage in any business or activity other than that permitted under the Cayman Parent Borrower’s Prospectus or (b) itself engage in any business or activity other than (i) acting as a holding company for its Cayman Designated Subsidiary and (ii) acting as a registered open-end investment company under the 1940 Act.

6.12 Cayman Parent Borrower Sale of Assets, Etc. If it is a Cayman Parent Borrower, such Borrower will not permit its Cayman Designated Subsidiary to (a) merge into or consolidate with any Person other than such Cayman Parent Borrower or another Borrower hereunder, or (b) sell, transfer, lease or otherwise dispose of (in one transaction or in a series of transactions) all or substantially all of its assets (whether now owned or hereafter acquired), except for assets sold or disposed of in the ordinary course of business and except for any such transfers to such Cayman Parent Borrower or another Borrower hereunder.

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6.13 Prohibited Use of Proceeds. Each Borrower shall not request any Loan, and each Borrower shall not, directly or indirectly, use, and shall procure that its Subsidiaries and its or their respective directors, officers, employees and agents shall not use, the proceeds of any Loan, or lend, contribute or otherwise make available such proceeds to any Person (A) in furtherance of an offer, payment, promise to pay, or authorization of the payment or giving of money, or anything else of value, to any Person in violation of any Anti-Corruption Laws, (B) for the purpose of funding, financing or facilitating any activities, business or transaction of or with any Sanctioned Person, or in any Sanctioned Country, or (C) in any manner that would result in the violation of any Sanctions by any Person, including Sanctions applicable to any party hereto.

SECTION 7. EVENTS OF DEFAULT

Subject to the final paragraph of this Section 7, if any of the following events shall occur and be continuing with respect to any Registrant, on its own behalf or on behalf of the series thereof which are Borrowers, as the case may be (each an “Event of Default”):

(a) A Borrower shall fail to pay any principal of any Loan when due in accordance with the terms thereof or hereof, including without limitation any failure to make a mandatory prepayment due pursuant to the provisions of Section 2.6(b); or a Borrower shall fail to pay any interest on any Loan, or any other amount payable hereunder, within five days after any such interest or other amount becomes due in accordance with the terms thereof or hereof; or

(b) Any representation or warranty made or deemed made by any Registrant, on its own behalf or on behalf of the series thereof which are Borrowers, or made or deemed made at such Registrant’s or Borrower’s request, herein or in any other Loan Document or which is contained in any certificate, document or financial or other statement furnished by it at any time under or in connection with this Agreement or any such other Loan Document shall prove to have been incorrect in any material respect on or as of the date made or deemed made; or

(c) A Registrant, on its own behalf or on behalf of the series thereof which are Borrowers, shall default in the observance or performance of (i) Section 6.13 or (ii) any other agreement contained in this Agreement or any other Loan Document (other than as provided in paragraphs (a) and (b) of this Section), and such default shall continue unremedied for a period of 30 days; or solely in the case of such default arising under Sections 5.4, 5.7 or 6.5, 5 Business Days; or solely in the case of such default arising under Section 5.2(b), 10 days from the delivery of notice thereof by the Administrative Agent to such Registrant (unless the Administrative Agent shall have reasonably determined that the non-delivery of information giving rise to such default under Section 5.2(b) shall have materially impaired the rights of the Lenders hereunder, in which case such default shall ripen into an Event of Default if unremedied after the earlier of 10 days from delivery of notice or 30 days after the occurrence thereof); or

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(d) A Registrant, or on behalf of any series thereof which is a Borrower, shall (i) default in any payment of principal of or interest on any Indebtedness (other than the Loans), Interest Rate Agreement or Swap Obligation or in the payment of any Guarantee Obligation, beyond the grace period (not to exceed 30 days), if any, provided in the instrument or agreement under which such Indebtedness, Interest Rate Agreement, Swap Obligation or Guarantee Obligation was created, if the aggregate amount of the Indebtedness or amount owing under an Interest Rate Agreement, Swap Obligation and/or Guarantee Obligations in respect of which such default or defaults shall have occurred is at least 5% of such Borrower’s net assets, calculated on a net mark-to-market basis for Interest Rate Agreements and Swap Obligations; or (ii) default in the observance or performance of any other agreement or condition relating to any such Indebtedness, Interest Rate Agreement, Swap Obligation or Guarantee Obligation or contained in any instrument or agreement evidencing, securing or relating thereto, or any other event shall occur or condition exist, the effect of which default or other event or condition is to cause, or to permit the holder or holders of such Indebtedness or beneficiary or beneficiaries of such Guarantee Obligation, Interest Rate Agreement, or Swap Obligation (or a trustee or agent on behalf of such holder or holders or beneficiary or beneficiaries) to cause, with the giving of notice if required, such Indebtedness, Interest Rate Agreement or Swap Obligation to become due prior to its stated maturity or such Guarantee Obligation to become payable if the aggregate amount of the Indebtedness or amount owing under an Interest Rate Agreement, Swap Obligations and/or Guarantee Obligations subject to becoming so due or so payable is at least 5% of such Borrower’s or Registrant’s net assets, calculated on a net mark-to-market basis for Interest Rate Agreements and Swap Obligations; or

(e) (i) A Registrant, on its own behalf or on behalf of any series thereof which is a Borrower, shall commence any case, proceeding or other action with respect to itself or any such Borrower (A) under any then Applicable Law of any jurisdiction, domestic or foreign, relating to bankruptcy, insolvency, reorganization or relief of debtors, seeking to have an order for relief entered with respect to it, or seeking to adjudicate it a bankrupt or insolvent, or seeking reorganization, arrangement, adjustment, winding-up, liquidation, dissolution, composition or other relief with respect to it or its debts, or (B) seeking appointment of a receiver, trustee, custodian, conservator or other similar official for it or for all or any substantial part of its assets, or a Registrant, on its own behalf or on behalf of any series thereof which is a Borrower, shall make a general assignment for the benefit of its creditors; or (ii) there shall be commenced against such a Registrant or Borrower, any case, proceeding or other action of a nature referred to in clause (i) above which (A) results in the entry of an order for relief or any such adjudication or appointment and (B) remains undismissed, undischarged, unstayed, unvacated or unbonded pending appeal within 60 days from the entry thereof; or (iii) there shall be commenced against a Registrant, on its own behalf or on behalf of the series thereof which are Borrowers, any case, proceeding or other action seeking issuance of a warrant of attachment, execution, distraint or similar process against all or any substantial part of its assets which results in the entry of an order for any such relief which shall not have been vacated, discharged, or stayed or bonded pending appeal within 60 days from the entry thereof; or (iv) such a Registrant or Borrower shall take any action in material furtherance of, or indicating its consent to, approval of, or acquiescence in, any of the acts set forth in clause (i), (ii), or (iii) above; or (v) a Registrant, on its own behalf or on behalf of the series thereof which are Borrowers, shall not, or shall be unable to, pay its debts as they become due for ten (10) days after written notice thereof to such Registrant or actual knowledge thereof by such Registrant, or shall admit in writing its inability to pay its debts as they become due; or

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(f) Either a Borrower or any Commonly Controlled Entity of such Borrower incurs any liability to any Plan maintained by any of them which could reasonably be expected to have a Material Adverse Effect; or

(g) One or more final judgments or decrees shall be entered against a Borrower, involving in the aggregate a liability (not fully covered by insurance or otherwise paid or discharged) of 5% or more of such Borrower’s net assets, and all such judgments or decrees shall not have been vacated, discharged, stayed or bonded pending appeal within 30 days from the entry thereof; or

(h) Unless consented to by all of the Lenders, Columbia Management or a Person directly controlling, controlled by, or under common control with Columbia Management shall no longer act as investment advisor for a Borrower; or

(i) A Registrant’s registration under the 1940 Act shall lapse or be suspended (or proceedings for such purpose shall have been instituted); or

(j) A Registrant, on its own behalf or on behalf of the series thereof which are Borrowers, shall fail to materially comply with its Investment Policies in a manner which could reasonably be expected to have a Material Adverse Effect and such default (or the Material Adverse Effect arising therefrom if any) shall continue unremedied for a period of 3 days; or

(k) A Borrower shall (i) fail to materially comply with the 1940 Act or (ii) default in the observance or performance of Section 6.13.

then, and in any such event, (A) if such event is an Event of Default specified in paragraph (e) of this Section with respect to such Borrower (or the Registrant acting on behalf of one or more Borrowers), automatically the Commitments available to such Borrower (or all of the Borrowers which are series of such Registrant) shall immediately terminate and the Loans hereunder made to any such Borrower, or Borrowers as the case may be, (with accrued interest thereon) and all other amounts owing under this Agreement by such Borrower, or Borrowers, as the case may be, shall immediately become due and payable, and (B) if such event is any other Event of Default with respect to such Borrower, any or all of the following actions may be taken: (i) with the consent of the Required Lenders, the Administrative Agent may, or upon the request of the Required Lenders, the Administrative Agent shall, by notice to such Borrower declare the Commitments available to such Borrower (or all of the Borrowers which are series of such Registrant if such Event of Default is a Registrant Event of Default (as defined below)) to be terminated forthwith, whereupon such Commitments shall immediately terminate; and (ii) with the consent of the Required Lenders, the Administrative Agent may, or upon the request of the Required Lenders, the Administrative Agent shall, by notice to such Borrower, declare the Loans to such Borrower (with accrued interest thereon) and all other amounts owing under this Agreement by such Borrower (or all of the Borrowers which are series of such Registrant if such Event of Default is a Registrant Event of Default) to be due and payable forthwith, whereupon the same shall immediately become due and payable. Except as expressly provided above in this Section, presentment, demand, protest and all other notices of any kind are hereby expressly waived.

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Notwithstanding any other provision herein to the contrary, Defaults and Events of Default shall have the following results:

(i) a Default or Event of Default with respect to one Borrower shall not constitute a Default or Event of Default with respect to any other Borrower;

(ii) except as set forth in clause (iii) below, a Default or Event of Default with respect to a Registrant acting on behalf of one or more Borrowers that is a series of such Registrant shall constitute a Default or Event of Default, as the case may be, only with respect to the Borrower(s) implicated in, or affected by, the act or omission causing such Default or Event of Default;

(iii) a Registrant Default or a Registrant Event of Default (each as defined below) with respect to a Registrant acting on behalf of one or more Borrowers that is a series thereof shall constitute a Default or Event of Default, as the case may be, with respect to any Borrower that is a series thereof to the extent that such Registrant Default or Registrant Event of Default is, in the reasonable discretion of the Administrative Agent or the Required Lenders, expected to have a Material Adverse Effect on such Borrower’s ability to perform its obligations under this Agreement and the other Loan Documents; and

(iv) an Event of Default of the type described in paragraph (h) of this Section 7 shall constitute an Event of Default with respect to all Borrowers for which Columbia Management no longer acts as investment manager.

“Registrant Event of Default” shall mean an Event of Default with respect to a Registrant (A) of any of the types described in paragraphs (e) or (i) of this Section 7, or (B) arising from such Registrant’s failure to comply with the covenants set forth in Section 5.3, 5.4, 5.5 or 6.5.

“Registrant Default” shall mean any of the events giving rise to a Registrant Event of Default, whether or not any requirement for the giving of notice, the lapse of time, or both, or any other condition, has been satisfied.

SECTION 8. THE ADMINISTRATIVE AGENT

8.1 Authorization and Action.

(a) Each Lender hereby irrevocably appoints the entity named as Administrative Agent in the heading of this Agreement and its successors and assigns to serve as the administrative agent under the Loan Documents, and each Lender authorizes the Administrative Agent to take such actions as agent on its behalf and to exercise such powers

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under this Agreement and the other Loan Documents as are delegated to the Administrative Agent under such agreements and to exercise such powers as are reasonably incidental thereto. Without limiting the foregoing, each Lender hereby authorizes the Administrative Agent to execute and deliver, and to perform its obligations under, each of the Loan Documents to which the Administrative Agent is a party, to exercise all rights, powers and remedies that the Administrative Agent may have under such Loan Documents.

(b) As to any matters not expressly provided for herein and in the other Loan Documents (including enforcement or collection), the Administrative Agent shall not be required to exercise any discretion or take any action, but shall be required to act or to refrain from acting (and shall be fully protected in so acting or refraining from acting) upon the written instructions of the Required Lenders (or such other number or percentage of the Lenders as shall be necessary, pursuant to the terms in the Loan Documents), and, unless and until revoked in writing, such instructions shall be binding upon each Lender; provided, however, that the Administrative Agent shall not be required to take any action that (i) the Administrative Agent in good faith believes exposes it to liability unless the Administrative Agent receives written indemnification and is exculpated in a manner satisfactory to it from the Lenders with respect to such action or (ii) is contrary to this Agreement or any other Loan Document or applicable law, including any action that may be in violation of the automatic stay under any requirement of law relating to bankruptcy, insolvency or reorganization or relief of debtors or that may effect a forfeiture, modification or termination of property of a Defaulting Lender in violation of any requirement of law relating to bankruptcy, insolvency or reorganization or relief of debtors; provided, further, that the Administrative Agent may seek clarification or direction from the Required Lenders prior to the exercise of any such instructed action and may refrain from acting until such clarification or direction has been provided. Except as expressly set forth in the Loan Documents, the Administrative Agent shall not have any duty to disclose, and shall not be liable for the failure to disclose, any information relating to any Borrower, any Subsidiary or any Affiliate of any of the foregoing that is communicated to or obtained by the Person serving as Administrative Agent or any of its Affiliates in any capacity. Nothing in this Agreement shall require the Administrative Agent to expend or risk its own funds or otherwise incur any financial liability in the performance of any of its duties hereunder or in the exercise of any of its rights or powers if it shall have reasonable grounds for believing that repayment of such funds or adequate indemnity against such risk or liability is not reasonably assured to it.

(c) In performing its functions and duties hereunder and under the other Loan Documents, the Administrative Agent is acting solely on behalf of the Lenders (except in limited circumstances expressly provided for herein relating to the maintenance of the Register), and its duties are entirely mechanical and administrative in nature. Without limiting the generality of the foregoing:

(i) the Administrative Agent does not assume and shall not be deemed to have assumed any obligation or duty or any other relationship as the agent, fiduciary or trustee of or for any Lender or holder of any other obligation other than as expressly set forth herein and in the other Loan Documents, regardless of whether a Default or an Event of Default has occurred and is continuing (and it is understood and agreed that the use of the term “agent” (or any similar term) herein or in any other Loan Document with reference to the Administrative Agent is not intended to connote any fiduciary duty or other implied

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(or express) obligations arising under agency doctrine of any applicable law, and that such term is used as a matter of market custom and is intended to create or reflect only an administrative relationship between contracting parties); additionally, each Lender agrees that it will not assert any claim against the Administrative Agent based on an alleged breach of fiduciary duty by the Administrative Agent in connection with this Agreement and the transactions contemplated hereby; and

(ii) nothing in this Agreement or any Loan Document shall require the Administrative Agent to account to any Lender for any sum or the profit element of any sum received by the Administrative Agent for its own account.

(d) The Administrative Agent may perform any of its duties and exercise its rights and powers hereunder or under any other Loan Document by or through any one or more sub-agents appointed by the Administrative Agent. The Administrative Agent and any such sub-agent may perform any of their respective duties and exercise their respective rights and powers through their respective Related Parties. The exculpatory provisions of this Section 8 shall apply to any such sub-agent and to the Related Parties of the Administrative Agent and any such sub-agent, and shall apply to their respective activities pursuant to this Agreement.

(e) No Arranger shall have obligations or duties whatsoever in such capacity under this Agreement or any other Loan Document and shall incur no liability hereunder or thereunder in such capacity, but all such persons shall have the benefit of the indemnities provided for hereunder.

(f) In case of the pendency of any proceeding with respect to any Borrower under any Federal, state or foreign bankruptcy, insolvency, receivership or similar law now or hereafter in effect, the Administrative Agent (irrespective of whether the principal of any Loan shall then be due and payable as herein expressed or by declaration or otherwise and irrespective of whether the Administrative Agent shall have made any demand on such Borrower) shall be entitled and empowered (but not obligated) by intervention in such proceeding or otherwise:

(i) to file and prove a claim for the whole amount of the principal and interest owing and unpaid in respect of the Loans and all other Obligations that are owing and unpaid and to file such other documents as may be necessary or advisable in order to have the claims of the Lenders and the Administrative Agent (including any claim under Sections 2.3, 2.7 and 2.10) allowed in such judicial proceeding; and

(ii) to collect and receive any monies or other property payable or deliverable on any such claims and to distribute the same;

and any custodian, receiver, assignee, trustee, liquidator, sequestrator or other similar official in any such proceeding is hereby authorized by each Lender to make such payments to the Administrative Agent and, in the event that the Administrative Agent shall consent to the making of such payments directly to the Lenders, to pay to the Administrative Agent any amount due to it, in its capacity as the Administrative Agent, under the Loan Documents (including under Section 9.5). Nothing contained herein shall be deemed to authorize the Administrative Agent to authorize or consent to or accept or adopt on behalf of any Lender any plan of reorganization, arrangement, adjustment or composition affecting the Obligations or the rights of any Lender or to authorize the Administrative Agent to vote in respect of the claim of any Lender in any such proceeding.

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(g) The provisions of this Section 8 are solely for the benefit of the Administrative Agent and the Lenders, and, except solely to the extent of any Borrower’s rights to consent pursuant to and subject to the conditions set forth in this Section 8, none of the Borrowers or any Subsidiary, or any of their respective Affiliates, shall have any rights as a third party beneficiary under any such provisions.

8.2 Administrative Agent’s Reliance, Limitation of Liability, Etc.

(a) Neither the Administrative Agent nor any of its Related Parties shall be (i) liable for any action taken or omitted to be taken by such party, the Administrative Agent or any of its Related Parties under or in connection with this Agreement or the other Loan Documents (x) with the consent of or at the request of the Required Lenders (or such other number or percentage of the Lenders as shall be necessary, or as the Administrative Agent shall believe in good faith to be necessary, under the circumstances as provided in the Loan Documents) or (y) in the absence of its own gross negligence or willful misconduct (such absence to be presumed unless otherwise determined by a court of competent jurisdiction by a final and non-appealable judgment) or (ii) responsible in any manner to any of the Lenders for any recitals, statements, representations or warranties made by any Registrant or Borrower or any officer thereof contained in this Agreement or any other Loan Document or in any certificate, report, statement or other document referred to or provided for in, or received by the Administrative Agent under or in connection with, this Agreement or any other Loan Document or for the value, validity, effectiveness, genuineness, enforceability or sufficiency of this Agreement or any other Loan Document (including, for the avoidance of doubt, in connection with the Administrative Agent’s reliance on any Electronic Signature transmitted by telecopy, emailed pdf. or any other electronic means that reproduces an image of an actual executed signature page) or for any failure of any Registrant or Borrower to perform its obligations hereunder or thereunder.

(b) The Administrative Agent shall be deemed not to have knowledge of any Default unless and until written notice thereof (stating that it is a “notice of default”) is given to the Administrative Agent by a Borrower or a Lender, and the Administrative Agent shall not be responsible for or have any duty to ascertain or inquire into (i) any statement, warranty or representation made in or in connection with any Loan Document, (ii) the contents of any certificate, report or other document delivered thereunder or in connection therewith, (iii) the performance or observance of any of the covenants, agreements or other terms or conditions set forth in any Loan Document or the occurrence of any Default, (iv) the sufficiency, validity, enforceability, effectiveness or genuineness of any Loan Document or any other agreement, instrument or document, or (v) the satisfaction of any condition set forth in Section 4 or elsewhere in any Loan Document, other than to confirm receipt of items (which on their face purport to be such items) expressly required to be delivered to the Administrative Agent or satisfaction of any condition that expressly refers to the matters described therein being acceptable or satisfactory to the Administrative Agent.

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(c) Without limiting the foregoing, the Administrative Agent (i) may treat the payee of any promissory note as its holder until such promissory note has been assigned in accordance with Section 9.6, (ii) may rely on the Register to the extent set forth in Section 9.6(d), (iii) may consult with legal counsel (including counsel to a Registrant or a Borrower), independent public accountants and other experts selected by it, and shall not be liable for any action taken or omitted to be taken in good faith by it in accordance with the advice of such counsel, accountants or experts, (iv) makes no warranty or representation to any Lender and shall not be responsible to any Lender for any statements, warranties or representations made by or on behalf of any Borrower in connection with this Agreement or any other Loan Document, (v) in determining compliance with any condition hereunder to the making of a Loan that by its terms must be fulfilled to the satisfaction of a Lender, may presume that such condition is satisfactory to such Lender unless the Administrative Agent shall have received notice to the contrary from such Lender sufficiently in advance of the making of such Loan and (vi) shall be entitled to rely on, and shall incur no liability under or in respect of this Agreement or any other Loan Document by acting upon, any notice, consent, certificate or other instrument or writing (which writing may be a fax, any electronic message, Internet or intranet website posting or other distribution) or any statement made to it orally or by telephone and believed by it to be genuine and signed or sent or otherwise authenticated by the proper party or parties (whether or not such Person in fact meets the requirements set forth in the Loan Documents for being the maker thereof).

8.3 Posting of Communications.

(a) Each Borrower agrees that the Administrative Agent may, but shall not be obligated to, make any Communications available to the Lenders by posting the Communications on IntraLinks^™, DebtDomain, SyndTrak, ClearPar or any other electronic platform chosen by the Administrative Agent to be its electronic transmission system (the “Approved Electronic Platform”).

(b) Although the Approved Electronic Platform and its primary web portal are secured with generally-applicable security procedures and policies implemented or modified by the Administrative Agent from time to time (including, as of the Effective Date, a user ID/password authorization system) and the Approved Electronic Platform is secured through a per-deal authorization method whereby each user may access the Approved Electronic Platform only on a deal-by-deal basis, each of the Lenders and each Borrower acknowledges and agrees that the distribution of material through an electronic medium is not necessarily secure, that the Administrative Agent is not responsible for approving or vetting the representatives or contacts of any Lender that are added to the Approved Electronic Platform, and that there may be confidentiality and other risks associated with such distribution. Each of the Lenders and each Borrower hereby approves distribution of the Communications through the Approved Electronic Platform and understands and assumes the risks of such distribution.

(c) THE APPROVED ELECTRONIC PLATFORM AND THE COMMUNICATIONS ARE PROVIDED “AS IS” AND “AS AVAILABLE”. THE APPLICABLE PARTIES (AS DEFINED BELOW) DO NOT WARRANT THE ACCURACY OR COMPLETENESS OF THE COMMUNICATIONS, OR THE ADEQUACY OF THE APPROVED ELECTRONIC PLATFORM AND EXPRESSLY DISCLAIM LIABILITY FOR

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ERRORS OR OMISSIONS IN THE APPROVED ELECTRONIC PLATFORM AND THE COMMUNICATIONS. NO WARRANTY OF ANY KIND, EXPRESS, IMPLIED OR STATUTORY, INCLUDING ANY WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, NON-INFRINGEMENT OF THIRD PARTY RIGHTS OR FREEDOM FROM VIRUSES OR OTHER CODE DEFECTS, IS MADE BY THE APPLICABLE PARTIES IN CONNECTION WITH THE COMMUNICATIONS OR THE APPROVED ELECTRONIC PLATFORM. IN NO EVENT SHALL THE ADMINISTRATIVE AGENT, ANY ARRANGER OR ANY OF THEIR RESPECTIVE RELATED PARTIES (COLLECTIVELY, “APPLICABLE PARTIES”) HAVE ANY LIABILITY TO ANY BORROWER, ANY LENDER OR ANY OTHER PERSON OR ENTITY FOR DAMAGES OF ANY KIND, INCLUDING DIRECT OR INDIRECT, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES, LOSSES OR EXPENSES (WHETHER IN TORT, CONTRACT OR OTHERWISE) ARISING OUT OF ANY BORROWER’S, ANY LENDER’S OR THE ADMINISTRATIVE AGENT’S TRANSMISSION OF COMMUNICATIONS THROUGH THE INTERNET OR THE APPROVED ELECTRONIC PLATFORM, EXCEPT TO THE EXTENT OF DIRECT OR ACTUAL DAMAGES AS ARE DETERMINED BY A COURT OF COMPETENT JURISDICTION BY FINAL AND NONAPPEALABLE JUDGMENT TO HAVE RESULTED FROM THE GROSS NEGLIGENCE OR WILLFUL MISCONDUCT OF SUCH APPLICABLE PARTY OR RELATED PARTY THEREOF.

(d) “Communications” means, collectively, any notice, demand, communication, information, document or other material provided by or on behalf of any Borrower pursuant to any Loan Document or the transactions contemplated therein which is distributed by the Administrative Agent or any Lender by means of electronic communications pursuant to this Section, including through an Approved Electronic Platform.

(e) Each Lender agrees that notice to it (as provided in the next sentence) specifying that Communications have been posted to the Approved Electronic Platform shall constitute effective delivery of the Communications to such Lender for purposes of the Loan Documents. Each Lender agrees (i) to notify the Administrative Agent in writing (which could be in the form of electronic communication) from time to time of such Lender’s email address to which the foregoing notice may be sent by electronic transmission and (ii) that the foregoing notice may be sent to such email address.

(f) Each of the Lenders and each Borrower agrees that the Administrative Agent may, but (except as may be required by applicable law) shall not be obligated to, store the Communications on the Approved Electronic Platform in accordance with the Administrative Agent’s generally applicable document retention procedures and policies.

(g) Nothing herein shall prejudice the right of the Administrative Agent or any Lender to give any notice or other communication pursuant to any Loan Document in any other manner specified in such Loan Document.

8.4 The Administrative Agent Individually. With respect to its Commitment and Loans (including Swing Line Loans), the Person serving as the Administrative Agent shall have and may exercise the same rights and powers hereunder and is subject to the same obligations and liabilities as and to the extent set forth herein for any other Lender. The terms “Lenders”,

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“Required Lenders” and any similar terms shall, unless the context clearly otherwise indicates, include the Administrative Agent in its individual capacity as a Lender, Required Lenders or other member of a defined group, as applicable. The Person serving as the Administrative Agent and its Affiliates may accept deposits from, lend money to, own securities of, act as the financial advisor or in any other advisory capacity for and generally engage in any kind of banking, trust or other business with, any Borrower, any Subsidiary or any Affiliate of any of the foregoing as if such Person was not acting as the Administrative Agent and without any duty to account therefor to the Lenders.

8.5 Successor Administrative Agent.

(a) The Administrative Agent may resign at any time by giving thirty (30) days’ prior written notice thereof to the Lenders and the Borrowers, whether or not a successor Administrative Agent has been appointed. Upon any such resignation, the Required Lenders shall have the right (subject to the prior written approval of the Borrowers, which approval may not be unreasonably withheld, conditioned or delayed and shall not be required while an Event of Default has occurred and is continuing) to appoint one of the Lenders to be successor Administrative Agent. If no successor Administrative Agent shall have been so appointed by the Required Lenders, and shall have accepted such appointment, within thirty (30) days after the retiring Administrative Agent’s giving of notice of resignation, then the retiring Administrative Agent may, on behalf of the Lenders, appoint one of the Lenders to be successor Administrative Agent. In either case, such appointment shall be subject to the prior written approval of the Borrowers (which approval may not be unreasonably withheld and shall not be required while an Event of Default has occurred and is continuing). Upon the acceptance of any appointment as Administrative Agent by a successor Administrative Agent, such successor Administrative Agent shall succeed to, and become vested with, all the rights, powers, privileges and duties of the retiring Administrative Agent. Upon the acceptance of appointment as Administrative Agent by a successor Administrative Agent, the retiring Administrative Agent shall be discharged from its duties and obligations under this Agreement and the other Loan Documents. Prior to any retiring Administrative Agent’s resignation hereunder as Administrative Agent, the retiring Administrative Agent shall take such action as may be reasonably necessary to assign to the successor Administrative Agent its rights as Administrative Agent under the Loan Documents.

(b) Notwithstanding paragraph (a) of this Section, in the event no successor Administrative Agent shall have been so appointed and shall have accepted such appointment within thirty (30) days after the retiring Administrative Agent gives notice of its intent to resign, the retiring Administrative Agent may give notice of the effectiveness of its resignation to the Lenders and the Borrowers, whereupon, on the date of effectiveness of such resignation stated in such notice, (i) the retiring Administrative Agent shall be discharged from its duties and obligations as the Administrative Agent hereunder and under the other Loan Documents; provided that, solely for purposes of maintaining any security interest granted to the Administrative Agent for the benefit of the Lenders, the retiring Administrative Agent shall continue to be vested with such security interest as collateral agent for the benefit of the Lenders, and continue to be entitled to the rights set forth in any related security documents, and, in the case of any collateral in the possession of the Administrative Agent, shall continue to hold such collateral, in each case until such time as a successor Administrative Agent is appointed and accepts such appointment in accordance with this Section (it being understood and agreed that

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the retiring Administrative Agent shall have no duty or obligation to take any further action under any security document, including any action required to maintain the perfection of any such security interest), and (ii) the Required Lenders shall succeed to and become vested with all the rights, powers, privileges and duties of the retiring Administrative Agent; provided that (A) all payments required to be made hereunder or under any other Loan Document to the Administrative Agent for the account of any Person other than the Administrative Agent shall be made directly to such Person and (B) all notices and other communications required or contemplated to be given or made to the Administrative Agent shall directly be given or made to each Lender. Following the effectiveness of the Administrative Agent’s resignation from its capacity as such, the provisions of this Section 8 and Section 9.5, as well as any exculpatory, reimbursement and indemnification provisions set forth in any other Loan Document, shall continue in effect for the benefit of such retiring Administrative Agent, its sub-agents and their respective Related Parties in respect of any actions taken or omitted to be taken by any of them while the retiring Administrative Agent was acting as Administrative Agent and in respect of the matters referred to in the proviso under clause (i) above.

8.6 Acknowledgements of Lenders.

(a) Each Lender represents and warrants that (i) the Loan Documents set forth the terms of a commercial lending facility, (ii) it is engaged in making, acquiring or holding commercial loans in the ordinary course of business, and is making the Loans hereunder as commercial loans in the ordinary course of its business and not for the purpose of purchasing, acquiring or holding any other type of financial instrument (and each Lender agrees not to assert a claim in contravention of the foregoing), (iii) it has, independently and without reliance upon the Administrative Agent or any other Lender, or any of the Related Parties of any of the foregoing, and based on such documents and information as it has deemed appropriate, made its own credit analysis and decision to enter into this Agreement as a Lender, and to make, acquire or hold Loans hereunder and (iv) it is sophisticated with respect to decisions to make, acquire and/or hold commercial loans and either it, or the Person exercising discretion in making its decision to make, acquire and/or hold such commercial loans is experienced in making, acquiring or holding such commercial loans. Each Lender also acknowledges that it will, independently and without reliance upon the Administrative Agent or any other Lender, or any of the Related Parties of any of the foregoing, and based on such documents and information (which may contain material, non-public information within the meaning of the United States securities laws concerning the Borrowers and their Affiliates) as it shall from time to time deem appropriate, continue to make its own decisions in taking or not taking action under or based upon this Agreement, any other Loan Document or any related agreement or any document furnished hereunder or thereunder.

(b) Each Lender, by delivering its signature page to this Agreement on the Effective Date, or delivering its signature page to an Assignment and Acceptance or any other Loan Document pursuant to which it shall become a Lender hereunder, shall be deemed to have acknowledged receipt of, and consented to and approved, each Loan Document and each other document required to be delivered to, or be approved by or satisfactory to, the Administrative Agent or the Lenders on the Effective Date.

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(c) (i) Each Lender hereby agrees that (x) if the Administrative Agent notifies such Lender that the Administrative Agent has determined in its sole discretion that any funds received by such Lender from the Administrative Agent or any of its Affiliates (whether as a payment, prepayment or repayment of principal, interest, fees or otherwise; individually and collectively, a “Payment”) were erroneously transmitted to such Lender (whether or not known to such Lender), and demands the return of such Payment (or a portion thereof), such Lender shall promptly, but in no event later than one Business Day thereafter, return to the Administrative Agent the amount of any such Payment (or portion thereof) as to which such a demand was made in same day funds, together with interest thereon in respect of each day from and including the date such Payment (or portion thereof) was received by such Lender to the date such amount is repaid to the Administrative Agent at the greater of the Federal Funds Rate and a rate determined by the Administrative Agent in accordance with banking industry rules on interbank compensation from time to time in effect, and (y) to the extent permitted by applicable law, such Lender shall not assert, and hereby waives, as to the Administrative Agent, any claim, counterclaim, defense or right of set-off or recoupment with respect to any demand, claim or counterclaim by the Administrative Agent for the return of any Payments received, including without limitation any defense based on “discharge for value” or any similar doctrine. A notice of the Administrative Agent to any Lender under this Section 8.6(c) shall be conclusive, absent manifest error.

(ii) Each Lender hereby further agrees that if it receives a Payment from the Administrative Agent or any of its Affiliates (x) that is in a different amount than, or on a different date from, that specified in a notice of payment sent by the Administrative Agent (or any of its Affiliates) with respect to such Payment (a “Payment Notice”) or (y) that was not preceded or accompanied by a Payment Notice, it shall be on notice, in each such case, that an error has been made with respect to such Payment. Each Lender agrees that, in each such case, or if it otherwise becomes aware a Payment (or portion thereof) may have been sent in error, such Lender shall promptly notify the Administrative Agent of such occurrence and, upon demand from the Administrative Agent, it shall promptly, but in no event later than one Business Day thereafter, return to the Administrative Agent the amount of any such Payment (or portion thereof) as to which such a demand was made in same day funds, together with interest thereon in respect of each day from and including the date such Payment (or portion thereof) was received by such Lender to the date such amount is repaid to the Administrative Agent at the greater of the Federal Funds Rate and a rate determined by the Administrative Agent in accordance with banking industry rules on interbank compensation from time to time in effect.

(iii) Each Borrower hereby agrees that (x) in the event an erroneous Payment (or portion thereof) are not recovered from any Lender that has received such Payment (or portion thereof) for any reason, the Administrative Agent shall be subrogated to all the rights of such Lender with respect to such amount and (y) an erroneous Payment shall not pay, prepay, repay, discharge or otherwise satisfy any Obligations owed by such Borrower, except, in each case, to the extent such erroneous Payment is, and solely with respect to the amount of such erroneous Payment that is, comprised of funds received by the Administrative Agent or any of its Affiliates from such Borrower for the purpose of making such erroneous Payment.

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(iv) Each party’s obligations under this Section 8.6(c) shall survive the resignation or replacement of the Administrative Agent or any transfer of rights or obligations by, or the replacement of, a Lender, the termination of the Commitments or the repayment, satisfaction or discharge of all obligations under any Loan Document.

(d) Each Lender hereby represents and warrants that it is a Bank (as defined in the 1940 Act). Each Lender will promptly notify the Borrowers and the Administrative Agent if it is no longer a Bank (as defined in the 1940 Act).

8.7 Duties of Syndication Agents. No Syndication Agent, in its capacity as such, shall have any duty, obligation or responsibility hereunder.

SECTION 9. MISCELLANEOUS

9.1 Amendments and Waivers. Neither this Agreement nor any other Loan Document, nor any terms hereof or thereof, may be amended, supplemented or modified except in accordance with the provisions of this Section. The Required Lenders may, or, with the written consent of the Required Lenders, the Administrative Agent may, from time to time, (a) enter into with each Registrant, on behalf of the series thereof which are Borrowers, written amendments, supplements or modifications hereto and to the other Loan Documents for the purpose of adding any provisions to this Agreement or the other Loan Documents or changing in any manner the rights of the Lenders or of such Borrowers hereunder or thereunder or (b) waive, on such terms and conditions as the Required Lenders or the Administrative Agent, as the case may be, may specify in such instrument, any of the requirements of this Agreement or the other Loan Documents or any Default or Event of Default and its consequences; provided, however, that no such waiver and no such amendment, supplement or modification shall (i) reduce the amount or extend the scheduled date of maturity of any Loan or of any installment thereof, or reduce the stated rate of any interest or fee payable hereunder or extend the scheduled date of any payment thereof or increase the amount or extend the expiration date of any Lender’s Commitment, in each case without the consent of each Lender affected thereby, or (ii) amend, modify or waive any provision of this Section 9.1 (or any other provision of this Agreement which expressly provides that the consent of all the Lenders is required to take any action) or reduce the percentage specified in the definition of Required Lenders, or consent to the assignment or transfer by any Borrower or any Registrant of any of its rights and obligations under this Agreement and the other Loan Documents, in each case without the written consent of all the Lenders or (iii) amend, waive or modify the first three sentences of Section 2.9(a) or any other provision affecting the ratable treatment of the Lenders, in each case without the written consent of all the Lenders, or (iv) amend, waive or modify the requirement contained in the first sentence of Section 2.16(a) that consent of all the Lenders is required to approve the addition of Borrowers to this Agreement, in each case without the written consent of all the Lenders, or (v) amend, waive or modify Section 2.6(b) without the written consent of all the Lenders (other than any Defaulting Lenders), or (vi) amend, waive or modify Section 6.1 without the written consent of all the Lenders (other than any Defaulting Lenders), (vii) amend, modify or waive any provision of Section 8 without the written consent of the then Administrative Agent, or (viii) amend, waive or modify Section 4 without the written consent of all the Lenders (other than any Defaulting Lenders), or (ix) amend, waive or modify Section 2.10 without the written consent of all the Lenders (other than any Defaulting Lenders) or (x) amend, waive or modify Section 9.7(a)

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without the written consent of all the Lenders (other than any Defaulting Lenders). Any such waiver and any such amendment, supplement or modification shall be effective (A) only for such Borrower(s) on whose behalf a Registrant executed such document(s) and (B) in the specific instance and for the specific purpose for which given.

9.2 Notices. All notices, requests and demands to or upon the respective parties hereto to be effective shall be in writing (which writing may be in the form of a facsimile transmission), and, unless otherwise expressly provided herein, shall be deemed to have been duly given or made when delivered, or five days after being deposited in the mail, postage prepaid, or, in the case of facsimile notice, when received, addressed as follows in the case of any Registrant, any Borrower and the Administrative Agent, and as set forth in Schedule II in the case of the other parties hereto, or to such other address as may be hereafter notified by the respective parties hereto:

The Borrowers	COLUMBIA MANAGEMENT INVESTMENT
and Registrants:	ADVISERS, LLC
	225 Franklin Street
	Boston, MA 02110
	Attention: Mr. Michael G. Clarke
	COLUMBIA WANGER ASSET MANAGEMENT, LLC
	227 West Monroe, Suite 3000
	Chicago, IL 60606, USA
	Attention: Mr. Michael G. Clarke
with a copy to:	COLUMBIA FUNDS
	5228 Ameriprise Financial Center
	Minneapolis, MN 55474
	Attention: GCO – Asset Management Legal
The Administrative Agent:	JPMORGAN CHASE BANK, N.A.
	500 Stanton Christiana Road, NCC5
	Newark, DE 19713
	Attention: Andrew Weyant
	Phone: (302) 552-0714
	Fax: (302) 634 8459 / 12012443577@tls.ldsprod.com
	Email: andrew.weyant@chase.com
With a copy to:	Pryor Cashman LLP
	7 Times Square
	New York, NY 10036
	Attn: Larry Remmel, Esq.
	Facsimile: (212) 326-0806

provided that any notice, request or demand to or upon the Administrative Agent or the Lenders pursuant to Section 2.2, 2.4, 2.6, or 2.8 shall not be effective until received.

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9.3 No Waiver; Cumulative Remedies. No failure to exercise and no delay in exercising, on the part of any party hereto, any right, remedy, power or privilege hereunder or under the other Loan Documents shall operate as a waiver thereof; nor shall any single or partial exercise of any right, remedy, power or privilege hereunder preclude any other or further exercise thereof or the exercise of any other right, remedy, power or privilege. The rights, remedies, powers and privileges herein provided are cumulative and not exclusive of any rights, remedies, powers and privileges provided by law.

9.4 Survival of Representations and Warranties. All representations and warranties made hereunder, in the other Loan Documents and in any document, certificate or statement delivered pursuant hereto or in connection herewith shall survive the execution and delivery of this Agreement and the making of the Loans hereunder.

9.5 Payment of Expenses and Taxes; Indemnification; Etc.

(a) Expenses. Each Borrower agrees severally (ratably, in accordance with its respective Pro Rata Allocation) to pay (i) all reasonable out of pocket expenses incurred by the Administrative Agent and J.P. Morgan Securities LLC, including the reasonable fees, charges and disbursements of counsel for the Administrative Agent, in connection with the syndication of the credit facilities provided for herein, the preparation and administration of this Agreement and the other Loan Documents or any amendments, modifications or waivers of the provisions hereof or thereof (whether or not the transactions contemplated hereby or thereby shall be consummated), and (ii) all reasonable and documented out-of-pocket expenses incurred by the Administrative Agent or any Lender, including the reasonable and documented fees, charges and disbursements of any counsel for the Administrative Agent or any Lender, in connection with the enforcement or protection of its rights in connection with this Agreement and the other Loan Documents, including its rights under this Section, or in connection with the Loans made hereunder, including all such reasonable and documented out-of-pocket expenses incurred during any workout, restructuring or negotiations in respect of such Loans.

(b) Limitation of Liability. To the extent permitted by applicable law (i) no Registrant or Borrower (each a “Loan Party”) shall assert, and each Loan Party hereby waives, any claim against the Administrative Agent and any Lender, and any Related Party of any of the foregoing Persons (each such Person a “Lender-Related Person”) for any Liabilities arising from the use by others of information or other materials (including, without limitation, any personal data) obtained through telecommunications, electronic or other information transmission systems (including the Internet); provided that such waiver shall not apply to the extent such claim arises from, with respect to any Lender-Related Person, the gross negligence or willful misconduct of such Lender-Related Person as determined by a court of competent jurisdiction by final and non-appealable judgment, and (ii) no party hereto shall assert, and each such party hereby waives, any Liabilities against any other party hereto, on any theory of liability, for special, indirect, consequential or punitive damages (as opposed to direct or actual damages) arising out of, in connection with, or as a result of, this Agreement, any other Loan Document, or any agreement or instrument contemplated hereby or thereby, the Transactions, any Loan or the use of the proceeds thereof; provided that, nothing in this Section 9.5(b) shall relieve any Loan Party of any obligation it may have to indemnify an Indemnitee, as provided in Section 9.5(c), against any special, indirect, consequential or punitive damages asserted against such Indemnitee by a third party.

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(c) Indemnity. Each Borrower agrees severally (ratably, in accordance with its respective Pro Rata Allocation) to indemnify the Administrative Agent and each Lender, and each Related Party of any of the foregoing Persons (each such Person being called an “Indemnitee”) against, and hold each Indemnitee harmless from, any and all Liabilities and related expenses, including the fees, charges and disbursements of any counsel for any Indemnitee, incurred by or asserted against any Indemnitee arising out of, in connection with, or as a result of (i) the execution or delivery of this Agreement, any other Loan Document, or any agreement or instrument contemplated hereby or thereby, the performance by the parties hereto of their respective obligations hereunder or thereunder or the consummation of the Transactions or any other transactions contemplated hereby, (ii) any Loan or the use of the proceeds therefrom, or (iii) any actual or prospective Proceeding relating to any of the foregoing, whether or not such Proceeding is brought by any Borrower or any other Loan Party or its or their respective equity holders, Affiliates, creditors or any other third Person and whether based on contract, tort or any other theory and regardless of whether any Indemnitee is a party thereto; provided that such indemnity shall not, as to any Indemnitee, be available to the extent that such Liabilities or related expenses are determined by a court of competent jurisdiction by final and nonappealable judgment to have resulted primarily from the gross negligence or willful misconduct of such Indemnitee. This Section 9.5(c) shall not apply with respect to Taxes other than any Taxes that represent losses, claims or damages arising from any non-Tax claim.

(d) Lender Reimbursement. Each Lender severally agrees to pay any amount required to be paid by any Borrower under paragraphs (a), (b) or (c) of this Section 9.5 to the Administrative Agent and each Related Party of any of the foregoing Persons (each, an “Agent-Related Person”) (to the extent not reimbursed by such Borrower and without limiting the obligation of the Borrowers to do so), ratably according to their respective Commitment Percentage in effect on the date on which such payment is sought under this Section (or, if such payment is sought after the date upon which the Commitments shall have terminated and the Loans shall have been paid in full, ratably in accordance with such Commitment Percentage immediately prior to such date), from and against any and all Liabilities and related expenses, including the fees, charges and disbursements of any kind whatsoever that may at any time (whether before or after the payment of the Loans) be imposed on, incurred by or asserted against such Agent-Related Person in any way relating to or arising out of the Commitments, this Agreement, any of the other Loan Documents or any documents contemplated by or referred to herein or therein or the transactions contemplated hereby or thereby or any action taken or omitted by such Agent-Related Person under or in connection with any of the foregoing; provided that the unreimbursed expense or Liability or related expense, as the case may be, was incurred by or asserted against such Agent-Related Person in its capacity as such; provided further that no Lender shall be liable for the payment of any portion of such Liabilities, costs, expenses or disbursements that are found by a final and nonappealable decision of a court of competent jurisdiction to have resulted primarily from such Agent-Related Party’s gross negligence or willful misconduct. The agreements in this Section shall survive the termination of this Agreement and the payment of the Loans and all other amounts payable hereunder.

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(e) Payments. All amounts due under this Section 9.5(d) shall be payable not later than 10 days after written demand therefor (which demand shall include a statement describing in reasonable detail the basis for making such demand).

(f) Allocation of Liability. Notwithstanding any other provision in this Agreement to the contrary, to the extent any obligation to reimburse or indemnify any Indemnitee that arises pursuant to Section 9.5(b) is not attributable to any particular Borrower or Borrowers, then such reimbursement or indemnification shall be made by each Borrower (ratably, in accordance with its respective Pro Rata Allocation). To the extent any such obligation to reimburse or indemnify any Indemnified Party is attributable to one or more Borrowers, then such reimbursement or indemnification shall be made by such Borrower or, if more than one Borrower, ratably by such Borrowers based on their respective Pro Rata Allocations.

9.6 Successors and Assigns; Participations and Assignments. (a) This Agreement shall be binding upon and inure to the benefit of the Registrants, the Borrowers, the Lenders, the Administrative Agent and their respective successors and assigns, except that, except as may otherwise be provided herein, neither any Registrant nor any Borrower may assign or transfer any of its rights or obligations under this Agreement without the prior written consent of each Lender.

(b) Any Lender may, in the ordinary course of its commercial banking business and in accordance with Applicable Laws, at any time sell to one or more Eligible Lenders (“Participants”) participating interests in any Loan owing to such Lender, any Commitment of such Lender or any other interest of such Lender hereunder and under the other Loan Documents. In the event of any such sale by a Lender of a participating interest to a Participant, such Lender’s obligations under this Agreement to the other parties to this Agreement shall remain unchanged, such Lender shall remain solely responsible for the performance thereof, such Lender shall remain the holder of any such Loan for all purposes under this Agreement and the other Loan Documents, and the Borrowers and the Administrative Agent shall continue to deal solely and directly with such Lender in connection with such Lender’s rights and obligations under this Agreement and the other Loan Documents. Any agreement pursuant to which any Lender may grant such a participating interest shall provide that such Lender shall retain the sole right and responsibility to enforce the obligations of the Borrowers hereunder, including the right to approve any amendment, modification or waiver of any provision of this Agreement; provided that such participation agreement may provide that (i) such Lender will not agree to any modification, amendment or waiver of this Agreement described in clauses (i) through (ix) of the proviso in Section 9.1 without the consent of the Participant and (ii) the Participant may obtain voting rights limited to changes in respect of the principal amount, interest rates, fees and term of the Loans. Each Lender that sells a participation shall, acting solely for this purpose as a non-fiduciary agent of the Borrowers, maintain a register on which it enters the name and address of each Participant and the principal amounts (and stated interest) of each Participant’s interest in the Notes or other obligations under the Agreement (the “Participant Register”); provided that no Lender shall have any obligation to disclose all or any portion of the Participant Register (including the identity of any Participant or any information relating to a Participant’s interest in any Commitments, Loans or its other obligations under any Loan Document) to any Person except to the extent that such disclosure is necessary to establish that such Commitment, Loan or other obligation is in registered form under

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Section 5f.103-1(c) of the United States Treasury Regulations. The entries in the Participant Register shall be conclusive absent manifest error, and each Person whose name is recorded in the Participant Register shall be treated as the owner of such participation for all purposes of this Agreement notwithstanding any notice to the contrary. For the avoidance of doubt, the Administrative Agent (in its capacity as Administrative Agent) shall have no responsibility for maintaining a Participant Register.

(c) Any Lender may, in the ordinary course of its commercial banking business and in accordance with Applicable Law, at any time and from time to time assign to any Lender or any Affiliate thereof that is an Eligible Lender or, with the consent of the Administrative Agent (not to be unreasonably withheld or delayed) and (so long as no Default or Event of Default shall have occurred and be continuing) the Registrants (not to be unreasonably withheld or delayed, and provided that the Registrants shall be deemed to have consented to any such assignment unless they shall object thereto by written notice to the Administrative Agent within three (3) Business Days), to an additional Eligible Lender (an “Assignee”) all or any part of its rights and obligations under this Agreement and the other Loan Documents pursuant to an Assignment and Acceptance, substantially in the form of Exhibit 9.6(c), executed by such Assignee, such assigning Lender and the Administrative Agent (and, provided (i) no Default or Event of Default shall have occurred and be continuing and (ii) the Assignee is not a Lender or an Affiliate of a Lender that is an Eligible Lender, the Registrants) and delivered to the Administrative Agent for its acceptance and recording in the Register; provided, however, that assignments to entities other than Lenders or Affiliates thereof must be in amounts of at least $5,000,000 (or, in the case of an Assignment and Acceptance covering all or the remaining portion of an assigning Lender’s rights and obligations under this Agreement, all of such lesser amount). Upon such execution, delivery, acceptance and recording, from and after the effective date determined pursuant to such Assignment and Acceptance, (x) the Assignee thereunder shall be a party hereto and, to the extent provided in such Assignment and Acceptance, have the rights and obligations of a Lender hereunder with a Commitment as set forth therein, and (y) the assigning Lender thereunder shall, to the extent provided in such Assignment and Acceptance, be released from its obligations under this Agreement (and, in the case of an Assignment and Acceptance covering all or the remaining portion of an assigning Lender’s rights and obligations under this Agreement, such assigning Lender shall cease to be a party hereto (except as to Sections 2.10, 2.11 and 9.5 in respect of the period prior to the effective date of such Assignment and Acceptance) and the Commitment of the Assignee shall be in an amount equal to that of such assigning Lender prior to the execution of such Assignment and Acceptance).

(d) The Administrative Agent, on behalf of the Borrowers, shall maintain at the address of the Administrative Agent referred to in Section 9.2 a copy of each Assignment and Acceptance delivered to it and a register (the “Register”) for the recordation of the names and addresses of the Lenders and the Commitment of, and principal amount of the Loans owing to, each Lender from time to time. The entries in the Register shall be conclusive, in the absence of manifest error, and each Borrower, the Administrative Agent and the Lenders may (and, in the case of any Loan or other obligation hereunder not evidenced by a Note, shall) treat each Person whose name is

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recorded in the Register as the owner of a Loan or other obligation hereunder as the owner thereof for all purposes of this Agreement and the other Loan Documents, notwithstanding any notice to the contrary. Any assignment of any Loan or other obligation hereunder not evidenced by a Note shall be effective only upon appropriate entries with respect thereto being made in the Register. The Register shall be available for inspection by the Borrowers or any Lender at any reasonable time and from time to time upon reasonable prior notice.

(e) Upon its receipt of an Assignment and Acceptance executed by an assigning Lender and an Assignee (and the Administrative Agent) together with payment by the assigning Lender or Assignee to the Administrative Agent of a registration and processing fee of $3,000 (for which no Borrower shall have an obligation to reimburse), the Administrative Agent shall (i) promptly accept such Assignment and Acceptance and (ii) on the effective date determined pursuant thereto record the information contained therein in the Register and give notice of such acceptance and recordation to the Lenders and to each Borrower.

(f) Each Borrower authorizes each Lender to disclose to any Participant or Assignee (each, a “Transferee”) and any prospective Transferee any and all financial information in such Lender’s possession concerning such Borrower and its Affiliates which has been delivered to such Lender by or on behalf of such Borrower pursuant to this Agreement or which has been delivered to such Lender by or on behalf of such Borrower in connection with such Lender’s credit evaluation of the Registrants, the Borrowers and their Affiliates prior to becoming a party to this Agreement subject to the obligations in Section 9.10(b).

(g) For avoidance of doubt, the parties to this Agreement acknowledge that the provisions of this Section concerning assignments of Loans and Notes relate only to absolute assignments and that such provisions do not prohibit assignments creating security interests, including, without limitation, any pledge or assignment by a Lender of any Loan or Note to any Federal Reserve Bank, or any other central bank having jurisdiction over such Lender, in accordance with Applicable Law.

9.7 Adjustments; Set-off. (a) Subject to Section 2.2(b), if any Lender (a “Benefited Lender”) shall at any time receive any payment of all or part of its Loans, or interest thereon, or receive any collateral in respect thereof (whether voluntarily or involuntarily, by set-off, pursuant to events or proceedings of the nature referred to in Section 7(e), or otherwise), in a greater proportion than any such payment to or collateral received by any other Lender, if any, in respect of such other Lender’s Loans, or interest thereon, such Benefited Lender shall purchase for cash from the other Lenders a participating interest in such portion of each such other Lender’s Loans, or shall provide such other Lenders with the benefits of any such collateral, or the proceeds thereof, as shall be necessary to cause such Benefited Lender to share the excess payment or benefits of such collateral or proceeds ratably with each of the Lenders; provided, however, that if all or any portion of such excess payment or benefits is thereafter recovered from such Benefited Lender, such purchase shall be rescinded, and the purchase price and benefits returned, to the extent of such recovery, but without interest; provided further that the provisions of this paragraph shall not be construed to apply to any payment obtained by a Lender as consideration for the assignment of or sale of a participation in any of its Loans to any assignee or participant.

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(b) In addition to any rights and remedies of the Lenders provided by law, upon the occurrence of an Event of Default each Lender is hereby authorized at any time or from time to time, without presentment, demand, protest or other notice of any kind to the defaulting Borrower, Registrant, Columbia Management or any other Person, any such notice being hereby expressly waived, to the extent permitted by Applicable Law, upon any amount becoming due and payable by a Borrower hereunder (whether at the stated maturity, by acceleration or otherwise) to set off and appropriate and apply against such amount any and all deposits (general or special, time or demand, provisional or final), in any currency, and any other credits, indebtedness or claims, in any currency, in each case whether direct or indirect, absolute or contingent, matured or unmatured, at any time held or owing by such Lender or any branch or agency thereof to or for the credit or the account of such Borrower. Each Lender agrees promptly to notify such Borrower and the Administrative Agent after any such set-off and application made by such Lender, provided that the failure to give such notice shall not affect the validity of such set-off and application.

9.8 Counterparts; effectiveness; Electronic Execution. (a) This Agreement may be executed by one or more of the parties to this Agreement on any number of separate counterparts (including by facsimile transmission), and all of said counterparts taken together shall be deemed to constitute one and the same instrument. A set of the copies of this Agreement signed by all the parties shall be lodged with Columbia Management and the Administrative Agent.

(b) Delivery of an executed counterpart of a signature page of (x) this Agreement, (y) any other Loan Document and/or (z) any document, amendment, approval, consent, information, notice (including, for the avoidance of doubt, any notice delivered pursuant to Section 9.2), certificate, request, statement, disclosure or authorization related to this Agreement, any other Loan Document and/or the transactions contemplated hereby and/or thereby (each an “Ancillary Document”) that is an Electronic Signature transmitted by telecopy, emailed pdf. or any other electronic means that reproduces an image of an actual executed signature page shall be effective as delivery of a manually executed counterpart of this Agreement, such other Loan Document or such Ancillary Document, as applicable. The words “execution,” “signed,” “signature,” “delivery,” and words of like import in or relating to this Agreement, any other Loan Document and/or any Ancillary Document shall be deemed to include Electronic Signatures, deliveries or the keeping of records in any electronic form (including deliveries by telecopy, emailed pdf. or any other electronic means that reproduces an image of an actual executed signature page), each of which shall be of the same legal effect, validity or enforceability as a manually executed signature, physical delivery thereof or the use of a paper-based recordkeeping system, as the case may be; provided that nothing herein shall require the Administrative Agent to accept Electronic Signatures in any form or format without its prior written consent and pursuant to procedures approved by it; provided, further, without limiting the foregoing, (i) to the extent the Administrative Agent has agreed to accept any Electronic Signature, the Administrative Agent and each of the Lenders shall be entitled to rely on such Electronic Signature purportedly given by or on behalf of each Borrower without further

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verification thereof and without any obligation to review the appearance or form of any such Electronic signature and (ii) upon the request of the Administrative Agent or any Lender, any Electronic Signature shall be promptly followed by a manually executed counterpart. Without limiting the generality of the foregoing, each Borrower hereby (i) agrees that, for all purposes, including without limitation, in connection with any workout, restructuring, enforcement of remedies, bankruptcy proceedings or litigation among the Administrative Agent, the Lenders, and any Borrower, Electronic Signatures transmitted by telecopy, emailed pdf. or any other electronic means that reproduces an image of an actual executed signature page and/or any electronic images of this Agreement, any other Loan Document and/or any Ancillary Document shall have the same legal effect, validity and enforceability as any paper original, (ii) agrees that the Administrative Agent and each of the Lenders may, at its option, create one or more copies of this Agreement, any other Loan Document and/or any Ancillary Document in the form of an imaged electronic record in any format, which shall be deemed created in the ordinary course of such Person’s business, and destroy the original paper document (and all such electronic records shall be considered an original for all purposes and shall have the same legal effect, validity and enforceability as a paper record), (iii) waives any argument, defense or right to contest the legal effect, validity or enforceability of this Agreement, any other Loan Document and/or any Ancillary Document based solely on the lack of paper original copies of this Agreement, such other Loan Document and/or such Ancillary Document, respectively, including with respect to any signature pages thereto and (iv) waives any claim against any Lender-Related Person for any Liabilities arising solely from the Administrative Agent’s and/or any Lender’s reliance on or use of Electronic Signatures and/or transmissions by telecopy, emailed pdf. or any other electronic means that reproduces an image of an actual executed signature page, including any Liabilities arising as a result of the failure of such Borrower to use any available security measures in connection with the execution, delivery or transmission of any Electronic Signature.

9.9 Severability. Any provision of this Agreement which is prohibited or unenforceable in any jurisdiction shall, as to such jurisdiction, be ineffective to the extent of such prohibition or unenforceability without invalidating the remaining provisions hereof, and any such prohibition or unenforceability in any jurisdiction shall not invalidate or render unenforceable such provision in any other jurisdiction.

9.10 Waiver of Conflicts; Confidentiality. (a) Each Borrower acknowledges that each of the Administrative Agent and each Lender and their respective affiliates (collectively, the “Bank Parties”) may be providing debt financing, equity capital or other services (including financial advisory services) to other companies in respect of which such Borrowers may have conflicting interests regarding the transactions described herein and otherwise. Except as may otherwise be permitted herein, the Bank Parties will not disclose Confidential Information obtained from such Borrowers and their related Registrants by virtue of the transactions contemplated by this Agreement or their other relationships with such Borrowers and their related Registrants in connection with the performance by each of the Bank Parties of services for other companies, and each of the Bank Parties will not disclose any such Confidential Information to such other companies. Such Borrowers also acknowledge that no Bank Party has any obligation to use in connection with the transactions contemplated by this Agreement, or to furnish to any Borrower, confidential information obtained from other companies.

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(b) For purposes of this Section, “Confidential Information” shall mean all information received from any of the Registrants, the Borrowers or Columbia Management relating to any of them or their business, other than any such information that is available to the Administrative Agent or any Lender on a nonconfidential basis other than as a result of a breach of this Agreement. Each of the Administrative Agent and each Lender agrees to maintain the confidentiality of the Confidential Information, and shall use such Confidential Information only for the purpose of determining the creditworthiness of a Borrower, in connection with the enforcement of the rights of each Lender under this Agreement and in the administration of the credit facility contemplated by this Agreement, except that Confidential Information may be disclosed (i) to its and its Affiliates’ directors, officers, employees and agents, including without limitation accountants, legal counsel and other advisors for purposes relating to the transactions contemplated by this Agreement or for conducting legitimate audits (it being understood that the Persons to whom such disclosure is made will be informed of the confidential nature of such Confidential Information and will be subject to the provisions of this Section 9.10 to the same extent as any Lender), (ii) to the extent requested by any legal or regulatory or self-regulatory authority having or claiming jurisdiction over such Person, (iii) to the extent required by Applicable Laws or regulations or by any subpoena or similar legal process, (iv) to any other party to this Agreement for purposes relating to the transactions contemplated hereby, (v) in connection with the exercise of any remedies hereunder or any suit, action or proceeding relating to this Agreement or the enforcement of rights hereunder, (vi) subject to an agreement containing provisions substantially the same as those of this subsection, to any Assignee or Participant or any prospective Assignee or Participant which executes such agreement, or to any actual or prospective party (and its advisor and agents) to any swap, derivative, securitization, credit insurance or other transaction under which payments are to be made by reference to a Borrower and its obligations, the Credit Agreement or payment hereunder, or (vii) with the written consent of the Borrowers. Any Person required to maintain the confidentiality of Confidential Information as provided in this Section shall be considered to have complied with its obligation to do so if such Person has exercised the same degree of care to maintain the confidentiality of such Information as such Person would accord to its own confidential information.

(c) Without limiting the foregoing provisions of this Section, in the event that (I) any party to this Agreement (the “Providing Party”) provides to another party to this Agreement (the “Recipient Party”) non-public personal information concerning individual investors in any Fund that such Providing Party is required to keep confidential under applicable provisions of the Customer Confidentiality Laws and (II) such Providing Party properly identifies such information as such to the Recipient Party at the time such information is provided by, among other means of identification, prominently marking such information with the words “NON-PUBLIC INFORMATION SUBJECT TO CUSTOMER CONFIDENTIALITY LAWS AND SECTIONS 9.10(b) and (c) OF THE AMENDED AND RESTATED CREDIT AGREEMENT”, the Recipient Party shall treat such information as required by the applicable provisions of the Customer Confidentiality Laws, it being understood that this sentence does not, and is not intended to, create independent rights, or rights of action or obligations, for any Person not a party to this Agreement and any such action shall constitute an “indemnified

71

liability” under Section 9.5. “Customer Confidentiality Laws” means Title V of Public Law 106-102, known as the “Graham-Leach-Bliley Act”, 15 USC 6801 to 6809, and the rules and regulations adopted thereunder. Nothing in this Section shall require any Borrower, any Registrant or Columbia Management to provide any such non-public personal information concerning individual investors in any Fund to any Person.

9.11 GOVERNING LAW. THIS AGREEMENT AND THE RIGHTS AND OBLIGATIONS OF THE PARTIES HEREUNDER SHALL BE GOVERNED BY, AND CONSTRUED AND INTERPRETED IN ACCORDANCE WITH, THE SUBSTANTIVE LAWS OF THE STATE OF NEW YORK, WITHOUT REGARD FOR ITS CHOICE OF LAW RULES.

9.12 Submission To Jurisdiction; Waivers. Each Registrant, on its own behalf and on behalf of the series thereof which are Borrowers, the Administrative Agent and the Lenders hereby irrevocably and unconditionally:

(a) submit for themselves and their respective property in any legal action or proceeding relating to this Agreement and the other Loan Documents to which they are a party, or for recognition and enforcement of any judgment in respect thereof, to the exclusive general jurisdiction of the Courts of the State of New York located in New York County (the borough of Manhattan), the courts of the United States of America for the Southern District of New York, and appellate courts from any thereof;

(b) consents that any such action or proceeding may be brought in such courts and waives any objection that it may now or hereafter have to the venue of any such action or proceeding in any such court or that such action or proceeding was brought in an inconvenient court and agrees not to plead or claim the same;

(c) agrees that service of process in any such action or proceeding may be effected by mailing a copy thereof by registered or certified mail (or any substantially similar form of mail), postage prepaid, to such Registrant or such Borrower at its address set forth in Section 9.2 or at such other address of which the Administrative Agent shall have been notified pursuant thereto;

(d) agrees that nothing herein shall affect the right of any party hereto to effect service of process in any other manner permitted by law or shall limit the right of any party hereto to sue in any other jurisdiction; and

(e) waives, to the maximum extent not prohibited by law, any right it may have to claim or recover in any legal action or proceeding referred to in this Section any special, exemplary, indirect, punitive or consequential damages.

9.13 Acknowledgments. Each Registrant, on its own behalf and on behalf of the series thereof which are Borrowers, hereby acknowledges that:

(a) it has been advised by general counsel in the negotiation, execution and delivery of this Agreement and the other Loan Documents;

72

(b) neither the Administrative Agent nor any Lender has any fiduciary relationship with or duty to such Registrant or any such Borrower arising out of or in connection with this Agreement or any of the other Loan Documents, and the relationship between the Administrative Agent and the Lenders, on the one hand, and such Registrant and each Borrower, on the other hand, in connection herewith or therewith is solely that of creditor and debtor; and

(c) no joint venture is created hereby or by the other Loan Documents or otherwise exists by virtue of the transactions contemplated hereby among the Lenders or among such Registrant, such Borrowers and the Lenders.

9.14 WAIVERS OF JURY TRIAL. EACH REGISTRANT, ON ITS OWN BEHALF AND ON BEHALF OF THE SERIES THEREOF WHICH ARE BORROWERS, THE ADMINISTRATIVE AGENT AND THE LENDERS HEREBY IRREVOCABLY AND UNCONDITIONALLY WAIVE TRIAL BY JURY IN ANY LEGAL ACTION OR PROCEEDING RELATING TO THIS AGREEMENT OR ANY OTHER LOAN DOCUMENT AND FOR ANY COUNTERCLAIM THEREIN.

9.15 Non-Recourse. The Administrative Agent and the Lenders hereby agree for the benefit of Columbia Management and its Affiliates, and each and every shareholder, trustee, director and officer of the Registrants and the Borrowers and any successor, assignee, heir, estate, executor, administrator or personal representative of any such shareholder, trustee, director and officer (a “Non-Recourse Person”) that: (a) no Non-Recourse Person shall have any personal liability for any obligation of any Registrant or Borrower under this Agreement or any other Loan Document or any other instrument or document delivered pursuant hereto or thereto (except, in the case of any shareholder, to the extent of his, her or its investment in a Borrower); (b) no claim against any Non-Recourse Person may be made for any obligation of any Registrant or any Borrower under this Agreement or any other Loan Document or any other instrument or document delivered pursuant hereto or thereto, whether for payment of principal of, or interest on, the Loans or for any fees, expense, or other amounts payable by any Registrant or any Borrower hereunder or thereunder, or otherwise; and (c) the obligations of each Borrower under this Agreement or any other Loan Document or any other instrument or document delivered pursuant hereto or thereto are enforceable solely against such Borrower and its properties and assets.

9.16 Integration. This Agreement and the other Loan Documents represent the entire agreement of each Registrant, on its own behalf and on behalf of the series thereof which are Borrowers, the Administrative Agent and the Lenders with respect to the subject matter hereof, and there are no promises, undertakings, representations or warranties by the Administrative Agent or any Lender relative to the subject matter hereof not expressly set forth or referred to herein or in the other Loan Documents.

9.17 USA PATRIOT Act. Each Lender hereby notifies the Borrowers that pursuant to the requirements of the USA Patriot Act (Title III of Pub. L. 107-56 (signed into law October 26, 2001)) (the “Act”), it is required to obtain, verify and record information that identifies the Borrowers, which information includes the name and address of the Borrowers and other information that will allow such Lender to identify the Borrowers in accordance with the Act. The Borrowers will provide such information promptly upon the request of such Lender.

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9.18 Net Asset Value. This Facility is not designed or intended to maintain a stable net asset value or share price of any Registrant or Borrower, and may not be relied upon or utilized by any Registrant or Borrower for such purpose.

9.19 Acknowledgement and Consent to Bail-In of Affected Financial Institutions. Notwithstanding anything to the contrary in any Loan Document or in any other agreement, arrangement or understanding among any such parties, each party hereto acknowledges that any liability of any Affected Financial Institution arising under any Loan Document may be subject to the write-down and conversion powers of the applicable Resolution Authority and agrees and consents to, and acknowledges and agrees to be bound by:

(a) the application of any Write-Down and Conversion Powers by the applicable Resolution Authority to any such liabilities arising hereunder which may be payable to it by any party hereto that is an Affected Financial Institution; and

(b) the effects of any Bail-In Action on any such liability, including, if applicable:

(i) a reduction in full or in part or cancellation of any such liability;

(ii) a conversion of all, or a portion of, such liability into shares or other instruments of ownership in such Affected Financial Institution, its parent entity, or a bridge institution that may be issued to it or otherwise conferred on it, and that such shares or other instruments of ownership will be accepted by it in lieu of any rights with respect to any such liability under this Agreement or any other Loan Document; or

(iii) the variation of the terms of such liability in connection with the exercise of the write-down and conversion powers of the applicable Resolution Authority.

9.20 Mauritius Subsidiaries. Notwithstanding anything to the contrary herein, each Mauritius Parent Borrower makes the additional representations and warranties, agrees to the additional covenants and is subject to the additional events of default, in each case, as set forth in Schedule 9.20 hereto.

9.21 No Fiduciary Duty, etc. (a) Each Borrower acknowledges and agrees, and acknowledges its Subsidiaries’ (if any) understanding, that no Credit Party will have any obligations except those obligations expressly set forth herein and in the other Loan Documents and each Credit Party is acting solely in the capacity of an arm’s length contractual counterparty to such Borrower with respect to the Loan Documents and the transactions contemplated herein and therein and not as a financial advisor or a fiduciary to, or an agent of, such Borrower or any other person. Each Borrower agrees that it will not assert any claim against any Credit Party based on an alleged breach of fiduciary duty by such Credit Party in connection with this Agreement and the transactions contemplated hereby. Additionally, each Borrower

74

acknowledges and agrees that no Credit Party is advising such Borrower as to any legal, tax, investment, accounting, regulatory or any other matters in any jurisdiction. Each Borrower shall consult with its own advisors concerning such matters and shall be responsible for making its own independent investigation and appraisal of the transactions contemplated herein or in the other Loan Documents, and the Credit Parties shall have no responsibility or liability to such Borrower with respect thereto.

(b) Each Borrower further acknowledges and agrees, and acknowledges its Subsidiaries’ understanding, that each Credit Party, together with its Affiliates, is a full service securities or banking firm engaged in securities trading and brokerage activities as well as providing investment banking and other financial services. In the ordinary course of business, any Credit Party may provide investment banking and other financial services to, and/or acquire, hold or sell, for its own accounts and the accounts of customers, equity, debt and other securities and financial instruments (including bank loans and other obligations) of, such Borrower and other companies with which such Borrower may have commercial or other relationships. With respect to any securities and/or financial instruments so held by any Credit Party or any of its customers, all rights in respect of such securities and financial instruments, including any voting rights, will be exercised by the holder of the rights, in its sole discretion.

[The remainder of this page intentionally left blank; signature pages follow.]

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IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be duly executed and delivered by their proper and duly authorized officers as of the day and year first written above.

JPMORGAN CHASE BANK, N.A., as Administrative Agent and as a Lender
By:	/s/ Kenise Henry Larmond
	Name: Kenise Henry Larmond
	Title: Vice President

COLUMBIA FUNDS 2021

AMENDED AND RESTATED CREDIT AGREEMENT

SIGNATURE PAGE

Accepted and agreed to as of

the date first above written:

Each of the Registrants listed on Schedule I for which Columbia Management Investment Advisers, LLC acts as investment manager and each of the Registrants listed on Schedule I for which Columbia Wanger Asset Management, LLC acts as investment manager, on behalf of itself and each of its underlying series set forth beneath its name on Schedule I

By:	/s/ Michael G. Clarke
	Name: Michael G. Clarke
	Title: *Chief Financial Officer, Principal Financial Officer and Senior Vice President / **
	Treasurer and Principal Accounting and Financial Officer

* (The above-signed officer holds this office with each of the Registrants fo r which Columbia Management Investment Advisers, LLC acts as investment manager)

** (The above-signed officer holds this office with each of the Registrants for which Columbia Wanger Asset Management, LLC acts as investment manager)

COLUMBIA FUNDS 2021

AMENDED AND RESTATED CREDIT AGREEMENT

SIGNATURE PAGE

CITIBANK, N .A.
By:	/s/ Maureen Maroney
	Name: Maureen Maroney
	Title: Vice President

COLUMBIA FUNDS 2021

AMENDED AND RESTATED CREDIT AGREEMENT

SIGNATURE PAGE

HSBC BANK USA, N.A.
By:	/s/ Nick White
	Name: Nick White
	Title: MD, Institutional Client Group

COLUMBIA FUNDS 2021

AMENDED AND RESTATED CREDIT AGREEMENT

SIGNATURE PAGE

WELLS FARGO BANK, N.A.
By:	/s/ Nik Broschofsky
	Name: Nik Broschofsky
	Title: Vice President

COLUMBIA FUNDS 2021

AMENDED AND RESTATED CREDIT AGREEMENT

SIGNATURE PAGE

U.S. BANK NATIONAL ASSOCIATION
By:	/s/ Christopher Balderston
	Name: Christopher Balderston
	Title: Assistant Vice President

COLUMBIA FUNDS 2021

AMENDED AND RESTATED CREDIT AGREEMENT

SIGNATURE PAGE

THE BANK OF NEW YORK MELLON
By:	/s/ Kenneth P. Sneider, Jr.
	Kenneth P. Sneider, Jr.
	Title: Director

COLUMBIA FUNDS 2021

AMENDED AND RESTATED CREDIT AGREEMENT

SIGNATURE PAGE

BANK OF AMERICA, N.A.
By:	/s/ Matthew C. White
	Name: Matthew C. White
	Title: Director

COLUMBIA FUNDS 2021

AMENDED AND RESTATED CREDIT AGREEMENT

SIGNATURE PAGE

BANK OF MONTREAL, CHICAGO BRANCH
By:	/s/ Amy Prager
	Name: Amy Prager
	Title: Director

COLUMBIA FUNDS 2021

AMENDED AND RESTATED CREDIT AGREEMENT

SIGNATURE PAGE

BNP PARIBAS NEW YORK BRANCH
By:	/s/ Monica Hanson
	Monica Hanson
	Managing Director
By:	/s/ Marguerite L. Lebon
	Marguerite L. Lebon
	Vice President

COLUMBIA FUNDS 2021

AMENDED AND RESTATED CREDIT AGREEMENT

SIGNATURE PAGE

CREDIT SUISSE AG, NY BRANCH
By:	/s/ Doreen Barr
	Name: Doreen Barr
	Title: Authorized Signatory
By:	/s/ Michael Dieffenbacher
	Name: Michael Dieffenbacher
	Title: Authorized Signatory

COLUMBIA FUNDS 2021

AMENDED AND RESTATED CREDIT AGREEMENT

SIGNATURE PAGE

MORGAN STANLEY BANK, N.A.
By:	/s/ Michael King
	Name: Michael King
	Title: Authorized Signatory

COLUMBIA FUNDS 2021

AMENDED AND RESTATED CREDIT AGREEMENT

SIGNATURE PAGE

GOLDMAN SACHS BANK USA
By:	/s/ Rebecca Kratz
	Name: Rebecca Kratz
	Title: Authorized Signatory

SCHEDULE I

REGISTRANTS & BORROWERS¹

Columbia Funds Series Trust II

Columbia Capital Allocation Aggressive Portfolio

Columbia Capital Allocation Conservative Portfolio

Columbia Capital Allocation Moderate Portfolio

Columbia Commodity Strategy Fund

Columbia Disciplined Core Fund

Columbia Disciplined Growth Fund

Columbia Disciplined Value Fund

Columbia Dividend Opportunity Fund

Columbia Emerging Markets Bond Fund

Columbia Flexible Capital Income Fund

Columbia Floating Rate Fund

Columbia Global Value Fund (f/k/a Columbia Global Equity Value Fund)

Columbia Global Opportunities Fund

Columbia Government Money Market Fund

Columbia High Yield Bond Fund

Columbia Income Builder Fund

Columbia Income Opportunities Fund

Columbia Large Cap Value Fund

Columbia Limited Duration Credit Fund

Columbia Minnesota Tax-Exempt Fund

Columbia Mortgage Opportunities Fund

Columbia Overseas Core Fund

Columbia Quality Income Fund

Columbia Select Global Equity Fund

Columbia Select Large Cap Value Fund

Columbia Select Small Cap Value Fund

Columbia Seligman Technology and Information Fund (f/k/a Columbia Seligman Communications and Information Fund)

Columbia Seligman Global Technology Fund

Columbia Short-Term Cash Fund

Columbia Strategic Municipal Income Fund

Multi-Manager Value Strategies Fund

Columbia Funds Variable Series Trust II

Columbia Variable Portfolio – Balanced Fund

Columbia Variable Portfolio – Commodity Strategy Fund

Columbia Variable Portfolio – Core Equity Fund

Columbia Variable Portfolio – Disciplined Core Fund

Columbia Variable Portfolio – Dividend Opportunity Fund

¹  Registrants, including Registrants that are also Borrowers, are designated in bold type face; each Borrower that is a series is listed below the name of the Registrant that acts on such Borrower’s behalf.

Columbia Variable Portfolio – Emerging Markets Bond Fund

Columbia Variable Portfolio – Emerging Markets Fund

Columbia Variable Portfolio – Global Strategic Income Fund

Columbia Variable Portfolio – Government Money Market Fund

Columbia Variable Portfolio – High Yield Bond Fund

Columbia Variable Portfolio – Income Opportunities Fund

Columbia Variable Portfolio – Intermediate Bond Fund

Columbia Variable Portfolio – Large Cap Growth Fund

Columbia Variable Portfolio – Large Cap Index Fund

Columbia Variable Portfolio – Limited Duration Credit Fund

Columbia Variable Portfolio – Mid Cap Growth Fund

Columbia Variable Portfolio – Overseas Core Fund

Columbia Variable Portfolio – Select Large Cap Equity Fund

Columbia Variable Portfolio – Select Large Cap Value Fund

Columbia Variable Portfolio – Select Mid Cap Value Fund

Columbia Variable Portfolio – Select Small Cap Value Fund

Columbia Variable Portfolio – Seligman Global Technology Fund

Columbia Variable Portfolio – U.S. Government Mortgage Fund

CTIVP – American Century Diversified Bond Fund

CTIVP – BlackRock Global Inflation-Protected Securities Fund

CTIVP – CenterSquare Real Estate Fund    

CTIVP – Loomis Sayles Growth Fund

CTIVP – MFS Value Fund

CTIVP – Morgan Stanley Advantage Fund

CTIVP – T. Rowe Price Large Cap Value Fund    

CTIVP – TCW Core Plus Bond Fund    

CTIVP – Victory Sycamore Established Value Fund

CTIVP – Wells Fargo Short Duration Government Fund

CTIVP – Westfield Mid Cap Growth Fund

Variable Portfolio – Aggressive Portfolio

Variable Portfolio – Conservative Portfolio

Variable Portfolio – Managed Volatility Moderate Growth Fund

Variable Portfolio – Moderate Portfolio

Variable Portfolio – Moderately Aggressive Portfolio

Variable Portfolio – Moderately Conservative Portfolio

Variable Portfolio – Partners Core Bond Fund

Variable Portfolio – Partners Core Equity Fund

Variable Portfolio – Partners International Core Equity Fund

Variable Portfolio – Partners International Growth Fund

Variable Portfolio – Partners International Value Fund

Variable Portfolio – Partners Small Cap Growth Fund

Variable Portfolio – Partners Small Cap Value Fund

Columbia Funds Series Trust

Columbia California Intermediate Municipal Bond Fund

Columbia Capital Allocation Moderate Aggressive Portfolio

Columbia Capital Allocation Moderate Conservative Portfolio

Columbia Convertible Securities Fund

Columbia Large Cap Enhanced Core Fund

Columbia Large Cap Growth Opportunity Fund

Columbia Large Cap Index Fund

Columbia Mid Cap Index Fund

Columbia North Carolina Intermediate Municipal Bond Fund

Columbia Overseas Value Fund

Columbia Select Large Cap Equity Fund

Columbia Select Mid Cap Value Fund

Columbia Short Term Bond Fund

Columbia Short Term Municipal Bond Fund

Columbia Small Cap Index Fund

Columbia Small Cap Value Fund II

Columbia South Carolina Intermediate Municipal Bond Fund

Columbia Virginia Intermediate Municipal Bond Fund

Columbia Funds Series Trust I

Columbia Adaptive Retirement 2020 Fund

Columbia Adaptive Retirement 2025 Fund

Columbia Adaptive Retirement 2030 Fund

Columbia Adaptive Retirement 2035 Fund

Columbia Adaptive Retirement 2040 Fund

Columbia Adaptive Retirement 2045 Fund

Columbia Adaptive Retirement 2050 Fund

Columbia Adaptive Retirement 2055 Fund

Columbia Adaptive Retirement 2060 Fund

Columbia Adaptive Risk Allocation Fund

Columbia Balanced Fund

Columbia Bond Fund

Columbia Connecticut Intermediate Municipal Bond Fund

Columbia Contrarian Core Fund

Columbia Corporate Income Fund

Columbia Dividend Income Fund

Columbia Emerging Markets Fund

Columbia Global Technology Growth Fund

Columbia Greater China Fund

Columbia High Yield Municipal Fund

Columbia Intermediate Municipal Bond Fund

Columbia International Dividend Income Fund

Columbia Large Cap Growth Fund

Columbia Massachusetts Intermediate Municipal Bond Fund

Columbia Mid Cap Growth Fund

Columbia Multi Strategy Alternatives Fund

Columbia New York Intermediate Municipal Bond Fund

Columbia Oregon Intermediate Municipal Bond Fund

Columbia Real Estate Equity Fund

Columbia Select Large Cap Growth Fund

Columbia Small Cap Growth Fund

Columbia Small Cap Value Fund I

Columbia Solutions Aggressive Portfolio

Columbia Solutions Conservative Portfolio

Columbia Strategic California Municipal Income Fund

Columbia Strategic Income Fund

Columbia Strategic New York Municipal Income Fund

Columbia Tax-Exempt Fund

Columbia Total Return Bond Fund

Columbia U.S. Social Bond Fund

Columbia U.S. Treasury Index Fund

CMG Ultra Short Term Bond Fund

Multi-Manager Alternative Strategies Fund

Multi-Manager Directional Alternative Strategies Fund

Multi-Manager Growth Strategies Fund

Multi-Manager International Equity Strategies Fund

Multi-Manager Small Cap Equity Strategies Fund

Multi-Manager Total Return Bond Strategies Fund

Multisector Bond SMA Completion Portfolio

Overseas SMA Completion Portfolio

Columbia Funds Variable Insurance Trust

Columbia Variable Portfolio – Contrarian Core Fund

Columbia Variable Portfolio – Long Government/Credit Bond Fund

Columbia Variable Portfolio – Small Cap Value Fund

Columbia Variable Portfolio – Small Company Growth Fund

Columbia Variable Portfolio – Strategic Income Fund

Variable Portfolio – Managed Risk Fund    

Variable Portfolio – Managed Risk U.S. Fund

Variable Portfolio – Managed Volatility Conservative Fund    

Variable Portfolio – Managed Volatility Conservative Growth Fund

Variable Portfolio – Managed Volatility Growth Fund    

Variable Portfolio – U.S. Flexible Conservative Growth Fund

Variable Portfolio – U.S. Flexible Growth Fund

Variable Portfolio – U.S. Flexible Moderate Growth Fund

Columbia ETF Trust I

Columbia Diversified Fixed Income Allocation ETF

Columbia Multi-Sector Municipal Income ETF

Columbia Research Enhanced Core ETF

Columbia Research Enhanced Value ETF

Columbia Short Duration Bond ETF

Columbia Sustainable International Equity Income ETF

Columbia Sustainable U.S. Equity Income ETF

Columbia ETF Trust II

Columbia EM Core ex-China ETF

Columbia Emerging Markets Consumer ETF

Columbia India Consumer ETF

Columbia Acorn Trust

Columbia Acorn European Fund

Columbia Acorn Fund

Columbia Acorn International

Columbia Acorn International Select

Columbia Acorn USA

Columbia Thermostat Fund

Wanger Advisors Trust

Wanger International

Wanger Select

Wanger USA

SCHEDULE Ia

DESIGNATED BORROWERS,

DESIGNATED PERCENTAGES

AND PRO RATA ALLOCATIONS

OMITTED

SCHEDULE II

COMMITMENTS

OMITTED

SCHEDULE III

LIST OF INVESTMENT MANAGEMENT AGREEMENTS

Amended and Restated Management Agreement dated as of October 25, 2015, between Columbia Management Investment Advisers, LLC and Columbia Funds Series Trust I and Columbia Funds Variable Insurance Trust on behalf of their underlying series listed in Schedule A thereto, Schedules A and B last amended on August 7, 2019

Amended and Restated Management Agreement dated as of April 25, 2016, between Columbia Management Investment Advisers, LLC and Columbia Funds Series Trust I and Columbia Funds Variable Insurance Trust on behalf of their underlying series listed in Schedule A thereto, Schedules A and B last amended June 15, 2021

Amended and Restated Management Agreement dated as of April 25, 2016, between Columbia Management Investment Advisers, LLC and Columbia Funds Series Trust II, Columbia Funds Variable Series Trust II, and Columbia Funds Series Trust on behalf of their underlying series listed in Schedule A thereto, Schedules A and B last amended June 15, 2021

Investment Management Services Agreement as of April 19, 2016, between Columbia Management Investment Advisers, LLC and Columbia ETF Trust I on behalf of their underlying series listed in Schedule A thereto, Schedule A last amended September 17, 2021

Amended and Restated Management Agreement dated as of November 15, 2017, between Columbia Management Investment Advisers, LLC and Columbia Funds Series Trust II, Columbia Funds Variable Series Trust II, and Columbia Funds Series Trust on behalf of their underlying series listed in Schedule A thereto, Schedules A and B last amended July 1, 2020

Investment Management Services Agreement as of September 1, 2016, between Columbia Management Investment Advisers, LLC and Columbia ETF Trust II on behalf of their underlying series listed in Schedule A thereto, Schedule A last amended June 21, 2019

Investment Advisory Agreement between Columbia Acorn Trust and Columbia Wanger Asset Management, LLC, dated May 27, 2010, Schedules I and II last amended June 8, 2011

Investment Advisory Agreement between Wanger Advisors Trust and Columbia Wanger Asset Management, LLC, dated May 27, 2010

SCHEDULE IV

LIST OF CUSTODY AGREEMENTS

Second Amended and Restated Master Global Custody Agreement, dated as of March 7, 2011, between JPMorgan Chase Bank, N.A. and the Columbia Funds, with Appendix A last amended October 1, 2021.

Custody Agreement among JPMorgan Chase Bank, N.A., Columbia Acorn Trust and Wanger Advisors Trust dated December 15, 2010, effective July 22, 2011, with Addendums dated July 14, 2011.

Custody Agreement, dated as of January 18, 2019, between The Bank of New York Mellon and the underlying funds of Columbia ETF Trust I and Columbia ETF Trust II, with Schedule I last amended August 20, 2021.

Foreign Custody Master Agreement, dated as of January 18, 2019, between The Bank of New York Mellon and the underlying funds of Columbia ETF Trust I and Columbia ETF Trust I, with Schedule I last amended August 20, 2021.

SCHEDULE V

LIST OF PRIME BROKER AGREEMENTS

Institutional Account Agreement, dated as of April 18, 2012, between Active Portfolios Multi-Manager Alternative Strategies Fund (now known as Multi-Manager Alternative Strategies Fund), a series of Columbia Funds Series Trust I and J.P. Morgan Clearing Corp., J.P. Morgan Securities LLC and certain of their affiliates.

Institutional Account Agreement, dated as of September 29, 2016, between Active Portfolios Multi-Manager Directional Alternatives Fund (now known as Multi-Manager Directional Alternative Strategies Fund), a series of Columbia Funds Series Trust I and J.P. Morgan Clearing Corp., J.P. Morgan Securities LLC and certain of their affiliates.

Customer Prime Broker Account Agreement, dated as of September 29, 2016, between Active Portfolios Multi-Manager Directional Alternative Fund (now known as Multi-Manager Directional Alternatives Strategies Fund), a series of Columbia Funds Series Trust I and Morgan Stanley and Co. LLC.

Institutional Account Agreement, dated as of September 15, 2017, between Columbia Global Opportunities Fund, a series of Columbia Funds Series Trust II and J.P. Morgan Securities LLC and certain of its affiliates.

Customer Prime Broker Account Agreement, dated as of April 23, 2012, between Active Portfolio Multi-Manager Alternative Strategies Fund (now known as Multi-Manager Alternative Strategies Fund), a series of Columbia Funds Series Trust I and Goldman, Sachs & Co.

SCHEDULE 5.1

Web Addresses For Annual, Semi-Annual and Quarterly Reports

https://www.columbiathreadneedleus.com/investor/resources/literature/

http://www.columbiathreadneedleetf.com/

http://www.sec.gov

SCHEDULE 9.20

REPRESENTATIONS, COVENANTS AND EVENTS OF DEFAULT

APPLICABLE TO BORROWERS WITH MAURITIUS SUBSIDIARIES

1. In order to induce the Lenders and the Administrative Agent to enter into this Agreement and to make Loans hereunder, in addition to the representations and warranties set forth in Section 3, each Mauritius Parent Borrower represents and warrants to the Administrative Agent and each Lender as follows:

(a) Existence. Such Mauritius Parent Borrower’s Mauritius Designated Subsidiary is duly organized, validly existing and in good standing under the laws of the Republic of Mauritius. Such Mauritius Designated Subsidiary is duly qualified to do business and in good standing in each other jurisdiction in which such qualification is required by applicable law, except to the extent the failure to be so qualified or in good standing could not have a Material Adverse Effect on such Mauritius Parent Borrower.

(b) Ownership. Such Mauritius Parent Borrower has no Subsidiaries or any equity investment or interest in any other Person other than (i) portfolio securities that have been acquired in the ordinary course of business, and (ii) its Mauritius Designated Subsidiary(ies). Such Mauritius Parent Borrower holds all of the issued and outstanding shares of stock of its Mauritius Designated Subsidiary(ies) and such shares are not subject to any Lien, pledge or other encumbrance except as may be permitted by Section 6.3.

2. Until the expiration or termination of the Commitments and until all obligations of the Borrowers under the Loan Documents have been paid or performed in full, in addition to the covenants set forth in Sections 5 and 6, each Mauritius Parent Borrower shall perform the following obligations:

(a) [Reserved].

(b) Existence. Such Mauritius Parent Borrower shall (i) maintain and preserve its Mauritius Designated Subsidiary’s existence and good standing in the Republic of Mauritius and, except to the extent the failure to be so qualified or in good standing could not have a Material Adverse Effect on such Mauritius Parent Borrower, its qualification to do business and good standing in each other jurisdiction in which such qualification is required by applicable law, and (ii) maintain and preserve all rights, privileges, licenses, copyrights, trademarks, trade names, franchises and other authority of such Mauritius Designated Subsidiary to the extent material and necessary for the conduct of such Mauritius Designated Subsidiary’s business in the ordinary course, unless the failure to so maintain and preserve could not reasonably be expected to have a Material Adverse Effect on such Mauritius Parent Borrower. Notwithstanding the foregoing provisions of this Schedule 9.20 and Section 6.5 of the Agreement, a Mauritius Designated Subsidiary shall, without the consent of the Lenders, be permitted to liquidate, wind up or dissolve; provided that (i) the net asset value of such Mauritius Designated Subsidiary does not exceed 1% of the total net asset value of the relevant Mauritius Parent Borrower, and (ii) the Mauritius Parent Borrower parent to such Mauritius Designated Subsidiary shall deliver to the Administrative Agent notice of such dissolution promptly following the effectiveness thereof.

(c) Asset Coverage Ratio. Such Borrower shall at all times maintain an Asset Coverage Ratio of its Designated Borrower Asset Coverage Ratio Percentage or such other more restrictive ratio as may be set forth in the most recent Prospectus or most recent SAI (if applicable) to such Mauritius Parent Borrower.

(d) Compliance With Laws. Such Mauritius Parent Borrower will cause its Mauritius Designated Subsidiary to comply in all respects with all applicable laws, ordinances, rules, regulations and requirements of governmental authorities and the exchange on which its shares are traded, if any, except where (a) the necessity of compliance therewith is contested in good faith by appropriate proceedings, (b) exemptive relief has been obtained therefrom and remains in effect or (c) the violation thereof could not reasonably be expected to have a Material Adverse Effect on such Mauritius Designated Subsidiary or such Mauritius Parent Borrower. Such Mauritius Parent Borrower will cause its Mauritius Designated Subsidiary to file or cause to be filed all federal and other tax returns, reports and declarations required by all relevant jurisdictions on or before the due dates for such returns, reports and declarations and will pay all taxes and other governmental assessments and charges as and when they become due (except those that are being contested in good faith by such Mauritius Designated Subsidiary and as to which such Mauritius Designated Subsidiary has established appropriate reserves on its books and records or where the failure to file any such return or report or the nonpayment of any such taxes or charges could not reasonably be expected to have a Material Adverse Effect on such Mauritius Parent Borrower).

(e) Ownership. Such Mauritius Parent Borrower will own one hundred percent (100%) of the Equity Interests of its Mauritius Designated Subsidiary. For purposes of this clause (e), “Equity Interests” shall mean all shares, rights to purchase, options, warrants, general, limited or limited liability partnership interests, member interests, participation or other equivalents of or interest in (regardless of how designated) equity of such Mauritius Designated Subsidiary, whether voting or nonvoting, including, without limitation, common stock, preferred stock, convertible securities or any other equity security in such Mauritius Designated Subsidiary.

(f) Distributions from Subsidiary. Such Mauritius Parent Borrower will not cause or permit its Mauritius Designated Subsidiary’s organizational documents or any instrument, agreement or document executed by or on behalf of its Mauritius Designated Subsidiary or such Mauritius Parent Borrower, or by which such Mauritius Designated Subsidiary or such Mauritius Parent Borrower is bound, to contain any restriction on such Mauritius Designated Subsidiary’s right or ability to make dividends, distributions or loans of any kind, or otherwise to transfer any assets or funds from such Subsidiary, to such Mauritius Parent Borrower, other than, in the case of any organizational documents, restrictions required by applicable law.

(g) Limitation on Indebtedness. At any time during which such Mauritius Parent Borrower has any Loan outstanding, such Mauritius Parent Borrower will not cause or permit its Mauritius Designated Subsidiary to create, incur, assume or suffer to exist any Indebtedness constituting Senior Securities in an amount exceeding 10% of such Mauritius Designated Subsidiary’s net asset value.

3. In addition to the Events of Default set forth in Section 7 each of the following shall constitute an Event of Default with respect to each Mauritius Parent Borrower:

(a) Such Mauritius Parent Borrower shall default in the performance of its agreements under (i) Section 2(e) or 2(g) of this Schedule 9.20, (ii) Section 2(c) of this Schedule 9.20, and, in the case of Section 2(c), such default is not cured within three (3) Business Days or (iii) Section 2(b)(i) of this Schedule 9.20, and, in the case of Section 2(b)(i), such default is not cured within five (5) Business Days.

EXHIBIT 2.5(e)

FORM OF NOTE

	New York, New York
$		, 20

FOR VALUE RECEIVED, [Registrant], on behalf of [Borrower] (the “Borrower”), hereby unconditionally promises to pay to the order of __________________________, at the office of JPMORGAN CHASE BANK, N.A. as administrative agent for the Lenders (the “Lenders”) under the Credit Agreement, as hereinafter defined (in such capacity, the “Administrative Agent”), in lawful money of the United States of America and in immediately available funds, on each Maturity Date the principal amount of (a)__________ DOLLARS ($______________), or, if less (b) the aggregate unpaid principal amount of all Loans made by the holder of this Note to the Borrower pursuant to Sections 2.1, 2.14 and 2.15 of the Credit Agreement, as hereinafter defined.

The undersigned further agrees to pay interest in like money at such office on the unpaid principal amount hereof from time to time from the Closing Date at the applicable rates per annum set forth in Section 2.7 of the Credit Agreement referred to below until any such amount shall become due and payable (whether at the stated maturity, by acceleration or otherwise), and thereafter on such overdue amount at the rate per annum set forth in Section 2.7(b) of the Credit Agreement until paid in full (both before and after judgment). Interest shall be payable in arrears on each applicable Interest Payment Date, commencing on the first such date to occur after the date hereof and terminating upon payment (including prepayment) in full of the unpaid principal amount hereof; provided that interest accruing on any overdue amount shall be payable on demand.

The holder of this Note is authorized to endorse on the schedule annexed hereto and made a part hereof the date and amount of each Loan made to the Borrower pursuant to the Credit Agreement and the date and amount of each payment or prepayment of principal thereof. Each such endorsement shall constitute prima facie evidence of the accuracy of the information endorsed. The failure to make any such endorsement shall not affect the obligations of the Borrower in respect of such Loan.

This Note (a) is one of the Notes referred to in the Amended and Restated Credit Agreement, dated as of [_________] (as amended, supplemented or otherwise modified from time to time, the “Credit Agreement”), among the Registrants identified therein on behalf of the Borrowers, the Lenders, the syndication agents party thereto and the Administrative Agent, (b) is subject to the provisions of the Credit Agreement and (c) is subject to optional and mandatory prepayment in whole or in part as provided in the Credit Agreement.

Upon the occurrence of one or more Events of Default, all amounts then remaining unpaid on this Note shall become, or may be declared to be, immediately due and payable, all as provided in the Credit Agreement.

All parties now and hereafter liable with respect to this Note, whether maker, principal, surety, guarantor, endorser or otherwise, hereby waive presentment, demand, protest and all other notices of any kind.

Unless otherwise defined herein, terms defined in the Credit Agreement and used herein shall have the meanings given to them in the Credit Agreement.

THIS NOTE SHALL BE GOVERNED BY, AND CONSTRUED AND INTERPRETED IN ACCORDANCE WITH, THE SUBSTANTIVE LAWS OF THE STATE OF NEW YORK.

[NAME OF REGISTRANT]
By:
	Name:
	Title:

Schedule A to Note

LOANS AND REPAYMENTS OF LOANS

DATE AMOUNT OF LOANS AMOUNT OF PRINCIPAL OF
LOANS REPAID UNPAID
PRINCIPAL
BALANCE
OF LOANS NOTATION MADE BY

EXHIBIT 2.16(a)

FORM OF DESIGNATION OF NEW BORROWERS

_________ __, [     ]                                

JPMORGAN CHASE BANK, N.A., as Administrative Agent

Each of the Lenders under the

Credit Agreement identified below

Ladies and Gentlemen:

Reference is made to that certain Amended and Restated Credit Agreement, dated as of [_________] (as amended, restated, supplemented or otherwise modified from time to time, the “Agreement”) among (i) certain registered investment companies (each, a “Registrant”, and collectively, the “Registrants”), each of which on behalf of certain of its respective series set forth beneath such Registrant’s name on Schedule [_] thereto (each of which series is, individually, a “Borrower” and, collectively, the “Borrowers”), (ii) the several banks and other financial institutions from time to time parties thereto (the “Lenders”), and (iii) JPMorgan Chase Bank, N.A., a national banking association, as administrative agent and as documentation agent for the Lenders thereunder (in such capacity, the “Administrative Agent”). Capitalized terms used herein and not otherwise defined herein shall have the meanings ascribed to them in the Agreement.

The undersigned Registrant or new registered investment company (each, a “Requesting Registrant”), on behalf of the series set forth beneath its name (each such series a “New Borrower”), hereby requests that each New Borrower be admitted as an additional Borrower under the Agreement.

The Requesting Registrant and each New Borrower hereby represent and warrant to the Administrative Agent and each Lender that as of [ ] and after giving effect to the admission of each New Borrower as an additional Borrower under the Agreement: (i) the representations and warranties set forth in Section 3 of the Agreement are true and correct with respect to it; (ii) it is in compliance in all material respects with all the terms and provisions set forth in the Agreement; (iii) no Default or Event of Default with respect to it has occurred and is continuing.

Each New Borrower agrees to be bound by the terms and conditions of the Agreement in all respects as a Borrower thereunder and hereby assumes all of the obligations of a Borrower thereunder.

Please indicate your assent to the admission of each New Borrower as an additional Borrower under the Agreement by executing the [ ] dated as of the date hereof.

[SIGNATORIES]

EXHIBIT 9.6 (c)

FORM OF ASSIGNMENT AND ACCEPTANCE

Reference is made to the Amended and Restated Credit Agreement, dated as of [_________] (as amended, restated, supplemented or otherwise modified from time to time, the “Credit Agreement”) among (i) certain registered investment companies (each, a “Registrant”, and collectively, the “Registrants”), each of which on behalf of certain of its respective series set forth beneath such Registrant’s name on Schedule [_] thereto (each of which series, is, individually, a “Borrower” and, collectively, the “Borrowers”), (ii) the several banks and other financial institutions from time to time parties thereto (the “Lenders”), and (iii) JPMorgan Chase Bank, N.A., a national banking association, as administrative agent and as documentation agent for the Lenders thereunder (in such capacity, the “Administrative Agent”). Unless otherwise defined herein, terms defined in the Credit Agreement and used herein shall have the meanings given to them in the Credit Agreement.

                                                      (the “Assignor”) and                                                       (the “Assignee”) agree as follows:

1. The Assignor hereby irrevocably sells and assigns to the Assignee without recourse to the Assignor, and the Assignee hereby irrevocably purchases and assumes from the Assignor without recourse to the Assignor, as of the Effective Date (as defined below) the interest described in Schedule 1 hereto (the “Assigned Interest”) in and to the Assignor’s rights and obligations under the Credit Agreement.

2. The Assignor (a) makes no representation or warranty and assumes no responsibility with respect to or in any connection with the Credit Agreement or with respect to the execution, legality, validity, enforceability, genuineness, sufficiency or value of the Credit Agreement, any other Loan Document or any other instrument or document furnished pursuant thereto, other than that the Assignor has not created any adverse claim upon the interest being assigned by it hereunder and that such interest is free and clear of any such adverse claim; (b) makes no representation or warranty and assumes no responsibility with respect to the financial condition of any Borrower or any other obligor or the performance or observance by any Borrower or any other obligor of any of their respective obligations under the Credit Agreement or any other Loan Document or any other instrument or document furnished pursuant hereto or thereto; and (c) attaches any Notes held by it evidencing the Assigned Interest and (i) requests that the Administrative Agent, upon request by the Assignee, exchange the attached Notes for a new Note or Notes payable to the Assignee and (ii) if the Assignor has retained any interest in the Assigned Interest, requests that the Administrative Agent exchange the attached Notes for a new Note or Notes payable to the Assignor, in each case in amounts which reflect the assignment being made hereby (and after giving effect to any other assignments which have become effective on the Effective Date).

3. The Assignee (a) represents and warrants that it is legally authorized to enter into this Assignment and Acceptance; (b) confirms that it has received a copy of the Credit Agreement, together with copies of such other documents and information as it has deemed appropriate to make its own credit analysis and decision to enter into this Assignment and Acceptance; (c) agrees that it will, independently and without reliance upon the Assignor, the Administrative Agent or any other Lender and based on such documents and information as it shall deem appropriate at the time, continue to make its own credit decisions in taking or not taking action under the Credit Agreement, the other Loan Documents or any other instrument or document furnished pursuant hereto or thereto; (d) appoints and authorizes the Administrative Agent to take such action as agent on its behalf and to exercise such powers and discretion under the Credit Agreement, the other Loan Documents or any other instrument or document furnished pursuant hereto or thereto as are delegated to the Administrative Agent by the terms thereof, together with such powers as are incidental thereto; and (e) agrees that it will perform in accordance with its terms all the obligations which by the terms of the Credit Agreement are required to be performed by it as a Lender including, if it is organized under the laws of a jurisdiction outside the United States, its obligation pursuant to Section 2.11(b) of the Credit Agreement.

4. The effective date of this Assignment and Acceptance shall be _________ (the “Effective Date”). Following the execution of this Assignment and Acceptance, it will be delivered to the Administrative Agent for acceptance by it and recording by the Administrative Agent pursuant to the Credit Agreement, effective as of the Effective Date (which shall not, unless otherwise agreed to by the Administrative Agent, be earlier than five Business Days after the date of such acceptance and recording by the Administrative Agent).

5. Upon such acceptance and recording, from and after the Effective Date, the Administrative Agent shall make all payments in respect of the Assigned Interest (including payments of principal, interest, fees and other amounts) to the Assignee whether such amounts have accrued prior to the Effective Date or accrue subsequent to the Effective Date. The Assignor and the Assignee shall make all appropriate adjustments in payments by the Administrative Agent for periods prior to the Effective Date or with respect to the making of this assignment directly between themselves.

6. From and after the Effective Date, (a) the Assignee shall be a party to the Credit Agreement and, to the extent provided in this Assignment and Acceptance, have the rights and obligations of a Lender thereunder and under the other Loan Documents and shall be bound by the provisions thereof and (b) the Assignor shall, to the extent provided in this Assignment and Acceptance, relinquish its rights (except under Sections 2.10, 2.11 and 9.5 of the Credit Agreement in respect of the period prior to the Effective Date) be released from its obligations under the Credit Agreement.

7. This Assignment and Acceptance shall be governed by and construed in accordance with the substantive laws of the State of New York.

IN WITNESS WHEREOF, the parties hereto have caused this Assignment and Acceptance to be executed as of the date first above written by their respective duly authorized officers.

[NAME OF ASSIGNEE]		[NAME OF ASSIGNOR]
By:		By:
	Name:		Name:
	Title:		Title:
Accepted and Consented To:
JPMORGAN CHASE BANK, N.A.
as a Lender and as Administrative Agent
By:
	Name:
	Title:
If Required by Credit Agreement:
[REGISTRANT], on behalf
of itself and the Borrowers
By:
	Name:
	Title:

SCHEDULE 1 TO ASSIGNMENT AND ACCEPTANCE

RELATING TO THE AMENDED AND RESTATED CREDIT AGREEMENT

DATED AS OF [_________]

Name of Assignor:

Name of Assignee:

Effective Date of Assignment:

Principal Amount Assigned	Commitment Percentage Assigned1
$________	$________

¹  Calculate the Commitment Percentage that is assigned to at least 15 decimal places and show as a percentage of the aggregate commitments of all Lenders.

EX-99.(I)

                

April 27, 2022

Columbia Acorn Trust

71 S. Wacker Drive, 25th Floor

Chicago, Illinois 60606

Ladies and Gentlemen:

We have acted as counsel to Columbia Acorn Trust, a business trust formed under the laws of the Commonwealth of Massachusetts (the “Trust”), in connection with the filing with the Securities and Exchange Commission (the “SEC”) of Post-Effective Amendment No. 115 to the Trust’s Registration Statement on Form N-1A (File Nos. 002-34223; 811-01829) (the “Post-Effective Amendment”), registering an indefinite number of shares of beneficial interest of each class of shares of Columbia Acorn Fund, Columbia Acorn USA, Columbia Acorn International, Columbia Acorn International Select, Columbia Thermostat Fund and Columbia Acorn European Fund, each a series of the Trust (all such shares, collectively, the “Shares”), under the Securities Act of 1933, as amended (the “1933 Act”).

You have requested our opinion as to the matters set forth below in connection with the filing of the Post-Effective Amendment. For purposes of rendering that opinion, we have examined the Post-Effective Amendment, the Declaration of Trust, as amended, the By-Laws of the Trust, and the actions by the board of trustees of the Trust that provide for the issuance of the Shares, and we have made such other investigation as we have deemed appropriate. We have examined and relied upon certificates of public officials and, as to certain matters of fact that are material to our opinion, we have also relied on a certificate of the Secretary of the Trust. In rendering our opinion, we also have made the assumptions that are customary in opinion letters of this kind. We have not verified any of those assumptions.

Based upon and subject to the foregoing, we are of the opinion that:

(1) The Shares being registered pursuant to the Post-Effective Amendment have been duly authorized for issuance by the Trust; and

(2) When issued and paid for at net asset value as contemplated by the Post-Effective Amendment, the Shares will be validly issued, fully paid, and non-assessable. In this regard, however, we note that the Trust is a Massachusetts business trust and, under certain circumstances, shareholders of a Massachusetts business trust could be held personally liable for the obligations of the trust.

Our opinion, as set forth herein, is based on the facts in existence and the laws in effect on the date hereof and is limited to the Federal laws of the United States and the laws of the Commonwealth of Massachusetts. We are members of the Bar of the District of Columbia and our opinion, as it relates to the laws of the Commonwealth of Massachusetts, is based solely on

April 27, 2022

Page 2

our review of the laws, and, where applicable, published cases, rules or regulations relating thereto, of the Commonwealth of Massachusetts that, in our experience, generally are applicable to the issuance of shares by entities such as the Trust.

This opinion is rendered solely in connection with the filing of the Post-Effective Amendment. We hereby consent to the filing of this opinion with the SEC in connection with the Post-Effective Amendment. In giving our consent we do not thereby admit that we are in the category of persons whose consent is required under Section 7 of the 1933 Act or the rules and regulations of the SEC thereunder.

Very truly yours,

/s/ Perkins Coie LLP

Perkins Coie LLP

EX-99.(J)

CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We hereby consent to the incorporation by reference in this Registration Statement on Form N-1A of Columbia Acorn Trust of our reports dated February 18, 2022, relating to the financial statements and financial highlights, which appear in the Annual Reports on Form N-CSR of the funds indicated in Appendix A for the year ended December 31, 2021. We also consent to the references to us under the headings “Financial Highlights” and “Independent Registered Public Accounting Firm” in such Registration Statement.

/s/PricewaterhouseCoopers LLP

Minneapolis, Minnesota

April 27, 2022

Appendix A

Fund Name

Columbia Acorn European Fund^SM

Columbia Acorn^® Fund

Columbia Acorn International^®

Columbia Acorn International Select^SM

Columbia Acorn USA^®

Columbia Thermostat Fund^SM

EX-99.(P)(1)

COLUMBIA THREADNEEDLE INVESTMENTS

GLOBAL PERSONAL ACCOUNT DEALING AND CODE OF ETHICS

Policy Type	Global Policy
Last Review Date	December 2021
Applicable Global Regulatory Authorities	SEC Rule 204A-1 of the Advisers Act SEC Rule 17j-1 of the Investment Company Act FCA Rule Conduct of Business Sourcebook (COBS) 11.7 Securities and Futures Act MAS guidelines on Risk Management Practices-Internal Controls MAS Guidelines on Individual Accountability and Conduct Code of Conduct for Persons licensed by the Securities and Futures Commission Section 13 of the Bank Holding Company Act known as the “Volcker Rule” JFSA “Comprehensive Guideline for Supervision of Financial Instruments Business Operators, etc.” Japan Investment Advisors Association self-regulation
Related Policies	See Appendix C-Other Policies Applicable to Covered Persons
Applicability and Scope	All Covered Persons and certain household members, trusteeships and executorships of Covered Persons. See Appendix B-Entities That Have Adopted Policy

1. POLICY STATEMENT

1.1. Keys Points

Standard of Business Conduct: The conduct of personal dealings in investments by Covered Persons (See Appendix A-Definitions for Covered Persons definition) employed by or affiliated with the Ameriprise Global Asset Management Entities¹ (the “Firms”) is a matter of the utmost importance to the organization, its clients, its regulators and to employees themselves. It is essential that the Firms appropriately manage access to privileged information concerning clients’ portfolios, the Firms’ trading intentions and trading activities, and that the Firms discharge their duties in a way that does not harm the interests of clients, the Firms or breach any legal or regulatory requirements. It is important that the Firms are not seen to act on privileged information for personal gain.

Duty Owed to Clients: Various regulations applicable to the Firms impose a fiduciary duty to act in the exclusive best interest of their clients at all times recognizing their role as a “Trusted Adviser”. A number of specific obligations flow from the duty that is owed to clients, including:

• To act solely in the best interests of clients at all times.

• To make full and fair disclosure of all material facts, particularly where the Firms’ interests may conflict with those of its clients.

• To act in a manner which satisfies the fiduciary duty owed to clients.

• To refrain from favouring the interest of a particular client over the interests of another client.

• To keep all information about clients (including former clients) confidential, including the client’s identity, client’s securities holdings information, and other non-public information.

• To exercise a high degree of care to ensure that adequate and accurate representations and other information is presented appropriately.

In connection with providing investment management services to clients, this includes prohibiting any activity which directly or indirectly:

• Defrauds a client in any manner.

• Misleads a client, including any statement that omits material facts.

• Operates or would operate as a fraud or deceit on a client.

• Functions as a manipulative practice with respect to a client.

• Functions as a manipulative practice with respect to securities.

Specifically, the fiduciary duty owed to clients means the following outcomes must be achieved:

• To have a reasonable, independent basis for investment advice.

• To ensure that investment advice is suitable to the client’s investment objectives, needs and circumstances.

¹  See Appendix B-Entities That Have Adopted Policy

This document is current as of the last review date but subject to change thereafter.

Columbia Threadneedle Investments (Columbia Threadneedle) is the global brand name of the Columbia and Threadneedle group of companies.

• To refrain from effecting Personal Securities Transactions inconsistent with clients’ interests.

• To obtain best execution for clients’ securities transactions.

Conflicts of Interest: All Covered Persons must be vigilant in terms of identifying circumstances that may present a conflict of interest. A conflict of interest is any situation that presents an incentive to act other than in the best interest of a client or without objectivity. A conflict of interest may arise, for example, when a Covered Person engages in a transaction that potentially favors:

• The Firms’ interests over a client’s interest

• The interest of a Covered Person over a client’s interest

• One client’s interest over another client’s interest

In addition to this Ameriprise Global Asset Management Personal Account Dealing and Code of Ethics Policy (“Policy”), the Firms have adopted various policies designed to prevent, or otherwise manage, conflicts of interest in contexts outside of personal trading. To effectively manage conflicts of interest, all Covered Persons must seek to prevent conflicts of interest, including the appearance of a conflict.

The requirements set forth in this Policy do not identify all possible conflicts of interest that may arise in relation to personal transactions. Employees are encouraged to seek assistance from their local Compliance resources (see Appendix D-Resources) whenever they have any questions concerning obligations under the Policy, including conflicts of interest situations or concerns.

Additional Standards of Conduct and Regulatory Requirements: Covered Persons must comply with other policies adopted by the individual Ameriprise Global Asset Management Entities that are intended to promote fair and ethical standards of business conduct and comply with related regulatory requirements, including the Ameriprise Financial Global Code of Conduct. (See Appendix C-Other Policies Applicable to Covered Persons).

This document is current as of the last review date but subject to change thereafter.

Columbia Threadneedle Investments (Columbia Threadneedle) is the global brand name of the Columbia and Threadneedle group of companies.

1.2. Specific Policy Requirements

This Policy applies to all Covered Persons and certain household members, Trusteeships and Executorships of Covered Persons. Covered Persons include:

• All Columbia Threadneedle employees and contractors, including employees of Columbia Wanger Asset Management (CWAM) and Lionstone.

• Any other individual with a specific role (including working on a project) which compels Covered Person status due to access to proprietary information (e.g., holdings/transactions), such as the member of a staff group that provides ongoing audit, technology, finance, compliance, or legal support to Firms.

• Any other persons that may be deemed appropriate by Compliance.

Covered Securities Transactions/Accounts: This Policy governs a Covered Person’s personal securities transactions as well as those securities transactions in which a Covered Person is deemed to have a direct or indirect Beneficial Ownership (see Appendix A-Definitions for Beneficial Ownership definition) and over which a Covered Person exercises direct or indirect influence or control (“Affiliated Accounts”). An account generally is covered by this Policy if it is:

• In the Covered Person’s name

• In the name of the Covered Person’s spouse/partner and/or any financially dependent members of the Covered Person’s household,

• Of a partnership in which the Covered Person or a member of his/her immediate family is a partner with direct or indirect investment discretion

• Of a trust in which the Covered Person (or a member of his/her immediate family) is a beneficiary and a trustee with direct or indirect investment discretion

• Of a closely held corporation in which the Covered Person or a member of his/her immediate family holds shares and have direct or indirect investment discretion

It is the responsibility of the Covered Person to seek advice in the event that it is not clear whether certain personal securities transactions are covered by this Policy.

Material Nonpublic Information: A Covered Person who is in possession of material nonpublic information (often referred to as “Inside Information”) about securities or financial instruments is prohibited from buying, selling, recommending or trading such securities or financial instruments. In addition, a Covered Person must not communicate or disclose such information to others who may misuse it. Material nonpublic information may include nonpublic information about a pooled investment vehicle (e.g., UCITS, open-end and closed-end mutual funds, and private funds) that are advised or sub-advised by the Firm. The Firms each have adopted specific policies that address these prohibitions, and set forth specific protocols for handling material nonpublic information (see Appendix C-Other Policies Applicable to Covered Persons)

This document is current as of the last review date but subject to change thereafter.

Columbia Threadneedle Investments (Columbia Threadneedle) is the global brand name of the Columbia and Threadneedle group of companies.

Disclosure of Brokerage Accounts Covered Persons must promptly disclose their brokerage accounts to their Firm’s Compliance group and ensure that each broker-dealer with which he/she maintains an account sends to the Compliance group, as soon as practicable, copies of all confirmations of securities transactions and of all monthly, quarterly and annual account statements. In order to comply with regulatory expectations concerning the monitoring of trading activity within Covered Persons’ accounts, there are requirements on where brokerage accounts may be maintained for the trading of certain types of securities. Please refer to Appendix H – Limited Choice Policy for specific information by region.

Notification of Brokerage Accounts Covered Persons must immediately report any brokerage accounts opened by completing the following steps:

• Add the account to the PTA system using the “Add Brokerage Account” functionality.

• Notify your broker of your association with Ameriprise Financial or Columbia Threadneedle. You are responsible for notifying your broker that you are affiliated with or employed by a broker/dealer and ensuring that Personal Trade Compliance is provided with duplicate statements and confirmations for your account(s).

North America employees – any brokerage account outside of Limited Choice brokers (as listed in Appendix H) for example, a brokerage account holding mutual funds only, must be approved by Personal Trade Compliance prior to establishing the account in order to comply with FINRA rule 3210.

UK/APAC employees – Employees are required to authorize the electronic feeds between the approved brokers listed in Appendix H and Columbia Threadneedle Investments.

Personal Trading Restrictions

Prohibition on “Front Running”: Covered Persons are prohibited from engaging in a Personal Securities Transaction that involves the purchase or sale of a Reportable Security when such Covered Person has knowledge that such security (1) is being considered for purchase or sale by a client account or (2) is being purchased or sold by a client account.

Prior Approval (Pre-Clearance) of Personal Security Transactions: Covered Persons must obtain approval – often referred to as pre-clearance—from Compliance prior to effecting a securities trade in most categories of investments. This pre-clearance requirement extends to securities transactions in all accounts for which the Covered Person has Beneficial Ownership (see Appendix A-Definitions). If the Covered Person receives pre-clearance approval, it is valid only for the duration of the locally defined approval period; in North America preclearance is good only for the day it is granted, in EMEA/APAC preclearance is good for the day granted and until the end of the following business day. If a Covered Person does not effect the pre-cleared personal trade(s) within that locally approved time period, the Covered Person must request and obtain pre-clearance for the proposed personal trade(s) again before the trade(s) are effected. If the Covered Person does not receive pre-clearance approval, he/she must not effect the requested Personal Securities Transaction (but may request approval on a subsequent day).

Covered Persons are required to obtain such pre-clearance approval for the majority of investments (e.g., stocks, bonds, Exchange Traded Funds (“ETFs”), closed-end funds). Please refer to Appendix E-Individual Security Requirements which identifies those categories of investments to which pre-clearance is or is not applicable.

This document is current as of the last review date but subject to change thereafter.

Columbia Threadneedle Investments (Columbia Threadneedle) is the global brand name of the Columbia and Threadneedle group of companies.

Private Placements/Limited Offerings: Investments in private placement offerings require approval by the Compliance group (e.g., private placements, non-exchange traded REITs, hedge funds, fixed income new issues, unlisted structured products, non-charity crowdfunding, etc.). If approved, the approval is good for 90 days.

Gifts and Charitable Donations: Approval is not necessary for a gift of securities to a Non-Profit Organization, but Compliance should be notified in advance and the Short-Term and 14-day Blackout rules do not apply. For gifting securities to a For-Profit Organization, individual, trust or other person or entity (other than a Non-Profit Organization), the pre-clearance requirement and 14-day Blackout rule do apply if you are purchasing the securities you intend to give. If the securities are already owned, the transfer of securities does not require pre-clearance. If you receive a gift of securities, you must update your holdings on PTA and no pre-clearance is required.

Short-Term Trading Prohibition (30 Day Holding Period)

Individual Securities at a Profit: Covered Persons are prohibited from engaging in short-term trading of Reportable Securities. This means that Covered Persons may not buy (or add to their existing position), then sell the same securities (or equivalent) within 30 calendar days if the trade would result in a gain. Covered Persons must wait until calendar day 31 (Trade Date + 30) to trade out of a position at a profit within the same account.

Covered Funds and other Pooled Investment Vehicles: A Covered Person is prohibited from short term trading in any Covered Fund (e.g., mutual fund, SICAV, OEIC, or other pooled investment vehicle, see Appendix F-Covered Funds List) held for less than 30 calendar days, or a longer time if specified in the Covered Fund’s prospectus or similar disclosure document. Covered Persons are prohibited from engaging in market timing (short-term trading) in shares of any pooled investment vehicles and must comply with the holding period policy established by any prospectus.

Transactions exempted from short-term trading prohibitions: Money market fund investments, automated investments and withdrawal programs, and Dividend Reinvestments are not subject to the 30-day holding period.

Initial Public Offerings (“IPOs”) and Limited Offerings/Private Placements:

• Equity IPOs in North America are prohibited including direct purchased programs.

• Covered Persons are required to obtain pre-clearance approval to purchase IPOs or Limited Offerings/Private Placements, including additions to existing holdings but excluding capital calls for previously approved commitments.

• Such approval will only be granted when 1) it is determined that the investment in a private fund (if a proprietary private fund) meets the applicable banking regulatory requirements² and 2) it is established that there is no conflict or appearance of a conflict with any Client or other possible impropriety (such as where the Security in the Limited Offering is appropriate for purchase by a Client, or when his/her participation in the Limited Offering is suggested by a person who has a business relationship with any such Company or expects to establish such a relationship).

• The 30-day holding period also applies to IPOs.

²  The review of applicability of banking requirements will occur during the subscription process.

This document is current as of the last review date but subject to change thereafter.

Columbia Threadneedle Investments (Columbia Threadneedle) is the global brand name of the Columbia and Threadneedle group of companies.

Cryptocurrency³:

Transactions: Transactions in cryptocurrency, such as Bitcoin, Ethereum, Lite Coin etc., do not require reporting. However, transactions in any publicly traded cryptocurrency tracker instrument, such as Grayscale’s Bitcoin Investment Trust (“GBTC”), require pre-clearance approval, must be held and traded at an approved broker (See Appendix H).

Accounts: Cryptocurrency accounts are not reportable and must be at firms that offer ONLY cryptocurrency investments. Accounts at firms that also offer brokerage options are prohibited.

Initial Coin Offerings (“ICOs”): Participation in ICOs is prohibited.

Participation in Investment Clubs:

No Covered Person may participate in private investment clubs or other similar groups.

Derivatives:

Covered Persons are strongly discouraged from investing in any form of derivative that could give rise to an open ended, unlimited liability. Most derivative trading is subject to pre-clearance requirements, option trading guidelines and the Short-Term Trading Prohibition. (See Appendix G-Options/Short Trading Guidelines).

Frequent and Unusual Trading Activity:

Compliance monitors patterns of personal trading activity and may require additional information from a Covered Person with respect to a specific trade or series of transactions. In addition, frequent personal trading activity is strongly discouraged. Although each situation is case specific, we generally review trading amounts over 25 trades per quarter for further analysis, which could result in corrective measures.

Columbia Wanger Asset Management (CWAM) Specific Trading Restrictions:

No CWAM Covered Person shall purchase any Reportable Security that is owned by a CWAM Client Account (excluding ETFs).

³  Personal Trade Compliance continues to monitor the evolving digital assets/cryptocurrency space and the impact on Covered Persons under the Policy. These requirements may change if regulatory guidance or rules should be provided. All Covered Persons are encouraged to contact Personal Trade Compliance prior to transacting in any form of digital assets/cryptocurrency to ensure compliance with the latest regulatory and firm guidance/requirements.

This document is current as of the last review date but subject to change thereafter.

Columbia Threadneedle Investments (Columbia Threadneedle) is the global brand name of the Columbia and Threadneedle group of companies.

Additional Trading Restrictions for Investment Personnel

Rules Applicable to Portfolio Managers and other Designated Covered Persons:

14 Day Blackout Period: Portfolio Managers (and other Covered Persons specifically identified by Compliance) are not permitted to transact in any security that is purchased or sold in a client account 7 calendar days before and 7 calendar days after a client account they manage trades in that same (or equivalent) security. This means a Portfolio Manager (and other Designated Covered Persons) must wait until calendar day 8 to trade the security. Application of this rule may be applied broader based on team function and location.

Because it is a Portfolio Manager’s responsibility to put his/her client’s interests ahead of his/her own, he/she may not delay taking appropriate action for a client account in order to avoid potential adverse consequences in his/her personal account. In certain limited instances, Compliance, at their discretion, may determine that a trade should be deemed to have not caused a black out violation (e.g., unexpected significant client redemption or inflow triggering a sale or purchase in all securities held in the client portfolio).

Rules Applicable to Research Analysts:

Centralised Research Analysts (those who publish research for the use by Columbia Threadneedle) are prohibited from engaging in a personal securities transaction that involves securities issued by issuers on their Coverage List at the security (not issuer) level. This restriction includes securities convertible into, options on, and derivatives of, such securities.

Embedded Research Analysts-should the analyst have access to place an order within a fund they will be subject to the same blackout period as a Portfolio Manager (see above).

Rules Applicable to Trading Personnel:

3 Day Blackout Period: Traders are not permitted to transact in any security that is purchased or sold in a client account 3 calendar days after the client transaction. This means a Trader must wait until calendar day 4 to trade the security. Application of this rule may be adjusted based on team function and location.

Rules applicable to Ameriprise Shares:

All employees at band level 50 and above are subject to a blackout period of trading Ameriprise shares. The blackout occurs on the first calendar day of January, April, July, and October and lasts until one full trading day after the Ameriprise earnings for the preceding quarter are publicly released. During this period employees are restricted from trading any Ameriprise shares. All applicable employees will receive emails notifying of the start and end date of the blackout.

This document is current as of the last review date but subject to change thereafter.

Columbia Threadneedle Investments (Columbia Threadneedle) is the global brand name of the Columbia and Threadneedle group of companies.

1.3. Reporting Requirements

Initial Holdings Report and Certification: Upon becoming a Covered Person under this Policy, one must disclose all securities holdings (as indicated in Appendix E-Individual Securities Requirements) in which they have Beneficial Ownership (as defined in Appendix A-Definitions). All brokerage accounts must be disclosed.

All Covered Persons are notified of this requirement and are provided with a copy of this Policy when they first become subject to the Policy. This initial certification must be completed within 10 calendar days of becoming a Covered Person. This information must be current as of the date no more than 45 days prior to the date the person becomes a Covered Person.

Annual Certification: Covered Persons are also required to complete an annual accounts and holdings certification. This certification allows the Covered Person to validate the Brokerage Accounts and certain securities holdings in which they have Beneficial Ownership (as defined in Appendix A-Definitions). Covered Persons also certify that they have received, read and understand the Policy. This information must be current as of a date no more than 45 days prior to the date the report was submitted.

Quarterly Certification: On a quarterly basis, Covered Persons must also certify to securities transactions outside of a previously reported and approved Brokerage Account. The quarterly certification must be completed within 30 calendar days of the last day of the quarter.

1.4. Confidentiality

All reports and other documents and information supplied by or on behalf of any Covered Person in accordance with the requirements of this Policy will be treated as confidential, but are subject to review as provided herein and in the procedures by Legal, Compliance and other involved departments of the Firms, by Personal Trading, senior management, by representatives relevant regulatory authority of the asset management business’ regulatory or self-regulatory authority, or otherwise as required by law, regulation, or court order.

1.5. Personal Data

The collection and use of personal data for employees and clients located in EMEA by firms is subject to regulation to ensure the protection of data subjects; the firm sets out the general principles for handling personal data that must be followed by all staff within the EMEA Personal Data Policy. The firm has put in place comprehensive but proportionate governance measures to minimise the risk of breaches and uphold the protection of personal data. The relevant measures have been documented within this Policy.

This document is current as of the last review date but subject to change thereafter.

Columbia Threadneedle Investments (Columbia Threadneedle) is the global brand name of the Columbia and Threadneedle group of companies.

2. ADMINISTRATIVE REQUIREMENTS

2.1. Summary of Legal and Regulatory Requirements

Regulatory rules require registered investment advisers and investment companies to adopt a code of ethics to; protect the firm’s clients, set forth standards of conduct, comply with applicable federal securities laws and address personal trading. SEC Rule 204A-1 under the Advisers Act (“Rule 204A-1”) requires each registered investment adviser to adopt a code of ethics that sets out standards of conduct expected of advisory personnel, safeguards material nonpublic information about client transactions and requires advisers’ “access persons” to report their personal securities transactions, including transactions in any mutual fund managed by the adviser.

Rule 17j-1 makes it unlawful for any affiliated person of a fund or any affiliated person of its investment adviser or principal underwriter to engage in certain enumerated types of misconduct in connection with the purchase or sale by such person of a security held or to be acquired by the fund. Each fund and its investment adviser and principal underwriter are required to adopt a written code of ethics containing provisions reasonably necessary to prevent the specified types of misconduct, and to use reasonable diligence and institute procedures reasonably necessary to prevent violations of the code.

FCA Rule COBS 11.7 requires a firm that conducts designated investment business to establish, implement and maintain adequate arrangements aimed at preventing certain activities (entering into certain personal transactions or advising anyone else to do so, or disclosing any non-public information) of any relevant person that may give rise to a conflict of interest, or who has access to inside information as defined in the Market Abuse Regulation3 or to other confidential information relating to clients or transactions with or for clients by virtue of an activity carried out by him on behalf of the firm.

MAS Guidelines on Risk Management Practices – Internal Controls state that an institution should have adequate policies, procedures and controls to address conflict of interest situations. It should require employees to disclose such conflicts on a timely basis. These cases should be escalated to either the Board or senior management and disclosed to customers where relevant.

MAS Guidelines on Individual Accountability and Conduct – the Board and senior management should ensure that a framework is in place to address the standards of conduct expected of all employees. This includes fair dealing (treating customers fairly) and management of conflicts of interest.

Code of Conduct for Persons licensed by or registered with the Securities and Futures Commission – A licensed person should have a policy which has been communicated to employees in writing on whether employees are permitted to deal or trade for their own accounts. Transactions of employees’ accounts and related accounts should be reported to and actively monitored and procedures maintained to detect irregularities and ensure that the handling by the licensed or registered person of these transactions or orders is not prejudicial to the interests of their clients.

This document is current as of the last review date but subject to change thereafter.

Columbia Threadneedle Investments (Columbia Threadneedle) is the global brand name of the Columbia and Threadneedle group of companies.

2.2. Roles and Responsibilities/Supervision

At least annually, each Chief Compliance Officer/Compliance Executive of the Ameriprise Global Asset Management Entities must review the adequacy of this Policy and the policies and procedures herein referenced.

2.3. Escalation for Non-Compliance

The Firms have various resources for Covered Persons to raise compliance issues and concerns on a confidential basis (refer to Appendix D-Resources for a list of Compliance resources). In general, a Covered Person should first discuss a compliance issue with their supervisor, department head, Chief Compliance Officer, Compliance Executive, or other resource listed on Appendix D-Resources. In the event that a Covered Person does not feel comfortable discussing compliance issues through these channels, the employee may anonymously report suspected violations of law or company policy by contacting their local resources (refer to Appendix D-Resources). Employees are encouraged to report these questionable practices so that the Firms have an opportunity to address and resolve these issues before they become more significant regulatory or legal issues.

Violations/Breaches of this Policy are taken seriously and may result in disciplinary actions and/or sanctions. Disciplinary actions could be up to and including termination of employment and sanctions will vary depending on local requirements or the circumstances (e.g., depending on the severity of the violation, if a record of previous violations exists, etc.).

2.4. Monitoring/Oversight

Compliance is responsible for the daily monitoring of employee personal trading and applicable accounts through the usage of personal trading assistant.

Escalation of matters are provided to appropriate local governance committee.

2.5. Disclosure

Columbia Threadneedle must provide information that is material about it’s business practices to clients and/or regulatory agencies, including information about any conflicts of interests and the policies to address such conflicts. Practices related to this Policy are publicly disclosed in accordance to local rules and regulations.

2.6. Recordkeeping

Each respective Compliance group is primarily responsible for maintaining records created with respect to this Policy and the procedures adopted to implement it. All records must be maintained for five years after the end of the fiscal year in which the documents were later of creation or last use, the first two years in an easily accessible place.

This document is current as of the last review date but subject to change thereafter.

Columbia Threadneedle Investments (Columbia Threadneedle) is the global brand name of the Columbia and Threadneedle group of companies.

APPENDIX A-DEFINITIONS

Beneficial Owner of an account or a security includes any person who, directly or indirectly, has or shares voting or investment power. For the purposes of the Code of Ethics, a beneficial owner includes accounts held in the name of you, your spouse/partner and/or any financially dependent members of your household.)

In addition, you also have Beneficial Ownership if any of the individuals listed above:

• Is a trustee or custodian for an account (e.g., for a child or parent)

• Exercises discretion over an account via a power of attorney arrangement or as an executor of an estate after death

• Has another arrangement where they give advice and also have a direct or indirect ownership (e.g., treasurer of an outside organization).

Brokerage Account: A Brokerage Account is an account held at a licensed brokerage firm in which securities on the Securities Reporting List are bought and sold (e.g., stocks, bonds, futures, options, Covered Funds). This includes employer-sponsored incentive savings plans.

Closed-End Funds: A closed-end fund is a publicly traded investment company that raises a fixed amount of capital through an (IPO. The fund is then structured, listed and traded like a stock on a stock exchange.

Covered Funds: Closed-End Funds, ETFs and Open-Ended Funds for which a Columbia Threadneedle entity serves as an investment adviser or for which an affiliate of Columbia Management Investment Advisers, LLC serves as principal underwriter are considered “Covered Funds.”

Covered Persons includes all Columbia Threadneedle employees and contractors, any other individual with a specific role (including working on a project) which compels Covered Person status due to access to proprietary information (e.g., holdings/transactions), such as the member of a staff group that provides ongoing audit, technology, finance, compliance, or legal support to Firms, and any other persons that may be deemed appropriate by Compliance.

Private Funds: Private investment funds sponsored and managed by CMIA or other entities listed in Appendix B.

Reportable Security “Reportable Security” includes all corporate securities, options on securities, warrants, rights, ETFs and municipal securities.

“Reportable Security” excludes: direct obligations of the United States government; bankers’ acceptances, bank certificates of deposit, commercial paper and high quality short-term debt instruments, including repurchase agreements; insurance company general accounts (short-term cash equivalent options of a variable life insurance policy); shares of a money market fund or other short-term income or short-term bond funds; shares of any open-end mutual fund, including any shares of a Reportable Fund; and futures and options on futures.

This document is current as of the last review date but subject to change thereafter.

Columbia Threadneedle Investments (Columbia Threadneedle) is the global brand name of the Columbia and Threadneedle group of companies.

APPENDIX B-ENTITIIES THAT HAVE ADOPTED POLICY

Ameriprise Certificate Company (ACC)

Columbia Cent CLO Advisers, LLC (CCCA)

Columbia Management Investment Advisers, LLC (CMIA)

Columbia Management Investment Distributors, Inc. (CMID)

Columbia Management Investment Services, Corp.(CMIS)

Columbia Wanger Asset Management, LLC (CWAM)

Lionstone Partners, LLC (Lionstone)

The Threadneedle group of companies*

* The Threadneedle group of companies comprises those companies whose holding company is TAM UK International Holdings Limited and Ameriprise Asset Management Holdings Singapore (PTE.) Limited.

This document is current as of the last review date but subject to change thereafter.

Columbia Threadneedle Investments (Columbia Threadneedle) is the global brand name of the Columbia and Threadneedle group of companies.

APPENDIX C – OTHER POLICIES APPLICABLE TO COVERED PERSONS

Ameriprise Financial Global Code of Conduct

Ameriprise Handling Whistleblower Claims Policy

Ameriprise Limited Choice Policy

CTI NA Policy - Privacy and Information Security and Identity Theft Prevention Program

Global Policy – Inside Information

Global Policy - Portfolio Holdings Disclosure Policy

Global Policy - Gifts and Entertainment

Global Policy – Political Contributions

Global Policy – Outside Activities and Family Relationships

Threadneedle Other Conflicts of Interest Policies Applicable to Covered Persons:

Threadneedle Market Abuse & Insider Dealing Policy

Threadneedle Conflicts of Interest Policy

Threadneedle Treating Customers Fairly

Threadneedle Whistleblowing Policy

This document is current as of the last review date but subject to change thereafter.

Columbia Threadneedle Investments (Columbia Threadneedle) is the global brand name of the Columbia and Threadneedle group of companies.

APPENDIX D –RESOURCES

Compliance Resources

Send email to Personal.Trading@ampf.com or call Personal Trading - 612-671-5196

Contact the Compliance Team if you are ever at doubt as to your obligations under this Policy.

Whistleblowing

Ameriprise Financial provides a dedicated resource through NAVEX Global (formerly known as Ethicspoint) (800-963-6395), a comprehensive and confidential reporting service for U.S. employees to report suspected fraud, abuse or other misconduct.

EMEA employees, in accordance with the EMEA/APAC Whistleblowing Policy, may contact the following for reporting, investigating and remedying any wrongdoing in the workplace.

Reporting Option	Contact Email	Contact Number (+44)
Safecall		0800 915 1571
FCA whistleblowing line	whistle@fca.gov.uk	020 7066 9200
Protect	https://protect-advice.org.uk/advice-line/p	020 3117 2520

APAC employees, in accordance with the EMEA/APAC Whistleblowing Policy, may contact the Head of HR APAC, the Head of Legal or Compliance or Safecall (number noted above) for reporting, investigating and remedying any wrongdoing in the workplace.

This document is current as of the last review date but subject to change thereafter.

Columbia Threadneedle Investments (Columbia Threadneedle) is the global brand name of the Columbia and Threadneedle group of companies.

APPENDIX E-INDIVIDUAL SECURITIES REQUIREMENTS

Pre-clearance Requirements

All securities held in brokerage accounts (including 401K Alight Financial self-directed brokerage accounts) are subject to prior approval (“pre-clearance”) under the Policy, including ETFs, Closed End Funds and publicly traded crypto-related securities, except those listed below:

• Ameriprise Financial Stock⁴ (only)

• Annuities and Life Insurance (where there is no specific investment exposure)

• Bank products (checking/savings, CDs, etc.)

• Currencies

• Digital assets/cryptocurrencies

• Debt securities issued by any government

• Dividend Reinvestment Plans (DRIPS)

• Futures

• Money Market Funds

• Non-Investment derivatives – sporting bets only

• Open-End Mutual Funds

• Columbia Threadneedle - EMEA Products*

• Unit Investment Trusts (UITs)

* Pre-clearance only required by FPDC/SPC members (applicable to EMEA only).

Reporting Requirements

Brokerage accounts

All brokerage accounts, including the Alight 401(k) self-directed accounts, must be reported to Personal Trade Compliance through the PTA system. This reporting requirement applies even if the holdings in the account do not require reporting (See Holdings below).

Holdings

The following securities do not require reporting:

• Ameriprise Financial Stock

• Annuities (report only Covered Funds listed in Appendix F)

• Bank products (checking/savings, CDs etc.)

• Currencies

• Debt securities issued by any government

• 529 plans

• Money Market Funds

• Open-End Mutual Funds (report only Covered Funds listed in Appendix F)

⁴  Other rules, including blackout and holding periods, still apply and there can be no speculative trading in Ameriprise Financial Stock.

This document is current as of the last review date but subject to change thereafter.

Columbia Threadneedle Investments (Columbia Threadneedle) is the global brand name of the Columbia and Threadneedle group of companies.

APPENDIX F-COVERED FUNDS LIST

The Global Asset Management Personal Account Dealing and Code of Ethics Policy (“Policy”) speaks to certain rules concerning activity within Covered Funds. Closed-End Funds, ETFs and Mutual Funds for which Columbia Management Investment Advisers, LLC serves as an investment adviser or for which an affiliate of Columbia Management Investment Advisers, LLC serves as principal underwriter are considered “Covered Funds.” ⁵

The following is the list of Covered Funds as of December 2021:

• All Columbia Mutual Funds (both retail and variable), including Columbia Acorn Funds, Wanger Funds, and Multi-Manager Funds offered through Ameriprise Financial advisory programs

• All Columbia ETFs

• All Columbia Threadneedle – EMEA and Asia Funds

• Columbia Seligman Premium Technology Growth Fund, Inc.

• Tri-Continental Corporation

• BMO Disciplined International Fund, Mid-Cap Value Fund, Small-Cap Value Fund, Mid-Cap Growth Fund, Dividend Income Fund, Large Cap Value Fund, Low Volatility Equity Fund, Large Cap Growth Fund, Small-Cap Growth Fund

Third-Party Funds Sub Advised by CMIA:

• Destinations Large Cap Equity Fund

• NVIT Columbia Overseas Value Fund

• Pathway Large Cap Equity Fund

• SA Columbia Focused Value Portfolio

• VALIC Company I Capital Appreciation Fund

• VY Columbia Contrarian Core Portfolio

• VY Columbia Small Cap Value II Portfolio

⁵  Under the Volcker Rule, certain employee investments/holdings in proprietary funds may need to be reviewed to ensure that the holdings meet banking exclusions and exemptions requirements. Employees identified as “senior executive officers or directors” may need to provide holdings data for these funds on an ad hoc basis for analysis by the GCO.

This document is current as of the last review date but subject to change thereafter.

Columbia Threadneedle Investments (Columbia Threadneedle) is the global brand name of the Columbia and Threadneedle group of companies.

APPENDIX G-OPTIONS/SHORT TRADING GUIDELINES

Short Trading-General Guidelines

Shorting individual securities is prohibited. Shorting broad-based market securities (ETFs) is permitted.

Options Trading-General Guidelines

All persons subject to the Policy should not deal in any form of derivative that could give rise to an open ended, unlimited liability.

All Covered Persons must obtain pre-clearance via PTA prior to placing an options trade.

Short term trading at a profit is prohibited under the code. Covered Persons may not trade options that will result in a gain if held less than 30 days. Covered Persons must wait trade date plus 30 days before closing the position at a profit.    

Acceptable Transactions

• Options that have an expiration greater than 30 days and

• Out of the money option contracts

• In the money option contracts only if there is an underlying position held greater than 30 days

Prohibited Transactions

• Options that have an expiration within 30 days

• In the money option contracts – unless there is a sufficient underlying position held greater than 30 days (100 shares per contract)

• Buying and selling options contracts at a profit held less than 30 days

Key Reminders

Covered Persons are required to preclear the option ticker symbol (please use the new option symbology) and not the underlying ticker.

Covered Persons are responsible for calculating the 30-day holding period (Trade date + 30 days), you must use the average cost method (PTA does not calculate the 30-day holding period).

Receiving pre-clearance does not exclude you from other personal trading rules included in the Policy.

This document is current as of the last review date but subject to change thereafter.

Columbia Threadneedle Investments (Columbia Threadneedle) is the global brand name of the Columbia and Threadneedle group of companies.

APPENDIX H-LIMITED CHOICE POLICY

In order to comply with regulators expectations concerning the monitoring of trading activity within Covered Person accounts, Ameriprise Financial and Columbia Threadneedle Investments maintain a “limited choice” brokerage policy which dictates where certain types of securities must be held and traded.

The types of securities that are subject to the Limited Choice Policy are specified in Appendix E-Individual Securities Requirements. Securities not subject to the Limited Choice Policy may be held in brokerage accounts and must meet certain requirements. See Notification of Brokerage Accounts in Section 1.2 of Policy.

Securities subject to the Limited Choice Policy must be held, and trading must be conducted, through one of these brokers. Due to global availability of certain brokers and electronic feeds from those brokers, each region has specific requirements that must be followed for that region:

• Ameriprise/Columbia Threadneedle North America - Ameriprise Financial Brokerage, Charles Schwab, Merrill Lynch

• Columbia Threadneedle UK – Barclays, Hargreaves Lansdown, Interactive Brokers (Charles Schwab and Merrill Lynch – restricted to U.S based accounts only)

• Columbia Threadneedle EMEA, excluding UK -. Employees of Columbia Threadneedle EMEA must report their broker accounts on PTA prior to trading and provide contract notes to Personal Trade Compliance as soon as practicable following execution of their trade.

• Columbia Threadneedle APAC—Singapore employees are encouraged to use UOB and Interactive because they do provide electronic feeds. Employees of Columbia Threadneedle APAC must report their broker accounts on PTA prior to trading and provide contract notes (if not on an electronic feed) to Personal Trade Compliance as soon as practicable following execution of their trade.

If you maintain a brokerage account outside of the approved brokers that holds securities subject to the Limited Choice policy, you have the following options:

1. You may transfer the subject holdings to a like-ownership account at one of the approved brokers for your region. See Notification of Brokerage Accounts in Section 1.2 of Policy.

2. You may liquidate the subject holdings (subject to the requirements in the Policy) and either hold the proceeds as cash or reinvest in non-subject securities.

3. You may apply for an exception. Contact Personal Trading for more information about what may be an allowable exception and what steps need to be taken to request an exception. An exception does not make you exempt from complying with all other requirements in Policy).

Covered Persons must comply with the Limited Choice Policy requirements within 30 days of becoming a Covered Person.

This document is current as of the last review date but subject to change thereafter.

Columbia Threadneedle Investments (Columbia Threadneedle) is the global brand name of the Columbia and Threadneedle group of companies.

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Fees and Expenses of the Fund

Expense Narrative [Text Block]

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This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below. You may qualify for sales charge discounts if you and members of your immediate family invest, or agree to invest in the future, at least $50,000 in certain classes of shares of eligible funds distributed by Columbia Management Investment Distributors, Inc. (the Distributor). More information is available about these and other sales charge discounts and waivers from your financial intermediary, and can be found in the Choosing a Share Class section beginning on page 28 of the Fund’s prospectus, in Appendix A to the prospectus beginning on page A-1 and in Appendix S to the Statement of Additional Information (SAI) under Sales Charge Waivers beginning on page S-1.

Shareholder Fees Caption [Text]

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Shareholder Fees (fees paid directly from your investment)

Operating Expenses Caption [Text]

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Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

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April 30, 2023

Portfolio Turnover [Heading]

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Portfolio Turnover

Portfolio Turnover [Text Block]

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The Fund may pay transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 21% of the average value of its portfolio.

Portfolio Turnover, Rate

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21.00%

Expense Breakpoint Discounts [Text]

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You may qualify for sales charge discounts if you and members of your immediate family invest, or agree to invest in the future, at least $50,000 in certain classes of shares of eligible funds distributed by Columbia Management Investment Distributors, Inc. (the Distributor). More information is available about these and other sales charge discounts and waivers from your financial intermediary, and can be found in the Choosing a Share Class section beginning on page 28 of the Fund’s prospectus, in Appendix A to the prospectus beginning on page A-1 and in Appendix S to the Statement of Additional Information (SAI) under Sales Charge Waivers beginning on page S-1.

Expense Breakpoint, Minimum Investment Required [Amount]

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$ 50,000

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

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“Total annual Fund operating expenses” include acquired fund fees and expenses (expenses the Fund incurs indirectly through its investments in other investment companies) and may be higher than the ratio of expenses to average net assets shown in the Financial Highlights section of this prospectus because the ratio of expenses to average net assets does not include acquired fund fees and expenses.

Expense Example [Heading]

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 Example

Expense Example Narrative [Text Block]

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The following example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example illustrates the hypothetical expenses that you would incur over the time periods indicated, and assumes that:

■ you invest $10,000 in the applicable class of Fund shares for the periods indicated,

■ your investment has a 5% return each year, and

■ the Fund’s total annual operating expenses remain the same as shown in the Annual Fund Operating Expenses table above.

Since the waivers and/or reimbursements shown in the Annual Fund Operating Expenses table above expire as indicated in the preceding table, they are only reflected in the 1 year example and the first year of the other examples. Although your actual costs may be higher or lower, based on the assumptions listed above, your costs would be:

Strategy [Heading]

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Principal Investment Strategies

Strategy Narrative [Text Block]

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Under normal circumstances, the Fund invests at least 80% of its net assets (plus any borrowing for investment purposes) in European companies. Under normal circumstances, the Fund invests at least 70% of its total assets in companies in Western European countries (for example, the United Kingdom, Germany, France and Italy), but also may invest up to 30% of its total assets in companies in emerging Central and Eastern European countries (for example, Poland, the Czech Republic, Turkey and Cyprus). For purposes of the Fund's policies, the Fund may invest in a company if (i) it is domiciled in, or the principal trading market for its securities is in, a European country, (ii) it derives 50% or more of its economic value from goods produced, sales made or services performed or has at least 50% of its assets in a European country or countries or (iii) it is a holding company that predominantly holds shares in such companies. The Fund may invest in a variety of countries, industries and sectors and does not attempt to invest a specific percentage of its assets in any given country, industry or sector.

Under normal circumstances, the Fund invests a majority of its net assets in the common stock of small- and mid-sized companies with market capitalizations generally in the range of market capitalizations in the MSCI AC Europe Small Cap Index (Net), the Fund's benchmark, (the Index) at the time of purchase (between $85.4 million and $10.6 billion as of March 31, 2022). The market capitalization range and composition of companies in the Index are subject to change. As such, the size of the companies in which the Fund invests may change. The Fund determines a company’s market capitalization at the time of investment. As long as a majority of its net assets are invested in companies within the Index, the Fund may continue to hold and make new investments in a security even if the 

company’s market capitalization grows beyond the market capitalization of the largest company within the Index or falls below the market capitalization of the smallest company within the Index. The Investment Manager from time to time emphasizes one or more sectors in selecting the Fund’s investments, including the industrials, information technology, and health care sectors. 

Columbia Wanger Asset Management, LLC, the Fund's investment adviser (the Investment Manager), believes that stocks of small- and mid-sized companies, which generally are not as well known by financial analysts as larger companies, may offer higher return potential than stocks of larger companies. 

The Fund takes advantage of the Investment Manager's research and stock-picking capabilities to initially invest in a limited number of companies (generally under 100), offering the potential to provide above-average growth over time. 

The Investment Manager typically seeks companies with: 

■ A strong business franchise that offers growth potential. 

■ Products and services in which the company has a competitive advantage. 

■ A stock price the Investment Manager believes is reasonable relative to the assets and earning power of the company. 

The Investment Manager may sell a portfolio holding if the security reaches the Investment Manager's price target, if the company has a deterioration of fundamentals, such as failing to meet key operating benchmarks, or if the Investment Manager believes other securities are more attractive. The Investment Manager also may sell a portfolio holding to fund redemptions. 

Risk [Heading]

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Principal Risks

Risk Narrative [Text Block]

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An investment in the Fund involves risks, including those described below, among others. There is no assurance that the Fund will achieve its investment objective and you may lose money. The value of the Fund’s holdings may decline, and the Fund’s net asset value (NAV) and share price may go down. An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Active Management Risk. The Investment Manager’s active management of the Fund could cause the Fund to underperform its benchmark index and/or other funds with similar investment objectives and/or strategies.

Market Risk. The Fund may incur losses due to declines in the value of one or more securities in which it invests. These declines may be due to factors affecting a particular issuer, or the result of, among other things, political, regulatory, market, economic or social developments affecting the relevant market(s) more generally. In addition, turbulence in financial markets and reduced liquidity in equity, credit and/or fixed income markets may negatively affect many issuers, which could adversely affect the Fund’s ability to price or value hard-to-value assets in thinly traded and closed markets and could cause significant redemptions and operational challenges. Global economies and financial markets are increasingly interconnected, and conditions and events in one country, region or financial market may adversely impact issuers in a different country, region or financial market. These risks may be magnified if certain events or developments adversely interrupt the global supply chain; in these and other circumstances, such risks might affect companies worldwide. As a result, local, regional or global events such as terrorism, war, other conflicts, natural disasters, disease/virus outbreaks and epidemics or other public health issues, recessions, depressions or other events – or the potential for such events – could have a significant negative impact on global economic and market conditions. 

The large-scale invasion of Ukraine by Russia in February 2022 has resulted in sanctions and market disruptions including declines in regional and global stock and commodity markets and significant devaluations of Russian currency. The extent and duration of the military action are impossible to predict but could be significant. Market disruption caused by the Russian military action, and any counter measures or responses thereto (including international sanctions, a downgrade in the country’s credit rating, purchasing and financing restrictions, boycotts, tariffs, changes in consumer or purchaser preferences, cyberattacks and espionage) could have severe adverse impacts on regional and/or global securities and commodities markets, including markets for oil and natural gas. 

These impacts may include reduced market liquidity, distress in credit markets, further disruption of global supply chains, increased risk of inflation, and limited access to investments in certain international markets and/or issuers. These developments and other related events could negatively impact Fund performance. 

The pandemic caused by coronavirus disease 2019 and its variants (COVID-19) has resulted in, and may continue to result in, significant global economic and societal disruption and market volatility due to disruptions in market access, resource availability, facilities operations, imposition of tariffs, export controls and supply chain disruption, among others. Such disruptions may be caused, or exacerbated by, quarantines and travel restrictions, workforce displacement and loss in human and other resources. The uncertainty surrounding the magnitude, duration, reach, costs and effects of the global pandemic, as well as actions that have been or could be taken by governmental authorities or other third parties, present unknowns that are yet to unfold. The impacts, as well as the uncertainty over impacts to come, of COVID-19 – and any other infectious illness outbreaks, epidemics and pandemics that may arise in the future – could negatively affect global economies and markets in ways that cannot necessarily be foreseen. In addition, the impact of infectious illness outbreaks and epidemics in emerging market countries may be greater due to generally less established healthcare systems, governments and financial markets. Public health crises caused by the COVID-19 outbreak may exacerbate other pre-existing political, social and economic risks in certain countries or globally. The disruptions caused by COVID-19 could prevent the Fund from executing advantageous investment decisions in a timely manner and negatively impact the Fund’s ability to achieve its investment objective. Any such events could have a significant adverse impact on the value and risk profile of the Fund. 

Liquidity and Trading Volume Risk. Due to market conditions, including uncertainty regarding the price of a security, it may be difficult for the Fund to buy or sell portfolio securities at a desirable time or price, which could result in investment losses. This risk of portfolio illiquidity is heightened with respect to small- and mid-cap securities, generally, and foreign small- and mid-cap securities in particular. The Fund may have to lower the selling price, liquidate other investments, or forego another, more appealing investment opportunity as a result of illiquidity in the markets. The Fund may also be limited in its ability to execute favorable trades in portfolio securities in response to changes in share prices and fundamentals, and may be forced to dispose of securities under disadvantageous circumstances and at a loss. As the Fund grows in size or, conversely, if it faces significant redemption pressure, these considerations take on increasing significance and may adversely impact performance. 

Small- and Mid-Cap Company Securities Risk. Investments in small- and mid-cap companies often involve greater risks than investments in larger, more established companies because small- and mid-cap companies tend to have less predictable earnings and may lack the management experience, financial resources, product diversification and competitive strengths of larger companies. Securities of small- and mid-cap companies may be less liquid and more volatile than the securities of larger companies. 

Sector Risk. At times, the Fund may have a significant portion of its assets invested in securities of companies conducting business within one or more economic sectors, including the industrials, information technology, and health care sectors. Companies in the same sector may be similarly affected by economic, regulatory, political or market events or conditions, which may make the Fund more vulnerable to unfavorable developments in that sector than funds that invest more broadly. Generally, the more broadly the Fund invests, the more it spreads risk and potentially reduces the risks of loss and volatility. 

■ Industrials Sector. The Fund is more susceptible to the particular risks that may affect companies in the industrials sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the industrials sector are subject to certain risks, including changes in supply and demand for their specific product or service and for industrial sector products in general, including decline in demand for such products due to rapid technological developments and frequent new product introduction. Performance of such companies may be affected by factors including government regulation, world events, economic conditions and risks for environmental damage and product liability claims. 

■ Information Technology Sector. The Fund is more susceptible to the particular risks that may affect companies in the information technology sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the information technology sector are subject to certain risks, including the risk that new services, 

equipment or technologies will not be accepted by consumers and businesses or will become rapidly obsolete. Performance of such companies may be affected by factors including obtaining and protecting patents (or the failure to do so) and significant competitive pressures, including aggressive pricing of their products or services, new market entrants, competition for market share and short product cycles due to an accelerated rate of technological developments. Such competitive pressures may lead to limited earnings and/or falling profit margins. As a result, the value of their securities may fall or fail to rise. In addition, many information technology sector companies have limited operating histories and prices of these companies’ securities historically have been more volatile than other securities, especially over the short term. Some companies in the information technology sector are facing increased government and regulatory scrutiny and may be subject to adverse government or regulatory action, which could negatively impact the value of their securities. 

■ Health Care Sector. The Fund is more susceptible to the particular risks that may affect companies in the health care sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the health care sector are subject to certain risks, including restrictions on government reimbursement for medical expenses, government approval of medical products and services, competitive pricing pressures, and the rising cost of medical products and services (especially for companies dependent upon a relatively limited number of products or services), among others. Performance of such companies may be affected by factors including, government regulation, obtaining and protecting patents (or the failure to do so), product liability and other similar litigation as well as product obsolescence. 

Foreign Securities Risk. Investments in or exposure to securities of foreign companies may involve heightened risks relative to investments in or exposure to securities of U.S. companies. Investing in securities of foreign companies subjects the Fund to the risks associated with an issuer’s (and any of its related companies’) country of organization and places of business operations, including risks related to political, regulatory, economic, social, diplomatic and other conditions or events (including, for example, military confrontations and actions, war, other conflicts, terrorism and disease/virus outbreaks and epidemics) occurring in the country or region, as well as risks associated with less developed custody and settlement practices. Foreign securities may be more volatile and less liquid than securities of U.S. companies, and are subject to the risks associated with potential imposition of economic and other sanctions against a particular foreign country, its nationals or industries or businesses within the country. In addition, foreign governments may impose withholding or other taxes on the Fund’s income, capital gains or proceeds from the disposition of foreign securities, which could reduce the Fund’s return on such securities. 

Operational and Settlement Risks of Foreign Securities. The Fund’s foreign securities are generally held outside the United States in the primary market for the securities in the custody of foreign sub-custodians. Some countries have limited governmental oversight and regulation, which increases the risk of corruption and fraud and the possibility of losses to the Fund. In particular, under certain circumstances, foreign securities may settle on a delayed delivery basis, meaning that the Fund may be required to make payment for securities before the Fund has actually received delivery of the securities or deliver securities prior to the receipt of payment. As a result, there is a risk that the security will not be delivered to the Fund or that payment will not be received. Losses can also result from lost, stolen or counterfeit securities; defaults by brokers and banks; failures or defects of the settlement system; or poor and improper record keeping by registrars and issuers. 

Share Blocking. In certain non-U.S. markets, an issuer’s securities are blocked from trading for a specified number of days before and, in certain instances, after a shareholder meeting. The blocking period can last up to several weeks. Share blocking may prevent the Fund from buying or selling securities during this period. As a consequence of these restrictions, the Investment Manager, on behalf of the Fund, may abstain from voting proxies in markets that require share blocking. 

Geographic Focus Risk. The Fund may be particularly susceptible to risks related to economic, political, regulatory or other events or conditions affecting issuers and countries within the specific geographic regions in which the Fund invests. The Fund’s NAV may be more volatile than the NAV of a more geographically diversified fund. 

■ Europe. The Fund is particularly susceptible to risks related to economic, political, regulatory or other events or conditions, including acts of war or other conflicts in the region, affecting issuers and countries in Europe. Countries in Europe are often closely connected and interdependent, and events in one European country can have 

an adverse impact on, and potentially spread to, other European countries. In addition, significant private and public sectors’ debt problems of a single European Union (EU) country can pose economic risks to the EU as a whole. As a result, the Fund’s NAV may be more volatile than the NAV of a more geographically diversified fund. If securities of issuers in Europe fall out of favor, it may cause the Fund to underperform other funds that do not focus their investments in this region of the world. The departure of the United Kingdom (UK) from the EU single market became effective January 1, 2021 with the end of the Brexit transition period and the post-Brexit trade deal between the UK and EU taking effect on December 31, 2020. The impact of any partial or complete dissolution of the EU on the UK and European economies and the broader global economy could be significant, resulting in negative impacts on currency and financial markets generally, such as increased volatility and illiquidity, and potentially lower economic growth in markets in Europe, which may adversely affect the value of your investment in the Fund. 

Emerging Market Securities Risk. Securities issued by foreign governments or companies in emerging market countries are more likely to have greater exposure to the risks of investing in foreign securities that are described in Foreign Securities Risk. In addition, emerging market countries are more likely to experience instability resulting, for example, from rapid changes or developments in social, political, economic or other conditions. Their economies are usually less mature and their securities markets are typically less developed with more limited trading activity (i.e., lower trading volumes and less liquidity) than more developed countries. Emerging market securities tend to be more volatile, and may be more susceptible to market manipulation, than securities in more developed markets. Many emerging market countries are heavily dependent on international trade and have fewer trading partners, which makes them more sensitive to world commodity prices and economic downturns in other countries, and some have a higher risk of currency devaluations. Due to the differences in the nature and quality of financial information of issuers of emerging market securities, including auditing and financial reporting standards, financial information and disclosures about such issuers may be unavailable or, if made available, may be considerably less reliable than publicly available information about other foreign securities. 

Operational and Settlement Risks of Securities in Emerging Markets. Foreign sub-custodians in emerging markets may be recently organized, lack extensive operating experience or lack effective government oversight or regulation. In addition, there may be legal restrictions or limitations on the ability of the Fund to recover assets held in custody by a foreign sub-custodian in the event of the bankruptcy of the sub-custodian. There may also be a greater risk that settlement may be delayed and that cash or securities of the Fund may be lost because of failures of or defects in the system, including fraud or corruption. Settlement systems in emerging markets also have a higher risk of failed trades. 

Risks Related to Currencies and Corporate Actions in Emerging Markets. Risks related to currencies and corporate actions are also greater in emerging market countries than in developed countries. Emerging market currencies may not have an active trading market and are subject to a higher risk of currency devaluations. 

Risks Related to Corporate and Securities Laws in Emerging Markets. Securities laws in emerging markets may be relatively new and unsettled and, consequently, there is a risk of rapid and unpredictable change in laws regarding foreign investment, securities regulation, title to securities and shareholder rights. 

Foreign Currency Risk. The performance of the Fund may be materially affected positively or negatively by foreign currency strength or weakness relative to the U.S. dollar, particularly if the Fund invests a significant percentage of its assets in foreign securities or other assets denominated in currencies other than the U.S. dollar. 

Issuer Risk. An issuer in which the Fund invests may perform poorly, and the value of its securities may therefore decline, which may negatively affect the Fund’s performance. Underperformance of an issuer may be caused by poor management decisions, competitive pressures, breakthroughs in technology, reliance on suppliers, labor problems or shortages, corporate restructurings, fraudulent disclosures, natural disasters, military confrontations and actions, war, terrorism, disease/virus outbreaks and epidemics or other events, conditions and factors. 

Growth Securities Risk. Growth securities typically trade at a higher multiple of earnings than other types of equity securities. Accordingly, the market values of growth securities may never reach their expected market value and may decline in price. In addition, growth securities, at times, may not perform as well as value securities or the stock market in general, and may be out of favor with investors for varying periods of time. 

Risk Lose Money [Text]

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There is no assurance that the Fund will achieve its investment objective and you may lose money.

Risk Not Insured Depository Institution [Text]

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An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Bar Chart and Performance Table [Heading]

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Performance Information

Performance Narrative [Text Block]

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The following bar chart and table show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. The bar chart shows how the Fund’s Class Inst share performance has varied for each full calendar year shown. The table below the bar chart compares the Fund’s returns for the periods shown with the MSCI AC Europe Small Cap Index (Net). The MSCI AC Europe Small Cap Index (Net) captures small-cap representation across 20 countries in Europe.  It has 1,130 constituents and covers approximately 14% of the free float-adjusted market capitalization across each country in Europe (as of March 31, 2022).

The performance of one or more share classes shown in the Average Annual Total Returns table below includes the Fund’s Class Inst share returns (adjusted to reflect the higher class-related operating expenses of such classes, where applicable) for periods prior to the indicated inception date of such share classes. Except for differences in fees and expenses, all share classes of the Fund would have substantially similar annual returns because all share classes of the Fund invest in the same portfolio of securities. 

The after-tax returns shown in the Average Annual Total Returns table below are calculated using the highest historical individual U.S. federal marginal income tax rates in effect during the period indicated in the table and do not reflect the impact of state, local or foreign taxes. Your actual after-tax returns will depend on your personal tax situation and may differ from those shown in the table. In addition, the after-tax returns shown in the table do not apply to shares held in tax-advantaged accounts such as 401(k) plans or Individual Retirement Accounts (IRAs). The after-tax returns are shown only for Class Inst shares and will vary for other share classes. 

The Fund’s past performance (before and after taxes) is no guarantee of how the Fund will perform in the future. Updated performance information can be obtained by calling toll-free 800.345.6611 or visiting columbiathreadneedleus.com. 

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following bar chart and table show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. The bar chart shows how the Fund’s Class Inst share performance has varied for each full calendar year shown. The table below the bar chart compares the Fund’s returns for the periods shown with the MSCI AC Europe Small Cap Index (Net). The MSCI AC Europe Small Cap Index (Net) captures small-cap representation across 20 countries in Europe.  It has 1,130 constituents and covers approximately 14% of the free float-adjusted market capitalization across each country in Europe (as of March 31, 2022).

Performance Availability Phone [Text]

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800.345.6611

Performance Availability Website Address [Text]

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columbiathreadneedleus.com

Performance Past Does Not Indicate Future [Text]

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The Fund’s past performance (before and after taxes) is no guarantee of how the Fund will perform in the future.

Bar Chart [Heading]

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Year by Year Total Return (%) as of December 31 Each Year*

Bar Chart Closing [Text Block]

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Best and Worst Quarterly Returns During the Period Shown in the Bar Chart Best 2nd Quarter 2020 30.55% Worst 1st Quarter 2020 -28.33%

Performance Table Heading

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 Average Annual Total Returns After Applicable Sales Charges (for periods ended December 31, 2021)

Performance Table Uses Highest Federal Rate

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The after-tax returns shown in the Average Annual Total Returns table below are calculated using the highest historical individual U.S. federal marginal income tax rates in effect during the period indicated in the table and do not reflect the impact of state, local or foreign taxes.

Performance Table Not Relevant to Tax Deferred

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In addition, the after-tax returns shown in the table do not apply to shares held in tax-advantaged accounts such as 401(k) plans or Individual Retirement Accounts (IRAs).

Performance Table One Class of after Tax Shown [Text]

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The after-tax returns are shown only for Class Inst shares and will vary for other share classes.

Columbia Acorn European Fund | Class A

Risk/Return:

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Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

5.75%

Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)

rr_MaximumDeferredSalesChargeOverOther

1.00%

^[1]

Management fees

rr_ManagementFeesOverAssets

1.09%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

0.25%

Other expenses

rr_OtherExpensesOverAssets

0.29%

Total annual Fund operating expenses

rr_ExpensesOverAssets

1.63%

^[2]

Fee waivers and/or expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.18%)

^[3]

Total annual Fund operating expenses after fee waivers and/or expense reimbursements

rr_NetExpensesOverAssets

1.45%

Expenses Deferred Charges [Text Block]

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This charge is imposed on certain investments of between $1 million and $50 million redeemed within 18 months after purchase, as follows: 1.00% if redeemed within 12 months after purchase, and 0.50% if redeemed more than 12, but less than 18, months after purchase, with certain limited exceptions.

1 year

rr_ExpenseExampleYear01

$ 714

3 years

rr_ExpenseExampleYear03

1,043

5 years

rr_ExpenseExampleYear05

1,395

10 years

rr_ExpenseExampleYear10

2,382

1 year

rr_ExpenseExampleNoRedemptionYear01

714

3 years

rr_ExpenseExampleNoRedemptionYear03

1,043

5 years

rr_ExpenseExampleNoRedemptionYear05

1,395

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 2,382

1 Year

rr_AverageAnnualReturnYear01

14.47%

5 Years

rr_AverageAnnualReturnYear05

18.11%

10 Years

rr_AverageAnnualReturnYear10

13.58%

Share Class Inception Date

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Aug. 19, 2011

Columbia Acorn European Fund | Class C

Risk/Return:

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Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)

rr_MaximumDeferredSalesChargeOverOther

1.00%

^[4]

Management fees

rr_ManagementFeesOverAssets

1.09%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

1.00%

Other expenses

rr_OtherExpensesOverAssets

0.29%

Total annual Fund operating expenses

rr_ExpensesOverAssets

2.38%

^[2]

Fee waivers and/or expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.18%)

^[3]

Total annual Fund operating expenses after fee waivers and/or expense reimbursements

rr_NetExpensesOverAssets

2.20%

Expenses Deferred Charges [Text Block]

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This charge applies to redemptions within 12 months after purchase, with certain limited exceptions.

1 year

rr_ExpenseExampleYear01

$ 323

3 years

rr_ExpenseExampleYear03

725

5 years

rr_ExpenseExampleYear05

1,254

10 years

rr_ExpenseExampleYear10

2,516

1 year

rr_ExpenseExampleNoRedemptionYear01

223

3 years

rr_ExpenseExampleNoRedemptionYear03

725

5 years

rr_ExpenseExampleNoRedemptionYear05

1,254

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 2,516

1 Year

rr_AverageAnnualReturnYear01

19.57%

5 Years

rr_AverageAnnualReturnYear05

18.64%

10 Years

rr_AverageAnnualReturnYear10

13.40%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Aug. 19, 2011

Columbia Acorn European Fund | Class Inst

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)

rr_MaximumDeferredSalesChargeOverOther

none

Management fees

rr_ManagementFeesOverAssets

1.09%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.29%

Total annual Fund operating expenses

rr_ExpensesOverAssets

1.38%

^[2]

Fee waivers and/or expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.18%)

^[3]

Total annual Fund operating expenses after fee waivers and/or expense reimbursements

rr_NetExpensesOverAssets

1.20%

1 year

rr_ExpenseExampleYear01

$ 122

3 years

rr_ExpenseExampleYear03

419

5 years

rr_ExpenseExampleYear05

738

10 years

rr_ExpenseExampleYear10

1,642

1 year

rr_ExpenseExampleNoRedemptionYear01

122

3 years

rr_ExpenseExampleNoRedemptionYear03

419

5 years

rr_ExpenseExampleNoRedemptionYear05

738

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 1,642

2012

rr_AnnualReturn2012

25.66%

^[5]

2013

rr_AnnualReturn2013

33.98%

^[5]

2014

rr_AnnualReturn2014

(7.52%)

^[5]

2015

rr_AnnualReturn2015

4.43%

^[5]

2016

rr_AnnualReturn2016

(3.29%)

^[5]

2017

rr_AnnualReturn2017

38.35%

^[5]

2018

rr_AnnualReturn2018

(18.57%)

^[5]

2019

rr_AnnualReturn2019

46.35%

^[5]

2020

rr_AnnualReturn2020

23.08%

^[5]

2021

rr_AnnualReturn2021

21.76%

^[5]

Year to Date Return, Label

rr_YearToDateReturnLabel

Year to Date return

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Mar. 31, 2022

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

(21.84%)

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2020

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

30.55%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Mar. 31, 2020

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(28.33%)

1 Year

rr_AverageAnnualReturnYear01

21.76%

5 Years

rr_AverageAnnualReturnYear05

19.83%

10 Years

rr_AverageAnnualReturnYear10

14.54%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Aug. 19, 2011

Columbia Acorn European Fund | Class Inst2

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)

rr_MaximumDeferredSalesChargeOverOther

none

Management fees

rr_ManagementFeesOverAssets

1.09%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.26%

Total annual Fund operating expenses

rr_ExpensesOverAssets

1.35%

^[2]

Fee waivers and/or expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.21%)

^[3]

Total annual Fund operating expenses after fee waivers and/or expense reimbursements

rr_NetExpensesOverAssets

1.14%

1 year

rr_ExpenseExampleYear01

$ 116

3 years

rr_ExpenseExampleYear03

407

5 years

rr_ExpenseExampleYear05

719

10 years

rr_ExpenseExampleYear10

1,606

1 year

rr_ExpenseExampleNoRedemptionYear01

116

3 years

rr_ExpenseExampleNoRedemptionYear03

407

5 years

rr_ExpenseExampleNoRedemptionYear05

719

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 1,606

1 Year

rr_AverageAnnualReturnYear01

21.80%

5 Years

rr_AverageAnnualReturnYear05

19.90%

10 Years

rr_AverageAnnualReturnYear10

14.58%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Nov. 08, 2012

Columbia Acorn European Fund | Class Adv

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)

rr_MaximumDeferredSalesChargeOverOther

none

Management fees

rr_ManagementFeesOverAssets

1.09%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.29%

Total annual Fund operating expenses

rr_ExpensesOverAssets

1.38%

^[2]

Fee waivers and/or expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.18%)

^[3]

Total annual Fund operating expenses after fee waivers and/or expense reimbursements

rr_NetExpensesOverAssets

1.20%

1 year

rr_ExpenseExampleYear01

$ 122

3 years

rr_ExpenseExampleYear03

419

5 years

rr_ExpenseExampleYear05

738

10 years

rr_ExpenseExampleYear10

1,642

1 year

rr_ExpenseExampleNoRedemptionYear01

122

3 years

rr_ExpenseExampleNoRedemptionYear03

419

5 years

rr_ExpenseExampleNoRedemptionYear05

738

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 1,642

1 Year

rr_AverageAnnualReturnYear01

21.75%

5 Years

rr_AverageAnnualReturnYear05

19.83%

10 Years

rr_AverageAnnualReturnYear10

14.55%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Jun. 25, 2014

Columbia Acorn European Fund | Class Inst3

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)

rr_MaximumDeferredSalesChargeOverOther

none

Management fees

rr_ManagementFeesOverAssets

1.09%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.22%

Total annual Fund operating expenses

rr_ExpensesOverAssets

1.31%

^[2]

Fee waivers and/or expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.20%)

^[3]

Total annual Fund operating expenses after fee waivers and/or expense reimbursements

rr_NetExpensesOverAssets

1.11%

1 year

rr_ExpenseExampleYear01

$ 113

3 years

rr_ExpenseExampleYear03

395

5 years

rr_ExpenseExampleYear05

699

10 years

rr_ExpenseExampleYear10

1,562

1 year

rr_ExpenseExampleNoRedemptionYear01

113

3 years

rr_ExpenseExampleNoRedemptionYear03

395

5 years

rr_ExpenseExampleNoRedemptionYear05

699

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 1,562

1 Year

rr_AverageAnnualReturnYear01

21.83%

5 Years

rr_AverageAnnualReturnYear05

19.93%

10 Years

rr_AverageAnnualReturnYear10

14.58%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Mar. 01, 2017

Columbia Acorn European Fund | returns after taxes on distributions | Class Inst

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

21.69%

5 Years

rr_AverageAnnualReturnYear05

19.70%

10 Years

rr_AverageAnnualReturnYear10

14.42%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Aug. 19, 2011

Columbia Acorn European Fund | returns after taxes on distributions and sale of Fund shares | Class Inst

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

13.02%

5 Years

rr_AverageAnnualReturnYear05

16.25%

10 Years

rr_AverageAnnualReturnYear10

12.36%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Aug. 19, 2011

Columbia Acorn European Fund | MSCI AC Europe Small Cap Index (Net) (reflects reinvested dividends net of withholding taxes but reflects no deductions for fees, expenses or other taxes)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

14.74%

5 Years

rr_AverageAnnualReturnYear05

12.84%

10 Years

rr_AverageAnnualReturnYear10

12.67%

[1] This charge is imposed on certain investments of between $1 million and $50 million redeemed within 18 months after purchase, as follows: 1.00% if redeemed within 12 months after purchase, and 0.50% if redeemed more than 12, but less than 18, months after purchase, with certain limited exceptions.

[2] “Total annual Fund operating expenses” include acquired fund fees and expenses (expenses the Fund incurs indirectly through its investments in other investment companies) and may be higher than the ratio of expenses to average net assets shown in the Financial Highlights section of this prospectus because the ratio of expenses to average net assets does not include acquired fund fees and expenses.

[3] Columbia Wanger Asset Management, LLC (the Investment Manager) has contractually agreed to waive fees and reimburse certain expenses of the Fund, through April 30, 2023, so that ordinary operating expenses (excluding transaction costs and certain other investment-related expenses, interest and fees on borrowings and expenses associated with the Fund’s investment in other investment companies, if any) do not exceed the annual rates of 1.45% for Class A shares, 1.20% for Class Adv shares, 2.20% for Class C shares, 1.20% for Class Inst shares, 1.14% for Class Inst2 shares and 1.11% for Class Inst3 shares. This arrangement may only be amended or terminated with approval from the Fund’s Board of Trustees and the Investment Manager. The fee waivers and/or expense reimbursements shown in the table also reflect the contractual agreement of the Fund’s transfer agent, Columbia Management Investment Services Corp. (the Transfer Agent), to waive a portion of its fees through April 30, 2023, such that the Fund’s transfer agency fees do not exceed the annual rates of 0.03% of the average daily net assets of Class Inst2 shares and 0.00% of the average daily net assets of Class Inst3 shares. This arrangement may be terminated at the sole discretion of the Fund’s Board of Trustees.

[4] This charge applies to redemptions within 12 months after purchase, with certain limited exceptions.

[5] Year to Date return as of March 31, 2022: -21.84%

XML

Label

Element

Value

Columbia Acorn Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

Summary of the Fund

Objective [Heading]

rr_ObjectiveHeading

Investment Objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

Columbia Acorn^® Fund (the Fund) seeks long-term capital appreciation.

Expense [Heading]

rr_ExpenseHeading

Fees and Expenses of the Fund

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below. You may qualify for sales charge discounts if you and members of your immediate family invest, or agree to invest in the future, at least $50,000 in certain classes of shares of eligible funds distributed by Columbia Management Investment Distributors, Inc. (the Distributor). More information is available about these and other sales charge discounts and waivers from your financial intermediary, and can be found in the Choosing a Share Class section beginning on page 25 of the Fund’s prospectus, in Appendix A to the prospectus beginning on page A-1 and in Appendix S to the Statement of Additional Information (SAI) under Sales Charge Waivers beginning on page S-1.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

Shareholder Fees (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio Turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The Fund may pay transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 75% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

75.00%

Expense Breakpoint Discounts [Text]

rr_ExpenseBreakpointDiscounts

You may qualify for sales charge discounts if you and members of your immediate family invest, or agree to invest in the future, at least $50,000 in certain classes of shares of eligible funds distributed by Columbia Management Investment Distributors, Inc. (the Distributor). More information is available about these and other sales charge discounts and waivers from your financial intermediary, and can be found in the Choosing a Share Class section beginning on page 25 of the Fund’s prospectus, in Appendix A to the prospectus beginning on page A-1 and in Appendix S to the Statement of Additional Information (SAI) under Sales Charge Waivers beginning on page S-1.

Expense Breakpoint, Minimum Investment Required [Amount]

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

$ 50,000

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees

“Total annual Fund operating expenses” include acquired fund fees and expenses (expenses the Fund incurs indirectly through its investments in other investment companies) and may be higher than the ratio of expenses to average net assets shown in the Financial Highlights section of this prospectus because the ratio of expenses to average net assets does not include acquired fund fees and expenses.

Expense Example [Heading]

rr_ExpenseExampleHeading

 Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

The following example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example illustrates the hypothetical expenses that you would incur over the time periods indicated, and assumes that:

■ you invest $10,000 in the applicable class of Fund shares for the periods indicated,

■ your investment has a 5% return each year, and

■ the Fund’s total annual operating expenses remain the same as shown in the Annual Fund Operating Expenses table above.

Although your actual costs may be higher or lower, based on the assumptions listed above, your costs would be:

Strategy [Heading]

rr_StrategyHeading

Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

Under normal circumstances, the Fund invests a majority of its net assets in the common stock of small- and mid-sized companies with market capitalizations generally in the range of market capitalizations in the Russell 2500 Growth Index, the Fund's benchmark, (the Index) at the time of purchase (between $21.5 million and $30 billion as of March 31, 2022). The market capitalization range and composition of companies in the Index are subject to change. As such, the size of the companies in which the Fund invests may change. The Fund determines a company’s market capitalization at the time of investment. As long as a majority of its net assets are invested in companies within the Index, the Fund may continue to hold and make new investments in a security even if the company’s market capitalization grows beyond the market capitalization of the largest company within the Index or falls below the market capitalization of the smallest company within the Index.

Columbia Wanger Asset Management, LLC, the Fund's investment adviser (the Investment Manager), believes that stocks of small- and mid-sized companies, which generally are not as well known by financial analysts as larger companies, may offer higher return potential than stocks of larger companies. The Fund invests the majority of its assets in U.S. companies, but also may invest up to 33% of its total assets in foreign companies in developed markets (for example, Japan, Canada and the United Kingdom) and in emerging markets (for example, China, India and Brazil). The Investment Manager from time to time emphasizes one or more sectors in selecting the Fund’s investments, including the consumer discretionary, health care, and information technology sectors. 

The Investment Manager typically seeks companies with: 

■ A strong business franchise that offers growth potential. 

■ Products and services in which the company has a competitive advantage. 

■ A stock price the Investment Manager believes is reasonable relative to the assets and earning power of the company. 

The Investment Manager may sell a portfolio holding if the security reaches the Investment Manager's price target, if the company has a deterioration of fundamentals, such as failing to meet key operating benchmarks, or if the Investment Manager believes other securities are more attractive. The Investment Manager also may sell a portfolio holding to fund redemptions. 

Risk [Heading]

rr_RiskHeading

Principal Risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

An investment in the Fund involves risks, including those described below, among others. There is no assurance that the Fund will achieve its investment objective and you may lose money. The value of the Fund’s holdings may decline, and the Fund’s net asset value (NAV) and share price may go down. An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Active Management Risk. The Investment Manager’s active management of the Fund could cause the Fund to underperform its benchmark index and/or other funds with similar investment objectives and/or strategies.

Small- and Mid-Cap Company Securities Risk. Investments in small- and mid-cap companies often involve greater risks than investments in larger, more established companies because small- and mid-cap companies tend to have less predictable earnings and may lack the management experience, financial resources, product diversification and competitive strengths of larger companies. Securities of small- and mid-cap companies may be less liquid and more volatile than the securities of larger companies.

Market Risk. The Fund may incur losses due to declines in the value of one or more securities in which it invests. These declines may be due to factors affecting a particular issuer, or the result of, among other things, political, regulatory, market, economic or social developments affecting the relevant market(s) more generally. In addition, turbulence in financial markets and reduced liquidity in equity, credit and/or fixed income markets may negatively affect many issuers, which could adversely affect the Fund’s ability to price or value hard-to-value assets in thinly traded and closed markets and could cause significant redemptions and operational challenges. Global economies and financial markets are increasingly interconnected, and conditions and events in one country, region or financial market may adversely impact issuers in a different country, region or financial market. These risks may be magnified if certain events or developments adversely interrupt the global supply chain; in these and other circumstances, such risks might affect companies worldwide. As a result, local, regional or global events such as terrorism, war, other conflicts, natural disasters, disease/virus outbreaks and epidemics or other public health issues, recessions, depressions or other events – or the potential for such events – could have a significant negative impact on global economic and market conditions. 

The large-scale invasion of Ukraine by Russia in February 2022 has resulted in sanctions and market disruptions including declines in regional and global stock and commodity markets and significant devaluations of Russian currency. The extent and duration of the military action are impossible to predict but could be significant. Market disruption caused by the Russian military action, and any counter measures or responses thereto (including international sanctions, a downgrade in the country’s credit rating, purchasing and financing restrictions, boycotts, tariffs, changes in consumer or purchaser preferences, cyberattacks and espionage) could have severe adverse impacts on regional and/or global securities and commodities markets, including markets for oil and natural gas. These impacts may include reduced market liquidity, distress in credit markets, further disruption of global supply chains, increased risk of inflation, and limited access to investments in certain international markets and/or issuers. These developments and other related events could negatively impact Fund performance. 

The pandemic caused by coronavirus disease 2019 and its variants (COVID-19) has resulted in, and may continue to result in, significant global economic and societal disruption and market volatility due to disruptions in market access, resource availability, facilities operations, imposition of tariffs, export controls and supply chain disruption, among others. Such disruptions may be caused, or exacerbated by, quarantines and travel restrictions, workforce displacement and loss in human and other resources. The uncertainty surrounding the magnitude, duration, reach, costs and effects of the global pandemic, as well as actions that have been or could be taken by governmental authorities or other third parties, present unknowns that are yet to unfold. The impacts, as well as the uncertainty 

over impacts to come, of COVID-19 – and any other infectious illness outbreaks, epidemics and pandemics that may arise in the future – could negatively affect global economies and markets in ways that cannot necessarily be foreseen. In addition, the impact of infectious illness outbreaks and epidemics in less developed countries may be greater due to generally less established healthcare systems, governments and financial markets. Public health crises caused by the COVID-19 outbreak may exacerbate other pre-existing political, social and economic risks in certain countries or globally. The disruptions caused by COVID-19 could prevent the Fund from executing advantageous investment decisions in a timely manner and negatively impact the Fund’s ability to achieve its investment objective. Any such events could have a significant adverse impact on the value and risk profile of the Fund. 

Issuer Risk. An issuer in which the Fund invests may perform poorly, and the value of its securities may therefore decline, which may negatively affect the Fund’s performance. Underperformance of an issuer may be caused by poor management decisions, competitive pressures, breakthroughs in technology, reliance on suppliers, labor problems or shortages, corporate restructurings, fraudulent disclosures, natural disasters, military confrontations and actions, war, terrorism, disease/virus outbreaks and epidemics or other events, conditions and factors. 

Growth Securities Risk. Growth securities typically trade at a higher multiple of earnings than other types of equity securities. Accordingly, the market values of growth securities may never reach their expected market value and may decline in price. In addition, growth securities, at times, may not perform as well as value securities or the stock market in general, and may be out of favor with investors for varying periods of time. 

Liquidity and Trading Volume Risk. Because the Fund may invest a percentage of its assets in foreign securities, including in emerging markets, it may be subject to the liquidity and trading volume risks associated with international investing, including in emerging markets. Due to market conditions, including uncertainty regarding the price of a security, it may be difficult for the Fund to buy or sell foreign portfolio securities at a desirable time or price, which could result in investment losses and may affect the value of your investment in the Fund. This risk of portfolio illiquidity is heightened with respect to small- and mid-cap securities, generally, and foreign small- and mid-cap securities in particular. The Fund may have to lower the selling price, liquidate other investments, or forego another, more appealing investment opportunity as a result of illiquidity in the markets. The Fund may also be limited in its ability to execute favorable trades in foreign portfolio securities in response to changes in share prices and fundamentals, and may be forced to dispose of securities under disadvantageous circumstances and at a loss. As the Fund grows in size or, conversely, if it faces significant redemption pressure, these considerations take on increasing significance and may adversely impact performance. 

Sector Risk. At times, the Fund may have a significant portion of its assets invested in securities of companies conducting business within one or more economic sectors, including the consumer discretionary, health care, and information technology sectors. Companies in the same sector may be similarly affected by economic, regulatory, political or market events or conditions, which may make the Fund more vulnerable to unfavorable developments in that sector than funds that invest more broadly. Generally, the more broadly the Fund invests, the more it spreads risk and potentially reduces the risks of loss and volatility. 

■ Consumer Discretionary Sector. The Fund is more susceptible to the particular risks that may affect companies in the consumer discretionary sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the consumer discretionary sector are subject to certain risks, including fluctuations in the performance of the overall domestic and international economy, interest rate changes, increased competition and consumer confidence. Performance of such companies may be affected by factors including reduced disposable household income, reduced consumer spending, and changing demographics and consumer tastes. 

■ Health Care Sector. The Fund is more susceptible to the particular risks that may affect companies in the health care sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the health care sector are subject to certain risks, including restrictions on government reimbursement for medical expenses, government approval of medical products and services, competitive pricing pressures, and the rising cost of medical products and services (especially for companies dependent upon a relatively limited number of products or 

services), among others. Performance of such companies may be affected by factors including, government regulation, obtaining and protecting patents (or the failure to do so), product liability and other similar litigation as well as product obsolescence. 

■ Information Technology Sector. The Fund is more susceptible to the particular risks that may affect companies in the information technology sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the information technology sector are subject to certain risks, including the risk that new services, equipment or technologies will not be accepted by consumers and businesses or will become rapidly obsolete. Performance of such companies may be affected by factors including obtaining and protecting patents (or the failure to do so) and significant competitive pressures, including aggressive pricing of their products or services, new market entrants, competition for market share and short product cycles due to an accelerated rate of technological developments. Such competitive pressures may lead to limited earnings and/or falling profit margins. As a result, the value of their securities may fall or fail to rise. In addition, many information technology sector companies have limited operating histories and prices of these companies’ securities historically have been more volatile than other securities, especially over the short term. Some companies in the information technology sector are facing increased government and regulatory scrutiny and may be subject to adverse government or regulatory action, which could negatively impact the value of their securities. 

Foreign Securities Risk. Investments in or exposure to securities of foreign companies may involve heightened risks relative to investments in or exposure to securities of U.S. companies. Investing in securities of foreign companies subjects the Fund to the risks associated with an issuer’s (and any of its related companies’) country of organization and places of business operations, including risks related to political, regulatory, economic, social, diplomatic and other conditions or events (including, for example, military confrontations and actions, war, other conflicts, terrorism and disease/virus outbreaks and epidemics) occurring in the country or region, as well as risks associated with less developed custody and settlement practices. Foreign securities may be more volatile and less liquid than securities of U.S. companies, and are subject to the risks associated with potential imposition of economic and other sanctions against a particular foreign country, its nationals or industries or businesses within the country. In addition, foreign governments may impose withholding or other taxes on the Fund’s income, capital gains or proceeds from the disposition of foreign securities, which could reduce the Fund’s return on such securities. 

Operational and Settlement Risks of Foreign Securities. The Fund’s foreign securities are generally held outside the United States in the primary market for the securities in the custody of foreign sub-custodians. Some countries have limited governmental oversight and regulation, which increases the risk of corruption and fraud and the possibility of losses to the Fund. In particular, under certain circumstances, foreign securities may settle on a delayed delivery basis, meaning that the Fund may be required to make payment for securities before the Fund has actually received delivery of the securities or deliver securities prior to the receipt of payment. As a result, there is a risk that the security will not be delivered to the Fund or that payment will not be received. Losses can also result from lost, stolen or counterfeit securities; defaults by brokers and banks; failures or defects of the settlement system; or poor and improper record keeping by registrars and issuers. 

Share Blocking. In certain non-U.S. markets, an issuer’s securities are blocked from trading for a specified number of days before and, in certain instances, after a shareholder meeting. The blocking period can last up to several weeks. Share blocking may prevent the Fund from buying or selling securities during this period. As a consequence of these restrictions, the Investment Manager, on behalf of the Fund, may abstain from voting proxies in markets that require share blocking. 

Emerging Market Securities Risk. Securities issued by foreign governments or companies in emerging market countries are more likely to have greater exposure to the risks of investing in foreign securities that are described in Foreign Securities Risk. In addition, emerging market countries are more likely to experience instability resulting, for example, from rapid changes or developments in social, political, economic or other conditions. Their economies are usually less mature and their securities markets are typically less developed with more limited trading activity (i.e., lower trading volumes and less liquidity) than more developed countries. Emerging market securities tend to be more volatile, and may be more susceptible to market manipulation, than securities in more developed markets. Many emerging market countries are heavily dependent on international trade and have fewer trading partners, which makes them more sensitive to world commodity prices and economic downturns in other countries, and some have a 

higher risk of currency devaluations. Due to the differences in the nature and quality of financial information of issuers of emerging market securities, including auditing and financial reporting standards, financial information and disclosures about such issuers may be unavailable or, if made available, may be considerably less reliable than publicly available information about other foreign securities. 

Risk Lose Money [Text]

rr_RiskLoseMoney

There is no assurance that the Fund will achieve its investment objective and you may lose money.

Risk Not Insured Depository Institution [Text]

rr_RiskNotInsuredDepositoryInstitution

An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Performance Information

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following bar chart and table show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. The bar chart shows how the Fund’s Class Inst share performance has varied for each full calendar year shown. The table below the bar chart compares the Fund’s returns for the periods shown with the Russell 2500 Growth Index.

The performance of one or more share classes shown in the Average Annual Total Returns table below includes the Fund’s Class Inst share returns (adjusted to reflect the higher class-related operating expenses of such classes, where applicable) for periods prior to the indicated inception date of such share classes. Except for differences in fees and expenses, all share classes of the Fund would have substantially similar annual returns because all share classes of the Fund invest in the same portfolio of securities.

The after-tax returns shown in the Average Annual Total Returns table below are calculated using the highest historical individual U.S. federal marginal income tax rates in effect during the period indicated in the table and do not reflect the impact of state, local or foreign taxes. Your actual after-tax returns will depend on your personal tax situation and may differ from those shown in the table. In addition, the after-tax returns shown in the table do not apply to shares held in tax-advantaged accounts such as 401(k) plans or Individual Retirement Accounts (IRAs). The after-tax returns are shown only for Class Inst shares and will vary for other share classes.

The Fund’s past performance (before and after taxes) is no guarantee of how the Fund will perform in the future. Updated performance information can be obtained by calling toll-free 800.345.6611 or visiting columbiathreadneedleus.com.

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following bar chart and table show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. The bar chart shows how the Fund’s Class Inst share performance has varied for each full calendar year shown. The table below the bar chart compares the Fund’s returns for the periods shown with the Russell 2500 Growth Index.

Performance Availability Phone [Text]

rr_PerformanceAvailabilityPhone

800.345.6611

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

columbiathreadneedleus.com

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

The Fund’s past performance (before and after taxes) is no guarantee of how the Fund will perform in the future.

Bar Chart [Heading]

rr_BarChartHeading

Year by Year Total Return (%) as of December 31 Each Year*

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

Best and Worst Quarterly Returns During the Period Shown in the Bar Chart Best 2nd Quarter 2020 28.34% Worst 1st Quarter 2020 -21.29%

Performance Table Heading

rr_PerformanceTableHeading

 Average Annual Total Returns After Applicable Sales Charges (for periods ended December 31, 2021)

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

The after-tax returns shown in the Average Annual Total Returns table below are calculated using the highest historical individual U.S. federal marginal income tax rates in effect during the period indicated in the table and do not reflect the impact of state, local or foreign taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

In addition, the after-tax returns shown in the table do not apply to shares held in tax-advantaged accounts such as 401(k) plans or Individual Retirement Accounts (IRAs).

Performance Table One Class of after Tax Shown [Text]

rr_PerformanceTableOneClassOfAfterTaxShown

The after-tax returns are shown only for Class Inst shares and will vary for other share classes.

Columbia Acorn Fund | Class A

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

5.75%

Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)

rr_MaximumDeferredSalesChargeOverOther

1.00%

^[1]

Management fees

rr_ManagementFeesOverAssets

0.67%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

0.25%

Other expenses

rr_OtherExpensesOverAssets

0.16%

Total annual Fund operating expenses

rr_ExpensesOverAssets

1.08%

^[2]

Expenses Deferred Charges [Text Block]

rr_ExpensesDeferredChargesTextBlock

This charge is imposed on certain investments of between $1 million and $50 million redeemed within 18 months after purchase, as follows: 1.00% if redeemed within 12 months after purchase, and 0.50% if redeemed more than 12, but less than 18, months after purchase, with certain limited exceptions.

1 year

rr_ExpenseExampleYear01

$ 679

3 years

rr_ExpenseExampleYear03

899

5 years

rr_ExpenseExampleYear05

1,136

10 years

rr_ExpenseExampleYear10

1,816

1 year

rr_ExpenseExampleNoRedemptionYear01

679

3 years

rr_ExpenseExampleNoRedemptionYear03

899

5 years

rr_ExpenseExampleNoRedemptionYear05

1,136

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 1,816

1 Year

rr_AverageAnnualReturnYear01

2.57%

5 Years

rr_AverageAnnualReturnYear05

14.64%

10 Years

rr_AverageAnnualReturnYear10

12.68%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Oct. 16, 2000

Columbia Acorn Fund | Class C

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)

rr_MaximumDeferredSalesChargeOverOther

1.00%

^[3]

Management fees

rr_ManagementFeesOverAssets

0.67%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

1.00%

Other expenses

rr_OtherExpensesOverAssets

0.16%

Total annual Fund operating expenses

rr_ExpensesOverAssets

1.83%

^[2]

Expenses Deferred Charges [Text Block]

rr_ExpensesDeferredChargesTextBlock

This charge applies to redemptions within 12 months after purchase, with certain limited exceptions.

1 year

rr_ExpenseExampleYear01

$ 286

3 years

rr_ExpenseExampleYear03

576

5 years

rr_ExpenseExampleYear05

990

10 years

rr_ExpenseExampleYear10

1,951

1 year

rr_ExpenseExampleNoRedemptionYear01

186

3 years

rr_ExpenseExampleNoRedemptionYear03

576

5 years

rr_ExpenseExampleNoRedemptionYear05

990

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 1,951

1 Year

rr_AverageAnnualReturnYear01

7.10%

5 Years

rr_AverageAnnualReturnYear05

15.11%

10 Years

rr_AverageAnnualReturnYear10

12.51%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Oct. 16, 2000

Columbia Acorn Fund | Class Inst

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)

rr_MaximumDeferredSalesChargeOverOther

none

Management fees

rr_ManagementFeesOverAssets

0.67%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.16%

Total annual Fund operating expenses

rr_ExpensesOverAssets

0.83%

^[2]

1 year

rr_ExpenseExampleYear01

$ 85

3 years

rr_ExpenseExampleYear03

265

5 years

rr_ExpenseExampleYear05

460

10 years

rr_ExpenseExampleYear10

1,025

1 year

rr_ExpenseExampleNoRedemptionYear01

85

3 years

rr_ExpenseExampleNoRedemptionYear03

265

5 years

rr_ExpenseExampleNoRedemptionYear05

460

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 1,025

2012

rr_AnnualReturn2012

17.93%

^[4]

2013

rr_AnnualReturn2013

30.90%

^[4]

2014

rr_AnnualReturn2014

0.82%

^[4]

2015

rr_AnnualReturn2015

(1.57%)

^[4]

2016

rr_AnnualReturn2016

10.39%

^[4]

2017

rr_AnnualReturn2017

25.24%

^[4]

2018

rr_AnnualReturn2018

(5.09%)

^[4]

2019

rr_AnnualReturn2019

26.60%

^[4]

2020

rr_AnnualReturn2020

29.51%

^[4]

2021

rr_AnnualReturn2021

8.99%

^[4]

Year to Date Return, Label

rr_YearToDateReturnLabel

Year to Date return

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Mar. 31, 2022

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

(17.51%)

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2020

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

28.34%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Mar. 31, 2020

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(21.29%)

1 Year

rr_AverageAnnualReturnYear01

8.99%

5 Years

rr_AverageAnnualReturnYear05

16.26%

10 Years

rr_AverageAnnualReturnYear10

13.64%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Jun. 10, 1970

Columbia Acorn Fund | Class Adv

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)

rr_MaximumDeferredSalesChargeOverOther

none

Management fees

rr_ManagementFeesOverAssets

0.67%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.16%

Total annual Fund operating expenses

rr_ExpensesOverAssets

0.83%

^[2]

1 year

rr_ExpenseExampleYear01

$ 85

3 years

rr_ExpenseExampleYear03

265

5 years

rr_ExpenseExampleYear05

460

10 years

rr_ExpenseExampleYear10

1,025

1 year

rr_ExpenseExampleNoRedemptionYear01

85

3 years

rr_ExpenseExampleNoRedemptionYear03

265

5 years

rr_ExpenseExampleNoRedemptionYear05

460

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 1,025

1 Year

rr_AverageAnnualReturnYear01

9.03%

5 Years

rr_AverageAnnualReturnYear05

16.27%

10 Years

rr_AverageAnnualReturnYear10

13.61%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Nov. 08, 2012

Columbia Acorn Fund | Class Inst2

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)

rr_MaximumDeferredSalesChargeOverOther

none

Management fees

rr_ManagementFeesOverAssets

0.67%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.14%

Total annual Fund operating expenses

rr_ExpensesOverAssets

0.81%

^[2]

1 year

rr_ExpenseExampleYear01

$ 83

3 years

rr_ExpenseExampleYear03

259

5 years

rr_ExpenseExampleYear05

450

10 years

rr_ExpenseExampleYear10

1,002

1 year

rr_ExpenseExampleNoRedemptionYear01

83

3 years

rr_ExpenseExampleNoRedemptionYear03

259

5 years

rr_ExpenseExampleNoRedemptionYear05

450

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 1,002

1 Year

rr_AverageAnnualReturnYear01

9.09%

5 Years

rr_AverageAnnualReturnYear05

16.30%

10 Years

rr_AverageAnnualReturnYear10

13.67%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Nov. 08, 2012

Columbia Acorn Fund | Class Inst3

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)

rr_MaximumDeferredSalesChargeOverOther

none

Management fees

rr_ManagementFeesOverAssets

0.67%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.09%

Total annual Fund operating expenses

rr_ExpensesOverAssets

0.76%

^[2]

1 year

rr_ExpenseExampleYear01

$ 78

3 years

rr_ExpenseExampleYear03

243

5 years

rr_ExpenseExampleYear05

422

10 years

rr_ExpenseExampleYear10

942

1 year

rr_ExpenseExampleNoRedemptionYear01

78

3 years

rr_ExpenseExampleNoRedemptionYear03

243

5 years

rr_ExpenseExampleNoRedemptionYear05

422

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 942

1 Year

rr_AverageAnnualReturnYear01

9.16%

5 Years

rr_AverageAnnualReturnYear05

16.37%

10 Years

rr_AverageAnnualReturnYear10

13.73%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Nov. 08, 2012

Columbia Acorn Fund | returns after taxes on distributions | Class Inst

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

3.11%

5 Years

rr_AverageAnnualReturnYear05

11.83%

10 Years

rr_AverageAnnualReturnYear10

8.86%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Jun. 10, 1970

Columbia Acorn Fund | returns after taxes on distributions and sale of Fund shares | Class Inst

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

8.92%

5 Years

rr_AverageAnnualReturnYear05

12.14%

10 Years

rr_AverageAnnualReturnYear10

9.79%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Jun. 10, 1970

Columbia Acorn Fund | Russell 2500 Growth Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

5.04%

5 Years

rr_AverageAnnualReturnYear05

17.65%

10 Years

rr_AverageAnnualReturnYear10

15.75%

[1] This charge is imposed on certain investments of between $1 million and $50 million redeemed within 18 months after purchase, as follows: 1.00% if redeemed within 12 months after purchase, and 0.50% if redeemed more than 12, but less than 18, months after purchase, with certain limited exceptions.

[2] “Total annual Fund operating expenses” include acquired fund fees and expenses (expenses the Fund incurs indirectly through its investments in other investment companies) and may be higher than the ratio of expenses to average net assets shown in the Financial Highlights section of this prospectus because the ratio of expenses to average net assets does not include acquired fund fees and expenses.

[3] This charge applies to redemptions within 12 months after purchase, with certain limited exceptions.

[4] Year to Date return as of March 31, 2022: -17.51%

XML

Label

Element

Value

Columbia Acorn International

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

Summary of the Fund

Objective [Heading]

rr_ObjectiveHeading

Investment Objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

Columbia Acorn International^® (the Fund) seeks long-term capital appreciation.

Expense [Heading]

rr_ExpenseHeading

Fees and Expenses of the Fund

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below. You may qualify for sales charge discounts if you and members of your immediate family invest, or agree to invest in the future, at least $50,000 in certain classes of shares of eligible funds distributed by Columbia Management Investment Distributors, Inc. (the Distributor). More information is available about these and other sales charge discounts and waivers from your financial intermediary, and can be found in the Choosing a Share Class section beginning on page 28 of the Fund’s prospectus, in Appendix A to the prospectus beginning on page A-1 and in Appendix S to the Statement of Additional Information (SAI) under Sales Charge Waivers beginning on page S-1.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

Shareholder Fees (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

April 30, 2023

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio Turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The Fund may pay transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 27% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

27.00%

Expense Breakpoint Discounts [Text]

rr_ExpenseBreakpointDiscounts

You may qualify for sales charge discounts if you and members of your immediate family invest, or agree to invest in the future, at least $50,000 in certain classes of shares of eligible funds distributed by Columbia Management Investment Distributors, Inc. (the Distributor). More information is available about these and other sales charge discounts and waivers from your financial intermediary, and can be found in the Choosing a Share Class section beginning on page 28 of the Fund’s prospectus, in Appendix A to the prospectus beginning on page A-1 and in Appendix S to the Statement of Additional Information (SAI) under Sales Charge Waivers beginning on page S-1.

Expense Breakpoint, Minimum Investment Required [Amount]

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

$ 50,000

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees

“Total annual Fund operating expenses” include acquired fund fees and expenses (expenses the Fund incurs indirectly through its investments in other investment companies) and may be higher than the ratio of expenses to average net assets shown in the Financial Highlights section of this prospectus because the ratio of expenses to average net assets does not include acquired fund fees and expenses.

Expense Example [Heading]

rr_ExpenseExampleHeading

 Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

The following example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example illustrates the hypothetical expenses that you would incur over the time periods indicated, and assumes that:

■ you invest $10,000 in the applicable class of Fund shares for the periods indicated,

■ your investment has a 5% return each year, and

■ the Fund’s total annual operating expenses remain the same as shown in the Annual Fund Operating Expenses table above.

Since the waivers and/or reimbursements shown in the Annual Fund Operating Expenses table above expire as indicated in the preceding table, they are only reflected in the 1 year example and the first year of the other examples. Although your actual costs may be higher or lower, based on the assumptions listed above, your costs would be:

Strategy [Heading]

rr_StrategyHeading

Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

Under normal circumstances, the Fund invests at least 75% of its net assets in foreign companies in developed markets (for example, Japan, Canada and the United Kingdom) and in emerging markets (for example, China, India and Brazil).

Under normal circumstances, the Fund invests a majority of its net assets in the common stock of small- and mid-sized companies with market capitalizations generally in the range of market capitalizations in the MSCI ACWI ex USA SMID Cap Growth Index (Net), the Fund's primary benchmark, (the Index) at the time of purchase (between $55.8 million and $29.7 billion as of March 31, 2022). The market capitalization range and composition of companies in the Index are subject to change. As such, the size of the companies in which the Fund invests may change. The Fund determines a company’s market capitalization at the time of investment. As long as a majority of its net assets are invested in companies within the Index, the Fund may continue to hold and make new investments in a security even if the company’s market capitalization grows beyond the market capitalization of the largest company within the Index or falls below the market capitalization of the smallest company within the Index. The Investment Manager from time to time emphasizes one or more sectors in selecting the Fund’s investments, including the industrials and information technology sectors. 

Columbia Wanger Asset Management, LLC, the Fund's investment adviser (the Investment Manager), believes that stocks of small- and mid-sized companies, which generally are not as well known by financial analysts as larger companies, may offer higher return potential than stocks of larger companies. The Fund also may invest in larger-sized companies. 

The Investment Manager typically seeks companies with: 

■ A strong business franchise that offers growth potential. 

■ Products and services in which the company has a competitive advantage. 

■ A stock price the Investment Manager believes is reasonable relative to the assets and earning power of the company. 

The Investment Manager may sell a portfolio holding if the security reaches the Investment Manager's price target, if the company has a deterioration of fundamentals, such as failing to meet key operating benchmarks, or if the Investment Manager believes other securities are more attractive. The Investment Manager also may sell a portfolio holding to fund redemptions. 

Risk [Heading]

rr_RiskHeading

Principal Risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

An investment in the Fund involves risks, including those described below, among others. There is no assurance that the Fund will achieve its investment objective and you may lose money. The value of the Fund’s holdings may decline, and the Fund’s net asset value (NAV) and share price may go down. An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Active Management Risk. The Investment Manager’s active management of the Fund could cause the Fund to underperform its benchmark index and/or other funds with similar investment objectives and/or strategies.

Market Risk. The Fund may incur losses due to declines in the value of one or more securities in which it invests. These declines may be due to factors affecting a particular issuer, or the result of, among other things, political, regulatory, market, economic or social developments affecting the relevant market(s) more generally. In addition, turbulence in financial markets and reduced liquidity in equity, credit and/or fixed income markets may negatively affect many issuers, which could adversely affect the Fund’s ability to price or value hard-to-value assets in thinly traded and closed markets and could cause significant redemptions and operational challenges. Global economies and financial markets are increasingly interconnected, and conditions and events in one country, region or financial market may adversely impact issuers in a different country, region or financial market. These risks may be magnified if certain events or developments adversely interrupt the global supply chain; in these and other circumstances, such risks might affect companies worldwide. As a result, local, regional or global events such as terrorism, war, other conflicts, natural disasters, disease/virus outbreaks and epidemics or other public health issues, recessions, depressions or other events – or the potential for such events – could have a significant negative impact on global economic and market conditions. 

The large-scale invasion of Ukraine by Russia in February 2022 has resulted in sanctions and market disruptions including declines in regional and global stock and commodity markets and significant devaluations of Russian currency. The extent and duration of the military action are impossible to predict but could be significant. Market disruption caused by the Russian military action, and any counter measures or responses thereto (including international sanctions, a downgrade in the country’s credit rating, purchasing and financing restrictions, boycotts, tariffs, changes in consumer or purchaser preferences, cyberattacks and espionage) could have severe adverse impacts on regional and/or global securities and commodities markets, including markets for oil and natural gas. These impacts may include reduced market liquidity, distress in credit markets, further disruption of global supply chains, increased risk of inflation, and limited access to investments in certain international markets and/or issuers. These developments and other related events could negatively impact Fund performance. 

The pandemic caused by coronavirus disease 2019 and its variants (COVID-19) has resulted in, and may continue to result in, significant global economic and societal disruption and market volatility due to disruptions in market access, resource availability, facilities operations, imposition of tariffs, export controls and supply chain disruption, among others. Such disruptions may be caused, or exacerbated by, quarantines and travel restrictions, workforce 

displacement and loss in human and other resources. The uncertainty surrounding the magnitude, duration, reach, costs and effects of the global pandemic, as well as actions that have been or could be taken by governmental authorities or other third parties, present unknowns that are yet to unfold. The impacts, as well as the uncertainty over impacts to come, of COVID-19 – and any other infectious illness outbreaks, epidemics and pandemics that may arise in the future – could negatively affect global economies and markets in ways that cannot necessarily be foreseen. In addition, the impact of infectious illness outbreaks and epidemics in less developed countries may be greater due to generally less established healthcare systems, governments and financial markets. Public health crises caused by the COVID-19 outbreak may exacerbate other pre-existing political, social and economic risks in certain countries or globally. The disruptions caused by COVID-19 could prevent the Fund from executing advantageous investment decisions in a timely manner and negatively impact the Fund’s ability to achieve its investment objective. Any such events could have a significant adverse impact on the value and risk profile of the Fund. 

Small- and Mid-Cap Company Securities Risk. Investments in small- and mid-cap companies often involve greater risks than investments in larger, more established companies because small- and mid-cap companies tend to have less predictable earnings and may lack the management experience, financial resources, product diversification and competitive strengths of larger companies. Securities of small- and mid-cap companies may be less liquid and more volatile than the securities of larger companies. 

Foreign Securities Risk. Investments in or exposure to securities of foreign companies may involve heightened risks relative to investments in or exposure to securities of U.S. companies. Investing in securities of foreign companies subjects the Fund to the risks associated with an issuer’s (and any of its related companies’) country of organization and places of business operations, including risks related to political, regulatory, economic, social, diplomatic and other conditions or events (including, for example, military confrontations and actions, war, other conflicts, terrorism and disease/virus outbreaks and epidemics) occurring in the country or region, as well as risks associated with less developed custody and settlement practices. Foreign securities may be more volatile and less liquid than securities of U.S. companies, and are subject to the risks associated with potential imposition of economic and other sanctions against a particular foreign country, its nationals or industries or businesses within the country. In addition, foreign governments may impose withholding or other taxes on the Fund’s income, capital gains or proceeds from the disposition of foreign securities, which could reduce the Fund’s return on such securities. 

Operational and Settlement Risks of Foreign Securities. The Fund’s foreign securities are generally held outside the United States in the primary market for the securities in the custody of foreign sub-custodians. Some countries have limited governmental oversight and regulation, which increases the risk of corruption and fraud and the possibility of losses to the Fund. In particular, under certain circumstances, foreign securities may settle on a delayed delivery basis, meaning that the Fund may be required to make payment for securities before the Fund has actually received delivery of the securities or deliver securities prior to the receipt of payment. As a result, there is a risk that the security will not be delivered to the Fund or that payment will not be received. Losses can also result from lost, stolen or counterfeit securities; defaults by brokers and banks; failures or defects of the settlement system; or poor and improper record keeping by registrars and issuers. 

Share Blocking. In certain non-U.S. markets, an issuer’s securities are blocked from trading for a specified number of days before and, in certain instances, after a shareholder meeting. The blocking period can last up to several weeks. Share blocking may prevent the Fund from buying or selling securities during this period. As a consequence of these restrictions, the Investment Manager, on behalf of the Fund, may abstain from voting proxies in markets that require share blocking. 

Emerging Market Securities Risk. Securities issued by foreign governments or companies in emerging market countries, such as China, Russia and certain countries in Eastern Europe, the Middle East, Asia, Latin America or Africa, are more likely to have greater exposure to the risks of investing in foreign securities that are described in Foreign Securities Risk. In addition, emerging market countries are more likely to experience instability resulting, for example, from rapid changes or developments in social, political, economic or other conditions. Their economies are usually less mature and their securities markets are typically less developed with more limited trading activity (i.e., lower trading volumes and less liquidity) than more developed countries. Emerging market securities tend to be more volatile, and may be more susceptible to market manipulation, than securities in more developed markets. 

Many emerging market countries are heavily dependent on international trade and have fewer trading partners, which makes them more sensitive to world commodity prices and economic downturns in other countries, and some have a higher risk of currency devaluations. Due to the differences in the nature and quality of financial information of issuers of emerging market securities, including auditing and financial reporting standards, financial information and disclosures about such issuers may be unavailable or, if made available, may be considerably less reliable than publicly available information about other foreign securities. 

Operational and Settlement Risks of Securities in Emerging Markets. Foreign sub-custodians in emerging markets may be recently organized, lack extensive operating experience or lack effective government oversight or regulation. In addition, there may be legal restrictions or limitations on the ability of the Fund to recover assets held in custody by a foreign sub-custodian in the event of the bankruptcy of the sub-custodian. There may also be a greater risk that settlement may be delayed and that cash or securities of the Fund may be lost because of failures of or defects in the system, including fraud or corruption. Settlement systems in emerging markets also have a higher risk of failed trades. 

Risks Related to Currencies and Corporate Actions in Emerging Markets. Risks related to currencies and corporate actions are also greater in emerging market countries than in developed countries. Emerging market currencies may not have an active trading market and are subject to a higher risk of currency devaluations. 

Risks Related to Corporate and Securities Laws in Emerging Markets. Securities laws in emerging markets may be relatively new and unsettled and, consequently, there is a risk of rapid and unpredictable change in laws regarding foreign investment, securities regulation, title to securities and shareholder rights. 

Liquidity and Trading Volume Risk. Due to market conditions, including uncertainty regarding the price of a security, it may be difficult for the Fund to buy or sell portfolio securities at a desirable time or price, which could result in investment losses. This risk of portfolio illiquidity is heightened with respect to small- and mid-cap securities, generally, and foreign small- and mid-cap securities in particular. The Fund may have to lower the selling price, liquidate other investments, or forego another, more appealing investment opportunity as a result of illiquidity in the markets. The Fund may also be limited in its ability to execute favorable trades in portfolio securities in response to changes in share prices and fundamentals, and may be forced to dispose of securities under disadvantageous circumstances and at a loss. As the Fund grows in size or, conversely, if it faces significant redemption pressure, these considerations take on increasing significance and may adversely impact performance. 

Geographic Focus Risk. The Fund may be particularly susceptible to risks related to economic, political, regulatory or other events or conditions affecting issuers and countries within the specific geographic regions in which the Fund invests. The Fund’s NAV may be more volatile than the NAV of a more geographically diversified fund. 

■ Asia Pacific Region. Many of the countries in the Asia Pacific region are considered underdeveloped or developing, including from a political, economic and/or social perspective, and may have relatively unstable governments and economies based on limited business, industries and/or natural resources or commodities. Events in any one country within the region may impact other countries in the region or the region as a whole. As a result, events in the region will generally have a greater effect on the Fund than if the Fund were more geographically diversified. This could result in increased volatility in the value of the Fund’s investments and losses for the Fund. Also, securities of some companies in the region can be less liquid than U.S. or other foreign securities, potentially making it difficult for the Fund to sell such securities at a desirable time and price. 

■ Europe. The Fund is particularly susceptible to risks related to economic, political, regulatory or other events or conditions, including acts of war or other conflicts in the region, affecting issuers and countries in Europe. Countries in Europe are often closely connected and interdependent, and events in one European country can have an adverse impact on, and potentially spread to, other European countries. In addition, significant private and public sectors’ debt problems of a single European Union (EU) country can pose economic risks to the EU as a whole. As a result, the Fund’s NAV may be more volatile than the NAV of a more geographically diversified fund. If securities of issuers in Europe fall out of favor, it may cause the Fund to underperform other funds that do not focus their investments in this region of the world. The departure of the United Kingdom (UK) from the EU single market became effective January 1, 2021 with the end of the Brexit transition period and the post-Brexit trade deal between the UK and EU taking effect on December 31, 2020. The impact of any partial or complete dissolution of 

the EU on the UK and European economies and the broader global economy could be significant, resulting in negative impacts on currency and financial markets generally, such as increased volatility and illiquidity, and potentially lower economic growth in markets in Europe, which may adversely affect the value of your investment in the Fund. 

■ Japan. The Fund is particularly susceptible to the social, political, economic, regulatory and other conditions or events that may affect Japan’s economy. The Japanese economy is heavily dependent upon international trade, including, among other things, the export of finished goods and the import of oil and other commodities and raw materials. Because of its trade dependence, the Japanese economy is particularly exposed to the risks of currency fluctuation, foreign trade policy and regional and global economic disruption, including the risk of increased tariffs, embargoes, and other trade limitations or factors. Strained relationships between Japan and its neighboring countries, including China, South Korea and North Korea, based on historical grievances, territorial disputes, and defense concerns, may also cause uncertainty in Japanese markets. As a result, additional tariffs, other trade barriers, or boycotts may have an adverse impact on the Japanese economy. Japanese government policy has been characterized by economic regulation, intervention, protectionism and large government deficits. The Japanese economy is also challenged by an unstable financial services sector, highly leveraged corporate balance sheets and extensive cross-ownership among major corporations. Structural social and labor market changes, including an aging workforce, population decline and traditional aversion to labor mobility may adversely affect Japan’s economic competitiveness and growth potential. The potential for natural disasters, such as earthquakes, volcanic eruptions, typhoons and tsunamis, could also have significant negative effects on Japan’s economy. As a result of the Fund’s investment in Japanese securities, the Fund’s NAV may be more volatile than the NAV of a more geographically diversified fund. If securities of issuers in Japan fall out of favor, it may cause the Fund to underperform other funds that do not focus their investments in Japan. 

Sector Risk. At times, the Fund may have a significant portion of its assets invested in securities of companies conducting business within one or more economic sectors, including the industrials and information technology sectors. Companies in the same sector may be similarly affected by economic, regulatory, political or market events or conditions, which may make the Fund more vulnerable to unfavorable developments in that sector than funds that invest more broadly. Generally, the more broadly the Fund invests, the more it spreads risk and potentially reduces the risks of loss and volatility. 

■ Industrials Sector. The Fund is more susceptible to the particular risks that may affect companies in the industrials sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the industrials sector are subject to certain risks, including changes in supply and demand for their specific product or service and for industrial sector products in general, including decline in demand for such products due to rapid technological developments and frequent new product introduction. Performance of such companies may be affected by factors including government regulation, world events, economic conditions and risks for environmental damage and product liability claims. 

■ Information Technology Sector. The Fund is more susceptible to the particular risks that may affect companies in the information technology sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the information technology sector are subject to certain risks, including the risk that new services, equipment or technologies will not be accepted by consumers and businesses or will become rapidly obsolete. Performance of such companies may be affected by factors including obtaining and protecting patents (or the failure to do so) and significant competitive pressures, including aggressive pricing of their products or services, new market entrants, competition for market share and short product cycles due to an accelerated rate of technological developments. Such competitive pressures may lead to limited earnings and/or falling profit margins. As a result, the value of their securities may fall or fail to rise. In addition, many information technology sector companies have limited operating histories and prices of these companies’ securities historically have been more volatile than other securities, especially over the short term. Some companies in the information technology sector are facing increased government and regulatory scrutiny and may be subject to adverse government or regulatory action, which could negatively impact the value of their securities. 

Foreign Currency Risk. The performance of the Fund may be materially affected positively or negatively by foreign currency strength or weakness relative to the U.S. dollar, particularly if the Fund invests a significant percentage of its assets in foreign securities or other assets denominated in currencies other than the U.S. dollar. 

Issuer Risk. An issuer in which the Fund invests may perform poorly, and the value of its securities may therefore decline, which may negatively affect the Fund’s performance. Underperformance of an issuer may be caused by poor management decisions, competitive pressures, breakthroughs in technology, reliance on suppliers, labor problems or shortages, corporate restructurings, fraudulent disclosures, natural disasters, military confrontations and actions, war, terrorism, disease/virus outbreaks and epidemics or other events, conditions and factors. 

Growth Securities Risk. Growth securities typically trade at a higher multiple of earnings than other types of equity securities. Accordingly, the market values of growth securities may never reach their expected market value and may decline in price. In addition, growth securities, at times, may not perform as well as value securities or the stock market in general, and may be out of favor with investors for varying periods of time. 

Risk Lose Money [Text]

rr_RiskLoseMoney

There is no assurance that the Fund will achieve its investment objective and you may lose money.

Risk Not Insured Depository Institution [Text]

rr_RiskNotInsuredDepositoryInstitution

An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Performance Information

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following bar chart and table show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. The bar chart shows how the Fund’s Class Inst share performance has varied for each full calendar year shown. The table below the bar chart compares the Fund’s returns for the periods shown with those of the MSCI ACWI ex USA SMID Cap Growth Index (Net), the Fund's primary benchmark, and those of the MSCI ACWI ex USA SMID Cap Index (Net), the Fund's secondary benchmark. The MSCI ACWI ex USA SMID Cap Growth Index (Net) captures mid- and small-cap securities exhibiting overall growth style characteristics across 22 developed market countries and 24 emerging market countries. The MSCI ACWI ex USA SMID Cap Index (Net) captures mid- and small-cap representation across 22 of 23 developed market countries (excluding the United States) and 24 emerging market countries. As of March 31, 2022, the MSCI ACWI ex USA SMID Cap Index (Net) had 5,541 constituents and covered approximately 28% of the free float-adjusted market capitalization in each country. 

The performance of one or more share classes shown in the Average Annual Total Returns table below includes the Fund’s Class Inst share returns (adjusted to reflect the higher class-related operating expenses of such classes, where applicable) for periods prior to the indicated inception date of such share classes. Except for differences in fees and expenses, all share classes of the Fund would have substantially similar annual returns because all share classes of the Fund invest in the same portfolio of securities. 

The after-tax returns shown in the Average Annual Total Returns table below are calculated using the highest historical individual U.S. federal marginal income tax rates in effect during the period indicated in the table and do not reflect the impact of state, local or foreign taxes. Your actual after-tax returns will depend on your personal tax situation and may differ from those shown in the table. In addition, the after-tax returns shown in the table do not apply to shares held in tax-advantaged accounts such as 401(k) plans or Individual Retirement Accounts (IRAs). The after-tax returns are shown only for Class Inst shares and will vary for other share classes. 

The Fund’s past performance (before and after taxes) is no guarantee of how the Fund will perform in the future. Updated performance information can be obtained by calling toll-free 800.345.6611 or visiting columbiathreadneedleus.com. 

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following bar chart and table show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. The bar chart shows how the Fund’s Class Inst share performance has varied for each full calendar year shown. The table below the bar chart compares the Fund’s returns for the periods shown with those of the MSCI ACWI ex USA SMID Cap Growth Index (Net), the Fund's primary benchmark, and those of the MSCI ACWI ex USA SMID Cap Index (Net), the Fund's secondary benchmark.

Performance Availability Phone [Text]

rr_PerformanceAvailabilityPhone

800.345.6611

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

columbiathreadneedleus.com

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

The Fund’s past performance (before and after taxes) is no guarantee of how the Fund will perform in the future.

Bar Chart [Heading]

rr_BarChartHeading

Year by Year Total Return (%) as of December 31 Each Year*

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

Best and Worst Quarterly Returns During the Period Shown in the Bar Chart Best 2nd Quarter 2020 27.28% Worst 1st Quarter 2020 -28.50%

Performance Table Heading

rr_PerformanceTableHeading

 Average Annual Total Returns After Applicable Sales Charges (for periods ended December 31, 2021)

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

The after-tax returns shown in the Average Annual Total Returns table below are calculated using the highest historical individual U.S. federal marginal income tax rates in effect during the period indicated in the table and do not reflect the impact of state, local or foreign taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

In addition, the after-tax returns shown in the table do not apply to shares held in tax-advantaged accounts such as 401(k) plans or Individual Retirement Accounts (IRAs).

Performance Table One Class of after Tax Shown [Text]

rr_PerformanceTableOneClassOfAfterTaxShown

The after-tax returns are shown only for Class Inst shares and will vary for other share classes.

Columbia Acorn International | Class A

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

5.75%

Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)

rr_MaximumDeferredSalesChargeOverOther

1.00%

^[1]

Management fees

rr_ManagementFeesOverAssets

0.79%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

0.25%

Other expenses

rr_OtherExpensesOverAssets

0.20%

Total annual Fund operating expenses

rr_ExpensesOverAssets

1.24%

^[2]

Less: Fee waivers and/or expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.01%)

^[3]

Total annual Fund operating expenses after fee waivers and/or expense reimbursements

rr_NetExpensesOverAssets

1.23%

Expenses Deferred Charges [Text Block]

rr_ExpensesDeferredChargesTextBlock

This charge is imposed on certain investments of between $1 million and $50 million redeemed within 18 months after purchase, as follows: 1.00% if redeemed within 12 months after purchase, and 0.50% if redeemed more than 12, but less than 18, months after purchase, with certain limited exceptions.

1 year

rr_ExpenseExampleYear01

$ 693

3 years

rr_ExpenseExampleYear03

945

5 years

rr_ExpenseExampleYear05

1,216

10 years

rr_ExpenseExampleYear10

1,988

1 year

rr_ExpenseExampleNoRedemptionYear01

693

3 years

rr_ExpenseExampleNoRedemptionYear03

945

5 years

rr_ExpenseExampleNoRedemptionYear05

1,216

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 1,988

1 Year

rr_AverageAnnualReturnYear01

6.17%

5 Years

rr_AverageAnnualReturnYear05

11.78%

10 Years

rr_AverageAnnualReturnYear10

8.98%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Oct. 16, 2000

Columbia Acorn International | Class C

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)

rr_MaximumDeferredSalesChargeOverOther

1.00%

^[4]

Management fees

rr_ManagementFeesOverAssets

0.79%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

1.00%

Other expenses

rr_OtherExpensesOverAssets

0.20%

Total annual Fund operating expenses

rr_ExpensesOverAssets

1.99%

^[2]

Less: Fee waivers and/or expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.01%)

^[3]

Total annual Fund operating expenses after fee waivers and/or expense reimbursements

rr_NetExpensesOverAssets

1.98%

Expenses Deferred Charges [Text Block]

rr_ExpensesDeferredChargesTextBlock

This charge applies to redemptions within 12 months after purchase, with certain limited exceptions.

1 year

rr_ExpenseExampleYear01

$ 301

3 years

rr_ExpenseExampleYear03

623

5 years

rr_ExpenseExampleYear05

1,072

10 years

rr_ExpenseExampleYear10

2,122

1 year

rr_ExpenseExampleNoRedemptionYear01

201

3 years

rr_ExpenseExampleNoRedemptionYear03

623

5 years

rr_ExpenseExampleNoRedemptionYear05

1,072

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 2,122

1 Year

rr_AverageAnnualReturnYear01

10.81%

5 Years

rr_AverageAnnualReturnYear05

12.26%

10 Years

rr_AverageAnnualReturnYear10

8.80%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Oct. 16, 2000

Columbia Acorn International | Class Inst

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)

rr_MaximumDeferredSalesChargeOverOther

none

Management fees

rr_ManagementFeesOverAssets

0.79%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.20%

Total annual Fund operating expenses

rr_ExpensesOverAssets

0.99%

^[2]

Less: Fee waivers and/or expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.01%)

^[3]

Total annual Fund operating expenses after fee waivers and/or expense reimbursements

rr_NetExpensesOverAssets

0.98%

1 year

rr_ExpenseExampleYear01

$ 100

3 years

rr_ExpenseExampleYear03

314

5 years

rr_ExpenseExampleYear05

546

10 years

rr_ExpenseExampleYear10

1,212

1 year

rr_ExpenseExampleNoRedemptionYear01

100

3 years

rr_ExpenseExampleNoRedemptionYear03

314

5 years

rr_ExpenseExampleNoRedemptionYear05

546

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 1,212

2012

rr_AnnualReturn2012

21.60%

^[5]

2013

rr_AnnualReturn2013

22.33%

^[5]

2014

rr_AnnualReturn2014

(4.28%)

^[5]

2015

rr_AnnualReturn2015

(1.33%)

^[5]

2016

rr_AnnualReturn2016

(2.28%)

^[5]

2017

rr_AnnualReturn2017

32.24%

^[5]

2018

rr_AnnualReturn2018

(15.93%)

^[5]

2019

rr_AnnualReturn2019

29.89%

^[5]

2020

rr_AnnualReturn2020

14.99%

^[5]

2021

rr_AnnualReturn2021

12.89%

^[5]

Year to Date Return, Label

rr_YearToDateReturnLabel

Year to Date return

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Mar. 31, 2022

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

(18.81%)

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2020

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

27.28%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Mar. 31, 2020

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(28.50%)

1 Year

rr_AverageAnnualReturnYear01

12.89%

5 Years

rr_AverageAnnualReturnYear05

13.39%

10 Years

rr_AverageAnnualReturnYear10

9.91%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 23, 1992

Columbia Acorn International | Class R

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)

rr_MaximumDeferredSalesChargeOverOther

none

Management fees

rr_ManagementFeesOverAssets

0.79%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

0.50%

Other expenses

rr_OtherExpensesOverAssets

0.20%

Total annual Fund operating expenses

rr_ExpensesOverAssets

1.49%

^[2]

Less: Fee waivers and/or expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.01%)

^[3]

Total annual Fund operating expenses after fee waivers and/or expense reimbursements

rr_NetExpensesOverAssets

1.48%

1 year

rr_ExpenseExampleYear01

$ 151

3 years

rr_ExpenseExampleYear03

470

5 years

rr_ExpenseExampleYear05

812

10 years

rr_ExpenseExampleYear10

1,779

1 year

rr_ExpenseExampleNoRedemptionYear01

151

3 years

rr_ExpenseExampleNoRedemptionYear03

470

5 years

rr_ExpenseExampleNoRedemptionYear05

812

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 1,779

1 Year

rr_AverageAnnualReturnYear01

12.34%

5 Years

rr_AverageAnnualReturnYear05

12.83%

10 Years

rr_AverageAnnualReturnYear10

9.29%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Aug. 02, 2011

Columbia Acorn International | Class Inst2

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)

rr_MaximumDeferredSalesChargeOverOther

none

Management fees

rr_ManagementFeesOverAssets

0.79%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.16%

Total annual Fund operating expenses

rr_ExpensesOverAssets

0.95%

^[2]

Less: Fee waivers and/or expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.03%)

^[3]

Total annual Fund operating expenses after fee waivers and/or expense reimbursements

rr_NetExpensesOverAssets

0.92%

1 year

rr_ExpenseExampleYear01

$ 94

3 years

rr_ExpenseExampleYear03

300

5 years

rr_ExpenseExampleYear05

523

10 years

rr_ExpenseExampleYear10

1,164

1 year

rr_ExpenseExampleNoRedemptionYear01

94

3 years

rr_ExpenseExampleNoRedemptionYear03

300

5 years

rr_ExpenseExampleNoRedemptionYear05

523

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 1,164

1 Year

rr_AverageAnnualReturnYear01

12.97%

5 Years

rr_AverageAnnualReturnYear05

13.46%

10 Years

rr_AverageAnnualReturnYear10

9.97%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Aug. 02, 2011

Columbia Acorn International | Class Adv

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)

rr_MaximumDeferredSalesChargeOverOther

none

Management fees

rr_ManagementFeesOverAssets

0.79%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.20%

Total annual Fund operating expenses

rr_ExpensesOverAssets

0.99%

^[2]

Less: Fee waivers and/or expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.01%)

^[3]

Total annual Fund operating expenses after fee waivers and/or expense reimbursements

rr_NetExpensesOverAssets

0.98%

1 year

rr_ExpenseExampleYear01

$ 100

3 years

rr_ExpenseExampleYear03

314

5 years

rr_ExpenseExampleYear05

546

10 years

rr_ExpenseExampleYear10

1,212

1 year

rr_ExpenseExampleNoRedemptionYear01

100

3 years

rr_ExpenseExampleNoRedemptionYear03

314

5 years

rr_ExpenseExampleNoRedemptionYear05

546

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 1,212

1 Year

rr_AverageAnnualReturnYear01

12.88%

5 Years

rr_AverageAnnualReturnYear05

13.39%

10 Years

rr_AverageAnnualReturnYear10

9.88%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Nov. 08, 2012

Columbia Acorn International | Class Inst3

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)

rr_MaximumDeferredSalesChargeOverOther

none

Management fees

rr_ManagementFeesOverAssets

0.79%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.10%

Total annual Fund operating expenses

rr_ExpensesOverAssets

0.89%

^[2]

Less: Fee waivers and/or expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.01%)

^[3]

Total annual Fund operating expenses after fee waivers and/or expense reimbursements

rr_NetExpensesOverAssets

0.88%

1 year

rr_ExpenseExampleYear01

$ 90

3 years

rr_ExpenseExampleYear03

283

5 years

rr_ExpenseExampleYear05

492

10 years

rr_ExpenseExampleYear10

1,095

1 year

rr_ExpenseExampleNoRedemptionYear01

90

3 years

rr_ExpenseExampleNoRedemptionYear03

283

5 years

rr_ExpenseExampleNoRedemptionYear05

492

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 1,095

1 Year

rr_AverageAnnualReturnYear01

13.00%

5 Years

rr_AverageAnnualReturnYear05

13.51%

10 Years

rr_AverageAnnualReturnYear10

10.01%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Nov. 08, 2012

Columbia Acorn International | returns after taxes on distributions | Class Inst

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

8.95%

5 Years

rr_AverageAnnualReturnYear05

9.65%

10 Years

rr_AverageAnnualReturnYear10

7.59%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 23, 1992

Columbia Acorn International | returns after taxes on distributions and sale of Fund shares | Class Inst

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

10.26%

5 Years

rr_AverageAnnualReturnYear05

10.03%

10 Years

rr_AverageAnnualReturnYear10

7.69%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 23, 1992

Columbia Acorn International | MSCI ACWI ex USA SMID Cap Growth Index (Net) (reflects reinvested dividends net of withholding taxes but reflects no deductions for fees, expenses or other taxes)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

8.51%

5 Years

rr_AverageAnnualReturnYear05

12.25%

10 Years

rr_AverageAnnualReturnYear10

9.34%

Columbia Acorn International | MSCI ACWI ex USA SMID Cap Index (Net) (reflects reinvested dividends net of withholding taxes but reflects no deductions for fees, expenses or other taxes)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

10.16%

5 Years

rr_AverageAnnualReturnYear05

10.30%

10 Years

rr_AverageAnnualReturnYear10

8.63%

[1] This charge is imposed on certain investments of between $1 million and $50 million redeemed within 18 months after purchase, as follows: 1.00% if redeemed within 12 months after purchase, and 0.50% if redeemed more than 12, but less than 18, months after purchase, with certain limited exceptions.

[2] “Total annual Fund operating expenses” include acquired fund fees and expenses (expenses the Fund incurs indirectly through its investments in other investment companies) and may be higher than the ratio of expenses to average net assets shown in the Financial Highlights section of this prospectus because the ratio of expenses to average net assets does not include acquired fund fees and expenses.

[3] Columbia Wanger Asset Management, LLC (the Investment Manager) has contractually agreed to waive fees and reimburse certain expenses of the Fund, through April 30, 2023, so that ordinary operating expenses (excluding transaction costs and certain other investment-related expenses, interest and fees on borrowings and expenses associated with the Fund's investment in other investment companies, if any) do not exceed the annual rates of 1.23% for Class A shares, 0.98% for Class Adv shares, 1.98% for Class C shares, 0.98% for Class Inst shares, 0.92% for Class Inst2 shares, 0.88% for Class Inst3 shares and 1.48% for Class R shares. This arrangement may only be amended or terminated with approval from the Fund's Board of Trustees and the Investment Manager. The fee waivers and/or expense reimbursements shown in the table also reflect the contractual agreement of the Fund's transfer agent, Columbia Management Investment Services Corp. (the Transfer Agent), to waive a portion of its fees through April 30, 2023, such that the Fund's transfer agency fees do not exceed the annual rates of 0.04% of the average daily net assets of Class Inst2 shares and 0.00% of the average daily net assets of Class Inst3 shares. This arrangement may be terminated at the sole discretion of the Fund's Board of Trustees.

[4] This charge applies to redemptions within 12 months after purchase, with certain limited exceptions.

[5] Year to Date return as of March 31, 2022: -18.81%

XML

Label

Element

Value

Columbia Acorn International Select

Risk/Return:

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Risk/Return [Heading]

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Summary of the Fund

Objective [Heading]

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Investment Objective

Objective, Primary [Text Block]

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Columbia Acorn International Select^SM (the Fund) seeks long-term capital appreciation.

Expense [Heading]

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Fees and Expenses of the Fund

Expense Narrative [Text Block]

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This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below. You may qualify for sales charge discounts if you and members of your immediate family invest, or agree to invest in the future, at least $50,000 in certain classes of shares of eligible funds distributed by Columbia Management Investment Distributors, Inc. (the Distributor). More information is available about these and other sales charge discounts and waivers from your financial intermediary, and can be found in the Choosing a Share Class section beginning on page 28 of the Fund’s prospectus, in Appendix A to the prospectus beginning on page A-1 and in Appendix S to the Statement of Additional Information (SAI) under Sales Charge Waivers beginning on page S-1.

Shareholder Fees Caption [Text]

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Shareholder Fees (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

April 30, 2023

Portfolio Turnover [Heading]

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Portfolio Turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The Fund may pay transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 27% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

27.00%

Expense Breakpoint Discounts [Text]

rr_ExpenseBreakpointDiscounts

You may qualify for sales charge discounts if you and members of your immediate family invest, or agree to invest in the future, at least $50,000 in certain classes of shares of eligible funds distributed by Columbia Management Investment Distributors, Inc. (the Distributor). More information is available about these and other sales charge discounts and waivers from your financial intermediary, and can be found in the Choosing a Share Class section beginning on page 28 of the Fund’s prospectus, in Appendix A to the prospectus beginning on page A-1 and in Appendix S to the Statement of Additional Information (SAI) under Sales Charge Waivers beginning on page S-1.

Expense Breakpoint, Minimum Investment Required [Amount]

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

$ 50,000

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees

“Total annual Fund operating expenses” include acquired fund fees and expenses (expenses the Fund incurs indirectly through its investments in other investment companies) and may be higher than the ratio of expenses to average net assets shown in the Financial Highlights section of this prospectus because the ratio of expenses to average net assets does not include acquired fund fees and expenses.

Expense Example [Heading]

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 Example

Expense Example Narrative [Text Block]

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The following example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example illustrates the hypothetical expenses that you would incur over the time periods indicated, and assumes that:

■ you invest $10,000 in the applicable class of Fund shares for the periods indicated,

■ your investment has a 5% return each year, and

■ the Fund’s total annual operating expenses remain the same as shown in the Annual Fund Operating Expenses table above.

Since the waivers and/or reimbursements shown in the Annual Fund Operating Expenses table above expire as indicated in the preceding table, they are only reflected in the 1 year example and the first year of the other examples. Although your actual costs may be higher or lower, based on the assumptions listed above, your costs would be:

Strategy [Heading]

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Principal Investment Strategies

Strategy Narrative [Text Block]

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Under normal circumstances, the Fund invests at least 65% of its net assets in foreign companies in developed markets (for example, Japan, Canada and the United Kingdom).

The Fund also may invest up to 35% of its total assets in companies in emerging markets (for example, China, India and Brazil). The Fund generally invests in at least three countries other than the United States but may invest up to 25% of its total assets in securities of U.S. issuers.

Under normal circumstances, the Fund invests a majority of its net assets in the common stock of small- and mid-sized companies with market capitalizations generally in the range of market capitalizations in the MSCI ACWI ex USA Growth Index (Net), the Fund's primary benchmark, (the Index) at the time of purchase (between $912.3 million and $2.3 trillion as of March 31, 2022). The market capitalization range and composition of companies in the Index are subject to change. As such, the size of the companies in which the Fund invests may change. The Fund determines a company’s market capitalization at the time of investment. As long as a majority of its net assets are invested in companies within the Index, the Fund may continue to hold and make new investments in a security even if the company’s market capitalization grows beyond the market capitalization of the largest company within the Index or falls below the market capitalization of the smallest company within the Index. 

Columbia Wanger Asset Management, LLC, the Fund's investment adviser (the Investment Manager), believes that stocks of small- and mid-sized companies, which generally are not as well known by financial analysts as larger companies, may offer higher return potential than stocks of larger companies. The Fund also may invest in larger-sized companies. The Investment Manager from time to time emphasizes one or more sectors in selecting the Fund’s investments, including the health care, industrials, and information technology sectors. 

The Fund invests in a limited number of foreign companies (generally between 30-60), offering the potential to provide above-average growth over time. In pursuit of the Fund’s objective, the portfolio managers will take advantage of the research and stock-picking capabilities of the Investment Manager and will generally concentrate the Fund’s investments in those sectors, companies, geographic regions or industries that the portfolio managers believe offer the best investment return potential. 

The Investment Manager typically seeks companies with: 

■ A strong business franchise that offers growth potential. 

■ Products and services in which the company has a competitive advantage. 

■ A stock price the Investment Manager believes is reasonable relative to the assets and earning power of the company. 

The Investment Manager may sell a portfolio holding if the security reaches the Investment Manager's price target, if the company has a deterioration of fundamentals, such as failing to meet key operating benchmarks, or if the Investment Manager believes other securities are more attractive. The Investment Manager also may sell a portfolio holding to fund redemptions. 

Risk [Heading]

rr_RiskHeading

Principal Risks

Risk Narrative [Text Block]

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An investment in the Fund involves risks, including those described below, among others. There is no assurance that the Fund will achieve its investment objective and you may lose money. The value of the Fund’s holdings may decline, and the Fund’s net asset value (NAV) and share price may go down. An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Active Management Risk. The Investment Manager’s active management of the Fund could cause the Fund to underperform its benchmark index and/or other funds with similar investment objectives and/or strategies.

Market Risk. The Fund may incur losses due to declines in the value of one or more securities in which it invests. These declines may be due to factors affecting a particular issuer, or the result of, among other things, political, regulatory, market, economic or social developments affecting the relevant market(s) more generally. In addition, turbulence in financial markets and reduced liquidity in equity, credit and/or fixed income markets may negatively affect many issuers, which could adversely affect the Fund’s ability to price or value hard-to-value assets in thinly traded and closed markets and could cause significant redemptions and operational challenges. Global economies and financial markets are increasingly interconnected, and conditions and events in one country, region or financial market may adversely impact issuers in a different country, region or financial market. These risks may be magnified if certain events or developments adversely interrupt the global supply chain; in these and other circumstances, such risks might affect companies worldwide. As a result, local, regional or global events such as terrorism, war, other conflicts, natural disasters, disease/virus outbreaks and epidemics or other public health issues, recessions, depressions or other events – or the potential for such events – could have a significant negative impact on global economic and market conditions. 

The large-scale invasion of Ukraine by Russia in February 2022 has resulted in sanctions and market disruptions including declines in regional and global stock and commodity markets and significant devaluations of Russian currency. The extent and duration of the military action are impossible to predict but could be significant. Market disruption caused by the Russian military action, and any counter measures or responses thereto (including international sanctions, a downgrade in the country’s credit rating, purchasing and financing restrictions, boycotts, tariffs, changes in consumer or purchaser preferences, cyberattacks and espionage) could have severe adverse impacts on regional and/or global securities and commodities markets, including markets for oil and natural gas. 

These impacts may include reduced market liquidity, distress in credit markets, further disruption of global supply chains, increased risk of inflation, and limited access to investments in certain international markets and/or issuers. These developments and other related events could negatively impact Fund performance. 

The pandemic caused by coronavirus disease 2019 and its variants (COVID-19) has resulted in, and may continue to result in, significant global economic and societal disruption and market volatility due to disruptions in market access, resource availability, facilities operations, imposition of tariffs, export controls and supply chain disruption, among others. Such disruptions may be caused, or exacerbated by, quarantines and travel restrictions, workforce displacement and loss in human and other resources. The uncertainty surrounding the magnitude, duration, reach, costs and effects of the global pandemic, as well as actions that have been or could be taken by governmental authorities or other third parties, present unknowns that are yet to unfold. The impacts, as well as the uncertainty over impacts to come, of COVID-19 – and any other infectious illness outbreaks, epidemics and pandemics that may arise in the future – could negatively affect global economies and markets in ways that cannot necessarily be foreseen. In addition, the impact of infectious illness outbreaks and epidemics in less developed countries may be greater due to generally less established healthcare systems, governments and financial markets. Public health crises caused by the COVID-19 outbreak may exacerbate other pre-existing political, social and economic risks in certain countries or globally. The disruptions caused by COVID-19 could prevent the Fund from executing advantageous investment decisions in a timely manner and negatively impact the Fund’s ability to achieve its investment objective. Any such events could have a significant adverse impact on the value and risk profile of the Fund. 

Sector Risk. At times, the Fund may have a significant portion of its assets invested in securities of companies conducting business within one or more economic sectors, including the health care, industrials, and information technology sectors. Companies in the same sector may be similarly affected by economic, regulatory, political or market events or conditions, which may make the Fund more vulnerable to unfavorable developments in that sector than funds that invest more broadly. Generally, the more broadly the Fund invests, the more it spreads risk and potentially reduces the risks of loss and volatility. 

■ Health Care Sector. The Fund is more susceptible to the particular risks that may affect companies in the health care sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the health care sector are subject to certain risks, including restrictions on government reimbursement for medical expenses, government approval of medical products and services, competitive pricing pressures, and the rising cost of medical products and services (especially for companies dependent upon a relatively limited number of products or services), among others. Performance of such companies may be affected by factors including, government regulation, obtaining and protecting patents (or the failure to do so), product liability and other similar litigation as well as product obsolescence. 

■ Industrials Sector. The Fund is more susceptible to the particular risks that may affect companies in the industrials sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the industrials sector are subject to certain risks, including changes in supply and demand for their specific product or service and for industrial sector products in general, including decline in demand for such products due to rapid technological developments and frequent new product introduction. Performance of such companies may be affected by factors including government regulation, world events, economic conditions and risks for environmental damage and product liability claims. 

■ Information Technology Sector. The Fund is more susceptible to the particular risks that may affect companies in the information technology sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the information technology sector are subject to certain risks, including the risk that new services, equipment or technologies will not be accepted by consumers and businesses or will become rapidly obsolete. Performance of such companies may be affected by factors including obtaining and protecting patents (or the failure to do so) and significant competitive pressures, including aggressive pricing of their products or services, new market entrants, competition for market share and short product cycles due to an accelerated rate of technological developments. Such competitive pressures may lead to limited earnings and/or falling profit margins. As a result, the value of their securities may fall or fail to rise. In addition, many information technology sector companies have limited operating histories and prices of these companies’ securities historically have been 

more volatile than other securities, especially over the short term. Some companies in the information technology sector are facing increased government and regulatory scrutiny and may be subject to adverse government or regulatory action, which could negatively impact the value of their securities. 

Select Portfolio Risk. Because the Fund may invest in a limited number of companies, the Fund as a whole is subject to greater risk of loss if any of its portfolio securities decline in price. The Fund accordingly may be more susceptible to economic, political and regulatory developments than a fund that invests in a greater number of companies. In addition, the Fund’s holdings and weightings will diverge significantly from its primary benchmark’s holdings and weightings and the Fund may therefore experience greater risk and volatility relative to the benchmark. Because the Fund may invest in more than one company concentrated in a similar industry, sector or geographic region, the Fund may be even more concentrated than the number of companies it may hold would suggest. 

Liquidity and Trading Volume Risk. Due to market conditions, including uncertainty regarding the price of a security, it may be difficult for the Fund to buy or sell portfolio securities at a desirable time or price, which could result in investment losses. This risk of portfolio illiquidity is heightened with respect to small- and mid-cap securities, generally, and foreign small- and mid-cap securities in particular. The Fund may have to lower the selling price, liquidate other investments, or forego another, more appealing investment opportunity as a result of illiquidity in the markets. The Fund may also be limited in its ability to execute favorable trades in portfolio securities in response to changes in share prices and fundamentals, and may be forced to dispose of securities under disadvantageous circumstances and at a loss. As the Fund grows in size or, conversely, if it faces significant redemption pressure, these considerations take on increasing significance and may adversely impact performance. 

Foreign Securities Risk. Investments in or exposure to securities of foreign companies may involve heightened risks relative to investments in or exposure to securities of U.S. companies. Investing in securities of foreign companies subjects the Fund to the risks associated with an issuer’s (and any of its related companies’) country of organization and places of business operations, including risks related to political, regulatory, economic, social, diplomatic and other conditions or events (including, for example, military confrontations and actions, war, other conflicts, terrorism and disease/virus outbreaks and epidemics) occurring in the country or region, as well as risks associated with less developed custody and settlement practices. Foreign securities may be more volatile and less liquid than securities of U.S. companies, and are subject to the risks associated with potential imposition of economic and other sanctions against a particular foreign country, its nationals or industries or businesses within the country. In addition, foreign governments may impose withholding or other taxes on the Fund’s income, capital gains or proceeds from the disposition of foreign securities, which could reduce the Fund’s return on such securities. 

Operational and Settlement Risks of Foreign Securities. The Fund’s foreign securities are generally held outside the United States in the primary market for the securities in the custody of foreign sub-custodians. Some countries have limited governmental oversight and regulation, which increases the risk of corruption and fraud and the possibility of losses to the Fund. In particular, under certain circumstances, foreign securities may settle on a delayed delivery basis, meaning that the Fund may be required to make payment for securities before the Fund has actually received delivery of the securities or deliver securities prior to the receipt of payment. As a result, there is a risk that the security will not be delivered to the Fund or that payment will not be received. Losses can also result from lost, stolen or counterfeit securities; defaults by brokers and banks; failures or defects of the settlement system; or poor and improper record keeping by registrars and issuers. 

Share Blocking. In certain non-U.S. markets, an issuer’s securities are blocked from trading for a specified number of days before and, in certain instances, after a shareholder meeting. The blocking period can last up to several weeks. Share blocking may prevent the Fund from buying or selling securities during this period. As a consequence of these restrictions, the Investment Manager, on behalf of the Fund, may abstain from voting proxies in markets that require share blocking. 

Emerging Market Securities Risk. Securities issued by foreign governments or companies in emerging market countries, such as China, Russia and certain countries in Eastern Europe, the Middle East, Asia, Latin America or Africa, are more likely to have greater exposure to the risks of investing in foreign securities that are described in Foreign Securities Risk. In addition, emerging market countries are more likely to experience instability resulting, for example, from rapid changes or developments in social, political, economic or other conditions. Their economies are 

usually less mature and their securities markets are typically less developed with more limited trading activity (i.e., lower trading volumes and less liquidity) than more developed countries. Emerging market securities tend to be more volatile, and may be more susceptible to market manipulation, than securities in more developed markets. Many emerging market countries are heavily dependent on international trade and have fewer trading partners, which makes them more sensitive to world commodity prices and economic downturns in other countries, and some have a higher risk of currency devaluations. Due to the differences in the nature and quality of financial information of issuers of emerging market securities, including auditing and financial reporting standards, financial information and disclosures about such issuers may be unavailable or, if made available, may be considerably less reliable than publicly available information about other foreign securities. 

Operational and Settlement Risks of Securities in Emerging Markets. Foreign sub-custodians in emerging markets may be recently organized, lack extensive operating experience or lack effective government oversight or regulation. In addition, there may be legal restrictions or limitations on the ability of the Fund to recover assets held in custody by a foreign sub-custodian in the event of the bankruptcy of the sub-custodian. There may also be a greater risk that settlement may be delayed and that cash or securities of the Fund may be lost because of failures of or defects in the system, including fraud or corruption. Settlement systems in emerging markets also have a higher risk of failed trades. 

Risks Related to Currencies and Corporate Actions in Emerging Markets. Risks related to currencies and corporate actions are also greater in emerging market countries than in developed countries. Emerging market currencies may not have an active trading market and are subject to a higher risk of currency devaluations. 

Risks Related to Corporate and Securities Laws in Emerging Markets. Securities laws in emerging markets may be relatively new and unsettled and, consequently, there is a risk of rapid and unpredictable change in laws regarding foreign investment, securities regulation, title to securities and shareholder rights. 

Small- and Mid-Cap Company Securities Risk. Investments in small- and mid-cap companies often involve greater risks than investments in larger, more established companies because small- and mid-cap companies tend to have less predictable earnings and may lack the management experience, financial resources, product diversification and competitive strengths of larger companies. Securities of small- and mid-cap companies may be less liquid and more volatile than the securities of larger companies. 

Large-Cap Company Securities Risk. Larger, more established companies may be unable to respond quickly to new competitive challenges, such as changes in consumer tastes or innovative smaller competitors. Also, large-cap companies are sometimes unable to attain the high growth rates of successful, smaller companies, especially during extended periods of economic expansion. 

Geographic Focus Risk. The Fund may be particularly susceptible to risks related to economic, political, regulatory or other events or conditions affecting issuers and countries within the specific geographic regions in which the Fund invests. The Fund’s NAV may be more volatile than the NAV of a more geographically diversified fund. 

■ Asia Pacific Region. Many of the countries in the Asia Pacific region are considered underdeveloped or developing, including from a political, economic and/or social perspective, and may have relatively unstable governments and economies based on limited business, industries and/or natural resources or commodities. Events in any one country within the region may impact other countries in the region or the region as a whole. As a result, events in the region will generally have a greater effect on the Fund than if the Fund were more geographically diversified. This could result in increased volatility in the value of the Fund’s investments and losses for the Fund. Also, securities of some companies in the region can be less liquid than U.S. or other foreign securities, potentially making it difficult for the Fund to sell such securities at a desirable time and price. 

■ Europe. The Fund is particularly susceptible to risks related to economic, political, regulatory or other events or conditions, including acts of war or other conflicts in the region, affecting issuers and countries in Europe. Countries in Europe are often closely connected and interdependent, and events in one European country can have an adverse impact on, and potentially spread to, other European countries. In addition, significant private and public sectors’ debt problems of a single European Union (EU) country can pose economic risks to the EU as a whole. As a result, the Fund’s NAV may be more volatile than the NAV of a more geographically diversified fund. If securities of issuers in Europe fall out of favor, it may cause the Fund to underperform other funds that do not 

focus their investments in this region of the world. The departure of the United Kingdom (UK) from the EU single market became effective January 1, 2021 with the end of the Brexit transition period and the post-Brexit trade deal between the UK and EU taking effect on December 31, 2020. The impact of any partial or complete dissolution of the EU on the UK and European economies and the broader global economy could be significant, resulting in negative impacts on currency and financial markets generally, such as increased volatility and illiquidity, and potentially lower economic growth in markets in Europe, which may adversely affect the value of your investment in the Fund. 

Issuer Risk. An issuer in which the Fund invests may perform poorly, and the value of its securities may therefore decline, which may negatively affect the Fund’s performance. Underperformance of an issuer may be caused by poor management decisions, competitive pressures, breakthroughs in technology, reliance on suppliers, labor problems or shortages, corporate restructurings, fraudulent disclosures, natural disasters, military confrontations and actions, war, terrorism, disease/virus outbreaks and epidemics or other events, conditions and factors. 

Foreign Currency Risk. The performance of the Fund may be materially affected positively or negatively by foreign currency strength or weakness relative to the U.S. dollar, particularly if the Fund invests a significant percentage of its assets in foreign securities or other assets denominated in currencies other than the U.S. dollar. 

Growth Securities Risk. Growth securities typically trade at a higher multiple of earnings than other types of equity securities. Accordingly, the market values of growth securities may never reach their expected market value and may decline in price. In addition, growth securities, at times, may not perform as well as value securities or the stock market in general, and may be out of favor with investors for varying periods of time. 

Risk Lose Money [Text]

rr_RiskLoseMoney

There is no assurance that the Fund will achieve its investment objective and you may lose money.

Risk Not Insured Depository Institution [Text]

rr_RiskNotInsuredDepositoryInstitution

An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Bar Chart and Performance Table [Heading]

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Performance Information

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following bar chart and table show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. The bar chart shows how the Fund’s Class Inst share performance has varied for each full calendar year shown. The table below the bar chart compares the Fund’s returns for the periods shown with those of the MSCI ACWI ex USA Growth Index (Net), the Fund's primary benchmark, and those of the MSCI ACWI ex USA Index (Net), the Fund's secondary benchmark. The MSCI ACWI ex USA Growth Index (Net) captures large- and mid-cap securities exhibiting overall growth style characteristics across 22 developed market countries and 24 emerging market countries. The MSCI ACWI ex USA Index (Net) captures large- and mid-cap representation across 22 of 23 developed market countries (excluding the United States) and 24 emerging market countries. As of March 31, 2022, the MSCI ACWI ex USA Index (Net) had 2,312 constituents and covered approximately 85% of the global equity opportunity set outside the United States. 

The performance of one or more share classes shown in the Average Annual Total Returns table below includes the Fund’s Class Inst share returns (adjusted to reflect the higher class-related operating expenses of such classes, where applicable) for periods prior to the indicated inception date of such share classes. Except for differences in fees and expenses, all share classes of the Fund would have substantially similar annual returns because all share classes of the Fund invest in the same portfolio of securities. 

The after-tax returns shown in the Average Annual Total Returns table below are calculated using the highest historical individual U.S. federal marginal income tax rates in effect during the period indicated in the table and do not reflect the impact of state, local or foreign taxes. Your actual after-tax returns will depend on your personal tax situation and may differ from those shown in the table. In addition, the after-tax returns shown in the table do not apply to shares held in tax-advantaged accounts such as 401(k) plans or Individual Retirement Accounts (IRAs). The after-tax returns are shown only for Class Inst shares and will vary for other share classes. 

The Fund’s past performance (before and after taxes) is no guarantee of how the Fund will perform in the future. Updated performance information can be obtained by calling toll-free 800.345.6611 or visiting columbiathreadneedleus.com. 

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following bar chart and table show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. The bar chart shows how the Fund’s Class Inst share performance has varied for each full calendar year shown. The table below the bar chart compares the Fund’s returns for the periods shown with those of the MSCI ACWI ex USA Growth Index (Net), the Fund's primary benchmark, and those of the MSCI ACWI ex USA Index (Net), the Fund's secondary benchmark.

Performance Availability Phone [Text]

rr_PerformanceAvailabilityPhone

800.345.6611

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

columbiathreadneedleus.com

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

The Fund’s past performance (before and after taxes) is no guarantee of how the Fund will perform in the future.

Bar Chart [Heading]

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Year by Year Total Return (%) as of December 31 Each Year*

Bar Chart Closing [Text Block]

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Best and Worst Quarterly Returns During the Period Shown in the Bar Chart Best 2nd Quarter 2020 26.16% Worst 1st Quarter 2020 -25.62%

Performance Table Heading

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 Average Annual Total Returns After Applicable Sales Charges (for periods ended December 31, 2021)

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

The after-tax returns shown in the Average Annual Total Returns table below are calculated using the highest historical individual U.S. federal marginal income tax rates in effect during the period indicated in the table and do not reflect the impact of state, local or foreign taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

In addition, the after-tax returns shown in the table do not apply to shares held in tax-advantaged accounts such as 401(k) plans or Individual Retirement Accounts (IRAs).

Performance Table One Class of after Tax Shown [Text]

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The after-tax returns are shown only for Class Inst shares and will vary for other share classes. 

Columbia Acorn International Select | Class A

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

5.75%

Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)

rr_MaximumDeferredSalesChargeOverOther

1.00%

^[1]

Management fees

rr_ManagementFeesOverAssets

0.89%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

0.25%

Other expenses

rr_OtherExpensesOverAssets

0.30%

Total annual Fund operating expenses

rr_ExpensesOverAssets

1.44%

^[2]

Less: Fee waivers and/or expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.20%)

^[3]

Total annual Fund operating expenses after fee waivers and/or expense reimbursements

rr_NetExpensesOverAssets

1.24%

Expenses Deferred Charges [Text Block]

rr_ExpensesDeferredChargesTextBlock

This charge is imposed on certain investments of between $1 million and $50 million redeemed within 18 months after purchase, as follows: 1.00% if redeemed within 12 months after purchase, and 0.50% if redeemed more than 12, but less than 18, months after purchase, with certain limited exceptions.

1 year

rr_ExpenseExampleYear01

$ 694

3 years

rr_ExpenseExampleYear03

986

5 years

rr_ExpenseExampleYear05

1,299

10 years

rr_ExpenseExampleYear10

2,184

1 year

rr_ExpenseExampleNoRedemptionYear01

694

3 years

rr_ExpenseExampleNoRedemptionYear03

986

5 years

rr_ExpenseExampleNoRedemptionYear05

1,299

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 2,184

1 Year

rr_AverageAnnualReturnYear01

4.15%

5 Years

rr_AverageAnnualReturnYear05

14.23%

10 Years

rr_AverageAnnualReturnYear10

9.66%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Oct. 16, 2000

Columbia Acorn International Select | Class C

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)

rr_MaximumDeferredSalesChargeOverOther

1.00%

^[4]

Management fees

rr_ManagementFeesOverAssets

0.89%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

1.00%

Other expenses

rr_OtherExpensesOverAssets

0.30%

Total annual Fund operating expenses

rr_ExpensesOverAssets

2.19%

^[2]

Less: Fee waivers and/or expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.20%)

^[3]

Total annual Fund operating expenses after fee waivers and/or expense reimbursements

rr_NetExpensesOverAssets

1.99%

Expenses Deferred Charges [Text Block]

rr_ExpensesDeferredChargesTextBlock

This charge applies to redemptions within 12 months after purchase, with certain limited exceptions.

1 year

rr_ExpenseExampleYear01

$ 302

3 years

rr_ExpenseExampleYear03

666

5 years

rr_ExpenseExampleYear05

1,156

10 years

rr_ExpenseExampleYear10

2,318

1 year

rr_ExpenseExampleNoRedemptionYear01

202

3 years

rr_ExpenseExampleNoRedemptionYear03

666

5 years

rr_ExpenseExampleNoRedemptionYear05

1,156

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 2,318

1 Year

rr_AverageAnnualReturnYear01

8.68%

5 Years

rr_AverageAnnualReturnYear05

14.73%

10 Years

rr_AverageAnnualReturnYear10

9.47%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Oct. 16, 2000

Columbia Acorn International Select | Class Inst

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)

rr_MaximumDeferredSalesChargeOverOther

none

Management fees

rr_ManagementFeesOverAssets

0.89%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.30%

Total annual Fund operating expenses

rr_ExpensesOverAssets

1.19%

^[2]

Less: Fee waivers and/or expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.20%)

^[3]

Total annual Fund operating expenses after fee waivers and/or expense reimbursements

rr_NetExpensesOverAssets

0.99%

1 year

rr_ExpenseExampleYear01

$ 101

3 years

rr_ExpenseExampleYear03

358

5 years

rr_ExpenseExampleYear05

635

10 years

rr_ExpenseExampleYear10

1,425

1 year

rr_ExpenseExampleNoRedemptionYear01

101

3 years

rr_ExpenseExampleNoRedemptionYear03

358

5 years

rr_ExpenseExampleNoRedemptionYear05

635

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 1,425

2012

rr_AnnualReturn2012

22.42%

^[5]

2013

rr_AnnualReturn2013

14.75%

^[5]

2014

rr_AnnualReturn2014

(6.79%)

^[5]

2015

rr_AnnualReturn2015

(1.03%)

^[5]

2016

rr_AnnualReturn2016

1.18%

^[5]

2017

rr_AnnualReturn2017

35.70%

^[5]

2018

rr_AnnualReturn2018

(12.28%)

^[5]

2019

rr_AnnualReturn2019

33.71%

^[5]

2020

rr_AnnualReturn2020

18.50%

^[5]

2021

rr_AnnualReturn2021

10.79%

^[5]

Year to Date Return, Label

rr_YearToDateReturnLabel

Year to Date return

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Mar. 31, 2022

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

(18.63%)

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2020

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

26.16%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Mar. 31, 2020

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(25.62%)

1 Year

rr_AverageAnnualReturnYear01

10.79%

5 Years

rr_AverageAnnualReturnYear05

15.88%

10 Years

rr_AverageAnnualReturnYear10

10.61%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Nov. 23, 1998

Columbia Acorn International Select | Class Adv

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)

rr_MaximumDeferredSalesChargeOverOther

none

Management fees

rr_ManagementFeesOverAssets

0.89%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.30%

Total annual Fund operating expenses

rr_ExpensesOverAssets

1.19%

^[2]

Less: Fee waivers and/or expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.20%)

^[3]

Total annual Fund operating expenses after fee waivers and/or expense reimbursements

rr_NetExpensesOverAssets

0.99%

1 year

rr_ExpenseExampleYear01

$ 101

3 years

rr_ExpenseExampleYear03

358

5 years

rr_ExpenseExampleYear05

635

10 years

rr_ExpenseExampleYear10

1,425

1 year

rr_ExpenseExampleNoRedemptionYear01

101

3 years

rr_ExpenseExampleNoRedemptionYear03

358

5 years

rr_ExpenseExampleNoRedemptionYear05

635

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 1,425

1 Year

rr_AverageAnnualReturnYear01

10.78%

5 Years

rr_AverageAnnualReturnYear05

15.89%

10 Years

rr_AverageAnnualReturnYear10

10.60%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Nov. 08, 2012

Columbia Acorn International Select | Class Inst2

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)

rr_MaximumDeferredSalesChargeOverOther

none

Management fees

rr_ManagementFeesOverAssets

0.89%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.21%

Total annual Fund operating expenses

rr_ExpensesOverAssets

1.10%

^[2]

Less: Fee waivers and/or expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.21%)

^[3]

Total annual Fund operating expenses after fee waivers and/or expense reimbursements

rr_NetExpensesOverAssets

0.89%

1 year

rr_ExpenseExampleYear01

$ 91

3 years

rr_ExpenseExampleYear03

329

5 years

rr_ExpenseExampleYear05

586

10 years

rr_ExpenseExampleYear10

1,321

1 year

rr_ExpenseExampleNoRedemptionYear01

91

3 years

rr_ExpenseExampleNoRedemptionYear03

329

5 years

rr_ExpenseExampleNoRedemptionYear05

586

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 1,321

1 Year

rr_AverageAnnualReturnYear01

10.87%

5 Years

rr_AverageAnnualReturnYear05

15.98%

10 Years

rr_AverageAnnualReturnYear10

10.67%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Nov. 08, 2012

Columbia Acorn International Select | Class Inst3

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)

rr_MaximumDeferredSalesChargeOverOther

none

Management fees

rr_ManagementFeesOverAssets

0.89%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.16%

Total annual Fund operating expenses

rr_ExpensesOverAssets

1.05%

^[2]

Less: Fee waivers and/or expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.21%)

^[3]

Total annual Fund operating expenses after fee waivers and/or expense reimbursements

rr_NetExpensesOverAssets

0.84%

1 year

rr_ExpenseExampleYear01

$ 86

3 years

rr_ExpenseExampleYear03

313

5 years

rr_ExpenseExampleYear05

559

10 years

rr_ExpenseExampleYear10

1,264

1 year

rr_ExpenseExampleNoRedemptionYear01

86

3 years

rr_ExpenseExampleNoRedemptionYear03

313

5 years

rr_ExpenseExampleNoRedemptionYear05

559

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 1,264

1 Year

rr_AverageAnnualReturnYear01

10.93%

5 Years

rr_AverageAnnualReturnYear05

16.04%

10 Years

rr_AverageAnnualReturnYear10

10.72%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Nov. 08, 2012

Columbia Acorn International Select | returns after taxes on distributions | Class Inst

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

9.52%

5 Years

rr_AverageAnnualReturnYear05

14.75%

10 Years

rr_AverageAnnualReturnYear10

9.15%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Nov. 23, 1998

Columbia Acorn International Select | returns after taxes on distributions and sale of Fund shares | Class Inst

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

7.34%

5 Years

rr_AverageAnnualReturnYear05

12.65%

10 Years

rr_AverageAnnualReturnYear10

8.33%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Nov. 23, 1998

Columbia Acorn International Select | MSCI ACWI ex USA Growth Index (Net) (reflects reinvested dividends net of withholding taxes but reflects no deductions for fees, expenses or other taxes)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

5.09%

5 Years

rr_AverageAnnualReturnYear05

13.06%

10 Years

rr_AverageAnnualReturnYear10

9.13%

Columbia Acorn International Select | MSCI ACWI ex USA Index (Net) (reflects reinvested dividends net of withholding taxes but reflects no deductions for fees, expenses or other taxes)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

7.82%

5 Years

rr_AverageAnnualReturnYear05

9.61%

10 Years

rr_AverageAnnualReturnYear10

7.28%

[1] This charge is imposed on certain investments of between $1 million and $50 million redeemed within 18 months after purchase, as follows: 1.00% if redeemed within 12 months after purchase, and 0.50% if redeemed more than 12, but less than 18, months after purchase, with certain limited exceptions.

[2] “Total annual Fund operating expenses” include acquired fund fees and expenses (expenses the Fund incurs indirectly through its investments in other investment companies) and may be higher than the ratio of expenses to average net assets shown in the Financial Highlights section of this prospectus because the ratio of expenses to average net assets does not include acquired fund fees and expenses.

[3] Columbia Wanger Asset Management, LLC (the Investment Manager) has contractually agreed to waive fees and reimburse certain expenses of the Fund, through April 30, 2023, so that ordinary operating expenses (excluding any transaction costs and certain other investment-related expenses, interest and fees on borrowings and expenses associated with the Fund’s investment in other investment companies, if any) do not exceed the annual rates of 1.24% for Class A shares, 0.99% for Class Adv shares, 1.99% for Class C shares, 0.99% for Class Inst shares, 0.89% for Class Inst2 shares and 0.84% for Class Inst3 shares. This arrangement may only be amended or terminated with approval from the Fund’s Board of Trustees and the Investment Manager.

[4] This charge applies to redemptions within 12 months after purchase, with certain limited exceptions.

[5] Year to Date return as of March 31, 2022: -18.63%

XML

Label

Element

Value

Columbia Acorn USA

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

Summary of the Fund

Objective [Heading]

rr_ObjectiveHeading

Investment Objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

Columbia Acorn USA^® (the Fund) seeks long-term capital appreciation.

Expense [Heading]

rr_ExpenseHeading

Fees and Expenses of the Fund

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below. You may qualify for sales charge discounts if you and members of your immediate family invest, or agree to invest in the future, at least $50,000 in certain classes of shares of eligible funds distributed by Columbia Management Investment Distributors, Inc. (the Distributor). More information is available about these and other sales charge discounts and waivers from your financial intermediary, and can be found in the Choosing a Share Class section beginning on page 26 of the Fund’s prospectus, in Appendix A to the prospectus beginning on page A-1 and in Appendix S to the Statement of Additional Information (SAI) under Sales Charge Waivers beginning on page S-1.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

Shareholder Fees (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

April 30, 2023

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio Turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The Fund may pay transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when Fund shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 69% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

69.00%

Expense Breakpoint Discounts [Text]

rr_ExpenseBreakpointDiscounts

You may qualify for sales charge discounts if you and members of your immediate family invest, or agree to invest in the future, at least $50,000 in certain classes of shares of eligible funds distributed by Columbia Management Investment Distributors, Inc. (the Distributor). More information is available about these and other sales charge discounts and waivers from your financial intermediary, and can be found in the Choosing a Share Class section beginning on page 26 of the Fund’s prospectus, in Appendix A to the prospectus beginning on page A-1 and in Appendix S to the Statement of Additional Information (SAI) under Sales Charge Waivers beginning on page S-1.

Expense Breakpoint, Minimum Investment Required [Amount]

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

$ 50,000

Expenses Restated to Reflect Current [Text]

rr_ExpensesRestatedToReflectCurrent

Management fees have been restated to reflect the current management fee rate.

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees

“Total annual Fund operating expenses” include acquired fund fees and expenses (expenses the Fund incurs indirectly through its investments in other investment companies) and may be higher than the ratio of expenses to average net assets shown in the Financial Highlights section of this prospectus because the ratio of expenses to average net assets does not include acquired fund fees and expenses.

Expense Example [Heading]

rr_ExpenseExampleHeading

 Example

Expense Example Narrative [Text Block]

rr_ExpenseExampleNarrativeTextBlock

The following example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example illustrates the hypothetical expenses that you would incur over the time periods indicated, and assumes that:

■ you invest $10,000 in the applicable class of Fund shares for the periods indicated,

■ your investment has a 5% return each year, and

■ the Fund’s total annual operating expenses remain the same as shown in the Annual Fund Operating Expenses table above.

Since the waivers and/or reimbursements shown in the Annual Fund Operating Expenses table above expire as indicated in the preceding table, they are only reflected in the 1 year example and the first year of the other examples. Although your actual costs may be higher or lower, based on the assumptions listed above, your costs would be:

Strategy [Heading]

rr_StrategyHeading

Principal Investment Strategies

Strategy Narrative [Text Block]

rr_StrategyNarrativeTextBlock

Under normal circumstances, the Fund invests at least 80% of its net assets (including the amount of any borrowings for investment purposes) in U.S. companies.

Under normal circumstances, the Fund invests a majority of its net assets in the common stock of small- and mid-sized companies with market capitalizations generally in the range of market capitalizations in the Russell 2500 Growth Index, the Fund's benchmark, (the Index) at the time of purchase (between $21.5 million and $30 billion as of March 31, 2022). The market capitalization range and composition of companies in the Index are subject to change. As such, the size of the companies in which the Fund invests may change. The Fund determines a company’s market capitalization at the time of investment. As long as a majority of its net assets are invested in companies within the Index, the Fund may continue to hold and make new investments in a security even if the company’s market capitalization grows beyond the market capitalization of the largest company within the Index or falls below the market capitalization of the smallest company within the Index. 

Columbia Wanger Asset Management, LLC, the Fund's investment adviser (the Investment Manager), believes that stocks of small- and mid-sized companies, which generally are not as well known by financial analysts as larger companies, may offer higher return potential than stocks of larger companies. The Fund invests the majority of its assets in U.S. companies, but also may invest up to 20% of its total assets in foreign companies in developed 

markets (for example, Japan, Canada and the United Kingdom) and in emerging markets (for example, China, India and Brazil). The Investment Manager from time to time emphasizes one or more sectors in selecting the Fund’s investments, including the consumer discretionary, health care, and information technology sectors. 

The Investment Manager typically seeks companies with: 

■ A strong business franchise that offers growth potential. 

■ Products and services in which the company has a competitive advantage. 

■ A stock price the Investment Manager believes is reasonable relative to the assets and earning power of the company. 

The Investment Manager may sell a portfolio holding if the security reaches the Investment Manager's price target, if the company has a deterioration of fundamentals, such as failing to meet key operating benchmarks, or if the Investment Manager believes other securities are more attractive. The Investment Manager also may sell a portfolio holding to fund redemptions. 

Risk [Heading]

rr_RiskHeading

Principal Risks

Risk Narrative [Text Block]

rr_RiskNarrativeTextBlock

An investment in the Fund involves risks, including those described below, among others. There is no assurance that the Fund will achieve its investment objective and you may lose money. The value of the Fund’s holdings may decline, and the Fund’s net asset value (NAV) and share price may go down. An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Active Management Risk. The Investment Manager’s active management of the Fund could cause the Fund to underperform its benchmark index and/or other funds with similar investment objectives and/or strategies.

Small- and Mid-Cap Company Securities Risk. Investments in small- and mid-cap companies often involve greater risks than investments in larger, more established companies because small- and mid-cap companies tend to have less predictable earnings and may lack the management experience, financial resources, product diversification and competitive strengths of larger companies. Securities of small- and mid-cap companies may be less liquid and more volatile than the securities of larger companies.

Market Risk. The Fund may incur losses due to declines in the value of one or more securities in which it invests. These declines may be due to factors affecting a particular issuer, or the result of, among other things, political, regulatory, market, economic or social developments affecting the relevant market(s) more generally. In addition, turbulence in financial markets and reduced liquidity in equity, credit and/or fixed income markets may negatively affect many issuers, which could adversely affect the Fund’s ability to price or value hard-to-value assets in thinly traded and closed markets and could cause significant redemptions and operational challenges. Global economies and financial markets are increasingly interconnected, and conditions and events in one country, region or financial market may adversely impact issuers in a different country, region or financial market. These risks may be magnified if certain events or developments adversely interrupt the global supply chain; in these and other circumstances, such risks might affect companies worldwide. As a result, local, regional or global events such as terrorism, war, other conflicts, natural disasters, disease/virus outbreaks and epidemics or other public health issues, recessions, depressions or other events – or the potential for such events – could have a significant negative impact on global economic and market conditions. 

The large-scale invasion of Ukraine by Russia in February 2022 has resulted in sanctions and market disruptions including declines in regional and global stock and commodity markets and significant devaluations of Russian currency. The extent and duration of the military action are impossible to predict but could be significant. Market disruption caused by the Russian military action, and any counter measures or responses thereto (including international sanctions, a downgrade in the country’s credit rating, purchasing and financing restrictions, boycotts, tariffs, changes in consumer or purchaser preferences, cyberattacks and espionage) could have severe adverse impacts on regional and/or global securities and commodities markets, including markets for oil and natural gas. These impacts may include reduced market liquidity, distress in credit markets, further disruption of global supply chains, increased risk of inflation, and limited access to investments in certain international markets and/or issuers. These developments and other related events could negatively impact Fund performance. 

The pandemic caused by coronavirus disease 2019 and its variants (COVID-19) has resulted in, and may continue to result in, significant global economic and societal disruption and market volatility due to disruptions in market access, resource availability, facilities operations, imposition of tariffs, export controls and supply chain disruption, among others. Such disruptions may be caused, or exacerbated by, quarantines and travel restrictions, workforce displacement and loss in human and other resources. The uncertainty surrounding the magnitude, duration, reach, costs and effects of the global pandemic, as well as actions that have been or could be taken by governmental authorities or other third parties, present unknowns that are yet to unfold. The impacts, as well as the uncertainty over impacts to come, of COVID-19 – and any other infectious illness outbreaks, epidemics and pandemics that may arise in the future – could negatively affect global economies and markets in ways that cannot necessarily be foreseen. In addition, the impact of infectious illness outbreaks and epidemics in less developed countries may be greater due to generally less established healthcare systems, governments and financial markets. Public health crises caused by the COVID-19 outbreak may exacerbate other pre-existing political, social and economic risks in certain countries or globally. The disruptions caused by COVID-19 could prevent the Fund from executing advantageous investment decisions in a timely manner and negatively impact the Fund’s ability to achieve its investment objective. Any such events could have a significant adverse impact on the value and risk profile of the Fund. 

Issuer Risk. An issuer in which the Fund invests may perform poorly, and the value of its securities may therefore decline, which may negatively affect the Fund’s performance. Underperformance of an issuer may be caused by poor management decisions, competitive pressures, breakthroughs in technology, reliance on suppliers, labor problems or shortages, corporate restructurings, fraudulent disclosures, natural disasters, military confrontations and actions, war, terrorism, disease/virus outbreaks and epidemics or other events, conditions and factors. 

Growth Securities Risk. Growth securities typically trade at a higher multiple of earnings than other types of equity securities. Accordingly, the market values of growth securities may never reach their expected market value and may decline in price. In addition, growth securities, at times, may not perform as well as value securities or the stock market in general, and may be out of favor with investors for varying periods of time. 

Liquidity and Trading Volume Risk. Because the Fund may invest a percentage of its assets in foreign securities, including in emerging markets, it may be subject to the liquidity and trading volume risks associated with international investing, including in emerging markets. Due to market conditions, including uncertainty regarding the price of a security, it may be difficult for the Fund to buy or sell foreign portfolio securities at a desirable time or price, which could result in investment losses and may affect the value of your investment in the Fund. This risk of portfolio illiquidity is heightened with respect to small- and mid-cap securities, generally, and foreign small- and mid-cap securities in particular. The Fund may have to lower the selling price, liquidate other investments, or forego another, more appealing investment opportunity as a result of illiquidity in the markets. The Fund may also be limited in its ability to execute favorable trades in foreign portfolio securities in response to changes in share prices and fundamentals, and may be forced to dispose of securities under disadvantageous circumstances and at a loss. As the Fund grows in size or, conversely, if it faces significant redemption pressure, these considerations take on increasing significance and may adversely impact performance. 

Sector Risk. At times, the Fund may have a significant portion of its assets invested in securities of companies conducting business within one or more economic sectors, including the consumer discretionary, health care, and information technology sectors. Companies in the same sector may be similarly affected by economic, regulatory, political or market events or conditions, which may make the Fund more vulnerable to unfavorable developments in that sector than funds that invest more broadly. Generally, the more broadly the Fund invests, the more it spreads risk and potentially reduces the risks of loss and volatility. 

■ Consumer Discretionary Sector. The Fund is more susceptible to the particular risks that may affect companies in the consumer discretionary sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the consumer discretionary sector are subject to certain risks, including fluctuations in the performance of the overall domestic and international economy, interest rate changes, increased competition and consumer confidence. Performance of such companies may be affected by factors including reduced disposable household income, reduced consumer spending, and changing demographics and consumer tastes. 

■ Health Care Sector. The Fund is more susceptible to the particular risks that may affect companies in the health care sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the health care sector are subject to certain risks, including restrictions on government reimbursement for medical expenses, government approval of medical products and services, competitive pricing pressures, and the rising cost of medical products and services (especially for companies dependent upon a relatively limited number of products or services), among others. Performance of such companies may be affected by factors including, government regulation, obtaining and protecting patents (or the failure to do so), product liability and other similar litigation as well as product obsolescence. 

■ Information Technology Sector. The Fund is more susceptible to the particular risks that may affect companies in the information technology sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the information technology sector are subject to certain risks, including the risk that new services, equipment or technologies will not be accepted by consumers and businesses or will become rapidly obsolete. Performance of such companies may be affected by factors including obtaining and protecting patents (or the failure to do so) and significant competitive pressures, including aggressive pricing of their products or services, new market entrants, competition for market share and short product cycles due to an accelerated rate of technological developments. Such competitive pressures may lead to limited earnings and/or falling profit margins. As a result, the value of their securities may fall or fail to rise. In addition, many information technology sector companies have limited operating histories and prices of these companies’ securities historically have been more volatile than other securities, especially over the short term. Some companies in the information technology sector are facing increased government and regulatory scrutiny and may be subject to adverse government or regulatory action, which could negatively impact the value of their securities. 

Foreign Securities Risk. Investments in or exposure to securities of foreign companies may involve heightened risks relative to investments in or exposure to securities of U.S. companies. Investing in securities of foreign companies subjects the Fund to the risks associated with an issuer’s (and any of its related companies’) country of organization and places of business operations, including risks related to political, regulatory, economic, social, diplomatic and other conditions or events (including, for example, military confrontations and actions, war, other conflicts, terrorism and disease/virus outbreaks and epidemics) occurring in the country or region, as well as risks associated with less developed custody and settlement practices. Foreign securities may be more volatile and less liquid than securities of U.S. companies, and are subject to the risks associated with potential imposition of economic and other sanctions against a particular foreign country, its nationals or industries or businesses within the country. In addition, foreign governments may impose withholding or other taxes on the Fund’s income, capital gains or proceeds from the disposition of foreign securities, which could reduce the Fund’s return on such securities. 

Operational and Settlement Risks of Foreign Securities. The Fund’s foreign securities are generally held outside the United States in the primary market for the securities in the custody of foreign sub-custodians. Some countries have limited governmental oversight and regulation, which increases the risk of corruption and fraud and the possibility of losses to the Fund. In particular, under certain circumstances, foreign securities may settle on a delayed delivery basis, meaning that the Fund may be required to make payment for securities before the Fund has actually received delivery of the securities or deliver securities prior to the receipt of payment. As a result, there is a risk that the security will not be delivered to the Fund or that payment will not be received. Losses can also result from lost, stolen or counterfeit securities; defaults by brokers and banks; failures or defects of the settlement system; or poor and improper record keeping by registrars and issuers. 

Share Blocking. In certain non-U.S. markets, an issuer’s securities are blocked from trading for a specified number of days before and, in certain instances, after a shareholder meeting. The blocking period can last up to several weeks. Share blocking may prevent the Fund from buying or selling securities during this period. As a consequence of these restrictions, the Investment Manager, on behalf of the Fund, may abstain from voting proxies in markets that require share blocking. 

Emerging Market Securities Risk. Securities issued by foreign governments or companies in emerging market countries are more likely to have greater exposure to the risks of investing in foreign securities that are described in Foreign Securities Risk. In addition, emerging market countries are more likely to experience instability resulting, for example, from rapid changes or developments in social, political, economic or other conditions. Their economies are 

usually less mature and their securities markets are typically less developed with more limited trading activity (i.e., lower trading volumes and less liquidity) than more developed countries. Emerging market securities tend to be more volatile, and may be more susceptible to market manipulation, than securities in more developed markets. Many emerging market countries are heavily dependent on international trade and have fewer trading partners, which makes them more sensitive to world commodity prices and economic downturns in other countries, and some have a higher risk of currency devaluations. Due to the differences in the nature and quality of financial information of issuers of emerging market securities, including auditing and financial reporting standards, financial information and disclosures about such issuers may be unavailable or, if made available, may be considerably less reliable than publicly available information about other foreign securities. 

Frequent Trading Risk. In connection with the repositioning of the Fund’s portfolio to align with the May 1, 2022 increase in the market capitalization of the companies in which the Fund may invest, the portfolio managers may more actively and frequently trade investments in the Fund's portfolio to carry out its investment strategies than they would absent the repositioning. Frequent trading of investments increases the possibility that the Fund, as relevant, will realize taxable capital gains (including short-term capital gains, which are generally taxable to shareholders at higher rates than long-term capital gains for U.S. federal income tax purposes), which could reduce the Fund's after-tax return. Frequent trading can also mean higher brokerage and other transaction costs, which could reduce the Fund's return. The trading costs and tax effects associated with portfolio turnover may adversely affect the Fund’s performance. 

Risk Lose Money [Text]

rr_RiskLoseMoney

There is no assurance that the Fund will achieve its investment objective and you may lose money.

Risk Not Insured Depository Institution [Text]

rr_RiskNotInsuredDepositoryInstitution

An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Bar Chart and Performance Table [Heading]

rr_BarChartAndPerformanceTableHeading

Performance Information

Performance Narrative [Text Block]

rr_PerformanceNarrativeTextBlock

The following bar chart and table show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. The bar chart shows how the Fund’s Class Inst share performance has varied for each full calendar year shown. The table below the bar chart compares the Fund’s returns for the periods shown with the Russell 2500 Growth Index.

Effective May 1, 2022, the Fund compares its performance to that of the Russell 2500 Growth Index (the New Index). Prior to this date, the Fund compared its performance to that of the Russell 2000 Growth Index (the Former Index). The Fund changed its primary benchmark in connection with changes to its principal investment strategies that became effective May 1, 2022. The Investment Manager believes that the New Index provides a more appropriate comparison than the Former Index for investors measuring the Fund's relative performance. Information on the Former Index will be shown for a one-year transition period. 

The performance of one or more share classes shown in the Average Annual Total Returns table below includes the Fund’s Class Inst share returns (adjusted to reflect the higher class-related operating expenses of such classes, where applicable) for periods prior to the indicated inception date of such share classes. Except for differences in fees and expenses, all share classes of the Fund would have substantially similar annual returns because all share classes of the Fund invest in the same portfolio of securities. 

The after-tax returns shown in the Average Annual Total Returns table below are calculated using the highest historical individual U.S. federal marginal income tax rates in effect during the period indicated in the table and do not reflect the impact of state, local or foreign taxes. Your actual after-tax returns will depend on your personal tax situation and may differ from those shown in the table. In addition, the after-tax returns shown in the table do not apply to shares held in tax-advantaged accounts such as 401(k) plans or Individual Retirement Accounts (IRAs). The after-tax returns are shown only for Class Inst shares and will vary for other share classes. Returns after taxes on distributions and sale of Fund shares are higher than before-tax returns for certain periods shown because they reflect the tax benefit of capital losses realized on the redemption of Fund shares. 

The Fund’s performance prior to May 1, 2022 reflects returns achieved pursuant to a strategy with a different market capitalization limit on the companies in which the Fund invests a majority of its assets. If the Fund's current strategies had been in place for the prior periods, results shown would have been different. 

The Fund’s past performance (before and after taxes) is no guarantee of how the Fund will perform in the future. Updated performance information can be obtained by calling toll-free 800.345.6611 or visiting columbiathreadneedleus.com. 

Performance Information Illustrates Variability of Returns [Text]

rr_PerformanceInformationIllustratesVariabilityOfReturns

The following bar chart and table show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. The bar chart shows how the Fund’s Class Inst share performance has varied for each full calendar year shown. The table below the bar chart compares the Fund’s returns for the periods shown with the Russell 2500 Growth Index.

Performance Availability Phone [Text]

rr_PerformanceAvailabilityPhone

800.345.6611

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

columbiathreadneedleus.com

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

The Fund’s past performance (before and after taxes) is no guarantee of how the Fund will perform in the future.

Bar Chart [Heading]

rr_BarChartHeading

Year by Year Total Return (%) as of December 31 Each Year*

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

Best and Worst Quarterly Returns During the Period Shown in the Bar Chart Best 2nd Quarter 2020 26.69% Worst 1st Quarter 2020 -27.03%

Performance Table Heading

rr_PerformanceTableHeading

 Average Annual Total Returns After Applicable Sales Charges (for periods ended December 31, 2021)

Performance Table Market Index Changed

rr_PerformanceTableMarketIndexChanged

Effective May 1, 2022, the Fund compares its performance to that of the Russell 2500 Growth Index (the New Index). Prior to this date, the Fund compared its performance to that of the Russell 2000 Growth Index (the Former Index). The Fund changed its primary benchmark in connection with changes to its principal investment strategies that became effective May 1, 2022. The Investment Manager believes that the New Index provides a more appropriate comparison than the Former Index for investors measuring the Fund's relative performance. Information on the Former Index will be shown for a one-year transition period. 

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

The after-tax returns shown in the Average Annual Total Returns table below are calculated using the highest historical individual U.S. federal marginal income tax rates in effect during the period indicated in the table and do not reflect the impact of state, local or foreign taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

In addition, the after-tax returns shown in the table do not apply to shares held in tax-advantaged accounts such as 401(k) plans or Individual Retirement Accounts (IRAs).

Performance Table One Class of after Tax Shown [Text]

rr_PerformanceTableOneClassOfAfterTaxShown

The after-tax returns are shown only for Class Inst shares and will vary for other share classes.

Performance Table Explanation after Tax Higher

rr_PerformanceTableExplanationAfterTaxHigher

Returns after taxes on distributions and sale of Fund shares are higher than before-tax returns for certain periods shown because they reflect the tax benefit of capital losses realized on the redemption of Fund shares. 

Columbia Acorn USA | Class A

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

5.75%

Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)

rr_MaximumDeferredSalesChargeOverOther

1.00%

^[1]

Management fees

rr_ManagementFeesOverAssets

0.74%

^[2]

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

0.25%

Other expenses

rr_OtherExpensesOverAssets

0.23%

Total annual Fund operating expenses

rr_ExpensesOverAssets

1.22%

^[3]

Less: Fee waivers and/or expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.14%)

^[4]

Total annual Fund operating expenses after fee waivers and/or expense reimbursements

rr_NetExpensesOverAssets

1.08%

Expenses Deferred Charges [Text Block]

rr_ExpensesDeferredChargesTextBlock

This charge is imposed on certain investments of between $1 million and $50 million redeemed within 18 months after purchase, as follows: 1.00% if redeemed within 12 months after purchase, and 0.50% if redeemed more than 12, but less than 18, months after purchase, with certain limited exceptions.

1 year

rr_ExpenseExampleYear01

$ 679

3 years

rr_ExpenseExampleYear03

927

5 years

rr_ExpenseExampleYear05

1,194

10 years

rr_ExpenseExampleYear10

1,956

1 year

rr_ExpenseExampleNoRedemptionYear01

679

3 years

rr_ExpenseExampleNoRedemptionYear03

927

5 years

rr_ExpenseExampleNoRedemptionYear05

1,194

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 1,956

1 Year

rr_AverageAnnualReturnYear01

2.48%

5 Years

rr_AverageAnnualReturnYear05

14.11%

10 Years

rr_AverageAnnualReturnYear10

13.29%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Oct. 16, 2000

Columbia Acorn USA | Class C

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)

rr_MaximumDeferredSalesChargeOverOther

1.00%

^[5]

Management fees

rr_ManagementFeesOverAssets

0.74%

^[2]

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

1.00%

Other expenses

rr_OtherExpensesOverAssets

0.23%

Total annual Fund operating expenses

rr_ExpensesOverAssets

1.97%

^[3]

Less: Fee waivers and/or expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.14%)

^[4]

Total annual Fund operating expenses after fee waivers and/or expense reimbursements

rr_NetExpensesOverAssets

1.83%

Expenses Deferred Charges [Text Block]

rr_ExpensesDeferredChargesTextBlock

This charge applies to redemptions within 12 months after purchase, with certain limited exceptions.

1 year

rr_ExpenseExampleYear01

$ 286

3 years

rr_ExpenseExampleYear03

605

5 years

rr_ExpenseExampleYear05

1,049

10 years

rr_ExpenseExampleYear10

2,090

1 year

rr_ExpenseExampleNoRedemptionYear01

186

3 years

rr_ExpenseExampleNoRedemptionYear03

605

5 years

rr_ExpenseExampleNoRedemptionYear05

1,049

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 2,090

1 Year

rr_AverageAnnualReturnYear01

7.02%

5 Years

rr_AverageAnnualReturnYear05

14.59%

10 Years

rr_AverageAnnualReturnYear10

13.14%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Oct. 16, 2000

Columbia Acorn USA | Class Inst

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)

rr_MaximumDeferredSalesChargeOverOther

none

Management fees

rr_ManagementFeesOverAssets

0.74%

^[2]

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.23%

Total annual Fund operating expenses

rr_ExpensesOverAssets

0.97%

^[3]

Less: Fee waivers and/or expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.14%)

^[4]

Total annual Fund operating expenses after fee waivers and/or expense reimbursements

rr_NetExpensesOverAssets

0.83%

1 year

rr_ExpenseExampleYear01

$ 85

3 years

rr_ExpenseExampleYear03

295

5 years

rr_ExpenseExampleYear05

523

10 years

rr_ExpenseExampleYear10

1,177

1 year

rr_ExpenseExampleNoRedemptionYear01

85

3 years

rr_ExpenseExampleNoRedemptionYear03

295

5 years

rr_ExpenseExampleNoRedemptionYear05

523

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 1,177

2012

rr_AnnualReturn2012

18.98%

^[6]

2013

rr_AnnualReturn2013

32.72%

^[6]

2014

rr_AnnualReturn2014

3.61%

^[6]

2015

rr_AnnualReturn2015

(1.36%)

^[6]

2016

rr_AnnualReturn2016

13.00%

^[6]

2017

rr_AnnualReturn2017

19.44%

^[6]

2018

rr_AnnualReturn2018

(1.98%)

^[6]

2019

rr_AnnualReturn2019

31.28%

^[6]

2020

rr_AnnualReturn2020

24.04%

^[6]

2021

rr_AnnualReturn2021

8.95%

^[6]

Year to Date Return, Label

rr_YearToDateReturnLabel

Year to Date return

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Mar. 31, 2022

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

(16.59%)

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2020

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

26.69%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Mar. 31, 2020

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(27.03%)

1 Year

rr_AverageAnnualReturnYear01

8.95%

5 Years

rr_AverageAnnualReturnYear05

15.74%

10 Years

rr_AverageAnnualReturnYear10

14.24%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 04, 1996

Columbia Acorn USA | Class Adv

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)

rr_MaximumDeferredSalesChargeOverOther

none

Management fees

rr_ManagementFeesOverAssets

0.74%

^[2]

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.23%

Total annual Fund operating expenses

rr_ExpensesOverAssets

0.97%

^[3]

Less: Fee waivers and/or expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.14%)

^[4]

Total annual Fund operating expenses after fee waivers and/or expense reimbursements

rr_NetExpensesOverAssets

0.83%

1 year

rr_ExpenseExampleYear01

$ 85

3 years

rr_ExpenseExampleYear03

295

5 years

rr_ExpenseExampleYear05

523

10 years

rr_ExpenseExampleYear10

1,177

1 year

rr_ExpenseExampleNoRedemptionYear01

85

3 years

rr_ExpenseExampleNoRedemptionYear03

295

5 years

rr_ExpenseExampleNoRedemptionYear05

523

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 1,177

1 Year

rr_AverageAnnualReturnYear01

8.92%

5 Years

rr_AverageAnnualReturnYear05

15.75%

10 Years

rr_AverageAnnualReturnYear10

14.25%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Nov. 08, 2012

Columbia Acorn USA | Class Inst2

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)

rr_MaximumDeferredSalesChargeOverOther

none

Management fees

rr_ManagementFeesOverAssets

0.74%

^[2]

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.19%

Total annual Fund operating expenses

rr_ExpensesOverAssets

0.93%

^[3]

Less: Fee waivers and/or expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.12%)

^[4]

Total annual Fund operating expenses after fee waivers and/or expense reimbursements

rr_NetExpensesOverAssets

0.81%

1 year

rr_ExpenseExampleYear01

$ 83

3 years

rr_ExpenseExampleYear03

284

5 years

rr_ExpenseExampleYear05

503

10 years

rr_ExpenseExampleYear10

1,132

1 year

rr_ExpenseExampleNoRedemptionYear01

83

3 years

rr_ExpenseExampleNoRedemptionYear03

284

5 years

rr_ExpenseExampleNoRedemptionYear05

503

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 1,132

1 Year

rr_AverageAnnualReturnYear01

8.99%

5 Years

rr_AverageAnnualReturnYear05

15.83%

10 Years

rr_AverageAnnualReturnYear10

14.33%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Nov. 08, 2012

Columbia Acorn USA | Class Inst3

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)

rr_MaximumDeferredSalesChargeOverOther

none

Management fees

rr_ManagementFeesOverAssets

0.74%

^[2]

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.13%

Total annual Fund operating expenses

rr_ExpensesOverAssets

0.87%

^[3]

Less: Fee waivers and/or expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.11%)

^[4]

Total annual Fund operating expenses after fee waivers and/or expense reimbursements

rr_NetExpensesOverAssets

0.76%

1 year

rr_ExpenseExampleYear01

$ 78

3 years

rr_ExpenseExampleYear03

267

5 years

rr_ExpenseExampleYear05

471

10 years

rr_ExpenseExampleYear10

1,062

1 year

rr_ExpenseExampleNoRedemptionYear01

78

3 years

rr_ExpenseExampleNoRedemptionYear03

267

5 years

rr_ExpenseExampleNoRedemptionYear05

471

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 1,062

1 Year

rr_AverageAnnualReturnYear01

9.09%

5 Years

rr_AverageAnnualReturnYear05

15.88%

10 Years

rr_AverageAnnualReturnYear10

14.38%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Nov. 08, 2012

Columbia Acorn USA | returns after taxes on distributions | Class Inst

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

2.33%

5 Years

rr_AverageAnnualReturnYear05

11.04%

10 Years

rr_AverageAnnualReturnYear10

9.41%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 04, 1996

Columbia Acorn USA | returns after taxes on distributions and sale of Fund shares | Class Inst

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

9.25%

5 Years

rr_AverageAnnualReturnYear05

11.47%

10 Years

rr_AverageAnnualReturnYear10

10.27%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 04, 1996

Columbia Acorn USA | Russell 2500 Growth Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

5.04%

5 Years

rr_AverageAnnualReturnYear05

17.65%

10 Years

rr_AverageAnnualReturnYear10

15.75%

Columbia Acorn USA | Russell 2000 Growth Index (reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

2.83%

5 Years

rr_AverageAnnualReturnYear05

14.53%

10 Years

rr_AverageAnnualReturnYear10

14.14%

[1] This charge is imposed on certain investments of between $1 million and $50 million redeemed within 18 months after purchase, as follows: 1.00% if redeemed within 12 months after purchase, and 0.50% if redeemed more than 12, but less than 18, months after purchase, with certain limited exceptions.

[2] Management fees have been restated to reflect the current management fee rate.

[3] “Total annual Fund operating expenses” include acquired fund fees and expenses (expenses the Fund incurs indirectly through its investments in other investment companies) and may be higher than the ratio of expenses to average net assets shown in the Financial Highlights section of this prospectus because the ratio of expenses to average net assets does not include acquired fund fees and expenses.

[4] Columbia Wanger Asset Management, LLC (the Investment Manager) has contractually agreed to waive fees and reimburse certain expenses of the Fund, through April 30, 2023, so that ordinary operating expenses (excluding transaction costs and certain other investment-related expenses, interest and fees on borrowings and expenses associated with the Fund’s investment in other investment companies, if any) do not exceed the annual rates of 1.08% for Class A shares, 0.83% for Class Adv shares, 1.83% for Class C shares, 0.83% for Class Inst shares, 0.81% for Class Inst2 shares and 0.76% for Class Inst3 shares. This arrangement may only be amended or terminated with approval from the Fund’s Board of Trustees and the Investment Manager. The fee waivers and/or expense reimbursements shown in the table also reflect the contractual agreement of the Fund’s transfer agent, Columbia Management Investment Services Corp. (the Transfer Agent), to waive a portion of its fees through April 30, 2023, such that the Fund’s transfer agency fees do not exceed the annual rate of 0.08% of the average daily net assets of each share class other than Class Inst2 and Class Inst3. This arrangement may be terminated at the sole discretion of the Fund’s Board of Trustees.

[5] This charge applies to redemptions within 12 months after purchase, with certain limited exceptions.

[6] Year to Date return as of March 31, 2022: -16.59%

XML

Label

Element

Value

Columbia Thermostat Fund

Risk/Return:

rr_RiskReturnAbstract

Risk/Return [Heading]

rr_RiskReturnHeading

Summary of the Fund

Objective [Heading]

rr_ObjectiveHeading

Investment Objective

Objective, Primary [Text Block]

rr_ObjectivePrimaryTextBlock

Columbia Thermostat Fund^SM (the Fund) seeks long-term capital appreciation.

Expense [Heading]

rr_ExpenseHeading

Fees and Expenses of the Fund

Expense Narrative [Text Block]

rr_ExpenseNarrativeTextBlock

This table describes the fees and expenses that you may pay if you buy, hold and sell shares of the Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below. You may qualify for sales charge discounts if you and members of your immediate family invest, or agree to invest in the future, at least $50,000 in certain classes of shares of eligible funds distributed by Columbia Management Investment Distributors, Inc. (the Distributor). More information is available about these and other sales charge discounts and waivers from your financial intermediary, and can be found in the Choosing a Share Class section beginning on page 49 of the Fund’s prospectus, in Appendix A to the prospectus beginning on page A-1 and in Appendix S to the Statement of Additional Information (SAI) under Sales Charge Waivers beginning on page S-1.

Shareholder Fees Caption [Text]

rr_ShareholderFeesCaption

Shareholder Fees (fees paid directly from your investment)

Operating Expenses Caption [Text]

rr_OperatingExpensesCaption

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Fee Waiver or Reimbursement over Assets, Date of Termination

rr_FeeWaiverOrReimbursementOverAssetsDateOfTermination

April 30, 2023

Portfolio Turnover [Heading]

rr_PortfolioTurnoverHeading

Portfolio Turnover

Portfolio Turnover [Text Block]

rr_PortfolioTurnoverTextBlock

The Fund will indirectly bear the expenses associated with portfolio turnover of the underlying Portfolio Funds in which the Fund invests. Each Portfolio Fund pays transaction costs, such as commissions, when it buys and sells securities (or “turns over” its portfolio). A Portfolio Fund’s higher portfolio turnover rate may indicate higher transaction costs and may result in higher taxes when its shares are held in a taxable account. These costs, which are not reflected in annual fund operating expenses or in the example, affect the Fund’s performance. During the most recent fiscal year, the Fund’s portfolio turnover rate was 49% of the average value of its portfolio.

Portfolio Turnover, Rate

rr_PortfolioTurnoverRate

49.00%

Expense Breakpoint Discounts [Text]

rr_ExpenseBreakpointDiscounts

You may qualify for sales charge discounts if you and members of your immediate family invest, or agree to invest in the future, at least $50,000 in certain classes of shares of eligible funds distributed by Columbia Management Investment Distributors, Inc. (the Distributor). More information is available about these and other sales charge discounts and waivers from your financial intermediary, and can be found in the Choosing a Share Class section beginning on page 49 of the Fund’s prospectus, in Appendix A to the prospectus beginning on page A-1 and in Appendix S to the Statement of Additional Information (SAI) under Sales Charge Waivers beginning on page S-1.

Expense Breakpoint, Minimum Investment Required [Amount]

rr_ExpenseBreakpointMinimumInvestmentRequiredAmount

$ 50,000

Expenses Not Correlated to Ratio Due to Acquired Fund Fees [Text]

rr_ExpensesNotCorrelatedToRatioDueToAcquiredFundFees

“Total annual Fund operating expenses” include acquired fund (Portfolio Fund) fees and expenses (expenses the Fund incurs indirectly through its investments in other funds) and may be higher than the ratio of expenses to average net assets shown in the Financial Highlights section of this prospectus because the ratio of expenses to average net assets does not include Portfolio Fund (acquired fund) fees and expenses.

Expense Example [Heading]

rr_ExpenseExampleHeading

 Example

Expense Example Narrative [Text Block]

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The following example is intended to help you compare the cost of investing in the Fund with the cost of investing in other mutual funds. The example illustrates the hypothetical expenses that you would incur over the time periods indicated, and assumes that:

■ you invest $10,000 in the applicable class of Fund shares for the periods indicated,

■ your investment has a 5% return each year, and

■ the Fund’s total annual operating expenses remain the same as shown in the Annual Fund Operating Expenses table above.

Since the waivers and/or reimbursements shown in the Annual Fund Operating Expenses table above expire as indicated in the preceding table, they are only reflected in the 1 year example and the first year of the other examples. Although your actual costs may be higher or lower, based on the assumptions listed above, your costs would be:

Strategy [Heading]

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Principal Investment Strategies

Strategy Narrative [Text Block]

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The Fund is primarily managed as a fund that invests in other funds (i.e., a “fund-of-funds”) that seeks to achieve its investment objective by investing its assets among a selected group of underlying stock and bond mutual funds and exchanged-traded funds (ETFs) for which Columbia Wanger Asset Management, LLC, the Fund’s investment adviser (the Investment Manager) or its affiliates, including Columbia Management Investment Advisers, LLC (Columbia Management), serves as investment adviser or principal underwriter (the Portfolio Funds). Under normal circumstances, the Fund allocates at least 95% of its net assets (stock/bond assets) among the Portfolio Funds according to an asset allocation table based on the current level of the Standard & Poor’s (S&P) 500^® Index.

Generally, the Fund’s allocation to stock funds increases as the S&P 500^® Index declines and decreases as the S&P 500^® Index rises. When the S&P 500^® Index goes up in relation to trading range bands that are predetermined by the Investment Manager, the Fund sells a portion of its stock Portfolio Funds and invests more in the bond Portfolio Funds, and when the S&P 500^® Index goes down in relation to the predetermined bands, the Fund increases its investment in the stock Portfolio Funds. Under normal circumstances, the Fund may invest up to 5% of net assets plus any cash received that day in cash, high quality short-term paper and government securities.

Although many asset allocation funds follow a basic approach of moving assets from stocks to bonds when the equity market goes up, and from bonds to stocks when the equity market goes down, some are run by investment managers who allocate fund assets by making subjective decisions based on complicated economic and financial models and complex graphs of market behavior. By contrast, the day-to-day investment decisions for the Fund are made according to a single predetermined allocation table set forth below. The temperature in your house is run by a single rule: your thermostat turns on the furnace if your house is too cold or turns on the air conditioner if your house is too warm. This Fund works the same way, so it is named Columbia Thermostat Fund.

Just as a thermostat may be set at different ranges for different seasons, the structure and allocation ranges of the Fund’s asset allocation table may be changed from time to time between two forms, based on the Investment Manager’s determination of whether it expects the equity market to be moving over the next year in a side-ways or non-directional pattern, which the Investment Manager terms an “expensive” market, or to be trending upward, which the Investment Manager terms a “normal” market. The Investment Manager’s process and methodology for determining whether the current market is “expensive” or “normal” and the structure of each form of allocation table are described in more detail below under Determination of Current Market State. Such determination will be made on at least an annual basis and will be reflected in the asset allocation table disclosed in this prospectus. In general, the two different forms of allocation table are intended to maximize the capture of value under the two different sets of market conditions.

The Fund’s current asset allocation table, which is set forth below, has been in place since May 1, 2021 and reflects the Investment Manager’s determination that the equity market is currently “expensive.” This structure of the Fund’s current asset allocation table reflects the same form that was in place from the Fund’s inception in 2002 through April 30, 2020. From May 1, 2020 through April 30, 2021, the asset allocation table in place for the Fund reflected the Investment Manager’s determination that the equity market was “normal.” The asset allocation table is updated at least annually to reflect the median historical information used in the table, and the resulting S&P 500^® Index levels used to create the bands around the median, regardless of the market state.

Stock/Bond Allocation Table
	How the Fund will Invest the Stock/Bond Assets
Level of the S&P 500® Index	Stock Percentage	Bond Percentage
over 4239	10%	90%
over 4076 – 4239	15%	85%
over 3919 – 4076	20%	80%
over 3768 – 3919	25%	75%
over 3623 – 3768	30%	70%
over 3484 – 3623	35%	65%
over 3350 – 3484	40%	60%
over 3221 – 3350	45%	55%
over 3095 – 3221	50%	50%
over 2971 – 3095	55%	45%
over 2852 – 2971	60%	40%
over 2738 – 2852	65%	35%
over 2628 – 2738	70%	30%
over 2523 – 2628	75%	25%
over 2422 – 2523	80%	20%
over 2325 – 2422	85%	15%
2325 and under	90%	10%

When the S&P 500^® Index moves into a new band on the table, the Fund will rebalance the stock/bond mix to reflect the new S&P 500^® Index price level by redeeming shares of some Portfolio Funds and purchasing shares of other Portfolio Funds. Any such rebalancing typically will be implemented promptly. However, there are two circumstances when a rebalancing may be implemented over a longer timeline. First, when a rebalancing or allocation table change would trigger a 10% point or greater change in stock and bond allocations or individual Portfolio Funds, the rebalancing may be implemented over a period of up to two weeks, if deemed by the Investment Manager to be in the best interest of shareholders. The second exception is a “31-day Rule;” in order to reduce taxable events and minimize short-term trading if the S&P 500^® Index price moves back and forth across a band in the allocation table,

after the Fund has increased its percentage allocation to either stock funds or bond funds, it will not decrease that allocation for at least 31 days. Following a change in the Fund’s stock/bond mix, if the S&P 500^® Index remains within the same band for a while, normal market fluctuations will change the values of the Fund’s holdings of stock Portfolio Funds and bond Portfolio Funds. The Investment Manager will invest cash flows from sales (or redemptions) of Fund shares to bring the stock/bond mix back toward the allocation percentages for that S&P 500^® Index band. For example, if the S&P 500^® Index is in the 2628 band, and the value of the holdings of the stock Portfolio Funds has dropped to 68% of the value of the holdings of all Portfolio Funds, the Investment Manager would invest new cash in the stock Portfolio Funds (or cash for redemptions would come from the bond Portfolio Funds) to restore the 70% stock allocation. If the 31-day Rule is in effect, the Investment Manager will invest new cash at the stock/bond percentage allocation as of the latest rebalancing.

As another illustrative example, suppose the following:

Date	Level of the S&P 500® Index	How the Fund will invest the Stock/ Bond Assets(1)
Nov. 1	We begin when the market is 3200	50% stocks, 50% bonds
Dec. 1	The S&P 500® goes to 3300	rebalance 45% stocks, 55% bonds
Dec. 6	The S&P 500® drops back to 3180	no reversal for 31 days
Jan. 2	The S&P 500® is at 3150	rebalance 50% stocks, 50% bonds
Jan. 20	The S&P 500 drops to 3000	rebalance 55% stocks, 45% bonds(2)
Jan. 30	The S&P 500® goes to 3125	no reversal for 31 days
Feb. 20	The S&P 500® is at 3130	rebalance 50% stocks, 50% bonds

⁽¹⁾ For each rebalancing the Fund will trade the underlying stock and bond Portfolio Funds on the next business day.

⁽²⁾ The market has made a continuation move by going through a second action level, not a reversal move, so the 31-day Rule does not apply in this case.

The Investment Manager chooses the Portfolio Funds to be generally consistent with the composition of the Fund’s primary stock and bond benchmarks and to allow the Fund to participate in strategies the Investment Manager believes can provide additional return due to active management.

The following table shows the stock and bond Portfolio Funds that the Fund currently uses in its “fund-of-funds” structure and the current target percentage for each Portfolio Fund within the stock or bond asset class. As described more fully below, the Investment Manager may substitute or add additional Portfolio Funds at any time, including funds introduced after the date of this prospectus. The target percentage within each asset class category is achieved by rebalancing the investments within the asset class whenever the S&P 500^® Index moves into a new band on the allocation table, subject to the 31-day Rule described above. The Fund will not liquidate its investment in one Portfolio Fund in order to invest in another Portfolio Fund except in connection with a rebalancing due to a move of the S&P 500^® Index into a new band (or due to a change by the Investment Manager in the Portfolio Funds or to the relative target percentages among them). Until a subsequent rebalancing, the Fund’s cash flows are invested in, or redeemed from, the Portfolio Funds in a manner that will reduce any deviation of the relative values of the Fund’s holdings of the Portfolio Funds from the percentages shown below.

Allocation of Stock/Bond Assets Within Asset Classes
Stock Funds	Type of Fund	Allocation
Columbia Acorn® Fund	Small/Mid-cap growth	10%
Columbia Contrarian Core Fund	Large-cap blend	15%
Columbia Emerging Markets Fund	International core	10%
Columbia Large Cap Enhanced Core Fund	Large-cap blend	15%
Columbia Large Cap Index Fund	Large-cap blend	30%
Columbia Research Enhanced Core ETF	Beta Advantage® U.S. equity	10%
Columbia Select Mid Cap Value Fund	Mid-cap value	10%

Allocation of Stock/Bond Assets Within Asset Classes
Total		100%
Bond Funds	Type of Fund	Allocation
Columbia Corporate Income Fund	Corporate bond	10%
Columbia Diversified Fixed Income Allocation ETF	Beta Advantage® multi-sector bond	10%
Columbia Quality Income Fund	Government bond	20%
Columbia Short Term Bond Fund	Short term bond	15%
Columbia Total Return Bond Fund	Intermediate core bond	10%
Columbia U.S. Treasury Index Fund	U.S. Treasury notes/bonds	35%
Total		100%

See the Portfolio Funds Summary section of this prospectus for information about the Portfolio Funds’ investment objectives and principal investment strategies. Each of the Portfolio Funds is managed by the Investment Manager or its affiliates. The Fund does not pay any sales load on its purchases of shares of the Portfolio Funds.

The Investment Manager has the authority to review the Portfolio Funds and to change the relative percentages among them or to add or eliminate funds. Such review will occur on at least an annual basis and will be reflected in the Portfolio Funds table disclosed in this prospectus.

Determination of Current Market State

Just as a thermostat may be set at different ranges for different seasons, the Fund’s allocation of assets between stock and bond funds is expected to be set at different range bands depending principally on the Investment Manager’s view of how expensive the equity market is compared to historical levels.

At least annually, the Investment Manager will conduct a review of the current equity market price levels compared to historical price levels, and will determine if the equity market is in an “expensive” state, or a “normal” state. This review will begin with a comparison of the S&P 500^® Index’s cyclically adjusted price-to-earnings ratio for the prior seven years against a 40-year history, but the Investment Manager will also take into account additional quantitative or qualitative market factors, including for example, trends in equity price measures and comparisons of equity prices against prices for other asset classes. Based on its determination of the current market state, the Investment Manager will select the form of allocation table to be effective in the Fund’s current prospectus. Also as part of this review, the Investment Manager will update the median historical information used in the table, and the resulting S&P 500^® Index levels used to create the bands around the median, regardless of the market state.

As noted below, the form of table used for an “expensive” market is expected to be different from that used for a “normal” market.

Generally, the Investment Manager will determine the current state of the equity market to be “expensive” when its analysis of the S&P 500^® Index’s cyclically adjusted price-to-earnings ratio for the prior seven years is within the top quartile of ratio observations over a 40-year history. The “expensive” equity market form of allocation table for the Fund is structured around an implied S&P 500^® Index trading range median of 50% stocks/50% bonds (the 50/50 Band), with allocations to bonds decreasing through stratified range bands below the 50/50 Band and allocations to bonds increasing through stratified range bands above the 50/50 Band, as shown by the following example:

“Expensive” Equity Market Form of Stock/Bond Allocation Table
Level of the S&P 500® Index	Stock Percentage	Bond Percentage
above top of trading range below	10%	90%
4% trading range above top of range below	15%	85%
4% trading range above top of range below	20%	80%
4% trading range above top of range below	25%	75%
4% trading range above top of range below	30%	70%

“Expensive” Equity Market Form of Stock/Bond Allocation Table
Level of the S&P 500® Index	Stock Percentage	Bond Percentage
4% trading range above top of range below	35%	65%
4% trading range above top of range below	40%	60%
4% trading range above top of range below	45%	55%
4% trading range centered on implied median (50/50 Band)*	50%	50%
4% trading range below bottom of range above	55%	45%
4% trading range below bottom of range above	60%	40%
4% trading range below bottom of range above	65%	35%
4% trading range below bottom of range above	70%	30%
4% trading range below bottom of range above	75%	25%
4% trading range below bottom of range above	80%	20%
4% trading range below bottom of range above	85%	15%
below bottom of trading range above	90%	10%

*Implied median price level as calculated by the Investment Manager.

The “expensive” form of table was in place from the Fund’s inception in 2002 through April 30, 2020 and is currently in place since May 1, 2021.

Generally, the Investment Manager will determine the current state of the equity market to be “normal” when its analysis of the S&P 500^® Index’s cyclically adjusted price-to-earnings ratio for the prior seven years is outside the top quartile of ratio observations over a 40-year history. The “normal” equity market form of allocation table for the Fund is also structured around the 50/50 Band, with allocations to bonds decreasing through stratified range bands below the 50/50 Band, and allocations to stocks and bonds set at 50% stocks/50% bonds for all trading levels above the 50/50 Band, as shown by the following example:

“Normal” Equity Market Form of Stock/Bond Allocation Table
Level of the S&P 500® Index	Stock Percentage	Bond Percentage
above trading range that is 2% below implied median (50/50 Band)*	50%	50%
4% trading range below bottom of range above	55%	45%
4% trading range below bottom of range above	60%	40%
4% trading range below bottom of range above	65%	35%
4% trading range below bottom of range above	70%	30%
4% trading range below bottom of range above	75%	25%
4% trading range below bottom of range above	80%	20%
4% trading range below bottom of range above	85%	15%
below bottom of trading range above	90%	10%

*Implied median price level as calculated by the Investment Manager.

The “normal” form of allocation table was in place from May 1, 2020 through April 30, 2021.

The Investment Manager will conduct the market state review at least annually prior to the annual updating of this prospectus, and may, in its discretion, assess the market state on an “emergency” basis and make any changes deemed necessary to reflect, for example, a very significant move in market levels or a structural change affecting the markets.

Any such “emergency” changes by the Investment Manager, which are expected to be infrequent, would be disclosed in this prospectus.

Risk [Heading]

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Principal Risks

Risk Narrative [Text Block]

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An investment in the Fund involves risks, including general risks, as described below, relating to the Fund’s investment process and its “fund-of-funds” structure. An investment in the Fund also involves specific risks related to the individual Portfolio Funds, including but not limited to those described below, which in the aggregate are considered principal risks of investing in the Fund. More information about the Portfolio Funds, including their principal risks, is available in their prospectuses. This prospectus is not an offer for any of the Portfolio Funds. There is no assurance that the Fund will achieve its investment objective and you may lose money. The value of the Fund’s holdings may decline, and the Fund’s net asset value (NAV) and share price may go down. An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

Allocation Risk. The Investment Manager uses an asset allocation strategy in pursuit of its investment objective, there is a risk that the Fund's allocation among asset classes or investments will cause the Fund's shares to lose value or cause the Fund to underperform other funds with similar investment objectives and/or strategies, or that the investments themselves will not produce the returns expected.

Fund-of-Funds Risk. Determinations regarding asset classes or Portfolio Funds and the Fund’s allocations thereto may not successfully achieve the Fund’s investment objective, in whole or in part. The selected Portfolio Funds’ performance may be lower than the performance of the asset class they were selected to represent or may be lower than the performance of alternative Portfolio Funds that could have been selected to represent the asset class. The Fund also is exposed to the same risks as the Portfolio Funds in direct proportion to the allocation of its assets among the Portfolio Funds. By investing in a combination of Portfolio Funds, the Fund has exposure to the risks of many areas of the market. The ability of the Fund to realize its investment objective will depend, in large part, on the extent to which the Portfolio Funds realize their investment objectives. There is no guarantee that the Portfolio Funds will achieve their respective investment objectives. The performance of Portfolio Funds could be adversely affected if other entities that invest in the same Portfolio Funds make relatively large investments or redemptions in such Portfolio Funds. The Fund, and its shareholders, indirectly bear a portion of the expenses of any funds in which the Fund invests. Because the expenses and costs of each Portfolio Fund are shared by its investors, redemptions by other investors in a Portfolio Fund could result in decreased economies of scale and increased operating expenses for such fund. These transactions might also result in higher brokerage, tax or other costs for a Portfolio Fund. This risk may be particularly important when one investor owns a substantial portion of a Portfolio Fund. The Investment Manager may have potential conflicts of interest in selecting affiliated funds over unaffiliated funds for investment by the Fund, and may also face potential conflicts of interest in selecting affiliated funds, because the fees the Investment Manager receives from some Portfolio Funds may be higher than the fees paid by other Portfolio Funds. Further, because of the Investment Manager’s confidence in its own strategies, investment philosophy and capacities, it will, in selecting Portfolio Funds, at times prefer a fund in the Columbia Acorn Family of Funds over alternative investments. There can be no assurance, however, that a fund in the Columbia Acorn Family of Funds selected for inclusion in Columbia Thermostat Fund’s portfolio will, in fact, outperform similar funds managed by the Investment Manager’s affiliates. Columbia Thermostat Fund currently invests only in affiliated Portfolio Funds. 

The Fund is subject indirectly to the risks of the Portfolio Funds described below. References to the “Fund” in the risk disclosures below refer to the Portfolio Funds and not Columbia Thermostat Fund. References to the “Investment Manager” in the risk disclosures below refer to the Fund's Investment Manager and/or Columbia Management as appropriate. Please see the Portfolio Funds Summary in the statutory prospectus for the Fund for information about the risks that apply to the Portfolio Funds. 

Market Risk. The Fund may incur losses due to declines in the value of one or more securities in which it invests. These declines may be due to factors affecting a particular issuer, or the result of, among other things, political, regulatory, market, economic or social developments affecting the relevant market(s) more generally. In addition, turbulence in financial markets and reduced liquidity in equity, credit and/or fixed income markets may negatively affect many issuers, which could adversely affect the Fund’s ability to price or value hard-to-value assets in thinly traded and closed markets and could cause significant redemptions and operational challenges. Global economies and financial markets are increasingly interconnected, and conditions and events in one country, region or financial 

market may adversely impact issuers in a different country, region or financial market. These risks may be magnified if certain events or developments adversely interrupt the global supply chain; in these and other circumstances, such risks might affect companies worldwide. As a result, local, regional or global events such as terrorism, war, other conflicts, natural disasters, disease/virus outbreaks and epidemics or other public health issues, recessions, depressions or other events – or the potential for such events – could have a significant negative impact on global economic and market conditions. 

The large-scale invasion of Ukraine by Russia in February 2022 has resulted in sanctions and market disruptions including declines in regional and global stock and commodity markets and significant devaluations of Russian currency. The extent and duration of the military action are impossible to predict but could be significant. Market disruption caused by the Russian military action, and any counter measures or responses thereto (including international sanctions, a downgrade in the country’s credit rating, purchasing and financing restrictions, boycotts, tariffs, changes in consumer or purchaser preferences, cyberattacks and espionage) could have severe adverse impacts on regional and/or global securities and commodities markets, including markets for oil and natural gas. These impacts may include reduced market liquidity, distress in credit markets, further disruption of global supply chains, increased risk of inflation, and limited access to investments in certain international markets and/or issuers. These developments and other related events could negatively impact Fund performance. 

The pandemic caused by coronavirus disease 2019 and its variants (COVID-19) has resulted in, and may continue to result in, significant global economic and societal disruption and market volatility due to disruptions in market access, resource availability, facilities operations, imposition of tariffs, export controls and supply chain disruption, among others. Such disruptions may be caused, or exacerbated by, quarantines and travel restrictions, workforce displacement and loss in human and other resources. The uncertainty surrounding the magnitude, duration, reach, costs and effects of the global pandemic, as well as actions that have been or could be taken by governmental authorities or other third parties, present unknowns that are yet to unfold. The impacts, as well as the uncertainty over impacts to come, of COVID-19 – and any other infectious illness outbreaks, epidemics and pandemics that may arise in the future – could negatively affect global economies and markets in ways that cannot necessarily be foreseen. In addition, the impact of infectious illness outbreaks and epidemics in less developed countries may be greater due to generally less established healthcare systems, governments and financial markets. Public health crises caused by the COVID-19 outbreak may exacerbate other pre-existing political, social and economic risks in certain countries or globally. The disruptions caused by COVID-19 could prevent the Fund from executing advantageous investment decisions in a timely manner and negatively impact the Fund’s ability to achieve its investment objective. Any such events could have a significant adverse impact on the value and risk profile of the Fund. 

Active Management Risk. Due to its active management, the Fund could underperform its benchmark index and/or other funds with similar investment objectives and/or strategies. 

Interest Rate Risk. Interest rate risk is the risk of losses attributable to changes in interest rates. In general, if prevailing interest rates rise, the values of loans and other debt instruments tend to fall, and if interest rates fall, the values of loans and other debt instruments tend to rise. Changes in the value of a debt instrument usually will not affect the amount of income the Fund receives from it but will generally affect the value of your investment in the Fund. Changes in interest rates may also affect the liquidity of the Fund’s investments in debt instruments. In general, the longer the maturity or duration of a debt instrument, the greater its sensitivity to changes in interest rates. Interest rate declines also may increase prepayments of debt obligations, which, in turn, would increase prepayment risk (the risk that the Fund will have to reinvest the money received in securities that have lower yields). Very low or negative interest rates may impact the Fund’s yield and may increase the risk that, if followed by rising interest rates, the Fund’s performance will be negatively impacted. The Fund is subject to the risk that the income generated by its investments may not keep pace with inflation. Actions by governments and central banking authorities can result in increases or decreases in interest rates. Higher periods of inflation could lead such authorities to raise interest rates. Such actions may negatively affect the value of debt instruments held by the Fund, resulting in a negative impact on the Fund's performance and NAV. Securities with floating interest rates are typically less sensitive to interest rate changes, but may decline in value if their interest rates do not rise as much as interest rates in general. Because rates on certain floating rate loans and other debt securities reset only periodically, 

changes in prevailing interest rates (and particularly sudden and significant changes) can be expected to cause fluctuations in the Fund’s NAV. Any interest rate increases could cause the value of the Fund’s investments in debt instruments to decrease. Rising interest rates may prompt redemptions from the Fund, which may force the Fund to sell investments at a time when it is not advantageous to do so, which could result in losses. 

Credit Risk. Credit risk is the risk that the value of loans or other debt instruments may decline if the issuer thereof defaults or otherwise becomes unable or unwilling, or is perceived to be unable or unwilling, to honor its financial obligations, such as making payments to the Fund when due. Various factors could affect the actual or perceived willingness or ability of the issuer to make timely interest or principal payments, including changes in the financial condition of the issuer or in general economic conditions. Credit rating agencies, such as S&P Global Ratings, Moody’s Investors Service, Inc. (Moody’s), Fitch Ratings, Inc. (Fitch), DBRS Morningstar (DBRS) and Kroll Bond Rating Agency, LLC (KBRA), assign credit ratings to certain debt instruments to indicate their credit risk. A rating downgrade by such agencies can negatively impact the value of such instruments. Lower-rated or unrated instruments held by the Fund may present increased credit risk as compared to higher-rated instruments. Non-investment grade debt instruments may be subject to greater price fluctuations and are more likely to experience a default than investment grade debt instruments and therefore may expose the Fund to increased credit risk. If the Fund purchases unrated instruments, or if the ratings of instruments held by the Fund are lowered after purchase, the Fund will depend on analysis of credit risk more heavily than usual. 

Preferred Stock Risk. Preferred stock is a type of stock that may pay dividends at a different rate than common stock of the same issuer, if at all, and that has preference over common stock in the payment of dividends and the liquidation of assets. Preferred stock does not ordinarily carry voting rights. The price of a preferred stock is generally determined by earnings, type of products or services, projected growth rates, experience of management, liquidity, and general market conditions of the markets on which the stock trades. The most significant risks associated with investments in preferred stock include issuer risk, market risk and interest rate risk (the risk of losses attributable to changes in interest rates). 

High-Yield Investments Risk. Securities and other debt instruments held by the Fund that are rated below investment grade (commonly called “high-yield” or “junk” bonds) and unrated debt instruments of comparable quality tend to be more sensitive to credit risk than higher-rated debt instruments and may experience greater price fluctuations in response to perceived changes in the ability of the issuing entity or obligor to pay interest and principal when due than to changes in interest rates. These investments are generally more likely to experience a default than higher-rated debt instruments. High-yield debt instruments are considered to be predominantly speculative with respect to the issuer’s capacity to pay interest and repay principal. These debt instruments typically pay a premium – a higher interest rate or yield – because of the increased risk of loss, including default. High-yield debt instruments may require a greater degree of judgment to establish a price, may be difficult to sell at the time and price the Fund desires, may carry high transaction costs, and also are generally less liquid than higher-rated debt instruments. The ratings provided by third party rating agencies are based on analyses by these ratings agencies of the credit quality of the debt instruments and may not take into account every risk related to whether interest or principal will be timely repaid. In adverse economic and other circumstances, issuers of lower-rated debt instruments are more likely to have difficulty making principal and interest payments than issuers of higher-rated debt instruments. 

Value Securities Risk. Value securities are securities of companies that may have experienced, for example, adverse business, industry or other developments or may be subject to special risks that have caused the securities to be out of favor and, in turn, potentially undervalued. The market value of a portfolio security may not meet the Portfolio Fund’s Investment Manager’s perceived value assessment of that security, or may decline in price, even though the Portfolio Fund’s Investment Manager believes the securities are already undervalued. There is also a risk that it may take longer than expected for the value of these investments to rise to the portfolio manager’s perceived value. In addition, value securities, at times, may not perform as well as growth securities or the stock market in general, and may be out of favor with investors for varying periods of time. 

Growth Securities Risk. Growth securities typically trade at a higher multiple of earnings than other types of equity securities. Accordingly, the market values of growth securities may never reach their expected market value and may decline in price. In addition, growth securities, at times, may not perform as well as value securities or the stock market in general, and may be out of favor with investors for varying periods of time. 

Sector Risk. At times, the Fund may have a significant portion of its assets invested in securities of companies conducting business within one or more economic sectors. Companies in the same sector may be similarly affected by economic, regulatory, political or market events or conditions, which may make the Fund more vulnerable to unfavorable developments in that sector than funds that invest more broadly. Generally, the more broadly the Fund invests, the more it spreads risk and potentially reduces the risks of loss and volatility. 

■ Consumer Discretionary Sector. The Fund is more susceptible to the particular risks that may affect companies in the consumer discretionary sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the consumer discretionary sector are subject to certain risks, including fluctuations in the performance of the overall domestic and international economy, interest rate changes, increased competition and consumer confidence. Performance of such companies may be affected by factors including reduced disposable household income, reduced consumer spending, and changing demographics and consumer tastes. 

■ Financial Services Sector. The Fund is more susceptible to the particular risks that may affect companies in the financial services sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the financial services sector are subject to certain risks, including the risk of regulatory change, decreased liquidity in credit markets and unstable interest rates. Such companies may have concentrated portfolios, such as a high level of loans to one or more industries or sectors, which makes them vulnerable to economic conditions that affect such industries or sectors. Performance of such companies may be affected by competitive pressures and exposure to investments, agreements and counterparties, including credit products that, under certain circumstances, may lead to losses (e.g., subprime loans). Companies in the financial services sector are subject to extensive governmental regulation that may limit the amount and types of loans and other financial commitments they can make, and the interest rates and fees they may charge. In addition, profitability of such companies is largely dependent upon the availability and the cost of capital. 

■ Information Technology Sector. The Fund is more susceptible to the particular risks that may affect companies in the information technology sector than if it were invested in a wider variety of companies in unrelated sectors. Companies in the information technology sector are subject to certain risks, including the risk that new services, equipment or technologies will not be accepted by consumers and businesses or will become rapidly obsolete. Performance of such companies may be affected by factors including obtaining and protecting patents (or the failure to do so) and significant competitive pressures, including aggressive pricing of their products or services, new market entrants, competition for market share and short product cycles due to an accelerated rate of technological developments. Such competitive pressures may lead to limited earnings and/or falling profit margins. As a result, the value of their securities may fall or fail to rise. In addition, many information technology sector companies have limited operating histories and prices of these companies’ securities historically have been more volatile than other securities, especially over the short term. Some companies in the information technology sector are facing increased government and regulatory scrutiny and may be subject to adverse government or regulatory action, which could negatively impact the value of their securities. 

Foreign Securities Risk. Investments in or exposure to securities of foreign companies may involve heightened risks relative to investments in or exposure to securities of U.S. companies. For example, foreign markets can be extremely volatile. Foreign securities may also be less liquid, making them more difficult to trade, than securities of U.S. companies so that the Fund may, at times, be unable to sell foreign securities at desirable times or prices. Brokerage commissions, custodial costs and other fees are also generally higher for foreign securities. The Fund may have limited or no legal recourse in the event of default with respect to certain foreign securities, including those issued by foreign governments. In addition, foreign governments may impose withholding or other taxes on the Fund’s income, capital gains or proceeds from the disposition of foreign securities, which could reduce the Fund’s return on such securities. In some cases, such withholding or other taxes could potentially be confiscatory. Other risks include: possible delays in the settlement of transactions or in the payment of income; generally less publicly available information about foreign companies; the impact of economic, political, social, diplomatic or other conditions or events (including, for example, military confrontations and actions, war, other conflicts, terrorism and disease/virus outbreaks and epidemics), possible seizure, expropriation or nationalization of a company or its assets or the assets of a particular investor or category of investors; accounting, auditing and financial reporting standards that may be less comprehensive and stringent than those applicable to domestic companies; the imposition of economic and 

other sanctions against a particular foreign country, its nationals or industries or businesses within the country; and the generally less stringent standard of care to which local agents may be held in the local markets. In addition, it may be difficult to obtain reliable information about the securities and business operations of certain foreign issuers. Governments or trade groups may compel local agents to hold securities in designated depositories that are not subject to independent evaluation. The less developed a country’s securities market is, the greater the level of risks. Economic sanctions may be, and have been, imposed against certain countries, organizations, companies, entities and/or individuals. Economic sanctions and other similar governmental actions could, among other things, effectively restrict or eliminate the Fund’s ability to purchase or sell securities, and thus may make the Fund’s investments in such securities less liquid or more difficult to value. In addition, as a result of economic sanctions, the Fund may be forced to sell or otherwise dispose of investments at inopportune times or prices, which could result in losses to the Fund and increased transaction costs. These conditions may be in place for a substantial period of time and enacted with limited advance notice to the Fund. The risks posed by sanctions against a particular foreign country, its nationals or industries or businesses within the country may be heightened to the extent the Fund invests significantly in the affected country or region or in issuers from the affected country that depend on global markets. Additionally, investments in certain countries may subject the Fund to a number of tax rules, the application of which may be uncertain. Countries may amend or revise their existing tax laws, regulations and/or procedures in the future, possibly with retroactive effect. Changes in or uncertainties regarding the laws, regulations or procedures of a country could reduce the after-tax profits of the Fund, directly or indirectly, including by reducing the after-tax profits of companies located in such countries in which the Fund invests, or result in unexpected tax liabilities for the Fund. 

Operational and Settlement Risks of Foreign Securities. The Fund’s foreign securities are generally held outside the United States in the primary market for the securities in the custody of certain eligible foreign banks and trust companies (“foreign sub-custodians”), as permitted under the Investment Company Act of 1940 (the 1940 Act). Settlement practices for foreign securities may differ from those in the United States. Some countries have limited governmental oversight and regulation of industry practices, stock exchanges, depositories, registrars, brokers and listed companies, which increases the risk of corruption and fraud and the possibility of losses to the Fund. In particular, under certain circumstances, foreign securities may settle on a delayed delivery basis, meaning that the Fund may be required to make payment for securities before the Fund has actually received delivery of the securities or deliver securities prior to the receipt of payment. Typically, in these cases, the Fund will receive evidence of ownership in accordance with the generally accepted settlement practices in the local market entitling the Fund to delivery or payment at a future date, but there is a risk that the security will not be delivered to the Fund or that payment will not be received, although the Fund and its foreign sub-custodians take reasonable precautions to mitigate this risk. Losses can also result from lost, stolen or counterfeit securities; defaults by brokers and banks; failures or defects of the settlement system; or poor and improper record keeping by registrars and issuers. 

Share Blocking. Share blocking refers to a practice in certain foreign markets under which an issuer’s securities are blocked from trading at the custodian or sub-custodian level for a specified number of days before and, in certain instances, after a shareholder meeting where a vote of shareholders takes place. The blocking period can last up to several weeks. Share blocking may prevent the Fund from buying or selling securities during this period, because during the time shares are blocked, trades in such securities will not settle. It may be difficult or impossible to lift blocking restrictions, with the particular requirements varying widely by country. As a consequence of these restrictions, the Portfolio Fund's Investment Manager, on behalf of the Fund, may abstain from voting proxies in markets that require share blocking. 

Emerging Market Securities Risk. Securities issued by foreign governments or companies in emerging market countries, such as China, Russia and certain countries in Eastern Europe, the Middle East, Asia, Latin America or Africa, are more likely to have greater exposure to the risks of investing in foreign securities that are described in Foreign Securities Risk. In addition, emerging market countries are more likely to experience instability resulting, for example, from rapid changes or developments in social, political, economic or other conditions. Their economies are usually less mature and their securities markets are typically less developed with more limited trading activity (i.e., lower trading volumes and less liquidity) than more developed countries. Emerging market securities tend to be more volatile, and may be more susceptible to market manipulation, than securities in more developed markets. Many emerging market countries are heavily dependent on international trade and have fewer trading partners, which 

makes them more sensitive to world commodity prices and economic downturns in other countries. Some emerging market countries have a higher risk of currency devaluations, and some of these countries may experience periods of high inflation or rapid changes in inflation rates and may have hostile relations with other countries. Due to the differences in the nature and quality of financial information of issuers of emerging market securities, including auditing and financial reporting standards, financial information and disclosures about such issuers may be unavailable or, if made available, may be considerably less reliable than publicly available information about other foreign securities. 

Operational and Settlement Risks of Securities in Emerging Markets. In addition to having less developed securities markets, banks in emerging markets that are eligible foreign sub-custodians may be recently organized, lack extensive operating experience or lack effective government oversight or regulation. In addition, there may be legal restrictions or limitations on the ability of the Fund to recover assets held in custody by a foreign sub-custodian in the event of the bankruptcy of the sub-custodian. Because settlement systems may be less organized than in developed markets and because delivery versus payment settlement may not be possible or reliable, there may be a greater risk that settlement may be delayed and that cash or securities of the Fund may be lost because of failures of or defects in the system, including fraud or corruption. Settlement systems in emerging markets also have a higher risk of failed trades. 

Risks Related to Currencies and Corporate Actions in Emerging Markets. Risks related to currencies and corporate actions are also greater in emerging market countries than in developed countries. For example, some emerging market countries may have fixed or managed currencies that are not free-floating against the U.S. dollar. Further, certain currencies may not have an active trading market internationally, or countries may have varying exchange rates. Some emerging market countries have a higher risk of currency devaluations, and some of these countries may experience sustained periods of high inflation or rapid changes in inflation rates which can have negative effects on a country’s economy and securities markets. Corporate action procedures in emerging market countries may be less reliable and have limited or no involvement by the depositories and central banks. Lack of standard practices and payment systems can lead to significant delays in payment. 

Risks Related to Corporate and Securities Laws in Emerging Markets. Securities laws in emerging markets may be relatively new and unsettled and, consequently, there is a risk of rapid and unpredictable change in laws regarding foreign investment, securities regulation, title to securities and shareholder rights. Accordingly, foreign investors may be adversely affected by new or amended laws and regulations. In addition, the systems of corporate governance to which issuers in certain emerging markets are subject may be less advanced than the systems to which issuers located in more developed countries are subject, and therefore, shareholders of such issuers may not receive many of the protections available to shareholders of issuers located in more developed countries. These risks may be heightened in China and Russia. 

Sovereign Debt Risk. The willingness or ability of a sovereign or quasi-sovereign debtor to repay principal and pay interest in a timely manner may be affected by a variety of factors, including its cash flow situation, the extent of its reserves, the availability of sufficient foreign exchange on the date a payment is due, the relative size of the debt service burden to the economy as a whole, the sovereign or quasi-sovereign debtor’s policy toward international lenders, and the political constraints to which such debtor may be subject. 

With respect to sovereign or quasi-sovereign debt of emerging market issuers, investors should be aware that certain emerging market countries are among the largest debtors to commercial banks and foreign governments. At times, certain emerging market countries have declared moratoria on the payment of principal and interest on external debt. Certain emerging market countries have experienced difficulty in servicing their sovereign or quasi-sovereign debt on a timely basis and that has led to defaults and the restructuring of certain indebtedness to the detriment of debt-holders. 

Foreign Currency Risk. The performance of the Fund may be materially affected positively or negatively by foreign currency strength or weakness relative to the U.S. dollar, particularly if the Fund invests a significant percentage of its assets in foreign securities or other assets denominated in currencies other than the U.S. dollar. Currency rates in foreign countries may fluctuate significantly over short or long periods of time for a number of reasons, including changes in interest rates, imposition of currency controls and economic or political developments in the U.S. or 

abroad. The Fund may also incur currency conversion costs when converting foreign currencies into U.S. dollars and vice versa. Restrictions on currency trading may be imposed by foreign countries, which may adversely affect the value of your investment in the Fund. Even though the currencies of some countries may be pegged to the U.S. dollar, the conversion rate may be controlled by government regulation or intervention at levels significantly different than what would normally prevail in a free market. Significant revaluations of the U.S. dollar exchange rate of these currencies could cause substantial reductions in the Fund’s NAV. 

Liquidity and Trading Volume Risk. Due to market conditions, including uncertainty regarding the price of a security, it may be difficult for the Fund to buy or sell portfolio securities at a desirable time or price, which could result in investment losses. This risk of portfolio illiquidity is heightened with respect to small- and mid-cap securities, generally, and foreign small- and mid-cap securities in particular. The Fund may have to lower the selling price, liquidate other investments, or forego another, more appealing investment opportunity as a result of illiquidity in the markets. The Investment Manager will fair value in good faith any securities it deems to be illiquid under consistently applied procedures established by the Fund’s Board. Market conditions are always changing and vary by country and industry sector, and investing in international markets involves unique risks. Although it is difficult to accurately assess trends in trading volumes in foreign markets, a reduction in trading volumes poses challenges to the Fund. This is particularly so because the Fund focuses on small- and mid-cap companies that usually have lower trading volumes and often takes sizeable positions in portfolio companies. As a result of lower trading volumes, it may take longer to buy or sell securities, which can exacerbate the Fund’s exposure to volatile markets. The Fund may also be limited in its ability to execute favorable trades in portfolio securities in response to changes in share prices and fundamentals. If the Fund is forced to sell securities to meet redemption requests or other cash needs, or in the case of an event affecting liquidity in a particular market or markets, it may be forced to dispose of those securities under disadvantageous circumstances and at a loss. As the Fund grows in size or, conversely, if it faces significant redemption pressure, these considerations take on increasing significance and may adversely impact performance. 

Focused Portfolio Risk. Because the Fund may invest in a limited number of companies, the Fund as a whole is subject to greater risk of loss if any of those securities decline in price. 

Issuer Risk. An issuer in which the Fund invests or to which it has exposure may perform poorly or below expectations, and the value of its securities may therefore decline, which may negatively affect the Fund’s performance. Underperformance of an issuer may be caused by poor management decisions, competitive pressures, breakthroughs in technology, reliance on suppliers, labor problems or shortages, corporate restructurings, fraudulent disclosures, natural disasters, military confrontations and actions, war, terrorism, disease/virus outbreaks, epidemics or other events, conditions and factors which may impair the value of an investment in the Fund. 

■ Small- and Mid-Cap Stock Risk. Investments in small- and mid-capitalization companies (small- and mid-cap companies) often involve greater risks than investments in larger, more established companies (larger companies) because small- and mid-cap companies tend to have less predictable earnings and may lack the management experience, financial resources, product diversification and competitive strengths of larger companies. Securities of small- and mid-cap companies may be less liquid and more volatile than the securities of larger companies. 

■ Large-Cap Stock Risk. Investments in larger, more established companies (larger companies) may involve certain risks associated with their larger size. For instance, larger companies may be less able to respond quickly to new competitive challenges, such as changes in consumer tastes or innovation from smaller competitors. Also, larger companies are sometimes less able to achieve as high growth rates as successful smaller companies, especially during extended periods of economic expansion. 

U.S. Government Obligations Risk. While U.S. Treasury obligations are backed by the “full faith and credit” of the U.S. Government, such securities are nonetheless subject to credit risk (i.e., the risk that the U.S. Government may be, or may be perceived to be, unable or unwilling to honor its financial obligations, such as making payments). Securities issued or guaranteed by federal agencies or authorities and U.S. Government-sponsored instrumentalities or enterprises may or may not be backed by the full faith and credit of the U.S. Government. For example, securities issued by the Federal Home Loan Mortgage Corporation, the Federal National Mortgage Association and the Federal 

Home Loan Banks are neither insured nor guaranteed by the U.S. Government. These securities may be supported by the ability to borrow from the U.S. Treasury or only by the credit of the issuing agency, authority, instrumentality or enterprise and, as a result, are subject to greater credit risk than securities issued or guaranteed by the U.S. Treasury. 

Derivatives Risk. Derivatives may involve significant risks. Derivatives are financial instruments, traded on an exchange or in the over-the-counter (OTC) markets, with a value in relation to, or derived from, the value of an underlying asset(s) (such as a security, commodity or currency) or other reference, such as an index, rate or other economic indicator (each an underlying reference). Derivatives may include those that are privately placed or otherwise exempt from SEC registration, including certain Rule 144A eligible securities. Derivatives could result in Fund losses if the underlying reference does not perform as anticipated. Use of derivatives is a highly specialized activity that can involve investment techniques, risks, and tax planning different from those associated with more traditional investment instruments. The Fund’s derivatives strategy may not be successful and use of certain derivatives could result in substantial, potentially unlimited, losses to the Fund regardless of the Fund’s actual investment. A relatively small movement in the price, rate or other economic indicator associated with the underlying reference may result in substantial losses for the Fund. Derivatives may be more volatile than other types of investments. Derivatives can increase the Fund’s risk exposure to underlying references and their attendant risks, including the risk of an adverse credit event associated with the underlying reference (credit risk), the risk of an adverse movement in the value, price or rate of the underlying reference (market risk), the risk of an adverse movement in the value of underlying currencies (foreign currency risk) and the risk of an adverse movement in underlying interest rates (interest rate risk). Derivatives may expose the Fund to additional risks, including the risk of loss due to a derivative position that is imperfectly correlated with the underlying reference it is intended to hedge or replicate (correlation risk), the risk that a counterparty will fail to perform as agreed (counterparty risk), the risk that a hedging strategy may fail to mitigate losses, and may offset gains (hedging risk), the risk that the return on an investment may not keep pace with inflation (inflation risk), the risk that losses may be greater than the amount invested (leverage risk), the risk that the Fund may be unable to sell an investment at an advantageous time or price (liquidity risk), the risk that the investment may be difficult to value (pricing risk), and the risk that the price or value of the investment fluctuates significantly over short periods of time (volatility risk). The value of derivatives may be influenced by a variety of factors, including national and international political and economic developments. Potential changes to the regulation of the derivatives markets may make derivatives more costly, may limit the market for derivatives, or may otherwise adversely affect the value or performance of derivatives. 

Derivatives Risk – Forward Contracts Risk. A forward contract is an over-the-counter derivative transaction between two parties to buy or sell a specified amount of an underlying reference at a specified price (or rate) on a specified date in the future. Forward contracts are negotiated on an individual basis and are not standardized or traded on exchanges. The market for forward contracts is substantially unregulated (there is no limit on daily price movements and speculative position limits are not applicable). The principals who deal in certain forward contract markets are not required to continue to make markets in the underlying references in which they trade and these markets can experience periods of illiquidity, sometimes of significant duration. There have been periods during which certain participants in forward contract markets have refused to quote prices for certain underlying references or have quoted prices with an unusually wide spread between the price at which they were prepared to buy and that at which they were prepared to sell. At or prior to maturity of a forward contract, the Fund may enter into an offsetting contract and may incur a loss to the extent there has been adverse movement in forward contract prices. The liquidity of the markets for forward contracts depends on participants entering into offsetting transactions rather than making or taking delivery. To the extent participants make or take delivery, liquidity in the market for forwards could be reduced. A relatively small price movement in a forward contract may result in substantial losses to the Fund, exceeding the amount of the margin paid. Forward contracts can increase the Fund’s risk exposure to underlying references and their attendant risks, such as credit risk, market risk, foreign currency risk and interest rate risk, while also exposing the Fund to correlation risk, counterparty risk, hedging risk, inflation risk, leverage risk, liquidity risk, pricing risk and volatility risk. 

■ A forward foreign currency contract is a derivative (forward contract) in which the underlying reference is a country's or region’s currency. The Fund may agree to buy or sell a country's or region’s currency at a specific 

price on a specific date in the future. These instruments may fall in value (sometimes dramatically) due to foreign market downswings or foreign currency value fluctuations, subjecting the Fund to foreign currency risk (the risk that Fund performance may be negatively impacted by foreign currency strength or weakness relative to the U.S. dollar, particularly if the Fund exposes a significant percentage of its assets to currencies other than the U.S. dollar). Unanticipated changes in the currency markets could result in reduced performance for the Fund. When the Fund converts its foreign currencies into U.S. dollars, it may incur currency conversion costs due to the spread between the prices at which it may buy and sell various currencies in the market. 

Derivatives Risk – Futures Contracts Risk. A futures contract is an exchange-traded derivative transaction between two parties in which a buyer (holding the “long” position) agrees to pay a fixed price (or rate) at a specified future date for delivery of an underlying reference from a seller (holding the “short” position). The seller hopes that the market price on the delivery date is less than the agreed upon price, while the buyer hopes for the contrary. Certain futures contract markets are highly volatile, and futures contracts may be illiquid. Futures exchanges may limit fluctuations in futures contract prices by imposing a maximum permissible daily price movement. The Fund may be disadvantaged if it is prohibited from executing a trade outside the daily permissible price movement. At or prior to maturity of a futures contract, the Fund may enter into an offsetting contract and may incur a loss to the extent there has been adverse movement in futures contract prices. The liquidity of the futures markets depends on participants entering into offsetting transactions rather than making or taking delivery. To the extent participants make or take delivery, liquidity in the futures market could be reduced. Positions in futures contracts may be closed out only on the exchange on which they were entered into or through a linked exchange, and no secondary market exists for such contracts. Futures positions are marked to market each day and variation margin payment must be paid to or by the Fund. Because of the low margin deposits normally required in futures trading, it is possible that the Fund may employ a high degree of leverage in the portfolio. As a result, a relatively small price movement in a futures contract may result in substantial losses to the Fund, exceeding the amount of the margin paid. For certain types of futures contracts, losses are potentially unlimited. Futures markets are highly volatile and the use of futures may increase the volatility of the Fund’s NAV. Futures contracts executed (if any) on foreign exchanges may not provide the same protection as U.S. exchanges. Futures contracts can increase the Fund’s risk exposure to underlying references and their attendant risks, such as credit risk, market risk, foreign currency risk, and interest rate risk, while also exposing the Fund to correlation risk, counterparty risk, hedging risk, inflation risk, leverage risk, liquidity risk, pricing risk and volatility risk. 

■ An interest rate future is a derivative that is an agreement whereby the buyer and seller agree to the future delivery of an interest-bearing instrument on a specific date at a pre-determined price. Examples include Treasury-bill futures, Treasury-bond futures and Eurodollar futures. 

Derivatives Risk – Options Risk. Options are derivatives that give the purchaser the option to buy (call) or sell (put) an underlying reference from or to a counterparty at a specified price (the strike price) on or before an expiration date. When writing options, the Fund is exposed to the risk that it may be required to buy or sell the underlying reference at a disadvantageous price on or before the expiration date. Options may involve economic leverage, which could result in greater volatility in price movement. The Fund's losses could be significant, and are potentially unlimited for certain types of options. Options may be traded on a securities exchange or in the over-the-counter market. At or prior to maturity of an options contract, the Fund may enter into an offsetting contract and may incur a loss to the extent there has been adverse movement in options prices. Options can increase the Fund’s risk exposure to underlying references and their attendant risks such as credit risk, market risk, foreign currency risk and interest rate risk, while also exposing the Fund to correlation risk, counterparty risk, hedging risk, inflation risk, leverage risk, liquidity risk, pricing risk and volatility risk. 

Derivatives Risk – Swaps Risk. In a typical swap transaction, two parties agree to exchange the return earned on a specified underlying reference for a fixed return or the return from another underlying reference during a specified period of time. Swaps may be difficult to value and may be illiquid. Swaps could result in Fund losses if the underlying asset or reference does not perform as anticipated. Swaps create significant investment leverage such that a relatively small price movement in a swap may result in immediate and substantial losses to the Fund. The Fund may only close out a swap with its particular counterparty, and may only transfer a position with the consent of that counterparty. Certain swaps, such as short swap transactions and total return swaps, have the potential for 

unlimited losses, regardless of the size of the initial investment. Swaps can increase the Fund’s risk exposure to underlying references and their attendant risks, such as credit risk, market risk, foreign currency risk and interest rate risk, while also exposing the Fund to correlation risk, counterparty risk, hedging risk, inflation risk, leverage risk, liquidity risk, pricing risk and volatility risk. 

■ A credit default swap (including a swap on a credit default index, sometimes referred to as a credit default swap index) is a derivative and special type of swap where one party pays, in effect, an insurance premium through a stream of payments to another party in exchange for the right to receive a specified return upon the occurrence of a particular credit event by one or more third parties, such as bankruptcy, default or a similar event. A credit default swap may be embedded within a structured note or other derivative instrument. Credit default swaps enable an investor to buy or sell protection against such a credit event (such as an issuer’s bankruptcy, restructuring or failure to make timely payments of interest or principal). Credit default swap indices are indices that reflect the performance of a basket of credit default swaps and are subject to the same risks as credit default swaps. If such a default were to occur, any contractual remedies that the Fund may have may be subject to bankruptcy and insolvency laws, which could delay or limit the Fund's recovery. Thus, if the counterparty under a credit default swap defaults on its obligation to make payments thereunder, as a result of its bankruptcy or otherwise, the Fund may lose such payments altogether, or collect only a portion thereof, which collection could involve costs or delays. The Fund’s return from investment in a credit default swap index may not match the return of the referenced index. Further, investment in a credit default swap index could result in losses if the referenced index does not perform as expected. Unexpected changes in the composition of the index may also affect performance of the credit default swap index. If a referenced index has a dramatic intraday move that causes a material decline in the Fund’s net assets, the terms of the Fund’s credit default swap index may permit the counterparty to immediately close out the transaction. In that event, the Fund may be unable to enter into another credit default swap index or otherwise achieve desired exposure, even if the referenced index reverses all or a portion of its intraday move. 

Derivatives Risk – Swaptions Risk. A swaption is an options contract on a swap agreement. These transactions give the purchasing party the right (but not the obligation) to enter into new swap agreements or to shorten, extend, cancel or otherwise modify an existing swap agreement at some designated future time on specified terms, in return for payment of the purchase price (the “premium”) of the option. The Fund may write (sell) and purchase put and call swaptions to the same extent it may make use of standard options on securities or other instruments. The writer of the contract receives the premium and bears the risk of unfavorable changes in the market value on the underlying swap agreement. Swaptions can be bundled and sold as a package. These are commonly called interest rate caps, floors and collars. 

Convertible Securities Risk. Convertible securities are subject to the usual risks associated with debt instruments, such as interest rate risk (the risk of losses attributable to changes in interest rates) and credit risk (the risk that the issuer of a debt instrument will default or otherwise become unable, or be perceived to be unable or unwilling, to honor a financial obligation, such as making payments to the Fund when due). Convertible securities also react to changes in the value of the common stock into which they convert, and are thus subject to market risk (the risk that the market values of securities or other investments that the Fund holds will fall, sometimes rapidly or unpredictably, or fail to rise). Because the value of a convertible security can be influenced by both interest rates and the common stock's market movements, a convertible security generally is not as sensitive to interest rates as a similar debt instrument, and generally will not vary in value in response to other factors to the same extent as the underlying common stock. In the event of a liquidation of the issuing company, holders of convertible securities would typically be paid before the company's common stockholders but after holders of any senior debt obligations of the company. The Fund may be forced to convert a convertible security before it otherwise would choose to do so, which may decrease the Fund's return. 

Forward Commitments on Mortgage-Backed Securities (including Dollar Rolls) Risk. When purchasing mortgage-backed securities in the “to be announced” (TBA) market (MBS TBAs), the seller agrees to deliver mortgage-backed securities for an agreed upon price on an agreed upon date, but may make no guarantee as to the specific securities to be delivered. In lieu of taking delivery of mortgage-backed securities, the Fund could enter into dollar rolls, which are transactions in which the Fund sells securities to a counterparty and simultaneously agrees to purchase those or 

similar securities in the future at a predetermined price. Dollar rolls involve the risk that the market value of the securities the Fund is obligated to repurchase may decline below the repurchase price, or that the counterparty may default on its obligations. These transactions may also increase the Fund’s portfolio turnover rate. If the Fund reinvests the proceeds of the security sold, the Fund will also be subject to the risk that the investments purchased with such proceeds will decline in value (a form of leverage risk). MBS TBAs and dollar rolls are subject to the risk that the counterparty to the transaction may not perform or be unable to perform in accordance with the terms of the instrument. 

Stripped Securities Risk. Stripped securities are the separate income or principal components of debt securities. These securities are particularly sensitive to changes in interest rates, and therefore subject to greater fluctuations in price than typical interest bearing debt securities. For example, stripped mortgage-backed securities have greater interest rate risk than mortgage-backed securities with like maturities, and stripped treasury securities have greater interest rate risk (the risk of losses attributable to changes in interest rates) than traditional government securities with identical credit ratings. 

Prepayment and Extension Risk. Prepayment and extension risk is the risk that a bond or other security or investment might, in the case of prepayment risk, be called or otherwise converted, prepaid or redeemed before maturity and, in the case of extension risk, that the investment might not be called as expected. In the case of prepayment risk, if the investment is converted, prepaid or redeemed before maturity, the portfolio managers may not be able to invest the proceeds in other investments providing as high a level of income, resulting in a reduced yield to the Fund. In the case of mortgage- or other asset-backed securities, as interest rates decrease or spreads narrow, the likelihood of prepayment increases. Conversely, extension risk is the risk that an unexpected rise in interest rates will extend the life of a mortgage- or other asset-backed security beyond the prepayment time. If the Fund's investments are locked in at a lower interest rate for a longer period of time, the portfolio managers may be unable to capitalize on securities with higher interest rates or wider spreads. 

Reinvestment Risk. Reinvestment risk arises when the Fund is unable to reinvest income or principal at the same or at least the same return it is currently earning. 

Depositary Receipts Risk. Depositary receipts are receipts issued by a bank or trust company reflecting ownership of underlying securities issued by foreign companies. Some foreign securities are traded in the form of American Depositary Receipts and/or Global Depositary Receipts. Depositary receipts involve risks similar to the risks associated with investments in foreign securities, including those associated with an issuer’s (and any of its related companies’) country of organization and places of business operations, which may be related to the particular political, regulatory, economic, social and other conditions or events (including, for example, military confrontations and actions, war, terrorism and disease/virus outbreaks and epidemics) occurring in the country and fluctuations in such country’s currency, as well as market risk tied to the underlying foreign company. In addition, holders of depositary receipts may have limited voting rights, may not have the same rights afforded to stockholders of a typical domestic company in the event of a corporate action, such as an acquisition, merger or rights offering, and may experience difficulty in receiving company stockholder communications. There is no guarantee that a financial institution will continue to sponsor a depositary receipt, or that a depositary receipt will continue to trade on an exchange, either of which could adversely affect the liquidity, availability and pricing of the depositary receipt. Changes in foreign currency exchange rates will affect the value of depositary receipts and, therefore, may affect the value of your investment in the Fund. 

Changing Distribution Level Risk. The Fund normally expects to receive income which may include interest, dividends and/or capital gains, depending upon its investments. The distribution amounts paid by the Fund will vary and generally depend on the amount of income the Fund earns (less expenses) on its portfolio holdings, and capital gains or losses it recognizes. A decline in the Fund’s income or net capital gains arising from its investments may reduce its distribution level. 

Geographic Focus Risk. The Fund may be particularly susceptible to risks related to economic, political, regulatory or other events or conditions affecting issuers and countries within the specific geographic regions in which the Fund invests. The Fund’s NAV may be more volatile than the NAV of a more geographically diversified fund. 

■ Asia Pacific Region. A number of countries in the Asia Pacific region are considered underdeveloped or developing, including from a political, economic and/or social perspective, and may have relatively unstable governments and economies based on limited business, industries and/or natural resources or commodities. Events in any one country within the region may impact that country, other countries in the region or the region as a whole. As a result, events in the region will generally have a greater effect on the Fund than if the Fund were more geographically diversified in a region with more developed countries and economies. This could result in increased volatility in the value of the Fund’s investments and losses for the Fund. Continued growth of economies and securities markets in the region will require sustained economic and fiscal discipline, as well as continued commitment to governmental and regulatory reforms. Development also may be influenced by international economic conditions, including those in the United States and Japan, and by world demand for goods or natural resources produced in countries in the Asia Pacific region. Securities markets in the region are generally smaller and have a lower trading volume than those in the United States, which may result in the securities of some companies in the region being less liquid than U.S. or other foreign securities. Some currencies, inflation rates or interest rates in the Asia Pacific region are or can be volatile, and some countries in the region may restrict the flow of money in and out of the country. The risks described under “Emerging Market Securities Risk” and  “Foreign Securities Risk” may be more pronounced due to the Fund’s focus on investments in the region. 

■ Greater China. The Greater China region consists of Hong Kong, The People's Republic of China and Taiwan, among other countries, and the Fund's investments in the region are particularly susceptible to risks in that region. The Hong Kong, Taiwanese, and Chinese economies are dependent on the economies of other countries and can be significantly affected by currency fluctuations and increasing competition from other emerging economies in Asia with lower costs. Adverse events in any one country within the region may impact the other countries in the region or Asia as a whole. As a result, adverse events in the region will generally have a greater effect on the Fund than if the Fund were more geographically diversified, which could result in greater volatility in the Fund’s NAV and losses. Markets in the Greater China region can experience significant volatility due to social, economic, regulatory and political uncertainties. Changes in Chinese government policy and economic growth rates could significantly affect local markets and the entire Greater China region. China has yet to develop comprehensive securities, corporate, or commercial laws, its market is relatively new and less developed, and its economy is experiencing a relative slowdown. Export growth continues to be a major driver of China’s economic growth. As a result, a reduction in spending on Chinese products and services, the institution of additional tariffs or other trade barriers, including as a result of heightened trade tensions between China and the United States, or a downturn in any of the economies of China’s key trading partners may have an adverse impact on the Chinese economy. Many Chinese companies to which the Fund seeks investment exposure use a structure known as a variable interest entity (a VIE) to address Chinese restrictions on direct foreign investment in Chinese companies operating in certain sectors. The Fund’s investment exposure to VIEs may pose additional risks because the Fund’s investment is not made directly in the VIE (the actual Chinese operating company), but rather in a holding company domiciled outside of China (a Holding Company) whose interests in the business of the underlying Chinese operating company (the VIE) are established through contracts rather than through equity ownership. The VIE (which the Fund is restricted from owning under Chinese law) is generally owned by Chinese nationals, and the Holding Company (in which the Fund invests) holds only contractual rights (rather than equity ownership) relating to the VIE, typically including a contractual claim on the VIE's profits. Shares of the Holding Company, in turn, are traded on exchanges outside of China and are available to non-Chinese investors such as the Fund. The VIE structure is a longstanding practice in China but, until recently, was not acknowledged by the Chinese government, creating uncertainty over the possibility that the Chinese government might cease to tolerate VIE structures at any time or impose new restrictions on the structure. In such a scenario, the Chinese operating company could be subject to penalties, including revocation of its business and operating license, or the Holding Company could forfeit its interest in the business of the Chinese operating company. Further, in case of a dispute, the remedies and rights of the Fund may be limited, and such legal uncertainty may be exploited against the interests of the Fund. Control over a VIE may also be jeopardized if a natural person who holds the equity interest in the VIE breaches the terms of the contractual arrangements, is subject to legal proceedings, or if any physical instruments or property of the VIE, such as seals, business registration certificates, financial data and licensing arrangements (sometimes referred to as “chops”), are used without authorization. In the event of such an occurrence, the Fund, as a foreign investor, 

may have little or no legal recourse. In addition to the risk of government intervention, investments through a VIE structure are subject to the risk that the China-based company (or its officers, directors, or Chinese equity owners) may breach the contractual arrangements, or Chinese law changes in a way that adversely affects the enforceability of the arrangements, or the contracts are otherwise not enforceable under Chinese law, in which case a Fund may suffer significant losses on its investments through a VIE structure with little or no recourse available. The Fund will typically have little or no ability to influence the VIE through proxy voting or other means because it is not a VIE owner/shareholder. Foreign companies listed on stock exchanges in the United States, including companies using the VIE structure, could also face delisting or other ramifications for failure to meet the expectations and/or requirements of the SEC, the Public Company Accounting Oversight Board, or other U.S. regulators. Recently, however, China has proposed the adoption of rules which would affirm that VIEs are legally permissible, though there remains significant uncertainty over how these rules will operate. Any of these risks could reduce the liquidity and value of the Fund’s investments in Holding Companies or render them valueless. 

Real Estate-Related Investment Risk. Investments in real estate investment trusts (REITs) and in securities of other companies (wherever organized) principally engaged in the real estate industry subject the Fund to, among other things, risks similar to those of direct investments in real estate and the real estate industry in general. These include risks related to general and local economic conditions, possible lack of availability of financing and changes in interest rates or property values. The value of interests in a REIT may be affected by, among other factors, changes in the value of the underlying properties owned by the REIT, changes in the prospect for earnings and/or cash flow growth of the REIT itself, defaults by borrowers or tenants, market saturation, decreases in market rates for rents, and other economic, political, or regulatory matters affecting the real estate industry, including REITs. REITs may be subject to more abrupt or erratic price movements than the overall securities markets. REITs are also subject to the risk of failing to qualify for favorable tax treatment under the Internal Revenue Code of 1986, as amended. The failure of a REIT to continue to qualify as a REIT for tax purposes can materially and adversely affect its value. Some REITs (especially mortgage REITs) are affected by risks similar to those associated with investments in debt securities including changes in interest rates and the quality of credit extended. 

Quantitative Model Risk. Quantitative models used by the Fund or Index may not be effective in selecting the most favorable securities for the Fund or for inclusion in the Index and may cause the Fund to underperform other investment strategies. Flaws or errors in the quantitative model’s assumptions, design, execution, or data inputs may adversely affect Fund performance. Quantitative models may not perform as expected and may underperform in certain market environments including in stressed or volatile market conditions. There can be no assurance that the use of quantitative models will enable the Fund to achieve its objective. 

Rule 144A and Other Exempted Securities Risk. The Fund may invest in privately placed and other securities or instruments exempt from SEC registration (collectively “private placements”), subject to certain regulatory restrictions. In the U.S. market, private placements are typically sold only to qualified institutional buyers, or qualified purchasers, as applicable. An insufficient number of buyers interested in purchasing private placements at a particular time could adversely affect the marketability of such investments and the Fund might be unable to dispose of them promptly or at reasonable prices, subjecting the Fund to liquidity risk (the risk that it may not be possible for the Fund to liquidate the instrument at an advantageous time or price). The Fund’s holdings of private placements may increase the level of Fund illiquidity if eligible buyers are unable or unwilling to purchase them at a particular time. The Fund may also have to bear the expense of registering the securities for resale and the risk of substantial delays in effecting the registration. Additionally, the purchase price and subsequent valuation of private placements typically reflect a discount, which may be significant, from the market price of comparable securities for which a more liquid market exists. Issuers of Rule 144A eligible securities are required to furnish information to potential investors upon request. However, the required disclosure is much less extensive than that required of public companies and is not publicly available since the offering information is not filed with the SEC. Further, issuers of Rule 144A eligible securities can require recipients of the offering information (such as the Fund) to agree contractually to keep the information confidential, which could also adversely affect the Fund’s ability to dispose of the security. 

Counterparty Risk. Counterparty risk is the risk that a counterparty to a transaction in a financial instrument held by the Fund or by a special purpose or structured vehicle invested in by the Fund may become insolvent or otherwise fail to perform its obligations. As a result, the Fund may obtain no or limited recovery of its investment, and any recovery may be significantly delayed. 

Liquidity Risk. Liquidity risk is the risk associated with any event, circumstance, or characteristic of an investment or market that negatively impacts the Fund’s ability to sell, or realize the proceeds from the sale of, an investment at a desirable time or price. Liquidity risk may arise because of, for example, a lack of marketability of the investment, which means that when seeking to sell its portfolio investments, the Fund could find that selling is more difficult than anticipated, especially during times of high market volatility. Decreases in the number of financial institutions, including banks and broker-dealers, willing to make markets (match up sellers and buyers) in the Fund’s investments or decreases in their capacity or willingness to trade such investments may increase the Fund’s exposure to this risk. The debt market has experienced considerable growth, and financial institutions making markets in instruments purchased and sold by the Fund (e.g., bond dealers) have been subject to increased regulation. The impact of that growth and regulation on the ability and willingness of financial institutions to engage in trading or “making a market” in such instruments remains unsettled. Certain types of investments, such as lower-rated securities or those that are purchased and sold in over-the-counter markets, may be especially subject to liquidity risk. Securities or other assets in which the Fund invests may be traded in the over-the-counter market rather than on an exchange and therefore may be more difficult to purchase or sell at a fair price, which may have a negative impact on the Fund’s performance. Market participants attempting to sell the same or a similar instrument at the same time as the Fund could exacerbate the Fund’s exposure to liquidity risk. The Fund may have to accept a lower selling price for the holding, sell other liquid or more liquid investments that it might otherwise prefer to hold (thereby increasing the proportion of the Fund’s investments in less liquid or illiquid securities), or forego another more appealing investment opportunity. The liquidity of Fund investments may change significantly over time and certain investments that were liquid when purchased by the Fund may later become illiquid, particularly in times of overall economic distress. Changing regulatory, market or other conditions or environments (for example, the interest rate or credit environments) may also adversely affect the liquidity and the price of the Fund's investments. Judgment plays a larger role in valuing illiquid or less liquid investments as compared to valuing liquid or more liquid investments. Price volatility may be higher for illiquid or less liquid investments as a result of, for example, the relatively less frequent pricing of such securities (as compared to liquid or more liquid investments). Generally, the less liquid the market at the time the Fund sells a portfolio investment, the greater the risk of loss or decline of value to the Fund. Overall market liquidity and other factors can lead to an increase in redemptions, which may negatively impact Fund performance and NAV, including, for example, if the Fund is forced to sell investments in a down market. 

Mortgage- and Other Asset-Backed Securities Risk. The value of any mortgage-backed and other asset-backed securities including collateralized debt obligations and collateralized loan obligations, if any, held by the Fund may be affected by, among other things, changes or perceived changes in: interest rates; factors concerning the interests in and structure of the issuer or the originator of the mortgages or other assets; the creditworthiness of the entities that provide any supporting letters of credit, surety bonds or other credit enhancements; or the market's assessment of the quality of underlying assets. Payment of principal and interest on some mortgage-backed securities (but not the market value of the securities themselves) may be guaranteed by the full faith and credit of a particular U.S. Government agency, authority, enterprise or instrumentality, and some, but not all, are also insured or guaranteed by the U.S. Government. Mortgage-backed securities issued by non-governmental issuers (such as commercial banks, savings and loan institutions, private mortgage insurance companies, mortgage bankers and other secondary market issuers) may entail greater risk than obligations guaranteed by the U.S. Government. Mortgage- and other asset-backed securities are subject to liquidity risk and prepayment risk. A decline or flattening of housing values may cause delinquencies in mortgages (especially sub-prime or non-prime mortgages) underlying mortgage-backed securities and thereby adversely affect the ability of the mortgage-backed securities issuer to make principal and/or interest payments to mortgage-backed securities holders, including the Fund. Rising or high interest rates tend to extend the duration of mortgage- and other asset-backed securities, making their prices more volatile and more sensitive to changes in interest rates. 

LIBOR Replacement Risk. London Inter-Bank Offered Rate (LIBOR), which is used extensively in the U.S. and globally as a benchmark or reference rate for various commercial and financial contracts, among other “inter-bank offered” reference rates, is in the process of being discontinued as a global reference rate. The elimination of LIBOR may adversely affect the interest rates on, and value of, certain Fund investments that are tied to LIBOR. Such investments may include derivatives, and other assets or liabilities. On July 27, 2017, the U.K. Financial Conduct Authority (FCA) announced that it intended to stop compelling or inducing banks to submit LIBOR rates after 2021. The FCA and the ICE Benchmark Administration have since announced that a majority of U.S. dollar LIBOR settings will cease publication after June 30, 2023. A subset of non-U.S. dollar LIBOR settings are continuing to be published on a “synthetic” basis and it is possible that a subset of U.S. dollar LIBOR settings will also be published after June 30, 2023 on a “synthetic” basis. Any such publications are, or would be considered, non-representative of the underlying market. The U.S. Federal Reserve, based on the recommendations of the New York Federal Reserve’s Alternative Reference Rate Committee (comprised of major derivative market participants and their regulators), has begun publishing and promoting SOFR as the alternative reference rate to U.S. dollar LIBOR. Proposals for alternative reference rates for other currencies have also been announced or have already begun publication. Markets are slowly developing in response to these new reference rates. Uncertainty related to the liquidity impact of the change in rates, and how to appropriately adjust these rates at the time of transition, poses risks for the Fund. The effect of the discontinuation of LIBOR on the Fund will depend on, among other things, (1) existing fallback or termination provisions in individual contracts and (2) whether, how, and when industry participants develop and adopt new reference rates and fallbacks for both legacy and new instruments and contracts. The discontinuation of LIBOR could have a significant impact on the financial markets in general and may also present heightened risk to market participants, including public companies, investment advisers, investment companies, and broker-dealers. The risks associated with this discontinuation and transition will be exacerbated if the work necessary to effect an orderly transition to an alternative reference rate is not completed in a timely manner. For example, current information technology systems may be unable to accommodate new instruments and rates with features that differ from LIBOR. Accordingly, it is difficult to predict the full impact of the transition away from LIBOR on the Fund until new reference rates and fallbacks for both legacy and new products, instruments and contracts are commercially accepted and market practices become more settled. 

Frequent Trading Risk. The portfolio managers may actively and frequently trade investments in the Fund's portfolio to carry out its investment strategies . Frequent trading of investments increases the possibility that the Fund, as relevant, will realize taxable capital gains (including short-term capital gains, which are generally taxable to shareholders at higher rates than long-term capital gains for U.S. federal income tax purposes), which could reduce the Fund's after-tax return. Frequent trading can also mean higher brokerage and other transaction costs, which could reduce the Fund's return. The trading costs and tax effects associated with portfolio turnover may adversely affect the Fund’s performance. 

Leverage Risk. Leverage occurs when the Fund increases its assets available for investment using borrowings, derivatives, or similar instruments or techniques. Use of leverage can produce volatility and may exaggerate changes in the NAV of Fund shares and in the return on the Fund’s portfolio, which may increase the risk that the Fund will lose more than it has invested. The use of leverage may cause the Fund to liquidate portfolio positions when it may not be advantageous to do so to satisfy its obligations or to meet any required asset segregation or position coverage requirements. Futures contracts, options on futures contracts, forward contracts and other derivatives can allow the Fund to obtain large investment exposures in return for meeting relatively small margin requirements. As a result, investments in those transactions may be highly leveraged. If the Fund uses leverage, through the purchase of particular instruments such as derivatives, the Fund may experience capital losses that exceed the net assets of the Fund. Leverage can create an interest expense that may lower the Fund's overall returns. Leverage presents the opportunity for increased net income and capital gains, but may also exaggerate the Fund's volatility and risk of loss. There can be no guarantee that a leveraging strategy will be successful. 

Stripped Mortgage-Backed Securities Risk. Stripped mortgage-backed securities are a type of mortgage-backed security that receive differing proportions of the interest and principal payments from the underlying assets. Generally, there are two classes of stripped mortgage-backed securities: Interest Only (IO) and Principal Only (PO). IOs entitle the holder to receive distributions consisting of all or a portion of the interest on the underlying pool of 

mortgage loans or mortgage-backed securities. POs entitle the holder to receive distributions consisting of all or a portion of the principal of the underlying pool of mortgage loans or mortgage-backed securities. The cash flows and yields on IOs and POs are extremely sensitive to the rate of principal payments (including prepayments) on the underlying mortgage loans or mortgage-backed securities. A rapid rate of principal payments may adversely affect the yield to maturity of IOs. A slow rate of principal payments may adversely affect the yield to maturity of POs. If prepayments of principal are greater than anticipated, an investor in IOs may incur substantial losses. If prepayments of principal are slower than anticipated, the yield on a PO will be affected more severely than would be the case with a traditional mortgage-backed security. 

The Fund is subject indirectly to the following risks of Portfolio Funds seeking returns that correspond to a stated market index (the Index). 

Passive Investment Risk. The Fund is not “actively” managed and may be affected by a general decline in market segments related to its underlying index. The Fund invests in securities or instruments included in, or believed by the Portfolio Fund’s Investment Manager to be representative of, its underlying index, regardless of their investment merits. The Fund does not seek temporary defensive positions when markets decline or appear overvalued. 

Index Fund Risk. An index fund seeks to track the performance of the Index by using indexing strategies and, therefore, would not necessarily sell a security because the security’s issuer was in financial trouble or defaulted, or whose credit rating was downgraded, unless that security was removed from the Index. The decision of whether to remove a security from an index is made by an independent index provider who is not affiliated with the Fund or the Investment Manager or its affiliates. 

Index Methodology Risk. An index fund seeks performance that corresponds to the performance of the Index. There is no guarantee or assurance that the Index will achieve high, or even positive, returns. The Index may underperform more traditional indices. In turn, the Fund could lose value while other indices or measures of market performance increase in value or performance. In addition, the Fund may be subject to the risk that the index provider may not follow its stated methodology for construction of the Index or may make errors in Index computation, construction and rebalancing despite any index provider procedures designed to prevent such occurrences and despite due diligence conducted by the investment manager or the index provider. Errors may result in a negative performance impact to the Fund and its shareholders. 

Correlation/Tracking Error Risk. An index fund’s value will generally decline when the performance of the securities in the Index declines. A number of factors may affect the Fund’s ability to achieve a high degree of correlation with the Index, and there is no guarantee that the Fund will achieve a high degree of correlation. Failure to achieve such degree of correlation may prevent the Fund from achieving its investment objective. The factors that may adversely affect the Fund’s correlation with the Index include the size of the Fund’s portfolio, fees, expenses, transaction costs, income items, valuation methodology, accounting standards, the effectiveness of sampling techniques (if applicable), changes in the Index and disruptions or illiquidity in the markets for the securities in which the Fund invests. While the Fund typically attempts to track the performance of the Index by investing all, or substantially all, of its assets in the securities that make up the Index in approximately the same proportion as their weighting in the Index, at times, the Fund may not have investment exposure to all securities in the Index, or its weighting of investment exposure to securities may be different from that of the Index. In addition, the Fund may invest in securities not included in the Index. The Fund may take or refrain from taking investment positions for various reasons, such as tax efficiency purposes, or to comply with regulatory restrictions, which may negatively affect the Fund’s correlation with the Index. The Fund may also be subject to large movements of assets into and out of the Fund, potentially resulting in the Fund being over- or under-exposed to certain securities comprising the Index and may be impacted by Index reconstitutions and Index rebalancing events. Holding cash balances may detract from the Fund’s ability to track the Index. In addition, the Fund’s NAV may deviate from the Index if the Fund fair values a portfolio security at a price other than the price used by the Index for that security. The Fund also bears management and other expenses and transaction costs in trading securities, which the Index does not bear. Accordingly, the Fund’s performance will likely fail to match the performance of the Index, after taking expenses into account. Any of these factors could decrease correlation between the performance of the Fund and the Index and may hinder the Fund’s ability to meet its investment objective. It is not possible to invest directly in an index. 

The Fund is subject indirectly to the following risks of Portfolio Funds that are exchange-traded funds seeking investment results that, before fees and expenses, closely correspond to the performance of a stated index (the Index). 

Exchange-Traded Fund (ETF) Risk. ETFs are subject to, among other risks, tracking risk and passive and, in some cases, active investment risk. An ETF’s share price may not track its specified market index (if any) and may trade below its NAV. Certain ETFs use a “passive” investment strategy and do not take defensive positions in volatile or declining markets. Other ETFs are actively managed ETFs (i.e., they do not track a particular benchmark), which are subject to active management risk. An active secondary market in ETF shares may not develop or be maintained and may be halted or interrupted due to actions by its listing exchange, unusual market conditions or other reasons. There can be no assurance that an ETF’s shares will continue to be listed on an active exchange. In addition, shareholders bear expenses incurred through ownership of the ETF. There is a risk that ETFs may terminate due to extraordinary events. For example, any of the service providers to ETFs, such as the trustee or sponsor, may close or otherwise fail to perform their obligations to the ETF, and the ETF may not be able to find a substitute service provider. Also, certain ETFs may be dependent upon licenses to use various indexes as a basis for determining their compositions and/or otherwise to use certain trade names. If these licenses are terminated, the ETFs may also terminate. In addition, an ETF may terminate if its net assets fall below a certain amount. 

Secondary Market Trading Risk. Investors buying or selling Fund shares will pay brokerage commissions or other charges imposed by brokers as determined by that broker. Brokerage commissions are often a fixed amount and may be a significant proportional cost for investors seeking to buy or sell relatively small amounts of shares. In addition, secondary market investors will also incur the cost of the difference between the price that an investor is willing to pay for Fund shares (the bid price) and the price at which an investor is willing to sell Fund shares (the ask price). This difference in bid and ask prices is often referred to as the “spread” or “bid/ask spread.” The bid/ask spread varies over time for Fund shares based on trading volume and market liquidity, and is generally lower if the Fund’s shares have more trading volume and market liquidity and higher if the Fund’s shares have little trading volume and market liquidity. Further, increased market volatility may cause increased bid/ask spreads. 

Market Price Relative to NAV Risk. Shares of the Fund may trade at prices that vary from Fund NAV. Shares of the Fund are listed for trading on the Exchange (as defined in the Portfolio Fund's prospectus) and are bought and sold in the secondary market at market prices that may differ, in some cases significantly, from their NAV. The NAV of the Fund will generally fluctuate with changes in the market value of the Fund’s holdings. The market prices of shares, however, will generally fluctuate in response to changes in NAV, as well as the relative supply of, and demand for, Fund shares on the Exchange. The Investment Manager cannot predict whether Fund shares will trade below, at or above their NAV. Price differences may result because of, among other factors, supply and demand forces in the secondary trading market for Fund shares. It is expected that these forces generally will be closely related to, but not identical to, the same forces influencing the prices of the Fund’s holdings. In this regard, if a shareholder purchases Fund shares at a time when the market price is at a premium to the NAV or sells shares at a time when the market price is at a discount to the NAV, the shareholder may sustain losses. Different investment strategies or techniques, including those intended to be defensive in nature, including, as examples, stop loss orders to sell an ETF’s shares in the secondary market during negative market events or conditions, such as a “flash crash” or other market disruptions, may not work as intended and may produce significant losses to investors. Investors should consult their financial intermediary prior to using any such investment strategies or techniques, or before investing in the Fund. 

Authorized Participant Concentration Risk. Only an Authorized Participant (as defined in the Portfolio Fund's prospectus) may engage in creation or redemption transactions directly with the Fund. The Fund has a limited number of institutions that may act as Authorized Participants, none of which are or will be obligated to engage in creation or redemption transactions. To the extent that these institutions exit the business or are unable or unwilling to proceed with creation and/or redemption orders with respect to the Fund and no other Authorized Participant is able or willing to step forward to create or redeem Creation Units (as defined in the Portfolio Fund's prospectus), Fund shares may trade at a discount to NAV and possibly face trading halts and/or delisting from the Exchange. This risk is heightened in times of market stress, including at both the Fund share level and at the Fund holdings level. 

Fund Shares Liquidity Risk. Although the Fund’s shares are listed on the Exchange, there can be no assurance that an active, liquid or otherwise orderly trading market for shares will be established or maintained by market makers or Authorized Participants, particularly in times of stressed market conditions. There is no guarantee that the Fund will be able to attract market makers and Authorized Participants. There is no obligation for market makers to make a market in the Fund’s shares or for Authorized Participants to submit purchase or redemption orders for creation units. Accordingly, if such parties determine not to perform their respective functions, this could, such as during times of market stress, in turn, lead to variances between the market price of the Fund’s shares and the underlying value of those shares and bid/ask spreads could widen. Trading in Fund shares on the Exchange also may be disrupted or even halted due to market conditions or for reasons that, in the view of the Exchange, make trading in Fund shares inadvisable. In addition, trading in Fund shares on the Exchange may be subject to trading halts caused by extraordinary market volatility pursuant to the Exchange “circuit breaker” rules. There also can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund’s shares will continue to be met or will remain unchanged. 

Early/Late Close/Trading Halt Risk.  An exchange or market may close early, close late or issue trading halts on specific securities, or the ability to buy or sell certain securities may be restricted, which may result in the Fund being unable to buy or sell these securities. In these circumstances, the Fund may be unable to rebalance its portfolio, may be unable to accurately price its investments, may incur substantial trading losses and/or may be prevented from sufficiently tracking the performance of the Index. 

Concentration Risk. The Fund will concentrate its investments in issuers conducting business in a related group of industries within a sector(s) to approximately the same extent as the Index. Issuers in the same industry or group of industries or sector may be similarly affected by economic, regulatory, political or market events or conditions, which may make the Fund more vulnerable to unfavorable developments in that sector than funds that invest more broadly. Generally, the more broadly a fund diversifies its investments, the more it spreads risk and potentially reduces the risks of loss and volatility. 

Risk Lose Money [Text]

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There is no assurance that the Fund will achieve its investment objective and you may lose money.

Risk Not Insured Depository Institution [Text]

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An investment in the Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency.

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Performance Information

Performance Narrative [Text Block]

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The following bar chart and table show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. The bar chart shows how the Fund’s Class Inst share performance has varied for each full calendar year shown. The table below the bar chart compares the Fund’s returns for the periods shown with those of two broad-based indexes: the S&P 500^® Index, the Fund’s primary benchmark for equity securities, and the Bloomberg U.S. Aggregate Bond Index, the Fund’s primary benchmark for debt securities. The table below also compares the Fund's returns with a secondary, custom index, the Blended Benchmark. The S&P 500^® Index tracks the performance of 500 widely held, large-capitalization U.S. stocks. The Bloomberg U.S. Aggregate Bond Index is a market value-weighted index that tracks the daily price, coupon, pay-downs, and total return performance of fixed-rate, publicly placed, dollar-denominated, and non-convertible investment grade debt issues with at least $250 million par amount outstanding and with at least one year to final maturity. The Blended Benchmark was established by the Investment Manager to show how the Fund’s performance compares to an equally weighted custom composite of the Fund’s primary equity and primary debt benchmarks, the S&P 500^® Index and the Bloomberg U.S. Aggregate Bond Index, respectively. The percentage of the Fund’s assets allocated to underlying stock and bond Portfolio Funds will vary, and accordingly the composition of the Fund’s portfolio will not always reflect the composition of the Blended Benchmark. 

The performance of one or more share classes shown in the Average Annual Total Returns table below includes the Fund’s Class Inst share returns (adjusted to reflect the higher class-related operating expenses of such classes, where applicable) for periods prior to the indicated inception date of such share classes. Except for differences in fees and expenses, all share classes of the Fund would have substantially similar annual returns because all share classes of the Fund invest in the same portfolio of securities. 

The after-tax returns shown in the Average Annual Total Returns table below are calculated using the highest historical individual U.S. federal marginal income tax rates in effect during the period indicated in the table and do not reflect the impact of state, local or foreign taxes. Your actual after-tax returns will depend on your personal tax 

situation and may differ from those shown in the table. In addition, the after-tax returns shown in the table do not apply to shares held in tax-advantaged accounts such as 401(k) plans or Individual Retirement Accounts (IRAs). The after-tax returns are shown only for Class Inst shares and will vary for other share classes. 

The Fund’s performance prior to May 2018 reflects returns achieved following a principal investment strategy with a single form of asset allocation table. While the Fund now follows a principal investment strategy with two potential forms of asset allocation tables, as described above in the Principal Investment Strategies section, the form of the Fund’s currently effective asset allocation table was in place from the Fund’s inception in 2002 through April 30, 2020. The Fund's performance prior to May 1, 2020 and after April 30, 2021 reflects the current form of allocation table. The Fund's performance from May 1, 2020 through April 30, 2021 reflects a different form of asset allocation table. 

The Fund’s past performance (before and after taxes) is no guarantee of how the Fund will perform in the future. Updated performance information can be obtained by calling toll-free 800.345.6611 or visiting columbiathreadneedleus.com. 

Performance Information Illustrates Variability of Returns [Text]

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The following bar chart and table show you how the Fund has performed in the past, and can help you understand the risks of investing in the Fund. The bar chart shows how the Fund’s Class Inst share performance has varied for each full calendar year shown. The table below the bar chart compares the Fund’s returns for the periods shown with those of two broad-based indexes: the S&P 500® Index, the Fund’s primary benchmark for equity securities, and the Bloomberg U.S. Aggregate Bond Index, the Fund’s primary benchmark for debt securities. The table below also compares the Fund's returns with a secondary, custom index, the Blended Benchmark.

Performance Additional Market Index [Text]

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The Blended Benchmark was established by the Investment Manager to show how the Fund’s performance compares to an equally weighted custom composite of the Fund’s primary equity and primary debt benchmarks, the S&P 500® Index and the Bloomberg U.S. Aggregate Bond Index, respectively. The percentage of the Fund’s assets allocated to underlying stock and bond Portfolio Funds will vary, and accordingly the composition of the Fund’s portfolio will not always reflect the composition of the Blended Benchmark. 

Performance Availability Phone [Text]

rr_PerformanceAvailabilityPhone

800.345.6611

Performance Availability Website Address [Text]

rr_PerformanceAvailabilityWebSiteAddress

columbiathreadneedleus.com

Performance Past Does Not Indicate Future [Text]

rr_PerformancePastDoesNotIndicateFuture

The Fund’s past performance (before and after taxes) is no guarantee of how the Fund will perform in the future.

Bar Chart [Heading]

rr_BarChartHeading

Year by Year Total Return (%) as of December 31 Each Year*

Bar Chart Closing [Text Block]

rr_BarChartClosingTextBlock

Best and Worst Quarterly Returns During the Period Shown in the Bar Chart Best 2nd Quarter 2020 13.30% Worst 3rd Quarter 2015 -2.27%

Performance Table Heading

rr_PerformanceTableHeading

 Average Annual Total Returns After Applicable Sales Charges (for periods ended December 31, 2021)

Performance Table Uses Highest Federal Rate

rr_PerformanceTableUsesHighestFederalRate

The after-tax returns shown in the Average Annual Total Returns table below are calculated using the highest historical individual U.S. federal marginal income tax rates in effect during the period indicated in the table and do not reflect the impact of state, local or foreign taxes.

Performance Table Not Relevant to Tax Deferred

rr_PerformanceTableNotRelevantToTaxDeferred

In addition, the after-tax returns shown in the table do not apply to shares held in tax-advantaged accounts such as 401(k) plans or Individual Retirement Accounts (IRAs).

Performance Table One Class of after Tax Shown [Text]

rr_PerformanceTableOneClassOfAfterTaxShown

The after-tax returns are shown only for Class Inst shares and will vary for other share classes.

Columbia Thermostat Fund | Class A

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

5.75%

Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)

rr_MaximumDeferredSalesChargeOverOther

1.00%

^[1]

Management fees

rr_ManagementFeesOverAssets

0.10%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

0.25%

Other expenses

rr_OtherExpensesOverAssets

0.19%

Acquired fund fees and expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.36%

Total annual Fund operating expenses

rr_ExpensesOverAssets

0.90%

^[2]

Fee waivers and/or expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.04%)

^[3]

Total annual Fund operating expenses after fee waivers and/or expense reimbursements

rr_NetExpensesOverAssets

0.86%

Expenses Deferred Charges [Text Block]

rr_ExpensesDeferredChargesTextBlock

This charge is imposed on certain investments of between $1 million and $50 million redeemed within 18 months after purchase, as follows: 1.00% if redeemed within 12 months after purchase, and 0.50% if redeemed more than 12, but less than 18, months after purchase, with certain limited exceptions.

1 year

rr_ExpenseExampleYear01

$ 658

3 years

rr_ExpenseExampleYear03

842

5 years

rr_ExpenseExampleYear05

1,041

10 years

rr_ExpenseExampleYear10

1,616

1 year

rr_ExpenseExampleNoRedemptionYear01

658

3 years

rr_ExpenseExampleNoRedemptionYear03

842

5 years

rr_ExpenseExampleNoRedemptionYear05

1,041

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 1,616

1 Year

rr_AverageAnnualReturnYear01

0.04%

5 Years

rr_AverageAnnualReturnYear05

9.33%

10 Years

rr_AverageAnnualReturnYear10

7.83%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Mar. 03, 2003

Columbia Thermostat Fund | Class C

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)

rr_MaximumDeferredSalesChargeOverOther

1.00%

^[4]

Management fees

rr_ManagementFeesOverAssets

0.10%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

1.00%

Other expenses

rr_OtherExpensesOverAssets

0.19%

Acquired fund fees and expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.36%

Total annual Fund operating expenses

rr_ExpensesOverAssets

1.65%

^[2]

Fee waivers and/or expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.04%)

^[3]

Total annual Fund operating expenses after fee waivers and/or expense reimbursements

rr_NetExpensesOverAssets

1.61%

Expenses Deferred Charges [Text Block]

rr_ExpensesDeferredChargesTextBlock

This charge applies to redemptions within 12 months after purchase, with certain limited exceptions.

1 year

rr_ExpenseExampleYear01

$ 264

3 years

rr_ExpenseExampleYear03

516

5 years

rr_ExpenseExampleYear05

893

10 years

rr_ExpenseExampleYear10

1,751

1 year

rr_ExpenseExampleNoRedemptionYear01

164

3 years

rr_ExpenseExampleNoRedemptionYear03

516

5 years

rr_ExpenseExampleNoRedemptionYear05

893

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 1,751

1 Year

rr_AverageAnnualReturnYear01

4.47%

5 Years

rr_AverageAnnualReturnYear05

9.81%

10 Years

rr_AverageAnnualReturnYear10

7.66%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Mar. 03, 2003

Columbia Thermostat Fund | Class Inst

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)

rr_MaximumDeferredSalesChargeOverOther

none

Management fees

rr_ManagementFeesOverAssets

0.10%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.19%

Acquired fund fees and expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.36%

Total annual Fund operating expenses

rr_ExpensesOverAssets

0.65%

^[2]

Fee waivers and/or expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.04%)

^[3]

Total annual Fund operating expenses after fee waivers and/or expense reimbursements

rr_NetExpensesOverAssets

0.61%

1 year

rr_ExpenseExampleYear01

$ 62

3 years

rr_ExpenseExampleYear03

204

5 years

rr_ExpenseExampleYear05

358

10 years

rr_ExpenseExampleYear10

807

1 year

rr_ExpenseExampleNoRedemptionYear01

62

3 years

rr_ExpenseExampleNoRedemptionYear03

204

5 years

rr_ExpenseExampleNoRedemptionYear05

358

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 807

2012

rr_AnnualReturn2012

13.69%

^[5]

2013

rr_AnnualReturn2013

9.30%

^[5]

2014

rr_AnnualReturn2014

5.57%

^[5]

2015

rr_AnnualReturn2015

0.33%

^[5]

2016

rr_AnnualReturn2016

4.72%

^[5]

2017

rr_AnnualReturn2017

5.52%

^[5]

2018

rr_AnnualReturn2018

0.12%

^[5]

2019

rr_AnnualReturn2019

15.14%

^[5]

2020

rr_AnnualReturn2020

29.63%

^[5]

2021

rr_AnnualReturn2021

6.42%

^[5]

Year to Date Return, Label

rr_YearToDateReturnLabel

Year to Date return

Bar Chart, Year to Date Return, Date

rr_BarChartYearToDateReturnDate

Mar. 31, 2022

Bar Chart, Year to Date Return

rr_BarChartYearToDateReturn

(5.87%)

Highest Quarterly Return, Label

rr_HighestQuarterlyReturnLabel

Best

Highest Quarterly Return, Date

rr_BarChartHighestQuarterlyReturnDate

Jun. 30, 2020

Highest Quarterly Return

rr_BarChartHighestQuarterlyReturn

13.30%

Lowest Quarterly Return, Label

rr_LowestQuarterlyReturnLabel

Worst

Lowest Quarterly Return, Date

rr_BarChartLowestQuarterlyReturnDate

Sep. 30, 2015

Lowest Quarterly Return

rr_BarChartLowestQuarterlyReturn

(2.27%)

1 Year

rr_AverageAnnualReturnYear01

6.42%

5 Years

rr_AverageAnnualReturnYear05

10.91%

10 Years

rr_AverageAnnualReturnYear10

8.75%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 25, 2002

Columbia Thermostat Fund | Class Adv

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)

rr_MaximumDeferredSalesChargeOverOther

none

Management fees

rr_ManagementFeesOverAssets

0.10%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.19%

Acquired fund fees and expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.36%

Total annual Fund operating expenses

rr_ExpensesOverAssets

0.65%

^[2]

Fee waivers and/or expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.04%)

^[3]

Total annual Fund operating expenses after fee waivers and/or expense reimbursements

rr_NetExpensesOverAssets

0.61%

1 year

rr_ExpenseExampleYear01

$ 62

3 years

rr_ExpenseExampleYear03

204

5 years

rr_ExpenseExampleYear05

358

10 years

rr_ExpenseExampleYear10

807

1 year

rr_ExpenseExampleNoRedemptionYear01

62

3 years

rr_ExpenseExampleNoRedemptionYear03

204

5 years

rr_ExpenseExampleNoRedemptionYear05

358

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 807

1 Year

rr_AverageAnnualReturnYear01

6.43%

5 Years

rr_AverageAnnualReturnYear05

10.91%

10 Years

rr_AverageAnnualReturnYear10

8.74%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Nov. 08, 2012

Columbia Thermostat Fund | Class Inst2

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)

rr_MaximumDeferredSalesChargeOverOther

none

Management fees

rr_ManagementFeesOverAssets

0.10%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.14%

Acquired fund fees and expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.36%

Total annual Fund operating expenses

rr_ExpensesOverAssets

0.60%

^[2]

Fee waivers and/or expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.04%)

^[3]

Total annual Fund operating expenses after fee waivers and/or expense reimbursements

rr_NetExpensesOverAssets

0.56%

1 year

rr_ExpenseExampleYear01

$ 57

3 years

rr_ExpenseExampleYear03

188

5 years

rr_ExpenseExampleYear05

331

10 years

rr_ExpenseExampleYear10

746

1 year

rr_ExpenseExampleNoRedemptionYear01

57

3 years

rr_ExpenseExampleNoRedemptionYear03

188

5 years

rr_ExpenseExampleNoRedemptionYear05

331

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 746

1 Year

rr_AverageAnnualReturnYear01

6.53%

5 Years

rr_AverageAnnualReturnYear05

10.95%

10 Years

rr_AverageAnnualReturnYear10

8.78%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Nov. 08, 2012

Columbia Thermostat Fund | Class Inst3

Risk/Return:

rr_RiskReturnAbstract

Maximum sales charge (load) imposed on purchases (as a % of offering price)

rr_MaximumSalesChargeImposedOnPurchasesOverOfferingPrice

none

Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)

rr_MaximumDeferredSalesChargeOverOther

none

Management fees

rr_ManagementFeesOverAssets

0.10%

Distribution and/or service (12b-1) fees

rr_DistributionAndService12b1FeesOverAssets

none

Other expenses

rr_OtherExpensesOverAssets

0.11%

Acquired fund fees and expenses

rr_AcquiredFundFeesAndExpensesOverAssets

0.36%

Total annual Fund operating expenses

rr_ExpensesOverAssets

0.57%

^[2]

Fee waivers and/or expense reimbursements

rr_FeeWaiverOrReimbursementOverAssets

(0.05%)

^[3]

Total annual Fund operating expenses after fee waivers and/or expense reimbursements

rr_NetExpensesOverAssets

0.52%

1 year

rr_ExpenseExampleYear01

$ 53

3 years

rr_ExpenseExampleYear03

178

5 years

rr_ExpenseExampleYear05

313

10 years

rr_ExpenseExampleYear10

709

1 year

rr_ExpenseExampleNoRedemptionYear01

53

3 years

rr_ExpenseExampleNoRedemptionYear03

178

5 years

rr_ExpenseExampleNoRedemptionYear05

313

10 years

rr_ExpenseExampleNoRedemptionYear10

$ 709

1 Year

rr_AverageAnnualReturnYear01

6.52%

5 Years

rr_AverageAnnualReturnYear05

11.00%

10 Years

rr_AverageAnnualReturnYear10

8.82%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Nov. 08, 2012

Columbia Thermostat Fund | returns after taxes on distributions | Class Inst

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

2.26%

5 Years

rr_AverageAnnualReturnYear05

8.36%

10 Years

rr_AverageAnnualReturnYear10

6.82%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 25, 2002

Columbia Thermostat Fund | returns after taxes on distributions and sale of Fund shares | Class Inst

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

5.30%

5 Years

rr_AverageAnnualReturnYear05

7.76%

10 Years

rr_AverageAnnualReturnYear10

6.34%

Share Class Inception Date

rr_AverageAnnualReturnInceptionDate

Sep. 25, 2002

Columbia Thermostat Fund | Blended Benchmark (Secondary Benchmark; an equally weighted custom composite of the Fund's primary benchmarks for equity and debt securities, established by the Investment Manager; reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

12.80%

5 Years

rr_AverageAnnualReturnYear05

11.12%

10 Years

rr_AverageAnnualReturnYear10

9.78%

Columbia Thermostat Fund | S&P 500® Index (Primary Equity Benchmark; reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

28.71%

5 Years

rr_AverageAnnualReturnYear05

18.47%

10 Years

rr_AverageAnnualReturnYear10

16.55%

Columbia Thermostat Fund | Bloomberg U.S. Aggregate Bond Index (Primary Debt Benchmark; reflects no deductions for fees, expenses or taxes)

Risk/Return:

rr_RiskReturnAbstract

1 Year

rr_AverageAnnualReturnYear01

(1.54%)

5 Years

rr_AverageAnnualReturnYear05

3.57%

10 Years

rr_AverageAnnualReturnYear10

2.90%

[1] This charge is imposed on certain investments of between $1 million and $50 million redeemed within 18 months after purchase, as follows: 1.00% if redeemed within 12 months after purchase, and 0.50% if redeemed more than 12, but less than 18, months after purchase, with certain limited exceptions.

[2] “Total annual Fund operating expenses” include acquired fund (Portfolio Fund) fees and expenses (expenses the Fund incurs indirectly through its investments in other funds) and may be higher than the ratio of expenses to average net assets shown in the Financial Highlights section of this prospectus because the ratio of expenses to average net assets does not include Portfolio Fund (acquired fund) fees and expenses.

[3] Columbia Wanger Asset Management, LLC (the Investment Manager) has contractually agreed to waive fees and reimburse certain expenses of the Fund, through April 30, 2023, so that ordinary operating expenses (excluding transaction costs and certain other investment-related expenses, interest and fees on borrowings and expenses associated with the Fund’s investment in other investment companies, including the Portfolio Funds) do not exceed the annual rates of 0.50% for Class A shares, 0.25% for Class Adv shares, 1.25% for Class C shares, 0.25% for Class Inst shares, 0.20% for Class Inst2 shares and 0.16% for Class Inst3 shares. This arrangement may only be amended or terminated with approval from the Fund's Board of Trustees and the Investment Manager.

[4] This charge applies to redemptions within 12 months after purchase, with certain limited exceptions.

[5] Year to Date return as of March 31, 2022: -5.87%