Investment Objective

Fees and Expenses of the Fund

Shareholder Fees (fees paid directly from your investment)

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Example

Expense Example (Columbia Acorn Emerging Markets Fund℠) (USD $)	1 Year	3 Years
Class R4 Shares	163	2,711
Class R5 Shares	149	2,687

Portfolio Turnover

Principal Investment Strategies

Principal Risks

Performance Information

The Fund seeks long-term capital appreciation.

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees (Columbia Acorn European Fund℠)	Class R5 Shares
Maximum sales charge (load) imposed on purchases, as a % of offering price	none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or net asset value	none

Annual Fund Operating Expenses (Columbia Acorn European Fund℠)		Class R5 Shares
Management fees		1.19%
Distribution and/or service (Rule 12b-1) fees		none
Other expenses	^[1]	17.83%
Total annual Fund operating expenses		19.02%
Fee waivers and/or reimbursements	^[2]	(17.66%)
Total annual Fund operating expenses after fee waivers and/or reimbursements		1.36%

[1]

Other expenses are based on estimated amounts for the current fiscal year.

[2]

Columbia Wanger Asset Management, LLC (the Investment Manager) has contractually agreed to waive fees and reimburse certain expenses of the Fund so that the ordinary operating expenses (excluding interest and fees on borrowings and expenses associated with the Fund's investment in other investment companies, if any) do not exceed the annual rate of 1.36% of the Fund's average daily net assets attributable to Class R5 shares, through November 8, 2013. The Investment Manager may recoup any fees waived and/or expenses reimbursed with respect to any share class of the Fund for a one-year period following the date of such fee waiver and/or reimbursement if such recovery does not cause the Fund's ordinary operating expenses (excluding interest and fees on borrowings and expenses associated with the Fund's investment in other investment companies, if any) to exceed the annual rates set forth in this prospectus, or to exceed such annual rate as may be in place at the time of the recoupment, whichever is less. This expense arrangement may only be modified or amended with approval from all parties to such arrangements, including the Fund and the Investment Manager.

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 Class R5 shares of the Fund 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 table above.

Since the waivers and/or reimbursements shown in the Annual Fund Operating Expenses table above expire on November 8, 2013, they are only reflected in the 1 year example and the first year of the 3 year example.

Based on the assumptions listed above, your costs would be:

Remember this is an example only. Your actual costs may be higher or lower.

The Fund pays 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 17% of the average value of its portfolio.

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), including up to 10% of its total assets in companies in Russia and the Ukraine. 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 (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 under $5 billion at the time of investment. However, if the Fund's investments in such companies represent less than a majority of its net assets, the Fund may continue to hold and to make additional investments in an existing company in its portfolio even if that company's capitalization has grown to exceed $5 billion. Except as noted above, under normal circumstances, the Fund may invest in other companies with market capitalizations above $5 billion, provided that immediately after that investment a majority of its net assets would be invested in companies with market capitalizations under $5 billion.

Columbia Wanger Asset Management, LLC, the Fund's investment adviser (the Investment Manager), believes that stocks of companies with market capitalizations under $5 billion, 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 that give the company 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.

Investment Strategy Risk – The Fund's manager uses the principal investment strategies and other investment strategies to seek to achieve the Fund's investment objective. There is no assurance that the Fund will achieve its investment objective. Investment decisions may not produce the expected returns, may cause the Fund's shares to lose value or may cause the Fund to underperform other funds with similar investment objectives.

Market Risk – Market risk refers to the possibility that the market values of securities that the Fund holds will fall, sometimes rapidly or unpredictably, or fail to rise. Security values may fall because of factors affecting individual companies, industries or sectors, or the markets as a whole, reducing the value of an investment in the Fund. Accordingly, an investment in the Fund could lose money over short or even long periods, or fail to increase in value. The market values of the securities the Fund holds also can be affected by changes or perceived changes in U.S. or foreign economies and financial markets, and the liquidity of these securities, among other factors. In general, equity securities tend to have greater price volatility than debt securities.

Smaller Company Securities Risk – Securities of small- or mid-capitalization companies ("smaller companies") can, in certain circumstances, have a higher potential for gains than securities of large-capitalization companies but may also have more risk. For example, smaller companies may be more vulnerable to market downturns and adverse business or economic events than larger, more established companies because they may have more limited financial resources and business operations. These companies are also more likely than large-capitalization companies ("larger companies") to have more limited product lines and operating histories and to depend on smaller management teams. Their securities may trade less frequently and in smaller volumes and may be less liquid and fluctuate more sharply in value than securities of larger companies. In cases where the Fund takes significant positions in smaller companies with limited trading volumes, the liquidation of those positions, particularly in a distressed market, could be prolonged and result in investment losses. In addition, some smaller 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 in a broadly related group of industries within an economic sector. Companies in the same economic sector may be similarly affected by economic or market events, making the Fund more vulnerable to unfavorable developments in that economic sector than funds that invest more broadly.

Foreign Securities Risk – Foreign securities are subject to special risks as compared to securities of U.S. issuers. For example, foreign markets can be extremely volatile. Fluctuations in currency exchange rates may impact the value of foreign securities denominated in foreign currencies, or in U.S. dollars, without a change in the intrinsic value of those securities. Foreign securities may be less liquid than domestic securities so that the Fund may, at times, be unable to sell foreign securities at desirable times or prices. Brokerage commissions, custodial fees 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. Foreign governments may impose potentially confiscatory withholding or other taxes, which could reduce the amount of income and capital gains available to distribute to shareholders. There is generally less publicly available information about foreign companies. Investments in foreign companies may be adversely affected by the impact of political, social or diplomatic events, possible imposition of currency exchange controls or possible seizure, expropriation or nationalization of a company or its assets resulting in a partial or total loss of an investment in such foreign companies. Accounting, auditing and financial reporting standards may also be less comprehensive and stringent than those applicable to domestic companies.
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 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, like Russia and those 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 social, political and economic development. Their economies are usually less mature and their securities markets are typically less developed with more limited trading activity than more developed countries. Emerging market securities tend to be more volatile than securities in more developed markets. Many emerging market countries are heavily dependent on international trade, which makes them more sensitive to world commodity prices and economic downturns in other countries.
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. Ownership of Russian securities poses particular risks because ownership records are typically maintained in a decentralized fashion by registrars who may not be subject to effective governmental supervision leading to the possibility that the Fund may lose its ownership rights. In such a case, it may be difficult for the Fund to enforce any rights it may have against the registrar or issuer of the securities.
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 Russia.

Currency Risk – Securities denominated in non-U.S. dollar currencies are subject to the risk that, for example, if the value of a foreign currency were to decline against the U.S. dollar, such decline would reduce the U.S. dollar value of any securities held by the Fund denominated in that currency.

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 present special 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. Investing in special situations may have a magnified effect on the performance of funds with small amounts of assets.

Because the Fund commenced investment operations on August 19, 2011, no year-by-year total return bar chart or average annual total return table is being presented. The year-by year-total return bar chart and the average annual total return table will be provided after the Fund has annual returns for at least one calendar year.

Recent performance information can be obtained by calling toll-free 800.345.6611 or visiting www.columbiamanagement.com.

Investment Objective

Fees and Expenses of the Fund

Shareholder Fees (fees paid directly from your investment)

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Example

Expense Example (Columbia Acorn® Fund) (USD $)	1 Year	3 Years	5 Years	10 Years
Class R4 Shares	86	268	466	1,037
Class R5 Shares	78	243	422	942
Class Y Shares	73	227	395	883

Portfolio Turnover

Principal Investment Strategies

Principal Risks

Performance Information

The bar chart below shows you how the performance of the Fund's Class Z shares has varied from year to year.

Average Annual Total Return as of December 31, 2011

Average Annual Total Returns (Columbia Acorn® Fund)	1 Year	5 Years	10 Years
Class Z Shares	(4.61%)	2.12%	8.24%
Class Z Shares returns after taxes on distributions	(5.23%)	1.58%	7.66%
Class Z Shares returns after taxes on distributions and sale of Fund shares	(2.13%)	1.81%	7.25%
Russell 2500 Index (reflects no deductions for fees, expenses or taxes)	(2.51%)	1.24%	6.57%
S&P 500® Index (reflects no deductions for fees, expenses or taxes)	2.11%	(0.25%)	2.92%
Russell 2000 Index (reflects no deductions for fees, expenses or taxes)	(4.18%)	0.15%	5.62%

The Fund seeks long-term capital appreciation.

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees (Columbia Acorn International®)	Class R4 Shares	Class Y Shares
Maximum sales charge (load) imposed on purchases, as a % of offering price	none	none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or net asset value	none	none

Annual Fund Operating Expenses (Columbia Acorn International®)		Class R4 Shares	Class Y Shares
Management fees		0.76%	0.76%
Distribution and/or service (Rule 12b-1) fees		none	none
Other expenses	^[1]	0.23%	0.10%
Total annual Fund operating expenses		0.99%	0.86%

[1]	Other expenses are based on estimated amounts for the current fiscal year.

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 Class R4 or Class Y shares of the Fund 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 table above.

Based on the assumptions listed above, your costs would be:

Remember this is an example only. Your actual costs may be higher or lower.

The Fund pays 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 32% of the average value of its portfolio.

Under normal circumstances, the Fund invests at least 75% 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).

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 under $5 billion at the time of investment. However, if the Fund's investments in such companies represent less than a majority of its net assets, the Fund may continue to hold and to make additional investments in an existing company in its portfolio even if that company's capitalization has grown to exceed $5 billion. Except as noted above, under normal circumstances, the Fund may invest in other companies with market capitalizations above $5 billion, provided that immediately after that investment a majority of its net assets would be invested in companies with market capitalizations under $5 billion.

Columbia Wanger Asset Management, LLC, the Fund's investment adviser (the Investment Manager), believes that stocks of companies with market capitalizations under $5 billion, which generally are not as well known by financial analysts as larger companies, may offer higher return potential than stocks of larger companies.

The Investment Manager typically seeks companies with:

A strong business franchise that offers growth potential.
Products and services that give the company 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.

Investment Strategy Risk – The Fund's manager uses the principal investment strategies and other investment strategies to seek to achieve the Fund's investment objective. There is no assurance that the Fund will achieve its investment objective. Investment decisions may not produce the expected returns, may cause the Fund's shares to lose value or may cause the Fund to underperform other funds with similar investment objectives.

Market Risk – Market risk refers to the possibility that the market values of securities that the Fund holds will fall, sometimes rapidly or unpredictably, or fail to rise. Security values may fall because of factors affecting individual companies, industries or sectors, or the markets as a whole, reducing the value of an investment in the Fund. Accordingly, an investment in the Fund could lose money over short or even long periods, or fail to increase in value. The market values of the securities the Fund holds also can be affected by changes or perceived changes in U.S. or foreign economies and financial markets, and the liquidity of these securities, among other factors. In general, equity securities tend to have greater price volatility than debt securities.

Smaller Company Securities Risk – Securities of small- or mid-capitalization companies ("smaller companies") can, in certain circumstances, have a higher potential for gains than securities of large-capitalization companies but may also have more risk. For example, smaller companies may be more vulnerable to market downturns and adverse business or economic events than larger, more established companies because they may have more limited financial resources and business operations. These companies are also more likely than large-capitalization companies ("larger companies") to have more limited product lines and operating histories and to depend on smaller management teams. Their securities may trade less frequently and in smaller volumes and may be less liquid and fluctuate more sharply in value than securities of larger companies. In cases where the Fund takes significant positions in smaller companies with limited trading volumes, the liquidation of those positions, particularly in a distressed market, could be prolonged and result in investment losses. In addition, some smaller 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 in a broadly related group of industries within an economic sector. Companies in the same economic sector may be similarly affected by economic or market events, making the Fund more vulnerable to unfavorable developments in that economic sector than funds that invest more broadly.

Foreign Securities Risk – Foreign securities are subject to special risks as compared to securities of U.S. issuers. For example, foreign markets can be extremely volatile. Fluctuations in currency exchange rates may impact the value of foreign securities denominated in foreign currencies, or in U.S. dollars, without a change in the intrinsic value of those securities. Foreign securities may be less liquid than domestic securities so that the Fund may, at times, be unable to sell foreign securities at desirable times or prices. Brokerage commissions, custodial fees 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. Foreign governments may impose potentially confiscatory withholding or other taxes, which could reduce the amount of income and capital gains available to distribute to shareholders. There is generally less publicly available information about foreign companies. Investments in foreign companies may be adversely affected by the impact of political, social or diplomatic events, possible imposition of currency exchange controls or possible seizure, expropriation or nationalization of a company or its assets resulting in a partial or total loss of an investment in such foreign companies. Accounting, auditing and financial reporting standards may also be less comprehensive and stringent than those applicable to domestic companies.
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 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, like Russia and those 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 social, political and economic development. Their economies are usually less mature and their securities markets are typically less developed with more limited trading activity than more developed countries. Emerging market securities tend to be more volatile than securities in more developed markets. Many emerging market countries are heavily dependent on international trade, which makes them more sensitive to world commodity prices and economic downturns in other countries.
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. Ownership of Russian securities poses particular risks because ownership records are typically maintained in a decentralized fashion by registrars who may not be subject to effective governmental supervision leading to the possibility that the Fund may lose its ownership rights. In such a case, it may be difficult for the Fund to enforce any rights it may have against the registrar or issuer of the securities.
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 Russia.

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. Class R4 and Class Y shares of the Fund had not commenced operations prior to the date of this prospectus; therefore, performance information for these classes is not yet available. The performance of the Fund's Class Z shares, which have been outstanding longer than any other share class of the Fund, is shown in the bar chart and average annual total return table. Except for differences in annual returns resulting from differences in expenses, Class R4 and Class Y shares would have annual returns substantially similar to those of Class Z shares, which are not offered in this prospectus, because all classes of the Fund's shares invest in the same portfolio of securities.

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 www.columbiamanagement.com.

Year by Year Total Return (%) as of December 31 Each Year

^[2]


Best and Worst Quarterly Returns During this Period

Best:    2nd quarter 2009:    33.30%

Worst:   3rd quarter 2008:   -23.68%

The table compares the Fund's returns, for each period, with those of the Standard & Poor's (S&P) Global Ex-U.S. Between $500 Million and $5 Billion® Index, the Fund's primary benchmark, the S&P Global Ex-U.S. SmallCap® Index and the MSCI Europe, Australasia and Far East (EAFE) Index (Net). The S&P Global Ex-U.S. Between $500 Million and $5 Billion® Index is a subset of the broad market selected by the index sponsor that represents the mid- and small-cap developed and emerging markets, excluding the United States. The S&P Global Ex-U.S. SmallCap® Index is an unmanaged index consisting of the bottom 20% of institutionally investable capital of developed and emerging countries, excluding the United States. The performance of the S&P Global Ex-U.S. Small Cap® Index is provided to show how the Fund's performance compares to foreign market performance with a similar geographic distribution and wider market cap range than the Fund's primary benchmark. The MSCI EAFE Index (Net) is a capitalization-weighted index that tracks the total return of common stocks in 22 developed-market countries within Europe, Australasia and the Far East. The performance of the MSCI EAFE Index (Net) is provided to show how the Fund's performance compares to a widely recognized broad based index of foreign market performance.

The after-tax returns shown in the table above are calculated using the highest historical individual U.S. federal marginal income tax rates 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-deferred accounts such as 401(k) plans or individual retirement accounts (IRAs).

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.

Investment Objective

Fees and Expenses of the Fund

Shareholder Fees (fees paid directly from your investment)

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Example

Expense Example (Columbia Acorn International Select℠) (USD $)	1 Year	3 Years	5 Years	10 Years
Class R4 Shares	123	384	665	1,466
Class R5 Shares	115	359	622	1,375
Class Y Shares	110	343	595	1,317

Portfolio Turnover

Principal Investment Strategies

Principal Risks

Performance Information

The bar chart below shows you how the performance of the Fund's Class Z shares has varied from year to year.

Average Annual Total Return as of December 31, 2011

Average Annual Total Returns (Columbia Acorn International Select℠)	1 Year	5 Years	10 Years
Class Z Shares	(9.76%)	0.41%	9.22%
Class Z Shares returns after taxes on distributions	(10.24%)	0.01%	9.02%
Class Z Shares returns after taxes on distributions and sale of Fund shares	(5.37%)	0.45%	8.31%
S&P Developed Ex-U.S. Between $2 Billion and $10 Billion® Index (reflects no deductions for fees, expenses or taxes)	(14.01%)	(3.06%)	8.41%
MSCI EAFE Index (Net) (reflects reinvested dividends net of withholding taxes but reflects no deductions for fees, expenses or other taxes)	(12.14%)	(4.72%)	4.67%

The Fund seeks long-term capital appreciation.

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees (Columbia Acorn Select℠)	Class R4 Shares	Class R5 Shares	Class Y Shares
Maximum sales charge (load) imposed on purchases, as a % of offering price	none	none	none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or net asset value	none	none	none

Annual Fund Operating Expenses (Columbia Acorn Select℠)		Class R4 Shares	Class R5 Shares	Class Y Shares
Management fees		0.82%	0.82%	0.82%
Distribution and/or service (Rule 12b-1) fees		none	none	none
Other expenses	^[1]	0.22%	0.14%	0.09%
Total annual Fund operating expenses		1.04%	0.96%	0.91%

[1]	Other expenses are based on estimated amounts for the current fiscal year.

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 Class R4, Class R5 or Class Y shares of the Fund 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 table above.

Based on the assumptions listed above, your costs would be:

Remember this is an example only. Your actual costs may be higher or lower.

The Fund pays 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.

Under normal circumstances, the Fund invests a majority of its net assets in the common stock of companies with market capitalizations under $20 billion at the time of investment. However, if the Fund's investments in such companies represent less than a majority of its net assets, the Fund may continue to hold and to make additional investments in an existing company in its portfolio even if that company's capitalization has grown to exceed $20 billion. Except as noted above, under normal circumstances, the Fund may invest in other companies with market capitalizations above $20 billion, provided that immediately after that investment a majority of its net assets would be invested in companies with market capitalizations under $20 billion.

Columbia Wanger Asset Management, LLC, the Fund's investment adviser (the Investment Manager), believes that stocks of companies with market capitalizations under $20 billion, 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 Colombia).

The Fund takes advantage of the Investment Manager's research and stock-picking capabilities to invest in a limited number of companies (generally between 30-60), 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 that give the company a competitive advantage.
A stock price the Investment Manager believes is reasonable relative to the assets and earning power of the company.

The Fund may also invest in companies that the Investment Manager believes have good operational fundamentals but that the Investment Manager believes are undervalued due to negative investor sentiment related to company-specific or market-related conditions. Investments in turnaround and development stage companies may also be made when the Investment Manager believes potential returns outweigh risks of losses.

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.

Investment Strategy Risk – The Fund's manager uses the principal investment strategies and other investment strategies to seek to achieve the Fund's investment objective. There is no assurance that the Fund will achieve its investment objective. Investment decisions may not produce the expected returns, may cause the Fund's shares to lose value or may cause the Fund to underperform other funds with similar investment objectives.

Market Risk – Market risk refers to the possibility that the market values of securities that the Fund holds will fall, sometimes rapidly or unpredictably, or fail to rise. Security values may fall because of factors affecting individual companies, industries or sectors, or the markets as a whole, reducing the value of an investment in the Fund. Accordingly, an investment in the Fund could lose money over short or even long periods, or fail to increase in value. The market values of the securities the Fund holds also can be affected by changes or perceived changes in U.S. or foreign economies and financial markets, and the liquidity of these securities, among other factors. In general, equity securities tend to have greater price volatility than debt securities.

Smaller Company Securities Risk – Securities of small- or mid-capitalization companies ("smaller companies") can, in certain circumstances, have a higher potential for gains than securities of large-capitalization companies but may also have more risk. For example, smaller companies may be more vulnerable to market downturns and adverse business or economic events than larger, more established companies because they may have more limited financial resources and business operations. These companies are also more likely than large-capitalization companies ("larger companies") to have more limited product lines and operating histories and to depend on smaller management teams. Their securities may trade less frequently and in smaller volumes and may be less liquid and fluctuate more sharply in value than securities of larger companies. In cases where the Fund takes significant positions in smaller companies with limited trading volumes, the liquidation of those positions, particularly in a distressed market, could be prolonged and result in investment losses. In addition, some smaller 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 in a broadly related group of industries within an economic sector. Companies in the same economic sector may be similarly affected by economic or market events, making the Fund more vulnerable to unfavorable developments in that economic sector than funds that invest more broadly.

Foreign Securities Risk – Foreign securities are subject to special risks as compared to securities of U.S. issuers. For example, foreign markets can be extremely volatile. Fluctuations in currency exchange rates may impact the value of foreign securities denominated in foreign currencies, or in U.S. dollars, without a change in the intrinsic value of those securities. Foreign securities may be less liquid than domestic securities so that the Fund may, at times, be unable to sell foreign securities at desirable times or prices. Brokerage commissions, custodial fees 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. Foreign governments may impose potentially confiscatory withholding or other taxes, which could reduce the amount of income and capital gains available to distribute to shareholders. There is generally less publicly available information about foreign companies. Investments in foreign companies may be adversely affected by the impact of political, social or diplomatic events, possible imposition of currency exchange controls or possible seizure, expropriation or nationalization of a company or its assets resulting in a partial or total loss of an investment in such foreign companies. Accounting, auditing and financial reporting standards may also be less comprehensive and stringent than those applicable to domestic companies.
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 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, like Russia and those 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 social, political and economic development. Their economies are usually less mature and their securities markets are typically less developed with more limited trading activity than more developed countries. Emerging market securities tend to be more volatile than securities in more developed markets. Many emerging market countries are heavily dependent on international trade, which makes them more sensitive to world commodity prices and economic downturns in other countries.
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. Ownership of Russian securities poses particular risks because ownership records are typically maintained in a decentralized fashion by registrars who may not be subject to effective governmental supervision leading to the possibility that the Fund may lose its ownership rights. In such a case, it may be difficult for the Fund to enforce any rights it may have against the registrar or issuer of the securities.
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 Russia.

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.

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. Class R4, Class R5 and Class Y shares of the Fund had not commenced operations prior to the date of this prospectus; therefore, performance information for these classes is not yet available. The performance of the Fund's Class Z shares, which have been outstanding longer than any other share class of the Fund, is shown in the bar chart and average annual total return table. Except for differences in annual returns resulting from differences in expenses, Class R4, Class R5 and Class Y shares would have annual returns substantially similar to those of Class Z shares, which are not offered in this prospectus, because all classes of the Fund's shares invest in the same portfolio of securities.

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 www.columbiamanagement.com.

Year by Year Total Return (%) as of December 31 Each Year

^[4]


Best and Worst Quarterly Returns During this Period

Best:    2nd quarter 2009:    28.11%

Worst:   4th quarter 2008:   -30.14%

The table compares the Fund's returns for each period with those of the Standard & Poor's (S&P) MidCap 400® Index, the Fund's primary benchmark, and the S&P 500® Index. The S&P MidCap 400® Index is a market value-weighted index that tracks the performance of 400 mid-cap U.S. companies. The S&P 500® Index tracks the performance of 500 widely held, large-capitalization U.S. stocks. Although the Fund typically invests in companies with market capitalizations under $20 billion at the time of investment, the comparison to the S&P 500® Index is presented to show performance against a widely recognized market index.

The after-tax returns shown in the table above are calculated using the highest historical individual U.S. federal marginal income tax rates 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-deferred accounts such as 401(k) plans or individual retirement accounts (IRAs).

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.

Investment Objective

Fees and Expenses of the Fund

Shareholder Fees (fees paid directly from your investment)

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

Example

Expense Example (Columbia Acorn USA®) (USD $)	1 Year	3 Years	5 Years	10 Years
Class R4 Shares	110	343	595	1,317
Class R5 Shares	102	318	552	1,225
Class Y Shares	97	303	526	1,166

Portfolio Turnover

Principal Investment Strategies

Principal Risks

Performance Information

The bar chart below shows you how the performance of the Fund's Class Z shares has varied from year to year.

Average Annual Total Return as of December 31, 2011

Average Annual Total Returns (Columbia Acorn USA®)	1 Year	5 Years	10 Years
Class Z Shares	(4.95%)	0.82%	6.30%
Class Z Shares returns after taxes on distributions	(5.04%)	0.52%	6.02%
Class Z Shares returns after taxes on distributions and sale of Fund shares	(3.10%)	0.69%	5.54%
Russell 2000 Index (reflects no deductions for fees, expenses or taxes)	(4.18%)	0.15%	5.62%

The Fund seeks long-term capital appreciation.

This table describes the fees and expenses that you may pay if you buy and hold shares of the Fund.

Shareholder Fees (Columbia Thermostat Fund℠)	Class R4 Shares	Class R5 Shares	Class Y Shares
Maximum sales charge (load) imposed on purchases, as a % of offering price	none	none	none
Maximum deferred sales charge (load) imposed on redemptions, as a % of the lower of the original purchase price or net asset value	none	none	none

Annual Fund Operating Expenses (Columbia Thermostat Fund℠)		Class R4 Shares	Class R5 Shares	Class Y Shares
Management fees		0.10%	0.10%	0.10%
Distribution and/or service (Rule 12b-1) fees		none	none	none
Other expenses	^[1]	0.32%	0.24%	0.19%
Acquired Fund Fees and Expenses		0.65%	0.65%	0.65%
Total annual Fund operating expenses	^[2]	1.07%	0.99%	0.94%
Fee waivers and/or reimbursements		(0.17%)	(0.07%)	(0.07%)
Total annual Fund operating expenses after fee waivers and/or reimbursements		0.90%	0.92%	0.87%

[1]

Other expenses are based on estimated amounts for the current fiscal year.

[2]

Columbia Wanger Asset Management, LLC (the Investment Manager) has contractually agreed to waive fees and reimburse certain expenses of the Fund so that ordinary operating expenses (excluding distribution and service fees, interest and fees on borrowings and expenses associated with the Fund's investment in other investment companies) do not exceed the annual rates of 0.25% of the Fund's average daily net assets for Class R4, 0.27% for Class R5 and 0.22% for Class Y, through November 8, 2013. The figure shown here is the amount of expected waivers and/or reimbursements. This fee and expense arrangement may only be modified or amended with approval from all parties to such arrangement, including the Fund and the Investment Manager.

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 Class R4, Class R5 or Class Y shares of the Fund 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 table above.

Since the waivers and/or reimbursements shown in the Annual Fund Operating Expenses table above expire on November 8, 2013, they are only reflected in the 1 year example and the first year of the 3, 5 and 10 year examples.

Based on the assumptions listed above, your costs would be:

Remember this is an example only. Your actual costs may be higher or lower.

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 130% of the average value of its portfolio.

The Fund pursues its investment objective by investing in other mutual funds. As a "fund of funds," under normal circumstances, the Fund allocates at least 95% of its net assets (stock/bond assets) among a selected group of stock and bond mutual funds (Portfolio Funds) according to the current level of Standard & Poor's (S&P) 500® Index. Generally, when the S&P 500® Index goes up in relation to predetermined ranges set by Columbia Wanger Asset Management, LLC, the Fund's investment adviser (the Investment Manager), the Fund sells a portion of its stock funds and invests more in the bond funds and when the S&P 500® Index goes down in relation to the ranges, the Fund increases its investment in the stock 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.

Many asset allocation funds typically move assets from stocks to bonds when the market goes up, and from bonds to stocks when the market goes down. Most asset allocation funds are run by sophisticated investment professionals, who make subjective decisions based on economic and financial data and complex graphs of market behavior. By contrast, the day-to-day investment decisions for the Fund are made according to a single predetermined rule. 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.

Because the Fund invests according to a pre-set program, there is no need for subjective day-to-day management. Although another successful asset allocation strategy might do better than the Fund, the Fund is designed for those who doubt the wisdom of trying to "time" the market and are unsure of the long-term trend of the stock market. The Fund takes psychology out of investing; it avoids the temptation to buy more stocks because the stock market is currently going up or to sell stocks because the market is declining. The Fund operates continuously and substantially automatically, subject to periodic review of the pre-set program by the Investment Manager and the Fund's Board of Trustees. As described more fully below, the Investment Manager has the authority to review the structure and allocation ranges of the stock/bond allocation table and to make any changes considered appropriate.

The Investment Manager chooses the Portfolio Funds to provide participation in the major sectors of the stock and bond markets. If you believe that the stock market will tend to go up most of the time, then you should probably own a fully invested stock fund and use a buy-and-hold strategy. Buy-and-hold was an excellent strategy in the 1982-1999 bull market. However, there have been long periods in the past when buy-and-hold was not the best strategy, such as 1930-1954 and 1969-1981, when the market fluctuated but did not make significant new highs. The Fund may be a good investment choice for you if you believe that the market may fluctuate in a trading range for many years, that a remarkable bull market ended early in 2000 and that the market may not reach significant new highs for many years.

The Fund invests its stock/bond assets among the Portfolio Funds according to an asset allocation table. The current allocation table is set forth below.

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 1750		10	%		90	%
over 1700-1750		15	%		85	%
over 1650-1700		20	%		80	%
over 1600-1650		25	%		75	%
over 1550-1600		30	%		70	%
over 1500-1550		35	%		65	%
over 1450-1500		40	%		60	%
over 1400-1450		45	%		55	%
over 1350-1400		50	%		50	%
over 1300-1350		55	%		45	%
over 1250-1300		60	%		40	%
over 1200-1250		65	%		35	%
over 1150-1200		70	%		30	%
over 1100-1150		75	%		25	%
over 1050-1100		80	%		20	%
over 1000-1050		85	%		15	%
1000 and under		90	%		10	%

When the S&P 500® Index moves into a new band on the table, the Fund promptly 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. The only exception will be a "31-day Rule"; in order to reduce taxable events, 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 1150-1200 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). 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 an illustrative example, suppose the following:

Date	Level of the S&P 500® Index	How the Fund will invest the Stock/ Bond Assets
Nov. 1	We begin when the market is 1380	50% stocks, 50% bonds
Dec. 1	The S&P 500® goes to 1401	rebalance 45% stocks, 55% bonds
Dec. 6	The S&P 500® drops back to 1390	no reversal for 31 days
Jan. 2	The S&P 500® is at 1352	rebalance 50% stocks, 50% bonds
Jan. 20	The S&P 500® drops to 1349	rebalance 55% stocks, 45% bonds
	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.
Jan. 30	The S&P 500® goes up to 1355	no reversal for 31 days
Feb. 20	The S&P 500® is at 1360	rebalance 50% stocks, 50% bonds

The following table shows the seven stock Portfolio Funds and three bond Portfolio Funds that the Fund currently uses in its "fund of funds" structure and the current allocation percentage for each Portfolio Fund within the stock or bond category. 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 allocation percentage within each stock/bond category is achieved by rebalancing the investments within the category 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 does 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 stock/bond allocation table to the Portfolio Funds or to the relative allocation among them). Until a subsequent rebalancing, the Fund's investments in, and redemptions from, the stock Portfolio Funds or the bond Portfolio Funds are allocated among the Portfolio Funds in a manner that will reduce any deviation of the relative values of the Fund's holdings of the Funds from the allocation percentages shown below.

Allocation of Stock/Bond Assets Within Asset Classes

Stock Funds	Type of Fund	Allocation
Columbia Acorn Fund	Small/Mid-cap growth	15	%
Columbia Acorn Select	Mid-cap growth	10	%
Columbia Acorn International	Small/Mid-cap international growth	20	%
Columbia Dividend Income Fund	Large-cap value	20	%
Columbia Large Cap Enhanced Core Fund	Large-cap blend	10	%
Columbia Contrarian Core Fund	Large-cap blend	15	%
Columbia Select Large Cap Growth Fund	Large-cap growth	10	%
Total		100	%

Bond Funds	Type of Fund	Allocation
Columbia Intermediate Bond Fund	Intermediate-term bonds	50	%
Columbia Income Opportunities Fund	High-yield bonds	30	%
Columbia U.S. Treasury Index Fund	U.S. Treasury notes/bonds	20	%

Total		100	%

The Investment Manager has the authority to review the Portfolio Funds and the relative stock/bond allocation percentages among them and to make any changes considered appropriate.

Each of the Portfolio Funds is currently 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. On an annual basis, or on an "emergency" basis if necessary, the Investment Manager reviews the structure, allocation percentages and Portfolio Funds and makes any changes considered appropriate. The Investment Manager typically addresses the following questions:

Should the stock/bond allocation table be revised (perhaps because the stock market has made a long-term move outside of the bands set forth above)?
Should there be a change in the Portfolio Funds or should there be a change in the percentage allocations among the stock/bond funds (perhaps because of a change of portfolio managers, change of investment style, change in relative valuation or a reorganization of a Portfolio Fund)?

Any such changes by the Investment Manager are expected to be infrequent.

Investment Strategy Risk – The Fund's manager uses the principal investment strategies and other investment strategies to seek to achieve the Fund's investment objective. There is no assurance that the Fund will achieve its investment objective. Investment decisions may not produce the expected returns, may cause the Fund's shares to lose value or may cause the Fund to underperform other funds with similar investment objectives.

Allocation Risk – The Fund 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, or that the investments themselves will not produce the returns expected.

Investing in Other Funds Risk – The performance of the underlying fund(s) in which the Fund invests could be adversely affected if other entities that invest in the same underlying fund(s) make relatively large investments or redemptions in the underlying fund(s). In addition, because the expenses and costs of the underlying fund(s) are shared by investors in the underlying fund, redemptions by other investors in the underlying fund could result in decreased economies of scale and increased operating expenses for the underlying fund. The Fund, and its shareholders, indirectly bear a portion of the expenses of the underlying fund(s). These transactions might also result in higher brokerage, tax or other costs for the Fund. This risk may be particularly important when one investor owns a substantial portion of any underlying fund. In addition, the Investment Manager has the authority to change the underlying fund(s) in which the Fund invests or to change the percentage of the Fund's investments allocated to each underlying fund. If an underlying fund pays fees to the Investment Manager or its affiliates, such as advisory fees, this could result in the Investment Manager having a potential conflict of interest in selecting the underlying fund(s) in which the Fund invests or in determining the percentage of the Fund's investments allocated to each underlying fund. In addition, the underlying funds are themselves subject to Investment Strategy Risk.

The Fund is subject indirectly to the following risks of the Portfolio Funds:

Market Risk – Market risk refers to the possibility that the market values of securities that a Portfolio Fund holds will fall, sometimes rapidly or unpredictably, or fail to rise. Security values may fall because of factors affecting individual companies, industries or sectors, or the markets as a whole, reducing the value of an investment in the Portfolio Fund. Accordingly, an investment in a Portfolio Fund could lose money over short or even long periods, or fail to increase in value. The market values of the securities the Portfolio Fund holds also can be affected by changes or perceived changes in U.S. or foreign economies and financial markets, and the liquidity of these securities, among other factors. In general, equity securities tend to have greater price volatility than debt securities.

Interest Rate Risk – Debt securities are subject to interest rate risk. In general, if prevailing interest rates rise, the values of debt securities will tend to fall, and if interest rates fall, the values of debt securities will tend to rise. Changes in the value of a debt security usually will not affect the amount of income a Portfolio Fund receives from it but may affect the value of the Portfolio Fund's shares. Interest rate risk is generally greater for debt securities with longer maturities/durations.

Credit Risk – Credit risk applies to most debt securities, but is generally less of a factor for obligations backed by the "full faith and credit" of the U.S. Government. A Portfolio Fund could lose money if the issuer of a debt security owned by the Fund is unable or perceived to be unable to pay interest or repay principal when it becomes due. Various factors could affect the issuer's actual or perceived willingness or ability to make timely interest or principal payments, including changes in the issuer's financial condition or in general economic conditions. Debt securities 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 securities 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.

Low and Below Investment Grade Securities Risk – Debt securities with the lowest investment grade rating (e.g., BBB by Standard & Poor's, a division of the McGraw-Hill Companies, Inc. (S&P), or Fitch, Inc. (Fitch) or Baa by Moody's Investors Service, Inc. (Moody's)), or that are below investment grade (which are commonly referred to as "junk bonds") (e.g., BB or below by S&P or Fitch or Ba by Moody's) and unrated securities of comparable quality are more speculative than securities with higher ratings and may experience greater price fluctuations. These securities tend to be more sensitive to credit risk than higher-rated securities, particularly during a downturn in the economy, which is more likely to weaken the ability of the issuers to make principal and interest payments on these securities. These securities typically pay a premium – a higher interest rate or yield – because of the increased risk of loss, including default. These securities also are generally less liquid than higher-rated securities. The securities ratings provided by Moody's, S&P and Fitch are based on analyses by these ratings agencies of the credit quality of the securities and may not take into account every risk related to whether interest or principal will be timely repaid.

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 Investment Manager's future value assessment of that security, or may decline. There is also a risk that it may take longer than expected for the value of these investments to rise to the believed 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 – Because growth securities typically trade at a higher multiple of earnings than other types of securities, the market values of growth securities may be more sensitive to changes in current or expected earnings than the market values of other types of securities. 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 in a broadly related group of industries within an economic sector. Companies in the same economic sector may be similarly affected by economic or market events, making the Fund more vulnerable to unfavorable developments in that economic sector than funds that invest more broadly.

Foreign Securities Risk – Foreign securities are subject to special risks as compared to securities of U.S. issuers. For example, foreign markets can be extremely volatile. Fluctuations in currency exchange rates may impact the value of foreign securities denominated in foreign currencies, or in U.S. dollars, without a change in the intrinsic value of those securities. Foreign securities may be less liquid than domestic securities so that the Portfolio Fund may, at times, be unable to sell foreign securities at desirable times or prices. Brokerage commissions, custodial fees and other fees are also generally higher for foreign securities. The Portfolio 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. Foreign governments may impose potentially confiscatory withholding or other taxes, which could reduce the amount of income and capital gains available to distribute to shareholders. There is generally less publicly available information about foreign companies. Investments in foreign companies may be adversely affected by the impact of political, social or diplomatic events, possible imposition of currency exchange controls or possible seizure, expropriation or nationalization of a company or its assets resulting in a partial or total loss of an investment in such foreign companies. Accounting, auditing and financial reporting standards may also be less comprehensive and stringent than those applicable to domestic companies.
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 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, like Russia and those 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 social, political and economic development. Their economies are usually less mature and their securities markets are typically less developed with more limited trading activity than more developed countries. Emerging market securities tend to be more volatile than securities in more developed markets. Many emerging market countries are heavily dependent on international trade, which makes them more sensitive to world commodity prices and economic downturns in other countries.
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. Ownership of Russian securities poses particular risks because ownership records are typically maintained in a decentralized fashion by registrars who may not be subject to effective governmental supervision leading to the possibility that the Fund may lose its ownership rights. In such a case, it may be difficult for the Fund to enforce any rights it may have against the registrar or issuer of the securities.
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 Russia.

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

Index Risk – U.S. Treasury Index Fund's value will generally decline when the performance of its targeted index declines. Because U.S. Treasury Index Fund is designed to track an index before fees and expenses, U.S. Treasury Index Fund cannot purchase other securities that may help offset declines in its index. In addition, because U.S. Treasury Index Fund may not hold all issues included in its index, may not always be fully invested, and bears advisory, administrative and other expenses and transaction costs in trading securities, U.S. Treasury Index Fund's performance may fail to match the performance of its targeted index, after taking expenses into account. It is not possible to invest directly in an index.

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. Securities guaranteed by the Federal Deposit Insurance Corporation under its Temporary Liquidity Guarantee Program (TLGP) are subject to certain risks, including whether such securities will continue to trade in line with recent experience in relation to treasury and government agency securities in terms of yield spread and the volatility of such spread, as well as uncertainty as to how such securities will trade in the secondary market and whether that market will be liquid or illiquid. The TLGP is subject to change.

Derivatives Risk – 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 LIBOR) or market indices (such as the S&P 500® Index). Derivatives involve special risks and may result in losses or may limit a Portfolio Fund's potential gain from favorable market movements. Derivative strategies often involve leverage, which may exaggerate a loss, potentially causing a Portfolio Fund to lose more money than it would have lost had it invested in the underlying security or other asset. The values of derivatives may move in unexpected ways, especially in unusual market conditions, and may result in increased volatility, 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 a Portfolio Fund's potential inability to terminate or to sell derivative positions. A liquid secondary market may not always exist for the Portfolio Fund's derivative positions at times when the Portfolio 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. A Portfolio 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 recently been enacted that provides for new clearing, margin, reporting and registration requirements for participants in the derivatives market. While the ultimate impact is not yet clear, these changes could restrict and/or impose significant costs or other burdens upon the Fund's participation in derivatives transactions. For more information on the risks of derivative investments and strategies, see the Statement of Additional Information.

Convertible Securities Risk – Certain Portfolio Funds invest in convertible securities, which are subject to the usual risks associated with debt securities, such as interest rate risk and credit risk. Convertible securities also react to changes in the value of the common stock into which they convert. 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 security, 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 Portfolio Fund may be forced to convert a convertible security before it otherwise would choose to do so, which may decrease the Portfolio Fund's return.

Non-Diversified Mutual Fund Risk – If a Portfolio Fund is non-diversified, that Portfolio Fund generally may invest a greater percentage of its total assets in the securities of fewer issuers than may a "diversified" fund. This increases the risk that a change in the value of any one investment held by the non-diversified Portfolio Fund could affect the overall value of the Portfolio Fund more than it would affect that of a diversified fund holding a greater number of investments. Accordingly, a non-diversified Portfolio Fund's value will likely be more volatile than the value of more diversified funds. A Portfolio Fund that is non-diversified may not operate as a non-diversified fund at all times.

Technology Sector Risk – Companies in the technology sector are subject to significant competitive pressures, such as aggressive pricing of their products or services, new market entrants, competition for market share, short product cycles due to an accelerated rate of technological developments and the potential for limited earnings and/or falling profit margins. These companies also face the risks that new services, equipment or technologies will not be accepted by consumers and businesses or will become rapidly obsolete. These factors can affect the profitability of technology companies and, as a result, the value of their securities. Also, patent protection is integral to the success of many companies in the technology sector, and profitability can be affected materially by, among other things, the cost of obtaining (or failing to obtain) patent approvals, the cost of litigating patent infringement and the loss of patent protection for products (which significantly increases pricing pressures and can materially reduce profitability with respect to such products). In addition, many technology companies have limited operating histories. Prices of these companies' securities historically have been more volatile than other securities, especially over the short term. Because certain Portfolio Funds invest a significant portion of their net assets in the equity securities of technology companies, a Portfolio Fund's price may be more volatile than a fund that is invested in a more diverse range of market sectors.

Health Care Sector Risk - Companies in the health care sector are subject to extensive government regulation. Their profitability can be affected significantly and adversely by restrictions on government reimbursement for medical expenses, government approval of medical products and services, competitive pricing pressures, an increased emphasis on outpatient and other alternative services and other factors. Patent protection is integral to the success of companies in the health care sector, and profitability can be affected materially by, among other things, the cost of obtaining (or failing to obtain) patent approvals, the cost of litigating patent infringement and the loss of patent protection for medical products (which significantly increases pricing pressures and can materially reduce profitability with respect to such products). Companies in the health care sector also potentially are subject to extensive product liability and other similar litigation. Companies in the health care sector are affected by the rising cost of medical products and services, and the effects of such rising costs can be particularly pronounced for companies that are dependent on a relatively limited number of products or services. Medical products also frequently become obsolete due to industry innovation or other causes. Because certain Portfolio Funds invest a significant portion of their net assets in the equity securities of health care companies, a Portfolio Fund's price may be more volatile than a fund that is invested in a more diverse range of market sectors.

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. Class R4, Class R5 and Class Y shares of the Fund had not commenced operations prior to the date of this prospectus; therefore, performance information for these classes is not yet available. The performance of the Fund's Class Z shares, which have been outstanding longer than any other share class of the Fund, is shown in the bar chart and average annual total return table. Except for differences in annual returns resulting from differences in expenses, Class R4, Class R5 and Class Y shares would have annual returns substantially similar to those of Class Z shares, which are not offered in this prospectus, because all classes of the Fund's shares invest in the same portfolio of securities.

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 www.columbiamanagement.com.

Year by Year Total Return (%) as of December 31 Each Year

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Best and Worst Quarterly Returns During this Period

Best:    2nd quarter 2009:    19.33%

Worst:   4th quarter 2008:   -19.26%

The table compares the Fund's returns for each period with those of the S&P 500® Index, the Fund's primary benchmark for equity securities, the Barclays U.S. Aggregate Bond Index, the Fund's primary benchmark for debt securities, the Lipper Flexible Portfolio Funds Index and a 50/50 Blended Benchmark. The S&P 500® Index tracks the performance of 500 widely held, large-capitalization U.S. stocks. The Barclays 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 Lipper Flexible Portfolio Funds Index is an equal-weighted index of the 30 largest mutual funds within the Flexible Portfolio fund classification, as defined by Lipper, and shows how the Fund's performance compares with the returns of an index of funds with similar investment objectives. The 50/50 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 Barclays 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 50/50 Blended Benchmark.

The after-tax returns shown in the table above are calculated using the highest historical individual U.S. federal marginal income tax rates 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-deferred accounts such as 401(k) plans or individual retirement accounts (IRAs).