N-CSR

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM N-CSR

CERTIFIED SHAREHOLDER REPORT OF REGISTERED
MANAGEMENT INVESTMENT COMPANIES

Investment Company Act file number			811-01829
Columbia Acorn Trust
(Exact name of registrant as specified in charter)
One Financial Center, Boston, Massachusetts					02111
(Address of principal executive offices)					(Zip code)
James R. Bordewick, Jr., Esq. Columbia Management Advisors, LLC One Financial Center Boston, MA 02111
(Name and address of agent for service)
Registrant’s telephone number, including area code:				1-617-426-3750
Date of fiscal year end:	December 31
Date of reporting period:		December 31, 2009

Form N-CSR is to be used by management investment companies to file reports with the Commission not later than 10 days after the transmission to stockholders of any report that is required to be transmitted to stockholders under Rule 30e-1 under the Investment Company Act of 1940 (17 CFR 270.30e-1). The Commission may use the information provided on Form N-CSR in its regulatory, disclosure review, inspection, and policymaking roles.

A registrant is required to disclose the information specified by Form N-CSR, and the Commission will make this information public. A registrant is not required to respond to the collection of information contained in Form N-CSR unless the Form displays a currently valid Office of Management and Budget (“OMB”) control number. Please direct comments concerning the accuracy of the information collection burden estimate and any suggestions for reducing the burden to Secretary, Securities and Exchange Commission, 450 Fifth Street, NW, Washington, DC 20549-0609. The OMB has reviewed this collection of information under the clearance requirements of 44 U.S.C. § 3507.

Item 1. Reports to Stockholders.

Q4 2009

Columbia Management^®

Columbia Acorn Family of Funds

Class Z Shares

Managed by Columbia Wanger Asset Management, L.P.

Annual Report

December 31, 2009

n  Columbia^SM
Acorn® Fund

n  Columbia^SM
Acorn International®

n  Columbia^SM
Acorn USA®

n  Columbia^SM
Acorn International Select^SM

n  Columbia^SM
Acorn Select^SM

n  Columbia^SM
Thermostat Fund^SM

NOT FDIC INSURED

NOT BANK ISSUED

May Lose Value

No Bank Guarantee

Columbia Acorn Family of Funds

Descriptions of Indexes Included in this Report

•  50/50 Blended Benchmark, established by the Fund's advisor, is an equally weighted custom composite of Columbia Thermostat Fund's primary equity and primary debt benchmarks, the S&P 500 Index and the Barclays Capital 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.

•  Barclays Capital 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.

•  Lipper Indexes include the largest funds tracked by Lipper, Inc. in the named category. Lipper Small-Cap Core Funds Index, 30 largest small-cap core funds; Lipper Mid-Cap Growth Funds Index, 30 largest mid-cap growth funds; Lipper International Small/Mid Growth Funds Index, 10 largest non-U.S. small/mid growth funds, i ncluding Columbia Acorn International; Lipper Small-Cap Growth Funds Index, 30 largest small-cap growth funds; Lipper International Funds Index, 30 largest non-U.S. funds, excluding non-U.S. small-cap funds; Lipper Flexible Portfolio Funds Index, an equal-weighted index of the 30 largest mutual funds within the Flexible Portfolio fund classification, as defined by Lipper.

•  Morgan Stanley Capital International Europe, Australasia, Far East (MSCI EAFE) Index is a capitalization-weighted index that tracks the total return of common stocks in 21 developed-market countries within Europe, Australasia and the Far East.

•  Russell 2000 Index measures the performance of the 2,000 smallest companies in the Russell 3000 Index, which represents approximately 8% of the total market capitalization of the Russell 3000 Index.

•  Russell 2500 Index measures the performance of the 2,500 smallest companies in the Russell 3000 Index, which represents approximately 17% of the total market capitalization of the Russell 3000 Index.

•  Standard & Poor's (S&P) 500 Index tracks the performance of 500 widely held, large-capitalization U.S. stocks.

•  Standard & Poor's (S&P) MidCap 400 Index is a market value-weighted index that tracks the performance of 400 mid-cap U.S.companies.

•  S&P Developed Ex-U.S. Between $2 Billion and $10 Billion Index is a subset of the broad market selected by the index sponsor representing the mid-cap developed market, excluding the United States.

•  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.

•  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 representing the mid- and small-cap developed and emerging markets, excluding the United States.

Unlike mutual funds, indexes are not managed and do not incur fees or expenses. It is not possible to invest directly in an index.

The views expressed in the "Squirrel Chatter II" and "In a Nutshell" commentaries reflect the current views of the respective authors. These views are not guarantees of future performance and involve certain risks, uncertainties and assumptions that are difficult to predict so actual outcomes and results may differ significantly from the views expressed. These views are subject to change at any time based upon economic, market or other conditions and the respective authors disclaim any responsibility to update such views. These views may not be relied upon as investment advice and, because investment decisions for a Columbia Acorn Fund are based on numerous factors, may not be relied upon as an indication of trading intent on behalf of any particular Columbia Acorn Fund. References to specific company securities should not be construed as a recommendation or investment advice and there can be no assurance that as of the date of publication of this report, the securities mentioned in each Fund's portfolio are still held or that the securities sold have not been repurchased.

Letter to Shareholders from the
Columbia Acorn Board of Trustees

Change and Continuity

Fellow Shareholders:

Our Funds enter the New Year facing important governance changes. In the next few months, your Trustees expect that the Fund's investment adviser, Columbia Wanger Asset Management ("CWAM"), will be sold to Ameriprise Financial, Inc. By law, your Trustees must determine whether CWAM should continue to serve as the Funds' investment adviser under its new ownership. Accordingly, the Board has spent significant time and effort considering whether this transaction is in the best interests of shareholders. A specially appointed committee of the Board has reviewed and is negotiating a proposed new investment advisory agreement and contracts with other critical service providers required upon a change of control of the investment adviser. The law also requires that shareholders approve the new investment advisory contract, and proxy materials describing these matters will be sent to shareholders before a change of control takes place.

A second area of change – and continuity – relates to your Funds' Trustees. Sadly, former Chair Bob Nason passed away last June and long-time trustee Jerry Kahn retired at year end. After a transitional period following Bob's death, the Board elected Steve Kaplan as Vice Chair and the undersigned as Chair. I am happy to report that the Board has also elevated Ralph Wanger to "Trustee Emeritus" upon his retirement as a Trustee later this year. This emeritus status allows the Board to continue to benefit from Ralph's experience, insight, and wisdom. Finally, we've rotated the leadership of each of the Board's committees. These changes reflect succession plans put in place by Bob Nason and Allan Muchin (the immediate past Vice Chair) in an effort to preserve the Board's strong independent tradition.

All of your Trustees are, like you, shareholders in the Funds. As such, we were heartened by the recent recovery in the financial markets and the Funds. The domestic Funds did particularly well, exceeding their benchmarks by a significant margin. More importantly, all of the Funds continue to do well when considered over the longer term. Such long-term success remains the constant focus of the Board.

Transitions are rarely easy. That said, your Trustees have worked to identify potential problems and minimize the impact should any arise. In taking these actions, we are following the example of the thoughtful and independent Acorn directors who came before us. They taught your Board to understand and appreciate its role as an unwavering advocate for shareholders and the ultimate protector of the Funds.

Thank you for your trust in the Acorn Funds.

James A. Star
Independent Chairman of the Board of Trustees
Columbia Acorn Trust

Columbia Acorn Family of Funds

Table of Contents

Performance At A Glance	1
Squirrel Chatter II: Skill and Luck	2
Understanding Your Expenses	4
Columbia Acorn Fund
In a Nutshell	6
At a Glance	7
Major Portfolio Changes	18
Statement of Investments	20
Columbia Acorn International
In a Nutshell	8
At a Glance	9
Major Portfolio Changes	32
Statement of Investments	34
Portfolio Diversification	42
Columbia Acorn USA
In a Nutshell	10
At a Glance	11
Major Portfolio Changes	43
Statement of Investments	44
Columbia Acorn International Select
In a Nutshell	12
At a Glance	13
Major Portfolio Changes	52
Statement of Investments	53
Portfolio Diversification	56

Columbia Acorn Select
In a Nutshell	14
At a Glance	15
Major Portfolio Changes	57
Statement of Investments	58
Columbia Thermostat Fund
In a Nutshell	16
At a Glance	17
Statement of Investments	63
Columbia Acorn Family of Funds
Statements of Assets and Liabilities	66
Statements of Operations	67
Statements of Changes in Net Assets	68
Financial Highlights	72
Notes to Financial Statements	75
Report of Independent Registered Public Accounting Firm	84
Federal Income Tax Information	85
Board of Trustees and Management of Columbia Acorn Funds	86
Columbia Acorn Family of Funds Information	89

No 2009 Year-end Capital Gain Distributions for the Columbia Acorn Funds

None of the Columbia Acorn Funds paid short-term or long-term capital gain distributions at year-end. As noted below, Columbia Acorn Fund did distribute ordinary income. The record date was December 8, 2009. The ex-dividend date was December 9, 2009, and the payable date was December 10, 2009.

	Ordinary Income		Reinvestment Price
Columbia Acorn Fund	$	0.0493	$	23.58

Bank of America To Sell Columbia Management Group, LLC

On September 29, 2009, Bank of America Corporation entered into an agreement with Ameriprise Financial, Inc. ("Ameriprise") to sell a portion of the long-term asset management business of Columbia Management Group, LLC, including 100% of Columbia Wanger Asset Management, L.P.

The planned acquisition of Columbia Management's long-term asset management business by Ameriprise is subject to federal, state and international regulatory approvals.

Columbia Acorn Family of Funds

Performance At A Glance Class Z Average Annual Total Returns through 12/31/09

	NAV on 12/31/09		4th quarter*			1 year			3 years			5 years			10 years			Life of Fund
Columbia Acorn Fund (ACRNX) (6/10/70)		$24.68		5.74%			39.65%			-2.59%			3.65%			7.93%			14.75%
Russell 2500 Index				5.08	%		34.39	%		-4.86	%		1.58	%		4.91	%		NA
S&P 500 Index**				6.04	%		26.46	%		-5.63	%		0.42	%		-0.95	%		10.54	%
Lipper Small-Cap Core Funds Index				4.49	%		34.50	%		-4.06	%		1.55	%		5.24	%		NA
Lipper Mid-Cap Growth Funds Index				5.65	%		42.65	%		-1.04	%		3.35	%		-1.47	%		NA
Columbia Acorn International (ACINX) (9/23/92)		$34.26		4.32%			50.97%			-1.42%			9.44%			4.75%			11.58%
S&P Global Ex-U.S. Between $500 Million and $5 Billion Index				3.46	%		55.49	%		-2.02	%		8.16	%		7.81	%		8.65	%
S&P Global Ex-U.S. SmallCap Index				3.07	%		56.84	%		-4.03	%		7.12	%		6.98	%		7.86	%
MSCI EAFE Index				2.18	%		31.78	%		-6.04	%		3.54	%		1.17	%		6.16	%
Lipper International Small/ Mid Growth Funds Index				3.73	%		54.44	%		-4.79	%		7.01	%		3.54	%		NA
Columbia Acorn USA (AUSAX) (9/4/96)		$23.19		5.99%			41.49%			-3.82%			1.71%			5.50%			9.68%
Russell 2000 Index				3.87	%		27.17	%		-6.07	%		0.51	%		3.51	%		6.23	%
Russell 2500 Index				5.08	%		34.39	%		-4.86	%		1.58	%		4.91	%		7.93	%
S&P 500 Index**				6.04	%		26.46	%		-5.63	%		0.42	%		-0.95	%		5.90	%
Lipper Small-Cap Growth Funds Index				5.29	%		38.04	%		-4.58	%		0.25	%		-0.63	%		4.46	%
Columbia Acorn Int'l Select (ACFFX) (11/23/98)		$23.64		4.65%			31.52%			-2.46%			7.96%			3.05%			9.35%
S&P Developed Ex-U.S. Between $2 Billion and $10 Billion Index				1.14	%		38.60	%		-6.07	%		4.99	%		5.59	%		7.36	%
MSCI EAFE Index				2.18	%		31.78	%		-6.04	%		3.54	%		1.17	%		3.63	%
Lipper International Funds Index				2.57	%		35.30	%		-4.49	%		4.88	%		1.95	%		4.94	%
Columbia Acorn Select (ACTWX) (11/23/98)		$23.38		7.79%			66.17%			-2.66%			4.16%			7.76%			10.14%
S&P MidCap 400 Index				5.56	%		37.38	%		-1.83	%		3.27	%		6.36	%		8.04	%
S&P 500 Index**				6.04	%		26.46	%		-5.63	%		0.42	%		-0.95	%		1.38	%
Lipper Mid-Cap Growth Funds Index				5.65	%		42.65	%		-1.04	%		3.35	%		-1.47	%		4.93	%
Columbia Thermostat Fund (COTZX) (9/25/02)†		$10.80		5.57%			32.29%			-0.10%			3.12%			—			6.56%
S&P 500 Index				6.04	%		26.46	%		-5.63	%		0.42	%		—			6.43	%
Barclays Capital U.S. Aggregate Bond Index				0.20	%		5.93	%		6.04	%		4.97	%		—			4.83	%
Lipper Flexible Portfolio Funds Index				3.97	%		29.17	%		-0.32	%		3.50	%		—			7.51	%
50/50 Blended Benchmark††				3.13	%		16.34	%		0.52	%		2.99	%		—			5.93	%

*Not annualized.

**The comparison to the S&P 500 Index is presented to show performance against a widely recognized market index over the life of the Fund.

Performance data quoted represents past performance and current performance may be lower or higher. Past performance is no guarantee of future results. The investment return and principal value of an investment in a Fund will fluctuate so that Fund shares, when redeemed, may be worth more or less than their original cost. Please visit columbiafunds.com for daily and most recent month-end updates.

Net asset value (NAV) returns do not include sales charges or contingent deferred sales charges (CDSC). If they were included, returns would have been lower. Class Z shares are sold only at NAV with no Rule 12b-1 fee. Only eligible investors may purchase Class Z shares of the Funds, directly or by exchange. Please see each Fund's prospectus for eligibility and other details. Class Z shares have limited eligibility and the investment minimum requirement may vary.

Performance results reflect any fee waivers or reimbursements of Fund expenses by the investment advisor and/or any of its affiliates. Absent these fee waivers or expense reimbursement arrangements, performance results would have been lower.

Annual operating expense ratios are as stated in each Fund's current prospectus and differences in expense ratios disclosed elsewhere in this report may result from including fee waivers and expense reimbursements as well as different time periods used in calculating the ratios. Columbia Acorn Fund Class Z: 0.76%. Columbia Acorn International Class Z: 0.96%. Columbia Acorn USA Class Z: 1.01%. Columbia Acorn International Select Class Z: 1.21%. Columbia Acorn Select Class Z: 0.95%. Columbia Thermostat Fund has a contractual expense waiver or reimbursement that expires April 30, 2010. Expense ratios without and with the contractual waiver, including fees and expenses associated with the Fund's investments in other investment companies, for Class Z shares are 1.05% and 0.97%, respectively. Absent the waiver or reimbursement, performance results would have been lower.

†A "fund of funds" bears its allocable share of the costs and expenses of the underlying funds in which it invests. Such funds are thus subject to two levels of fees and potentially higher expense ratios than would be associated with an investment in a fund that invests and trades directly in financial instruments under the direction of a single manager.

††The 50/50 Blended Benchmark is a custom supplemental benchmark established by the advisor.

All results shown assume reinvestment of distributions and do not reflect the deduction of taxes that a shareholder would pay on fund distributions or on the redemption of fund shares.

Unlike mutual funds, indexes are not actively managed and do not incur fees or expenses. It is not possible to invest directly in an index. For index definitions, see the inside front cover of this report.

The dates in parantheses are the inception dates for each respective Fund.

1

Squirrel Chatter II: Skill and Luck

Research has proven that it is extremely difficult for institutional investors to consistently outperform the stock market. The performance distribution among mutual funds usually looks like a bell shaped curve, with some funds outperforming, many underperforming, and the average fund underperforming its benchmark roughly by its expense ratio. I'm happy to say that the Columbia Acorn Funds have historically outperformed their primary benchmark for most time periods, as you can see on Page 1. But researchers note that there are thousands of mutual funds, and purely random outcomes will lead some funds to outperform. This raises an interesting debate: Do funds that outperform do so due to skill, or due to luck?

We try hard to apply investment skills in managing our Funds. We follow a time-tested approach and have an experienced and highly specialized team of investment professionals picking the stocks in which we invest. However, in order to cover both bases, I decided to also read up on luck. Dr. Richard Wiseman's The Luck Factor¹ discusses his research and provides some common sense approaches that may enable people to become luckier.

Wiseman procured hundreds of volunteers, creating one group of people who considered themselves lucky and another who considered themselves unlucky. He tested conventional notions of luck. As one might expect, the lucky group had no apparent psychic ability; their guesses of upcoming lottery numbers were no better than guesses made by the unlucky group. Superstition was not effective either, as the appearance of a black cat vs. a white cat had no impact on results of a coin toss competition.

Instead, Wiseman concluded that people take specific actions that enable them to be lucky and succeed. He provides four principles that induce luck:

1)   Maximize your chance opportunities

2)   Listen to your lucky hunches

3)   Expect good fortune

4)   Turn bad luck into good

Though Wiseman does not explicitly mention investing, each principle can be applied in pursuit of successful money management.

Maximizing chance opportunities entails meeting a large number of people and creating networks to obtain information and investment ideas. Being observant and open to new ideas also helps. Successful investments can be discovered inadvertently: years ago I observed long lines and rising prices at parking garages in downtown Chicago and then profitably invested in a parking lot stock. Rather than pursuing information in hope of confirming existing opinions, pursuing unbiased information could induce the sale of an existing stock and purchase of a superior new one.

Listening to lucky hunches requires the use of intuition. Stocks tend to quickly react to information, and acting early, using imperfect information, is indeed an art form. We once had an analyst who tended to act only after obtaining repeated confirmations that company fundamentals had changed. He performed poorly because stocks often moved before he acted. In contrast, we recently successfully invested in a telecommunications stock that appeared likely to rise as an increasing number of Wall Street analysts began following it. Occasionally, we choose not to pursue possible investment opportunities because they simply don't feel right.

The next luck-inducing principle is to expect good fortune. This is consistent with our investment philosophy. We put money into stocks with the expectation that they will make money over time. We tend to expect continued good fortune from our successful investments and, when it makes sense, let our winners run. This has resulted in lower turnover than the industry average for the Columbia Acorn Funds.

We also attempt to turn bad luck into good and pursue an occasional positive side of bad luck. In the 1980s, several of our analysts complained about aggressive foreign competitors hurting companies we held in Columbia Acorn Fund. The portfolio manager at that time, Ralph Wanger, coined the phrase, "Don't bitch, switch!" and we've owned some foreign stocks in Acorn Fund ever since. We've learned that one company's problem may be

2

another company's opportunity, and that the best choice may be to invest in the latter company.

Ben Sherwood's The Survivors Club² also mentions a few attributes applicable to investing. Situational awareness is a key part of military survival training and is important in investing too. Although many homebuilding stocks looked cheap during the housing bubble, generally avoiding them benefited our shareholders. Likewise, a well-run company may perform well within a highly competitive industry, but its stock could have substantial downside if its management changes or it grows beyond its niche.

As defined by Sherwood, the "incredulity response" occurs when very unusual events occur, such as catastrophes. Market meltdowns also appear to qualify. People tend to not believe such an event is happening and become paralyzed. Instead, survivors need to act positively. During a market meltdown, the market becomes extremely risk averse, and pays investors handsomely to take risk. That was true a year ago and we invested in several companies with substantial debt that our analysis indicated would likely survive and flourish. On average, those stocks performed very well for shareholders.

Both authors believe that people can create their own luck. After reading their perspectives, I have to agree. We at Columbia Wanger Asset Management think that creating luck is a skill and that providing above average returns is no random act.

Charles P. McQuaid

President and Chief Investment Officer
Columbia Wanger Asset Management, L.P.

The information and data provided in this analysis are derived from sources that we deem to be reliable and accurate. These views are not guarantees of future performance and involve certain risks, uncertainties and assumptions that are difficult to predict so actual outcomes and results may differ significantly from the views expressed. The views/opinions expressed in "Squirrel Chatter II" are those of the author and not of the Columbia Acorn Trust Board, are subject to change at any time based upon economic, market or other conditions, may differ from views expressed by other Columbia Management associates or other divisions of Bank of America and the respective parties disclaim any responsibility to update such views. These views may not be relied on as investment advice and, because investment decisions for a Columbia Acorn Fund are based on numerous factors, may not be relied on as an indication of trading intent on beha lf of any particular Columbia Acorn Fund.

Stocks of small- and mid-cap companies pose special risks, including possible illiquidity and greater price volatility than stocks of larger, more established companies. International investing involves special risks, including foreign taxation, currency risks, risks associated with possible differences in financial standards and other risks associated with future political and economic developments. Investing in emerging markets may involve greater risks than investing in more developed countries. In addition, concentration of investments in a single region may result in greater volatility. A fund that maintains a relatively concentrated portfolio may be subject to greater risk than a fund that is more fully diversified.

¹  Wiseman, Richard, The Luck Factor, (New York, New York, Miramax Books/Hyperion 2003).

²  Sherwood, Ben, The Survivors Club, (New York, New York, Grand Central Publishing, 2009).

Also referenced in the writing of this essay was a research paper written by Eugene F. Fama and Kenneth R. French titled, "Luck versus Skill in the Cross Section of Mutual Fund Returns." The paper was originally dated October 2007 and updated in November 2009. It can be found on the Social Science Research Network's website at www.ssrn.com.

3

Understanding Your Expenses

As a Fund shareholder, you incur two types of costs. There are transaction costs, which generally include sales charges on purchases and may include redemption or exchange fees. There are also ongoing costs, which generally include investment advisory fees and other Fund expenses. The following information is intended to help you understand your ongoing costs of investing in the Columbia Acorn Funds and to compare these costs with the ongoing costs of investing in other mutual funds.

Analyzing Your Fund's Expenses

To illustrate these ongoing costs, we have provided examples and calculated the expenses paid by investors in the Class Z shares of the Columbia Acorn Funds for the last six months. The information in the following table is based on an initial investment of $1,000, which is invested at the beginning of the reporting period and held for the entire period. Expense information is calculated two ways and each method provides you with different results. The amount listed in the "Actual" column is calculated using each Fund's actual operating expenses and total return for the period. The amount listed in the "Hypothetical" column assumes that the return each year is 5% before expenses and then applies each Fund's actual expense ratio for the period to the hypothetical return. You should not use the hypothetical account values and expenses to estimate either your actual account balance at the end of the period or the expenses you paid during the reporting period. See "Compare With Other Funds" for details on using the hypothetical data.

July 1, 2009 - December 31, 2009

	Account value at the beginning of the period ($)				Account value at the end of the period ($)				Expenses paid during the period ($)				Fund's annualized expense ratio (%)*
Class Z Shares	Actual		Hypothetical		Actual		Hypothetical		Actual		Hypothetical		Actual
Columbia Acorn Fund		1,000.00		1,000.00		1,272.20		1,021.42		4.30		3.82		0.75
Columbia Acorn International		1,000.00		1,000.00		1,244.50		1,020.37		5.43		4.89		0.96
Columbia Acorn USA		1,000.00		1,000.00		1,309.40		1,020.11		5.88		5.14		1.01
Columbia Acorn International Select		1,000.00		1,000.00		1,200.00		1,019.21		6.60		6.06		1.19
Columbia Acorn Select		1,000.00		1,000.00		1,336.00		1,020.37		5.65		4.89		0.96
Columbia Thermostat Fund**		1,000.00		1,000.00		1,228.70		1,023.95		1.40		1.28		0.25

Expenses paid during the period are equal to each Fund's annualized expense ratio, multiplied by the average account value over the period and then multiplied by the number of days in the Fund's most recent fiscal half-year and divided by 365.

It is important to note that the expense amounts shown in the table are meant to highlight only ongoing costs of investing in the Funds and do not reflect any transaction costs, such as sales charges or redemption or exchange fees. Therefore, the hypothetical examples provided may not help you determine the relative total costs of owning different funds. If these transaction costs were included, your costs would have been higher.

Columbia Thermostat Fund's expenses do not include fees and expenses incurred by the Fund from the underlying portfolio funds in which it invests.

*For the six months ended December 31, 2009.

**Had the investment advisor and/or any of its affiliates not waived fees or reimbursed a portion of expenses, account value at the end of the period would have been reduced.

Compare With Other Funds

Since all mutual funds are required to include the same hypothetical calculations about expenses in shareholder reports, you can use this information to compare the ongoing cost of investing in the Funds with other funds. To do so, compare the 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reports of other funds. As you compare hypothetical examples of other funds, it is important to note that hypothetical examples are meant to highlight the continuing costs of investing in a fund and do not reflect any transaction costs, such as sales charges or redemption or exchange fees.

4

Estimating Your Actual Expenses

To estimate the expenses that you actually paid over the period, first you will need your account balance at the end of the period:

•  For shareholders who receive their account statements from Columbia Management Services, Inc., your account balance is available online at columbiafunds.com or by calling Shareholder Services at (800) 922-6769.

•  For shareholders who receive their account statements from their brokerage firm, contact your brokerage firm to obtain your account balance.

1.  Divide your ending account balance by $1,000. For example, if an account balance was $8,600 at the end of the period, the result would be 8.6.

2.  In the section of the table titled "Expenses paid during the period," locate the amount for your Fund. You will find this number is in the column labeled "Actual." Multiply this number by the result from step 1. Your answer is an estimate of the expenses you paid on your account during the period.

5

Columbia Acorn Fund

In a Nutshell

Charles P. McQuaid	Robert A. Mohn
Lead Portfolio Manager	Co-Portfolio Manager

Performance data quoted represents past performance and current performance may be lower or higher. Past performance is no guarantee of future results. The investment return and principal value will fluctuate so that shares, when redeemed, may be worth more or less than the original cost. Please visit columbiafunds.com for daily and most recent month-end performance updates.

Fund Positions
in Mentioned Holdings

As a percentage of net assets,
as of 12/31/09

Crown Castle International	1.7	%
Coach	1.5	%
FMC Technologies	1.2	%
tw telecom	1.1	%
Fugro	1.1	%
Southwestern Energy	1.0	%
Urban Outfitters	1.0	%
Chico's FAS	0.8	%
Atwood Oceanics	0.8	%
J Crew Group	0.8	%
Valley National Bancorp	0.5	%
Pacific Rubiales Energy	0.5	%
Illumina	0.4	%
MB Financial	0.3	%
Associated Banc-Corp	0.3	%

Columbia Acorn Fund jumped 39.65% in 2009, some 5.26% above its primary benchmark, the Russell 2500 Index. During the fourth quarter, the Fund appreciated 5.74%, modestly more than the Russell 2500's 5.08% gain. Additional performance comparisons can be found on Page 1 of this report.

Energy stocks were important contributors to the Fund's performance for the year and the quarter. Offshore oil service providers FMC Technologies, Fugro and Atwood Oceanics all more than doubled during the year on strong revenues and volumes. Oil and gas producers Southwestern Energy and Pacific Rubiales Energy provided 13% and 19% returns in the fourth quarter due to increased production, while XTO Energy rose 16% as its acquisition by Exxon Mobil was announced in December. We sold the Fund's XTO shares on the news.

Telecom stocks were also strong performers. Communications tower company Crown Castle International provided the Fund's largest dollar gains during both periods on a 122% surge for the year, including a 24% gain in the fourth quarter. We had added to holdings in Crown Castle during the credit crunch in late 2008, correctly believing in the company's business model and its ability to service a fairly large debt load. Provider of fiber optic telephone and data services tw telecom doubled during the year and gained 27% in the quarter as its business model proved to be fairly resistant to the recession.

After a tough 2008, retailers cashed in big gains in 2009. J Crew Group more than tripled and Urban Outfitters more than doubled on fine earnings due to strong product lines, market share gains and expense controls. Chico's FAS stock jumped 268% as new management executed a turnaround plan. Handbag designer and marketer Coach bagged a 77% gain for the year as management continued to execute well. All were up between 8% and 25% during the fourth quarter.

As might be expected given its overall results, Columbia Acorn Fund had few large losers in 2009. In the financials sector, Associated Banc-Corp was the largest dollar loser, falling 46% on large credit losses, while MB Financial and Valley National Bancorp fell about half that percentage for much the same reason. While we hate any losses, the Fund's aggregate bank holdings fell 5% in the year, much less than the loss of 22% in the benchmark's bank portfolio. During the quarter, Illumina, a maker of medical devices, was the largest dollar loser, off 28% on a revenue shortfall.

Columbia Acorn Fund's foreign stocks were up 76.73% for the year and 6.84% for the fourth quarter. The foreign portfolio has relatively large weights in energy and materials companies, which have done well. Fugro and Pacific Rubiales Energy, mentioned above, were the top international contributors. At year-end, international stocks made up 11.1% of the Fund.

We spent much of the last 15 months dealing with a volatile stock market and a weak economy. Understanding that smaller caps and more risky stocks have historically tended to recover the most off a deep market bottom, we prudently pursued them. Many of those investments were successful, and now we are pursuing companies that we expect to have good earnings growth. While we are happy with 2009 and fourth quarter performance, we realize that we have still not returned to the Fund's 2008 highs.

Stocks of small- and mid-cap companies pose special risks, including possible illiquidity and greater price volatility than stocks of larger, more established companies. International investing involves special risks, including foreign taxation, currency risks, risks associated with possible differences in financial standards and other risks associated with future political and economic developments.

Portfolio holdings are subject to change periodically and may not be representative of current holdings.

6

Columbia Acorn Fund (ACRNX)

At a Glance

Performance data quoted represents past performance and current performance may be higher or lower. Past performance is no guarantee of future results. The investment return and principal value of an investment in the Fund will fluctuate so that Fund shares, when redeemed, may be worth more or less than their original cost. Performance results reflect any fee waivers or reimbursements of Fund expenses by the investment advisor and/or any of its affiliates. Absent these fee waivers or expense reimbursement arrangements, performance results would have been lower. Please visit columbiafunds.com for daily and most recent month-end updates.

Pretax and After-tax Average Annual Total Returns (Class Z)

through December 31, 2009

Inception 6/10/70	1 year			5 years			10 years
Returns before taxes		39.65	%		3.65	%		7.93	%
Returns after taxes on distributions		39.55			2.89			7.04
Returns after taxes on distributions and sale of fund shares		25.77			3.17			6.76
Russell 2500 Index (pretax)*		34.39			1.58			4.91

All results shown assume reinvestment of distributions.

*The Fund's primary benchmark.

After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect the impact of state and local taxes. Returns after taxes on distributions and sale of Fund shares reflect the additional tax impact of long-term gains or losses realized when Fund shares are sold. The returns are taxed at the maximum rate and assume shares were purchased at the beginning of the period. Actual after-tax returns depend on the investor's tax situation and may differ from those shown. After-tax returns are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts. After-tax returns are shown for Class Z shares only; after-tax returns for other share classes will vary. Indexes do not reflect any deduction for fees, expenses or taxes.

The Fund's Class Z shares annual operating expense ratio, as stated in the current prospectus, is 0.76%.

Columbia Acorn Fund Portfolio Diversification

as a percentage of net assets, as of 12/31/09

Columbia Acorn Fund Top 10 Holdings

as a percentage of net assets, as of 12/31/09

1.	Crown Castle International Communications Towers	1.7%
2.	Coach Designer & Retailer of Branded Leather Accessories	1.5%
3.	Informatica Enterprise Data Integration Software	1.2%
4.	FMC Technologies Oil & Gas Wellhead Manufacturer	1.2%
5.	Donaldson Industrial Air Filtration	1.2%
6.	Amphenol Electronic Connectors	1.2%
7.	Ametek Aerospace/Industrial Instruments	1.2%
8.	Bally Technologies Slot Machines & Software	1.1%
9.	tw telecom Fiber Optic Telephone/Data Services	1.1%
10.	Fugro (Netherlands) Sub-sea Oilfield Services	1.1%

The Fund's top 10 holdings and portfolio diversification vary with changes in portfolio investments. See the Statement of Investments for a complete list of the Fund's holdings.

The Growth of a $10,000 Investment in Columbia Acorn Fund (Class Z)

June 10, 1970 through December 31, 2009

This graph compares the results of $10,000 invested in Columbia Acorn Fund at inception on June 10, 1970 to the S&P 500 Index and to an initial $31,777 investment in the Russell 2500 Index on the index's December 31, 1978 inception date. Although the indexes are provided for use in assessing the Fund's performance, the Fund's holdings may differ significantly from those in the indexes. The indexes are unmanaged and returns for both the indexes and the Fund include reinvested dividends and capital gains. It is not possible to invest directly in an index. The graph does not reflect taxes that a shareholder would pay on Fund distributions or on a sale of Fund shares.

Total Net Assets of the Fund: $14.7 billion

*  A $10,000 investment in Columbia Acorn Fund at inception appreciated to $31,777 on December 31, 1978, the inception date of the Russell 2500 Index. For comparison with the Russell 2500 Index, we assigned the index the same value as the Fund at index inception.

**Although the Fund typically invests in small- and mid-sized companies, the comparison to the S&P 500 Index is presented to show performance against a widely recognized market index over the life of the Fund.

7

Columbia Acorn International

In a Nutshell

P. Zachary Egan	Louis J. Mendes III
Co-Portfolio Manager	Co-Portfolio Manager

Performance data quoted represents past performance and current performance may be lower or higher. Past performance is no guarantee of future results. The investment return and principal value will fluctuate so that shares, when redeemed, may be worth more or less than the original cost. Please visit columbiafunds.com for daily and most recent month-end performance updates.

Fund's Positions
in Mentioned Holdings

As a percentage of net assets,
as of 12/31/09

Naspers	1.8	%
Seven Bank	0.5	%
Wacom	0.4	%

Columbia Acorn International returned 4.32% in the fourth quarter of 2009, 0.86% ahead of its primary benchmark, the S&P Global Ex-U.S. Between $500 Million and $5 Billion Index. The Fund's annual total return of 50.97% trailed its benchmark by 4.52%. Across most markets, share price performance was negatively correlated with size as smaller-capitalized stocks outperformed their larger brethren. The large-cap MSCI EAFE Index returned a relatively modest 31.78%.

We manage Columbia Acorn International with the intention of holding Fund investments for three- to five-years, which is relatively long among international small-cap managers. We believe Fund performance should be considered in this context. A glance at the performance table on Page 1 shows that the Fund's three- and five-year average annual returns were -1.42% and 9.44%, respectively. Both results remain ahead of Fund benchmarks and peer averages.

Much has been written in the financial press about the equity market's return from the precipice after a difficult January and February in 2009. We will not reproduce that discussion here, other than to note that the market rebound generally played out in a fashion consistent with a sudden subsidence of risk aversion across the board. The riskiest equities, including illiquid micro-caps, highly indebted companies and emerging market stocks, led the charge upward. In contrast, lower-risk markets such as Japan, where stocks are cheap, balance sheets overcapitalized and growth expectations generally too anemic to provide cause for disappointment, barely moved. Japanese small- to mid-cap stocks rose a mere 5.6% in U.S. dollar terms in 2009. In this context, it is interesting to look at the winning and losing stocks in the Fund whose performance cannot be explained by changes in how risk is priced alone. This highlights where stock p icking matters.

Fund standouts on the upside included Naspers and Wacom. Naspers is a misunderstood South African-listed media company. With a dominant pay TV franchise in sub-Saharan Africa and a large stake in Tencent, a Hong Kong-listed Internet service provider and gaming company targeting the Chinese market, many investors have been unsure how to analyze the company. Our colleague Fritz Kaegi ferreted out this South African company, which more than doubled in the year and is now the Fund's largest position. Wacom is a Japanese technology company that jumped 155% in 2009 when demand for its pen tablet for professional and consumer applications proved resilient in a weak IT market. The company's new multi-finger touch screen for PCs also has a chance of playing an important role in the next generation of PC user interfaces.

On the downside, the Fund sold its investment in ING Bank Slaski at a 52% annual loss after wrongly judging that the Polish government would intervene in the currency market. This intervention would have let corporations off the hook on costly forward contracts they held with Polish banks. Japanese cash machine network operator Seven Bank, which operates ATMs at convenience stores, ended the year down 47% as investors worried that deflation expectations and weak consumer spending would reduce cash withdrawals and new consumer finance regulations would constrain high margin lending on ATM cards.

International investing may involve certain risks, including currency fluctuations, risks associated with possible differences in financial standards and other monetary and political risks. Significant levels of foreign taxes, including potentially confiscatory levels of taxation and withholding taxes, may also apply to some foreign investments. Stocks of small- and mid-cap companies pose special risks, including possible illiquidity and greater price volatility than stocks of larger, more established companies. Investing in emerging markets may involve greater risks than investing in more developed countries. In addition, concentration of investments in a single region may result in greater volatility.

Portfolio holdings are subject to change periodically and may not be representative of current holdings.

8

Columbia Acorn International (ACINX)

At a Glance

Performance data quoted represents past performance and current performance may be higher or lower. Past performance is no guarantee of future results. The investment return and principal value of an investment in the Fund will fluctuate so that Fund shares, when redeemed, may be worth more or less than their original cost. Performance results reflect any fee waivers or reimbursements of Fund expenses by the investment advisor and/or any of its affiliates. Absent these fee waivers or expense reimbursement arrangements, performance results would have been lower. Please visit columbiafunds.com for daily and most recent month-end updates.

Pretax and After-tax Average Annual Total Returns (Class Z)

through December 31, 2009

Inception 9/23/92	1 year			5 years			10 years
Returns before taxes		50.97	%		9.44	%		4.75	%
Returns after taxes on distributions		49.97			8.52			3.86
Returns after taxes on distributions and sale of fund shares		33.00			8.20			3.88
S&P Global Ex-U.S. Between $500 Million and $5 Billion Index (pretax)*		55.49			8.16			7.81

All results shown assume reinvestment of distributions.

*The Fund's primary benchmark.

After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect the impact of state and local taxes. Returns after taxes on distributions and sale of Fund shares reflect the additional tax impact of long-term gains or losses realized when Fund shares are sold. The returns are taxed at the maximum rate and assume shares were purchased at the beginning of the period. Actual after-tax returns depend on the investor's tax situation and may differ from those shown. After-tax returns are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts. After-tax returns are shown for Class Z shares only; after-tax returns for other share classes will vary. Indexes do not reflect any deduction for fees, expenses or taxes.

The Fund's Class Z annual operating expense ratio, as stated in the current prospectus, is 0.96%.

Columbia Acorn International Portfolio Diversification

as a percentage of net assets, as of 12/31/09

Columbia Acorn International Top 10 Holdings

as a percentage of net assets, as of 12/31/09

1.	Naspers (South Africa) Media in Africa & Other Emerging Markets	1.8%
2.	Olam International (Singapore) Agriculture Supply Chain Manager	1.5%
3.	Eldorado Gold (Canada) Gold Miner in Turkey, Greece, China & Brazil	1.3%
4.	Serco (United Kingdom) Facilities Management	1.2%
5.	Localiza Rent A Car (Brazil) Car Rental	1.2%
6.	Hexagon (Sweden) Measurement Equipment	1.2%
7.	Kansai Paint (Japan) Paint Producer in Japan, India, China & Southeast Asia	1.2%
8.	Imtech (Netherlands) Electromechanical & ICT Installation & Maintenance	1.1%
9.	Suzano (Brazil) Brazilian Pulp & Paper Producer	1.1%
10.	Atwood Oceanics (United States) Offshore Drilling Contractor	1.1%

The Fund's top 10 holdings and portfolio diversification vary with changes in portfolio investments. See the Statement of Investments for a complete list of the Fund's holdings.

The Growth of a $10,000 Investment in Columbia Acorn International (Class Z)

September 23, 1992 through December 31, 2009

This graph compares the results of $10,000 invested in Columbia Acorn International at inception on September 23, 1992 to the S&P Global Ex-U.S. Between $500 Million and $5 Billion Index. Although the index is provided for use in assessing the Fund's performance, the Fund's holdings may differ significantly from those in the index. The index is unmanaged and returns for both the index and Fund include reinvested dividends and capital gains. It is not possible to invest directly in an index. The graph does not reflect taxes that a shareholder would pay on Fund distributions or on a sale of Fund shares.

Total Net Assets of the Fund: $4.4 billion

9

Columbia Acorn USA

In a Nutshell

Robert A. Mohn

Lead Portfolio Manager

Performance data quoted represents past performance and current performance may be lower or higher. Past performance is no guarantee of future results. The investment return and principal value will fluctuate so that shares, when redeemed, may be worth more or less than the original cost. Please visit columbiafunds.com for daily and most recent month-end performance updates.

Fund Positions
in Mentioned Holdings

As a percentage of net assets,
as of 12/31/09

Crown Castle International	3.5	%
tw telecom	2.5	%
FMC Technologies	2.1	%
Atwood Oceanics	1.9	%
AmeriCredit	1.6	%
Donaldson	1.4	%
ITT Educational Services	1.3	%
World Acceptance	1.1	%
Valley National Bancorp	1.0	%
Switch & Data Facilities	0.7	%
MB Financial	0.7	%
Human Genome Sciences	0.7	%
Lakeland Financial	0.5	%
Pacific Continental	0.4	%
True Religion Apparel	0.4	%
Berkshire Hills Bancorp	0.4	%
Illumina	0.3	%
Psychiatric Solutions	0.3	%
Cephalon	0.3	%
Associated Banc-Corp	0.2	%

Columbia Acorn USA ended the fourth quarter of 2009 up 5.99%, outperforming the 3.87% gain of its primary benchmark, the Russell 2000 Index. For the year, the Fund strongly outperformed the Russell 2000 with a 41.49% return vs. a 27.17% annual gain for the index. While we are happy with 2009 performance, we realize that we have still not returned to the Fund's 2008 highs.

Fund telecommunication stocks continued to perform well in the fourth quarter. Both Crown Castle International, an owner of communications towers, and tw telecom, a provider of fiber optic telephone and data services, had solid revenue growth despite the Great Recession. These stocks both were up roughly 25% for the quarter and ended the year up over 100%.

Our holdings of companies in the consumer finance sector were also strong in the quarter as these stocks benefited from the disappearance of many of their competitors. World Acceptance, a provider of smaller personal loans, saw its earnings grow 48% year-over-year through September and announced a decrease in credit losses. Its stock gained 42% in the fourth quarter. Several large banks have completely withdrawn from the business of making used auto loans, and this reduction in supply has contributed to boosted lending spreads for surviving lenders such as AmeriCredit. AmeriCredit enjoyed a 21% gain in the fourth quarter and ended the year up 149%.

Biotech company Human Genome Sciences continued its strong run in the fourth quarter, posting a 62% gain after announcing additional positive results from its lupus drug trials. Its annual gain was a whopping 840%. Switch & Data Facilities, a provider of data center and Internet exchange services, gained 49% in the quarter and 179% for the year on news that it would be acquired by Equinix, a provider of data center operations and infrastructure services. Donaldson, a maker of industrial air filters, gained 23% in the quarter as the company controlled costs and increased its market share.

Top contributors to the Fund's annual performance were energy stocks FMC Technologies, an oil and gas wellhead manufacturer, and Atwood Oceanics, an offshore drilling contractor. Both had annual gains of over 140% as the industry's focus on deep sea drilling fueled growth in their businesses.

On the downside for the quarter, ITT Educational Services, a provider of post-secondary degree programs, fell 13% as student debt defaults showed signs of increasing. Premium denim retailer True Religion Apparel and Illumina, a maker of medical devices, reported disappointing third quarter sales, sending both companies' stocks down roughly 28%. Psychiatric Solutions, a provider of behavioral health services, fell 23% in the quarter and 26% for the year. Its business was hurt by an increase in the percentage of its patients who were uninsured.

Six of the 15 biggest detractors to performance in the Fund for the year were regional banks. MB Financial, Valley National Bancorp, Lakeland Financial, Berkshire Hills Bancorp, Associated Banc-Corp and Pacific Continental were all down between 22% and 46%. Losses on commercial loans held by these banks accelerated throughout the year, particularly on loans tied to new residential developments. Another laggard for the year was pharmaceutical company Cephalon, which was off nearly 20% in the Fund. Several of Cephalon's drug patents will expire soon, making way for competition from generics.

This past year started off with tremendous uncertainty but we were able to take advantage of the volatility in the market to make some opportunistic purchases of beaten down stocks. As we move into a new year, we plan to focus on finding stocks in smaller, niche companies, which we believe have good growth prospects and trade at attractive prices.

Stocks of small- and mid-cap companies pose special risks, including possible illiquidity and greater price volatility than stocks of larger, more established companies.

Portfolio holdings are subject to change periodically and may not be representative of current holdings.

10

Columbia Acorn USA (AUSAX)

At a Glance

Performance data quoted represents past performance and current performance may be higher or lower. Past performance is no guarantee of future results. The investment return and principal value of an investment in the Fund will fluctuate so that Fund shares, when redeemed, may be worth more or less than their original cost. Performance results reflect any fee waivers or reimbursements of Fund expenses by the investment advisor and/or any of its affiliates. Absent these fee waivers or expense reimbursement arrangements, performance results would have been lower. Please visit columbiafunds.com for daily and most recent month-end updates.

Pretax and After-tax Average Annual Total Returns (Class Z)

through December 31, 2009

Inception 9/4/96	1 year			5 years			10 years
Returns before taxes		41.49	%		1.71	%		5.50	%
Returns after taxes on distributions		41.49			1.20			5.14
Returns after taxes on distributions and sale of fund shares		26.97			1.50			4.79
Russell 2000 Index (pretax)*		27.17			0.51			3.51

All results shown assume reinvestment of distributions.

*The Fund's primary benchmark.

After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect the impact of state and local taxes. Returns after taxes on distributions and sale of Fund shares reflect the additional tax impact of long-term gains or losses realized when Fund shares are sold. The returns are taxed at the maximum rate and assume shares were purchased at the beginning of the period. Actual after-tax returns depend on the investor's tax situation and may differ from those shown. After-tax returns are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts. After-tax returns are shown for Class Z shares only; after-tax returns for other share classes will vary. Indexes do not reflect any deduction for fees, expenses or taxes.

The Fund's Class Z annual operating expense ratio, as stated in the current prospectus, is 1.01%.

Columbia Acorn USA Portfolio Diversification

as a percentage of net assets, as of 12/31/09

Columbia Acorn USA Top 10 Holdings

as a percentage of net assets, as of 12/31/09

1.	Crown Castle International Communications Towers	3.5%
2.	tw telecom Fiber Optic Telephone/Data Services	2.5%
3.	Informatica Enterprise Data Integration Software	2.1%
4.	FMC Technologies Oil & Gas Wellhead Manufacturer	2.1%
5.	Atwood Oceanics Offshore Drilling Contractor	1.9%
6.	Global Payments Credit Card Processor	1.8%
7.	Ametek Aerospace/Industrial Instruments	1.7%
8.	Bally Technologies Slot Machines & Software	1.7%
9.	Nordson Dispensing Systems for Adhesives & Coatings	1.6%
10.	AmeriCredit Auto Lending	1.6%

The Fund's top 10 holdings and portfolio diversification vary with changes in portfolio investments. See the Statement of Investments for a complete list of the Fund's holdings.

The Growth of a $10,000 Investment in Columbia Acorn USA (Class Z)

September 4, 1996 through December 31, 2009

This graph compares the results of $10,000 invested in Columbia Acorn USA at inception on September 4, 1996 to the Russell 2000 Index. Although the index is provided for use in assessing the Fund's performance, the Fund's holdings may differ significantly from those in the index. The index is unmanaged and returns for both the index and the Fund include reinvested dividends and capital gains. It is not possible to invest directly in an index. The graph does not reflect taxes that a shareholder would pay on Fund distributions or on a sale of Fund shares.

Total Net Assets of the Fund: $1.4 billion

11

Columbia Acorn International Select

In a Nutshell

Christopher J. Olson

Lead Portfolio Manager

Performance data quoted represents past performance and current performance may be lower or higher. Past performance is no guarantee of future results. The investment return and principal value will fluctuate so that shares, when redeemed, may be worth more or less than the original cost. Please visit columbiafunds.com for daily and most recent month-end performance updates.

Fund's Positions
in Mentioned Holdings

As a percentage of net assets,
as of 12/31/09

Naspers	6.2	%
Ascendas REIT	2.9	%
Hexagon	2.4	%
Pacific Rubiales Energy	2.2	%
Jupiter Telecommunications	2.2	%
Potash Corp. of Saskatchewan	2.1	%
Benesse	1.9	%
Rohto Pharmaceutical	1.8	%
Seven Bank	1.7	%
Ain Pharmaciez	0.9	%
Kamigumi	0.8	%

Columbia Acorn International Select ended the fourth quarter up 4.65% while its primary benchmark, the S&P Developed Ex-U.S. Between $2 Billion and $10 Billion Index, gained 1.14%. For the year ended December 31, 2009, the Fund had a 31.52% return while its benchmark was up 38.60%. Having positioned the Fund well for the previous downturn, the Fund lagged over the past year as the markets were boosted by an unprecedented amount of monetary and fiscal stimulus. Our focus for the Fund has been on companies with competitive market positions and business models, longer-term growth prospects and solid balance sheets, but these companies were not strong performers during 2009 as investor appetite for risk returned and lower quality stocks rallied. We intend to continue to manage the Fund following the approach that has resulted in good outperformance relative to its benchmark and peers over the past three- and five-year periods.

Naspers was the top dollar contributor to Fund performance for the quarter and for the year. Its stock rose 18% in the fourth quarter and ended the year up 121%. Naspers is a media company with assets in South Africa and other emerging markets that has enjoyed strong earnings growth and has benefited from its stake in the rapidly growing Chinese Internet company, Tencent. Hexagon, a Swedish manufacturer of measurement equipment, gained 23% in the fourth quarter and ended the year up 194%. The company's business fundamentals remained robust throughout the recession due to its strong focus on emerging markets where growth has proven to be more stable.

Canadian potash producer Potash Corp. of Saskatchewan had a 21% gain in the quarter and an annual return of 81% as the market's hope of a bottoming, and subsequently rebounding, potash price fed through to the stock. Ascendas REIT, an industrial property landlord in Singapore, gained 16% in the quarter and ended the year up 75% as the demand for property assets increased with the recovery in Singapore's economy. Canada's Pacific Rubiales Energy, an oil production and exploration company with operating assets in Colombia, gained 19% in the quarter and ended the year up an impressive 680%. The stock has benefited from increasing production and new exploration discoveries in Colombia as well as the rebound in oil prices.

Japanese holdings in the Fund were weak in the fourth quarter as investors flocked to riskier investments and markets. Japan's Seven Bank, Rohto Pharmaceutical, Benesse, Ain Pharmaciez and Kamigumi returned losses ranging from 10% to 20%. Japanese companies were also well represented among the Fund's biggest losers for the annual period, with Jupiter Telecommunications, Nintendo and Seven Bank down between 5% and 30% for the year. We sold out of Nintendo early in the third quarter of 2009. The Japanese economy continues to suffer from a deflationary environment and declining population. While stocks in Japan are beginning to look interesting from a valuation perspective, the growth outlook remains uncertain, and investors reduced their Japanese holdings over the course of the year to focus on companies in other regions. Cephalon, a U.S. pharmaceutical company, was the biggest detractor to the Fund's annual performance, falling m ore than 20% in the Fund. Upcoming patent expirations on several of Cephalon's drugs will make way for competition from generics, and potential health care reform in the United States added to uncertainty about its business. The Fund sold out of its position in Cephalon in the fourth quarter.

International investing may involve certain risks, including currency fluctuations, risks associated with possible differences in financial standards and other monetary and political risks. Significant levels of foreign taxes, including potentially confiscatory levels of taxation and withholding taxes, may also apply to some foreign investments. Stocks of small- and mid-cap companies pose special risks, including possible illiquidity and greater price volatility than stocks of larger, more established companies. Investing in emerging markets may involve greater risks than investing in more developed countries.

Portfolio holdings are subject to change periodically and may not be representative of current holdings.

12

Columbia Acorn International Select (ACFFX)

At a Glance

Performance data quoted represents past performance and current performance may be higher or lower. Past performance is no guarantee of future results. The investment return and principal value of an investment in the Fund will fluctuate so that Fund shares, when redeemed, may be worth more or less than their original cost. Performance results reflect any fee waivers or reimbursements of Fund expenses by the investment advisor and/or any of its affiliates. Absent these fee waivers or expense reimbursement arrangements, performance results would have been lower. Please visit columbiafunds.com for daily and most recent month-end updates.

Pretax and After-tax Average Annual Total Returns (Class Z)

through December 31, 2009

Inception 11/23/98	1 year			5 years			10 years
Returns before taxes		31.52	%		7.96	%		3.05	%
Returns after taxes on distributions		30.97			7.60			2.86
Returns after taxes on distributions and sale of fund shares		20.43			6.95			2.66
S&P Developed Ex-U.S. Between $2 Billion and $10 Billion Index (pretax)*		38.60			4.99			5.59

All results shown assume reinvestment of distributions.

*The Fund's primary benchmark.

After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect the impact of state and local taxes. Returns after taxes on distributions and sale of Fund shares reflect the additional tax impact of long-term gains or losses realized when Fund shares are sold. The returns are taxed at the maximum rate and assume shares were purchased at the beginning of the period. Actual after-tax returns depend on the investor's tax situation and may differ from those shown. After-tax returns are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts. After-tax returns are shown for Class Z shares only; after-tax returns for other share classes will vary. Indexes do not reflect any deduction for fees, expenses or taxes.

The Fund's Class Z annual operating expense ratio, as stated in the current prospectus, is 1.21%.

Columbia Acorn International Select Portfolio Diversification

as a percentage of net assets, as of 12/31/09

Columbia Acorn International Select Top 10 Holdings

as a percentage of net assets, as of 12/31/09

1.	Naspers (South Africa) Media in Africa & Other Emerging Markets	6.2%
2.	Serco (United Kingdom) Facilities Management	4.9%
3.	Capita Group (United Kingdom) White Collar, Back Office Outsourcing	3.2%
4.	NHN (South Korea) South Korea's Largest Online Search Engine	2.9%
5.	Ascendas REIT (Singapore) Singapore Industrial Property Landlord	2.9%
6.	Olam International (Singapore) Agriculture Supply Chain Manager	2.8%
7.	Red Electrica de Espana (Spain) Spanish Power Transmission	2.6%
8.	Cobham (United Kingdom) Aerospace Components	2.6%
9.	Kansai Paint (Japan) Paint Producer in Japan, India, China & Southeast Asia	2.6%
10.	Intertek Group (United Kingdom) Testing, Inspection & Certification Services	2.6%

The Fund's top 10 holdings and portfolio diversification vary with changes in portfolio investments. See the Statement of Investments for a complete list of the Fund's holdings.

The Growth of a $10,000 Investment in Columbia Acorn International Select (Class Z)

November 23, 1998 through December 31, 2009

This graph compares the results of $10,000 invested in Columbia Acorn International Select at inception on November 23, 1998 to the S&P Developed Ex-U.S. Between $2 Billion and $10 Billion Index. Although the index is provided for use in assessing the Fund's performance, the Fund's holdings may differ significantly from those in the index. The index and Fund returns include reinvested dividends and capital gains. It is not possible to invest directly in an index. The graph does not reflect taxes that a shareholder would pay on Fund distributions or on a sale of Fund shares.

Total Net Assets of the Fund: $410.7 million

13

Columbia Acorn Select

In a Nutshell

Ben Andrews

Lead Portfolio Manager

Performance data quoted represents past performance and current performance may be lower or higher. Past performance is no guarantee of future results. The investment return and principal value will fluctuate so that shares, when redeemed, may be worth more or less than the original cost. Please visit columbiafunds.com for daily and most recent month-end performance updates.

Fund's Positions
in Mentioned Holdings

As a percentage of net assets,
as of 12/31/09

ITT Educational Services	4.9	%
Pacific Rubiales Energy	4.9	%
Sanmina-SCI	4.7	%
Safeway	3.9	%
Expedia	3.4	%
Canadian Solar	2.8	%
American Commercial Lines	1.1	%
Houston American Energy	0.3	%
GLG Life Tech	0.0	%*
Fu Ji Food & Catering Services	0.0	%*
ChemSpec International	0.0	%*

*Rounds to less than 0.1%.

Columbia Acorn Select gained 7.79% in the fourth quarter of 2009. This exceeded the 5.56% rise in the Fund's primary benchmark, the S&P MidCap 400 Index. For the year, the Fund outperformed its benchmark by almost 29 percentage points with a 66.17% gain vs. a 37.38% return for the S&P MidCap 400 Index. We are pleased that we could offer our shareholders such strong performance. The S&P 500 Index, which is a large-cap index, trailed mid-caps with a 26.46% annual return.

The Fund's top two dollar winners for the fourth quarter were Canadian Solar, a solar-power equipment manufacturer, and Sanmina-SCI, a provider of electronic manufacturing services, which together added almost 2.6% to the Fund's performance. The two top dollar losers for the quarter were American Commercial Lines, a barge operator and builder, and ITT Educational Services, a provider of post-secondary degree programs, which together cost the Fund 1.6% of performance. For the year, Pacific Rubiales Energy, an oil production and exploration company, Sanmina-SCI and Expedia, a provider of online travel services, contributed about 20% of the Fund's 66% return. On the downside, pharmaceutical company Cephalon, supermarket chain Safeway and Chinese caterer Fu Ji Food & Catering Services together cost the Fund about 3% of its yearly portfolio return. We sold the Fund's position in Cephalon in the first half of the year.

During the fourth quarter, we added three new companies to the Fund's portfolio. The new investments were GLG Life Tech, ChemSpec International and Houston American Energy. GLG Life Tech produces an all natural, zero calorie sweetener made from the stevia plant. ChemSpec is a fluorinated specialty chemicals manufacturer, and Houston American Energy is an oil and gas exploration and production company with its primary operations in Colombia.

During the quarter we sold the Fund's position in Donaldson, a maker of industrial air filters, FMC Technologies, an oil and gas wellhead manufacturer, and retailer The Gap Stores. We sold down or out of the Fund's larger oil service/production companies while investing the dollars back into smaller oil companies, primarily those located in Colombia.

The U.S. economy is continuing to recover as we enter 2010, but unemployment remains high. However, I believe failure to pass a carbon tax and/or health care legislation could benefit both the economy and the market as it would clear away uncertainty, which is restraining job growth within two of this country's largest employing industries: industrials/oil/utilities and health care. I believe employment could also get a boost if the government chooses not to let the sun setting tax cuts, which are estimated to account for approximately 2% of GDP—a significant figure in an economy with over 10% unemployment—expire at the end of 2010. If these scenarios evolve, employment could rebound. Until then, our focus will be to find stocks that we believe can perform well in a slower growth environment.

Risks include stock market fluctuations due to economic and business developments. The Fund also has potentially greater price volatility due to the Fund's concentration in a limited number of stocks of mid-size companies. The Fund is a non-diversified fund and may, therefore, have a greater risk of loss from a few issuers than a similar fund that invests more broadly. The Fund may not operate as a non-diversified fund at all times. International investments involve greater potential risks, including less regulation, currency fluctuations, economic instability and political developments.

Portfolio holdings are subject to change periodically and may not be representative of current holdings.

14

Columbia Acorn Select (ACTWX)

At a Glance

Performance data quoted represents past performance and current performance may be higher or lower. Past performance is no guarantee of future results. The investment return and principal value of an investment in the Fund will fluctuate so that Fund shares, when redeemed, may be worth more or less than their original cost. Performance results reflect any fee waivers or reimbursements of Fund expenses by the investment advisor and/or any of its affiliates. Absent these fee waivers or expense reimbursement arrangements, performance results would have been lower. Please visit columbiafunds.com for daily and most recent month-end updates.

Pretax and After-tax Average Annual Total Returns (Class Z)

through December 31, 2009

Inception 11/23/98	1 year			5 years			10 years
Returns before taxes		66.17	%		4.16	%		7.76	%
Returns after taxes on distributions		66.17			3.84			7.33
Returns after taxes on distributions and sale of fund shares		43.01			3.59			6.73
S&P MidCap 400 Index (pretax)*		37.38			3.27			6.36

All results shown assume reinvestment of distributions.

*The Fund's primary benchmark.

After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect the impact of state and local taxes. Returns after taxes on distributions and sale of Fund shares reflect the additional tax impact of long-term gains or losses realized when Fund shares are sold. The returns are taxed at the maximum rate and assume shares were purchased at the beginning of the period. Actual after-tax returns depend on the investor's tax situation and may differ from those shown. After-tax returns are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts. After-tax returns are shown for Class Z shares only; after-tax returns for other share classes will vary. Indexes do not reflect any deduction for fees, expenses or taxes.

The Fund's Class Z annual operating expense ratio, as stated in the current prospectus, is 0.95%.

Columbia Acorn Select Portfolio Diversification

as a percentage of net assets, as of 12/31/09

Columbia Acorn Select Top 10 Holdings

as a percentage of net assets, as of 12/31/09

1.	ITT Educational Services Post-secondary Degree Services	4.9%
2.	Pacific Rubiales Energy (Canada) Oil Production & Exploration in Colombia	4.9%
3.	SkillSoft Web-based Learning Solutions (E-Learning)	4.8%
4.	Sanmina-SCI Electronic Manufacturing Services	4.7%
5.	Hertz Largest U.S. Rental Car Operator	4.6%
6.	Safeway Supermarkets	3.9%
7.	Conseco Life, Long-term Care & Medical Supplement Insurance	3.5%
8.	Expedia Online Travel Services Company	3.4%
9.	Crown Castle International Communications Towers	3.1%
10.	WNS (India) Offshore BPO (Business Process Outsourcing) Services	3.0%

The Fund's top 10 holdings and portfolio diversification vary with changes in portfolio investments. See the Statement of Investments for a complete list of the Fund's holdings.

The Growth of a $10,000 Investment in Columbia Acorn Select (Class Z)

November 23, 1998 through December 31, 2009

This graph compares the results of $10,000 invested in Columbia Acorn Select at inception on November 23, 1998 to the S&P MidCap 400 Index. Although the index is provided for use in assessing the Fund's performance, the Fund's holdings differ significantly from those in the index. The index is unmanaged and returns for both the index and the Fund include reinvested dividends and capital gains. It is not possible to invest directly in an index. The graph does not reflect taxes that a shareholder would pay on Fund distributions or on a sale of Fund shares.

Total Net Assets of the Fund: $1.9 billion

15

Columbia Thermostat Fund

In a Nutshell

Charles P. McQuaid

Lead Portfolio Manager

Performance data quoted represents past performance and current performance may be lower or higher. Past performance is no guarantee of future results. The investment return and principal value will fluctuate so that shares, when redeemed, may be worth more or less than the original cost. Please visit columbiafunds.com for daily and most recent month-end performance updates.

A "fund of funds" bears its allocable share of the costs and expenses of the underlying funds in which it invests. Such funds are thus subject to two levels of fees and potentially higher expense ratios than would be associated with a fund that invests and trades directly in financial instruments under the direction of a single manager.

Columbia Thermostat Fund ended the fourth quarter up 5.57%, outperforming the 0.20% gain of the Barclays Capital U.S. Aggregate Bond Index, the Fund's primary bond benchmark, and underperforming the 6.04% return of the S&P 500 Index, the Fund's primary stock benchmark. For the year, the Fund's 32.29% return topped both indexes. The S&P 500 Index had an annual return of 26.46% and the Barclays Capital U.S. Aggregate Bond Index was up 5.93%.

We recently conducted a review of the structure, allocation percentages and underlying funds that comprise Columbia Thermostat Fund and, as a result of this review, we have made some changes to the Fund's structure. These changes went into effect on January 13, 2010, just after the period covered by this report. The specifics of these investment strategy changes are summarized below:

• We implemented a 90% maximum and a 10% minimum for both stock and bond allocations.

• The allocation of the Fund's assets among underlying stock and bond funds set forth in the Stock/Bond Allocation table in the Fund's prospectus has been modified in two additional ways. First, the increment in the S&P 500 Index that triggers a change in allocation has decreased from 60 to 50 points. Second, the range of the S&P 500 Index has been reduced so that allocations become static when the S&P 500 Index is at 1,000 and under (rather than 960 and under) or over 1,750 (rather than over 2,100).

• Consequently, the Fund now has a smaller percentage of assets in stock funds at the current level of the S&P 500 Index.

• The tighter range and smaller percentage in stock funds reflects our opinion that S&P500 Index earnings and valuations will be lower than we previously expected.

• Believing that many foreign economies are likely to grow faster than the U.S. economy, we increased the stock fund allocation to Columbia Acorn International from 15% to 20%.

• To make room for additional international holdings, we reduced the stock fund allocation to the large-cap blend asset class from 25% to 20%.

• Within the large-cap blend asset class, we added Columbia Contrarian Core Fund as an underlying investment option and will split this allocation with Columbia Large Cap Enhanced Core Fund. Columbia Contrarian Core Fund has a fine track record and currently a greater bias towards growth stocks than Columbia Large Cap Enhanced Core Fund.

Results of the Funds Owned in Columbia Thermostat Fund as of December 31, 2009

Stock Funds Fund	Weightings in category			4th quarter			1 year
Columbia Acorn Fund		15	%		5.74	%		39.65	%
Columbia Acorn Select		10	%		7.79	%		66.17	%
Columbia Marsico Growth Fund		15	%		6.56	%		29.37	%
Columbia Acorn International		15	%		4.32	%		50.97	%
Columbia Dividend Income Fund		20	%		6.82	%		18.59	%
Columbia Large Cap Enhanced Core Fund		25	%		6.11	%		23.99	%
Weighted Average Equity Return/Loss		100	%		6.20	%		33.80	%
Bond Funds Fund	Weightings in category			4th quarter			1 year
Columbia Intermediate Bond Fund		50	%		2.08	%		19.11	%
Columbia U.S. Treasury Index Fund		30	%		-1.30	%		-3.77	%
Columbia Conservative High Yield Fund		20	%		4.21	%		34.96	%
Weighted Average Income Return		100	%		1.49	%		14.74	%

Columbia Thermostat Fund
Rebalancing in the Fourth Quarter

October 15, 2009 85% stocks, 15% bonds

The combination of our change in the allocation table and market movement resulted in Columbia Thermostat Fund having 70% in stock funds and 30% in bond funds as of press time on February 19, 2010.

The value of an investment in the Fund is based primarily on the performance of the underlying portfolio funds and the allocation of the Fund's assets among them. An investment in the underlying portfolio funds may present certain risks, including stock market fluctuations that occur in response to economic and business developments; and a greater degree of social, political and economic volatility associated with international investing. Stocks of small- and mid-cap companies pose special risks, including possible illiquidity and greater price volatility than stocks of larger, more established companies. Value stocks may also be subject to specific business risks that have caused the stocks to be out of favor. Lower-rated and medium quality debt securities are more speculative and incur more risk. International investing may involve certain risks, including currency fluctuations, risks associated with possible differences in financial standards and other monetary and political risks. Significant levels of foreign taxes, including potentially confiscatory levels of taxation and withholding taxes, may also apply to some foreign investments. Changes in interest rates and changes in the financial strength of issuers of lower-rated bonds may also affect underlying fund performance. The Fund is also subject to the risk that the investment advisor's decisions regarding asset classes and underlying portfolio funds will not anticipate market trends successfully, resulting in a failure to preserve capital or lower total return. In addition, the Fund may buy and sell shares of the portfolio funds frequently. This may result in higher transaction costs and additional tax liability. This is not an offer of the shares of any other mutual fund mentioned herein.

16

Columbia Thermostat Fund (COTZX)

At a Glance

Performance data quoted represents past performance and current performance may be higher or lower. Past performance is no guarantee of future results. The investment return and principal value of an investment in the Fund will fluctuate so that Fund shares, when redeemed, may be worth more or less than their original cost. Performance results reflect any fee waivers or reimbursements of Fund expenses by the investment advisor and/or any of its affiliates. Absent these fee waivers or expense reimbursement arrangements, performance results would have been lower. Please visit columbiafunds.com for daily and most recent month-end updates.

Pretax and After-tax Average Annual Total Returns (Class Z)

through December 31, 2009

Inception 9/25/02	1 year			5 year			Life of fund
Returns before taxes		32.29	%		3.12	%		6.56	%
Returns after taxes on distributions		32.14			1.40			5.17
Returns after taxes on distributions and sale of fund shares		20.97			1.97			5.11
S&P 500 Index (pretax)*		26.46			0.42			6.43
Barclays Capital U.S. Aggregate Bond Index (pretax)*		5.93			4.97			4.83
Lipper Flexible Portfolio Funds Index (pretax)		29.17			3.50			7.51

All results shown assume reinvestment of distributions.

*The Fund's primary stock and bond benchmarks, respectively.

After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect the impact of state and local taxes. Returns after taxes on distributions and sale of Fund shares reflect the additional tax impact of long-term gains or losses realized when Fund shares are sold. The returns are taxed at the maximum rate and assume shares were purchased at the beginning of the period. Actual after-tax returns depend on the investor's tax situation and may differ from those shown. After-tax returns are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts. After-tax returns are shown for Class Z shares only; after-tax returns for other share classes will vary. Indexes do not reflect any deduction for fees, expenses or taxes.

The Fund's Class Z annual operating expense ratio, as stated in the current prospectus, reflects a contractual expense waiver or reimbursement that expires April 30, 2010. Expense ratios without and with the contractual waiver, including fees and expenses associated with the Fund's investment in other investment companies, are 1.05% and 0.97%, respectively. Absent the waiver or reimbursement, performance results would have been lower.

Columbia Thermostat Fund Asset Allocation

as a percentage of net assets, as of 12/31/09

Columbia Thermostat Fund Portfolio Weightings

as a percentage of assets in each investment category, as of 12/31/09

Stock Mutual Funds

Columbia Large Cap Enhanced Core Fund, Class Z	25	%
Columbia Dividend Income Fund, Class Z	20	%
Columbia Acorn Fund, Class Z	15	%
Columbia Acorn International, Class Z	15	%
Columbia Marsico Growth Fund, Class Z	15	%
Columbia Acorn Select, Class Z	10	%

Bond Mutual Funds

Columbia Intermediate Bond Fund, Class Z	50	%
Columbia U.S. Treasury Index Fund, Class Z	30	%
Columbia Conservative High Yield Fund, Class Z	20	%

The Growth of a $10,000 Investment in Columbia Thermostat Fund (Class Z)

September 25, 2002 through December 31, 2009

This graph compares the results of $10,000 invested in Columbia Thermostat Fund at inception on September 25, 2002 to the S&P 500 Index, the Barclays Capital U.S. Aggregate Bond Index and the Lipper Flexible Portfolio Funds Index ("Lipper Index"). Although the indexes are provided for use in assessing the Fund's performance, the Fund's holdings differ significantly from those in the indexes. The Indexes are unmanaged (although the funds that comprise the Lipper Index are managed) and returns for the indexes and the Fund include reinvested dividends and capital gains. It is not possible to invest directly in an index. The graph does not reflect taxes that a shareholder would pay on Fund distributions or on a sale of Fund shares.

Total Net Assets of the Fund: $138.6 million

17

Columbia Acorn Fund

Major Portfolio Changes in the Fourth Quarter (Unaudited)

	Number of Shares
	09/30/09		12/31/09
Purchases
Information
AboveNet		500,000		600,000
ANSYS		1,795,000		2,083,291
Art Technology Group		885,000		2,594,654
Blackboard		0		109,007
Blue Coat Systems		786,000		1,534,000
Discovery Communications, Series C		2,636,500		4,070,000
Eutelsat (France)		250,000		400,000
ExlService Holdings		0		747,658
F5 Networks		920,000		1,045,000
Mettler Toledo		1,385,000		1,450,000
Monolithic Power Systems		745,000		870,000
PAETEC Holding		8,500,000		9,600,000
Plexus		1,275,000		1,395,000
Tyler Technologies		632,890		1,134,260
Consumer Goods & Services
Abercrombie & Fitch		2,715,000		4,500,000
Charming Shoppes		5,857,967		7,500,000
Chico's FAS		7,767,000		8,514,272
Diamond Foods		0		550,475
Flowers Foods		497,511		819,000
GLG Life Tech (Canada)		0		1,153,700
Hansen Natural		1,600,000		1,802,600
Hyatt Hotels		0		141,800
Rue21		0		146,390
Smart Balance		2,500,000		3,000,000
Steelcase		2,612,606		3,000,000
Industrial Goods & Services
Airgas		2,275,000		2,555,200
GrafTech International		1,050,000		1,680,000
Jain Irrigation Systems (India)		440,416		1,000,000
Pall		2,000,000		2,150,000
Silgan Holdings		0		200,000
TrueBlue		800,000		924,900
Finance
City National		170,000		295,000
CVB Financial		0		830,700
Eagle Bancorp		0		251,000
Hanover Insurance Group		615,000		849,000
Hudson Valley		0		660,000
Leucadia National		2,220,000		2,427,400
Pacific Continental		0		246,505
SVB Financial Group		960,000		1,172,396
Health Care
Acorda Therapeutics		0		1,300,000
Allos Therapeutics		1,800,000		2,800,000

	Number of Shares
	09/30/09		12/31/09
Allscripts-Misys Healthcare		0		700,000
AthenaHealth		0		250,000
Auxilium Pharmaceuticals		1,250,000		1,350,000
BioMarin		3,000,000		3,250,000
Gen-Probe		0		568,910
Nanosphere		0		1,232,900
PSS World Medical		2,300,000		2,750,000
Seattle Genetics		3,250,000		4,117,700
Sirona Dental Systems		650,500		850,000
Energy & Minerals
Alange Energy (Colombia)		156,500		8,435,000
Baytex (Canada)		0		347,600
Cabot Oil & Gas		0		250,000
Houston American Energy		0		1,200,000
Orko Silver (Canada)		3,500,000		10,000,000
Pan Orient (Canada)		418,500		1,198,100
Cap-Link Ventures		0		24,000,000
Cap-Link Ventures-Warrants		0		24,000,000
PolyMet Mining		1,000,000		1,500,000
Royal Gold		400,000		500,000
STR Holdings		0		400,000
Zhaojin Mining Industry (China)		0		6,333,700
Other Industries
BioMed Realty Trust		1,360,000		2,260,902
Macerich		865,037		880,376
Old Dominion Freight Lines		0		150,000
Terna (Italy)		0		3,500,000

See accompanying notes to financial statements.

18

	Number of Shares
	09/30/09		12/31/09
Sales
Information
American Tower		1,500,000		1,200,000
Cogent Communications		4,300,000		4,200,000
Concur Technologies		1,400,000		1,200,000
Dionex		500,000		400,000
Discovery Communications		1,433,200		0
Dolby Laboratories		1,340,000		1,140,000
FARO Technologies		334,074		0
Intermec		500,000		0
Micros Systems		2,750,544		2,050,544
ON Semiconductor		4,059,000		3,584,000
Quality Systems		902,110		800,000
Radiant Systems		2,204,336		1,000,000
Red Hat		2,000,000		1,000,000
SES (France)		893,000		702,000
Trimble Navigation		1,770,000		1,545,000
Varian		200,000		0
Vasco Data Security International		154,749		0
Consumer Goods & Services
American Apparel		342,382		0
Career Education		1,700,000		1,677,000
Champion Enterprises		4,500,000		0
Choice Hotels		1,700,000		1,300,000
GameStop		1,650,000		0
Herman Miller		3,500,000		2,800,000
HNI		870,000		0
Hot Topic		3,308,890		0
Jarden		2,500,000		1,700,000
Winnebago Industries		650,000		0
Industrial Goods & Services
Aalberts Industries (Netherlands)		2,825,285		2,200,000
Administaff		1,935,000		1,428,224
Clarcor		3,000,000		2,627,500
FreightCar America		225,000		0
Greif		600,000		500,000
Haynes International		390,000		0
Intertek Group (United Kingdom)		299,004		0
Intrepid Potash		275,000		0
Lincoln Electric		350,000		0
Quanta Services		2,300,000		2,070,000
Toro		1,075,000		900,000
Watsco		725,000		625,000
Finance
Assurant		1,530,000		1,200,000
BOK Financial		3,000,000		2,689,000
Eaton Vance		4,235,000		3,735,000
Protective Life		995,000		640,716
West Coast Bancorp		1,000,000		491,788

	Number of Shares
	09/30/09		12/31/09
Health Care
Beckman Coulter		650,000		450,000
Cephalon		1,250,000		475,000
Cepheid		3,200,000		2,500,000
Charles River Laboratories		1,050,000		700,000
Edwards Lifesciences		600,000		500,000
Henry Schein		1,090,000		800,000
Hologic		1,900,000		0
Human Genome Sciences		3,200,000		2,500,000
InterMune		1,300,000		885,000
Kinetic Concepts		900,000		400,000
Luminex		1,700,000		0
Myriad Genetics		1,735,000		1,200,000
Nektar Therapeutics		4,425,000		3,052,000
Poniard		1,450,916		0
Psychiatric Solutions		2,200,000		1,300,000
Thoratec		148,000		0
United Therapeutics		900,000		760,000
Energy & Minerals
Carrizo Oil & Gas		1,167,000		994,900
Trinidad Drilling (Canada)		5,000,000		3,677,900
XTO Energy		1,580,000		0
Other Industries
American Commercial Lines		625,000		602,000
Forest City Enterprises, Class B		1,158,000		1,105,289
SL Green Realty		580,000		440,000

See accompanying notes to financial statements.

19

Columbia Acorn Fund

Statement of Investments, December 31, 2009

Number of Shares			Value (000)
				Equities: 97.2%
Information 25.8%
		> Business Software 4.7%
	7,000,000	Informatica (a)(b)	$	181,020
		Enterprise Data Integration Software
	2,083,291	ANSYS (a)		90,540
		Simulation Software for Engineers & Designers
	2,050,544	Micros Systems (a)		63,628
		Information Systems for Restaurants & Hotels
	12,500,000	Novell (a)		51,875
		Directory, Operating System & Identity Management Software
	1,200,000	Concur Technologies (a)		51,300
		Web Enabled Cost & Expense Management Software
	800,000	Quality Systems		50,231
		IT Systems for Medical Groups & Ambulatory Care Centers
	1,800,000	Blackbaud		42,534
		Software & Services for Non-profits
	2,425,000	Kenexa (a)(b)		31,646
		Recruiting & Workforce Management Solutions
	1,000,000	Red Hat (a)		30,900
		Maintenance & Support for Open Source & Middleware
	1,134,260	Tyler Technologies (a)		22,583
		Financial, Tax, Court & Document Management Systems for Government
	1,000,000	NetSuite (a)(c)		15,980
		End to End IT Systems Solutions Delivered Over the Web
	3,700,000	Actuate (a)(b)		15,836
		Information Delivery Software & Solutions
	2,594,654	Art Technology Group (a)		11,702
		Software & Tools to Optimize Websites for E-commerce
	1,000,000	Radiant Systems (a)		10,400
		IT Systems for Restaurants, Convenience Stores & Retail Stores
	700,000	Avid Technology (a)		8,932
		Digital Nonlinear Editing Software & Systems
	109,007	Blackboard (a)		4,948
		Education Software
				684,055
		> Computer Hardware & Related Equipment 2.9%
	3,800,000	Amphenol		175,484
		Electronic Connectors
	2,400,000	II-VI (a)(b)		76,320
		Laser Optics & Specialty Materials
	1,140,000	Dolby Laboratories (a)		54,412
		Audio Technology for Consumer Electronics
	1,400,000	Zebra Technologies (a)		39,704
		Bar Code Printers
	800,000	Nice Systems - ADR (Israel) (a)		24,832
		Audio & Video Recording Solutions
	970,000	Netgear (a)		21,039
		Networking Products for Small Business & Home
	740,000	Belden CDT		16,221
		Specialty Cable

Number of Shares			Value (000)
	805,000	Stratasys (a)(c)	$	13,911
		Rapid Prototyping Systems
	340,000	Teradata (a)		10,686
		Enterprise Data Warehouse Systems
				432,609
		> Instrumentation 2.9%
	1,450,000	Mettler Toledo (a)		152,235
		Laboratory Equipment
	5,200,000	Hexagon (Sweden)		76,386
		Measurement Equipment
	2,200,000	FLIR Systems (a)		71,984
		Infrared Cameras
	2,750,000	IPG Photonics (a)(b)		46,035
		Fiber Lasers
	1,545,000	Trimble Navigation (a)		38,934
		GPS-based Instruments
	400,000	Dionex (a)		29,548
		Ion & Liquid Chromatography
	400,000	Hamamatsu Photonics (Japan)		9,661
		Optical Sensors for Medical & Industrial Applications
				424,783
		> Mobile Communications 2.6%
	6,575,000	Crown Castle International (a)		256,688
		Communications Towers
	2,000,000	SBA Communications (a)		68,320
		Communications Towers
	1,200,000	American Tower (a)		51,852
		Communications Towers in USA & Latin America
	1,000,000	MetroPCS Communications (a)		7,630
		Discount Cellular Telephone Services
	1,500,000	Globalstar (a)(c)		1,305
		Satellite Mobile Voice & Data Carrier
				385,795
		> Telephone and Data Services 2.0%
	9,500,000	tw telecom (a)(b)		162,830
		Fiber Optic Telephone/Data Services
	4,200,000	Cogent Communications (a)(b)		41,412
		Internet Data Pipelines
	9,600,000	PAETEC Holding (a)(b)		39,840
		Telephone/Data Services for Business
	600,000	AboveNet (a)		39,024
		Metropolitan Fiber Communications Services
	2,000,000	General Communications (a)		12,760
		Commercial Communications & Consumer CATV, Web & Phone in Alaska
				295,866
		> Financial Processors 1.7%
	2,919,000	Global Payments		157,217
		Credit Card Processor
	10,000,000	Singapore Exchange (Singapore)		58,948
		Singapore Equity & Derivatives Market Operator
	2,125,000	Hong Kong Exchanges and Clearing (Hong Kong)		37,830
		Hong Kong Equity & Derivatives Market Operator
				253,995

See accompanying notes to financial statements.

20

Number of Shares			Value (000)
		> CATV 1.4%
	4,070,000	Discovery Communications, Series C (a)	$	107,936
		CATV Programming
	47,000	Jupiter Telecommunications (Japan)		46,564
		Largest Cable Service Provider in Japan
	1,250,000	Liberty Global, Series A (a)		27,388
		Cable TV Franchises Outside the USA
	4,000,000	Mediacom Communications (a)(b)		17,880
		Cable Television Franchises
				199,768
		> Semiconductors & Related Equipment 1.3%
	3,584,000	ON Semiconductor (a)		31,575
		Mixed-signal & Power Management Semiconductors
	1,035,000	Supertex (a)(b)		30,843
		Analog/Mixed-signal Semiconductors
	1,620,000	Microsemi (a)		28,755
		Analog/Mixed-signal Semiconductors
	870,000	Monolithic Power Systems (a)		20,854
		High Performance Analog & Mixed-signal Integrated Circuits (ICs)
	1,765,000	Pericom Semiconductor (a)(b)		20,350
		Interface Integrated Circuits (ICs) & Frequency Control Products
	3,750,000	Entegris (a)		19,800
		Semiconductor Materials Management Products
	500,000	Littelfuse (a)		16,075
		Little Fuses
	1,900,000	IXYS (a)(b)		14,098
		Power Semiconductors
	2,110,000	Integrated Device Technology (a)		13,652
		Communications Semiconductors
				196,002
		> Telecommunications Equipment 1.2%
	1,045,000	F5 Networks (a)		55,364
		Internet Traffic Management Equipment
	1,534,000	Blue Coat Systems (a)		43,780
		WAN Acceleration & Network Security
	1,580,000	Polycom (a)		39,453
		Video Conferencing Equipment
	1,165,000	CommScope (a)		30,908
		Wireless Infrastructure Equipment & Telecom Cable
				169,505
		> Gaming Equipment & Services 1.1%
	4,025,000	Bally Technologies (a)(b)		166,192
		Slot Machines & Software
				166,192
		> Computer Services 1.0%
	5,000,000	iGate (b)		50,000
		IT & Business Process Outsourcing Services
	1,905,000	SRA International (a)		36,386
		Government IT Services
	1,800,000	Virtusa (a)(b)		16,308
		Offshore IT Outsourcing

Number of Shares			Value (000)
	747,658	ExlService Holdings (a)	$	13,577
		Business Process Outsourcing
	4,500,000	Hackett Group (a)(b)		12,510
		IT Integration & Best Practice Research
	736,499	WNS - ADR (India) (a)		11,084
		Offshore BPO (Business Process Outsourcing) Services
	165,000	ManTech International (a)		7,966
		Government IT Services
				147,831
		> Internet Related 0.7%
	2,500,000	Switch & Data Facilities (a)(b)		50,525
		Network Neutral Data Centers
	188,000	NHN (South Korea) (a)		31,044
		South Korea's Largest Online Search Engine
	800,000	Akamai (a)		20,264
		Content Delivery Network (CDN) for Better Delivery of Online Content
	1,000,000	TheStreet.com		2,400
		Financial Information Websites
				104,233
		> Electronics Distribution 0.6%
	3,125,000	Avnet (a)		94,250
		Electronic Components Distribution
				94,250
		> Business Information & Marketing Services 0.5%
	2,500,000	Navigant Consulting (a)(b)		37,150
		Financial Consulting Firm
	650,000	FTI Consulting (a)		30,654
		Financial Consulting Firm
	1,240,000	InfoGROUP (a)		9,945
		Business Data for Sales Leads
				77,749
		> Contract Manufacturing 0.5%
	1,395,000	Plexus (a)		39,757
		Electronic Manufacturing Services
	3,050,000	Sanmina-SCI (a)		33,642
		Electronic Manufacturing Services
				73,399
		> Advertising 0.2%
	2,700,000	VisionChina Media - ADR (China) (a)		29,484
		Advertising on Digital Screens in China's Mass Transit System
				29,484
		> Satellite Broadcasting & Services 0.2%
	702,000	SES (France)		15,741
		Fixed Satellite Services
	400,000	Eutelsat (France)		12,834
		Fixed Satellite Services
				28,575
		> Consumer Software 0.1%
	3,200,000	THQ (a)		16,128
		Entertainment Software
				16,128

See accompanying notes to financial statements.

21

Columbia Acorn Fund

Statement of Investments, continued

Number of Shares			Value (000)
		> Radio 0.1%
	1,541,000	Salem Communications (a)(b)	$	9,230
		Radio Stations for Religious Programming
	164,991	Saga Communications (a)		2,071
		Radio Stations in Small & Mid-sized Cities
	2,400,000	Spanish Broadcasting System (a)(b)		1,872
		Spanish Language Radio Stations
				13,173
		> TV Broadcasting 0.1%
	2,500,000	Entravision Communications (a)		8,500
		Spanish Language TV & Radio Stations
	1,750,000	Gray Television (a)		2,642
		Mid-market Affiliated TV Stations
				11,142
Information: Total				3,804,534
Consumer Goods & Services 18.2%
		> Retail 6.0%
	4,500,000	Abercrombie & Fitch (b)		156,825
		Teen Apparel Retailer
	4,020,000	Urban Outfitters (a)		140,660
		Apparel & Home Specialty Retailer
	4,200,000	lululemon athletica (a)(b)		126,420
		Premium Active Apparel Retailer
	8,514,272	Chico's FAS (a)		119,626
		Women's Specialty Retailer
	2,564,000	J Crew Group (a)		114,713
		Multi-channel Branded Retailer
	7,500,000	Charming Shoppes (a)(b)		48,525
		Women's Specialty Plus Size Apparel Retailer
	3,500,000	AnnTaylor Stores (a)(b)		47,740
		Women's Apparel Retailer
	6,100,000	Saks (a)(c)		40,016
		Luxury Department Store Retailer
	900,000	Gymboree (a)		39,141
		Children's Apparel Specialty Retailer
	4,250,000	Talbots (a)(b)(c)		37,867
		Women's Specialty Retailer
	1,371,366	Gaiam (a)(b)		10,546
		Healthy Living Catalogs & E-Commerce
	146,390	Rue21 (a)		4,112
		Fashion Value Apparel Retailer
				886,191
		> Travel 2.9%
	4,700,000	Expedia (a)		120,837
		Online Travel Services Company
	1,950,000	Vail Resorts (a)(b)		73,710
		Ski Resort Operator & Developer
	3,700,000	Gaylord Entertainment (a)(b)(c)		73,075
		Convention Hotels
	4,700,000	Avis Budget Group (a)		61,664
		Second Largest Car Rental Company
	1,300,000	Choice Hotels		41,158
		Franchisor of Budget Hotel Brands
	3,000,000	Hertz (a)		35,760
		Largest U.S. Rental Car Operator

Number of Shares			Value (000)
	110,000	Pierre & Vacances (France)	$	8,478
		Vacation Apartment Lets
	141,800	Hyatt Hotels (a)		4,227
		Hotel Owner Operator
				418,909
		> Educational Services 2.5%
	1,350,000	ITT Educational Services (a)		129,546
		Post-secondary Degree Services
	9,500,000	SkillSoft - ADR (a)(b)		99,560
		Web-based Learning Solutions (E-Learning)
	550,000	New Oriental Education & Technology - ADR (China) (a)(c)		41,585
		China's Largest Private Education Service Provider
	1,677,000	Career Education (a)		39,091
		Post-secondary Education
	1,750,301	Universal Technical Institute (a)(b)		35,356
		Vocational Training
	3,000,000	Princeton Review (a)(b)		12,180
		College Preparation Courses
	1,268,258	Cambium Learning Group (a)		4,972
		Education Services for the K-12 Market
	2,000,000	Voyager Learning, Contingent Value Rights (d)		336
		Education Services for the K-12 Market
				362,626
		> Apparel 1.7%
	5,930,000	Coach		216,623
		Designer & Retailer of Branded Leather Accessories
	1,500,000	True Religion Apparel (a)(b)		27,735
		Premium Denim
				244,358
		> Nondurables 1.5%
	1,010,000	Chattem (a)(b)		94,233
		Personal Care Products
	1,700,000	Jarden		52,547
		Branded Household Products
	1,700,000	Helen of Troy (a)(b)		41,582
		Hair Dryers & Curling Irons
	550,000	Energizer Holdings (a)		33,704
		Household & Personal Care Products
				222,066
		> Food & Beverage 0.9%
	1,802,600	Hansen Natural (a)		69,220
		Alternative Beverages
	550,475	Diamond Foods		19,564
		Culinary Ingredients & Snack Foods
	819,000	Flowers Foods		19,459
		Bread & Baked Goods
	3,000,000	Smart Balance (a)		18,000
		Healthy Food Products
	1,153,700	GLG Life Tech (Canada) (a)		8,826
		Produce an All-natural Sweetener Extracted from the Stevia Plant
				135,069

See accompanying notes to financial statements.

22

Number of Shares			Value (000)
		> Furniture & Textiles 0.8%
	2,800,000	Herman Miller (b)	$	44,744
		Office Furniture
	4,000,000	Knoll (b)		41,320
		Office Furniture
	3,000,000	Steelcase		19,080
		Office Furniture
	1,000,000	Interface		8,310
		Modular & Broadloom Carpet
				113,454
		> Other Consumer Services 0.5%
	2,150,000	Lifetime Fitness (a)(b)(c)		53,599
		Sport & Fitness Club Operator
	10,976,800	Lifestyle International (Hong Kong)		20,360
		Mid to High-end Department Store Operator in Hong Kong & China
				73,959
		> Casinos & Gaming 0.4%
	4,050,000	Pinnacle Entertainment (a)(b)		36,369
		Regional Casino Operator
	875,000	Penn National Gaming (a)		23,782
		Regional Casino Operator
				60,151
		> Consumer Goods Distribution 0.3%
	2,100,000	Pool		40,068
		Distributor of Swimming Pool Supplies & Equipment
	264,010	Central European Distribution (Poland) (a)		7,501
		Vodka Production & Spirits Distribution
				47,569
		> Leisure Products 0.3%
	1,390,000	Thor Industries		43,646
		RV & Bus Manufacturer
				43,646
		> Restaurants 0.3%
	650,000	P.F. Chang's China Bistro (a)(c)		24,642
		Mandarin Style Restaurants
	2,000,000	AFC Enterprises (a)(b)		16,320
		Popeye's Restaurants
				40,962
		> Other Entertainment 0.1%
	435,000	CTS Eventim (Germany)		21,237
		Event Ticket Sales
				21,237
		> Other Durable Goods —%
	180,000	Cavco Industries (a)		6,466
		Manufactured Homes
				6,466
Consumer Goods & Services: Total				2,676,663
Industrial Goods & Services 18.1%
		> Machinery 7.6%
	4,200,000	Donaldson (b)		178,668
		Industrial Air Filtration

Number of Shares			Value (000)
	4,500,000	Ametek	$	172,080
		Aerospace/Industrial Instruments
	2,700,000	Oshkosh		99,981
		Specialty Truck Manufacturer
	2,627,500	Clarcor (b)		85,236
		Mobile & Industrial Filters
	2,200,000	ESCO Technologies (b)		78,870
		Automatic Electric Meter Readers
	2,150,000	Pall		77,830
		Filtration & Fluids Clarification
	2,300,000	Pentair		74,290
		Pumps & Water Treatment
	1,100,000	Nordson		67,298
		Dispensing Systems for Adhesives & Coatings
	1,975,000	Mine Safety Appliances (b)		52,396
		Safety Equipment
	1,660,000	MOOG (a)		48,522
		Motion Control Products for Aerospace, Defense & Industrial Markets
	1,300,000	Kaydon		46,488
		Specialized Friction & Motion Control Products
	1,225,000	HEICO (b)		44,051
		FAA Approved Aircraft Replacement Parts
	900,000	Toro		37,629
		Turf Maintenance Equipment
	600,000	Wabtec		24,504
		Freight & Transit Component Supplier
	1,000,000	Jain Irrigation Systems (India)		18,790
		Agricultural Micro-irrigation Systems & Food Processing
	114,000	Neopost (France)		9,419
		Postage Meter Machines
				1,116,052
		> Industrial Materials & Specialty Chemicals 2.9%
	2,000,000	Sociedad Quimica y Minera de Chile - ADR (Chile)		75,140
		Producer of Specialty Fertilizers, Lithium & Iodine
	2,200,000	Nalco Holding Company		56,122
		Provider of Water Treatment & Process Chemicals & Services
	1,530,000	Albemarle		55,646
		Refinery Catalysts & Other Specialty Chemicals
	363,000	Novozymes (Denmark)		37,639
		Industrial Enzymes
	1,600,000	Drew Industries (a)(b)		33,040
		RV & Manufactured Home Components
	500,000	Greif		26,990
		Industrial Packaging
	741,176	Carbone Lorraine (France)		26,720
		Advanced Industrial Materials
	15,000	Sika (Switzerland)		23,335
		Chemicals for Construction & Industrial Applications
	1,000,000	Albany International		22,460
		Paper Machine Clothing & Advanced Textiles
	2,000,000	Kansai Paint (Japan)		16,607
		Paint Producer in Japan, India, China & Southeast Asia

See accompanying notes to financial statements.

23

Columbia Acorn Fund

Statement of Investments, continued

Number of Shares			Value (000)
		> Industrial Materials & Specialty Chemicals—continued
	600,000	Crown Holdings (a)	$	15,348
		Metal Can Packaging
	450,000	Celanese		14,445
		Commodity & Specialty Chemicals Provider
	200,000	Silgan Holdings		11,576
		Metal & Plastic Packaging
	350,000	Koppers Holdings		10,654
		Integrated Provider of Carbon Compounds
				425,722
		> Industrial Distribution 2.0%
	2,555,200	Airgas		121,628
		Industrial Gas Distributor
	1,000,000	WW Grainger		96,830
		Industrial Distribution
	2,600,000	Interline Brands (a)(b)		44,902
		Industrial Distribution
	625,000	Watsco		30,612
		HVAC Distribution
				293,972
		> Other Industrial Services 1.8%
	3,300,000	Expeditors International of Washington		114,609
		International Freight Forwarder
	1,500,000	Imtech (Netherlands)		40,253
		Electromechanical & ICT Installation & Maintenance
	1,300,000	Forward Air		32,565
		Freight Transportation Between Airports
	2,000,000	UTI Worldwide		28,640
		Freight Forwarding & Logistics
	1,750,000	Mobile Mini (a)		24,658
		Portable Storage Units Leasing
	924,900	TrueBlue (a)		13,698
		Temporary Manual Labor
	900,000	American Reprographics (a)		6,309
		Document Management & Logistics
				260,732
		> Outsourcing Services 1.2%
	35,000,000	Olam International (Singapore)		65,547
		Agriculture Supply Chain Manager
	2,070,000	Quanta Services (a)		43,139
		Electrical & Telecom Construction Services
	1,428,224	Administaff (b)		33,692
		Professional Employer Organization
	3,000,000	Serco (United Kingdom)		25,505
		Facilities Management
	600,000	GP Strategies (a)		4,518
		Training Programs
				172,401
		> Construction 1.0%
	700,000	Martin Marietta Materials		62,587
		Aggregates
	60,000	NVR (a)		42,642
		D.C. Homebuilder
	850,000	Simpson Manufacturing		22,856
		Wall Joint Maker

Number of Shares			Value (000)
	687,500	Ritchie Brothers Auctioneers (c)	$	15,421
		Heavy Equipment Auctioneer
	384,000	M/I Homes (a)		3,990
		Columbus-based Home Builder
				147,496
		> Waste Management 0.6%
	1,858,500	Republic Services		52,614
		Solid Waste Management
	1,200,000	Waste Connections (a)		40,008
		Solid Waste Management
				92,622
		> Electrical Components 0.4%
	1,300,000	Acuity Brands		46,332
		Commercial Lighting Fixtures
	1,000,000	Ushio (Japan)		16,648
		Industrial Light Sources
				62,980
		> Conglomerates 0.3%
	2,200,000	Aalberts Industries (Netherlands)		31,431
		Flow Control & Heat Treatment
	600,000	Ibiden (Japan)		21,368
		Electronic Parts & Ceramics
				52,799
		> Steel 0.2%
	1,680,000	GrafTech International (a)		26,124
		Industrial Graphite Materials Producer
				26,124
		> Water 0.1%
	1,750,000	Mueller Water Products		9,100
		Fire Hydrants, Valves & Ductile Iron Pipes
				9,100
Industrial Goods & Services: Total				2,660,000
Finance 11.8%
		> Banks 3.7%
	2,689,000	BOK Financial		127,781
		Tulsa-based Southwest Bank
	5,718,205	Valley National Bancorp (c)		80,798
		New Jersey/New York Bank
	4,150,000	TCF Financial		56,523
		Great Lakes Bank
	1,172,396	SVB Financial Group (a)		48,877
		Bank to Venture Capitalists
	2,305,600	MB Financial		45,467
		Chicago Bank
	3,737,900	Associated Banc-Corp (c)		41,154
		Midwest Bank
	640,000	Cullen/Frost Bankers		32,000
		Texas Bank
	2,440,000	Wilmington Trust		30,110
		Delaware Trust Bank
	1,200,000	TriCo Bancshares (b)		19,980
		California Central Valley Bank
	660,000	Hudson Valley		16,276
		Metro New York City Bank

See accompanying notes to financial statements.

24

Number of Shares			Value (000)
		> Banks—continued
	295,000	City National	$	13,452
		Bank & Asset Manager
	830,700	CVB Financial (c)		7,177
		Inland Empire Business Bank
	1,170,000	First Busey		4,551
		Illinois Bank
	500,000	Sandy Spring Bancorp (c)		4,445
		Baltimore, D.C. Bank
	246,505	Pacific Continental		2,820
		Pacific N.W. Bank
	251,000	Eagle Bancorp (a)		2,628
		Metro D.C. Bank
	583,872	Green Bankshares (c)		2,073
		Tennessee Bank
	491,788	West Coast Bancorp		1,033
		Portland Community Bank
				537,145
		> Insurance 2.9%
	2,427,400	Leucadia National (a)		57,748
		Insurance Holding Company
	1,890,000	HCC Insurance Holdings		52,863
		Specialty Insurance
	9,420,000	Conseco (a)		47,100
		Life, Long-term Care & Medical Supplement Insurance
	849,000	Hanover Insurance Group		37,721
		Personal & Commercial Lines Insurance
	1,200,000	Assurant		35,376
		Specialty Insurance
	100,000	Markel (a)		34,000
		Specialty Insurance
	1,450,000	Delphi Financial Group		32,437
		Workers Compensation & Group Employee Benefit Products & Services
	575,000	Navigators Group (a)		27,088
		Specialty Insurance
	1,000,000	Aspen Insurance		25,450
		Commercial Lines Insurance/Reinsurance
	1,420,000	Selective Insurance Group		23,359
		Commercial & Personal Lines Insurance
	832,000	Willis Group (Ireland)		21,948
		Insurance Broker
	900,000	Tower Group		21,069
		Commercial & Personal Lines Insurance
	640,716	Protective Life		10,604
		Life Insurance
				426,763
		> Finance Companies 2.5%
	7,235,000	AmeriCredit (a)(b)		137,754
		Auto Lending
	1,545,000	World Acceptance (a)(b)		55,357
		Personal Loans
	2,350,000	McGrath Rentcorp (b)		52,546
		Temporary Space & IT Rentals
	1,730,000	GATX		49,737
		Rail Car Lessor
	3,300,000	H&E Equipment Services (a)(b)		34,617
		Heavy Equipment Leasing

Number of Shares			Value (000)
	655,000	Aaron's (c)	$	18,163
		Rent to Own
	1,650,000	CAI International (a)(b)		14,900
		International Container Leasing
	1,091,000	Marlin Business Services (a)(b)		8,652
		Small Equipment Leasing
				371,726
		> Brokerage & Money Management 1.6%
	3,735,000	Eaton Vance		113,581
		Specialty Mutual Funds
	6,448,000	SEI Investments		112,969
		Mutual Fund Administration & Investment Management
	700,000	Investment Technology Group (a)		13,790
		Electronic Trading
				240,340
		> Savings & Loans 1.1%
	6,480,000	People's United		108,216
		Connecticut Savings & Loan
	450,000	Housing Development Finance (India)		25,935
		Indian Mortgage Lender
	731,478	ViewPoint Financial		10,541
		Texas Thrift
	1,010,000	Provident New York Bancorp		8,524
		New York State Thrift
	234,693	Berkshire Hills Bancorp		4,854
		Northeast Thrift
				158,070
Finance: Total				1,734,044
Health Care 9.6%
		> Medical Equipment & Devices 3.1%
	3,000,000	Alexion Pharmaceuticals (a)		146,460
		Biotech Focused on Orphan Diseases
	1,700,000	Illumina (a)(c)		52,105
		Leading Tools & Service Provider for Genetic Analysis
	2,400,000	American Medical Systems (a)		46,296
		Medical Devices to Treat Urological Conditions
	500,000	Edwards Lifesciences (a)		43,425
		Heart Valves
	700,000	Haemonetics (a)		38,605
		Blood & Plasma Collection Equipment
	1,000,000	Orthofix International (a)(b)		30,970
		Bone Fixation & Stimulation Devices
	450,000	Beckman Coulter		29,448
		In-vitro Clinical Diagnostics
	850,000	Sirona Dental Systems (a)		26,979
		Manufacturer of Dental Equipment
	568,910	Gen-Probe (a)		24,406
		Molecular In-vitro Diagnostics
	400,000	Kinetic Concepts (a)		15,060
		Wound Healing & Tissue Repair Products

See accompanying notes to financial statements.

25

Columbia Acorn Fund

Statement of Investments, continued

Number of Shares			Value (000)
		> Medical Equipment & Devices—continued
	1,232,900	Nanosphere (a)	$	7,940
		Molecular Diagnostics Company with Best of Breed Platform
				461,694
		> Biotechnology & Drug Delivery 3.0%
	2,500,000	Human Genome Sciences (a)		76,500
		Biotech Focused on HCV, Inflammation & Cancer
	3,250,000	BioMarin (a)		61,132
		Biotech Focused on Orphan Diseases
	4,117,700	Seattle Genetics (a)		41,836
		Antibody-based Therapies for Cancer
	1,350,000	Auxilium Pharmaceuticals (a)		40,473
		Biotech Focused on Niche Disease Areas
	760,000	United Therapeutics (a)		40,014
		Biotech Focused on Rare Diseases
	1,300,000	Acorda Therapeutics (a)		32,786
		Biopharma Company Focused on Nervous Disorder Drugs
	1,200,000	Myriad Genetics (a)		31,320
		Genetic Diagnostics
	3,052,000	Nektar Therapeutics (a)		28,445
		Drug Delivery Technologies
	600,000	AMAG Pharmaceuticals (a)		22,818
		Biotech Focused on Niche Diseases
	2,800,000	Allos Therapeutics (a)(c)		18,396
		Cancer Drug Development
	475,000	Onyx Pharmaceuticals (a)		13,937
		Commercial-stage Biotech Focused on Cancer
	885,000	InterMune (a)		11,540
		Drugs for Pulmonary Fibrosis & Hepatitis C
	1,400,000	Micromet (a)(c)		9,324
		Next-generation Antibody Technology
	2,700,000	NPS Pharmaceuticals (a)(b)		9,180
		Orphan Drugs & Healthy Royalties
	359,944	MicroDose Technologies (a)(d)		162
		Drug Inhaler Development
	187,500	Locus Pharmaceuticals, Series A-1, Pfd. (a)(d)		9
	96,644	Locus Pharmaceuticals, Series B-1, Pfd. (a)(d)		5
		High Throughput Rational Drug Design
				437,877
		> Medical Supplies 1.7%
	800,000	Henry Schein (a)		42,080
		Largest Distributor of Healthcare Products
	1,675,000	QIAGEN (Netherlands) (a)(c)		37,386
		Life Science Tools & Molecular Diagnostics
	665,000	Idexx Laboratories (a)(c)		35,538
		Diagnostic Equipment & Services for Veterinarians
	486,000	Techne		33,320
		Cytokines, Antibodies & Other Reagents for Life Science

Number of Shares			Value (000)
	2,500,000	Cepheid (a)	$	31,200
		Molecular Diagnostics
	850,000	ICU Medical (a)(b)		30,974
		Intravenous Therapy Products
	1,400,000	Immucor (a)		28,336
		Automated Blood Typing Reagents
	150,000	Owens & Minor		6,440
		Distribution of Medical Supplies
				245,274
		> Health Care Services 1.6%
	2,750,000	PSS World Medical (a)		62,067
		Distributor of Medical Supplies
	700,000	Mednax (a)		42,077
		Physician Management for Pediatric & Anesthesia Practices
	1,300,000	Psychiatric Solutions (a)		27,482
		Behavioral Health Services
	4,250,000	eResearch Technology (a)(b)		25,543
		Clinical Research Services
	700,000	Charles River Laboratories (a)		23,583
		Pharmaceutical Research
	850,000	Healthcare Services Group		18,241
		Outsourced Services to Long-term Care Industry
	700,000	Allscripts-Misys Healthcare (a)		14,161
		Clinical IT Solutions for Physician Offices
	800,000	Emdeon (a)		12,200
		Revenue & Payment Cycle Management
	250,000	AthenaHealth (a)		11,310
		Revenue Cycle Management for Physician Offices
				236,664
		> Pharmaceuticals 0.2%
	475,000	Cephalon (a)		29,645
		Specialty Pharmaceuticals for Pain, Central Nervous System & Oncology
	2,450,000	United Drug (Ireland)		7,475
		Irish Pharmaceutical Wholesaler & Outsourcer
				37,120
Health Care: Total				1,418,629
Energy & Minerals 9.3%
		> Oil Services 4.3%
	3,100,000	FMC Technologies (a)		179,304
		Oil & Gas Wellhead Manufacturer
	2,809,568	Fugro (Netherlands)		160,446
		Sub-sea Oilfield Services
	3,200,000	Atwood Oceanics (a)		114,720
		Offshore Drilling Contractor
	1,000,000	Oceaneering International (a)		58,520
		Provider of Sub-sea Services & Manufactured Products
	1,670,000	ShawCor (Canada)		46,866
		Oil & Gas Pipeline Products
	3,677,900	Trinidad Drilling (Canada)		24,863
		Operator of Deep Land Drilling Rigs & Service Rigs Throughout North America

See accompanying notes to financial statements.

26

Number of Shares			Value (000)
		> Oil Services—continued
	1,750,000	Tesco (a)	$	22,592
		Developing New Well Drilling Technologies
	375,000	Bristow (a)		14,419
		Largest Provider of Helicopter Services to Offshore Oil & Gas Producers
	600,000	Tetra Technologies (a)		6,648
		U.S.-based Services Company with Life of Field Approach
	2,983,500	Horizon North Logistics (Canada) (a)		4,707
		Provides Diversified Oil Service Offering in Northern Canada
				633,085
		> Oil & Gas Producers 3.6%
	3,200,000	Southwestern Energy (a)		154,240
		Oil & Gas Producer
	4,910,550	Pacific Rubiales Energy (Canada) (a)		72,542
		Oil Production & Exploration in Colombia
	1,100,000	Range Resources		54,835
		Oil & Gas Producer
	2,400,000	Tullow Oil (United Kingdom)		50,049
		Oil & Gas Producer
	975,000	Ultra Petroleum (a)		48,614
		Oil & Gas Producer
	2,700,000	Denbury Resources (a)		39,960
		Oil Producer Using Co2 Injection
	994,900	Carrizo Oil & Gas (a)		26,355
		Oil & Gas Producer
	4,000,000	Gran Tierra Energy (Canada) (a)		22,948
		Oil Exploration & Production in Colombia, Peru & Argentina
	24,000,000	Cap-Link Ventures (a)(d)		10,097
	24,000,000	Cap-Link Ventures-Warrants (a)(d)		6,425
		Oil & Gas Exploration & Production in Colombia, Peru & Paraguay
	250,000	Cabot Oil & Gas		10,898
		Large Natural Gas Producer in Appalachia & Gulf Coast
	347,600	Baytex (Canada)		9,871
		Oil & Gas Producer in Canada
	1,198,100	Pan Orient (Canada) (a)		8,706
		Growth Oriented & Return Focused Asian Explorer
	1,200,000	Houston American Energy		7,392
		Oil & Gas Exploration/Production in Colombia
	1,500,000	Vaalco Energy		6,825
		Oil & Gas Producer
	8,435,000	Alange Energy (Colombia) (a)		5,081
		Oil & Gas Exploration/Production in Colombia
	264,000	Petrolifera Petroleum (a)		245
		Oil & Gas Exploration & Production in South America
				535,083
		> Mining 1.1%
	2,520,000	Silver Wheaton (Canada) (a)		37,850
		Silver Mining Royalty Company
	290,000	Core Laboratories (Netherlands)		34,255
		Oil & Gas Reservoir Consulting
	500,000	Royal Gold		23,550
		Precious Metals Mining Royalty Company

Number of Shares			Value (000)
	7,725,000	Uranium One (South Africa) (a)	$	22,307
		Uranium Mines in Kazakhstan, the U.S. & Australia
	1,000,000	Ivanhoe Mines (Canada) (a)		14,830
		Copper Mine Project in Mongolia
	6,333,700	Zhaojin Mining Industry (China)		12,493
		Gold Mining & Refining in China
	10,000,000	Orko Silver (Canada) (a)(b)		11,474
		Silver Exploration & Development
	1,500,000	PolyMet Mining (a)(c)		4,590
		Copper & Nickel Miner
				161,349
		> Independent Power 0.1%
	340,000	Wisconsin Energy		16,942
		Wisconsin Utility
				16,942
		> Oil Refining, Marketing & Distribution 0.1%
	175,000	Vopak (Netherlands)		13,826
		World's Largest Operator of Petroleum & Chemical Storage Terminals
				13,826
		> Alternative Energy 0.1%
	400,000	STR Holdings (a)		6,284
		Makes Encapsulant for Solar Power Modules/Provides Quality Assurance
	1,800,000	Synthesis Energy Systems (China) (a)		1,670
		Owner/Operator of Gasification Plants
				7,954
Energy & Minerals: Total				1,368,239
Other Industries 4.4%
		> Real Estate 2.6%
	675,000	Federal Realty Investment Trust		45,711
		Shopping Centers
	850,000	Digital Realty Trust		42,738
		Technology-focused Office Buildings
	2,260,902	BioMed Realty Trust		35,677
		Life Science-focused Office Buildings
	22,000,000	Ascendas REIT (Singapore)		34,453
		Singapore Industrial Property Landlord
	900,000	Corporate Office Properties		32,967
		Office Buildings
	880,376	Macerich (c)		31,649
		Regional Shopping Malls
	900,000	American Campus Communities		25,290
		Student Housing
	40,000,000	Mapletree Logistics Trust (Singapore)		22,290
		Asian Logistics Landlord
	440,000	SL Green Realty		22,106
		Manhattan Office Buildings
	700,000	Washington REIT		19,285
		Washington D.C. Diversified Properties
	3,750,000	DCT Industrial Trust		18,825
		Industrial Properties
	1,400,000	Extra Space Storage		16,170
		Self Storage Facilities

See accompanying notes to financial statements.

27

Columbia Acorn Fund

Statement of Investments, continued

Number of Shares			Value (000)
		> Real Estate—continued
	2,800	Orix JREIT (Japan)	$	13,916
		Diversified REIT
	1,105,289	Forest City Enterprises, Class B (a)		13,131
		Commercial & Residential Property Developer
	2,300,000	Kite Realty Group		9,361
		Community Shopping Centers
	37,407	Security Capital European Realty (Luxembourg) (a)(d)(e)		—
		Self Storage Properties
				383,569
		> Transportation 1.1%
	2,110,000	JB Hunt Transport Services		68,090
		Truck & Intermodal Carrier
	2,480,000	Heartland Express		37,869
		Regional Trucker
	2,500,000	Rush Enterprises, Class A (a)(b)		29,725
	500,000	Rush Enterprises, Class B (a)(b)		5,250
		Truck Sales & Services
	500,000	World Fuel Services		13,395
		Global Fuel Broker
	602,000	American Commercial Lines (a)		11,035
		Operator of Inland Barges/Builder of Barges & Vessels
	150,000	Old Dominion Freight Lines (a)		4,605
		LTL Trucker
				169,969
		> Regulated Utilities 0.7%
	2,200,000	Northeast Utilities		56,738
		Regulated Electric Utility
	500,000	Red Electrica de Espana (Spain)		27,711
		Spanish Power Transmission
	3,500,000	Terna (Italy)		15,060
		Italian Power Transmission
				99,509
Other Industries: Total				653,047
Total Equities: 97.2% (Cost: $10,369,467)				14,315,156
Securities Lending Collateral: 1.3%
	183,433,582	Dreyfus Government Cash Management Fund (f) (7 day yield of 0.000%)		183,434
Total Securities Lending Collateral: (Cost: $183,434)				183,434

Principal Amount (000)			Value (000)
Short-Term Obligations: 3.1%
		> Repurchase Agreement 2.8%
$	413,094	Repurchase Agreement with Fixed Income Clearing Corp., dated 12/31/09, due 1/04/10 at 0.00%, collateralized by U.S. Government Agency obligations with various maturities to 9/17/10, market value $421,361 (repurchase proceeds $413,094)	$	413,094
				413,094
		> Commercial Paper 0.3%
	50,000	Toyota Motor Credit 0.16% due 1/04/10		49,999
				49,999
Total Short-Term Obligations: (Amortized Cost: $463,093)				463,093
Total Investments: 101.6% (Cost: $11,015,994)(g)(h)				14,961,683
Obligation to Return Collateral for Securities Loaned: (1.3)%				(183,434	)
Cash and Other Assets Less Liabilities: (0.3)%				(51,098	)
Total Net Assets: 100.0%			$	14,727,151

ADR = American Depositary Receipts

See accompanying notes to financial statements.

28

> Notes to Statement of Investments (dollar values in thousands)

(a)  Non-income producing security.

(b)  An affiliated person of the Fund may include any company in which the Fund owns five percent or more of its outstanding voting shares. Holdings and transactions in these affiliated companies during the twelve months ended December 31, 2009, are as follows:

Affiliates	Balance of Shares Held 12/31/08		Purchases/ Additions		Sales/ Reductions		Balance of Shares Held 12/31/09		Value		Dividend
Abercrombie & Fitch		1,925,000		2,695,000		120,000		4,500,000	$	156,825	$	2,124
Actuate		1,683,760		2,016,240		-		3,700,000		15,836		-
Administaff		2,025,000		-		596,776		1,428,224		33,692		1,014
AFC Enterprises		1,800,000		200,000		-		2,000,000		16,320		-
AmeriCredit		7,235,000		-		-		7,235,000		137,754		-
AnnTaylor Stores		-		3,500,000		-		3,500,000		47,740		-
Array Biopharma*		2,910,000		-		2,910,000		-		-		-
Avis Budget Group*		-		6,000,000		1,300,000		4,700,000		61,664		-
Bally Technologies		3,750,000		275,000		-		4,025,000		166,192		-
CAI International		1,500,000		150,000		-		1,650,000		14,900		-
Carrizo Oil & Gas*		2,525,000		200,000		1,730,100		994,900		26,355		-
Cepheid*		3,100,000		900,000		1,500,000		2,500,000		31,200		-
Champion Enterprises*		4,500,000		-		4,500,000		-		-		-
Charlotte Russe*		-		1,900,000		1,900,000		-		-		-
Charming Shoppes		-		7,500,000		-		7,500,000		48,525		-
Chattem		1,010,000		-		-		1,010,000		94,233		-
Clarcor		3,000,000		-		372,500		2,627,500		85,236		1,103
Cogent Communications		4,300,000		-		100,000		4,200,000		41,412		-
Conseco*		9,420,000		-		-		9,420,000		47,100		-
Donaldson		4,200,000		-		-		4,200,000		178,668		1,932
Drew Industries		1,324,000		276,000		-		1,600,000		33,040		-
Entravision Communications*		2,500,000		-		-		2,500,000		8,500		-
eResearch Technology		3,935,901		314,099		-		4,250,000		25,543		-
ESCO Technologies		2,200,000		-		-		2,200,000		78,870		-
FARO Technologies*		1,275,000		-		1,275,000		-		-		-
Forest City Enterprises, Class B*		1,158,000		-		52,711		1,105,289		13,131		-
Forward Air*		1,900,000		-		600,000		1,300,000		32,565		413
Gaiam		1,200,000		171,366		-		1,371,366		10,546		-
Gaylord Entertainment		3,300,000		400,000		-		3,700,000		73,075		-
H&E Equipment Services		3,300,000		-		-		3,300,000		34,617		-
Hackett Group		4,600,000		-		100,000		4,500,000		12,510		-
HEICO		850,000		375,000		-		1,225,000		44,051		125
Helen of Troy		1,900,000		-		200,000		1,700,000		41,582		-
Herman Miller		3,000,000		500,000		700,000		2,800,000		44,744		682
Hot Topic*		-		3,791,890		3,791,890		-		-		-
ICU Medical		1,250,000		-		400,000		850,000		30,974		-
iGate		5,000,000		-		-		5,000,000		50,000		550
II-VI		2,400,000		-		-		2,400,000		76,320		-
Informatica		5,500,000		1,500,000		-		7,000,000		181,020		-
Interline Brands		2,000,000		600,000		-		2,600,000		44,902		-
IPG Photonics		2,750,000		-		-		2,750,000		46,035		-
ITT Educational Services*		2,150,000		-		800,000		1,350,000		129,546		-
IXYS		2,035,000		400,000		535,000		1,900,000		14,098		-
Kenexa		2,425,000		-		-		2,425,000		31,646		-
Kite Realty Group*		1,900,000		400,000		-		2,300,000		9,361		1,016
Knoll		3,300,000		700,000		-		4,000,000		41,320		636
Lifetime Fitness		1,900,000		250,000		-		2,150,000		53,599		-
lululemon athletica		-		4,200,000		-		4,200,000		126,420		-
Luminex*		1,110,000		1,343,000		2,453,000		-		-		-
Marlin Business Services		1,091,000		-		-		1,091,000		8,652		-
MB Financial*		2,020,000		285,600		-		2,305,600		45,467		306
McGrath Rentcorp		1,890,000		460,000		-		2,350,000		52,546		1,872
Mediacom Communications		4,000,000		344,085		344,085		4,000,000		17,880		-
Mine Safety Appliances		1,975,000		-		-		1,975,000		52,396		1,896
Mobile Mini*		1,750,000		-		-		1,750,000		24,658		-
Navigant Consulting		2,500,000		-		-		2,500,000		37,150		-
Nektar Therapeutics*		5,325,000		-		2,273,000		3,052,000		28,445		-
NPS Pharmaceuticals		-		2,700,000		-		2,700,000		9,180		-

See accompanying notes to financial statements.

29

Columbia Acorn Fund

Statement of Investments, continued

> Notes to Statement of Investments (dollar values in thousands)

Affiliates	Balance of Shares Held 12/31/08		Purchases/ Additions		Sales/ Reductions		Balance of Shares Held 12/31/09		Value		Dividend
Orko Silver		-		10,000,000		-		10,000,000	$	11,474	$	-
Orthofix International		600,000		400,000		-		1,000,000		30,970		-
PAETEC Holding		8,000,000		1,600,000		-		9,600,000		39,840		-
Pericom Semiconductor		915,000		850,000		-		1,765,000		20,350		-
Pinnacle Entertainment		4,050,000		-		-		4,050,000		36,369		-
Pool*		2,600,000		-		500,000		2,100,000		40,068		1,287
Princeton Review		2,550,000		450,000		-		3,000,000		12,180		-
Quality Systems*		1,850,000		-		1,050,000		800,000		50,232		1,665
Radiant Systems*		3,050,000		-		2,050,000		1,000,000		10,400		-
Rush Enterprises		2,750,000		250,000		-		3,000,000		34,975		-
Salem Communications		1,541,000		-		-		1,541,000		9,230		-
Savient Pharmaceuticals*		1,416,941		1,583,059		3,000,000		-		-		-
SeaBright Insurance Holdings*		1,200,000		-		1,200,000		-		-		-
Seattle Genetics*		4,400,000		867,700		1,150,000		4,117,700		41,836		-
SkillSoft - ADR		9,500,000		-		-		9,500,000		99,560		-
Smart Balance*		5,000,000		500,000		2,500,000		3,000,000		18,000		-
Spanish Broadcasting System		2,400,000		-		-		2,400,000		1,872		-
Stewart Information Services*		909,420		-		909,420		-		-		-
Stratasys*		1,180,000		-		375,000		805,000		13,911		-
Supertex		1,035,000		-		-		1,035,000		30,843		-
Switch & Data Facilities		2,500,000		-		-		2,500,000		50,525		-
Talbots		4,250,000		-		-		4,250,000		37,867		-
TriCo Bancshares		1,200,000		-		-		1,200,000		19,980		624
True Religion Apparel		1,150,000		633,000		283,000		1,500,000		27,735		-
tw telecom		9,500,000		-		-		9,500,000		162,830		-
Universal Technical Institute		1,500,000		250,301		-		1,750,301		35,356		-
Vail Resorts		2,390,000		-		440,000		1,950,000		73,710		-
Viad*		1,032,075		-		1,032,075		-		-		73
Virtusa		1,000,000		800,000		-		1,800,000		16,308		-
Voyager Learning*		2,000,000		-		2,000,000		-		-		-
West Coast Bancorp*		837,000		163,000		508,212		491,788		1,033		28
World Acceptance		1,545,000		-		-		1,545,000		55,357		-
Total of Affiliated Transactions		225,449,097		62,694,340		45,551,769		242,591,668	$	3,750,852	$	17,346

*  At December 31, 2009, the Fund owned less than five percent of the company's outstanding voting shares.

  The aggregate cost and value of these companies at December 31, 2009, were $3,167,879 and $3,750,852, respectively. Investments in affiliated companies represented 25.5% of the Fund's total net assets at December 31, 2009.

(c)  All or a portion of this security was on loan at December 31, 2009. The total market value of Fund securities on loan at December 31, 2009 was $175,896.

(d)  Denotes a restricted security, which is subject to restrictions on resale under federal securities laws. These securities are valued at a fair value determined in good faith under consistently applied procedures established by the Board of Trustees. At December 31, 2009, the market value of these securities amounted to $17,034, which represented 0.12% of total net assets.

  Additional information on these securities is as follows:

Security	Acquisition Dates	Shares		Cost		Value
Cap-Link Ventures	11/20/09		24,000,000	$	4,898	$	10,097
Cap-Link Ventures-Warrants	11/20/09		24,000,000		3,117		6,425
Voyager Learning, Contingent Value Rights	12/24/09		2,000,000		-		336
MicroDose Technologies	11/24/00		359,944		2,005		162
Locus Pharmaceuticals, Series A-1, Pfd.	9/05/01		187,500		7,500		9
Locus Pharmaceuticals, Series B-1, Pfd.	2/08/07		96,644		280		5
Security Capital European Realty	8/20/98-7/20/99		37,407		205		-
				$	18,005	$	17,034

(e)  Security has no value.

(f)  Investment made with cash collateral received from securities lending activity.

(g)  At December 31, 2009, for federal income tax purposes, the cost of investments was $11,076,313 and net unrealized appreciation was $3,885,370, consisting of gross unrealized appreciation of $5,220,362 and gross unrealized depreciation of $1,334,992.

See accompanying notes to financial statements.

30

> Notes to Statement of Investments (dollar values in thousands)

(h)  On December 31, 2009, the market value of foreign securities represented 11.08% of total net assets. The Fund's foreign portfolio was diversified as follows:

	Value		Percentage of Net Assets
Netherlands	$	317,597		2.16
Canada		263,483		1.79
Singapore		181,238		1.23
Japan		124,764		0.85
China		85,232		0.58
Sweden		76,386		0.52
United Kingdom		75,554		0.51
Chile		75,140		0.51
France		73,192		0.5
Hong Kong		58,190		0.39
India		55,809		0.38
	Value		Percentage of Net Assets
South Korea	$	53,351		0.36
Denmark		37,639		0.26
Ireland		29,423		0.20
Spain		27,711		0.19
Israel		24,832		0.17
Switzerland		23,335		0.16
Germany		21,237		0.14
Italy		15,060		0.1
Poland		7,501		0.05
Colombia		5,081		0.03
Luxembourg		-		-
Total Foreign Portfolio	$	1,631,755		11.08

The following table summarizes the inputs used, as of December 31, 2009, in valuing the Fund's assets:

Investment Type	Quoted Prices (Level 1)		Other Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Equities
Information	$	3,515,526	$	289,008	$	-	$	3,804,534
Consumer Goods & Services		2,626,252		50,075		336		2,676,663
Industrial Goods & Services		2,326,738		333,262		-		2,660,000
Finance		1,708,109		25,935		-		1,734,044
Health Care		1,410,978		7,475		176		1,418,629
Energy & Minerals		1,114,903		253,336		-		1,368,239
Other Industries		539,617		113,430		-		653,047
Total Equities		13,242,123		1,072,521		512		14,315,156
Total Securities Lending Collateral		183,434		-		-		183,434
Total Short-Term Obligations		-		463,093		-		463,093
Total Investments	$	13,425,557	$	1,535,614	$	512	$	14,961,683

  The Fund's assets assigned to the Level 2 input category include certain foreign securities for which a third party statistical pricing service may be employed for purposes of fair market valuation.

  The following table reconciles asset balances for the twelve-month period ending December 31, 2009, in which significant unobservable inputs (Level 3) were used in determining value:

Investments in Securities	Balance as of December 31, 2008		Accrued Discounts/ Premiums		Realized Gain/(Loss)			Change in Unrealized Appreciation (Depreciation)		Net Purchases (Sales)		Net Transfers into (out of) Level 3		Balance as of December 31, 2009
Equities
Consumer Goods & Services	$	-	$	-	$	-		$	-	$	-	$	336	$	336
Health Care		426		-		(4,500	)		4,250		-		-		176
	$	426	$	-	$	(4,500	)	$	4,250	$	-	$	336	$	512

  The information in the above reconciliation table represents fiscal year to date activity for any securities identified as using Level 3 inputs during the current fiscal period.

  The change in unrealized appreciation (depreciation) attributed to securities owned at December 31, 2009, which were valued using significant unobservable inputs (Level 3) amounted to $4,250. This amount is included in net change in unrealized appreciation on the Statements of Changes in Net Assets.

  For more information on valuation inputs, and their aggregation into the levels used in the tables above, please refer to the Security Valuation section in the accompanying Notes to Financial Statements.

See accompanying notes to financial statements.

31

Columbia Acorn International

Major Portfolio Changes in the Fourth Quarter (Unaudited)

	Number of Shares
	09/30/09		12/31/09
Purchases
Asia
> Japan
Icom		213,700		312,000
Makita		430,000		590,000
Torishima Pump Manufacturing		339,100		633,800
> China
China Communication Services		0		24,952,000
Shandong Weigao		5,018,500		6,000,000
Sino Ocean Land		0		15,782,000
Zhaojin Mining Industry		0		11,764,400
> India
Jain Irrigation Systems		1,868,376		2,000,000
Patel Engineering		878,824		1,271,000
> Taiwan
Everlight Electronics		8,704,793		9,297,575
Simplo Technology		4,020,500		5,693,500
Yuanta Financial Holdings		45,000,000		55,734,000
Europe
> United Kingdom
Chemring		400,000		580,000
Cobham		4,950,000		6,800,000
N Brown Group		3,150,000		3,465,000
Schroders		1,350,000		1,466,000
Serco		6,100,000		6,500,000
Spice Group		0		4,722,884
> Netherlands
Smit Internationale		244,969		339,146
Vopak		474,600		520,100
> France
Eutelsat		437,000		583,000
Hi-Media		730,000		966,229
Saft		469,574		506,362
Zodiac Aerospace		411,000		541,000
> Germany
Elringklinger		696,311		750,000
Tognum		790,000		960,000
Vossloh		200,000		245,000
Wirecard		0		1,180,000
> Switzerland
Bank Sarasin & Cie		126,406		349,882
> Sweden
East Capital Explorer		750,000		982,742
Sweco		3,235,000		3,887,000
> Italy
Ansaldo STS		0		1,029,000
CIR		9,610,356		11,180,000

	Number of Shares
	09/30/09		12/31/09
Credito Emiliano		2,639,000		3,069,000
Terna		0		5,246,000
> Ireland
Paddy Power		300,300		448,000
> Spain
Red Electrica de Espana		532,000		573,000
> Greece
Intralot		3,427,000		3,725,000
> Portugal
Redes Energéticas Nacionais		0		3,909,580
> Iceland
Marel		22,568,604		29,868,604
Other Countries
> Canada
Baytex		0		432,900
Pan Orient		517,100		1,480,610
> United States
Bristow		300,000		391,000
> Australia
Australian Stock Exchange		550,000		700,000
SAI Global		0		460,092
Seek		0		731,000
United Group		965,000		2,068,000

See accompanying notes to financial statements.

32

	Number of Shares
	09/30/09		12/31/09
Sales
Asia
> Japan
Aeon Mall		1,146,300		955,500
Asics		2,143,500		1,905,500
Benesse		398,900		306,900
Point		519,570		478,570
Unicharm PetCare		390,300		336,300
> China
China Shipping Development		7,891,000		0
RexLot Holdings		250,000,000		240,000,000
> Singapore
Mapletree Logistics Trust		77,000,000		70,000,000
> Taiwan
President Chain Store		11,353,184		0
> Hong Kong
Hong Kong Exchanges and Clearing		2,700,000		2,500,000
NagaCorp		73,217,756		29,595,256
Europe
> United Kingdom
Intermediate Capital		864,000		0
Randgold Resources - ADR		212,000		0
> Netherlands
Aalberts Industries		2,005,935		1,750,935
> France
Iliad		246,000		0
SES		944,000		759,000
> Germany
Wincor Nixdorf		524,000		335,000
> Sweden
Hexagon		3,944,000		3,756,000
Nobia		4,572,226		3,362,226
> Ireland
Aryzta		600,000		330,000
Other Countries
> United States
Illumina		300,000		0
Latin America
> Mexico
Urbi Desarrollos Urbanos		18,000,000		15,000,000

See accompanying notes to financial statements.

33

Columbia Acorn International

Statement of Investments, December 31, 2009

Number of Shares			Value (000)
				Equities: 95.6%
Asia 38.7%
		> Japan 15.3%
	6,550,000	Kansai Paint	$	54,386
		Paint Producer in Japan, India, China & Southeast Asia
	31,500	Jupiter Telecommunications		31,208
		Largest Cable Service Provider in Japan
	12,500	Nippon Residential Investment (a)		30,372
		Residential REIT
	478,570	Point		26,719
		Apparel Specialty Retailer
	4,800	Orix JREIT		23,856
		Diversified REIT
	3,283,000	Kamigumi		23,855
		Port Cargo Handling & Logistics
	2,027,000	Rohto Pharmaceutical		23,331
		Health & Beauty Products
	640,000	Ibiden		22,793
		Electronic Parts & Ceramics
	1,016,000	Glory		22,468
		Currency Handling Systems & Related Equipment
	1,544,000	Aeon Delight		21,854
		Facility Maintenance & Management
	11,000	Seven Bank		21,847
		ATM Processing Services
	4,300	Osaka Securities Exchange		20,389
		Osaka Securities Exchange
	3,860	Nippon Accommodations Fund		20,121
		Residential REIT
	590,000	Makita		20,075
		Power Tools
	737,000	Kintetsu World Express		19,112
		Airfreight Logistics
	955,500	Aeon Mall		18,490
		Suburban Shopping Mall Developer, Owner & Operator
	1,905,500	Asics		17,060
		Footwear & Apparel
	7,500	Wacom		16,235
		Computer Graphic Illustration Devices
	3,050	Fukuoka		15,912
		Diversified REIT in Fukuoka
	787,200	Daiseki		15,850
		Waste Disposal & Recycling
	950,000	Ushio		15,815
		Industrial Light Sources
	643,000	Ain Pharmaciez		15,427
		Dispensing Pharmacy/Drugstore Operator
	480,000	Olympus		15,423
		Medical Equipment (Endoscopes) & Cameras
	193,000	Nakanishi		15,336
		Dental Tools & Machinery
	1,750,000	Suruga Bank		15,180
		Regional Bank
	587,800	Miura		14,838
		Industrial Boiler

Number of Shares			Value (000)
	580,000	Hamamatsu Photonics	$	14,008
		Optical Sensors for Medical & Industrial Applications
	633,800	Torishima Pump Manufacturing		13,701
		Industrial Pump for Power Generation & Water Supply Systems
	306,900	Benesse		12,834
		Education Service Provider
	345,000	Tsumura		11,112
		Traditional Chinese/Japanese Herbal Rx Drugs (Kampo)
	3,100,000	Chuo Mitsui Trust Holdings		10,346
		Trust Bank
	336,300	Unicharm PetCare		10,285
		Pet Food & Pet Toiletries
	2,470	Kakaku.com		9,590
		Online Price Comparison Services for Consumers
	822,000	Zenrin		9,478
		Map Content Publisher
	785,000	Tamron		7,928
		Camera Lens Maker
	312,000	Icom		6,690
		Two Way Radio Communication Equipment
	116,300	Toyo Tanso		5,604
		Carbon & Graphite Products for Industrial Use
	2,349	Start Today		4,278
		Online Apparel Mall
	208,900	As One		3,642
		Scientific Supplies Distributor
				677,448
		> China 5.8%
	10,107,000	China Yurun Food		29,827
		Meat Processor in China
	382,000	New Oriental Education & Technology - ADR (b)(c)		28,883
		China's Largest Private Education Service Provider
	31,987,000	Jiangsu Expressway		28,457
		Chinese Toll Road Operator
	29,166,400	China Green		27,607
		Chinese Fruit & Vegetable Grower & Processor
	240,000,000	RexLot Holdings		26,792
		Lottery Equipment Supplier in China
	703,800	Mindray - ADR (c)		23,873
		Medical Device Manufacturer
	11,764,400	Zhaojin Mining Industry		23,204
		Gold Mining & Refining in China
	6,000,000	Shandong Weigao		19,927
		Vertically Integrated Hospital Consumable Manufacturer
	15,782,000	Sino Ocean Land		14,455
		Property Developer in China
	12,316,000	Wasion Group		12,744
		Electronic Power Meter Total Solution Provider
	24,952,000	China Communication Services		12,203
		China's Telecom Infrastructure Service Provider
	1,000,000	VisionChina Media - ADR (b)		10,920
		Advertising on Digital Screens in China's Mass Transit System

See accompanying notes to financial statements.

34

Number of Shares			Value (000)
		> China—continued
	15,300,000	Fu Ji Food & Catering Services (b)(d)	$	158
		Food Catering Service Provider in China
				259,050
		> Singapore 4.9%
	35,000,000	Olam International		65,547
		Agriculture Supply Chain Manager
	7,000,000	Singapore Exchange		41,263
		Singapore Equity & Derivatives Market Operator
	70,000,000	Mapletree Logistics Trust		39,008
		Asian Logistics Landlord
	30,000,000	CDL Hospitality Trust		36,903
		Hotel Owner/Operator
	21,000,000	Ascendas REIT		32,887
		Singapore Industrial Property Landlord
				215,608
		> India 3.8%
	1,008,727	Asian Paints		38,681
		India's Largest Paint Company
	2,000,000	Jain Irrigation Systems		37,580
		Agricultural Micro-irrigation Systems & Food Processing
	450,000	Housing Development Finance		25,935
		Indian Mortgage Lender
	2,135,000	Shriram Transport Finance		22,132
		Truck Financing in India
	1,570,000	Mundra Port & Special Economic Zone		18,568
		Indian West Coast Shipping Port
	900,000	Educomp Solutions		13,690
		Multimedia Educational Content
	1,271,000	Patel Engineering		12,207
		Civil Engineering & Construction
				168,793
		> South Korea 3.3%
	245,000	NHN (b)		40,456
		South Korea's Largest Online Search Engine
	182,000	MegaStudy		37,291
		Online Education Service Provider
	909,000	Woongjin Coway		29,970
		South Korean Household Appliance Rental Service Provider
	376,000	Mirae Asset Securities		20,891
		South Korean Largest Diversified Financial Company
	298,000	Taewoong		19,069
		Niche Custom Forging
				147,677
		> Taiwan 2.9%
	55,734,000	Yuanta Financial Holdings		40,621
		Financial Holding Company in Taiwan
	9,297,575	Everlight Electronics		34,672
		LED Packager
	5,693,500	Simplo Technology		33,564
		World's Largest Notebook Battery Pack Supplier
	1,454,200	Formosa International Hotels		18,636
		Hotel, Food & Beverage Operation & Hospitality Management Services
				127,493

Number of Shares			Value (000)
		> Hong Kong 2.0%
	2,500,000	Hong Kong Exchanges and Clearing	$	44,506
		Hong Kong Equity & Derivatives Market Operator
	22,154,200	Lifestyle International		41,092
		Mid to High-end Department Store Operator in Hong Kong & China
	29,595,256	NagaCorp		3,269
		Casino/Entertainment Complex in Cambodia
				88,867
		> Indonesia 0.7%
	75,000,000	Perusahaan Gas Negara		30,975
		Gas Distributor & Pipeline Operator
				30,975
Asia: Total				1,715,911
Europe 36.9%
		> United Kingdom 6.9%
	6,500,000	Serco		55,261
		Facilities Management
	3,300,000	Capita Group		39,804
		White Collar, Back Office Outsourcing
	1,890,000	Intertek Group		38,055
		Testing, Inspection & Certification Services
	1,466,000	Schroders		31,293
		United Kingdom Top Tier Asset Manager
	6,800,000	Cobham		27,410
		Aerospace Components
	580,000	Chemring		27,293
		Defense Manufacturer of Countermeasures & Energetics
	4,600,000	RPS Group		15,996
		Environmental Consulting & Planning
	690,000	Tullow Oil		14,389
		Oil & Gas Producer
	3,465,000	N Brown Group		13,770
		Home Shopping Women's Clothes Retailer
	682,000	Rotork		13,053
		Valve Actuators for Oil & Water Pipelines
	1,250,000	Smith & Nephew		12,835
		Medical Equipment & Supplies
	1,110,000	Keller Group		11,477
		Ground Engineering
	4,722,884	Spice Group		4,611
		United Kingdom Utility Outsourcing
				305,247
		> Netherlands 6.8%
	1,871,250	Imtech		50,216
		Electromechanical & ICT Installation & Maintenance
	735,945	Fugro		42,028
		Sub-sea Oilfield Services
	520,100	Vopak		41,091
		World's Largest Operator of Petroleum & Chemical Storage Terminals
	1,372,989	Koninklijke TenCate (a)		36,081
		Advanced Textiles & Industrial Fabrics

See accompanying notes to financial statements.

35

Columbia Acorn International

Statement of Investments, continued

Number of Shares			Value (000)
		> Netherlands—continued
	1,385,000	Unit 4 Agresso (a)(b)	$	32,644
		Business Software Development
	339,146	Smit Internationale		29,195
		Harbor & Offshore Towage & Marine Services
	1,750,935	Aalberts Industries		25,015
		Flow Control & Heat Treatment
	1,088,187	Arcadis		24,480
		Engineering Consultants
	650,000	QIAGEN (b)		14,520
		Life Science Tools & Molecular Diagnostics
	62,000	Core Laboratories		7,323
		Oil & Gas Reservoir Consulting
				302,593
		> France 4.4%
	328,000	Neopost		27,100
		Postage Meter Machines
	506,362	Saft		24,392
		Niche Battery Manufacturer
	541,000	Zodiac Aerospace		22,577
		Leading Supplier to the Aerospace Industry
	271,000	Pierre & Vacances		20,888
		Vacation Apartment Lets
	531,176	Carbone Lorraine		19,149
		Advanced Industrial Materials
	583,000	Eutelsat		18,705
		Fixed Satellite Services
	759,000	SES		17,019
		Fixed Satellite Services
	170,000	Rubis		14,911
		Tank Storage & Liquefied Petroleum Gas Distribution
	259,664	Eurofins Scientific		14,126
		Food, Pharmaceuticals & Materials Screening & Testing
	160,701	Norbert Dentressangle		8,780
		Leading European Logistics & Transport Group
	966,229	Hi-Media (b)		6,768
		Online Advertiser in Europe
				194,415
		> Germany 4.3%
	700,000	CTS Eventim		34,175
		Event Ticket Sales
	245,000	Vossloh		24,408
		Rail Infrastructure & Diesel Locomotives
	335,000	Wincor Nixdorf		22,851
		Retail POS Systems & ATM Machines
	127,000	Rational		21,514
		Commercial Oven Manufacturer
	850,000	Rhoen-Klinikum		20,790
		Health Care Services
	750,000	Elringklinger		17,515
		Automobile Components
	1,180,000	Wirecard		16,223
		Online Payment Processing & Risk Management
	960,000	Tognum		15,927
		Diesel Engines for Drive & Power Generation Systems

Number of Shares			Value (000)
	354,500	Deutsche Beteiligungs	$	8,686
		Private Equity Investment Management
	700,000	Takkt		7,181
		Mail Order Retailer of Office & Warehouse Durables
				189,270
		> Switzerland 2.7%
	185,000	Geberit		32,770
		Plumbing Supplies
	20,500	Sika		31,891
		Chemicals for Construction & Industrial Applications
	275,000	Kuehne & Nagel		26,602
		Freight Forwarding/Logistics
	85,000	Burckhardt Compression		15,212
		Manufactures & Services Compressors
	349,882	Bank Sarasin & Cie (b)		13,223
		Private Banking
				119,698
		> Sweden 2.6%
	3,756,000	Hexagon		55,174
		Measurement Equipment
	3,887,000	Sweco		29,084
		Engineering Consultants
	3,362,226	Nobia (b)		19,704
		Kitchen Cabinet Manufacturing & Sales
	982,742	East Capital Explorer (b)		9,180
		Sweden-based RUS/CEE Investment Fund
				113,142
		> Italy 2.1%
	11,180,000	CIR (b)		28,868
		Italian Holding Company
	3,069,000	Credito Emiliano (b)		23,556
		Italian Regional Bank
	5,246,000	Terna		22,572
		Italian Power Transmission
	1,029,000	Ansaldo STS		19,525
		Leading Systems Integrator for the Railway Industry
				94,521
		> Finland 2.0%
	1,382,777	Stockmann		37,680
		Department Store & Fashion Retailer in Scandinavia & Russia
	1,756,000	Poyry		28,127
		Engineering Consultants
	2,170,000	Ramirent (b)		21,155
		Largest Equipment Rental Company in Scandinavia & Central Eastern Europe
				86,962
		> Ireland 1.2%
	8,100,000	United Drug		24,715
		Irish Pharmaceutical Wholesaler & Outsourcer
	448,000	Paddy Power		15,877
		Irish Betting Services
	330,000	Aryzta		12,091
		Baked Goods
				52,683

See accompanying notes to financial statements.

36

Number of Shares			Value (000)
		> Spain 0.9%
	573,000	Red Electrica de Espana	$	31,757
		Spanish Power Transmission
	1,546,000	ENCE (b)		5,968
		Europe's Leading Eucalyptus Pulp Maker
				37,725
		> Denmark 0.7%
	306,000	Novozymes		31,729
		Industrial Enzymes
				31,729
		> Poland 0.6%
	975,900	Central European Distribution (b)		27,725
		Vodka Production & Spirits Distribution
				27,725
		> Czech Republic 0.5%
	114,000	Komercni Banka		24,302
		Leading Czech Universal Bank
				24,302
		> Greece 0.5%
	3,725,000	Intralot		21,654
		Lottery & Gaming Systems & Services
				21,654
		> Portugal 0.4%
	3,909,580	Redes Energéticas Nacionais		16,794
		Portuguese Power Transmission & Gas Transportation
				16,794
		> Iceland 0.3%
	29,868,604	Marel (b)		14,881
		Largest Manufacturer of Poultry & Fish Processing Equipment
				14,881
Europe: Total				1,633,341
Other Countries 14.4%
		> Canada 4.2%
	3,927,000	Eldorado Gold (b)		56,022
		Gold Miner in Turkey, Greece, China & Brazil
	1,710,000	ShawCor		47,988
		Oil & Gas Pipeline Products
	1,117,000	CCL Industries		30,172
		Leading Global Label Manufacturer
	850,000	Ivanhoe Mines (b)		12,606
	744,000	Ivanhoe Mines (b)(e)		10,870
		Copper Mine Project in Mongolia
	432,900	Baytex		12,293
		Oil & Gas Producer in Canada
	1,480,610	Pan Orient (b)		10,759
		Growth Oriented & Return Focused Asian Explorer
	2,262,100	Horizon North Logistics (b)		3,569
		Provides Diversified Oil Service Offering in Northern Canada
				184,279

Number of Shares			Value (000)
		> United States 3.9%
	1,340,000	Atwood Oceanics (b)	$	48,039
		Offshore Drilling Contractor
	625,000	Alexion Pharmaceuticals (b)		30,513
		Biotech Focused on Orphan Diseases
	346,000	Oceaneering International (b)		20,248
		Provider of Sub-sea Services & Manufactured Products
	660,000	World Fuel Services		17,681
		Global Fuel Broker
	391,000	Bristow (b)		15,034
		Largest Provider of Helicopter Services to Offshore Oil & Gas Producers
	251,000	FMC Technologies (b)		14,518
		Oil & Gas Wellhead Manufacturer
	725,000	BioMarin (b)		13,637
		Biotech Focused on Orphan Diseases
	430,000	Ritchie Brothers Auctioneers (c)		9,645
		Heavy Equipment Auctioneer
	324,000	Tesco (b)		4,183
		Developing New Well Drilling Technologies
				173,498
		> Australia 2.6%
	2,068,000	United Group		26,333
		Engineering & Facilities Management
	700,000	Perpetual Trustees		23,103
		Mutual Fund Management
	700,000	Australian Stock Exchange		21,801
		Australian Equity & Derivatives Market Operator
	2,000,000	Billabong International		19,444
		Action Sports Apparel Brand Manager
	262,000	Cochlear		16,178
		Cochlear Implants for Hearing
	731,000	Seek		4,492
		Online Job Listing & Education
	460,092	SAI Global		1,655
		Publishing, Certification & Compliance Services
	555,740	Hastie Group		938
		Mechanical, Electrical & Hydraulic (MEH) Engineering
				113,944
		> South Africa 2.5%
	1,973,000	Naspers		80,067
		Media in Africa & Other Emerging Markets
	4,600,000	Mr. Price		21,734
		South African Retailer of Apparel, Household & Sporting Goods
	3,049,000	Uranium One (b)		8,804
		Uranium Mines in Kazakhstan, the U.S. & Australia
				110,605
		> Israel 0.8%
	2,890,000	Israel Chemicals		37,734
		Producer of Potash, Phosphates, Bromine & Specialty Chemicals
				37,734

See accompanying notes to financial statements.

37

Columbia Acorn International

Statement of Investments, continued

Number of Shares or Principal Amount (000)			Value (000)
		> Kazakhstan 0.4%
	1,770,000	Halyk Savings Bank of Kazakhstan - GDR (b)	$	16,798
		Largest Retail Bank & Insurer in Kazakhstan
				16,798
Other Countries: Total				636,858
Latin America 5.6%
		> Brazil 3.3%
	5,000,000	Localiza Rent A Car		55,184
		Car Rental
	4,300,000	Suzano		50,075
		Brazilian Pulp & Paper Producer
	2,000,000	Natura		41,679
		Direct Retailer of Cosmetics
				146,938
		> Mexico 1.6%
	700,000	Grupo Aeroportuario del Sureste - ADR		36,267
		Mexican Airport Operator
	15,000,000	Urbi Desarrollos Urbanos (b)		33,825
		Affordable Housing Builder
				70,092
		> Chile 0.7%
	862,000	Sociedad Quimica y Minera de Chile - ADR		32,385
		Producer of Specialty Fertilizers, Lithium & Iodine
				32,385
Latin America: Total				249,415
Total Equities: 95.6% (Cost: $3,179,286)				4,235,525
Securities Lending Collateral: 0.6%
	26,644,150	Dreyfus Government Cash Management Fund (7 day yield of 0.000%) (f)		26,644
Total Securities Lending Collateral: (Cost: $26,644)				26,644
Short-Term Obligations: 3.5%
		> Repurchase Agreement 3.0%
$	131,378	Repurchase Agreement with Fixed Income Clearing Corp., dated 12/31/09, due 1/04/10 at 0.00%, collateralized by a U.S. Treasury obligation, maturing 3/18/10, market value $134,007 (repurchase proceeds $131,378)		131,378
				131,378

Principal Amount (000)			Value (000)
		> Commercial Paper 0.5%
$	21,900	Toyota Motor Credit 0.16% due 1/04/10	$	21,900
				21,900
Total Short-Term Obligations: (Amortized Cost: $153,278)				153,278
Total Investments: 99.7% (Cost: $3,359,208)(g)(h)				4,415,447
Obligation to Return Collateral for Securities Loaned: (0.6)%				(26,644	)
Cash and Other Assets Less Liabilities: 0.9%				41,935
Total Net Assets: 100.0%			$	4,430,738

ADR = American Depositary Receipts.

GDR = Global Depositary Receipts.

See accompanying notes to financial statements.

38

> Notes to Statements of Investments (dollar values in thousands)

(a)  An affiliated person of the Fund may include any company in which the Fund owns five percent or more of its outstanding voting shares. Holdings and transactions in these affiliated companies during the twelve months ended December 31, 2009, are as follows:

Affiliates	Balance of Shares Held 12/31/08		Purchases/ Additions			Sales/ Reductions		Balance of Shares Held 12/31/09		Value		Dividend
Ain Pharmaciez*		643,000		-			-		643,000	$	15,427	$	185
Koninklijke TenCate		1,556,239		78,456	**		261,706		1,372,989		36,081		725
Nippon Residential Investment		5,200		7,300			-		12,500		30,372		2,090
Unit 4 Aggresso		1,385,000		-			-		1,385,000		32,644		-
Total of Affiliated Transactions		3,589,439		85,756			261,706		3,413,489	$	114,524	$	3,000

*  At December 31, 2009, the Fund owned less than five percent of the company's outstanding voting shares.

**  Includes the effect of a 2:1 stock split.

  The aggregate cost and value of these companies at December 31, 2009, were $77,410 and $114,524, respectively. Investments in affiliated companies represented 2.6% of total net assets at December 31, 2009.

(b)  Non-income producing security.

(c)  All or a portion of this security was on loan at December 31, 2009. The total market value of Fund securities on loan at December 31, 2009 was $25,743.

(d)  Illiquid security.

(e)  Security is traded on a U.S. exchange.

(f)  Investment made with cash collateral received from securities lending activity.

(g)  At December 31, 2009, for federal income tax purposes, the cost of investments was $3,397,978 and net unrealized apppreciation was $1,017,469, consisting of gross unrealized appreciation of $1,265,386 and gross unrealized depreciation of $247,917.

(h)  On December 31, 2009, the Fund's total investments were denominated in currencies as follows:

Currency	Value		Percentage of Net Assets
Euro	$	989,294		22.3
Japanese Yen		677,448		15.3
U.S. Dollar		548,464		12.4
British Pound		305,247		6.9
Hong Kong Dollar		284,241		6.4
Other currencies less than 5% of total net assets		1,610,753		36.4
	$	4,415,447		99.7

See accompanying notes to financial statements.

39

Columbia Acorn International

Statement of Investments, continued

> Notes to Statements of Investments (dollar values in thousands)

  At December 31, 2009, the Fund had entered into the following forward foreign currency exchange contracts:

Forward Foreign Currency Exchange Contracts to Sell	Forward Foreign Currency Exchange Contracts to Buy	Principal Amount in Foreign Currency		Principal Amount in U.S. Dollar		Settlement Date	Unrealized Appreciation
USD	CAD		26,337	$	25,000	2/12/10	$	183
USD	CAD		26,474		25,000	3/15/10		313
EUR	USD		43,638		65,000	1/15/10		2,443
EUR	USD		43,678		65,000	2/12/10		2,389
EUR	USD		44,397		65,000	3/15/10		1,361
				$	245,000		$	6,689
Forward Foreign Currency Exchange Contracts to Buy	Forward Foreign Currency Exchange Contracts to Sell	Principal Amount in Foreign Currency		Principal Amount in U.S. Dollar		Settlement Date	Unrealized (Depreciation)
AUD	USD		16,544	$	15,000	1/15/10	$	(155	)
AUD	USD		16,324		15,000	2/12/10		(393	)
AUD	USD		16,531		15,000	3/15/10		(256	)
CAD	USD		25,674		25,000	1/15/10		(452	)
JPY	USD		2,234,275		25,000	1/15/10		(1,009	)
JPY	USD		2,259,250		25,000	2/12/10		(737	)
JPY	USD		2,215,575		25,000	3/15/10		(1,203	)
				$	145,000		$	(4,205	)

The counterparty for all forward foreign currency exchange contracts is State Street Bank and Trust Company.

AUD = Australian Dollar

CAD = Canadian Dollar

EUR = Euro

JPY = Japanese Yen

USD = United States Dollar

The following table summarizes the inputs used, as of December 31, 2009, in valuing the Fund's assets:

Investment Type	Quoted Prices (Level 1)		Other Significant Observable Inputs (Level 2)			Significant Unobservable Inputs (Level 3)		Total
Equities
Asia	$	63,676	$	1,652,077		$	158	$	1,715,911
Europe		35,048		1,598,293			-		1,633,341
Other Countries		366,581		270,277			-		636,858
Latin America		102,477		146,938			-		249,415
Total Equities		567,782		3,667,585			158		4,235,525
Total Securities Lending Collateral		26,644		-			-		26,644
Total Short-Term Obligations		-		153,278			-		153,278
Total Investments	$	594,426	$	3,820,863		$	158	$	4,415,447
Net Unrealized Appreciation on Forward Foreign Currency Exchange Contracts		-		6,689			-		6,689
Net Unrealized Depreciation on Forward Foreign Currency Exchange Contracts		-		(4,205	)		-		(4,205	)
Total	$	594,426	$	3,823,347		$	158	$	4,417,931

  The Fund's assets assigned to the Level 2 input category include certain foreign securities for which a third party statistical pricing service may be employed for purposes of fair market valuation.

See accompanying notes to financial statements.

40

> Notes to Statements of Investments (dollar values in thousands)

The following table reconciles asset balances for the twelve-month period ending December 31, 2009, in which significant unobservable inputs (Level 3) were used in determining value:

Investments in Securities	Balance as of December 31, 2008		Accrued Discounts/ Premiums		Realized Gain/(Loss)		Change in Unrealized Appreciation (Depreciation)			Net Purchases (Sales)		Net Transfers into (out of) Level 3		Balance as of December 31, 2009
Equities
Asia	$	312	$	-	$	-	$	(13,049	)	$	-	$	12,895	$	158
	$	312	$	-	$	-	$	(13,049	)	$	-	$	12,895	$	158

  The information in the above reconciliation table represents fiscal year to date activity for any securities identified as using Level 3 inputs during the current fiscal period.

  The change in unrealized appreciation (depreciation) attributed to securities owned at December 31, 2009, which were valued using significant unobservable inputs (Level 3) amounted to $(13,049). This amount is included in net change in unrealized appreciation on the Statements of Changes in Net Assets.

  For more information on valuation inputs, and their aggregation into the levels used in the tables above, please refer to the Security Valuation section in the accompanying Notes to Financial Statements.

See accompanying notes to financial statements.

41

Columbia Acorn International

Portfolio Diversification

At December 31, 2009, the Fund's portfolio investments as a percent of net assets were diversified as follows:

	Value (000)		Percentage of Net Assets
> Industrial Goods & Services
Other Industrial Services	$	378,257		8.5
Industrial Materials & Specialty Chemicals		306,733		6.9
Machinery		272,568		6.2
Outsourcing Services		165,223		3.7
Electrical Components		100,514		2.3
Conglomerates		76,676		1.7
Construction		66,099		1.5
Industrial Distribution		3,642		0.1
		1,369,712		30.9
> Consumer Goods & Services
Nondurables		105,466		2.4
Retail		100,417		2.3
Educational Services		79,008		1.8
Travel		76,072		1.7
Apparel		74,184		1.7
Other Consumer Services		71,062		1.6
Food & Beverage		69,684		1.6
Casinos & Gaming		67,592		1.5
Other Entertainment		52,811		1.2
Consumer Goods Distribution		27,725		0.6
Furniture & Textiles		19,704		0.4
Consumer Electronics		7,928		0.2
		751,653		17.0
> Information
Financial Processors		101,992		2.3
TV Broadcasting		80,067		1.8
Computer Hardware & Related Equipment		72,650		1.6
Instrumentation		69,182		1.6
Internet Related		54,538		1.2
Satellite Broadcasting & Services		35,724		0.8
Semiconductors & Related Equipment		34,672		0.8
Business Software		32,644		0.7
CATV		31,208		0.7
Publishing		23,168		0.5
Advertising		17,688		0.4
Business Information & Marketing Services		15,996		0.4
Telecommunications Equipment		12,203		0.3
Mobile Communications		6,690		0.2
		588,422		13.3
> Energy & Minerals
Oil Services		195,606		4.4
Mining		118,830		2.7
Oil Refining, Marketing & Distribution		86,977		2.0

	Value (000)			Percentage of Net Assets
Agricultural Commodities	$	50,075			1.1
Oil & Gas Producers		37,442			0.9
Other Resources		5,968			0.1
		494,898			11.2
> Other Industries
Real Estate		247,339			5.6
Transportation		144,236			3.2
Regulated Utilities		71,123			1.6
		462,698			10.4
> Finance
Brokerage & Money Management		168,798			3.8
Banks		112,029			2.5
Finance Companies		42,521			1.0
Savings & Loans		25,935			0.6
		349,283			7.9
> Health Care
Medical Equipment & Devices		134,085			3.0
Pharmaceuticals		35,827			0.8
Health Care Services		20,790			0.5
Medical Supplies		14,520			0.3
Biotechnology & Drug Delivery		13,637			0.3
		218,859			4.9
Total Equities:		4,235,525			95.6
Securities Lending Collateral:		26,644			0.6
Short-Term Obligations:		153,278			3.5
Total Investments:		4,415,447			99.7
Obligation to Return Collateral for Securities Loaned:		(26,644	)		(0.6	)
Cash and Other Assets Less Liabilities:		41,935			0.9
Net Assets:	$	4,430,738			100.0

See accompanying notes to financial statements.

42

Columbia Acorn USA

Major Portfolio Changes in the Fourth Quarter (Unaudited)

	Number of Shares
	09/30/09		12/31/09
Purchases
Information
AboveNet		0		45,000
Blue Coat Systems		210,100		389,100
ExlService Holdings		0		248,698
Monolithic Power Systems		340,000		500,000
PAETEC Holding		1,591,800		2,250,000
Plexus		115,000		165,000
Supertex		189,296		287,000
Consumer Goods & Services
Abercrombie & Fitch		281,000		431,000
Diamond Foods		0		97,814
Lifetime Fitness		110,000		182,000
Vail Resorts		150,000		220,000
Industrial Goods & Services
GrafTech International		200,000		540,000
Pentair		500,000		585,000
Energy & Minerals
Atwood Oceanics		720,000		755,000
Bristow		0		105,000
Health Care
Acorda Therapeutics		0		199,000
Allos Therapeutics		341,000		565,000
Gen-Probe		0		46,500
Mednax		0		45,000
Nanosphere		0		199,720

	Number of Shares
	09/30/09		12/31/09
Sales
Information
Amphenol		295,600		285,600
Cogent Communications		840,000		444,800
Concur Technologies		223,000		158,000
Micros Systems		695,100		620,000
Polycom		525,000		480,000
Switch & Data Facilities		947,000		510,000
Consumer Goods & Services
Hot Topic		497,714		0
Jarden		298,000		154,000
Industrial Goods & Services
Greif		50,000		0
Mine Safety Appliances		155,000		77,000
Quanta Services		350,000		110,000
Energy & Minerals
FMC Technologies		598,400		500,000
Oceaneering International		130,111		95,000
Health Care
Cephalon		125,000		56,000
Charles River Laboratories		67,000		0
Emdeon		148,000		0
Human Genome Sciences		335,000		298,000
InterMune		187,000		127,800
Luminex		205,000		0
Myriad Genetics		153,466		113,466
Nektar Therapeutics		500,000		357,000
Onyx Pharmaceuticals		75,000		0
Poniard		290,184		0
Psychiatric Solutions		287,000		170,000
Other Industries
Heartland Express		524,720		344,720

See accompanying notes to financial statements.

43

Columbia Acorn USA

Statement of Investments, December 31, 2009

Number of Shares			Value (000)
				Equities: 99.7%
Information 35.4%
		> Business Software 7.7%
	1,155,000	Informatica (a)	$	29,868
		Enterprise Data Integration Software
	620,000	Micros Systems (a)		19,239
		Information Systems for Restaurants & Hotels
	375,000	ANSYS (a)		16,297
		Simulation Software for Engineers & Designers
	525,000	Blackbaud		12,406
		Software & Services for Non-profits
	2,100,000	Novell (a)		8,715
		Directory, Operating System & Identity Management Software
	158,000	Concur Technologies (a)		6,755
		Web Enabled Cost & Expense Management Software
	240,000	NetSuite (a)(b)		3,835
		End to End IT Systems Solutions Delivered Over the Web
	57,000	Quality Systems		3,578
		IT Systems for Medical Groups & Ambulatory Care Centers
	108,213	Tyler Technologies (a)		2,155
		Financial, Tax, Court & Document Management Systems for Government
	307,352	Art Technology Group (a)		1,386
		Software & Tools to Optimize Websites for E-commerce
	100,000	Avid Technology (a)		1,276
		Digital Nonlinear Editing Software & Systems
	230,000	Actuate (a)		984
		Information Delivery Software & Solutions
	10,800	Blackboard (a)		490
		Education Software
				106,984
		> Semiconductors & Related Equipment 4.4%
	760,000	Microsemi (a)		13,490
		Analog/Mixed-signal Semiconductors
	500,000	Monolithic Power Systems (a)		11,985
		High Performance Analog & Mixed-signal Integrated Circuits (ICs)
	1,179,750	ON Semiconductor (a)		10,394
		Mixed-signal & Power Management Semiconductors
	287,000	Supertex (a)		8,553
		Analog/Mixed-signal Semiconductors
	1,168,000	Integrated Device Technology (a)		7,557
		Communications Semiconductors
	480,000	Pericom Semiconductor (a)		5,534
		Interface Integrated Circuits (ICs) & Frequency Control Products
	750,000	Entegris (a)		3,960
		Semiconductor Materials Management Products
				61,473
		> Mobile Communications 3.8%
	1,250,000	Crown Castle International (a)		48,800
		Communications Towers

Number of Shares			Value (000)
	130,000	SBA Communications (a)	$	4,441
		Communications Towers
	88,000	Globalstar (a)(b)		76
		Satellite Mobile Voice & Data Carrier
				53,317
		> Telephone and Data Services 3.8%
	2,061,000	tw telecom (a)		35,326
		Fiber Optic Telephone/Data Services
	2,250,000	PAETEC Holding (a)		9,337
		Telephone/Data Services for Business
	444,800	Cogent Communications (a)		4,386
		Internet Data Pipelines
	45,000	AboveNet (a)		2,927
		Metropolitan Fiber Communications Services
				51,976
		> Instrumentation 3.4%
	180,000	Mettler Toledo (a)		18,898
		Laboratory Equipment
	775,000	IPG Photonics (a)		12,973
		Fiber Lasers
	350,000	FLIR Systems (a)		11,452
		Infrared Cameras
	168,000	Trimble Navigation (a)		4,234
		GPS-based Instruments
				47,557
		> Computer Hardware & Related Equipment 3.3%
	505,000	II-VI (a)		16,059
		Laser Optics & Specialty Materials
	285,600	Amphenol		13,189
		Electronic Connectors
	280,000	Nice Systems - ADR (Israel) (a)		8,691
		Audio & Video Recording Solutions
	184,000	Zebra Technologies (a)		5,219
		Bar Code Printers
	135,000	Netgear (a)		2,928
		Networking Products for Small Business & Home
				46,086
		> Telecommunications Equipment 2.3%
	480,000	Polycom (a)		11,986
		Video Conferencing Equipment
	389,100	Blue Coat Systems (a)		11,105
		WAN Acceleration & Network Security
	335,000	CommScope (a)		8,887
		Wireless Infrastructure Equipment & Telecom Cable
				31,978
		> Financial Processors 1.8%
	463,000	Global Payments		24,937
		Credit Card Processor
				24,937
		> Gaming Equipment & Services 1.7%
	570,000	Bally Technologies (a)		23,535
		Slot Machines & Software
				23,535

See accompanying notes to financial statements.

44

Number of Shares			Value (000)
		> Computer Services 1.4%
	395,000	SRA International (a)	$	7,545
		Government IT Services
	248,698	ExlService Holdings (a)		4,516
		Business Process Outsourcing
	1,005,500	Hackett Group (a)		2,795
		IT Integration & Best Practice Research
	235,000	iGate		2,350
		IT & Business Process Outsourcing Services
	786,000	RCM Technologies (a)(c)		1,949
		Technology & Engineering Services
				19,155
		> Internet Related 0.8%
	510,000	Switch & Data Facilities (a)		10,307
		Network Neutral Data Centers
	381,740	TheStreet.com		916
		Financial Information Websites
				11,223
		> Contract Manufacturing 0.3%
	165,000	Plexus (a)		4,703
		Electronic Manufacturing Services
				4,703
		> Radio 0.3%
	511,100	Salem Communications (a)		3,062
		Radio Stations for Religious Programming
	705,500	Spanish Broadcasting System (a)		550
		Spanish Language Radio Stations
	18,750	Saga Communications (a)		235
		Radio Stations in Small & Mid-sized Cities
				3,847
		> TV Broadcasting 0.3%
	975,000	Entravision Communications (a)		3,315
		Spanish Language TV & Radio Stations
				3,315
		> CATV 0.1%
	335,000	Mediacom Communications (a)		1,498
		Cable Television Franchises
				1,498
Information: Total				491,584
Consumer Goods & Services 16.6%
		> Retail 6.1%
	431,000	Abercrombie & Fitch		15,021
		Teen Apparel Retailer
	402,000	Urban Outfitters (a)		14,066
		Apparel & Home Specialty Retailer
	281,000	J Crew Group (a)		12,572
		Multi-channel Branded Retailer
	390,000	lululemon athletica (a)		11,739
		Premium Active Apparel Retailer
	824,000	Chico's FAS (a)		11,577
		Women's Specialty Retailer
	875,000	Saks (a)		5,740
		Luxury Department Store Retailer
	480,000	Talbots (a)(b)		4,277
		Women's Specialty Retailer

Number of Shares			Value (000)
	658,000	Charming Shoppes (a)	$	4,257
		Women's Specialty Plus Size Apparel Retailer
	55,000	Gymboree (a)		2,392
		Children's Apparel Specialty Retailer
	165,000	AnnTaylor Stores (a)		2,251
		Women's Apparel Retailer
	17,100	Rue21 (a)		480
		Fashion Value Apparel Retailer
				84,372
		> Travel 3.1%
	750,000	Gaylord Entertainment (a)		14,813
		Convention Hotels
	797,750	Avis Budget Group (a)		10,466
		Second Largest Car Rental Company
	750,000	Hertz (a)		8,940
		Largest U.S. Rental Car Operator
	220,000	Vail Resorts (a)		8,316
		Ski Resort Operator & Developer
				42,535
		> Educational Services 1.6%
	192,000	ITT Educational Services (a)		18,424
		Post-secondary Degree Services
	165,000	Universal Technical Institute (a)		3,333
		Vocational Training
				21,757
		> Furniture & Textiles 1.4%
	980,000	Knoll		10,124
		Office Furniture
	285,000	Herman Miller		4,554
		Office Furniture
	540,000	Interface		4,487
		Modular & Broadloom Carpet
				19,165
		> Apparel 1.0%
	222,200	Coach		8,117
		Designer & Retailer of Branded Leather Accessories
	284,313	True Religion Apparel (a)		5,257
		Premium Denim
				13,374
		> Other Durable Goods 0.8%
	327,900	Cavco Industries (a)(c)		11,778
		Manufactured Homes
				11,778
		> Consumer Goods Distribution 0.7%
	523,500	Pool		9,988
		Distributor of Swimming Pool Supplies & Equipment
				9,988
		> Food & Beverage 0.5%
	97,814	Diamond Foods		3,476
		Culinary Ingredients & Snack Foods
	90,000	Hansen Natural (a)		3,456
		Alternative Beverages
				6,932

See accompanying notes to financial statements.

45

Columbia Acorn USA

Statement of Investments, continued

Number of Shares			Value (000)
		> Leisure Products 0.4%
	180,000	Thor Industries	$	5,652
		RV & Bus Manufacturer
				5,652
		> Nondurables 0.3%
	154,000	Jarden		4,760
		Branded Household Products
				4,760
		> Other Consumer Services 0.3%
	182,000	Lifetime Fitness (a)(b)		4,537
		Sport & Fitness Club Operator
				4,537
		> Casinos & Gaming 0.3%
	455,000	Pinnacle Entertainment (a)		4,086
		Regional Casino Operator
				4,086
		> Restaurants 0.1%
	40,000	P.F. Chang's China Bistro (a)(b)		1,517
		Mandarin Style Restaurants
				1,517
Consumer Goods & Services: Total				230,453
Industrial Goods & Services 13.3%
		> Machinery 9.4%
	627,500	Ametek		23,996
		Aerospace/Industrial Instruments
	373,600	Nordson		22,857
		Dispensing Systems for Adhesives & Coatings
	587,000	ESCO Technologies		21,044
		Automatic Electric Meter Readers
	445,000	Donaldson		18,930
		Industrial Air Filtration
	585,000	Pentair		18,895
		Pumps & Water Treatment
	235,000	Oshkosh		8,702
		Specialty Truck Manufacturer
	195,000	MOOG (a)		5,700
		Motion Control Products for Aerospace, Defense & Industrial Markets
	100,000	HEICO		3,596
		FAA Approved Aircraft Replacement Parts
	71,800	Toro		3,002
		Turf Maintenance Equipment
	77,000	Mine Safety Appliances		2,043
		Safety Equipment
	50,000	Kaydon		1,788
		Specialized Friction & Motion Control Products
				130,553
		> Industrial Materials & Specialty Chemicals 0.9%
	255,000	Drew Industries (a)		5,266
		RV & Manufactured Home Components
	150,000	Albany International		3,369
		Paper Machine Clothing & Advanced Textiles
	60,000	Albemarle		2,182
		Refinery Catalysts & Other Specialty Chemicals

Number of Shares			Value (000)
	65,000	Koppers Holdings	$	1,979
		Integrated Provider of Carbon Compounds
				12,796
		> Steel 0.6%
	540,000	GrafTech International (a)		8,397
		Industrial Graphite Materials Producer
				8,397
		> Other Industrial Services 0.5%
	265,000	TrueBlue (a)		3,925
		Temporary Manual Labor
	396,000	American Reprographics (a)		2,776
		Document Management & Logistics
				6,701
		> Industrial Distribution 0.4%
	350,000	Interline Brands (a)		6,044
		Industrial Distribution
				6,044
		> Electrical Components 0.4%
	145,000	Acuity Brands		5,168
		Commercial Lighting Fixtures
				5,168
		> Construction 0.4%
	240,000	M/I Homes (a)		2,494
		Columbus-based Home Builder
	110,000	Ritchie Brothers Auctioneers (b)		2,467
		Heavy Equipment Auctioneer
				4,961
		> Waste Management 0.3%
	130,000	Waste Connections (a)		4,334
		Solid Waste Management
				4,334
		> Water 0.2%
	550,000	Mueller Water Products		2,860
		Fire Hydrants, Valves & Ductile Iron Pipes
				2,860
		> Outsourcing Services 0.2%
	110,000	Quanta Services (a)		2,292
		Electrical & Telecom Construction Services
				2,292
Industrial Goods & Services: Total				184,106
Finance 12.5%
		> Finance Companies 5.1%
	1,136,500	AmeriCredit (a)		21,639
		Auto Lending
	407,900	World Acceptance (a)		14,615
		Personal Loans
	365,000	GATX		10,494
		Rail Car Lessor
	345,000	McGrath Rentcorp		7,714
		Temporary Space & IT Rentals
	275,000	Aaron's (b)		7,626
		Rent to Own
	625,000	H&E Equipment Services (a)		6,556
		Heavy Equipment Leasing

See accompanying notes to financial statements.

46

Number of Shares			Value (000)
		> Finance Companies—continued
	230,000	CAI International (a)	$	2,077
		International Container Leasing
	99,200	Marlin Business Services (a)		786
		Small Equipment Leasing
				71,507
		> Banks 4.4%
	935,182	Valley National Bancorp (b)		13,214
		New Jersey/New York Bank
	492,125	MB Financial		9,705
		Chicago Bank
	659,800	TCF Financial		8,986
		Great Lakes Bank
	403,788	Lakeland Financial		6,965
		Indiana Bank
	508,000	Pacific Continental		5,811
		Pacific N.W. Bank
	127,200	SVB Financial Group (a)		5,303
		Bank to Venture Capitalists
	213,600	Associated Banc-Corp		2,352
		Midwest Bank
	215,000	Eagle Bancorp (a)		2,251
		Metro D.C. Bank
	500,000	First Busey		1,945
		Illinois Bank
	140,000	Wilmington Trust		1,728
		Delaware Trust Bank
	90,000	TriCo Bancshares		1,498
		California Central Valley Bank
	851,247	Guaranty Bancorp (a)		1,124
		Colorado Bank
	247,203	Green Bankshares (b)		878
		Tennessee Bank
				61,760
		> Brokerage & Money Management 1.4%
	280,000	Eaton Vance		8,515
		Specialty Mutual Funds
	750,000	MF Global (a)		5,212
		Futures Broker
	155,000	Investment Technology Group (a)		3,054
		Electronic Trading
	150,000	SEI Investments		2,628
		Mutual Fund Administration & Investment Management
				19,409
		> Savings & Loans 1.0%
	600,000	ViewPoint Financial		8,646
		Texas Thrift
	238,090	Berkshire Hills Bancorp		4,924
		Northeast Thrift
	42,231	K-Fed Bancorp (b)		371
		Los Angeles Savings & Loan
				13,941
		> Insurance 0.6%
	120,000	Tower Group		2,809
		Commercial & Personal Lines Insurance

Number of Shares			Value (000)
	110,000	Delphi Financial Group	$	2,461
		Workers Compensation & Group Employee Benefit Products & Services
	7,000	Markel (a)		2,380
		Specialty Insurance
				7,650
Finance: Total				174,267
Energy & Minerals 8.9%
		> Oil Services 5.0%
	500,000	FMC Technologies (a)		28,920
		Oil & Gas Wellhead Manufacturer
	755,000	Atwood Oceanics (a)		27,067
		Offshore Drilling Contractor
	95,000	Oceaneering International (a)		5,559
		Provider of Sub-sea Services & Manufactured Products
	105,000	Bristow (a)		4,037
		Largest Provider of Helicopter Services to Offshore Oil & Gas Producers
	115,375	Exterran Holdings (a)		2,475
		Natural Gas Compressor Rental & Fabrication
	106,000	Tesco (a)		1,369
		Developing New Well Drilling Technologies
				69,427
		> Oil & Gas Producers 3.0%
	925,000	Quicksilver Resources (a)		13,884
		Natural Gas & Coal Steam Gas Producer
	485,000	Carrizo Oil & Gas (a)		12,848
		Oil & Gas Producer
	218,800	Southwestern Energy (a)		10,546
		Oil & Gas Producer
	111,200	Equitable Resources		4,884
		Natural Gas Producer & Utility
				42,162
		> Mining 0.5%
	50,000	Core Laboratories (Netherlands)		5,906
		Oil & Gas Reservoir Consulting
	143,247	PolyMet Mining (a)		438
		Copper & Nickel Miner
				6,344
		> Other Resources 0.4%
	218,000	Layne Christensen (a)		6,259
		Oil & Gas Production/Engineering & Construction/Contract Drilling
				6,259
Energy & Minerals: Total				124,192
Health Care 8.4%
		> Biotechnology & Drug Delivery 3.6%
	298,000	Human Genome Sciences (a)		9,119
		Biotech Focused on HCV, Inflammation & Cancer
	199,000	Acorda Therapeutics (a)		5,019
		Biopharma Company Focused on Nervous Disorder Drugs
	266,000	BioMarin (a)		5,003
		Biotech Focused on Orphan Diseases

See accompanying notes to financial statements.

47

Columbia Acorn USA

Statement of Investments, continued

Number of Shares			Value (000)
		> Biotechnology & Drug Delivery—continued
	488,784	Seattle Genetics (a)	$	4,966
		Antibody-based Therapies for Cancer
	157,000	Auxilium Pharmaceuticals (a)		4,707
		Biotech Focused on Niche Disease Areas
	565,000	Allos Therapeutics (a)		3,712
		Cancer Drug Development
	65,000	United Therapeutics (a)		3,422
		Biotech Focused on Rare Diseases
	357,000	Nektar Therapeutics (a)		3,327
		Drug Delivery Technologies
	85,000	AMAG Pharmaceuticals (a)		3,233
		Biotech Focused on Niche Diseases
	113,466	Myriad Genetics (a)		2,961
		Genetic Diagnostics
	500,000	NPS Pharmaceuticals (a)		1,700
		Orphan Drugs & Healthy Royalties
	127,800	InterMune (a)		1,667
		Drugs for Pulmonary Fibrosis & Hepatitis C
	225,000	Micromet (a)(b)		1,499
		Next-generation Antibody Technology
	18,181	Metabolex, Series A-1 (a)(d)		22
		Diabetes Drug Development
	738,060	Medicure - Warrants (a)(d)		7
		Cardiovascular Biotech Company
	100,000	IsoRay - Warrants (a)(d)		2
		Radiology Cancer Company
	37,500	Locus Pharmaceuticals, Series A-1, Pfd. (a)(d)		2
	19,329	Locus Pharmaceuticals, Series B-1, Pfd. (a)(d)		1
		High Throughput Rational Drug Design
				50,369
		> Medical Equipment & Devices 2.0%
	235,000	Alexion Pharmaceuticals (a)		11,473
		Biotech Focused on Orphan Diseases
	134,000	Illumina (a)		4,107
		Leading Tools & Service Provider for Genetic Analysis
	85,000	Orthofix International (a)		2,632
		Bone Fixation & Stimulation Devices
	80,000	Sirona Dental Systems (a)		2,539
		Manufacturer of Dental Equipment
	46,500	Gen-Probe (a)		1,995
		Molecular In-vitro Diagnostics
	100,000	American Medical Systems (a)		1,929
		Medical Devices to Treat Urological Conditions
	40,000	Kinetic Concepts (a)		1,506
		Wound Healing & Tissue Repair Products
	199,720	Nanosphere (a)		1,286
		Molecular Diagnostics Company with Best of Breed Platform
				27,467
		> Health Care Services 1.6%
	606,300	PSS World Medical (a)		13,684
		Distributor of Medical Supplies
	170,000	Psychiatric Solutions (a)		3,594
		Behavioral Health Services

Number of Shares			Value (000)
	45,000	Mednax (a)	$	2,705
		Physician Management for Pediatric & Anesthesia Practices
	283,000	eResearch Technology (a)		1,701
		Clinical Research Services
				21,684
		> Medical Supplies 1.0%
	318,000	Cepheid (a)		3,969
		Molecular Diagnostics
	180,000	Immucor (a)		3,643
		Automated Blood Typing Reagents
	43,000	Techne		2,948
		Cytokines, Antibodies & Other Reagents for Life Science
	53,000	Idexx Laboratories (a)(b)		2,832
		Diagnostic Equipment & Services for Veterinarians
				13,392
		> Pharmaceuticals 0.2%
	56,000	Cephalon (a)		3,495
		Specialty Pharmaceuticals for Pain, Central Nervous System & Oncology
				3,495
Health Care: Total				116,407
Other Industries 4.6%
		> Real Estate 4.1%
	405,000	SL Green Realty		20,347
		Manhattan Office Buildings
	276,796	Macerich (b)		9,951
		Regional Shopping Malls
	170,000	Corporate Office Properties		6,227
		Office Buildings
	1,450,000	Kite Realty Group		5,902
		Community Shopping Centers
	100,000	Digital Realty Trust		5,028
		Technology-focused Office Buildings
	90,000	American Campus Communities		2,529
		Student Housing
	470,000	DCT Industrial Trust		2,359
		Industrial Properties
	196,000	Extra Space Storage		2,264
		Self Storage Facilities
	120,000	BioMed Realty Trust		1,894
		Life Science-focused Office Buildings
				56,501
		> Transportation 0.5%
	344,720	Heartland Express		5,264
		Regional Trucker
	180,000	Rush Enterprises, Class A (a)		2,140
		Truck Sales & Services
				7,404
Other Industries: Total				63,905
Total Equities: 99.7% (Cost: $1,099,805)				1,384,914

See accompanying notes to financial statements.

48

Number of Shares or Principal Amount (000)			Value (000)
Securities Lending Collateral: 1.2%
	16,749,043	Dreyfus Government Cash Management Fund (e) (7 day yield of 0.000%)	$	16,749
Total Securities Lending Collateral: (Cost: $16,749)				16,749
Short-Term Obligation: 0.8%
		> Repurchase Agreement 0.8%
$	11,015	Repurchase Agreement with Fixed Income Clearing Corp., dated 12/31/09, due 1/04/10 at 0.00%, collateralized by a U.S. Treasury obligation, maturing 3/18/10, market value $11,239 (repurchase proceeds $11,015)		11,015
Total Short-Term Obligation: (Cost: $11,015)				11,015
Total Investments: 101.7% (Cost: $1,127,569)(f)				1,412,678
Obligation to Return Collateral for Securities Loaned: (1.2)%				(16,749	)
Cash and Other Assets Less Liabilities: (0.5)%				(6,320	)
Total Net Assets: 100.0%			$	1,389,609

ADR = American Depositary Receipts

See accompanying notes to financial statements.

49

Columbia Acorn USA

Statement of Investments, continued

> Notes to Statement of Investments (dollar values in thousands)

(a)  Non-income producing security.

(b)  All or a portion of this security was on loan at December 31, 2009. The total market value of Fund securities on loan at December 31, 2009 was $16,200.

(c)  An affiliated person of the Fund may include any company in which the Fund owns five percent or more of its outstanding voting shares. Holdings and transactions in these affiliated companies during the twelve months ended December 31, 2009, are as follows:

Affiliate	Balance of Shares Held 12/31/08		Purchases/ Additions		Sales/ Reductions		Balance of Shares Held 12/31/09		Value		Dividend
RCM Technologies		786,000		-		-		786,000	$	1,949	$	-
Cavco Industries		287,900		50,000		10,000		327,900		11,778		-
Total of Affiliated Transactions		1,073,900		50,000		10,000		1,113,900	$	13,727	$	-

  The aggregate cost and value of these companies at December 31, 2009, were $16,520 and $13,727, respectively. Investments in the affiliated companies represented 1.0% of total net assets at December 31, 2009.

(d)  Denotes a restricted security, which is subject to restrictions on resale under federal securities laws. These securities are valued at a fair value determined in good faith under consistently applied procedures established by the Board of Trustees. At December 31, 2009, the market value of these securities amounted to $34 which represented less than 0.01% of total net assets.

  Additional information on these securities is as follows:

Security	Acquisition Dates	Shares		Cost		Value
Metabolex, Series A	2/11/00		18,181	$	2,000	$	22
Medicure - Warrants	12/22/06		738,060		-		7
IsoRay - Warrants	3/21/07		100,000		-		2
Locus Pharmaceuticals, Series A-1, Pfd.	9/05/01		37,500		1,500		2
Locus Pharmaceuticals, Series B-1, Pfd.	2/08/07		19,329		56		1
				$	3,556	$	34

(e)  Investment made with cash collateral received from securities lending activity.

(f)  At December 31, 2009, for federal income tax purposes, the cost of investments was $1,127,912 and net unrealized appreciation was $284,766, consisting of gross unrealized appreciation of $457,844 and gross unrealized depreciation of $173,078.

  The following table summarizes the inputs used, as of December 31, 2009, in valuing the Fund's assets:

Investment Type	Quoted Prices (Level 1)		Other Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Equities
Information	$	491,584	$	-	$	-	$	491,584
Consumer Goods & Services		230,453		-		-		230,453
Industrial Goods & Services		184,106		-		-		184,106
Finance		174,267		-		-		174,267
Energy & Minerals		124,192		-		-		124,192
Health Care		116,373		9		25		116,407
Other Industries		63,905		-		-		63,905
Total Equities		1,384,880		9		25		1,384,914
Total Securities Lending Collateral		16,749		-		-		16,749
Short-Term Obligation		-		11,015		-		11,015
Total Investments	$	1,401,629	$	11,024	$	25	$	1,412,678

  The Fund's assets assigned to the Level 2 input category include certain foreign securities for which a third party statistical pricing service may be employed for purposes of fair market valuation.

See accompanying notes to financial statements.

50

> Notes to Statement of Investments (dollar values in thousands)

  The following table reconciles asset balances for the twelve-month period ending December 31, 2009, in which significant unobservable inputs (Level 3) were used in determining value:

Investments in Securities	Balance as of December 31, 2008		Accrued Discounts/ Premiums		Realized Gain/(Loss)		Change in Unrealized Appreciation (Depreciation)			Net Purchases (Sales)		Net Transfers into (out of) Level 3		Balance as of December 31, 2009
Equities
Health Care	$	41	$	-	$	-	$	(16	)	$	-	$	-	$	25
	$	41	$	-	$	-	$	(16	)	$	-	$	-	$	25

  The information in the above reconciliation table represents fiscal year to date activity for any securities identified as using Level 3 during the current fiscal period.

  The change in unrealized appreciation (depreciation) attributed to securities owned at December 31, 2009, which were valued using significant unobservable inputs (Level 3) amounted to $(16). This amount is included in net change in unrealized depreciation on the Statements of Changes in Net Assets.

  For more information on valuation inputs, and their aggregation into the levels used in the tables above, please refer to the Security Valuation section in the accompanying Notes to Financial Statements.

See accompanying notes to financial statements.

51

Columbia Acorn International Select

Major Portfolio Changes in the Fourth Quarter (Unaudited)

	Number of Shares
	09/30/09		12/31/09
Purchases
Europe
> United Kingdom
Cobham		2,115,000		2,650,000
Schroders		270,000		310,000
Spice Group		0		1,502,200
> Netherlands
Smit Internationale		0		38,285
> France
Eutelsat (France)		138,000		188,000
> Germany
Wirecard		0		635,000
> Spain
Red Electrica de Espana (Spain)		175,000		195,000
> Switzerland
Bank Sarasin & Cie		24,800		90,000
Asia
> Japan
Ain Pharmaciez		95,300		160,000
Nomura Holdings		0		560,000
> Singapore
Olam International (Singapore)		5,500,000		6,100,000
> China
Zhaojin Mining Industry (China)		0		3,711,000
Other Countries
> Australia
United Group		0		487,000

	Number of Shares
	09/30/09		12/31/09
Sales
Europe
> United Kingdom
RPS Group		1,200,000		0
> France
SES		210,000		0
> Germany
Wincor Nixdorf		110,000		0
Asia
> Japan
Aeon Mall		296,000		0
> Hong Kong
NagaCorp (Hong Kong)		9,918,766		3,867,066
Other Countries
> Canada
Potash Corp. of Saskatchewan		117,400		80,000
> United States
Alexion Pharmaceuticals		220,000		90,000
Cephalon		85,000		0
> Israel
Israel Chemicals		1,203,000		310,000

See accompanying notes to financial statements.

52

Columbia Acorn International Select

Statement of Investments, December 31, 2009

Number of Shares			Value (000)
				Equities: 93.3%
Europe 36.9%
		> United Kingdom 15.2%
	2,350,000	Serco	$	19,979
		Facilities Management
	1,100,000	Capita Group		13,268
		White Collar, Back Office Outsourcing
	2,650,000	Cobham		10,682
		Aerospace Components
	525,000	Intertek Group		10,571
		Testing, Inspection & Certification Services
	310,000	Schroders		6,617
		United Kingdom Top Tier Asset Manager
	1,502,200	Spice Group		1,466
		United Kingdom Utility Outsourcing
				62,583
		> Netherlands 6.0%
	169,162	Fugro		9,660
		Sub-sea Oilfield Services
	252,000	Imtech		6,763
		Electromechanical & ICT Installation & Maintenance
	41,000	Core Laboratories		4,843
		Oil & Gas Reservoir Consulting
	38,285	Smit Internationale		3,296
		Harbor & Offshore Towage & Marine Services
				24,562
		> France 4.3%
	89,500	Neopost		7,394
		Postage Meter Machines
	188,000	Eutelsat		6,032
		Fixed Satellite Services
	102,000	Zodiac Aerospace		4,257
		Leading Supplier to the Aerospace Industry
				17,683
		> Germany 3.2%
	635,000	Wirecard		8,730
		Online Payment Processing & Risk Management
	174,000	Rhoen-Klinikum		4,256
		Health Care Services
				12,986
		> Spain 2.6%
	195,000	Red Electrica de Espana		10,807
		Spanish Power Transmission
				10,807
		> Sweden 2.4%
	669,000	Hexagon		9,827
		Measurement Equipment
				9,827
		> Switzerland 1.7%
	35,700	Kuehne & Nagel		3,454
		Freight Forwarding/Logistics
	90,000	Bank Sarasin & Cie (a)		3,401
		Private Banking
				6,855

Number of Shares			Value (000)
		> Ireland 0.8%
	1,130,000	United Drug	$	3,448
		Irish Pharmaceutical Wholesaler & Outsourcer
				3,448
		> Denmark 0.7%
	29,000	Novozymes		3,007
		Industrial Enzymes
				3,007
Europe: Total				151,758
Asia 35.1%
		> Japan 14.6%
	1,277,000	Kansai Paint		10,603
		Paint Producer in Japan, India, China & Southeast Asia
	9,000	Jupiter Telecommunications		8,916
		Largest Cable Service Provider in Japan
	189,300	Benesse		7,916
		Education Service Provider
	634,300	Rohto Pharmaceutical		7,301
		Health & Beauty Products
	3,540	Seven Bank		7,031
		ATM Processing Services
	900	Orix JREIT		4,473
		Diversified REIT
	560,000	Nomura Holdings		4,127
		Brokerage, Dealing, Underwriting & Asset Management
	160,000	Ain Pharmaciez		3,839
		Dispensing Pharmacy/Drugstore Operator
	435,000	Kamigumi		3,161
		Port Cargo Handling & Logistics
	307,000	Suruga Bank		2,663
		Regional Bank
				60,030
		> Singapore 6.6%
	7,500,000	Ascendas REIT		11,745
		Singapore Industrial Property Landlord
	6,100,000	Olam International		11,424
		Agriculture Supply Chain Manager
	702,000	Singapore Exchange		4,138
		Singapore Equity & Derivatives Market Operator
				27,307
		> South Korea 6.6%
	73,100	NHN (a)		12,071
		South Korea's Largest Online Search Engine
	49,204	MegaStudy		10,082
		Online Education Service Provider
	151,000	Woongjin Coway		4,978
		South Korean Household Appliance Rental Service Provider
				27,131
		> China 4.7%
	3,711,000	Zhaojin Mining Industry		7,320
		Gold Mining & Refining in China
	6,731,000	Jiangsu Expressway		5,988
		Chinese Toll Road Operator

See accompanying notes to financial statements.

53

Columbia Acorn International Select

Statement of Investments, continued

Number of Shares			Value (000)
		> China—continued
	1,752,700	Shandong Weigao	$	5,821
		Vertically Integrated Hospital Consumable Manufacturer
				19,129
		> Hong Kong 2.6%
	434,700	Hong Kong Exchanges and Clearing		7,739
		Hong Kong Equity & Derivatives Market Operator
	1,259,800	Lifestyle International		2,337
		Mid to High-end Department Store Operator in Hong Kong & China
	3,867,066	NagaCorp		427
		Casino/Entertainment Complex in Cambodia
				10,503
Asia: Total				144,100
Other Countries 21.3%
		> Canada 7.9%
	701,250	Eldorado Gold (a)		10,004
		Gold Miner in Turkey, Greece, China & Brazil
	615,000	Pacific Rubiales Energy (a)		9,085
		Oil Production & Exploration in Colombia
	80,000	Potash Corp. of Saskatchewan		8,680
		World's Largest Producer of Potash
	172,000	CCL Industries		4,646
		Leading Global Label Manufacturer
				32,415
		> South Africa 6.2%
	630,000	Naspers		25,566
		Media in Africa & Other Emerging Markets
				25,566
		> United States 4.7%
	61,000	Diamond Offshore		6,004
		Offshore Drilling Contractor
	80,000	Oceaneering International (a)		4,681
		Provider of Sub-sea Services & Manufactured Products
	90,000	Alexion Pharmaceuticals (a)		4,394
		Biotech Focused on Orphan Diseases
	115,000	Atwood Oceanics (a)		4,123
		Offshore Drilling Contractor
				19,202
		> Australia 1.5%
	487,000	United Group		6,201
		Engineering & Facilities Management
				6,201
		> Israel 1.0%
	310,000	Israel Chemicals		4,048
		Producer of Potash, Phosphates, Bromine & Specialty Chemicals
				4,048
Other Countries: Total				87,432
Total Equities: 93.3% (Cost: $302,588)				383,290

Number of Shares or Principal Amount (000)			Value (000)
Exchange Traded Fund: 1.0%
	325,000	iShares MSCI Taiwan Index Fund	$	4,215
		Taiwan Exchange Traded Fund
Total Exchange Traded Fund: (Cost: $3,231)				4,215
Short-Term Obligations: 5.9%
		> Repurchase Agreement 5.4%
$	21,979	Repurchase Agreement with Fixed Income Clearing Corp., dated 12/31/09, due 1/04/10 at 0.00%, collateralized by a U.S. Treasury obligation, maturing 3/18/10, market value $22,423 (repurchase proceeds $21,979)		21,979
				21,979
		> Commercial Paper 0.5%
	2,000	Toyota Motor Credit 0.16% due 1/04/10		2,000
				2,000
Total Short-Term Obligations: (Amortized Cost: $23,979)				23,979
Total Investments: 100.2% (Cost: $329,798)(b)(c)				411,484
Cash and Other Assets Less Liabilities: (0.2)%				(809	)
Total Net Assets: 100.0%			$	410,675

See accompanying notes to financial statements.

54

> Notes to Statement of Investments (dollar values in thousands)

(a)  Non-income producing security.

(b)  At December 31, 2009, for federal income tax purposes, the cost of investments was $333,882 and net unrealized appreciation was $77,602, consisting of gross unrealized appreciation of $87,792 and gross unrealized depreciation of $10,190.

(c)  On December 31, 2009, the Fund's total investments were denominated in currencies as follows:

Currency	Value		Percentage of Net Assets
Euro	$	64,643		15.8
British Pound		62,583		15.2
U.S. Dollar		60,919		14.8
Japanese Yen		60,030		14.6
Hong Kong Dollar		29,632		7.2
Singapore Dollar		27,307		6.7
South Korean Won		27,131		6.6
South African Rand		25,566		6.2
Canadian Dollar		23,735		5.8
Other currencies less than 5% of total net assets		29,938		7.3
	$	411,484		100.2

  The following table summarizes the inputs used, as of December 31, 2009, in valuing the Fund's assets:

Investment Type	Quoted Prices (Level 1)		Other Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Equities
Europe	$	4,843	$	146,915	$	-	$	151,758
Asia		-		144,100		-		144,100
Other Countries		51,617		35,815		-		87,432
Total Equities		56,460		326,830		-		383,290
Total Exchange Traded Fund		4,215		-		-		4,215
Total Short-Term Obligations		-		23,979		-		23,979
Total Investments	$	60,675	$	350,809	$	-	$	411,484

  The Fund's assets assigned to the Level 2 input category include certain foreign securities for which a third party statistical pricing service may be employed for purposes of fair market valuation.

  For more information on valuation inputs, and their aggregation into the levels used in the table above, please refer to the Security Valuation section in the accompanying Notes to Financial Statements.

See accompanying notes to financial statements.

55

Columbia Acorn International Select

Portfolio Diversification

At December 31, 2009, the Fund's portfolio investments as a percent of net assets were diversified as follows:

	Value (000)		Percentage of Net Assets
> Industrial Goods & Services
Outsourcing Services	$	46,137		11.2
Other Industrial Services		31,246		7.6
Industrial Materials & Specialty Chemicals		17,658		4.3
Electrical Components		10,682		2.6
Machinery		7,394		1.8
		113,117		27.5
> Information
TV Broadcasting		25,566		6.2
Financial Processors		20,607		5.0
Internet Related		12,071		3.0
Instrumentation		9,827		2.4
CATV		8,916		2.2
Satellite Broadcasting & Services		6,032		1.5
		83,019		20.3
> Energy & Minerals
Mining		30,847		7.5
Oil Services		24,468		6.0
Oil & Gas Producers		9,085		2.2
		64,400		15.7
> Consumer Goods & Services
Other Consumer Services		25,313		6.2
Nondurables		11,947		2.9
Retail		3,839		0.9
Casinos & Gaming		427		0.1
		41,526		10.1
> Other Industries
Real Estate		16,218		4.0
Transportation		12,445		3.0
Regulated Utilities		10,807		2.6
		39,470		9.6
> Finance
Brokerage & Money Management		14,145		3.4
Banks		9,694		2.4
		23,839		5.8

	Value (000)			Percentage of Net Assets
> Health Care
Medical Equipment & Devices	$	10,215			2.5
Health Care Services		4,256			1.0
Pharmaceuticals		3,448			0.8
		17,919			4.3
Total Equities:		383,290			93.3
Exchange Traded Fund:		4,215			1.0
Short-Term Obligations:		23,979			5.9
Total Investments:		411,484			100.2
Cash and Other Assets Less Liabilities:		(809	)		(0.2	)
Net Assets:	$	410,675			100.0

See accompanying notes to financial statements.

56

Columbia Acorn Select

Major Portfolio Changes in the Fourth Quarter (Unaudited)

	Number of Shares
	09/30/09		12/31/09
Purchases
Consumer Goods & Services
Abercrombie & Fitch		750,000		1,650,000
GLG Life Tech (Canada)		0		108,000
ITT Educational Services		825,000		1,000,000
Safeway		3,500,000		3,600,000
Steelcase		2,612,994		3,000,000
Information
Globalstar		11,800,000		13,400,800
VisionChina Media - ADR (China)		4,121,817		4,250,000
WNS - ADR (India)		3,900,000		3,913,900
Energy & Minerals
Alange Energy (Colombia)		156,600		8,400,000
Houston American Energy		0		1,050,000
Cap-Link Ventures		0		17,144,000
Cap-Link Ventures-Warrants		0		17,144,000
Finance
Discover Financial Services		1,350,000		2,050,000
Industrial Goods & Services
Ametek		675,000		750,000

	Number of Shares
	09/30/09		12/31/09
Sales
Consumer Goods & Services
Career Education		1,300,000		977,000
Gap		575,000		0
Hertz		7,750,000		7,500,000
NagaCorp (Hong Kong)		76,000,000		29,633,051
SkillSoft - ADR		9,200,000		9,000,000
Information
American Tower		950,000		900,000
CardTronics		3,430,343		2,620,000
China Mass Media - ADR (China)		2,017,600		1,662,685
Discovery Communications, Series C		1,125,000		400,000
Hackett Group		1,334,442		1,000,000
Novell		8,100,000		7,000,000
Energy & Minerals
FMC Technologies		600,000		0
Synthesis Energy Systems (China)		2,500,000		2,200,000
Tetra Technologies		6,400,000		5,000,000
Uranium One (South Africa)		9,150,000		8,500,000
Finance
Conseco		14,900,000		13,500,000
MF Global		5,800,000		5,500,000
SEI Investments		1,250,000		1,100,000
Industrial Goods & Services
Donaldson		250,000		0
Expeditors International of Washington		850,000		600,000
Mobile Mini		750,000		117,328
Quanta Services		2,300,000		1,950,000

See accompanying notes to financial statements.

57

Columbia Acorn Select

Statement of Investments, December 31, 2009

Number of Shares			Value (000)
				Equities: 92.2%
Consumer Goods & Services 31.8%
		> Educational Services 11.2%
	1,000,000	ITT Educational Services (a)	$	95,960
		Post-secondary Degree Services
	9,000,000	SkillSoft - ADR (a)(b)		94,320
		Web-based Learning Solutions (E-Learning)
	977,000	Career Education (a)		22,774
		Post-secondary Education
	950,000	Princeton Review (a)		3,857
		College Preparation Courses
				216,911
		> Travel 8.0%
	7,500,000	Hertz (a)		89,400
		Largest U.S. Rental Car Operator
	2,600,000	Expedia (a)		66,846
		Online Travel Services Company
				156,246
		> Retail 6.9%
	3,600,000	Safeway		76,644
		Supermarkets
	1,650,000	Abercrombie & Fitch		57,502
		Teen Apparel Retailer
				134,146
		> Apparel 2.6%
	1,400,000	Coach		51,142
		Designer & Retailer of Branded Leather Accessories
				51,142
		> Casinos & Gaming 2.0%
	325,000,000	RexLot Holdings (China)		36,280
		Lottery Equipment Supplier in China
	29,633,051	NagaCorp (Hong Kong)		3,274
		Casino/Entertainment Complex in Cambodia
				39,554
		> Furniture & Textiles 1.0%
	3,000,000	Steelcase		19,080
		Office Furniture
				19,080
		> Food & Beverage 0.1%
	108,000	GLG Life Tech (Canada) (a)		826
		Produce an All-natural Sweetener Extracted from the Stevia Plant
	17,500,000	Fu Ji Food & Catering Services (China) (a)(c)		181
		Food Catering Service Provider in China
				1,007
Consumer Goods & Services: Total				618,086
Information 22.4%
		> Mobile Communications 6.6%
	1,550,000	Crown Castle International (a)		60,512
		Communications Towers
	900,000	American Tower (a)		38,889
		Communications Towers in USA & Latin America

Number of Shares			Value (000)
	505,000	SBA Communications (a)	$	17,251
		Communications Towers
	13,400,800	Globalstar (a)(b)(d)		11,659
		Satellite Mobile Voice & Data Carrier
				128,311
		> Contract Manufacturing 4.7%
	8,200,000	Sanmina-SCI (a)(b)		90,446
		Electronic Manufacturing Services
				90,446
		> Computer Services 3.2%
	3,913,900	WNS - ADR (India) (a)(b)(d)		58,904
		Offshore BPO (Business Process Outsourcing) Services
	1,000,000	Hackett Group (a)		2,780
		IT Integration & Best Practice Research
				61,684
		> Advertising 2.6%
	4,250,000	VisionChina Media - ADR (China) (a)(b)(d)		46,410
		Advertising on Digital Screens in China's Mass Transit System
	1,662,685	China Mass Media - ADR (China) (a)(b)(d)		4,290
		Media Planning Agency in China
				50,700
		> Computer Hardware & Related Equipment 1.8%
	750,000	Amphenol		34,635
		Electronic Connectors
				34,635
		> Business Software 1.5%
	7,000,000	Novell (a)		29,050
		Directory, Operating System & Identity Management Software
				29,050
		> Financial Processors 1.5%
	2,620,000	CardTronics (a)(b)		29,003
		Operates the World's Largest Network of ATMs
				29,003
		> CATV 0.5%
	400,000	Discovery Communications, Series C (a)		10,608
		CATV Programming
				10,608
Information: Total				434,437
Energy & Minerals 15.7%
		> Oil & Gas Producers 8.5%
	4,966,666	Pacific Rubiales Energy (Canada) (a)(e)		73,004
	1,483,334	Pacific Rubiales Energy (Canada) (a)		21,913
		Oil Production & Exploration in Colombia
	32,240,000	Canacol Energy (Canada) (a)(b)(e)		18,835
		Oil Producer in South America

See accompanying notes to financial statements.

58

Number of Shares			Value (000)
		> Oil & Gas Producers—continued
	2,500,000	Gran Tierra Energy (Canada) (a)	$	14,342
		Oil Exploration & Production in Colombia, Peru & Argentina
	17,144,000	Cap-Link Ventures (a)(e)		7,213
	17,144,000	Cap-Link Ventures-Warrants (a)(e)		4,590
		Oil & Gas Exploration & Production in Colombia, Peru & Paraguay
	25,883,000	ShaMaran Petroleum (Canada) (a)(b)(e)		10,691
	5,117,000	ShaMaran Petroleum (Canada) (a)(b)		2,202
		Oil Exploration in Kurdistan
	1,050,000	Houston American Energy		6,468
		Oil & Gas Exploration/Production in Colombia
	8,400,000	Alange Energy (Colombia) (a)		5,060
		Oil & Gas Exploration/Production in Colombia
				164,318
		> Alternative Energy 3.1%
	1,900,000	Canadian Solar (China) (a)(d)		54,758
		Solar Cell & Module Manufacturer
	1,400,000	Real Goods Solar (a)(b)		4,410
		Residential Solar Energy Installer
	2,200,000	Synthesis Energy Systems (China) (a)		2,041
		Owner/Operator of Gasification Plants
				61,209
		> Oil Services 2.8%
	5,000,000	Tetra Technologies (a)(b)		55,400
		U.S.-based Services Company with Life of Field Approach
				55,400
		> Mining 1.3%
	8,500,000	Uranium One (South Africa) (a)		24,545
		Uranium Mines in Kazakhstan, the U.S. & Australia
				24,545
Energy & Minerals: Total				305,472
Finance 10.0%
		> Brokerage & Money Management 5.0%
	1,300,000	Eaton Vance		39,533
		Specialty Mutual Funds
	5,500,000	MF Global (a)		38,225
		Futures Broker
	1,100,000	SEI Investments		19,272
		Mutual Fund Administration & Investment Management
				97,030
		> Insurance 3.5%
	13,500,000	Conseco (a)(b)		67,500
		Life, Long-term Care & Medical Supplement Insurance
				67,500

Number of Shares			Value (000)
		> Credit Cards 1.5%
	2,050,000	Discover Financial Services	$	30,156
		Credit Card Company
				30,156
Finance: Total				194,686
Industrial Goods & Services 9.1%
		> Waste Management 2.6%
	1,500,000	Waste Management		50,715
		U.S. Garbage Collection & Disposal
				50,715
		> Outsourcing Services 2.1%
	1,950,000	Quanta Services (a)		40,638
		Electrical & Telecom Construction Services
				40,638
		> Machinery 1.5%
	750,000	Ametek		28,680
		Aerospace/Industrial Instruments
				28,680
		> Industrial Materials & Specialty Chemicals 1.3%
	1,000,000	Nalco Holding Company		25,510
		Provider of Water Treatment & Process Chemicals & Services
	18,263	ChemSpec International - ADR (China) (a)		120
		Specialty Chemicals with Focus on Fluorinated Chemical Manufacturing
				25,630
		> Other Industrial Services 1.2%
	600,000	Expeditors International of Washington		20,838
		International Freight Forwarder
	117,328	Mobile Mini (a)		1,653
		Portable Storage Units Leasing
				22,491
		> Industrial Distribution 0.4%
	90,000	WW Grainger		8,715
		Industrial Distribution
				8,715
Industrial Goods & Services: Total				176,869
Other Industries 3.2%
		> Transportation 3.2%
	1,300,000	JB Hunt Transport Services		41,951
		Truck & Intermodal Carrier
	1,125,000	American Commercial Lines (a)(b)		20,621
		Operator of Inland Barges/Builder of Barges & Vessels
				62,572
Other Industries: Total				62,572

See accompanying notes to financial statements.

59

Columbia Acorn Select

Statement of Investments, continued

Number of Shares or Principal Amount (000)			Value (000)
Health Care —%
		> Health Care Services —%
	27,500	Emdeon (a)	$	419
		Revenue & Payment Cycle Management
				419
Health Care: Total				419
Total Equities: 92.2% (Cost: $1,551,056)				1,792,541
Securities Lending Collateral: 0.2%
	3,884,667	Dreyfus Government Cash Management Fund (7 day yield of 0.000%) (f)		3,885
Total Securities Lending Collateral: (Cost: $3,885)				3,885
Short-Term Obligations: 8.0%
		> Repurchase Agreement 7.5%
$	146,852	Repurchase Agreement with Fixed Income Clearing Corp., dated 12/31/09, due 1/04/10 at 0.00%, collateralized by a U.S. Treasury obligation, maturing 4/01/10, market value $149,790 (repurchase proceeds $146,852)		146,852
				146,852
		> Commercial Paper 0.5%
	9,300	Toyota Motor Credit 0.16% due 1/04/10		9,300
				9,300
Total Short-Term Obligations: (Amortized Cost: $156,152)				156,152
Total Investments: 100.4% (Cost: $1,711,093)(g)				1,952,578
Obligation to Return Collateral for Securities Loaned: (0.2)%				(3,885	)
Cash and Other Assets Less Liabilities: (0.2)%				(3,848	)
Total Net Assets: 100.0%			$	1,944,845

ADR = American Depositary Receipts.

See accompanying notes to financial statements.

60

> Notes to Statement of Investments (dollar values in thousands)

(a)  Non-income producing security.

(b)  An affiliated person of the Fund may include any company in which the Fund owns five percent or more of its outstanding voting shares. Holdings and transactions in affiliated companies during the twelve months ended December 31, 2009, are as follows:

Affiliates	Balance of Shares Held 12/31/08		Purchases/ Additions		Sales/ Reductions			Balance of Shares Held 12/31/09		Value		Dividend
American Commercial Lines		3,803,849		696,151		3,375,000	**		1,125,000	$	20,621	$	-
Canacol Energy		-		32,240,000		-			32,240,000		18,835
Canadian Solar*		1,825,000		400,000		325,000			1,900,000		54,758		-
CardTronics		3,560,000		140,000		1,080,000			2,620,000		29,003		-
China Mass Media - ADR		2,350,000		-		687,315			1,662,685		4,290		-
Conseco		14,950,000		-		1,450,000			13,500,000		67,500		-
Globalstar		10,000,000		4,600,800		1,200,000			13,400,800		11,659		-
Real Goods Solar		1,500,000		-		100,000			1,400,000		4,410		-
Sanmina-SCI		50,200,000		-		42,000,000	***		8,200,000		90,446		-
ShaMaran Petroleum		-		31,000,000		-			31,000,000		12,893
SkillSoft - ADR		9,500,000		-		500,000			9,000,000		94,320		-
Synthesis Energy Systems*		2,800,000		-		600,000			2,200,000		2,041		-
Tetra Technologies		6,150,000		1,050,000		2,200,000			5,000,000		55,400		-
VisionChina Media - ADR		3,118,900		1,131,100		-			4,250,000		46,410
WNS - ADR		3,100,000		859,975		46,075			3,913,900		58,904		-
Total of Affiliated Transactions		112,857,749		72,118,026		53,563,390			131,412,385	$	571,490	$	-

*  At December 31, 2009, the Fund owned less than five percent of the company's outstanding voting shares.

**  Includes the effect of a 1:4 reverse stock split.

***  Includes the effect of a 1:6 reverse stock split.

  The aggregate cost and value of these companies at December 31, 2009, were $705,100 and $571,490, respectively. Investments in affiliated companies represented 29.4% of total net assets at December 31, 2009.

(c)  Illiquid security.

(d)  All or a portion of this security was on loan at December 31, 2009. The total market value of Fund securities on loan at December 31, 2009 was $3,749.

(e)  Denotes a restricted security, which is subject to restrictions on resale under federal securities laws. These securities are valued at a fair value determined in good faith under consistently applied procedures established by the Board of Trustees. At December 31, 2009, the market value of these securities amounted to $114,333, which represented 5.88% of total net assets.

  Additional information on these securities is as follows:

Security	Acquisition Dates	Shares		Cost		Value
Canacol Energy	9/23/09		32,240,000	$	8,397	$	18,835
Pacific Rubiales Energy	7/12/07		4,966,666		19,942		73,004
Cap-Link Ventures	11/20/09		17,144,000		3,499		7,213
Cap-Link Ventures-Warrants	11/20/09		17,144,000		2,226		4,590
ShaMaran Petroleum	9/15/09		25,883,000		18,117		10,691
				$	52,181	$	114,333

(f)  Investment made with cash collateral received from securities lending activity.

(g)  At December 31, 2009, for federal income tax purposes, the cost of investments was $1,729,836 and net unrealized appreciation was $222,742, consisting of gross unrealized appreciation of $585,007 and gross unrealized depreciation of $362,265.

See accompanying notes to financial statements.

61

Columbia Acorn Select

Statement of Investments, continued

> Notes to Statement of Investments (dollar values in thousands)

  The following table summarizes the inputs used, as of December 31, 2009, in valuing the Fund's assets:

Investment Type	Quoted Prices (Level 1)		Other Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Equities
Consumer Goods & Services	$	578,351	$	39,554	$	181	$	618,086
Information		434,437		-		-		434,437
Energy & Minerals		191,139		114,333		-		305,472
Finance		194,686		-		-		194,686
Industrial Goods & Services		176,869		-		-		176,869
Other Industries		62,572		-		-		62,572
Health Care		419		-		-		419
Total Equities		1,638,473		153,887		181		1,792,541
Total Securities Lending Collateral		3,885		-		-		3,885
Total Short-Term Obligations		-		156,152		-		156,152
Total Investments	$	1,642,358	$	310,039	$	181	$	1,952,578

  The Fund's assets assigned to the Level 2 input category include certain foreign securities for which a third party statistical pricing service may be employed for purposes of fair market valuation.

  The following table reconciles asset balances for the twelve-month period ending December 31, 2009, in which significant unobservable inputs (Level 3) were used in determining value:

Investments in Securities	Balance as of December 31, 2008		Accrued Discounts/ Premiums		Realized Gain/(Loss)		Change in Unrealized Appreciation (Depreciation)			Net Purchases (Sales)		Net Transfers into (out of) Level 3		Balance as of December 31, 2009
Equities
Consumer Goods & Services	$	-	$	-	$	-	$	(14,925	)	$	-	$	15,106	$	181
	$	-	$	-	$	-	$	(14,925	)	$	-	$	15,106	$	181

  The information in the above reconciliation table represents fiscal year to date activity for any securities identified as using Level 3 inputs during the current fiscal period.

  The change in unrealized appreciation (depreciation) attributed to securities owned at December 31, 2009, which were valued using significant unobservable inputs (Level 3) amounted to $(14,925). This amount is included in net change in unrealized depreciation on the Statements of Changes in Net Assets.

  For more information on valuation inputs, and their aggregation into the levels used in the tables above, please refer to the Security Valuation section in the accompanying Notes to Financial Statements.

See accompanying notes to financial statements.

62

Columbia Thermostat Fund

Statement of Investments, December 31, 2009

Number of Shares or Principal Amount (000)			Value (000)
		> Stock Funds: 85.0%
	2,728,249	Columbia Large Cap Enhanced Core Fund, Class Z	$	29,383
	1,982,660	Columbia Dividend Income Fund, Class Z		23,495
	720,997	Columbia Acorn Fund, Class Z		17,794
	1,018,204	Columbia Marsico Growth Fund, Class Z		17,605
	513,283	Columbia Acorn International, Class Z		17,585
	510,373	Columbia Acorn Select, Class Z		11,932
Total Stock Funds (Cost: $119,130)				117,794
		> Bond Funds: 14.5%
	1,148,436	Columbia Intermediate Bond Fund, Class Z		10,095
	535,341	Columbia U.S. Treasury Index Fund, Class Z		5,932
	551,500	Columbia Conservative High Yield Fund, Class Z		4,125
Total Bond Funds (Cost: $19,764)				20,152
Short-Term Obligation: 0.6%
		> Repurchase Agreement: 0.6%
$	787	Repurchase Agreement with Fixed Income Clearing Corp., dated 12/31/09, due 1/04/10 at 0.00%, collateralized by a U.S. Government Agency obligation, maturing 9/17/10, market value $806 (repurchase proceeds $787)		787
Total Short-Term Obligation (Cost: $787)				787
Total Investments: 100.1% (Cost: $139,681)(a)				138,733
Cash and Other Assets Less Liabilities: (0.1)%				(144	)
Total Net Assets: 100.0%			$	138,589

See accompanying notes to financial statements.

63

Columbia Thermostat Fund

Statement of Investments, continued

> Notes to Statement of Investments (dollar values in thousands)

(a)  At December 31, 2009, for federal income tax purposes, the cost of investments was $140,157 and net unrealized depreciation was $1,424, consisting of gross unrealized appreciation of $8,876 and gross unrealized depreciation of $10,300.

  The following table summarizes the inputs used, as of December 31, 2009, in valuing the Fund's assets:

Investment Type	Quoted Prices (Level 1)		Other Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Total Stock Funds	$	117,794	$	-	$	-	$	117,794
Total Bond Funds		20,152		-		-		20,152
Total Short-Term Obligation		-		787		-		787
Total Investments	$	137,946	$	787	$	-	$	138,733

  For more information on valuation inputs, and their aggregation into the levels used in the table above, please refer to the Security Valuation section in the accompanying Notes to Financial Statements.

See accompanying notes to financial statements.

64

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65

Columbia Acorn Family of Funds

Statements of Assets and Liabilities

December 31, 2009	Columbia Acorn Fund			Columbia Acorn International			Columbia Acorn USA
(in thousands)
Assets:
Unaffiliated investments, at cost	$	7,848,115		$	3,281,798		$	1,111,049
Affiliated investments, at cost (See Note 4)		3,167,879			77,410			16,520
Unaffiliated investments, at value (including securities on loan: Columbia Acorn Fund $175,896; Columbia Acorn International $25,743; Columbia Acorn USA $16,200; Columbia Acorn International Select $–; Columbia Acorn Select $3,749; Columbia Thermostat Fund $–)	$	11,210,831		$	4,300,923		$	1,398,951
Affiliated investments, at value (See Note 4)		3,750,852			114,524			13,727
Cash		34			—			—	*
Foreign currency (cost: Columbia Acorn Fund $3,308; Columbia Acorn International $29,329; Columbia Acorn International Select $25; Columbia Acorn Select $113)		3,453			29,594			—
Net unrealized appreciation on forward foreign currency exchange contracts		—			6,689			—
Receivable for:
Investments sold		19,206			8,744			6,072
Fund shares sold		14,294			8,161			604
Dividends and interest		7,667			4,939			649
Securities lending income		89			27			10
Foreign tax reclaims		166			1,030			—
Trustees' Deferred Compensation Investments		3,145			876			244
Other assets		92			25			8
Total Assets		15,009,829			4,475,532			1,420,265
Liabilities:
Payable to custodian bank		—			9			—
Collateral on securities loaned		183,434			26,644			16,749
Expense reimbursement due to Advisor		—			—			—
Net unrealized depreciation on forward foreign currency exchange contracts		—			4,205			—
Payable for:
Investments purchased		44,749			4,766			1,144
Fund shares redeemed		37,841			2,725			11,007
Management fee		7,895			2,855			999
Administration fee		502			152			47
12b-1 Service & Distribution fees		1,567			217			78
Reports to shareholders		785			327			108
Deferred Trustees' fees		3,145			876			244
Transfer agent fees		2,095			405			230
Trustees' fees		—	*		—	*		2
Custody fees		181			289			5
Chief compliance officer expenses		27			8			2
Foreign capital gains tax		200			1,217			—
Other liabilities		257			99			41
Total Liabilities		282,678			44,794			30,656
Net Assets	$	14,727,151		$	4,430,738		$	1,389,609
Composition of Net Assets:
Paid in capital	$	11,247,302		$	3,962,215		$	1,228,860
Undistributed/(overdistributed) net investment income (Accumulated net investment loss)		(20,794	)		39,113			(275	)
Accumulated net realized gain/(loss)		(444,982	)		(628,257	)		(124,085	)
Net unrealized appreciation/(depreciation) on:
Investments		3,945,689			1,056,239			285,109
Foreign capital gains tax		(200	)		(1,217	)		—
Foreign currency translations		136			2,645			—
Net Assets	$	14,727,151		$	4,430,738		$	1,389,609
Net asset value per share – Class A (a)	$	23.98		$	34.13		$	22.43
(Net assets/shares)		($2,937,761/122,497)			($578,599/16,955)			($178,605/7,962)
Maximum offering price per share – Class A (b)	$	25.44		$	36.21		$	23.80
(Net asset value per share/front- end sales charge)		($23.98/0.9425)			($34.13/0.9425)			($22.43/0.9425)
Net asset value and offering price per share – Class B (a)	$	22.43		$	33.22		$	20.99
(Net assets/shares)		($525,072/23,411)			($38,835/1,169)			($20,903/996)
Net asset value and offering price per share – Class C (a)	$	22.23		$	33.08		$	20.84
(Net assets/shares)		($736,818/33,142)			($85,625/2,588)			($32,508/1,560)
Net asset value and offering price per share – Class Z (c)	$	24.68		$	34.26		$	23.19
(Net assets/shares)		($10,527,500/426,515)			($3,727,679/108,818)			($1,157,593/49,909)

December 31, 2009	Columbia Acorn International Select			Columbia Acorn Select			Columbia Thermostat Fund
(in thousands)
Assets:
Unaffiliated investments, at cost	$	329,798		$	1,005,993		$	787
Affiliated investments, at cost (See Note 4)		—			705,100			138,894
Unaffiliated investments, at value (including securities on loan: Columbia Acorn Fund $175,896; Columbia Acorn International $25,743; Columbia Acorn USA $16,200; Columbia Acorn International Select $–; Columbia Acorn Select $3,749; Columbia Thermostat Fund $–)	$	411,484		$	1,381,088		$	787
Affiliated investments, at value (See Note 4)		—			571,490			137,946
Cash		—			—			1
Foreign currency (cost: Columbia Acorn Fund $3,308; Columbia Acorn International $29,329; Columbia Acorn International Select $25; Columbia Acorn Select $113)		25			113			—
Net unrealized appreciation on forward foreign currency exchange contracts		—			—			—
Receivable for:
Investments sold		5			178			273
Fund shares sold		769			2,479			93
Dividends and interest		368			892			—
Securities lending income		—			4			—
Foreign tax reclaims		16			—			—
Trustees' Deferred Compensation Investments		—			288			—
Other assets		3			11			1
Total Assets		412,670			1,956,543			139,101
Liabilities:
Payable to custodian bank		—	*		4			—
Collateral on securities loaned		—			3,885			—
Expense reimbursement due to Advisor		—	*		—			6
Net unrealized depreciation on forward foreign currency exchange contracts		—			—			—
Payable for:
Investments purchased		189			48			—
Fund shares redeemed		1,259			5,221			327
Management fee		327			1,321			12
Administration fee		14			66			5
12b-1 Service & Distribution fees		25			242			48
Reports to shareholders		46			191			41
Deferred Trustees' fees		44			288			28
Transfer agent fees		37			329			30
Trustees' fees		—	*		—	*		—	*
Custody fees		22			50			—
Chief compliance officer expenses		1			4			—	*
Foreign capital gains tax		—			—			—
Other liabilities		31			49			15
Total Liabilities		1,995			11,698			512
Net Assets	$	410,675		$	1,944,845		$	138,589
Composition of Net Assets:
Paid in capital	$	405,974		$	1,850,202		$	166,320
Undistributed/(overdistributed) net investment income (Accumulated net investment loss)		1,978			(8,359	)		1,247
Accumulated net realized gain/(loss)		(78,954	)		(138,483	)		(28,030	)
Net unrealized appreciation/(depreciation) on:
Investments		81,686			241,485			(948	)
Foreign capital gains tax		—			—			—
Foreign currency translations		(9	)		—	*		—
Net Assets	$	410,675		$	1,944,845		$	138,589
Net asset value per share – Class A (a)	$	23.39		$	22.81		$	10.90
(Net assets/shares)		($64,664/2,764)			($522,443/22,908)			($42,976/3,943)
Maximum offering price per share – Class A (b)	$	24.82		$	24.20		$	11.56
(Net asset value per share/front- end sales charge)		($23.39/0.9425)			($22.81/0.9425)			($10.90/0.9425)
Net asset value and offering price per share – Class B (a)	$	22.34		$	21.41		$	10.93
(Net assets/shares)		($3,887/174)			($88,004/4,111)			($32,758/2,997)
Net asset value and offering price per share – Class C (a)	$	22.21		$	21.25		$	10.91
(Net assets/shares)		($11,096/500)			($93,121/4,382)			($21,090/1,933)
Net asset value and offering price per share – Class Z (c)	$	23.64		$	23.38		$	10.80
(Net assets/shares)		($331,028/14,003)			($1,241,277/53,093)			($41,765/3,866)

(a)  Redemption price per share is equal to net asset value less any applicable contingent deferred sales charge and redemption fee.

(b)  On sales of $50,000 or more the offering price is reduced.

(c)  Redemption price per share is equal to net asset value less any applicable redemption fee.

*  Rounds to less than $500.

See accompanying notes to financial statements.

66

Columbia Acorn Family of Funds

Statements of Operations
For the Year Ended December 31, 2009

(in thousands)	Columbia Acorn Fund			Columbia Acorn International			Columbia Acorn USA
Investment Income:
Dividend income	$	97,974		$	78,907		$	7,290
Dividend income from affiliates (See Note 4)		17,346			3,000			—
Dividends from affiliated investment company shares (See Note 4)		—			—			—
Interest income		459			149			23
Securitites lending income		957			174			139
		116,736			82,230			7,452
Foreign taxes withheld		(1,865	)		(6,487	)		(5	)
Total Investment Income		114,871			75,743			7,447
Expenses:
Management fee		77,909			26,444			9,677
Administration fee		5,179			1,459			477
12b-1 Service and Distribution fees:
Class A		6,042			1,076			372
Class B		3,969			279			162
Class C		6,373			676			269
Transfer agent fees:
Class A		1,927			681			135
Class B		1,309			122			62
Class C		950			149			39
Class Z		2,857			1,241			446
Custody fees		921			2,572			51
Trustees' fees		922			260			85
Reports to shareholders		2,065			909			328
Chief compliance officer expenses (See Note 4)		525			142			48
Other expenses		1,431			504			223
Total expenses		112,379			36,514			12,374
Less custody fees paid indirectly		—	*		—	*		—	*
Less reimbursement of expenses by Investment Advisor		—			—			—
Net Expenses		112,379			36,514			12,374
Net Investment Income/(Loss)		2,492			39,229			(4,927	)
Net Realized and Unrealized Gain (Loss) on Portfolio Positions:
Net realized gain/(loss) on:
Unaffiliated investments		(227,130	)		(248,697	)		(20,041	)
Affiliated investments (See Note 4)		(100,539	)		(3,829	)		(110	)
Foreign currency transactions and forward foreign currency   exchange contracts		(229	)		4,140			—
Foreign capital gains tax		—			(1,789	)		—
Distributions from affiliated investment company shares		—			—			—
Net realized loss		(327,898	)		(250,175	)		(20,151	)
Net change in net unrealized appreciation/(depreciation) on:
Unaffiliated investments		3,343,556			1,554,069			437,114
Affiliated investments (See Note 4)		1,143,521			49,345			1,994
Foreign currency translations and forward foreign currency   exchange contracts		134			6,043			—
Foreign capital gains tax		(200	)		(1,217	)		—
Net change in unrealized appreciation/ (depreciation)		4,487,011			1,608,240			439,108
Net realized and unrealized gain		4,159,113			1,358,065			418,957
Net Increase in Net Assets resulting from Operations	$	4,161,605		$	1,397,294		$	414,030

(in thousands)	Columbia Acorn International Select			Columbia Acorn Select			Columbia Thermostat Fund
Investment Income:
Dividend income	$	7,141		$	7,661		$	—
Dividend income from affiliates (See Note 4)		—			—			—
Dividends from affiliated investment company shares (See Note 4)		—			—			2,149
Interest income		16			68			—	*
Securitites lending income		1			282			—
		7,158			8,011			2,149
Foreign taxes withheld		(521	)		—			—
Total Investment Income		6,637			8,011			2,149
Expenses:
Management fee		3,039			12,761			128
Administration fee		138			666			55
12b-1 Service and Distribution fees:
Class A		137			1,086			99
Class B		29			581			245
Class C		98			769			204
Transfer agent fees:
Class A		81			434			77
Class B		15			241			77
Class C		25			147			44
Class Z		87			446			17
Custody fees		213			297			—
Trustees' fees		34			119			17
Reports to shareholders		167			478			121
Chief compliance officer expenses (See Note 4)		13			66			5
Other expenses		168			292			106
Total expenses		4,244			18,383			1,195
Less custody fees paid indirectly		—	*		—	*		—	*
Less reimbursement of expenses by Investment Advisor		(5	)		—			(327	)
Net Expenses		4,239			18,383			868
Net Investment Income/(Loss)		2,398			(10,372	)		1,281
Net Realized and Unrealized Gain (Loss) on Portfolio Positions:
Net realized gain/(loss) on:
Unaffiliated investments		(31,361	)		31,100			—
Affiliated investments (See Note 4)		—			(71,935	)		(18,232	)
Foreign currency transactions and forward foreign currency   exchange contracts		(46	)		589			—
Foreign capital gains tax		—			—			—
Distributions from affiliated investment company shares		—			—			1
Net realized loss		(31,407	)		(40,246	)		(18,231	)
Net change in net unrealized appreciation/(depreciation) on:
Unaffiliated investments		127,658			521,773			—
Affiliated investments (See Note 4)		—			316,510			51,494
Foreign currency translations and forward foreign currency   exchange contracts		(25	)		(3	)		—
Foreign capital gains tax		—			—			—
Net change in unrealized appreciation/ (depreciation)		127,633			838,280			51,494
Net realized and unrealized gain		96,226			798,034			33,263
Net Increase in Net Assets resulting from Operations	$	98,624		$	787,662		$	34,544

*  Rounds to less than $500.

See accompanying notes to financial statements.

67

Columbia Acorn Family of Funds

Statements of Changes in Net Assets

	Columbia Acorn Fund						Columbia Acorn International						Columbia Acorn USA
Increase (Decrease) in Net Assets	Year ended December 31,						Year ended December 31,						Year ended December 31,
(in thousands)	2009			2008 (a)			2009			2008 (a)			2009			2008 (a)
Operations:
Net investment income/(loss)	$	2,492		$	12,367		$	39,229		$	76,400		$	(4,927	)	$	(5,465	)
Net realized gain/(loss) on investments, foreign currency transactions, forward foreign currency exchange contracts and foreign capital gains tax		(227,359	)		234,120			(246,346	)		(283,342	)		(20,041	)		(102,173	)
Net realized gain/(loss) on affiliated investments and distributions from affiliated investment companies and affiliated investment company shares		(100,539	)		(245,832	)		(3,829	)		(95,523	)		(110	)		—
Net change in net unrealized appreciation/(depreciation) on investments, foreign currency translations, forward foreign currency exchange contracts and foreign capital gains tax		3,343,490			(5,424,645	)		1,558,895			(2,403,427	)		437,114			(492,195	)
Net change in net unrealized appreciation/(depreciation) on affiliated investment companies and affiliated investment company shares		1,143,521			(1,918,721	)		49,345			337			1,994			(3,773	)
Net Increase/(Decrease) from Operations		4,161,605			(7,342,711	)		1,397,294			(2,705,555	)		414,030			(603,606	)
Distributions to Shareholders From:
Net investment income – Class A		—			—			(6,102	)		(1,020	)		—			—
Net realized gain – Class A		—			(91,100	)		—			(9,807	)		—			(8,248	)
Net investment income – Class B		—			—			(290	)		—	*		—			—
Net realized gain – Class B		—			(26,893	)		—			(1,332	)		—			(1,748	)
Net investment income – Class C		—			—			(348	)		—	*		—			—
Net realized gain – Class C		—			(28,315	)		—			(2,146	)		—			(1,740	)
Net investment income – Class Z		(20,981	)		(6,088	)		(53,467	)		(23,593	)		—			—
Net realized gain – Class Z		—			(284,695	)		—			(68,973	)		—			(41,787	)
Total Distributions to Shareholders		(20,981	)		(437,091	)		(60,207	)		(106,871	)		—			(53,523	)
Share Transactions:
Subscriptions – Class A		639,685			612,669			181,444			277,346			54,531			53,928
Distributions reinvested – Class A		—			83,711			5,737			9,979			—			7,538
Redemptions – Class A		(744,769	)		(1,151,023	)		(140,626	)		(207,715	)		(66,724	)		(69,749	)
Net Increase/(Decrease) – Class A		(105,084	)		(454,643	)		46,555			79,610			(12,193	)		(8,283	)
Subscriptions – Class B		100			1,991			14			1,704			5			71
Distributions reinvested – Class B		—			24,675			264			1,209			—			1,615
Redemptions – Class B		(224,032	)		(255,304	)		(14,833	)		(23,974	)		(9,892	)		(11,765	)
Net Decrease – Class B		(223,932	)		(228,638	)		(14,555	)		(21,061	)		(9,887	)		(10,079	)
Subscriptions – Class C		58,069			62,517			14,494			20,234			2,513			3,931
Distributions reinvested – Class C		—			22,379			265			1,596			—			1,523
Redemptions – Class C		(151,419	)		(287,537	)		(18,021	)		(43,103	)		(5,210	)		(10,090	)
Net Increase/(Decrease) – Class C		(93,350	)		(202,641	)		(3,262	)		(21,273	)		(2,697	)		(4,636	)
Subscriptions – Class Z		1,484,719			1,526,416			671,256			664,727			246,578			213,395
Distributions reinvested – Class Z		17,690			251,789			38,426			64,910			—			37,687
Redemptions – Class Z		(1,364,770	)		(2,162,613	)		(486,805	)		(912,602	)		(190,623	)		(190,501	)
Net Increase/(Decrease) – Class Z		137,639			(384,408	)		222,877			(182,965	)		55,955			60,581
Net Increase/(Decrease) from Share Transactions		(284,727	)		(1,270,330	)		251,615			(145,689	)		31,178			37,583
Redemption Fees		—			—			259			354			—			—
Increase from regulatory settlements (See Note 9)		40			—			1,210			—			5			—
Total Increase/(Decrease) in Net Assets		3,855,937			(9,050,132	)		1,590,171			(2,957,761	)		445,213			(619,546	)
Net Assets:
Beginning of period		10,871,214			19,921,346			2,840,567			5,798,328			944,396			1,563,942
End of period	$	14,727,151		$	10,871,214		$	4,430,738		$	2,840,567		$	1,389,609		$	944,396
Undistributed/(Overdistributed) Net Investment Income or (Accumulated Net Investment Loss)	$	(20,794	)	$	(2,116	)	$	39,113		$	57,491		$	(275	)	$	(157	)

(a)  Certain items in the prior year financial statements were reclassified to conform to the current year's presentation. Such reclassifications had no effect on net income or net assets.

*  Rounds to less than $500.

See accompanying notes to financial statements.

68

	Columbia Acorn International Select						Columbia Acorn Select						Columbia Thermostat Fund
Increase (Decrease) in Net Assets	Year ended December 31,						Year ended December 31,						Year ended December 31,
(in thousands)	2009			2008			2009			2008 (a)			2009			2008
Operations:
Net investment income/(loss)	$	2,398		$	2,451		$	(10,372	)	$	(17,307	)	$	1,281		$	3,146
Net realized gain/(loss) on investments, foreign currency transactions, forward foreign currency exchange contracts and foreign capital gains tax		(31,407	)		(46,780	)		31,689			(71,830	)		—			—
Net realized gain/(loss) on affiliated investments and distributions from affiliated investment companies and affiliated investment company shares		—			—			(71,935	)		(15,794	)		(18,231	)		(9,015	)
Net change in net unrealized appreciation/(depreciation) on investments, foreign currency translations, forward foreign currency exchange contracts and foreign capital gains tax		127,633			(101,043	)		521,770			(965,213	)		—			—
Net change in net unrealized appreciation/(depreciation) on affiliated investment companies and affiliated investment company shares		—			—			316,510			(365,076	)		51,494			(58,979	)
Net Increase/(Decrease) from Operations		98,624			(145,372	)		787,662			(1,435,220	)		34,544			(64,848	)
Distributions to Shareholders From:
Net investment income – Class A		(456	)		—			—			—			(7	)		(1,051	)
Net realized gain – Class A		—			(984	)		—			(25,410	)		—			(337	)
Net investment income – Class B		—			—			—			—			—			(657	)
Net realized gain – Class B		—			(189	)		—			(4,641	)		—			(371	)
Net investment income – Class C		—			—			—			—			—			(361	)
Net realized gain – Class C		—			(288	)		—			(4,551	)		—			(201	)
Net investment income – Class Z		(3,077	)		(280	)		—			—			(115	)		(1,140	)
Net realized gain – Class Z		—			(3,600	)		—			(39,523	)		—			(301	)
Total Distributions to Shareholders		(3,533	)		(5,341	)		—			(74,125	)		(122	)		(4,419	)
Share Transactions:
Subscriptions – Class A		30,670			47,637			98,691			131,376			5,619			21,460
Distributions reinvested – Class A		439			901			—			23,381			6			1,269
Redemptions – Class A		(28,558	)		(21,936	)		(190,444	)		(377,780	)		(14,381	)		(14,939	)
Net Increase/(Decrease) – Class A		2,551			26,602			(91,753	)		(223,023	)		(8,756	)		7,790
Subscriptions – Class B		—			271			39			388			—			2,089
Distributions reinvested – Class B		—			170			—			4,147			—			943
Redemptions – Class B		(1,493	)		(3,345	)		(23,638	)		(41,288	)		(12,541	)		(14,056	)
Net Decrease – Class B		(1,493	)		(2,904	)		(23,599	)		(36,753	)		(12,541	)		(11,024	)
Subscriptions – Class C		1,872			7,847			6,147			8,177			1,960			17,881
Distributions reinvested – Class C		—			248			—			3,639			—			510
Redemptions – Class C		(3,109	)		(4,044	)		(21,888	)		(51,407	)		(10,176	)		(8,717	)
Net Increase/(Decrease) – Class C		(1,237	)		4,051			(15,741	)		(39,591	)		(8,216	)		9,674
Subscriptions – Class Z		127,520			175,091			278,829			387,091			2,684			23,041
Distributions reinvested – Class Z		833			1,768			—			29,748			106			1,339
Redemptions – Class Z		(59,794	)		(84,177	)		(310,353	)		(373,486	)		(6,183	)		(8,008	)
Net Increase/(Decrease) – Class Z		68,559			92,682			(31,524	)		43,353			(3,393	)		16,372
Net Increase/(Decrease) from Share Transactions		68,380			120,431			(162,617	)		(256,014	)		(32,906	)		22,812
Redemption Fees		33			171			—			—			—			—
Increase from regulatory settlements (See Note 9)		265			—			—			—			—			—
Total Increase/(Decrease) in Net Assets		163,769			(30,111	)		625,045			(1,765,359	)		1,516			(46,455	)
Net Assets:
Beginning of period		246,906			277,017			1,319,800			3,085,159			137,073			183,528
End of period	$	410,675		$	246,906		$	1,944,845		$	1,319,800		$	138,589		$	137,073
Undistributed/(Overdistributed) Net Investment Income or (Accumulated Net Investment Loss)	$	1,978		$	2,875		$	(8,359	)	$	(180	)	$	1,247		$	88

See accompanying notes to financial statements.

69

Columbia Acorn Family of Funds

Statements of Changes in Net Assets, continued

	Columbia Acorn Fund						Columbia Acorn International						Columbia Acorn USA
Changes in Shares of Beneficial Interest:	Year ended December 31,						Year ended December 31,						Year ended December 31,
(in thousands)	2009			2008			2009			2008			2009			2008
Subscriptions – Class A		33,142			26,521			6,366			8,030			3,208			2,597
Shares issued in reinvestment and capital gains – Class A		—			3,428			208			248			—			302
Less shares redeemed – Class A		(39,655	)		(49,918	)		(5,549	)		(6,693	)		(3,839	)		(3,306	)
Net Increase/(Decrease) – Class A		(6,513	)		(19,969	)		1,025			1,585			(631	)		(407	)
Subscriptions – Class B		5			80			—	*		44			—	*		3
Shares issued in reinvestment and capital gains – Class B		—			1,065			10			30			—			68
Less shares redeemed – Class B		(12,472	)		(11,645	)		(588	)		(768	)		(582	)		(573	)
Net Decrease – Class B		(12,467	)		(10,500	)		(578	)		(694	)		(582	)		(502	)
Subscriptions – Class C		3,215			3,082			497			569			148			219
Shares issued in reinvestment and capital gains – Class C		—			975			10			41			—			65
Less shares redeemed – Class C		(8,764	)		(13,528	)		(740	)		(1,414	)		(327	)		(514	)
Net Increase/(Decrease) – Class C		(5,549	)		(9,471	)		(233	)		(804	)		(179	)		(230	)
Subscriptions – Class Z		75,517			63,561			23,146			19,040			14,152			9,874
Shares issued in reinvestment and capital gains – Class Z		750			10,170			1,391			1,609			—			1,466
Less shares redeemed – Class Z		(70,272	)		(93,561	)		(18,261	)		(30,912	)		(10,509	)		(8,493	)
Net Increase/(Decrease) – Class Z		5,995			(19,830	)		6,276			(10,263	)		3,643			2,847
Net Increase/(Decrease) in Shares of Beneficial Interest		(18,534	)		(59,770	)		6,490			(10,176	)		2,251			1,708

*  Rounds to less than 500.

See accompanying notes to financial statements.

70

	Columbia Acorn International Select						Columbia Acorn Select						Columbia Thermostat Fund
Changes in Shares of Beneficial Interest:	Year ended December 31,						Year ended December 31,						Year ended December 31,
(in thousands)	2009			2008			2009			2008			2009			2008
Subscriptions – Class A		1,653			1,986			5,917			6,192			646			1,952
Shares issued in reinvestment and capital gains – Class A		22			30			—			901			1			147
Less shares redeemed – Class A		(1,497	)		(959	)		(11,758	)		(18,425	)		(1,674	)		(1,454	)
Net Increase/(Decrease) – Class A		178			1,057			(5,841	)		(11,332	)		(1,027	)		645
Subscriptions – Class B		—			10			2			16			—			176
Shares issued in reinvestment and capital gains – Class B		—			6			—			168			—			104
Less shares redeemed – Class B		(85	)		(149	)		(1,512	)		(2,059	)		(1,410	)		(1,344	)
Net Decrease – Class B		(85	)		(133	)		(1,510	)		(1,875	)		(1,410	)		(1,064	)
Subscriptions – Class C		103			317			371			469			212			1,558
Shares issued in reinvestment and capital gains – Class C		—			9			—			148			—			56
Less shares redeemed – Class C		(174	)		(183	)		(1,474	)		(2,581	)		(1,207	)		(861	)
Net Increase/(Decrease) – Class C		(71	)		143			(1,103	)		(1,964	)		(995	)		753
Subscriptions – Class Z		6,808			7,667			15,845			17,670			307			1,994
Shares issued in reinvestment and capital gains – Class Z		42			58			—			1,123			12			153
Less shares redeemed – Class Z		(3,083	)		(3,845	)		(18,178	)		(18,669	)		(727	)		(783	)
Net Increase/(Decrease) – Class Z		3,767			3,880			(2,333	)		124			(408	)		1,364
Net Increase/(Decrease) in Shares of Beneficial Interest		3,789			4,947			(10,787	)		(15,047	)		(3,840	)		1,698

See accompanying notes to financial statements.

71

Columbia Acorn Family of Funds

Financial Highlights

Columbia Acorn Fund

Class Z Shares	Year ended December 31,
Selected data for a share outstanding throughout each period	2009			2008			2007			2006			2005
Net Asset Value, Beginning of Period	$	17.71		$	29.61		$	29.71		$	28.17		$	26.45
Income from Investment Operations
Net investment income (a)		0.04			0.06			0.15	(b)		0.13			0.15
Net realized and unrealized gain/(loss)		6.98			(11.29	)		2.17			3.92			3.28
Total from Investment Operations		7.02			(11.23	)		2.32			4.05			3.43
Less Distributions to Shareholders
From net investment income		(0.05	)		(0.01	)		(0.12	)		(0.13	)		(0.15	)
From net realized gains		—			(0.66	)		(2.30	)		(2.38	)		(1.56	)
Total Distributions to Shareholders		(0.05	)		(0.67	)		(2.42	)		(2.51	)		(1.71	)
Increase from regulatory settlements		—	(c)		—			—			—			—
Net Asset Value, End of Period	$	24.68		$	17.71		$	29.61		$	29.71		$	28.17
Total Return (d)		39.65	%		(38.55	)%		7.69	%(e)(f)		14.45	%(e)		13.11	%(e)
Ratios to Average Net Assets/Supplemental Data
Net expenses (g)		0.77	%		0.76	%		0.74	%		0.74	%		0.74	%
Net investment income (g)		0.18	%		0.26	%		0.46	%		0.45	%		0.57	%
Waiver/reimbursement		—			—			0.00	%(h)		0.01	%		0.02	%
Portfolio turnover rate		27	%		21	%		20	%		22	%		16	%
Net assets at end of period (in millions)	$	10,527		$	7,446		$	13,038		$	12,128		$	10,399

(a)  Per share data was calculated using the average shares outstanding during the period.

(b)  Net investment income per share includes special dividends. The effect of these dividends amounted to $0.03 per share.

(c)  Rounds to less than $0.01 per share.

(d)  Total return at net asset value assuming all distributions reinvested.

(e)  Had the Advisor and/or Transfer Agent not waived fees and/or reimbursed a portion of expenses, total return would have been reduced.

(f)  Total return includes a voluntary reimbursement by the Advisor for a realized investment loss due to a trading error. This reimbursement increased total return and net asset value per share by less than 0.01% and less than $0.01, respectively.

(g)  The benefits derived from custody fees paid indirectly had an impact of less than 0.01%.

(h)  Rounds to less than 0.01%.

Columbia Acorn International

Class Z Shares	Year ended December 31,
Selected data for a share outstanding throughout each period	2009			2008			2007			2006			2005
Net Asset Value, Beginning of Period	$	23.13		$	43.60		$	40.31		$	33.44		$	29.03
Income from Investment Operations
Net investment income (a)		0.34			0.60			0.43			0.35			0.34
Net realized and unrealized gain/(loss)		11.31			(20.26	)		6.56			10.94			5.87
Total from Investment Operations		11.65			(19.66	)		6.99			11.29			6.21
Less Distributions to Shareholders
From net investment income		(0.53	)		(0.21	)		(0.34	)		(0.51	)		(0.72	)
From net realized gains		—			(0.60	)		(3.36	)		(3.91	)		(1.08	)
Total Distributions to Shareholders		(0.53	)		(0.81	)		(3.70	)		(4.42	)		(1.80	)
Redemption Fees
Redemption fees added to paid in capital (a)(b)		—			—			—			—			—
Increase from regulatory settlements		0.01			—			—			—			—
Net Asset Value, End of Period	$	34.26		$	23.13		$	43.60		$	40.31		$	33.44
Total Return (c)		50.97	%		(45.89	)%		17.28	%(d)		34.53	%(d)		21.81	%(d)
Ratios to Average Net Assets/Supplemental Data
Net expenses (e)		0.99	%		0.96	%		0.91	%		0.94	%		0.99	%
Net investment income (e)		1.23	%		1.72	%		0.96	%		0.92	%		1.09	%
Waiver/reimbursement		—			—			0.00	%(f)		0.01	%		0.02	%
Portfolio turnover rate		31	%		38	%		28	%		31	%		27	%
Net assets at end of period (in millions)	$	3,728		$	2,372		$	4,918		$	3,836		$	2,629

(a)  Per share data was calculated using the average shares outstanding during the period.

(b)  Rounds to less than $0.01 per share.

(c)  Total return at net asset value assuming all distributions reinvested.

(d)  Had the Advisor and/or Transfer Agent not waived fees and/or reimbursed a portion of expenses, total return would have been reduced.

(e)  The benefits derived from custody fees paid indirectly had an impact of less than 0.01%.

(f)  Rounds to less than 0.01%.

See accompanying notes to financial statements.

72

Columbia Acorn USA

Class Z Shares	Year ended December 31,
Selected data for a share outstanding throughout each period	2009			2008			2007			2006			2005
Net Asset Value, Beginning of Period	$	16.39		$	27.97		$	28.66		$	27.03		$	25.20
Income from Investment Operations
Net investment income/(loss) (a)		(0.07	)		(0.07	)		(0.01	)(b)		(0.02	)		0.07
Net realized and unrealized gain/(loss)		6.87			(10.55	)		1.03			2.26			3.18
Total from Investment Operations		6.80			(10.62	)		1.02			2.24			3.25
Less Distributions to Shareholders
From net investment income		—			—			—			—			(0.05	)
From net realized gains		—			(0.96	)		(1.71	)		(0.61	)		(1.37	)
Total Distributions to Shareholders		—			(0.96	)		(1.71	)		(0.61	)		(1.42	)
Increase from regulatory settlements		—	(c)		—			—			—			—
Net Asset Value, End of Period	$	23.19		$	16.39		$	27.97		$	28.66		$	27.03
Total Return (d)		41.49	%		(39.22	)%		3.46	%(e)(f)		8.28	%(e)		12.98	%(e)
Ratios to Average Net Assets/Supplemental Data
Net expenses (g)		1.03	%		1.01	%		0.98	%		0.98	%		1.01	%
Net investment income/(loss) (g)		(0.36	)%		(0.32	)%		(0.03	)%		(0.07	)%		0.28	%
Waiver/reimbursement		—			—			0.00	%(h)		0.01	%		0.01	%
Portfolio turnover rate		28	%		23	%		21	%		13	%		13	%
Net assets at end of period (in millions)	$	1,158		$	758		$	1,214		$	1,214		$	937

(a)  Per share data was calculated using the average shares outstanding during the period.

(b)  Net investment income per share includes special dividends. The effect of these dividends amounted to $0.09 per share.

(c)  Rounds to less than $0.01 per share.

(d)  Total return at net asset value assuming all distributions reinvested.

(e)  Had the Advisor and/or Transfer Agent not waived fees and/or reimbursed a portion of expenses, total return would have been reduced.

(f)  Total return includes a voluntary reimbursement by the Advisor for a realized investment loss due to a trading error. This reimbursement increased total return and net asset value per share by less than 0.01% and less than $0.01, respectively.

(g)  The benefits derived from custody fees paid indirectly had an impact of less than 0.01%.

(h)  Rounds to less than 0.01%.

Columbia Acorn International Select

Class Z Shares	Year ended December 31,
Selected data for a share outstanding throughout each period	2009			2008			2007			2006			2005
Net Asset Value, Beginning of Period	$	18.19		$	32.02		$	27.97		$	20.57		$	18.02
Income from Investment Operations
Net investment income (a)		0.17			0.28			0.14	(b)		0.10			0.13
Net realized and unrealized gain/(loss)		5.50			(13.53	)		5.96			7.35			2.70
Total from Investment Operations		5.67			(13.25	)		6.10			7.45			2.83
Less Distributions to Shareholders
From net investment income		(0.24	)		(0.04	)		(0.28	)		(0.05	)		(0.28	)
From net realized gains		—			(0.54	)		(1.77	)		—			—
Total Distributions to Shareholders		(0.24	)		(0.58	)		(2.05	)		(0.05	)		(0.28	)
Redemption Fees
Redemption fees added to paid in capital (a)(c)		—			—			—			—			—
Increase from regulatory settlements		0.02			—			—			—			—
Net Asset Value, End of Period	$	23.64		$	18.19		$	32.02		$	27.97		$	20.57
Total Return (d)		31.52	%		(42.10	)%		21.86	%(e)		36.27	%(e)		15.98	%(e)
Ratios to Average Net Assets/Supplemental Data
Net expenses (f)		1.20	%		1.21	%		1.18	%		1.27	%		1.45	%
Net investment income (f)		0.84	%		1.09	%		0.44	%		0.44	%		0.72	%
Waiver/reimbursement		—			—			0.00	%(g)		0.01	%		0.04	%
Portfolio turnover rate		56	%		68	%		57	%		47	%		39	%
Net assets at end of period (in millions)	$	331		$	186		$	204		$	129		$	74

(a)  Per share data was calculated using the average shares outstanding during the period.

(b)  Net investment income per share includes special dividends. The effect of these dividends amounted to $0.07 per share.

(c)  Rounds to less than $0.01 per share.

(d)  Total return at net asset value assuming all distributions reinvested.

(e)  Had the Advisor and/or Transfer Agent not waived fees and/or reimbursed a portion of expenses, total return would have been reduced.

(f)  The benefits derived from custody fees paid indirectly had an impact of less than 0.01%.

(g)  Rounds to less than 0.01%.

See accompanying notes to financial statements.

73

Columbia Acorn Family of Funds

Financial Highlights, continued

Columbia Acorn Select

Class Z Shares	Year ended December 31,
Selected data for a share outstanding throughout each period	2009			2008			2007			2006			2005
Net Asset Value, Beginning of Period	$	14.07		$	28.41		$	26.59		$	22.77		$	21.13
Income from Investment Operations
Net investment loss (a)		(0.08	)		(0.12	)		(0.07	)		(0.06	)		(0.03	)
Net realized and unrealized gain/(loss)		9.39			(13.53	)		2.53			4.51			2.35
Total from Investment Operations		9.31			(13.65	)		2.46			4.45			2.32
Less Distributions to Shareholders
From net investment income		—			—			—			(0.04	)		—
From net realized gains		—			(0.69	)		(0.64	)		(0.59	)		(0.68	)
Total Distributions to Shareholders		—			(0.69	)		(0.64	)		(0.63	)		(0.68	)
Net Asset Value, End of Period	$	23.38		$	14.07		$	28.41		$	26.59		$	22.77
Total Return (b)		66.17	%		(49.18	)%(c)		9.20	%(d)		19.68	%(d)		11.08	%(d)
Ratios to Average Net Assets/Supplemental Data
Net expenses (e)		0.99	%		0.95	%		0.91	%		0.96	%		0.99	%
Net investment loss (e)		(0.47	)%		(0.51	)%		(0.24	)%		(0.26	)%		(0.16	)%
Waiver/reimbursement		—			—			0.00	%(f)		0.02	%		0.03	%
Portfolio turnover rate		19	%		28	%		14	%		21	%		19	%
Net assets at end of period (in millions)	$	1,241		$	780		$	1,571		$	909		$	688

(a)  Per share data was calculated using the average shares outstanding during the period.

(b)  Total return at net asset value assuming all distributions reinvested.

(c)  Total return includes a voluntary reimbursement by the Advisor for a realized investment loss due to a trading error. This reimbursement increased total return and net asset value per share by 0.101% and $0.01, respectively.

(d)  Had the Advisor and/or Transfer Agent not waived fees and/or reimbursed a portion of expenses, total return would have been reduced.

(e)  The benefits derived from custody fees paid indirectly had an impact of less than 0.01%.

(f)  Rounds to less than 0.01%.

Columbia Thermostat Fund

Class Z Shares	Year ended December 31,
Selected data for a share outstanding throughout each period	2009			2008			2007			2006			2005
Net Asset Value, Beginning of Period	$	8.19		$	12.26		$	12.57		$	12.50		$	13.12
Income from Investment Operations
Net investment income (a)		0.13			0.24			0.52			0.49			0.43
Net realized and unrealized gain/(loss)		2.51			(3.96	)		0.53			0.84			0.28
Total from Investment Operations		2.64			(3.72	)		1.05			1.33			0.71
Less Distributions to Shareholders
From net investment income		(0.03	)		(0.28	)		(0.57	)		(0.54	)		(0.42	)
From net realized gains		—			(0.07	)		(0.79	)		(0.72	)		(0.91	)
Total Distributions to Shareholders		(0.03	)		(0.35	)		(1.36	)		(1.26	)		(1.33	)
Net Asset Value, End of Period	$	10.80		$	8.19		$	12.26		$	12.57		$	12.50
Total Return (b)(c)		32.29	%		(30.53	)%		8.49	%		10.86	%		5.50	%
Ratios to Average Net Assets/Supplemental Data
Net expenses (d)(e)		0.25	%		0.25	%		0.25	%		0.25	%		0.25	%
Net investment income (e)		1.48	%		2.23	%		4.05	%		3.84	%		3.28	%
Waiver/reimbursement		0.14	%		0.08	%		0.15	%		0.13	%		0.11	%
Portfolio turnover rate		17	%		130	%		128	%		66	%		96	%
Net assets at end of period (in millions)	$	42		$	35		$	36		$	31		$	26

(a)  Per share data was calculated using the average shares outstanding during the period. Recognition of net investment income by the Fund is affected by the timing of the declaration of dividends by the underlying investment companies in which the Fund invests.

(b)  Total return at net asset value assuming all distributions reinvested.

(c)  Had the Advisor and/or Transfer Agent not waived fees and/or reimbursed a portion of expenses, total return would have been reduced.

(d)  Does not include expenses of the investment companies in which the Fund invests.

(e)  The benefits derived from custody fees paid indirectly had an impact of less than 0.01%.

See accompanying notes to financial statements.

74

Columbia Acorn Family of Funds

Notes to Financial Statements

1.  Nature of Operations

Columbia Acorn Fund, Columbia Acorn International, Columbia Acorn USA, Columbia Acorn International Select, Columbia Acorn Select and Columbia Thermostat Fund (the "Funds") are each a series of Columbia Acorn Trust (the "Trust"), an open-end management investment company organized as a Massachusetts business trust. The investment objective of each Fund is to seek long-term capital appreciation.

Columbia Thermostat Fund pursues its investment objective by investing in shares of other mutual funds. As a "fund of funds," under normal circumstances the Fund allocates at least 95% of its net assets among a selected group of stock and bond mutual funds ("portfolio funds") according to the current level of the S&P 500 Index in relation to predetermined ranges set by the Advisor. The Fund may invest up to 5% of its net assets plus any cash received that day in cash, repurchase agreements, high quality short-term paper and government securities.

Each Fund may issue an unlimited number of shares. Each Fund currently has four classes of shares: Class A, Class B, Class C and Class Z. Effective February 29, 2008, the Funds no longer offer Class B shares (other than through dividend reinvestment).

Class A shares are sold with a front-end sales charge. Class A shares bought without an initial sales charge in accounts aggregating $1 million up to $50 million at the time of purchase are subject to a 1.00% contingent deferred sales charge ("CDSC") if the shares are redeemed within 12 months of the date of purchase.

Class B shares are subject to a CDSC if redeemed within six years of purchase. Class B shares will convert to Class A shares automatically eight years after purchase.

Class C shares are offered at net asset value but are subject to a CDSC on redemptions made within one year after purchase.

Class Z shares are offered at net asset value. There are certain restrictions on who may purchase Class Z shares. Generally, Class Z shares of a Fund may be exchanged for shares of another fund distributed by Columbia Management Distributors, Inc. at no additional charge.

Columbia Acorn International and Columbia Acorn International Select impose a 2.00% redemption fee on shares that are redeemed within 60 days or less of purchase. See the discussion of Fund policies regarding redemption fees in the Funds' prospectuses for more information.

The financial highlights for the Fund's Class A, Class B and Class C shares are presented in a separate annual report.

Differences in class expenses may result in payment of different dividend distributions for each class. All of the Funds' share classes have equal rights with respect to voting, subject to Fund or class specific matters.

On September 29, 2009, Bank of America Corporation, the indirect parent company of Columbia Wanger Asset Management, L.P. ("CWAM"), entered into an agreement to sell a portion of the asset management business of Columbia Management Group, LLC ("Columbia Management") to Ameriprise Financial, Inc. The transaction ("Transaction") includes a sale of CWAM. The Transaction is subject to certain approvals and other conditions to closing, and is currently expected to close in the spring of 2010.

2.  Significant Accounting Policies

The preparation of financial statements in accordance with accounting principles generally accepted in the United States of America ("GAAP") requires management to make certain estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosures of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. Actual results could differ from those estimates.

Management has evaluated the events and transactions that have occurred through February 18, 2010, the date the financial statements were issued, and noted no items requiring adjustment of the financial statements or additional disclosures. The following is a summary of significant accounting policies consistently followed by the Funds in the preparation of their financial statements.

>Security valuation

Securities of the Funds are valued at market value or, if a market quotation for a security is not readily available or is deemed not to be reliable because of events or circumstances that have occurred between the market quotation and the time as of which the security is to be valued, the security is valued at a fair value determined in good faith under consistently applied procedures established by the Board of Trustees. With respect to Columbia Thermostat Fund, investments in portfolio funds are valued at their net asset values as reported by the portfolio funds. A security traded on a securities exchange or in an over-the-counter market in which transaction prices are reported is valued at the last sales price at the time of valuation. A security traded principally on NASDAQ is valued at the NASDAQ official closing price. Mutual Funds and Exchange Traded Funds are valued at their closing net asset value as reported to NASDAQ . A security for which there is no reported sale on the valuation date is valued

75

Columbia Acorn Family of Funds

Notes to Financial Statements, continued

at the latest bid quotation. Short-term investments maturing in 60 days or less are valued at amortized cost, which approximates market value. A security for which a market quotation is not readily available and any other assets are valued at its fair value determined in good faith under consistently applied procedures established by the Board of Trustees. The Funds have retained an independent statistical fair value pricing service that employs a systematic methodology to assist in the fair valuation process for securities principally traded in a foreign market in order to adjust for possible changes in value that may occur between the close of the foreign exchange and the time as of which the securities are to be valued. If a security is valued at fair value, that value may be different from the last quoted market price for the security.

Various inputs are used in determining the value of each Fund's investments. These inputs are summarized in the three broad levels listed below:

• Level 1 – quoted prices in active markets for identical securities

• Level 2 – other significant observable inputs (including quoted prices for similar securities, interest rates, prepayment speeds, credit risk and others)

• Level 3 – significant unobservable inputs (including management's own assumptions in determining the value of investments)

The inputs or methodologies used for valuing securities are not necessarily an indication of the risk associated with investing in those securities.

Examples of the types of securities in which the Funds would typically invest and how they are classified within this hierarchy are as follows. Typical Level 1 securities include exchange traded domestic equities, mutual funds whose NAVs are published each day and exchange traded foreign equities that are not statistically fair valued. Typical Level 2 securities include exchange traded foreign equities that are statistically fair valued, forward foreign currency exchange contracts and short-term investments valued at amortized cost. Additionally, securities fair valued by the Fund's Valuation Committee that rely on significant observable inputs are also included in level 2. Typical Level 3 securities include any security fair valued by the Funds' Valuation Committee that relies on significant unobservable inputs.

>Repurchase agreements

Each Fund may engage in repurchase agreement transactions. Each Fund, through its custodian, receives delivery of underlying securities collateralizing repurchase agreements. The counterparty is required to maintain collateral that is at all times at least equal to the repurchase price including interest. In the event of default or bankruptcy by the counterparty to the agreement, realization and/or retention of the collateral may be subject to legal proceedings.

>Foreign currency translations

Values of investments denominated in foreign currencies are converted into U.S. dollars using the New York spot market rate of exchange at the time of valuation. Purchases and sales of investments and dividend and interest income are translated into U.S. dollars using the spot market rate of exchange prevailing on the respective dates of such transactions. The gain or loss resulting from changes in foreign exchange rates is included with net realized and unrealized gain or loss from investments, as appropriate.

>Forward foreign currency exchange contracts

Columbia Acorn International may enter into forward foreign currency exchange contracts in order to seek to minimize the risk from adverse changes in the relationship between the U.S. dollar and foreign currencies. A forward foreign currency exchange contract is a commitment to purchase or sell a foreign currency at a future date at a negotiated forward rate. Forward foreign currency exchange contracts are valued at the interpolated forward exchange rate of the underlying currencies and any market gain or loss, arising from the difference between the original value and the current value of such contract, is included as a component of unrealized gain/(loss) on the Statements of Operations. Open forward foreign currency exchange contracts, if any, are disclosed in the Notes to the Statement of Investments. As forward foreign currency exchange contracts are closed the resulting gain or loss, arising from the difference between the original value of the contract and the closing value of such contract, is included as a component of realized gain/(loss) on the Statements of Operations.

A forward foreign currency exchange contract would limit the risk of loss due to a decline in the value of a particular currency; however, it also would limit any potential gain that might result should the value of the currency increase instead of decrease. These contracts may involve market risk in excess of the unrealized gain or loss reflected on the Statements of Assets and Liabilities. In addition, a Fund could be exposed to counterparty risks if counterparties to the contracts are unable to meet the terms of their contracts. The counterparty risk exposure is, therefore, closely monitored and contracts are only executed with high credit quality financial institutions.

76

A Fund may use forward foreign currency exchange contracts to buy or sell a foreign currency when the Advisor believes it has exposure to a foreign currency which may suffer or enjoy a movement against another foreign currency to which the Fund has exposure. A Fund will not attempt to hedge all of its foreign portfolio positions.

For additional information on derivative instruments, please see Note 5.

>Securities lending

Each Fund may lend securities up to one-third of the value of its total assets to certain approved brokers, dealers and other financial institutions to earn additional income. In lending its securities, the Fund retains the benefits of owning the securities, including receipt of dividends or interest generated by the security. Each Fund also receives a fee for the loan. Each Fund has the ability to recall the loans at any time and could do so in order to vote proxies or to sell the loaned securities. Each loan is collateralized by cash that exceeds the value of the securities on loan. The market value of the loaned securities is determined daily at the close of business of each Fund and any additional required collateral is delivered to each Fund on the next business day. Each Fund has elected to invest the cash collateral in the Dreyfus Government Cash Management Fund, and the income earned is paid to each Fund, net of any fees remitted to Goldman Sachs Agency Lending as the lending agent and net of any borrower rebates. The Funds' advisor, CWAM, does not retain any fees earned by the lending program. Generally, in the event of borrower default, a Fund has the right to use the collateral to offset any losses incurred. In the event a Fund is delayed or prevented from exercising its right to dispose of the collateral, there may be a potential loss to a Fund. Some of these losses may be indemnified by the lending agent. Each Fund bears the risk of loss with respect to the investment of collateral.

The net lending income earned in 2009 by each Fund is included in the Statements of Operations.

>Security transactions and investment income

Security transactions, investment income and shareholder fund transactions are accounted for on the trade date (date the order to buy or sell is executed) and dividend income and realized gain distributions from other funds are recorded on the ex-dividend date, except that certain dividends from foreign securities are recorded as soon as the information is available to the Funds. Interest income is recorded on the accrual basis and includes amortization of discounts on debt obligations when required for federal income tax purposes. Realized gains and losses from security transactions are recorded on an identified cost basis.

Awards, if any, from class action litigation related to securities owned may be recorded as a reduction of cost of those securities. If the applicable securities are no longer owned, the proceeds are recorded as realized gains.

The Funds estimate the tax character of distributions from real estate investment trusts ("REITs"). Distributions received in excess of income are recorded as a reduction of the cost of the related investments. If the applicable securities are no longer owned, any distributions received in excess of income are recorded as realized gains.

>Restricted Securities

Restricted securities are securities that may only be resold upon registration under federal securities laws or in transactions exempt from registration. In some cases, the issuer of restricted securities has agreed to register such securities for resale at the issuer's expense either upon demand by the Funds or in connection with another registered offering of the securities. Many restricted securities may be resold in the secondary market in transactions exempt from registration. Such restricted securities may be determined to be liquid under criteria established by the Board of Trustees.

>Fund share valuation

Fund shares are sold and redeemed on a continuing basis at net asset value, subject to any applicable sales charge. Net asset value per share is determined daily as of the close of trading on the New York Stock Exchange ("NYSE") on each day the NYSE is open for trading. Generally, income, expenses and realized and unrealized gain/(losses) of a Fund are allocated to each class proportionately on a daily basis for purposes of determining the net asset value of each class. The Rule 12b-1 service and distribution fees, if any, and transfer agency fees are charged to each specific class as expenses are incurred. Redemption fees are accounted for as an addition to paid in capital for purposes of determining the net asset value of each class.

>Custody fees/credits

Custody fees are reduced based on each Fund's cash balances maintained with the custodian. The amount is disclosed as a reduction of total expenses on the Statements of Operations.

>Federal income taxes

The Funds have complied with the provisions of the Internal Revenue Code available to regulated investment companies and, in the manner provided therein, distribute all their taxable income, as well as any net realized gain on sales of investments and foreign currency transactions reportable for federal income tax purposes. Columbia Thermostat Fund distributes all of its

77

Columbia Acorn Family of Funds

Notes to Financial Statements, continued

taxable income, as well as any net realized gain on sales of portfolio fund shares and any distributions of net realized gains received by the Fund from its portfolio funds, reportable for federal income tax purposes. Accordingly, the Funds paid no federal income taxes and no federal income tax provision was required.

>Foreign capital gains taxes

Realized gains in certain countries may be subject to foreign taxes at the fund level, at rates ranging from approximately 10% to 15%. The Funds accrue for such foreign taxes on net realized and unrealized gains at the appropriate rate for each jurisdiction.

>Distributions to Shareholders

Distributions to shareholders are recorded on the ex-dividend date.

>Indemnification

In the normal course of business, the Trust on behalf of the Funds enters into contracts that contain a variety of representations and warranties and that provide general indemnities. A Fund's maximum exposure under these arrangements is unknown, as this would involve future claims against the Fund. Also, under the Trust's organizational documents, the trustees and officers of the Trust are indemnified against certain liabilities that may arise out of their duties to the Trust. However, based on experience, the Funds expect the risk of loss due to these warranties and indemnities to be minimal.

3.  Federal Tax Information

The timing and character of income and capital gain distributions are determined in accordance with income tax regulations, which may differ from GAAP. Reclassifications are made to each Fund's capital accounts for permanent tax differences to reflect income and gains available for distribution (or available capital loss carryforwards) under income tax regulations.

For the year ended December 31, 2009, permanent book and tax basis differences resulting primarily from differing treatments for proceeds from litigation settlements, net operating losses, foreign currency transactions, passive foreign investment company ("PFIC") adjustments and foreign capital gains tax adjustments were identified and reclassified among the components of each Fund's net assets as follows:

	Undistributed/ (Overdistributed) or (Accumulated) Net Investment Income (Loss)			Accumulated Net Realized Gain/(Loss)			Paid-in Capital
(in thousands)
Columbia Acorn Fund	$	(189	)	$	229		$	(40	)
Columbia Acorn International		2,600			(2,551	)		(49	)
Columbia Acorn USA		4,809			—			(4,809	)
Columbia Acorn International Select		238			28			(266	)
Columbia Acorn Select		2,193			(589	)		(1,604	)
Columbia Thermostat Fund		—	*		—	*		—

*Represents less than $500.

Net investment income and net realized gains/(losses), as disclosed on the Statements of Operations, and net assets were not affected by these reclassifications.

The tax character of distributions paid during the years ended December 31, 2009 and December 31, 2008 was as follows:

December 31, 2009	Ordinary Income*		Long-Term Capital Gains
(in thousands)
Columbia Acorn Fund	$	20,981	$	—
Columbia Acorn International		60,207		—
Columbia Acorn USA		—		—
Columbia Acorn International Select		3,533		—
Columbia Acorn Select		—		—
Columbia Thermostat Fund		122		—
December 31, 2008	Ordinary Income*		Long-Term Capital Gains
(in thousands)
Columbia Acorn Fund	$	24,585	$	412,506
Columbia Acorn International		32,574		74,297
Columbia Acorn USA		9		53,514
Columbia Acorn International Select		601		4,740
Columbia Acorn Select		—		74,125
Columbia Thermostat Fund		3,595		824

*For tax purposes short-term capital gain distributions, if any, are considered ordinary income distributions.

As of December 31, 2009, the components of distributable earnings on a tax basis were as follows:

	Undistributed Ordinary Income		Undistributed Long-Term Capital Gains		Net Unrealized Appreciation (Depreciation)*
(in thousands)
Columbia Acorn Fund	$	13,908	$	—	$	3,885,370
Columbia Acorn International		78,049		—		1,017,469
Columbia Acorn USA		—		—		284,766
Columbia Acorn International Select		6,032		—		77,602
Columbia Acorn Select		—		—		222,742
Columbia Thermostat Fund		1,276		—		(1,424	)

*The differences between book-basis and tax-basis net unrealized appreciation/(depreciation) are primarily due to deferral of losses from wash sales and PFIC adjustments.

The following capital loss carryforwards, determined as of December 31, 2009, may be available to reduce taxable income

78

arising from future net realized gains on investments, if any, to the extent permitted by the Internal Revenue Code:

	Year of Expiration
	2010			2011- 2015		2016		2017		Total
(in thousands)
Columbia Acorn Fund	$	—		$	—	$	—	$	409,911	$	409,911
Columbia Acorn International		—			—		135,487		489,443		624,930
Columbia Acorn USA		1,518	*		—		76,008		36,216		113,742
Columbia Acorn International Select		—			—		30,442		46,457		76,899
Columbia Acorn Select		—			—		12,271		115,445		127,716
Columbia Thermostat Fund		—			—		5,193		21,738		26,931

*Remains from Columbia Acorn USA's merger with Stein Roe Small Company Growth Fund on 7/26/2002. Utilization of Stein Roe Small Company Growth Fund's losses could be subject to limitations imposed by the Internal Revenue Code.

Under current tax rules, certain currency and capital losses realized after October 31 may be deferred and treated as occurring on the first day of the following fiscal year. As of December 31, 2009, post-October currency and capital losses attributed to security transactions were deferred to January 1, 2010 as follows:

	Currency		Capital
(in thousands)
Columbia Acorn Fund	$	—	$	6,311
Columbia Acorn International		—		—
Columbia Acorn USA		—		10,041
Columbia Acorn International Select		—		1,985
Columbia Acorn Select		95		—
Columbia Thermostat Fund		—		624

Management is required to determine whether a tax position of the Funds is more likely than not to be sustained upon examination by the applicable taxing authority, including resolution of any related appeals or litigation processes, based on the technical merits of the position. The tax benefit to be recognized by the Funds is measured as the largest amount of benefit that is greater than fifty percent likely of being realized upon ultimate settlement. Management is not aware of any tax positions for which it is reasonably possible that the total amounts of unrecognized tax benefits will significantly change in the next twelve months. However, management's conclusions may be subject to review and adjustment at a later date based on factors including, but not limited to, new tax laws, regulations, and administrative interpretations (including relevant court decisions). The Funds' federal tax returns for the prior three fiscal ye ars remain subject to examination by the Internal Revenue Service.

4.  Transactions with Affiliates

CWAM is a wholly owned subsidiary of Columbia Management, which in turn is an indirect, wholly owned subsidiary of Bank of America Corporation ("BOA"). CWAM furnishes continuing investment supervision to the Funds and is responsible for the overall management of the Funds' business affairs.

Under each Fund's investment advisory agreement, management fees were accrued daily based on each Fund's average daily net assets and paid monthly to CWAM at the annual rates shown in the table below for each Fund.

Columbia Acorn Fund

Average Daily Net Assets	Annual Fee Rate
Up to $700 million		0.74	%
$700 million to $2 billion		0.69	%
$2 billion to $6 billion		0.64	%
$6 billion and over		0.63	%

Columbia Acorn International

Average Daily Net Assets	Annual Fee Rate
Up to $100 million		1.19	%
$100 million to $500 million		0.94	%
$500 million and over		0.74	%

Columbia Acorn USA

Average Daily Net Assets	Annual Fee Rate
Up to $200 million		0.94	%
$200 million to $500 million		0.89	%
$500 million to $2 billion		0.84	%
$2 billion to $3 billion		0.80	%
$3 billion and over		0.70	%

Columbia Acorn International Select

Average Daily Net Assets	Annual Fee Rate
Up to $500 million		0.94	%
$500 million and over		0.90	%

Columbia Acorn Select

Average Daily Net Assets	Annual Fee Rate
Up to $700 million		0.85	%
$700 million to $2 billion		0.80	%
$2 billion to $3 billion		0.75	%
$3 billion and over		0.70	%

Columbia Thermostat Fund

	Annual Fee Rate
All Average Daily Net Assets		0.10	%

79

Columbia Acorn Family of Funds

Notes to Financial Statements, continued

For the year ended December 31, 2009, the Funds' effective investment advisory fee rates were as follows:

Columbia Acorn Fund	0.65	%
Columbia Acorn International	0.78	%
Columbia Acorn USA	0.87	%
Columbia Acorn International Select	0.94	%
Columbia Acorn Select	0.82	%
Columbia Thermostat Fund	0.10	%

>Expense Limit

CWAM has voluntarily agreed to reimburse the ordinary operating expenses (exclusive of brokerage commissions, interest, taxes and extraordinary expenses, but inclusive of custodian charges relating to overdrafts, if any) after giving effect to any balance credits from the Funds' custodian, exceeding 1.45% annually of the average daily net assets for Columbia Acorn International Select and 1.35% annually of the average daily net assets for Columbia Acorn Select. This arrangement may be modified or terminated by either the Funds or CWAM on 30 days notice.

CWAM has contractually agreed to waive fees and/or reimburse expenses of Columbia Thermostat Fund so that the ordinary operating expenses (exclusive of interest and fees on borrowings, and expenses associated with the Fund's investment in other investment companies, but including custodian charges relating to overdrafts, if any), after giving effect to any balance credits from the Fund's custodian, will not exceed 0.25% annually of the Fund's average daily net assets through April 30, 2010. There is no guarantee that this arrangement will continue thereafter.

Expenses reimbursed by CWAM to Columbia Acorn International Select and Columbia Thermostat Fund for year ended December 31, 2009, were $4,729 and $326,907, respectively.

CWAM provides administrative services and receives an administration fee from the Funds at the following annual rates:

Columbia Acorn Trust

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

For the year ended December 31, 2009, each Fund's effective administration fee rate was 0.04% of average daily net assets. CWAM has delegated to Columbia Management Advisors, LLC, an indirect, wholly owned subsidiary of BOA, responsibility to provide certain sub-administrative services to the Funds.

Columbia Management Distributors, Inc. ("CMDI"), a wholly owned subsidiary of BOA, is the Funds' principal underwriter.

Each Fund has adopted a Rule 12b-1 (distribution and service) plan which requires it to pay CMDI a monthly service fee equal to 0.25% annually of the average daily net assets attributable to Class A, Class B and Class C shares and a monthly distribution fee equal to 0.50% and 0.75%, annually, of the average daily net assets attributable to Class B and Class C shares, respectively. CMDI receives no compensation with respect to Class Z shares.

Columbia Management Services, Inc. (the "Transfer Agent"), an indirect, wholly owned subsidiary of BOA, provides shareholder services to the Funds. For such services, each Fund pays the Transfer Agent a monthly fee at the annual rate of $17.00 per account. The Transfer Agent also receives reimbursement for certain out-of-pocket expenses and sub-transfer agency expenses.

Certain officers and trustees of the Trust are also officers of CWAM. The Trust makes no direct payments to its officers and trustees who are affiliated with CWAM.

The Board of Trustees appointed a Chief Compliance Officer to the Trust in accordance with federal securities regulations. The Funds, along with other affiliated funds, pay their pro-rata share of the expenses associated with the Office of the Chief Compliance Officer. Those expenses are disclosed separately as "Chief compliance officer expenses" in the Statements of Operations.

The Trust offers a deferred compensation plan for its independent trustees. Under that plan, a trustee may elect to defer all or a portion of his or her compensation. Amounts deferred are retained by the Trust and may represent an unfunded obligation of the Trust. The value of amounts deferred is determined by reference to the change in value of Class Z shares of one or more series of the Trust or a money market fund specified by the trustee. Benefits under the deferred compensation plan are payable when the trustee ceases to be a member of the Board of Trustees.

An affiliated person of a Fund may include any company in which a Fund owns five percent or more of its outstanding voting shares. On December 31, 2009, Columbia Acorn Fund, Columbia Acorn International, Columbia Acorn USA and Columbia Acorn Select each held five percent or more of the outstanding voting securities of one or more companies.

80

Details of investments in those affiliated companies are presented on pages 29, 30, 39, 50 and 61, respectively.

During the year ended December 31, 2009, the Funds engaged in purchase and sale transactions with funds that have a common investment advisor (or affiliated investment advisors), common directors/trustees, and/or common officers. Those transactions complied with Rule 17a-7 under the Investment Company Act of 1940 and were as follows:

	Purchases		Sales
(in thousands)
Columbia Acorn International	$	7,422	$	—
Columbia Acorn Select		—		1,655

5.  Objectives and Strategies for Investing in Derivative Instruments

Columbia Acorn International uses derivatives instruments including forward foreign currency exchange contracts in order to meet its investment objectives. The Fund employs strategies in differing combinations to permit it to increase, decrease or change the level of exposure to market risk factors. The achievement of any strategy involving derivatives depends on analysis of various risk factors, and if the strategies for the use of derivatives do not work as intended, the Fund may not achieve its investment objectives.

In pursuit of its investment objectives, the Fund is exposed to the following market risk:

Foreign Exchange Rate Risk: Foreign exchange rate risk relates to the change in the U.S. dollar value of a security held that is denominated in a foreign currency. The U.S. dollar value of a foreign-currency-denominated security will decrease as the dollar appreciates against the currency, while the U.S. dollar value will increase as the dollar depreciates against the currency.

The following notes provide more detailed information about the derivative type held by the Columbia Acorn International:

Forward Foreign Currency Exchange Contracts

• The Fund entered into forward foreign currency exchange contracts to shift its investment exposure from one currency to another.

• The Fund used forward foreign currency exchange contracts to shift its U.S. dollar exposure in order to achieve a representative weighted mix of major currencies relative to its benchmark and/or to recover an underweight country exposure in its portfolio relative to its benchmark.

Forward foreign currency exchange contracts are agreements to exchange one currency for another at a future date at a specified price. These contracts are used to minimize the exposure to foreign exchange rate fluctuations during the period between the trade and settlement dates of the contract. The Fund may utilize forward foreign currency exchange contracts in connection with the settlement of purchases and sales of securities. The Fund may also enter into these contracts to reduce the exposure to adverse price movements in certain other foreign-currency-denominated assets. Contracts to buy are used to acquire exposure to foreign currencies, while contracts to sell are used to reduce the exposure to foreign exchange rate fluctuations. Forward foreign currency exchange contracts are valued daily at the current exchange rate of the underlying currency, resulting in unrealized gains (losses) which become realized at the time the forward foreign currency exchange contracts are closed or mature. Realized and unrealized gains (losses) arising from such transactions are included in net realized and unrealized gains (losses) on foreign currency transactions. The use of forward foreign currency exchange contracts does not eliminate fluctuations in the prices of the Fund's portfolio securities. While the maximum potential loss from such contracts is the aggregate face value in U.S. dollars at the time the contract was opened, exposure is typically limited to the change in value of the contract (in U.S. dollars) over the period it remains open. The Fund could also be exposed to risk that counterparties of the contracts may be unable to fulfill the terms of the contracts.

During the year ended December 31, 2009, Columbia Acorn International entered into 122 forward foreign currency exchange contracts.

The following table is a summary of the value of the Columbia Acorn International's derivative instruments as of December 31, 2009.

  Fair Value of Derivative Instruments

	Asset
	Statement of Assets and Liabilities	Fair Value
(in thousands)
	Unrealized appreciation on forward foreign currency exchange contracts	$6,689
	Liability
	Statement of Assets and Liabilities	Fair Value
(in thousands)
	Unrealized depreciation on forward foreign currency exchange contracts	$(4,205)

81

Columbia Acorn Family of Funds

Notes to Financial Statements, continued

The effect of derivative instruments on the Columbia Acorn International's Statement of Operations for the year ended December 31, 2009 was as follows:

Amount of Realized Gain or (Loss) and Change in Unrealized Appreciation or (Depreciation)
on Derivatives Recognized in Income

	Risk Exposure	Realized Gain/(Loss)		Change in Unrealized Appreciation/ (Depreciation)
(in thousands)
Forward foreign currency exchange contracts	Foreign Exchange Rate Risk	$	4,507	$	5,763

6.  Borrowing Arrangements

The Trust participated in a $150 million credit facility, along with another Trust managed by CWAM, which was entered into to facilitate portfolio liquidity. Under the facility, interest is charged to each participating fund based on its borrowings at a rate per annum equal to the higher of Federal Funds Rate or Overnight LIBOR plus 0.75%. In addition, a commitment fee of 0.12% per annum of the unutilized line of credit was accrued and apportioned among the participating funds based on their relative net assets. The commitment fee is included in "Other expenses" in the Statements of Operations. No amounts were borrowed by any Fund under this facility for the year ended December 31, 2009. The Trust enters into this line of credit for one year durations. The Trust has secured the line of credit for the entire year of 2010.

7.  Investment Transactions

The aggregate cost of purchases and proceeds from sales, other than short-term obligations, for the year ended December 31, 2009, were:

Columbia Acorn Fund

(in thousands)
Investment securities
Purchases	$	3,110,424
Proceeds from sales		3,561,995

Columbia Acorn International

(in thousands)
Investment securities
Purchases	$	1,154,358
Proceeds from sales		1,014,864

Columbia Acorn USA

(in thousands)
Investment securities
Purchases	$	355,188
Proceeds from sales		305,733

Columbia Acorn International Select

(in thousands)
Investment securities
Purchases	$	233,777
Proceeds from sales		170,251

Columbia Acorn Select

(in thousands)
Investment securities
Purchases	$	280,494
Proceeds from sales		568,076

Columbia Thermostat Fund

(in thousands)
Investment securities
Purchases	$	22,134
Proceeds from sales		56,558

8.  Redemption Fees

For the year ended December 31, 2009, the redemption fees imposed by Columbia Acorn International and Columbia Acorn International Select amounted to approximately $259,441 and $33,449, respectively, and are accounted for as additions to paid in capital.

9.  Regulatory Settlements with Third Parties

During the year ended December 31, 2009, Columbia Acorn Fund, Columbia Acorn International, Columbia Acorn USA and Columbia Acorn International Select received payments totaling $39,819, $1,210,287, $4,593 and $265,461, respectively, representing distributions from a fair fund established in connection with a regulatory settlement between the Securities and Exchange Commission and a third party broker dealer relating to alleged market timing and late trading in mutual funds, including the Funds. The payments have been included in "Increase from regulatory settlements" on the Statements of Changes in Net Assets.

10.  Legal Proceedings

The Trust, CWAM and the Trustees of the Trust (collectively, the "Columbia defendants") are named as defendants in class and derivative complaints that have been consolidated in a Multi-District Action (the "MDL Action") in the federal district court of Maryland. These lawsuits contend that defendants permitted certain investors to market time their trades in certain Columbia Acorn Funds. The MDL Action is ongoing. However, all claims against the Trust and the independent trustees of the Trust have been dismissed.

The Trust and CWAM are also defendants in a class action lawsuit that alleges, in summary, that the Trust and CWAM exposed shareholders of Columbia Acorn International Fund to trading by market timers by allegedly: (a) failing to properly

82

evaluate daily whether a significant event affecting the value of the Fund's securities had occurred after foreign markets had closed but before the calculation of the Fund's net asset value ("NAV"); (b) failing to implement the Fund's portfolio valuation and share pricing policies and procedures; and (c) failing to know and implement applicable rules and regulations concerning the calculation of NAV (the "Fair Valuation Lawsuit"). The Seventh Circuit ruled that the plaintiffs' state law claims were preempted under federal law resulting in the dismissal of plaintiffs' complaint. Plaintiffs appealed the Seventh Circuit's ruling to the United States Supreme Court. The Supreme Court reversed the Seventh Circuit's ruling on jurisdictional grounds and the case was ultimately remanded to the state court.

On March 21, 2005, a class action complaint was filed against the Trust and CWAM seeking to rescind the CDSC assessed upon redemption of Class B shares of Columbia Acorn Funds due to the alleged market timing of the Columbia Acorn Funds (the "CDSC Lawsuit"). In addition to the rescission of sales charges, plaintiffs seek recovery of actual damages, attorneys' fees and costs. The case had been transferred to the MDL Action in the federal district court of Maryland.

On September 14, 2007, the plaintiffs and the Columbia defendants named in the MDL Action, including the Columbia Funds, entered into a stipulation of settlement with respect to all Columbia-related claims in the MDL Action described above, including the CDSC and Fair Valuation Lawsuits. The settlement is subject to court approval.

Columbia Acorn Trust and CWAM intend to defend these suits vigorously. CWAM believes that the lawsuits are not likely to materially affect its ability to provide investment management services to the Funds.

83

Report of Independent Registered Public Accounting Firm

To the Board of Trustees and Shareholders of
Columbia Acorn Trust:

In our opinion, the accompanying statement of assets and liabilities, including the schedule of investments, and the related statements of operations and of changes in net assets and the financial highlights present fairly, in all material respects, the financial position of Columbia Acorn Fund, Columbia Acorn International, Columbia Acorn USA, Columbia Acorn International Select, Columbia Acorn Select and Columbia Thermostat Fund (each a series of the Columbia Acorn Trust, hereinafter referred to as the "Funds") at December 31, 2009, the results of its operations for the year then ended, the changes in its net assets for each of the two years in the period then ended and the financial highlights for each of the five years in the period then ended, in conformity with accounting principles generally accepted in the United States of America. These financial statements and financial highlights (hereafter referred to as "financial s tatements") are the responsibility of the Funds' management; our responsibility is to express an opinion on these financial statements based on our audits. We conducted our audits of these financial statements in accordance with the standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement. An audit includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements, assessing the accounting principles used and significant estimates made by management, and evaluating the overall financial statement presentation. We believe that our audits, which included confirmation of securities at December 31, 2009 by correspondence with the custodian and brokers, provide a reasonable basis for our opinion.

PricewaterhouseCoopers LLP
Chicago, Illinois
February 18, 2010

84

Columbia Acorn Family of Funds

Federal Income Tax Information (in thousands) (unaudited) — Class A, B, C and Z shares

Columbia Acorn Fund

100.00% of the ordinary income distributed by the Fund, for the fiscal year ended December 31, 2009 qualified for the corporate dividends received deduction.

For non-corporate shareholders 100.00%, or the maximum amount allowable under the Jobs and Growth Tax Relief Reconciliation Act of 2003, of ordinary income distributed by the Fund for the fiscal year ended December 31, 2009 may represent qualified dividend income.

Columbia Acorn International

Foreign taxes paid during the fiscal year ended December 31, 2009, of $6,483 are being passed through to shareholders. This represents $0.05 per share. Eligible shareholders may claim this amount as a foreign tax credit.

Gross income derived from sources within foreign countries was $81,906 ($0.63 per share) for the fiscal year ended December 31, 2009.

For non-corporate shareholders 82.95%, or the maximum amount allowable under the Jobs and Growth Tax Relief Reconciliation Act of 2003, of ordinary income distributed by the Fund for the fiscal year ended December 31, 2009 may represent qualified dividend income.

Columbia Acorn International Select

Foreign taxes paid during the fiscal year ended December 31, 2009, of $521 are being passed through to shareholders. This represents $0.03 per share. Eligible shareholders may claim this amount as a foreign tax credit.

Gross income derived from sources within foreign countries was $6,377 ($0.37 per share) for the fiscal year ended December 31, 2009.

13.08% of the ordinary income distributed by the Fund, for the fiscal year ended December 31, 2009 qualified for the corporate dividends received deduction.

For non-corporate shareholders 100.00%, or the maximum amount allowable under the Jobs and Growth Tax Relief Reconciliation Act of 2003, of ordinary income distributed by the Fund for the fiscal year ended December 31, 2009 may represent qualified dividend income.

Columbia Thermostat Fund

100.00% of the ordinary income distributed by the Fund for the fiscal year ended December 31, 2009, qualifies for the corporate dividends received deduction.

For non-corporate shareholders, 100.00% or the maximum amount allowable under the Jobs and Growth Tax Relief Reconciliation Act of 2003, of the ordinary income distributed by the Fund for the fiscal year ended December 31, 2009 may represent qualified dividend income.

85

Board of Trustees and Management of
Columbia Acorn Funds

Each trustee may serve a term of unlimited duration. The Trust's By-laws generally require that a trustee retire at the end of the calendar year in which the trustee attains the age of 75 years. The trustees appoint their own successors, provided that at least two-thirds of the trustees, after such appointment, have been elected by shareholders. Shareholders may remove a trustee, with or without cause, upon the vote of two-thirds of the Trust's outstanding shares at any meeting called for that purpose. A trustee may be removed, with or without cause, upon the vote of a majority of the trustees. The names of the trustees and officers of the Trust, the date each was first elected or appointed to office, their principal business occupations during at least the last five years, number of portfolios in the fund complex they oversee, and other directorships they hold, are shown below. Each trustee serves in such capacity for each of t he six series of Columbia Acorn Trust and for each of the four series of Wanger Advisors Trust.

The address for the trustees and officers of the Trust is Columbia Wanger Asset Management, L.P., 227 West Monroe Street, Suite 3000, Chicago, Illinois 60606. The Funds' Statement of Additional Information includes additional information about the Funds' trustees and officers. You may obtain a free copy of the Statement of Additional Information by writing or calling toll-free:

Columbia Wanger Asset Management, L.P.
Shareholder Services Group
227 W. Monroe, Suite 3000
Chicago IL 60606
1-800-922-6769

Name, Position(s) with Columbia Acorn Trust and Age at December 31, 2009	Year First Elected or Appointed to Office*		Principal Occupation(s) during Past Five Years	Number of Portfolios in Fund Complex Overseen by Trustee/Officer		Other Directorships in addition to Columbia Acorn Trust
Trustees who are not interested persons of Columbia Acorn Trust:
Laura M. Born, 44, Trustee		2007	Adjunct Assistant Professor of Finance, University of Chicago Booth School of Business; formerly, Managing Director – Investment Banking, J.P. Morgan Chase & Co. (broker/dealer) 2002-2007.		10	Wanger Advisors Trust
Michelle L. Collins, 49, Trustee		2008	President, Cambium LLC (financial advisory firm) since 2007; Advisory Board Member, Svoboda Capital Partners LLC (private equity firm) since 2007; Managing Director Svoboda Capital Partners LLC, 1998-2006.		10	Wanger Advisors Trust; Bucyrus International, Inc. (mining equipment manufacturer); Molex, Inc. (electronics components manufacturer).
Maureen M. Culhane, 61, Trustee		2007	Retired. Formerly, Vice President, Goldman Sachs Asset Management, L.P. (investment advisor), 2005-2007, and Vice President (Consultant) – Strategic Relationship Management, Goldman Sachs AG, 1999-2005.		10	Wanger Advisors Trust
Margaret M. Eisen, 56, Trustee		2002	Chief Investment Officer, EAM International LLC (corporate finance and asset management) since 2003; Managing Director, CFA Institute, 2005-2008.		10	Wanger Advisors Trust; Antigenics, Inc. (biotechnology and pharmaceuticals) (until June 2009).
Jerome Kahn, Jr., 75,(1) Trustee		1987	Portfolio manager and stock analyst; formerly, President, William Harris Investors, Inc. (investment advisor).		10	Wanger Advisors Trust
Steven N. Kaplan, 50, Trustee and Vice Chairman of the Board		1999	Neubauer Family Professor of Entrepreneurship and Finance, University of Chicago Booth School of Business.		10	Wanger Advisors Trust; Accretive Health, Inc. (healthcare management services provider); Morningstar, Inc. (provider of independent investment research).
David C. Kleinman, 74, Trustee		1972	Adjunct Professor of Strategic Management, University of Chicago Booth School of Business; business consultant.		10	Wanger Advisors Trust; Sonic Foundry, Inc. (rich media systems and software).
Allan B. Muchin, 73, Trustee		1998	Chairman Emeritus, Katten Muchin Rosenman LLP (law firm).		10	Wanger Advisors Trust

86

Name, Position(s) with Columbia Acorn Trust and Age at December 31, 2009	Year First Elected or Appointed to Office*		Principal Occupation(s) during Past Five Years	Number of Portfolios in Fund Complex Overseen by Trustee/Officer		Other Directorships in addition to Columbia Acorn Trust
Trustees who are not interested persons of Columbia Acorn Trust: (continued)
James A. Star, 48, Trustee and Chairman of the Board		2006	President, Longview Asset Management LLC (investment advisor) since 2003; Director, Traush Industries (privately-owned manufacturer of refrigeration parts and products).		10	Wanger Advisors Trust
John A. Wing, 74, Trustee		2002	Partner, Dancing Lion Partners (investment firm); prior thereto, Frank Wakely Gunsaulus Professor of Law and Finance and Chairman of the Center for the Study of Law and Financial Markets, Illinois Institute of Technology; formerly, Chairman of the Board and Chief Executive Officer, ABN-AMRO Inc. (formerly named The Chicago Corporation, a financial services firm) and Chief Executive Officer, Market Liquidity Network, LLC.		10	Wanger Advisors Trust; First Chicago Bank and Trust; First Chicago Bancorp.
Trustees who are interested persons of Columbia Acorn Trust:
Charles P. McQuaid, 56, Trustee and President(2)		1992	President and Chief Investment Officer, CWAM or its predecessors, since October 2003; associated with CWAM or its predecessors since 1978.		10	Wanger Advisors Trust
Ralph Wanger, 75, Trustee(3)		1970	Founder, CWAM. Formerly, President, Chief Investment Officer and portfolio manager, CWAM or its predecessors, July 1992 – September 2003; Director, Wanger Investment Company PLC; Consultant, CWAM or its predecessors, September 2003 – September 2005.		10	Wanger Advisors Trust
Officers of Columbia Acorn Trust:
Ben Andrews, 43, Vice President		2004	Portfolio manager and analyst, CWAM or its predecessors, since 1998; Vice President, Columbia Acorn Trust and Wanger Advisors Trust since 2004.		10	None
Michael G. Clarke, 40, Assistant Treasurer		2004	Senior Vice President and Chief Financial Officer of certain Columbia Funds since January 2009; Treasurer of certain Columbia Funds from June 2008 – January 2009; Deputy Treasurer of certain Columbia Funds since June 2008; Chief Accounting Officer and Assistant Treasurer, the Columbia Funds, October 2004 to May 2008; Director of Fund Administration, Columbia Management Advisors, LLC, since January 2006; Managing Director, Columbia Management Advisors, LLC, September 2004 – December 2005.		10	None
Jeffrey Coleman, 40, Assistant Treasurer		2006	Treasurer of certain Columbia Funds since June 2008; Director of Fund Administration, CWAM, since January 2006; Fund Controller, CWAM or its predecessors, October 2004 – January 2006.		10	None
P. Zachary Egan, 41, Vice President		2003	Director of International Research, CWAM or its predecessors, since December 2004; Vice President, Columbia Acorn Trust since 2003 and Wanger Advisors Trust since 2007; portfolio manager and analyst, CWAM or its predecessors, since 1999.		10	None
Peter T. Fariel, 52, Assistant Secretary		2006	Associate General Counsel, Bank of America Corporation, since April 2005; prior thereto, Partner, Goodwin Procter LLP (law firm).		10	None

87

Name, Position(s) with Columbia Acorn Trust and Age at December 31, 2009	Year First Elected or Appointed to Office*		Principal Occupation(s) during Past Five Years	Number of Portfolios in Fund Complex Overseen by Trustee/Officer		Other Directorships in addition to Columbia Acorn Trust
Officers of Columbia Acorn Trust: (continued)
John Kunka, 39, Assistant Treasurer		2006	Director of Accounting and Operations, CWAM or its predecessors, since May 2006; Manager of Mutual Fund Operations, Calamos Advisors, Inc. (investment advisor), September 2005 – May 2006; prior thereto, Manager of Mutual Fund Administration, Van Kampen Investments.		10	None
Joseph C. LaPalm, 40, Vice President		2006	Chief Compliance Officer, CWAM since 2005; prior thereto, compliance officer, William Blair & Company (investment firm).		10	None
Bruce H. Lauer, 52, Vice President, Secretary and Treasurer		1995	Chief Operating Officer, CWAM or its predecessors, since April 2000; Vice President, Secretary and Treasurer, Columbia Acorn Trust and Wanger Advisors Trust, since 1995; Director, Wanger Investment Company PLC; Director, Banc of America Capital Management (Ireland) Ltd.; Director, Bank of America Global Liquidity Funds, PLC.		10	None
Louis J. Mendes III, 45, Vice President		2003	Portfolio manager and analyst, CWAM or its predecessors, since 2001; Vice President, Columbia Acorn Trust since 2003 and Wanger Advisors Trust since 2005.		10	None
Robert A. Mohn, 48, Vice President		1997	Director of Domestic Research, CWAM or its predecessors, since March 2004; Vice President, Columbia Acorn Trust and Wanger Advisors Trust, since 1997; portfolio manager and analyst, CWAM or its predecessors, since August 1992.		10	None
Christopher J. Olson, 45, Vice President		2001	Portfolio manager and analyst, CWAM or its predecessors, since January 2001; Vice President, Columbia Acorn Trust and Wanger Advisors Trust, since 2001.		10	None
Robert P. Scales, 57, Chief Compliance Officer, Chief Legal Officer, Senior Vice President and General Counsel		2004	Chief Compliance Officer, Chief Legal Officer, Senior Vice President and General Counsel, Columbia Acorn Trust and Wanger Advisors Trust, since 2004.		10	None
Linda Roth-Wiszowaty, 40, Assistant Secretary		2006	Business support analyst, CWAM, since April 2007; prior thereto executive administrator, CWAM or its predecessors, and executive assistant to the Chief Operating Officer of CWAM or its predecessors.		10	None

*  Dates prior to April 1992 correspond to the date of first election or appointment as a trustee or officers of The Acorn Fund, Inc., the predecessor trust to Columbia Acorn Trust.

(1)  Mr. Kahn retired at the end of calendar year 2009.

(2)  Mr. McQuaid is an "interested person" of Columbia Acorn Trust and of CWAM, as defined in the Investment Company Act of 1940 because he is an officer of the Trust and of CWAM.

(3)  Mr. Wanger is an "interested person" of Columbia Acorn Trust and of CWAM, as defined in the Investment Company Act of 1940 because, as of December 31, 2009, he owned securities issued by a controlling person of CWAM and was a consultant to CWAM within the most recently completed five fiscal years.

88

Columbia Acorn Family of Funds

Fourth Quarter Class Z Share Information

Minimum Initial Investment in all Funds	$2,500 $1,000 for an IRA
Minimum Subsequent Investment in all Funds	$50
Exchange Fee	None

Columbia Acorn Fund	ACRNX
Management Fee	0.65	%
12b-1 Fee	None
Other Expenses	0.12	%
Net Expense Ratio	0.77	%
Columbia Acorn International	ACINX
Management Fee	0.78	%
12b-1 Fee	None
Other Expenses	0.21	%
Net Expense Ratio	0.99	%
Columbia Acorn USA	AUSAX
Management Fee	0.87	%
12b-1 Fee	None
Other Expenses	0.16	%
Net Expense Ratio	1.03	%
Columbia Acorn International Select	ACFFX
Management Fee	0.94	%
12b-1 Fee	None
Other Expenses	0.26	%
Net Expense Ratio	1.20	%
Columbia Acorn Select	ACTWX
Management Fee	0.82	%
12b-1 Fee	None
Other Expenses	0.17	%
Net Expense Ratio	0.99	%
Columbia Thermostat Fund	COTZX
Management Fee	0.10	%
12b-1 Fee	None
Other Expenses	0.15	%*
Net Expense Ratio	0.25	%

    Fees and expenses are for the twelve months ended December 31, 2009, and for Columbia Thermostat Fund include the effect of CWAM's undertaking to waive fees and/or reimburse the Fund for any ordinary operating expenses (exclusive of interest and fees on borrowings, and expenses associated with the Fund's investment in other investment companies, but inclusive of custodian charges relating to overdrafts, if any), after giving effect to any balance credits from the Fund's custodian in excess of the annual rate of 0.25% of the average daily net assets. Columbia Thermostat Fund's reimbursement arrangement is contractual through April 30, 2010.

  *  Does not include estimated fees and expenses of 0.82% incurred by the Fund from the underlying portfolio funds in which it invests.

89

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90

Columbia Acorn Family of Funds

Investment Advisor

Columbia Wanger Asset Management, L.P.
227 West Monroe Street, Suite 3000
Chicago, Illinois 60606

1-800-922-6769

Distributor

Columbia Management Distributors, Inc.
One Financial Center
Boston, Massachusetts 02111-2621

Transfer Agent, Dividend Disbursing Agent

Columbia Management Services, Inc.
P. O. Box 8081
Boston, Massachusetts 02266-8081

1-800-345-6611

Legal Counsel to the Funds

K&L Gates LLP
Washington, DC

Legal Counsel to the Independent Trustees

Drinker Biddle & Reath LLP
Philadelphia, Pennsylvania

Independent Registered Public Accounting Firm

PricewaterhouseCoopers LLP
Chicago, Illinois

This report, including the schedules of investments, is submitted for the general information of the shareholders of Columbia Acorn Trust.

A description of the policies and procedures that the Funds use to determine how to vote proxies and a copy of the Funds' voting record are available (i) without charge, upon request, by calling 800-922-6769 and (ii) on the Securities and Exchange Commission's website at www.sec.gov. Information regarding how the Funds voted proxies relating to portfolio securities during the 12-month period ended June 30, 2009, is available from the SEC's website. Information regarding how the Funds voted proxies relating to portfolio securities is also available at http://institutional.columbiamanagement.com.

The Funds file a complete schedule of portfolio holdings with the SEC for the first and third quarters of each fiscal year on Form N-Q. The Funds' Form N-Q is available on the SEC's website at www.sec.gov and may be reviewed and copied at the SEC's Public Reference Room in Washington, D.C. Information on the operation of the Public Reference Room may be obtained by calling 1-800-SEC-0330. The Funds' complete portfolio holdings are disclosed at www.columbiafunds.com, approximately 30 days after each month-end.

Please read and consider the investment objectives, risks, charges and expenses for any fund carefully before investing. For a prospectus which contains this and other important information about the Fund, contact your Columbia Management representative or financial advisor or go to www.columbiamanagement.com.

Columbia Management Group, LLC ("Columbia Management") is the investment management division of Bank of America Corporation. Columbia Management entities furnish investment management services and products for institutional and individual investors. Columbia Funds are distributed by Columbia Management Distributors, Inc., member of FINRA, SIPC, part of Columbia Management and an affiliate of Bank of America Corporation.

Columbia Wanger Asset Management, L.P. ("CWAM") is a registered investment advisor and an indirect, wholly owned subsidiary of Bank of America Corporation. CWAM is part of Columbia Management.

Find out what's new – visit our web site at:

www.columbiafunds.com

Our e-mail address is:

ServiceInquiries@ColumbiaManagement.com

Shareholders should not include personal information such as account numbers, Social Security numbers or taxpayer identification numbers in e-mail. We are unable to accept account transactions sent via e-mail.

PRESORTED

FIRST-CLASS MAIL

U.S. POSTAGE PAID

HOLLISTON, MA

PERMIT NO. 20

Columbia Management^®

Columbia Acorn Family of Funds

Class Z Shares

Annual Report, December 31, 2009

For More Information

You'll find more information about the Columbia Acorn Family Funds in the documents described below. Contact Columbia Funds as follows to obtain these documents free of charge:

By Mail:  Columbia Funds
c/o Columbia Management Services, Inc.
P.O. Box 8081
Boston, MA 02266-8081

By Telephone: 800.345.6611

Online: www.columbiafunds.com

Shareholder Communications with the Board

The Funds' Board of Trustees has adopted procedures by which shareholders may communicate with the Board. Shareholders who wish to communicate with the Board should send their written communications to the Board by mail, c/o Columbia Wanger Asset Management, L.P., 227 West Monroe Street, Suite 3000, Chicago, Illinois 60606, Attention: Secretary. Shareholder communications must (i)be in writing, (ii) identify the Columbia Acorn Fund to which the communication relates and (iii) state the particular class of shares and number of shares held by the communicating shareholder.

Prospectuses and the Statement of Additional Information (SAI)

The prospectuses and the SAI provide more detailed information about the Funds and their policies. The SAI is legally part of each prospectus (it's incorporated by reference). A copy of each has been filed with the SEC.

Information Provided by the SEC

You can review and copy information about the Funds (including their prospectuses, the SAI and shareholder reports) at the SEC's Public Reference Room in Washington, DC. To find out more about the operation of the Public Reference Room, call the SEC at 202.551.8090. Reports and other information about the Fund are also available in the EDGAR Database on the SEC's website at http://www.sec.gov, or you can receive copies of this information, for a fee, by electronic request at the following e-mail address: publicinfo@sec.gov. You can also obtain copies of this information by writing the Public Reference Section, Securities and Exchange Commission, Washington, DC 20549-0102.

The investment company registration number of Columbia Acorn Trust, of which each of these Funds are a series, is 811-01829.

© 2010 Columbia Management Distributors, Inc.

One Financial Center, Boston, MA 02111-2621

800.345.6611 www.columbiamanagement.com

SHC-42/30222-1209 10/103930

Q4 2009

Columbia Management^®

Columbia Acorn Family of Funds

Class A, B and C Shares

Managed by Columbia Wanger Asset Management, L.P.

Annual Report

December 31, 2009

n  Columbia^SM
Acorn® Fund

n  Columbia^SM
Acorn International®

n  Columbia^SM
Acorn USA®

n  Columbia^SM
Acorn International Select^SM

n  Columbia^SM
Acorn Select^SM

n  Columbia^SM
Thermostat Fund^SM

NOT FDIC INSURED

NOT BANK ISSUED

May Lose Value

No Bank Guarantee

Columbia Acorn Family of Funds

Net Asset Value Per Share as of 12/31/09

	Columbia Acorn Fund		Columbia Acorn International		Columbia Acorn USA		Columbia Acorn International Select		Columbia Acorn Select		Columbia Thermostat Fund
Class A	$	23.98	$	34.13	$	22.43	$	23.39	$	22.81	$	10.90
Class B	$	22.43	$	33.22	$	20.99	$	22.34	$	21.41	$	10.93
Class C	$	22.23	$	33.08	$	20.84	$	22.21	$	21.25	$	10.91

The views expressed in the "Squirrel Chatter II" and "In a Nutshell" commentaries reflect the current views of the respective authors. These views are not guarantees of future performance and involve certain risks, uncertainties and assumptions that are difficult to predict so actual outcomes and results may differ significantly from the views expressed. These views are subject to change at any time based upon economic, market or other conditions and the respective authors disclaim any responsibility to update such views. These views may not be relied upon as investment advice and, because investment decisions for a Columbia Acorn Fund are based on numerous factors, may not be relied upon as an indication of trading intent on behalf of any particular Columbia Acorn Fund. References to specific company securities should not be construed as a recommendation or investment advice and there can be no assurance that as of the date of publication of this report, the securities mentioned in each Fund's portfolio are still held or that the securities sold have not been repurchased.

Letter to Shareholders from the
Columbia Acorn Board of Trustees

Change and Continuity

Fellow Shareholders:

Our Funds enter the New Year facing important governance changes. In the next few months, your Trustees expect that the Fund's investment adviser, Columbia Wanger Asset Management ("CWAM"), will be sold to Ameriprise Financial, Inc. By law, your Trustees must determine whether CWAM should continue to serve as the Funds' investment adviser under its new ownership. Accordingly, the Board has spent significant time and effort considering whether this transaction is in the best interests of shareholders. A specially appointed committee of the Board has reviewed and is negotiating a proposed new investment advisory agreement and contracts with other critical service providers required upon a change of control of the investment adviser. The law also requires that shareholders approve the new investment advisory contract, and proxy materials describing these matters will be sent to shareholders before a change of control takes place.

A second area of change – and continuity – relates to your Funds' Trustees. Sadly, former Chair Bob Nason passed away last June and long-time trustee Jerry Kahn retired at year end. After a transitional period following Bob's death, the Board elected Steve Kaplan as Vice Chair and the undersigned as Chair. I am happy to report that the Board has also elevated Ralph Wanger to "Trustee Emeritus" upon his retirement as a Trustee later this year. This emeritus status allows the Board to continue to benefit from Ralph's experience, insight, and wisdom. Finally, we've rotated the leadership of each of the Board's committees. These changes reflect succession plans put in place by Bob Nason and Allan Muchin (the immediate past Vice Chair) in an effort to preserve the Board's strong independent tradition.

All of your Trustees are, like you, shareholders in the Funds. As such, we were heartened by the recent recovery in the financial markets and the Funds. The domestic Funds did particularly well, exceeding their benchmarks by a significant margin. More importantly, all of the Funds continue to do well when considered over the longer term. Such long-term success remains the constant focus of the Board.

Transitions are rarely easy. That said, your Trustees have worked to identify potential problems and minimize the impact should any arise. In taking these actions, we are following the example of the thoughtful and independent Acorn directors who came before us. They taught your Board to understand and appreciate its role as an unwavering advocate for shareholders and the ultimate protector of the Funds.

Thank you for your trust in the Acorn Funds.

James A. Star
Independent Chairman of the Board of Trustees
Columbia Acorn Trust

Columbia Acorn Family of Funds

Table of Contents

Share Class Performance	1
Fund Performance vs. Benchmarks	2
Description of Indexes	3
Squirrel Chatter II: Skill and Luck	4
Understanding Your Expenses	6
Columbia Acorn Fund
In a Nutshell	8
At a Glance	9
Major Portfolio Changes	20
Statement of Investments	22
Columbia Acorn International
In a Nutshell	10
At a Glance	11
Major Portfolio Changes	34
Statement of Investments	36
Portfolio Diversification	44
Columbia Acorn USA
In a Nutshell	12
At a Glance	13
Major Portfolio Changes	45
Statement of Investments	46
Columbia Acorn International Select
In a Nutshell	14
At a Glance	15
Major Portfolio Changes	54
Statement of Investments	55
Portfolio Diversification	58

Columbia Acorn Select
In a Nutshell	16
At a Glance	17
Major Portfolio Changes	59
Statement of Investments	60
Columbia Thermostat Fund
In a Nutshell	18
At a Glance	19
Statement of Investments	65
Columbia Acorn Family of Funds
Statements of Assets and Liabilities	68
Statements of Operations	69
Statements of Changes in Net Assets	70
Financial Highlights	74
Notes to Financial Statements	80
Report of Independent Registered Public Accounting Firm	89
Federal Income Tax Information	90
Board of Trustees and Management
of Columbia Acorn Funds	91
Columbia Acorn Family of Funds Information	94

No 2009 Year-end Distributions for the Columbia Acorn Funds

Class A, B and C shares of the Columbia Acorn Funds did not have any distributions at year-end.

Bank of America To Sell Columbia Management Group, LLC

On September 29, 2009, Bank of America Corporation entered into an agreement with Ameriprise Financial, Inc. ("Ameriprise") to sell a portion of the long-term asset management business of Columbia Management Group, LLC, including 100% of Columbia Wanger Asset Management, L.P.

The planned acquisition of Columbia Management's long-term asset management business by Ameriprise is subject to federal, state and international regulatory approvals.

Columbia Acorn Family of Funds

Share Class Performance Average Annual Total Returns through 12/31/09

	Class A						Class B*						Class C
	Without Sales Charge			With Sales Charge			Without Sales Charge			With Sales Charge			Without Sales Charge			With Sales Charge
Columbia Acorn Fund (10/16/00)
3 months**		5.69	%		-0.39	%		5.55	%		0.55	%		5.46	%		4.46	%
1 year		39.26	%		31.25	%		38.37	%		33.37	%		38.16	%		37.16	%
3 years		-2.87	%		-4.77	%		-3.47	%		-4.34	%		-3.64	%		-3.64	%
5 years		3.35	%		2.14	%		2.70	%		2.38	%		2.54	%		2.54	%
Life of fund		7.93	%		7.24	%		7.24	%		7.24	%		7.14	%		7.14	%
Columbia Acorn International (10/16/00)
3 months**		4.25	%		-1.75	%		4.07	%		-0.93	%		3.99	%		2.99	%
1 year		50.40	%		41.75	%		49.36	%		44.36	%		49.12	%		48.12	%
3 years		-1.77	%		-3.69	%		-2.37	%		-3.27	%		-2.54	%		-2.54	%
5 years		9.08	%		7.79	%		8.38	%		8.08	%		8.22	%		8.22	%
Life of fund		6.73	%		6.05	%		6.03	%		6.03	%		5.96	%		5.96	%
Columbia Acorn USA (10/16/00)
3 months**		5.95	%		-0.14	%		5.80	%		0.80	%		5.73	%		4.73	%
1 year		41.07	%		32.96	%		40.12	%		35.12	%		39.96	%		38.96	%
3 years		-4.08	%		-5.96	%		-4.70	%		-5.57	%		-4.84	%		-4.84	%
5 years		1.43	%		0.23	%		0.76	%		0.42	%		0.63	%		0.63	%
Life of fund		7.52	%		6.83	%		6.83	%		6.83	%		6.75	%		6.75	%
Columbia Acorn International Select (10/16/00)
3 months**		4.51	%		-1.50	%		4.34	%		-0.66	%		4.32	%		3.32	%
1 year		31.01	%		23.48	%		30.19	%		25.19	%		30.04	%		29.04	%
3 years		-2.80	%		-4.70	%		-3.43	%		-4.33	%		-3.57	%		-3.57	%
5 years		7.62	%		6.35	%		6.93	%		6.62	%		6.77	%		6.77	%
Life of fund		4.25	%		3.58	%		3.55	%		3.55	%		3.48	%		3.48	%
Columbia Acorn Select (10/16/00)
3 months**		7.75	%		1.55	%		7.53	%		2.53	%		7.49	%		6.49	%
1 year		65.65	%		56.13	%		64.44	%		59.44	%		64.22	%		63.22	%
3 years		-2.93	%		-4.83	%		-3.57	%		-4.50	%		-3.73	%		-3.73	%
5 years		3.87	%		2.65	%		3.18	%		2.82	%		3.03	%		3.03	%
Life of fund		7.52	%		6.83	%		6.80	%		6.80	%		6.72	%		6.72	%
Columbia Thermostat Fund (3/3/03)†3 months**		5.62%			-0.45%			5.40%			0.40%			5.41%			4.41%
3 months**		5.62	%		-0.45	%		5.40	%		0.40	%		5.41	%		4.41	%
1 year		31.98	%		24.40	%		31.37	%		26.37	%		30.97	%		29.97	%
3 years		-0.34	%		-2.28	%		-0.84	%		-1.73	%		-1.10	%		-1.10	%
5 years		2.87	%		1.66	%		2.30	%		1.99	%		2.09	%		2.09	%
Life of fund		6.56	%		5.64	%		5.95	%		5.95	%		5.77	%		5.77	%

*The Funds no longer accept investments from new or existing shareholders in Class B shares.

**Not annualized.

Performance data quoted represents past performance and current performance may be lower or higher. Past performance is no guarantee of future results. The investment return and principal value of an investment in a Fund will fluctuate so that Fund shares, when redeemed, may be worth more or less than their original cost. Please visit columbiafunds.com for daily and most recent month-end updates.

The "with sales charge" returns include the maximum initial sales charge of 5.75% for Class A shares, the applicable contingent deferred sales charge (CDSC) for Class B shares (5%, 4%, 3%, 3%, 2%, 1% and 0% for the first through seventh years after purchase, respectively), and the maximum CDSC of 1.00% of Class C shares during the first year after purchase.

Annual operating expense ratios are as stated in each Fund's current prospectus and differences in expense ratios disclosed elsewhere in this report may result from including fee waivers and expense reimbursements as well as different time periods used in calculating the ratios. Columbia Acorn Fund: Class A: 1.05%; Class B: 1.65%; Class C: 1.83%. Columbia Acorn International: Class A: 1.31%; Class B: 1.90%; Class C: 2.08%. Columbia Acorn USA: Class A: 1.29%; Class B: 1.92%; Class C: 2.08%. Columbia Acorn International Select: Class A: 1.54%; Class B: 2.17%; Class C: 2.34%. Columbia Acorn Select: Class A: 1.24%; Class B: 1.87%; Class C: 2.04%. Columbia Thermostat Fund has a contractual expense waiver or reimbursement that expires April 30, 2010. Expense ratios without and with the contractual waiver, including fees and expenses associated with the Fund's investments in other investment companies are: Class A: 1.40%, 1.22%; Class B: 1.92%, 1.72%; Class C: 2.17%, 1.97%, respectively.

Performance results reflect any fee waivers or reimbursements of Fund expenses by the investment advisor and/or any of its affiliates. Absent these fee waivers or expense reimbursement arrangements, performance results would have been lower.

†A "fund of funds" bears its allocable share of the costs and expenses of the underlying funds in which it invests. Such funds are thus subject to two levels of fees and potentially higher expense ratios than would be associated with an investment in a fund that invests and trades directly in financial instruments under the direction of a single manager.

All results shown assume reinvestment of distributions and do not reflect the deduction of taxes that a shareholder would pay on fund distributions or on the redemption of fund shares.

1

Columbia Acorn Family of Funds

Fund Performance vs. Benchmarks Average Annual Total Returns through 12/31/09

Class A Shares, without sales charge	4th quarter*			1 year			3 years			5 years			Life of Fund
Columbia Acorn Fund (LACAX) (10/16/00)		5.69	%		39.26	%		-2.87	%		3.35	%		7.93	%
Russell 2500 Index		5.08	%		34.39	%		-4.86	%		1.58	%		5.24	%
S&P 500 Index**		6.04	%		26.46	%		-5.63	%		0.42	%		-0.40	%
Lipper Small-Cap Core Funds Index		4.49	%		34.50	%		-4.06	%		1.55	%		5.18	%
Lipper Mid-Cap Growth Funds Index		5.65	%		42.65	%		-1.04	%		3.35	%		-1.34	%
Columbia Acorn International (LAIAX) (10/16/00)		4.25	%		50.40	%		-1.77	%		9.08	%		6.73	%
S&P Global Ex-U.S. Between $500 Million and $5 Billion Index		3.46	%		55.49	%		-2.02	%		8.16	%		10.05	%
S&P Global Ex-U.S. SmallCap Index		3.07	%		56.84	%		-4.03	%		7.12	%		9.09	%
MSCI EAFE Index		2.18	%		31.78	%		-6.04	%		3.54	%		3.10	%
Lipper International Small/Mid Growth Funds Index		3.73	%		54.44	%		-4.79	%		7.01	%		4.97	%
Columbia Acorn USA (LAUAX) (10/16/00)		5.95	%		41.07	%		-4.08	%		1.43	%		7.52	%
Russell 2000 Index		3.87	%		27.17	%		-6.07	%		0.51	%		4.28	%
Russell 2500 Index		5.08	%		34.39	%		-4.86	%		1.58	%		5.24	%
S&P 500 Index**		6.04	%		26.46	%		-5.63	%		0.42	%		-0.40	%
Lipper Small-Cap Growth Funds Index		5.29	%		38.04	%		-4.58	%		0.25	%		-0.64	%
Columbia Acorn Int'l Select (LAFAX) (10/16/00)		4.51	%		31.01	%		-2.80	%		7.62	%		4.25	%
S&P Developed Ex-U.S. Between $2 Billion and $10 Billion Index		1.14	%		38.60	%		-6.07	%		4.99	%		7.18	%
MSCI EAFE Index		2.18	%		31.78	%		-6.04	%		3.54	%		3.10	%
Lipper International Funds Index		2.57	%		35.30	%		-4.49	%		4.88	%		3.99	%
Columbia Acorn Select (LTFAX) (10/16/00)		7.75	%		65.65	%		-2.93	%		3.87	%		7.52	%
S&P MidCap 400 Index		5.56	%		37.38	%		-1.83	%		3.27	%		5.44	%
S&P 500 Index**		6.04	%		26.46	%		-5.63	%		0.42	%		-0.40	%
Lipper Mid-Cap Growth Funds Index		5.65	%		42.65	%		-1.04	%		3.35	%		-1.34	%
Columbia Thermostat Fund (CTFAX) (3/3/03)†		5.62	%		31.98	%		-0.34	%		2.87	%		6.56	%
S&P 500 Index		6.04	%		26.46	%		-5.63	%		0.42	%		6.30	%
Barclays Capital U.S. Aggregate Bond Index		0.20	%		5.93	%		6.04	%		4.97	%		4.65	%
Lipper Flexible Portfolio Funds Index		3.97	%		29.17	%		-0.32	%		3.50	%		7.54	%
50/50 Blended Benchmark††		3.13	%		16.34	%		0.52	%		2.99	%		5.76	%

*Not annualized.

**The comparison to the S&P 500 Index is presented to show performance against a widely recognized market index over the life of the Fund.

Performance data quoted represents past performance and current performance may be lower or higher. Past performance is no guarantee of future results. The investment return and principal value of an investment in a Fund will fluctuate so that Fund shares, when redeemed, may be worth more or less than their original cost. Please visit columbiafunds.com for daily and most recent month-end updates.

Annual operating expense ratios are as stated in each Fund's current prospectus and differences in expense ratios disclosed elsewhere in this report may result from including fee waivers and expense reimbursements as well as different time periods used in calculating the ratios. Columbia Acorn Fund: Class A: 1.05%; Class B: 1.65%; Class C: 1.83%. Columbia Acorn International: Class A: 1.31%; Class B: 1.90%; Class C: 2.08%. Columbia Acorn USA: Class A: 1.29%; Class B: 1.92%; Class C: 2.08%. Columbia Acorn International Select: Class A: 1.54%; Class B: 2.17%; Class C: 2.34%. Columbia Acorn Select: Class A: 1.24%; Class B: 1.87%; Class C: 2.04%. Columbia Thermostat Fund has a contractual expense waiver or reimbursement that expires April 30, 2010. Expense ratios without and with the contractual waiver, including fees and expenses associated with the Fund's investments in other investment companies are: Class A: 1.40%, 1.22%; Class B: 1.92%, 1.72%; Class C: 2.17%, 1.97%, respectively.

Performance results reflect any fee waivers or reimbursements of Fund expenses by the investment advisor and/or any of its affiliates. Absent these fee waivers or expense reimbursement arrangements, performance results would have been lower.

†A "fund of funds" bears its allocable share of the costs and expenses of the underlying funds in which it invests. Such funds are thus subject to two levels of fees and potentially higher expense ratios than would be associated with an investment in a fund that invests and trades directly in financial instruments under the direction of a single manager.

††The 50/50 Blended Benchmark is a custom supplemental benchmark established by the advisor.

All results shown assume reinvestment of distributions and do not reflect the deduction of taxes that a shareholder would pay on fund distributions or on the redemption of fund shares.

Unlike mutual funds, indexes are not actively managed and do not incur fees or expenses. It is not possible to invest directly in an index. For index definitions, see Page 3.

The dates in parantheses are the inception dates for each respective Fund.

2

Columbia Acorn Family of Funds

Descriptions of Indexes Included in this Report

•  50/50 Blended Benchmark, established by the Fund's advisor, is an equally weighted custom composite of Columbia Thermostat Fund's primary equity and primary debt benchmarks, the S&P 500 Index and the Barclays Capital 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.

•  Barclays Capital 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.

•  Lipper Indexes include the largest funds tracked by Lipper, Inc. in the named category. Lipper Small-Cap Core Funds Index, 30 largest small-cap core funds; Lipper Mid-Cap Growth Funds Index, 30 largest mid-cap growth funds; Lipper International Small/Mid Growth Funds Index, 10 largest non-U.S. small/mid growth funds, i ncluding Columbia Acorn International; Lipper Small-Cap Growth Funds Index, 30 largest small-cap growth funds; Lipper International Funds Index, 30 largest non-U.S. funds, excluding non-U.S. small-cap funds; Lipper Flexible Portfolio Funds Index, an equal-weighted index of the 30 largest mutual funds within the Flexible Portfolio fund classification, as defined by Lipper.

•  Morgan Stanley Capital International Europe, Australasia, Far East (MSCI EAFE) Index is a capitalization-weighted index that tracks the total return of common stocks in 21 developed-market countries within Europe, Australasia and the Far East.

•  Russell 2000 Index measures the performance of the 2,000 smallest companies in the Russell 3000 Index, which represents approximately 8% of the total market capitalization of the Russell 3000 Index.

•  Russell 2500 Index measures the performance of the 2,500 smallest companies in the Russell 3000 Index, which represents approximately 17% of the total market capitalization of the Russell 3000 Index.

•  Standard & Poor's (S&P) 500 Index tracks the performance of 500 widely held, large-capitalization U.S. stocks.

•  Standard & Poor's (S&P) MidCap 400 Index is a market value-weighted index that tracks the performance of 400 mid-cap U.S.companies.

•  S&P Developed Ex-U.S. Between $2 Billion and $10 Billion Index is a subset of the broad market selected by the index sponsor representing the mid-cap developed market, excluding the United States.

•  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.

•  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 representing the mid- and small-cap developed and emerging markets, excluding the United States.

Unlike mutual funds, indexes are not managed and do not incur fees or expenses. It is not possible to invest directly in an index.

3

Squirrel Chatter II: Skill and Luck

Research has proven that it is extremely difficult for institutional investors to consistently outperform the stock market. The performance distribution among mutual funds usually looks like a bell shaped curve, with some funds outperforming, many underperforming, and the average fund underperforming its benchmark roughly by its expense ratio. I'm happy to say that the Columbia Acorn Funds have historically outperformed their primary benchmark for most time periods, as you can see on Page 2. But researchers note that there are thousands of mutual funds, and purely random outcomes will lead some funds to outperform. This raises an interesting debate: Do funds that outperform do so due to skill, or due to luck?

We try hard to apply investment skills in managing our Funds. We follow a time-tested approach and have an experienced and highly specialized team of investment professionals picking the stocks in which we invest. However, in order to cover both bases, I decided to also read up on luck. Dr. Richard Wiseman's The Luck Factor¹ discusses his research and provides some common sense approaches that may enable people to become luckier.

Wiseman procured hundreds of volunteers, creating one group of people who considered themselves lucky and another who considered themselves unlucky. He tested conventional notions of luck. As one might expect, the lucky group had no apparent psychic ability; their guesses of upcoming lottery numbers were no better than guesses made by the unlucky group. Superstition was not effective either, as the appearance of a black cat vs. a white cat had no impact on results of a coin toss competition.

Instead, Wiseman concluded that people take specific actions that enable them to be lucky and succeed. He provides four principles that induce luck:

1)   Maximize your chance opportunities

2)   Listen to your lucky hunches

3)   Expect good fortune

4)   Turn bad luck into good

Though Wiseman does not explicitly mention investing, each principle can be applied in pursuit of successful money management.

Maximizing chance opportunities entails meeting a large number of people and creating networks to obtain information and investment ideas. Being observant and open to new ideas also helps. Successful investments can be discovered inadvertently: years ago I observed long lines and rising prices at parking garages in downtown Chicago and then profitably invested in a parking lot stock. Rather than pursuing information in hope of confirming existing opinions, pursuing unbiased information could induce the sale of an existing stock and purchase of a superior new one.

Listening to lucky hunches requires the use of intuition. Stocks tend to quickly react to information, and acting early, using imperfect information, is indeed an art form. We once had an analyst who tended to act only after obtaining repeated confirmations that company fundamentals had changed. He performed poorly because stocks often moved before he acted. In contrast, we recently successfully invested in a telecommunications stock that appeared likely to rise as an increasing number of Wall Street analysts began following it. Occasionally, we choose not to pursue possible investment opportunities because they simply don't feel right.

The next luck-inducing principle is to expect good fortune. This is consistent with our investment philosophy. We put money into stocks with the expectation that they will make money over time. We tend to expect continued good fortune from our successful investments and, when it makes sense, let our winners run. This has resulted in lower turnover than the industry average for the Columbia Acorn Funds.

We also attempt to turn bad luck into good and pursue an occasional positive side of bad luck. In the 1980s, several of our analysts complained about aggressive foreign competitors hurting companies we held in Columbia Acorn Fund. The portfolio manager at that time, Ralph Wanger, coined the phrase, "Don't bitch, switch!" and we've owned some foreign stocks in Acorn Fund ever since. We've learned that one company's problem may be

4

another company's opportunity, and that the best choice may be to invest in the latter company.

Ben Sherwood's The Survivors Club² also mentions a few attributes applicable to investing. Situational awareness is a key part of military survival training and is important in investing too. Although many homebuilding stocks looked cheap during the housing bubble, generally avoiding them benefited our shareholders. Likewise, a well-run company may perform well within a highly competitive industry, but its stock could have substantial downside if its management changes or it grows beyond its niche.

As defined by Sherwood, the "incredulity response" occurs when very unusual events occur, such as catastrophes. Market meltdowns also appear to qualify. People tend to not believe such an event is happening and become paralyzed. Instead, survivors need to act positively. During a market meltdown, the market becomes extremely risk averse, and pays investors handsomely to take risk. That was true a year ago and we invested in several companies with substantial debt that our analysis indicated would likely survive and flourish. On average, those stocks performed very well for shareholders.

Both authors believe that people can create their own luck. After reading their perspectives, I have to agree. We at Columbia Wanger Asset Management think that creating luck is a skill and that providing above average returns is no random act.

Charles P. McQuaid

President and Chief Investment Officer
Columbia Wanger Asset Management, L.P.

The information and data provided in this analysis are derived from sources that we deem to be reliable and accurate. These views are not guarantees of future performance and involve certain risks, uncertainties and assumptions that are difficult to predict so actual outcomes and results may differ significantly from the views expressed. The views/opinions expressed in "Squirrel Chatter II" are those of the author and not of the Columbia Acorn Trust Board, are subject to change at any time based upon economic, market or other conditions, may differ from views expressed by other Columbia Management associates or other divisions of Bank of America and the respective parties disclaim any responsibility to update such views. These views may not be relied on as investment advice and, because investment decisions for a Columbia Acorn Fund are based on numerous factors, may not be relied on as an indication of trading intent on beha lf of any particular Columbia Acorn Fund.

Stocks of small- and mid-cap companies pose special risks, including possible illiquidity and greater price volatility than stocks of larger, more established companies. International investing involves special risks, including foreign taxation, currency risks, risks associated with possible differences in financial standards and other risks associated with future political and economic developments. Investing in emerging markets may involve greater risks than investing in more developed countries. In addition, concentration of investments in a single region may result in greater volatility. A fund that maintains a relatively concentrated portfolio may be subject to greater risk than a fund that is more fully diversified.

¹  Wiseman, Richard, The Luck Factor, (New York, New York, Miramax Books/Hyperion 2003).

²  Sherwood, Ben, The Survivors Club, (New York, New York, Grand Central Publishing, 2009).

Also referenced in the writing of this essay was a research paper written by Eugene F. Fama and Kenneth R. French titled, "Luck versus Skill in the Cross Section of Mutual Fund Returns." The paper was originally dated October 2007 and updated in November 2009. It can be found on the Social Science Research Network's website at www.ssrn.com.

5

Understanding Your Expenses

As a Fund shareholder, you incur two types of costs. There are transaction costs, which generally include sales charges on purchases and may include redemption or exchange fees. There are also ongoing costs, which generally include investment advisory fees, distribution and service (Rule 12b-1) fees and other Fund expenses. The following information is intended to help you understand your ongoing costs of investing in the Columbia Acorn Funds and to compare these costs with the ongoing costs of investing in other mutual funds.

Analyzing Your Fund's Expenses

To illustrate these ongoing costs, we have provided examples and calculated the expenses paid by investors in the Class A, B and C shares of the Columbia Acorn Funds for the last six months. The information in the following table is based on an initial investment of $1,000, which is invested at the beginning of the reporting period and held for the entire period. Expense information is calculated two ways and each method provides you with different results. The amount listed in the "Actual" column is calculated using each Fund's actual operating expenses and total return for the period. The amount listed in the "Hypothetical" column assumes that the return each year is 5% before expenses and then applies each Fund's actual expense ratio for the period to the hypothetical return. You should not use the hypothetical account values and expenses to estimate either your actual account balance at the end of the period or the expenses you paid during the reporting period. See "Compare With Other Funds" for details on using the hypothetical data.

July 1, 2009 – December 31, 2009

	Account value at the beginning of the period ($)				Account value at the end of the period ($)				Expenses paid during the period ($)				Fund's annualized expense ratio (%)*
	Actual		Hypothetical		Actual		Hypothetical		Actual		Hypothetical		Actual
Columbia Acorn Fund
Class A		1,000.00		1,000.00		1,270.10		1,020.01		5.89		5.24		1.03
Class B		1,000.00		1,000.00		1,266.50		1,016.74		9.60		8.54		1.68
Class C		1,000.00		1,000.00		1,265.20		1,015.88		10.56		9.40		1.85
Columbia Acorn International
Class A		1,000.00		1,000.00		1,242.40		1,018.65		7.35		6.61		1.30
Class B		1,000.00		1,000.00		1,238.60		1,015.58		10.78		9.70		1.91
Class C		1,000.00		1,000.00		1,237.10		1,014.67		11.78		10.61		2.09
Columbia Acorn USA
Class A		1,000.00		1,000.00		1,307.10		1,018.70		7.50		6.56		1.29
Class B		1,000.00		1,000.00		1,302.90		1,015.43		11.26		9.86		1.94
Class C		1,000.00		1,000.00		1,301.70		1,014.72		12.07		10.56		2.08
Columbia Acorn International Select
Class A		1,000.00		1,000.00		1,198.30		1,017.34		8.64		7.93		1.56
Class B**		1,000.00		1,000.00		1,194.00		1,014.12		12.17		11.17		2.20
Class C		1,000.00		1,000.00		1,192.80		1,013.11		13.26		12.18		2.40

6

	Account value at the beginning of the period ($)				Account value at the end of the period ($)				Expenses paid during the period ($)				Fund's annualized expense ratio (%)*
	Actual		Hypothetical		Actual		Hypothetical		Actual		Hypothetical		Actual
Columbia Acorn Select
Class A		1,000.00		1,000.00		1,334.70		1,019.06		7.18		6.21		1.22
Class B		1,000.00		1,000.00		1,329.80		1,015.48		11.33		9.80		1.93
Class C		1,000.00		1,000.00		1,328.10		1,014.77		12.15		10.51		2.07
Columbia Thermostat Fund**
Class A		1,000.00		1,000.00		1,227.50		1,022.68		2.81		2.55		0.50
Class B		1,000.00		1,000.00		1,224.00		1,020.16		5.61		5.09		1.00
Class C		1,000.00		1,000.00		1,223.10		1,018.90		7.00		6.36		1.25

Expenses paid during the period are equal to each Fund's annualized expense ratio, multiplied by the average account value over the period and then multiplied by the number of days in the Fund's most recent fiscal half-year and divided by 365.

It is important to note that the expense amounts shown in the table are meant to highlight only ongoing costs of investing in the Funds and do not reflect any transaction costs, such as sales charges or redemption or exchange fees. Therefore, the hypothetical examples provided may not help you determine the relative total costs of owning different funds. If these transaction costs were included, your costs would have been higher.

Columbia Thermostat Fund's expenses do not include fees and expenses incurred by the Fund from the underlying portfolio funds in which it invests.

*For the six months ended December 31, 2009.

**Had the investment advisor and/or any of its affiliates not waived fees or reimbursed a portion of expenses, account value at the end of the period would have been reduced.

Compare With Other Funds

Since all mutual funds are required to include the same hypothetical calculations about expenses in shareholder reports, you can use this information to compare the ongoing cost of investing in the Funds with other funds. To do so, compare the 5% hypothetical example with the 5% hypothetical examples that appear in the shareholder reports of other funds. As you compare hypothetical examples of other funds, it is important to note that hypothetical examples are meant to highlight the continuing costs of investing in a fund and do not reflect any transaction costs, such as sales charges or redemption or exchange fees.

Estimating Your Actual Expenses

To estimate the expenses that you actually paid over the period, first you will need your account balance at the end of the period:

•For shareholders who receive their account statements from Columbia Management Services, Inc., your account balance is available online at columbiafunds.com or by calling Shareholder Services at (800) 922-6769.

•For shareholders who receive their account statements from their brokerage firm, contact your brokerage firm to obtain your account balance.

1.  Divide your ending account balance by $1,000. For example, if an account balance was $8,600 at the end of the period, the result would be 8.6.

2.  In the section of the table titled "Expenses paid during the period," locate the amount for your Fund. You will find this number is in the column labeled "Actual." Multiply this number by the result from step 1. Your answer is an estimate of the expenses you paid on your account during the period.

7

Columbia Acorn Fund

In a Nutshell

Charles P. McQuaid	Robert A. Mohn
Lead Portfolio Manager	Co-Portfolio Manager

Performance data quoted represents past performance and current performance may be lower or higher. Past performance is no guarantee of future results. The investment return and principal value will fluctuate so that shares, when redeemed, may be worth more or less than the original cost. Please visit columbiafunds.com for daily and most recent month-end performance updates.

Fund Positions
in Mentioned Holdings

As a percentage of net assets,
as of 12/31/09

Crown Castle International	1.7	%
Coach	1.5	%
FMC Technologies	1.2	%
tw telecom	1.1	%
Fugro	1.1	%
Southwestern Energy	1.0	%
Urban Outfitters	1.0	%
Chico's FAS	0.8	%
Atwood Oceanics	0.8	%
J Crew Group	0.8	%
Valley National Bancorp	0.5	%
Pacific Rubiales Energy	0.5	%
Illumina	0.4	%
MB Financial	0.3	%
Associated Banc-Corp	0.3	%

Columbia Acorn Fund jumped 39.26% (Class A shares, without sales charge) in 2009, 4.87% above its primary benchmark, the Russell 2500 Index. During the fourth quarter, the Fund appreciated 5.69%, modestly more than the Russell 2500's 5.08% gain. Additional performance comparisons can be found on Page 2 of this report.

Energy stocks were important contributors to the Fund's performance for the year and the quarter. Offshore oil service providers FMC Technologies, Fugro and Atwood Oceanics all more than doubled during the year on strong revenues and volumes. Oil and gas producers Southwestern Energy and Pacific Rubiales Energy provided 13% and 19% returns in the fourth quarter due to increased production, while XTO Energy rose 16% as its acquisition by Exxon Mobil was announced in December. We sold the Fund's XTO shares on the news.

Telecom stocks were also strong performers. Communications tower company Crown Castle International provided the Fund's largest dollar gains during both periods on a 122% surge for the year, including a 24% gain in the fourth quarter. We had added to holdings in Crown Castle during the credit crunch in late 2008, correctly believing in the company's business model and its ability to service a fairly large debt load. Provider of fiber optic telephone and data services tw telecom doubled during the year and gained 27% in the quarter as its business model proved to be fairly resistant to the recession.

After a tough 2008, retailers cashed in big gains in 2009. J Crew Group more than tripled and Urban Outfitters more than doubled on fine earnings due to strong product lines, market share gains and expense controls. Chico's FAS stock jumped 268% as new management executed a turnaround plan. Handbag designer and marketer Coach bagged a 77% gain for the year as management continued to execute well. All were up between 8% and 25% during the fourth quarter.

As might be expected given its overall results, Columbia Acorn Fund had few large losers in 2009. In the financials sector, Associated Banc-Corp was the largest dollar loser, falling 46% on large credit losses, while MB Financial and Valley National Bancorp fell about half that percentage for much the same reason. While we hate any losses, the Fund's aggregate bank holdings fell 5% in the year, much less than the loss of 22% in the benchmark's bank portfolio. During the quarter, Illumina, a maker of medical devices, was the largest dollar loser, off 28% on a revenue shortfall.

Columbia Acorn Fund's foreign stocks were up 76.73% for the year and 6.84% for the fourth quarter. The foreign portfolio has relatively large weights in energy and materials companies, which have done well. Fugro and Pacific Rubiales Energy, mentioned above, were the top international contributors. At year-end, international stocks made up 11.1% of the Fund.

We spent much of the last 15 months dealing with a volatile stock market and a weak economy. Understanding that smaller caps and more risky stocks have historically tended to recover the most off a deep market bottom, we prudently pursued them. Many of those investments were successful, and now we are pursuing companies that we expect to have good earnings growth. While we are happy with 2009 and fourth quarter performance, we realize that we have still not returned to the Fund's 2008 highs.

Stocks of small- and mid-cap companies pose special risks, including possible illiquidity and greater price volatility than stocks of larger, more established companies. International investing involves special risks, including foreign taxation, currency risks, risks associated with possible differences in financial standards and other risks associated with future political and economic developments.

Portfolio holdings are subject to change periodically and may not be representative of current holdings.

8

Columbia Acorn Fund (LACAX)

At a Glance

Performance data quoted represents past performance and current performance may be higher or lower. Past performance is no guarantee of future results. The investment return and principal value of an investment in the Fund will fluctuate so that Fund shares, when redeemed, may be worth more or less than their original cost. Performance results reflect any fee waivers or reimbursements of Fund expenses by the investment advisor and/or any of its affiliates. Absent these fee waivers or expense reimbursement arrangements, performance results would have been lower. Please visit columbiafunds.com for daily and most recent month-end updates.

Pretax and After-tax Average Annual Total Returns (Based on Class A Share Returns)

through December 31, 2009

Inception 10/16/00		1 year	5 years	Life of fund
Returns before taxes	NAV POP	39.26% 31.25	3.35% 2.14	7.93% 7.24
Returns after taxes on distributions	NAV POP	39.26 31.25	2.62 1.41	7.13 6.44
Returns after taxes on distributions and sale of fund shares	NAV POP	25.52 20.31	2.92 1.87	6.83 6.20
Russell 2500 Index (pretax)*		34.39	1.58	5.24

All results shown assume reinvestment of distributions.

*The Fund's primary benchmark.

After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect the impact of state and local taxes. Returns after taxes on distributions and sale of Fund shares reflect the additional tax impact of long-term gains or losses realized when Fund shares are sold. The returns are taxed at the maximum rate and assume shares were purchased at the beginning of the period. Actual after-tax returns depend on the investor's tax situation and may differ from those shown. After-tax returns are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts. After-tax returns are shown for Class A shares only; after-tax returns for other share classes will vary. Indexes do not reflect any deduction for fees, expenses or taxes. Investment returns and principal value may fluctuate, resulting in a gain or loss on sale.

Public offering price (POP) returns include the maximum sales charge of 5.75% for Class A shares. Net asset value (NAV) returns do not include sales charges or contingent deferred sales charges (CDSC).

The Fund's Class A shares annual operating expense ratio, as stated in the current prospectus, is 1.05%.

Columbia Acorn Fund Portfolio Diversification

as a percentage of net assets, as of 12/31/09

Columbia Acorn Fund Top 10 Holdings

as a percentage of net assets, as of 12/31/09

1.	Crown Castle International Communications Towers	1.7%
2.	Coach Designer & Retailer of Branded Leather Accessories	1.5%
3.	Informatica Enterprise Data Integration Software	1.2%
4.	FMC Technologies Oil & Gas Wellhead Manufacturer	1.2%
5.	Donaldson Industrial Air Filtration	1.2%
6.	Amphenol Electronic Connectors	1.2%
7.	Ametek Aerospace/Industrial Instruments	1.2%
8.	Bally Technologies Slot Machines & Software	1.1%
9.	tw telecom Fiber Optic Telephone/Data Services	1.1%
10.	Fugro (Netherlands) Sub-sea Oilfield Services	1.1%

The Fund's top 10 holdings and portfolio diversification vary with changes in portfolio investments. See the Statement of Investments for a complete list of the Fund's holdings.

The Growth of a $10,000 Investment in Columbia Acorn Fund (Class A)

October 16, 2000 through December 31, 2009

Illustration is based on a hypothetical $10,000 investment from inception in Class A shares of the Fund, which includes a 5.75% maximum initial sales charge. The Russell 2500 Index is unmanaged and returns for both the index and the Fund include reinvested dividends and capital gains. Although the index is provided for use in assessing the Fund's performance, the Fund's holdings may differ significantly from those in the index. It is not possible to invest directly in an index. The graph does not reflect taxes that a shareholder would pay on Fund distributions or on a sale of Fund shares.

Total Net Assets of the Fund: $14.7 billion

9

Columbia Acorn International

In a Nutshell

P. Zachary Egan	Louis J. Mendes III
Co-Portfolio Manager	Co-Portfolio Manager

Performance data quoted represents past performance and current performance may be lower or higher. Past performance is no guarantee of future results. The investment return and principal value will fluctuate so that shares, when redeemed, may be worth more or less than the original cost. Please visit columbiafunds.com for daily and most recent month-end performance updates.

Fund's Positions
in Mentioned Holdings

As a percentage of net assets,
as of 12/31/09

Naspers	1.8	%
Seven Bank	0.5	%
Wacom	0.4	%

Columbia Acorn International returned 4.25% (Class A shares, without sales charge) in the fourth quarter of 2009, 0.79% ahead of its primary benchmark, the S&P Global Ex-U.S. Between $500 Million and $5 Billion Index. The Fund's annual total return of 50.40% trailed its benchmark by 5.09%. Across most markets, share price performance was negatively correlated with size as smaller-capitalized stocks outperformed their larger brethren. The large-cap MSCI EAFE Index returned a relatively modest 31.78%.

We manage Columbia Acorn International with the intention of holding Fund investments for three- to five-years, which is relatively long among international small-cap managers. We believe Fund performance should be considered in this context. A glance at the performance table on Page 2 shows that the Fund's three- and five-year average annual returns were -1.77% and 9.08%, respectively. Both results remain ahead of Fund benchmarks and peer averages.

Much has been written in the financial press about the equity market's return from the precipice after a difficult January and February in 2009. We will not reproduce that discussion here, other than to note that the market rebound generally played out in a fashion consistent with a sudden subsidence of risk aversion across the board. The riskiest equities, including illiquid micro-caps, highly indebted companies and emerging market stocks, led the charge upward. In contrast, lower-risk markets such as Japan, where stocks are cheap, balance sheets overcapitalized and growth expectations generally too anemic to provide cause for disappointment, barely moved. Japanese small- to mid-cap stocks rose a mere 5.6% in U.S. dollar terms in 2009. In this context, it is interesting to look at the winning and losing stocks in the Fund whose performance cannot be explained by changes in how risk is priced alone. This highlights where stock p icking matters.

Fund standouts on the upside included Naspers and Wacom. Naspers is a misunderstood South African-listed media company. With a dominant pay TV franchise in sub-Saharan Africa and a large stake in Tencent, a Hong Kong-listed Internet service provider and gaming company targeting the Chinese market, many investors have been unsure how to analyze the company. Our colleague Fritz Kaegi ferreted out this South African company, which more than doubled in the year and is now the Fund's largest position. Wacom is a Japanese technology company that jumped 155% in 2009 when demand for its pen tablet for professional and consumer applications proved resilient in a weak IT market. The company's new multi-finger touch screen for PCs also has a chance of playing an important role in the next generation of PC user interfaces.

On the downside, the Fund sold its investment in ING Bank Slaski at a 52% annual loss after wrongly judging that the Polish government would intervene in the currency market. This intervention would have let corporations off the hook on costly forward contracts they held with Polish banks. Japanese cash machine network operator Seven Bank, which operates ATMs at convenience stores, ended the year down 47% as investors worried that deflation expectations and weak consumer spending would reduce cash withdrawals and new consumer finance regulations would constrain high margin lending on ATM cards.

International investing may involve certain risks, including currency fluctuations, risks associated with possible differences in financial standards and other monetary and political risks. Significant levels of foreign taxes, including potentially confiscatory levels of taxation and withholding taxes, may also apply to some foreign investments. Stocks of small- and mid-cap companies pose special risks, including possible illiquidity and greater price volatility than stocks of larger, more established companies. Investing in emerging markets may involve greater risks than investing in more developed countries. In addition, concentration of investments in a single region may result in greater volatility.

Portfolio holdings are subject to change periodically and may not be representative of current holdings.

10

Columbia Acorn International (LAIAX)

At a Glance

Performance data quoted represents past performance and current performance may be higher or lower. Past performance is no guarantee of future results. The investment return and principal value of an investment in the Fund will fluctuate so that Fund shares, when redeemed, may be worth more or less than their original cost. Performance results reflect any fee waivers or reimbursements of Fund expenses by the investment advisor and/or any of its affiliates. Absent these fee waivers or expense reimbursement arrangements, performance results would have been lower. Please visit columbiafunds.com for daily and most recent month-end updates.

Pretax and After-tax Average Annual Total Returns (Based on Class A Share Returns)

through December 31, 2009

Inception 10/16/00		1 year	5 years	Life of fund
Returns before taxes	NAV POP	50.40% 41.75	9.08% 7.79	6.73% 6.05
Returns after taxes on distributions	NAV POP	49.63 41.02	8.25 6.97	5.97 5.29
Returns after taxes on distributions and sale of fund shares	NAV POP	32.66 27.05	7.91 6.77	5.76 5.15
S&P Global Ex-U.S. Between $500 Million and $5 Billion Index (pretax)*		55.49	8.16	10.05

All results shown assume reinvestment of distributions.

*The Fund's primary benchmark.

After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect the impact of state and local taxes. Returns after taxes on distributions and sale of Fund shares reflect the additional tax impact of long-term gains or losses realized when Fund shares are sold. The returns are taxed at the maximum rate and assume shares were purchased at the beginning of the period. Actual after-tax returns depend on the investor's tax situation and may differ from those shown. After-tax returns are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts. After-tax returns are shown for Class A shares only; after-tax returns for other share classes will vary. Indexes do not reflect any deduction for fees, expenses or taxes. Investment returns and principal value may fluctuate, resulting in a gain or loss on sale.

Public offering price (POP) returns include the maximum sales charge of 5.75% for Class A shares. Net asset value (NAV) returns do not include sales charges or contingent deferred sales charges (CDSC).

The Fund's Class A shares annual operating expense ratio, as stated in the current prospectus, is 1.31%.

Columbia Acorn International Portfolio Diversification

as a percentage of net assets, as of 12/31/09

Columbia Acorn International Top 10 Holdings

as a percentage of net assets, as of 12/31/09

1.	Naspers (South Africa) Media in Africa & Other Emerging Markets	1.8%
2.	Olam International (Singapore) Agriculture Supply Chain Manager	1.5%
3.	Eldorado Gold (Canada) Gold Miner in Turkey, Greece, China & Brazil	1.3%
4.	Serco (United Kingdom) Facilities Management	1.2%
5.	Localiza Rent A Car (Brazil) Car Rental	1.2%
6.	Hexagon (Sweden) Measurement Equipment	1.2%
7.	Kansai Paint (Japan) Paint Producer in Japan, India, China & Southeast Asia	1.2%
8.	Imtech (Netherlands) Electromechanical & ICT Installation & Maintenance	1.1%
9.	Suzano (Brazil) Brazilian Pulp & Paper Producer	1.1%
10.	Atwood Oceanics (United States) Offshore Drilling Contractor	1.1%

The Fund's top 10 holdings and portfolio diversification vary with changes in portfolio investments. See the Statement of Investments for a complete list of the Fund's holdings.

The Growth of a $10,000 Investment in Columbia Acorn International (Class A)

October 16, 2000 through December 31, 2009

Illustration is based on a hypothetical $10,000 investment from inception in Class A shares of the Fund, which includes a 5.75% maximum initial sales charge. The S&P Global Ex-U.S. Between $500 Million and $5 Billion Index is unmanaged and returns for both the index and the Fund include reinvested dividends and capital gains. Although the index is provided for use in assessing the Fund's performance, the Fund's holdings may differ significantly from those in the index. It is not possible to invest directly in an index. The graph does not reflect taxes that a shareholder would pay on Fund distributions or on a sale of Fund shares.

Total Net Assets of the Fund: $4.4 billion

11

Columbia Acorn USA

In a Nutshell

Robert A. Mohn

Lead Portfolio Manager

Performance data quoted represents past performance and current performance may be lower or higher. Past performance is no guarantee of future results. The investment return and principal value will fluctuate so that shares, when redeemed, may be worth more or less than the original cost. Please visit columbiafunds.com for daily and most recent month-end performance updates.

Fund Positions
in Mentioned Holdings

As a percentage of net assets,
as of 12/31/09

Crown Castle International	3.5	%
tw telecom	2.5	%
FMC Technologies	2.1	%
Atwood Oceanics	1.9	%
AmeriCredit	1.6	%
Donaldson	1.4	%
ITT Educational Services	1.3	%
World Acceptance	1.1	%
Valley National Bancorp	1.0	%
Switch & Data Facilities	0.7	%
MB Financial	0.7	%
Human Genome Sciences	0.7	%
Lakeland Financial	0.5	%
Pacific Continental	0.4	%
True Religion Apparel	0.4	%
Berkshire Hills Bancorp	0.4	%
Illumina	0.3	%
Psychiatric Solutions	0.3	%
Cephalon	0.3	%
Associated Banc-Corp	0.2	%

Columbia Acorn USA ended the fourth quarter of 2009 up 5.95% (Class A shares, without sales charge), outperforming the 3.87% gain of its primary benchmark, the Russell 2000 Index. For the year, the Fund strongly outperformed the Russell 2000 with a 41.07% return vs. a 27.17% annual gain for the index. While we are happy with 2009 performance, we realize that we have still not returned to the Fund's 2008 highs.

Fund telecommunication stocks continued to perform well in the fourth quarter. Both Crown Castle International, an owner of communications towers, and tw telecom, a provider of fiber optic telephone and data services, had solid revenue growth despite the Great Recession. These stocks both were up roughly 25% for the quarter and ended the year up over 100%.

Our holdings of companies in the consumer finance sector were also strong in the quarter as these stocks benefited from the disappearance of many of their competitors. World Acceptance, a provider of smaller personal loans, saw its earnings grow 48% year-over-year through September and announced a decrease in credit losses. Its stock gained 42% in the fourth quarter. Several large banks have completely withdrawn from the business of making used auto loans, and this reduction in supply has contributed to boosted lending spreads for surviving lenders such as AmeriCredit. AmeriCredit enjoyed a 21% gain in the fourth quarter and ended the year up 149%.

Biotech company Human Genome Sciences continued its strong run in the fourth quarter, posting a 62% gain after announcing additional positive results from its lupus drug trials. Its annual gain was a whopping 840%. Switch & Data Facilities, a provider of data center and Internet exchange services, gained 49% in the quarter and 179% for the year on news that it would be acquired by Equinix, a provider of data center operations and infrastructure services. Donaldson, a maker of industrial air filters, gained 23% in the quarter as the company controlled costs and increased its market share.

Top contributors to the Fund's annual performance were energy stocks FMC Technologies, an oil and gas wellhead manufacturer, and Atwood Oceanics, an offshore drilling contractor. Both had annual gains of over 140% as the industry's focus on deep sea drilling fueled growth in their businesses.

On the downside for the quarter, ITT Educational Services, a provider of post-secondary degree programs, fell 13% as student debt defaults showed signs of increasing. Premium denim retailer True Religion Apparel and Illumina, a maker of medical devices, reported disappointing third quarter sales, sending both companies' stocks down roughly 28%. Psychiatric Solutions, a provider of behavioral health services, fell 23% in the quarter and 26% for the year. Its business was hurt by an increase in the percentage of its patients who were uninsured.

Six of the 15 biggest detractors to performance in the Fund for the year were regional banks. MB Financial, Valley National Bancorp, Lakeland Financial, Berkshire Hills Bancorp, Associated Banc-Corp and Pacific Continental were all down between 22% and 46%. Losses on commercial loans held by these banks accelerated throughout the year, particularly on loans tied to new residential developments. Another laggard for the year was pharmaceutical company Cephalon, which was off nearly 20% in the Fund. Several of Cephalon's drug patents will expire soon, making way for competition from generics.

This past year started off with tremendous uncertainty but we were able to take advantage of the volatility in the market to make some opportunistic purchases of beaten down stocks. As we move into a new year, we plan to focus on finding stocks in smaller, niche companies, which we believe have good growth prospects and trade at attractive prices.

Stocks of small- and mid-cap companies pose special risks, including possible illiquidity and greater price volatility than stocks of larger, more established companies.

Portfolio holdings are subject to change periodically and may not be representative of current holdings.

12

Columbia Acorn USA (LAUAX)

At a Glance

Performance data quoted represents past performance and current performance may be higher or lower. Past performance is no guarantee of future results. The investment return and principal value of an investment in the Fund will fluctuate so that Fund shares, when redeemed, may be worth more or less than their original cost. Performance results reflect any fee waivers or reimbursements of Fund expenses by the investment advisor and/or any of its affiliates. Absent these fee waivers or expense reimbursement arrangements, performance results would have been lower. Please visit columbiafunds.com for daily and most recent month-end updates.

Pretax and After-tax Average Annual Total Returns (Based on Class A Share Returns)

through December 31, 2009

Inception 10/16/00		1 year	5 years	Life of fund
Returns before taxes	NAV POP	41.07% 32.96	1.43% 0.23	7.52% 6.83
Returns after taxes on distributions	NAV POP	41.07 32.96	0.92 -0.27	7.19 6.51
Returns after taxes on distributions and sale of fund shares	NAV POP	26.69 21.42	1.27 0.25	6.65 6.03
Russell 2000 Index (pretax)*		27.17	0.51	4.28

All results shown assume reinvestment of distributions.

*The Fund's primary benchmark.

After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect the impact of state and local taxes. Returns after taxes on distributions and sale of Fund shares reflect the additional tax impact of long-term gains or losses realized when Fund shares are sold. The returns are taxed at the maximum rate and assume shares were purchased at the beginning of the period. Actual after-tax returns depend on the investor's tax situation and may differ from those shown. After-tax returns are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts. After-tax returns are shown for Class A shares only; after-tax returns for other share classes will vary. Indexes do not reflect any deduction for fees, expenses or taxes. Investment returns and principal value may fluctuate, resulting in a gain or loss on sale.

Public offering price (POP) returns include the maximum sales charge of 5.75% for Class A shares. Net asset value (NAV) returns do not include sales charges or contingent deferred sales charges (CDSC).

The Fund's Class A shares annual operating expense ratio, as stated in the current prospectus, is 1.29%.

Columbia Acorn USA Portfolio Diversification

as a percentage of net assets, as of 12/31/09

Columbia Acorn USA Top 10 Holdings

as a percentage of net assets, as of 12/31/09

1.	Crown Castle International Communications Towers	3.5%
2.	tw telecom Fiber Optic Telephone/Data Services	2.5%
3.	Informatica Enterprise Data Integration Software	2.1%
4.	FMC Technologies Oil & Gas Wellhead Manufacturer	2.1%
5.	Atwood Oceanics Offshore Drilling Contractor	1.9%
6.	Global Payments Credit Card Processor	1.8%
7.	Ametek Aerospace/Industrial Instruments	1.7%
8.	Bally Technologies Slot Machines & Software	1.7%
9.	Nordson Dispensing Systems for Adhesives & Coatings	1.6%
10.	AmeriCredit Auto Lending	1.6%

The Fund's top 10 holdings and portfolio diversification vary with changes in portfolio investments. See the Statement of Investments for a complete list of the Fund's holdings.

The Growth of a $10,000 Investment in Columbia Acorn USA (Class A)

October 16, 2000 through December 31, 2009

Illustration is based on a hypothetical $10,000 investment from inception in Class A shares of the Fund, which includes a 5.75% maximum initial sales charge. The Russell 2000 Index is unmanaged and returns for both the index and the Fund include reinvested dividends and capital gains. Although the index is provided for use in assessing the Fund's performance, the Fund's holdings may differ significantly from those in the index. It is not possible to invest directly in an index. The graph does not reflect taxes that a shareholder would pay on Fund distributions or on a sale of Fund shares.

Total Net Assets of the Fund: $1.4 billion

13

Columbia Acorn International Select

In a Nutshell

Christopher J. Olson

Lead Portfolio Manager

Performance data quoted represents past performance and current performance may be lower or higher. Past performance is no guarantee of future results. The investment return and principal value will fluctuate so that shares, when redeemed, may be worth more or less than the original cost. Please visit columbiafunds.com for daily and most recent month-end performance updates.

Fund's Positions
in Mentioned Holdings

As a percentage of net assets,
as of 12/31/09

Naspers	6.2	%
Ascendas REIT	2.9	%
Hexagon	2.4	%
Pacific Rubiales Energy	2.2	%
Jupiter Telecommunications	2.2	%
Potash Corp. of Saskatchewan	2.1	%
Benesse	1.9	%
Rohto Pharmaceutical	1.8	%
Seven Bank	1.7	%
Ain Pharmaciez	0.9	%
Kamigumi	0.8	%

Columbia Acorn International Select ended the fourth quarter up 4.51% (Class A shares, without sales charge) while its primary benchmark, the S&P Developed Ex-U.S. Between $2 Billion and $10 Billion Index, gained 1.14%. For the year ended December 31, 2009, the Fund had a 31.01% return while its benchmark was up 38.60%. Having positioned the Fund well for the previous downturn, the Fund lagged over the past year as the markets were boosted by an unprecedented amount of monetary and fiscal stimulus. Our focus for the Fund has been on companies with competitive market positions and business models, longer-term growth prospects and solid balance sheets, but these companies were not strong performers during 2009 as investor appetite for risk returned and lower quality stocks rallied. We intend to continue to manage the Fund following the approach that has resulted in good outperformance relative to its benchmark and peers over t he past three- and five-year periods.

Naspers was the top dollar contributor to Fund performance for the quarter and for the year. Its stock rose 18% in the fourth quarter and ended the year up 121%. Naspers is a media company with assets in South Africa and other emerging markets that has enjoyed strong earnings growth and has benefited from its stake in the rapidly growing Chinese Internet company, Tencent. Hexagon, a Swedish manufacturer of measurement equipment, gained 23% in the fourth quarter and ended the year up 194%. The company's business fundamentals remained robust throughout the recession due to its strong focus on emerging markets where growth has proven to be more stable.

Canadian potash producer Potash Corp. of Saskatchewan had a 21% gain in the quarter and an annual return of 81% as the market's hope of a bottoming, and subsequently rebounding, potash price fed through to the stock. Ascendas REIT, an industrial property landlord in Singapore, gained 16% in the quarter and ended the year up 75% as the demand for property assets increased with the recovery in Singapore's economy. Canada's Pacific Rubiales Energy, an oil production and exploration company with operating assets in Colombia, gained 19% in the quarter and ended the year up an impressive 680%. The stock has benefited from increasing production and new exploration discoveries in Colombia as well as the rebound in oil prices.

Japanese holdings in the Fund were weak in the fourth quarter as investors flocked to riskier investments and markets. Japan's Seven Bank, Rohto Pharmaceutical, Benesse, Ain Pharmaciez and Kamigumi returned losses ranging from 10% to 20%. Japanese companies were also well represented among the Fund's biggest losers for the annual period, with Jupiter Telecommunications, Nintendo and Seven Bank down between 5% and 30% for the year. We sold out of Nintendo early in the third quarter of 2009. The Japanese economy continues to suffer from a deflationary environment and declining population. While stocks in Japan are beginning to look interesting from a valuation perspective, the growth outlook remains uncertain, and investors reduced their Japanese holdings over the course of the year to focus on companies in other regions. Cephalon, a U.S. pharmaceutical company, was the biggest detractor to the Fund's annual performance, falling m ore than 20% in the Fund. Upcoming patent expirations on several of Cephalon's drugs will make way for competition from generics, and potential health care reform in the United States added to uncertainty about its business. The Fund sold out of its position in Cephalon in the fourth quarter.

International investing may involve certain risks, including currency fluctuations, risks associated with possible differences in financial standards and other monetary and political risks. Significant levels of foreign taxes, including potentially confiscatory levels of taxation and withholding taxes, may also apply to some foreign investments. Stocks of small- and mid-cap companies pose special risks, including possible illiquidity and greater price volatility than stocks of larger, more established companies. Investing in emerging markets may involve greater risks than investing in more developed countries.

Portfolio holdings are subject to change periodically and may not be representative of current holdings.

14

Columbia Acorn International Select (LAFAX)

At a Glance

Performance data quoted represents past performance and current performance may be higher or lower. Past performance is no guarantee of future results. The investment return and principal value of an investment in the Fund will fluctuate so that Fund shares, when redeemed, may be worth more or less than their original cost. Performance results reflect any fee waivers or reimbursements of Fund expenses by the investment advisor and/or any of its affiliates. Absent these fee waivers or expense reimbursement arrangements, performance results would have been lower. Please visit columbiafunds.com for daily and most recent month-end updates.

Pretax and After-tax Average Annual Total Returns (Based on Class A Share Returns)

through December 31, 2009

Inception 10/16/00		1 year	5 years	Life of fund
Returns before taxes	NAV POP	31.01% 23.48	7.62% 6.35	4.25% 3.58
Returns after taxes on distributions	NAV POP	30.66 23.15	7.33 6.07	4.11 3.44
Returns after taxes on distributions and sale of fund shares	NAV POP	20.12 15.23	6.68 5.56	3.75 3.16
S&P Developed Ex-U.S. Between $2 Billion and $10 Billion Index (pretax)*		38.60	4.99	7.18

All results shown assume reinvestment of distributions.

*The Fund's primary benchmark.

After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect the impact of state and local taxes. Returns after taxes on distributions and sale of Fund shares reflect the additional tax impact of long-term gains or losses realized when Fund shares are sold. The returns are taxed at the maximum rate and assume shares were purchased at the beginning of the period. Actual after-tax returns depend on the investor's tax situation and may differ from those shown. After-tax returns are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts. After-tax returns are shown for Class A shares only; after-tax returns for other share classes will vary. Indexes do not reflect any deduction for fees, expenses or taxes. Investment returns and principal value may fluctuate, resulting in a gain or loss on sale.

Public offering price (POP) returns include the maximum sales charge of 5.75% for Class A shares. Net asset value (NAV) returns do not include sales charges or contingent deferred sales charges (CDSC).

The Fund's Class A shares annual operating expense ratio, as stated in the current prospectus, is 1.54%.

Columbia Acorn International Select Portfolio Diversification

as a percentage of net assets, as of 12/31/09

Columbia Acorn International Select Top 10 Holdings

as a percentage of net assets, as of 12/31/09

1.	Naspers (South Africa) Media in Africa & Other Emerging Markets	6.2%
2.	Serco (United Kingdom) Facilities Management	4.9%
3.	Capita Group (United Kingdom) White Collar, Back Office Outsourcing	3.2%
4.	NHN (South Korea) South Korea's Largest Online Search Engine	2.9%
5.	Ascendas REIT (Singapore) Singapore Industrial Property Landlord	2.9%
6.	Olam International (Singapore) Agriculture Supply Chain Manager	2.8%
7.	Red Electrica de Espana (Spain) Spanish Power Transmission	2.6%
8.	Cobham (United Kingdom) Aerospace Components	2.6%
9.	Kansai Paint (Japan) Paint Producer in Japan, India, China & Southeast Asia	2.6%
10.	Intertek Group (United Kingdom) Testing, Inspection & Certification Services	2.6%

The Fund's top 10 holdings and portfolio diversification vary with changes in portfolio investments. See the Statement of Investments for a complete list of the Fund's holdings.

The Growth of a $10,000 Investment in Columbia Acorn International Select (Class A)

October 16, 2000 through December 31, 2009

Illustration is based on a hypothetical $10,000 investment from inception in Class A shares of the Fund, which includes a 5.75% maximum initial sales charge. The S&P Developed Ex-U.S. Between $2 Billion and $10 Billion Index is unmanaged and returns for both the index and the Fund include reinvested dividends and capital gains. Although the index is provided for use in assessing the Fund's performance, the Fund's holdings may differ significantly from those in the index. It is not possible to invest directly in an index. The graph does not reflect taxes that a shareholder would pay on Fund distributions or on a sale of Fund shares.

Total Net Assets of the Fund: $410.7 million

15

Columbia Acorn Select

In a Nutshell

Ben Andrews

Lead Portfolio Manager

Performance data quoted represents past performance and current performance may be lower or higher. Past performance is no guarantee of future results. The investment return and principal value will fluctuate so that shares, when redeemed, may be worth more or less than the original cost. Please visit columbiafunds.com for daily and most recent month-end performance updates.

Fund's Positions
in Mentioned Holdings

As a percentage of net assets,
as of 12/31/09

ITT Educational Services	4.9	%
Pacific Rubiales Energy	4.9	%
Sanmina-SCI	4.7	%
Safeway	3.9	%
Expedia	3.4	%
Canadian Solar	2.8	%
American Commercial Lines	1.1	%
Houston American Energy	0.3	%
GLG Life Tech	0.0	%*
Fu Ji Food & Catering Services	0.0	%*
ChemSpec International	0.0	%*

*Rounds to less than 0.1%.

Columbia Acorn Select gained 7.75% (Class A shares, without sales charge) in the fourth quarter of 2009. This exceeded the 5.56% rise in the Fund's primary benchmark, the S&P MidCap 400 Index. For the year, the Fund outperformed its benchmark by 28 percentage points with a 65.65% gain vs. a 37.38% return for the S&P MidCap 400 Index. We are pleased that we could offer our shareholders such strong performance. The S&P 500 Index, which is a large-cap index, trailed mid-caps with a 26.46% annual return.

The Fund's top two dollar winners for the fourth quarter were Canadian Solar, a solar-power equipment manufacturer, and Sanmina-SCI, a provider of electronic manufacturing services, which together added almost 2.6% to the Fund's performance. The two top dollar losers for the quarter were American Commercial Lines, a barge operator and builder, and ITT Educational Services, a provider of post-secondary degree programs, which together cost the Fund 1.6% of performance. For the year, Pacific Rubiales Energy, an oil production and exploration company, Sanmina-SCI and Expedia, a provider of online travel services, contributed about 20% of the Fund's 66% return. On the downside, pharmaceutical company Cephalon, supermarket chain Safeway and Chinese caterer Fu Ji Food & Catering Services together cost the Fund about 3% of its yearly portfolio return. We sold the Fund's position in Cephalon in the first half of the year.

During the fourth quarter, we added three new companies to the Fund's portfolio. The new investments were GLG Life Tech, ChemSpec International and Houston American Energy. GLG Life Tech produces an all natural, zero calorie sweetener made from the stevia plant. ChemSpec is a fluorinated specialty chemicals manufacturer, and Houston American Energy is an oil and gas exploration and production company with its primary operations in Colombia.

During the quarter we sold the Fund's position in Donaldson, a maker of industrial air filters, FMC Technologies, an oil and gas wellhead manufacturer, and retailer The Gap Stores. We sold down or out of the Fund's larger oil service/production companies while investing the dollars back into smaller oil companies, primarily those located in Colombia.

The U.S. economy is continuing to recover as we enter 2010, but unemployment remains high. However, I believe failure to pass a carbon tax and/or health care legislation could benefit both the economy and the market as it would clear away uncertainty, which is restraining job growth within two of this country's largest employing industries: industrials/oil/utilities and health care. I believe employment could also get a boost if the government chooses not to let the sun setting tax cuts, which are estimated to account for approximately 2% of GDP—a significant figure in an economy with over 10% unemployment—expire at the end of 2010. If these scenarios evolve, employment could rebound. Until then, our focus will be to find stocks that we believe can perform well in a slower growth environment.

Risks include stock market fluctuations due to economic and business developments. The Fund also has potentially greater price volatility due to the Fund's concentration in a limited number of stocks of mid-size companies. The Fund is a non-diversified fund and may, therefore, have a greater risk of loss from a few issuers than a similar fund that invests more broadly. The Fund may not operate as a non-diversified fund at all times. International investments involve greater potential risks, including less regulation, currency fluctuations, economic instability and political developments.

Portfolio holdings are subject to change periodically and may not be representative of current holdings.

16

Columbia Acorn Select (LTFAX)

At a Glance

Performance data quoted represents past performance and current performance may be higher or lower. Past performance is no guarantee of future results. The investment return and principal value of an investment in the Fund will fluctuate so that Fund shares, when redeemed, may be worth more or less than their original cost. Performance results reflect any fee waivers or reimbursements of Fund expenses by the investment advisor and/or any of its affiliates. Absent these fee waivers or expense reimbursement arrangements, performance results would have been lower. Please visit columbiafunds.com for daily and most recent month-end updates.

Pretax and After-tax Average Annual Total Returns (Based on Class A Share Returns)

through December 31, 2009

Inception 10/16/00		1 year	5 years	Life of fund
Returns before taxes	NAV POP	65.65% 56.13	3.87% 2.65	7.52% 6.83
Returns after taxes on distributions	NAV POP	65.65 56.13	3.56 2.34	7.26 6.58
Returns after taxes on distributions and sale of fund shares	NAV POP	42.67 36.48	3.34 2.28	6.62 5.99
S&P MidCap 400 Index (pretax)*		37.38	3.27	5.44

All results shown assume reinvestment of distributions.

*The Fund's primary benchmark.

After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect the impact of state and local taxes. Returns after taxes on distributions and sale of Fund shares reflect the additional tax impact of long-term gains or losses realized when Fund shares are sold. The returns are taxed at the maximum rate and assume shares were purchased at the beginning of the period. Actual after-tax returns depend on the investor's tax situation and may differ from those shown. After-tax returns are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts. After-tax returns are shown for Class A shares only; after-tax returns for other share classes will vary. Indexes do not reflect any deduction for fees, expenses or taxes. Investment returns and principal value may fluctuate, resulting in a gain or loss on sale.

Public offering price (POP) returns include the maximum sales charge of 5.75% for Class A shares. Net asset value (NAV) returns do not include sales charges or contingent deferred sales charges (CDSC).

The Fund's Class A shares annual operating expense ratio, as stated in the current prospectus, is 1.24%.

Columbia Acorn Select Portfolio Diversification

as a percentage of net assets, as of 12/31/09

Columbia Acorn Select Top 10 Holdings

as a percentage of net assets, as of 12/31/09

1.	ITT Educational Services Post-secondary Degree Services	4.9%
2.	Pacific Rubiales Energy (Canada) Oil Production & Exploration in Colombia	4.9%
3.	SkillSoft Web-based Learning Solutions (E-Learning)	4.8%
4.	Sanmina-SCI Electronic Manufacturing Services	4.7%
5.	Hertz Largest U.S. Rental Car Operator	4.6%
6.	Safeway Supermarkets	3.9%
7.	Conseco Life, Long-term Care & Medical Supplement Insurance	3.5%
8.	Expedia Online Travel Services Company	3.4%
9.	Crown Castle International Communications Towers	3.1%
10.	WNS (India) Offshore BPO (Business Process Outsourcing) Services	3.0%

The Fund's top 10 holdings and portfolio diversification vary with changes in portfolio investments. See the Statement of Investments for a complete list of the Fund's holdings.

The Growth of a $10,000 Investment in Columbia Acorn Select (Class A)

October 16, 2000 through December 31, 2009

Illustration is based on a hypothetical $10,000 investment from inception in Class A shares of the Fund, which includes a 5.75% maximum initial sales charge. The S&P MidCap 400 Index is unmanaged and returns for both the index and the Fund include reinvested dividends and capital gains. Although the index is provided for use in assessing the Fund's performance, the Fund's holdings may differ significantly from those in the index. It is not possible to invest directly in an index. The graph does not reflect taxes that a shareholder would pay on Fund distributions or on a sale of Fund shares.

Total Net Assets of the Fund: $1.9 billion

17

Columbia Thermostat Fund

In a Nutshell

Charles P. McQuaid

Lead Portfolio Manager

Performance data quoted represents past performance and current performance may be lower or higher. Past performance is no guarantee of future results. The investment return and principal value will fluctuate so that shares, when redeemed, may be worth more or less than the original cost. Please visit columbiafunds.com for daily and most recent month-end performance updates.

A "fund of funds" bears its allocable share of the costs and expenses of the underlying funds in which it invests. Such funds are thus subject to two levels of fees and potentially higher expense ratios than would be associated with a fund that invests and trades directly in financial instruments under the direction of a single manager.

Columbia Thermostat Fund ended the fourth quarter up 5.62% (Class A shares, without sales charge), outperforming the 0.20% gain of the Barclays Capital U.S. Aggregate Bond Index, the Fund's primary bond benchmark, and underperforming the 6.04% return of the S&P 500 Index, the Fund's primary stock benchmark. For the year, the Fund's 31.98% return topped both indexes. The S&P 500 Index had an annual return of 26.46% and the Barclays Capital U.S. Aggregate Bond Index was up 5.93%.

We recently conducted a review of the structure, allocation percentages and underlying funds that comprise Columbia Thermostat Fund and, as a result of this review, we have made some changes to the Fund's structure. These changes went into effect on January 13, 2010, just after the period covered by this report. The specifics of these investment strategy changes are summarized below:

• We implemented a 90% maximum and a 10% minimum for both stock and bond allocations.

• The allocation of the Fund's assets among underlying stock and bond funds set forth in the Stock/Bond Allocation table in the Fund's prospectus has been modified in two additional ways. First, the increment in the S&P 500 Index that triggers a change in allocation has decreased from 60 to 50 points. Second, the range of the S&P 500 Index has been reduced so that allocations become static when the S&P 500 Index is at 1,000 and under (rather than 960 and under) or over 1,750 (rather than over 2,100).

• Consequently, the Fund now has a smaller percentage of assets in stock funds at the current level of the S&P 500 Index.

• The tighter range and smaller percentage in stock funds reflects our opinion that S&P500 Index earnings and valuations will be lower than we previously expected.

• Believing that many foreign economies are likely to grow faster than the U.S. economy, we increased the stock fund allocation to Columbia Acorn International from 15% to 20%.

• To make room for additional international holdings, we reduced the stock fund allocation to the large-cap blend asset class from 25% to 20%.

• Within the large-cap blend asset class, we added Columbia Contrarian Core Fund as an underlying investment option and will split this allocation with Columbia Large Cap Enhanced Core Fund. Columbia Contrarian Core Fund has a fine track record and currently a greater bias towards growth stocks than Columbia Large Cap Enhanced Core Fund.

Results of the Funds Owned in Columbia Thermostat Fund as of December 31, 2009

Stock Funds Fund	Weightings in category			4th quarter			1 year
Columbia Acorn Fund Z		15	%		5.74	%		39.65	%
Columbia Acorn Select Z		10	%		7.79	%		66.17	%
Columbia Marsico Growth Fund Z		15	%		6.56	%		29.37	%
Columbia Acorn International Z		15	%		4.32	%		50.97	%
Columbia Dividend Income Fund Z		20	%		6.82	%		18.59	%
Columbia Large Cap Enhanced Core Fund Z		25	%		6.11	%		23.99	%
Weighted Average Equity Return/Loss		100	%		6.20	%		33.80	%
Bond Funds Fund	Weightings in category			4th quarter			1 year
Columbia Intermediate Bond Fund Z		50	%		2.08	%		19.11	%
Columbia U.S. Treasury Index Fund Z		30	%		-1.30	%		-3.77	%
Columbia Conservative High Yield Fund Z		20	%		4.21	%		34.96	%
Weighted Average Income Return		100	%		1.49	%		14.74	%

Columbia Thermostat Fund
Rebalancing in the Fourth Quarter

October 15, 2009 85% stocks, 15% bonds

The combination of our change in the allocation table and market movement resulted in Columbia Thermostat Fund having 70% in stock funds and 30% in bond funds as of press time on February 19, 2010.

The value of an investment in the Fund is based primarily on the performance of the underlying portfolio funds and the allocation of the Fund's assets among them. An investment in the underlying portfolio funds may present certain risks, including stock market fluctuations that occur in response to economic and business developments; and a greater degree of social, political and economic volatility associated with international investing. Stocks of small- and mid-cap companies pose special risks, including possible illiquidity and greater price volatility than stocks of larger, more established companies. Value stocks may also be subject to specific business risks that have caused the stocks to be out of favor. Lower-rated and medium quality debt securities are more speculative and incur more risk. International investing may involve certain risks, including currency fluctuations, risks associated with possible differences in financial standards and other monetary and political risks. Significant levels of foreign taxes, including potentially confiscatory levels of taxation and withholding taxes, may also apply to some foreign investments. Changes in interest rates and changes in the financial strength of issuers of lower-rated bonds may also affect underlying fund performance. The Fund is also subject to the risk that the investment advisor's decisions regarding asset classes and underlying portfolio funds will not anticipate market trends successfully, resulting in a failure to preserve capital or lower total return. In addition, the Fund may buy and sell shares of the portfolio funds frequently. This may result in higher transaction costs and additional tax liability. This is not an offer of the shares of any other mutual fund mentioned herein.

18

Columbia Thermostat Fund (CTFAX)

At a Glance

Performance data quoted represents past performance and current performance may be higher or lower. Past performance is no guarantee of future results. The investment return and principal value of an investment in the Fund will fluctuate so that Fund shares, when redeemed, may be worth more or less than their original cost. Performance results reflect any fee waivers or reimbursements of Fund expenses by the investment advisor and/or any of its affiliates. Absent these fee waivers or expense reimbursement arrangements, performance results would have been lower. Please visit columbiafunds.com for daily and most recent month-end updates.

Pretax and After-tax Average Annual Total Returns (Based on Class A Share Returns)

through December 31, 2009

Inception 3/3/03		1 year	5 years	Life of fund
Returns before taxes	NAV POP	31.98% 24.40	2.87% 1.66	6.56% 5.64
Returns after taxes on distributions	NAV POP	31.98 24.39	1.28 0.09	5.20 4.30
Returns after taxes on distributions and sale of fund shares	NAV POP	20.79 15.86	1.83 0.80	5.14 4.33
S&P 500 Index (pretax)*		26.46	0.42	6.30
Barclays Capital U.S. Aggregate Bond Index (pretax)*		5.93	4.97	4.65
Lipper Flexible Portfolio Funds Index (pretax)		29.17	3.50	7.54

All results shown assume reinvestment of distributions.

*The Fund's primary stock and bond benchmarks, respectively.

After-tax returns are calculated using the highest historical individual federal marginal income tax rates, and do not reflect the impact of state and local taxes. Returns after taxes on distributions and sale of Fund shares reflect the additional tax impact of long-term gains or losses realized when Fund shares are sold. The returns are taxed at the maximum rate and assume shares were purchased at the beginning of the period. Actual after-tax returns depend on the investor's tax situation and may differ from those shown. After-tax returns are not relevant to investors who hold their Fund shares through tax-deferred arrangements such as 401(k) plans or individual retirement accounts. After-tax returns are shown for Class A shares only; after-tax returns for other share classes will vary. Indexes do not reflect any deduction for fees, expenses or taxes. Investment returns and principal value may fluctuate, resulting in a gain or loss on sale.

Public offering price (POP) returns include the maximum sales charge of 5.75% for Class A shares. Net asset value (NAV) returns do not include sales charges or contingent deferred sales charges (CDSC).

The Fund's annual operating expense ratio, as stated in the current prospectus, reflects a contractual expense waiver or reimbursement that expires April 30, 2010. Class A expense ratios without and with the contractual waiver, including fees and expenses associated with the Fund's investment in other investment companies, are 1.40% and 1.22%, respectively. Absent the waiver or reimbursement, performance results would have been lower.

Columbia Thermostat Fund Asset Allocation

as a percentage of net assets, as of 12/31/09

Columbia Thermostat Fund Portfolio Weightings

as a percentage of assets in each investment category, as of 12/31/09

Stock Mutual Funds

Columbia Large Cap Enhanced Core Fund, Class Z	25	%
Columbia Dividend Income Fund, Class Z	20	%
Columbia Acorn Fund, Class Z	15	%
Columbia Acorn International, Class Z	15	%
Columbia Marsico Growth Fund, Class Z	15	%
Columbia Acorn Select, Class Z	10	%

Bond Mutual Funds

Columbia Intermediate Bond Fund, Class Z	50	%
Columbia U.S. Treasury Index Fund, Class Z	30	%
Columbia Conservative High Yield Fund, Class Z	20	%

The Growth of a $10,000 Investment in Columbia Thermostat Fund (Class A)

March 3, 2003 through December 31, 2009

Illustration is based on a hypothetical $10,000 investment from inception in Class A shares of the Fund, which includes a 5.75% maximum initial sales charge. The indexes are unmanaged (although the funds that comprise the Lipper Flexible Portfolio Funds Index are managed) and returns for both the indexes and the Fund include reinvested dividends and capital gains. Although the indexes are provided for use in assessing the Fund's performance, the Fund's holdings may differ significantly from those in the index. It is not possible to invest directly in an index. The graph does not reflect taxes that a shareholder would pay on Fund distributions or on a sale of Fund shares.

Total Net Assets of the Fund: $138.6 million

19

Columbia Acorn Fund

Major Portfolio Changes in the Fourth Quarter (Unaudited)

	Number of Shares
	09/30/09		12/31/09
Purchases
Information
AboveNet		500,000		600,000
ANSYS		1,795,000		2,083,291
Art Technology Group		885,000		2,594,654
Blackboard		0		109,007
Blue Coat Systems		786,000		1,534,000
Discovery Communications, Series C		2,636,500		4,070,000
Eutelsat (France)		250,000		400,000
ExlService Holdings		0		747,658
F5 Networks		920,000		1,045,000
Mettler Toledo		1,385,000		1,450,000
Monolithic Power Systems		745,000		870,000
PAETEC Holding		8,500,000		9,600,000
Plexus		1,275,000		1,395,000
Tyler Technologies		632,890		1,134,260
Consumer Goods & Services
Abercrombie & Fitch		2,715,000		4,500,000
Charming Shoppes		5,857,967		7,500,000
Chico's FAS		7,767,000		8,514,272
Diamond Foods		0		550,475
Flowers Foods		497,511		819,000
GLG Life Tech (Canada)		0		1,153,700
Hansen Natural		1,600,000		1,802,600
Hyatt Hotels		0		141,800
Rue21		0		146,390
Smart Balance		2,500,000		3,000,000
Steelcase		2,612,606		3,000,000
Industrial Goods & Services
Airgas		2,275,000		2,555,200
GrafTech International		1,050,000		1,680,000
Jain Irrigation Systems (India)		440,416		1,000,000
Pall		2,000,000		2,150,000
Silgan Holdings		0		200,000
TrueBlue		800,000		924,900
Finance
City National		170,000		295,000
CVB Financial		0		830,700
Eagle Bancorp		0		251,000
Hanover Insurance Group		615,000		849,000
Hudson Valley		0		660,000
Leucadia National		2,220,000		2,427,400
Pacific Continental		0		246,505
SVB Financial Group		960,000		1,172,396
Health Care
Acorda Therapeutics		0		1,300,000
Allos Therapeutics		1,800,000		2,800,000

	Number of Shares
	09/30/09		12/31/09
Allscripts-Misys Healthcare		0		700,000
AthenaHealth		0		250,000
Auxilium Pharmaceuticals		1,250,000		1,350,000
BioMarin		3,000,000		3,250,000
Gen-Probe		0		568,910
Nanosphere		0		1,232,900
PSS World Medical		2,300,000		2,750,000
Seattle Genetics		3,250,000		4,117,700
Sirona Dental Systems		650,500		850,000
Energy & Minerals
Alange Energy (Colombia)		156,500		8,435,000
Baytex (Canada)		0		347,600
Cabot Oil & Gas		0		250,000
Houston American Energy		0		1,200,000
Orko Silver (Canada)		3,500,000		10,000,000
Pan Orient (Canada)		418,500		1,198,100
Cap-Link Ventures		0		24,000,000
Cap-Link Ventures-Warrants		0		24,000,000
PolyMet Mining		1,000,000		1,500,000
Royal Gold		400,000		500,000
STR Holdings		0		400,000
Zhaojin Mining Industry (China)		0		6,333,700
Other Industries
BioMed Realty Trust		1,360,000		2,260,902
Macerich		865,037		880,376
Old Dominion Freight Lines		0		150,000
Terna (Italy)		0		3,500,000

See accompanying notes to financial statements.

20

	Number of Shares
	09/30/09		12/31/09
Sales
Information
American Tower		1,500,000		1,200,000
Cogent Communications		4,300,000		4,200,000
Concur Technologies		1,400,000		1,200,000
Dionex		500,000		400,000
Discovery Communications		1,433,200		0
Dolby Laboratories		1,340,000		1,140,000
FARO Technologies		334,074		0
Intermec		500,000		0
Micros Systems		2,750,544		2,050,544
ON Semiconductor		4,059,000		3,584,000
Quality Systems		902,110		800,000
Radiant Systems		2,204,336		1,000,000
Red Hat		2,000,000		1,000,000
SES (France)		893,000		702,000
Trimble Navigation		1,770,000		1,545,000
Varian		200,000		0
Vasco Data Security International		154,749		0
Consumer Goods & Services
American Apparel		342,382		0
Career Education		1,700,000		1,677,000
Champion Enterprises		4,500,000		0
Choice Hotels		1,700,000		1,300,000
GameStop		1,650,000		0
Herman Miller		3,500,000		2,800,000
HNI		870,000		0
Hot Topic		3,308,890		0
Jarden		2,500,000		1,700,000
Winnebago Industries		650,000		0
Industrial Goods & Services
Aalberts Industries (Netherlands)		2,825,285		2,200,000
Administaff		1,935,000		1,428,224
Clarcor		3,000,000		2,627,500
FreightCar America		225,000		0
Greif		600,000		500,000
Haynes International		390,000		0
Intertek Group (United Kingdom)		299,004		0
Intrepid Potash		275,000		0
Lincoln Electric		350,000		0
Quanta Services		2,300,000		2,070,000
Toro		1,075,000		900,000
Watsco		725,000		625,000
Finance
Assurant		1,530,000		1,200,000
BOK Financial		3,000,000		2,689,000
Eaton Vance		4,235,000		3,735,000
Protective Life		995,000		640,716
West Coast Bancorp		1,000,000		491,788

	Number of Shares
	09/30/09		12/31/09
Health Care
Beckman Coulter		650,000		450,000
Cephalon		1,250,000		475,000
Cepheid		3,200,000		2,500,000
Charles River Laboratories		1,050,000		700,000
Edwards Lifesciences		600,000		500,000
Henry Schein		1,090,000		800,000
Hologic		1,900,000		0
Human Genome Sciences		3,200,000		2,500,000
InterMune		1,300,000		885,000
Kinetic Concepts		900,000		400,000
Luminex		1,700,000		0
Myriad Genetics		1,735,000		1,200,000
Nektar Therapeutics		4,425,000		3,052,000
Poniard		1,450,916		0
Psychiatric Solutions		2,200,000		1,300,000
Thoratec		148,000		0
United Therapeutics		900,000		760,000
Energy & Minerals
Carrizo Oil & Gas		1,167,000		994,900
Trinidad Drilling (Canada)		5,000,000		3,677,900
XTO Energy		1,580,000		0
Other Industries
American Commercial Lines		625,000		602,000
Forest City Enterprises, Class B		1,158,000		1,105,289
SL Green Realty		580,000		440,000

See accompanying notes to financial statements.

21

Columbia Acorn Fund

Statement of Investments, December 31, 2009

Number of Shares			Value (000)
				Equities: 97.2%
Information 25.8%
		> Business Software 4.7%
	7,000,000	Informatica (a)(b)	$	181,020
		Enterprise Data Integration Software
	2,083,291	ANSYS (a)		90,540
		Simulation Software for Engineers & Designers
	2,050,544	Micros Systems (a)		63,628
		Information Systems for Restaurants & Hotels
	12,500,000	Novell (a)		51,875
		Directory, Operating System & Identity Management Software
	1,200,000	Concur Technologies (a)		51,300
		Web Enabled Cost & Expense Management Software
	800,000	Quality Systems		50,231
		IT Systems for Medical Groups & Ambulatory Care Centers
	1,800,000	Blackbaud		42,534
		Software & Services for Non-profits
	2,425,000	Kenexa (a)(b)		31,646
		Recruiting & Workforce Management Solutions
	1,000,000	Red Hat (a)		30,900
		Maintenance & Support for Open Source & Middleware
	1,134,260	Tyler Technologies (a)		22,583
		Financial, Tax, Court & Document Management Systems for Government
	1,000,000	NetSuite (a)(c)		15,980
		End to End IT Systems Solutions Delivered Over the Web
	3,700,000	Actuate (a)(b)		15,836
		Information Delivery Software & Solutions
	2,594,654	Art Technology Group (a)		11,702
		Software & Tools to Optimize Websites for E-commerce
	1,000,000	Radiant Systems (a)		10,400
		IT Systems for Restaurants, Convenience Stores & Retail Stores
	700,000	Avid Technology (a)		8,932
		Digital Nonlinear Editing Software & Systems
	109,007	Blackboard (a)		4,948
		Education Software
				684,055
		> Computer Hardware & Related Equipment 2.9%
	3,800,000	Amphenol		175,484
		Electronic Connectors
	2,400,000	II-VI (a)(b)		76,320
		Laser Optics & Specialty Materials
	1,140,000	Dolby Laboratories (a)		54,412
		Audio Technology for Consumer Electronics
	1,400,000	Zebra Technologies (a)		39,704
		Bar Code Printers
	800,000	Nice Systems - ADR (Israel) (a)		24,832
		Audio & Video Recording Solutions
	970,000	Netgear (a)		21,039
		Networking Products for Small Business & Home
	740,000	Belden CDT		16,221
		Specialty Cable

Number of Shares			Value (000)
	805,000	Stratasys (a)(c)	$	13,911
		Rapid Prototyping Systems
	340,000	Teradata (a)		10,686
		Enterprise Data Warehouse Systems
				432,609
		> Instrumentation 2.9%
	1,450,000	Mettler Toledo (a)		152,235
		Laboratory Equipment
	5,200,000	Hexagon (Sweden)		76,386
		Measurement Equipment
	2,200,000	FLIR Systems (a)		71,984
		Infrared Cameras
	2,750,000	IPG Photonics (a)(b)		46,035
		Fiber Lasers
	1,545,000	Trimble Navigation (a)		38,934
		GPS-based Instruments
	400,000	Dionex (a)		29,548
		Ion & Liquid Chromatography
	400,000	Hamamatsu Photonics (Japan)		9,661
		Optical Sensors for Medical & Industrial Applications
				424,783
		> Mobile Communications 2.6%
	6,575,000	Crown Castle International (a)		256,688
		Communications Towers
	2,000,000	SBA Communications (a)		68,320
		Communications Towers
	1,200,000	American Tower (a)		51,852
		Communications Towers in USA & Latin America
	1,000,000	MetroPCS Communications (a)		7,630
		Discount Cellular Telephone Services
	1,500,000	Globalstar (a)(c)		1,305
		Satellite Mobile Voice & Data Carrier
				385,795
		> Telephone and Data Services 2.0%
	9,500,000	tw telecom (a)(b)		162,830
		Fiber Optic Telephone/Data Services
	4,200,000	Cogent Communications (a)(b)		41,412
		Internet Data Pipelines
	9,600,000	PAETEC Holding (a)(b)		39,840
		Telephone/Data Services for Business
	600,000	AboveNet (a)		39,024
		Metropolitan Fiber Communications Services
	2,000,000	General Communications (a)		12,760
		Commercial Communications & Consumer CATV, Web & Phone in Alaska
				295,866
		> Financial Processors 1.7%
	2,919,000	Global Payments		157,217
		Credit Card Processor
	10,000,000	Singapore Exchange (Singapore)		58,948
		Singapore Equity & Derivatives Market Operator
	2,125,000	Hong Kong Exchanges and Clearing (Hong Kong)		37,830
		Hong Kong Equity & Derivatives Market Operator
				253,995

See accompanying notes to financial statements.

22

Number of Shares			Value (000)
		> CATV 1.4%
	4,070,000	Discovery Communications, Series C (a)	$	107,936
		CATV Programming
	47,000	Jupiter Telecommunications (Japan)		46,564
		Largest Cable Service Provider in Japan
	1,250,000	Liberty Global, Series A (a)		27,388
		Cable TV Franchises Outside the USA
	4,000,000	Mediacom Communications (a)(b)		17,880
		Cable Television Franchises
				199,768
		> Semiconductors & Related Equipment 1.3%
	3,584,000	ON Semiconductor (a)		31,575
		Mixed-signal & Power Management Semiconductors
	1,035,000	Supertex (a)(b)		30,843
		Analog/Mixed-signal Semiconductors
	1,620,000	Microsemi (a)		28,755
		Analog/Mixed-signal Semiconductors
	870,000	Monolithic Power Systems (a)		20,854
		High Performance Analog & Mixed-signal Integrated Circuits (ICs)
	1,765,000	Pericom Semiconductor (a)(b)		20,350
		Interface Integrated Circuits (ICs) & Frequency Control Products
	3,750,000	Entegris (a)		19,800
		Semiconductor Materials Management Products
	500,000	Littelfuse (a)		16,075
		Little Fuses
	1,900,000	IXYS (a)(b)		14,098
		Power Semiconductors
	2,110,000	Integrated Device Technology (a)		13,652
		Communications Semiconductors
				196,002
		> Telecommunications Equipment 1.2%
	1,045,000	F5 Networks (a)		55,364
		Internet Traffic Management Equipment
	1,534,000	Blue Coat Systems (a)		43,780
		WAN Acceleration & Network Security
	1,580,000	Polycom (a)		39,453
		Video Conferencing Equipment
	1,165,000	CommScope (a)		30,908
		Wireless Infrastructure Equipment & Telecom Cable
				169,505
		> Gaming Equipment & Services 1.1%
	4,025,000	Bally Technologies (a)(b)		166,192
		Slot Machines & Software
				166,192
		> Computer Services 1.0%
	5,000,000	iGate (b)		50,000
		IT & Business Process Outsourcing Services
	1,905,000	SRA International (a)		36,386
		Government IT Services
	1,800,000	Virtusa (a)(b)		16,308
		Offshore IT Outsourcing

Number of Shares			Value (000)
	747,658	ExlService Holdings (a)	$	13,577
		Business Process Outsourcing
	4,500,000	Hackett Group (a)(b)		12,510
		IT Integration & Best Practice Research
	736,499	WNS - ADR (India) (a)		11,084
		Offshore BPO (Business Process Outsourcing) Services
	165,000	ManTech International (a)		7,966
		Government IT Services
				147,831
		> Internet Related 0.7%
	2,500,000	Switch & Data Facilities (a)(b)		50,525
		Network Neutral Data Centers
	188,000	NHN (South Korea) (a)		31,044
		South Korea's Largest Online Search Engine
	800,000	Akamai (a)		20,264
		Content Delivery Network (CDN) for Better Delivery of Online Content
	1,000,000	TheStreet.com		2,400
		Financial Information Websites
				104,233
		> Electronics Distribution 0.6%
	3,125,000	Avnet (a)		94,250
		Electronic Components Distribution
				94,250
		> Business Information & Marketing Services 0.5%
	2,500,000	Navigant Consulting (a)(b)		37,150
		Financial Consulting Firm
	650,000	FTI Consulting (a)		30,654
		Financial Consulting Firm
	1,240,000	InfoGROUP (a)		9,945
		Business Data for Sales Leads
				77,749
		> Contract Manufacturing 0.5%
	1,395,000	Plexus (a)		39,757
		Electronic Manufacturing Services
	3,050,000	Sanmina-SCI (a)		33,642
		Electronic Manufacturing Services
				73,399
		> Advertising 0.2%
	2,700,000	VisionChina Media - ADR (China) (a)		29,484
		Advertising on Digital Screens in China's Mass Transit System
				29,484
		> Satellite Broadcasting & Services 0.2%
	702,000	SES (France)		15,741
		Fixed Satellite Services
	400,000	Eutelsat (France)		12,834
		Fixed Satellite Services
				28,575
		> Consumer Software 0.1%
	3,200,000	THQ (a)		16,128
		Entertainment Software
				16,128

See accompanying notes to financial statements.

23

Columbia Acorn Fund

Statement of Investments, continued

Number of Shares			Value (000)
		> Radio 0.1%
	1,541,000	Salem Communications (a)(b)	$	9,230
		Radio Stations for Religious Programming
	164,991	Saga Communications (a)		2,071
		Radio Stations in Small & Mid-sized Cities
	2,400,000	Spanish Broadcasting System (a)(b)		1,872
		Spanish Language Radio Stations
				13,173
		> TV Broadcasting 0.1%
	2,500,000	Entravision Communications (a)		8,500
		Spanish Language TV & Radio Stations
	1,750,000	Gray Television (a)		2,642
		Mid-market Affiliated TV Stations
				11,142
Information: Total				3,804,534
Consumer Goods & Services 18.2%
		> Retail 6.0%
	4,500,000	Abercrombie & Fitch (b)		156,825
		Teen Apparel Retailer
	4,020,000	Urban Outfitters (a)		140,660
		Apparel & Home Specialty Retailer
	4,200,000	lululemon athletica (a)(b)		126,420
		Premium Active Apparel Retailer
	8,514,272	Chico's FAS (a)		119,626
		Women's Specialty Retailer
	2,564,000	J Crew Group (a)		114,713
		Multi-channel Branded Retailer
	7,500,000	Charming Shoppes (a)(b)		48,525
		Women's Specialty Plus Size Apparel Retailer
	3,500,000	AnnTaylor Stores (a)(b)		47,740
		Women's Apparel Retailer
	6,100,000	Saks (a)(c)		40,016
		Luxury Department Store Retailer
	900,000	Gymboree (a)		39,141
		Children's Apparel Specialty Retailer
	4,250,000	Talbots (a)(b)(c)		37,867
		Women's Specialty Retailer
	1,371,366	Gaiam (a)(b)		10,546
		Healthy Living Catalogs & E-Commerce
	146,390	Rue21 (a)		4,112
		Fashion Value Apparel Retailer
				886,191
		> Travel 2.9%
	4,700,000	Expedia (a)		120,837
		Online Travel Services Company
	1,950,000	Vail Resorts (a)(b)		73,710
		Ski Resort Operator & Developer
	3,700,000	Gaylord Entertainment (a)(b)(c)		73,075
		Convention Hotels
	4,700,000	Avis Budget Group (a)		61,664
		Second Largest Car Rental Company
	1,300,000	Choice Hotels		41,158
		Franchisor of Budget Hotel Brands
	3,000,000	Hertz (a)		35,760
		Largest U.S. Rental Car Operator

Number of Shares			Value (000)
	110,000	Pierre & Vacances (France)	$	8,478
		Vacation Apartment Lets
	141,800	Hyatt Hotels (a)		4,227
		Hotel Owner Operator
				418,909
		> Educational Services 2.5%
	1,350,000	ITT Educational Services (a)		129,546
		Post-secondary Degree Services
	9,500,000	SkillSoft - ADR (a)(b)		99,560
		Web-based Learning Solutions (E-Learning)
	550,000	New Oriental Education & Technology - ADR (China) (a)(c)		41,585
		China's Largest Private Education Service Provider
	1,677,000	Career Education (a)		39,091
		Post-secondary Education
	1,750,301	Universal Technical Institute (a)(b)		35,356
		Vocational Training
	3,000,000	Princeton Review (a)(b)		12,180
		College Preparation Courses
	1,268,258	Cambium Learning Group (a)		4,972
		Education Services for the K-12 Market
	2,000,000	Voyager Learning, Contingent Value Rights (d)		336
		Education Services for the K-12 Market
				362,626
		> Apparel 1.7%
	5,930,000	Coach		216,623
		Designer & Retailer of Branded Leather Accessories
	1,500,000	True Religion Apparel (a)(b)		27,735
		Premium Denim
				244,358
		> Nondurables 1.5%
	1,010,000	Chattem (a)(b)		94,233
		Personal Care Products
	1,700,000	Jarden		52,547
		Branded Household Products
	1,700,000	Helen of Troy (a)(b)		41,582
		Hair Dryers & Curling Irons
	550,000	Energizer Holdings (a)		33,704
		Household & Personal Care Products
				222,066
		> Food & Beverage 0.9%
	1,802,600	Hansen Natural (a)		69,220
		Alternative Beverages
	550,475	Diamond Foods		19,564
		Culinary Ingredients & Snack Foods
	819,000	Flowers Foods		19,459
		Bread & Baked Goods
	3,000,000	Smart Balance (a)		18,000
		Healthy Food Products
	1,153,700	GLG Life Tech (Canada) (a)		8,826
		Produce an All-natural Sweetener Extracted from the Stevia Plant
				135,069

See accompanying notes to financial statements.

24

Number of Shares			Value (000)
		> Furniture & Textiles 0.8%
	2,800,000	Herman Miller (b)	$	44,744
		Office Furniture
	4,000,000	Knoll (b)		41,320
		Office Furniture
	3,000,000	Steelcase		19,080
		Office Furniture
	1,000,000	Interface		8,310
		Modular & Broadloom Carpet
				113,454
		> Other Consumer Services 0.5%
	2,150,000	Lifetime Fitness (a)(b)(c)		53,599
		Sport & Fitness Club Operator
	10,976,800	Lifestyle International (Hong Kong)		20,360
		Mid to High-end Department Store Operator in Hong Kong & China
				73,959
		> Casinos & Gaming 0.4%
	4,050,000	Pinnacle Entertainment (a)(b)		36,369
		Regional Casino Operator
	875,000	Penn National Gaming (a)		23,782
		Regional Casino Operator
				60,151
		> Consumer Goods Distribution 0.3%
	2,100,000	Pool		40,068
		Distributor of Swimming Pool Supplies & Equipment
	264,010	Central European Distribution (Poland) (a)		7,501
		Vodka Production & Spirits Distribution
				47,569
		> Leisure Products 0.3%
	1,390,000	Thor Industries		43,646
		RV & Bus Manufacturer
				43,646
		> Restaurants 0.3%
	650,000	P.F. Chang's China Bistro (a)(c)		24,642
		Mandarin Style Restaurants
	2,000,000	AFC Enterprises (a)(b)		16,320
		Popeye's Restaurants
				40,962
		> Other Entertainment 0.1%
	435,000	CTS Eventim (Germany)		21,237
		Event Ticket Sales
				21,237
		> Other Durable Goods —%
	180,000	Cavco Industries (a)		6,466
		Manufactured Homes
				6,466
Consumer Goods & Services: Total				2,676,663
Industrial Goods & Services 18.1%
		> Machinery 7.6%
	4,200,000	Donaldson (b)		178,668
		Industrial Air Filtration

Number of Shares			Value (000)
	4,500,000	Ametek	$	172,080
		Aerospace/Industrial Instruments
	2,700,000	Oshkosh		99,981
		Specialty Truck Manufacturer
	2,627,500	Clarcor (b)		85,236
		Mobile & Industrial Filters
	2,200,000	ESCO Technologies (b)		78,870
		Automatic Electric Meter Readers
	2,150,000	Pall		77,830
		Filtration & Fluids Clarification
	2,300,000	Pentair		74,290
		Pumps & Water Treatment
	1,100,000	Nordson		67,298
		Dispensing Systems for Adhesives & Coatings
	1,975,000	Mine Safety Appliances (b)		52,396
		Safety Equipment
	1,660,000	MOOG (a)		48,522
		Motion Control Products for Aerospace, Defense & Industrial Markets
	1,300,000	Kaydon		46,488
		Specialized Friction & Motion Control Products
	1,225,000	HEICO (b)		44,051
		FAA Approved Aircraft Replacement Parts
	900,000	Toro		37,629
		Turf Maintenance Equipment
	600,000	Wabtec		24,504
		Freight & Transit Component Supplier
	1,000,000	Jain Irrigation Systems (India)		18,790
		Agricultural Micro-irrigation Systems & Food Processing
	114,000	Neopost (France)		9,419
		Postage Meter Machines
				1,116,052
		> Industrial Materials & Specialty Chemicals 2.9%
	2,000,000	Sociedad Quimica y Minera de Chile - ADR (Chile)		75,140
		Producer of Specialty Fertilizers, Lithium & Iodine
	2,200,000	Nalco Holding Company		56,122
		Provider of Water Treatment & Process Chemicals & Services
	1,530,000	Albemarle		55,646
		Refinery Catalysts & Other Specialty Chemicals
	363,000	Novozymes (Denmark)		37,639
		Industrial Enzymes
	1,600,000	Drew Industries (a)(b)		33,040
		RV & Manufactured Home Components
	500,000	Greif		26,990
		Industrial Packaging
	741,176	Carbone Lorraine (France)		26,720
		Advanced Industrial Materials
	15,000	Sika (Switzerland)		23,335
		Chemicals for Construction & Industrial Applications
	1,000,000	Albany International		22,460
		Paper Machine Clothing & Advanced Textiles
	2,000,000	Kansai Paint (Japan)		16,607
		Paint Producer in Japan, India, China & Southeast Asia

See accompanying notes to financial statements.

25

Columbia Acorn Fund

Statement of Investments, continued

Number of Shares			Value (000)
		> Industrial Materials & Specialty Chemicals—continued
	600,000	Crown Holdings (a)	$	15,348
		Metal Can Packaging
	450,000	Celanese		14,445
		Commodity & Specialty Chemicals Provider
	200,000	Silgan Holdings		11,576
		Metal & Plastic Packaging
	350,000	Koppers Holdings		10,654
		Integrated Provider of Carbon Compounds
				425,722
		> Industrial Distribution 2.0%
	2,555,200	Airgas		121,628
		Industrial Gas Distributor
	1,000,000	WW Grainger		96,830
		Industrial Distribution
	2,600,000	Interline Brands (a)(b)		44,902
		Industrial Distribution
	625,000	Watsco		30,612
		HVAC Distribution
				293,972
		> Other Industrial Services 1.8%
	3,300,000	Expeditors International of Washington		114,609
		International Freight Forwarder
	1,500,000	Imtech (Netherlands)		40,253
		Electromechanical & ICT Installation & Maintenance
	1,300,000	Forward Air		32,565
		Freight Transportation Between Airports
	2,000,000	UTI Worldwide		28,640
		Freight Forwarding & Logistics
	1,750,000	Mobile Mini (a)		24,658
		Portable Storage Units Leasing
	924,900	TrueBlue (a)		13,698
		Temporary Manual Labor
	900,000	American Reprographics (a)		6,309
		Document Management & Logistics
				260,732
		> Outsourcing Services 1.2%
	35,000,000	Olam International (Singapore)		65,547
		Agriculture Supply Chain Manager
	2,070,000	Quanta Services (a)		43,139
		Electrical & Telecom Construction Services
	1,428,224	Administaff (b)		33,692
		Professional Employer Organization
	3,000,000	Serco (United Kingdom)		25,505
		Facilities Management
	600,000	GP Strategies (a)		4,518
		Training Programs
				172,401
		> Construction 1.0%
	700,000	Martin Marietta Materials		62,587
		Aggregates
	60,000	NVR (a)		42,642
		D.C. Homebuilder
	850,000	Simpson Manufacturing		22,856
		Wall Joint Maker

Number of Shares			Value (000)
	687,500	Ritchie Brothers Auctioneers (c)	$	15,421
		Heavy Equipment Auctioneer
	384,000	M/I Homes (a)		3,990
		Columbus-based Home Builder
				147,496
		> Waste Management 0.6%
	1,858,500	Republic Services		52,614
		Solid Waste Management
	1,200,000	Waste Connections (a)		40,008
		Solid Waste Management
				92,622
		> Electrical Components 0.4%
	1,300,000	Acuity Brands		46,332
		Commercial Lighting Fixtures
	1,000,000	Ushio (Japan)		16,648
		Industrial Light Sources
				62,980
		> Conglomerates 0.3%
	2,200,000	Aalberts Industries (Netherlands)		31,431
		Flow Control & Heat Treatment
	600,000	Ibiden (Japan)		21,368
		Electronic Parts & Ceramics
				52,799
		> Steel 0.2%
	1,680,000	GrafTech International (a)		26,124
		Industrial Graphite Materials Producer
				26,124
		> Water 0.1%
	1,750,000	Mueller Water Products		9,100
		Fire Hydrants, Valves & Ductile Iron Pipes
				9,100
Industrial Goods & Services: Total				2,660,000
Finance 11.8%
		> Banks 3.7%
	2,689,000	BOK Financial		127,781
		Tulsa-based Southwest Bank
	5,718,205	Valley National Bancorp (c)		80,798
		New Jersey/New York Bank
	4,150,000	TCF Financial		56,523
		Great Lakes Bank
	1,172,396	SVB Financial Group (a)		48,877
		Bank to Venture Capitalists
	2,305,600	MB Financial		45,467
		Chicago Bank
	3,737,900	Associated Banc-Corp (c)		41,154
		Midwest Bank
	640,000	Cullen/Frost Bankers		32,000
		Texas Bank
	2,440,000	Wilmington Trust		30,110
		Delaware Trust Bank
	1,200,000	TriCo Bancshares (b)		19,980
		California Central Valley Bank
	660,000	Hudson Valley		16,276
		Metro New York City Bank

See accompanying notes to financial statements.

26

Number of Shares			Value (000)
		> Banks—continued
	295,000	City National	$	13,452
		Bank & Asset Manager
	830,700	CVB Financial (c)		7,177
		Inland Empire Business Bank
	1,170,000	First Busey		4,551
		Illinois Bank
	500,000	Sandy Spring Bancorp (c)		4,445
		Baltimore, D.C. Bank
	246,505	Pacific Continental		2,820
		Pacific N.W. Bank
	251,000	Eagle Bancorp (a)		2,628
		Metro D.C. Bank
	583,872	Green Bankshares (c)		2,073
		Tennessee Bank
	491,788	West Coast Bancorp		1,033
		Portland Community Bank
				537,145
		> Insurance 2.9%
	2,427,400	Leucadia National (a)		57,748
		Insurance Holding Company
	1,890,000	HCC Insurance Holdings		52,863
		Specialty Insurance
	9,420,000	Conseco (a)		47,100
		Life, Long-term Care & Medical Supplement Insurance
	849,000	Hanover Insurance Group		37,721
		Personal & Commercial Lines Insurance
	1,200,000	Assurant		35,376
		Specialty Insurance
	100,000	Markel (a)		34,000
		Specialty Insurance
	1,450,000	Delphi Financial Group		32,437
		Workers Compensation & Group Employee Benefit Products & Services
	575,000	Navigators Group (a)		27,088
		Specialty Insurance
	1,000,000	Aspen Insurance		25,450
		Commercial Lines Insurance/Reinsurance
	1,420,000	Selective Insurance Group		23,359
		Commercial & Personal Lines Insurance
	832,000	Willis Group (Ireland)		21,948
		Insurance Broker
	900,000	Tower Group		21,069
		Commercial & Personal Lines Insurance
	640,716	Protective Life		10,604
		Life Insurance
				426,763
		> Finance Companies 2.5%
	7,235,000	AmeriCredit (a)(b)		137,754
		Auto Lending
	1,545,000	World Acceptance (a)(b)		55,357
		Personal Loans
	2,350,000	McGrath Rentcorp (b)		52,546
		Temporary Space & IT Rentals
	1,730,000	GATX		49,737
		Rail Car Lessor
	3,300,000	H&E Equipment Services (a)(b)		34,617
		Heavy Equipment Leasing

Number of Shares			Value (000)
	655,000	Aaron's (c)	$	18,163
		Rent to Own
	1,650,000	CAI International (a)(b)		14,900
		International Container Leasing
	1,091,000	Marlin Business Services (a)(b)		8,652
		Small Equipment Leasing
				371,726
		> Brokerage & Money Management 1.6%
	3,735,000	Eaton Vance		113,581
		Specialty Mutual Funds
	6,448,000	SEI Investments		112,969
		Mutual Fund Administration & Investment Management
	700,000	Investment Technology Group (a)		13,790
		Electronic Trading
				240,340
		> Savings & Loans 1.1%
	6,480,000	People's United		108,216
		Connecticut Savings & Loan
	450,000	Housing Development Finance (India)		25,935
		Indian Mortgage Lender
	731,478	ViewPoint Financial		10,541
		Texas Thrift
	1,010,000	Provident New York Bancorp		8,524
		New York State Thrift
	234,693	Berkshire Hills Bancorp		4,854
		Northeast Thrift
				158,070
Finance: Total				1,734,044
Health Care 9.6%
		> Medical Equipment & Devices 3.1%
	3,000,000	Alexion Pharmaceuticals (a)		146,460
		Biotech Focused on Orphan Diseases
	1,700,000	Illumina (a)(c)		52,105
		Leading Tools & Service Provider for Genetic Analysis
	2,400,000	American Medical Systems (a)		46,296
		Medical Devices to Treat Urological Conditions
	500,000	Edwards Lifesciences (a)		43,425
		Heart Valves
	700,000	Haemonetics (a)		38,605
		Blood & Plasma Collection Equipment
	1,000,000	Orthofix International (a)(b)		30,970
		Bone Fixation & Stimulation Devices
	450,000	Beckman Coulter		29,448
		In-vitro Clinical Diagnostics
	850,000	Sirona Dental Systems (a)		26,979
		Manufacturer of Dental Equipment
	568,910	Gen-Probe (a)		24,406
		Molecular In-vitro Diagnostics
	400,000	Kinetic Concepts (a)		15,060
		Wound Healing & Tissue Repair Products

See accompanying notes to financial statements.

27

Columbia Acorn Fund

Statement of Investments, continued

Number of Shares			Value (000)
		> Medical Equipment & Devices—continued
	1,232,900	Nanosphere (a)	$	7,940
		Molecular Diagnostics Company with Best of Breed Platform
				461,694
		> Biotechnology & Drug Delivery 3.0%
	2,500,000	Human Genome Sciences (a)		76,500
		Biotech Focused on HCV, Inflammation & Cancer
	3,250,000	BioMarin (a)		61,132
		Biotech Focused on Orphan Diseases
	4,117,700	Seattle Genetics (a)		41,836
		Antibody-based Therapies for Cancer
	1,350,000	Auxilium Pharmaceuticals (a)		40,473
		Biotech Focused on Niche Disease Areas
	760,000	United Therapeutics (a)		40,014
		Biotech Focused on Rare Diseases
	1,300,000	Acorda Therapeutics (a)		32,786
		Biopharma Company Focused on Nervous Disorder Drugs
	1,200,000	Myriad Genetics (a)		31,320
		Genetic Diagnostics
	3,052,000	Nektar Therapeutics (a)		28,445
		Drug Delivery Technologies
	600,000	AMAG Pharmaceuticals (a)		22,818
		Biotech Focused on Niche Diseases
	2,800,000	Allos Therapeutics (a)(c)		18,396
		Cancer Drug Development
	475,000	Onyx Pharmaceuticals (a)		13,937
		Commercial-stage Biotech Focused on Cancer
	885,000	InterMune (a)		11,540
		Drugs for Pulmonary Fibrosis & Hepatitis C
	1,400,000	Micromet (a)(c)		9,324
		Next-generation Antibody Technology
	2,700,000	NPS Pharmaceuticals (a)(b)		9,180
		Orphan Drugs & Healthy Royalties
	359,944	MicroDose Technologies (a)(d)		162
		Drug Inhaler Development
	187,500	Locus Pharmaceuticals, Series A-1, Pfd. (a)(d)		9
	96,644	Locus Pharmaceuticals, Series B-1, Pfd. (a)(d)		5
		High Throughput Rational Drug Design
				437,877
		> Medical Supplies 1.7%
	800,000	Henry Schein (a)		42,080
		Largest Distributor of Healthcare Products
	1,675,000	QIAGEN (Netherlands) (a)(c)		37,386
		Life Science Tools & Molecular Diagnostics
	665,000	Idexx Laboratories (a)(c)		35,538
		Diagnostic Equipment & Services for Veterinarians
	486,000	Techne		33,320
		Cytokines, Antibodies & Other Reagents for Life Science

Number of Shares			Value (000)
	2,500,000	Cepheid (a)	$	31,200
		Molecular Diagnostics
	850,000	ICU Medical (a)(b)		30,974
		Intravenous Therapy Products
	1,400,000	Immucor (a)		28,336
		Automated Blood Typing Reagents
	150,000	Owens & Minor		6,440
		Distribution of Medical Supplies
				245,274
		> Health Care Services 1.6%
	2,750,000	PSS World Medical (a)		62,067
		Distributor of Medical Supplies
	700,000	Mednax (a)		42,077
		Physician Management for Pediatric & Anesthesia Practices
	1,300,000	Psychiatric Solutions (a)		27,482
		Behavioral Health Services
	4,250,000	eResearch Technology (a)(b)		25,543
		Clinical Research Services
	700,000	Charles River Laboratories (a)		23,583
		Pharmaceutical Research
	850,000	Healthcare Services Group		18,241
		Outsourced Services to Long-term Care Industry
	700,000	Allscripts-Misys Healthcare (a)		14,161
		Clinical IT Solutions for Physician Offices
	800,000	Emdeon (a)		12,200
		Revenue & Payment Cycle Management
	250,000	AthenaHealth (a)		11,310
		Revenue Cycle Management for Physician Offices
				236,664
		> Pharmaceuticals 0.2%
	475,000	Cephalon (a)		29,645
		Specialty Pharmaceuticals for Pain, Central Nervous System & Oncology
	2,450,000	United Drug (Ireland)		7,475
		Irish Pharmaceutical Wholesaler & Outsourcer
				37,120
Health Care: Total				1,418,629
Energy & Minerals 9.3%
		> Oil Services 4.3%
	3,100,000	FMC Technologies (a)		179,304
		Oil & Gas Wellhead Manufacturer
	2,809,568	Fugro (Netherlands)		160,446
		Sub-sea Oilfield Services
	3,200,000	Atwood Oceanics (a)		114,720
		Offshore Drilling Contractor
	1,000,000	Oceaneering International (a)		58,520
		Provider of Sub-sea Services & Manufactured Products
	1,670,000	ShawCor (Canada)		46,866
		Oil & Gas Pipeline Products
	3,677,900	Trinidad Drilling (Canada)		24,863
		Operator of Deep Land Drilling Rigs & Service Rigs Throughout North America

See accompanying notes to financial statements.

28

Number of Shares			Value (000)
		> Oil Services—continued
	1,750,000	Tesco (a)	$	22,592
		Developing New Well Drilling Technologies
	375,000	Bristow (a)		14,419
		Largest Provider of Helicopter Services to Offshore Oil & Gas Producers
	600,000	Tetra Technologies (a)		6,648
		U.S.-based Services Company with Life of Field Approach
	2,983,500	Horizon North Logistics (Canada) (a)		4,707
		Provides Diversified Oil Service Offering in Northern Canada
				633,085
		> Oil & Gas Producers 3.6%
	3,200,000	Southwestern Energy (a)		154,240
		Oil & Gas Producer
	4,910,550	Pacific Rubiales Energy (Canada) (a)		72,542
		Oil Production & Exploration in Colombia
	1,100,000	Range Resources		54,835
		Oil & Gas Producer
	2,400,000	Tullow Oil (United Kingdom)		50,049
		Oil & Gas Producer
	975,000	Ultra Petroleum (a)		48,614
		Oil & Gas Producer
	2,700,000	Denbury Resources (a)		39,960
		Oil Producer Using Co2 Injection
	994,900	Carrizo Oil & Gas (a)		26,355
		Oil & Gas Producer
	4,000,000	Gran Tierra Energy (Canada) (a)		22,948
		Oil Exploration & Production in Colombia, Peru & Argentina
	24,000,000	Cap-Link Ventures (a)(d)		10,097
	24,000,000	Cap-Link Ventures-Warrants (a)(d)		6,425
		Oil & Gas Exploration & Production in Colombia, Peru & Paraguay
	250,000	Cabot Oil & Gas		10,898
		Large Natural Gas Producer in Appalachia & Gulf Coast
	347,600	Baytex (Canada)		9,871
		Oil & Gas Producer in Canada
	1,198,100	Pan Orient (Canada) (a)		8,706
		Growth Oriented & Return Focused Asian Explorer
	1,200,000	Houston American Energy		7,392
		Oil & Gas Exploration/Production in Colombia
	1,500,000	Vaalco Energy		6,825
		Oil & Gas Producer
	8,435,000	Alange Energy (Colombia) (a)		5,081
		Oil & Gas Exploration/Production in Colombia
	264,000	Petrolifera Petroleum (a)		245
		Oil & Gas Exploration & Production in South America
				535,083
		> Mining 1.1%
	2,520,000	Silver Wheaton (Canada) (a)		37,850
		Silver Mining Royalty Company
	290,000	Core Laboratories (Netherlands)		34,255
		Oil & Gas Reservoir Consulting
	500,000	Royal Gold		23,550
		Precious Metals Mining Royalty Company

Number of Shares			Value (000)
	7,725,000	Uranium One (South Africa) (a)	$	22,307
		Uranium Mines in Kazakhstan, the U.S. & Australia
	1,000,000	Ivanhoe Mines (Canada) (a)		14,830
		Copper Mine Project in Mongolia
	6,333,700	Zhaojin Mining Industry (China)		12,493
		Gold Mining & Refining in China
	10,000,000	Orko Silver (Canada) (a)(b)		11,474
		Silver Exploration & Development
	1,500,000	PolyMet Mining (a)(c)		4,590
		Copper & Nickel Miner
				161,349
		> Independent Power 0.1%
	340,000	Wisconsin Energy		16,942
		Wisconsin Utility
				16,942
		> Oil Refining, Marketing & Distribution 0.1%
	175,000	Vopak (Netherlands)		13,826
		World's Largest Operator of Petroleum & Chemical Storage Terminals
				13,826
		> Alternative Energy 0.1%
	400,000	STR Holdings (a)		6,284
		Makes Encapsulant for Solar Power Modules/Provides Quality Assurance
	1,800,000	Synthesis Energy Systems (China) (a)		1,670
		Owner/Operator of Gasification Plants
				7,954
Energy & Minerals: Total				1,368,239
Other Industries 4.4%
		> Real Estate 2.6%
	675,000	Federal Realty Investment Trust		45,711
		Shopping Centers
	850,000	Digital Realty Trust		42,738
		Technology-focused Office Buildings
	2,260,902	BioMed Realty Trust		35,677
		Life Science-focused Office Buildings
	22,000,000	Ascendas REIT (Singapore)		34,453
		Singapore Industrial Property Landlord
	900,000	Corporate Office Properties		32,967
		Office Buildings
	880,376	Macerich (c)		31,649
		Regional Shopping Malls
	900,000	American Campus Communities		25,290
		Student Housing
	40,000,000	Mapletree Logistics Trust (Singapore)		22,290
		Asian Logistics Landlord
	440,000	SL Green Realty		22,106
		Manhattan Office Buildings
	700,000	Washington REIT		19,285
		Washington D.C. Diversified Properties
	3,750,000	DCT Industrial Trust		18,825
		Industrial Properties
	1,400,000	Extra Space Storage		16,170
		Self Storage Facilities

See accompanying notes to financial statements.

29

Columbia Acorn Fund

Statement of Investments, continued

Number of Shares			Value (000)
		> Real Estate—continued
	2,800	Orix JREIT (Japan)	$	13,916
		Diversified REIT
	1,105,289	Forest City Enterprises, Class B (a)		13,131
		Commercial & Residential Property Developer
	2,300,000	Kite Realty Group		9,361
		Community Shopping Centers
	37,407	Security Capital European Realty (Luxembourg) (a)(d)(e)		—
		Self Storage Properties
				383,569
		> Transportation 1.1%
	2,110,000	JB Hunt Transport Services		68,090
		Truck & Intermodal Carrier
	2,480,000	Heartland Express		37,869
		Regional Trucker
	2,500,000	Rush Enterprises, Class A (a)(b)		29,725
	500,000	Rush Enterprises, Class B (a)(b)		5,250
		Truck Sales & Services
	500,000	World Fuel Services		13,395
		Global Fuel Broker
	602,000	American Commercial Lines (a)		11,035
		Operator of Inland Barges/Builder of Barges & Vessels
	150,000	Old Dominion Freight Lines (a)		4,605
		LTL Trucker
				169,969
		> Regulated Utilities 0.7%
	2,200,000	Northeast Utilities		56,738
		Regulated Electric Utility
	500,000	Red Electrica de Espana (Spain)		27,711
		Spanish Power Transmission
	3,500,000	Terna (Italy)		15,060
		Italian Power Transmission
				99,509
Other Industries: Total				653,047
Total Equities: 97.2% (Cost: $10,369,467)				14,315,156
Securities Lending Collateral: 1.3%
	183,433,582	Dreyfus Government Cash Management Fund (f) (7 day yield of 0.000%)		183,434
Total Securities Lending Collateral: (Cost: $183,434)				183,434

Principal Amount (000)			Value (000)
Short-Term Obligations: 3.1%
		> Repurchase Agreement 2.8%
$	413,094	Repurchase Agreement with Fixed Income Clearing Corp., dated 12/31/09, due 1/04/10 at 0.00%, collateralized by U.S. Government Agency obligations with various maturities to 9/17/10, market value $421,361 (repurchase proceeds $413,094)	$	413,094
				413,094
		> Commercial Paper 0.3%
	50,000	Toyota Motor Credit 0.16% due 1/04/10		49,999
				49,999
Total Short-Term Obligations: (Amortized Cost: $463,093)				463,093
Total Investments: 101.6% (Cost: $11,015,994)(g)(h)				14,961,683
Obligation to Return Collateral for Securities Loaned: (1.3)%				(183,434	)
Cash and Other Assets Less Liabilities: (0.3)%				(51,098	)
Total Net Assets: 100.0%			$	14,727,151

ADR = American Depositary Receipts

See accompanying notes to financial statements.

30

> Notes to Statement of Investments (dollar values in thousands)

(a)  Non-income producing security.

(b)  An affiliated person of the Fund may include any company in which the Fund owns five percent or more of its outstanding voting shares. Holdings and transactions in these affiliated companies during the twelve months ended December 31, 2009, are as follows:

Affiliates	Balance of Shares Held 12/31/08		Purchases/ Additions		Sales/ Reductions		Balance of Shares Held 12/31/09		Value		Dividend
Abercrombie & Fitch		1,925,000		2,695,000		120,000		4,500,000	$	156,825	$	2,124
Actuate		1,683,760		2,016,240		-		3,700,000		15,836		-
Administaff		2,025,000		-		596,776		1,428,224		33,692		1,014
AFC Enterprises		1,800,000		200,000		-		2,000,000		16,320		-
AmeriCredit		7,235,000		-		-		7,235,000		137,754		-
AnnTaylor Stores		-		3,500,000		-		3,500,000		47,740		-
Array Biopharma*		2,910,000		-		2,910,000		-		-		-
Avis Budget Group*		-		6,000,000		1,300,000		4,700,000		61,664		-
Bally Technologies		3,750,000		275,000		-		4,025,000		166,192		-
CAI International		1,500,000		150,000		-		1,650,000		14,900		-
Carrizo Oil & Gas*		2,525,000		200,000		1,730,100		994,900		26,355		-
Cepheid*		3,100,000		900,000		1,500,000		2,500,000		31,200		-
Champion Enterprises*		4,500,000		-		4,500,000		-		-		-
Charlotte Russe*		-		1,900,000		1,900,000		-		-		-
Charming Shoppes		-		7,500,000		-		7,500,000		48,525		-
Chattem		1,010,000		-		-		1,010,000		94,233		-
Clarcor		3,000,000		-		372,500		2,627,500		85,236		1,103
Cogent Communications		4,300,000		-		100,000		4,200,000		41,412		-
Conseco*		9,420,000		-		-		9,420,000		47,100		-
Donaldson		4,200,000		-		-		4,200,000		178,668		1,932
Drew Industries		1,324,000		276,000		-		1,600,000		33,040		-
Entravision Communications*		2,500,000		-		-		2,500,000		8,500		-
eResearch Technology		3,935,901		314,099		-		4,250,000		25,543		-
ESCO Technologies		2,200,000		-		-		2,200,000		78,870		-
FARO Technologies*		1,275,000		-		1,275,000		-		-		-
Forest City Enterprises, Class B*		1,158,000		-		52,711		1,105,289		13,131		-
Forward Air*		1,900,000		-		600,000		1,300,000		32,565		413
Gaiam		1,200,000		171,366		-		1,371,366		10,546		-
Gaylord Entertainment		3,300,000		400,000		-		3,700,000		73,075		-
H&E Equipment Services		3,300,000		-		-		3,300,000		34,617		-
Hackett Group		4,600,000		-		100,000		4,500,000		12,510		-
HEICO		850,000		375,000		-		1,225,000		44,051		125
Helen of Troy		1,900,000		-		200,000		1,700,000		41,582		-
Herman Miller		3,000,000		500,000		700,000		2,800,000		44,744		682
Hot Topic*		-		3,791,890		3,791,890		-		-		-
ICU Medical		1,250,000		-		400,000		850,000		30,974		-
iGate		5,000,000		-		-		5,000,000		50,000		550
II-VI		2,400,000		-		-		2,400,000		76,320		-
Informatica		5,500,000		1,500,000		-		7,000,000		181,020		-
Interline Brands		2,000,000		600,000		-		2,600,000		44,902		-
IPG Photonics		2,750,000		-		-		2,750,000		46,035		-
ITT Educational Services*		2,150,000		-		800,000		1,350,000		129,546		-
IXYS		2,035,000		400,000		535,000		1,900,000		14,098		-
Kenexa		2,425,000		-		-		2,425,000		31,646		-
Kite Realty Group*		1,900,000		400,000		-		2,300,000		9,361		1,016
Knoll		3,300,000		700,000		-		4,000,000		41,320		636
Lifetime Fitness		1,900,000		250,000		-		2,150,000		53,599		-
lululemon athletica		-		4,200,000		-		4,200,000		126,420		-
Luminex*		1,110,000		1,343,000		2,453,000		-		-		-
Marlin Business Services		1,091,000		-		-		1,091,000		8,652		-
MB Financial*		2,020,000		285,600		-		2,305,600		45,467		306
McGrath Rentcorp		1,890,000		460,000		-		2,350,000		52,546		1,872
Mediacom Communications		4,000,000		344,085		344,085		4,000,000		17,880		-
Mine Safety Appliances		1,975,000		-		-		1,975,000		52,396		1,896
Mobile Mini*		1,750,000		-		-		1,750,000		24,658		-
Navigant Consulting		2,500,000		-		-		2,500,000		37,150		-
Nektar Therapeutics*		5,325,000		-		2,273,000		3,052,000		28,445		-
NPS Pharmaceuticals		-		2,700,000		-		2,700,000		9,180		-

See accompanying notes to financial statements.

31

Columbia Acorn Fund

Statement of Investments, continued

> Notes to Statement of Investments (dollar values in thousands)

Affiliates	Balance of Shares Held 12/31/08		Purchases/ Additions		Sales/ Reductions		Balance of Shares Held 12/31/09		Value		Dividend
Orko Silver		-		10,000,000		-		10,000,000	$	11,474	$	-
Orthofix International		600,000		400,000		-		1,000,000		30,970		-
PAETEC Holding		8,000,000		1,600,000		-		9,600,000		39,840		-
Pericom Semiconductor		915,000		850,000		-		1,765,000		20,350		-
Pinnacle Entertainment		4,050,000		-		-		4,050,000		36,369		-
Pool*		2,600,000		-		500,000		2,100,000		40,068		1,287
Princeton Review		2,550,000		450,000		-		3,000,000		12,180		-
Quality Systems*		1,850,000		-		1,050,000		800,000		50,232		1,665
Radiant Systems*		3,050,000		-		2,050,000		1,000,000		10,400		-
Rush Enterprises		2,750,000		250,000		-		3,000,000		34,975		-
Salem Communications		1,541,000		-		-		1,541,000		9,230		-
Savient Pharmaceuticals*		1,416,941		1,583,059		3,000,000		-		-		-
SeaBright Insurance Holdings*		1,200,000		-		1,200,000		-		-		-
Seattle Genetics*		4,400,000		867,700		1,150,000		4,117,700		41,836		-
SkillSoft - ADR		9,500,000		-		-		9,500,000		99,560		-
Smart Balance*		5,000,000		500,000		2,500,000		3,000,000		18,000		-
Spanish Broadcasting System		2,400,000		-		-		2,400,000		1,872		-
Stewart Information Services*		909,420		-		909,420		-		-		-
Stratasys*		1,180,000		-		375,000		805,000		13,911		-
Supertex		1,035,000		-		-		1,035,000		30,843		-
Switch & Data Facilities		2,500,000		-		-		2,500,000		50,525		-
Talbots		4,250,000		-		-		4,250,000		37,867		-
TriCo Bancshares		1,200,000		-		-		1,200,000		19,980		624
True Religion Apparel		1,150,000		633,000		283,000		1,500,000		27,735		-
tw telecom		9,500,000		-		-		9,500,000		162,830		-
Universal Technical Institute		1,500,000		250,301		-		1,750,301		35,356		-
Vail Resorts		2,390,000		-		440,000		1,950,000		73,710		-
Viad*		1,032,075		-		1,032,075		-		-		73
Virtusa		1,000,000		800,000		-		1,800,000		16,308		-
Voyager Learning*		2,000,000		-		2,000,000		-		-		-
West Coast Bancorp*		837,000		163,000		508,212		491,788		1,033		28
World Acceptance		1,545,000		-		-		1,545,000		55,357		-
Total of Affiliated Transactions		225,449,097		62,694,340		45,551,769		242,591,668	$	3,750,852	$	17,346

*  At December 31, 2009, the Fund owned less than five percent of the company's outstanding voting shares.

  The aggregate cost and value of these companies at December 31, 2009, were $3,167,879 and $3,750,852, respectively. Investments in affiliated companies represented 25.5% of the Fund's total net assets at December 31, 2009.

(c)  All or a portion of this security was on loan at December 31, 2009. The total market value of Fund securities on loan at December 31, 2009 was $175,896.

(d)  Denotes a restricted security, which is subject to restrictions on resale under federal securities laws. These securities are valued at a fair value determined in good faith under consistently applied procedures established by the Board of Trustees. At December 31, 2009, the market value of these securities amounted to $17,034, which represented 0.12% of total net assets.

  Additional information on these securities is as follows:

Security	Acquisition Dates	Shares		Cost		Value
Cap-Link Ventures	11/20/09		24,000,000	$	4,898	$	10,097
Cap-Link Ventures-Warrants	11/20/09		24,000,000		3,117		6,425
Voyager Learning, Contingent Value Rights	12/24/09		2,000,000		-		336
MicroDose Technologies	11/24/00		359,944		2,005		162
Locus Pharmaceuticals, Series A-1, Pfd.	9/05/01		187,500		7,500		9
Locus Pharmaceuticals, Series B-1, Pfd.	2/08/07		96,644		280		5
Security Capital European Realty	8/20/98-7/20/99		37,407		205		-
				$	18,005	$	17,034

(e)  Security has no value.

(f)  Investment made with cash collateral received from securities lending activity.

(g)  At December 31, 2009, for federal income tax purposes, the cost of investments was $11,076,313 and net unrealized appreciation was $3,885,370, consisting of gross unrealized appreciation of $5,220,362 and gross unrealized depreciation of $1,334,992.

See accompanying notes to financial statements.

32

> Notes to Statement of Investments (dollar values in thousands)

(h)  On December 31, 2009, the market value of foreign securities represented 11.08% of total net assets. The Fund's foreign portfolio was diversified as follows:

	Value		Percentage of Net Assets
Netherlands	$	317,597		2.16
Canada		263,483		1.79
Singapore		181,238		1.23
Japan		124,764		0.85
China		85,232		0.58
Sweden		76,386		0.52
United Kingdom		75,554		0.51
Chile		75,140		0.51
France		73,192		0.5
Hong Kong		58,190		0.39
India		55,809		0.38
	Value		Percentage of Net Assets
South Korea	$	53,351		0.36
Denmark		37,639		0.26
Ireland		29,423		0.20
Spain		27,711		0.19
Israel		24,832		0.17
Switzerland		23,335		0.16
Germany		21,237		0.14
Italy		15,060		0.1
Poland		7,501		0.05
Colombia		5,081		0.03
Luxembourg		-		-
Total Foreign Portfolio	$	1,631,755		11.08

The following table summarizes the inputs used, as of December 31, 2009, in valuing the Fund's assets:

Investment Type	Quoted Prices (Level 1)		Other Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Equities
Information	$	3,515,526	$	289,008	$	-	$	3,804,534
Consumer Goods & Services		2,626,252		50,075		336		2,676,663
Industrial Goods & Services		2,326,738		333,262		-		2,660,000
Finance		1,708,109		25,935		-		1,734,044
Health Care		1,410,978		7,475		176		1,418,629
Energy & Minerals		1,114,903		253,336		-		1,368,239
Other Industries		539,617		113,430		-		653,047
Total Equities		13,242,123		1,072,521		512		14,315,156
Total Securities Lending Collateral		183,434		-		-		183,434
Total Short-Term Obligations		-		463,093		-		463,093
Total Investments	$	13,425,557	$	1,535,614	$	512	$	14,961,683

  The Fund's assets assigned to the Level 2 input category include certain foreign securities for which a third party statistical pricing service may be employed for purposes of fair market valuation.

  The following table reconciles asset balances for the twelve-month period ending December 31, 2009, in which significant unobservable inputs (Level 3) were used in determining value:

Investments in Securities	Balance as of December 31, 2008		Accrued Discounts/ Premiums		Realized Gain/(Loss)			Change in Unrealized Appreciation (Depreciation)		Net Purchases (Sales)		Net Transfers into (out of) Level 3		Balance as of December 31, 2009
Equities
Consumer Goods & Services	$	-	$	-	$	-		$	-	$	-	$	336	$	336
Health Care		426		-		(4,500	)		4,250		-		-		176
	$	426	$	-	$	(4,500	)	$	4,250	$	-	$	336	$	512

  The information in the above reconciliation table represents fiscal year to date activity for any securities identified as using Level 3 inputs during the current fiscal period.

  The change in unrealized appreciation (depreciation) attributed to securities owned at December 31, 2009, which were valued using significant unobservable inputs (Level 3) amounted to $4,250. This amount is included in net change in unrealized appreciation on the Statements of Changes in Net Assets.

  For more information on valuation inputs, and their aggregation into the levels used in the tables above, please refer to the Security Valuation section in the accompanying Notes to Financial Statements.

See accompanying notes to financial statements.

33

Columbia Acorn International

Major Portfolio Changes in the Fourth Quarter (Unaudited)

	Number of Shares
	09/30/09		12/31/09
Purchases
Asia
> Japan
Icom		213,700		312,000
Makita		430,000		590,000
Torishima Pump Manufacturing		339,100		633,800
> China
China Communication Services		0		24,952,000
Shandong Weigao		5,018,500		6,000,000
Sino Ocean Land		0		15,782,000
Zhaojin Mining Industry		0		11,764,400
> India
Jain Irrigation Systems		1,868,376		2,000,000
Patel Engineering		878,824		1,271,000
> Taiwan
Everlight Electronics		8,704,793		9,297,575
Simplo Technology		4,020,500		5,693,500
Yuanta Financial Holdings		45,000,000		55,734,000
Europe
> United Kingdom
Chemring		400,000		580,000
Cobham		4,950,000		6,800,000
N Brown Group		3,150,000		3,465,000
Schroders		1,350,000		1,466,000
Serco		6,100,000		6,500,000
Spice Group		0		4,722,884
> Netherlands
Smit Internationale		244,969		339,146
Vopak		474,600		520,100
> France
Eutelsat		437,000		583,000
Hi-Media		730,000		966,229
Saft		469,574		506,362
Zodiac Aerospace		411,000		541,000
> Germany
Elringklinger		696,311		750,000
Tognum		790,000		960,000
Vossloh		200,000		245,000
Wirecard		0		1,180,000
> Switzerland
Bank Sarasin & Cie		126,406		349,882
> Sweden
East Capital Explorer		750,000		982,742
Sweco		3,235,000		3,887,000
> Italy
Ansaldo STS		0		1,029,000
CIR		9,610,356		11,180,000

	Number of Shares
	09/30/09		12/31/09
Credito Emiliano		2,639,000		3,069,000
Terna		0		5,246,000
> Ireland
Paddy Power		300,300		448,000
> Spain
Red Electrica de Espana		532,000		573,000
> Greece
Intralot		3,427,000		3,725,000
> Portugal
Redes Energéticas Nacionais		0		3,909,580
> Iceland
Marel		22,568,604		29,868,604
Other Countries
> Canada
Baytex		0		432,900
Pan Orient		517,100		1,480,610
> United States
Bristow		300,000		391,000
> Australia
Australian Stock Exchange		550,000		700,000
SAI Global		0		460,092
Seek		0		731,000
United Group		965,000		2,068,000

See accompanying notes to financial statements.

34

	Number of Shares
	09/30/09		12/31/09
Sales
Asia
> Japan
Aeon Mall		1,146,300		955,500
Asics		2,143,500		1,905,500
Benesse		398,900		306,900
Point		519,570		478,570
Unicharm PetCare		390,300		336,300
> China
China Shipping Development		7,891,000		0
RexLot Holdings		250,000,000		240,000,000
> Singapore
Mapletree Logistics Trust		77,000,000		70,000,000
> Taiwan
President Chain Store		11,353,184		0
> Hong Kong
Hong Kong Exchanges and Clearing		2,700,000		2,500,000
NagaCorp		73,217,756		29,595,256
Europe
> United Kingdom
Intermediate Capital		864,000		0
Randgold Resources - ADR		212,000		0
> Netherlands
Aalberts Industries		2,005,935		1,750,935
> France
Iliad		246,000		0
SES		944,000		759,000
> Germany
Wincor Nixdorf		524,000		335,000
> Sweden
Hexagon		3,944,000		3,756,000
Nobia		4,572,226		3,362,226
> Ireland
Aryzta		600,000		330,000
Other Countries
> United States
Illumina		300,000		0
Latin America
> Mexico
Urbi Desarrollos Urbanos		18,000,000		15,000,000

See accompanying notes to financial statements.

35

Columbia Acorn International

Statement of Investments, December 31, 2009

Number of Shares			Value (000)
				Equities: 95.6%
Asia 38.7%
		> Japan 15.3%
	6,550,000	Kansai Paint	$	54,386
		Paint Producer in Japan, India, China & Southeast Asia
	31,500	Jupiter Telecommunications		31,208
		Largest Cable Service Provider in Japan
	12,500	Nippon Residential Investment (a)		30,372
		Residential REIT
	478,570	Point		26,719
		Apparel Specialty Retailer
	4,800	Orix JREIT		23,856
		Diversified REIT
	3,283,000	Kamigumi		23,855
		Port Cargo Handling & Logistics
	2,027,000	Rohto Pharmaceutical		23,331
		Health & Beauty Products
	640,000	Ibiden		22,793
		Electronic Parts & Ceramics
	1,016,000	Glory		22,468
		Currency Handling Systems & Related Equipment
	1,544,000	Aeon Delight		21,854
		Facility Maintenance & Management
	11,000	Seven Bank		21,847
		ATM Processing Services
	4,300	Osaka Securities Exchange		20,389
		Osaka Securities Exchange
	3,860	Nippon Accommodations Fund		20,121
		Residential REIT
	590,000	Makita		20,075
		Power Tools
	737,000	Kintetsu World Express		19,112
		Airfreight Logistics
	955,500	Aeon Mall		18,490
		Suburban Shopping Mall Developer, Owner & Operator
	1,905,500	Asics		17,060
		Footwear & Apparel
	7,500	Wacom		16,235
		Computer Graphic Illustration Devices
	3,050	Fukuoka		15,912
		Diversified REIT in Fukuoka
	787,200	Daiseki		15,850
		Waste Disposal & Recycling
	950,000	Ushio		15,815
		Industrial Light Sources
	643,000	Ain Pharmaciez		15,427
		Dispensing Pharmacy/Drugstore Operator
	480,000	Olympus		15,423
		Medical Equipment (Endoscopes) & Cameras
	193,000	Nakanishi		15,336
		Dental Tools & Machinery
	1,750,000	Suruga Bank		15,180
		Regional Bank
	587,800	Miura		14,838
		Industrial Boiler

Number of Shares			Value (000)
	580,000	Hamamatsu Photonics	$	14,008
		Optical Sensors for Medical & Industrial Applications
	633,800	Torishima Pump Manufacturing		13,701
		Industrial Pump for Power Generation & Water Supply Systems
	306,900	Benesse		12,834
		Education Service Provider
	345,000	Tsumura		11,112
		Traditional Chinese/Japanese Herbal Rx Drugs (Kampo)
	3,100,000	Chuo Mitsui Trust Holdings		10,346
		Trust Bank
	336,300	Unicharm PetCare		10,285
		Pet Food & Pet Toiletries
	2,470	Kakaku.com		9,590
		Online Price Comparison Services for Consumers
	822,000	Zenrin		9,478
		Map Content Publisher
	785,000	Tamron		7,928
		Camera Lens Maker
	312,000	Icom		6,690
		Two Way Radio Communication Equipment
	116,300	Toyo Tanso		5,604
		Carbon & Graphite Products for Industrial Use
	2,349	Start Today		4,278
		Online Apparel Mall
	208,900	As One		3,642
		Scientific Supplies Distributor
				677,448
		> China 5.8%
	10,107,000	China Yurun Food		29,827
		Meat Processor in China
	382,000	New Oriental Education & Technology - ADR (b)(c)		28,883
		China's Largest Private Education Service Provider
	31,987,000	Jiangsu Expressway		28,457
		Chinese Toll Road Operator
	29,166,400	China Green		27,607
		Chinese Fruit & Vegetable Grower & Processor
	240,000,000	RexLot Holdings		26,792
		Lottery Equipment Supplier in China
	703,800	Mindray - ADR (c)		23,873
		Medical Device Manufacturer
	11,764,400	Zhaojin Mining Industry		23,204
		Gold Mining & Refining in China
	6,000,000	Shandong Weigao		19,927
		Vertically Integrated Hospital Consumable Manufacturer
	15,782,000	Sino Ocean Land		14,455
		Property Developer in China
	12,316,000	Wasion Group		12,744
		Electronic Power Meter Total Solution Provider
	24,952,000	China Communication Services		12,203
		China's Telecom Infrastructure Service Provider
	1,000,000	VisionChina Media - ADR (b)		10,920
		Advertising on Digital Screens in China's Mass Transit System

See accompanying notes to financial statements.

36

Number of Shares			Value (000)
		> China—continued
	15,300,000	Fu Ji Food & Catering Services (b)(d)	$	158
		Food Catering Service Provider in China
				259,050
		> Singapore 4.9%
	35,000,000	Olam International		65,547
		Agriculture Supply Chain Manager
	7,000,000	Singapore Exchange		41,263
		Singapore Equity & Derivatives Market Operator
	70,000,000	Mapletree Logistics Trust		39,008
		Asian Logistics Landlord
	30,000,000	CDL Hospitality Trust		36,903
		Hotel Owner/Operator
	21,000,000	Ascendas REIT		32,887
		Singapore Industrial Property Landlord
				215,608
		> India 3.8%
	1,008,727	Asian Paints		38,681
		India's Largest Paint Company
	2,000,000	Jain Irrigation Systems		37,580
		Agricultural Micro-irrigation Systems & Food Processing
	450,000	Housing Development Finance		25,935
		Indian Mortgage Lender
	2,135,000	Shriram Transport Finance		22,132
		Truck Financing in India
	1,570,000	Mundra Port & Special Economic Zone		18,568
		Indian West Coast Shipping Port
	900,000	Educomp Solutions		13,690
		Multimedia Educational Content
	1,271,000	Patel Engineering		12,207
		Civil Engineering & Construction
				168,793
		> South Korea 3.3%
	245,000	NHN (b)		40,456
		South Korea's Largest Online Search Engine
	182,000	MegaStudy		37,291
		Online Education Service Provider
	909,000	Woongjin Coway		29,970
		South Korean Household Appliance Rental Service Provider
	376,000	Mirae Asset Securities		20,891
		South Korean Largest Diversified Financial Company
	298,000	Taewoong		19,069
		Niche Custom Forging
				147,677
		> Taiwan 2.9%
	55,734,000	Yuanta Financial Holdings		40,621
		Financial Holding Company in Taiwan
	9,297,575	Everlight Electronics		34,672
		LED Packager
	5,693,500	Simplo Technology		33,564
		World's Largest Notebook Battery Pack Supplier
	1,454,200	Formosa International Hotels		18,636
		Hotel, Food & Beverage Operation & Hospitality Management Services
				127,493

Number of Shares			Value (000)
		> Hong Kong 2.0%
	2,500,000	Hong Kong Exchanges and Clearing	$	44,506
		Hong Kong Equity & Derivatives Market Operator
	22,154,200	Lifestyle International		41,092
		Mid to High-end Department Store Operator in Hong Kong & China
	29,595,256	NagaCorp		3,269
		Casino/Entertainment Complex in Cambodia
				88,867
		> Indonesia 0.7%
	75,000,000	Perusahaan Gas Negara		30,975
		Gas Distributor & Pipeline Operator
				30,975
Asia: Total				1,715,911
Europe 36.9%
		> United Kingdom 6.9%
	6,500,000	Serco		55,261
		Facilities Management
	3,300,000	Capita Group		39,804
		White Collar, Back Office Outsourcing
	1,890,000	Intertek Group		38,055
		Testing, Inspection & Certification Services
	1,466,000	Schroders		31,293
		United Kingdom Top Tier Asset Manager
	6,800,000	Cobham		27,410
		Aerospace Components
	580,000	Chemring		27,293
		Defense Manufacturer of Countermeasures & Energetics
	4,600,000	RPS Group		15,996
		Environmental Consulting & Planning
	690,000	Tullow Oil		14,389
		Oil & Gas Producer
	3,465,000	N Brown Group		13,770
		Home Shopping Women's Clothes Retailer
	682,000	Rotork		13,053
		Valve Actuators for Oil & Water Pipelines
	1,250,000	Smith & Nephew		12,835
		Medical Equipment & Supplies
	1,110,000	Keller Group		11,477
		Ground Engineering
	4,722,884	Spice Group		4,611
		United Kingdom Utility Outsourcing
				305,247
		> Netherlands 6.8%
	1,871,250	Imtech		50,216
		Electromechanical & ICT Installation & Maintenance
	735,945	Fugro		42,028
		Sub-sea Oilfield Services
	520,100	Vopak		41,091
		World's Largest Operator of Petroleum & Chemical Storage Terminals
	1,372,989	Koninklijke TenCate (a)		36,081
		Advanced Textiles & Industrial Fabrics

See accompanying notes to financial statements.

37

Columbia Acorn International

Statement of Investments, continued

Number of Shares			Value (000)
		> Netherlands—continued
	1,385,000	Unit 4 Agresso (a)(b)	$	32,644
		Business Software Development
	339,146	Smit Internationale		29,195
		Harbor & Offshore Towage & Marine Services
	1,750,935	Aalberts Industries		25,015
		Flow Control & Heat Treatment
	1,088,187	Arcadis		24,480
		Engineering Consultants
	650,000	QIAGEN (b)		14,520
		Life Science Tools & Molecular Diagnostics
	62,000	Core Laboratories		7,323
		Oil & Gas Reservoir Consulting
				302,593
		> France 4.4%
	328,000	Neopost		27,100
		Postage Meter Machines
	506,362	Saft		24,392
		Niche Battery Manufacturer
	541,000	Zodiac Aerospace		22,577
		Leading Supplier to the Aerospace Industry
	271,000	Pierre & Vacances		20,888
		Vacation Apartment Lets
	531,176	Carbone Lorraine		19,149
		Advanced Industrial Materials
	583,000	Eutelsat		18,705
		Fixed Satellite Services
	759,000	SES		17,019
		Fixed Satellite Services
	170,000	Rubis		14,911
		Tank Storage & Liquefied Petroleum Gas Distribution
	259,664	Eurofins Scientific		14,126
		Food, Pharmaceuticals & Materials Screening & Testing
	160,701	Norbert Dentressangle		8,780
		Leading European Logistics & Transport Group
	966,229	Hi-Media (b)		6,768
		Online Advertiser in Europe
				194,415
		> Germany 4.3%
	700,000	CTS Eventim		34,175
		Event Ticket Sales
	245,000	Vossloh		24,408
		Rail Infrastructure & Diesel Locomotives
	335,000	Wincor Nixdorf		22,851
		Retail POS Systems & ATM Machines
	127,000	Rational		21,514
		Commercial Oven Manufacturer
	850,000	Rhoen-Klinikum		20,790
		Health Care Services
	750,000	Elringklinger		17,515
		Automobile Components
	1,180,000	Wirecard		16,223
		Online Payment Processing & Risk Management
	960,000	Tognum		15,927
		Diesel Engines for Drive & Power Generation Systems

Number of Shares			Value (000)
	354,500	Deutsche Beteiligungs	$	8,686
		Private Equity Investment Management
	700,000	Takkt		7,181
		Mail Order Retailer of Office & Warehouse Durables
				189,270
		> Switzerland 2.7%
	185,000	Geberit		32,770
		Plumbing Supplies
	20,500	Sika		31,891
		Chemicals for Construction & Industrial Applications
	275,000	Kuehne & Nagel		26,602
		Freight Forwarding/Logistics
	85,000	Burckhardt Compression		15,212
		Manufactures & Services Compressors
	349,882	Bank Sarasin & Cie (b)		13,223
		Private Banking
				119,698
		> Sweden 2.6%
	3,756,000	Hexagon		55,174
		Measurement Equipment
	3,887,000	Sweco		29,084
		Engineering Consultants
	3,362,226	Nobia (b)		19,704
		Kitchen Cabinet Manufacturing & Sales
	982,742	East Capital Explorer (b)		9,180
		Sweden-based RUS/CEE Investment Fund
				113,142
		> Italy 2.1%
	11,180,000	CIR (b)		28,868
		Italian Holding Company
	3,069,000	Credito Emiliano (b)		23,556
		Italian Regional Bank
	5,246,000	Terna		22,572
		Italian Power Transmission
	1,029,000	Ansaldo STS		19,525
		Leading Systems Integrator for the Railway Industry
				94,521
		> Finland 2.0%
	1,382,777	Stockmann		37,680
		Department Store & Fashion Retailer in Scandinavia & Russia
	1,756,000	Poyry		28,127
		Engineering Consultants
	2,170,000	Ramirent (b)		21,155
		Largest Equipment Rental Company in Scandinavia & Central Eastern Europe
				86,962
		> Ireland 1.2%
	8,100,000	United Drug		24,715
		Irish Pharmaceutical Wholesaler & Outsourcer
	448,000	Paddy Power		15,877
		Irish Betting Services
	330,000	Aryzta		12,091
		Baked Goods
				52,683

See accompanying notes to financial statements.

38

Number of Shares			Value (000)
		> Spain 0.9%
	573,000	Red Electrica de Espana	$	31,757
		Spanish Power Transmission
	1,546,000	ENCE (b)		5,968
		Europe's Leading Eucalyptus Pulp Maker
				37,725
		> Denmark 0.7%
	306,000	Novozymes		31,729
		Industrial Enzymes
				31,729
		> Poland 0.6%
	975,900	Central European Distribution (b)		27,725
		Vodka Production & Spirits Distribution
				27,725
		> Czech Republic 0.5%
	114,000	Komercni Banka		24,302
		Leading Czech Universal Bank
				24,302
		> Greece 0.5%
	3,725,000	Intralot		21,654
		Lottery & Gaming Systems & Services
				21,654
		> Portugal 0.4%
	3,909,580	Redes Energéticas Nacionais		16,794
		Portuguese Power Transmission & Gas Transportation
				16,794
		> Iceland 0.3%
	29,868,604	Marel (b)		14,881
		Largest Manufacturer of Poultry & Fish Processing Equipment
				14,881
Europe: Total				1,633,341
Other Countries 14.4%
		> Canada 4.2%
	3,927,000	Eldorado Gold (b)		56,022
		Gold Miner in Turkey, Greece, China & Brazil
	1,710,000	ShawCor		47,988
		Oil & Gas Pipeline Products
	1,117,000	CCL Industries		30,172
		Leading Global Label Manufacturer
	850,000	Ivanhoe Mines (b)		12,606
	744,000	Ivanhoe Mines (b)(e)		10,870
		Copper Mine Project in Mongolia
	432,900	Baytex		12,293
		Oil & Gas Producer in Canada
	1,480,610	Pan Orient (b)		10,759
		Growth Oriented & Return Focused Asian Explorer
	2,262,100	Horizon North Logistics (b)		3,569
		Provides Diversified Oil Service Offering in Northern Canada
				184,279

Number of Shares			Value (000)
		> United States 3.9%
	1,340,000	Atwood Oceanics (b)	$	48,039
		Offshore Drilling Contractor
	625,000	Alexion Pharmaceuticals (b)		30,513
		Biotech Focused on Orphan Diseases
	346,000	Oceaneering International (b)		20,248
		Provider of Sub-sea Services & Manufactured Products
	660,000	World Fuel Services		17,681
		Global Fuel Broker
	391,000	Bristow (b)		15,034
		Largest Provider of Helicopter Services to Offshore Oil & Gas Producers
	251,000	FMC Technologies (b)		14,518
		Oil & Gas Wellhead Manufacturer
	725,000	BioMarin (b)		13,637
		Biotech Focused on Orphan Diseases
	430,000	Ritchie Brothers Auctioneers (c)		9,645
		Heavy Equipment Auctioneer
	324,000	Tesco (b)		4,183
		Developing New Well Drilling Technologies
				173,498
		> Australia 2.6%
	2,068,000	United Group		26,333
		Engineering & Facilities Management
	700,000	Perpetual Trustees		23,103
		Mutual Fund Management
	700,000	Australian Stock Exchange		21,801
		Australian Equity & Derivatives Market Operator
	2,000,000	Billabong International		19,444
		Action Sports Apparel Brand Manager
	262,000	Cochlear		16,178
		Cochlear Implants for Hearing
	731,000	Seek		4,492
		Online Job Listing & Education
	460,092	SAI Global		1,655
		Publishing, Certification & Compliance Services
	555,740	Hastie Group		938
		Mechanical, Electrical & Hydraulic (MEH) Engineering
				113,944
		> South Africa 2.5%
	1,973,000	Naspers		80,067
		Media in Africa & Other Emerging Markets
	4,600,000	Mr. Price		21,734
		South African Retailer of Apparel, Household & Sporting Goods
	3,049,000	Uranium One (b)		8,804
		Uranium Mines in Kazakhstan, the U.S. & Australia
				110,605
		> Israel 0.8%
	2,890,000	Israel Chemicals		37,734
		Producer of Potash, Phosphates, Bromine & Specialty Chemicals
				37,734

See accompanying notes to financial statements.

39

Columbia Acorn International

Statement of Investments, continued

Number of Shares or Principal Amount (000)			Value (000)
		> Kazakhstan 0.4%
	1,770,000	Halyk Savings Bank of Kazakhstan - GDR (b)	$	16,798
		Largest Retail Bank & Insurer in Kazakhstan
				16,798
Other Countries: Total				636,858
Latin America 5.6%
		> Brazil 3.3%
	5,000,000	Localiza Rent A Car		55,184
		Car Rental
	4,300,000	Suzano		50,075
		Brazilian Pulp & Paper Producer
	2,000,000	Natura		41,679
		Direct Retailer of Cosmetics
				146,938
		> Mexico 1.6%
	700,000	Grupo Aeroportuario del Sureste - ADR		36,267
		Mexican Airport Operator
	15,000,000	Urbi Desarrollos Urbanos (b)		33,825
		Affordable Housing Builder
				70,092
		> Chile 0.7%
	862,000	Sociedad Quimica y Minera de Chile - ADR		32,385
		Producer of Specialty Fertilizers, Lithium & Iodine
				32,385
Latin America: Total				249,415
Total Equities: 95.6% (Cost: $3,179,286)				4,235,525
Securities Lending Collateral: 0.6%
	26,644,150	Dreyfus Government Cash Management Fund (7 day yield of 0.000%) (f)		26,644
Total Securities Lending Collateral: (Cost: $26,644)				26,644
Short-Term Obligations: 3.5%
		> Repurchase Agreement 3.0%
$	131,378	Repurchase Agreement with Fixed Income Clearing Corp., dated 12/31/09, due 1/04/10 at 0.00%, collateralized by a U.S. Treasury obligation, maturing 3/18/10, market value $134,007 (repurchase proceeds $131,378)		131,378
				131,378

Principal Amount (000)			Value (000)
		> Commercial Paper 0.5%
$	21,900	Toyota Motor Credit 0.16% due 1/04/10	$	21,900
				21,900
Total Short-Term Obligations: (Amortized Cost: $153,278)				153,278
Total Investments: 99.7% (Cost: $3,359,208)(g)(h)				4,415,447
Obligation to Return Collateral for Securities Loaned: (0.6)%				(26,644	)
Cash and Other Assets Less Liabilities: 0.9%				41,935
Total Net Assets: 100.0%			$	4,430,738

ADR = American Depositary Receipts.

GDR = Global Depositary Receipts.

See accompanying notes to financial statements.

40

> Notes to Statements of Investments (dollar values in thousands)

(a)  An affiliated person of the Fund may include any company in which the Fund owns five percent or more of its outstanding voting shares. Holdings and transactions in these affiliated companies during the twelve months ended December 31, 2009, are as follows:

Affiliates	Balance of Shares Held 12/31/08		Purchases/ Additions			Sales/ Reductions		Balance of Shares Held 12/31/09		Value		Dividend
Ain Pharmaciez*		643,000		-			-		643,000	$	15,427	$	185
Koninklijke TenCate		1,556,239		78,456	**		261,706		1,372,989		36,081		725
Nippon Residential Investment		5,200		7,300			-		12,500		30,372		2,090
Unit 4 Aggresso		1,385,000		-			-		1,385,000		32,644		-
Total of Affiliated Transactions		3,589,439		85,756			261,706		3,413,489	$	114,524	$	3,000

*  At December 31, 2009, the Fund owned less than five percent of the company's outstanding voting shares.

**  Includes the effect of a 2:1 stock split.

  The aggregate cost and value of these companies at December 31, 2009, were $77,410 and $114,524, respectively. Investments in affiliated companies represented 2.6% of total net assets at December 31, 2009.

(b)  Non-income producing security.

(c)  All or a portion of this security was on loan at December 31, 2009. The total market value of Fund securities on loan at December 31, 2009 was $25,743.

(d)  Illiquid security.

(e)  Security is traded on a U.S. exchange.

(f)  Investment made with cash collateral received from securities lending activity.

(g)  At December 31, 2009, for federal income tax purposes, the cost of investments was $3,397,978 and net unrealized apppreciation was $1,017,469, consisting of gross unrealized appreciation of $1,265,386 and gross unrealized depreciation of $247,917.

(h)  On December 31, 2009, the Fund's total investments were denominated in currencies as follows:

Currency	Value		Percentage of Net Assets
Euro	$	989,294		22.3
Japanese Yen		677,448		15.3
U.S. Dollar		548,464		12.4
British Pound		305,247		6.9
Hong Kong Dollar		284,241		6.4
Other currencies less than 5% of total net assets		1,610,753		36.4
	$	4,415,447		99.7

See accompanying notes to financial statements.

41

Columbia Acorn International

Statement of Investments, continued

> Notes to Statements of Investments (dollar values in thousands)

  At December 31, 2009, the Fund had entered into the following forward foreign currency exchange contracts:

Forward Foreign Currency Exchange Contracts to Sell	Forward Foreign Currency Exchange Contracts to Buy	Principal Amount in Foreign Currency		Principal Amount in U.S. Dollar		Settlement Date	Unrealized Appreciation
USD	CAD		26,337	$	25,000	2/12/10	$	183
USD	CAD		26,474		25,000	3/15/10		313
EUR	USD		43,638		65,000	1/15/10		2,443
EUR	USD		43,678		65,000	2/12/10		2,389
EUR	USD		44,397		65,000	3/15/10		1,361
				$	245,000		$	6,689
Forward Foreign Currency Exchange Contracts to Buy	Forward Foreign Currency Exchange Contracts to Sell	Principal Amount in Foreign Currency		Principal Amount in U.S. Dollar		Settlement Date	Unrealized (Depreciation)
AUD	USD		16,544	$	15,000	1/15/10	$	(155	)
AUD	USD		16,324		15,000	2/12/10		(393	)
AUD	USD		16,531		15,000	3/15/10		(256	)
CAD	USD		25,674		25,000	1/15/10		(452	)
JPY	USD		2,234,275		25,000	1/15/10		(1,009	)
JPY	USD		2,259,250		25,000	2/12/10		(737	)
JPY	USD		2,215,575		25,000	3/15/10		(1,203	)
				$	145,000		$	(4,205	)

The counterparty for all forward foreign currency exchange contracts is State Street Bank and Trust Company.

AUD = Australian Dollar

CAD = Canadian Dollar

EUR = Euro

JPY = Japanese Yen

USD = United States Dollar

The following table summarizes the inputs used, as of December 31, 2009, in valuing the Fund's assets:

Investment Type	Quoted Prices (Level 1)		Other Significant Observable Inputs (Level 2)			Significant Unobservable Inputs (Level 3)		Total
Equities
Asia	$	63,676	$	1,652,077		$	158	$	1,715,911
Europe		35,048		1,598,293			-		1,633,341
Other Countries		366,581		270,277			-		636,858
Latin America		102,477		146,938			-		249,415
Total Equities		567,782		3,667,585			158		4,235,525
Total Securities Lending Collateral		26,644		-			-		26,644
Total Short-Term Obligations		-		153,278			-		153,278
Total Investments	$	594,426	$	3,820,863		$	158	$	4,415,447
Net Unrealized Appreciation on Forward Foreign Currency Exchange Contracts		-		6,689			-		6,689
Net Unrealized Depreciation on Forward Foreign Currency Exchange Contracts		-		(4,205	)		-		(4,205	)
Total	$	594,426	$	3,823,347		$	158	$	4,417,931

  The Fund's assets assigned to the Level 2 input category include certain foreign securities for which a third party statistical pricing service may be employed for purposes of fair market valuation.

See accompanying notes to financial statements.

42

> Notes to Statements of Investments (dollar values in thousands)

The following table reconciles asset balances for the twelve-month period ending December 31, 2009, in which significant unobservable inputs (Level 3) were used in determining value:

Investments in Securities	Balance as of December 31, 2008		Accrued Discounts/ Premiums		Realized Gain/(Loss)		Change in Unrealized Appreciation (Depreciation)			Net Purchases (Sales)		Net Transfers into (out of) Level 3		Balance as of December 31, 2009
Equities
Asia	$	312	$	-	$	-	$	(13,049	)	$	-	$	12,895	$	158
	$	312	$	-	$	-	$	(13,049	)	$	-	$	12,895	$	158

  The information in the above reconciliation table represents fiscal year to date activity for any securities identified as using Level 3 inputs during the current fiscal period.

  The change in unrealized appreciation (depreciation) attributed to securities owned at December 31, 2009, which were valued using significant unobservable inputs (Level 3) amounted to $(13,049). This amount is included in net change in unrealized appreciation on the Statements of Changes in Net Assets.

  For more information on valuation inputs, and their aggregation into the levels used in the tables above, please refer to the Security Valuation section in the accompanying Notes to Financial Statements.

See accompanying notes to financial statements.

43

Columbia Acorn International

Portfolio Diversification

At December 31, 2009, the Fund's portfolio investments as a percent of net assets were diversified as follows:

	Value (000)		Percentage of Net Assets
> Industrial Goods & Services
Other Industrial Services	$	378,257		8.5
Industrial Materials & Specialty Chemicals		306,733		6.9
Machinery		272,568		6.2
Outsourcing Services		165,223		3.7
Electrical Components		100,514		2.3
Conglomerates		76,676		1.7
Construction		66,099		1.5
Industrial Distribution		3,642		0.1
		1,369,712		30.9
> Consumer Goods & Services
Nondurables		105,466		2.4
Retail		100,417		2.3
Educational Services		79,008		1.8
Travel		76,072		1.7
Apparel		74,184		1.7
Other Consumer Services		71,062		1.6
Food & Beverage		69,684		1.6
Casinos & Gaming		67,592		1.5
Other Entertainment		52,811		1.2
Consumer Goods Distribution		27,725		0.6
Furniture & Textiles		19,704		0.4
Consumer Electronics		7,928		0.2
		751,653		17.0
> Information
Financial Processors		101,992		2.3
TV Broadcasting		80,067		1.8
Computer Hardware & Related Equipment		72,650		1.6
Instrumentation		69,182		1.6
Internet Related		54,538		1.2
Satellite Broadcasting & Services		35,724		0.8
Semiconductors & Related Equipment		34,672		0.8
Business Software		32,644		0.7
CATV		31,208		0.7
Publishing		23,168		0.5
Advertising		17,688		0.4
Business Information & Marketing Services		15,996		0.4
Telecommunications Equipment		12,203		0.3
Mobile Communications		6,690		0.2
		588,422		13.3
> Energy & Minerals
Oil Services		195,606		4.4
Mining		118,830		2.7
Oil Refining, Marketing & Distribution		86,977		2.0

	Value (000)			Percentage of Net Assets
Agricultural Commodities	$	50,075			1.1
Oil & Gas Producers		37,442			0.9
Other Resources		5,968			0.1
		494,898			11.2
> Other Industries
Real Estate		247,339			5.6
Transportation		144,236			3.2
Regulated Utilities		71,123			1.6
		462,698			10.4
> Finance
Brokerage & Money Management		168,798			3.8
Banks		112,029			2.5
Finance Companies		42,521			1.0
Savings & Loans		25,935			0.6
		349,283			7.9
> Health Care
Medical Equipment & Devices		134,085			3.0
Pharmaceuticals		35,827			0.8
Health Care Services		20,790			0.5
Medical Supplies		14,520			0.3
Biotechnology & Drug Delivery		13,637			0.3
		218,859			4.9
Total Equities:		4,235,525			95.6
Securities Lending Collateral:		26,644			0.6
Short-Term Obligations:		153,278			3.5
Total Investments:		4,415,447			99.7
Obligation to Return Collateral for Securities Loaned:		(26,644	)		(0.6	)
Cash and Other Assets Less Liabilities:		41,935			0.9
Net Assets:	$	4,430,738			100.0

See accompanying notes to financial statements.

44

Columbia Acorn USA

Major Portfolio Changes in the Fourth Quarter (Unaudited)

	Number of Shares
	09/30/09		12/31/09
Purchases
Information
AboveNet		0		45,000
Blue Coat Systems		210,100		389,100
ExlService Holdings		0		248,698
Monolithic Power Systems		340,000		500,000
PAETEC Holding		1,591,800		2,250,000
Plexus		115,000		165,000
Supertex		189,296		287,000
Consumer Goods & Services
Abercrombie & Fitch		281,000		431,000
Diamond Foods		0		97,814
Lifetime Fitness		110,000		182,000
Vail Resorts		150,000		220,000
Industrial Goods & Services
GrafTech International		200,000		540,000
Pentair		500,000		585,000
Energy & Minerals
Atwood Oceanics		720,000		755,000
Bristow		0		105,000
Health Care
Acorda Therapeutics		0		199,000
Allos Therapeutics		341,000		565,000
Gen-Probe		0		46,500
Mednax		0		45,000
Nanosphere		0		199,720

	Number of Shares
	09/30/09		12/31/09
Sales
Information
Amphenol		295,600		285,600
Cogent Communications		840,000		444,800
Concur Technologies		223,000		158,000
Micros Systems		695,100		620,000
Polycom		525,000		480,000
Switch & Data Facilities		947,000		510,000
Consumer Goods & Services
Hot Topic		497,714		0
Jarden		298,000		154,000
Industrial Goods & Services
Greif		50,000		0
Mine Safety Appliances		155,000		77,000
Quanta Services		350,000		110,000
Energy & Minerals
FMC Technologies		598,400		500,000
Oceaneering International		130,111		95,000
Health Care
Cephalon		125,000		56,000
Charles River Laboratories		67,000		0
Emdeon		148,000		0
Human Genome Sciences		335,000		298,000
InterMune		187,000		127,800
Luminex		205,000		0
Myriad Genetics		153,466		113,466
Nektar Therapeutics		500,000		357,000
Onyx Pharmaceuticals		75,000		0
Poniard		290,184		0
Psychiatric Solutions		287,000		170,000
Other Industries
Heartland Express		524,720		344,720

See accompanying notes to financial statements.

45

Columbia Acorn USA

Statement of Investments, December 31, 2009

Number of Shares			Value (000)
				Equities: 99.7%
Information 35.4%
		> Business Software 7.7%
	1,155,000	Informatica (a)	$	29,868
		Enterprise Data Integration Software
	620,000	Micros Systems (a)		19,239
		Information Systems for Restaurants & Hotels
	375,000	ANSYS (a)		16,297
		Simulation Software for Engineers & Designers
	525,000	Blackbaud		12,406
		Software & Services for Non-profits
	2,100,000	Novell (a)		8,715
		Directory, Operating System & Identity Management Software
	158,000	Concur Technologies (a)		6,755
		Web Enabled Cost & Expense Management Software
	240,000	NetSuite (a)(b)		3,835
		End to End IT Systems Solutions Delivered Over the Web
	57,000	Quality Systems		3,578
		IT Systems for Medical Groups & Ambulatory Care Centers
	108,213	Tyler Technologies (a)		2,155
		Financial, Tax, Court & Document Management Systems for Government
	307,352	Art Technology Group (a)		1,386
		Software & Tools to Optimize Websites for E-commerce
	100,000	Avid Technology (a)		1,276
		Digital Nonlinear Editing Software & Systems
	230,000	Actuate (a)		984
		Information Delivery Software & Solutions
	10,800	Blackboard (a)		490
		Education Software
				106,984
		> Semiconductors & Related Equipment 4.4%
	760,000	Microsemi (a)		13,490
		Analog/Mixed-signal Semiconductors
	500,000	Monolithic Power Systems (a)		11,985
		High Performance Analog & Mixed-signal Integrated Circuits (ICs)
	1,179,750	ON Semiconductor (a)		10,394
		Mixed-signal & Power Management Semiconductors
	287,000	Supertex (a)		8,553
		Analog/Mixed-signal Semiconductors
	1,168,000	Integrated Device Technology (a)		7,557
		Communications Semiconductors
	480,000	Pericom Semiconductor (a)		5,534
		Interface Integrated Circuits (ICs) & Frequency Control Products
	750,000	Entegris (a)		3,960
		Semiconductor Materials Management Products
				61,473
		> Mobile Communications 3.8%
	1,250,000	Crown Castle International (a)		48,800
		Communications Towers

Number of Shares			Value (000)
	130,000	SBA Communications (a)	$	4,441
		Communications Towers
	88,000	Globalstar (a)(b)		76
		Satellite Mobile Voice & Data Carrier
				53,317
		> Telephone and Data Services 3.8%
	2,061,000	tw telecom (a)		35,326
		Fiber Optic Telephone/Data Services
	2,250,000	PAETEC Holding (a)		9,337
		Telephone/Data Services for Business
	444,800	Cogent Communications (a)		4,386
		Internet Data Pipelines
	45,000	AboveNet (a)		2,927
		Metropolitan Fiber Communications Services
				51,976
		> Instrumentation 3.4%
	180,000	Mettler Toledo (a)		18,898
		Laboratory Equipment
	775,000	IPG Photonics (a)		12,973
		Fiber Lasers
	350,000	FLIR Systems (a)		11,452
		Infrared Cameras
	168,000	Trimble Navigation (a)		4,234
		GPS-based Instruments
				47,557
		> Computer Hardware & Related Equipment 3.3%
	505,000	II-VI (a)		16,059
		Laser Optics & Specialty Materials
	285,600	Amphenol		13,189
		Electronic Connectors
	280,000	Nice Systems - ADR (Israel) (a)		8,691
		Audio & Video Recording Solutions
	184,000	Zebra Technologies (a)		5,219
		Bar Code Printers
	135,000	Netgear (a)		2,928
		Networking Products for Small Business & Home
				46,086
		> Telecommunications Equipment 2.3%
	480,000	Polycom (a)		11,986
		Video Conferencing Equipment
	389,100	Blue Coat Systems (a)		11,105
		WAN Acceleration & Network Security
	335,000	CommScope (a)		8,887
		Wireless Infrastructure Equipment & Telecom Cable
				31,978
		> Financial Processors 1.8%
	463,000	Global Payments		24,937
		Credit Card Processor
				24,937
		> Gaming Equipment & Services 1.7%
	570,000	Bally Technologies (a)		23,535
		Slot Machines & Software
				23,535

See accompanying notes to financial statements.

46

Number of Shares			Value (000)
		> Computer Services 1.4%
	395,000	SRA International (a)	$	7,545
		Government IT Services
	248,698	ExlService Holdings (a)		4,516
		Business Process Outsourcing
	1,005,500	Hackett Group (a)		2,795
		IT Integration & Best Practice Research
	235,000	iGate		2,350
		IT & Business Process Outsourcing Services
	786,000	RCM Technologies (a)(c)		1,949
		Technology & Engineering Services
				19,155
		> Internet Related 0.8%
	510,000	Switch & Data Facilities (a)		10,307
		Network Neutral Data Centers
	381,740	TheStreet.com		916
		Financial Information Websites
				11,223
		> Contract Manufacturing 0.3%
	165,000	Plexus (a)		4,703
		Electronic Manufacturing Services
				4,703
		> Radio 0.3%
	511,100	Salem Communications (a)		3,062
		Radio Stations for Religious Programming
	705,500	Spanish Broadcasting System (a)		550
		Spanish Language Radio Stations
	18,750	Saga Communications (a)		235
		Radio Stations in Small & Mid-sized Cities
				3,847
		> TV Broadcasting 0.3%
	975,000	Entravision Communications (a)		3,315
		Spanish Language TV & Radio Stations
				3,315
		> CATV 0.1%
	335,000	Mediacom Communications (a)		1,498
		Cable Television Franchises
				1,498
Information: Total				491,584
Consumer Goods & Services 16.6%
		> Retail 6.1%
	431,000	Abercrombie & Fitch		15,021
		Teen Apparel Retailer
	402,000	Urban Outfitters (a)		14,066
		Apparel & Home Specialty Retailer
	281,000	J Crew Group (a)		12,572
		Multi-channel Branded Retailer
	390,000	lululemon athletica (a)		11,739
		Premium Active Apparel Retailer
	824,000	Chico's FAS (a)		11,577
		Women's Specialty Retailer
	875,000	Saks (a)		5,740
		Luxury Department Store Retailer
	480,000	Talbots (a)(b)		4,277
		Women's Specialty Retailer

Number of Shares			Value (000)
	658,000	Charming Shoppes (a)	$	4,257
		Women's Specialty Plus Size Apparel Retailer
	55,000	Gymboree (a)		2,392
		Children's Apparel Specialty Retailer
	165,000	AnnTaylor Stores (a)		2,251
		Women's Apparel Retailer
	17,100	Rue21 (a)		480
		Fashion Value Apparel Retailer
				84,372
		> Travel 3.1%
	750,000	Gaylord Entertainment (a)		14,813
		Convention Hotels
	797,750	Avis Budget Group (a)		10,466
		Second Largest Car Rental Company
	750,000	Hertz (a)		8,940
		Largest U.S. Rental Car Operator
	220,000	Vail Resorts (a)		8,316
		Ski Resort Operator & Developer
				42,535
		> Educational Services 1.6%
	192,000	ITT Educational Services (a)		18,424
		Post-secondary Degree Services
	165,000	Universal Technical Institute (a)		3,333
		Vocational Training
				21,757
		> Furniture & Textiles 1.4%
	980,000	Knoll		10,124
		Office Furniture
	285,000	Herman Miller		4,554
		Office Furniture
	540,000	Interface		4,487
		Modular & Broadloom Carpet
				19,165
		> Apparel 1.0%
	222,200	Coach		8,117
		Designer & Retailer of Branded Leather Accessories
	284,313	True Religion Apparel (a)		5,257
		Premium Denim
				13,374
		> Other Durable Goods 0.8%
	327,900	Cavco Industries (a)(c)		11,778
		Manufactured Homes
				11,778
		> Consumer Goods Distribution 0.7%
	523,500	Pool		9,988
		Distributor of Swimming Pool Supplies & Equipment
				9,988
		> Food & Beverage 0.5%
	97,814	Diamond Foods		3,476
		Culinary Ingredients & Snack Foods
	90,000	Hansen Natural (a)		3,456
		Alternative Beverages
				6,932

See accompanying notes to financial statements.

47

Columbia Acorn USA

Statement of Investments, continued

Number of Shares			Value (000)
		> Leisure Products 0.4%
	180,000	Thor Industries	$	5,652
		RV & Bus Manufacturer
				5,652
		> Nondurables 0.3%
	154,000	Jarden		4,760
		Branded Household Products
				4,760
		> Other Consumer Services 0.3%
	182,000	Lifetime Fitness (a)(b)		4,537
		Sport & Fitness Club Operator
				4,537
		> Casinos & Gaming 0.3%
	455,000	Pinnacle Entertainment (a)		4,086
		Regional Casino Operator
				4,086
		> Restaurants 0.1%
	40,000	P.F. Chang's China Bistro (a)(b)		1,517
		Mandarin Style Restaurants
				1,517
Consumer Goods & Services: Total				230,453
Industrial Goods & Services 13.3%
		> Machinery 9.4%
	627,500	Ametek		23,996
		Aerospace/Industrial Instruments
	373,600	Nordson		22,857
		Dispensing Systems for Adhesives & Coatings
	587,000	ESCO Technologies		21,044
		Automatic Electric Meter Readers
	445,000	Donaldson		18,930
		Industrial Air Filtration
	585,000	Pentair		18,895
		Pumps & Water Treatment
	235,000	Oshkosh		8,702
		Specialty Truck Manufacturer
	195,000	MOOG (a)		5,700
		Motion Control Products for Aerospace, Defense & Industrial Markets
	100,000	HEICO		3,596
		FAA Approved Aircraft Replacement Parts
	71,800	Toro		3,002
		Turf Maintenance Equipment
	77,000	Mine Safety Appliances		2,043
		Safety Equipment
	50,000	Kaydon		1,788
		Specialized Friction & Motion Control Products
				130,553
		> Industrial Materials & Specialty Chemicals 0.9%
	255,000	Drew Industries (a)		5,266
		RV & Manufactured Home Components
	150,000	Albany International		3,369
		Paper Machine Clothing & Advanced Textiles
	60,000	Albemarle		2,182
		Refinery Catalysts & Other Specialty Chemicals

Number of Shares			Value (000)
	65,000	Koppers Holdings	$	1,979
		Integrated Provider of Carbon Compounds
				12,796
		> Steel 0.6%
	540,000	GrafTech International (a)		8,397
		Industrial Graphite Materials Producer
				8,397
		> Other Industrial Services 0.5%
	265,000	TrueBlue (a)		3,925
		Temporary Manual Labor
	396,000	American Reprographics (a)		2,776
		Document Management & Logistics
				6,701
		> Industrial Distribution 0.4%
	350,000	Interline Brands (a)		6,044
		Industrial Distribution
				6,044
		> Electrical Components 0.4%
	145,000	Acuity Brands		5,168
		Commercial Lighting Fixtures
				5,168
		> Construction 0.4%
	240,000	M/I Homes (a)		2,494
		Columbus-based Home Builder
	110,000	Ritchie Brothers Auctioneers (b)		2,467
		Heavy Equipment Auctioneer
				4,961
		> Waste Management 0.3%
	130,000	Waste Connections (a)		4,334
		Solid Waste Management
				4,334
		> Water 0.2%
	550,000	Mueller Water Products		2,860
		Fire Hydrants, Valves & Ductile Iron Pipes
				2,860
		> Outsourcing Services 0.2%
	110,000	Quanta Services (a)		2,292
		Electrical & Telecom Construction Services
				2,292
Industrial Goods & Services: Total				184,106
Finance 12.5%
		> Finance Companies 5.1%
	1,136,500	AmeriCredit (a)		21,639
		Auto Lending
	407,900	World Acceptance (a)		14,615
		Personal Loans
	365,000	GATX		10,494
		Rail Car Lessor
	345,000	McGrath Rentcorp		7,714
		Temporary Space & IT Rentals
	275,000	Aaron's (b)		7,626
		Rent to Own
	625,000	H&E Equipment Services (a)		6,556
		Heavy Equipment Leasing

See accompanying notes to financial statements.

48

Number of Shares			Value (000)
		> Finance Companies—continued
	230,000	CAI International (a)	$	2,077
		International Container Leasing
	99,200	Marlin Business Services (a)		786
		Small Equipment Leasing
				71,507
		> Banks 4.4%
	935,182	Valley National Bancorp (b)		13,214
		New Jersey/New York Bank
	492,125	MB Financial		9,705
		Chicago Bank
	659,800	TCF Financial		8,986
		Great Lakes Bank
	403,788	Lakeland Financial		6,965
		Indiana Bank
	508,000	Pacific Continental		5,811
		Pacific N.W. Bank
	127,200	SVB Financial Group (a)		5,303
		Bank to Venture Capitalists
	213,600	Associated Banc-Corp		2,352
		Midwest Bank
	215,000	Eagle Bancorp (a)		2,251
		Metro D.C. Bank
	500,000	First Busey		1,945
		Illinois Bank
	140,000	Wilmington Trust		1,728
		Delaware Trust Bank
	90,000	TriCo Bancshares		1,498
		California Central Valley Bank
	851,247	Guaranty Bancorp (a)		1,124
		Colorado Bank
	247,203	Green Bankshares (b)		878
		Tennessee Bank
				61,760
		> Brokerage & Money Management 1.4%
	280,000	Eaton Vance		8,515
		Specialty Mutual Funds
	750,000	MF Global (a)		5,212
		Futures Broker
	155,000	Investment Technology Group (a)		3,054
		Electronic Trading
	150,000	SEI Investments		2,628
		Mutual Fund Administration & Investment Management
				19,409
		> Savings & Loans 1.0%
	600,000	ViewPoint Financial		8,646
		Texas Thrift
	238,090	Berkshire Hills Bancorp		4,924
		Northeast Thrift
	42,231	K-Fed Bancorp (b)		371
		Los Angeles Savings & Loan
				13,941
		> Insurance 0.6%
	120,000	Tower Group		2,809
		Commercial & Personal Lines Insurance

Number of Shares			Value (000)
	110,000	Delphi Financial Group	$	2,461
		Workers Compensation & Group Employee Benefit Products & Services
	7,000	Markel (a)		2,380
		Specialty Insurance
				7,650
Finance: Total				174,267
Energy & Minerals 8.9%
		> Oil Services 5.0%
	500,000	FMC Technologies (a)		28,920
		Oil & Gas Wellhead Manufacturer
	755,000	Atwood Oceanics (a)		27,067
		Offshore Drilling Contractor
	95,000	Oceaneering International (a)		5,559
		Provider of Sub-sea Services & Manufactured Products
	105,000	Bristow (a)		4,037
		Largest Provider of Helicopter Services to Offshore Oil & Gas Producers
	115,375	Exterran Holdings (a)		2,475
		Natural Gas Compressor Rental & Fabrication
	106,000	Tesco (a)		1,369
		Developing New Well Drilling Technologies
				69,427
		> Oil & Gas Producers 3.0%
	925,000	Quicksilver Resources (a)		13,884
		Natural Gas & Coal Steam Gas Producer
	485,000	Carrizo Oil & Gas (a)		12,848
		Oil & Gas Producer
	218,800	Southwestern Energy (a)		10,546
		Oil & Gas Producer
	111,200	Equitable Resources		4,884
		Natural Gas Producer & Utility
				42,162
		> Mining 0.5%
	50,000	Core Laboratories (Netherlands)		5,906
		Oil & Gas Reservoir Consulting
	143,247	PolyMet Mining (a)		438
		Copper & Nickel Miner
				6,344
		> Other Resources 0.4%
	218,000	Layne Christensen (a)		6,259
		Oil & Gas Production/Engineering & Construction/Contract Drilling
				6,259
Energy & Minerals: Total				124,192
Health Care 8.4%
		> Biotechnology & Drug Delivery 3.6%
	298,000	Human Genome Sciences (a)		9,119
		Biotech Focused on HCV, Inflammation & Cancer
	199,000	Acorda Therapeutics (a)		5,019
		Biopharma Company Focused on Nervous Disorder Drugs
	266,000	BioMarin (a)		5,003
		Biotech Focused on Orphan Diseases

See accompanying notes to financial statements.

49

Columbia Acorn USA

Statement of Investments, continued

Number of Shares			Value (000)
		> Biotechnology & Drug Delivery—continued
	488,784	Seattle Genetics (a)	$	4,966
		Antibody-based Therapies for Cancer
	157,000	Auxilium Pharmaceuticals (a)		4,707
		Biotech Focused on Niche Disease Areas
	565,000	Allos Therapeutics (a)		3,712
		Cancer Drug Development
	65,000	United Therapeutics (a)		3,422
		Biotech Focused on Rare Diseases
	357,000	Nektar Therapeutics (a)		3,327
		Drug Delivery Technologies
	85,000	AMAG Pharmaceuticals (a)		3,233
		Biotech Focused on Niche Diseases
	113,466	Myriad Genetics (a)		2,961
		Genetic Diagnostics
	500,000	NPS Pharmaceuticals (a)		1,700
		Orphan Drugs & Healthy Royalties
	127,800	InterMune (a)		1,667
		Drugs for Pulmonary Fibrosis & Hepatitis C
	225,000	Micromet (a)(b)		1,499
		Next-generation Antibody Technology
	18,181	Metabolex, Series A-1 (a)(d)		22
		Diabetes Drug Development
	738,060	Medicure - Warrants (a)(d)		7
		Cardiovascular Biotech Company
	100,000	IsoRay - Warrants (a)(d)		2
		Radiology Cancer Company
	37,500	Locus Pharmaceuticals, Series A-1, Pfd. (a)(d)		2
	19,329	Locus Pharmaceuticals, Series B-1, Pfd. (a)(d)		1
		High Throughput Rational Drug Design
				50,369
		> Medical Equipment & Devices 2.0%
	235,000	Alexion Pharmaceuticals (a)		11,473
		Biotech Focused on Orphan Diseases
	134,000	Illumina (a)		4,107
		Leading Tools & Service Provider for Genetic Analysis
	85,000	Orthofix International (a)		2,632
		Bone Fixation & Stimulation Devices
	80,000	Sirona Dental Systems (a)		2,539
		Manufacturer of Dental Equipment
	46,500	Gen-Probe (a)		1,995
		Molecular In-vitro Diagnostics
	100,000	American Medical Systems (a)		1,929
		Medical Devices to Treat Urological Conditions
	40,000	Kinetic Concepts (a)		1,506
		Wound Healing & Tissue Repair Products
	199,720	Nanosphere (a)		1,286
		Molecular Diagnostics Company with Best of Breed Platform
				27,467
		> Health Care Services 1.6%
	606,300	PSS World Medical (a)		13,684
		Distributor of Medical Supplies
	170,000	Psychiatric Solutions (a)		3,594
		Behavioral Health Services

Number of Shares			Value (000)
	45,000	Mednax (a)	$	2,705
		Physician Management for Pediatric & Anesthesia Practices
	283,000	eResearch Technology (a)		1,701
		Clinical Research Services
				21,684
		> Medical Supplies 1.0%
	318,000	Cepheid (a)		3,969
		Molecular Diagnostics
	180,000	Immucor (a)		3,643
		Automated Blood Typing Reagents
	43,000	Techne		2,948
		Cytokines, Antibodies & Other Reagents for Life Science
	53,000	Idexx Laboratories (a)(b)		2,832
		Diagnostic Equipment & Services for Veterinarians
				13,392
		> Pharmaceuticals 0.2%
	56,000	Cephalon (a)		3,495
		Specialty Pharmaceuticals for Pain, Central Nervous System & Oncology
				3,495
Health Care: Total				116,407
Other Industries 4.6%
		> Real Estate 4.1%
	405,000	SL Green Realty		20,347
		Manhattan Office Buildings
	276,796	Macerich (b)		9,951
		Regional Shopping Malls
	170,000	Corporate Office Properties		6,227
		Office Buildings
	1,450,000	Kite Realty Group		5,902
		Community Shopping Centers
	100,000	Digital Realty Trust		5,028
		Technology-focused Office Buildings
	90,000	American Campus Communities		2,529
		Student Housing
	470,000	DCT Industrial Trust		2,359
		Industrial Properties
	196,000	Extra Space Storage		2,264
		Self Storage Facilities
	120,000	BioMed Realty Trust		1,894
		Life Science-focused Office Buildings
				56,501
		> Transportation 0.5%
	344,720	Heartland Express		5,264
		Regional Trucker
	180,000	Rush Enterprises, Class A (a)		2,140
		Truck Sales & Services
				7,404
Other Industries: Total				63,905
Total Equities: 99.7% (Cost: $1,099,805)				1,384,914

See accompanying notes to financial statements.

50

Number of Shares or Principal Amount (000)			Value (000)
Securities Lending Collateral: 1.2%
	16,749,043	Dreyfus Government Cash Management Fund (e) (7 day yield of 0.000%)	$	16,749
Total Securities Lending Collateral: (Cost: $16,749)				16,749
Short-Term Obligation: 0.8%
		> Repurchase Agreement 0.8%
$	11,015	Repurchase Agreement with Fixed Income Clearing Corp., dated 12/31/09, due 1/04/10 at 0.00%, collateralized by a U.S. Treasury obligation, maturing 3/18/10, market value $11,239 (repurchase proceeds $11,015)		11,015
Total Short-Term Obligation: (Cost: $11,015)				11,015
Total Investments: 101.7% (Cost: $1,127,569)(f)				1,412,678
Obligation to Return Collateral for Securities Loaned: (1.2)%				(16,749	)
Cash and Other Assets Less Liabilities: (0.5)%				(6,320	)
Total Net Assets: 100.0%			$	1,389,609

ADR = American Depositary Receipts

See accompanying notes to financial statements.

51

Columbia Acorn USA

Statement of Investments, continued

> Notes to Statement of Investments (dollar values in thousands)

(a)  Non-income producing security.

(b)  All or a portion of this security was on loan at December 31, 2009. The total market value of Fund securities on loan at December 31, 2009 was $16,200.

(c)  An affiliated person of the Fund may include any company in which the Fund owns five percent or more of its outstanding voting shares. Holdings and transactions in these affiliated companies during the twelve months ended December 31, 2009, are as follows:

Affiliate	Balance of Shares Held 12/31/08		Purchases/ Additions		Sales/ Reductions		Balance of Shares Held 12/31/09		Value		Dividend
RCM Technologies		786,000		-		-		786,000	$	1,949	$	-
Cavco Industries		287,900		50,000		10,000		327,900		11,778		-
Total of Affiliated Transactions		1,073,900		50,000		10,000		1,113,900	$	13,727	$	-

  The aggregate cost and value of these companies at December 31, 2009, were $16,520 and $13,727, respectively. Investments in the affiliated companies represented 1.0% of total net assets at December 31, 2009.

(d)  Denotes a restricted security, which is subject to restrictions on resale under federal securities laws. These securities are valued at a fair value determined in good faith under consistently applied procedures established by the Board of Trustees. At December 31, 2009, the market value of these securities amounted to $34 which represented less than 0.01% of total net assets.

  Additional information on these securities is as follows:

Security	Acquisition Dates	Shares		Cost		Value
Metabolex, Series A	2/11/00		18,181	$	2,000	$	22
Medicure - Warrants	12/22/06		738,060		-		7
IsoRay - Warrants	3/21/07		100,000		-		2
Locus Pharmaceuticals, Series A-1, Pfd.	9/05/01		37,500		1,500		2
Locus Pharmaceuticals, Series B-1, Pfd.	2/08/07		19,329		56		1
				$	3,556	$	34

(e)  Investment made with cash collateral received from securities lending activity.

(f)  At December 31, 2009, for federal income tax purposes, the cost of investments was $1,127,912 and net unrealized appreciation was $284,766, consisting of gross unrealized appreciation of $457,844 and gross unrealized depreciation of $173,078.

  The following table summarizes the inputs used, as of December 31, 2009, in valuing the Fund's assets:

Investment Type	Quoted Prices (Level 1)		Other Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Equities
Information	$	491,584	$	-	$	-	$	491,584
Consumer Goods & Services		230,453		-		-		230,453
Industrial Goods & Services		184,106		-		-		184,106
Finance		174,267		-		-		174,267
Energy & Minerals		124,192		-		-		124,192
Health Care		116,373		9		25		116,407
Other Industries		63,905		-		-		63,905
Total Equities		1,384,880		9		25		1,384,914
Total Securities Lending Collateral		16,749		-		-		16,749
Short-Term Obligation		-		11,015		-		11,015
Total Investments	$	1,401,629	$	11,024	$	25	$	1,412,678

  The Fund's assets assigned to the Level 2 input category include certain foreign securities for which a third party statistical pricing service may be employed for purposes of fair market valuation.

See accompanying notes to financial statements.

52

> Notes to Statement of Investments (dollar values in thousands)

  The following table reconciles asset balances for the twelve-month period ending December 31, 2009, in which significant unobservable inputs (Level 3) were used in determining value:

Investments in Securities	Balance as of December 31, 2008		Accrued Discounts/ Premiums		Realized Gain/(Loss)		Change in Unrealized Appreciation (Depreciation)			Net Purchases (Sales)		Net Transfers into (out of) Level 3		Balance as of December 31, 2009
Equities
Health Care	$	41	$	-	$	-	$	(16	)	$	-	$	-	$	25
	$	41	$	-	$	-	$	(16	)	$	-	$	-	$	25

  The information in the above reconciliation table represents fiscal year to date activity for any securities identified as using Level 3 during the current fiscal period.

  The change in unrealized appreciation (depreciation) attributed to securities owned at December 31, 2009, which were valued using significant unobservable inputs (Level 3) amounted to $(16). This amount is included in net change in unrealized depreciation on the Statements of Changes in Net Assets.

  For more information on valuation inputs, and their aggregation into the levels used in the tables above, please refer to the Security Valuation section in the accompanying Notes to Financial Statements.

See accompanying notes to financial statements.

53

Columbia Acorn International Select

Major Portfolio Changes in the Fourth Quarter (Unaudited)

	Number of Shares
	09/30/09		12/31/09
Purchases
Europe
> United Kingdom
Cobham		2,115,000		2,650,000
Schroders		270,000		310,000
Spice Group		0		1,502,200
> Netherlands
Smit Internationale		0		38,285
> France
Eutelsat (France)		138,000		188,000
> Germany
Wirecard		0		635,000
> Spain
Red Electrica de Espana (Spain)		175,000		195,000
> Switzerland
Bank Sarasin & Cie		24,800		90,000
Asia
> Japan
Ain Pharmaciez		95,300		160,000
Nomura Holdings		0		560,000
> Singapore
Olam International (Singapore)		5,500,000		6,100,000
> China
Zhaojin Mining Industry (China)		0		3,711,000
Other Countries
> Australia
United Group		0		487,000

	Number of Shares
	09/30/09		12/31/09
Sales
Europe
> United Kingdom
RPS Group		1,200,000		0
> France
SES		210,000		0
> Germany
Wincor Nixdorf		110,000		0
Asia
> Japan
Aeon Mall		296,000		0
> Hong Kong
NagaCorp (Hong Kong)		9,918,766		3,867,066
Other Countries
> Canada
Potash Corp. of Saskatchewan		117,400		80,000
> United States
Alexion Pharmaceuticals		220,000		90,000
Cephalon		85,000		0
> Israel
Israel Chemicals		1,203,000		310,000

See accompanying notes to financial statements.

54

Columbia Acorn International Select

Statement of Investments, December 31, 2009

Number of Shares			Value (000)
				Equities: 93.3%
Europe 36.9%
		> United Kingdom 15.2%
	2,350,000	Serco	$	19,979
		Facilities Management
	1,100,000	Capita Group		13,268
		White Collar, Back Office Outsourcing
	2,650,000	Cobham		10,682
		Aerospace Components
	525,000	Intertek Group		10,571
		Testing, Inspection & Certification Services
	310,000	Schroders		6,617
		United Kingdom Top Tier Asset Manager
	1,502,200	Spice Group		1,466
		United Kingdom Utility Outsourcing
				62,583
		> Netherlands 6.0%
	169,162	Fugro		9,660
		Sub-sea Oilfield Services
	252,000	Imtech		6,763
		Electromechanical & ICT Installation & Maintenance
	41,000	Core Laboratories		4,843
		Oil & Gas Reservoir Consulting
	38,285	Smit Internationale		3,296
		Harbor & Offshore Towage & Marine Services
				24,562
		> France 4.3%
	89,500	Neopost		7,394
		Postage Meter Machines
	188,000	Eutelsat		6,032
		Fixed Satellite Services
	102,000	Zodiac Aerospace		4,257
		Leading Supplier to the Aerospace Industry
				17,683
		> Germany 3.2%
	635,000	Wirecard		8,730
		Online Payment Processing & Risk Management
	174,000	Rhoen-Klinikum		4,256
		Health Care Services
				12,986
		> Spain 2.6%
	195,000	Red Electrica de Espana		10,807
		Spanish Power Transmission
				10,807
		> Sweden 2.4%
	669,000	Hexagon		9,827
		Measurement Equipment
				9,827
		> Switzerland 1.7%
	35,700	Kuehne & Nagel		3,454
		Freight Forwarding/Logistics
	90,000	Bank Sarasin & Cie (a)		3,401
		Private Banking
				6,855

Number of Shares			Value (000)
		> Ireland 0.8%
	1,130,000	United Drug	$	3,448
		Irish Pharmaceutical Wholesaler & Outsourcer
				3,448
		> Denmark 0.7%
	29,000	Novozymes		3,007
		Industrial Enzymes
				3,007
Europe: Total				151,758
Asia 35.1%
		> Japan 14.6%
	1,277,000	Kansai Paint		10,603
		Paint Producer in Japan, India, China & Southeast Asia
	9,000	Jupiter Telecommunications		8,916
		Largest Cable Service Provider in Japan
	189,300	Benesse		7,916
		Education Service Provider
	634,300	Rohto Pharmaceutical		7,301
		Health & Beauty Products
	3,540	Seven Bank		7,031
		ATM Processing Services
	900	Orix JREIT		4,473
		Diversified REIT
	560,000	Nomura Holdings		4,127
		Brokerage, Dealing, Underwriting & Asset Management
	160,000	Ain Pharmaciez		3,839
		Dispensing Pharmacy/Drugstore Operator
	435,000	Kamigumi		3,161
		Port Cargo Handling & Logistics
	307,000	Suruga Bank		2,663
		Regional Bank
				60,030
		> Singapore 6.6%
	7,500,000	Ascendas REIT		11,745
		Singapore Industrial Property Landlord
	6,100,000	Olam International		11,424
		Agriculture Supply Chain Manager
	702,000	Singapore Exchange		4,138
		Singapore Equity & Derivatives Market Operator
				27,307
		> South Korea 6.6%
	73,100	NHN (a)		12,071
		South Korea's Largest Online Search Engine
	49,204	MegaStudy		10,082
		Online Education Service Provider
	151,000	Woongjin Coway		4,978
		South Korean Household Appliance Rental Service Provider
				27,131
		> China 4.7%
	3,711,000	Zhaojin Mining Industry		7,320
		Gold Mining & Refining in China
	6,731,000	Jiangsu Expressway		5,988
		Chinese Toll Road Operator

See accompanying notes to financial statements.

55

Columbia Acorn International Select

Statement of Investments, continued

Number of Shares			Value (000)
		> China—continued
	1,752,700	Shandong Weigao	$	5,821
		Vertically Integrated Hospital Consumable Manufacturer
				19,129
		> Hong Kong 2.6%
	434,700	Hong Kong Exchanges and Clearing		7,739
		Hong Kong Equity & Derivatives Market Operator
	1,259,800	Lifestyle International		2,337
		Mid to High-end Department Store Operator in Hong Kong & China
	3,867,066	NagaCorp		427
		Casino/Entertainment Complex in Cambodia
				10,503
Asia: Total				144,100
Other Countries 21.3%
		> Canada 7.9%
	701,250	Eldorado Gold (a)		10,004
		Gold Miner in Turkey, Greece, China & Brazil
	615,000	Pacific Rubiales Energy (a)		9,085
		Oil Production & Exploration in Colombia
	80,000	Potash Corp. of Saskatchewan		8,680
		World's Largest Producer of Potash
	172,000	CCL Industries		4,646
		Leading Global Label Manufacturer
				32,415
		> South Africa 6.2%
	630,000	Naspers		25,566
		Media in Africa & Other Emerging Markets
				25,566
		> United States 4.7%
	61,000	Diamond Offshore		6,004
		Offshore Drilling Contractor
	80,000	Oceaneering International (a)		4,681
		Provider of Sub-sea Services & Manufactured Products
	90,000	Alexion Pharmaceuticals (a)		4,394
		Biotech Focused on Orphan Diseases
	115,000	Atwood Oceanics (a)		4,123
		Offshore Drilling Contractor
				19,202
		> Australia 1.5%
	487,000	United Group		6,201
		Engineering & Facilities Management
				6,201
		> Israel 1.0%
	310,000	Israel Chemicals		4,048
		Producer of Potash, Phosphates, Bromine & Specialty Chemicals
				4,048
Other Countries: Total				87,432
Total Equities: 93.3% (Cost: $302,588)				383,290

Number of Shares or Principal Amount (000)			Value (000)
Exchange Traded Fund: 1.0%
	325,000	iShares MSCI Taiwan Index Fund	$	4,215
		Taiwan Exchange Traded Fund
Total Exchange Traded Fund: (Cost: $3,231)				4,215
Short-Term Obligations: 5.9%
		> Repurchase Agreement 5.4%
$	21,979	Repurchase Agreement with Fixed Income Clearing Corp., dated 12/31/09, due 1/04/10 at 0.00%, collateralized by a U.S. Treasury obligation, maturing 3/18/10, market value $22,423 (repurchase proceeds $21,979)		21,979
				21,979
		> Commercial Paper 0.5%
	2,000	Toyota Motor Credit 0.16% due 1/04/10		2,000
				2,000
Total Short-Term Obligations: (Amortized Cost: $23,979)				23,979
Total Investments: 100.2% (Cost: $329,798)(b)(c)				411,484
Cash and Other Assets Less Liabilities: (0.2)%				(809	)
Total Net Assets: 100.0%			$	410,675

See accompanying notes to financial statements.

56

> Notes to Statement of Investments (dollar values in thousands)

(a)  Non-income producing security.

(b)  At December 31, 2009, for federal income tax purposes, the cost of investments was $333,882 and net unrealized appreciation was $77,602, consisting of gross unrealized appreciation of $87,792 and gross unrealized depreciation of $10,190.

(c)  On December 31, 2009, the Fund's total investments were denominated in currencies as follows:

Currency	Value		Percentage of Net Assets
Euro	$	64,643		15.8
British Pound		62,583		15.2
U.S. Dollar		60,919		14.8
Japanese Yen		60,030		14.6
Hong Kong Dollar		29,632		7.2
Singapore Dollar		27,307		6.7
South Korean Won		27,131		6.6
South African Rand		25,566		6.2
Canadian Dollar		23,735		5.8
Other currencies less than 5% of total net assets		29,938		7.3
	$	411,484		100.2

  The following table summarizes the inputs used, as of December 31, 2009, in valuing the Fund's assets:

Investment Type	Quoted Prices (Level 1)		Other Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Equities
Europe	$	4,843	$	146,915	$	-	$	151,758
Asia		-		144,100		-		144,100
Other Countries		51,617		35,815		-		87,432
Total Equities		56,460		326,830		-		383,290
Total Exchange Traded Fund		4,215		-		-		4,215
Total Short-Term Obligations		-		23,979		-		23,979
Total Investments	$	60,675	$	350,809	$	-	$	411,484

  The Fund's assets assigned to the Level 2 input category include certain foreign securities for which a third party statistical pricing service may be employed for purposes of fair market valuation.

  For more information on valuation inputs, and their aggregation into the levels used in the table above, please refer to the Security Valuation section in the accompanying Notes to Financial Statements.

See accompanying notes to financial statements.

57

Columbia Acorn International Select

Portfolio Diversification

At December 31, 2009, the Fund's portfolio investments as a percent of net assets were diversified as follows:

	Value (000)		Percentage of Net Assets
> Industrial Goods & Services
Outsourcing Services	$	46,137		11.2
Other Industrial Services		31,246		7.6
Industrial Materials & Specialty Chemicals		17,658		4.3
Electrical Components		10,682		2.6
Machinery		7,394		1.8
		113,117		27.5
> Information
TV Broadcasting		25,566		6.2
Financial Processors		20,607		5.0
Internet Related		12,071		3.0
Instrumentation		9,827		2.4
CATV		8,916		2.2
Satellite Broadcasting & Services		6,032		1.5
		83,019		20.3
> Energy & Minerals
Mining		30,847		7.5
Oil Services		24,468		6.0
Oil & Gas Producers		9,085		2.2
		64,400		15.7
> Consumer Goods & Services
Other Consumer Services		25,313		6.2
Nondurables		11,947		2.9
Retail		3,839		0.9
Casinos & Gaming		427		0.1
		41,526		10.1
> Other Industries
Real Estate		16,218		4.0
Transportation		12,445		3.0
Regulated Utilities		10,807		2.6
		39,470		9.6
> Finance
Brokerage & Money Management		14,145		3.4
Banks		9,694		2.4
		23,839		5.8

	Value (000)			Percentage of Net Assets
> Health Care
Medical Equipment & Devices	$	10,215			2.5
Health Care Services		4,256			1.0
Pharmaceuticals		3,448			0.8
		17,919			4.3
Total Equities:		383,290			93.3
Exchange Traded Fund:		4,215			1.0
Short-Term Obligations:		23,979			5.9
Total Investments:		411,484			100.2
Cash and Other Assets Less Liabilities:		(809	)		(0.2	)
Net Assets:	$	410,675			100.0

See accompanying notes to financial statements.

58

Columbia Acorn Select

Major Portfolio Changes in the Fourth Quarter (Unaudited)

	Number of Shares
	09/30/09		12/31/09
Purchases
Consumer Goods & Services
Abercrombie & Fitch		750,000		1,650,000
GLG Life Tech (Canada)		0		108,000
ITT Educational Services		825,000		1,000,000
Safeway		3,500,000		3,600,000
Steelcase		2,612,994		3,000,000
Information
Globalstar		11,800,000		13,400,800
VisionChina Media - ADR (China)		4,121,817		4,250,000
WNS - ADR (India)		3,900,000		3,913,900
Energy & Minerals
Alange Energy (Colombia)		156,600		8,400,000
Houston American Energy		0		1,050,000
Cap-Link Ventures		0		17,144,000
Cap-Link Ventures-Warrants		0		17,144,000
Finance
Discover Financial Services		1,350,000		2,050,000
Industrial Goods & Services
Ametek		675,000		750,000

	Number of Shares
	09/30/09		12/31/09
Sales
Consumer Goods & Services
Career Education		1,300,000		977,000
Gap		575,000		0
Hertz		7,750,000		7,500,000
NagaCorp (Hong Kong)		76,000,000		29,633,051
SkillSoft - ADR		9,200,000		9,000,000
Information
American Tower		950,000		900,000
CardTronics		3,430,343		2,620,000
China Mass Media - ADR (China)		2,017,600		1,662,685
Discovery Communications, Series C		1,125,000		400,000
Hackett Group		1,334,442		1,000,000
Novell		8,100,000		7,000,000
Energy & Minerals
FMC Technologies		600,000		0
Synthesis Energy Systems (China)		2,500,000		2,200,000
Tetra Technologies		6,400,000		5,000,000
Uranium One (South Africa)		9,150,000		8,500,000
Finance
Conseco		14,900,000		13,500,000
MF Global		5,800,000		5,500,000
SEI Investments		1,250,000		1,100,000
Industrial Goods & Services
Donaldson		250,000		0
Expeditors International of Washington		850,000		600,000
Mobile Mini		750,000		117,328
Quanta Services		2,300,000		1,950,000

See accompanying notes to financial statements.

59

Columbia Acorn Select

Statement of Investments, December 31, 2009

Number of Shares			Value (000)
				Equities: 92.2%
Consumer Goods & Services 31.8%
		> Educational Services 11.2%
	1,000,000	ITT Educational Services (a)	$	95,960
		Post-secondary Degree Services
	9,000,000	SkillSoft - ADR (a)(b)		94,320
		Web-based Learning Solutions (E-Learning)
	977,000	Career Education (a)		22,774
		Post-secondary Education
	950,000	Princeton Review (a)		3,857
		College Preparation Courses
				216,911
		> Travel 8.0%
	7,500,000	Hertz (a)		89,400
		Largest U.S. Rental Car Operator
	2,600,000	Expedia (a)		66,846
		Online Travel Services Company
				156,246
		> Retail 6.9%
	3,600,000	Safeway		76,644
		Supermarkets
	1,650,000	Abercrombie & Fitch		57,502
		Teen Apparel Retailer
				134,146
		> Apparel 2.6%
	1,400,000	Coach		51,142
		Designer & Retailer of Branded Leather Accessories
				51,142
		> Casinos & Gaming 2.0%
	325,000,000	RexLot Holdings (China)		36,280
		Lottery Equipment Supplier in China
	29,633,051	NagaCorp (Hong Kong)		3,274
		Casino/Entertainment Complex in Cambodia
				39,554
		> Furniture & Textiles 1.0%
	3,000,000	Steelcase		19,080
		Office Furniture
				19,080
		> Food & Beverage 0.1%
	108,000	GLG Life Tech (Canada) (a)		826
		Produce an All-natural Sweetener Extracted from the Stevia Plant
	17,500,000	Fu Ji Food & Catering Services (China) (a)(c)		181
		Food Catering Service Provider in China
				1,007
Consumer Goods & Services: Total				618,086
Information 22.4%
		> Mobile Communications 6.6%
	1,550,000	Crown Castle International (a)		60,512
		Communications Towers
	900,000	American Tower (a)		38,889
		Communications Towers in USA & Latin America

Number of Shares			Value (000)
	505,000	SBA Communications (a)	$	17,251
		Communications Towers
	13,400,800	Globalstar (a)(b)(d)		11,659
		Satellite Mobile Voice & Data Carrier
				128,311
		> Contract Manufacturing 4.7%
	8,200,000	Sanmina-SCI (a)(b)		90,446
		Electronic Manufacturing Services
				90,446
		> Computer Services 3.2%
	3,913,900	WNS - ADR (India) (a)(b)(d)		58,904
		Offshore BPO (Business Process Outsourcing) Services
	1,000,000	Hackett Group (a)		2,780
		IT Integration & Best Practice Research
				61,684
		> Advertising 2.6%
	4,250,000	VisionChina Media - ADR (China) (a)(b)(d)		46,410
		Advertising on Digital Screens in China's Mass Transit System
	1,662,685	China Mass Media - ADR (China) (a)(b)(d)		4,290
		Media Planning Agency in China
				50,700
		> Computer Hardware & Related Equipment 1.8%
	750,000	Amphenol		34,635
		Electronic Connectors
				34,635
		> Business Software 1.5%
	7,000,000	Novell (a)		29,050
		Directory, Operating System & Identity Management Software
				29,050
		> Financial Processors 1.5%
	2,620,000	CardTronics (a)(b)		29,003
		Operates the World's Largest Network of ATMs
				29,003
		> CATV 0.5%
	400,000	Discovery Communications, Series C (a)		10,608
		CATV Programming
				10,608
Information: Total				434,437
Energy & Minerals 15.7%
		> Oil & Gas Producers 8.5%
	4,966,666	Pacific Rubiales Energy (Canada) (a)(e)		73,004
	1,483,334	Pacific Rubiales Energy (Canada) (a)		21,913
		Oil Production & Exploration in Colombia
	32,240,000	Canacol Energy (Canada) (a)(b)(e)		18,835
		Oil Producer in South America

See accompanying notes to financial statements.

60

Number of Shares			Value (000)
		> Oil & Gas Producers—continued
	2,500,000	Gran Tierra Energy (Canada) (a)	$	14,342
		Oil Exploration & Production in Colombia, Peru & Argentina
	17,144,000	Cap-Link Ventures (a)(e)		7,213
	17,144,000	Cap-Link Ventures-Warrants (a)(e)		4,590
		Oil & Gas Exploration & Production in Colombia, Peru & Paraguay
	25,883,000	ShaMaran Petroleum (Canada) (a)(b)(e)		10,691
	5,117,000	ShaMaran Petroleum (Canada) (a)(b)		2,202
		Oil Exploration in Kurdistan
	1,050,000	Houston American Energy		6,468
		Oil & Gas Exploration/Production in Colombia
	8,400,000	Alange Energy (Colombia) (a)		5,060
		Oil & Gas Exploration/Production in Colombia
				164,318
		> Alternative Energy 3.1%
	1,900,000	Canadian Solar (China) (a)(d)		54,758
		Solar Cell & Module Manufacturer
	1,400,000	Real Goods Solar (a)(b)		4,410
		Residential Solar Energy Installer
	2,200,000	Synthesis Energy Systems (China) (a)		2,041
		Owner/Operator of Gasification Plants
				61,209
		> Oil Services 2.8%
	5,000,000	Tetra Technologies (a)(b)		55,400
		U.S.-based Services Company with Life of Field Approach
				55,400
		> Mining 1.3%
	8,500,000	Uranium One (South Africa) (a)		24,545
		Uranium Mines in Kazakhstan, the U.S. & Australia
				24,545
Energy & Minerals: Total				305,472
Finance 10.0%
		> Brokerage & Money Management 5.0%
	1,300,000	Eaton Vance		39,533
		Specialty Mutual Funds
	5,500,000	MF Global (a)		38,225
		Futures Broker
	1,100,000	SEI Investments		19,272
		Mutual Fund Administration & Investment Management
				97,030
		> Insurance 3.5%
	13,500,000	Conseco (a)(b)		67,500
		Life, Long-term Care & Medical Supplement Insurance
				67,500

Number of Shares			Value (000)
		> Credit Cards 1.5%
	2,050,000	Discover Financial Services	$	30,156
		Credit Card Company
				30,156
Finance: Total				194,686
Industrial Goods & Services 9.1%
		> Waste Management 2.6%
	1,500,000	Waste Management		50,715
		U.S. Garbage Collection & Disposal
				50,715
		> Outsourcing Services 2.1%
	1,950,000	Quanta Services (a)		40,638
		Electrical & Telecom Construction Services
				40,638
		> Machinery 1.5%
	750,000	Ametek		28,680
		Aerospace/Industrial Instruments
				28,680
		> Industrial Materials & Specialty Chemicals 1.3%
	1,000,000	Nalco Holding Company		25,510
		Provider of Water Treatment & Process Chemicals & Services
	18,263	ChemSpec International - ADR (China) (a)		120
		Specialty Chemicals with Focus on Fluorinated Chemical Manufacturing
				25,630
		> Other Industrial Services 1.2%
	600,000	Expeditors International of Washington		20,838
		International Freight Forwarder
	117,328	Mobile Mini (a)		1,653
		Portable Storage Units Leasing
				22,491
		> Industrial Distribution 0.4%
	90,000	WW Grainger		8,715
		Industrial Distribution
				8,715
Industrial Goods & Services: Total				176,869
Other Industries 3.2%
		> Transportation 3.2%
	1,300,000	JB Hunt Transport Services		41,951
		Truck & Intermodal Carrier
	1,125,000	American Commercial Lines (a)(b)		20,621
		Operator of Inland Barges/Builder of Barges & Vessels
				62,572
Other Industries: Total				62,572

See accompanying notes to financial statements.

61

Columbia Acorn Select

Statement of Investments, continued

Number of Shares or Principal Amount (000)			Value (000)
Health Care —%
		> Health Care Services —%
	27,500	Emdeon (a)	$	419
		Revenue & Payment Cycle Management
				419
Health Care: Total				419
Total Equities: 92.2% (Cost: $1,551,056)				1,792,541
Securities Lending Collateral: 0.2%
	3,884,667	Dreyfus Government Cash Management Fund (7 day yield of 0.000%) (f)		3,885
Total Securities Lending Collateral: (Cost: $3,885)				3,885
Short-Term Obligations: 8.0%
		> Repurchase Agreement 7.5%
$	146,852	Repurchase Agreement with Fixed Income Clearing Corp., dated 12/31/09, due 1/04/10 at 0.00%, collateralized by a U.S. Treasury obligation, maturing 4/01/10, market value $149,790 (repurchase proceeds $146,852)		146,852
				146,852
		> Commercial Paper 0.5%
	9,300	Toyota Motor Credit 0.16% due 1/04/10		9,300
				9,300
Total Short-Term Obligations: (Amortized Cost: $156,152)				156,152
Total Investments: 100.4% (Cost: $1,711,093)(g)				1,952,578
Obligation to Return Collateral for Securities Loaned: (0.2)%				(3,885	)
Cash and Other Assets Less Liabilities: (0.2)%				(3,848	)
Total Net Assets: 100.0%			$	1,944,845

ADR = American Depositary Receipts.

See accompanying notes to financial statements.

62

> Notes to Statement of Investments (dollar values in thousands)

(a)  Non-income producing security.

(b)  An affiliated person of the Fund may include any company in which the Fund owns five percent or more of its outstanding voting shares. Holdings and transactions in affiliated companies during the twelve months ended December 31, 2009, are as follows:

Affiliates	Balance of Shares Held 12/31/08		Purchases/ Additions		Sales/ Reductions			Balance of Shares Held 12/31/09		Value		Dividend
American Commercial Lines		3,803,849		696,151		3,375,000	**		1,125,000	$	20,621	$	-
Canacol Energy		-		32,240,000		-			32,240,000		18,835
Canadian Solar*		1,825,000		400,000		325,000			1,900,000		54,758		-
CardTronics		3,560,000		140,000		1,080,000			2,620,000		29,003		-
China Mass Media - ADR		2,350,000		-		687,315			1,662,685		4,290		-
Conseco		14,950,000		-		1,450,000			13,500,000		67,500		-
Globalstar		10,000,000		4,600,800		1,200,000			13,400,800		11,659		-
Real Goods Solar		1,500,000		-		100,000			1,400,000		4,410		-
Sanmina-SCI		50,200,000		-		42,000,000	***		8,200,000		90,446		-
ShaMaran Petroleum		-		31,000,000		-			31,000,000		12,893
SkillSoft - ADR		9,500,000		-		500,000			9,000,000		94,320		-
Synthesis Energy Systems*		2,800,000		-		600,000			2,200,000		2,041		-
Tetra Technologies		6,150,000		1,050,000		2,200,000			5,000,000		55,400		-
VisionChina Media - ADR		3,118,900		1,131,100		-			4,250,000		46,410
WNS - ADR		3,100,000		859,975		46,075			3,913,900		58,904		-
Total of Affiliated Transactions		112,857,749		72,118,026		53,563,390			131,412,385	$	571,490	$	-

*  At December 31, 2009, the Fund owned less than five percent of the company's outstanding voting shares.

**  Includes the effect of a 1:4 reverse stock split.

***  Includes the effect of a 1:6 reverse stock split.

  The aggregate cost and value of these companies at December 31, 2009, were $705,100 and $571,490, respectively. Investments in affiliated companies represented 29.4% of total net assets at December 31, 2009.

(c)  Illiquid security.

(d)  All or a portion of this security was on loan at December 31, 2009. The total market value of Fund securities on loan at December 31, 2009 was $3,749.

(e)  Denotes a restricted security, which is subject to restrictions on resale under federal securities laws. These securities are valued at a fair value determined in good faith under consistently applied procedures established by the Board of Trustees. At December 31, 2009, the market value of these securities amounted to $114,333, which represented 5.88% of total net assets.

  Additional information on these securities is as follows:

Security	Acquisition Dates	Shares		Cost		Value
Canacol Energy	9/23/09		32,240,000	$	8,397	$	18,835
Pacific Rubiales Energy	7/12/07		4,966,666		19,942		73,004
Cap-Link Ventures	11/20/09		17,144,000		3,499		7,213
Cap-Link Ventures-Warrants	11/20/09		17,144,000		2,226		4,590
ShaMaran Petroleum	9/15/09		25,883,000		18,117		10,691
				$	52,181	$	114,333

(f)  Investment made with cash collateral received from securities lending activity.

(g)  At December 31, 2009, for federal income tax purposes, the cost of investments was $1,729,836 and net unrealized appreciation was $222,742, consisting of gross unrealized appreciation of $585,007 and gross unrealized depreciation of $362,265.

See accompanying notes to financial statements.

63

Columbia Acorn Select

Statement of Investments, continued

> Notes to Statement of Investments (dollar values in thousands)

  The following table summarizes the inputs used, as of December 31, 2009, in valuing the Fund's assets:

Investment Type	Quoted Prices (Level 1)		Other Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Equities
Consumer Goods & Services	$	578,351	$	39,554	$	181	$	618,086
Information		434,437		-		-		434,437
Energy & Minerals		191,139		114,333		-		305,472
Finance		194,686		-		-		194,686
Industrial Goods & Services		176,869		-		-		176,869
Other Industries		62,572		-		-		62,572
Health Care		419		-		-		419
Total Equities		1,638,473		153,887		181		1,792,541
Total Securities Lending Collateral		3,885		-		-		3,885
Total Short-Term Obligations		-		156,152		-		156,152
Total Investments	$	1,642,358	$	310,039	$	181	$	1,952,578

  The Fund's assets assigned to the Level 2 input category include certain foreign securities for which a third party statistical pricing service may be employed for purposes of fair market valuation.

  The following table reconciles asset balances for the twelve-month period ending December 31, 2009, in which significant unobservable inputs (Level 3) were used in determining value:

Investments in Securities	Balance as of December 31, 2008		Accrued Discounts/ Premiums		Realized Gain/(Loss)		Change in Unrealized Appreciation (Depreciation)			Net Purchases (Sales)		Net Transfers into (out of) Level 3		Balance as of December 31, 2009
Equities
Consumer Goods & Services	$	-	$	-	$	-	$	(14,925	)	$	-	$	15,106	$	181
	$	-	$	-	$	-	$	(14,925	)	$	-	$	15,106	$	181

  The information in the above reconciliation table represents fiscal year to date activity for any securities identified as using Level 3 inputs during the current fiscal period.

  The change in unrealized appreciation (depreciation) attributed to securities owned at December 31, 2009, which were valued using significant unobservable inputs (Level 3) amounted to $(14,925). This amount is included in net change in unrealized depreciation on the Statements of Changes in Net Assets.

  For more information on valuation inputs, and their aggregation into the levels used in the tables above, please refer to the Security Valuation section in the accompanying Notes to Financial Statements.

See accompanying notes to financial statements.

64

Columbia Thermostat Fund

Statement of Investments, December 31, 2009

Number of Shares or Principal Amount (000)			Value (000)
		> Stock Funds: 85.0%
	2,728,249	Columbia Large Cap Enhanced Core Fund, Class Z	$	29,383
	1,982,660	Columbia Dividend Income Fund, Class Z		23,495
	720,997	Columbia Acorn Fund, Class Z		17,794
	1,018,204	Columbia Marsico Growth Fund, Class Z		17,605
	513,283	Columbia Acorn International, Class Z		17,585
	510,373	Columbia Acorn Select, Class Z		11,932
Total Stock Funds (Cost: $119,130)				117,794
		> Bond Funds: 14.5%
	1,148,436	Columbia Intermediate Bond Fund, Class Z		10,095
	535,341	Columbia U.S. Treasury Index Fund, Class Z		5,932
	551,500	Columbia Conservative High Yield Fund, Class Z		4,125
Total Bond Funds (Cost: $19,764)				20,152
Short-Term Obligation: 0.6%
		> Repurchase Agreement: 0.6%
$	787	Repurchase Agreement with Fixed Income Clearing Corp., dated 12/31/09, due 1/04/10 at 0.00%, collateralized by a U.S. Government Agency obligation, maturing 9/17/10, market value $806 (repurchase proceeds $787)		787
Total Short-Term Obligation (Cost: $787)				787
Total Investments: 100.1% (Cost: $139,681)(a)				138,733
Cash and Other Assets Less Liabilities: (0.1)%				(144	)
Total Net Assets: 100.0%			$	138,589

See accompanying notes to financial statements.

65

Columbia Thermostat Fund

Statement of Investments, continued

> Notes to Statement of Investments (dollar values in thousands)

(a)  At December 31, 2009, for federal income tax purposes, the cost of investments was $140,157 and net unrealized depreciation was $1,424, consisting of gross unrealized appreciation of $8,876 and gross unrealized depreciation of $10,300.

  The following table summarizes the inputs used, as of December 31, 2009, in valuing the Fund's assets:

Investment Type	Quoted Prices (Level 1)		Other Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Total Stock Funds	$	117,794	$	-	$	-	$	117,794
Total Bond Funds		20,152		-		-		20,152
Total Short-Term Obligation		-		787		-		787
Total Investments	$	137,946	$	787	$	-	$	138,733

  For more information on valuation inputs, and their aggregation into the levels used in the table above, please refer to the Security Valuation section in the accompanying Notes to Financial Statements.

See accompanying notes to financial statements.

66

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67

Columbia Acorn Family of Funds

Statements of Assets and Liabilities

December 31, 2009	Columbia Acorn Fund			Columbia Acorn International			Columbia Acorn USA			Columbia Acorn International Select			Columbia Acorn Select			Columbia Thermostat Fund
(in thousands)
Assets:
Unaffiliated investments, at cost	$	7,848,115		$	3,281,798		$	1,111,049		$	329,798		$	1,005,993		$	787
Affiliated investments, at cost (See Note 4)		3,167,879			77,410			16,520			—			705,100			138,894
Unaffiliated investments, at value (including securities on loan: Columbia Acorn Fund $175,896; Columbia Acorn International $25,743; Columbia Acorn USA $16,200; Columbia Acorn International Select $–; Columbia Acorn Select $3,749; Columbia Thermostat Fund $–)	$	11,210,831		$	4,300,923		$	1,398,951		$	411,484		$	1,381,088		$	787
Affiliated investments, at value (See Note 4)		3,750,852			114,524			13,727			—			571,490			137,946
Cash		34			—			—	*		—			—			1
Foreign currency (cost: Columbia Acorn Fund $3,308; Columbia Acorn International $29,329; Columbia Acorn International Select $25; Columbia Acorn Select $113)		3,453			29,594			—			25			113			—
Net unrealized appreciation on forward foreign currency exchange contracts		—			6,689			—			—			—			—
Receivable for:
Investments sold		19,206			8,744			6,072			5			178			273
Fund shares sold		14,294			8,161			604			769			2,479			93
Dividends and interest		7,667			4,939			649			368			892			—
Securities lending income		89			27			10			—			4			—
Foreign tax reclaims		166			1,030			—			16			—			—
Trustees' Deferred Compensation Investments		3,145			876			244			—			288			—
Other assets		92			25			8			3			11			1
Total Assets		15,009,829			4,475,532			1,420,265			412,670			1,956,543			139,101
Liabilities:
Payable to custodian bank		—			9			—			—	*		4			—
Collateral on securities loaned		183,434			26,644			16,749			—			3,885			—
Expense reimbursement due to Advisor		—			—			—			—	*		—			6
Net unrealized depreciation on forward foreign currency exchange contracts		—			4,205			—			—			—			—
Payable for:
Investments purchased		44,749			4,766			1,144			189			48			—
Fund shares redeemed		37,841			2,725			11,007			1,259			5,221			327
Management fee		7,895			2,855			999			327			1,321			12
Administration fee		502			152			47			14			66			5
12b-1 Service & Distribution fees		1,567			217			78			25			242			48
Reports to shareholders		785			327			108			46			191			41
Deferred Trustees' fees		3,145			876			244			44			288			28
Transfer agent fees		2,095			405			230			37			329			30
Trustees' fees		—	*		—	*		2			—	*		—	*		—	*
Custody fees		181			289			5			22			50			—
Chief compliance officer expenses		27			8			2			1			4			—	*
Foreign capital gains tax		200			1,217			—			—			—			—
Other liabilities		257			99			41			31			49			15
Total Liabilities		282,678			44,794			30,656			1,995			11,698			512
Net Assets	$	14,727,151		$	4,430,738		$	1,389,609		$	410,675		$	1,944,845		$	138,589
Composition of Net Assets:
Paid in capital	$	11,247,302		$	3,962,215		$	1,228,860		$	405,974		$	1,850,202		$	166,320
Undistributed/(overdistributed) net investment income (Accumulated net investment loss)		(20,794	)		39,113			(275	)		1,978			(8,359	)		1,247
Accumulated net realized gain/(loss)		(444,982	)		(628,257	)		(124,085	)		(78,954	)		(138,483	)		(28,030	)
Net unrealized appreciation/(depreciation) on:
Investments		3,945,689			1,056,239			285,109			81,686			241,485			(948	)
Foreign capital gains tax		(200	)		(1,217	)		—			—			—			—
Foreign currency translations		136			2,645			—			(9	)		—	*		—
Net Assets	$	14,727,151		$	4,430,738		$	1,389,609		$	410,675		$	1,944,845		$	138,589
Net asset value per share – Class A (a)	$	23.98		$	34.13		$	22.43		$	23.39		$	22.81		$	10.90
(Net assets/shares)		($2,937,761/122,497)			($578,599/16,955)			($178,605/7,962)			($64,664/2,764)			($522,443/22,908)			($42,976/3,943)
Maximum offering price per share – Class A (b)	$	25.44		$	36.21		$	23.80		$	24.82		$	24.20		$	11.56
(Net asset value per share/front- end sales charge)		($23.98/0.9425)			($34.13/0.9425)			($22.43/0.9425)			($23.39/0.9425)			($22.81/0.9425)			($10.90/0.9425)
Net asset value and offering price per share – Class B (a)	$	22.43		$	33.22		$	20.99		$	22.34		$	21.41		$	10.93
(Net assets/shares)		($525,072/23,411)			($38,835/1,169)			($20,903/996)			($3,887/174)			($88,004/4,111)			($32,758/2,997)
Net asset value and offering price per share – Class C (a)	$	22.23		$	33.08		$	20.84		$	22.21		$	21.25		$	10.91
(Net assets/shares)		($736,818/33,142)			($85,625/2,588)			($32,508/1,560)			($11,096/500)			($93,121/4,382)			($21,090/1,933)
Net asset value and offering price per share – Class Z (c)	$	24.68		$	34.26		$	23.19		$	23.64		$	23.38		$	10.80
(Net assets/shares)		($10,527,500/426,515)			($3,727,679/108,818)			($1,157,593/49,909)			($331,028/14,003)			($1,241,277/53,093)			($41,765/3,866)

(a)  Redemption price per share is equal to net asset value less any applicable contingent deferred sales charge and redemption fee.

(b)  On sales of $50,000 or more the offering price is reduced.

(c)  Redemption price per share is equal to net asset value less any applicable redemption fee.

*  Rounds to less than $500.

See accompanying notes to financial statements.

68

Columbia Acorn Family of Funds

Statements of Operations
For the Year Ended December 31, 2009

(in thousands)	Columbia Acorn Fund			Columbia Acorn International			Columbia Acorn USA			Columbia Acorn International Select			Columbia Acorn Select			Columbia Thermostat Fund
Investment Income:
Dividend income	$	97,974		$	78,907		$	7,290		$	7,141		$	7,661		$	—
Dividend income from affiliates (See Note 4)		17,346			3,000			—			—			—			—
Dividends from affiliated investment company shares (See Note 4)		—			—			—			—			—			2,149
Interest income		459			149			23			16			68			—	*
Securitites lending income		957			174			139			1			282			—
		116,736			82,230			7,452			7,158			8,011			2,149
Foreign taxes withheld		(1,865	)		(6,487	)		(5	)		(521	)		—			—
Total Investment Income		114,871			75,743			7,447			6,637			8,011			2,149
Expenses:
Management fee		77,909			26,444			9,677			3,039			12,761			128
Administration fee		5,179			1,459			477			138			666			55
12b-1 Service and Distribution fees:
Class A		6,042			1,076			372			137			1,086			99
Class B		3,969			279			162			29			581			245
Class C		6,373			676			269			98			769			204
Transfer agent fees:
Class A		1,927			681			135			81			434			77
Class B		1,309			122			62			15			241			77
Class C		950			149			39			25			147			44
Class Z		2,857			1,241			446			87			446			17
Custody fees		921			2,572			51			213			297			—
Trustees' fees		922			260			85			34			119			17
Reports to shareholders		2,065			909			328			167			478			121
Chief compliance officer expenses (See Note 4)		525			142			48			13			66			5
Other expenses		1,431			504			223			168			292			106
Total expenses		112,379			36,514			12,374			4,244			18,383			1,195
Less custody fees paid indirectly		—	*		—	*		—	*		—	*		—	*		—	*
Less reimbursement of expenses by Investment Advisor		—			—			—			(5	)		—			(327	)
Net Expenses		112,379			36,514			12,374			4,239			18,383			868
Net Investment Income/(Loss)		2,492			39,229			(4,927	)		2,398			(10,372	)		1,281
Net Realized and Unrealized Gain (Loss) on Portfolio Positions:
Net realized gain/(loss) on:
Unaffiliated investments		(227,130	)		(248,697	)		(20,041	)		(31,361	)		31,100			—
Affiliated investments (See Note 4)		(100,539	)		(3,829	)		(110	)		—			(71,935	)		(18,232	)
Foreign currency transactions and forward foreign currency   exchange contracts		(229	)		4,140			—			(46	)		589			—
Foreign capital gains tax		—			(1,789	)		—			—			—			—
Distributions from affiliated investment company shares		—			—			—			—			—			1
Net realized loss		(327,898	)		(250,175	)		(20,151	)		(31,407	)		(40,246	)		(18,231	)
Net change in net unrealized appreciation/(depreciation) on:
Unaffiliated investments		3,343,556			1,554,069			437,114			127,658			521,773			—
Affiliated investments (See Note 4)		1,143,521			49,345			1,994			—			316,510			51,494
Foreign currency translations and forward foreign currency   exchange contracts		134			6,043			—			(25	)		(3	)		—
Foreign capital gains tax		(200	)		(1,217	)		—			—			—			—
Net change in unrealized appreciation/ (depreciation)		4,487,011			1,608,240			439,108			127,633			838,280			51,494
Net realized and unrealized gain		4,159,113			1,358,065			418,957			96,226			798,034			33,263
Net Increase in Net Assets resulting from Operations	$	4,161,605		$	1,397,294		$	414,030		$	98,624		$	787,662		$	34,544

*  Rounds to less than $500.

See accompanying notes to financial statements.

69

Columbia Acorn Family of Funds

Statements of Changes in Net Assets

	Columbia Acorn Fund						Columbia Acorn International						Columbia Acorn USA
Increase (Decrease) in Net Assets	Year ended December 31,						Year ended December 31,						Year ended December 31,
(in thousands)	2009			2008 (a)			2009			2008 (a)			2009			2008 (a)
Operations:
Net investment income/(loss)	$	2,492		$	12,367		$	39,229		$	76,400		$	(4,927	)	$	(5,465	)
Net realized gain/(loss) on investments, foreign currency transactions, forward foreign currency exchange contracts and foreign capital gains tax		(227,359	)		234,120			(246,346	)		(283,342	)		(20,041	)		(102,173	)
Net realized gain/(loss) on affiliated investments and distributions from affiliated investment companies and affiliated investment company shares		(100,539	)		(245,832	)		(3,829	)		(95,523	)		(110	)		—
Net change in net unrealized appreciation/(depreciation) on investments, foreign currency translations, forward foreign currency exchange contracts and foreign capital gains tax		3,343,490			(5,424,645	)		1,558,895			(2,403,427	)		437,114			(492,195	)
Net change in net unrealized appreciation/(depreciation) on affiliated investment companies and affiliated investment company shares		1,143,521			(1,918,721	)		49,345			337			1,994			(3,773	)
Net Increase/(Decrease) from Operations		4,161,605			(7,342,711	)		1,397,294			(2,705,555	)		414,030			(603,606	)
Distributions to Shareholders From:
Net investment income – Class A		—			—			(6,102	)		(1,020	)		—			—
Net realized gain – Class A		—			(91,100	)		—			(9,807	)		—			(8,248	)
Net investment income – Class B		—			—			(290	)		—	*		—			—
Net realized gain – Class B		—			(26,893	)		—			(1,332	)		—			(1,748	)
Net investment income – Class C		—			—			(348	)		—	*		—			—
Net realized gain – Class C		—			(28,315	)		—			(2,146	)		—			(1,740	)
Net investment income – Class Z		(20,981	)		(6,088	)		(53,467	)		(23,593	)		—			—
Net realized gain – Class Z		—			(284,695	)		—			(68,973	)		—			(41,787	)
Total Distributions to Shareholders		(20,981	)		(437,091	)		(60,207	)		(106,871	)		—			(53,523	)
Share Transactions:
Subscriptions – Class A		639,685			612,669			181,444			277,346			54,531			53,928
Distributions reinvested – Class A		—			83,711			5,737			9,979			—			7,538
Redemptions – Class A		(744,769	)		(1,151,023	)		(140,626	)		(207,715	)		(66,724	)		(69,749	)
Net Increase/(Decrease) – Class A		(105,084	)		(454,643	)		46,555			79,610			(12,193	)		(8,283	)
Subscriptions – Class B		100			1,991			14			1,704			5			71
Distributions reinvested – Class B		—			24,675			264			1,209			—			1,615
Redemptions – Class B		(224,032	)		(255,304	)		(14,833	)		(23,974	)		(9,892	)		(11,765	)
Net Decrease – Class B		(223,932	)		(228,638	)		(14,555	)		(21,061	)		(9,887	)		(10,079	)
Subscriptions – Class C		58,069			62,517			14,494			20,234			2,513			3,931
Distributions reinvested – Class C		—			22,379			265			1,596			—			1,523
Redemptions – Class C		(151,419	)		(287,537	)		(18,021	)		(43,103	)		(5,210	)		(10,090	)
Net Increase/(Decrease) – Class C		(93,350	)		(202,641	)		(3,262	)		(21,273	)		(2,697	)		(4,636	)
Subscriptions – Class Z		1,484,719			1,526,416			671,256			664,727			246,578			213,395
Distributions reinvested – Class Z		17,690			251,789			38,426			64,910			—			37,687
Redemptions – Class Z		(1,364,770	)		(2,162,613	)		(486,805	)		(912,602	)		(190,623	)		(190,501	)
Net Increase/(Decrease) – Class Z		137,639			(384,408	)		222,877			(182,965	)		55,955			60,581
Net Increase/(Decrease) from Share Transactions		(284,727	)		(1,270,330	)		251,615			(145,689	)		31,178			37,583
Redemption Fees		—			—			259			354			—			—
Increase from regulatory settlements (See Note 9)		40			—			1,210			—			5			—
Total Increase/(Decrease) in Net Assets		3,855,937			(9,050,132	)		1,590,171			(2,957,761	)		445,213			(619,546	)
Net Assets:
Beginning of period		10,871,214			19,921,346			2,840,567			5,798,328			944,396			1,563,942
End of period	$	14,727,151		$	10,871,214		$	4,430,738		$	2,840,567		$	1,389,609		$	944,396
Undistributed/(Overdistributed) Net Investment Income or (Accumulated Net Investment Loss)	$	(20,794	)	$	(2,116	)	$	39,113		$	57,491		$	(275	)	$	(157	)

(a)  Certain items in the prior year financial statements were reclassified to conform to the current year's presentation. Such reclassifications had no effect on net income or net assets.

*  Rounds to less than $500.

See accompanying notes to financial statements.

70

	Columbia Acorn International Select						Columbia Acorn Select						Columbia Thermostat Fund
Increase (Decrease) in Net Assets	Year ended December 31,						Year ended December 31,						Year ended December 31,
(in thousands)	2009			2008			2009			2008 (a)			2009			2008
Operations:
Net investment income/(loss)	$	2,398		$	2,451		$	(10,372	)	$	(17,307	)	$	1,281		$	3,146
Net realized gain/(loss) on investments, foreign currency transactions, forward foreign currency exchange contracts and foreign capital gains tax		(31,407	)		(46,780	)		31,689			(71,830	)		—			—
Net realized gain/(loss) on affiliated investments and distributions from affiliated investment companies and affiliated investment company shares		—			—			(71,935	)		(15,794	)		(18,231	)		(9,015	)
Net change in net unrealized appreciation/(depreciation) on investments, foreign currency translations, forward foreign currency exchange contracts and foreign capital gains tax		127,633			(101,043	)		521,770			(965,213	)		—			—
Net change in net unrealized appreciation/(depreciation) on affiliated investment companies and affiliated investment company shares		—			—			316,510			(365,076	)		51,494			(58,979	)
Net Increase/(Decrease) from Operations		98,624			(145,372	)		787,662			(1,435,220	)		34,544			(64,848	)
Distributions to Shareholders From:
Net investment income – Class A		(456	)		—			—			—			(7	)		(1,051	)
Net realized gain – Class A		—			(984	)		—			(25,410	)		—			(337	)
Net investment income – Class B		—			—			—			—			—			(657	)
Net realized gain – Class B		—			(189	)		—			(4,641	)		—			(371	)
Net investment income – Class C		—			—			—			—			—			(361	)
Net realized gain – Class C		—			(288	)		—			(4,551	)		—			(201	)
Net investment income – Class Z		(3,077	)		(280	)		—			—			(115	)		(1,140	)
Net realized gain – Class Z		—			(3,600	)		—			(39,523	)		—			(301	)
Total Distributions to Shareholders		(3,533	)		(5,341	)		—			(74,125	)		(122	)		(4,419	)
Share Transactions:
Subscriptions – Class A		30,670			47,637			98,691			131,376			5,619			21,460
Distributions reinvested – Class A		439			901			—			23,381			6			1,269
Redemptions – Class A		(28,558	)		(21,936	)		(190,444	)		(377,780	)		(14,381	)		(14,939	)
Net Increase/(Decrease) – Class A		2,551			26,602			(91,753	)		(223,023	)		(8,756	)		7,790
Subscriptions – Class B		—			271			39			388			—			2,089
Distributions reinvested – Class B		—			170			—			4,147			—			943
Redemptions – Class B		(1,493	)		(3,345	)		(23,638	)		(41,288	)		(12,541	)		(14,056	)
Net Decrease – Class B		(1,493	)		(2,904	)		(23,599	)		(36,753	)		(12,541	)		(11,024	)
Subscriptions – Class C		1,872			7,847			6,147			8,177			1,960			17,881
Distributions reinvested – Class C		—			248			—			3,639			—			510
Redemptions – Class C		(3,109	)		(4,044	)		(21,888	)		(51,407	)		(10,176	)		(8,717	)
Net Increase/(Decrease) – Class C		(1,237	)		4,051			(15,741	)		(39,591	)		(8,216	)		9,674
Subscriptions – Class Z		127,520			175,091			278,829			387,091			2,684			23,041
Distributions reinvested – Class Z		833			1,768			—			29,748			106			1,339
Redemptions – Class Z		(59,794	)		(84,177	)		(310,353	)		(373,486	)		(6,183	)		(8,008	)
Net Increase/(Decrease) – Class Z		68,559			92,682			(31,524	)		43,353			(3,393	)		16,372
Net Increase/(Decrease) from Share Transactions		68,380			120,431			(162,617	)		(256,014	)		(32,906	)		22,812
Redemption Fees		33			171			—			—			—			—
Increase from regulatory settlements (See Note 9)		265			—			—			—			—			—
Total Increase/(Decrease) in Net Assets		163,769			(30,111	)		625,045			(1,765,359	)		1,516			(46,455	)
Net Assets:
Beginning of period		246,906			277,017			1,319,800			3,085,159			137,073			183,528
End of period	$	410,675		$	246,906		$	1,944,845		$	1,319,800		$	138,589		$	137,073
Undistributed/(Overdistributed) Net Investment Income or (Accumulated Net Investment Loss)	$	1,978		$	2,875		$	(8,359	)	$	(180	)	$	1,247		$	88

See accompanying notes to financial statements.

71

Columbia Acorn Family of Funds

Statements of Changes in Net Assets, continued

	Columbia Acorn Fund						Columbia Acorn International						Columbia Acorn USA
Changes in Shares of Beneficial Interest:	Year ended December 31,						Year ended December 31,						Year ended December 31,
(in thousands)	2009			2008			2009			2008			2009			2008
Subscriptions – Class A		33,142			26,521			6,366			8,030			3,208			2,597
Shares issued in reinvestment and capital gains – Class A		—			3,428			208			248			—			302
Less shares redeemed – Class A		(39,655	)		(49,918	)		(5,549	)		(6,693	)		(3,839	)		(3,306	)
Net Increase/(Decrease) – Class A		(6,513	)		(19,969	)		1,025			1,585			(631	)		(407	)
Subscriptions – Class B		5			80			—	*		44			—	*		3
Shares issued in reinvestment and capital gains – Class B		—			1,065			10			30			—			68
Less shares redeemed – Class B		(12,472	)		(11,645	)		(588	)		(768	)		(582	)		(573	)
Net Decrease – Class B		(12,467	)		(10,500	)		(578	)		(694	)		(582	)		(502	)
Subscriptions – Class C		3,215			3,082			497			569			148			219
Shares issued in reinvestment and capital gains – Class C		—			975			10			41			—			65
Less shares redeemed – Class C		(8,764	)		(13,528	)		(740	)		(1,414	)		(327	)		(514	)
Net Increase/(Decrease) – Class C		(5,549	)		(9,471	)		(233	)		(804	)		(179	)		(230	)
Subscriptions – Class Z		75,517			63,561			23,146			19,040			14,152			9,874
Shares issued in reinvestment and capital gains – Class Z		750			10,170			1,391			1,609			—			1,466
Less shares redeemed – Class Z		(70,272	)		(93,561	)		(18,261	)		(30,912	)		(10,509	)		(8,493	)
Net Increase/(Decrease) – Class Z		5,995			(19,830	)		6,276			(10,263	)		3,643			2,847
Net Increase/(Decrease) in Shares of Beneficial Interest		(18,534	)		(59,770	)		6,490			(10,176	)		2,251			1,708

*  Rounds to less than 500.

See accompanying notes to financial statements.

72

	Columbia Acorn International Select						Columbia Acorn Select						Columbia Thermostat Fund
Changes in Shares of Beneficial Interest:	Year ended December 31,						Year ended December 31,						Year ended December 31,
(in thousands)	2009			2008			2009			2008			2009			2008
Subscriptions – Class A		1,653			1,986			5,917			6,192			646			1,952
Shares issued in reinvestment and capital gains – Class A		22			30			—			901			1			147
Less shares redeemed – Class A		(1,497	)		(959	)		(11,758	)		(18,425	)		(1,674	)		(1,454	)
Net Increase/(Decrease) – Class A		178			1,057			(5,841	)		(11,332	)		(1,027	)		645
Subscriptions – Class B		—			10			2			16			—			176
Shares issued in reinvestment and capital gains – Class B		—			6			—			168			—			104
Less shares redeemed – Class B		(85	)		(149	)		(1,512	)		(2,059	)		(1,410	)		(1,344	)
Net Decrease – Class B		(85	)		(133	)		(1,510	)		(1,875	)		(1,410	)		(1,064	)
Subscriptions – Class C		103			317			371			469			212			1,558
Shares issued in reinvestment and capital gains – Class C		—			9			—			148			—			56
Less shares redeemed – Class C		(174	)		(183	)		(1,474	)		(2,581	)		(1,207	)		(861	)
Net Increase/(Decrease) – Class C		(71	)		143			(1,103	)		(1,964	)		(995	)		753
Subscriptions – Class Z		6,808			7,667			15,845			17,670			307			1,994
Shares issued in reinvestment and capital gains – Class Z		42			58			—			1,123			12			153
Less shares redeemed – Class Z		(3,083	)		(3,845	)		(18,178	)		(18,669	)		(727	)		(783	)
Net Increase/(Decrease) – Class Z		3,767			3,880			(2,333	)		124			(408	)		1,364
Net Increase/(Decrease) in Shares of Beneficial Interest		3,789			4,947			(10,787	)		(15,047	)		(3,840	)		1,698

See accompanying notes to financial statements.

73

Columbia Acorn Family of Funds

Financial Highlights

Columbia Acorn Fund

Class A Shares	Year Ended December 31,
Selected data for a share outstanding throughout each period	2009			2008			2007			2006			2005
Net Asset Value, Beginning of Period	$	17.22		$	28.87		$	29.02		$	27.57		$	25.93
Income from Investment Operations
Net investment income/(loss) (a)		(0.02	)		(0.01	)		0.05	(b)		0.05			0.07
Net realized and unrealized gain/(loss)		6.78			(10.98	)		2.13			3.82			3.20
Total from Investment Operations		6.76			(10.99	)		2.18			3.87			3.27
Less Distributions to Shareholders
From net investment income		—			—			(0.03	)		(0.04	)		(0.07	)
From net realized gains		—			(0.66	)		(2.30	)		(2.38	)		(1.56	)
Total Distributions to Shareholders		—			(0.66	)		(2.33	)		(2.42	)		(1.63	)
Increase from regulatory settlements		—	(c)		—			—			—			—
Net Asset Value, End of Period	$	23.98		$	17.22		$	28.87		$	29.02		$	27.57
Total Return (d)		39.26	%		(38.72	)%		7.39	%(e)(f)		14.13	%(e)		12.76	%(e)
Ratios to Average Net Assets/Supplemental Data
Net expenses (g)		1.07	%		1.05	%		1.02	%		1.02	%		1.03	%
Net investment income/(loss) (g)		(0.12	)%		(0.04	)%		0.17	%		0.17	%		0.28	%
Waiver/Reimbursement		—			—			0.01	%		0.02	%		0.02	%
Portfolio turnover rate		27	%		21	%		20	%		22	%		16	%
Net assets at end of period (000s)	$	2,937,761		$	2,221,100		$	4,300,920		$	4,067,868		$	3,349,461

(a)  Per share data was calculated using the average shares outstanding during the period.

(b)  Net investment income per share includes special dividends. The effect of these dividends amounted to $0.03 per share.

(c)  Rounds to less than $0.01 per share.

(d)  Total return at net asset value assuming all distributions reinvested and no initial sales charge or contingent deferred sales charge.

(e)  Had the Advisor and/or Transfer Agent not waived fees and/or reimbursed a portion of expenses, total return would have been reduced.

(f)  Total return includes a voluntary reimbursement by the Advisor for a realized investment loss due to a trading error. This reimbursement increased total return and net asset value per share by less than 0.01% and less than $0.01, respectively.

(g)  The benefits derived from custody fees paid indirectly had an impact of less than 0.01%.

Class B Shares	Year Ended December 31,
Selected data for a share outstanding throughout each period	2009			2008			2007			2006			2005
Net Asset Value, Beginning of Period	$	16.21		$	27.39		$	27.78		$	26.61		$	25.19
Income from Investment Operations
Net investment loss (a)		(0.14	)		(0.15	)		(0.11	)(b)		(0.13	)		(0.11	)
Net realized and unrealized gain/(loss)		6.36			(10.37	)		2.02			3.68			3.09
Total from Investment Operations		6.22			(10.52	)		1.91			3.55			2.98
Less Distributions to Shareholders
From net realized gains		—			(0.66	)		(2.30	)		(2.38	)		(1.56	)
Total Distributions to Shareholders		—			(0.66	)		(2.30	)		(2.38	)		(1.56	)
Increase from regulatory settlements		—	(c)		—			—			—			—
Net Asset Value, End of Period	$	22.43		$	16.21		$	27.39		$	27.78		$	26.61
Total Return (d)		38.37	%		(39.11	)%		6.76	%(e)(f)		13.43	%(e)		11.98	%(e)
Ratios to Average Net Assets/Supplemental Data
Net expenses (g)		1.74	%		1.65	%		1.59	%		1.66	%		1.72	%
Net investment loss (g)		(0.77	)%		(0.64	)%		(0.39	)%		(0.48	)%		(0.42	)%
Waiver/Reimbursement		—			—			0.01	%		0.02	%		0.02	%
Portfolio turnover rate		27	%		21	%		20	%		22	%		16	%
Net assets at end of period (000s)	$	525,072		$	581,587		$	1,270,292		$	1,404,165		$	1,422,580

(a)  Per share data was calculated using the average shares outstanding during the period.

(b)  Net investment income per share includes special dividends. The effect of these dividends amounted to $0.03 per share.

(c)  Rounds to less than $0.01 per share.

(d)  Total return at net asset value assuming all distributions reinvested and no contingent deferred sales charge.

(e)  Had the Advisor and/or Transfer Agent not waived fees and/or reimbursed a portion of expenses, total return would have been reduced.

(f)  Total return includes a voluntary reimbursement by the Advisor for a realized investment loss due to a trading error. This reimbursement increased total return and net asset value per share by less than 0.01% and less than $0.01, respectively.

(g)  The benefits derived from custody fees paid indirectly had an impact of less than 0.01%.

Class C Shares	Year Ended December 31,
Selected data for a share outstanding throughout each period	2009			2008			2007			2006			2005
Net Asset Value, Beginning of Period	$	16.09		$	27.25		$	27.70		$	26.58		$	25.18
Income from Investment Operations
Net investment loss (a)		(0.17	)		(0.19	)		(0.18	)(b)		(0.17	)		(0.13	)
Net realized and unrealized gain/(loss)		6.31			(10.31	)		2.03			3.67			3.09
Total from Investment Operations		6.14			(10.50	)		1.85			3.50			2.96
Less Distributions to Shareholders
From net realized gains		—			(0.66	)		(2.30	)		(2.38	)		(1.56	)
Total Distributions to Shareholders		—			(0.66	)		(2.30	)		(2.38	)		(1.56	)
Increase from regulatory settlements		—	(c)		—			—			—			—
Net Asset Value, End of Period	$	22.23		$	16.09		$	27.25		$	27.70		$	26.58
Total Return (d)		38.16	%		(39.23	)%		6.56	%(e)(f)		13.25	%(e)		11.90	%(e)
Ratios to Average Net Assets/Supplemental Data
Net expenses (g)		1.89	%		1.83	%		1.79	%		1.80	%		1.82	%
Net investment loss (g)		(0.93	)%		(0.82	)%		(0.60	)%		(0.61	)%		(0.51	)%
Waiver/Reimbursement		—			—			0.00	%(h)		0.02	%		0.02	%
Portfolio turnover rate		27	%		21	%		20	%		22	%		16	%
Net assets at end of period (000s)	$	736,818		$	622,665		$	1,312,243		$	1,345,520		$	1,220,339

(a)  Per share data was calculated using the average shares outstanding during the period.

(b)  Net investment income per share includes special dividends. The effect of these dividends amounted to $0.03 per share.

(c)  Rounds to less than $0.01 per share.

(d)  Total return at net asset value assuming all distributions reinvested and no contingent deferred sales charge.

(e)  Had the Advisor and/or Transfer Agent not waived fees and/or reimbursed a portion of expenses, total return would have been reduced.

(f)  Total return includes a voluntary reimbursement by the Advisor for a realized investment loss due to a trading error. This reimbursement increased total return and net asset value per share by less than 0.01% and less than $0.01, respectively.

(g)  The benefits derived from custody fees paid indirectly had an impact of less than 0.01%.

(h)  Rounds to less than 0.01%.

See accompanying notes to financial statements.

74

Columbia Acorn International

Class A Shares	Year Ended December 31,
Selected data for a share outstanding throughout each period	2009			2008			2007			2006			2005
Net Asset Value, Beginning of Period	$	23.03		$	43.42		$	40.07		$	33.20		$	28.75
Income from Investment Operations
Net investment income (a)		0.23			0.47			0.27			0.23			0.22
Net realized and unrealized gain/(loss)		11.27			(20.20	)		6.52			10.87			5.84
Total from Investment Operations		11.50			(19.73	)		6.79			11.10			6.06
Less Distributions to Shareholders
From net investment income		(0.41	)		(0.06	)		(0.08	)		(0.32	)		(0.53	)
From net realized gains		—			(0.60	)		(3.36	)		(3.91	)		(1.08	)
Total Distributions to Shareholders		(0.41	)		(0.66	)		(3.44	)		(4.23	)		(1.61	)
Redemption Fees
Redemption fees added to paid in capital (a)(b)		0.00			0.00			0.00			0.00			0.00
Increase from regulatory settlements		0.01			—			—			—			—
Net Asset Value, End of Period	$	34.13		$	23.03		$	43.42		$	40.07		$	33.20
Total Return (c)		50.40	%		(46.09	)%		16.90	%(d)		34.16	%(d)		21.42	%(d)
Ratios to Average Net Assets/Supplemental Data
Net expenses (e)		1.36	%		1.31	%		1.23	%		1.24	%		1.30	%
Net investment income (e)		0.85	%		1.36	%		0.60	%		0.61	%		0.72	%
Waiver/Reimbursement		—			—			0.00	%(f)		0.01	%		0.02	%
Portfolio turnover rate		31	%		38	%		28	%		31	%		27	%
Net assets at end of period (000s)	$	578,599		$	366,820		$	622,901		$	313,401		$	142,204

(a)  Per share data was calculated using the average shares outstanding during the period.

(b)  Rounds to less than $0.01 per share.

(c)  Total return at net asset value assuming all distributions reinvested and no initial sales charge or contingent deferred sales charge.

(d)  Had the Advisor and/or Transfer Agent not waived fees and/or reimbursed a portion of expenses, total return would have been reduced.

(e)  The benefits derived from custody fees paid indirectly had an impact of less than 0.01%.

(f)  Rounds to less than 0.01%.

Class B Shares	Year Ended December 31,
Selected data for a share outstanding throughout each period	2009			2008			2007			2006			2005
Net Asset Value, Beginning of Period	$	22.41		$	42.46		$	39.39		$	32.71		$	28.18
Income from Investment Operations
Net investment income/(loss) (a)		0.08			0.27			0.04			(0.00	)(b)		0.02
Net realized and unrealized gain/(loss)		10.92			(19.72	)		6.39			10.66			5.73
Total from Investment Operations		11.00			(19.45	)		6.43			10.66			5.75
Less Distributions to Shareholders
From net investment income		(0.20	)		—			(0.00	)(b)		(0.07	)		(0.14	)
From net realized gains		—			(0.60	)		(3.36	)		(3.91	)		(1.08	)
Total Distributions to Shareholders		(0.20	)		(0.60	)		(3.36	)		(3.98	)		(1.22	)
Redemption Fees
Redemption fees added to paid in capital (a)(b)		0.00			0.00			0.00			0.00			0.00
Increase from regulatory settlements		0.01			—			—			—			—
Net Asset Value, End of Period	$	33.22		$	22.41		$	42.46		$	39.39		$	32.71
Total Return (c)		49.36	%		(46.41	)%		16.25	%(d)		33.26	%(d)		20.57	%(d)
Ratios to Average Net Assets/Supplemental Data
Net expenses (e)		2.03	%		1.90	%		1.81	%		1.89	%		2.01	%
Net investment income/(loss) (e)		0.29	%		0.77	%		0.08	%		(0.01	)%		0.08	%
Waiver/Reimbursement		—			—			0.01	%		0.02	%		0.02	%
Portfolio turnover rate		31	%		38	%		28	%		31	%		27	%
Net assets at end of period (000s)	$	38,835		$	39,153		$	103,631		$	94,165		$	73,572

(a)  Per share data was calculated using the average shares outstanding during the period.

(b)  Rounds to less than $0.01 per share.

(c)  Total return at net asset value assuming all distributions reinvested and no contingent deferred sales charge.

(d)  Had the Advisor and/or Transfer Agent not waived fees and/or reimbursed a portion of expenses, total return would have been reduced.

(e)  The benefits derived from custody fees paid indirectly had an impact of less than 0.01%.

Class C Shares	Year Ended December 31,
Selected data for a share outstanding throughout each period	2009			2008			2007			2006			2005
Net Asset Value, Beginning of Period	$	22.30		$	42.32		$	39.35		$	32.68		$	28.19
Income from Investment Operations
Net investment income/(loss) (a)		0.02			0.21			(0.06	)		(0.05	)		(0.00	)(b)
Net realized and unrealized gain/(loss)		10.89			(19.63	)		6.39			10.66			5.71
Total from Investment Operations		10.91			(19.42	)		6.33			10.61			5.71
Less Distributions to Shareholders
From net investment income		(0.14	)		—			(0.00	)(b)		(0.03	)		(0.14	)
From net realized gains		—			(0.60	)		(3.36	)		(3.91	)		(1.08	)
Total Distributions to Shareholders		(0.14	)		(0.60	)		(3.36	)		(3.94	)		(1.22	)
Redemption Fees
Redemption fees added to paid in capital (a)(b)		0.00			0.00			0.00			0.00			0.00
Increase from regulatory settlements		0.01			—			—			—			—
Net Asset Value, End of Period	$	33.08		$	22.30		$	42.32		$	39.35		$	32.68
Total Return (c)		49.12	%		(46.50	)%		16.01	%(d)		33.14	%(d)		20.45	%(d)
Ratios to Average Net Assets/Supplemental Data
Net expenses (e)		2.17	%		2.08	%		1.99	%		2.01	%		2.09	%
Net investment income/(loss) (e)		0.07	%		0.60	%		(0.14	)%		(0.14	)%		(0.01	)%
Waiver/Reimbursement		—			—			0.00	%(f)		0.01	%		0.02	%
Portfolio turnover rate		31	%		38	%		28	%		31	%		27	%
Net assets at end of period (000s)	$	85,625		$	62,906		$	153,416		$	99,425		$	47,325

(a)  Per share data was calculated using the average shares outstanding during the period.

(b)  Rounds to less than $0.01 per share.

(c)  Total return at net asset value assuming all distributions reinvested and no contingent deferred sales charge.

(d)  Had the Advisor and/or Transfer Agent not waived fees and/or reimbursed a portion of expenses, total return would have been reduced.

(e)  The benefits derived from custody fees paid indirectly had an impact of less than 0.01%.

(f)  Rounds to less than 0.01%.

See accompanying notes to financial statements.

75

Columbia Acorn Family of Funds

Financial Highlights, continued

Columbia Acorn USA

Class A Shares	Year Ended December 31,
Selected data for a share outstanding throughout each period	2009			2008			2007			2006			2005
Net Asset Value, Beginning of Period	$	15.90		$	27.23		$	28.02		$	26.52		$	24.77
Income from Investment Operations
Net investment loss (a)		(0.11	)		(0.14	)		(0.09	)(b)		(0.10	)		(0.01	)
Net realized and unrealized gain/(loss)		6.64			(10.23	)		1.01			2.21			3.13
Total from Investment Operations		6.53			(10.37	)		0.92			2.11			3.12
Less Distributions to Shareholders
From net realized gains		—			(0.96	)		(1.71	)		(0.61	)		(1.37	)
Increase from regulatory settlements		—	(c)		—			—			—			—
Net Asset Value, End of Period	$	22.43		$	15.90		$	27.23		$	28.02		$	26.52
Total Return (d)		41.07	%		(39.38	)%		3.18	%(e)(f)		7.95	%(e)		12.68	%(e)
Ratios to Average Net Assets/Supplemental Data
Net expenses (g)		1.32	%		1.29	%		1.25	%		1.26	%		1.31	%
Net investment loss (g)		(0.64	)%		(0.60	)%		(0.29	)%		(0.35	)%		(0.02	)%
Waiver/Reimbursement		—			—			0.00	%(h)		0.01	%		0.01	%
Portfolio turnover rate		28	%		23	%		21	%		13	%		13	%
Net assets at end of period (000s)	$	178,605		$	136,597		$	245,085		$	245,552		$	168,922

(a)  Per share data was calculated using the average shares outstanding during the period.

(b)  Net investment income per share includes special dividends. The effect of these dividends amounted to $0.09 per share.

(c)  Rounds to less than $0.01 per share.

(d)  Total return at net asset value assuming all distributions reinvested and no initial sales charge or contingent deferred sales charge.

(e)  Had the Advisor and/or Transfer Agent not waived fees and/or reimbursed a portion of expenses, total return would have been reduced.

(f)  Total return includes a voluntary reimbursement by the Advisor for a realized investment loss due to a trading error. This reimbursement increased total return and net asset value per share by less than 0.01% and less than $0.01, respectively.

(g)  The benefits derived from custody fees paid indirectly had an impact of less than 0.01%.

(h)  Rounds to less than 0.01%.

Class B Shares	Year Ended December 31,
Selected data for a share outstanding throughout each period	2009			2008			2007			2006			2005
Net Asset Value, Beginning of Period	$	14.98		$	25.87		$	26.87		$	25.61		$	24.14
Income from Investment Operations
Net investment loss (a)		(0.22	)		(0.27	)		(0.25	)(b)		(0.27	)		(0.18	)
Net realized and unrealized gain/(loss)		6.23			(9.66	)		0.96			2.14			3.02
Total from Investment Operations		6.01			(9.93	)		0.71			1.87			2.84
Less Distributions to Shareholders
From net realized gains		—			(0.96	)		(1.71	)		(0.61	)		(1.37	)
Increase from regulatory settlements		—	(c)		—			—			—			—
Net Asset Value, End of Period	$	20.99		$	14.98		$	25.87		$	26.87		$	25.61
Total Return (d)		40.12	%		(39.75	)%		2.53	%(e)(f)		7.29	%(e)		11.84	%(e)
Ratios to Average Net Assets/Supplemental Data
Net expenses (g)		2.02	%		1.92	%		1.85	%		1.93	%		2.00	%
Net investment loss (g)		(1.33	)%		(1.24	)%		(0.87	)%		(1.01	)%		(0.72	)%
Waiver/Reimbursement		—			—			0.01	%		0.02	%		0.01	%
Portfolio turnover rate		28	%		23	%		21	%		13	%		13	%
Net assets at end of period (000s)	$	20,903		$	23,633		$	53,820		$	65,040		$	73,168

(a)  Per share data was calculated using the average shares outstanding during the period.

(b)  Net investment income per share includes special dividends. The effect of these dividends amounted to $0.09 per share.

(c)  Rounds to less than $0.01 per share.

(d)  Total return at net asset value assuming all distributions reinvested and no contingent deferred sales charge.

(e)  Had the Advisor and/or Transfer Agent not waived fees and/or reimbursed a portion of expenses, total return would have been reduced.

(f)  Total return includes a voluntary reimbursement by the Advisor for a realized investment loss due to a trading error. This reimbursement increased total return and net asset value per share by less than 0.01% and less than $0.01, respectively.

(g)  The benefits derived from custody fees paid indirectly had an impact of less than 0.01%.

Class C Shares	Year Ended December 31,
Selected data for a share outstanding throughout each period	2009			2008			2007			2006			2005
Net Asset Value, Beginning of Period	$	14.89		$	25.77		$	26.81		$	25.59		$	24.14
Income from Investment Operations
Net investment loss (a)		(0.24	)		(0.30	)		(0.30	)(b)		(0.30	)		(0.20	)
Net realized and unrealized gain/(loss)		6.19			(9.62	)		0.97			2.13			3.02
Total from Investment Operations		5.95			(9.92	)		0.67			1.83			2.82
Less Distributions to Shareholders
From net realized gains		—			(0.96	)		(1.71	)		(0.61	)		(1.37	)
Increase from regulatory settlements		—	(c)		—			—			—			—
Net Asset Value, End of Period	$	20.84		$	14.89		$	25.77		$	26.81		$	25.59
Total Return (d)		39.96	%		(39.87	)%		2.39	%(e)(f)		7.14	%(e)		11.76	%(e)
Ratios to Average Net Assets/Supplemental Data
Net expenses (g)		2.13	%		2.08	%		2.03	%		2.05	%		2.10	%
Net investment loss (g)		(1.45	)%		(1.39	)%		(1.07	)%		(1.14	)%		(0.81	)%
Waiver/Reimbursement		—			—			0.00	%(h)		0.01	%		0.01	%
Portfolio turnover rate		28	%		23	%		21	%		13	%		13	%
Net assets at end of period (000s)	$	32,508		$	25,899		$	50,743		$	55,306		$	42,844

(a)  Per share data was calculated using the average shares outstanding during the period.

(b)  Net investment income per share includes special dividends. The effect of these dividends amounted to $0.09 per share.

(c)  Rounds to less than $0.01 per share.

(d)  Total return at net asset value assuming all distributions reinvested and no contingent deferred sales charge.

(e)  Had the Advisor and/or Transfer Agent not waived fees and/or reimbursed a portion of expenses, total return would have been reduced.

(f)  Total return includes a voluntary reimbursement by the Advisor for a realized investment loss due to a trading error. This reimbursement increased total return and net asset value per share by less than 0.01% and less than $0.01, respectively.

(g)  The benefits derived from custody fees paid indirectly had an impact of less than 0.01%.

(h)  Rounds to less than 0.01%.

See accompanying notes to financial statements.

76

Columbia Acorn International Select

Class A Shares	Year Ended December 31,
Selected data for a share outstanding throughout each period	2009			2008			2007			2006			2005
Net Asset Value, Beginning of Period	$	17.99		$	31.74		$	27.68		$	20.36		$	17.85
Income from Investment Operations
Net investment income (a)		0.10			0.20			0.04	(b)		0.03			0.06
Net realized and unrealized gain/(loss)		5.43			(13.41	)		5.91			7.29			2.69
Total from Investment Operations		5.53			(13.21	)		5.95			7.32			2.75
Less Distributions to Shareholders
From net investment income		(0.15	)		—			(0.12	)		—			(0.24	)
From net realized gains		—			(0.54	)		(1.77	)		—			—
Total Distributions to Shareholders		(0.15	)		(0.54	)		(1.89	)		—			(0.24	)
Redemption Fees
Redemption fees added to paid in capital (a)(c)		0.00			0.00			0.00			0.00			0.00
Increase from regulatory settlements		0.02			—			—			—			—
Net Asset Value, End of Period	$	23.39		$	17.99		$	31.74		$	27.68		$	20.36
Total Return (d)		31.01	%		(42.30	)%		21.50	%(e)		35.97	%(e)		15.60	%(e)
Ratios to Average Net Assets/Supplemental Data
Net expenses (f)		1.56	%		1.54	%		1.49	%		1.58	%		1.70	%
Net investment income (f)		0.53	%		0.78	%		0.11	%		0.11	%		0.34	%
Waiver/Reimbursement		—			—			0.00	%(g)		0.02	%		0.10	%
Portfolio turnover rate		56	%		68	%		57	%		47	%		39	%
Net assets at end of period (000s)	$	64,664		$	46,522		$	48,538		$	22,599		$	10,219

(a)  Per share data was calculated using the average shares outstanding during the period.

(b)  Net investment income per share includes special dividends. The effect of these dividends amounted to $0.07 per share.

(c)  Rounds to less than $0.01 per share.

(d)  Total return at net asset value assuming all distributions reinvested and no initial sales charge or contingent deferred sales charge.

(e)  Had the Advisor and/or Transfer Agent not waived fees and/or reimbursed a portion of expenses, total return would have been reduced.

(f)  The benefits derived from custody fees paid indirectly had an impact of less than 0.01%.

(g)  Rounds to less than 0.01%.

Class B Shares	Year Ended December 31,
Selected data for a share outstanding throughout each period	2009			2008			2007			2006			2005
Net Asset Value, Beginning of Period	$	17.16		$	30.50		$	26.73		$	19.80		$	17.36
Income from Investment Operations
Net investment income/(loss) (a)		(0.01	)		0.04			(0.13	)(b)		(0.12	)		(0.03	)
Net realized and unrealized gain/(loss)		5.17			(12.84	)		5.67			7.05			2.61
Total from Investment Operations		5.16			(12.80	)		5.54			6.93			2.58
Less Distributions to Shareholders
From net investment income		—			—			—			—			(0.14	)
From net realized gains		—			(0.54	)		(1.77	)		—			—
Total Distributions to Shareholders		—			(0.54	)		(1.77	)		—			(0.14	)
Redemption Fees
Redemption fees added to paid in capital (a)(c)		0.00			0.00			0.00			0.00			0.00
Increase from regulatory settlements		0.02			—			—			—			—
Net Asset Value, End of Period	$	22.34		$	17.16		$	30.50		$	26.73		$	19.80
Total Return (d)		30.19	%(e)		(42.68	)%		20.69	%(e)		35.00	%(e)		14.97	%(e)
Ratios to Average Net Assets/Supplemental Data
Net expenses (f)		2.20	%		2.17	%		2.10	%		2.25	%		2.30	%
Net investment income/(loss) (f)		(0.05	)%		0.16	%		(0.45	)%		(0.53	)%		(0.16	)%
Waiver/Reimbursement		0.12	%		—			0.01	%		0.04	%		0.28	%
Portfolio turnover rate		56	%		68	%		57	%		47	%		39	%
Net assets at end of period (000s)	$	3,887		$	4,444		$	11,941		$	9,787		$	6,594

(a)  Per share data was calculated using the average shares outstanding during the period.

(b)  Net investment income per share includes special dividends. The effect of these dividends amounted to $0.07 per share.

(c)  Rounds to less than $0.01 per share.

(d)  Total return at net asset value assuming all distributions reinvested and no contingent deferred sales charge.

(e)  Had the Advisor and/or Transfer Agent not waived fees and/or reimbursed a portion of expenses, total return would have been reduced.

(f)  The benefits derived from custody fees paid indirectly had an impact of less than 0.01%.

Class C Shares	Year Ended December 31,
Selected data for a share outstanding throughout each period	2009			2008			2007			2006			2005
Net Asset Value, Beginning of Period	$	17.08		$	30.42		$	26.70		$	19.80		$	17.38
Income from Investment Operations
Net investment income/(loss) (a)		(0.06	)		0.00	(b)		(0.20	)(c)		(0.15	)		(0.05	)
Net realized and unrealized gain/(loss)		5.17			(12.80	)		5.69			7.05			2.60
Total from Investment Operations		5.11			(12.80	)		5.49			6.90			2.55
Less Distributions to Shareholders
From net investment income		—			—			—			—			(0.13	)
From net realized gains		—			(0.54	)		(1.77	)		—			—
Total Distributions to Shareholders		—			(0.54	)		(1.77	)		—			(0.13	)
Redemption Fees
Redemption fees added to paid in capital (a)(b)		0.00			0.00			0.00			0.00			0.00
Increase from regulatory settlements		0.02			—			—			—			—
Net Asset Value, End of Period	$	22.21		$	17.08		$	30.42		$	26.70		$	19.80
Total Return (d)		30.04	%		(42.79	)%		20.53	%(e)		34.85	%(e)		14.77	%(e)
Ratios to Average Net Assets/Supplemental Data
Net expenses (f)		2.42	%		2.34	%		2.29	%		2.38	%		2.45	%
Net investment income/(loss) (f)		(0.30	)%		0.01	%		(0.68	)%		(0.67	)%		(0.30	)%
Waiver/Reimbursement		—			—			0.01	%		0.02	%		0.17	%
Portfolio turnover rate		56	%		68	%		57	%		47	%		39	%
Net assets at end of period (000s)	$	11,096		$	9,747		$	13,023		$	7,060		$	4,083

(a)  Per share data was calculated using the average shares outstanding during the period.

(b)  Rounds to less than $0.01 per share.

(c)  Net investment income per share includes special dividends. The effect of these dividends amounted to $0.07 per share.

(d)  Total return at net asset value assuming all distributions reinvested and no contingent deferred sales charge.

(e)  Had the Advisor and/or Transfer Agent not waived fees and/or reimbursed a portion of expenses, total return would have been reduced.

(f)  The benefits derived from custody fees paid indirectly had an impact of less than 0.01%.

See accompanying notes to financial statements.

77

Columbia Acorn Family of Funds

Financial Highlights, continued

Columbia Acorn Select

Class A Shares	Year Ended December 31,
Selected data for a share outstanding throughout each period	2009			2008			2007			2006			2005
Net Asset Value, Beginning of Period	$	13.77		$	27.89		$	26.18		$	22.47		$	20.83
Income from Investment Operations
Net investment loss (a)		(0.14	)		(0.18	)		(0.15	)		(0.13	)		(0.09	)
Net realized and unrealized gain/(loss)		9.18			(13.25	)		2.50			4.45			2.32
Total from Investment Operations		9.04			(13.43	)		2.35			4.32			2.23
Less Distributions to Shareholders
From net investment income		—			—			—			(0.02	)		—
From net realized gains		—			(0.69	)		(0.64	)		(0.59	)		(0.59	)
Total Distributions to Shareholders		—			(0.69	)		(0.64	)		(0.61	)		(0.59	)
Net Asset Value, End of Period	$	22.81		$	13.77		$	27.89		$	26.18		$	22.47
Total Return (b)		65.65	%		(49.31	)%(c)		8.92	%(d)		19.32	%(d)		10.78	%(d)
Ratios to Average Net Assets/Supplemental Data
Net expenses (e)		1.30	%		1.24	%		1.19	%		1.24	%		1.26	%
Net investment loss (e)		(0.78	)%		(0.80	)%		(0.52	)%		(0.54	)%		(0.42	)%
Waiver/Reimbursement		—			—			0.00	%(f)		0.03	%		0.03	%
Portfolio turnover rate		19	%		28	%		14	%		21	%		19	%
Net assets at end of period (000s)	$	522,443		$	395,794		$	1,117,941		$	940,857		$	744,178

(a)  Per share data was calculated using the average shares outstanding during the period.

(b)  Total return at net asset value assuming all distributions reinvested and no initial sales charge or contingent deferred sales charge.

(c)  Total return includes a voluntary reimbursement by the Advisor for a realized investment loss due to a trading error. This reimbursement increased total return and net asset value per share by 0.101% and $0.01, respectively.

(d)  Had the Advisor and/or Transfer Agent not waived fees and/or reimbursed a portion of expenses, total return would have been reduced.

(e)  The benefits derived from custody fees paid indirectly had an impact of less than 0.01%.

(f)  Rounds to less than 0.01%.

Class B Shares	Year Ended December 31,
Selected data for a share outstanding throughout each period	2009			2008			2007			2006			2005
Net Asset Value, Beginning of Period	$	13.02		$	26.57		$	25.13		$	21.71		$	20.23
Income from Investment Operations
Net investment loss (a)		(0.24	)		(0.31	)		(0.31	)		(0.28	)		(0.23	)
Net realized and unrealized gain/(loss)		8.63			(12.55	)		2.39			4.29			2.24
Total from Investment Operations		8.39			(12.86	)		2.08			4.01			2.01
Less Distributions to Shareholders
From net realized gains		—			(0.69	)		(0.64	)		(0.59	)		(0.53	)
Net Asset Value, End of Period	$	21.41		$	13.02		$	26.57		$	25.13		$	21.71
Total Return (b)		64.44	%		(49.62	)%(c)		8.22	%(d)		18.54	%(d)		10.01	%(d)
Ratios to Average Net Assets/Supplemental Data
Net expenses (e)		2.01	%		1.87	%		1.79	%		1.91	%		1.99	%
Net investment loss (e)		(1.49	)%		(1.43	)%		(1.12	)%		(1.21	)%		(1.15	)%
Waiver/Reimbursement		—			—			0.01	%		0.03	%		0.03	%
Portfolio turnover rate		19	%		28	%		14	%		21	%		19	%
Net assets at end of period (000s)	$	88,004		$	73,152		$	199,182		$	214,260		$	206,441

(a)  Per share data was calculated using the average shares outstanding during the period.

(b)  Total return at net asset value assuming all distributions reinvested and no contingent deferred sales charge.

(c)  Total return includes a voluntary reimbursement by the Advisor for a realized investment loss due to a trading error. This reimbursement increased total return and net asset value per share by 0.101% and $0.01, respectively.

(d)  Had the Advisor and/or Transfer Agent not waived fees and/or reimbursed a portion of expenses, total return would have been reduced.

(e)  The benefits derived from custody fees paid indirectly had an impact of less than 0.01%.

Class C Shares	Year Ended December 31,
Selected data for a share outstanding throughout each period	2009			2008			2007			2006			2005
Net Asset Value, Beginning of Period	$	12.94		$	26.46		$	25.07		$	21.69		$	20.23
Income from Investment Operations
Net investment loss (a)		(0.26	)		(0.34	)		(0.36	)		(0.31	)		(0.25	)
Net realized and unrealized gain/(loss)		8.57			(12.49	)		2.39			4.28			2.24
Total from Investment Operations		8.31			(12.83	)		2.03			3.97			1.99
Less Distributions to Shareholders
From net realized gains		—			(0.69	)		(0.64	)		(0.59	)		(0.53	)
Net Asset Value, End of Period	$	21.25		$	12.94		$	26.46		$	25.07		$	21.69
Total Return (b)		64.22	%		(49.71	)%(c)		8.04	%(d)		18.37	%(d)		9.91	%(d)
Ratios to Average Net Assets/Supplemental Data
Net expenses (e)		2.14	%		2.04	%		1.98	%		2.04	%		2.08	%
Net investment loss (e)		(1.62	)%		(1.60	)%		(1.31	)%		(1.34	)%		(1.24	)%
Waiver/Reimbursement		—			—			0.00	%(f)		0.03	%		0.03	%
Portfolio turnover rate		19	%		28	%		14	%		21	%		19	%
Net assets at end of period (000s)	$	93,121		$	70,962		$	197,100		$	173,152		$	149,160

(a)  Per share data was calculated using the average shares outstanding during the period.

(b)  Total return at net asset value assuming all distributions reinvested and no contingent deferred sales charge.

(c)  Total return includes a voluntary reimbursement by the Advisor for a realized investment loss due to a trading error. This reimbursement increased total return and net asset value per share by 0.101% and $0.01, respectively.

(d)  Had the Advisor and/or Transfer Agent not waived fees and/or reimbursed a portion of expenses, total return would have been reduced.

(e)  The benefits derived from custody fees paid indirectly had an impact of less than 0.01%.

(f)  Rounds to less than 0.01%.

See accompanying notes to financial statements.

78

Columbia Thermostat Fund

Class A Shares	Year Ended December 31,
Selected data for a share outstanding throughout each period	2009			2008			2007			2006			2005
Net Asset Value, Beginning of Period	$	8.26		$	12.31		$	12.59		$	12.49		$	13.11
Income from Investment Operations
Net investment income (a)		0.11			0.22			0.49			0.45			0.39
Net realized and unrealized gain/(loss)		2.53			(3.98	)		0.53			0.84			0.29
Total from Investment Operations		2.64			(3.76	)		1.02			1.29			0.68
Less Distributions to Shareholders
From net investment income		(0.00	)(b)		(0.22	)		(0.51	)		(0.47	)		(0.39	)
From net realized gains		—			(0.07	)		(0.79	)		(0.72	)		(0.91	)
Total Distributions to Shareholders		(0.00	)(b)		(0.29	)		(1.30	)		(1.19	)		(1.30	)
Net Asset Value, End of Period	$	10.90		$	8.26		$	12.31		$	12.59		$	12.49
Total Return (c)(d)		31.98	%		(30.67	)%		8.19	%		10.56	%		5.25	%
Ratios to Average Net Assets/Supplemental Data
Net expenses (e)(f)		0.50	%		0.50	%		0.50	%		0.50	%		0.50	%
Net investment income (f)		1.17	%		1.99	%		3.75	%		3.53	%		2.97	%
Waiver/Reimbursement		0.28	%		0.18	%		0.18	%		0.20	%		0.15	%
Portfolio turnover rate		17	%		130	%		128	%		66	%		96	%
Net assets at end of period (000s)	$	42,976		$	41,032		$	53,246		$	58,013		$	71,034

(a)  Per share data was calculated using the average shares outstanding during the period. Recognition of net investment income by the Fund is affected by the timing of the declaration of dividends by the underlying investment companies in which the Fund invests.

(b)  Round to less than $(0.01) per share.

(c)  Total return at net asset value assuming all distributions reinvested and no initial sales charge or contingent deferred sales charge.

(d)  Had the Advisor and/or Transfer Agent not waived fees and/or reimbursed a portion of expenses, total return would have been reduced.

(e)  Does not include expenses of the investment companies in which the Fund invests.

(f)  The benefits derived from custody fees paid indirectly had an impact of less than 0.01%.

Class B Shares	Year Ended December 31,
Selected data for a share outstanding throughout each period	2009			2008			2007			2006			2005
Net Asset Value, Beginning of Period	$	8.32		$	12.38		$	12.62		$	12.51		$	13.14
Income from Investment Operations
Net investment income (a)		0.06			0.16			0.42			0.38			0.31
Net realized and unrealized gain/(loss)		2.55			(4.00	)		0.54			0.84			0.28
Total from Investment Operations		2.61			(3.84	)		0.96			1.22			0.59
Less Distributions to Shareholders
From net investment income		—			(0.15	)		(0.41	)		(0.39	)		(0.31	)
From net realized gains		—			(0.07	)		(0.79	)		(0.72	)		(0.91	)
Total Distributions to Shareholders		—			(0.22	)		(1.20	)		(1.11	)		(1.22	)
Net Asset Value, End of Period	$	10.93		$	8.32		$	12.38		$	12.62		$	12.51
Total Return (b)(c)		31.37	%		(31.10	)%		7.71	%		9.91	%		4.56	%
Ratios to Average Net Assets/Supplemental Data
Net expenses (d)(e)		1.00	%		1.00	%		1.00	%		1.06	%		1.10	%
Net investment income (e)		0.64	%		1.45	%		3.25	%		2.99	%		2.39	%
Waiver/Reimbursement		0.32	%		0.20	%		0.19	%		0.23	%		0.19	%
Portfolio turnover rate		17	%		130	%		128	%		66	%		96	%
Net assets at end of period (000s)	$	32,758		$	36,673		$	67,709		$	72,367		$	78,444

(a)  Per share data was calculated using the average shares outstanding during the period. Recognition of net investment income by the Fund is affected by the timing of the declaration of dividends by the underlying investment companies in which the Fund invests.

(b)  Total return at net asset value assuming all distributions reinvested and no contingent deferred sales charge.

(c)  Had the Advisor and/or Transfer Agent not waived fees and/or reimbursed a portion of expenses, total return would have been reduced.

(d)  Does not include expenses of the investment companies in which the Fund invests.

(e)  The benefits derived from custody fees paid indirectly had an impact of less than 0.01%.

Class C Shares	Year Ended December 31,
Selected data for a share outstanding throughout each period	2009			2008			2007			2006			2005
Net Asset Value, Beginning of Period	$	8.33		$	12.37		$	12.62		$	12.51		$	13.13
Income from Investment Operations
Net investment income (a)		0.03			0.13			0.39			0.36			0.29
Net realized and unrealized gain/(loss)		2.55			(3.97	)		0.53			0.84			0.29
Total from Investment Operations		2.58			(3.84	)		0.92			1.20			0.58
Less Distributions to Shareholders
From net investment income		—			(0.13	)		(0.38	)		(0.37	)		(0.29	)
From net realized gains		—			(0.07	)		(0.79	)		(0.72	)		(0.91	)
Total Distributions to Shareholders		—			(0.20	)		(1.17	)		(1.09	)		(1.20	)
Net Asset Value, End of Period	$	10.91		$	8.33		$	12.37		$	12.62		$	12.51
Total Return (b)(c)		30.97	%		(31.20	)%		7.36	%		9.72	%		4.49	%
Ratios to Average Net Assets/Supplemental Data
Net expenses (d)(e)		1.25	%		1.25	%		1.25	%		1.25	%		1.25	%
Net investment income (e)		0.39	%		1.23	%		3.02	%		2.81	%		2.21	%
Waiver/Reimbursement		0.30	%		0.20	%		0.19	%		0.23	%		0.19	%
Portfolio turnover rate		17	%		130	%		128	%		66	%		96	%
Net assets at end of period (000s)	$	21,090		$	24,383		$	26,908		$	27,375		$	28,316

(a)  Per share data was calculated using the average shares outstanding during the period. Recognition of net investment income by the Fund is affected by the timing of the declaration of dividends by the underlying investment companies in which the Fund invests.

(b)  Total return at net asset value assuming all distributions reinvested and no contingent deferred sales charge.

(c)  Had the Advisor and/or Transfer Agent not waived fees and/or reimbursed a portion of expenses, total return would have been reduced.

(d)  Does not include expenses of the investment companies in which the Fund invests.

(e)  The benefits derived from custody fees paid indirectly had an impact of less than 0.01%.

See accompanying notes to financial statements.

79

Columbia Acorn Family of Funds

Notes to Financial Statements

1.  Nature of Operations

Columbia Acorn Fund, Columbia Acorn International, Columbia Acorn USA, Columbia Acorn International Select, Columbia Acorn Select and Columbia Thermostat Fund (the "Funds") are each a series of Columbia Acorn Trust (the "Trust"), an open-end management investment company organized as a Massachusetts business trust. The investment objective of each Fund is to seek long-term capital appreciation. Columbia Thermostat Fund pursues its investment objective by investing in shares of other mutual funds. As a "fund of funds," under normal circumstances the Fund allocates at least 95% of its net assets among a selected group of stock and bond mutual funds ("portfolio funds") according to the current level of the Standard & Poor's 500 Index in relation to predetermined ranges set by the Advisor. The Fund may invest up to 5% of its net assets plus any cash received that day in cash, repurchase agreements, high quality short-term paper and government securities.

Each Fund may issue an unlimited number of shares. Each Fund currently has four classes of shares: Class A, Class B, Class C and Class Z. Effective February 29, 2008, the Funds no longer offer Class B shares (other than through dividend reinvestment).

Class A shares are sold with a front-end sales charge. Class A shares bought without an initial sales charge in accounts aggregating $1 million up to $50 million at the time of purchase are subject to a 1.00% contingent deferred sales charge ("CDSC") if the shares are redeemed within 12 months of the date of purchase.

Class B shares are subject to a CDSC if redeemed within six years of purchase. Class B shares will convert to Class A shares automatically eight years after purchase.

Class C shares are offered at net asset value but are subject to a CDSC on redemptions made within one year after purchase.

Class Z shares are offered at net asset value. There are certain restrictions on who may purchase Class Z shares. Generally, Class Z shares of a Fund may be exchanged for shares of another fund distributed by Columbia Management Distributors, Inc. at no additional charge.

Columbia Acorn International and Columbia Acorn International Select impose a 2.00% redemption fee on shares that are redeemed within 60 days or less of purchase. See the discussion of Fund policies regarding redemption fees in the Funds' prospectuses for more information.

The financial highlights for the Fund's Class Z shares are presented in a separate annual report.

Investment income, realized and unrealized gains and losses, and certain fund-level expenses are allocated pro rata on the basis of the relative net assets of all classes, except that each class bears certain expenses specific to that class such as distribution services, transfer agency, and certain other class specific expenses. Differences in class expenses may result in payment of different dividend distributions for each class. All of the Funds' share classes have equal rights with respect to voting, subject to Fund or class specific matters.

On September 29, 2009, Bank of America Corporation, the indirect parent company of Columbia Wanger Asset Management, L.P. ("CWAM") entered into an agreement to sell a portion of the asset management business of Columbia Management Group, LLC ("Columbia Management") to Ameriprise Financial, Inc. The transaction ("Transaction") includes a sale of CWAM. The Transaction is subject to certain approvals and other conditions to closing, and is currently expected to close in the spring of 2010.

2.  Significant Accounting Policies

The preparation of financial statements in accordance with accounting principles generally accepted in the United States of America ("GAAP") requires management to make certain estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosures of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. Actual results could differ from those estimates.

Management has evaluated the events and transactions that have occurred through February 18, 2010, the date the financial statements were issued, and noted no items requiring adjustment of the financial statements or additional disclosures. The following is a summary of significant accounting policies consistently followed by the Funds in the preparation of their financial statements.

>Security valuation

Securities of the Funds are valued at market value or, if a market quotation for a security is not readily available or is deemed not to be reliable because of events or circumstances that have occurred between the market quotation and the time as of which the security is to be valued, the security is valued at a fair value determined in good faith under consistently applied procedures established by the Board of Trustees. With respect to Columbia Thermostat Fund, investments in portfolio funds are valued at their net asset values as reported by the portfolio funds. A security traded on a securities exchange or in an over-the-counter market in which transaction prices are reported is valued at the last sales price at the time of valuation. A security traded principally on NASDAQ is valued at the

80

NASDAQ official closing price. Mutual Funds and Exchange Traded Funds are valued at their closing net asset value as reported to NASDAQ. A security for which there is no reported sale on the valuation date is valued at the latest bid quotation. Short-term investments maturing in 60 days or less are valued at amortized cost, which approximates market value. A security for which a market quotation is not readily available and any other assets are valued at its fair value determined in good faith under consistently applied procedures established by the Board of Trustees. The Funds have retained an independent statistical fair value pricing service that employs a systematic methodology to assist in the fair valuation process for securities principally traded in a foreign market in order to adjust for possible changes in value that may occur between the close of the foreign exchange and the time as of which the securities are to be v alued. If a security is valued at fair value, that value may be different from the last quoted market price for the security.

Various inputs are used in determining the value of each Fund's investments. These inputs are summarized in the three broad levels listed below:

• Level 1 – quoted prices in active markets for identical securities

• Level 2 – other significant observable inputs (including quoted prices for similar securities, interest rates, prepayment speeds, credit risk and others)

• Level 3 – significant unobservable inputs (including management's own assumptions in determining the value of investments)

The inputs or methodologies used for valuing securities are not necessarily an indication of the risks associated with investing in those securities.

Examples of the types of securities in which the Funds would typically invest and how they are classified within this hierarchy are as follows. Typical Level 1 securities include exchange traded domestic equities, mutual funds whose NAVs are published each day and exchange traded foreign equities that are not statistically fair valued. Typical Level 2 securities include exchange traded foreign equities that are statistically fair valued, forward foreign currency exchange contracts and short-term investments valued at amortized cost. Additionally, securities fair valued by the Fund's Valuation Committee that rely on significant observable inputs are also included in level 2. Typical Level 3 securities include any security fair valued by the Funds' Valuation Committee that relies on significant unobservable inputs.

>Repurchase agreements

Each Fund may engage in repurchase agreement transactions. Each Fund, through its custodian, receives delivery of underlying securities collateralizing repurchase agreements. The counterparty is required to maintain collateral that is at all times at least equal to the repurchase price including interest. In the event of default or bankruptcy by the counterparty to the agreement, realization and/or retention of the collateral may be subject to legal proceedings.

>Foreign currency translations

Values of investments denominated in foreign currencies are converted into U.S. dollars using the New York spot market rate of exchange at the time of valuation. Purchases and sales of investments and dividend and interest income are translated into U.S. dollars using the spot market rate of exchange prevailing on the respective dates of such transactions. The gain or loss resulting from changes in foreign exchange rates is included with net realized and unrealized gain or loss from investments, as appropriate.

>Forward foreign currency exchange contracts

Columbia Acorn International may enter into forward foreign currency exchange contracts in order to seek to minimize the risk from adverse changes in the relationship between the U.S. dollar and foreign currencies. A forward foreign currency exchange contract is a commitment to purchase or sell a foreign currency at a future date at a negotiated forward rate. Forward foreign currency exchange contracts are valued at the interpolated forward exchange rate of the underlying currencies and any market gain or loss, arising from the difference between the original value and the current value of such contract, is included as a component of unrealized gain/(loss) on the Statements of Operations. Open forward foreign currency exchange contracts, if any, are disclosed in the Notes to the Statement of Investments. As forward foreign currency exchange contracts are closed the resulting gain or loss, arising from the difference between the original value of the contract and the closing value of such contract, is included as a component of realized gain/(loss) on the Statements of Operations.

A forward foreign currency exchange contract would limit the risk of loss due to a decline in the value of a particular currency; however, it also would limit any potential gain that might result should the value of the currency increase instead of decrease. These contracts may involve market risk in excess of the unrealized gain or loss reflected on the Statements of Assets and Liabilities. In addition, a Fund could be exposed to counterparty risks if counterparties to the contracts are unable

81

Columbia Acorn Family of Funds

Notes to Financial Statements, continued

to meet the terms of their contracts. The counterparty risk exposure is, therefore, closely monitored and contracts are only executed with high credit quality financial institutions.

A Fund may use forward foreign currency exchange contracts to buy or sell a foreign currency when the Advisor believes it has exposure to a foreign currency which may suffer or enjoy a movement against another foreign currency to which the Fund has exposure. A Fund will not attempt to hedge all of its foreign portfolio positions.

For additional information on derivative instruments, please see Note 5.

>Securities lending

Each Fund may lend securities up to one-third of the value of its total assets to certain approved brokers, dealers and other financial institutions to earn additional income. In lending its securities, the Fund retains the benefits of owning the securities, including receipt of dividends or interest generated by the security. Each Fund also receives a fee for the loan. Each Fund has the ability to recall the loans at any time and could do so in order to vote proxies or to sell the loaned securities. Each loan is collateralized by cash that exceeds the value of the securities on loan. The market value of the loaned securities is determined daily at the close of business of each Fund and any additional required collateral is delivered to each Fund on the next business day. Each Fund has elected to invest the cash collateral in the Dreyfus Government Cash Management Fund, and the income earned is paid to each Fund, net of any fees remitted to Goldman Sachs Agency Lending as the lending agent and net of any borrower rebates. The Funds' advisor, CWAM, does not retain any fees earned by the lending program. Generally, in the event of borrower default, a Fund has the right to use the collateral to offset any losses incurred. In the event a Fund is delayed or prevented from exercising its right to dispose of the collateral, there may be a potential loss to a Fund. Some of these losses may be indemnified by the lending agent. Each Fund bears the risk of loss with respect to the investment of collateral.

The net lending income earned in 2009 by each Fund is included in the Statements of Operations.

>Security transactions and investment income

Security transactions, investment income and shareholder fund transactions are accounted for on the trade date (date the order to buy or sell is executed) and dividend income and realized gain distributions from other funds are recorded on the ex-dividend date, except that certain dividends from foreign securities are recorded as soon as the information is available to the Funds. Interest income is recorded on the accrual basis and includes amortization of discounts on debt obligations when required for federal income tax purposes. Realized gains and losses from security transactions are recorded on an identified cost basis.

Awards, if any, from class action litigation related to securities owned may be recorded as a reduction of cost of those securities. If the applicable securities are no longer owned, the proceeds are recorded as realized gains.

The Funds estimate the tax character of distributions from real estate investment trusts ("REITs"). Distributions received in excess of income are recorded as a reduction of the cost of the related investments. If the applicable securities are no longer owned, any distributions received in excess of income are recorded as realized gains.

>Restricted securities

Restricted securities are securities that may only be resold upon registration under federal securities laws or in transactions exempt from registration. In some cases, the issuer of restricted securities has agreed to register such securities for resale at the issuer's expense either upon demand by the Funds or in connection with another registered offering of the securities. Many restricted securities may be resold in the secondary market in transactions exempt from registration. Such restricted securities may be determined to be liquid under criteria established by the Board of Trustees.

>Fund share valuation

Fund shares are sold and redeemed on a continuing basis at net asset value, subject to any applicable sales charge. Net asset value per share is determined daily as of the close of trading on the New York Stock Exchange ("NYSE") on each day the NYSE is open for trading. Generally, income, expenses and realized and unrealized gain/(losses) of a Fund are allocated to each class proportionately on a daily basis for purposes of determining the net asset value of each class. The Rule 12b-1 service and distribution fees and transfer agency fees are charged to each specific class as expenses are incurred. Redemption fees are accounted for as an addition to paid in capital for purposes of determining the net asset value of each class.

>Custody fees/credits

Custody fees are reduced based on each Fund's cash balances maintained with the custodian. The amount is disclosed as a reduction of total expenses on the Statements of Operations.

82

>Federal income taxes

The Funds have complied with the provisions of the Internal Revenue Code available to regulated investment companies and, in the manner provided therein, distribute all their taxable income, as well as any net realized gain on sales of investments and foreign currency transactions reportable for federal income tax purposes. Columbia Thermostat Fund distributes all of its taxable income, as well as any net realized gain on sales of portfolio fund shares and any distributions of net realized gains received by the Fund from its portfolio funds, reportable for federal income tax purposes. Accordingly, the Funds paid no federal income taxes and no federal income tax provision was required.

>Foreign capital gains taxes

Realized gains in certain countries may be subject to foreign taxes at the fund level, at rates ranging from approximately 10% to 15%. The Funds accrue for such foreign taxes on net realized and unrealized gains at the appropriate rate for each jurisdiction.

>Distributions to Shareholders

Distributions to shareholders are recorded on the ex-dividend date.

>Indemnification

In the normal course of business, the Trust on behalf of the Funds enters into contracts that contain a variety of representations and warranties and that provide general indemnities. A Fund's maximum exposure under these arrangements is unknown, as this would involve future claims against the Fund. Also, under the Trust's organizational documents, the trustees and officers of the Trust are indemnified against certain liabilities that may arise out of their duties to the Trust. However, based on experience, the Funds expect the risk of loss due to these warranties and indemnities to be minimal.

3.  Federal Tax Information

The timing and character of income and capital gain distributions are determined in accordance with income tax regulations, which may differ from GAAP. Reclassifications are made to each Fund's capital accounts for permanent tax differences to reflect income and gains available for distribution (or available capital loss carryforwards) under income tax regulations.

For the year ended December 31, 2009, permanent book and tax basis differences resulting primarily from differing treatments for proceeds from litigation settlements, net operating losses, foreign currency transactions, passive foreign investment company ("PFIC") adjustments and foreign capital gains tax adjustments were identified and reclassified among the components of each Fund's net assets as follows:

	Undistributed/ (Overdistributed) or (Accumulated) Net Investment Income (Loss)			Accumulated Net Realized Gain/(Loss)			Paid-in Capital
(in thousands)
Columbia Acorn Fund	$	(189	)	$	229		$	(40	)
Columbia Acorn International		2,600			(2,551	)		(49	)
Columbia Acorn USA		4,809			—			(4,809	)
Columbia Acorn International Select		238			28			(266	)
Columbia Acorn Select		2,193			(589	)		(1,604	)
Columbia Thermostat Fund		—	*		—	*		—

*Represents less than $500.

Net investment income and net realized gains/(losses), as disclosed on the Statements of Operations, and net assets were not affected by these reclassifications.

The tax character of distributions paid during the years ended December 31, 2009 and December 31, 2008 was as follows:

December 31, 2009	Ordinary Income*		Long-Term Capital Gains
(in thousands)
Columbia Acorn Fund	$	20,981	$	—
Columbia Acorn International		60,207		—
Columbia Acorn USA		—		—
Columbia Acorn International Select		3,533		—
Columbia Acorn Select		—		—
Columbia Thermostat Fund		122		—
December 31, 2008	Ordinary Income*		Long-Term Capital Gains
(in thousands)
Columbia Acorn Fund	$	24,585	$	412,506
Columbia Acorn International		32,574		74,297
Columbia Acorn USA		9		53,514
Columbia Acorn International Select		601		4,740
Columbia Acorn Select		—		74,125
Columbia Thermostat Fund		3,595		824

*For tax purposes short-term capital gain distributions, if any, are considered ordinary income distributions.

As of December 31, 2009, the components of distributable earnings on a tax basis were as follows:

	Undistributed Ordinary Income		Undistributed Long-Term Capital Gains		Net Unrealized Appreciation (Depreciation)*
(in thousands)
Columbia Acorn Fund	$	13,908	$	—	$	3,885,370
Columbia Acorn International		78,049		—		1,017,469
Columbia Acorn USA		—		—		284,766
Columbia Acorn International Select		6,032		—		77,602
Columbia Acorn Select		—		—		222,742
Columbia Thermostat Fund		1,276		—		(1,424	)

*The differences between book-basis and tax-basis net unrealized appreciation/(depreciation) are primarily due to deferral of losses from wash sales and PFIC adjustments.

83

Columbia Acorn Family of Funds

Notes to Financial Statements, continued

The following capital loss carryforwards, determined as of December 31, 2009, may be available to reduce taxable income arising from future net realized gains on investments, if any, to the extent permitted by the Internal Revenue Code:

	Year of Expiration
	2010			2011- 2015		2016		2017		Total
(in thousands)
Columbia Acorn Fund	$	—		$	—	$	—	$	409,911	$	409,911
Columbia Acorn International		—			—		135,487		489,443		624,930
Columbia Acorn USA		1,518	*		—		76,008		36,216		113,742
Columbia Acorn International Select		—			—		30,442		46,457		76,899
Columbia Acorn Select		—			—		12,271		115,445		127,716
Columbia Thermostat Fund		—			—		5,193		21,738		26,931

*Remains from Columbia Acorn USA's merger with Stein Roe Small Company Growth Fund on 7/26/2002. Utilization of Stein Roe Small Company Growth Fund's losses could be subject to limitations imposed by the Internal Revenue Code.

Under current tax rules, certain currency and capital losses realized after October 31 may be deferred and treated as occurring on the first day of the following fiscal year. As of December 31, 2009, post-October currency and capital losses attributed to security transactions were deferred to January 1, 2010 as follows:

	Currency		Capital
(in thousands)
Columbia Acorn Fund	$	—	$	6,311
Columbia Acorn International		—		—
Columbia Acorn USA		—		10,041
Columbia Acorn International Select		—		1,985
Columbia Acorn Select		95		—
Columbia Thermostat Fund		—		624

Management is required to determine whether a tax position of the Funds is more likely than not to be sustained upon examination by the applicable taxing authority, including resolution of any related appeals or litigation processes, based on the technical merits of the position. The tax benefit to be recognized by the Funds is measured as the largest amount of benefit that is greater than fifty percent likely of being realized upon ultimate settlement. Management is not aware of any tax positions for which it is reasonably possible that the total amounts of unrecognized tax benefits will significantly change in the next twelve months. However, management's conclusions may be subject to review and adjustment at a later date based on factors including, but not limited to, new tax laws, regulations, and administrative interpretations (including relevant court decisions). The Funds' federal tax returns for the prior three fiscal ye ars remain subject to examination by the Internal Revenue Service.

4.  Transactions with Affiliates

CWAM is a wholly owned subsidiary of Columbia Management, which in turn is an indirect, wholly owned subsidiary of Bank of America Corporation ("BOA"). CWAM furnishes continuing investment supervision to the Funds and is responsible for the overall management of the Funds' business affairs.

Under each Fund's investment advisory agreement, management fees were accrued daily based on each Fund's average daily net assets and paid monthly to CWAM at the annual rates shown in the table below for each Fund.

Columbia Acorn Fund

Average Daily Net Assets	Annual Fee Rate
Up to $700 million		0.74	%
$700 million to $2 billion		0.69	%
$2 billion to $6 billion		0.64	%
$6 billion and over		0.63	%

Columbia Acorn International

Average Daily Net Assets	Annual Fee Rate
Up to $100 million		1.19	%
$100 million to $500 million		0.94	%
$500 million and over		0.74	%

Columbia Acorn USA

Average Daily Net Assets	Annual Fee Rate
Up to $200 million		0.94	%
$200 million to $500 million		0.89	%
$500 million to $2 billion		0.84	%
$2 billion to $3 billion		0.80	%
$3 billion and over		0.70	%

Columbia Acorn International Select

Average Daily Net Assets	Annual Fee Rate
Up to $500 million		0.94	%
$500 million and over		0.90	%

Columbia Acorn Select

Average Daily Net Assets	Annual Fee Rate
Up to $700 million		0.85	%
$700 million to $2 billion		0.80	%
$2 billion to $3 billion		0.75	%
$3 billion and over		0.70	%

Columbia Thermostat Fund

	Annual Fee Rate
All Average Daily Net Assets		0.10	%

84

For the year ended December 31, 2009, the Funds' effective investment advisory fee rates were as follows:

Columbia Acorn Fund	0.65	%
Columbia Acorn International	0.78	%
Columbia Acorn USA	0.87	%
Columbia Acorn International Select	0.94	%
Columbia Acorn Select	0.82	%
Columbia Thermostat Fund	0.10	%

>Expense Limit

CWAM has voluntarily agreed to reimburse the ordinary operating expenses (exclusive of distribution and service fees, brokerage commissions, interest, taxes and extraordinary expenses, but inclusive of custodial charges relating to overdrafts, if any) after giving effect to any balance credits from the Funds' custodian, exceeding 1.45% annually of the average daily net assets for Columbia Acorn International Select and 1.35% annually of the average daily net assets for Columbia Acorn Select. This arrangement may be modified or terminated by either the Funds or CWAM on 30 days notice.

CWAM has contractually agreed to waive fees and/or reimburse expenses of Columbia Thermostat Fund so that the ordinary operating expenses (exclusive of distribution and service fees, interest and fees on borrowings, and expenses associated with the Fund's investment in other investment companies, but including custodian charges relating to overdrafts, if any), after giving effect to any balance credits from the Fund's custodian, will not exceed 0.25% annually of the Fund's average daily net assets through April 30, 2010. There is no guarantee that this arrangement will continue thereafter.

Expenses reimbursed by CWAM to Columbia Acorn International Select and Columbia Thermostat Fund for year ended December 31, 2009, were $4,729 and $326,907, respectively.

CWAM provides administrative services and receives an administration fee from the Funds at the following annual rates:

Columbia Acorn Trust

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

For the year ended December 31, 2009, each Fund's effective administration fee rate was 0.04% of average daily net assets. CWAM has delegated to Columbia Management Advisors, LLC, an indirect, wholly owned subsidiary of BOA, responsibility to provide certain sub-administrative services to the Funds.

Columbia Management Distributors, Inc. ("CMDI"), a wholly owned subsidiary of BOA, is the Funds' principal underwriter.

For the year ended December 31, 2009, Columbia Acorn Fund, Columbia Acorn International, Columbia Acorn USA, Columbia Acorn International Select, Columbia Acorn Select and Columbia Thermostat Fund have been advised that CMDI retained $315,299 in underwriting discounts in connection with redemptions of Class A shares and received CDSCs of $1,896, $536,401 and $45,651, in connection with Class A, Class B and Class C share redemptions, respectively.

Each Fund has adopted a Rule 12b-1 (distribution and service) plan which requires it to pay CMDI a monthly service fee equal to 0.25% annually of the average daily net assets attributable to Class A, Class B and Class C shares and a monthly distribution fee equal to 0.50% and 0.75%, annually, of the average daily net assets attributable to Class B and Class C shares, respectively. CMDI receives no compensation with respect to Class Z shares.

Columbia Management Services, Inc. (the "Transfer Agent"), an indirect, wholly owned subsidiary of BOA, provides shareholder services to the Funds. For such services, each Fund pays the Transfer Agent a monthly fee at the annual rate of $17.00 per account. The Transfer Agent also receives reimbursement for certain out-of-pocket expenses and sub-transfer agency expenses.

Certain officers and trustees of the Trust are also officers of CWAM. The Trust makes no direct payments to its officers and trustees who are affiliated with CWAM.

The Board of Trustees appointed a Chief Compliance Officer to the Trust in accordance with federal securities regulations. The Funds, along with other affiliated funds, pay their pro-rata share of the expenses associated with the Office of the Chief Compliance Officer. Those expenses are disclosed separately as "Chief compliance officer expenses" in the Statements of Operations.

The Trust offers a deferred compensation plan for its independent trustees. Under that plan, a trustee may elect to defer all or a portion of his or her compensation. Amounts deferred are retained by the Trust and may represent an unfunded obligation of the Trust. The value of amounts deferred is determined by reference to the change in value of Class Z shares of one or more series of the Trust or a money market fund specified by the trustee. Benefits under the deferred compensation plan are payable when the trustee ceases to be a member of the Board of Trustees.

85

Columbia Acorn Family of Funds

Notes to Financial Statements, continued

An affiliated person of a Fund may include any company in which a Fund owns five percent or more of its outstanding voting shares. On December 31, 2009, Columbia Acorn Fund, Columbia Acorn International, Columbia Acorn USA and Columbia Acorn Select each held five percent or more of the outstanding voting securities of one or more companies. Details of investments in those affiliated companies are presented on pages 31, 32, 41, 52 and 63, respectively.

During the year ended December 31, 2009, the Funds engaged in purchase and sale transactions with funds that have a common investment advisor (or affiliated investment advisors), common directors/trustees, and/or common officers. Those transactions complied with Rule 17a-7 under the Investment Company Act of 1940 and were as follows:

	Purchases		Sales
(in thousands)
Columbia Acorn International	$	7,422	$	—
Columbia Acorn Select		—		1,655

5.  Objectives and Strategies for Investing in Derivative Instruments

Columbia Acorn International uses derivatives instruments including forward foreign currency exchange contracts in order to meet its investment objectives. The Fund employs strategies in differing combinations to permit it to increase, decrease or change the level of exposure to market risk factors. The achievement of any strategy involving derivatives depends on analysis of various risk factors, and if the strategies for the use of derivatives do not work as intended, the Fund may not achieve its investment objectives.

In pursuit of its investment objectives, the Fund is exposed to the following market risk:

Foreign Exchange Rate Risk: Foreign exchange rate risk relates to the change in the U.S. dollar value of a security held that is denominated in a foreign currency. The U.S. dollar value of a foreign-currency-denominated security will decrease as the dollar appreciates against the currency, while the U.S. dollar value will increase as the dollar depreciates against the currency.

The following notes provide more detailed information about the derivative type held by the Columbia Acorn International:

Forward Foreign Currency Exchange Contracts

• The Fund entered into forward foreign currency exchange contracts to shift its investment exposure from one currency to another.

• The Fund used forward foreign currency exchange contracts to shift its U.S. dollar exposure in order to achieve a representative weighted mix of major currencies relative to its benchmark and/or to recover an underweight country exposure in its portfolio relative to its benchmark.

Forward foreign currency exchange contracts are agreements to exchange one currency for another at a future date at a specified price. These contracts are used to minimize the exposure to foreign exchange rate fluctuations during the period between the trade and settlement dates of the contract. The Fund may utilize forward foreign currency exchange contracts in connection with the settlement of purchases and sales of securities. The Fund may also enter into these contracts to reduce the exposure to adverse price movements in certain other foreign-currency-denominated assets. Contracts to buy are used to acquire exposure to foreign currencies, while contracts to sell are used to reduce the exposure to foreign exchange rate fluctuations. Forward foreign currency exchange contracts are valued daily at the current exchange rate of the underlying currency, resulting in unrealized gains (losses) which become realized at the time the forward foreign currency exchange contracts are closed or mature. Realized and unrealized gains (losses) arising from such transactions are included in net realized and unrealized gains (losses) on foreign currency transactions. The use of forward foreign currency exchange contracts does not eliminate fluctuations in the prices of the Fund's portfolio securities. While the maximum potential loss from such contracts is the aggregate face value in U.S. dollars at the time the contract was opened, exposure is typically limited to the change in value of the contract (in U.S. dollars) over the period it remains open. The Fund could also be exposed to risk that counterparties of the contracts may be unable to fulfill the terms of the contracts.

During the year ended December 31, 2009, Columbia Acorn International entered into 122 forward foreign currency exchange contracts.

The following table is a summary of the value of the Columbia Acorn International's derivative instruments as of December 31, 2009.

  Fair Value of Derivative Instruments

	Asset
	Statement of Assets and Liabilities	Fair Value
(in thousands)
	Unrealized appreciation on forward foreign currency exchange contracts	$	6,689

86

	Liability
	Statement of Assets and Liabilities	Fair Value
(in thousands)
	Unrealized depreciation on forward foreign currency exchange contracts	$	(4,205	)

The effect of derivative instruments on the Columbia Acorn International's Statement of Operations for the year ended December 31, 2009 was as follows:

Amount of Realized Gain or (Loss) and Change in Unrealized Appreciation or (Depreciation)
on Derivatives Recognized in Income

	Risk Exposure	Realized Gain/(Loss)		Change in Unrealized Appreciation/ (Depreciation)
(in thousands)
Forward foreign currency exchange contracts	Foreign Exchange Rate Risk	$	4,507	$	5,763

6.  Borrowing Arrangements

The Trust participated in a $150 million credit facility, along with another Trust managed by CWAM, which was entered into to facilitate portfolio liquidity. Under the facility, interest is charged to each participating fund based on its borrowings at a rate per annum equal to the higher of Federal Funds Rate or Overnight LIBOR plus 0.75%. In addition, a commitment fee of 0.12% per annum of the unutilized line of credit was accrued and apportioned among the participating funds based on their relative net assets. The commitment fee is included in "Other expenses" in the Statements of Operations. No amounts were borrowed by any Fund under this facility for the year ended December 31, 2009. The Trust enters into this line of credit for one year durations. The Trust has secured the line of credit for the entire year of 2010.

7.  Investment Transactions

The aggregate cost of purchases and proceeds from sales, other than short-term obligations, for the year ended December 31, 2009, were:

Columbia Acorn Fund

(in thousands)
Investment securities
Purchases	$	3,110,424
Proceeds from sales		3,561,995

Columbia Acorn International

(in thousands)
Investment securities
Purchases	$	1,154,358
Proceeds from sales		1,014,864

Columbia Acorn USA

(in thousands)
Investment securities
Purchases	$	355,188
Proceeds from sales		305,733

Columbia Acorn International Select

(in thousands)
Investment securities
Purchases	$	233,777
Proceeds from sales		170,251

Columbia Acorn Select

(in thousands)
Investment securities
Purchases	$	280,494
Proceeds from sales		568,076

Columbia Thermostat Fund

(in thousands)
Investment securities
Purchases	$	22,134
Proceeds from sales		56,558

8.  Redemption Fees

For the year ended December 31, 2009, the redemption fees imposed by Columbia Acorn International and Columbia Acorn International Select amounted to approximately $259,441 and $33,449, respectively, and are accounted for as additions to paid in capital.

9.  Regulatory Settlements with Third Parties

During the year ended December 31, 2009, Columbia Acorn Fund, Columbia Acorn International, Columbia Acorn USA and Columbia Acorn International Select received payments totaling $39,819, $1,210,287, $4,593 and $265,461, respectively, representing distributions from a fair fund established in connection with a regulatory settlement between the Securities and Exchange Commission and a third party broker dealer relating to alleged market timing and late trading in mutual funds, including the Funds. The payments have been included in "Increase from regulatory settlements" on the Statements of Changes in Net Assets.

10.  Legal Proceedings

The Trust, CWAM and the Trustees of the Trust (collectively, the "Columbia defendants") are named as defendants in class and derivative complaints that have been consolidated in a Multi-District Action (the "MDL Action") in the federal district court of Maryland. These lawsuits contend that defendants permitted certain investors to market time their trades in certain Columbia Acorn Funds. The MDL Action is ongoing.

87

Columbia Acorn Family of Funds

Notes to Financial Statement, continued

However, all claims against the Trust and the independent trustees of the Trust have been dismissed.

The Trust and CWAM are also defendants in a class action lawsuit that alleges, in summary, that the Trust and CWAM exposed shareholders of Columbia Acorn International Fund to trading by market timers by allegedly: (a) failing to properly evaluate daily whether a significant event affecting the value of the Fund's securities had occurred after foreign markets had closed but before the calculation of the Fund's net asset value ("NAV"); (b) failing to implement the Fund's portfolio valuation and share pricing policies and procedures; and (c) failing to know and implement applicable rules and regulations concerning the calculation of NAV (the "Fair Valuation Lawsuit"). The Seventh Circuit ruled that the plaintiffs' state law claims were preempted under federal law resulting in the dismissal of plaintiffs' complaint. Plaintiffs appealed the Seventh Circuit's ruling to the United States Supreme Court. The Supreme Court reversed the S eventh Circuit's ruling on jurisdictional grounds and the case was ultimately remanded to the state court.

On March 21, 2005, a class action complaint was filed against the Trust and CWAM seeking to rescind the CDSC assessed upon redemption of Class B shares of Columbia Acorn Funds due to the alleged market timing of the Columbia Acorn Funds (the "CDSC Lawsuit"). In addition to the rescission of sales charges, plaintiffs seek recovery of actual damages, attorneys' fees and costs. The case had been transferred to the MDL Action in the federal district court of Maryland.

On September 14, 2007, the plaintiffs and the Columbia defendants named in the MDL Action, including the Columbia Funds, entered into a stipulation of settlement with respect to all Columbia-related claims in the MDL Action described above, including the CDSC and Fair Valuation Lawsuits. The settlement is subject to court approval.

Columbia Acorn Trust and CWAM intend to defend these suits vigorously.

CWAM believes that the lawsuits are not likely to materially affect its ability to provide investment management services to the Funds.

88

Report of Independent Registered Public Accounting Firm

To the Board of Trustees and Shareholders of
Columbia Acorn Trust:

In our opinion, the accompanying statement of assets and liabilities, including the schedule of investments, and the related statements of operations and of changes in net assets and the financial highlights present fairly, in all material respects, the financial position of Columbia Acorn Fund, Columbia Acorn International, Columbia Acorn USA, Columbia Acorn International Select, Columbia Acorn Select and Columbia Thermostat Fund (each a series of the Columbia Acorn Trust, hereinafter referred to as the "Funds") at December 31, 2009, the results of its operations for the year then ended, the changes in its net assets for each of the two years in the period then ended and the financial highlights for each of the five years in the period then ended, in conformity with accounting principles generally accepted in the United States of America. These financial statements and financial highlights (hereafter referred to as "financial s tatements") are the responsibility of the Funds' management; our responsibility is to express an opinion on these financial statements based on our audits. We conducted our audits of these financial statements in accordance with the standards of the Public Company Accounting Oversight Board (United States). Those standards require that we plan and perform the audit to obtain reasonable assurance about whether the financial statements are free of material misstatement. An audit includes examining, on a test basis, evidence supporting the amounts and disclosures in the financial statements, assessing the accounting principles used and significant estimates made by management, and evaluating the overall financial statement presentation. We believe that our audits, which included confirmation of securities at December 31, 2009 by correspondence with the custodian and brokers, provide a reasonable basis for our opinion.

PricewaterhouseCoopers LLP
Chicago, Illinois
February 18, 2010

89

Columbia Acorn Family of Funds

Federal Income Tax Information (in thousands) (unaudited) — Class A, B, C and Z shares

Columbia Acorn Fund

100.00% of the ordinary income distributed by the Fund, for the fiscal year ended December 31, 2009 qualified for the corporate dividends received deduction.

For non-corporate shareholders 100.00%, or the maximum amount allowable under the Jobs and Growth Tax Relief Reconciliation Act of 2003, of ordinary income distributed by the Fund for the fiscal year ended December 31, 2009 may represent qualified dividend income.

Columbia Acorn International

Foreign taxes paid during the fiscal year ended December 31, 2009, of $6,483 are being passed through to shareholders. This represents $0.05 per share. Eligible shareholders may claim this amount as a foreign tax credit.

Gross income derived from sources within foreign countries was $81,906 ($0.63 per share) for the fiscal year ended December 31, 2009.

For non-corporate shareholders 82.95%, or the maximum amount allowable under the Jobs and Growth Tax Relief Reconciliation Act of 2003, of ordinary income distributed by the Fund for the fiscal year ended December 31, 2009 may represent qualified dividend income.

Columbia Acorn International Select

Foreign taxes paid during the fiscal year ended December 31, 2009, of $521 are being passed through to shareholders. This represents $0.03 per share. Eligible shareholders may claim this amount as a foreign tax credit.

Gross income derived from sources within foreign countries was $6,377 ($0.37 per share) for the fiscal year ended December 31, 2009.

13.08% of the ordinary income distributed by the Fund, for the fiscal year ended December 31, 2009 qualified for the corporate dividends received deduction.

For non-corporate shareholders 100.00%, or the maximum amount allowable under the Jobs and Growth Tax Relief Reconciliation Act of 2003, of ordinary income distributed by the Fund for the fiscal year ended December 31, 2009 may represent qualified dividend income.

Columbia Thermostat Fund

100.00% of the ordinary income distributed by the Fund for the fiscal year ended December 31, 2009, qualifies for the corporate dividends received deduction.

For non-corporate shareholders, 100.00% or the maximum amount allowable under the Jobs and Growth Tax Relief Reconciliation Act of 2003, of the ordinary income distributed by the Fund for the fiscal year ended December 31, 2009 may represent qualified dividend income.

90

Board of Trustees and Management of
Columbia Acorn Funds

Each trustee may serve a term of unlimited duration. The Trust's By-laws generally require that a trustee retire at the end of the calendar year in which the trustee attains the age of 75 years. The trustees appoint their own successors, provided that at least two-thirds of the trustees, after such appointment, have been elected by shareholders. Shareholders may remove a trustee, with or without cause, upon the vote of two-thirds of the Trust's outstanding shares at any meeting called for that purpose. A trustee may be removed, with or without cause, upon the vote of a majority of the trustees. The names of the trustees and officers of the Trust, the date each was first elected or appointed to office, their principal business occupations during at least the last five years, number of portfolios in the fund complex they oversee, and other directorships they hold, are shown below. Each trustee serves in such capacity for each of t he six series of Columbia Acorn Trust and for each of the four series of Wanger Advisors Trust.

The address for the trustees and officers of the Trust is Columbia Wanger Asset Management, L.P., 227 West Monroe Street, Suite 3000, Chicago, Illinois 60606. The Funds' Statement of Additional Information includes additional information about the Funds' trustees and officers. You may obtain a free copy of the Statement of Additional Information by writing or calling toll-free:

Columbia Wanger Asset Management, L.P.
Shareholder Services Group
227 W. Monroe, Suite 3000
Chicago IL 60606
1-800-922-6769

Name, Position(s) with Columbia Acorn Trust and Age at December 31, 2009	Year First Elected or Appointed to Office*		Principal Occupation(s) during Past Five Years	Number of Portfolios in Fund Complex Overseen by Trustee/Officer		Other Directorships in addition to Columbia Acorn Trust
Trustees who are not interested persons of Columbia Acorn Trust:
Laura M. Born, 44, Trustee		2007	Adjunct Assistant Professor of Finance, University of Chicago Booth School of Business; formerly, Managing Director – Investment Banking, J.P. Morgan Chase & Co. (broker/dealer) 2002-2007.		10	Wanger Advisors Trust
Michelle L. Collins, 49, Trustee		2008	President, Cambium LLC (financial advisory firm) since 2007; Advisory Board Member, Svoboda Capital Partners LLC (private equity firm) since 2007; Managing Director Svoboda Capital Partners LLC, 1998-2006.		10	Wanger Advisors Trust; Bucyrus International, Inc. (mining equipment manufacturer); Molex, Inc. (electronics components manufacturer).
Maureen M. Culhane, 61, Trustee		2007	Retired. Formerly, Vice President, Goldman Sachs Asset Management, L.P. (investment advisor), 2005-2007, and Vice President (Consultant) – Strategic Relationship Management, Goldman Sachs AG, 1999-2005.		10	Wanger Advisors Trust
Margaret M. Eisen, 56, Trustee		2002	Chief Investment Officer, EAM International LLC (corporate finance and asset management) since 2003; Managing Director, CFA Institute, 2005-2008.		10	Wanger Advisors Trust; Antigenics, Inc. (biotechnology and pharmaceuticals) (until June 2009).
Jerome Kahn, Jr., 75,(1) Trustee		1987	Portfolio manager and stock analyst; formerly, President, William Harris Investors, Inc. (investment advisor).		10	Wanger Advisors Trust
Steven N. Kaplan, 50, Trustee and Vice Chairman of the Board		1999	Neubauer Family Professor of Entrepreneurship and Finance, University of Chicago Booth School of Business.		10	Wanger Advisors Trust; Accretive Health, Inc. (healthcare management services provider); Morningstar, Inc. (provider of independent investment research).
David C. Kleinman, 74, Trustee		1972	Adjunct Professor of Strategic Management, University of Chicago Booth School of Business; business consultant.		10	Wanger Advisors Trust; Sonic Foundry, Inc. (rich media systems and software).
Allan B. Muchin, 73, Trustee		1998	Chairman Emeritus, Katten Muchin Rosenman LLP (law firm).		10	Wanger Advisors Trust

91

Name, Position(s) with Columbia Acorn Trust and Age at December 31, 2009	Year First Elected or Appointed to Office*		Principal Occupation(s) during Past Five Years	Number of Portfolios in Fund Complex Overseen by Trustee/Officer		Other Directorships in addition to Columbia Acorn Trust
Trustees who are not interested persons of Columbia Acorn Trust: (continued)
James A. Star, 48, Trustee and Chairman of the Board		2006	President, Longview Asset Management LLC (investment advisor) since 2003; Director, Traush Industries (privately-owned manufacturer of refrigeration parts and products).		10	Wanger Advisors Trust
John A. Wing, 74, Trustee		2002	Partner, Dancing Lion Partners (investment firm); prior thereto, Frank Wakely Gunsaulus Professor of Law and Finance and Chairman of the Center for the Study of Law and Financial Markets, Illinois Institute of Technology; formerly, Chairman of the Board and Chief Executive Officer, ABN-AMRO Inc. (formerly named The Chicago Corporation, a financial services firm) and Chief Executive Officer, Market Liquidity Network, LLC.		10	Wanger Advisors Trust; First Chicago Bank and Trust; First Chicago Bancorp.
Trustees who are interested persons of Columbia Acorn Trust:
Charles P. McQuaid, 56, Trustee and President(2)		1992	President and Chief Investment Officer, CWAM or its predecessors, since October 2003; associated with CWAM or its predecessors since 1978.		10	Wanger Advisors Trust
Ralph Wanger, 75, Trustee(3)		1970	Founder, CWAM. Formerly, President, Chief Investment Officer and portfolio manager, CWAM or its predecessors, July 1992 – September 2003; Director, Wanger Investment Company PLC; Consultant, CWAM or its predecessors, September 2003 – September 2005.		10	Wanger Advisors Trust
Officers of Columbia Acorn Trust:
Ben Andrews, 43, Vice President		2004	Portfolio manager and analyst, CWAM or its predecessors, since 1998; Vice President, Columbia Acorn Trust and Wanger Advisors Trust since 2004.		10	None
Michael G. Clarke, 40, Assistant Treasurer		2004	Senior Vice President and Chief Financial Officer of certain Columbia Funds since January 2009; Treasurer of certain Columbia Funds from June 2008 – January 2009; Deputy Treasurer of certain Columbia Funds since June 2008; Chief Accounting Officer and Assistant Treasurer, the Columbia Funds, October 2004 to May 2008; Director of Fund Administration, Columbia Management Advisors, LLC, since January 2006; Managing Director, Columbia Management Advisors, LLC, September 2004 – December 2005.		10	None
Jeffrey Coleman, 40, Assistant Treasurer		2006	Treasurer of certain Columbia Funds since June 2008; Director of Fund Administration, CWAM, since January 2006; Fund Controller, CWAM or its predecessors, October 2004 – January 2006.		10	None
P. Zachary Egan, 41, Vice President		2003	Director of International Research, CWAM or its predecessors, since December 2004; Vice President, Columbia Acorn Trust since 2003 and Wanger Advisors Trust since 2007; portfolio manager and analyst, CWAM or its predecessors, since 1999.		10	None
Peter T. Fariel, 52, Assistant Secretary		2006	Associate General Counsel, Bank of America Corporation, since April 2005; prior thereto, Partner, Goodwin Procter LLP (law firm).		10	None

92

Name, Position(s) with Columbia Acorn Trust and Age at December 31, 2009	Year First Elected or Appointed to Office*		Principal Occupation(s) during Past Five Years	Number of Portfolios in Fund Complex Overseen by Trustee/Officer		Other Directorships in addition to Columbia Acorn Trust
Officers of Columbia Acorn Trust: (continued)
John Kunka, 39, Assistant Treasurer		2006	Director of Accounting and Operations, CWAM or its predecessors, since May 2006; Manager of Mutual Fund Operations, Calamos Advisors, Inc. (investment advisor), September 2005 – May 2006; prior thereto, Manager of Mutual Fund Administration, Van Kampen Investments.		10	None
Joseph C. LaPalm, 40, Vice President		2006	Chief Compliance Officer, CWAM since 2005; prior thereto, compliance officer, William Blair & Company (investment firm).		10	None
Bruce H. Lauer, 52, Vice President, Secretary and Treasurer		1995	Chief Operating Officer, CWAM or its predecessors, since April 2000; Vice President, Secretary and Treasurer, Columbia Acorn Trust and Wanger Advisors Trust, since 1995; Director, Wanger Investment Company PLC; Director, Banc of America Capital Management (Ireland) Ltd.; Director, Bank of America Global Liquidity Funds, PLC.		10	None
Louis J. Mendes III, 45, Vice President		2003	Portfolio manager and analyst, CWAM or its predecessors, since 2001; Vice President, Columbia Acorn Trust since 2003 and Wanger Advisors Trust since 2005.		10	None
Robert A. Mohn, 48, Vice President		1997	Director of Domestic Research, CWAM or its predecessors, since March 2004; Vice President, Columbia Acorn Trust and Wanger Advisors Trust, since 1997; portfolio manager and analyst, CWAM or its predecessors, since August 1992.		10	None
Christopher J. Olson, 45, Vice President		2001	Portfolio manager and analyst, CWAM or its predecessors, since January 2001; Vice President, Columbia Acorn Trust and Wanger Advisors Trust, since 2001.		10	None
Robert P. Scales, 57, Chief Compliance Officer, Chief Legal Officer, Senior Vice President and General Counsel		2004	Chief Compliance Officer, Chief Legal Officer, Senior Vice President and General Counsel, Columbia Acorn Trust and Wanger Advisors Trust, since 2004.		10	None
Linda Roth-Wiszowaty, 40, Assistant Secretary		2006	Business support analyst, CWAM, since April 2007; prior thereto executive administrator, CWAM or its predecessors, and executive assistant to the Chief Operating Officer of CWAM or its predecessors.		10	None

*  Dates prior to April 1992 correspond to the date of first election or appointment as a trustee or officers of The Acorn Fund, Inc., the predecessor trust to Columbia Acorn Trust.

(1)  Mr. Kahn retired at the end of calendar year 2009.

(2)  Mr. McQuaid is an "interested person" of Columbia Acorn Trust and of CWAM, as defined in the Investment Company Act of 1940 because he is an officer of the Trust and of CWAM.

(3)  Mr. Wanger is an "interested person" of Columbia Acorn Trust and of CWAM, as defined in the Investment Company Act of 1940 because, as of December 31, 2009, he owned securities issued by a controlling person of CWAM and was a consultant to CWAM within the most recently completed five fiscal years.

93

Columbia Acorn Family of Funds

Fourth Quarter Class A, B and C Share Information

Minimum Initial Investment in all Funds	$2,500 $1,000 for an IRA
Minimum Subsequent Investment in all Funds	$50
Exchange Fee	None

Columbia Acorn Fund	Class A			Class B*			Class C
Management Fees		0.65	%		0.65	%		0.65	%
Distribution and Service (12b-1) Fees		0.25	%		0.75	%		1.00	%
Other Expenses		0.17	%		0.34	%		0.24	%
Net Expense Ratio		1.07	%		1.74	%		1.89	%
Columbia Acorn International	Class A			Class B*			Class C
Management Fees		0.78	%		0.78	%		0.78	%
Distribution and Service (12b-1) Fees		0.25	%		0.75	%		1.00	%
Other Expenses		0.33	%		0.50	%		0.39	%
Net Expense Ratio		1.36	%		2.03	%		2.17	%
Columbia Acorn USA	Class A			Class B*			Class C
Management Fees		0.87	%		0.87	%		0.87	%
Distribution and Service (12b-1) Fees		0.25	%		0.75	%		1.00	%
Other Expenses		0.20	%		0.40	%		0.26	%
Net Expense Ratio		1.32	%		2.02	%		2.13	%
Columbia Acorn International Select	Class A			Class B*			Class C
Management Fees		0.94	%		0.94	%		0.94	%
Distribution and Service (12b-1) Fees		0.25	%		0.75	%		1.00	%
Other Expenses		0.38	%		0.51	%		0.48	%
Net Expense Ratio		1.57	%		2.20	%		2.42	%
Columbia Acorn Select	Class A			Class B*			Class C
Management Fees		0.82	%		0.82	%		0.82	%
Distribution and Service (12b-1) Fees		0.25	%		0.75	%		1.00	%
Other Expenses		0.23	%		0.44	%		0.32	%
Net Expense Ratio		1.30	%		2.01	%		2.14	%
Columbia Thermostat Fund	Class A			Class B*			Class C
Management Fees		0.10	%		0.10	%		0.10	%
Distribution and Service (12b-1) Fees		0.25	%		0.75	%		1.00	%
Other Expenses**		0.15	%		0.15	%		0.15	%
Net Expense Ratio		0.50	%		1.00	%		1.25	%

    Fees and expenses are for the twelve months ended December 31, 2009. Some share classes of Columbia Acorn Select and Columbia Acorn International Select Funds include the effect of CWAM's voluntary undertaking to waive fees and/or reimburse the Funds for any ordinary operating expenses (exclusive of distribution and service fees, brokerage commissions, interest, taxes and extraordinary expenses, but inclusive of custodian charges relating to overdrafts, if any), after giving effect to any balance credits from the Funds' custodian, in excess of the annual rate of 1.35% and 1.45%, respectively, of the average daily net assets. These arrangements may be modified or terminated by either the Funds or CWAM upon 30 days notice. Columbia Thermostat Fund's fees and expenses include the effect of CWAM's contractual undertaking to waive fees and/or reimburse the Fund for any ordinary operating expenses (exclusive of distribution and service fees, interest and fees on borrowings, and expenses associated with the Fund's investment in other investment companies, but including custodian charges relating to overdrafts, if any), after giving effect to any balance credits from the Fund's custodian, in excess of the annual rate of 0.25% of the average daily net assets. Columbia Thermostat Fund's reimbursement arrangement is contractual through April 30, 2010. There is no guarantee that this arrangement will continue thereafter.

  *  The Funds no longer offer Class B shares (other than through dividend reinvestment).

  **  Does not include estimated fees and expenses of 0.82% incurred by the Fund from the underlying portfolio funds in which it invests.

94

Columbia Acorn Family of Funds

Investment Advisor

Columbia Wanger Asset Management, L.P.
227 West Monroe Street, Suite 3000
Chicago, Illinois 60606

1-800-922-6769

Distributor

Columbia Management Distributors, Inc.
One Financial Center
Boston, Massachusetts 02111-2621

Transfer Agent, Dividend Disbursing Agent

Columbia Management Services, Inc.
P. O. Box 8081
Boston, Massachusetts 02266-8081

1-800-345-6611

Legal Counsel to the Funds

K&L Gates LLP
Washington, DC

Legal Counsel to the Independent Trustees

Drinker Biddle & Reath LLP
Philadelphia, Pennsylvania

Independent Registered Public Accounting Firm

PricewaterhouseCoopers LLP
Chicago, Illinois

This report, including the schedules of investments, is submitted for the general information of the shareholders of Columbia Acorn Trust.

A description of the policies and procedures that the Funds use to determine how to vote proxies and a copy of the Funds' voting record are available (i) without charge, upon request, by calling 800-922-6769 and (ii) on the Securities and Exchange Commission's website at www.sec.gov. Information regarding how the Funds voted proxies relating to portfolio securities during the 12-month period ended June 30, 2009, is available from the SEC's website. Information regarding how the Funds voted proxies relating to portfolio securities is also available at http://institutional.columbiamanagement.com.

The Funds file a complete schedule of portfolio holdings with the SEC for the first and third quarters of each fiscal year on Form N-Q. The Funds' Form N-Q is available on the SEC's website at www.sec.gov and may be reviewed and copied at the SEC's Public Reference Room in Washington, D.C. Information on the operation of the Public Reference Room may be obtained by calling 1-800-SEC-0330. The Funds' complete portfolio holdings are disclosed at www.columbiafunds.com, approximately 30 days after each month-end.

Please read and consider the investment objectives, risks, charges and expenses for any fund carefully before investing. For a prospectus which contains this and other important information about the Fund, contact your Columbia Management representative or financial advisor or go to www.columbiamanagement.com.

Columbia Management Group, LLC ("Columbia Management") is the investment management division of Bank of America Corporation. Columbia Management entities furnish investment management services and products for institutional and individual investors. Columbia Funds are distributed by Columbia Management Distributors, Inc., member of FINRA, SIPC, part of Columbia Management and an affiliate of Bank of America Corporation.

Columbia Wanger Asset Management, L.P. ("CWAM") is a registered investment advisor and an indirect, wholly owned subsidiary of Bank of America Corporation. CWAM is part of Columbia Management.

Find out what's new – visit our web site at:

www.columbiafunds.com

Our e-mail address is:

ServiceInquiries@ColumbiaManagement.com

Shareholders should not include personal information such as account numbers, Social Security numbers or taxpayer identification numbers in e-mail. We are unable to accept account transactions sent via e-mail.

PRESORTED

FIRST-CLASS MAIL

U.S. POSTAGE PAID

HOLLISTON, MA

PERMIT NO. 20

Columbia Management^®

Columbia Acorn Family of Funds

Class A, B and C Shares

Annual Report, December 31, 2009

For More Information

You'll find more information about the Columbia Acorn Family Funds in the documents described below. Contact Columbia Funds as follows to obtain these documents free of charge:

By Mail:  Columbia Funds
c/o Columbia Management Services, Inc.
P.O. Box 8081
Boston, MA 02266-8081

By Telephone: 800.345.6611

Online: www.columbiafunds.com

Shareholder Communications with the Board

The Funds' Board of Trustees has adopted procedures by which shareholders may communicate with the Board. Shareholders who wish to communicate with the Board should send their written communications to the Board by mail, c/o Columbia Wanger Asset Management, L.P., 227 West Monroe Street, Suite 3000, Chicago, Illinois 60606, Attention: Secretary. Shareholder communications must (i)be in writing, (ii) identify the Columbia Acorn Fund to which the communication relates and (iii) state the particular class of shares and number of shares held by the communicating shareholder.

Prospectuses and the Statement of Additional Information (SAI)

The prospectuses and the SAI provide more detailed information about the Funds and their policies. The SAI is legally part of each prospectus (it's incorporated by reference). A copy of each has been filed with the SEC.

Information Provided by the SEC

You can review and copy information about the Funds (including their prospectuses, the SAI and shareholder reports) at the SEC's Public Reference Room in Washington, DC. To find out more about the operation of the Public Reference Room, call the SEC at 202.551.8090. Reports and other information about the Fund are also available in the EDGAR Database on the SEC's website at http://www.sec.gov, or you can receive copies of this information, for a fee, by electronic request at the following e-mail address: publicinfo@sec.gov. You can also obtain copies of this information by writing the Public Reference Section, Securities and Exchange Commission, Washington, DC 20549-0102.

The investment company registration number of Columbia Acorn Trust, of which each of these Funds are a series, is 811-01829.

© 2010 Columbia Management Distributors, Inc.

One Financial Center, Boston, MA 02111-2621

800.345.6611 www.columbiamanagement.com

SHC-42/30133 1209 10/D6A5X0

Item 2. Code of Ethics.

(a)The registrant has, as of the end of the period covered by this report, adopted a code of ethics that applies to the registrant’s principal executive officer, principal financial officer, principal accounting officer or controller, or persons performing similar functions, regardless of whether these individuals are employed by the registrant or a third party.

(b)During the period covered by this report, there were not any amendments to a provision of the code of ethics adopted in 2(a) above.

(c)During the period covered by this report, there were no waivers, including any implicit waivers, from a provision of the code of ethics described in 2(a) above that relates to one or more of the items set forth in paragraph (b) of this item’s instructions.

Item 3. Audit Committee Financial Expert.

The registrant’s Board of Trustees has determined that Laura M. Born, Michelle L. Collins and David C. Kleinman, each of whom are members of the registrant’s Board of Trustees and Audit Committee, each qualify as an audit committee financial expert.  Ms. Born, Ms. Collins and Mr. Kleinman are each independent trustees, as defined in paragraph (a)(2) of this item’s instructions.

Item 4. Principal Accountant Fees and Services.

(a) Audit Fees. Aggregate Audit Fees billed by the principal accountant for professional services rendered during the fiscal years ended December 31, 2009 and December 31, 2008 are approximately as follows:

2009		2008
$	215,300	$	215,300

Audit Fees include amounts related to the audit of the registrant’s annual financial statements or services that are normally provided by the accountant in connection with statutory and regulatory filings or engagements for those fiscal years.

(b) Audit-Related Fees. Aggregate Audit-Related Fees billed to the registrant by the principal accountant for professional services rendered during the fiscal years ended December 31, 2009 and December 31, 2008 are approximately as follows:

2009		2008
$	11,000	$	41,000

Audit-Related Fees include amounts for assurance and related services by the principal accountant that are reasonably related to the performance of the audit of the registrant’s financial statements and are not reported in Audit Fees above.  In fiscal years 2009 and 2008, Audit-Related Fees consist of agreed-upon procedures performed for other audit-related additional testing.

During the fiscal years ended December 31, 2009 and December 31, 2008, there were no Audit-Related Fees billed by the registrant’s principal accountant to the registrant’s investment adviser (not including any sub-adviser whose role is primarily portfolio management and is subcontracted with or overseen by another investment adviser) and any entity controlling, controlled by, or under common control with the adviser that provides ongoing services to the registrant for an engagement that related directly to the operations and financial reporting of the registrant.

(c) Tax Fees. Aggregate Tax Fees billed by the principal accountant to the registrant for professional services rendered during the fiscal years ended December 31, 2009 and December 31, 2008 are approximately as follows:

2009		2008
$	40,600	$	41,400

Tax Fees incurred in both fiscal years 2009 and 2008 relate to the review of annual tax returns, the review of required shareholder distribution calculations and include amounts for professional services by the principal accountant for tax compliance, tax advice and tax planning.

During the fiscal years ended December 31, 2009 and December 31, 2008, there were no Tax Fees billed by the registrant’s principal accountant to the registrant’s investment adviser (not including any sub-adviser whose role is primarily portfolio management and is subcontracted with or overseen by another investment adviser) and any entity controlling, controlled by, or under common control with the adviser that provides ongoing services to the registrant for an engagement that related directly to the operations and financial reporting of the registrant.

(d) All Other Fees. Aggregate All Other Fees billed by the principal accountant to the registrant for professional services rendered during the fiscal years ended December 31, 2009 and December 31, 2008 are as follows:

2009		2008
$	0	$	0

All Other Fees include amounts for products and services provided by the principal accountant, other than the services reported in paragraphs (a) through (c) above.

Aggregate All Other Fees billed by the registrant’s principal accountant to the registrant’s investment adviser (not including any sub-adviser whose role is primarily portfolio management and is subcontracted with or overseen by another investment adviser) and any entity controlling, controlled by, or under common control with the adviser that provides ongoing services to the registrant for an engagement that related directly to the operations and financial reporting of the registrant during the fiscal years ended December 31, 2009 and December 31, 2008 are approximately as follows:

2009		2008
$	67,900	$	136,100

In both fiscal years 2009 and 2008, All Other Fees consist of professional services rendered for internal control reviews of the registrant’s transfer agent.

(e)(1) Audit Committee Pre-Approval Policies and Procedures

The policy of the registrant’s Audit Committee is to specifically pre-approve (i) all audit and non-audit (including audit related, tax and all other) services provided by the registrant’s independent auditor to the registrant and individual funds (collectively “Fund Services”) and (ii) all non-audit services provided by the registrant’s independent auditor to the funds’ adviser or a control affiliate of the adviser, that relate directly to the funds’ operations and financial reporting (collectively “Fund-related Adviser Services”).  A “control affiliate” is an entity controlling, controlled by, or under common control with the adviser that provides ongoing services to the funds, and the term “adviser” is deemed to exclude any unaffiliated sub-adviser whose role is primarily portfolio management and is sub-contracted or overseen by another investment adviser.

If such Fund Services or Fund-related Adviser Services are required during the period between the Audit Committee’s regularly scheduled meetings, the Chairman of the Audit Committee has the authority to pre-approve the service, with reporting to the full Audit Committee at the next regularly scheduled meeting.

The Audit Committee will waive pre-approval of Fund Services or Fund-related Adviser Services provided that the requirements under paragraph (c)(7)(i)(C) of Rule 2-01 of Regulation S-X are met.

(e)(2) The percentage of services described in paragraphs (b) through (d) of this Item approved pursuant to the “de minimis” exception under paragraph (c)(7)(i)(C) of Rule 2-01 of Regulation S-X during both fiscal years ended December 31, 2009 and December 31, 2008 was zero.

(f) Not applicable.

(g) The aggregate non-audit fees billed by the registrant’s accountant for services rendered to the registrant, and rendered to the registrant’s investment adviser (not including any sub-adviser whose role is primarily portfolio management and is subcontracted with or overseen by another investment adviser), and any entity controlling, controlled by, or under common control with the adviser that provides ongoing services to the registrant for the fiscal years ended December 31, 2009 and December 31, 2008 are approximately as follows:

2009		2008
$	119,500	$	218,500

(h) The registrant’s Audit Committee of the Board of Directors has considered whether the provision of non-audit services that were rendered to the registrant’s adviser (not including any sub-adviser whose role is primarily portfolio management and is subcontracted with or overseen by another investment adviser), and any entity controlling, controlled by, or under common control with the investment adviser that provides ongoing services to the registrant that were not pre-approved pursuant to paragraph (c)(7)(ii) of Rule 2-01 of Regulation S-X, is compatible with maintaining the principal accountant’s independence.

Item 5. Audit Committee of Listed Registrants.

Not applicable.

Item 6. Investments

(a)The registrant’s “Schedule I — Investments in securities of unaffiliated issuers” (as set forth in 17 CFR 210.12-12) is included in Item 1 of this Form N-CSR.

(b)Not applicable

Item 7. Disclosure of Proxy Voting Policies and Procedures for Closed-End Management Investment Companies.

Not applicable.

Item 8. Portfolio Managers of Closed-End Management Investment Companies.

Not applicable.

Item 9. Purchases of Equity Securities by Closed-End Management Investment Company and Affiliated Purchasers.

Not applicable.

Item 10. Submission of Matters to a Vote of Security Holders.

There have not been any material changes to the procedures by which shareholders may recommend nominees to the registrant’s board of directors, since those procedures were last disclosed in response to requirements of Item 407(c)(2)(iv) of Regulation S-K (as required by Item 22(b)(15) of Schedule 14A) or this Item.

Item 11. Controls and Procedures.

(a)The registrant’s principal executive officer and principal financial officers, based on their evaluation of the registrant’s disclosure controls and procedures as of a date within 90 days of the filing of this report, have concluded that such controls and procedures are adequately designed to ensure that information required to be disclosed by the registrant in Form N-CSR is accumulated and communicated to the registrant’s management, including the principal executive officer and principal financial officer, or persons performing similar functions, as appropriate to allow timely decisions regarding required disclosure.

(b)There was no change in the registrant’s internal control over financial reporting that occurred during the registrant’s second fiscal quarter of the period covered by this report that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting.

Item 12. Exhibits.

(a)(1) Code of ethics required to be disclosed under Item 2 of Form N-CSR attached hereto as Exhibit 99.CODE ETH.

(a)(2) Certifications pursuant to Rule 30a-2(a) under the Investment Company Act of 1940 (17 CFR 270.30a-2(a)) attached hereto as Exhibit 99.CERT.

(a)(3) Not applicable.

(b) Certification pursuant to Rule 30a-2(b) under the Investment Company Act of 1940 (17 CFR 270.30a-2(b)) attached hereto as Exhibit 99.906CERT.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

(registrant) Columbia Acorn Trust

By (Signature and Title)	/s/ Charles P. McQuaid
	Charles P. McQuaid, President

Date February 19, 2010

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, this report has been signed below by the following persons on behalf of the registrant and in the capacities and on the dates indicated.

By (Signature and Title)	/s/ Charles P. McQuaid
	Charles P. McQuaid, President

Date February 19, 2010

By (Signature and Title)	/s/ Bruce H. Lauer
	Bruce H. Lauer, Treasurer

Date February 19, 2010

EX-99.CODEETH

Exhibit 99.CODEETH

COLUMBIA WANGER ASSET MANAGEMENT ADVISED FUNDS

CODE OF ETHICS FOR PRINCIPAL EXECUTIVE

AND SENIOR FINANCIAL OFFICERS

I.Covered Officers/Purpose of the Code

This Code of Ethics (the “Code”) for the investment companies within the Columbia Wanger Asset Management fund complex (collectively the “Funds” and each, a “Fund”) applies the Funds’ Principal Executive Officer, Principal Financial Officer, and Principal Accounting Officer (the “Covered Officers”) for the purpose of promoting:

·honest and ethical conduct, including the ethical handling of actual or apparent conflicts of interest between personal and professional relationships;

·full, fair, accurate, timely and understandable disclosure in reports and documents that a Fund files with, or submits to, the Securities and Exchange Commission (“SEC”), and in other public communications made by a Fund;

·compliance with applicable laws and governmental rules and regulations;

·the prompt internal reporting of violations of the Code to an appropriate person or persons identified in the Code; and

·accountability for adherence to the Code.

Each Covered Officer shall adhere to a high standard of business ethics and shall be sensitive to situations that may give rise to actual or apparent conflicts of interest.

II.Administration of the Code

The Code shall be administered by the Columbia Wanger Asset Management Compliance Department.  The Boards of Trustees of the Funds (collectively, the “Board”) shall designate an individual to be primarily responsible for the administration of the Code (the “Code Officer”).  In the absence of the Code Officer, his or her designee shall serve as the Code Officer, but only on a temporary basis.

Each Fund has designated a chief legal officer (the “Chief Legal Officer”) for purposes of the Sarbanes-Oxley Act of 2002 and the rules promulgated thereunder.  The Chief Legal Officer shall assist the Code Officer in administration of this Code.  The Chief Legal Officer is responsible for applying this Code to specific situations in which questions are presented under it (in consultation with Fund counsel, where appropriate) and has the authority to interpret this Code in any particular situation.  However, any waivers sought by

a Covered Officer must be approved by each Audit Committee of the Funds (collectively, the “Audit Committee”).

III.Managing Conflicts of Interest

Overview.  A “conflict of interest” occurs when a Covered Officer’s private interest interferes with the interests of, or his/her service to, a Fund. For example, a conflict of interest would arise if a Covered Officer, or a family member, receives improper personal benefits as a result of the Covered Officer’s position with a Fund.

Certain conflicts of interest arise out of the relationships between Covered Officers and a Fund and already are subject to conflict of interest provisions in the Investment Company Act of 1940 (the “Company Act”) and the Investment Advisers Act of 1940 (the “Advisers Act”).  For example, Covered Officers may not individually engage in certain transactions (such as the purchase or sale of securities or other property) with a Fund because of their status as “affiliated persons” of the Fund.  A Fund’s and its investment adviser’s compliance programs and procedures are designed to prevent, or identify and correct, violations of those provisions.  This Code does not, and is not intended to, repeat or replace those programs and procedures, and such conflicts fall outside of the parameters of this Code.

Although typically not presenting an opportunity for improper personal benefit, conflicts may arise from, or as a result of, the contractual relationship between a Fund and its investment adviser, administrator, pricing and bookkeeping agent and/or transfer agent (each, a “Service Provider”) of which the Covered Officers are also officers or employees.  As a result, this Code recognizes that the Covered Officers will, in the normal course of their duties (whether formally for a Fund or for a Service Provider, or for both), be involved in establishing policies and implementing decisions that will have different effects on the Service Provider and a Fund.  The participation of the Covered Officers in such activities is inherent in the contractual relationship between the Fund and the Service Provider and is consistent with the performance by the Covered Officers of their duties as officers of a Fund.  In addition, it is recognized by the Board that the Covered Officers may also be officers or employees of one or more other investment companies covered by this or other codes.

Other conflicts of interest are covered by the Code, even if such conflicts of interest are not subject to provisions of the Company Act and the Advisers Act.  The following list provides examples of conflicts of interest under the Code, but Covered Officers should keep in mind that these examples are not exhaustive.  The overarching principle is that the personal interest of a Covered Officer should not be placed improperly before the interest of a Fund.

Each Covered Officer must:

·not use personal influence or personal relationships to influence investment decisions or financial reporting by a Fund whereby the Covered Officer or a family member would benefit personally to the detriment of a Fund;

·not cause a Fund to take action, or fail to take action, for the individual personal benefit of the Covered Officer or a family member rather than the benefit of the Fund.

There are some conflict of interest situations that must be approved by the Code Officer, after consultation with the Chief Legal Officer.  Those situations include, but are not limited to,:

·service as director on the board of any public or private company;

·the receipt of any gifts in excess of $100 in the aggregate from a third party that does or seeks to do business with the Funds during any 12-month period;

·the receipt of any entertainment from any company with which a Fund has current or prospective business dealings, unless such entertainment is business-related, reasonable in cost, appropriate as to time and place, and not so frequent as to raise any question of impropriety;

·any material ownership interest in, or any consulting or employment relationship with, any Fund service providers, other than its investment adviser, principal underwriter, administrator or any affiliated person thereof;

·a direct or indirect material financial interest in commissions, transaction charges or spreads paid by a Fund for effecting portfolio transactions or for selling or redeeming shares other than an interest arising from the Covered Officer’s employment, such as compensation or equity ownership.

IV.Disclosure and Compliance

Each Covered Officer shall:

·be familiar with the disclosure requirements generally applicable to the Funds;

·not knowingly misrepresent, or cause others to misrepresent, facts about any Fund to others, whether within or outside the Fund, including to the Fund’s trustees and auditors, and to governmental regulators and self-regulatory organizations;

·to the extent appropriate within his/her area of responsibility, consult with other officers and employees of the Funds and the adviser with the goal of promoting full, fair, accurate, timely and understandable

disclosure in the reports and documents the Funds file with, or submit to, the SEC and in other public communications made by the Funds; and

·promote compliance with the standards and restrictions imposed by applicable laws, rules and regulations.

V.Reporting and Accountability

Each Covered Officer must:

·upon adoption of the Code (or after becoming a Covered Officer), affirm in writing to the Board that he/she has received, read and understands the Code;

·annually affirm to the Board compliance with the requirements of the Code;

·not retaliate against any other Covered Officer or any employee of the Funds or their affiliated persons for reports of potential violations that are made in good faith;

·notify the Chief Legal Officer and the Code Officer promptly if he/she knows of any violation of this Code; and

·respond to the trustee and officer questionnaires circulated periodically in connection with the preparation of disclosure documents for the Funds.

The Code Officer shall maintain records of all activities related to this Code.

The Funds will follow the procedures set forth below in investigating and enforcing this Code:

·The Chief Legal Officer and/or the Code Officer will take all appropriate action to investigate any potential violation reported to him/her;

·If, after such investigation, the Chief Legal Officer and the Code Officer believes that no violation has occurred, the Code Officer will notify the person(s) reporting the potential violation, and no further action is required;

·Any matter that the Chief Legal Officer and/or the Code Officer believes is a violation will be reported to the Audit Committee;

·If the Audit Committee concurs that a violation has occurred, it will inform and make a recommendation to the Board, which will consider appropriate action, which may include review of, and appropriate modifications to, applicable policies and procedures; notification to the Chief Executive Officer of Columbia Management Group; or a recommendation to sanction or dismiss the Covered Officer;

·The Audit Committee will be responsible for granting waivers in its sole discretion;

·Any changes to or waivers of this Code will, to the extent required, be disclosed as provided by SEC rules.

The Chief Legal Officer shall:

·report to the Audit Committee quarterly any approvals provided in accordance with Section II of this Code; and

·report to the Audit Committee quarterly any violations of, or material issues arising under, this Code.

VI.Other Policies and Procedures

This Code shall be the sole code of ethics adopted by the Funds for the purposes of Section 406 of the Sarbanes-Oxley Act and the rules and forms applicable to registered investment companies thereunder.  Insofar as other polices or procedures of the Funds or the Funds’ Service Providers govern or purport to govern the behavior or activities (including, but not limited to, personal trading activities) of the Covered Officers who are subject to this Code, they are superseded by this Code to the extent that they overlap or conflict with the provisions of this Code.  The Funds’ and their investment advisers’ and principal underwriter’s codes of ethics under Rule 17j-1 under the Company Act and any policies and procedures of the Service Providers are separate requirements applicable to the Covered Officers and are not part of this Code.

VII.    Amendments

All material amendments to this Code must be approved or ratified by the Board, including a majority of independent directors.

VIII.   Confidentiality

All reports and records prepared or maintained pursuant to this Code will be considered confidential and shall be maintained and protected accordingly.  Except as otherwise required by law or this Code, such matters shall not be disclosed to anyone other than the Board, the Covered Officers, the Chief Legal Officer, outside audit firms and legal counsel to the Funds, and senior management of Columbia Management Group.

IX.Internal Use

The Code is intended solely for the internal use by the Funds and does not constitute an admission, by or on behalf of any Fund, as to any fact, circumstance, or legal conclusion.

COLUMBIA WANGER ASSET MANAGEMENT ADVISED FUNDS

CODE OF ETHICS FOR PRINCIPAL EXECUTIVE

AND SENIOR FINANCIAL OFFICERS (“CODE”) — AFFIRMATION

I affirm that:

1.Upon the adoption of the Code, I have received, read and understand the Code and have complied with the Code since its adoption on September 23, 2003.

Signature Date

EX-99.CERT

Exhibit 99.CERT

I, Charles P. McQuaid, certify that:

1.I have reviewed this report on Form N-CSR of Columbia Acorn Trust;

2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3.Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations, changes in net assets, and cash flows (if the financial statements are required to include a statement of cash flows) of the registrant as of, and for, the periods presented in this report;

4.The registrant’s other certifying officers and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Rule 30a-3(c) under the Investment Company Act of 1940) and internal control over financial reporting (as defined in Rule 30a-3(d) under the Investment Company Act of 1940) for the registrant and have:

(a)designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

(b)designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

(c)evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of a date within 90 days prior to the filing date of this report based on such evaluation; and

(d)disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s second fiscal quarter of the period covered by this report that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

5.The registrant’s other certifying officers and I have disclosed to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):

(a)all significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize, and report financial information; and

(b)any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

Date:	February 19, 2010	/s/ Charles P. McQuaid
		Charles P. McQuaid, President

I, Bruce H. Lauer, certify that:

1.I have reviewed this report on Form N-CSR of Columbia Acorn Trust;

2.Based on my knowledge, this report does not contain any untrue statement of a material fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this report;

3.Based on my knowledge, the financial statements, and other financial information included in this report, fairly present in all material respects the financial condition, results of operations, changes in net assets, and cash flows (if the financial statements are required to include a statement of cash flows) of the registrant as of, and for, the periods presented in this report;

4.The registrant’s other certifying officers and I are responsible for establishing and maintaining disclosure controls and procedures (as defined in Rule 30a-3(c) under the Investment Company Act of 1940) and internal control over financial reporting (as defined in Rule 30a-3(d) under the Investment Company Act of 1940) for the registrant and have:

(a)designed such disclosure controls and procedures, or caused such disclosure controls and procedures to be designed under our supervision, to ensure that material information relating to the registrant, including its consolidated subsidiaries, is made known to us by others within those entities, particularly during the period in which this report is being prepared;

(b)designed such internal control over financial reporting, or caused such internal control over financial reporting to be designed under our supervision, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles;

(c)evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented in this report our conclusions about the effectiveness of the disclosure controls and procedures, as of a date within 90 days prior to the filing date of this report based on such evaluation; and

(d)disclosed in this report any change in the registrant’s internal control over financial reporting that occurred during the registrant’s second fiscal quarter of the period covered by this report that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting; and

5.The registrant’s other certifying officers and I have disclosed to the registrant’s auditors and the audit committee of the registrant’s board of directors (or persons performing the equivalent functions):

(a)all significant deficiencies and material weaknesses in the design or operation of internal control over financial reporting which are reasonably likely to adversely affect the registrant’s ability to record, process, summarize, and report financial information; and

(b)any fraud, whether or not material, that involves management or other employees who have a significant role in the registrant’s internal control over financial reporting.

Date:	February 19, 2010	/s/ Bruce H. Lauer
		Bruce H. Lauer, Treasurer

EX-99.906CERT

Exhibit 99.906CERT

CERTIFICATION PURSUANT TO SECTION 906 OF

THE SARBANES-OXLEY ACT OF 2002

In connection with the Certified Shareholder Report of Columbia Acorn Trust (the “Trust”) on Form N-CSR for the period ending December 31, 2009, as filed with the Securities and Exchange Commission on the date hereof (“the Report”), the undersigned hereby certifies that, to his knowledge:

1.The Report fully complies with the requirements of Section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

2.The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Trust.

Date:  February 19, 2010	/s/ Charles P. McQuaid
	Charles P. McQuaid, President

Date:  February 19, 2010	/s/ Bruce H. Lauer
	Bruce H. Lauer, Treasurer

A signed original of this written statement required by Section 906 of the Sarbanes-Oxley Act of 2002 has been provided to the Registrant and will be retained by the Registrant and furnished to the Securities and Exchange Commission (the “Commission”) or its staff upon request.

This certification is being furnished to the Commission solely pursuant to 18 U.S.C. §1350 and is not being filed as part of the Form N-CSR with the Commission.