N-CSRS

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)
225 Franklin Street, Boston, Massachusetts					02110
(Address of principal executive offices)					(Zip code)
Scott R. Plummer 5228 Ameriprise Financial Center Minneapolis, MN 55474
(Name and address of agent for service)
Registrant’s telephone number, including area code:				1-612-671-1947
Date of fiscal year end:	December 31
Date of reporting period:		June 30, 2011

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.

Q2 2011

Columbia Acorn Family of Funds

Class Z Shares

Managed by Columbia Wanger Asset Management, LLC

Semiannual Report

June 30, 2011

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 • No bank guarantee • May lose value

Columbia Acorn Family of Funds

Descriptions of Indexes Included in this Report

•50/50 Blended Benchmark, established by the Fund's adviser, 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, including Columbia Acorn Fund and Columbia Acorn Select; Lipper International Small/Mid Growth Funds Index, 10 largest non-U.S. small/mid growth funds, including Columbia Acorn International; Lipper Small-Cap Growth Funds Index, 30 largest small-cap growth funds, including Columbia Acorn USA; 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 (Net) is a capitalization-weighted index that tracks the total return of common stocks in 22 developed-market countries within Europe, Australasia and the Far East. The returns of the MSCI EAFE Index (Net) are presented net of the withholding tax rate applicable to foreign non-resident institutional investors in the foreign companies included in the index who do not benefit from double taxation treaties.

•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 $2B and $10B 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 consists of the bottom 20% of institutionally investable capital of developed and emerging countries, outside the United States.

•S&P Global Ex-U.S. Between $500M and $5B 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's 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.

Columbia Acorn Funds News

Introducing Columbia^SM Acorn® Emerging Markets Fund and Columbia^SM Acorn® European Fund

On August 22, 2011, we launched two new Columbia Acorn Funds: Columbia Acorn Emerging Markets Fund and Columbia Acorn European Fund. These Funds utilize Columbia Wanger Asset Management's time-tested approach to investing, which centers on finding small- to mid-cap stocks in growing businesses with solid long-term prospects. In recent years, our nine international and global analysts have visited over 50 countries in search of investment ideas. These analysts include the portfolio managers running our new Funds, each of whom has exhibited excellent stock-picking skills.

Within the emerging markets, we've noted that most funds invest in large-cap stocks. Their focus is often commodity producers, whose businesses are tied to world macroeconomics, or financial companies, some of which may be quite risky. By focusing on smaller stocks, Columbia Acorn Emerging Markets Fund invests in what we believe to be more innovative, well-run niche businesses, priced at reasonable valuations. We believe that these types of companies should benefit from providing sought-after products and services to growing numbers of local, middle-class consumers, who have increasing spending power. We also believe that many of these companies experience lower levels of competition and better opportunities to internally reinvest profits than larger cap or developed market companies.

Likewise, Columbia Acorn European Fund has a small- to mid-cap stock focus. Because European companies operate in fairly small domestic markets, many are adept at creating niche products that have international appeal. European companies lead the world in machine tool manufacturing, products used to promote energy efficiency, luxury goods items, rail technology and some areas of medical technology. These products are needed, or wanted, in both developed and developing world markets. The integration of the European Union into a single trade zone with a common currency has created greater efficiency and productivity within the region, and opportunities to improve the infrastructure in Central and Eastern Europe are plentiful. Columbia Acorn European Fund's managers have extensive experience investing within the European markets and manage a similar offshore fund, Wanger European Smaller Companies Fund, which is not available to U.S.-domiciled investors.

I am personally investing in both Funds, as are the new Funds' portfolio managers. The Funds entail specific risks that are outlined in their prospectuses, and they may not be suitable for all investors. If interested, please call 1-800-922-6769 or your broker for a prospectus.

New Co-manager Named to Columbia Acorn Select Investment Team

I am pleased to announce that Robert Chalupnik has been named co-manager of Columbia Acorn Select, effective May 1, 2011. Since 2000, Rob has followed industrial stocks as a Columbia Wanger Asset Management analyst. Rob has excelled in finding growing niche businesses selling at reasonable prices. Over his 10 years as an analyst, he has distinguished himself by substantially beating his custom benchmark, which is comprised of most of the industrial stocks included in the Russell 2500 Index. Three of Rob's finds were among the top-10 positions in Columbia Acorn Fund at the end of period. Rob has worked with Columbia Acorn Select lead portfolio manager Ben Andrews since January of this year and together they have added what we believe to be some of Columbia Wanger Asset Management's best ideas into Columbia Acorn Select. Ben remains lead manager of the Fund and welcomes Rob in his new role.

Charles P. McQuaid

President and Chief Investment Officer
Columbia Wanger Asset Management, LLC

Investors should consider the investment objectives, risks, charges and expenses of a mutual fund carefully before investing. For a free prospectus, which contains this and other important information about the fund, visit columbiamanagement.com. The prospectus should be read carefully before investing.

The 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.

There is no guarantee that any investment strategy will deliver favorable results. The market value of securities and currencies may fall or fail to rise. Market risk may affect a single issuer, sector of the economy, industry or the market as a whole. Investments in foreign securities involve certain risks not associated with investments in U.S. companies, due to political, regulatory, economic, social and other conditions or events occurring in the country, as well as fluctuations in currency and the risks associated with less developed custody and settlement practices. Risks are particularly significant in emerging markets. Investments in small-capitalization companies involve greater risks and volatility than investments in larger, more established companies. See the prospectus for more information on these and other risks associated with the Fund.

Columbia Acorn Family of Funds

Table of Contents

Performance At A Glance	1
Squirrel Chatter II: Shale Gas Returns, Transforming the Energy Outlook	2
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	36
Statement of Investments	38
Portfolio Diversification	47
Columbia Acorn USA
In a Nutshell	12
At a Glance	13
Major Portfolio Changes	48
Statement of Investments	49
Columbia Acorn International Select
In a Nutshell	14
At a Glance	15
Major Portfolio Changes	56
Statement of Investments	57
Portfolio Diversification	61

Columbia Acorn Select
In a Nutshell	16
At a Glance	17
Major Portfolio Changes	62
Statement of Investments	63
Columbia Thermostat Fund
In a Nutshell	18
At a Glance	19
Statement of Investments	68
Columbia Acorn Family of Funds
Statements of Assets and Liabilities	70
Statements of Operations	71
Statements of Changes in Net Assets	72
Financial Highlights	76
Notes to Financial Statements	79
Management Fee Evaluation of the Senior Officer	87
Board Approval of the Advisory Agreement	93
Columbia Acorn Family of Funds Information	96

2011 Mid-Year Distributions

The following table lists the mid-year distributions for Columbia Acorn Fund, Columbia Acorn International, Columbia Acorn International Select, Columbia Acorn Select and Columbia Thermostat Fund. Columbia Acorn USA did not have mid-year distributions. The record date was June 7, 2011, and the ex-dividend date and the payable date was June 8, 2011.

	Short-term Capital Gains		Long-term Capital Gains		Ordinary Income		Reinvestment Price
Columbia Acorn Fund		None	$	0.3037	$	0.0830	$	30.40
Columbia Acorn International		None		None	$	1.0248	$	41.10
Columbia Acorn International Select		None		None	$	0.4137	$	29.19
Columbia Acorn Select		None		None	$	0.4600	$	26.76
Columbia Thermostat Fund		None		None	$	0.1564	$	12.64

Columbia Acorn Family of Funds

Performance At A Glance Class Z Average Annual Total Returns through 6/30/11

	NAV on 6/30/11		2nd quarter*			Year to date*			1 year			3 years			5 years			10 years			Life of Fund
Columbia Acorn Fund (ACRNX) (6/10/70)	$	31.95		1.43	%		7.18	%		39.46	%		8.42	%		6.19	%		9.21	%		15.01	%
Russell 2500 Index				-0.59	%		8.06	%		39.28	%		8.17	%		5.20	%		7.40	%		NA
S&P 500 Index**				0.10	%		6.02	%		30.69	%		3.34	%		2.94	%		2.72	%		10.67	%
Lipper Small-Cap Core Funds Index				-1.36	%		6.18	%		36.32	%		7.54	%		4.74	%		6.91	%		NA
Lipper Mid-Cap Growth Funds Index				-0.04	%		7.57	%		39.76	%		5.63	%		6.86	%		4.73	%		NA
Columbia Acorn International (ACINX) (9/23/92)	$	41.13		1.70	%		3.02	%		32.28	%		4.24	%		7.35	%		11.31	%		12.00	%
S&P Global Ex-U.S. Between $500M and $5B Index				0.72	%		2.63	%		34.29	%		5.43	%		7.09	%		12.71	%		9.34	%
S&P Global Ex-U.S. SmallCap Index				0.59	%		3.62	%		35.68	%		4.10	%		5.91	%		11.92	%		8.61	%
MSCI EAFE Index (Net)				1.56	%		4.98	%		30.36	%		-1.77	%		1.48	%		5.66	%		6.35	%
Lipper International Small/ Mid Growth Funds Index				1.69	%		2.88	%		36.54	%		2.35	%		4.85	%		9.71	%		NA
Columbia Acorn USA (AUSAX) (9/4/96)	$	31.17		1.50	%		9.14	%		43.38	%		8.09	%		4.85	%		7.19	%		10.86	%
Russell 2000 Index				-1.61	%		6.21	%		37.41	%		7.77	%		4.08	%		6.27	%		7.73	%
Russell 2500 Index				-0.59	%		8.06	%		39.28	%		8.17	%		5.20	%		7.40	%		9.40	%
S&P 500 Index**				0.10	%		6.02	%		30.69	%		3.34	%		2.94	%		2.72	%		6.72	%
Lipper Small-Cap Growth Funds Index				0.23	%		9.07	%		41.91	%		7.60	%		4.77	%		4.04	%		6.26	%
Columbia Acorn Int'l Select (ACFFX) (11/23/98)	$	28.98		1.10	%		3.74	%		31.33	%		-0.26	%		7.22	%		9.50	%		10.23	%
S&P Developed Ex-U.S. Between $2B and $10B Index				0.90	%		4.04	%		33.74	%		1.73	%		3.73	%		9.60	%		8.36	%
MSCI EAFE Index (Net)				1.56	%		4.98	%		30.36	%		-1.77	%		1.48	%		5.66	%		4.20	%
Lipper International Small/ Mid Growth Funds Index				1.69	%		2.88	%		36.54	%		2.35	%		4.85	%		9.71	%		11.13	%
Columbia Acorn Select (ACTWX) (11/23/98)	$	28.25		-0.95	%		0.02	%		29.03	%		3.29	%		5.17	%		8.41	%		10.68	%
S&P MidCap 400 Index				-0.73	%		8.56	%		39.38	%		7.82	%		6.60	%		7.94	%		9.79	%
S&P 500 Index**				0.10	%		6.02	%		30.69	%		3.34	%		2.94	%		2.72	%		2.82	%
Lipper Mid-Cap Growth Funds Index				-0.04	%		7.57	%		39.76	%		5.63	%		6.86	%		4.73	%		6.86	%
Columbia Thermostat Fund (COTZX) (9/25/02)†	$	12.86		1.47	%		4.66	%		25.39	%		5.82	%		5.81	%		—			7.94	%
S&P 500 Index				0.10	%		6.02	%		30.69	%		3.34	%		2.94	%		—			7.72	%
Barclays Capital U.S. Aggregate Bond Index				2.29	%		2.72	%		3.90	%		6.46	%		6.52	%		—			5.06	%
Lipper Flexible Portfolio Funds Index				0.46	%		5.11	%		23.38	%		4.00	%		5.16	%		—			8.28	%
50/50 Blended Benchmark††				1.21	%		4.40	%		16.88	%		5.45	%		5.14	%		—			6.71	%

*Not annualized.

**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.

Performance data shown represents past performance and is not a guarantee of future results. The investment return and principal value of an investment will fluctuate so that shares, when redeemed, may be worth more or less than their original cost. Current performance may be lower or higher than the performance data shown. Please visit columbiamanagement.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 distribution and service (Rule 12b-1) fees. 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 adviser 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 stated as of 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: 0.98%. Columbia Acorn USA Class Z: 1.01%. Columbia Acorn International Select Class Z: 1.16%. Columbia Acorn Select Class Z: 0.97%. Columbia Thermostat Fund has a contractual expense waiver or reimbursement that expires April 30, 2012. 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 1.16% and 1.04%, respectively.

†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 adviser.

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.

1

Squirrel Chatter II: Shale Gas Returns, Transforming the Energy Outlook

Just five to seven years ago, it was widely believed that North American natural gas resources were being rapidly depleted. Today, the outlook appears to be very much improved thanks to the ingenuity of a few individuals and a process that should provide natural gas for decades to come.

In 1825, some 34 years before Colonel Edwin Drake¹ drilled the first oil well in Titusville, Pennsylvania, William Aaron Hart drilled the first natural gas well, in shale located in Fredonia, New York. By August of that year, five structures in the village were illuminated by natural gas and by November there were 36 gas lights in the village. In 1857, Preston Barmore, the superintendent of the Fredonia Natural Gas Co., was not satisfied with the production from a 122 foot well so he exploded crevices of rock in the well, increasing the supply of gas. Within a few years, the village had 150 gas lights.²

Plenty of natural gas was subsequently found in sandstone formations under impermeable rock, in similar formations as oil, or accompanied by oil. Extracting this natural gas was less costly than drilling for gas in shale, so shale exploration all but ended. Over 300,000 miles of gas pipelines were built, and demand for natural gas grew.³ U.S.-marketed production rose to 1 trillion cubic feet (TCF) of natural gas by 1923, and has ranged from 16.9 to 22.6 TCF since 1973.⁴ Natural gas is used for heating and manufacturing, and is a feedstock for fertilizers, plastics and chemicals.

Recent Natural Gas Shortages

In 2004, Julian Darley wrote High Noon for Natural Gas, The New Energy Crisis. He reviewed Hubbert's Peak, a theory named after the geologist who researched oil finding and production curves and then correctly predicted that U.S. oil production would peak around 1970. Darley applied Hubbert's Peak to natural gas data and concluded that North American gas production had also peaked and was likely to plunge.

Darley wrote, "The United States and Canada are entering a natural gas crisis ...North American supply is simply no longer able to meet desired consumption."⁵ He added, "...the worst immediate problem confronting the United States (and Canada) is not oil, but natural gas. It is a natural gas shortage that could seriously interrupt the U.S. economy..."⁶ Darley noted that the U.S. Energy Information Administration (EIA) made enormous upward revisions for production of natural gas from shale, tight sands and coal beds, but he believed such gains would fail to occur. Instead, importing of liquefied natural gas (LNG) would have to be an interim solution. But LNG, Darley stated, had safety and security risks. Geopolitically, relying on imported LNG would also be problematic, as Russia and Iran had the largest reserves of natural gas.

Darley believed that the 300-plus new natural gas-fired electric generating stations, built between 1980 and 2003 at a cost of $100 billion, were huge mistakes. The power companies had apparently reviewed a 1999 National Petroleum Council report that stated North American natural gas supplies would grow. Darley labeled that report as an "example of the kind of cornucopian delusion that characterizes many in government and most in industry, who believe in nothing but economics and the miracle of capitalism with its unlimited ability to find substitutes for everything."⁷

Darley thought that with worldwide Peak Oil imminent and North American natural gas production plunging, energy was to become scarce, and the industrial revolution would unwind. He advocated that people should be able to obtain their daily needs within walking distance from where they lived. His long-term solution was to depopulate the earth, such that mankind no longer mined the planet and consumed only the energy that the sun regularly provides. At one child per woman, the population of the earth would be back to one billion in about one hundred years.

Domestic natural gas production fell between 2001 and 2005 and prices increased between 2002 and 2008.⁸ Most major oil companies and analysts agreed that natural gas production in North America was peaking, and that the U.S. would need substantial imports of LNG. I remember going to an energy conference in early 2006 where this

2

view was widespread. Darley's nightmare scenario seemed to be coming true.

Back in the Gas Fields

George Mitchell has been called the Father of the Barnett Natural Gas Field, located in and around Fort Worth, Texas. Over an 18-year period beginning in 1981, his company, Mitchell Energy and Development, experimented with fracturing gas-bearing shale that is located between 6,000 and 14,000 feet below the surface. Geologists knew that shale had lots of pores and the ability to store natural gas, but since pores in shale are rarely interconnected, gas flows poorly through shale. Initial attempts to extract this gas were costly, and production was not economical. Eventually, the company developed a "light sand frac" method that was effective and used less fluid. The combination of reduced costs and rising natural gas prices made such drilling profitable. Mitchell drilled many wells at the Barnett field, producing far more natural gas than most people expected.⁹

Mitchell needed more funding and sold his company to Devon Energy, a larger, independent producer. Devon had expertise in an additional technology, horizontal drilling, which tilted drill holes at angles or sideways once they hit pay dirt. More gas-bearing shale was consequently exposed to the well. With this added technology, the company drilled 55 wells in the Barnett field in 2003 and the shale gas boom began.¹⁰ Some 13,500 gas wells have been drilled in the Barnett field since 1997¹¹ and the Barnett field accounted for 6% of total natural gas production in the United States in 2010.¹²

Drilling at other shale gas formations has also jumped. U.S. shale gas production increased 12-fold in the last decade and currently accounts for about 25% of U.S. natural gas production.¹³ With greater production, natural gas wellhead prices halved from 2008 to 2010. In its yearly forecast in 2010, the EIA doubled its estimate of U.S. shale gas production for 2035 and predicts shale gas production will hit 46% of U.S. consumption that year.¹⁴ Imports will drop from 11% of natural gas consumption in 2009 to 1%.¹⁵ With "economics and the miracle of capitalism,"¹⁶ we won't need to revert to Darley's dark ages any time soon. The EIA also believes shale gas totaling at least six-times U.S. reserves is recoverable in at least 32 other countries.¹⁷

Energy Mix

In 2009, Robert Hefner published The Grand Energy Transition. The book provides perspectives on past and future sources and uses of energy. Hefner believes that energy usage naturally transitions from solids (wood and coal) to liquids (oil) and then to gasses (natural gas, wind and hopefully nuclear fusion). He sees newer fuels as superior to older ones, with each new fuel facilitating new technologies, improvements in the environment and higher living standards.

The transition to coal from wood powered the industrial revolution and allowed millions of acres of forests to regrow. Coal then fell from 80% of the world energy market in 1900 to about 28% currently. Oil ascended to 48% of the world's energy by 1973, displacing much dirty coal and revolutionizing transportation via the introduction of automobiles and airplanes. Oil subsequently dropped to about 36% of world energy consumption. Natural gas has risen from 10% of the world's energy in 1950 to 24% currently.¹⁸

Believing in global warming, Hefner notes that the transition from wood to coal to oil to natural gas slashed carbon content and increased hydrogen content of fuels with each transition. Since burning carbon creates carbon dioxide (CO₂), the primary greenhouse gas, and burning hydrogen creates water, the natural transitions from solids to liquids to gasses slow global warming. Burning natural gas creates 44% less CO₂ than burning coal and 29% less than burning oil. Burning natural gas also emits about 80% less nitrogen oxides, over 90% lower particulates and over 99% less sulfur dioxide than coal or oil.¹⁹

Under an earlier belief that the United States was running out of natural gas, the Natural Gas Policy Act (NGPA) and the Fuel Use Act were passed in 1978. The NGPA immediately deregulated prices for gas produced from deep wells and phased out other price controls.²⁰ The Fuel Use Act mandated the phase out of natural gas for electric generation and restricted its industrial uses. Prices for deep gas jumped, but so did drilling. Production grew, and with demand depressed by the Fuel Use Act, prices then collapsed. There was an excess supply of natural gas, known as the "gas bubble," until the year 2000.

Hefner believes that prior price controls and the Fuel Use Act slowed the natural transition from coal and oil to

3

natural gas. As a result of the Fuel Use Act, some 100,000 megawatts of coal-fired electric generating capacity was built in the United States through 1989 that has emitted 15 billion metric tons of CO₂ into the atmosphere.²¹ Hefner believes that the construction of the coal burning plants, not the natural gas burning plants, was the big mistake.

Hefner subscribes to Peak Oil occurring soon, but sees many decades of abundant and relatively cheap natural gas. Hence, he predicts the grand energy transition to natural gas will continue, and he believes natural gas will be a bridge fuel to renewable energy and possibly nuclear fusion. Natural gas complements wind energy quite well, as gas-burning electric plants can quickly power up when the wind slows.

Some 12 million vehicles worldwide are powered by natural gas. Of that number, there are estimated to be 110,000 natural gas-powered vehicles in the United States,²² including thousands of trucks serving the ports of Long Beach and Los Angeles,²³ more than 11,000 buses²⁴ and approximately 12,000 Honda Civic GX cars.²⁵ These vehicles burn natural gas currently priced at one-third of the energy equivalent price of oil. Hefner believes that half the autos in the United States should be powered by natural gas, and the dirtiest, coal-burning electric plants should be replaced by natural gas plants. Yearly gas consumption would rise by 13 TCF, but could be met by increased shale gas production.²⁶

Investment Implications

We believe that innovations in producing gas from shale have indeed transformed the U.S. energy outlook. We profitably invested in some of the pioneers of shale gas though, with the current glut of natural gas, the stocks now look less attractive. Supplies of gas may remain high in the short term as some unprofitable drilling persists in order to keep lease rights. Over time, the low prices will likely result in reduced drilling and more constrained supplies. When this happens, natural gas prices should rise to a level where drilling and production are moderately profitable. We continue to look for suppliers and service companies participating in shale gas production. Some shale oil fields are now being developed, including the Bakken field in North Dakota and Canada and the Eagle Ford field in Texas. At this point, we don't think there will be enough shale oil production to revolutionize the oil market, but we do believe we have found some attractive stocks participating in those developments.

Charles P. McQuaid

President and Chief Investment Officer
Columbia Wanger Asset Management, LLC

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 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 behalf of any particular Columbia Acorn Fund.

¹  Colonel Edwin Drake was an American oil driller, credited with being the first to drill for oil in the United States.

²  Lash, Eileen and Gary, "The Early History of Natural Gas, Kicking Down the Well," The SUNY Fredonia Shale Research Institute, June 3, 2011, http://www.fredonia.edu/shaleinstitute/history.asp.

³  U.S. Energy Information Administration (EIA), http://www.eia.gov/pub/oil_gas/natural_gas/analysis_publications/ngpipeline/index.html.

⁴  EIA data, including imports primarily from Canada, states the U.S. has been using about 23 trillion cubic feet (TCF) of gas a year, including about 6.6 TCF for industrial purposes. www.eia.gov.

⁵  Darley, Julian, High Noon for Natural Gas, The New Energy Crisis, (White River Junction, Vermont, Chelsea Green Publishing Company 2004) p. 13.

⁶  Ibid., p. 2.

⁷  Ibid., p. 79-80.

⁸  According to EIA data, domestic natural gas production fell from 20.6 TCF in 2001 to 18.9 TCF in 2005. Average annual wellhead prices rose from $3 to $5 in 2002-2003 to $6 to $8 from 2006-2008. www.eia.gov.

⁹  Airhart, Marc, "The Father of the Barnett Natural Gas Field," http://geology.com/research/barnett-shale-father.html.

¹⁰  Yergin, Daniel, "Stepping on the Gas," Wall Street Journal, April 2, 2011.

¹¹  Presentation for the Organization of Economic Cooperation and Development (OECD), "Shale Gas and the Outlook for U.S. Natural Gas Markets and Global Gas Resources," June 21, 2011, http://www.eia.gov/pressroom/presentations/newell_06212011.pdf.

¹²  U.S. Department of Energy, Office of Fossil Energy and National Energy Technology Laboratory, "Modern Shale Gas, Development in the United States: A Primer," April 2009, p. ES-1, http://fossil.energy.gov/programs/oilgas/publications/
naturalgas_general/Shale_Gas_Primer_2009.pdf

¹³  Presentation for the Organization of Economic Cooperation and Development (OECD), "Shale Gas and the Outlook for U.S. Natural Gas Markets and Global Gas Resources," June 21, 2011, http://www.eia.gov/pressroom/presentations/newell_06212011.pdf.

4

¹⁴  Lomax, Simon, "Shale-Gas Output May Double by 2035, Reducing Energy Imports, U.S. Says," Bloomberg, December 16, 2010, http://www.bloomberg.com/news/2010-12-16/natural-gas-production-from-shale-may-double-by-35-u-s-agency-forecasts.html.

¹⁵  Presentation for the Organization of Economic Cooperation and Development (OECD), "Shale Gas and the Outlook for U.S. Natural Gas Markets and Global Gas Resources," June 21, 2011, http://www.eia.gov/pressroom/presentations/newell_06212011.pdf.

¹⁶  Darley, Julian, op. cit., p. 79-80.

¹⁷  Presentation for the Organization of Economic Cooperation and Development (OECD), "Shale Gas and the Outlook for U.S. Natural Gas Markets and Global Gas Resources," June 21, 2011, http://www.eia.gov/pressroom/presentations/newell_06212011.pdf.

¹⁸  Hefner III, Robert A., The Grand Energy Transition, (Hoboken, New Jersey, John Wiley & Sons, Inc. 2009) p. 27.

¹⁹  U.S. Department of Energy, Office of Fossil Energy and National Energy Technology Laboratory, "Modern Shale Gas, Development in the United States: A Primer," April 2009, p. 5, http://fossil.energy.gov/programs/oilgas/publications/naturalgas_general/Shale_
Gas_Primer_2009.pdf

²⁰  Hefner III, Robert A., op. cit., p. 120-121. Having been an independent explorer for natural gas, Hefner was well aware that gas existed in locations independently of oil. (He has been called the "Father of Deep Natural Gas" as his company drilled very deep wells finding only natural gas at very high pressure.) In the 1970s when geologists for major oil companies testified to Congress that the U.S. was running out of natural gas, Hefner dissented, believing that the shortage was caused by price controls in place since 1954. Price controls cause shortages of valuable commodities by boosting demand and restraining supplies.

²¹  Ibid., p. 122.

²²  Natural Gas Vehicles of America, http://www.ngvc.org/mktplace/index.html. Accessed July 20, 2011.

²³  Hefner III, Robert A., op. cit., p. 201.

²⁴  Natural Gas Vehicles of America, http://www.ngvc.org/mktplace/index.html. Accessed July 20, 2011.

²⁵  Oberman, Mira, "The Greenest Car You've (Likely) Never Heard Of," Agence France-Presse, April 11, 2011.

²⁶  Hefner III, Robert A., op. cit., p. 203.

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 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 information. 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 the "Compare With Other Funds" information for details on using the hypothetical data.

January 1, 2011 – June 30, 2011

	Account value at the beginning of the period ($)				Account value at the end of the period ($)				Expenses paid during 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		1,071.80		1,021.08		3.85		3.76		0.75
Columbia Acorn International		1,000.00		1,000.00		1,030.20		1,020.08		4.78		4.76		0.95
Columbia Acorn USA		1,000.00		1,000.00		1,091.40		1,019.89		5.13		4.96		0.99
Columbia Acorn International Select		1,000.00		1,000.00		1,037.40		1,019.09		5.81		5.76		1.15
Columbia Acorn Select		1,000.00		1,000.00		1,000.20		1,019.98		4.81		4.86		0.97
Columbia Thermostat Fund**		1,000.00		1,000.00		1,046.60		1,023.55		1.27		1.25		0.25

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, 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.

*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.

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

6

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 Investment Services, Corp., your account balance is available online at columbiamanagement.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 shown represents past performance and is not a 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. Current performance may be lower or higher than the performance data shown. Please visit columbiamanagement.com for daily and most recent month-end performance updates.

Fund Positions
in Mentioned Holdings

As a percentage of net assets, as of 6/30/11

lululemon athletica	2.3	%
Informatica	1.4	%
Abercrombie & Fitch	1.2	%
IPG Photonics	1.0	%
Fugro	1.0	%
Polycom	0.8	%
Hansen Natural	0.8	%
Pacific Rubiales Energy	0.7	%
Oshkosh	0.5	%
SRA International	0.3	%

Columbia Acorn Fund rose 1.43% in the second quarter of 2011, outperforming the 0.59% drop in its primary benchmark, the Russell 2500 Index, and also beating other indexes shown on Page 1. During the first half of 2011, the Fund was up 7.18%, somewhat less than the Russell 2500's gain of 8.06%, and was mixed versus other indexes.

Consumer stocks were marked up during both the quarter and the half. Premium active apparel retailer lululemon athletica was the Fund's top dollar winner during both periods, up 26% in the quarter and 63% in the half. Alternative beverage producer Hansen Natural also provided large gains, rising 34% in the quarter and 55% in the half. Sales momentum at teen apparel retailer Abercrombie & Fitch accelerated, causing its stock to rack up a 14% gain in the quarter and a 16% gain in the half. All three companies had excellent growth in sales and earnings.

Several technology stocks also boosted results for the Fund. IPG Photonics, a company that is coupling laser and fiber optic technology, was Columbia Acorn Fund's second largest dollar gainer in both the quarter and the half, rising 26% and 130%, respectively. The company's quarterly earnings per share grew over six-fold on revenues that nearly doubled versus the prior year. Data integration software company Informatica rose 12% in the quarter and 33% in the half on fine earnings growth. Video conferencing equipment maker Polycom showed a 24% gain in the quarter and a 65% jump in the half on better than expected earnings.

Performance was boosted by takeovers. In the quarter, device maker American Medical Systems appreciated 39% as it agreed to be taken over by Endo Pharmaceuticals. Government I.T. services company SRA International agreed to sell out to a private equity firm, and its stock was up 51% in the half. GSI Commerce and Terremark were subject to takeover offers in the first quarter and their stocks also helped first half results.

The Fund's largest dollar loser in the quarter was sub-sea oilfield services provider Fugro, off 16% on disappointing earnings caused by customers delaying projects. Oshkosh fell 18% in the quarter, on news of a difficult start to military truck production. The Fund's largest dollar loser in the half was Colombian oil producer Pacific Rubiales Energy, off 21%. The stock gave up a fraction of its 2010 gains on exploration results that disappointed some analysts.

Columbia Acorn Fund's foreign stocks were off 3.59% in the quarter and 2.69% in the half.* Fugro and Pacific Rubiales Energy, mentioned above, were the largest foreign losers. The Fund's international stock weight dropped to 10.8% from 11.6% at the end of the first quarter and from 12.6% at the end of 2010.

The markets have been concerned about sovereign debt issues. While the U.S. debt ceiling was raised after the end of the quarter, the debt deal resulted in no fundamental reforms and large remaining uncertainties. A congressional committee will hopefully provide better solutions on schedule, before the end of 2011. The Greek debt situation seems more intractable, but the size of the debt is relatively small. Meanwhile, most of the companies owned by the Fund have been reporting fine earnings gains, which we believe could lead to higher stock prices should macroeconomic concerns ease.

*These returns are not comparable to mutual fund returns, as they are gross of fees and other expenses and do not portray the cash effects incurred by actual mutual funds. Columbia Acorn Fund's foreign stockholdings were not purchased as a balanced, stand-alone portfolio.

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 (ACRNX)

At a Glance

Performance data shown represents past performance and is not a guarantee of future results. The investment return and principal value of an investment will fluctuate so that shares, when redeemed, may be worth more or less than their original cost. Current performance may be lower or higher than the performance data shown. Performance results reflect any fee waivers or reimbursements of Fund expenses by the investment adviser and/or any of its affiliates. Absent these fee waivers and/or expense reimbursement arrangements, performance results would have been lower. Please visit columbiamanagement.com for daily and most recent month-end updates.

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

through June 30, 2011

Inception 6/10/70	Year to date*			1 year			5 years			10 years
Returns before taxes		7.18	%		39.46	%		6.19	%		9.21	%
Returns after taxes on distributions		6.92			38.52			5.49			8.66
Returns after taxes on distributions and sale of fund shares		4.86			26.57			5.23			8.07
Russell 2500 Index (pretax)**		8.06			39.28			5.20			7.40

All results shown assume reinvestment of distributions.

*Year to date data is not annualized

**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 0.76%.

Columbia Acorn Fund Portfolio Diversification

as a percentage of net assets, as of 6/30/11

Columbia Acorn Fund Top 10 Holdings

as a percentage of net assets, as of 6/30/11

1.	lululemon athletica Premium Active Apparel Retailer	2.3	%
2.	Ametek Aerospace/Industrial Instruments	1.6	%
3.	FMC Technologies Oil & Gas Wellhead Manufacturer	1.4	%
4.	Informatica Enterprise Data Integration Software	1.4	%
5.	Mettler Toledo Laboratory Equipment	1.4	%
6.	Donaldson Industrial Air Filtration	1.3	%
7.	Crown Castle International Communications Towers	1.3	%
8.	Abercrombie & Fitch Teen Apparel Retailer	1.2	%
9.	IPG Photonics Fiber Lasers	1.1	%
10.	Alexion Pharmaceuticals Biotech Focused on Orphan Diseases	1.0	%

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 Fund (Class Z)

June 10, 1970 through June 30, 2011

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: $19.3 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.

9

Columbia Acorn International

In a Nutshell

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

Performance data shown represents past performance and is not a 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. Current performance may be lower or higher than the performance data shown. Please visit columbiamanagement.com for daily and most recent month-end performance updates.

Fund's Positions
in Mentioned Holdings

As a percentage of net assets, as of 6/30/11

Melco Crown Entertainment	1.4	%
ShawCor	0.8	%
Simplo Technology	0.7	%
President Chain Store	0.5	%
Gree	0.5	%
Start Today	0.4	%
Petropavlovsk	0.4	%

Columbia Acorn International was up 1.70% in the second quarter of 2011, 0.98% ahead of its primary benchmark, the S&P Global Ex-U.S. Between $500M and $5B Index. This brought the Fund's return for the six months to 3.02%, slightly ahead of the 2.63% gain of its benchmark.

The Fund's absolute returns in the quarter were highest in Asia, driven by Melco Crown Entertainment, which operates a casino in Macau; Simplo Technology, a Taiwanese manufacturer of battery packs for notebook computers and iPads; and President Chain Store, a Taiwanese convenience store operator with inroads into mainland China. Consistent with the performance of these stocks, consumer discretionary and information technology sector holdings were the Fund's best performing globally. In a somewhat subdued quarter for international small-cap stocks overall, the Fund's Japanese holdings also put up a pleasing 5.9% USD return, led by two of the Fund's internet-related stocks: Gree, a social networking site and game developer, and Start Today, an online apparel retailer. These stocks were up over 30% and 28%, respectively, likely buoyed by high valuations assigned to U.S. internet-related businesses in recent public and private market transactions.

Energy and resource companies were among the most disappointing in the quarter. ShawCor was a big position and down 18% after reporting first quarter results substantially below expectations. This Canadian company makes money by coating pipelines, and the most profitable work tends to be large offshore projects, and those in Asia, the Middle East, and the North Sea. While the company is bidding on many new projects now, in recent quarters they unfortunately ran into a lull in large projects as work lined up two or three years ago came to an end. Petropavlovsk, a U.K.-domiciled gold and iron ore miner with mines in Russia, was off over 26% on investor worries that more delays and capital would be required to complete the company's projects. This came on top of general weakness among gold mining stocks.

Eurozone sovereign risk has recently been leading headlines. Europe, including countries not part of the common euro currency, is home to almost 40% of the Fund's assets. This is an overweight position, with risk mitigated and opportunity enhanced, we believe, by the fact that many of these European holdings have significant revenues and earnings outside of Europe. While we are not economists and do not structure the portfolio according to macroeconomic precepts, we expect the euro to survive the present crisis. We believe the protracted public debate reflects the inevitably messy process of allocating economic and political pain among creditor and debtor countries, and private and public actors. Indeed, creditor countries who seek tighter fiscal coordination among eurozone countries going forward have little to gain in ending the crisis until they have extracted such concessions. Markets, however, do not like uncertainty and continued volatility is likely until a solution is reached.

Thank you for your continued confidence in Columbia Acorn International.

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. 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 (ACINX)

At a Glance

Performance data shown represents past performance and is not a guarantee of future results. The investment return and principal value of an investment will fluctuate so that shares, when redeemed, may be worth more or less than their original cost. Current performance may be lower or higher than the performance data shown. Performance results reflect any fee waivers or reimbursements of Fund expenses by the investment adviser and/or any of its affiliates. Absent these fee waivers and/or expense reimbursement arrangements, performance results would have been lower. Please visit columbiamanagement.com for daily and most recent month-end updates.

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

through June 30, 2011

Inception 9/23/92	Year to date*			1 year			5 years			10 years
Returns before taxes		3.02	%		32.28	%		7.35	%		11.31	%
Returns after taxes on distributions		2.14			31.16			6.48			10.73
Returns after taxes on distributions and sale of fund shares		1.96			21.34			6.23			10.05
S&P Global Ex-U.S. Between $500M and $5B Index**		2.63			34.29			7.09			12.71

All results shown assume reinvestment of distributions.

*Year to date data is not annualized

**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 0.98%.

Columbia Acorn International Portfolio Diversification

as a percentage of net assets, as of 6/30/11

Columbia Acorn International Top 10 Holdings

as a percentage of net assets, as of 6/30/11

1.	Hexagon (Sweden) Measurement Equipment & Software	1.5	%
2.	Melco Crown Entertainment (Hong Kong) Macau Casino Operator	1.4	%
3.	Olam International (Singapore) Agriculture Supply Chain Manager	1.2	%
4.	Localiza Rent A Car (Brazil) Car Rental	1.2	%
5.	Kansai Paint (Japan) Paint Producer in Japan, India, China & Southeast Asia	1.1	%
6.	Zhaojin Mining Industry (China) Gold Mining & Refining in China	1.0	%
7.	Imtech (Netherlands) Electromechanical & Information & Communications Technologies Installation & Maintenance	1.0	%
8.	Intertek Group (United Kingdom) Testing, Inspection & Certification Services	1.0	%
9.	Naspers (South Africa) Media in Africa, China, Russia & Other Emerging Markets	1.0	%
10.	Fugro (Netherlands) Sub-sea Oilfield Services	0.9	%

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 June 30, 2011

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 $500M and $5B 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: $6.4 billion

11

Columbia Acorn USA

In a Nutshell

Robert A. Mohn

Lead Portfolio Manager

Performance data shown represents past performance and is not a 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. Current performance may be lower or higher than the performance data shown. Please visit columbiamanagement.com for daily and most recent month-end performance updates.

Fund's Positions
in Mentioned Holdings

As a percentage of net assets, as of 6/30/11

IPG Photonics	2.6	%
lululemon athletica	2.3	%
Gaylord Entertainment	1.3	%
Polycom	1.3	%
Cepheid	0.8	%
Diamond Foods	0.8	%
Finisar	0.7	%
Ixia	0.6	%
TriQuint Semiconductor	0.6	%

The equity markets were relatively flat in the second quarter of 2011. Columbia Acorn USA gained 1.50%, outperforming its primary benchmark, the Russell 2000 Index, which dropped 1.61%. Year to date through June 30, 2011, the Fund was up 9.14%, ahead of the 6.21% gain of its benchmark.

Winners for the quarter and half year came from a variety of sectors. IPG Photonics, a fiber laser manufacturer, dominates its market niche and nearly doubled sales versus the prior year. Its stock rose 26% in the quarter and ended the first six-months of 2011 up 130%. Premium active apparel retailer lululemon athletica also had strong revenue growth on ever-increasing awareness of the brand in the United States. The stock rose 26% in the quarter, and was up 63% for the half year. Polycom, a provider of video conferencing equipment, was up 24% in the quarter and finished the half year with a 65% return. The company's business benefited from increased corporate adoption of video conferencing as well as recent stumbles by a close competitor.

Diamond Foods, a provider of nuts and snack foods, announced an agreement to purchase the Pringles brand from Procter & Gamble, a move that will transform Diamond into the second largest snack company in the world, behind Pepsi. The stock rose 37% in the quarter on the news and was up 44% for the half year. Cepheid, a provider of molecular diagnostic equipment, experienced strong sales of its automated genetic testing instruments, which helped drive its stock up 24% in the quarter and 52% for the half year.

On the downside, two names in the optical network equipment business fell due to revenue shortfalls. Finisar, a provider of optical sub-systems and components, was a big winner for the Fund last year but orders have slowed in 2011, leaving Finisar customers with excess inventory. Its stock was off 27% in the quarter and 39% for the six months. Ixia sells telecom test equipment for optical networks and also suffered from a drop in orders. The company's stock fell 19% in the quarter and 22% for the half year.

TriQuint Semiconductor, a manufacturer of radio frequency semiconductors for mobile phones and other wireless devices, disappointed as some handset manufacturers deferred new product launches, sending the company's stock down 21% in the quarter and 17% for the half year. Gaylord Entertainment, an owner of convention hotels, was hurt by a drop in the occupancy rate at its Washington DC hotel, sending the stock down 13% for the quarter and 17% for the half year.

These days, many investors are obsessing over a seeming epidemic of ominous macroeconomic troubles and their potential solutions. Scary stuff like national debt crises, Mediterranean defaults, stubbornly high unemployment, and double-dipping housing prices dominate the news. But we believe that these issues are not as relevant to our philosophy of investing. We don't subscribe to the current fetish of investing based on macroeconomic factors (commonly referred to as "risk-on, risk-off" trading). Even in volatile, uncertain times like today, plenty of individual smaller cap companies are growing faster than their peers and possess bright long-term prospects. We spend our time and effort seeking out these kinds of businesses for your Fund. We'll leave the macro-dancing to the other guys.

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 (AUSAX)

At a Glance

Performance data shown represents past performance and is not a guarantee of future results. The investment return and principal value of an investment will fluctuate so that shares, when redeemed, may be worth more or less than their original cost. Current performance may be lower or higher than the performance data shown. Performance results reflect any fee waivers or reimbursements of Fund expenses by the investment adviser and/or any of its affiliates. Absent these fee waivers and/or expense reimbursement arrangements, performance results would have been lower. Please visit columbiamanagement.com for daily and most recent month-end updates.

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

through June 30, 2011

Inception 9/4/96	Year to date*			1 year			5 years			10 years
Returns before taxes		9.14	%		43.38	%		4.85	%		7.19	%
Returns after taxes on distributions		9.14			43.38			4.50			6.87
Returns after taxes on distributions and sale of fund shares		5.94			28.19			4.13			6.28
Russell 2000 Index (pretax)**		6.21			37.41			4.08			6.27

All results shown assume reinvestment of distributions.

*Year to date data is not annualized

**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 1.01%.

Columbia Acorn USA Portfolio Diversification

as a percentage of net assets, as of 6/30/11

Columbia Acorn USA Top 10 Holdings

as a percentage of net assets, as of 6/30/11

1.	Informatica Enterprise Data Integration Software	3.0	%
2.	IPG Photonics Fiber Lasers	2.6	%
3.	FMC Technologies Oil & Gas Wellhead Manufacturer	2.3	%
4.	lululemon athletica Premium Active Apparel Retailer	2.3	%
5.	Ametek Aerospace/Industrial Instruments	2.2	%
6.	Nordson Dispensing Systems for Adhesives & Coatings	2.1	%
7.	Atwood Oceanics Offshore Drilling Contractor	1.9	%
8.	Micros Systems Information Systems for Hotels, Restaurants & Retailers	1.8	%
9.	tw telecom Fiber Optic Telephone/Data Services	1.7	%
10.	II-VI Laser Optics & Specialty Materials	1.7	%

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 June 30, 2011

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: $1.9 billion

13

Columbia Acorn International Select

In a Nutshell

Christopher J. Olson

Lead Portfolio Manager

Performance data shown represents past performance and is not a 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. Current performance may be lower or higher than the performance data shown. Please visit columbiamanagement.com for daily and most recent month-end performance updates.

Fund's Positions
in Mentioned Holdings

As a percentage of net assets, as of 6/30/11

Ascendas REIT	5.0	%
Hexagon	3.7	%
Wirecard	2.7	%
Asahi Diamond Industrial	2.4	%
Jupiter Telecommunications	2.2	%
Fugro	1.9	%
United Drug	1.9	%
Pacific Rubiales Energy	1.6	%
Jiangsu Expressway	1.4	%
Gree	1.4	%
Workspace Group	1.1	%
Quetzal Energy	0.3	%

Columbia Acorn International Select ended the second quarter up 1.10%, outperforming the 0.90% gain of its primary benchmark, the S&P Developed Ex-U.S. Between $2B and $10B Index. For the half year, the Fund was up 3.74% versus a 4.04% gain for the benchmark.

The Fund's top three contributors to performance for the quarter were Japanese stocks, as the economic situation in Japan began to stabilize and recover following the March 2011 Tohoku earthquake. Gree, a mobile social networking game developer, was up 32% in the second quarter and 78% for the half year. The company continued to benefit from new product rollouts. Asahi Diamond Industrial, a manufacturer of consumable diamond tools, was up 14% in the quarter and ended the half year with a 16% gain. Its operations were largely unaffected by the earthquake and its revenues remained strong. Jupiter Telecommunications, the largest cable service provider in Japan, had a 15% gain in the quarter on continued subscriber growth. The majority of its operations are in the Tokyo region.

Elsewhere, Ascendas REIT, an industrial property landlord in Singapore, is a large position in the Fund and was up 6% for the quarter and the half year. The company continues to report rental rate increases on strong demand for its properties and its 7% dividend yield has attracted attention in a world of low interest rates. Swedish measurement equipment manufacturer Hexagon continued its strong run, gaining 4% in the quarter and ending the half year up 16%. The company has benefited from continued revenue growth driven mainly by its exposure to emerging markets.

Year to date, German online payment processor and risk manager Wirecard was up 32%. The company is growing revenues at a 20% clip on the back of ongoing growth of e-commerce as well as the introduction of a popular prepaid cash card. Irish pharmaceutical company United Drug rose 21% as investors realized earnings had improved and the stock was very cheap. Workspace Group, a UK real estate company, was up 29% for the half year, benefiting from improving occupancy rates.

Energy stocks dominated the laggards list for the quarter and half. After many quarters of strong performance, Dutch sub-sea oilfield services provider Fugro fell more than 16% in the quarter and was off 11% for the half year. The company reported disappointing earnings, stating that many of its customers opted to delay expected projects. Quetzal Energy, an oil and gas exploration company operating in Latin America, fell 44% in the quarter and was down 37% for the half as a delay in receiving environmental approvals slowed down its drilling program. Pacific Rubiales Energy, a Colombian oil production and exploration company, was off 3% in the quarter and down 21% for the half year on disappointing results from recent explorations.

Outside the energy sector, Petropavlovsk, a UK-listed company operating gold and iron ore mines in Russia, fell 15% in the quarter and was off 24% in Columbia Acorn International Select for the half year. Delays and capital concerns, combined with weakness in gold mining stocks in general, hurt returns. We sold the Fund's position in the stock. Jiangsu Expressway, a Chinese toll road operator, fell 13% in the quarter and was off 15% for the half after the government began to crack down on toll operators who were overcharging. Jiangsu Expressway has kept its charges in line with stated policy but was down nonetheless, as the entire sector was sold off.

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. 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 (ACFFX)

At a Glance

Performance data shown represents past performance and is not a guarantee of future results. The investment return and principal value of an investment will fluctuate so that shares, when redeemed, may be worth more or less than their original cost. Current performance may be lower or higher than the performance data shown. Performance results reflect any fee waivers or reimbursements of Fund expenses by the investment adviser and/or any of its affiliates. Absent these fee waivers and/or expense reimbursement arrangements, performance results would have been lower. Please visit columbiamanagement.com for daily and most recent month-end updates.

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

through June 30, 2011

Inception 11/23/98	Year to date*			1 year			5 years			10 years
Returns before taxes		3.74	%		31.33	%		7.22	%		9.50	%
Returns after taxes on distributions		3.24			30.81			6.82			9.30
Returns after taxes on distributions and sale of fund shares		2.44			20.49			6.23			8.49
S&P Developed Ex-U.S. Between $2B and $10B Index (pretax)**		4.04			33.74			3.73			9.60

All results shown assume reinvestment of distributions.

*Year to date data is not annualized

**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 1.16%.

Columbia Acorn International Select Portfolio Diversification

as a percentage of net assets, as of 6/30/11

Columbia Acorn International Select Top 10 Holdings

as a percentage of net assets, as of 6/30/11

1.	Ascendas REIT (Singapore) Singapore Industrial Property Landlord	5.0	%
2.	Kansai Paint (Japan) Paint Producer in Japan, India, China & Southeast Asia	4.4	%
3.	Chemring (United Kingdom) Defense Manufacturer of Countermeasures & Energetics	3.8	%
4.	Hexagon (Sweden) Measurement Equipment & Software	3.7	%
5.	NHN (South Korea) South Korea's Largest Online Search Engine	3.2	%
6.	Mapletree Industrial Trust (Singapore) Industrial Property Landlord	3.2	%
7.	Intertek Group (United Kingdom) Testing, Inspection & Certification Services	2.9	%
8.	Wirecard (Germany) Online Payment Processing & Risk Management	2.7	%
9.	Asahi Diamond Industrial (Japan) Consumable Diamond Tools	2.4	%
10.	AkzoNobel (Netherlands) Largest Global Supplier of Protective Paints & Coatings	2.4	%

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 June 30, 2011

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 $2B and $10B 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: $437.3 million

15

Columbia Acorn Select

In a Nutshell

Ben Andrews	Robert A. Chalupnik
Lead Portfolio Manager	Co-Portfolio Manager

Performance data shown represents past performance and is not a 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. Current performance may be lower or higher than the performance data shown. Please visit columbiamanagement.com for daily and most recent month-end performance updates.

Fund's Positions
in Mentioned Holdings

As a percentage of net assets, as of 6/30/11

Discover Financial Services	6.6	%
Abercrombie & Fitch	3.6	%
Coach	3.2	%
Canacol Energy	1.9	%
Quanta Services	1.4	%
Gaylord Entertainment	1.3	%
Finisar	0.3	%

Columbia Acorn Select fell 0.95% in the second quarter of 2011 and was nearly flat for the half year, up 0.02%. The Fund's primary benchmark, the S&P MidCap 400 Index, was down 0.73% in the second quarter and up 8.56% for the six months ended June 30, 2011. The large-cap oriented S&P 500 Index was flat in the second quarter (up 0.10%) and was up 6.02% for the half year. Year-to-date performance was hampered by poor performance of Fund energy stocks and the failure of many holdings to participate in the recent market rally.

Looking first at the stocks that drove the portfolio in the second quarter, Discover Financial Services added 0.77% to the portfolio's return as the company's credit card portfolio continued to heal in the improving economy. This improvement caused investors to increase the valuation they were willing to pay for Discover, bidding up the stock price. Retailers Abercrombie & Fitch and Coach each added approximately 0.60% to the portfolio as their products were well received by consumers.

On the downside, Canacol Energy, an oil and gas explorer/producer, cost the portfolio 0.66% as an exploratory well in Guyana came up dry and the general malaise for Colombian oil producers weighed on the stock. Over the six-month period, energy stocks cost the Fund approximately 3.7% of performance, and were the main laggards in the portfolio. We still believe in these names and will watch them closely as we expect several more drilling results by the end of this year.

Though many of the Fund's stocks did not participate in the stock market rally through June 30, 2011, we believe they have potential to add return in the coming quarters as these companies are growing and we believe they are valued inexpensively compared with their peers.

During the quarter, we sold out of four companies and purchased three new companies. The sales were wireless communications and broadcast tower company American Tower, water treatment applications service provider Nalco Holding Company, for-profit, post-secondary education provider Career Education, and recreational vehicle manufacturer Thor Industries. Our purchases were convention hotelier Gaylord Entertainment, fiber optic sub-systems and components provider Finisar, and electrical and telecom construction services provider Quanta Services. Quanta is a company that we owned previously but sold due to uncertainty about its ability to turn contracts/backlog into sales. There is evidence of this backlog becoming revenue, so we added the company back into the portfolio during the quarter.

I would like to welcome Rob Chalupnik as co-portfolio manager of Columbia Acorn Select. Rob has a strong track record as the domestic industrials analyst at Columbia Wanger Asset Management. I have worked closely with Rob over the years and feel strongly that his knowledge and ability will be additive to the performance of this Fund, not only through his stock picks but through his input on portfolio structure as well.

Thank you for your continued investment in Columbia Acorn Select.

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 (ACTWX)

At a Glance

Performance data shown represents past performance and is not a guarantee of future results. The investment return and principal value of an investment will fluctuate so that shares, when redeemed, may be worth more or less than their original cost. Current performance may be lower or higher than the performance data shown. Performance results reflect any fee waivers or reimbursements of Fund expenses by the investment adviser and/or any of its affiliates. Absent these fee waivers and/or expense reimbursement arrangements, performance results would have been lower. Please visit columbiamanagement.com for daily and most recent month-end updates.

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

through June 30, 2011

Inception 11/23/98	Year to date*			1 year			5 years			10 years
Returns before taxes		0.02	%		29.03	%		5.17	%		8.41	%
Returns after taxes on distributions		-0.57			28.27			4.84			8.13
Returns after taxes on distributions and sale of fund shares		-0.01			18.85			4.37			7.39
S&P MidCap 400 Index (pretax)**		8.56			39.38			6.60			7.94

All results shown assume reinvestment of distributions.

*Year to date data is not annualized

**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 0.97%.

Columbia Acorn Select Portfolio Diversification

as a percentage of net assets, as of 6/30/11

Columbia Acorn Select Top 10 Holdings

as a percentage of net assets, as of 6/30/11

1.	Discover Financial Services Credit Card Company	6.8	%
2.	Hertz Largest U.S. Rental Car Operator	6.5	%
3.	CNO Financial Group Life, Long-term Care & Medical Supplement Insurance	4.8	%
4.	Ametek Aerospace/Industrial Instruments	4.0	%
5.	Abercrombie & Fitch Teen Apparel Retailer	3.6	%
6.	Sanmina-SCI Electronic Manufacturing Services	3.5	%
7.	Safeway Supermarkets	3.4	%
8.	Pacific Rubiales Energy (Colombia) Oil Production & Exploration in Colombia	3.3	%
9.	Coach Designer & Retailer of Branded Leather Accessories	3.2	%
10.	Crown Castle International Communications Towers	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 June 30, 2011

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: $2.0 billion

17

Columbia Thermostat Fund

In a Nutshell

Charles P. McQuaid

Lead Portfolio Manager

Performance data shown represents past performance and is not a 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. Current performance may be lower or higher than the performance data shown. Please visit columbiamanagement.com for daily and most recent month-end performance updates.

A "fund of fund" 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 gained 1.47% in the second quarter of 2011, outperforming the 0.10% gain of its primary equity benchmark, the S&P 500 Index, and underperforming the 2.29% increase of the Fund's primary debt benchmark, the Barclays Capital U.S. Aggregate Bond Index. Year to date through June 30, 2011, the Fund was up 4.66% while the S&P 500 Index had a 6.02% gain and the Barclays index rose 2.72%.

The Fund hit four reallocation triggers during the second quarter. In April, we reduced stock exposure twice on the strength of the equity market and then in May and June returned to stocks as the equity markets declined. The Fund ended the quarter at the same weight it started, with a 60% exposure to its underlying stock funds and 40% exposure to its bond funds.

The bond portion of the portfolio outperformed the equity portion in the quarter with a 1.50% weighted average return versus a 0.93% weighted average gain for equities. Columbia U.S. Treasury Index Fund was the top performing holding for the quarter, up 2.28%. Year to date, Columbia Thermostat's equity portion had a 5.22% weighted average gain versus a 2.83% gain for the income portion. Columbia Large Cap Enhanced Core Fund led performance with a 7.90% gain for the half-year period.

The markets continue to provide the types of ups and downs that Columbia Thermostat Fund was made for. We are pleased to see that the Fund, as expected, provided a return between that of its equity and income benchmarks for the six-month period.

Results of the Funds Owned in Columbia Thermostat Fund as of June 30, 2011

Stock Funds	Weightings			2nd			Year to
Fund	in category			quarter			date
Columbia Acorn International, Class I		20	%		1.69	%		3.06	%
Columbia Dividend Income Fund, Class I		20	%		0.83	%		6.07	%
Columbia Acorn Fund, Class I		15	%		1.47	%		7.22	%
Columbia Marsico Growth Fund, Class I		15	%		0.87	%		6.29	%
Columbia Acorn Select, Class I		10	%		-0.93	%		0.04	%
Columbia Contrarian Core Fund, Class I		10	%		0.60	%		5.66	%
Columbia Large Cap Enhanced Core Fund, Class I		10	%		0.94	%		7.90	%
Weighted Average Equity Return		100	%		0.93	%		5.22	%
Bond Funds	Weightings			2nd			Year
Fund	in category			quarter			to date
Columbia Intermediate Bond Fund, Class I		50	%		1.29	%		2.64	%
Columbia U.S. Treasury Index Fund, Class I		30	%		2.28	%		2.03	%
Columbia Income Opportunities Fund, Class I		20	%		0.82	%		4.39	%
Weighted Average Income Return		100	%		1.50	%		2.83	%

Columbia Thermostat Fund
Rebalancing in the Second Quarter

April 11, 2011	55% stocks, 45% bonds
April 28, 2011	50% stocks, 50% bonds
May 31, 2011	55% stocks, 45% bonds
June 7, 2011	60% stocks, 40% bonds

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 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. 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 (COTZX)

At a Glance

Performance data shown represents past performance and is not a guarantee of future results. The investment return and principal value of an investment will fluctuate so that shares, when redeemed, may be worth more or less than their original cost. Current performance may be lower or higher than the performance data shown. Performance results reflect any fee waivers or reimbursements of Fund expenses by the investment adviser and/or any of its affiliates. Absent these fee waivers and/or expense reimbursement arrangements, performance results would have been lower. Please visit columbiamanagement.com for daily and most recent month-end updates.

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

through June 30, 2011

Inception 9/25/02	Year to date*			1 year			5 years			Life of fund
Returns before taxes		4.66	%		25.39	%		5.81	%		7.94	%
Returns after taxes on distributions		4.21			24.75			4.46			6.68
Returns after taxes on distributions and sale of fund shares		3.02			16.62			4.34			6.35
S&P 500 Index (pretax)**		6.02			30.69			2.94			7.72
Barclays Capital U.S. Aggregate Bond Index (pretax)**		2.72			3.90			6.52			5.06
Lipper Flexible Portfolio Funds Index (pretax)		5.11			23.38			5.16			8.28

All results shown assume reinvestment of distributions.

*Year to date data is not annualized

**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, 2012. Expense ratios without and with the contractual waiver, including fees and expenses associated with the Fund's investment in other investment companies, are 1.16% and 1.04%, 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 6/30/11

Columbia Thermostat Fund Portfolio Weightings

as a percentage of assets in each investment category, as of 6/30/11

Stock Mutual Funds

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

Bond Mutual Funds

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

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

September 25, 2002 through June 30, 2011

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. 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 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: $137.9 million

19

Columbia Acorn Fund

Major Portfolio Changes in the Second Quarter (Unaudited)

	Number of Shares
	03/31/11		06/30/11
Purchases
Information
ANSYS		2,100,000		2,550,000
Boingo Wireless		0		1,200,000
Constant Contact		1,919,615		1,950,000
ExlService Holdings		1,045,000		1,145,000
Genpact		0		781,635
IMAX (Canada)		800,000		1,400,000
Intralinks		0		550,000
Ixia		1,720,000		2,030,000
ON Semiconductor		3,440,000		5,117,000
Polycom		2,305,000		2,455,000
Syntel		0		580,000
TIBCO		0		1,381,600
Verisk Analytics		450,000		900,000
Virtusa		2,064,900		2,125,000
WMS Industries		1,150,000		2,100,000
WNS - ADR (India)		1,000,000		1,027,147
Consumer Goods & Services
Cavco Industries		388,907		415,000
HomeAway		0		1,289,880
MGM China Holdings (Hong Kong)		0		12,000,000
P.F. Chang's China Bistro		300,000		480,000
Phillips-Van Heusen		1,055,000		1,410,000
Thor Industries		1,190,000		1,980,000
Industrial Goods & Services
Albemarle		1,575,972		1,650,000
Imtech (Netherlands)		1,731,432		1,767,165
Kennametal		2,625,000		2,900,000
LKQ		450,000		900,000
Pentair		3,350,000		3,535,000
Quanta Services		1,950,000		2,800,000
Ushio (Japan)		1,322,000		1,500,000
Valmont Industries		0		100,000
Energy & Minerals
Alexco Resource		2,400,000		2,800,000
Celtic Exploration (Canada)		0		175,400
Crew Energy (Canada)		0		484,500
Fugro (Netherlands)		2,570,626		2,641,054
Oil States International		463,954		743,000
Primary Petroleum (Canada)		0		2,245,000
Silver Standard Resources		800,000		900,000
Swift Energy		275,000		550,000
Wolverine Minerals (Canada)		0		4,000,000
Finance
Alliance Data Systems		275,000		400,000
Assured Guaranty		0		300,000
City National		1,045,000		1,145,000

	Number of Shares
	03/31/11		06/30/11
Enstar Group		0		33,746
Financial Engines		0		400,000
First Busey		3,299,507		4,056,427
Health Care
Adcock Ingram Holdings (South Africa)		2,259,000		2,393,955
Akorn		3,733,354		4,000,000
Alimera Sciences		855,298		1,818,154
Anthera Pharmaceuticals		1,450,000		1,740,000
Auxilium Pharmaceuticals		1,200,000		2,400,000
Community Health Systems		1,380,000		1,655,000
InterMune		1,731,000		2,226,000
Kindred Healthcare		0		1,450,000
Nabi Biopharmaceuticals		2,611,936		3,300,000
United Therapeutics		510,000		780,000
Other Industries
Associated Estates Realty		2,200,000		2,700,000
Genesee & Wyoming		100,000		400,000
St. Joe		0		699,701
Summit Hotel Properties		1,092,000		1,481,994

See accompanying notes to financial statements.

20

	Number of Shares
	03/31/11		06/30/11
Sales
Information
AboveNet		1,265,000		1,199,876
Blue Coat Systems		1,260,000		313,300
Crown Castle International		6,300,000		6,000,000
Dionex		300,000		0
Dolby Laboratories		1,140,000		815,000
Hexagon (Sweden)		5,914,999		5,164,999
Informatica		5,200,000		4,700,000
NetSuite		1,800,000		1,450,000
Plexus		1,490,000		1,210,000
SRA International		1,655,000		1,583,750
THQ		3,567,000		0
Consumer Goods & Services
Blue Nile		180,000		62,784
Chico's FAS		2,562,000		1,933,750
CTS Eventim (Germany)		220,000		173,436
Diamond Foods		1,300,000		1,170,000
Hansen Natural		2,200,000		1,900,000
ITT Educational Services		1,080,000		350,000
lululemon athletica		4,035,000		3,991,265
Talbots		4,150,000		828,500
Industrial Goods & Services
American Reprographics		900,000		0
Lumber Liquidators		700,000		0
Mersen (France)		753,000		524,000
Mine Safety Appliances		1,525,000		1,300,000
Mueller Water Products		1,750,000		649,641
Nalco		1,800,000		831,000
Serco (United Kingdom)		2,559,000		0
Simpson Manufacturing		700,000		360,073
Energy & Minerals
Atwood Oceanics		3,200,000		2,399,000
Carrizo Oil & Gas		583,000		293,000
Gran Tierra Energy (Colombia)		3,131,195		0
Pan American Silver (Canada)		500,000		0
Synthesis Energy Systems (China)		1,726,270		1,210,300
Tesco		1,750,000		0
Vaalco Energy		750,000		0
Finance
CAI International		1,450,000		1,123,400
GATX		1,480,000		90,020
Housing Development Finance (India)		1,300,000		0
Investment Technology Group		697,000		629,493
SVB Financial Group		1,260,000		1,160,000
TCF Financial		4,150,000		3,613,000
Wilmington Trust		2,640,000		0

	Number of Shares
	03/31/11		06/30/11
Health Care
Allos Therapeutics		2,755,534		0
American Medical Systems		3,150,000		0
AthenaHealth		500,000		0
Gen-Probe		1,065,000		700,000
Idenix Pharmaceuticals		2,682,497		2,300,000
Nanosphere		964,499		0
Nektar Therapeutics		1,091,990		0
Savient Pharmaceuticals		1,700,000		0
United Drug (Ireland)		826,526		0

See accompanying notes to financial statements.

21

Columbia Acorn Fund

Statement of Investments (Unaudited), June 30, 2011

Number of Shares			Value (000)
			Equities: 97.5%
Information 27.2%
		> Business Software 6.6%
	4,700,000	Informatica (a)	$	274,621
		Enterprise Data Integration Software
	2,550,000	ANSYS (a)		139,408
		Simulation Software for Engineers & Designers
	2,700,000	Micros Systems (a)		134,217
		Information Systems for Hotels, Restaurants & Retailers
	1,100,000	Quality Systems		96,030
		IT Systems for Medical Groups & Ambulatory Care Centers
	1,480,000	Concur Technologies (a)		74,104
		Web Enabled Cost & Expense Management Software
	1,700,000	Blackboard (a)(b)		73,763
		Education Software
	2,250,000	Blackbaud (c)		62,370
		Software & Services for Non-profits
	1,450,000	NetSuite (a)(b)		56,840
		End to End IT Systems Solutions Delivered Over the Web
	2,000,000	Tyler Technologies (a)(c)		53,560
		Financial, Tax, Court & Document Management Systems for Local Governments
	1,950,000	Constant Contact (a)(b)(c)		49,491
		E-mail & Other Marketing Campaign Management Systems Delivered Over the Web
	2,025,000	Kenexa (a)(c)		48,560
		Recruiting & Workforce Management Solutions
	1,200,000	Ariba (a)		41,364
		Cost Management Software
	1,381,600	TIBCO (a)		40,094
		Datacenter Software
	850,000	Red Hat (a)		39,015
		Maintenance & Support for Open Source & Middleware
	920,000	Jack Henry & Associates		27,609
		Systems Financial Institutions
	690,000	Advent Software (a)		19,437
		Asset Management & Trading Systems
	900,000	SPS Commerce (a)(c)		16,011
		Supply Chain Management Software Delivered via the Web
	550,000	Intralinks (a)		9,504
		Collaboration Software
	1,500,000	Actuate (a)		8,775
		Information Delivery Software & Solutions
	1,000,000	InContact (a)		4,750
		Call Center Systems Delivered via the Web & Telecommunications Services
				1,269,523
		> Instrumentation 3.7%
	1,600,000	Mettler Toledo (a)		269,872
		Laboratory Equipment
	2,780,000	IPG Photonics (a)(c)		202,134
		Fiber Lasers

Number of Shares			Value (000)
	5,164,999	Hexagon (Sweden)	$	127,222
		Measurement Equipment & Software
	2,035,000	Trimble Navigation (a)		80,667
		GPS-based Instruments
	600,000	FLIR Systems		20,226
		Infrared Cameras
	400,000	Hamamatsu Photonics (Japan)		17,295
		Optical Sensors for Medical & Industrial Applications
				717,416
		> Computer Hardware & Related Equipment 2.7%
	3,565,000	Amphenol		192,474
		Electronic Connectors
	4,550,000	II-VI (a)(c)		116,480
		Laser Optics & Specialty Materials
	1,605,000	Zebra Technologies (a)		67,683
		Bar Code Printers
	1,200,000	Netgear (a)		52,464
		Networking Products for Small Business & Home
	815,000	Dolby Laboratories (a)		34,605
		Audio Technology for Consumer Electronics
	800,000	Nice Systems - ADR (Israel) (a)		29,088
		Audio & Video Recording Solutions
	605,000	Stratasys (a)		20,389
		Rapid Prototyping Systems
				513,183
		> Semiconductors & Related Equipment 2.1%
	8,130,000	Atmel (a)		114,389
		Microcontrollers, Radio Frequency & Memory Semiconductors
	5,117,000	ON Semiconductor (a)		53,575
		Mixed-signal & Power Management Semiconductors
	5,000,000	Entegris (a)		50,600
		Semiconductor Materials Management Products
	2,345,000	Microsemi (a)		48,072
		Analog/Mixed-signal Semiconductors
	500,000	Littelfuse		29,360
		Little Fuses
	1,900,000	IXYS (a)(c)		28,462
		Power Semiconductors
	935,000	Supertex (a)(c)		20,944
		Analog/Mixed-signal Semiconductors
	1,750,000	TriQuint Semiconductor (a)		17,833
		Radio Frequency Semiconductors
	1,765,000	Pericom Semiconductor (a)(c)		15,779
		Interface Integrated Circuits (ICs) & Frequency Control Products
	1,650,000	Applied Micro Circuits (a)		14,619
		Communications Semiconductors
	800,000	Monolithic Power Systems (a)		12,336
		High Performance Analog & Mixed-signal Integrated Circuits (ICs)
				405,969

See accompanying notes to financial statements.

22

Number of Shares			Value (000)
		> Telephone and Data Services 2.1%
	9,500,000	tw telecom (a)(c)	$	195,035
		Fiber Optic Telephone/Data Services
	1,199,876	AboveNet		84,543
		Metropolitan Fiber Communications Services
	9,600,000	PAETEC Holding (a)(c)		45,984
		Telephone/Data Services for Business
	2,520,000	Cogent Communications (a)(c)		42,865
		Internet Data Pipelines
	2,000,000	General Communications (a)		24,140
		Commercial Communications & Consumer CATV, Web & Phone in Alaska
	1,200,000	Boingo Wireless (a)(b)		10,896
		Wholesale & Retail WiFi Networks
				403,463
		> Mobile Communications 2.0%
	6,000,000	Crown Castle International (a)		244,740
		Communications Towers
	3,150,000	SBA Communications (a)		120,298
		Communications Towers
	1,000,000	MetroPCS Communications (a)		17,210
		Discount Cellular Telephone Services
	1,500,000	Globalstar (a)(b)		1,845
		Satellite Mobile Voice & Data Carrier
				384,093
		> Telecommunications Equipment 1.6%
	2,455,000	Polycom (a)		157,856
		Video Conferencing Equipment
	685,000	F5 Networks (a)		75,521
		Internet Traffic Management Equipment
	1,725,000	Finisar (a)		31,102
		Optical Sub-systems & Components
	2,030,000	Ixia (a)		25,984
		Telecom Network Test Equipment
	1,925,000	Infinera (a)		13,302
		Optical Networking Equipment
	313,300	Blue Coat Systems (a)		6,849
		WAN Acceleration & Network Security
				310,614
		> Computer Services 1.4%
	1,583,750	SRA International (a)		48,970
		Government IT Services
	2,900,000	iGate (b)(c)		47,328
		IT & BPO (Business Process Outsourcing) Services
	2,125,000	Virtusa (a)(c)		40,269
		Offshore IT Outsourcing
	580,000	Syntel		34,290
		Offshore I/T Services
	1,145,000	ExlService Holdings (a)		26,449
		BPO (Business Process Outsourcing)
	4,500,000	Hackett Group (a)(c)		22,905
		IT Integration & Best Practice Research
	1,560,000	Acxiom (a)		20,452
		Database Marketing Services
	781,635	Genpact (a)		13,475
		Business Process Outsourcing

Number of Shares			Value (000)
	1,027,147	WNS - ADR (India) (a)	$	9,131
		Offshore BPO (Business Process Outsourcing) Services
				263,269
		> Gaming Equipment & Services 1.1%
	3,725,000	Bally Technologies (a)(b)(c)		151,533
		Slot Machines & Software
	2,100,000	WMS Industries (a)		64,512
		Slot Machine Provider
				216,045
		> CATV 1.0%
	3,000,000	Discovery Communications, Series C (a)		109,650
		Cable TV Programming
	1,250,000	Liberty Global, Series A (a)(b)		56,300
		Cable TV Franchises Outside the USA
	17,770	Jupiter Telecommunications (Japan)		19,881
		Largest Cable Service Provider in Japan
				185,831
		> Financial Processors 0.9%
	2,429,000	Global Payments		123,879
		Credit Card Processor
	5,000,000	Singapore Exchange (Singapore)		30,725
		Singapore Equity & Derivatives Market Operator
	750,000	Hong Kong Exchanges and Clearing (Hong Kong)		15,802
		Hong Kong Equity & Derivatives Market Operator
				170,406
		> Electronics Distribution 0.5%
	3,125,000	Avnet (a)		99,625
		Electronic Components Distribution
				99,625
		> Business Information & Marketing Services 0.5%
	900,000	FTI Consulting (a)(b)		34,146
		Financial Consulting Firm
	3,100,000	Navigant Consulting (a)(c)		32,519
		Financial Consulting Firm
	900,000	Verisk Analytics (a)		31,158
		Risk & Decision Analytics
				97,823
		> Contract Manufacturing 0.4%
	1,210,000	Plexus (a)		42,120
		Electronic Manufacturing Services
	2,800,000	Sanmina-SCI (a)		28,924
		Electronic Manufacturing Services
				71,044
		> Internet Related 0.3%
	435,000	Equinix (a)		43,944
		Network Neutral Data Centers
	464,305	Mail.ru - GDR (Russia) (a)(d)		15,424
		Internet Social Networking & Games for Russian Speakers
	1,000,000	TheStreet.com		3,070
		Financial Information Websites
				62,438

See accompanying notes to financial statements.

23

Columbia Acorn Fund

Statement of Investments (Unaudited), continued

Number of Shares			Value (000)
		> Entertainment Programming 0.2%
	1,400,000	IMAX (Canada) (a)	$	45,402
		IMAX Movies, Theatre Equipment & Theatre Joint Ventures
				45,402
		> Radio 0.1%
	164,991	Saga Communications (a)		6,105
		Radio Stations in Small & Mid-sized Cities
	1,541,000	Salem Communications (c)		5,532
		Radio Stations for Religious Programming
	2,400,000	Spanish Broadcasting System (a)(c)		1,680
		Spanish Language Radio Stations
				13,317
		> TV Broadcasting —%
	2,500,000	Entravision Communications (a)		4,625
		Spanish Language TV & Radio Stations
	1,750,000	Gray Television (a)(b)		4,620
		Mid-market Affiliated TV Stations
				9,245
		> Advertising —%
	1,500,000	VisionChina Media - ADR (China) (a)(b)		4,245
		Advertising on Digital Screens in China's Mass Transit System
				4,245
Information: Total				5,242,951
Consumer Goods & Services 18.3%
		> Retail 5.2%
	3,991,265	lululemon athletica (a)(c)		446,304
		Premium Active Apparel Retailer
	3,510,000	Abercrombie & Fitch		234,889
		Teen Apparel Retailer
	2,300,000	Shutterfly (a)(c)		132,066
		Internet Photo-centric Retailer
	5,600,000	Pier 1 Imports (a)		64,792
		Home Furnishing Retailer
	5,225,000	Saks (a)		58,363
		Luxury Department Store Retailer
	1,933,750	Chico's FAS		29,451
		Women's Specialty Retailer
	525,000	DSW (a)		26,570
		Branded Footwear Retailer
	1,371,366	Gaiam (c)		6,816
		Healthy Living Catalogs & E-Commerce
	828,500	Talbots (a)(b)		2,767
		Women's Specialty Retailer
	62,784	Blue Nile (a)(b)		2,761
		Online Jewelry Retailer
	66,000	The Fresh Market (a)		2,553
		Specialty Food Retailer
				1,007,332
		> Apparel 3.5%
	2,100,000	Coach		134,253
		Designer & Retailer of Branded Leather Accessories

Number of Shares			Value (000)
	2,190,000	Warnaco Group (a)	$	114,427
		Global Branded Apparel Manufacturer
	1,120,000	Deckers Outdoor (a)		98,717
		Fashion Footwear Wholesaler
	1,410,000	Phillips-Van Heusen		92,313
		Apparel Wholesaler & Retailer
	1,980,000	Guess?		83,279
		Branded Apparel, Accessories & Licensor
	2,047,000	True Religion Apparel (a)(c)		59,527
		Premium Denim
	1,400,000	Crocs (a)		36,050
		Branded Footwear Wholesaler & Retailer
	1,000,000	Hanesbrands (a)		28,550
		Apparel Wholesaler
	600,000	Steven Madden (a)		22,506
		Wholesaler/Retailer of Fashion Footwear
	100,197	Zuoan Fashion (China) (a)(b)		560
		Men's Apparel Provider in China
				670,182
		> Travel 2.8%
	3,850,000	Gaylord Entertainment (a)(c)		115,500
		Convention Hotels
	3,900,000	Expedia		113,061
		Online Travel Services Company
	4,600,000	Avis Budget Group (a)		78,614
		Second Largest Car Rental Company
	1,250,000	Vail Resorts		57,775
		Ski Resort Operator & Developer
	1,289,880	HomeAway (a)		49,919
		Vacation Rental Online Marketplace
	3,000,000	Hertz (a)		47,640
		Largest U.S. Rental Car Operator
	2,000,000	Localiza Rent A Car (Brazil)		35,754
		Car Rental
	970,000	Choice Hotels		32,359
		Franchisor of Budget Hotel Brands
				530,622
		> Food & Beverage 1.7%
	1,900,000	Hansen Natural (a)		153,805
		Alternative Beverages
	1,170,000	Diamond Foods (b)(c)		89,318
		Snack Foods & Culinary Ingredients
	32,896,000	Olam International (Singapore)		73,128
		Agriculture Supply Chain Manager
	1,200,000	GLG Life Tech (Canada) (a)		8,064
		Produce an All-natural Sweetener Extracted from the Stevia Plant
	240,000	Lance		5,191
		Snack Foods
				329,506
		> Furniture & Textiles 0.9%
	4,000,000	Knoll (c)		80,280
		Office Furniture
	2,800,000	Herman Miller		76,216
		Office Furniture
	1,000,000	Interface		19,370
		Modular & Broadloom Carpet
				175,866

See accompanying notes to financial statements.

24

Number of Shares			Value (000)
		> Casinos & Gaming 0.9%
	1,590,000	Penn National Gaming (a)	$	64,141
		Regional Casino Operator
	3,400,000	Pinnacle Entertainment (a)(c)		50,660
		Regional Casino Operator
	3,000,000	Melco Crown Entertainment - ADR (Hong Kong) (a)		38,310
		Macau Casino Operator
	12,000,000	MGM China Holdings (Hong Kong) (a)		22,144
		Macau Casino Operator
				175,255
		> Educational Services 0.7%
	2,800,000	Career Education (a)		59,220
		Post-secondary Education
	1,700,000	Universal Technical Institute (c)		33,609
		Vocational Training
	350,000	ITT Educational Services (a)(b)		27,384
		Post-secondary Degree Services
	200,000	New Oriental Education & Technology - ADR (China) (a)		22,344
		Education Service Provider
	2,000,000	Voyager Learning, Contingent Value Rights (a)(d)		300
		Education Services for the K-12 Market
				142,857
		> Other Consumer Services 0.7%
	2,190,000	Lifetime Fitness (a)(c)		87,403
		Sport & Fitness Club Operator
	14,000,000	Lifestyle International (Hong Kong)		41,319
		Mid- to High-end Department Store Operator in Hong Kong & China
	4,250,000	Move (a)		9,307
		Real Estate Internet Websites
	1,325,000	IFM Investments (Century 21 China RE) - ADR (China) (a)		1,948
		Provides Real Estate Services in China
				139,977
		> Other Durable Goods 0.5%
	1,720,000	Jarden		59,357
		Branded Household Products
	415,000	Cavco Industries (a)(c)		18,675
		Manufactured Homes
	400,000	Tesla Motors (a)(b)		11,652
		Design, Manufacture & Sell High Performance Electric Vehicles
				89,684
		> Restaurants 0.4%
	2,000,000	AFC Enterprises (a)(c)		32,900
		Popeye's Restaurants
	480,000	P.F. Chang's China Bistro		19,315
		Mandarin Style Restaurants
	675,000	Bravo Brio Restaurant Group (a)		16,490
		Upscale Casual Italian Restaurants
	450,000	Cheesecake Factory (a)		14,117
		Casual Dining Restaurants
				82,822

Number of Shares			Value (000)
		> Consumer Goods Distribution 0.3%
	2,100,000	Pool	$	62,601
		Distributor of Swimming Pool Supplies & Equipment
				62,601
		> Leisure Products 0.3%
	1,980,000	Thor Industries		57,103
		RV & Bus Manufacturer
				57,103
		> Nondurables 0.3%
	1,600,000	Helen of Troy (a)(c)		55,248
		Hair Dryers & Curling Irons
				55,248
		> Other Entertainment 0.1%
	173,436	CTS Eventim (Germany)		11,984
		Event Ticket Sales
				11,984
Consumer Goods & Services: Total				3,531,039
Industrial Goods & Services 18.3%
		> Machinery 10.1%
	6,750,000	Ametek		303,075
		Aerospace/Industrial Instruments
	4,200,000	Donaldson (c)		254,856
		Industrial Air Filtration
	3,000,000	Nordson		164,550
		Dispensing Systems for Adhesives & Coatings
	3,535,000	Pentair		142,673
		Pumps & Water Treatment
	2,900,000	Kennametal		122,409
		Consumable Cutting Tools
	2,565,000	Clarcor (c)		121,273
		Mobile & Industrial Filters
	3,650,000	Oshkosh (a)		105,631
		Specialty Truck Manufacturer
	1,800,000	Pall		101,214
		Filtration & Fluids Clarification
	2,250,000	HEICO (c)		89,460
		FAA Approved Aircraft Replacement Parts
	2,050,000	MOOG (a)		89,216
		Motion Control Products for Aerospace, Defense & Industrial Markets
	2,200,000	ESCO Technologies (c)		80,960
		Automatic Electric Meter Readers
	1,150,000	WABCO Holdings (a)		79,419
		Truck & Bus Component Supplier
	805,000	Toro		48,703
		Turf Maintenance Equipment
	1,300,000	Mine Safety Appliances		48,542
		Safety Equipment
	1,300,000	Kaydon		48,516
		Specialized Friction & Motion Control Products
	600,000	Wabtec		39,432
		Freight & Transit Component Supplier
	1,600,000	Generac (a)		31,040
		Stand-by Power Generators
	287,000	Neopost (France)		24,655
		Postage Meter Machines

See accompanying notes to financial statements.

25

Columbia Acorn Fund

Statement of Investments (Unaudited), continued

Number of Shares			Value (000)
		> Machinery—continued
	3,500,000	Jain Irrigation Systems (India)	$	13,382
		Agricultural Micro-irrigation Systems & Food Processing
	10,000,000	Marel (Iceland) (a)		10,586
		Largest Manufacturer of Poultry & Fish Processing Equipment
	100,000	Valmont Industries		9,639
		Center Pivot Irrigation Systems & Utility Poles
	1,250,000	Spartan Motors		6,750
		Specialty Truck & Chassis Manufacturer
				1,935,981
		> Industrial Materials & Specialty Chemicals 2.4%
	1,650,000	Albemarle		114,180
		Refinery Catalysts & Other Specialty Chemicals
	650,000	FMC Corp.		55,913
		Niche Specialty Chemicals
	340,000	Novozymes (Denmark)		55,329
		Industrial Enzymes
	673,000	Sociedad Quimica y Minera de Chile - ADR (Chile)		43,557
		Producer of Specialty Fertilizers, Lithium & Iodine
	1,260,000	Drew Industries (c)		31,147
		RV & Manufactured Home Components
	524,000	Mersen (France)		29,559
		Advanced Industrial Materials
	1,100,000	Albany International		29,029
		Paper Machine Clothing & Advanced Textiles
	10,000	Sika (Switzerland)		24,109
		Chemicals for Construction & Industrial Applications
	831,000	Nalco		23,110
		Provider of Water Treatment & Process Chemicals & Services
	350,000	Greif		22,761
		Industrial Packaging
	2,218,700	Kansai Paint (Japan)		20,215
		Paint Producer in Japan, India, China & Southeast Asia
	400,000	Silgan Holdings		16,388
		Metal & Plastic Packaging
				465,297
		> Other Industrial Services 2.0%
	3,200,000	Expeditors International of Washington		163,808
		International Freight Forwarder
	1,767,165	Imtech (Netherlands)		62,503
		Electromechanical & Information & Communications Technologies Installation & Maintenance
	1,300,000	Forward Air		43,927
		Freight Transportation Between Airports
	1,600,000	Mobile Mini (a)		33,904
		Portable Storage Units Leasing
	900,000	LKQ (a)		23,481
		Alternative Auto Parts Distribution
	1,000,000	UTI Worldwide		19,690
		Freight Forwarding & Logistics

Number of Shares			Value (000)
	626,524	Arcadis (Netherlands)	$	15,327
		Engineering Consultants
	1,050,000	TrueBlue (a)		15,204
		Temporary Manual Labor
	10,000,000	Hutchison Port Holdings Trust (Hong Kong) (a)		8,450
		Southern China Container Ports
				386,294
		> Industrial Distribution 1.0%
	900,000	WW Grainger		138,285
		Industrial Distribution
	2,600,000	Interline Brands (a)(c)		47,762
		Industrial Distribution
	100,000	Watsco		6,799
		HVAC Distribution
				192,846
		> Electrical Components 0.6%
	1,440,000	Acuity Brands		80,323
		Commercial Lighting Fixtures
	1,500,000	Ushio (Japan)		29,659
		Industrial Light Sources
	351,000	Saft (France)		12,071
		Niche Battery Manufacturer
				122,053
		> Waste Management 0.6%
	1,672,500	Waste Connections		53,068
		Solid Waste Management
	1,000,000	Republic Services		30,850
		Solid Waste Management
	280,000	Clean Harbors (a)		28,910
		Hazardous Waste Services & Disposal
				112,828
		> Outsourcing Services 0.5%
	2,800,000	Quanta Services (a)		56,560
		Electrical & Telecom Construction Services
	1,210,000	Insperity		35,828
		Professional Employer Organization
	600,000	GP Strategies (a)		8,196
		Training Programs
				100,584
		> Construction 0.4%
	66,000	NVR (a)		47,882
		D.C. Homebuilder
	1,800,000	Mills Estruturas e Serviços de Engenharia (Brazil)		25,951
		Civil Engineering & Construction
	360,073	Simpson Manufacturing		10,755
		Wall Joint Maker
				84,588
		> Conglomerates 0.4%
	2,263,654	Aalberts Industries (Netherlands)		52,916
		Flow Control & Heat Treatment
	600,000	Ibiden (Japan)		18,785
		Electronic Parts & Ceramics
				71,701

See accompanying notes to financial statements.

26

Number of Shares			Value (000)
		> Steel 0.3%
	2,340,000	GrafTech International (a)	$	47,432
		Industrial Graphite Materials Producer
				47,432
		> Water —%
	649,641	Mueller Water Products		2,586
		Fire Hydrants, Valves & Ductile Iron Pipes
				2,586
Industrial Goods & Services: Total				3,522,190
Energy & Minerals 9.8%
		> Oil Services 3.9%
	6,200,000	FMC Technologies (a)		277,698
		Oil & Gas Wellhead Manufacturer
	2,641,054	Fugro (Netherlands)		190,424
		Sub-sea Oilfield Services
	2,399,000	Atwood Oceanics (a)		105,868
		Offshore Drilling Contractor
	743,000	Oil States International (a)		59,373
		Diversified North American Oil Service Provider
	1,670,000	ShawCor (Canada)		51,289
		Oil & Gas Pipeline Products
	375,000	Bristow		19,132
		Largest Provider of Helicopter Services to Offshore Oil & Gas Producers
	528,300	Black Diamond Group (Canada)		17,255
		Provides Accommodations/Equipment for Oil Sands Exploitation
	500,000	Hornbeck Offshore (a)		13,750
		Supply Vessel Operator in U.S. Gulf of Mexico
	2,890,900	Horizon North Logistics (Canada)		13,429
		Provides Diversified Oil Service Offering in Northern Canada
	9,519,200	Tuscany International Drilling (Colombia) (a)		9,080
	1,040,000	Tuscany International Drilling - Warrants (Colombia) (a)		38
		South America-based Drilling Rig Contractor
				757,336
		> Oil & Gas Producers 3.7%
	4,810,550	Pacific Rubiales Energy (Colombia)		128,936
		Oil Production & Exploration in Colombia
	1,650,000	Southwestern Energy (a)		70,752
		Oil & Gas Producer
	2,700,000	Denbury Resources (a)		54,000
		Oil Producer Using Co2 Injection
	715,000	SM Energy		52,538
		Oil & Gas Producer
	974,000	Rosetta Resources (a)		50,200
		Oil & Gas Producer Exploring in South Texas & Montana
	2,400,000	Tullow Oil (United Kingdom)		47,763
		Oil & Gas Producer
	910,000	Ultra Petroleum (a)		41,678
		Oil & Gas Producer

Number of Shares			Value (000)
	695,000	Range Resources	$	38,572
		Oil & Gas Producer
	650,000	Baytex (Canada) (b)		35,531
		Oil & Gas Producer in Canada
	1,200,000	Houston American Energy (b)		21,756
		Oil & Gas Exploration & Production in Colombia
	27,063,400	ShaMaran Petroleum (Iraq) (a)		21,326
		Oil Exploration in Kurdistan
	550,000	Swift Energy (a)		20,499
		Oil & Gas Exploration & Production Company
	850,000	Northern Oil & Gas (a)(b)		18,828
		Small E&P Company in North Dakota Bakken
	250,000	Cabot Oil & Gas		16,578
		Large Natural Gas Producer in Appalachia & Gulf Coast
	293,000	Carrizo Oil & Gas (a)		12,233
		Oil & Gas Producer
	37,500,000	Petromanas (Canada) (a)(c)(d)		11,050
	18,750,000	Petromanas - Warrants (Canada) (a)(c)(d)		476
		Exploring for Oil in Albania
	26,000,000	Petrodorado (Colombia) (a)(c)		8,222
	24,000,000	Petrodorado - Warrants (Colombia) (a)(c)(d)		2,436
		Oil & Gas Exploration & Production in Colombia, Peru & Paraguay
	42,580,500	Alange Energy (Colombia) (a)(b)		9,713
		Oil & Gas Exploration & Production in Colombia
	484,500	Crew Energy (Canada) (a)		7,535
		Canadian Oil & Gas Producer
	575,000	Venoco (a)		7,326
		Oil & Gas Producer in California & Texas
	6,300,000	Canacol Energy (Colombia) (a)(d)		6,786
		Oil Producer in South America
	228,200	Oasis Petroleum (a)		6,773
		Oil Producer in North Dakota
	1,198,100	Pan Orient (Canada) (a)		6,659
		Growth Oriented & Return Focused Asian Explorer
	30,275,000	Petroamerica (Colombia) (a)(c)		5,023
		Oil Exploration & Production in Colombia
	8,400,000	Canadian Overseas Petroleum (United Kingdom) (a)(d)		3,884
	4,200,000	Canadian Overseas Petroleum - Warrants (United Kingdom) (a)(d)		572
		Oil & Gas Exploration/Production in the North Sea
	41,100,000	Quetzal Energy (Colombia) (a)(c)(d)		3,273
	8,900,000	Quetzal Energy (Colombia) (a)(c)		738
		Explores for Oil & Gas in Latin America
	175,400	Celtic Exploration (Canada) (a)		3,879
		Canadian Oil & Gas Producer
	2,245,000	Primary Petroleum (Canada) (a)		1,117
		Targeting Oil Deposits in Western Montana
				716,652

See accompanying notes to financial statements.

27

Columbia Acorn Fund

Statement of Investments (Unaudited), continued

Number of Shares			Value (000)
		> Mining 1.6%
	641,000	Core Laboratories (Netherlands) (b)	$	71,497
		Oil & Gas Reservoir Consulting
	1,950,000	Silver Wheaton (Canada)		64,350
		Silver Mining Royalty Company
	15,000,000	Zhaojin Mining Industry (China)		30,945
		Gold Mining & Refining in China
	1,150,000	Ivanhoe Mines (Canada) (a)		29,059
		Copper Mine Project in Mongolia
	4,432,000	Northam Platinum (South Africa)		27,837
		Platinum Mining in South Africa
	900,000	Silver Standard Resources (a)		24,021
		Silver Mining
	2,800,000	Alexco Resource (a)		20,188
		Mining, Exploration & Environmental Services
	5,000,000	Orko Silver (Canada) (a)(b)		14,464
		Silver Exploration & Development
	3,816,400	Duluth Metals (Canada) (a)		9,418
		Copper & Nickel Miner
	5,215,500	Mongolian Mining (Hong Kong) (a)		6,449
		Coking Coal Mining in Mongolia
	236,400	Tahoe Resources (Canada) (a)(d)		4,368
		Silver Project in Guatemala
	800,000	Augusta Resource (a)		3,704
		U.S. Copper/Molybdenum Mine
	4,000,000	Wolverine Minerals (Canada) (a)(c)(d)		2,389
	2,000,000	Wolverine Minerals - Warrants (Canada) (a)(c)(d)		281
		Gold Miner
				308,970
		> Alternative Energy 0.3%
	3,000,000	GT Solar International (a)(b)		48,600
		Largest Manufacturer of Furnaces & Reactors to Produce & Cast Polysilicon
	500,000	STR Holdings (a)(b)		7,460
		Makes Encapsulant for Solar Power Modules/Provides Quality Assurance
	1,210,300	Synthesis Energy Systems (China) (a)(b)		2,263
		Owner/Operator of Gasification Plants
				58,323
		> Oil Refining, Marketing & Distribution 0.2%
	600,000	Vopak (Netherlands)		29,400
		World's Largest Operator of Petroleum & Chemical Storage Terminals
				29,400
		> Agricultural Commodities 0.1%
	6,818,182	Union Agriculture Group (Argentina) (a)(d)		15,000
		Farmland Operator in Uruguay
				15,000
Energy & Minerals: Total				1,885,681

Number of Shares			Value (000)
Finance 9.5%
		> Banks 3.9%
	2,800,000	BOK Financial	$	153,356
		Tulsa-based Southwest Bank
	6,304,320	Valley National Bancorp (b)		85,802
		New Jersey/New York Bank
	5,413,800	Associated Banc-Corp		75,252
		Midwest Bank
	2,337,313	Hancock Holding (b)		72,410
		Gulf Coast Bank
	1,160,000	SVB Financial Group (a)		69,264
		Bank to Venture Capitalists
	1,145,000	City National		62,116
		Bank & Asset Manager
	2,860,000	MB Financial (c)		55,026
		Chicago Bank
	3,613,000	TCF Financial		49,859
		Great Lakes Bank
	4,300,000	CVB Financial (b)		39,775
		Inland Empire Business Bank
	4,056,427	First Busey		21,458
		Illinois Bank
	1,121,188	Sandy Spring Bancorp		20,170
		Baltimore/D.C. Bank
	1,350,000	TriCo Bancshares (c)		19,710
		California Central Valley Bank
	772,632	Hudson Valley		14,920
		Metro New York City Bank
	706,559	Eagle Bancorp (a)		9,397
		Metro D.C. Bank
	3,764,300	Shinsei Bank (Japan)		3,765
		Commercial Bank
	246,505	Pacific Continental		2,256
		Pacific Northwest Bank
	583,872	Green Bankshares (a)(b)		1,530
		Tennessee Bank
				756,066
		> Insurance 2.2%
	2,820,000	Leucadia National		96,162
		Insurance Holding Company
	9,400,000	CNO Financial Group (a)		74,354
		Life, Long-term Care & Medical Supplement Insurance
	1,320,000	Hanover Insurance Group		49,777
		Personal & Commercial Lines Insurance
	1,200,000	HCC Insurance Holdings		37,800
		Specialty Insurance
	832,000	Willis Group (Ireland)		34,204
		Insurance Broker
	1,000,000	Delphi Financial Group		29,210
		Workers Compensation & Group Employee Benefit Products & Services
	1,225,000	Tower Group		29,180
		Commercial & Personal Lines Insurance
	1,420,000	Selective Insurance Group		23,103
		Commercial & Personal Lines Insurance
	900,000	Brown & Brown		23,094
		Insurance Broker
	1,600,000	Symetra Financial		21,488
		Life Insurance

See accompanying notes to financial statements.

28

Number of Shares			Value (000)
		> Insurance—continued
	300,000	Assured Guaranty	$	4,893
		Global Muni Bond Insurance
	33,746	Enstar Group (a)		3,526
		Insurance/Reinsurance & Related Services
				426,791
		> Finance Companies 1.6%
	1,505,202	World Acceptance (a)(c)		98,696
		Personal Loans
	2,350,000	McGrath Rentcorp (c)		65,988
		Temporary Space & IT Rentals
	2,300,000	Aaron's		64,998
		Rent to Own
	3,000,000	H&E Equipment Services (a)(c)		41,970
		Heavy Equipment Leasing
	1,123,400	CAI International (a)(c)		23,209
		International Container Leasing
	1,091,000	Marlin Business Services (a)(c)		13,801
		Small Equipment Leasing
	90,020	GATX		3,342
		Rail Car Lessor
	78,500	Textainer Group Holdings		2,413
		Top International Container Leasor
				314,417
		> Brokerage & Money Management 1.4%
	6,198,000	SEI Investments		139,517
		Mutual Fund Administration & Investment Management
	3,391,000	Eaton Vance		102,510
		Specialty Mutual Funds
	400,000	Financial Engines (a)		10,368
		Asset management for 401k plans
	629,493	Investment Technology Group (a)		8,825
		Electronic Trading
				261,220
		> Credit Cards 0.2%
	400,000	Alliance Data Systems (a)(b)		37,628
		Diversified Credit Card Provider
				37,628
		> Savings & Loans 0.2%
	1,024,069	ViewPoint Financial		14,132
		Texas Thrift
	1,010,000	Provident New York Bancorp		8,444
		New York State Thrift
	452,146	Kaiser Federal Financial Group		5,570
		Los Angeles Savings & Loan
	65,991	Berkshire Hills Bancorp		1,478
		Northeast Thrift
				29,624
Finance: Total				1,825,746
Health Care 8.6%
		> Biotechnology & Drug Delivery 3.2%
	4,315,000	BioMarin Pharmaceutical (a)		117,411
		Biotech Focused on Orphan Diseases
	4,181,000	Seattle Genetics (a)(b)		85,794
		Antibody-based Therapies for Cancer

Number of Shares			Value (000)
	2,226,000	InterMune (a)	$	79,802
		Drugs for Pulmonary Fibrosis & Hepatitis C
	1,450,000	Onyx Pharmaceuticals (a)		51,185
		Commercial-stage Biotech Focused on Cancer
	2,400,000	Auxilium Pharmaceuticals (a)(c)		47,040
		Biotech Focused on Niche Disease Areas
	780,000	United Therapeutics (a)		42,978
		Biotech Focused on Rare Diseases
	4,500,000	NPS Pharmaceuticals (a)(c)		42,525
		Orphan Drugs & Healthy Royalties
	4,500,000	Isis Pharmaceuticals (a)		41,220
		Biotech Pioneer in Anti-sense Drugs
	5,500,000	Micromet (a)(b)(c)		31,570
		Next-generation Antibody Technology
	4,549,900	Chelsea Therapeutics (a)(b)(c)		23,205
		Biotech Focused on Rare Diseases
	3,300,000	Nabi Biopharmaceuticals (a)(c)		17,754
		Biotech Focused on Vaccines
	1,740,000	Anthera Pharmaceuticals (a)(b)(c)		14,216
		Biotech Focused on Cardiovascular, Cancer & Immunology
	2,300,000	Idenix Pharmaceuticals (a)		11,500
		Developer of Drugs for Infectious Diseases
	3,500,000	Array Biopharma (a)(c)		7,840
		Drugs for Cancer & Inflammatory Diseases
	359,944	MicroDose Technologies (a)(d)		374
		Drug Inhaler Development
	94,715	Locus Pharmaceuticals (a)(d)(e)		—
		High Throughput Rational Drug Design
				614,414
		> Medical Equipment & Devices 2.8%
	4,200,000	Alexion Pharmaceuticals (a)(b)		197,526
		Biotech Focused on Orphan Diseases
	1,800,000	Sirona Dental Systems (a)		95,580
		Manufacturer of Dental Equipment
	1,000,000	Edwards Lifesciences (a)		87,180
		Heart Valves
	700,000	Gen-Probe (a)		48,405
		Molecular In-vitro Diagnostics
	500,000	Idexx Laboratories (a)		38,780
		Diagnostic Equipment & Services for Veterinarians
	550,000	Haemonetics (a)		35,403
		Blood & Plasma Collection Equipment
	570,000	Orthofix International (a)		24,208
		Bone Fixation & Stimulation Devices
	1,650,000	Pacific Biosciences of California (a)(b)		19,305
		Genome Sequencing
				546,387
		> Medical Supplies 1.3%
	3,200,000	Cepheid (a)(c)		110,848
		Molecular Diagnostics
	2,126,000	Patterson Companies		69,924
		Dental, Veterinarian & Medical Distributor
	650,000	Henry Schein (a)		46,534
		Largest Distributor of Healthcare Products
	325,200	Neogen (a)		14,702
		Food & Animal Safety Products

See accompanying notes to financial statements.

29

Columbia Acorn Fund

Statement of Investments (Unaudited), continued

Number of Shares			Value (000)
		> Medical Supplies—continued
	200,000	Owens & Minor	$	6,898
		Distribution of Medical Supplies
				248,906
		> Health Care Services 0.8%
	1,655,000	Community Health Systems (a)		42,500
		Non-urban Hospitals
	3,800,000	Health Management Associates (a)		40,964
		Non-urban Hospitals
	400,000	HMS Holdings (a)		30,748
		Cost Containment Services
	4,250,000	eResearch Technology (a)(c)		27,073
		Clinical Research Services
	700,000	Allscripts Healthcare Solutions (a)		13,594
		IT for Physician Offices & Hospitals
				154,879
		> Pharmaceuticals 0.3%
	4,000,000	Akorn (a)		28,000
		Develops, Manufactures & Sells Specialty Generic Drugs
	2,393,955	Adcock Ingram Holdings (South Africa)		21,034
		Manufacturer of Pharmaceuticals & Medical Supplies
	1,818,154	Alimera Sciences (a)(b)(c)		14,818
		Ophthalmogy-focused Pharmaceutical Company
				63,852
		> Hospital Management 0.2%
	1,450,000	Kindred Healthcare (a)		31,131
		Post-Acute Healthcare Facilities
				31,131
Health Care: Total				1,659,569
Other Industries 5.8%
		> Real Estate 3.5%
	4,575,000	BioMed Realty Trust		88,023
		Life Science-focused Office Buildings
	840,000	Federal Realty Investment Trust		71,551
		Shopping Centers
	2,200,000	Dupont Fabros Technology (b)		55,440
		Technology-focused Office Buildings
	720,000	Digital Realty Trust (b)		44,481
		Technology-focused Office Buildings
	1,120,000	Kilroy Realty		44,229
		West Coast Office & Industrial Properties
	2,700,000	Associated Estates Realty (c)		43,875
		Multi-family Properties
	975,000	Post Properties		39,741
		Multi-family Properties
	1,850,000	Extra Space Storage		39,460
		Self Storage Facilities
	43,000,000	Mapletree Logistics Trust (Singapore)		32,243
		Industrial Property Landlord
	530,000	Macerich		28,355
		Regional Shopping Malls
	900,000	Corporate Office Properties		27,999
		Office Buildings

Number of Shares			Value (000)
	3,000,000	Education Realty Trust	$	25,710
		Student Housing
	15,000,000	Ascendas REIT (Singapore)		24,949
		Industrial Property Landlord
	700,000	Washington REIT		22,764
		Washington D.C. Diversified Properties
	3,750,000	DCT Industrial Trust		19,612
		Industrial Properties
	1,481,994	Summit Hotel Properties (c)		16,821
		Owner of Select Service Hotels
	2,800	Orix JREIT (Japan)		15,473
		Diversified REIT
	3,050,000	Kite Realty Group		15,189
		Community Shopping Centers
	699,701	St. Joe (a)		14,582
		Florida Panhandle Landowner
	37,407	Security Capital European Realty (Luxembourg) (a)(d)(e)		—
		Self Storage Properties
				670,497
		> Transportation 1.3%
	1,730,000	JB Hunt Transport Services		81,465
		Truck & Intermodal Carrier
	2,800,000	Rush Enterprises, Class A (a)(c)		53,284
	550,000	Rush Enterprises, Class B (a)(c)		8,855
		Truck Sales & Services
	1,260,000	World Fuel Services		45,272
		Global Fuel Broker
	2,730,000	Heartland Express		45,209
		Regional Trucker
	400,000	Genesee & Wyoming (a)		23,456
		Short-line Operator
				257,541
		> Regulated Utilities 1.0%
	2,000,000	Northeast Utilities		70,340
		Regulated Electric Utility
	1,800,000	Wisconsin Energy		56,430
		Wisconsin Utility
	500,000	ALLETE		20,520
		Regulated Electric Utility in Minnesota
	333,000	Red Eléctrica de España (Spain)		20,101
		Spanish Power Transmission
	3,333,000	Terna (Italy) (b)		15,496
		Italian Power Transmission
				182,887
Other Industries: Total				1,110,925
Total Equities: 97.5% (Cost: $11,304,342)				18,778,101
Securities Lending Collateral – 1.8%
	352,904	Dreyfus Government Cash Management Fund (f) (7 day yield of 0.00%)		352,904
Total Securities Lending Collateral: (Cost: $352,904)				352,904

See accompanying notes to financial statements.

30

Principal Amount			Value (000)
Short-Term Obligation 2.8%
		> Repurchase Agreement 2.8%
$	534,686	Repurchase Agreement with Fixed Income Clearing Corp., dated 6/30/11, due 7/01/11 at 0.01%, collateralized by U.S. Government Agency obligations with various maturities to 12/03/15, market value $545,385 (repurchase proceeds $534,686)	$	534,686
				534,686
Total Short-Term Obligation: (Amortized Cost: $534,686)				534,686
Total Investments: 102.1% (Cost: $12,191,932)(g)(h)				19,665,691
Obligation to Return Collateral for Securities Loaned: (1.8)%				(352,904	)
Cash and Other Assets Less Liabilities: (0.3)%				(60,928	)
Total Net Assets: 100.0%			$	19,251,859

ADR = American Depositary Receipts

GDR = Global Depository Receipts

See accompanying notes to financial statements.

31

Columbia Acorn Fund

Statement of Investments (Unaudited), 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 June 30, 2011. The total market value of Fund securities on loan at June 30, 2011 was $340,090.

(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 six months ended June 30, 2011, are as follows:

Affiliates	Balance of Shares Held 12/31/10		Purchases/ Additions		Sales/ Reductions		Balance of Shares Held 6/30/11		Value		Dividend
AFC Enterprises		2,000,000		-		-		2,000,000	$	32,900	$	-
Allos Therapeutics*		7,035,000		-		7,035,000		-		-		-
Alimera Sciences		361,450		1,456,704		-		1,818,154		14,818		-
Anthera Pharmaceuticals		1,450,000		290,000		-		1,740,000		14,216		-
Array Biopharma		3,500,000		-		-		3,500,000		7,840		-
Art Technology Group*		9,000,000		-		9,000,000		-		-		-
Associated Estates Realty		2,200,000		500,000		-		2,700,000		43,875		748
Auxilium Pharmaceuticals		1,200,000		1,200,000		-		2,400,000		47,040		-
Bally Technologies		3,725,000		-		-		3,725,000		151,533		-
Blackbaud		2,250,000		-		-		2,250,000		62,370		540
CAI International		1,650,000		-		526,600		1,123,400		23,209		-
Cavco Industries		180,000		235,000		-		415,000		18,675		-
Cepheid		2,415,000		785,000		-		3,200,000		110,848		-
Chelsea Therapeutics		3,449,900		1,100,000		-		4,549,900		23,205		-
Clarcor		2,565,000		-		-		2,565,000		121,273		539
Cogent Communications		2,800,000		-		280,000		2,520,000		42,865		-
Constant Contact		1,400,000		550,000		-		1,950,000		49,491		-
Diamond Foods		1,300,000		-		130,000		1,170,000		89,318		117
Donaldson		4,200,000		-		-		4,200,000		254,856		1,176
Drew Industries		1,260,000		-		-		1,260,000		31,147		-
Education Realty Trust*		3,000,000		-		-		3,000,000		25,710		300
eResearch Technology		4,250,000		-		-		4,250,000		27,073		-
ESCO Technologies		2,200,000		-		-		2,200,000		80,960		352
Gaiam		1,371,366		-		-		1,371,366		6,816		-
Gaylord Entertainment		3,850,000		-		-		3,850,000		115,500		-
H&E Equipment Services		3,000,000		-		-		3,000,000		41,970		-
Hackett Group		4,500,000		-		-		4,500,000		22,905		-
HEICO		1,700,000		550,000		-		2,250,000		89,460		102
Helen of Troy		1,600,000		-		-		1,600,000		55,248		-
iGate		2,913,065		-		13,065		2,900,000		47,328		-
II-VI		2,225,000		2,325,000		-		4,550,000		116,480		-
Informatica*		5,200,000		-		500,000		4,700,000		274,621		-
Interline Brands		2,600,000		-		-		2,600,000		47,762		-
IPG Photonics		2,710,000		70,000		-		2,780,000		202,134		-
IXYS		1,900,000		-		-		1,900,000		28,462		-
Kenexa		2,025,000		-		-		2,025,000		48,560		-
Knoll		4,000,000		-		-		4,000,000		80,280		640
Lifetime Fitness		2,190,000		-		-		2,190,000		87,403		-
lululemon athletica		4,035,000		-		43,735		3,991,265		446,304		-
Marlin Business Services		1,091,000		-		-		1,091,000		13,801		-
MB Financial		2,860,000		-		-		2,860,000		55,026		57
McGrath Rentcorp		2,350,000		-		-		2,350,000		65,988		1,069
Micromet		5,500,000		-		-		5,500,000		31,570		-
Nabi Biopharmaceuticals		1,383,454		1,916,546		-		3,300,000		17,754		-
Nanosphere*		1,480,056		-		1,480,056		-		-		-
Navigant Consulting		3,100,000		-		-		3,100,000		32,519		-
NPS Pharmaceuticals		3,200,000		1,300,000		-		4,500,000		42,525		-
Orko Silver*		10,000,000		-		5,000,000		5,000,000		14,464		-
Orthofix International*		1,150,000		-		580,000		570,000		24,208		-
PAETEC Holding		9,600,000		-		-		9,600,000		45,984		-
Pericom Semiconductor		1,765,000		-		-		1,765,000		15,779		-
Petroamerica		30,275,000		-		-		30,275,000		5,023		-
Petrodorado		48,000,000		2,000,000		-		50,000,000		10,658		-
Petrolifera Petroleum*		13,950,000		-		13,950,000		-		-		-
Petromanas		56,250,000		-		-		56,250,000		11,526		-
Pinnacle Entertainment		3,400,000		-		-		3,400,000		50,660		-

See accompanying notes to financial statements.

32

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

Affiliates	Balance of Shares Held 12/31/10		Purchases/ Additions		Sales/ Reductions		Balance of Shares Held 6/30/11		Value		Dividend
Quetzal Energy		-		50,000,000		-		50,000,000	$	4,011	$	-
Rush Enterprises		3,350,000		-		-		3,350,000		62,139		-
Salem Communications		1,541,000		-		-		1,541,000		5,532		-
Shutterfly		1,700,000		600,000		-		2,300,000		132,066		-
Spanish Broadcasting System		2,400,000		-		-		2,400,000		1,680		-
SPS Commerce		856,429		43,571		-		900,000		16,011		-
Summit Hotel Properties		-		1,481,994		-		1,481,994		16,821		61
Supertex		1,035,000		-		100,000		935,000		20,944		-
Talbots*		4,150,000		-		3,321,500		828,500		2,767		-
THQ*		3,567,000		-		3,567,000		-		-		-
TriCo Bancshares		1,350,000		-		-		1,350,000		19,710		243
True Religion Apparel		2,047,000		-		-		2,047,000		59,527		-
Tuscany International Drilling*+		13,319,200		4,589,700		7,349,700		10,559,200		9,118		-
tw telecom		9,500,000		-		-		9,500,000		195,035		-
Tyler Technologies		2,000,000		-		-		2,000,000		53,560		-
Universal Technical Institute		1,700,000		-		-		1,700,000		33,609		-
Virtusa		2,000,000		125,000		-		2,125,000		40,269		-
Warnaco Group*		2,190,000		-		-		2,190,000		114,427		-
Wolverine Minderals		-		6,000,000		-		6,000,000		2,670		-
World Acceptance		1,505,202		-		-		1,505,202		98,696		-
Total of Affiliated Transactions		358,776,122		77,118,515		52,876,656		383,017,981	$	4,310,532	$	5,944

*   At June 30, 2011, the Fund owned less than five percent of the company's outstanding voting shares.

+   Includes the effects of a corporate action.

  The aggregate cost and value of these companies at June 30, 2011, were $2,325,878 and $3,845,216, respectively. Investments in affiliated companies represented 20.0% of the Fund's total net assets at June 30, 2011.

(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 June 30, 2011, the market value of these securities amounted to $66,613, which represented 0.35% of total net assets.

  Additional information on these securities is as follows:

Security	Acquisition Dates	Shares		Cost		Value
Mail.ru - GDR	11/5/10-12/31/10		464,305	$	16,518	$	15,424
Union Agriculture Group	12/08/10		6,818,182		15,000		15,000
Petromanas	5/20/10		37,500,000		13,032		11,050
Canacol Energy	4/15/10		6,300,000		4,667		6,786
Tahoe Resources	5/28/10		236,400		1,350		4,368
Canadian Overseas Petroleum	11/24/10		8,400,000		3,591		3,884
Quetzal Energy	1/14/11		41,100,000		5,193		3,273
Petrodorado - Warrants	11/20/09		24,000,000		2,965		2,436
Wolverine Minerals	6/03/11		4,000,000		2,005		2,389
Canadian Overseas Petroleum - Warrants	11/24/10		4,200,000		526		572
Petromanas - Warrants	5/20/10		18,750,000		1,086		476
MicroDose Technologies	11/24/00		359,944		2,005		374
Voyager Learning, Contingent Value Rights	12/24/09		2,000,000		-		300
Wolverine Minerals - Warrants	6/03/11		2,000,000		243		281
Locus Pharmaceuticals	9/05/01-2/08/07		94,715		7,780		-
Security Capital European Realty	8/20/98-7/20/99		37,407		205		-
				$	76,166	$	66,613

(e)  Security has no value.

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

(g)  At June 30, 2011, for federal income tax purposes, the cost of investments was $12,191,932 and net unrealized appreciation was $7,473,759, consisting of gross unrealized appreciation of $8,160,875 and gross unrealized depreciation of $687,116.

See accompanying notes to financial statements.

33

Columbia Acorn Fund

Statement of Investments (Unaudited), continued

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

(h)  On June 30, 2011, the market value of foreign securities represented 10.80% of total net assets. The Fund's foreign portfolio was diversified as follows:

	Value		Percent
Netherlands	$	422,067		2.19
Canada		326,015		1.69
Colombia		174,245		0.91
Singapore		161,045		0.84
Hong Kong		132,474		0.69
Sweden		127,222		0.66
Japan		125,073		0.65
France		66,285		0.34
China		62,305		0.32
Brazil		61,705		0.32
Denmark		55,329		0.29
United Kingdon		52,219		0.27
South Africa		48,871		0.25
	Value		Percent
Chile	$	43,557		0.23
Ireland		34,204		0.18
Israel		29,088		0.15
Switzerland		24,109		0.13
India		22,513		0.12
Iraq		21,326		0.11
Spain		20,101		0.10
Italy		15,496		0.08
Russia		15,424		0.08
Argentina		15,000		0.08
Germany		11,984		0.06
Iceland		10,586		0.06
Luxembourg		-		0.00
Total Foreign Portfolio	$	2,078,243		10.80

  Various inputs are used in determining the value of the Fund's investments, following the input prioritization hierarchy established by GAAP. These inputs are summarized in the three broad levels listed below:

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

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

•  Level 3 – prices determined using significant unobservable inputs where quoted prices or observable inputs are unavailable or less reliable (including management's own assumptions about the factors market participants would use in pricing an investment)

  The inputs or methodology 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 Fund 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 Valuation Committee of the Fund's Board of Trustees that rely on significant observable inputs are also included in Level 2. Typical Level 3 securities include any security fair valued by the Valuation Committee that relies on significant unobservable inputs.

The following table summarizes the inputs used, as of June 30, 2011, 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	$	5,032,026	$	210,925	$	-	$	5,242,951
Consumer Goods & Services		3,382,164		148,575		300		3,531,039
Industrial Goods & Services		3,153,094		369,096		-		3,522,190
Energy & Minerals		1,502,348		368,333		15,000		1,885,681
Finance		1,821,981		3,765		-		1,825,746
Health Care		1,638,161		21,034		374		1,659,569
Other Industries		1,002,663		108,262		-		1,110,925
Total Equities		17,532,437		1,229,990		15,674		18,778,101
Total Securities Lending Collateral		352,904		-		-		352,904
Total Short-Term Obligation		-		534,686		-		534,686
Total Investments	$	17,885,341	$	1,764,676	$	15,674	$	19,665,691

  The Fund's assets assigned to the Level 2 input category are generally valued using a market approach, in which a security's value is determined through its correlation to prices and information from observable market transactions for similar or identical assets. Foreign equities are generally valued at the last sales price on the foreign exchange or market on which they trade. The Fund may use a systematic fair valuation model provided by an independent third party to value securities principally traded in foreign markets in order to adjust for possible stale pricing that may occur between the close of the foreign exchanges and the time for valuation. These models take into account available market data including intraday index, ADR, and ETF movements. Securities acquired via private placement that have a holding period or an extended settlement period are valued at a discount to the same shares that are trading freely on the market. These discounts are determined by the adviser's experience with similar securities or situations. Factors may include, but are not limited to, trade volume, shares outstanding and stock price. Warrants which do not trade are valued as a percentage of the actively trading common stock using a model based on Black Scholes.

See accompanying notes to financial statements.

34

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

  Certain short-term obligations may be valued using amortized cost, an income approach which converts future cash flows to a present value based upon the discount or premium at purchase.

  The Fund's assets assigned to the Level 3 input category are valued at fair value as determined in good faith under consistently applied procedures established by and under the general supervision of the Board of Trustees. To determine fair value, management will utilize the valuation technique that they deem the most appropriate in the circumstances. Securities acquired via private placement but are not yet trading are valued using the market approach for which management has determined that the original transaction price is the best representation of fair value. The original cost may be adjusted for the market movement in an index, ETF or similar security during the period it does not trade. Securities for which no market exist are valued based upon the market approach using some unobservable inputs which may include, but are not limited to, projected earnings, available cash, line of business, multiples, and consideration of the prioritization of the equity in a company's capital structure.

  The following table reconciles asset balances for the six months ending June 30, 2011, in which significant unobservable inputs (Level 3) were used in determining value:

Investments in Securities	Balance as of December 31, 2010		Realized Gain/(Loss)		Change in Unrealized Appreciation (Depreciation)		Purchases		Sales		Transfers into Level 3		Transfers out of Level 3		Balance as of June 30, 2011
Equities
Consumer Goods & Services	$	262	$	-	$	38	$	-	$	-	$	-	$	-	$	300
Energy & Minerals		15,000		-		-		-		-		-		-		15,000
Health Care		103		-		271		-		-		-		-		374
	$	15,365	$	-	$	309	$	-	$	-	$	-	$	-	$	15,674

  The information in the above reconciliation table represents fiscal year to date activity for any securities identified as using Level 3 inputs at either the beginning or the end of the current fiscal period.

  The change in unrealized appreciation attributed to securities owned at June 30, 2011, which were valued using significant unobservable inputs (Level 3) amounted to $309. This amount is included in net change in unrealized appreciation (depreciation) on the Statements of Changes in Net Assets.

  The following table shows transfers between Level 1 and Level 2 of the fair value hierarchy:

Transfers In				Transfers Out
Level 1		Level 2		Level 1		Level 2
$	54,754	$	-	$	-	$	54,754

  Financial assets were transferred from Level 2 to Level 1 as they resumed trading during the period.

  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.

35

Columbia Acorn International

Major Portfolio Changes in the Second Quarter (Unaudited)

	Number of Shares
	03/31/11		06/30/11
Purchases
Europe
> United Kingdom
GlobeOp Financial Services		3,100,000		3,758,000
JLT Group		2,147,000		2,868,800
Kesa Electricals		0		8,346,000
Next		0		582,000
Smith & Nephew		1,445,775		1,630,000
> Netherlands
Fugro		763,202		784,111
Imtech		1,803,729		1,841,280
USG People		1,079,600		1,093,994
> France
Gemalto		639,000		799,000
Teleperformance		670,000		1,078,000
> Germany
Dürr		0		237,511
Rhoen-Klinikum		1,110,000		1,460,000
> Switzerland
Dufry Group		0		190,000
Partners Group		185,000		235,000
> Norway
Atea		340,964		2,045,964
> Belgium
EVS Broadcast Equipment		0		145,031
Asia
> Japan
Asics		3,008,500		3,650,000
Hoshizaki Electric		1,532,300		1,563,000
Ibiden		711,000		819,000
Japan Airport Terminal		1,250,000		1,666,700
Kuraray		1,670,000		1,974,000
Shinsei Bank		13,353,800		23,908,800
Sintokogio		1,172,500		1,794,000
Torishima Pump Manufacturing		972,500		1,250,500
Ushio		1,170,800		1,292,500
> Singapore
Mapletree Commercial Trust		0		30,000,000
> Hong Kong
MGM China Holdings		0		12,000,000
Sa Sa International		33,000,000		35,000,000
> China
ENN Energy		0		6,000,000
Noah Holdings - ADR		223,100		432,790
Want Want		0		7,143,600

	Number of Shares
	03/31/11		06/30/11
> Taiwan
China Steel Chemical		2,966,500		4,192,000
Far Eastone Telecom		4,957,300		21,429,000
President Chain Store		3,362,500		5,665,000
St. Shine Optical		1,133,100		1,511,000
Taiwan Hon Chuan		4,639,400		6,911,000
> India
Jain Irrigation Systems		7,675,000		8,587,418
Mundra Port & Special Economic Zone		6,360,300		7,496,953
United Breweries		0		367,138
> Thailand
Home Product Center		58,207,800		80,000,000
> Indonesia
Ace Indonesia		0		6,898,100
Other Countries
> Canada
Alliance Grain Traders		0		501,700
Celtic Exploration		0		146,200
Crew Energy		0		367,600
> United States
Oil States International		0		250,000
> South Africa
Coronation Fund Managers		1,788,501		8,723,060
Rand Merchant Insurance		10,355,359		17,625,208
Latin America
> Brazil
Multiplus		0		1,100,000
> Colombia
Canacol Energy		8,058,800		8,240,000

See accompanying notes to financial statements.

36

	Number of Shares
	03/31/11		06/30/11
Sales
Europe
> United Kingdom
Cobham		9,259,000		5,385,000
FlyBe		1,462,658		1,376,083
Serco		6,700,000		3,513,800
> France
Eurofins Scientific		600,800		489,287
Toreador Resources		372,000		0
> Germany
CTS Eventim		490,000		403,286
Vossloh		240,000		165,000
> Sweden
East Capital Explorer		916,662		905,452
Hexagon		4,382,000		3,799,000
> Italy
Tod's		452,200		257,200
> Ireland
United Drug		12,110,000		9,669,485
> Finland
Poyry		1,706,942		410,523
Asia
> Japan
Benesse		33,300		0
Gree		2,226,000		1,355,000
Start Today		2,421,300		1,275,000
Suruga Bank		1,750,000		0
> Singapore
Mapletree Logistics Trust		57,000,000		50,000,000
> China
China Communication Services		45,000,000		41,959,300
China Green		10,140,400		0
China Yurun Food		12,199,600		10,764,600
Jiangsu Expressway		36,700,000		23,146,000
New Oriental Education & Technology - ADR		278,315		230,000
Wasion Group		29,425,300		24,244,400
Zuoan Fashion		817,360		680,503
> Taiwan
Formosa International Hotels		1,599,620		1,142,620
Simplo Technology		7,200,000		5,821,000
> India
Asian Paints		368,098		320,000
Housing Development Finance		1,100,000		0
Infrastructure Development Finance		5,675,000		3,550,000
Shriram Transport Finance		1,835,000		715,000

	Number of Shares
	03/31/11		06/30/11
Other Countries
> Canada
Baytex		735,000		574,000
Guyana Goldfields		1,355,000		1,291,135
> United States
Atwood Oceanics		1,340,000		1,273,000
Tesco		324,000		0
> Australia
Hastie Group		3,962,289		0
SAI Global		7,286,896		6,281,896
Latin America
> Brazil
Localiza Rent A Car		4,700,000		4,300,000
PDG Realty		5,000,000		4,400,000

See accompanying notes to financial statements.

37

Columbia Acorn International

Statement of Investments (Unaudited), June 30, 2011

Number of Shares			Value (000)
			Equities: 95.6%
Europe 37.4%
		> United Kingdom 7.0%
	2,000,000	Intertek Group	$	63,331
		Testing, Inspection & Certification Services
	5,437,000	Chemring		55,847
		Defense Manufacturer of Countermeasures & Energetics
	2,868,800	JLT Group		31,355
		International Business Insurance Broker
	3,513,800	Serco		31,158
		Facilities Management
	56,093,000	Workspace Group		27,233
		United Kingdom Real Estate
	26,712,371	Archipelago Resources (a)		26,474
		Gold Mining Projects in Indonesia, Vietnam & the Philippines
	3,758,000	GlobeOp Financial Services		23,613
		Hedge Fund Administrator
	1,976,000	Petropavlovsk		23,151
		Gold & Iron Ore Mining in Russia
	582,000	Next		21,717
		Clothes & Home Retailer in the United Kingdom
	8,346,000	Kesa Electricals		18,445
		Europe's Leading Electricals Retailers
	2,752,210	Abcam		18,409
		Online Sales of Antibodies
	680,000	Rotork		18,400
		Valve Actuators for Oil & Water Pipelines
	5,385,000	Cobham		18,288
		Aerospace Components
	2,432,000	Premier Oil (a)		17,432
		Oil & Gas Producer in Europe, Pakistan & Asia
	1,630,000	Smith & Nephew		17,397
		Medical Equipment & Supplies
	690,000	Tullow Oil		13,732
		Oil & Gas Producer
	859,200	Shaftesbury		7,281
		London Prime Retail REIT
	3,889,000	PureCircle (a)(b)		5,524
		Natural Sweeteners
	1,650,000	SKIL Ports & Logistics (a)		5,164
		Indian Container Port Project
	1,549,500	Sterling Resources (a)		2,651
	1,050,500	Sterling Resources (a)(c)		1,761
		Oil & Gas Exploration - Europe
	1,376,083	FlyBe (a)		4,064
		Largest European Regional Airline
				452,427
		> Netherlands 6.4%
	1,841,280	Imtech		65,125
		Electromechanical & Information & Communications Technologies Installation & Maintenance
	784,111	Fugro		56,536
		Sub-sea Oilfield Services

Number of Shares			Value (000)
	1,104,200	Vopak	$	54,106
		World's Largest Operator of Petroleum & Chemical Storage Terminals
	2,296,992	Aalberts Industries		53,695
		Flow Control & Heat Treatment
	1,476,800	Unit 4 Agresso (d)		53,390
		Business Software Development
	1,272,365	Koninklijke TenCate		51,516
		Advanced Textiles & Industrial Fabrics
	1,164,669	Arcadis		28,493
		Engineering Consultants
	249,000	Core Laboratories		27,773
		Oil & Gas Reservoir Consulting
	1,093,994	USG People		18,918
		Temporary Staffing Services
				409,552
		> France 5.1%
	610,000	Neopost		52,403
		Postage Meter Machines
	489,287	Eurofins Scientific		45,070
		Food, Pharmaceuticals & Materials Screening & Testing
	799,000	Gemalto		38,207
		Smart Card Products & Solutions
	274,100	Rubis		34,772
		Tank Storage & Liquefied Petroleum Gas Distribution
	1,078,000	Teleperformance		31,680
		Call Center Operator
	902,900	Saft		31,051
		Niche Battery Manufacturer
	541,500	Mersen		30,546
		Advanced Industrial Materials
	322,200	Pierre & Vacances		26,862
		Vacation Apartment Lets
	213,800	Norbert Dentressangle		25,265
		Leading European Logistics & Transport Group
	1,689,100	Hi-Media (a)		10,116
		Online Advertiser in Europe
				325,972
		> Germany 3.9%
	630,000	Rheinmetall		55,775
		Defense & Automotive
	2,120,000	Wirecard (b)		37,891
		Online Payment Processing & Risk Management
	137,500	Rational		36,240
		Commercial Ovens
	1,460,000	Rhoen-Klinikum		35,230
		Health Care Services
	403,286	CTS Eventim		27,867
		Event Ticket Sales
	165,000	Vossloh		23,157
		Rail Infrastructure & Diesel Locomotives
	515,000	Elringklinger		18,275
		Automobile Components

See accompanying notes to financial statements.

38

Number of Shares			Value (000)
		> Germany—continued
	237,511	Dürr	$	9,644
		Automotive Plant Engineering & Associated Capital Equipment
	312,500	Deutsche Beteiligungs		8,814
		Private Equity Investment Management
				252,893
		> Switzerland 3.7%
	22,300	Sika		53,764
		Chemicals for Construction & Industrial Applications
	325,000	Kuehne & Nagel		49,325
		Freight Forwarding/Logistics
	185,000	Geberit (a)		43,832
		Plumbing Supplies
	235,000	Partners Group		41,592
		Private Markets Asset Management
	720,000	Bank Sarasin & Cie		28,517
		Private Banking
	190,000	Dufry Group (a)		23,932
		Operates Airport Duty Free & Duty Paid Shops
				240,962
		> Sweden 2.6%
	3,799,000	Hexagon (b)		93,576
		Measurement Equipment & Software
	3,887,000	Sweco		38,254
		Engineering Consultants
	607,000	Unibet (a)		13,171
		European Online Gaming Operator
	905,452	East Capital Explorer		10,521
		Sweden-based RUS/CEE Investment Fund
	708,342	Orc Software (b)		9,435
		Software for Securities Trading, Analysis & Risk Management
				164,957
		> Italy 2.4%
	257,200	Tod's		34,407
		Leather Shoes & Bags
	2,083,000	Ansaldo STS		29,195
		Railway Systems Integrator
	4,311,600	Credito Emiliano		27,273
		Italian Regional Bank
	9,796,000	CIR		24,533
		Italian Holding Company
	3,573,000	Geox		21,410
		Apparel & Shoe Maker
	4,111,000	Terna (b)		19,113
		Italian Power Transmission
				155,931
		> Denmark 1.2%
	306,000	Novozymes		49,796
		Industrial Enzymes
	156,000	SimCorp		30,785
		Software for Investment Managers
				80,581

Number of Shares			Value (000)
		> Ireland 1.1%
	9,669,485	United Drug	$	33,121
		Irish Pharmaceutical Wholesaler & Outsourcer
	359,000	Paddy Power		19,517
		Irish Betting Services
	297,000	Aryzta		15,735
		Baked Goods
				68,373
		> Portugal 0.6%
	7,278,105	Redes Energéticas Nacionais		26,164
		Portuguese Power Transmission & Gas Transportation
	22,568,987	Banco Comercial Português (a)		13,419
		Largest Portuguese Banking Franchise
				39,583
		> Iceland 0.6%
	35,982,499	Marel (a)		38,090
		Largest Manufacturer of Poultry & Fish Processing Equipment
				38,090
		> Spain 0.5%
	579,000	Red Eléctrica de España		34,950
		Spanish Power Transmission
				34,950
		> Finland 0.5%
	967,777	Stockmann (b)		27,423
		Department Store & Fashion Retailer in Scandinavia & Russia
	410,523	Poyry		5,876
		Engineering Consultants
				33,299
		> Czech Republic 0.5%
	121,268	Komercni Banka (b)		29,574
		Leading Czech Republic Universal Bank
				29,574
		> Russia 0.4%
	764,506	Mail.ru - GDR (a)(c)		25,397
		Internet Social Networking & Games for Russian Speakers
				25,397
		> Norway 0.3%
	2,045,964	Atea		21,521
		Leading Nordic IT Hardware/Software Re-seller & Installation Company
				21,521
		> Greece 0.2%
	6,475,300	Intralot		13,803
		Lottery & Gaming Systems & Services
				13,803
		> Poland 0.2%
	893,900	Central European Distribution (a)		10,012
		Largest Spirits Company in Central & Eastern Europe
				10,012

See accompanying notes to financial statements.

39

Columbia Acorn International

Statement of Investments (Unaudited), continued

Number of Shares			Value (000)
		> Belgium 0.2%
	145,031	EVS Broadcast Equipment	$	9,818
		Digital Live Mobile Production Software & Systems
				9,818
Europe: Total				2,407,695
Asia 36.8%
		> Japan 16.2%
	7,568,400	Kansai Paint		68,957
		Paint Producer in Japan, India, China & Southeast Asia
	3,650,000	Asics		54,481
		Footwear & Apparel
	21,000	Seven Bank		41,964
		ATM Processing Services
	1,846,000	Aeon Delight		37,221
		Facility Maintenance & Management
	6,400	Orix JREIT		35,367
		Diversified REIT
	1,563,000	Hoshizaki Electric		34,695
		Commercial Kitchen Equipment
	15,300	Advance Residence Investment		32,022
		Residential REIT
	710,000	Hamamatsu Photonics		30,698
		Optical Sensors for Medical & Industrial Applications
	3,283,000	Kamigumi		30,682
		Port Cargo Handling & Logistics
	1,360,000	Asahi Diamond Industrial		29,733
		Consumable Diamond Tools
	1,355,000	Gree (a)		29,621
		Mobile Social Networking Game Developer/Platform
	707,000	Ain Pharmaciez		29,090
		Dispensing Pharmacy/Drugstore Operator
	1,974,000	Kuraray		28,919
		Special Resin, Fine Chemical, Fibers & Textures
	868,000	Kintetsu World Express		28,505
		Airfreight Logistics
	274,000	Nakanishi		28,232
		Dental Tools & Machinery
	23,500	Wacom (d)		27,443
		Computer Graphic Illustration Devices
	24,022	Jupiter Telecommunications		26,875
		Largest Cable Service Provider in Japan
	819,000	Ibiden		25,641
		Electronic Parts & Ceramics
	1,292,500	Ushio		25,556
		Industrial Light Sources
	1,275,000	Start Today		25,461
		Online Japanese Apparel Retailer
	789,000	Tsumura		25,223
		Traditional Chinese/Japanese Herbal Rx Drugs (Kampo)
	23,908,800	Shinsei Bank		23,915
		Commercial Bank
	1,181,200	Daiseki		23,914
		Waste Disposal & Recycling

Number of Shares			Value (000)
	509,000	Makita	$	23,719
		Power Tools
	5,100	Osaka Securities Exchange		22,766
		Osaka Securities Exchange
	7,174,000	Nippon Sheet Glass		22,306
		Sheet Glass for Building & Automotive Use
	977,000	Glory		22,006
		Currency Handling Systems & Related Equipment
	2,400,000	Shimadzu		21,982
		Analytical Instruments, Medical & Industrial Equipment
	906,000	Aeon Mall		21,948
		Suburban Shopping Mall Developer, Owner & Operator
	2,850	Fukuoka		21,457
		Diversified REIT in Fukuoka
	2,870	Kakaku.com		20,181
		Online Price Comparison Services for Consumers
	1,250,500	Torishima Pump Manufacturing		20,072
		Industrial Pump for Power Generation & Water Supply Systems
	1,666,700	Japan Airport Terminal		19,411
		Airport Terminal Operator at Haneda
	1,794,000	Sintokogio		18,418
		Automated Casting Machines, Surface Treatment Systems & Consumables
	675,780	Icom		17,390
		Two Way Radio Communication Equipment
	587,800	Miura		17,039
		Industrial Boiler Maker, Seller, Distributor & Manufacturer
	4,458	Mori Hills		16,313
		Tokyo Centric Diversified REIT
	439,800	Pigeon		14,456
		Baby Care Products
				1,043,679
		> Singapore 4.6%
	35,981,000	Olam International		79,986
		Agriculture Supply Chain Manager
	23,000,000	CDL Hospitality Trust		38,607
		Hotel Owner/Operator
	50,000,000	Mapletree Logistics Trust		37,491
		Industrial Property Landlord
	22,000,000	Ascendas REIT		36,592
		Industrial Property Landlord
	37,010,000	Mapletree Industrial Trust		35,291
		Industrial Property Landlord
	4,000,000	Singapore Exchange		24,580
		Singapore Equity & Derivatives Market Operator
	30,000,000	Mapletree Commercial Trust (a)		21,127
		Retail & Office Property Landlord
	13,000,000	Goodpack		19,391
		International Bulk Container Leasing
				293,065
		> Hong Kong 4.3%
	7,000,000	Melco Crown Entertainment - ADR (a)(b)		89,390
		Macau Casino Operator

See accompanying notes to financial statements.

40

Number of Shares			Value (000)
		> Hong Kong—continued
	18,000,000	Lifestyle International	$	53,125
		Mid- to High-end Department Store Operator in Hong Kong & China
	23,335,500	Mongolian Mining (a)		28,855
		Coking Coal Mining in Mongolia
	30,000,000	Hutchison Port Holdings Trust (a)		25,350
		Southern China Container Ports
	35,000,000	Sa Sa International		22,487
		Cosmetics Retailer
	12,000,000	MGM China Holdings (a)		22,144
		Macau Casino Operator
	8,077,000	L'Occitane International (a)		21,636
		Skin Care & Cosmetics Producer
	750,000	Hong Kong Exchanges and Clearing		15,802
		Hong Kong Equity & Derivatives Market Operator
				278,789
		> China 4.2%
	32,276,000	Zhaojin Mining Industry		66,584
		Gold Mining & Refining in China
	10,764,600	China Yurun Food		30,437
		Meat Processor in China
	230,000	New Oriental Education & Technology - ADR (a)		25,696
		Education Service Provider
	41,959,300	China Communication Services		24,845
		China's Telecom Infrastructure Service Provider
	240,000,000	RexLot Holdings		23,216
		Lottery Equipment Supplier in China
	23,146,000	Jiangsu Expressway		21,218
		Chinese Toll Road Operator
	6,000,000	ENN Energy		20,460
		China's Largest Private Gas Operator
	11,286,200	Shandong Weigao		16,385
		Vertically Integrated Hospital Consumable Manufacturing
	247,000	51job - ADR (a)		13,864
		An Integrated Human Resources Service Provider
	24,244,400	Wasion Group		11,413
		Electronic Power Meter Total Solution Provider
	7,143,600	Want Want		6,936
		Chinese Branded Consumer Food Company
	432,790	Noah Holdings - ADR (a)(b)		4,865
		Wealth Management Product Distributor in China
	680,503	Zuoan Fashion (a)(b)		3,804
		Men's Apparel Provider in China
				269,723
		> Taiwan 3.5%
	5,821,000	Simplo Technology		47,049
		World's Largest Notebook Battery Pack Supplier
	21,429,000	Far Eastone Telecom		34,202
		Taiwan's Third Largest Mobile Operator
	5,665,000	President Chain Store		32,821
		Taiwan's Number One Convenience Chain Store Operator

Number of Shares			Value (000)
	1,511,000	St. Shine Optical	$	22,957
		World's Leading Disposable Contact Lens OEM
	4,192,000	China Steel Chemical		22,456
		Sole Coal Chemical Producer in Taiwan
	1,142,620	Formosa International Hotels		21,674
		Hotel, Food & Beverage Operation & Hospitality Management Services
	6,911,000	Taiwan Hon Chuan		20,837
		Beverage Packaging (Bottles, Caps & Labels) Manufacturer
	7,206,000	Everlight Electronics		19,409
		LED Packager
	2,211,000	Sinyi Realty		4,270
		Taiwanese Realty Company
				225,675
		> India 2.4%
	8,587,418	Jain Irrigation Systems		32,834
		Agricultural Micro-irrigation Systems & Food Processing
	7,496,953	Mundra Port & Special Economic Zone		27,203
		Indian West Coast Shipping Port
	320,000	Asian Paints		22,666
		India's Largest Paint Company
	30,574,905	REI Agro		17,444
		Basmati Rice Processing
	11,814,746	Manappuram General Finance		14,896
		Short-term Lending Collateralized by Household Gold
	9,600,000	S. Kumars Nationwide (a)		11,654
		Textiles, Clothing & Retail
	3,550,000	Infrastructure Development Finance (a)		10,427
		Infrastructure Finance in India
	715,000	Shriram Transport Finance		9,892
		Used Truck Finance
	367,138	United Breweries		4,374
		India's Largest Brewer
				151,390
		> South Korea 1.3%
	1,157,000	Woongjin Coway		41,264
		South Korean Household Appliance Rental Service Provider
	150,000	NHN (a)		26,593
		South Korea's Largest Online Search Engine
	121,132	MegaStudy		16,295
		Education Service Provider
				84,152
		> Thailand 0.3%
	80,000,000	Home Product Center		21,351
		Home Improvement Retailer
				21,351
		> Indonesia —%
	6,898,100	Ace Indonesia		2,433
		Home Improvement Retailer
				2,433
Asia: Total				2,370,257

See accompanying notes to financial statements.

41

Columbia Acorn International

Statement of Investments (Unaudited), continued

Number of Shares			Value (000)
Other Countries 15.8%
		> Canada 5.3%
	1,710,000	ShawCor	$	52,517
		Oil & Gas Pipeline Products
	977,500	Ivanhoe Mines (a)		24,700
	855,600	Ivanhoe Mines (a)(e)		21,647
		Copper Mine Project in Mongolia
	1,301,612	CCL Industries		44,752
		Leading Global Label Manufacturer
	574,000	Baytex (b)		31,377
		Oil & Gas Producer in Canada
	540,000	AG Growth		25,644
		Leading Manufacturer of Augers & Grain Handling Equipment
	605,000	Onex Capital		23,442
		Private Equity Firm
	546,500	Black Diamond Group		17,849
		Provides Accommodations/Equipment for Oil Sands Exploitation
	872,700	Tahoe Resources (a)(c)		16,125
		Silver Project in Guatemala
	2,696,000	DeeThree Exploration (a)(c)(d)		9,862
	1,042,877	DeeThree Exploration (a)(d)		3,893
		Canadian Oil & Gas Producer
	501,700	Alliance Grain Traders		13,421
		Global Leader in Pulse Processing & Distribution
	2,214,100	Horizon North Logistics		10,285
		Provides Diversified Oil Service Offering in Northern Canada
	5,737,500	Southern Arc Minerals (a)(c)(d)		10,086
		Gold & Copper Exploration in Indonesia
	1,291,135	Guyana Goldfields (a)		9,170
		Gold Mining Projects in Guyana
	1,480,610	Pan Orient (a)		8,229
		Growth Oriented & Return Focused Asian Explorer
	367,600	Crew Energy (a)		5,717
		Canadian Oil & Gas Producer
	12,500,000	Eacom Timber (a)(c)		3,937
		Canadian Lumber Producer
	12,500,000	Petromanas (a)(c)		3,683
	6,250,000	Petromanas - Warrants (a)(c)		159
		Exploring for Oil in Albania
	146,200	Celtic Exploration (a)		3,233
		Canadian Oil & Gas Producer
				339,728
		> United States 3.8%
	1,273,000	Atwood Oceanics (a)		56,177
		Offshore Drilling Contractor
	822,000	Alexion Pharmaceuticals (a)		38,659
		Biotech Focused on Orphan Diseases
	918,000	World Fuel Services		32,984
		Global Fuel Broker
	1,145,000	BioMarin Pharmaceutical (a)		31,155
		Biotech Focused on Orphan Diseases
	658,000	FMC Technologies (a)		29,472
		Oil & Gas Wellhead Manufacturer

Number of Shares			Value (000)
	250,000	Oil States International (a)	$	19,978
		Diversified North American Oil Service Provider
	391,000	Bristow		19,949
		Largest Provider of Helicopter Services to Offshore Oil & Gas Producers
	568,000	Textainer Group Holdings		17,460
		Top International Container Leasor
				245,834
		> South Africa 3.8%
	1,096,000	Naspers		61,909
		Media in Africa, China, Russia & Other Emerging Markets
	4,600,000	Mr. Price		46,396
		South African Retailer of Apparel, Household & Sporting Goods
	4,625,000	Adcock Ingram Holdings		40,636
		Manufacturer of Pharmaceuticals & Medical Supplies
	5,780,900	Northam Platinum		36,309
		Platinum Mining in South Africa
	17,625,208	Rand Merchant Insurance		32,191
		Directly Sold Property & Casualty Insurance; Holdings in Other Insurers
	8,723,060	Coronation Fund Managers		24,898
		South African Fund Manager
				242,339
		> Australia 1.7%
	2,482,000	UGL		37,092
		Engineering & Facilities Management
	467,000	Cochlear		36,145
		Cochlear Implants
	6,281,896	SAI Global		32,009
		Publishing, Certification & Compliance Services
	1,000,000	Seek		6,936
		Online Job Listing & Education
				112,182
		> Israel 0.7%
	2,890,000	Israel Chemicals		46,119
		Producer of Potash, Phosphates, Bromine & Specialty Chemicals
				46,119
		> Kazakhstan 0.3%
	1,770,000	Halyk Savings Bank of Kazakhstan - GDR (a)		15,841
		Largest Retail Bank & Insurer in Kazakhstan
				15,841
		> Senegal 0.2%
	43,000	Sonatel (f)		13,784
		Leading Telecoms Operator in Western Africa
				13,784
		> Egypt —%
	235,342	Paints & Chemical Industries (Pachin)		1,509
		Paints & Inks in Egypt
				1,509
Other Countries: Total				1,017,336

See accompanying notes to financial statements.

42

Number of Shares			Value (000)
Latin America 5.6%
		> Brazil 4.2%
	4,300,000	Localiza Rent A Car	$	76,872
		Car Rental
	3,000,000	Mills Estruturas e Serviços de Engenharia		43,251
		Civil Engineering & Construction
	5,937,000	Suzano		42,949
		Brazilian Pulp & Paper Producer
	1,300,000	Natura		32,487
		Direct Retailer of Cosmetics
	3,400,000	MRV Engenharia		28,234
		Brazilian Property Developer
	4,400,000	PDG Realty		24,782
		Brazilian Property Developer
	1,100,000	Multiplus		19,172
		Loyalty Program Operator in Brazil
				267,747
		> Mexico 0.5%
	580,000	Grupo Aeroportuario del Sureste - ADR		34,185
		Mexican Airport Operator
				34,185
		> Chile 0.4%
	340,000	Sociedad Quimica y Minera de Chile - ADR (b)		22,005
		Producer of Specialty Fertilizers, Lithium & Iodine
				22,005
		> Argentina 0.3%
	6,818,182	Union Agriculture Group (a)(c)		15,000
		Farmland Operator in Uruguay
	5,400,000	Madalena Ventures (a)(c)		3,128
		Oil & Gas Exploration in Argentina
				18,128
		> Colombia 0.2%
	8,240,000	Canacol Energy (a)		9,056
		Oil Producer in South America
	20,718,000	Gulf United (a)(c)		6,091
		Prospecting for Oil Alongside Large Producers in Colombia
				15,147
Latin America: Total				357,212
Total Equities: 95.6% (Cost: $4,331,138)				6,152,500
		Securities Lending Collateral: 1.4%
	90,620,846	Dreyfus Government Cash Management Fund (g) (7 day yield of 0.00%)		90,621
Total Securities Lending Collateral: (Cost: $90,621)				90,621

Principal Amount (000)			Value (000)
Short-Term Obligation 3.5%
		> Repurchase Agreement 3.5%
$	226,923	Repurchase Agreement with Fixed Income Clearing Corp., dated 6/30/11, due 7/01/11 at 0.01%, collateralized by U.S. Government Agency obligations with various maturities to 9/08/17, market value $231,463 (repurchase proceeds $226,923)	$	226,923
				226,923
Total Short-Term Obligation: (Cost: $226,923)				226,923
Total Investments: 100.5% (Cost: $4,648,682)(h)(i)				6,470,044
Obligation to Return Collateral for Securities Loaned: (1.4)%				(90,621	)
Cash and Other Assets Less Liabilities: 0.9%				60,237
Total Net Assets: 100.0%			$	6,439,660

ADR = American Depositary Receipts

GDR = Global Depositary Receipts

See accompanying notes to financial statements.

43

Columbia Acorn International

Statement of Investments (Unaudited), continued

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

(a)  Non-income producing security.

(b)  All or a portion of this security was on loan at June 30, 2011. The total market value of Fund securities on loan at June 30, 2011 was $88,468.

(c)  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 June 30, 2011, the market value of these securities amounted to $95,229, which represented 1.48% of total net assets.

  Additional information on these securities is as follows:

Security	Acquisition Dates	Shares		Cost		Value
Mail.ru - GDR	11/05/10-12/31/10		764,506	$	26,088	$	25,397
Tahoe Resources	5/28/10		872,700		4,984		16,125
Union Agriculture Group	12/08/10		6,818,182		15,000		15,000
Southern Arc Minerals	2/16/11		5,737,500		9,308		10,086
DeeThree Exploration	9/07/10-3/08/11		2,696,000		9,486		9,862
Gulf United	2/11/11		20,718,000		6,215		6,091
Eacom Timber	3/17/10		12,500,000		6,188		3,937
Petromanas	5/20/10		12,500,000		4,344		3,683
Madalena Ventures	10/21/10		5,400,000		3,422		3,128
Sterling Resources	12/02/10		1,050,500		3,135		1,761
Petromanas - Warrants	5/20/10		6,250,000		362		159
				$	88,532	$	95,229

(d)  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 six months ended June 30, 2011, are as follows:

Affiliates	Balance of Shares Held 12/31/10		Purchases/ Additions		Sales/ Reductions		Balance of Shares Held 6/30/11		Value		Dividend
DeeThree Exploration		2,392,877		1,346,000		-		3,738,877	$	13,755	$	-
Gulf United*		-		20,718,000		-		20,718,000		6,091		-
Southern Arc Minerals		-		5,737,500		-		5,737,500		10,086		-
Unit 4 Aggresso		1,476,800		-		-		1,476,800		53,390		450
United Drug*		12,110,000		-		2,440,515		9,669,485		33,121		1,013
Wacom		20,900		2,600		-		23,500		27,443		721
Workspace Group*		60,304,000		-		4,211,000		56,093,000		27,233		213
Total of Affiliated Transactions		76,304,577		27,804,100		6,651,515		97,457,162	$	171,119	$	2,397

*  At June 30, 2011, the Fund owned less than five percent of the company's outstanding voting shares.

  The aggregate cost and value of these affiliated companies at June 30, 2011, was $85,252 and $104,674, respectively. Investments in affiliated companies represented 1.6% of total net assets at June 30, 2011.

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

(f)  Illiquid security.

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

(h)  At June 30, 2011, for federal income tax purposes, the cost of investments was $4,648,682 and net unrealized apppreciation was $1,821,362, consisting of gross unrealized appreciation of $2,050,001 and gross unrealized depreciation of $228,639.

(i)  On June 30, 2011, the Fund's total investments were denominated in currencies as follows:

Currency	Value		Percentage of Net Assets
Euro	$	1,316,400		20.4
Japanese Yen		1,043,679		16.2
U.S. Dollar		904,297		14.0
British Pound		448,015		7.0
Hong Kong Dollar		385,544		6.0
Canadian Dollar		334,678		5.2
Other currencies less than 5% of total net assets		2,037,431		31.7
	$	6,470,044		100.5

See accompanying notes to financial statements.

44

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

  At June 30, 2011, the Fund had entered into the following forward foreign currency exchange contracts:

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 Appreciation
AUD		USD		40,296	$	42,000	7/15/11	$	1,165
AUD		USD		1,408		1,500	7/15/11		8
AUD		USD		38,544		40,500	8/15/11		627
AUD		USD		1,414		1,500	8/15/11		8
AUD		USD		39,736		42,000	9/15/11		234
CAD		USD		1,937		2,000	7/15/11		8
CAD		USD		3,876		4,000	7/15/11		18
CAD		USD		45,558		47,000	8/15/11		188
CAD		USD		3,879		4,000	8/15/11		18
CAD		USD		49,493		51,000	9/15/11		226
EUR		USD		3,877		5,500	7/15/11		120
JPY		USD		999,744		12,000	7/15/11		419
JPY		USD		484,386		6,000	8/15/11		18
					$	259,000		$	3,057
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
USD	AUD			1,422	$	1,500	7/15/11	$	(23	)
CAD	USD			43,344		45,000	7/15/11		(70	)
USD	EUR			68,493		99,000	7/15/11		(297	)
USD	EUR			4,150		6,000	7/15/11		(16	)
USD	EUR			65,972		93,500	8/15/11		(2,060	)
USD	EUR			4,154		6,000	8/15/11		(17	)
USD	EUR			68,953		99,500	9/15/11		(290	)
USD	JPY			484,482		6,000	7/15/11		(18	)
JPY	USD			40,220		500	7/15/11		-	*
JPY	USD			40,214		500	8/15/11		-	*
JPY	USD			522,691		6,500	9/15/11		(5	)
					$	364,000		$	(2,796	)

*  Rounds to less than $500.

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

  Various inputs are used in determining the value of the Fund's investments, following the input prioritization hierarchy established by GAAP. These inputs are summarized in the three broad levels listed below:

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

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

•  Level 3 – prices determined using significant unobservable inputs where quoted prices or observable inputs are unavailable or less reliable (including management's own assumptions about the factors market participants would use in pricing an investment)

  The inputs or methodology 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 Fund 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 Valuation Committee of the Fund's Board of Trustees that rely on significant observable inputs are also included in Level 2. Typical Level 3 securities include any security fair valued by the Valuation Committee that relies on significant unobservable inputs.

See accompanying notes to financial statements.

45

Columbia Acorn International

Statement of Investments (Unaudited), continued

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

The following table summarizes the inputs used, as of June 30, 2011, 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	$	65,833	$	2,341,862		$	-	$	2,407,695
Asia		162,969		2,207,288			-		2,370,257
Other Countries		541,710		475,626			-		1,017,336
Latin America		332,993		9,219			15,000		357,212
Total Equities		1,103,505		5,033,995			15,000		6,152,500
Total Securities Lending Collateral		90,621		-			-		90,621
Total Short-Term Obligation		-		226,923			-		226,923
Total Investments	$	1,194,126	$	5,260,918		$	15,000	$	6,470,044
Unrealized Appreciation on Forward Foreign Currency Exchange Contracts		-		3,057			-		3,057
Unrealized Depreciation on Forward Foreign Currency Exchange Contracts		-		(2,796	)		-		(2,796	)
Total	$	1,194,126	$	5,261,179		$	15,000	$	6,470,305

  The Fund's assets assigned to the Level 2 input category are generally valued using a market approach, in which a security's value is determined through its correlation to prices and information from observable market transactions for similar or identical assets. Foreign equities are generally valued at the last sales price on the foreign exchange or market on which they trade. The Fund may use a systematic fair valuation model provided by an independent third party to value securities principally traded in foreign markets in order to adjust for possible stale pricing that may occur between the close of the foreign exchanges and the time for valuation. These models take into account available market data including intraday index, ADR, and ETF movements. Forward foreign currency exchange contracts are valued at the prevailing forward exchange rate of the underlying currencies. Securities acquired via private placement that have a holding period or an extended settlement period are valued at a discount to the same shares that are trading freely on the market. These discounts are determined by the adviser's experience with similar securities or situations. Factors may include, but are not limited to, trade volume, shares outstanding and stock price.

  Certain short-term obligations may be valued using amortized cost, an income approach which converts future cash flows to a present value based upon the discount or premium at purchase.

  The Fund's assets assigned to the Level 3 input category are valued at fair value as determined in good faith under consistently applied procedures established by and under the general supervision of the Board of Trustees. To determine fair value, management will utilize the valuation technique that they deem the most appropriate in the circumstances. Securities acquired via private placement that are not yet trading are valued using a market approach for which management has determined that the original transaction price is the best representation of fair value. The original cost may be adjusted for the market movement in an index, ETF or similar security during the period it does not trade.

The following table shows transfers between Level 1 and Level 2 of the fair value hierarchy.

Transfers In				Transfers Out
Level 1		Level 2		Level 1		Level 2
$	263,663	$	13,490	$	13,490	$	263,663

  Financial assets were transferred from Level 2 to Level 1 as they resumed trading during the period.

  Foreign exchange-traded financial assets were transferred from Level 1 to Level 2.

  The following table reconciles asset balances for the six months ending June 30, 2011, in which significant unobservable inputs (Level 3) were used in determining value:

Investments in Securities	Balance as of December 31, 2010		Realized Gain/(Loss)			Change in Unrealized Appreciation (Depreciation)		Purchases		Sales		Transfers into Level 3		Transfers out of Level 3		Balance as of June 30, 2011
Equities
Asia	$	79	$	(38,558	)	$	38,479	$	-	$	-	$	-	$	-	$	-
Latin America		15,000		-			-		-		-		-		-		15,000
	$	15,079	$	(38,558	)	$	38,479	$	-	$	-	$	-	$	-	$	15,000

  The information in the above reconciliation table represents fiscal year to date activity for any securities identified as using Level 3 inputs at either the beginning or the end of the current fiscal period.

  The change in unrealized appreciation (depreciation) attributed to securities owned at June 30, 2011, which were valued using significant unobservable inputs (Level 3) amounted to $38,479. This amount is included in net change in unrealized appreciation (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.

46

Columbia Acorn International

Portfolio Diversification (Unaudited)

At June 30, 2011, 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	$	541,127		8.4
Machinery		469,283		7.3
Industrial Materials & Specialty Chemicals		459,670		7.1
Electrical Components		130,742		2.0
Conglomerates		103,870		1.6
Construction		87,084		1.4
Outsourcing Services		50,077		0.8
Industrial Distribution		19,391		0.3
		1,861,244		28.9
> Consumer Goods & Services
Retail		247,635		3.9
Food & Beverage		189,620		2.9
Casinos & Gaming		181,242		2.8
Nondurables		147,738		2.3
Apparel		118,771		1.8
Other Consumer Services		112,523		1.7
Travel		107,797		1.7
Other Entertainment		49,541		0.8
Educational Services		41,991		0.7
Consumer Goods Distribution		18,445		0.3
		1,215,303		18.9
> Energy & Minerals
Mining		290,874		4.5
Oil Services		262,762		4.1
Oil & Gas Producers		120,004		1.8
Oil Refining, Marketing & Distribution		88,879		1.4
Agricultural Commodities		75,308		1.2
		837,827		13.0
> Information
Instrumentation		146,256		2.3
Internet Related		141,016		2.2
Computer Hardware & Related Equipment		112,699		1.8
Business Software		93,992		1.5
Financial Processors		78,273		1.2
Mobile Communications		51,592		0.8
Telephone and Data Services		45,463		0.7
Computer Services		30,956		0.5
Gaming Equipment & Services		29,621		0.5
CATV		26,875		0.4
Telecommunications Equipment		24,845		0.4
Semiconductors & Related Equipment		19,409		0.3
Advertising		10,116		0.2
		811,113		12.8

	Value (000)			Percentage of Net Assets
> Other Industries
Real Estate	$	361,797			5.6
Transportation		163,746			2.5
Regulated Utilities		100,687			1.6
		626,230			9.7
> Finance
Banks		162,412			2.5
Brokerage & Money Management		137,955			2.1
Finance Companies		93,321			1.5
Insurance		63,547			1.0
		457,235			7.1
> Health Care
Medical Equipment & Devices		136,817			2.1
Pharmaceuticals		98,980			1.5
Medical Supplies		41,365			0.6
Health Care Services		35,231			0.5
Biotechnology & Drug Delivery		31,155			0.5
		343,548			5.2
Total Equities:		6,152,500			95.6
Securities Lending Collateral:		90,621			1.4
Short-Term Obligation:		226,923			3.5
Total Investments:		6,470,044			100.5
Obligation to Return Collateral for Securities Loaned:		(90,621	)		(1.4	)
Cash and Other Assets Less Liabilities:		60,237			0.9
Net Assets:	$	6,439,660			100.0

See accompanying notes to financial statements.

47

Columbia Acorn USA

Major Portfolio Changes in the Second Quarter (Unaudited)

	Number of Shares
	03/31/11		06/30/11
Purchases
Consumer Goods & Services
HomeAway		0		30,000
Industrial Goods & Services
Drew Industries		326,000		496,000
ESCO Technologies		735,000		835,000
HEICO		403,732		504,665
Nordson		373,600		747,200
Finance
Enstar Group		0		39,000
Hancock Holding		40,000		278,678
TrustCo Bank		0		245,300
Health Care
Akorn		676,582		725,000
Auxilium Pharmaceuticals		205,000		375,000
Community Health Systems		0		151,000
Isis Pharmaceuticals		626,000		850,000
Kindred Healthcare		0		150,000
United Therapeutics		65,000		102,000
Energy & Minerals
FMC Technologies		500,000		1,000,000
Swift Energy		84,000		168,000
Other Industries
Rush Enterprises, Class A		210,091		410,091

	Number of Shares
	03/31/11		06/30/11
Sales
Information
Acxiom		172,000		0
Blue Coat Systems		197,000		0
Crown Castle International		150,000		0
Equinix		44,000		0
SRA International		261,000		0
Supertex		177,266		0
Consumer Goods & Services
Chico's FAS		614,000		481,000
Express		104,508		0
ITT Educational Services		153,700		37,350
Knoll		980,000		880,000
Vail Resorts		150,000		71,000
Wet Seal		620,000		0
Industrial Goods & Services
American Reprographics		396,000		0
Mueller Water Products		550,000		204,200
Finance
GATX		240,000		42,400
Investment Technology Group		139,400		0
Tower Group		222,000		0
Valley National Bancorp		981,941		931,000
Whitney Holding		571,000		0
Wilmington Trust		245,000		0
Health Care
Allos Therapeutics		446,532		0
American Medical Systems		72,000		0
Idenix Pharmaceuticals		428,965		0
Nektar Therapeutics		146,710		0
Energy & Minerals
Atwood Oceanics		845,000		803,000
Carrizo Oil & Gas		146,000		73,000
Hornbeck Offshore		101,000		0
Tesco		53,000		0

See accompanying notes to financial statements.

48

Columbia Acorn USA

Statement of Investments (Unaudited), June 30, 2011

Number of Shares			Value (000)
			Equities: 99.4%
Information 34.1%
		> Business Software 9.7%
	985,000	Informatica (a)	$	57,554
		Enterprise Data Integration Software
	698,000	Micros Systems (a)		34,698
		Information Systems for Hotels, Restaurants & Retailers
	375,000	ANSYS (a)		20,501
		Simulation Software for Engineers & Designers
	408,000	Ariba (a)		14,064
		Cost Management Software
	243,000	Concur Technologies (a)		12,167
		Web Enabled Cost & Expense Management Software
	247,000	Blackboard (a)(b)		10,717
		Education Software
	333,000	Blackbaud		9,231
		Software & Services for Non-profits
	220,000	Advent Software (a)		6,197
		Asset Management & Trading Systems
	322,000	SPS Commerce (a)		5,728
		Supply Chain Management Software Delivered via the Web
	129,000	NetSuite (a)		5,057
		End to End IT Systems Solutions Delivered Over the Web
	198,000	Constant Contact (a)		5,025
		E-mail & Other Marketing Campaign Management Systems Delivered Over the Web
	52,000	Quality Systems		4,540
		IT Systems for Medical Groups & Ambulatory Care Centers
				185,479
		> Instrumentation 4.7%
	678,000	IPG Photonics (a)		49,297
		Fiber Lasers
	180,000	Mettler Toledo (a)		30,361
		Laboratory Equipment
	168,000	Trimble Navigation (a)		6,660
		GPS-based Instruments
	130,000	FLIR Systems		4,382
		Infrared Cameras
				90,700
		> Semiconductors & Related Equipment 4.4%
	1,958,000	Atmel (a)		27,549
		Microcontrollers, Radio Frequency & Memory Semiconductors
	760,000	Microsemi (a)		15,580
		Analog/Mixed-signal Semiconductors
	1,061,750	ON Semiconductor (a)		11,117
		Mixed-signal & Power Management Semiconductors
	1,075,000	TriQuint Semiconductor (a)		10,954
		Radio Frequency Semiconductors
	675,000	Entegris (a)		6,831
		Semiconductor Materials Management Products

Number of Shares			Value (000)
	346,000	Monolithic Power Systems (a)	$	5,336
		High Performance Analog & Mixed-signal Integrated Circuits (ICs)
	448,000	Applied Micro Circuits (a)		3,969
		Communications Semiconductors
	430,000	Pericom Semiconductor (a)		3,844
		Interface Integrated Circuits (ICs) & Frequency Control Products
				85,180
		> Computer Hardware & Related Equipment 3.9%
	1,238,000	II-VI (a)		31,693
		Laser Optics & Specialty Materials
	324,000	Zebra Technologies (a)		13,663
		Bar Code Printers
	196,000	Amphenol		10,582
		Electronic Connectors
	280,000	Nice Systems - ADR (Israel) (a)		10,181
		Audio & Video Recording Solutions
	196,000	Netgear (a)		8,569
		Networking Products for Small Business & Home
				74,688
		> Telephone and Data Services 2.9%
	1,617,000	tw telecom (a)		33,197
		Fiber Optic Telephone/Data Services
	168,800	AboveNet		11,893
		Metropolitan Fiber Communications Services
	2,030,000	PAETEC Holding (a)		9,724
		Telephone/Data Services for Business
				54,814
		> Telecommunications Equipment 2.9%
	386,000	Polycom (a)		24,820
		Video Conferencing Equipment
	732,000	Finisar (a)		13,198
		Optical Sub-systems & Components
	903,000	Ixia (a)		11,558
		Telecom Network Test Equipment
	752,000	Infinera (a)		5,196
		Optical Networking Equipment
				54,772
		> Gaming Equipment & Services 1.8%
	660,000	Bally Technologies (a)		26,849
		Slot Machines & Software
	235,000	WMS Industries (a)		7,219
		Slot Machine Provider
				34,068
		> Mobile Communications 1.3%
	650,000	SBA Communications (a)		24,824
		Communications Towers
				24,824
		> Computer Services 1.0%
	428,000	ExlService Holdings (a)		9,887
		BPO (Business Process Outsourcing)
	1,005,500	Hackett Group (a)		5,118
		IT Integration & Best Practice Research

See accompanying notes to financial statements.

49

Columbia Acorn USA

Statement of Investments (Unaudited), continued

Number of Shares			Value (000)
		> Computer Services—continued
	710,000	RCM Technologies (a)(c)	$	3,798
		Technology & Engineering Services
				18,803
		> Financial Processors 0.5%
	188,000	Global Payments		9,588
		Credit Card Processor
				9,588
		> Contract Manufacturing 0.5%
	261,000	Plexus (a)		9,085
		Electronic Manufacturing Services
				9,085
		> Entertainment Programming 0.2%
	145,000	IMAX (Canada) (a)		4,702
		IMAX Movies, Theatre Equipment & Theatre Joint Ventures
				4,702
		> Radio 0.1%
	511,100	Salem Communications		1,835
		Radio Stations for Religious Programming
	71,718	Spanish Broadcasting System (a)		50
		Spanish Language Radio Stations
				1,885
		> TV Broadcasting 0.1%
	975,000	Entravision Communications (a)		1,804
		Spanish Language TV & Radio Stations
				1,804
		> Internet Related 0.1%
	343,000	TheStreet.com		1,053
		Financial Information Websites
				1,053
Information: Total				651,445
Consumer Goods & Services 16.9%
		> Retail 6.2%
	390,000	lululemon athletica (a)		43,610
		Premium Active Apparel Retailer
	468,500	Abercrombie & Fitch		31,352
		Teen Apparel Retailer
	254,000	Shutterfly (a)		14,585
		Internet Photo-centric Retailer
	875,000	Saks (a)		9,774
		Luxury Department Store Retailer
	805,000	Pier 1 Imports (a)		9,314
		Home Furnishing Retailer
	481,000	Chico's FAS		7,325
		Women's Specialty Retailer
	480,000	Talbots (a)(b)		1,603
		Women's Specialty Retailer
	9,000	The Fresh Market (a)		348
		Specialty Food Retailer
				117,911
		> Travel 3.2%
	849,700	Gaylord Entertainment (a)		25,491
		Convention Hotels

Number of Shares			Value (000)
	1,175,950	Avis Budget Group (a)	$	20,097
		Second Largest Car Rental Company
	750,000	Hertz (a)		11,910
		Largest U.S. Rental Car Operator
	71,000	Vail Resorts		3,282
		Ski Resort Operator & Developer
	30,000	HomeAway (a)		1,161
		Vacation Rental Online Marketplace
				61,941
		> Furniture & Textiles 1.9%
	880,000	Knoll		17,662
		Office Furniture
	540,000	Interface		10,460
		Modular & Broadloom Carpet
	260,000	Herman Miller		7,077
		Office Furniture
				35,199
		> Apparel 1.3%
	192,000	Warnaco Group (a)		10,032
		Global Branded Apparel Manufacturer
	90,000	Deckers Outdoor (a)		7,932
		Fashion Footwear Wholesaler
	241,530	True Religion Apparel (a)		7,024
		Premium Denim
				24,988
		> Casinos & Gaming 1.1%
	270,000	Penn National Gaming (a)		10,892
		Regional Casino Operator
	645,000	Pinnacle Entertainment (a)		9,610
		Regional Casino Operator
				20,502
		> Food & Beverage 0.8%
	197,000	Diamond Foods (b)		15,039
		Snack Foods & Culinary Ingredients
				15,039
		> Consumer Goods Distribution 0.7%
	472,000	Pool		14,070
		Distributor of Swimming Pool Supplies & Equipment
				14,070
		> Other Durable Goods 0.6%
	161,000	Cavco Industries (a)		7,245
		Manufactured Homes
	140,000	Jarden		4,831
		Branded Household Products
				12,076
		> Other Consumer Services 0.5%
	259,000	Lifetime Fitness (a)		10,337
		Sport & Fitness Club Operator
				10,337
		> Educational Services 0.3%
	165,000	Universal Technical Institute		3,262
		Vocational Training
	37,350	ITT Educational Services (a)		2,922
		Post-secondary Degree Services
				6,184

See accompanying notes to financial statements.

50

Number of Shares			Value (000)
		> Leisure Products 0.3%
	162,000	Thor Industries	$	4,672
		RV & Bus Manufacturer
				4,672
		> Restaurants —%
	26,600	Bravo Brio Restaurant Group (a)		650
		Upscale Casual Italian Restaurants
				650
Consumer Goods & Services: Total				323,569
Industrial Goods & Services 15.1%
		> Machinery 11.6%
	941,250	Ametek		42,262
		Aerospace/Industrial Instruments
	747,200	Nordson		40,984
		Dispensing Systems for Adhesives & Coatings
	835,000	ESCO Technologies		30,728
		Automatic Electric Meter Readers
	445,000	Donaldson		27,003
		Industrial Air Filtration
	585,000	Pentair		23,611
		Pumps & Water Treatment
	504,665	HEICO		20,065
		FAA Approved Aircraft Replacement Parts
	280,000	MOOG (a)		12,186
		Motion Control Products for Aerospace, Defense & Industrial Markets
	177,000	Kennametal		7,471
		Consumable Cutting Tools
	100,000	WABCO Holdings (a)		6,906
		Truck & Bus Component Supplier
	162,000	Oshkosh (a)		4,688
		Specialty Truck Manufacturer
	71,800	Toro		4,344
		Turf Maintenance Equipment
	50,000	Kaydon		1,866
		Specialized Friction & Motion Control Products
				222,114
		> Industrial Materials & Specialty Chemicals 1.0%
	496,000	Drew Industries		12,261
		RV & Manufactured Home Components
	54,000	Albemarle		3,737
		Refinery Catalysts & Other Specialty Chemicals
	135,000	Albany International		3,563
		Paper Machine Clothing & Advanced Textiles
				19,561
		> Electrical Components 0.8%
	280,000	Acuity Brands		15,618
		Commercial Lighting Fixtures
				15,618
		> Steel 0.5%
	486,000	GrafTech International (a)		9,851
		Industrial Graphite Materials Producer
				9,851

Number of Shares			Value (000)
		> Other Industrial Services 0.4%
	265,000	TrueBlue (a)	$	3,837
		Temporary Manual Labor
	109,000	Forward Air		3,683
		Freight Transportation Between Airports
				7,520
		> Industrial Distribution 0.4%
	350,000	Interline Brands (a)		6,430
		Industrial Distribution
				6,430
		> Waste Management 0.3%
	195,000	Waste Connections		6,187
		Solid Waste Management
				6,187
		> Water 0.1%
	204,200	Mueller Water Products		813
		Fire Hydrants, Valves & Ductile Iron Pipes
				813
Industrial Goods & Services: Total				288,094
Finance 9.9%
		> Banks 4.9%
	931,000	Valley National Bancorp		12,671
		New Jersey/New York Bank
	170,000	SVB Financial Group (a)		10,151
		Bank to Venture Capitalists
	692,400	Associated Banc-Corp		9,624
		Midwest Bank
	431,597	Lakeland Financial		9,607
		Indiana Bank
	480,000	MB Financial		9,235
		Chicago Bank
	659,800	TCF Financial		9,105
		Great Lakes Bank
	278,678	Hancock Holding		8,633
		Gulf Coast Bank
	1,478,200	First Busey		7,820
		Illinois Bank
	527,700	Pacific Continental		4,828
		Pacific Northwest Bank
	269,600	Eagle Bancorp (a)		3,586
		Metro D.C. Bank
	178,826	Sandy Spring Bancorp		3,217
		Baltimore/D.C. Bank
	210,000	CVB Financial		1,943
		Inland Empire Business Bank
	90,000	TriCo Bancshares		1,314
		California Central Valley Bank
	245,300	TrustCo Bank		1,202
		New York State Bank
	851,247	Guaranty Bancorp (a)		1,141
		Colorado Bank
				94,077
		> Finance Companies 3.3%
	345,000	World Acceptance (a)		22,622
		Personal Loans

See accompanying notes to financial statements.

51

Columbia Acorn USA

Statement of Investments (Unaudited), continued

Number of Shares			Value (000)
		> Finance Companies—continued
	412,500	Aaron's	$	11,657
		Rent to Own
	335,418	McGrath Rentcorp		9,418
		Temporary Space & IT Rentals
	285,000	Textainer Group Holdings		8,761
		Top International Container Leasor
	230,000	CAI International (a)		4,752
		International Container Leasing
	201,000	H&E Equipment Services (a)		2,812
		Heavy Equipment Leasing
	42,400	GATX		1,574
		Rail Car Lessor
	99,200	Marlin Business Services (a)		1,255
		Small Equipment Leasing
				62,851
		> Savings & Loans 0.9%
	756,000	ViewPoint Financial		10,433
		Texas Thrift
	215,000	Berkshire Hills Bancorp		4,814
		Northeast Thrift
	173,073	Kaiser Federal Financial Group		2,132
		Los Angeles Savings & Loan
				17,379
		> Brokerage & Money Management 0.6%
	209,500	Eaton Vance		6,333
		Specialty Mutual Funds
	675,000	MF Global (a)		5,225
		Futures Broker
				11,558
		> Insurance 0.2%
	39,000	Enstar Group (a)		4,075
		Insurance/Reinsurance & Related Services
				4,075
Finance: Total				189,940
Health Care 8.8%
		> Biotechnology & Drug Delivery 4.4%
	520,000	BioMarin Pharmaceutical (a)		14,149
		Biotech Focused on Orphan Diseases
	491,882	Seattle Genetics (a)		10,094
		Antibody-based Therapies for Cancer
	232,000	Onyx Pharmaceuticals (a)		8,190
		Commercial-stage Biotech Focused on Cancer
	840,000	NPS Pharmaceuticals (a)		7,938
		Orphan Drugs & Healthy Royalties
	850,000	Isis Pharmaceuticals (a)		7,786
		Biotech Pioneer in Anti-sense Drugs
	375,000	Auxilium Pharmaceuticals (a)		7,350
		Biotech Focused on Niche Disease Areas
	196,000	InterMune (a)		7,027
		Drugs for Pulmonary Fibrosis & Hepatitis C
	102,000	United Therapeutics (a)		5,620
		Biotech Focused on Rare Diseases
	810,000	Micromet (a)		4,649
		Next-generation Antibody Technology

Number of Shares			Value (000)
	790,000	Chelsea Therapeutics (a)	$	4,029
		Biotech Focused on Rare Diseases
	455,000	Nabi Biopharmaceuticals (a)		2,448
		Biotech Focused on Vaccines
	265,000	Anthera Pharmaceuticals (a)		2,165
		Biotech Focused on Cardiovascular, Cancer & Immunology
	243,000	Savient Pharmaceuticals (a)(b)		1,820
		Biotech Focused on Severe Gout
	450,000	Array Biopharma (a)		1,008
		Drugs for Cancer & Inflammatory Diseases
	18,181	Metabolex, Series A-1 (a)(d)		18
		Diabetes Drug Development
	738,060	Medicure - Warrants (a)(d)		—
		Cardiovascular Biotech Company
	37,500	Locus Pharmaceuticals, Series A-1, Pfd. (a)(d)		—
	19,329	Locus Pharmaceuticals, Series B-1, Pfd. (a)(d)		—
		High Throughput Rational Drug Design
				84,291
		> Medical Equipment & Devices 2.2%
	370,000	Alexion Pharmaceuticals (a)		17,401
		Biotech Focused on Orphan Diseases
	184,000	Sirona Dental Systems (a)		9,770
		Manufacturer of Dental Equipment
	124,000	Gen-Probe (a)		8,575
		Molecular In-vitro Diagnostics
	53,000	Idexx Laboratories (a)		4,111
		Diagnostic Equipment & Services for Veterinarians
	155,000	Pacific Biosciences of California (a)		1,813
		Genome Sequencing
				41,670
		> Medical Supplies 0.9%
	439,600	Cepheid (a)		15,228
		Molecular Diagnostics
	49,000	Neogen (a)		2,215
		Food & Animal Safety Products
				17,443
		> Health Care Services 0.8%
	1,038,900	Health Management Associates (a)		11,199
		Non-urban Hospitals
	151,000	Community Health Systems (a)		3,878
		Non-urban Hospitals
				15,077
		> Pharmaceuticals 0.3%
	725,000	Akorn (a)		5,075
		Develops, Manufactures & Sells Specialty Generic Drugs
	108,512	Alimera Sciences (a)		884
		Ophthalmogy-focused Pharmaceutical Company
				5,959
		> Hospital Management 0.2%
	150,000	Kindred Healthcare (a)		3,221
		Post-Acute Healthcare Facilities
				3,221
Health Care: Total				167,661

See accompanying notes to financial statements.

52

Number of Shares			Value (000)
Energy & Minerals 8.2%
		> Oil Services 4.4%
	1,000,000	FMC Technologies (a)	$	44,790
		Oil & Gas Wellhead Manufacturer
	803,000	Atwood Oceanics (a)		35,436
		Offshore Drilling Contractor
	86,000	Bristow		4,388
		Largest Provider of Helicopter Services to Offshore Oil & Gas Producers
				84,614
		> Oil & Gas Producers 2.9%
	1,135,000	Quicksilver Resources (a)		16,753
		Natural Gas & Coal Steam Gas Producer
	133,000	SM Energy		9,773
		Oil & Gas Producer
	143,000	Rosetta Resources (a)		7,370
		Oil & Gas Producer Exploring in South Texas & Montana
	386,000	Houston American Energy (b)		6,998
		Oil & Gas Exploration & Production in Colombia
	168,000	Swift Energy (a)		6,261
		Oil & Gas Exploration & Production Company
	230,000	Northern Oil & Gas (a)(b)		5,094
		Small E&P Company in North Dakota Bakken
	73,000	Carrizo Oil & Gas (a)		3,048
		Oil & Gas Producer
	22,800	Oasis Petroleum (a)		677
		Oil Producer in North Dakota
				55,974
		> Mining 0.9%
	100,000	Core Laboratories (Netherlands)		11,154
		Oil & Gas Reservoir Consulting
	600,000	Alexco Resource (a)		4,326
		Mining, Exploration & Environmental Services
	180,000	Augusta Resource (a)		834
		U.S. Copper/Molybdenum Mine
				16,314
Energy & Minerals: Total				156,902
Other Industries 6.4%
		> Real Estate 5.2%
	915,000	Extra Space Storage		19,517
		Self Storage Facilities
	995,200	BioMed Realty Trust		19,148
		Life Science-focused Office Buildings
	600,000	Associated Estates Realty		9,750
		Multi-family Properties
	246,000	Corporate Office Properties		7,653
		Office Buildings
	870,000	Education Realty Trust		7,456
		Student Housing
	177,000	Kilroy Realty		6,990
		West Coast Office & Industrial Properties
	1,380,000	Kite Realty Group		6,872
		Community Shopping Centers
	1,058,000	DCT Industrial Trust		5,533
		Industrial Properties

Number of Shares or Principal Amount			Value (000)
	98,619	Macerich	$	5,276
		Regional Shopping Malls
	191,000	Dupont Fabros Technology (b)		4,813
		Technology-focused Office Buildings
	100,000	Post Properties		4,076
		Multi-family Properties
	208,000	Summit Hotel Properties		2,361
		Owner of Select Service Hotels
				99,445
		> Transportation 1.2%
	410,091	Rush Enterprises, Class A (a)		7,804
	115,000	Rush Enterprises, Class B (a)		1,851
		Truck Sales & Services
	256,000	World Fuel Services		9,198
		Global Fuel Broker
	310,000	Heartland Express		5,134
		Regional Trucker
				23,987
Other Industries: Total				123,432
Total Equities: 99.4% (Cost: $1,231,445)				1,901,043
Securities Lending Collateral: 0.7%
	12,943,711	Dreyfus Government Cash Management Fund (e) (7 day yield of 0.00%)		12,944
Total Securities Lending Collateral: (Cost: $12,944)				12,944
Short-Term Obligation: 0.8%
		> Repurchase Agreement: 0.8%
$	15,821	Repurchase Agreement with Fixed Income Clearing Corp., dated 6/30/11, due 7/01/11 at 0.01%, collateralized by a U.S. Government Agency obligation maturing 8/18/17, market value $16,141 (repurchase proceeds $15,821)		15,821
Total Short Term Obligation: (Cost: $15,821)				15,821
Total Investments: 100.9% (Cost: $1,260,210) (f)				1,929,808
Obligation to Return Collateral for Securities Loaned: (0.7)%				(12,944	)
Cash and Other Assets Less Liabilities: (0.2)%				(4,519	)
Total Net Assets: 100.0%			$	1,912,345

  ADR = American Depositary Receipts.

See accompanying notes to financial statements.

53

Columbia Acorn USA

Statement of Investments (Unaudited), 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 June 30, 2011. The total market value of Fund securities on loan at June 30, 2011 was $12,520.

(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 this affiliated company during the six months ended June 30, 2011, are as follows:

Affiliate	Balance of Shares Held 12/31/10		Purchases/ Additions		Sales/ Reductions		Balance of Shares Held 6/30/11		Value		Dividend
RCM Technologies		710,000		-		-		710,000	$	3,798	$	-
Total of Affiliated Transactions		710,000		-		-		710,000	$	3,798	$	-

  The aggregate cost and value of this affiliated company at June 30, 2011, was $4,479 and $3,798. Investments in this affiliated company represented 0.2% of total net assets at June 30, 2011.

(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 June 30, 2011, the market value of these securities amounted to $18, 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 -1	2/11/00		18,181	$	2,000	$	18
Medicure - Warrants	12/22/06		738,060		-		-
Locus Pharmaceuticals, Series A-1 Pfd.	9/05/01		37,500		1,500		-
Locus Pharmaceuticals, Series B-1 Pfd.	2/08/07		19,329		56		-
				$	3,556	$	18

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

(f)  At June 30, 2011, for federal income tax purposes, the cost of investments was $1,260,210 and net unrealized appreciation was $669,598, consisting of gross unrealized appreciation of $760,468 and gross unrealized depreciation of $90,870.

  Various inputs are used in determining the value of the Fund's investments, following the input prioritization hierarchy established by GAAP. These inputs are summarized in the three broad levels listed below:

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

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

•  Level 3 – prices determined using significant unobservable inputs where quoted prices or observable inputs are unavailable or less reliable (including management's own assumptions about the factors market participants would use in pricing an investment)

  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 Fund 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 Valuation Committee of the Fund's Board of Trustees that rely on significant observable inputs are also included in level 2. Typical Level 3 securities include any security fair valued by the Valuation Committee that relies on significant unobservable inputs.

See accompanying notes to financial statements.

54

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

The following table summarizes the inputs used, as June 30, 2011, 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	$	651,445	$	-	$	-	$	651,445
Consumer Goods & Services		323,569		-		-		323,569
Industrial Goods & Services		288,094		-		-		288,094
Finance		189,940		-		-		189,940
Health Care		167,643		-		18		167,661
Energy & Minerals		156,902		-		-		156,902
Other Industries		123,432		-		-		123,432
Total Equities		1,901,025		-		18		1,901,043
Total Securities Lending Collateral		12,944		-		-		12,944
Total Short-Term Obligation		-		15,821		-		15,821
Total Investments	$	1,913,969	$	15,821	$	18	$	1,929,808

  The Fund's assets assigned to the Level 2 input category are generally valued using the market approach, in which a security's value is determined through its correlation to prices and information from market transactions for similar or identical assets. Warrants which do not trade are valued as a percentage of the actively trading common stock using a model, based on Black Scholes.

  Certain short-term obligations may be valued using amortized cost, an income approach which converts future cash flows to a present value based upon the discount or premium at purchase.

  The Fund's assets assigned to the Level 3 input category are valued at fair value as determined in good faith under consistently applied procedures established by and under the general supervision of the Board of Trustees. To determine fair value, management will utilize the valuation technique that they deem the most appropriate in the circumstances. Securities for which no market exists are valued based upon a market approach using some unobservable inputs which may include, but are not limited to, projected earnings, available cash, line of business, multiples, and consideration of the prioritization of the equity in a company's capital structure.

  There were no significant transfers of financial assets between levels 1 and 2 during the period.

  The following table reconciles asset balances for the six months ending June 30, 2011, in which significant unobservable inputs (Level 3) were used in determining value:

Investments in Securities	Balance as of December 31, 2010		Realized Gain/(Loss)		Change in Unrealized Appreciation (Depreciation)			Purchases		Sells		Transfers into Level 3		Transfers out of Level 3		Balance as of June 30, 2011
Equities
Health Care	$	20	$	-	$	(2	)	$	-	$	-	$	-	$	-	$	18
	$	20	$	-	$	(2	)	$	-	$	-	$	-	$	-	$	18

  The information in the above reconciliation represents fiscal year to date activity for any securities identified as using Level 3 inputs at either the beginning or the end of the current fiscal period.

  The change in unrealized depreciation attributed to securities owned at June 30, 2011, which were valued using significant unobservable inputs (Level 3) amounted to $2. This amount is included in net change in unrealized appreciation (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.

55

Columbia Acorn International Select

Major Portfolio Changes in the Second Quarter (Unaudited)

	Number of Shares
	03/31/11		06/30/11
Purchases
Europe
> United Kingdom
Archipelago Resources		2,775,000		4,472,797
Chemring		1,465,000		1,609,133
JLT Group		517,000		881,100
> Netherlands
Imtech		231,504		235,519
> Germany
Rhoen-Klinikum		200,000		297,000
> Switzerland
Partners Group		0		24,000
> Belgium
EVS Broadcast Equipment		0		33,800
Asia
> Singapore
Ascendas REIT		11,105,000		13,130,000
Mapletree Industrial Trust REIT		0		14,601,100
> China
Want Want		0		1,655,000
Zhaojin Mining Industry		1,324,700		2,649,400
Other Countries
> South Africa
Rand Merchant Insurance		0		4,902,152

	Number of Shares
	03/31/11		06/30/11
Sales
Europe
> United Kingdom
Cobham		2,415,000		616,000
Intertek Group		412,000		400,000
Petropavlovsk		568,000		0
Serco		2,139,000		985,000
Workspace Group		13,437,411		9,710,000
> Netherlands
Fugro		175,427		117,121
> Sweeden
Hexagon		774,666		658,666
> Switzerland
Bank Sarasin & Cie		99,000		0
> Ireland
United Drug		3,213,000		2,377,800
> France
Neopost		130,000		48,000
> Spain
Red Eléctrica de España		80,000		0
Asia
> Japan
Benesse		15,400		0
Gree		521,000		280,000
> China
Jiangsu Expressway		12,115,400		6,727,000
> Hong Kong
Hutchison Port Holdings Trust		1,515,000		0
Other Countries
> Canada
Pan American Silver		132,000		0
> United States
Atwood Oceanics		143,000		112,000
> Austriala
UGL		571,848		540,000
Latin America
> Columbia
Pacific Rubiales Energy		525,000		260,000

See accompanying notes to financial statements.

56

Columbia Acorn International Select

Statement of Investments (Unaudited), June 30, 2011

Number of Shares			Value (000)
			Equities: 87.0%
Europe 41.3%
		> United Kingdom 13.9%
	1,609,133	Chemring	$	16,529
		Defense Manufacturer of Countermeasures & Energetics
	400,000	Intertek Group		12,666
		Testing, Inspection & Certification Services
	881,100	JLT Group		9,630
		International Business Insurance Broker
	985,000	Serco		8,734
		Facilities Management
	9,710,000	Workspace Group		4,714
		United Kingdom Real Estate
	4,472,797	Archipelago Resources (a)		4,433
		Gold Mining Projects in Indonesia, Vietnam & the Philippines
	616,000	Cobham		2,092
		Aerospace Components
	226,800	Shaftesbury		1,922
		London Prime Retail REIT
				60,720
		> Netherlands 8.7%
	166,000	AkzoNobel		10,472
		Largest Global Supplier of Protective Paints & Coatings
	117,121	Fugro		8,445
		Sub-sea Oilfield Services
	235,519	Imtech		8,330
		Electromechanical & Information & Communications Technologies Installation & Maintenance
	242,103	Aalberts Industries		5,659
		Flow Control & Heat Treatment
	45,000	Core Laboratories		5,019
		Oil & Gas Reservoir Consulting
				37,925
		> Germany 6.7%
	672,000	Wirecard		12,011
		Online Payment Processing & Risk Management
	115,500	Rheinmetall		10,225
		Defense & Automotive
	297,000	Rhoen-Klinikum		7,167
		Health Care Services
				29,403
		> Sweden 3.7%
	658,666	Hexagon		16,224
		Measurement Equipment & Software
				16,224
		> Switzerland 2.7%
	51,000	Kuehne & Nagel		7,740
		Freight Forwarding/Logistics
	24,000	Partners Group		4,248
		Private Markets Asset Management
				11,988

Number of Shares			Value (000)
		> Ireland 1.9%
	2,377,800	United Drug	$	8,145
		Irish Pharmaceutical Wholesaler & Outsourcer
				8,145
		> Iceland 1.2%
	4,800,000	Marel (a)		5,081
		Largest Manufacturer of Poultry & Fish Processing Equipment
				5,081
		> Denmark 1.1%
	29,000	Novozymes		4,719
		Industrial Enzymes
				4,719
		> France 0.9%
	48,000	Neopost		4,123
		Postage Meter Machines
				4,123
		> Belgium 0.5%
	33,800	EVS Broadcast Equipment		2,288
		Digital Live Mobile Production Software & Systems
				2,288
Europe: Total				180,616
Asia 29.1%
		> Japan 13.5%
	2,115,000	Kansai Paint		19,270
		Paint Producer in Japan, India, China & Southeast Asia
	480,000	Asahi Diamond Industrial		10,494
		Consumable Diamond Tools
	8,550	Jupiter Telecommunications		9,566
		Largest Cable Service Provider in Japan
	4,450	Seven Bank		8,892
		ATM Processing Services
	280,000	Gree (a)		6,121
		Mobile Social Networking Game Developer/Platform
	110,000	Ain Pharmaciez		4,526
		Dispensing Pharmacy/Drugstore Operator
				58,869
		> Singapore 8.2%
	13,130,000	Ascendas REIT		21,838
		Industrial Property Landlord
	14,601,100	Mapletree Industrial Trust REIT		13,923
		Industrial Property Landlord
				35,761
		> South Korea 4.4%
	79,266	NHN (a)		14,053
		South Korea's Largest Online Search Engine
	151,000	Woongjin Coway		5,385
		South Korean Household Appliance Rental Service Provider
				19,438

See accompanying notes to financial statements.

57

Columbia Acorn International Select

Statement of Investments (Unaudited), continued

Number of Shares			Value (000)
		> China 3.0%
	6,727,000	Jiangsu Expressway	$	6,167
		Chinese Toll Road Operator
	2,649,400	Zhaojin Mining Industry		5,466
		Gold Mining & Refining in China
	1,655,000	Want Want		1,607
		Chinese Branded Consumer Food Company
				13,240
Asia: Total				127,308
Other Countries 14.2%
		> South Africa 6.0%
	1,152,200	Adcock Ingram Holdings		10,123
		Manufacturer of Pharmaceuticals & Medical Supplies
	4,902,152	Rand Merchant Insurance		8,954
		Directly Sold Property & Casualty Insurance; Holdings in Other Insurers
	122,700	Naspers		6,931
		Media in Africa, China, Russia & Other Emerging Markets
				26,008
		> Canada 3.0%
	210,400	CCL Industries		7,234
		Leading Global Label Manufacturer
	125,000	AG Growth		5,936
		Leading Manufacturer of Augers & Grain Handling Equipment
				13,170
		> United States 2.3%
	112,000	Atwood Oceanics (a)		4,943
		Offshore Drilling Contractor
	67,000	SM Energy		4,923
		Oil & Gas Producer
				9,866
		> Australia 1.8%
	540,000	UGL		8,070
		Engineering & Facilities Management
				8,070
		> Israel 1.1%
	310,000	Israel Chemicals		4,947
		Producer of Potash, Phosphates, Bromine & Specialty Chemicals
				4,947
Other Countries: Total				62,061
Latin America 2.4%
		> Colombia 1.9%
	260,000	Pacific Rubiales Energy		6,969
		Oil Production & Exploration in Colombia
	18,800,000	Quetzal Energy (a)(b)		1,497
		Explores for Oil & Gas in Latin America
				8,466

Number of Shares or Principal Amount (000)			Value (000)
		> Argentina 0.5%
	1,000,000	Union Agriculture Group (a)(b)	$	2,200
		Farmland Operator in Uruguay
				2,200
Latin America: Total				10,666
Total Equities: 87.0% (Cost: $282,220)				380,651
Short-Term Obligation: 13.5%
		> Repurchase Agreement 13.5%
$	58,891	Repurchase Agreement with Fixed Income Clearing Corp., dated 6/30/11, due 7/01/11 at 0.01%, collateralized by a U.S. Government Agency obligation maturing 9/08/17, market value $60,070 (repurchase proceeds $58,891)		58,891
Total Short-Term Obligation 13.5% (Cost: $58,891)				58,891
Total Investments: 100.5% (Cost: $341,111)(c)(d)				439,542
Cash and Other Assets Less Liabilities: (0.5)%				(2,243	)
Total Net Assets: 100%			$	437,299

See accompanying notes to financial statements.

58

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

(a)  Non-income producing security.

(b)  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 June 30, 2011, the market value of these securities amounted to $3,697, which represented 0.85% of total net assets.

  Additional information on these securities is as follows:

Security	Acquisition Dates	Shares		Cost		Value
Union Agriculture Group	12/8/10		1,000,000	$	2,200	$	2,200
Quetzal Energy	1/14/11		18,800,000		2,376		1,497
				$	4,576	$	3,697

(c)  At June 30, 2011, for federal income tax purposes, the cost of investments was $341,111 and net unrealized appreciation was $98,431, consisting of gross unrealized appreciation of $103,528 and gross unrealized depreciation of $5,097.

(d)  On June 30, 2011, the Fund's total investments were denominated in currencies as follows:

Currency	Value		Percentage of Net Assets
Euro	$	76,865		17.6
U.S. Dollar		75,976		17.4
British Pound		60,720		13.9
Japanese Yen		58,869		13.5
Singapore Dollar		35,761		8.2
South African Rand		26,008		5.9
Other currencies less than 5% of total net assets		105,343		24.0
	$	439,542		100.5

  Various inputs are used in determining the value of the Fund's investments, following the input prioritization hierarchy established by GAAP. These inputs are summarized in the three broad levels listed below:

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

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

•  Level 3 – prices determined using significant unobservable inputs where quoted prices or observable inputs are unavailable or less reliable (including management's own assumptions about the factors market participants would use in pricing an investment)

  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 Fund 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 Valuation Committee of the Fund's Board of Trustees that rely on significant observable inputs are also included in level 2. Typical Level 3 securities include any security fair valued by the Valuation Committee that relies on significant unobservable inputs.

The following table summarizes the inputs used, as June 30, 2011, 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	$	5,019	$	175,597	$	-	$	180,616
Asia		-		127,308		-		127,308
Other Countries		23,036		39,025		-		62,061
Latin America		6,969		1,497		2,200		10,666
Total Equities		35,024		343,427		2,200		380,651
Total Short-Term Obligation		-		58,891		-		58,891
Total Investments	$	35,024	$	402,318	$	2,200	$	439,542

See accompanying notes to financial statements.

59

Columbia Acorn International Select

Statement of Investments (Unaudited), continued

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

  The Fund's assets assigned to the Level 2 input category are generally valued using the market approach, in which a security's value is determined through its correlation to prices and information from market transactions for similar or identical assets. Foreign equities are generally valued at the last sales price on the foreign exchange or market on which they trade. The Fund may use a systematic fair valuation model provided by an independent third party to value securities principally traded in foreign markets in order to adjust for possible stale pricing that may occur between the close of the foreign exchanges and the time for valuation. These models take into account available market data including intraday index, ADR, and ETF movements. Securities acquired via private placement that have a holding period or an extended settlement period are valued at a discount to the same shares that are trading freely on the market. These discounts are determined by the adviser's experience with similar securities or situations. Factors may include, but are not limited to, trade volume, shares outstanding and stock price.

  Certain short-term obligations may be valued using amortized cost, an income approach which converts future cash flows to a present value based upon the discount or premium at purchase.

  The Fund's assets assigned to the Level 3 input category are valued at fair value as determined in good faith under consistently applied procedures established by and under the general supervision of the Board of Trustees. To determine fair value, management will utilize the valuation technique that they deem the most appropriate in the circumstances. Securities acquired via private placement that are not yet trading are valued using a market approach for which management has determined that the original transaction price is the best representation of fair value. The original cost may be adjusted for the market movement in an index, ETF or similar security during the period it does not trade. Securities for which no market exists are valued based upon a market approach using some unobservable inputs which may include, but are not limited to, projected earnings, available cash, line of business, multiples and consideration of the prioritization of the equity in the company's capital structure.

  There were no significant transfers of financial assets between Levels 1 and 2 during the period.

  The following table reconciles asset balances for the six months ending June 30, 2011, in which significant unobservable inputs (Level 3) were used in determining value:

Investments in Securities	Balance as of December 31, 2010		Realized Gain/(Loss)		Change in Unrealized Appreciation (Depreciation)		Purchases		Sales		Transfers into Level 3		Transfers out of Level 3		Balance as of June 30, 2011
Latin America
Argentina	$	2,200	$	-	$	-	$	-	$	-	$	-	$	-	$	2,200
	$	2,200	$	-	$	-	$	-	$	-	$	-	$	-	$	2,200

  The information in the above reconciliation table represents fiscal year to date activity for any securities identified as using Level 3 inputs at either the beginning or the end of the current fiscal period.

  The change in unrealized appreciation (depreciation) attributed to securities owned at June 30, 2011, which were valued using significant unobservable inputs (Level 3) amounted to $0. This amount is included in net change unrealized appreciation (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.

60

Columbia Acorn International Select

Portfolio Diversification (Unaudited)

At June 30, 2011, the Fund's portfolio investments as a percentage of net assets were diversified as follows:

	Value (000)		Percentage of Net Assets
> Industrial Goods & Services
Industrial Materials & Specialty Chemicals	$	39,408		9.0
Other Industrial Services		36,806		8.4
Machinery		35,859		8.2
Electrical Components		18,621		4.3
Outsourcing Services		8,734		2.0
Conglomerates		5,659		1.3
		145,087		33.2
> Information
Internet Related		20,984		4.8
Instrumentation		16,224		3.7
Financial Processors		12,011		2.7
CATV		9,566		2.2
Gaming Equipment & Services		6,121		1.4
Business Software		2,288		0.5
		67,194		15.3
> Other Industries
Real Estate		42,397		9.7
Transportation		6,167		1.4
		48,564		11.1
> Energy & Minerals
Mining		14,918		3.4
Oil & Gas Producers		13,389		3.1
Oil Services		13,388		3.1
Agricultural Commodities		2,200		0.5
		43,895		10.1
> Finance
Insurance		18,584		4.2
Banks		8,892		2.0
Brokerage & Money Management		4,248		1.0
		31,724		7.2
> Health Care
Pharmaceuticals		18,268		4.2
Health Care Services		7,167		1.6
		25,435		5.8

	Value (000)			Percentage of Net Assets
> Consumer Goods & Services
Nondurables		7,234			1.7
Other Consumer Services		5,385			1.2
Retail		4,526			1.0
Food & Beverage		1,607			0.4
		18,752			4.3
Total Equities:		380,651			87.0
Short-Term Obligation:		58,891			13.5
Total Investments:		439,542			100.5
Cash and Other Assets Less Liabilities:		(2,243	)		(0.5	)
Net Assets:	$	437,299			100.0

See accompanying notes to financial statements.

61

Columbia Acorn Select

Major Portfolio Changes in the Second Quarter (Unaudited)

	Number of Shares
	03/31/11		06/30/11
Purchases
Consumer Goods & Services
Gaylord Entertainment		0		860,000
Industrial Goods & Services
Quanta Services		0		1,400,000
Information
Finisar		0		324,000
SBA Communications		505,000		755,000
WNS - ADR (India)		4,200,000		4,227,186
Energy & Minerals
Canadian Solar (China)		3,200,000		3,300,000
Health Care
Akorn		1,996,847		2,250,000

	Number of Shares
	03/31/11		06/30/11
Sales
Consumer Goods & Services
Abercrombie & Fitch		1,600,000		1,100,000
Career Education		1,900,000		0
Coach		1,135,000		1,025,000
Hertz		8,650,000		8,400,000
ITT Educational Services		1,000,000		325,000
Safeway		3,600,000		3,000,000
Thor Industries		720,000		0
Industrial Goods & Services
Ametek		1,860,000		1,830,000
ChemSpec International - ADR (China)		1,581,700		1,500,000
Donaldson		800,000		785,000
Nalco Holding Company		1,000,000		0
Pall		860,000		840,000
Waste Management		1,500,000		1,200,000
Information
American Tower		900,000		0
Crown Castle International		1,550,000		1,510,000
Navigant Consulting		2,300,000		813,073
Sanmina-SCI		7,100,000		6,950,000
VisionChina Media - ADR (China)		3,675,000		3,573,400
Energy & Minerals
Pacific Rubiales Energy (Colombia)		3,700,000		2,500,000
Synthesis Energy Systems (China)		4,426,330		3,850,372
Finance
CNO Financial Group		12,500,000		12,300,000
Discover Financial Services		5,150,000		5,050,000
MF Global		6,000,000		5,550,000
Other Industries
JB Hunt Transport Services		1,300,000		1,275,000

See accompanying notes to financial statements.

62

Columbia Acorn Select

Statement of Investments (Unaudited), June 30, 2011

Number of Shares			Value (000)
			Equities: 95.1%
Consumer Goods & Services 24.2%
		> Retail 9.9%
	1,100,000	Abercrombie & Fitch	$	73,612
		Teen Apparel Retailer
	3,000,000	Safeway		70,110
		Supermarkets
	350,000	lululemon athletica (a)(b)		39,137
		Premium Active Apparel Retailer
	250,000	Tiffany & Co.		19,630
		Luxury Good Retailer
				202,489
		> Travel 7.8%
	8,400,000	Hertz (a)		133,392
		Largest U.S. Rental Car Operator
	860,000	Gaylord Entertainment (a)		25,800
		Convention Hotels
				159,192
		> Apparel 3.2%
	1,025,000	Coach		65,528
		Designer & Retailer of Branded Leather Accessories
				65,528
		> Casinos & Gaming 1.6%
	335,000,000	RexLot Holdings (China)		32,405
		Lottery Equipment Supplier in China
				32,405
		> Educational Services 1.2%
	325,000	ITT Educational Services (a)(b)		25,428
		Post-secondary Degree Services
				25,428
		> Food & Beverage 0.3%
	1,000,000	GLG Life Tech (Canada) (a)		6,720
		Produce an All-natural Sweetener Extracted from the Stevia Plant
				6,720
		> Other Consumer Services 0.2%
	2,300,000	IFM Investments (Century 21 China RE) - ADR (China) (a)(c)		3,381
		Provides Real Estate Services in China
				3,381
Consumer Goods & Services: Total				495,143
Industrial Goods & Services 19.0%
		> Machinery 11.4%
	1,830,000	Ametek		82,167
		Aerospace/Industrial Instruments
	785,000	Donaldson		47,634
		Industrial Air Filtration
	840,000	Pall		47,233
		Filtration & Fluids Clarification
	885,000	Kennametal		37,356
		Consumable Cutting Tools
	650,000	Oshkosh (a)		18,811
		Specialty Truck Manufacturer
				233,201

Number of Shares			Value (000)
		> Waste Management 2.2%
	1,200,000	Waste Management	$	44,724
		U.S. Garbage Collection & Disposal
				44,724
		> Other Industrial Services 1.9%
	750,000	Expeditors International of Washington		38,392
		International Freight Forwarder
				38,392
		> Industrial Distribution 1.6%
	220,000	WW Grainger		33,803
		Industrial Distribution
				33,803
		> Outsourcing Services 1.4%
	1,400,000	Quanta Services (a)		28,280
		Electrical & Telecom Construction Services
				28,280
		> Industrial Materials & Specialty Chemicals 0.5%
	1,500,000	ChemSpec International - ADR (China) (a)		10,800
		Specialty Chemicals with Focus on Fluorinated Chemical Manufacturing
				10,800
Industrial Goods & Services: Total				389,200
Information 15.3%
		> Mobile Communications 5.3%
	1,510,000	Crown Castle International (a)		61,593
		Communications Towers
	755,000	SBA Communications (a)		28,833
		Communications Towers
	15,000,000	Globalstar (a)(b)(c)		18,450
		Satellite Mobile Voice & Data Carrier
				108,876
		> Contract Manufacturing 3.5%
	6,950,000	Sanmina-SCI (a)(c)		71,793
		Electronic Manufacturing Services
				71,793
		> Computer Hardware & Related Equipment 2.0%
	750,000	Amphenol		40,493
		Electronic Connectors
				40,493
		> Computer Services 1.8%
	4,227,186	WNS - ADR (India) (a)(c)		37,580
		Offshore BPO (Business Process Outsourcing) Services
				37,580
		> Instrumentation 1.0%
	120,000	Mettler Toledo (a)		20,240
		Laboratory Equipment
				20,240

See accompanying notes to financial statements.

63

Columbia Acorn Select

Statement of Investments (Unaudited), continued

Number of Shares			Value (000)
		> Advertising 0.5%
	3,573,400	VisionChina Media - ADR (China) (a)(b)	$	10,113
		Advertising on Digital Screens in China's Mass Transit System
				10,113
		> Business Software 0.5%
	182,000	Concur Technologies (a)		9,113
		Web Enabled Cost & Expense Management Software
				9,113
		> Business Information & Marketing Services 0.4%
	813,073	Navigant Consulting (a)		8,529
		Financial Consulting Firm
				8,529
		> Telecommunications Equipment 0.3%
	324,000	Finisar (a)		5,842
		Optical Sub-systems & Components
				5,842
Information: Total				312,579
Energy & Minerals 14.7%
		> Oil & Gas Producers 9.4%
	2,500,000	Pacific Rubiales Energy (Colombia)		67,007
		Oil Production & Exploration in Colombia
	30,530,000	Canacol Energy (Colombia) (a)(c)		33,555
	4,000,000	Canacol Energy (Colombia) (a)(c)(d)		4,308
		Oil Producer in South America
	38,343,900	ShaMaran Petroleum (Iraq) (a)(c)		30,216
		Oil Exploration in Kurdistan
	1,450,000	Houston American Energy (b)		26,288
		Oil & Gas Exploration & Production in Colombia
	34,856,000	Petrodorado (Colombia) (a)(c)		11,023
	17,144,000	Petrodorado - Warrants (Colombia) (a)(c)(d)		1,740
		Oil & Gas Exploration & Production in Colombia, Peru & Paraguay
	24,000,000	Canadian Overseas Petroleum (United Kingdom) (a)(c)(d)		11,096
	12,000,000	Canadian Overseas Petroleum - Warrants (United Kingdom) (a)(c)(d)		1,635
		Oil & Gas Exploration/Production in the North Sea
	13,125,000	Petromanas (Canada) (a)(d)		3,868
	5,000,000	Petromanas (Canada) (a)		1,503
	6,562,500	Petromanas - Warrants (Canada) (a)(d)		167
		Exploring for Oil in Albania
				192,406
		> Alternative Energy 2.4%
	3,300,000	Canadian Solar (China) (a)(b)(c)		37,950
		Solar Cell & Module Manufacturer
	3,850,372	Synthesis Energy Systems (China) (a)(b)(c)		7,200
		Owner/Operator of Gasification Plants
	1,600,000	Real Goods Solar (a)(c)		4,736
		Residential Solar Energy Installer
				49,886

Number of Shares			Value (000)
		> Agricultural Commodities 1.6%
	9,090,909	Union Agriculture Group (Argentina) (a)(d)	$	20,000
		Farmland Operator in Uruguay
	38,000,000	Eacom Timber (Canada) (a)(c)(d)		11,970
		Canadian Lumber Producer
				31,970
		> Mining 0.8%
	1,000,000	Kirkland Lake Gold (Canada) (a)		15,760
		Gold Mining
				15,760
		> Oil Services 0.5%
	10,885,700	Tuscany International Drilling (Colombia) (a)		10,384
	760,000	Tuscany International Drilling - Warrants (Colombia) (a)		28
		South America-based Drilling Rig Contractor
				10,412
Energy & Minerals: Total				300,434
Finance 14.7%
		> Credit Cards 6.6%
	5,050,000	Discover Financial Services		135,088
		Credit Card Company
				135,088
		> Insurance 4.8%
	12,300,000	CNO Financial Group (a)		97,293
		Life, Long-term Care & Medical Supplement Insurance
				97,293
		> Brokerage & Money Management 3.3%
	5,550,000	MF Global (a)		42,957
		Futures Broker
	1,100,000	SEI Investments		24,761
		Mutual Fund Administration & Investment Management
				67,718
Finance: Total				300,099
Other Industries 5.5%
		> Transportation 2.9%
	1,275,000	JB Hunt Transport Services		60,040
		Truck & Intermodal Carrier
				60,040
		> Real Estate 1.8%
	1,900,000	BioMed Realty Trust		36,556
		Life Science-focused Office Buildings
				36,556
		> Regulated Utilities 0.8%
	500,000	Wisconsin Energy		15,675
		Wisconsin Utility
				15,675
Other Industries: Total				112,271

See accompanying notes to financial statements.

64

Number of Shares or Principal Amount (000)			Value (000)
Health Care 1.7%
		> Biotechnology & Drug Delivery 0.9%
	2,000,000	NPS Pharmaceuticals (a)	$	18,900
		Orphan Drugs & Healthy Royalties
				18,900
		> Pharmaceuticals 0.8%
	2,250,000	Akorn (a)		15,750
		Develops, Manufactures & Sells Specialty Generic Drugs
				15,750
Health Care: Total				34,650
Total Equities: 95.1% (Cost: $1,465,678)				1,944,376
Securities Lending Collateral: 3.0%
	61,633,705	Dreyfus Government Cash Management Fund (e) (7 day yield of 0.00%)		61,634
Total Securities Lending Collateral: (Cost: $61,634)				61,634
Short-Term Obligation 4.6%
		> Repurchase Agreement 4.6%
$	94,733	Repurchase Agreement with Fixed Income Clearing Corp., dated 6/30/11, due 7/01/11 at 0.01%, collateralized by a U.S. Government Agency obligation maturing 8/18/17, market value $96,628 (repurchase proceeds $94,733)		94,733
				94,733
Total Short-Term Obligation: (Cost: $94,733)				94,733
Total Investments: 102.7% (Cost: $1,622,045)(f)				2,100,743
Obligation to Return Collateral for Securities Loaned: (3.0)%				(61,634	)
Cash and Other Assets Less Liabilities: 0.3%				5,958
Total Net Assets: 100.0%			$	2,045,067

ADR = American Depositary Receipts

See accompanying notes to financial statements.

65

Columbia Acorn Select

Statement of Investments (Unaudited), 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 June 30, 2011. The total market value of Fund securities on loan at June 30, 2011 was $59,666.

(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 six months ended June 30, 2011, are as follows:

Affiliates	Balance of Shares Held 12/31/10		Purchases/ Additions		Sales/ Reductions		Balance of Shares Held 6/30/11		Value		Dividend
Canacol Energy		36,240,000		-		1,710,000		34,530,000	$	37,863	$	-
Canadian Overseas Petroleum+		16,800,000		36,000,000		16,800,000		36,000,000		12,731		-
Canadian Solar		3,200,000		100,000		-		3,300,000		37,950		-
Eacom Timber		38,000,000		-		-		38,000,000		11,970		-
Globalstar		15,000,000		-		-		15,000,000		18,450		-
IFM Investments (Century 21 China RE) - ADR		2,300,000		-		-		2,300,000		3,381		-
Petrodorado+		45,544,000		6,456,000		-		52,000,000		12,763		-
Real Goods Solar		1,500,000		100,000		-		1,600,000		4,736		-
Sanmina-SCI		7,100,000		-		150,000		6,950,000		71,793		-
ShaMaran Petroleum		35,950,000		2,843,100		449,200		38,343,900		30,216		-
Synthesis Energy Systems		4,500,000		-		649,628		3,850,372		7,200		-
Tuscany International Drilling*+		13,224,000		-		1,578,300		11,645,700		10,412		-
VisionChina Media - ADR*		3,675,000		-		101,600		3,573,400		10,113		-
WNS - ADR		4,200,000		27,186		-		4,227,186		37,580		-
Total of Affiliated Transactions		227,233,000		45,526,286		21,438,728		251,320,558	$	307,158	$	-

*  At June 30, 2011, the Fund owned less than five percent of the company's outstanding voting shares.

+  Includes the effects of a corporate action.

  The aggregate cost and value of these affiliated companies at June 30, 2011, were $368,957 and $286,633, respectively. Investments in affiliated companies represented 14.0% of the Fund's total net assets at June 30, 2011.

(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 June 30, 2011, the value of these securities amounted to $54,784, which represented 2.68% of total net assets.

  Additional information on these securities is as follows:

Security	Acquisition Dates	Shares		Cost		Value
Union Agriculture Group	12/08/10		9,090,909	$	20,000	$	20,000
Eacom Timber	3/17/10		38,000,000		18,812		11,970
Canadian Overseas Petroleum	11/24/10		24,000,000		10,260		11,096
Canacol Energy	4/15/10		4,000,000		2,963		4,308
Petromanas	5/20/10		13,125,000		4,561		3,868
Petrodorado - Warrants	11/20/09		17,144,000		2,118		1,740
Canadian Overseas Petroleum - Warrants	11/24/10		12,000,000		1,502		1,635
Petromanas - Warrants	5/20/10		6,562,500		380		167
				$	60,596	$	54,784

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

(f)  At June 30, 2011, for federal income tax purposes, the cost of investments was $1,622,045 and net unrealized appreciation was $478,698, consisting of gross unrealized appreciation of $688,871 and gross unrealized depreciation of $210,173.

  Various inputs are used in determining the value of the Fund's investments, following the input prioritization hierarchy established by GAAP. These inputs are summarized in the three broad levels listed below:

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

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

•  Level 3 – prices determined using significant unobservable inputs where quoted prices or observable inputs are unavailable or less reliable (including management's own assumptions about the factors market participants would use in pricing an investment)

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

See accompanying notes to financial statements.

66

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

  Examples of the types of securities in which the Fund 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 Valuation Committee of the Fund's Board of Trustees that rely on significant observable inputs are also included in Level 2. Typical Level 3 securities include any security fair valued by the Valuation Committee that relies on significant unobservable inputs.

The following table summarizes the inputs used, as of June 30, 2011, 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	$	462,738	$	32,405	$	—	$	495,143
Industrial Goods & Services		389,200		—		—		389,200
Information		312,579		—		—		312,579
Energy & Minerals		245,650		34,784		20,000		300,434
Finance		300,099		—		—		300,099
Other Industries		112,271		—		—		112,271
Health Care		34,650		—		—		34,650
Total Equities		1,857,187		67,189		20,000		1,944,376
Total Securities Lending Collateral		61,634		—		—		61,634
Total Short-Term Obligation		—		94,733		—		94,733
Total Investments	$	1,918,821	$	161,922	$	20,000	$	2,100,743

  The Fund's assets assigned to the Level 2 input category are generally valued using a market approach, in which a security's value is determined through its correlation to prices and information from observable market transactions for similar or identical assets. Foreign equities are generally valued at the last sales price on the foreign exchange or market on which they trade. The Fund may use a systematic fair valuation model provided by an independent third party to value securities principally traded in foreign markets in order to adjust for possible stale pricing that may occur between the close of the foreign exchanges and the time for valuation. These models take into account available market data including intraday index, ADR, and ETF movements. Securities acquired via private placement that have a holding period or an extended settlement period are valued at a discount to the same shares that are trading freely on the market. These discounts are determined by the adviser's experience with similar securities or situations. Factors may include, but are not limited to, trade volume, shares outstanding and stock price. Warrants which do not trade are valued as a percentage of the actively trading common stocks using a model based on Black Scholes.

  Certain short-term obligations may be valued using amortized cost, an income approach which converts future cash flows to a present value based upon the discount or premium at purchase.

  The Fund's assets assigned to the Level 3 input category are valued at fair value as determined in good faith under consistently applied procedures established by and under the general supervision of the Board of Trustees. To determine fair value, management will utilize the valuation technique that they deem the most appropriate in the circumstances. Securities acquired via private placement that are not yet trading are valued using a market approach for which management has determined that the original transaction price is the best representation of fair value. The original cost may be adjusted for the market movement in an index, ETF or similar security during the period it does not trade.

  There were no significant transfers of financial assets between levels 1 and 2 during the period.

  The following table reconciles asset balances for the six months ending June 30, 2011, in which significant unobservable inputs (Level 3) were used in determining value:

Investments in Securities	Balance as of December 31, 2010		Realized Gain/(Loss)		Change in Unrealized Appreciation (Depreciation)		Purchases		Sales		Transfers into Level 3		Transfers out of Level 3		Balance as of June 30, 2011
Equities
Energy & Minerals	$	20,000	$	-	$	-	$	-	$	-	$	-	$	-	$	20,000
	$	20,000	$	-	$	-	$	-	$	-	$	-	$	-	$	20,000

  The information in the above reconciliation table represents fiscal year to date activity for any securities identified as using Level 3 inputs at either the beginning or the end of the current fiscal period.

  The change in unrealized appreciation (depreciation) attributed to securities owned at June 30, 2011, which were valued using significant unobservable inputs (Level 3) amounted to $0. This amount is included in net change in unrealized appreciation (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.

67

Columbia Thermostat Fund

Statement of Investments (Unaudited), June 30, 2011

Number of Shares			Value (000)
		> Affiliated Stock Funds: 60.6%
	1,221	Columbia Dividend Income Fund, Class I	$	16,734
	394	Columbia Acorn International, Class I		16,221
	577	Columbia Marsico Growth Fund, Class I		12,678
	396	Columbia Acorn Fund, Class I		12,664
	301	Columbia Acorn Select, Class I		8,493
	652	Columbia Large Cap Enhanced Core Fund, Class I		8,439
	555	Columbia Contrarian Core Fund, Class I		8,392
Total Stock Funds: (Cost: $65,310)				83,621
		> Affiliated Bond Funds: 39.2%
	2,969	Columbia Intermediate Bond Fund, Class I		27,015
	1,450	Columbia U.S. Treasury Index Fund, Class I		16,237
	1,120	Columbia Income Opportunities Fund, Class I		10,804
Total Bond Funds: (Cost: $53,022)				54,056

Principal Amount (000)			Value (000)
Short-Term Obligation: 0.4%
		> Repurchase Agreement: 0.4%
$	478	Repurchase Agreement with Fixed Income Clearing Corp., dated 6/30/11, due 7/01/11 at 0.01%, collateralized by a U.S. Government Agency obligation maturing 8/18/17, market value $490 (repurchase proceeds $478)	$	478
Total Short-Term Obligation: (Cost: $478)				478
Total Investments: 100.2% (Cost: $118,810)(a)				138,155
Cash and Other Assets Less Liabilities: (0.2)%				(216	)
Total Net Assets: 100.0%			$	137,939

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

(a)  At June 30, 2011, for federal income tax purposes, the cost of investments was $118,810 and net unrealized appreciation was $19,345, consisting of gross unrealized appreciation of $19,646 and gross unrealized depreciation of $301.

  Various inputs are used in determining the value of the Fund's investments, following the input prioritization hierarchy established by GAAP. These inputs are summarized in the three broad levels listed below:

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

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

•  Level 3 – prices determined using significant unobservable inputs where quoted prices or observable inputs are unavailable or less reliable (including management's own assumptions about the factors market participants would use in pricing an investment)

  The inputs or methodology 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 Fund 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 Valuation Committee of the Fund's Board of Trustees that rely on significant observable inputs are also included in Level 2. Typical Level 3 securities include any security fair valued by the Valuation Committee that relies on significant unobservable inputs.

The following table summarizes the inputs used, as of June 30, 2011, 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	$	83,621	$	-	$	-	$	83,621
Total Bond Funds		54,056		-		-		54,056
Total Short-Term Obligation		-		478		-		478
Total Investments	$	137,677	$	478	$	-	$	138,155

  The Fund's assets assigned to the Level 2 category include certain short-term obligations generally valued using amortized cost, an income approach which converts future cash flows to a present value based upon the discount or premium at purchase.

  There were no significant transfers of financial assets between levels 1 and 2 during the period.

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

See accompanying notes to financial statements.

68

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69

Columbia Acorn Family of Funds

Statements of Assets and Liabilities (Unaudited)

June 30, 2011	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	$	9,331,368		$	4,336,507		$	1,239,910		$	282,220		$	1,158,355		$	—
Affiliated investments, at cost (See Note 4)		2,325,878			85,252			4,479			—			368,957			118,332
Repurchase agreements, at cost		534,686			226,923			15,821			58,891			94,733			478
Unaffiliated investments, at value (including securities on loan: Columbia Acorn Fund $340,090; Columbia Acorn International $88,468; Columbia Acorn USA $12,520; Columbia Acorn International Select $—; Columbia Acorn Select $59,666; Columbia Thermostat Fund $—)	$	15,285,789		$	6,138,447		$	1,910,189		$	380,651		$	1,719,377		$	—
Affiliated investments, at value (See Note 4)		3,845,216			104,674			3,798			—			286,633			137,677
Repurchase agreements, at value		534,686			226,923			15,821			58,891			94,733			478
Cash		2,224			—	*		—			1			1			1
Foreign currency (cost: Columbia Acorn Fund $2,127; Columbia Acorn International $38,419; Columbia Acorn International Select $525; Columbia Acorn Select $151)		2,150			38,737			—			526			151			—
Net unrealized appreciation on forward foreign currency exchange contracts		—			3,057			—			—			—			—
Receivable for:
Investments sold		46,268			14,133			4,998			—			18,286			174
Fund shares sold		16,431			19,476			1,248			407			1,206			65
Dividends and interest		8,993			6,343			693			329			1,378			—
Securities lending income		200			105			15			8			55			—
Foreign tax reclaims		296			1,706			—			124			—			—
Expense reimbursement due from Adviser		—			—			—			—	*		—			27
Trustees' Deferred Compensation Investments		2,417			687			197			39			250			23
Other assets		147			48			24			3			10			17
Total Assets		19,744,817			6,554,336			1,936,983			440,979			2,122,080			138,462
Liabilities:
Collateral on securities loaned		352,904			90,621			12,944			—			61,634			—
Net unrealized depreciation on forward foreign currency exchange contracts		—			2,796			—			—			—			—
Payable for:
Investments purchased		77,052			9,632			5,767			2,829			8,297			—
Fund shares redeemed		45,467			4,970			3,949			258			4,551			335
Management fee		9,786			3,956			1,299			339			1,340			11
Administration fee		578			197			57			14			62			4
12b-1 Service & Distribution fees		1,591			281			76			26			205			43
Reports to shareholders		821			395			84			74			264			70
Deferred Trustees' fees		2,417			687			197			39			250			23
Transfer agent fees		2,066			354			236			38			356			24
Trustees' fees		18			—			1			—			2			—
Professional fee		140			63			21			22			20			13
Custody fees		75			509			3			32			25			—
Foreign capital gains tax		—			201			—			—			—			—
Other liabilities		43			14			4			9			7			—
Total Liabilities		492,958			114,676			24,638			3,680			77,013			523
Net Assets	$	19,251,859		$	6,439,660		$	1,912,345		$	437,299		$	2,045,067		$	137,939
Composition of Net Assets:
Paid in capital	$	11,501,455		$	4,977,351		$	1,263,898		$	345,003		$	1,567,317		$	143,450
Undistributed/(overdistributed) net investment income (Accumulated net investment loss)		(101,213	)		(102,703	)		(5,413	)		(4,301	)		(53,711	)		1,525
Accumulated net realized gain/(loss)		377,782			(256,826	)		(15,738	)		(1,843	)		52,764			(26,381	)
Net unrealized appreciation/(depreciation) on:
Investments		7,473,759			1,821,362			669,598			98,431			478,698			19,345
Foreign capital gains tax		—			(201	)		—			—			—			—
Foreign currency translations		76			677			—			9			(1	)		—
Net Assets	$	19,251,859		$	6,439,660		$	1,912,345		$	437,299		$	2,045,067		$	137,939
Net asset value per share – Class A (a)	$	30.95		$	41.02		$	30.01		$	28.69		$	27.50		$	12.98
(Net assets/shares)	($3,926,256/126,838)			($908,471/22,149)			($212,735/7,088)			($71,320/2,486)			($509,474/18,526)			($54,090/4,166)
Maximum offering price per share – Class A (b)	$	32.84		$	43.52		$	31.84		$	30.44		$	29.18		$	13.77
(Net asset value per share/front- end sales charge)	($30.95/0.9425)			($41.02/0.9425)			($30.01/0.9425)			($28.69/0.9425)			($27.50/0.9425)			($12.98/0.9425)
Net asset value and offering price per share – Class B (a)	$	28.62		$	39.97	(d)	$	27.79	(d)	$	27.42	(d)	$	25.70		$	13.04
(Net assets/shares)	($188,366/6,581)			($23,575/590)			($7,112/255)			($2,563/93)			($53,225/2,071)			($21,615/1,658)
Net asset value and offering price per share – Class C (a)	$	28.30		$	39.82		$	27.57	(d)	$	27.29		$	25.49	(d)	$	13.02
(Net assets/shares)	($876,147/30,954)			($100,222/2,517)			($36,348/1,319)			($11,463/420)			($87,862/3,446)			($22,788/1,750)
Net asset value and offering price per share – Class I	$	31.96	(d)	$	41.15	(d)	$	31.18	(d)	$	29.00		$	28.25	(d)
(Net assets/shares)	($12,665/396)			($27,769/675)			($3,211/103)			($3/0**)			($8,496/301)
Net asset value and offering price per share – Class Z (c)	$	31.95		$	41.13		$	31.17		$	28.98		$	28.25		$	12.86
(Net assets/shares)	($14,248,425/446,005)			($5,379,623/130,798)			($1,652,939/53,033)			($351,950/12,145)			($1,386,010/49,056)			($39,446/3,068)

(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.

(d)  Due to rounding of shares outstanding.

*  Rounds to less than $500.

**  Rounds to less than 500 shares.

See accompanying notes to financial statements.

70

Columbia Acorn Family of Funds

Statements of Operations (Unaudited)
For the Six Months Ended June 30, 2011

(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	$	62,270		$	84,948		$	4,453		$	5,929		$	6,882		$	—
Dividend income from affiliates (See Note 4)		5,944			2,397			—			—			—			—
Dividends from affiliated investment company shares (See Note 4)		—			—			—			—			—			2,023
Interest income		167			95			4			6			26			—	*
Securitites lending income, net		1,053			454			95			14			131			—
		69,434			87,894			4,552			5,949			7,039			2,023
Foreign taxes withheld		(1,493	)		(7,054	)		(8	)		(471	)		(88	)		—
Total Investment Income		67,941			80,840			4,544			5,478			6,951			2,023
Expenses:
Management fee		59,852			23,819			7,935			2,084			8,907			68
Administration fee		3,530			1,184			349			84			414			26
12b-1 Service and Distribution fees:
Class A		4,732			1,083			271			90			671			60
Class B		903			99			31			11			237			99
Class C		4,258			547			180			58			468			112
Transfer agent fees:
Class A		1,554			593			94			57			276			32
Class B		347			41			14			5			86			28
Class C		472			83			20			12			68			17
Class Z		2,623			1,225			415			57			445			9
Custody fees		649			2,120			28			118			156			—
Trustees' fees		538			176			51			15			66			5
Reports to shareholders		1,018			548			169			70			259			56
Professional fees		559			208			61			32			71			13
Chief compliance officer expenses (See Note 4)		258			79			25			7			34			2
Other expenses		359			168			76			59			97			41
Total expenses		81,652			31,973			9,719			2,759			12,255			568
Less custody fees paid indirectly		—	*		—	*		—	*		—	*		—	*		—
Less reimbursement of expenses by Investment Adviser		—			—			—			—	*		—			(129	)
Net Expenses		81,652			31,973			9,719			2,759			12,255			439
Net Investment Income/(Loss)		(13,711	)		48,867			(5,175	)		2,719			(5,304	)		1,584
Net Realized and Unrealized Gain (Loss) on Portfolio Positions:
Net realized gain/(loss) on:
Unaffiliated investments		381,947			133,208			13,002			34,920			175,643			3,561
Affiliated investments (See Note 4)		11,248			(2,643	)		—			—			(2,797	)		—
Foreign currency transactions and forward foreign currency exchange contracts		146			1,067			—			(52	)		(65	)		—
Distributions from affiliated investment company shares		—			—			—			—			—			156
Net realized gain		393,341			131,632			13,002			34,868			172,781			3,717
Net change in net unrealized appreciation/(depreciation) on:
Unaffiliated investments		507,051			14,580			154,928			(21,427	)		(79,517	)		—
Affiliated investments (See Note 4)		397,583			2,549			504			—			(89,482	)		552
Foreign currency translations and forward foreign currency exchange contracts		46			(11,766	)		—			(3	)		(2	)		—
Foreign capital gains tax		—			306			—			—			—			—
Net change in unrealized appreciation/ (depreciation)		904,680			5,669			155,432			(21,430	)		(169,001	)		552
Net realized and unrealized gain		1,298,021			137,301			168,434			13,438			3,780			4,269
Net Increase/(Decrease) in Net Assets resulting from Operations	$	1,284,310		$	186,168		$	163,259		$	16,157		$	(1,524	)	$	5,853

*  Rounds to less than $500.

See accompanying notes to financial statements.

71

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	(Unaudited) Six months ended June 30,			Year ended December 31,			(Unaudited) Six months ended June 30,			Year ended December 31,			(Unaudited) Six months ended June 30,			Year ended December 31,
(in thousands)	2011			2010 (a)(b)			2011			2010 (a)(b)			2011			2010 (a)(b)
Operations:
Net investment income/(loss)	$	(13,711	)	$	(7,374	)	$	48,867		$	45,340		$	(5,175	)	$	(5,972	)
Net realized gain/(loss) on investments, foreign currency transactions, forward foreign currency exchange contracts and foreign capital gains tax		382,093			971,334			134,275			276,374			13,002			96,553
Net realized gain/(loss) on affiliated investments and distributions from affiliated investment companies and affiliated investment company shares		11,248			139,546			(2,643	)		5,786			—			(1,208	)
Net change in net unrealized appreciation/(depreciation) on investments, foreign currency translations, forward foreign currency exchange contracts and foreign capital gains tax		507,097			1,864,571			3,120			752,452			154,928			224,623
Net change in net unrealized appreciation/(depreciation) on affiliated investment companies and affiliated investment company shares		397,583			758,959			2,549			6,050			504			4,434
Net Increase/(Decrease) from Operations		1,284,310			3,727,036			186,168			1,086,002			163,259			318,430
Distributions to Shareholders From:
Net investment income – Class A		(2,047	)		(2,387	)		(21,972	)		(12,578	)		—			—
Net realized gain – Class A		(38,150	)		(100,919	)		—			—			—			—
Net investment income – Class B		—			—			(600	)		(290	)		—			—
Net realized gain – Class B		(2,204	)		(9,116	)		—			—			—			—
Net investment income – Class C		—			—			(2,369	)		(714	)		—			—
Net realized gain – Class C		(9,366	)		(25,102	)		—			—			—			—
Net investment income – Class I		(34	)		—	*		(676	)		(9	)		—			—
Net realized gain – Class I		(119	)		—	*		—			—			—			—
Net investment income – Class Z		(36,823	)		(18,634	)		(131,455	)		(109,328	)		—			—
Net realized gain – Class Z		(134,735	)		(361,156	)		—			—			—			—
Total Distributions to Shareholders		(223,478	)		(517,314	)		(157,072	)		(122,919	)		—			—
Share Transactions:
Subscriptions – Class A		513,660			843,928			183,011			317,458			24,680			55,029
Distributions reinvested – Class A		36,444			94,158			18,983			10,862			—			—
Redemptions – Class A		(481,606	)		(866,166	)		(107,204	)		(221,501	)		(45,052	)		(59,786	)
Net Increase/(Decrease) – Class A		68,498			71,920			94,790			106,819			(20,372	)		(4,757	)
Subscriptions – Class B		278			989			58			35			4			2
Distributions reinvested – Class B		1,814			7,325			494			260			—			—
Redemptions – Class B		(114,111	)		(312,686	)		(6,359	)		(15,278	)		(2,795	)		(13,951	)
Net Decrease – Class B		(112,019	)		(304,372	)		(5,807	)		(14,983	)		(2,791	)		(13,949	)
Subscriptions – Class C		66,633			76,903			11,504			24,476			1,195			1,669
Distributions reinvested – Class C		7,134			19,273			1,844			590			—			—
Redemptions – Class C		(71,870	)		(145,469	)		(24,543	)		(17,799	)		(3,930	)		(4,671	)
Net Increase/(Decrease) – Class C		1,897			(49,293	)		(11,195	)		7,267			(2,735	)		(3,002	)
Subscriptions – Class I		4,307			13,063			8,133			66,675			10,803			28,852
Distributions reinvested – Class I		153			—			675			9			—			—
Redemptions – Class I		(4,183	)		(1,538	)		(48,107	)		(2,003	)		(38,271	)		(293	)
Net Increase/(Decrease) – Class I		277			11,525			(39,299	)		64,681			(27,468	)		28,559
Subscriptions – Class Z		1,182,084			2,077,687			589,377			1,216,447			234,528			260,284
Distributions reinvested – Class Z		145,609			324,149			91,324			76,344			—			—
Redemptions – Class Z		(1,194,031	)		(1,969,778	)		(433,689	)		(726,019	)		(130,622	)		(276,628	)
Net Increase/(Decrease) – Class Z		133,662			432,058			247,012			566,772			103,906			(16,344	)
Net Increase/(Decrease) from Share Transactions		92,315			161,838			285,501			730,556			50,540			(9,493	)
Redemption Fees		—			—			—			239			—			—
Increase from regulatory settlements (See Note 9)		—			1			—			447			—			—
Total Increase/(Decrease) in Net Assets		1,153,147			3,371,561			314,597			1,694,325			213,799			308,937
Net Assets:
Beginning of period		18,098,712			14,727,151			6,125,063			4,430,738			1,698,546			1,389,609
End of period	$	19,251,859		$	18,098,712		$	6,439,660		$	6,125,063		$	1,912,345		$	1,698,546
Undistributed/(Overdistributed) Net Investment Income or (Accumulated Net Investment Loss)	$	(101,213	)	$	(48,598	)	$	(102,703	)	$	5,502		$	(5,413	)	$	(238	)

(a)  Class I Shares commenced operations on September 27, 2010.

(b)  Class I Shares reflect activity for the period September 27, 2010 through December 31, 2010.

*  Rounds to less than $500.

See accompanying notes to financial statements.

72

	Columbia Acorn International Select						Columbia Acorn Select						Columbia Thermostat Fund
Increase (Decrease) in Net Assets	(Unaudited) Six months ended June 30,			Year ended December 31,			(Unaudited) Six months ended June 30,			Year ended December 31,			(Unaudited) Six months ended June 30,			Year ended December 31,
(in thousands)	2011			2010 (a)(b)			2011			2010 (a)(b)			2011			2010
Operations:
Net investment income/(loss)	$	2,719		$	2,667		$	(5,304	)	$	(11,783	)	$	1,584		$	1,806
Net realized gain/(loss) on investments, foreign currency transactions, forward foreign currency exchange contracts and foreign capital gains tax		34,868			42,527			175,578			59,672			—			—
Net realized gain/(loss) on affiliated investments and distributions from affiliated investment companies and affiliated investment company shares		—			—			(2,797	)		(38,281	)		3,717			(1,976	)
Net change in net unrealized appreciation/(depreciation) on investments, foreign currency translations, forward foreign currency exchange contracts and foreign capital gains tax		(21,430	)		38,193			(79,519	)		283,123			—			—
Net change in net unrealized appreciation/(depreciation) on affiliated investment companies and affiliated investment company shares		—			—			(89,482	)		123,090			552			19,741
Net Increase/(Decrease) from Operations		16,157			83,387			(1,524	)		415,821			5,853			19,571
Distributions to Shareholders From:
Net investment income – Class A		(770	)		(776	)		(7,162	)		—			(625	)		(678	)
Net realized gain – Class A		—			—			—			—			—			—
Net investment income – Class B		(16	)		(25	)		(500	)		—			(249	)		(239	)
Net realized gain – Class B		—			—			—			—			—			—
Net investment income – Class C		(50	)		(65	)		(672	)		—			(191	)		(124	)
Net realized gain – Class C		—			—			—			—			—			—
Net investment income – Class I		—	*		—			(141	)		—			—			—
Net realized gain – Class I		—			—			—			—			—			—
Net investment income – Class Z		(5,052	)		(5,241	)		(22,715	)		—			(473	)		(625	)
Net realized gain – Class Z		—			—			—			—			—			—
Total Distributions to Shareholders		(5,888	)		(6,107	)		(31,190	)		—			(1,538	)		(1,666	)
Share Transactions:
Subscriptions – Class A		10,119			18,214			40,885			115,498			12,599			8,937
Distributions reinvested – Class A		667			675			6,307			—			501			609
Redemptions – Class A		(12,913	)		(23,778	)		(85,032	)		(187,411	)		(5,038	)		(13,847	)
Net Increase/(Decrease) – Class A		(2,127	)		(4,889	)		(37,840	)		(71,913	)		8,062			(4,301	)
Subscriptions – Class B		2			—	*		69			34			45			4
Distributions reinvested – Class B		13			22			391			—			181			218
Redemptions – Class B		(557	)		(1,418	)		(18,583	)		(30,406	)		(8,198	)		(8,516	)
Net Decrease – Class B		(542	)		(1,396	)		(18,123	)		(30,372	)		(7,972	)		(8,294	)
Subscriptions – Class C		636			1,883			2,746			6,743			2,665			3,195
Distributions reinvested – Class C		40			55			495			—			149			109
Redemptions – Class C		(1,405	)		(3,121	)		(12,612	)		(19,302	)		(2,602	)		(5,530	)
Net Increase/(Decrease) – Class C		(729	)		(1,183	)		(9,371	)		(12,559	)		212			(2,226	)
Subscriptions – Class I		—			3			3,155			8,577			—			—
Distributions reinvested – Class I		—			—			141			—			—			—
Redemptions – Class I		—			—			(2,611	)		(931	)		—			—
Net Increase/(Decrease) – Class I		—			3			685			7,646			—			—
Subscriptions – Class Z		28,129			67,172			108,942			358,116			5,619			7,895
Distributions reinvested – Class Z		1,771			1,451			17,488			—			410			560
Redemptions – Class Z		(52,139	)		(96,502	)		(266,855	)		(328,729	)		(3,982	)		(18,853	)
Net Increase/(Decrease) – Class Z		(22,239	)		(27,879	)		(140,425	)		29,387			2,047			(10,398	)
Net Increase/(Decrease) from Share Transactions		(25,637	)		(35,344	)		(205,074	)		(77,811	)		2,349			(25,219	)
Redemption Fees		—			10			—			—			—			—
Increase from regulatory settlements (See Note 9)		—			46			—			—			—			—
Total Increase/(Decrease) in Net Assets		(15,368	)		41,992			(237,788	)		338,010			6,664			(7,314	)
Net Assets:
Beginning of period		452,667			410,675			2,282,855			1,944,845			131,275			138,589
End of period	$	437,299		$	452,667		$	2,045,067		$	2,282,855		$	137,939		$	131,275
Undistributed/(Overdistributed) Net Investment Income or (Accumulated Net Investment Loss)	$	(4,301	)	$	(1,132	)	$	(53,711	)	$	(17,217	)	$	1,525		$	1,479

See accompanying notes to financial statements.

73

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:	(Unaudited) Six months ended June 30,			Year ended December 31,			(Unaudited) Six months ended June 30,			Year ended December 31,			(Unaudited) Six months ended June 30,			Year ended December 31,
(in thousands)	2011			2010 (a)(b)			2011			2010 (a)(b)			2011			2010 (a)(b)
Subscriptions – Class A		17,024			32,735			4,451			8,744			852			2,334
Shares issued in reinvestment – Class A		1,237			3,306			463			325			—			—
Less shares redeemed – Class A		(15,908	)		(34,053	)		(2,601	)		(6,188	)		(1,539	)		(2,521	)
Net Increase/(Decrease) – Class A		2,353			1,988			2,313			2,881			(687	)		(187	)
Subscriptions – Class B		10			38			2			1			—	*		—	*
Shares issued in reinvestment – Class B		66			276			12			9			—			—
Less shares redeemed – Class B		(4,094	)		(13,126	)		(159	)		(444	)		(105	)		(636	)
Net Decrease – Class B		(4,018	)		(12,812	)		(145	)		(434	)		(105	)		(636	)
Subscriptions – Class C		2,406			3,197			288			700			45			76
Shares issued in reinvestment – Class C		265			733			46			19			—			—
Less shares redeemed – Class C		(2,599	)		(6,190	)		(605	)		(519	)		(148	)		(214	)
Net Increase/(Decrease) – Class C		72			(2,260	)		(271	)		200			(103	)		(138	)
Subscriptions – Class I		138			436			196			1,677			361			1,025
Shares issued in reinvestment – Class I		5			—			17			—	*		—			—
Less shares redeemed – Class I		(132	)		(51	)		(1,165	)		(50	)		(1,273	)		(10	)
Net Increase/(Decrease) – Class I		11			385			(952	)		1,627			(912	)		1,015
Subscriptions – Class Z		37,835			78,950			14,274			33,971			7,994			10,643
Shares issued in reinvestment – Class Z		4,790			11,048			2,222			2,239			—			—
Less shares redeemed – Class Z		(38,207	)		(74,926	)		(10,531	)		(20,195	)		(4,340	)		(11,173	)
Net Increase/(Decrease) – Class Z		4,418			15,072			5,965			16,015			3,654			(530	)
Net Increase/(Decrease) in Shares of Beneficial Interest		2,836			2,373			6,910			20,289			1,847			(476	)

(a)  Class I Shares commenced operations on September 27, 2010.

(b)  Class I Shares reflect activity for the period September 27, 2010 through December 31, 2010.

*  Rounds to less than 500.

See accompanying notes to financial statements.

74

	Columbia Acorn International Select						Columbia Acorn Select						Columbia Thermostat Fund
Changes in Shares of Beneficial Interest:	(Unaudited) Six months ended June 30,			Year ended December 31,			(Unaudited) Six months ended June 30,			Year ended December 31,			(Unaudited) Six months ended June 30,			Year ended December 31,
(in thousands)	2011			2010 (a)(b)			2011			2010 (a)(b)			2011			2010
Subscriptions – Class A		355			746			1,468			4,815			977			765
Shares issued in reinvestment – Class A		23			31			242			—			39			56
Less shares redeemed – Class A		(451	)		(982	)		(3,056	)		(7,851	)		(391	)		(1,223	)
Net Increase/(Decrease) – Class A		(73	)		(205	)		(1,346	)		(3,036	)		625			(402	)
Subscriptions – Class B		—	*		—	*		3			2			4			—	*
Shares issued in reinvestment – Class B		—	*		1			16			—			14			21
Less shares redeemed – Class B		(20	)		(62	)		(719	)		(1,342	)		(634	)		(744	)
Net Decrease – Class B		(20	)		(61	)		(700	)		(1,340	)		(616	)		(723	)
Subscriptions – Class C		23			83			106			299			207			275
Shares issued in reinvestment – Class C		1			2			21			—			12			10
Less shares redeemed – Class C		(51	)		(138	)		(492	)		(870	)		(202	)		(485	)
Net Increase/(Decrease) – Class C		(27	)		(53	)		(365	)		(571	)		17			(200	)
Subscriptions – Class I		—			—	*		111			305			—			—
Shares issued in reinvestment – Class I		—			—			5			—			—			—
Less shares redeemed – Class I		—			—			(88	)		(32	)		—			—
Net Increase/(Decrease) – Class I		—			—	*		28			273			—			—
Subscriptions – Class Z		973			2,699			3,786			14,221			443			697
Shares issued in reinvestment – Class Z		61			66			654			—			32			51
Less shares redeemed – Class Z		(1,812	)		(3,845	)		(9,298	)		(13,400	)		(311	)		(1,710	)
Net Increase/(Decrease) – Class Z		(778	)		(1,080	)		(4,858	)		821			164			(962	)
Net Increase/(Decrease) in Shares of Beneficial Interest		(898	)		(1,399	)		(7,241	)		(3,853	)		190			(2,287	)

See accompanying notes to financial statements.

75

Columbia Acorn Family of Funds

Financial Highlights

Columbia Acorn Fund

Class Z Shares	(Unaudited) Six months ended June 30,			Year ended December 31,
Selected data for a share outstanding throughout each period	2011			2010			2009			2008			2007			2006
Net Asset Value, Beginning of Period	$	30.19		$	24.68		$	17.71		$	29.61		$	29.71		$	28.17
Income from Investment Operations
Net investment income/(loss) (a)		(0.00	)(b)		0.02			0.04			0.06			0.15	(c)		0.13
Net realized and unrealized gain/(loss)		2.15			6.37			6.98			(11.29	)		2.17			3.92
Total from Investment Operations		2.15			6.39			7.02			(11.23	)		2.32			4.05
Less Distributions to Shareholders
From net investment income		(0.09	)		(0.04	)		(0.05	)		(0.01	)		(0.12	)		(0.13	)
From net realized gains		(0.30	)		(0.84	)		—			(0.66	)		(2.30	)		(2.38	)
Total Distributions to Shareholders		(0.39	)		(0.88	)		(0.05	)		(0.67	)		(2.42	)		(2.51	)
Increase from regulatory settlements		—			0.00	(b)		0.00	(b)		—			—			—
Net Asset Value, End of Period	$	31.95		$	30.19		$	24.68		$	17.71		$	29.61		$	29.71
Total Return (d)		7.18	%(e)		26.00	%		39.65	%		(38.55	)%		7.69	%(f)(g)		14.45	%(f)
Ratios to Average Net Assets/Supplemental Data
Net expenses (h)		0.75	%(i)		0.76	%		0.77	%		0.76	%		0.74	%		0.74	%
Net investment income/(loss) (h)		(0.03	)%(i)		0.09	%		0.18	%		0.26	%		0.46	%		0.45	%
Waiver/Reimbursement		—			—			—			—			0.00	%(j)		0.01	%
Portfolio turnover rate		8	%(e)		28	%		27	%		21	%		20	%		22	%
Net assets at end of period (in millions)	$	14,248		$	13,330		$	10,527		$	7,446		$	13,038		$	12,128

(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 $0.03 per share.

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

(e)  Not annualized.

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

(g)  Total return includes a voluntary reimbursement by the Adviser 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.

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

(i)  Annualized.

(j)  Rounds to less than 0.01%.

Columbia Acorn International

Class Z Shares	(Unaudited) Six months ended June 30,			Year ended December 31,
Selected data for a share outstanding throughout each period	2011			2010			2009			2008			2007			2006
Net Asset Value, Beginning of Period	$	40.92		$	34.26		$	23.13		$	43.60		$	40.31		$	33.44
Income from Investment Operations
Net investment income (a)		0.33			0.35			0.34			0.60			0.43			0.35
Net realized and unrealized gain/(loss)		0.90			7.23			11.31			(20.26	)		6.56			10.94
Total from Investment Operations		1.23			7.58			11.65			(19.66	)		6.99			11.29
Less Distributions to Shareholders
From net investment income		(1.02	)		(0.92	)		(0.53	)		(0.21	)		(0.34	)		(0.51	)
From net realized gains		—			—			—			(0.60	)		(3.36	)		(3.91	)
Total Distributions to Shareholders		(1.02	)		(0.92	)		(0.53	)		(0.81	)		(3.70	)		(4.42	)
Redemption Fees
Redemption fees added to paid in capital		—			0.00	(a)(b)		0.00	(a)(b)		0.00	(a)(b)		0.00	(a)(b)		0.00	(a)(b)
Increase from regulatory settlements		—			0.00	(b)		0.01			—			—			—
Net Asset Value, End of Period	$	41.13		$	40.92		$	34.26		$	23.13		$	43.60		$	40.31
Total Return (c)		3.02	%(d)		22.70	%		50.97	%		(45.89	)%		17.28	%(e)		34.53	%(e)
Ratios to Average Net Assets/Supplemental Data
Net expenses (f)		0.95	%(g)		0.97	%		0.99	%		0.96	%		0.91	%		0.94	%
Net investment income (f)		1.63	%(g)		0.99	%		1.23	%		1.72	%		0.96	%		0.92	%
Waiver/Reimbursement		—			—			—			—			0.00	%(h)		0.01	%
Portfolio turnover rate		12	%(d)		25	%		31	%		38	%		28	%		31	%
Net assets at end of period (in millions)	$	5,380		$	5,108		$	3,728		$	2,372		$	4,918		$	3,836

(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)  Not annualized.

(e)  Had the Adviser 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)  Annualized.

(h)  Rounds to less than 0.01%.

See accompanying notes to financial statements.

76

Columbia Acorn USA

Class Z Shares	(Unaudited) Six months ended June 30,			Year ended December 31,
Selected data for a share outstanding throughout each period	2011			2010			2009			2008			2007			2006
Net Asset Value, Beginning of Period	$	28.56		$	23.19		$	16.39		$	27.97		$	28.66		$	27.03
Income from Investment Operations
Net investment loss (a)		(0.07	)		(0.08	)		(0.07	)		(0.07	)		(0.01	)(b)		(0.02	)
Net realized and unrealized gain/(loss)		2.68			5.45			6.87			(10.55	)		1.03			2.26
Total from Investment Operations		2.61			5.37			6.80			(10.62	)		1.02			2.24
Less Distributions to Shareholders
From net realized gains		—			—			—			(0.96	)		(1.71	)		(0.61	)
Increase from regulatory settlements		—			—			0.00	(c)		—			—			—
Net Asset Value, End of Period	$	31.17		$	28.56		$	23.19		$	16.39		$	27.97		$	28.66
Total Return (d)		9.14	%(e)		23.16	%		41.49	%		(39.22	)%		3.46	%(f)(g)		8.28	%(f)
Ratios to Average Net Assets/Supplemental Data
Net expenses (h)		0.99	%(i)		1.01	%		1.03	%		1.01	%		0.98	%		0.98	%
Net investment loss (h)		(0.50	)%(i)		(0.34	)%		(0.36	)%		(0.32	)%		(0.03	)%		(0.07	)%
Waiver/Reimbursement		—			—			—			—			0.00	%(j)		0.01	%
Portfolio turnover rate		9	%(e)		32	%		28	%		23	%		21	%		13	%
Net assets at end of period (in millions)	$	1,653		$	1,410		$	1,158		$	758		$	1,214		$	1,214

(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)  Not annualized.

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

(g)  Total return includes a voluntary reimbursement by the Adviser 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.

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

(i)  Annualized.

(j)  Rounds to less than 0.01%.

Columbia Acorn International Select

Class Z Shares	(Unaudited) Six months ended June 30,			Year ended December 31,
Selected data for a share outstanding throughout each period	2011			2010			2009			2008			2007			2006
Net Asset Value, Beginning of Period	$	28.33		$	23.64		$	18.19		$	32.02		$	27.97		$	20.57
Income from Investment Operations
Net investment income (a)		0.19	(b)		0.18			0.17			0.28			0.14	(c)		0.10
Net realized and unrealized gain/(loss)		0.87			4.89			5.50			(13.53	)		5.96			7.35
Total from Investment Operations		1.06			5.07			5.67			(13.25	)		6.10			7.45
Less Distributions to Shareholders
From net investment income		(0.41	)		(0.38	)		(0.24	)		(0.04	)		(0.28	)		(0.05	)
From net realized gains		—			—			—			(0.54	)		(1.77	)		—
Total Distributions to Shareholders		(0.41	)		(0.38	)		(0.24	)		(0.58	)		(2.05	)		(0.05	)
Redemption Fees
Redemption fees added to paid in capital		—			0.00	(a)(d)		0.00	(a)(d)		0.00	(a)(d)		0.00	(a)(d)		0.00	(a)(d)
Increase from regulatory settlements		—			0.00	(d)		0.02			—			—			—
Net Asset Value, End of Period	$	28.98		$	28.33		$	23.64		$	18.19		$	32.02		$	27.97
Total Return (e)		3.74	%(f)		21.89	%		31.52	%		(42.10	)%		21.86	%(g)		36.27	%(g)
Ratios to Average Net Assets/Supplemental Data
Net expenses (h)		1.15	%(i)		1.16	%		1.20	%		1.21	%		1.18	%		1.27	%
Net investment income (h)		1.33	%(i)		0.75	%		0.84	%		1.09	%		0.44	%		0.44	%
Waiver/Reimbursement		—			—			—			—			0.00	%(j)		0.01	%
Portfolio turnover rate		21	%(f)		42	%		56	%		68	%		57	%		47	%
Net assets at end of period (in millions)	$	352		$	366		$	331		$	186		$	204		$	129

(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 $0.04 per share.

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

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

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

(f)  Not annualized.

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

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

(i)  Annualized.

(j)  Rounds to less than 0.01%.

See accompanying notes to financial statements.

77

Columbia Acorn Family of Funds

Financial Highlights, continued

Columbia Acorn Select

Class Z Shares	(Unaudited) Six months ended June 30,			Year ended December 31,
Selected data for a share outstanding throughout each period	2011			2010			2009			2008			2007			2006
Net Asset Value, Beginning of Period	$	28.73		$	23.38		$	14.07		$	28.41		$	26.59		$	22.77
Income from Investment Operations
Net investment loss (a)		(0.05	)		(0.10	)		(0.08	)		(0.12	)		(0.07	)		(0.06	)
Net realized and unrealized gain/(loss)		0.03			5.45			9.39			(13.53	)		2.53			4.51
Total from Investment Operations		(0.02	)		5.35			9.31			(13.65	)		2.46			4.45
Less Distributions to Shareholders
From net investment income		(0.46	)		—			—			—			—			(0.04	)
From net realized gains		—			—			—			(0.69	)		(0.64	)		(0.59	)
Total Distributions to Shareholders		(0.46	)		—			—			(0.69	)		(0.64	)		(0.63	)
Net Asset Value, End of Period	$	28.25		$	28.73		$	23.38		$	14.07		$	28.41		$	26.59
Total Return (b)		0.02	%(c)		22.88	%		66.17	%		(49.18	)%(d)		9.20	%(e)		19.68	%(e)
Ratios to Average Net Assets/Supplemental Data
Net expenses (f)		0.97	%(g)		0.97	%		0.99	%		0.95	%		0.91	%		0.96	%
Net investment loss (f)		(0.34	)%(g)		(0.41	)%		(0.47	)%		(0.51	)%		(0.24	)%		(0.26	)%
Waiver/Reimbursement		—			—			—			—			0.00	%(h)		0.02
Portfolio turnover rate		13	%(c)		28	%		19	%		28	%		14	%		21	%
Net assets at end of period (in millions)	$	1,386		$	1,549		$	1,241		$	780		$	1,571		$	909

(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)  Not annualized.

(d)  Total return includes a voluntary reimbursement by the Adviser 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.

(e)  Had the Adviser 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)  Annualized.

(h)  Rounds to less than 0.01%.

Columbia Thermostat Fund

Class Z Shares	(Unaudited) Six months ended June 30,			Year ended December 31,
Selected data for a share outstanding throughout each period	2011			2010			2009			2008			2007			2006
Net Asset Value, Beginning of Period	$	12.44		$	10.80		$	8.19		$	12.26		$	12.57		$	12.50
Income from Investment Operations
Net investment income (a)		0.17			0.21			0.13			0.24			0.52			0.49
Net realized and unrealized gain/(loss)		0.41			1.66			2.51			(3.96	)		0.53			0.84
Total from Investment Operations		0.58			1.87			2.64			(3.72	)		1.05			1.33
Less Distributions to Shareholders
From net investment income		(0.16	)		(0.23	)		(0.03	)		(0.28	)		(0.57	)		(0.54	)
From net realized gains		—			—			—			(0.07	)		(0.79	)		(0.72	)
Total Distributions to Shareholders		(0.16	)		(0.23	)		(0.03	)		(0.35	)		(1.36	)		(1.26	)
Net Asset Value, End of Period	$	12.86		$	12.44		$	10.80		$	8.19		$	12.26		$	12.57
Total Return (b)(c)		4.66	%(d)		17.58	%		32.29	%		(30.53	)%		8.49	%		10.86	%
Ratios to Average Net Assets/Supplemental Data
Net expenses (e)(f)		0.25	%(g)		0.25	%		0.25	%		0.25	%		0.25	%		0.25	%
Net investment income (f)		2.75	%(g)		1.87	%		1.48	%		2.23	%		4.05	%		3.84	%
Waiver/Reimbursement		0.11	%(g)		0.12	%		0.14	%		0.08	%		0.15	%		0.13	%
Portfolio turnover rate		36	%(d)		118	%		17	%		130	%		128	%		66	%
Net assets at end of period (in millions)	$	39		$	36		$	42		$	35		$	36		$	31

(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 Adviser and/or Transfer Agent not waived fees and/or reimbursed a portion of expenses, total return would have been reduced.

(d)  Not annualized.

(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%.

(g)  Annualized.

See accompanying notes to financial statements.

78

Columbia Acorn Family of Funds

Notes to Financial Statements (Unaudited)

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 (S&P) 500 Index in relation to predetermined ranges set by Columbia Wanger Asset Management, LLC (the Adviser). 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 five classes of shares – Class A, Class B, Class C, Class I and Class Z – except Columbia Thermostat Fund, which does not have Class I shares. 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 I shares are offered continuously at net asset value. There are certain restrictions on the purchase of Class I shares.

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.

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

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.

>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 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 their 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.

79

Columbia Acorn Family of Funds

Notes to Financial Statements (Unaudited), continued

>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.

A Fund may use forward foreign currency exchange contracts to buy or sell a foreign currency when the Adviser 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, except Columbia Thermostat 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 Adviser 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 as of June 30, 2011 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

80

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 daily 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.

>Federal income taxes

It is each Fund's policy to comply with the provisions of the Internal Revenue Code available to regulated investment companies and, in the manner provided therein, distribute substantially 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 remote.

3.  Federal Tax Information

The tax character of distributions paid during the year ended December 31, 2010 was as follows:

	Ordinary Income*		Long-Term Capital Gains
(in thousands)
Columbia Acorn Fund	$	21,020	$	496,293
Columbia Acorn International		122,919		—
Columbia Acorn USA		—		—
Columbia Acorn International Select		6,107		—
Columbia Acorn Select		—		—
Columbia Thermostat Fund		1,666		—

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

The following capital loss carryforwards, determined as of December 31, 2010, may be available to reduce taxable

81

Columbia Acorn Family of Funds

Notes to Financial Statements (Unaudited), continued

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

	Year of Expiration
	2011- 2015		2016		2017		2018		Total
(in thousands)
Columbia Acorn International	$	—	$	—	$	386,385	$	—	$	386,385
Columbia Acorn USA		—		—		28,408		—		28,408
Columbia Acorn International Select		—		—		36,610		—		36,610
Columbia Acorn Select		—		3,592		115,445		—		119,037
Columbia Thermostat Fund		—		5,193		21,738		2,954		29,885

Capital loss carryforwards that were utilized for the Funds during the year ended December 31, 2010 were as follows:

(in thousands)
Columbia Acorn Fund	$	409,911
Columbia Acorn International		238,546
Columbia Acorn USA		85,334
Columbia Acorn International Select		40,289
Columbia Acorn Select		8,679

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 years remain subject to examination by the Internal Revenue Service.

4.  Transactions with Affiliates

Columbia Wanger Asset Management, LLC (CWAM) is a wholly owned subsidiary of Columbia Management, which in turn is a wholly owned subsidiary of Ameriprise Financial, Inc. (Ameriprise Financial). CWAM furnishes continuing investment supervision to the Funds and is responsible for the overall management of the Funds' business affairs.

CWAM received a monthly advisory fee based on each Fund's average daily net assets at the following annual rates:

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	%

For the six months ended June 30, 2011, the Funds' annualized effective investment advisory fee rates were as follows:

Columbia Acorn Fund	0.64	%
Columbia Acorn International	0.76	%
Columbia Acorn USA	0.86	%
Columbia Acorn International Select	0.94	%
Columbia Acorn Select	0.81	%
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 custodial

82

charges relating to overdrafts, if any) after giving effect to any balance credits from the Funds' custodian, exceeding annually the average daily net assets of the Funds as follows:

Fund	Class Z
Columbia Acorn International Select		1.45	%
Columbia Acorn Select		1.35	%

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, 2012. There is no guarantee that this arrangement will continue thereafter.

Expenses reimbursed by CWAM to Columbia Acorn International Select and Columbia Thermostat Fund for the six months ended June 30, 2011, were $363 and $128,651, 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 six months ended June 30, 2011, the annualized effective administration fee rate was 0.04% of each Fund's average daily net assets. CWAM has delegated to Columbia Management responsibility to provide certain sub-administrative services to the Funds.

Columbia Management Investment Distributors, Inc., (CMID) a wholly owned subsidiary of Ameriprise Financial, is the distributor of the Funds.

Each Fund has adopted a Rule 12b-1 (distribution and service) plan which requires it to pay CMID 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. CMID receives no compensation with respect to Class Z shares.

Columbia Management Investment Services Corp. (CMIS), a wholly owned subsidiary of Ameriprise Financial, is the transfer agent of the Funds. For its services, each Fund pays CMIS a monthly fee at the annual rate of $17.00 per open account. CMIS also receives reimbursement from the Fund's for certain out-of-pocket expenses. The arrangement with BFDS has been continued by CMIS.

Class I shares do not pay transfer agent fees.

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 of 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, 2010, 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 32, 33, 44, 54 and 66, respectively.

During the six months ended June 30, 2011, the Funds engaged in purchase and sale transactions with funds that have a common investment adviser (or affiliated investment advisers), common directors/trustees, and/or common officers.

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Columbia Acorn Family of Funds

Notes to Financial Statements (Unaudited), continued

Those transactions complied with Rule 17a-7 under the Investment Company Act of 1940 and were as follows:

	Purchases		Sales
(in thousands)
Columbia Acorn Fund	$	25,228	$	—
Columbia Acorn International		1,372		—
Columbia Acorn USA		578		—
Columbia Acorn International Select		213		—
Columbia Acorn Select		—		24,857

5.  Objectives and Strategies for Investing in Derivative Instruments

Columbia Acorn International uses derivative 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 risks:

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 note provides 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 seek 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 seek 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 six months ended June 30, 2011, Columbia Acorn International entered into 92 forward foreign currency exchange contracts.

The following table is a summary of the value of Columbia Acorn International's derivative instruments as of June 30, 2011.

  Fair Value of Derivative Instruments

	Asset
	Statement of Assets and Liabilities	Fair Value
(in thousands)
	Unrealized appreciation on forward foreign currency exchange contracts	$	3,057
	Liability
	Statement of Assets and Liabilities	Fair Value
(in thousands)
	Unrealized depreciation on forward foreign currency exchange contracts	$	2,796

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The effect of derivative instruments on Columbia Acorn International's Statement of Operations for the six months ended June 30, 2011 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	$	(84	)	$	(11,026	)

6.  Borrowing Arrangements

The Trust participates 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 1.25%. In addition, a commitment fee of 0.125% 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 six months ended June 30, 2011. 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 2012.

7.  Investment Transactions

The aggregate cost of purchases and proceeds from sales, other than short-term obligations, for the six months ended June 30, 2011, were:

Columbia Acorn Fund

(in thousands)
Investment securities
Purchases	$	1,566,628
Proceeds from sales		1,538,048

Columbia Acorn International

(in thousands)
Investment securities
Purchases	$	1,008,306
Proceeds from sales		748,658

Columbia Acorn USA

(in thousands)
Investment securities
Purchases	$	209,631
Proceeds from sales		167,239

Columbia Acorn International Select

(in thousands)
Investment securities
Purchases	$	87,027
Proceeds from sales		149,800

Columbia Acorn Select

(in thousands)
Investment securities
Purchases	$	277,833
Proceeds from sales		506,800

Columbia Thermostat Fund

(in thousands)
Investment securities
Purchases	$	49,334
Proceeds from sales		48,426

8.  Regulatory Settlements with Third Parties

During the year ended December 31, 2010, Columbia Acorn International and Columbia Acorn International Select received payments totaling $446,565 and $46,265, 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" in the Statements of Changes in Net Assets.

9.  Information Regarding Pending and Settled Legal Proceedings

In June 2004, an action captioned John E. Gallus et al. v. American Express Financial Corp. and American Express Financial Advisors Inc. was filed in the United States District Court for the District of Arizona. The plaintiffs allege that they are investors in several American Express Company (now known as legacy RiverSource) mutual funds and they purport to bring the action derivatively on behalf of those funds under the Investment Company Act of 1940. The plaintiffs allege that fees allegedly paid to the defendants by the funds for investment advisory and administrative services are excessive. The plaintiffs seek remedies including restitution and rescission of investment advisory and distribution agreements. The plaintiffs voluntarily agreed to transfer this case to the United States District Court for the District of Minnesota (the District Court). In response to defendants' motion to dismiss the complaint, the District Court dismissed one of plaintiffs' four claims and granted plaintiffs limited discovery. Defendants moved for summary judgment in April 2007. Summary judgment was granted in the defendants' favor on July 9, 2007. The plaintiffs

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Columbia Acorn Family of Funds

Notes to Financial Statements (Unaudited), continued

filed a notice of appeal with the Eighth Circuit Court of Appeals (the Eighth Circuit) on August 8, 2007. On April 8, 2009, the Eighth Circuit reversed summary judgment and remanded to the District Court for further proceedings. On August 6, 2009, defendants filed a writ of certiorari with the U.S. Supreme Court (the Supreme Court), asking the Supreme Court to stay the District Court proceedings while the Supreme Court considers and rules in a case captioned Jones v. Harris Associates, which involves issues of law similar to those presented in the Gallus case. On March 30, 2010, the Supreme Court issued its ruling in Jones v. Harris Associates, and on April 5, 2010, the Supreme Court vacated the Eighth Circuit's decision in the Gallus case and remanded the case to the Eighth Circuit for further consideration in light of the Supreme Court's decision in Jones v. Harris Associates. On June 4, 2010, the Eighth Circuit remanded the Gallus case to the District Court for further consideration in light of the Supreme Court's decision in Jones v. Harris Associates. On December 9, 2010, the District Court reinstated its July 9, 2007 summary judgment order in favor of the defendants. On January 10, 2011, plaintiffs filed a notice of appeal with the Eighth Circuit.

In December 2005, without admitting or denying the allegations, American Express Financial Corporation (AEFC, which is now known as Ameriprise Financial, Inc. (Ameriprise Financial)), entered into settlement agreements with the Securities and Exchange Commission (SEC) and Minnesota Department of Commerce (MDOC) related to market timing activities. As a result, AEFC was censured and ordered to cease and desist from committing or causing any violations of certain provisions of the Investment Advisers Act of 1940, the Investment Company Act of 1940, and various Minnesota laws. AEFC agreed to pay disgorgement of $10 million and civil money penalties of $7 million. AEFC also agreed to retain an independent distribution consultant to assist in developing a plan for distribution of all disgorgement and civil penalties ordered by the SEC in accordance with various undertakings detailed at http://www.sec.gov/litigation/admin/ia-2451.pdf. Ameriprise Financial and its affiliates have cooperated with the SEC and the MDOC in these legal proceedings, and have made regular reports to the RiverSource, Seligman and Threadneedle funds' Boards of Directors/Trustees.

Ameriprise Financial and certain of its affiliates have historically been involved in a number of legal, arbitration and regulatory proceedings, including routine litigation, class actions, and governmental actions, concerning matters arising in connection with the conduct of their business activities. Ameriprise Financial believes that the Funds are not currently the subject of, and that neither Ameriprise Financial nor any of its affiliates are the subject of, any pending legal, arbitration or regulatory proceedings that are likely to have a material adverse effect on the Funds or the ability of Ameriprise Financial or its affiliates to perform under their contracts with the Funds. Ameriprise Financial is required to make 10-Q, 10-K and, as necessary, 8-K filings with the SEC on legal and regulatory matters that relate to Ameriprise Financial and its affiliates. Copies of these filings may be obtained by accessing the SEC website at www.sec.gov.

There can be no assurance that these matters, or the adverse publicity associated with them, will not result in increased fund redemptions, reduced sale of fund shares or other adverse consequences to the Funds. Further, although we believe proceedings are not likely to have a material adverse effect on the Funds or the ability of Ameriprise Financial or its affiliates to perform under their contracts with the Funds, these proceedings are subject to uncertainties and, as such, we are unable to estimate the possible loss or range of loss that may result. An adverse outcome in one or more of these proceedings could result in adverse judgments, settlements, fines, penalties or other relief that could have a material adverse effect on the consolidated financial condition or results of operations of Ameriprise Financial.

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[Excerpt from:]

Columbia Acorn Trust

Management Fee Evaluation of the Senior Officer

Prepared Pursuant to the New York Attorney General's
Assurance of Discontinuance

May 2011

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Introduction

The New York Attorney General's Assurance of Discontinuance (Order) entered into by Columbia Management Advisors, LLC (CMA) and Columbia Management Distributors, Inc., (CMDI) in February 2005, allows CMA to manage or advise a mutual fund only if the trustees of the fund appoint a Senior Officer to perform specified duties and responsibilities. Among these responsibilities is "managing the process by which proposed management fees (including but not limited to, advisory fees) to be charged the [funds] are negotiated so that they are negotiated in a manner which is at arms' length and reasonable and consistent with this Assurance of Discontinuance."

The Columbia Acorn Trust and Wanger Advisors Trust (collectively, the Trusts) and each series thereof (the Acorn funds, WAT funds or collectively, the Funds) are overseen by the same Board of Trustees (Board). The Order provides that this Board must determine the reasonableness of proposed management fees by using either an annual competitive bidding process supervised by the Senior Officer or Independent Fee Consultant, or by obtaining an annual independent written evaluation prepared by or under the direction of the Senior Officer or the Independent Fee Consultant.

Management fees are only part of the costs and expenses paid by mutual fund shareholders. Fund expenses can vary depending upon the class of shares held but usually include: (1) advisory fees to compensate analysts and portfolio managers for stock research and portfolio management, as well as the cost of operating a trading desk; (2) administrative expenses incurred to prepare registration statements and tax returns, calculate the funds' net asset values, maintain effective compliance procedures and perform recordkeeping services; (3) transfer agency costs for establishing accounts, accepting and disbursing funds, as well as overseeing trading in fund shares; (4) custodial expenses incurred to hold the securities purchased by the funds; and (5) distribution expenses, including commissions paid to brokers that sell the fund shares to investors. Management fees consist of (1) and (2), but not the other services.

Columbia Wanger Asset Management, LLC (CWAM), is the adviser to the Funds, and at present is wholly owned by Ameriprise Financial, Inc. (Ameriprise). The name Columbia Management or Columbia, is used to refer to the group of entities that manage or provide services to funds bearing the brand name Columbia. These entities include Columbia Management Investment Advisers, (CMIA), the successor entity to CMA, Columbia Management Investment Services, Inc. (CMIS) and Columbia Management Investment Distributors, Inc. (CMID), the successor entity to CMDI. The Columbia asset management business, formerly owned by Bank of America Corporation (Bank of America), is now owned by Ameriprise.

The Change of Ownership

On September 29, 2009, Bank of America entered into a Purchase Agreement with Ameriprise providing for, among other things, the sale of CWAM to Ameriprise and the acquisition by Ameriprise of certain assets of Columbia. The sale closed on May 1, 2010. A new advisory agreement is required under these circumstances. In advance of that closing, Columbia and Ameriprise proposed that the Trusts continue, in substance, the then existing advisory agreement governing portfolio management, and the administration services agreement governing certain administration and clerical services. They proposed no material changes to these agreements, no change in services and no changes in fee levels, only those changes necessary to effect the change of ownership. The Board of Trustees approved the new advisory agreements, and on May 27, 2010, shareholders voted to approve them too. The investment management team responsible for the Funds remained with CWAM following the Ameriprise acquisition.

The Investment Company Act of 1940 (1940 Act) effectively bars an increase in management fees for two years following a change in ownership of a fund's advisor (other than for bona fide additional investment advisory services); the purpose of this prohibition is to preclude management from financing the purchase through increased advisory fees. Ameriprise has represented to the Board that it intends to comply with these restrictions, and does not seek increased management fees at this time. Rather, Ameriprise seeks only to renew the advisory and related agreements on their existing terms.

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Requirements of the Order

The Order applies to any successor to substantially all the assets of CMDI and CMA. Thus, it applies to CMIA and CMID as successors to CMA and CMDI. Under the Order, a fee evaluation must precede the execution of new or the extension of existing advisory and administration services agreements. The existing agreements continue in effect until July 31, 2011.

In conformity with the terms of the Order and past evaluations, this Evaluation addresses only the advisory and administration contracts, and does not extend to the Funds' underwriting and transfer agency agreements.

According to the Order, the Senior Officer's evaluation must consider a number of factors. These factors parallel the standard set forth in the Gartenberg case. They are following:

(1)  Management fees (including components thereof) charged to institutional and other clients of CWAM for like services;

(2)  Management fees (including any components thereof) charged by other mutual fund companies for like services;

(3)  Costs to CWAM and its affiliates of supplying services pursuant to the management fee agreements, excluding any intra-corporate profit;

(4)  Profit margins of CWAM and its affiliates from supplying such services;

(5)  Possible economies of scale as the Funds grow larger; and

(6)  The nature and quality of CWAM's services, including the performance of each Fund.

In 2004, the Boards of the two Trusts, then separate groups, each appointed me Senior Officer under the Order. They also determined not to pursue a competitive bidding process and instead, charged me with the responsibility of evaluating the Funds' proposed advisory and administration fee contracts with CWAM in conformity with the requirements of the Order. In discharging their responsibilities, the independent Trustees have also consulted independent, outside counsel. The Board has asked that I prepare this Evaluation.

Scope of this Evaluation

This Evaluation is qualified in two respects. First, assessing such factors as cost of service, profitability, projected economies of scale, and expected quality of service, involves, at present, a significant element of uncertainty. Ameriprise and Columbia hope to effect cost savings by virtue of the increased scale of their operations. The integration of the two organizations is not, however, complete at this time, so the anticipated benefits are impossible to quantify now and hence cannot effectively be weighed in assessing the reasonableness of the proposed management fee. Profitability data is, to some extent, based on pro forma financial statements. At the same time, Ameriprise and Columbia have assured the Board that the Funds will not suffer diminished services as a result of the combination, nor do they propose to change the fee levels set forth in the existing advisory and administration services agreements. The upshot is that the Fund shareholders will, if the advisory agreements are renewed and asset levels do not decrease, pay no more than they do now, but it is too early to determine whether the change in ownership will result in material changes in the calculus of assessing the fairness of the management fee. Of necessity this must be left to future evaluations.

A second consideration concerns the new funds recently approved by the Board of Trustees. Earlier this year, CWAM and Ameriprise proposed two new Acorn funds: Columbia Acorn Emerging Markets Fund (Acorn Emerging Markets), and Columbia Acorn European Fund (Acorn European). I issued a fee evaluation in February 2011 addressing the management fees proposed for those new funds. In March 2011, the Board approved amendments to the advisory and other agreements necessary to launch the new funds. They have not yet, however, been offered. Consequently, there is nothing to add here to the evaluation done in February, so this Evaluation does not address those funds.

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Process and Independence

The objectives of the Order are to ensure the independent evaluation of the management fees paid by the Funds as well as to insure that all relevant factors are considered. In my view, this contract process has been conducted at arms-length and with independence in gathering, considering and evaluating all relevant data. At the outset of the process, the Trustees sought and obtained from Ameriprise and Columbia a comprehensive compilation of data regarding Fund performance and expenses, adviser profitability, and other information. The Trustees, acting through their Contract Committee evaluated this information thoroughly, and met often to discuss it. Performance and expense data was obtained from both Morningstar and Lipper, the leading consultants in this area. The rankings prepared by Morningstar and Lipper were independent and prepared in conformity with the methodologies employed by those organizations. Counsel for the Funds and the Independent Trustees considered, as did I, the terms and conditions of the proposed contracts.

My evaluation of the advisory contracts was shaped, as it has been in the past, by my experience as Chief Compliance Officer of the Trusts (CCO). As CCO, I report solely to the Board and have no reporting obligation to, or employment relationship with, Ameriprise or its affiliates. I have commented on compliance matters in evaluating the quality of service provided by CWAM.

This Report, its supporting materials and the data contained in other materials submitted to the Contract Committee, in my view, provide a thorough factual basis upon which the Board, in consultation with independent counsel as it deems appropriate, may conduct management fee negotiations that are in the best interests of the Funds' shareholders.

The Fee Reductions Mandated under the Order

Under the terms of the Order, Columbia agreed to secure certain management fee reductions for the mutual funds advised by its affiliate investment advisers. In some instances, breakpoints were also established. Although neither CWAM nor the Trusts was a party to the Order, CWAM offered and the Board accepted certain advisory fee reductions during 2005. By the terms of the Order, these fees could not be increased before November 30, 2009, and, in fact, have not been increased since. As a result of the Ameriprise acquisition, the Investment Company Act precludes any increases in management fees before May 2012 (other than for bona fide additional investment advisory services). Therefore, CWAM and Ameriprise propose the continuation of the contracts and management fees as they now exist; no increases in these fees are sought, and no reductions offered.

Conclusions

My review of the data and other material above leads to the following conclusions with respect to the factors identified in the Order.

A.  Fund Performance

The Domestic Funds: The Acorn Fund has achieved good performance over the past five years, and excellent results over longer periods. Acorn Select and Wanger Select have enjoyed better than average investment returns over the past five years, but have suffered reversals in more recent periods. Both funds expose investors to greater relative risk than the other domestic Funds. Acorn USA and its parallel, Wanger USA are the weakest performers, falling behind their benchmark and peer medians over one and five years. Thermostat is unique and therefore difficult to assess, but has outperformed its benchmark and now enjoys strong rankings from Morningstar.

The International Funds: The international Funds have delivered excellent results over the past five years, and done so while exposing investors to less risk than competing funds. They have also outperformed their benchmarks during this period, but recent results have been more restrained. The international Funds enjoy positive "alpha," confirming the value of their portfolio managers.

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B.  Management Fees Relative to Peers

  There is significant variance in management fee rankings across the Funds. Acorn International is the only fund that was ranked in the top quartile by both Morningstar and Lipper. The other Acorn funds tend to fall around the medians identified by one or the other service. The WAT funds are uniformly more expensive than their peers.

C.  Management Fees Relative to Institutional Account and Other Mutual Fund Accounts

  CWAM's focus is on its mutual funds. The few institutional accounts it does manage vary in rate structures. Some pay advisory fees commensurate with or higher than the Acorn and WAT funds. In a few instances, however, institutional accounts pay lower advisory fees than do the Acorn funds. One such institutional account is significant in size and has been under CWAM's management for over 33 years. Furthermore, CWAM performs sub-advisory services for mutual funds managed by Ameriprise affiliates, CWAM's parent organization, at rates that are lower than those paid by the parallel Acorn funds, though sub-advisory services usually differ from those necessary for the full support of a mutual fund.

D.  Administrative Services

  The Acorn and WAT funds' administrative fees are within the range of fees charged by competitors, but these rankings suffer from a lack of uniformity in the scope of services encompassed by the fee. CWAM provides excellent administrative support for all the Funds.

E.  Costs and Benefits to CWAM and its Affiliates

  CWAM's direct costs do not appear excessive. Overhead and indirect costs allocated to CWAM by its parent organization, however, are significant and have varied considerably over the years. CWAM's affiliates report operating losses and although the allocations leading to these losses may bear closer scrutiny, Ameriprise affiliates do not appear to enjoy excessive "fall out" benefits from CWAM's advisory agreement with the Funds. CWAM continues, however, to enjoy substantial benefits from the use of "soft dollar" payments for research.

F.  Profitability

  CWAM's profit margins may be in the upper range of its competitors, but peer profitability is difficult to assess given differences in products, operations and other factors. Furthermore, there is limited public information available with regard to the profitability of investment advisers.

G.  Economies of Scale

  Economies of scale do exist at CWAM, and the Board has instituted breakpoints that reduce fess as assets increase. Though asset levels have recovered from recent lows, sustained asset growth will be required to trigger additional fee reductions under the current schedule.

H.  Nature and Quality of Service

  This category includes a variety of considerations that are difficult to quantify, yet can have a significant bearing on the performance of the Acorn and WAT funds. Several areas merit comment: (1) CWAM has maintained its investment management capacity and an experienced staff; and (2) CWAM has a reasonably designed compliance program that protects shareholders.

I.  Process

  In my opinion, the process of negotiating an advisory contract for the Funds has been conducted thoroughly and at arms' length. The Board's Contract Committee has sought and obtained extensive data bearing on the reasonableness of the management fees proposed by CWAM. The Trustees have sufficient information to evaluate management's proposal, and negotiate contract terms that are in the best interests of fund shareholders.

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Recommendation

According to Morningstar, Acorn USA and Wanger USA have delivered performance below peer medians for the past one and five years, while imposing management fees that exceed them. Management has fashioned various initiatives to improve performance, and the Trustees should continue to monitor both Funds closely to assess the impact of those initiatives.

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Board Approval of the Advisory Agreement

Columbia Acorn Trust (the Trust) has an investment advisory agreement (the Advisory Agreement) with Columbia Wanger Asset Management, LLC (CWAM) under which CWAM manages the Columbia Acorn Funds (the Funds). More than 75% of the trustees of the Trust (the Trustees) are comprised of persons who have no direct or indirect interest in the Advisory Agreement and are not interested persons (as defined in the Investment Company Act of 1940, as amended (the 1940 Act)) of the Trust (the Independent Trustees). The Trustees oversee the management of each Fund and, as required by law, determine at least annually whether to continue the Advisory Agreement for each Fund.

The Contract Committee of the Board (the Committee), which is comprised solely of Independent Trustees, makes recommendations to the Board regarding any proposed continuation of the Advisory Agreement. After the Committee has made its recommendations, the full Board determines whether to approve continuation of the Advisory Agreement. The Board also considers matters bearing on the Advisory Agreement at its various meetings throughout the year, meets at least quarterly with CWAM's portfolio managers and receives monthly reports from CWAM on the performance of the Funds.

In connection with their most recent consideration of the Advisory Agreement for each Fund, the Committee and all Trustees received and reviewed a substantial amount of information provided by CWAM, Columbia Management Investment Advisers, LLC (Columbia Management) and Ameriprise Financial, Inc. (Ameriprise), in response to written requests from the Independent Trustees and their independent legal counsel. Throughout the process, the Trustees had numerous opportunities to ask questions of and request additional materials from CWAM, Columbia Management and Ameriprise.

During each meeting at which the Committee or the Independent Trustees considered the Advisory Agreement, they met in executive session with their independent legal counsel. The Committee also met with representatives of CWAM, Columbia Management and Ameriprise on several occasions. In all, the Committee convened formally on five separate occasions to consider the continuation of the Advisory Agreement. The Board and/or some or all of the Independent Trustees met on other occasions to receive the Committee's status reports, receive presentations from CWAM, Columbia Management and Ameriprise representatives, and to discuss outstanding issues. In addition, the Investment Performance Analysis Committee of the Board, also comprised exclusively of Independent Trustees, reviewed the performance of the Funds and presented its findings to the Board and the Committee throughout the year. The Compliance Committee also provided information to the Committee with respect to relevant matters.

The Trustees reviewed the Advisory Agreement, as well as certain information obtained through CWAM's, Columbia Management's and Ameriprise's responses to independent legal counsel's questionnaires. In addition, the Trustees reviewed the Management Fee Evaluation dated May 2011 (the Fee Evaluation) prepared by the Trust's chief compliance officer, senior vice president and general counsel, who also serves as the Trust's "Senior Officer," as contemplated by the Assurance of Discontinuance dated February 9, 2005 among former affiliates of CWAM and the Office of the New York Attorney General. A summary of the Fee Evaluation is included in this report.

The materials reviewed by the Committee and the Trustees included, among other items, (i) information on the investment performance of each Fund and of independently selected peer groups of funds and of the Funds' performance benchmarks over various time periods, (ii) information on each Fund's advisory fees and other expenses, including information comparing the Fund's fees and expenses to those of peer groups of funds and information about any applicable expense limitations and fee breakpoints, (iii) data on sales and redemptions of Fund shares, and (iv) information on the profitability to CWAM and Ameriprise, as well as potential "fall-out" or ancillary benefits that CWAM and its affiliates may receive as a result of their relationships with the Funds. The Trustees also considered other information such as (i) CWAM's financial condition, (ii) each Fund's investment objective and strategy, (iii) the size, education and experience of CWAM's investment staff and its use of technology, external research and trading cost measurement tools, (iv) the portfolio manager compensation framework, (v) the allocation of the Funds' brokerage, and the use of "soft" commission dollars to pay for research products and services, and (vi) the resources devoted to, and the record of compliance with, the Funds' investment policies and restrictions, policies on personal securities transactions and other compliance policies.

At a meeting held on June 8, 2011, upon recommendations of the Committee, the Board of Trustees unanimously approved the continuation of the Advisory Agreement.

In considering the continuation of the Advisory Agreement, the Trustees reviewed and analyzed various factors that they determined were relevant, none of which by itself was considered dispositive. The material factors and conclusions that formed the basis for the Trustees' determination to approve the continuation of the Advisory Agreement are discussed below.

Nature, quality and extent of services. The Trustees reviewed the nature, quality and extent of the services provided by CWAM and its affiliates to the Funds under the Advisory Agreement, taking into account the investment objective and strategy of each Fund and knowledge gained from meetings with management, which were held on at least a quarterly basis. In addition, the Trustees reviewed the available

93

Board Approval of the Advisory Agreement, continued

resources and key personnel of CWAM and its affiliates, especially those providing investment management services to the Funds. The Trustees also considered other services provided to the Funds by CWAM and its affiliates, including: managing the execution of portfolio transactions and selecting broker-dealers for those transactions; monitoring adherence to the Funds' investment restrictions; producing shareholder reports; providing support services for the Board and committees of the Board; communicating with shareholders; serving as the Funds' administrator; and overseeing the activities of the Funds' other service providers, including monitoring for compliance with various policies and procedures as well as applicable securities laws and regulations.

The Trustees concluded that the nature, quality and extent of the services provided by CWAM and its affiliates to each Fund under the Advisory Agreement were appropriate for the Funds and that the Funds were likely to benefit from the continued provision of those services by CWAM. They also concluded that CWAM currently had sufficient personnel, with appropriate education and experience, to serve the Funds effectively, and that the firm had demonstrated its continuing ability to attract and retain well-qualified personnel. In addition, they took note of the quality of CWAM's compliance record.

Performance of the Funds. The Trustees received and considered detailed performance information at various meetings of the Board, the Committee and the Investment Performance Analysis Committee of the Board throughout the year. They reviewed information comparing each Fund's performance with that of its benchmark(s) and with the performance of comparable funds and peer groups as identified by Lipper Inc. (Lipper) and Morningstar, Inc. (Morningstar). The Trustees evaluated the performance of the Funds over various time periods, including over the one-, three- and five-year periods ending December 31, 2010. The Trustees also considered peer performance rankings based on a rolling five-year period.

The Trustees noted that the international Funds have delivered excellent results over the past five years, and have done so while exposing investors to less risk than competing funds, according to Morningstar. They considered that the domestic Funds have had mixed results. Columbia Acorn Fund has achieved good performance over the one- and three-year periods, and slightly underperformed its peers over the five-year period, ending December 31, 2010; the Fund had excellent results over longer periods. Columbia Acorn Select had better than average results measured against its peers over the three- and five-year periods ending December 31, 2010, but underperformed more recently. Columbia Acorn Select outperformed its benchmark for the five-year period but underperformed over the one- and three-year periods ending December 31, 2010. Columbia Acorn USA fell behind its benchmark and peer group medians over the one-, three- and five-year periods ending December 31, 2010, and Columbia Thermostat Fund outperformed its benchmark (an equally weighted custom composite of the Fund's primary equity and debt indexes) over the one-, three- and five- year periods ending December 31, 2010, and enjoyed strong rankings from Morningstar over each of these periods. The Trustees noted that the Investment Performance Analysis Committee of the Board concluded that Fund performance was generally satisfactory, except that Columbia Acorn USA's performance had slipped below the Lipper and Morningstar medians during the past year. The Trustees considered that CWAM had taken and was taking a number of corrective steps with respect to Columbia Acorn USA's underperformance and that the Investment Performance Analysis Committee of the Board was monitoring the Fund's performance.

The Trustees concluded that, although past performance is not necessarily indicative of future results, the strong overall longer-term performance record of the Funds was an important factor in their evaluation of the quality of services provided by CWAM under the Advisory Agreement for each Fund.

Costs of Services and Profits Realized by CWAM. At various Committee and Board meetings, the Trustees examined detailed information on the fees and expenses of each Fund in comparison to information for comparable funds provided by Lipper and Morningstar. The Trustees reviewed data from Lipper and Morningstar and noted that in general the Funds' total net operating expenses were below their median peer group rankings, with each Fund having lower total net operating expenses than its Lipper peer group median and only Columbia Acorn USA having total net operating expenses above its Morningstar peer group median. As noted in the Fee Evaluation, the actual advisory fees paid by Columbia Acorn Select and Columbia Acorn USA were higher than the median advisory fee of the Funds' Lipper and Morningstar peer groups and the actual advisory fee paid by Columbia Acorn International Select was higher than the median advisory fee of the Fund's Lipper peer group, but not of its Morningstar peer group. The actual advisory fees paid by Columbia Acorn Fund, Columbia Acorn International and Columbia Thermostat Fund were lower than the median advisory fee of the Funds' Morningstar and Lipper peer groups.

The Trustees also considered that Ameriprise represented and agreed that advisory fees would not be raised for the two years following the close of its acquisition of CWAM (May 1, 2010) pursuant to Section 15(f) of the 1940 Act.

The Trustees also reviewed the advisory fee rates charged by CWAM for managing other investment companies (including the Columbia Wanger Funds), sub-advised funds and other institutional separate accounts, as detailed in the Fee Evaluation. The Trustees noted that the Funds' advisory fees were generally comparable to the Columbia Wanger Funds' advisory fees at

94

the same asset levels. The Trustees also examined CWAM's institutional separate account fees for various investment strategies; in some cases those fees were higher than the advisory fees charged to the Funds, and in a few instances the fees were lower. The Trustees noted that CWAM performs significant additional services for the Funds that it does not provide to sub-advised funds or non-mutual fund clients, including administrative services, oversight of the Funds' other service providers, Trustee support, regulatory compliance and numerous other services, and that, in servicing the Funds, CWAM assumes many legal risks that it does not assume in servicing many of its non-fund clients.

The Trustees concluded that the rates of advisory fees payable to CWAM were reasonable in relation to the nature and quality of the services to be provided. The Trustees also concluded that the Funds' overall expense ratios were reasonable, considering the quality of the services provided by CWAM and its affiliates and the investment performance of the Funds.

The Trustees reviewed the analysis of the historic profitability of CWAM in serving as each Fund's investment adviser and of CWAM and its affiliates in their relationships with each Fund. The Committee and Trustees met on several occasions with representatives from Ameriprise to discuss its methodologies for calculating profitability and allocating costs. They considered that Ameriprise calculated profitability and allocated costs on a contract-by-contract and fund-by-fund basis. The Trustees also considered the methodology used by CWAM and Ameriprise in determining compensation payable to portfolio managers and the competitive market for investment management talent. The Trustees were also provided with profitability information from Lipper and Strategic Insight, which compared CWAM's profitability to other similar investment advisers in the mutual fund industry. The Trustees concluded that CWAM's and its affiliates' profits were within a reasonable range of those of competitors with similar business models. The Trustees discussed, however, that profitability comparisons among fund managers may not always be meaningful due to the lack of consistency in data, small number of publicly-owned managers, and the fact that profitability of any investment manager is affected by numerous factors, including its particular organizational structure, the types of funds and other accounts managed, other lines of business, expense allocation methodology, capital structure and cost of capital.

Economies of Scale. At various Committee and Board meetings and other informal meetings, the Trustees considered information about the extent to which CWAM realizes economies of scale in connection with an increase in Fund assets. The Trustees also discussed the potential for Fund sales growth. The Trustees noted that the advisory fee schedule for each Fund, other than Columbia Thermostat Fund, which has relatively modest assets, includes breakpoints in the rate of fees at various asset levels. The Trustees concluded that the fee structure of each Fund was reflective of a sharing between CWAM and the Funds of economies of scale.

Other Benefits to CWAM. The Trustees also reviewed benefits that accrue to CWAM and its affiliates from their relationships with the Funds, as outlined in the Fee Evaluation. They noted that the Funds' transfer agency services are performed by Columbia Management Investment Services Corp., an affiliate of Ameriprise, which receives compensation from the Funds for its services provided. They considered that an affiliate of Ameriprise, Columbia Management Investment Distributors, Inc. (CMID), serves as the Funds' distributor under a distribution agreement, and that it receives fees under the Trust's Rule 12b-1 Plan, most of which CMID paid to broker-dealers. In addition, Columbia Management provides sub-administration services to the Funds. The Committee received information regarding the profitability of each Fund agreement with CWAM affiliates. The Committee and the Board also reviewed information about and discussed the capabilities of each affiliated entity in performing its duties.

The Trustees considered other ways that the Funds and CWAM may potentially benefit from their relationship with each other. For example, the Trustees considered CWAM's use of commissions paid by each Fund on its portfolio brokerage transactions to obtain research products and services benefiting the Funds and/or other clients of CWAM. The Committee reviewed CWAM's annual "soft dollar" report and met with representatives from CWAM to review CWAM's soft dollar spending. The Committee also considered that the Compliance Committee of the Board regularly reviewed third-party prepared reports that evaluated the quality of CWAM's execution of the Funds' portfolio transactions. The Trustees determined that CWAM's use of the Funds' "soft" commission dollars to obtain research products and services was consistent with current regulatory requirements and guidance. They also concluded that CWAM benefits from the receipt of proprietary research products and services acquired through commissions paid on portfolio transactions of the Funds, and that the Funds benefit from CWAM's receipt of those products and services as well as research products and services acquired through commissions paid by other clients of CWAM.

After full consideration of the above factors, as well as other factors that were instructive in evaluating the Advisory Agreement, the Trustees, including the Independent Trustees, unanimously concluded that the continuation of the Advisory Agreement was in the best interest of each Fund. On June 8, 2011, the Trustees approved continuation of the Advisory Agreement through July 31, 2012.

95

Columbia Acorn Family of Funds

Second Quarter Class Z Share Information (Unaudited)

Minimum Initial Investment in
all Funds	$0 to $2,000,
	available only to
	certain eligible
	investors
Minimum Subsequent Investment in all Funds	$100
Exchange Fee	None

Columbia Acorn Fund	ACRNX
Management Fee		0.64	%
12b-1 Fee		None
Other Expenses		0.11	%
Net Expense Ratio		0.75	%
Columbia Acorn International	ACINX
Management Fee		0.76	%
12b-1 Fee		None
Other Expenses		0.19	%
Net Expense Ratio		0.95	%
Columbia Acorn USA	AUSAX
Management Fee		0.86	%
12b-1 Fee		None
Other Expenses		0.13	%
Net Expense Ratio		0.99	%
Columbia Acorn International Select	ACFFX
Management Fee		0.94	%
12b-1 Fee		None
Other Expenses		0.21	%
Net Expense Ratio		1.15	%
Columbia Acorn Select	ACTWX
Management Fee		0.81	%
12b-1 Fee		None
Other Expenses		0.16	%
Net Expense Ratio		0.97	%
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 six months ended June 30, 2011. Some share classes of Columbia Acorn Select and Columbia Acorn International Select include the effect of the voluntary undertaking by Columbia Wanger Asset Management, LLC (CWAM) to waive fees and/or reimburse the Funds for any 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, in excess of the annual rate of the Funds as follows:

Fund	Class Z
Columbia Acorn International Select		1.45	%
Columbia Acorn Select		1.35	%

    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 investments 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 waiver/reimbursement arrangement is contractual through April 30, 2012. There is no guarantee that this arrangement will continue thereafter.

  *  Does not include estimated fees and expenses of 0.65% incurred by the Fund from the underlying portfolio funds in which it invests.

96

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97

Columbia Acorn Family of Funds

Trustees

Laura M. Born

Chair of the Board

Steven N. Kaplan

Vice Chair of the Board

Michelle L. Collins

Maureen M. Culhane

Margaret M. Eisen

John C. Heaton

Charles P. McQuaid

Allan B. Muchin

David J. Rudis

David B. Small

Ralph Wanger (Trustee Emeritus)

Officers

Charles P. McQuaid

President

Ben Andrews

Vice President

Robert A. Chalupnik

Vice President

Michael G. Clarke

Assistant Treasurer

Joseph F. DiMaria

Assistant Treasurer

P. Zachary Egan

Vice President

John M. Kunka

Assistant Treasurer

Joseph C. LaPalm

Vice President

Bruce H. Lauer

Vice President, Secretary and Treasurer

Louis J. Mendes III

Vice President

Robert A. Mohn

Vice President

Christopher J. Olson

Vice President

Christopher O. Petersen

Assistant Secretary

Scott R. Plummer

Assistant Secretary

Linda K. Roth-Wiszowaty

Assistant Secretary

Robert P. Scales

Chief Compliance Officer, Chief Legal Officer,
Senior Vice President and General Counsel

Investment Adviser

Columbia Wanger Asset Management, LLC
227 West Monroe Street, Suite 3000
Chicago, Illinois 60606

1-800-922-6769

Distributor

Columbia Management Investment Distributors, Inc.
225 Franklin Street
Boston, Massachusetts 02110

Transfer Agent, Dividend Disbursing Agent

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

1-800-345-6611

Legal Counsel to the Funds

Perkins Coie 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, is available from the SEC's website. Information regarding how the Funds voted proxies relating to portfolio securities is also available at www.columbiamanagement.com under "About Us." From there, click on "Disclosures."

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.

Investors should consider the investment objectives, risks, charges and expenses of a mutual fund carefully before investing. For a free prospectus, which contains this and other important information about the funds, visit www.columbiamanagement.com. Read the prospectus carefully before investing.

Columbia Acorn Funds are distributed by Columbia Management Investment Distributors, Inc., member FINRA and managed by Columbia Wanger Asset Management, LLC.

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

www.columbiamanagement.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.

98

Columbia Management^®

Columbia Acorn Family of Funds
Class Z Shares

Semiannual Report, June 30, 2011

For More Information

You'll find more information about the Columbia Acorn Family of 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 Investment Services Corp.
P. O. Box 8081 Boston, MA 02266-8081

By Telephone: 800.345.6611

Online: www.columbiamanagement.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, LLC, 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 is a series, is 811-01829.

© 2011 Columbia Management Investment Advisers, LLC. All rights reserved.

225 Franklin Street, Boston, MA 02110

800.345.6611 www.columbiamanagement.com

C-1565 C (8/11) 122754

Q2 2011

Columbia Acorn Family of Funds

Class A, B, C and I Shares

Managed by Columbia Wanger Asset Management, LLC

Second Quarter Report

June 30, 2011

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 • No bank guarantee • May lose value

2011 Mid-Year Distributions

The following table lists the mid-year distributions for Columbia Acorn Fund, Columbia Acorn International, Columbia Acorn International Select, Columbia Acorn Select and Columbia Thermostat Fund. Columbia Acorn USA did not have mid-year distributions. The record date was June 7, 2011, and the ex-dividend date and the payable date was June 8, 2011.

	Short-term Capital Gains		Long-term Capital Gains		Ordinary Income		Reinvestment Price
Columbia Acorn Fund Class A		None	$	0.3037	$	0.0163	$	29.46
Columbia Acorn Fund Class B		None	$	0.3037		None	$	27.26
Columbia Acorn Fund Class C		None	$	0.3037		None	$	26.95
Columbia Acorn Fund Class I		None	$	0.3037	$	0.0857	$	30.41
Columbia Acorn International Class A		None		None	$	1.0167	$	41.00
Columbia Acorn International Class B		None		None	$	0.9985	$	39.97
Columbia Acorn International Class C		None		None	$	0.9448	$	39.82
Columbia Acorn International Class I		None		None	$	1.0214	$	41.12
Columbia Acorn International Select Class A		None		None	$	0.3158	$	28.90
Columbia Acorn International Select Class B		None		None	$	0.1591	$	27.64
Columbia Acorn International Select Class C		None		None	$	0.1199	$	27.51
Columbia Acorn International Select Class I		None		None	$	0.4186	$	29.21
Columbia Acorn Select Class A		None		None	$	0.3844	$	26.05
Columbia Acorn Select Class B		None		None	$	0.2283	$	24.36
Columbia Acorn Select Class C		None		None	$	0.1917	$	24.16
Columbia Acorn Select Class I		None		None	$	0.4746	$	26.76
Columbia Thermostat Fund Class A		None		None	$	0.1563	$	12.76
Columbia Thermostat Fund Class B		None		None	$	0.1387	$	12.82
Columbia Thermostat Fund Class C		None		None	$	0.1103	$	12.81

Net Asset Value Per Share as of 06/30/11

	Columbia Acorn Fund		Columbia Acorn International		Columbia Acorn USA		Columbia Acorn International Select		Columbia Acorn Select		Columbia Thermostat Fund
Class A	$	30.95	$	41.02	$	30.01	$	28.69	$	27.50	$	12.98
Class B	$	28.62	$	39.97	$	27.79	$	27.42	$	25.70	$	13.04
Class C	$	28.30	$	39.82	$	27.57	$	27.29	$	25.49	$	13.02
Class I	$	31.96	$	41.15	$	31.18	$	29.00	$	28.25		NA

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's 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.

Columbia Acorn Funds News

Introducing Columbia^SM Acorn® Emerging Markets Fund and Columbia^SM Acorn® European Fund

On August 22, 2011, we launched two new Columbia Acorn Funds: Columbia Acorn Emerging Markets Fund and Columbia Acorn European Fund. These Funds utilize Columbia Wanger Asset Management's time-tested approach to investing, which centers on finding small- to mid-cap stocks in growing businesses with solid long-term prospects. In recent years, our nine international and global analysts have visited over 50 countries in search of investment ideas. These analysts include the portfolio managers running our new Funds, each of whom has exhibited excellent stock-picking skills.

Within the emerging markets, we've noted that most funds invest in large-cap stocks. Their focus is often commodity producers, whose businesses are tied to world macroeconomics, or financial companies, some of which may be quite risky. By focusing on smaller stocks, Columbia Acorn Emerging Markets Fund invests in what we believe to be more innovative, well-run niche businesses, priced at reasonable valuations. We believe that these types of companies should benefit from providing sought-after products and services to growing numbers of local, middle-class consumers, who have increasing spending power. We also believe that many of these companies experience lower levels of competition and better opportunities to internally reinvest profits than larger cap or developed market companies.

Likewise, Columbia Acorn European Fund has a small- to mid-cap stock focus. Because European companies operate in fairly small domestic markets, many are adept at creating niche products that have international appeal. European companies lead the world in machine tool manufacturing, products used to promote energy efficiency, luxury goods items, rail technology and some areas of medical technology. These products are needed, or wanted, in both developed and developing world markets. The integration of the European Union into a single trade zone with a common currency has created greater efficiency and productivity within the region, and opportunities to improve the infrastructure in Central and Eastern Europe are plentiful. Columbia Acorn European Fund's managers have extensive experience investing within the European markets and manage a similar offshore fund, Wanger European Smaller Companies Fund, which is not available to U.S.-domiciled investors.

I am personally investing in both Funds, as are the new Funds' portfolio managers. The Funds entail specific risks that are outlined in their prospectuses, and they may not be suitable for all investors. If interested, please call 1-800-922-6769 or your broker for a prospectus.

New Co-manager Named to Columbia Acorn Select Investment Team

I am pleased to announce that Robert Chalupnik has been named co-manager of Columbia Acorn Select, effective May 1, 2011. Since 2000, Rob has followed industrial stocks as a Columbia Wanger Asset Management analyst. Rob has excelled in finding growing niche businesses selling at reasonable prices. Over his 10 years as an analyst, he has distinguished himself by substantially beating his custom benchmark, which is comprised of most of the industrial stocks included in the Russell 2500 Index. Three of Rob's finds were among the top-10 positions in Columbia Acorn Fund at the end of period. Rob has worked with Columbia Acorn Select lead portfolio manager Ben Andrews since January of this year and together they have added what we believe to be some of Columbia Wanger Asset Management's best ideas into Columbia Acorn Select. Ben remains lead manager of the Fund and welcomes Rob in his new role.

Charles P. McQuaid

President and Chief Investment Officer
Columbia Wanger Asset Management, LLC

Investors should consider the investment objectives, risks, charges and expenses of a mutual fund carefully before investing. For a free prospectus, which contains this and other important information about the fund, visit columbiamanagement.com. The prospectus should be read carefully before investing.

The 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.

There is no guarantee that any investment strategy will deliver favorable results. The market value of securities and currencies may fall or fail to rise. Market risk may affect a single issuer, sector of the economy, industry or the market as a whole. Investments in foreign securities involve certain risks not associated with investments in U.S. companies, due to political, regulatory, economic, social and other conditions or events occurring in the country, as well as fluctuations in currency and the risks associated with less developed custody and settlement practices. Risks are particularly significant in emerging markets. Investments in small-capitalization companies involve greater risks and volatility than investments in larger, more established companies. See the prospectus for more information on these and other risks associated with the Fund.

Columbia Acorn Family of Funds

Table of Contents

Share Class Performance	1
Fund Performance vs. Benchmark	2
Description of Indexes	3
Squirrel Chatter II: Shale Gas Returns, Transforming the Energy Outlook	4
Understanding Your Expenses	8
Columbia Acorn Fund
In a Nutshell	10
At a Glance	11
Major Portfolio Changes	22
Statement of Investments	24
Columbia Acorn International
In a Nutshell	12
At a Glance	13
Major Portfolio Changes	38
Statement of Investments	40
Portfolio Diversification	49
Columbia Acorn USA
In a Nutshell	14
At a Glance	15
Major Portfolio Changes	50
Statement of Investments	51

Columbia Acorn International Select
In a Nutshell	16
At a Glance	17
Major Portfolio Changes	58
Statement of Investments	59
Portfolio Diversification	63
Columbia Acorn Select
In a Nutshell	18
At a Glance	19
Major Portfolio Changes	64
Statement of Investments	65
Columbia Thermostat Fund
In a Nutshell	20
At a Glance	21
Statement of Investments	70
Columbia Acorn Family of Funds
Statements of Assets and Liabilities	72
Statements of Operations	73
Statements of Changes in Net Assets	74
Financial Highlights	78
Notes to Financial Statements	90
Management Fee Evaluation of the Senior Officer	98
Board Approval of the Advisory Agreement	103
Columbia Acorn Family of Funds Information	106

Columbia Acorn Funds

Share Class Performance Average Annual Total Returns through 6/30/11

	Class A						Class B*						Class C						Class I†
	Without Sales Charge			With Sales Charge			Without Sales Charge			With Sales Charge			Without Sales Charge			With Sales Charge			Without Sales Charge
Columbia Acorn Fund (10/16/00)
3 months**		1.35	%		-4.47	%		1.18	%		-3.82	%		1.16	%		0.16	%		1.47	%
Year to date**		7.00	%		0.86	%		6.63	%		1.63	%		6.59	%		5.59	%		7.22	%
1 year		38.98	%		31.01	%		38.13	%		33.13	%		37.93	%		36.93	%		NA
5 years		5.88	%		4.63	%		5.21	%		4.89	%		5.04	%		5.04	%		NA
10 years		8.80	%		8.16	%		8.09	%		8.09	%		7.99	%		7.99	%		NA
Life of fund		9.77	%		9.17	%		9.07	%		9.07	%		8.96	%		8.96	%		24.30	%**
Columbia Acorn International (10/16/00)
3 months**		1.61	%		-4.22	%		1.43	%		-3.52	%		1.40	%		0.41	%		1.69	%
Year to date**		2.86	%		-3.05	%		2.52	%		-2.48	%		2.45	%		1.45	%		3.06	%
1 year		31.78	%		24.19	%		31.02	%		26.02	%		30.78	%		29.78	%		NA
5 years		6.98	%		5.72	%		6.31	%		6.00	%		6.14	%		6.14	%		NA
10 years		10.87	%		10.21	%		10.14	%		10.14	%		10.05	%		10.05	%		NA
Life of fund		8.05	%		7.45	%		7.35	%		7.35	%		7.26	%		7.26	%		12.85	%**
Columbia Acorn USA (10/16/00)
3 months**		1.42	%		-4.43	%		1.24	%		-3.76	%		1.25	%		0.25	%		1.50	%
Year to date**		8.97	%		2.70	%		8.55	%		3.55	%		8.59	%		7.59	%		9.17	%
1 year		42.90	%		34.69	%		42.00	%		37.00	%		41.82	%		40.82	%		NA
5 years		4.55	%		3.32	%		3.86	%		3.52	%		3.73	%		3.73	%		NA
10 years		6.79	%		6.16	%		6.08	%		6.08	%		5.99	%		5.99	%		NA
Life of fund		9.37	%		8.77	%		8.65	%		8.65	%		8.58	%		8.58	%		28.63	%**
Columbia Acorn International Select (10/16/00)
3 months**		1.02	%		-4.78	%		0.83	%		-4.17	%		0.81	%		-0.19	%		1.15	%
Year to date**		3.55	%		-2.41	%		3.21	%		-1.79	%		3.12	%		2.12	%		3.83	%
1 year		30.82	%		23.31	%		29.90	%		24.90	%		29.78	%		28.78	%		NA
5 years		6.85	%		5.59	%		6.15	%		5.83	%		5.99	%		5.99	%		NA
10 years		9.13	%		8.48	%		8.41	%		8.41	%		8.31	%		8.31	%		NA
Life of fund		5.88	%		5.30	%		5.18	%		5.18	%		5.09	%		5.09	%		12.66	%**
Columbia Acorn Select (10/16/00)
3 months**		-1.01	%		-6.70	%		-1.18	%		-6.07	%		-1.22	%		-2.20	%		-0.93	%
Year to date**		-0.12	%		-5.85	%		-0.46	%		-5.39	%		-0.53	%		-1.52	%		0.04	%
1 year		28.66	%		21.28	%		27.85	%		22.85	%		27.63	%		26.63	%		NA
5 years		4.86	%		3.63	%		4.18	%		3.84	%		4.02	%		4.02	%		NA
10 years		8.05	%		7.42	%		7.33	%		7.33	%		7.23	%		7.23	%		NA
Life of fund		8.46	%		7.86	%		7.74	%		7.74	%		7.64	%		7.64	%		16.21	%**
Columbia Thermostat Fund (3/3/03)†
3 months**		1.38	%		-4.44	%		1.31	%		-3.69	%		1.25	%		0.25	%		—
Year to date**		4.44	%		-1.58	%		4.28	%		-0.72	%		4.06	%		3.06	%
1 year		25.05	%		17.89	%		24.35	%		19.35	%		24.00	%		23.00	%		—
5 years		5.54	%		4.31	%		5.01	%		4.68	%		4.74	%		4.74	%		—
Life of fund		7.95	%		7.18	%		7.35	%		7.35	%		7.15	%		7.15	%		—

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

**Not annualized.

†Class I shares commenced operations on September 27, 2010. This share class is offered at net asset value without sales charge and is available only to qualifying institutional investors.

Performance data shown represents past performance and is not a guarantee of future results. The investment return and principal value of an investment will fluctuate so that 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 adviser and/or any of its affiliates. Absent these fee waivers and/or expense reimbursement arrangements, performance results would have been lower. Current performance may be lower or higher than the performance data shown. Please visit columbiamanagement.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%, 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: 1.07%; Class B: 1.69%; Class C: 1.85%; Class I: 0.72%. Columbia Acorn International: Class A: 1.35%; Class B: 1.96%; Class C: 2.11%; Class I: 0.93%. Columbia Acorn USA: Class A: 1.30%; Class B: 1.98%; Class C: 2.08%; Class I: 0.95%. Columbia Acorn International Select: Class A: 1.56%; Class B: 2.24%; Class C: 2.36%; Class I: 1.13%. Columbia Acorn Select: Class A: 1.28%; Class B: 1.93%; Class C: 2.08%; Class I: 0.92%. Columbia Thermostat Fund has a contractual expense waiver or reimbursement that expires April 30, 2012. 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: 1.52%, 1.29%; Class B: 2.07%, 1.79%; Class C: 2.28%, 2.04%, respectively.

††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 6/30/11

Class A Shares, without sales charge	2nd quarter*			Year to date*			1 year			3 years			5 years			10 years			Life of Fund
Columbia Acorn Fund (LACAX) (10/16/00)		1.35	%		7.00	%		38.98	%		8.09	%		5.88	%		8.80	%		9.77	%
Russell 2500 Index		-0.59	%		8.06	%		39.28	%		8.17	%		5.20	%		7.40	%		7.60	%
S&P 500 Index**		0.10	%		6.02	%		30.69	%		3.34	%		2.94	%		2.72	%		1.52	%
Lipper Small-Cap Core Funds Index		-1.36	%		6.18	%		36.32	%		7.54	%		4.74	%		6.91	%		7.30	%
Lipper Mid-Cap Growth Funds Index		-0.04	%		7.57	%		39.76	%		5.63	%		6.86	%		4.73	%		1.67	%
Columbia Acorn International (LAIAX) (10/16/00)		1.61	%		2.86	%		31.78	%		3.84	%		6.98	%		10.87	%		8.05	%
S&P Global Ex-U.S. Between $500 Million and $5 Billion Index		0.72	%		2.63	%		34.29	%		5.43	%		7.09	%		12.71	%		11.09	%
S&P Global Ex-U.S. SmallCap Index		0.59	%		3.62	%		35.68	%		4.10	%		5.91	%		11.92	%		10.24	%
MSCI EAFE Index (Net)		1.56	%		4.98	%		30.36	%		-1.77	%		1.48	%		5.66	%		3.85	%
Lipper International Small/Mid Growth Funds Index		1.69	%		2.88	%		36.54	%		2.35	%		4.85	%		9.71	%		6.64	%
Columbia Acorn USA (LAUAX) (10/16/00)		1.42	%		8.97	%		42.90	%		7.78	%		4.55	%		6.79	%		9.37	%
Russell 2000 Index		-1.61	%		6.21	%		37.41	%		7.77	%		4.08	%		6.27	%		6.59	%
Russell 2500 Index		-0.59	%		8.06	%		39.28	%		8.17	%		5.20	%		7.40	%		7.60	%
S&P 500 Index**		0.10	%		6.02	%		30.69	%		3.34	%		2.94	%		2.72	%		1.52	%
Lipper Small-Cap Growth Funds Index		0.23	%		9.07	%		41.91	%		7.60	%		4.77	%		4.04	%		2.45	%
Columbia Acorn Int'l Select (LAFAX) (10/16/00)		1.02	%		3.55	%		30.82	%		-0.65	%		6.85	%		9.13	%		5.88	%
S&P Developed Ex-U.S. Between $2 Billion and $10 Billion Index		0.90	%		4.04	%		33.74	%		1.73	%		3.73	%		9.60	%		8.38	%
MSCI EAFE Index (Net)		1.56	%		4.98	%		30.36	%		-1.77	%		1.48	%		5.66	%		3.85	%
Lipper International Small/Mid Growth Funds Index		1.69	%		2.88	%		36.54	%		2.35	%		4.85	%		9.71	%		6.64	%
Columbia Acorn Select (LTFAX) (10/16/00)		-1.01	%		-0.12	%		28.66	%		2.98	%		4.86	%		8.05	%		8.46	%
S&P MidCap 400 Index		-0.73	%		8.56	%		39.38	%		7.82	%		6.60	%		7.94	%		7.82	%
S&P 500 Index**		0.10	%		6.02	%		30.69	%		3.34	%		2.94	%		2.72	%		1.52	%
Lipper Mid-Cap Growth Funds Index		-0.04	%		7.57	%		39.76	%		5.63	%		6.86	%		4.73	%		1.67	%
Columbia Thermostat Fund (CTFAX) (3/3/03)†		1.38	%		4.44	%		25.05	%		5.54	%		5.54	%		—			7.95	%
S&P 500 Index		0.10	%		6.02	%		30.69	%		3.34	%		2.94	%		—			7.68	%
Barclays Capital U.S. Aggregate Bond Index		2.29	%		2.72	%		3.90	%		6.46	%		6.52	%		—			4.93	%
Lipper Flexible Portfolio Funds Index		0.46	%		5.11	%		23.38	%		4.00	%		5.16	%		—			8.35	%
50/50 Blended Benchmark††		1.21	%		4.40	%		16.88	%		5.45	%		5.14	%		—			6.60	%

*Not annualized.

**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.

Performance data shown represents past performance and is not a guarantee of future results. The investment return and principal value of an investment will fluctuate so that shares, when redeemed, may be worth more or less than their original cost. Current performance may be lower or higher than the performance data shown. Please visit columbiamanagement.com for daily and most recent month-end updates.

Performance results reflect any fee waivers or reimbursements of Fund expenses by the investment adviser 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 stated as of 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: 1.07%; Class B: 1.69%; Class C: 1.85%, Class I: 0.72%. Columbia Acorn International: Class A: 1.35%; Class B: 1.96%; Class C: 2.11%, Class I: 0.93%. Columbia Acorn USA: Class A: 1.30%; Class B: 1.98%; Class C: 2.08% Class I: 0.95%. Columbia Acorn International Select: Class A: 1.56%; Class B: 2.24%; Class C: 2.36% Class I: 1.13%. Columbia Acorn Select: Class A: 1.28%; Class B: 1.93%; Class C: 2.08%, Class I: 0.92%. Columbia Thermostat Fund has a contractual expense waiver or reimbursement that expires April 30, 2012. 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: 1.52%, 1.29%; Class B: 2.07%, 1.79%; Class C: 2.28%, 2.04%, respectively.

†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 adviser.

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.

2

Columbia Acorn Family of Funds

Descriptions of Indexes Included in this Report

•50/50 Blended Benchmark, established by the Fund's adviser, 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, including Columbia Acorn Fund and Columbia Acorn Select; Lipper International Small/Mid Growth Funds Index, 10 largest non-U.S. small/mid growth funds, including Columbia Acorn International; Lipper Small-Cap Growth Funds Index, 30 largest small-cap growth funds, including Columbia Acorn USA; 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 (Net) is a capitalization-weighted index that tracks the total return of common stocks in 22 developed-market countries within Europe, Australasia and the Far East. The returns of the MSCI EAFE Index (Net) are presented net of the withholding tax rate applicable to foreign non-resident institutional investors in the foreign companies included in the index who do not benefit from double taxation treaties.

•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 $2B and $10B 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 consists of the bottom 20% of institutionally investable capital of developed and emerging countries, outside the United States.

•S&P Global Ex-U.S. Between $500M and $5B 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: Shale Gas Returns, Transforming the Energy Outlook

Just five to seven years ago, it was widely believed that North American natural gas resources were being rapidly depleted. Today, the outlook appears to be very much improved thanks to the ingenuity of a few individuals and a process that should provide natural gas for decades to come.

In 1825, some 34 years before Colonel Edwin Drake¹ drilled the first oil well in Titusville, Pennsylvania, William Aaron Hart drilled the first natural gas well, in shale located in Fredonia, New York. By August of that year, five structures in the village were illuminated by natural gas and by November there were 36 gas lights in the village. In 1857, Preston Barmore, the superintendent of the Fredonia Natural Gas Co., was not satisfied with the production from a 122 foot well so he exploded crevices of rock in the well, increasing the supply of gas. Within a few years, the village had 150 gas lights.²

Plenty of natural gas was subsequently found in sandstone formations under impermeable rock, in similar formations as oil, or accompanied by oil. Extracting this natural gas was less costly than drilling for gas in shale, so shale exploration all but ended. Over 300,000 miles of gas pipelines were built, and demand for natural gas grew.³ U.S.-marketed production rose to 1 trillion cubic feet (TCF) of natural gas by 1923, and has ranged from 16.9 to 22.6 TCF since 1973.⁴ Natural gas is used for heating and manufacturing, and is a feedstock for fertilizers, plastics and chemicals.

Recent Natural Gas Shortages

In 2004, Julian Darley wrote High Noon for Natural Gas, The New Energy Crisis. He reviewed Hubbert's Peak, a theory named after the geologist who researched oil finding and production curves and then correctly predicted that U.S. oil production would peak around 1970. Darley applied Hubbert's Peak to natural gas data and concluded that North American gas production had also peaked and was likely to plunge.

Darley wrote, "The United States and Canada are entering a natural gas crisis ...North American supply is simply no longer able to meet desired consumption."⁵ He added, "...the worst immediate problem confronting the United States (and Canada) is not oil, but natural gas. It is a natural gas shortage that could seriously interrupt the U.S. economy..."⁶ Darley noted that the U.S. Energy Information Administration (EIA) made enormous upward revisions for production of natural gas from shale, tight sands and coal beds, but he believed such gains would fail to occur. Instead, importing of liquefied natural gas (LNG) would have to be an interim solution. But LNG, Darley stated, had safety and security risks. Geopolitically, relying on imported LNG would also be problematic, as Russia and Iran had the largest reserves of natural gas.

Darley believed that the 300-plus new natural gas-fired electric generating stations, built between 1980 and 2003 at a cost of $100 billion, were huge mistakes. The power companies had apparently reviewed a 1999 National Petroleum Council report that stated North American natural gas supplies would grow. Darley labeled that report as an "example of the kind of cornucopian delusion that characterizes many in government and most in industry, who believe in nothing but economics and the miracle of capitalism with its unlimited ability to find substitutes for everything."⁷

Darley thought that with worldwide Peak Oil imminent and North American natural gas production plunging, energy was to become scarce, and the industrial revolution would unwind. He advocated that people should be able to obtain their daily needs within walking distance from where they lived. His long-term solution was to depopulate the earth, such that mankind no longer mined the planet and consumed only the energy that the sun regularly provides. At one child per woman, the population of the earth would be back to one billion in about one hundred years.

Domestic natural gas production fell between 2001 and 2005 and prices increased between 2002 and 2008.⁸ Most major oil companies and analysts agreed that natural gas production in North America was peaking, and that the U.S. would need substantial imports of LNG. I remember going to an energy conference in early 2006 where this view was widespread. Darley's nightmare scenario seemed to be coming true.

4

Back in the Gas Fields

George Mitchell has been called the Father of the Barnett Natural Gas Field, located in and around Fort Worth, Texas. Over an 18-year period beginning in 1981, his company, Mitchell Energy and Development, experimented with fracturing gas-bearing shale that is located between 6,000 and 14,000 feet below the surface. Geologists knew that shale had lots of pores and the ability to store natural gas, but since pores in shale are rarely interconnected, gas flows poorly through shale. Initial attempts to extract this gas were costly, and production was not economical. Eventually, the company developed a "light sand frac" method that was effective and used less fluid. The combination of reduced costs and rising natural gas prices made such drilling profitable. Mitchell drilled many wells at the Barnett field, producing far more natural gas than most people expected.⁹

Mitchell needed more funding and sold his company to Devon Energy, a larger, independent producer. Devon had expertise in an additional technology, horizontal drilling, which tilted drill holes at angles or sideways once they hit pay dirt. More gas-bearing shale was consequently exposed to the well. With this added technology, the company drilled 55 wells in the Barnett field in 2003 and the shale gas boom began.¹⁰ Some 13,500 gas wells have been drilled in the Barnett field since 1997¹¹ and the Barnett field accounted for 6% of total natural gas production in the United States in 2010.¹²

Drilling at other shale gas formations has also jumped. U.S. shale gas production increased 12-fold in the last decade and currently accounts for about 25% of U.S. natural gas production.¹³ With greater production, natural gas wellhead prices halved from 2008 to 2010. In its yearly forecast in 2010, the EIA doubled its estimate of U.S. shale gas production for 2035 and predicts shale gas production will hit 46% of U.S. consumption that year.¹⁴ Imports will drop from 11% of natural gas consumption in 2009 to 1%.¹⁵ With "economics and the miracle of capitalism,"¹⁶ we won't need to revert to Darley's dark ages any time soon. The EIA also believes shale gas totaling at least six-times U.S. reserves is recoverable in at least 32 other countries.¹⁷

Energy Mix

In 2009, Robert Hefner published The Grand Energy Transition. The book provides perspectives on past and future sources and uses of energy. Hefner believes that energy usage naturally transitions from solids (wood and coal) to liquids (oil) and then to gasses (natural gas, wind and hopefully nuclear fusion). He sees newer fuels as superior to older ones, with each new fuel facilitating new technologies, improvements in the environment and higher living standards.

The transition to coal from wood powered the industrial revolution and allowed millions of acres of forests to regrow. Coal then fell from 80% of the world energy market in 1900 to about 28% currently. Oil ascended to 48% of the world's energy by 1973, displacing much dirty coal and revolutionizing transportation via the introduction of automobiles and airplanes. Oil subsequently dropped to about 36% of world energy consumption. Natural gas has risen from 10% of the world's energy in 1950 to 24% currently.¹⁸

Believing in global warming, Hefner notes that the transition from wood to coal to oil to natural gas slashed carbon content and increased hydrogen content of fuels with each transition. Since burning carbon creates carbon dioxide (CO₂), the primary greenhouse gas, and burning hydrogen creates water, the natural transitions from solids to liquids to gasses slow global warming. Burning natural gas creates 44% less CO₂ than burning coal and 29% less than burning oil. Burning natural gas also emits about 80% less nitrogen oxides, over 90% lower particulates and over 99% less sulfur dioxide than coal or oil.¹⁹

Under an earlier belief that the United States was running out of natural gas, the Natural Gas Policy Act (NGPA) and the Fuel Use Act were passed in 1978. The NGPA immediately deregulated prices for gas produced from deep wells and phased out other price controls.²⁰ The Fuel Use Act mandated the phase out of natural gas for electric generation and restricted its industrial uses. Prices for deep gas jumped, but so did drilling. Production grew, and with demand depressed by the Fuel Use Act, prices then collapsed. There was an excess supply of natural gas, known as the "gas bubble," until the year 2000.

Hefner believes that prior price controls and the Fuel Use Act slowed the natural transition from coal and oil to natural gas. As a result of the Fuel Use Act, some 100,000 megawatts of coal-fired electric generating capacity was built in the United States through 1989 that has emitted 15 billion metric tons of CO₂ into the atmosphere.²¹ Hefner

5

believes that the construction of the coal burning plants, not the natural gas burning plants, was the big mistake.

Hefner subscribes to Peak Oil occurring soon, but sees many decades of abundant and relatively cheap natural gas. Hence, he predicts the grand energy transition to natural gas will continue, and he believes natural gas will be a bridge fuel to renewable energy and possibly nuclear fusion. Natural gas complements wind energy quite well, as gas-burning electric plants can quickly power up when the wind slows.

Some 12 million vehicles worldwide are powered by natural gas. Of that number, there are estimated to be 110,000 natural gas-powered vehicles in the United States,²² including thousands of trucks serving the ports of Long Beach and Los Angeles,²³ more than 11,000 buses²⁴ and approximately 12,000 Honda Civic GX cars.²⁵ These vehicles burn natural gas currently priced at one-third of the energy equivalent price of oil. Hefner believes that half the autos in the United States should be powered by natural gas, and the dirtiest, coal-burning electric plants should be replaced by natural gas plants. Yearly gas consumption would rise by 13 TCF, but could be met by increased shale gas production.²⁶

Investment Implications

We believe that innovations in producing gas from shale have indeed transformed the U.S. energy outlook. We profitably invested in some of the pioneers of shale gas though, with the current glut of natural gas, the stocks now look less attractive. Supplies of gas may remain high in the short term as some unprofitable drilling persists in order to keep lease rights. Over time, the low prices will likely result in reduced drilling and more constrained supplies. When this happens, natural gas prices should rise to a level where drilling and production are moderately profitable. We continue to look for suppliers and service companies participating in shale gas production. Some shale oil fields are now being developed, including the Bakken field in North Dakota and Canada and the Eagle Ford field in Texas. At this point, we don't think there will be enough shale oil production to revolutionize the oil market, but we do believe we have found some attractive stocks participating in those developments.

Charles P. McQuaid

President and Chief Investment Officer
Columbia Wanger Asset Management, LLC

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 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 behalf of any particular Columbia Acorn Fund.

¹  Colonel Edwin Drake was an American oil driller, credited with being the first to drill for oil in the United States.

²  Lash, Eileen and Gary, "The Early History of Natural Gas, Kicking Down the Well," The SUNY Fredonia Shale Research Institute, June 3, 2011, http://www.fredonia.edu/shaleinstitute/history.asp.

³  U.S. Energy Information Administration (EIA), http://www.eia.gov/pub/oil_gas/natural_gas/analysis_publications/ngpipeline/index.html.

⁴  EIA data, including imports primarily from Canada, states the U.S. has been using about 23 trillion cubic feet (TCF) of gas a year, including about 6.6 TCF for industrial purposes. www.eia.gov.

⁵  Darley, Julian, High Noon for Natural Gas, The New Energy Crisis, (White River Junction, Vermont, Chelsea Green Publishing Company 2004) p. 13.

⁶  Ibid., p. 2.

⁷  Ibid., p. 79-80.

⁸  According to EIA data, domestic natural gas production fell from 20.6 TCF in 2001 to 18.9 TCF in 2005. Average annual wellhead prices rose from $3 to $5 in 2002-2003 to $6 to $8 from 2006-2008. www.eia.gov.

⁹  Airhart, Marc, "The Father of the Barnett Natural Gas Field," http://geology.com/research/barnett-shale-father.html.

¹⁰  Yergin, Daniel, "Stepping on the Gas," Wall Street Journal, April 2, 2011.

¹¹  Presentation for the Organization of Economic Cooperation and Development (OECD), "Shale Gas and the Outlook for U.S. Natural Gas Markets and Global Gas Resources," June 21, 2011, http://www.eia.gov/pressroom/presentations/newell_06212011.pdf.

¹²  U.S. Department of Energy, Office of Fossil Energy and National Energy Technology Laboratory, "Modern Shale Gas, Development in the United States: A Primer," April 2009, p. ES-1, http://fossil.energy.gov/programs/oilgas/publications/
naturalgas_general/Shale_Gas_Primer_2009.pdf

¹³  Presentation for the Organization of Economic Cooperation and Development (OECD), "Shale Gas and the Outlook for U.S. Natural Gas Markets and Global Gas Resources," June 21, 2011, http://www.eia.gov/pressroom/presentations/newell_06212011.pdf.

6

¹⁴  Lomax, Simon, "Shale-Gas Output May Double by 2035, Reducing Energy Imports, U.S. Says," Bloomberg, December 16, 2010, http://www.bloomberg.com/news/2010-12-16/natural-gas-production-from-shale-may-double-by-35-u-s-agency-forecasts.html.

¹⁵  Presentation for the Organization of Economic Cooperation and Development (OECD), "Shale Gas and the Outlook for U.S. Natural Gas Markets and Global Gas Resources," June 21, 2011, http://www.eia.gov/pressroom/presentations/newell_06212011.pdf.

¹⁶  Darley, Julian, op. cit., p. 79-80.

¹⁷  Presentation for the Organization of Economic Cooperation and Development (OECD), "Shale Gas and the Outlook for U.S. Natural Gas Markets and Global Gas Resources," June 21, 2011, http://www.eia.gov/pressroom/presentations/newell_06212011.pdf.

¹⁸  Hefner III, Robert A., The Grand Energy Transition, (Hoboken, New Jersey, John Wiley & Sons, Inc. 2009) p. 27.

¹⁹  U.S. Department of Energy, Office of Fossil Energy and National Energy Technology Laboratory, "Modern Shale Gas, Development in the United States: A Primer," April 2009, p. 5, http://fossil.energy.gov/programs/oilgas/publications/naturalgas_general/Shale_
Gas_Primer_2009.pdf

²⁰  Hefner III, Robert A., op. cit., p. 120-121. Having been an independent explorer for natural gas, Hefner was well aware that gas existed in locations independently of oil. (He has been called the "Father of Deep Natural Gas" as his company drilled very deep wells finding only natural gas at very high pressure.) In the 1970s when geologists for major oil companies testified to Congress that the U.S. was running out of natural gas, Hefner dissented, believing that the shortage was caused by price controls in place since 1954. Price controls cause shortages of valuable commodities by boosting demand and restraining supplies.

²¹  Ibid., p. 122.

²²  Natural Gas Vehicles of America, http://www.ngvc.org/mktplace/index.html. Accessed July 20, 2011.

²³  Hefner III, Robert A., op. cit., p. 201.

²⁴  Natural Gas Vehicles of America, http://www.ngvc.org/mktplace/index.html. Accessed July 20, 2011.

²⁵  Oberman, Mira, "The Greenest Car You've (Likely) Never Heard Of," Agence France-Presse, April 11, 2011.

²⁶  Hefner III, Robert A., op. cit., p. 203.

7

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, C and I 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.

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 Investment Services Corp., your account balance is available online at columbiamanagement.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.

8

January 1, 2011 – June 30, 2011

	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		1,070.00		1,019.59		5.39		5.26		1.05
Class B		1,000.00		1,000.00		1,066.30		1,016.12		8.97		8.75		1.75
Class C		1,000.00		1,000.00		1,065.90		1,015.72		9.37		9.15		1.83
Class I**		1,000.00		1,000.00		1,072.20		1,021.22		3.70		3.61		0.72
Columbia Acorn International
Class A		1,000.00		1,000.00		1,028.60		1,018.40		6.49		6.46		1.29
Class B		1,000.00		1,000.00		1,025.20		1,015.08		9.84		9.79		1.96
Class C		1,000.00		1,000.00		1,024.50		1,014.58		10.34		10.29		2.06
Class I**		1,000.00		1,000.00		1,030.60		1,020.33		4.53		4.51		0.90
Columbia Acorn USA
Class A		1,000.00		1,000.00		1,089.70		1,018.45		6.63		6.41		1.28
Class B		1,000.00		1,000.00		1,085.50		1,014.73		10.50		10.14		2.03
Class C		1,000.00		1,000.00		1,085.90		1,014.63		10.60		10.24		2.05
Class I**		1,000.00		1,000.00		1,091.70		1,020.13		4.88		4.71		0.94
Columbia Acorn International Select
Class A		1,000.00		1,000.00		1,035.50		1,017.26		7.67		7.60		1.52
Class B†		1,000.00		1,000.00		1,032.10		1,013.88		11.08		10.99		2.20
Class C		1,000.00		1,000.00		1,031.20		1,013.24		11.73		11.63		2.33
Class I**		1,000.00		1,000.00		1,038.30		1,019.84		5.05		5.01		1.00
Columbia Acorn Select
Class A		1,000.00		1,000.00		998.80		1,018.55		6.24		6.31		1.26
Class B		1,000.00		1,000.00		995.40		1,015.22		9.55		9.64		1.93
Class C		1,000.00		1,000.00		994.70		1,014.58		10.19		10.29		2.06
Class I**		1,000.00		1,000.00		1,000.40		1,020.28		4.51		4.56		0.91
Columbia Thermostat Fund***
Class A		1,000.00		1,000.00		1,044.40		1,022.32		2.53		2.51		0.50
Class B		1,000.00		1,000.00		1,042.80		1,019.84		5.07		5.01		1.00
Class C		1,000.00		1,000.00		1,040.60		1,018.60		6.32		6.26		1.25

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, 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.

*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.

**Class I shares were initially offered by the Funds on September 27, 2010.

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

†Had the investment adviser 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. See the Notes to Financial Statements for more information about expense limits.

9

Columbia Acorn Fund

In a Nutshell

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

Performance data shown represents past performance and is not a 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. Current performance may be lower or higher than the performance data shown. Please visit columbiamanagement.com for daily and most recent month-end performance updates.

Fund Positions
in Mentioned Holdings

As a percentage of net assets, as of 6/30/11

lululemon athletica	2.3	%
Informatica	1.4	%
Abercrombie & Fitch	1.2	%
IPG Photonics	1.0	%
Fugro	1.0	%
Polycom	0.8	%
Hansen Natural	0.8	%
Pacific Rubiales Energy	0.7	%
Oshkosh	0.5	%
SRA International	0.3	%

Columbia Acorn Fund rose 1.35% (Class A shares, without sales charge) in the second quarter of 2011, outperforming the 0.59% drop in its primary benchmark, the Russell 2500 Index, and also beating other indexes shown on Page 2. During the first half of 2011, the Fund was up 7.00%, somewhat less than the Russell 2500's gain of 8.06%, and was mixed versus other indexes.

Consumer stocks were marked up during both the quarter and the half. Premium active apparel retailer lululemon athletica was the Fund's top dollar winner during both periods, up 26% in the quarter and 63% in the half. Alternative beverage producer Hansen Natural also provided large gains, rising 34% in the quarter and 55% in the half. Sales momentum at teen apparel retailer Abercrombie & Fitch accelerated, causing its stock to rack up a 14% gain in the quarter and a 16% gain in the half. All three companies had excellent growth in sales and earnings.

Several technology stocks also boosted results for the Fund. IPG Photonics, a company that is coupling laser and fiber optic technology, was Columbia Acorn Fund's second largest dollar gainer in both the quarter and the half, rising 26% and 130%, respectively. The company's quarterly earnings per share grew over six-fold on revenues that nearly doubled versus the prior year. Data integration software company Informatica rose 12% in the quarter and 33% in the half on fine earnings growth. Video conferencing equipment maker Polycom showed a 24% gain in the quarter and a 65% jump in the half on better than expected earnings.

Performance was boosted by takeovers. In the quarter, device maker American Medical Systems appreciated 39% as it agreed to be taken over by Endo Pharmaceuticals. Government I.T. services company SRA International agreed to sell out to a private equity firm, and its stock was up 51% in the half. GSI Commerce and Terremark were subject to takeover offers in the first quarter and their stocks also helped first half results.

The Fund's largest dollar loser in the quarter was sub-sea oilfield services provider Fugro, off 16% on disappointing earnings caused by customers delaying projects. Oshkosh fell 18% in the quarter, on news of a difficult start to military truck production. The Fund's largest dollar loser in the half was Colombian oil producer Pacific Rubiales Energy, off 21%. The stock gave up a fraction of its 2010 gains on exploration results that disappointed some analysts.

Columbia Acorn Fund's foreign stocks were off 3.59% in the quarter and 2.69% in the half.* Fugro and Pacific Rubiales Energy, mentioned above, were the largest foreign losers. The Fund's international stock weight dropped to 10.8% from 11.6% at the end of the first quarter and from 12.6% at the end of 2010.

The markets have been concerned about sovereign debt issues. While the U.S. debt ceiling was raised after the end of the quarter, the debt deal resulted in no fundamental reforms and large remaining uncertainties. A congressional committee will hopefully provide better solutions on schedule, before the end of 2011. The Greek debt situation seems more intractable, but the size of the debt is relatively small. Meanwhile, most of the companies owned by the Fund have been reporting fine earnings gains, which we believe could lead to higher stock prices should macroeconomic concerns ease.

*These returns are not comparable to mutual fund returns, as they are gross of fees and other expenses and do not portray the cash effects incurred by actual mutual funds. Columbia Acorn Fund's foreign stockholdings were not purchased as a balanced, stand-alone portfolio.

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.

10

Columbia Acorn Fund

At a Glance (Class A Shares - LACAX)

Performance data shown represents past performance and is not a guarantee of future results. The investment return and principal value of an investment will fluctuate so that shares, when redeemed, may be worth more or less than their original cost. Current performance may be lower or higher than the performance data shown. Performance results reflect any fee waivers or reimbursements of Fund expenses by the investment adviser and/or any of its affiliates. Absent these fee waivers and/or expense reimbursement arrangements, performance results would have been lower. Please visit columbiamanagement.com for daily and most recent month-end updates.

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

through June 30, 2011

Inception 10/16/00		Year to date*			1 year			5 years			10 years
Returns before taxes	NAV POP		7.00 0.86	%		38.98 31.01	%		5.88 4.63	%		8.80 8.16	%
Returns after taxes on distributions	NAV POP		6.81 0.68			38.15 30.22			5.21 3.97			8.28 7.64
Returns after taxes on distributions and sale of fund shares	NAV POP		4.75 0.75			26.29 21.05			4.98 3.89			7.72 7.13
Russell 2500 Index**(pretax)			8.06			39.28			5.20			7.40

All results shown assume reinvestment of distributions.

*Year to date data is not annualized.

**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.

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 1.07%.

Columbia Acorn Fund Portfolio Diversification

as a percentage of net assets, as of 6/30/11

Columbia Acorn Fund Top 10 Holdings

as a percentage of net assets, as of 6/30/11

1.	lululemon athletica Premium Active Apparel Retailer	2.3	%
2.	Ametek Aerospace/Industrial Instruments	1.6	%
3.	FMC Technologies Oil & Gas Wellhead Manufacturer	1.4	%
4.	Informatica Enterprise Data Integration Software	1.4	%
5.	Mettler Toledo Laboratory Equipment	1.4	%
6.	Donaldson Industrial Air Filtration	1.3	%
7.	Crown Castle International Communications Towers	1.3	%
8.	Abercrombie & Fitch Teen Apparel Retailer	1.2	%
9.	IPG Photonics Fiber Lasers	1.1	%
10.	Alexion Pharmaceuticals Biotech Focused on Orphan Diseases	1.0	%

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 Fund (Class A)

October 16, 2000 through June 30, 2011

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 may pay on Fund distributions or on a sale of Fund shares.

Total Net Assets of the Fund: $19.3 billion

†  Class I shares commenced operations on September 27, 2010.

11

Columbia Acorn International

In a Nutshell

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

Performance data shown represents past performance and is not a 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. Current performance may be lower or higher than the performance data shown. Please visit columbiamanagement.com for daily and most recent month-end performance updates.

Fund's Positions
in Mentioned Holdings

As a percentage of net assets, as of 6/30/11

Melco Crown Entertainment	1.4	%
ShawCor	0.8	%
Simplo Technology	0.7	%
President Chain Store	0.5	%
Gree	0.5	%
Start Today	0.4	%
Petropavlovsk	0.4	%

Columbia Acorn International was up 1.61% (Class A shares, without sales charge) in the second quarter of 2011, 0.89% ahead of its primary benchmark, the S&P Global Ex-U.S. Between $500M and $5B Index. This brought the Fund's return for the six months to 2.86%, slightly ahead of the 2.63% gain of its benchmark.

The Fund's absolute returns in the quarter were highest in Asia, driven by Melco Crown Entertainment, which operates a casino in Macau; Simplo Technology, a Taiwanese manufacturer of battery packs for notebook computers and iPads; and President Chain Store, a Taiwanese convenience store operator with inroads into mainland China. Consistent with the performance of these stocks, consumer discretionary and information technology sector holdings were the Fund's best performing globally. In a somewhat subdued quarter for international small-cap stocks overall, the Fund's Japanese holdings also put up a pleasing 5.9% USD return, led by two of the Fund's internet-related stocks: Gree, a social networking site and game developer, and Start Today, an online apparel retailer. These stocks were up 32% and 29%, respectively, likely buoyed by high valuations assigned to U.S. internet-related businesses in recent public and private market transactions.

Energy and resource companies were among the most disappointing in the quarter. ShawCor was a big position and down 18% after reporting first quarter results substantially below expectations. This Canadian company makes money by coating pipelines, and the most profitable work tends to be large offshore projects, and those in Asia, the Middle East, and the North Sea. While the company is bidding on many new projects now, in recent quarters they unfortunately ran into a lull in large projects as work lined up two or three years ago came to an end. Petropavlovsk, a UK-domiciled gold and iron ore miner with mines in Russia, was off over 26% on investor worries that more delays and capital would be required to complete the company's projects. This came on top of general weakness among gold mining stocks.

Eurozone sovereign risk has recently been leading headlines. Europe, including countries not part of the common euro currency, is home to almost 40% of the Fund's assets. This is an overweight position, with risk mitigated and opportunity enhanced, we believe, by the fact that many of these European holdings have significant revenues and earnings outside of Europe. While we are not economists and do not structure the portfolio according to macroeconomic precepts, we expect the euro to survive the present crisis. We believe the protracted public debate reflects the inevitably messy process of allocating economic and political pain among creditor and debtor countries, and private and public actors. Indeed, creditor countries who seek tighter fiscal coordination among eurozone countries going forward have little to gain in ending the crisis until they have extracted such concessions. Markets, however, do not like uncertainty and continued volatility is likely until a solution is reached.

Thank you for your continued confidence in Columbia Acorn International.

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. 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.

12

Columbia Acorn International

At a Glance (Class A Shares - LAIAX)

Performance data shown represents past performance and is not a guarantee of future results. The investment return and principal value of an investment will fluctuate so that shares, when redeemed, may be worth more or less than their original cost. Current performance may be lower or higher than the performance data shown. Performance results reflect any fee waivers or reimbursements of Fund expenses by the investment adviser and/or any of its affiliates. Absent these fee waivers and/or expense reimbursement arrangements, performance results would have been lower. Please visit columbiamanagement.com for daily and most recent month-end updates.

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

through June 30, 2011

Inception 10/16/00		Year to date*			1 year			5 years			10 years
Returns before taxes	NAV POP		2.86 -3.05	%		31.78 24.19	%		6.98 5.72	%		10.87 10.21	%
Returns after taxes on distributions	NAV POP		1.98 -3.87			30.73 23.19			6.18 4.93			10.38 9.72
Returns after taxes on distributions and sale of fund shares	NAV POP		1.86 -1.98			20.94 15.99			5.92 4.82			9.68 9.07
S&P Global Ex-US Between $500M and $5B Index** (pretax)			2.63			34.29			7.09			12.71

All results shown assume reinvestment of distributions.

*Year to date data is not annualized.

**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.

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 1.35%.

Columbia Acorn International Portfolio Diversification

as a percentage of net assets, as of 6/30/11

Columbia Acorn International Top 10 Holdings

as a percentage of net assets, as of 6/30/11

1.	Hexagon (Sweden) Measurement Equipment & Software	1.5	%
2.	Melco Crown Entertainment (Hong Kong) Macau Casino Operator	1.4	%
3.	Olam International (Singapore) Agriculture Supply Chain Manager	1.2	%
4.	Localiza Rent A Car (Brazil) Car Rental	1.2	%
5.	Kansai Paint (Japan) Paint Producer in Japan, India, China & Southeast Asia	1.1	%
6.	Zhaojin Mining Industry (China) Gold Mining & Refining in China	1.0	%
7.	Imtech (Netherlands) Electromechanical & Information & Communications Technologies Installation & Maintenance	1.0	%
8.	Intertek Group (United Kingdom) Testing, Inspection & Certification Services	1.0	%
9.	Naspers (South Africa) Media in Africa, China, Russia & Other Emerging Markets	1.0	%
10.	Fugro (Netherlands) Sub-sea Oilfield Services	0.9	%

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 June 30, 2011

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 $500M and $5B 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 may pay on Fund distributions or on a sale of Fund shares.

Total Net Assets of the Fund: $6.4 billion

†  Class I shares commenced operations on September 27, 2010.

13

Columbia Acorn USA

In a Nutshell

Robert A. Mohn

Lead Portfolio Manager

Performance data shown represents past performance and is not a 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. Current performance may be lower or higher than the performance data shown. Please visit columbiamanagement.com for daily and most recent month-end performance updates.

Fund's Positions
in Mentioned Holdings

As a percentage of net assets, as of 6/30/11

IPG Photonics	2.6	%
lululemon athletica	2.3	%
Gaylord Entertainment	1.3	%
Polycom	1.3	%
Cepheid	0.8	%
Diamond Foods	0.8	%
Finisar	0.7	%
Ixia	0.6	%
TriQuint Semiconductor	0.6	%

The equity markets were relatively flat in the second quarter of 2011. Columbia Acorn USA gained 1.42% (Class A shares, without sales charge), outperforming its primary benchmark, the Russell 2000 Index, which dropped 1.61%. Year to date through June 30, 2011, the Fund was up 8.97%, ahead of the 6.21% gain of its benchmark.

Winners for the quarter and half year came from a variety of sectors. IPG Photonics, a fiber laser manufacturer, dominates its market niche and nearly doubled sales versus the prior year. Its stock rose 26% in the quarter and ended the first six-months of 2011 up 130%. Premium active apparel retailer lululemon athletica also had strong revenue growth on ever-increasing awareness of the brand in the United States. The stock rose 26% in the quarter, and was up 63% for the half year. Polycom, a provider of video conferencing equipment, was up 24% in the quarter and finished the half year with a 65% return. The company's business benefited from increased corporate adoption of video conferencing as well as recent stumbles by a close competitor.

Diamond Foods, a provider of nuts and snack foods, announced an agreement to purchase the Pringles brand from Procter & Gamble, a move that will transform Diamond into the second largest snack company in the world, behind Pepsi. The stock rose 37% in the quarter on the news and was up 44% for the half year. Cepheid, a provider of molecular diagnostic equipment, experienced strong sales of its automated genetic testing instruments, which helped drive its stock up 24% in the quarter and 52% for the half year.

On the downside, two names in the optical network equipment business fell due to revenue shortfalls. Finisar, a provider of optical sub-systems and components, was a big winner for the Fund last year but orders have slowed in 2011, leaving Finisar customers with excess inventory. Its stock was off 27% in the quarter and 39% for the six months. Ixia sells telecom test equipment for optical networks and also suffered from a drop in orders. The company's stock fell 19% in the quarter and 22% for the half year.

TriQuint Semiconductor, a manufacturer of radio frequency semiconductors for mobile phones and other wireless devices, disappointed as some handset manufacturers deferred new product launches, sending the company's stock down 21% in the quarter and 17% for the half year. Gaylord Entertainment, an owner of convention hotels, was hurt by a drop in the occupancy rate at its Washington DC hotel, sending the stock down 13% for the quarter and 17% for the half year.

These days, many investors are obsessing over a seeming epidemic of ominous macroeconomic troubles and their potential solutions. Scary stuff like national debt crises, Mediterranean defaults, stubbornly high unemployment, and double-dipping housing prices dominate the news. But we believe that these issues are not as relevant to our philosophy of investing. We don't subscribe to the current fetish of investing based on macroeconomic factors (commonly referred to as "risk-on, risk-off" trading). Even in volatile, uncertain times like today, plenty of individual smaller cap companies are growing faster than their peers and possess bright long-term prospects. We spend our time and effort seeking out these kinds of businesses for your Fund. We'll leave the macro-dancing to the other guys.

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.

14

Columbia Acorn USA

At a Glance (Class A Shares - LAUAX)

Performance data shown represents past performance and is not a guarantee of future results. The investment return and principal value of an investment will fluctuate so that shares, when redeemed, may be worth more or less than their original cost. Current performance may be lower or higher than the performance data shown. Performance results reflect any fee waivers or reimbursements of Fund expenses by the investment adviser and/or any of its affiliates. Absent these fee waivers and/or expense reimbursement arrangements, performance results would have been lower. Please visit columbiamanagement.com for daily and most recent month-end updates.

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

through June 30, 2011

Inception 10/16/00		Year to date*			1 year			5 years			10 years
Returns before taxes	NAV POP		8.97 2.70	%		42.90 34.69	%		4.55 3.32	%		6.79 6.16	%
Returns after taxes on distributions	NAV POP		8.97 2.70			42.90 34.69			4.19 2.97			6.49 5.86
Returns after taxes on distributions and sale of fund shares	NAV POP		5.83 1.76			27.89 22.55			3.87 2.81			5.93 5.36
Russell 2000 Index**(pretax)			6.21			37.41			4.08			6.27

All results shown assume reinvestment of distributions.

*Year to date data is not annualized.

**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.

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 1.30%.

Columbia Acorn USA Portfolio Diversification

as a percentage of net assets, as of 6/30/11

Columbia Acorn USA Top 10 Holdings

as a percentage of net assets, as of 6/30/11

1.	Informatica Enterprise Data Integration Software	3.0	%
2.	IPG Photonics Fiber Lasers	2.6	%
3.	FMC Technologies Oil & Gas Wellhead Manufacturer	2.3	%
4.	lululemon athletica Premium Active Apparel Retailer	2.3	%
5.	Ametek Aerospace/Industrial Instruments	2.2	%
6.	Nordson Dispensing Systems for Adhesives & Coatings	2.1	%
7.	Atwood Oceanics Offshore Drilling Contractor	1.9	%
8.	Micros Systems Information Systems for Hotels, Restaurants & Retailers	1.8	%
9.	tw telecom Fiber Optic Telephone/Data Services	1.7	%
10.	II-VI Laser Optics & Specialty Materials	1.7	%

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 June 30, 2011

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 may pay on Fund distributions or on a sale of Fund shares.

Total Net Assets of the Fund: $1.9 billion

†  Class I shares commenced operations on September 27, 2010.

15

Columbia Acorn International Select

In a Nutshell

Christopher J. Olson

Lead Portfolio Manager

Performance data shown represents past performance and is not a 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. Current performance may be lower or higher than the performance data shown. Please visit columbiamanagement.com for daily and most recent month-end performance updates.

Fund's Positions
in Mentioned Holdings

As a percentage of net assets, as of 6/30/11

Ascendas REIT	5.0	%
Hexagon	3.7	%
Wirecard	2.7	%
Asahi Diamond Industrial	2.4	%
Jupiter Telecommunications	2.2	%
Fugro	1.9	%
United Drug	1.9	%
Pacific Rubiales Energy	1.6	%
Jiangsu Expressway	1.4	%
Gree	1.4	%
Workspace Group	1.1	%
Quetzal Energy	0.3	%

Columbia Acorn International Select ended the second quarter up 1.02% (Class A shares, without sales charge), outperforming the 0.90% gain of its primary benchmark, the S&P Developed Ex-U.S. Between $2B and $10B Index. For the half year, the Fund was up 3.55% versus a 4.04% gain for the benchmark.

The Fund's top three contributors to performance for the quarter were Japanese stocks, as the economic situation in Japan began to stabilize and recover following the March 2011 Tohoku earthquake. Gree, a mobile social networking game developer, was up 32% in the second quarter and 78% for the half year. The company continued to benefit from new product rollouts. Asahi Diamond Industrial, a manufacturer of consumable diamond tools, was up 14% in the quarter and ended the half year with a 16% gain. Its operations were largely unaffected by the earthquake and its revenues remained strong. Jupiter Telecommunications, the largest cable service provider in Japan, had a 15% gain in the quarter on continued subscriber growth. The majority of its operations are in the Tokyo region.

Elsewhere, Ascendas REIT, an industrial property landlord in Singapore, is a large position in the Fund and was up 6% for the quarter and the half year. The company continues to report rental rate increases on strong demand for its properties and its 7% dividend yield has attracted attention in a world of low interest rates. Swedish measurement equipment manufacturer Hexagon continued its strong run, gaining 4% in the quarter and ending the half year up 16%. The company has benefited from continued revenue growth driven mainly by its exposure to emerging markets.

Year to date, German online payment processor and risk manager Wirecard was up 32%. The company is growing revenues at a 20% clip on the back of ongoing growth of e-commerce as well as the introduction of a popular prepaid cash card. Irish pharmaceutical company United Drug rose 21% as investors realized earnings had improved and the stock was very cheap. Workspace Group, a UK real estate company, was up 29% for the half year, benefiting from improving occupancy rates.

Energy stocks dominated the laggards list for the quarter and half. After many quarters of strong performance, Dutch sub-sea oilfield services provider Fugro fell more than 16% in the quarter and was off 11% for the half year. The company reported disappointing earnings, stating that many of its customers opted to delay expected projects. Quetzal Energy, an oil and gas exploration company operating in Latin America, fell 44% in the quarter and was down 37% for the half as a delay in receiving environmental approvals slowed down its drilling program. Pacific Rubiales Energy, a Colombian oil production and exploration company, was off 3% in the quarter and down 21% for the half year on disappointing results from recent explorations.

Outside the energy sector, Petropavlovsk, a UK-listed company operating gold and iron ore mines in Russia, fell 15% in the quarter and was off 24% in Columbia Acorn International Select for the half year. Delays and capital concerns, combined with weakness in gold mining stocks in general, hurt returns. We sold the Fund's position in the stock. Jiangsu Expressway, a Chinese toll road operator, fell 13% in the quarter and was off 15% for the half after the government began to crack down on toll operators who were overcharging. Jiangsu Expressway has kept its charges in line with stated policy but was down nonetheless, as the entire sector was sold off.

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. 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.

16

Columbia Acorn International Select

At a Glance (Class A Shares - LAFAX)

Performance data shown represents past performance and is not a guarantee of future results. The investment return and principal value of an investment will fluctuate so that shares, when redeemed, may be worth more or less than their original cost. Current performance may be lower or higher than the performance data shown. Performance results reflect any fee waivers or reimbursements of Fund expenses by the investment adviser and/or any of its affiliates. Absent these fee waivers and/or expense reimbursement arrangements, performance results would have been lower. Please visit columbiamanagement.com for daily and most recent month-end updates.

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

through June 30, 2011

Inception 10/16/00		Year to date*			1 year			5 years			10 years
Returns before taxes	NAV POP		3.55 -2.41	%		30.82 23.31	%		6.85 5.59	%		9.13 8.48	%
Returns after taxes on distributions	NAV POP		3.16 -2.78			30.46 22.97			6.51 5.26			8.97 8.33
Returns after taxes on distributions and sale of fund shares	NAV POP		2.31 -1.57			20.17 15.28			5.92 4.82			8.16 7.57
S&P Developed Ex-US Between $2B and $10B Index** (pretax)			4.04			33.74			3.73			9.60

All results shown assume reinvestment of distributions.

*Year to date data is not annualized.

**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.

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 1.56%.

Columbia Acorn International Select Portfolio Diversification

as a percentage of net assets, as of 6/30/11

Columbia Acorn International Select Top 10 Holdings

as a percentage of net assets, as of 6/30/11

1.	Ascendas REIT (Singapore) Singapore Industrial Property Landlord	5.0	%
2.	Kansai Paint (Japan) Paint Producer in Japan, India, China & Southeast Asia	4.4	%
3.	Chemring (United Kingdom) Defense Manufacturer of Countermeasures & Energetics	3.8	%
4.	Hexagon (Sweden) Measurement Equipment & Software	3.7	%
5.	NHN (South Korea) South Korea's Largest Online Search Engine	3.2	%
6.	Mapletree Industrial Trust (Singapore) Industrial Property Landlord	3.2	%
7.	Intertek Group (United Kingdom) Testing, Inspection & Certification Services	2.9	%
8.	Wirecard (Germany) Online Payment Processing & Risk Management	2.7	%
9.	Asahi Diamond Industrial (Japan) Consumable Diamond Tools	2.4	%
10.	AkzoNobel (Netherlands) Largest Global Supplier of Protective Paints & Coatings	2.4	%

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 June 30, 2011

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 $2B and $10B 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 may pay on Fund distributions or on a sale of Fund shares.

Total Net Assets of the Fund: $437.3 million

†  Class I shares commenced operations on September 27, 2010.

17

Columbia Acorn Select

In a Nutshell

Ben Andrews	Robert A. Chalupnik
Lead Portfolio Manager	Co-Portfolio Manager

Performance data shown represents past performance and is not a 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. Current performance may be lower or higher than the performance data shown. Please visit columbiamanagement.com for daily and most recent month-end performance updates.

Fund's Positions
in Mentioned Holdings

As a percentage of net assets, as of 6/30/11

Discover Financial Services	6.6	%
Abercrombie & Fitch	3.6	%
Coach	3.2	%
Canacol Energy	1.9	%
Quanta Services	1.4	%
Gaylord Entertainment	1.3	%
Finisar	0.3	%

Columbia Acorn Select fell 1.01% (Class A shares, without sales charge) in the second quarter of 2011 and was nearly flat for the half year, down 0.12%. The Fund's primary benchmark, the S&P MidCap 400 Index, was down 0.73% in the second quarter and up 8.56% for the six months ended June 30, 2011. The large-cap oriented S&P 500 Index was flat in the second quarter (up 0.10%) and was up 6.02% for the half year. Year-to-date performance was hampered by poor performance of Fund energy stocks and the failure of many holdings to participate in the recent market rally.

Looking first at the stocks that drove the portfolio in the second quarter, Discover Financial Services added 0.77% to the portfolio's return as the company's credit card portfolio continued to heal in the improving economy. This improvement caused investors to increase the valuation they were willing to pay for Discover, bidding up the stock price. Retailers Abercrombie & Fitch and Coach each added approximately 0.60% to the portfolio as their products were well received by consumers.

On the downside, Canacol Energy, an oil and gas explorer/producer, cost the portfolio 0.66% as an exploratory well in Guyana came up dry and the general malaise for Colombian oil producers weighed on the stock. Over the six-month period, energy stocks cost the Fund approximately 3.7% of performance, and were the main laggards in the portfolio. We still believe in these names and will watch them closely as we expect several more drilling results by the end of this year.

Though many of the Fund's stocks did not participate in the stock market rally through June 30, 2011, we believe they have potential to add return in the coming quarters as these companies are growing and we believe they are valued inexpensively compared with their peers.

During the quarter, we sold out of four companies and purchased three new companies. The sales were wireless communications and broadcast tower company American Tower, water treatment applications service provider Nalco Holding Company, for-profit, post-secondary education provider Career Education, and recreational vehicle manufacturer Thor Industries. Our purchases were convention hotelier Gaylord Entertainment, fiber optic sub-systems and components provider Finisar, and electrical and telecom construction services provider Quanta Services. Quanta is a company that we owned previously but sold due to uncertainty about its ability to turn contracts/backlog into sales. There is evidence of this backlog becoming revenue, so we added the company back into the portfolio during the quarter.

I would like to welcome Rob Chalupnik as co-portfolio manager of Columbia Acorn Select. Rob has a strong track record as the domestic industrials analyst at Columbia Wanger Asset Management. I have worked closely with Rob over the years and feel strongly that his knowledge and ability will be additive to the performance of this Fund, not only through his stock picks but through his input on portfolio structure as well.

Thank you for your continued investment in Columbia Acorn Select.

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.

18

Columbia Acorn Select

At a Glance (Class A Shares - LTFAX)

Performance data shown represents past performance and is not a guarantee of future results. The investment return and principal value of an investment will fluctuate so that shares, when redeemed, may be worth more or less than their original cost. Current performance may be lower or higher than the performance data shown. Performance results reflect any fee waivers or reimbursements of Fund expenses by the investment adviser and/or any of its affiliates. Absent these fee waivers and/or expense reimbursement arrangements, performance results would have been lower. Please visit columbiamanagement.com for daily and most recent month-end updates.

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

through June 30, 2011

Inception 10/16/00		Year to date*			1 year			5 years			10 years
Returns before taxes	NAV POP		-0.12 -5.85	%		28.66 21.28	%		4.86 3.63	%		8.05 7.42	%
Returns after taxes on distributions	NAV POP		-0.63 -6.33			28.00 20.66			4.54 3.31			7.79 7.15
Returns after taxes on distributions and sale of fund shares	NAV POP		-0.10 -3.82			18.60 13.81			4.11 3.04			7.07 6.49
S&P MidCap 400 Index** (pretax)			8.56			39.38			6.60			7.94

All results shown assume reinvestment of distributions.

*Year to date data is not annualized.

**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.

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 1.28%.

Columbia Acorn Select Portfolio Diversification

as a percentage of net assets, as of 6/30/11

Columbia Acorn Select Top 10 Holdings

as a percentage of net assets, as of 6/30/11

1.	Discover Financial Services Credit Card Company	6.6	%
2.	Hertz Largest U.S. Rental Car Operator	6.5	%
3.	CNO Financial Group Life, Long-term Care & Medical Supplement Insurance	4.8	%
4.	Ametek Aerospace/Industrial Instruments	4.0	%
5.	Abercrombie & Fitch Teen Apparel Retailer	3.6	%
6.	Sanmina-SCI Electronic Manufacturing Services	3.5	%
7.	Safeway Supermarkets	3.4	%
8.	Pacific Rubiales Energy (Colombia) Oil Production & Exploration in Colombia	3.3	%
9.	Coach Designer & Retailer of Branded Leather Accessories	3.2	%
10.	Crown Castle International Communications Towers	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 June 30, 2011

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 may pay on Fund distributions or on a sale of Fund shares.

Total Net Assets of the Fund: $2.0 billion

†  Class I shares commenced operations on September 27, 2010.

19

Columbia Thermostat Fund

In a Nutshell

Charles P. McQuaid

Lead Portfolio Manager

Performance data shown represents past performance and is not a 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. Current performance may be lower or higher than the performance data shown. Please visit columbiamanagement.com for daily and most recent month-end performance updates.

A "fund of fund" 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 gained 1.38% (Class A shares, without sales charge) in the second quarter of 2011, outperforming the 0.10% gain of its primary equity benchmark, the S&P 500 Index, and underperforming the 2.29% increase of the Fund's primary debt benchmark, the Barclays Capital U.S. Aggregate Bond Index. Year to date through June 30, 2011, the Fund was up 4.44% while the S&P 500 Index had a 6.02% gain and the Barclays index rose 2.72%.

The Fund hit four reallocation triggers during the second quarter. In April, we reduced stock exposure twice on the strength of the equity market and then in May and June returned to stocks as the equity markets declined. The Fund ended the quarter at the same weight it started, with a 60% exposure to its underlying stock funds and 40% exposure to its bond funds.

The bond portion of the portfolio outperformed the equity portion in the quarter with a 1.50% weighted average return versus a 0.93% weighted average gain for equities. Columbia U.S. Treasury Index Fund was the top performing holding for the quarter, up 2.28%. Year to date, Columbia Thermostat's equity portion had a 5.22% weighted average gain versus a 2.83% gain for the income portion. Columbia Large Cap Enhanced Core Fund led performance with a 7.90% gain for the half-year period.

The markets continue to provide the types of ups and downs that Columbia Thermostat Fund was made for. We are pleased to see that the Fund, as expected, provided a return between that of its equity and income benchmarks for the six-month period.

Results of the Funds Owned in Columbia Thermostat Fund as of June 30, 2011

Stock Funds	Weightings			2nd			Year to
Fund	in category			quarter			date
Columbia Acorn International, Class I		20	%		1.69	%		3.06	%
Columbia Dividend Income Fund, Class I		20	%		0.83	%		6.07	%
Columbia Acorn Fund, Class I		15	%		1.47	%		7.22	%
Columbia Marsico Growth Fund, Class I		15	%		0.87	%		6.29	%
Columbia Acorn Select, Class I		10	%		-0.93	%		0.04	%
Columbia Contrarian Core Fund, Class I		10	%		0.60	%		5.66	%
Columbia Large Cap Enhanced Core Fund, Class I		10	%		0.94	%		7.90	%
Weighted Average Equity Return		100	%		0.93	%		5.22	%
Bond Funds	Weightings			2nd			Year
Fund	in category			quarter			to date
Columbia Intermediate Bond Fund, Class I		50	%		1.29	%		2.64	%
Columbia U.S. Treasury Index Fund, Class I		30	%		2.28	%		2.03	%
Columbia Income Opportunities Fund, Class I		20	%		0.82	%		4.39	%
Weighted Average Income Return		100	%		1.50	%		2.83	%

Columbia Thermostat Fund
Rebalancing in the Second Quarter

April 11, 2011	55% stocks, 45% bonds
April 28, 2011	50% stocks, 50% bonds
May 31, 2011	55% stocks, 45% bonds
June 7, 2011	60% stocks, 40% bonds

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 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. 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.

20

Columbia Thermostat Fund

At a Glance (Class A Shares - CTFAX)

Performance data shown represents past performance and is not a guarantee of future results. The investment return and principal value of an investment will fluctuate so that shares, when redeemed, may be worth more or less than their original cost. Current performance may be lower or higher than the performance data shown. Performance results reflect any fee waivers or reimbursements of Fund expenses by the investment adviser and/or any of its affiliates. Absent these fee waivers and/or expense reimbursement arrangements, performance results would have been lower. Please visit columbiamanagement.com for daily and most recent month-end updates.

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

through June 30, 2011

Inception 3/3/03		Year to date*			1 year			5 years			Life of fund
Returns before taxes	NAV POP		4.44 -1.58	%		25.05 17.89	%		5.54 4.31	%		7.95 7.18	%
Returns after taxes on distributions	NAV POP		4.00 -2.00			24.46 17.34			4.30 3.08			6.73 5.97
Returns after taxes on distributions and sale of fund shares	NAV POP		2.88 -1.03			16.35 11.69			4.16 3.10			6.38 5.69
S&P 500 Index** (pretax)			6.02			30.69			2.94			7.68
Barclays Capital U.S. Aggregate Bond Index** (pretax)			2.72			3.90			6.52			4.93
Lipper Flexible Portfolio Funds Index (pretax)			5.11			23.38			5.16			8.35

All results shown assume reinvestment of distributions.

*Year to date data is not annualized.

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

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.

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, 2012. 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 1.52% and 1.29%, 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 6/30/11

Columbia Thermostat Fund Portfolio Weightings

as a percentage of assets in each investment category, as of 6/30/11

Stock Mutual Funds

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

Bond Mutual Funds

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

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

March 3, 2003 through June 30, 2011

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 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 may pay on Fund distributions or on a sale of Fund shares.

Total Net Assets of the Fund: $137.9 million

21

Columbia Acorn Fund

Major Portfolio Changes in the Second Quarter (Unaudited)

	Number of Shares
	03/31/11		06/30/11
Purchases
Information
ANSYS		2,100,000		2,550,000
Boingo Wireless		0		1,200,000
Constant Contact		1,919,615		1,950,000
ExlService Holdings		1,045,000		1,145,000
Genpact		0		781,635
IMAX (Canada)		800,000		1,400,000
Intralinks		0		550,000
Ixia		1,720,000		2,030,000
ON Semiconductor		3,440,000		5,117,000
Polycom		2,305,000		2,455,000
Syntel		0		580,000
TIBCO		0		1,381,600
Verisk Analytics		450,000		900,000
Virtusa		2,064,900		2,125,000
WMS Industries		1,150,000		2,100,000
WNS - ADR (India)		1,000,000		1,027,147
Consumer Goods & Services
Cavco Industries		388,907		415,000
HomeAway		0		1,289,880
MGM China Holdings (Hong Kong)		0		12,000,000
P.F. Chang's China Bistro		300,000		480,000
Phillips-Van Heusen		1,055,000		1,410,000
Thor Industries		1,190,000		1,980,000
Industrial Goods & Services
Albemarle		1,575,972		1,650,000
Imtech (Netherlands)		1,731,432		1,767,165
Kennametal		2,625,000		2,900,000
LKQ		450,000		900,000
Pentair		3,350,000		3,535,000
Quanta Services		1,950,000		2,800,000
Ushio (Japan)		1,322,000		1,500,000
Valmont Industries		0		100,000
Energy & Minerals
Alexco Resource		2,400,000		2,800,000
Celtic Exploration (Canada)		0		175,400
Crew Energy (Canada)		0		484,500
Fugro (Netherlands)		2,570,626		2,641,054
Oil States International		463,954		743,000
Primary Petroleum (Canada)		0		2,245,000
Silver Standard Resources		800,000		900,000
Swift Energy		275,000		550,000
Wolverine Minerals (Canada)		0		4,000,000
Finance
Alliance Data Systems		275,000		400,000
Assured Guaranty		0		300,000
City National		1,045,000		1,145,000

	Number of Shares
	03/31/11		06/30/11
Enstar Group		0		33,746
Financial Engines		0		400,000
First Busey		3,299,507		4,056,427
Health Care
Adcock Ingram Holdings (South Africa)		2,259,000		2,393,955
Akorn		3,733,354		4,000,000
Alimera Sciences		855,298		1,818,154
Anthera Pharmaceuticals		1,450,000		1,740,000
Auxilium Pharmaceuticals		1,200,000		2,400,000
Community Health Systems		1,380,000		1,655,000
InterMune		1,731,000		2,226,000
Kindred Healthcare		0		1,450,000
Nabi Biopharmaceuticals		2,611,936		3,300,000
United Therapeutics		510,000		780,000
Other Industries
Associated Estates Realty		2,200,000		2,700,000
Genesee & Wyoming		100,000		400,000
St. Joe		0		699,701
Summit Hotel Properties		1,092,000		1,481,994

See accompanying notes to financial statements.

22

	Number of Shares
	03/31/11		06/30/11
Sales
Information
AboveNet		1,265,000		1,199,876
Blue Coat Systems		1,260,000		313,300
Crown Castle International		6,300,000		6,000,000
Dionex		300,000		0
Dolby Laboratories		1,140,000		815,000
Hexagon (Sweden)		5,914,999		5,164,999
Informatica		5,200,000		4,700,000
NetSuite		1,800,000		1,450,000
Plexus		1,490,000		1,210,000
SRA International		1,655,000		1,583,750
THQ		3,567,000		0
Consumer Goods & Services
Blue Nile		180,000		62,784
Chico's FAS		2,562,000		1,933,750
CTS Eventim (Germany)		220,000		173,436
Diamond Foods		1,300,000		1,170,000
Hansen Natural		2,200,000		1,900,000
ITT Educational Services		1,080,000		350,000
lululemon athletica		4,035,000		3,991,265
Talbots		4,150,000		828,500
Industrial Goods & Services
American Reprographics		900,000		0
Lumber Liquidators		700,000		0
Mersen (France)		753,000		524,000
Mine Safety Appliances		1,525,000		1,300,000
Mueller Water Products		1,750,000		649,641
Nalco		1,800,000		831,000
Serco (United Kingdom)		2,559,000		0
Simpson Manufacturing		700,000		360,073
Energy & Minerals
Atwood Oceanics		3,200,000		2,399,000
Carrizo Oil & Gas		583,000		293,000
Gran Tierra Energy (Colombia)		3,131,195		0
Pan American Silver (Canada)		500,000		0
Synthesis Energy Systems (China)		1,726,270		1,210,300
Tesco		1,750,000		0
Vaalco Energy		750,000		0
Finance
CAI International		1,450,000		1,123,400
GATX		1,480,000		90,020
Housing Development Finance (India)		1,300,000		0
Investment Technology Group		697,000		629,493
SVB Financial Group		1,260,000		1,160,000
TCF Financial		4,150,000		3,613,000
Wilmington Trust		2,640,000		0

	Number of Shares
	03/31/11		06/30/11
Health Care
Allos Therapeutics		2,755,534		0
American Medical Systems		3,150,000		0
AthenaHealth		500,000		0
Gen-Probe		1,065,000		700,000
Idenix Pharmaceuticals		2,682,497		2,300,000
Nanosphere		964,499		0
Nektar Therapeutics		1,091,990		0
Savient Pharmaceuticals		1,700,000		0
United Drug (Ireland)		826,526		0

See accompanying notes to financial statements.

23

Columbia Acorn Fund

Statement of Investments (Unaudited), June 30, 2011

Number of Shares			Value (000)
			Equities: 97.5%
Information 27.2%
		> Business Software 6.6%
	4,700,000	Informatica (a)	$	274,621
		Enterprise Data Integration Software
	2,550,000	ANSYS (a)		139,408
		Simulation Software for Engineers & Designers
	2,700,000	Micros Systems (a)		134,217
		Information Systems for Hotels, Restaurants & Retailers
	1,100,000	Quality Systems		96,030
		IT Systems for Medical Groups & Ambulatory Care Centers
	1,480,000	Concur Technologies (a)		74,104
		Web Enabled Cost & Expense Management Software
	1,700,000	Blackboard (a)(b)		73,763
		Education Software
	2,250,000	Blackbaud (c)		62,370
		Software & Services for Non-profits
	1,450,000	NetSuite (a)(b)		56,840
		End to End IT Systems Solutions Delivered Over the Web
	2,000,000	Tyler Technologies (a)(c)		53,560
		Financial, Tax, Court & Document Management Systems for Local Governments
	1,950,000	Constant Contact (a)(b)(c)		49,491
		E-mail & Other Marketing Campaign Management Systems Delivered Over the Web
	2,025,000	Kenexa (a)(c)		48,560
		Recruiting & Workforce Management Solutions
	1,200,000	Ariba (a)		41,364
		Cost Management Software
	1,381,600	TIBCO (a)		40,094
		Datacenter Software
	850,000	Red Hat (a)		39,015
		Maintenance & Support for Open Source & Middleware
	920,000	Jack Henry & Associates		27,609
		Systems Financial Institutions
	690,000	Advent Software (a)		19,437
		Asset Management & Trading Systems
	900,000	SPS Commerce (a)(c)		16,011
		Supply Chain Management Software Delivered via the Web
	550,000	Intralinks (a)		9,504
		Collaboration Software
	1,500,000	Actuate (a)		8,775
		Information Delivery Software & Solutions
	1,000,000	InContact (a)		4,750
		Call Center Systems Delivered via the Web & Telecommunications Services
				1,269,523
		> Instrumentation 3.7%
	1,600,000	Mettler Toledo (a)		269,872
		Laboratory Equipment
	2,780,000	IPG Photonics (a)(c)		202,134
		Fiber Lasers

Number of Shares			Value (000)
	5,164,999	Hexagon (Sweden)	$	127,222
		Measurement Equipment & Software
	2,035,000	Trimble Navigation (a)		80,667
		GPS-based Instruments
	600,000	FLIR Systems		20,226
		Infrared Cameras
	400,000	Hamamatsu Photonics (Japan)		17,295
		Optical Sensors for Medical & Industrial Applications
				717,416
		> Computer Hardware & Related Equipment 2.7%
	3,565,000	Amphenol		192,474
		Electronic Connectors
	4,550,000	II-VI (a)(c)		116,480
		Laser Optics & Specialty Materials
	1,605,000	Zebra Technologies (a)		67,683
		Bar Code Printers
	1,200,000	Netgear (a)		52,464
		Networking Products for Small Business & Home
	815,000	Dolby Laboratories (a)		34,605
		Audio Technology for Consumer Electronics
	800,000	Nice Systems - ADR (Israel) (a)		29,088
		Audio & Video Recording Solutions
	605,000	Stratasys (a)		20,389
		Rapid Prototyping Systems
				513,183
		> Semiconductors & Related Equipment 2.1%
	8,130,000	Atmel (a)		114,389
		Microcontrollers, Radio Frequency & Memory Semiconductors
	5,117,000	ON Semiconductor (a)		53,575
		Mixed-signal & Power Management Semiconductors
	5,000,000	Entegris (a)		50,600
		Semiconductor Materials Management Products
	2,345,000	Microsemi (a)		48,072
		Analog/Mixed-signal Semiconductors
	500,000	Littelfuse		29,360
		Little Fuses
	1,900,000	IXYS (a)(c)		28,462
		Power Semiconductors
	935,000	Supertex (a)(c)		20,944
		Analog/Mixed-signal Semiconductors
	1,750,000	TriQuint Semiconductor (a)		17,833
		Radio Frequency Semiconductors
	1,765,000	Pericom Semiconductor (a)(c)		15,779
		Interface Integrated Circuits (ICs) & Frequency Control Products
	1,650,000	Applied Micro Circuits (a)		14,619
		Communications Semiconductors
	800,000	Monolithic Power Systems (a)		12,336
		High Performance Analog & Mixed-signal Integrated Circuits (ICs)
				405,969

See accompanying notes to financial statements.

24

Number of Shares			Value (000)
		> Telephone and Data Services 2.1%
	9,500,000	tw telecom (a)(c)	$	195,035
		Fiber Optic Telephone/Data Services
	1,199,876	AboveNet		84,543
		Metropolitan Fiber Communications Services
	9,600,000	PAETEC Holding (a)(c)		45,984
		Telephone/Data Services for Business
	2,520,000	Cogent Communications (a)(c)		42,865
		Internet Data Pipelines
	2,000,000	General Communications (a)		24,140
		Commercial Communications & Consumer CATV, Web & Phone in Alaska
	1,200,000	Boingo Wireless (a)(b)		10,896
		Wholesale & Retail WiFi Networks
				403,463
		> Mobile Communications 2.0%
	6,000,000	Crown Castle International (a)		244,740
		Communications Towers
	3,150,000	SBA Communications (a)		120,298
		Communications Towers
	1,000,000	MetroPCS Communications (a)		17,210
		Discount Cellular Telephone Services
	1,500,000	Globalstar (a)(b)		1,845
		Satellite Mobile Voice & Data Carrier
				384,093
		> Telecommunications Equipment 1.6%
	2,455,000	Polycom (a)		157,856
		Video Conferencing Equipment
	685,000	F5 Networks (a)		75,521
		Internet Traffic Management Equipment
	1,725,000	Finisar (a)		31,102
		Optical Sub-systems & Components
	2,030,000	Ixia (a)		25,984
		Telecom Network Test Equipment
	1,925,000	Infinera (a)		13,302
		Optical Networking Equipment
	313,300	Blue Coat Systems (a)		6,849
		WAN Acceleration & Network Security
				310,614
		> Computer Services 1.4%
	1,583,750	SRA International (a)		48,970
		Government IT Services
	2,900,000	iGate (b)(c)		47,328
		IT & BPO (Business Process Outsourcing) Services
	2,125,000	Virtusa (a)(c)		40,269
		Offshore IT Outsourcing
	580,000	Syntel		34,290
		Offshore I/T Services
	1,145,000	ExlService Holdings (a)		26,449
		BPO (Business Process Outsourcing)
	4,500,000	Hackett Group (a)(c)		22,905
		IT Integration & Best Practice Research
	1,560,000	Acxiom (a)		20,452
		Database Marketing Services
	781,635	Genpact (a)		13,475
		Business Process Outsourcing

Number of Shares			Value (000)
	1,027,147	WNS - ADR (India) (a)	$	9,131
		Offshore BPO (Business Process Outsourcing) Services
				263,269
		> Gaming Equipment & Services 1.1%
	3,725,000	Bally Technologies (a)(b)(c)		151,533
		Slot Machines & Software
	2,100,000	WMS Industries (a)		64,512
		Slot Machine Provider
				216,045
		> CATV 1.0%
	3,000,000	Discovery Communications, Series C (a)		109,650
		Cable TV Programming
	1,250,000	Liberty Global, Series A (a)(b)		56,300
		Cable TV Franchises Outside the USA
	17,770	Jupiter Telecommunications (Japan)		19,881
		Largest Cable Service Provider in Japan
				185,831
		> Financial Processors 0.9%
	2,429,000	Global Payments		123,879
		Credit Card Processor
	5,000,000	Singapore Exchange (Singapore)		30,725
		Singapore Equity & Derivatives Market Operator
	750,000	Hong Kong Exchanges and Clearing (Hong Kong)		15,802
		Hong Kong Equity & Derivatives Market Operator
				170,406
		> Electronics Distribution 0.5%
	3,125,000	Avnet (a)		99,625
		Electronic Components Distribution
				99,625
		> Business Information & Marketing Services 0.5%
	900,000	FTI Consulting (a)(b)		34,146
		Financial Consulting Firm
	3,100,000	Navigant Consulting (a)(c)		32,519
		Financial Consulting Firm
	900,000	Verisk Analytics (a)		31,158
		Risk & Decision Analytics
				97,823
		> Contract Manufacturing 0.4%
	1,210,000	Plexus (a)		42,120
		Electronic Manufacturing Services
	2,800,000	Sanmina-SCI (a)		28,924
		Electronic Manufacturing Services
				71,044
		> Internet Related 0.3%
	435,000	Equinix (a)		43,944
		Network Neutral Data Centers
	464,305	Mail.ru - GDR (Russia) (a)(d)		15,424
		Internet Social Networking & Games for Russian Speakers
	1,000,000	TheStreet.com		3,070
		Financial Information Websites
				62,438

See accompanying notes to financial statements.

25

Columbia Acorn Fund

Statement of Investments (Unaudited), continued

Number of Shares			Value (000)
		> Entertainment Programming 0.2%
	1,400,000	IMAX (Canada) (a)	$	45,402
		IMAX Movies, Theatre Equipment & Theatre Joint Ventures
				45,402
		> Radio 0.1%
	164,991	Saga Communications (a)		6,105
		Radio Stations in Small & Mid-sized Cities
	1,541,000	Salem Communications (c)		5,532
		Radio Stations for Religious Programming
	2,400,000	Spanish Broadcasting System (a)(c)		1,680
		Spanish Language Radio Stations
				13,317
		> TV Broadcasting —%
	2,500,000	Entravision Communications (a)		4,625
		Spanish Language TV & Radio Stations
	1,750,000	Gray Television (a)(b)		4,620
		Mid-market Affiliated TV Stations
				9,245
		> Advertising —%
	1,500,000	VisionChina Media - ADR (China) (a)(b)		4,245
		Advertising on Digital Screens in China's Mass Transit System
				4,245
Information: Total				5,242,951
Consumer Goods & Services 18.3%
		> Retail 5.2%
	3,991,265	lululemon athletica (a)(c)		446,304
		Premium Active Apparel Retailer
	3,510,000	Abercrombie & Fitch		234,889
		Teen Apparel Retailer
	2,300,000	Shutterfly (a)(c)		132,066
		Internet Photo-centric Retailer
	5,600,000	Pier 1 Imports (a)		64,792
		Home Furnishing Retailer
	5,225,000	Saks (a)		58,363
		Luxury Department Store Retailer
	1,933,750	Chico's FAS		29,451
		Women's Specialty Retailer
	525,000	DSW (a)		26,570
		Branded Footwear Retailer
	1,371,366	Gaiam (c)		6,816
		Healthy Living Catalogs & E-Commerce
	828,500	Talbots (a)(b)		2,767
		Women's Specialty Retailer
	62,784	Blue Nile (a)(b)		2,761
		Online Jewelry Retailer
	66,000	The Fresh Market (a)		2,553
		Specialty Food Retailer
				1,007,332
		> Apparel 3.5%
	2,100,000	Coach		134,253
		Designer & Retailer of Branded Leather Accessories

Number of Shares			Value (000)
	2,190,000	Warnaco Group (a)	$	114,427
		Global Branded Apparel Manufacturer
	1,120,000	Deckers Outdoor (a)		98,717
		Fashion Footwear Wholesaler
	1,410,000	Phillips-Van Heusen		92,313
		Apparel Wholesaler & Retailer
	1,980,000	Guess?		83,279
		Branded Apparel, Accessories & Licensor
	2,047,000	True Religion Apparel (a)(c)		59,527
		Premium Denim
	1,400,000	Crocs (a)		36,050
		Branded Footwear Wholesaler & Retailer
	1,000,000	Hanesbrands (a)		28,550
		Apparel Wholesaler
	600,000	Steven Madden (a)		22,506
		Wholesaler/Retailer of Fashion Footwear
	100,197	Zuoan Fashion (China) (a)(b)		560
		Men's Apparel Provider in China
				670,182
		> Travel 2.8%
	3,850,000	Gaylord Entertainment (a)(c)		115,500
		Convention Hotels
	3,900,000	Expedia		113,061
		Online Travel Services Company
	4,600,000	Avis Budget Group (a)		78,614
		Second Largest Car Rental Company
	1,250,000	Vail Resorts		57,775
		Ski Resort Operator & Developer
	1,289,880	HomeAway (a)		49,919
		Vacation Rental Online Marketplace
	3,000,000	Hertz (a)		47,640
		Largest U.S. Rental Car Operator
	2,000,000	Localiza Rent A Car (Brazil)		35,754
		Car Rental
	970,000	Choice Hotels		32,359
		Franchisor of Budget Hotel Brands
				530,622
		> Food & Beverage 1.7%
	1,900,000	Hansen Natural (a)		153,805
		Alternative Beverages
	1,170,000	Diamond Foods (b)(c)		89,318
		Snack Foods & Culinary Ingredients
	32,896,000	Olam International (Singapore)		73,128
		Agriculture Supply Chain Manager
	1,200,000	GLG Life Tech (Canada) (a)		8,064
		Produce an All-natural Sweetener Extracted from the Stevia Plant
	240,000	Lance		5,191
		Snack Foods
				329,506
		> Furniture & Textiles 0.9%
	4,000,000	Knoll (c)		80,280
		Office Furniture
	2,800,000	Herman Miller		76,216
		Office Furniture
	1,000,000	Interface		19,370
		Modular & Broadloom Carpet
				175,866

See accompanying notes to financial statements.

26

Number of Shares			Value (000)
		> Casinos & Gaming 0.9%
	1,590,000	Penn National Gaming (a)	$	64,141
		Regional Casino Operator
	3,400,000	Pinnacle Entertainment (a)(c)		50,660
		Regional Casino Operator
	3,000,000	Melco Crown Entertainment - ADR (Hong Kong) (a)		38,310
		Macau Casino Operator
	12,000,000	MGM China Holdings (Hong Kong) (a)		22,144
		Macau Casino Operator
				175,255
		> Educational Services 0.7%
	2,800,000	Career Education (a)		59,220
		Post-secondary Education
	1,700,000	Universal Technical Institute (c)		33,609
		Vocational Training
	350,000	ITT Educational Services (a)(b)		27,384
		Post-secondary Degree Services
	200,000	New Oriental Education & Technology - ADR (China) (a)		22,344
		Education Service Provider
	2,000,000	Voyager Learning, Contingent Value Rights (a)(d)		300
		Education Services for the K-12 Market
				142,857
		> Other Consumer Services 0.7%
	2,190,000	Lifetime Fitness (a)(c)		87,403
		Sport & Fitness Club Operator
	14,000,000	Lifestyle International (Hong Kong)		41,319
		Mid- to High-end Department Store Operator in Hong Kong & China
	4,250,000	Move (a)		9,307
		Real Estate Internet Websites
	1,325,000	IFM Investments (Century 21 China RE) - ADR (China) (a)		1,948
		Provides Real Estate Services in China
				139,977
		> Other Durable Goods 0.5%
	1,720,000	Jarden		59,357
		Branded Household Products
	415,000	Cavco Industries (a)(c)		18,675
		Manufactured Homes
	400,000	Tesla Motors (a)(b)		11,652
		Design, Manufacture & Sell High Performance Electric Vehicles
				89,684
		> Restaurants 0.4%
	2,000,000	AFC Enterprises (a)(c)		32,900
		Popeye's Restaurants
	480,000	P.F. Chang's China Bistro		19,315
		Mandarin Style Restaurants
	675,000	Bravo Brio Restaurant Group (a)		16,490
		Upscale Casual Italian Restaurants
	450,000	Cheesecake Factory (a)		14,117
		Casual Dining Restaurants
				82,822

Number of Shares			Value (000)
		> Consumer Goods Distribution 0.3%
	2,100,000	Pool	$	62,601
		Distributor of Swimming Pool Supplies & Equipment
				62,601
		> Leisure Products 0.3%
	1,980,000	Thor Industries		57,103
		RV & Bus Manufacturer
				57,103
		> Nondurables 0.3%
	1,600,000	Helen of Troy (a)(c)		55,248
		Hair Dryers & Curling Irons
				55,248
		> Other Entertainment 0.1%
	173,436	CTS Eventim (Germany)		11,984
		Event Ticket Sales
				11,984
Consumer Goods & Services: Total				3,531,039
Industrial Goods & Services 18.3%
		> Machinery 10.1%
	6,750,000	Ametek		303,075
		Aerospace/Industrial Instruments
	4,200,000	Donaldson (c)		254,856
		Industrial Air Filtration
	3,000,000	Nordson		164,550
		Dispensing Systems for Adhesives & Coatings
	3,535,000	Pentair		142,673
		Pumps & Water Treatment
	2,900,000	Kennametal		122,409
		Consumable Cutting Tools
	2,565,000	Clarcor (c)		121,273
		Mobile & Industrial Filters
	3,650,000	Oshkosh (a)		105,631
		Specialty Truck Manufacturer
	1,800,000	Pall		101,214
		Filtration & Fluids Clarification
	2,250,000	HEICO (c)		89,460
		FAA Approved Aircraft Replacement Parts
	2,050,000	MOOG (a)		89,216
		Motion Control Products for Aerospace, Defense & Industrial Markets
	2,200,000	ESCO Technologies (c)		80,960
		Automatic Electric Meter Readers
	1,150,000	WABCO Holdings (a)		79,419
		Truck & Bus Component Supplier
	805,000	Toro		48,703
		Turf Maintenance Equipment
	1,300,000	Mine Safety Appliances		48,542
		Safety Equipment
	1,300,000	Kaydon		48,516
		Specialized Friction & Motion Control Products
	600,000	Wabtec		39,432
		Freight & Transit Component Supplier
	1,600,000	Generac (a)		31,040
		Stand-by Power Generators
	287,000	Neopost (France)		24,655
		Postage Meter Machines

See accompanying notes to financial statements.

27

Columbia Acorn Fund

Statement of Investments (Unaudited), continued

Number of Shares			Value (000)
		> Machinery—continued
	3,500,000	Jain Irrigation Systems (India)	$	13,382
		Agricultural Micro-irrigation Systems & Food Processing
	10,000,000	Marel (Iceland) (a)		10,586
		Largest Manufacturer of Poultry & Fish Processing Equipment
	100,000	Valmont Industries		9,639
		Center Pivot Irrigation Systems & Utility Poles
	1,250,000	Spartan Motors		6,750
		Specialty Truck & Chassis Manufacturer
				1,935,981
		> Industrial Materials & Specialty Chemicals 2.4%
	1,650,000	Albemarle		114,180
		Refinery Catalysts & Other Specialty Chemicals
	650,000	FMC Corp.		55,913
		Niche Specialty Chemicals
	340,000	Novozymes (Denmark)		55,329
		Industrial Enzymes
	673,000	Sociedad Quimica y Minera de Chile - ADR (Chile)		43,557
		Producer of Specialty Fertilizers, Lithium & Iodine
	1,260,000	Drew Industries (c)		31,147
		RV & Manufactured Home Components
	524,000	Mersen (France)		29,559
		Advanced Industrial Materials
	1,100,000	Albany International		29,029
		Paper Machine Clothing & Advanced Textiles
	10,000	Sika (Switzerland)		24,109
		Chemicals for Construction & Industrial Applications
	831,000	Nalco		23,110
		Provider of Water Treatment & Process Chemicals & Services
	350,000	Greif		22,761
		Industrial Packaging
	2,218,700	Kansai Paint (Japan)		20,215
		Paint Producer in Japan, India, China & Southeast Asia
	400,000	Silgan Holdings		16,388
		Metal & Plastic Packaging
				465,297
		> Other Industrial Services 2.0%
	3,200,000	Expeditors International of Washington		163,808
		International Freight Forwarder
	1,767,165	Imtech (Netherlands)		62,503
		Electromechanical & Information & Communications Technologies Installation & Maintenance
	1,300,000	Forward Air		43,927
		Freight Transportation Between Airports
	1,600,000	Mobile Mini (a)		33,904
		Portable Storage Units Leasing
	900,000	LKQ (a)		23,481
		Alternative Auto Parts Distribution
	1,000,000	UTI Worldwide		19,690
		Freight Forwarding & Logistics

Number of Shares			Value (000)
	626,524	Arcadis (Netherlands)	$	15,327
		Engineering Consultants
	1,050,000	TrueBlue (a)		15,204
		Temporary Manual Labor
	10,000,000	Hutchison Port Holdings Trust (Hong Kong) (a)		8,450
		Southern China Container Ports
				386,294
		> Industrial Distribution 1.0%
	900,000	WW Grainger		138,285
		Industrial Distribution
	2,600,000	Interline Brands (a)(c)		47,762
		Industrial Distribution
	100,000	Watsco		6,799
		HVAC Distribution
				192,846
		> Electrical Components 0.6%
	1,440,000	Acuity Brands		80,323
		Commercial Lighting Fixtures
	1,500,000	Ushio (Japan)		29,659
		Industrial Light Sources
	351,000	Saft (France)		12,071
		Niche Battery Manufacturer
				122,053
		> Waste Management 0.6%
	1,672,500	Waste Connections		53,068
		Solid Waste Management
	1,000,000	Republic Services		30,850
		Solid Waste Management
	280,000	Clean Harbors (a)		28,910
		Hazardous Waste Services & Disposal
				112,828
		> Outsourcing Services 0.5%
	2,800,000	Quanta Services (a)		56,560
		Electrical & Telecom Construction Services
	1,210,000	Insperity		35,828
		Professional Employer Organization
	600,000	GP Strategies (a)		8,196
		Training Programs
				100,584
		> Construction 0.4%
	66,000	NVR (a)		47,882
		D.C. Homebuilder
	1,800,000	Mills Estruturas e Serviços de Engenharia (Brazil)		25,951
		Civil Engineering & Construction
	360,073	Simpson Manufacturing		10,755
		Wall Joint Maker
				84,588
		> Conglomerates 0.4%
	2,263,654	Aalberts Industries (Netherlands)		52,916
		Flow Control & Heat Treatment
	600,000	Ibiden (Japan)		18,785
		Electronic Parts & Ceramics
				71,701

See accompanying notes to financial statements.

28

Number of Shares			Value (000)
		> Steel 0.3%
	2,340,000	GrafTech International (a)	$	47,432
		Industrial Graphite Materials Producer
				47,432
		> Water —%
	649,641	Mueller Water Products		2,586
		Fire Hydrants, Valves & Ductile Iron Pipes
				2,586
Industrial Goods & Services: Total				3,522,190
Energy & Minerals 9.8%
		> Oil Services 3.9%
	6,200,000	FMC Technologies (a)		277,698
		Oil & Gas Wellhead Manufacturer
	2,641,054	Fugro (Netherlands)		190,424
		Sub-sea Oilfield Services
	2,399,000	Atwood Oceanics (a)		105,868
		Offshore Drilling Contractor
	743,000	Oil States International (a)		59,373
		Diversified North American Oil Service Provider
	1,670,000	ShawCor (Canada)		51,289
		Oil & Gas Pipeline Products
	375,000	Bristow		19,132
		Largest Provider of Helicopter Services to Offshore Oil & Gas Producers
	528,300	Black Diamond Group (Canada)		17,255
		Provides Accommodations/Equipment for Oil Sands Exploitation
	500,000	Hornbeck Offshore (a)		13,750
		Supply Vessel Operator in U.S. Gulf of Mexico
	2,890,900	Horizon North Logistics (Canada)		13,429
		Provides Diversified Oil Service Offering in Northern Canada
	9,519,200	Tuscany International Drilling (Colombia) (a)		9,080
	1,040,000	Tuscany International Drilling - Warrants (Colombia) (a)		38
		South America-based Drilling Rig Contractor
				757,336
		> Oil & Gas Producers 3.7%
	4,810,550	Pacific Rubiales Energy (Colombia)		128,936
		Oil Production & Exploration in Colombia
	1,650,000	Southwestern Energy (a)		70,752
		Oil & Gas Producer
	2,700,000	Denbury Resources (a)		54,000
		Oil Producer Using Co2 Injection
	715,000	SM Energy		52,538
		Oil & Gas Producer
	974,000	Rosetta Resources (a)		50,200
		Oil & Gas Producer Exploring in South Texas & Montana
	2,400,000	Tullow Oil (United Kingdom)		47,763
		Oil & Gas Producer
	910,000	Ultra Petroleum (a)		41,678
		Oil & Gas Producer

Number of Shares			Value (000)
	695,000	Range Resources	$	38,572
		Oil & Gas Producer
	650,000	Baytex (Canada) (b)		35,531
		Oil & Gas Producer in Canada
	1,200,000	Houston American Energy (b)		21,756
		Oil & Gas Exploration & Production in Colombia
	27,063,400	ShaMaran Petroleum (Iraq) (a)		21,326
		Oil Exploration in Kurdistan
	550,000	Swift Energy (a)		20,499
		Oil & Gas Exploration & Production Company
	850,000	Northern Oil & Gas (a)(b)		18,828
		Small E&P Company in North Dakota Bakken
	250,000	Cabot Oil & Gas		16,578
		Large Natural Gas Producer in Appalachia & Gulf Coast
	293,000	Carrizo Oil & Gas (a)		12,233
		Oil & Gas Producer
	37,500,000	Petromanas (Canada) (a)(c)(d)		11,050
	18,750,000	Petromanas - Warrants (Canada) (a)(c)(d)		476
		Exploring for Oil in Albania
	26,000,000	Petrodorado (Colombia) (a)(c)		8,222
	24,000,000	Petrodorado - Warrants (Colombia) (a)(c)(d)		2,436
		Oil & Gas Exploration & Production in Colombia, Peru & Paraguay
	42,580,500	Alange Energy (Colombia) (a)(b)		9,713
		Oil & Gas Exploration & Production in Colombia
	484,500	Crew Energy (Canada) (a)		7,535
		Canadian Oil & Gas Producer
	575,000	Venoco (a)		7,326
		Oil & Gas Producer in California & Texas
	6,300,000	Canacol Energy (Colombia) (a)(d)		6,786
		Oil Producer in South America
	228,200	Oasis Petroleum (a)		6,773
		Oil Producer in North Dakota
	1,198,100	Pan Orient (Canada) (a)		6,659
		Growth Oriented & Return Focused Asian Explorer
	30,275,000	Petroamerica (Colombia) (a)(c)		5,023
		Oil Exploration & Production in Colombia
	8,400,000	Canadian Overseas Petroleum (United Kingdom) (a)(d)		3,884
	4,200,000	Canadian Overseas Petroleum - Warrants (United Kingdom) (a)(d)		572
		Oil & Gas Exploration/Production in the North Sea
	41,100,000	Quetzal Energy (Colombia) (a)(c)(d)		3,273
	8,900,000	Quetzal Energy (Colombia) (a)(c)		738
		Explores for Oil & Gas in Latin America
	175,400	Celtic Exploration (Canada) (a)		3,879
		Canadian Oil & Gas Producer
	2,245,000	Primary Petroleum (Canada) (a)		1,117
		Targeting Oil Deposits in Western Montana
				716,652

See accompanying notes to financial statements.

29

Columbia Acorn Fund

Statement of Investments (Unaudited), continued

Number of Shares			Value (000)
		> Mining 1.6%
	641,000	Core Laboratories (Netherlands) (b)	$	71,497
		Oil & Gas Reservoir Consulting
	1,950,000	Silver Wheaton (Canada)		64,350
		Silver Mining Royalty Company
	15,000,000	Zhaojin Mining Industry (China)		30,945
		Gold Mining & Refining in China
	1,150,000	Ivanhoe Mines (Canada) (a)		29,059
		Copper Mine Project in Mongolia
	4,432,000	Northam Platinum (South Africa)		27,837
		Platinum Mining in South Africa
	900,000	Silver Standard Resources (a)		24,021
		Silver Mining
	2,800,000	Alexco Resource (a)		20,188
		Mining, Exploration & Environmental Services
	5,000,000	Orko Silver (Canada) (a)(b)		14,464
		Silver Exploration & Development
	3,816,400	Duluth Metals (Canada) (a)		9,418
		Copper & Nickel Miner
	5,215,500	Mongolian Mining (Hong Kong) (a)		6,449
		Coking Coal Mining in Mongolia
	236,400	Tahoe Resources (Canada) (a)(d)		4,368
		Silver Project in Guatemala
	800,000	Augusta Resource (a)		3,704
		U.S. Copper/Molybdenum Mine
	4,000,000	Wolverine Minerals (Canada) (a)(c)(d)		2,389
	2,000,000	Wolverine Minerals - Warrants (Canada) (a)(c)(d)		281
		Gold Miner
				308,970
		> Alternative Energy 0.3%
	3,000,000	GT Solar International (a)(b)		48,600
		Largest Manufacturer of Furnaces & Reactors to Produce & Cast Polysilicon
	500,000	STR Holdings (a)(b)		7,460
		Makes Encapsulant for Solar Power Modules/Provides Quality Assurance
	1,210,300	Synthesis Energy Systems (China) (a)(b)		2,263
		Owner/Operator of Gasification Plants
				58,323
		> Oil Refining, Marketing & Distribution 0.2%
	600,000	Vopak (Netherlands)		29,400
		World's Largest Operator of Petroleum & Chemical Storage Terminals
				29,400
		> Agricultural Commodities 0.1%
	6,818,182	Union Agriculture Group (Argentina) (a)(d)		15,000
		Farmland Operator in Uruguay
				15,000
Energy & Minerals: Total				1,885,681

Number of Shares			Value (000)
Finance 9.5%
		> Banks 3.9%
	2,800,000	BOK Financial	$	153,356
		Tulsa-based Southwest Bank
	6,304,320	Valley National Bancorp (b)		85,802
		New Jersey/New York Bank
	5,413,800	Associated Banc-Corp		75,252
		Midwest Bank
	2,337,313	Hancock Holding (b)		72,410
		Gulf Coast Bank
	1,160,000	SVB Financial Group (a)		69,264
		Bank to Venture Capitalists
	1,145,000	City National		62,116
		Bank & Asset Manager
	2,860,000	MB Financial (c)		55,026
		Chicago Bank
	3,613,000	TCF Financial		49,859
		Great Lakes Bank
	4,300,000	CVB Financial (b)		39,775
		Inland Empire Business Bank
	4,056,427	First Busey		21,458
		Illinois Bank
	1,121,188	Sandy Spring Bancorp		20,170
		Baltimore/D.C. Bank
	1,350,000	TriCo Bancshares (c)		19,710
		California Central Valley Bank
	772,632	Hudson Valley		14,920
		Metro New York City Bank
	706,559	Eagle Bancorp (a)		9,397
		Metro D.C. Bank
	3,764,300	Shinsei Bank (Japan)		3,765
		Commercial Bank
	246,505	Pacific Continental		2,256
		Pacific Northwest Bank
	583,872	Green Bankshares (a)(b)		1,530
		Tennessee Bank
				756,066
		> Insurance 2.2%
	2,820,000	Leucadia National		96,162
		Insurance Holding Company
	9,400,000	CNO Financial Group (a)		74,354
		Life, Long-term Care & Medical Supplement Insurance
	1,320,000	Hanover Insurance Group		49,777
		Personal & Commercial Lines Insurance
	1,200,000	HCC Insurance Holdings		37,800
		Specialty Insurance
	832,000	Willis Group (Ireland)		34,204
		Insurance Broker
	1,000,000	Delphi Financial Group		29,210
		Workers Compensation & Group Employee Benefit Products & Services
	1,225,000	Tower Group		29,180
		Commercial & Personal Lines Insurance
	1,420,000	Selective Insurance Group		23,103
		Commercial & Personal Lines Insurance
	900,000	Brown & Brown		23,094
		Insurance Broker
	1,600,000	Symetra Financial		21,488
		Life Insurance

See accompanying notes to financial statements.

30

Number of Shares			Value (000)
		> Insurance—continued
	300,000	Assured Guaranty	$	4,893
		Global Muni Bond Insurance
	33,746	Enstar Group (a)		3,526
		Insurance/Reinsurance & Related Services
				426,791
		> Finance Companies 1.6%
	1,505,202	World Acceptance (a)(c)		98,696
		Personal Loans
	2,350,000	McGrath Rentcorp (c)		65,988
		Temporary Space & IT Rentals
	2,300,000	Aaron's		64,998
		Rent to Own
	3,000,000	H&E Equipment Services (a)(c)		41,970
		Heavy Equipment Leasing
	1,123,400	CAI International (a)(c)		23,209
		International Container Leasing
	1,091,000	Marlin Business Services (a)(c)		13,801
		Small Equipment Leasing
	90,020	GATX		3,342
		Rail Car Lessor
	78,500	Textainer Group Holdings		2,413
		Top International Container Leasor
				314,417
		> Brokerage & Money Management 1.4%
	6,198,000	SEI Investments		139,517
		Mutual Fund Administration & Investment Management
	3,391,000	Eaton Vance		102,510
		Specialty Mutual Funds
	400,000	Financial Engines (a)		10,368
		Asset management for 401k plans
	629,493	Investment Technology Group (a)		8,825
		Electronic Trading
				261,220
		> Credit Cards 0.2%
	400,000	Alliance Data Systems (a)(b)		37,628
		Diversified Credit Card Provider
				37,628
		> Savings & Loans 0.2%
	1,024,069	ViewPoint Financial		14,132
		Texas Thrift
	1,010,000	Provident New York Bancorp		8,444
		New York State Thrift
	452,146	Kaiser Federal Financial Group		5,570
		Los Angeles Savings & Loan
	65,991	Berkshire Hills Bancorp		1,478
		Northeast Thrift
				29,624
Finance: Total				1,825,746
Health Care 8.6%
		> Biotechnology & Drug Delivery 3.2%
	4,315,000	BioMarin Pharmaceutical (a)		117,411
		Biotech Focused on Orphan Diseases
	4,181,000	Seattle Genetics (a)(b)		85,794
		Antibody-based Therapies for Cancer

Number of Shares			Value (000)
	2,226,000	InterMune (a)	$	79,802
		Drugs for Pulmonary Fibrosis & Hepatitis C
	1,450,000	Onyx Pharmaceuticals (a)		51,185
		Commercial-stage Biotech Focused on Cancer
	2,400,000	Auxilium Pharmaceuticals (a)(c)		47,040
		Biotech Focused on Niche Disease Areas
	780,000	United Therapeutics (a)		42,978
		Biotech Focused on Rare Diseases
	4,500,000	NPS Pharmaceuticals (a)(c)		42,525
		Orphan Drugs & Healthy Royalties
	4,500,000	Isis Pharmaceuticals (a)		41,220
		Biotech Pioneer in Anti-sense Drugs
	5,500,000	Micromet (a)(b)(c)		31,570
		Next-generation Antibody Technology
	4,549,900	Chelsea Therapeutics (a)(b)(c)		23,205
		Biotech Focused on Rare Diseases
	3,300,000	Nabi Biopharmaceuticals (a)(c)		17,754
		Biotech Focused on Vaccines
	1,740,000	Anthera Pharmaceuticals (a)(b)(c)		14,216
		Biotech Focused on Cardiovascular, Cancer & Immunology
	2,300,000	Idenix Pharmaceuticals (a)		11,500
		Developer of Drugs for Infectious Diseases
	3,500,000	Array Biopharma (a)(c)		7,840
		Drugs for Cancer & Inflammatory Diseases
	359,944	MicroDose Technologies (a)(d)		374
		Drug Inhaler Development
	94,715	Locus Pharmaceuticals (a)(d)(e)		—
		High Throughput Rational Drug Design
				614,414
		> Medical Equipment & Devices 2.8%
	4,200,000	Alexion Pharmaceuticals (a)(b)		197,526
		Biotech Focused on Orphan Diseases
	1,800,000	Sirona Dental Systems (a)		95,580
		Manufacturer of Dental Equipment
	1,000,000	Edwards Lifesciences (a)		87,180
		Heart Valves
	700,000	Gen-Probe (a)		48,405
		Molecular In-vitro Diagnostics
	500,000	Idexx Laboratories (a)		38,780
		Diagnostic Equipment & Services for Veterinarians
	550,000	Haemonetics (a)		35,403
		Blood & Plasma Collection Equipment
	570,000	Orthofix International (a)		24,208
		Bone Fixation & Stimulation Devices
	1,650,000	Pacific Biosciences of California (a)(b)		19,305
		Genome Sequencing
				546,387
		> Medical Supplies 1.3%
	3,200,000	Cepheid (a)(c)		110,848
		Molecular Diagnostics
	2,126,000	Patterson Companies		69,924
		Dental, Veterinarian & Medical Distributor
	650,000	Henry Schein (a)		46,534
		Largest Distributor of Healthcare Products
	325,200	Neogen (a)		14,702
		Food & Animal Safety Products

See accompanying notes to financial statements.

31

Columbia Acorn Fund

Statement of Investments (Unaudited), continued

Number of Shares			Value (000)
		> Medical Supplies—continued
	200,000	Owens & Minor	$	6,898
		Distribution of Medical Supplies
				248,906
		> Health Care Services 0.8%
	1,655,000	Community Health Systems (a)		42,500
		Non-urban Hospitals
	3,800,000	Health Management Associates (a)		40,964
		Non-urban Hospitals
	400,000	HMS Holdings (a)		30,748
		Cost Containment Services
	4,250,000	eResearch Technology (a)(c)		27,073
		Clinical Research Services
	700,000	Allscripts Healthcare Solutions (a)		13,594
		IT for Physician Offices & Hospitals
				154,879
		> Pharmaceuticals 0.3%
	4,000,000	Akorn (a)		28,000
		Develops, Manufactures & Sells Specialty Generic Drugs
	2,393,955	Adcock Ingram Holdings (South Africa)		21,034
		Manufacturer of Pharmaceuticals & Medical Supplies
	1,818,154	Alimera Sciences (a)(b)(c)		14,818
		Ophthalmogy-focused Pharmaceutical Company
				63,852
		> Hospital Management 0.2%
	1,450,000	Kindred Healthcare (a)		31,131
		Post-Acute Healthcare Facilities
				31,131
Health Care: Total				1,659,569
Other Industries 5.8%
		> Real Estate 3.5%
	4,575,000	BioMed Realty Trust		88,023
		Life Science-focused Office Buildings
	840,000	Federal Realty Investment Trust		71,551
		Shopping Centers
	2,200,000	Dupont Fabros Technology (b)		55,440
		Technology-focused Office Buildings
	720,000	Digital Realty Trust (b)		44,481
		Technology-focused Office Buildings
	1,120,000	Kilroy Realty		44,229
		West Coast Office & Industrial Properties
	2,700,000	Associated Estates Realty (c)		43,875
		Multi-family Properties
	975,000	Post Properties		39,741
		Multi-family Properties
	1,850,000	Extra Space Storage		39,460
		Self Storage Facilities
	43,000,000	Mapletree Logistics Trust (Singapore)		32,243
		Industrial Property Landlord
	530,000	Macerich		28,355
		Regional Shopping Malls
	900,000	Corporate Office Properties		27,999
		Office Buildings

Number of Shares			Value (000)
	3,000,000	Education Realty Trust	$	25,710
		Student Housing
	15,000,000	Ascendas REIT (Singapore)		24,949
		Industrial Property Landlord
	700,000	Washington REIT		22,764
		Washington D.C. Diversified Properties
	3,750,000	DCT Industrial Trust		19,612
		Industrial Properties
	1,481,994	Summit Hotel Properties (c)		16,821
		Owner of Select Service Hotels
	2,800	Orix JREIT (Japan)		15,473
		Diversified REIT
	3,050,000	Kite Realty Group		15,189
		Community Shopping Centers
	699,701	St. Joe (a)		14,582
		Florida Panhandle Landowner
	37,407	Security Capital European Realty (Luxembourg) (a)(d)(e)		—
		Self Storage Properties
				670,497
		> Transportation 1.3%
	1,730,000	JB Hunt Transport Services		81,465
		Truck & Intermodal Carrier
	2,800,000	Rush Enterprises, Class A (a)(c)		53,284
	550,000	Rush Enterprises, Class B (a)(c)		8,855
		Truck Sales & Services
	1,260,000	World Fuel Services		45,272
		Global Fuel Broker
	2,730,000	Heartland Express		45,209
		Regional Trucker
	400,000	Genesee & Wyoming (a)		23,456
		Short-line Operator
				257,541
		> Regulated Utilities 1.0%
	2,000,000	Northeast Utilities		70,340
		Regulated Electric Utility
	1,800,000	Wisconsin Energy		56,430
		Wisconsin Utility
	500,000	ALLETE		20,520
		Regulated Electric Utility in Minnesota
	333,000	Red Eléctrica de España (Spain)		20,101
		Spanish Power Transmission
	3,333,000	Terna (Italy) (b)		15,496
		Italian Power Transmission
				182,887
Other Industries: Total				1,110,925
Total Equities: 97.5% (Cost: $11,304,342)				18,778,101
Securities Lending Collateral – 1.8%
	352,904	Dreyfus Government Cash Management Fund (f) (7 day yield of 0.00%)		352,904
Total Securities Lending Collateral: (Cost: $352,904)				352,904

See accompanying notes to financial statements.

32

Principal Amount			Value (000)
Short-Term Obligation 2.8%
		> Repurchase Agreement 2.8%
$	534,686	Repurchase Agreement with Fixed Income Clearing Corp., dated 6/30/11, due 7/01/11 at 0.01%, collateralized by U.S. Government Agency obligations with various maturities to 12/03/15, market value $545,385 (repurchase proceeds $534,686)	$	534,686
				534,686
Total Short-Term Obligation: (Amortized Cost: $534,686)				534,686
Total Investments: 102.1% (Cost: $12,191,932)(g)(h)				19,665,691
Obligation to Return Collateral for Securities Loaned: (1.8)%				(352,904	)
Cash and Other Assets Less Liabilities: (0.3)%				(60,928	)
Total Net Assets: 100.0%			$	19,251,859

ADR = American Depositary Receipts

GDR = Global Depository Receipts

See accompanying notes to financial statements.

33

Columbia Acorn Fund

Statement of Investments (Unaudited), 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 June 30, 2011. The total market value of Fund securities on loan at June 30, 2011 was $340,090.

(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 six months ended June 30, 2011, are as follows:

Affiliates	Balance of Shares Held 12/31/10		Purchases/ Additions		Sales/ Reductions		Balance of Shares Held 6/30/11		Value		Dividend
AFC Enterprises		2,000,000		-		-		2,000,000	$	32,900	$	-
Allos Therapeutics*		7,035,000		-		7,035,000		-		-		-
Alimera Sciences		361,450		1,456,704		-		1,818,154		14,818		-
Anthera Pharmaceuticals		1,450,000		290,000		-		1,740,000		14,216		-
Array Biopharma		3,500,000		-		-		3,500,000		7,840		-
Art Technology Group*		9,000,000		-		9,000,000		-		-		-
Associated Estates Realty		2,200,000		500,000		-		2,700,000		43,875		748
Auxilium Pharmaceuticals		1,200,000		1,200,000		-		2,400,000		47,040		-
Bally Technologies		3,725,000		-		-		3,725,000		151,533		-
Blackbaud		2,250,000		-		-		2,250,000		62,370		540
CAI International		1,650,000		-		526,600		1,123,400		23,209		-
Cavco Industries		180,000		235,000		-		415,000		18,675		-
Cepheid		2,415,000		785,000		-		3,200,000		110,848		-
Chelsea Therapeutics		3,449,900		1,100,000		-		4,549,900		23,205		-
Clarcor		2,565,000		-		-		2,565,000		121,273		539
Cogent Communications		2,800,000		-		280,000		2,520,000		42,865		-
Constant Contact		1,400,000		550,000		-		1,950,000		49,491		-
Diamond Foods		1,300,000		-		130,000		1,170,000		89,318		117
Donaldson		4,200,000		-		-		4,200,000		254,856		1,176
Drew Industries		1,260,000		-		-		1,260,000		31,147		-
Education Realty Trust*		3,000,000		-		-		3,000,000		25,710		300
eResearch Technology		4,250,000		-		-		4,250,000		27,073		-
ESCO Technologies		2,200,000		-		-		2,200,000		80,960		352
Gaiam		1,371,366		-		-		1,371,366		6,816		-
Gaylord Entertainment		3,850,000		-		-		3,850,000		115,500		-
H&E Equipment Services		3,000,000		-		-		3,000,000		41,970		-
Hackett Group		4,500,000		-		-		4,500,000		22,905		-
HEICO		1,700,000		550,000		-		2,250,000		89,460		102
Helen of Troy		1,600,000		-		-		1,600,000		55,248		-
iGate		2,913,065		-		13,065		2,900,000		47,328		-
II-VI		2,225,000		2,325,000		-		4,550,000		116,480		-
Informatica*		5,200,000		-		500,000		4,700,000		274,621		-
Interline Brands		2,600,000		-		-		2,600,000		47,762		-
IPG Photonics		2,710,000		70,000		-		2,780,000		202,134		-
IXYS		1,900,000		-		-		1,900,000		28,462		-
Kenexa		2,025,000		-		-		2,025,000		48,560		-
Knoll		4,000,000		-		-		4,000,000		80,280		640
Lifetime Fitness		2,190,000		-		-		2,190,000		87,403		-
lululemon athletica		4,035,000		-		43,735		3,991,265		446,304		-
Marlin Business Services		1,091,000		-		-		1,091,000		13,801		-
MB Financial		2,860,000		-		-		2,860,000		55,026		57
McGrath Rentcorp		2,350,000		-		-		2,350,000		65,988		1,069
Micromet		5,500,000		-		-		5,500,000		31,570		-
Nabi Biopharmaceuticals		1,383,454		1,916,546		-		3,300,000		17,754		-
Nanosphere*		1,480,056		-		1,480,056		-		-		-
Navigant Consulting		3,100,000		-		-		3,100,000		32,519		-
NPS Pharmaceuticals		3,200,000		1,300,000		-		4,500,000		42,525		-
Orko Silver*		10,000,000		-		5,000,000		5,000,000		14,464		-
Orthofix International*		1,150,000		-		580,000		570,000		24,208		-
PAETEC Holding		9,600,000		-		-		9,600,000		45,984		-
Pericom Semiconductor		1,765,000		-		-		1,765,000		15,779		-
Petroamerica		30,275,000		-		-		30,275,000		5,023		-
Petrodorado		48,000,000		2,000,000		-		50,000,000		10,658		-
Petrolifera Petroleum*		13,950,000		-		13,950,000		-		-		-
Petromanas		56,250,000		-		-		56,250,000		11,526		-
Pinnacle Entertainment		3,400,000		-		-		3,400,000		50,660		-

See accompanying notes to financial statements.

34

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

Affiliates	Balance of Shares Held 12/31/10		Purchases/ Additions		Sales/ Reductions		Balance of Shares Held 6/30/11		Value		Dividend
Quetzal Energy		-		50,000,000		-		50,000,000	$	4,011	$	-
Rush Enterprises		3,350,000		-		-		3,350,000		62,139		-
Salem Communications		1,541,000		-		-		1,541,000		5,532		-
Shutterfly		1,700,000		600,000		-		2,300,000		132,066		-
Spanish Broadcasting System		2,400,000		-		-		2,400,000		1,680		-
SPS Commerce		856,429		43,571		-		900,000		16,011		-
Summit Hotel Properties		-		1,481,994		-		1,481,994		16,821		61
Supertex		1,035,000		-		100,000		935,000		20,944		-
Talbots*		4,150,000		-		3,321,500		828,500		2,767		-
THQ*		3,567,000		-		3,567,000		-		-		-
TriCo Bancshares		1,350,000		-		-		1,350,000		19,710		243
True Religion Apparel		2,047,000		-		-		2,047,000		59,527		-
Tuscany International Drilling*+		13,319,200		4,589,700		7,349,700		10,559,200		9,118		-
tw telecom		9,500,000		-		-		9,500,000		195,035		-
Tyler Technologies		2,000,000		-		-		2,000,000		53,560		-
Universal Technical Institute		1,700,000		-		-		1,700,000		33,609		-
Virtusa		2,000,000		125,000		-		2,125,000		40,269		-
Warnaco Group*		2,190,000		-		-		2,190,000		114,427		-
Wolverine Minderals		-		6,000,000		-		6,000,000		2,670		-
World Acceptance		1,505,202		-		-		1,505,202		98,696		-
Total of Affiliated Transactions		358,776,122		77,118,515		52,876,656		383,017,981	$	4,310,532	$	5,944

*   At June 30, 2011, the Fund owned less than five percent of the company's outstanding voting shares.

+   Includes the effects of a corporate action.

  The aggregate cost and value of these companies at June 30, 2011, were $2,325,878 and $3,845,216, respectively. Investments in affiliated companies represented 20.0% of the Fund's total net assets at June 30, 2011.

(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 June 30, 2011, the market value of these securities amounted to $66,613, which represented 0.35% of total net assets.

  Additional information on these securities is as follows:

Security	Acquisition Dates	Shares		Cost		Value
Mail.ru - GDR	11/5/10-12/31/10		464,305	$	16,518	$	15,424
Union Agriculture Group	12/08/10		6,818,182		15,000		15,000
Petromanas	5/20/10		37,500,000		13,032		11,050
Canacol Energy	4/15/10		6,300,000		4,667		6,786
Tahoe Resources	5/28/10		236,400		1,350		4,368
Canadian Overseas Petroleum	11/24/10		8,400,000		3,591		3,884
Quetzal Energy	1/14/11		41,100,000		5,193		3,273
Petrodorado - Warrants	11/20/09		24,000,000		2,965		2,436
Wolverine Minerals	6/03/11		4,000,000		2,005		2,389
Canadian Overseas Petroleum - Warrants	11/24/10		4,200,000		526		572
Petromanas - Warrants	5/20/10		18,750,000		1,086		476
MicroDose Technologies	11/24/00		359,944		2,005		374
Voyager Learning, Contingent Value Rights	12/24/09		2,000,000		-		300
Wolverine Minerals - Warrants	6/03/11		2,000,000		243		281
Locus Pharmaceuticals	9/05/01-2/08/07		94,715		7,780		-
Security Capital European Realty	8/20/98-7/20/99		37,407		205		-
				$	76,166	$	66,613

(e)  Security has no value.

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

(g)  At June 30, 2011, for federal income tax purposes, the cost of investments was $12,191,932 and net unrealized appreciation was $7,473,759, consisting of gross unrealized appreciation of $8,160,875 and gross unrealized depreciation of $687,116.

See accompanying notes to financial statements.

35

Columbia Acorn Fund

Statement of Investments (Unaudited), continued

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

(h)  On June 30, 2011, the market value of foreign securities represented 10.80% of total net assets. The Fund's foreign portfolio was diversified as follows:

	Value		Percent
Netherlands	$	422,067		2.19
Canada		326,015		1.69
Colombia		174,245		0.91
Singapore		161,045		0.84
Hong Kong		132,474		0.69
Sweden		127,222		0.66
Japan		125,073		0.65
France		66,285		0.34
China		62,305		0.32
Brazil		61,705		0.32
Denmark		55,329		0.29
United Kingdon		52,219		0.27
South Africa		48,871		0.25
	Value		Percent
Chile	$	43,557		0.23
Ireland		34,204		0.18
Israel		29,088		0.15
Switzerland		24,109		0.13
India		22,513		0.12
Iraq		21,326		0.11
Spain		20,101		0.10
Italy		15,496		0.08
Russia		15,424		0.08
Argentina		15,000		0.08
Germany		11,984		0.06
Iceland		10,586		0.06
Luxembourg		-		0.00
Total Foreign Portfolio	$	2,078,243		10.80

  Various inputs are used in determining the value of the Fund's investments, following the input prioritization hierarchy established by GAAP. These inputs are summarized in the three broad levels listed below:

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

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

•  Level 3 – prices determined using significant unobservable inputs where quoted prices or observable inputs are unavailable or less reliable (including management's own assumptions about the factors market participants would use in pricing an investment)

  The inputs or methodology 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 Fund 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 Valuation Committee of the Fund's Board of Trustees that rely on significant observable inputs are also included in Level 2. Typical Level 3 securities include any security fair valued by the Valuation Committee that relies on significant unobservable inputs.

The following table summarizes the inputs used, as of June 30, 2011, 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	$	5,032,026	$	210,925	$	-	$	5,242,951
Consumer Goods & Services		3,382,164		148,575		300		3,531,039
Industrial Goods & Services		3,153,094		369,096		-		3,522,190
Energy & Minerals		1,502,348		368,333		15,000		1,885,681
Finance		1,821,981		3,765		-		1,825,746
Health Care		1,638,161		21,034		374		1,659,569
Other Industries		1,002,663		108,262		-		1,110,925
Total Equities		17,532,437		1,229,990		15,674		18,778,101
Total Securities Lending Collateral		352,904		-		-		352,904
Total Short-Term Obligation		-		534,686		-		534,686
Total Investments	$	17,885,341	$	1,764,676	$	15,674	$	19,665,691

  The Fund's assets assigned to the Level 2 input category are generally valued using a market approach, in which a security's value is determined through its correlation to prices and information from observable market transactions for similar or identical assets. Foreign equities are generally valued at the last sales price on the foreign exchange or market on which they trade. The Fund may use a systematic fair valuation model provided by an independent third party to value securities principally traded in foreign markets in order to adjust for possible stale pricing that may occur between the close of the foreign exchanges and the time for valuation. These models take into account available market data including intraday index, ADR, and ETF movements. Securities acquired via private placement that have a holding period or an extended settlement period are valued at a discount to the same shares that are trading freely on the market. These discounts are determined by the adviser's experience with similar securities or situations. Factors may include, but are not limited to, trade volume, shares outstanding and stock price. Warrants which do not trade are valued as a percentage of the actively trading common stock using a model based on Black Scholes.

See accompanying notes to financial statements.

36

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

  Certain short-term obligations may be valued using amortized cost, an income approach which converts future cash flows to a present value based upon the discount or premium at purchase.

  The Fund's assets assigned to the Level 3 input category are valued at fair value as determined in good faith under consistently applied procedures established by and under the general supervision of the Board of Trustees. To determine fair value, management will utilize the valuation technique that they deem the most appropriate in the circumstances. Securities acquired via private placement but are not yet trading are valued using the market approach for which management has determined that the original transaction price is the best representation of fair value. The original cost may be adjusted for the market movement in an index, ETF or similar security during the period it does not trade. Securities for which no market exist are valued based upon the market approach using some unobservable inputs which may include, but are not limited to, projected earnings, available cash, line of business, multiples, and consideration of the prioritization of the equity in a company's capital structure.

  The following table reconciles asset balances for the six months ending June 30, 2011, in which significant unobservable inputs (Level 3) were used in determining value:

Investments in Securities	Balance as of December 31, 2010		Realized Gain/(Loss)		Change in Unrealized Appreciation (Depreciation)		Purchases		Sales		Transfers into Level 3		Transfers out of Level 3		Balance as of June 30, 2011
Equities
Consumer Goods & Services	$	262	$	-	$	38	$	-	$	-	$	-	$	-	$	300
Energy & Minerals		15,000		-		-		-		-		-		-		15,000
Health Care		103		-		271		-		-		-		-		374
	$	15,365	$	-	$	309	$	-	$	-	$	-	$	-	$	15,674

  The information in the above reconciliation table represents fiscal year to date activity for any securities identified as using Level 3 inputs at either the beginning or the end of the current fiscal period.

  The change in unrealized appreciation attributed to securities owned at June 30, 2011, which were valued using significant unobservable inputs (Level 3) amounted to $309. This amount is included in net change in unrealized appreciation (depreciation) on the Statements of Changes in Net Assets.

  The following table shows transfers between Level 1 and Level 2 of the fair value hierarchy:

Transfers In				Transfers Out
Level 1		Level 2		Level 1		Level 2
$	54,754	$	-	$	-	$	54,754

  Financial assets were transferred from Level 2 to Level 1 as they resumed trading during the period.

  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.

37

Columbia Acorn International

Major Portfolio Changes in the Second Quarter (Unaudited)

	Number of Shares
	03/31/11		06/30/11
Purchases
Europe
> United Kingdom
GlobeOp Financial Services		3,100,000		3,758,000
JLT Group		2,147,000		2,868,800
Kesa Electricals		0		8,346,000
Next		0		582,000
Smith & Nephew		1,445,775		1,630,000
> Netherlands
Fugro		763,202		784,111
Imtech		1,803,729		1,841,280
USG People		1,079,600		1,093,994
> France
Gemalto		639,000		799,000
Teleperformance		670,000		1,078,000
> Germany
Dürr		0		237,511
Rhoen-Klinikum		1,110,000		1,460,000
> Switzerland
Dufry Group		0		190,000
Partners Group		185,000		235,000
> Norway
Atea		340,964		2,045,964
> Belgium
EVS Broadcast Equipment		0		145,031
Asia
> Japan
Asics		3,008,500		3,650,000
Hoshizaki Electric		1,532,300		1,563,000
Ibiden		711,000		819,000
Japan Airport Terminal		1,250,000		1,666,700
Kuraray		1,670,000		1,974,000
Shinsei Bank		13,353,800		23,908,800
Sintokogio		1,172,500		1,794,000
Torishima Pump Manufacturing		972,500		1,250,500
Ushio		1,170,800		1,292,500
> Singapore
Mapletree Commercial Trust		0		30,000,000
> Hong Kong
MGM China Holdings		0		12,000,000
Sa Sa International		33,000,000		35,000,000
> China
ENN Energy		0		6,000,000
Noah Holdings - ADR		223,100		432,790
Want Want		0		7,143,600

	Number of Shares
	03/31/11		06/30/11
> Taiwan
China Steel Chemical		2,966,500		4,192,000
Far Eastone Telecom		4,957,300		21,429,000
President Chain Store		3,362,500		5,665,000
St. Shine Optical		1,133,100		1,511,000
Taiwan Hon Chuan		4,639,400		6,911,000
> India
Jain Irrigation Systems		7,675,000		8,587,418
Mundra Port & Special Economic Zone		6,360,300		7,496,953
United Breweries		0		367,138
> Thailand
Home Product Center		58,207,800		80,000,000
> Indonesia
Ace Indonesia		0		6,898,100
Other Countries
> Canada
Alliance Grain Traders		0		501,700
Celtic Exploration		0		146,200
Crew Energy		0		367,600
> United States
Oil States International		0		250,000
> South Africa
Coronation Fund Managers		1,788,501		8,723,060
Rand Merchant Insurance		10,355,359		17,625,208
Latin America
> Brazil
Multiplus		0		1,100,000
> Colombia
Canacol Energy		8,058,800		8,240,000

See accompanying notes to financial statements.

38

	Number of Shares
	03/31/11		06/30/11
Sales
Europe
> United Kingdom
Cobham		9,259,000		5,385,000
FlyBe		1,462,658		1,376,083
Serco		6,700,000		3,513,800
> France
Eurofins Scientific		600,800		489,287
Toreador Resources		372,000		0
> Germany
CTS Eventim		490,000		403,286
Vossloh		240,000		165,000
> Sweden
East Capital Explorer		916,662		905,452
Hexagon		4,382,000		3,799,000
> Italy
Tod's		452,200		257,200
> Ireland
United Drug		12,110,000		9,669,485
> Finland
Poyry		1,706,942		410,523
Asia
> Japan
Benesse		33,300		0
Gree		2,226,000		1,355,000
Start Today		2,421,300		1,275,000
Suruga Bank		1,750,000		0
> Singapore
Mapletree Logistics Trust		57,000,000		50,000,000
> China
China Communication Services		45,000,000		41,959,300
China Green		10,140,400		0
China Yurun Food		12,199,600		10,764,600
Jiangsu Expressway		36,700,000		23,146,000
New Oriental Education & Technology - ADR		278,315		230,000
Wasion Group		29,425,300		24,244,400
Zuoan Fashion		817,360		680,503
> Taiwan
Formosa International Hotels		1,599,620		1,142,620
Simplo Technology		7,200,000		5,821,000
> India
Asian Paints		368,098		320,000
Housing Development Finance		1,100,000		0
Infrastructure Development Finance		5,675,000		3,550,000
Shriram Transport Finance		1,835,000		715,000

	Number of Shares
	03/31/11		06/30/11
Other Countries
> Canada
Baytex		735,000		574,000
Guyana Goldfields		1,355,000		1,291,135
> United States
Atwood Oceanics		1,340,000		1,273,000
Tesco		324,000		0
> Australia
Hastie Group		3,962,289		0
SAI Global		7,286,896		6,281,896
Latin America
> Brazil
Localiza Rent A Car		4,700,000		4,300,000
PDG Realty		5,000,000		4,400,000

See accompanying notes to financial statements.

39

Columbia Acorn International

Statement of Investments (Unaudited), June 30, 2011

Number of Shares			Value (000)
			Equities: 95.6%
Europe 37.4%
		> United Kingdom 7.0%
	2,000,000	Intertek Group	$	63,331
		Testing, Inspection & Certification Services
	5,437,000	Chemring		55,847
		Defense Manufacturer of Countermeasures & Energetics
	2,868,800	JLT Group		31,355
		International Business Insurance Broker
	3,513,800	Serco		31,158
		Facilities Management
	56,093,000	Workspace Group		27,233
		United Kingdom Real Estate
	26,712,371	Archipelago Resources (a)		26,474
		Gold Mining Projects in Indonesia, Vietnam & the Philippines
	3,758,000	GlobeOp Financial Services		23,613
		Hedge Fund Administrator
	1,976,000	Petropavlovsk		23,151
		Gold & Iron Ore Mining in Russia
	582,000	Next		21,717
		Clothes & Home Retailer in the United Kingdom
	8,346,000	Kesa Electricals		18,445
		Europe's Leading Electricals Retailers
	2,752,210	Abcam		18,409
		Online Sales of Antibodies
	680,000	Rotork		18,400
		Valve Actuators for Oil & Water Pipelines
	5,385,000	Cobham		18,288
		Aerospace Components
	2,432,000	Premier Oil (a)		17,432
		Oil & Gas Producer in Europe, Pakistan & Asia
	1,630,000	Smith & Nephew		17,397
		Medical Equipment & Supplies
	690,000	Tullow Oil		13,732
		Oil & Gas Producer
	859,200	Shaftesbury		7,281
		London Prime Retail REIT
	3,889,000	PureCircle (a)(b)		5,524
		Natural Sweeteners
	1,650,000	SKIL Ports & Logistics (a)		5,164
		Indian Container Port Project
	1,549,500	Sterling Resources (a)		2,651
	1,050,500	Sterling Resources (a)(c)		1,761
		Oil & Gas Exploration - Europe
	1,376,083	FlyBe (a)		4,064
		Largest European Regional Airline
				452,427
		> Netherlands 6.4%
	1,841,280	Imtech		65,125
		Electromechanical & Information & Communications Technologies Installation & Maintenance
	784,111	Fugro		56,536
		Sub-sea Oilfield Services

Number of Shares			Value (000)
	1,104,200	Vopak	$	54,106
		World's Largest Operator of Petroleum & Chemical Storage Terminals
	2,296,992	Aalberts Industries		53,695
		Flow Control & Heat Treatment
	1,476,800	Unit 4 Agresso (d)		53,390
		Business Software Development
	1,272,365	Koninklijke TenCate		51,516
		Advanced Textiles & Industrial Fabrics
	1,164,669	Arcadis		28,493
		Engineering Consultants
	249,000	Core Laboratories		27,773
		Oil & Gas Reservoir Consulting
	1,093,994	USG People		18,918
		Temporary Staffing Services
				409,552
		> France 5.1%
	610,000	Neopost		52,403
		Postage Meter Machines
	489,287	Eurofins Scientific		45,070
		Food, Pharmaceuticals & Materials Screening & Testing
	799,000	Gemalto		38,207
		Smart Card Products & Solutions
	274,100	Rubis		34,772
		Tank Storage & Liquefied Petroleum Gas Distribution
	1,078,000	Teleperformance		31,680
		Call Center Operator
	902,900	Saft		31,051
		Niche Battery Manufacturer
	541,500	Mersen		30,546
		Advanced Industrial Materials
	322,200	Pierre & Vacances		26,862
		Vacation Apartment Lets
	213,800	Norbert Dentressangle		25,265
		Leading European Logistics & Transport Group
	1,689,100	Hi-Media (a)		10,116
		Online Advertiser in Europe
				325,972
		> Germany 3.9%
	630,000	Rheinmetall		55,775
		Defense & Automotive
	2,120,000	Wirecard (b)		37,891
		Online Payment Processing & Risk Management
	137,500	Rational		36,240
		Commercial Ovens
	1,460,000	Rhoen-Klinikum		35,230
		Health Care Services
	403,286	CTS Eventim		27,867
		Event Ticket Sales
	165,000	Vossloh		23,157
		Rail Infrastructure & Diesel Locomotives
	515,000	Elringklinger		18,275
		Automobile Components

See accompanying notes to financial statements.

40

Number of Shares			Value (000)
		> Germany—continued
	237,511	Dürr	$	9,644
		Automotive Plant Engineering & Associated Capital Equipment
	312,500	Deutsche Beteiligungs		8,814
		Private Equity Investment Management
				252,893
		> Switzerland 3.7%
	22,300	Sika		53,764
		Chemicals for Construction & Industrial Applications
	325,000	Kuehne & Nagel		49,325
		Freight Forwarding/Logistics
	185,000	Geberit (a)		43,832
		Plumbing Supplies
	235,000	Partners Group		41,592
		Private Markets Asset Management
	720,000	Bank Sarasin & Cie		28,517
		Private Banking
	190,000	Dufry Group (a)		23,932
		Operates Airport Duty Free & Duty Paid Shops
				240,962
		> Sweden 2.6%
	3,799,000	Hexagon (b)		93,576
		Measurement Equipment & Software
	3,887,000	Sweco		38,254
		Engineering Consultants
	607,000	Unibet (a)		13,171
		European Online Gaming Operator
	905,452	East Capital Explorer		10,521
		Sweden-based RUS/CEE Investment Fund
	708,342	Orc Software (b)		9,435
		Software for Securities Trading, Analysis & Risk Management
				164,957
		> Italy 2.4%
	257,200	Tod's		34,407
		Leather Shoes & Bags
	2,083,000	Ansaldo STS		29,195
		Railway Systems Integrator
	4,311,600	Credito Emiliano		27,273
		Italian Regional Bank
	9,796,000	CIR		24,533
		Italian Holding Company
	3,573,000	Geox		21,410
		Apparel & Shoe Maker
	4,111,000	Terna (b)		19,113
		Italian Power Transmission
				155,931
		> Denmark 1.2%
	306,000	Novozymes		49,796
		Industrial Enzymes
	156,000	SimCorp		30,785
		Software for Investment Managers
				80,581

Number of Shares			Value (000)
		> Ireland 1.1%
	9,669,485	United Drug	$	33,121
		Irish Pharmaceutical Wholesaler & Outsourcer
	359,000	Paddy Power		19,517
		Irish Betting Services
	297,000	Aryzta		15,735
		Baked Goods
				68,373
		> Portugal 0.6%
	7,278,105	Redes Energéticas Nacionais		26,164
		Portuguese Power Transmission & Gas Transportation
	22,568,987	Banco Comercial Português (a)		13,419
		Largest Portuguese Banking Franchise
				39,583
		> Iceland 0.6%
	35,982,499	Marel (a)		38,090
		Largest Manufacturer of Poultry & Fish Processing Equipment
				38,090
		> Spain 0.5%
	579,000	Red Eléctrica de España		34,950
		Spanish Power Transmission
				34,950
		> Finland 0.5%
	967,777	Stockmann (b)		27,423
		Department Store & Fashion Retailer in Scandinavia & Russia
	410,523	Poyry		5,876
		Engineering Consultants
				33,299
		> Czech Republic 0.5%
	121,268	Komercni Banka (b)		29,574
		Leading Czech Republic Universal Bank
				29,574
		> Russia 0.4%
	764,506	Mail.ru - GDR (a)(c)		25,397
		Internet Social Networking & Games for Russian Speakers
				25,397
		> Norway 0.3%
	2,045,964	Atea		21,521
		Leading Nordic IT Hardware/Software Re-seller & Installation Company
				21,521
		> Greece 0.2%
	6,475,300	Intralot		13,803
		Lottery & Gaming Systems & Services
				13,803
		> Poland 0.2%
	893,900	Central European Distribution (a)		10,012
		Largest Spirits Company in Central & Eastern Europe
				10,012

See accompanying notes to financial statements.

41

Columbia Acorn International

Statement of Investments (Unaudited), continued

Number of Shares			Value (000)
		> Belgium 0.2%
	145,031	EVS Broadcast Equipment	$	9,818
		Digital Live Mobile Production Software & Systems
				9,818
Europe: Total				2,407,695
Asia 36.8%
		> Japan 16.2%
	7,568,400	Kansai Paint		68,957
		Paint Producer in Japan, India, China & Southeast Asia
	3,650,000	Asics		54,481
		Footwear & Apparel
	21,000	Seven Bank		41,964
		ATM Processing Services
	1,846,000	Aeon Delight		37,221
		Facility Maintenance & Management
	6,400	Orix JREIT		35,367
		Diversified REIT
	1,563,000	Hoshizaki Electric		34,695
		Commercial Kitchen Equipment
	15,300	Advance Residence Investment		32,022
		Residential REIT
	710,000	Hamamatsu Photonics		30,698
		Optical Sensors for Medical & Industrial Applications
	3,283,000	Kamigumi		30,682
		Port Cargo Handling & Logistics
	1,360,000	Asahi Diamond Industrial		29,733
		Consumable Diamond Tools
	1,355,000	Gree (a)		29,621
		Mobile Social Networking Game Developer/Platform
	707,000	Ain Pharmaciez		29,090
		Dispensing Pharmacy/Drugstore Operator
	1,974,000	Kuraray		28,919
		Special Resin, Fine Chemical, Fibers & Textures
	868,000	Kintetsu World Express		28,505
		Airfreight Logistics
	274,000	Nakanishi		28,232
		Dental Tools & Machinery
	23,500	Wacom (d)		27,443
		Computer Graphic Illustration Devices
	24,022	Jupiter Telecommunications		26,875
		Largest Cable Service Provider in Japan
	819,000	Ibiden		25,641
		Electronic Parts & Ceramics
	1,292,500	Ushio		25,556
		Industrial Light Sources
	1,275,000	Start Today		25,461
		Online Japanese Apparel Retailer
	789,000	Tsumura		25,223
		Traditional Chinese/Japanese Herbal Rx Drugs (Kampo)
	23,908,800	Shinsei Bank		23,915
		Commercial Bank
	1,181,200	Daiseki		23,914
		Waste Disposal & Recycling

Number of Shares			Value (000)
	509,000	Makita	$	23,719
		Power Tools
	5,100	Osaka Securities Exchange		22,766
		Osaka Securities Exchange
	7,174,000	Nippon Sheet Glass		22,306
		Sheet Glass for Building & Automotive Use
	977,000	Glory		22,006
		Currency Handling Systems & Related Equipment
	2,400,000	Shimadzu		21,982
		Analytical Instruments, Medical & Industrial Equipment
	906,000	Aeon Mall		21,948
		Suburban Shopping Mall Developer, Owner & Operator
	2,850	Fukuoka		21,457
		Diversified REIT in Fukuoka
	2,870	Kakaku.com		20,181
		Online Price Comparison Services for Consumers
	1,250,500	Torishima Pump Manufacturing		20,072
		Industrial Pump for Power Generation & Water Supply Systems
	1,666,700	Japan Airport Terminal		19,411
		Airport Terminal Operator at Haneda
	1,794,000	Sintokogio		18,418
		Automated Casting Machines, Surface Treatment Systems & Consumables
	675,780	Icom		17,390
		Two Way Radio Communication Equipment
	587,800	Miura		17,039
		Industrial Boiler Maker, Seller, Distributor & Manufacturer
	4,458	Mori Hills		16,313
		Tokyo Centric Diversified REIT
	439,800	Pigeon		14,456
		Baby Care Products
				1,043,679
		> Singapore 4.6%
	35,981,000	Olam International		79,986
		Agriculture Supply Chain Manager
	23,000,000	CDL Hospitality Trust		38,607
		Hotel Owner/Operator
	50,000,000	Mapletree Logistics Trust		37,491
		Industrial Property Landlord
	22,000,000	Ascendas REIT		36,592
		Industrial Property Landlord
	37,010,000	Mapletree Industrial Trust		35,291
		Industrial Property Landlord
	4,000,000	Singapore Exchange		24,580
		Singapore Equity & Derivatives Market Operator
	30,000,000	Mapletree Commercial Trust (a)		21,127
		Retail & Office Property Landlord
	13,000,000	Goodpack		19,391
		International Bulk Container Leasing
				293,065
		> Hong Kong 4.3%
	7,000,000	Melco Crown Entertainment - ADR (a)(b)		89,390
		Macau Casino Operator

See accompanying notes to financial statements.

42

Number of Shares			Value (000)
		> Hong Kong—continued
	18,000,000	Lifestyle International	$	53,125
		Mid- to High-end Department Store Operator in Hong Kong & China
	23,335,500	Mongolian Mining (a)		28,855
		Coking Coal Mining in Mongolia
	30,000,000	Hutchison Port Holdings Trust (a)		25,350
		Southern China Container Ports
	35,000,000	Sa Sa International		22,487
		Cosmetics Retailer
	12,000,000	MGM China Holdings (a)		22,144
		Macau Casino Operator
	8,077,000	L'Occitane International (a)		21,636
		Skin Care & Cosmetics Producer
	750,000	Hong Kong Exchanges and Clearing		15,802
		Hong Kong Equity & Derivatives Market Operator
				278,789
		> China 4.2%
	32,276,000	Zhaojin Mining Industry		66,584
		Gold Mining & Refining in China
	10,764,600	China Yurun Food		30,437
		Meat Processor in China
	230,000	New Oriental Education & Technology - ADR (a)		25,696
		Education Service Provider
	41,959,300	China Communication Services		24,845
		China's Telecom Infrastructure Service Provider
	240,000,000	RexLot Holdings		23,216
		Lottery Equipment Supplier in China
	23,146,000	Jiangsu Expressway		21,218
		Chinese Toll Road Operator
	6,000,000	ENN Energy		20,460
		China's Largest Private Gas Operator
	11,286,200	Shandong Weigao		16,385
		Vertically Integrated Hospital Consumable Manufacturing
	247,000	51job - ADR (a)		13,864
		An Integrated Human Resources Service Provider
	24,244,400	Wasion Group		11,413
		Electronic Power Meter Total Solution Provider
	7,143,600	Want Want		6,936
		Chinese Branded Consumer Food Company
	432,790	Noah Holdings - ADR (a)(b)		4,865
		Wealth Management Product Distributor in China
	680,503	Zuoan Fashion (a)(b)		3,804
		Men's Apparel Provider in China
				269,723
		> Taiwan 3.5%
	5,821,000	Simplo Technology		47,049
		World's Largest Notebook Battery Pack Supplier
	21,429,000	Far Eastone Telecom		34,202
		Taiwan's Third Largest Mobile Operator
	5,665,000	President Chain Store		32,821
		Taiwan's Number One Convenience Chain Store Operator

Number of Shares			Value (000)
	1,511,000	St. Shine Optical	$	22,957
		World's Leading Disposable Contact Lens OEM
	4,192,000	China Steel Chemical		22,456
		Sole Coal Chemical Producer in Taiwan
	1,142,620	Formosa International Hotels		21,674
		Hotel, Food & Beverage Operation & Hospitality Management Services
	6,911,000	Taiwan Hon Chuan		20,837
		Beverage Packaging (Bottles, Caps & Labels) Manufacturer
	7,206,000	Everlight Electronics		19,409
		LED Packager
	2,211,000	Sinyi Realty		4,270
		Taiwanese Realty Company
				225,675
		> India 2.4%
	8,587,418	Jain Irrigation Systems		32,834
		Agricultural Micro-irrigation Systems & Food Processing
	7,496,953	Mundra Port & Special Economic Zone		27,203
		Indian West Coast Shipping Port
	320,000	Asian Paints		22,666
		India's Largest Paint Company
	30,574,905	REI Agro		17,444
		Basmati Rice Processing
	11,814,746	Manappuram General Finance		14,896
		Short-term Lending Collateralized by Household Gold
	9,600,000	S. Kumars Nationwide (a)		11,654
		Textiles, Clothing & Retail
	3,550,000	Infrastructure Development Finance (a)		10,427
		Infrastructure Finance in India
	715,000	Shriram Transport Finance		9,892
		Used Truck Finance
	367,138	United Breweries		4,374
		India's Largest Brewer
				151,390
		> South Korea 1.3%
	1,157,000	Woongjin Coway		41,264
		South Korean Household Appliance Rental Service Provider
	150,000	NHN (a)		26,593
		South Korea's Largest Online Search Engine
	121,132	MegaStudy		16,295
		Education Service Provider
				84,152
		> Thailand 0.3%
	80,000,000	Home Product Center		21,351
		Home Improvement Retailer
				21,351
		> Indonesia —%
	6,898,100	Ace Indonesia		2,433
		Home Improvement Retailer
				2,433
Asia: Total				2,370,257

See accompanying notes to financial statements.

43

Columbia Acorn International

Statement of Investments (Unaudited), continued

Number of Shares			Value (000)
Other Countries 15.8%
		> Canada 5.3%
	1,710,000	ShawCor	$	52,517
		Oil & Gas Pipeline Products
	977,500	Ivanhoe Mines (a)		24,700
	855,600	Ivanhoe Mines (a)(e)		21,647
		Copper Mine Project in Mongolia
	1,301,612	CCL Industries		44,752
		Leading Global Label Manufacturer
	574,000	Baytex (b)		31,377
		Oil & Gas Producer in Canada
	540,000	AG Growth		25,644
		Leading Manufacturer of Augers & Grain Handling Equipment
	605,000	Onex Capital		23,442
		Private Equity Firm
	546,500	Black Diamond Group		17,849
		Provides Accommodations/Equipment for Oil Sands Exploitation
	872,700	Tahoe Resources (a)(c)		16,125
		Silver Project in Guatemala
	2,696,000	DeeThree Exploration (a)(c)(d)		9,862
	1,042,877	DeeThree Exploration (a)(d)		3,893
		Canadian Oil & Gas Producer
	501,700	Alliance Grain Traders		13,421
		Global Leader in Pulse Processing & Distribution
	2,214,100	Horizon North Logistics		10,285
		Provides Diversified Oil Service Offering in Northern Canada
	5,737,500	Southern Arc Minerals (a)(c)(d)		10,086
		Gold & Copper Exploration in Indonesia
	1,291,135	Guyana Goldfields (a)		9,170
		Gold Mining Projects in Guyana
	1,480,610	Pan Orient (a)		8,229
		Growth Oriented & Return Focused Asian Explorer
	367,600	Crew Energy (a)		5,717
		Canadian Oil & Gas Producer
	12,500,000	Eacom Timber (a)(c)		3,937
		Canadian Lumber Producer
	12,500,000	Petromanas (a)(c)		3,683
	6,250,000	Petromanas - Warrants (a)(c)		159
		Exploring for Oil in Albania
	146,200	Celtic Exploration (a)		3,233
		Canadian Oil & Gas Producer
				339,728
		> United States 3.8%
	1,273,000	Atwood Oceanics (a)		56,177
		Offshore Drilling Contractor
	822,000	Alexion Pharmaceuticals (a)		38,659
		Biotech Focused on Orphan Diseases
	918,000	World Fuel Services		32,984
		Global Fuel Broker
	1,145,000	BioMarin Pharmaceutical (a)		31,155
		Biotech Focused on Orphan Diseases
	658,000	FMC Technologies (a)		29,472
		Oil & Gas Wellhead Manufacturer

Number of Shares			Value (000)
	250,000	Oil States International (a)	$	19,978
		Diversified North American Oil Service Provider
	391,000	Bristow		19,949
		Largest Provider of Helicopter Services to Offshore Oil & Gas Producers
	568,000	Textainer Group Holdings		17,460
		Top International Container Leasor
				245,834
		> South Africa 3.8%
	1,096,000	Naspers		61,909
		Media in Africa, China, Russia & Other Emerging Markets
	4,600,000	Mr. Price		46,396
		South African Retailer of Apparel, Household & Sporting Goods
	4,625,000	Adcock Ingram Holdings		40,636
		Manufacturer of Pharmaceuticals & Medical Supplies
	5,780,900	Northam Platinum		36,309
		Platinum Mining in South Africa
	17,625,208	Rand Merchant Insurance		32,191
		Directly Sold Property & Casualty Insurance; Holdings in Other Insurers
	8,723,060	Coronation Fund Managers		24,898
		South African Fund Manager
				242,339
		> Australia 1.7%
	2,482,000	UGL		37,092
		Engineering & Facilities Management
	467,000	Cochlear		36,145
		Cochlear Implants
	6,281,896	SAI Global		32,009
		Publishing, Certification & Compliance Services
	1,000,000	Seek		6,936
		Online Job Listing & Education
				112,182
		> Israel 0.7%
	2,890,000	Israel Chemicals		46,119
		Producer of Potash, Phosphates, Bromine & Specialty Chemicals
				46,119
		> Kazakhstan 0.3%
	1,770,000	Halyk Savings Bank of Kazakhstan - GDR (a)		15,841
		Largest Retail Bank & Insurer in Kazakhstan
				15,841
		> Senegal 0.2%
	43,000	Sonatel (f)		13,784
		Leading Telecoms Operator in Western Africa
				13,784
		> Egypt —%
	235,342	Paints & Chemical Industries (Pachin)		1,509
		Paints & Inks in Egypt
				1,509
Other Countries: Total				1,017,336

See accompanying notes to financial statements.

44

Number of Shares			Value (000)
Latin America 5.6%
		> Brazil 4.2%
	4,300,000	Localiza Rent A Car	$	76,872
		Car Rental
	3,000,000	Mills Estruturas e Serviços de Engenharia		43,251
		Civil Engineering & Construction
	5,937,000	Suzano		42,949
		Brazilian Pulp & Paper Producer
	1,300,000	Natura		32,487
		Direct Retailer of Cosmetics
	3,400,000	MRV Engenharia		28,234
		Brazilian Property Developer
	4,400,000	PDG Realty		24,782
		Brazilian Property Developer
	1,100,000	Multiplus		19,172
		Loyalty Program Operator in Brazil
				267,747
		> Mexico 0.5%
	580,000	Grupo Aeroportuario del Sureste - ADR		34,185
		Mexican Airport Operator
				34,185
		> Chile 0.4%
	340,000	Sociedad Quimica y Minera de Chile - ADR (b)		22,005
		Producer of Specialty Fertilizers, Lithium & Iodine
				22,005
		> Argentina 0.3%
	6,818,182	Union Agriculture Group (a)(c)		15,000
		Farmland Operator in Uruguay
	5,400,000	Madalena Ventures (a)(c)		3,128
		Oil & Gas Exploration in Argentina
				18,128
		> Colombia 0.2%
	8,240,000	Canacol Energy (a)		9,056
		Oil Producer in South America
	20,718,000	Gulf United (a)(c)		6,091
		Prospecting for Oil Alongside Large Producers in Colombia
				15,147
Latin America: Total				357,212
Total Equities: 95.6% (Cost: $4,331,138)				6,152,500
		Securities Lending Collateral: 1.4%
	90,620,846	Dreyfus Government Cash Management Fund (g) (7 day yield of 0.00%)		90,621
Total Securities Lending Collateral: (Cost: $90,621)				90,621

Principal Amount (000)			Value (000)
Short-Term Obligation 3.5%
		> Repurchase Agreement 3.5%
$	226,923	Repurchase Agreement with Fixed Income Clearing Corp., dated 6/30/11, due 7/01/11 at 0.01%, collateralized by U.S. Government Agency obligations with various maturities to 9/08/17, market value $231,463 (repurchase proceeds $226,923)	$	226,923
				226,923
Total Short-Term Obligation: (Cost: $226,923)				226,923
Total Investments: 100.5% (Cost: $4,648,682)(h)(i)				6,470,044
Obligation to Return Collateral for Securities Loaned: (1.4)%				(90,621	)
Cash and Other Assets Less Liabilities: 0.9%				60,237
Total Net Assets: 100.0%			$	6,439,660

ADR = American Depositary Receipts

GDR = Global Depositary Receipts

See accompanying notes to financial statements.

45

Columbia Acorn International

Statement of Investments (Unaudited), continued

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

(a)  Non-income producing security.

(b)  All or a portion of this security was on loan at June 30, 2011. The total market value of Fund securities on loan at June 30, 2011 was $88,468.

(c)  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 June 30, 2011, the market value of these securities amounted to $95,229, which represented 1.48% of total net assets.

  Additional information on these securities is as follows:

Security	Acquisition Dates	Shares		Cost		Value
Mail.ru - GDR	11/05/10-12/31/10		764,506	$	26,088	$	25,397
Tahoe Resources	5/28/10		872,700		4,984		16,125
Union Agriculture Group	12/08/10		6,818,182		15,000		15,000
Southern Arc Minerals	2/16/11		5,737,500		9,308		10,086
DeeThree Exploration	9/07/10-3/08/11		2,696,000		9,486		9,862
Gulf United	2/11/11		20,718,000		6,215		6,091
Eacom Timber	3/17/10		12,500,000		6,188		3,937
Petromanas	5/20/10		12,500,000		4,344		3,683
Madalena Ventures	10/21/10		5,400,000		3,422		3,128
Sterling Resources	12/02/10		1,050,500		3,135		1,761
Petromanas - Warrants	5/20/10		6,250,000		362		159
				$	88,532	$	95,229

(d)  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 six months ended June 30, 2011, are as follows:

Affiliates	Balance of Shares Held 12/31/10		Purchases/ Additions		Sales/ Reductions		Balance of Shares Held 6/30/11		Value		Dividend
DeeThree Exploration		2,392,877		1,346,000		-		3,738,877	$	13,755	$	-
Gulf United*		-		20,718,000		-		20,718,000		6,091		-
Southern Arc Minerals		-		5,737,500		-		5,737,500		10,086		-
Unit 4 Aggresso		1,476,800		-		-		1,476,800		53,390		450
United Drug*		12,110,000		-		2,440,515		9,669,485		33,121		1,013
Wacom		20,900		2,600		-		23,500		27,443		721
Workspace Group*		60,304,000		-		4,211,000		56,093,000		27,233		213
Total of Affiliated Transactions		76,304,577		27,804,100		6,651,515		97,457,162	$	171,119	$	2,397

*  At June 30, 2011, the Fund owned less than five percent of the company's outstanding voting shares.

  The aggregate cost and value of these affiliated companies at June 30, 2011, was $85,252 and $104,674, respectively. Investments in affiliated companies represented 1.6% of total net assets at June 30, 2011.

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

(f)  Illiquid security.

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

(h)  At June 30, 2011, for federal income tax purposes, the cost of investments was $4,648,682 and net unrealized apppreciation was $1,821,362, consisting of gross unrealized appreciation of $2,050,001 and gross unrealized depreciation of $228,639.

(i)  On June 30, 2011, the Fund's total investments were denominated in currencies as follows:

Currency	Value		Percentage of Net Assets
Euro	$	1,316,400		20.4
Japanese Yen		1,043,679		16.2
U.S. Dollar		904,297		14.0
British Pound		448,015		7.0
Hong Kong Dollar		385,544		6.0
Canadian Dollar		334,678		5.2
Other currencies less than 5% of total net assets		2,037,431		31.7
	$	6,470,044		100.5

See accompanying notes to financial statements.

46

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

  At June 30, 2011, the Fund had entered into the following forward foreign currency exchange contracts:

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 Appreciation
AUD		USD		40,296	$	42,000	7/15/11	$	1,165
AUD		USD		1,408		1,500	7/15/11		8
AUD		USD		38,544		40,500	8/15/11		627
AUD		USD		1,414		1,500	8/15/11		8
AUD		USD		39,736		42,000	9/15/11		234
CAD		USD		1,937		2,000	7/15/11		8
CAD		USD		3,876		4,000	7/15/11		18
CAD		USD		45,558		47,000	8/15/11		188
CAD		USD		3,879		4,000	8/15/11		18
CAD		USD		49,493		51,000	9/15/11		226
EUR		USD		3,877		5,500	7/15/11		120
JPY		USD		999,744		12,000	7/15/11		419
JPY		USD		484,386		6,000	8/15/11		18
					$	259,000		$	3,057
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
USD	AUD			1,422	$	1,500	7/15/11	$	(23	)
CAD	USD			43,344		45,000	7/15/11		(70	)
USD	EUR			68,493		99,000	7/15/11		(297	)
USD	EUR			4,150		6,000	7/15/11		(16	)
USD	EUR			65,972		93,500	8/15/11		(2,060	)
USD	EUR			4,154		6,000	8/15/11		(17	)
USD	EUR			68,953		99,500	9/15/11		(290	)
USD	JPY			484,482		6,000	7/15/11		(18	)
JPY	USD			40,220		500	7/15/11		-	*
JPY	USD			40,214		500	8/15/11		-	*
JPY	USD			522,691		6,500	9/15/11		(5	)
					$	364,000		$	(2,796	)

*  Rounds to less than $500.

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

  Various inputs are used in determining the value of the Fund's investments, following the input prioritization hierarchy established by GAAP. These inputs are summarized in the three broad levels listed below:

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

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

•  Level 3 – prices determined using significant unobservable inputs where quoted prices or observable inputs are unavailable or less reliable (including management's own assumptions about the factors market participants would use in pricing an investment)

  The inputs or methodology 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 Fund 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 Valuation Committee of the Fund's Board of Trustees that rely on significant observable inputs are also included in Level 2. Typical Level 3 securities include any security fair valued by the Valuation Committee that relies on significant unobservable inputs.

See accompanying notes to financial statements.

47

Columbia Acorn International

Statement of Investments (Unaudited), continued

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

The following table summarizes the inputs used, as of June 30, 2011, 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	$	65,833	$	2,341,862		$	-	$	2,407,695
Asia		162,969		2,207,288			-		2,370,257
Other Countries		541,710		475,626			-		1,017,336
Latin America		332,993		9,219			15,000		357,212
Total Equities		1,103,505		5,033,995			15,000		6,152,500
Total Securities Lending Collateral		90,621		-			-		90,621
Total Short-Term Obligation		-		226,923			-		226,923
Total Investments	$	1,194,126	$	5,260,918		$	15,000	$	6,470,044
Unrealized Appreciation on Forward Foreign Currency Exchange Contracts		-		3,057			-		3,057
Unrealized Depreciation on Forward Foreign Currency Exchange Contracts		-		(2,796	)		-		(2,796	)
Total	$	1,194,126	$	5,261,179		$	15,000	$	6,470,305

  The Fund's assets assigned to the Level 2 input category are generally valued using a market approach, in which a security's value is determined through its correlation to prices and information from observable market transactions for similar or identical assets. Foreign equities are generally valued at the last sales price on the foreign exchange or market on which they trade. The Fund may use a systematic fair valuation model provided by an independent third party to value securities principally traded in foreign markets in order to adjust for possible stale pricing that may occur between the close of the foreign exchanges and the time for valuation. These models take into account available market data including intraday index, ADR, and ETF movements. Forward foreign currency exchange contracts are valued at the prevailing forward exchange rate of the underlying currencies. Securities acquired via private placement that have a holding period or an extended settlement period are valued at a discount to the same shares that are trading freely on the market. These discounts are determined by the adviser's experience with similar securities or situations. Factors may include, but are not limited to, trade volume, shares outstanding and stock price.

  Certain short-term obligations may be valued using amortized cost, an income approach which converts future cash flows to a present value based upon the discount or premium at purchase.

  The Fund's assets assigned to the Level 3 input category are valued at fair value as determined in good faith under consistently applied procedures established by and under the general supervision of the Board of Trustees. To determine fair value, management will utilize the valuation technique that they deem the most appropriate in the circumstances. Securities acquired via private placement that are not yet trading are valued using a market approach for which management has determined that the original transaction price is the best representation of fair value. The original cost may be adjusted for the market movement in an index, ETF or similar security during the period it does not trade.

The following table shows transfers between Level 1 and Level 2 of the fair value hierarchy.

Transfers In				Transfers Out
Level 1		Level 2		Level 1		Level 2
$	263,663	$	13,490	$	13,490	$	263,663

  Financial assets were transferred from Level 2 to Level 1 as they resumed trading during the period.

  Foreign exchange-traded financial assets were transferred from Level 1 to Level 2.

  The following table reconciles asset balances for the six months ending June 30, 2011, in which significant unobservable inputs (Level 3) were used in determining value:

Investments in Securities	Balance as of December 31, 2010		Realized Gain/(Loss)			Change in Unrealized Appreciation (Depreciation)		Purchases		Sales		Transfers into Level 3		Transfers out of Level 3		Balance as of June 30, 2011
Equities
Asia	$	79	$	(38,558	)	$	38,479	$	-	$	-	$	-	$	-	$	-
Latin America		15,000		-			-		-		-		-		-		15,000
	$	15,079	$	(38,558	)	$	38,479	$	-	$	-	$	-	$	-	$	15,000

  The information in the above reconciliation table represents fiscal year to date activity for any securities identified as using Level 3 inputs at either the beginning or the end of the current fiscal period.

  The change in unrealized appreciation (depreciation) attributed to securities owned at June 30, 2011, which were valued using significant unobservable inputs (Level 3) amounted to $38,479. This amount is included in net change in unrealized appreciation (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.

48

Columbia Acorn International

Portfolio Diversification (Unaudited)

At June 30, 2011, 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	$	541,127		8.4
Machinery		469,283		7.3
Industrial Materials & Specialty Chemicals		459,670		7.1
Electrical Components		130,742		2.0
Conglomerates		103,870		1.6
Construction		87,084		1.4
Outsourcing Services		50,077		0.8
Industrial Distribution		19,391		0.3
		1,861,244		28.9
> Consumer Goods & Services
Retail		247,635		3.9
Food & Beverage		189,620		2.9
Casinos & Gaming		181,242		2.8
Nondurables		147,738		2.3
Apparel		118,771		1.8
Other Consumer Services		112,523		1.7
Travel		107,797		1.7
Other Entertainment		49,541		0.8
Educational Services		41,991		0.7
Consumer Goods Distribution		18,445		0.3
		1,215,303		18.9
> Energy & Minerals
Mining		290,874		4.5
Oil Services		262,762		4.1
Oil & Gas Producers		120,004		1.8
Oil Refining, Marketing & Distribution		88,879		1.4
Agricultural Commodities		75,308		1.2
		837,827		13.0
> Information
Instrumentation		146,256		2.3
Internet Related		141,016		2.2
Computer Hardware & Related Equipment		112,699		1.8
Business Software		93,992		1.5
Financial Processors		78,273		1.2
Mobile Communications		51,592		0.8
Telephone and Data Services		45,463		0.7
Computer Services		30,956		0.5
Gaming Equipment & Services		29,621		0.5
CATV		26,875		0.4
Telecommunications Equipment		24,845		0.4
Semiconductors & Related Equipment		19,409		0.3
Advertising		10,116		0.2
		811,113		12.8

	Value (000)			Percentage of Net Assets
> Other Industries
Real Estate	$	361,797			5.6
Transportation		163,746			2.5
Regulated Utilities		100,687			1.6
		626,230			9.7
> Finance
Banks		162,412			2.5
Brokerage & Money Management		137,955			2.1
Finance Companies		93,321			1.5
Insurance		63,547			1.0
		457,235			7.1
> Health Care
Medical Equipment & Devices		136,817			2.1
Pharmaceuticals		98,980			1.5
Medical Supplies		41,365			0.6
Health Care Services		35,231			0.5
Biotechnology & Drug Delivery		31,155			0.5
		343,548			5.2
Total Equities:		6,152,500			95.6
Securities Lending Collateral:		90,621			1.4
Short-Term Obligation:		226,923			3.5
Total Investments:		6,470,044			100.5
Obligation to Return Collateral for Securities Loaned:		(90,621	)		(1.4	)
Cash and Other Assets Less Liabilities:		60,237			0.9
Net Assets:	$	6,439,660			100.0

See accompanying notes to financial statements.

49

Columbia Acorn USA

Major Portfolio Changes in the Second Quarter (Unaudited)

	Number of Shares
	03/31/11		06/30/11
Purchases
Consumer Goods & Services
HomeAway		0		30,000
Industrial Goods & Services
Drew Industries		326,000		496,000
ESCO Technologies		735,000		835,000
HEICO		403,732		504,665
Nordson		373,600		747,200
Finance
Enstar Group		0		39,000
Hancock Holding		40,000		278,678
TrustCo Bank		0		245,300
Health Care
Akorn		676,582		725,000
Auxilium Pharmaceuticals		205,000		375,000
Community Health Systems		0		151,000
Isis Pharmaceuticals		626,000		850,000
Kindred Healthcare		0		150,000
United Therapeutics		65,000		102,000
Energy & Minerals
FMC Technologies		500,000		1,000,000
Swift Energy		84,000		168,000
Other Industries
Rush Enterprises, Class A		210,091		410,091

	Number of Shares
	03/31/11		06/30/11
Sales
Information
Acxiom		172,000		0
Blue Coat Systems		197,000		0
Crown Castle International		150,000		0
Equinix		44,000		0
SRA International		261,000		0
Supertex		177,266		0
Consumer Goods & Services
Chico's FAS		614,000		481,000
Express		104,508		0
ITT Educational Services		153,700		37,350
Knoll		980,000		880,000
Vail Resorts		150,000		71,000
Wet Seal		620,000		0
Industrial Goods & Services
American Reprographics		396,000		0
Mueller Water Products		550,000		204,200
Finance
GATX		240,000		42,400
Investment Technology Group		139,400		0
Tower Group		222,000		0
Valley National Bancorp		981,941		931,000
Whitney Holding		571,000		0
Wilmington Trust		245,000		0
Health Care
Allos Therapeutics		446,532		0
American Medical Systems		72,000		0
Idenix Pharmaceuticals		428,965		0
Nektar Therapeutics		146,710		0
Energy & Minerals
Atwood Oceanics		845,000		803,000
Carrizo Oil & Gas		146,000		73,000
Hornbeck Offshore		101,000		0
Tesco		53,000		0

See accompanying notes to financial statements.

50

Columbia Acorn USA

Statement of Investments (Unaudited), June 30, 2011

Number of Shares			Value (000)
			Equities: 99.4%
Information 34.1%
		> Business Software 9.7%
	985,000	Informatica (a)	$	57,554
		Enterprise Data Integration Software
	698,000	Micros Systems (a)		34,698
		Information Systems for Hotels, Restaurants & Retailers
	375,000	ANSYS (a)		20,501
		Simulation Software for Engineers & Designers
	408,000	Ariba (a)		14,064
		Cost Management Software
	243,000	Concur Technologies (a)		12,167
		Web Enabled Cost & Expense Management Software
	247,000	Blackboard (a)(b)		10,717
		Education Software
	333,000	Blackbaud		9,231
		Software & Services for Non-profits
	220,000	Advent Software (a)		6,197
		Asset Management & Trading Systems
	322,000	SPS Commerce (a)		5,728
		Supply Chain Management Software Delivered via the Web
	129,000	NetSuite (a)		5,057
		End to End IT Systems Solutions Delivered Over the Web
	198,000	Constant Contact (a)		5,025
		E-mail & Other Marketing Campaign Management Systems Delivered Over the Web
	52,000	Quality Systems		4,540
		IT Systems for Medical Groups & Ambulatory Care Centers
				185,479
		> Instrumentation 4.7%
	678,000	IPG Photonics (a)		49,297
		Fiber Lasers
	180,000	Mettler Toledo (a)		30,361
		Laboratory Equipment
	168,000	Trimble Navigation (a)		6,660
		GPS-based Instruments
	130,000	FLIR Systems		4,382
		Infrared Cameras
				90,700
		> Semiconductors & Related Equipment 4.4%
	1,958,000	Atmel (a)		27,549
		Microcontrollers, Radio Frequency & Memory Semiconductors
	760,000	Microsemi (a)		15,580
		Analog/Mixed-signal Semiconductors
	1,061,750	ON Semiconductor (a)		11,117
		Mixed-signal & Power Management Semiconductors
	1,075,000	TriQuint Semiconductor (a)		10,954
		Radio Frequency Semiconductors
	675,000	Entegris (a)		6,831
		Semiconductor Materials Management Products

Number of Shares			Value (000)
	346,000	Monolithic Power Systems (a)	$	5,336
		High Performance Analog & Mixed-signal Integrated Circuits (ICs)
	448,000	Applied Micro Circuits (a)		3,969
		Communications Semiconductors
	430,000	Pericom Semiconductor (a)		3,844
		Interface Integrated Circuits (ICs) & Frequency Control Products
				85,180
		> Computer Hardware & Related Equipment 3.9%
	1,238,000	II-VI (a)		31,693
		Laser Optics & Specialty Materials
	324,000	Zebra Technologies (a)		13,663
		Bar Code Printers
	196,000	Amphenol		10,582
		Electronic Connectors
	280,000	Nice Systems - ADR (Israel) (a)		10,181
		Audio & Video Recording Solutions
	196,000	Netgear (a)		8,569
		Networking Products for Small Business & Home
				74,688
		> Telephone and Data Services 2.9%
	1,617,000	tw telecom (a)		33,197
		Fiber Optic Telephone/Data Services
	168,800	AboveNet		11,893
		Metropolitan Fiber Communications Services
	2,030,000	PAETEC Holding (a)		9,724
		Telephone/Data Services for Business
				54,814
		> Telecommunications Equipment 2.9%
	386,000	Polycom (a)		24,820
		Video Conferencing Equipment
	732,000	Finisar (a)		13,198
		Optical Sub-systems & Components
	903,000	Ixia (a)		11,558
		Telecom Network Test Equipment
	752,000	Infinera (a)		5,196
		Optical Networking Equipment
				54,772
		> Gaming Equipment & Services 1.8%
	660,000	Bally Technologies (a)		26,849
		Slot Machines & Software
	235,000	WMS Industries (a)		7,219
		Slot Machine Provider
				34,068
		> Mobile Communications 1.3%
	650,000	SBA Communications (a)		24,824
		Communications Towers
				24,824
		> Computer Services 1.0%
	428,000	ExlService Holdings (a)		9,887
		BPO (Business Process Outsourcing)
	1,005,500	Hackett Group (a)		5,118
		IT Integration & Best Practice Research

See accompanying notes to financial statements.

51

Columbia Acorn USA

Statement of Investments (Unaudited), continued

Number of Shares			Value (000)
		> Computer Services—continued
	710,000	RCM Technologies (a)(c)	$	3,798
		Technology & Engineering Services
				18,803
		> Financial Processors 0.5%
	188,000	Global Payments		9,588
		Credit Card Processor
				9,588
		> Contract Manufacturing 0.5%
	261,000	Plexus (a)		9,085
		Electronic Manufacturing Services
				9,085
		> Entertainment Programming 0.2%
	145,000	IMAX (Canada) (a)		4,702
		IMAX Movies, Theatre Equipment & Theatre Joint Ventures
				4,702
		> Radio 0.1%
	511,100	Salem Communications		1,835
		Radio Stations for Religious Programming
	71,718	Spanish Broadcasting System (a)		50
		Spanish Language Radio Stations
				1,885
		> TV Broadcasting 0.1%
	975,000	Entravision Communications (a)		1,804
		Spanish Language TV & Radio Stations
				1,804
		> Internet Related 0.1%
	343,000	TheStreet.com		1,053
		Financial Information Websites
				1,053
Information: Total				651,445
Consumer Goods & Services 16.9%
		> Retail 6.2%
	390,000	lululemon athletica (a)		43,610
		Premium Active Apparel Retailer
	468,500	Abercrombie & Fitch		31,352
		Teen Apparel Retailer
	254,000	Shutterfly (a)		14,585
		Internet Photo-centric Retailer
	875,000	Saks (a)		9,774
		Luxury Department Store Retailer
	805,000	Pier 1 Imports (a)		9,314
		Home Furnishing Retailer
	481,000	Chico's FAS		7,325
		Women's Specialty Retailer
	480,000	Talbots (a)(b)		1,603
		Women's Specialty Retailer
	9,000	The Fresh Market (a)		348
		Specialty Food Retailer
				117,911
		> Travel 3.2%
	849,700	Gaylord Entertainment (a)		25,491
		Convention Hotels

Number of Shares			Value (000)
	1,175,950	Avis Budget Group (a)	$	20,097
		Second Largest Car Rental Company
	750,000	Hertz (a)		11,910
		Largest U.S. Rental Car Operator
	71,000	Vail Resorts		3,282
		Ski Resort Operator & Developer
	30,000	HomeAway (a)		1,161
		Vacation Rental Online Marketplace
				61,941
		> Furniture & Textiles 1.9%
	880,000	Knoll		17,662
		Office Furniture
	540,000	Interface		10,460
		Modular & Broadloom Carpet
	260,000	Herman Miller		7,077
		Office Furniture
				35,199
		> Apparel 1.3%
	192,000	Warnaco Group (a)		10,032
		Global Branded Apparel Manufacturer
	90,000	Deckers Outdoor (a)		7,932
		Fashion Footwear Wholesaler
	241,530	True Religion Apparel (a)		7,024
		Premium Denim
				24,988
		> Casinos & Gaming 1.1%
	270,000	Penn National Gaming (a)		10,892
		Regional Casino Operator
	645,000	Pinnacle Entertainment (a)		9,610
		Regional Casino Operator
				20,502
		> Food & Beverage 0.8%
	197,000	Diamond Foods (b)		15,039
		Snack Foods & Culinary Ingredients
				15,039
		> Consumer Goods Distribution 0.7%
	472,000	Pool		14,070
		Distributor of Swimming Pool Supplies & Equipment
				14,070
		> Other Durable Goods 0.6%
	161,000	Cavco Industries (a)		7,245
		Manufactured Homes
	140,000	Jarden		4,831
		Branded Household Products
				12,076
		> Other Consumer Services 0.5%
	259,000	Lifetime Fitness (a)		10,337
		Sport & Fitness Club Operator
				10,337
		> Educational Services 0.3%
	165,000	Universal Technical Institute		3,262
		Vocational Training
	37,350	ITT Educational Services (a)		2,922
		Post-secondary Degree Services
				6,184

See accompanying notes to financial statements.

52

Number of Shares			Value (000)
		> Leisure Products 0.3%
	162,000	Thor Industries	$	4,672
		RV & Bus Manufacturer
				4,672
		> Restaurants —%
	26,600	Bravo Brio Restaurant Group (a)		650
		Upscale Casual Italian Restaurants
				650
Consumer Goods & Services: Total				323,569
Industrial Goods & Services 15.1%
		> Machinery 11.6%
	941,250	Ametek		42,262
		Aerospace/Industrial Instruments
	747,200	Nordson		40,984
		Dispensing Systems for Adhesives & Coatings
	835,000	ESCO Technologies		30,728
		Automatic Electric Meter Readers
	445,000	Donaldson		27,003
		Industrial Air Filtration
	585,000	Pentair		23,611
		Pumps & Water Treatment
	504,665	HEICO		20,065
		FAA Approved Aircraft Replacement Parts
	280,000	MOOG (a)		12,186
		Motion Control Products for Aerospace, Defense & Industrial Markets
	177,000	Kennametal		7,471
		Consumable Cutting Tools
	100,000	WABCO Holdings (a)		6,906
		Truck & Bus Component Supplier
	162,000	Oshkosh (a)		4,688
		Specialty Truck Manufacturer
	71,800	Toro		4,344
		Turf Maintenance Equipment
	50,000	Kaydon		1,866
		Specialized Friction & Motion Control Products
				222,114
		> Industrial Materials & Specialty Chemicals 1.0%
	496,000	Drew Industries		12,261
		RV & Manufactured Home Components
	54,000	Albemarle		3,737
		Refinery Catalysts & Other Specialty Chemicals
	135,000	Albany International		3,563
		Paper Machine Clothing & Advanced Textiles
				19,561
		> Electrical Components 0.8%
	280,000	Acuity Brands		15,618
		Commercial Lighting Fixtures
				15,618
		> Steel 0.5%
	486,000	GrafTech International (a)		9,851
		Industrial Graphite Materials Producer
				9,851

Number of Shares			Value (000)
		> Other Industrial Services 0.4%
	265,000	TrueBlue (a)	$	3,837
		Temporary Manual Labor
	109,000	Forward Air		3,683
		Freight Transportation Between Airports
				7,520
		> Industrial Distribution 0.4%
	350,000	Interline Brands (a)		6,430
		Industrial Distribution
				6,430
		> Waste Management 0.3%
	195,000	Waste Connections		6,187
		Solid Waste Management
				6,187
		> Water 0.1%
	204,200	Mueller Water Products		813
		Fire Hydrants, Valves & Ductile Iron Pipes
				813
Industrial Goods & Services: Total				288,094
Finance 9.9%
		> Banks 4.9%
	931,000	Valley National Bancorp		12,671
		New Jersey/New York Bank
	170,000	SVB Financial Group (a)		10,151
		Bank to Venture Capitalists
	692,400	Associated Banc-Corp		9,624
		Midwest Bank
	431,597	Lakeland Financial		9,607
		Indiana Bank
	480,000	MB Financial		9,235
		Chicago Bank
	659,800	TCF Financial		9,105
		Great Lakes Bank
	278,678	Hancock Holding		8,633
		Gulf Coast Bank
	1,478,200	First Busey		7,820
		Illinois Bank
	527,700	Pacific Continental		4,828
		Pacific Northwest Bank
	269,600	Eagle Bancorp (a)		3,586
		Metro D.C. Bank
	178,826	Sandy Spring Bancorp		3,217
		Baltimore/D.C. Bank
	210,000	CVB Financial		1,943
		Inland Empire Business Bank
	90,000	TriCo Bancshares		1,314
		California Central Valley Bank
	245,300	TrustCo Bank		1,202
		New York State Bank
	851,247	Guaranty Bancorp (a)		1,141
		Colorado Bank
				94,077
		> Finance Companies 3.3%
	345,000	World Acceptance (a)		22,622
		Personal Loans

See accompanying notes to financial statements.

53

Columbia Acorn USA

Statement of Investments (Unaudited), continued

Number of Shares			Value (000)
		> Finance Companies—continued
	412,500	Aaron's	$	11,657
		Rent to Own
	335,418	McGrath Rentcorp		9,418
		Temporary Space & IT Rentals
	285,000	Textainer Group Holdings		8,761
		Top International Container Leasor
	230,000	CAI International (a)		4,752
		International Container Leasing
	201,000	H&E Equipment Services (a)		2,812
		Heavy Equipment Leasing
	42,400	GATX		1,574
		Rail Car Lessor
	99,200	Marlin Business Services (a)		1,255
		Small Equipment Leasing
				62,851
		> Savings & Loans 0.9%
	756,000	ViewPoint Financial		10,433
		Texas Thrift
	215,000	Berkshire Hills Bancorp		4,814
		Northeast Thrift
	173,073	Kaiser Federal Financial Group		2,132
		Los Angeles Savings & Loan
				17,379
		> Brokerage & Money Management 0.6%
	209,500	Eaton Vance		6,333
		Specialty Mutual Funds
	675,000	MF Global (a)		5,225
		Futures Broker
				11,558
		> Insurance 0.2%
	39,000	Enstar Group (a)		4,075
		Insurance/Reinsurance & Related Services
				4,075
Finance: Total				189,940
Health Care 8.8%
		> Biotechnology & Drug Delivery 4.4%
	520,000	BioMarin Pharmaceutical (a)		14,149
		Biotech Focused on Orphan Diseases
	491,882	Seattle Genetics (a)		10,094
		Antibody-based Therapies for Cancer
	232,000	Onyx Pharmaceuticals (a)		8,190
		Commercial-stage Biotech Focused on Cancer
	840,000	NPS Pharmaceuticals (a)		7,938
		Orphan Drugs & Healthy Royalties
	850,000	Isis Pharmaceuticals (a)		7,786
		Biotech Pioneer in Anti-sense Drugs
	375,000	Auxilium Pharmaceuticals (a)		7,350
		Biotech Focused on Niche Disease Areas
	196,000	InterMune (a)		7,027
		Drugs for Pulmonary Fibrosis & Hepatitis C
	102,000	United Therapeutics (a)		5,620
		Biotech Focused on Rare Diseases
	810,000	Micromet (a)		4,649
		Next-generation Antibody Technology

Number of Shares			Value (000)
	790,000	Chelsea Therapeutics (a)	$	4,029
		Biotech Focused on Rare Diseases
	455,000	Nabi Biopharmaceuticals (a)		2,448
		Biotech Focused on Vaccines
	265,000	Anthera Pharmaceuticals (a)		2,165
		Biotech Focused on Cardiovascular, Cancer & Immunology
	243,000	Savient Pharmaceuticals (a)(b)		1,820
		Biotech Focused on Severe Gout
	450,000	Array Biopharma (a)		1,008
		Drugs for Cancer & Inflammatory Diseases
	18,181	Metabolex, Series A-1 (a)(d)		18
		Diabetes Drug Development
	738,060	Medicure - Warrants (a)(d)		—
		Cardiovascular Biotech Company
	37,500	Locus Pharmaceuticals, Series A-1, Pfd. (a)(d)		—
	19,329	Locus Pharmaceuticals, Series B-1, Pfd. (a)(d)		—
		High Throughput Rational Drug Design
				84,291
		> Medical Equipment & Devices 2.2%
	370,000	Alexion Pharmaceuticals (a)		17,401
		Biotech Focused on Orphan Diseases
	184,000	Sirona Dental Systems (a)		9,770
		Manufacturer of Dental Equipment
	124,000	Gen-Probe (a)		8,575
		Molecular In-vitro Diagnostics
	53,000	Idexx Laboratories (a)		4,111
		Diagnostic Equipment & Services for Veterinarians
	155,000	Pacific Biosciences of California (a)		1,813
		Genome Sequencing
				41,670
		> Medical Supplies 0.9%
	439,600	Cepheid (a)		15,228
		Molecular Diagnostics
	49,000	Neogen (a)		2,215
		Food & Animal Safety Products
				17,443
		> Health Care Services 0.8%
	1,038,900	Health Management Associates (a)		11,199
		Non-urban Hospitals
	151,000	Community Health Systems (a)		3,878
		Non-urban Hospitals
				15,077
		> Pharmaceuticals 0.3%
	725,000	Akorn (a)		5,075
		Develops, Manufactures & Sells Specialty Generic Drugs
	108,512	Alimera Sciences (a)		884
		Ophthalmogy-focused Pharmaceutical Company
				5,959
		> Hospital Management 0.2%
	150,000	Kindred Healthcare (a)		3,221
		Post-Acute Healthcare Facilities
				3,221
Health Care: Total				167,661

See accompanying notes to financial statements.

54

Number of Shares			Value (000)
Energy & Minerals 8.2%
		> Oil Services 4.4%
	1,000,000	FMC Technologies (a)	$	44,790
		Oil & Gas Wellhead Manufacturer
	803,000	Atwood Oceanics (a)		35,436
		Offshore Drilling Contractor
	86,000	Bristow		4,388
		Largest Provider of Helicopter Services to Offshore Oil & Gas Producers
				84,614
		> Oil & Gas Producers 2.9%
	1,135,000	Quicksilver Resources (a)		16,753
		Natural Gas & Coal Steam Gas Producer
	133,000	SM Energy		9,773
		Oil & Gas Producer
	143,000	Rosetta Resources (a)		7,370
		Oil & Gas Producer Exploring in South Texas & Montana
	386,000	Houston American Energy (b)		6,998
		Oil & Gas Exploration & Production in Colombia
	168,000	Swift Energy (a)		6,261
		Oil & Gas Exploration & Production Company
	230,000	Northern Oil & Gas (a)(b)		5,094
		Small E&P Company in North Dakota Bakken
	73,000	Carrizo Oil & Gas (a)		3,048
		Oil & Gas Producer
	22,800	Oasis Petroleum (a)		677
		Oil Producer in North Dakota
				55,974
		> Mining 0.9%
	100,000	Core Laboratories (Netherlands)		11,154
		Oil & Gas Reservoir Consulting
	600,000	Alexco Resource (a)		4,326
		Mining, Exploration & Environmental Services
	180,000	Augusta Resource (a)		834
		U.S. Copper/Molybdenum Mine
				16,314
Energy & Minerals: Total				156,902
Other Industries 6.4%
		> Real Estate 5.2%
	915,000	Extra Space Storage		19,517
		Self Storage Facilities
	995,200	BioMed Realty Trust		19,148
		Life Science-focused Office Buildings
	600,000	Associated Estates Realty		9,750
		Multi-family Properties
	246,000	Corporate Office Properties		7,653
		Office Buildings
	870,000	Education Realty Trust		7,456
		Student Housing
	177,000	Kilroy Realty		6,990
		West Coast Office & Industrial Properties
	1,380,000	Kite Realty Group		6,872
		Community Shopping Centers
	1,058,000	DCT Industrial Trust		5,533
		Industrial Properties

Number of Shares or Principal Amount			Value (000)
	98,619	Macerich	$	5,276
		Regional Shopping Malls
	191,000	Dupont Fabros Technology (b)		4,813
		Technology-focused Office Buildings
	100,000	Post Properties		4,076
		Multi-family Properties
	208,000	Summit Hotel Properties		2,361
		Owner of Select Service Hotels
				99,445
		> Transportation 1.2%
	410,091	Rush Enterprises, Class A (a)		7,804
	115,000	Rush Enterprises, Class B (a)		1,851
		Truck Sales & Services
	256,000	World Fuel Services		9,198
		Global Fuel Broker
	310,000	Heartland Express		5,134
		Regional Trucker
				23,987
Other Industries: Total				123,432
Total Equities: 99.4% (Cost: $1,231,445)				1,901,043
Securities Lending Collateral: 0.7%
	12,943,711	Dreyfus Government Cash Management Fund (e) (7 day yield of 0.00%)		12,944
Total Securities Lending Collateral: (Cost: $12,944)				12,944
Short-Term Obligation: 0.8%
		> Repurchase Agreement: 0.8%
$	15,821	Repurchase Agreement with Fixed Income Clearing Corp., dated 6/30/11, due 7/01/11 at 0.01%, collateralized by a U.S. Government Agency obligation maturing 8/18/17, market value $16,141 (repurchase proceeds $15,821)		15,821
Total Short Term Obligation: (Cost: $15,821)				15,821
Total Investments: 100.9% (Cost: $1,260,210) (f)				1,929,808
Obligation to Return Collateral for Securities Loaned: (0.7)%				(12,944	)
Cash and Other Assets Less Liabilities: (0.2)%				(4,519	)
Total Net Assets: 100.0%			$	1,912,345

  ADR = American Depositary Receipts.

See accompanying notes to financial statements.

55

Columbia Acorn USA

Statement of Investments (Unaudited), 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 June 30, 2011. The total market value of Fund securities on loan at June 30, 2011 was $12,520.

(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 this affiliated company during the six months ended June 30, 2011, are as follows:

Affiliate	Balance of Shares Held 12/31/10		Purchases/ Additions		Sales/ Reductions		Balance of Shares Held 6/30/11		Value		Dividend
RCM Technologies		710,000		-		-		710,000	$	3,798	$	-
Total of Affiliated Transactions		710,000		-		-		710,000	$	3,798	$	-

  The aggregate cost and value of this affiliated company at June 30, 2011, was $4,479 and $3,798. Investments in this affiliated company represented 0.2% of total net assets at June 30, 2011.

(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 June 30, 2011, the market value of these securities amounted to $18, 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 -1	2/11/00		18,181	$	2,000	$	18
Medicure - Warrants	12/22/06		738,060		-		-
Locus Pharmaceuticals, Series A-1 Pfd.	9/05/01		37,500		1,500		-
Locus Pharmaceuticals, Series B-1 Pfd.	2/08/07		19,329		56		-
				$	3,556	$	18

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

(f)  At June 30, 2011, for federal income tax purposes, the cost of investments was $1,260,210 and net unrealized appreciation was $669,598, consisting of gross unrealized appreciation of $760,468 and gross unrealized depreciation of $90,870.

  Various inputs are used in determining the value of the Fund's investments, following the input prioritization hierarchy established by GAAP. These inputs are summarized in the three broad levels listed below:

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

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

•  Level 3 – prices determined using significant unobservable inputs where quoted prices or observable inputs are unavailable or less reliable (including management's own assumptions about the factors market participants would use in pricing an investment)

  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 Fund 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 Valuation Committee of the Fund's Board of Trustees that rely on significant observable inputs are also included in level 2. Typical Level 3 securities include any security fair valued by the Valuation Committee that relies on significant unobservable inputs.

See accompanying notes to financial statements.

56

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

The following table summarizes the inputs used, as June 30, 2011, 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	$	651,445	$	-	$	-	$	651,445
Consumer Goods & Services		323,569		-		-		323,569
Industrial Goods & Services		288,094		-		-		288,094
Finance		189,940		-		-		189,940
Health Care		167,643		-		18		167,661
Energy & Minerals		156,902		-		-		156,902
Other Industries		123,432		-		-		123,432
Total Equities		1,901,025		-		18		1,901,043
Total Securities Lending Collateral		12,944		-		-		12,944
Total Short-Term Obligation		-		15,821		-		15,821
Total Investments	$	1,913,969	$	15,821	$	18	$	1,929,808

  The Fund's assets assigned to the Level 2 input category are generally valued using the market approach, in which a security's value is determined through its correlation to prices and information from market transactions for similar or identical assets. Warrants which do not trade are valued as a percentage of the actively trading common stock using a model, based on Black Scholes.

  Certain short-term obligations may be valued using amortized cost, an income approach which converts future cash flows to a present value based upon the discount or premium at purchase.

  The Fund's assets assigned to the Level 3 input category are valued at fair value as determined in good faith under consistently applied procedures established by and under the general supervision of the Board of Trustees. To determine fair value, management will utilize the valuation technique that they deem the most appropriate in the circumstances. Securities for which no market exists are valued based upon a market approach using some unobservable inputs which may include, but are not limited to, projected earnings, available cash, line of business, multiples, and consideration of the prioritization of the equity in a company's capital structure.

  There were no significant transfers of financial assets between levels 1 and 2 during the period.

  The following table reconciles asset balances for the six months ending June 30, 2011, in which significant unobservable inputs (Level 3) were used in determining value:

Investments in Securities	Balance as of December 31, 2010		Realized Gain/(Loss)		Change in Unrealized Appreciation (Depreciation)			Purchases		Sells		Transfers into Level 3		Transfers out of Level 3		Balance as of June 30, 2011
Equities
Health Care	$	20	$	-	$	(2	)	$	-	$	-	$	-	$	-	$	18
	$	20	$	-	$	(2	)	$	-	$	-	$	-	$	-	$	18

  The information in the above reconciliation represents fiscal year to date activity for any securities identified as using Level 3 inputs at either the beginning or the end of the current fiscal period.

  The change in unrealized depreciation attributed to securities owned at June 30, 2011, which were valued using significant unobservable inputs (Level 3) amounted to $2. This amount is included in net change in unrealized appreciation (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.

57

Columbia Acorn International Select

Major Portfolio Changes in the Second Quarter (Unaudited)

	Number of Shares
	03/31/11		06/30/11
Purchases
Europe
> United Kingdom
Archipelago Resources		2,775,000		4,472,797
Chemring		1,465,000		1,609,133
JLT Group		517,000		881,100
> Netherlands
Imtech		231,504		235,519
> Germany
Rhoen-Klinikum		200,000		297,000
> Switzerland
Partners Group		0		24,000
> Belgium
EVS Broadcast Equipment		0		33,800
Asia
> Singapore
Ascendas REIT		11,105,000		13,130,000
Mapletree Industrial Trust REIT		0		14,601,100
> China
Want Want		0		1,655,000
Zhaojin Mining Industry		1,324,700		2,649,400
Other Countries
> South Africa
Rand Merchant Insurance		0		4,902,152

	Number of Shares
	03/31/11		06/30/11
Sales
Europe
> United Kingdom
Cobham		2,415,000		616,000
Intertek Group		412,000		400,000
Petropavlovsk		568,000		0
Serco		2,139,000		985,000
Workspace Group		13,437,411		9,710,000
> Netherlands
Fugro		175,427		117,121
> Sweeden
Hexagon		774,666		658,666
> Switzerland
Bank Sarasin & Cie		99,000		0
> Ireland
United Drug		3,213,000		2,377,800
> France
Neopost		130,000		48,000
> Spain
Red Eléctrica de España		80,000		0
Asia
> Japan
Benesse		15,400		0
Gree		521,000		280,000
> China
Jiangsu Expressway		12,115,400		6,727,000
> Hong Kong
Hutchison Port Holdings Trust		1,515,000		0
Other Countries
> Canada
Pan American Silver		132,000		0
> United States
Atwood Oceanics		143,000		112,000
> Austriala
UGL		571,848		540,000
Latin America
> Columbia
Pacific Rubiales Energy		525,000		260,000

See accompanying notes to financial statements.

58

Columbia Acorn International Select

Statement of Investments (Unaudited), June 30, 2011

Number of Shares			Value (000)
			Equities: 87.0%
Europe 41.3%
		> United Kingdom 13.9%
	1,609,133	Chemring	$	16,529
		Defense Manufacturer of Countermeasures & Energetics
	400,000	Intertek Group		12,666
		Testing, Inspection & Certification Services
	881,100	JLT Group		9,630
		International Business Insurance Broker
	985,000	Serco		8,734
		Facilities Management
	9,710,000	Workspace Group		4,714
		United Kingdom Real Estate
	4,472,797	Archipelago Resources (a)		4,433
		Gold Mining Projects in Indonesia, Vietnam & the Philippines
	616,000	Cobham		2,092
		Aerospace Components
	226,800	Shaftesbury		1,922
		London Prime Retail REIT
				60,720
		> Netherlands 8.7%
	166,000	AkzoNobel		10,472
		Largest Global Supplier of Protective Paints & Coatings
	117,121	Fugro		8,445
		Sub-sea Oilfield Services
	235,519	Imtech		8,330
		Electromechanical & Information & Communications Technologies Installation & Maintenance
	242,103	Aalberts Industries		5,659
		Flow Control & Heat Treatment
	45,000	Core Laboratories		5,019
		Oil & Gas Reservoir Consulting
				37,925
		> Germany 6.7%
	672,000	Wirecard		12,011
		Online Payment Processing & Risk Management
	115,500	Rheinmetall		10,225
		Defense & Automotive
	297,000	Rhoen-Klinikum		7,167
		Health Care Services
				29,403
		> Sweden 3.7%
	658,666	Hexagon		16,224
		Measurement Equipment & Software
				16,224
		> Switzerland 2.7%
	51,000	Kuehne & Nagel		7,740
		Freight Forwarding/Logistics
	24,000	Partners Group		4,248
		Private Markets Asset Management
				11,988

Number of Shares			Value (000)
		> Ireland 1.9%
	2,377,800	United Drug	$	8,145
		Irish Pharmaceutical Wholesaler & Outsourcer
				8,145
		> Iceland 1.2%
	4,800,000	Marel (a)		5,081
		Largest Manufacturer of Poultry & Fish Processing Equipment
				5,081
		> Denmark 1.1%
	29,000	Novozymes		4,719
		Industrial Enzymes
				4,719
		> France 0.9%
	48,000	Neopost		4,123
		Postage Meter Machines
				4,123
		> Belgium 0.5%
	33,800	EVS Broadcast Equipment		2,288
		Digital Live Mobile Production Software & Systems
				2,288
Europe: Total				180,616
Asia 29.1%
		> Japan 13.5%
	2,115,000	Kansai Paint		19,270
		Paint Producer in Japan, India, China & Southeast Asia
	480,000	Asahi Diamond Industrial		10,494
		Consumable Diamond Tools
	8,550	Jupiter Telecommunications		9,566
		Largest Cable Service Provider in Japan
	4,450	Seven Bank		8,892
		ATM Processing Services
	280,000	Gree (a)		6,121
		Mobile Social Networking Game Developer/Platform
	110,000	Ain Pharmaciez		4,526
		Dispensing Pharmacy/Drugstore Operator
				58,869
		> Singapore 8.2%
	13,130,000	Ascendas REIT		21,838
		Industrial Property Landlord
	14,601,100	Mapletree Industrial Trust REIT		13,923
		Industrial Property Landlord
				35,761
		> South Korea 4.4%
	79,266	NHN (a)		14,053
		South Korea's Largest Online Search Engine
	151,000	Woongjin Coway		5,385
		South Korean Household Appliance Rental Service Provider
				19,438

See accompanying notes to financial statements.

59

Columbia Acorn International Select

Statement of Investments (Unaudited), continued

Number of Shares			Value (000)
		> China 3.0%
	6,727,000	Jiangsu Expressway	$	6,167
		Chinese Toll Road Operator
	2,649,400	Zhaojin Mining Industry		5,466
		Gold Mining & Refining in China
	1,655,000	Want Want		1,607
		Chinese Branded Consumer Food Company
				13,240
Asia: Total				127,308
Other Countries 14.2%
		> South Africa 6.0%
	1,152,200	Adcock Ingram Holdings		10,123
		Manufacturer of Pharmaceuticals & Medical Supplies
	4,902,152	Rand Merchant Insurance		8,954
		Directly Sold Property & Casualty Insurance; Holdings in Other Insurers
	122,700	Naspers		6,931
		Media in Africa, China, Russia & Other Emerging Markets
				26,008
		> Canada 3.0%
	210,400	CCL Industries		7,234
		Leading Global Label Manufacturer
	125,000	AG Growth		5,936
		Leading Manufacturer of Augers & Grain Handling Equipment
				13,170
		> United States 2.3%
	112,000	Atwood Oceanics (a)		4,943
		Offshore Drilling Contractor
	67,000	SM Energy		4,923
		Oil & Gas Producer
				9,866
		> Australia 1.8%
	540,000	UGL		8,070
		Engineering & Facilities Management
				8,070
		> Israel 1.1%
	310,000	Israel Chemicals		4,947
		Producer of Potash, Phosphates, Bromine & Specialty Chemicals
				4,947
Other Countries: Total				62,061
Latin America 2.4%
		> Colombia 1.9%
	260,000	Pacific Rubiales Energy		6,969
		Oil Production & Exploration in Colombia
	18,800,000	Quetzal Energy (a)(b)		1,497
		Explores for Oil & Gas in Latin America
				8,466

Number of Shares or Principal Amount (000)			Value (000)
		> Argentina 0.5%
	1,000,000	Union Agriculture Group (a)(b)	$	2,200
		Farmland Operator in Uruguay
				2,200
Latin America: Total				10,666
Total Equities: 87.0% (Cost: $282,220)				380,651
Short-Term Obligation: 13.5%
		> Repurchase Agreement 13.5%
$	58,891	Repurchase Agreement with Fixed Income Clearing Corp., dated 6/30/11, due 7/01/11 at 0.01%, collateralized by a U.S. Government Agency obligation maturing 9/08/17, market value $60,070 (repurchase proceeds $58,891)		58,891
Total Short-Term Obligation 13.5% (Cost: $58,891)				58,891
Total Investments: 100.5% (Cost: $341,111)(c)(d)				439,542
Cash and Other Assets Less Liabilities: (0.5)%				(2,243	)
Total Net Assets: 100%			$	437,299

See accompanying notes to financial statements.

60

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

(a)  Non-income producing security.

(b)  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 June 30, 2011, the market value of these securities amounted to $3,697, which represented 0.85% of total net assets.

  Additional information on these securities is as follows:

Security	Acquisition Dates	Shares		Cost		Value
Union Agriculture Group	12/8/10		1,000,000	$	2,200	$	2,200
Quetzal Energy	1/14/11		18,800,000		2,376		1,497
				$	4,576	$	3,697

(c)  At June 30, 2011, for federal income tax purposes, the cost of investments was $341,111 and net unrealized appreciation was $98,431, consisting of gross unrealized appreciation of $103,528 and gross unrealized depreciation of $5,097.

(d)  On June 30, 2011, the Fund's total investments were denominated in currencies as follows:

Currency	Value		Percentage of Net Assets
Euro	$	76,865		17.6
U.S. Dollar		75,976		17.4
British Pound		60,720		13.9
Japanese Yen		58,869		13.5
Singapore Dollar		35,761		8.2
South African Rand		26,008		5.9
Other currencies less than 5% of total net assets		105,343		24.0
	$	439,542		100.5

  Various inputs are used in determining the value of the Fund's investments, following the input prioritization hierarchy established by GAAP. These inputs are summarized in the three broad levels listed below:

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

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

•  Level 3 – prices determined using significant unobservable inputs where quoted prices or observable inputs are unavailable or less reliable (including management's own assumptions about the factors market participants would use in pricing an investment)

  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 Fund 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 Valuation Committee of the Fund's Board of Trustees that rely on significant observable inputs are also included in level 2. Typical Level 3 securities include any security fair valued by the Valuation Committee that relies on significant unobservable inputs.

The following table summarizes the inputs used, as June 30, 2011, 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	$	5,019	$	175,597	$	-	$	180,616
Asia		-		127,308		-		127,308
Other Countries		23,036		39,025		-		62,061
Latin America		6,969		1,497		2,200		10,666
Total Equities		35,024		343,427		2,200		380,651
Total Short-Term Obligation		-		58,891		-		58,891
Total Investments	$	35,024	$	402,318	$	2,200	$	439,542

See accompanying notes to financial statements.

61

Columbia Acorn International Select

Statement of Investments (Unaudited), continued

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

  The Fund's assets assigned to the Level 2 input category are generally valued using the market approach, in which a security's value is determined through its correlation to prices and information from market transactions for similar or identical assets. Foreign equities are generally valued at the last sales price on the foreign exchange or market on which they trade. The Fund may use a systematic fair valuation model provided by an independent third party to value securities principally traded in foreign markets in order to adjust for possible stale pricing that may occur between the close of the foreign exchanges and the time for valuation. These models take into account available market data including intraday index, ADR, and ETF movements. Securities acquired via private placement that have a holding period or an extended settlement period are valued at a discount to the same shares that are trading freely on the market. These discounts are determined by the adviser's experience with similar securities or situations. Factors may include, but are not limited to, trade volume, shares outstanding and stock price.

  Certain short-term obligations may be valued using amortized cost, an income approach which converts future cash flows to a present value based upon the discount or premium at purchase.

  The Fund's assets assigned to the Level 3 input category are valued at fair value as determined in good faith under consistently applied procedures established by and under the general supervision of the Board of Trustees. To determine fair value, management will utilize the valuation technique that they deem the most appropriate in the circumstances. Securities acquired via private placement that are not yet trading are valued using a market approach for which management has determined that the original transaction price is the best representation of fair value. The original cost may be adjusted for the market movement in an index, ETF or similar security during the period it does not trade. Securities for which no market exists are valued based upon a market approach using some unobservable inputs which may include, but are not limited to, projected earnings, available cash, line of business, multiples and consideration of the prioritization of the equity in the company's capital structure.

  There were no significant transfers of financial assets between Levels 1 and 2 during the period.

  The following table reconciles asset balances for the six months ending June 30, 2011, in which significant unobservable inputs (Level 3) were used in determining value:

Investments in Securities	Balance as of December 31, 2010		Realized Gain/(Loss)		Change in Unrealized Appreciation (Depreciation)		Purchases		Sales		Transfers into Level 3		Transfers out of Level 3		Balance as of June 30, 2011
Latin America
Argentina	$	2,200	$	-	$	-	$	-	$	-	$	-	$	-	$	2,200
	$	2,200	$	-	$	-	$	-	$	-	$	-	$	-	$	2,200

  The information in the above reconciliation table represents fiscal year to date activity for any securities identified as using Level 3 inputs at either the beginning or the end of the current fiscal period.

  The change in unrealized appreciation (depreciation) attributed to securities owned at June 30, 2011, which were valued using significant unobservable inputs (Level 3) amounted to $0. This amount is included in net change unrealized appreciation (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 Acorn International Select

Portfolio Diversification (Unaudited)

At June 30, 2011, the Fund's portfolio investments as a percentage of net assets were diversified as follows:

	Value (000)		Percentage of Net Assets
> Industrial Goods & Services
Industrial Materials & Specialty Chemicals	$	39,408		9.0
Other Industrial Services		36,806		8.4
Machinery		35,859		8.2
Electrical Components		18,621		4.3
Outsourcing Services		8,734		2.0
Conglomerates		5,659		1.3
		145,087		33.2
> Information
Internet Related		20,984		4.8
Instrumentation		16,224		3.7
Financial Processors		12,011		2.7
CATV		9,566		2.2
Gaming Equipment & Services		6,121		1.4
Business Software		2,288		0.5
		67,194		15.3
> Other Industries
Real Estate		42,397		9.7
Transportation		6,167		1.4
		48,564		11.1
> Energy & Minerals
Mining		14,918		3.4
Oil & Gas Producers		13,389		3.1
Oil Services		13,388		3.1
Agricultural Commodities		2,200		0.5
		43,895		10.1
> Finance
Insurance		18,584		4.2
Banks		8,892		2.0
Brokerage & Money Management		4,248		1.0
		31,724		7.2
> Health Care
Pharmaceuticals		18,268		4.2
Health Care Services		7,167		1.6
		25,435		5.8

	Value (000)			Percentage of Net Assets
> Consumer Goods & Services
Nondurables		7,234			1.7
Other Consumer Services		5,385			1.2
Retail		4,526			1.0
Food & Beverage		1,607			0.4
		18,752			4.3
Total Equities:		380,651			87.0
Short-Term Obligation:		58,891			13.5
Total Investments:		439,542			100.5
Cash and Other Assets Less Liabilities:		(2,243	)		(0.5	)
Net Assets:	$	437,299			100.0

See accompanying notes to financial statements.

63

Columbia Acorn Select

Major Portfolio Changes in the Second Quarter (Unaudited)

	Number of Shares
	03/31/11		06/30/11
Purchases
Consumer Goods & Services
Gaylord Entertainment		0		860,000
Industrial Goods & Services
Quanta Services		0		1,400,000
Information
Finisar		0		324,000
SBA Communications		505,000		755,000
WNS - ADR (India)		4,200,000		4,227,186
Energy & Minerals
Canadian Solar (China)		3,200,000		3,300,000
Health Care
Akorn		1,996,847		2,250,000

	Number of Shares
	03/31/11		06/30/11
Sales
Consumer Goods & Services
Abercrombie & Fitch		1,600,000		1,100,000
Career Education		1,900,000		0
Coach		1,135,000		1,025,000
Hertz		8,650,000		8,400,000
ITT Educational Services		1,000,000		325,000
Safeway		3,600,000		3,000,000
Thor Industries		720,000		0
Industrial Goods & Services
Ametek		1,860,000		1,830,000
ChemSpec International - ADR (China)		1,581,700		1,500,000
Donaldson		800,000		785,000
Nalco Holding Company		1,000,000		0
Pall		860,000		840,000
Waste Management		1,500,000		1,200,000
Information
American Tower		900,000		0
Crown Castle International		1,550,000		1,510,000
Navigant Consulting		2,300,000		813,073
Sanmina-SCI		7,100,000		6,950,000
VisionChina Media - ADR (China)		3,675,000		3,573,400
Energy & Minerals
Pacific Rubiales Energy (Colombia)		3,700,000		2,500,000
Synthesis Energy Systems (China)		4,426,330		3,850,372
Finance
CNO Financial Group		12,500,000		12,300,000
Discover Financial Services		5,150,000		5,050,000
MF Global		6,000,000		5,550,000
Other Industries
JB Hunt Transport Services		1,300,000		1,275,000

See accompanying notes to financial statements.

64

Columbia Acorn Select

Statement of Investments (Unaudited), June 30, 2011

Number of Shares			Value (000)
			Equities: 95.1%
Consumer Goods & Services 24.2%
		> Retail 9.9%
	1,100,000	Abercrombie & Fitch	$	73,612
		Teen Apparel Retailer
	3,000,000	Safeway		70,110
		Supermarkets
	350,000	lululemon athletica (a)(b)		39,137
		Premium Active Apparel Retailer
	250,000	Tiffany & Co.		19,630
		Luxury Good Retailer
				202,489
		> Travel 7.8%
	8,400,000	Hertz (a)		133,392
		Largest U.S. Rental Car Operator
	860,000	Gaylord Entertainment (a)		25,800
		Convention Hotels
				159,192
		> Apparel 3.2%
	1,025,000	Coach		65,528
		Designer & Retailer of Branded Leather Accessories
				65,528
		> Casinos & Gaming 1.6%
	335,000,000	RexLot Holdings (China)		32,405
		Lottery Equipment Supplier in China
				32,405
		> Educational Services 1.2%
	325,000	ITT Educational Services (a)(b)		25,428
		Post-secondary Degree Services
				25,428
		> Food & Beverage 0.3%
	1,000,000	GLG Life Tech (Canada) (a)		6,720
		Produce an All-natural Sweetener Extracted from the Stevia Plant
				6,720
		> Other Consumer Services 0.2%
	2,300,000	IFM Investments (Century 21 China RE) - ADR (China) (a)(c)		3,381
		Provides Real Estate Services in China
				3,381
Consumer Goods & Services: Total				495,143
Industrial Goods & Services 19.0%
		> Machinery 11.4%
	1,830,000	Ametek		82,167
		Aerospace/Industrial Instruments
	785,000	Donaldson		47,634
		Industrial Air Filtration
	840,000	Pall		47,233
		Filtration & Fluids Clarification
	885,000	Kennametal		37,356
		Consumable Cutting Tools
	650,000	Oshkosh (a)		18,811
		Specialty Truck Manufacturer
				233,201

Number of Shares			Value (000)
		> Waste Management 2.2%
	1,200,000	Waste Management	$	44,724
		U.S. Garbage Collection & Disposal
				44,724
		> Other Industrial Services 1.9%
	750,000	Expeditors International of Washington		38,392
		International Freight Forwarder
				38,392
		> Industrial Distribution 1.6%
	220,000	WW Grainger		33,803
		Industrial Distribution
				33,803
		> Outsourcing Services 1.4%
	1,400,000	Quanta Services (a)		28,280
		Electrical & Telecom Construction Services
				28,280
		> Industrial Materials & Specialty Chemicals 0.5%
	1,500,000	ChemSpec International - ADR (China) (a)		10,800
		Specialty Chemicals with Focus on Fluorinated Chemical Manufacturing
				10,800
Industrial Goods & Services: Total				389,200
Information 15.3%
		> Mobile Communications 5.3%
	1,510,000	Crown Castle International (a)		61,593
		Communications Towers
	755,000	SBA Communications (a)		28,833
		Communications Towers
	15,000,000	Globalstar (a)(b)(c)		18,450
		Satellite Mobile Voice & Data Carrier
				108,876
		> Contract Manufacturing 3.5%
	6,950,000	Sanmina-SCI (a)(c)		71,793
		Electronic Manufacturing Services
				71,793
		> Computer Hardware & Related Equipment 2.0%
	750,000	Amphenol		40,493
		Electronic Connectors
				40,493
		> Computer Services 1.8%
	4,227,186	WNS - ADR (India) (a)(c)		37,580
		Offshore BPO (Business Process Outsourcing) Services
				37,580
		> Instrumentation 1.0%
	120,000	Mettler Toledo (a)		20,240
		Laboratory Equipment
				20,240

See accompanying notes to financial statements.

65

Columbia Acorn Select

Statement of Investments (Unaudited), continued

Number of Shares			Value (000)
		> Advertising 0.5%
	3,573,400	VisionChina Media - ADR (China) (a)(b)	$	10,113
		Advertising on Digital Screens in China's Mass Transit System
				10,113
		> Business Software 0.5%
	182,000	Concur Technologies (a)		9,113
		Web Enabled Cost & Expense Management Software
				9,113
		> Business Information & Marketing Services 0.4%
	813,073	Navigant Consulting (a)		8,529
		Financial Consulting Firm
				8,529
		> Telecommunications Equipment 0.3%
	324,000	Finisar (a)		5,842
		Optical Sub-systems & Components
				5,842
Information: Total				312,579
Energy & Minerals 14.7%
		> Oil & Gas Producers 9.4%
	2,500,000	Pacific Rubiales Energy (Colombia)		67,007
		Oil Production & Exploration in Colombia
	30,530,000	Canacol Energy (Colombia) (a)(c)		33,555
	4,000,000	Canacol Energy (Colombia) (a)(c)(d)		4,308
		Oil Producer in South America
	38,343,900	ShaMaran Petroleum (Iraq) (a)(c)		30,216
		Oil Exploration in Kurdistan
	1,450,000	Houston American Energy (b)		26,288
		Oil & Gas Exploration & Production in Colombia
	34,856,000	Petrodorado (Colombia) (a)(c)		11,023
	17,144,000	Petrodorado - Warrants (Colombia) (a)(c)(d)		1,740
		Oil & Gas Exploration & Production in Colombia, Peru & Paraguay
	24,000,000	Canadian Overseas Petroleum (United Kingdom) (a)(c)(d)		11,096
	12,000,000	Canadian Overseas Petroleum - Warrants (United Kingdom) (a)(c)(d)		1,635
		Oil & Gas Exploration/Production in the North Sea
	13,125,000	Petromanas (Canada) (a)(d)		3,868
	5,000,000	Petromanas (Canada) (a)		1,503
	6,562,500	Petromanas - Warrants (Canada) (a)(d)		167
		Exploring for Oil in Albania
				192,406
		> Alternative Energy 2.4%
	3,300,000	Canadian Solar (China) (a)(b)(c)		37,950
		Solar Cell & Module Manufacturer
	3,850,372	Synthesis Energy Systems (China) (a)(b)(c)		7,200
		Owner/Operator of Gasification Plants
	1,600,000	Real Goods Solar (a)(c)		4,736
		Residential Solar Energy Installer
				49,886

Number of Shares			Value (000)
		> Agricultural Commodities 1.6%
	9,090,909	Union Agriculture Group (Argentina) (a)(d)	$	20,000
		Farmland Operator in Uruguay
	38,000,000	Eacom Timber (Canada) (a)(c)(d)		11,970
		Canadian Lumber Producer
				31,970
		> Mining 0.8%
	1,000,000	Kirkland Lake Gold (Canada) (a)		15,760
		Gold Mining
				15,760
		> Oil Services 0.5%
	10,885,700	Tuscany International Drilling (Colombia) (a)		10,384
	760,000	Tuscany International Drilling - Warrants (Colombia) (a)		28
		South America-based Drilling Rig Contractor
				10,412
Energy & Minerals: Total				300,434
Finance 14.7%
		> Credit Cards 6.6%
	5,050,000	Discover Financial Services		135,088
		Credit Card Company
				135,088
		> Insurance 4.8%
	12,300,000	CNO Financial Group (a)		97,293
		Life, Long-term Care & Medical Supplement Insurance
				97,293
		> Brokerage & Money Management 3.3%
	5,550,000	MF Global (a)		42,957
		Futures Broker
	1,100,000	SEI Investments		24,761
		Mutual Fund Administration & Investment Management
				67,718
Finance: Total				300,099
Other Industries 5.5%
		> Transportation 2.9%
	1,275,000	JB Hunt Transport Services		60,040
		Truck & Intermodal Carrier
				60,040
		> Real Estate 1.8%
	1,900,000	BioMed Realty Trust		36,556
		Life Science-focused Office Buildings
				36,556
		> Regulated Utilities 0.8%
	500,000	Wisconsin Energy		15,675
		Wisconsin Utility
				15,675
Other Industries: Total				112,271

See accompanying notes to financial statements.

66

Number of Shares or Principal Amount (000)			Value (000)
Health Care 1.7%
		> Biotechnology & Drug Delivery 0.9%
	2,000,000	NPS Pharmaceuticals (a)	$	18,900
		Orphan Drugs & Healthy Royalties
				18,900
		> Pharmaceuticals 0.8%
	2,250,000	Akorn (a)		15,750
		Develops, Manufactures & Sells Specialty Generic Drugs
				15,750
Health Care: Total				34,650
Total Equities: 95.1% (Cost: $1,465,678)				1,944,376
Securities Lending Collateral: 3.0%
	61,633,705	Dreyfus Government Cash Management Fund (e) (7 day yield of 0.00%)		61,634
Total Securities Lending Collateral: (Cost: $61,634)				61,634
Short-Term Obligation 4.6%
		> Repurchase Agreement 4.6%
$	94,733	Repurchase Agreement with Fixed Income Clearing Corp., dated 6/30/11, due 7/01/11 at 0.01%, collateralized by a U.S. Government Agency obligation maturing 8/18/17, market value $96,628 (repurchase proceeds $94,733)		94,733
				94,733
Total Short-Term Obligation: (Cost: $94,733)				94,733
Total Investments: 102.7% (Cost: $1,622,045)(f)				2,100,743
Obligation to Return Collateral for Securities Loaned: (3.0)%				(61,634	)
Cash and Other Assets Less Liabilities: 0.3%				5,958
Total Net Assets: 100.0%			$	2,045,067

ADR = American Depositary Receipts

See accompanying notes to financial statements.

67

Columbia Acorn Select

Statement of Investments (Unaudited), 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 June 30, 2011. The total market value of Fund securities on loan at June 30, 2011 was $59,666.

(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 six months ended June 30, 2011, are as follows:

Affiliates	Balance of Shares Held 12/31/10		Purchases/ Additions		Sales/ Reductions		Balance of Shares Held 6/30/11		Value		Dividend
Canacol Energy		36,240,000		-		1,710,000		34,530,000	$	37,863	$	-
Canadian Overseas Petroleum+		16,800,000		36,000,000		16,800,000		36,000,000		12,731		-
Canadian Solar		3,200,000		100,000		-		3,300,000		37,950		-
Eacom Timber		38,000,000		-		-		38,000,000		11,970		-
Globalstar		15,000,000		-		-		15,000,000		18,450		-
IFM Investments (Century 21 China RE) - ADR		2,300,000		-		-		2,300,000		3,381		-
Petrodorado+		45,544,000		6,456,000		-		52,000,000		12,763		-
Real Goods Solar		1,500,000		100,000		-		1,600,000		4,736		-
Sanmina-SCI		7,100,000		-		150,000		6,950,000		71,793		-
ShaMaran Petroleum		35,950,000		2,843,100		449,200		38,343,900		30,216		-
Synthesis Energy Systems		4,500,000		-		649,628		3,850,372		7,200		-
Tuscany International Drilling*+		13,224,000		-		1,578,300		11,645,700		10,412		-
VisionChina Media - ADR*		3,675,000		-		101,600		3,573,400		10,113		-
WNS - ADR		4,200,000		27,186		-		4,227,186		37,580		-
Total of Affiliated Transactions		227,233,000		45,526,286		21,438,728		251,320,558	$	307,158	$	-

*  At June 30, 2011, the Fund owned less than five percent of the company's outstanding voting shares.

+  Includes the effects of a corporate action.

  The aggregate cost and value of these affiliated companies at June 30, 2011, were $368,957 and $286,633, respectively. Investments in affiliated companies represented 14.0% of the Fund's total net assets at June 30, 2011.

(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 June 30, 2011, the value of these securities amounted to $54,784, which represented 2.68% of total net assets.

  Additional information on these securities is as follows:

Security	Acquisition Dates	Shares		Cost		Value
Union Agriculture Group	12/08/10		9,090,909	$	20,000	$	20,000
Eacom Timber	3/17/10		38,000,000		18,812		11,970
Canadian Overseas Petroleum	11/24/10		24,000,000		10,260		11,096
Canacol Energy	4/15/10		4,000,000		2,963		4,308
Petromanas	5/20/10		13,125,000		4,561		3,868
Petrodorado - Warrants	11/20/09		17,144,000		2,118		1,740
Canadian Overseas Petroleum - Warrants	11/24/10		12,000,000		1,502		1,635
Petromanas - Warrants	5/20/10		6,562,500		380		167
				$	60,596	$	54,784

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

(f)  At June 30, 2011, for federal income tax purposes, the cost of investments was $1,622,045 and net unrealized appreciation was $478,698, consisting of gross unrealized appreciation of $688,871 and gross unrealized depreciation of $210,173.

  Various inputs are used in determining the value of the Fund's investments, following the input prioritization hierarchy established by GAAP. These inputs are summarized in the three broad levels listed below:

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

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

•  Level 3 – prices determined using significant unobservable inputs where quoted prices or observable inputs are unavailable or less reliable (including management's own assumptions about the factors market participants would use in pricing an investment)

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

See accompanying notes to financial statements.

68

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

  Examples of the types of securities in which the Fund 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 Valuation Committee of the Fund's Board of Trustees that rely on significant observable inputs are also included in Level 2. Typical Level 3 securities include any security fair valued by the Valuation Committee that relies on significant unobservable inputs.

The following table summarizes the inputs used, as of June 30, 2011, 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	$	462,738	$	32,405	$	—	$	495,143
Industrial Goods & Services		389,200		—		—		389,200
Information		312,579		—		—		312,579
Energy & Minerals		245,650		34,784		20,000		300,434
Finance		300,099		—		—		300,099
Other Industries		112,271		—		—		112,271
Health Care		34,650		—		—		34,650
Total Equities		1,857,187		67,189		20,000		1,944,376
Total Securities Lending Collateral		61,634		—		—		61,634
Total Short-Term Obligation		—		94,733		—		94,733
Total Investments	$	1,918,821	$	161,922	$	20,000	$	2,100,743

  The Fund's assets assigned to the Level 2 input category are generally valued using a market approach, in which a security's value is determined through its correlation to prices and information from observable market transactions for similar or identical assets. Foreign equities are generally valued at the last sales price on the foreign exchange or market on which they trade. The Fund may use a systematic fair valuation model provided by an independent third party to value securities principally traded in foreign markets in order to adjust for possible stale pricing that may occur between the close of the foreign exchanges and the time for valuation. These models take into account available market data including intraday index, ADR, and ETF movements. Securities acquired via private placement that have a holding period or an extended settlement period are valued at a discount to the same shares that are trading freely on the market. These discounts are determined by the adviser's experience with similar securities or situations. Factors may include, but are not limited to, trade volume, shares outstanding and stock price. Warrants which do not trade are valued as a percentage of the actively trading common stocks using a model based on Black Scholes.

  Certain short-term obligations may be valued using amortized cost, an income approach which converts future cash flows to a present value based upon the discount or premium at purchase.

  The Fund's assets assigned to the Level 3 input category are valued at fair value as determined in good faith under consistently applied procedures established by and under the general supervision of the Board of Trustees. To determine fair value, management will utilize the valuation technique that they deem the most appropriate in the circumstances. Securities acquired via private placement that are not yet trading are valued using a market approach for which management has determined that the original transaction price is the best representation of fair value. The original cost may be adjusted for the market movement in an index, ETF or similar security during the period it does not trade.

  There were no significant transfers of financial assets between levels 1 and 2 during the period.

  The following table reconciles asset balances for the six months ending June 30, 2011, in which significant unobservable inputs (Level 3) were used in determining value:

Investments in Securities	Balance as of December 31, 2010		Realized Gain/(Loss)		Change in Unrealized Appreciation (Depreciation)		Purchases		Sales		Transfers into Level 3		Transfers out of Level 3		Balance as of June 30, 2011
Equities
Energy & Minerals	$	20,000	$	-	$	-	$	-	$	-	$	-	$	-	$	20,000
	$	20,000	$	-	$	-	$	-	$	-	$	-	$	-	$	20,000

  The information in the above reconciliation table represents fiscal year to date activity for any securities identified as using Level 3 inputs at either the beginning or the end of the current fiscal period.

  The change in unrealized appreciation (depreciation) attributed to securities owned at June 30, 2011, which were valued using significant unobservable inputs (Level 3) amounted to $0. This amount is included in net change in unrealized appreciation (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.

69

Columbia Thermostat Fund

Statement of Investments (Unaudited), June 30, 2011

Number of Shares			Value (000)
		> Affiliated Stock Funds: 60.6%
	1,221	Columbia Dividend Income Fund, Class I	$	16,734
	394	Columbia Acorn International, Class I		16,221
	577	Columbia Marsico Growth Fund, Class I		12,678
	396	Columbia Acorn Fund, Class I		12,664
	301	Columbia Acorn Select, Class I		8,493
	652	Columbia Large Cap Enhanced Core Fund, Class I		8,439
	555	Columbia Contrarian Core Fund, Class I		8,392
Total Stock Funds: (Cost: $65,310)				83,621
		> Affiliated Bond Funds: 39.2%
	2,969	Columbia Intermediate Bond Fund, Class I		27,015
	1,450	Columbia U.S. Treasury Index Fund, Class I		16,237
	1,120	Columbia Income Opportunities Fund, Class I		10,804
Total Bond Funds: (Cost: $53,022)				54,056

Principal Amount (000)			Value (000)
Short-Term Obligation: 0.4%
		> Repurchase Agreement: 0.4%
$	478	Repurchase Agreement with Fixed Income Clearing Corp., dated 6/30/11, due 7/01/11 at 0.01%, collateralized by a U.S. Government Agency obligation maturing 8/18/17, market value $490 (repurchase proceeds $478)	$	478
Total Short-Term Obligation: (Cost: $478)				478
Total Investments: 100.2% (Cost: $118,810)(a)				138,155
Cash and Other Assets Less Liabilities: (0.2)%				(216	)
Total Net Assets: 100.0%			$	137,939

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

(a)  At June 30, 2011, for federal income tax purposes, the cost of investments was $118,810 and net unrealized appreciation was $19,345, consisting of gross unrealized appreciation of $19,646 and gross unrealized depreciation of $301.

  Various inputs are used in determining the value of the Fund's investments, following the input prioritization hierarchy established by GAAP. These inputs are summarized in the three broad levels listed below:

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

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

•  Level 3 – prices determined using significant unobservable inputs where quoted prices or observable inputs are unavailable or less reliable (including management's own assumptions about the factors market participants would use in pricing an investment)

  The inputs or methodology 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 Fund 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 Valuation Committee of the Fund's Board of Trustees that rely on significant observable inputs are also included in Level 2. Typical Level 3 securities include any security fair valued by the Valuation Committee that relies on significant unobservable inputs.

The following table summarizes the inputs used, as of June 30, 2011, 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	$	83,621	$	-	$	-	$	83,621
Total Bond Funds		54,056		-		-		54,056
Total Short-Term Obligation		-		478		-		478
Total Investments	$	137,677	$	478	$	-	$	138,155

  The Fund's assets assigned to the Level 2 category include certain short-term obligations generally valued using amortized cost, an income approach which converts future cash flows to a present value based upon the discount or premium at purchase.

  There were no significant transfers of financial assets between levels 1 and 2 during the period.

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

See accompanying notes to financial statements.

70

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71

Columbia Acorn Family of Funds

Statements of Assets and Liabilities (Unaudited)

June 30, 2011	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	$	9,331,368		$	4,336,507		$	1,239,910		$	282,220		$	1,158,355		$	—
Affiliated investments, at cost (See Note 4)		2,325,878			85,252			4,479			—			368,957			118,332
Repurchase agreements, at cost		534,686			226,923			15,821			58,891			94,733			478
Unaffiliated investments, at value (including securities on loan: Columbia Acorn Fund $340,090; Columbia Acorn International $88,468; Columbia Acorn USA $12,520; Columbia Acorn International Select $—; Columbia Acorn Select $59,666; Columbia Thermostat Fund $—)	$	15,285,789		$	6,138,447		$	1,910,189		$	380,651		$	1,719,377		$	—
Affiliated investments, at value (See Note 4)		3,845,216			104,674			3,798			—			286,633			137,677
Repurchase agreements, at value		534,686			226,923			15,821			58,891			94,733			478
Cash		2,224			—	*		—			1			1			1
Foreign currency (cost: Columbia Acorn Fund $2,127; Columbia Acorn International $38,419; Columbia Acorn International Select $525; Columbia Acorn Select $151)		2,150			38,737			—			526			151			—
Net unrealized appreciation on forward foreign currency exchange contracts		—			3,057			—			—			—			—
Receivable for:
Investments sold		46,268			14,133			4,998			—			18,286			174
Fund shares sold		16,431			19,476			1,248			407			1,206			65
Dividends and interest		8,993			6,343			693			329			1,378			—
Securities lending income		200			105			15			8			55			—
Foreign tax reclaims		296			1,706			—			124			—			—
Expense reimbursement due from Adviser		—			—			—			—	*		—			27
Trustees' Deferred Compensation Investments		2,417			687			197			39			250			23
Other assets		147			48			24			3			10			17
Total Assets		19,744,817			6,554,336			1,936,983			440,979			2,122,080			138,462
Liabilities:
Collateral on securities loaned		352,904			90,621			12,944			—			61,634			—
Net unrealized depreciation on forward foreign currency exchange contracts		—			2,796			—			—			—			—
Payable for:
Investments purchased		77,052			9,632			5,767			2,829			8,297			—
Fund shares redeemed		45,467			4,970			3,949			258			4,551			335
Management fee		9,786			3,956			1,299			339			1,340			11
Administration fee		578			197			57			14			62			4
12b-1 Service & Distribution fees		1,591			281			76			26			205			43
Reports to shareholders		821			395			84			74			264			70
Deferred Trustees' fees		2,417			687			197			39			250			23
Transfer agent fees		2,066			354			236			38			356			24
Trustees' fees		18			—			1			—			2			—
Professional fee		140			63			21			22			20			13
Custody fees		75			509			3			32			25			—
Foreign capital gains tax		—			201			—			—			—			—
Other liabilities		43			14			4			9			7			—
Total Liabilities		492,958			114,676			24,638			3,680			77,013			523
Net Assets	$	19,251,859		$	6,439,660		$	1,912,345		$	437,299		$	2,045,067		$	137,939
Composition of Net Assets:
Paid in capital	$	11,501,455		$	4,977,351		$	1,263,898		$	345,003		$	1,567,317		$	143,450
Undistributed/(overdistributed) net investment income (Accumulated net investment loss)		(101,213	)		(102,703	)		(5,413	)		(4,301	)		(53,711	)		1,525
Accumulated net realized gain/(loss)		377,782			(256,826	)		(15,738	)		(1,843	)		52,764			(26,381	)
Net unrealized appreciation/(depreciation) on:
Investments		7,473,759			1,821,362			669,598			98,431			478,698			19,345
Foreign capital gains tax		—			(201	)		—			—			—			—
Foreign currency translations		76			677			—			9			(1	)		—
Net Assets	$	19,251,859		$	6,439,660		$	1,912,345		$	437,299		$	2,045,067		$	137,939
Net asset value per share – Class A (a)	$	30.95		$	41.02		$	30.01		$	28.69		$	27.50		$	12.98
(Net assets/shares)	($3,926,256/126,838)			($908,471/22,149)			($212,735/7,088)			($71,320/2,486)			($509,474/18,526)			($54,090/4,166)
Maximum offering price per share – Class A (b)	$	32.84		$	43.52		$	31.84		$	30.44		$	29.18		$	13.77
(Net asset value per share/front- end sales charge)	($30.95/0.9425)			($41.02/0.9425)			($30.01/0.9425)			($28.69/0.9425)			($27.50/0.9425)			($12.98/0.9425)
Net asset value and offering price per share – Class B (a)	$	28.62		$	39.97	(d)	$	27.79	(d)	$	27.42	(d)	$	25.70		$	13.04
(Net assets/shares)	($188,366/6,581)			($23,575/590)			($7,112/255)			($2,563/93)			($53,225/2,071)			($21,615/1,658)
Net asset value and offering price per share – Class C (a)	$	28.30		$	39.82		$	27.57	(d)	$	27.29		$	25.49	(d)	$	13.02
(Net assets/shares)	($876,147/30,954)			($100,222/2,517)			($36,348/1,319)			($11,463/420)			($87,862/3,446)			($22,788/1,750)
Net asset value and offering price per share – Class I	$	31.96	(d)	$	41.15	(d)	$	31.18	(d)	$	29.00		$	28.25	(d)
(Net assets/shares)	($12,665/396)			($27,769/675)			($3,211/103)			($3/0**)			($8,496/301)
Net asset value and offering price per share – Class Z (c)	$	31.95		$	41.13		$	31.17		$	28.98		$	28.25		$	12.86
(Net assets/shares)	($14,248,425/446,005)			($5,379,623/130,798)			($1,652,939/53,033)			($351,950/12,145)			($1,386,010/49,056)			($39,446/3,068)

(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.

(d)  Due to rounding of shares outstanding.

*  Rounds to less than $500.

**  Rounds to less than 500 shares.

See accompanying notes to financial statements.

72

Columbia Acorn Family of Funds

Statements of Operations (Unaudited)
For the Six Months Ended June 30, 2011

(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	$	62,270		$	84,948		$	4,453		$	5,929		$	6,882		$	—
Dividend income from affiliates (See Note 4)		5,944			2,397			—			—			—			—
Dividends from affiliated investment company shares (See Note 4)		—			—			—			—			—			2,023
Interest income		167			95			4			6			26			—	*
Securitites lending income, net		1,053			454			95			14			131			—
		69,434			87,894			4,552			5,949			7,039			2,023
Foreign taxes withheld		(1,493	)		(7,054	)		(8	)		(471	)		(88	)		—
Total Investment Income		67,941			80,840			4,544			5,478			6,951			2,023
Expenses:
Management fee		59,852			23,819			7,935			2,084			8,907			68
Administration fee		3,530			1,184			349			84			414			26
12b-1 Service and Distribution fees:
Class A		4,732			1,083			271			90			671			60
Class B		903			99			31			11			237			99
Class C		4,258			547			180			58			468			112
Transfer agent fees:
Class A		1,554			593			94			57			276			32
Class B		347			41			14			5			86			28
Class C		472			83			20			12			68			17
Class Z		2,623			1,225			415			57			445			9
Custody fees		649			2,120			28			118			156			—
Trustees' fees		538			176			51			15			66			5
Reports to shareholders		1,018			548			169			70			259			56
Professional fees		559			208			61			32			71			13
Chief compliance officer expenses (See Note 4)		258			79			25			7			34			2
Other expenses		359			168			76			59			97			41
Total expenses		81,652			31,973			9,719			2,759			12,255			568
Less custody fees paid indirectly		—	*		—	*		—	*		—	*		—	*		—
Less reimbursement of expenses by Investment Adviser		—			—			—			—	*		—			(129	)
Net Expenses		81,652			31,973			9,719			2,759			12,255			439
Net Investment Income/(Loss)		(13,711	)		48,867			(5,175	)		2,719			(5,304	)		1,584
Net Realized and Unrealized Gain (Loss) on Portfolio Positions:
Net realized gain/(loss) on:
Unaffiliated investments		381,947			133,208			13,002			34,920			175,643			3,561
Affiliated investments (See Note 4)		11,248			(2,643	)		—			—			(2,797	)		—
Foreign currency transactions and forward foreign currency exchange contracts		146			1,067			—			(52	)		(65	)		—
Distributions from affiliated investment company shares		—			—			—			—			—			156
Net realized gain		393,341			131,632			13,002			34,868			172,781			3,717
Net change in net unrealized appreciation/(depreciation) on:
Unaffiliated investments		507,051			14,580			154,928			(21,427	)		(79,517	)		—
Affiliated investments (See Note 4)		397,583			2,549			504			—			(89,482	)		552
Foreign currency translations and forward foreign currency exchange contracts		46			(11,766	)		—			(3	)		(2	)		—
Foreign capital gains tax		—			306			—			—			—			—
Net change in unrealized appreciation/ (depreciation)		904,680			5,669			155,432			(21,430	)		(169,001	)		552
Net realized and unrealized gain		1,298,021			137,301			168,434			13,438			3,780			4,269
Net Increase/(Decrease) in Net Assets resulting from Operations	$	1,284,310		$	186,168		$	163,259		$	16,157		$	(1,524	)	$	5,853

*  Rounds to less than $500.

See accompanying notes to financial statements.

73

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	(Unaudited) Six months ended June 30,			Year ended December 31,			(Unaudited) Six months ended June 30,			Year ended December 31,			(Unaudited) Six months ended June 30,			Year ended December 31,
(in thousands)	2011			2010 (a)(b)			2011			2010 (a)(b)			2011			2010 (a)(b)
Operations:
Net investment income/(loss)	$	(13,711	)	$	(7,374	)	$	48,867		$	45,340		$	(5,175	)	$	(5,972	)
Net realized gain/(loss) on investments, foreign currency transactions, forward foreign currency exchange contracts and foreign capital gains tax		382,093			971,334			134,275			276,374			13,002			96,553
Net realized gain/(loss) on affiliated investments and distributions from affiliated investment companies and affiliated investment company shares		11,248			139,546			(2,643	)		5,786			—			(1,208	)
Net change in net unrealized appreciation/(depreciation) on investments, foreign currency translations, forward foreign currency exchange contracts and foreign capital gains tax		507,097			1,864,571			3,120			752,452			154,928			224,623
Net change in net unrealized appreciation/(depreciation) on affiliated investment companies and affiliated investment company shares		397,583			758,959			2,549			6,050			504			4,434
Net Increase/(Decrease) from Operations		1,284,310			3,727,036			186,168			1,086,002			163,259			318,430
Distributions to Shareholders From:
Net investment income – Class A		(2,047	)		(2,387	)		(21,972	)		(12,578	)		—			—
Net realized gain – Class A		(38,150	)		(100,919	)		—			—			—			—
Net investment income – Class B		—			—			(600	)		(290	)		—			—
Net realized gain – Class B		(2,204	)		(9,116	)		—			—			—			—
Net investment income – Class C		—			—			(2,369	)		(714	)		—			—
Net realized gain – Class C		(9,366	)		(25,102	)		—			—			—			—
Net investment income – Class I		(34	)		—	*		(676	)		(9	)		—			—
Net realized gain – Class I		(119	)		—	*		—			—			—			—
Net investment income – Class Z		(36,823	)		(18,634	)		(131,455	)		(109,328	)		—			—
Net realized gain – Class Z		(134,735	)		(361,156	)		—			—			—			—
Total Distributions to Shareholders		(223,478	)		(517,314	)		(157,072	)		(122,919	)		—			—
Share Transactions:
Subscriptions – Class A		513,660			843,928			183,011			317,458			24,680			55,029
Distributions reinvested – Class A		36,444			94,158			18,983			10,862			—			—
Redemptions – Class A		(481,606	)		(866,166	)		(107,204	)		(221,501	)		(45,052	)		(59,786	)
Net Increase/(Decrease) – Class A		68,498			71,920			94,790			106,819			(20,372	)		(4,757	)
Subscriptions – Class B		278			989			58			35			4			2
Distributions reinvested – Class B		1,814			7,325			494			260			—			—
Redemptions – Class B		(114,111	)		(312,686	)		(6,359	)		(15,278	)		(2,795	)		(13,951	)
Net Decrease – Class B		(112,019	)		(304,372	)		(5,807	)		(14,983	)		(2,791	)		(13,949	)
Subscriptions – Class C		66,633			76,903			11,504			24,476			1,195			1,669
Distributions reinvested – Class C		7,134			19,273			1,844			590			—			—
Redemptions – Class C		(71,870	)		(145,469	)		(24,543	)		(17,799	)		(3,930	)		(4,671	)
Net Increase/(Decrease) – Class C		1,897			(49,293	)		(11,195	)		7,267			(2,735	)		(3,002	)
Subscriptions – Class I		4,307			13,063			8,133			66,675			10,803			28,852
Distributions reinvested – Class I		153			—			675			9			—			—
Redemptions – Class I		(4,183	)		(1,538	)		(48,107	)		(2,003	)		(38,271	)		(293	)
Net Increase/(Decrease) – Class I		277			11,525			(39,299	)		64,681			(27,468	)		28,559
Subscriptions – Class Z		1,182,084			2,077,687			589,377			1,216,447			234,528			260,284
Distributions reinvested – Class Z		145,609			324,149			91,324			76,344			—			—
Redemptions – Class Z		(1,194,031	)		(1,969,778	)		(433,689	)		(726,019	)		(130,622	)		(276,628	)
Net Increase/(Decrease) – Class Z		133,662			432,058			247,012			566,772			103,906			(16,344	)
Net Increase/(Decrease) from Share Transactions		92,315			161,838			285,501			730,556			50,540			(9,493	)
Redemption Fees		—			—			—			239			—			—
Increase from regulatory settlements (See Note 9)		—			1			—			447			—			—
Total Increase/(Decrease) in Net Assets		1,153,147			3,371,561			314,597			1,694,325			213,799			308,937
Net Assets:
Beginning of period		18,098,712			14,727,151			6,125,063			4,430,738			1,698,546			1,389,609
End of period	$	19,251,859		$	18,098,712		$	6,439,660		$	6,125,063		$	1,912,345		$	1,698,546
Undistributed/(Overdistributed) Net Investment Income or (Accumulated Net Investment Loss)	$	(101,213	)	$	(48,598	)	$	(102,703	)	$	5,502		$	(5,413	)	$	(238	)

(a)  Class I Shares commenced operations on September 27, 2010.

(b)  Class I Shares reflect activity for the period September 27, 2010 through December 31, 2010.

*  Rounds to less than $500.

See accompanying notes to financial statements.

74

	Columbia Acorn International Select						Columbia Acorn Select						Columbia Thermostat Fund
Increase (Decrease) in Net Assets	(Unaudited) Six months ended June 30,			Year ended December 31,			(Unaudited) Six months ended June 30,			Year ended December 31,			(Unaudited) Six months ended June 30,			Year ended December 31,
(in thousands)	2011			2010 (a)(b)			2011			2010 (a)(b)			2011			2010
Operations:
Net investment income/(loss)	$	2,719		$	2,667		$	(5,304	)	$	(11,783	)	$	1,584		$	1,806
Net realized gain/(loss) on investments, foreign currency transactions, forward foreign currency exchange contracts and foreign capital gains tax		34,868			42,527			175,578			59,672			—			—
Net realized gain/(loss) on affiliated investments and distributions from affiliated investment companies and affiliated investment company shares		—			—			(2,797	)		(38,281	)		3,717			(1,976	)
Net change in net unrealized appreciation/(depreciation) on investments, foreign currency translations, forward foreign currency exchange contracts and foreign capital gains tax		(21,430	)		38,193			(79,519	)		283,123			—			—
Net change in net unrealized appreciation/(depreciation) on affiliated investment companies and affiliated investment company shares		—			—			(89,482	)		123,090			552			19,741
Net Increase/(Decrease) from Operations		16,157			83,387			(1,524	)		415,821			5,853			19,571
Distributions to Shareholders From:
Net investment income – Class A		(770	)		(776	)		(7,162	)		—			(625	)		(678	)
Net realized gain – Class A		—			—			—			—			—			—
Net investment income – Class B		(16	)		(25	)		(500	)		—			(249	)		(239	)
Net realized gain – Class B		—			—			—			—			—			—
Net investment income – Class C		(50	)		(65	)		(672	)		—			(191	)		(124	)
Net realized gain – Class C		—			—			—			—			—			—
Net investment income – Class I		—	*		—			(141	)		—			—			—
Net realized gain – Class I		—			—			—			—			—			—
Net investment income – Class Z		(5,052	)		(5,241	)		(22,715	)		—			(473	)		(625	)
Net realized gain – Class Z		—			—			—			—			—			—
Total Distributions to Shareholders		(5,888	)		(6,107	)		(31,190	)		—			(1,538	)		(1,666	)
Share Transactions:
Subscriptions – Class A		10,119			18,214			40,885			115,498			12,599			8,937
Distributions reinvested – Class A		667			675			6,307			—			501			609
Redemptions – Class A		(12,913	)		(23,778	)		(85,032	)		(187,411	)		(5,038	)		(13,847	)
Net Increase/(Decrease) – Class A		(2,127	)		(4,889	)		(37,840	)		(71,913	)		8,062			(4,301	)
Subscriptions – Class B		2			—	*		69			34			45			4
Distributions reinvested – Class B		13			22			391			—			181			218
Redemptions – Class B		(557	)		(1,418	)		(18,583	)		(30,406	)		(8,198	)		(8,516	)
Net Decrease – Class B		(542	)		(1,396	)		(18,123	)		(30,372	)		(7,972	)		(8,294	)
Subscriptions – Class C		636			1,883			2,746			6,743			2,665			3,195
Distributions reinvested – Class C		40			55			495			—			149			109
Redemptions – Class C		(1,405	)		(3,121	)		(12,612	)		(19,302	)		(2,602	)		(5,530	)
Net Increase/(Decrease) – Class C		(729	)		(1,183	)		(9,371	)		(12,559	)		212			(2,226	)
Subscriptions – Class I		—			3			3,155			8,577			—			—
Distributions reinvested – Class I		—			—			141			—			—			—
Redemptions – Class I		—			—			(2,611	)		(931	)		—			—
Net Increase/(Decrease) – Class I		—			3			685			7,646			—			—
Subscriptions – Class Z		28,129			67,172			108,942			358,116			5,619			7,895
Distributions reinvested – Class Z		1,771			1,451			17,488			—			410			560
Redemptions – Class Z		(52,139	)		(96,502	)		(266,855	)		(328,729	)		(3,982	)		(18,853	)
Net Increase/(Decrease) – Class Z		(22,239	)		(27,879	)		(140,425	)		29,387			2,047			(10,398	)
Net Increase/(Decrease) from Share Transactions		(25,637	)		(35,344	)		(205,074	)		(77,811	)		2,349			(25,219	)
Redemption Fees		—			10			—			—			—			—
Increase from regulatory settlements (See Note 9)		—			46			—			—			—			—
Total Increase/(Decrease) in Net Assets		(15,368	)		41,992			(237,788	)		338,010			6,664			(7,314	)
Net Assets:
Beginning of period		452,667			410,675			2,282,855			1,944,845			131,275			138,589
End of period	$	437,299		$	452,667		$	2,045,067		$	2,282,855		$	137,939		$	131,275
Undistributed/(Overdistributed) Net Investment Income or (Accumulated Net Investment Loss)	$	(4,301	)	$	(1,132	)	$	(53,711	)	$	(17,217	)	$	1,525		$	1,479

See accompanying notes to financial statements.

75

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:	(Unaudited) Six months ended June 30,			Year ended December 31,			(Unaudited) Six months ended June 30,			Year ended December 31,			(Unaudited) Six months ended June 30,			Year ended December 31,
(in thousands)	2011			2010 (a)(b)			2011			2010 (a)(b)			2011			2010 (a)(b)
Subscriptions – Class A		17,024			32,735			4,451			8,744			852			2,334
Shares issued in reinvestment – Class A		1,237			3,306			463			325			—			—
Less shares redeemed – Class A		(15,908	)		(34,053	)		(2,601	)		(6,188	)		(1,539	)		(2,521	)
Net Increase/(Decrease) – Class A		2,353			1,988			2,313			2,881			(687	)		(187	)
Subscriptions – Class B		10			38			2			1			—	*		—	*
Shares issued in reinvestment – Class B		66			276			12			9			—			—
Less shares redeemed – Class B		(4,094	)		(13,126	)		(159	)		(444	)		(105	)		(636	)
Net Decrease – Class B		(4,018	)		(12,812	)		(145	)		(434	)		(105	)		(636	)
Subscriptions – Class C		2,406			3,197			288			700			45			76
Shares issued in reinvestment – Class C		265			733			46			19			—			—
Less shares redeemed – Class C		(2,599	)		(6,190	)		(605	)		(519	)		(148	)		(214	)
Net Increase/(Decrease) – Class C		72			(2,260	)		(271	)		200			(103	)		(138	)
Subscriptions – Class I		138			436			196			1,677			361			1,025
Shares issued in reinvestment – Class I		5			—			17			—	*		—			—
Less shares redeemed – Class I		(132	)		(51	)		(1,165	)		(50	)		(1,273	)		(10	)
Net Increase/(Decrease) – Class I		11			385			(952	)		1,627			(912	)		1,015
Subscriptions – Class Z		37,835			78,950			14,274			33,971			7,994			10,643
Shares issued in reinvestment – Class Z		4,790			11,048			2,222			2,239			—			—
Less shares redeemed – Class Z		(38,207	)		(74,926	)		(10,531	)		(20,195	)		(4,340	)		(11,173	)
Net Increase/(Decrease) – Class Z		4,418			15,072			5,965			16,015			3,654			(530	)
Net Increase/(Decrease) in Shares of Beneficial Interest		2,836			2,373			6,910			20,289			1,847			(476	)

(a)  Class I Shares commenced operations on September 27, 2010.

(b)  Class I Shares reflect activity for the period September 27, 2010 through December 31, 2010.

*  Rounds to less than 500.

See accompanying notes to financial statements.

76

	Columbia Acorn International Select						Columbia Acorn Select						Columbia Thermostat Fund
Changes in Shares of Beneficial Interest:	(Unaudited) Six months ended June 30,			Year ended December 31,			(Unaudited) Six months ended June 30,			Year ended December 31,			(Unaudited) Six months ended June 30,			Year ended December 31,
(in thousands)	2011			2010 (a)(b)			2011			2010 (a)(b)			2011			2010
Subscriptions – Class A		355			746			1,468			4,815			977			765
Shares issued in reinvestment – Class A		23			31			242			—			39			56
Less shares redeemed – Class A		(451	)		(982	)		(3,056	)		(7,851	)		(391	)		(1,223	)
Net Increase/(Decrease) – Class A		(73	)		(205	)		(1,346	)		(3,036	)		625			(402	)
Subscriptions – Class B		—	*		—	*		3			2			4			—	*
Shares issued in reinvestment – Class B		—	*		1			16			—			14			21
Less shares redeemed – Class B		(20	)		(62	)		(719	)		(1,342	)		(634	)		(744	)
Net Decrease – Class B		(20	)		(61	)		(700	)		(1,340	)		(616	)		(723	)
Subscriptions – Class C		23			83			106			299			207			275
Shares issued in reinvestment – Class C		1			2			21			—			12			10
Less shares redeemed – Class C		(51	)		(138	)		(492	)		(870	)		(202	)		(485	)
Net Increase/(Decrease) – Class C		(27	)		(53	)		(365	)		(571	)		17			(200	)
Subscriptions – Class I		—			—	*		111			305			—			—
Shares issued in reinvestment – Class I		—			—			5			—			—			—
Less shares redeemed – Class I		—			—			(88	)		(32	)		—			—
Net Increase/(Decrease) – Class I		—			—	*		28			273			—			—
Subscriptions – Class Z		973			2,699			3,786			14,221			443			697
Shares issued in reinvestment – Class Z		61			66			654			—			32			51
Less shares redeemed – Class Z		(1,812	)		(3,845	)		(9,298	)		(13,400	)		(311	)		(1,710	)
Net Increase/(Decrease) – Class Z		(778	)		(1,080	)		(4,858	)		821			164			(962	)
Net Increase/(Decrease) in Shares of Beneficial Interest		(898	)		(1,399	)		(7,241	)		(3,853	)		190			(2,287	)

See accompanying notes to financial statements.

77

Columbia Acorn Family of Funds

Financial Highlights

Columbia Acorn Fund

Class A Shares	(Unaudited) Six months ended June 30,			Year ended December 31,
Selected data for a share outstanding throughout each period	2011			2010			2009			2008			2007			2006
Net Asset Value, Beginning of Period	$	29.24		$	23.98		$	17.22		$	28.87		$	29.02		$	27.57
Income from Investment Operations
Net investment income/(loss) (a)		(0.05	)		(0.06	)		(0.02	)		(0.01	)		0.05	(b)		0.05
Net realized and unrealized gain/(loss)		2.08			6.18			6.78			(10.98	)		2.13			3.82
Total from Investment Operations		2.03			6.12			6.76			(10.99	)		2.18			3.87
Less Distributions to Shareholders
From net investment income		(0.02	)		(0.02	)		—			—			(0.03	)		(0.04	)
From net realized gains		(0.30	)		(0.84	)		—			(0.66	)		(2.30	)		(2.38	)
Total Distributions to Shareholders		(0.32	)		(0.86	)		—			(0.66	)		(2.33	)		(2.42	)
Increase from regulatory settlements		—			0.00	(c)		0.00	(c)		—			—			—
Net Asset Value, End of Period	$	30.95		$	29.24		$	23.98		$	17.22		$	28.87		$	29.02
Total Return (d)		7.00	%(e)		25.61	%		39.26	%		(38.72	)%		7.39	%(f)(g)		14.13	%(f)
Ratios to Average Net Assets/Supplemental Data
Net expenses (h)		1.05	%(i)		1.07	%		1.07	%		1.05	%		1.02	%		1.02	%
Net investment income/(loss) (h)		(0.32	)%(i)		(0.22	)%		(0.12	)%		(0.04	)%		0.17	%		0.17	%
Waiver/reimbursement		—			—			—			—			0.01	%		0.02	%
Portfolio turnover rate		8	%(e)		28	%		27	%		21	%		20	%		22	%
Net assets at end of period (000s)	$	3,926,256		$	3,639,788		$	2,937,761		$	2,221,100		$	4,300,920		$	4,067,868

(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)  Not annualized.

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

(g)  Total return includes a voluntary reimbursement by the Adviser 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.

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

(i)  Annualized.

Class B Shares	(Unaudited) Six months ended June 30,			Year ended December 31,
Selected data for a share outstanding throughout each period	2011			2010			2009			2008			2007			2006
Net Asset Value, Beginning of Period	$	27.14		$	22.43		$	16.21		$	27.39		$	27.78		$	26.61
Income from Investment Operations
Net investment loss (a)		(0.15	)		(0.21	)		(0.14	)		(0.15	)		(0.11	)(b)		(0.13	)
Net realized and unrealized gain/(loss)		1.93			5.76			6.36			(10.37	)		2.02			3.68
Total from Investment Operations		1.78			5.55			6.22			(10.52	)		1.91			3.55
Less Distributions to Shareholders
From net realized gains		(0.30	)		(0.84	)		—			(0.66	)		(2.30	)		(2.38	)
Total Distributions to Shareholders		(0.30	)		(0.84	)		—			(0.66	)		(2.30	)		(2.38	)
Increase from regulatory settlements		—			0.00	(c)		0.00	(c)		—			—			—
Net Asset Value, End of Period	$	28.62		$	27.14		$	22.43		$	16.21		$	27.39		$	27.78
Total Return (d)		6.63	%(e)		24.81	%		38.37	%		(39.11	)%		6.76	%(f)(g)		13.43	%(f)
Ratios to Average Net Assets/Supplemental Data
Net expenses (h)		1.75	%(i)		1.69	%		1.74	%		1.65	%		1.59	%		1.66	%
Net investment loss (h)		(1.05	)%(i)		(0.88	)%		(0.77	)%		(0.64	)%		(0.39	)%		(0.48	)%
Waiver/reimbursement		—			—			—			—			0.01	%		0.02	%
Portfolio turnover rate		8	%(e)		28	%		27	%		21	%		20	%		22	%
Net assets at end of period (000s)	$	188,366		$	287,650		$	525,072		$	581,587		$	1,270,292		$	1,404,165

(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)  Not annualized.

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

(g)  Total return includes a voluntary reimbursement by the Adviser 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.

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

(i)  Annualized.

See accompanying notes to financial statements.

78

Class C Shares	(Unaudited) Six months ended June 30,			Year ended December 31,
Selected data for a share outstanding throughout each period	2011			2010			2009			2008			2007			2006
Net Asset Value, Beginning of Period	$	26.85		$	22.23		$	16.09		$	27.25		$	27.70		$	26.58
Income from Investment Operations
Net investment loss (a)		(0.15	)		(0.24	)		(0.17	)		(0.19	)		(0.18	)(b)		(0.17	)
Net realized and unrealized gain/(loss)		1.90			5.70			6.31			(10.31	)		2.03			3.67
Total from Investment Operations		1.75			5.46			6.14			(10.50	)		1.85			3.50
Less Distributions to Shareholders
From net realized gains		(0.30	)		(0.84	)		—			(0.66	)		(2.30	)		(2.38	)
Total Distributions to Shareholders		(0.30	)		(0.84	)		—			(0.66	)		(2.30	)		(2.38	)
Increase from regulatory settlements		—			0.00	(c)		0.00	(c)		—			—			—
Net Asset Value, End of Period	$	28.30		$	26.85		$	22.23		$	16.09		$	27.25		$	27.70
Total Return (d)		6.59	%(e)		24.63	%		38.16	%		(39.23	)%		6.56	%(f)(g)		13.25	%(f)
Ratios to Average Net Assets/Supplemental Data
Net expenses (h)		1.83	%(i)		1.85	%		1.89	%		1.83	%		1.79	%		1.80	%
Net investment loss (h)		(1.10	)%(i)		(1.00	)%		(0.93	)%		(0.82	)%		(0.60	)%		(0.61	)%
Waiver/reimbursement		—			—			—			—			0.00	%(j)		0.02	%
Portfolio turnover rate		8	%(e)		28	%		27	%		21	%		20	%		22	%
Net assets at end of period (000s)	$	876,147		$	829,181		$	736,818		$	622,665		$	1,312,243		$	1,345,520

(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)  Not annualized.

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

(g)  Total return includes a voluntary reimbursement by the Adviser 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.

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

(i)  Annualized.

(j)  Rounds to less than 0.01%.

Class I Shares	(Unaudited) Six months ended June 30,			Period ended December 31,
Selected data for a share outstanding throughout each period	2011			2010 (a)
Net Asset Value, Beginning of Period	$	30.19		$	26.80
Income from Investment Operations
Net investment income/(loss) (b)		0.00	(c)		(0.01	)
Net realized and unrealized gain		2.16			4.26
Total from Investment Operations		2.16			4.25
Less Distributions to Shareholders
From net investment income		(0.09	)		(0.02	)
From net realized gains		(0.30	)		(0.84	)
Total Distributions to Shareholders		(0.39	)		(0.86	)
Net Asset Value, End of Period	$	31.96		$	30.19
Total Return (d)(e)		7.22	%		15.94	%
Ratios to Average Net Assets/Supplemental Data
Net expenses (f)(g)		0.72	%		0.71	%
Net investment income/(loss) (f)(g)		0.00	%(h)		(0.13	)%
Portfolio turnover rate (e)		8	%		28	%
Net assets at end of period (000s)	$	12,665		$	11,627

(a)  Class I shares commenced operations on September 27, 2010. Per share data and total return reflect activity from that date.

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

(c)  Rounds to less than $0.01.

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

(e)  Not annualized.

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

(g)  Annualized.

(h)  Rounds to less than 0.00%.

See accompanying notes to financial statements.

79

Columbia Acorn Family of Funds

Financial Highlights, continued

Columbia Acorn International

Class A Shares	(Unaudited) Six months ended June 30,			Year ended December 31,
Selected data for a share outstanding throughout each period	2011			2010			2009			2008			2007			2006
Net Asset Value, Beginning of Period	$	40.87		$	34.13		$	23.03		$	43.42		$	40.07		$	33.20
Income from Investment Operations
Net investment income (a)		0.27			0.22			0.23			0.47			0.27			0.23
Net realized and unrealized gain/(loss)		0.90			7.21			11.27			(20.20	)		6.52			10.87
Total from Investment Operations		1.17			7.43			11.50			(19.73	)		6.79			11.10
Less Distributions to Shareholders
From net investment income		(1.02	)		(0.69	)		(0.41	)		(0.06	)		(0.08	)		(0.32	)
From net realized gains		—			—			—			(0.60	)		(3.36	)		(3.91	)
Total Distributions to Shareholders		(1.02	)		(0.69	)		(0.41	)		(0.66	)		(3.44	)		(4.23	)
Redemption Fees
Redemption fees added to paid in capital		—			0.00	(a)(b)		0.00	(a)(b)		0.00	(a)(b)		0.00	(a)(b)		0.00	(a)(b)
Increase from regulatory settlements		—			0.00	(b)		0.01			—			—			—
Net Asset Value, End of Period	$	41.02		$	40.87		$	34.13		$	23.03		$	43.42		$	40.07
Total Return (c)		2.86	%(d)		22.23	%		50.40	%		(46.09	)%		16.90	%(e)		34.16	%(e)
Ratios to Average Net Assets/Supplemental Data
Net expenses (f)		1.29	%(g)		1.35	%		1.36	%		1.31	%		1.23	%		1.24	%
Net investment income (f)		1.31	%(g)		0.62	%		0.85	%		1.36	%		0.60	%		0.61	%
Waiver/reimbursement		—			—			—			—			0.00	%(h)		0.01	%
Portfolio turnover rate		12	%(d)		25	%		31	%		38	%		28	%		31	%
Net assets at end of period (000s)	$	908,471		$	810,603		$	578,599		$	366,820		$	622,901		$	313,401

(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)  Not annualized.

(e)  Had the Adviser 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)  Annualized.

(h)  Rounds to less than 0.01%.

Class B Shares	(Unaudited) Six months ended June 30,			Year ended December 31,
Selected data for a share outstanding throughout each period	2011			2010			2009			2008			2007			2006
Net Asset Value, Beginning of Period	$	39.96		$	33.22		$	22.41		$	42.46		$	39.39		$	32.71
Income from Investment Operations
Net investment income/(loss) (a)		0.11			0.03			0.08			0.27			0.04			(0.00	)(b)
Net realized and unrealized gain/(loss)		0.90			7.02			10.92			(19.72	)		6.39			10.66
Total from Investment Operations		1.01			7.05			11.00			(19.45	)		6.43			10.66
Less Distributions to Shareholders
From net investment income		(1.00	)		(0.31	)		(0.20	)		—			(0.00	)(b)		(0.07	)
From net realized gains		—			—			—			(0.60	)		(3.36	)		(3.91	)
Total Distributions to Shareholders		(1.00	)		(0.31	)		(0.20	)		(0.60	)		(3.36	)		(3.98	)
Redemption Fees
Redemption fees added to paid in capital		—			0.00	(a)(b)		0.00	(a)(b)		0.00	(a)(b)		0.00	(a)(b)		0.00	(a)(b)
Increase from regulatory settlements		—			0.00	(b)		0.01			—			—			—
Net Asset Value, End of Period	$	39.97		$	39.96		$	33.22		$	22.41		$	42.46		$	39.39
Total Return (c)		2.52	%(d)		21.49	%		49.36	%		(46.41	)%		16.25	%(e)		33.26	%(e)
Ratios to Average Net Assets/Supplemental Data
Net expenses (f)		1.96	%(g)		1.96	%		2.03	%		1.90	%		1.81	%		1.89	%
Net investment income/(loss) (f)		0.55	%(g)		0.08	%		0.29	%		0.77	%		0.08	%		(0.01	)%
Waiver/reimbursement		—			—			—			—			0.01	%		0.02	%
Portfolio turnover rate		12	%(d)		25	%		31	%		38	%		28	%		31	%
Net assets at end of period (000s)	$	23,575		$	29,368		$	38,835		$	39,153		$	103,631		$	94,165

(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)  Not annualized.

(e)  Had the Adviser 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)  Annualized.

See accompanying notes to financial statements.

80

Class C Shares	(Unaudited) Six months ended June 30,			Year ended December 31,
Selected data for a share outstanding throughout each period	2011			2010			2009			2008			2007			2006
Net Asset Value, Beginning of Period	$	39.79		$	33.08		$	22.30		$	42.32		$	39.35		$	32.68
Income from Investment Operations
Net investment income/(loss) (a)		0.10			(0.05	)		0.02			0.21			(0.06	)		(0.05	)
Net realized and unrealized gain/(loss)		0.87			7.03			10.89			(19.63	)		6.39			10.66
Total from Investment Operations		0.97			6.98			10.91			(19.42	)		6.33			10.61
Less Distributions to Shareholders
From net investment income		(0.94	)		(0.27	)		(0.14	)		—			(0.00	)(b)		(0.03	)
From net realized gains		—			—			—			(0.60	)		(3.36	)		(3.91	)
Total Distributions to Shareholders		(0.94	)		(0.27	)		(0.14	)		(0.60	)		(3.36	)		(3.94	)
Redemption Fees
Redemption fees added to paid in capital		—			0.00	(a)(b)		0.00	(a)(b)		0.00	(a)(b)		0.00	(a)(b)		0.00	(a)(b)
Increase from regulatory settlements		—			0.00	(b)		0.01			—			—			—
Net Asset Value, End of Period	$	39.82		$	39.79		$	33.08		$	22.30		$	42.32		$	39.35
Total Return (c)		2.45	%(d)		21.34	%		49.12	%		(46.50	)%		16.01	%(e)		33.14	%(e)
Ratios to Average Net Assets/Supplemental Data
Net expenses (f)		2.06	%(g)		2.11	%		2.17	%		2.08	%		1.99	%		2.01	%
Net investment income/(loss) (f)		0.51	%(g)		(0.13	)%		0.07	%		0.60	%		(0.14	)%		(0.14	)%
Waiver/reimbursement		—			—			—			—			0.00	%(h)		0.01	%
Portfolio turnover rate		12	%(d)		25	%		31	%		38	%		28	%		31	%
Net assets at end of period (000s)	$	100,222		$	110,931		$	85,625		$	62,906		$	153,416		$	99,425

(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)  Not annualized.

(e)  Had the Adviser 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)  Annualized.

(h)  Rounds to less than 0.01%.

Class I Shares	(Unaudited) Six months ended June 30,			Period ended December 31,
Selected data for a share outstanding throughout each period	2011			2010 (a)
Net Asset Value, Beginning of Period	$	40.92		$	37.69
Income from Investment Operations
Net investment income (b)		0.27			0.08
Net realized and unrealized gain		0.98			3.49
Total from Investment Operations		1.25			3.57
Less Distributions to Shareholders
From net investment income		(1.02	)		(0.34	)
Rdemption Fees
Redemption fees added to paid in capital		—			0.00	(b)(c)
Net Asset Value, End of Period	$	41.15		$	40.92
Total Return (d)(e)		3.06	%		9.50	%
Ratios to Average Net Assets/Supplemental Data
Net expenses (f)(g)		0.90	%		0.94	%
Net investment income (f)(g)		1.34	%		0.77	%
Portfolio turnover rate (e)		12	%		25	%
Net assets at end of period (000s)	$	27,769		$	66,581

(a)  Class I Shares commenced operations on September 27, 2010. Per share data and total return reflect activity from that date.

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

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

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

(e)  Not annualized.

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

(g)  Annualized.

See accompanying notes to financial statements.

81

Columbia Acorn Family of Funds

Financial Highlights, continued

Columbia Acorn USA

Class A Shares	(Unaudited) Six months ended June 30,			Year ended December 31,
Selected data for a share outstanding throughout each period	2011			2010			2009			2008			2007			2006
Net Asset Value, Beginning of Period	$	27.54		$	22.43		$	15.90		$	27.23		$	28.02		$	26.52
Income from Investment Operations
Net investment loss (a)		(0.11	)		(0.15	)		(0.11	)		(0.14	)		(0.09	)(b)		(0.10	)
Net realized and unrealized gain/(loss)		2.58			5.26			6.64			(10.23	)		1.01			2.21
Total from Investment Operations		2.47			5.11			6.53			(10.37	)		0.92			2.11
Less Distributions to Shareholders
From net realized gains		—			—			—			(0.96	)		(1.71	)		(0.61	)
Increase from regulatory settlements		—			—			0.00	(c)		—			—			—
Net Asset Value, End of Period	$	30.01		$	27.54		$	22.43		$	15.90		$	27.23		$	28.02
Total Return (d)		8.97	%(e)		22.78	%		41.07	%		(39.38	)%		3.18	%(f)(g)		7.95	%(f)
Ratios to Average Net Assets/Supplemental Data
Net expenses (h)		1.28	%(i)		1.30	%		1.32	%		1.29	%		1.25	%		1.26	%
Net investment loss (h)		(0.79	)%(i)		(0.64	)%		(0.64	)%		(0.60	)%		(0.29	)%		(0.35	)%
Waiver/reimbursement		—			—			—			—			0.00	%(j)		0.01	%
Portfolio turnover rate		9	%(e)		32	%		28	%		23	%		21	%		13	%
Net assets at end of period (000s)	$	212,735		$	214,097		$	178,605		$	136,597		$	245,085		$	245,552

(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)  Not annualized.

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

(g)  Total return includes a voluntary reimbursement by the Adviser 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.

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

(i)  Annualized.

(j)  Rounds to less than 0.01%.

Class B Shares	(Unaudited) Six months ended June 30,			Year ended December 31,
Selected data for a share outstanding throughout each period	2011			2010			2009			2008			2007			2006
Net Asset Value, Beginning of Period	$	25.60		$	20.99		$	14.98		$	25.87		$	26.87		$	25.61
Income from Investment Operations
Net investment loss (a)		(0.20	)		(0.30	)		(0.22	)		(0.27	)		(0.25	)(b)		(0.27	)
Net realized and unrealized gain/(loss)		2.39			4.91			6.23			(9.66	)		0.96			2.14
Total from Investment Operations		2.19			4.61			6.01			(9.93	)		0.71			1.87
Less Distributions to Shareholders
From net realized gains		—			—			—			(0.96	)		(1.71	)		(0.61	)
Increase from regulatory settlements		—			—			0.00	(c)		—			—			—
Net Asset Value, End of Period	$	27.79		$	25.60		$	20.99		$	14.98		$	25.87		$	26.87
Total Return (d)		8.55	%(e)		21.96	%		40.12	%		(39.75	)%		2.53	%(f)(g)		7.29	%(f)
Ratios to Average Net Assets/Supplemental Data
Net expenses (h)		2.03	%(i)		1.98	%		2.02	%		1.92	%		1.85	%		1.93	%
Net investment loss (h)		(1.54	)%(i)		(1.37	)%		(1.33	)%		(1.24	)%		(0.87	)%		(1.01	)%
Waiver/reimbursement		—			—			—			—			0.01	%		0.02	%
Portfolio turnover rate		9	%(e)		32	%		28	%		23	%		21	%		13	%
Net assets at end of period (000s)	$	7,112		$	9,222		$	20,903		$	23,633		$	53,820		$	65,040

(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)  Not annualized.

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

(g)  Total return includes a voluntary reimbursement by the Adviser 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.

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

(i)  Annualized.

See accompanying notes to financial statements.

82

Class C Shares	(Unaudited) Six months ended June 30,			Year ended December 31,
Selected data for a share outstanding throughout each period	2011			2010			2009			2008			2007			2006
Net Asset Value, Beginning of Period	$	25.39		$	20.84		$	14.89		$	25.77		$	26.81		$	25.59
Income from Investment Operations
Net investment loss (a)		(0.21	)		(0.31	)		(0.24	)		(0.30	)		(0.30	)(b)		(0.30	)
Net realized and unrealized gain/(loss)		2.39			4.86			6.19			(9.62	)		0.97			2.13
Total from Investment Operations		2.18			4.55			5.95			(9.92	)		0.67			1.83
Less Distributions to Shareholders
From net realized gains		—			—			—			(0.96	)		(1.71	)		(0.61	)
Increase from regulatory settlements		—			—			0.00	(c)		—			—			—
Net Asset Value, End of Period	$	27.57		$	25.39		$	20.84		$	14.89		$	25.77		$	26.81
Total Return (d)		8.59	%(e)		21.83	%		39.96	%		(39.87	)%		2.39	%(f)(g)		7.14	%(f)
Ratios to Average Net Assets/Supplemental Data
Net expenses (h)		2.05	%(i)		2.08	%		2.13	%		2.08	%		2.03	%		2.05	%
Net investment loss (h)		(1.56	)%(i)		(1.41	)%		(1.45	)%		(1.39	)%		(1.07	)%		(1.14	)%
Waiver/reimbursement		—			—			—			—			0.00	%(j)		0.01	%
Portfolio turnover rate		9	%(e)		32	%		28	%		23	%		21	%		13	%
Net assets at end of period (000s)	$	36,348		$	36,101		$	32,508		$	25,899		$	50,743		$	55,306

(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)  Not annualized.

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

(g)  Total return includes a voluntary reimbursement by the Adviser 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.

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

(i)  Annualized.

(j)  Rounds to less than 0.01%.

Class I Shares	(Unaudited) Six months ended June 30,			Period ended December 31,
Selected data for a share outstanding throughout each period	2011			2010 (a)
Net Asset Value, Beginning of Period	$	28.56		$	24.24
Income from Investment Operations
Net investment loss (b)		(0.07	)		(0.03	)
Net realized and unrealized gain		2.69			4.35
Total from Investment Operations		2.62			4.32
Net Asset Value, End of Period	$	31.18		$	28.56
Total Return (c)(d)		9.17	%		17.82	%
Ratios to Average Net Assets/Supplemental Data:
Net expenses (e)(f)		0.94	%		0.94	%
Net investment loss (e)(f)		(0.47	)%		(0.35	)%
Portfolio turnover rate (d)		9	%		32	%
Net assets at end of period (000s)	$	3,211		$	28,993

(a) Class I shares commenced operations on September 27, 2010. Per share data and total return reflect activity from that date.

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

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

(d) Not annualized.

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

(f) Annualized.

See accompanying notes to financial statements.

83

Columbia Acorn Family of Funds

Financial Highlights, continued

Columbia Acorn International Select

Class A Shares	(Unaudited) Six months ended June 30,			Year ended December 31,
Selected data for a share outstanding throughout each period	2011			2010			2009			2008			2007			2006
Net Asset Value, Beginning of Period	$	28.01		$	23.39		$	17.99		$	31.74		$	27.68		$	20.36
Income from Investment Operations
Net investment income (a)		0.14	(b)		0.08			0.10			0.20			0.04	(c)		0.03
Net realized and unrealized gain/(loss)		0.86			4.84			5.43			(13.41	)		5.91			7.29
Total from Investment Operations		1.00			4.92			5.53			(13.21	)		5.95			7.32
Less Distributions to Shareholders
From net investment income		(0.32	)		(0.30	)		(0.15	)		—			(0.12	)		—
From net realized gains		—			—			—			(0.54	)		(1.77	)		—
Total Distributions to Shareholders		(0.32	)		(0.30	)		(0.15	)		(0.54	)		(1.89	)		—
Redemption Fees
Redemption fees added to paid in capital		—			0.00	(a)(d)		0.00	(a)(d)		0.00	(a)(d)		0.00	(a)(d)		0.00	(a)(d)
Increase from regulatory settlements		—			0.00	(d)		0.02			—			—			—
Net Asset Value, End of Period	$	28.69		$	28.01		$	23.39		$	17.99		$	31.74		$	27.68
Total Return (e)		3.55	%(f)		21.41	%		31.01	%		(42.30	)%		21.50	%(g)		35.97	%(g)
Ratios to Average Net Assets/Supplemental Data
Net expenses (h)		1.52	%(i)		1.56	%		1.56	%		1.54	%		1.49	%		1.58	%
Net investment income (h)		0.95	%(i)		0.33	%		0.53	%		0.78	%		0.11	%		0.11	%
Waiver/reimbursement		—			—			—			—			0.00	%(j)		0.02	%
Portfolio turnover rate		21	%(f)		42	%		56	%		68	%		57	%		47	%
Net assets at end of period (000s)	$	71,320		$	71,668		$	64,664		$	46,522		$	48,538		$	22,599

(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 $0.04 per share.

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

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

(e)  Total return at net asset value assuming all distributions reinvested and no initial sales charge or contingent deferred sales charge.

(f)  Not annualized.

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

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

(i)  Annualized.

(j)  Rounds to less than 0.01%.

Class B Shares	(Unaudited) Six months ended June 30,			Year ended December 31,
Selected data for a share outstanding throughout each period	2011			2010			2009			2008			2007			2006
Net Asset Value, Beginning of Period	$	26.72		$	22.34		$	17.16		$	30.50		$	26.73		$	19.80
Income from Investment Operations
Net investment income/(loss) (a)		0.03	(b)		(0.06	)		(0.01	)		0.04			(0.13	)(c)		(0.12	)
Net realized and unrealized gain/(loss)		0.83			4.62			5.17			(12.84	)		5.67			7.05
Total from Investment Operations		0.86			4.56			5.16			(12.80	)		5.54			6.93
Less Distributions to Shareholders
From net investment income		(0.16	)		(0.18	)		—			—			—			—
From net realized gains		—			—			—			(0.54	)		(1.77	)		—
Total Distributions to Shareholders		(0.16	)		(0.18	)		—			(0.54	)		(1.77	)		—
Redemption Fees
Redemption fees added to paid in capital		—			0.00	(a)(d)		0.00	(a)(d)		0.00	(a)(d)		0.00	(a)(d)		0.00	(a)(d)
Increase from regulatory settlements		—			0.00	(d)		0.02			—			—			—
Net Asset Value, End of Period	$	27.42		$	26.72		$	22.34		$	17.16		$	30.50		$	26.73
Total Return (e)		3.21	%(f)(g)		20.63	%(g)		30.19	%(g)		(42.68	)%		20.69	%(g)		35.00	%(g)
Ratios to Average Net Assets/Supplemental Data
Net expenses (h)		2.20	%(i)		2.20	%		2.20	%		2.17	%		2.10	%		2.25	%
Net investment income/(loss) (h)		0.26	%(i)		(0.27	)%		(0.05	)%		0.16	%		(0.45	)%		(0.53	)%
Waiver/reimbursement		0.03	%(i)		0.04	%		0.12	%		—			0.01	%		0.04	%
Portfolio turnover rate		21	%(f)		42	%		56	%		68	%		57	%		47	%
Net assets at end of period (000s)	$	2,563		$	3,030		$	3,887		$	4,444		$	11,941		$	9,787

(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 $0.04 per share.

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

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

(e)  Total return at net asset value assuming all distributions reinvested and no contingent deferred sales charge.

(f)  Not annualized.

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

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

(i)  Annualized.

See accompanying notes to financial statements.

84

Class C Shares	(Unaudited) Six months ended June 30,			Year ended December 31,
Selected data for a share outstanding throughout each period	2011			2010			2009			2008			2007			2006
Net Asset Value, Beginning of Period	$	26.58		$	22.21		$	17.08		$	30.42		$	26.70		$	19.80
Income from Investment Operations
Net investment income/(loss) (a)		0.02	(b)		(0.10	)		(0.06	)		0.00	(c)		(0.20	)(d)		(0.15	)
Net realized and unrealized gain/(loss)		0.81			4.60			5.17			(12.80	)		5.69			7.05
Total from Investment Operations		0.83			4.50			5.11			(12.80	)		5.49			6.90
Less Distributions to Shareholders
From net investment income		(0.12	)		(0.13	)		—			—			—			—
From net realized gains		—			—			—			(0.54	)		(1.77	)		—
Total Distributions to Shareholders		(0.12	)		(0.13	)		—			(0.54	)		(1.77	)		—
Redemption Fees
Redemption fees added to paid in capital		—			0.00	(a)(b)		0.00	(a)(b)		0.00	(a)(b)		0.00	(a)(b)		0.00	(a)(b)
Increase from regulatory settlements		—			0.00	(b)		0.02			—			—			—
Net Asset Value, End of Period	$	27.29		$	26.58		$	22.21		$	17.08		$	30.42		$	26.70
Total Return (e)		3.12	%(f)		20.45	%		30.04	%		(42.79	)%		20.53	%(g)		34.85	%(g)
Ratios to Average Net Assets/Supplemental Data
Net expenses (h)		2.33	%(i)		2.36	%		2.42	%		2.34	%		2.29	%		2.38	%
Net investment income/(loss) (h)		0.14	%(i)		(0.45	)%		(0.30	)%		0.01	%		(0.68	)%		(0.67	)%
Waiver/reimbursement		—			—			—			—			0.01	%		0.02	%
Portfolio turnover rate		21	%(f)		42	%		56	%		68	%		57	%		47	%
Net assets at end of period (000s)	$	11,463		$	11,885		$	11,096		$	9,747		$	13,023		$	7,060

(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 $0.04 per share.

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

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

(e)  Total return at net asset value assuming all distributions reinvested and no contingent deferred sales charge.

(f)  Not annualized.

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

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

(i)  Annualized.

Class I Shares	(Unaudited) Six months ended June 30,			Period ended December 31,
Selected data for a share outstanding throughout each period	2011			2010 (a)
Net Asset Value, Beginning of Period	$	28.33		$	26.11
Income from Investment Operations
Net investment income (b)		0.21	(c)		0.03
Net realized and unrealized gain		0.88			2.19
Total from Investment Operations		1.09			2.22
Less Distributions to Shareholders
From net investment income		(0.42	)		—
Net Asset Value, End of Period	$	29.00		$	28.33
Total Return (d)(e)		3.83			8.50	%
Ratios to Average Net Assets/Supplemental Data:
Net expenses (f)(g)		1.00	%		1.14	%
Net investment income (f)(g)		1.48	%		0.44	%
Portfolio turnover rate (e)		21	%		42	%
Net assets at end of period (000s)	$	3		$	3

(a) Class I shares commenced operations on September 27, 2010. Per share data and total return reflect activity from that date.

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

(c) Net investment income per share includes special dividends. The effect of these dividends amounted to $0.04 per share.

(d) Total return at net asset value assuming all distributions reinvested and no contingent deferred sales charge.

(e) Not annualized.

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

(g) Annualized.

See accompanying notes to financial statements.

85

Columbia Acorn Family of Funds

Financial Highlights, continued

Columbia Acorn Select

Class A Shares	(Unaudited) Six months ended June 30,			Year ended December 31,
Selected data for a share outstanding throughout each period	2011			2010			2009			2008			2007			2006
Net Asset Value, Beginning of Period	$	27.94		$	22.81		$	13.77		$	27.89		$	26.18		$	22.47
Income from Investment Operations
Net investment loss (a)		(0.09	)		(0.18	)		(0.14	)		(0.18	)		(0.15	)		(0.13	)
Net realized and unrealized gain/(loss)		0.03			5.31			9.18			(13.25	)		2.50			4.45
Total from Investment Operations		(0.06	)		5.13			9.04			(13.43	)		2.35			4.32
Less Distributions to Shareholders
From net investment income		(0.38	)		—			—			—			—			(0.02	)
From net realized gains		—			—			—			(0.69	)		(0.64	)		(0.59	)
Total Distributions to Shareholders		(0.38	)		—			—			(0.69	)		(0.64	)		(0.61	)
Net Asset Value, End of Period	$	27.50		$	27.94		$	22.81		$	13.77		$	27.89		$	26.18
Total Return (b)		(0.12	)%(c)		22.49	%		65.65	%		(49.31	)%(d)		8.92	%(e)		19.32	%(e)
Ratios to Average Net Assets/Supplemental Data
Net expenses (f)		1.26	%(g)		1.28	%		1.30	%		1.24	%		1.19	%		1.24	%
Net investment loss (f)		(0.63	)%(g)		(0.73	)%		(0.78	)%		(0.80	)%		(0.52	)%		(0.54	)%
Waiver/reimbursement		—			—			—			—			0.00	%(h)		0.03	%
Portfolio turnover rate		13	%(c)		28	%		19	%		28	%		14	%		21	%
Net assets at end of period (000s)	$	509,474		$	555,263		$	522,443		$	395,794		$	1,117,941		$	940,857

(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)  Not annualized.

(d)  Total return includes a voluntary reimbursement by the Adviser 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.

(e)  Had the Adviser 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)  Annualized.

(h)  Rounds to less than 0.01%.

Class B Shares	(Unaudited) Six months ended June 30,			Year ended December 31,
Selected data for a share outstanding throughout each period	2011			2010			2009			2008			2007			2006
Net Asset Value, Beginning of Period	$	26.06		$	21.41		$	13.02		$	26.57		$	25.13		$	21.71
Income from Investment Operations
Net investment loss (a)		(0.17	)		(0.31	)		(0.24	)		(0.31	)		(0.31	)		(0.28	)
Net realized and unrealized gain/(loss)		0.04			4.96			8.63			(12.55	)		2.39			4.29
Total from Investment Operations		(0.13	)		4.65			8.39			(12.86	)		2.08			4.01
Less Distributions to Shareholders
From net investment income		(0.23	)		—			—			—			—			—
From net realized gains		—			—			—			(0.69	)		(0.64	)		(0.59	)
Total Distributions to Shareholders		(0.23	)		—			—			(0.69	)		(0.64	)		(0.59	)
Net Asset Value, End of Period	$	25.70		$	26.06		$	21.41		$	13.02		$	26.57		$	25.13
Total Return (b)		(0.46	)%(c)		21.72	%		64.44	%		(49.62	)%(d)		8.22	%(e)		18.54	%(e)
Ratios to Average Net Assets/Supplemental Data
Net expenses (f)		1.93	%(g)		1.92	%		2.01	%		1.87	%		1.79	%		1.91	%
Net investment loss (f)		(1.32	)%(g)		(1.39	)%		(1.49	)%		(1.43	)%		(1.12	)%		(1.21	)%
Waiver/reimbursement		—			—			—			—			0.01	%		0.03	%
Portfolio turnover rate		13	%(c)		28	%		19	%		28	%		14	%		21	%
Net assets at end of period (000s)	$	53,225		$	72,203		$	88,004		$	73,152		$	199,182		$	214,260

(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)  Not annualized.

(d)  Total return includes a voluntary reimbursement by the Adviser 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.

(e)  Had the Adviser 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)  Annualized.

See accompanying notes to financial statements.

86

Class C Shares	(Unaudited) Six months ended June 30,			Year ended December 31,
Selected data for a share outstanding throughout each period	2011			2010			2009			2008			2007			2006
Net Asset Value, Beginning of Period	$	25.83		$	21.25		$	12.94		$	26.46		$	25.07		$	21.69
Income from Investment Operations
Net investment loss (a)		(0.18	)		(0.34	)		(0.26	)		(0.34	)		(0.36	)		(0.31	)
Net realized and unrealized gain/(loss)		0.03			4.92			8.57			(12.49	)		2.39			4.28
Total from Investment Operations		(0.15	)		4.58			8.31			(12.83	)		2.03			3.97
Less Distributions to Shareholders
From net investment income		(0.19	)		—			—			—			—			—
From net realized gains		—			—			—			(0.69	)		(0.64	)		(0.59	)
Total Distributions to Shareholders		(0.19	)		—			—			(0.69	)		(0.64	)		(0.59	)
Net Asset Value, End of Period	$	25.49		$	25.83		$	21.25		$	12.94		$	26.46		$	25.07
Total Return (b)		(0.53	)%(c)		21.55	%		64.22	%		(49.71	)%(d)		8.04	%(e)		18.37	%(e)
Ratios to Average Net Assets/Supplemental Data
Net expenses (f)		2.06	%(g)		2.07	%		2.14	%		2.04	%		1.98	%		2.04	%
Net investment loss (f)		(1.42	)%(g)		(1.52	)%		(1.62	)%		(1.60	)%		(1.31	)%		(1.34	)%
Waiver/reimbursement		—			—			—			—			0.00	%(h)		0.03	%
Portfolio turnover rate		13	%(c)		28	%		19	%		28	%		14	%		21	%
Net assets at end of period (000s)	$	87,862		$	98,445		$	93,121		$	70,962		$	197,100		$	173,152

(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)  Not annualized.

(d)  Total return includes a voluntary reimbursement by the Adviser 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.

(e)  Had the Adviser 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)  Annualized.

(h)  Rounds to less than 0.01%.

Class I Shares	(Unaudited) Six months ended June 30,			Period ended December 31,
Selected data for a share outstanding throughout each period	2011			2010 (a)
Net Asset Value, Beginning of Period	$	28.74		$	24.74
Income from Investment Operations
Net investment income/(loss) (b)		(0.04	)		0.01
Net realized and unrealized gain		0.02			3.99
Total from Investment Operations		(0.02	)		4.00
Less Distributions to Shareholders
From net investment income		(0.47	)		—
Net Asset Value, End of Period	$	28.25		$	28.74
Total Return (c)(d)		0.04	%		16.17	%
Ratios to Average Net Assets/Supplemental Data
Net expenses (e)(f)		0.91	%		0.91	%
Net investment income/(loss) (e)(f)		(0.26	)%		0.18	%
Portfolio turnover rate (d)		13	%		28	%
Net assets at end of period (000s)	$	8,496		$	7,832

(a)  Class I Shares commenced operations on September 27, 2010. Per share data and total return reflect activity from that date.

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

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

(d)  Not annualized.

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

(f)  Annualized.

See accompanying notes to financial statements.

87

Columbia Acorn Family of Funds

Financial Highlights, continued

Columbia Thermostat Fund

Class A Shares	(Unaudited) Six months ended June 30,			Year ended December 31,
Selected data for a share outstanding throughout each period	2011			2010			2009			2008			2007			2006
Net Asset Value, Beginning of Period	$	12.58		$	10.90		$	8.26		$	12.31		$	12.59		$	12.49
Income from Investment Operations
Net investment income (a)		0.16			0.19			0.11			0.22			0.49			0.45
Net realized and unrealized gain/(loss)		0.40			1.67			2.53			(3.98	)		0.53			0.84
Total from Investment Operations		0.56			1.86			2.64			(3.76	)		1.02			1.29
Less Distributions to Shareholders
From net investment income		(0.16	)		(0.18	)		(0.00	)(b)		(0.22	)		(0.51	)		(0.47	)
From net realized gains		—			—			—			(0.07	)		(0.79	)		(0.72	)
Total Distributions to Shareholders		(0.16	)		(0.18	)		(0.00	)(b)		(0.29	)		(1.30	)		(1.19	)
Net Asset Value, End of Period	$	12.98		$	12.58		$	10.90		$	8.26		$	12.31		$	12.59
Total Return (c)(d)		4.44	%(e)		17.28	%		31.98	%		(30.67	)%		8.19	%		10.56	%
Ratios to Average Net Assets/Supplemental Data
Net expenses (f)(g)		0.50	%(h)		0.50	%		0.50	%		0.50	%		0.50	%		0.50	%
Net investment income (g)		2.56	%(h)		1.64	%		1.17	%		1.99	%		3.75	%		3.53	%
Waiver/reimbursement		0.20	%(h)		0.22	%		0.28	%		0.18	%		0.18	%		0.20	%
Portfolio turnover rate		36	%(e)		118	%		17	%		130	%		128	%		66	%
Net assets at end of period (000s)	$	54,090		$	44,527		$	42,976		$	41,032		$	53,246		$	58,013

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

(e)  Not annualized.

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

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

(h)  Annualized.

Class B Shares	(Unaudited) Six months ended June 30,			Year ended December 31,
Selected data for a share outstanding throughout each period	2011			2010			2009			2008			2007			2006
Net Asset Value, Beginning of Period	$	12.64		$	10.93		$	8.32		$	12.38		$	12.62		$	12.51
Income from Investment Operations
Net investment income (a)		0.12			0.13			0.06			0.16			0.42			0.38
Net realized and unrealized gain/(loss)		0.42			1.67			2.55			(4.00	)		0.54			0.84
Total from Investment Operations		0.54			1.80			2.61			(3.84	)		0.96			1.22
Less Distributions to Shareholders
From net investment income		(0.14	)		(0.09	)		—			(0.15	)		(0.41	)		(0.39	)
From net realized gains		—			—			—			(0.07	)		(0.79	)		(0.72	)
Total Distributions to Shareholders		(0.14	)		(0.09	)		—			(0.22	)		(1.20	)		(1.11	)
Net Asset Value, End of Period	$	13.04		$	12.64		$	10.93		$	8.32		$	12.38		$	12.62
Total Return (b)(c)		4.28	%(d)		16.64	%		31.37	%		(31.10	)%		7.71	%		9.91	%
Ratios to Average Net Assets/Supplemental Data
Net expenses (e)(f)		1.00	%(g)		1.00	%		1.00	%		1.00	%		1.00	%		1.06	%
Net investment income (f)		1.87	%(g)		1.10	%		0.64	%		1.45	%		3.25	%		2.99	%
Waiver/reimbursement		0.28	%(g)		0.28	%		0.32	%		0.20	%		0.19	%		0.23	%
Portfolio turnover rate		36	%(d)		118	%		17	%		130	%		128	%		66	%
Net assets at end of period (000s)	$	21,615		$	28,752		$	32,758		$	36,673		$	67,709		$	72,367

(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 Adviser and/or Transfer Agent not waived fees and/or reimbursed a portion of expenses, total return would have been reduced.

(d)  Not annualized.

(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%.

(g)  Annualized.

See accompanying notes to financial statements.

88

Class C Shares	(Unaudited) Six months ended June 30,			Year ended December 31,
Selected data for a share outstanding throughout each period	2011			2010			2009			2008			2007			2006
Net Asset Value, Beginning of Period	$	12.62		$	10.91		$	8.33		$	12.37		$	12.62		$	12.51
Income from Investment Operations
Net investment income (a)		0.11			0.10			0.03			0.13			0.39			0.36
Net realized and unrealized gain/(loss)		0.40			1.68			2.55			(3.97	)		0.53			0.84
Total from Investment Operations		0.51			1.78			2.58			(3.84	)		0.92			1.20
Less Distributions to Shareholders
From net investment income		(0.11	)		(0.07	)		—			(0.13	)		(0.38	)		(0.37	)
From net realized gains		—			—			—			(0.07	)		(0.79	)		(0.72	)
Total Distributions to Shareholders		(0.11	)		(0.07	)		—			(0.20	)		(1.17	)		(1.09	)
Net Asset Value, End of Period	$	13.02		$	12.62		$	10.91		$	8.33		$	12.37		$	12.62
Total Return (b)(c)		4.06	%(d)		16.43	%		30.97	%		(31.20	)%		7.36	%		9.72	%
Ratios to Average Net Assets/Supplemental Data
Net expenses (e)(f)		1.25	%(g)		1.25	%		1.25	%		1.25	%		1.25	%		1.25	%
Net investment income (f)		1.74	%(g)		0.88	%		0.39	%		1.23	%		3.02	%		2.81	%
Waiver/reimbursement		0.22	%(g)		0.24	%		0.30	%		0.20	%		0.19	%		0.23	%
Portfolio turnover rate		36	%(d)		118	%		17	%		130	%		128	%		66	%
Net assets at end of period (000s)	$	22,788		$	21,866		$	21,090		$	24,383		$	26,908		$	27,375

(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 Adviser and/or Transfer Agent not waived fees and/or reimbursed a portion of expenses, total return would have been reduced.

(d)  Not annualized.

(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%.

(g)  Annualized.

See accompanying notes to financial statements.

89

Columbia Acorn Family of Funds

Notes to Financial Statements (Unaudited)

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 (S&P) 500 Index in relation to predetermined ranges set by Columbia Wanger Asset Management, LLC (the Adviser). 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 five classes of shares: – Class A, Class B, Class C, Class I and Class Z – except Columbia Thermostat Fund, which does not have Class I shares. 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 I shares are offered continuously at net asset value. There are certain restrictions on the purchase of Class I shares.

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.

The financial highlights for the Fund's Class Z shares are presented in a separate semi-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.

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.

>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 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 their 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

90

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.

>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.

A Fund may use forward foreign currency exchange contracts to buy or sell a foreign currency when the Adviser 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, except Columbia Thermostat 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 Adviser 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 as of June 30, 2011 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

91

Columbia Acorn Family of Funds

Notes to Financial Statements (Unaudited), continued

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 daily 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.

>Federal income taxes

It is each Fund's policy to comply with the provisions of the Internal Revenue Code available to regulated investment companies and, in the manner provided therein, distribute substantially 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 remote.

92

3.  Federal Tax Information

The tax character of distributions paid during the year ended December 31, 2010 was as follows:

	Ordinary Income*		Long-Term Capital Gains
(in thousands)
Columbia Acorn Fund	$	21,020	$	496,293
Columbia Acorn International		122,919		—
Columbia Acorn USA		—		—
Columbia Acorn International Select		6,107		—
Columbia Acorn Select		—		—
Columbia Thermostat Fund		1,666		—

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

The following capital loss carryforwards, determined as of December 31, 2010, 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
	2011- 2015		2016		2017		2018		Total
(in thousands)
Columbia Acorn International	$	—	$	—	$	386,385	$	—	$	386,385
Columbia Acorn USA		—		—		28,408		—		28,408
Columbia Acorn International Select		—		—		36,610		—		36,610
Columbia Acorn Select		—		3,592		115,445		—		119,037
Columbia Thermostat Fund		—		5,193		21,738		2,954		29,885

Capital loss carryforwards that were utilized for the Funds during the year ended December 31, 2010 were as follows:

(in thousands)
Columbia Acorn Fund	$	409,911
Columbia Acorn International		238,546
Columbia Acorn USA		85,334
Columbia Acorn International Select		40,289
Columbia Acorn Select		8,679

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 years remain subject to examination by the Internal Revenue Service.

4.  Transactions with Affiliates

Columbia Wanger Asset Management (CWAM) is a wholly owned subsidiary of Columbia Management, which is a wholly owned subsidiary of Ameriprise Financial, Inc. (Ameriprise Financial). CWAM furnishes continuing investment supervision to the Funds and is responsible for the overall management of the Funds' business affairs.

CWAM receives a monthly advisory fee based on each Fund's average daily net assets at the following annual rates:

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	%

93

Columbia Acorn Family of Funds

Notes to Financial Statements (Unaudited), continued

For the six months ended June 30, 2011, the Funds' annualized effective investment advisory fee rates were as follows:

Columbia Acorn Fund	0.64	%
Columbia Acorn International	0.76	%
Columbia Acorn USA	0.86	%
Columbia Acorn International Select	0.94	%
Columbia Acorn Select	0.81	%
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 custodial charges relating to overdrafts, if any) after giving effect to any balance credits from the Funds' custodian, exceeding annually the average daily net assets of the Funds as follows:

Fund	Class A			Class B			Class C			Class I
Columbia Acorn International Select		1.70	%		2.20	%		2.45	%		1.30	%
Columbia Acorn Select		1.60	%		2.10	%		2.35	%		1.25	%

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, 2012. There is no guarantee that this arrangement will continue thereafter.

Expenses reimbursed by CWAM to Columbia Acorn International Select and Columbia Thermostat Fund for the six months ended June 30, 2011, were $363 and $128,651, 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 six months ended June 30, 2011, the annualized effective administration fee rate was 0.04% of each Fund's average daily net assets. CWAM has delegated to Columbia Management responsibility to provide certain sub-administrative services to the Funds.

Columbia Management Investment Distributors, Inc. (CMID), a wholly owned subsidiary of Ameriprise Financial, is the distributor of the Funds.

For the six months ended June 30, 2011, 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 $282 in underwriting discounts in connection with redemptions of Class A shares and received CDSCs of $—*, $48 and $22, 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 CMID 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. CMID receives no compensation with respect to Class Z shares.

Columbia Management Investment Services Corp. (CMIS), a wholly owned subsidiary of Ameriprise Financial, is the transfer agent of the Funds. For its services, each Fund pays CMIS a monthly fee at the annual rate of $17.00 per open account. CMIS also receives reimbursement from the Fund's for certain out-of-pocket expenses. The arrangement with BFDS has been continued by CMIS.

Class I shares do not pay transfer agent fees.

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 of 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

*Rounds to less than $500.

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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, 2010, 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 34, 35, 46, 56 and 68, respectively.

During the six months ended June 30, 2011, the Funds engaged in purchase and sale transactions with funds that have a common investment adviser (or affiliated investment advisers), 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 Fund	$	25,228	$	—
Columbia Acorn International		1,372		—
Columbia Acorn USA		578		—
Columbia Acorn International Select		213		—
Columbia Acorn Select		—		24,857

5.  Objectives and Strategies for Investing in Derivative Instruments

Columbia Acorn International uses derivative 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 risks:

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 note provides 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 seek 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 seek 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 six months ended June 30, 2011, Columbia Acorn International entered into 92 forward foreign currency exchange contracts.

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Columbia Acorn Family of Funds

Notes to Financial Statements (Unaudited), continued

The following table is a summary of the value of Columbia Acorn International's derivative instruments as of June 30, 2011.

    Fair Value of Derivative Instruments

	Asset			Liability
	Statement of Assets and Liabilities	Fair Value		Statement of Assets and Liabilities	Fair Value
(in thousands)
	Unrealized appreciation on forward foreign currency exchange contracts	$	3,057	Unrealized depreciation on forward foreign currency exchange contracts	$	2,796

The effect of derivative instruments on Columbia Acorn International's Statement of Operations for the six months ended June 30, 2011 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	$	(84	)	$	(11,026	)

6.  Borrowing Arrangements

The Trust participates 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 1.25%. In addition, a commitment fee of 0.125% 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 six months ended June 30, 2011. 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 2012.

7.  Investment Transactions

The aggregate cost of purchases and proceeds from sales, other than short-term obligations, for the six months ended June 30, 2011, were:

Columbia Acorn Fund

(in thousands)
Investment securities
Purchases	$	1,566,628
Proceeds from sales		1,538,048

Columbia Acorn International

(in thousands)
Investment securities
Purchases	$	1,008,306
Proceeds from sales		748,658

Columbia Acorn USA

(in thousands)
Investment securities
Purchases	$	209,631
Proceeds from sales		167,239

Columbia Acorn International Select

(in thousands)
Investment securities
Purchases	$	87,027
Proceeds from sales		149,800

Columbia Acorn Select

(in thousands)
Investment securities
Purchases	$	277,833
Proceeds from sales		506,800

Columbia Thermostat Fund

(in thousands)
Investment securities
Purchases	$	49,334
Proceeds from sales		48,426

8.  Regulatory Settlements with Third Parties

During the year ended December 31, 2010, Columbia Acorn International and Columbia Acorn International Select received payments totaling $446,565 and $46,265, 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" in the Statements of Changes in Net Assets.

9.  Information Regarding Pending and Settled Legal Proceedings

In June 2004, an action captioned John E. Gallus et al. v. American Express Financial Corp. and American Express

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Financial Advisors Inc. was filed in the United States District Court for the District of Arizona. The plaintiffs allege that they are investors in several American Express Company (now known as legacy RiverSource) mutual funds and they purport to bring the action derivatively on behalf of those funds under the Investment Company Act of 1940. The plaintiffs allege that fees allegedly paid to the defendants by the funds for investment advisory and administrative services are excessive. The plaintiffs seek remedies including restitution and rescission of investment advisory and distribution agreements. The plaintiffs voluntarily agreed to transfer this case to the United States District Court for the District of Minnesota (the District Court). In response to defendants' motion to dismiss the complaint, the District Court dismissed one of plaintiffs' four claims and granted plaintiffs limited discovery. Defendants moved for summary judgment in April 2007. Summary judgment was granted in the defendants' favor on July 9, 2007. The plaintiffs filed a notice of appeal with the Eighth Circuit Court of Appeals (the Eighth Circuit) on August 8, 2007. On April 8, 2009, the Eighth Circuit reversed summary judgment and remanded to the District Court for further proceedings. On August 6, 2009, defendants filed a writ of certiorari with the U.S. Supreme Court (the Supreme Court), asking the Supreme Court to stay the District Court proceedings while the Supreme Court considers and rules in a case captioned Jones v. Harris Associates, which involves issues of law similar to those presented in the Gallus case. On March 30, 2010, the Supreme Court issued its ruling in Jones v. Harris Associates, and on April 5, 2010, the Supreme Court vacated the Eighth Circuit's decision in the Gallus case and remanded the case to the Eighth Circuit for further consideration in light of the Supreme Court's decision in Jones v. Harris Associates. On June 4, 2010, the Eighth Circuit remanded the Gallus case to the District Court for further consideration in light of the Supreme Court's decision in Jones v. Harris Associates. On December 9, 2010, the District Court reinstated its July 9, 2007 summary judgment order in favor of the defendants. On January 10, 2011, plaintiffs filed a notice of appeal with the Eighth Circuit.

In December 2005, without admitting or denying the allegations, American Express Financial Corporation (AEFC, which is now known as Ameriprise Financial, Inc. (Ameriprise Financial)), entered into settlement agreements with the Securities and Exchange Commission (SEC) and Minnesota Department of Commerce (MDOC) related to market timing activities. As a result, AEFC was censured and ordered to cease and desist from committing or causing any violations of certain provisions of the Investment Advisers Act of 1940, the Investment Company Act of 1940, and various Minnesota laws. AEFC agreed to pay disgorgement of $10 million and civil money penalties of $7 million. AEFC also agreed to retain an independent distribution consultant to assist in developing a plan for distribution of all disgorgement and civil penalties ordered by the SEC in accordance with various undertakings detailed at http://www.sec.gov/litigation/admin/ia-2451.pdf. Ameriprise Financial and its affiliates have cooperated with the SEC and the MDOC in these legal proceedings, and have made regular reports to the RiverSource, Seligman and Threadneedle funds' Boards of Directors/Trustees.

Ameriprise Financial and certain of its affiliates have historically been involved in a number of legal, arbitration and regulatory proceedings, including routine litigation, class actions, and governmental actions, concerning matters arising in connection with the conduct of their business activities. Ameriprise Financial believes that the Funds are not currently the subject of, and that neither Ameriprise Financial nor any of its affiliates are the subject of, any pending legal, arbitration or regulatory proceedings that are likely to have a material adverse effect on the Funds or the ability of Ameriprise Financial or its affiliates to perform under their contracts with the Funds. Ameriprise Financial is required to make 10-Q, 10-K and, as necessary, 8-K filings with the SEC on legal and regulatory matters that relate to Ameriprise Financial and its affiliates. Copies of these filings may be obtained by accessing the SEC website at www.sec.gov.

There can be no assurance that these matters, or the adverse publicity associated with them, will not result in increased fund redemptions, reduced sale of fund shares or other adverse consequences to the Funds. Further, although we believe proceedings are not likely to have a material adverse effect on the Funds or the ability of Ameriprise Financial or its affiliates to perform under their contracts with the Funds, these proceedings are subject to uncertainties and, as such, we are unable to estimate the possible loss or range of loss that may result. An adverse outcome in one or more of these proceedings could result in adverse judgments, settlements, fines, penalties or other relief that could have a material adverse effect on the consolidated financial condition or results of operations of Ameriprise Financial.

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[Excerpt from:]

Columbia Acorn Trust

Management Fee Evaluation of the Senior Officer

Prepared Pursuant to the New York Attorney General's
Assurance of Discontinuance

May 2011

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Introduction

The New York Attorney General's Assurance of Discontinuance (Order) entered into by Columbia Management Advisors, LLC (CMA) and Columbia Management Distributors, Inc., (CMDI) in February 2005, allows CMA to manage or advise a mutual fund only if the trustees of the fund appoint a Senior Officer to perform specified duties and responsibilities. Among these responsibilities is "managing the process by which proposed management fees (including but not limited to, advisory fees) to be charged the [funds] are negotiated so that they are negotiated in a manner which is at arms' length and reasonable and consistent with this Assurance of Discontinuance."

The Columbia Acorn Trust and Wanger Advisors Trust (collectively, the Trusts) and each series thereof (the Acorn funds, WAT funds or collectively, the Funds) are overseen by the same Board of Trustees (Board). The Order provides that this Board must determine the reasonableness of proposed management fees by using either an annual competitive bidding process supervised by the Senior Officer or Independent Fee Consultant, or by obtaining an annual independent written evaluation prepared by or under the direction of the Senior Officer or the Independent Fee Consultant.

Management fees are only part of the costs and expenses paid by mutual fund shareholders. Fund expenses can vary depending upon the class of shares held but usually include: (1) advisory fees to compensate analysts and portfolio managers for stock research and portfolio management, as well as the cost of operating a trading desk; (2) administrative expenses incurred to prepare registration statements and tax returns, calculate the funds' net asset values, maintain effective compliance procedures and perform recordkeeping services; (3) transfer agency costs for establishing accounts, accepting and disbursing funds, as well as overseeing trading in fund shares; (4) custodial expenses incurred to hold the securities purchased by the funds; and (5) distribution expenses, including commissions paid to brokers that sell the fund shares to investors. Management fees consist of (1) and (2), but not the other services.

Columbia Wanger Asset Management, LLC (CWAM), is the adviser to the Funds, and at present is wholly owned by Ameriprise Financial, Inc. (Ameriprise). The name Columbia Management or Columbia, is used to refer to the group of entities that manage or provide services to funds bearing the brand name Columbia. These entities include Columbia Management Investment Advisers, (CMIA), the successor entity to CMA, Columbia Management Investment Services, Inc. (CMIS) and Columbia Management Investment Distributors, Inc. (CMID), the successor entity to CMDI. The Columbia asset management business, formerly owned by Bank of America Corporation (Bank of America), is now owned by Ameriprise.

The Change of Ownership

On September 29, 2009, Bank of America entered into a Purchase Agreement with Ameriprise providing for, among other things, the sale of CWAM to Ameriprise and the acquisition by Ameriprise of certain assets of Columbia. The sale closed on May 1, 2010. A new advisory agreement is required under these circumstances. In advance of that closing, Columbia and Ameriprise proposed that the Trusts continue, in substance, the then existing advisory agreement governing portfolio management, and the administration services agreement governing certain administration and clerical services. They proposed no material changes to these agreements, no change in services and no changes in fee levels, only those changes necessary to effect the change of ownership. The Board of Trustees approved the new advisory agreements, and on May 27, 2010, shareholders voted to approve them too. The investment management team responsible for the Funds remained with CWAM following the Ameriprise acquisition.

The Investment Company Act of 1940 (1940 Act) effectively bars an increase in management fees for two years following a change in ownership of a fund's advisor (other than for bona fide additional investment advisory services); the purpose of this prohibition is to preclude management from financing the purchase through increased advisory fees. Ameriprise has represented to the Board that it intends to comply with these restrictions, and does not seek increased management fees at this time. Rather, Ameriprise seeks only to renew the advisory and related agreements on their existing terms.

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Requirements of the Order

The Order applies to any successor to substantially all the assets of CMDI and CMA. Thus, it applies to CMIA and CMID as successors to CMA and CMDI. Under the Order, a fee evaluation must precede the execution of new or the extension of existing advisory and administration services agreements. The existing agreements continue in effect until July 31, 2011.

In conformity with the terms of the Order and past evaluations, this Evaluation addresses only the advisory and administration contracts, and does not extend to the Funds' underwriting and transfer agency agreements.

According to the Order, the Senior Officer's evaluation must consider a number of factors. These factors parallel the standard set forth in the Gartenberg case. They are following:

(1)  Management fees (including components thereof) charged to institutional and other clients of CWAM for like services;

(2)  Management fees (including any components thereof) charged by other mutual fund companies for like services;

(3)  Costs to CWAM and its affiliates of supplying services pursuant to the management fee agreements, excluding any intra-corporate profit;

(4)  Profit margins of CWAM and its affiliates from supplying such services;

(5)  Possible economies of scale as the Funds grow larger; and

(6)  The nature and quality of CWAM's services, including the performance of each Fund.

In 2004, the Boards of the two Trusts, then separate groups, each appointed me Senior Officer under the Order. They also determined not to pursue a competitive bidding process and instead, charged me with the responsibility of evaluating the Funds' proposed advisory and administration fee contracts with CWAM in conformity with the requirements of the Order. In discharging their responsibilities, the independent Trustees have also consulted independent, outside counsel. The Board has asked that I prepare this Evaluation.

Scope of this Evaluation

This Evaluation is qualified in two respects. First, assessing such factors as cost of service, profitability, projected economies of scale, and expected quality of service, involves, at present, a significant element of uncertainty. Ameriprise and Columbia hope to effect cost savings by virtue of the increased scale of their operations. The integration of the two organizations is not, however, complete at this time, so the anticipated benefits are impossible to quantify now and hence cannot effectively be weighed in assessing the reasonableness of the proposed management fee. Profitability data is, to some extent, based on pro forma financial statements. At the same time, Ameriprise and Columbia have assured the Board that the Funds will not suffer diminished services as a result of the combination, nor do they propose to change the fee levels set forth in the existing advisory and administration services agreements. The upshot is that the Fund shareholders will, if the advisory agreements are renewed and asset levels do not decrease, pay no more than they do now, but it is too early to determine whether the change in ownership will result in material changes in the calculus of assessing the fairness of the management fee. Of necessity this must be left to future evaluations.

A second consideration concerns the new funds recently approved by the Board of Trustees. Earlier this year, CWAM and Ameriprise proposed two new Acorn funds: Columbia Acorn Emerging Markets Fund (Acorn Emerging Markets), and Columbia Acorn European Fund (Acorn European). I issued a fee evaluation in February 2011 addressing the management fees proposed for those new funds. In March 2011, the Board approved amendments to the advisory and other agreements necessary to launch the new funds. They have not yet, however, been offered. Consequently, there is nothing to add here to the evaluation done in February, so this Evaluation does not address those funds.

Process and Independence

The objectives of the Order are to ensure the independent evaluation of the management fees paid by the Funds as well as to insure that all relevant factors are considered. In my view, this contract process has been conducted at arms-length and with

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independence in gathering, considering and evaluating all relevant data. At the outset of the process, the Trustees sought and obtained from Ameriprise and Columbia a comprehensive compilation of data regarding Fund performance and expenses, adviser profitability, and other information. The Trustees, acting through their Contract Committee evaluated this information thoroughly, and met often to discuss it. Performance and expense data was obtained from both Morningstar and Lipper, the leading consultants in this area. The rankings prepared by Morningstar and Lipper were independent and prepared in conformity with the methodologies employed by those organizations. Counsel for the Funds and the Independent Trustees considered, as did I, the terms and conditions of the proposed contracts.

My evaluation of the advisory contracts was shaped, as it has been in the past, by my experience as Chief Compliance Officer of the Trusts (CCO). As CCO, I report solely to the Board and have no reporting obligation to, or employment relationship with, Ameriprise or its affiliates. I have commented on compliance matters in evaluating the quality of service provided by CWAM.

This Report, its supporting materials and the data contained in other materials submitted to the Contract Committee, in my view, provide a thorough factual basis upon which the Board, in consultation with independent counsel as it deems appropriate, may conduct management fee negotiations that are in the best interests of the Funds' shareholders.

The Fee Reductions Mandated under the Order

Under the terms of the Order, Columbia agreed to secure certain management fee reductions for the mutual funds advised by its affiliate investment advisers. In some instances, breakpoints were also established. Although neither CWAM nor the Trusts was a party to the Order, CWAM offered and the Board accepted certain advisory fee reductions during 2005. By the terms of the Order, these fees could not be increased before November 30, 2009, and, in fact, have not been increased since. As a result of the Ameriprise acquisition, the Investment Company Act precludes any increases in management fees before May 2012 (other than for bona fide additional investment advisory services). Therefore, CWAM and Ameriprise propose the continuation of the contracts and management fees as they now exist; no increases in these fees are sought, and no reductions offered.

Conclusions

My review of the data and other material above leads to the following conclusions with respect to the factors identified in the Order.

A.  Fund Performance

The Domestic Funds: The Acorn Fund has achieved good performance over the past five years, and excellent results over longer periods. Acorn Select and Wanger Select have enjoyed better than average investment returns over the past five years, but have suffered reversals in more recent periods. Both funds expose investors to greater relative risk than the other domestic Funds. Acorn USA and its parallel, Wanger USA are the weakest performers, falling behind their benchmark and peer medians over one and five years. Thermostat is unique and therefore difficult to assess, but has outperformed its benchmark and now enjoys strong rankings from Morningstar.

The International Funds: The international Funds have delivered excellent results over the past five years, and done so while exposing investors to less risk than competing funds. They have also outperformed their benchmarks during this period, but recent results have been more restrained. The international Funds enjoy positive "alpha," confirming the value of their portfolio managers.

B.  Management Fees Relative to Peers

  There is significant variance in management fee rankings across the Funds. Acorn International is the only fund that was ranked in the top quartile by both Morningstar and Lipper. The other Acorn funds tend to fall around the medians identified by one or the other service. The WAT funds are uniformly more expensive than their peers.

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C.  Management Fees Relative to Institutional Account and Other Mutual Fund Accounts

  CWAM's focus is on its mutual funds. The few institutional accounts it does manage vary in rate structures. Some pay advisory fees commensurate with or higher than the Acorn and WAT funds. In a few instances, however, institutional accounts pay lower advisory fees than do the Acorn funds. One such institutional account is significant in size and has been under CWAM's management for over 33 years. Furthermore, CWAM performs sub-advisory services for mutual funds managed by Ameriprise affiliates, CWAM's parent organization, at rates that are lower than those paid by the parallel Acorn funds, though sub-advisory services usually differ from those necessary for the full support of a mutual fund.

D.  Administrative Services

  The Acorn and WAT funds' administrative fees are within the range of fees charged by competitors, but these rankings suffer from a lack of uniformity in the scope of services encompassed by the fee. CWAM provides excellent administrative support for all the Funds.

E.  Costs and Benefits to CWAM and its Affiliates

  CWAM's direct costs do not appear excessive. Overhead and indirect costs allocated to CWAM by its parent organization, however, are significant and have varied considerably over the years. CWAM's affiliates report operating losses and although the allocations leading to these losses may bear closer scrutiny, Ameriprise affiliates do not appear to enjoy excessive "fall out" benefits from CWAM's advisory agreement with the Funds. CWAM continues, however, to enjoy substantial benefits from the use of "soft dollar" payments for research.

F.  Profitability

  CWAM's profit margins may be in the upper range of its competitors, but peer profitability is difficult to assess given differences in products, operations and other factors. Furthermore, there is limited public information available with regard to the profitability of investment advisers.

G.  Economies of Scale

  Economies of scale do exist at CWAM, and the Board has instituted breakpoints that reduce fess as assets increase. Though asset levels have recovered from recent lows, sustained asset growth will be required to trigger additional fee reductions under the current schedule.

H.  Nature and Quality of Service

  This category includes a variety of considerations that are difficult to quantify, yet can have a significant bearing on the performance of the Acorn and WAT funds. Several areas merit comment: (1) CWAM has maintained its investment management capacity and an experienced staff; and (2) CWAM has a reasonably designed compliance program that protects shareholders.

I.  Process

  In my opinion, the process of negotiating an advisory contract for the Funds has been conducted thoroughly and at arms' length. The Board's Contract Committee has sought and obtained extensive data bearing on the reasonableness of the management fees proposed by CWAM. The Trustees have sufficient information to evaluate management's proposal, and negotiate contract terms that are in the best interests of fund shareholders.

Recommendation

According to Morningstar, Acorn USA and Wanger USA have delivered performance below peer medians for the past one and five years, while imposing management fees that exceed them. Management has fashioned various initiatives to improve performance, and the Trustees should continue to monitor both Funds closely to assess the impact of those initiatives.

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Board Approval of the Advisory Agreement

Columbia Acorn Trust (the Trust) has an investment advisory agreement (the Advisory Agreement) with Columbia Wanger Asset Management, LLC (CWAM) under which CWAM manages the Columbia Acorn Funds (the Funds). More than 75% of the trustees of the Trust (the Trustees) are comprised of persons who have no direct or indirect interest in the Advisory Agreement and are not interested persons (as defined in the Investment Company Act of 1940, as amended (the 1940 Act)) of the Trust (the Independent Trustees). The Trustees oversee the management of each Fund and, as required by law, determine at least annually whether to continue the Advisory Agreement for each Fund.

The Contract Committee of the Board (the Committee), which is comprised solely of Independent Trustees, makes recommendations to the Board regarding any proposed continuation of the Advisory Agreement. After the Committee has made its recommendations, the full Board determines whether to approve continuation of the Advisory Agreement. The Board also considers matters bearing on the Advisory Agreement at its various meetings throughout the year, meets at least quarterly with CWAM's portfolio managers and receives monthly reports from CWAM on the performance of the Funds.

In connection with their most recent consideration of the Advisory Agreement for each Fund, the Committee and all Trustees received and reviewed a substantial amount of information provided by CWAM, Columbia Management Investment Advisers, LLC (Columbia Management) and Ameriprise Financial, Inc. (Ameriprise), in response to written requests from the Independent Trustees and their independent legal counsel. Throughout the process, the Trustees had numerous opportunities to ask questions of and request additional materials from CWAM, Columbia Management and Ameriprise.

During each meeting at which the Committee or the Independent Trustees considered the Advisory Agreement, they met in executive session with their independent legal counsel. The Committee also met with representatives of CWAM, Columbia Management and Ameriprise on several occasions. In all, the Committee convened formally on five separate occasions to consider the continuation of the Advisory Agreement. The Board and/or some or all of the Independent Trustees met on other occasions to receive the Committee's status reports, receive presentations from CWAM, Columbia Management and Ameriprise representatives, and to discuss outstanding issues. In addition, the Investment Performance Analysis Committee of the Board, also comprised exclusively of Independent Trustees, reviewed the performance of the Funds and presented its findings to the Board and the Committee throughout the year. The Compliance Committee also provided information to the Committee with respect to relevant matters.

The Trustees reviewed the Advisory Agreement, as well as certain information obtained through CWAM's, Columbia Management's and Ameriprise's responses to independent legal counsel's questionnaires. In addition, the Trustees reviewed the Management Fee Evaluation dated May 2011 (the Fee Evaluation) prepared by the Trust's chief compliance officer, senior vice president and general counsel, who also serves as the Trust's "Senior Officer," as contemplated by the Assurance of Discontinuance dated February 9, 2005 among former affiliates of CWAM and the Office of the New York Attorney General. A summary of the Fee Evaluation is included in this report.

The materials reviewed by the Committee and the Trustees included, among other items, (i) information on the investment performance of each Fund and of independently selected peer groups of funds and of the Funds' performance benchmarks over various time periods, (ii) information on each Fund's advisory fees and other expenses, including information comparing the Fund's fees and expenses to those of peer groups of funds and information about any applicable expense limitations and fee breakpoints, (iii) data on sales and redemptions of Fund shares, and (iv) information on the profitability to CWAM and Ameriprise, as well as potential "fall-out" or ancillary benefits that CWAM and its affiliates may receive as a result of their relationships with the Funds. The Trustees also considered other information such as (i) CWAM's financial condition, (ii) each Fund's investment objective and strategy, (iii) the size, education and experience of CWAM's investment staff and its use of technology, external research and trading cost measurement tools, (iv) the portfolio manager compensation framework, (v) the allocation of the Funds' brokerage, and the use of "soft" commission dollars to pay for research products and services, and (vi) the resources devoted to, and the record of compliance with, the Funds' investment policies and restrictions, policies on personal securities transactions and other compliance policies.

At a meeting held on June 8, 2011, upon recommendations of the Committee, the Board of Trustees unanimously approved the continuation of the Advisory Agreement.

In considering the continuation of the Advisory Agreement, the Trustees reviewed and analyzed various factors that they determined were relevant, none of which by itself was considered dispositive. The material factors and conclusions that formed the basis for the Trustees' determination to approve the continuation of the Advisory Agreement are discussed below.

Nature, quality and extent of services. The Trustees reviewed the nature, quality and extent of the services provided by CWAM and its affiliates to the Funds under the Advisory Agreement, taking into account the investment objective and strategy of each Fund and knowledge gained from meetings with management, which were held on at least a quarterly basis. In addition, the Trustees reviewed the available

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Board Approval of the Advisory Agreement, continued

resources and key personnel of CWAM and its affiliates, especially those providing investment management services to the Funds. The Trustees also considered other services provided to the Funds by CWAM and its affiliates, including: managing the execution of portfolio transactions and selecting broker-dealers for those transactions; monitoring adherence to the Funds' investment restrictions; producing shareholder reports; providing support services for the Board and committees of the Board; communicating with shareholders; serving as the Funds' administrator; and overseeing the activities of the Funds' other service providers, including monitoring for compliance with various policies and procedures as well as applicable securities laws and regulations.

The Trustees concluded that the nature, quality and extent of the services provided by CWAM and its affiliates to each Fund under the Advisory Agreement were appropriate for the Funds and that the Funds were likely to benefit from the continued provision of those services by CWAM. They also concluded that CWAM currently had sufficient personnel, with appropriate education and experience, to serve the Funds effectively, and that the firm had demonstrated its continuing ability to attract and retain well-qualified personnel. In addition, they took note of the quality of CWAM's compliance record.

Performance of the Funds. The Trustees received and considered detailed performance information at various meetings of the Board, the Committee and the Investment Performance Analysis Committee of the Board throughout the year. They reviewed information comparing each Fund's performance with that of its benchmark(s) and with the performance of comparable funds and peer groups as identified by Lipper Inc. (Lipper) and Morningstar, Inc. (Morningstar). The Trustees evaluated the performance of the Funds over various time periods, including over the one-, three- and five-year periods ending December 31, 2010. The Trustees also considered peer performance rankings based on a rolling five-year period.

The Trustees noted that the international Funds have delivered excellent results over the past five years, and have done so while exposing investors to less risk than competing funds, according to Morningstar. They considered that the domestic Funds have had mixed results. Columbia Acorn Fund has achieved good performance over the one- and three-year periods, and slightly underperformed its peers over the five-year period, ending December 31, 2010; the Fund had excellent results over longer periods. Columbia Acorn Select had better than average results measured against its peers over the three- and five-year periods ending December 31, 2010, but underperformed more recently. Columbia Acorn Select outperformed its benchmark for the five-year period but underperformed over the one- and three-year periods ending December 31, 2010. Columbia Acorn USA fell behind its benchmark and peer group medians over the one-, three- and five-year periods ending December 31, 2010, and Columbia Thermostat Fund outperformed its benchmark (an equally weighted custom composite of the Fund's primary equity and debt indexes) over the one-, three- and five- year periods ending December 31, 2010, and enjoyed strong rankings from Morningstar over each of these periods. The Trustees noted that the Investment Performance Analysis Committee of the Board concluded that Fund performance was generally satisfactory, except that Columbia Acorn USA's performance had slipped below the Lipper and Morningstar medians during the past year. The Trustees considered that CWAM had taken and was taking a number of corrective steps with respect to Columbia Acorn USA's underperformance and that the Investment Performance Analysis Committee of the Board was monitoring the Fund's performance.

The Trustees concluded that, although past performance is not necessarily indicative of future results, the strong overall longer-term performance record of the Funds was an important factor in their evaluation of the quality of services provided by CWAM under the Advisory Agreement for each Fund.

Costs of Services and Profits Realized by CWAM. At various Committee and Board meetings, the Trustees examined detailed information on the fees and expenses of each Fund in comparison to information for comparable funds provided by Lipper and Morningstar. The Trustees reviewed data from Lipper and Morningstar and noted that in general the Funds' total net operating expenses were below their median peer group rankings, with each Fund having lower total net operating expenses than its Lipper peer group median and only Columbia Acorn USA having total net operating expenses above its Morningstar peer group median. As noted in the Fee Evaluation, the actual advisory fees paid by Columbia Acorn Select and Columbia Acorn USA were higher than the median advisory fee of the Funds' Lipper and Morningstar peer groups and the actual advisory fee paid by Columbia Acorn International Select was higher than the median advisory fee of the Fund's Lipper peer group, but not of its Morningstar peer group. The actual advisory fees paid by Columbia Acorn Fund, Columbia Acorn International and Columbia Thermostat Fund were lower than the median advisory fee of the Funds' Morningstar and Lipper peer groups.

The Trustees also considered that Ameriprise represented and agreed that advisory fees would not be raised for the two years following the close of its acquisition of CWAM (May 1, 2010) pursuant to Section 15(f) of the 1940 Act.

The Trustees also reviewed the advisory fee rates charged by CWAM for managing other investment companies (including the Columbia Wanger Funds), sub-advised funds and other institutional separate accounts, as detailed in the Fee Evaluation. The Trustees noted that the Funds' advisory fees were generally comparable to the Columbia Wanger Funds' advisory fees at

104

the same asset levels. The Trustees also examined CWAM's institutional separate account fees for various investment strategies; in some cases those fees were higher than the advisory fees charged to the Funds, and in a few instances the fees were lower. The Trustees noted that CWAM performs significant additional services for the Funds that it does not provide to sub-advised funds or non-mutual fund clients, including administrative services, oversight of the Funds' other service providers, Trustee support, regulatory compliance and numerous other services, and that, in servicing the Funds, CWAM assumes many legal risks that it does not assume in servicing many of its non-fund clients.

The Trustees concluded that the rates of advisory fees payable to CWAM were reasonable in relation to the nature and quality of the services to be provided. The Trustees also concluded that the Funds' overall expense ratios were reasonable, considering the quality of the services provided by CWAM and its affiliates and the investment performance of the Funds.

The Trustees reviewed the analysis of the historic profitability of CWAM in serving as each Fund's investment adviser and of CWAM and its affiliates in their relationships with each Fund. The Committee and Trustees met on several occasions with representatives from Ameriprise to discuss its methodologies for calculating profitability and allocating costs. They considered that Ameriprise calculated profitability and allocated costs on a contract-by-contract and fund-by-fund basis. The Trustees also considered the methodology used by CWAM and Ameriprise in determining compensation payable to portfolio managers and the competitive market for investment management talent. The Trustees were also provided with profitability information from Lipper and Strategic Insight, which compared CWAM's profitability to other similar investment advisers in the mutual fund industry. The Trustees concluded that CWAM's and its affiliates' profits were within a reasonable range of those of competitors with similar business models. The Trustees discussed, however, that profitability comparisons among fund managers may not always be meaningful due to the lack of consistency in data, small number of publicly-owned managers, and the fact that profitability of any investment manager is affected by numerous factors, including its particular organizational structure, the types of funds and other accounts managed, other lines of business, expense allocation methodology, capital structure and cost of capital.

Economies of Scale. At various Committee and Board meetings and other informal meetings, the Trustees considered information about the extent to which CWAM realizes economies of scale in connection with an increase in Fund assets. The Trustees also discussed the potential for Fund sales growth. The Trustees noted that the advisory fee schedule for each Fund, other than Columbia Thermostat Fund, which has relatively modest assets, includes breakpoints in the rate of fees at various asset levels. The Trustees concluded that the fee structure of each Fund was reflective of a sharing between CWAM and the Funds of economies of scale.

Other Benefits to CWAM. The Trustees also reviewed benefits that accrue to CWAM and its affiliates from their relationships with the Funds, as outlined in the Fee Evaluation. They noted that the Funds' transfer agency services are performed by Columbia Management Investment Services Corp., an affiliate of Ameriprise, which receives compensation from the Funds for its services provided. They considered that an affiliate of Ameriprise, Columbia Management Investment Distributors, Inc. (CMID), serves as the Funds' distributor under a distribution agreement, and that it receives fees under the Trust's Rule 12b-1 Plan, most of which CMID paid to broker-dealers. In addition, Columbia Management provides sub-administration services to the Funds. The Committee received information regarding the profitability of each Fund agreement with CWAM affiliates. The Committee and the Board also reviewed information about and discussed the capabilities of each affiliated entity in performing its duties.

The Trustees considered other ways that the Funds and CWAM may potentially benefit from their relationship with each other. For example, the Trustees considered CWAM's use of commissions paid by each Fund on its portfolio brokerage transactions to obtain research products and services benefiting the Funds and/or other clients of CWAM. The Committee reviewed CWAM's annual "soft dollar" report and met with representatives from CWAM to review CWAM's soft dollar spending. The Committee also considered that the Compliance Committee of the Board regularly reviewed third-party prepared reports that evaluated the quality of CWAM's execution of the Funds' portfolio transactions. The Trustees determined that CWAM's use of the Funds' "soft" commission dollars to obtain research products and services was consistent with current regulatory requirements and guidance. They also concluded that CWAM benefits from the receipt of proprietary research products and services acquired through commissions paid on portfolio transactions of the Funds, and that the Funds benefit from CWAM's receipt of those products and services as well as research products and services acquired through commissions paid by other clients of CWAM.

After full consideration of the above factors, as well as other factors that were instructive in evaluating the Advisory Agreement, the Trustees, including the Independent Trustees, unanimously concluded that the continuation of the Advisory Agreement was in the best interest of each Fund. On June 8, 2011, the Trustees approved continuation of the Advisory Agreement through July 31, 2012.

105

Columbia Acorn Family of Funds

Second Quarter Class A, B, C and I Share Information (Unaudited)

Minimum Initial Investment in all Funds	$2,000 for most Investors $1,000 for an IRA
Minimum Subsequent Investment in all Funds	$100
Exchange Fee	None

Columbia Acorn Fund	Class A			Class B*			Class C			Class I**
Management Fees		0.64	%		0.64	%		0.64	%		0.64	%
Distribution and Service (12b-1) Fees		0.25	%		0.75	%		1.00	%		0.00	%
Other Expenses		0.16	%		0.36	%		0.19	%		0.07	%
Net Expense Ratio		1.05	%		1.75	%		1.83	%		0.71	%
Columbia Acorn International	Class A			Class B*			Class C			Class I**
Management Fees		0.76	%		0.76	%		0.76	%		0.76	%
Distribution and Service (12b-1) Fees		0.25	%		0.75	%		1.00	%		0.00	%
Other Expenses		0.28	%		0.45	%		0.30	%		0.14	%
Net Expense Ratio		1.29	%		1.96	%		2.06	%		0.90	%
Columbia Acorn USA	Class A			Class B*			Class C			Class I**
Management Fees		0.86	%		0.86	%		0.86	%		0.86	%
Distribution and Service (12b-1) Fees		0.25	%		0.75	%		1.00	%		0.00	%
Other Expenses		0.17	%		0.42	%		0.19	%		0.08	%
Net Expense Ratio		1.28	%		2.03	%		2.05	%		0.94	%
Columbia Acorn International Select	Class A			Class B*			Class C			Class I**
Management Fees		0.94	%		0.94	%		0.94	%		0.94	%
Distribution and Service (12b-1) Fees		0.25	%		0.75	%		1.00	%		0.00	%
Other Expenses		0.33	%		0.51	%		0.39	%		0.06	%
Net Expense Ratio		1.52	%		2.20	%		2.33	%		1.00	%
Columbia Acorn Select	Class A			Class B*			Class C			Class I**
Management Fees		0.81	%		0.81	%		0.81	%		0.81	%
Distribution and Service (12b-1) Fees		0.25	%		0.75	%		1.00	%		0.00	%
Other Expenses		0.20	%		0.37	%		0.25	%		0.10	%
Net Expense Ratio		1.26	%		1.93	%		2.06	%		0.91	%
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 six months ended June 30, 2011. Some share classes of Columbia Acorn Select and Columbia Acorn International Select include the effect of the voluntary undertaking by Columbia Wanger Asset Management, LLC (CWAM) to waive fees and/or reimburse the Funds for any 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, in excess of the annual rate of the Funds as follows:

Fund	Class A			Class B			Class C			Class I
Columbia Acorn International Select		1.70	%		2.20	%		2.45	%		1.30	%
Columbia Acorn Select		1.60	%		2.10	%		2.35	%		1.25	%

    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 investments 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 waiver/reimbursement arrangement is contractual through April 30, 2012. There is no guarantee that this arrangement will continue thereafter.

  *  The Funds no longer offer Class B shares (other than through dividend reinvestment).

  **  Class I shares were initially offered by the Funds on September 27, 2010.

  ***  Does not include estimated fees and expenses of 0.65% incurred by the Fund from the underlying portfolio funds in which it invests.

106

Columbia Acorn Family of Funds

Trustees

Laura M. Born

Chair of the Board

Steven N. Kaplan

Vice Chair of the Board

Michelle L. Collins

Maureen M. Culhane

Margaret M. Eisen

John C. Heaton

Charles P. McQuaid

Allan B. Muchin

David J. Rudis

David B. Small

Ralph Wanger (Trustee Emeritus)

Officers

Charles P. McQuaid

President

Ben Andrews

Vice President

Robert A. Chalupnik

Vice President

Michael G. Clarke

Assistant Treasurer

Joseph F. DiMaria

Assistant Treasurer

P. Zachary Egan

Vice President

John M. Kunka

Assistant Treasurer

Joseph C. LaPalm

Vice President

Bruce H. Lauer

Vice President, Secretary and Treasurer

Louis J. Mendes III

Vice President

Robert A. Mohn

Vice President

Christopher J. Olson

Vice President

Christopher O. Petersen

Assistant Secretary

Scott R. Plummer

Assistant Secretary

Linda K. Roth-Wiszowaty

Assistant Secretary

Robert P. Scales

Chief Compliance Officer, Chief Legal Officer,
Senior Vice President and General Counsel

Investment Adviser

Columbia Wanger Asset Management, LLC
227 West Monroe Street, Suite 3000
Chicago, Illinois 60606

1-800-922-6769

Distributor

Columbia Management Investment Distributors, Inc.
225 Franklin Street
Boston, Massachusetts 02110

Transfer Agent, Dividend Disbursing Agent

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

1-800-345-6611

Legal Counsel to the Funds

Perkins Coie 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, is available from the SEC's website. Information regarding how the Funds voted proxies relating to portfolio securities is also available at www.columbiamanagement.com under "About Us." From there, click on "Disclosures."

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.

Investors should consider the investment objectives, risks, charges and expenses of a mutual fund carefully before investing. For a free prospectus, which contains this and other important information about the funds, visit www.columbiamanagement.com. Read the prospectus carefully before investing.

Columbia Acorn Funds are distributed by Columbia Management Investment Distributors, Inc., member FINRA and managed by Columbia Wanger Asset Management, LLC.

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

www.columbiamanagement.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.

Columbia Management^®

Columbia Acorn Family of Funds
Class A, B, C and I Shares

Second Quarter Report, June 30, 2011

For More Information

You'll find more information about the Columbia Acorn Family of 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 Investment Services Corp.
P.O. Box 8081
Boston, MA 02266-8081

By Telephone: 800.345.6611

Online: www.columbiamanagement.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, LLC, 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 is a series, is 811-01829.

© 2011 Columbia Management Investment Advisers, LLC. All rights reserved.

225 Franklin Street, Boston, MA 02110

800.345.6611 www.columbiamanagement.com

C-1454 C (8/11) 123272

Item 2. Code of Ethics.

Not applicable for semiannual reports.

Item 3. Audit Committee Financial Expert.

Not applicable for semiannual reports.

Item 4. Principal Accountant Fees and Services.

Not applicable for semiannual reports.

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 were no material changes to the procedures by which shareholders may recommend nominees to the registrant’s board of directors.

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 material 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: Not applicable for semiannual reports.

(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	August 19, 2011

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	August 19, 2011
By (Signature and Title)	/s/ Bruce H. Lauer
	Bruce H. Lauer, Treasurer
Date	August 19, 2011

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: August 19, 2011	/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: August 19, 2011	/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 June 30, 2011, 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: August 19, 2011	/s/ Charles P. McQuaid
	Charles P. McQuaid, President
Date: August 19, 2011	/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.