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)
One Financial Center, Boston, Massachusetts					02111
(Address of principal executive offices)					(Zip code)
James R. Bordewick, Jr., Esq. Columbia Management Advisors, LLC One Financial Center Boston, MA 02111
(Name and address of agent for service)
Registrant’s telephone number, including area code:				1-617-426-3750
Date of fiscal year end:	December 31, 2007
Date of reporting period:		June 30, 2007

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.

2Q

Columbia Acorn
Family of Funds

Class Z Shares

Semiannual Report

June 30, 2007

n  Columbia^TM   Acorn® Fund

n  Columbia^TM Acorn International®

n  Columbia^TM Acorn USA®

n  Columbia^TM Acorn International Select^SM

n  Columbia^TM Acorn Select^SM

n  Columbia^TM Thermostat Fund^SM

Managed by Columbia Wanger Asset Management, L.P.

NOT FDIC INSURED

NOT BANK ISSUED

May Lose Value

No Bank Guarantee

Descriptions of indexes included in this report:

•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.

•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^TM 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.

•S&P/Citigroup EMI Global ex-US is an unmanaged index consisting of the bottom 20% of institutionally investable capital of developed and emerging countries, outside the United States.

•S&P/Citigroup Global ex-US Cap Range $500mm-$5bn 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.

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

•S&P/Citigroup World ex-US Cap Range $2–10B is a subset of the broad market selected by the index sponsor representing the mid-cap developed market excluding the United States.

•Lipper Indexes include the largest funds tracked by Lipper, Inc. in the named category. Lipper Mid-Cap Growth Index, 30 mid-cap growth funds; Lipper Mid-Cap Core Funds Index, 30 mid-cap core funds; Lipper International Funds Index, 30 largest non-U .S. funds, not including non-U.S. small-cap funds; Lipper International Small-Cap Funds Index, 10 largest non-U.S. funds investing in small-cap companies, including Columbia Acorn International; Lipper Small-Cap Core Funds Index, 30 largest small-cap core funds, including Columbia Acorn Fund. Lipper Flexible Portfolio Funds Index is an equal dollarweighted index of the 30 largest mutual funds within the Flexible Portfolio fund classification, as defined by Lipper.

•Lehman Brothers U.S. Credit Intermediate Bond Index is the intermediate component of the U.S. Credit Index. The U.S. Credit Index includes publicly issued U.S. corporate and foreign debentures and secured notes that meet specified maturity, liquidity, and quality requirements.

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 "Squirrel Chatter II" and "In a Nutshell" commentary 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 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. References to specific company securities should not be construed as a recommendation or investment advice.

Columbia Acorn Family of Funds

Table of Contents

Performance At A Glance	2
Squirrel Chatter II: Buyout Boom	3
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	35
Statement of Investments	37
Portfolio Diversification	43
Columbia Acorn USA
In a Nutshell	14
At a Glance	15
Major Portfolio Changes	44
Statement of Investments	45

Columbia Acorn International Select
In a Nutshell	16
At a Glance	17
Major Portfolio Changes	51
Statement of Investments	52
Portfolio Diversification	55
Columbia Acorn Select
In a Nutshell	18
At a Glance	19
Major Portfolio Changes	56
Statement of Investments	57
Columbia Thermostat Fund
In a Nutshell	20
At a Glance	21
Statement of Investments	60
Columbia Acorn Family of Funds
Statements of Assets and Liabilities	62
Statements of Operations	63
Statements of Changes in Net Assets	64
Financial Highlights	68
Notes to Financial Statements	71
Management Fee Evaluation of the Senior Officer	78
Columbia Acorn Family of Funds Information	83

2007 Mid-Year Distributions

The following table lists the Funds' mid-year distributions. The record date was June 4, 2007. The ex-dividend date was June 5, 2007 and the payable date was June 6, 2007.

	Short-term Capital Gains		Long-term Capital Gains		Ordinary Income		Reinvestment Price
Columbia Acorn Fund	$	0.0462	$	0.3404		None	$	33.25
Columbia Acorn International		None	$	0.2470	$	0.1207	$	45.47
Columbia Acorn USA		None	$	0.2797		None	$	31.80
Columbia Acorn International Select		None		None	$	0.1487	$	30.90
Columbia Acorn Select	$	0.0898	$	0.0978		None	$	31.25
Columbia Thermostat Fund	$	0.0207	$	0.2751	$	0.0633	$	12.86

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Columbia Acorn Family of Funds

Performance At A Glance Class Z Average Annual Total Returns through 6/30/07

	NAV on 6/30/07		2nd quarter*			Year to date*			1 year			3 years			5 years			10 years			Life of Fund
Columbia Acorn Fund (ACRNX) (6/10/70)	$	32.76		6.70	%		11.55	%		20.66	%		17.20	%		18.09	%		15.24	%		16.41	%
Russell 2500				4.94	%		8.67	%		18.74	%		14.97	%		15.30	%		11.00	%		NA
S&P 500				6.28	%		6.96	%		20.59	%		11.68	%		10.71	%		7.13	%		12.02	%
Lipper Small-Cap Core Funds Index				6.21	%		9.54	%		17.17	%		13.74	%		13.79	%		10.22	%		NA
Lipper Mid-Cap Core Funds Index				6.06	%		11.09	%		20.82	%		14.71	%		14.16	%		10.80	%		NA
Columbia Acorn International (ACINX) (9/23/92)	$	45.82		8.61	%		14.59	%		34.91	%		30.75	%		24.42	%		13.80	%		15.06	%
S&P/Citigroup EMI Global ex-US				7.37	%		14.85	%		35.90	%		29.34	%		26.03	%		11.50	%		11.21	%
S&P/Citigroup Global ex-US Cap Range $500mm-$5bn				8.02	%		15.47	%		35.50	%		29.32	%		26.22	%		11.86	%		11.73	%
MSCI EAFE Index				6.40	%		10.74	%		27.00	%		22.24	%		17.73	%		7.66	%		9.35	%
Lipper Int'l Small-Cap Funds Index				7.57	%		14.85	%		33.39	%		28.48	%		25.78	%		14.13	%		NA
Columbia Acorn USA (AUSAX) (9/4/96)	$	31.11		5.81	%		9.50	%		16.03	%		13.73	%		15.19	%		12.22	%		14.23	%
Russell 2000				4.42	%		6.45	%		16.43	%		13.45	%		13.88	%		9.06	%		10.24	%
Lipper Small-Cap Core Funds Index				6.21	%		9.54	%		17.17	%		13.74	%		13.79	%		10.22	%		11.24	%
S&P 500				6.28	%		6.96	%		20.59	%		11.68	%		10.71	%		7.13	%		9.73	%
Columbia Acorn Int'l Select (ACFFX) (11/23/98)	$	31.12		7.38	%		11.80	%		35.02	%		26.76	%		21.96	%		NA			14.69	%
S&P/Citigroup World ex-US Cap Range $2-10B				6.08	%		12.04	%		29.92	%		26.26	%		22.67	%		NA			13.52	%
MSCI EAFE Index				6.40	%		10.74	%		27.00	%		22.24	%		17.73	%		NA			8.29	%
Lipper International Funds Index				7.49	%		11.48	%		28.40	%		22.84	%		17.55	%		NA			9.51	%
Columbia Acorn Select (ACTWX) (11/23/98)	$	30.86		9.12	%		16.76	%		32.54	%		19.66	%		18.46	%		NA			16.43	%
S&P MidCap 400				5.84	%		11.98	%		18.51	%		15.15	%		14.17	%		NA			12.69	%
Lipper Mid-Cap Growth Index				9.51	%		14.71	%		21.98	%		14.76	%		13.28	%		NA			8.51	%
S&P 500				6.28	%		6.96	%		20.59	%		11.68	%		10.71	%		NA			4.67	%
Columbia Thermostat Fund (COTZX) (9/25/02)†	$	12.77		2.07	%		4.43	%		12.88	%		9.07	%		NA			NA			11.26	%
S&P 500				6.28	%		6.96	%		20.59	%		11.68	%		NA			NA			15.68	%
Lehman Brothers U.S. Credit Intermediate Bond Index				-0.40	%		1.28	%		6.34	%		3.79	%		NA			NA			4.46	%
Lipper Flexible Portfolio Funds Index				4.96	%		6.79	%		16.83	%		11.10	%		NA			NA			13.46	%

*Not annualized.

Performance data quoted represents past performance and current performance may be lower or higher. Past performance is no guarantee of future results. The investment return and principal value of an investment in a Fund will fluctuate so that Fund shares, when redeemed, may be worth more or less than their original cost. Please visit columbiafunds.com for daily and most recent month-end updates. Net asset value (NAV) returns do not include sales charges or contingent deferred sales charges (CDSC). Class Z shares are sold only at NAV with no Rule 12b-1 fee. Class Z shares have limited eligibility and the investment minimum requirement may vary. 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.

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

Annual operating expense ratios are as stated in each Fund prospectus that is current as of the date of this report and differences in expense ratios disclosed elsewhere in this report may result from including fee waivers and reimbursements as well as different time periods used in calculating the ratios. Columbia Acorn Fund Class Z: 0.75%. Columbia Acorn International Class Z: 0.94%. Columbia Acorn USA Class Z: 1.01%. Columbia Acorn International Select Class Z: 1.28%. Columbia Acorn Select Class Z: 0.98%. Columbia Thermostat Fund has a contractual expense waiver or reimbursement that expires April 30, 2008. 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 1.10% and 0.94%, respectively. Absent the waiver or reimbursement, performance results may be lower.

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

All indexes are unmanaged and returns include reinvested distributions. It is not possible to invest directly in an index. For index definitions, see the inside front cover of this report.

2

Squirrel Chatter II: Buyout Boom

In last year's annual report, we mentioned that 26 Columbia Acorn Fund stocks were subject to takeover bids during the year. Takeovers certainly helped performance and we were pleased that buyers validated our fundamental research process by finding lots of our companies to be attractive.

In the first half of 2007, the buyout boom continued to accelerate. In just six months, 27 Columbia Acorn Fund stocks announced takeovers, beating the Fund's full year 2006 record. Columbia Acorn USA had 15 takeover stocks in common with Columbia Acorn Fund and one additional buyout not owned by Columbia Acorn Fund. Columbia Acorn International had three takeovers that overlapped with Columbia Acorn Fund and another that did not. Columbia Acorn Select and Columbia Acorn International Select had one takeover each; both were also held by Columbia Acorn Fund.

Generally, buyouts come in two basic flavors: strategic and financial. Strategic buyouts are often done by similar companies that want to pursue synergies, such as cost savings or enhanced products, production, distribution or pricing. Strategic buyers are usually other public companies and sometimes use their stock to pay for all or part of the acquisition. After some stock deals, we've kept the acquiring company's stock as a long-term investment.

Financial buyouts have historically been executed by private equity partnerships with private equity firms as general partners and other entities, such as pension funds and endowments, as limited partners. Financial partnerships usually borrow 70% to 85% of the acquisition price in order to enhance returns and minimize taxes on the acquired business.¹ Company management sometimes like to sell to private partners, as (1) they often get stock in the privatized company to stay and manage the business, and (2) they no longer have to deal with pesky securities analysts.

Our first half 2007 buyout announcements were a mixed lot. About 55% were strategic and 45% financial. The takeover terms have ranged from excellent to disappointing, though none so far this year have been "takeunders," at below last trade prices. We've had offers for big positions and small ones, and for long-standing holdings and newer ideas. Following are summaries of the takeover announcements made in the first half of 2007:

Takeover Log

January 8: United Surgical Partners, an operator of outpatient surgical centers, agreed to sell to a group led by Welsh, Carson, Anderson & Stowe, for $31.05 per share. Although we believed the valuation was fair based on reported results, we thought fundamentals would improve and the stock would have had high returns over the long run.

January 10: Alliance Atlantis Communications announced it was selling to a partnership including Goldman Sachs and CanWest Global Communications for C$53.² We first bought Alliance Atlantis in 2003, when it became focused on its more successful areas, the popular CSI television series and cable TV channels in Canada. Columbia Acorn Fund sold much of its position after the announcement but our remaining holding is up 150% from its cost.

February 5: Hanover Compressor agreed to merge with Universal Compression Holdings, a competitor, in a deal for stock. Both companies rent compressors to the natural gas industry, and the companies believe the combination will result in cost savings and larger service areas. We agree and Columbia Acorn USA as of press time kept its position in Hanover.

February 8: Edgars Consolidated Stores, a South African retailer, said it would sell to Bain Capital. Edgars' offer was 50% over its price prior to deal news back in October 2006, but was not at a premium to similar public companies. We owned Edgars in Columbia Acorn Fund and Columbia Acorn International, correctly believing that new management would enable the company to benefit from an improving regional economy. While the buyout price was somewhat disappointing, both funds booked at least a double in under three years.

February 12: A twin-deal day. First, UrAsia Energy, a Canadian uranium miner with operations in Kazakhstan, announced a merger for sxr Uranium One stock. Uranium One is a Canadian uranium miner with operations primarily in South Africa. This was Columbia Acorn Select's only deal. With Columbia Acorn Fund and Columbia Acorn International also owning the stock, it was our largest dollar deal, exceeding

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$250 million across the three funds. We continue to like uranium mining economics and the funds now own Uranium One. Second, Witness Systems agreed to sell to Verint, a strategic buyer, for $27.50 per share, a price we considered to be fair.

February 14:TALX announced a sellout to Equifax for a cash and stock deal valued at $35.50, an 11% premium to TALX's last closing price. We were disappointed by the offer, though it was more than a 20% premium to our cost. While that was an excellent compound rate of return as we owned the stock for only several months, we'd rather hold stocks for much longer periods and potentially make more money.

February 19: Florida Rock agreed to merge with fellow aggregates company Vulcan Materials for cash and stock worth a stated $68 per share, a 45% premium to Florida's prior closing price. We like the business as barriers to entry are high—people don't want rock mines in their back yards—and transportation costs keep out remote competitors. Consequently, it was one of our larger holdings. We thought Florida's stock price had seemed irrationally depressed due to concerns about the housing industry and Vulcan noticed. As of June 30, both Columbia Acorn Fund and Columbia Acorn USA had more than a double in their investment in Florida Rock and Columbia Acorn Fund also started a position in Vulcan.

February 21: Central Parking announced a sale to private equity consortium KCPC Holdings for $22.53 per share in cash. Central Parking had reportedly turned down offers that were $15 to $16 in the middle of 2006, but somehow real estate values have surged since then. We consider the new price to be fair.

March 2: Dendrite International, a provider of software and services to pharmaceutical marketing departments, reported that it would sell out to Cedegim, a French software company, for $16 in cash. We believed that Dendrite provided value to its customers, but we were disappointed by a lack of consistent growth. We think the deal was at a fair price given earnings volatility.

March 6: K&F Industries agreed to sell to Meggitt PLC, a fellow producer of aircraft wheels and brakes, for $27 per share in cash. The price represented just a 10% premium to the prior day's close and appeared cheap compared to cash flow. The company did allow competing bids, but none emerged. We believe we bought the stock at the right time in Columbia Acorn Fund and Columbia Acorn USA, as it returned over 60% in the 15 months that we held it.

March 15: WebEx announced a sellout to Cisco for $57 per share in cash, a 23% premium to its March 14 closing price. This was one of our quickest and smallest deals, as we had started buying the stock for Columbia Acorn Fund in January. Like the TALX deal, we got a fine rate of return, but we would have rather made potentially more dollars over a longer period of time.

March 19: ServiceMaster entered into a deal to sell to Clayton, Dubilier & Rice, a private equity firm, for $15.625 per share in cash. ServiceMaster was a great stock until about 1998 but it subsequently struggled. We bought it last year for Columbia Acorn Fund, thinking that new management could restructure and grow the business. Instead, the company decided to sell out at a relatively modest premium. Once again our rate of return was fine but we did not earn large dollars over the longer term.

March 23: Kronos agreed to sell to a group led by Hellman & Friedman for $55 per share in cash. We first bought Kronos over 10 years ago as a downstream-from-technology investment; the company substituted semiconductors for electromechanical devices in employee timeclocks. As years progressed, Kronos expanded its product portfolio with software offerings including shift scheduling, human resource management and recruiting. Earnings growth was erratic due to economic and product cycles and that provided some opportunities for long-term investors. We view the deal price as reasonable. Kronos was our second largest deal this year, as Columbia Acorn Fund and Columbia Acorn USA cashed out for over $180 million.

April 19: Van Houtte, a Canadian gourmet coffee equipment and services company, said it had a non-binding offer from an undisclosed buyer of C$25 per share, a 1% premium to its average price over the prior 30 days. The stock spiked up from C$17 in January, after the company said it was reviewing strategic options. In May the company entered into a definitive agreement and identified the buyer as Littlejohn & Co, a private equity firm. While we were disappointed with the sale price, Columbia Acorn International booked about a 40% profit in 14 months.

April 24: Highland Hospitality said it would sell out to JER Partners, a private equity firm focused on real estate, for $19.50 per share. Though we had cut our real estate holdings several years ago, we believed that the hotel business had favorable supply/demand characteristics and that Highland added value by acquiring and improving properties. We began buying the stock in December 2003. Upon the close of the deal in late July, Columbia Acorn Fund and

4

Columbia Acorn USA realized over 70% gains from its average cost, in addition to dividends previously booked.

May 7: Armor Holdings, a military vehicle and armor business, announced a sellout to BAE Systems, a UK defense conglomerate, for $88 per share in cash. We started buying the stock for Columbia Acorn Fund in December 2006, believing that the demand for military armor would grow over the long term and that Armor was well positioned. We thought the takeout price was fair, and when the deal closed following the period end, the Fund realized a 61% gain.

May 14: Viasys Healthcare agreed to sell out to Cardinal Health for $42.75 per share in cash, a 36% premium to its last closing price. We thought that price was a fair multiple on earnings and cash flow, and we subsequently learned that Viasys pursued a lengthy bidding process in order to obtain the highest price. We applaud management and directors for that effort. Upon the deal's close in June, Columbia Acorn Fund realized a 130% gain and Columbia Acorn USA tripled its investment.

May 15: Agile Software, a company that produces programs to handle changes in product design, said it would sell out to Oracle for $8.10 per share. The price represented a 12% premium to the stock's last trade. We bought the stock a year earlier, correctly believing that sales would increase and profits would commence.

May 21: Cellular phone company Alltel announced a sale to private equity buyers TPG Capital and Goldman Sachs for $71.50 cash per share. Our Alltel shares were derived from a previous takeover, as a result of it buying Western Wireless, a rural cellphone company. We had expected Alltel to sell out and were relieved upon the announcement because we were leery of increasing competition. We sold our remaining positions shortly after the announcement, realizing over 400% gains over our original Western Wireless costs, in both Columbia Acorn Fund and Columbia Acorn USA.

Also on May 21, Cytyc, a dominant producer of consumable diagnostic and surgical products for women's health, agreed to sell out to Hologic for a combination of cash and stock. The merger appears to make sense for both companies as we believe the combined company can boost sales and reduce costs. We have owned Cytyc since early 2005 in Columbia Acorn Fund and, at quarter end, showed a 75% profit on our investment.

May 22: Crescent Real Estate Equities, which primarily owns office buildings, announced a sale to Morgan Stanley Real Estate, a private fund, for cash. The $22.80 price was just a 6% premium to the stock's prior close, which barely offsets dividends that were cancelled until the deal is expected to close in the third quarter. Furthermore, the price represented a 5% to 10% discount to what we then believed the company was worth.

May 30: Ceridian, a provider of payroll processing, other HR services, trucker transactions processing and gift cards, agreed to sell to Thomas H. Lee Partners and Fidelity National Financial for $36 cash per share. We believe that Ceridian's core HR business is a solid franchise undergoing internal improvement and its other businesses are gems. Governance, however, became somewhat like a soap opera as an activist hedge fund bought a 15% interest, agitated for strategic restructuring, and began negotiating with a division head, who then got fired. That is all a shame, as we think the $36 price undervalues the company's potential.

June 15: Penn National Gaming, a regional casino operator, said it would sell out to a private group, which includes management, Fortress Investment and Centerbridge Partners, for $67 per share in cash. The bid was a 31% premium to the prior day's stock price, and at what we considered to be a fair multiple of cash flow. With Penn's proposed sale later this year, and Kerzner International's and Station Casino's announced sellouts last year, there are expected to be few public small- and mid-cap casino companies remaining.

June 18: Footwear retailer Genesco gave itself the boot as a public company, agreeing to sell out to Finish Line, another footwear retailer, for $54.50 cash per share. In April and May, the board of Genesco had rejected lower offers from Foot Locker. We think the $54.50 price is fair and we applaud the board for holding out for that price.

June 20: Nuveen Investments said it would be acquired by a private group lead by Madison Dearborn Partners, for $65 per share in cash. We like the investment management business, and Columbia Acorn Fund started buying Nuveen in late 2004. Columbia Acorn Select later bought a position. Unfortunately, in early 2007 we trimmed Columbia Acorn Fund's holdings and sold out of Columbia Acorn Select's position due to valuation and fears that growth would slow. Columbia Acorn Fund will realize nearly a 100% gain on its remaining shares if the deal is executed under its announced terms.

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June 26: Stork, a Netherlands-based conglomerate, agreed to sell to private equity firm Candover Investments. The price, 47 Euros cash per share, represented a 12% premium to the stock's prior close. Stork has been harassed by activist shareholders demanding that it be split up, and the company sees the sale as a way to resolve the dispute. We believe the small premium does not reflect Stork's underlying value. We understand that a supermajority vote is needed to approve the buyout and we think the 47 Euro price may need to be increased for a transaction to occur. Columbia Acorn Fund, Columbia Acorn International and Columbia Acorn International Select owned the stock.

June 27: Chittenden, a New England bank, announced it would sell to People's United Financial, another company held by Columbia Acorn Fund and Columbia Acorn USA, for a combination of stock and cash. The banking industry in the United States has been consolidating for a long time, and Columbia Acorn Fund has benefited from a lot of bank sellouts. While we believe this sellout price is fair and Chittenden was certainly a profitable investment for Columbia Acorn Fund and Columbia Acorn USA, our funds' positions in People's United fell on the news somewhat more than their positions in Chittenden rose.

June 29: Another rural cellular phone company, Dobson Communications, announced it would sell. This deal is for cash and the buyer is AT&T, which operates nearby cellular systems that utilize the same technology as Dobson. Columbia Acorn Fund has owned cellphone franchises since the industry began in the 1980s and has benefited from numerous sellouts. Similar to the casino industry, few small- and mid-cap public cellular companies remain.

Trillion Dollar Question

Buyout booms tend to run in cycles. Typically, private equity is able to raise more equity capital after a few years of good returns, and is able to raise debt funding when interest rates for "junk" bonds are at relatively low premiums to quality bonds. Then buyout momentum accelerates. Increased private equity activity seems to spur more strategic acquisitions and buyout prices rise.

The dollar volume of private equity buyouts in the United States and Europe averaged around $30 billion a year from 2000 to 2002, and then ramped to an unprecedented level in 2006, around $384 billion!³ While the dollar amount of private buyouts in 2006 broke records, as a percentage of stock market valuation it was barely half of 1988's level. Private equity recently had about $250 billion of equity capital available for buyouts, and was continuing to raise a lot more.⁴ Adding debt to this equity suggests that private equity would be able to buy over a trillion dollars of assets. The trillion dollar question is whether lenders will continue to fund lots of buyouts at low interest rates.

Credit markets in the first half of 2007 were very loose relative to historical standards. While we think buyout prices were high, we believe they had not yet reached "bubble" levels. We do not think we have seen the marquee "big and dumb" deals, which would normally suggest the buyout boom is nearing an end.

However, credit market conditions changed considerably after the June 30 end of this report period. Home mortgage defaults kept growing, especially for sub-prime mortgages. Mortgage-backed security prices fell, triggering huge losses for some hedge funds and creating concerns about possible losses elsewhere. Credit markets tightened overall and premiums for "junk" bonds increased.

Previously announced financial buyout deals generally have gotten funded, at first with sweetened terms for bond financing and later by bank commitments rather than primarily by bonds. Banks appear to be honoring existing financing commitments but seem to be limiting additional obligations.

At press time, the debt market was chaotic. While several high quality corporations were able to issue new bonds, risky borrowers appear locked out. We don't know what will happen next. We believe that there is a reasonable chance that the mortgage-backed security problem will be contained and its casualties clearly defined, allowing the remainder of the credit markets to return to normal. Higher quality financial buyouts could then resume. We feel there is also a chance that credit markets will remain tight for a long time, severely limiting new buyouts.

We usually buy stocks in order to grow with them for a long time, not to participate in a buyout within a few

6

months. We recognize that buyout cycles come and go. We benefited from the buyout cycle and will likely continue to benefit from it should it resume, but we will not change our investment objectives, strategy, style or process.

Charles P. McQuaid

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

While some of the deals have closed, there can be no assurance that the remaining transactions discussed above will be consummated on the terms and conditions, or that the Funds will profit to the extent, described herein.

All holding gains mentioned are calculated based on tax lots of securities held at the time of publication and additional tax lots may have been previously sold at higher costs for some stocks.

¹  Data taken from a presentation given by Steven Kaplan, Neubauer Family Professor of Entrepreneurship and Finance, University of Chicago Graduate School of Business, to the Chicago Analyst Society on June 11, 2007. Steven is also a trustee of the Columbia Acorn Trust.

²  The "C" denotes Canadian dollars here and elsewhere in the essay.

³  "The Financing of Large Buyouts: An Empirical Analysis," a paper coauthored by Ulf Axelson, Tim Jenkinson, Per Stromberg and Michael Weisbach. Preliminary version dated April 3, 2007.

⁴  Ibid.

Fund weightings at June 30, 2007, in the holdings mentioned were as follows:

Alliance Atlantis Communication: Columbia Acorn Fund, 0.1%

Hanover Compressor: Columbia Acorn USA, 0.5%

Uranium One: Columbia Acorn International, 0.7%; Columbia Acorn Fund, 0.4%; Columbia Acorn Select, 6.2%

Florida Rock: Columbia Acorn USA, 0.8%; Columbia Acorn Fund, 0.6%

Vulcan Materials: Columbia Acorn Fund, 0.1%

ServiceMaster: Columbia Acorn Fund, 0.4%

Van Houtte: Columbia Acorn International, 0.4%

Highland Hospitality: Columbia Acorn Fund, 0.5%; Columbia Acorn USA, 0.4%

Armor Holdings: Columbia Acorn Fund, 0.3%

Agile Software: Columbia Acorn Fund, 0.1%; Columbia Acorn USA, 0.1%

Cytyc: Columbia Acorn Fund, 0.4%

Crescent Real Estate Equities: Columbia Acorn Fund, 0.1%

Ceridian: Columbia Acorn USA, 1.1%; Columbia Acorn Fund, 0.6%

Penn National Gaming: Columbia Acorn Fund, 0.5%

Genesco: Columbia Acorn USA, 0.3%; Columbia Acorn Fund, 0.2%

Nuveen Investments: Columbia Acorn Fund, 0.4%

Stork: Columbia Acorn International Select, 2.3%; Columbia Acorn International, 1.0%

Chittenden: Columbia Acorn USA, 0.4%; Columbia Acorn Fund, 0.2%

Dobson Communications: Columbia Acorn USA, 1.1%; Columbia Acorn Fund, 0.4%

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. A fund that maintains a relatively concentrated portfolio may be subject to greater risk than a fund that is more fully diversified.

Past performance is no guarantee of future results.

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, Rule 12b-1 fees and other Fund expenses. The information on this page 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 $1,000.00, 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 yo u paid during the reporting period. See the "Compare with other funds" information for details on using the hypothetical data.

January 1, 2007 – June 30, 2007

	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		1,115.49		1,021.17		3.83		3.66		0.73
Columbia Acorn International		1,000.00		1,000.00		1,145.89		1,020.33		4.79		4.51		0.90
Columbia Acorn USA		1,000.00		1,000.00		1,095.01		1,019.98		5.04		4.86		0.97
Columbia Acorn International Select		1,000.00		1,000.00		1,118.02		1,018.89		6.25		5.96		1.19
Columbia Acorn Select		1,000.00		1,000.00		1,167.61		1,020.23		4.94		4.61		0.92
Columbia Thermostat Fund		1,000.00		1,000.00		1,043.49		1,023.55		1.27		1.25		0.25

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

Had the Investment adviser or any of its affiliates not waived or reimbursed a portion of expenses, account value at the end of the period would have been reduced.

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 fees or exchange fees. Therefore, the hypothetical examples provided may not help you determine the relative total costs of owning different funds. If these transaction costs were included, your costs would have been higher.

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

*For the six months ended June 30, 2007.

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, redemption fees or exchange fees.

8

Estimating your actual expenses

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

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

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

1.  Divide your ending account balance by $1,000.00. 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.

9

Columbia Acorn Fund

In a Nutshell

Charles P. McQuaid

Lead Portfolio Manager

Robert A. Mohn

Co-Portfolio Manager

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

Fund's Positions

in Mentioned Holdings

as of 6/30/07

ITT Educational Services	1.1	%
Eaton Vance	1.1	%
Fugro	1.1	%
People's United	0.8	%
Florida Rock	0.6	%
Penn National Gaming	0.5	%
Highland Hospitality	0.5	%
ESCO Technologies	0.4	%
Hong Kong Exchanges and Clearing	0.4	%
Housing Development Finance	0.4	%
Hexagon	0.4	%
Armor Holdings	0.3	%
Chittenden	0.2	%
Shuffle Master	0.2	%
Crescent Real Estate Equities	0.1	%

Columbia Acorn Fund rose 11.55% in the first half of 2007, nicely beating the 8.67% return of the small-cap Russell 2500 Index, and also pacing ahead of other benchmarks. The Fund rose 6.70% in the second quarter, moderately outperforming the Russell 2500's gain of 4.94%, and slightly outperforming other benchmarks.

Stock selection drove fine results, and the same three companies were our largest dollar winners for both the first half and the second quarter. ITT Educational Services jumped 77% in the half and 44% in the quarter on strong sales and profit margins. Eaton Vance appreciated 35% in the half and 24% in the quarter; its assets under management surged as the company created new closed-end funds. Netherlands-based Fugro rounded out the winners' circle, up 35% and 27% respectively, on strong demand for energy industry offshore services.

Sellouts also boosted performance. In the first half, Kronos was the Fund's largest dollar winner as a result of takeovers, clocking a 50% gain, while Armor Holdings and Florida Rock were the largest percentage winners, each up about 58%. In the second quarter, Penn National Gaming scored the Fund's largest takeover dollar jackpot and percentage gain, up 42%. There were 27 takeovers in the half, beating the 26 in all of 2006; they boosted performance by over 1.5%. We discuss these takeovers in "Squirrel Chatter II" beginning on Page 3 of this report.

The Fund had relatively low investments in industries that did not perform well. Real estate stocks within the Russell 2500 were down in the first half of 2007, after many stellar years. Columbia Acorn Fund's real estate investment was both relatively small and actually profitable, thanks to announced takeovers of Highland Hospitality and Crescent Real Estate Equities. In the second quarter, Russell 2500 bank and utility stocks also did poorly. The Fund had relatively small investments in both areas.

Columbia Acorn Fund's largest dollar loser in the first half was People's United, a Connecticut savings and loan company. It lost 16% in part due to its somewhat dilutive acquisition of another Fund bank holding, Chittenden, which rose 15%. Shuffle Master dropped 37% in the half due to poor earnings. ESCO Technologies declined 19% in the quarter on news that a major customer of its automatic meter readers was reconsidering its requirements.

Columbia Acorn Fund's international stocks resumed their outperformance in the quarter, and rose 14.56%, boosting their first half gain to 18.85%. In addition to Fugro, mentioned above, top winners for the quarter were Hong Kong Exchanges and Clearing, up 48% on regulatory changes which allow mainland Chinese to own stocks listed in Hong Kong. Housing Development Finance booked a 44% gain on India's prosperity and housing boom. Hexagon, a Swedish manufacturer of measurement equipment and polymers, gained 42% due to excellent earnings. At the end of the half, foreign stocks were 11.5% of Columbia Acorn Fund, up slightly from 11.3% last quarter but down from 13.7% year-to-year.

Small- and mid-cap stocks are often more volatile and less liquid than the stocks of larger companies. Small companies may have a shorter history of operations than larger companies and may have a less diversified product line, making them more susceptible to market pressure. 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 characteristics and holdings.

10

Columbia Acorn Fund (ACRNX)

At a Glance

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

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

through June 30, 2007

Inception 6/10/70	Year to date*			1 year			5 years			10 years
Returns before taxes		11.55	%		20.66	%		18.09	%		15.24	%
Returns after taxes on distributions		11.33			19.18			17.42			13.60
Returns after taxes on distributions and sale of fund shares		7.74			15.09			15.87			12.82
Russell 2500 (pretax)		8.67			18.74			15.30			11.00
S&P 500 (pretax)		6.96			20.59			10.71			7.13

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.

*Year to date data not annualized.

Columbia Acorn Fund Portfolio Diversification

as a % of net assets as of 6/30/07

Columbia Acorn Fund Top 10 Holdings

as a % of net assets as of 6/30/07

1.	Coach Designer & Retailer of Branded Leather Accessories	1.6	%
2.	Eaton Vance Specialty Mutual Funds	1.1	%
3.	ITT Educational Services Post-secondary Degree Programs	1.1	%
4.	Abercrombie & Fitch Teen Apparel Retailer	1.1	%
5.	Fugro (Netherlands) Oilfield Services	1.1	%
6.	Expeditors International of Washington International Freight Forwarder	1.1	%
7.	FMC Technologies Oil & Gas Well Head Manufacturer	1.1	%
8.	Chico's FAS Women's Specialty Retailer	1.0	%
9.	Genlyte Group Commercial Lighting Fixtures	1.0	%
10.	Ametek Aerospace/Industrial Instruments	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 $75,000 Investment in Columbia Acorn Fund (Class Z)

June 10, 1970 through June 30, 2007

This graph compares the results of $75,000 invested in Columbia Acorn Fund at inception on June 10, 1970 to the S&P 500 Stock Index and to an initial $238,325 investment in the Russell 2500 on the index's December 31, 1978 inception date. 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:
$21,231.3 million

*A $75,000 investment in Columbia Acorn Fund at inception appreciated to $238,325 on December 31, 1978, the inception date of the Russell 2500. For comparison with the Russell 2500, we assigned the index the same value as the Fund at index inception.

11

Columbia Acorn International

In a Nutshell

P. Zachary Egan

Co-Portfolio Manager

Louis J. Mendes III

Co-Portfolio Manager

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

Fund's Positions

in Mentioned Holdings

as of 6/30/07

Hong Kong Exchanges and Clearing	1.4	%
Hexagon	1.4	%
China Shipping Development	1.0	%
Singapore Exchange	0.8	%
Taewoong	0.6	%
Burckhardt Compression	0.6	%
Lenovo Group	0.5	%
Sung Kwang Bend	0.5	%

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

Columbia Acorn International ended the quarter up 8.61% vs. a 7.37% gain for the benchmark S&P/Citigroup EMI Global ex-US Index. Year to date, the Fund was up 14.59% vs. a 14.85% gain for the benchmark.

Returns varied considerably by region. Led by Korea and China, the Fund's Asia ex-Japan holdings posted a nearly 32% return on the back of positive earnings surprises and liquidity inflows to the region. Liberalization measures in China allowing local investment companies to invest overseas—with Hong Kong as the most likely initial recipient of these funds—boosted sentiment regarding China–focused companies. China Shipping Development, one of China's largest shipping companies, rose 54% in the quarter and year to date, in part due to its large valuation gap when compared to its domestic-listed shares. Lenovo Group, China's largest computer company, rose nearly 61% in the quarter and was up 45% for the half year on improved earnings and the continued attention towards high profile Chinese companies. The regional exchanges also continued to drive good returns, with Hong Kong Exchanges and Clearing and Singapore Exch ange both jumping 48% in the second quarter as trading volumes increased in what is largely a fixed cost base business. The Fund's top two performers were two niche Korean industrial companies, Sung Kwang Bend and Taewoong. These recent additions to the Fund rose 141% and 103% respectively, in the quarter. Gains were driven by the strong growth in global infrastructure and construction projects, particularly in the Middle East where Korean companies have a long track record in infrastructure development. For the half year, Sung Kwang Bend was up an impressive 285% and Taewoong reached a 104% gain. We applaud our analyst who covers this region, Jeannie Cheung, for ferreting out these ideas.

The Fund's holdings in Continental Europe and Canada also posted strong results, rising 12% and 17%, respectively, in the quarter. Our long-term strategy of investing in what we believe to be high-quality European industrial stocks continued to pay off. Burckhardt Compression, a Swiss supplier of gas compression pumps, and Hexagon, a Swedish manufacturer of measurement equipment and polymers and the Fund's second largest position at the outset of the quarter, both rose over 40% in the second quarter on continued strong demand for their highly specialized products.

Japanese stocks dominated the list of underperformers. Despite a reasonably strong domestic economy, flat wage growth has lead to lackluster domestic consumption as consumers save rather than spend. Moreover, Japanese savers, attracted by higher yields than they can receive at home, are increasingly investing overseas. This has contributed to yen weakness relative to world currencies, placing a further drag on performance.

The other regions of note were the poorly performing British and Irish markets. After posting strong returns in 2006, these markets have seen a strong pullback thus far in 2007 on concerns over higher interest rates, extended valuations and a deepening financial crisis. Since the beginning of 2007, we have significantly reduced our exposure to these markets, but still have been affected by the overall poor sentiment. As a region, the United Kingdom/Ireland was flat in the second quarter.

International investments involve greater potential risks, including less regulation, currency fluctuations, economic instability and political developments. Investments in small- and mid-cap companies may be subject to greater volatility and price fluctuations because they may be thinly traded and less liquid.

12

Columbia Acorn International (ACINX)

At a Glance

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

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

through June 30, 2007

Inception 9/23/92	Year to date*			1 year			5 years			10 years
Returns before taxes		14.59	%		34.91	%		24.42	%		13.80	%
Returns after taxes on distributions		14.39			33.01			23.81			12.67
Returns after taxes on distributions and sale of fund shares		9.60			24.79			21.68			11.82
S&P/Citigroup EMI Global ex-US (pretax)		14.85			35.90			26.03			11.50
S&P/Citigroup Global ex-US Cap Range $500mm-$5bn		15.47			35.50			26.22			11.86

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.

* Year to date data not annualized.

Columbia Acorn International Portfolio Diversification

as a % of net assets as of 6/30/07

Columbia Acorn International Top 10 Holdings

as a % of net assets as of 6/30/07

1.	Fugro (Netherlands) Oilfield Services	1.6	%
2.	Hong Kong Exchanges and Clearing (Hong Kong) Hong Kong Equity & Derivatives Market Operator	1.4	%
3.	Hexagon (Sweden) Measurement Equipment & Polymers	1.4	%
4.	SES Global (France) Satellite Broadcasting Services	1.2	%
5.	Housing Development Finance (India) Indian Mortgage Lender	1.2	%
6.	Atwood Oceanics (United States) Offshore Drilling Contractor	1.1	%
7.	Suzano (Brazil) Brazilian Pulp & Paper Producer	1.1	%
8.	ShawCor (Canada) Oil & Gas Pipeline Products	1.0	%
9.	Kuehne & Nagel (Switzerland) Freight Forwarding/Logistics	1.0	%
10.	China Shipping Development (China) China's Dominant Shipper for Oil & Coal	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 International (Class Z)

September 23, 1992 through June 30, 2007

This graph compares the results of $10,000 invested in Columbia Acorn International at inception on September 23, 1992 to the S&P/Citigroup EMI Global ex-US and the S&P/Citigroup Global ex-US Cap Range $500mm-$5bn Index. The indexes are unmanaged and returns for both the indexes 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:
$5,458.7 million

13

Columbia Acorn USA

In a Nutshell

Robert A. Mohn

Lead Portfolio Manager

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

Fund's Positions

in Mentioned Holdings

as of 6/30/07

ITT Educational Services	2.5	%
FMC Technologies	1.9	%
Atwood Oceanics	1.5	%
ESCO Technologies	1.4	%
Flir Systems	1.2	%
True Religion Apparel	1.1	%
Dobson Communications	1.1	%
II-VI	0.8	%
J. Crew Group	0.6	%
Nektar Therapeutics	0.3	%

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

Columbia Acorn USA gained 5.81% in the second quarter, outperforming the 4.42% increase of the Russell 2000 Index. The Fund also topped the index year to date through June 30, increasing 9.50% vs. the index's 6.45% gain. A continued underweight in financials contributed to the Fund's outperformance. A victim of deteriorating fundamentals and lingering concerns over credit losses, the financial sector fell 2% in the second quarter and was down more than 6% for the half year in the Russell 2000 Index. Columbia Acorn USA had a 9% weight in financial stocks at quarter end, less than half of the 21% weight in the Russell 2000.

Strong performance of consumer stocks also bolstered the Fund's relative performance. ITT Educational Services, a provider of post-secondary degree programs, was the Fund's leader in the consumer sector and overall. The stock was up 44% for the quarter and 77% year to date on strong student enrollment growth. True Religion Apparel, a maker of high-end denim clothing, gained 25% in the quarter and 33% for the six months on aggressive retail store opening plans. Apparel retailer J. Crew Group was up 35% in the quarter and 40% for the half year thanks to explosive earnings growth of 70% year-over-year.

Other winners included Flir Systems, a manufacturer of infrared cameras. The stock gained 30% in the quarter and was up 45% year to date on news of large contract wins with the U.S. Army. Dobson Communications, a rural cellular service provider, gained 29% in the quarter on speculation that the company would be bought out. On June 29, after the market closed on the last day of the quarter, Dobson did indeed announce they were being acquired by AT&T. For the semiannual period, the stock was up 28%. Atwood Oceanics and FMC Technologies increased due to healthy demand for deep-water drilling contractors (Atwood Oceanics) and oil and gas well head manufacturers (FMC Technologies). Atwood gained 17% in the quarter and was up 40% for the half year while FMC Technologies posted a 14% quarterly gain and 29% year-to-date return.

Laggards included ESCO Technologies, a maker of automated electric meter readers. The stock fell 19% in the quarter and was off 20% for the six months on news of possible changes in a large contract with a California utility. II-VI, a maker of laser components, fell 20% in the quarter due to operational difficulties. Year-to-date the company is showing less than a 3% loss.

Two biotech names also landed in the loser column. The Medicines Company, a maker of cardiovascular drugs, fell 23% in the quarter and was off 39% for the half year as an appeal to extend one of its major drug patents was denied. We sold the stock. Nektar Therapeutics, a provider of drug delivery technologies, fell 27% in the quarter and was off 38% for the six months as sales of the company's inhaleable insulin came in under expectations.

While certain sectors, such as housing, have been under a lot of pressure so far this year, we believe the overall economy remains remarkably healthy. We feel the market is continuing to offer plenty of investment opportunities for discriminating small-cap investors.

Risks include stock market fluctuations due to economic and business developments. Investments in small- and mid-cap companies may be subject to greater volatility and price fluctuations because they may be thinly traded and less liquid.

14

Columbia Acorn USA (AUSAX)

At a Glance

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

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

through June 30, 2007

Inception 9/4/96	Year to date*			1 year			5 years			10 years
Returns before taxes		9.50	%		16.03	%		15.19	%		12.22	%
Returns after taxes on distributions		9.36			15.58			14.89			11.50
Returns after taxes on distributions and sale of fund shares		6.37			10.98			13.34			10.57
Russell 2000 (pretax)		6.45			16.43			13.88			9.06

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.

*Year to date data not annualized.

Columbia Acorn USA Portfolio Diversification

as a % of net assets as of 6/30/07

Columbia Acorn USA Top 10 Holdings

as a % of net assets as of 6/30/07

1.	ITT Educational Services Post-secondary Degree Programs	2.5	%
2.	Genlyte Group Commercial Lighting Fixtures	2.2	%
3.	Crown Castle International Communications Towers	2.1	%
4.	FMC Technologies Oil & Gas Well Head Manufacturer	1.9	%
5.	Time Warner Telecom Fiber Optic Telephone/Data Services	1.8	%
6.	AmeriCredit Auto Lending	1.7	%
7.	Abercrombie & Fitch Teen Apparel Retailer	1.7	%
8.	Edwards Lifesciences Heart Valves	1.7	%
9.	Oxford Industries Branded & Private Label Apparel	1.7	%
10.	Tellabs Telecommunications Equipment	1.6	%

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

The Growth of a $75,000 Investment in Columbia Acorn USA (Class Z)

September 4, 1996 through June 30, 2007

This graph compares the results of $75,000 invested in Columbia Acorn USA at inception on September 4, 1996 to the Russell 2000 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:
$1,703.5 million

15

Columbia Acorn International Select

In a Nutshell

Christopher J. Olson

Lead Portfolio Manager

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

Fund's Positions

in Mentioned Holdings

as of 6/30/07

Nintendo	4.9	%
Potash Corp. of Saskatchewan	3.2	%
Hong Kong Exchanges and Clearing	3.2	%
Hexagon	2.7	%
Kenedix	2.3	%
Singapore Exchange	1.8	%
C&C Group	0.1	%

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

Columbia Acorn International Select climbed 7.38% in the second quarter, outpacing the 6.08% gain of the S&P/Citigroup World ex-US Cap Range $2-10B Index. Year to date, the Fund was up 11.80% vs. a 12.04% return for the index.

Japan's Nintendo continued to post strong returns in the second quarter, increasing 27%. For the first six months of the year, the stock was up 49% as sales of its Wii gaming system continue to break records and strong sales of its gaming software followed suit. Canada's Potash Corp. of Saskatchewan, the worlds' largest producer of potash, gained 48% in the quarter and was up 65% for the half year as increasing crop prices bode well for fertilizer prices. Sweden's Hexagon, a manufacturer of measurement equipment and polymers, increased 42% in the quarter and 35% for the six months on strong earnings news.

Increased liquidity and favorable earnings news boosted the performance of Asian markets, excluding Japan. The Fund's equity and derivatives market operators, Hong Kong Exchanges and Clearing and Singapore Exchange, both benefited from increased trading volumes. Hong Kong Exchanges and Clearing increased nearly 48% in the quarter and was up 32% for the half year. Singapore Exchange saw similar gains for the quarter, up 48%, and for the six months the stock was up 76%.

Laggards for the quarter included Kenedix, a Japanese real estate investment management company. The stock fell 27% in the quarter and was off 18% for the first half of the year due to the rise in interest rates in Japan and concerns that the real estate sector would suffer. Banca Italease, an Italian leasing and factoring company, fell 46% in the quarter and was sold out of the Fund as the company seriously misjudged the amount of exposure it had to interest rate derivatives, which could result in a required capital increase for the firm. Last year Irish beverage company C&C Group was a star performer for Columbia Acorn International Select but the stock has cooled in 2007. Company earnings and sales have declined due to increased competition and very poor summer weather. The stock fell 8% in the quarter and was down 21% year to date.

International investments involve greater potential risks, including less regulation, currency fluctuations, economic instability and political developments. Investments in small- and mid-cap companies may be subject to greater volatility and price fluctuations because they may be thinly traded and less liquid.

16

Columbia Acorn International Select (ACFFX)

At a Glance

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

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

through June 30, 2007

Inception 11/23/98	Year to date*			1 year			5 years			Life of fund
Returns before taxes		11.80	%		35.02	%		21.96	%		14.69	%
Returns after taxes on distributions		11.61			34.88			21.94			14.61
Returns after taxes on distributions and sale of fund shares		7.67			22.85			19.61			13.21
S&P/Citigroup World ex-US Cap Range $2-10B (pretax)		12.04			29.92			22.67			13.52

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.

*Year to date data not annualized.

Columbia Acorn International Select Portfolio Diversification

as a % of net assets as of 6/30/07

Columbia Acorn International Select Top 10 Holdings as a % of net assets as of 6/30/07

1.	Nintendo (Japan) Entertainment Software & Hardware	4.9	%
2.	Fugro (Netherlands) Oilfield Services	3.6	%
3.	CRH (Ireland) Global Building Materials	3.3	%
4.	Hong Kong Exchanges and Clearing (Hong Kong) Hong Kong Equity & Derivatives Market Operator	3.2	%
5.	Zumtobel (Austria) Lighting Systems	3.2	%
6.	Potash Corp. of Saskatchewan (Canada) World's Largest Producer of Potash	3.2	%
7.	Atwood Oceanics (United States) Offshore Drilling Contractor	3.1	%
8.	Synthes (Switzerland) Products for Orthopedic Surgery	3.1	%
9.	Smith & Nephew (United Kingdom) Medical Equipment & Supplies	3.0	%
10.	SES Global (France) Satellite Broadcasting Services	2.9	%

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 Select (Class Z)

November 23, 1998 through June 30, 2007

This graph compares the results of $10,000 invested in Columbia Acorn International Select at inception on November 23, 1998 to the S&P/Citigroup World ex-US Cap Range $2-10B 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: $222.0 million

17

Columbia Acorn Select

In a Nutshell

Ben Andrews

Lead Portfolio Manager

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

Fund's Positions

in Mentioned Holdings

as of 6/30/07
ITT Educational Services	4.8	%
Liberty Global	4.4	%
Potash Corp. of Saskatchewan	3.5	%
Tetra Technologies	1.8	%
American Commercial Lines	1.7	%
JB Hunt Transport Services	0.9	%

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

Columbia Acorn Select gained 9.12% in the second quarter, ahead of its benchmark, the S&P MidCap 400 Index, which returned 5.84%. The Fund also topped the S&P 500's return of 6.28% in the quarter. Year to date, Columbia Acorn Select was up 16.76% vs. 11.98% for the S&P MidCap 400 and 6.96% for the S&P 500.

The top three drivers of Fund performance were the same this quarter as last quarter: ITT Educational Services, Potash Corp. of Saskatchewan and Liberty Global. All three companies displayed strong fundamentals and their combined return accounted for 4.7% of the Fund's 16.76% return year to date.

We made a few structural adjustments to Columbia Acorn Select during the quarter. The minimum dollar amount to open a new account is now $100,000, up from $50,000, and all retirement plans are now subject to the new minimum. We currently manage about $3.2 billion in assets in Columbia Acorn Select. Cash inflows have been very strong so far this year and we hope to temper this with the higher minimum. At the end of the period, the Fund had 10% of its assets in cash. We are finding ideas to buy, however most are valued at levels that we are willing to pay to build a small position but we don't want to bet the ranch, at least not yet. We do not want to be forced into initiating bigger positions just to accommodate cash inflows. While we don't believe we are reaching capacity with this product in the long run, we would like to be prudent in the short term.

We also increased the number of stocks we are allowed to hold in the Fund. Columbia Acorn Select can now invest in generally 30 to 60 companies (currently we hold 39), an increase from the previous 20 to 40. We still plan on running a select portfolio. Since starting the Fund in 1998, we have had over 40% of our assets in our top 10 names and we don't see this changing. We also slightly increased the percentage of the Fund that we can invest in foreign companies. Currently we have approximately 10% of the Fund's assets invested in international stocks, mostly in the raw materials sector.

We added three stocks to the portfolio during the quarter: American Commercial Lines, JB Hunt Transport Services and Tetra Technologies. We sold out of two positions, Nuveen Investments and Weight Watchers International.

We sold Nuveen one month before it announced it was selling itself to a private equity firm. Our crystal ball was smudged and we did not see the take out coming, but should we have? We sold Nuveen because we were concerned with the direction it was taking with its asset management division. We believe Nuveen was purchased at a much higher price than we sold it at because money has been abundant and private equity can leverage cheap money and pay lofty multiples while infusing little equity. The Nuveen sale prompted me to go back and look at our other sales since I became portfolio manager of the Fund in early 2004. We exited 22 positions and had another three companies taken over for cash during the last three years. Looking back at the reasons we had for selling the positions, we were often right yet many of these stocks trade at higher prices. This exercise reminded us how easily mistakes are forgiven in bull markets; companie s can miss earnings estimates and growth can come in slower than Wall Street originally thought yet share prices can still go up. This is true for portfolio managers as well; most of us are putting up large returns during this period but will we keep these returns when the economy goes slack? When the market does cool, we believe owning the right stocks will be very important and having more structural flexibility within the Fund should help us to preserve capital. Thank you for your continued support of 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.

18

Columbia Acorn Select (ACTWX)

At a Glance

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

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

through June 30, 2007

Inception 11/23/98	Year to date*			1 year			5 years			Life of fund
Returns before taxes		16.76	%		32.54	%		18.46	%		16.43	%
Returns after taxes on distributions		16.58			31.98			18.12			15.91
Returns after taxes on distributions and sale of fund shares		10.97			21.62			16.24			14.56
S&P MidCap 400 (pretax)		11.98			18.51			14.17			12.69

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.

*Year to date data not annualized.

Columbia Acorn Select Portfolio Diversification

as a % of net assets as of 6/30/07

Columbia Acorn Select Top 10 Holdings

as a % of net assets as of 6/30/07

1.	Uranium One (South Africa) (previously UrAsia Energy) Uranium Mines in South Africa, Kazakhstan, Australia & the U.S.	6.2%
2.	ITT Educational Services Post-secondary Degree Programs	4.8%
3.	Tellabs Telecommunications Equipment	4.6%
4.	Liberty Global Cable TV Franchises outside the USA	4.4%
5.	Conseco Life, Long-term Care & Medical Supplement Insurance	4.3%
6.	Safeway Supermarkets	3.8%
7.	Abercrombie & Fitch Teen Apparel Retailer	3.8%
8.	Janus Capital Group Manages Mutual Funds	3.5%
9.	Potash Corp. of Saskatchewan (Canada) World's Largest Producer of Potash	3.5%
10.	Expedia Online Travel Services Company	3.2%

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 $100,000 Investment in Columbia Acorn Select (Class Z)*

November 23, 1998 through June 30, 2007

This graph compares the results of $100,000 invested in Columbia Acorn Select at inception on November 23, 1998 to the S&P MidCap 400. 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:
$3,206.1 million

* The minimum initial investment amount for Columbia Acorn Select was increased to $100,000 on June 25, 2007. Certain exclusions may apply.

19

Columbia Thermostat Fund

In a Nutshell

Charles P. McQuaid

Lead Portfolio Manager

Performance data quoted represents past performance and current performance may be lower or higher. Past performance is no guarantee of future results. The investment return and principal value of an investment in the Fund will fluctuate so that shares, when redeemed, may be worth more or less than the original cost. Performance may reflect any voluntary waivers or reimbursements of fund expenses by the Adviser or its affiliates. Absent these waivers, or reimbursement arrangements, performance results may be lower. Visit columbiafunds.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 ended the second quarter up 2.07% and posted a 4.43% year-to-date gain. Fund performance, as expected, was between the S&P 500 Index and the Lehman Brothers U.S. Credit Intermediate Bond Index for both time periods (see Page 2 for index data).

Fund returns came in below the 4.96% quarterly gain and 6.79% six-month increase of the Lipper Flexible Portfolio Funds Index. Key to its investment strategy, Columbia Thermostat Fund sells a portion of its stock funds when the S&P 500 goes up and invests more in bonds. Because 2007 has generally been a strong year for equities, Columbia Thermostat Fund has had more of its portfolio in bonds than the average fund in the Lipper Flexible Portfolio Funds Index. This dampened the Fund's relative returns in the first six months of this year. However, if the equity weakness that arose just following the period end persists, Columbia Thermostat Fund's relative performance is likely to improve. Additionally, our approach should automatically ensure that we are buying equities if there is a sustained drop in prices. At the end of the period, the Fund had a 35% exposure to stocks and a 65% exposure to bonds.

As the following table illustrates, the equity portion of the portfolio had impressive gains in the quarter and year to date through June 30, 2007. For the second quarter, the Fund's equity component was up 6.70% and, for the half year, it was up 9.71%. Columbia Acorn Select posted top gains for both time periods, followed by Columbia Acorn International and Columbia Acorn Fund. On the fixed income side, the Fund's income component was down 0.70% for the quarter and gained just 0.75% for the half year.

Results of the Funds Owned in Columbia Thermostat Fund

at June 30, 2007

Equities Fund	Weightings in Category			2nd quarter returns			Year-to-date returns to 6/30/07
Columbia Acorn Fund		15	%		6.70	%		11.55	%
Columbia Acorn Select		10	%		9.12	%		16.76	%
Columbia Marsico Growth Fund		15	%		5.34	%		6.01	%
Columbia Acorn International		15	%		8.61	%		14.59	%
Columbia Dividend Income Fund		20	%		5.69	%		7.88	%
Columbia Large Cap Enhanced Core Fund		25	%		6.17	%		6.60	%
Weighted Average Equity Return		100	%		6.70	%		9.71	%
Fixed Income Fund	Weightings in Category			2nd quarter returns			Year-to-date returns to 6/30/07
Columbia Federal Securities Fund		30	%		-1.06	%		0.28	%
Columbia Intermediate Bond Fund		50	%		-0.52	%		0.77	%
Columbia Conservative High Yield Fund		20	%		-0.64	%		1.42	%
Weighted Average Income Return		100	%		-0.70	%		0.75	%

Columbia Thermostat Fund Rebalancing in the Second Quarter

April 16, 2007:	35% stock, 65% bond
May 4, 2007:	30% stock, 70% bond
June 8, 2007:	35% stock, 65% bond

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 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. Small- and mid-cap stocks are often more volatile and less liquid than the stocks of larger companies. Small companies may have a shorter history of operations than larger companies and may have a less diversified product line, making them more susceptible to market pressure. International investments involve greater potential risks, including less regulation, currency fluctuations, economic instability and political developments. Changes in interest rates and changes in the financial strength of issu ers of lower-rated bonds may also affect underlying fund performance. The Fund is also subject to the risk that the investment adviser's decisions regarding asset classes and 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 (COTZX)

At a Glance

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

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

through June 30, 2007

Inception 9/25/02	Year to date*			1 year			3 year			Life of fund
Returns before taxes		4.43	%		12.88	%		9.07	%		11.26	%
Returns after taxes on distributions		3.87			10.33			7.03			9.84
Returns after taxes on distributions and sale of fund shares		3.32			9.62			6.96			9.21
S&P 500 (pretax)		6.96			20.59			11.68			15.68
Lehman Brothers U.S. Credit Intermediate Bond Index (pretax)		1.28			6.34			3.79			4.46
Lipper Flexible Portfolio Funds Index (pretax)		6.79			16.83			11.10			13.46

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.

*Year to date data not annualized.

Columbia Thermostat Fund Asset Allocation

as a % of net assets as of 6/30/07

Columbia Thermostat Fund Portfolio Weightings

as a % of assets in each investment category
as of 6/30/07

Stock Mutual Funds

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

Bond Mutual Funds

Columbia Intermediate Bond Fund	50	%
Columbia Federal Securities Fund	30	%
Columbia Conservative High Yield Fund	20	%

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

September 25, 2002 through June 30, 2007

This graph compares the results of $10,000 invested in Columbia Thermostat Fund at inception on September 25, 2002 to the S&P 500, the Lehman Brothers U.S. Credit Intermediate Bond Index and the Lipper Flexible Portfolio Funds Index. 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:
$180.0 million

21

Columbia Acorn Fund

Major Portfolio Changes in the Second Quarter (Unaudited)

	Number of Shares
	03/31/07		06/30/07
Additions
Information
Blackbaud		0		613,000
Ciena		0		370,000
Dolby Laboratories		0		250,000
Epicor		671,000		1,500,000
Equinix		190,000		225,000
Everlight Electronics (Taiwan)		3,198,000		6,400,000
FARO Technologies		685,000		860,000
II-VI		2,025,000		2,220,000
Informa Group (United Kingdom)		0		1,300,000
IPG Photonics		750,000		1,190,000
Kenexa		962,000		1,200,000
MetroPCS Communications		0		175,000
Microsemi		1,925,000		2,250,000
Polycom		1,060,000		1,250,000
Red Hat		0		900,000
Sanmina-SCI		10,000,000		14,522,000
Scientific Games		500,000		2,000,000
Switch & Data Facilities		370,000		877,000
Taylor Nelson Sofres (United Kingdom)		0		2,358,000
Tellabs		14,100,000		15,380,000
TheStreet.com		0		1,094,000
Time Warner Telecom		4,700,000		6,200,000
Trimble Navigation		2,900,000		3,070,000
Industrial Goods & Services
Albany International		234,000		700,000
American Commercial Lines		0		1,900,000
American Reprographics		1,500,000		2,000,000
Cytec Industries		0		400,000
Donaldson		3,800,000		4,000,000
Interline Brands		500,000		1,000,000
Intertek Testing (United Kingdom)		0		631,000
Kansai Paint (Japan)		0		124,000
Stork (Netherlands)		0		56,492
Union Tool (Japan)		44,300		360,000
Vulcan Materials		0		175,000
Wavin (Netherlands)		90,000		611,460
Consumer Goods & Services
Ambassadors Group		0		135,000
Hansen Natural		850,000		1,650,000
Herman Miller		2,500,000		3,800,000
NutriSystem		1,000,000		1,120,000
Thor Industries		441,000		561,000

	Number of Shares
	03/31/07		06/30/07
Finance
BOK Financial		2,605,000		2,852,000
CAI International		0		200,000
Conseco		4,000,000		5,000,000
First Financial Bankshares		286,000		386,000
HCC Insurance Holdings		3,125,000		3,600,000
MB Financial		0		700,000
Philadelphia Consolidated Holding		2,040,000		2,390,000
TriCo Bancshares		0		200,000
West Bancorporation		1,049,000		1,249,000
Energy & Minerals
Carrizo Oil & Gas		0		1,100,000
Dresser-Rand Group		0		552,000
Fugro (Netherlands)		3,418,301		3,584,037
SBM Offshore (Netherlands)		0		250,000
Tesco		190,000		1,044,000
Tetra Technologies		1,228,000		1,988,000
Health Care
Arena Pharmaceuticals		1,179,000		1,320,000
BioMarin		2,375,000		3,940,000
Collagenex Pharmaceuticals		1,000,000		1,200,000
Eresearch Technology		2,600,000		3,000,000
Healthcare Services Group		0		400,000
OPG Groep (Netherlands)		270,000		1,080,000
Pharmacopeia		0		825,000
QIAGEN		0		900,000
Seattle Genetics		3,300,000		3,720,000
Other Industries
Gaylord Entertainment		1,760,000		2,000,000
Jiangsu Expressway (China)		0		6,790,000

22

	Number of Shares
	03/31/07		06/30/07
Sales
Information
Activision		1,000,000		750,000
Advantech (Taiwan)		9,956,115		8,157,000
Alltel		1,200,000		0
Avnet		3,105,000		2,490,000
Cubic		273,000		0
Fair Isaac		916,000		0
Gemstar-TV Guide International		8,000,000		0
infoUSA		1,450,000		800,000
Jabil Circuit		1,320,000		690,000
JDA Software		1,490,000		0
Kronos		2,750,000		0
Liberty Media Corp-Interactive		655,000		0
NAVTEQ		1,400,000		1,200,000
Openwave Systems		2,500,000		1,500,000
Seachange International		964,000		0
SRA International		1,350,000		1,050,000
Supertex		950,000		820,000
TALX		865,000		0
THQ		2,300,000		2,000,000
WebEx		353,000		0
Industrial Goods & Services
Gardner Denver		350,000		0
Grafton Group (Ireland)		1,600,000		0
K&F Industries		1,712,000		0
Neopost (France)		140,000		112,000
Quanta Services		2,500,000		2,200,000
UTI Worldwide		3,000,000		2,700,000
Worthington Industries		1,800,000		1,500,000
Consumer Goods & Services
C&C Group (Ireland)		800,000		26,000
Central Parking		1,168,000		0
Ducati Motor (Italy)		5,700,000		5,410,390
Edgars Consolidated Stores (South Africa)		3,500,000		0
Fleetwood Enterprises		3,255,000		2,500,000
HNI		2,550,000		2,236,000
ITT Educational Services		2,250,000		2,000,000
Regis		800,000		0
Techtronic Industries (Hong Kong)		14,999,300		0
Williams-Sonoma		250,000		0
Winnebago		540,000		390,000

	Number of Shares
	03/31/07		06/30/07
Finance
Anchor Bancorp Wisconsin		1,178,000		978,000
Anglo Irish Bank (Ireland)		1,800,000		0
Banca Italease (Italy)		250,000		0
East West Bancorp		200,000		0
Northern Rock (United Kingdom)		2,500,000		0
Nuveen Investments		2,157,000		1,303,000
Paragon Group (United Kingdom)		1,000,000		0
RLI		570,000		0
SY Bancorp		48,000		0
Energy & Minerals
Key Energy Services		730,000		170,000
McMoran Exploration		870,000		470,000
Newpark Resources		310,000		0
St. Mary Land & Exploration		850,000		500,000
Vaalco Energy		3,200,000		2,750,000
Health Care
Cytokinetics		2,000,000		0
Dendrite International		1,433,000		0
Nuvelo		1,650,000		1,025,000
The Medicines Company		600,000		0
United Surgical Partners		1,150,000		0
Viasys Healthcare		1,200,000		0
Other Industries
DiamondRock Hospitality		3,700,000		3,500,000

23

Columbia Acorn Fund

Statement of Investments (Unaudited), June 30, 2007

Number of Shares			Value (000)
				Equities: 93.6%
Information 23.6%
		> Business Software 3.3%
	12,000,000	Novell (a)	$	93,480
		Directory, Operating System & Identity Management Software
	1,400,000	Micros Systems (a)		76,160
		Information Systems for Restaurants & Hotels
	3,300,000	Parametric Technology (a)		71,313
		Engineering Software & Services
	1,800,000	Avid Technology (a)		63,630
		Digital Nonlinear Editing Software & Systems
	4,000,000	Informatica (a)		59,080
		Enterprise Data Integration Software
	2,131,000	Concur Technologies (a)(b)		48,693
		Web Enabled Cost & Expense Management Software
	1,200,000	Kenexa (a)		45,252
		Recruiting and Workforce Management Solutions
	6,000,000	Actuate (a)(b)		40,740
		Information Delivery Software & Solutions
	1,800,000	Cadence Design Systems (a)		39,528
		Electronic Design Automation Software
	2,500,000	Radiant Systems (a)(b)		33,100
		Point of Sale Systems: Convenient Stores & Restaurants
	3,000,000	Lawson Software (a)		29,670
		Enterprise Resource Planning (ERP) Software
	3,500,000	Agile Software (a)(b)		28,210
		Product Design Software
	1,500,000	Epicor (a)		22,305
		Software Systems to Run Small Businesses
	900,000	Red Hat (a)		20,052
		Maintenance & Support for Opensource
	613,000	Blackbaud		13,535
		Software & Services for Non-Profits
	3,500,000	Tumbleweed Communications (a)(b)		8,925
		Email Content Security & File Transfer Management
				693,673
		> Computer Hardware & Related Equipment 3.0%
	3,800,000	Amphenol		135,470
		Electronic Connectors
	2,090,000	Belden CDT		115,681
		Specialty Cable
	2,220,000	II-VI (a)(b)		60,317
		Laser Components
	1,426,000	Nice Systems (Israel) (a)		49,539
		Audio & Video Recording Solutions
	460,000	Wincor Nixdorf (Germany)		42,636
		Retail POS Systems & ATM Machines
	860,000	Zebra Technologies (a)		33,316
		Bar Code Printers
	900,000	Netgear (a)		32,625
		Networking Products for Small Business & Home
	1,027,000	Avocent (a)		29,793
		Computer Control Switches
	8,157,000	Advantech (Taiwan)		26,050
		Embedded Computers

Number of Shares			Value (000)
	620,000	Rogers (a)	$	22,940
		PCB Laminates & High-performance Foams
	735,000	Excel Technology (a)(b)		20,536
		Laser Systems & Electro-optical Components
	375,000	Diebold		19,575
		Automated Teller Machines
	1,310,000	CTS		16,585
		Electronic Components, Sensors & Electronics Manufacturing Solutions
	325,000	Stratasys (a)		15,269
		Rapid Prototyping Systems
	500,000	Intermec (a)		12,655
		Bar Code & Wireless LAN Systems
	250,000	Dolby Laboratories (a)		8,853
		Audio Technology for Consumer Electronics
				641,840
		> Mobile Communications 2.1%
	4,500,000	Crown Castle International (a)		163,215
		Communications Towers
	3,500,000	American Tower (a)		147,000
		Communications Towers in USA & Mexico
	8,000,000	Dobson Communications (a)(b)		88,880
		Rural & Small City Cellular Telephone Services
	600,000	Telephone & Data Systems		37,542
		Cellular & Wireline Telephone Services
	1,500,000	Openwave Systems		9,390
		Internet Software for Mobile Devices
	600,000	Globalstar (a)		6,210
		Satellite Mobile Voice & Data Carrier
	175,000	MetroPCS Communications (a)		5,782
		Discount Cellular Telephone Services
				458,019
		> Instrumentation 2.1%
	2,800,000	Flir Systems (a)		129,500
		Infrared Cameras
	3,070,000	Trimble Navigation (a)		98,854
		GPS-based Instruments
	750,000	Mettler Toledo (a)		71,632
		Laboratory Equipment
	800,000	Varian (a)		43,864
		Analytical Instruments
	600,000	Dionex (a)		42,594
		Ion & Liquid Chromatography
	860,000	FARO Technologies (a)(b)		27,400
		Precision Measurement Equipment
	1,190,000	IPG Photonics (a)		23,741
		Fiber Lasers
				437,585
		> CATV 1.6%
	4,500,000	Discovery Holding (a)		103,455
		CATV Programming
	2,050,000	Liberty Global Series C (a)		80,565
	1,500,000	Liberty Global Series A (a)		61,560
		Cable TV Franchises Outside the USA
	70,000	Jupiter Telecommunications (Japan) (a)		57,722
		Largest Cable Service Provider in Japan
	130,000	Liberty Media Corp - Capital (a)		15,298
		CATV Holding Company

24

Number of Shares			Value (000)
		> CATV—continued
	1,250,000	Mediacom Communications (a)	$	12,113
		Cable Television Franchises
				330,713
		> Semiconductors & Related Equipment 1.5%
	4,800,000	Integrated Device Technology (a)		73,296
		Communications Semiconductors
	2,250,000	Microsemi (a)		53,887
		Analog/Mixed Signal Semiconductors
	4,425,000	Entegris (a)		52,569
		Semiconductor Wafer Shipping & Handling Products
	1,270,000	Littelfuse (a)(b)		42,888
		Little Fuses
	3,257,000	AMIS Holdings (a)		40,777
		Mixed-signal Semiconductors
	820,000	Supertex (a)(b)		25,699
		Mixed-signal Semiconductors
	6,400,000	Everlight Electronics (Taiwan)		22,868
		A Led Packager
	1,905,000	IXYS (a)(b)		15,907
		Power Semiconductors
				327,891
		> Gaming Equipment & Services 1.4%
	2,750,000	International Game Technology		109,175
		Slot Machines & Progressive Slots
	3,150,000	Bally Technologies (a)(b)		83,223
		Slot Machines & Software
	2,000,000	Scientific Games (a)		69,900
		Lottery Services Provider
	2,430,000	Shuffle Master (a)(b)		40,338
		Card Shufflers & Casino Games
				302,636
		> Internet Related 1.4%
	3,000,000	ValueClick (a)		88,380
		Internet Advertising
	9,500,000	SkillSoft (a)(b)		88,255
		Web-based Learning Solutions (E-Learning)
	4,000,000	CNET Networks (a)		32,760
		Internet Advertising on Niche Websites
	1,000,000	Sohu.com (China) (a)		31,990
		Advertising on Chinese Internet Portal
	225,000	Equinix (a)		20,581
		Network Neutral Data Centers
	877,000	Switch & Data Facilities (a)		16,829
		Network Neutral Data Centers
	1,094,000	TheStreet.com		11,903
		Financial Information Website Publisher
				290,698
		> Financial Processors 1.1%
	2,774,000	Global Payments		109,989
		Credit Card Processor
	6,500,000	Hong Kong Exchanges and Clearing (Hong Kong)		91,966
		Hong Kong Equity & Derivatives Market Operator
	5,000,000	Singapore Exchange (Singapore)		31,933
		Singapore Equity & Derivatives Market Operator
				233,888

Number of Shares			Value (000)
		> Telecommunications Equipment 1.1%
	15,380,000	Tellabs (a)	$	165,489
		Telecommunications Equipment
	1,250,000	Polycom (a)		42,000
		Video Conferencing Equipment
	370,000	Ciena (a)		13,368
		Optical Transport & Broadband Access Equipment
	1,510,000	Symmetricom (a)		12,684
		Network Timing & Synchronization Devices
				233,541
		> Business Information & Marketing Services 1.1%
	3,460,000	Ceridian (a)		121,100
		HR Services & Payment Processing
	2,300,000	Navigant Consulting (a)		42,688
		Financial Consulting Firm
	2,000,000	ProQuest (b)		19,080
		Education Services for the K-12 Market
	420,000	FTI Consulting (a)		15,973
		Financial Consulting Firm
	250,000	Getty Images (a)		11,952
		Photographs for Publications & Electronic Media
	2,358,000	Taylor Nelson Sofres (United Kingdom)		11,152
		Market Research
	800,000	infoUSA		8,176
		Business Data for Sales Leads
				230,121
		> Telephone Services 0.9%
	6,200,000	Time Warner Telecom (a)		124,620
		Fiber Optic Telephone/Data Services
	1,300,000	Cogent Communications (a)		38,831
		Internet Data Pipelines
	1,400,000	Windstream		20,664
		Rural Telephone Franchises
				184,115
		> Electronics Distribution 0.5%
	2,490,000	Avnet (a)		98,704
		Electronic Components Distribution
	710,000	Agilysys		15,975
		IT Distributor
				114,679
		> Contract Manufacturing 0.4%
	14,522,000	Sanmina-SCI (a)		45,454
		Electronic Manufacturing Services
	1,020,000	Plexus (a)		23,450
		Electronic Manufacturing Services
	690,000	Jabil Circuit		15,228
		Electronic Manufacturing Services
				84,132
		> Computer Services 0.4%
	5,000,000	iGate (a)(b)		40,100
		IT & Business Process Outsourcing Services
	1,050,000	SRA International (a)		26,523
		Government IT Services
	4,600,000	AnswerThink (a)(b)		16,652
		IT Integration & Best Practice Research
				83,275

25

Columbia Acorn Fund

Statement of Investments (Unaudited), continued

Number of Shares			Value (000)
		> Consumer Software 0.3%
	2,000,000	THQ (a)	$	61,040
		Entertainment Software
	750,000	Activision (a)		14,002
		Entertainment Software
				75,042
		> Television Programming 0.3%
	4,000,000	Lions Gate Entertainment (a)		44,120
		Film & TV Studio
	433,900	Alliance Atlantis Communication (Canada) (a)		21,299
		CATV Channels, TV/Movie Production/ Distribution
				65,419
		> Publishing 0.3%
	1,200,000	NAVTEQ (a)		50,808
		Map Data for Electronic Devices
	1,300,000	Informa Group (United Kingdom)		14,451
		Global Publisher & Event Organizer
				65,259
		> Satellite Broadcasting & Services 0.3%
	2,755,000	SES Global (France)		59,384
		Satellite Broadcasting Services
				59,384
		> Radio 0.3%
	1,541,000	Salem Communications (b)		17,090
		Radio Stations for Religious Programming
	1,500,000	Cumulus Media (a)		14,025
		Radio Stations in Small Cities
	1,400,000	Saga Communications (a)(b)		13,720
		Radio Stations in Small- & Mid- Sized Cities
	2,400,000	Spanish Broadcasting System (a)(b)		10,320
		Spanish Language Radio Stations
				55,155
		> TV Broadcasting 0.2%
	2,500,000	Entravision Communications (a)		26,075
		Spanish Language TV, Radio & Outdoor
	1,750,000	Gray Television		16,222
		Mid Market Affiliated TV Stations
				42,297
Information: Total				5,009,362
Industrial Goods & Services 18.1%
		> Machinery 5.5%
	5,000,000	Ametek		198,400
		Aerospace/Industrial Instruments
	4,000,000	Donaldson (b)		142,200
		Industrial Air Filtration
	3,500,000	Clarcor (b)		131,005
		Mobile & Industrial Filters
	2,850,000	Pentair		109,924
		Pumps & Water Treatment
	2,300,000	Pall		105,777
		Filtration & Fluids Clarification
	1,900,000	Mine Safety Appliances (b)		83,144
		Safety Equipment

Number of Shares			Value (000)
	2,200,000	ESCO Technologies (b)	$	79,772
		Automatic Electric Meter Readers
	1,300,000	Kaydon		67,756
		Specialized Friction & Motion Control Products
	750,000	Armor Holdings (a)		65,153
		Military Trucks, Armor & Helmets
	1,250,000	Nordson		62,700
		Dispensing Systems for Adhesives & Coatings
	833,000	Toro		49,055
		Turf Maintenance Equipment
	2,100,000	Goodman Global (a)		46,662
		HVAC Equipment Manufacturer
	112,000	Neopost (France)		16,380
		Postage Meter Machines
	360,000	Union Tool (Japan)		13,299
		Precision Drill Bit Manufacturer
				1,171,227
		> Other Industrial Services 3.1%
	5,500,000	Expeditors International of Washington		227,150
		International Freight Forwarder
	2,700,000	UTI Worldwide		72,333
		Global Logistics & Freight Forwarding
	1,900,000	Forward Air (b)		64,771
		Freight Transportation Between Airports
	2,000,000	American Reprographics (a)		61,580
		Document Management & Logistics
	1,750,000	Mobile Mini (a)		51,100
		Portable Storage Units Leasing
	1,900,000	American Commercial Lines (a)		49,495
		Operator of Inland Barges/Builder of Inland Barges
	2,000,000	Labor Ready (a)		46,220
		Temporary Manual Labor
	374,000	Imtech (Netherlands)		32,444
		Engineering & Technical Services
	600,000	G&K Services		23,706
		Uniform Rental
	655,000	TAL International Group		19,460
		Intermodal Freight Containers Leasing
	631,000	Intertek Testing (United Kingdom)		12,371
		Testing, Inspection, Certification Services
				660,630
		> Construction 1.9%
	1,900,000	Florida Rock		128,250
		Aggregates & Concrete
	650,000	Martin Marietta Materials		105,313
		Aggregates
	2,200,000	Simpson Manufacturing		74,228
		Wall Joint Maker
	300,000	Geberit (Switzerland)		51,187
		Plumbing Supplies
	175,000	Vulcan Materials		20,044
		Aggregates, Concrete & Asphalt
	700,000	Kingspan Group (Ireland)		19,575
		Building Insulation & Environmental Containers
				398,597

26

Number of Shares			Value (000)
		> Industrial Materials & Specialty Chemicals 1.7%
	590,000	Novozymes (Denmark)	$	68,394
		Industrial Enzymes
	28,000	Sika (Switzerland)		57,146
		Chemicals for Construction & Industrial Applications
	2,000,000	Spartech (b)		53,100
		Plastics Distribution & Compounding
	1,228,000	Drew Industries (a)(b)		40,696
		RV & Manufactured Home Components
	195,000	Sociedad Quimica y Minera de Chile (Chile)		33,548
		Producer of Specialty Fertilizers, Lithium, & Iodine
	400,000	Carbone Lorraine (France)		31,042
		Advanced Industrial Materials
	700,000	Albany International		28,308
		Paper Machine Clothing and Advanced Textiles
	400,000	Cytec Industries		25,508
		Aerospace Composites & Specialty Chemical
	441,384	Koninklijke TenCate (Netherlands)		16,895
		Advanced Textiles & Industrial Fabrics
	611,460	Wavin (Netherlands)		14,709
		Largest European Plastic Pipe Systems Company
	124,000	Kansai Paint (Japan)		1,083
		Paint Producer in Japan, India, China & Southeast Asia
				370,429
		> Industrial Distribution 1.7%
	2,375,000	Watsco (b)		129,200
		HVAC Distribution
	1,300,000	WW Grainger		120,965
		Industrial Distribution
	1,925,000	Airgas		92,207
		Industrial Gas Distributor
	1,000,000	Interline Brands (a)		26,080
		Industrial Distribution
				368,452
		> Electrical Components 1.3%
	2,600,000	Genlyte Group (a)(b)		204,204
		Commercial Lighting Fixtures
	700,000	Legrand (France)		25,191
		Electrical Components
	1,125,000	Ushio (Japan)		24,927
		Industrial Light Sources
	500,000	Zumtobel (Austria) (a)		18,651
		Lighting Systems
				272,973
		> Conglomerates 1.0%
	4,845,000	Hexagon (Sweden)		92,916
		Measurement Equipment & Polymers
	2,758,309	Aalberts Industries (Netherlands)		75,736
		Flow Control & Heat Treatment
	600,000	Ibiden (Japan)		38,634
		Electronic Parts & Ceramics
	56,492	Stork (Netherlands)		3,667
		Industrial Services & Food Processing Equipment
				210,953

Number of Shares			Value (000)
		> Outsourcing Services 0.8%
	2,200,000	Quanta Services (a)	$	67,474
		Electrical & Telecom Construction Services
	1,900,000	Administaff (b)		63,631
		Professional Employer Organization
	817,021	USG People (Netherlands)		38,383
		Temporary Staffing Services
	600,000	GP Strategies (a)		6,528
		Training Programs
				176,016
		> Steel 0.7%
	2,860,000	Gibraltar Industries (b)		63,349
		Steel Processing & Building Products
	135,000	Vallourec (France)		43,143
		Oil, Gas & Industrial Seamless Tubes
	1,500,000	Worthington Industries		32,475
		Steel Processing & Manufactured Metal Products
				138,967
		> Waste Management 0.4%
	2,550,000	Waste Connections (a)		77,112
		Solid Waste Management
				77,112
Industrial Goods & Services: Total				3,845,356
Consumer Goods & Services 18.1%
		> Retail 4.1%
	3,140,000	Abercrombie & Fitch		229,157
		Teen Apparel Retailer
	9,130,000	Chico's FAS (a)(b)		222,224
		Women's Specialty Retailer
	4,600,000	Urban Outfitters (a)		110,538
		Apparel & Home Specialty Retailer
	1,975,000	J Crew Group (a)		106,828
		Multi-channel Branded Retailer
	3,743,000	Christopher & Banks (b)		64,192
		Women's Apparel Retailer
	1,223,000	AnnTaylor Stores (a)		43,319
		Women's Apparel Retailer
	1,954,600	RONA (Canada) (a)		40,826
		Leading Canadian Do-it-yourself Retailer
	775,000	Genesco (a)		40,540
		Multi-concept Branded Footwear Retailer
	1,200,000	Gaiam (a)(b)		21,876
		Healthy Living Catalogs & E-commerce
				879,500
		> Other Consumer Services 2.5%
	2,000,000	ITT Educational Services (a)		234,760
		Post-secondary Degree Programs
	5,400,000	ServiceMaster		83,484
		Lawn Care, Pest Control, Commercial Disaster Responce
	1,120,000	NutriSystem (a)		78,221
		Weight Loss Programs
	1,275,000	Weight Watchers International		64,821
		Weight Loss Programs
	1,500,000	Universal Technical Institute (a)(b)		38,085
		Vocational Training

27

Columbia Acorn Fund

Statement of Investments (Unaudited), continued

Number of Shares			Value (000)
		> Other Consumer Services—continued
	110,000	Pierre & Vacances (France)	$	16,782
		Vacation Apartment Lets
	2,550,000	Princeton Review (a)(b)		12,189
		College Preparation Courses
	100,000	Lincoln Technical Institute (a)		1,486
		Vocational Training
				529,828
		> Apparel 2.5%
	7,330,000	Coach (a)		347,369
		Designer & Retailer of Branded Leather Accessories
	1,069,000	Oxford Industries (b)		47,399
		Branded & Private Label Apparel
	1,818,000	Carter's (a)		47,159
		Children's Branded Apparel
	3,000,000	Billabong International (Australia)		45,426
		Action Sports Apparel Brand Manager
	900,000	True Religion Apparel (a)		18,297
		Premium Denim
	600,000	Heelys (a)		15,516
		Wheeled Footwear
				521,166
		> Leisure Products 1.7%
	1,500,000	Harley-Davidson		89,415
		Motorcycles & Related Merchandise
	1,416,000	Speedway Motorsports		56,612
		Motorsport Racetrack Owner & Operator
	1,025,000	International Speedway		54,028
		Largest Motorsports Racetrack Owner & Operator
	900,000	Polaris Industries		48,744
		Leisure Vehicles & Related Products
	1,032,000	RC2 (a)		41,290
		Toys, Infant Products & Collectibles
	561,000	Thor Industries		25,323
		RV & Bus Manufacturer
	2,500,000	Fleetwood Enterprises (a)		22,625
		RV & Manufactured Home Maker
	390,000	Winnebago		11,513
		Premier Motorhome Maker
				349,550
		> Nondurables 1.6%
	2,860,000	Scotts Miracle-Gro		122,808
		Consumer Lawn & Garden Products
	2,060,000	Jarden (a)		88,601
		Branded Household Products
	1,010,000	Chattem (a)(b)		64,014
		Personal Care Products
	1,800,000	Helen of Troy (a)(b)		48,600
		Hair Dryers & Curling Irons
	1,100,000	Natura Cosmeticos (Brazil)		15,967
		Direct Retailer of Cosmetics
				339,990
		> Furniture & Textiles 1.4%
	3,800,000	Herman Miller (b)		120,080
		Office Furniture
	2,236,000	HNI		91,676
		Office Furniture & Fireplaces

Number of Shares			Value (000)
	1,818,000	Knoll	$	40,723
		Office Furniture
	3,144,000	Nobia (Sweden)		39,129
		Kitchen Cabinet Manufacturing & Distribution
				291,608
		> Travel 1.3%
	2,390,000	Vail Resorts (a)(b)		145,479
		Ski Resort Operator & Developer
	4,000,000	Expedia (a)		117,160
		Online Travel Services Company
	425,000	Choice Hotels		16,796
		Franchisor of Budget Hotel Brands
	135,000	Ambassadors Group		4,797
		Educational Student Travel Services
				284,232
		> Casinos & Gaming 1.2%
	1,700,000	Penn National Gaming (a)		102,153
		Regional Casino Operator
	3,200,000	Pinnacle Entertainment (a)(b)		90,080
		Regional Casino Operator
	400,000	Station Casinos		34,720
		Las Vegas Locals Casinos
	690,000	Intralot (Greece)		22,228
		Lottery & Gaming Systems & Services
	226,000	Lakes Entertainment (a)		2,669
		Native American Casinos Development
				251,850
		> Restaurants 0.7%
	2,145,000	Sonic (a)		47,447
		Quick Service Restaurant
	1,000,000	Red Robin Gourmet Burgers (a)(b)		40,370
		Casual Dining Restaurant
	1,150,000	Cheesecake Factory (a)		28,198
		Casual Dining Restaurants
	1,600,000	AFC Enterprises (a)(b)		27,664
		Popeyes Restaurants
				143,679
		> Consumer Goods Distribution 0.5%
	2,890,000	Pool (b)		112,797
		Distributor of Swimming Pool Supplies & Equipment
				112,797
		> Food & Beverage 0.4%
	1,650,000	Hansen Natural (a)		70,917
		Alternative Beverages
	1,000,000	IAWS Group (Ireland)		20,947
		Baked Goods
	26,000	C&C Group (Ireland)		349
		Beverage Company
				92,213
		> Other Durable Goods 0.1%
	5,410,390	Ducati Motor (Italy) (a)		13,169
		Motorcycles & Related Merchandise
	900,000	Champion Enterprises (a)		8,847
		Manufactured Homes
	172,000	Cavco Industries (a)		6,453
		Higher End Manufactured Homes
				28,469

28

Number of Shares			Value (000)
		> Cruise Lines 0.1%
	400,000	Carnival	$	19,508
		Largest Cruise Line
				19,508
Consumer Goods & Services: Total				3,844,390
Finance 12.3%
		> Insurance 3.9%
	3,600,000	HCC Insurance Holdings		120,276
		Specialty Insurance
	5,000,000	Conseco (a)		104,450
		Life, Long Term Care, & Medical Supplement Insurance
	2,390,000	Philadelphia Consolidated Holding (a)		99,902
		Specialty Insurance
	149,000	Markel (a)		72,199
		Specialty Insurance
	1,200,000	Assurant		70,704
		Specialty Insurance
	1,748,000	Leucadia National		61,617
		Insurance Holding Company
	995,000	Protective Life		47,571
		Life Insurance
	1,000,000	Endurance Specialty Holdings		40,040
		Commercial Lines Insurance/Reinsurance
	740,000	Stancorp Financial Group		38,835
		Group Life & Disability Insurance
	1,550,000	United America Indemnity (a)(b)		38,548
		Specialty Insurance
	1,420,000	Selective Insurance Group		38,170
		Commercial & Personal Lines Insurance
	750,000	Delphi Financial Group		31,365
		Group Employee Benefit Products & Services
	1,000,000	Aspen Insurance		28,070
		Commercial Lines Insurance/Reinsurance
	600,000	National Financial Partners		27,786
		Distributor of Life Insurance, Group Benefits & Investment Advisory Services
	280,000	April Group (France)		14,750
		Insurance Policy Construction
				834,283
		> Banks 3.0%
	2,852,000	BOK Financial		152,354
		Tulsa Based S.W. Bank
	3,450,000	Associated Banc-Corp		112,815
		Midwest Bank
	3,156,000	TCF Financial		87,737
		Great Lakes Bank
	4,080,000	Glacier Bancorp (b)		83,028
		Mountain States Bank
	1,222,000	Chittenden		42,709
		New England Bank
	1,320,000	West Coast Bancorp (b)		40,115
		Portland Small Business Bank
	700,000	MB Financial		24,318
		Chicago Bank
	1,249,000	West Bancorporation (b)		19,946
		Des Moines Commercial Bank

Number of Shares			Value (000)
	1,000,000	Depfa Bank (Ireland)	$	17,706
		Investment Banker to Public Authorities
	636,000	Great Southern Bancorp		17,204
		Missouri Real Estate Lender
	386,000	First Financial Bankshares		14,980
		West Texas Bank
	400,000	First Mutual Bancshares (b)		8,892
		Seattle Community Bank
	250,000	First Busey		4,997
		Illinois Bank
	150,000	Greene County Bancshares		4,689
		Tennessee Bank
	200,000	TriCo Bancshares		4,472
		California Central Valley Community Bank
				635,962
		> Brokerage & Money Management 2.4%
	5,500,000	Eaton Vance		242,990
		Specialty Mutual Funds
	5,948,000	SEI Investments		172,730
		Mutual Fund Administration & Investment Management
	1,303,000	Nuveen Investments		80,981
		Money Management
	450,000	Investment Technology Group (a)		19,499
		Electronic Trading
				516,200
		> Finance Companies 1.5%
	6,500,000	AmeriCredit (a)(b)		172,575
		Auto Lending
	1,500,000	World Acceptance (a)(b)		64,095
		Personal Loans
	1,219,000	McGrath Rentcorp		41,068
		Temporary Space & IT Rentals
	900,000	Marlin Business Services (a)(b)		19,179
		Small Equipment Leasing
	1,203,000	Electro Rent		17,492
		Test & Measurement Rentals
	200,000	CAI International (a)		2,636
		International Container Leasing & Management
				317,045
		> Savings & Loans 1.5%
	9,085,000	People's United		161,077
		Connecticut Savings & Loan
	1,700,000	Housing Development Finance (India)		84,475
		Indian Mortgage Lender
	1,285,000	Washington Federal		31,238
		Traditional Thrift
	978,000	Anchor Bancorp Wisconsin		25,614
		Wisconsin Thrift
	360,000	Provident New York Bancorp		4,864
		New York State Thrift
				307,268
Finance: Total				2,610,758

29

Columbia Acorn Fund

Statement of Investments (Unaudited), continued

Number of Shares			Value (000)
Energy & Minerals 8.7%
		> Oil & Gas Producers 4.0%
	2,500,000	XTO Energy	$	150,250
		Oil & Gas Producer
	2,700,000	Ultra Petroleum (a)		149,148
		Oil & Gas Producer
	2,400,000	Equitable Resources		118,944
		Natural Gas Producer & Utility
	4,900,000	Talisman Energy (Canada)		94,757
		Oil & Gas Producer
	9,315,000	Tullow Oil (United Kingdom)		90,769
		Oil & Gas Producer
	2,000,000	Southwestern Energy (a)		89,000
		Oil & Gas Producer
	1,500,000	Range Resources		56,115
		Oil & Gas Producer
	1,100,000	Carrizo Oil & Gas (a)		45,617
		Explores for Natural Gas & Crude Oil
	700,000	Denbury Resources (a)		26,250
		Oil Producer Using Co2 Injection
	500,000	St. Mary Land & Exploration		18,310
		Oil & Gas Producer
	2,750,000	Vaalco Energy (a)		13,283
		Oil & Gas Producer
	470,000	McMoran Exploration (a)		6,580
		Natural Gas Producer & Developer
				859,023
		> Oil Services 3.8%
	3,584,037	Fugro (Netherlands) (b)		227,455
		Oilfield Services
	2,820,000	FMC Technologies (a)		223,400
		Oil & Gas Well Head Manufacturer
	1,200,000	Atwood Oceanics (a)		82,344
		Offshore Drilling Contractor
	1,761,000	Rowan		72,166
		Offshore Drilling Contractor
	1,988,000	Tetra Technologies (a)		56,062
		U.S.-based Services Company with Life of Field Approach
	1,044,000	Tesco (a)		32,938
		Developing New Well Drilling Technologies
	750,000	CARBO Ceramics		32,858
		Natural Gas Well Stimulants
	1,001,000	ShawCor (Canada)		30,737
		Oil & Gas Pipeline Products
	552,000	Dresser-Rand Group (a)		21,804
		Largest Manufacturer of Compressors
	1,580,000	Enerflex Systems (Canada)		15,633
		Natural Gas Compresser Rental & Fabrication
	250,000	SBM Offshore (Netherlands)		9,530
		Builds & Leases Offshore Vessels to Process & Store Crude Oil
	170,000	Key Energy Services (a)		3,150
		Well Workover Services
				808,077
		> Mining 0.6%
	5,895,000	Uranium One (South Africa) (a)		75,095
		Uranium Mines in South Africa, Kazakhstan, Australia & the U.S.

Number of Shares			Value (000)
	2,900,000	Jubilee Mines (Australia)	$	39,163
		Nickel Mining in Australia
	1,000,000	Ivanhoe Mines (Canada) (a)		14,175
		Copper Mine Project in Mongolia
				128,433
		> Agricultural Commodities 0.2%
	550,000	Aracruz Celulose (Brazil)		36,432
		Brazilian Hardwood Pulp Producer
				36,432
		> Oil Refining, Marketing & Distribution 0.1%
	435,000	Oneok		21,928
		Natural Gas Distribution, Pipeline Processing & Trading
				21,928
Energy & Minerals: Total				1,853,893
Health Care 7.9%
		> Health Care Services 1.9%
	1,000,000	Rhoen-Klinikum (Germany)		60,256
		Health Care Services
	1,085,000	Charles River Laboratories (a)		56,008
		Pharmaceutical Research
	1,125,000	LCA-Vision (b)		53,167
		Lasik Surgery Centers
	1,300,000	Lincare Holdings (a)		51,805
		Home Health Care Services
	2,250,000	PSS World Medical (a)		40,995
		Medical Supplies
	1,080,000	OPG Groep (Netherlands)		39,327
		Health Care Supplies & Pharmacies
	900,000	Omnicare		32,454
		Pharmacy Services for Nursing Homes
	500,000	Coventry Health Care (a)		28,825
		HMO
	3,000,000	Eresearch Technology (a)(b)		28,530
		Clinical Research Services
	400,000	Healthcare Services Group		11,800
		Outsourced Services to Long-term Care Industry
				403,167
		> Medical Supplies 1.9%
	1,910,000	Cytyc (a)		82,340
		Consumables Related to Women's Health
	1,250,000	ICU Medical (a)(b)		53,675
		Intravenous Therapy Products
	929,000	Henry Schein (a)		49,637
		Largest Distributor of Healthcare Products
	1,200,000	Owens & Minor		41,928
		Distribution of Medical Supplies
	1,025,000	Polymedica		41,871
		Diabetes Supply Distributor
	700,000	Cooper		37,324
		Contact Lens Manufacturer
	905,000	Arrow International		34,644
		Disposable Catheters
	486,000	Techne (a)		27,804
		Cytokines, Antibodies & Other Reagents for Life Science

30

Number of Shares			Value (000)
		> Medical Supplies—continued
	790,000	Meridian Biosciences	$	17,111
		Niche Diagnostics/Life Science Company
	900,000	QIAGEN (a)		16,011
		Life Science Company; DNA/RNA Purification
				402,345
		> Biotechnology & Drug Delivery 1.7%
	3,940,000	BioMarin (a)		70,684
		Biotech Focused on Orphan Diseases
	2,550,000	PDL BioPharma (a)		59,415
		Proprietary Monoclonal Antibodies
	3,720,000	Seattle Genetics (a)(b)		36,493
		Antibody-based Therapies for Cancer
	865,000	Amylin (a)		35,603
		Biotech Company Focused on Diabetes & Obesity
	2,000,000	Medarex (a)		28,580
		Humanized Antibodies
	2,160,000	Array Biopharma (a)		25,207
		Drugs for Cancer & Inflammatory Diseases
	650,000	Myriad Genetics (a)		24,173
		Drugs/Diagnostics Hybrid
	1,650,000	Nektar Therapeutics (a)		15,659
		Drug Delivery Technologies
	1,320,000	Arena Pharmaceuticals (a)		14,507
		Novel Drug Targeting Technology
	3,100,000	Lexicon Genetics (a)		9,951
		Drug Discovery
	2,520,000	Decode Genetics (a)		9,412
		Drugs for Heart Attack, Asthma & Vascular Disease
	1,229,000	Neurogen (a)		8,161
		Development-stage Biotech Focused on Neurology
	1,750,000	Genitope (a)		6,755
		Cancer Vaccine
	1,100,000	La Jolla Pharmaceutical (a)		4,928
		Lupus Treatment
	825,000	Pharmacopeia (a)		4,579
		Biotech Company with Broad Early-stage Pipeline
	1,025,000	Nuvelo (a)		2,788
		Development-stage Biotech Focused on Cardiovascular/Cancer
	1,875,000	Locus Discovery, Series D, Pfd. (a)(c)		544
	966,441	Locus Discovery, Series B, Pfd. (a)(c)		280
		High Throughput Rational Drug Design
	1,249,999	Perlegen Sciences (a)(c)		400
		Large Scale Gene Sequencing
	359,944	MicroDose Technologies (a)(c)		360
		Drug Inhaler Development
				358,479
		> Medical Equipment & Devices 1.3%
	1,000,000	Edwards Lifesciences (a)		49,340
		Heart Valves
	870,000	Vital Signs (b)		48,328
		Anesthesia, Respiratory & Sleep Products
	943,000	Orthofix International (a)(b)		42,407
		Bone Fixation & Stimulation Devices
	315,000	Synthes (Switzerland)		37,806
		Products for Orthopedic Surgery

Number of Shares			Value (000)
	550,000	Dade Behring	$	29,216
		Clinical Diagnostics Supplier
	550,000	Haemonetics (a)		28,935
		Blood & Plasma Collection Equipment
	552,000	Advanced Medical Optics (a)		19,254
		Medical Devices for Eye Care
	140,000	Essilor International (France)		16,675
		Eyeglass Lenses
				271,961
		> Pharmaceuticals 1.1%
	900,000	Cephalon (a)		72,351
		Specialty Pharmaceuticals for Pain, Central Nervous System & Oncology
	1,295,000	Endo Pharmaceuticals (a)		44,328
		Specialty Pharmaceuticals for Pain Management
	1,000,000	Medicis Pharmaceutical		30,540
		Specialty Pharmaceuticals for Dermatology
	1,010,000	MGI Pharma (a)		22,594
		Specialty Pharmaceuticals for Oncology & Acute Care
	3,000,000	QLT (a)		22,200
		Specialty Pharmaceuticals for Ophthalmology & Dermatology
	3,100,000	United Drug (Ireland)		16,928
		Irish Pharmaceutical Wholesaler & Outsourcer
	1,200,000	Collagenex Pharmaceuticals (a)(b)		14,880
		Specialty Pharmaceuticals for Dermatology
	1,700,000	Barrier Therapeutics (a)(b)		11,050
		Specialty Pharmaceuticals for Dermatology
				234,871
Health Care: Total				1,670,823
Other Industries 4.9%
		> Real Estate 3.8%
	5,850,000	Highland Hospitality (b)		112,320
		Hotel Owner
	2,000,000	Gaylord Entertainment (a)		107,280
		Convention Hotels
	1,398,000	Forest City Enterprises, Class B (b)		86,690
		Commercial & Residential Property Developer
	650,000	SL Green Realty		80,528
		Manhattan Office Buildings
	1,320,000	General Growth Properties		69,894
		Regional Shopping Malls
	3,500,000	DiamondRock Hospitality		66,780
		Hotel Owner
	635,000	Macerich Company		52,337
		Regional Shopping Malls
	575,000	Federal Realty Investment Trust		44,425
		Shopping Centers
	1,720,000	Kite Realty Group (b)		32,714
		Community Shopping Centers
	850,000	Digital Realty Trust		32,028
		Technology-focused Office Buildings
	1,375,000	Crescent Real Estate Equities		30,855
		Class 'A' Office Buildings
	628,000	Parkway Properties		30,163
		Office Buildings

31

Columbia Acorn Fund

Statement of Investments (Unaudited), continued

Number of Shares or Principal Amount (000)			Value (000)
		> Real Estate—continued
	1,020,000	Brandywine Realty	$	29,152
		Office Buildings
	900,000	American Campus Communities		25,461
		Student Housing
	8,200	Kenedix (Japan)		15,252
		Real Estate Investment Management
	37,407	Security Capital European Realty (Luxembourg) (a)(c)(d)		—
		Self Storage Properties
				815,879
		> Transportation 0.8%
	1,556,000	JB Hunt Transport Services		45,622
		Truck & Intermodal Carrier
	826,200	Grupo Aeroportuario del Surest (Mexico)		43,533
		Cancun & Cozumel Airport Operator
	14,120,000	China Shipping Development (China)		32,569
		China's Dominant Shipper for Oil & Coal
	1,914,000	Heartland Express		31,198
		Regional Trucker
	6,790,000	Jiangsu Expressway (China)		6,906
		Chinese Toll Road Operator
				159,828
		> Regulated Utilities 0.3%
	1,650,000	Northeast Utilities		46,794
		Regulated Electric Utility
	340,000	Red Electrica de Espana (Spain)		15,932
		Spanish Power Grid
				62,726
Other Industries: Total				1,038,433
Total Equities: 93.6% (Cost: $11,345,002)				19,873,015
Short-Term Obligations 6.1%
$	50,000	Ebbetts Funding (e) 5.28% Due 7/11/07		49,927
	50,000	St. Germain Holdings (e) 5.28% Due 7/27/07		49,809
	50,000	Four Winds Funding (e) 5.27% Due 7/30/07		49,788
	50,000	Four Winds Funding (e) 5.27% Due 7/31/07		49,780
	50,000	Manhattan Asset Funding (e) 5.28% Due 8/01/07		49,773
	50,000	Liberty Street Funding (e) 5.28% Due 8/15/07		49,670
	48,000	Morrigan TRR (e) 5.28% Due 7/17/07		47,888
	45,000	Pasa Funding (e) 5.27% Due 7/19/07		44,881
	45,000	Ebury Finance (e) 5.28% Due 7/25/07		44,842
	45,000	White Point Funding (e) 5.29% Due 8/13/07		44,716

Principal Amount (000)			Value (000)
$	44,000	Hannover Funding (e) 5.28% Due 7/06/07	$	43,968
	44,000	World Omni Vehicles (e) 5.26% Due 7/09/07		43,949
	44,000	World Omni Vehicles (e) 5.26% Due 7/10/07		43,942
	44,000	Axon Financial (e) 5.28% Due 8/09/07		43,748
	44,000	Axon Financial (e) 5.28% Due 8/10/07		43,742
	43,000	Nightingale (e) 5.28% Due 8/08/07		42,760
	40,000	Ebbetts Funding (e) 5.27% Due 7/16/07		39,912
	40,000	Mica Funding LLC (e) 5.28% Due 8/06/07		39,789
	38,000	Mica Funding LLC (e) 5.26% Due 7/12/07		37,939
	38,000	Keel Capital (e) 5.27% Due 7/13/07		37,933
	38,000	Ebury Finance (e) 5.27% Due 7/24/07		37,872
	38,000	White Point Funding (e) 5.28% Due 8/14/07		37,755
	37,000	Mainsail II Ltd. (e) 5.27% Due 7/20/07		36,897
	37,000	Morrigan TRR (e) 5.28% Due 7/23/07		36,881
	36,000	La Fayette Asset Securitization LLC (e) 5.28% Due 7/03/07		35,989
	36,000	Anglesea Funding (e) 5.26% Due 7/05/07		35,979
	35,000	Anglesea Funding (e) 5.26% Due 7/02/07		34,995
	30,000	East Fleet Financial (e) 5.28% Due 7/26/07		29,890
	30,000	Pasa Funding (e) 5.27% Due 8/02/07		29,859
	28,000	Manhattan Asset Funding (e) 5.27% Due 8/03/07		27,865
	25,000	Morrigan TRR (e) 5.28% Due 7/18/07		24,938
	23,000	Mica Funding LLC (e) 5.28% Due 8/07/07		22,875
	7,804	Repurchase Agreement with Fixed Income Clearing Corp., dated 6/29/07, due 7/02/07 at 5.050%, collateralized by a U.S. Government Agency Obligation, maturing 7/18/11, market value $7,960 (repurchase proceeds $7,807)		7,804
		(Amortized Cost: $1,298,355)		1,298,355
Total Investments: 99.7% (Cost: $12,643,357)(f)(g)				21,171,370
Cash and Other Assets Less Liabilities: 0.3%				59,908
Total Net Assets: 100%			$	21,231,278

32

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

(a)  Non-income producing security.

(b)  An affiliate may include any company in which the Fund owns five percent or more of its outstanding voting shares. Transactions in affiliated companies during the six months ended June 30, 2007, are as follows:

Affiliates	Balance of Shares Held 12/31/06		Purchases/ Additions		Sales/ Reductions		Balance of Shares Held 6/30/07		Value		Dividend
Actuate		6,000,000		-		-		6,000,000	$	40,740	$	-
Administaff		1,670,000		230,000		-		1,900,000		63,631		407
AFC Enterprises		1,600,000		-		-		1,600,000		27,664		-
Agile Software		3,500,000		-		-		3,500,000		28,210		-
AmeriCredit		6,500,000		-		-		6,500,000		172,575		-
Anchor Bancorp Wisconsin*		1,178,000		-		200,000		978,000		25,614		401
AnswerThink		4,600,000		-		-		4,600,000		16,652		-
Bally Technologies		3,500,000		-		350,000		3,150,000		83,223		-
Barrier Therapeutics		1,321,000		379,000		-		1,700,000		11,050		-
Chattem		1,010,000		-		-		1,010,000		64,014		-
Chico's FAS		7,080,000		2,050,000		-		9,130,000		222,224		-
Christopher & Banks		3,743,000		-		-		3,743,000		64,192		449
Clarcor		3,500,000		-		-		3,500,000		131,005		508
Collagenex Pharmaceuticals		830,000		370,000		-		1,200,000		14,880		-
Concur Technologies		2,131,000		-		-		2,131,000		48,693		-
Cytokinetics*		486,000		-		486,000		-		-		-
Dobson Communications		8,000,000		-		-		8,000,000		88,880		-
Donaldson		3,600,000		400,000		-		4,000,000		142,200		666
Drew Industries		1,228,000		-		-		1,228,000		40,696		-
Enerflex Systems*		2,280,000		-		700,000		1,580,000		15,633		640
Eresearch Technology		2,300,000		700,000		-		3,000,000		28,530		-
ESCO Technologies		2,200,000		-		-		2,200,000		79,772		-
Excel Technology		625,000		110,000		-		735,000		20,536		-
FARO Technologies		-		860,000		-		860,000		27,400		-
First Mutual Bancshares		400,000		-		-		400,000		8,892		72
Fleetwood Enterprises*		4,690,000		-		2,190,000		2,500,000		22,625		-
Forest City Enterprises, Class B		1,398,000		-		-		1,398,000		86,690		196
Forward Air		1,900,000		-		-		1,900,000		64,771		266
Fugro		2,928,301		655,736		-		3,584,037		227,455		3,860
Gaiam		1,200,000		-		-		1,200,000		21,876		-
Genlyte Group		1,963,000		637,000		-		2,600,000		204,204		-
Gibraltar Industries		2,860,000		-		-		2,860,000		63,349		429
Glacier Bancorp		4,080,000		-		-		4,080,000		83,028		979
Helen of Troy		1,800,000		-		-		1,800,000		48,600		-
Herman Miller		2,068,000		1,732,000		-		3,800,000		120,080		482
Highland Hospitality		5,850,000		-		-		5,850,000		112,320		1,346
HNI*		2,550,000		-		314,000		2,236,000		91,676		978
ICU Medical		1,083,000		167,000		-		1,250,000		53,675		-
iGate		5,000,000		-		-		5,000,000		40,100		-
II-VI		2,025,000		195,000		-		2,220,000		60,317		-
Indus International (merged into Vista Equity)*		5,600,000		-		5,600,000		-		-		-
ITT Educational Services*		2,250,000		-		250,000		2,000,000		234,760		-
IXYS		1,905,000		-		-		1,905,000		15,907		-
JDA Software*		1,490,000		-		1,490,000		-		-		-
Kite Realty Group		1,720,000		-		-		1,720,000		32,714		671
Kronos (merged into Helman & Friedman)*		2,750,000		-		2,750,000		-		-		-
LCA-Vision		1,125,000		-		-		1,125,000		53,167		405
Littelfuse		1,135,000		135,000		-		1,270,000		42,888		-
Marlin Business Services		685,000		215,000		-		900,000		19,179		-
Mine Safety Appliances		1,900,000		-		-		1,900,000		83,144		760
Orthofix International		942,500		500		-		943,000		42,407		-
Oxford Industries		919,000		150,000		-		1,069,000		47,399		358
Pinnacle Entertainment		3,200,000		-		-		3,200,000		90,080		-
Pool		2,500,000		390,000		-		2,890,000		112,797		636
Princeton Review		2,550,000		-		-		2,550,000		12,189		-
ProQuest		2,000,000		-		-		2,000,000		19,080		-
Radiant Systems		2,500,000		-		-		2,500,000		33,100		-
Red Robin Gourmet Burgers		1,000,000		-		-		1,000,000		40,370		-
Saga Communications		1,400,000		-		-		1,400,000		13,720		-
Salem Communications		1,541,000		-		-		1,541,000		17,090		-
Seachange International*		1,875,000		-		1,875,000		-		-		-
Seattle Genetics		2,300,000		1,420,000		-		3,720,000		36,493		-
Shuffle Master		2,430,000		-		-		2,430,000		40,338		-
Skillsoft		9,500,000		-		-		9,500,000		88,255		-
Spanish Broadcasting System		2,400,000		-		-		2,400,000		10,320		-
Spartech		2,700,000		-		700,000		2,000,000		53,100		635
Supertex		690,000		260,000		130,000		820,000		25,699		-
Tumbleweed Communications		3,500,000		-		-		3,500,000		8,925		-

33

Columbia Acorn Fund

Statement of Investments (Unaudited), continued

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

Affiliates	Balance of Shares Held 12/31/06		Purchases/ Additions		Sales/ Reductions		Balance of Shares Held 6/30/07		Value		Dividend
United America Indemnity		1,550,000		-		-		1,550,000		38,548		-
Universal Technical Institute		1,500,000		-		-		1,500,000		38,085		-
Vaalco Energy*		3,200,000		-		450,000		2,750,000		13,283		-
Vail Resorts		2,390,000		-		-		2,390,000		145,479		-
Vital Signs		870,000		-		-		870,000		48,328		165
Watsco		2,375,000		-		-		2,375,000		129,200		1,378
West Bancorporation		949,000		300,000		-		1,249,000		19,946		330
West Coast Bancorp		1,320,000		-		-		1,320,000		40,115		317
Witness Systems*		2,500,000				2,500,000		-		-
World Acceptance		1,500,000		-		-		1,500,000		64,095		-
TOTAL OF AFFILIATED TRANSACTIONS		193,338,801		11,356,236		19,985,000		184,710,037	$	4,477,872	$	17,334

*  At June 30, 2007, the Fund owned less than five percent of the company's outstanding voting shares.

  The aggregate cost and value of these companies at June 30, 2007, was $2,646,859 and $4,477,872 respectively. Investments in affiliate companies represent 21.09% of total net assets at June 30, 2007.

(c)  Denotes a restricted security, which is subject to restrictions on resale under federal securities laws. These securities, are valued in good faith by the Board of Trustees. At June 30, 2007, these securities had an aggregate value of $1,584 which represented 0.01% of total net assets.

  Additional information on these securities is as follows:

Security	Acquisition Dates	Shares		Cost		Value
Perlegen Sciences	3/30/01		1,249,999	$	4,500	$	400
Locus Discovery, Series D Pfd.	9/5/01		1,875,000		7,500		544
MicroDose Technologies	11/24/00		359,944		2,005		360
Locus Discovery, Series B Pfd.	2/8/07		966,441		280		280
Security Capital European Realty	8/20/98 - 11/12/99		37,407		205		-
				$	14,490	$	1,584

(d)  Security has no value.

(e)  Security exempt from registration under Section 4(2) of the Securities Act of 1933. These securities may only be resold in exempt transactions to qualified buyers. Private resales of these securities to qualified instutional buyers are also exempt from registration pursuant to Rule 144A under the Securities Act of 1933. At June 30, 2007, these securities had an aggregate value of $1,290,551, which represented 6.1% of net assets.

(f)  At June 30, 2007, for federal income tax purposes cost of investments was $12,643,357 and net unrealized appreciation was $8,528,013 consisting of gross unrealized appreciation of $8,815,065 and gross unrealized depreciation of $287,052.

(g)  On June 30, 2007, the market value of foreign securities represents 11.5% of total net assets. The Fund's foreign portfolio was diversified as follows:

	Value		Percent
Netherlands	$	458,146		2.16	%
France		223,347		1.05
Canada		217,427		1.02
Japan		150,917		0.71
Switzerland		146,139		0.69
Sweden		132,045		0.62
United Kingdom		128,743		0.61
Germany		102,892		0.48
Hong Kong		91,966		0.43
Australia		84,589		0.40
India		84,475		0.40
Ireland		75,505		0.36
South Africa		75,095		0.35
China		71,465		0.34
	Value		Percent
Denmark	$	68,394		0.32	%
Brazil		52,399		0.25
Israel		49,539		0.23
Taiwan		48,918		0.23
Mexico		43,533		0.21
Chile		33,548		0.16
Singapore		31,933		0.15
Greece		22,228		0.10
Austria		18,651		0.09
Spain		15,932		0.08
Italy		13,169		0.06
Luxembourg		-		-
Total Foreign Portfolio	$	2,440,995		11.50	%

34

Columbia Acorn International

Major Portfolio Changes in the Second Quarter (Unaudited)

	Number of Shares
	03/31/07		06/30/07
Additions
Europe
> Netherlands
Aalberts Industries		480,000		1,947,042
Boskalis Westminster		163,000		489,000
Fugro		1,271,700		1,406,155
Koninklijke TenCate		973,000		1,096,000
OPG Groep		191,000		764,000
SBM Offshore		0		450,000
Smit Internationale		520,000		680,000
Stork		0		825,000
Wavin		840,000		1,182,536
> France
Rubis		298,818		332,020
Trigano		500,000		571,000
> Germany
Deutsche Beteiligungs		283,000		354,500
Deutsche Boerse		120,000		200,000
MPC Muechmeyer Petersen Capital		0		300,000
> Switzerland
Kuehne & Nagel		550,000		600,000
Nobel Biocare Holding		95,000		140,000
Synthes		330,000		360,000
> United Kingdom
Informa Group		0		1,400,000
Intertek Testing		0		517,000
Northgate		1,450,000		1,875,000
Rotork		0		448,000
Smith & Nephew		2,205,000		2,670,000
Taylor Nelson Sofres		4,620,000		5,922,000
> Ireland
Kingspan Group		1,035,000		1,050,000
United Drug		8,050,000		8,100,000
> Sweden
Hexagon		1,553,500		3,960,000
Nobia		755,000		2,265,000
SWECO		610,000		3,135,000
> Spain
Prisa		800,000		1,050,000
Sogecable		400,000		520,000
> Greece
Intralot		1,300,000		1,630,000

	Number of Shares
	03/31/07		06/30/07
Asia
> Japan
Aeon Delight		0		95,000
As One		396,000		585,000
FCC		900,000		1,150,000
Kansai Paint		3,700,000		6,000,000
Kansai Urban Banking		0		4,100,000
Nakanishi		92,000		145,000
Topcon		0		650,000
Unicharm PetCare		0		105,000
Union Tool		403,600		500,000
Yusen Air & Sea Service		1,273,900		1,300,000
> China
China Green		22,049,000		25,051,000
Fu Ji Food & Catering Services		4,782,000		6,256,000
Hopewell Highway Infrastructure		0		20,000,000
Jiangsu Expressway		0		17,918,000
Travelsky Technology		6,758,000		20,910,000
Xinyu Hengdeli		0		6,008,000
> Hong Kong
EganaGoldpfeil		26,600,000		29,344,000
Hong Kong Exchanges and Clearing		5,026,000		5,500,000
> South Korea
Sung Kwang Bend		714,000		915,000
> India
United Phosphorus		0		192,000
Other Countries
> United States
BioMarin		0		524,000
Dresser-Rand Group		0		500,000
FMC Technologies		189,000		379,000
Tesco		119,239		273,000
> New Zealand
Sky City Entertainment		5,661,208		5,773,789
Latin America
> Brazil
Localiza Rent A Car		500,000		1,500,000
> Mexico
Grupo Aeroportuario del Surest		411,000		500,000

35

Columbia Acorn International

Major Portfolio Changes in the Second Quarter (Unaudited) continued

	Number of Shares
	03/31/07		06/30/07
Sales
Europe
> Netherlands
USG People		1,103,000		929,361
> France
Neopost		200,000		160,000
> Germany
Gagfah		150,000		0
Hugo Boss Designs		525,000		425,000
> United Kingdom
Debt Free Direct		1,300,000		1,000,000
Keller Group		1,000,000		650,000
Northern Rock		2,100,000		0
Paragon Group		3,500,000		371,000
Workspace Group		2,450,000		1,280,000
> Ireland
Anglo Irish Bank		1,300,000		0
Bank of Ireland		2,000,000		845,000
C&C Group		1,260,000		255,000
Grafton Group		1,850,000		1,040,000
Ryanair		500,000		0
> Italy
Banca Italease		590,000		0
Ducati Motor		13,400,000		12,531,048
> Spain
Red Electrica de Espana		567,000		400,000

	Number of Shares
	03/31/07		06/30/07
Asia
> Japan
Chiba Bank		2,000,000		1,500,000
Daito Trust Construction		546,000		375,000
Hiroshima Bank		2,248,000		0
Hogy Medical		321,300		53,000
> Hong Kong
Melco-PBL Entertainment Macau		200,000		0
Techtronic Industries		14,000,000		0
> South Korea
Woongjin Thinkbig		183,500		0
Other Countries
> Canada
Major Drilling Group		530,000		0
Northern Orion Resources		839,000		0
Railpower Technologies		1,778,000		0
UrAsia Energy		6,775,000		0
> South Africa
Edgars Consolidated Stores		4,530,000		0
Latin America
> Brazil
Brascan Residential Properties		492,000		0
> Mexico
Grupo Aeroportuario Centro Norte		200,000		0
Grupo Aeroportuario del Pacifica		100,000		0

36

Columbia Acorn International

Statement of Investments (Unaudited), June 30, 2007

Number of Shares			Value (000)
				Equities: 91.9%
Europe 51.6%
		> Netherlands 9.3%
	1,406,155	Fugro	$	89,239
		Oilfield Services
	825,000	Stork		53,550
		Industrial Services & Food Processing Equipment
	1,947,042	Aalberts Industries		53,461
		Flow Control & Heat Treatment
	680,000	Smit Internationale		53,209
		Harbor & Offshore Towage & Marine Services
	929,361	USG People		43,660
		Temporary Staffing Services
	1,096,000	Koninklijke TenCate		41,953
		Advanced Textiles & Industrial Fabrics
	479,000	Imtech		41,552
		Engineering & Technical Services
	1,385,000	Unit 4 Agresso (a)		37,517
		Business & Security Software
	1,182,536	Wavin		28,447
		Largest European Plastic Pipe Systems Company
	764,000	OPG Groep		27,821
		Health Care Supplies & Pharmacies
	489,000	Boskalis Westminster		19,440
		Dredging & Maritime Contractor
	450,000	SBM Offshore		17,153
		Builds & Leases Offshore Vessels to Process & Store Crude Oil
				507,002
		> France 8.4%
	3,000,000	SES Global		64,665
		Satellite Broadcasting Services
	600,000	Carbone Lorraine		46,562
		Advanced Industrial Materials
	390,000	Iliad		39,404
		Alternative Internet & Telecoms Provider
	375,000	Norbert Dentressangle		36,304
		Transport
	571,000	Trigano		33,816
		Leisure Vehicles & Camping Equipment
	206,000	Pierre & Vacances		31,429
		Vacation Apartment Lets
	332,020	Rubis		29,711
		Tank Storage & LPG Supplier
	190,000	Bacou Dalloz		28,883
		Safety Equipment
	700,000	Legrand		25,191
		Electrical Components
	240,000	Imerys		24,341
		Industrial Minerals Producer
	160,000	Neopost		23,399
		Postage Meter Machines
	100,000	Ciments Francais		22,933
		Leading French & Emerging Markets Cement Producer
	240,000	Eurofins Scientific (b)		20,377
		Food Screening & Testing
	350,000	April Group		18,437
		Insurance Policy Construction

Number of Shares			Value (000)
	360,000	Meetic (b)	$	15,291
		Dating Services
				460,743
		> Germany 6.7%
	900,000	Rhoen-Klinikum		54,230
		Health Care Services
	775,000	CTS Eventim		38,171
		Event Ticket Sales
	400,000	Wincor Nixdorf		37,074
		Retail POS Systems & ATM Machines
	300,000	MPC Muechmeyer Petersen Capital		30,670
		Alternative Asset Manager
	250,000	Vossloh		29,346
		Rail Infrastructure & Diesel Locomotives
	15,000	Porsche		26,704
		Specialty Automobile Manufacturer
	525,000	GFK		25,928
		Market Research Services
	425,000	Hugo Boss Designs		25,446
		Fashion Apparel
	267,000	Elringklinger		24,359
		Automobile Components
	200,000	Deutsche Boerse		22,661
		Trading, Clearing, Settlement Services for Financial Markets
	100,000	Rational		19,595
		Commercial Oven Manufacturer
	870,000	Takkt		15,493
		Mail Order Retailer of Office & Warehouse Durables
	354,500	Deutsche Beteiligungs		14,384
		Private Equity Investment Management
				364,061
		> Switzerland 6.0%
	600,000	Kuehne & Nagel		55,263
		Freight Forwarding/Logistics
	24,000	Sika		48,983
		Chemicals for Construction & Industrial Applications
	140,000	Nobel Biocare Holding		45,713
		Dental Implants & Ceramic Crowns
	360,000	Synthes		43,207
		Products for Orthopedic Surgery
	250,000	Geberit		42,655
		Plumbing Supplies
	140,000	Burckhardt Compression (b)		33,925
		Gas Compression Pumps
	375,000	Schindler		24,862
		Elevator Manufacturer & Service Provider
	25,000	Givaudan		24,686
		Fragrances & Flavors
	400,000	Logitech International (b)		10,599
		Branded Peripheral Computer Devices
				329,893
		> United Kingdom 5.9%
	1,970,714	Expro International Group		38,416
		Offshore Oilfield Services
	1,875,000	Northgate		38,413
		Light Commercial Vehicle Rental Specialist

37

Columbia Acorn International

Statement of Investments (Unaudited), continued

Number of Shares			Value (000)
		> United Kingdom—continued
	5,040,000	RPS Group	$	35,304
		Environmental Consulting & Planning
	2,670,000	Smith & Nephew		33,041
		Medical Equipment & Supplies
	3,255,691	Tullow Oil		31,725
		Oil & Gas Producer
	5,922,000	Taylor Nelson Sofres		28,007
		Market Research
	3,007,000	BBA Group		16,307
		Aviation Support Services
	1,400,000	Informa Group		15,563
		Global Publisher & Event Organizer
	640,000	Randgold Resources		14,202
		Gold Mining in Western Africa
	650,000	Keller Group		14,020
		International Ground Engineering Specialist
	1,280,000	Workspace Group		10,262
		UK Real Estate
	517,000	Intertek Testing		10,136
		Testing, Inspection, Certification Services
	1,275,000	Detica		9,814
		UK IT Services Company
	1,436,000	Mears Group		9,347
		Social Housing Mainentance
	448,000	Rotork		8,174
		Valve Actuators for Oil & Water Pipelines
	1,000,000	Debt Free Direct		4,755
		Consumer Debt Reduction & Management Solutions
	371,000	Paragon Group		3,631
		UK Buy-to-let Finance Company
				321,117
		> Ireland 3.4%
	8,100,000	United Drug		44,231
		Irish Pharmaceutical Wholesaler & Outsourcer
	1,800,000	IAWS Group		37,705
		Baked Goods
	1,050,000	Kingspan Group		29,362
		Building Insulation & Environmental Containers
	1,300,000	Depfa Bank		23,018
		Investment Banker to Public Authorities
	600,000	Paddy Power		18,706
		Irish Betting Services
	845,000	Bank of Ireland		17,123
		Irish Commercial Bank
	1,040,000	Grafton Group		14,837
		Builders Materials Wholesaling & Do-it-yourself Retailing
	255,000	C&C Group		3,420
		Beverage Company
				188,402
		> Sweden 2.4%
	3,960,000	Hexagon		75,944
		Measurement Equipment & Polymers
	3,135,000	SWECO		30,042
		Engineering Consultants
	2,265,000	Nobia		28,189
		Kitchen Cabinet Manufacturing & Distribution
				134,175

Number of Shares			Value (000)
		> Italy 2.2%
	9,100,000	CIR	$	34,997
		Italian Holding Company
	12,531,048	Ducati Motor (b)		30,501
		Motorcycles & Related Merchandise
	3,000,000	Amplifon		24,927
		Hearing Aid Retailer
	1,223,000	GranitiFiandre		15,532
		Innovative Stoneware
	375,000	Sabaf		14,295
		Supplier to White Goods Original Equipment Manufacturers
				120,252
		> Spain 1.2%
	1,050,000	Prisa		23,092
		Leading Spanish-speaking Publisher
	520,000	Sogecable (b)		21,767
		Spain's Main Pay-TV
	400,000	Red Electrica de Espana		18,744
		Spanish Power Grid
				63,603
		> Austria 1.1%
	965,000	Zumtobel (b)		35,996
		Lighting Systems
	300,000	Wienerberger		22,123
		Bricks & Clay Roofing Tiles
				58,119
		> Russia 1.0%
	775,000	Novolipetsk Steel		22,746
		Vertically Integrated Steel Producer
	486,000	RosBusinessConsulting (b)		17,496
		Financial Information, Media & IT Services in Russia
	370,000	Mechel Steel Group		13,516
		Coking Coal
				53,758
		> Greece 1.0%
	1,630,000	Intralot		52,509
		Lottery & Gaming Systems & Services
				52,509
		> Poland 0.7%
	1,125,500	Central European Distribution (b)		38,965
		Vodka Production & Alcohol Distribution
				38,965
		> Finland 0.7%
	1,756,000	Poyry		38,934
		Engineering Consultants
				38,934
		> Czech Republic 0.6%
	183,000	Komercni Banka		34,069
		Leading Czech Universal Bank
				34,069
		> Denmark 0.6%
	265,000	Novozymes		30,719
		Industrial Enzymes
				30,719

38

Number of Shares			Value (000)
		> Norway 0.4%
	2,354,000	Kongsberg Automotive (a)	$	19,731
		Automotive Seating & Component Supplier
				19,731
Europe: Total				2,816,052
Asia 25.2%
		> Japan 13.3%
	6,000,000	Kansai Paint		52,411
		Paint Producer in Japan, India, China & Southeast Asia
	730,000	Ibiden		47,005
		Electronic Parts & Ceramics
	1,205,000	Aeon Mall		36,964
		Suburban Shopping Mall Developer, Owner & Operator
	43,500	Jupiter Telecommunications (b)		35,870
		Largest Cable Service Provider in Japan
	1,080,000	Hoya		35,745
		Opto-electrical Components & Eyeglass Lenses
	16,000	Kenedix		29,760
		Real Estate Investment Management
	1,218,000	JSR		29,334
		Films & Chemicals for LCD Screens & Electronics
	1,272,000	Ushio		28,184
		Industrial Light Sources
	1,300,000	Yusen Air & Sea Service		27,785
		Airfreight Logistics
	816,200	Kintetsu World Express		27,647
		Airfreight Logistics
	430,000	USS		27,369
		Used Car Auctioneer
	1,150,000	FCC		23,617
		Auto/Motorcycle Clutches
	718,000	Ito En		23,582
		Bottled Tea & Other Beverages
	2,000,000	Park24		20,081
		Parking Lot Operator
	7,000	Risa Partners		19,021
		NPL & Real Estate Related Investment
	500,000	Union Tool		18,471
		Precision Drill Bit Manufacturer
	14,000	FullCast (a)		18,403
		Employment Outsourcing
	145,000	Nakanishi		18,099
		Dental Tools & Machinery
	375,000	Daito Trust Construction		17,842
		Apartment Builder
	1,140,000	Cosel		16,520
		Industrial Standard Switching Power Supply System
	965,000	T. Hasegawa		16,064
		Industrial Flavors & Fragrances
	585,000	As One		15,068
		Scientific Supplies Distributor
	4,100,000	Kansai Urban Banking		14,215
		Regional Bank
	1,500,000	Chiba Bank		13,313
		Regional Bank

Number of Shares			Value (000)
	380,000	Takata	$	13,245
		Safety Related Auto Parts
	370,000	Shimano		12,679
		Bicycle Components & Fishing Tackle
	2,400	Osaka Securities Exchange		11,071
		Osaka Securities Exchange
	650,000	Topcon		10,818
		Positioning & Medical Instrument
	1,230,000	Kamigumi		10,662
		Port Cargo Handling & Logistics
	1,500,000	Bank of Fukuoka		9,895
		Regional Bank
	643,000	Ain Pharmaciez (a)		9,813
		Dispensing Pharmacy/Drugstore Operator
	72,000	Hirose Electric		9,457
		Electrical Connectors
	374,000	Nagaileben		7,215
		Medical/Health Care Related Clothes
	1,650	Japan Pure Chemical		6,486
		Precious Metal Plating Chemicals for Electronics
	3,300	Message		5,353
		Nursing Care Facility Operator
	105,000	Unicharm PetCare		4,228
		Pet Food & Pet Toiletries
	95,000	Aeon Delight		2,898
		Facility Maintenance & Management
	53,000	Hogy Medical		2,366
		Disposable Surgical Products
				728,556
		> China 3.9%
	23,547,000	China Shipping Development		54,313
		China's Dominant Shipper for Oil & Coal
	48,430,000	Lenovo Group		28,527
		Third Largest PC Vendor Globally
	25,051,000	China Green		23,071
		An Agricultural Grower & Processor in China
	6,256,000	Fu Ji Food & Catering Services		21,445
		Food Catering Service Provider In China
	20,000,000	Hopewell Highway Infrastructure		18,731
		Guangdong Tollroad Leading to Hong Kong & Macau
	17,918,000	Jiangsu Expressway		18,225
		Chinese Toll Road Operator
	20,910,000	Travelsky Technology		17,870
		Online Air Travel Bookings in China
	21,750,000	TPV Technology		15,035
		Original Design Manufacturer for LCD Monitor & Flat TV
	400,000	Sohu.com (b)		12,796
		Advertising on Chinese Internet Portal
	6,008,000	Xinyu Hengdeli		2,947
		A High-end Watch Retailer in China
				212,960
		> Hong Kong 2.2%
	5,500,000	Hong Kong Exchanges and Clearing		77,817
		Hong Kong Equity & Derivatives Market Operator
	29,344,000	EganaGoldpfeil		25,706
		A Leather & Fashion Accessories Brand Manager

39

Columbia Acorn International

Statement of Investments (Unaudited), continued

Number of Shares			Value (000)
		> Hong Kong—continued
	5,000,000	Lifestyle International	$	19,378
		Mid to High-end Department Store Operator in Hong Kong & China
				122,901
		> South Korea 1.7%
	444,000	Taewoong		31,144
		A Player in the Niche Customized Forging Market
	160,000	MegaStudy		31,081
		Online Education Service Provider
	915,000	Sung Kwang Bend		27,053
		A Large Customized Industrial Pipe Fitting Manufacturer
	262,000	YBM Sisa.com		5,031
		Online Language Educator & Tester
				94,309
		> India 1.5%
	1,300,000	Housing Development Finance		64,598
		Indian Mortgage Lender
	700,000	Asian Paints		14,250
		India's Largest Paint Company
	192,000	United Phosphorus		1,482
		Off-patent Crop Protection Chemicals
				80,330
		> Singapore 1.2%
	7,000,000	Singapore Exchange		44,707
		Singapore Equity & Derivatives Market Operator
	13,000,000	ComfortDelGro		18,527
		Taxi & Mass Transit Service
				63,234
		> Taiwan 1.1%
	6,958,367	Advantech		22,222
		Embedded Computers
	7,280,000	Wah Lee Industrial		16,478
		Distributor of Chemicals, Materials & Equipment
	3,500,000	Everlight Electronics		12,506
		A Led Packager
	795,826	Formosa International Hotels		8,565
		Hotel, Food & Beverage Operation & Hospitality Management Services
				59,771
		> Indonesia 0.3%
	15,000,000	Perusahaan Gas Negara		15,668
		Gas Pipeline Operator
				15,668
Asia: Total				1,377,729
Other Countries 10.4%
		> Australia 2.8%
	3,000,000	Billabong International		45,426
		Action Sports Apparel Brand Manager
	750,000	Australian Stock Exchange		30,851
		Australian Equity & Derivatives Market Operator
	2,000,000	Jubilee Mines		27,009
		Nickel Mining in Australia

Number of Shares			Value (000)
	5,480,000	Sino Gold (b)	$	25,957
		Gold Mining in The People's Republic of China
	350,000	Perpetual Trustees		23,183
		Mutual Fund Management
				152,426
		> Canada 2.6%
	1,860,000	ShawCor		57,114
		Oil & Gas Pipeline Products
	1,663,500	RONA (b)		34,746
		Leading Canadian Do-it-yourself Retailer
	950,000	Van Houtte (a)		22,188
		Coffee Services & Equipment
	865,000	Talisman Energy		16,727
		Oil & Gas Producer
	850,000	Ivanhoe Mines (b)		12,049
		Copper Mine Project in Mongolia
				142,824
		> United States 2.3%
	865,000	Atwood Oceanics (b)		59,356
		Offshore Drilling Contractor
	379,000	FMC Technologies (b)		30,024
		Oil & Gas Well Head Manufacturer
	500,000	Dresser-Rand Group (b)		19,750
		Largest Manufacturer of Compressors
	524,000	BioMarin (b)		9,401
		Biotech Focused on Orphan Diseases
	273,000	Tesco (b)		8,613
		Developing New Well Drilling Technologies
				127,144
		> South Africa 2.3%
	1,440,000	Impala Platinum Holdings		43,657
		Platinum Group Metals Mining & Refining
	1,560,000	Naspers		39,960
		Media & Education in Africa & Other Emerging Markets
	3,048,750	Uranium One (b)		38,837
		Uranium Mines in South Africa, Kazakhstan, Australia & the U.S.
				122,454
		> New Zealand 0.4%
	5,773,789	Sky City Entertainment		22,572
		Casino/Entertainment Complex
				22,572
Other Countries: Total				567,420
Latin America 4.7%
		> Brazil 2.6%
	4,300,000	Suzano		58,180
		Brazilian Pulp & Paper Producer
	2,500,000	Natura Cosmeticos		36,288
		Direct Retailer of Cosmetics
	720,000	Porto Seguro		27,621
		Auto & Life Insurance
	1,500,000	Localiza Rent A Car		16,913
		Car Rental
				139,002

40

Number of Shares or Principal Amount (000)			Value (000)
		> Mexico 1.6%
	7,000,000	Urbi Desarrollos Urbanos (b)	$	32,235
		Affordable Housing Builder
	18,000,000	Consorcio ARA		28,991
		Affordable Housing Builder
	500,000	Grupo Aeroportuario del Surest		26,345
		Cancun & Cozumel Airport Operator
				87,571
		> Chile 0.5%
	160,000	Sociedad Quimica y Minera de Chile		27,526
		Producer of Specialty Fertilizers, Lithium, & Iodine
				27,526
Latin America: Total				254,099
Total Equities: 91.9% (Cost: $3,002,695)				5,015,300
Short-Term Obligations 7.3%
$	27,200	Pasa Funding (c) 5.31% Due 7/13/07		27,152
	27,000	Advantage Asset (c) 5.32% Due 7/12/07		26,956
	27,000	Gotham Funding (c) 5.30% Due 7/16/07		26,940
	27,000	Mont Blanc Capital (c) 5.30% Due 7/24/07		26,909
	26,900	Beethoven Funding (c) 5.35% Due 7/23/07		26,812
	26,800	Coast Asset (c) 5.31% Due 7/11/07		26,761
	26,500	St. Germain Holdings (c) 5.33% Due 7/10/07		26,465
	26,400	Bavaria (c) 5.29% Due 7/5/07		26,384
	26,300	Mica Funding LLC (c) 5.29% Due 7/2/07		26,296
	26,300	Versailles LLC (c) 5.29% Due 7/3/07		26,292
	26,300	Whistlejacket Capital (c) 5.32% Due 7/9/07		26,269
	23,200	Morrigan TRR (c) 5.33% Due 7/17/07		23,145
	22,000	East Fleet Financial (c) 5.31% Due 7/6/07		21,984
	20,000	Manhattan Asset Funding (c) 5.31% Due 7/18/07		19,950
	18,000	Cairn High Grade LLC (c) 5.30% Due 7/20/07		17,950
	15,000	White Point Funding (c) 5.32% Due 7/19/07		14,960

Principal Amount (000)			Value (000)
$	7,601	Repurchase Agreement with Fixed Income Clearing Corp., dated 6/29/07, due 7/02/07 at 5.050%, collateralized by a U.S. Government Agency Obligation, maturing 7/18/11, market value $7,756 (repurchase proceeds $7,604)	$	7,601
		(Amortized Cost: $398,826)		398,826
Total Investments: 99.2% (Cost: $3,401,521)(d)(e)				5,414,126
Cash and Other Assets Less Liabilities: 0.8%				44,604
Total Net Assets: 100%			$	5,458,730

41

Columbia Acorn International

Statement of Investments (Unaudited), continued

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

(a)  An affiliate may include any company in which the Fund owns five percent or more of its outstanding voting shares. Transactions in these affiliated companies during the six months ended June 30, 2007, are as follows:

Affiliates	Balance of Shares Held 12/31/2006		Purchases/ Additions		Sales/ Reductions		Balance of Shares Held 6/30/2007		Value		Dividend
AIN Pharmaciez		643,000		-		-		643,000	$	9,813	$	91
FullCast		-		14,000		-		14,000		18,403		112
Kongsberg Automotive		2,065,000		289,000		-		2,354,000		19,731		386
Unit 4 Agresso		1,385,000		-		-		1,385,000		37,517		1,194
Van Houtte		950,000		-		-		950,000		22,188		245
TOTAL OF AFFILIATED TRANSACTIONS		5,043,000		303,000		-		5,346,000	$	107,652	$	2,028

  The aggregate cost and value of these companies at June 30, 2007, was $102,622 and $107,652, respectively. Investments in affiliate companies represented 2.0% of total net assets at June 30, 2007.

(b)  Non-income producing security.

(c)  Security exempt from registration under Section 4(2) of the Securities Act of 1933. These securities may only be resold in exempt transactions to qualified buyers. Private resales of these securities to qualified institutional buyers are also exempt from registration pursuant to Rule 144A under the Securities Act of 1933. At June 30, 2007, these securities amounted to $391,225, which represented 7.2% of net assets.

(d)  At June 30, 2007 for federal income tax purposes cost of investments was $3,401,521 and net unrealized appreciation was $2,012,605 consisting of gross unrealized appreciation of $2,090,136 and gross unrealized depreciation of $77,531.

(e)  On June 30, 2007, the Fund's total investments were denominated in currencies as follows:

Currency	Value		% of Total Net Assets
Euro	$	1,853,624		34.0	%
Japanese Yen		728,556		13.3
US Dollar		699,562		12.8
Swiss Franc		329,893		6.0
Hong Kong Dollar		323,065		5.9
British Pounds		306,915		5.6
Other currencies less than 5% of total net assets		1,172,511		21.6
	$	5,414,126		99.2	%

42

Columbia Acorn International

Portfolio Diversification

At June 30, 2007, the Fund's portfolio investments as a percent of net assets was diversified as follows:

	Value (000)		Percent
> Industrial Goods & Services
Materials & Specialty Chemicals	$	448,628		8.2	%
Other Industrial Services		328,110		6.0
Conglomerates		229,960		4.2
Machinery		209,206		3.9
Construction		148,935		2.7
Outsourcing & Training Services		126,130		2.3
Electrical Components		115,348		2.1
Industrial Distribution		29,905		0.6
Steel		22,746		0.4
		1,658,968		30.4
> Consumer Goods & Services
Food		131,411		2.4
Other Consumer Services		122,291		2.3
Durables Goods		121,041		2.2
Retail		109,397		2.0
Casinos		93,787		1.7
Apparels		70,872		1.3
Consumer Goods Distribution		66,334		1.2
Nondurables		66,222		1.2
Entertainment		46,736		0.9
Travel		34,783		0.6
Leisure Products		33,816		0.6
Furniture & Textiles		28,189		0.5
Consumer Electronics		15,035		0.3
		939,914		17.2
> Information
Financial Processors		145,185		2.7
Computer Hardware & Related Equipment		98,422		1.8
Business Information & Marketing Services		89,239		1.6
Satellite Broadcasting		64,665		1.2
Cable Television		57,637		1.0
Internet Related		52,200		1.0
Semiconductors & Related Equipment		48,251		0.9
Television Broadcasting		39,960		0.7
Publishing		38,655		0.7
Business Software		37,517		0.7
Computer Services		27,310		0.5
Electronics Distribution		16,478		0.3
Instrumentation		10,818		0.2
		726,337		13.3

	Value (000)		Percent
> Energy & Minerals
Oil Services	$	339,105		6.2
Mining		175,227		3.2
Agricultural Commodities		58,180		1.1
Oil/Gas Producers		48,452		0.9
Refining/Marketing/Distribution		45,379		0.8
		666,343		12.2
> Other Industries
Transportation		236,316		4.3
Real Estate		120,269		2.2
Regulated Utilities		53,741		1.0
		410,326		7.5
> Finance
Banks		111,633		2.0
Money Management		68,418		1.3
Savings & Loans		64,598		1.2
Insurance		46,058		0.8
Closed End Funds		30,670		0.6
Other Finance Companies		19,457		0.4
		340,834		6.3
> Health Care
Medical Equipment		121,961		2.2
Services		87,404		1.6
Pharmaceuticals		44,231		0.8
Hospital Laboratory Supplies		9,581		0.2
Biotechnology Drug Delivery		9,401		0.2
		272,578		5.0
Total Equities:		5,015,300		91.9
Short-Term Obligations:		398,826		7.3
Total Investments:		5,414,126		99.2
Cash and Other Assets Less Liabilities:		44,604		0.8
Net Assets:	$	5,458,730		100.0	%

43

Columbia Acorn USA

Major Portfolio Changes in the Second Quarter (Unaudited)

	Number of Shares
	03/31/07		06/30/07
Additions
Information
AMIS Holdings		401,000		601,000
Blackbaud		0		177,906
Ciena		0		85,000
Microsemi		450,000		570,000
Polycom		305,000		475,000
Tellabs		2,285,000		2,585,000
TheStreet.com		0		507,897
Time Warner Telecom		1,386,000		1,486,000
Trimble Navigation		310,000		368,000
Consumer Goods & Services
Cavco Industries		225,000		287,900
Hansen Natural		0		90,000
NutriSystem		99,000		149,000
Pinnacle Entertainment		160,000		340,000
Pool		318,500		523,500
Industrial Goods & Services
American Commercial Lines		0		340,000
American Reprographics		116,000		196,000
Drew Industries		100,000		155,000
Genlyte Group		440,000		480,000
Interline Brands		150,000		225,000
Health Care
Array Biopharma		0		244,094
BioMarin		440,000		692,400
Collagenex Pharmaceuticals		200,000		300,000
Genitope		0		450,000
Medarex		0		204,400
Pharmacopeia		0		220,000
Seattle Genetics		0		251,400
Finance
MB Financial		0		105,000
Old Second Bancorp		0		75,000
Pacific Continental		170,000		308,000
Energy & Minerals
Carrizo Oil & Gas		0		120,000
Tesco		57,500		95,000
Tetra Technologies		0		71,000

	Number of Shares
	03/31/07		06/30/07
Sales
Information
Alltel		270,000		0
Gemstar-TV Guide International		2,580,000		0
JDA Software		524,000		0
Kronos		660,650		0
Supertex		220,000		189,296
TALX		100,000		0
THQ		60,000		0
Consumer Goods & Services
Carter's		600,200		300,000
Central Parking		296,700		0
HNI		106,000		45,800
ITT Educational Services		416,000		366,000
Industrial Goods & Services
K&F Industries		236,400		0
Health Care
The Medicines Company		400,000		0
United Surgical Partners		550,000		0
Viasys Healthcare		220,000		0
Finance
Anchor Bancorp Wisconsin		141,400		111,400
Energy & Minerals
St. Mary Land & Exploration		80,000		47,000

44

Columbia Acorn USA

Statement of Investments (Unaudited), June 30, 2007

Number of Shares			Value (000)
				Equities: 96.2%
Information 30.9%
		> Business Software 4.8%
	779,900	Avid Technology (a)	$	27,569
		Digital Nonlinear Editing Software & Systems
	355,000	Micros Systems (a)		19,312
		Information Systems for Restaurants & Hotels
	2,100,000	Novell (a)		16,359
		Directory, Operating System & Identity Management Software
	327,200	Parametric Technology (a)		7,071
		Engineering Software & Services
	230,400	Concur Technologies (a)		5,265
		Web Enabled Cost & Expense Management Software
	177,906	Blackbaud		3,928
		Software & Services for Non-profits
	250,000	Agile Software (a)		2,015
		Product Design Software
				81,519
		> Mobile Communications 4.5%
	1,005,000	Crown Castle International (a)		36,451
		Communications Towers
	506,000	American Tower (a)		21,252
		Communications Towers in USA & Mexico
	1,633,000	Dobson Communications (a)		18,143
		Rural & Small City Cellular Telephone Services
	88,000	Globalstar (a)		911
		Satellite Mobile Voice & Data Carrier
	75,000	Openwave Systems		469
		Internet Software for Mobile Devices
				77,226
		> Semiconductors & Related Equipment 3.8%
	1,298,490	Integrated Device Technology (a)		19,828
		Communications Semiconductors
	570,000	Microsemi (a)		13,651
		Analog/Mixed Signal Semiconductors
	1,050,000	Entegris (a)		12,474
		Semiconductor Wafer Shipping & Handling Products
	601,000	AMIS Holdings (a)		7,524
		Mixed-signal Semiconductors
	189,296	Supertex (a)		5,933
		Mixed-signal Semiconductors
	140,000	Littelfuse (a)		4,728
		Little Fuses
				64,138
		> Computer Hardware & Related Equipment 3.3%
	433,581	Nice Systems (a)		15,063
		Audio & Video Recording Solutions
	505,000	II-VI (a)		13,721
		Laser Components
	295,600	Amphenol		10,538
		Electronic Connectors
	130,000	Belden CDT		7,195
		Specialty Cable
	99,000	Zebra Technologies (a)		3,835
		Bar Code Printers

Number of Shares			Value (000)
	90,000	Netgear (a)	$	3,263
		Networking Products for Small Business & Home
	65,000	Intermec (a)		1,645
		Bar Code & Wireless LAN Systems
	40,000	Rogers (a)		1,480
		PCB Laminates & High-performance Foams
				56,740
		> Telecommunications Equipment 2.9%
	2,585,000	Tellabs (a)		27,815
		Telecommunications Equipment
	475,000	Polycom (a)		15,960
		Video Conferencing Equipment
	85,000	Ciena (a)		3,071
		Optical Transport & Broadband Access Equipment
	323,500	Symmetricom (a)		2,717
		Network Timing & Synchronization Devices
				49,563
		> Instrumentation 2.8%
	430,000	Flir Systems (a)		19,887
		Infrared Cameras
	140,000	Mettler Toledo (a)		13,371
		Laboratory Equipment
	368,000	Trimble Navigation (a)		11,850
		GPS-based Instruments
	60,000	FARO Technologies (a)		1,912
		Precision Measurement Equipment
				47,020
		> Telephone Services 2.0%
	1,486,000	Time Warner Telecom (a)		29,869
		Fiber Optic Telephone/Data Services
	340,000	Windstream		5,018
		Rural Telephone Franchises
				34,887
		> Internet Related 1.6%
	460,000	ValueClick (a)		13,552
		Internet Advertising
	980,000	CNET Networks (a)		8,026
		Internet Advertising on Niche Websites
	507,897	TheStreet.com		5,526
		Financial Information Website Publisher
				27,104
		> Business Information & Marketing Services 1.2%
	530,000	Ceridian (a)		18,550
		HR Services & Payment Processing
	98,300	Navigant Consulting (a)		1,824
		Financial Consulting Firm
				20,374
		> Financial Processors 0.9%
	393,280	Global Payments		15,594
		Credit Card Processor
				15,594
		> Computer Services 0.8%
	786,000	RCM Technologies (a)(b)		6,123
		Technology & Engineering Services
	1,005,500	AnswerThink (a)		3,640
		IT Integration & Best Practice Research

45

Columbia Acorn USA

Statement of Investments (Unaudited), continued

Number of Shares			Value (000)
		> Computer Services—continued
	95,000	SRA International (a)	$	2,399
		Government IT Services
	235,000	iGate (a)		1,885
		IT & Business Process Outsourcing Services
				14,047
		> TV Broadcasting 0.7%
	1,125,000	Entravision Communications (a)		11,734
		Spanish Language TV, Radio & Outdoor
				11,734
		> Radio 0.7%
	511,100	Salem Communications		5,668
		Radio Stations for Religious Programming
	705,500	Spanish Broadcasting System (a)		3,034
		Spanish Language Radio Stations
	300,000	Saga Communications (a)		2,940
		Radio Stations in Small- & Mid-sized Cities
				11,642
		> Television Programming 0.5%
	750,000	Lions Gate Entertainment (a)		8,273
		Film & TV Studio
				8,273
		> CATV 0.3%
	240,000	Discovery Holding (a)		5,518
		CATV Programming
				5,518
		> Gaming Equipment & Services 0.1%
	98,500	Shuffle Master (a)		1,635
		Card Shufflers & Casino Games
				1,635
Information: Total				527,014
Consumer Goods & Services 20.4%
		> Retail 4.4%
	398,000	Abercrombie & Fitch		29,046
		Teen Apparel Retailer
	418,000	Chico's FAS (a)		10,174
		Women's Specialty Retailer
	175,000	J Crew Group (a)		9,466
		Multi-channel Branded Retailer
	486,250	Christopher & Banks		8,339
		Women's Apparel Retailer
	224,500	AnnTaylor Stores (a)		7,952
		Women's Apparel Retailer
	95,000	Genesco (a)		4,969
		Multi-concept Branded Footwear Retailer
	200,000	Urban Outfitters (a)		4,806
		Apparel & Home Specialty Retailer
				74,752
		> Apparel 3.9%
	634,200	Oxford Industries		28,121
		Branded & Private Label Apparel
	885,200	True Religion Apparel (a)		17,996
		Premium Denim
	222,200	Coach (a)		10,530
		Designer & Retailer of Branded Leather Accessories

Number of Shares			Value (000)
	300,000	Carter's (a)	$	7,782
		Children's Branded Apparel
	90,000	Heelys (a)		2,327
		Wheeled Footwear
				66,756
		> Other Consumer Services 3.8%
	366,000	ITT Educational Services (a)		42,961
		Post-secondary Degree Programs
	149,000	NutriSystem (a)		10,406
		Weight Loss Programs
	310,000	Universal Technical Institute (a)		7,871
		Vocational Training
	60,000	Weight Watchers International		3,051
		Weight Loss Programs
				64,289
		> Other Durable Goods 1.8%
	2,078,300	Champion Enterprises (a)		20,430
		Manufactured Homes
	287,900	Cavco Industries (a)		10,802
		Higher End Manufactured Homes
				31,232
		> Leisure Products 1.8%
	301,300	International Speedway		15,882
		Largest Motorsports Racetrack Owner & Operator
	195,500	Speedway Motorsports		7,816
		Motorsport Racetrack Owner & Operator
	80,000	Thor Industries		3,611
		RV & Bus Manufacturer
	50,000	Polaris Industries		2,708
		Leisure Vehicles & Related Products
				30,017
		> Nondurables 1.6%
	531,400	Scotts Miracle-Gro		22,819
		Consumer Lawn & Garden Products
	108,000	Jarden (a)		4,645
		Branded Household Products
				27,464
		> Consumer Goods Distribution 1.2%
	523,500	Pool		20,432
		Distributor of Swimming Pool Supplies & Equipment
				20,432
		> Restaurants 0.8%
	337,500	Sonic (a)		7,465
		Quick Service Restaurant
	163,800	Red Robin Gourmet Burgers (a)		6,613
		Casual Dining Restaurant
				14,078
		> Casinos & Gaming 0.6%
	340,000	Pinnacle Entertainment (a)		9,571
		Regional Casino Operator
				9,571
		> Food & Beverage 0.2%
	90,000	Hansen Natural (a)		3,868
		Alternative Beverages
				3,868

46

Number of Shares			Value (000)
		> Furniture & Textiles 0.2%
	45,800	HNI	$	1,878
		Office Furniture & Fireplaces
	56,800	Knoll		1,272
		Office Furniture
				3,150
		> Travel 0.1%
	45,000	Vail Resorts (a)		2,739
		Ski Resort Operator & Developer
				2,739
Consumer Goods & Services: Total				348,348
Industrial Goods & Services 14.0%
		> Machinery 6.9%
	697,500	Ametek		27,677
		Aerospace/Industrial Instruments
	673,600	Pentair		25,980
		Pumps & Water Treatment
	650,300	ESCO Technologies		23,580
		Automatic Electric Meter Readers
	373,600	Nordson		18,740
		Dispensing Systems for Adhesives & Coatings
	319,800	Donaldson		11,369
		Industrial Air Filtration
	71,800	Toro		4,228
		Turf Maintenance Equipment
	132,000	Goodman Global (a)		2,933
		HVAC Equipment Manufacturer
	50,000	Kaydon		2,606
		Specialized Friction & Motion Control Products
				117,113
		> Electrical Components 2.2%
	480,000	Genlyte Group (a)		37,699
		Commercial Lighting Fixtures
				37,699
		> Other Industrial Services 1.5%
	340,000	American Commercial Lines (a)		8,857
		Operator of Inland Barges/Builder of Inland Barges
	350,000	Labor Ready (a)		8,089
		Temporary Manual Labor
	196,000	American Reprographics (a)		6,035
		Document Management & Logistics
	89,000	G&K Services		3,516
		Uniform Rental
				26,497
		> Construction 1.0%
	204,050	Florida Rock		13,773
		Aggregates & Concrete
	100,000	Simpson Manufacturing		3,374
		Wall Joint Maker
				17,147
		> Outsourcing Services 1.0%
	350,000	Quanta Services (a)		10,734
		Electrical & Telecom Construction Services

Number of Shares			Value (000)
	175,000	Administaff	$	5,861
		Professional Employer Organization
				16,595
		> Industrial Distribution 0.6%
	225,000	Interline Brands (a)		5,868
		Industrial Distribution
	70,000	Watsco		3,808
		HVAC Distribution
				9,676
		> Waste Management 0.5%
	280,875	Waste Connections (a)		8,494
		Solid Waste Management
				8,494
		> Industrial Materials & Specialty Chemicals 0.3%
	155,000	Drew Industries (a)		5,137
		RV & Manufactured Home Components
				5,137
Industrial Goods & Services: Total				238,358
Health Care 11.8%
		> Biotechnology & Drug Delivery 4.4%
	885,000	PDL BioPharma (a)		20,620
		Proprietary Monoclonal Antibodies
	692,400	BioMarin (a)		12,422
		Biotech Focused on Orphan Diseases
	580,000	Nektar Therapeutics (a)		5,504
		Drug Delivery Technologies
	3,690,300	Medicure (a)		4,982
	738,060	Medicure - Warrants (a)(c)		443
		Cardiovascular Biotech Company
	125,000	Myriad Genetics (a)		4,649
		Drugs/Diagnostics Hybrid
	1,135,000	Decode Genetics (a)		4,239
		Drugs for Heart Attack, Asthma & Vascular Disease
	204,400	Medarex (a)		2,921
		Humanized Antibodies
	650,000	La Jolla Pharmaceutical (a)		2,912
		Lupus Treatment
	244,094	Array Biopharma (a)		2,849
		Drugs for Cancer & Inflammatory Diseases
	248,600	Arena Pharmaceuticals (a)		2,732
		Novel Drug Targeting Technology
	500,000	IsoRay (a)		2,520
	100,000	IsoRay - Warrants (a)(c)		114
		Radiology Cancer Company
	251,400	Seattle Genetics (a)		2,466
		Antibody-based Therapies for Cancer
	271,590	Neurogen (a)		1,803
		Development-stage Biotech Focused on Neurology
	450,000	Genitope (a)		1,737
		Cancer Vaccine
	220,000	Pharmacopeia (a)		1,221
		Biotech Company with Broad Early-stage Pipeline
	273,500	Nuvelo (a)		744
		Development-stage Biotech Focused on Cardiovascular/Cancer

47

Columbia Acorn USA

Statement of Investments (Unaudited), continued

Number of Shares			Value (000)
		> Biotechnology & Drug Delivery—continued
	375,000	Locus Discovery, Series D, Pfd. (a)(c)	$	109
	193,288	Locus Discovery, Series B, Pfd. (a)(c)		56
		High Throughput Rational Drug Design
	18,181	Metabolex (a)(c)		64
		Diabetes Drug Development
				75,107
		> Medical Equipment & Devices 2.2%
	577,400	Edwards Lifesciences (a)		28,489
		Heart Valves
	105,000	Vital Signs		5,833
		Anesthesia, Respiratory & Sleep Products
	94,171	Advanced Medical Optics (a)		3,284
		Medical Devices for Eye Care
				37,606
		> Health Care Services 2.2%
	291,800	Lincare Holdings (a)		11,628
		Home Health Care Services
	210,000	LCA-Vision		9,925
		Lasik Surgery Centers
	470,000	PSS World Medical (a)		8,563
		Medical Supplies
	137,000	Charles River Laboratories (a)		7,072
		Pharmaceutical Research
				37,188
		> Pharmaceuticals 1.6%
	250,000	Medicis Pharmaceutical		7,635
		Specialty Pharmaceuticals-dermatology
	270,000	MGI Pharma (a)		6,040
		Specialty Pharmaceuticals for Oncology & Acute Care
	790,000	QLT (a)		5,846
		Specialty Pharmaceuticals for Ophthalmology & Dermatology
	300,000	Collagenex Pharmaceuticals (a)		3,720
		Specialty Pharmaceuticals-dermatology
	505,000	Barrier Therapeutics (a)		3,283
		Specialty Pharmaceuticals for Dermatology
				26,524
		> Medical Supplies 1.4%
	270,700	ICU Medical (a)		11,624
		Intravenous Therapy Products
	158,300	Techne (a)		9,056
		Cytokines, Antibodies & other Reagents for Life Science
	104,000	Arrow International		3,981
		Disposable Catheters
				24,661
Health Care: Total				201,086
Finance 8.8%
		> Finance Companies 3.2%
	1,121,500	AmeriCredit (a)		29,776
		Auto Lending
	482,900	World Acceptance (a)		20,634
		Personal Loans
	130,000	McGrath Rentcorp		4,380
		Temporary Space & IT Rentals
				54,790

Number of Shares			Value (000)
		> Insurance 2.7%
	714,500	HCC Insurance Holdings	$	23,872
		Specialty Insurance
	14,000	Markel (a)		6,784
		Specialty Insurance
	105,000	Philadelphia Consolidated Holding (a)		4,389
		Specialty Insurance
	87,000	Delphi Financial Group		3,638
		Group Employee Benefit Products & Services
	75,000	Endurance Specialty Holdings		3,003
		Commercial Lines Insurance/Reinsurance
	177,743	Eastern Insurance Holdings		2,824
		Workers Comp & Specialty Insurance
	91,000	United America Indemnity (a)		2,263
		Specialty Insurance
				46,773
		> Banks 2.5%
	212,756	Chittenden		7,436
		New England Bank
	239,500	TCF Financial		6,658
		Great Lakes Bank
	308,000	Pacific Continental		4,989
		Niche Pacific N.W. Bank
	145,000	Greene County Bancshares		4,533
		Tennessee Bank
	215,000	First Busey		4,298
		Illinois Bank
	105,000	MB Financial		3,648
		Chicago Bank
	94,000	Associated Banc-Corp		3,074
		Midwest Bank
	125,000	Lakeland Financial		2,659
		Indiana Bank
	114,777	Glacier Bancorp		2,336
		Mountain States Bank
	75,000	Old Second Bancorp		2,187
		Illinois Bank
	20,000	First Financial Bankshares		776
		West Texas Bank
	31,500	West Bancorporation		503
		Des Moines Commercial Bank
				43,097
		> Savings & Loans 0.4%
	168,000	People's United		2,979
		Connecticut Savings & Loan
	111,400	Anchor Bancorp Wisconsin		2,917
		Wisconsin Thrift
				5,896
Finance: Total				150,556
Energy & Minerals 7.8%
		> Oil Services 4.3%
	401,700	FMC Technologies (a)		31,823
		Oil & Gas Well Head Manufacturer

48

Number of Shares			Value (000)
		> Oil Services—continued
	367,000	Atwood Oceanics (a)	$	25,184
		Offshore Drilling Contractor
	355,000	Hanover Compressor (a)		8,467
		Natural Gas Compressor Rental & Fabrication
	95,000	Tesco (a)		2,997
		Developing New Well Drilling Technologies
	67,500	CARBO Ceramics		2,957
		Natural Gas Well Stimulants
	71,000	Tetra Technologies (a)		2,002
		U.S.-based Services Company with Life of Field Approach
	11,000	Key Energy Services (a)		204
		Well Workover Services
				73,634
		> Oil & Gas Producers 2.8%
	525,000	Quicksilver Resources (a)		23,404
		Natural Gas & Coal Seam Gas Producer
	208,400	Southwestern Energy (a)		9,274
		Oil & Gas Producer
	111,200	Equitable Resources		5,511
		Natural Gas Producer & Utility
	120,000	Carrizo Oil & Gas (a)		4,976
		Explores for Natural Gas & Crude Oil
	450,000	Vaalco Energy (a)		2,174
		Oil & Gas Producer
	47,000	St. Mary Land & Exploration		1,721
		Oil & Gas Producer
				47,060
		> Other Resources 0.5%
	218,000	Layne Christensen (a)		8,927
		Oil & Gas Production/Engineering & Construction/Contract Drilling
				8,927
		> Oil Refining, Marketing & Distribution 0.2%
	50,250	Oneok		2,533
		Natural Gas Distribution, Pipeline Processing & Trading
				2,533
Energy & Minerals: Total				132,154
Other Industries 2.5%
		> Real Estate 1.8%
	560,000	DiamondRock Hospitality		10,685
		Hotel Owner
	350,000	Highland Hospitality		6,720
		Hotel Owner
	77,500	Gaylord Entertainment (a)		4,157
		Convention Hotels
	100,000	Digital Realty Trust		3,768
		Technology-focused Office Buildings
	150,000	Kite Realty Group		2,853
		Community Shopping Centers
	90,000	American Campus Communities		2,546
		Student Housing
				30,729

Number of Shares or Principal Amount (000)			Value (000)
		> Transportation 0.5%
	524,720	Heartland Express	$	8,553
		Regional Trucker
				8,553
		> Regulated Utilities 0.2%
	97,500	Northeast Utilities		2,765
		Regulated Electric Utility
				2,765
Other Industries: Total				42,047
Total Equities: 96.2% (Cost: $1,132,404)				1,639,563
Short-Term Obligations 5.3%
$	8,700	Pasa Funding (d) 5.31% Due 7/03/07		8,697
	8,700	World Omni Vehicle Leasing (d) 5.30% Due 7/06/07		8,693
	8,600	Times Square Funding (d) 5.30% Due 7/02/07		8,599
	8,600	Transamerica Asset (d) 5.40% Due 7/02/07		8,599
	8,600	Morrigan TRR (d) 5.23% Due 7/05/07		8,595
	8,600	Morrigan TRR (d) 5.34% Due 7/09/07		8,590
	8,600	Natixis (d) 5.33% Due 7/10/07		8,588
	8,500	Abbey National 5.29% Due 7/02/07		8,499
	8,500	Erste Finance LLC (d) 5.32% Due 7/02/07		8,499
	8,500	Mica Funding LLC 5 (d) 5.32% Due 7/02/07		8,499
	4,154	Repurchase Agreement with Fixed Income Clearing Corp., dated 6/29/07, due 7/02/07 at 5.050%, collateralized by a U.S. Government Agency Obligation, maturing 7/18/11, market value $4,238 (repurchase proceeds $4,156)		4,154
		(Amortized Cost: $90,012)		90,012
Total Investments: 101.5% (Cost: $1,222,416)(e)				1,729,575
Cash and Other Assets Less Liabilities: (1.5)%				(26,037	)
Total Net Assets: 100%			$	1,703,538

49

Columbia Acorn USA

Statement of Investments (Unaudited), continued

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

(a)  Non-income producing security.

(b)  An affiliate may include any company in which the Fund owns five percent or more of its outstanding voting shares. Transactions in this affiliated company during the six months ended June 30, 2007, are as follows:

Affiliate	Balance of Shares Held 12/31/2006		Purchases/ Additions		Sales/ Reductions		Balance of Shares Held 6/30/2007		Value		Dividend
RCM Technologies		786,000		-		-		786,000	$	6,123	$	-

  The aggregate cost and value of this company at June 30, 2007, was $3,130 and $6,123, respectively. Investments in affiliate companies represented 0.4% of total net assets at June 30, 2007.

(c)  Denotes a restricted security, which is subject to restrictions on resale under federal securities laws. These securities, are valued in good faith by the Board of Trustees. At June 30, 2007, these securities had an aggregate value of $786 which represented 0.05% of total net assets.

  Additional information on these securities is as follows:

Security	Acquisition Dates	Shares		Cost		Value
Locus Discovery, Series D, Pfd.	9/5/01		375,000	$	1,500	$	109
Locus Discovery, Series B, Pfd.	2/8/07		193,288		56		56
Metabolex, Series F	5/11/00		18,181		2,000		64
IsoRay Warrants	3/21/07		100,000		-		114
Medicure Warrants	12/22/06		738,060		-		443
				$	3,556	$	786

(d)  Security exempt from registration under Section 4(2) of the Securities Act of 1933. These securities may only be resold in exempt transactions to qualified buyers. Private resales of these securities to qualified institutional buyers are also exempt from registration pursuant to Rule 144A under the Securities Act of 1933. At June 30, 2007, these securities amounted to $77,359, which represented 4.5% of net assets.

(e)  At June 30, 2007, for federal income tax purposes cost of investments was $1,222,416 and net unrealized appreciation was $507,159 consisting of gross unrealized appreciation of $551,801 and gross unrealized depreciation of $44,642.

50

Columbia Acorn International Select

Major Portfolio Changes in the Second Quarter (Unaudited)

	Number of Shares
	03/31/07		06/30/07
Additions
Europe
> Switzerland
Geberit		2,400		24,000
Kuehne & Nagel		49,000		70,000
Synthes		50,500		57,000
> Netherlands
Fugro		60,000		125,634
SBM Offshore		0		60,000
Stork		0		79,000
Wavin		0		44,936
> Ireland
CRH		140,000		146,737
United Drug		710,733		751,000
> United Kingdom
Informa Group		0		170,000
Intertek Testing		0		71,700
Smith & Nephew		441,000		535,000
> Austria
Zumtobel		172,500		189,500
> Greece
Intralot		60,000		130,000
Asia
> Japan
Hoya		140,000		153,000
Kansai Paint		280,000		540,000
Nintendo		21,500		29,700
> Hong Kong
Hong Kong Exchanges and Clearing		405,000		500,000
Other Countries
> United States
Atwood Oceanics		97,500		100,000

	Number of Shares
	03/31/07		06/30/07
Sales
Europe
> Ireland
Anglo Irish Bank		160,000		0
Bank of Ireland		240,000		65,000
C&C Group		100,800		24,700
Ryanair		85,000		0
> United Kingdom
Northern Rock		215,000		0
Paragon Group		310,000		0
> Spain
Red Electrica de Espana		90,000		85,000
> Italy
Banca Italease		30,000		0
Asia
> Japan
Daito Trust Construction		68,000		43,000
USS		40,000		32,000

51

Columbia Acorn International Select

Statement of Investments (Unaudited), June 30, 2007

Number of Shares			Value (000)
				Equities: 91.7%
Europe 51.4%
		> Switzerland 12.0%
	57,000	Synthes	$	6,841
		Products for Orthopedic Surgery
	70,000	Kuehne & Nagel		6,447
		Freight Forwarding/Logistics
	16,500	Nobel Biocare Holding		5,388
		Dental Implants & Ceramic Crowns
	24,000	Geberit		4,095
		Plumbing Supplies
	7,500	Swatch Group		2,130
		Watch & Electronics Manufacturer
	26,000	Schindler		1,724
		Elevator Manufacturer & Service Provider
				26,625
		> Netherlands 10.0%
	125,634	Fugro		7,973
		Oilfield Services
	79,000	Stork		5,128
		Industrial Services & Food Processing Equipment
	117,633	Aalberts Industries		3,230
		Flow Control & Heat Treatment
	60,000	SBM Offshore		2,287
		Builds & Leases Offshore Vessels to Process & Store Crude Oil
	34,723	USG People		1,631
		Temporary Staffing Services
	44,936	Wavin		1,081
		Largest European Plastic Pipe Systems Company
	23,100	Boskalis Westminster		919
		Dredging & Maritime Contractor
				22,249
		> Ireland 7.3%
	146,737	CRH		7,242
		Global Building Materials
	751,000	United Drug		4,101
		Irish Pharmaceutical Wholesaler & Outsourcer
	150,000	IAWS Group		3,142
		Baked Goods
	65,000	Bank of Ireland		1,317
		Irish Commercial Bank
	24,700	C&C Group		331
		Beverage Company
				16,133
		> United Kingdom 4.5%
	535,000	Smith & Nephew		6,620
		Medical Equipment & Supplies
	170,000	Informa Group		1,890
		Global Publisher & Event Organizer
	71,700	Intertek Testing		1,406
		Testing, Inspection, Certification Services
				9,916
		> Germany 3.5%
	40,000	Wincor Nixdorf		3,708
		Retail POS Systems & ATM Machines
	1,250	Porsche		2,225
		Specialty Automobile Manufacturer

Number of Shares			Value (000)
	17,000	Deutsche Boerse	$	1,926
		Trading, Clearing, Settlement Services for Financial Markets
				7,859
		> Austria 3.2%
	189,500	Zumtobel (a)		7,069
		Lighting Systems
				7,069
		> France 2.9%
	300,000	SES Global		6,466
		Satellite Broadcasting Services
				6,466
		> Sweden 2.7%
	318,000	Hexagon		6,098
		Measurement Equipment & Polymers
				6,098
		> Greece 1.9%
	130,000	Intralot		4,188
		Lottery & Gaming Systems & Services
				4,188
		> Spain 1.8%
	85,000	Red Electrica de Espana		3,983
		Spanish Power Grid
				3,983
		> Denmark 1.6%
	31,000	Novozymes		3,593
		Industrial Enzymes
				3,593
Europe: Total				114,179
Asia 28.4%
		> Japan 23.4%
	29,700	Nintendo		10,847
		Entertainment Software & Hardware
	6,700	Jupiter Telecommunications (a)		5,525
		Largest Cable Service Provider in Japan
	153,000	Hoya		5,064
		Opto-electrical Components & Eyeglass Lenses
	2,700	Kenedix		5,022
		Real Estate Investment Management
	77,000	Ibiden		4,958
		Electronic Parts & Ceramics
	160,000	Aeon Mall		4,908
		Suburban Shopping Mall Developer, Owner & Operator
	540,000	Kansai Paint		4,717
		Paint Producer in Japan, India, China & Southeast Asia
	143,700	JSR		3,461
		Films & Chemicals for LCD Screens & Electronics
	43,000	Daito Trust Construction		2,046
		Apartment Builder
	32,000	USS		2,037
		Used Car Auctioneer
	85,000	Ushio		1,883
		Industrial Light Sources

52

Number of Shares			Value (000)
		> Japan—continued
	138,000	Park24	$	1,385
		Parking Lot Operator
				51,853
		> Hong Kong 3.2%
	500,000	Hong Kong Exchanges and Clearing		7,074
		Hong Kong Equity & Derivatives Market Operator
				7,074
		> Singapore 1.8%
	630,000	Singapore Exchange		4,024
		Singapore Equity & Derivatives Market Operator
				4,024
Asia: Total				62,951
Other Countries 11.9%
		> Canada 4.8%
	90,000	Potash Corp. of Saskatchewan		7,017
		World's Largest Producer of Potash
	174,400	RONA (a)		3,643
		Leading Canadian Do-it-yourself Retailer
				10,660
		> South Africa 4.0%
	151,300	Impala Platinum Holdings		4,587
		Platinum Group Metals Mining & Refining
	165,000	Naspers		4,227
		Media & Education in Africa & Other Emerging Markets
				8,814
		> United States 3.1%
	100,000	Atwood Oceanics (a)		6,862
		Offshore Drilling Contractor
				6,862
Other Countries: Total				26,336
Total Equities: 91.7% (Cost: $156,119)				203,466

Principal Amount (000)			Value (000)
Short-Term Obligation 7.4%
$	16,495	Repurchase Agreement with Fixed Income Clearing Corp., dated 6/29/07, due 7/02/07 at 5.050%, collateralized by a U.S. Government Agency Obligation, maturing 7/18/11, market value $16,825 (repurchase proceeds $16,502)	$	16,495
		(Amortized Cost: $16,495)		16,495
Total Investments: 99.1% (Cost: $172,614)(b)(c)				219,961
Cash and Other Assets Less Liabilities: 0.9%				2,031
Total Net Assets: 100%			$	221,992

53

Columbia Acorn International Select Fund

Statement of Investments (Unaudited), continued

> Notes to Statement of Investments (in thousands)

(a)  Non-income producing security.

(b)  At June 30, 2007, for federal income tax purposes cost of investments was $172,614 and net unrealized appreciation was $47,347 consisting of gross unrealized appreciation of $51,104 and gross unrealized depreciation of $3,757.

(c)  On June 30, 2007, the Fund's total investments were denominated in currencies as follows:

Currency	Value		% of Net Assets
Euro	$	67,946		30.6	%
Japanese Yen		51,853		23.4
US Dollar		30,374		13.7
Swiss Franc		26,625		12.0
Other currencies less than 5% of total net assets		43,163		19.4
	$	219,961		99.1	%

54

Columbia Acorn International Select

Portfolio Diversification

At June 30, 2007, the Fund's portfolio investments as a percent of net assets was diversified as follows:

	Value (000)		Percent
> Industrial Goods & Services
Conglomerates	$	19,414		8.8	%
Construction		13,383		6.0
Specialty Chemicals		12,852		5.8
Other Industrial Services		9,577		4.3
Electrical Components		8,952		4.0
Outsourcing Services		1,631		0.7
		65,809		29.6
> Information
Financial Processors		13,024		5.9
Domestic Consumer Software		10,847		4.9
Satellite Broadcasting		6,466		2.9
Cable Television		5,525		2.5
Semiconductors & Related Equipment		5,064		2.3
Television Broadcasting		4,227		1.9
Computer Hardware & Related Equipment		3,708		1.7
Publishing		1,890		0.8
		50,751		22.9
> Energy & Minerals
Oil/Gas Producers		18,041		8.1
Mining		11,604		5.3
		29,645		13.4

	Value (000)		Percent
> Consumer Goods & Services
Retail	$	8,551		3.8
Durable Goods		4,355		2.0
Casinos		4,188		1.9
Food		3,473		1.6
Consumer Goods Distribution		2,037		0.9
Consumer Services		1,385		0.6
		23,989		10.8
> Health Care
Medical Equipment		18,849		8.5
Pharmaceuticals		4,101		1.8
		22,950		10.3
> Other Industries
Real Estate		5,022		2.3
Regulated Utilities		3,983		1.8
		9,005		4.1
> Finance
Banks		1,317		0.6
		1,317		0.6
Total Equities:		203,466		91.7
Short-Term Obligations:		16,495		7.4
Total Investments:		219,961		99.1
Cash and Other Assets Less Liabilities:		2,031		0.9
Net Assets:	$	221,992		100.0	%

55

Columbia Acorn Select

Major Portfolio Changes in the Second Quarter (Unaudited)

	Number of Shares
	03/31/07		06/30/07
Additions
Consumer Goods & Services
Chico's FAS		1,811,000		2,000,000
Hertz		1,750,000		2,000,000
Information
Globalstar		3,514,300		6,000,000
Liberty Global Series C		2,963,800		3,000,000
Sanmina-SCI		11,000,000		16,021,480
Tellabs		11,300,000		13,757,500
Energy & Minerals
Atwood Oceanics		400,000		500,000
Tetra Technologies		0		2,000,000
Finance
Conseco		5,800,000		6,550,000
Janus Capital Group		3,450,000		4,050,000
Montpelier Re		1,000,000		2,000,000
Industrial Goods & Services
American Commercial Lines		0		2,068,400
Worthington Industries		2,250,000		2,350,000
Other Industries
JB Hunt Transport Services		0		1,000,000

	Number of Shares
	03/31/07		06/30/07
Sales
Consumer Goods & Services
ITT Educational Services		1,475,000		1,300,000
Weight Watchers International		238,200		0
Finance
Nuveen Investments		975,000		0
Industrial Goods & Services
Quanta Services		3,030,000		2,700,000

56

Columbia Acorn Select

Statement of Investments (Unaudited), June 30, 2007

Number of Shares			Value (000)
				Equities: 89.7%
Consumer Goods & Services 26.5%
		> Retail 10.6%
	3,550,000	Safeway	$	120,806
		Supermarkets
	1,650,000	Abercrombie & Fitch		120,417
		Teen Apparel Retailer
	850,000	Costco Wholesale		49,742
		Warehouse Superstores
	2,000,000	Chico's FAS (a)		48,680
		Women's Specialty Retail
				339,645
		> Other Consumer Services 6.0%
	1,300,000	ITT Educational Services (a)		152,594
		Post-secondary Degree Programs
	1,500,000	Universal Technical Institute (a)(b)		38,085
		Vocational Training
				190,679
		> Travel 4.9%
	3,550,000	Expedia (a)		103,979
		Online Travel Services Company
	2,000,000	Hertz (a)		53,140
		Largest U.S. Rental Car Operator
				157,119
		> Leisure Products 2.7%
	800,000	Harley-Davidson		47,688
		Motorcycles & Related Merchandise
	750,000	International Speedway		39,533
		Largest Motorsports Racetrack Owner & Operator
				87,221
		> Apparel 2.3%
	1,550,000	Coach (a)		73,455
		Designer & Retailer of Branded Leather Accessories
				73,455
Consumer Goods & Services: Total				848,119
Information 25.6%
		> CATV 6.6%
	3,000,000	Liberty Global Series C (a)		117,900
	600,000	Liberty Global Series A (a)		24,624
		Cable TV Franchises Outside the USA
	3,000,000	Discovery Holding (a)		68,970
		CATV Programming
				211,494
		> Mobile Communications 4.9%
	2,300,000	American Tower (a)		96,600
		Communications Towers in USA & Mexico
	6,000,000	Globalstar (a)(b)		62,100
		Satellite Mobile Voice & Data Carrier
				158,700
		> Telecommunications Equipment 4.6%
	13,757,500	Tellabs (a)		148,031
		Telecommunications Equipment
				148,031

Number of Shares			Value (000)
		> Business Software 4.2%
	2,350,000	Avid Technology (a)(b)	$	83,072
		Digital Nonlinear Editing Software & Systems
	6,500,000	Novell (a)		50,635
		Directory, Operating System & Identity Management Software
				133,707
		> Internet Related 2.8%
	9,600,000	SkillSoft (a)(b)		89,184
		Web-based Learning Solutions (E-Learning)
				89,184
		> Contract Manufacturing 1.6%
	16,021,480	Sanmina-SCI (a)		50,147
		Electronic Manufacturing Services
				50,147
		> Semiconductors & Related Equipment 0.8%
	2,700,000	Canadian Solar (a)(b)		25,380
		Solar Cell & Module Manufacturer
				25,380
		> Computer Services 0.1%
	1,367,000	AnswerThink (a)		4,949
		IT Integration & Best Practice Research
				4,949
Information: Total				821,592
Energy & Minerals 14.1%
		> Mining 9.8%
	15,666,000	Uranium One (South Africa) (a)		199,566
		Uranium Mines in South Africa, Kazakhstan, Australia & the U.S.
	1,440,000	Potash Corp. of Saskatchewan (Canada)		112,277
		World's Largest Producer of Potash
				311,843
		> Oil Services 4.3%
	2,000,000	Tetra Technologies (a)		56,400
		U.S. Based Service Company with Life of Field Approach
	600,000	FMC Technologies (a)		47,532
		Oil & Gas Well Head Manufacturer
	500,000	Atwood Oceanics (a)		34,310
		Offshore Drilling Contractor
				138,242
Energy & Minerals: Total				450,085
Finance 12.0%
		> Insurance 7.1%
	6,550,000	Conseco (a)		136,829
		Life, Long-term Care & Medical Supplement Insurance
	112,000	Markel (a)		54,271
		Specialty Insurance
	2,000,000	Montpelier Re		37,080
		Commercial Lines Insurance/Reinsurance
				228,180

57

Columbia Acorn Select

Statement of Investments (Unaudited), continued

Number of Shares or Principal Amount (000)			Value (000)
		> Brokerage & Money Management 4.9%
	4,050,000	Janus Capital Group	$	112,752
		Manages Mutual Funds
	1,500,000	SEI Investments		43,560
		Mutual Fund Administration & Investment Management
				156,312
Finance: Total				384,492
Industrial Goods & Services 9.5%
		> Other Industrial Services 3.5%
	1,425,000	Expeditors International of Washington		58,852
		International Freight Forwarder
	2,068,400	American Commercial Lines (a)		53,882
		Operator of Inland Barges/Builder of Inland Barges
				112,734
		> Outsourcing Services 2.6%
	2,700,000	Quanta Services (a)		82,809
		Electrical & Telecom Construction Services
				82,809
		> Waste Management 1.8%
	1,500,000	Waste Management		58,575
		U.S. Garbage Collection & Disposal
				58,575
		> Steel 1.6%
	2,350,000	Worthington Industries		50,878
		Steel Processing & Manufactured Metal Products
				50,878
Industrial Goods & Services: Total				304,996
Health Care 1.1%
		> Health Care Services 1.1%
	910,000	Lincare Holdings (a)		36,263
		Home Health Care Services
				36,263
Health Care: Total				36,263
Other Industries 0.9%
		> Transportation 0.9%
	1,000,000	JB Hunt Transport Services		29,320
		Truck & Intermodal Carrier
				29,320
Other Industries: Total				29,320
Total Equities: 89.7% (Cost: $1,841,270)				2,874,867
Short-Term Obligations 10.0%
$	15,900	Natixis (c) 5.33% Due 7/11/07		15,876
	15,900	Giro Balanced Funding (c) 5.30% Due 7/20/07		15,856

Principal Amount (000)			Value (000)
$	15,900	Old Court Funding (c) 5.35% Due 7/26/07	$	15,841
	15,900	Keel Capital (c) 5.30% Due 7/27/07		15,839
	15,800	Ebury Finance Ltd. (c) 5.30% Due 7/5/07		15,791
	15,800	World Omni Vehicle Leasing (c) 5.30% Due 7/24/07		15,747
	15,700	Anglesea Funding (c) 5.29% Due 7/2/07		15,698
	15,700	Mainsail II Ltd. (c) 5.28% Due 7/3/07		15,695
	15,700	Austra (c) 5.28% Due 7/6/07		15,688
	15,700	White Point Funding (c) 5.32% Due 7/18/07		15,661
	15,700	Hannover Funding (c) 5.30% Due 7/19/07		15,658
	15,700	Coast Asset (c) 5.31% Due 7/23/07		15,649
	15,700	Liberty Street Funding (c) 5.33% Due 7/25/07		15,644
	15,600	Whistlejacket Capital (c) 5.29% Due 7/9/07		15,582
	15,500	Mica Funding LLC (c) 5.34% Due 7/13/07		15,472
	15,400	TSL USA (c) 5.30% Due 7/10/07		15,380
	15,400	La Fayette Asset Securitization LLC (c) 5.28% Due 7/11/07		15,377
	15,300	Bavaria (c) 5.31% Due 7/12/07		15,275
	15,000	Morrigan TRR (c) 5.34% Due 7/16/07		14,967
	15,000	Manhattan Asset Funding (c) 5.29% Due 7/17/07		14,965
	9,916	Repurchase Agreement with Fixed Income Clearing Corp., dated 6/29/07, due 7/2/07 at 5.050%, collateralized by a U.S. Government Agency Obligation, maturing 7/18/11, market value of $10,118 (repurchase proceeds $9,920)		9,916
		(Amortized Cost: $321,577)		321,577
Total Investments: 99.7% (Cost: $2,162,847)(d)				3,196,444
Cash and Other Assets Less Liabilities: 0.3%				9,698
Total Net Assets: 100%			$	3,206,142

58

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

(a)  Non-income producing security.

(b)  An affiliate may include any company in which the Fund owns five percent or more of its outstanding voting shares. Transactions in these affiliated companies during the six months ended June 30, 2007, are as follows:

Affiliates	Balance of Shares Held 12/31/06		Purchases/ Additions		Sales/ Reductions		Balance of Shares Held 6/30/07		Value		Dividend
Avid Technology		2,200,000		150,000		-		2,350,000	$	83,073	$	-
Canadian Solar		550,000		2,150,000		-		2,700,000		25,380		-
Globalstar		1,600,000		4,400,000		-		6,000,000		62,100		-
SkillSoft		9,600,000		-		-		9,600,000		89,184		-
Universal Technical Institute		1,350,000		150,000		-		1,500,000		38,085		-
UrAsia Energy (merged into Uranium One)*		30,050,000		2,000,000		32,050,000		-		-		-
TOTAL OF AFFILIATED TRANSACTIONS		45,350,000		8,850,000		32,050,000		22,150,000	$	297,822	$	-

*  At June 30, 2007, the Fund owned less than five percent of the company's outstanding voting shares.

  The aggregate cost and value of these companies at June 30, 2007, was $226,635 and $297,822, respectively. Investments in affiliate companies represented 9.3% of total net assets at June 30, 2007.

(c)  Security exempt from registration under Section 4(2) of the Securities Act of 1933. These securities may only be resold in exempt transactions to qualified buyers. Private resales of these securities to qualified instutional buyers are also exempt from registration pursuant to Rule 144A under the Securities Act of 1933. At June 30, 2007, these securities had an aggregate value of $311,661, which represented 9.7% of net assets.

(d)  At June 30, 2007 for federal income tax purposes cost of investments was $2,162,847 and net unrealized appreciation was $1,033,597 consisting of gross unrealized appreciation of $1,078,817 and gross unrealized depreciation of $45,220.

59

Columbia Thermostat Fund

Statement of Investments (Unaudited), June 30, 2007

Number of Shares or Principal Amount (000)			Value (000)
		> Bond Funds: 65.0%
	6,761,238	Columbia Intermediate Bond Fund, Class Z	$	58,688
	3,449,983	Columbia Federal Securities Fund, Class Z		35,190
	2,788,437	Columbia Conservative High Yield Fund, Class Z		23,088
Total Bond Funds (Cost: $118,839)				116,966
		> Stock Funds: 34.8%
	1,026,125	Columbia LargeCap Enhanced Core Fund, Class Z		15,659
	833,310	Columbia Dividend Income Fund, Class Z		12,591
	205,779	Columbia Acorn International, Class Z		9,429
	287,018	Columbia Acorn Fund, Class Z		9,403
	432,063	Columbia Marsico Growth Fund, Class Z		9,367
	203,678	Columbia Acorn Select, Class Z		6,285
Total Stock Funds (Cost: $52,596)				62,734
Short-Term Obligation: 0.4%
$	642	Repurchase Agreement with Fixed Income Clearing Corp., dated 6/29/07, due 7/02/07 at 5.050%, collateralized by a U.S. Government Agency Obligation, maturing 7/18/11 market value of $660 (repurchase proceeds $642)		642
		(Cost: $642)		642
Total Investments: 100.2% (Cost: $172,077)(a)				180,342
Cash and Other Assets Less Liabilities: (0.2)%				(313	)
Total Net Assets: 100%			$	180,029

> Notes to Statement of Investments (in thousands)

(a)  At June 30, 2007, for federal income tax purposes cost of investments was $172,077 and net unrealized appreciation was $8,265, consisting of gross unrealized appreciation of $10,274 and gross unrealized depreciation of $2,009.

60

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61

Columbia Acorn Family of Funds

Statements of Assets and Liabilities (Unaudited)

June 30, 2007	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	$	9,996,498	$	3,298,899		$	1,219,286	$	172,614		$	1,936,212		$	—
Affiliated investments, at cost (See Note 4)		2,646,859		102,622			3,130		—			226,635			172,077
Unaffiliated investments, at value	$	16,693,498	$	5,306,474		$	1,723,452	$	219,961		$	2,898,622		$	—
Affiliated investments, at value (See Note 4)		4,477,872		107,652			6,123		—			297,822			180,342
Cash		1,039		—	*		1,796		1			—	*		—	*
Foreign currency (cost: Columbia Acorn Fund $8,676; Columbia Acorn International $20,729; Columbia Acorn International Select $168)		8,694		20,858			—		168			—			—
Receivable for:
Investments sold		127,912		30,366			13,231		1,817			—			—
Fund shares sold		30,087		7,954			3,218		379			25,903			114
Dividends and interest		8,693		4,985			461		110			398			—	*
Foreign tax reclaims		606		1,183			—		59			—			—
Deferred Trustees' Compensation Investments		2,770		756			205		—			—			—
Expense Reimbursement due from Investment Adviser		—		—			—		—			—			50
Other assets		—		—			—		—			8			—
Total Assets		21,351,171		5,480,228			1,748,486		222,495			3,222,753			180,506
Liabilities:
Payable for:
Investments purchased		82,437		13,814			12,022		—			9,496			—
Fund shares redeemed		15,776		1,983			30,937		204			3,578			230
Management fee		11,164		3,337			1,230		166			2,020			15
Administration fee		695		174			57		7			102			6
12b-1 Service & Distribution fees		3,044		267			143		22			572			75
Reports to shareholders		1,568		350			154		36			331			65
Deferred Trustees' fees		2,770		756			205		26			183			22
Transfer agent fees		1,840		161			152		6			290			51
Trustees' fees		112		9			8		—	*		1			—	*
Audit fee		43		42			22		21			22			11
Custody fees		231		175			5		4			16			—	*
Deferred foreign capital gains tax payable		—		392			—		—			—			—
Other liabilities		213		38			13		11			—			2
Total Liabilities		119,893		21,498			44,948		503			16,611			477
Net Assets	$	21,231,278	$	5,458,730		$	1,703,538	$	221,992		$	3,206,142		$	180,029
Composition of Net Assets:
Paid in capital	$	11,951,843	$	3,203,553		$	1,134,839	$	166,910		$	2,138,388		$	165,454
Undistributed (overdistributed) net investment income (Accumulated net investment loss)		20,675		4,898			1,551		547			(15,544	)		2,903
Accumulated net realized gain		730,715		237,906			59,989		7,187			49,701			3,407
Net unrealized appreciation on:
Investments		8,528,013		2,012,605			507,159		47,347			1,033,597			8,265
Foreign capital gains tax		—		(392	)		—		—			—			—
Foreign currency translations		32		160			—		1			—			—
Net Assets	$	21,231,278	$	5,458,730		$	1,703,538	$	221,992		$	3,206,142		$	180,029
Net asset value per share – Class A (a)	$	31.94	$	45.59		$	30.37	$	30.82		$	30.35		$	12.80
(Net assets/shares)		($4,632,464/145,034)		($495,307/10,864)			($265,857/8,754)		($36,156/1,173)			($1,240,930/40,885)			($51,470/4,020)
Maximum offering price per share – Class A (b)	$	33.89	$	48.37		$	32.22	$	32.70		$	32.20		$	13.58
(Net asset value per share/front- end sales charge)		($31.94/0.9425)		($45.59/0.9425)			($30.37/0.9425)		($30.82/0.9425)			($30.35/0.9425)			($12.80/0.9425)
Net asset value and offering price per share – Class B (a)	$	30.47	$	44.69		$	29.02	$	29.74		$	29.03		$	12.84
(Net assets/shares)		($1,440,071/47,265)		($103,314/2,311)			($63,927/2,203)		($10,892/366)			($231,739/7,983)			($69,096/5,383)
Net asset value and offering price per share – Class C (a)	$	30.35	$	44.61		$	28.93	$	29.68		$	28.94		$	12.82
(Net assets/shares)		($1,450,101/47,779)		($135,340/3,035)			($57,674/1,993)		($9,778/329)			($222,201/7,679)			($25,991/2,028)
Net asset value and offering price per share – Class Z (c)	$	32.76	$	45.82		$	31.11	$	31.12		$	30.86		$	12.77
(Net assets/shares)		($13,708,642/418,519)		($4,724,769/103,107)			($1,316,080/42,302)		($165,166/5,308)			($1,511,272/48,965)			($33,472/2,622)

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

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

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

*  Rounds to less than $500.

See accompanying notes to financial statements.

62

Columbia Acorn Family of Funds

Statements of Operations (Unaudited)
For the Six Months Ended June 30, 2007

(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	$	96,782		$	55,989		$	8,785		$	1,827		$	4,355		$	—
Dividend income from affiliates (See Note 4)		17,334			2,028			—			—			—			—
Dividends from affiliated investment company shares (See Note 4)		—			—			—			—			—			3,618
Interest income		29,275			7,691			1,985			328			5,967			20
		143,391			65,708			10,770			2,155			10,322			3,638
Foreign taxes withheld		(1,937	)		(4,753	)		—	*		(123	)		(22	)		—
Total Investment Income		141,454			60,955			10,770			2,032			10,300			3,638
Expenses:
Management fee		64,166			18,550			7,160			915			10,678			92
Administration fee		3,856			931			320			37			513			35
12b-1 Service and Distribution fees:
Class A		5,431			495			328			37			1,354			68
Class B		5,328			366			241			39			839			264
Class C		6,984			583			282			41			977			134
Transfer agent fees:
Class A		1,498			158			91			13			408			46
Class B		1,069			90			58			11			203			63
Class C		688			60			30			6			116			24
Class Z		1,944			564			250			33			230			16
Custody fees		755			997			32			30			69			—	*
Trustees' fees		367			74			30			15			155			18
Registration & blue sky fees		129			82			54			40			56			32
Reports to shareholders		1,381			355			167			43			318			71
Chief compliance officer expenses (See Note 4)		244			58			23			6			32			6
Other expenses		480			137			59			31			70			25
Total expenses		94,320			23,500			9,125			1,297			16,018			894
Less custody fees paid indirectly		(69	)		(1	)		(14	)		—	*		(45	)		—	*
Less reimbursement of expenses by Investment Adviser		—			—			—			—			—			(187	)
Less reimbursement of expenses by Transfer Agent
Class A		(212	)		(16	)		(11	)		(1	)		(53	)		(4	)
Class B		(86	)		(7	)		(4	)		(1	)		(16	)		(5	)
Class C		(63	)		(6	)		(3	)		(1	)		(10	)		(2	)
Class Z		(376	)		(27	)		(48	)		(1	)		(21	)		—	*
Net Expenses		93,514			23,443			9,045			1,293			15,873			696
Net Investment Income (Loss)		47,940			37,512			1,725			739			(5,573	)		2,942
Net Realized and Unrealized Gain (Loss) on Portfolio Positions:
Net realized gain (loss) on:
Unaffiliated investments		602,100			240,610			62,278			15,823			49,991			—
Affiliated investments (See Note 4)		131,455			(20	)		—			—			—			4,235
Foreign currency transactions		(421	)		(847	)		—			(21	)		(18	)		—
Net realized gain on disposal of investments sold in error   (See Note 8)		4			—			—			—			—			—
Net realized gain		733,138			239,743			62,278			15,802			49,973			4,235
Net change in net unrealized appreciation (depreciation) on:
Unaffiliated investments		1,050,397			387,043			86,603			5,277			360,688			—
Affiliated investments (See Note 4)		339,838			5,031			—			—			—			405
Foreign currency translations		10			109			—			(2	)		69			—
Foreign capital gains tax		—			(392	)		—			—			—			—
Net change in unrealized appreciation (depreciation)		1,390,245			391,791			86,603			5,275			360,757			405
Net realized and unrealized gain		2,123,383			631,534			148,881			21,077			410,730			4,640
Net Increase in Net Assets resulting from Operations	$	2,171,323		$	669,046		$	150,606		$	21,816		$	405,157		$	7,582

*  Rounds to less than $500.

See accompanying notes to financial statements.

63

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)	2007			2006			2007			2006			2007			2006
Operations:
Net investment income (loss)	$	47,940		$	35,190		$	37,512		$	31,386		$	1,725		$	(3,110	)
Net realized gain on investments and foreign currency transactions		733,138			1,611,966			239,743			392,116			62,278			46,861
Net realized gain on affiliated investments and distributions from affiliated investment company shares		—			—			—			—			—			—
Net change in net unrealized appreciation (depreciation) on investments and foreign currency translations		1,390,245			712,218			391,791			645,701			86,603			64,360
Net change in net unrealized appreciation (depreciation) on affiliated investments		—			—			—			—			—			—
Net Increase from Operations		2,171,323			2,359,374			669,046			1,069,203			150,606			108,111
Distributions to Shareholders From:
Net investment income – Class A		—			(5,394	)		(61	)		(2,223	)		—			—
Net realized gain – Class A		(55,515	)		(313,513	)		(2,579	)		(26,545	)		(2,466	)		(5,181	)
Net investment income – Class B		—			—			—	*		(141	)		—			—
Net realized gain – Class B		(18,288	)		(114,707	)		(575	)		(8,646	)		(620	)		(1,487	)
Net investment income – Class C		—			—			—	*		(63	)		—			—
Net realized gain – Class C		(18,339	)		(109,093	)		(744	)		(8,998	)		(557	)		(1,223	)
Net investment income – Class Z		—			(48,532	)		(12,297	)		(44,617	)		—			—
Net realized gain – Class Z		(160,345	)		(916,129	)		(25,155	)		(342,510	)		(12,016	)		(25,202	)
Total Distributions to Shareholders		(252,487	)		(1,507,368	)		(41,411	)		(433,743	)		(15,659	)		(33,093	)
Share Transactions:
Subscriptions – Class A		615,959			1,078,213			175,970			176,101			51,185			113,090
Distributions reinvested – Class A		50,288			288,002			2,412			25,843			2,159			4,383
Redemptions – Class A		(513,833	)		(822,590	)		(48,303	)		(63,857	)		(53,863	)		(51,382	)
Net Increase (Decrease) – Class A		152,414			543,625			130,079			138,087			(519	)		66,091
Subscriptions – Class B		7,608			25,556			8,524			17,920			222			1,247
Distributions reinvested – Class B		16,730			104,566			526			8,016			566			1,351
Redemptions – Class B		(119,998	)		(212,371	)		(12,274	)		(20,296	)		(6,865	)		(14,036	)
Net Increase (Decrease) – Class B		(95,660	)		(82,249	)		(3,224	)		5,640			(6,077	)		(11,438	)
Subscriptions – Class C		65,011			166,508			29,598			50,734			2,005			17,895
Distributions reinvested – Class C		14,519			86,726			555			6,707			476			1,038
Redemptions – Class C		(102,057	)		(178,699	)		(9,005	)		(16,582	)		(4,411	)		(8,640	)
Net Increase (Decrease) – Class C		(22,527	)		74,535			21,148			40,859			(1,930	)		10,293
Subscriptions – Class Z		1,051,261			1,754,910			497,235			707,961			117,188			371,430
Distributions reinvested – Class Z		137,592			824,254			26,711			279,893			10,953			22,838
Redemptions – Class Z		(855,764	)		(1,413,279	)		(184,352	)		(357,229	)		(131,252	)		(175,498	)
Net Increase (Decrease) – Class Z		333,089			1,165,885			339,594			630,625			(3,111	)		218,770
Net Increase (Decrease) from Share Transactions		367,316			1,701,796			487,597			815,211			(11,637	)		283,716
Redemption Fees		—			—			103			147			—			—
Total Increase (Decrease) in Net Assets		2,286,152			2,553,802			1,115,335			1,450,818			123,310			358,734
Net Assets:
Beginning of period		18,945,126			16,391,324			4,343,395			2,892,577			1,580,228			1,221,494
End of period	$	21,231,278		$	18,945,126		$	5,458,730		$	4,343,395		$	1,703,538		$	1,580,228
Undistributed (Overdistributed) Net Investment Income or (Accumulated Net Investment Loss)	$	20,675		$	(27,265	)	$	4,898		$	(20,256	)	$	1,551		$	(174	)

*  Rounds to less than $500.

See accompanying notes to financial statements.

64

	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)	2007			2006			2007			2006			2007			2006
Operations:
Net investment income (loss)	$	739		$	361		$	(5,573	)	$	(11,032	)	$	2,942		$	6,358
Net realized gain on investments and foreign currency transactions		15,802			18,110			49,973			71,803			—			—
Net realized gain on affiliated investments and distributions from affiliated investment company shares		—			—			—			—			4,235			11,669
Net change in net unrealized appreciation (depreciation) on investments and foreign currency translations		5,275			20,770			360,757			287,875			—			—
Net change in net unrealized appreciation (depreciation) on affiliated investments		—			—			—			—			405			836
Net Increase from Operations		21,816			39,241			405,157			348,646			7,582			18,863
Distributions to Shareholders From:
Net investment income – Class A		(86	)		(2	)		—			(788	)		(125	)		(2,086	)
Net realized gain – Class A		—			—			(7,498	)		(20,503	)		(1,184	)		(3,300	)
Net investment income – Class B		—			—			—			—			—			(2,114	)
Net realized gain – Class B		—			—			(1,510	)		(4,991	)		(1,571	)		(3,980	)
Net investment income – Class C		—			—	*		—			—			—			(753	)
Net realized gain – Class C		—			—			(1,407	)		(3,972	)		(596	)		(1,496	)
Net investment income – Class Z		(782	)		(196	)		—			(1,614	)		(163	)		(1,223	)
Net realized gain – Class Z		—			—			(8,765	)		(19,241	)		(760	)		(1,585	)
Total Distributions to Shareholders		(868	)		(198	)		(19,180	)		(51,109	)		(4,399	)		(16,537	)
Share Transactions:
Subscriptions – Class A		13,035			10,850			233,175			210,532			3,216			6,298
Distributions reinvested – Class A		78			2			6,845			19,667			1,205			4,887
Redemptions – Class A		(2,741	)		(3,070	)		(97,602	)		(158,467	)		(11,969	)		(25,185	)
Net Increase (Decrease) – Class A		10,372			7,782			142,418			71,732			(7,548	)		(14,000	)
Subscriptions – Class B		1,382			2,223			2,301			4,782			1,993			3,578
Distributions reinvested – Class B		—			—			1,343			4,452			1,445			5,496
Redemptions – Class B		(1,392	)		(1,437	)		(18,505	)		(31,688	)		(7,964	)		(16,105	)
Net Increase (Decrease) – Class B		(10	)		786			(14,861	)		(22,454	)		(4,526	)		(7,031	)
Subscriptions – Class C		2,439			2,333			34,501			20,817			1,995			4,114
Distributions reinvested – Class C		—			—	*		1,110			3,230			529			1,960
Redemptions – Class C		(617	)		(924	)		(14,166	)		(22,947	)		(4,352	)		(7,323	)
Net Increase (Decrease) – Class C		1,822			1,409			21,445			1,100			(1,828	)		(1,249	)
Subscriptions – Class Z		30,453			34,878			499,307			258,516			3,072			5,698
Distributions reinvested – Class Z		341			99			6,448			14,293			855			2,633
Redemptions – Class Z		(10,851	)		(10,107	)		(72,303	)		(170,328	)		(1,708	)		(3,204	)
Net Increase (Decrease) – Class Z		19,943			24,870			433,452			102,481			2,219			5,127
Net Increase (Decrease) from Share Transactions		32,127			34,847			582,454			152,859			(11,683	)		(17,153	)
Redemption Fees		19			9			—			—			—			—
Total Increase (Decrease) in Net Assets		53,094			73,899			968,431			450,396			(8,500	)		(14,827	)
Net Assets:
Beginning of period		168,898			94,999			2,237,711			1,787,315			188,529			203,356
End of period	$	221,992		$	168,898		$	3,206,142		$	2,237,711		$	180,029		$	188,529
Undistributed (Overdistributed) Net Investment Income or (Accumulated Net Investment Loss)	$	547		$	676		$	(15,544	)	$	(9,971	)	$	2,903		$	249

65

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)	2007			2006			2007			2006			2007			2006
Subscriptions – Class A		20,066			37,015			4,120			4,588			1,756			4,113
Shares issued in reinvestment and capital gains – Class A		1,551			9,911			53			673			70			156
Less shares redeemed – Class A		(16,739	)		(28,264	)		(1,131	)		(1,723	)		(1,835	)		(1,877	)
Net Increase (Decrease) – Class A		4,878			18,662			3,042			3,538			(9	)		2,392
Subscriptions – Class B		260			909			203			482			8			47
Shares issued in reinvestment and capital gains – Class B		540			3,757			12			212			19			50
Less shares redeemed – Class B		(4,079	)		(7,576	)		(294	)		(553	)		(245	)		(533	)
Net Increase (Decrease) – Class B		(3,279	)		(2,910	)		(79	)		141			(218	)		(436	)
Subscriptions – Class C		2,223			5,931			709			1,356			72			678
Shares issued in reinvestment and capital gains – Class C		471			3,123			13			178			16			39
Less shares redeemed – Class C		(3,486	)		(6,396	)		(214	)		(455	)		(158	)		(328	)
Net Increase (Decrease) – Class C		(792	)		2,658			508			1,079			(70	)		389
Subscriptions – Class Z		33,477			58,774			11,650			18,601			3,909			13,228
Shares issued in reinvestment and capital gains – Class Z		4,138			27,709			588			7,251			345			796
Less shares redeemed – Class Z		(27,249	)		(47,499	)		(4,294	)		(9,331	)		(4,324	)		(6,302	)
Net Increase (Decrease) – Class Z		10,366			38,984			7,944			16,521			(70	)		7,722
Net Increase (Decrease) in Shares of Beneficial Interest		11,173			57,394			11,415			21,279			(367	)		10,067

*  Rounds to less than 500 shares.

See accompanying notes to financial statements.

66

	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)	2007			2006			2007			2006			2007			2006
Subscriptions – Class A		447			446			8,142			8,645			249			492
Shares issued in reinvestment and capital gains – Class A		3			—	*		222			777			93			390
Less shares redeemed – Class A		(94	)		(131	)		(3,412	)		(6,607	)		(931	)		(1,960	)
Net Increase (Decrease) – Class A		356			315			4,952			2,815			(589	)		(1,078	)
Subscriptions – Class B		49			97			85			207			154			279
Shares issued in reinvestment and capital gains – Class B		—	*		—	*		45			183			112			437
Less shares redeemed – Class B		(49	)		(64	)		(675	)		(1,373	)		(616	)		(1,253	)
Net Increase (Decrease) – Class B		—			33			(545	)		(983	)		(350	)		(537	)
Subscriptions – Class C		87			100			1,252			898			155			322
Shares issued in reinvestment and capital gains – Class C		—			—	*		38			133			40			156
Less shares redeemed – Class C		(22	)		(42	)		(518	)		(1,002	)		(336	)		(572	)
Net Increase (Decrease) – Class C		65			58			772			29			(141	)		(94	)
Subscriptions – Class Z		1,040			1,448			17,043			10,565			239			442
Shares issued in reinvestment and capital gains – Class Z		11			5			206			559			66			210
Less shares redeemed – Class Z		(371	)		(427	)		(2,490	)		(7,111	)		(131	)		(248	)
Net Increase (Decrease) – Class Z		680			1,026			14,759			4,013			174			404
Net Increase (Decrease) in Shares of Beneficial Interest		1,101			1,432			19,938			5,874			(906	)		(1,305	)

67

Columbia Acorn Family of Funds

Financial Highlights

Columbia Acorn Fund

Class Z	(Unaudited) Six months ended June 30,			Year ended December 31,
Selected data for a share outstanding throughout each period	2007			2006			2005			2004			2003			2002
Net Asset Value, Beginning of Period	$	29.71		$	28.17		$	26.45		$	22.56		$	15.50		$	17.88
Income from Investment Operations
Net investment income (a)		0.11			0.13			0.15			0.04			0.03			0.02
Net realized and unrealized gain (loss)		3.33			3.92			3.28			4.78			7.05			(2.40	)
Total from Investment Operations		3.44			4.05			3.43			4.82			7.08			(2.38	)
Less Distributions Declared to Shareholders
From net investment income		—			(0.13	)		(0.15	)		(0.02	)		—			—
From net realized gains		(0.39	)		(2.38	)		(1.56	)		(0.91	)		(0.02	)		—
Total Distributions Declared to Shareholders		(0.39	)		(2.51	)		(1.71	)		(0.93	)		(0.02	)		—
Net Asset Value, End of Period	$	32.76		$	29.71		$	28.17		$	26.45		$	22.56		$	15.50
Total Return (b)		11.55	%(c)(d)		14.45	%(c)		13.11	%(c)		21.51	%(c)		45.68	%		(13.31	)%
Ratios to Average Net Assets/Supplemental Data
Net expenses (e)		0.73	%(f)		0.74	%		0.74	%		0.81	%		0.80	%		0.82	%
Net investment income (e)		0.67	%(f)		0.45	%		0.57	%		0.18	%		0.17	%		0.15	%
Waiver/reimbursement		0.01	%(f)		0.01	%		0.02	%		0.02	%		—			—
Portfolio turnover rate		10	%(d)		22	%		16	%		20	%		10	%		13	%
Net assets at end of period (in millions)	$	13,709		$	12,128		$	10,399		$	8,689		$	7,065		$	4,022

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

(d)  Not annualized.

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

(f)  Annualized.

Columbia Acorn International

Class Z	(Unaudited) Six months ended June 30,			Year ended December 31,
Selected data for a share outstanding throughout each period	2007			2006			2005			2004			2003			2002
Net Asset Value, Beginning of Period	$	40.31		$	33.44		$	29.03		$	22.66		$	15.40		$	18.47
Income from Investment Operations
Net investment income (a)		0.34			0.35			0.34			0.25			0.21			0.14
Net realized and unrealized gain (loss)		5.54			10.94			5.87			6.37			7.13			(3.10	)
Total from Investment Operations		5.88			11.29			6.21			6.62			7.34			(2.96	)
Less Distributions Declared to Shareholders
From net investment income		(0.12	)		(0.51	)		(0.72	)		(0.25	)		(0.08	)		(0.11	)
From net realized gains		(0.25	)		(3.91	)		(1.08	)		—			—			—
Total Distributions Declared to Shareholders		(0.37	)		(4.42	)		(1.80	)		(0.25	)		(0.08	)		(0.11	)
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)		—			—
Net Asset Value, End of Period	$	45.82		$	40.31		$	33.44		$	29.03		$	22.66		$	15.40
Total Return (c)		14.59	%(d)(e)		34.53	%(d)		21.81	%(d)		29.47	%(d)		47.80	%		(16.10	)%
Ratios to Average Net Assets/Supplemental Data
Net expenses (f)		0.90	%(g)		0.94	%		0.99	%		1.08	%		1.05	%		1.06	%
Net investment income (f)		1.61	%(g)		0.92	%		1.09	%		1.01	%		1.19	%		0.80	%
Waiver/reimbursement		0.00	%(g)(h)		0.01	%		0.02	%		0.02	%		—			—
Portfolio turnover rate		16	%(e)		31	%		27	%		40	%		40	%		52	%
Net assets at end of period (in millions)	$	4,725		$	3,836		$	2,629		$	1,919		$	1,563		$	1,241

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

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

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

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

(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 0.01%.

See accompanying notes to financial statements.

68

Columbia Acorn USA

Class Z	(Unaudited) Six months ended June 30,			Year ended December 31,
Selected data for a share outstanding throughout each period	2007			2006			2005			2004			2003			2002
Net Asset Value, Beginning of Period	$	28.66		$	27.03		$	25.20		$	21.01		$	14.28		$	17.52
Income from Investment Operations
Net investment income (loss) (a)		0.05			(0.02	)		0.07			(0.15	)		(0.13	)		(0.10	)
Net realized and unrealized gain (loss)		2.68			2.26			3.18			4.48			6.86			(3.14	)
Total from Investment Operations		2.73			2.24			3.25			4.33			6.73			(3.24	)
Less Distributions Declared to Shareholders
From net investment income		—			—			(0.05	)		—			—			—
From net realized gains		(0.28	)		(0.61	)		(1.37	)		(0.14	)		—			—
Total Distributions Declared to Shareholders		(0.28	)		(0.61	)		(1.42	)		(0.14	)		—			—
Net Asset Value, End of Period	$	31.11		$	28.66		$	27.03		$	25.20		$	21.01		$	14.28
Total Return (b)		9.50	%(c)(d)		8.28	%(c)		12.98	%(c)		20.62	%(c)		47.13	%		(18.49	)%
Ratios to Average Net Assets/Supplemental Data
Net expenses (e)		0.97	%(f)		0.98	%		1.01	%		1.09	%		1.11	%		1.17	%
Net investment income (loss) (e)		0.31	%(f)		(0.07	)%		0.28	%		(0.66	)%		(0.72	)%		(0.64	)%
Waiver/reimbursement		0.01	%(f)		0.01	%		0.01	%		0.02	%		—			—
Portfolio turnover rate		9	%(d)		13	%		13	%		18	%		7	%		31	%
Net assets at end of period (in millions)	$	1,316		$	1,214		$	937		$	646		$	502		$	235

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

(d)  Not annualized.

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

(f)  Annualized.

Columbia Acorn International Select

Class Z	(Unaudited) Six months ended June 30,			Year ended December 31,
Selected data for a share outstanding throughout each period	2007			2006			2005			2004			2003			2002
Net Asset Value, Beginning of Period	$	27.97		$	20.57		$	18.02		$	14.58		$	10.29		$	12.09
Income from Investment Operations
Net investment income (a)		0.13			0.10			0.13			0.04			0.06			0.03
Net realized and unrealized gain (loss)		3.17			7.35			2.70			3.47			4.24			(1.83	)
Total from Investment Operations		3.30			7.45			2.83			3.51			4.30			(1.80	)
Less Distributions Declared to Shareholders
From net investment income		(0.15	)		(0.05	)		(0.28	)		(0.07	)		(0.01	)		—
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)		—			—
Net Asset Value, End of Period	$	31.12		$	27.97		$	20.57		$	18.02		$	14.58		$	10.29
Total Return (c)		11.80	%(e)(d)		36.27	%(d)		15.98	%(d)		24.14	%(d)		41.79	%		(14.89	)%
Ratios to Average Net Assets/Supplemental Data
Net expenses (f)		1.19	%(g)		1.27	%		1.45	%		1.45	%		1.45	%		1.45	%
Net investment income (f)		0.89	%(g)		0.44	%		0.72	%		0.27	%		0.56	%		0.26	%
Waiver/reimbursement		0.00	%(g)(h)		0.01	%		0.04	%		0.29	%		0.42	%		0.33	%
Portfolio turnover rate		31	%(e)		47	%		39	%		73	%		69	%		102	%
Net assets at end of period (in millions)	$	165		$	129		$	74		$	46		$	34		$	26

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

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

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

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

(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 0.01%.

See accompanying notes to financial statements.

69

Columbia Acorn Family of Funds

Financial Highlights, continued

Columbia Acorn Select

Class Z	(Unaudited) Six months ended June 30,			Year ended December 31,
Selected data for a share outstanding throughout each period	2007			2006			2005			2004			2003			2002
Net Asset Value, Beginning of Period	$	26.59		$	22.77		$	21.13		$	18.20		$	14.04		$	15.23
Income from Investment Operations
Net investment loss (a)		(0.02	)		(0.06	)		(0.03	)		(0.10	)		(0.10	)		(0.10	)
Net realized and unrealized gain (loss)		4.48			4.51			2.35			3.47			4.39			(1.09	)
Total from Investment Operations		4.46			4.45			2.32			3.37			4.29			(1.19	)
Less Distributions Declared to Shareholders
From net investment income		—			(0.04	)		—			—			—			—
From net realized gains		(0.19	)		(0.59	)		(0.68	)		(0.44	)		(0.13	)		—
Total Distributions Declared to Shareholders		(0.19	)		(0.63	)		(0.68	)		(0.44	)		(0.13	)		—
Net Asset Value, End of Period	$	30.86		$	26.59		$	22.77		$	21.13		$	18.20		$	14.04
Total Return (b)		16.76	%(c)(d)		19.68	%(c)		11.08	%(c)		18.58	%(c)		30.61	%		(7.81	)%(c)
Ratios to Average Net Assets/Supplemental Data
Net expenses (e)		0.92	%(f)		0.96	%		0.99	%		1.13	%		1.12	%		1.26	%
Net investment loss (e)		(0.14	)%(f)		(0.26	)%		(0.16	)%		(0.52	)%		(0.63	)%		(0.67	)%
Waiver/reimbursement		0.00	%(f)(g)		0.02	%		0.03	%		0.02	%		—			0.01	%
Portfolio turnover rate		7	%(d)		21	%		19	%		34	%		16	%		40	%
Net assets at end of period (in millions)	$	1,511		$	909		$	688		$	445		$	294		$	93

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

(d)  Not annualized.

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

(f)  Annualized.

(g)  Rounds to less than 0.01%.

Columbia Thermostat Fund

Class Z	(Unaudited) Six months ended June 30,			Year ended December 31,												Inception September 25, 2002 through December 31,
Selected data for a share outstanding throughout each period	2007			2006			2005			2004			2003			2002
Net Asset Value, Beginning of Period	$	12.57		$	12.50			13.12		$	12.31		$	10.41		$	10.00
Income from Investment Operations
Net investment income (a)		0.24			0.49			0.43			0.31			0.19			0.04
Net realized and unrealized gain		0.32			0.84			0.28			0.82			1.87			0.37
Total from Investment Operations		0.56			1.33			0.71			1.13			2.06			0.41
Less Distributions Declared to Shareholders
From net investment income		(0.06	)		(0.54	)		(0.42	)		(0.29	)		(0.16	)		—
From net realized gains		(0.30	)		(0.72	)		(0.91	)		(0.03	)		(0.00	)(b)		—
Total Distributions Declared to Shareholders		(0.36	)		(1.26	)		(1.33	)		(0.32	)		(0.16	)		—
Net Asset Value, End of Period	$	12.77		$	12.57		$	12.50		$	13.12		$	12.31		$	10.41
Total Return (c)(d)		4.43	%(e)		10.86	%		5.50	%		9.17	%		19.79	%		4.10	%(e)
Ratios to Average Net Assets/Supplemental Data
Net expenses (f)		0.25	%(g)(h)		0.25	%(g)		0.25	%(g)		0.25	%(g)		0.38	%(g)		0.62	%(h)(i)
Net investment income		3.74	%(g)(h)		3.84	%(g)		3.28	%(g)		2.48	%(g)		1.64	%(g)		1.41	%(h)(i)
Waiver/reimbursement		0.15	%(h)		0.13	%		0.11	%		0.21	%		0.88	%		19.94	%(h)
Portfolio turnover rate		39	%(e)		66	%		96	%		67	%		61	%		11	%(e)
Net assets at end of period (in millions)	$	33		$	31		$	26		$	21		$	14		$	4

(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.

(d)  Had the Investment Adviser and/or Transfer Agent not 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.

(i)  In accordance with a requirement of the Securities and Exchange Commission, the ratios reflect total expenses prior to the reduction of custody fees for cash balances the Fund maintains with the custodian ("custody fees paid indirectly"). The ratios of expenses to average daily net assets and net investment income to average daily net assets net of custody fees paid indirectly would have been 0.60% and 1.43%, respectively for the period ended December 31, 2002.

See accompanying notes to financial statements.

70

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, excluding Columbia Thermostat Fund, is to seek long-term growth of capital. The investment objective of Columbia Thermostat Fund is to provide long-term total return. The Fund pursues its investment objective by investing in shares of other mutual funds. As a "fund of funds" under normal circumstances, the Fund allocates at least 95% of its net assets among a selected group of stock and bond mutual funds ("portfolio funds") according to the current level of the Standard & Poor's 500 Stock Index in relation to predetermined ranges set by the Fund's investment 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.

The Funds may issue an unlimited number of shares. The Funds currently offer four classes of shares: Class A, Class B, Class C and Class Z.

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

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

Class C shares are subject to a CDSC on redemptions made within one year after purchase.

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

Columbia Acorn International and Columbia Acorn International Select impose a 2% redemption fee on Class A, Class B, Class C and Class Z shares that are redeemed within 60 days or less. See "Fund Policy on Trading of Fund Shares" as disclosed in the Funds' prospectuses for more information.

The financial highlights for Class A, Class B and Class C shares are presented in a separate semiannual 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 each class bears certain expenses unique to that class such as distribution services, transfer agent, and certain other class specific expenses. Differences in class expenses may result in payment of different dividend distributions for each class. All the share classes of the Trust have equal rights with respect to voting subject to Fund or class specific matters.

2.  Significant Accounting Policies

>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 accordance with procedures established by the Board of Trustees. With respect to Columbia Thermostat Fund, investments in portfolio funds are valued at their net asset value as reported by the underlying funds. A security traded on a securities exchange or in the 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. A security for which there is no reported sale on the valuation date is valued at the latest bid quotation. A short-term debt obligation having a maturity of 60 days or less from the valuation date is valued at amortized cost, which approximate fair value. A security for which a market quotation is not readily available and any other assets are valued in accordance with procedures established by the Board of Trustees. The Trust has retained an independent statistical fair value pricing service 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 a "fair value," that value may be different from the last quoted market price for the security.

In September 2006, Statement of Financial Accounting Standards No. 157, Fair Value Measurements ("SFAS 157"), was issued. SFAS 157 is effective for fiscal years beginning after November 15, 2007. SFAS 157 defines fair value, establishes a framework for measuring fair value and expands disclosures about fair value measurements. Management is evaluating the

71

Columbia Acorn Family of Funds

Notes to Financial Statements (Unaudited), continued

impact the application of SFAS 157 will have on the Funds' financial statement disclosures.

>Repurchase agreements

The Funds may engage in repurchase agreement transactions. The Funds, through their custodians, receive delivery of underlying securities collateralizing repurchase agreements. The Funds' investment adviser determines that the value of the underlying securities is at all times at least equal to the resale price. In the event of default or bankruptcy by the other party 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 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.

>Security transactions and investment income

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

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

The Funds estimate components 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. The Funds will not incur any registration costs upon such resale.

>Use of estimates

The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America ("GAAP") requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results may differ from those estimates.

>Fund share valuation

Fund shares are sold and redeemed on a continuing basis at net asset value subject to any applicable sales charge. Net asset value per share is determined daily as of the close of trading on the New York Stock Exchange ("NYSE") on each day the NYSE is open for trading. All income, expenses (other than the Class A, Class B and Class C shares Rule 12b-1 service and distribution fees and Class A, Class B, Class C and Class Z shares transfer agent fees) and realized and unrealized gains (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. Redemption fees are accounted for as an addition to paid in capital for purposes of determining the net asset value of each class.

>Custody fees/credits

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

>Federal income taxes

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

72

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-date.

>Indemnification

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

3.  Federal Tax Information

The tax character of distributions paid during the year ended December 31, 2006 was as follows:

	Ordinary Income*		Long-Term Capital Gains
(in thousands)
Columbia Acorn Fund	$	102,167	$	1,405,201
Columbia Acorn International		47,043		386,698
Columbia Acorn USA		—		33,093
Columbia Acorn International Select		198		—
Columbia Acorn Select		9,493		41,617
Columbia Thermostat Fund		7,031		9,506

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

The following capital loss carryforwards, determined as of December 31, 2006, 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	Columbia Acorn USA			Columbia Acorn International Select
(in thousands)
2009	$	1,517	*	$	—
2010		506			6,126
2011		—			2,488
TOTAL	$	2,023		$	8,614

*Of these carryforwards, $2,023 (expiring in 2009 and 2010) remains from Columbia Acorn USA's merger with Stein Roe Small Company Growth Fund on 7/26/2002. Utilization of Stein Roe Small Company Growth Fund's losses could be subject to limitations imposed by the Internal Revenue Code.

The following capital loss carryforwards were utilized during the year ended December 31, 2006.

(in thousands)
Columbia Acorn USA	$	506
Columbia Acorn International Select		16,995

The Funds adopted Financial Accounting Standards Board ("FASB") Interpretation No. 48, Accounting for Uncertainty in Income Taxes – an Interpretation of FASB Statement No. 109 ("FIN 48") effective June 29, 2007. FIN 48 requires management to determine whether a tax position of a Fund 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 in the technical merits of the position. The tax benefit to be recognized is measured as the largest amount of benefit that is greater than fifty percent likely of being realized upon ultimate settlement. FIN 48 must be applied to all existing tax positions upon initial adoption and the cumulative effect, if any, is to be reported as an adjustment to net assets. Management has evaluated the known implications of FIN 48 on its computation of net assets for the Funds. As a result of this evaluation, management believes that FIN 48 will not have any effect on the Fund's financial statements. However, management's conclusions regarding FIN 48 may be subject to review and adjustment at a later date based on factors including, but not limited to, further guidance expected from the FASB, new tax laws, regulations, and administrative interpretations (including relevant court decisions).

4.  Transactions with Affiliates

Columbia WAM furnishes continuing investment supervision to the Funds and is responsible for the overall management of the Funds' business affairs.

Effective August 1, 2007, under the Funds' investment advisory agreement, fees are accrued daily based on the Funds' average daily net assets and paid monthly to Columbia WAM at the annual rates shown in the table below for Columbia Acorn International Select:

Columbia Acorn International Select

Average Daily Net Assets		Annual Fee Rate
	Up to $500 million		0.940	%
	$500 million and over		0.900	%

For all of the Funds, and prior to August 1, 2007, for Columbia Acorn International Select, for the period covered by this report as provided under the Funds' investment advisory agreement, fees were accrued daily based on the Funds' average daily net assets and paid monthly to Columbia WAM at the annual rates shown in the table below for each Fund.

73

Columbia Acorn Family of Funds

Notes to Financial Statements (Unaudited), continued

Columbia Acorn Fund

Average Daily Net Assets	Annual Fee Rate
Up to $700 million		0.740	%
$700 million to $2 billion		0.690	%
$2 billion to $6 billion		0.640	%
$6 billion and over		0.630	%

Columbia Acorn International

Average Daily Net Assets	Annual Fee Rate
Up to $100 million		1.190	%
$100 million to $500 million		0.940	%
$500 million and over		0.740	%

Columbia Acorn USA

Average Daily Net Assets	Annual Fee Rate
Up to $200 million		0.940	%
$200 million to $500 million		0.890	%
$500 million to $2 billion		0.840	%
$2 billion to $3 billion		0.800	%
$3 billion and over		0.700	%

Columbia Acorn Select

Average Daily Net Assets	Annual Fee Rate
Up to $700 million		0.850	%
$700 million to $2 billion		0.800	%
$2 billion to $3 billion		0.750	%
$3 billion and over		0.700	%

Columbia Acorn International Select

All Average Daily Net Assets 0.940 %

Columbia Thermostat Fund

All Average Daily Net Assets 0.100 %

For the six months ended June 30, 2007, the Funds' annualized 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	0.80	%
Columbia Thermostat Fund	0.10	%

>Expense limit

Columbia WAM has voluntarily agreed to reimburse the ordinary operating expenses (exclusive of interest, taxes and extraordinary expenses, if any) exceeding 1.45% of the average daily net assets for Columbia Acorn International Select Class Z shares and 1.35% of the average daily net assets for Columbia Acorn Select Class Z shares. This arrangement may be modified or terminated by either the Funds or Columbia WAM on 30 days notice.

Columbia WAM has agreed to contractually reimburse the ordinary operating expenses (exclusive of interest and fees on borrowings and expenses associated with the Fund's investment in other investment companies) exceeding 0.25% of the average daily net assets of Columbia Thermostat Fund's Class Z shares through April 30, 2008.

Expenses reimbursed by Columbia WAM for Columbia Thermostat Fund for the six months ended June 30, 2007, were $186,952.

Columbia WAM 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		0.05	%
$8 billion to $16 billion		0.04	%
$16 billion and over		0.03	%

For the six months ended June 30, 2007 each Fund's annualized effective administration fee rate was 0.04%. Columbia WAM has delegated to Columbia Management Advisors, LLC, an indirect, wholly owned subsidiary of BOA, responsibility to provide certain administrative services to the Funds.

Columbia Management Distributors, Inc. ("CMDI"), a wholly owned subsidiary of BOA, is the Funds' principal underwriter and receives no compensation on the sale of Class Z shares.

Each Fund has adopted a Rule 12b-1 plan which requires it to pay CMDI a service and distribution fee on the net assets attributable to Class A, Class B and Class C shares.

Columbia Management Services, Inc. (the "Transfer Agent"), a wholly owned subsidiary of BOA, provides shareholder services to the Funds and has contracted with Boston Financial Data Services ("BFDS") to serve as sub-transfer agent. For such services, the Transfer Agent receives a fee, paid monthly, at the annual rate of $17.00 per open account. The Transfer Agent also receives reimbursement for certain out-of-pocket expenses and sub-transfer agency expenses. During the period January 1, 2007, through March 31, 2007, a portion of these fees were contractually waived.

74

Expenses waived by the Transfer Agent for the six months ended June 30, 2007, were as follows:

(in thousands)
Columbia Acorn Fund	$	737
Columbia Acorn International		56
Columbia Acorn USA		66
Columbia Acorn International Select		4
Columbia Acorn Select		100
Columbia Thermostat Fund		11

Certain officers and trustees of the Trust are also officers of Columbia WAM. The Trust makes no direct payments to its officers and trustees who are affiliated with Columbia WAM. For those trustees not affiliated with Columbia WAM, fees and expenses paid by the Funds for the six months ended June 30, 2007, were as follows:

(in thousands)
Columbia Acorn Fund	$	367
Columbia Acorn International		74
Columbia Acorn USA		30
Columbia Acorn International Select		15
Columbia Acorn Select		155
Columbia Thermostat Fund		18

The Board of Trustees appointed a Chief Compliance Officer to the Trust in accordance with federal securities regulations. The Funds, along with other affiliated funds, will 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 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 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 as specified by the trustee. Benefits under the deferred compensation plan are payable when a trustee ceases to be a member of the Board of Trustees.

An affiliate may include any company in which a Fund owns five percent or more of its outstanding voting securities. On June 30, 2007, 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 33, 42, 50 and 59, respectively.

During the six months ended June 30, 2007, 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 International	$	3,841	$	281
Columbia USA		115		—
Columbia Acorn Select		3,036		—

5.  Borrowing Arrangements

The Trust participates in a $150 million credit facility, which was entered into to facilitate portfolio liquidity. Interest is charged to each participating fund based on its borrowings at a rate per annum equal to the Federal Funds rate plus 0.50%. In addition, a commitment fee of 0.08% per annum is accrued and apportioned among the participating funds based on their pro-rata portion of the unutilized line of credit. The commitment fee is included in "Other expenses" in the Statements of Operations. No amounts were borrowed by the Funds under this facility for the six months ended June 30, 2007.

6.  Investment Transactions

The aggregate cost of purchases and proceeds from sales other than short-term obligations for the six months ended June 30, 2007, were:

Columbia Acorn Fund

(in thousands)
Investment securities
Purchases	$	2,113,213
Proceeds from sales		1,942,800

Columbia Acorn International

(in thousands)
Investment securities
Purchases	$	10,522,574
Proceeds from sales		747,816

Columbia Acorn USA

(in thousands)
Investment securities
Purchases	$	210,429
Proceeds from sales		140,893

75

Columbia Acorn Family of Funds

Notes to Financial Statements (Unaudited), continued

Columbia Acorn International Select

(in thousands)
Investment securities
Purchases	$	82,074
Proceeds from sales		57,095

Columbia Acorn Select

(in thousands)
Investment securities
Purchases	$	541,174
Proceeds from sales		167,449

Columbia Thermostat Fund

(in thousands)
Investment securities
Purchases	$	72,382
Proceeds from sales		85,432

7.  Redemption Fees

For the six months ended June 30, 2007, the redemption fees imposed by Columbia Acorn International and Columbia Acorn International Select amounted to approximately $103,000 and $19,000, respectively, and are accounted for as additions to paid in capital.

8.  Other

For the six months ended June 30, 2007, Columbia Acorn Fund incurred two trading errors. Columbia Acorn Fund sold shares of Enerflex Systems resulting in a loss of $364. Additionally, Columbia Acorn Fund purchased shares of BioMarin resulting in a loss of $3,750. The Fund was reimbursed by Columbia WAM for the full amount of each loss.

These financial statements reflect certain adjusting journal entries recorded on the Columbia Thermostat Fund. While the impact of these adjusting entries was less than $.002 to each share class' NAV and therefore immaterial, they did cause the NAV's to round up by $0.01 for Class B, C and Z shares when compared to the NAV reported on the shareholder account statement you received by mail.

9.  Legal Proceedings

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

The Trust and Columbia WAM are also defendants in a class action lawsuit that alleges, in summary, that the Trust and Columbia WAM exposed shareholders of Columbia Acorn International Fund to trading by market timers by allegedly: (a) failing to properly evaluate daily whether a significant event affecting the value of the Fund's securities had occurred after foreign markets had closed but before the calculation of the Fund's net asset value ("NAV"); (b) failing to implement the Fund's portfolio valuation and share pricing policies and procedures; and (c) failing to know and implement applicable rules and regulations concerning the calculation of NAV (the "Fair Valuation Lawsuit"). The Seventh Circuit ruled that the plaintiffs' state law claims were preempted under federal law resulting in the dismissal of plaintiffs' complaint. Plaintiffs appealed the Seventh Circuit's ruling to the United States Supreme Court. The Supreme Cour t reversed the Seventh Circuit's ruling on jurisdictional grounds and the case was ultimately remanded to the state court.

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

On April 4, 2006, the plaintiffs and the Columbia defendants named in the MDL Action executed an agreement in principle intended to fully resolve all of the lawsuits consolidated in the MDL Action as well as the Fair Valuation Lawsuit. The court entered a stay after the parties executed a settlement agreement. The settlement has not yet been finalized or approved by the court.

Columbia WAM, the Columbia Acorn Funds and the Trustees of the Trust are also defendants in a consolidated lawsuit filed in the federal district court of Massachusetts alleging that Columbia WAM used Fund assets to make undisclosed payments to brokers as an incentive for the brokers to market the Funds over other mutual funds to investors. The complaint alleges Columbia WAM and the Trustees of the Trust breached certain common law duties and federal laws.

On November 30, 2005, the court dismissed all of the claims alleged against all of the parties in the consolidated complaint. The parties subsequently executed a formal settlement agreement resolving all claims in the litigation and the

76

plaintiffs dismissed their appeal. The settlement requires court approval, which has not yet been obtained.

On or about January 11, 2005, a putative class action lawsuit was filed in federal district court in Massachusetts against the Trust and the Trustees of the Trust, along with the Columbia Advisers, the sub-administrator of the Columbia Acorn Funds and the Wanger Advisors Funds. The plaintiffs allege that the defendants failed to submit Proof of Claims in connection with settlements of securities class action lawsuits filed against companies in which the Columbia Acorn Funds held positions. The complaint seeks compensatory and punitive damages, and the disgorgement of all fees paid to the Columbia Advisers.

Plaintiffs have voluntarily dismissed the Trust and its independent Trustees.

The Trust and Columbia WAM intend to defend these suits vigorously.

As a result of these matters, or any adverse publicity or other developments resulting from them, there may be increased redemptions or reduced sales of Fund shares, which could increase transaction costs or operating expenses, or have other adverse consequences for the Funds. However, based on currently available information, the Columbia Acorn Trust believes that the likelihood that these lawsuits will have a material adverse impact on any fund is remote, and Columbia WAM believes that the lawsuits are not likely to materially affect its ability to provide investment management services to the Funds.

77

[Excerpt from:]

Columbia Acorn Trust

Management Fee Evaluation of the Senior Officer

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

June 2007

78

Introduction

The New York Attorney General's Assurance of Discontinuance ("Order") entered into by Columbia Management Advisors, Inc. ("CMAI") and Columbia Management Distributors, Inc., ("CMDI" and collectively with "CMAI," "CMG") in February 2005, allows CMAI to manage or advise a mutual fund only if the trustees of the fund appoint a "Senior Officer" to perform specified duties and responsibilities. One of these responsibilities includes "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."

This is the first year that the Columbia Acorn Trust and Wanger Advisors Trust (collectively, the "Trusts") and each series thereof (the "Acorn Funds," "WAT Funds" or collectively, the "Funds") have been 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. The expenses can vary depending upon the class of shares held but usually include: (1) investment management or 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.

Columbia Wanger Asset Management, L.P. ("CWAM"), the adviser to the Funds, has proposed that with respect to the Acorn Funds, the Columbia Acorn Trust continue the existing separate agreements governing the first two categories listed above: an advisory agreement governing portfolio management, and an administration agreement governing certain administration and clerical services. Together the fees paid under these two agreements are referred to as "management fees." CWAM proposes that the WAT Funds continue the existing single agreement governing both investment advisory and administrative services. A single management fee would cover both services. Other fund expenses are governed by separate agreements, in particular agreements with two CWAM affiliates: CMDI, the broker-dealer that underwrites and distributes the Funds' shares, and Columbia Management Services, Inc. ("CMSI"), the Funds' transfer agent. In conformity with the terms of the Order, this evaluation, therefore, addresses only the advisory and administrative contracts, and does not extend to the other agreements.

According to the Order, the Senior Officer's evaluation must consider at least the 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 administrative fee contracts with CWAM in conformity with the requirements of the Order. This Report is

79

an annual evaluation required under the Order. In discharging their responsibilities, the independent Trustees have also consulted independent, outside counsel.

2006 Evaluation

This is the third annual evaluation prepared in connection with the Order. This evaluation follows the same structure as the earlier studies. Some areas are given more emphasis here, while others are given less. Still, the fundamental information gathered for this evaluation is largely the same as past years.

Process and Independence

The objectives of the Order are to insure the independent evaluation of the advisory fees paid by the Funds as well as to insure that all relevant factors are considered. In my view, this contract renewal 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 CWAM and CMG a comprehensive compilation of data regarding Fund performance and expenses, adviser profitability, and other information. The Board evaluated this information thoroughly and also explored CWAM's potential capacity restraints. 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 not influenced by the adviser. CWAM itself identified what it considers competing funds, and the Trustees considered that data as well.

In the course of its work, the Contract Committee gave careful consideration to the conclusions and recommendations contained in last year's evaluation. The Contract Committee gave particular emphasis to the issue of whether economies of scale were appropriately reflected in the Funds' fee schedules. Last year, the Board sought and CWAM agreed to additional breakpoints for two Funds, Acorn USA and Acorn Select. These breakpoints are above current asset levels, but clearly operate to share economies of scale with Fund shareholders. This year, at the Board's request, CWAM has proposed additional breakpoints for the WAT Funds, and Acorn International Select. This proposal is under consideration by the Board.

My evaluation of the advisory contract was shaped, as it was last year, 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 CMG or its affiliates, except for administrative purposes. 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 of the Board, 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, CMG 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 may not be increased before November 30, 2009. I have used these advisory fee levels— as modified last year to add certain breakpoints for Acorn USA and Acorn Select—in this evaluation because they are the fees in the current agreements that CWAM proposes should be continued. Hence, these fee levels are the starting point of an evaluation.

80

Conclusions

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

1.  Performance. The domestic Funds generally have achieved outstanding performance. The Acorn Fund, Acorn USA, Acorn Select, Wanger Select and Wanger US Smaller Companies all rank very favorably against their peers over the past five years. Although Acorn USA and Wanger US Smaller Companies had a difficult year in 2006, these returns are not characteristic of these funds, both of which have shown improved performance during the first quarter of 2007. The international Funds have relatively weaker long term records than the domestic funds, but recently have improved significantly and their one year rankings are excellent. Overall then, performance of the Funds is excellent.

2.  Management Fees relative to Peers. The management fee rankings for several of the Acorn Funds are generally more favorable to shareholders than those of their peer group funds. Management fees do, however, vary by Fund. Acorn Fund is the least expensive and the Acorn USA the most expensive. Acorn Fund is very competitive, while Acorn USA and Acorn Select were ranked by both Lipper and Morningstar at or below the median, and therefore impose higher fees than do the majority of their competitors. The WAT Funds also lag their competitors and impose higher fees than their peers.

3.  Administrative Fees. The Acorn Funds' administrative fee, which is uniform across all Funds, is at a level comparable to or less expensive than the fees imposed by their peers, provides for appropriate services to Funds, and affords breakpoints that lower the fee as assets increase. The WAT Funds pay a single fee for advisory and administrative services and hence do not benefit from administrative fee breakpoints, nor is it possible to assess their administrative costs relative to competitors.

4.  Management Fees relative to Institutional and Other Mutual Fund Accounts. CWAM's focus is on its mutual funds. It does not actively seek to manage separate or institutional accounts. 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 particular institutional account is significant in size and has been under CWAM's management for over 25 years.

5.  Costs to CWAM and its Affiliates. CWAM's direct costs do not appear excessive. Overhead and indirect costs allocated to CWAM by its parent organizations, however, are significant and increasing. CWAM's affiliates report operating losses and therefore do not appear to profit from CWAM's advisory agreement with the Funds.

6.  Profit Margins. CWAM's firm-wide, pre-marketing expense profit margins are at the top of the industry, though these comparisons are hampered by limited industry data. High profit margins are not unexpected for firms that manage large, successful funds and have provided outstanding investment performance for investors.

7.  Economies of Scale. Economies of scale do exist at CWAM and will expand as the assets of the Funds get larger. They are, however, only partially reflected in the management fee schedule for the Acorn Funds and not reflected at all in two of the four WAT Funds. Breakpoints above current asset levels have, however, been added to the more expensive funds, Acorn Select and Acorn USA. Nonetheless, if Fund assets continue to grow, under the Funds' current fee schedules, all Fund shareholders might not benefit in a manner generally commensurate with CWAM's increased profits. Management has proposed additional breakpoints for some of the Funds that, if implement, would result in greater sharing of economies of scale.

81

8.  Nature and Quality of Services. This category includes a variety of considerations that are difficult to quantify, yet can have a significant bearing on the performance of the Acorn Funds. Several areas merit comment.

  a.  Capacity. The Funds have continued to grow, posing ever greater challenges in deploying assets effectively. While trends here merit continued monitoring, CWAM appears to be managing assets effectively.

  b.  Compliance. CWAM has a reasonably designed compliance program that protects shareholders.

  c.  Administrative Services. The Funds benefit from a variety of administrative services that are performed by CWAM and CMAI.

9.  Process. In my opinion, the process of negotiating an advisory contract for the Funds has been conducted thoroughly and at arms' length. Further, the Trustees have sufficient information to evaluate management's proposal, and negotiate contract terms that are in the best interests of fund shareholders.

Recommendations

I believe the Trustees should:

1.  Continue to consider additional ways to restructure the advisory fee beyond the current breakpoint schedule to reflect more fully economies of scale.

2.  Consider unbundling of the advisory and administrative fees paid by the WAT Funds.

3.  Review the disparity in management fee levels between the Acorn International Fund and its related annuity-based fund, WAT International Small Cap Fund.

4.  Continue to monitor CWAM's capacity limitations to insure that the Funds' expanding assets do not impair investment performance.

Robert P. Scales

Senior Vice President,
Chief Legal Officer
and General Counsel

June 18, 2007

82

Columbia Acorn Family of Funds

Class Z Share Information

Minimum Initial Investment in Columbia Acorn International, Columbia Acorn International Select and Columbia Thermostat Fund		$2,500† $1,000 for an IRA
Minimum Initial Investment in Columbia Acorn Fund and Columbia Acorn USA	$	75,000	†
Minimum Initial Investment in Columbia Acorn Select	$	100,000	*†
Minimum Subsequent Investment in all Funds	$	50
Exchange Fee		None

Columbia Acorn Fund	ACRNX
Management Fee	0.64	%
12b-1 Fee	None
Other Expenses	0.09	%
Net Expense Ratio	0.73	%
Columbia Acorn International	ACINX
Management Fee	0.76	%
12b-1 Fee	None
Other Expenses	0.14	%
Net Expense Ratio	0.90	%
Columbia Acorn USA	AUSAX
Management Fee	0.86	%
12b-1 Fee	None
Other Expenses	0.11	%
Net Expense Ratio	0.97	%
Columbia Acorn International Select	ACFFX
Management Fee	0.94	%
12b-1 Fee	None
Other Expenses	0.25	%
Net Expense Ratio	1.19	%
Columbia Acorn Select	ACTWX
Management Fee	0.80	%
12b-1 Fee	None
Other Expenses	0.12	%
Net Expense Ratio	0.92	%
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, 2007, and for Columbia Thermostat Fund include the effect of Columbia Wanger Asset Management's undertaking to reimburse the Fund for any ordinary operating expenses (exclusive of interest and fees on borrowings, and expenses associated with the Fund's investment in other investment companies), net of custody fees paid indirectly, in excess of the annual rate of 0.25% of the average daily net assets. Columbia Thermostat Fund's reimbursement arrangement is contractual through April 30, 2008. The Funds' adviser and/or affiliates have agreed to contractually waive a portion of "other expenses" through March 31, 2007.

  *  Effective June 25, 2007, the board of trustees voted to increase the minimum initial investment for Columbia Acorn Select from $50,000 to $100,000.

  **  Does not include estimated fees and expenses of 0.72% incurred by the Fund from the underlying portfolio funds.

  †  Certain exclusions may apply.

83

Columbia Acorn Family of Funds

Trustees

Robert E. Nason

Chairman

Allan B. Muchin

Vice Chairman

Laura M. Born

Maureen M. Culhane

Margaret Eisen

Jerome Kahn, Jr.

Steven N. Kaplan

David C. Kleinman

Charles P. McQuaid

James A. Star

Ralph Wanger

Patricia H. Werhane

John A. Wing

Officers

Charles P. McQuaid

President

Ben Andrews

Vice President

Michael G. Clarke

Assistant Treasurer

Jeffrey R. Coleman

Assistant Treasurer

J. Kevin Connaughton

Assistant Treasurer

P. Zachary Egan

Vice President

Peter T. Fariel

Assistant Secretary

John M. Kunka

Assistant Treasurer

Joseph C. LaPalm

Vice President

Bruce H. Lauer

Vice President, Treasurer and Secretary

Louis J. Mendes III

Vice President

Robert A. Mohn

Vice President

Christopher J. Olson

Vice President

Linda K. Roth-Wiszowaty

Assistant Secretary

Robert P. Scales

Senior Vice President, Chief Compliance Officer
and General Counsel

Investment Adviser

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

1-800-922-6769

Distributor

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

Transfer Agent, Dividend Disbursing Agent

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

1-800-345-6611

Legal Counsel

Bell, Boyd & Lloyd LLP
Chicago, Illinois

This report, including the schedules of investments, is submitted for the general information of the shareholders of Columbia Acorn Trust. This report is not authorized for distribution unless preceded or accompanied by a prospectus. An investor should carefully consider charges and expenses before investing. To obtain a prospectus containing this and other information, please call (800) 922-6769 or visit our website (shown below). Please read the prospectus carefully before you invest or send money.

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 from the Fund's website.

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.

Please consider the investment objectives, risks, charges and expenses for the fund carefully before investing. Contact your financial advisor for a prospectus, which contains this and other important information about the fund. You should read it carefully before you invest.

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

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

www.columbiafunds.com

Our e-mail address is:

ServiceInquiries@ColumbiaManagement.com

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

84

Columbia Acorn Family of Funds

Class Z Shares

Semiannual Report – June 30, 2007

Columbia Management_®

PRESORTED

FIRST-CLASS MAIL

U.S. POSTAGE PAID

HOLLISTON, MA

PERMIT NO. 20

©2007 Columbia Management Distributors, Inc.

One Financial Center, Boston, MA 02111-2621

800-345-6611 www.columbiafunds.com

SHC-44/132914-0607 (08/07) 07/43028

2Q

Columbia Acorn
Family of Funds

Class ABC Shares

Semiannual Report

June 30, 2007

n  Columbia^TM   Acorn® Fund

n  Columbia^TM Acorn International®

n  Columbia^TM Acorn USA®

n  Columbia^TM Acorn International Select^SM

n  Columbia^TM Acorn Select^SM

n  Columbia^TM Thermostat Fund^SM

Managed by Columbia Wanger Asset Management, L.P.

NOT FDIC INSURED

NOT BANK ISSUED

May Lose Value

No Bank Guarantee

>2007 Mid-Year Distributions

The following table lists the Funds' mid-year distributions. The record date was June 4, 2007. The ex-dividend date was June 5, 2007 and the payable date was June 6, 2007.

	Short-term Capital Gains		Long-term Capital Gains		Ordinary Income		Reinvestment Price
Columbia
Acorn Fund Class A, B and C	$	0.0462	$	0.3404		None	$	32.43—	A
							$	30.95—	B
							$	30.83 —	C
Columbia
Acorn International Class A		None	$	0.2470	$	0.0059	$	45.24 —	A
Columbia
Acorn International Class B and C		None	$	0.2470		None	$	44.37—	B
							$	44.29 —	C
Columbia
Acorn USA Class A, B and C		None	$	0.2797		None	$	31.05—	A
							$	29.68—	B
							$	29.60 —	C
Columbia
Acorn International Select Class A		None		None	$	0.0752	$	30.61 —	A
Columbia
Acorn Select Class A, B and C	$	0.0898	$	0.0978		None	$	30.74—	A
							$	29.41—	B
							$	29.32 —	C
Columbia
Thermostat Fund Class A	$	0.0207	$	0.2751	$	0.0312	$	12.90 —	A
Columbia
Thermostat Fund Class B and C	$	0.0207	$	0.2751		None	$	12.94—	B
							$	12.92 —	C

The views expressed in "Squirrel Chatter II" and "In a Nutshell" commentary 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 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. References to specific company securities should not be construed as a recommendation or investment advice.

Columbia Acorn Family of Funds

Table of Contents

Net Asset Value Per Share	2
Share Class Performance	3
Fund Performance vs. Benchmarks	4
Squirrel Chatter II: Buyout Boom	5
Understanding Your Expenses	10
Columbia Acorn Fund
In a Nutshell	12
At a Glance	13
Major Portfolio Changes	24
Statement of Investments	26
Columbia Acorn International
In a Nutshell	14
At a Glance	15
Major Portfolio Changes	37
Statement of Investments	39
Portfolio Diversification	45
Columbia Acorn USA
In a Nutshell	16
At a Glance	17
Major Portfolio Changes	46
Statement of Investments	47

Columbia Acorn International Select
In a Nutshell	18
At a Glance	19
Major Portfolio Changes	53
Statement of Investments	54
Portfolio Diversification	57
Columbia Acorn Select
In a Nutshell	20
At a Glance	21
Major Portfolio Changes	58
Statement of Investments	59
Columbia Thermostat Fund
In a Nutshell	22
At a Glance	23
Statement of Investments	62
Columbia Acorn Family of Funds
Statements of Assets and Liabilities	64
Statements of Operations	65
Statements of Changes in Net Assets	66
Financial Highlights	70
Notes to Financial Statements	77
Management Fee Evaluation of the Senior Officer	84
Columbia Acorn Family of Funds Information	91

1

Columbia Acorn Family of Funds

Net Asset Value Per Share as of 6/30/07

	Columbia Acorn Fund		Columbia Acorn International		Columbia Acorn USA		Columbia Acorn International Select		Columbia Acorn Select		Columbia Thermostat Fund
Class A	$	31.94	$	45.59	$	30.37	$	30.82	$	30.35	$	12.80
Class B	$	30.47	$	44.69	$	29.02	$	29.74	$	29.03	$	12.84
Class C	$	30.35	$	44.61	$	28.93	$	29.68	$	28.94	$	12.82

Descriptions of indexes included in this report:

•  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.

•  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^TM 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.

•  S&P/Citigroup EMI Global ex-US is an unmanaged index consisting of the bottom 20% of institutionally investable capital of developed and emerging countries, outside the United States.

•  S&P/Citigroup Global ex-US Cap Range $500mm-$5bn 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.

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

•S&P/Citigroup World ex-US Cap Range $2–10B is a subset of the broad market selected by the index sponsor representing the mid-cap developed market excluding the United States.

•Lipper Indexes include the largest funds tracked by Lipper, Inc. in the named category. Lipper Mid-Cap Growth Index, 30 mid-cap growth funds; Lipper Mid-Cap Core Funds Index, 30 mid-cap core funds; Lipper International Funds Index, 30 largest non-U .S. funds, not including non-U.S. small-cap funds; Lipper International Small-Cap Funds Index, 10 largest non-U.S. funds investing in small-cap companies, including Columbia Acorn International; Lipper Small-Cap Core Funds Index, 30 largest small-cap core funds, including Columbia Acorn Fund. Lipper Flexible Portfolio Funds Index is an equal dollarweighted index of the 30 largest mutual funds within the Flexible Portfolio fund classification, as defined by Lipper.

•Lehman Brothers U.S. Credit Intermediate Bond Index is the intermediate component of the U.S. Credit Index. The U.S. Credit Index includes publicly issued U.S. corporate and foreign debentures and secured notes that meet specified maturity, liquidity, and quality requirements.

Indexes are not managed and do not incur fees or expenses. It is not possible to invest directly in an index.

2

Columbia Acorn Family of Funds

Share Class Performance Average Annual Total Returns through 6/30/07

	Class A						Class B						Class C
	Without Sales Charge			With Sales Charge			Without Sales Charge			With Sales Charge			Without Sales Charge			With Sales Charge
Columbia Acorn Fund (10/16/2000)
3 months*		6.60	%		0.47	%		6.45	%		1.45	%		6.41	%		5.41	%
Year to date*		11.37	%		4.97	%		11.05	%		6.05	%		10.94	%		9.94	%
1 year		20.32	%		13.40	%		19.60	%		14.60	%		19.37	%		18.37	%
3 years		16.86	%		14.57	%		16.08	%		15.33	%		15.94	%		15.94	%
5 years		17.63	%		16.24	%		16.85	%		16.63	%		16.76	%		16.76	%
Life of fund		14.32	%		13.32	%		13.58	%		13.58	%		13.51	%		13.51	%
Columbia Acorn International (10/16/2000)
3 months*		8.53	%		2.29	%		8.36	%		3.36	%		8.33	%		7.33	%
Year to date*		14.41	%		7.83	%		14.09	%		9.09	%		14.00	%		13.00	%
1 year		34.52	%		26.78	%		33.67	%		28.67	%		33.47	%		32.47	%
3 years		30.34	%		27.79	%		29.46	%		28.86	%		29.34	%		29.34	%
5 years		23.96	%		22.50	%		23.11	%		22.93	%		23.06	%		23.06	%
Life of fund		12.47	%		11.48	%		11.72	%		11.72	%		11.68	%		11.68	%
Columbia Acorn USA (10/16/2000)
3 months*		5.70	%		-0.37	%		5.56	%		0.56	%		5.50	%		4.50	%
Year to date*		9.36	%		3.07	%		9.02	%		4.02	%		8.93	%		7.93	%
1 year		15.69	%		9.04	%		14.98	%		9.98	%		14.77	%		13.77	%
3 years		13.38	%		11.16	%		12.63	%		11.84	%		12.49	%		12.49	%
5 years		14.73	%		13.38	%		13.97	%		13.73	%		13.90	%		13.90	%
Life of fund		14.05	%		13.05	%		13.32	%		13.32	%		13.27	%		13.27	%
Columbia Acorn International Select (10/16/2000)
3 months*		7.31	%		1.14	%		7.13	%		2.13	%		7.11	%		6.11	%
Year to date*		11.62	%		5.20	%		11.26	%		6.26	%		11.16	%		10.16	%
1 year		34.62	%		26.88	%		33.72	%		28.72	%		33.51	%		32.51	%
3 years		26.42	%		23.95	%		25.63	%		24.99	%		25.44	%		25.44	%
5 years		21.58	%		20.15	%		20.77	%		20.58	%		20.68	%		20.68	%
Life of fund		9.00	%		8.04	%		8.26	%		8.26	%		8.22	%		8.22	%
Columbia Acorn Select (10/16/2000)
3 months*		9.05	%		2.78	%		8.89	%		3.89	%		8.84	%		7.84	%
Year to date*		16.64	%		9.93	%		16.26	%		11.26	%		16.18	%		15.18	%
1 year		32.17	%		24.57	%		31.36	%		26.36	%		31.13	%		30.13	%
3 years		19.35	%		17.02	%		18.50	%		17.79	%		18.38	%		18.38	%
5 years		18.06	%		16.67	%		17.24	%		17.02	%		17.18	%		17.18	%
Life of fund		14.54	%		13.54	%		13.77	%		13.77	%		13.72	%		13.72	%
Columbia Thermostat Fund (3/3/2003)†
3 months*		1.98	%		-3.89	%		1.89	%		-3.09	%		1.81	%		0.82	%
Year to date*		4.25	%		-1.75	%		4.07	%		-0.93	%		3.91	%		2.91	%
1 year		12.58	%		6.11	%		12.04	%		7.04	%		11.75	%		10.75	%
3 years		8.77	%		6.65	%		8.19	%		7.33	%		8.00	%		8.00	%
Life of fund		11.88	%		10.36	%		11.21	%		10.88	%		11.07	%		11.07	%

*Not annualized.

Performance data quoted represents past performance and current performance may be lower or higher. Past performance is no guarantee of future results. The investment return and principal value will fluctuate so that shares, when redeemed, may be worth more or less than their original cost. Please visit columbiafunds.com for daily and most recent month-end performance 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 prospectus that is current as of the date of this report. Differences in expense ratios disclosed elsewhere in this report may result from including fee waivers and reimbursements as well as different time periods used in calculating the ratios. Columbia Acorn Fund: Class A: 1.05%; Class B: 1.63%; Class C: 1.84%. Columbia Acorn International: Class A: 1.27%; Class B: 1.86%; Class C: 2.05%. Columbia Acorn USA: Class A: 1.30%; Class B: 1.89%; Class C: 2.09%. Columbia Acorn International Select: Class A: 1.63%; Class B: 2.23%; Class C: 2.42%. Columbia Acorn Select: Class A: 1.27%; Class B: 1.88%; Class C: 2.08%. Columbia Thermostat Fund has a contractual expense waiver or reimbursement that expires April 30, 2008. Expense ratios without and with the contractual waiver, including fees and expenses associated with the Fund's investments in other investment companies are: C lass A: 1.35%, 1.19%; Class B: 1.88%, 1.69%; Class C: 2.15%, 1.94%, respectively.

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

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

3

Columbia Acorn Family of Funds

Fund Performance vs. Benchmarks Class A Shares, without sales charge, Average Annual Total Returns through 6/30/07

	2nd quarter*			Year to date*			1 year			3 years			5 years			Life of Fund
Columbia Acorn Fund (LACAX) (10/16/00)		6.60	%		11.37	%		20.32	%		16.86	%		17.63	%		14.32	%
Russell 2500		4.94	%		8.67	%		18.74	%		14.97	%		15.30	%		11.04	%
S&P 500		6.28	%		6.96	%		20.59	%		11.68	%		10.71	%		3.09	%
Lipper Small-Cap Core Funds Index		6.21	%		9.54	%		17.17	%		13.74	%		13.79	%		10.68	%
Lipper Mid-Cap Core Funds Index		6.06	%		11.09	%		20.82	%		14.71	%		14.16	%		8.19	%
Columbia Acorn International (LAIAX) (10/16/00)		8.53	%		14.41	%		34.52	%		30.34	%		23.96	%		12.47	%
S&P/Citigroup EMI Global ex-US		7.37	%		14.85	%		35.90	%		29.34	%		26.03	%		17.17	%
S&P/Citigroup Global ex-US Cap Range $500mm-$5bn		8.02	%		15.47	%		35.50	%		29.32	%		26.22	%		17.59	%
MSCI EAFE Index		6.40	%		10.74	%		27.00	%		22.24	%		17.73	%		8.87	%
Lipper Int'l Small-Cap Funds Index		7.57	%		14.85	%		33.39	%		28.48	%		25.78	%		15.75	%
Columbia Acorn USA (LAUAX) (10/16/00)		5.70	%		9.36	%		15.69	%		13.38	%		14.73	%		14.05	%
Russell 2000		4.42	%		6.45	%		16.43	%		13.45	%		13.88	%		9.94	%
Lipper Small-Cap Core Funds Index		6.21	%		9.54	%		17.17	%		13.74	%		13.79	%		10.68	%
S&P 500		6.28	%		6.96	%		20.59	%		11.68	%		10.71	%		3.09	%
Columbia Acorn Int'l Select (LAFAX) (10/16/00)		7.31	%		11.62	%		34.62	%		26.42	%		21.58	%		9.00	%
S&P/Citigroup World ex-US Cap Range $2-10B		6.08	%		12.04	%		29.92	%		26.26	%		22.67	%		15.04	%
MSCI EAFE Index		6.40	%		10.74	%		27.00	%		22.24	%		17.73	%		8.87	%
Lipper International Funds Index		7.49	%		11.48	%		28.40	%		22.84	%		17.55	%		9.47	%
Columbia Acorn Select (LTFAX) (10/16/00)		9.05	%		16.64	%		32.17	%		19.35	%		18.06	%		14.54	%
S&P MidCap 400		5.84	%		11.98	%		18.51	%		15.15	%		14.17	%		10.28	%
Lipper Mid-Cap Growth Index		9.51	%		14.71	%		21.98	%		14.76	%		13.28	%		0.67	%
S&P 500		6.28	%		6.96	%		20.59	%		11.68	%		10.71	%		3.09	%
Columbia Thermostat Fund (CTFAX) (3/3/03)†		1.98	%		4.25	%		12.58	%		8.77	%		NA			11.88	%
S&P 500		6.28	%		6.96	%		20.59	%		11.68	%		NA			16.42	%
Lehman Brothers U.S. Credit Intermediate Bond Index		-0.40	%		1.28	%		6.34	%		3.79	%		NA			3.70	%
Lipper Flexible Portfolio Funds Index		4.96	%		6.79	%		16.83	%		11.10	%		NA			14.13	%

*Not annualized.

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

Annual operating expense ratios are as stated in each Fund prospectus that is current as of the date of this report. Differences in expense ratios disclosed elsewhere in this report may result from including fee waivers and reimbursements as well as different time periods used in calculating the ratios. Columbia Acorn Fund: Class A: 1.05%; Class B: 1.63%; Class C: 1.84%. Columbia Acorn International: Class A: 1.27%; Class B: 1.86%; Class C: 2.05%. Columbia Acorn USA: Class A: 1.30%; Class B: 1.89%; Class C: 2.09%. Columbia Acorn International Select: Class A: 1.63%; Class B: 2.23%; Class C: 2.42%. Columbia Acorn Select: Class A: 1.27%; Class B: 1.88%; Class C: 2.08%. Columbia Thermostat Fund has a contractual expense waiver or reimbursement that expires April 30, 2008. Expense ratios without and with the contractual waiver, including fees and expenses associated with the Fund's investments in other investment companies are: C lass A: 1.35%, 1.19%; Class B: 1.88%, 1.69%; Class C: 2.15%, 1.94%, respectively.

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

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

All indexes are unmanaged and returns include reinvested distributions. It is not possible to invest directly in an index. For index definitions, see Page 2 of this report.

4

Squirrel Chatter II: Buyout Boom

In last year's annual report, we mentioned that 26 Columbia Acorn Fund stocks were subject to takeover bids during the year. Takeovers certainly helped performance and we were pleased that buyers validated our fundamental research process by finding lots of our companies to be attractive.

In the first half of 2007, the buyout boom continued to accelerate. In just six months, 27 Columbia Acorn Fund stocks announced takeovers, beating the Fund's full year 2006 record. Columbia Acorn USA had 15 takeover stocks in common with Columbia Acorn Fund and one additional buyout not owned by Columbia Acorn Fund. Columbia Acorn International had three takeovers that overlapped with Columbia Acorn Fund and another that did not. Columbia Acorn Select and Columbia Acorn International Select had one takeover each; both were also held by Columbia Acorn Fund.

Generally, buyouts come in two basic flavors: strategic and financial. Strategic buyouts are often done by similar companies that want to pursue synergies, such as cost savings or enhanced products, production, distribution or pricing. Strategic buyers are usually other public companies and sometimes use their stock to pay for all or part of the acquisition. After some stock deals, we've kept the acquiring company's stock as a long-term investment.

Financial buyouts have historically been executed by private equity partnerships with private equity firms as general partners and other entities, such as pension funds and endowments, as limited partners. Financial partnerships usually borrow 70% to 85% of the acquisition price in order to enhance returns and minimize taxes on the acquired business.¹ Company management sometimes like to sell to private partners, as (1) they often get stock in the privatized company to stay and manage the business, and (2) they no longer have to deal with pesky securities analysts.

Our first half 2007 buyout announcements were a mixed lot. About 55% were strategic and 45% financial. The takeover terms have ranged from excellent to disappointing, though none so far this year have been "takeunders," at below last trade prices. We've had offers for big positions and small ones, and for long-standing holdings and newer ideas. Following are summaries of the takeover announcements made in the first half of 2007:

Takeover Log

January 8: United Surgical Partners, an operator of outpatient surgical centers, agreed to sell to a group led by Welsh, Carson, Anderson & Stowe, for $31.05 per share. Although we believed the valuation was fair based on reported results, we thought fundamentals would improve and the stock would have had high returns over the long run.

January 10: Alliance Atlantis Communications announced it was selling to a partnership including Goldman Sachs and CanWest Global Communications for C$53.² We first bought Alliance Atlantis in 2003, when it became focused on its more successful areas, the popular CSI television series and cable TV channels in Canada. Columbia Acorn Fund sold much of its position after the announcement but our remaining holding is up 150% from its cost.

February 5: Hanover Compressor agreed to merge with Universal Compression Holdings, a competitor, in a deal for stock. Both companies rent compressors to the natural gas industry, and the companies believe the combination will result in cost savings and larger service areas. We agree and Columbia Acorn USA as of press time kept its position in Hanover.

February 8: Edgars Consolidated Stores, a South African retailer, said it would sell to Bain Capital. Edgars' offer was 50% over its price prior to deal news back in October 2006, but was not at a premium to similar public companies. We owned Edgars in Columbia Acorn Fund and Columbia Acorn International, correctly believing that new management would enable the company to benefit from an improving regional economy. While the buyout price was somewhat disappointing, both funds booked at least a double in under three years.

February 12: A twin-deal day. First, UrAsia Energy, a Canadian uranium miner with operations in Kazakhstan, announced a merger for sxr Uranium One stock. Uranium One is a Canadian uranium miner with operations primarily in South Africa. This was Columbia Acorn Select's only deal. With Columbia Acorn Fund and Columbia Acorn International also owning the stock, it was our largest dollar deal, exceeding

5

$250 million across the three funds. We continue to like uranium mining economics and the funds now own Uranium One. Second, Witness Systems agreed to sell to Verint, a strategic buyer, for $27.50 per share, a price we considered to be fair.

February 14:TALX announced a sellout to Equifax for a cash and stock deal valued at $35.50, an 11% premium to TALX's last closing price. We were disappointed by the offer, though it was more than a 20% premium to our cost. While that was an excellent compound rate of return as we owned the stock for only several months, we'd rather hold stocks for much longer periods and potentially make more money.

February 19: Florida Rock agreed to merge with fellow aggregates company Vulcan Materials for cash and stock worth a stated $68 per share, a 45% premium to Florida's prior closing price. We like the business as barriers to entry are high—people don't want rock mines in their back yards—and transportation costs keep out remote competitors. Consequently, it was one of our larger holdings. We thought Florida's stock price had seemed irrationally depressed due to concerns about the housing industry and Vulcan noticed. As of June 30, both Columbia Acorn Fund and Columbia Acorn USA had more than a double in their investment in Florida Rock and Columbia Acorn Fund also started a position in Vulcan.

February 21: Central Parking announced a sale to private equity consortium KCPC Holdings for $22.53 per share in cash. Central Parking had reportedly turned down offers that were $15 to $16 in the middle of 2006, but somehow real estate values have surged since then. We consider the new price to be fair.

March 2: Dendrite International, a provider of software and services to pharmaceutical marketing departments, reported that it would sell out to Cedegim, a French software company, for $16 in cash. We believed that Dendrite provided value to its customers, but we were disappointed by a lack of consistent growth. We think the deal was at a fair price given earnings volatility.

March 6: K&F Industries agreed to sell to Meggitt PLC, a fellow producer of aircraft wheels and brakes, for $27 per share in cash. The price represented just a 10% premium to the prior day's close and appeared cheap compared to cash flow. The company did allow competing bids, but none emerged. We believe we bought the stock at the right time in Columbia Acorn Fund and Columbia Acorn USA, as it returned over 60% in the 15 months that we held it.

March 15: WebEx announced a sellout to Cisco for $57 per share in cash, a 23% premium to its March 14 closing price. This was one of our quickest and smallest deals, as we had started buying the stock for Columbia Acorn Fund in January. Like the TALX deal, we got a fine rate of return, but we would have rather made potentially more dollars over a longer period of time.

March 19: ServiceMaster entered into a deal to sell to Clayton, Dubilier & Rice, a private equity firm, for $15.625 per share in cash. ServiceMaster was a great stock until about 1998 but it subsequently struggled. We bought it last year for Columbia Acorn Fund, thinking that new management could restructure and grow the business. Instead, the company decided to sell out at a relatively modest premium. Once again our rate of return was fine but we did not earn large dollars over the longer term.

March 23: Kronos agreed to sell to a group led by Hellman & Friedman for $55 per share in cash. We first bought Kronos over 10 years ago as a downstream-from-technology investment; the company substituted semiconductors for electromechanical devices in employee timeclocks. As years progressed, Kronos expanded its product portfolio with software offerings including shift scheduling, human resource management and recruiting. Earnings growth was erratic due to economic and product cycles and that provided some opportunities for long-term investors. We view the deal price as reasonable. Kronos was our second largest deal this year, as Columbia Acorn Fund and Columbia Acorn USA cashed out for over $180 million.

April 19: Van Houtte, a Canadian gourmet coffee equipment and services company, said it had a non-binding offer from an undisclosed buyer of C$25 per share, a 1% premium to its average price over the prior 30 days. The stock spiked up from C$17 in January, after the company said it was reviewing strategic options. In May the company entered into a definitive agreement and identified the buyer as Littlejohn & Co, a private equity firm. While we were disappointed with the sale price, Columbia Acorn International booked about a 40% profit in 14 months.

April 24: Highland Hospitality said it would sell out to JER Partners, a private equity firm focused on real estate, for $19.50 per share. Though we had cut our real estate holdings several years ago, we believed that the hotel business had favorable supply/demand characteristics and that Highland added value by acquiring and improving properties. We began buying the stock in December 2003. Upon the close of the deal in late July, Columbia Acorn Fund and

6

Columbia Acorn USA realized over 70% gains from its average cost, in addition to dividends previously booked.

May 7: Armor Holdings, a military vehicle and armor business, announced a sellout to BAE Systems, a UK defense conglomerate, for $88 per share in cash. We started buying the stock for Columbia Acorn Fund in December 2006, believing that the demand for military armor would grow over the long term and that Armor was well positioned. We thought the takeout price was fair, and when the deal closed following the period end, the Fund realized a 61% gain.

May 14: Viasys Healthcare agreed to sell out to Cardinal Health for $42.75 per share in cash, a 36% premium to its last closing price. We thought that price was a fair multiple on earnings and cash flow, and we subsequently learned that Viasys pursued a lengthy bidding process in order to obtain the highest price. We applaud management and directors for that effort. Upon the deal's close in June, Columbia Acorn Fund realized a 130% gain and Columbia Acorn USA tripled its investment.

May 15: Agile Software, a company that produces programs to handle changes in product design, said it would sell out to Oracle for $8.10 per share. The price represented a 12% premium to the stock's last trade. We bought the stock a year earlier, correctly believing that sales would increase and profits would commence.

May 21: Cellular phone company Alltel announced a sale to private equity buyers TPG Capital and Goldman Sachs for $71.50 cash per share. Our Alltel shares were derived from a previous takeover, as a result of it buying Western Wireless, a rural cellphone company. We had expected Alltel to sell out and were relieved upon the announcement because we were leery of increasing competition. We sold our remaining positions shortly after the announcement, realizing over 400% gains over our original Western Wireless costs, in both Columbia Acorn Fund and Columbia Acorn USA.

Also on May 21, Cytyc, a dominant producer of consumable diagnostic and surgical products for women's health, agreed to sell out to Hologic for a combination of cash and stock. The merger appears to make sense for both companies as we believe the combined company can boost sales and reduce costs. We have owned Cytyc since early 2005 in Columbia Acorn Fund and, at quarter end, showed a 75% profit on our investment.

May 22: Crescent Real Estate Equities, which primarily owns office buildings, announced a sale to Morgan Stanley Real Estate, a private fund, for cash. The $22.80 price was just a 6% premium to the stock's prior close, which barely offsets dividends that were cancelled until the deal is expected to close in the third quarter. Furthermore, the price represented a 5% to 10% discount to what we then believed the company was worth.

May 30: Ceridian, a provider of payroll processing, other HR services, trucker transactions processing and gift cards, agreed to sell to Thomas H. Lee Partners and Fidelity National Financial for $36 cash per share. We believe that Ceridian's core HR business is a solid franchise undergoing internal improvement and its other businesses are gems. Governance, however, became somewhat like a soap opera as an activist hedge fund bought a 15% interest, agitated for strategic restructuring, and began negotiating with a division head, who then got fired. That is all a shame, as we think the $36 price undervalues the company's potential.

June 15: Penn National Gaming, a regional casino operator, said it would sell out to a private group, which includes management, Fortress Investment and Centerbridge Partners, for $67 per share in cash. The bid was a 31% premium to the prior day's stock price, and at what we considered to be a fair multiple of cash flow. With Penn's proposed sale later this year, and Kerzner International's and Station Casino's announced sellouts last year, there are expected to be few public small- and mid-cap casino companies remaining.

June 18: Footwear retailer Genesco gave itself the boot as a public company, agreeing to sell out to Finish Line, another footwear retailer, for $54.50 cash per share. In April and May, the board of Genesco had rejected lower offers from Foot Locker. We think the $54.50 price is fair and we applaud the board for holding out for that price.

June 20: Nuveen Investments said it would be acquired by a private group lead by Madison Dearborn Partners, for $65 per share in cash. We like the investment management business, and Columbia Acorn Fund started buying Nuveen in late 2004. Columbia Acorn Select later bought a position. Unfortunately, in early 2007 we trimmed Columbia Acorn Fund's holdings and sold out of Columbia Acorn Select's position due to valuation and fears that growth would slow. Columbia Acorn Fund will realize nearly a 100% gain on its remaining shares if the deal is executed under its announced terms.

7

June 26: Stork, a Netherlands-based conglomerate, agreed to sell to private equity firm Candover Investments. The price, 47 Euros cash per share, represented a 12% premium to the stock's prior close. Stork has been harassed by activist shareholders demanding that it be split up, and the company sees the sale as a way to resolve the dispute. We believe the small premium does not reflect Stork's underlying value. We understand that a supermajority vote is needed to approve the buyout and we think the 47 Euro price may need to be increased for a transaction to occur. Columbia Acorn Fund, Columbia Acorn International and Columbia Acorn International Select owned the stock.

June 27: Chittenden, a New England bank, announced it would sell to People's United Financial, another company held by Columbia Acorn Fund and Columbia Acorn USA, for a combination of stock and cash. The banking industry in the United States has been consolidating for a long time, and Columbia Acorn Fund has benefited from a lot of bank sellouts. While we believe this sellout price is fair and Chittenden was certainly a profitable investment for Columbia Acorn Fund and Columbia Acorn USA, our funds' positions in People's United fell on the news somewhat more than their positions in Chittenden rose.

June 29: Another rural cellular phone company, Dobson Communications, announced it would sell. This deal is for cash and the buyer is AT&T, which operates nearby cellular systems that utilize the same technology as Dobson. Columbia Acorn Fund has owned cellphone franchises since the industry began in the 1980s and has benefited from numerous sellouts. Similar to the casino industry, few small- and mid-cap public cellular companies remain.

Trillion Dollar Question

Buyout booms tend to run in cycles. Typically, private equity is able to raise more equity capital after a few years of good returns, and is able to raise debt funding when interest rates for "junk" bonds are at relatively low premiums to quality bonds. Then buyout momentum accelerates. Increased private equity activity seems to spur more strategic acquisitions and buyout prices rise.

The dollar volume of private equity buyouts in the United States and Europe averaged around $30 billion a year from 2000 to 2002, and then ramped to an unprecedented level in 2006, around $384 billion!³ While the dollar amount of private buyouts in 2006 broke records, as a percentage of stock market valuation, it was barely half of 1988's level. Private equity recently had about $250 billion of equity capital available for buyouts, and was continuing to raise a lot more.⁴ Adding debt to this equity suggests that private equity would be able to buy over a trillion dollars of assets. The trillion dollar question is whether lenders will continue to fund lots of buyouts at low interest rates.

Credit markets in the first half of 2007 were very loose relative to historical standards. While we think buyout prices were high, we believe they had not yet reached "bubble" levels. We do not think we have seen the marquee "big and dumb" deals, which would normally suggest the buyout boom is nearing an end.

However, credit market conditions changed considerably after the June 30 end of this report period. Home mortgage defaults kept growing, especially for sub-prime mortgages. Mortgage-backed security prices fell, triggering huge losses for some hedge funds and creating concerns about possible losses elsewhere. Credit markets tightened overall and premiums for "junk" bonds increased.

Previously announced financial buyout deals generally have gotten funded, at first with sweetened terms for bond financing and later by bank commitments rather than primarily by bonds. Banks appear to be honoring existing financing commitments but seem to be limiting additional obligations.

At press time, the debt market was chaotic. While several high quality corporations were able to issue new bonds, risky borrowers appear locked out. We don't know what will happen next. We believe that there is a reasonable chance that the mortgage-backed security problem will be contained and its casualties clearly defined, allowing the remainder of the credit markets to return to normal. Higher quality financial buyouts could then resume. We feel there is also a chance that credit markets will remain tight for a long time, severely limiting new buyouts.

We usually buy stocks in order to grow with them for a long time, not to participate in a buyout within a few

8

months. We recognize that buyout cycles come and go. We benefited from the buyout cycle and will likely continue to benefit from it should it resume, but we will not change our investment objectives, strategy, style or process.

Charles P. McQuaid

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

While some of the deals have closed, there can be no assurance that the remaining transactions discussed above will be consummated on the terms and conditions, or that the Funds will profit to the extent, described herein.

All holding gains mentioned are calculated based on tax lots of securities held at the time of publication and additional tax lots may have been previously sold at higher costs for some stocks.

¹  Data taken from a presentation given by Steven Kaplan, Neubauer Family Professor of Entrepreneurship and Finance, University of Chicago Graduate School of Business, to the Chicago Analyst Society on June 11, 2007. Steven is also a trustee of the Columbia Acorn Trust.

²  The "C" denotes Canadian dollars here and elsewhere in the essay.

³  "The Financing of Large Buyouts: An Empirical Analysis," a paper coauthored by Ulf Axelson, Tim Jenkinson, Per Stromberg and Michael Weisbach. Preliminary version dated April 3, 2007.

⁴  Ibid.

Fund weightings at June 30, 2007, in the holdings mentioned were as follows:

Alliance Atlantis Communication: Columbia Acorn Fund, 0.1%

Hanover Compressor: Columbia Acorn USA, 0.5%

Uranium One: Columbia Acorn International, 0.7%; Columbia Acorn Fund, 0.4%; Columbia Acorn Select, 6.2%

Florida Rock: Columbia Acorn USA, 0.8%; Columbia Acorn Fund, 0.6%

Vulcan Materials: Columbia Acorn Fund, 0.1%

ServiceMaster: Columbia Acorn Fund, 0.4%

Van Houtte: Columbia Acorn International, 0.4%

Highland Hospitality: Columbia Acorn Fund, 0.5%; Columbia Acorn USA, 0.4%

Armor Holdings: Columbia Acorn Fund, 0.3%

Agile Software: Columbia Acorn Fund, 0.1%; Columbia Acorn USA, 0.1%

Cytyc: Columbia Acorn Fund, 0.4%

Crescent Real Estate Equities: Columbia Acorn Fund, 0.1%

Ceridian: Columbia Acorn USA, 1.1%; Columbia Acorn Fund, 0.6%

Penn National Gaming: Columbia Acorn Fund, 0.5%

Genesco: Columbia Acorn USA, 0.3%; Columbia Acorn Fund, 0.2%

Nuveen Investments: Columbia Acorn Fund, 0.4%

Stork: Columbia Acorn International Select, 2.3%; Columbia Acorn International, 1.0%

Chittenden: Columbia Acorn USA, 0.4%; Columbia Acorn Fund, 0.2%

Dobson Communications: Columbia Acorn USA, 1.1%; Columbia Acorn Fund, 0.4%

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. A fund that maintains a relatively concentrated portfolio may be subject to greater risk than a fund that is more fully diversified.

Past performance is no guarantee of future results.

9

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, Rule 12b-1 fees and other Fund expenses. The information on this page is intended to help you understand your ongoing costs of investing in the Columbia Acorn Funds and to compare these costs with the ongoing costs of investing in other mutual funds.

Analyzing your Fund's expenses

To illustrate these ongoing costs, we have provided examples and calculated the expenses paid by investors in the Class A, B and C shares of the Columbia Acorn Funds for the last six months. The information in the following table is based on an initial investment of $1,000.00, 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 ex penses you paid during the reporting period. See the "Compare with other funds" information for details on using the hypothetical data.

January 1, 2007 – June 30, 2007

	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 (%)*
	Actual		Hypothetical		Actual		Hypothetical		Actual		Hypothetical		Actual
Columbia Acorn Fund
Class A		1,000.00		1,000.00		1,113.71		1,019.74		5.35		5.11		1.02
Class B		1,000.00		1,000.00		1,110.48		1,016.86		8.37		8.00		1.60
Class C		1,000.00		1,000.00		1,109.39		1,015.87		9.41		9.00		1.80
Columbia Acorn International
Class A		1,000.00		1,000.00		1,144.11		1,018.89		6.33		5.96		1.19
Class B		1,000.00		1,000.00		1,140.88		1,015.92		9.50		8.95		1.79
Class C		1,000.00		1,000.00		1,139.99		1,015.08		10.40		9.79		1.96
Columbia Acorn USA
Class A		1,000.00		1,000.00		1,093.62		1,018.60		6.49		6.26		1.25
Class B		1,000.00		1,000.00		1,090.20		1,015.57		9.64		9.30		1.86
Class C		1,000.00		1,000.00		1,089.31		1,014.68		10.57		10.19		2.04
Columbia Acorn International Select
Class A		1,000.00		1,000.00		1,116.19		1,017.46		7.77		7.40		1.48
Class B		1,000.00		1,000.00		1,112.62		1,014.38		11.00		10.49		2.10
Class C		1,000.00		1,000.00		1,111.62		1,013.54		11.88		11.33		2.27

10

	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 (%)*
	Actual		Hypothetical		Actual		Hypothetical		Actual		Hypothetical		Actual
Columbia Acorn Select
Class A		1,000.00		1,000.00		1,166.42		1,018.84		6.45		6.01		1.20
Class B		1,000.00		1,000.00		1,162.60		1,015.87		9.65		9.00		1.80
Class C		1,000.00		1,000.00		1,161.81		1,014.93		10.67		9.94		1.99
Columbia Thermostat Fund
Class A		1,000.00		1,000.00		1,042.50		1,022.32		2.53		2.51		.50
Class B		1,000.00		1,000.00		1,039.92		1,019.84		5.06		5.01		1.00
Class C		1,000.00		1,000.00		1,038.28		1,018.60		6.32		6.26		1.25

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

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

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 fees or exchange fees. Therefore, the hypothetical examples provided may not help you determine the relative total costs of owning different funds. If these transaction costs were included, your costs would have been higher.

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

*For the six months ended June 30, 2007.

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, redemption fees or exchange fees.

Estimating your actual expenses

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

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

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

1.  Divide your ending account balance by $1,000.00. 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.

11

Columbia Acorn Fund

In a Nutshell

Charles P. McQuaid

Lead Portfolio Manager

Robert A. Mohn

Co-Portfolio Manager

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

Fund's Positions

in Mentioned Holdings

as of 6/30/07

ITT Educational Services	1.1	%
Eaton Vance	1.1	%
Fugro	1.1	%
People's United	0.8	%
Florida Rock	0.6	%
Penn National Gaming	0.5	%
Highland Hospitality	0.5	%
ESCO Technologies	0.4	%
Hong Kong Exchanges and Clearing	0.4	%
Housing Development Finance	0.4	%
Hexagon	0.4	%
Armor Holdings	0.3	%
Chittenden	0.2	%
Shuffle Master	0.2	%
Crescent Real Estate Equities	0.1	%

Columbia Acorn Fund rose 11.37% (Class A shares, without sales charge) in the first half of 2007, nicely beating the 8.67% return of the small-cap Russell 2500 Index, and also pacing ahead of other benchmarks. The Fund rose 6.60% in the second quarter, moderately outperforming the Russell 2500's gain of 4.94%, and slightly outperforming other benchmarks.

Stock selection drove fine results, and the same three companies were our largest dollar winners for both the first half and the second quarter. ITT Educational Services jumped 77% in the half and 44% in the quarter on strong sales and profit margins. Eaton Vance appreciated 35% in the half and 24% in the quarter; its assets under management surged as the company created new closed-end funds. Netherlands-based Fugro rounded out the winners' circle, up 35% and 27% respectively, on strong demand for energy industry offshore services.

Sellouts also boosted performance. In the first half, Kronos was the Fund's largest dollar winner as a result of takeovers, clocking a 50% gain, while Armor Holdings and Florida Rock were the largest percentage winners, each up about 58%. In the second quarter, Penn National Gaming scored the Fund's largest takeover dollar jackpot and percentage gain, up 42%. There were 27 takeovers in the half, beating the 26 in all of 2006; they boosted performance by over 1.5%. We discuss these takeovers in "Squirrel Chatter II" beginning on Page 5 of this report.

The Fund had relatively low investments in industries that did not perform well. Real estate stocks within the Russell 2500 were down in the first half of 2007, after many stellar years. Columbia Acorn Fund's real estate investment was both relatively small and actually profitable, thanks to announced takeovers of Highland Hospitality and Crescent Real Estate Equities. In the second quarter, Russell 2500 bank and utility stocks also did poorly. The Fund had relatively small investments in both areas.

Columbia Acorn Fund's largest dollar loser in the first half was People's United, a Connecticut savings and loan company. It lost 16% in part due to its somewhat dilutive acquisition of another Fund bank holding, Chittenden, which rose 15%. Shuffle Master dropped 37% in the half due to poor earnings. ESCO Technologies declined 19% in the quarter on news that a major customer of its automatic meter readers was reconsidering its requirements.

Columbia Acorn Fund's international stocks resumed their outperformance in the quarter, and rose 14.56%, boosting their first half gain to 18.85%. In addition to Fugro, mentioned above, top winners for the quarter were Hong Kong Exchanges and Clearing, up 48% on regulatory changes which allow mainland Chinese to own stocks listed in Hong Kong. Housing Development Finance booked a 44% gain on India's prosperity and housing boom. Hexagon, a Swedish manufacturer of measurement equipment and polymers, gained 42% due to excellent earnings. At the end of the half, foreign stocks were 11.5% of Columbia Acorn Fund, up slightly from 11.3% last quarter but down from 13.7% year-to-year.

Small- and mid-cap stocks are often more volatile and less liquid than the stocks of larger companies. Small companies may have a shorter history of operations than larger companies and may have a less diversified product line, making them more susceptible to market pressure. 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 characteristics and holdings.

12

Columbia Acorn Fund (LACAX)

At a Glance

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

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

through June 30, 2007

Inception 10/16/00		Year to date*	1 year	5 years	Life of fund
Returns before taxes	NAV POP	11.37% 4.97	20.32% 13.40	17.63% 16.24	14.32% 13.32
Returns after taxes on distributions	NAV POP	11.15 4.76	18.86 12.02	16.96 15.59	13.38 12.38
Returns after taxes on distributions and sale of fund shares	NAV POP	7.63 3.45	14.85 10.26	15.45 14.19	12.33 11.41
Russell 2500 (pretax)		8.67	18.74	15.30	11.04
S&P 500 (pretax)		6.96	20.59	10.71	3.09

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

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).

*Year to date data not annualized.

Columbia Acorn Fund Portfolio Diversification

as a % of net assets as of 6/30/07

Columbia Acorn Fund Top 10 Holdings

as a % of net assets as of 6/30/07

1.	Coach Designer & Retailer of Branded Leather Accessories	1.6	%
2.	Eaton Vance Specialty Mutual Funds	1.1	%
3.	ITT Educational Services Post-secondary Degree Programs	1.1	%
4.	Abercrombie & Fitch Teen Apparel Retailer	1.1	%
5.	Fugro (Netherlands) Oilfield Services	1.1	%
6.	Expeditors International of Washington International Freight Forwarder	1.1	%
7.	FMC Technologies Oil & Gas Well Head Manufacturer	1.1	%
8.	Chico's FAS Women's Specialty Retailer	1.0	%
9.	Genlyte Group Commercial Lighting Fixtures	1.0	%
10.	Ametek Aerospace/Industrial Instruments	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 $75,000 Investment in Columbia Acorn Fund (Class A)

October 16, 2000 through June 30, 2007

Illustration is based on a hypothetical $75,000 investment from inception in Class A shares of the Fund, which includes a 4.50% maximum initial sales charge for this level of investment. 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: $21,231.3 million

13

Columbia Acorn International

In a Nutshell

P. Zachary Egan

Co-Portfolio Manager

Louis J. Mendes III

Co-Portfolio Manager

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

Fund's Positions

in Mentioned Holdings

as of 6/30/07

Hong Kong Exchanges and Clearing	1.4	%
Hexagon	1.4	%
China Shipping Development	1.0	%
Singapore Exchange	0.8	%
Taewoong	0.6	%
Burckhardt Compression	0.6	%
Lenovo Group	0.5	%
Sung Kwang Bend	0.5	%

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

Columbia Acorn International ended the quarter up 8.53% (Class A shares, without sales charge) vs. a 7.37% gain for the benchmark S&P/Citigroup EMI Global ex-US Index. Year to date, the Fund was up 14.41% vs. a 14.85% gain for the benchmark.

Returns varied considerably by region. Led by Korea and China, the Fund's Asia ex-Japan holdings posted a nearly 32% return on the back of positive earnings surprises and liquidity inflows to the region. Liberalization measures in China allowing local investment companies to invest overseas—with Hong Kong as the most likely initial recipient of these funds—boosted sentiment regarding China–focused companies. China Shipping Development, one of China's largest shipping companies, rose 54% in the quarter and year to date, in part due to its large valuation gap when compared to its domestic-listed shares. Lenovo Group, China's largest computer company, rose nearly 61% in the quarter and was up 45% for the half year on improved earnings and the continued attention towards high profile Chinese companies. The regional exchanges also continued to drive good returns, with Hong Kong Exchanges and Clearing and Singapore Exch ange both jumping 48% in the second quarter as trading volumes increased in what is largely a fixed cost base business. The Fund's top two performers were two niche Korean industrial companies, Sung Kwang Bend and Taewoong. These recent additions to the Fund rose 141% and 103% respectively, in the quarter. Gains were driven by the strong growth in global infrastructure and construction projects, particularly in the Middle East where Korean companies have a long track record in infrastructure development. For the half year, Sung Kwang Bend was up an impressive 285% and Taewoong reached a 104% gain. We applaud our analyst who covers this region, Jeannie Cheung, for ferreting out these ideas.

The Fund's holdings in Continental Europe and Canada also posted strong results, rising 12% and 17%, respectively, in the quarter. Our long-term strategy of investing in what we believe to be high-quality European industrial stocks continued to pay off. Burckhardt Compression, a Swiss supplier of gas compression pumps, and Hexagon, a Swedish manufacturer of measurement equipment and polymers and the Fund's second largest position at the outset of the quarter, both rose over 40% in the second quarter on continued strong demand for their highly specialized products.

Japanese stocks dominated the list of underperformers. Despite a reasonably strong domestic economy, flat wage growth has lead to lackluster domestic consumption as consumers save rather than spend. Moreover, Japanese savers, attracted by higher yields than they can receive at home, are increasingly investing overseas. This has contributed to yen weakness relative to world currencies, placing a further drag on performance.

The other regions of note were the poorly performing British and Irish markets. After posting strong returns in 2006, these markets have seen a strong pullback thus far in 2007 on concerns over higher interest rates, extended valuations and a deepening financial crisis. Since the beginning of 2007, we have significantly reduced our exposure to these markets, but still have been affected by the overall poor sentiment. As a region, the United Kingdom/Ireland was flat in the second quarter.

International investments involve greater potential risks, including less regulation, currency fluctuations, economic instability and political developments. Investments in small- and mid-cap companies may be subject to greater volatility and price fluctuations because they may be thinly traded and less liquid.

14

Columbia Acorn International (LAIAX)

At a Glance

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

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

through June 30, 2007

Inception 10/16/000		Year to date*	1 year	5 years	Life of fund
Returns before taxes	NAV POP	14.41% 7.83	34.52% 26.78	23.96% 22.50	12.47% 11.48
Returns after taxes on distributions	NAV POP	14.31 7.74	32.78 25.15	23.46 22.01	11.64 10.66
Returns after taxes on distributions and sale of fund shares	NAV POP	9.49 5.21	24.50 19.35	21.33 19.98	10.68 9.79
S&P/Citigroup EMI Global ex-US (pretax)		14.85	35.90	26.03	17.17
S&P/Citigroup Global ex-US Cap Range $500mm-$5bn		15.47	35.50	26.22	17.59

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

Investment returns and principal value may fluctuate, resulting in a gain or loss on sale.

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

*Year to date data not annualized.

Columbia Acorn International Portfolio Diversification

as a % of net assets as of 6/30/07

Columbia Acorn International Top 10 Holdings

as a % of net assets as of 6/30/07

1.	Fugro (Netherlands) Oilfield Services	1.6	%
2.	Hong Kong Exchanges and Clearing (Hong Kong) Hong Kong Equity & Derivatives Market Operator	1.4	%
3.	Hexagon (Sweden) Measurement Equipment & Polymers	1.4	%
4.	SES Global (France) Satellite Broadcasting Services	1.2	%
5.	Housing Development Finance (India) Indian Mortgage Lender	1.2	%
6.	Atwood Oceanics (United States) Offshore Drilling Contractor	1.1	%
7.	Suzano (Brazil) Brazilian Pulp & Paper Producer	1.1	%
8.	ShawCor (Canada) Oil & Gas Pipeline Products	1.0	%
9.	Kuehne & Nagel (Switzerland) Freight Forwarding/Logistics	1.0	%
10.	China Shipping Development (China) China's Dominant Shipper for Oil & Coal	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 International (Class A)

October 16, 2000 through June 30, 2007

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. 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:
$5,458.7 million

15

Columbia Acorn USA

In a Nutshell

Robert A. Mohn

Lead Portfolio Manager

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

Fund's Positions

in Mentioned Holdings

as of 6/30/07

ITT Educational Services	2.5	%
FMC Technologies	1.9	%
Atwood Oceanics	1.5	%
ESCO Technologies	1.4	%
Flir Systems	1.2	%
True Religion Apparel	1.1	%
Dobson Communications	1.1	%
II-VI	0.8	%
J. Crew Group	0.6	%
Nektar Therapeutics	0.3	%

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

Columbia Acorn USA gained 5.70% (Class A shares, without sales charge) in the second quarter, outperforming the 4.42% increase of the Russell 2000 Index. The Fund also topped the index year to date through June 30, increasing 9.36% vs. the index's 6.45% gain. A continued underweight in financials contributed to the Fund's outperformance. A victim of deteriorating fundamentals and lingering concerns over credit losses, the financial sector fell 2% in the second quarter and was down more than 6% for the half year in the Russell 2000 Index. Columbia Acorn USA had a 9% weight in financial stocks at quarter end, less than half of the 21% weight in the Russell 2000.

Strong performance of consumer stocks also bolstered the Fund's relative performance. ITT Educational Services, a provider of post-secondary degree programs, was the Fund's leader in the consumer sector and overall. The stock was up 44% for the quarter and 77% year to date on strong student enrollment growth. True Religion Apparel, a maker of high-end denim clothing, gained 25% in the quarter and 33% for the six months on aggressive retail store opening plans. Apparel retailer J. Crew Group was up 35% in the quarter and 40% for the half year thanks to explosive earnings growth of 70% year-over-year.

Other winners included Flir Systems, a manufacturer of infrared cameras. The stock gained 30% in the quarter and was up 45% year to date on news of large contract wins with the U.S. Army. Dobson Communications, a rural cellular service provider, gained 29% in the quarter on speculation that the company would be bought out. On June 29, after the market closed on the last day of the quarter, Dobson did indeed announce they were being acquired by AT&T. For the semiannual period, the stock was up 28%. Atwood Oceanics and FMC Technologies increased due to healthy demand for deep-water drilling contractors (Atwood Oceanics) and oil and gas well head manufacturers (FMC Technologies). Atwood gained 17% in the quarter and was up 40% for the half year while FMC Technologies posted a 14% quarterly gain and 29% year-to-date return.

Laggards included ESCO Technologies, a maker of automated electric meter readers. The stock fell 19% in the quarter and was off 20% for the six months on news of possible changes in a large contract with a California utility. II-VI, a maker of laser components, fell 20% in the quarter due to operational difficulties. Year-to-date the company is showing less than a 3% loss.

Two biotech names also landed in the loser column. The Medicines Company, a maker of cardiovascular drugs, fell 23% in the quarter and was off 39% for the half year as an appeal to extend one of its major drug patents was denied. We sold the stock. Nektar Therapeutics, a provider of drug delivery technologies, fell 27% in the quarter and was off 38% for the six months as sales of the company's inhaleable insulin came in under expectations.

While certain sectors, such as housing, have been under a lot of pressure so far this year, we believe the overall economy remains remarkably healthy. We feel the market is continuing to offer plenty of investment opportunities for discriminating small-cap investors.

Risks include stock market fluctuations due to economic and business developments. Investments in small- and mid-cap companies may be subject to greater volatility and price fluctuations because they may be thinly traded and less liquid.

16

Columbia Acorn USA (LAUAX)

At a Glance

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

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

through June 30, 2007

Inception 10/16/00		Year to date*	1 year	5 years	Life of fund
Returns before taxes	NAV POP	9.36% 3.07	15.69% 9.04	14.73% 13.38	14.05% 13.05
Returns after taxes on distributions	NAV POP	9.22 2.94	15.23 8.61	14.43 13.09	13.80 12.80
Returns after taxes on distributions and sale of fund shares	NAV POP	6.29 2.19	10.77 6.41	12.93 11.71	12.45 11.53
Russell 2000 (pretax)		6.45	16.43	13.88	9.94

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

Investment returns and principal value may fluctuate, resulting in a gain or loss on sale.

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

*Year to date data not annualized.

Columbia Acorn USA Portfolio Diversification

as a % of net assets as of 6/30/07

Columbia Acorn USA Top 10 Holdings

as a % of net assets as of 6/30/07

1.	ITT Educational Services Post-secondary Degree Programs	2.5	%
2.	Genlyte Group Commercial Lighting Fixtures	2.2	%
3.	Crown Castle International Communications Towers	2.1	%
4.	FMC Technologies Oil & Gas Well Head Manufacturer	1.9	%
5.	Time Warner Telecom Fiber Optic Telephone/Data Services	1.8	%
6.	AmeriCredit Auto Lending	1.7	%
7.	Abercrombie & Fitch Teen Apparel Retailer	1.7	%
8.	Edwards Lifesciences Heart Valves	1.7	%
9.	Oxford Industries Branded & Private Label Apparel	1.7	%
10.	Tellabs Telecommunications Equipment	1.6	%

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

The Growth of a $75,000 Investment in Columbia Acorn USA (Class A)

October 16, 2000 through June 30, 2007

Illustration is based on a hypothetical $75,000 investment from inception in Class A shares of the Fund, which includes a 4.50% maximum initial sales charge for this level of investment. 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:
$1,703.5 million

17

Columbia Acorn International Select

In a Nutshell

Christopher J. Olson

Lead Portfolio Manager

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

Fund's Positions

in Mentioned Holdings

as of 6/30/07

Nintendo	4.9	%
Potash Corp. of Saskatchewan	3.2	%
Hong Kong Exchanges and Clearing	3.2	%
Hexagon	2.7	%
Kenedix	2.3	%
Singapore Exchange	1.8	%
C&C Group	0.1	%

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

Columbia Acorn International Select climbed 7.31% (Class A shares, without sales charge) in the second quarter, outpacing the 6.08% gain of the S&P/Citigroup World ex-US Cap Range $2-10B Index. Year to date, the Fund was up 11.62% vs. a 12.04% return for the index.

Japan's Nintendo continued to post strong returns in the second quarter, increasing 27%. For the first six months of the year, the stock was up 49% as sales of its Wii gaming system continue to break records and strong sales of its gaming software followed suit. Canada's Potash Corp. of Saskatchewan, the worlds' largest producer of potash, gained 48% in the quarter and was up 65% for the half year as increasing crop prices bode well for fertilizer prices. Sweden's Hexagon, a manufacturer of measurement equipment and polymers, increased 42% in the quarter and 35% for the six months on strong earnings news.

Increased liquidity and favorable earnings news boosted the performance of Asian markets, excluding Japan. The Fund's equity and derivatives market operators, Hong Kong Exchanges and Clearing and Singapore Exchange, both benefited from increased trading volumes. Hong Kong Exchanges and Clearing increased nearly 48% in the quarter and was up 32% for the half year. Singapore Exchange saw similar gains for the quarter, up 48%, and for the six months the stock was up 76%.

Laggards for the quarter included Kenedix, a Japanese real estate investment management company. The stock fell 27% in the quarter and was off 18% for the first half of the year due to the rise in interest rates in Japan and concerns that the real estate sector would suffer. Banca Italease, an Italian leasing and factoring company, fell 46% in the quarter and was sold out of the Fund as the company seriously misjudged the amount of exposure it had to interest rate derivatives, which could result in a required capital increase for the firm. Last year Irish beverage company C&C Group was a star performer for Columbia Acorn International Select but the stock has cooled in 2007. Company earnings and sales have declined due to increased competition and very poor summer weather. The stock fell 8% in the quarter and was down 21% year to date.

International investments involve greater potential risks, including less regulation, currency fluctuations, economic instability and political developments. Investments in small- and mid-cap companies may be subject to greater volatility and price fluctuations because they may be thinly traded and less liquid.

18

Columbia Acorn International Select (LAFAX)

At a Glance

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

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

through June 30, 2007

Inception 10/16/00		Year to date*	1 year	5 years	Life of fund
Returns before taxes	NAV POP	11.62% 5.20	34.62% 26.88	21.58% 20.15	9.00% 8.04
Returns after taxes on distributions	NAV POP	11.52 5.11	34.60 26.86	21.61 20.18	9.00 8.04
Returns after taxes on distributions and sale of fund shares	NAV POP	7.55 3.38	22.59 17.56	19.29 17.98	7.93 7.07
S&P/Citigroup World ex-US Cap Range $2-10B (pretax)		12.04	29.92	22.67	15.04

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

Investment returns and principal value may fluctuate, resulting in a gain or loss on sale.

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

*Year to date data not annualized.

Columbia Acorn International Select Portfolio Diversification

as a % of net assets as of 6/30/07

Columbia Acorn International Select Top 10 Holdings as a % of net assets as of 6/30/07

1.	Nintendo (Japan) Entertainment Software & Hardware	4.9	%
2.	Fugro (Netherlands) Oilfield Services	3.6	%
3.	CRH (Ireland) Global Building Materials	3.3	%
4.	Hong Kong Exchanges and Clearing (Hong Kong) Hong Kong Equity & Derivatives Market Operator	3.2	%
5.	Zumtobel (Austria) Lighting Systems	3.2	%
6.	Potash Corp. of Saskatchewan (Canada) World's Largest Producer of Potash	3.2	%
7.	Atwood Oceanics (United States) Offshore Drilling Contractor	3.1	%
8.	Synthes (Switzerland) Products for Orthopedic Surgery	3.1	%
9.	Smith & Nephew (United Kingdom) Medical Equipment & Supplies	3.0	%
10.	SES Global (France) Satellite Broadcasting Services	2.9	%

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 Select (Class A)

October 16, 2000 through June 30, 2007

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 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:
$222.0 million

19

Columbia Acorn Select

In a Nutshell

Ben Andrews

Lead Portfolio Manager

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

Fund's Positions

in Mentioned Holdings

as of 6/30/07

ITT Educational Services	4.8	%
Liberty Global	4.4	%
Potash Corp. of Saskatchewan	3.5	%
Tetra Technologies	1.8	%
American Commercial Lines	1.7	%
JB Hunt Transport Services	0.9	%

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

Columbia Acorn Select gained 9.05% (Class A shares, without sales charge) in the second quarter, ahead of its benchmark, the S&P MidCap 400 Index, which returned 5.84%. The Fund also topped the S&P 500's return of 6.28% in the quarter. Year to date, Columbia Acorn Select was up 16.64% vs. 11.98% for the S&P MidCap 400 and 6.96% for the S&P 500.

The top three drivers of Fund performance were the same this quarter as last quarter: ITT Educational Services, Potash Corp. of Saskatchewan and Liberty Global. All three companies displayed strong fundamentals and their combined return accounted for 4.7% of the Fund's 16.64% return year to date.

We made a few structural adjustments to Columbia Acorn Select during the quarter. The minimum dollar amount to open a new account is now $100,000, up from $50,000, and all retirement plans are now subject to the new minimum. We currently manage about $3.2 billon in assets in Columbia Acorn Select. Cash inflows have been very strong so far this year and we hope to temper this with the higher minimum. At the end of the period, the Fund had 10% of its assets in cash. We are finding ideas to buy, however most are valued at levels that we are willing to pay to build a small position but we don't want to bet the ranch, at least not yet. We do not want to be forced into initiating bigger positions just to accommodate cash inflows. While we don't believe we are reaching capacity with this product in the long run, we would like to be prudent in the short term.

We also increased the number of stocks we are allowed to hold in the Fund. Columbia Acorn Select can now invest in generally 30 to 60 companies (currently we hold 39), an increase from the previous 20 to 40. We still plan on running a select portfolio. Since starting the Fund in 1998, we have had over 40% of our assets in our top 10 names and we don't see this changing. We also slightly increased the percentage of the Fund that we can invest in foreign companies. Currently we have approximately 10% of the Fund's assets invested in international stocks, mostly in the raw materials sector.

We added three stocks to the portfolio during the quarter: American Commercial Lines, JB Hunt Transport Services and Tetra Technologies. We sold out of two positions, Nuveen Investments and Weight Watchers International.

We sold Nuveen one month before it announced it was selling itself to a private equity firm. Our crystal ball was smudged and we did not see the take out coming, but should we have? We sold Nuveen because we were concerned with the direction it was taking with its asset management division. We believe Nuveen was purchased at a much higher price than we sold it at because money has been abundant and private equity can leverage cheap money and pay lofty multiples while infusing little equity. The Nuveen sale prompted me to go back and look at our other sales since I became portfolio manager of the Fund in early 2004. We exited 22 positions and had another three companies taken over for cash during the last three years. Looking back at the reasons we had for selling the positions, we were often right yet many of these stocks trade at higher prices. This exercise reminded us how easily mistakes are forgiven in bull markets; companie s can miss earnings estimates and growth can come in slower than Wall Street originally thought yet share prices can still go up. This is true for portfolio managers as well; most of us are putting up large returns during this period but will we keep these returns when the economy goes slack? When the market does cool, we believe owning the right stocks will be very important and having more structural flexibility within the Fund should help us to preserve capital. Thank you for your continued support of 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.

20

Columbia Acorn Select (LTFAX)

At a Glance

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

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

through June 30, 2007

Inception 10/16/000		Year to date*	1 year	5 years	Life of fund
Returns before taxes	NAV POP	16.64% 9.93	32.17% 24.57	18.06% 16.67	14.54% 13.54
Returns after taxes on distributions	NAV POP	16.46 9.77	31.60 24.03	17.74 16.36	14.26 13.26
Returns after taxes on distributions and sale of fund shares	NAV POP	10.89 6.53	21.38 16.42	15.88 14.62	12.84 11.92
S&P MidCap 400 (pretax)		11.98	18.51	14.17	10.28

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

Investment returns and principal value may fluctuate, resulting in a gain or loss on sale.

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

*Year to date data not annualized.

Columbia Acorn Select Portfolio Diversification

as a % of net assets as of 6/30/07

Columbia Acorn Select Top 10 Holdings

as a % of net assets as of 6/30/07

1.	Uranium One (South Africa) (previously UrAsia Energy) Uranium Mines in South Africa, Kazakhstan, Australia & the U.S.	6.2	%
2.	ITT Educational Services Post-secondary Degree Programs	4.8	%
3.	Tellabs Telecommunications Equipment	4.6	%
4.	Liberty Global Cable TV Franchises outside the USA	4.4	%
5.	Conseco Life, Long-term Care & Medical Supplement Insurance	4.3	%
6.	Safeway Supermarkets	3.8	%
7.	Abercrombie & Fitch Teen Apparel Retailer	3.8	%
8.	Janus Capital Group Manages Mutual Funds	3.5	%
9.	Potash Corp. of Saskatchewan (Canada) World's Largest Producer of Potash	3.5	%
10.	Expedia Online Travel Services Company	3.2	%

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 $100,000 Investment in Columbia Acorn Select (Class A)*

October 16, 2000 through June 30, 2007

Illustration is based on a hypothetical $100,000 investment from inception in Class A shares of the Fund, which includes a 3.50% maximum initial sales charge for this level of investment. 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:
$3,206.1 million

* The minimum initial investment amount for Columbia Acorn Select was increased to $100,000 on June 25, 2007. Certain exclusions may apply.

21

Columbia Thermostat Fund

In a Nutshell

Charles P. McQuaid

Lead Portfolio Manager

Performance data quoted represents past performance and current performance may be lower or higher. Past performance is no guarantee of future results. The investment return and principal value of an investment in the Fund will fluctuate so that shares, when redeemed, may be worth more or less than the original cost. Performance may reflect any voluntary waivers or reimbursements of fund expenses by the Adviser or its affiliates. Absent these waivers, or reimbursement arrangements, performance results may be lower. Visit columbiafunds.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 ended the second quarter up 1.98% (Class A shares, without sales chage) and posted a 4.25% year-to-date gain. Fund performance, as expected, was between the S&P 500 Index and the Lehman Brothers U.S. Credit Intermediate Bond Index for both time periods (see Page 4 for index data).

Fund returns came in below the 4.96% quarterly gain and 6.79% six-month increase of the Lipper Flexible Portfolio Funds Index. Key to its investment strategy, Columbia Thermostat Fund sells a portion of its stock funds when the S&P 500 goes up and invests more in bonds. Because 2007 has generally been a strong year for equities, Columbia Thermostat Fund has had more of its portfolio in bonds than the average fund in the Lipper Flexible Portfolio Funds Index. This dampened the Fund's relative returns in the first six months of this year. However, if the equity weakness that arose just following the period end persists, Columbia Thermostat Fund's relative performance is likely to improve. Additionally, our approach should automatically ensure that we are buying equities if there is a sustained drop in prices. At the end of the period, the Fund had a 35% exposure to stocks and a 65% exposure to bonds.

As the following table illustrates, the equity portion of the portfolio had impressive gains in the quarter and year to date through June 30, 2007. For the second quarter, the Fund's equity component was up 6.70% and, for the half year, it was up 9.71%. Columbia Acorn Select posted top gains for both time periods, followed by Columbia Acorn International and Columbia Acorn Fund. On the fixed income side, the Fund's income component was down 0.70% for the quarter and gained just 0.75% for the half year.

Results of the Funds Owned in Columbia Thermostat Fund

at June 30, 2007

Equities Fund	Weightings in Category			2nd quarter returns			Year-to-date returns to 6/30/07
Columbia Acorn Fund Z		15	%		6.70	%		11.55	%
Columbia Acorn Select Z		10	%		9.12	%		16.76	%
Columbia Marsico Growth Fund		15	%		5.34	%		6.01	%
Columbia Acorn International Z		15	%		8.61	%		14.59	%
Columbia Dividend Income Fund		20	%		5.69	%		7.88	%
Columbia Large Cap Enhanced Core Fund		25	%		6.17	%		6.60	%
Weighted Average Equity Return		100	%		6.70	%		9.71	%
Fixed Income Fund	Weightings in Category			2nd quarter returns			Year-to-date returns to 6/30/07
Columbia Federal Securities Fund		30	%		-1.06	%		0.28	%
Columbia Intermediate Bond Fund		50	%		-0.52	%		0.77	%
Columbia Conservative High Yield Fund		20	%		-0.64	%		1.42	%
Weighted Average Income Return		100	%		-0.70	%		0.75	%

Columbia Thermostat Fund Rebalancing in the Second Quarter

April 16, 2007:	35% stock, 65% bond
May 4, 2007:	30% stock, 70% bond
June 8, 2007:	35% stock, 65% bond

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 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. Small- and mid-cap stocks are often more volatile and less liquid than the stocks of larger companies. Small companies may have a shorter history of operations than larger companies and may have a less diversified product line, making them more susceptible to market pressure. International investments involve greater potential risks, including less regulation, currency fluctuations, economic instability and political developments. Changes in interest rates and changes in the financial strength of issu ers of lower-rated bonds may also affect underlying fund performance. The Fund is also subject to the risk that the investment adviser's decisions regarding asset classes and 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.

22

Columbia
Thermostat Fund (CTFAX)

At a Glance

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

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

through June 30, 2007

Inception 3/3/03		Year to date*	1 year	3 years	Life of fund
Returns before taxes	NAV POP	4.25% -1.75	12.58% 6.11	8.77% 6.65	11.88% 10.36
Returns after taxes on distributions	NAV POP	3.78 -2.19	10.21 3.87	6.87 4.78	10.43 8.93
Returns after taxes on distributions and sale of fund shares	NAV POP	3.20 -0.72	9.42 5.14	6.79 4.97	9.74 8.40
S&P 500 (pretax)		6.96	20.59	11.68	16.42
Lehman Brothers U.S. Credit Intermediate Bond Index (pretax)		1.28	6.34	3.79	3.70
Lipper Flexible Portfolio Funds Index (pretax)		6.79	16.83	11.10	14.13

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

Investment returns and principal value may fluctuate, resulting in a gain or loss on sale.

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

*Year to date data not annualized.

Columbia Thermostat Fund Asset Allocation

as a % of net assets as of 6/30/07

Columbia Thermostat Fund Portfolio Weightings

as a % of assets in each investment category
as of 6/30/07

Stock Mutual Funds

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

Bond Mutual Funds

Columbia Intermediate Bond Fund	50	%
Columbia Federal Securities Fund	30	%
Columbia Conservative High Yield Fund	20	%

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

March 3, 2003 through June 30, 2007

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. 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:
$180.0 million

23

Columbia Acorn Fund

Major Portfolio Changes in the Second Quarter (Unaudited)

	Number of Shares
	03/31/07		06/30/07
Additions
Information
Blackbaud		0		613,000
Ciena		0		370,000
Dolby Laboratories		0		250,000
Epicor		671,000		1,500,000
Equinix		190,000		225,000
Everlight Electronics (Taiwan)		3,198,000		6,400,000
FARO Technologies		685,000		860,000
II-VI		2,025,000		2,220,000
Informa Group (United Kingdom)		0		1,300,000
IPG Photonics		750,000		1,190,000
Kenexa		962,000		1,200,000
MetroPCS Communications		0		175,000
Microsemi		1,925,000		2,250,000
Polycom		1,060,000		1,250,000
Red Hat		0		900,000
Sanmina-SCI		10,000,000		14,522,000
Scientific Games		500,000		2,000,000
Switch & Data Facilities		370,000		877,000
Taylor Nelson Sofres (United Kingdom)		0		2,358,000
Tellabs		14,100,000		15,380,000
TheStreet.com		0		1,094,000
Time Warner Telecom		4,700,000		6,200,000
Trimble Navigation		2,900,000		3,070,000
Industrial Goods & Services
Albany International		234,000		700,000
American Commercial Lines		0		1,900,000
American Reprographics		1,500,000		2,000,000
Cytec Industries		0		400,000
Donaldson		3,800,000		4,000,000
Interline Brands		500,000		1,000,000
Intertek Testing (United Kingdom)		0		631,000
Kansai Paint (Japan)		0		124,000
Stork (Netherlands)		0		56,492
Union Tool (Japan)		44,300		360,000
Vulcan Materials		0		175,000
Wavin (Netherlands)		90,000		611,460
Consumer Goods & Services
Ambassadors Group		0		135,000
Hansen Natural		850,000		1,650,000
Herman Miller		2,500,000		3,800,000
NutriSystem		1,000,000		1,120,000
Thor Industries		441,000		561,000

	Number of Shares
	03/31/07		06/30/07
Finance
BOK Financial		2,605,000		2,852,000
CAI International		0		200,000
Conseco		4,000,000		5,000,000
First Financial Bankshares		286,000		386,000
HCC Insurance Holdings		3,125,000		3,600,000
MB Financial		0		700,000
Philadelphia Consolidated Holding		2,040,000		2,390,000
TriCo Bancshares		0		200,000
West Bancorporation		1,049,000		1,249,000
Energy & Minerals
Carrizo Oil & Gas		0		1,100,000
Dresser-Rand Group		0		552,000
Fugro (Netherlands)		3,418,301		3,584,037
SBM Offshore (Netherlands)		0		250,000
Tesco		190,000		1,044,000
Tetra Technologies		1,228,000		1,988,000
Health Care
Arena Pharmaceuticals		1,179,000		1,320,000
BioMarin		2,375,000		3,940,000
Collagenex Pharmaceuticals		1,000,000		1,200,000
Eresearch Technology		2,600,000		3,000,000
Healthcare Services Group		0		400,000
OPG Groep (Netherlands)		270,000		1,080,000
Pharmacopeia		0		825,000
QIAGEN		0		900,000
Seattle Genetics		3,300,000		3,720,000
Other Industries
Gaylord Entertainment		1,760,000		2,000,000
Jiangsu Expressway (China)		0		6,790,000

24

	Number of Shares
	03/31/07		06/30/07
Sales
Information
Activision		1,000,000		750,000
Advantech (Taiwan)		9,956,115		8,157,000
Alltel		1,200,000		0
Avnet		3,105,000		2,490,000
Cubic		273,000		0
Fair Isaac		916,000		0
Gemstar-TV Guide International		8,000,000		0
infoUSA		1,450,000		800,000
Jabil Circuit		1,320,000		690,000
JDA Software		1,490,000		0
Kronos		2,750,000		0
Liberty Media Corp-Interactive		655,000		0
NAVTEQ		1,400,000		1,200,000
Openwave Systems		2,500,000		1,500,000
Seachange International		964,000		0
SRA International		1,350,000		1,050,000
Supertex		950,000		820,000
TALX		865,000		0
THQ		2,300,000		2,000,000
WebEx		353,000		0
Industrial Goods & Services
Gardner Denver		350,000		0
Grafton Group (Ireland)		1,600,000		0
K&F Industries		1,712,000		0
Neopost (France)		140,000		112,000
Quanta Services		2,500,000		2,200,000
UTI Worldwide		3,000,000		2,700,000
Worthington Industries		1,800,000		1,500,000
Consumer Goods & Services
C&C Group (Ireland)		800,000		26,000
Central Parking		1,168,000		0
Ducati Motor (Italy)		5,700,000		5,410,390
Edgars Consolidated Stores (South Africa)		3,500,000		0
Fleetwood Enterprises		3,255,000		2,500,000
HNI		2,550,000		2,236,000
ITT Educational Services		2,250,000		2,000,000
Regis		800,000		0
Techtronic Industries (Hong Kong)		14,999,300		0
Williams-Sonoma		250,000		0
Winnebago		540,000		390,000

	Number of Shares
	03/31/07		06/30/07
Finance
Anchor Bancorp Wisconsin		1,178,000		978,000
Anglo Irish Bank (Ireland)		1,800,000		0
Banca Italease (Italy)		250,000		0
East West Bancorp		200,000		0
Northern Rock (United Kingdom)		2,500,000		0
Nuveen Investments		2,157,000		1,303,000
Paragon Group (United Kingdom)		1,000,000		0
RLI		570,000		0
SY Bancorp		48,000		0
Energy & Minerals
Key Energy Services		730,000		170,000
McMoran Exploration		870,000		470,000
Newpark Resources		310,000		0
St. Mary Land & Exploration		850,000		500,000
Vaalco Energy		3,200,000		2,750,000
Health Care
Cytokinetics		2,000,000		0
Dendrite International		1,433,000		0
Nuvelo		1,650,000		1,025,000
The Medicines Company		600,000		0
United Surgical Partners		1,150,000		0
Viasys Healthcare		1,200,000		0
Other Industries
DiamondRock Hospitality		3,700,000		3,500,000

25

Columbia Acorn Fund

Statement of Investments (Unaudited), June 30, 2007

Number of Shares			Value (000)
				Equities: 93.6%
Information 23.6%
		> Business Software 3.3%
	12,000,000	Novell (a)	$	93,480
		Directory, Operating System & Identity Management Software
	1,400,000	Micros Systems (a)		76,160
		Information Systems for Restaurants & Hotels
	3,300,000	Parametric Technology (a)		71,313
		Engineering Software & Services
	1,800,000	Avid Technology (a)		63,630
		Digital Nonlinear Editing Software & Systems
	4,000,000	Informatica (a)		59,080
		Enterprise Data Integration Software
	2,131,000	Concur Technologies (a)(b)		48,693
		Web Enabled Cost & Expense Management Software
	1,200,000	Kenexa (a)		45,252
		Recruiting and Workforce Management Solutions
	6,000,000	Actuate (a)(b)		40,740
		Information Delivery Software & Solutions
	1,800,000	Cadence Design Systems (a)		39,528
		Electronic Design Automation Software
	2,500,000	Radiant Systems (a)(b)		33,100
		Point of Sale Systems: Convenient Stores & Restaurants
	3,000,000	Lawson Software (a)		29,670
		Enterprise Resource Planning (ERP) Software
	3,500,000	Agile Software (a)(b)		28,210
		Product Design Software
	1,500,000	Epicor (a)		22,305
		Software Systems to Run Small Businesses
	900,000	Red Hat (a)		20,052
		Maintenance & Support for Opensource
	613,000	Blackbaud		13,535
		Software & Services for Non-Profits
	3,500,000	Tumbleweed Communications (a)(b)		8,925
		Email Content Security & File Transfer Management
				693,673
		> Computer Hardware & Related Equipment 3.0%
	3,800,000	Amphenol		135,470
		Electronic Connectors
	2,090,000	Belden CDT		115,681
		Specialty Cable
	2,220,000	II-VI (a)(b)		60,317
		Laser Components
	1,426,000	Nice Systems (Israel) (a)		49,539
		Audio & Video Recording Solutions
	460,000	Wincor Nixdorf (Germany)		42,636
		Retail POS Systems & ATM Machines
	860,000	Zebra Technologies (a)		33,316
		Bar Code Printers
	900,000	Netgear (a)		32,625
		Networking Products for Small Business & Home
	1,027,000	Avocent (a)		29,793
		Computer Control Switches
	8,157,000	Advantech (Taiwan)		26,050
		Embedded Computers

Number of Shares			Value (000)
	620,000	Rogers (a)	$	22,940
		PCB Laminates & High-performance Foams
	735,000	Excel Technology (a)(b)		20,536
		Laser Systems & Electro-optical Components
	375,000	Diebold		19,575
		Automated Teller Machines
	1,310,000	CTS		16,585
		Electronic Components, Sensors & Electronics Manufacturing Solutions
	325,000	Stratasys (a)		15,269
		Rapid Prototyping Systems
	500,000	Intermec (a)		12,655
		Bar Code & Wireless LAN Systems
	250,000	Dolby Laboratories (a)		8,853
		Audio Technology for Consumer Electronics
				641,840
		> Mobile Communications 2.1%
	4,500,000	Crown Castle International (a)		163,215
		Communications Towers
	3,500,000	American Tower (a)		147,000
		Communications Towers in USA & Mexico
	8,000,000	Dobson Communications (a)(b)		88,880
		Rural & Small City Cellular Telephone Services
	600,000	Telephone & Data Systems		37,542
		Cellular & Wireline Telephone Services
	1,500,000	Openwave Systems		9,390
		Internet Software for Mobile Devices
	600,000	Globalstar (a)		6,210
		Satellite Mobile Voice & Data Carrier
	175,000	MetroPCS Communications (a)		5,782
		Discount Cellular Telephone Services
				458,019
		> Instrumentation 2.1%
	2,800,000	Flir Systems (a)		129,500
		Infrared Cameras
	3,070,000	Trimble Navigation (a)		98,854
		GPS-based Instruments
	750,000	Mettler Toledo (a)		71,632
		Laboratory Equipment
	800,000	Varian (a)		43,864
		Analytical Instruments
	600,000	Dionex (a)		42,594
		Ion & Liquid Chromatography
	860,000	FARO Technologies (a)(b)		27,400
		Precision Measurement Equipment
	1,190,000	IPG Photonics (a)		23,741
		Fiber Lasers
				437,585
		> CATV 1.6%
	4,500,000	Discovery Holding (a)		103,455
		CATV Programming
	2,050,000	Liberty Global Series C (a)		80,565
	1,500,000	Liberty Global Series A (a)		61,560
		Cable TV Franchises Outside the USA
	70,000	Jupiter Telecommunications (Japan) (a)		57,722
		Largest Cable Service Provider in Japan
	130,000	Liberty Media Corp - Capital (a)		15,298
		CATV Holding Company

26

Number of Shares			Value (000)
		> CATV—continued
	1,250,000	Mediacom Communications (a)	$	12,113
		Cable Television Franchises
				330,713
		> Semiconductors & Related Equipment 1.5%
	4,800,000	Integrated Device Technology (a)		73,296
		Communications Semiconductors
	2,250,000	Microsemi (a)		53,887
		Analog/Mixed Signal Semiconductors
	4,425,000	Entegris (a)		52,569
		Semiconductor Wafer Shipping & Handling Products
	1,270,000	Littelfuse (a)(b)		42,888
		Little Fuses
	3,257,000	AMIS Holdings (a)		40,777
		Mixed-signal Semiconductors
	820,000	Supertex (a)(b)		25,699
		Mixed-signal Semiconductors
	6,400,000	Everlight Electronics (Taiwan)		22,868
		A Led Packager
	1,905,000	IXYS (a)(b)		15,907
		Power Semiconductors
				327,891
		> Gaming Equipment & Services 1.4%
	2,750,000	International Game Technology		109,175
		Slot Machines & Progressive Slots
	3,150,000	Bally Technologies (a)(b)		83,223
		Slot Machines & Software
	2,000,000	Scientific Games (a)		69,900
		Lottery Services Provider
	2,430,000	Shuffle Master (a)(b)		40,338
		Card Shufflers & Casino Games
				302,636
		> Internet Related 1.4%
	3,000,000	ValueClick (a)		88,380
		Internet Advertising
	9,500,000	SkillSoft (a)(b)		88,255
		Web-based Learning Solutions (E-Learning)
	4,000,000	CNET Networks (a)		32,760
		Internet Advertising on Niche Websites
	1,000,000	Sohu.com (China) (a)		31,990
		Advertising on Chinese Internet Portal
	225,000	Equinix (a)		20,581
		Network Neutral Data Centers
	877,000	Switch & Data Facilities (a)		16,829
		Network Neutral Data Centers
	1,094,000	TheStreet.com		11,903
		Financial Information Website Publisher
				290,698
		> Financial Processors 1.1%
	2,774,000	Global Payments		109,989
		Credit Card Processor
	6,500,000	Hong Kong Exchanges and Clearing (Hong Kong)		91,966
		Hong Kong Equity & Derivatives Market Operator
	5,000,000	Singapore Exchange (Singapore)		31,933
		Singapore Equity & Derivatives Market Operator
				233,888

Number of Shares			Value (000)
		> Telecommunications Equipment 1.1%
	15,380,000	Tellabs (a)	$	165,489
		Telecommunications Equipment
	1,250,000	Polycom (a)		42,000
		Video Conferencing Equipment
	370,000	Ciena (a)		13,368
		Optical Transport & Broadband Access Equipment
	1,510,000	Symmetricom (a)		12,684
		Network Timing & Synchronization Devices
				233,541
		> Business Information & Marketing Services 1.1%
	3,460,000	Ceridian (a)		121,100
		HR Services & Payment Processing
	2,300,000	Navigant Consulting (a)		42,688
		Financial Consulting Firm
	2,000,000	ProQuest (b)		19,080
		Education Services for the K-12 Market
	420,000	FTI Consulting (a)		15,973
		Financial Consulting Firm
	250,000	Getty Images (a)		11,952
		Photographs for Publications & Electronic Media
	2,358,000	Taylor Nelson Sofres (United Kingdom)		11,152
		Market Research
	800,000	infoUSA		8,176
		Business Data for Sales Leads
				230,121
		> Telephone Services 0.9%
	6,200,000	Time Warner Telecom (a)		124,620
		Fiber Optic Telephone/Data Services
	1,300,000	Cogent Communications (a)		38,831
		Internet Data Pipelines
	1,400,000	Windstream		20,664
		Rural Telephone Franchises
				184,115
		> Electronics Distribution 0.5%
	2,490,000	Avnet (a)		98,704
		Electronic Components Distribution
	710,000	Agilysys		15,975
		IT Distributor
				114,679
		> Contract Manufacturing 0.4%
	14,522,000	Sanmina-SCI (a)		45,454
		Electronic Manufacturing Services
	1,020,000	Plexus (a)		23,450
		Electronic Manufacturing Services
	690,000	Jabil Circuit		15,228
		Electronic Manufacturing Services
				84,132
		> Computer Services 0.4%
	5,000,000	iGate (a)(b)		40,100
		IT & Business Process Outsourcing Services
	1,050,000	SRA International (a)		26,523
		Government IT Services
	4,600,000	AnswerThink (a)(b)		16,652
		IT Integration & Best Practice Research
				83,275

27

Columbia Acorn Fund

Statement of Investments (Unaudited), continued

Number of Shares			Value (000)
		> Consumer Software 0.3%
	2,000,000	THQ (a)	$	61,040
		Entertainment Software
	750,000	Activision (a)		14,002
		Entertainment Software
				75,042
		> Television Programming 0.3%
	4,000,000	Lions Gate Entertainment (a)		44,120
		Film & TV Studio
	433,900	Alliance Atlantis Communication (Canada) (a)		21,299
		CATV Channels, TV/Movie Production/ Distribution
				65,419
		> Publishing 0.3%
	1,200,000	NAVTEQ (a)		50,808
		Map Data for Electronic Devices
	1,300,000	Informa Group (United Kingdom)		14,451
		Global Publisher & Event Organizer
				65,259
		> Satellite Broadcasting & Services 0.3%
	2,755,000	SES Global (France)		59,384
		Satellite Broadcasting Services
				59,384
		> Radio 0.3%
	1,541,000	Salem Communications (b)		17,090
		Radio Stations for Religious Programming
	1,500,000	Cumulus Media (a)		14,025
		Radio Stations in Small Cities
	1,400,000	Saga Communications (a)(b)		13,720
		Radio Stations in Small- & Mid- Sized Cities
	2,400,000	Spanish Broadcasting System (a)(b)		10,320
		Spanish Language Radio Stations
				55,155
		> TV Broadcasting 0.2%
	2,500,000	Entravision Communications (a)		26,075
		Spanish Language TV, Radio & Outdoor
	1,750,000	Gray Television		16,222
		Mid Market Affiliated TV Stations
				42,297
Information: Total				5,009,362
Industrial Goods & Services 18.1%
		> Machinery 5.5%
	5,000,000	Ametek		198,400
		Aerospace/Industrial Instruments
	4,000,000	Donaldson (b)		142,200
		Industrial Air Filtration
	3,500,000	Clarcor (b)		131,005
		Mobile & Industrial Filters
	2,850,000	Pentair		109,924
		Pumps & Water Treatment
	2,300,000	Pall		105,777
		Filtration & Fluids Clarification
	1,900,000	Mine Safety Appliances (b)		83,144
		Safety Equipment

Number of Shares			Value (000)
	2,200,000	ESCO Technologies (b)	$	79,772
		Automatic Electric Meter Readers
	1,300,000	Kaydon		67,756
		Specialized Friction & Motion Control Products
	750,000	Armor Holdings (a)		65,153
		Military Trucks, Armor & Helmets
	1,250,000	Nordson		62,700
		Dispensing Systems for Adhesives & Coatings
	833,000	Toro		49,055
		Turf Maintenance Equipment
	2,100,000	Goodman Global (a)		46,662
		HVAC Equipment Manufacturer
	112,000	Neopost (France)		16,380
		Postage Meter Machines
	360,000	Union Tool (Japan)		13,299
		Precision Drill Bit Manufacturer
				1,171,227
		> Other Industrial Services 3.1%
	5,500,000	Expeditors International of Washington		227,150
		International Freight Forwarder
	2,700,000	UTI Worldwide		72,333
		Global Logistics & Freight Forwarding
	1,900,000	Forward Air (b)		64,771
		Freight Transportation Between Airports
	2,000,000	American Reprographics (a)		61,580
		Document Management & Logistics
	1,750,000	Mobile Mini (a)		51,100
		Portable Storage Units Leasing
	1,900,000	American Commercial Lines (a)		49,495
		Operator of Inland Barges/Builder of Inland Barges
	2,000,000	Labor Ready (a)		46,220
		Temporary Manual Labor
	374,000	Imtech (Netherlands)		32,444
		Engineering & Technical Services
	600,000	G&K Services		23,706
		Uniform Rental
	655,000	TAL International Group		19,460
		Intermodal Freight Containers Leasing
	631,000	Intertek Testing (United Kingdom)		12,371
		Testing, Inspection, Certification Services
				660,630
		> Construction 1.9%
	1,900,000	Florida Rock		128,250
		Aggregates & Concrete
	650,000	Martin Marietta Materials		105,313
		Aggregates
	2,200,000	Simpson Manufacturing		74,228
		Wall Joint Maker
	300,000	Geberit (Switzerland)		51,187
		Plumbing Supplies
	175,000	Vulcan Materials		20,044
		Aggregates, Concrete & Asphalt
	700,000	Kingspan Group (Ireland)		19,575
		Building Insulation & Environmental Containers
				398,597

28

Number of Shares			Value (000)
		> Industrial Materials & Specialty Chemicals 1.7%
	590,000	Novozymes (Denmark)	$	68,394
		Industrial Enzymes
	28,000	Sika (Switzerland)		57,146
		Chemicals for Construction & Industrial Applications
	2,000,000	Spartech (b)		53,100
		Plastics Distribution & Compounding
	1,228,000	Drew Industries (a)(b)		40,696
		RV & Manufactured Home Components
	195,000	Sociedad Quimica y Minera de Chile (Chile)		33,548
		Producer of Specialty Fertilizers, Lithium, & Iodine
	400,000	Carbone Lorraine (France)		31,042
		Advanced Industrial Materials
	700,000	Albany International		28,308
		Paper Machine Clothing and Advanced Textiles
	400,000	Cytec Industries		25,508
		Aerospace Composites & Specialty Chemical
	441,384	Koninklijke TenCate (Netherlands)		16,895
		Advanced Textiles & Industrial Fabrics
	611,460	Wavin (Netherlands)		14,709
		Largest European Plastic Pipe Systems Company
	124,000	Kansai Paint (Japan)		1,083
		Paint Producer in Japan, India, China & Southeast Asia
				370,429
		> Industrial Distribution 1.7%
	2,375,000	Watsco (b)		129,200
		HVAC Distribution
	1,300,000	WW Grainger		120,965
		Industrial Distribution
	1,925,000	Airgas		92,207
		Industrial Gas Distributor
	1,000,000	Interline Brands (a)		26,080
		Industrial Distribution
				368,452
		> Electrical Components 1.3%
	2,600,000	Genlyte Group (a)(b)		204,204
		Commercial Lighting Fixtures
	700,000	Legrand (France)		25,191
		Electrical Components
	1,125,000	Ushio (Japan)		24,927
		Industrial Light Sources
	500,000	Zumtobel (Austria) (a)		18,651
		Lighting Systems
				272,973
		> Conglomerates 1.0%
	4,845,000	Hexagon (Sweden)		92,916
		Measurement Equipment & Polymers
	2,758,309	Aalberts Industries (Netherlands)		75,736
		Flow Control & Heat Treatment
	600,000	Ibiden (Japan)		38,634
		Electronic Parts & Ceramics
	56,492	Stork (Netherlands)		3,667
		Industrial Services & Food Processing Equipment
				210,953

Number of Shares			Value (000)
		> Outsourcing Services 0.8%
	2,200,000	Quanta Services (a)	$	67,474
		Electrical & Telecom Construction Services
	1,900,000	Administaff (b)		63,631
		Professional Employer Organization
	817,021	USG People (Netherlands)		38,383
		Temporary Staffing Services
	600,000	GP Strategies (a)		6,528
		Training Programs
				176,016
		> Steel 0.7%
	2,860,000	Gibraltar Industries (b)		63,349
		Steel Processing & Building Products
	135,000	Vallourec (France)		43,143
		Oil, Gas & Industrial Seamless Tubes
	1,500,000	Worthington Industries		32,475
		Steel Processing & Manufactured Metal Products
				138,967
		> Waste Management 0.4%
	2,550,000	Waste Connections (a)		77,112
		Solid Waste Management
				77,112
Industrial Goods & Services: Total				3,845,356
Consumer Goods & Services 18.1%
		> Retail 4.1%
	3,140,000	Abercrombie & Fitch		229,157
		Teen Apparel Retailer
	9,130,000	Chico's FAS (a)(b)		222,224
		Women's Specialty Retailer
	4,600,000	Urban Outfitters (a)		110,538
		Apparel & Home Specialty Retailer
	1,975,000	J Crew Group (a)		106,828
		Multi-channel Branded Retailer
	3,743,000	Christopher & Banks (b)		64,192
		Women's Apparel Retailer
	1,223,000	AnnTaylor Stores (a)		43,319
		Women's Apparel Retailer
	1,954,600	RONA (Canada) (a)		40,826
		Leading Canadian Do-it-yourself Retailer
	775,000	Genesco (a)		40,540
		Multi-concept Branded Footwear Retailer
	1,200,000	Gaiam (a)(b)		21,876
		Healthy Living Catalogs & E-commerce
				879,500
		> Other Consumer Services 2.5%
	2,000,000	ITT Educational Services (a)		234,760
		Post-secondary Degree Programs
	5,400,000	ServiceMaster		83,484
		Lawn Care, Pest Control, Commercial Disaster Responce
	1,120,000	NutriSystem (a)		78,221
		Weight Loss Programs
	1,275,000	Weight Watchers International		64,821
		Weight Loss Programs
	1,500,000	Universal Technical Institute (a)(b)		38,085
		Vocational Training

29

Columbia Acorn Fund

Statement of Investments (Unaudited), continued

Number of Shares			Value (000)
		> Other Consumer Services—continued
	110,000	Pierre & Vacances (France)	$	16,782
		Vacation Apartment Lets
	2,550,000	Princeton Review (a)(b)		12,189
		College Preparation Courses
	100,000	Lincoln Technical Institute (a)		1,486
		Vocational Training
				529,828
		> Apparel 2.5%
	7,330,000	Coach (a)		347,369
		Designer & Retailer of Branded Leather Accessories
	1,069,000	Oxford Industries (b)		47,399
		Branded & Private Label Apparel
	1,818,000	Carter's (a)		47,159
		Children's Branded Apparel
	3,000,000	Billabong International (Australia)		45,426
		Action Sports Apparel Brand Manager
	900,000	True Religion Apparel (a)		18,297
		Premium Denim
	600,000	Heelys (a)		15,516
		Wheeled Footwear
				521,166
		> Leisure Products 1.7%
	1,500,000	Harley-Davidson		89,415
		Motorcycles & Related Merchandise
	1,416,000	Speedway Motorsports		56,612
		Motorsport Racetrack Owner & Operator
	1,025,000	International Speedway		54,028
		Largest Motorsports Racetrack Owner & Operator
	900,000	Polaris Industries		48,744
		Leisure Vehicles & Related Products
	1,032,000	RC2 (a)		41,290
		Toys, Infant Products & Collectibles
	561,000	Thor Industries		25,323
		RV & Bus Manufacturer
	2,500,000	Fleetwood Enterprises (a)		22,625
		RV & Manufactured Home Maker
	390,000	Winnebago		11,513
		Premier Motorhome Maker
				349,550
		> Nondurables 1.6%
	2,860,000	Scotts Miracle-Gro		122,808
		Consumer Lawn & Garden Products
	2,060,000	Jarden (a)		88,601
		Branded Household Products
	1,010,000	Chattem (a)(b)		64,014
		Personal Care Products
	1,800,000	Helen of Troy (a)(b)		48,600
		Hair Dryers & Curling Irons
	1,100,000	Natura Cosmeticos (Brazil)		15,967
		Direct Retailer of Cosmetics
				339,990
		> Furniture & Textiles 1.4%
	3,800,000	Herman Miller (b)		120,080
		Office Furniture
	2,236,000	HNI		91,676
		Office Furniture & Fireplaces

Number of Shares			Value (000)
	1,818,000	Knoll	$	40,723
		Office Furniture
	3,144,000	Nobia (Sweden)		39,129
		Kitchen Cabinet Manufacturing & Distribution
				291,608
		> Travel 1.3%
	2,390,000	Vail Resorts (a)(b)		145,479
		Ski Resort Operator & Developer
	4,000,000	Expedia (a)		117,160
		Online Travel Services Company
	425,000	Choice Hotels		16,796
		Franchisor of Budget Hotel Brands
	135,000	Ambassadors Group		4,797
		Educational Student Travel Services
				284,232
		> Casinos & Gaming 1.2%
	1,700,000	Penn National Gaming (a)		102,153
		Regional Casino Operator
	3,200,000	Pinnacle Entertainment (a)(b)		90,080
		Regional Casino Operator
	400,000	Station Casinos		34,720
		Las Vegas Locals Casinos
	690,000	Intralot (Greece)		22,228
		Lottery & Gaming Systems & Services
	226,000	Lakes Entertainment (a)		2,669
		Native American Casinos Development
				251,850
		> Restaurants 0.7%
	2,145,000	Sonic (a)		47,447
		Quick Service Restaurant
	1,000,000	Red Robin Gourmet Burgers (a)(b)		40,370
		Casual Dining Restaurant
	1,150,000	Cheesecake Factory (a)		28,198
		Casual Dining Restaurants
	1,600,000	AFC Enterprises (a)(b)		27,664
		Popeyes Restaurants
				143,679
		> Consumer Goods Distribution 0.5%
	2,890,000	Pool (b)		112,797
		Distributor of Swimming Pool Supplies & Equipment
				112,797
		> Food & Beverage 0.4%
	1,650,000	Hansen Natural (a)		70,917
		Alternative Beverages
	1,000,000	IAWS Group (Ireland)		20,947
		Baked Goods
	26,000	C&C Group (Ireland)		349
		Beverage Company
				92,213
		> Other Durable Goods 0.1%
	5,410,390	Ducati Motor (Italy) (a)		13,169
		Motorcycles & Related Merchandise
	900,000	Champion Enterprises (a)		8,847
		Manufactured Homes
	172,000	Cavco Industries (a)		6,453
		Higher End Manufactured Homes
				28,469

30

Number of Shares			Value (000)
		> Cruise Lines 0.1%
	400,000	Carnival	$	19,508
		Largest Cruise Line
				19,508
Consumer Goods & Services: Total				3,844,390
Finance 12.3%
		> Insurance 3.9%
	3,600,000	HCC Insurance Holdings		120,276
		Specialty Insurance
	5,000,000	Conseco (a)		104,450
		Life, Long Term Care, & Medical Supplement Insurance
	2,390,000	Philadelphia Consolidated Holding (a)		99,902
		Specialty Insurance
	149,000	Markel (a)		72,199
		Specialty Insurance
	1,200,000	Assurant		70,704
		Specialty Insurance
	1,748,000	Leucadia National		61,617
		Insurance Holding Company
	995,000	Protective Life		47,571
		Life Insurance
	1,000,000	Endurance Specialty Holdings		40,040
		Commercial Lines Insurance/Reinsurance
	740,000	Stancorp Financial Group		38,835
		Group Life & Disability Insurance
	1,550,000	United America Indemnity (a)(b)		38,548
		Specialty Insurance
	1,420,000	Selective Insurance Group		38,170
		Commercial & Personal Lines Insurance
	750,000	Delphi Financial Group		31,365
		Group Employee Benefit Products & Services
	1,000,000	Aspen Insurance		28,070
		Commercial Lines Insurance/Reinsurance
	600,000	National Financial Partners		27,786
		Distributor of Life Insurance, Group Benefits & Investment Advisory Services
	280,000	April Group (France)		14,750
		Insurance Policy Construction
				834,283
		> Banks 3.0%
	2,852,000	BOK Financial		152,354
		Tulsa Based S.W. Bank
	3,450,000	Associated Banc-Corp		112,815
		Midwest Bank
	3,156,000	TCF Financial		87,737
		Great Lakes Bank
	4,080,000	Glacier Bancorp (b)		83,028
		Mountain States Bank
	1,222,000	Chittenden		42,709
		New England Bank
	1,320,000	West Coast Bancorp (b)		40,115
		Portland Small Business Bank
	700,000	MB Financial		24,318
		Chicago Bank
	1,249,000	West Bancorporation (b)		19,946
		Des Moines Commercial Bank

Number of Shares			Value (000)
	1,000,000	Depfa Bank (Ireland)	$	17,706
		Investment Banker to Public Authorities
	636,000	Great Southern Bancorp		17,204
		Missouri Real Estate Lender
	386,000	First Financial Bankshares		14,980
		West Texas Bank
	400,000	First Mutual Bancshares (b)		8,892
		Seattle Community Bank
	250,000	First Busey		4,997
		Illinois Bank
	150,000	Greene County Bancshares		4,689
		Tennessee Bank
	200,000	TriCo Bancshares		4,472
		California Central Valley Community Bank
				635,962
		> Brokerage & Money Management 2.4%
	5,500,000	Eaton Vance		242,990
		Specialty Mutual Funds
	5,948,000	SEI Investments		172,730
		Mutual Fund Administration & Investment Management
	1,303,000	Nuveen Investments		80,981
		Money Management
	450,000	Investment Technology Group (a)		19,499
		Electronic Trading
				516,200
		> Finance Companies 1.5%
	6,500,000	AmeriCredit (a)(b)		172,575
		Auto Lending
	1,500,000	World Acceptance (a)(b)		64,095
		Personal Loans
	1,219,000	McGrath Rentcorp		41,068
		Temporary Space & IT Rentals
	900,000	Marlin Business Services (a)(b)		19,179
		Small Equipment Leasing
	1,203,000	Electro Rent		17,492
		Test & Measurement Rentals
	200,000	CAI International (a)		2,636
		International Container Leasing & Management
				317,045
		> Savings & Loans 1.5%
	9,085,000	People's United		161,077
		Connecticut Savings & Loan
	1,700,000	Housing Development Finance (India)		84,475
		Indian Mortgage Lender
	1,285,000	Washington Federal		31,238
		Traditional Thrift
	978,000	Anchor Bancorp Wisconsin		25,614
		Wisconsin Thrift
	360,000	Provident New York Bancorp		4,864
		New York State Thrift
				307,268
Finance: Total				2,610,758

31

Columbia Acorn Fund

Statement of Investments (Unaudited), continued

Number of Shares			Value (000)
Energy & Minerals 8.7%
		> Oil & Gas Producers 4.0%
	2,500,000	XTO Energy	$	150,250
		Oil & Gas Producer
	2,700,000	Ultra Petroleum (a)		149,148
		Oil & Gas Producer
	2,400,000	Equitable Resources		118,944
		Natural Gas Producer & Utility
	4,900,000	Talisman Energy (Canada)		94,757
		Oil & Gas Producer
	9,315,000	Tullow Oil (United Kingdom)		90,769
		Oil & Gas Producer
	2,000,000	Southwestern Energy (a)		89,000
		Oil & Gas Producer
	1,500,000	Range Resources		56,115
		Oil & Gas Producer
	1,100,000	Carrizo Oil & Gas (a)		45,617
		Explores for Natural Gas & Crude Oil
	700,000	Denbury Resources (a)		26,250
		Oil Producer Using Co2 Injection
	500,000	St. Mary Land & Exploration		18,310
		Oil & Gas Producer
	2,750,000	Vaalco Energy (a)		13,283
		Oil & Gas Producer
	470,000	McMoran Exploration (a)		6,580
		Natural Gas Producer & Developer
				859,023
		> Oil Services 3.8%
	3,584,037	Fugro (Netherlands) (b)		227,455
		Oilfield Services
	2,820,000	FMC Technologies (a)		223,400
		Oil & Gas Well Head Manufacturer
	1,200,000	Atwood Oceanics (a)		82,344
		Offshore Drilling Contractor
	1,761,000	Rowan		72,166
		Offshore Drilling Contractor
	1,988,000	Tetra Technologies (a)		56,062
		U.S.-based Services Company with Life of Field Approach
	1,044,000	Tesco (a)		32,938
		Developing New Well Drilling Technologies
	750,000	CARBO Ceramics		32,858
		Natural Gas Well Stimulants
	1,001,000	ShawCor (Canada)		30,737
		Oil & Gas Pipeline Products
	552,000	Dresser-Rand Group (a)		21,804
		Largest Manufacturer of Compressors
	1,580,000	Enerflex Systems (Canada)		15,633
		Natural Gas Compresser Rental & Fabrication
	250,000	SBM Offshore (Netherlands)		9,530
		Builds & Leases Offshore Vessels to Process & Store Crude Oil
	170,000	Key Energy Services (a)		3,150
		Well Workover Services
				808,077
		> Mining 0.6%
	5,895,000	Uranium One (South Africa) (a)		75,095
		Uranium Mines in South Africa, Kazakhstan, Australia & the U.S.

Number of Shares			Value (000)
	2,900,000	Jubilee Mines (Australia)	$	39,163
		Nickel Mining in Australia
	1,000,000	Ivanhoe Mines (Canada) (a)		14,175
		Copper Mine Project in Mongolia
				128,433
		> Agricultural Commodities 0.2%
	550,000	Aracruz Celulose (Brazil)		36,432
		Brazilian Hardwood Pulp Producer
				36,432
		> Oil Refining, Marketing & Distribution 0.1%
	435,000	Oneok		21,928
		Natural Gas Distribution, Pipeline Processing & Trading
				21,928
Energy & Minerals: Total				1,853,893
Health Care 7.9%
		> Health Care Services 1.9%
	1,000,000	Rhoen-Klinikum (Germany)		60,256
		Health Care Services
	1,085,000	Charles River Laboratories (a)		56,008
		Pharmaceutical Research
	1,125,000	LCA-Vision (b)		53,167
		Lasik Surgery Centers
	1,300,000	Lincare Holdings (a)		51,805
		Home Health Care Services
	2,250,000	PSS World Medical (a)		40,995
		Medical Supplies
	1,080,000	OPG Groep (Netherlands)		39,327
		Health Care Supplies & Pharmacies
	900,000	Omnicare		32,454
		Pharmacy Services for Nursing Homes
	500,000	Coventry Health Care (a)		28,825
		HMO
	3,000,000	Eresearch Technology (a)(b)		28,530
		Clinical Research Services
	400,000	Healthcare Services Group		11,800
		Outsourced Services to Long-term Care Industry
				403,167
		> Medical Supplies 1.9%
	1,910,000	Cytyc (a)		82,340
		Consumables Related to Women's Health
	1,250,000	ICU Medical (a)(b)		53,675
		Intravenous Therapy Products
	929,000	Henry Schein (a)		49,637
		Largest Distributor of Healthcare Products
	1,200,000	Owens & Minor		41,928
		Distribution of Medical Supplies
	1,025,000	Polymedica		41,871
		Diabetes Supply Distributor
	700,000	Cooper		37,324
		Contact Lens Manufacturer
	905,000	Arrow International		34,644
		Disposable Catheters
	486,000	Techne (a)		27,804
		Cytokines, Antibodies & Other Reagents for Life Science

32

Number of Shares			Value (000)
		> Medical Supplies—continued
	790,000	Meridian Biosciences	$	17,111
		Niche Diagnostics/Life Science Company
	900,000	QIAGEN (a)		16,011
		Life Science Company; DNA/RNA Purification
				402,345
		> Biotechnology & Drug Delivery 1.7%
	3,940,000	BioMarin (a)		70,684
		Biotech Focused on Orphan Diseases
	2,550,000	PDL BioPharma (a)		59,415
		Proprietary Monoclonal Antibodies
	3,720,000	Seattle Genetics (a)(b)		36,493
		Antibody-based Therapies for Cancer
	865,000	Amylin (a)		35,603
		Biotech Company Focused on Diabetes & Obesity
	2,000,000	Medarex (a)		28,580
		Humanized Antibodies
	2,160,000	Array Biopharma (a)		25,207
		Drugs for Cancer & Inflammatory Diseases
	650,000	Myriad Genetics (a)		24,173
		Drugs/Diagnostics Hybrid
	1,650,000	Nektar Therapeutics (a)		15,659
		Drug Delivery Technologies
	1,320,000	Arena Pharmaceuticals (a)		14,507
		Novel Drug Targeting Technology
	3,100,000	Lexicon Genetics (a)		9,951
		Drug Discovery
	2,520,000	Decode Genetics (a)		9,412
		Drugs for Heart Attack, Asthma & Vascular Disease
	1,229,000	Neurogen (a)		8,161
		Development-stage Biotech Focused on Neurology
	1,750,000	Genitope (a)		6,755
		Cancer Vaccine
	1,100,000	La Jolla Pharmaceutical (a)		4,928
		Lupus Treatment
	825,000	Pharmacopeia (a)		4,579
		Biotech Company with Broad Early-stage Pipeline
	1,025,000	Nuvelo (a)		2,788
		Development-stage Biotech Focused on Cardiovascular/Cancer
	1,875,000	Locus Discovery, Series D, Pfd. (a)(c)		544
	966,441	Locus Discovery, Series B, Pfd. (a)(c)		280
		High Throughput Rational Drug Design
	1,249,999	Perlegen Sciences (a)(c)		400
		Large Scale Gene Sequencing
	359,944	MicroDose Technologies (a)(c)		360
		Drug Inhaler Development
				358,479
		> Medical Equipment & Devices 1.3%
	1,000,000	Edwards Lifesciences (a)		49,340
		Heart Valves
	870,000	Vital Signs (b)		48,328
		Anesthesia, Respiratory & Sleep Products
	943,000	Orthofix International (a)(b)		42,407
		Bone Fixation & Stimulation Devices
	315,000	Synthes (Switzerland)		37,806
		Products for Orthopedic Surgery

Number of Shares			Value (000)
	550,000	Dade Behring	$	29,216
		Clinical Diagnostics Supplier
	550,000	Haemonetics (a)		28,935
		Blood & Plasma Collection Equipment
	552,000	Advanced Medical Optics (a)		19,254
		Medical Devices for Eye Care
	140,000	Essilor International (France)		16,675
		Eyeglass Lenses
				271,961
		> Pharmaceuticals 1.1%
	900,000	Cephalon (a)		72,351
		Specialty Pharmaceuticals for Pain, Central Nervous System & Oncology
	1,295,000	Endo Pharmaceuticals (a)		44,328
		Specialty Pharmaceuticals for Pain Management
	1,000,000	Medicis Pharmaceutical		30,540
		Specialty Pharmaceuticals for Dermatology
	1,010,000	MGI Pharma (a)		22,594
		Specialty Pharmaceuticals for Oncology & Acute Care
	3,000,000	QLT (a)		22,200
		Specialty Pharmaceuticals for Ophthalmology & Dermatology
	3,100,000	United Drug (Ireland)		16,928
		Irish Pharmaceutical Wholesaler & Outsourcer
	1,200,000	Collagenex Pharmaceuticals (a)(b)		14,880
		Specialty Pharmaceuticals for Dermatology
	1,700,000	Barrier Therapeutics (a)(b)		11,050
		Specialty Pharmaceuticals for Dermatology
				234,871
Health Care: Total				1,670,823
Other Industries 4.9%
		> Real Estate 3.8%
	5,850,000	Highland Hospitality (b)		112,320
		Hotel Owner
	2,000,000	Gaylord Entertainment (a)		107,280
		Convention Hotels
	1,398,000	Forest City Enterprises, Class B (b)		86,690
		Commercial & Residential Property Developer
	650,000	SL Green Realty		80,528
		Manhattan Office Buildings
	1,320,000	General Growth Properties		69,894
		Regional Shopping Malls
	3,500,000	DiamondRock Hospitality		66,780
		Hotel Owner
	635,000	Macerich Company		52,337
		Regional Shopping Malls
	575,000	Federal Realty Investment Trust		44,425
		Shopping Centers
	1,720,000	Kite Realty Group (b)		32,714
		Community Shopping Centers
	850,000	Digital Realty Trust		32,028
		Technology-focused Office Buildings
	1,375,000	Crescent Real Estate Equities		30,855
		Class 'A' Office Buildings
	628,000	Parkway Properties		30,163
		Office Buildings

33

Columbia Acorn Fund

Statement of Investments (Unaudited), continued

Number of Shares or Principal Amount (000)			Value (000)
		> Real Estate—continued
	1,020,000	Brandywine Realty	$	29,152
		Office Buildings
	900,000	American Campus Communities		25,461
		Student Housing
	8,200	Kenedix (Japan)		15,252
		Real Estate Investment Management
	37,407	Security Capital European Realty (Luxembourg) (a)(c)(d)		—
		Self Storage Properties
				815,879
		> Transportation 0.8%
	1,556,000	JB Hunt Transport Services		45,622
		Truck & Intermodal Carrier
	826,200	Grupo Aeroportuario del Surest (Mexico)		43,533
		Cancun & Cozumel Airport Operator
	14,120,000	China Shipping Development (China)		32,569
		China's Dominant Shipper for Oil & Coal
	1,914,000	Heartland Express		31,198
		Regional Trucker
	6,790,000	Jiangsu Expressway (China)		6,906
		Chinese Toll Road Operator
				159,828
		> Regulated Utilities 0.3%
	1,650,000	Northeast Utilities		46,794
		Regulated Electric Utility
	340,000	Red Electrica de Espana (Spain)		15,932
		Spanish Power Grid
				62,726
Other Industries: Total				1,038,433
Total Equities: 93.6% (Cost: $11,345,002)				19,873,015
Short-Term Obligations 6.1%
$	50,000	Ebbetts Funding (e) 5.28% Due 7/11/07		49,927
	50,000	St. Germain Holdings (e) 5.28% Due 7/27/07		49,809
	50,000	Four Winds Funding (e) 5.27% Due 7/30/07		49,788
	50,000	Four Winds Funding (e) 5.27% Due 7/31/07		49,780
	50,000	Manhattan Asset Funding (e) 5.28% Due 8/01/07		49,773
	50,000	Liberty Street Funding (e) 5.28% Due 8/15/07		49,670
	48,000	Morrigan TRR (e) 5.28% Due 7/17/07		47,888
	45,000	Pasa Funding (e) 5.27% Due 7/19/07		44,881
	45,000	Ebury Finance (e) 5.28% Due 7/25/07		44,842
	45,000	White Point Funding (e) 5.29% Due 8/13/07		44,716

Principal Amount (000)			Value (000)
$	44,000	Hannover Funding (e) 5.28% Due 7/06/07	$	43,968
	44,000	World Omni Vehicles (e) 5.26% Due 7/09/07		43,949
	44,000	World Omni Vehicles (e) 5.26% Due 7/10/07		43,942
	44,000	Axon Financial (e) 5.28% Due 8/09/07		43,748
	44,000	Axon Financial (e) 5.28% Due 8/10/07		43,742
	43,000	Nightingale (e) 5.28% Due 8/08/07		42,760
	40,000	Ebbetts Funding (e) 5.27% Due 7/16/07		39,912
	40,000	Mica Funding LLC (e) 5.28% Due 8/06/07		39,789
	38,000	Mica Funding LLC (e) 5.26% Due 7/12/07		37,939
	38,000	Keel Capital (e) 5.27% Due 7/13/07		37,933
	38,000	Ebury Finance (e) 5.27% Due 7/24/07		37,872
	38,000	White Point Funding (e) 5.28% Due 8/14/07		37,755
	37,000	Mainsail II Ltd. (e) 5.27% Due 7/20/07		36,897
	37,000	Morrigan TRR (e) 5.28% Due 7/23/07		36,881
	36,000	La Fayette Asset Securitization LLC (e) 5.28% Due 7/03/07		35,989
	36,000	Anglesea Funding (e) 5.26% Due 7/05/07		35,979
	35,000	Anglesea Funding (e) 5.26% Due 7/02/07		34,995
	30,000	East Fleet Financial (e) 5.28% Due 7/26/07		29,890
	30,000	Pasa Funding (e) 5.27% Due 8/02/07		29,859
	28,000	Manhattan Asset Funding (e) 5.27% Due 8/03/07		27,865
	25,000	Morrigan TRR (e) 5.28% Due 7/18/07		24,938
	23,000	Mica Funding LLC (e) 5.28% Due 8/07/07		22,875
	7,804	Repurchase Agreement with Fixed Income Clearing Corp., dated 6/29/07, due 7/02/07 at 5.050%, collateralized by a U.S. Government Agency Obligation, maturing 7/18/11, market value $7,960 (repurchase proceeds $7,807)		7,804
		(Amortized Cost: $1,298,355)		1,298,355
Total Investments: 99.7% (Cost: $12,643,357)(f)(g)				21,171,370
Cash and Other Assets Less Liabilities: 0.3%				59,908
Total Net Assets: 100%			$	21,231,278

34

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

(a)  Non-income producing security.

(b)  An affiliate may include any company in which the Fund owns five percent or more of its outstanding voting shares. Transactions in affiliated companies during the six months ended June 30, 2007, are as follows:

Affiliates	Balance of Shares Held 12/31/06		Purchases/ Additions		Sales/ Reductions		Balance of Shares Held 6/30/07		Value		Dividend
Actuate		6,000,000		-		-		6,000,000	$	40,740	$	-
Administaff		1,670,000		230,000		-		1,900,000		63,631		407
AFC Enterprises		1,600,000		-		-		1,600,000		27,664		-
Agile Software		3,500,000		-		-		3,500,000		28,210		-
AmeriCredit		6,500,000		-		-		6,500,000		172,575		-
Anchor Bancorp Wisconsin*		1,178,000		-		200,000		978,000		25,614		401
AnswerThink		4,600,000		-		-		4,600,000		16,652		-
Bally Technologies		3,500,000		-		350,000		3,150,000		83,223		-
Barrier Therapeutics		1,321,000		379,000		-		1,700,000		11,050		-
Chattem		1,010,000		-		-		1,010,000		64,014		-
Chico's FAS		7,080,000		2,050,000		-		9,130,000		222,224		-
Christopher & Banks		3,743,000		-		-		3,743,000		64,192		449
Clarcor		3,500,000		-		-		3,500,000		131,005		508
Collagenex Pharmaceuticals		830,000		370,000		-		1,200,000		14,880		-
Concur Technologies		2,131,000		-		-		2,131,000		48,693		-
Cytokinetics*		486,000		-		486,000		-		-		-
Dobson Communications		8,000,000		-		-		8,000,000		88,880		-
Donaldson		3,600,000		400,000		-		4,000,000		142,200		666
Drew Industries		1,228,000		-		-		1,228,000		40,696		-
Enerflex Systems*		2,280,000		-		700,000		1,580,000		15,633		640
Eresearch Technology		2,300,000		700,000		-		3,000,000		28,530		-
ESCO Technologies		2,200,000		-		-		2,200,000		79,772		-
Excel Technology		625,000		110,000		-		735,000		20,536		-
FARO Technologies		-		860,000		-		860,000		27,400		-
First Mutual Bancshares		400,000		-		-		400,000		8,892		72
Fleetwood Enterprises*		4,690,000		-		2,190,000		2,500,000		22,625		-
Forest City Enterprises, Class B		1,398,000		-		-		1,398,000		86,690		196
Forward Air		1,900,000		-		-		1,900,000		64,771		266
Fugro		2,928,301		655,736		-		3,584,037		227,455		3,860
Gaiam		1,200,000		-		-		1,200,000		21,876		-
Genlyte Group		1,963,000		637,000		-		2,600,000		204,204		-
Gibraltar Industries		2,860,000		-		-		2,860,000		63,349		429
Glacier Bancorp		4,080,000		-		-		4,080,000		83,028		979
Helen of Troy		1,800,000		-		-		1,800,000		48,600		-
Herman Miller		2,068,000		1,732,000		-		3,800,000		120,080		482
Highland Hospitality		5,850,000		-		-		5,850,000		112,320		1,346
HNI*		2,550,000		-		314,000		2,236,000		91,676		978
ICU Medical		1,083,000		167,000		-		1,250,000		53,675		-
iGate		5,000,000		-		-		5,000,000		40,100		-
II-VI		2,025,000		195,000		-		2,220,000		60,317		-
Indus International (merged into Vista Equity)*		5,600,000		-		5,600,000		-		-		-
ITT Educational Services*		2,250,000		-		250,000		2,000,000		234,760		-
IXYS		1,905,000		-		-		1,905,000		15,907		-
JDA Software*		1,490,000		-		1,490,000		-		-		-
Kite Realty Group		1,720,000		-		-		1,720,000		32,714		671
Kronos (merged into Helman & Friedman)*		2,750,000		-		2,750,000		-		-		-
LCA-Vision		1,125,000		-		-		1,125,000		53,167		405
Littelfuse		1,135,000		135,000		-		1,270,000		42,888		-
Marlin Business Services		685,000		215,000		-		900,000		19,179		-
Mine Safety Appliances		1,900,000		-		-		1,900,000		83,144		760
Orthofix International		942,500		500		-		943,000		42,407		-
Oxford Industries		919,000		150,000		-		1,069,000		47,399		358
Pinnacle Entertainment		3,200,000		-		-		3,200,000		90,080		-
Pool		2,500,000		390,000		-		2,890,000		112,797		636
Princeton Review		2,550,000		-		-		2,550,000		12,189		-
ProQuest		2,000,000		-		-		2,000,000		19,080		-
Radiant Systems		2,500,000		-		-		2,500,000		33,100		-
Red Robin Gourmet Burgers		1,000,000		-		-		1,000,000		40,370		-
Saga Communications		1,400,000		-		-		1,400,000		13,720		-
Salem Communications		1,541,000		-		-		1,541,000		17,090		-
Seachange International*		1,875,000		-		1,875,000		-		-		-
Seattle Genetics		2,300,000		1,420,000		-		3,720,000		36,493		-
Shuffle Master		2,430,000		-		-		2,430,000		40,338		-
Skillsoft		9,500,000		-		-		9,500,000		88,255		-
Spanish Broadcasting System		2,400,000		-		-		2,400,000		10,320		-
Spartech		2,700,000		-		700,000		2,000,000		53,100		635
Supertex		690,000		260,000		130,000		820,000		25,699		-
Tumbleweed Communications		3,500,000		-		-		3,500,000		8,925		-

35

Columbia Acorn Fund

Statement of Investments (Unaudited), continued

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

Affiliates	Balance of Shares Held 12/31/06		Purchases/ Additions		Sales/ Reductions		Balance of Shares Held 6/30/07		Value		Dividend
United America Indemnity		1,550,000		-		-		1,550,000		38,548		-
Universal Technical Institute		1,500,000		-		-		1,500,000		38,085		-
Vaalco Energy*		3,200,000		-		450,000		2,750,000		13,283		-
Vail Resorts		2,390,000		-		-		2,390,000		145,479		-
Vital Signs		870,000		-		-		870,000		48,328		165
Watsco		2,375,000		-		-		2,375,000		129,200		1,378
West Bancorporation		949,000		300,000		-		1,249,000		19,946		330
West Coast Bancorp		1,320,000		-		-		1,320,000		40,115		317
Witness Systems*		2,500,000		-		2,500,000		-		-		-
World Acceptance		1,500,000		-		-		1,500,000		64,095		-
TOTAL OF AFFILIATED TRANSACTIONS		193,338,801		11,356,236		19,985,000		184,710,037	$	4,477,872	$	17,334

*  At June 30, 2007, the Fund owned less than five percent of the company's outstanding voting shares.

  The aggregate cost and value of these companies at June 30, 2007, was $2,646,859 and $4,477,872 respectively. Investments in affiliate companies represent 21.09% of total net assets at June 30, 2007.

(c)  Denotes a restricted security, which is subject to restrictions on resale under federal securities laws. These securities, are valued in good faith by the Board of Trustees. At June 30, 2007, these securities had an aggregate value of $1,584 which represented 0.01% of total net assets.

  Additional information on these securities is as follows:

Security	Acquisition Dates	Shares		Cost		Value
Perlegen Sciences	3/30/01		1,249,999	$	4,500	$	400
Locus Discovery, Series D Pfd.	9/5/01		1,875,000		7,500		544
MicroDose Technologies	11/24/00		359,944		2,005		360
Locus Discovery, Series B Pfd.	2/8/07		966,441		280		280
Security Capital European Realty	8/20/98 - 11/12/99		37,407		205		-
				$	14,490	$	1,584

(d)  Security has no value.

(e)  Security exempt from registration under Section 4(2) of the Securities Act of 1933. These securities may only be resold in exempt transactions to qualified buyers. Private resales of these securities to qualified instutional buyers are also exempt from registration pursuant to Rule 144A under the Securities Act of 1933. At June 30, 2007, these securities had an aggregate value of $1,290,551, which represented 6.1% of net assets.

(f)  At June 30, 2007, for federal income tax purposes cost of investments was $12,643,357 and net unrealized appreciation was $8,528,013 consisting of gross unrealized appreciation of $8,815,065 and gross unrealized depreciation of $287,052.

(g)  On June 30, 2007, the market value of foreign securities represents 11.5% of total net assets. The Fund's foreign portfolio was diversified as follows:

	Value		Percent
Netherlands	$	458,146		2.16	%
France		223,347		1.05
Canada		217,427		1.02
Japan		150,917		0.71
Switzerland		146,139		0.69
Sweden		132,045		0.62
United Kingdom		128,743		0.61
Germany		102,892		0.48
Hong Kong		91,966		0.43
Australia		84,589		0.40
India		84,475		0.40
Ireland		75,505		0.36
South Africa		75,095		0.35
China		71,465		0.34
	Value		Percent
Denmark	$	68,394		0.32	%
Brazil		52,399		0.25
Israel		49,539		0.23
Taiwan		48,918		0.23
Mexico		43,533		0.21
Chile		33,548		0.16
Singapore		31,933		0.15
Greece		22,228		0.10
Austria		18,651		0.09
Spain		15,932		0.08
Italy		13,169		0.06
Luxembourg		-		-
Total Foreign Portfolio	$	2,440,995		11.50	%

36

Columbia Acorn International

Major Portfolio Changes in the Second Quarter (Unaudited)

	Number of Shares
	03/31/07		06/30/07
Additions
Europe
> Netherlands
Aalberts Industries		480,000		1,947,042
Boskalis Westminster		163,000		489,000
Fugro		1,271,700		1,406,155
Koninklijke TenCate		973,000		1,096,000
OPG Groep		191,000		764,000
SBM Offshore		0		450,000
Smit Internationale		520,000		680,000
Stork		0		825,000
Wavin		840,000		1,182,536
> France
Rubis		298,818		332,020
Trigano		500,000		571,000
> Germany
Deutsche Beteiligungs		283,000		354,500
Deutsche Boerse		120,000		200,000
MPC Muechmeyer Petersen Capital		0		300,000
> Switzerland
Kuehne & Nagel		550,000		600,000
Nobel Biocare Holding		95,000		140,000
Synthes		330,000		360,000
> United Kingdom
Informa Group		0		1,400,000
Intertek Testing		0		517,000
Northgate		1,450,000		1,875,000
Rotork		0		448,000
Smith & Nephew		2,205,000		2,670,000
Taylor Nelson Sofres		4,620,000		5,922,000
> Ireland
Kingspan Group		1,035,000		1,050,000
United Drug		8,050,000		8,100,000
> Sweden
Hexagon		1,553,500		3,960,000
Nobia		755,000		2,265,000
SWECO		610,000		3,135,000
> Spain
Prisa		800,000		1,050,000
Sogecable		400,000		520,000
> Greece
Intralot		1,300,000		1,630,000

	Number of Shares
	03/31/07		06/30/07
Asia
> Japan
Aeon Delight		0		95,000
As One		396,000		585,000
FCC		900,000		1,150,000
Kansai Paint		3,700,000		6,000,000
Kansai Urban Banking		0		4,100,000
Nakanishi		92,000		145,000
Topcon		0		650,000
Unicharm PetCare		0		105,000
Union Tool		403,600		500,000
Yusen Air & Sea Service		1,273,900		1,300,000
> China
China Green		22,049,000		25,051,000
Fu Ji Food & Catering Services		4,782,000		6,256,000
Hopewell Highway Infrastructure		0		20,000,000
Jiangsu Expressway		0		17,918,000
Travelsky Technology		6,758,000		20,910,000
Xinyu Hengdeli		0		6,008,000
> Hong Kong
EganaGoldpfeil		26,600,000		29,344,000
Hong Kong Exchanges and Clearing		5,026,000		5,500,000
> South Korea
Sung Kwang Bend		714,000		915,000
> India
United Phosphorus		0		192,000
Other Countries
> United States
BioMarin		0		524,000
Dresser-Rand Group		0		500,000
FMC Technologies		189,000		379,000
Tesco		119,239		273,000
> New Zealand
Sky City Entertainment		5,661,208		5,773,789
Latin America
> Brazil
Localiza Rent A Car		500,000		1,500,000
> Mexico
Grupo Aeroportuario del Surest		411,000		500,000

37

Columbia Acorn International

Major Portfolio Changes in the Second Quarter (Unaudited) continued

	Number of Shares
	03/31/07		06/30/07
Sales
Europe
> Netherlands
USG People		1,103,000		929,361
> France
Neopost		200,000		160,000
> Germany
Gagfah		150,000		0
Hugo Boss Designs		525,000		425,000
> United Kingdom
Debt Free Direct		1,300,000		1,000,000
Keller Group		1,000,000		650,000
Northern Rock		2,100,000		0
Paragon Group		3,500,000		371,000
Workspace Group		2,450,000		1,280,000
> Ireland
Anglo Irish Bank		1,300,000		0
Bank of Ireland		2,000,000		845,000
C&C Group		1,260,000		255,000
Grafton Group		1,850,000		1,040,000
Ryanair		500,000		0
> Italy
Banca Italease		590,000		0
Ducati Motor		13,400,000		12,531,048
> Spain
Red Electrica de Espana		567,000		400,000

	Number of Shares
	03/31/07		06/30/07
Asia
> Japan
Chiba Bank		2,000,000		1,500,000
Daito Trust Construction		546,000		375,000
Hiroshima Bank		2,248,000		0
Hogy Medical		321,300		53,000
> Hong Kong
Melco-PBL Entertainment Macau		200,000		0
Techtronic Industries		14,000,000		0
> South Korea
Woongjin Thinkbig		183,500		0
Other Countries
> Canada
Major Drilling Group		530,000		0
Northern Orion Resources		839,000		0
Railpower Technologies		1,778,000		0
UrAsia Energy		6,775,000		0
> South Africa
Edgars Consolidated Stores		4,530,000		0
Latin America
> Brazil
Brascan Residential Properties		492,000		0
> Mexico
Grupo Aeroportuario Centro Norte		200,000		0
Grupo Aeroportuario del Pacifica		100,000		0

38

Columbia Acorn International

Statement of Investments (Unaudited), June 30, 2007

Number of Shares			Value (000)
				Equities: 91.9%
Europe 51.6%
		> Netherlands 9.3%
	1,406,155	Fugro	$	89,239
		Oilfield Services
	825,000	Stork		53,550
		Industrial Services & Food Processing Equipment
	1,947,042	Aalberts Industries		53,461
		Flow Control & Heat Treatment
	680,000	Smit Internationale		53,209
		Harbor & Offshore Towage & Marine Services
	929,361	USG People		43,660
		Temporary Staffing Services
	1,096,000	Koninklijke TenCate		41,953
		Advanced Textiles & Industrial Fabrics
	479,000	Imtech		41,552
		Engineering & Technical Services
	1,385,000	Unit 4 Agresso (a)		37,517
		Business & Security Software
	1,182,536	Wavin		28,447
		Largest European Plastic Pipe Systems Company
	764,000	OPG Groep		27,821
		Health Care Supplies & Pharmacies
	489,000	Boskalis Westminster		19,440
		Dredging & Maritime Contractor
	450,000	SBM Offshore		17,153
		Builds & Leases Offshore Vessels to Process & Store Crude Oil
				507,002
		> France 8.4%
	3,000,000	SES Global		64,665
		Satellite Broadcasting Services
	600,000	Carbone Lorraine		46,562
		Advanced Industrial Materials
	390,000	Iliad		39,404
		Alternative Internet & Telecoms Provider
	375,000	Norbert Dentressangle		36,304
		Transport
	571,000	Trigano		33,816
		Leisure Vehicles & Camping Equipment
	206,000	Pierre & Vacances		31,429
		Vacation Apartment Lets
	332,020	Rubis		29,711
		Tank Storage & LPG Supplier
	190,000	Bacou Dalloz		28,883
		Safety Equipment
	700,000	Legrand		25,191
		Electrical Components
	240,000	Imerys		24,341
		Industrial Minerals Producer
	160,000	Neopost		23,399
		Postage Meter Machines
	100,000	Ciments Francais		22,933
		Leading French & Emerging Markets Cement Producer
	240,000	Eurofins Scientific (b)		20,377
		Food Screening & Testing
	350,000	April Group		18,437
		Insurance Policy Construction

Number of Shares			Value (000)
	360,000	Meetic (b)	$	15,291
		Dating Services
				460,743
		> Germany 6.7%
	900,000	Rhoen-Klinikum		54,230
		Health Care Services
	775,000	CTS Eventim		38,171
		Event Ticket Sales
	400,000	Wincor Nixdorf		37,074
		Retail POS Systems & ATM Machines
	300,000	MPC Muechmeyer Petersen Capital		30,670
		Alternative Asset Manager
	250,000	Vossloh		29,346
		Rail Infrastructure & Diesel Locomotives
	15,000	Porsche		26,704
		Specialty Automobile Manufacturer
	525,000	GFK		25,928
		Market Research Services
	425,000	Hugo Boss Designs		25,446
		Fashion Apparel
	267,000	Elringklinger		24,359
		Automobile Components
	200,000	Deutsche Boerse		22,661
		Trading, Clearing, Settlement Services for Financial Markets
	100,000	Rational		19,595
		Commercial Oven Manufacturer
	870,000	Takkt		15,493
		Mail Order Retailer of Office & Warehouse Durables
	354,500	Deutsche Beteiligungs		14,384
		Private Equity Investment Management
				364,061
		> Switzerland 6.0%
	600,000	Kuehne & Nagel		55,263
		Freight Forwarding/Logistics
	24,000	Sika		48,983
		Chemicals for Construction & Industrial Applications
	140,000	Nobel Biocare Holding		45,713
		Dental Implants & Ceramic Crowns
	360,000	Synthes		43,207
		Products for Orthopedic Surgery
	250,000	Geberit		42,655
		Plumbing Supplies
	140,000	Burckhardt Compression (b)		33,925
		Gas Compression Pumps
	375,000	Schindler		24,862
		Elevator Manufacturer & Service Provider
	25,000	Givaudan		24,686
		Fragrances & Flavors
	400,000	Logitech International (b)		10,599
		Branded Peripheral Computer Devices
				329,893
		> United Kingdom 5.9%
	1,970,714	Expro International Group		38,416
		Offshore Oilfield Services
	1,875,000	Northgate		38,413
		Light Commercial Vehicle Rental Specialist

39

Columbia Acorn International

Statement of Investments (Unaudited), continued

Number of Shares			Value (000)
		> United Kingdom—continued
	5,040,000	RPS Group	$	35,304
		Environmental Consulting & Planning
	2,670,000	Smith & Nephew		33,041
		Medical Equipment & Supplies
	3,255,691	Tullow Oil		31,725
		Oil & Gas Producer
	5,922,000	Taylor Nelson Sofres		28,007
		Market Research
	3,007,000	BBA Group		16,307
		Aviation Support Services
	1,400,000	Informa Group		15,563
		Global Publisher & Event Organizer
	640,000	Randgold Resources		14,202
		Gold Mining in Western Africa
	650,000	Keller Group		14,020
		International Ground Engineering Specialist
	1,280,000	Workspace Group		10,262
		UK Real Estate
	517,000	Intertek Testing		10,136
		Testing, Inspection, Certification Services
	1,275,000	Detica		9,814
		UK IT Services Company
	1,436,000	Mears Group		9,347
		Social Housing Mainentance
	448,000	Rotork		8,174
		Valve Actuators for Oil & Water Pipelines
	1,000,000	Debt Free Direct		4,755
		Consumer Debt Reduction & Management Solutions
	371,000	Paragon Group		3,631
		UK Buy-to-let Finance Company
				321,117
		> Ireland 3.4%
	8,100,000	United Drug		44,231
		Irish Pharmaceutical Wholesaler & Outsourcer
	1,800,000	IAWS Group		37,705
		Baked Goods
	1,050,000	Kingspan Group		29,362
		Building Insulation & Environmental Containers
	1,300,000	Depfa Bank		23,018
		Investment Banker to Public Authorities
	600,000	Paddy Power		18,706
		Irish Betting Services
	845,000	Bank of Ireland		17,123
		Irish Commercial Bank
	1,040,000	Grafton Group		14,837
		Builders Materials Wholesaling & Do-it-yourself Retailing
	255,000	C&C Group		3,420
		Beverage Company
				188,402
		> Sweden 2.4%
	3,960,000	Hexagon		75,944
		Measurement Equipment & Polymers
	3,135,000	SWECO		30,042
		Engineering Consultants
	2,265,000	Nobia		28,189
		Kitchen Cabinet Manufacturing & Distribution
				134,175

Number of Shares			Value (000)
		> Italy 2.2%
	9,100,000	CIR	$	34,997
		Italian Holding Company
	12,531,048	Ducati Motor (b)		30,501
		Motorcycles & Related Merchandise
	3,000,000	Amplifon		24,927
		Hearing Aid Retailer
	1,223,000	GranitiFiandre		15,532
		Innovative Stoneware
	375,000	Sabaf		14,295
		Supplier to White Goods Original Equipment Manufacturers
				120,252
		> Spain 1.2%
	1,050,000	Prisa		23,092
		Leading Spanish-speaking Publisher
	520,000	Sogecable (b)		21,767
		Spain's Main Pay-TV
	400,000	Red Electrica de Espana		18,744
		Spanish Power Grid
				63,603
		> Austria 1.1%
	965,000	Zumtobel (b)		35,996
		Lighting Systems
	300,000	Wienerberger		22,123
		Bricks & Clay Roofing Tiles
				58,119
		> Russia 1.0%
	775,000	Novolipetsk Steel		22,746
		Vertically Integrated Steel Producer
	486,000	RosBusinessConsulting (b)		17,496
		Financial Information, Media & IT Services in Russia
	370,000	Mechel Steel Group		13,516
		Coking Coal
				53,758
		> Greece 1.0%
	1,630,000	Intralot		52,509
		Lottery & Gaming Systems & Services
				52,509
		> Poland 0.7%
	1,125,500	Central European Distribution (b)		38,965
		Vodka Production & Alcohol Distribution
				38,965
		> Finland 0.7%
	1,756,000	Poyry		38,934
		Engineering Consultants
				38,934
		> Czech Republic 0.6%
	183,000	Komercni Banka		34,069
		Leading Czech Universal Bank
				34,069
		> Denmark 0.6%
	265,000	Novozymes		30,719
		Industrial Enzymes
				30,719

40

Number of Shares			Value (000)
		> Norway 0.4%
	2,354,000	Kongsberg Automotive (a)	$	19,731
		Automotive Seating & Component Supplier
				19,731
Europe: Total				2,816,052
Asia 25.2%
		> Japan 13.3%
	6,000,000	Kansai Paint		52,411
		Paint Producer in Japan, India, China & Southeast Asia
	730,000	Ibiden		47,005
		Electronic Parts & Ceramics
	1,205,000	Aeon Mall		36,964
		Suburban Shopping Mall Developer, Owner & Operator
	43,500	Jupiter Telecommunications (b)		35,870
		Largest Cable Service Provider in Japan
	1,080,000	Hoya		35,745
		Opto-electrical Components & Eyeglass Lenses
	16,000	Kenedix		29,760
		Real Estate Investment Management
	1,218,000	JSR		29,334
		Films & Chemicals for LCD Screens & Electronics
	1,272,000	Ushio		28,184
		Industrial Light Sources
	1,300,000	Yusen Air & Sea Service		27,785
		Airfreight Logistics
	816,200	Kintetsu World Express		27,647
		Airfreight Logistics
	430,000	USS		27,369
		Used Car Auctioneer
	1,150,000	FCC		23,617
		Auto/Motorcycle Clutches
	718,000	Ito En		23,582
		Bottled Tea & Other Beverages
	2,000,000	Park24		20,081
		Parking Lot Operator
	7,000	Risa Partners		19,021
		NPL & Real Estate Related Investment
	500,000	Union Tool		18,471
		Precision Drill Bit Manufacturer
	14,000	FullCast (a)		18,403
		Employment Outsourcing
	145,000	Nakanishi		18,099
		Dental Tools & Machinery
	375,000	Daito Trust Construction		17,842
		Apartment Builder
	1,140,000	Cosel		16,520
		Industrial Standard Switching Power Supply System
	965,000	T. Hasegawa		16,064
		Industrial Flavors & Fragrances
	585,000	As One		15,068
		Scientific Supplies Distributor
	4,100,000	Kansai Urban Banking		14,215
		Regional Bank
	1,500,000	Chiba Bank		13,313
		Regional Bank

Number of Shares			Value (000)
	380,000	Takata	$	13,245
		Safety Related Auto Parts
	370,000	Shimano		12,679
		Bicycle Components & Fishing Tackle
	2,400	Osaka Securities Exchange		11,071
		Osaka Securities Exchange
	650,000	Topcon		10,818
		Positioning & Medical Instrument
	1,230,000	Kamigumi		10,662
		Port Cargo Handling & Logistics
	1,500,000	Bank of Fukuoka		9,895
		Regional Bank
	643,000	Ain Pharmaciez (a)		9,813
		Dispensing Pharmacy/Drugstore Operator
	72,000	Hirose Electric		9,457
		Electrical Connectors
	374,000	Nagaileben		7,215
		Medical/Health Care Related Clothes
	1,650	Japan Pure Chemical		6,486
		Precious Metal Plating Chemicals for Electronics
	3,300	Message		5,353
		Nursing Care Facility Operator
	105,000	Unicharm PetCare		4,228
		Pet Food & Pet Toiletries
	95,000	Aeon Delight		2,898
		Facility Maintenance & Management
	53,000	Hogy Medical		2,366
		Disposable Surgical Products
				728,556
		> China 3.9%
	23,547,000	China Shipping Development		54,313
		China's Dominant Shipper for Oil & Coal
	48,430,000	Lenovo Group		28,527
		Third Largest PC Vendor Globally
	25,051,000	China Green		23,071
		An Agricultural Grower & Processor in China
	6,256,000	Fu Ji Food & Catering Services		21,445
		Food Catering Service Provider In China
	20,000,000	Hopewell Highway Infrastructure		18,731
		Guangdong Tollroad Leading to Hong Kong & Macau
	17,918,000	Jiangsu Expressway		18,225
		Chinese Toll Road Operator
	20,910,000	Travelsky Technology		17,870
		Online Air Travel Bookings in China
	21,750,000	TPV Technology		15,035
		Original Design Manufacturer for LCD Monitor & Flat TV
	400,000	Sohu.com (b)		12,796
		Advertising on Chinese Internet Portal
	6,008,000	Xinyu Hengdeli		2,947
		A High-end Watch Retailer in China
				212,960
		> Hong Kong 2.2%
	5,500,000	Hong Kong Exchanges and Clearing		77,817
		Hong Kong Equity & Derivatives Market Operator
	29,344,000	EganaGoldpfeil		25,706
		A Leather & Fashion Accessories Brand Manager

41

Columbia Acorn International

Statement of Investments (Unaudited), continued

Number of Shares			Value (000)
		> Hong Kong—continued
	5,000,000	Lifestyle International	$	19,378
		Mid to High-end Department Store Operator in Hong Kong & China
				122,901
		> South Korea 1.7%
	444,000	Taewoong		31,144
		A Player in the Niche Customized Forging Market
	160,000	MegaStudy		31,081
		Online Education Service Provider
	915,000	Sung Kwang Bend		27,053
		A Large Customized Industrial Pipe Fitting Manufacturer
	262,000	YBM Sisa.com		5,031
		Online Language Educator & Tester
				94,309
		> India 1.5%
	1,300,000	Housing Development Finance		64,598
		Indian Mortgage Lender
	700,000	Asian Paints		14,250
		India's Largest Paint Company
	192,000	United Phosphorus		1,482
		Off-patent Crop Protection Chemicals
				80,330
		> Singapore 1.2%
	7,000,000	Singapore Exchange		44,707
		Singapore Equity & Derivatives Market Operator
	13,000,000	ComfortDelGro		18,527
		Taxi & Mass Transit Service
				63,234
		> Taiwan 1.1%
	6,958,367	Advantech		22,222
		Embedded Computers
	7,280,000	Wah Lee Industrial		16,478
		Distributor of Chemicals, Materials & Equipment
	3,500,000	Everlight Electronics		12,506
		A Led Packager
	795,826	Formosa International Hotels		8,565
		Hotel, Food & Beverage Operation & Hospitality Management Services
				59,771
		> Indonesia 0.3%
	15,000,000	Perusahaan Gas Negara		15,668
		Gas Pipeline Operator
				15,668
Asia: Total				1,377,729
Other Countries 10.4%
		> Australia 2.8%
	3,000,000	Billabong International		45,426
		Action Sports Apparel Brand Manager
	750,000	Australian Stock Exchange		30,851
		Australian Equity & Derivatives Market Operator
	2,000,000	Jubilee Mines		27,009
		Nickel Mining in Australia

Number of Shares			Value (000)
	5,480,000	Sino Gold (b)	$	25,957
		Gold Mining in The People's Republic of China
	350,000	Perpetual Trustees		23,183
		Mutual Fund Management
				152,426
		> Canada 2.6%
	1,860,000	ShawCor		57,114
		Oil & Gas Pipeline Products
	1,663,500	RONA (b)		34,746
		Leading Canadian Do-it-yourself Retailer
	950,000	Van Houtte (a)		22,188
		Coffee Services & Equipment
	865,000	Talisman Energy		16,727
		Oil & Gas Producer
	850,000	Ivanhoe Mines (b)		12,049
		Copper Mine Project in Mongolia
				142,824
		> United States 2.3%
	865,000	Atwood Oceanics (b)		59,356
		Offshore Drilling Contractor
	379,000	FMC Technologies (b)		30,024
		Oil & Gas Well Head Manufacturer
	500,000	Dresser-Rand Group (b)		19,750
		Largest Manufacturer of Compressors
	524,000	BioMarin (b)		9,401
		Biotech Focused on Orphan Diseases
	273,000	Tesco (b)		8,613
		Developing New Well Drilling Technologies
				127,144
		> South Africa 2.3%
	1,440,000	Impala Platinum Holdings		43,657
		Platinum Group Metals Mining & Refining
	1,560,000	Naspers		39,960
		Media & Education in Africa & Other Emerging Markets
	3,048,750	Uranium One (b)		38,837
		Uranium Mines in South Africa, Kazakhstan, Australia & the U.S.
				122,454
		> New Zealand 0.4%
	5,773,789	Sky City Entertainment		22,572
		Casino/Entertainment Complex
				22,572
Other Countries: Total				567,420
Latin America 4.7%
		> Brazil 2.6%
	4,300,000	Suzano		58,180
		Brazilian Pulp & Paper Producer
	2,500,000	Natura Cosmeticos		36,288
		Direct Retailer of Cosmetics
	720,000	Porto Seguro		27,621
		Auto & Life Insurance
	1,500,000	Localiza Rent A Car		16,913
		Car Rental
				139,002

42

Number of Shares or Principal Amount (000)			Value (000)
		> Mexico 1.6%
	7,000,000	Urbi Desarrollos Urbanos (b)	$	32,235
		Affordable Housing Builder
	18,000,000	Consorcio ARA		28,991
		Affordable Housing Builder
	500,000	Grupo Aeroportuario del Surest		26,345
		Cancun & Cozumel Airport Operator
				87,571
		> Chile 0.5%
	160,000	Sociedad Quimica y Minera de Chile		27,526
		Producer of Specialty Fertilizers, Lithium, & Iodine
				27,526
Latin America: Total				254,099
Total Equities: 91.9% (Cost: $3,002,695)				5,015,300
Short-Term Obligations 7.3%
$	27,200	Pasa Funding (c) 5.31% Due 7/13/07		27,152
	27,000	Advantage Asset (c) 5.32% Due 7/12/07		26,956
	27,000	Gotham Funding (c) 5.30% Due 7/16/07		26,940
	27,000	Mont Blanc Capital (c) 5.30% Due 7/24/07		26,909
	26,900	Beethoven Funding (c) 5.35% Due 7/23/07		26,812
	26,800	Coast Asset (c) 5.31% Due 7/11/07		26,761
	26,500	St. Germain Holdings (c) 5.33% Due 7/10/07		26,465
	26,400	Bavaria (c) 5.29% Due 7/5/07		26,384
	26,300	Mica Funding LLC (c) 5.29% Due 7/2/07		26,296
	26,300	Versailles LLC (c) 5.29% Due 7/3/07		26,292
	26,300	Whistlejacket Capital (c) 5.32% Due 7/9/07		26,269
	23,200	Morrigan TRR (c) 5.33% Due 7/17/07		23,145
	22,000	East Fleet Financial (c) 5.31% Due 7/6/07		21,984
	20,000	Manhattan Asset Funding (c) 5.31% Due 7/18/07		19,950
	18,000	Cairn High Grade LLC (c) 5.30% Due 7/20/07		17,950
	15,000	White Point Funding (c) 5.32% Due 7/19/07		14,960

Principal Amount (000)			Value (000)
$	7,601	Repurchase Agreement with Fixed Income Clearing Corp., dated 6/29/07, due 7/02/07 at 5.050%, collateralized by a U.S. Government Agency Obligation, maturing 7/18/11, market value $7,756 (repurchase proceeds $7,604)	$	7,601
		(Amortized Cost: $398,826)		398,826
Total Investments: 99.2% (Cost: $3,401,521)(d)(e)				5,414,126
Cash and Other Assets Less Liabilities: 0.8%				44,604
Total Net Assets: 100%			$	5,458,730

43

Columbia Acorn International

Statement of Investments (Unaudited), continued

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

(a)  An affiliate may include any company in which the Fund owns five percent or more of its outstanding voting shares. Transactions in these affiliated companies during the six months ended June 30, 2007, are as follows:

Affiliates	Balance of Shares Held 12/31/2006		Purchases/ Additions		Sales/ Reductions		Balance of Shares Held 6/30/2007		Value		Dividend
AIN Pharmaciez		643,000		-		-		643,000	$	9,813	$	91
FullCast		-		14,000		-		14,000		18,403		112
Kongsberg Automotive		2,065,000		289,000		-		2,354,000		19,731		386
Unit 4 Agresso		1,385,000		-		-		1,385,000		37,517		1,194
Van Houtte		950,000		-		-		950,000		22,188		245
TOTAL OF AFFILIATED TRANSACTIONS		5,043,000		303,000		-		5,346,000	$	107,652	$	2,028

  The aggregate cost and value of these companies at June 30, 2007, was $102,622 and $107,652, respectively. Investments in affiliate companies represented 2.0% of total net assets at June 30, 2007.

(b)  Non-income producing security.

(c)  Security exempt from registration under Section 4(2) of the Securities Act of 1933. These securities may only be resold in exempt transactions to qualified buyers. Private resales of these securities to qualified institutional buyers are also exempt from registration pursuant to Rule 144A under the Securities Act of 1933. At June 30, 2007, these securities amounted to $391,225, which represented 7.2% of net assets.

(d)  At June 30, 2007 for federal income tax purposes cost of investments was $3,401,521 and net unrealized appreciation was $2,012,605 consisting of gross unrealized appreciation of $2,090,136 and gross unrealized depreciation of $77,531.

(e)  On June 30, 2007, the Fund's total investments were denominated in currencies as follows:

Currency	Value		% of Total Net Assets
Euro	$	1,853,624		34.0	%
Japanese Yen		728,556		13.3
US Dollar		699,562		12.8
Swiss Franc		329,893		6.0
Hong Kong Dollar		323,065		5.9
British Pounds		306,915		5.6
Other currencies less than 5% of total net assets		1,172,511		21.6
	$	5,414,126		99.2	%

44

Columbia Acorn International

Portfolio Diversification

At June 30, 2007, the Fund's portfolio investments as a percent of net assets was diversified as follows:

	Value (000)		Percent
> Industrial Goods & Services
Materials & Specialty Chemicals	$	448,628		8.2	%
Other Industrial Services		328,110		6.0
Conglomerates		229,960		4.2
Machinery		209,206		3.9
Construction		148,935		2.7
Outsourcing & Training Services		126,130		2.3
Electrical Components		115,348		2.1
Industrial Distribution		29,905		0.6
Steel		22,746		0.4
		1,658,968		30.4
> Consumer Goods & Services
Food		131,411		2.4
Other Consumer Services		122,291		2.3
Durables Goods		121,041		2.2
Retail		109,397		2.0
Casinos		93,787		1.7
Apparels		70,872		1.3
Consumer Goods Distribution		66,334		1.2
Nondurables		66,222		1.2
Entertainment		46,736		0.9
Travel		34,783		0.6
Leisure Products		33,816		0.6
Furniture & Textiles		28,189		0.5
Consumer Electronics		15,035		0.3
		939,914		17.2
> Information
Financial Processors		145,185		2.7
Computer Hardware & Related Equipment		98,422		1.8
Business Information & Marketing Services		89,239		1.6
Satellite Broadcasting		64,665		1.2
Cable Television		57,637		1.0
Internet Related		52,200		1.0
Semiconductors & Related Equipment		48,251		0.9
Television Broadcasting		39,960		0.7
Publishing		38,655		0.7
Business Software		37,517		0.7
Computer Services		27,310		0.5
Electronics Distribution		16,478		0.3
Instrumentation		10,818		0.2
		726,337		13.3

	Value (000)		Percent
> Energy & Minerals
Oil Services	$	339,105		6.2
Mining		175,227		3.2
Agricultural Commodities		58,180		1.1
Oil/Gas Producers		48,452		0.9
Refining/Marketing/Distribution		45,379		0.8
		666,343		12.2
> Other Industries
Transportation		236,316		4.3
Real Estate		120,269		2.2
Regulated Utilities		53,741		1.0
		410,326		7.5
> Finance
Banks		111,633		2.0
Money Management		68,418		1.3
Savings & Loans		64,598		1.2
Insurance		46,058		0.8
Closed End Funds		30,670		0.6
Other Finance Companies		19,457		0.4
		340,834		6.3
> Health Care
Medical Equipment		121,961		2.2
Services		87,404		1.6
Pharmaceuticals		44,231		0.8
Hospital Laboratory Supplies		9,581		0.2
Biotechnology Drug Delivery		9,401		0.2
		272,578		5.0
Total Equities:		5,015,300		91.9
Short-Term Obligations:		398,826		7.3
Total Investments:		5,414,126		99.2
Cash and Other Assets Less Liabilities:		44,604		0.8
Net Assets:	$	5,458,730		100.0	%

45

Columbia Acorn USA

Major Portfolio Changes in the Second Quarter (Unaudited)

	Number of Shares
	03/31/07		06/30/07
Additions
Information
AMIS Holdings		401,000		601,000
Blackbaud		0		177,906
Ciena		0		85,000
Microsemi		450,000		570,000
Polycom		305,000		475,000
Tellabs		2,285,000		2,585,000
TheStreet.com		0		507,897
Time Warner Telecom		1,386,000		1,486,000
Trimble Navigation		310,000		368,000
Consumer Goods & Services
Cavco Industries		225,000		287,900
Hansen Natural		0		90,000
NutriSystem		99,000		149,000
Pinnacle Entertainment		160,000		340,000
Pool		318,500		523,500
Industrial Goods & Services
American Commercial Lines		0		340,000
American Reprographics		116,000		196,000
Drew Industries		100,000		155,000
Genlyte Group		440,000		480,000
Interline Brands		150,000		225,000
Health Care
Array Biopharma		0		244,094
BioMarin		440,000		692,400
Collagenex Pharmaceuticals		200,000		300,000
Genitope		0		450,000
Medarex		0		204,400
Pharmacopeia		0		220,000
Seattle Genetics		0		251,400
Finance
MB Financial		0		105,000
Old Second Bancorp		0		75,000
Pacific Continental		170,000		308,000
Energy & Minerals
Carrizo Oil & Gas		0		120,000
Tesco		57,500		95,000
Tetra Technologies		0		71,000

	Number of Shares
	03/31/07		06/30/07
Sales
Information
Alltel		270,000		0
Gemstar-TV Guide International		2,580,000		0
JDA Software		524,000		0
Kronos		660,650		0
Supertex		220,000		189,296
TALX		100,000		0
THQ		60,000		0
Consumer Goods & Services
Carter's		600,200		300,000
Central Parking		296,700		0
HNI		106,000		45,800
ITT Educational Services		416,000		366,000
Industrial Goods & Services
K&F Industries		236,400		0
Health Care
The Medicines Company		400,000		0
United Surgical Partners		550,000		0
Viasys Healthcare		220,000		0
Finance
Anchor Bancorp Wisconsin		141,400		111,400
Energy & Minerals
St. Mary Land & Exploration		80,000		47,000

46

Columbia Acorn USA

Statement of Investments (Unaudited), June 30, 2007

Number of Shares			Value (000)
				Equities: 96.2%
Information 30.9%
		> Business Software 4.8%
	779,900	Avid Technology (a)	$	27,569
		Digital Nonlinear Editing Software & Systems
	355,000	Micros Systems (a)		19,312
		Information Systems for Restaurants & Hotels
	2,100,000	Novell (a)		16,359
		Directory, Operating System & Identity Management Software
	327,200	Parametric Technology (a)		7,071
		Engineering Software & Services
	230,400	Concur Technologies (a)		5,265
		Web Enabled Cost & Expense Management Software
	177,906	Blackbaud		3,928
		Software & Services for Non-profits
	250,000	Agile Software (a)		2,015
		Product Design Software
				81,519
		> Mobile Communications 4.5%
	1,005,000	Crown Castle International (a)		36,451
		Communications Towers
	506,000	American Tower (a)		21,252
		Communications Towers in USA & Mexico
	1,633,000	Dobson Communications (a)		18,143
		Rural & Small City Cellular Telephone Services
	88,000	Globalstar (a)		911
		Satellite Mobile Voice & Data Carrier
	75,000	Openwave Systems		469
		Internet Software for Mobile Devices
				77,226
		> Semiconductors & Related Equipment 3.8%
	1,298,490	Integrated Device Technology (a)		19,828
		Communications Semiconductors
	570,000	Microsemi (a)		13,651
		Analog/Mixed Signal Semiconductors
	1,050,000	Entegris (a)		12,474
		Semiconductor Wafer Shipping & Handling Products
	601,000	AMIS Holdings (a)		7,524
		Mixed-signal Semiconductors
	189,296	Supertex (a)		5,933
		Mixed-signal Semiconductors
	140,000	Littelfuse (a)		4,728
		Little Fuses
				64,138
		> Computer Hardware & Related Equipment 3.3%
	433,581	Nice Systems (a)		15,063
		Audio & Video Recording Solutions
	505,000	II-VI (a)		13,721
		Laser Components
	295,600	Amphenol		10,538
		Electronic Connectors
	130,000	Belden CDT		7,195
		Specialty Cable
	99,000	Zebra Technologies (a)		3,835
		Bar Code Printers

Number of Shares			Value (000)
	90,000	Netgear (a)	$	3,263
		Networking Products for Small Business & Home
	65,000	Intermec (a)		1,645
		Bar Code & Wireless LAN Systems
	40,000	Rogers (a)		1,480
		PCB Laminates & High-performance Foams
				56,740
		> Telecommunications Equipment 2.9%
	2,585,000	Tellabs (a)		27,815
		Telecommunications Equipment
	475,000	Polycom (a)		15,960
		Video Conferencing Equipment
	85,000	Ciena (a)		3,071
		Optical Transport & Broadband Access Equipment
	323,500	Symmetricom (a)		2,717
		Network Timing & Synchronization Devices
				49,563
		> Instrumentation 2.8%
	430,000	Flir Systems (a)		19,887
		Infrared Cameras
	140,000	Mettler Toledo (a)		13,371
		Laboratory Equipment
	368,000	Trimble Navigation (a)		11,850
		GPS-based Instruments
	60,000	FARO Technologies (a)		1,912
		Precision Measurement Equipment
				47,020
		> Telephone Services 2.0%
	1,486,000	Time Warner Telecom (a)		29,869
		Fiber Optic Telephone/Data Services
	340,000	Windstream		5,018
		Rural Telephone Franchises
				34,887
		> Internet Related 1.6%
	460,000	ValueClick (a)		13,552
		Internet Advertising
	980,000	CNET Networks (a)		8,026
		Internet Advertising on Niche Websites
	507,897	TheStreet.com		5,526
		Financial Information Website Publisher
				27,104
		> Business Information & Marketing Services 1.2%
	530,000	Ceridian (a)		18,550
		HR Services & Payment Processing
	98,300	Navigant Consulting (a)		1,824
		Financial Consulting Firm
				20,374
		> Financial Processors 0.9%
	393,280	Global Payments		15,594
		Credit Card Processor
				15,594
		> Computer Services 0.8%
	786,000	RCM Technologies (a)(b)		6,123
		Technology & Engineering Services
	1,005,500	AnswerThink (a)		3,640
		IT Integration & Best Practice Research

47

Columbia Acorn USA

Statement of Investments (Unaudited), continued

Number of Shares			Value (000)
		> Computer Services—continued
	95,000	SRA International (a)	$	2,399
		Government IT Services
	235,000	iGate (a)		1,885
		IT & Business Process Outsourcing Services
				14,047
		> TV Broadcasting 0.7%
	1,125,000	Entravision Communications (a)		11,734
		Spanish Language TV, Radio & Outdoor
				11,734
		> Radio 0.7%
	511,100	Salem Communications		5,668
		Radio Stations for Religious Programming
	705,500	Spanish Broadcasting System (a)		3,034
		Spanish Language Radio Stations
	300,000	Saga Communications (a)		2,940
		Radio Stations in Small- & Mid-sized Cities
				11,642
		> Television Programming 0.5%
	750,000	Lions Gate Entertainment (a)		8,273
		Film & TV Studio
				8,273
		> CATV 0.3%
	240,000	Discovery Holding (a)		5,518
		CATV Programming
				5,518
		> Gaming Equipment & Services 0.1%
	98,500	Shuffle Master (a)		1,635
		Card Shufflers & Casino Games
				1,635
Information: Total				527,014
Consumer Goods & Services 20.4%
		> Retail 4.4%
	398,000	Abercrombie & Fitch		29,046
		Teen Apparel Retailer
	418,000	Chico's FAS (a)		10,174
		Women's Specialty Retailer
	175,000	J Crew Group (a)		9,466
		Multi-channel Branded Retailer
	486,250	Christopher & Banks		8,339
		Women's Apparel Retailer
	224,500	AnnTaylor Stores (a)		7,952
		Women's Apparel Retailer
	95,000	Genesco (a)		4,969
		Multi-concept Branded Footwear Retailer
	200,000	Urban Outfitters (a)		4,806
		Apparel & Home Specialty Retailer
				74,752
		> Apparel 3.9%
	634,200	Oxford Industries		28,121
		Branded & Private Label Apparel
	885,200	True Religion Apparel (a)		17,996
		Premium Denim
	222,200	Coach (a)		10,530
		Designer & Retailer of Branded Leather Accessories

Number of Shares			Value (000)
	300,000	Carter's (a)	$	7,782
		Children's Branded Apparel
	90,000	Heelys (a)		2,327
		Wheeled Footwear
				66,756
		> Other Consumer Services 3.8%
	366,000	ITT Educational Services (a)		42,961
		Post-secondary Degree Programs
	149,000	NutriSystem (a)		10,406
		Weight Loss Programs
	310,000	Universal Technical Institute (a)		7,871
		Vocational Training
	60,000	Weight Watchers International		3,051
		Weight Loss Programs
				64,289
		> Other Durable Goods 1.8%
	2,078,300	Champion Enterprises (a)		20,430
		Manufactured Homes
	287,900	Cavco Industries (a)		10,802
		Higher End Manufactured Homes
				31,232
		> Leisure Products 1.8%
	301,300	International Speedway		15,882
		Largest Motorsports Racetrack Owner & Operator
	195,500	Speedway Motorsports		7,816
		Motorsport Racetrack Owner & Operator
	80,000	Thor Industries		3,611
		RV & Bus Manufacturer
	50,000	Polaris Industries		2,708
		Leisure Vehicles & Related Products
				30,017
		> Nondurables 1.6%
	531,400	Scotts Miracle-Gro		22,819
		Consumer Lawn & Garden Products
	108,000	Jarden (a)		4,645
		Branded Household Products
				27,464
		> Consumer Goods Distribution 1.2%
	523,500	Pool		20,432
		Distributor of Swimming Pool Supplies & Equipment
				20,432
		> Restaurants 0.8%
	337,500	Sonic (a)		7,465
		Quick Service Restaurant
	163,800	Red Robin Gourmet Burgers (a)		6,613
		Casual Dining Restaurant
				14,078
		> Casinos & Gaming 0.6%
	340,000	Pinnacle Entertainment (a)		9,571
		Regional Casino Operator
				9,571
		> Food & Beverage 0.2%
	90,000	Hansen Natural (a)		3,868
		Alternative Beverages
				3,868

48

Number of Shares			Value (000)
		> Furniture & Textiles 0.2%
	45,800	HNI	$	1,878
		Office Furniture & Fireplaces
	56,800	Knoll		1,272
		Office Furniture
				3,150
		> Travel 0.1%
	45,000	Vail Resorts (a)		2,739
		Ski Resort Operator & Developer
				2,739
Consumer Goods & Services: Total				348,348
Industrial Goods & Services 14.0%
		> Machinery 6.9%
	697,500	Ametek		27,677
		Aerospace/Industrial Instruments
	673,600	Pentair		25,980
		Pumps & Water Treatment
	650,300	ESCO Technologies		23,580
		Automatic Electric Meter Readers
	373,600	Nordson		18,740
		Dispensing Systems for Adhesives & Coatings
	319,800	Donaldson		11,369
		Industrial Air Filtration
	71,800	Toro		4,228
		Turf Maintenance Equipment
	132,000	Goodman Global (a)		2,933
		HVAC Equipment Manufacturer
	50,000	Kaydon		2,606
		Specialized Friction & Motion Control Products
				117,113
		> Electrical Components 2.2%
	480,000	Genlyte Group (a)		37,699
		Commercial Lighting Fixtures
				37,699
		> Other Industrial Services 1.5%
	340,000	American Commercial Lines (a)		8,857
		Operator of Inland Barges/Builder of Inland Barges
	350,000	Labor Ready (a)		8,089
		Temporary Manual Labor
	196,000	American Reprographics (a)		6,035
		Document Management & Logistics
	89,000	G&K Services		3,516
		Uniform Rental
				26,497
		> Construction 1.0%
	204,050	Florida Rock		13,773
		Aggregates & Concrete
	100,000	Simpson Manufacturing		3,374
		Wall Joint Maker
				17,147
		> Outsourcing Services 1.0%
	350,000	Quanta Services (a)		10,734
		Electrical & Telecom Construction Services

Number of Shares			Value (000)
	175,000	Administaff	$	5,861
		Professional Employer Organization
				16,595
		> Industrial Distribution 0.6%
	225,000	Interline Brands (a)		5,868
		Industrial Distribution
	70,000	Watsco		3,808
		HVAC Distribution
				9,676
		> Waste Management 0.5%
	280,875	Waste Connections (a)		8,494
		Solid Waste Management
				8,494
		> Industrial Materials & Specialty Chemicals 0.3%
	155,000	Drew Industries (a)		5,137
		RV & Manufactured Home Components
				5,137
Industrial Goods & Services: Total				238,358
Health Care 11.8%
		> Biotechnology & Drug Delivery 4.4%
	885,000	PDL BioPharma (a)		20,620
		Proprietary Monoclonal Antibodies
	692,400	BioMarin (a)		12,422
		Biotech Focused on Orphan Diseases
	580,000	Nektar Therapeutics (a)		5,504
		Drug Delivery Technologies
	3,690,300	Medicure (a)		4,982
	738,060	Medicure - Warrants (a)(c)		443
		Cardiovascular Biotech Company
	125,000	Myriad Genetics (a)		4,649
		Drugs/Diagnostics Hybrid
	1,135,000	Decode Genetics (a)		4,239
		Drugs for Heart Attack, Asthma & Vascular Disease
	204,400	Medarex (a)		2,921
		Humanized Antibodies
	650,000	La Jolla Pharmaceutical (a)		2,912
		Lupus Treatment
	244,094	Array Biopharma (a)		2,849
		Drugs for Cancer & Inflammatory Diseases
	248,600	Arena Pharmaceuticals (a)		2,732
		Novel Drug Targeting Technology
	500,000	IsoRay (a)		2,520
	100,000	IsoRay - Warrants (a)(c)		114
		Radiology Cancer Company
	251,400	Seattle Genetics (a)		2,466
		Antibody-based Therapies for Cancer
	271,590	Neurogen (a)		1,803
		Development-stage Biotech Focused on Neurology
	450,000	Genitope (a)		1,737
		Cancer Vaccine
	220,000	Pharmacopeia (a)		1,221
		Biotech Company with Broad Early-stage Pipeline
	273,500	Nuvelo (a)		744
		Development-stage Biotech Focused on Cardiovascular/Cancer

49

Columbia Acorn USA

Statement of Investments (Unaudited), continued

Number of Shares			Value (000)
		> Biotechnology & Drug Delivery—continued
	375,000	Locus Discovery, Series D, Pfd. (a)(c)	$	109
	193,288	Locus Discovery, Series B, Pfd. (a)(c)		56
		High Throughput Rational Drug Design
	18,181	Metabolex (a)(c)		64
		Diabetes Drug Development
				75,107
		> Medical Equipment & Devices 2.2%
	577,400	Edwards Lifesciences (a)		28,489
		Heart Valves
	105,000	Vital Signs		5,833
		Anesthesia, Respiratory & Sleep Products
	94,171	Advanced Medical Optics (a)		3,284
		Medical Devices for Eye Care
				37,606
		> Health Care Services 2.2%
	291,800	Lincare Holdings (a)		11,628
		Home Health Care Services
	210,000	LCA-Vision		9,925
		Lasik Surgery Centers
	470,000	PSS World Medical (a)		8,563
		Medical Supplies
	137,000	Charles River Laboratories (a)		7,072
		Pharmaceutical Research
				37,188
		> Pharmaceuticals 1.6%
	250,000	Medicis Pharmaceutical		7,635
		Specialty Pharmaceuticals-dermatology
	270,000	MGI Pharma (a)		6,040
		Specialty Pharmaceuticals for Oncology & Acute Care
	790,000	QLT (a)		5,846
		Specialty Pharmaceuticals for Ophthalmology & Dermatology
	300,000	Collagenex Pharmaceuticals (a)		3,720
		Specialty Pharmaceuticals-dermatology
	505,000	Barrier Therapeutics (a)		3,283
		Specialty Pharmaceuticals for Dermatology
				26,524
		> Medical Supplies 1.4%
	270,700	ICU Medical (a)		11,624
		Intravenous Therapy Products
	158,300	Techne (a)		9,056
		Cytokines, Antibodies & other Reagents for Life Science
	104,000	Arrow International		3,981
		Disposable Catheters
				24,661
Health Care: Total				201,086
Finance 8.8%
		> Finance Companies 3.2%
	1,121,500	AmeriCredit (a)		29,776
		Auto Lending
	482,900	World Acceptance (a)		20,634
		Personal Loans
	130,000	McGrath Rentcorp		4,380
		Temporary Space & IT Rentals
				54,790

Number of Shares			Value (000)
		> Insurance 2.7%
	714,500	HCC Insurance Holdings	$	23,872
		Specialty Insurance
	14,000	Markel (a)		6,784
		Specialty Insurance
	105,000	Philadelphia Consolidated Holding (a)		4,389
		Specialty Insurance
	87,000	Delphi Financial Group		3,638
		Group Employee Benefit Products & Services
	75,000	Endurance Specialty Holdings		3,003
		Commercial Lines Insurance/Reinsurance
	177,743	Eastern Insurance Holdings		2,824
		Workers Comp & Specialty Insurance
	91,000	United America Indemnity (a)		2,263
		Specialty Insurance
				46,773
		> Banks 2.5%
	212,756	Chittenden		7,436
		New England Bank
	239,500	TCF Financial		6,658
		Great Lakes Bank
	308,000	Pacific Continental		4,989
		Niche Pacific N.W. Bank
	145,000	Greene County Bancshares		4,533
		Tennessee Bank
	215,000	First Busey		4,298
		Illinois Bank
	105,000	MB Financial		3,648
		Chicago Bank
	94,000	Associated Banc-Corp		3,074
		Midwest Bank
	125,000	Lakeland Financial		2,659
		Indiana Bank
	114,777	Glacier Bancorp		2,336
		Mountain States Bank
	75,000	Old Second Bancorp		2,187
		Illinois Bank
	20,000	First Financial Bankshares		776
		West Texas Bank
	31,500	West Bancorporation		503
		Des Moines Commercial Bank
				43,097
		> Savings & Loans 0.4%
	168,000	People's United		2,979
		Connecticut Savings & Loan
	111,400	Anchor Bancorp Wisconsin		2,917
		Wisconsin Thrift
				5,896
Finance: Total				150,556
Energy & Minerals 7.8%
		> Oil Services 4.3%
	401,700	FMC Technologies (a)		31,823
		Oil & Gas Well Head Manufacturer

50

Number of Shares			Value (000)
		> Oil Services—continued
	367,000	Atwood Oceanics (a)	$	25,184
		Offshore Drilling Contractor
	355,000	Hanover Compressor (a)		8,467
		Natural Gas Compressor Rental & Fabrication
	95,000	Tesco (a)		2,997
		Developing New Well Drilling Technologies
	67,500	CARBO Ceramics		2,957
		Natural Gas Well Stimulants
	71,000	Tetra Technologies (a)		2,002
		U.S.-based Services Company with Life of Field Approach
	11,000	Key Energy Services (a)		204
		Well Workover Services
				73,634
		> Oil & Gas Producers 2.8%
	525,000	Quicksilver Resources (a)		23,404
		Natural Gas & Coal Seam Gas Producer
	208,400	Southwestern Energy (a)		9,274
		Oil & Gas Producer
	111,200	Equitable Resources		5,511
		Natural Gas Producer & Utility
	120,000	Carrizo Oil & Gas (a)		4,976
		Explores for Natural Gas & Crude Oil
	450,000	Vaalco Energy (a)		2,174
		Oil & Gas Producer
	47,000	St. Mary Land & Exploration		1,721
		Oil & Gas Producer
				47,060
		> Other Resources 0.5%
	218,000	Layne Christensen (a)		8,927
		Oil & Gas Production/Engineering & Construction/Contract Drilling
				8,927
		> Oil Refining, Marketing & Distribution 0.2%
	50,250	Oneok		2,533
		Natural Gas Distribution, Pipeline Processing & Trading
				2,533
Energy & Minerals: Total				132,154
Other Industries 2.5%
		> Real Estate 1.8%
	560,000	DiamondRock Hospitality		10,685
		Hotel Owner
	350,000	Highland Hospitality		6,720
		Hotel Owner
	77,500	Gaylord Entertainment (a)		4,157
		Convention Hotels
	100,000	Digital Realty Trust		3,768
		Technology-focused Office Buildings
	150,000	Kite Realty Group		2,853
		Community Shopping Centers
	90,000	American Campus Communities		2,546
		Student Housing
				30,729

Number of Shares or Principal Amount (000)			Value (000)
		> Transportation 0.5%
	524,720	Heartland Express	$	8,553
		Regional Trucker
				8,553
		> Regulated Utilities 0.2%
	97,500	Northeast Utilities		2,765
		Regulated Electric Utility
				2,765
Other Industries: Total				42,047
Total Equities: 96.2% (Cost: $1,132,404)				1,639,563
Short-Term Obligations 5.3%
$	8,700	Pasa Funding (d) 5.31% Due 7/03/07		8,697
	8,700	World Omni Vehicle Leasing (d) 5.30% Due 7/06/07		8,693
	8,600	Times Square Funding (d) 5.30% Due 7/02/07		8,599
	8,600	Transamerica Asset (d) 5.40% Due 7/02/07		8,599
	8,600	Morrigan TRR (d) 5.23% Due 7/05/07		8,595
	8,600	Morrigan TRR (d) 5.34% Due 7/09/07		8,590
	8,600	Natixis (d) 5.33% Due 7/10/07		8,588
	8,500	Abbey National 5.29% Due 7/02/07		8,499
	8,500	Erste Finance LLC (d) 5.32% Due 7/02/07		8,499
	8,500	Mica Funding LLC 5 (d) 5.32% Due 7/02/07		8,499
	4,154	Repurchase Agreement with Fixed Income Clearing Corp., dated 6/29/07, due 7/02/07 at 5.050%, collateralized by a U.S. Government Agency Obligation, maturing 7/18/11, market value $4,238 (repurchase proceeds $4,156)		4,154
		(Amortized Cost: $90,012)		90,012
Total Investments: 101.5% (Cost: $1,222,416)(e)				1,729,575
Cash and Other Assets Less Liabilities: (1.5)%				(26,037	)
Total Net Assets: 100%			$	1,703,538

51

Columbia Acorn USA

Statement of Investments (Unaudited), continued

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

(a)  Non-income producing security.

(b)  An affiliate may include any company in which the Fund owns five percent or more of its outstanding voting shares. Transactions in this affiliated company during the six months ended June 30, 2007, are as follows:

Affiliate	Balance of Shares Held 12/31/2006		Purchases/ Additions		Sales/ Reductions		Balance of Shares Held 6/30/2007		Value		Dividend
RCM Technologies		786,000		-		-		786,000	$	6,123	$	-

  The aggregate cost and value of this company at June 30, 2007, was $3,130 and $6,123, respectively. Investments in affiliate companies represented 0.4% of total net assets at June 30, 2007.

(c)  Denotes a restricted security, which is subject to restrictions on resale under federal securities laws. These securities, are valued in good faith by the Board of Trustees. At June 30, 2007, these securities had an aggregate value of $786 which represented 0.05% of total net assets.

  Additional information on these securities is as follows:

Security	Acquisition Dates	Shares		Cost		Value
Locus Discovery, Series D, Pfd.	9/5/01		375,000	$	1,500	$	109
Locus Discovery, Series B, Pfd.	2/8/07		193,288		56		56
Metabolex, Series F	5/11/00		18,181		2,000		64
IsoRay Warrants	3/21/07		100,000		-		114
Medicure Warrants	12/22/06		738,060		-		443
				$	3,556	$	786

(d)  Security exempt from registration under Section 4(2) of the Securities Act of 1933. These securities may only be resold in exempt transactions to qualified buyers. Private resales of these securities to qualified institutional buyers are also exempt from registration pursuant to Rule 144A under the Securities Act of 1933. At June 30, 2007, these securities amounted to $77,359, which represented 4.5% of net assets.

(e)  At June 30, 2007, for federal income tax purposes cost of investments was $1,222,416 and net unrealized appreciation was $507,159 consisting of gross unrealized appreciation of $551,801 and gross unrealized depreciation of $44,642.

52

Columbia Acorn International Select

Major Portfolio Changes in the Second Quarter (Unaudited)

	Number of Shares
	03/31/07		06/30/07
Additions
Europe
> Switzerland
Geberit		2,400		24,000
Kuehne & Nagel		49,000		70,000
Synthes		50,500		57,000
> Netherlands
Fugro		60,000		125,634
SBM Offshore		0		60,000
Stork		0		79,000
Wavin		0		44,936
> Ireland
CRH		140,000		146,737
United Drug		710,733		751,000
> United Kingdom
Informa Group		0		170,000
Intertek Testing		0		71,700
Smith & Nephew		441,000		535,000
> Austria
Zumtobel		172,500		189,500
> Greece
Intralot		60,000		130,000
Asia
> Japan
Hoya		140,000		153,000
Kansai Paint		280,000		540,000
Nintendo		21,500		29,700
> Hong Kong
Hong Kong Exchanges and Clearing		405,000		500,000
Other Countries
> United States
Atwood Oceanics		97,500		100,000

	Number of Shares
	03/31/07		06/30/07
Sales
Europe
> Ireland
Anglo Irish Bank		160,000		0
Bank of Ireland		240,000		65,000
C&C Group		100,800		24,700
Ryanair		85,000		0
> United Kingdom
Northern Rock		215,000		0
Paragon Group		310,000		0
> Spain
Red Electrica de Espana		90,000		85,000
> Italy
Banca Italease		30,000		0
Asia
> Japan
Daito Trust Construction		68,000		43,000
USS		40,000		32,000

53

Columbia Acorn International Select

Statement of Investments (Unaudited), June 30, 2007

Number of Shares			Value (000)
				Equities: 91.7%
Europe 51.4%
		> Switzerland 12.0%
	57,000	Synthes	$	6,841
		Products for Orthopedic Surgery
	70,000	Kuehne & Nagel		6,447
		Freight Forwarding/Logistics
	16,500	Nobel Biocare Holding		5,388
		Dental Implants & Ceramic Crowns
	24,000	Geberit		4,095
		Plumbing Supplies
	7,500	Swatch Group		2,130
		Watch & Electronics Manufacturer
	26,000	Schindler		1,724
		Elevator Manufacturer & Service Provider
				26,625
		> Netherlands 10.0%
	125,634	Fugro		7,973
		Oilfield Services
	79,000	Stork		5,128
		Industrial Services & Food Processing Equipment
	117,633	Aalberts Industries		3,230
		Flow Control & Heat Treatment
	60,000	SBM Offshore		2,287
		Builds & Leases Offshore Vessels to Process & Store Crude Oil
	34,723	USG People		1,631
		Temporary Staffing Services
	44,936	Wavin		1,081
		Largest European Plastic Pipe Systems Company
	23,100	Boskalis Westminster		919
		Dredging & Maritime Contractor
				22,249
		> Ireland 7.3%
	146,737	CRH		7,242
		Global Building Materials
	751,000	United Drug		4,101
		Irish Pharmaceutical Wholesaler & Outsourcer
	150,000	IAWS Group		3,142
		Baked Goods
	65,000	Bank of Ireland		1,317
		Irish Commercial Bank
	24,700	C&C Group		331
		Beverage Company
				16,133
		> United Kingdom 4.5%
	535,000	Smith & Nephew		6,620
		Medical Equipment & Supplies
	170,000	Informa Group		1,890
		Global Publisher & Event Organizer
	71,700	Intertek Testing		1,406
		Testing, Inspection, Certification Services
				9,916
		> Germany 3.5%
	40,000	Wincor Nixdorf		3,708
		Retail POS Systems & ATM Machines
	1,250	Porsche		2,225
		Specialty Automobile Manufacturer

Number of Shares			Value (000)
	17,000	Deutsche Boerse	$	1,926
		Trading, Clearing, Settlement Services for Financial Markets
				7,859
		> Austria 3.2%
	189,500	Zumtobel (a)		7,069
		Lighting Systems
				7,069
		> France 2.9%
	300,000	SES Global		6,466
		Satellite Broadcasting Services
				6,466
		> Sweden 2.7%
	318,000	Hexagon		6,098
		Measurement Equipment & Polymers
				6,098
		> Greece 1.9%
	130,000	Intralot		4,188
		Lottery & Gaming Systems & Services
				4,188
		> Spain 1.8%
	85,000	Red Electrica de Espana		3,983
		Spanish Power Grid
				3,983
		> Denmark 1.6%
	31,000	Novozymes		3,593
		Industrial Enzymes
				3,593
Europe: Total				114,179
Asia 28.4%
		> Japan 23.4%
	29,700	Nintendo		10,847
		Entertainment Software & Hardware
	6,700	Jupiter Telecommunications (a)		5,525
		Largest Cable Service Provider in Japan
	153,000	Hoya		5,064
		Opto-electrical Components & Eyeglass Lenses
	2,700	Kenedix		5,022
		Real Estate Investment Management
	77,000	Ibiden		4,958
		Electronic Parts & Ceramics
	160,000	Aeon Mall		4,908
		Suburban Shopping Mall Developer, Owner & Operator
	540,000	Kansai Paint		4,717
		Paint Producer in Japan, India, China & Southeast Asia
	143,700	JSR		3,461
		Films & Chemicals for LCD Screens & Electronics
	43,000	Daito Trust Construction		2,046
		Apartment Builder
	32,000	USS		2,037
		Used Car Auctioneer
	85,000	Ushio		1,883
		Industrial Light Sources

54

Number of Shares			Value (000)
		> Japan—continued
	138,000	Park24	$	1,385
		Parking Lot Operator
				51,853
		> Hong Kong 3.2%
	500,000	Hong Kong Exchanges and Clearing		7,074
		Hong Kong Equity & Derivatives Market Operator
				7,074
		> Singapore 1.8%
	630,000	Singapore Exchange		4,024
		Singapore Equity & Derivatives Market Operator
				4,024
Asia: Total				62,951
Other Countries 11.9%
		> Canada 4.8%
	90,000	Potash Corp. of Saskatchewan		7,017
		World's Largest Producer of Potash
	174,400	RONA (a)		3,643
		Leading Canadian Do-it-yourself Retailer
				10,660
		> South Africa 4.0%
	151,300	Impala Platinum Holdings		4,587
		Platinum Group Metals Mining & Refining
	165,000	Naspers		4,227
		Media & Education in Africa & Other Emerging Markets
				8,814
		> United States 3.1%
	100,000	Atwood Oceanics (a)		6,862
		Offshore Drilling Contractor
				6,862
Other Countries: Total				26,336
Total Equities: 91.7% (Cost: $156,119)				203,466

Principal Amount (000)			Value (000)
Short-Term Obligation 7.4%
$	16,495	Repurchase Agreement with Fixed Income Clearing Corp., dated 6/29/07, due 7/02/07 at 5.050%, collateralized by a U.S. Government Agency Obligation, maturing 7/18/11, market value $16,825 (repurchase proceeds $16,502)	$	16,495
		(Amortized Cost: $16,495)		16,495
Total Investments: 99.1% (Cost: $172,614)(b)(c)				219,961
Cash and Other Assets Less Liabilities: 0.9%				2,031
Total Net Assets: 100%			$	221,992

55

Columbia Acorn International Select Fund

Statement of Investments (Unaudited), continued

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

(a)  Non-income producing security.

(b)  At June 30, 2007, for federal income tax purposes cost of investments was $172,614 and net unrealized appreciation was $47,347 consisting of gross unrealized appreciation of $51,104 and gross unrealized depreciation of $3,757.

(c)  On June 30, 2007, the Fund's total investments were denominated in currencies as follows:

Currency	Value		% of Net Assets
Euro	$	67,946		30.6	%
Japanese Yen		51,853		23.4
US Dollar		30,374		13.7
Swiss Franc		26,625		12.0
Other currencies less than 5% of total net assets		43,163		19.4
	$	219,961		99.1	%

56

Columbia Acorn International Select

Portfolio Diversification

At June 30, 2007, the Fund's portfolio investments as a percent of net assets was diversified as follows:

	Value (000)		Percent
> Industrial Goods & Services
Conglomerates	$	19,414		8.8	%
Construction		13,383		6.0
Specialty Chemicals		12,852		5.8
Other Industrial Services		9,577		4.3
Electrical Components		8,952		4.0
Outsourcing Services		1,631		0.7
		65,809		29.6
> Information
Financial Processors		13,024		5.9
Domestic Consumer Software		10,847		4.9
Satellite Broadcasting		6,466		2.9
Cable Television		5,525		2.5
Semiconductors & Related Equipment		5,064		2.3
Television Broadcasting		4,227		1.9
Computer Hardware & Related Equipment		3,708		1.7
Publishing		1,890		0.8
		50,751		22.9
> Energy & Minerals
Oil/Gas Producers		18,041		8.1
Mining		11,604		5.3
		29,645		13.4

	Value (000)		Percent
> Consumer Goods & Services
Retail	$	8,551		3.8
Durable Goods		4,355		2.0
Casinos		4,188		1.9
Food		3,473		1.6
Consumer Goods Distribution		2,037		0.9
Consumer Services		1,385		0.6
		23,989		10.8
> Health Care
Medical Equipment		18,849		8.5
Pharmaceuticals		4,101		1.8
		22,950		10.3
> Other Industries
Real Estate		5,022		2.3
Regulated Utilities		3,983		1.8
		9,005		4.1
> Finance
Banks		1,317		0.6
		1,317		0.6
Total Equities:		203,466		91.7
Short-Term Obligations:		16,495		7.4
Total Investments:		219,961		99.1
Cash and Other Assets Less Liabilities:		2,031		0.9
Net Assets:	$	221,992		100.0	%

57

Columbia Acorn Select

Major Portfolio Changes in the Second Quarter (Unaudited)

	Number of Shares
	03/31/07		06/30/07
Additions
Consumer Goods & Services
Chico's FAS		1,811,000		2,000,000
Hertz		1,750,000		2,000,000
Information
Globalstar		3,514,300		6,000,000
Liberty Global Series C		2,963,800		3,000,000
Sanmina-SCI		11,000,000		16,021,480
Tellabs		11,300,000		13,757,500
Energy & Minerals
Atwood Oceanics		400,000		500,000
Tetra Technologies		0		2,000,000
Finance
Conseco		5,800,000		6,550,000
Janus Capital Group		3,450,000		4,050,000
Montpelier Re		1,000,000		2,000,000
Industrial Goods & Services
American Commercial Lines		0		2,068,400
Worthington Industries		2,250,000		2,350,000
Other Industries
JB Hunt Transport Services		0		1,000,000

	Number of Shares
	03/31/07		06/30/07
Sales
Consumer Goods & Services
ITT Educational Services		1,475,000		1,300,000
Weight Watchers International		238,200		0
Finance
Nuveen Investments		975,000		0
Industrial Goods & Services
Quanta Services		3,030,000		2,700,000

58

Columbia Acorn Select

Statement of Investments (Unaudited), June 30, 2007

Number of Shares			Value (000)
				Equities: 89.7%
Consumer Goods & Services 26.5%
		> Retail 10.6%
	3,550,000	Safeway	$	120,806
		Supermarkets
	1,650,000	Abercrombie & Fitch		120,417
		Teen Apparel Retailer
	850,000	Costco Wholesale		49,742
		Warehouse Superstores
	2,000,000	Chico's FAS (a)		48,680
		Women's Specialty Retail
				339,645
		> Other Consumer Services 6.0%
	1,300,000	ITT Educational Services (a)		152,594
		Post-secondary Degree Programs
	1,500,000	Universal Technical Institute (a)(b)		38,085
		Vocational Training
				190,679
		> Travel 4.9%
	3,550,000	Expedia (a)		103,979
		Online Travel Services Company
	2,000,000	Hertz (a)		53,140
		Largest U.S. Rental Car Operator
				157,119
		> Leisure Products 2.7%
	800,000	Harley-Davidson		47,688
		Motorcycles & Related Merchandise
	750,000	International Speedway		39,533
		Largest Motorsports Racetrack Owner & Operator
				87,221
		> Apparel 2.3%
	1,550,000	Coach (a)		73,455
		Designer & Retailer of Branded Leather Accessories
				73,455
Consumer Goods & Services: Total				848,119
Information 25.6%
		> CATV 6.6%
	3,000,000	Liberty Global Series C (a)		117,900
	600,000	Liberty Global Series A (a)		24,624
		Cable TV Franchises Outside the USA
	3,000,000	Discovery Holding (a)		68,970
		CATV Programming
				211,494
		> Mobile Communications 4.9%
	2,300,000	American Tower (a)		96,600
		Communications Towers in USA & Mexico
	6,000,000	Globalstar (a)(b)		62,100
		Satellite Mobile Voice & Data Carrier
				158,700
		> Telecommunications Equipment 4.6%
	13,757,500	Tellabs (a)		148,031
		Telecommunications Equipment
				148,031

Number of Shares			Value (000)
		> Business Software 4.2%
	2,350,000	Avid Technology (a)(b)	$	83,072
		Digital Nonlinear Editing Software & Systems
	6,500,000	Novell (a)		50,635
		Directory, Operating System & Identity Management Software
				133,707
		> Internet Related 2.8%
	9,600,000	SkillSoft (a)(b)		89,184
		Web-based Learning Solutions (E-Learning)
				89,184
		> Contract Manufacturing 1.6%
	16,021,480	Sanmina-SCI (a)		50,147
		Electronic Manufacturing Services
				50,147
		> Semiconductors & Related Equipment 0.8%
	2,700,000	Canadian Solar (a)(b)		25,380
		Solar Cell & Module Manufacturer
				25,380
		> Computer Services 0.1%
	1,367,000	AnswerThink (a)		4,949
		IT Integration & Best Practice Research
				4,949
Information: Total				821,592
Energy & Minerals 14.1%
		> Mining 9.8%
	15,666,000	Uranium One (South Africa) (a)		199,566
		Uranium Mines in South Africa, Kazakhstan, Australia & the U.S.
	1,440,000	Potash Corp. of Saskatchewan (Canada)		112,277
		World's Largest Producer of Potash
				311,843
		> Oil Services 4.3%
	2,000,000	Tetra Technologies (a)		56,400
		U.S. Based Service Company with Life of Field Approach
	600,000	FMC Technologies (a)		47,532
		Oil & Gas Well Head Manufacturer
	500,000	Atwood Oceanics (a)		34,310
		Offshore Drilling Contractor
				138,242
Energy & Minerals: Total				450,085
Finance 12.0%
		> Insurance 7.1%
	6,550,000	Conseco (a)		136,829
		Life, Long-term Care & Medical Supplement Insurance
	112,000	Markel (a)		54,271
		Specialty Insurance
	2,000,000	Montpelier Re		37,080
		Commercial Lines Insurance/Reinsurance
				228,180

59

Columbia Acorn Select

Statement of Investments (Unaudited), continued

Number of Shares or Principal Amount (000)			Value (000)
		> Brokerage & Money Management 4.9%
	4,050,000	Janus Capital Group	$	112,752
		Manages Mutual Funds
	1,500,000	SEI Investments		43,560
		Mutual Fund Administration & Investment Management
				156,312
Finance: Total				384,492
Industrial Goods & Services 9.5%
		> Other Industrial Services 3.5%
	1,425,000	Expeditors International of Washington		58,852
		International Freight Forwarder
	2,068,400	American Commercial Lines (a)		53,882
		Operator of Inland Barges/Builder of Inland Barges
				112,734
		> Outsourcing Services 2.6%
	2,700,000	Quanta Services (a)		82,809
		Electrical & Telecom Construction Services
				82,809
		> Waste Management 1.8%
	1,500,000	Waste Management		58,575
		U.S. Garbage Collection & Disposal
				58,575
		> Steel 1.6%
	2,350,000	Worthington Industries		50,878
		Steel Processing & Manufactured Metal Products
				50,878
Industrial Goods & Services: Total				304,996
Health Care 1.1%
		> Health Care Services 1.1%
	910,000	Lincare Holdings (a)		36,263
		Home Health Care Services
				36,263
Health Care: Total				36,263
Other Industries 0.9%
		> Transportation 0.9%
	1,000,000	JB Hunt Transport Services		29,320
		Truck & Intermodal Carrier
				29,320
Other Industries: Total				29,320
Total Equities: 89.7% (Cost: $1,841,270)				2,874,867
Short-Term Obligations 10.0%
$	15,900	Natixis (c) 5.33% Due 7/11/07		15,876
	15,900	Giro Balanced Funding (c) 5.30% Due 7/20/07		15,856

Principal Amount (000)			Value (000)
$	15,900	Old Court Funding (c) 5.35% Due 7/26/07	$	15,841
	15,900	Keel Capital (c) 5.30% Due 7/27/07		15,839
	15,800	Ebury Finance Ltd. (c) 5.30% Due 7/5/07		15,791
	15,800	World Omni Vehicle Leasing (c) 5.30% Due 7/24/07		15,747
	15,700	Anglesea Funding (c) 5.29% Due 7/2/07		15,698
	15,700	Mainsail II Ltd. (c) 5.28% Due 7/3/07		15,695
	15,700	Austra (c) 5.28% Due 7/6/07		15,688
	15,700	White Point Funding (c) 5.32% Due 7/18/07		15,661
	15,700	Hannover Funding (c) 5.30% Due 7/19/07		15,658
	15,700	Coast Asset (c) 5.31% Due 7/23/07		15,649
	15,700	Liberty Street Funding (c) 5.33% Due 7/25/07		15,644
	15,600	Whistlejacket Capital (c) 5.29% Due 7/9/07		15,582
	15,500	Mica Funding LLC (c) 5.34% Due 7/13/07		15,472
	15,400	TSL USA (c) 5.30% Due 7/10/07		15,380
	15,400	La Fayette Asset Securitization LLC (c) 5.28% Due 7/11/07		15,377
	15,300	Bavaria (c) 5.31% Due 7/12/07		15,275
	15,000	Morrigan TRR (c) 5.34% Due 7/16/07		14,967
	15,000	Manhattan Asset Funding (c) 5.29% Due 7/17/07		14,965
	9,916	Repurchase Agreement with Fixed Income Clearing Corp., dated 6/29/07, due 7/2/07 at 5.050%, collateralized by a U.S. Government Agency Obligation, maturing 7/18/11, market value of $10,118 (repurchase proceeds $9,920)		9,916
		(Amortized Cost: $321,577)		321,577
Total Investments: 99.7% (Cost: $2,162,847)(d)				3,196,444
Cash and Other Assets Less Liabilities: 0.3%				9,698
Total Net Assets: 100%			$	3,206,142

60

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

(a)  Non-income producing security.

(b)  An affiliate may include any company in which the Fund owns five percent or more of its outstanding voting shares. Transactions in these affiliated companies during the six months ended June 30, 2007, are as follows:

Affiliates	Balance of Shares Held 12/31/06		Purchases/ Additions		Sales/ Reductions		Balance of Shares Held 6/30/07		Value		Dividend
Avid Technology		2,200,000		150,000		-		2,350,000	$	83,073	$	-
Canadian Solar		550,000		2,150,000		-		2,700,000		25,380		-
Globalstar		1,600,000		4,400,000		-		6,000,000		62,100		-
SkillSoft		9,600,000		-		-		9,600,000		89,184		-
Universal Technical Institute		1,350,000		150,000		-		1,500,000		38,085		-
UrAsia Energy (merged into Uranium One)*		30,050,000		2,000,000		32,050,000		-		-		-
TOTAL OF AFFILIATED TRANSACTIONS		45,350,000		8,850,000		32,050,000		22,150,000	$	297,822	$	-

*  At June 30, 2007, the Fund owned less than five percent of the company's outstanding voting shares.

  The aggregate cost and value of these companies at June 30, 2007, was $226,635 and $297,822, respectively. Investments in affiliate companies represented 9.3% of total net assets at June 30, 2007.

(c)  Security exempt from registration under Section 4(2) of the Securities Act of 1933. These securities may only be resold in exempt transactions to qualified buyers. Private resales of these securities to qualified instutional buyers are also exempt from registration pursuant to Rule 144A under the Securities Act of 1933. At June 30, 2007, these securities had an aggregate value of $311,661, which represented 9.7% of net assets.

(d)  At June 30, 2007 for federal income tax purposes cost of investments was $2,162,847 and net unrealized appreciation was $1,033,597 consisting of gross unrealized appreciation of $1,078,817 and gross unrealized depreciation of $45,220.

61

Columbia Thermostat Fund

Statement of Investments (Unaudited), June 30, 2007

Number of Shares or Principal Amount (000)			Value (000)
		> Bond Funds: 65.0%
	6,761,238	Columbia Intermediate Bond Fund, Class Z	$	58,688
	3,449,983	Columbia Federal Securities Fund, Class Z		35,190
	2,788,437	Columbia Conservative High Yield Fund, Class Z		23,088
Total Bond Funds (Cost: $118,839)				116,966
		> Stock Funds: 34.8%
	1,026,125	Columbia LargeCap Enhanced Core Fund, Class Z		15,659
	833,310	Columbia Dividend Income Fund, Class Z		12,591
	205,779	Columbia Acorn International, Class Z		9,429
	287,018	Columbia Acorn Fund, Class Z		9,403
	432,063	Columbia Marsico Growth Fund, Class Z		9,367
	203,678	Columbia Acorn Select, Class Z		6,285
Total Stock Funds (Cost: $52,596)				62,734
Short-Term Obligation: 0.4%
$	642	Repurchase Agreement with Fixed Income Clearing Corp., dated 6/29/07, due 7/02/07 at 5.050%, collateralized by a U.S. Government Agency Obligation, maturing 7/18/11 market value of $660 (repurchase proceeds $642)		642
		(Cost: $642)		642
Total Investments: 100.2% (Cost: $172,077)(a)				180,342
Cash and Other Assets Less Liabilities: (0.2)%				(313	)
Total Net Assets: 100%			$	180,029

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

(a)  At June 30, 2007, for federal income tax purposes cost of investments was $172,077 and net unrealized appreciation was $8,265, consisting of gross unrealized appreciation of $10,274 and gross unrealized depreciation of $2,009.

62

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63

Columbia Acorn Family of Funds

Statements of Assets and Liabilities (Unaudited)

June 30, 2007	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	$	9,996,498	$	3,298,899		$	1,219,286	$	172,614		$	1,936,212		$	—
Affiliated investments, at cost (See Note 4)		2,646,859		102,622			3,130		—			226,635			172,077
Unaffiliated investments, at value	$	16,693,498	$	5,306,474		$	1,723,452	$	219,961		$	2,898,622		$	—
Affiliated investments, at value (See Note 4)		4,477,872		107,652			6,123		—			297,822			180,342
Cash		1,039		—	*		1,796		1			—	*		—	*
Foreign currency (cost: Columbia Acorn Fund $8,676; Columbia Acorn International $20,729; Columbia Acorn International Select $168)		8,694		20,858			—		168			—			—
Receivable for:
Investments sold		127,912		30,366			13,231		1,817			—			—
Fund shares sold		30,087		7,954			3,218		379			25,903			114
Dividends and interest		8,693		4,985			461		110			398			—	*
Foreign tax reclaims		606		1,183			—		59			—			—
Deferred Trustees' Compensation Investments		2,770		756			205		—			—			—
Expense Reimbursement due from Investment Adviser		—		—			—		—			—			50
Other assets		—		—			—		—			8			—
Total Assets		21,351,171		5,480,228			1,748,486		222,495			3,222,753			180,506
Liabilities:
Payable for:
Investments purchased		82,437		13,814			12,022		—			9,496			—
Fund shares redeemed		15,776		1,983			30,937		204			3,578			230
Management fee		11,164		3,337			1,230		166			2,020			15
Administration fee		695		174			57		7			102			6
12b-1 Service & Distribution fees		3,044		267			143		22			572			75
Reports to shareholders		1,568		350			154		36			331			65
Deferred Trustees' fees		2,770		756			205		26			183			22
Transfer agent fees		1,840		161			152		6			290			51
Trustees' fees		112		9			8		—	*		1			—	*
Audit fee		43		42			22		21			22			11
Custody fees		231		175			5		4			16			—	*
Deferred foreign capital gains tax payable		—		392			—		—			—			—
Other liabilities		213		38			13		11			—			2
Total Liabilities		119,893		21,498			44,948		503			16,611			477
Net Assets	$	21,231,278	$	5,458,730		$	1,703,538	$	221,992		$	3,206,142		$	180,029
Composition of Net Assets:
Paid in capital	$	11,951,843	$	3,203,553		$	1,134,839	$	166,910		$	2,138,388		$	165,454
Undistributed (overdistributed) net investment income (Accumulated net investment loss)		20,675		4,898			1,551		547			(15,544	)		2,903
Accumulated net realized gain		730,715		237,906			59,989		7,187			49,701			3,407
Net unrealized appreciation on:
Investments		8,528,013		2,012,605			507,159		47,347			1,033,597			8,265
Foreign capital gains tax		—		(392	)		—		—			—			—
Foreign currency translations		32		160			—		1			—			—
Net Assets	$	21,231,278	$	5,458,730		$	1,703,538	$	221,992		$	3,206,142		$	180,029
Net asset value per share – Class A (a)	$	31.94	$	45.59		$	30.37	$	30.82		$	30.35		$	12.80
(Net assets/shares)		($4,632,464/145,034)		($495,307/10,864)			($265,857/8,754)		($36,156/1,173)			($1,240,930/40,885)			($51,470/4,020)
Maximum offering price per share – Class A (b)	$	33.89	$	48.37		$	32.22	$	32.70		$	32.20		$	13.58
(Net asset value per share/front- end sales charge)		($31.94/0.9425)		($45.59/0.9425)			($30.37/0.9425)		($30.82/0.9425)			($30.35/0.9425)			($12.80/0.9425)
Net asset value and offering price per share – Class B (a)	$	30.47	$	44.69		$	29.02	$	29.74		$	29.03		$	12.84
(Net assets/shares)		($1,440,071/47,265)		($103,314/2,311)			($63,927/2,203)		($10,892/366)			($231,739/7,983)			($69,096/5,383)
Net asset value and offering price per share – Class C (a)	$	30.35	$	44.61		$	28.93	$	29.68		$	28.94		$	12.82
(Net assets/shares)		($1,450,101/47,779)		($135,340/3,035)			($57,674/1,993)		($9,778/329)			($222,201/7,679)			($25,991/2,028)
Net asset value and offering price per share – Class Z (c)	$	32.76	$	45.82		$	31.11	$	31.12		$	30.86		$	12.77
(Net assets/shares)		($13,708,642/418,519)		($4,724,769/103,107)			($1,316,080/42,302)		($165,166/5,308)			($1,511,272/48,965)			($33,472/2,622)

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

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

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

*  Rounds to less than $500.

See accompanying notes to financial statements.

64

Columbia Acorn Family of Funds

Statements of Operations (Unaudited)
For the Six Months Ended June 30, 2007

(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	$	96,782		$	55,989		$	8,785		$	1,827		$	4,355		$	—
Dividend income from affiliates (See Note 4)		17,334			2,028			—			—			—			—
Dividends from affiliated investment company shares (See Note 4)		—			—			—			—			—			3,618
Interest income		29,275			7,691			1,985			328			5,967			20
		143,391			65,708			10,770			2,155			10,322			3,638
Foreign taxes withheld		(1,937	)		(4,753	)		—	*		(123	)		(22	)		—
Total Investment Income		141,454			60,955			10,770			2,032			10,300			3,638
Expenses:
Management fee		64,166			18,550			7,160			915			10,678			92
Administration fee		3,856			931			320			37			513			35
12b-1 Service and Distribution fees:
Class A		5,431			495			328			37			1,354			68
Class B		5,328			366			241			39			839			264
Class C		6,984			583			282			41			977			134
Transfer agent fees:
Class A		1,498			158			91			13			408			46
Class B		1,069			90			58			11			203			63
Class C		688			60			30			6			116			24
Class Z		1,944			564			250			33			230			16
Custody fees		755			997			32			30			69			—	*
Trustees' fees		367			74			30			15			155			18
Registration & blue sky fees		129			82			54			40			56			32
Reports to shareholders		1,381			355			167			43			318			71
Chief compliance officer expenses (See Note 4)		244			58			23			6			32			6
Other expenses		480			137			59			31			70			25
Total expenses		94,320			23,500			9,125			1,297			16,018			894
Less custody fees paid indirectly		(69	)		(1	)		(14	)		—	*		(45	)		—	*
Less reimbursement of expenses by Investment Adviser		—			—			—			—			—			(187	)
Less reimbursement of expenses by Transfer Agent
Class A		(212	)		(16	)		(11	)		(1	)		(53	)		(4	)
Class B		(86	)		(7	)		(4	)		(1	)		(16	)		(5	)
Class C		(63	)		(6	)		(3	)		(1	)		(10	)		(2	)
Class Z		(376	)		(27	)		(48	)		(1	)		(21	)		—	*
Net Expenses		93,514			23,443			9,045			1,293			15,873			696
Net Investment Income (Loss)		47,940			37,512			1,725			739			(5,573	)		2,942
Net Realized and Unrealized Gain (Loss) on Portfolio Positions:
Net realized gain (loss) on:
Unaffiliated investments		602,100			240,610			62,278			15,823			49,991			—
Affiliated investments (See Note 4)		131,455			(20	)		—			—			—			4,235
Foreign currency transactions		(421	)		(847	)		—			(21	)		(18	)		—
Net realized gain on disposal of investments sold in error   (See Note 8)		4			—			—			—			—			—
Net realized gain		733,138			239,743			62,278			15,802			49,973			4,235
Net change in net unrealized appreciation (depreciation) on:
Unaffiliated investments		1,050,397			387,043			86,603			5,277			360,688			—
Affiliated investments (See Note 4)		339,838			5,031			—			—			—			405
Foreign currency translations		10			109			—			(2	)		69			—
Foreign capital gains tax		—			(392	)		—			—			—			—
Net change in unrealized appreciation (depreciation)		1,390,245			391,791			86,603			5,275			360,757			405
Net realized and unrealized gain		2,123,383			631,534			148,881			21,077			410,730			4,640
Net Increase in Net Assets resulting from Operations	$	2,171,323		$	669,046		$	150,606		$	21,816		$	405,157		$	7,582

*  Rounds to less than $500.

See accompanying notes to financial statements.

65

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)	2007			2006			2007			2006			2007			2006
Operations:
Net investment income (loss)	$	47,940		$	35,190		$	37,512		$	31,386		$	1,725		$	(3,110	)
Net realized gain on investments and foreign currency transactions		733,138			1,611,966			239,743			392,116			62,278			46,861
Net realized gain on affiliated investments and distributions from affiliated investment company shares		—			—			—			—			—			—
Net change in net unrealized appreciation (depreciation) on investments and foreign currency translations		1,390,245			712,218			391,791			645,701			86,603			64,360
Net change in net unrealized appreciation (depreciation) on affiliated investments		—			—			—			—			—			—
Net Increase from Operations		2,171,323			2,359,374			669,046			1,069,203			150,606			108,111
Distributions to Shareholders From:
Net investment income – Class A		—			(5,394	)		(61	)		(2,223	)		—			—
Net realized gain – Class A		(55,515	)		(313,513	)		(2,579	)		(26,545	)		(2,466	)		(5,181	)
Net investment income – Class B		—			—			—	*		(141	)		—			—
Net realized gain – Class B		(18,288	)		(114,707	)		(575	)		(8,646	)		(620	)		(1,487	)
Net investment income – Class C		—			—			—	*		(63	)		—			—
Net realized gain – Class C		(18,339	)		(109,093	)		(744	)		(8,998	)		(557	)		(1,223	)
Net investment income – Class Z		—			(48,532	)		(12,297	)		(44,617	)		—			—
Net realized gain – Class Z		(160,345	)		(916,129	)		(25,155	)		(342,510	)		(12,016	)		(25,202	)
Total Distributions to Shareholders		(252,487	)		(1,507,368	)		(41,411	)		(433,743	)		(15,659	)		(33,093	)
Share Transactions:
Subscriptions – Class A		615,959			1,078,213			175,970			176,101			51,185			113,090
Distributions reinvested – Class A		50,288			288,002			2,412			25,843			2,159			4,383
Redemptions – Class A		(513,833	)		(822,590	)		(48,303	)		(63,857	)		(53,863	)		(51,382	)
Net Increase (Decrease) – Class A		152,414			543,625			130,079			138,087			(519	)		66,091
Subscriptions – Class B		7,608			25,556			8,524			17,920			222			1,247
Distributions reinvested – Class B		16,730			104,566			526			8,016			566			1,351
Redemptions – Class B		(119,998	)		(212,371	)		(12,274	)		(20,296	)		(6,865	)		(14,036	)
Net Increase (Decrease) – Class B		(95,660	)		(82,249	)		(3,224	)		5,640			(6,077	)		(11,438	)
Subscriptions – Class C		65,011			166,508			29,598			50,734			2,005			17,895
Distributions reinvested – Class C		14,519			86,726			555			6,707			476			1,038
Redemptions – Class C		(102,057	)		(178,699	)		(9,005	)		(16,582	)		(4,411	)		(8,640	)
Net Increase (Decrease) – Class C		(22,527	)		74,535			21,148			40,859			(1,930	)		10,293
Subscriptions – Class Z		1,051,261			1,754,910			497,235			707,961			117,188			371,430
Distributions reinvested – Class Z		137,592			824,254			26,711			279,893			10,953			22,838
Redemptions – Class Z		(855,764	)		(1,413,279	)		(184,352	)		(357,229	)		(131,252	)		(175,498	)
Net Increase (Decrease) – Class Z		333,089			1,165,885			339,594			630,625			(3,111	)		218,770
Net Increase (Decrease) from Share Transactions		367,316			1,701,796			487,597			815,211			(11,637	)		283,716
Redemption Fees		—			—			103			147			—			—
Total Increase (Decrease) in Net Assets		2,286,152			2,553,802			1,115,335			1,450,818			123,310			358,734
Net Assets:
Beginning of period		18,945,126			16,391,324			4,343,395			2,892,577			1,580,228			1,221,494
End of period	$	21,231,278		$	18,945,126		$	5,458,730		$	4,343,395		$	1,703,538		$	1,580,228
Undistributed (Overdistributed) Net Investment Income or (Accumulated Net Investment Loss)	$	20,675		$	(27,265	)	$	4,898		$	(20,256	)	$	1,551		$	(174	)

*  Rounds to less than $500.

See accompanying notes to financial statements.

66

	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)	2007			2006			2007			2006			2007			2006
Operations:
Net investment income (loss)	$	739		$	361		$	(5,573	)	$	(11,032	)	$	2,942		$	6,358
Net realized gain on investments and foreign currency transactions		15,802			18,110			49,973			71,803			—			—
Net realized gain on affiliated investments and distributions from affiliated investment company shares		—			—			—			—			4,235			11,669
Net change in net unrealized appreciation (depreciation) on investments and foreign currency translations		5,275			20,770			360,757			287,875			—			—
Net change in net unrealized appreciation (depreciation) on affiliated investments		—			—			—			—			405			836
Net Increase from Operations		21,816			39,241			405,157			348,646			7,582			18,863
Distributions to Shareholders From:
Net investment income – Class A		(86	)		(2	)		—			(788	)		(125	)		(2,086	)
Net realized gain – Class A		—			—			(7,498	)		(20,503	)		(1,184	)		(3,300	)
Net investment income – Class B		—			—			—			—			—			(2,114	)
Net realized gain – Class B		—			—			(1,510	)		(4,991	)		(1,571	)		(3,980	)
Net investment income – Class C		—			—	*		—			—			—			(753	)
Net realized gain – Class C		—			—			(1,407	)		(3,972	)		(596	)		(1,496	)
Net investment income – Class Z		(782	)		(196	)		—			(1,614	)		(163	)		(1,223	)
Net realized gain – Class Z		—			—			(8,765	)		(19,241	)		(760	)		(1,585	)
Total Distributions to Shareholders		(868	)		(198	)		(19,180	)		(51,109	)		(4,399	)		(16,537	)
Share Transactions:
Subscriptions – Class A		13,035			10,850			233,175			210,532			3,216			6,298
Distributions reinvested – Class A		78			2			6,845			19,667			1,205			4,887
Redemptions – Class A		(2,741	)		(3,070	)		(97,602	)		(158,467	)		(11,969	)		(25,185	)
Net Increase (Decrease) – Class A		10,372			7,782			142,418			71,732			(7,548	)		(14,000	)
Subscriptions – Class B		1,382			2,223			2,301			4,782			1,993			3,578
Distributions reinvested – Class B		—			—			1,343			4,452			1,445			5,496
Redemptions – Class B		(1,392	)		(1,437	)		(18,505	)		(31,688	)		(7,964	)		(16,105	)
Net Increase (Decrease) – Class B		(10	)		786			(14,861	)		(22,454	)		(4,526	)		(7,031	)
Subscriptions – Class C		2,439			2,333			34,501			20,817			1,995			4,114
Distributions reinvested – Class C		—			—	*		1,110			3,230			529			1,960
Redemptions – Class C		(617	)		(924	)		(14,166	)		(22,947	)		(4,352	)		(7,323	)
Net Increase (Decrease) – Class C		1,822			1,409			21,445			1,100			(1,828	)		(1,249	)
Subscriptions – Class Z		30,453			34,878			499,307			258,516			3,072			5,698
Distributions reinvested – Class Z		341			99			6,448			14,293			855			2,633
Redemptions – Class Z		(10,851	)		(10,107	)		(72,303	)		(170,328	)		(1,708	)		(3,204	)
Net Increase (Decrease) – Class Z		19,943			24,870			433,452			102,481			2,219			5,127
Net Increase (Decrease) from Share Transactions		32,127			34,847			582,454			152,859			(11,683	)		(17,153	)
Redemption Fees		19			9			—			—			—			—
Total Increase (Decrease) in Net Assets		53,094			73,899			968,431			450,396			(8,500	)		(14,827	)
Net Assets:
Beginning of period		168,898			94,999			2,237,711			1,787,315			188,529			203,356
End of period	$	221,992		$	168,898		$	3,206,142		$	2,237,711		$	180,029		$	188,529
Undistributed (Overdistributed) Net Investment Income or (Accumulated Net Investment Loss)	$	547		$	676		$	(15,544	)	$	(9,971	)	$	2,903		$	249

67

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)	2007			2006			2007			2006			2007			2006
Subscriptions – Class A		20,066			37,015			4,120			4,588			1,756			4,113
Shares issued in reinvestment and capital gains – Class A		1,551			9,911			53			673			70			156
Less shares redeemed – Class A		(16,739	)		(28,264	)		(1,131	)		(1,723	)		(1,835	)		(1,877	)
Net Increase (Decrease) – Class A		4,878			18,662			3,042			3,538			(9	)		2,392
Subscriptions – Class B		260			909			203			482			8			47
Shares issued in reinvestment and capital gains – Class B		540			3,757			12			212			19			50
Less shares redeemed – Class B		(4,079	)		(7,576	)		(294	)		(553	)		(245	)		(533	)
Net Increase (Decrease) – Class B		(3,279	)		(2,910	)		(79	)		141			(218	)		(436	)
Subscriptions – Class C		2,223			5,931			709			1,356			72			678
Shares issued in reinvestment and capital gains – Class C		471			3,123			13			178			16			39
Less shares redeemed – Class C		(3,486	)		(6,396	)		(214	)		(455	)		(158	)		(328	)
Net Increase (Decrease) – Class C		(792	)		2,658			508			1,079			(70	)		389
Subscriptions – Class Z		33,477			58,774			11,650			18,601			3,909			13,228
Shares issued in reinvestment and capital gains – Class Z		4,138			27,709			588			7,251			345			796
Less shares redeemed – Class Z		(27,249	)		(47,499	)		(4,294	)		(9,331	)		(4,324	)		(6,302	)
Net Increase (Decrease) – Class Z		10,366			38,984			7,944			16,521			(70	)		7,722
Net Increase (Decrease) in Shares of Beneficial Interest		11,173			57,394			11,415			21,279			(367	)		10,067

*  Rounds to less than 500 shares.

See accompanying notes to financial statements.

68

	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)	2007			2006			2007			2006			2007			2006
Subscriptions – Class A		447			446			8,142			8,645			249			492
Shares issued in reinvestment and capital gains – Class A		3			—	*		222			777			93			390
Less shares redeemed – Class A		(94	)		(131	)		(3,412	)		(6,607	)		(931	)		(1,960	)
Net Increase (Decrease) – Class A		356			315			4,952			2,815			(589	)		(1,078	)
Subscriptions – Class B		49			97			85			207			154			279
Shares issued in reinvestment and capital gains – Class B		—	*		—	*		45			183			112			437
Less shares redeemed – Class B		(49	)		(64	)		(675	)		(1,373	)		(616	)		(1,253	)
Net Increase (Decrease) – Class B		—			33			(545	)		(983	)		(350	)		(537	)
Subscriptions – Class C		87			100			1,252			898			155			322
Shares issued in reinvestment and capital gains – Class C		—			—	*		38			133			40			156
Less shares redeemed – Class C		(22	)		(42	)		(518	)		(1,002	)		(336	)		(572	)
Net Increase (Decrease) – Class C		65			58			772			29			(141	)		(94	)
Subscriptions – Class Z		1,040			1,448			17,043			10,565			239			442
Shares issued in reinvestment and capital gains – Class Z		11			5			206			559			66			210
Less shares redeemed – Class Z		(371	)		(427	)		(2,490	)		(7,111	)		(131	)		(248	)
Net Increase (Decrease) – Class Z		680			1,026			14,759			4,013			174			404
Net Increase (Decrease) in Shares of Beneficial Interest		1,101			1,432			19,938			5,874			(906	)		(1,305	)

69

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	2007			2006			2005			2004			2003			2002
Net Asset Value, Beginning of Period	$	29.02		$	27.57		$	25.93		$	22.20		$	15.34		$	17.80
Income from Investment Operations
Net investment income (loss) (a)		0.06			0.05			0.07			(0.05	)		(0.07	)		(0.07	)
Net realized and unrealized gain (loss)		3.25			3.82			3.20			4.69			6.95			(2.39	)
Total from Investment Operations		3.31			3.87			3.27			4.64			6.88			(2.46	)
Less Distributions Declared to Shareholders
From net investment income		—			(0.04	)		(0.07	)		—			—			—
From net realized gains		(0.39	)		(2.38	)		(1.56	)		(0.91	)		(0.02	)		—
Total Distributions Declared to Shareholders		(0.39	)		(2.42	)		(1.63	)		(0.91	)		(0.02	)		—
Net Asset Value, End of Period	$	31.94		$	29.02		$	27.57		$	25.93		$	22.20		$	15.34
Total Return (b)		11.37	%(c)(d)		14.13	%(c)		12.76	%(c)		21.05	%(c)		44.85	%		(13.82	)%
Ratios to Average Net Assets/Supplemental Data
Net expenses (e)		1.02	%(f)		1.02	%		1.03	%		1.20	%		1.33	%		1.42	%
Net investment income (loss) (e)		0.39	%(f)		0.17	%		0.28	%		(0.21	)%		(0.36	)%		(0.45	)%
Waiver/reimbursement		0.01	%(f)		0.02	%		0.02	%		0.02	%		—			—
Portfolio turnover rate		10	%(d)		22	%		16	%		20	%		10	%		13	%
Net assets at end of period (000's)	$	4,632,464		$	4,067,868		$	3,349,461		$	2,669,936		$	1,982,260		$	724,121

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

(d)  Not annualized.

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

(f)  Annualized.

Class B Shares	(Unaudited) Six months ended June 30,			Year ended December 31,
Selected data for a share outstanding throughout each period	2007			2006			2005			2004			2003			2002
Net Asset Value, Beginning of Period	$	27.78		$	26.61		$	25.19		$	21.75		$	15.13		$	17.67
Income from Investment Operations
Net investment loss (a)		(0.03	)		(0.13	)		(0.11	)		(0.22	)		(0.18	)		(0.17	)
Net realized and unrealized gain (loss)		3.11			3.68			3.09			4.57			6.82			(2.37	)
Total from Investment Operations		3.08			3.55			2.98			4.35			6.64			(2.54	)
Less Distributions Declared to Shareholders
From net realized gains		(0.39	)		(2.38	)		(1.56	)		(0.91	)		(0.02	)		—
Total Distributions Declared to Shareholders		(0.39	)		(2.38	)		(1.56	)		(0.91	)		(0.02	)		—
Net Asset Value, End of Period	$	30.47		$	27.78		$	26.61		$	25.19		$	21.75		$	15.13
Total Return (b)		11.05	%(c)(d)		13.43	%(c)		11.98	%(c)		20.15	%(c)		43.89	%		(14.37	)%
Ratios to Average Net Assets/Supplemental Data
Net expenses (e)		1.60	%(f)		1.66	%		1.72	%		1.95	%		1.98	%		2.07	%
Net investment loss (e)		(0.19	)%(f)		(0.48	)%		(0.42	)%		(0.96	)%		(1.01	)%		(1.10	)%
Waiver/reimbursement		0.01	%(f)		0.02	%		0.02	%		0.02	%		—			—
Portfolio turnover rate		10	%(d)		22	%		16	%		20	%		10	%		13	%
Net assets at end of period (000's)	$	1,440,071		$	1,404,165		$	1,422,580		$	1,399,135		$	1,221,931		$	618,727

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

(d)  Not annualized.

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

(f)  Annualized.

Class C Shares	(Unaudited) Six months ended June 30,			Year ended December 31,
Selected data for a share outstanding throughout each period	2007			2006			2005			2004			2003			2002
Net Asset Value, Beginning of Period	$	27.70		$	26.58		$	25.18		$	21.75		$	15.12		$	17.66
Income from Investment Operations
Net investment loss (a)		(0.06	)		(0.17	)		(0.13	)		(0.22	)		(0.18	)		(0.17	)
Net realized and unrealized gain (loss)		3.10			3.67			3.09			4.56			6.83			(2.37	)
Total from Investment Operations		3.04			3.50			2.96			4.34			6.65			(2.54	)
Less Distributions Declared to Shareholders
From net realized gains		(0.39	)		(2.38	)		(1.56	)		(0.91	)		(0.02	)		—
Total Distributions Declared to Shareholders		(0.39	)		(2.38	)		(1.56	)		(0.91	)		(0.02	)		—
Net Asset Value, End of Period	$	30.35		$	27.70		$	26.58		$	25.18		$	21.75		$	15.12
Total Return (b)		10.94	%(c)(d)		13.25	%(c)		11.90	%(c)		20.11	%(c)		43.99	%		(14.38	)%
Ratios to Average Net Assets/Supplemental Data
Net expenses (e)		1.80	%(f)		1.80	%		1.82	%		1.95	%		1.98	%		2.07	%
Net investment loss (e)		(0.39	)%(f)		(0.61	)%		(0.51	)%		(0.96	)%		(1.01	)%		(1.10	)%
Waiver/reimbursement		0.01	%(f)		0.02	%		0.02	%		0.02	%		—			—
Portfolio turnover rate		10	%(d)		22	%		16	%		20	%		10	%		13	%
Net assets at end of period (000's)	$	1,450,101		$	1,345,520		$	1,220,339		$	1,083,006		$	900,016		$	376,024

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

(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.

70

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	2007			2006			2005			2004			2003			2002
Net Asset Value, Beginning of Period	$	40.07		$	33.20		$	28.75		$	22.45		$	15.32		$	18.35
Income from Investment Operations
Net investment income (a)		0.29			0.23			0.22			0.14			0.10			0.05
Net realized and unrealized gain (loss)		5.48			10.87			5.84			6.31			7.08			(3.07	)
Total from Investment Operations		5.77			11.10			6.06			6.45			7.18			(3.02	)
Less Distributions Declared to Shareholders
From net investment income		—	(b)		(0.32	)		(0.53	)		(0.15	)		(0.05	)		(0.01	)
From net realized gains		(0.25	)		(3.91	)		(1.08	)		—			—			—
Total Distributions Declared to Shareholders		(0.25	)		(4.23	)		(1.61	)		(0.15	)		(0.05	)		(0.01	)
Net Asset Value, End of Period	$	45.59		$	40.07		$	33.20		$	28.75		$	22.45		$	15.32
Total Return (c)		14.41	%(d)(e)		34.16	%(d)		21.42	%(d)		28.91	%(d)		46.94	%		(16.46	)%
Ratios to Average Net Assets/Supplemental Data
Net expenses (f)		1.19	%(g)		1.24	%		1.30	%		1.48	%		1.59	%		1.56	%
Net investment income (f)		1.37	%(g)		0.61	%		0.72	%		0.61	%		0.57	%		0.30	%
Waiver/reimbursement		0.01	%(g)		0.01	%		0.02	%		0.02	%		—			—
Portfolio turnover rate		16	%(e)		31	%		27	%		40	%		40	%		52	%
Net assets at end of period (000's)	$	495,307		$	313,401		$	142,204		$	70,582		$	52,872		$	33,806

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

(b)  Rounds to less than ($0.01).

(c)  Total return at net asset value assuming all distributions reinvested and no initial sales charge or contingent deferred sales charge.

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

(e)  Not annualized.

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

(g)  Annualized.

Class B Shares	(Unaudited) Six months ended June 30,			Year ended December 31,
Selected data for a share outstanding throughout each period	2007			2006			2005			2004			2003			2002
Net Asset Value, Beginning of Period	$	39.39		$	32.71		$	28.18		$	22.07		$	15.11		$	18.22
Income from Investment Operations
Net investment income (loss) (a)		0.14			(0.00	)(b)		0.02			(0.04	)		(0.02	)		(0.06	)
Net realized and unrealized gain (loss)		5.41			10.66			5.73			6.19			6.98			(3.05	)
Total from Investment Operations		5.55			10.66			5.75			6.15			6.96			(3.11	)
Less Distributions Declared to Shareholders
From net investment income		—			(0.07	)		(0.14	)		(0.04	)		—			—
From net realized gains		(0.25	)		(3.91	)		(1.08	)		—			—			—
Total Distributions Declared to Shareholders		(0.25	)		(3.98	)		(1.22	)		(0.04	)		—			—
Net Asset Value, End of Period	$	44.69		$	39.39		$	32.71		$	28.18		$	22.07		$	15.11
Total Return (c)		14.09	%(d)(e)		33.26	%(d)		20.57	%(d)		27.91	%(d)		46.06	%		(17.07	)%
Ratios to Average Net Assets/Supplemental Data
Net expenses (f)		1.79	%(g)		1.89	%		2.01	%		2.27	%		2.24	%		2.21	%
Net investment income (loss) (f)		0.69	%(g)		(0.01	)%		0.08	%		(0.18	)%		(0.10	)%		(0.35	)%
Waiver/reimbursement		0.01	%(g)		0.02	%		0.02	%		0.02	%		—			—
Portfolio turnover rate		16	%(e)		31	%		27	%		40	%		40	%		52	%
Net assets at end of period (000's)	$	103,314		$	94,165		$	73,572		$	54,752		$	39,800		$	22,560

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

(b)  Rounds to less than $(0.01).

(c)  Total return at net asset value assuming all distributions reinvested and no initial sales charge or contingent deferred sales charge.

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

(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.

Class C Shares	(Unaudited) Six months ended June 30,			Year ended December 31,
Selected data for a share outstanding throughout each period	2007			2006			2005			2004			2003			2002
Net Asset Value, Beginning of Period	$	39.35		$	32.68		$	28.19		$	22.06		$	15.11		$	18.21
Income from Investment Operations
Net investment income (loss) (a)		0.12			(0.05	)		(0.00	)(b)		(0.03	)		(0.01	)		(0.06	)
Net realized and unrealized gain (loss)		5.39			10.66			5.71			6.20			6.96			(3.04	)
Total from Investment Operations		5.51			10.61			5.71			6.17			6.95			(3.10	)
Less Distributions Declared to Shareholders
From net investment income		—			(0.03	)		(0.14	)		(0.04	)		—			—
From net realized gains		(0.25	)		(3.91	)		(1.08	)		—			—			—
Total Distributions Declared to Shareholders		(0.25	)		(3.94	)		(1.22	)		(0.04	)		—			—
Net Asset Value, End of Period	$	44.61		$	39.35		$	32.68		$	28.19		$	22.06		$	15.11
Total Return (c)		14.00	%(d)(e)		33.14	%(d)		20.45	%(d)		28.01	%(d)		46.00	%		(17.02	)%
Ratios to Average Net Assets/Supplemental Data
Net expenses (f)		1.96	%(g)		2.01	%		2.09	%		2.24	%		2.24	%		2.21	%
Net investment income (loss) (f)		0.57	%(g)		(0.14	)%		(0.01	)%		(0.15	)%		(0.06	)%		(0.35	)%
Waiver/reimbursement		0.01	%(g)		0.01	%		0.02	%		0.02	%		—			—
Portfolio turnover rate		16	%(e)		31	%		27	%		40	%		40	%		52	%
Net assets at end of period (000's)	$	135,340		$	99,425		$	47,325		$	30,547		$	22,990		$	14,575

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

(b)  Rounds to less than $(0.01).

(c)  Total return at net asset value assuming all distributions reinvested and no initial sales charge or contingent deferred sales charge.

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

(e)  Not annualized.

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

(g)  Annualized.

71

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	2007			2006			2005			2004			2003			2002
Net Asset Value, Beginning of Period	$	28.02		$	26.52		$	24.77		$	20.74		$	14.18		$	17.50
Income from Investment Operations
Net investment income (loss) (a)		0.01			(0.10	)		(0.01	)		(0.24	)		(0.22	)		(0.19	)
Net realized and unrealized gain (loss)		2.62			2.21			3.13			4.41			6.78			(3.13	)
Total from Investment Operations		2.63			2.11			3.12			4.17			6.56			(3.32	)
Less Distributions Declared to Shareholders
From net realized gains		(0.28	)		(0.61	)		(1.37	)		(0.14	)		—			—
Net Asset Value, End of Period	$	30.37		$	28.02		$	26.52		$	24.77		$	20.74		$	14.18
Total Return (b)		9.36	%(c)(d)		7.95	%(c)		12.68	%(c)		20.12	%(c)		46.26	%		(18.97	)%
Ratios to Average Net Assets/Supplemental Data
Net expenses (e)		1.25	%(f)		1.26	%		1.31	%		1.51	%		1.65	%		1.74	%
Net investment income (loss) (e)		0.05	%(f)		(0.35	)%		(0.02	)%		(1.08	)%		(1.26	)%		(1.21	)%
Waiver/reimbursement		0.01	%(f)		0.01	%		0.01	%		0.02	%		—			—
Portfolio turnover rate		9	%(d)		13	%		13	%		18	%		7	%		31	%
Net assets at end of period (000's)	$	265,857		$	245,552		$	168,922		$	112,509		$	89,650		$	32,422

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

(d)  Not annualized.

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

(f)  Annualized.

Class B Shares	(Unaudited) Six months ended June 30,			Year ended December 31,
Selected data for a share outstanding throughout each period	2007			2006			2005			2004			2003			2002
Net Asset Value, Beginning of Period	$	26.87		$	25.61		$	24.14		$	20.36		$	14.01		$	17.40
Income from Investment Operations
Net investment loss (a)		(0.08	)		(0.27	)		(0.18	)		(0.39	)		(0.32	)		(0.29	)
Net realized and unrealized gain (loss)		2.51			2.14			3.02			4.31			6.67			(3.10	)
Total from Investment Operations		2.43			1.87			2.84			3.92			6.35			(3.39	)
Less Distributions Declared to Shareholders
From net realized gains		(0.28	)		(0.61	)		(1.37	)		(0.14	)		—			—
Net Asset Value, End of Period	$	29.02		$	26.87		$	25.61		$	24.14		$	20.36		$	14.01
Total Return (b)		9.02	%(c)(d)		7.29	%(c)		11.84	%(c)		19.26	%(c)		45.32	%		(19.48	)%
Ratios to Average Net Assets/Supplemental Data
Net expenses (e)		1.86	%(f)		1.93	%		2.00	%		2.23	%		2.30	%		2.39	%
Net investment loss (e)		(0.57	)%(f)		(1.01	)%		(0.72	)%		(1.80	)%		(1.91	)%		(1.86	)%
Waiver/reimbursement		0.01	%(f)		0.02	%		0.01	%		0.02	%		—			—
Portfolio turnover rate		9	%(d)		13	%		13	%		18	%		7	%		31	%
Net assets at end of period (000's)	$	63,927		$	65,040		$	73,168		$	72,643		$	66,175		$	37,478

(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 contingentdeferred sales charge.

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

(d)  Not annualized.

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

(f)  Annualized.

Class C Shares	(Unaudited) Six months ended June 30,			Year ended December 31,
Selected data for a share outstanding throughout each period	2007			2006			2005			2004			2003			2002
Net Asset Value, Beginning of Period	$	26.81		$	25.59		$	24.14		$	20.36		$	14.01		$	17.40
Income from Investment Operations
Net investment loss (a)		(0.10	)		(0.30	)		(0.20	)		(0.39	)		(0.32	)		(0.29	)
Net realized and unrealized gain (loss)		2.50			2.13			3.02			4.31			6.67			(3.10	)
Total from Investment Operations		2.40			1.83			2.82			3.92			6.35			(3.39	)
Less Distributions Declared to Shareholders
From net realized gains		(0.28	)		(0.61	)		(1.37	)		(0.14	)		—			—
Net Asset Value, End of Period	$	28.93		$	26.81		$	25.59		$	24.14		$	20.36		$	14.01
Total Return (b)		8.93	%(c)(d)		7.14	%(c)		11.76	%(c)		19.26	%(c)		45.32	%		(19.48	)%
Ratios to Average Net Assets/Supplemental Data
Net expenses (e)		2.04	%(f)		2.05	%		2.10	%		2.23	%		2.30	%		2.39	%
Net investment loss (e)		(0.75	)%(f)		(1.14	)%		(0.81	)%		(1.80	)%		(1.91	)%		(1.86	)%
Waiver/reimbursement		0.01	%(f)		0.01	%		0.01	%		0.02	%		—			—
Portfolio turnover rate		9	%(d)		13	%		13	%		18	%		7	%		31	%
Net assets at end of period (000's)	$	57,674		$	55,306		$	42,844		$	39,643		$	35,662		$	18,313

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

(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.

72

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	2007			2006			2005			2004			2003			2002
Net Asset Value, Beginning of Period	$	27.68		$	20.36		$	17.85		$	14.45		$	10.24		$	12.07
Income from Investment Operations
Net investment income (loss) (a)		0.09			0.03			0.06			(0.00	)(b)		0.03			(0.01	)
Net realized and unrealized gain (loss)		3.13			7.29			2.69			3.43			4.18			(1.82	)
Total from Investment Operations		3.22			7.32			2.75			3.43			4.21			(1.83	)
Less Distributions Declared to Shareholders
From net investment income		(0.08	)		—			(0.24	)		(0.03	)		—			—
Net Asset Value, End of Period	$	30.82		$	27.68		$	20.36		$	17.85		$	14.45		$	10.24
Total Return (c)(d)		11.62	%(e)		35.97	%		15.60	%		23.76	%		41.11	%		(15.16	)%
Ratios to Average Net Assets/Supplemental Data
Net expenses (f)		1.48	%(g)		1.58	%		1.70	%		1.75	%		1.80	%		1.80	%
Net investment income (loss) (f)		0.63	%(g)		0.11	%		0.34	%		(0.03	)%		0.24	%		(0.09	)%
Waiver/reimbursement		0.01	%(g)		0.02	%		0.10	%		0.37	%		0.44	%		0.33	%
Portfolio turnover rate		31	%(e)		47	%		39	%		73	%		69	%		102	%
Net assets at end of period (000's)	$	36,156		$	22,599		$	10,219		$	4,357		$	2,557		$	2,612

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

(b)  Rounds to less than $(0.01).

(c)  Total return at net asset value assuming all distributions reinvested and no initial sales charge or contingent deferred sales charge.

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

(e)  Not annualized.

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

(g)  Annualized.

Class B Shares	(Unaudited) Six months ended June 30,			Year ended December 31,
Selected data for a share outstanding throughout each period	2007			2006			2005			2004			2003			2002
Net Asset Value, Beginning of Period	$	26.73		$	19.80		$	17.36		$	14.12		$	10.08		$	11.96
Income from Investment Operations
Net investment loss (a)		(0.00	)(b)		(0.12	)		(0.03	)		(0.10	)		(0.06	)		(0.08	)
Net realized and unrealized gain (loss)		3.01			7.05			2.61			3.34			4.10			(1.80	)
Total from Investment Operations		3.01			6.93			2.58			3.24			4.04			(1.88	)
Less Distributions Declared to Shareholders
From net investment income		—			—			(0.14	)		—			—			—
Net Asset Value, End of Period	$	29.74		$	26.73		$	19.80		$	17.36		$	14.12		$	10.08
Total Return (c)(d)		11.26	%(e)		35.00	%		14.97	%		22.95	%		40.08	%		(15.72	)%
Ratios to Average Net Assets/Supplemental Data
Net expenses (f)		2.10	%(g)		2.25	%		2.30	%		2.38	%		2.45	%		2.45	%
Net investment loss (f)		(0.03	)%(g)		(0.53	)%		(0.16	)%		(0.66	)%		(0.52	)%		(0.74	)%
Waiver/reimbursement		0.02	%(g)		0.04	%		0.28	%		0.58	%		0.44	%		0.33	%
Portfolio turnover rate		31	%(e)		47	%		39	%		73	%		69	%		102	%
Net assets at end of period (000's)	$	10,892		$	9,787		$	6,594		$	5,097		$	3,162		$	1,835

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

(b)  Rounds to less than $(0.01).

(c)  Total return at net asset value assuming all distributions reinvested and no initial sales charge or contingent deferred sales charge.

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

(e)  Not annualized.

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

(g)  Annualized.

Class C Shares	(Unaudited) Six months ended June 30,			Year ended December 31,
Selected data for a share outstanding throughout each period	2007			2006			2005			2004			2003			2002
Net Asset Value, Beginning of Period	$	26.70		$	19.80		$	17.38		$	14.14		$	10.09		$	11.97
Income from Investment Operations
Net investment loss (a)		(0.03	)		(0.15	)		(0.05	)		(0.11	)		(0.05	)		(0.08	)
Net realized and unrealized gain (loss)		3.01			7.05			2.60			3.35			4.10			(1.80	)
Total from Investment Operations		2.98			6.90			2.55			3.24			4.05			(1.88	)
Less Distributions Declared to Shareholders
From net investment income		—			—			(0.13	)		—			—			—
Net Asset Value, End of Period	$	29.68		$	26.70		$	19.80		$	17.38		$	14.14		$	10.09
Total Return (b)(c)		11.16	%(d)		34.85	%		14.77	%		22.91	%		40.14	%		(15.71	)%
Ratios to Average Net Assets/Supplemental Data
Net expenses (e)		2.27	%(f)		2.38	%		2.45	%		2.45	%		2.45	%		2.45	%
Net investment loss (e)		(0.18	)%(f)		(0.67	)%		(0.30	)%		(0.73	)%		(0.41	)%		(0.74	)%
Waiver/reimbursement		0.01	%(f)		0.02	%		0.17	%		0.35	%		0.44	%		0.33	%
Portfolio turnover rate		31	%(d)		47	%		39	%		73	%		69	%		102	%
Net assets at end of period (000's)	$	9,778		$	7,060		$	4,083		$	2,543		$	3,691		$	2,915

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

(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.

73

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	2007			2006			2005			2004			2003			2002
Net Asset Value, Beginning of Period	$	26.18		$	22.47		$	20.83		$	18.01		$	13.93		$	15.17
Income from Investment Operations
Net investment loss (a)		(0.06	)		(0.13	)		(0.09	)		(0.16	)		(0.20	)		(0.16	)
Net realized and unrealized gain (loss)		4.42			4.45			2.32			3.42			4.37			(1.08	)
Total from Investment Operations		4.36			4.32			2.23			3.26			4.17			(1.24	)
Less Distributions Declared to Shareholders
From net investment income		—			(0.02	)		—			—			—			—
From net realized gains		(0.19	)		(0.59	)		(0.59	)		(0.44	)		(0.09	)		—
Total Distributions Declared to Shareholders		(0.19	)		(0.61	)		(0.59	)		(0.44	)		(0.09	)		—
Net Asset Value, End of Period	$	30.35		$	26.18		$	22.47		$	20.83		$	18.01		$	13.93
Total Return (b)		16.64	%(c)(d)		19.32	%(c)		10.78	%(c)		18.16	%(c)		29.95	%		(8.17	)%(c)
Ratios to Average Net Assets/Supplemental Data
Net expenses (e)		1.20	%(f)		1.24	%		1.26	%		1.47	%		1.63	%		1.70	%
Net investment loss (e)		(0.44	)%(f)		(0.54	)%		(0.42	)%		(0.86	)%		(1.15	)%		(1.11	)%
Waiver/reimbursement		0.01	%(f)		0.03	%		0.03	%		0.02	%		—			0.10	%
Portfolio turnover rate		7	%(d)		21	%		19	%		34	%		16	%		40	%
Net assets at end of period (000's)	$	1,240,930		$	940,857		$	744,178		$	515,842		$	264,679		$	31,742

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

(d)  Not annualized.

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

(f)  Annualized.

Class B Shares	(Unaudited) Six months ended June 30,			Year ended December 31,
Selected data for a share outstanding throughout each period	2007			2006			2005			2004			2003			2002
Net Asset Value, Beginning of Period	$	25.13		$	21.71		$	20.23		$	17.64		$	13.73		$	15.05
Income from Investment Operations
Net investment loss (a)		(0.14	)		(0.28	)		(0.23	)		(0.31	)		(0.29	)		(0.25	)
Net realized and unrealized gain (loss)		4.23			4.29			2.24			3.34			4.29			(1.07	)
Total from Investment Operations		4.09			4.01			2.01			3.03			4.00			(1.32	)
Less Distributions Declared to Shareholders
From net realized gains		(0.19	)		(0.59	)		(0.53	)		(0.44	)		(0.09	)		—
Net Asset Value, End of Period	$	29.03		$	25.13		$	21.71		$	20.23		$	17.64		$	13.73
Total Return (b)		16.26	%(c)(d)		18.54	%(c)		10.01	%(c)		17.24	%(c)		29.14	%		(8.77	)%(c)
Ratios to Average Net Assets/Supplemental Data
Net expenses (e)		1.80	%(f)		1.91	%		1.99	%		2.26	%		2.28	%		2.35	%
Net investment loss (e)		(1.05	)%(f)		(1.21	)%		(1.15	)%		(1.65	)%		(1.80	)%		(1.76	)%
Waiver/reimbursement		0.01	%(f)		0.03	%		0.03	%		0.02	%		—			0.10	%
Portfolio turnover rate		7	%(d)		21	%		19	%		34	%		16	%		40	%
Net assets at end of period (000's)	$	231,739		$	214,260		$	206,441		$	185,545		$	118,064		$	33,106

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

(d)  Not annualized.

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

(f)  Annualized.

Class C Shares	(Unaudited) Six months ended June 30,			Year ended December 31,
Selected data for a share outstanding throughout each period	2007			2006			2005			2004			2003			2002
Net Asset Value, Beginning of Period	$	25.07		$	21.69		$	20.23		$	17.64		$	13.73		$	15.05
Income from Investment Operations
Net investment loss (a)		(0.17	)		(0.31	)		(0.25	)		(0.30	)		(0.30	)		(0.25	)
Net realized and unrealized gain (loss)		4.23			4.28			2.24			3.33			4.30			(1.07	)
Total from Investment Operations		4.06			3.97			1.99			3.03			4.00			(1.32	)
Less Distributions Declared to Shareholders
From net realized gains		(0.19	)		(0.59	)		(0.53	)		(0.44	)		(0.09	)		—
Net Asset Value, End of Period	$	28.94		$	25.07		$	21.69		$	20.23		$	17.64		$	13.73
Total Return (b)		16.18	%(c)(d)		18.37	%(c)		9.91	%(c)		17.24	%(c)		29.14	%		(8.77	)%(c)
Ratios to Average Net Assets/Supplemental Data
Net expenses (e)		1.99	%(f)		2.04	%		2.08	%		2.25	%		2.28	%		2.35	%
Net investment loss (e)		(1.23	)%(f)		(1.34	)%		(1.24	)%		(1.64	)%		(1.80	)%		(1.76	)%
Waiver/reimbursement		0.01	%(f)		0.03	%		0.03	%		0.02	%		—			0.10	%
Portfolio turnover rate		7	%(d)		21	%		19	%		34	%		16	%		40	%
Net assets at end of period (000's)	$	222,201		$	173,152		$	149,160		$	110,435		$	64,212		$	10,919

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

(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.

74

Columbia Thermostat Fund

Class A Shares	(Unaudited) Six months ended June 30,			Year ended December 31,									Inception March 3, 2003 through December 31,
Selected data for a share outstanding throughout each period	2007			2006			2005			2004			2003
Net Asset Value, Beginning of Period	$	12.59		$	12.49		$	13.11		$	12.30		$	10.10
Income from Investment Operations
Net investment income (a)		0.22			0.45			0.39			0.28			0.18
Net realized and unrealized gain		0.32			0.84			0.29			0.81			2.15
Total from Investment Operations		0.54			1.29			0.68			1.09			2.33
Less Distributions Declared to Shareholders
From net investment income		(0.03	)		(0.47	)		(0.39	)		(0.25	)		(0.13	)
From net realized gains		(0.30	)		(0.72	)		(0.91	)		(0.03	)		(0.00	)(b)
Total Distributions Declared to Shareholders		(0.33	)		(1.19	)		(1.30	)		(0.28	)		(0.13	)
Net Asset Value, End of Period	$	12.80		$	12.59		$	12.49		$	13.11		$	12.30
Total Return (c)(d)		4.25	%(e)		10.56	%		5.25	%		8.92	%		23.10	%(e)
Ratios to Average Net Assets/Supplemental Data
Net expenses (f)(g)		0.50	%(h)		0.50	%		0.50	%		0.50	%		0.57	%(h)
Net investment income (g)		3.44	%(h)		3.53	%		2.97	%		2.23	%		1.86	%(h)
Waiver/reimbursement		0.22	%(h)		0.20	%		0.15	%		0.33	%		0.66	%(h)
Portfolio turnover rate		39	%(e)		66	%		96	%		67	%		61	%
Net assets at end of period (000's)	$	51,470		$	58,013		$	71,034		$	77,092		$	42,271

(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).

(c)  Total return at net asset value assuming all distributions reinvested and no initial sales charge or contingent deferred sales charge.

(d)  Had the Investment Adviser and/or Transfer Agent not 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,									Inception March 3, 2003 through December 31,
Selected data for a share outstanding throughout each period	2007			2006			2005			2004			2003
Net Asset Value, Beginning of Period	$	12.62		$	12.51		$	13.14		$	12.32		$	10.10
Income from Investment Operations
Net investment income (a)		0.19			0.38			0.31			0.19			0.10
Net realized and unrealized gain		0.33			0.84			0.28			0.83			2.16
Total from Investment Operations		0.52			1.22			0.59			1.02			2.26
Less Distributions Declared to Shareholders
From net investment income		—			(0.39	)		(0.31	)		(0.17	)		(0.04	)
From net realized gains		(0.30	)		(0.72	)		(0.91	)		(0.03	)		(0.00	)(b)
Total Distributions Declared to Shareholders		(0.30	)		(1.11	)		(1.22	)		(0.20	)		(0.04	)
Net Asset Value, End of Period	$	12.84		$	12.62		$	12.51		$	13.14		$	12.32
Total Return (c)(d)		4.07	%(e)		9.91	%		4.56	%		8.27	%		22.38	%(e)
Ratios to Average Net Assets/Supplemental Data
Net expenses (f)(g)		1.00	%(h)		1.06	%		1.10	%		1.18	%		1.32	%(h)
Net investment income (g)		2.96	%(h)		2.99	%		2.39	%		1.55	%		1.06	%(h)
Waiver/reimbursement		0.23	%(h)		0.23	%		0.19	%		0.29	%		0.66	%(h)
Portfolio turnover rate		39	%(e)		66	%		96	%		67	%		61	%
Net assets at end of period (000's)	$	69,096		$	72,367		$	78,444		$	78,040		$	51,501

(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).

(c)  Total return at net asset value assuming all distributions reinvested and no initial sales charge or contingent deferred sales charge.

(d)  Had the Investment Adviser and/or Transfer Agent not 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.

See accompanying notes to financial statements.

75

Columbia Acorn Family of Funds

Financial Highlights, continued

Columbia Thermostat Fund

Class C Shares	(Unaudited) Six months ended June 30,			Year ended December 31,									Inception March 3, 2003 through December 31,
Selected data for a share outstanding throughout each period	2007			2006			2005			2004			2003
Net Asset Value, Beginning of Period	$	12.62		$	12.51		$	13.13		$	12.32		$	10.10
Income from Investment Operations
Net investment income (a)		0.17			0.36			0.29			0.19			0.11
Net realized and unrealized gain		0.33			0.84			0.29			0.81			2.15
Total from Investment Operations		0.50			1.20			0.58			1.00			2.26
Less Distributions Declared to Shareholders
From net investment income		—			(0.37	)		(0.29	)		(0.16	)		(0.04	)
From net realized gains		(0.30	)		(0.72	)		(0.91	)		(0.03	)		(0.00	)(b)
Total Distributions Declared to Shareholders		(0.30	)		(1.09	)		(1.20	)		(0.19	)		(0.04	)
Net Asset Value, End of Period	$	12.82		$	12.62		$	12.51		$	13.13		$	12.32
Total Return (c)(d)		3.91	%(e)		9.72	%		4.49	%		8.13	%		22.38	%(e)
Ratios to Average Net Assets/Supplemental Data
Net expenses (f)(g)		1.25	%(h)		1.25	%		1.25	%		1.25	%		1.32	%(h)
Net investment income (g)		2.71	%(h)		2.81	%		2.21	%		1.48	%		1.10	%(h)
Waiver/reimbursement		0.23	%(h)		0.23	%		0.19	%		0.26	%		0.66	%(h)
Portfolio turnover rate		39	%(e)		66	%		96	%		67	%		61	%
Net assets at end of period (000's)	$	25,991		$	27,375		$	28,316		$	31,161		$	20,087

(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).

(c)  Total return at net asset value assuming all distributions reinvested and no initial sales charge or contingent deferred sales charge.

(d)  Had the Investment Adviser and/or Transfer Agent not 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.

See accompanying notes to financial statements.

76

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, excluding Columbia Thermostat Fund, is to seek long-term growth of capital. The investment objective of Columbia Thermostat Fund is to provide long-term total return. The Fund pursues its investment objective by investing in shares of other mutual funds. As a "fund of funds" under normal circumstances, the Fund allocates at least 95% of its net assets among a selected group of stock and bond mutual funds ("portfolio funds") according to the current level of the Standard & Poor's 500 Stock Index in relation to predetermined ranges set by the Fund's investment 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.

The Funds may issue an unlimited number of shares. The Funds currently offer four classes of shares: Class A, Class B, Class C and Class Z.

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

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

Class C shares are subject to a CDSC on redemptions made within one year after purchase.

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

Columbia Acorn International and Columbia Acorn International Select impose a 2% redemption fee on Class A, Class B, Class C and Class Z shares that are redeemed within 60 days or less. See "Fund Policy on Trading of Fund Shares" as disclosed in the Funds' prospectuses for more information.

The financial highlights for Class Z shares are presented in a separate semiannual 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 each class bears certain expenses unique to that class such as distribution services, transfer agent, and certain other class specific expenses. Differences in class expenses may result in payment of different dividend distributions for each class. All the share classes of the Trust have equal rights with respect to voting subject to Fund or class specific matters.

2.  Significant Accounting Policies

>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 accordance with procedures established by the Board of Trustees. With respect to Columbia Thermostat Fund, investments in portfolio funds are valued at their net asset value as reported by the underlying funds. A security traded on a securities exchange or in the 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. A security for which there is no reported sale on the valuation date is valued at the latest bid quotation. A short-term debt obligation having a maturity of 60 days or less from the valuation date is valued at amortized cost, which approximate fair value. A security for which a market quotation is not readily available and any other assets are valued in accordance with procedures established by the Board of Trustees. The Trust has retained an independent statistical fair value pricing service 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 a "fair value," that value may be different from the last quoted market price for the security.

In September 2006, Statement of Financial Accounting Standards No. 157, Fair Value Measurements ("SFAS 157"), was issued. SFAS 157 is effective for fiscal years beginning after November 15, 2007. SFAS 157 defines fair value, establishes a framework for measuring fair value and expands disclosures about fair value measurements. Management is evaluating the

77

Columbia Acorn Family of Funds

Notes to Financial Statements (Unaudited), continued

impact the application of SFAS 157 will have on the Funds' financial statement disclosures.

>Repurchase agreements

The Funds may engage in repurchase agreement transactions. The Funds, through their custodians, receive delivery of underlying securities collateralizing repurchase agreements. The Funds' investment adviser determines that the value of the underlying securities is at all times at least equal to the resale price. In the event of default or bankruptcy by the other party 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 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.

>Security transactions and investment income

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

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

The Funds estimate components 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. The Funds will not incur any registration costs upon such resale.

>Use of estimates

The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America ("GAAP") requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results may differ from those estimates.

>Fund share valuation

Fund shares are sold and redeemed on a continuing basis at net asset value subject to any applicable sales charge. Net asset value per share is determined daily as of the close of trading on the New York Stock Exchange ("NYSE") on each day the NYSE is open for trading. All income, expenses (other than the Class A, Class B and Class C shares Rule 12b-1 service and distribution fees and Class A, Class B, Class C and Class Z shares transfer agent fees) and realized and unrealized gains (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. Redemption fees are accounted for as an addition to paid in capital for purposes of determining the net asset value of each class.

>Custody fees/credits

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

>Federal income taxes

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

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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-date.

>Indemnification

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

3.  Federal Tax Information

The tax character of distributions paid during the year ended December 31, 2006 was as follows:

	Ordinary Income*		Long-Term Capital Gains
(in thousands)
Columbia Acorn Fund	$	102,167	$	1,405,201
Columbia Acorn International		47,043		386,698
Columbia Acorn USA		—		33,093
Columbia Acorn International Select		198		—
Columbia Acorn Select		9,493		41,617
Columbia Thermostat Fund		7,031		9,506

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

The following capital loss carryforwards, determined as of December 31, 2006, 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		Columbia Acorn USA			Columbia Acorn International Select
(in thousands)
	2009	$	1,517	*	$	—
	2010		506			6,126
	2011		—			2,488
	TOTAL	$	2,023		$	8,614

*Of these carryforwards, $2,023 (expiring in 2009 and 2010) remains from Columbia Acorn USA's merger with Stein Roe Small Company Growth Fund on 7/26/2002. Utilization of Stein Roe Small Company Growth Fund's losses could be subject to limitations imposed by the Internal Revenue Code.

The following capital loss carryforwards were utilized during the year ended December 31, 2006.

(in thousands)
Columbia Acorn USA	$	506
Columbia Acorn International Select		16,995

The Funds adopted Financial Accounting Standards Board ("FASB") Interpretation No. 48, Accounting for Uncertainty in Income Taxes – an Interpretation of FASB Statement No. 109 ("FIN 48") effective June 29, 2007. FIN 48 requires management to determine whether a tax position of a Fund 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 in the technical merits of the position. The tax benefit to be recognized is measured as the largest amount of benefit that is greater than fifty percent likely of being realized upon ultimate settlement. FIN 48 must be applied to all existing tax positions upon initial adoption and the cumulative effect, if any, is to be reported as an adjustment to net assets. Management has evaluated the known implications of FIN 48 on its computation of net assets for the Funds. As a result of this evaluation, management believes that FIN 48 will not have any effect on the Fund's financial statements. However, management's conclusions regarding FIN 48 may be subject to review and adjustment at a later date based on factors including, but not limited to, further guidance expected from the FASB, new tax laws, regulations, and administrative interpretations (including relevant court decisions).

4.  Transactions with Affiliates

Columbia WAM furnishes continuing investment supervision to the Funds and is responsible for the overall management of the Funds' business affairs.

Effective August 1, 2007, under the Funds' investment advisory agreement, fees are accrued daily based on the Funds' average daily net assets and paid monthly to Columbia WAM at the annual rates shown in the table below for Columbia Acorn International Select:

Columbia Acorn International Select

Average Daily Net Assets		Annual Fee Rate
	Up to $500 million		0.940	%
	$500 million and over		0.900	%

For all of the Funds, and prior to August 1, 2007, for Columbia Acorn International Select, for the period covered by this report as provided under the Funds' investment advisory

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Columbia Acorn Family of Funds

Notes to Financial Statements (Unaudited), continued

agreement, fees were accrued daily based on the Funds' average daily net assets and paid monthly to Columbia WAM at the annual rates shown in the table below for each Fund.

Columbia Acorn Fund

Average Daily Net Assets	Annual Fee Rate
Up to $700 million		0.740	%
$700 million to $2 billion		0.690	%
$2 billion to $6 billion		0.640	%
$6 billion and over		0.630	%

Columbia Acorn International

Average Daily Net Assets	Annual Fee Rate
Up to $100 million		1.190	%
$100 million to $500 million		0.940	%
$500 million and over		0.740	%

Columbia Acorn USA

Average Daily Net Assets	Annual Fee Rate
Up to $200 million		0.940	%
$200 million to $500 million		0.890	%
$500 million to $2 billion		0.840	%
$2 billion to $3 billion		0.800	%
$3 billion and over		0.700	%

Columbia Acorn Select

Average Daily Net Assets	Annual Fee Rate
Up to $700 million		0.850	%
$700 million to $2 billion		0.800	%
$2 billion to $3 billion		0.750	%
$3 billion and over		0.700	%

Columbia Acorn International Select

All Average Daily Net Assets 0.940 %

Columbia Thermostat Fund

All Average Daily Net Assets 0.100 %

For the six months ended June 30, 2007, the Funds' annualized 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	0.80	%
Columbia Thermostat Fund	0.10	%

>Expense limit

Columbia WAM has voluntarily agreed to reimburse the ordinary operating expenses (exclusive of 12b-1 service and distribution fees, interest, taxes and extraordinary expenses, if any) exceeding 1.45% of the average daily net assets for Columbia Acorn International Select Class A, Class B and Class C shares and 1.35% of the average daily net assets for Columbia Acorn Select Class A, Class B and Class C shares. This arrangement may be modified or terminated by either the Funds or Columbia WAM on 30 days notice.

Columbia WAM has agreed to contractually reimburse the ordinary operating expenses (exclusive of Rule 12b-1 service and distribution fees, interest and fees on borrowings, and expenses associated with the Fund's investment in other investment companies) exceeding 0.25% of the average daily net assets of Columbia Thermostat Fund's Class A, Class B and Class C shares through April 30, 2008.

Expenses reimbursed by Columbia WAM for Columbia Thermostat Fund for the six months ended June 30, 2007, were $186,952.

Columbia WAM 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		0.05	%
$8 billion to $16 billion		0.04	%
$16 billion and over		0.03	%

For the six months ended June 30, 2007, each Fund's annualized effective administration fee rate was 0.04%. Columbia WAM has delegated to Columbia Management Advisors, LLC, an indirect, wholly owned subsidiary of BOA, responsibility to provide certain administrative services to the Funds.

Columbia Management Distributors, Inc. ("CMDI"), a wholly owned subsidiary of BOA, is the Funds' principal underwriter and receives no compensation on the sale of Class Z shares.

For the six months ended June 30, 2007, Columbia Acorn Fund, Columbia Acorn International, Columbia Acorn USA, Columbia Acorn International Select, Columbia Acorn Select and Columbia Thermostat have been advised that CMDI retained $578,819 in underwriting discounts on the sale of

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Class A shares and received CDSCs of $940,520 and $52,795, on Class B and Class C share redemptions, respectively.

Each Fund has adopted a Rule 12b-1 plan which requires it to pay CMDI a monthly service fee equal to 0.25% annually of the average daily net assets attributable to Class A, Class B and Class C shares. The Rule 12b-1 plan also requires each fund to pay CMDI 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.

Columbia Management Services, Inc. (the "Transfer Agent"), a wholly owned subsidiary of BOA, provides shareholder services to the Funds and has contracted with Boston Financial Data Services ("BFDS") to serve as sub-transfer agent. For such services, the Transfer Agent receives a fee, paid monthly, at the annual rate of $17.00 per open account. The Transfer Agent also receives reimbursement for certain out-of-pocket expenses and sub-transfer agency expenses. During the period January 1, 2007, through March 31, 2007, a portion of these fees were contractually waived.

Expenses waived by the Transfer Agent for the six months ended June 30, 2007, were as follows:

(in thousands)
Columbia Acorn Fund	$	737
Columbia Acorn International		56
Columbia Acorn USA		66
Columbia Acorn International Select		4
Columbia Acorn Select		100
Columbia Thermostat Fund		11

Certain officers and trustees of the Trust are also officers of Columbia WAM. The Trust makes no direct payments to its officers and trustees who are affiliated with Columbia WAM. For those trustees not affiliated with Columbia WAM, fees and expenses paid by the Funds for the six months ended June 30, 2007, were as follows:

(in thousands)
Columbia Acorn Fund	$	367
Columbia Acorn International		74
Columbia Acorn USA		30
Columbia Acorn International Select		15
Columbia Acorn Select		155
Columbia Thermostat Fund		18

The Board of Trustees appointed a Chief Compliance Officer to the Trust in accordance with federal securities regulations. The Funds, along with other affiliated funds, will 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 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 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 as specified by the trustee. Benefits under the deferred compensation plan are payable when a trustee ceases to be a member of the Board of Trustees.

An affiliate may include any company in which a Fund owns five percent or more of its outstanding voting securities. On June 30, 2007, 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 35, 44, 52 and 61, respectively.

During the six months ended June 30, 2007, 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 International	$	3,841	$	281
Columbia USA		115		—
Columbia Acorn Select		3,036		—

5.  Borrowing Arrangements

The Trust participates in a $150 million credit facility, which was entered into to facilitate portfolio liquidity. Interest is charged to each participating fund based on its borrowings at a rate per annum equal to the Federal Funds rate plus 0.50%. In addition, a commitment fee of 0.08% per annum is accrued and apportioned among the participating funds based on their pro-rata portion of the unutilized line of credit. The commitment fee is included in "Other expenses" in the Statements of Operations. No amounts were borrowed by the Funds under this facility for the six months ended June 30, 2007.

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Columbia Acorn Family of Funds

Notes to Financial Statements (Unaudited), continued

6.  Investment Transactions

The aggregate cost of purchases and proceeds from sales other than short-term obligations for the six months ended June 30, 2007, were:

Columbia Acorn Fund

(in thousands)
Investment securities
Purchases	$	2,113,213
Proceeds from sales		1,942,800

Columbia Acorn International

(in thousands)
Investment securities
Purchases	$	10,522,574
Proceeds from sales		747,816

Columbia Acorn USA

(in thousands)
Investment securities
Purchases	$	210,429
Proceeds from sales		140,893

Columbia Acorn International Select

(in thousands)
Investment securities
Purchases	$	82,074
Proceeds from sales		57,095

Columbia Acorn Select

(in thousands)
Investment securities
Purchases	$	541,174
Proceeds from sales		167,449

Columbia Thermostat Fund

(in thousands)
Investment securities
Purchases	$	72,382
Proceeds from sales		85,432

7.  Redemption Fees

For the six months ended June 30, 2007, the redemption fees imposed by Columbia Acorn International and Columbia Acorn International Select amounted to approximately $103,000 and $19,000, respectively, and are accounted for as additions to paid in capital.

8.  Other

For the six months ended June 30, 2007, Columbia Acorn Fund incurred two trading errors. Columbia Acorn Fund sold shares of Enerflex Systems resulting in a loss of $364. Additionally, Columbia Acorn Fund purchased shares of BioMarin resulting in a loss of $3,750. The Fund was reimbursed by Columbia WAM for the full amount of each loss.

These financial statements reflect certain adjusting journal entries recorded on the Columbia Thermostat Fund. While the impact of these adjusting entries was less than $.002 to each share class' NAV and therefore immaterial, they did cause the NAV's to round up by $0.01 for Class B, C and Z shares when compared to the NAV reported on the shareholder account statement you received by mail.

9.  Legal Proceedings

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

The Trust and Columbia WAM are also defendants in a class action lawsuit that alleges, in summary, that the Trust and Columbia WAM exposed shareholders of Columbia Acorn International Fund to trading by market timers by allegedly: (a) failing to properly evaluate daily whether a significant event affecting the value of the Fund's securities had occurred after foreign markets had closed but before the calculation of the Fund's net asset value ("NAV"); (b) failing to implement the Fund's portfolio valuation and share pricing policies and procedures; and (c) failing to know and implement applicable rules and regulations concerning the calculation of NAV (the "Fair Valuation Lawsuit"). The Seventh Circuit ruled that the plaintiffs' state law claims were preempted under federal law resulting in the dismissal of plaintiffs' complaint. Plaintiffs appealed the Seventh Circuit's ruling to the United States Supreme Court. The Supreme Cour t reversed the Seventh Circuit's ruling on jurisdictional grounds and the case was ultimately remanded to the state court.

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

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On April 4, 2006, the plaintiffs and the Columbia defendants named in the MDL Action executed an agreement in principle intended to fully resolve all of the lawsuits consolidated in the MDL Action as well as the Fair Valuation Lawsuit. The court entered a stay after the parties executed a settlement agreement. The settlement has not yet been finalized or approved by the court.

Columbia WAM, the Columbia Acorn Funds and the Trustees of the Trust are also defendants in a consolidated lawsuit filed in the federal district court of Massachusetts alleging that Columbia WAM used Fund assets to make undisclosed payments to brokers as an incentive for the brokers to market the Funds over other mutual funds to investors. The complaint alleges Columbia WAM and the Trustees of the Trust breached certain common law duties and federal laws.

On November 30, 2005, the court dismissed all of the claims alleged against all of the parties in the consolidated complaint. The parties subsequently executed a formal settlement agreement resolving all claims in the litigation and the plaintiffs dismissed their appeal. The settlement requires court approval, which has not yet been obtained.

On or about January 11, 2005, a putative class action lawsuit was filed in federal district court in Massachusetts against the Trust and the Trustees of the Trust, along with the Columbia Advisers, the sub-administrator of the Columbia Acorn Funds and the Wanger Advisors Funds. The plaintiffs allege that the defendants failed to submit Proof of Claims in connection with settlements of securities class action lawsuits filed against companies in which the Columbia Acorn Funds held positions. The complaint seeks compensatory and punitive damages, and the disgorgement of all fees paid to the Columbia Advisers.

Plaintiffs have voluntarily dismissed the Trust and its independent Trustees.

The Trust and Columbia WAM intend to defend these suits vigorously.

As a result of these matters, or any adverse publicity or other developments resulting from them, there may be

increased redemptions or reduced sales of Fund shares, which could increase transaction costs or operating expenses, or have other adverse consequences for the Funds. However, based on currently available information, the Columbia Acorn Trust believes that the likelihood that these lawsuits will have a material adverse impact on any fund is remote, and Columbia WAM believes that the lawsuits are not likely to materially affect its ability to provide investment management services to the Funds.

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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

June 2007

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Introduction

The New York Attorney General's Assurance of Discontinuance ("Order") entered into by Columbia Management Advisors, Inc. ("CMAI") and Columbia Management Distributors, Inc., ("CMDI" and collectively with "CMAI," "CMG") in February 2005, allows CMAI to manage or advise a mutual fund only if the trustees of the fund appoint a "Senior Officer" to perform specified duties and responsibilities. One of these responsibilities includes "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."

This is the first year that the Columbia Acorn Trust and Wanger Advisors Trust (collectively, the "Trusts") and each series thereof (the "Acorn Funds," "WAT Funds" or collectively, the "Funds") have been 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. The expenses can vary depending upon the class of shares held but usually include: (1) investment management or 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.

Columbia Wanger Asset Management, L.P. ("CWAM"), the adviser to the Funds, has proposed that with respect to the Acorn Funds, the Columbia Acorn Trust continue the existing separate agreements governing the first two categories listed above: an advisory agreement governing portfolio management, and an administration agreement governing certain administration and clerical services. Together the fees paid under these two agreements are referred to as "management fees." CWAM proposes that the WAT Funds continue the existing single agreement governing both investment advisory and administrative services. A single management fee would cover both services. Other fund expenses are governed by separate agreements, in particular agreements with two CWAM affiliates: CMDI, the broker-dealer that underwrites and distributes the Funds' shares, and Columbia Management Services, Inc. ("CMSI"), the Funds' transfer agent. In conformity with the terms of the Order, this evaluation, therefore, addresses only the advisory and administrative contracts, and does not extend to the other agreements.

According to the Order, the Senior Officer's evaluation must consider at least the 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 administrative fee contracts with CWAM in conformity with the requirements of the Order. This Report is

85

an annual evaluation required under the Order. In discharging their responsibilities, the independent Trustees have also consulted independent, outside counsel.

2006 Evaluation

This is the third annual evaluation prepared in connection with the Order. This evaluation follows the same structure as the earlier studies. Some areas are given more emphasis here, while others are given less. Still, the fundamental information gathered for this evaluation is largely the same as past years.

Process and Independence

The objectives of the Order are to insure the independent evaluation of the advisory fees paid by the Funds as well as to insure that all relevant factors are considered. In my view, this contract renewal 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 CWAM and CMG a comprehensive compilation of data regarding Fund performance and expenses, adviser profitability, and other information. The Board evaluated this information thoroughly and also explored CWAM's potential capacity restraints. 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 not influenced by the adviser. CWAM itself identified what it considers competing funds, and the Trustees considered that data as well.

In the course of its work, the Contract Committee gave careful consideration to the conclusions and recommendations contained in last year's evaluation. The Contract Committee gave particular emphasis to the issue of whether economies of scale were appropriately reflected in the Funds' fee schedules. Last year, the Board sought and CWAM agreed to additional breakpoints for two Funds, Acorn USA and Acorn Select. These breakpoints are above current asset levels, but clearly operate to share economies of scale with Fund shareholders. This year, at the Board's request, CWAM has proposed additional breakpoints for the WAT Funds, and Acorn International Select. This proposal is under consideration by the Board.

My evaluation of the advisory contract was shaped, as it was last year, 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 CMG or its affiliates, except for administrative purposes. 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 of the Board, 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, CMG 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 may not be increased before November 30, 2009. I have used these advisory fee levels – as modified last year to add certain breakpoints for Acorn USA and Acorn Select – in this evaluation because they are the fees in the current agreements that CWAM proposes should be continued. Hence, these fee levels are the starting point of an evaluation.

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Conclusions

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

1.  Performance. The domestic Funds generally have achieved outstanding performance. The Acorn Fund, Acorn USA, Acorn Select, Wanger Select and Wanger US Smaller Companies all rank very favorably against their peers over the past five years. Although Acorn USA and Wanger US Smaller Companies had a difficult year in 2006, these returns are not characteristic of these funds, both of which have shown improved performance during the first quarter of 2007. The international Funds have relatively weaker long term records than the domestic funds, but recently have improved significantly and their one year rankings are excellent. Overall then, performance of the Funds is excellent.

2.  Management Fees relative to Peers. The management fee rankings for several of the Acorn Funds are generally more favorable to shareholders than those of their peer group funds. Management fees do, however, vary by Fund. Acorn Fund is the least expensive and the Acorn USA the most expensive. Acorn Fund is very competitive, while Acorn USA and Acorn Select were ranked by both Lipper and Morningstar at or below the median, and therefore impose higher fees than do the majority of their competitors. The WAT Funds also lag their competitors and impose higher fees than their peers.

3.  Administrative Fees. The Acorn Funds' administrative fee, which is uniform across all Funds, is at a level comparable to or less expensive than the fees imposed by their peers, provides for appropriate services to Funds, and affords breakpoints that lower the fee as assets increase. The WAT Funds pay a single fee for advisory and administrative services and hence do not benefit from administrative fee breakpoints, nor is it possible to assess their administrative costs relative to competitors.

4.  Management Fees relative to Institutional and Other Mutual Fund Accounts. CWAM's focus is on its mutual funds. It does not actively seek to manage separate or institutional accounts. 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 particular institutional account is significant in size and has been under CWAM's management for over 25 years.

5.  Costs to CWAM and its Affiliates. CWAM's direct costs do not appear excessive. Overhead and indirect costs allocated to CWAM by its parent organizations, however, are significant and increasing. CWAM's affiliates report operating losses and therefore do not appear to profit from CWAM's advisory agreement with the Funds.

6.  Profit Margins. CWAM's firm-wide, pre-marketing expense profit margins are at the top of the industry, though these comparisons are hampered by limited industry data. High profit margins are not unexpected for firms that manage large, successful funds and have provided outstanding investment performance for investors.

7.  Economies of Scale. Economies of scale do exist at CWAM and will expand as the assets of the Funds get larger. They are, however, only partially reflected in the management fee schedule for the Acorn Funds and not reflected at all in two of the four WAT Funds. Breakpoints above current asset levels have, however, been added to the more expensive funds, Acorn Select and Acorn USA. Nonetheless, if Fund assets continue to grow, under the Funds' current fee schedules, all Fund shareholders might not benefit in a manner generally commensurate with CWAM's increased profits. Management has proposed additional breakpoints for some of the Funds that, if implement, would result in greater sharing of economies of scale.

87

8.  Nature and Quality of Services. This category includes a variety of considerations that are difficult to quantify, yet can have a significant bearing on the performance of the Acorn Funds. Several areas merit comment.

  a.  Capacity. The Funds have continued to grow, posing ever greater challenges in deploying assets effectively. While trends here merit continued monitoring, CWAM appears to be managing assets effectively.

  b.  Compliance. CWAM has a reasonably designed compliance program that protects shareholders.

  c.  Administrative Services. The Funds benefit from a variety of administrative services that are performed by CWAM and CMAI.

9.  Process. In my opinion, the process of negotiating an advisory contract for the Funds has been conducted thoroughly and at arms' length. Further, the Trustees have sufficient information to evaluate management's proposal, and negotiate contract terms that are in the best interests of fund shareholders.

Recommendations

I believe the Trustees should:

1.  Continue to consider additional ways to restructure the advisory fee beyond the current breakpoint schedule to reflect more fully economies of scale.

2.  Consider unbundling of the advisory and administrative fees paid by the WAT Funds.

3.  Review the disparity in management fee levels between the Acorn International Fund and its related annuity-based fund, WAT International Small Cap Fund.

4.  Continue to monitor CWAM's capacity limitations to insure that the Funds' expanding assets do not impair investment performance.

Robert P. Scales
Senior Vice President,
Chief Legal Officer
and General Counsel

June 18, 2007

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90

Columbia Acorn Family of Funds

Class A, B and C Share Information

Minimum Initial Investment in
Columbia Acorn International,
Columbia Acorn International
Select and Columbia
Thermostat Fund	$2,500† $1,000 for an IRA
Minimum Initial Investment in Columbia Acorn Fund and Columbia Acorn USA	$75,000†
Minimum Initial Investment in Columbia Acorn Select	$100,000*†
Minimum Subsequent Investment in all Funds	$50
Exchange Fee	None

Columbia Acorn Fund	Class A			Class B			Class C
Management Fees		0.64	%		0.64	%		0.64	%
Distribution and Service (12b-1) Fees		0.25	%		0.75	%		1.00	%
Other Expenses		0.13	%		0.21	%		0.16	%
Net Expense Ratio		1.02	%		1.60	%		1.80	%
Columbia Acorn International	Class A			Class B			Class C
Management Fees		0.76	%		0.76	%		0.76	%
Distribution and Service (12b-1) Fees		0.25	%		0.75	%		1.00	%
Other Expenses		0.18	%		0.28	%		0.20	%
Net Expense Ratio		1.19	%		1.79	%		1.96	%
Columbia Acorn USA	Class A			Class B			Class C
Management Fees		0.86	%		0.86	%		0.86	%
Distribution and Service (12b-1) Fees		0.25	%		0.75	%		1.00	%
Other Expenses		0.14	%		0.25	%		0.18	%
Net Expense Ratio		1.25	%		1.86	%		2.04	%
Columbia Acorn International Select	Class A			Class B			Class C
Management Fees		0.94	%		0.94	%		0.94	%
Distribution and Service (12b-1) Fees		0.25	%		0.75	%		1.00	%
Other Expenses		0.29	%		0.41	%		0.33	%
Net Expense Ratio		1.48	%		2.10	%		2.27	%
Columbia Acorn Select	Class A			Class B			Class C
Management Fees		0.80	%		0.80	%		0.80	%
Distribution and Service (12b-1) Fees		0.25	%		0.75	%		1.00	%
Other Expenses		0.15	%		0.25	%		0.19	%
Net Expense Ratio		1.20	%		1.80	%		1.99	%
Columbia Thermostat	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, 2007, and for Columbia Thermostat Fund include the effect of Columbia Wanger Asset Management's undertaking to reimburse the Fund for any ordinary operating expenses (exclusive of Rule 12b-1 service and distribution fees, interest and fees on borrowings and expenses associated with the Fund's investment in other investment companies), net of custody fees paid indirectly, in excess of the annual rate of 0.25% of the average daily net assets. Columbia Thermostat Fund's reimbursement arrangement is contractual through April 30, 2008. The Funds' adviser and/or any affiliates have agreed to contractually waive a portion of "other expenses" through March 31, 2007.

  *  Effective June 25, 2007, the board of trustees voted to increase the minimum initial investment for Columbia Acorn Select from $50,000 to $100,000.

  **  Does not include estimated fees and expenses of 0.72% incurred by the Fund from the underlying portfolio funds.

  †  Certain exclusions may apply.

91

Columbia Acorn Family of Funds

Trustees

Robert E. Nason

Chairman

Allan B. Muchin

Vice Chairman

Laura M. Born

Maureen M. Culhane

Margaret Eisen

Jerome Kahn, Jr.

Steven N. Kaplan

David C. Kleinman

Charles P. McQuaid

James A. Star

Ralph Wanger

Patricia H. Werhane

John A. Wing

Officers

Charles P. McQuaid

President

Ben Andrews

Vice President

Michael G. Clarke

Assistant Treasurer

Jeffrey R. Coleman

Assistant Treasurer

J. Kevin Connaughton

Assistant Treasurer

P. Zachary Egan

Vice President

Peter T. Fariel

Assistant Secretary

John M. Kunka

Assistant Treasurer

Joseph C. LaPalm

Vice President

Bruce H. Lauer

Vice President, Treasurer and Secretary

Louis J. Mendes III

Vice President

Robert A. Mohn

Vice President

Christopher J. Olson

Vice President

Linda K. Roth-Wiszowaty

Assistant Secretary

Robert P. Scales

Senior Vice President, Chief Compliance Officer
and General Counsel

Investment Adviser

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

1-800-922-6769

Distributor

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

Transfer Agent, Dividend Disbursing Agent

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

1-800-345-6611

Legal Counsel

Bell, Boyd & Lloyd LLP
Chicago, Illinois

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 from the Fund's website.

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.

Please consider the investment objectives, risks, charges and expenses for the funds carefully before investing. Contact your financial advisor for a prospectus, which contains this and other important information about the funds. You should read it carefully before you invest.

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

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

www.columbiafunds.com

Our e-mail address is:

ServiceInquiries@ColumbiaManagement.com

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

92

Columbia Acorn Family of Funds

Class ABC Shares

Semiannual Report – June 30, 2007

Columbia Management_®

PRESORTED

FIRST-CLASS MAIL

U.S. POSTAGE PAID

HOLLISTON, MA

PERMIT NO. 20

©2007 Columbia Management Distributors, Inc.

One Financial Center, Boston, MA 02111-2621

800-345-6611 www.columbiafunds.com

SHC-44/132915-0607 07/43076

Item 2. Code of Ethics.

Not applicable for semi-annual reports.

Item 3. Audit Committee Financial Expert.

Not applicable for semi-annual reports.

Item 4. Principal Accountant Fees and Services.

Not applicable for semi-annual reports.

Item 5. Audit Committee of Listed Registrants.

Not applicable.

Item 6. Schedule of Investments

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.

Item 7. Disclosure of Proxy Voting Policies and Procedures for Closed-End Management Investment Companies.

Not applicable.

Item 8. Portfolio Managers of Closed-End Management Investment Companies.

Not applicable.

Item 9. Purchases of Equity Securities by Closed-End Management Investment Company and Affiliated Purchasers.

Not applicable.

Item 10. Submission of Matters to a Vote of Security Holders.

There have not been any material changes to the procedures by which shareholders may recommend nominees to the registrant’s board of directors, since those procedures were last disclosed in response to requirements of Item 7(d)(2)(ii)(G) of Schedule 14A or this Item.

Item 11. Controls and Procedures.

(a)The registrant’s principal executive officer and principal financial officers, based on their evaluation of the registrant’s disclosure controls and procedures as of a date within 90 days of the filing of this report, have concluded that such controls and procedures are adequately designed to ensure that information required to be disclosed by the registrant in Form N-CSR is accumulated and communicated to the registrant’s management, including the principal executive officer and principal financial officer, or persons performing similar functions, as appropriate to allow timely decisions regarding required disclosure.

(b)There was no change in the registrant’s internal control over financial reporting that occurred during the registrant’s second fiscal quarter of the period covered by this report that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting.

Item 12. Exhibits.

(a)(1) Code of ethics required to be disclosed under Item 2 of Form N-CSR: Not applicable at this time.

(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 24, 2007

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 24, 2007
By (Signature and Title)	/s/ Bruce H. Lauer
	Bruce H. Lauer, Treasurer

Date August 24, 2007

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 24, 2007	/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 24, 2007	/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, 2007, 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 24, 2007	/s/ Charles P. McQuaid
	Charles P. McQuaid, President
Date:  August 24, 2007	/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.