Columbia Thermostat Fund NCSRS Certified semi-annual shareholder report (management investment company)

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)

227 W. Monroe Street Suite 3000 Chicago, IL					60606
(Address of principal executive offices)					(Zip code)

Paul B. Goucher, Esq. Columbia Management Investment Advisers, LLC 100 Park Avenue New York, New York 10017 P. Zachary Egan Columbia Acorn Trust 227 West Monroe Street, Suite 3000 Chicago, Illinois 60606 Mary C. Moynihan Perkins Coie LLP 700 13th Street, NW Suite 600 Washington, DC 20005
(Name and address of agent for service)

Registrant’s telephone number, including area code:				(312) 634-9200

Date of fiscal year end:	December 31

Date of reporting period:		June 30, 2015

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.

SEMIANNUAL REPORT

June 30, 2015

COLUMBIA ACORN FAMILY OF FUNDS

Class A, B, C, I, R, R4, R5, Y and Z Shares
Managed by Columbia Wanger Asset Management, LLC

Columbia Acorn® Fund

Columbia Acorn International®

Columbia Acorn USA®

Columbia Acorn International Select^SM

Columbia Acorn Select^SM

Columbia Thermostat Fund^SM

Columbia Acorn Emerging Markets Fund^SM

Columbia Acorn European Fund^SM

COLUMBIA ACORN FAMILY OF FUNDS

NET ASSET VALUE PER SHARE as of 6/30/15

	Columbia Acorn® Fund		Columbia Acorn International®		Columbia Acorn USA®		Columbia Acorn International Select^SM		Columbia Acorn Select^SM		Columbia Thermostat Fund^SM		Columbia Acorn Emerging Markets Fund^SM		Columbia Acorn European Fund^SM
Class A	$	30.63	$	43.41	$	30.38	$	22.76	$	20.52	$	14.72	$	12.34	$	15.23
Class B	$	26.51	$	41.87	$	26.07	$	21.37	$	17.26	$	14.79		N/A		N/A
Class C	$	25.87	$	41.69	$	25.84	$	21.23	$	16.91	$	14.77	$	12.23	$	15.05
Class I	$	32.53	$	43.57	$	32.65	$	23.06	$	22.00		N/A	$	12.39	$	15.24
Class R		N/A	$	43.32		N/A		N/A		N/A		N/A		N/A		N/A
Class R4	$	33.02	$	43.80	$	33.17	$	23.22	$	22.37	$	14.62	$	12.46	$	15.31
Class R5	$	33.07	$	43.50	$	33.20	$	23.21	$	22.41	$	14.63	$	12.45	$	15.39
Class Y	$	33.15	$	43.85	$	33.30	$	23.20	$	22.50	$	14.62	$	12.35		N/A
Class Z	$	32.44	$	43.52	$	32.45	$	23.07	$	21.87	$	14.55	$	12.38	$	15.25

Class I shares are available only to the Columbia funds, such as Columbia Thermostat Fund, and are not available to individual investors. Class R, R4, R5, Y and Z shares are sold at net asset value and have limited eligibility. Please see the Funds' prospectuses for details. The Columbia Acorn Family of Funds offer multiple share classes, not all necessarily available through all financial intermediaries, and the ratings assigned to the various share classes by mutual fund rating agencies may vary. Contact us for details.

2015 YEAR-END CAPITAL GAIN DISTRIBUTION ESTIMATE as of 7/31/15¹

To assist shareholders in year-end planning, we are providing capital gain distribution estimates for the Funds. The estimates below reflect undistributed net realized capital gains through July 31, 2015 and may not include all required tax adjustments. Distributions are not the result of material changes in investment strategy. The Funds have sold investments in order to satisfy shareholder redemptions, which has triggered the realization of capital gains. The Funds continue to have material unrealized gains in certain of their holdings. Please note that these figures are subject to change as required capital gain distributions, including appropriate tax adjustments, are determined as of October 31, 2015. In addition, further sales of Fund investments through October 31 and changes in outstanding Fund shares through the record date will affect the final per share distributions. Distributions will not be considered final until their declaration on the ex-dividend date for the capital gain distribution.

Fund Name	Expected Record Date and Payable Date	Range of Estimated Total Capital Gain Distribution²			Class A Share NAV at 7/31		Range of Total Capital Gain Distribution as % of 7/31 Class A NAV
Columbia Acorn Fund	December 2015	$	8.00	to $9.00	$	30.36		26.35	% to 29.64%
Columbia Acorn International	December 2015	$	2.60	to $2.85	$	42.63		6.10	% to 6.69%
Columbia Acorn USA	December 2015	$	5.50	to $6.50	$	30.06		18.30	% to 21.62%
Columbia Acorn International Select	December 2015		None		$	22.19		—
Columbia Acorn Select	December 2015	$	4.00	to $4.75	$	20.28		19.72	% to 23.42%
Columbia Acorn Thermostat Fund	December 2015	$	0.05	to $0.10	$	14.77		0.34	% to 0.68%
Columbia Acorn Emerging Markets Fund	December 2015		None		$	11.72		—
Columbia Acorn European Fund	December 2015		None		$	15.27		—

¹ None of Columbia Wanger Asset Management, the Columbia Acorn Funds or Columbia Threadneedle Investments provide tax or legal advice. Please consult a tax advisor or tax attorney for specific tax or legal advice.

² Estimated amounts shown include only long-term capital gains for all Columbia Acorn Funds, except Columbia Acorn Select, for which the estimated total range shown includes between $0.70 and $0.95 of short-term capital gains.

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

Acorn®, Acorn USA® and Acorn International® are service marks owned and registered by Columbia Acorn Trust.

COLUMBIA ACORN FAMILY OF FUNDS

TABLE OF CONTENTS

Share Class Performance					2
Fund Performance vs. Benchmarks					3
Columbia Acorn® Fund
In a Nutshell					4
At a Glance					5
Major Portfolio Changes					28
Statement of Investments					31
Columbia Acorn International®
In a Nutshell					6
At a Glance					7
Major Portfolio Changes					39
Statement of Investments					41
Portfolio Diversification					49
Columbia Acorn USA®
In a Nutshell					8
At a Glance					9
Major Portfolio Changes					50
Statement of Investments					51
Columbia Acorn International Select^SM
In a Nutshell					10
At a Glance					11
Major Portfolio Changes					56
Statement of Investments					57
Portfolio Diversification					61
Columbia Acorn Select^SM
In a Nutshell					12
At a Glance					13
Major Portfolio Changes					62
Statement of Investments					63

Columbia Thermostat Fund^SM
In a Nutshell					14
At a Glance					15
Statement of Investments					67
Columbia Acorn Emerging Markets Fund^SM
In a Nutshell					16
At a Glance					17
Major Portfolio Changes					69
Statement of Investments					71
Portfolio Diversification					76
Columbia Acorn European Fund^SM
In a Nutshell					18
At a Glance					19
Major Portfolio Changes					77
Statement of Investments					79
Portfolio Diversification					83
Squirrel Chatter: Battery Technology and its Implications					20
Mid-Year Distributions					23
Understanding Your Expenses					25
Columbia Acorn Family of Funds^SM
Statements of Assets and Liabilities					84
Statements of Operations					86
Statements of Changes in Net Assets					88
Financial Highlights					94
Notes to Financial Statements					110
Board of Approval of the Advisory Agreement					120
Results of Special Meeting of Shareholders					125
Description of Indexes					126
Expense Information					127

A COMMENT ON TRADING VOLUMES

Market conditions are always changing and vary by country and industry sector, and investing in international markets involves unique risks. In the wake of the 2007-2009 financial crisis, trading volumes in both emerging and developed international markets declined significantly and have stayed at generally reduced levels since then. Although it is difficult to accurately assess trends in trading volumes in foreign markets, because some amount of activity has migrated to alternative trading venues, a reduction in trading volumes poses challenges to the Funds. This is particularly so because the Funds focus on small- and mid-cap companies that usually have lower trading volumes and often take sizeable positions in portfolio companies. As a result of lower trading volumes, it may take longer to buy or sell securities, which can exacerbate a Fund's exposure to volatile markets. A Fund may also be limited in its ability to execute favorable trades in portfolio securities in response to changes in company prices and fundamentals. If a Fund is forced to sell securities to meet redemption requests or other cash needs, or in the case of an event affecting liquidity in a particular market or markets, it may be forced to dispose of those securities under disadvantageous circumstances and at a loss. As a Fund grows in size, these considerations take on increasing significance and may adversely impact performance.

COLUMBIA ACORN FAMILY OF FUNDS

SHARE CLASS PERFORMANCE Average Annual Total Returns through 6/30/15

	Class A						Class B						Class C						Class I			Class R			Class R4			Class R5			Class Y			Class Z
	Without Sales Charge			With Sales Charge			Without Sales Charge			With Sales Charge			Without Sales Charge			With Sales Charge
Columbia Acorn® Fund
Year to date*		6.45	%		0.32	%		6.04	%		1.04	%		6.07	%		5.07	%		6.63	%		N/A			6.56	%		6.58	%		6.63	%		6.61	%
1 year		4.45	%		-1.56	%		3.64	%		-0.48	%		3.69	%		2.87	%		4.81	%		N/A			4.68	%		4.76	%		4.81	%		4.73	%
5 years		15.21	%		13.85	%		14.51	%		14.28	%		14.37	%		14.37	%		15.62	%		N/A			15.52	%		15.57	%		15.60	%		15.55	%
10 years		8.48	%		7.83	%		7.80	%		7.80	%		7.65	%		7.65	%		8.82	%		N/A			8.78	%		8.80	%		8.81	%		8.79	%
Columbia Acorn International®
Year to date*		5.05	%		-0.99	%		4.61	%		-0.39	%		4.63	%		3.63	%		5.23	%		4.86	%		5.12	%		5.19	%		5.24	%		5.18	%
1 year		-5.29	%		-10.74	%		-6.04	%		-10.48	%		-6.00	%		-6.89	%		-4.92	%		-5.65	%		-5.12	%		-4.99	%		-4.92	%		-5.02	%
5 years		10.21	%		8.91	%		9.43	%		9.15	%		9.39	%		9.39	%		10.65	%		9.85	%		10.52	%		10.59	%		10.61	%		10.57	%
10 years		8.82	%		8.18	%		8.09	%		8.09	%		7.99	%		7.99	%		9.22	%		8.49	%		9.16	%		9.19	%		9.21	%		9.19	%
Columbia Acorn USA®
Year to date*		7.14	%		0.97	%		6.45	%		1.45	%		6.76	%		5.76	%		7.34	%		N/A			7.26	%		7.32	%		7.33	%		7.25	%
1 year		7.96	%		1.74	%		6.72	%		2.50	%		7.22	%		6.38	%		8.39	%		N/A			8.19	%		8.28	%		8.36	%		8.21	%
5 years		16.67	%		15.30	%		15.78	%		15.56	%		15.84	%		15.84	%		17.13	%		N/A			17.00	%		17.03	%		17.07	%		16.98	%
10 years		7.50	%		6.87	%		6.74	%		6.74	%		6.70	%		6.70	%		7.87	%		N/A			7.81	%		7.82	%		7.84	%		7.80	%
Columbia Acorn International Select^SM
Year to date*		3.70	%		-2.24	%		3.36	%		-1.64	%		3.36	%		2.36	%		3.88	%		N/A			3.86	%		3.90	%		3.91	%		3.88	%
1 year		-12.04	%		-17.09	%		-12.67	%		-16.52	%		-12.70	%		-13.47	%		-11.75	%		N/A			-11.80	%		-11.74	%		-11.71	%		-11.76	%
5 years		8.86	%		7.58	%		8.14	%		7.85	%		8.02	%		8.02	%		9.27	%		N/A			9.19	%		9.23	%		9.25	%		9.21	%
10 years		7.76	%		7.12	%		7.06	%		7.06	%		6.92	%		6.92	%		8.14	%		N/A			8.10	%		8.12	%		8.13	%		8.11	%
Columbia Acorn Select^SM
Year to date*		5.96	%		-0.12	%		5.50	%		0.72	%		5.55	%		4.60	%		6.19	%		N/A			6.08	%		6.12	%		6.14	%		6.07	%
1 year		6.96	%		0.80	%		6.05	%		2.06	%		6.15	%		5.36	%		7.35	%		N/A			7.19	%		7.31	%		7.33	%		7.25	%
5 years		12.69	%		11.36	%		11.91	%		11.69	%		11.84	%		11.84	%		13.12	%		N/A			12.98	%		13.03	%		13.06	%		13.01	%
10 years		7.67	%		7.04	%		6.95	%		6.95	%		6.84	%		6.84	%		8.04	%		N/A			7.97	%		7.99	%		8.01	%		7.98	%
Columbia Thermostat Fund^SM
Year to date*		1.08	%		-4.75	%		0.81	%		-4.13	%		0.74	%		-0.25	%		N/A			N/A			1.23	%		1.23	%		1.23	%		1.23	%
1 year		2.46	%		-3.43	%		1.94	%		-2.94	%		1.70	%		0.72	%		N/A			N/A			2.74	%		2.68	%		2.74	%		2.69	%
5 years		10.51	%		9.22	%		9.94	%		9.67	%		9.67	%		9.67	%		N/A			N/A			10.78	%		10.79	%		10.82	%		10.78	%
10 years		6.26	%		5.63	%		5.72	%		5.72	%		5.47	%		5.47	%		N/A			N/A			6.53	%		6.53	%		6.55	%		6.53	%
Columbia Acorn Emerging Markets Fund^SM
Year to date*		-2.99	%		-8.59	%		N/A			N/A			-3.32	%		-4.29	%		-2.82	%		N/A			-2.88	%		-2.89	%		-2.83	%		-2.83	%
1 year		-10.09	%		-15.25	%		N/A			N/A			-10.73	%		-11.62	%		-9.80	%		N/A			-9.87	%		-9.85	%		-9.77	%		-9.85	%
Life of Fund		6.10	%		4.49	%		N/A			N/A			5.34	%		5.34	%		6.50	%		N/A			6.45	%		6.46	%		6.48	%		6.40	%
Columbia Acorn European Fund^SM
Year to date*		6.66	%		0.56	%		N/A			N/A			6.29	%		5.29	%		6.80	%		N/A			6.77	%		6.81	%		N/A			6.80	%
1 year		-3.84	%		-9.35	%		N/A			N/A			-4.57	%		-5.52	%		-3.54	%		N/A			-3.57	%		-3.57	%		N/A			-3.58	%
Life of Fund		12.32	%		10.61	%		N/A			N/A			11.50	%		11.50	%		12.64	%		N/A			12.62	%		12.61	%		N/A			12.61	%

*Not annualized.

Returns for Class A shares are shown with and without the maximum initial sales charge of 5.75%. Returns for Class B shares are shown with and without the applicable contingent deferred sales charge (CDSC) of 5.00% in the first year, declining to 1.00% in the sixth year and eliminated thereafter. Returns for Class C shares are shown with and without the maximum CDSC of 1.00% for the first year after purchase. The Funds' other classes are not subject to sales charges and have limited eligibility. Please see the Funds' prospectuses for details. Performance for different share classes will vary based on differences in sales charges and certain fees associated with each class.

All results shown assume reinvestment of distributions during the period. Returns do not reflect the deduction of taxes that a shareholder may pay on Fund distributions or on the redemption of Fund shares. Performance results may reflect the effect of any fee waivers or reimbursements of Fund expenses by the investment manager and/or any of its affiliates. Absent these fee waivers and/or expense reimbursement arrangements, performance results may have been lower. Please see Page 127 of this report for information on contractual fee waiver and expense reimbursement agreements in place on June 30, 2015, for Columbia Thermostat Fund, Columbia Acorn Emerging Markets Fund and Columbia Acorn European Fund and voluntary fee waiver and expense reimbursement arrangements in place for Columbia Acorn International, Columbia Acorn International Select and Columbia Acorn Select.

The performance information shown represents past performance and is not a guarantee of future results. The investment return and principal value of your investment will fluctuate so that shares, when redeemed, may be worth more or less than their original cost. Current performance may be lower or higher than the performance data shown. You may obtain performance information current to the most recent month-end by contacting your financial intermediary, visiting columbiathreadneedle.com/us or calling 800.922.6769.

The returns shown include the returns of each Fund's Class Z shares, each Fund's oldest share class, in cases where the inception date of the Fund is earlier than the inception date of the particular share class or where a period shown dates to before the inception date of the share class. These returns are adjusted to reflect any higher class-related operating expenses of the newer share classes, as applicable. Please visit columbiathreadneedleus.com/investment-products/mutual-funds/appended-performance for more information.

Continued on Page 3.

FUND PERFORMANCE VS. BENCHMARKS Class Z Average Annual Total Returns through 6/30/15

Class Z Shares	2nd quarter*			Year to date*			1 year			5 years			10 years			Life of Fund
Columbia Acorn® Fund (ACRNX) (6/10/70)		2.54	%		6.61	%		4.73	%		15.55	%		8.79	%		14.58	%
Russell 2500 Index		-0.34	%		4.81	%		5.92	%		17.85	%		9.09	%		N/A
S&P 500 Index**		0.28	%		1.23	%		7.42	%		17.34	%		7.89	%		10.96	%
Russell 2000 Index		0.42	%		4.75	%		6.49	%		17.08	%		8.40	%		N/A
Lipper Mid-Cap Growth Funds Index		0.44	%		5.54	%		9.19	%		16.74	%		9.57	%		N/A
Columbia Acorn International® (ACINX) (9/23/92)		0.81	%		5.18	%		-5.02	%		10.57	%		9.19	%		10.87	%
S&P Global Ex-U.S. Between $500M and $5B Index		2.91	%		7.97	%		-1.52	%		9.91	%		8.20	%		8.48	%
S&P Global Ex-U.S. SmallCap Index		4.55	%		8.42	%		-2.26	%		10.54	%		7.84	%		7.97	%
MSCI EAFE Index (Net)		0.62	%		5.52	%		-4.22	%		9.54	%		5.12	%		6.09	%
Lipper International Small/Mid Growth Funds Index		4.35	%		10.16	%		-0.41	%		13.26	%		8.91	%		N/A
Columbia Acorn USA® (AUSAX) (9/4/96)		2.02	%		7.25	%		8.21	%		16.98	%		7.80	%		10.93	%
Russell 2000 Index		0.42	%		4.75	%		6.49	%		17.08	%		8.40	%		8.72	%
Lipper Small-Cap Growth Funds Index		1.71	%		7.54	%		9.63	%		17.43	%		8.29	%		7.44	%
Columbia Acorn Int'l Select^SM (ACFFX) (11/23/98)		2.37	%		3.88	%		-11.76	%		9.21	%		8.11	%		8.77	%
S&P Developed Ex-U.S. Between $2B and $10B Index		2.27	%		8.00	%		-1.35	%		10.68	%		6.99	%		7.68	%
MSCI EAFE Index (Net)		0.62	%		5.52	%		-4.22	%		9.54	%		5.12	%		4.37	%
Lipper International Small/Mid Growth Funds Index		4.35	%		10.16	%		-0.41	%		13.26	%		8.91	%		10.35	%
Columbia Acorn Select^SM (ACTWX) (11/23/98)		3.16	%		6.07	%		7.25	%		13.01	%		7.98	%		10.35	%
S&P MidCap 400 Index		-1.06	%		4.20	%		6.40	%		17.82	%		9.74	%		10.55	%
S&P 500 Index**		0.28	%		1.23	%		7.42	%		17.34	%		7.89	%		5.46	%
Lipper Mid-Cap Core Funds Index		-0.57	%		3.43	%		5.21	%		16.45	%		8.67	%		9.14	%
Columbia Thermostat Fund^SM (COTZX) (9/25/02)		-0.26	%		1.23	%		2.69	%		10.78	%		6.53	%		7.77	%
S&P 500 Index		0.28	%		1.23	%		7.42	%		17.34	%		7.89	%		9.72	%
Barclays U.S. Aggregate Bond Index		-1.68	%		-0.10	%		1.86	%		3.35	%		4.44	%		4.48	%
Lipper Flexible Portfolio Funds Index		-0.46	%		1.01	%		-0.59	%		9.87	%		6.26	%		7.79	%
50/50 Blended Benchmark		-0.70	%		0.66	%		4.73	%		10.36	%		6.46	%		7.35	%
Columbia Acorn Emerging Markets Fund^SM (CEFZX) (8/19/11)		-2.06	%		-2.83	%		-9.85	%		—			—			6.40	%
S&P Emerging Markets Between $500M and $5B Index		1.17	%		3.05	%		-2.71	%		—			—			3.68	%
MSCI Emerging Markets Small Cap Index (Net)		4.50	%		8.25	%		0.34	%		—			—			3.10	%
Lipper Emerging Markets Index		0.66	%		1.72	%		-7.05	%		—			—			2.35	%
Columbia Acorn European Fund^SM (CAEZX) (8/19/11)		2.30	%		6.80	%		-3.58	%		—			—			12.61	%
S&P Europe Between $500M and $5B Index		5.03	%		10.62	%		-1.86	%		—			—			14.88	%
Euromoney Smaller European Companies (inc. UK) Index		5.49	%		10.15	%		-5.39	%		—			—			12.92	%
Lipper European Region Index		1.89	%		6.42	%		-4.28	%		—			—			12.26	%

The inception dates for Class A, B and C shares (if offered) are as follows: Columbia Acorn Fund, Columbia Acorn International, Columbia Acorn USA, Columbia Acorn International Select and Columbia Acorn Select, 10/16/00; Columbia Thermostat Fund, 3/3/03; Columbia Acorn Emerging Markets Fund and Columbia Acorn European Fund, 8/19/11. The inception dates for Class I shares are as follows: Columbia Acorn Fund, Columbia Acorn International, Columbia Acorn USA, Columbia Acorn International Select and Columbia Acorn Select, 9/27/10; Columbia Acorn Emerging Markets Fund and Columbia Acorn European Fund, 8/19/11. The inception date for Class R shares for Columbia Acorn International is 8/2/11. The inception date for Class R4, R5 and Y shares (if offered) is as follows: Columbia Acorn Fund, Columbia Acorn USA, Columbia Acorn International Select, Columbia Acorn Select, Columbia Thermostat Fund, Columbia Acorn Emerging Markets Fund and Columbia Acorn European Fund, 11/8/12, except that Class Y shares of Columbia Acorn Emerging Markets Fund commenced operations on 6/13/13 and Class R4 shares of Columbia Acorn European Fund commenced operations on 6/25/14. The inception date for Class R5 shares of Columbia Acorn International is 8/2/11. The inception date for Class R4 and Y shares of Columbia Acorn International is 11/8/12. The inception date for Class Z shares is as follows: Columbia Acorn Fund, 6/10/70; Columbia Acorn International, 9/23/92; Columbia Acorn USA, 9/4/96; Columbia Acorn International Select and Columbia Acorn Select, 11/23/98; Columbia Thermostat Fund, 9/25/02; Columbia Acorn Emerging Markets Fund and Columbia Acorn European Fund, 8/19/11.

*Not annualized.

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

Please see Page 126 for a description of the indexes listed above.

COLUMBIA ACORN® FUND

IN A NUTSHELL


Robert A. Mohn* Co-Portfolio Manager				P. Zachary Egan Co-Portfolio Manager

Fritz Kaegi Co-Portfolio Manager				David L. Frank Co-Portfolio Manager

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

Market risk may affect a single issuer, sector of the economy, industry or the market as a whole. Investments in small- and mid-cap companies involve risks and volatility and possible illiquidity greater than investments in larger, more established companies. Foreign investments subject the Fund to political, economic, market, social and other risks within a particular country, as well as to potential currency instabilities and less stringent financial and accounting standards generally applicable to U.S. issuers. Risks are enhanced for emerging market issuers. The Fund may invest significantly in issuers within a particular sector, which may be negatively affected by market, economic or other conditions, making the Fund more vulnerable to unfavorable developments in the sector.

Columbia Acorn Fund Class Z shares gained 2.54% in the second quarter of 2015, outperforming the Fund's primary benchmark, the Russell 2500 Index, which declined by 0.34% during the period. For the six months ended June 30, the Fund rose by 6.61%, topping the 4.81% gain by the Russell 2500 Index. Good stock selection in the health care sector, and specifically in biotech-related names, represented about two-thirds of the outperformance during the second quarter. Most of the remaining outperformance relative to the benchmark resulted from good stock selection in the financials sector.

Within health care, the "orphan drug" investment theme came to fruition with Alexion's takeover of Synageva BioPharma at a 128% premium to pre-announcement trading levels. Returning 109% during the quarter and 119% for the first half of the year, Synageva was at the core of the investment theme begun in 2007 to invest in companies developing drugs to treat "orphan" diseases—serious ailments that affect small numbers of people—which benefit from a favorable regulatory approval process. Orphan drug developers Ultragenyx Pharmaceutical (up 65% for the quarter) and Sarepta Therapeutics (up 129%), as well as biotech Seattle Genetics (up 37%), all rose on the Synageva take-out offer and accounted for most of the rest of the Fund's outperformance in health care. For the year-to-date period, these stocks had gains of 135%, 110% and 51%, respectively. We believe the results achieved within our orphan drug theme offer a good example of how our research structure and investment process can deliver unique value for Fund investors over the long term.

Within financials, investment manager SEI Investments led the outperformance, gaining 12% in the second quarter and 23% year to date. The company's actively managed investment strategies continued to attract strong net cash inflows. The Fund also benefited from a takeover offer for HCC Insurance, which rose 36% and was sold during the quarter.

Fund industrial stocks fell 1.6% in the second quarter, outperforming a 2.5% decline for the industrial sector within the benchmark. However, the Fund's overweight position resulted in a larger negative impact versus the benchmark's much smaller weighting in the sector. Notable detractors for the Fund included satellite owner Globalstar, down 37% for the quarter and 23% for the half year on regulatory worries about the company's wireless spectrum. Avis Budget Group fell 25% in the quarter and 33% for the half year on investor worries about pricing conditions in the car rental industry. Portable power generator maker Generac declined 18% for the quarter and 15% for the half year following management's lowered 2015 earnings guidance.

Columbia Acorn Fund continued to have significant net redemptions during the first half of 2015, following significant net redemptions during 2014. These redemptions have caused the Fund to realize large amounts of long-term capital gain, as many of the positions liquidated in connection with the redemptions had

appreciated considerably in value during the periods they were held by the Fund. The Fund seeks to minimize the amount of gains distributions affecting its taxable shareholders, consistent with the execution of its investment strategy and the trading activity required by Fund flows. Similarly, CWAM's experienced trading desk makes every effort to minimize the impact of this trading on the prices of Fund portfolio holdings.

Over the past 12 months, and against the backdrop of these Fund net redemptions, we have reduced meaningfully the number of positions owned by the Fund. At June 30, 2015, the Fund had 184 positions, compared to 205 at March 31, 2015, 277 at December 31, 2014, and 320 at June 30, 2014. Our 10 largest positions accounted for 18.5% of Fund assets at quarter end, up slightly from 18.3% at March 31. While past performance is not indicative of future results, the Fund has thrived at this level of concentration in the past. The Fund's holdings may become slightly more concentrated in the future as the result of having fewer overall holdings or more concentration in the largest holdings. Our investment team's key focus going forward is on adding new holdings when valuations are attractive and appropriately sizing the positions the Fund currently owns.

We were comfortable with the Fund's sector positioning versus its benchmark at quarter end. For the reasons described in our first quarter 2015 report, our largest overweight versus the benchmark remained the industrials sector, and our largest underweight remained the financials sector at the second quarter end. During the quarter, the Fund's industrials weight declined by a percentage point, while its financials underweight did not change. The majority of the financials underweight related to the REITs portion of the financials sector.

P. Zachary Egan and Fritz Kaegi joined the management team of Columbia Acorn Fund as co-portfolio managers on May 1, 2015. Mr. Egan has 16 years of industry experience and also serves as President and Chief International Investment Officer of Columbia Wanger, as well as co-portfolio manager of Columbia Acorn International. Mr. Kaegi brings 17 years of industry experience to the Fund and also serves as co-portfolio manager of Columbia Acorn Emerging Markets Fund.

Fund's Positions in Mentioned Holdings

As a percentage of net assets, as of 6/30/15

SEI Investments	2.7	%
Ultragenyx Pharmaceutical	1.5
Generac	0.9
Seattle Genetics	0.7
Avis Budget Group	0.7
Sarepta Therapeutics	0.6
Globalstar	0.6

Fund holdings are as of the date given, are subject to change at any time, and are not recommendations to buy or sell any security. Top holdings exclude short-term holdings and cash, if applicable.

* It is expected that Robert A. Mohn, co-portfolio manager of Columbia Acorn Fund, will step down from this role in the fourth quarter of 2015. Mr. Mohn will continue to perform portfolio management services for the Fund leading up to his departure to ensure a smooth transition in management.

COLUMBIA ACORN® FUND

AT A GLANCE

Total Net Assets of the Fund:
$11.8 billion

Performance data shown below represents past performance, does not guarantee future results, assumes reinvestment of dividends and distributions and does not reflect the deduction of taxes that a shareholder may pay on Fund distributions or the redemption of Fund shares. The investment return and principal value of an investment will fluctuate so that shares, when redeemed, may be worth more or less than their original cost. Current performance may be lower or higher than the performance data shown. Performance data reflects fee waivers or reimbursements of Fund expenses, if any; in their absence, performance results would have been lower. Indexes are unmanaged; their results do not reflect the effect of expenses or sales charges. Securities in the Fund may not match those in an index. Please visit columbiathreadneedle.com/us for performance data current to the most recent month-end.

The Growth of a $10,000 Investment in Columbia Acorn® Fund Class Z Shares

June 10, 1970 (Fund inception) through June 30, 2015

This chart shows the change in value of a hypothetical $10,000 investment in Class Z shares of the Fund during the stated time period. A $10,000 investment in Columbia Acorn Fund at inception appreciated to $31,777 on December 31, 1978, the inception date of the Russell 2500 Index. For comparison with the Russell 2500 Index, we assigned the index the same value as the Fund at index inception. Although the Fund typically invests in small- and mid-sized companies, the comparison to the S&P 500 Index is presented to show performance against a widely recognized market index over the life of the Fund.

Average Annual Total Returns for period ended June 30, 2015

	2nd quarter			Year to date			1 year			5 years			10 years			Life of Fund
Class Z (6/10/70 inception)		2.54	%		6.61	%		4.73	%		15.55	%		8.79	%		14.58	%
Class A (10/16/00 inception)
without sales charge		2.46			6.45			4.45			15.21			8.48			14.21
with sales charge		-3.43			0.32			-1.56			13.85			7.83			14.06
Russell 2500 Index*		-0.34			4.81			5.92			17.85			9.09			N/A

Results for other share classes can be found on Page 2.

*The Fund's primary benchmark. Please see Page 126 for index descriptions.

Returns for Class A shown with and without the maximum initial sales charge of 5.75%. As stated in the May 1, 2015, prospectus, the Fund's annual operating expense ratio is 0.79% for Class Z shares and 1.08% for Class A shares. The returns shown for periods prior to the inception of the Fund's Class A shares append the returns of the Fund's Class Z shares, the Fund's oldest share class. These returns are adjusted to reflect any higher class-related operating expenses of the newer share classes, as applicable. Please visit columbiathreadneedleus.com/investment-products/mutual-funds/appended-performance for more information.

Portfolio Diversification

as a percentage of net assets, as of 6/30/15

Top 10 Holdings

as a percentage of net assets, as of 6/30/15

1.	SEI Investments Mutual Fund Administration & Investment Management	2.7	%
2.	Donaldson Industrial Air Filtration	2.4	%
3.	Ametek Aerospace/Industrial Instruments	2.1	%
4.	Cepheid Molecular Diagnostics	2.1	%
5.	LKQ Alternative Auto Parts Distribution	1.7	%
6.	Amphenol Electronic Connectors	1.7	%
7.	Mettler-Toledo International Laboratory Equipment	1.5	%
8.	Ultragenyx Pharmaceutical Biotech Focused on "Ultra-Orphan" Drugs	1.5	%
9.	Nordson Dispensing Systems for Adhesives & Coatings	1.4	%
10.	Associated Banc-Corp Midwest Bank	1.4	%

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

COLUMBIA ACORN INTERNATIONAL®

IN A NUTSHELL


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

Market risk may affect a single issuer, sector of the economy, industry or the market as a whole. International investing involves certain risks and volatility due to potential political, economic or currency instabilities and different, potentially less stringent, financial and accounting standards than those generally applicable to U.S. issuers. Risks are enhanced for emerging market issuers. Investments in small- and mid-cap companies involve risks and volatility and possible illiquidity greater than investments in larger, more established companies. Please also see "A Comment on Trading Volumes" on Page 1 of this report.

Columbia Acorn International Class Z shares gained 0.81% in the second quarter of 2015, bringing its year-to-date return to 5.18%. This was 2.79% behind the Fund's primary benchmark, the S&P Global ex-U.S. Between $500M and $5B® Index, which rose 7.97% year to date.

The majority of the Fund's underperformance for the half year was the result of weak relative performance in Asia, excluding Japan, which comprised roughly 27% of both the Fund and the benchmark. The strong rally in Chinese domestic shares (described in more detail below) helped lift China-related shares listed in Hong Kong in the benchmark nearly 25%, and the Fund's China-related holdings did not keep pace. In Hong Kong itself, Fund holdings continued to be negatively impacted by weak domestic demand in consumer stocks, as well as the continued decline in the Macau gaming sector. Elsewhere in Asia, underperformance in Korea was primarily due to the Fund's lack of holdings in the health care sector, which rallied over 100% on positive news regarding drug approvals. On the upside, in Japan, where the Fund's weight roughly matched that of the benchmark, good stock selection helped Fund stocks outperform the benchmark during the first half of 2015.

Although the principal Chinese stock exchanges in Shanghai and Shenzen are by regulation inaccessible to most non-Chinese investors, including the Fund, this so-called "A-share market" is the world's second largest equity market, calculated in U.S. dollars.* In the 12 months ended June 30, 2015, the Shanghai A and Shenzen A share indexes rose 109% and 125%, respectively, inclusive of a major correction in June. The rally has captured the imagination of millions of new domestic Chinese investors who have rushed to open brokerage accounts and speculate in the market. Margin lending reached record highs in June, representing an estimated 12% of the free-float market capitalization of marginable stocks, according to Reuters. The launch in November 2014 of the "Shanghai-Hong Kong Connect," a partnership between the Hong Kong and Shanghai exchanges that allows traders registered on each exchange to invest in stocks on the other, was thought to be the global investors' gateway into the China A-share market. In fact, it has resulted to date in large amounts of money flowing from Chinese investors into shares listed on the Hong Kong exchange, significantly bolstering that market.

Given this market environment, Columbia Acorn International's underweight in China-related shares has hurt relative performance, but we have been skeptical of the hype around the Shanghai-Hong Kong Connect and the rapid rise in speculation by Chinese investors, which we believe warrant caution for global investors like the Fund. We continue to be cautious about allocating capital in the region, although we have recently initiated some new positions there, as discussed below. The Chinese political leadership has been engaged for some time in a very public

project to transform its large economy from one that has been almost solely export-oriented and investment-led, into one more focused on its internal market and meeting the needs of the Chinese consumer and citizen. This re-orientation is necessitated by an economic growth imperative in light of industrial capacity overinvestment and increasing demands for an enhanced quality of life. In recent months, some elements of a policy framework designed to address these goals have become clearer, which we believe create some attractive opportunities for long-term investors like the Fund. In particular, we like the prospects for entrepreneurial Chinese companies focused on health care, certain types of infrastructure development, and meeting the goals of evolving environmental regulation.

Consistent with this view, we have recently increased the Fund's exposure to China, although it remains slightly underweight compared to the benchmark. We initiated positions in China Everbright International, a municipal waste-to-energy operating facility, and SIIC Environment, a municipal water treatment operator, both of which will benefit from efforts to clean up a highly polluted environment after years of heavy industrial growth. Another new position, Phoenix Healthcare Group, has been winning contracts to manage public hospitals, and through modern organizational and information systems, it is increasing health care delivery standards while turning around loss-making, former state-managed operations. At June 30, the Fund's exposure to China (through Hong Kong-listed, Singapore-listed and U.S.-listed shares) was approximately 6%, compared to 3% at December 31, 2014.

During the first half of 2015, there was significant world focus and dramatic headlines about the potential exit of Greece from the eurozone and the possible impact. While a Greek exit from the common euro currency cannot be ruled out, we think that it is an unlikely outcome and one that entails little contagion risk for the rest of Europe because of the way the debt is held. Whatever the outcome, we do not believe it would portend a broader dissolution of the eurozone. Consequently, we have not modified the Fund's portfolio to anticipate this scenario. We remain overweight in Europe relative to the benchmark by approximately three percentage points.

*Data source: the World Federation of Exchanges.

Fund's Positions in Mentioned Holdings

As a percentage of net assets, as of 6/30/15

China Everbright International	0.7	%
SIIC Environment	0.3
Phoenix Healthcare Group	0.3

Fund holdings are as of the date given, are subject to change at any time, and are not recommendations to buy or sell any security. Top holdings exclude short-term holdings and cash, if applicable.

COLUMBIA ACORN INTERNATIONAL®

AT A GLANCE

Total Net Assets of the Fund:
$7.9 billion

The Growth of a $10,000 Investment in Columbia Acorn International® Class Z Shares

September 23, 1992 (Fund inception) through June 30, 2015

This chart shows the change in value of a hypothetical $10,000 investment in Class Z shares of the Fund during the stated time period.

Average Annual Total Returns for period ended June 30, 2015

	2nd quarter			Year to date			1 year			5 years			10 years			Life of Fund
Class Z (9/23/92 inception)		0.81	%		5.18	%		-5.02	%		10.57	%		9.19	%		10.87	%
Class A (10/16/00 inception)
without sales charge		0.74			5.05			-5.29			10.21			8.82			10.46
with sales charge		-5.05			-0.99			-10.74			8.91			8.18			10.17
S&P Global Ex-U.S. Between $500M and $5B® Index*		2.91			7.97			-1.52			9.91			8.20			8.48

Results for other share classes can be found on Page 2.

*The Fund's primary benchmark. Please see Page 126 for index descriptions.

Returns for Class A shown with and without the maximum initial sales charge of 5.75%. As stated in the May 1, 2015, prospectus, the Fund's annual operating expense ratio is 0.93% for Class Z shares and 1.26% for Class A shares. The returns shown for periods prior to the inception of the Fund's Class A shares append the returns of the Fund's Class Z shares, the Fund's oldest share class. These returns are adjusted to reflect any higher class-related operating expenses of the newer share classes, as applicable. Please visit columbiathreadneedleus.com/investment-products/mutual-funds/appended-performance for more information.

Portfolio Diversification

as a percentage of net assets, as of 6/30/15

Top 10 Holdings

as a percentage of net assets, as of 6/30/15

1.	Coronation Fund Managers (South Africa) South African Fund Manager	1.2	%
2.	CCL Industries (Canada) Global Label Converter	1.0	%
3.	Zee Entertainment Enterprises (India) Indian Programmer of Pay Television Content	1.0	%
4.	Distribuidora Internacional de Alimentación (Spain) Discount Retailer in Spain & Latin America	1.0	%
5.	SimCorp (Denmark) Software for Investment Managers	1.0	%
6.	Spotless (Australia) Facility Management & Catering Company	1.0	%
7.	Spirax Sarco (United Kingdom) Steam Systems for Manufacturing & Process Industries	0.8	%
8.	President Chain Store (Taiwan) Convenience Chain Store Operator in Taiwan	0.8	%
9.	Singapore Exchange (Singapore) Singapore Equity & Derivatives Market Operator	0.8	%
10.	Partners Group (Switzerland) Private Markets Asset Management	0.8	%

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.

COLUMBIA ACORN USA®

IN A NUTSHELL


Robert A. Mohn* Co-Portfolio Manager				William J. Doyle* Co-Portfolio Manager

Columbia Acorn USA Class Z shares gained 2.02% in the second quarter of 2015, outperforming the Fund's primary benchmark, the Russell 2000 Index, which rose 0.42%. Year to date through June 30, the Fund was up 7.25%, well ahead of the 4.75% gain of its benchmark. Strong performance in the health care sector, particularly in biotech stocks, fueled the Fund's strong relative performance for both periods.

Four of the top five contributors to Fund performance in the second quarter were biotech names. Three of these four biotech winners develop drugs to fight orphan diseases—rare diseases that affect a small percentage of the population. Focusing on orphan drug companies has been one of the Fund's investment themes. Synageva BioPharma gained 109% in the quarter on news it was being acquired by Alexion Pharmaceuticals. For the half-year period, Synageva was up 120%. We sold the Fund's position in the stock during the quarter to capture its strong gains. Ultragenyx Pharmaceutical saw its stock rise on Synageva's announcement and on news of positive test results for an orphan drug in its pipeline. Ultragenyx gained 64% in the quarter and was up 137% for the half year. Sarepta Therapeutics, up 129% in the quarter and 110% for the half year, also bounced on the Synageva news and on a favorable review from the FDA of its drug to treat Duchenne muscular dystrophy. Our remaining biotech winner was Seattle Genetics, a developer of antibody-based therapies for cancer, which gained 37% in the quarter and ended the half year up 51%, as its stock benefited from strength in the sector.

Other winners in the quarter included Texas thrift LegacyTexas, which gained 34% as concerns over its energy loan book abated. Virtusa, a provider of offshore IT outsourcing services, rose 24% in the quarter on strong revenue growth fueled by demand from financial services clients.

Rental car companies Hertz and Avis Budget Group slumped in the quarter, falling 16% and 25%, respectively, as rental car pricing year over year grew less than Wall Street analysts believed it would. We are comfortable with the rate of pricing growth. With a 34% loss for Avis Budget Group and a 27% decline for Hertz, these stocks were the Fund's biggest detractors for the six-month period.

The Fund also experienced some declines in the industrial sector. Generac, a manufacturer of standby power generators, had weak year-over-year sales, as electrical power outages fell well below trend. Generac's stock dropped 18% in the quarter and was off 15% year to date. Oshkosh, a specialty truck manufacturer, was added to the Fund in the second quarter but got off to a bumpy start. Its 22% decline followed the company's release of weak

revenue guidance within its aerial work platform business segment. A provider of international container leases, CAI International fell 16% in the second quarter as sharp declines in steel prices have lowered the cost of buying ocean going container boxes, and lower box prices have translated into falling daily rental rates for CAI's fleet.

We are encouraged by Columbia Acorn USA's performance to date in 2015 and with the progress being made in the Fund's longer term results. For the one-year period ended June 30, 2015, Columbia Acorn USA's 8.21% gain was 1.72% ahead of its benchmark, and Fund results for the five- and 10-year periods were less than a percentage point off the benchmark. This quarter we also saw our orphan drug biotech theme come to fruition. Orphan pharmaceutical Synageva BioPharma, for example, was added to the Fund in the first quarter of 2012 and the position produced a cumulative gain within Columbia Acorn USA of 574% upon its sale in the second quarter. After the biotech group's multi-year run-up, we believe that the sector's valuations appear stretched. With the removal of Synageva BioPharma from the portfolio and some selective trimming of other positions, we have recently reduced the Fund's exposure to this area.

Fund's Positions in Mentioned Holdings

As a percentage of net assets, as of 6/30/15

Ultragenyx Pharmaceutical	1.5	%
Avis Budget Group	1.4
Sarepta Therapeutics	1.0
LegacyTexas	1.0
Virtusa	0.9
Generac	0.9
CAI International	0.8
Hertz	0.7
Seattle Genetics	0.7
Oshkosh	0.5

Fund holdings are as of the date given, are subject to change at any time, and are not recommendations to buy or sell any security. Top holdings exclude short-term holdings and cash, if applicable.

* It is expected that Robert A. Mohn, co-portfolio manager of Columbia Acorn USA, will step down in the fourth quarter of 2015. William J. Doyle, current co-portfolio manager of Columbia Acorn USA, will continue in that role. Mr. Mohn will continue to perform portfolio management services for the Fund leading up to his departure to ensure a smooth transition in management.

COLUMBIA ACORN USA®

AT A GLANCE

Total Net Assets of the Fund:
$1.3 billion

The Growth of a $10,000 Investment in Columbia Acorn USA® Class Z Shares

September 4, 1996 (Fund inception) through June 30, 2015

This chart shows the change in value of a hypothetical $10,000 investment in Class Z shares of the Fund during the stated time period.

Average Annual Total Returns for period ended June 30, 2015

	2nd quarter			Year to date			1 year			5 years			10 years			Life of Fund
Class Z (9/4/96 inception)		2.02	%		7.25	%		8.21	%		16.98	%		7.80	%		10.93	%
Class A (10/16/00 inception)
without sales charge		1.96			7.14			7.96			16.67			7.50			10.56
with sales charge		-3.91			0.97			1.74			15.30			6.87			10.21
Russell 2000 Index*		0.42			4.75			6.49			17.08			8.40			8.72

Results for other share classes can be found on Page 2.

*The Fund's primary benchmark. Please see Page 126 for index descriptions.

Returns for Class A shown with and without the maximum initial sales charge of 5.75%. As stated in the May 1, 2015, prospectus, the Fund's annual operating expense ratio is 1.08% for Class Z shares and 1.34% for Class A shares. The returns shown for periods prior to the inception of the Fund's Class A shares append the returns of the Fund's Class Z shares, the Fund's oldest share class. These returns are adjusted to reflect any higher class-related operating expenses of the newer share classes, as applicable. Please visit columbiathreadneedleus.com/investment-products/mutual-funds/appended-performance for more information.

Portfolio Diversification

as a percentage of net assets, as of 6/30/15

Top 10 Holdings

as a percentage of net assets, as of 6/30/15

1.	Ametek Aerospace/Industrial Instruments	3.3	%
2.	Nordson Dispensing Systems for Adhesives & Coatings	3.1	%
3.	Mettler-Toledo International Laboratory Equipment	3.1	%
4.	Extra Space Storage Self Storage Facilities	2.9	%
5.	HEICO FAA-approved Aircraft Replacement Parts	2.8	%
6.	Donaldson Industrial Air Filtration	2.6	%
7.	IPG Photonics Fiber Lasers	2.5	%
8.	Cepheid Molecular Diagnostics	2.1	%
9.	Drew Industries RV & Manufactured Home Components	1.7	%
10.	Ansys Simulation Software for Engineers & Designers	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.

COLUMBIA ACORN INTERNATIONAL SELECT^SM

IN A NUTSHELL


Christopher J. Olson Co-Portfolio Manager				Andreas Waldburg-Wolfegg Co-Portfolio Manager

Market risk may affect a single issuer, sector of the economy, industry or the market as a whole. Foreign investments subject the Fund to political, economic, market, social and other risks within a particular country, as well as to potential currency instabilities and less stringent financial and accounting standards generally applicable to U.S. issuers. Risks are enhanced for emerging market issuers. Investments in small- and mid-cap companies involve risks and volatility and possible illiquidity greater than investments in larger, more established companies. The Fund may invest significantly in issuers within a particular sector, which may be negatively affected by market, economic or other conditions, making the Fund more vulnerable to unfavorable developments in the sector. Please also see "A Comment on Trading Volumes" on Page 1 of this report.

Columbia Acorn International Select Class Z shares ended the second quarter of 2015 up 2.37%, topping the 2.27% gain of the Fund's primary benchmark, the S&P Developed Ex-U.S. Between $2B and $10B® Index. For the six-month period ended June 30, the Fund was up 3.88% while the benchmark gained 8.00% for the same period. On a sector basis, Fund industrials outperformed relative to the benchmark for both periods, while materials and financials negatively impacted performance. On a regional basis, good stock selection in Asia, excluding Japan, was a positive during the quarter. Columbia Acorn International Select also outperformed in the UK and Ireland in the second quarter, though a lesser weighting than the benchmark diminished its impact relative to the index.

The top contributor to Fund performance in the second quarter and for the half year period was CJ Corp, a holding company of Korean consumer conglomerates. Up 66% in the quarter and 86% for the half, investors responded favorably to the company's new management and its successful implementation of restructuring programs. In the United Kingdom, WH Smith, a newsprint, book and stationery retailer, gained 24% in the second quarter, benefiting from strong air passenger demand in its travel division. WH Smith was added to the portfolio in the first quarter and, at the second quarter end, was up 15%. Silver and gold miner Tahoe Resources rebounded in the second quarter, gaining 11% after a weak first quarter left the stock looking inexpensive. Tahoe's strong quarter was not enough to overcome earlier weakness, however, leaving its stock with a 12% loss for the half year. CCL Industries, a global label converter based in Canada, gained 10% in the second quarter and was up 14% for the half year period on continued strong revenue growth.

In Japan, Japan Tobacco, a maker of cigarettes, had another strong quarter, gaining 14% as investor fears surrounding its Russian operations abated and management undertook a stock buyback. Japan Tobacco's stock was up 30% for the semiannual period. KDDI, a mobile and fixed line communication service provider in Japan, gained 7% in the quarter and was up 16% for the half year, as it has continued to deliver consistent earnings growth driven by higher average revenue per user and by subscriber growth.

The biggest detractor from gains in the quarter and half was Coronation Fund Managers, a South African fund manager. Down 15% in the quarter and 31% year to date, its stock suffered from significantly lower performance fees compared to those earned last year. Beadell Resources, a gold miner operating in Brazil, and Goldcorp, a Canadian

gold miner, were also among the detractors. Beadell fell 26% in the quarter and was off 18% for the half-year period, while Goldcorp declined 10% in the quarter and ended the half down 11%. Both were affected by weak gold prices. Park24, a parking lot operator in Japan, gained nearly 40% in the first quarter as investors migrated toward more stable domestic businesses, but the second quarter took away some of that gain, as its stock fell 17% on a weaker than expected recovery in parking lot demand. Park24 returned 16% year to date. Nippon Prologis REIT, a logistics REIT in Japan, was down 15% for the second quarter and the half year as investors rotated into other sectors after several years of outperformance.

Andreas Waldburg-Wolfegg was named co-portfolio manager of Columbia Acorn International Select, effective May 1, 2015. Mr. Waldburg-Wolfegg brings 22 years of industry experience to the portfolio and also serves as co-portfolio manager of Columbia Acorn European Fund.

Fund's Positions in Mentioned Holdings

As a percentage of net assets, as of 6/30/15

KDDI	3.9	%
Tahoe Resources	3.2
CJ Corp	3.1
CCL Industries	2.8
Japan Tobacco	2.5
WH Smith	2.5
Coronation Fund Managers	2.0
Goldcorp	1.9
Nippon Prologis REIT	1.3
Park24	1.0
Beadell Resources	0.8

Fund holdings are as of the date given, are subject to change at any time, and are not recommendations to buy or sell any security. Top holdings exclude short-term holdings and cash, if applicable.

COLUMBIA ACORN INTERNATIONAL SELECT^SM

AT A GLANCE

Total Net Assets of the Fund:
$223.4 million

The Growth of a $10,000 Investment in Columbia Acorn International Select^SM Class Z Shares

November 23, 1998 (Fund inception) through June 30, 2015

This chart shows the change in value of a hypothetical $10,000 investment in Class Z shares of the Fund during the stated time period.

Average Annual Total Returns for period ended June 30, 2015

	2nd quarter			Year to date			1 year			5 years			10 years			Life of Fund
Class Z (11/23/98 inception)		2.37	%		3.88	%		-11.76	%		9.21	%		8.11	%		8.77	%
Class A (10/16/00 inception)
without sales charge		2.26			3.70			-12.04			8.86			7.76			8.41
with sales charge		-3.60			-2.24			-17.09			7.58			7.12			8.03
S&P Developed Ex-U.S. Between $2B and $10B® Index*		2.27			8.00			-1.35			10.68			6.99			7.68

Results for other share classes can be found on Page 2.

*The Fund's primary benchmark. Please see Page 126 for index descriptions.

Returns for Class A shown with and without the maximum initial sales charge of 5.75%. As stated in the May 1, 2015, prospectus, the Fund's annual operating expense ratio is 1.18% for Class Z shares and 1.47% for Class A shares. The returns shown for periods prior to the inception of the Fund's Class A shares append the returns of the Fund's Class Z shares, the Fund's oldest share class. These returns are adjusted to reflect any higher class-related operating expenses of the newer share classes, as applicable. Please visit columbiathreadneedleus.com/investment-products/mutual-funds/appended-performance for more information.

Portfolio Diversification

as a percentage of net assets, as of 6/30/15

Top 10 Holdings

as a percentage of net assets, as of 6/30/15

1.	Naspers (South Africa) Media in Africa, China, Russia & other Emerging Markets	4.3	%
2.	CapitaLand Mall Trust (Singapore) Singapore Commercial Property Real Estate Investment Trust	4.2	%
3.	Singapore Exchange (Singapore) Singapore Equity & Derivatives Market Operator	4.1	%
4.	KDDI (Japan) Mobile & Fixed Line Communication Service Provider in Japan	3.9	%
5.	Recruit Holdings (Japan) Recruitment & Media Services	3.6	%
6.	Secom (Japan) Security Services	3.5	%
7.	Tahoe Resources (Guatemala) Silver & Gold Projects in Guatemala & Peru	3.2	%
8.	CJ Corp (Korea) Holding Company of Korean Consumer Conglomerate	3.1	%
9.	Partners Group (Switzerland) Private Markets Asset Management	2.8	%
10.	CCL Industries (Canada) Global Label Converter	2.8	%

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.

COLUMBIA ACORN SELECT^SM

IN A NUTSHELL


Robert A. Chalupnik Lead Portfolio Manager				Matthew S. Szafranski Co-Portfolio Manager

Market risk may affect a single issuer, sector of the economy, industry or the market as a whole. Investments in small- and mid-cap companies involve risks and volatility and possible illiquidity greater than investments in larger, more established companies. Foreign investments subject the Fund to risks, including political, economic, market, social and other risks, within a particular country, as well as to potential currency instabilities and less stringent financial and accounting standards generally applicable to U.S. issuers. Risks are enhanced for emerging market issuers. The Fund may invest significantly in issuers within a particular sector, which may be negatively affected by market, economic or other conditions, making the Fund more vulnerable to unfavorable developments in the sector.

Columbia Acorn Select Class Z shares ended the second quarter of 2015 up 3.16%, outperforming the 1.06% decline of its primary benchmark, the S&P MidCap 400 Index. For the six months ended June 30, the Fund was up 6.07% versus a 4.20% gain for the benchmark. Solid performance from Fund health care stocks, specifically biotech-related names, contributed to the Fund's outperformance for both periods. Being underweight in utilities also benefited the Fund, as this group was down nearly 7% for the quarter and 12% year to date in the benchmark. We have not held any utility stocks during the past year due to high valuations for these low-growth companies.

Synageva BioPharma, a biotech company focused on orphan diseases, surged 110% in the quarter after announcing that the company was being acquired by Alexion Pharmaceuticals. For the half year, the stock was up nearly 121%. We chose to sell this position on the positive news. Ultragenyx Pharmaceutical is also focused on drugs that treat very rare diseases. Its stock was up nearly 64%, as the sector bounced with Synageva. Ultragenyx also benefited from favorable news for several of its pipeline drugs. For the half year, Ultragenyx was up nearly 109%.

Other winners included LKQ, a distributor of alternative auto parts for the collision industry. Up 18% in the quarter and 7% for the half year, LKQ enjoyed sales growth across all of its business segments and also benefited from a rebound in margins after a tough fourth quarter. SEI Investments, a mutual fund administrator and investment manager, gained 12% in the quarter and 23% for the half year, as its actively managed investment strategies attracted strong cash inflows.

In addition to Synageva BioPharma, the issuers of two other Fund positions announced that they were being sold during the second quarter. Pall, a life science and industrial filtration company, gained 22% in the quarter following the news that it was being acquired by Danaher. Pall's stock was up 21% for the half year. Informatica, an enterprise data integration software company, was the third acquisition. Informatica's stock was up only 9% in the quarter, as much of the 25% year-to-date gain was realized earlier in the year when news broke that the company had hired an investment banker to contact potential buyers. We sold out of both positions following the announcements.

On the downside, several Fund consumer stocks declined in the second quarter. The Fresh Market, a specialty food retailer, was off over 20% for the quarter and the half year. While earnings were slightly above industry estimates, comparative quarterly sales data missed expectations. An unusually large number of competitive store openings have

hurt the company's overall sales, but we expect this trend to normalize. Fossil, a manufacturer of watches and jewelry, was down nearly 16% in the quarter and 14% for the half. A decline in North American sales of Fossil's Michael Kors line, and buzz around the Apple Watch and other wearable technology, negatively impacted returns. United Natural Foods, a distributor of natural/organic foods to grocery stores, was off 17% for the quarter and 18% for the half year as the specialty grocery industry experienced a general slowdown early in the year.

Other laggards included Solera Holdings, a developer of software for the automotive insurance claims processing industry, which fell 13% in the second quarter and ended the half year down 9%. With 60% of its sales outside of the United States, currency headwinds played a role in Solera's decline. Donaldson, an air filtration company, fell 5% in the quarter and was off over 6% for the half year. As mentioned last quarter, the company has suffered from weaker sales to its agriculture end market and has also been impacted by the strong U.S. dollar.

After several years of no take-out activity in the Fund, Columbia Acorn Select had three in the quarter and four so far in 2015. Acquisitions of Fund holdings have benefited the Fund historically, and typically confirm the investment merit of the business.

Our strategy remains unchanged. We continue to invest in growing businesses that trade at what we believe to be reasonable valuations relative to the quality and fundamentals of the business.

Matthew S. Szafranski was named co-portfolio manager of Columbia Acorn Select on May 1, 2015. As an analyst, Mr. Szafranski covers leisure, lodging, gaming, restaurants and consumer staples companies for our domestic team.

Fund's Positions in Mentioned Holdings

As a percentage of net assets, as of 6/30/15

Donaldson	5.0	%
LKQ	5.0
SEI Investments	4.6
The Fresh Market	3.6
Solera Holdings	2.6
Fossil	2.0
United Natural Foods	1.4
Ultragenyx Pharmaceutical	1.4

Fund holdings are as of the date given, are subject to change at any time, and are not recommendations to buy or sell any security. Top holdings exclude short-term holdings and cash, if applicable.

COLUMBIA ACORN SELECT^SM

AT A GLANCE

Total Net Assets of the Fund:
$604.7 million

The Growth of a $10,000 Investment in Columbia Acorn Select^SM Class Z Shares

November 23, 1998 (Fund inception) through June 30, 2015

This chart shows the change in value of a hypothetical $10,000 investment in Class Z shares of the Fund during the stated time period.

Average Annual Total Returns for period ended June 30, 2015

	2nd quarter			Year to date			1 year			5 years			10 years			Life of Fund
Class Z (11/23/98 inception)		3.16	%		6.07	%		7.25	%		13.01	%		7.98	%		10.35	%
Class A (10/16/00 inception)
without sales charge		3.12			5.96			6.96			12.69			7.67			10.01
with sales charge		-2.82			-0.12			0.80			11.36			7.04			9.62
S&P MidCap 400® Index*		-1.06			4.20			6.40			17.82			9.74			10.55

Results for other share classes can be found on Page 2.

*The Fund's primary benchmark. Please see Page 126 for index descriptions.

Returns for Class A shown with and without the maximum initial sales charge of 5.75%. As stated in the May 1, 2015, prospectus, the Fund's annual operating expense ratio is 0.84% for Class Z shares and 1.12% for Class A shares. The returns shown for periods prior to the inception of the Fund's Class A shares append the returns of the Fund's Class Z shares, the Fund's oldest share class. These returns are adjusted to reflect any higher class-related operating expenses of the newer share classes, as applicable. Please visit columbiathreadneedleus.com/investment-products/mutual-funds/appended-performance for more information.

Portfolio Diversification

as a percentage of net assets, as of 6/30/15

Top 10 Holdings

as a percentage of net assets, as of 6/30/15

1.	Ametek Aerospace/Industrial Instruments	6.4	%
2.	Donaldson Industrial Air Filtration	5.0	%
3.	LKQ Alternative Auto Parts Distribution	5.0	%
4.	SEI Investments Mutual Fund Administration & Investment Management	4.6	%
5.	The Fresh Market Specialty Food Retailer	3.6	%
6.	Vail Resorts Ski Resort Operator & Developer	3.2	%
7.	Associated Banc-Corp Midwest Bank	3.1	%
8.	Nordson Dispensing Systems for Adhesives & Coatings	3.0	%
9.	Airgas Industrial Gas Distributor	2.9	%
10.	Gentex Manufacturer of Auto Parts	2.8	%

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.

COLUMBIA THERMOSTAT FUND^SM

IN A NUTSHELL


Charles P. McQuaid Lead Portfolio Manager				Christopher J. Olson Co-Portfolio Manager

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

The value of an investment in the Fund is based primarily on the performance of the underlying funds in which it invests. The Fund is subject to the risk that the investment manager's decisions regarding asset classes and underlying funds will not anticipate market trends successfully, resulting in a failure to preserve capital or lower total return. The Investment Manager may prefer an underlying fund in the Columbia Acorn Family of Funds over alternative investments. There can be no assurance that the Columbia Acorn Funds will outperform similar funds managed by the Investment Manager's affiliates. This is not an offer of the shares of any other mutual fund mentioned herein.

Our fund of funds, Columbia Thermostat Fund, saw its Class Z shares drop 0.26% in the second quarter of 2015. This compares to a 0.28% quarterly gain of the Fund's primary equity benchmark, the S&P 500® Index. The Fund's primary debt benchmark, the Barclays U.S. Aggregate Bond Index, fell 1.68% in the quarter, and the 50/50 Blended Benchmark was off 0.70% for the same period. For the half year, the Fund's 1.23% gain matched the S&P 500 Index, outpaced its Barclay's benchmark, which was off 0.10%, and topped the 0.66% gain of the 50/50 Blended Benchmark.

The weighted average gain for the Fund's equity portfolio was 1.02% for the second quarter, led by the performance of Columbia Acorn Select, up 3.19%. For the six months through June 30, the weighted average equity gain was 3.65%, led by the 8.35% gain of Columbia Select Large Cap Growth Fund. For both periods, five of seven of Thermostat's stock funds beat the S&P 500, and four beat their own benchmarks.

The bond portion of the Fund had a weighted average loss in the second quarter, falling 0.34%. Columbia Intermediate Bond Fund was the biggest detractor, falling 1.61% in the quarter. Year to date, the bond portfolio had a weighted average gain of 1.15%, due largely to the 2.69% gain of Columbia Income Opportunities Fund. During both periods, all four bond funds beat the Barclay's benchmark and beat or nearly matched their own benchmarks.

As mentioned last quarter, as a result of the periodic review called for by Columbia Thermostat's prospectus, we made several changes that went into effect May 1, 2015. On the equity side, we decreased the Fund's weighting in Columbia Acorn Fund and increased its weight in Columbia Contrarian Core Fund. On the bond side, we decreased exposure to Columbia Intermediate Bond Fund and increased the Fund's weight in Columbia U.S. Government Mortgage Fund. These changes are intended to bring the Fund closer to a market weight in larger cap stocks, and, on the bond side, modestly boost the yield of Thermostat's bond portfolio. We note that over the last several years, we've reduced the weighted average duration of Thermostat's bond portfolio, which should benefit shareholders if interest rates rise.

Also effective May 1, 2015, we revised the stock/bond allocation table. The Fund now moves to 10% stocks at an S&P 500 level over 2,225, up from 2,020. The Fund now moves to 90% stocks at a level of 1,100 or less, up from 970. In between, a 75 point move in the S&P 500 triggers a 5% point change in allocation of stock and bond funds. As a result of this revision, Thermostat increased its equity weight from 10% to 20% and cut its bond weight from 90% to 80% on May 1.

The Fund hit one reallocation trigger in the second quarter following the adoption of the new stock/bond allocation table, increasing stock exposure further, to 25%, and cutting its bond weight to 75% on June 30.

While Thermostat's return was slightly negative in the quarter and modestly positive for the half year, we are pleased with its

performance relative to its benchmarks. Thermostat matched the S&P 500 for the half year while having at most 25% in equities (and that only for the last day of the period) at a time when the bond index was off slightly. This is primarily due to good performance of the underlying funds, discussed above.

Results of the Funds Owned in Columbia Thermostat Fund

as of June 30, 2015

Stock Funds

Fund	Weightings in category			2nd quarter performance			Year to date performance
Columbia Acorn International, Class I		20	%		0.81	%		5.23	%
Columbia Contrarian Core Fund, Class I		20	%*		1.83	%		3.10	%
Columbia Dividend Income Fund, Class I		20	%		-0.82	%		-1.15	%
Columbia Acorn Fund, Class I		10	%*		2.53	%		6.63	%
Columbia Acorn Select, Class I		10	%		3.19	%		6.19	%
Columbia Large Cap Enhanced Core Fund, Class I		10	%		-0.44	%		0.87	%
Columbia Select Large Cap Growth Fund, Class I		10	%		2.48	%		8.35	%
Weighted Average Equity Gain		100	%		1.02	%		3.65	%

Bond Funds

Fund	Weightings in category			2nd quarter performance			Year to date performance
Columbia Short Term Bond Fund, Class I		40	%		0.15	%		0.73	%
Columbia Intermediate Bond Fund, Class I		20	%*		-1.61	%		0.29	%
Columbia Income Opportunities Fund, Class I		20	%		-0.22	%		2.69	%
Columbia U.S. Government Mortgage Fund, Class I		20	%*		0.04	%		1.32	%
Weighted Average Income Gain/Loss		100	%		-0.34	%		1.15	%

* Change effective with the May 1, 2015 prospectus. Weighted average returns through the end of the period reflect linked returns between the previous fund weightings and the current weights in these positions.

Columbia Thermostat Fund Rebalancing in the Second Quarter

May 1, 2015				20% stocks, 80% bonds
June 30, 2015				25% stocks, 75% bonds

The Fund's investments in the underlying funds may present certain risks, including the following. Market risk may affect a single issuer, sector of the economy, industry or the market as a whole. The Fund's investment in other funds subjects it to the investment performance (positive or negative), risks and expenses of these underlying funds. Investments in small- and mid-cap companies involve risks and volatility and possible illiquidity greater than in investments in larger, more established companies. There are risks associated with fixed income investments, including credit risk, market risk, interest rate risk and prepayment and extension risk. In general, bond prices fall when interest rates rise and vice versa. This effect is more pronounced for longer term securities. Non-investment-grade (high-yield or junk) securities present greater price volatility and more risk to principal and income than higher rated securities. Foreign investments subject the Fund to political, economic, market, social and other risks within a particular country, as well as to potential currency instabilities and less stringent financial and accounting standards generally applicable to U.S. issuers. Risks are enhanced for emerging market issuers.

COLUMBIA THERMOSTAT FUND^SM

AT A GLANCE

Total Net Assets of the Fund:
$1.1 billion

The Growth of a $10,000 Investment in Columbia Thermostat Fund^SM Class Z Shares

September 25, 2002 (Fund inception) through June 30, 2015

This chart shows the change in value of a hypothetical $10,000 investment in Class Z shares of the Fund during the stated time period.

Average Annual Total Returns for period ended June 30, 2015

	2nd quarter			Year to date			1 year			5 years			10 years			Life of Fund
Class Z (9/25/02 inception)		-0.26	%		1.23	%		2.69	%		10.78	%		6.53	%		7.77	%
Class A (3/3/03 inception)
without sales charge		-0.33			1.08			2.46			10.51			6.26			7.50
with sales charge		-6.06			-4.75			-3.43			9.22			5.63			7.00
S&P 500® Index*		0.28			1.23			7.42			17.34			7.89			9.72
Barclays U.S. Aggregate Bond Index*		-1.68			-0.10			1.86			3.35			4.44			4.48

Results for other share classes can be found on Page 2.

*The Fund's primary benchmarks. Please see Page 126 for index descriptions.

Returns for Class A shown with and without the maximum initial sales charge of 5.75%. As stated in the May 1, 2015, prospectus, the Fund's annual operating expense ratio is 0.77% for Class Z shares and 1.02% for Class A shares. The returns shown for periods prior to the inception of the Fund's Class A shares append the returns of the Fund's Class Z shares, the Fund's oldest share class. These returns are adjusted to reflect any higher class-related operating expenses of the newer share classes, as applicable. Please visit columbiathreadneedleus.com/investment-products/mutual-funds/appended-performance for more information.

Asset Allocation

as a percentage of net assets, as of 6/30/15

Portfolio Weightings

as a percentage of assets in each investment category, as of 6/30/15

Stock Mutual Funds

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

Bond Mutual Funds

Columbia Short Term Bond Fund, Class I	40	%
Columbia Intermediate Bond Fund, Class I	20	%*
Columbia Income Opportunities Fund, Class I	20	%
Columbia U.S. Government Mortgage Fund, Class I	20	%*

*Change effective with the May 1, 2015 prospectus. Weighted average returns through the end of the period reflect linked returns between the previous fund weightings and the current weights in these positions.

COLUMBIA ACORN EMERGING MARKETS FUND^SM

IN A NUTSHELL


Fritz Kaegi Co-Portfolio Manager				Stephen Kusmierczak Co-Portfolio Manager

Louis J. Mendes Co-Portfolio Manager				Satoshi Matsunaga Co-Portfolio Manager

Market risk may affect a single issuer, sector of the economy, industry or the market as a whole. International investing involves certain risks and volatility due to potential political, economic or currency instabilities and different, potentially less stringent, financial and accounting standards than those generally applicable to U.S. issuers. Risks are enhanced for emerging and frontier market issuers. Investments in small- and mid-cap companies involve risks and volatility and possible illiquidity greater than investments in larger, more established companies. Please also see "A Comment on Trading Volumes" on Page 1 of this report.

Columbia Acorn Emerging Markets Fund Class Z shares lost 2.06% in the second quarter of 2015, underperforming the 1.17% gain of the Fund's primary benchmark, the S&P Emerging Markets Between $500M and $5B® Index. For the first six months of the year, the Fund was down 2.83%, trailing the benchmark's gain of 3.05% by 588 basis points.* Since its inception in August 2011, the Fund has returned an annualized gain of 6.40% compared to the benchmark's 3.68% return, or 272 basis points of outperformance on an annualized basis. The Fund lagged the benchmark in the first half of the year primarily due to the underperformance of Fund stocks with exposure to Southeast Asia and China.

During the quarter and half year, the Fund's main overweight positions underperformed. Southeast Asia, where the Fund had a 21% weight that was seven percentage points over the benchmark, was the worst performing region in the benchmark during the quarter. For most of its existence, Columbia Acorn Emerging Markets Fund has been significantly underweight in China, which was the best performing market in the benchmark in the first half of the year. By the end of June, however, we added about 12 percentage points to the Fund's exposure, as Chinese authorities began to implement market-based policy reforms in certain sectors including environmental protection and health care. While we were skeptical of the high valuations of many China-related stocks, we made several new investments within these sectors at what we believe are reasonable prices. This brought the Fund's exposure to China to slightly over the benchmark weight. Concurrently, many Southeast Asian stocks, which are generally illiquid, were impacted by slower economic growth and tighter liquidity in the region.

The Fund's largest contributor to returns during the second quarter was Chinese tobacco packaging supplier AMVIG Holdings. Its stock gained 15% in the second quarter and was up 31% for the half year, benefiting from the overall Chinese market rally. PChome Online, the only listed e-commerce company in Taiwan, was up 28% in the second quarter and 55% for the half year, as it continued to see strong revenue growth due to Taiwanese consumers' switch to online retail channels. A retail bank and insurer in Kazakhstan, Halyk Savings Bank of Kazakhstan, was up 24% in the quarter as it doubled its dividend and fears about further depreciation of the tenge, Kazakhstan's currency, subsided somewhat. Year to date its stock was up 8%.

The largest percentage decline in the quarter and half year period was Melco Crown (Philippines) Resorts, an operator of an integrated casino resort in the Philippines. Despite a successful grand opening in February, the stock fell 45% in

the quarter and was off 63% for the half year, as market participants seem to fear that negative gaming revenue trends in Macau will spread over Asian casinos. Its stock decline was much sharper than its affiliate Melco International, a Macau casino operator, which declined 36% for the half year and 16% in the second quarter. RFM, the dominant pasta and ice cream manufacturer in the Philippines, was off 22% in the second quarter despite solid first quarter earnings. Its removal from a major index at the end of May seemed to trigger a large sell-off of this small-cap stock. Year to date, RFM was off 17%. Coronation Fund Managers, the leading asset manager in South Africa, fell 14% in the second quarter and declined 30% for the half year due to significantly lower performance fees compared to those earned last year.

Responding to tighter liquidity in local markets, we have been reducing the Fund's overweight in Southeast Asia and, as mentioned, increasing its exposure to China. The stocks we have added with Chinese exposure have unique themes supported by structural tailwinds. We believe that waste treatment companies China Everbright Water and SIIC Environment, for example, should benefit from increased attention in China to environmental issues. Both companies operate in China but are listed in Singapore. We believe that our focus on higher quality businesses that are poised to benefit from positive long-term trends should provide investors with above average risk-adjusted returns.

Satoshi Matsunaga was named co-portfolio manager of Columbia Acorn Emerging Markets Fund, effective May 1, 2015. Mr. Matsunaga has 11 years of industry experience and covers Southeast Asian companies as an analyst. Also effective May 1, P. Zachary Egan is no longer a co-portfolio manager of the Fund.

*A basis point is 1/100 of a percent.

Fund's Positions in Mentioned Holdings

As a percentage of net assets, as of 6/30/15

AMVIG Holdings	3.1	%
Coronation Fund Managers	2.9
Halyk Savings Bank of Kazakhstan - GDR	2.6
PChome Online	1.7
SIIC Environment	1.5
RFM	1.2
Melco Crown (Philippines) Resorts	1.0
China Everbright Water	0.9
Melco International	0.9

Fund holdings are as of the date given, are subject to change at any time, and are not recommendations to buy or sell any security. Top holdings exclude short-term holdings and cash, if applicable.

Columbia Acorn Emerging Markets Fund is closed to most new investors and new accounts with certain exceptions. Refer to the Fund's prospectus for details.

COLUMBIA ACORN EMERGING MARKETS FUND^SM

AT A GLANCE

Total Net Assets of the Fund:
$416.8 million

The Growth of a $10,000 Investment in Columbia Acorn Emerging Markets Fund^SM Class Z Shares

August 19, 2011 (Fund inception) through June 30, 2015

This chart shows the change in value of a hypothetical $10,000 investment in Class Z shares of the Fund during the stated time period.

Average Annual Total Returns for period ended June 30, 2015

	2nd quarter			Year to date			1 year			Life of Fund
Class Z (8/19/11 inception)		-2.06	%		-2.83	%		-9.85	%		6.40	%
Class A (8/19/11 inception)
without sales charge		-2.14			-2.99			-10.09			6.10
with sales charge		-7.77			-8.59			-15.25			4.49
S&P Emerging Markets Between $500M and $5B® Index*		1.17			3.05			-2.71			3.68

Results for other share classes can be found on Page 2.

*The Fund's primary benchmark. Please see Page 126 for index descriptions.

Returns for Class A shown with and without the maximum initial sales charge of 5.75%. As stated in the May 1, 2015, prospectus, the Fund's annual operating expense ratio is 1.33% for Class Z shares and 1.57% for Class A shares.

Portfolio Diversification

as a percentage of net assets, as of 6/30/15

Top 10 Holdings

as a percentage of net assets, as of 6/30/15

1.	Zee Entertainment Enterprises (India) Indian Programmer of Pay Television Content	3.4	%
2.	AMVIG Holdings (China) Chinese Tobacco Packaging Material Supplier	3.1	%
3.	Coronation Fund Managers (South Africa) South African Fund Manager	2.9	%
4.	Halyk Savings Bank of Kazakhstan–GDR (Kazakhstan) Retail Bank & Insurer in Kazakhstan	2.6	%
5.	Koh Young Technology (Korea) Inspection Systems for Printed Circuit Boards	2.1	%
6.	Adani Ports & Special Economic Zone (India) Indian West Coast Shipping Port	2.0	%
7.	Rand Merchant Insurance (South Africa) Directly Sold Property & Casualty Insurance; Holdings in other Insurers	1.9	%
8.	CAR Inc (China) Consolidator of Chinese Auto Rental Sector	1.9	%
9.	Cable and Wireless (United Kingdom) Telecommunications Service Provider in the Caribbean	1.8	%
10.	PChome Online (Taiwan) Taiwanese Internet Retail Company	1.7	%

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

COLUMBIA ACORN EUROPEAN FUND^SM

IN A NUTSHELL


Andreas Waldburg-Wolfegg Co-Portfolio Manager				Stephen Kusmierczak Co-Portfolio Manager

Columbia Acorn European Fund Class Z shares gained 2.30% in the second quarter of 2015, underperforming by 273 basis points* the 5.03% gain of its primary benchmark, the S&P Europe Between $500M and $5B Index. Year to date, the Fund was up 6.80% and trailed the benchmark return of 10.62% by 382 basis points. Since inception, the Fund has delivered an absolute return of 12.61% on an annualized basis, but lagged the benchmark return of 14.88%.

The Fund's largest contributor to performance both in the quarter and for the half year was Cambian, a provider of mental health rehabilitation to adults and children in the United Kingdom. Cambian has demonstrated better outcomes at lower costs based on data-driven protocols, and is a key beneficiary of a government outsourcing effort. The stock gained 37% in the second quarter and was up 50% for the half year. French transport and logistics company Norbert Dentressangle was the next largest contributor in the quarter and half. Its 43% second quarter jump followed a takeout offer and helped drive a 64% year-to-date gain. We sold this long-term holding on the announcement. Ocado, an online grocer in the United Kingdom, gained 35% in the quarter, as the company announced its intention to sign another contract with a traditional grocer for the delivery of its state-of-the-art online grocery system. We believe the company should be a long-term winner as more traditional grocery retail goes online with its better, fresher grocery assortment and lower capital requirements. Year to date, Ocado gained 13%. Denmark's SimCorp, a developer of software for investment managers, saw a continued recovery in new license wins as asset managers responded to new compliance rules introduced following the financial crisis. The stock gained 55% in the half, making it the third largest performance contributor for that period, and gained 23% in the second quarter.

The Fund underperformed in three of its four European regions in the second quarter, with the leading detractors being the Nordic region and Northern and Central Europe. The Mediterranean was the only outperforming region for the Fund, yet also contained the Fund's largest performance detractor, French postage meter equipment company Neopost. Revenues for Neopost have been depressed by weak European demand, while profits from faster-growing new businesses have not offset declines in its core equipment business. Neopost's stock declined over 20% in the quarter and the first half, making it the Fund's biggest detractor for both periods. The second biggest underperformer for both the quarter and half year was UK-based industrial lighting company Dialight. The company announced the departure of its CEO, followed by a profit warning, sending its stock down 28% in the quarter and 35% for the half. The Fund's next two large detractors

were from Scandinavia. Munksjo,^† a Finnish specialty paper maker, declined 14% on little news after reaching a record high at the end of the first quarter. For the half year, its stock was up slightly over 1%. Atea, the largest IT hardware and software reseller and integrator in the Nordic region, dropped 17% in the quarter after the company disclosed that Danish salespeople bribed a regional government official. We believe that the problem is not representative of wider company culture and that reputational damage will be limited. Subsequently, we took advantage of the decline to add to the position. Year to date, Atea was down 10%.

The Fund's underperformance for the half-year period was caused by weak stock picking and was not the result of poor sectoral or geographic positioning versus the benchmark. As bottom-up stock pickers, we do not steer the Fund toward sectors or regions. Our bottom-up approach did, however, result in the Fund having an overweight position in consumer discretionary stocks, which was among the best performing major sectors in the benchmark over the six months. Yet the Fund's gain of 13% in this sector fell short of the benchmark return of 14%. In eight of the 10 industry sectors, stock selection cost the Fund some performance relative to the benchmark during the first half.

*A basis point is 1/100 of a percent.

Fund's Positions in Mentioned Holdings

As a percentage of net assets, as of 6/30/15

Munksjo	3.6	%^†
Neopost	2.1
SimCorp	1.8
Cambian	1.7
Ocado	1.2
Dialight	1.0
Atea	1.0

Fund holdings are as of the date given, are subject to change at any time, and are not recommendations to buy or sell any security. Top holdings exclude short-term holdings and cash, if applicable.

^†The Fund holds shares traded on both the Finnish and Swedish exchanges.

COLUMBIA ACORN EUROPEAN FUND^SM

AT A GLANCE

Total Net Assets of the Fund:
$56.4 million

The Growth of a $10,000 Investment in Columbia Acorn European Fund^SM Class Z Shares

August 19, 2011 (Fund inception) through June 30, 2015

This chart shows the change in value of a hypothetical $10,000 investment in Class Z shares of the Fund during the stated time period.

Average Annual Total Returns for period ended June 30, 2015

	2nd quarter			Year to date			1 year			Life of Fund
Class Z (8/19/11 inception)		2.30	%		6.80	%		-3.58	%		12.61	%
Class A (8/19/11 inception)
without sales charge		2.24			6.66			-3.84			12.32
with sales charge		-3.62			0.56			-9.35			10.61
S&P Europe Between $500M and $5B® Index*		5.03			10.62			-1.86			14.88

Results for other share classes can be found on Page 2.

*The Fund's primary benchmark. Please see Page 126 for index descriptions.

Returns for Class A shown with and without the maximum initial sales charge of 5.75%. As stated in the May 1, 2015, prospectus, the Fund's annual operating expense ratio is 1.50% for Class Z shares and 1.75% for Class A shares.

Portfolio Diversification

as a percentage of net assets, as of 6/30/15

Top 10 Holdings

as a percentage of net assets, as of 6/30/15

1.	Munksjo (Finland)† Specialty Paper Maker	3.6	%
2.	Assura (United Kingdom) UK Primary Health Care Property Developer	2.8	%
3.	Distribuidora Internacional de Alimentación (Spain) Discount Retailer in Spain & Latin America	2.7	%
4.	Partners Group (Switzerland) Private Markets Asset Management	2.4	%
5.	Charles Taylor (United Kingdom) Insurance Services	2.4	%
6.	Spirax Sarco (United Kingdom) Steam Systems for Manufacturing & Process Industries	2.3	%
7.	Neopost (France) Postage Meter Machines	2.1	%
8.	Aurelius (Germany) European Turnaround Investor	2.1	%
9.	Cable and Wireless (United Kingdom) Telecommunications Service Provider in the Caribbean	1.9	%
10.	William Demant Holding (Denmark) Manufacture & Distribution of Hearing Aids & Diagnostic Equipment	1.9	%

†The Fund holds shares traded on both the Finnish and Swedish exchanges.

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.

SQUIRREL CHATTER: BATTERY TECHNOLOGY AND ITS IMPLICATIONS

Battery History

Alessandro Volta was a professor of physics at the University of Pavia in Italy at a time of great debate about electricity. He was also a skilled maker of scientific instruments, including machines that could generate an electrostatic charge. After reading a paper noting a torpedo fish could create electric shocks, and proposing that the process creating the charge could be imitated, Volta created the undisputed first battery.¹ As described in a paper he wrote in March 1800, the battery consisted of a column of zinc and copper discs separated by brine-soaked cardboard.²

Within months, others were making variations of Volta's battery and improved versions were developed. The batteries were largely used in laboratory equipment, often to enable electrolysis, which resulted in scientific discoveries such as the separation of water into oxygen and hydrogen, as well as discoveries of other elements including sodium and magnesium.³ For several decades, electroplating of metal appears to have been the primary commercial use of batteries.⁴

All batteries have anode and cathode electrodes as well as an acid or alkaline electrolyte, which facilitates movement of electricity between the electrodes. Components in existing batteries have been refined over time and often later replaced by new materials. In 1839, Sir William Robert Grove, a Welsh judge and physical scientist, made a version utilizing zinc in sulfuric acid and platinum in nitric acid, which produced a then-powerful charge of 1.8 volts but emitted poisonous nitric oxide gas. In the 1850s, German chemist Robert Bunsen created a much cheaper version of Grove's battery by substituting carbon for platinum.⁵

Telegraphs were developed in the 1830s and 1840s, and became widespread after inventor Samuel Morse's 1844 Washington, D.C. to Baltimore link. That initial line used huge Grove batteries at both ends plus 150-pound Grove batteries at relay points in between. Within 30 years there were 650,000 land miles of telegraph cable⁶ and, since telegraphs then needed battery

powered relays every few miles to boost their signals, commercial demand for batteries boomed. Telegraph office batteries initially needed regular care on strict schedules. The electrodes had to be cleaned or replaced, and the electrolyte needed replenishing.⁷

The first practical rechargeable battery was developed in 1859⁸ by French physicist Gaston Planté using lead because it was readily available, cheap and amenable to recharging.⁹ The next battery breakthrough came in 1866 when French engineer Georges Leclanché created a simple, cheap battery consisting of a glass jar with manganese dioxide and zinc electrodes, a small bar of carbon, and an ammonium chloride electrolyte, which was then a common household chemical (sal ammoniac) used in cleaning and baking. This was the first battery not to use acid and, when discharged, replacing the sal ammoniac would revitalize it. Millions were produced for telegraphs, doorbells and telephones, though the battery was good only for intermittent use.¹⁰

German chemist Carl Gassner in 1887 patented his "dry cell" battery, consisting of a zinc can as the anode, ammonium chloride and plaster of paris as a dry electrolyte and carbon as the cathode. Producing a steady 1.5 volts, this was apparently the first battery requiring no maintenance. This compact six-inch long battery was durable and was mass-produced to power alarm clocks and bicycle lights.¹¹

Batteries powered many of the first cars. The 1894 Electrobat had 1,500 pounds of lead-acid batteries.¹² Of the 4,200 automobiles sold in the United States in the year 1900, battery powered cars were the most popular, followed by steam powered cars. Fewer than 1,000 were powered by gasoline.¹³

American inventor and businessman Thomas Edison was a proponent of battery-powered cars, and was determined to create a new rechargeable battery with triple the capacity of the lead-acid battery.¹⁴ His team experimented with hundreds of different compounds for a better automotive battery. When chided about failed experiments, he said, "No, I didn't fail. I discovered 24,999 ways that the storage battery does not work."¹⁵ Ultimately

he developed a battery with nickel and iron electrodes and a potassium-based electrolyte that outperformed existing lead-acid batteries by 233%.¹⁶ But it was expensive and gasoline-powered cars dominated once the automatic starter (as opposed to a crank) became ubiquitous.

In the 1950s, inventor Samuel Ruben created the alkaline manganese battery in a new AAA size, and licensed it to Mallory, which later became Duracell. That battery was popular in Kodak flash cameras. Canadian-American chemist Lewis Urry of Eveready invented the modern alkaline battery in 1959.¹⁷ His primary innovation was to use powdered zinc, which has dramatically more surface area than solid zinc. Labelled the Energizer, it had 40 times the capacity of the then-ubiquitous zinc-carbon battery.¹⁸

As power-hungry portable electronics took off after 1980, the quest for high energy, rechargeable batteries intensified. Nickel-cadmium batteries were invented, but had a "memory effect," which reduced capacity if recharged before depletion, and contained toxic cadmium. Nickel-metal-hydride batteries were also developed, powering cell phones and the first hybrid cars. These batteries had high capacity for the time, but tended to self-discharge when not in use.

Lithium Batteries

Chemists were long aware of lithium's potential in batteries. Lithium is the lightest metal, has half the density of water and, pound per pound, a lithium battery should be able to produce 30 times the energy of a lead-acid battery. However, lithium is too volatile to exist by itself in nature. It will burn or explode when exposed to air and pure lithium must be stored in oil to prevent it from reacting.

Exxon had a venture capital division that recruited British chemist Stanley Whittingham in the 1970s to pursue development of lithium batteries. Whittingham created a coin-sized battery with a lithium-aluminum alloy and a sulfide electrode. The first rechargeable lithium battery was used in a solar-powered watch shipped in 1977. But larger batteries ignited in Exxon's laboratories, and Exxon later exited the business and sold its patents.¹⁹

John Goodenough achieved the breakthrough in lithium batteries. A University of Chicago Ph.D. working at Oxford, he experimented with metal oxides, which could be charged and discharged at higher voltages than sulfides.

He also realized that as lithium ions migrate from a sulfide-based cathode, sections of the cathode tend to hollow out and collapse, reducing the ability of the battery to be recharged. Metal oxides in the cathode, in effect, reinforce its structure.

In 1980, Goodenough's team announced the lithium-cobalt-oxide battery.²⁰ His belief in oxides proved correct, as the battery produced about 4 volts versus the 2.4 volts Whittingham achieved.²¹ "It was the first lithium-ion cathode with the capacity to power both compact and relatively large devices...far superior to anything on the market," said author Steve Levine in his recently published book, The Powerhouse.²² Yet because the battery was unusual, no companies in Europe or the Americas licensed it.

South African Ph.D. Mike Thackeray joined Goodenough during a stint at Oxford and helped invent a nickel-manganese-cobalt (NMC) cathode in place of Goodenough's lithium-cobalt-oxide. The NMC version has less safety risk than Goodenough's first lithium battery and theoretically should provide more energy.²³ A version of this battery is used in the Chevrolet Volt.

Battery research funding diminished in the United States during the 1980s, a period of low oil prices and excitement about superconductivity. In Japan, however, battery research continued in earnest. After a decade of work, Japanese researcher Akira Yoshino combined Goodenough's lithium-cobalt-oxide cathode with a carbon anode and, in 1991, Sony shipped a resulting lithium-ion battery for small electronic devices. Later, Sony changed the anode to graphite, which was benign and better absorbed lithium ions, resulting in more power for longer periods. The Sony batteries were wildly successful, spurring knockoffs as well as additional lithium battery research.²⁴

Electric Cars and Other Uses for Batteries

Improving performance and dropping costs have enabled much more sophisticated portable electronics but the biggest potential market for batteries is in automobiles. Thomas Edison said that the internal combustion engine would be a bridge between generations of battery powered cars, and he yet could be proven right (albeit late).²⁵

The basic physics problem confronting battery powered vehicles is the energy density of gasoline versus batteries. A kilogram of gasoline contains about

12,700 watt hours of energy,²⁶ while lithium batteries currently used in automobiles have energy densities ranging from 155 to 233 watt hours per kilogram.²⁷ However, electric motors are over 90% efficient, three times that of gasoline engines,²⁸ and electric vehicles can recapture up to half of energy expended through regenerative breaking,²⁹ reducing the effective energy density gap somewhat.

Another key use for improved batteries is within the electric grid. Renewable power from solar and wind is by nature intermittent, and higher capacity, lower cost batteries will allow the adoption of more renewable energy. As battery performance improves and costs fall, expect to see more electric automobiles and renewable energy.

Potential Breakthroughs

In his book, Levine describes the inventions of various forms of lithium batteries and Argonne National Laboratory's successful effort to win funding as The Joint Center for Energy Storage Research. Argonne's goal is another battery breakthrough, achieving five times the performance at one-fifth the cost in five years. The Joint Center is looking beyond lithium. Argonne's senior scientist George Crabtree notes that new concepts, such as use of materials with double ions, use of reactions on the electrode surface instead of inside them and liquid electrodes, are worth exploring.

Investment Implications

Predicting which battery technology will succeed and which battery companies will profit is extremely difficult and risky. I've been on numerous battery technology wild goose chases, and can vaguely recall talking to Argonne researchers back in the late 1970s. The Columbia Acorn Funds' shareholders have instead benefitted from investing downstream, in companies that prospered from improved battery technology. For example, domestic funds had profitable investments in cell phone service providers as the industry consolidated years ago, and more recently in cell tower companies.

Charles P. McQuaid

Portfolio Manager, Analyst and Advisor
Columbia Wanger Asset Management, LLC

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

¹In 1936, archeologist Wilhelm Koenig found a five by three inch broken clay jar in Eastern Iraq that held a rolled sheet of copper and an iron rod. It dated back to between 200 BC and 200 AD. Koenig realized that with an acid or alkaline liquid, the device would be a functioning battery. Several similar jars have since been found. Google "Baghdad battery" to pursue the mystery and controversy.

²Seth Fletcher, Bottled Lightning: Superbatteries, Electric Cars, and the New Lithium Economy (New York, Hill and Wang, 2011), p. 11.

³Henry Schlesinger, The Battery: How Portable Power Sparked a Technological Revolution (New York, HarperCollins, 2010), p. 77.

⁴Ibid., p. 50, 65.

⁵Ibid., p. 96.

⁶Ibid., p. 110, 130.

⁷Ibid., p. 139.

⁸Fletcher, op. cit., p. 13.

⁹Schlesinger, op. cit., p. 145.

¹⁰Ibid., p. 142-143.

¹¹Ibid., p. 179.

¹²Ibid., p. 174.

¹³Jim Motavalli, High Voltage: The Fast Track To Plug In the Auto Industry (New York, Rodale, 2011), p. xii.

¹⁴ Fletcher, op. cit., p. 14.

¹⁵Schlesinger, op. cit., p. 174.

¹⁶Fletcher, op. cit., 15.

¹⁷NNDB website: nndb.com/people/004/000206383. Accessed April 2, 2015.

¹⁸Schlesinger, op. cit., p. 250.

¹⁹Steve Levine, The Powerhouse: Inside the Invention of a Battery to Save the World (New York, Viking, 2015), p. 21.

²⁰Ibid., p. 25.

²¹Fletcher, op. cit., p. 44.

²²Levine, op. cit., p. 25.

²³Ibid., p. 41-44.

²⁴Ibid., p. 35.

²⁵Schlesinger, op. cit., p. 174.

²⁶Hypertextbook website: hypertextbook.com/facts/2003/ArthurGolnik.shtml. Accessed April 1, 2015.

²⁷Luke Ottaway, "What Makes Tesla's Batteries So Great?" Torque News, October 19, 2014, on website at: torquenews.com/2250/what-makes-tesla-s-batteries-so-great. Accessed April 3, 2015.

²⁸Tobias Fleiter and Wolfgang Eichhammer, "Energy efficiency in electric motor systems: Technology, saving potentials and policy options for developing countries," Working Paper 11/2011, p. 5, published by United Nations Industrial Development Organization, unido.org. Accessed April 21, 2015.

²⁹Source: ProEv Inc. article titled, "Regenerative Braking Efficiency," 2015.

COLUMBIA ACORN FAMILY OF FUNDS

2015 MID-YEAR DISTRIBUTIONS

The following table lists the mid-year distributions for the Columbia Acorn Family of Funds. The record date was June 2, 2015,

and the ex-dividend and payable date was June 3, 2015. Columbia Acorn Emerging Markets Fund did not have any distributions.

Fund	Short-term Capital Gain		Long-term Capital Gain		Ordinary Income		Reinvestment Price
Columbia Acorn® Fund
Class A		None	$	1.64099		None	$	30.97
Class B		None	$	1.64099		None	$	26.82
Class C		None	$	1.64099		None	$	26.17
Class I		None	$	1.64099		None	$	32.88
Class R4		None	$	1.64099		None	$	33.39
Class R5		None	$	1.64099		None	$	33.43
Class Y		None	$	1.64099		None	$	33.51
Class Z		None	$	1.64099		None	$	32.79
Columbia Acorn International®
Class A		None	$	0.38368		None	$	44.63
Class B		None	$	0.38368		None	$	43.07
Class C		None	$	0.38368		None	$	42.89
Class I		None	$	0.38368		None	$	44.79
Class R		None	$	0.38368		None	$	44.55
Class R4		None	$	0.38368		None	$	45.03
Class R5		None	$	0.38368		None	$	44.72
Class Y		None	$	0.38368		None	$	45.07
Class Z		None	$	0.38368		None	$	44.73
Columbia Acorn USA®
Class A		None	$	0.84005		None	$	30.74
Class B		None	$	0.84005		None	$	26.41
Class C		None	$	0.84005		None	$	26.16
Class I		None	$	0.84005		None	$	33.03
Class R4		None	$	0.84005		None	$	33.57
Class R5		None	$	0.84005		None	$	33.60
Class Y		None	$	0.84005		None	$	33.69
Class Z		None	$	0.84005		None	$	32.84

COLUMBIA ACORN FAMILY OF FUNDS

2015 MID-YEAR DISTRIBUTIONS, CONTINUED

Fund	Short-term Capital Gain		Long-term Capital Gain		Ordinary Income		Reinvestment Price
Columbia Acorn International Select^SM
Class A		None		None	$	0.09778	$	23.31
Class B		None		None	$	0.01466	$	21.90
Class C		None		None	$	0.00000	$	21.75
Class I		None		None	$	0.09778	$	23.61
Class R4		None		None	$	0.09778	$	23.78
Class R5		None		None	$	0.09778	$	23.76
Class Y		None		None	$	0.09778	$	23.75
Class Z		None		None	$	0.09778	$	23.61
Columbia Acorn Select^SM
Class A		None	$	1.77870		None	$	20.70
Class B		None	$	1.77870		None	$	17.42
Class C		None	$	1.77870		None	$	17.07
Class I		None	$	1.77870		None	$	22.18
Class R4		None	$	1.77870		None	$	22.56
Class R5		None	$	1.77870		None	$	22.60
Class Y		None	$	1.77870		None	$	22.69
Class Z		None	$	1.77870		None	$	22.06
Columbia Thermostat Fund^SM
Class A	$	0.11593	$	0.16409	$	0.02233	$	14.80
Class B	$	0.11593	$	0.16409	$	0.02233	$	14.88
Class C	$	0.11593	$	0.16409	$	0.02233	$	14.86
Class R4	$	0.11593	$	0.16409	$	0.02233	$	14.69
Class R5	$	0.11593	$	0.16409	$	0.02233	$	14.71
Class Y	$	0.11593	$	0.16409	$	0.02233	$	14.69
Class Z	$	0.11593	$	0.16409	$	0.02233	$	14.62
Columbia Acorn European Fund^SM
Class A		None		None	$	0.06806	$	15.97
Class C		None		None	$	0.00000	$	15.79
Class I		None		None	$	0.06806	$	15.98
Class R4		None		None	$	0.06806	$	16.06
Class R5		None		None	$	0.06806	$	16.13
Class Z		None		None	$	0.06806	$	15.99

UNDERSTANDING YOUR EXPENSES

As a shareholder, you incur two types of costs. There are transaction costs, which generally include sales charges on purchases and may include redemption fees. There are also ongoing costs, which generally include management fees, distribution and service (Rule 12b-1) fees, and other Fund expenses. The following information is intended to help you understand your ongoing costs (in dollars) of investing in the Fund and to help you 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 Class A, B, C, I, R, R4, R5, Y and Z shares of the Funds during the period. The actual and hypothetical information in the tables is based on an initial investment of $1,000 at the beginning of the period indicated 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 the Funds' actual operating expenses and total return for the period. You may use the Actual information, together with the amount invested, to estimate the expenses that you paid over the period. Simply divide your account value by $1,000 (for example, an $8,600 account value divided by $1,000 = 8.6), then multiply the results by the expenses paid during the period under the Actual column. The amount listed in the "Hypothetical" column assumes a 5% annual rate of return before expenses (which is not the Funds' actual return) and then applies the Funds' actual expense ratio for the period to the hypothetical return. You should not use the hypothetical account values and expenses to estimate either your actual account balance at the end of the period or the expenses you paid during the period. See "Compare With Other Funds" below for details on how to use the hypothetical data.

In addition to the ongoing expenses which the Funds bear directly, Columbia Thermostat Fund's shareholders indirectly bear the Fund's allocable share of the costs and expenses of each underlying fund in which the Fund invests. You can also estimate the effective expenses paid during the period, which includes the indirect fees associated with investing in the underlying funds, by using the amounts listed in the effective expenses paid during the period column in the "Fund of Funds" table.

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 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 ongoing costs of investing in a fund only and do not reflect any transaction costs, such as sales charges, or redemption or exchange fees. Therefore, the hypothetical calculations are useful in comparing ongoing costs only, and will not help you determine the relative total costs of owning different funds. If transaction costs were included in these calculations, your costs would be higher.

January 1, 2015 – June 30, 2015

	Account value at the beginning of the period ($)				Account value at the end of the period ($)				Expenses paid during the period ($)				Fund's annualized expense ratio (%)
	Actual		Hypothetical		Actual		Hypothetical		Actual		Hypothetical		Actual
Columbia Acorn® Fund
Class A		1,000.00		1,000.00		1,064.50		1,019.39		5.58		5.46		1.09
Class B		1,000.00		1,000.00		1,060.40		1,015.42		9.66		9.44		1.89
Class C		1,000.00		1,000.00		1,060.70		1,015.92		9.15		8.95		1.79
Class I		1,000.00		1,000.00		1,066.30		1,021.22		3.69		3.61		0.72
Class R4		1,000.00		1,000.00		1,065.60		1,020.48		4.46		4.36		0.87
Class R5		1,000.00		1,000.00		1,065.80		1,020.98		3.94		3.86		0.77
Class Y		1,000.00		1,000.00		1,066.30		1,021.22		3.69		3.61		0.72
Class Z		1,000.00		1,000.00		1,066.10		1,020.83		4.10		4.01		0.80

UNDERSTANDING YOUR EXPENSES, continued

	Account value at the beginning of the period ($)				Account value at the end of the period ($)				Expenses paid during the period ($)				Fund's annualized expense ratio (%)
	Actual		Hypothetical		Actual		Hypothetical		Actual		Hypothetical		Actual
Columbia Acorn International®
Class A		1,000.00		1,000.00		1,050.50		1,018.65		6.30		6.21		1.24
Class B		1,000.00		1,000.00		1,046.10		1,014.48		10.55		10.39		2.08
Class C		1,000.00		1,000.00		1,046.30		1,014.98		10.05		9.89		1.98
Class I		1,000.00		1,000.00		1,052.30		1,020.48		4.43		4.36		0.87
Class R		1,000.00		1,000.00		1,048.60		1,016.86		8.13		8.00		1.60
Class R4		1,000.00		1,000.00		1,051.20		1,019.59		5.34		5.26		1.05
Class R5		1,000.00		1,000.00		1,051.90		1,020.28		4.63		4.56		0.91
Class Y		1,000.00		1,000.00		1,052.40		1,020.48		4.43		4.36		0.87
Class Z		1,000.00		1,000.00		1,051.80		1,020.08		4.83		4.76		0.95
Columbia Acorn USA®
Class A		1,000.00		1,000.00		1,071.40		1,018.15		6.88		6.71		1.34
Class B		1,000.00		1,000.00		1,064.50		1,012.30		12.90		12.57		2.52
Class C		1,000.00		1,000.00		1,067.60		1,014.83		10.30		10.04		2.01
Class I		1,000.00		1,000.00		1,073.40		1,020.18		4.78		4.66		0.93
Class R4		1,000.00		1,000.00		1,072.60		1,019.39		5.60		5.46		1.09
Class R5		1,000.00		1,000.00		1,073.20		1,019.84		5.14		5.01		1.00
Class Y		1,000.00		1,000.00		1,073.30		1,020.08		4.88		4.76		0.95
Class Z		1,000.00		1,000.00		1,072.50		1,019.39		5.60		5.46		1.09
Columbia Acorn International Select^SM
Class A		1,000.00		1,000.00		1,037.00		1,017.26		7.68		7.60		1.52
Class B		1,000.00		1,000.00		1,033.60		1,013.88		11.09		10.99		2.20
Class C		1,000.00		1,000.00		1,033.60		1,013.44		11.55		11.43		2.29
Class I		1,000.00		1,000.00		1,038.80		1,018.89		6.02		5.96		1.19
Class R4		1,000.00		1,000.00		1,038.60		1,018.60		6.32		6.26		1.25
Class R5		1,000.00		1,000.00		1,039.00		1,018.94		5.97		5.91		1.18
Class Y		1,000.00		1,000.00		1,039.10		1,019.24		5.66		5.61		1.12
Class Z		1,000.00		1,000.00		1,038.80		1,018.74		6.17		6.11		1.22
Columbia Acorn Select^SM
Class A		1,000.00		1,000.00		1,059.60		1,018.50		6.49		6.36		1.27
Class B		1,000.00		1,000.00		1,055.00		1,014.38		10.70		10.49		2.10
Class C		1,000.00		1,000.00		1,055.50		1,014.88		10.19		9.99		2.00
Class I		1,000.00		1,000.00		1,061.90		1,020.43		4.50		4.41		0.88
Class R4		1,000.00		1,000.00		1,060.80		1,019.64		5.31		5.21		1.04
Class R5		1,000.00		1,000.00		1,061.20		1,019.98		4.96		4.86		0.97
Class Y		1,000.00		1,000.00		1,061.40		1,020.33		4.60		4.51		0.90
Class Z		1,000.00		1,000.00		1,060.70		1,019.84		5.11		5.01		1.00

	Account value at the beginning of the period ($)				Account value at the end of the period ($)				Expenses paid during the period ($)				Fund's annualized expense ratio (%)
	Actual		Hypothetical		Actual		Hypothetical		Actual		Hypothetical		Actual
Columbia Acorn Emerging Markets Fund^SM
Class A		1,000.00		1,000.00		970.10		1,016.76		7.91		8.10		1.62
Class C		1,000.00		1,000.00		966.80		1,012.99		11.61		11.88		2.38
Class I		1,000.00		1,000.00		971.80		1,018.40		6.31		6.46		1.29
Class R4		1,000.00		1,000.00		971.20		1,018.20		6.50		6.66		1.33
Class R5		1,000.00		1,000.00		971.10		1,018.30		6.40		6.56		1.31
Class Y		1,000.00		1,000.00		971.70		1,018.70		6.01		6.16		1.23
Class Z		1,000.00		1,000.00		971.70		1,018.00		6.70		6.85		1.37
Columbia Acorn European Fund^SM
Class A		1,000.00		1,000.00		1,066.60		1,016.12		8.97		8.75		1.75
Class C		1,000.00		1,000.00		1,062.90		1,012.40		12.79		12.47		2.50
Class I		1,000.00		1,000.00		1,068.00		1,017.60		7.43		7.25		1.45
Class R4		1,000.00		1,000.00		1,067.70		1,017.36		7.69		7.50		1.50
Class R5		1,000.00		1,000.00		1,068.10		1,017.36		7.69		7.50		1.50
Class Z		1,000.00		1,000.00		1,068.00		1,017.36		7.69		7.50		1.50

Fund of Funds—Columbia Thermostat Fund

January 1, 2015 – June 30, 2015

	Account value at the beginning of the period ($)				Account value at the end of the period ($)				Expenses paid during the period ($)				Fund's annualized expense ratio (%)		Effective expenses paid during the period ($)				Fund's effective annualized expense ratio (%)
	Actual		Hypothetical		Actual		Hypothetical		Actual		Hypothetical		Actual		Actual		Hypothetical		Actual
Columbia Thermostat Fund^SM
Class A		1,000.00		1,000.00		1,010.80		1,022.32		2.49		2.51		0.50		5.04		5.06		1.01
Class B		1,000.00		1,000.00		1,008.10		1,019.84		4.98		5.01		1.00		7.52		7.56		1.51
Class C		1,000.00		1,000.00		1,007.40		1,018.60		6.22		6.26		1.25		8.76		8.81		1.76
Class R4		1,000.00		1,000.00		1,012.30		1,023.55		1.25		1.25		0.25		3.79		3.81		0.76
Class R5		1,000.00		1,000.00		1,012.30		1,023.65		1.15		1.15		0.23		3.69		3.71		0.74
Class Y		1,000.00		1,000.00		1,012.30		1,023.90		0.90		0.90		0.18		3.44		3.46		0.69
Class Z		1,000.00		1,000.00		1,012.30		1,023.60		1.20		1.20		0.24		3.74		3.76		0.75

Expenses paid during the period are equal to the 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.

Except with respect to Columbia Thermostat Fund, expenses do not include any fees and expenses incurred indirectly by a Fund from the underlying funds in which the Fund may invest (also referred to as "acquired funds"), including affiliated and non-affiliated pooled investments vehicles (including mutual funds and exchange traded funds).

In the case of Columbia Thermostat Fund, effective expenses paid during the period and the Fund's effective annualized expense ratio include expenses borne directly by the class plus the Fund's pro rata portion of the ongoing expenses charged by the underlying funds in which it invests using the expense ratio of each class of each underlying fund as of the underlying fund's most recent shareholder report.

Had the investment manager and/or certain of its affiliates not waived/reimbursed certain fees and expenses for Columbia Acorn International, Columbia Acorn International Select, Columbia Acorn Select, Columbia Thermostat Fund and Columbia Acorn European Fund, account value at the end of the period would have been reduced. See Note 4 to the Financial Statements (Unaudited).

COLUMBIA ACORN® FUND

MAJOR PORTFOLIO CHANGES IN THE SECOND QUARTER (UNAUDITED)

	Number of Shares
	3/31/15		6/30/15
Purchases
Information
Bankrate		7,250,000		7,350,000
Cadence Design Systems		4,155,000		4,514,783
Sanmina		3,100,000		3,467,599
Health Care
Abaxis		595,000		631,624
Agios Pharmaceuticals		275,000		346,692
Align Technology		513,000		777,276
Henry Schein		291,100		349,334
VWR		1,375,400		1,850,600
Wright Medical Group		1,729,500		1,829,940
Consumer Goods & Services
Gentex		2,732,952		4,350,000
Hertz		2,531,000		2,800,000
HomeAway		2,142,000		2,160,506
The Fresh Market		1,492,000		2,561,000
Zulily		425,245		2,405,817
Other Industries
Heartland Express		1,800,000		2,296,684
Energy & Minerals
PDC Energy		501,000		681,333

	Number of Shares
	3/31/15		6/30/15
Sales
Information
Amphenol		4,010,000		3,468,610
Ansys		1,806,000		1,530,948
Atmel		4,467,000		3,736,317
Audience		1,644,000		0
Avnet		1,621,000		1,151,958
Belden		450,000		427,810
Boingo Wireless		2,900,000		2,727,319
CalAmp		1,619,000		1,269,759
Cogent Communications		1,572,000		769,047
Crown Castle International		800,000		747,504
DemandWare		561,300		0
Discovery Communications Series C		1,154,000		402,028
Envestnet		610,000		0
F5 Networks		629,000		491,008
Fleetmatics		699,000		0
FLIR Systems		1,895,000		1,596,221
Genpact		1,531,000		1,419,083
Global Eagle Entertainment		2,001,000		1,808,895
Global Payments		1,261,000		941,314
Gogo		3,458,800		2,208,178
GTT Communications		2,601,000		2,502,088
Hackett Group		2,700,000		2,643,045
IGATE		3,650,000		0
IMAX (Canada)		1,250,000		860,159
inContact		3,741,000		2,244,897
Infinera		2,568,000		1,940,827
Informatica		2,080,000		0
IPG Photonics		1,399,000		1,143,460
Lamar Advertising		725,000		550,749
Liberty Global Series A		800,000		661,980
Liberty Global Series C		366,000		235,822
Littelfuse		367,000		319,938
Mettler-Toledo International		911,000		532,255
Monolithic Power Systems		427,000		378,172
Navigant Consulting		3,100,000		3,041,462
Rogers		539,000		494,334
RPX		2,570,000		1,908,954
Rubicon Technology		2,500,000		2,371,155
SBA Communications		1,300,000		839,317
Solera Holdings		1,668,000		1,650,392
SPS Commerce		1,076,000		940,526
Stratasys		504,000		0
Towerstream		4,000,000		3,775,680
Trimble Navigation		3,458,000		2,575,640
Tyler Technologies		220,000		0
Ultimate Software		554,000		543,708
VeriFone Holdings		1,250,000		1,003,359
Verint Systems		1,306,000		1,258,046
Verisign		1,210,000		887,506

See accompanying notes to financial statements.

	Number of Shares
	3/31/15		6/30/15
Sales (continued)
Information—continued
Verisk Analytics		1,429,000		1,170,274
Virtusa		1,570,000		1,263,525
Vonage		14,500,000		14,475,223
Zayo Group Holdings		1,150,000		867,000
Zebra Technologies		474,000		432,513
Zee Entertainment Enterprises		5,500,000		0
Industrial Goods & Services
Acuity Brands		726,000		0
Airgas		853,000		823,571
Allegion		626,000		609,008
Ametek		6,910,000		4,569,066
Drew Industries		1,610,000		1,434,286
Expeditors International of Washington		1,800,000		1,674,435
Fortune Brands Home & Security		660,000		0
Forward Air		1,500,000		1,359,907
Generac		2,982,000		2,563,598
HEICO		3,514,750		2,962,178
Kennametal		2,592,000		1,344,966
LKQ		7,481,000		6,748,927
Middleby		968,200		803,972
Moog		2,027,000		1,440,787
Nordson		3,034,000		2,147,586
NVR		96,000		76,850
Oshkosh Corporation		2,100,000		1,942,945
Pall		846,000		0
Quanta Services		3,400,000		3,357,357
Thermon		1,983,829		1,639,635
Toro		1,486,000		1,353,698
WABCO Holdings		946,000		595,235
Wabtec		1,021,000		625,474
WESCO International		1,553,000		851,347
Finance
Allied World Assurance Company Holdings		2,000,000		864,371
Associated Banc-Corp		9,414,000		7,931,448
BOK Financial		2,027,000		1,799,411
CNO Financial Group		7,300,000		5,651,291
Eaton Vance		3,463,508		2,914,581
First Busey		4,296,286		4,112,881
Hancock Holding		1,730,000		1,350,879
HCC Insurance Holdings		910,000		0
Leucadia National		3,875,000		3,760,346
MB Financial		2,420,000		1,790,025
McGrath Rentcorp		1,345,000		1,167,476
MSCI		195,201		0
RLI		800,000		606,457
Sandy Spring Bancorp		1,163,480		1,014,983
SEI Investments		7,368,774		6,522,307

	Number of Shares
	3/31/15		6/30/15
SVB Financial Group		840,000		677,700
TrustCo Bank		3,136,500		3,089,176
WEX		863,000		703,142
World Acceptance		787,422		530,000
Heath Care
Akorn		3,048,000		2,503,151
Allscripts Healthcare Solutions		2,746,200		1,749,965
Alnylam Pharmaceuticals		302,300		0
Bio-Techne		1,169,200		1,123,116
Castlight Health		487,818		0
Celldex Therapeutics		2,140,400		1,902,687
Cepheid		4,909,800		4,065,050
Envision Healthcare Holdings		1,239,000		1,155,575
Intercept Pharmaceuticals		269,200		220,978
Medidata Solutions		1,549,500		1,430,434
Sarepta Therapeutics		2,523,900		2,404,789
Seattle Genetics		2,548,000		1,823,556
Sirona Dental Systems		460,900		435,820
Synageva BioPharma		1,950,318		0
Consumer Goods & Services
Avis Budget Group		2,450,000		1,806,776
Burlington Stores		786,900		0
Casey's General Stores		791,839		596,335
Cavco Industries		500,000		455,025
DSW		533,500		0
Knoll		2,836,000		2,520,350
Michaels Stores		642,492		0
Papa John's International		950,000		937,570
Pool		1,444,000		1,274,436
Popeyes Louisiana Kitchen		650,000		454,079
PVH		456,000		0
Select Comfort		2,224,284		2,158,630
Shutterfly		771,056		0
United Natural Foods		1,286,000		1,192,643
Urban Outfitters		508,000		492,129
Vail Resorts		895,600		817,499
Williams-Sonoma		595,200		567,295
Other Industries
EdR		2,450,000		2,325,332
Eversource Energy		1,600,000		1,036,839
Extra Space Storage		1,467,000		1,002,619
Federal Realty		717,000		658,669
JB Hunt Transport Services		669,000		578,406
Jones Lang LaSalle		325,000		282,596
Kirby		720,000		0
Rush Enterprises, Class A		2,650,000		2,173,034
Rush Enterprises, Class B		550,000		460,172
Wisconsin Energy		577,000		0

See accompanying notes to financial statements.

COLUMBIA ACORN® FUND

MAJOR PORTFOLIO CHANGES IN THE SECOND QUARTER (UNAUDITED), CONTINUED

	Number of Shares
	3/31/15		6/30/15
Sales (continued)
Energy & Minerals
Alamos Gold (Canada)		3,500,000		3,421,322
Argonaut Gold (Canada)		9,014,700		8,582,916
Carrizo Oil & Gas		1,037,000		944,733
Cimarex Energy		420,000		402,497
Clayton Williams		281,000		265,636
Core Labs (Netherlands)		423,000		407,938
Energen Corporation		732,000		501,139
Hornbeck Offshore		1,470,000		1,147,145
Kirkland Lake Gold (Canada)		6,697,200		6,115,764
Petromanas (Canada)		67,500,000		64,294,000
Rosetta Resources		1,550,000		0
ShawCor (Canada)		1,797,579		1,740,523
SM Energy		778,000		685,658

See accompanying notes to financial statements.

COLUMBIA ACORN® FUND

STATEMENT OF INVESTMENTS (UNAUDITED), JUNE 30, 2015

Number of Shares			Value
			Equities: 93.6%
Information 26.1%
		> Business Software 5.4%
	1,530,948	Ansys (a)	$	139,683,695
		Simulation Software for Engineers & Designers
	543,708	Ultimate Software (a)		89,352,973
		Human Capital Management Systems
	4,514,783	Cadence Design Systems (a)		88,760,634
		Electronic Design Automation Software
	1,258,046	Verint Systems (a)		76,420,004
		Contact Center & Security Software
	1,650,392	Solera Holdings		73,541,468
		Software for Automotive Insurance Claims Processing
	940,526	SPS Commerce (a)(b)		61,886,611
		Supply Chain Management Software Delivered via the Web
	570,149	NetSuite (a)		52,311,171
		End-to-end IT Solution Delivered via the Web
	1,134,283	Textura (a)(c)		31,567,096
		Construction Vendor Management Software
	2,244,897	inContact (a)		22,157,133
		Call Center Systems Delivered via the Web & Telco Services
	205,225	Cvent (a)		5,290,700
		Software for Corporate Event Planners & Marketing Platform for Hotels
				640,971,485
		> Instrumentation 3.3%
	532,255	Mettler-Toledo International (a)		181,743,792
		Laboratory Equipment
	1,143,460	IPG Photonics (a)		97,394,206
		Fiber Lasers
	2,575,640	Trimble Navigation (a)		60,424,514
		GPS-based Instruments
	1,596,221	FLIR Systems		49,195,531
		Infrared Cameras
				388,758,043
		> Computer Hardware & Related Equipment 3.0%
	3,468,610	Amphenol		201,075,322
		Electronic Connectors
	432,513	Zebra Technologies (a)		48,030,569
		Bar Code Printers & Mobile Computers
	427,810	Belden		34,751,006
		Specialty Cable
	1,003,359	VeriFone Holdings (a)		34,074,071
		Point of Sale Systems
	494,334	Rogers (a)		32,695,251
		Printed Circuit Materials & High Performance Foams
				350,626,219
		> Mobile Communications 2.5%
	839,317	SBA Communications (a)		96,496,275
		Communications Towers
	34,500,000	Globalstar (a)		72,795,000
		Satellite Mobile Voice & Data Carrier

Number of Shares			Value
	747,504	Crown Castle International	$	60,024,571
		Communications Towers
	2,208,178	Gogo (a)(c)		47,321,255
		Provider of Wi-Fi on Airplanes
	1,808,895	Global Eagle Entertainment (a)(c)		23,551,813
		Provider of Entertainment & Wi-Fi on Airplanes
				300,188,914
		> Business Information & Marketing Services 2.3%
	1,170,274	Verisk Analytics (a)		85,149,136
		Risk & Decision Analytics
	7,350,000	Bankrate (a)(b)		77,101,500
		Internet Advertising for the Insurance, Credit Card & Banking Markets
	3,041,462	Navigant Consulting (a)(b)		45,226,540
		Financial Consulting Firm
	1,908,954	RPX (a)		32,261,323
		Patent Aggregation & Defensive Patent Consulting
	223,000	Dun & Bradstreet		27,206,000
		Commercial Data Provider
				266,944,499
		> Computer Services 1.9%
	1,263,525	Virtusa (a)		64,945,185
		Offshore IT Outsourcing
	2,021,597	WNS - ADR (a)		54,077,720
		Offshore Business Process Outsourcing Services
	1,333,000	ExlService Holdings (a)		46,095,140
		Business Process Outsourcing
	2,643,045	Hackett Group (b)		35,496,094
		IT Integration & Best Practice Research
	1,419,083	Genpact (a)		30,269,040
		Business Process Outsourcing
				230,883,179
		> Internet Related 1.3%
	14,475,223	Vonage (a)(b)		71,073,345
		Business & Consumer Internet Telephony
	887,506	Verisign (a)(c)		54,776,870
		Internet Domain Registry for .com/.net (Approximately 50% of World Domains)
	1,830,000	RetailMeNot (a)		32,628,900
		Digital Coupon Marketplace
				158,479,115
		> Financial Processors 1.3%
	941,314	Global Payments		97,378,933
		Credit Card Processor
	1,005,000	CoreLogic (a)		39,888,450
		Data Processing Services for Real Estate, Insurance, & Mortgages
	1,600,000	Liquidity Services (a)(b)		15,408,000
		E-Auctions for Surplus & Salvage Goods
				152,675,383
		> Telephone & Data Services 1.2%
	2,502,088	GTT Communications (a)(b)		59,724,841
		Provider of High Capacity Data Transit
	769,047	Cogent Communications		26,024,550
		Internet Data Pipelines

See accompanying notes to financial statements.

COLUMBIA ACORN® FUND

STATEMENT OF INVESTMENTS (UNAUDITED), CONTINUED

Number of Shares			Value
		> Telephone & Data Services—continued
	2,727,319	Boingo Wireless (a)(b)	$	22,527,655
		Wi-Fi & Cellular Communications Networks
	867,000	Zayo Group Holdings (a)(c)		22,299,240
		Fiber Optic Data Communications
	3,775,680	Towerstream (a)(b)		6,758,467
		High Speed Wireless, Rooftop Antenna Space & Wi-Fi Offload
				137,334,753
		> Telecommunications Equipment 1.0%
	491,008	F5 Networks (a)		59,092,813
		Internet Traffic Management Equipment
	1,940,827	Infinera (a)		40,718,551
		Optical Networking Equipment
	1,269,759	CalAmp (a)		23,185,799
		Machine-to-machine Communications
				122,997,163
		> Semiconductors & Related Equipment 0.8%
	3,736,317	Atmel		36,821,404
		Microcontrollers, Radio Frequency & Memory Semiconductors
	319,938	Littelfuse		30,358,917
		Little Fuses
	378,172	Monolithic Power Systems		19,177,102
		High Performance Analog & Mixed Signal Integrated Circuits
	2,371,155	Rubicon Technology (a)(b)(c)		5,761,907
		Producer of Sapphire for the Lighting, Electronics & Automotive Industries
				92,119,330
		> Contract Manufacturing 0.6%
	3,467,599	Sanmina (a)		69,906,796
		Electronic Manufacturing Services
		> Cable TV 0.5%
	661,980	Liberty Global Series A (a)		35,793,259
	235,822	Liberty Global Series C (a)		11,939,668
		Cable TV Franchises Outside of the United States
	402,028	Discovery Communications Series C (a)		12,495,030
		Cable TV Programming
				60,227,957
		> Electronics Distribution 0.4%
	1,151,958	Avnet		47,356,993
		Electronic Components Distribution
		> Entertainment Programming 0.3%
	860,159	IMAX (Canada) (a)		34,638,603
		IMAX Movies, Theater Equipment & Theater Joint Ventures
		> Advertising 0.3%
	550,749	Lamar Advertising		31,657,053
		Outdoor Advertising
Information: Total				3,085,765,485

Number of Shares			Value
Industrial Goods & Services 21.9%
		> Machinery 13.5%
	7,949,116	Donaldson (b)	$	284,578,353
		Industrial Air Filtration
	4,569,066	Ametek		250,293,435
		Aerospace/Industrial Instruments
	2,147,586	Nordson		167,275,474
		Dispensing Systems for Adhesives & Coatings
	2,962,178	HEICO (b)		150,389,777
		FAA-approved Aircraft Replacement Parts
	2,563,598	Generac (a)(c)		101,903,021
		Standby Power Generators
	1,440,787	Moog (a)		101,834,825
		Motion Control Products for Aerospace, Defense & Industrial Markets
	1,353,698	Toro		91,753,650
		Turf Maintenance Equipment
	803,972	Middleby (a)		90,229,778
		Manufacturer of Cooking Equipment
	1,942,945	Oshkosh Corporation		82,342,009
		Specialty Truck Manufacturer
	595,235	WABCO Holdings (a)		73,642,474
		Truck & Bus Component Supplier
	625,474	Wabtec		58,944,670
		Freight & Transit Component Supplier
	1,489,000	ESCO Technologies (b)		55,703,490
		Industrial Filtration & Advanced Measurement Equipment
	1,344,966	Kennametal		45,890,240
		Consumable Cutting Tools
	954,332	Dorman Products (a)(c)		45,483,463
		Aftermarket Auto Parts Distributor
				1,600,264,659
		> Other Industrial Services 3.8%
	6,748,927	LKQ (a)		204,121,297
		Alternative Auto Parts Distribution
	1,798,000	Robert Half International		99,789,000
		Temporary & Permanent Staffing in Finance, Accounting & other Professions
	1,674,435	Expeditors International of Washington		77,199,826
		International Freight Forwarder
	1,359,907	Forward Air		71,068,740
		Freight Transportation Between Airports
				452,178,863
		> Construction 1.5%
	76,850	NVR (a)		102,979,000
		Homebuilder
	2,865,200	PGT (a)(b)		41,574,052
		Wind Resistant Windows & Doors
	609,008	Allegion		36,625,741
		Mechanical & Electronic Security Systems
				181,178,793
		> Industrial Distribution 1.2%
	823,571	Airgas		87,117,340
		Industrial Gas Distributor
	851,347	WESCO International (a)		58,436,458
		Industrial Distributor
				145,553,798

See accompanying notes to financial statements.

Number of Shares			Value
		> Outsourcing Services 0.8%
	3,357,357	Quanta Services (a)	$	96,759,029
		Electrical Transmission & Pipeline Contracting Services
		> Industrial Materials & Specialty Chemicals 0.7%
	1,434,286	Drew Industries (b)		83,217,274
		RV & Manufactured Home Components
		> Electrical Components 0.4%
	1,639,635	Thermon (a)(b)		39,466,014
		Global Engineered Thermal Solutions
Industrial Goods & Services: Total				2,598,618,430
Finance 12.2%
		> Banks 4.8%
	7,931,448	Associated Banc-Corp (b)		160,770,451
		Midwest Bank
	1,799,411	BOK Financial		125,203,018
		Tulsa-based Southwest Bank
	677,700	SVB Financial Group (a)		97,575,246
		Bank to Venture Capitalists
	1,790,025	MB Financial		61,648,461
		Chicago Bank
	1,350,879	Hancock Holding		43,106,549
		Gulf Coast Bank
	1,014,983	Sandy Spring Bancorp		28,399,224
		Baltimore & Washington, D.C. Bank
	4,112,881	First Busey		27,021,628
		Illinois Bank
	3,089,176	TrustCo Bank		21,716,907
		New York State Bank
				565,441,484
		> Brokerage & Money Management 3.8%
	6,522,307	SEI Investments		319,788,712
		Mutual Fund Administration & Investment Management
	2,914,581	Eaton Vance		114,047,554
		Specialty Mutual Funds
	11,000,000	Sprott (Canada) (c)		21,753,403
		Asset Manager Focused on Resources, Particularly Gold & Silver
				455,589,669
		> Insurance 1.4%
	5,651,291	CNO Financial Group		103,701,190
		Life, Long-term Care & Medical Supplement Insurance
	864,371	Allied World Assurance Company Holdings		37,358,115
		Commercial Lines Insurance/Reinsurance
	606,457	RLI		31,165,825
		Specialty Insurance
				172,225,130
		> Diversified Financial Companies 0.8%
	3,760,346	Leucadia National		91,301,201
		Holding Company
		> Finance Companies 0.7%
	1,167,476	McGrath Rentcorp		35,526,295
		Mini-rental Conglomerate

Number of Shares			Value
	530,000	World Acceptance (a)(b)(c)	$	32,600,300
		Personal Loans
	839,000	CAI International (a)		17,275,010
		International Container Leasing
				85,401,605
		> Credit Cards 0.7%
	703,142	WEX (a)		80,137,094
		Card Processor
Finance: Total				1,450,096,183
Health Care 12.2%
		> Biotechnology & Drug Delivery 4.0%
	1,712,134	Ultragenyx Pharmaceutical (a)		175,305,400
		Biotech Focused on "Ultra-Orphan" Drugs
	1,823,556	Seattle Genetics (a)		88,260,111
		Antibody-based Therapies for Cancer
	2,404,789	Sarepta Therapeutics (a)(b)(c)		73,177,729
		Biotech Focused on Rare Diseases
	220,978	Intercept Pharmaceuticals (a)		53,339,670
		Biotech Developing Drugs for Several Diseases
	1,902,687	Celldex Therapeutics (a)		47,985,766
		Biotech Developing Drugs for Cancer
	346,692	Agios Pharmaceuticals (a)(c)		38,531,349
		Biotech Focused on Cancer & Orphan Diseases
	359,944	MicroDose Therapeutx Contingent Value Rights (a)(d)(e)		359,944
		Drug Inhaler Development
				476,959,969
		> Medical Supplies 3.9%
	4,065,050	Cepheid (a)(b)		248,577,807
		Molecular Diagnostics
	1,123,116	Bio-Techne		110,593,233
		Maker of Consumables & Systems for the Life Science Market
	349,334	Henry Schein (a)		49,647,348
		Distributor of Dental, Vet & Medical Products
	1,850,600	VWR (a)		49,466,538
		Distributor of Lab Supplies
				458,284,926
		> Health Care Services 1.9%
	1,430,434	Medidata Solutions (a)		77,701,175
		Cloud-based Software for Drug Studies
	1,647,700	HealthSouth		75,893,062
		Inpatient Rehabilitation Facilities & Home Health Care
	1,155,575	Envision Healthcare Holdings (a)		45,622,101
		Provider of Health Care Outsourcing Services
	1,749,965	Allscripts Healthcare Solutions (a)		23,939,521
		Health Care IT
				223,155,859
		> Medical Equipment & Devices 1.5%
	777,276	Align Technology (a)		48,742,978
		Invisalign System to Correct Malocclusion (Crooked Teeth)
	1,829,940	Wright Medical Group (a)		48,054,224
		Foot & Ankle Replacement
	435,820	Sirona Dental Systems (a)		43,765,044
		Manufacturer of Dental Equipment

See accompanying notes to financial statements.

COLUMBIA ACORN® FUND

STATEMENT OF INVESTMENTS (UNAUDITED), CONTINUED

Number of Shares			Value
		> Medical Equipment & Devices—continued
	631,624	Abaxis	$	32,516,004
		Instruments & Tests for Vet & Medical Markets
				173,078,250
		> Pharmaceuticals 0.9%
	2,503,151	Akorn (a)		109,287,573
		Developer, Manufacturer & Distributor of Specialty Generic Drugs
Health Care: Total				1,440,766,577
Consumer Goods & Services 11.6%
		> Travel 2.8%
	817,499	Vail Resorts		89,270,891
		Ski Resort Operator & Developer
	1,806,776	Avis Budget Group (a)		79,642,686
		Car Rental Company
	2,160,506	HomeAway (a)		67,234,946
		Vacation Rental Online Marketplace
	2,800,000	Hertz (a)		50,736,000
		U.S. Rental Car Operator
	720,955	Choice Hotels		39,111,809
		Franchisor of Budget Hotel Brands
				325,996,332
		> Retail 2.6%
	2,561,000	The Fresh Market (a)(b)		82,310,540
		Specialty Food Retailer
	874,735	Fossil (a)		60,671,619
		Watch Designer & Retailer
	596,335	Casey's General Stores		57,093,113
		Owner/Operator of Convenience Stores
	567,295	Williams-Sonoma		46,671,360
		Home Goods & Furnishing Retailer
	2,405,817	Zulily (a)(c)		31,371,854
		E-Commerce Retailer Offering Flash Sale Events
	492,129	Urban Outfitters (a)		17,224,515
		Multi-channel Apparel & Accessory Retailer
	2,100,000	Gaiam (a)(b)		13,734,000
		Promoter of Healthy Living through Catalogs, E-Commerce & Gaiam TV
				309,077,001
		> Restaurants 1.8%
	937,570	Papa John's International		70,889,668
		Franchisor of Pizza Restaurants
	403,000	Domino's Pizza		45,700,200
		Franchisor of Pizza Restaurants
	856,484	Fiesta Restaurant Group (a)		42,824,200
		Owner/Operator of Two Restaurant Chains: Pollo Tropical & Taco Cabana
	576,000	Dunkin Brands		31,680,000
		Franchisor of Quick Service Restaurants
	454,079	Popeyes Louisiana Kitchen (a)		27,240,199
		Popeyes Restaurants
				218,334,267
		> Other Durable Goods 1.6%
	4,350,000	Gentex		71,427,000
		Manufacturer of Auto Parts
	2,158,630	Select Comfort (a)		64,910,004
		Specialty Mattresses
	455,025	Cavco Industries (a)(b)		34,327,086
		Manufactured Homes

Number of Shares			Value
	411,825	Tenneco (a)	$	23,655,228
		Auto Parts for Emission Control, Suspension
				194,319,318
		> Consumer Goods Distribution 1.6%
	1,274,436	Pool		89,439,919
		Swimming Pool Supplies & Equipment Distributor
	1,192,643	United Natural Foods (a)		75,947,506
		Distributor of Natural/Organic Foods to Grocery Stores
	863,000	The Chefs' Warehouse (a)(c)		18,330,120
		Distributor of Specialty Foods to Fine Dining Restaurants
				183,717,545
		> Furniture & Textiles 0.9%
	2,520,350	Knoll (b)		63,084,360
		Office Furniture
	540,000	Caesarstone (Israel)		37,011,600
		Quartz Countertops
				100,095,960
		> Other Consumer Services 0.3%
	978,253	Blackhawk Network (a)		40,304,024
		Third-party Distributor of Prepaid Content, Mostly Gift Cards
Consumer Goods & Services: Total				1,371,844,447
Other Industries 5.8%
		> Real Estate 3.8%
	658,669	Federal Realty		84,368,912
		Shopping Centers & Mixed Use Projects
	2,325,332	EdR		72,922,411
		Student Housing
	1,316,297	Post Properties		71,567,068
		Multifamily Properties
	1,002,619	Extra Space Storage		65,390,811
		Self Storage Facilities
	183,970	Amerco		60,141,633
		North American Moving & Storage King
	282,596	Jones Lang LaSalle		48,323,916
		Real Estate Services
	2,148,681	Terreno Realty (b)		42,329,016
		Industrial Properties
				445,043,767
		> Transportation 1.6%
	2,173,034	Rush Enterprises, Class A (a)(b)		56,955,221
	460,172	Rush Enterprises, Class B (a)(b)		11,044,128
		Truck Sales & Service
	578,406	JB Hunt Transport Services		47,481,349
		Truck & Intermodal Carrier
	2,296,684	Heartland Express		46,461,917
		Regional Trucker
	380,000	Genesee & Wyoming (a)		28,948,400
		Short-line Operator
				190,891,015

See accompanying notes to financial statements.

Number of Shares			Value
		> Regulated Utilities 0.4%
	1,036,839	Eversource Energy	$	47,082,859
		Regulated Electric Utility
Other Industries: Total				683,017,641
Energy & Minerals 3.8%
		> Oil & Gas Producers 1.9%
	944,733	Carrizo Oil & Gas (a)		46,518,653
		Oil & Gas Producer
	402,497	Cimarex Energy		44,399,444
		Oil & Gas Producer in Texas, New Mexico & Oklahoma
	681,333	PDC Energy (a)		36,546,702
		Oil & Gas Producer in the United States
	501,139	Energen Corporation		34,227,793
		Oil & Gas Producer with Natural Gas Utility
	685,658	SM Energy		31,622,547
		Oil & Gas Producer
	265,636	Clayton Williams (a)		17,465,567
		Oil & Gas Producer
	107,561,001	ShaMaran Petroleum (Iraq) (a)(b)		7,965,887
		Oil Exploration & Production in Kurdistan
	64,294,000	Petromanas (Canada) (a)(b)(c)		2,831,201
		Exploring for Oil in Albania
	24,115,500	Canadian Overseas Petroleum (Canada) (a)(b)		1,544,628
	8,400,000	Canadian Overseas Petroleum (Canada) (a)(b)(e)		511,129
		Oil & Gas Exploration Offshore West Africa
				223,633,551
		> Mining 0.9%
	407,938	Core Labs (Netherlands) (c)		46,521,249
		Oil & Gas Reservoir Consulting
	6,115,764	Kirkland Lake Gold (Canada) (a)(b)		27,567,455
		Gold Mining
	3,421,322	Alamos Gold (Canada)		19,366,490
		Gold Mining
	8,582,916	Argonaut Gold (Canada) (a)(b)(c)		11,544,675
		Gold & Silver Mining
	3,412,300	Silvercrest Mines (a)		3,387,712
		Gold & Silver Mining
	3,000,000	Kaminak Gold (a)		1,897,518
		Exploration Stage Canadian Gold Miner
				110,285,099
		> Oil Services 0.9%
	1,740,523	ShawCor (Canada)		50,989,381
		Oil & Gas Pipeline Products

Number of Shares			Value
	774,708	Gulfport Energy (a)	$	31,181,997
		Oil & Gas Producer Focused on Utica Shale in Ohio
	1,147,145	Hornbeck Offshore (a)		23,550,887
		Supply Vessel Operator in Gulf of Mexico
				105,722,265
		> Agricultural Commodities 0.1%
	1,306,818	Union Agriculture Group (Uruguay) (a)(d)(e)		12,336,362
		Farmland Operator in Uruguay
Energy & Minerals: Total				451,977,277
Total Equities: 93.6% (Cost: $6,035,022,717)				11,082,086,040	(f)
Short-Term Investments 6.8%
	520,578,010	JPMorgan U.S. Government Money Market Fund, Agency Shares (7 day yield of 0.01%)		520,578,010
	280,000,000	JPMorgan U.S. Government Money Market Fund, IM Shares (7 day yield of 0.01%)		280,000,000
Total Short-Term Investments: 6.8% (Cost: $800,578,010)				800,578,010
Securities Lending Collateral 1.7%
	205,638,386	Dreyfus Government Cash Management Fund, Institutional Shares (7 day yield of 0.01%) (g)		205,638,386
Total Securities Lending Collateral: 1.7% (Cost: $205,638,386)				205,638,386
Total Investments: 102.1% (Cost: $7,041,239,113)(h)				12,088,302,436
Obligation to Return Collateral for Securities Loaned: (1.7)%				(205,638,386	)
Cash and Other Assets Less Liabilities: (0.4)%				(45,065,488	)
Net Assets: 100.0%			$	11,837,598,562

ADR - American Depositary Receipts

See accompanying notes to financial statements.

COLUMBIA ACORN® FUND

STATEMENT OF INVESTMENTS (UNAUDITED), CONTINUED

> Notes to Statement of Investments

(a) Non-income producing security.

(b) An affiliated person of the Fund, as defined in the Investment Company Act of 1940, may include any company in which the Fund owns five percent or more of its outstanding voting shares. Holdings and transactions in these affiliated companies during the period ended June 30, 2015, are as follows:

Security	Balance of Shares Held 12/31/14		Purchases/ Additions		Sales/ Reductions		Balance of Shares Held 6/30/15		Value		Dividend
Donaldson		7,952,000		-		2,884		7,949,116	$	284,578,353	$	2,663,430
Cepheid		5,350,800		-		1,285,750		4,065,050		248,577,807		-
Nordson (1)		3,130,000		-		982,414		2,147,586		167,275,474		1,197,148
Associated Banc-Corp		9,000,000		414,000		1,482,552		7,931,448		160,770,451		1,789,603
HEICO		3,626,750		-		664,572		2,962,178		150,389,777		-
Generac (1)		3,632,000		-		1,068,402		2,563,598		101,903,021		-
Moog (1)		2,456,000		-		1,015,213		1,440,787		101,834,825		-
Drew Industries		1,610,000		-		175,714		1,434,286		83,217,274		3,220,000
The Fresh Market	1,492,000				1,069,000		-		2,561,000		82,310,540
Bankrate		6,300,300		1,049,700		-		7,350,000		77,101,500		-
Sarepta Therapeutics		2,523,900		-		119,111		2,404,789		73,177,729		-
EdR (1)		2,450,000		-		124,668		2,325,332		72,922,411		1,721,362
Vonage		14,044,775		455,225		24,777		14,475,223		71,073,345		-
Rush Enterprises		3,200,000		-		566,794		2,633,206		67,999,349		-
Virtusa (1)		1,658,000		-		394,475		1,263,525		64,945,185		-
Knoll		3,366,000		-		845,650		2,520,350		63,084,360		674,971
SPS Commerce		1,330,000		-		389,474		940,526		61,886,611		-
GTT Communications		1,950,000		651,000		98,912		2,502,088		59,724,841		-
ESCO Technologies		1,948,000		-		459,000		1,489,000		55,703,490		238,240
Navigant Consulting		4,128,523		-		1,087,061		3,041,462		45,226,540		-
Terreno Realty		2,150,000		-		1,319		2,148,681		42,329,016		344,000
PGT		3,592,200		-		727,000		2,865,200		41,574,052		-
Thermon		1,940,094		43,735		344,194		1,639,635		39,466,014		-
McGrath Rentcorp (1)		1,580,000		-		412,524		1,167,476		35,526,294		704,154
Hackett Group		2,903,719		-		260,674		2,643,045		35,496,094		264,305
Cavco Industries		500,000		-		44,975		455,025		34,327,086		-
World Acceptance		808,343		-		278,343		530,000		32,600,300		-
Kirkland Lake Gold		6,347,100		350,100		581,436		6,115,764		27,567,455		-
Boingo Wireless		2,800,000		100,000		172,681		2,727,319		22,527,655		-
inContact (1)		3,741,000		-		1,496,103		2,244,897		22,157,133		-
CAI International (1)		1,500,000		-		661,000		839,000		17,275,010		-
Liquidity Services		1,600,000		-		-		1,600,000		15,408,000		-
Gaiam		2,100,000		-		-		2,100,000		13,734,000		-
Argonaut Gold		9,014,700		-		431,784		8,582,916		11,544,675		-
ShaMaran Petroleum		28,962,000		78,599,001				107,561,001		7,965,887		-
Towerstream		4,000,000		-		224,320		3,775,680		6,758,467		-
Rubicon Technology		2,500,000		-		128,845		2,371,155		5,761,907		-
Petromanas		67,500,000		-		3,206,000		64,294,000		2,831,201		-
Canadian Overseas Petroleum		32,515,500		-		-		32,515,500		2,055,757		-
Allied Nevada Gold (1)		7,103,513		-		7,103,513		-		-		-
Amber Road (1)		2,000,000		-		2,000,000		-		-		-
Audience (1)		2,150,000		-		2,150,000		-		-		-
Boulder Brands (1)		3,484,000		-		3,484,000		-		-		-
E2Open (1)		2,575,000		-		2,575,000		-		-		-
Marlin Business Services (1)		902,210		-		902,210		-		-		-
Petrodorado Energy (1)		2,600,000		-		2,600,000		-		-		-
RGS Energy (1)		5,000,000		-		5,000,000		-		-		-
Synageva BioPharma (1)		2,419,209		-		2,419,209		-		-		-
Total of Affiliated Transactions		285,437,636		82,731,761		47,992,553		320,176,844	$	2,510,608,886	$	12,817,213

(1) At June 30, 2015, 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, 2015, was $1,156,736,525 and $1,926,769,533, respectively. Investments in affiliated companies represented 16.28% of the Fund's total net assets at June 30, 2015.

(c) All or a portion of this security was on loan at June 30, 2015. The total market value of securities on loan at June 30, 2015 was $205,238,253.

(d) Illiquid security.

See accompanying notes to financial statements.

> Notes to Statement of Investments

(e) Denotes a restricted security, which is subject to restrictions on resale under federal securities laws. These securities are valued at fair value determined in good faith under consistently applied procedures established by the Fund's Board of Trustees. At June 30, 2015, the market value of these securities amounted to $13,207,435, which represented 0.11% of total net assets. Additional information on these securities is as follows:

Security	Acquisition Dates	Shares/Units		Cost		Value
Union Agriculture Group	12/8/10-6/27/12		1,306,818	$	15,000,000	$	12,336,362
Canadian Overseas Petroleum	11/24/10		8,400,000		3,591,152		511,129
MicroDose Therapeutx Contingent Value Rights	8/14/13		359,944		-		359,944
				$	18,591,152	$	13,207,435

(f) On June 30, 2015, the market value of foreign securities represented 2.32% of total net assets. The Fund's foreign portfolio was diversified as follows:

Country	Value		Percentage of Net Assets
Canada	$	170,746,965		1.45
Netherlands		46,521,249		0.39
Israel		37,011,600		0.31
Uruguay		12,336,362		0.10
Iraq		7,965,887		0.07
Total Foreign Portfolio	$	274,582,063		2.32

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

(h) At June 30, 2015, for federal income tax purposes, the cost of investments was approximately $7,041,239,113 and net unrealized appreciation was $5,047,063,323 consisting of gross unrealized appreciation of $5,338,831,371 and gross unrealized depreciation of $291,768,048.

Fair Value Measurements

Various inputs are used in determining the value of the Fund's investments, following the input prioritization hierarchy established by accounting principles generally accepted in the United States of America (GAAP). These inputs are summarized in the three broad levels listed below:

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

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

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

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

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

The Committee is responsible for applying the Trust's Portfolio Pricing Policy and the CWAM pricing procedures (the Policies), which are approved by and subject to the oversight of the Board.

The Committee meets as necessary, and no less frequently than quarterly, to determine fair values for securities for which market quotations are not readily available or for which CWAM believes that available market quotations are unreliable. The Committee also reviews the continuing appropriateness of the Policies. In circumstances where a security has been fair valued, the Committee will also review the continuing appropriateness of the current value of the security. The Policies address, among other things: circumstances under which market quotations will be deemed readily available; selection of third party pricing vendors; appropriate pricing methodologies; events that require fair valuation and fair value techniques; circumstances under which securities will be deemed to pose a potential for stale pricing, including when securities are illiquid, restricted, or in default; and certain delegations of authority to determine fair values to the Fund's investment manager. The Committee may also meet to discuss additional valuation matters, which may include review of back-testing results, review of time-sensitive information or approval of other valuation related actions, and to review the appropriateness of the Policies.

For investments categorized as Level 3, the significant unobservable inputs used in the fair value measurement of the Fund's securities may include: (i) data specific to the issuer or comparable issuers, (ii) general market or specific sector news and (iii) quoted prices and specific or similar security transactions. The Committee considers this data and any changes from prior periods in order to assess the reasonableness of observable and unobservable inputs, any assumptions or internal models used to value those securities and changes in fair value. Significant changes in any of these factors could result in lower or higher fair value measurements. Various factors impact the frequency of monitoring (which may occur as often as daily), however the Committee may determine that changes to inputs, assumptions and models are not required with the same frequency.

See accompanying notes to financial statements.

COLUMBIA ACORN® FUND

STATEMENT OF INVESTMENTS (UNAUDITED), CONTINUED

> Notes to Statement of Investments

The following table summarizes the inputs used, as of June 30, 2015, in valuing the Fund's assets:

Investment Type	Quoted Prices (Level 1)		Other Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Equities
Information	$	3,085,765,485	$	-	$	-	$	3,085,765,485
Industrial Goods & Services		2,598,618,430		-		-		2,598,618,430
Finance		1,450,096,183		-		-		1,450,096,183
Health Care		1,440,406,633		-		359,944		1,440,766,577
Consumer Goods & Services		1,371,844,447		-		-		1,371,844,447
Other Industries		683,017,641		-		-		683,017,641
Energy & Minerals		439,129,786		511,129		12,336,362		451,977,277
Total Equities		11,068,878,605		511,129		12,696,306		11,082,086,040
Total Short-Term Investments		800,578,010		-		-		800,578,010
Total Securities Lending Collateral		205,638,386		-		-		205,638,386
Total Investments	$	12,075,095,001	$	511,129	$	12,696,306	$	12,088,302,436

There were no transfers of financial assets between levels during the period.

The Fund does not hold any significant investments (greater than one percent of net assets) categorized as Level 3.

Certain securities classified as Level 3 are valued by the Committee at fair value, using a market approach, as determined in good faith under consistently applied procedures established by and under the general supervision of the Board. To determine fair value for these securities, for which no market exists, the Committee utilizes the valuation technique it deems most appropriate in the circumstances, using some unobservable inputs, which may include, but are not limited to estimated earnings of the company and the position of the security within the company's capital structure. The Committee also may use some observable inputs, which may include, but are not limited to, trades of similar securities and market multiples derived from a set of comparable companies. Significant increases or decreases to any of these inputs could result in a significantly lower or higher fair value measurement.

See accompanying notes to financial statements.

COLUMBIA ACORN INTERNATIONAL®

MAJOR PORTFOLIO CHANGES IN THE SECOND QUARTER (UNAUDITED)

	Number of Shares
	3/31/15		6/30/15
Purchases
Asia
> Japan
Aeon Mall		2,710,000		3,000,000
Aica Kogyo		1,012,000		1,237,000
Aozora Bank		8,340,000		10,440,000
Asahi Intecc		0		105,400
Cocokara Fine		0		68,100
Disco		292,400		343,400
Dowa Holdings		0		2,600,000
Glory		1,798,600		1,840,000
IHI		4,235,000		7,100,000
Nihon Parkerizing		1,753,060		1,822,292
Nippon Paint Holdings		624,000		915,000
Otsuka		629,900		641,900
Santen Pharmaceutical		2,728,000		2,911,000
> Taiwan
Advantech		3,034,686		3,054,686
Delta Electronics		3,761,000		6,351,000
Far EasTone Telecom		14,140,000		17,600,000
Largan Precision		293,000		399,000
Lite-On Technology		10,016,881		16,430,881
Novatek Microelectronics		5,871,000		8,126,000
Silergy		0		820,000
Vanguard International Semiconductor		13,516,000		27,141,000
Voltronic Power		1,000,000		1,519,000
> China
51job - ADR		0		375,000
CAR Inc		0		27,000,000
China Everbright International		28,645,000		29,650,000
Chongqing Rural Commercial Bank		0		40,167,000
Jiangnan Group		0		102,280,000
NewOcean Energy		32,790,000		48,234,000
Phoenix Healthcare Group		0		11,984,000
Shanghai Industrial		0		8,673,000
TravelSky Technology		0		14,556,000
> Korea
CJ Hellovision		578,438		2,908,469
Hyundai Marine & Fire Insurance		0		444,715
KCC		0		65,494
Koh Young Technology		0		43,923
> India
Amara Raja		0		519,553
Container Corporation of India		1,204,602		1,382,783
> Singapore
China Everbright Water		0		28,242,100
SIIC Environment		0		165,731,200

	Number of Shares
	3/31/15		6/30/15
> Hong Kong
Mapletree Greater China Commercial Trust		52,849,000		63,364,000
Samsonite International		0		12,000,000
Vitasoy International		9,347,000		9,675,000
> Indonesia
Matahari Department Store		19,000,000		24,195,600
Surya Citra Media		11,854,300		61,947,300
Philippines
Universal Robina		3,106,980		5,900,000
> Malaysia
Astro Malaysia Holdings		410,300		19,000,000
Europe
> United Kingdom
Halfords		4,372,390		4,712,000
Regus		0		8,840,000
Rightmove		872,000		1,009,000
WH Smith		2,430,000		2,638,000
> Sweden
Recipharm		979,403		1,205,000
Swedish Match		856,000		967,247
> Germany
Elringklinger		745,000		885,000
> Denmark
William Demant Holding		0		700,000
> Netherlands
Arcadis		790,670		849,025
> France
Eutelsat		1,110,000		1,445,000
Saft		729,096		745,310
> Finland
Konecranes		711,000		1,103,420
> Italy
Hera		0		4,213,201
Industria Macchine Automatiche		385,950		459,000
Other Countries
> Australia
Spotless		46,578,144		47,446,000
> Egypt
Commercial International Bank of Egypt		3,119,000		5,963,570
Latin America
> Brazil
Odontoprev		6,487,000		7,000,000
> Mexico
Grupo Aeroportuario del Sureste - ADR		252,000		283,000
Qualitas		12,339,000		13,215,000

See accompanying notes to financial statements.

COLUMBIA ACORN INTERNATIONAL®

MAJOR PORTFOLIO CHANGES IN THE SECOND QUARTER (UNAUDITED), CONTINUED

	Number of Shares
	3/31/15		6/30/15
Sales
Asia
> Japan
Omron		512,000		0
Makita		258,000		0
Aeon Financial Service		1,600,000		1,400,000
Ariake Japan		876,300		833,800
Benesse		1,301,200		987,200
Daiseki		1,580,000		1,270,000
Ezaki Glico		746,500		655,500
Japan Airport Terminal		600,000		550,000
Kansai Paint		2,978,600		1,692,600
Nakanishi		643,000		580,000
NGK Insulators		2,700,000		2,400,000
Nippon Kayaku		3,143,000		3,111,000
Nippon Shokubai		2,066,000		1,502,000
OBIC		772,000		665,000
Park24		1,960,000		1,678,000
Rohto Pharmaceutical		1,676,000		0
Suruga Bank		1,470,000		1,270,000
Toto		2,000,000		1,550,000
Toyo Suisan Kaisha		370,900		0
> Taiwan
Chroma Ate		7,611,000		3,061,000
Hermes Microvision		211,750		0
PChome Online		2,300,000		2,124,346
> China
Sino Biopharmaceutical		23,671,000		19,730,000
> Korea
CJ Corp		249,671		215,971
KT&G		536,317		478,317
LS Industrial Systems		631,865		494,303
> India
Asian Paints		3,423,265		0
Bosch		90,000		0
> Singapore
Ascendas REIT		13,500,000		0
CDL Hospitality Trust		17,742,000		7,795,600
Mapletree Commercial Trust		55,000,000		50,000,000
Mapletree Industrial Trust		15,000,000		10,502,000
Mapletree Logistics Trust		20,865,750		13,847,750
> Hong Kong
Kingboard Chemicals		4,358,000		0
Lifestyle International		13,120,000		8,099,500
Melco Crown Entertainment - ADR		1,800,000		1,130,000
Sa Sa International		25,223,000		0
> Indonesia
Ace Indonesia		324,290,000		312,000,000
Mayora Indah		6,000,000		3,993,900
Tower Bersama Infrastructure		33,000,000		31,000,000

	Number of Shares
	3/31/15		6/30/15
> Philippines
Robinsons Retail Holdings		16,000,000		13,500,000
> Malaysia
7-Eleven Malaysia Holdings		43,839,000		41,700,000
Aeon		17,441,500		0
Europe
> United Kingdom
Abcam		4,800,000		4,440,000
Babcock International		3,300,000		1,568,000
RPS Group		5,800,000		0
Whitbread		473,398		0
> Sweden
Sweco		3,255,024		2,925,024
> France
Hi-Media		1,831,204		0
Norbert Dentressangle		163,400		0
> Spain
Bolsas y Mercados Españoles		830,000		535,000
Viscofan		671,000		379,000
> Switzerland
Geberit		179,000		116,500
> Italy
Pirelli		1,909,000		0
> Belguim
EVS Broadcast Equipment		516,965		450,656
Other Countries
> Canada
CCL Industries		800,772		651,772
Granite Oil		1,496,551		376,629
> Australia
Challenger Financial		12,550,000		6,170,000
Domino's Pizza Enterprises		2,428,257		2,123,737
> South Africa
Mr. Price		2,644,083		0
Naspers		493,188		142,892
Northam Platinum		8,679,940		8,665,223
Rand Merchant Insurance		19,045,300		16,575,943
> United States
Synageva BioPharma		350,000		0
Textainer Group Holdings		933,297		440,152

See accompanying notes to financial statements.

COLUMBIA ACORN INTERNATIONAL®

STATEMENT OF INVESTMENTS (UNAUDITED), JUNE 30, 2015

Number of Shares			Value
			Equities: 95.0%
Asia 48.6%
		> Japan 21.4%
	2,400,000	NGK Insulators	$	61,754,562
		Ceramic Products for Auto, Power & Electronics
	3,000,000	Aeon Mall		56,177,319
		Suburban Shopping Mall Developer, Owner & Operator
	1,840,000	Glory		54,434,934
		Currency Handling Systems & Related Equipment
	1,050,000	FamilyMart		48,284,413
		Convenience Store Operator
	3,600,000	Ushio		46,859,844
		Industrial Light Sources
	2,911,000	Santen Pharmaceutical		41,186,944
		Specialty Pharma (Ophthalmic Medicine)
	28,000	Orix JREIT		40,328,910
		Diversified REIT
	930,000	JIN (a)		40,086,843
		Eyeglasses Retailer
	1,440,000	NGK Spark Plug		39,879,625
		Automobile Parts
	276,620	Hirose Electric		39,633,751
		Electrical Connectors
	4,938,000	NOF		39,615,966
		Specialty Chemicals, Life Science & Rocket Fuels
	10,440,000	Aozora Bank		39,390,270
		Commercial Bank
	1,400,000	Aeon Financial Service		38,842,347
		Diversified Consumer-related Finance Company in Japan
	1,225,000	Recruit Holdings		37,355,472
		Recruitment & Media Services
	774,400	Kintetsu World Express		34,753,252
		Airfreight Logistics
	833,800	Ariake Japan		34,121,552
		Commercial Soup & Sauce Extracts
	3,111,000	Nippon Kayaku		33,540,496
		Functional Chemicals, Pharmaceuticals & Auto Safety Systems
	7,100,000	IHI		33,058,830
		Industrial Conglomerates
	655,500	Ezaki Glico		32,553,977
		Confectionary, Ice Cream & Dairy Products
	1,440,000	OSG		30,867,635
		Consumable Cutting Tools
	6,149	Kenedix Office Investment		30,799,306
		Tokyo Mid-size Office REIT
	2,736,000	Moshi Moshi Hotline		30,613,337
		Call Center Operator
	641,900	Otsuka		29,964,939
		One-stop IT Services & Office Supplies Provider
	550,000	Japan Airport Terminal		29,934,058
		Airport Terminal Operator at Haneda
	665,000	OBIC		29,647,517
		Computer Software

Number of Shares			Value
	1,402,000	Tamron (b)	$	29,588,201
		Camera Lenses
	1,237,000	Aica Kogyo		28,734,121
		Laminated Sheets, Building Materials & Chemical Adhesives
	1,678,000	Park24		28,726,486
		Parking Lot Operator
	343,400	Disco		28,388,467
		Semiconductor Dicing & Grinding Equipment
	1,600,000	Doshisha		28,371,416
		Consumer Goods Wholesaler
	1,550,000	Toto		27,937,018
		Toilets & Bathroom Fittings
	1,950,000	Misumi Group		27,683,587
		Industrial Components Distributor
	1,270,000	Suruga Bank		27,204,839
		Regional Bank
	1,692,600	Kansai Paint		26,223,796
		Paint Producer in Japan, India, China & Southeast Asia
	915,000	Nippon Paint Holdings		25,785,258
		Paints for Automotive, Decorative & Industrial Usage
	1,020,000	Nabtesco		25,585,412
		Machinery Components
	987,200	Benesse		24,748,518
		Education Service Provider
	2,600,000	Dowa Holdings		24,570,606
		Environmental/Recycling, Nonferrous Metals, Electric Material & Metal Processing
	1,270,000	Daiseki		24,566,764
		Waste Disposal & Recycling
	309,000	Rinnai		24,332,239
		Gas Appliances for Home & Commercial Use
	822,700	Hamamatsu Photonics		24,259,066
		Optical Sensors for Medical & Industrial Applications
	12,050	Japan Retail Fund		24,096,254
		Retail REIT in Japan
	682,800	Kaken Pharmaceutical		23,837,563
		Pharmaceutical & Agrochemical Producer
	1,107,000	Stanley Electric		23,055,295
		Automobile Lighting & LED Equipment
	5,092	Industrial & Infrastructure Fund		22,993,242
		Industrial REIT in Japan
	390,000	Hoshizaki Electric		22,939,588
		Commercial Kitchen Equipment
	580,000	Nakanishi		22,915,296
		Dental Tools & Machinery
	698,480	Milbon		22,226,065
		Hair Products for Salons
	1,914,500	Asahi Diamond Industrial		21,569,614
		Consumable Diamond Tools
	313,200	Hikari Tsushin		21,109,057
		Office IT/Mobiles/Insurance Distribution
	1,502,000	Nippon Shokubai		20,545,926
		Producer of Acrylic Acid & Super Absorbent Polymers Used in Disposable Diapers

See accompanying notes to financial statements.

COLUMBIA ACORN INTERNATIONAL®

STATEMENT OF INVESTMENTS (UNAUDITED), CONTINUED

Number of Shares			Value
		> Japan—continued
	771,000	Icom (b)	$	19,416,989
		Two Way Radio Communication Equipment
	1,822,292	Nihon Parkerizing		18,484,348
		Metal Surface Treatment Chemicals & Processing Service
	352,600	MonotaRO		15,478,331
		Online Maintenance, Repair & Operations Goods Distributor in Japan
	105,400	Asahi Intecc		7,221,100
		Medical Guidewires for Surgery
	68,100	Cocokara Fine		2,342,643
		Drugstores
				1,688,623,204
		> Taiwan 5.5%
	9,100,000	President Chain Store		63,977,061
		Convenience Chain Store Operator in Taiwan
	399,000	Largan Precision		45,546,177
		Mobile Device Camera Lenses & Modules
	27,141,000	Vanguard International Semiconductor		43,312,321
		Semiconductor Foundry
	17,600,000	Far EasTone Telecom		42,543,202
		Mobile Operator in Taiwan
	8,126,000	Novatek Microelectronics		39,194,777
		Display Related Integrated Circuit Designer
	2,124,346	PChome Online		35,066,912
		Taiwanese Internet Retail Company
	2,081,000	St. Shine Optical		33,078,861
		Disposable Contact Lens Original Equipment Manufacturer
	6,351,000	Delta Electronics		32,490,893
		Industrial Automation, Switching Power Supplies & Passive Components
	1,925,000	Ginko International		24,194,974
		Contact Lens Maker in China
	3,054,686	Advantech		20,974,520
		Industrial PC & Components
	16,430,881	Lite-On Technology		19,277,247
		Mobile Device, LED & PC Server Component Supplier
	1,519,000	Voltronic Power		19,144,351
		Uninterruptible Power Supply Products
	820,000	Silergy		8,446,176
		Chinese Provider of Analog & Mixed Digital Integrated Circuits
	3,061,000	Chroma Ate		6,765,020
		Automatic Test Systems, Testing & Measurement Instruments
				434,012,492
		> China 5.4%
	27,000,000	CAR Inc (c)		57,380,915
		Consolidator of Chinese Auto Rental Sector
	29,650,000	China Everbright International		53,103,100
		Municipal Waste Operator
	90,360,000	Sihuan Pharmaceuticals (d)		40,813,582
		Chinese Generic Drug Manufacturer

Number of Shares			Value
	40,167,000	Chongqing Rural Commercial Bank	$	32,128,392
		Rural Commercial Bank
	760,000	WuXi PharmaTech - ADR (c)		32,117,600
		Contract Research Organization in China
	102,280,000	Jiangnan Group		29,387,362
		Cable & Wire Manufacturer
	8,673,000	Shanghai Industrial		29,365,135
		Shanghai State Owned Enterprise
	560,388	BitAuto - ADR (c)		28,607,808
		Automotive Information Website for Buyers & Dealers
	47,500,000	AMVIG Holdings (b)		24,511,227
		Chinese Tobacco Packaging Material Supplier
	19,730,000	Sino Biopharmaceutical		22,874,405
		Pharmaceutical Developer
	11,984,000	Phoenix Healthcare Group		22,795,729
		Private Hospital Management Group
	48,234,000	NewOcean Energy		22,388,210
		Southern China Liquefied Petroleum Gas Distributor
	14,556,000	TravelSky Technology		21,412,133
		Chinese Air Travel Transaction Processor
	375,000	51job - ADR (a)(c)		12,465,000
		Integrated Human Resource Services
				429,350,598
		> Korea 3.7%
	215,971	CJ Corp		57,218,066
		Holding Company of Korean Consumer Conglomerate
	478,317	KT&G		40,694,144
		Tobacco & Ginseng Products
	145,900	Nongshim		37,941,772
		Instant Noodles, Snacks & Bottled Water
	2,908,469	CJ Hellovision		33,369,816
		Cable TV, Broadband & Mobile Virtual Network Operator
	1,119,428	LF Corp		30,365,821
		Apparel Design & Retail
	65,494	KCC		28,819,139
		Paint & Housing Material Manufacturer
	494,303	LS Industrial Systems		20,222,385
		Electrical & Automation Equipment
	1,187,900	Cheil Worldwide (c)		18,389,280
		Advertising
	475,576	Grand Korea Leisure (a)		13,259,594
		'Foreigner Only' Casino Group in Korea
	444,715	Hyundai Marine & Fire Insurance		11,747,308
		Property & Casualty Insurance
	43,923	Koh Young Technology		1,616,573
		Inspection Systems for Printed Circuit Boards
				293,643,898
		> India 3.2%
	13,478,000	Zee Entertainment Enterprises		77,791,018
		Indian Programmer of Pay Television Content
	6,229,667	Bharti Infratel		43,728,975
		Communications Towers

See accompanying notes to financial statements.

Number of Shares			Value
		> India—continued
	1,382,783	Container Corporation of India	$	36,369,661
		Railway Cargo Services
	920,000	Colgate Palmolive India		29,443,867
		Consumer Products in Oral Care
	6,095,000	Adani Ports & Special Economic Zone		29,416,788
		Indian West Coast Shipping Port
	1,850,000	United Breweries		27,087,202
		Indian Brewer
	519,553	Amara Raja		7,193,649
		Indian Maker of Auto & Industrial Batteries, Mostly for the Replacement Market
				251,031,160
		> Singapore 2.8%
	11,000,000	Singapore Exchange		63,900,636
		Singapore Equity & Derivatives Market Operator
	50,000,000	Mapletree Commercial Trust		54,373,910
		Retail & Office Property Landlord
	165,731,200	SIIC Environment (c)		23,976,605
		Waste Water Treatment Operator
	8,500,000	Petra Foods		22,088,577
		Chocolate Manufacturer in Southeast Asia
	28,242,100	China Everbright Water (c)		20,664,322
		Waste Water Treatment Operator
	10,502,000	Mapletree Industrial Trust		12,165,563
		Industrial Property Landlord
	13,847,750	Mapletree Logistics Trust		11,618,189
		Industrial Property Landlord
	7,795,600	CDL Hospitality Trust		9,434,479
		Hotel Owner Operator
				218,222,281
		> Hong Kong 2.1%
	63,364,000	Mapletree Greater China Commercial Trust		47,967,609
		Retail & Office Property Landlord
	12,000,000	Samsonite International		41,430,891
		Mass Market Luggage & Travel Accessories
	1,130,000	Melco Crown Entertainment - ADR (a)		22,181,900
		Macau Casino Operator
	15,000,000	Melco International		21,177,446
		Macau Casino Operator
	9,675,000	Vitasoy International		16,475,415
		Hong Kong Soy Food Brand
	8,099,500	Lifestyle International		15,025,486
		Mid- to High-end Department Store Operator in Hong Kong & China
				164,258,747
		> Indonesia 1.5%
	24,195,600	Matahari Department Store		29,987,974
		Department Store Chain in Indonesia
	31,000,000	Tower Bersama Infrastructure		21,449,466
		Communications Towers
	50,000,000	Link Net (c)		19,032,439
		Fixed Broadband & Cable TV Service Provider

Number of Shares			Value
	312,000,000	Ace Indonesia	$	15,078,048
		Home Improvement Retailer
	61,947,300	Surya Citra Media		13,331,907
		Free to Air TV Station in Indonesia
	220,150,800	Arwana Citramulia		8,751,541
		Ceramic Tiles for Home Decoration
	3,993,900	Mayora Indah		7,784,014
		Consumer Branded Food Manufacturer
	54,631,700	MNC Sky Vision (c)		5,941,569
		Satellite Pay TV Operator in Indonesia
				121,356,958
		> Philippines 1.1%
	35,000,000	Puregold Price Club		28,705,730
		Supermarket Operator in the Philippines
	5,900,000	Universal Robina		25,368,880
		Branded Consumer Food Manufacturer in the Philippines
	13,500,000	Robinsons Retail Holdings		22,290,419
		Multi-format Retailer in the Philippines
	90,000,000	Melco Crown (Philippines) Resorts (c)		10,215,102
		Integrated Resort Operator in Manila
				86,580,131
		> Thailand 1.0%
	4,360,000	Airports of Thailand		39,026,289
		Airport Operator of Thailand
	114,913,600	Home Product Center		22,924,221
		Home Improvement Retailer
	14,485,000	Robinson Department Store		19,163,300
		Department Store Operator in Thailand
				81,113,810
		> Cambodia 0.5%
	55,000,000	Nagacorp		40,491,993
		Casino & Entertainment Complex in Cambodia
		> Malaysia 0.4%
	41,700,000	7-Eleven Malaysia Holdings		17,683,541
		Exclusive 7-Eleven Franchisor for Malaysia
	19,000,000	Astro Malaysia Holdings		15,505,254
		Pay TV Operator in Malaysia
				33,188,795
Asia: Total				3,841,874,067
Europe 30.0%
		> United Kingdom 10.1%
	1,253,571	Spirax Sarco		66,831,015
		Steam Systems for Manufacturing & Process Industries
	2,638,000	WH Smith		63,334,946
		Newsprint, Books & General Stationery Retailer
	1,009,000	Rightmove		51,953,268
		Internet Real Estate Listings
	45,000,000	Cable and Wireless		47,090,359
		Telecommunications Service Provider in the Caribbean

See accompanying notes to financial statements.

COLUMBIA ACORN INTERNATIONAL®

STATEMENT OF INVESTMENTS (UNAUDITED), CONTINUED

Number of Shares			Value
		> United Kingdom—continued
	1,980,000	Aggreko	$	44,768,366
		Temporary Power & Temperature Control Services
	2,540,000	Jardine Lloyd Thompson Group		41,665,776
		International Business Insurance Broker
	4,712,000	Halfords		39,091,692
		UK Retailer of Leisure Goods & Auto Parts
	8,840,000	Regus		36,280,286
		Rental of Office Space in Full Service Business Centers
	4,440,000	Abcam		36,137,491
		Online Sales of Antibodies
	958,646	Fidessa Group		34,267,698
		Software for Financial Trading Systems
	39,805,000	Assura		34,242,622
		UK Primary Health Care Property Developer
	4,712,000	Ocado (c)		33,013,230
		Online Grocery Retailer
	2,725,000	Halma		32,626,219
		Health & Safety Sensor Technology
	2,660,000	Domino's Pizza UK & Ireland		32,474,907
		Pizza Delivery in the UK, Ireland & Germany
	14,379,428	Connect Group (b)		32,026,534
		Newspaper & Magazine Distributor
	7,430,000	Polypipe		31,695,960
		Manufacturer of Plastic Piping & Fittings
	1,568,000	Babcock International		26,608,174
		Public Sector Outsourcer
	908,500	AVEVA		25,808,848
		Engineering Software
	5,650,001	Elementis		22,779,828
		Specialty Chemicals
	1,280,000	Smith & Nephew		21,600,287
		Medical Equipment & Supplies
	1,480,000	Shaftesbury		20,184,905
		London Prime Retail REIT
	3,075,000	PureCircle (a)(c)		19,567,953
		Natural Sweeteners
				794,050,364
		> Sweden 3.3%
	1,666,208	Hexagon		60,378,521
		Design, Measurement & Visualization Software & Equipment
	948,422	Unibet		57,775,848
		European Online Gaming Operator
	2,925,024	Sweco (a)		38,371,787
		Engineering Consultants
	1,137,000	Modern Times Group (a)		30,503,423
		Nordic TV Broadcaster
	967,247	Swedish Match		27,512,783
		Swedish Snus
	1,044,000	Mekonomen		25,502,271
		Nordic Integrated Wholesaler/Retailer of Automotive Parts & Service
	1,205,000	Recipharm		22,530,564
		Contract Development Manufacturing Organization
				262,575,197

Number of Shares			Value
		> Germany 3.2%
	608,000	MTU Aero Engines	$	57,188,394
		Airplane Engine Components & Services
	1,350,000	Wirecard (a)		51,698,362
		Online Payment Processing & Risk Management
	117,000	Rational		42,972,601
		Commercial Ovens
	795,000	NORMA Group		40,189,519
		Clamps for Automotive & Industrial Applications
	795,000	Aurelius		33,985,381
		European Turnaround Investor
	885,000	Elringklinger		23,792,869
		Automobile Components
				249,827,126
		> Denmark 2.4%
	1,932,063	SimCorp		76,942,989
		Software for Investment Managers
	1,315,800	Novozymes		62,546,658
		Industrial Enzymes
	700,000	William Demant Holding (c)		53,400,380
		Manufacture & Distribution of Hearing Aids & Diagnostic Equipment
				192,890,027
		> Netherlands 2.4%
	2,103,770	Aalberts Industries		62,481,112
		Flow Control & Heat Treatment
	718,124	Vopak		36,239,170
		Operator of Petroleum & Chemical Storage Terminals
	324,700	Gemalto (a)		28,915,893
		Digital Security Solutions
	1,201,000	Brunel (a)		23,826,337
		Temporary Specialist & Energy Staffing
	849,025	Arcadis		23,351,022
		Engineering Consultants
	114,395	Core Labs (a)		13,045,606
		Oil & Gas Reservoir Consulting
				187,859,140
		> France 2.0%
	1,350,000	Neopost		58,087,286
		Postage Meter Machines
	1,445,000	Eutelsat		46,637,223
		Fixed Satellite Services
	745,310	Saft		29,081,799
		Niche Battery Manufacturer
	90,000	Eurofins Scientific (a)		27,401,888
		Food, Pharmaceuticals & Materials Screening & Testing
				161,208,196
		> Spain 2.0%
	10,110,000	Distribuidora Internacional de Alimentación		77,207,235
		Discount Retailer in Spain & Latin America
	6,564,000	Prosegur		36,003,933
		Security Guards
	379,000	Viscofan		22,922,144
		Sausage Casings Maker

See accompanying notes to financial statements.

Number of Shares			Value
		> Spain—continued
	535,000	Bolsas y Mercados Españoles	$	21,639,007
		Spanish Stock Markets
				157,772,319
		> Switzerland 1.6%
	213,500	Partners Group		63,825,071
		Private Markets Asset Management
	116,500	Geberit		38,839,563
		Plumbing Systems
	72,500	INFICON		24,775,389
		Gas Detection Instruments
				127,440,023
		> Finland 1.2%
	1,669,000	Tikkurila		33,175,995
		Decorative & Industrial Paint in Scandinavia, Central & Eastern Europe
	1,103,420	Konecranes		32,143,749
		Manufacture & Service of Industrial Cranes & Port Handling Equipment
	7,766,000	Sponda		28,657,721
		Office, Retail & Logistics Properties
				93,977,465
		> Norway 0.6%
	3,529,000	Orkla		27,771,276
		Food & Brands, Aluminum, Chemicals Conglomerate
	2,613,864	Atea		23,336,732
		Nordic IT Hardware/Software Reseller & Integrator
				51,108,008
		> Kazakhstan 0.6%
	5,143,000	Halyk Savings Bank of Kazakhstan - GDR		43,715,500
		Retail Bank & Insurer in Kazakhstan
		> Italy 0.4%
	459,000	Industria Macchine Automatiche		21,389,727
		Food & Drugs Packaging & Machinery
	4,213,201	Hera		10,540,259
		Northern Italian Utility
				31,929,986
		> Belgium 0.2%
	450,656	EVS Broadcast Equipment		13,062,755
		Digital Live Mobile Production Software & Systems
Europe: Total				2,367,416,106
Other Countries 13.7%
		> Canada 4.4%
	651,772	CCL Industries		79,945,132
		Global Label Converter
	898,000	Vermilion Energy (a)		38,788,711
		Canadian Exploration & Production Company
	3,188,000	CAE		37,954,812
		Flight Simulator Equipment & Training Centers
	1,067,730	ShawCor		31,279,616
		Oil & Gas Pipeline Products
	490,200	Onex Capital		27,123,877
		Private Equity

Number of Shares			Value
	2,115,898	Rona	$	25,716,038
		Canadian Home Improvement Retailer
	1,010,000	PrairieSky Royalty		25,464,291
		Canadian Owner of Oil & Gas Mineral Interests
	726,000	Keyera (a)		24,238,751
		Integrated Supply of Hydrocarbon Processing, Transport & Storage
	1,358,857	Baytex (a)		21,138,984
		Oil & Gas Producer in Canada
	537,943	Ag Growth		20,169,632
		Manufacturer of Augers & Grain Handling Equipment
	2,245,052	Boulder Energy (c)		14,919,081
		Canadian Exploration & Production
	376,629	Granite Oil		1,896,715
		Canadian Oil & Gas Producer
				348,635,640
		> Australia 3.3%
	47,446,000	Spotless		76,374,145
		Facility Management & Catering Company
	2,123,737	Domino's Pizza Enterprises		58,320,313
		Domino's Pizza Operator in Australia & New Zealand
	4,270,000	Amcor		45,123,234
		Global Leader in Flexible & Rigid Packaging
	6,170,000	Challenger Financial		31,982,776
		Annuity Provider in Australia
	4,900,000	Estia Health (c)		22,683,575
		Residential Aged Care Operator
	5,260,000	IAG		22,614,715
		General Insurance Provider
	1,070,000	Austbrokers		7,430,028
		Local Australian Small Business Insurance Broker
				264,528,786
		> South Africa 2.5%
	13,683,594	Coronation Fund Managers		92,689,872
		South African Fund Manager
	16,575,943	Rand Merchant Insurance		57,864,565
		Directly Sold Property & Casualty Insurance; Holdings in other Insurers
	8,665,223	Northam Platinum (c)		28,675,150
		Platinum Mining in South Africa
	142,892	Naspers		22,257,138
		Media in Africa, China, Russia & other Emerging Markets
				201,486,725
		> United States 1.2%
	350,000	Cimarex Energy		38,608,500
		Oil & Gas Producer in Texas, New Mexico & Oklahoma
	912,000	Bladex		29,348,160
		Latin American Trade Financing House
	634,500	Hornbeck Offshore (a)(c)		13,026,285
		Supply Vessel Operator in Gulf of Mexico
	440,152	Textainer Group Holdings (a)		11,448,354
		Top International Container Leasor
				92,431,299

See accompanying notes to financial statements.

COLUMBIA ACORN INTERNATIONAL®

STATEMENT OF INVESTMENTS (UNAUDITED), CONTINUED

Number of Shares			Value
		> New Zealand 1.0%
	10,800,000	Auckland International Airport	$	36,146,416
		Auckland Airport Operator
	8,000,000	Sky City Entertainment		22,761,597
		Casino & Entertainment Complex
	4,011,000	Ryman Healthcare		21,527,161
		Retirement Village Operator
				80,435,174
		> Israel 0.7%
	791,000	Caesarstone		54,215,140
		Quartz Countertops
		> Egypt 0.6%
	5,963,570	Commercial International Bank of Egypt		43,753,008
		Private Universal Bank in Egypt
Other Countries: Total				1,085,485,772
Latin America 2.7%
		> Brazil 1.0%
	3,500,000	Localiza Rent A Car		34,649,899
		Car Rental
	7,000,000	Odontoprev		24,383,262
		Dental Insurance
	1,400,000	Linx		21,681,515
		Retail Management Software in Brazil
				80,714,676
		> Mexico 0.8%
	283,000	Grupo Aeroportuario del Sureste - ADR		40,149,210
		Mexican Airport Operator
	13,215,000	Qualitas (c)		21,868,755
		Auto Insurer in Mexico & Central America
				62,017,965
		> Colombia 0.3%
	23,377,000	Isagen		24,945,373
		Colombian Electricity Provider
		> Guatemala 0.2%
	1,626,600	Tahoe Resources		19,717,153
		Silver & Gold Projects in Guatemala & Peru
		> Chile 0.2%
	921,000	Sociedad Quimica y Minera de Chile - ADR		14,754,420
		Producer of Specialty Fertilizers, Lithium & Iodine

Number of Shares			Value
		> Uruguay 0.2%
	1,306,818	Union Agriculture Group (c)(d)(e)	$	12,336,362
		Farmland Operator in Uruguay
Latin America: Total				214,485,949
Total Equities: 95.0% (Cost: $6,121,766,899)				7,509,261,894	(f)
Short-Term Investments 4.2%
	220,000,000	JPMorgan U.S. Government Money Market Fund, IM Shares (7 day yield of 0.01%)		220,000,000
	114,794,388	JPMorgan U.S. Government Money Market Fund, Agency Shares (7 day yield of 0.01%)		114,794,388
Total Short-Term Investments: 4.2% (Cost: $334,794,388)				334,794,388
Securities Lending Collateral 2.4%
	186,393,214	Dreyfus Government Cash Management Fund, Institutional Shares (7 day yield of 0.01%) (g)		186,393,214
Total Securities Lending Collateral: 2.4% (Cost: $186,393,214)				186,393,214
Total Investments: 101.6% (Cost: $6,642,954,501)(h)				8,030,449,496
Obligation to Return Collateral for Securities Loaned: (2.4)%				(186,393,214	)
Cash and Other Assets Less Liabilities: 0.8%				58,285,708
Net Assets: 100.0%			$	7,902,341,990

ADR - American Depositary Receipts

GDR - Global Depositary Receipts

REIT - Real Estate Investment Trust

See accompanying notes to financial statements.

> Notes to Statement of Investments

(a) All or a portion of this security was on loan at June 30, 2015. The total market value of securities on loan at June 30, 2015 was $178,244,535.

Security	Balance of Shares Held 12/31/14		Purchases/ Additions		Sales/ Reductions		Balance of Shares Held 6/30/15		Value		Dividend
Connect Group		14,379,428		-		-		14,379,428	$	32,026,534	$	2,165,486
Tamron		1,402,000		-		-		1,402,000		29,588,201		283,129
AMVIG Holdings		35,119,000		12,381,000		-		47,500,000		24,511,227		1,771,515
Icom		835,000		-		64,000		771,000		19,416,989		140,145
Total of Affiliated Transactions		51,735,428		12,381,000		64,000		64,052,428	$	105,542,951	$	4,360,275

The aggregate cost and value of these companies at June 30, 2015, was $113,439,966 and $105,542,951, respectively. Investments in affiliated companies represented 1.34% of the Fund's total net assets at June 30, 2015.

(d) Illiquid security.

(e) Denotes a restricted security, which is subject to restrictions on resale under federal securities laws. This security is valued at fair value determined in good faith under consistently applied procedures established by the Fund's Board of Trustees. At June 30, 2015, the market value of this security amounted to $12,336,362, which represented 0.16% of total net assets. Additional information on this security is as follows:

Security				Acquisition Dates				Shares/Units				Cost				Value
Union Agriculture Group				12/8/10-6/27/12					1,306,818			$	15,000,000			$	12,336,362

(f) On June 30, 2015, the Fund's total equity investments were denominated in currencies as follows:

Currency	Value		Percentage of Net Assets
Japanese Yen	$	1,688,623,204		21.4
Euro		882,591,381		11.2
British Pound		794,050,364		10.0
Hong Kong Dollar		490,761,422		6.2
Taiwan Dollar		434,012,492		5.5
Other currencies less than 5% of total net assets		3,219,223,031		40.7
Total Equities	$	7,509,261,894		95.0

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

(h) At June 30, 2015, for federal income tax purposes, the cost of investments was approximately $6,642,954,501 and net unrealized appreciation was $1,387,494,995 consisting of gross unrealized appreciation of $1,807,290,071 and gross unrealized depreciation of $419,795,076.

Fair Value Measurements

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

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

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

The Committee is responsible for applying the Trust's Portfolio Pricing Policy and the CWAM pricing procedures (the Policies), which are approved by and subject to the oversight of the Board.

See accompanying notes to financial statements.

COLUMBIA ACORN INTERNATIONAL®

STATEMENT OF INVESTMENTS (UNAUDITED), CONTINUED

> Notes to Statement of Investments

The following table summarizes the inputs used, as of June 30, 2015, in valuing the Fund's assets:

Investment Type	Quoted Prices (Level 1)		Other Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Equities
Asia	$	95,372,308	$	3,705,688,177	$	40,813,582	$	3,841,874,067
Europe		13,045,606		2,354,370,500		-		2,367,416,106
Other Countries		495,282,079		590,203,693		-		1,085,485,772
Latin America		202,149,587		-		12,336,362		214,485,949
Total Equities		805,849,580		6,650,262,370		53,149,944		7,509,261,894
Total Short-Term Investments		334,794,388		-		-		334,794,388
Total Securities Lending Collateral		186,393,214		-		-		186,393,214
Total Investments	$	1,327,037,182	$	6,650,262,370	$	53,149,944	$	8,030,449,496

The Fund's assets assigned to the Level 2 input category are generally valued using a market approach, in which a security's value is determined through its correlation to prices and information from observable market transactions for similar or identical assets. Foreign equities are generally valued at the last sale price on the foreign exchange or market on which they trade. The Fund may use a statistical fair valuation model, in accordance with the policy adopted by the Board, provided by an independent third party to value securities principally traded in foreign markets in order to adjust for possible stale pricing that may occur between the close of the foreign exchanges and the time for valuation. These models take into account available market data including intraday index, ADR, and ETF movements.

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

The Fund does not hold any significant investments (greater than one percent of net assets) categorized as Level 3.

Financial assets were transferred from Level 2 to Level 3 as trading halted during the period. As a result, as of period end, the Committee determined to value the security(s) under consistently applied procedures established by and under the general supervision of the Board.

The following table shows transfers between Level 2 and Level 3 of the fair value hierarchy:

Transfers In				Transfers Out
Level 2		Level 3		Level 2		Level 3
$	-	$	55,274,689	$	55,274,689	$	-

Transfers in and/or out of Level 3 are determined based on the fair value at the beginning of the period for security positions held throughout the period.

Certain securities classified as Level 3 are valued by the Committee at fair value, using a market approach, as determined in good faith under consistently applied procedures established by and under the general supervision of the Board. To determine fair value for these securities, for which no market exists, the Committee utilizes the valuation technique it deems most appropriate in the circumstances, using some unobservable inputs, which may include, but are not limited to estimated earnings of the company and the position of the security within the company's capital structure. The Committee also may use some observable inputs, which may include, but are not limited to, trades of similar securities. Significant increases or decreases to any of these inputs could result in a significantly lower or higher fair value measurement.

See accompanying notes to financial statements.

COLUMBIA ACORN INTERNATIONAL®

PORTFOLIO DIVERSIFICATION (UNAUDITED)

At June 30, 2015, the Fund's portfolio investments as a percentage of net assets were diversified as follows:

	Value		Percentage of Net Assets
> Industrial Goods & Services
Machinery	$	495,014,931		6.2
Industrial Materials & Specialty Chemicals		457,184,821		5.8
Other Industrial Services		402,120,164		5.1
Electrical Components		226,939,703		2.9
Conglomerates		210,820,970		2.7
Outsourcing Services		199,092,875		2.5
Construction		70,535,524		0.9
Waste Management		53,103,100		0.7
Water		44,640,927		0.5
Industrial Distribution		15,478,331		0.2
		2,174,931,346		27.5
> Consumer Goods & Services
Retail		609,456,518		7.7
Food & Beverage		273,424,269		3.5
Casinos & Gaming		187,863,479		2.4
Nondurables		142,865,342		1.8
Consumer Goods Distribution		110,950,873		1.4
Other Durable Goods		94,460,809		1.2
Travel		92,030,814		1.2
Restaurants		90,795,220		1.1
Furniture & Textiles		54,215,140		0.7
Leisure Products		41,430,891		0.5
Apparel		30,365,821		0.4
Consumer Electronics		29,588,201		0.4
Educational Services		24,748,518		0.3
Other Consumer Services		15,025,487		0.2
		1,797,221,382		22.8
> Information
Business Software		270,139,222		3.4
Computer Hardware & Related Equipment		133,865,659		1.7
Mobile Communications		127,138,632		1.6
Semiconductors & Related Equipment		119,341,741		1.5
Financial Processors		115,598,998		1.5
Internet Related		115,283,213		1.4
Entertainment Programming		77,791,018		1.0
Satellite Broadcasting & Services		68,084,046		0.9
Instrumentation		65,266,878		0.8
Advertising		55,744,752		0.7
Computer Services		53,301,671		0.7
Cable TV		52,402,255		0.7
Telephone & Data Services		47,090,360		0.6
Telecommunications Equipment		45,546,177		0.6
TV Broadcasting		43,835,330		0.5
Business Information & Marketing Services		30,613,337		0.4
		1,421,043,289		18.0

	Value			Percentage of Net Assets
> Finance
Banks	$	254,382,516			3.2
Insurance		219,557,185			2.8
Brokerage & Money Management		156,514,943			2.0
Finance Companies		38,572,230			0.5
Financial Processors		21,639,007			0.2
		690,665,881			8.7
> Other Industries
Real Estate		393,040,028			5.0
Transportation		181,625,633			2.3
Regulated Utilities		35,485,633			0.4
		610,151,294			7.7
> Health Care
Pharmaceuticals		183,360,658			2.3
Medical Equipment & Devices		105,137,062			1.3
Medical Supplies		93,411,326			1.2
Health Care Services		44,210,736			0.6
Hospital Management		22,795,729			0.3
		448,915,511			5.7
> Energy & Minerals
Oil & Gas Producers		140,816,282			1.8
Oil Refining, Marketing & Distribution		82,866,131			1.0
Mining		61,437,909			0.8
Oil Services		44,305,901			0.6
Non-Ferrous Metals		24,570,606			0.3
Agricultural Commodities		12,336,362			0.1
		366,333,191			4.6
Total Equities:		7,509,261,894			95.0
Short-Term Investments:		334,794,388			4.2
Securities Lending Collateral:		186,393,214			2.4
Total Investments:		8,030,449,496			101.6
Obligation to Return Collateral for Securities Loaned:		(186,393,214	)		(2.4	)
Cash and Other Assets Less Liabilities:		58,285,708			0.8
Net Assets:	$	7,902,341,990			100.0

See accompanying notes to financial statements.

COLUMBIA ACORN USA®

MAJOR PORTFOLIO CHANGES IN THE SECOND QUARTER (UNAUDITED)

	Number of Shares
	3/31/15		6/30/15
Purchases
Information
Audience		0		722,320
Bankrate		218,000		719,487
DemandWare		145,000		197,360
Liquidity Services		153,000		294,000
Lumos Networks		0		304,372
Navigant Consulting		0		366,739
Sanmina		0		350,804
Textura		373,934		482,473
Industrial Goods & Services
Donaldson		855,000		948,000
Dorman Products		149,293		182,079
Generac		276,000		299,171
Lumber Liquidators		0		96,000
Oshkosh Corporation		0		166,548
Consumer Goods & Services
Arctic Cat		0		111,261
Blue Nile		0		87,000
Casey's General Stores		73,931		86,242
Fiesta Restaurant Group		68,000		130,773
Fossil		0		33,310
Gaiam		0		193,577
Gentex		296,000		399,477
Hertz		345,000		506,306
Knoll		357,000		383,060
Papa John's International		79,000		138,235
Select Comfort		297,000		377,438
The Fresh Market		234,000		494,833
Zulily		0		252,955
Finance
Hancock Holding		228,000		268,466
Lakeland Financial		392,597		421,366
LegacyTexas		373,487		422,366
Leucadia National		0		243,993
SEI Investments		139,000		343,089
Health Care
Agios Pharmaceuticals		26,000		46,972
Allscripts Healthcare Solutions		343,600		506,139
Sarepta Therapeutics		338,500		429,694
Sirona Dental Systems		0		63,289
Ultragenyx Pharmaceutical		154,000		193,081
VWR		86,300		229,638
Wright Medical Group		200,300		258,854
Energy & Minerals
Core Labs (Netherlands)		39,000		49,965
Gulfport Energy		51,000		93,267

	Number of Shares
	3/31/15		6/30/15
Sales
Information
Atmel		970,000		249,822
Envestnet		82,000		0
Fleetmatics		97,000		0
inContact		394,187		315,276
Informatica		214,000		0
Mettler-Toledo International		141,000		117,400
RPX		211,000		0
Rubicon Technology		600,000		499,644
SBA Communications		23,000		0
Trimble Navigation		274,000		0
Industrial Goods & Services
Acuity Brands		64,000		0
Drew Industries		539,000		389,722
Kennametal		239,000		143,520
Consumer Goods & Services
Burlington Stores		207,500		0
Caesarstone (Israel)		189,814		150,828
Choice Hotels		89,666		71,306
Michaels Stores		203,784		0
Shutterfly		147,845		0
The Chefs' Warehouse		268,276		129,908
United Natural Foods		134,000		101,595
Finance
First Busey		1,484,641		1,109,542
Marlin Business Services		418,543		334,361
MB Financial		733,000		529,623
Patriot National		515,590		497,176
World Acceptance		135,125		108,257
Heath Care
Akorn		442,117		358,549
Alnylam Pharmaceuticals		40,100		0
Bio-Techne		135,200		114,086
Celldex Therapeutics		280,300		260,148
Seattle Genetics		286,800		183,203
Synageva BioPharma		271,469		0
Other Industries
EdR		328,933		228,671
Extra Space Storage		611,000		587,914
Post Properties		91,000		0
Energy & Minerals
Rosetta Resources		159,000		0

See accompanying notes to financial statements.

COLUMBIA ACORN USA®

STATEMENT OF INVESTMENTS (UNAUDITED), JUNE 30, 2015

Number of Shares			Value
			Equities: 93.9%
Information 23.4%
		> Business Software 7.1%
	230,000	Ansys (a)	$	20,985,200
		Simulation Software for Engineers & Designers
	245,682	SPS Commerce		16,165,876
		Supply Chain Management Software Delivered via the Web
	197,360	DemandWare (a)		14,028,349
		E-Commerce Website Platform for Retailers & Apparel Manufacturers
	482,473	Textura (b)		13,427,223
		Construction Vendor Management Software
	111,053	NetSuite		10,189,113
		Enterprise Software Delivered via the Web
	196,527	Solera Holdings		8,757,243
		Software for Automotive Insurance Claims Processing
	816,768	Amber Road (a)		5,733,711
		Global Trade Management Software Delivered via the Web
	315,276	inContact		3,111,774
		Call Center Systems Delivered via the Web & Telco Services
	30,092	Cvent (a)		775,772
		Software for Corporate Event Planners & Marketing Platform for Hotels
				93,174,261
		> Instrumentation 5.6%
	117,400	Mettler-Toledo International		40,087,404
		Laboratory Equipment
	383,000	IPG Photonics		32,622,025
		Fiber Lasers
				72,709,429
		> Computer Services 3.5%
	554,605	ExlService Holdings (a)		19,178,241
		Business Process Outsourcing
	231,502	Virtusa		11,899,203
		Offshore IT Outsourcing
	291,459	WNS - ADR		7,796,528
		Offshore Business Process Outsourcing Services
	432,000	Hackett Group		5,801,760
		IT Integration & Best Practice Research
	302,000	RCM Technologies		1,709,320
		Technology & Engineering Services
				46,385,052
		> Computer Hardware & Related Equipment 1.0%
	113,253	Rogers		7,490,553
		Printed Circuit Materials & High Performance Foams
	73,282	Belden		5,952,697
		Specialty Cable
				13,443,250

Number of Shares			Value
		> Business Information & Marketing Services 1.0%
	719,487	Bankrate (a)	$	7,547,418
		Internet Advertising for the Insurance, Credit Card & Banking Markets
	366,739	Navigant Consulting		5,453,409
		Financial Consulting Firm
				13,000,827
		> Mobile Communications 0.9%
	401,486	Gogo (b)		8,603,845
		Provider of Wi-Fi on Airplanes
	722,320	Audience (a)(b)		3,532,145
		Improving Voice Quality for Mobile Devices
				12,135,990
		> Financial Processors 0.8%
	77,000	Global Payments		7,965,650
		Credit Card Processor
	294,000	Liquidity Services		2,831,220
		E-Auctions for Surplus & Salvage Goods
				10,796,870
		> Semiconductors & Related Equipment 0.8%
	138,235	Monolithic Power Systems		7,009,897
		High Performance Analog & Mixed Signal Integrated Circuits
	249,822	Atmel		2,461,996
		Microcontrollers, Radio Frequency & Memory Semiconductors
	499,644	Rubicon Technology (b)		1,214,135
		Producer of Sapphire for the Lighting, Electronics & Automotive Industries
				10,686,028
		> Telephone & Data Services 0.7%
	621,000	Boingo Wireless (a)		5,129,460
		Wi-Fi & Cellular Communications Networks
	304,372	Lumos Networks		4,501,662
		Telephone & Fiber Optic Data Services
				9,631,122
		> Telecommunications Equipment 0.7%
	444,683	Infinera		9,329,449
		Optical Networking Equipment
		> Internet Related 0.7%
	249,567	RetailMeNot		4,449,780
		Digital Coupon Marketplace
	826,078	Vonage		4,056,043
		Business & Consumer Internet Telephony
				8,505,823
		> Contract Manufacturing 0.6%
	350,804	Sanmina		7,072,209
		Electronic Manufacturing Services
Information: Total				306,870,310

See accompanying notes to financial statements.

COLUMBIA ACORN USA®

STATEMENT OF INVESTMENTS (UNAUDITED), CONTINUED

Number of Shares			Value
Industrial Goods & Services 21.5%
		> Machinery 18.3%
	793,000	Ametek	$	43,440,540
		Aerospace/Industrial Instruments
	515,000	Nordson		40,113,350
		Dispensing Systems for Adhesives & Coatings
	725,500	HEICO		36,833,635
		FAA-approved Aircraft Replacement Parts
	948,000	Donaldson		33,938,400
		Industrial Air Filtration
	238,000	Moog		16,821,840
		Motion Control Products for Aerospace, Defense & Industrial Markets
	222,000	Toro		15,047,160
		Turf Maintenance Equipment
	299,171	Generac (a)(b)		11,892,047
		Standby Power Generators
	278,135	ESCO Technologies		10,405,030
		Industrial Filtration & Advanced Measurement Equipment
	79,943	Middleby		8,972,003
		Manufacturer of Cooking Equipment
	182,079	Dorman Products (a)(b)		8,677,885
		Aftermarket Auto Parts Distributor
	166,548	Oshkosh		7,058,304
		Specialty Truck Manufacturer
	143,520	Kennametal		4,896,903
		Consumable Cutting Tools
	76,612	Graham		1,569,780
		Designer & Builder of Vacuum & Heat Transfer Equipment for Process Industries
				239,666,877
		> Industrial Materials & Specialty Chemicals 1.7%
	389,722	Drew Industries		22,611,671
		RV & Manufactured Home Components
		> Construction 0.6%
	389,722	PGT		5,654,866
		Wind Resistant Windows & Doors
	96,000	Lumber Liquidators (b)		1,988,160
		Hardwood Flooring Retailer
				7,643,026
		> Industrial Distribution 0.5%
	90,000	WESCO International		6,177,600
		Industrial Distributor
		> Electrical Components 0.4%
	235,103	Thermon		5,658,929
		Global Engineered Thermal Solutions
Industrial Goods & Services: Total				281,758,103
Consumer Goods & Services 14.8%
		> Travel 3.3%
	425,950	Avis Budget Group (a)		18,775,876
		Car Rental Company
	506,306	Hertz		9,174,265
		U.S. Rental Car Operator

Number of Shares			Value
	246,491	HomeAway	$	7,670,800
		Vacation Rental Online Marketplace
	71,306	Choice Hotels		3,868,350
		Franchisor of Budget Hotel Brands
	28,314	Vail Resorts		3,091,889
		Ski Resort Operator & Developer
				42,581,180
		> Retail 2.6%
	494,833	The Fresh Market (a)(b)		15,903,933
		Specialty Food Retailer
	86,242	Casey's General Stores		8,256,809
		Owner/Operator of Convenience Stores
	252,955	Zulily (b)		3,298,533
		E-Commerce Retailer Offering Flash Sale Events
	87,000	Blue Nile (a)		2,643,930
		Online Jewelry Retailer
	33,310	Fossil (a)		2,310,382
		Watch Designer & Retailer
	193,577	Gaiam (a)		1,265,993
		Promoter of Healthy Living through Catalogs, E-Commerce & Gaiam TV
				33,679,580
		> Other Durable Goods 2.4%
	187,000	Cavco Industries (a)		14,107,280
		Manufactured Homes
	377,438	Select Comfort		11,349,561
		Specialty Mattresses
	399,477	Gentex		6,559,412
		Manufacturer of Auto Parts
				32,016,253
		> Consumer Goods Distribution 2.0%
	249,822	Pool		17,532,508
		Swimming Pool Supplies & Equipment Distributor
	101,595	United Natural Foods		6,469,569
		Distributor of Natural/Organic Foods to Grocery Stores
	129,908	The Chefs' Warehouse (a)(b)		2,759,246
		Distributor of Specialty Foods to Fine Dining Restaurants
				26,761,323
		> Furniture & Textiles 1.5%
	150,828	Caesarstone (Israel)		10,337,751
		Quartz Countertops
	383,060	Knoll		9,587,992
		Office Furniture
				19,925,743
		> Restaurants 1.3%
	138,235	Papa John's International		10,451,948
		Franchisor of Pizza Restaurants
	130,773	Fiesta Restaurant Group (a)		6,538,650
		Owner/Operator of Two Restaurant Chains: Pollo Tropical & Taco Cabana
				16,990,598
		> Other Consumer Services 0.9%
	298,954	Blackhawk Network (a)		12,316,905
		Third-party Distributor of Prepaid Content, Mostly Gift Cards

See accompanying notes to financial statements.

Number of Shares			Value
		> Leisure Products 0.8%
	363,764	Performance Sports Group	$	6,547,752
		Sporting Goods Manufacturer
	111,261	Arctic Cat		3,694,978
		Manufacturer of ATVs & Snowmobiles
				10,242,730
Consumer Goods & Services: Total				194,514,312
Finance 13.9%
		> Banks 8.0%
	131,573	SVB Financial Group		18,943,881
		Bank to Venture Capitalists
	421,366	Lakeland Financial		18,274,643
		Indiana Bank
	529,623	MB Financial		18,240,216
		Chicago Bank
	881,038	Associated Banc-Corp		17,858,640
		Midwest Bank
	268,466	Hancock Holding		8,566,750
		Gulf Coast Bank
	1,109,542	First Busey		7,289,691
		Illinois Bank
	695,000	TrustCo Bank		4,885,850
		New York State Bank
	162,981	Sandy Spring Bancorp		4,560,208
		Baltimore & Washington, D.C. Bank
	311,445	First Commonwealth		2,986,758
		Western Pennsylvania Bank
	168,031	Guaranty Bancorp		2,774,192
		Colorado Bank
				104,380,829
		> Finance Companies 2.2%
	490,177	CAI International (a)		10,092,744
		International Container Leasing
	108,257	World Acceptance (b)		6,658,888
		Personal Loans
	214,681	McGrath Rentcorp		6,532,743
		Mini-rental Conglomerate
	334,361	Marlin Business Services		5,644,014
		Small Equipment Leasing
				28,928,389
		> Brokerage & Money Management 1.3%
	343,089	SEI Investments		16,821,654
		Mutual Fund Administration & Investment Management
		> Insurance 1.0%
	497,176	Patriot National		7,954,816
		Underwriting, Claims Administration & Case Management Outsourcing for Workers Comp Insurers
	134,904	Allied World Assurance Company Holdings		5,830,551
		Commercial Lines Insurance/Reinsurance
				13,785,367
		> Savings & Loans 1.0%
	422,366	LegacyTexas		12,755,453
		Texas Thrift

Number of Shares			Value
		> Diversified Financial Companies 0.4%
	243,993	Leucadia National	$	5,924,150
		Holding Company
Finance: Total				182,595,842
Health Care 12.5%
		> Biotechnology & Drug Delivery 4.4%
	193,081	Ultragenyx Pharmaceutical		19,769,564
		Biotech Focused on "Ultra-Orphan" Drugs
	429,694	Sarepta Therapeutics (b)		13,075,588
		Biotech Focused on Rare Diseases
	183,203	Seattle Genetics (b)		8,867,025
		Antibody-based Therapies for Cancer
	260,148	Celldex Therapeutics (a)		6,560,933
		Biotech Developing Drugs for Cancer
	46,972	Agios Pharmaceuticals (a)(b)		5,220,468
		Biotech Focused on Cancer & Orphan Diseases
	16,655	Intercept Pharmaceuticals		4,020,184
		Biotech Developing Drugs for Several Diseases
				57,513,762
		> Medical Supplies 3.4%
	449,680	Cepheid (a)		27,497,932
		Molecular Diagnostics
	114,086	Bio-Techne		11,234,048
		Maker of Consumables & Systems for the Life Science Market
	229,638	VWR		6,138,224
		Distributor of Lab Supplies
				44,870,204
		> Health Care Services 2.2%
	183,886	Medidata Solutions		9,988,687
		Cloud-based Software for Drug Studies
	506,139	Allscripts Healthcare Solutions (a)		6,923,982
		Health Care IT
	144,897	HealthSouth		6,673,956
		Inpatient Rehabilitation Facilities & Home Health Care
	116,584	Envision Healthcare Holdings (a)		4,602,736
		Provider of Health Care Outsourcing Services
				28,189,361
		> Medical Equipment & Devices 1.3%
	258,854	Wright Medical Group		6,797,506
		Foot & Ankle Replacement
	63,289	Sirona Dental Systems		6,355,482
		Manufacturer of Dental Equipment
	77,961	Abaxis		4,013,432
		Instruments & Tests for Vet & Medical Markets
				17,166,420
		> Pharmaceuticals 1.2%
	358,549	Akorn (a)		15,654,249
		Developer, Manufacturer & Distributor of Specialty Generic Drugs
Health Care: Total				163,393,996

See accompanying notes to financial statements.

COLUMBIA ACORN USA®

STATEMENT OF INVESTMENTS (UNAUDITED), CONTINUED

Number of Shares			Value
Other Industries 5.3%
		> Real Estate 3.5%
	587,914	Extra Space Storage	$	38,343,751
		Self Storage Facilities
	228,671	EdR		7,171,123
		Student Housing
				45,514,874
		> Transportation 1.8%
	468,091	Rush Enterprises, Class A		12,268,665
	105,000	Rush Enterprises, Class B		2,520,000
		Truck Sales & Service
	416,370	Heartland Express		8,423,165
		Regional Trucker
				23,211,830
Other Industries: Total				68,726,704
Energy & Minerals 2.5%
		> Oil & Gas Producers 1.6%
	138,235	Carrizo Oil & Gas (a)		6,806,691
		Oil & Gas Producer
	97,943	PDC Energy		5,253,663
		Oil & Gas Producer in the United States
	66,620	Clayton Williams (b)		4,380,265
		Oil & Gas Producer
	101,595	SM Energy		4,685,561
		Oil & Gas Producer
				21,126,180
		> Oil Services 0.5%
	93,267	Gulfport Energy		3,753,997
		Oil & Gas Producer Focused on Utica Shale in Ohio
	133,239	Hornbeck Offshore		2,735,396
		Supply Vessel Operator in Gulf of Mexico
				6,489,393

Number of Shares			Value
		> Mining 0.4%
	49,965	Core Labs (Netherlands) (b)	$	5,698,009
		Oil & Gas Reservoir Consulting
Energy & Minerals: Total				33,313,582
Total Equities: 93.9% (Cost: $697,779,609)				1,231,172,849	(c)
Short-Term Investments 6.3%
	82,842,913	JPMorgan U.S. Government Money Market Fund, Agency Shares (7 day yield of 0.01%)		82,842,913
Total Short-Term Investments: 6.3% (Cost: $82,842,913)				82,842,913
Securities Lending Collateral 4.1%
	53,302,525	Dreyfus Government Cash Management Fund, Institutional Shares (7 day yield of 0.01%) (d)		53,302,525
Total Securities Lending Collateral: 4.1% (Cost: $53,302,525)				53,302,525
Total Investments: 104.3% (Cost: $833,925,047)(e)				1,367,318,287
Obligation to Return Collateral for Securities Loaned: (4.1)%				(53,302,525	)
Cash and Other Assets Less Liabilities: (0.2)%				(2,439,622	)
Net Assets: 100.0%			$	1,311,576,140

ADR - American Depositary Receipts

See accompanying notes to financial statements.

> Notes to Statement of Investments

(a) Non-income producing security.

(b) All or a portion of this security was on loan at June 30, 2015. The total market value of securities on loan at June 30, 2015 was $53,095,035.

(c) On June 30, 2015, the market value of foreign securities represented 1.22% of total net assets. The Fund's foreign portfolio was diversified as follows:

Country	Value		Percentage of Net Assets
Israel	$	10,337,751		0.79
Netherlands		5,698,009		0.43
Total Foreign Portfolio	$	16,035,760		1.22

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

(e) At June 30, 2015, for federal income tax purposes, the cost of investments was approximately $833,925,047 and net unrealized appreciation was $533,393,240 consisting of gross unrealized appreciation of $562,908,526 and gross unrealized depreciation of $29,515,286.

> Notes to Statement of Investments

Fair Value Measurements

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

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

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

The Committee is responsible for applying the Trust's Portfolio Pricing Policy and the CWAM pricing procedures (the Policies), which are approved by and subject to the oversight of the Board.

The following table summarizes the inputs used, as of June 30, 2015, in valuing the Fund's assets:

Investment Type	Quoted Prices (Level 1)		Other Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Equities
Information	$	306,870,310	$	-	$	-	$	306,870,310
Industrial Goods & Services		281,758,103		-		-		281,758,103
Consumer Goods & Services		194,514,312		-		-		194,514,312
Finance		182,595,842		-		-		182,595,842
Health Care		163,393,996		-		-		163,393,996
Other Industries		68,726,704		-		-		68,726,704
Energy & Minerals		33,313,582		-		-		33,313,582
Total Equities		1,231,172,849		-		-		1,231,172,849
Total Short-Term Investments		82,842,913		-		-		82,842,913
Total Securities Lending Collateral		53,302,525		-		-		53,302,525
Total Investments	$	1,367,318,287	$	-	$	-	$	1,367,318,287

There were no transfers of financial assets between levels during the period.

See accompanying notes to financial statements.

COLUMBIA ACORN INTERNATIONAL SELECT^SM

MAJOR PORTFOLIO CHANGES IN THE SECOND QUARTER (UNAUDITED)

	Number of Shares
	3/31/15		6/30/15
Purchases
Asia
> Hong Kong
Hong Kong Exchanges and Clearing		0		121,517
> Taiwan
Largan Precision		0		22,000
Europe
> United Kingdom
WH Smith		126,000		232,000
> Germany
MTU Aero Engines		56,000		62,300
> France
Vivendi		0		111,000
> Denmark
Novozymes		65,500		71,500
Other Countries
> Canada
Vermilion Energy		56,000		85,000
> South Africa
Naspers		33,000		61,000
> United States
Anadarko Petroleum		0		27,000

	Number of Shares
	3/31/15		6/30/15
Sales
Asia
> Japan
Japan Tobacco		190,000		160,000
KDDI		399,000		359,000
NGK Spark Plug		206,300		190,600
Park24		181,000		128,000
Recruit Holdings		297,400		262,000
Secom		132,000		120,000
Seven Bank		777,000		0
> Korea
CJ Corp		37,194		26,294
> Singapore
Ascendas REIT		2,650,000		0
CapitaLand Mall Trust		6,491,000		5,824,000
Singapore Exchange		2,036,000		1,564,000
Europe
> United Kingdom
Babcock International		330,000		162,000
Whitbread		47,689		32,000
> Germany
Telefonica Deutschland		1,305,500		976,500
> Spain
Viscofan		44,000		39,000
> Norway
Orkla		511,000		453,000
Other Countries
> Canada
CCL Industries		67,000		51,000
> Australia
Amcor		350,000		320,000
Challenger Financial		2,062,000		670,000

See accompanying notes to financial statements.

COLUMBIA ACORN INTERNATIONAL SELECT^SM

STATEMENT OF INVESTMENTS (UNAUDITED), JUNE 30, 2015

Number of Shares			Value
			Equities: 97.0%
Asia 42.6%
		> Japan 23.0%
	359,000	KDDI	$	8,663,371
		Mobile & Fixed Line Communication Service Provider in Japan
	262,000	Recruit Holdings		7,989,497
		Recruitment & Media Services
	120,000	Secom		7,795,868
		Security Services
	160,000	Japan Tobacco		5,687,885
		Cigarettes
	190,600	NGK Spark Plug		5,278,511
		Automobile Parts
	2,400	Orix JREIT		3,456,764
		Diversified REIT
	1,530	Nippon Prologis REIT		2,815,417
		Logistics REIT in Japan
	1,300	Japan Retail Fund		2,599,596
		Retail REIT in Japan
	133,000	Aeon Mall		2,490,528
		Suburban Shopping Mall Developer, Owner & Operator
	30,700	Rinnai		2,417,475
		Gas Appliances for Home & Commercial Use
	128,000	Park24		2,191,293
		Parking Lot Operator
				51,386,205
		> Korea 8.4%
	26,294	CJ Corp		6,966,175
		Holding Company of Korean Consumer Conglomerate
	23,200	Samsung Fire and Marine		6,113,229
		Non-life Insurance
	66,800	KT&G		5,683,195
		Tobacco & Ginseng Products
				18,762,599
		> Singapore 8.2%
	5,824,000	CapitaLand Mall Trust		9,289,774
		Singapore Commercial Property Real Estate Investment Trust
	1,564,000	Singapore Exchange		9,085,509
		Singapore Equity & Derivatives Market Operator
				18,375,283
		> Hong Kong 1.9%
	121,517	Hong Kong Exchanges and Clearing		4,281,599
		Hong Kong Equity & Derivatives Market Operator
		> Taiwan 1.1%
	22,000	Largan Precision		2,511,318
		Mobile Device Camera Lenses & Modules
Asia: Total				95,317,004

Number of Shares			Value
Europe 32.0%
		> United Kingdom 7.9%
	232,000	WH Smith	$	5,570,018
		Newsprint, Books & General Stationery Retailer
	162,000	Babcock International		2,749,059
		Public Sector Outsourcer
	32,000	Whitbread		2,486,849
		UK Hotelier & Coffee Shop
	147,000	Jardine Lloyd Thompson Group		2,411,366
		International Business Insurance Broker
	100,000	Aggreko		2,261,028
		Temporary Power & Temperature Control Services
	130,000	Smith & Nephew		2,193,779
		Medical Equipment & Supplies
				17,672,099
		> Germany 7.0%
	62,300	MTU Aero Engines		5,859,929
		Airplane Engine Components & Services
	976,500	Telefonica Deutschland		5,628,324
		Mobile & Fixed-line Communications in Germany
	107,400	Wirecard (a)		4,112,892
		Online Payment Processing & Risk Management
				15,601,145
		> Switzerland 3.8%
	21,040	Partners Group		6,289,834
		Private Markets Asset Management
	6,600	Geberit		2,200,353
		Plumbing Systems
				8,490,187
		> France 3.4%
	146,000	Eutelsat		4,712,135
		Fixed Satellite Services
	111,000	Vivendi (a)		2,799,805
		Global Media Conglomerate
				7,511,940
		> Spain 3.3%
	655,000	Distribuidora Internacional de Alimentación		5,002,051
		Discount Retailer in Spain & Latin America
	39,000	Viscofan		2,358,743
		Sausage Casings Maker
				7,360,794
		> Sweden 2.5%
	120,000	Swedish Match		3,413,331
		Swedish Snus
	62,900	Hexagon		2,279,313
		Design, Measurement & Visualization Software & Equipment
				5,692,644
		> Norway 1.6%
	453,000	Orkla		3,564,859
		Food & Brands, Aluminum, Chemicals Conglomerate

See accompanying notes to financial statements.

COLUMBIA ACORN INTERNATIONAL SELECT^SM

STATEMENT OF INVESTMENTS (UNAUDITED), CONTINUED

Number of Shares			Value
		> Denmark 1.5%
	71,500	Novozymes	$	3,398,758
		Industrial Enzymes
		> Netherlands 1.0%
	44,000	Vopak		2,220,401
		Operator of Petroleum & Chemical Storage Terminals
Europe: Total				71,512,827
Other Countries 17.6%
		> Canada 6.3%
	51,000	CCL Industries		6,255,565
		Global Label Converter
	258,000	Goldcorp		4,179,600
		Gold Mining
	85,000	Vermilion Energy (a)		3,671,537
		Canadian Exploration & Production Company
				14,106,702
		> South Africa 6.3%
	61,000	Naspers		9,501,479
		Media in Africa, China, Russia & other Emerging Markets
	663,000	Coronation Fund Managers		4,491,027
		South African Fund Manager
				13,992,506
		> Australia 4.1%
	670,000	Challenger Financial		3,473,008
		Annuity Provider in Australia
	320,000	Amcor		3,381,601
		Global Leader in Flexible & Rigid Packaging
	514,000	IAG		2,209,879
		General Insurance Provider
				9,064,488
		> United States 0.9%
	27,000	Anadarko Petroleum		2,107,620
		Worldwide Production of Oil & Gas
Other Countries: Total				39,271,316
Latin America 4.8%
		> Guatemala 3.2%
	588,000	Tahoe Resources		7,127,558
		Silver & Gold Projects in Guatemala & Peru

Number of Shares			Value
		> Uruguay 0.8%
	191,666	Union Agriculture Group (b)(c)(d)	$	1,809,327
		Farmland Operator in Uruguay
		> Brazil 0.8%
	12,057,582	Beadell Resources		1,735,415
		Gold Mining in Brazil
Latin America: Total				10,672,300
Total Equities: 97.0% (Cost: $194,334,492)				216,773,447	(e)
Short-Term Investments 3.1%
	7,097,178	JPMorgan U.S. Government Money Market Fund, IM Shares (7 day yield of 0.01%)		7,097,178
Total Short-Term Investments: 3.1% (Cost: $7,097,178)				7,097,178
Securities Lending Collateral 3.8%
	8,381,123	Dreyfus Government Cash Management Fund, Institutional Shares (7 day yield of 0.01%) (f)		8,381,123
Total Securities Lending Collateral: 3.8% (Cost: $8,381,123)				8,381,123
Total Investments: 103.9% (Cost: $209,812,793)(g)				232,251,748
Obligation to Return Collateral for Securities Loaned: (3.8)%				(8,381,123	)
Cash and Other Assets Less Liabilities: (0.1)%				(439,042	)
Net Assets: 100.0%			$	223,431,583

REIT - Real Estate Investment Trust

> Notes to Statement of Investments

(a) All or a portion of this security was on loan at June 30, 2015. The total market value of securities on loan at June 30, 2015 was $7,925,539.

(b) Non-income producing security.

(c) Denotes a restricted security, which is subject to restrictions on resale under federal securities laws. This security is valued at fair value determined in good faith under consistently applied procedures established by the Fund's Board of Trustees. At June 30, 2015, the market value of this security amounted to $1,809,327, which represented 0.81% of total net assets. Additional information on this security is as follows:

Security				Acquisition Dates				Shares/Units				Cost				Value
Union Agriculture Group				12/8/10-6/27/12					191,666			$	2,200,000			$	1,809,327

(d) Illiquid security.

See accompanying notes to financial statements.

> Notes to Statement of Investments

(e) On June 30, 2015, the Fund's total equity investments were denominated in currencies as follows:

Currency	Value		Percentage of Net Assets
Japanese Yen	$	51,386,205		23.0
Euro		32,694,280		14.6
South Korean Won		18,762,599		8.4
Singapore Dollar		18,375,283		8.2
British Pound		17,672,099		7.9
Canadian Dollar		17,054,660		7.6
South African Rand		13,992,506		6.3
Other currencies less than 5% of total net assets		46,835,815		21.0
Total Equities	$	216,773,447		97.0

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

(g) At June 30, 2015, for federal income tax purposes, the cost of investments was approximately $209,812,793 and net unrealized appreciation was $22,438,955 consisting of gross unrealized appreciation of $39,310,920 and gross unrealized depreciation of $16,871,965.

At June 30, 2015, the Fund had entered into the following forward foreign currency exchange contracts:

Forward Foreign Currency Exchange Contracts to Buy				Forward Foreign Currency Exchange Contracts to Sell				Principal Amount in Foreign Currency				Principal Amount in U.S. Dollar				Settlement Date				Unrealized Appreciation (Depreciation)
USD				ZAR					112,653,000			$	9,000,000			7/15/15				$	(237,682	)

The counterparty for all forward foreign currency exchange contracts is Morgan Stanley.

USD - U.S. Dollar

ZAR - South African Rand

Fair Value Measurements

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

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

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

The Committee is responsible for applying the Trust's Portfolio Pricing Policy and the CWAM pricing procedures (the Policies), which are approved by and subject to the oversight of the Board.

See accompanying notes to financial statements.

COLUMBIA ACORN INTERNATIONAL SELECT^SM

STATEMENT OF INVESTMENTS (UNAUDITED), CONTINUED

> Notes to Statement of Investments

those securities and changes in fair value. Significant changes in any of these factors could result in lower or higher fair value measurements. Various factors impact the frequency of monitoring (which may occur as often as daily), however the Committee may determine that changes to inputs, assumptions and models are not required with the same frequency.

The following table summarizes the inputs used, as of June 30, 2015, in valuing the Fund's assets:

Investment Type	Quoted Prices (Level 1)		Other Significant Observable Inputs (Level 2)			Significant Unobservable Inputs (Level 3)		Total
Equities
Asia	$	–	$	95,317,004		$	–	$	95,317,004
Europe		–		71,512,827			–		71,512,827
Other Countries		16,214,322		23,056,994			–		39,271,316
Latin America		7,127,558		1,735,415			1,809,327		10,672,300
Total Equities		23,341,880		191,622,240			1,809,327		216,773,447
Total Short-Term Investments		7,097,178		–			–		7,097,178
Total Securities Lending Collateral		8,381,123		–			–		8,381,123
Total Investments	$	38,820,181	$	191,622,240		$	1,809,327	$	232,251,748
Derivatives
Liabilities
Forward Foreign Currency Exchange Contracts		–		(237,682	)		–		(237,682	)
Total	$	38,820,181	$	191,384,558		$	1,809,327	$	232,014,066

There were no transfers of financial assets between levels during the period.

The Fund does not hold any significant investments (greater than one percent of net assets) categorized as Level 3.

See accompanying notes to financial statements.

COLUMBIA ACORN INTERNATIONAL SELECT^SM

PORTFOLIO DIVERSIFICATION (UNAUDITED)

At June 30, 2015, the Fund's portfolio investments as a percentage of net assets were diversified as follows:

	Value		Percentage of Net Assets
> Information
Financial Processors	$	17,480,000		7.8
Internet Related		9,501,479		4.3
Mobile Communications		8,663,371		3.9
Advertising		7,989,497		3.6
Telephone & Data Services		5,628,324		2.5
Satellite Broadcasting & Services		4,712,135		2.1
Telecommunications Equipment		2,511,318		1.1
Business Software		2,279,313		1.0
		58,765,437		26.3
> Consumer Goods & Services
Nondurables		17,626,644		7.9
Retail		10,572,069		4.7
Other Durable Goods		7,695,987		3.4
Food & Beverage		5,772,074		2.6
Other Consumer Services		2,799,805		1.3
Restaurants		2,486,849		1.1
		46,953,428		21.0
> Industrial Goods & Services
Other Industrial Services		18,108,119		8.1
Conglomerates		10,531,034		4.7
Industrial Materials & Specialty Chemicals		6,780,359		3.1
Outsourcing Services		2,749,059		1.2
Construction		2,200,353		1.0
		40,368,924		18.1
> Finance
Insurance		14,207,481		6.4
Brokerage & Money Management		10,780,861		4.8
		24,988,342		11.2
> Energy & Minerals
Mining		13,042,573		5.8
Oil & Gas Producers		5,779,157		2.6
Oil Refining, Marketing & Distribution		2,220,402		1.0
Agricultural Commodities		1,809,327		0.8
		22,851,459		10.2
> Other Industries
Real Estate		20,652,078		9.2
		20,652,078		9.2

	Value			Percentage of Net Assets
> Health Care
Medical Equipment & Devices	$	2,193,779			1.0
		2,193,779			1.0
Total Equities:		216,773,447			97.0
Short-Term Investments:		7,097,178			3.1
Securities Lending Collateral:		8,381,123			3.8
Total Investments:		232,251,748			103.9
Obligation to Return Collateral for Securities Loaned:		(8,381,123	)		(3.8	)
Cash and Other Assets Less Liabilities:		(439,042	)		(0.1	)
Net Assets:	$	223,431,583			100.0

See accompanying notes to financial statements.

COLUMBIA ACORN SELECT^SM

MAJOR PORTFOLIO CHANGES IN THE SECOND QUARTER (UNAUDITED)

	Number of Shares
	3/31/15		6/30/15
Purchases
Industrial Goods & Services
Donaldson		764,000		850,000
Expeditors International of Washington		0		269,000
Generac		0		268,000
Robert Half International		0		200,000
Information
Bankrate		595,000		871,000
Crown Castle International		0		162,000
Ultimate Software		0		78,000
Consumer Goods & Services
Fossil		120,000		174,000
Gentex		0		1,035,000
GLG Life Tech (Canada)		1,315,000		2,539,770
The Fresh Market		444,578		669,000
Vail Resorts		157,080		175,000
Health Care
VWR		325,000		376,300
Energy & Minerals
Core Labs (Netherlands)		47,000		60,000
Gulfport Energy		109,000		134,000

	Number of Shares
	3/31/15		6/30/15
Sales
Industrial Goods & Services
Ametek		754,000		703,000
Kennametal		260,000		0
LKQ		1,050,000		996,000
Nordson		264,000		230,000
Pall		163,000		0
Quanta Services		500,000		374,000
Information
Amphenol		495,000		287,000
F5 Networks		181,000		125,000
Informatica		147,000		0
Mettler-Toledo International		59,500		44,800
SBA Communications		60,000		0
Solera Holdings		390,000		350,000
Trimble Navigation		525,000		459,000
WNS - ADR		875,000		455,000
Finance
CNO Financial Group		960,000		787,000
Heath Care
Henry Schein		41,000		31,000
Seattle Genetics		148,000		0
Synageva BioPharma		121,769		0
Ultragenyx Pharmaceutical		91,000		80,000
Energy & Minerals
Cimarex Energy		45,000		0
Other Industries
EdR		275,000		256,000
Extra Space Storage		166,000		122,000
Post Properties		197,000		176,000

See accompanying notes to financial statements.

COLUMBIA ACORN SELECT^SM

STATEMENT OF INVESTMENTS (UNAUDITED), JUNE 30, 2015

Number of Shares			Value
			Equities: 97.4%
Industrial Goods & Services 29.6%
		> Machinery 16.1%
	703,000	Ametek	$	38,510,340
		Aerospace/Industrial Instruments
	850,000	Donaldson		30,430,000
		Industrial Air Filtration
	230,000	Nordson		17,914,700
		Dispensing Systems for Adhesives & Coatings
	268,000	Generac (a)(b)		10,653,000
		Standby Power Generators
				97,508,040
		> Other Industrial Services 8.8%
	996,000	LKQ (a)		30,124,020
		Alternative Auto Parts Distribution
	269,000	Expeditors International of Washington		12,402,245
		International Freight Forwarder
	200,000	Robert Half International		11,100,000
		Temporary & Permanent Staffing in Finance, Accounting & other Professions
				53,626,265
		> Industrial Distribution 2.9%
	165,000	Airgas		17,453,700
		Industrial Gas Distributor
		> Outsourcing Services 1.8%
	374,000	Quanta Services (a)		10,778,680
		Electrical Transmission & Pipeline Contracting Services
Industrial Goods & Services: Total				179,366,685
Information 24.2%
		> Business Software 6.9%
	350,000	Solera Holdings		15,596,000
		Software for Automotive Insurance Claims Processing
	149,000	Ansys (a)		13,594,760
		Simulation Software for Engineers & Designers
	78,000	Ultimate Software (a)		12,818,520
		Human Capital Management Systems
				42,009,280
		> Instrumentation 4.3%
	44,800	Mettler-Toledo International (a)		15,297,408
		Laboratory Equipment
	459,000	Trimble Navigation (a)		10,768,140
		GPS-based Instruments
				26,065,548
		> Computer Hardware & Related Equipment 2.8%
	287,000	Amphenol		16,637,390
		Electronic Connectors
		> Telecommunications Equipment 2.5%
	125,000	F5 Networks (a)		15,043,750
		Internet Traffic Management Equipment

Number of Shares			Value
		> Mobile Communications 2.2%
	162,000	Crown Castle International	$	13,008,600
		Communications Towers
		> Computer Services 2.0%
	455,000	WNS - ADR (a)		12,171,250
		Offshore Business Process Outsourcing Services
		> Business Information & Marketing Services 1.5%
	871,000	Bankrate (a)		9,136,790
		Internet Advertising for the Insurance, Credit Card & Banking Markets
		> Internet Related 1.3%
	1,635,000	Vonage (a)		8,027,850
		Business & Consumer Internet Telephony
		> Semiconductors & Related Equipment 0.7%
	423,000	Atmel		4,168,665
		Microcontrollers, Radio Frequency & Memory Semiconductors
Information: Total				146,269,123
Consumer Goods & Services 14.9%
		> Retail 5.6%
	669,000	The Fresh Market (a)(b)		21,501,660
		Specialty Food Retailer
	174,000	Fossil (a)		12,068,640
		Watch Designer & Retailer
				33,570,300
		> Travel 3.2%
	175,000	Vail Resorts		19,110,000
		Ski Resort Operator & Developer
		> Other Durable Goods 2.8%
	1,035,000	Gentex		16,994,700
		Manufacturer of Auto Parts
		> Other Consumer Services 1.8%
	268,000	Blackhawk Network (a)		11,041,600
		Third-party Distributor of Prepaid Content, Mostly Gift Cards
		> Consumer Goods Distribution 1.4%
	134,000	United Natural Foods (a)		8,533,120
		Distributor of Natural/Organic Foods to Grocery Stores
		> Food & Beverage 0.1%
	2,539,770	GLG Life Tech (Canada) (a)(b)(c)		650,702
		Producer of an All-natural Sweetener Extracted from the Stevia Plant
Consumer Goods & Services: Total				89,900,422
Finance 12.3%
		> Brokerage & Money Management 6.8%
	562,000	SEI Investments		27,554,860
		Mutual Fund Administration & Investment Management

See accompanying notes to financial statements.

COLUMBIA ACORN SELECT^SM

STATEMENT OF INVESTMENTS (UNAUDITED), CONTINUED

Number of Shares			Value
		> Brokerage & Money Management—continued
	348,000	Eaton Vance	$	13,617,240
		Specialty Mutual Funds
				41,172,100
		> Banks 3.1%
	915,000	Associated Banc-Corp		18,547,050
		Midwest Bank
		> Insurance 2.4%
	787,000	CNO Financial Group		14,441,450
		Life, Long-term Care & Medical Supplement Insurance
Finance: Total				74,160,600
Health Care 6.2%
		> Medical Supplies 4.8%
	243,000	Cepheid (a)		14,859,450
		Molecular Diagnostics
	376,300	VWR (a)		10,058,499
		Distributor of Lab Supplies
	31,000	Henry Schein (a)		4,405,720
		Distributor of Dental, Vet & Medical Products
				29,323,669
		> Biotechnology & Drug Delivery 1.4%
	80,000	Ultragenyx Pharmaceutical (a)		8,191,200
		Biotech Focused on "Ultra-Orphan" Drugs
Health Care: Total				37,514,869
Energy & Minerals 6.0%
		> Agricultural Commodities 2.7%
	1,742,424	Union Agriculture Group (Uruguay) (a)(d)(e)		16,448,482
		Farmland Operator in Uruguay
		> Oil & Gas Producers 1.2%
	118,000	Carrizo Oil & Gas (a)		5,810,320
		Oil & Gas Producer
	22,500,000	Canadian Overseas Petroleum (Canada) (a)(c)(d)		1,369,095
		Oil & Gas Exploration Offshore West Africa
	4,250,000	Petromanas (Canada) (a)(b)		187,150
		Exploring for Oil in Albania
				7,366,565
		> Mining 1.2%
	60,000	Core Labs (Netherlands) (b)		6,842,400
		Oil & Gas Reservoir Consulting

Number of Shares			Value
		> Oil Services 0.9%
	134,000	Gulfport Energy (a)	$	5,393,500
		Oil & Gas Producer Focused on Utica Shale in Ohio
Energy & Minerals: Total				36,050,947
Other Industries 4.2%
		> Real Estate 4.2%
	176,000	Post Properties		9,569,120
		Multifamily Properties
	256,000	EdR		8,028,160
		Student Housing
	122,000	Extra Space Storage		7,956,840
		Self Storage Facilities
				25,554,120
Other Industries: Total				25,554,120
Total Equities: 97.4% (Cost: $452,506,157)				588,816,766	(f)
Short-Term Investments 1.4%
	8,467,201	JPMorgan U.S. Government Money Market Fund, Agency Shares (7 day yield of 0.01%)		8,467,201
Total Short-Term Investments: 1.4% (Cost: $8,467,201)				8,467,201
Securities Lending Collateral 2.3%
	14,060,046	Dreyfus Government Cash Management Fund, Institutional Shares (7 day yield of 0.01%) (g)		14,060,046
Total Securities Lending Collateral: 2.3% (Cost: $14,060,046)				14,060,046
Total Investments: 101.1% (Cost: $475,033,404)(h)				611,344,013
Obligation to Return Collateral for Securities Loaned: (2.3)%				(14,060,046	)
Cash and Other Assets Less Liabilities: 1.2%				7,464,877
Net Assets: 100.0%			$	604,748,844

ADR - American Depositary Receipts

See accompanying notes to financial statements.

> Notes to Statement of Investments

(a) Non-income producing security.

(b) All or a portion of this security was on loan at June 30, 2015. The total market value of securities on loan at June 30, 2015 was $13,779,499.

> Notes to Statement of Investments

(c) An affiliated person of the Fund, as defined in the Investment Company Act of 1940, may include any company in which the Fund owns five percent or more of its outstanding voting shares. Holdings and transactions in these affiliated companies during the period ended June 30, 2015, are as follows:

Security	Balance of Shares Held 12/31/14		Purchases/ Additions		Sales/ Reductions		Balance of Shares Held 6/30/15		Value		Dividend
Canadian Overseas Petroleum		22,500,000		-		-		22,500,000	$	1,369,095	$	-
GLG Life Tech		1,500,000		1,224,770		185,000		2,539,770		650,702
Petrodorado Energy (1)		3,370,000		-		3,370,000		-		-		-
Total of Affiliated Transactions		27,370,000		1,224,770		3,555,000		25,039,770	$	2,019,797	$	-

(1) At June 30, 2015, 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, 2015, was $17,688,954 and $2,019,797, respectively. Investments in affiliated companies represented 0.33% of the Fund's total net assets at June 30, 2015.

(d) Denotes a restricted security, which is subject to restrictions on resale under federal securities laws. These securities are valued at fair value determined in good faith under consistently applied procedures established by the Fund's Board of Trustees. At June 30, 2015, the market value of these securities amounted to $17,817,577, which represented 2.95% of total net assets. Additional information on these securities is as follows:

Security	Acquisition Dates	Shares/Units		Cost		Value
Union Agriculture Group	12/8/10-6/27/12		1,742,424	$	20,000,000	$	16,448,482
Canadian Overseas Petroleum	11/24/10		22,500,000		9,596,330		1,369,095
				$	29,596,330	$	17,817,577

(e) Illiquid security.

(f) On June 30, 2015, the market value of foreign securities represented 4.22% of total net assets. The Fund's foreign portfolio was diversified as follows:

Country	Value		Percentage of Net Assets
Uruguay	$	16,448,483		2.72
Netherlands		6,842,400		1.13
Canada		2,206,947		0.37
Total Foreign Portfolio	$	25,497,830		4.22

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

(h) At June 30, 2015, for federal income tax purposes, the cost of investments was approximately $475,033,404 and net unrealized appreciation was $136,310,609 consisting of gross unrealized appreciation of $168,433,250 and gross unrealized depreciation of $32,122,641.

Fair Value Measurements

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

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

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

The Committee is responsible for applying the Trust's Portfolio Pricing Policy and the CWAM pricing procedures (the Policies), which are approved by and subject to the oversight of the Board.

See accompanying notes to financial statements.

COLUMBIA ACORN SELECT^SM

STATEMENT OF INVESTMENTS (UNAUDITED), CONTINUED

> Notes to Statement of Investments

require fair valuation and fair value techniques; circumstances under which securities will be deemed to pose a potential for stale pricing, including when securities are illiquid, restricted, or in default; and certain delegations of authority to determine fair values to the Fund's investment manager. The Committee may also meet to discuss additional valuation matters, which may include review of back-testing results, review of time-sensitive information or approval of other valuation related actions, and to review the appropriateness of the Policies.

The following table summarizes the inputs used, as of June 30, 2015, in valuing the Fund's assets:

Investment Type	Quoted Prices (Level 1)		Other Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Equities
Industrial Goods & Services	$	179,366,685	$	-	$	-	$	179,366,685
Information		146,269,123		-		-		146,269,123
Consumer Goods & Services		89,900,422		-		-		89,900,422
Finance		74,160,600		-		-		74,160,600
Health Care		37,514,869		-		-		37,514,869
Energy & Minerals		18,233,370		1,369,095		16,448,482		36,050,947
Other Industries		25,554,120		-		-		25,554,120
Total Equities		570,999,189		1,369,095		16,448,482		588,816,766
Total Short-Term Investments		8,467,201		-		-		8,467,201
Total Securities Lending Collateral		14,060,046		-		-		14,060,046
Total Investments	$	593,526,436	$	1,369,095	$	16,448,482	$	611,344,013

There were no transfers of financial assets between levels during the period.

The following table reconciles asset balances for the period ending June 30, 2015, in which significant observable and/or unobservable inputs (Level 3) were used in determining value:

Investments in Securities	Balance as of December 31, 2014		Realized Gain (Loss)		Change in Unrealized Appreciation (Depreciation)		Purchases		Sales		Transfers into Level 3		Transfers out of Level 3		Balance as of June 30, 2015
Equities
Energy & Minerals	$	15,908,331	$	-	$	540,151	$	-	$	-	$	-	$	-	$	16,448,482

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

The change in unrealized appreciation attributed to securities owned at June 30, 2015, which were valued using significant unobservable inputs (Level 3), amounted to $540,151.

Quantitative information pertaining to Level 3 unobservable fair value measurements

Fair Value at
June 30, 2015

Valuation Technique(s)

Unabservable Input(s)

Range (Weighted
Average)

Equities
Energy & Minerals

16,448,482

Market comparable
companies

Discount for lack
of marketability

%—23%

See accompanying notes to financial statements.

COLUMBIA THERMOSTAT FUND^SM

STATEMENT OF INVESTMENTS (UNAUDITED), JUNE 30, 2015

Number of Shares			Value
		> Affiliated Bond Funds 75.1%
	35,516,291	Columbia Short Term Bond Fund, Class I Shares (a)	$	353,387,100
	17,854,552	Columbia Income Opportunities Fund, Class I Shares (a)		177,474,246
	32,127,882	Columbia U.S. Government Mortgage Fund, Class I Shares (a)		177,024,633
	19,415,464	Columbia Intermediate Bond Fund, Class I Shares (a)		176,874,874
Total Affiliated Bond Funds: (Cost: $879,787,703)				884,760,853
		> Affiliated Stock Funds 25.0%
	1,355,680	Columbia Acorn International, Class I Shares (a)		59,066,971
	2,645,290	Columbia Contrarian Core Fund, Class I Shares (a)		58,989,967
	3,184,853	Columbia Dividend Income Fund, Class I Shares (a)		58,919,778
	1,606,465	Columbia Select Large Cap Growth Fund, Class I Shares (a)(b)		29,623,205
	909,100	Columbia Acorn Fund, Class I Shares (a)(b)		29,573,038
	1,341,246	Columbia Acorn Select, Class I Shares (a)(b)		29,507,415
	1,383,097	Columbia Large Cap Enhanced Core Fund, Class I Shares (a)		29,487,629
Total Affiliated Stock Funds: (Cost: $266,299,011)				295,168,003

Number of Shares			Value
		> Short-Term Investments 0.5%
	5,691,503	JPMorgan U.S. Government Money Market Fund, Agency Shares (7 day yield of 0.01%)	$	5,691,503
Total Short-Term Investments: (Cost: $5,691,503)				5,691,503
Total Investments: 100.6% (Cost: $1,151,778,217)(c)				1,185,620,359
Cash and Other Assets Less Liabilities: (0.6)%				(7,318,809	)
Net Assets: 100.0%			$	1,178,301,550

> Notes to Statement of Investments

(a) An affiliated person of the Fund, as defined in the Investment Company Act of 1940, may include any company in which the Fund owns five percent or more of its outstanding voting shares. Holdings and transactions in these affiliated companies during the period ended June 30, 2015, are as follows:

Security	Balance of Shares Held 12/31/14		Purchases/ Additions		Sales/ Reductions		Balance of Shares Held 6/30/15		Value		Dividend
Columbia Short Term Bond Fund, Class I Shares		42,849,246		2,763,972		10,096,927		35,516,291	$	353,387,100	$	2,222,711
Columbia Income Opportunities Fund, Class I Shares		21,780,174		1,600,546		5,526,168		17,854,552		177,474,246		5,023,196
Columbia U.S. Government Mortgage Fund, Class I Shares		28,883,507		7,407,947		4,163,572		32,127,882		177,024,633		2,621,759
Columbia Intermediate Bond Fund, Class I Shares		28,994,280		1,854,895		11,433,711		19,415,464		176,874,874		3,236,595
Columbia Acorn International, Class I Shares		898,450		848,428		391,198		1,355,680		59,066,971		-
Columbia Contrarian Core Fund, Class I Shares		1,291,662		1,933,262		579,634		2,645,290		58,989,967		-
Columbia Dividend Income Fund, Class I Shares		1,962,468		1,978,105		755,720		3,184,853		58,919,778		489,414
Columbia Select Large Cap Growth Fund, Class I Shares		1,023,561		1,065,033		482,129		1,606,465		29,623,205		-
Columbia Acorn Fund, Class I Shares		879,308		420,682		390,890		909,100		29,573,038		-
Columbia Acorn Select, Class I Shares		836,113		888,927		383,794		1,341,246		29,507,415		-
Columbia Large Cap Enhanced Core Fund, Class I Shares		870,296		861,625		348,824		1,383,097		29,487,629		207,636
Total of Affiliated Transactions		130,269,065		21,623,422		34,552,567		117,339,920	$	1,179,928,856	$	13,801,311

The aggregate cost and value of these companies at June 30, 2015, was $1,146,086,714 and $1,179,928,856, respectively. Investments in affiliated companies represented 100.14% of the Fund's total net assets at June 30, 2015.

(b) Non-income producing security.

(c) At June 30, 2015, for federal income tax purposes, the cost of investments was approximately $1,151,778,217 and net unrealized appreciation was $33,842,142 consisting of gross unrealized appreciation of $34,822,062 and gross unrealized depreciation of $979,920.

See accompanying notes to financial statements.

COLUMBIA THERMOSTAT FUND^SM

STATEMENT OF INVESTMENTS (UNAUDITED), CONTINUED

> Notes to Statement of Investments

Fair Value Measurements

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

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

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

Examples of the types of securities in which the Fund would typically invest and how they are classified within this hierarchy are as follows. Typical Level 1 securities include mutual funds whose NAVs are published each day.

CWAM's Valuation Committee (the Committee), is responsible for applying the Trust's Portfolio Pricing Policy and the CWAM pricing procedures (the Policies), which are approved by and subject to the oversight of the Board.

The following table summarizes the inputs used, as of June 30, 2015, in valuing the Fund's assets:

Investment Type	Quoted Prices (Level 1)		Other Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Total Affiliated Bond Funds	$	884,760,853	$	-	$	-	$	884,760,853
Total Affiliated Stock Funds		295,168,003		-		-		295,168,003
Total Short-Term Investments		5,691,503		-		-		5,691,503
Total Investments	$	1,185,620,359	$	-	$	-	$	1,185,620,359

There were no transfers of financial assets between levels during the period.

See accompanying notes to financial statements.

COLUMBIA ACORN EMERGING MARKETS FUND^SM

MAJOR PORTFOLIO CHANGES IN THE SECOND QUARTER (UNAUDITED)

	Number of Shares
	3/31/15		6/30/15
Purchases
Asia
> China
51job - ADR		0		66,000
Canvest Environment Protection		0		9,263,000
CapitaLand Retail China Trust		0		3,757,000
CAR Inc		0		3,668,000
Chongqing Rural Commercial Bank		0		5,600,000
Jiangnan Group		0		15,338,000
NewOcean Energy		11,330,000		13,784,000
Phoenix Healthcare Group		0		2,265,000
Phoenix New Media - ADR		257,000		464,000
Shanghai Industrial		0		1,207,000
TravelSky Technology		0		2,459,000
Xinhua Winshare Publishing		2,146,000		3,303,000
> Taiwan
Far EasTone Telecom		0		1,900,000
Largan Precision		55,000		59,000
Novatek Microelectronics		0		881,000
Silergy		0		160,000
Vanguard International Semiconductor		2,814,000		4,177,000
Voltronic Power		404,000		424,000
> India
Amara Raja		0		110,352
Container Corporation of India		140,070		160,788
> Indonesia
Surya Citra Media		0		18,149,000
> Thailand
Mega Lifesciences		0		6,899,100
> Singapore
China Everbright Water		0		5,345,200
SIIC Environment		0		42,467,800
> Malaysia
Astro Malaysia Holdings		114,500		5,300,000
Latin America
> Mexico
Grupo Aeroportuario del Sureste - ADR		40,525		48,525
Qualitas		2,500,000		3,748,000
Other Countries
> Egypt
Commercial International Bank of Egypt		593,000		975,991
Europe
> United Kingdom
PureCircle		580,790		736,860

	Number of Shares
	3/31/15		6/30/15
Sales
Asia
> China
AMVIG Holdings		31,000,000		25,200,000
China Everbright International		3,128,000		2,340,000
Sino Biopharmaceutical		4,925,000		0
WuXi PharmaTech - ADR		121,000		117,000
> Taiwan
Advantech		598,988		575,988
Chroma Ate		2,050,990		775,990
Ginko International		360,000		340,000
PChome Online		570,000		440,000
President Chain Store		1,240,000		940,000
> India
Bosch		17,632		0
United Breweries		353,739		318,483
> Indonesia
Ace Indonesia		82,889,190		0
Link Net		11,800,000		10,600,000
Matahari Department Store		4,248,600		4,068,700
Mayora Indah		2,300,000		0
MNC Sky Vision		61,839,700		59,276,600
Tower Bersama Infrastructure		6,744,300		6,406,300
> Philippines
Melco Crown (Philippines) Resorts		41,313,300		34,926,300
Puregold Price Club		5,613,200		5,087,200
Robinsons Retail Holdings		2,636,090		2,451,090
> Thailand
Robinson Department Store		3,737,700		3,271,700
Samui Airport Property Fund		10,016,800		8,732,800
> Singapore
Petra Foods		1,829,000		1,397,400
> Hong Kong
Melco International		5,817,000		2,616,000
Sa Sa International		5,583,799		0
> Korea
Grand Korea Leisure		98,149		0
Koh Young Technology		256,088		241,088
The Basic House		421,000		0
> Malaysia
7-Eleven Malaysia Holdings		12,777,900		10,000,000
Aeon		4,006,700		0
> Japan
Kansai Paint		310,760		0

See accompanying notes to financial statements.

COLUMBIA ACORN EMERGING MARKETS FUND^SM

MAJOR PORTFOLIO CHANGES IN THE SECOND QUARTER (UNAUDITED), CONTINUED

	Number of Shares
	3/31/15		6/30/15
Sales (continued)
Latin America
> Brazil
Beadell Resources		335,646		0
Localiza Rent A Car		677,970		595,970
> Chile
Forus		1,943,078		1,586,000
Other Countries
> South Africa
Coronation Fund Managers		1,955,513		1,795,460
Mr. Price		288,041		0
Rand Merchant Insurance		2,599,148		2,262,148
> United States
Bladex		171,094		140,000
Europe
> United Kingdom
Cable and Wireless		10,175,965		7,207,000
> France
Eutelsat		200,000		0
> Italy
Pirelli		270,882		0
> Spain
Prosegur		1,148,390		0
> Sweden
Hexagon		207,455		0

See accompanying notes to financial statements.

COLUMBIA ACORN EMERGING MARKETS FUND^SM

STATEMENT OF INVESTMENTS (UNAUDITED), JUNE 30, 2015

Number of Shares			Value
			Equities: 97.0%
Asia 71.8%
		> China 21.3%
	25,200,000	AMVIG Holdings	$	13,003,851
		Chinese Tobacco Packaging Material Supplier
	3,668,000	CAR Inc (a)		7,795,304
		Consolidator of Chinese Auto Rental Sector
	126,613	BitAuto - ADR (a)		6,463,594
		Automotive Information Website for Buyers & Dealers
	13,784,000	NewOcean Energy		6,397,958
		Southern China Liquefied Petroleum Gas Distributor
	11,951,000	Sihuan Pharmaceuticals (b)		5,397,998
		Chinese Generic Drug Manufacturer
	117,000	WuXi PharmaTech - ADR (a)		4,944,420
		Contract Research Organization in China
	9,263,000	Canvest Environment Protection (a)		4,900,661
		Guangdong Waste-to-energy Operator
	3,757,000	CapitaLand Retail China Trust		4,853,681
		China Commercial Property Real Estate Investment Trust
	5,600,000	Chongqing Rural Commercial Bank		4,479,274
		Rural Commercial Bank
	15,338,000	Jiangnan Group		4,406,955
		Cable & Wire Manufacturer
	2,265,000	Phoenix Healthcare Group		4,308,438
		Private Hospital Management Group
	2,340,000	China Everbright International		4,190,936
		Municipal Waste Operator
	1,207,000	Shanghai Industrial		4,086,673
		Shanghai State Owned Enterprise
	3,303,000	Xinhua Winshare Publishing		3,957,433
		Sichuan Publisher, Distributor & Retailer
	464,000	Phoenix New Media - ADR (a)		3,674,880
		Internet Advertising
	2,459,000	TravelSky Technology		3,617,232
		Chinese Air Travel Transaction Processor
	66,000	51job - ADR (a)(c)		2,193,840
		Integrated Human Resource Services
				88,673,128
		> Taiwan 14.3%
	440,000	PChome Online		7,263,149
		Taiwanese Internet Retail Company
	59,000	Largan Precision		6,734,898
		Mobile Device Camera Lenses & Modules
	420,000	St. Shine Optical		6,676,176
		Disposable Contact Lens Original Equipment Manufacturer
	4,177,000	Vanguard International Semiconductor		6,665,766
		Semiconductor Foundry
	940,000	President Chain Store		6,608,620
		Convenience Chain Store Operator in Taiwan

Number of Shares			Value
	424,000	Voltronic Power	$	5,343,782
		Uninterruptible Power Supply Products
	1,900,000	Far EasTone Telecom		4,592,732
		Mobile Operator in Taiwan
	340,000	Ginko International		4,273,398
		Contact Lens Maker in China
	881,000	Novatek Microelectronics		4,249,397
		Display Related Integrated Circuit Designer
	575,988	Advantech		3,954,931
		Industrial PC & Components
	775,990	Chroma Ate		1,714,991
		Automatic Test Systems, Testing & Measurement Instruments
	160,000	Silergy		1,648,034
		Chinese Provider of Analog & Mixed Digital Integrated Circuits
				59,725,874
		> India 10.6%
	2,422,982	Zee Entertainment Enterprises		13,984,733
		Indian Programmer of Pay Television Content
	1,737,269	Adani Ports & Special Economic Zone		8,384,721
		Indian West Coast Shipping Port
	190,350	Colgate Palmolive India		6,092,000
		Consumer Products in Oral Care
	730,342	Bharti Infratel		5,126,616
		Communications Towers
	318,483	United Breweries		4,663,142
		Indian Brewer
	160,788	Container Corporation of India		4,229,011
		Railway Cargo Services
	110,352	Amara Raja		1,527,917
		Indian Maker of Auto & Industrial Batteries, Mostly for the Replacement Market
				44,008,140
		> Indonesia 6.4%
	59,276,600	MNC Sky Vision (a)		6,446,733
		Satellite Pay TV Operator in Indonesia
	4,068,700	Matahari Department Store		5,042,738
		Department Store Chain in Indonesia
	6,406,300	Tower Bersama Infrastructure		4,432,636
		Communications Towers
	10,600,000	Link Net (a)		4,034,877
		Fixed Broadband & Cable TV Service Provider
	18,149,000	Surya Citra Media		3,905,914
		Free to Air TV Station in Indonesia
	66,827,701	Arwana Citramulia		2,656,567
		Ceramic Tiles for Home Decoration
				26,519,465
		> Philippines 4.2%
	56,400,000	RFM		5,186,260
		Flour, Bread, Pasta & Ice Cream Manufacturer/Distributor in the Philippines
	5,087,200	Puregold Price Club		4,172,337
		Supermarket Operator in the Philippines

See accompanying notes to financial statements.

COLUMBIA ACORN EMERGING MARKETS FUND^SM

STATEMENT OF INVESTMENTS (UNAUDITED), CONTINUED

Number of Shares			Value
		> Philippines—continued
	2,451,090	Robinsons Retail Holdings	$	4,047,098
		Multi-format Retailer in the Philippines
	34,926,300	Melco Crown (Philippines) Resorts (a)		3,964,174
		Integrated Resort Operator in Manila
				17,369,869
		> Thailand 4.1%
	8,732,800	Samui Airport Property Fund		4,679,832
		Thai Airport Operator
	22,534,651	Home Product Center		4,495,459
		Home Improvement Retailer
	3,271,700	Robinson Department Store		4,328,379
		Department Store Operator in Thailand
	6,899,100	Mega Lifesciences		3,796,406
		Manufacturer of Health Supplements & Pharmaceutical Products
				17,300,076
		> Singapore 3.3%
	42,467,800	SIIC Environment (a)		6,143,886
		Waste Water Treatment Operator
	5,345,200	China Everbright Water (a)		3,911,003
		Waste Water Treatment Operator
	1,397,400	Petra Foods		3,631,362
		Chocolate Manufacturer in Southeast Asia
				13,686,251
		> Hong Kong 2.4%
	3,698,000	Vitasoy International		6,297,269
		Hong Kong Soy Food Brand
	2,616,000	Melco International		3,693,347
		Macau Casino Operator
				9,990,616
		> Korea 2.1%
	241,088	Koh Young Technology		8,873,171
		Inspection Systems for Printed Circuit Boards
		> Malaysia 2.0%
	5,300,000	Astro Malaysia Holdings		4,325,150
		Pay TV Operator in Malaysia
	10,000,000	7-Eleven Malaysia Holdings		4,240,657
		Exclusive 7-Eleven Franchisor for Malaysia
				8,565,807
		> Cambodia 1.1%
	6,300,000	Nagacorp		4,638,174
		Casino & Entertainment Complex in Cambodia
Asia: Total				299,350,571
Latin America 10.7%
		> Mexico 4.1%
	48,525	Grupo Aeroportuario del Sureste - ADR		6,884,242
		Mexican Airport Operator

Number of Shares			Value
	3,748,000	Qualitas (a)	$	6,202,353
		Auto Insurer in Mexico & Central America
	2,747,000	Hoteles City Express (a)		4,005,805
		Budget Hotel Operator in Mexico
				17,092,400
		> Brazil 3.7%
	595,970	Localiza Rent A Car		5,900,086
		Car Rental
	1,430,100	Odontoprev		4,981,500
		Dental Insurance
	280,000	Linx		4,336,303
		Retail Management Software in Brazil
				15,217,889
		> Colombia 1.5%
	6,047,782	Isagen		6,453,530
		Colombian Electricity Provider
		> Chile 1.4%
	1,586,000	Forus		5,678,365
		Multi-brand Latin American Wholesaler & Retailer
Latin America: Total				44,442,184
Other Countries 7.6%
		> South Africa 4.8%
	1,795,460	Coronation Fund Managers (c)		12,162,079
		South African Fund Manager
	2,262,148	Rand Merchant Insurance		7,896,879
		Directly Sold Property & Casualty Insurance; Holdings in other Insurers
				20,058,958
		> Egypt 1.7%
	975,991	Commercial International Bank of Egypt		7,160,567
		Private Universal Bank in Egypt
		> United States 1.1%
	140,000	Bladex		4,505,200
		Latin American Trade Financing House
Other Countries: Total				31,724,725
Europe 6.9%
		> United Kingdom 2.9%
	7,207,000	Cable and Wireless		7,541,783
		Telecommunications Service Provider in the Caribbean
	736,860	PureCircle (a)(c)		4,689,054
		Natural Sweeteners
				12,230,837
		> Kazakhstan 2.6%
	1,268,483	Halyk Savings Bank of Kazakhstan - GDR		10,782,106
		Retail Bank & Insurer in Kazakhstan

See accompanying notes to financial statements.

Number of Shares			Value
		> Finland 1.4%
	290,000	Tikkurila	$	5,764,553
		Decorative & Industrial Paint in Scandinavia, Central & Eastern Europe
Europe: Total				28,777,496
Total Equities: 97.0% (Cost: $404,387,769)				404,294,976	(d)
Short-Term Investments 3.4%
	13,916,492	JPMorgan U.S. Government Money Market Fund, IM Shares (7 day yield of 0.01%)		13,916,492
Total Short-Term Investments: 3.4% (Cost: $13,916,492)				13,916,492

Number of Shares			Value
Securities Lending Collateral 0.6%
	2,703,540	Dreyfus Government Cash Management Fund, Institutional Shares (7 day yield of 0.01%) (e)	$	2,703,540
Total Securities Lending Collateral: 0.6% (Cost: $2,703,540)				2,703,540
Total Investments: 101.0% (Cost: $421,007,801)(f)				420,915,008
Obligation to Return Collateral for Securities Loaned: (0.6)%				(2,703,540	)
Cash and Other Assets Less Liabilities: (0.4)%				(1,339,423	)
Net Assets: 100.0%			$	416,872,045

ADR - American Depositary Receipts

GDR - Global Depositary Receipts

> Notes to Statement of Investments

(a) Non-income producing security.

(b) Illiquid security.

(c) All or a portion of this security was on loan at June 30, 2015. The total market value of securities on loan at June 30, 2015 was $2,610,061.

(d) On June 30, 2015, the Fund's total equity investments were denominated in currencies as follows:

Currency	Value		Percentage of Net Assets
Hong Kong Dollar	$	81,171,504		19.5
Taiwan Dollar		59,725,874		14.3
Indian Rupee		44,008,140		10.5
U.S. Dollar		39,448,281		9.5
Indonesian Rupiah		26,519,464		6.4
Other currencies less than 5% of total net assets		153,421,713		36.8
Total Equities	$	404,294,976		97.0

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

(f) At June 30, 2015, for federal income tax purposes, the cost of investments was approximately $421,007,801 and net unrealized depreciation was $92,793 consisting of gross unrealized appreciation of $47,147,719 and gross unrealized depreciation of $47,240,512.

Fair Value Measurements

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

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

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

See accompanying notes to financial statements.

COLUMBIA ACORN EMERGING MARKETS FUND^SM

STATEMENT OF INVESTMENTS (UNAUDITED), CONTINUED

> Notes to Statement of Investments

The Committee is responsible for applying the Trust's Portfolio Pricing Policy and the CWAM pricing procedures (the Policies), which are approved by and subject to the oversight of the Board.

The following table summarizes the inputs used, as of June 30, 2015, in valuing the Fund's assets:

Investment Type	Quoted Prices (Level 1)		Other Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Equities
Asia	$	17,276,734	$	276,675,839	$	5,397,998	$	299,350,571
Latin America		44,442,184		-		-		44,442,184
Other Countries		4,505,200		27,219,525		-		31,724,725
Europe		-		28,777,496		-		28,777,496
Total Equities		66,224,118		332,672,860		5,397,998		404,294,976
Total Short-Term Investments		13,916,492		-		-		13,916,492
Total Securities Lending Collateral		2,703,540		-		-		2,703,540
Total Investments	$	82,844,150	$	332,672,860	$	5,397,998	$	420,915,008

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

The following table reconciles asset balances for the period ending June 30, 2015, in which significant observable and/or unobservable inputs (Level 3) were used in determining value:

Investments in Securities	Balance as of December 31, 2014		Realized Gain (Loss)		Change in Unrealized Appreciation (Depreciation)			Purchases		Sales		Transfers into Level 3		Transfers out of Level 3		Balance as of June 30, 2015
Equities
Asia	$	-	$	-	$	(2,551,314	)	$	-	$	-	$	7,949,312	$	-	$	5,397,998

See accompanying notes to financial statements.

> Notes to Statement of Investments

The change in unrealized depreciation attributed to securities owned at June 30, 2015, which were valued using significant unobservable inputs (Level 3), amounted to $2,551,314.

Quantitative information pertaining to Level 3 unobservable fair value measurements

Fair Value at
June 30, 2015

Valuation Technique(s)

Unabservable Input(s)

Range (Weighted
Average)

Equities
Asia

5,397,998

Float price
with market index

Discount for lack
of liquidity

Financial assets were transferred from Level 2 to Level 3 as trading halted during the period. As a result, as of period end, management determined to value the security(s) under consistently applied procedures established by and under the general supervision of the Board of Trustees.

The following table shows transfers between Level 2 and Level 3 of the fair value hierarchy:

Transfers In				Transfers Out
Level 2		Level 3		Level 2		Level 3
$	-	$	7,949,312	$	7,949,312	$	-

Transfers in and/or out of Level 3 are determined based on the fair value at the beginning of the period for security positions held throughout the period.

Certain securities classified as Level 3 are valued by the Committee at fair value, using a market approach, as determined in good faith under consistently applied procedures established by and under the general supervision of the Board. To determine fair value for these securities, for which no market exists, the Committee utilizes the valuation technique it deems most appropriate in the circumstances, using some unobservable inputs, which may include, but are not limited to estimated earnings of the company and the position of the security within the company's capital structure. The Committee also may use some observable inputs, which may include, but are not limited to, trades of similar securities or indicies. Significant increases or decreases to any of these inputs could result in a significantly lower or higher fair value measurement.

See accompanying notes to financial statements.

COLUMBIA ACORN EMERGING MARKETS FUND^SM

PORTFOLIO DIVERSIFICATION (UNAUDITED)

At June 30, 2015, the Fund's portfolio investments as a percentage of net assets were diversified as follows:

	Value		Percentage of Net Assets
> Consumer Goods & Services
Retail	$	49,834,234		12.0
Food & Beverage		24,467,088		5.9
Travel		17,701,194		4.2
Casinos & Gaming		12,295,695		2.9
Consumer Goods Distribution		9,888,407		2.4
Other Durable Goods		1,527,916		0.4
		115,714,534		27.8
> Information
Mobile Communications		14,151,983		3.4
Entertainment Programming		13,984,733		3.4
Semiconductors & Related Equipment		12,563,198		3.0
Internet Related		12,332,314		3.0
Satellite Broadcasting & Services		10,771,883		2.6
Instrumentation		10,588,162		2.5
Computer Hardware & Related Equipment		9,298,713		2.2
Business Software		7,953,536		1.9
Telephone & Data Services		7,541,783		1.8
Telecommunications Equipment		6,734,898		1.6
Cable TV		4,034,877		1.0
TV Broadcasting		3,905,913		0.9
		113,861,993		27.3
> Finance
Banks		26,927,146		6.5
Insurance		19,080,732		4.6
Brokerage & Money Management		12,162,080		2.9
		58,169,958		14.0
> Industrial Goods & Services
Industrial Materials & Specialty Chemicals		21,424,971		5.1
Water		10,054,889		2.4
Waste Management		9,091,597		2.2
Other Industrial Services		8,384,721		2.0
Electrical Components		4,406,955		1.1
Conglomerates		4,086,674		1.0
		57,449,807		13.8

	Value			Percentage of Net Assets
> Other Industries
Transportation	$	15,793,086			3.8
Regulated Utilities		6,453,530			1.5
Real Estate		4,853,681			1.2
		27,100,297			6.5
> Health Care
Medical Supplies		10,949,574			2.6
Pharmaceuticals		10,342,418			2.5
Hospital Management		4,308,438			1.0
		25,600,430			6.1
> Energy & Minerals
Oil Refining, Marketing & Distribution		6,397,957			1.5
		6,397,957			1.5
Total Equities:		404,294,976			97.0
Short-Term Investments:		13,916,492			3.4
Securities Lending Collateral:		2,703,540			0.6
Total Investments:		420,915,008			101.0
Obligation to Return Collateral for Securities Loaned:		(2,703,540	)		(0.6	)
Cash and Other Assets Less Liabilities:		(1,339,423	)		(0.4	)
Net Assets:	$	416,872,045			100.0

See accompanying notes to financial statements.

COLUMBIA ACORN EUROPEAN FUND^SM

MAJOR PORTFOLIO CHANGES IN THE SECOND QUARTER (UNAUDITED)

	Number of Shares
	3/31/15		6/30/15
Purchases
Europe
> United Kingdom
Abcam		63,970		66,010
Aggreko		26,960		33,220
Assura		1,667,855		1,811,485
AVEVA		18,550		20,150
Cable and Wireless		950,000		1,043,540
Cambian		199,280		204,460
Charles Taylor		241,240		384,788
Dialight		55,260		70,640
Domino's Pizza UK & Ireland		37,830		44,010
Elementis		95,860		114,720
Fidessa Group		18,470		23,460
Halfords		76,159		81,000
Halma		39,570		46,890
Ocado		92,240		95,010
Polypipe		101,620		125,110
PureCircle		53,548		97,930
Regus		0		137,120
Rightmove		9,670		10,760
WH Smith		32,710		35,360
> France
AKKA Technologies		13,874		17,288
Bonduelle		15,690		19,310
Cegedim		14,480		15,360
Eurofins Scientific		1,540		1,830
Eutelsat		18,960		32,020
Neopost		16,720		27,860
Saft		12,681		13,821
> Germany
Aurelius		23,640		27,900
Elringklinger		13,410		18,950
MTU Aero Engines		7,000		9,730
NORMA Group		16,360		19,770
Rational		1,200		1,430
Telefonica Deutschland		70,780		94,780
Wirecard		14,360		18,900
> Sweden
Hexagon		21,733		24,633
Mekonomen		18,960		25,800
Modern Times Group		16,160		21,470
Recipharm		29,580		44,030
Sweco		41,270		63,050
Swedish Match		17,970		25,662
Unibet		11,851		14,591

	Number of Shares
	3/31/15		6/30/15
> Finland
Konecranes		15,240		25,836
Munksjo		68,380		185,880
Sponda		123,070		160,990
Tikkurila		28,801		33,751
> Netherlands
Aalberts Industries		26,330		32,560
Arcadis		12,819		20,005
Brunel		27,271		35,741
Core Labs		3,920		4,400
Gemalto		5,490		6,060
Vopak		0		11,490
> Spain
Bolsas y Mercados Españoles		10,370		12,520
Distribuidora Internacional de Alimentación		169,200		202,320
Prosegur		109,950		142,750
> Switzerland
INFICON		1,150		1,530
Partners Group		3,250		4,480
> Denmark
SimCorp		15,490		25,640
William Demant Holding		0		14,000
> Norway
Atea		36,180		62,050
Orkla		70,370		87,370
> Italy
Hera		0		105,433
> Belgium
EVS Broadcast Equipment		11,070		19,420

See accompanying notes to financial statements.

COLUMBIA ACORN EUROPEAN FUND^SM

MAJOR PORTFOLIO CHANGES IN THE SECOND QUARTER (UNAUDITED), CONTINUED

	Number of Shares
	3/31/15		6/30/15
Sales
Europe
> United Kingdom
Babcock International		56,990		49,910
Charles Taylor		96,338		0
Jardine Lloyd Thompson Group		38,560		35,000
RPS Group		120,090		0
Whitbread		7,954		0
> France
Norbert Dentressangle		2,690		0
> Spain
Viscofan		10,430		8,720
> Switzerland
Geberit		2,740		2,530
> Italy
Pirelli		24,990		0

See accompanying notes to financial statements.

COLUMBIA ACORN EUROPEAN FUND^SM

STATEMENT OF INVESTMENTS (UNAUDITED), JUNE 30, 2015

Number of Shares			Value
			Equities: 93.1%
Europe 93.1%
		> United Kingdom 30.9%
	1,811,485	Assura	$	1,558,347
		UK Primary Health Care Property Developer
	384,788	Charles Taylor		1,330,116
		Insurance Services
	24,357	Spirax Sarco		1,298,533
		Steam Systems for Manufacturing & Process Industries
	1,043,540	Cable and Wireless		1,092,015
		Telecommunications Service Provider in the Caribbean
	204,460	Cambian		962,970
		Mental Health Facilities & Programs
	35,360	WH Smith		848,947
		Newsprint, Books & General Stationery Retailer
	49,910	Babcock International		846,948
		Public Sector Outsourcer
	23,460	Fidessa Group		838,600
		Software for Financial Trading Systems
	33,220	Aggreko		751,114
		Temporary Power & Temperature Control Services
	81,000	Halfords		671,992
		UK Retailer of Leisure Goods & Auto Parts
	95,010	Ocado (a)		665,659
		Online Grocery Retailer
	97,930	PureCircle (a)(b)		623,184
		Natural Sweeteners
	35,000	Jardine Lloyd Thompson Group		574,135
		International Business Insurance Broker
	20,150	AVEVA		572,425
		Engineering Software
	70,640	Dialight		567,175
		LED Products for Hazardous & Industrial Environments
	137,120	Regus		562,755
		Rental of Office Space in Full Service Business Centers
	46,890	Halma		561,410
		Health & Safety Sensor Technology
	10,760	Rightmove		554,031
		Internet Real Estate Listings
	44,010	Domino's Pizza UK & Ireland		537,301
		Pizza Delivery in the UK, Ireland & Germany
	66,010	Abcam		537,260
		Online Sales of Antibodies
	125,110	Polypipe		533,712
		Manufacturer of Plastic Piping & Fittings
	225,231	Connect Group		501,645
		Newspaper & Magazine Distributor
	114,720	Elementis		462,531
		Specialty Chemicals
				17,452,805

Number of Shares			Value
		> France 10.2%
	27,860	Neopost	$	1,198,749
		Postage Meter Machines
	32,020	Eutelsat		1,033,442
		Fixed Satellite Services
	15,360	Cegedim (a)		648,318
		Medical Market Research/IT Services
	17,288	AKKA Technologies		614,825
		Engineering Consultancy
	1,830	Eurofins Scientific		557,172
		Food, Pharmaceuticals & Materials Screening & Testing
	13,821	Saft		539,292
		Niche Battery Manufacturer
	19,310	Bonduelle		490,833
		Producer of Canned, Deep-frozen & Fresh Vegetables
	263,340	HiPay Group (a)		349,366
		Online Payment Processor in Europe
	263,340	Hi-Media (a)(b)		320,007
		Online Advertiser in Europe
				5,752,004
		> Germany 9.6%
	27,900	Aurelius		1,192,695
		European Turnaround Investor
	19,770	NORMA Group		999,430
		Clamps for Automotive & Industrial Applications
	9,730	MTU Aero Engines		915,202
		Airplane Engine Components & Services
	18,900	Wirecard (b)		723,777
		Online Payment Processing & Risk Management			��
	94,780	Telefonica Deutschland		546,290
		Mobile & Fixed-line Communications in Germany
	1,430	Rational		525,221
		Commercial Ovens
	18,950	Elringklinger		509,463
		Automobile Components
				5,412,078
		> Sweden 9.5%
	24,633	Hexagon		892,628
		Design, Measurement & Visualization Software & Equipment
	14,591	Unibet		888,853
		European Online Gaming Operator
	63,050	Sweco		827,118
		Engineering Consultants
	44,030	Recipharm		823,254
		Contract Development Manufacturing Organization
	25,662	Swedish Match		729,941
		Swedish Snus
	25,800	Mekonomen		630,228
		Nordic Integrated Wholesaler/Retailer of Automotive Parts & Service
	21,470	Modern Times Group (b)		575,997
		Nordic TV Broadcaster
				5,368,019

See accompanying notes to financial statements.

COLUMBIA ACORN EUROPEAN FUND^SM

STATEMENT OF INVESTMENTS (UNAUDITED), CONTINUED

Number of Shares			Value
		> Finland 7.1%
	92,850	Munksjo (c)	$	1,010,840
	93,030	Munksjo		995,659
		Specialty Paper Maker
	25,836	Konecranes		752,629
		Manufacture & Service of Industrial Cranes & Port Handling Equipment
	33,751	Tikkurila		670,894
		Decorative & Industrial Paint in Scandinavia, Central & Eastern Europe
	160,990	Sponda		594,078
		Office, Retail & Logistics Properties
				4,024,100
		> Netherlands 6.8%
	32,560	Aalberts Industries		967,019
		Flow Control & Heat Treatment
	35,741	Brunel		709,057
		Temporary Specialist & Energy Staffing
	11,490	Vopak		579,828
		Operator of Petroleum & Chemical Storage Terminals
	20,005	Arcadis		550,204
		Engineering Consultants
	6,060	Gemalto		539,668
		Digital Security Solutions
	4,400	Core Labs (b)		501,776
		Oil & Gas Reservoir Consulting
				3,847,552
		> Spain 6.0%
	202,320	Distribuidora Internacional de Alimentación		1,545,061
		Discount Retailer in Spain & Latin America
	142,750	Prosegur		782,992
		Security Guards
	8,720	Viscofan		527,391
		Sausage Casings Maker
	12,520	Bolsas y Mercados Españoles		506,393
		Spanish Stock Markets
				3,361,837
		> Switzerland 4.8%
	4,480	Partners Group		1,339,280
		Private Markets Asset Management
	2,530	Geberit		843,469
		Plumbing Systems
	1,530	INFICON		522,846
		Gas Detection Instruments
				2,705,595
		> Denmark 3.7%
	14,000	William Demant Holding (a)		1,068,008
		Manufacture & Distribution of Hearing Aids & Diagnostic Equipment
	25,640	SimCorp		1,021,094
		Software for Investment Managers
				2,089,102

Number of Shares			Value
		> Norway 2.2%
	87,370	Orkla	$	687,553
		Food & Brands, Aluminum, Chemicals Conglomerate
	62,050	Atea		553,986
		Nordic IT Hardware/Software Reseller & Integrator
				1,241,539
		> Italy 1.3%
	10,540	Industria Macchine Automatiche		491,172
		Food & Drugs Packaging & Machinery
	105,433	Hera		263,764
		Northern Italian Utility
				754,936
		> Belgium 1.0%
	19,420	EVS Broadcast Equipment		562,910
		Digital Live Mobile Production Software & Systems
Europe: Total				52,572,477
Total Equities: 93.1% (Cost: $50,576,150)				52,572,477	(d)
Short-Term Investments 6.4%
	3,621,171	JPMorgan U.S. Government Money Market Fund, IM Shares (7 day yield of 0.01%)		3,621,171
Total Short-Term Investments: 6.4% (Cost: $3,621,171)				3,621,171
Securities Lending Collateral 3.2%
	1,790,781	Dreyfus Government Cash Management Fund, Institutional Shares (7 day yield of 0.01%) (e)		1,790,781
Total Securities Lending Collateral: 3.2% (Cost: $1,790,781)				1,790,781
Total Investments: 102.7% (Cost: $55,988,102)(f)				57,984,429
Obligation to Return Collateral for Securities Loaned: (3.2)%				(1,790,781	)
Cash and Other Assets Less Liabilities: 0.5%				290,425
Net Assets: 100.0%			$	56,484,073

See accompanying notes to financial statements.

> Notes to Statement of Investments

(a) Non-income producing security.

(b) All or a portion of this security was on loan at June 30, 2015. The total market value of securities on loan at June 30, 2015 was $1,540,884.

(d) On June 30, 2015, the Fund's total equity investments were denominated in currencies as follows:

Currency	Value		Percentage of Net Assets
Euro	$	22,202,800		39.3
British Pound		17,452,806		30.9
Swedish Krona		6,378,859		11.3
Other currencies less than 5% of total net assets		6,538,012		11.6
Total Equities	$	52,572,477		93.1

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

(f) At June 30, 2015, for federal income tax purposes, the cost of investments was approximately $55,988,102 and net unrealized appreciation was $1,996,327 consisting of gross unrealized appreciation of $4,973,486 and gross unrealized depreciation of $2,977,159.

Fair Value Measurements

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

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

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

The Committee is responsible for applying the Trust's Portfolio Pricing Policy and the CWAM pricing procedures (the Policies), which are approved by and subject to the oversight of the Board.

See accompanying notes to financial statements.

COLUMBIA ACORN EUROPEAN FUND^SM

STATEMENT OF INVESTMENTS (UNAUDITED), CONTINUED

> Notes to Statement of Investments

The following table summarizes the inputs used, as of June 30, 2015, in valuing the Fund's assets:

Investment Type	Quoted Prices (Level 1)		Other Significant Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)		Total
Equities
Europe	$	501,776	$	52,070,701	$	-	$	52,572,477
Total Equities		501,776		52,070,701		-		52,572,477
Total Short-Term Investments		3,621,171		-		-		3,621,171
Total Securities Lending Collateral		1,790,781		-		-		1,790,781
Total Investments	$	5,913,728	$	52,070,701	$	-	$	57,984,429

There were no transfers of financial assets between levels during the period.

See accompanying notes to financial statements.

COLUMBIA ACORN EUROPEAN FUND^SM

PORTFOLIO DIVERSIFICATION (UNAUDITED)

At June 30, 2015, the Fund's portfolio investments as a percentage of net assets were diversified as follows:

	Value		Percentage of Net Assets
> Industrial Goods & Services
Machinery	$	5,788,579		10.2
Industrial Materials & Specialty Chemicals		3,649,388		6.5
Other Industrial Services		3,600,811		6.4
Outsourcing Services		3,516,577		6.2
Conglomerates		2,847,267		5.0
Construction		1,377,181		2.5
Electrical Components		1,106,466		2.0
		21,886,269		38.8
> Information
Business Software		3,324,747		5.9
Telephone & Data Services		1,638,305		2.9
Computer Services		1,202,304		2.1
Computer Hardware & Related Equipment		1,102,578		2.0
Satellite Broadcasting & Services		1,033,442		1.8
Financial Processors		723,777		1.3
Advertising		669,373		1.2
TV Broadcasting		575,997		1.0
Instrumentation		561,411		1.0
Internet Related		554,031		1.0
		11,385,965		20.2
> Consumer Goods & Services
Retail		4,361,889		7.7
Food & Beverage		2,371,348		4.2
Casinos & Gaming		888,852		1.5
Restaurants		537,301		1.0
Consumer Goods Distribution		501,645		0.9
		8,661,035		15.3
> Finance
Insurance		1,904,251		3.4
Brokerage & Money Management		1,339,280		2.3
Financial Processors		506,393		0.9
		3,749,924		6.6
> Health Care
Medical Equipment & Devices		1,068,008		1.9
Health Care Services		962,970		1.7
Pharmaceuticals		823,254		1.4
Medical Supplies		537,260		1.0
		3,391,492		6.0
> Other Industries
Real Estate		2,152,424		3.8
Regulated Utilities		263,764		0.5
		2,416,188		4.3

	Value			Percentage of Net Assets
> Energy & Minerals
Oil Refining, Marketing & Distribution	$	579,828			1.0
Mining		501,776			0.9
		1,081,604			1.9
Total Equities:		52,572,477			93.1
Short-Term Investments:		3,621,171			6.4
Securities Lending Collateral:		1,790,781			3.2
Total Investments:		57,984,429			102.7
Obligation to Return Collateral for Securities Loaned:		(1,790,781	)		(3.2	)
Cash and Other Assets Less Liabilities:		290,425			0.5
Net Assets:	$	56,484,073			100.0

See accompanying notes to financial statements.

COLUMBIA ACORN FAMILY OF FUNDS

STATEMENTS OF ASSETS AND LIABILITIES (UNAUDITED)

June 30, 2015	Columbia Acorn® Fund			Columbia Acorn International®			Columbia Acorn USA®			Columbia Acorn International Select^SM
Assets:
Unaffiliated investments, at cost	$	5,884,502,588		$	6,529,514,535		$	833,925,047		$	209,812,793
Affiliated investments, at cost		1,156,736,525			113,439,966			—			—
Unaffiliated investments, at value (including securities on loan: Columbia Acorn Fund $205,238,253; Columbia Acorn International $178,244,535; Columbia Acorn USA $53,095,035; Columbia Acorn International Select $7,925,539; Columbia Acorn Select $13,779,499; Columbia Thermostat Fund $—; Columbia Acorn Emerging Markets Fund $2,610,061; Columbia Acorn European Fund $1,540,884)	$	10,161,532,903		$	7,924,906,545		$	1,367,318,287		$	232,251,748
Affiliated investments, at value		1,926,769,533			105,542,951			—			—
Cash		—			22,910			—			—
Foreign currency (cost: Columbia Acorn Fund $—; Columbia Acorn International $1,962,772; Columbia Acorn USA $—; Columbia Acorn International Select $109; Columbia Acorn Select $—; Columbia Thermostat Fund $—; Columbia Acorn Emerging Markets Fund $133,903; Columbia Acorn European Fund $—)		—			1,963,010			—			109
Receivable for:
Investments sold		22,561,608			74,143,778			2,685,183			—
Fund shares sold		13,527,673			22,195,532			1,644,367			47,983
Dividends		5,422,840			11,796,885			448,579			142,284
Securities lending income		163,252			111,073			42,863			9,658
Foreign tax reclaims		58,756			6,327,061			—			245,012
Expense reimbursement due from Investment Manager		—			1,115			—			1
Trustees' deferred compensation plan		3,732,536			1,231,519			321,717			—
Prepaid expenses		235,962			212,075			26,965			9,701
Other assets		103,205			9,030			12,324			6,107
Total Assets		12,134,108,268			8,148,463,484			1,372,500,285			232,712,603
Liabilities:
Payable to custodian bank		—			—			—			—
Collateral on securities loaned		205,638,386			186,393,214			53,302,525			8,381,123
Unrealized depreciation on forward foreign currency exchange contracts		—			—			—			237,682
Payable for:
Investments purchased		23,067,085			33,282,970			5,356,578			—
Fund shares redeemed		60,749,497			23,014,517			1,470,847			501,728
Investment advisory fee		209,364			163,116			30,940			5,766
Administration fee		13,026			8,680			1,436			247
12b-1 Service and Distribution fees		34,562			9,583			1,907			507
Reports to shareholders		644,720			413,610			69,025			25,541
Transfer agent fees		2,166,867			930,150			330,219			22,034
Trustees' fees		31,863			16,478			2,600			58,523
Custody fees		75,687			556,460			5,788			18,269
Professional fee		128,228			94,243			27,857			24,716
Chief compliance officer expenses		17,885			4,396			1,205			275
Deferred foreign capital gains tax payable		—			—			—			—
Trustees' deferred compensation plan		3,732,536			1,231,519			321,717			—
Other liabilities		—			2,558			1,501			4,609
Total Liabilities		296,509,706			246,121,494			60,924,145			9,281,020
Net Assets	$	11,837,598,562		$	7,902,341,990		$	1,311,576,140		$	223,431,583
Composition of Net Assets:
Paid-in capital	$	3,870,452,801		$	6,126,660,558		$	564,952,456		$	209,031,074
Undistributed (Overdistributed) net investment income (loss)		(14,257,690	)		(32,804,029	)		(2,316,494	)		(5,561,522	)
Accumulated net realized gain (loss)		2,934,350,221			421,421,418			215,546,938			(2,232,353	)
Net unrealized appreciation (depreciation) on:
Unaffiliated investments		4,277,030,315			1,395,392,010			533,393,240			22,438,955
Affiliated investments		770,033,008			(7,897,015	)		—			—
Foreign currency translations		(10,093	)		(430,952	)		—			(6,889	)
Forward foreign currency exchange contracts		—			—			—			(237,682	)
Foreign capital gains tax		—			—			—			—
Net Assets	$	11,837,598,562		$	7,902,341,990		$	1,311,576,140		$	223,431,583
Net asset value per share – Class A (a)	$	30.63		$	43.41		$	30.38		$	22.76
(Net assets/shares)	($	2,201,584,812/ 71,874,546)		($	964,828,350/ 22,226,587)		($	136,711,178/ 4,500,769)		($	43,965,056/ 1,931,638)
Maximum offering price per share – Class A (b)	$	32.50		$	46.06		$	32.23		$	24.15
(Net asset value per share/front-end sales charge)	($	30.63/ 0.9425	)	($	43.41/ 0.9425	)	($	30.38/ 0.9425	)	($	22.76/ 0.9425	)
Net asset value and offering price per share – Class B (a)	$	26.51		$	41.87		$	26.07		$	21.37
(Net assets/shares)	($	3,569,962/ 134,688	)	($	3,915,301/ 93,518	)	($	129,868/ 4,981	)	($	136,004/ 6,363	)
Net asset value and offering price per share – Class C (a)	$	25.87		$	41.69		$	25.84		$	21.23
(Net assets/shares)	($	712,925,650/ 27,553,005)		($	104,159,630/ 2,498,144)		($	35,239,436/ 1,363,848)		($	7,250,111/ 341,543)
Net asset value and offering price per share – Class I (c)	$	32.53		$	43.57		$	32.65	(d)	$	23.06	(d)
(Net assets/shares)	($	29,576,462/ 909,167)		($	59,073,900/ 1,355,734)		($	2,292/ 70	)	($	2,125/ 92	)
Net asset value and offering price per share – Class R (c)	$	—		$	43.32		$	—		$	—
(Net assets/shares)	($	—/ —	)	($	4,989,417/ 115,180	)	($	—/ —	)	($	—/ —	)
Net asset value and offering price per share – Class R4 (c)	$	33.02		$	43.80		$	33.17		$	23.22
(Net assets/shares)	($	200,539,115/ 6,073,263)		($	500,423,263/ 11,423,910)		($	12,550,745/ 378,329)		($	1,080,091/ 46,510)
Net asset value and offering price per share – Class R5 (c)	$	33.07		$	43.50		$	33.20		$	23.21
(Net assets/shares)	($	198,784,398/ 6,010,226)		($	410,552,304/ 9,437,135)		($	35,962,075/ 1,083,095)		($	3,484,879/ 150,154)
Net asset value and offering price per share – Class Y (c)	$	33.15		$	43.85		$	33.30		$	23.20
(Net assets/shares)	($	204,378,360/ 6,165,101)		($	300,536,288/ 6,853,996)		($	36,734,493/ 1,103,115)		($	10,763,082/ 463,850)
Net asset value and offering price per share – Class Z (c)	$	32.44		$	43.52		$	32.45		$	23.07
(Net assets/shares)	($	8,286,239,803/ 255,433,395)		($	5,553,863,537/ 127,618,393)		($	1,054,246,053/ 32,485,476)		($	156,750,235/ 6,795,995)

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

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

(d) Net asset value per share rounds to this amount due to fractional shares outstanding.

See accompanying notes to financial statements.

June 30, 2015	Columbia Acorn Select^SM			Columbia Thermostat Fund^SM			Columbia Acorn Emerging Markets Fund^SM			Columbia Acorn European Fund^SM
Assets:
Unaffiliated investments, at cost	$	457,344,450		$	5,691,503		$	421,007,801		$	55,988,102
Affiliated investments, at cost		17,688,954			1,146,086,714			—			—
Unaffiliated investments, at value (including securities on loan: Columbia Acorn Fund $205,238,253; Columbia Acorn International $178,244,535; Columbia Acorn USA $53,095,035; Columbia Acorn International Select $7,925,539; Columbia Acorn Select $13,779,499; Columbia Thermostat Fund $—; Columbia Acorn Emerging Markets Fund $2,610,061; Columbia Acorn European Fund $1,540,884)	$	609,324,216		$	5,691,503		$	420,915,008		$	57,984,429
Affiliated investments, at value		2,019,797			1,179,928,856			—			—
Cash		—			—			—			—
Foreign currency (cost: Columbia Acorn Fund $—; Columbia Acorn International $1,962,772; Columbia Acorn USA $—; Columbia Acorn International Select $109; Columbia Acorn Select $—; Columbia Thermostat Fund $—; Columbia Acorn Emerging Markets Fund $133,903; Columbia Acorn European Fund $—)		—			—			133,903			—
Receivable for:
Investments sold		4,358,956			63,059,408			13,335			—
Fund shares sold		6,195,956			1,531,557			555,580			408,776
Dividends		355,508			1,906,627			989,327			88,822
Securities lending income		4,380			—			2,560			2,456
Foreign tax reclaims		—			—			11,676			50,979
Expense reimbursement due from Investment Manager		4			733			—			299
Trustees' deferred compensation plan		332,407			—			—			—
Prepaid expenses		22,069			32,920			21,272			1,943
Other assets		8,211			21,385			11,756			19,629
Total Assets		622,621,504			1,252,172,989			422,654,417			58,557,333
Liabilities:
Payable to custodian bank		—			—			—			10
Collateral on securities loaned		14,060,046			—			2,703,540			1,790,781
Unrealized depreciation on forward foreign currency exchange contracts		—			—			—			—
Payable for:
Investments purchased		2,388,210			64,732,398			2,034,748			139,818
Fund shares redeemed		910,250			8,872,800			610,917			92,473
Investment advisory fee		10,639			3,248			11,970			1,874
Administration fee		658			1,306			454			63
12b-1 Service and Distribution fees		2,882			13,434			1,881			422
Reports to shareholders		59,465			68,675			46,603			12,072
Transfer agent fees		70,191			76,766			46,950			3,447
Trustees' fees		1,177			76,395			18,624			2,233
Custody fees		4,411			634			87,583			6,570
Professional fee		26,266			25,009			16,531			23,465
Chief compliance officer expenses		77			774			386			29
Deferred foreign capital gains tax payable		—			—			200,892			—
Trustees' deferred compensation plan		332,407			—			—			—
Other liabilities		5,981			—			1,293			3
Total Liabilities		17,872,660			73,871,439			5,782,372			2,073,260
Net Assets	$	604,748,844		$	1,178,301,550		$	416,872,045		$	56,484,073
Composition of Net Assets:
Paid-in capital	$	361,957,932		$	1,133,261,458		$	430,309,656		$	56,641,648
Undistributed (Overdistributed) net investment income (loss)		(1,364,620	)		9,640,304			186,119			438,439
Accumulated net realized gain (loss)		107,844,886			1,557,646			(13,334,597	)		(2,590,825	)
Net unrealized appreciation (depreciation) on:
Unaffiliated investments		151,979,766			—			(92,793	)		1,996,327
Affiliated investments		(15,669,157	)		33,842,142			—			—
Foreign currency translations		37			—			4,552			(1,516	)
Forward foreign currency exchange contracts		—			—			—			—
Foreign capital gains tax		—			—			(200,892	)		—
Net Assets	$	604,748,844		$	1,178,301,550		$	416,872,045		$	56,484,073
Net asset value per share – Class A (a)	$	20.52		$	14.72		$	12.34		$	15.23
(Net assets/shares)	($	244,592,468/ 11,920,327)		($	427,618,435/ 29,051,227)		($	138,930,231/ 11,260,046)		($	34,321,233/ 2,253,306)
Maximum offering price per share – Class A (b)	$	21.77		$	15.62		$	13.09		$	16.16
(Net asset value per share/front-end sales charge)	($	20.52/ 0.9425	)	($	14.72/ 0.9425	)	($	12.34/ 0.9425	)	($	15.23/ 0.9425	)
Net asset value and offering price per share – Class B (a)	$	17.26		$	14.79		$	—		$	—
(Net assets/shares)	($	533,043/ 30,882	)	($	936,608/ 63,321	)	($	—/ —	)	($	—/ —	)
Net asset value and offering price per share – Class C (a)	$	16.91		$	14.77		$	12.23		$	15.05
(Net assets/shares)	($	43,848,238/ 2,592,709)		($	380,771,475/ 25,786,150)		($	34,754,361/ 2,842,556)		($	6,711,435/ 445,849)
Net asset value and offering price per share – Class I (c)	$	22.00		$	—		$	12.39	(d)	$	15.24	(d)
(Net assets/shares)	($	29,504,706/ 1,341,340)		($	—/—	)	($	2,464/ 199	)	($	2,570/ 169	)
Net asset value and offering price per share – Class R (c)	$	—		$	—		$	—		$	—
(Net assets/shares)	($	—/ —	)	($	—/ —	)	($	—/ —	)	($	—/ —	)
Net asset value and offering price per share – Class R4 (c)	$	22.37		$	14.62		$	12.46		$	15.31
(Net assets/shares)	($	1,282,018/ 57,321)		($	21,958,860/ 1,502,364)		($	13,811,663/ 1,108,467)		($	596,718/ 38,966)
Net asset value and offering price per share – Class R5 (c)	$	22.41		$	14.63		$	12.45		$	15.39
(Net assets/shares)	($	2,301,531/ 102,717)		($	4,748,730/ 324,569)		($	18,725,068/ 1,503,468)		($	1,857,724/ 120,724)
Net asset value and offering price per share – Class Y (c)	$	22.50		$	14.62		$	12.35	(d)	$	—
(Net assets/shares)	($	4,134,662/ 183,748)		(	$341,764/ 23,380)		($	2,341/ 190	)	($	—/—	)
Net asset value and offering price per share – Class Z (c)	$	21.87		$	14.55		$	12.38		$	15.25
(Net assets/shares)	($	278,552,178/ 12,734,723)		($	341,925,678/ 23,504,812)		($	210,645,917/ 17,019,818)		($	12,994,393/ 852,156)

See accompanying notes to financial statements.

COLUMBIA ACORN FAMILY OF FUNDS

STATEMENTS OF OPERATIONS (UNAUDITED) FOR THE SIX MONTHS ENDED JUNE 30, 2015

	Columbia Acorn® Fund			Columbia Acorn International®			Columbia Acorn USA®			Columbia Acorn International Select^SM
Investment Income:
Dividends	$	37,435,400		$	103,560,690		$	5,368,854		$	3,256,827
Dividends from affiliates		12,817,213			4,360,275			—			—
Dividends from affiliated investment company shares		—			—			—			—
Interest		1,816			1,103,748			—			414,370
Income from securities lending – net		2,162,958			1,056,847			256,375			52,206
		52,417,387			110,081,560			5,625,229			3,723,403
Foreign taxes withheld		(345,122	)		(10,747,369	)		(7,755	)		(260,399	)
Total Investment Income		52,072,265			99,334,191			5,617,474			3,463,004
Expenses:
Investment advisory fee		44,604,960			29,994,326			5,819,239			1,146,008
Administration fee		2,717,589			1,559,011			263,888			47,860
12b-1 Service and Distribution fees:
Class A		3,045,470			1,213,818			174,773			62,187
Class B		19,548			19,736			708			930
Class C		3,704,961			527,236			179,834			38,798
Class R		—			12,333			—			—
Transfer agency fees:
Class A		1,431,185			797,171			94,207			35,303
Class B		11,104			13,155			775			528
Class C		267,824			72,767			10,851			6,247
Class R		—			5,933			—			—
Class R4		168,432			441,668			6,968			615
Class R5		62,633			104,276			9,713			833
Class Z		4,115,768			2,557,255			738,242			74,979
Trustees' fees		462,467			245,332			42,232			11,662
Custody fees		91,961			769,454			11,891			24,813
Registration and blue sky fees		78,070			104,115			49,165			46,731
Reports to shareholders		825,027			770,972			97,035			46,060
Audit fees		47,976			51,477			21,344			24,908
Legal fees		518,023			307,210			44,910			8,877
Chief compliance officer expenses		258,240			141,370			24,303			4,414
Other expenses		282,953			259,067			31,775			13,186
Total Expenses		62,714,191			39,967,682			7,621,853			1,594,939
Less reimbursement of expenses by Investment Manager and its affiliates		—			(205,545	)		—			(116	)
Less advisory fee waiver		—			—			—			—
Net Expenses		62,714,191			39,762,137			7,621,853			1,594,823
Net Investment Income (Loss)		(10,641,926	)		59,572,054			(2,004,379	)		1,868,181
Net Realized and Unrealized Gain (Loss) on Investments:
Net realized gain (loss) on:
Unaffiliated investments		2,536,315,696			468,170,226			216,222,274			6,347,553
Affiliated investments		406,561,058			(175,391	)		—			—
Distributions from affiliated investment company shares		—			—			—			—
Foreign currency translations		(197,976	)		(2,345,642	)		—			(86,725	)
Forward foreign currency exchange contracts		—			—			—			291,763
Futures contracts		2,900,917			—			—			—
Net realized gain		2,945,579,695			465,649,193			216,222,274			6,552,591
Net change in net unrealized appreciation (depreciation) on:
Unaffiliated investments		(1,568,742,526	)		(129,136,187	)		(117,673,779	)		1,640,686
Affiliated investments		(474,699,646	)		(1,045,560	)		—			—
Foreign currency translations		1,107			192,366			—			17,920
Forward foreign currency exchange contracts		—			—			—			(140,501	)
Foreign capital gains tax		1,217,682			771,879			—			—
Net change in unrealized appreciation (depreciation)		(2,042,223,383	)		(129,217,502	)		(117,673,779	)		1,518,105
Net realized and unrealized gain (loss)		903,356,312			336,431,691			98,548,495			8,070,696
Net Increase (Decrease) in Net Assets from Operations	$	892,714,386		$	396,003,745		$	96,544,116		$	9,938,877

See accompanying notes to financial statements.

	Columbia Acorn Select^SM			Columbia Thermostat Fund^SM			Columbia Acorn Emerging Markets Fund^SM			Columbia Acorn European Fund^SM
Investment Income:
Dividends	$	2,635,490		$	279		$	6,449,859		$	955,274
Dividends from affiliates		—			—			—			—
Dividends from affiliated investment company shares		—			13,801,311			—			—
Interest		—			—			55,264			—
Income from securities lending – net		20,213			—			16,465			12,745
		2,655,703			13,801,590			6,521,588			968,019
Foreign taxes withheld		(7,178	)		—			(355,763	)		(115,455	)
Total Investment Income		2,648,525			13,801,590			6,165,825			852,564
Expenses:
Investment advisory fee		2,659,877			612,624			2,396,766			266,531
Administration fee		122,858			240,525			89,223			8,811
12b-1 Service and Distribution fees:
Class A		316,212			551,831			189,178			32,738
Class B		2,810			4,114			—			—
Class C		228,674			1,969,943			195,080			28,956
Class R		—			—			—			—
Transfer agency fees:
Class A		151,533			165,948			91,432			13,999
Class B		2,665			1,318			—			—
Class C		22,690			142,447			24,351			3,483
Class R		—			—			—			—
Class R4		886			8,027			5,715			538
Class R5		2,256			1,101			4,924			428
Class Z		140,524			108,791			132,189			4,474
Trustees' fees		20,240			37,903			17,520			1,788
Custody fees		7,347			1,520			121,680			9,541
Registration and blue sky fees		49,470			63,637			49,755			37,717
Reports to shareholders		95,274			125,003			72,758			17,590
Audit fees		21,344			11,686			34,598			20,832
Legal fees		21,220			49,279			15,906			1,259
Chief compliance officer expenses		10,855			22,512			8,279			668
Other expenses		19,325			26,901			44,195			9,181
Total Expenses		3,896,060			4,145,110			3,493,549			458,534
Less reimbursement of expenses by Investment Manager and its affiliates		(1,016	)		(100,577	)		—			(60,916	)
Less advisory fee waiver		(207,859	)		—			—			—
Net Expenses		3,687,185			4,044,533			3,493,549			397,618
Net Investment Income (Loss)		(1,038,660	)		9,757,057			2,672,276			454,946
Net Realized and Unrealized Gain (Loss) on Investments:
Net realized gain (loss) on:
Unaffiliated investments		122,757,395			—			2,178,549			130,811
Affiliated investments		(14,793,039	)		746,952			—			—
Distributions from affiliated investment company shares		—			4,641,797			—			—
Foreign currency translations		(3,634	)		—			(292,856	)		(958	)
Forward foreign currency exchange contracts		—			—			—			—
Futures contracts		—			—			—			—
Net realized gain		107,960,722			5,388,749			1,885,693			129,853
Net change in net unrealized appreciation (depreciation) on:
Unaffiliated investments		(75,415,098	)		—			(17,639,889	)		1,568,374
Affiliated investments		5,306,853			(2,463,415	)		—			—
Foreign currency translations		37			—			14,903			1,705
Forward foreign currency exchange contracts		—			—			—			—
Foreign capital gains tax		—			—			469,883			—
Net change in unrealized appreciation (depreciation)		(70,108,208	)		(2,463,415	)		(17,155,103	)		1,570,079
Net realized and unrealized gain (loss)		37,852,514			2,925,334			(15,269,410	)		1,699,932
Net Increase (Decrease) in Net Assets from Operations	$	36,813,854		$	12,682,391		$	(12,597,134	)	$	2,154,878

See accompanying notes to financial statements.

COLUMBIA ACORN FAMILY OF FUNDS

STATEMENTS OF CHANGES IN NET ASSETS

	Columbia Acorn® Fund						Columbia Acorn International®						Columbia Acorn USA®						Columbia Acorn International Select^SM
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,			(Unaudited) Six months ended June 30,			Year ended December 31,
	2015			2014			2015			2014			2015			2014			2015			2014
Operations:
Net investment income (loss)	$	(10,641,926	)	$	(4,904,097	)	$	59,572,054		$	95,286,191		$	(2,004,379	)	$	(6,182,121	)	$	1,868,181		$	4,277,133
Net realized gain (loss) on investments, foreign currency translations, forward foreign currency exchange contracts, futures contracts and foreign capital gains tax		2,539,018,637			2,436,637,992			465,824,584			480,895,123			216,222,274			257,777,850			6,552,591			26,265,551
Net realized gain (loss) on affiliated investments and distributions from affiliated investment company shares		406,561,058			821,706,250			(175,391	)		(17,504,372	)		—			—			—			—
Net change in net unrealized appreciation (depreciation) on investments, foreign currency translations, forward foreign currency exchange contracts, futures contracts, options and foreign capital gains tax		(1,567,523,737	)		(2,178,954,324	)		(128,171,942	)		(908,876,254	)		(117,673,779	)		(207,204,706	)		1,518,105			(51,145,788	)
Net change in net unrealized appreciation (depreciation) on affiliated investments, affiliated options and affiliated investment company shares		(474,699,646	)		(983,776,070	)		(1,045,560	)		(10,747,516	)		—			—			—			—
Net Increase (Decrease) in Net Assets from Operations		892,714,386			90,709,751			396,003,745			(360,946,828	)		96,544,116			44,391,023			9,938,877			(20,603,104	)
Distributions to Shareholders From:
Net investment income – Class A		—			—			—			(11,982,984	)		—			—			(195,302	)		(224,613	)
Net realized gain – Class A		(116,633,259	)		(486,737,575	)		(8,544,526	)		(51,297,757	)		(3,745,127	)		(28,022,455	)		—			(6,609,718	)
Net investment income – Class B		—			—			—			(33,111	)		—			—			(116	)		—
Net realized gain – Class B		(230,292	)		(1,499,818	)		(39,614	)		(404,076	)		(4,529	)		(50,293	)		—			(51,627	)
Net investment income – Class C		—			—			—			(500,190	)		—			—			—			—
Net realized gain – Class C		(43,650,093	)		(148,638,681	)		(961,655	)		(5,765,804	)		(1,139,915	)		(7,386,824	)		—			(1,052,637	)
Net investment income – Class I		—			—			—			(432,624	)		—			—			(9	)		(19	)
Net realized gain – Class I		(1,148,694	)		(3,521,541	)		(403,320	)		(1,776,863	)		(59	)		(424	)		—			(267	)
Net investment income – Class R		—			—			—			(45,702	)		—			—			—			—
Net realized gain – Class R		—			—			(42,993	)		(308,877	)		—			—			—			—
Net investment income – Class R4		—			—			—			(5,947,002	)		—			—			(4,558	)		(7,289	)
Net realized gain – Class R4		(9,648,616	)		(21,919,022	)		(4,288,552	)		(21,064,501	)		(308,779	)		(1,294,173	)		—			(123,308	)
Net investment income – Class R5		—			—			—			(6,469,747	)		—			—			(14,655	)		(19,269	)
Net realized gain – Class R5		(9,334,102	)		(83,114,711	)		(3,698,560	)		(20,627,952	)		(1,044,575	)		(5,923,118	)		—			(294,842	)
Net investment income – Class Y		—			—			—			(3,631,416	)		—			—			(45,324	)		(94,386	)
Net realized gain – Class Y		(9,941,189	)		(70,995,899	)		(2,167,824	)		(11,216,211	)		(900,699	)		(5,748,134	)		—			(1,353,410	)
Net investment income – Class Z		—			—			—			(88,209,132	)		—			—			(677,019	)		(1,436,806	)
Net realized gain – Class Z		(417,947,664	)		(1,866,279,508	)		(49,616,630	)		(300,186,783	)		(26,752,653	)		(197,817,289	)		—			(23,156,256	)
Total Distributions to Shareholders		(608,533,909	)		(2,682,706,755	)		(69,763,674	)		(529,900,732	)		(33,896,336	)		(246,242,710	)		(936,983	)		(34,424,447	)
Share Transactions:
Subscriptions – Class A		93,074,864			387,297,277			88,084,398			235,302,578			6,628,133			25,880,527			4,747,419			17,687,288
Distributions reinvested – Class A		108,977,754			458,120,888			8,303,010			61,324,199			3,534,801			25,490,248			189,769			6,671,741
Redemptions – Class A		(732,743,039	)		(1,539,008,962	)		(116,920,214	)		(328,383,569	)		(27,438,727	)		(81,566,768	)		(16,257,050	)		(33,811,493	)
Net Increase (Decrease) – Class A		(530,690,421	)		(693,590,797	)		(20,532,806	)		(31,756,792	)		(17,275,793	)		(30,195,993	)		(11,319,862	)		(9,452,464	)
Distributions reinvested – Class B		219,826			1,459,028			38,735			428,823			4,509			50,412			115			51,402
Redemptions – Class B		(3,939,069	)		(11,842,669	)		(2,900,267	)		(6,307,820	)		(117,003	)		(333,713	)		(231,008	)		(493,902	)
Net Increase (Decrease) – Class B		(3,719,243	)		(10,383,641	)		(2,861,532	)		(5,878,997	)		(112,494	)		(283,301	)		(230,893	)		(442,500	)
Subscriptions – Class C		19,260,660			69,519,166			6,306,990			20,327,395			876,651			2,990,564			414,983			1,124,408
Distributions reinvested – Class C		36,898,128			124,358,458			861,856			5,543,900			1,076,963			7,016,021			—			965,830
Redemptions – Class C		(120,261,072	)		(204,072,123	)		(10,534,195	)		(20,718,133	)		(4,445,839	)		(7,454,664	)		(1,493,115	)		(2,579,871	)
Net Increase (Decrease) – Class C		(64,102,284	)		(10,194,499	)		(3,365,349	)		5,153,162			(2,492,225	)		2,551,921			(1,078,132	)		(489,633	)
Subscriptions – Class I		12,665,465			82,894,450			37,365,938			106,632,159			—			—			—			—
Distributions reinvested – Class I		1,148,584			3,521,166			403,299			2,209,323			—			—			—			—
Redemptions – Class I		(12,470,677	)		(79,941,110	)		(18,043,810	)		(98,916,651	)		—			(1,200	)		—			(100	)
Net Increase (Decrease) – Class I		1,343,372			6,474,506			19,725,427			9,924,831			—			(1,200	)		—			(100	)
Subscriptions – Class R		—			—			733,516			3,552,904			—			—			—			—
Distributions reinvested – Class R		—			—			39,018			324,934			—			—			—			—
Redemptions – Class R		—			—			(1,525,848	)		(3,574,734	)		—			—			—			—
Net Increase (Decrease) – Class R		—			—			(753,314	)		303,104			—			—			—			—

(a) Class R4 shares reflect activity for the period from June 25, 2014 (commencement of operations) through December 31, 2014.

See accompanying notes to financial statements.

	Columbia Acorn Select^SM						Columbia Thermostat Fund^SM						Columbia Acorn Emerging Markets Fund^SM						Columbia Acorn European Fund^SM
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,			(Unaudited) Six months ended June 30,			Year ended December 31,
	2015			2014			2015			2014			2015			2014			2015			2014 (a)
Operations:
Net investment income (loss)	$	(1,038,660	)	$	(3,672,062	)	$	9,757,057		$	22,277,306		$	2,672,276		$	2,430,118		$	454,946		$	404,894
Net realized gain (loss) on investments, foreign currency translations, forward foreign currency exchange contracts, futures contracts and foreign capital gains tax		122,753,761			158,802,272			—			35			1,885,693			(9,229,406	)		129,853			(2,712,928	)
Net realized gain (loss) on affiliated investments and distributions from affiliated investment company shares		(14,793,039	)		(5,568,755	)		5,388,749			38,178,162			—			—			—			—
Net change in net unrealized appreciation (depreciation) on investments, foreign currency translations, forward foreign currency exchange contracts, futures contracts, options and foreign capital gains tax		(75,415,061	)		(133,989,051	)		—			—			(17,155,103	)		(14,640,892	)		1,570,079			(3,116,709	)
Net change in net unrealized appreciation (depreciation) on affiliated investments, affiliated options and affiliated investment company shares		5,306,853			854,842			(2,463,415	)		4,982,086			—			—			—			—
Net Increase (Decrease) in Net Assets from Operations		36,813,854			16,427,246			12,682,391			65,437,589			(12,597,134	)		(21,440,180	)		2,154,878			(5,424,743	)
Distributions to Shareholders From:
Net investment income – Class A		—			—			(651,664	)		(8,397,874	)		—			(1,094,797	)		(144,797	)		(84,996	)
Net realized gain – Class A		(19,933,244	)		(56,636,824	)		(8,171,921	)		(6,398,591	)		—			—			—			(169,484	)
Net investment income – Class B		—			—			(1,472	)		(17,083	)		—			—			—			—
Net realized gain – Class B		(54,843	)		(297,506	)		(18,462	)		(18,454	)		—			—			—			—
Net investment income – Class C		—			—			(571,885	)		(4,546,957	)		—			—			—			—
Net realized gain – Class C		(4,321,966	)		(12,212,259	)		(7,171,478	)		(5,614,280	)		—			—			—			(21,837	)
Net investment income – Class I		—			—			—			—			—			(25	)		(12	)		(17	)
Net realized gain – Class I		(1,777,897	)		(3,400,475	)		—			—			—			—			—			(13	)
Net investment income – Class R		—			—			—			—			—			—			—			—
Net realized gain – Class R		—			—			—			—			—			—			—			—
Net investment income – Class R4		—			—			(33,548	)		(496,795	)		—			(139,747	)		(5,491	)		(1,628	)
Net realized gain – Class R4		(97,950	)		(246,466	)		(420,695	)		(305,871	)		—			—			—			—
Net investment income – Class R5		—			—			(6,981	)		(65,599	)		—			(184,675	)		(8,163	)		(11,230	)
Net realized gain – Class R5		(168,761	)		(2,042,106	)		(87,538	)		(42,379	)		—			—			—			(14,316	)
Net investment income – Class Y		—			—			(510	)		(8,730	)		—			(23	)		—			—
Net realized gain – Class Y		(308,593	)		(715,032	)		(6,396	)		(5,549	)		—			—			—			—
Net investment income – Class Z		—			—			(525,890	)		(8,020,198	)		—			(2,086,821	)		(57,214	)		(58,745	)
Net realized gain – Class Z		(21,865,469	)		(67,822,345	)		(6,594,711	)		(5,142,454	)		—			—			—			(81,656	)
Total Distributions to Shareholders		(48,528,723	)		(143,373,013	)		(24,263,151	)		(39,080,814	)		—			(3,506,088	)		(215,677	)		(443,922	)
Share Transactions:
Subscriptions – Class A		8,193,734			23,903,410			45,853,873			109,228,793			6,883,085			111,765,309			15,911,293			30,709,434
Distributions reinvested – Class A		18,677,112			52,931,442			7,892,484			13,288,881			—			1,088,373			142,046			251,848
Redemptions – Class A		(41,337,076	)		(94,474,957	)		(72,357,439	)		(196,252,756	)		(24,763,642	)		(122,334,919	)		(3,926,616	)		(25,970,474	)
Net Increase (Decrease) – Class A		(14,466,230	)		(17,640,105	)		(18,611,082	)		(73,735,082	)		(17,880,557	)		(9,481,237	)		12,126,723			4,990,808
Distributions reinvested – Class B		58,413			295,790			19,596			35,043			—			—			—			—
Redemptions – Class B		(525,387	)		(1,910,917	)		(304,881	)		(1,111,595	)		—			—			—			—
Net Increase (Decrease) – Class B		(466,974	)		(1,615,127	)		(285,285	)		(1,076,552	)		—			—			—			—
Subscriptions – Class C		1,010,251			3,943,141			26,702,268			71,129,998			977,118			16,317,984			1,920,560			5,134,061
Distributions reinvested – Class C		3,593,300			10,065,907			5,964,048			7,780,938			—			—			—			21,837
Redemptions – Class C		(7,507,276	)		(15,355,912	)		(51,531,364	)		(113,101,789	)		(6,234,688	)		(5,604,206	)		(604,204	)		(974,284	)
Net Increase (Decrease) – Class C		(2,903,725	)		(1,346,864	)		(18,865,048	)		(34,190,853	)		(5,257,570	)		10,713,778			1,316,356			4,181,614
Subscriptions – Class I		18,384,816			54,126,443			—			—			—			—			—			—
Distributions reinvested – Class I		1,777,731			3,400,003			—			—			—			24			12			29
Redemptions – Class I		(8,606,952	)		(52,140,680	)		—			—			—			(4,200	)		—			(5,500	)
Net Increase (Decrease) – Class I		11,555,595			5,385,766			—			—			—			(4,176	)		12			(5,471	)
Subscriptions – Class R		—			—			—			—			—			—			—			—
Distributions reinvested – Class R		—			—			—			—			—			—			—			—
Redemptions – Class R		—			—			—			—			—			—			—			—
Net Increase (Decrease) – Class R		—			—			—			—			—			—			—			—

See accompanying notes to financial statements.

COLUMBIA ACORN FAMILY OF FUNDS

STATEMENTS OF CHANGES IN NET ASSETS, CONTINUED

	Columbia Acorn® Fund						Columbia Acorn International®						Columbia Acorn USA®						Columbia Acorn International Select^SM
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,			(Unaudited) Six months ended June 30,			Year ended December 31,
	2015			2014			2015			2014			2015			2014			2015			2014
Subscriptions – Class R4		26,909,090			207,170,623			88,752,391			175,589,777			5,867,334			2,470,102			206,979			1,034,431
Distributions reinvested – Class R4		9,466,765			21,432,710			4,274,668			26,888,828			308,779			1,284,629			4,548			130,285
Redemptions – Class R4		(91,625,255	)		(32,595,900	)		(35,154,540	)		(86,239,207	)		(2,023,855	)		(1,252,295	)		(138,931	)		(342,802	)
Net Increase (Decrease) – Class R4		(55,249,400	)		196,007,433			57,872,519			116,239,398			4,152,258			2,502,436			72,596			821,914
Subscriptions – Class R5		33,894,346			195,425,964			59,817,513			247,362,038			4,751,339			37,680,269			1,365,563			3,308,092
Distributions reinvested – Class R5		9,316,968			82,145,922			3,667,913			27,089,438			1,044,517			5,922,697			14,647			313,832
Redemptions – Class R5		(305,121,170	)		(237,599,243	)		(67,481,458	)		(105,520,799	)		(8,301,534	)		(8,503,850	)		(594,870	)		(1,308,702	)
Net Increase (Decrease) – Class R5		(261,909,856	)		39,972,643			(3,996,032	)		168,930,677			(2,505,678	)		35,099,116			785,340			2,313,222
Subscriptions – Class Y		16,187,530			199,351,710			78,821,805			103,024,265			1,359,915			36,144,225			4,567,512			2,689,199
Distributions reinvested – Class Y		9,941,189			70,995,899			2,167,824			14,847,627			900,640			5,747,713			45,315			1,447,516
Redemptions – Class Y		(206,239,197	)		(1,053,713,427	)		(14,205,570	)		(21,611,148	)		(2,723,131	)		(48,745,200	)		(6,110,931	)		(3,306,180	)
Net Increase (Decrease) – Class Y		(180,110,478	)		(783,365,818	)		66,784,059			96,260,744			(462,576	)		(6,853,262	)		(1,498,104	)		830,535
Subscriptions – Class Z		259,804,464			982,362,041			319,142,620			856,537,476			66,614,074			102,940,940			7,097,551			43,516,847
Distributions reinvested – Class Z		353,829,315			1,619,840,849			37,832,464			294,475,850			23,540,112			173,222,058			424,872			14,556,758
Redemptions – Class Z		(3,900,353,409	)		(4,171,520,886	)		(627,224,272	)		(1,213,184,358	)		(219,745,605	)		(480,201,144	)		(32,743,379	)		(99,596,462	)
Net Increase (Decrease) – Class Z		(3,286,719,630	)		(1,569,317,996	)		(270,249,188	)		(62,171,032	)		(129,591,419	)		(204,038,146	)		(25,220,956	)		(41,522,857	)
Net Increase (Decrease) from Share Transactions		(4,381,157,940	)		(2,824,398,169	)		(157,376,216	)		297,005,095			(148,287,927	)		(201,218,429	)		(38,490,011	)		(47,941,883	)
Total Increase (Decrease) in Net Assets		(4,096,977,463	)		(5,416,395,173	)		168,863,855			(593,842,465	)		(85,640,147	)		(403,070,116	)		(29,488,117	)		(102,969,434	)
Net Assets:
Beginning of period		15,934,576,025			21,350,971,198			7,733,478,135			8,327,320,600			1,397,216,287			1,800,286,403			252,919,700			355,889,134
End of period	$	11,837,598,562		$	15,934,576,025		$	7,902,341,990		$	7,733,478,135		$	1,311,576,140		$	1,397,216,287		$	223,431,583		$	252,919,700
Undistributed (Overdistributed) net investment income (loss)	$	(14,257,690	)	$	(3,615,764	)	$	(32,804,029	)	$	(92,376,083	)	$	(2,316,494	)	$	(312,115	)	$	(5,561,522	)	$	(6,492,720	)

(a) Class R4 shares reflect activity for the period from June 25, 2014 (commencement of operations) through December 31, 2014.

See accompanying notes to financial statements.

	Columbia Acorn Select^SM						Columbia Thermostat Fund^SM						Columbia Acorn Emerging Markets Fund^SM						Columbia Acorn European Fund^SM
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,			(Unaudited) Six months ended June 30,			Year ended December 31,
	2015			2014			2015			2014			2015			2014			2015			2014 (a)
Subscriptions – Class R4		226,027			533,691			5,863,575			12,515,863			842,219			6,532,869			998,747			325,474
Distributions reinvested – Class R4		97,950			246,466			454,185			802,565			—			139,724			5,481			1,614
Redemptions – Class R4		(213,594	)		(753,003	)		(7,597,882	)		(4,731,799	)		(2,063,377	)		(3,899,691	)		(742,929	)		(93	)
Net Increase (Decrease) – Class R4		110,383			27,154			(1,280,122	)		8,586,629			(1,221,158	)		2,772,902			261,299			326,995
Subscriptions – Class R5		1,109,136			2,302,873			1,791,379			3,265,267			1,928,259			13,884,224			232,837			3,323,523
Distributions reinvested – Class R5		168,596			2,041,638			94,518			106,949			—			184,675			8,152			25,520
Redemptions – Class R5		(10,118,449	)		(3,845,123	)		(626,682	)		(815,418	)		(2,288,862	)		(7,252,982	)		(109,065	)		(3,409,088	)
Net Increase (Decrease) – Class R5		(8,840,717	)		499,388			1,259,215			2,556,798			(360,603	)		6,815,917			131,924			(60,045	)
Subscriptions – Class Y		1,049,300			538,245			17,030			435,256			—			—			—			—
Distributions reinvested – Class Y		308,428			714,565			6,853			14,183			—			—			—			—
Redemptions – Class Y		(787,637	)		(1,818,170	)		(81,317	)		(53,320	)		—			(200	)		—			—
Net Increase (Decrease) – Class Y		570,091			(565,360	)		(57,434	)		396,119			—			(200	)		—			—
Subscriptions – Class Z		7,799,032			41,269,615			43,253,933			158,234,941			20,668,240			181,236,447			6,255,614			21,621,093
Distributions reinvested – Class Z		17,593,307			52,107,171			4,862,392			8,772,626			—			2,002,496			56,774			139,509
Redemptions – Class Z		(61,063,835	)		(146,142,628	)		(80,807,320	)		(172,293,477	)		(48,814,280	)		(101,479,206	)		(2,236,638	)		(15,477,555	)
Net Increase (Decrease) – Class Z		(35,671,496	)		(52,765,842	)		(32,690,995	)		(5,285,910	)		(28,146,040	)		81,759,737			4,075,750			6,283,047
Net Increase (Decrease) from Share Transactions		(50,113,073	)		(68,020,990	)		(70,530,751	)		(102,748,851	)		(52,865,928	)		92,576,721			17,912,064			15,716,948
Total Increase (Decrease) in Net Assets		(61,827,942	)		(194,966,757	)		(82,111,511	)		(76,392,076	)		(65,463,062	)		67,630,453			19,851,265			9,848,283
Net Assets:
Beginning of period		666,576,786			861,543,543			1,260,413,061			1,336,805,137			482,335,107			414,704,654			36,632,808			26,784,525
End of period	$	604,748,844		$	666,576,786		$	1,178,301,550		$	1,260,413,061		$	416,872,045		$	482,335,107		$	56,484,073		$	36,632,808
Undistributed (Overdistributed) net investment income (loss)	$	(1,364,620	)	$	(325,960	)	$	9,640,304		$	1,675,197		$	186,119		$	(2,486,157	)	$	438,439		$	199,170

See accompanying notes to financial statements.

COLUMBIA ACORN FAMILY OF FUNDS

STATEMENTS OF CHANGES IN NET ASSETS, CONTINUED

		Columbia Acorn® Fund						Columbia Acorn International®						Columbia Acorn USA®						Columbia Acorn International Select^SM
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,			(Unaudited) Six months ended June 30,			Year ended December 31,
		2015			2014			2015			2014			2015			2014			2015			2014
Subscriptions – Class A			3,001,408			11,177,523			2,019,396			5,069,057			218,678			786,132			207,243			638,165
Shares issued in reinvestment and capital gains – Class A			3,518,818			14,955,024			186,041			1,433,668			114,990			878,620			8,141			298,993
Less shares redeemed – Class A			(23,581,767	)		(45,358,767	)		(2,688,008	)		(7,155,380	)		(916,961	)		(2,482,524	)		(707,956	)		(1,259,425	)
Net Increase (Decrease) – Class A			(17,061,541	)		(19,226,220	)		(482,571	)		(652,655	)		(583,293	)		(817,772	)		(492,572	)		(322,267	)
Shares issued in reinvestment and capital gains – Class B			8,196			53,837			899			10,251			171			1,994			5			2,445
Less shares redeemed – Class B			(144,946	)		(380,244	)		(68,720	)		(141,082	)		(4,445	)		(11,206	)		(10,810	)		(19,481	)
Net Increase (Decrease) – Class B			(136,750	)		(326,407	)		(67,821	)		(130,831	)		(4,274	)		(9,212	)		(10,805	)		(17,036	)
Subscriptions – Class C			730,815			2,380,665			149,874			455,251			34,670			106,036			19,698			43,902
Shares issued in reinvestment and capital gains – Class C			1,409,940			4,736,715			20,095			134,128			41,168			281,787			—			46,423
Less shares redeemed – Class C			(4,540,215	)		(6,832,781	)		(251,372	)		(471,635	)		(172,409	)		(259,303	)		(70,361	)		(104,212	)
Net Increase (Decrease) – Class C			(2,399,460	)		284,599			(81,403	)		117,744			(96,571	)		128,520			(50,663	)		(13,887	)
Subscriptions – Class I			385,749			2,381,215			839,510			2,360,586			—			—			—			—
Shares issued in reinvestment and capital gains – Class I			34,933			107,212			9,004			50,640			—			—			—			—
Less shares redeemed – Class I			(390,890	)		(2,154,531	)		(421,989	)		(2,111,846	)		—			(33	)		—			(4	)
Net Increase (Decrease) – Class I			29,792			333,896			426,525			299,380			—			(33	)		—			(4	)
Subscriptions – Class R			—			—			16,869			77,000			—			—			—			—
Shares issued in reinvestment and capital gains – Class R			—			—			876			7,564			—			—			—			—
Less shares redeemed – Class R			—			—			(35,993	)		(76,075	)		—			—			—			—
Net Increase (Decrease) – Class R			—			—			(18,248	)		8,489			—			—			—			—
Subscriptions – Class R4			809,837			5,988,744			2,024,389			3,770,182			180,371			69,547			8,955			36,025
Shares issued in reinvestment and capital gains – Class R4			283,521			658,166			94,930			626,322			9,198			40,840			191			5,756
Less shares redeemed – Class R4			(2,724,716	)		(900,585	)		(796,214	)		(1,864,318	)		(62,062	)		(35,802	)		(6,018	)		(13,656	)
Net Increase (Decrease) – Class R4	��		(1,631,358	)		5,746,325			1,323,105			2,532,186			127,507			74,585			3,128			28,125
Subscriptions – Class R5			1,017,113			5,371,622			1,367,792			5,374,903			143,679			1,039,918			59,649			113,565
Shares issued in reinvestment and capital gains – Class R5			278,701			2,508,272			82,020			636,802			31,087			188,407			616			13,893
Less shares redeemed – Class R5			(9,365,032	)		(6,914,002	)		(1,553,029	)		(2,352,664	)		(248,523	)		(237,562	)		(25,705	)		(46,841	)
Net Increase (Decrease) – Class R5			(8,069,218	)		965,892			(103,217	)		3,659,041			(73,757	)		990,763			34,560			80,617
Subscriptions – Class Y			484,810			5,405,607			1,777,478			2,180,767			41,219			989,024			200,381			95,911
Shares issued in reinvestment and capital gains – Class Y			296,663			2,114,206			48,099			346,391			26,733			182,296			1,908			63,827
Less shares redeemed – Class Y			(6,233,037	)		(28,273,237	)		(326,129	)		(474,107	)		(82,849	)		(1,378,135	)		(262,844	)		(122,660	)
Net Increase (Decrease) – Class Y			(5,451,564	)		(20,753,424	)		1,499,448			2,053,051			(14,897	)		(206,815	)		(60,555	)		37,078
Subscriptions – Class Z			7,992,106			27,275,542			7,316,293			18,575,064			2,094,137			2,943,870			308,447			1,572,550
Shares issued in reinvestment and capital gains – Class Z			10,790,770			50,258,476			845,796			6,885,453			716,812			5,614,121			17,995			645,241
Less shares redeemed – Class Z			(118,273,039	)		(116,645,260	)		(14,388,129	)		(26,436,650	)		(6,814,650	)		(13,762,562	)		(1,413,766	)		(3,750,710	)
Net Increase (Decrease) – Class Z			(99,490,163	)		(39,111,242	)		(6,226,040	)		(976,133	)		(4,003,701	)		(5,204,571	)		(1,087,324	)		(1,532,919	)
Net Increase (Decrease) in Shares of Beneficial Interest			(134,210,262	)		(72,086,581	)		(3,730,222	)		6,910,272			(4,648,986	)		(5,044,535	)		(1,664,231	)		(1,740,293	)

(a) Class R4 shares reflect activity for the period from June 25, 2014 (commencement of operations) through December 31, 2014.

See accompanying notes to financial statements.

	Columbia Acorn Select^SM						Columbia Thermostat Fund^SM						Columbia Acorn Emerging Markets Fund^SM						Columbia Acorn European Fund^SM
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,			(Unaudited) Six months ended June 30,			Year ended December 31,
	2015			2014			2015			2014			2015			2014			2015			2014 (a)
Subscriptions – Class A		385,509			999,673			3,052,476			7,304,585			537,683			8,480,721			1,036,044			1,976,901
Shares issued in reinvestment and capital gains – Class A		902,276			2,437,585			533,276			893,241			—			85,241			8,895			16,205
Less shares redeemed – Class A		(1,931,637	)		(3,902,541	)		(4,831,255	)		(13,113,073	)		(1,931,087	)		(9,160,435	)		(263,175	)		(1,738,341	)
Net Increase (Decrease) – Class A		(643,852	)		(465,283	)		(1,245,503	)		(4,915,247	)		(1,393,404	)		(594,473	)		781,764			254,765
Shares issued in reinvestment and capital gains – Class B		3,340			15,514			1,317			2,338			—			—			—			—
Less shares redeemed – Class B		(28,681	)		(88,114	)		(20,211	)		(74,245	)		—			—			—			—
Net Increase (Decrease) – Class B		(25,341	)		(72,600	)		(18,894	)		(71,907	)		—			—			—			—
Subscriptions – Class C		58,108			200,609			1,773,144			4,743,432			76,643			1,237,012			126,614			335,241
Shares issued in reinvestment and capital gains – Class C		210,504			546,759			401,349			519,687			—			—			—			1,380
Less shares redeemed – Class C		(422,778	)		(740,621	)		(3,417,847	)		(7,542,466	)		(490,751	)		(430,442	)		(40,534	)		(66,938	)
Net Increase (Decrease) – Class C		(154,166	)		6,747			(1,243,354	)		(2,279,347	)		(414,108	)		806,570			86,080			269,683
Subscriptions – Class I		808,777			2,177,235			—			—			—			—			—			—
Shares issued in reinvestment and capital gains – Class I		80,150			143,898			—			—			—			2			1			2
Less shares redeemed – Class I		(383,794	)		(1,994,457	)		—			—			—			(313	)		—			(346	)
Net Increase (Decrease) – Class I		505,133			326,676			—			—			—			(311	)		1			(344	)
Subscriptions – Class R		—			—			—			—			—			—			—			—
Shares issued in reinvestment and capital gains – Class R		—			—			—			—			—			—			—			—
Less shares redeemed – Class R		—			—			—			—			—			—			—			—
Net Increase (Decrease) – Class R		—			—			—			—			—			—			—			—
Subscriptions – Class R4		9,802			20,220			392,890			838,999			64,182			479,110			65,859			20,884
Shares issued in reinvestment and capital gains – Class R4		4,342			10,486			30,918			54,396			—			10,917			341			111
Less shares redeemed – Class R4		(9,260	)		(29,113	)		(509,605	)		(318,210	)		(161,433	)		(291,550	)		(48,223	)		(6	)
Net Increase (Decrease) – Class R4		4,884			1,593			(85,797	)		575,185			(97,251	)		198,477			17,977			20,989
Subscriptions – Class R5		47,798			87,557			120,660			219,576			149,120			1,041,821			14,668			208,383
Shares issued in reinvestment and capital gains – Class R5		7,460			87,341			6,425			7,242			—			14,425			505			1,646
Less shares redeemed – Class R5		(422,172	)		(146,321	)		(42,152	)		(54,794	)		(176,947	)		(536,066	)		(7,307	)		(216,692	)
Net Increase (Decrease) – Class R5		(366,914	)		28,577			84,933			172,024			(27,827	)		520,180			7,866			(6,663	)
Subscriptions – Class Y		44,436			20,305			1,139			29,656			—			—			—			—
Shares issued in reinvestment and capital gains – Class Y		13,593			30,390			466			962			—			—			—			—
Less shares redeemed – Class Y		(33,664	)		(69,067	)		(5,450	)		(3,571	)		—			(15	)		—			—
Net Increase (Decrease) – Class Y		24,365			(18,372	)		(3,845	)		27,047			—			(15	)		—			—
Subscriptions – Class Z		345,373			1,616,671			2,923,035			10,700,096			1,608,739			13,528,786			407,744			1,375,486
Shares issued in reinvestment and capital gains – Class Z		797,521			2,273,717			332,585			597,366			—			157,433			3,551			9,056
Less shares redeemed – Class Z		(2,703,400	)		(5,760,728	)		(5,453,493	)		(11,671,258	)		(3,816,904	)		(7,722,797	)		(151,860	)		(1,072,883	)
Net Increase (Decrease) – Class Z		(1,560,506	)		(1,870,340	)		(2,197,873	)		(373,796	)		(2,208,165	)		5,963,422			259,435			311,659
Net Increase (Decrease) in Shares of Beneficial Interest		(2,216,397	)		(2,063,002	)		(4,710,333	)		(6,866,041	)		(4,140,755	)		6,893,850			1,153,123			850,089

See accompanying notes to financial statements.

COLUMBIA ACORN FAMILY OF FUNDS

FINANCIAL HIGHLIGHTS

The following tables are intended to help you understand the Fund's financial performance. Certain information reflects financial results for a single share of a class held for the periods shown. Per share net investment income (loss) amounts are calculated based on average shares outstanding during the period. Total return assumes reinvestment of all dividends and distributions, if any. Total return does not reflect payment of sales charges, if any. Total return and portfolio turnover are not annualized for periods of less than one year. The portfolio turnover rate is calculated without regard to purchase and sales transactions of short-term instruments and certain derivatives, if any. If such transactions were included, the Fund's portfolio turnover rate may be higher.

Columbia Acorn® Fund

			Income from Investment Operations									Less Distributions to Shareholders
(Selected data for a share outstanding throughout each period)	Net Asset Value, Beginning of Period		Net investment income (loss)			Net realized and unrealized gain (loss)			Total from Investment Operations			Net investment income			Net realized gains			Total Distributions to Shareholders			Increase from regulatory settlements
Class A
Six Months Ended June 30, 2015 (Unaudited)	$	30.30		(0.05	)		2.02			1.97			—			(1.64	)		(1.64	)		—
Year Ended December 31, 2014	$	35.78		(0.08	)		0.21			0.13			—			(5.61	)		(5.61	)		—
Year Ended December 31, 2013	$	29.36		(0.06	)		8.84			8.78			(0.04	)		(2.32	)		(2.36	)		—
Year Ended December 31, 2012	$	26.63		0.08			4.53			4.61			(0.06	)		(1.82	)		(1.88	)		—
Year Ended December 31, 2011	$	29.24		(0.10	)		(1.30	)		(1.40	)		(0.02	)		(1.19	)		(1.21	)		—
Year Ended December 31, 2010	$	23.98		(0.06	)		6.18			6.12			(0.02	)		(0.84	)		(0.86	)		0.00	(d)
Class B
Six Months Ended June 30, 2015 (Unaudited)	$	26.53		(0.16	)		1.78			1.62			—			(1.64	)		(1.64	)		—
Year Ended December 31, 2014	$	32.25		(0.29	)		0.18			(0.11	)		—			(5.61	)		(5.61	)		—
Year Ended December 31, 2013	$	26.80		(0.25	)		8.02			7.77			—			(2.32	)		(2.32	)		—
Year Ended December 31, 2012	$	24.53		(0.11	)		4.20			4.09			—			(1.82	)		(1.82	)		—
Year Ended December 31, 2011	$	27.14		(0.27	)		(1.15	)		(1.42	)		—			(1.19	)		(1.19	)		—
Year Ended December 31, 2010	$	22.43		(0.21	)		5.76			5.55			—			(0.84	)		(0.84	)		0.00	(d)
Class C
Six Months Ended June 30, 2015 (Unaudited)	$	25.92		(0.14	)		1.73			1.59			—			(1.64	)		(1.64	)		—
Year Ended December 31, 2014	$	31.64		(0.28	)		0.17			(0.11	)		—			(5.61	)		(5.61	)		—
Year Ended December 31, 2013	$	26.34		(0.26	)		7.88			7.62			—			(2.32	)		(2.32	)		—
Year Ended December 31, 2012	$	24.18		(0.12	)		4.10			3.98			—			(1.82	)		(1.82	)		—
Year Ended December 31, 2011	$	26.85		(0.29	)		(1.19	)		(1.48	)		—			(1.19	)		(1.19	)		—
Year Ended December 31, 2010	$	22.23		(0.24	)		5.70			5.46			—			(0.84	)		(0.84	)		0.00	(d)
Class I
Six Months Ended June 30, 2015 (Unaudited)	$	32.03		0.01			2.13			2.14			—			(1.64	)		(1.64	)		—
Year Ended December 31, 2014	$	37.37		0.05			0.22			0.27			—			(5.61	)		(5.61	)		—
Year Ended December 31, 2013	$	30.47		0.06			9.20			9.26			(0.04	)		(2.32	)		(2.36	)		—
Year Ended December 31, 2012	$	27.57		0.26			4.62			4.88			(0.16	)		(1.82	)		(1.98	)		—
Year Ended December 31, 2011	$	30.19		0.01			(1.35	)		(1.34	)		(0.09	)		(1.19	)		(1.28	)		—
Year Ended December 31, 2010(e)	$	26.80		(0.01	)		4.26			4.25			(0.02	)		(0.84	)		(0.86	)		—
Class R4
Six Months Ended June 30, 2015 (Unaudited)	$	32.51		(0.02	)		2.17			2.15			—			(1.64	)		(1.64	)		—
Year Ended December 31, 2014	$	37.88		0.02			0.22			0.24			—			(5.61	)		(5.61	)		—
Year Ended December 31, 2013	$	30.90		0.06			9.29			9.35			(0.05	)		(2.32	)		(2.37	)		—
Year Ended December 31, 2012(f)	$	30.59		0.05			1.84			1.89			(0.12	)		(1.46	)		(1.58	)		—
Class R5
Six Months Ended June 30, 2015 (Unaudited)	$	32.55		(0.01	)		2.17			2.16			—			(1.64	)		(1.64	)		—
Year Ended December 31, 2014	$	37.89		0.04			0.23			0.27			—			(5.61	)		(5.61	)		—
Year Ended December 31, 2013	$	30.88		0.07			9.30			9.37			(0.04	)		(2.32	)		(2.36	)		—
Year Ended December 31, 2012(g)	$	30.59		0.06			1.83			1.89			(0.14	)		(1.46	)		(1.60	)		—
Class Y
Six Months Ended June 30, 2015 (Unaudited)	$	32.61		0.00	(d)		2.18			2.18			—			(1.64	)		(1.64	)		—
Year Ended December 31, 2014	$	37.93		0.05			0.24			0.29			—			(5.61	)		(5.61	)		—
Year Ended December 31, 2013	$	30.90		0.09			9.31			9.40			(0.05	)		(2.32	)		(2.37	)		—
Year Ended December 31, 2012(h)	$	30.62		0.09			1.80			1.89			(0.15	)		(1.46	)		(1.61	)		—
Class Z
Six Months Ended June 30, 2015 (Unaudited)	$	31.95		(0.01	)		2.14			2.13			—			(1.64	)		(1.64	)		—
Year Ended December 31, 2014	$	37.32		0.02			0.22			0.24			—			(5.61	)		(5.61	)		—
Year Ended December 31, 2013	$	30.45		0.04			9.19			9.23			(0.04	)		(2.32	)		(2.36	)		—
Year Ended December 31, 2012	$	27.56		0.17			4.69			4.86			(0.15	)		(1.82	)		(1.97	)		—
Year Ended December 31, 2011	$	30.19		(0.01	)		(1.34	)		(1.35	)		(0.09	)		(1.19	)		(1.28	)		—
Year Ended December 31, 2010	$	24.68		0.02			6.37			6.39			(0.04	)		(0.84	)		(0.88	)		0.00	(d)

Notes to Financial Highlights

(a) In addition to the fees and expenses that the Fund bears directly, the Fund indirectly bears a pro rata share of the fees and expenses of any other funds in which it invests, if any. Such indirect expenses are not included in the Fund's reported expense ratios.

(b) Annualized.

(d) Rounds to zero.

(e) Class I shares commenced operations on September 27, 2010. Per share data and total return reflect activity from that date.

(f) Class R4 shares commenced operations on November 8, 2012. Per share data and total return reflect activity from that date.

(g) Class R5 shares commenced operations on November 8, 2012. Per share data and total return reflect activity from that date.

(h) Class Y shares commenced operations on November 8, 2012. Per share data and total return reflect activity from that date.

See accompanying notes to financial statements.

						Ratio to Average Net Assets									Supplemental Data
(Selected data for a share outstanding throughout each period)	Net Asset Value, End of Period		Total Return			Total gross expenses (a)			Total net expenses (a)			Net investment income (loss)			Portfolio turnover rate			Net assets, end of period (000s)
Class A
Six Months Ended June 30, 2015 (Unaudited)	$	30.63		6.45	%		1.09	%(b)		1.09	%(b)		(0.33	)%(b)		10	%	$	2,201,585
Year Ended December 31, 2014	$	30.30		0.55	%		1.08	%		1.08	%		(0.22	)%		17	%	$	2,694,610
Year Ended December 31, 2013	$	35.78		30.53	%		1.07	%		1.07	%		(0.17	)%		18	%	$	3,869,734
Year Ended December 31, 2012	$	29.36		17.62	%		1.06	%		1.06	%(c)		0.27	%		16	%	$	3,233,494
Year Ended December 31, 2011	$	26.63		(4.91	)%		1.06	%		1.06	%(c)		(0.33	)%		18	%	$	3,246,833
Year Ended December 31, 2010	$	29.24		25.61	%		1.07	%		1.07	%(c)		(0.22	)%		28	%	$	3,639,788
Class B
Six Months Ended June 30, 2015 (Unaudited)	$	26.51		6.04	%		1.89	%(b)		1.89	%(b)		(1.16	)%(b)		10	%	$	3,570
Year Ended December 31, 2014	$	26.53		(0.16	)%		1.75	%		1.75	%		(0.91	)%		17	%	$	7,201
Year Ended December 31, 2013	$	32.25		29.63	%		1.73	%		1.73	%		(0.84	)%		18	%	$	19,278
Year Ended December 31, 2012	$	26.80		16.98	%		1.65	%		1.64	%(c)		(0.42	)%		16	%	$	33,623
Year Ended December 31, 2011	$	24.53		(5.34	)%		1.67	%		1.67	%(c)		(0.98	)%		18	%	$	67,153
Year Ended December 31, 2010	$	27.14		24.81	%		1.69	%		1.69	%(c)		(0.88	)%		28	%	$	287,650
Class C
Six Months Ended June 30, 2015 (Unaudited)	$	25.87		6.07	%		1.79	%(b)		1.79	%(b)		(1.03	)%(b)		10	%	$	712,926
Year Ended December 31, 2014	$	25.92		(0.16	)%		1.77	%		1.77	%		(0.92	)%		17	%	$	776,370
Year Ended December 31, 2013	$	31.64		29.58	%		1.78	%		1.78	%		(0.88	)%		18	%	$	938,644
Year Ended December 31, 2012	$	26.34		16.77	%		1.80	%		1.80	%(c)		(0.46	)%		16	%	$	756,709
Year Ended December 31, 2011	$	24.18		(5.63	)%		1.82	%		1.82	%(c)		(1.10	)%		18	%	$	721,446
Year Ended December 31, 2010	$	26.85		24.63	%		1.85	%		1.85	%(c)		(1.00	)%		28	%	$	829,181
Class I
Six Months Ended June 30, 2015 (Unaudited)	$	32.53		6.63	%		0.72	%(b)		0.72	%(b)		0.03	%(b)		10	%	$	29,576
Year Ended December 31, 2014	$	32.03		0.91	%		0.70	%		0.70	%		0.14	%		17	%	$	28,164
Year Ended December 31, 2013	$	37.37		30.99	%		0.70	%		0.70	%		0.16	%		18	%	$	20,383
Year Ended December 31, 2012	$	30.47		18.02	%		0.72	%		0.72	%(c)		0.86	%		16	%	$	58,652
Year Ended December 31, 2011	$	27.57		(4.57	)%		0.72	%		0.72	%(c)		0.02	%		18	%	$	16,397
Year Ended December 31, 2010(e)	$	30.19		15.94	%		0.71	%(b)		0.71	%(b)(c)		(0.13	)%(b)		28	%	$	11,627
Class R4
Six Months Ended June 30, 2015 (Unaudited)	$	33.02		6.56	%		0.87	%(b)		0.87	%(b)		(0.11	)%(b)		10	%	$	200,539
Year Ended December 31, 2014	$	32.51		0.81	%		0.84	%		0.84	%		0.05	%		17	%	$	250,457
Year Ended December 31, 2013	$	37.88		30.85	%		0.80	%		0.80	%		0.16	%		18	%	$	74,188
Year Ended December 31, 2012(f)	$	30.90		6.31	%		0.87	%(b)		0.86	%(b)(c)		1.24	%(b)		16	%	$	17
Class R5
Six Months Ended June 30, 2015 (Unaudited)	$	33.07		6.58	%		0.77	%(b)		0.77	%(b)		(0.04	)%(b)		10	%	$	198,784
Year Ended December 31, 2014	$	32.55		0.89	%		0.76	%		0.76	%		0.10	%		17	%	$	458,223
Year Ended December 31, 2013	$	37.89		30.94	%		0.75	%		0.75	%		0.20	%		18	%	$	496,906
Year Ended December 31, 2012(g)	$	30.88		6.33	%		0.82	%(b)		0.81	%(b)(c)		1.29	%(b)		16	%	$	3
Class Y
Six Months Ended June 30, 2015 (Unaudited)	$	33.15		6.63	%		0.72	%(b)		0.72	%(b)		0.00	%(b)(d)		10	%	$	204,378
Year Ended December 31, 2014	$	32.61		0.94	%		0.70	%		0.70	%		0.13	%		17	%	$	378,780
Year Ended December 31, 2013	$	37.93		30.99	%		0.70	%		0.70	%		0.26	%		18	%	$	1,227,891
Year Ended December 31, 2012(h)	$	30.90		6.34	%		0.75	%(b)		0.75	%(b)(c)		2.21	%(b)		16	%	$	67,012
Class Z
Six Months Ended June 30, 2015 (Unaudited)	$	32.44		6.61	%		0.80	%(b)		0.80	%(b)		(0.05	)%(b)		10	%	$	8,286,240
Year Ended December 31, 2014	$	31.95		0.82	%		0.79	%		0.79	%		0.07	%		17	%	$	11,340,770
Year Ended December 31, 2013	$	37.32		30.90	%		0.78	%		0.78	%		0.12	%		18	%	$	14,703,948
Year Ended December 31, 2012	$	30.45		17.93	%		0.78	%		0.78	%(c)		0.57	%		16	%	$	13,374,355
Year Ended December 31, 2011	$	27.56		(4.61	)%		0.76	%		0.76	%(c)		(0.03	)%		18	%	$	12,284,748
Year Ended December 31, 2010	$	30.19		26.00	%		0.76	%		0.76	%(c)		0.09	%		28	%	$	13,330,466

See accompanying notes to financial statements.

COLUMBIA ACORN FAMILY OF FUNDS

FINANCIAL HIGHLIGHTS, CONTINUED

Columbia Acorn International®

			Income from Investment Operations												Less Distributions to Shareholders
(Selected data for a share outstanding throughout each period)	Net Asset Value, Beginning of Period		Net investment income (loss)			Net realized and unrealized gain (loss)			Reimbursement from affiliate			Total from Investment Operations			Net investment income			Net realized gains			Total Distributions to Shareholders			Redemption fees added to paid in capital
Class A
Six Months Ended June 30, 2015 (Unaudited)	$	41.68		0.27			1.84			—			2.11			—			(0.38	)		(0.38	)		—
Year Ended December 31, 2014	$	46.63		0.42			(2.51	)		—			(2.09	)		(0.55	)		(2.31	)		(2.86	)		—
Year Ended December 31, 2013	$	40.79		0.45			8.37			—			8.82			(1.05	)		(1.93	)		(2.98	)		—
Year Ended December 31, 2012	$	34.15		0.47			6.75			—			7.22			(0.58	)		—			(0.58	)		—
Year Ended December 31, 2011	$	40.87		0.32			(6.02	)		0.00	(d)		(5.70	)		(1.02	)		—			(1.02	)		—
Year Ended December 31, 2010	$	34.13		0.22			7.21			—			7.43			(0.69	)		—			(0.69	)		0.00	(d)
Class B
Six Months Ended June 30, 2015 (Unaudited)	$	40.38		0.06			1.81			—			1.87			—			(0.38	)		(0.38	)		—
Year Ended December 31, 2014	$	45.24		0.07			(2.42	)		—			(2.35	)		(0.20	)		(2.31	)		(2.51	)		—
Year Ended December 31, 2013	$	39.67		0.12			8.10			—			8.22			(0.72	)		(1.93	)		(2.65	)		—
Year Ended December 31, 2012	$	33.17		0.19			6.55			—			6.74			(0.24	)		—			(0.24	)		—
Year Ended December 31, 2011	$	39.96		0.06			(5.85	)		0.00	(d)		(5.79	)		(1.00	)		—			(1.00	)		—
Year Ended December 31, 2010	$	33.22		0.03			7.02			—			7.05			(0.31	)		—			(0.31	)		0.00	(d)
Class C
Six Months Ended June 30, 2015 (Unaudited)	$	40.20		0.11			1.76			—			1.87			—			(0.38	)		(0.38	)		—
Year Ended December 31, 2014	$	45.04		0.07			(2.40	)		—			(2.33	)		(0.20	)		(2.31	)		(2.51	)		—
Year Ended December 31, 2013	$	39.50		0.10			8.08			—			8.18			(0.71	)		(1.93	)		(2.64	)		—
Year Ended December 31, 2012	$	33.03		0.18			6.52			—			6.70			(0.23	)		—			(0.23	)		—
Year Ended December 31, 2011	$	39.79		0.04			(5.86	)		0.00	(d)		(5.82	)		(0.94	)		—			(0.94	)		—
Year Ended December 31, 2010	$	33.08		(0.05	)		7.03			—			6.98			(0.27	)		—			(0.27	)		0.00	(d)
Class I
Six Months Ended June 30, 2015 (Unaudited)	$	41.76		0.35			1.84			—			2.19			—			(0.38	)		(0.38	)		—
Year Ended December 31, 2014	$	46.71		0.59			(2.51	)		—			(1.92	)		(0.72	)		(2.31	)		(3.03	)		—
Year Ended December 31, 2013	$	40.86		0.66			8.34			—			9.00			(1.22	)		(1.93	)		(3.15	)		—
Year Ended December 31, 2012	$	34.33		0.57			6.83			—			7.40			(0.87	)		—			(0.87	)		—
Year Ended December 31, 2011	$	40.92		0.37			(5.94	)		0.00	(d)		(5.57	)		(1.02	)		—			(1.02	)		—
Year Ended December 31, 2010(g)	$	37.69		0.08			3.49			—			3.57			(0.34	)		—			(0.34	)		0.00	(d)
Class R
Six Months Ended June 30, 2015 (Unaudited)	$	41.67		0.19			1.84			—			2.03			—			(0.38	)		(0.38	)		—
Year Ended December 31, 2014	$	46.60		0.24			(2.50	)		—			(2.26	)		(0.36	)		(2.31	)		(2.67	)		—
Year Ended December 31, 2013	$	40.79		0.26			8.36			—			8.62			(0.88	)		(1.93	)		(2.81	)		—
Year Ended December 31, 2012	$	34.11		0.21			6.89			—			7.10			(0.42	)		—			(0.42	)		—
Year Ended December 31, 2011(h)	$	40.11		(0.00	)(d)		(6.00	)		0.00	(d)		(6.00	)		—			—			—			—
Class R4
Six Months Ended June 30, 2015 (Unaudited)	$	42.02		0.33			1.83			—			2.16			—			(0.38	)		(0.38	)		—
Year Ended December 31, 2014	$	46.99		0.50			(2.52	)		—			(2.02	)		(0.64	)		(2.31	)		(2.95	)		—
Year Ended December 31, 2013	$	41.08		0.34			8.67			—			9.01			(1.17	)		(1.93	)		(3.10	)		—
Year Ended December 31, 2012(i)	$	39.86		(0.00	)(d)		1.81			—			1.81			(0.59	)		—			(0.59	)		—
Class R5
Six Months Ended June 30, 2015 (Unaudited)	$	41.71		0.35			1.82			—			2.17			—			(0.38	)		(0.38	)		—
Year Ended December 31, 2014	$	46.66		0.57			(2.51	)		—			(1.94	)		(0.70	)		(2.31	)		(3.01	)		—
Year Ended December 31, 2013	$	40.81		0.63			8.34			—			8.97			(1.19	)		(1.93	)		(3.12	)		—
Year Ended December 31, 2012	$	34.31		0.75			6.62			—			7.37			(0.87	)		—			(0.87	)		—
Year Ended December 31, 2011(j)	$	40.24		0.09			(6.02	)		0.00	(d)		(5.93	)		—			—			—			—
Class Y
Six Months Ended June 30, 2015 (Unaudited)	$	42.02		0.36			1.85			—			2.21			—			(0.38	)		(0.38	)		—
Year Ended December 31, 2014	$	46.99		0.58			(2.52	)		—			(1.94	)		(0.72	)		(2.31	)		(3.03	)		—
Year Ended December 31, 2013	$	41.08		0.57			8.48			—			9.05			(1.21	)		(1.93	)		(3.14	)		—
Year Ended December 31, 2012(k)	$	39.90		0.04			1.78			—			1.82			(0.64	)		—			(0.64	)		—
Class Z
Six Months Ended June 30, 2015 (Unaudited)	$	41.73		0.34			1.83			—			2.17			—			(0.38	)		(0.38	)		—
Year Ended December 31, 2014	$	46.68		0.56			(2.51	)		—			(1.95	)		(0.69	)		(2.31	)		(3.00	)		—
Year Ended December 31, 2013	$	40.84		0.58			8.38			—			8.96			(1.19	)		(1.93	)		(3.12	)		—
Year Ended December 31, 2012	$	34.31		0.59			6.78			—			7.37			(0.84	)		—			(0.84	)		—
Year Ended December 31, 2011	$	40.92		0.48			(6.07	)		0.00	(d)		(5.59	)		(1.02	)		—			(1.02	)		—
Year Ended December 31, 2010	$	34.26		0.35			7.23			—			7.58			(0.92	)		—			(0.92	)		0.00	(d)

Notes to Financial Highlights

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

(d) Rounds to zero.

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

(f) During the year ended December 31, 2011, Columbia Management reimbursed the Fund for a loss on a trading error. Had the Fund not received this reimbursement, total return would have been lower by less than 0.01%.

(g) Class I shares commenced operations on September 27, 2010. Per share data and total return reflect activity from that date.

(h) Class R shares commenced operations on August 2, 2011. Per share data and total return reflect activity from that date.

(i) Class R4 shares commenced operations on November 8, 2012. Per share data and total return reflect activity from that date.

(j) Class R5 shares commenced operations on August 2, 2011. Per share data and total return reflect activity from that date.

(k) Class Y shares commenced operations on November 8, 2012. Per share data and total return reflect activity from that date.

See accompanying notes to financial statements.

									Ratio to Average Net Assets									Supplemental Data
(Selected data for a share outstanding throughout each period)	Increase from regulatory settlements			Net Asset Value, End of Period		Total Return			Total gross expenses (a)			Total net expenses (a)			Net investment income (loss)			Portfolio turnover rate			Net assets, end of period (000s)
Class A
Six Months Ended June 30, 2015 (Unaudited)		—		$	43.41		5.05	%(b)		1.28	%(c)		1.24	%(c)		1.27	%(c)		23	%	$	964,828
Year Ended December 31, 2014		—		$	41.68		(4.58	)%(b)		1.26	%		1.22	%		0.91	%		28	%	$	946,553
Year Ended December 31, 2013		—		$	46.63		22.00	%(b)		1.27	%		1.23	%		1.02	%		45	%	$	1,089,263
Year Ended December 31, 2012		0.00	(d)	$	40.79		21.21	%(b)		1.28	%		1.24	%(e)		1.22	%		33	%	$	1,007,236
Year Ended December 31, 2011		0.00	(d)	$	34.15		(14.37	)%(b)(f)		1.32	%		1.30	%(e)		0.84	%		32	%	$	918,112
Year Ended December 31, 2010		0.00	(d)	$	40.87		22.23	%		1.35	%		1.35	%(e)		0.62	%		25	%	$	810,603
Class B
Six Months Ended June 30, 2015 (Unaudited)		—		$	41.87		4.61	%(b)		2.11	%(c)		2.08	%(c)		0.28	%(c)		23	%	$	3,915
Year Ended December 31, 2014		—		$	40.38		(5.29	)%(b)		2.00	%		1.97	%		0.16	%		28	%	$	6,516
Year Ended December 31, 2013		—		$	45.24		21.08	%(b)		2.00	%		1.97	%		0.27	%		45	%	$	13,218
Year Ended December 31, 2012		0.00	(d)	$	39.67		20.33	%(b)		2.00	%		1.97	%(e)		0.51	%		33	%	$	17,910
Year Ended December 31, 2011		0.00	(d)	$	33.17		(14.92	)%(b)(f)		1.98	%		1.96	%(e)		0.15	%		32	%	$	24,510
Year Ended December 31, 2010		0.00	(d)	$	39.96		21.49	%		1.96	%		1.96	%(e)		0.08	%		25	%	$	29,368
Class C
Six Months Ended June 30, 2015 (Unaudited)		—		$	41.69		4.63	%(b)		2.00	%(c)		1.98	%(c)		0.52	%(c)		23	%	$	104,160
Year Ended December 31, 2014		—		$	40.20		(5.27	)%(b)		1.99	%		1.97	%		0.16	%		28	%	$	103,691
Year Ended December 31, 2013		—		$	45.04		21.07	%(b)		2.01	%		1.99	%		0.23	%		45	%	$	110,875
Year Ended December 31, 2012		0.00	(d)	$	39.50		20.31	%(b)		2.02	%		2.00	%(e)		0.48	%		33	%	$	92,748
Year Ended December 31, 2011		0.00	(d)	$	33.03		(15.02	)%(b)(f)		2.07	%		2.06	%(e)		0.10	%		32	%	$	97,328
Year Ended December 31, 2010		0.00	(d)	$	39.79		21.34	%		2.11	%		2.11	%(e)		(0.13	)%		25	%	$	110,931
Class I
Six Months Ended June 30, 2015 (Unaudited)		—		$	43.57		5.23	%		0.87	%(c)		0.87	%(c)		1.64	%(c)		23	%	$	59,074
Year Ended December 31, 2014		—		$	41.76		(4.20	)%		0.85	%		0.85	%		1.26	%		28	%	$	38,804
Year Ended December 31, 2013		—		$	46.71		22.43	%		0.85	%		0.85	%		1.49	%		45	%	$	29,418
Year Ended December 31, 2012		0.00	(d)	$	40.86		21.69	%		0.88	%		0.88	%(e)		1.48	%		33	%	$	97,484
Year Ended December 31, 2011		0.00	(d)	$	34.33		(14.02	)%(f)		0.91	%		0.91	%(e)		0.99	%		32	%	$	50,335
Year Ended December 31, 2010(g)		—		$	40.92		9.50	%		0.94	%(c)		0.94	%(c)(e)		0.77	%(c)		25	%	$	66,581
Class R
Six Months Ended June 30, 2015 (Unaudited)		—		$	43.32		4.86	%		1.60	%(c)		1.60	%(c)		0.89	%(c)		23	%	$	4,989
Year Ended December 31, 2014		—		$	41.67		(4.95	)%		1.63	%		1.63	%		0.52	%		28	%	$	5,560
Year Ended December 31, 2013		—		$	46.60		21.50	%		1.63	%		1.63	%		0.58	%		45	%	$	5,822
Year Ended December 31, 2012		0.00	(d)	$	40.79		20.83	%		1.52	%		1.51	%(e)		0.54	%		33	%	$	2,799
Year Ended December 31, 2011(h)		0.00	(d)	$	34.11		(14.96	)%		1.59	%(c)		1.59	%(c)(e)		(0.02	)%(c)		32	%	$	2,130
Class R4
Six Months Ended June 30, 2015 (Unaudited)		—		$	43.80		5.12	%		1.05	%(c)		1.05	%(c)		1.49	%(c)		23	%	$	500,423
Year Ended December 31, 2014		—		$	42.02		(4.39	)%		1.04	%		1.04	%		1.07	%		28	%	$	424,425
Year Ended December 31, 2013		—		$	46.99		22.32	%		1.03	%		1.03	%		0.73	%		45	%	$	355,616
Year Ended December 31, 2012(i)		—		$	41.08		4.57	%		1.03	%(c)		1.02	%(c)(e)		(0.02	)%(c)		33	%	$	15
Class R5
Six Months Ended June 30, 2015 (Unaudited)		—		$	43.50		5.19	%		0.91	%(c)		0.91	%(c)		1.60	%(c)		23	%	$	410,552
Year Ended December 31, 2014		—		$	41.71		(4.25	)%		0.90	%		0.90	%		1.23	%		28	%	$	397,882
Year Ended December 31, 2013		—		$	46.66		22.38	%		0.91	%		0.91	%		1.40	%		45	%	$	274,415
Year Ended December 31, 2012		0.00	(d)	$	40.81		21.61	%		0.89	%		0.89	%(e)		1.99	%		33	%	$	242
Year Ended December 31, 2011(j)		0.00	(d)	$	34.31		(14.74	)%		0.91	%(c)		0.91	%(c)(e)		0.65	%(c)		32	%	$	2,038
Class Y
Six Months Ended June 30, 2015 (Unaudited)		—		$	43.85		5.24	%		0.87	%(c)		0.87	%(c)		1.66	%(c)		23	%	$	300,536
Year Ended December 31, 2014		—		$	42.02		(4.21	)%		0.85	%		0.85	%		1.25	%		28	%	$	225,012
Year Ended December 31, 2013		—		$	46.99		22.44	%		0.86	%		0.86	%		1.26	%		45	%	$	155,140
Year Ended December 31, 2012(k)		—		$	41.08		4.59	%		0.91	%(c)		0.90	%(c)(e)		0.75	%(c)		33	%	$	30,856
Class Z
Six Months Ended June 30, 2015 (Unaudited)		—		$	43.52		5.18	%		0.95	%(c)		0.95	%(c)		1.55	%(c)		23	%	$	5,553,864
Year Ended December 31, 2014		—		$	41.73		(4.28	)%		0.93	%		0.93	%		1.20	%		28	%	$	5,585,035
Year Ended December 31, 2013		—		$	46.68		22.33	%		0.93	%		0.93	%		1.30	%		45	%	$	6,293,552
Year Ended December 31, 2012		0.00	(d)	$	40.84		21.60	%		0.93	%		0.93	%(e)		1.53	%		33	%	$	5,494,506
Year Ended December 31, 2011		0.00	(d)	$	34.31		(14.06	)%(f)		0.95	%		0.95	%(e)		1.24	%		32	%	$	4,322,500
Year Ended December 31, 2010		0.00	(d)	$	40.92		22.70	%		0.97	%		0.97	%(e)		0.99	%		25	%	$	5,107,580

See accompanying notes to financial statements.

COLUMBIA ACORN FAMILY OF FUNDS

FINANCIAL HIGHLIGHTS, CONTINUED

Columbia Acorn USA®

			Income from Investment Operations									Less Distributions to Shareholders
(Selected data for a share outstanding throughout each period)	Net Asset Value, Beginning of Period		Net investment income (loss)			Net realized and unrealized gain (loss)			Total from Investment Operations			Net investment income			Net realized gains			Total Distributions to Shareholders
Class A
Six Months Ended June 30, 2015 (Unaudited)	$	29.13		(0.07	)		2.16			2.09			—			(0.84	)		(0.84	)
Year Ended December 31, 2014	$	34.15		(0.20	)		1.22			1.02			—			(6.04	)		(6.04	)
Year Ended December 31, 2013	$	28.21		(0.15	)		9.09			8.94			—			(3.00	)		(3.00	)
Year Ended December 31, 2012	$	25.94		0.02			4.73			4.75			(0.11	)		(2.37	)		(2.48	)
Year Ended December 31, 2011	$	27.54		(0.22	)		(1.21	)		(1.43	)		—			(0.17	)		(0.17	)
Year Ended December 31, 2010	$	22.43		(0.15	)		5.26			5.11			—			—			—
Class B
Six Months Ended June 30, 2015 (Unaudited)	$	25.27		(0.22	)		1.86			1.64			—			(0.84	)		(0.84	)
Year Ended December 31, 2014	$	30.70		(0.46	)		1.07			0.61			—			(6.04	)		(6.04	)
Year Ended December 31, 2013	$	25.81		(0.39	)		8.28			7.89			—			(3.00	)		(3.00	)
Year Ended December 31, 2012	$	23.98		(0.19	)		4.39			4.20			—			(2.37	)		(2.37	)
Year Ended December 31, 2011	$	25.60		(0.37	)		(1.08	)		(1.45	)		—			(0.17	)		(0.17	)
Year Ended December 31, 2010	$	20.99		(0.30	)		4.91			4.61			—			—			—
Class C
Six Months Ended June 30, 2015 (Unaudited)	$	24.98		(0.15	)		1.85			1.70			—			(0.84	)		(0.84	)
Year Ended December 31, 2014	$	30.33		(0.37	)		1.06			0.69			—			(6.04	)		(6.04	)
Year Ended December 31, 2013	$	25.49		(0.33	)		8.17			7.84			—			(3.00	)		(3.00	)
Year Ended December 31, 2012	$	23.72		(0.16	)		4.30			4.14			—			(2.37	)		(2.37	)
Year Ended December 31, 2011	$	25.39		(0.39	)		(1.11	)		(1.50	)		—			(0.17	)		(0.17	)
Year Ended December 31, 2010	$	20.84		(0.31	)		4.86			4.55			—			—			—
Class I
Six Months Ended June 30, 2015 (Unaudited)	$	31.19		(0.02	)		2.32			2.30			—			(0.84	)		(0.84	)
Year Ended December 31, 2014	$	35.99		(0.06	)		1.30			1.24			—			(6.04	)		(6.04	)
Year Ended December 31, 2013	$	29.47		(0.02	)		9.54			9.52			—			(3.00	)		(3.00	)
Year Ended December 31, 2012	$	27.00		(0.10	)		5.16			5.06			(0.22	)		(2.37	)		(2.59	)
Year Ended December 31, 2011	$	28.56		(0.14	)		(1.25	)		(1.39	)		—			(0.17	)		(0.17	)
Year Ended December 31, 2010(e)	$	24.24		(0.03	)		4.35			4.32			—			—			—
Class R4
Six Months Ended June 30, 2015 (Unaudited)	$	31.70		(0.04	)		2.35			2.31			—			(0.84	)		(0.84	)
Year Ended December 31, 2014	$	36.55		(0.11	)		1.30			1.19			—			(6.04	)		(6.04	)
Year Ended December 31, 2013	$	29.92		0.00	(f)		9.63			9.63			—			(3.00	)		(3.00	)
Year Ended December 31, 2012(g)	$	30.06		0.06			2.28			2.34			(0.16	)		(2.32	)		(2.48	)
Class R5
Six Months Ended June 30, 2015 (Unaudited)	$	31.71		(0.03	)		2.36			2.33			—			(0.84	)		(0.84	)
Year Ended December 31, 2014	$	36.53		(0.06	)		1.28			1.22			—			(6.04	)		(6.04	)
Year Ended December 31, 2013	$	29.90		0.02			9.61			9.63			—			(3.00	)		(3.00	)
Year Ended December 31, 2012(h)	$	30.06		0.07			2.27			2.34			(0.18	)		(2.32	)		(2.50	)
Class Y
Six Months Ended June 30, 2015 (Unaudited)	$	31.80		(0.02	)		2.36			2.34			—			(0.84	)		(0.84	)
Year Ended December 31, 2014	$	36.59		(0.07	)		1.32			1.25			—			(6.04	)		(6.04	)
Year Ended December 31, 2013	$	29.93		0.02			9.64			9.66			—			(3.00	)		(3.00	)
Year Ended December 31, 2012(i)	$	30.10		0.07			2.27			2.34			(0.19	)		(2.32	)		(2.51	)
Class Z
Six Months Ended June 30, 2015 (Unaudited)	$	31.03		(0.04	)		2.30			2.26			—			(0.84	)		(0.84	)
Year Ended December 31, 2014	$	35.90		(0.12	)		1.29			1.17			—			(6.04	)		(6.04	)
Year Ended December 31, 2013	$	29.45		(0.07	)		9.52			9.45			—			(3.00	)		(3.00	)
Year Ended December 31, 2012	$	26.98		0.11			4.92			5.03			(0.19	)		(2.37	)		(2.56	)
Year Ended December 31, 2011	$	28.56		(0.14	)		(1.27	)		(1.41	)		—			(0.17	)		(0.17	)
Year Ended December 31, 2010	$	23.19		(0.08	)		5.45			5.37			—			—			—

Notes to Financial Highlights

(b) Annualized.

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

(e) Class I shares commenced operations on September 27, 2010. Per share data and total return reflect activity from that date.

(f) Rounds to zero.

(g) Class R4 shares commenced operations on November 8, 2012. Per share data and total return reflect activity from that date.

(h) Class R5 shares commenced operations on November 8, 2012. Per share data and total return reflect activity from that date.

(i) Class Y shares commenced operations on November 8, 2012. Per share data and total return reflect activity from that date.

See accompanying notes to financial statements.

						Ratio to Average Net Assets									Supplemental Data
(Selected data for a share outstanding throughout each period)	Net Asset Value, End of Period		Total Return			Total gross expenses (a)			Total net expenses (a)			Net investment income (loss)			Portfolio turnover rate			Net assets, end of period (000s)
Class A
Six Months Ended June 30, 2015 (Unaudited)	$	30.38		7.14	%		1.34	%(b)		1.34	%(b)		(0.50	)%(b)		18	%	$	136,711
Year Ended December 31, 2014	$	29.13		3.35	%		1.33	%		1.33	%		(0.60	)%		12	%	$	148,089
Year Ended December 31, 2013	$	34.15		32.34	%		1.32	%		1.32	%		(0.46	)%		17	%	$	201,559
Year Ended December 31, 2012	$	28.21		18.67	%		1.32	%(c)		1.32	%(c)(d)		0.08	%		14	%	$	152,164
Year Ended December 31, 2011	$	25.94		(5.21	)%		1.30	%		1.30	%(d)		(0.78	)%		20	%	$	167,038
Year Ended December 31, 2010	$	27.54		22.78	%		1.30	%		1.30	%(d)		(0.64	)%		32	%	$	214,097
Class B
Six Months Ended June 30, 2015 (Unaudited)	$	26.07		6.45	%		2.52	%(b)		2.52	%(b)		(1.70	)%(b)		18	%	$	130
Year Ended December 31, 2014	$	25.27		2.37	%		2.26	%		2.26	%		(1.55	)%		12	%	$	234
Year Ended December 31, 2013	$	30.70		31.28	%		2.15	%		2.15	%		(1.33	)%		17	%	$	567
Year Ended December 31, 2012	$	25.81		17.87	%		1.99	%(c)		1.99	%(c)(d)		(0.71	)%		14	%	$	1,056
Year Ended December 31, 2011	$	23.98		(5.68	)%		1.92	%		1.92	%(d)		(1.42	)%		20	%	$	2,253
Year Ended December 31, 2010	$	25.60		21.96	%		1.98	%		1.98	%(d)		(1.37	)%		32	%	$	9,222
Class C
Six Months Ended June 30, 2015 (Unaudited)	$	25.84		6.76	%		2.01	%(b)		2.01	%(b)		(1.17	)%(b)		18	%	$	35,239
Year Ended December 31, 2014	$	24.98		2.67	%		2.00	%		2.00	%		(1.26	)%		12	%	$	36,476
Year Ended December 31, 2013	$	30.33		31.47	%		2.00	%		2.00	%		(1.14	)%		17	%	$	40,395
Year Ended December 31, 2012	$	25.49		17.82	%		2.05	%(c)		2.05	%(c)(d)		(0.61	)%		14	%	$	31,410
Year Ended December 31, 2011	$	23.72		(5.92	)%		2.05	%		2.05	%(d)		(1.53	)%		20	%	$	30,584
Year Ended December 31, 2010	$	25.39		21.83	%		2.08	%		2.08	%(d)		(1.41	)%		32	%	$	36,101
Class I
Six Months Ended June 30, 2015 (Unaudited)	$	32.65		7.34	%		0.93	%(b)		0.93	%(b)		(0.10	)%(b)		18	%	$	2
Year Ended December 31, 2014	$	31.19		3.80	%		0.88	%		0.88	%		(0.17	)%		12	%	$	2
Year Ended December 31, 2013	$	35.99		32.93	%		0.90	%		0.90	%		(0.04	)%		17	%	$	4
Year Ended December 31, 2012	$	29.47		19.10	%		0.96	%		0.96	%(d)		(0.33	)%		14	%	$	3
Year Ended December 31, 2011	$	27.00		(4.88	)%		0.94	%		0.94	%(d)		(0.47	)%		20	%	$	2,635
Year Ended December 31, 2010(e)	$	28.56		17.82	%		0.94	%(b)		0.94	%(b)(d)		(0.35	)%(b)		32	%	$	28,993
Class R4
Six Months Ended June 30, 2015 (Unaudited)	$	33.17		7.26	%		1.09	%(b)		1.09	%(b)		(0.22	)%(b)		18	%	$	12,551
Year Ended December 31, 2014	$	31.70		3.60	%		1.07	%		1.07	%		(0.32	)%		12	%	$	7,952
Year Ended December 31, 2013	$	36.55		32.80	%		1.00	%		1.00	%		0.01	%		17	%	$	6,441
Year Ended December 31, 2012(g)	$	29.92		8.06	%		1.14	%(b)(c)		1.14	%(b)(c)(d)		1.51	%(b)		14	%	$	15
Class R5
Six Months Ended June 30, 2015 (Unaudited)	$	33.20		7.32	%		1.00	%(b)		1.00	%(b)		(0.16	)%(b)		18	%	$	35,962
Year Ended December 31, 2014	$	31.71		3.68	%		0.99	%		0.99	%		(0.17	)%		12	%	$	36,689
Year Ended December 31, 2013	$	36.53		32.83	%		0.97	%		0.97	%		0.06	%		17	%	$	6,068
Year Ended December 31, 2012(h)	$	29.90		8.06	%		1.12	%(b)		1.12	%(b)(d)		1.53	%(b)		14	%	$	2
Class Y
Six Months Ended June 30, 2015 (Unaudited)	$	33.30		7.33	%		0.95	%(b)		0.95	%(b)		(0.11	)%(b)		18	%	$	36,734
Year Ended December 31, 2014	$	31.80		3.76	%		0.93	%		0.93	%		(0.19	)%		12	%	$	35,551
Year Ended December 31, 2013	$	36.59		32.89	%		0.93	%		0.93	%		0.07	%		17	%	$	48,479
Year Ended December 31, 2012(i)	$	29.93		8.07	%		1.04	%(b)		1.04	%(b)(d)		1.62	%(b)		14	%	$	2
Class Z
Six Months Ended June 30, 2015 (Unaudited)	$	32.45		7.25	%		1.09	%(b)		1.09	%(b)		(0.26	)%(b)		18	%	$	1,054,246
Year Ended December 31, 2014	$	31.03		3.61	%		1.08	%		1.08	%		(0.34	)%		12	%	$	1,132,223
Year Ended December 31, 2013	$	35.90		32.72	%		1.06	%		1.06	%		(0.20	)%		17	%	$	1,496,775
Year Ended December 31, 2012	$	29.45		18.98	%		1.07	%(c)		1.07	%(c)(d)		0.36	%		14	%	$	1,415,442
Year Ended December 31, 2011	$	26.98		(4.95	)%		1.00	%		1.00	%(d)		(0.48	)%		20	%	$	1,355,934
Year Ended December 31, 2010	$	28.56		23.16	%		1.01	%		1.01	%(d)		(0.34	)%		32	%	$	1,410,133

See accompanying notes to financial statements.

COLUMBIA ACORN FAMILY OF FUNDS

FINANCIAL HIGHLIGHTS, CONTINUED

Columbia Acorn International Select^SM

			Income from Investment Operations									Less Distributions to Shareholders
(Selected data for a share outstanding throughout each period)	Net Asset Value, Beginning of Period		Net investment income (loss)			Net realized and unrealized gain (loss)			Total from Investment Operations			Net investment income			Net realized gains			Total Distributions to Shareholders			Redemption fees added to paid in capital
Class A
Six Months Ended June 30, 2015 (Unaudited)	$	22.04		0.15			0.67			0.82			(0.10	)		—			(0.10	)		—
Year Ended December 31, 2014	$	26.91		0.29			(2.17	)		(1.88	)		(0.10	)		(2.89	)		(2.99	)		—
Year Ended December 31, 2013	$	25.61		0.29			3.29			3.58			(0.37	)		(1.91	)		(2.28	)		—
Year Ended December 31, 2012	$	24.26		0.39			4.92			5.31			(1.75	)		(2.21	)		(3.96	)		—
Year Ended December 31, 2011	$	28.01		0.18			(2.95	)		(2.77	)		(0.59	)		(0.39	)		(0.98	)		—
Year Ended December 31, 2010	$	23.39		0.08			4.84			4.92			(0.30	)		—			(0.30	)		0.00	(f)
Class B
Six Months Ended June 30, 2015 (Unaudited)	$	20.69		0.04			0.65			0.69			(0.01	)		—			(0.01	)		—
Year Ended December 31, 2014	$	25.53		0.10			(2.05	)		(1.95	)		—			(2.89	)		(2.89	)		—
Year Ended December 31, 2013	$	24.40		0.11			3.12			3.23			(0.19	)		(1.91	)		(2.10	)		—
Year Ended December 31, 2012	$	23.27		0.23			4.69			4.92			(1.58	)		(2.21	)		(3.79	)		—
Year Ended December 31, 2011	$	26.72		0.01			(2.82	)		(2.81	)		(0.25	)		(0.39	)		(0.64	)		—
Year Ended December 31, 2010	$	22.34		(0.06	)		4.62			4.56			(0.18	)		—			(0.18	)		0.00	(f)
Class C
Six Months Ended June 30, 2015 (Unaudited)	$	20.54		0.06			0.63			0.69			—			—			—			—
Year Ended December 31, 2014	$	25.39		0.07			(2.03	)		(1.96	)		—			(2.89	)		(2.89	)		—
Year Ended December 31, 2013	$	24.28		0.08			3.10			3.18			(0.16	)		(1.91	)		(2.07	)		—
Year Ended December 31, 2012	$	23.17		0.18			4.67			4.85			(1.53	)		(2.21	)		(3.74	)		—
Year Ended December 31, 2011	$	26.58		(0.04	)		(2.81	)		(2.85	)		(0.17	)		(0.39	)		(0.56	)		—
Year Ended December 31, 2010	$	22.21		(0.10	)		4.60			4.50			(0.13	)		—			(0.13	)		0.00	(f)
Class I
Six Months Ended June 30, 2015 (Unaudited)	$	22.29		0.19			0.68			0.87			(0.10	)		—			(0.10	)		—
Year Ended December 31, 2014	$	27.19		0.39			(2.20	)		(1.81	)		(0.20	)		(2.89	)		(3.09	)		—
Year Ended December 31, 2013	$	25.85		0.39			3.32			3.71			(0.46	)		(1.91	)		(2.37	)		—
Year Ended December 31, 2012	$	24.45		0.51			4.94			5.45			(1.84	)		(2.21	)		(4.05	)		—
Year Ended December 31, 2011	$	28.33		0.31			(2.97	)		(2.66	)		(0.83	)		(0.39	)		(1.22	)		—
Year Ended December 31, 2010(h)	$	26.11		0.03			2.19			2.22			—			—			—			—
Class R4
Six Months Ended June 30, 2015 (Unaudited)	$	22.45		0.19			0.68			0.87			(0.10	)		—			(0.10	)		—
Year Ended December 31, 2014	$	27.36		0.37			(2.22	)		(1.85	)		(0.17	)		(2.89	)		(3.06	)		—
Year Ended December 31, 2013	$	25.99		0.29			3.42			3.71			(0.43	)		(1.91	)		(2.34	)		—
Year Ended December 31, 2012(i)	$	29.98		(0.02	)		(0.09	)(j)		(0.11	)		(1.79	)		(2.09	)		(3.88	)		—
Class R5
Six Months Ended June 30, 2015 (Unaudited)	$	22.43		0.21			0.67			0.88			(0.10	)		—			(0.10	)		—
Year Ended December 31, 2014	$	27.34		0.36			(2.19	)		(1.83	)		(0.19	)		(2.89	)		(3.08	)		—
Year Ended December 31, 2013	$	25.98		0.38			3.35			3.73			(0.46	)		(1.91	)		(2.37	)		—
Year Ended December 31, 2012(k)	$	29.98		(0.02	)		(0.09	)(j)		(0.11	)		(1.80	)		(2.09	)		(3.89	)		—
Class Y
Six Months Ended June 30, 2015 (Unaudited)	$	22.42		0.20			0.68			0.88			(0.10	)		—			(0.10	)		—
Year Ended December 31, 2014	$	27.33		0.40			(2.21	)		(1.81	)		(0.21	)		(2.89	)		(3.10	)		—
Year Ended December 31, 2013	$	25.98		0.11			3.62			3.73			(0.47	)		(1.91	)		(2.38	)		—
Year Ended December 31, 2012(l)	$	29.99		(0.02	)		(0.09	)(j)		(0.11	)		(1.81	)		(2.09	)		(3.90	)		—
Class Z
Six Months Ended June 30, 2015 (Unaudited)	$	22.30		0.19			0.68			0.87			(0.10	)		—			(0.10	)		—
Year Ended December 31, 2014	$	27.20		0.38			(2.21	)		(1.83	)		(0.18	)		(2.89	)		(3.07	)		—
Year Ended December 31, 2013	$	25.86		0.37			3.33			3.70			(0.45	)		(1.91	)		(2.36	)		—
Year Ended December 31, 2012	$	24.46		0.49			4.95			5.44			(1.83	)		(2.21	)		(4.04	)		—
Year Ended December 31, 2011	$	28.33		0.29			(2.98	)		(2.69	)		(0.79	)		(0.39	)		(1.18	)		—
Year Ended December 31, 2010	$	23.64		0.18			4.89			5.07			(0.38	)		—			(0.38	)		0.00	(f)

Notes to Financial Highlights

(b) Annualized.

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

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

(f) Rounds to zero.

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

(h) Class I shares commenced operations on September 27, 2010. Per share data and total return reflect activity from that date.

(i) Class R4 shares commenced operations on November 8, 2012. Per share data and total return reflect activity from that date.

(j) Calculation of the net gain (loss) per share (both realized and unrealized) does not correlate to the aggregate realized and unrealized gain (loss) presented in the Statements of Operations due to the timing of subscriptions and redemptions of Fund shares in relation to fluctuations in the market value of the portfolio.

(k) Class R5 shares commenced operations on November 8, 2012. Per share data and total return reflect activity from that date.

(l) Class Y shares commenced operations on November 8, 2012. Per share data and total return reflect activity from that date.

See accompanying notes to financial statements.

100

									Ratio to Average Net Assets									Supplemental Data
(Selected data for a share outstanding throughout each period)	Increase from regulatory settlements			Net Asset Value, End of Period		Total Return			Total gross expenses (a)			Total net expenses (a)			Net investment income (loss)			Portfolio turnover rate			Net assets, end of period (000s)
Class A
Six Months Ended June 30, 2015 (Unaudited)		—		$	22.76		3.70	%		1.52	%(b)		1.52	%(b)		1.32	%(b)		29	%	$	43,965
Year Ended December 31, 2014		—		$	22.04		(7.06	)%		1.47	%		1.47	%		1.05	%		58	%	$	53,419
Year Ended December 31, 2013		—		$	26.91		14.42	%		1.47	%		1.47	%		1.08	%		72	%	$	73,911
Year Ended December 31, 2012		—		$	25.61		22.05	%		1.49	%(c)		1.49	%(c)(d)		1.43	%		63	%	$	74,167
Year Ended December 31, 2011		—		$	24.26		(10.11	)%		1.51	%		1.51	%(e)		0.66	%		44	%	$	56,350
Year Ended December 31, 2010		0.00	(f)	$	28.01		21.41	%		1.56	%		1.56	%(e)		0.33	%		42	%	$	71,668
Class B
Six Months Ended June 30, 2015 (Unaudited)		—		$	21.37		3.36	%(g)		2.29	%(b)		2.20	%(b)		0.38	%(b)		29	%	$	136
Year Ended December 31, 2014		—		$	20.69		(7.71	)%		2.11	%		2.11	%		0.39	%		58	%	$	355
Year Ended December 31, 2013		—		$	25.53		13.67	%		2.14	%		2.14	%		0.43	%		72	%	$	873
Year Ended December 31, 2012		—		$	24.40		21.29	%		2.11	%(c)		2.10	%(c)(d)		0.87	%		63	%	$	1,250
Year Ended December 31, 2011		—		$	23.27		(10.64	)%		2.14	%		2.14	%(e)		0.04	%		44	%	$	1,774
Year Ended December 31, 2010		0.00	(f)	$	26.72		20.63	%(g)		2.24	%		2.20	%(e)		(0.27	)%		42	%	$	3,030
Class C
Six Months Ended June 30, 2015 (Unaudited)		—		$	21.23		3.36	%		2.29	%(b)		2.29	%(b)		0.53	%(b)		29	%	$	7,250
Year Ended December 31, 2014		—		$	20.54		(7.80	)%		2.23	%		2.23	%		0.29	%		58	%	$	8,057
Year Ended December 31, 2013		—		$	25.39		13.52	%		2.26	%		2.26	%		0.32	%		72	%	$	10,311
Year Ended December 31, 2012		—		$	24.28		21.10	%		2.28	%(c)		2.27	%(c)(d)		0.67	%		63	%	$	9,786
Year Ended December 31, 2011		—		$	23.17		(10.81	)%		2.31	%		2.31	%(e)		(0.14	)%		44	%	$	8,704
Year Ended December 31, 2010		0.00	(f)	$	26.58		20.45	%		2.36	%		2.36	%(e)		(0.45	)%		42	%	$	11,885
Class I
Six Months Ended June 30, 2015 (Unaudited)		—		$	23.06		3.88	%		1.19	%(b)		1.19	%(b)		1.68	%(b)		29	%	$	2
Year Ended December 31, 2014		—		$	22.29		(6.72	)%		1.11	%		1.11	%		1.41	%		58	%	$	2
Year Ended December 31, 2013		—		$	27.19		14.82	%		1.13	%		1.13	%		1.43	%		72	%	$	3
Year Ended December 31, 2012		—		$	25.85		22.48	%		1.15	%		1.14	%(d)		1.84	%		63	%	$	2
Year Ended December 31, 2011		—		$	24.45		(9.68	)%		1.04	%		1.04	%(e)		1.12	%		44	%	$	2
Year Ended December 31, 2010(h)		—		$	28.33		8.50	%		1.14	%(b)		1.14	%(b)(e)		0.44	%(b)		42	%	$	3
Class R4
Six Months Ended June 30, 2015 (Unaudited)		—		$	23.22		3.86	%		1.25	%(b)		1.25	%(b)		1.66	%(b)		29	%	$	1,080
Year Ended December 31, 2014		—		$	22.45		(6.83	)%		1.21	%		1.21	%		1.33	%		58	%	$	974
Year Ended December 31, 2013		—		$	27.36		14.72	%		1.24	%		1.24	%		1.06	%		72	%	$	417
Year Ended December 31, 2012(i)		—		$	25.99		(0.27	)%		1.30	%(b)(c)		1.30	%(b)(c)(d)		(0.55	)%(b)		63	%	$	13
Class R5
Six Months Ended June 30, 2015 (Unaudited)		—		$	23.21		3.90	%		1.18	%(b)		1.18	%(b)		1.78	%(b)		29	%	$	3,485
Year Ended December 31, 2014		—		$	22.43		(6.77	)%		1.15	%		1.15	%		1.30	%		58	%	$	2,593
Year Ended December 31, 2013		—		$	27.34		14.80	%(g)		1.15	%		1.15	%		1.40	%		72	%	$	956
Year Ended December 31, 2012(k)		—		$	25.98		(0.27	)%		1.29	%(b)		1.28	%(b)(d)		(0.55	)%(b)		63	%	$	2
Class Y
Six Months Ended June 30, 2015 (Unaudited)		—		$	23.20		3.91	%		1.12	%(b)		1.12	%(b)		1.73	%(b)		29	%	$	10,763
Year Ended December 31, 2014		—		$	22.42		(6.71	)%		1.09	%		1.09	%		1.43	%		58	%	$	11,755
Year Ended December 31, 2013		—		$	27.33		14.82	%		1.09	%		1.09	%		0.40	%		72	%	$	13,318
Year Ended December 31, 2012(l)		—		$	25.98		(0.25	)%		1.21	%(b)		1.20	%(b)(d)		(0.48	)%(b)		63	%	$	2
Class Z
Six Months Ended June 30, 2015 (Unaudited)		—		$	23.07		3.88	%		1.22	%(b)		1.22	%(b)		1.62	%(b)		29	%	$	156,750
Year Ended December 31, 2014		—		$	22.30		(6.79	)%		1.17	%		1.17	%		1.36	%		58	%	$	175,764
Year Ended December 31, 2013		—		$	27.20		14.75	%		1.19	%		1.19	%		1.37	%		72	%	$	256,100
Year Ended December 31, 2012		—		$	25.86		22.42	%		1.20	%(c)		1.19	%(c)(d)		1.77	%		63	%	$	295,231
Year Ended December 31, 2011		—		$	24.46		(9.76	)%		1.14	%		1.14	%(e)		1.03	%		44	%	$	259,553
Year Ended December 31, 2010		0.00	(f)	$	28.33		21.89	%		1.16	%		1.16	%(e)		0.75	%		42	%	$	366,081

See accompanying notes to financial statements.

101

COLUMBIA ACORN FAMILY OF FUNDS

FINANCIAL HIGHLIGHTS, CONTINUED

Columbia Acorn Select^SM

			Income from Investment Operations												Less Distributions to Shareholders
(Selected data for a share outstanding throughout each period)	Net Asset Value, Beginning of Period		Net investment income (loss)			Net realized and unrealized gain (loss)			Reimbursement from affiliate			Total from Investment Operations			Net investment income			Net realized gains			Total Distributions to Shareholders
Class A
Six Months Ended June 30, 2015 (Unaudited)	$	21.03		(0.04	)		1.31			—			1.27			—			(1.78	)		(1.78	)
Year Ended December 31, 2014	$	25.57		(0.14	)		0.64			—			0.50			—			(5.04	)		(5.04	)
Year Ended December 31, 2013	$	24.72		(0.15	)		7.92			—			7.77			(0.07	)		(6.85	)		(6.92	)
Year Ended December 31, 2012	$	22.95		0.03			3.78			—			3.81			—			(2.04	)		(2.04	)
Year Ended December 31, 2011	$	27.94		(0.15	)		(4.46	)		—			(4.61	)		(0.38	)		—			(0.38	)
Year Ended December 31, 2010	$	22.81		(0.18	)		5.31			—			5.13			—			—			—
Class B
Six Months Ended June 30, 2015 (Unaudited)	$	18.03		(0.12	)		1.13			—			1.01			—			(1.78	)		(1.78	)
Year Ended December 31, 2014	$	22.81		(0.31	)		0.57			—			0.26			—			(5.04	)		(5.04	)
Year Ended December 31, 2013	$	22.75		(0.33	)		7.24			—			6.91			—			(6.85	)		(6.85	)
Year Ended December 31, 2012	$	21.40		(0.15	)		3.54			—			3.39			—			(2.04	)		(2.04	)
Year Ended December 31, 2011	$	26.06		(0.30	)		(4.13	)		—			(4.43	)		(0.23	)		—			(0.23	)
Year Ended December 31, 2010	$	21.41		(0.31	)		4.96			—			4.65			—			—			—
Class C
Six Months Ended June 30, 2015 (Unaudited)	$	17.69		(0.10	)		1.10			—			1.00			—			(1.78	)		(1.78	)
Year Ended December 31, 2014	$	22.46		(0.28	)		0.55			—			0.27			—			(5.04	)		(5.04	)
Year Ended December 31, 2013	$	22.48		(0.32	)		7.15			—			6.83			—			(6.85	)		(6.85	)
Year Ended December 31, 2012	$	21.20		(0.14	)		3.46			—			3.32			—			(2.04	)		(2.04	)
Year Ended December 31, 2011	$	25.83		(0.32	)		(4.12	)		—			(4.44	)		(0.19	)		—			(0.19	)
Year Ended December 31, 2010	$	21.25		(0.34	)		4.92			—			4.58			—			—			—
Class I
Six Months Ended June 30, 2015 (Unaudited)	$	22.38		0.00	(f)		1.40			—			1.40			—			(1.78	)		(1.78	)
Year Ended December 31, 2014	$	26.81		(0.05	)		0.66			—			0.61			—			(5.04	)		(5.04	)
Year Ended December 31, 2013	$	25.63		(0.06	)		8.25			—			8.19			(0.16	)		(6.85	)		(7.01	)
Year Ended December 31, 2012	$	23.65		0.23			3.79			—			4.02			—			(2.04	)		(2.04	)
Year Ended December 31, 2011	$	28.74		(0.03	)		(4.59	)		—			(4.62	)		(0.47	)		—			(0.47	)
Year Ended December 31, 2010(g)	$	24.74		0.01			3.99			—			4.00			—			—			—
Class R4
Six Months Ended June 30, 2015 (Unaudited)	$	22.75		(0.02	)		1.42			—			1.40			—			(1.78	)		(1.78	)
Year Ended December 31, 2014	$	27.20		(0.10	)		0.69			—			0.59			—			(5.04	)		(5.04	)
Year Ended December 31, 2013	$	25.92		(0.06	)		8.32			—			8.26			(0.13	)		(6.85	)		(6.98	)
Year Ended December 31, 2012(h)	$	25.91		0.00	(f)		1.52			—			1.52			—			(1.51	)		(1.51	)
Class R5
Six Months Ended June 30, 2015 (Unaudited)	$	22.78		(0.03	)		1.44			—			1.41			—			(1.78	)		(1.78	)
Year Ended December 31, 2014	$	27.20		(0.07	)		0.69			—			0.62			—			(5.04	)		(5.04	)
Year Ended December 31, 2013	$	25.93		(0.04	)		8.31			—			8.27			(0.15	)		(6.85	)		(7.00	)
Year Ended December 31, 2012(i)	$	25.91		0.00	(f)		1.53			—			1.53			—			(1.51	)		(1.51	)
Class Y
Six Months Ended June 30, 2015 (Unaudited)	$	22.86		(0.00	)(f)		1.42			—			1.42			—			(1.78	)		(1.78	)
Year Ended December 31, 2014	$	27.27		(0.06	)		0.69			—			0.63			—			(5.04	)		(5.04	)
Year Ended December 31, 2013	$	25.98		(0.03	)		8.34			—			8.31			(0.17	)		(6.85	)		(7.02	)
Year Ended December 31, 2012(j)	$	25.96		0.01			1.52			—			1.53			—			(1.51	)		(1.51	)
Class Z
Six Months Ended June 30, 2015 (Unaudited)	$	22.28		(0.02	)		1.39			—			1.37			—			(1.78	)		(1.78	)
Year Ended December 31, 2014	$	26.72		(0.08	)		0.68			—			0.60			—			(5.04	)		(5.04	)
Year Ended December 31, 2013	$	25.57		(0.07	)		8.21			—			8.14			(0.14	)		(6.85	)		(6.99	)
Year Ended December 31, 2012	$	23.62		0.11			3.88			—			3.99			—			(2.04	)		(2.04	)
Year Ended December 31, 2011	$	28.73		(0.07	)		(4.58	)		0.00	(f)		(4.65	)		(0.46	)		—			(0.46	)
Year Ended December 31, 2010	$	23.38		(0.10	)		5.45			—			5.35			—			—			—

Notes to Financial Highlights

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

(d) Ratios include line of credit interest expense which is less than 0.01%.

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

(f) Rounds to zero.

(g) Class I shares commenced operations on September 27, 2010. Per share data and total return reflect activity from that date.

(h) Class R4 shares commenced operations on November 8, 2012. Per share data and total return reflect activity from that date.

(i) Class R5 shares commenced operations on November 8, 2012. Per share data and total return reflect activity from that date.

(j) Class Y shares commenced operations on November 8, 2012. Per share data and total return reflect activity from that date.

(k) During the year ended December 31, 2011, the Fund received a reimbursement from an affiliate. Had the Fund not received this payment, the total return would have been lower by 0.01%.

See accompanying notes to financial statements.

102

						Ratio to Average Net Assets									Supplemental Data
(Selected data for a share outstanding throughout each period)	Net Asset Value, End of Period		Total Return			Total gross expenses (a)			Total net expenses (a)			Net investment income (loss)			Portfolio turnover rate			Net assets, end of period (000s)
Class A
Six Months Ended June 30, 2015 (Unaudited)	$	20.52		5.96	%(b)		1.34	%(c)		1.27	%(c)		(0.42	)%(c)		33	%	$	244,592
Year Ended December 31, 2014	$	21.03		2.17	%		1.32	%		1.32	%		(0.58	)%		17	%	$	264,234
Year Ended December 31, 2013	$	25.57		33.77	%		1.31	%(d)		1.31	%(d)		(0.54	)%		20	%	$	333,193
Year Ended December 31, 2012	$	24.72		16.87	%		1.31	%(d)		1.31	%(d)(e)		0.13	%		15	%	$	271,628
Year Ended December 31, 2011	$	22.95		(16.65	)%		1.28	%		1.28	%(e)		(0.57	)%		21	%	$	340,325
Year Ended December 31, 2010	$	27.94		22.49	%		1.28	%		1.28	%(e)		(0.73	)%		28	%	$	555,263
Class B
Six Months Ended June 30, 2015 (Unaudited)	$	17.26		5.50	%(b)		2.42	%(c)		2.10	%(c)		(1.30	)%(c)		33	%	$	533
Year Ended December 31, 2014	$	18.03		1.35	%(b)		2.14	%		2.10	%		(1.40	)%		17	%	$	1,014
Year Ended December 31, 2013	$	22.81		32.81	%(b)		2.05	%(d)		2.03	%(d)		(1.32	)%		20	%	$	2,938
Year Ended December 31, 2012	$	22.75		16.11	%		1.91	%(d)		1.90	%(d)(e)		(0.62	)%		15	%	$	9,938
Year Ended December 31, 2011	$	21.40		(17.11	)%		1.88	%		1.88	%(e)		(1.21	)%		21	%	$	26,126
Year Ended December 31, 2010	$	26.06		21.72	%		1.92	%		1.92	%(e)		(1.39	)%		28	%	$	72,203
Class C
Six Months Ended June 30, 2015 (Unaudited)	$	16.91		5.55	%(b)		2.07	%(c)		2.00	%(c)		(1.15	)%(c)		33	%	$	43,848
Year Ended December 31, 2014	$	17.69		1.42	%		2.04	%		2.04	%		(1.30	)%		17	%	$	48,591
Year Ended December 31, 2013	$	22.46		32.85	%		2.04	%(d)		2.04	%(d)		(1.28	)%		20	%	$	61,537
Year Ended December 31, 2012	$	22.48		15.93	%		2.07	%(d)		2.06	%(d)(e)		(0.59	)%		15	%	$	57,309
Year Ended December 31, 2011	$	21.20		(17.27	)%		2.05	%		2.05	%(e)		(1.34	)%		21	%	$	62,887
Year Ended December 31, 2010	$	25.83		21.55	%		2.07	%		2.07	%(e)		(1.52	)%		28	%	$	98,445
Class I
Six Months Ended June 30, 2015 (Unaudited)	$	22.00		6.19	%(b)		0.98	%(c)		0.88	%(c)		0.02	%(c)		33	%	$	29,505
Year Ended December 31, 2014	$	22.38		2.49	%		0.94	%		0.94	%		(0.20	)%		17	%	$	18,718
Year Ended December 31, 2013	$	26.81		34.31	%		0.94	%(d)		0.94	%(d)		(0.21	)%		20	%	$	13,660
Year Ended December 31, 2012	$	25.63		17.26	%		0.96	%(d)		0.95	%(d)(e)		0.89	%		15	%	$	39,054
Year Ended December 31, 2011	$	23.65		(16.25	)%		0.92	%		0.92	%(e)		(0.12	)%		21	%	$	10,944
Year Ended December 31, 2010(g)	$	28.74		16.17	%		0.91	%(c)		0.91	%(c)(e)		0.18	%(c)		28	%	$	7,832
Class R4
Six Months Ended June 30, 2015 (Unaudited)	$	22.37		6.08	%(b)		1.11	%(c)		1.04	%(c)		(0.18	)%(c)		33	%	$	1,282
Year Ended December 31, 2014	$	22.75		2.39	%		1.12	%		1.12	%		(0.37	)%		17	%	$	1,193
Year Ended December 31, 2013	$	27.20		34.16	%		1.02	%(d)		1.02	%(d)		(0.20	)%		20	%	$	1,383
Year Ended December 31, 2012(h)	$	25.92		5.92	%		1.07	%(c)		1.06	%(c)(e)		0.02	%(c)		15	%	$	15
Class R5
Six Months Ended June 30, 2015 (Unaudited)	$	22.41		6.12	%(b)		1.01	%(c)		0.97	%(c)		(0.28	)%(c)		33	%	$	2,302
Year Ended December 31, 2014	$	22.78		2.50	%		1.00	%		1.00	%		(0.26	)%		17	%	$	10,697
Year Ended December 31, 2013	$	27.20		34.21	%		0.97	%(d)		0.97	%(d)		(0.13	)%		20	%	$	11,996
Year Ended December 31, 2012(i)	$	25.93		5.96	%		0.99	%(c)		0.99	%(c)(e)		0.08	%(c)		15	%	$	3
Class Y
Six Months Ended June 30, 2015 (Unaudited)	$	22.50		6.14	%(b)		0.97	%(c)		0.90	%(c)		(0.02	)%(c)		33	%	$	4,135
Year Ended December 31, 2014	$	22.86		2.53	%		0.95	%		0.95	%		(0.22	)%		17	%	$	3,644
Year Ended December 31, 2013	$	27.27		34.30	%		0.93	%(d)		0.93	%(d)		(0.09	)%		20	%	$	4,847
Year Ended December 31, 2012(j)	$	25.98		5.94	%		0.92	%(c)		0.92	%(c)(e)		0.15	%(c)		15	%	$	3
Class Z
Six Months Ended June 30, 2015 (Unaudited)	$	21.87		6.07	%(b)		1.06	%(c)		1.00	%(c)		(0.15	)%(c)		33	%	$	278,552
Year Ended December 31, 2014	$	22.28		2.47	%		1.04	%		1.04	%		(0.30	)%		17	%	$	318,487
Year Ended December 31, 2013	$	26.72		34.16	%		1.02	%(d)		1.02	%(d)		(0.26	)%		20	%	$	431,990
Year Ended December 31, 2012	$	25.57		17.15	%		1.03	%(d)		1.03	%(d)(e)		0.40	%		15	%	$	587,678
Year Ended December 31, 2011	$	23.62		(16.37	)%(k)		0.97	%		0.97	%(e)		(0.28	)%		21	%	$	850,338
Year Ended December 31, 2010	$	28.73		22.88	%		0.97	%		0.97	%(e)		(0.41	)%		28	%	$	1,549,112

See accompanying notes to financial statements.

103

COLUMBIA ACORN FAMILY OF FUNDS

FINANCIAL HIGHLIGHTS, CONTINUED

Columbia Thermostat Fund^SM

			Income from Investment Operations						Less Distributions to Shareholders
(Selected data for a share outstanding throughout each period)	Net Asset Value, Beginning of Period		Net investment income		Net realized and unrealized gain		Total from Investment Operations		Net investment income			Net realized gains			Total Distributions to Shareholders
Class A
Six Months Ended June 30, 2015 (Unaudited)	$	14.86		0.13		0.03		0.16		(0.02	)		(0.28	)		(0.30	)
Year Ended December 31, 2014	$	14.58		0.28		0.49		0.77		(0.28	)		(0.21	)		(0.49	)
Year Ended December 31, 2013	$	14.29		0.29		1.00		1.29		(0.25	)		(0.75	)		(1.00	)
Year Ended December 31, 2012	$	12.82		0.32		1.39		1.71		(0.24	)		—			(0.24	)
Year Ended December 31, 2011	$	12.58		0.28		0.30		0.58		(0.34	)		—			(0.34	)
Year Ended December 31, 2010	$	10.90		0.19		1.67		1.86		(0.18	)		—			(0.18	)
Class B
Six Months Ended June 30, 2015 (Unaudited)	$	14.97		0.09		0.03		0.12		(0.02	)		(0.28	)		(0.30	)
Year Ended December 31, 2014	$	14.68		0.21		0.50		0.71		(0.21	)		(0.21	)		(0.42	)
Year Ended December 31, 2013	$	14.39		0.19		1.03		1.22		(0.18	)		(0.75	)		(0.93	)
Year Ended December 31, 2012	$	12.91		0.20		1.45		1.65		(0.17	)		—			(0.17	)
Year Ended December 31, 2011	$	12.64		0.15		0.38		0.53		(0.26	)		—			(0.26	)
Year Ended December 31, 2010	$	10.93		0.13		1.67		1.80		(0.09	)		—			(0.09	)
Class C
Six Months Ended June 30, 2015 (Unaudited)	$	14.96		0.08		0.03		0.11		(0.02	)		(0.28	)		(0.30	)
Year Ended December 31, 2014	$	14.68		0.17		0.49		0.66		(0.17	)		(0.21	)		(0.38	)
Year Ended December 31, 2013	$	14.39		0.18		1.00		1.18		(0.14	)		(0.75	)		(0.89	)
Year Ended December 31, 2012	$	12.91		0.22		1.39		1.61		(0.13	)		—			(0.13	)
Year Ended December 31, 2011	$	12.62		0.18		0.31		0.49		(0.20	)		—			(0.20	)
Year Ended December 31, 2010	$	10.91		0.10		1.68		1.78		(0.07	)		—			(0.07	)
Class R4
Six Months Ended June 30, 2015 (Unaudited)	$	14.74		0.15		0.03		0.18		(0.02	)		(0.28	)		(0.30	)
Year Ended December 31, 2014	$	14.46		0.32		0.49		0.81		(0.32	)		(0.21	)		(0.53	)
Year Ended December 31, 2013	$	14.19		0.36		0.95		1.31		(0.29	)		(0.75	)		(1.04	)
Year Ended December 31, 2012(e)	$	14.08		0.09		0.28		0.37		(0.26	)		—			(0.26	)
Class R5
Six Months Ended June 30, 2015 (Unaudited)	$	14.75		0.15		0.03		0.18		(0.02	)		(0.28	)		(0.30	)
Year Ended December 31, 2014	$	14.47		0.31		0.50		0.81		(0.32	)		(0.21	)		(0.53	)
Year Ended December 31, 2013	$	14.19		0.37		0.96		1.33		(0.30	)		(0.75	)		(1.05	)
Year Ended December 31, 2012(f)	$	14.08		0.09		0.27		0.36		(0.25	)		—			(0.25	)
Class Y
Six Months Ended June 30, 2015 (Unaudited)	$	14.74		0.15		0.03		0.18		(0.02	)		(0.28	)		(0.30	)
Year Ended December 31, 2014	$	14.46		0.32		0.50		0.82		(0.33	)		(0.21	)		(0.54	)
Year Ended December 31, 2013	$	14.18		0.33		1.01		1.34		(0.31	)		(0.75	)		(1.06	)
Year Ended December 31, 2012(g)	$	14.08		0.09		0.27		0.36		(0.26	)		—			(0.26	)
Class Z
Six Months Ended June 30, 2015 (Unaudited)	$	14.67		0.15		0.03		0.18		(0.02	)		(0.28	)		(0.30	)
Year Ended December 31, 2014	$	14.40		0.32		0.48		0.80		(0.32	)		(0.21	)		(0.53	)
Year Ended December 31, 2013	$	14.13		0.32		0.99		1.31		(0.29	)		(0.75	)		(1.04	)
Year Ended December 31, 2012	$	12.67		0.34		1.39		1.73		(0.27	)		—			(0.27	)
Year Ended December 31, 2011	$	12.44		0.31		0.29		0.60		(0.37	)		—			(0.37	)
Year Ended December 31, 2010	$	10.80		0.21		1.66		1.87		(0.23	)		—			(0.23	)

Notes to Financial Highlights

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

(b) In addition to the fees and expenses that the Fund bears directly, the Fund indirectly bears a pro rata share of the fees and expenses of the underlying funds in which the Fund invests, if any. Such indirect expenses are not included in the Fund's reported expense ratios.

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

(e) Class R4 shares commenced operations on November 8, 2012. Per share data and total return reflect activity from that date.

(f) Class R5 shares commenced operations on November 8, 2012. Per share data and total return reflect activity from that date.

(g) Class Y shares commenced operations on November 8, 2012. Per share data and total return reflect activity from that date.

See accompanying notes to financial statements.

104

						Ratio to Average Net Assets									Supplemental Data
(Selected data for a share outstanding throughout each period)	Net Asset Value, End of Period		Total Return (a)			Total gross expenses (b)			Total net expenses (b)			Net investment income			Portfolio turnover rate			Net assets, end of period (000s)
Class A
Six Months Ended June 30, 2015 (Unaudited)	$	14.72		1.08	%		0.52	%(c)		0.50	%(c)		1.75	%(c)		24	%	$	427,618
Year Ended December 31, 2014	$	14.86		5.30	%		0.51	%		0.50	%		1.88	%		95	%	$	450,258
Year Ended December 31, 2013	$	14.58		9.07	%		0.52	%		0.50	%		1.91	%		92	%	$	513,293
Year Ended December 31, 2012	$	14.29		13.34	%		0.58	%		0.50	%(d)		2.28	%		109	%	$	323,750
Year Ended December 31, 2011	$	12.82		4.62	%		0.67	%		0.50	%(d)		2.17	%		130	%	$	79,744
Year Ended December 31, 2010	$	12.58		17.28	%		0.72	%		0.50	%(d)		1.64	%		118	%	$	44,527
Class B
Six Months Ended June 30, 2015 (Unaudited)	$	14.79		0.81	%		1.18	%(c)		1.00	%(c)		1.25	%(c)		24	%	$	937
Year Ended December 31, 2014	$	14.97		4.83	%		1.15	%		1.00	%		1.39	%		95	%	$	1,231
Year Ended December 31, 2013	$	14.68		8.49	%		1.15	%		1.00	%		1.29	%		92	%	$	2,263
Year Ended December 31, 2012	$	14.39		12.78	%		1.16	%		1.00	%(d)		1.47	%		109	%	$	4,480
Year Ended December 31, 2011	$	12.91		4.19	%		1.23	%		1.00	%(d)		1.18	%		130	%	$	11,318
Year Ended December 31, 2010	$	12.64		16.64	%		1.28	%		1.00	%(d)		1.10	%		118	%	$	28,752
Class C
Six Months Ended June 30, 2015 (Unaudited)	$	14.77		0.74	%		1.27	%(c)		1.25	%(c)		1.00	%(c)		24	%	$	380,771
Year Ended December 31, 2014	$	14.96		4.50	%		1.26	%		1.25	%		1.14	%		95	%	$	404,456
Year Ended December 31, 2013	$	14.68		8.23	%		1.27	%		1.25	%		1.16	%		92	%	$	430,173
Year Ended December 31, 2012	$	14.39		12.52	%		1.32	%		1.25	%(d)		1.56	%		109	%	$	253,641
Year Ended December 31, 2011	$	12.91		3.87	%		1.43	%		1.25	%(d)		1.40	%		130	%	$	33,378
Year Ended December 31, 2010	$	12.62		16.43	%		1.49	%		1.25	%(d)		0.88	%		118	%	$	21,866
Class R4
Six Months Ended June 30, 2015 (Unaudited)	$	14.62		1.23	%		0.27	%(c)		0.25	%(c)		2.00	%(c)		24	%	$	21,959
Year Ended December 31, 2014	$	14.74		5.61	%		0.26	%		0.25	%		2.14	%		95	%	$	23,412
Year Ended December 31, 2013	$	14.46		9.26	%		0.28	%		0.25	%		2.39	%		92	%	$	14,651
Year Ended December 31, 2012(e)	$	14.19		2.60	%		0.42	%(c)		0.25	%(c)(d)		4.59	%(c)		109	%	$	15
Class R5
Six Months Ended June 30, 2015 (Unaudited)	$	14.63		1.23	%		0.25	%(c)		0.23	%(c)		2.02	%(c)		24	%	$	4,749
Year Ended December 31, 2014	$	14.75		5.62	%		0.24	%		0.23	%		2.11	%		95	%	$	3,536
Year Ended December 31, 2013	$	14.47		9.35	%		0.25	%		0.23	%		2.44	%		92	%	$	979
Year Ended December 31, 2012(f)	$	14.19		2.58	%		0.35	%(c)		0.27	%(c)(d)		4.60	%(c)		109	%	$	3
Class Y
Six Months Ended June 30, 2015 (Unaudited)	$	14.62		1.23	%		0.19	%(c)		0.18	%(c)		2.08	%(c)		24	%	$	342
Year Ended December 31, 2014	$	14.74		5.68	%		0.19	%		0.18	%		2.19	%		95	%	$	401
Year Ended December 31, 2013	$	14.46		9.46	%		0.14	%		0.14	%		2.23	%		92	%	$	3
Year Ended December 31, 2012(g)	$	14.18		2.55	%		0.30	%(c)		0.22	%(c)(d)		4.63	%(c)		109	%	$	3
Class Z
Six Months Ended June 30, 2015 (Unaudited)	$	14.55		1.23	%		0.25	%(c)		0.24	%(c)		2.01	%(c)		24	%	$	341,926
Year Ended December 31, 2014	$	14.67		5.57	%		0.25	%		0.24	%		2.16	%		95	%	$	377,119
Year Ended December 31, 2013	$	14.40		9.30	%		0.26	%		0.25	%		2.14	%		92	%	$	375,444
Year Ended December 31, 2012	$	14.13		13.69	%		0.30	%		0.25	%(d)		2.48	%		109	%	$	292,732
Year Ended December 31, 2011	$	12.67		4.85	%		0.34	%		0.25	%(d)		2.43	%		130	%	$	65,167
Year Ended December 31, 2010	$	12.44		17.58	%		0.37	%		0.25	%(d)		1.87	%		118	%	$	36,130

See accompanying notes to financial statements.

105

COLUMBIA ACORN FAMILY OF FUNDS

FINANCIAL HIGHLIGHTS, CONTINUED

Columbia Acorn Emerging Markets Fund^SM

			Income from Investment Operations									Less Distributions to Shareholders
(Selected data for a share outstanding throughout each period)	Net Asset Value, Beginning of Period		Net investment income (loss)			Net realized and unrealized gain (loss)			Total from Investment Operations			Net investment income			Total Distributions to Shareholders			Net Asset Value, End of Period
Class A
Six Months Ended June 30, 2015 (Unaudited)	$	12.72		0.07			(0.45	)		(0.38	)		—			—		$	12.34
Year Ended December 31, 2014	$	13.37		0.06			(0.63	)		(0.57	)		(0.08	)		(0.08	)	$	12.72
Year Ended December 31, 2013	$	12.04		0.07			1.34			1.41			(0.08	)		(0.08	)	$	13.37
Year Ended December 31, 2012	$	9.26		0.08			2.78			2.86			(0.08	)		(0.08	)	$	12.04
Year Ended December 31, 2011(e)	$	10.00		(0.00	)(f)		(0.74	)		(0.74	)		—			—		$	9.26
Class C
Six Months Ended June 30, 2015 (Unaudited)	$	12.65		0.02			(0.44	)		(0.42	)		—			—		$	12.23
Year Ended December 31, 2014	$	13.32		(0.05	)		(0.62	)		(0.67	)		—			—		$	12.65
Year Ended December 31, 2013	$	12.01		(0.03	)		1.34			1.31			—			—		$	13.32
Year Ended December 31, 2012	$	9.24		(0.02	)		2.79			2.77			—			—		$	12.01
Year Ended December 31, 2011(h)	$	10.00		(0.02	)		(0.74	)		(0.76	)		—			—		$	9.24
Class I
Six Months Ended June 30, 2015 (Unaudited)	$	12.75		0.09			(0.45	)		(0.36	)		—			—		$	12.39
Year Ended December 31, 2014	$	13.41		0.06			(0.60	)		(0.54	)		(0.12	)		(0.12	)	$	12.75
Year Ended December 31, 2013	$	12.08		0.08			1.37			1.45			(0.12	)		(0.12	)	$	13.41
Year Ended December 31, 2012	$	9.29		0.11			2.80			2.91			(0.12	)		(0.12	)	$	12.08
Year Ended December 31, 2011(i)	$	10.00		0.01			(0.72	)		(0.71	)		—			—		$	9.29
Class R4
Six Months Ended June 30, 2015 (Unaudited)	$	12.83		0.09			(0.46	)		(0.37	)		—			—		$	12.46
Year Ended December 31, 2014	$	13.49		0.09			(0.63	)		(0.54	)		(0.12	)		(0.12	)	$	12.83
Year Ended December 31, 2013	$	12.14		0.12			1.35			1.47			(0.12	)		(0.12	)	$	13.49
Year Ended December 31, 2012(j)	$	11.44		(0.01	)		0.81			0.80			(0.10	)		(0.10	)	$	12.14
Class R5
Six Months Ended June 30, 2015 (Unaudited)	$	12.82		0.09			(0.46	)		(0.37	)		—			—		$	12.45
Year Ended December 31, 2014	$	13.48		0.10			(0.64	)		(0.54	)		(0.12	)		(0.12	)	$	12.82
Year Ended December 31, 2013	$	12.14		0.12			1.34			1.46			(0.12	)		(0.12	)	$	13.48
Year Ended December 31, 2012(k)	$	11.44		(0.00	)(f)		0.81			0.81			(0.11	)		(0.11	)	$	12.14
Class Y
Six Months Ended June 30, 2015 (Unaudited)	$	12.71		0.10			(0.46	)		(0.36	)		—			—		$	12.35
Year Ended December 31, 2014	$	13.36		0.09			(0.62	)		(0.53	)		(0.12	)		(0.12	)	$	12.71
Year Ended December 31, 2013(l)	$	12.22		0.07			1.20			1.27			(0.13	)		(0.13	)	$	13.36
Class Z
Six Months Ended June 30, 2015 (Unaudited)	$	12.74		0.09			(0.45	)		(0.36	)		—			—		$	12.38
Year Ended December 31, 2014	$	13.40		0.08			(0.63	)		(0.55	)		(0.11	)		(0.11	)	$	12.74
Year Ended December 31, 2013	$	12.07		0.11			1.33			1.44			(0.11	)		(0.11	)	$	13.40
Year Ended December 31, 2012	$	9.28		0.12			2.79			2.91			(0.12	)		(0.12	)	$	12.07
Year Ended December 31, 2011(m)	$	10.00		0.01			(0.73	)		(0.72	)		—			—		$	9.28

Notes to Financial Highlights

(a) Annualized.

(b) In addition to the fees and expenses that the Fund bears directly, the Fund indirectly bears a pro rata share of the fees and expenses of any other funds in which it invests, if any. Such indirect expenses are not included in the Fund's reported expense ratios.

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

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

(e) Class A shares commenced operations on August 19, 2011. Per share data and total return reflect activity from that date.

(f) Rounds to zero.

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

(h) Class C shares commenced operations on August 19, 2011. Per share data and total return reflect activity from that date.

(i) Class I shares commenced operations on August 19, 2011. Per share data and total return reflect activity from that date.

(j) Class R4 shares commenced operations on November 8, 2012. Per share data and total return reflect activity from that date.

(k) Class R5 shares commenced operations on November 8, 2012. Per share data and total return reflect activity from that date.

(l) Class Y shares commenced operations on June 13, 2013. Per share data and total return reflect activity from that date.

(m) Class Z shares commenced operations on August 19, 2011. Per share data and total return reflect activity from that date.

See accompanying notes to financial statements.

106

				Ratio to Average Net Assets									Supplemental Data
(Selected data for a share outstanding throughout each period)	Total Return			Total gross expenses			Total net expenses			Net investment income (loss)			Portfolio turnover rate			Net assets, end of period (000s)
Class A
Six Months Ended June 30, 2015 (Unaudited)		(2.99	)%		1.62	%(a)(b)		1.62	%(a)(b)		1.08	%(a)		33	%	$	138,930
Year Ended December 31, 2014		(4.28	)%		1.56	%(b)		1.56	%(b)		0.42	%		45	%	$	160,969
Year Ended December 31, 2013		11.73	%(c)		1.80	%(b)		1.76	%(b)		0.52	%		36	%	$	177,158
Year Ended December 31, 2012		30.86	%(c)		6.42	%(b)		1.77	%(b)(d)		0.77	%		30	%	$	3,103
Year Ended December 31, 2011(e)		(7.40	)%(c)		20.13	%(a)		1.85	%(a)(g)		(0.01	)%(a)		9	%	$	332
Class C
Six Months Ended June 30, 2015 (Unaudited)		(3.32	)%		2.38	%(a)(b)		2.38	%(a)(b)		0.33	%(a)		33	%	$	34,754
Year Ended December 31, 2014		(5.03	)%		2.33	%(b)		2.33	%(b)		(0.36	)%		45	%	$	41,208
Year Ended December 31, 2013		10.91	%(c)		2.55	%(b)		2.51	%(b)		(0.23	)%		36	%	$	32,636
Year Ended December 31, 2012		29.98	%(c)		7.18	%(b)		2.56	%(b)(d)		(0.15	)%		30	%	$	615
Year Ended December 31, 2011(h)		(7.60	)%(c)		25.06	%(a)		2.60	%(a)(g)		(0.68	)%(a)		9	%	$	127
Class I
Six Months Ended June 30, 2015 (Unaudited)		(2.82	)%		1.29	%(a)(b)		1.29	%(a)(b)		1.46	%(a)		33	%	$	2
Year Ended December 31, 2014		(4.01	)%		1.22	%(b)		1.22	%(b)		0.44	%		45	%	$	3
Year Ended December 31, 2013		12.06	%(c)		1.73	%(b)		1.39	%(b)		0.65	%		36	%	$	7
Year Ended December 31, 2012		31.39	%(c)		6.18	%(b)		1.41	%(b)(d)		1.05	%		30	%	$	6
Year Ended December 31, 2011(i)		(7.10	)%(c)		19.31	%(a)		1.41	%(a)(g)		0.17	%(a)		9	%	$	5
Class R4
Six Months Ended June 30, 2015 (Unaudited)		(2.88	)%		1.33	%(a)(b)		1.33	%(a)(b)		1.41	%(a)		33	%	$	13,812
Year Ended December 31, 2014		(4.03	)%		1.28	%(b)		1.28	%(b)		0.66	%		45	%	$	15,467
Year Ended December 31, 2013		12.13	%(c)		1.44	%(b)		1.44	%(b)		0.92	%		36	%	$	13,583
Year Ended December 31, 2012(j)		7.04	%(c)		5.86	%(a)(b)		1.54	%(a)(b)(d)		(0.31	)%(a)		30	%	$	16
Class R5
Six Months Ended June 30, 2015 (Unaudited)		(2.89	)%		1.31	%(a)(b)		1.31	%(a)(b)		1.43	%(a)		33	%	$	18,725
Year Ended December 31, 2014		(4.02	)%		1.26	%(b)		1.26	%(b)		0.72	%		45	%	$	19,632
Year Ended December 31, 2013		12.07	%(c)		1.42	%(b)		1.42	%(b)		0.94	%		36	%	$	13,625
Year Ended December 31, 2012(k)		7.11	%(c)		5.81	%(a)(b)		1.46	%(a)(b)(d)		(0.22	)%(a)		30	%	$	3
Class Y
Six Months Ended June 30, 2015 (Unaudited)		(2.83	)%		1.23	%(a)(b)		1.23	%(a)(b)		1.52	%(a)		33	%	$	2
Year Ended December 31, 2014		(3.95	)%		1.22	%(b)		1.22	%(b)		0.68	%		45	%	$	2
Year Ended December 31, 2013(l)		10.43	%(c)		1.36	%(a)(b)		1.36	%(a)(b)		0.97	%(a)		36	%	$	3
Class Z
Six Months Ended June 30, 2015 (Unaudited)		(2.83	)%		1.37	%(a)(b)		1.37	%(a)(b)		1.35	%(a)		33	%	$	210,646
Year Ended December 31, 2014		(4.12	)%		1.33	%(b)		1.33	%(b)		0.62	%		45	%	$	245,053
Year Ended December 31, 2013		11.92	%(c)		1.58	%(b)		1.54	%(b)		0.89	%		36	%	$	177,693
Year Ended December 31, 2012		31.35	%(c)		6.15	%(b)		1.46	%(b)(d)		1.07	%		30	%	$	6,846
Year Ended December 31, 2011(m)		(7.20	)%(c)		19.52	%(a)		1.46	%(a)(g)		0.15	%(a)		9	%	$	2,765

See accompanying notes to financial statements.

107

COLUMBIA ACORN FAMILY OF FUNDS

FINANCIAL HIGHLIGHTS, CONTINUED

Columbia Acorn European Fund^SM

			Income from Investment Operations									Less Distributions to Shareholders
(Selected data for a share outstanding throughout each period)	Net Asset Value, Beginning of Period		Net investment income (loss)			Net realized and unrealized gain (loss)			Total from Investment Operations			Net investment income			Net realized gains			Total Distributions to Shareholders
Class A
Six Months Ended June 30, 2015 (Unaudited)	$	14.34		0.15			0.81			0.96			(0.07	)		—			(0.07	)
Year Ended December 31, 2014	$	15.68		0.13			(1.34	)		(1.21	)		(0.05	)		(0.08	)		(0.13	)
Year Ended December 31, 2013	$	11.76		(0.02	)		3.97			3.95			(0.01	)		(0.02	)		(0.03	)
Year Ended December 31, 2012	$	9.43		0.03			2.37			2.40			(0.07	)		(0.00	)(d)		(0.07	)
Year Ended December 31, 2011(f)	$	10.00		(0.03	)		(0.46	)		(0.49	)		(0.06	)		(0.02	)		(0.08	)
Class C
Six Months Ended June 30, 2015 (Unaudited)	$	14.16		0.09			0.80			0.89			—			—			—
Year Ended December 31, 2014	$	15.54		(0.01	)		(1.29	)		(1.30	)		—			(0.08	)		(0.08	)
Year Ended December 31, 2013	$	11.73		(0.15	)		3.98			3.83			—			(0.02	)		(0.02	)
Year Ended December 31, 2012	$	9.44		(0.15	)		2.46			2.31			(0.02	)		(0.00	)(d)		(0.02	)
Year Ended December 31, 2011(h)	$	10.00		(0.06	)		(0.45	)		(0.51	)		(0.03	)		(0.02	)		(0.05	)
Class I
Six Months Ended June 30, 2015 (Unaudited)	$	14.33		0.16			0.82			0.98			(0.07	)		—			(0.07	)
Year Ended December 31, 2014	$	15.67		0.11			(1.27	)		(1.16	)		(0.10	)		(0.08	)		(0.18	)
Year Ended December 31, 2013	$	11.75		0.12			3.88			4.00			(0.06	)		(0.02	)		(0.08	)
Year Ended December 31, 2012	$	9.43		0.10			2.32			2.42			(0.10	)		(0.00	)(d)		(0.10	)
Year Ended December 31, 2011(i)	$	10.00		(0.02	)		(0.46	)		(0.48	)		(0.07	)		(0.02	)		(0.09	)
Class R4
Six Months Ended June 30, 2015 (Unaudited)	$	14.40		0.20			0.78			0.98			(0.07	)		—			(0.07	)
Year Ended December 31, 2014(j)	$	15.85		(0.02	)		(1.34	)		(1.36	)		(0.09	)		—			(0.09	)
Class R5
Six Months Ended June 30, 2015 (Unaudited)	$	14.47		0.16			0.83			0.99			(0.07	)		—			(0.07	)
Year Ended December 31, 2014	$	15.82		0.14			(1.32	)		(1.18	)		(0.09	)		(0.08	)		(0.17	)
Year Ended December 31, 2013	$	11.86		(0.04	)		4.06			4.02			(0.04	)		(0.02	)		(0.06	)
Year Ended December 31, 2012(k)	$	11.19		(0.02	)		0.77			0.75			(0.08	)		—			(0.08	)
Class Z
Six Months Ended June 30, 2015 (Unaudited)	$	14.34		0.18			0.80			0.98			(0.07	)		—			(0.07	)
Year Ended December 31, 2014	$	15.68		0.15			(1.32	)		(1.17	)		(0.09	)		(0.08	)		(0.17	)
Year Ended December 31, 2013	$	11.76		0.11			3.88			3.99			(0.05	)		(0.02	)		(0.07	)
Year Ended December 31, 2012	$	9.44		0.08			2.34			2.42			(0.10	)		(0.00	)(d)		(0.10	)
Year Ended December 31, 2011(l)	$	10.00		(0.02	)		(0.46	)		(0.48	)		(0.06	)		(0.02	)		(0.08	)

Notes to Financial Highlights

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

(d) Rounds to zero.

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

(f) Class A shares commenced operations on August 19, 2011. Per share data and total return reflect activity from that date.

(g) The benefits derived from custody fees paid indirectly had an impact of 0.02%.

(h) Class C shares commenced operations on August 19, 2011. Per share data and total return reflect activity from that date.

(i) Class I shares commenced operations on August 19, 2011. Per share data and total return reflect activity from that date.

(j) Class R4 shares commenced operations on June 25, 2014. Per share data and total return reflect activity from that date.

(k) Class R5 shares commenced operations on November 8, 2012. Per share data and total return reflect activity from that date.

(l) Class Z shares commenced operations on August 19, 2011. Per share data and total return reflect activity from that date.

See accompanying notes to financial statements.

108

						Ratio to Average Net Assets									Supplemental Data
(Selected data for a share outstanding throughout each period)	Net Asset Value, End of Period		Total Return (a)			Total gross expenses			Total net expenses			Net investment income (loss)			Portfolio turnover rate			Net assets, end of period (000s)
Class A
Six Months Ended June 30, 2015 (Unaudited)	$	15.23		6.66	%		2.03	%(b)(c)		1.75	%(b)(c)		2.06	%(c)		15	%	$	34,321
Year Ended December 31, 2014	$	14.34		(7.77	)%		2.05	%(b)		1.75	%(b)		0.86	%		74	%	$	21,101
Year Ended December 31, 2013	$	15.68		33.64	%		3.33	%(b)		1.74	%(b)		(0.11	)%		42	%	$	19,078
Year Ended December 31, 2012	$	11.76		25.46	%		12.35	%(b)		1.61	%(b)(e)		0.23	%		37	%	$	453
Year Ended December 31, 2011(f)	$	9.43		(4.97	)%		33.59	%(c)		1.75	%(c)(g)		(0.84	)%(c)		17	%	$	154
Class C
Six Months Ended June 30, 2015 (Unaudited)	$	15.05		6.29	%		2.80	%(b)(c)		2.50	%(b)(c)		1.18	%(c)		15	%	$	6,711
Year Ended December 31, 2014	$	14.16		(8.44	)%		2.84	%(b)		2.50	%(b)		(0.10	)%		74	%	$	5,096
Year Ended December 31, 2013	$	15.54		32.63	%		4.19	%(b)		2.50	%(b)		(1.10	)%		42	%	$	1,400
Year Ended December 31, 2012	$	11.73		24.46	%		12.83	%(b)		2.32	%(b)(e)		(1.33	)%		37	%	$	89
Year Ended December 31, 2011(h)	$	9.44		(5.14	)%		35.79	%(c)		2.50	%(c)(g)		(1.66	)%(c)		17	%	$	5
Class I
Six Months Ended June 30, 2015 (Unaudited)	$	15.24		6.80	%		1.71	%(b)(c)		1.45	%(b)(c)		2.13	%(c)		15	%	$	3
Year Ended December 31, 2014	$	14.33		(7.49	)%		1.71	%(b)		1.46	%(b)		0.74	%		74	%	$	2
Year Ended December 31, 2013	$	15.67		34.06	%		3.99	%(b)		1.41	%(b)		0.88	%		42	%	$	8
Year Ended December 31, 2012	$	11.75		25.71	%		12.05	%(b)		1.31	%(b)(e)		0.94	%		37	%	$	6
Year Ended December 31, 2011(i)	$	9.43		(4.81	)%		30.00	%(c)		1.31	%(c)(g)		(0.47	)%(c)		17	%	$	5
Class R4
Six Months Ended June 30, 2015 (Unaudited)	$	15.31		6.77	%		1.77	%(b)(c)		1.50	%(b)(c)		2.61	%(c)		15	%	$	597
Year Ended December 31, 2014(j)	$	14.40		(8.60	)%		1.87	%(b)(c)		1.50	%(b)(c)		(0.30	)%(c)		74	%	$	302
Class R5
Six Months Ended June 30, 2015 (Unaudited)	$	15.39		6.81	%		1.73	%(b)(c)		1.50	%(b)(c)		2.10	%(c)		15	%	$	1,858
Year Ended December 31, 2014	$	14.47		(7.54	)%		1.75	%(b)		1.52	%(b)		0.92	%		74	%	$	1,633
Year Ended December 31, 2013	$	15.82		33.97	%		2.76	%(b)		1.51	%(b)		(0.29	)%		42	%	$	1,891
Year Ended December 31, 2012(k)	$	11.86		6.70	%		14.07	%(b)(c)		1.36	%(b)(c)(e)		(1.07	)%(c)		37	%	$	3
Class Z
Six Months Ended June 30, 2015 (Unaudited)	$	15.25		6.80	%		1.75	%(b)(c)		1.50	%(b)(c)		2.37	%(c)		15	%	$	12,994
Year Ended December 31, 2014	$	14.34		(7.52	)%		1.79	%(b)		1.50	%(b)		0.97	%		74	%	$	8,499
Year Ended December 31, 2013	$	15.68		33.98	%		3.98	%(b)		1.45	%(b)		0.83	%		42	%	$	4,407
Year Ended December 31, 2012	$	11.76		25.66	%		12.07	%(b)		1.33	%(b)(e)		0.76	%		37	%	$	2,727
Year Ended December 31, 2011(l)	$	9.44		(4.78	)%		30.26	%(c)		1.37	%(c)(g)		(0.52	)%(c)		17	%	$	1,516

See accompanying notes to financial statements.

109

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, Columbia Thermostat Fund, Columbia Acorn Emerging Markets Fund and Columbia Acorn European Fund (each a Fund and collectively, the Funds) are each a series of Columbia Acorn Trust (the Trust). The Trust is registered under the Investment Company Act of 1940, as amended (the 1940 Act), as an open-end management investment company organized as a Massachusetts business trust. The investment objective of each Fund is to seek long-term capital appreciation.

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

Each Fund may issue an unlimited number of shares. Columbia Acorn Fund, Columbia Acorn USA, Columbia Acorn International Select and Columbia Acorn Select each currently offers Class A, Class B, Class C, Class I, Class R4, Class R5, Class Y and Class Z shares. Columbia Acorn International currently offers Class A, Class B, Class C, Class I, Class R, Class R4, Class R5, Class Y and Class Z shares. Columbia Thermostat Fund currently offers Class A, Class B, Class C, Class R4, Class R5, Class Y and Class Z shares. Columbia Acorn Emerging Markets Fund currently offers Class A, Class C, Class I, Class R4, Class R5, Class Y and Class Z shares. Columbia Acorn European Fund currently offers Class A, Class C, Class I, Class R4, Class R5 and Class Z shares. Effective February 29, 2008, the Funds generally no longer accept investments by new or existing investors in the Funds' Class B shares, except in connection with the reinvestment of any dividend and/or capital gain distributions in Class B shares of the Funds and exchanges by existing Class B shareholders of certain other funds within the Columbia Acorn Family of Funds.

Class A shares are sold with a front-end sales charge. Columbia Acorn Emerging Markets Fund is closed to most new investors and new accounts with certain exceptions. Class A shares bought without an initial sales charge in accounts aggregating $1 million to $50 million at the time of purchase

are subject to a 1.00% contingent deferred sales charge (CDSC) if the shares are redeemed within 12 months of purchase, and a 0.50% CDSC if the shares are redeemed more than 12, but less than 18, months after purchase, with certain limited exceptions.

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

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

Class I, Class R, Class R4, Class R5 and Class Y shares are offered at net asset value. There are certain restrictions on who may purchase these share classes.

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

Investment income, realized and unrealized gains and losses, and certain fund-level expenses are allocated pro rata on the basis of the relative net assets of all classes, except that each class bears certain expenses specific to that class such as distribution services, transfer agent fees, and certain other class specific expenses. Differences in class expenses may result in payment of different dividend distributions for each class. All of the Funds' share classes have equal rights with respect to voting, subject to Fund or class-specific matters.

2. Summary of Significant Accounting Policies

>Basis of preparation

Each Fund is an investment company that applies the accounting and reporting guidance in the Financial Accounting Standards Board (FASB) Accounting Standards Codification Topic 946, Financial Services – Investment Companies (ASC 946). The financial statements are prepared in accordance with U.S. generally accepted accounting principles (GAAP) which requires management to make certain estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of income and expenses during the reporting period. Actual results could differ from those estimates.

The following is a summary of significant accounting policies followed by the Funds in the preparation of their financial statements.

110

>Security valuation

Securities of the Funds are valued at market value or, if a market quotation for a security is not readily available or is deemed not to be reliable because of events or circumstances that have occurred between the market quotation and the time as of which the security is to be valued, the security is valued at a fair value determined in good faith under consistently applied procedures established by the Board of Trustees (the Board). With respect to Columbia Thermostat Fund, investments in underlying funds are valued at their net asset values as reported by the underlying funds. A security traded on a securities exchange or in an over-the-counter market in which transaction prices are reported is valued at the last sales price at the time of valuation. A security traded principally on NASDAQ is valued at the NASDAQ official closing price. Exchange traded funds are valued at their closing net asset value as reported on the applicable exchange.

Short-term investments maturing in 60 days or less are valued at amortized cost, which approximates market value.

Forward foreign currency exchange contracts are marked-to-market based upon foreign currency exchange rates provided by a pricing service.

The Trust has retained an independent statistical fair value pricing service that employs a systematic methodology to assist in the fair valuation process for securities principally traded in a foreign market in order to adjust for possible changes in value that may occur between the close of the foreign exchange and the time as of which the securities are to be valued. If a security is valued at fair value, that value may be different from the last quoted market price for the security. A security for which there is no reported sale on the valuation date is valued at the mean of the latest bid and ask quotations.

>Foreign currency translations

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

>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 Fund 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.

>Derivative instruments

Columbia Acorn Fund invested in futures contracts and Columbia Acorn International Select invested in forward foreign currency exchange contracts on a limited basis during the six months ended June 30, 2015, as detailed below. Derivatives may involve various risks, including the potential inability of the counterparty to fulfill its obligation under the terms of the contract, the potential for an illiquid secondary market (making it difficult for the Fund to sell, including at favorable prices) and the potential for market movements which may expose the Fund to gains or losses in excess of the amount shown in the Statements of Assets and Liabilities.

For financial reporting purposes, the Funds do not offset derivative assets and derivative liabilities that are subject to netting arrangements in the Statements of Assets and Liabilities.

>Forward foreign currency exchange contracts

Forward foreign currency exchange contracts are agreements between two parties to buy and sell a currency at a set price on a future date. Columbia Acorn International Select utilized forward foreign currency exchange contracts to hedge the currency exposure associated with some or all of the Fund's securities. These instruments may be used for other purposes in future periods. The Fund's use of forward foreign currency exchange contracts was not material to the net assets of the Fund.

The values of forward foreign currency exchange contracts fluctuate with changes in foreign currency exchange rates. Changes in the value of these contracts are recorded as unrealized appreciation or depreciation until the contract is exercised or has expired. The Fund will realize a gain or loss when the forward foreign currency exchange contract is closed or expires.

The use of forward foreign currency exchange contracts does not eliminate fluctuations in the prices of the Fund's portfolio securities. The risks of forward foreign currency exchange contracts include movement in the values of the foreign currencies relative to the U.S. dollar (or other foreign currencies) and

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COLUMBIA ACORN FAMILY OF FUNDS

NOTES TO FINANCIAL STATEMENTS (UNAUDITED), CONTINUED

the possibility that counterparties will not complete their contractual obligations, which may be in excess of the amount reflected, if any, in the Statements of Assets and Liabilities.

>Futures contracts

Futures contracts are exchange traded and represent commitments for the future purchase or sale of an asset at a specified price on a specified date. Columbia Acorn Fund bought and sold futures contracts to maintain appropriate equity market exposure while keeping sufficient cash to accommodate daily redemptions. These instruments may be used for other purposes in future periods. Upon entering into futures contracts, the Fund bears risks that it may not achieve the anticipated benefits of the futures contracts and may realize a loss. Additional risks include counterparty credit risk, the possibility of an illiquid market, and that a change in the value of the contract or option may not correlate with changes in the value of the underlying asset. The Fund's use of futures contracts was not material to the net assets of the Fund.

Upon entering into a futures contract, the Fund pledges cash or securities with the broker in an amount sufficient to meet the initial margin requirement. The initial margin deposit must be maintained at an established level over the life of the contract. Cash deposited as initial margin is recorded in the Statements of Assets and Liabilities as margin deposits. Securities deposited as initial margin are designated in the Statement of Investments. Subsequent payments (variation margin) are made or received by the Fund each day. The variation margin payments are equal to the daily change in the contract value and are recorded as variation margin receivable or payable and are offset in unrealized gains or losses. The Fund recognizes a realized gain or loss when the contract is closed or expires. Futures contracts involve, to varying degrees, risk of loss in excess of the variation margin disclosed in the Statements of Assets and Liabilities.

>Effects of derivative transactions in the financial statements

The following tables are intended to provide additional information about the effect of derivatives on the financial statements of Columbia Acorn Fund and Columbia Acorn International Select including: the fair value of derivatives by risk category and the location of those fair values in the Statements of Assets and Liabilities; and the impact of derivative transactions over the period in the Statements of Operations, including realized gains or losses and unrealized gains or losses. The derivative schedules following the Statement of Investments

present additional information regarding derivative instruments outstanding at the end of the period, if any.

Columbia Acorn Fund

At June 30, 2015, the Fund had no outstanding derivatives.

The following table indicates the effect of derivative instruments (not considered to be hedging instruments for accounting disclosure purposes) in the Statements of Operations for the six months ended June 30, 2015:

Amount of Realized Gain (Loss) on
Derivatives Recognized in Income

Risk Exposure Category				Futures Contracts
Equity risk				$	2,900,917

The following table provides a summary of the average outstanding volume by derivative instrument for the six months ended June 30, 2015:

Derivative Instrument				Average notional amounts*
Futures contracts – Short				$	—

* Based on the ending quarterly outstanding amounts for the six months ended June 30, 2015. While there was no notional amount of futures contracts outstanding at any quarter end, the Fund did enter into futures contracts during the six months; the gain (loss) associated with this activity is presented in the Statements of Operations.

Columbia Acorn International Select

The following table provides a summary of the fair value of derivative instruments (not considered to be hedging instruments for accounting disclosure purposes) at June 30, 2015:

	Liability Derivatives
Risk Exposure Category	Statements of Assets and Liabilities Location	Fair Value ($)
Foreign exchange risk	Unrealized depreciation on forward foreign currency exchange contracts	$	237,682

Amount of Realized Gain (Loss) on
Derivatives Recognized in Income

Risk Exposure Category				Forward Foreign Currency Exchange Contracts ($)
Foreign exchange risk					291,763

Change in Unrealized Appreciation (Depreciation)
on Derivatives Recognized in Income

Risk Exposure Category				Forward Foreign Currency Exchange Contracts ($)
Foreign exchange risk					(140,501	)

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The following table provides a summary of the average outstanding volume by derivative instrument for the six months ended June 30, 2015:

Derivative Instrument				Average unrealized appreciation($)*				Average unrealized depreciation($)*
Forward foreign currency exchange contracts					—				(165,158	)

* Based on the ending quarterly outstanding amounts for the six months ended June 30, 2015.

>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 may receive distributions from holdings in equity securities, exchange-traded funds (ETFs), other regulated investment companies (RICs), and real estate investment trusts (REITs), which report information on the tax character of their distributions annually. These distributions are allocated to dividend income, capital gain and return of capital based on actual information reported. Return of capital is recorded as a reduction of the cost basis of securities held. If the Funds no longer own the applicable securities, return of capital is recorded as a realized gain. With respect to REITs, to the extent actual information has not yet been reported, estimates for return of capital may be made by the Funds' management. Management's estimates are subsequently adjusted when the actual character of the distributions is disclosed by the REITs, which could result in a proportionate change in return of capital to shareholders.

>Fund share valuation

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

>Securities lending

Each Fund, except Columbia Thermostat Fund, may lend securities up to one-third of the value of its total assets to certain approved brokers, dealers and other financial institutions to earn additional income. The Funds retain the benefits of owning the securities, including the economic equivalent of dividends or interest generated by the security. The Funds also receive a fee for the loan. The Funds have the ability to recall the loans at any time and could do so in order to vote proxies or to sell the loaned securities. Each loan is collateralized by cash that exceeds the value of the securities on loan. The market value of the loaned securities is determined daily at the close of business of a Fund and any additional required collateral is delivered to the Fund on the next business day. The Funds have elected to invest the cash collateral in the Dreyfus Government Cash Management Fund. The income earned from the securities lending program is paid to each Fund, net of any fees remitted to Goldman Sachs Agency Lending, the Funds' lending agent, and net of any borrower rebates. The Investment Manager does not retain any fees earned by the lending program. Generally, in the event of borrower default, a Fund has the right to use the collateral to offset any losses incurred. In the event a Fund is delayed or prevented from exercising its right to dispose of the collateral, there may be a potential loss to the Fund. Some of these losses may be indemnified by the lending agent. The Funds bear the risk of loss with respect to the investment of collateral. The net securities lending income earned as of June 30, 2015 by each Fund is included in the Statements of Operations.

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COLUMBIA ACORN FAMILY OF FUNDS

NOTES TO FINANCIAL STATEMENTS (UNAUDITED), CONTINUED

>Offsetting of Assets and Liabilities

The following table presents each Fund's gross and net amount of assets and liabilities available for offset under netting agreements and under a securities lending agreement as well as the related collateral received by each Fund as of June 30, 2015:

	Columbia Acorn Fund			Columbia Acorn International			Columbia Acorn USA			Columbia Acorn International Select						Columbia Acorn Select			Columbia Acorn Emerging Markets Fund			Columbia Acorn European Fund
	Goldman Sachs & Co.			Goldman Sachs & Co.			Goldman Sachs & Co.			Goldman Sachs & Co.			Morgan Stanley			Goldman Sachs & Co.			Goldman Sachs & Co.			Goldman Sachs & Co.
Liabilities:
Forward foreign currency exchange contracts	$	—		$	—		$	—		$	—		$	237,682		$	—		$	—		$	—
Securities loaned		205,638,386			186,393,214			53,302,525			8,381,123			—			14,060,046			2,703,540			1,790,781
Total Liabilities		205,638,386			186,393,214			53,302,525			8,381,123			237,682			14,060,046			2,703,540			1,790,781
Total Financial and Derivative Net Assets		(205,638,386	)		(186,393,214	)		(53,302,525	)		(8,381,123	)		(237,682	)		(14,060,046	)		(2,703,540	)		(1,790,781	)
Financial Instruments		205,238,253			178,244,535			53,095,035			7,925,539			—			13,779,499			2,610,061			1,540,884
Net Amount^(a)	$	(400,133	)	$	(8,148,679	)	$	(207,490	)	$	(455,584	)	$	(237,682	)	$	(280,547	)	$	(93,479	)	$	(249,897	)

^(a) Represents the net amount due from/ (to) counterparties in the event of default.

>Federal income taxes

It is each Fund's policy to comply with the provisions of the Internal Revenue Code available to regulated investment companies and, in the manner provided therein, distribute substantially all their taxable income, as well as any net realized gain on sales of investments and foreign currency transactions reportable for federal income tax purposes. Columbia Thermostat Fund distributes all of its taxable income, as well as any net realized gain on sales of portfolio fund shares and any distributions of net realized gains received by the Fund from its portfolio funds, reportable for federal income tax purposes. Accordingly, the Funds paid no federal income taxes and no federal income tax provision was required.

>Foreign capital gains taxes

Realized gains in certain countries may be subject to foreign taxes at the fund level. The Funds accrue for such foreign taxes on realized and unrealized gains at the appropriate rate for each jurisdiction. The amount, if any, is disclosed as a liability on the Statements of Assets and Liabilities.

>Distributions to shareholders

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

>Indemnification

In the normal course of business, the Trust on behalf of the Funds enters into contracts that contain a variety of representations and warranties and that provide general indemnities. A Fund's maximum exposure under these arrangements is unknown, as this would involve future claims against the Fund.

Also, under the Trust's organizational documents, the trustees and officers of the Trust are indemnified against certain liabilities that may arise out of their duties to the Trust. However, based on experience, the Funds expect the risk of loss due to these warranties and indemnities to be remote.

>Recent Accounting Pronouncement

Transfers and Servicing (Topic 860), Repurchase-to-Maturity Transactions, Repurchase Financings, and Disclosures

In June 2014, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2014-11, Transfers and Servicing (Topic 860), Repurchase-to-Maturity Transactions, Repurchase Financings, and Disclosures. ASU No. 2014-11 changes the accounting for transactions accounted for as secured borrowings and expands disclosure requirements related to securities lending and similar transactions. The disclosure requirements are effective for annual periods beginning after December 15, 2014, and for interim periods beginning after March 15, 2015. At this time, management is evaluating the implications of this guidance and the impact it will have on the financial statement amounts and footnote disclosures, if any.

3. Federal Tax Information

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

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The following capital loss carryforward, determined as of December 31, 2014, 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
	2015		2016		No Expiration Short-Term		Total
Columbia Acorn International	$	2,521,892	$	30,456,700	$	—	$	32,978,592
Columbia Acorn Emerging Markets Fund		—		—		14,671,234		14,671,234
Columbia Acorn European Fund		—		—		2,338,404		2,338,404

Under current tax rules, Regulated Investment Companies can elect to treat certain late-year ordinary losses incurred and post-October capital losses (capital losses realized after October 31) as arising on the first day of the following taxable year. The Funds have elected to treat the following late-year ordinary losses and post-October capital losses at December 31, 2014, as arising on January 1, 2015:

Fund	Late-Year Ordinary Losses		Post-October Capital Losses
Columbia Acorn International Select	$	—	$	8,767,586
Columbia Acorn Emerging Markets Fund		533,398		—

Management of the Funds has concluded that there are no significant uncertain tax positions in any Fund that would require recognition in the financial statements. However, management's conclusion may be subject to review and adjustment at a later date based on factors including, but not limited to, new tax laws, regulations, and administrative interpretations (including relevant court decisions). Generally, the Funds' federal tax returns for the prior three fiscal years remain subject to examination by the Internal Revenue Service.

4. Transactions With Affiliates

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

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

Columbia Acorn Fund

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

Columbia Acorn International

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

Columbia Acorn USA

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

Columbia Acorn International Select

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

Columbia Acorn Select

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

Columbia Thermostat Fund

				Annual Fee Rate
All Average Daily Net Assets					0.10	%

Columbia Acorn Emerging Markets Fund

Average Daily Net Assets	Annual Fee Rate
Up to $100 million		1.25	%
$100 million to $500 million		1.00	%
$500 million and over		0.80	%

Columbia Acorn European Fund

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

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COLUMBIA ACORN FAMILY OF FUNDS

NOTES TO FINANCIAL STATEMENTS (UNAUDITED), CONTINUED

Effective May 1, 2015, CWAM has contractually agreed to waive 0.20% of the advisory fee otherwise payable to it by Columbia Acorn Select through April 30, 2016. When determining whether the Fund's total expenses exceed the voluntary expense cap described below, the Fund's net advisory fee, reflecting application of the 0.20% waiver, will be used to calculate the Fund's total expenses. This arrangement may only be modified or amended with approval from all parties to the arrangement, including the Fund and CWAM.

For the six months ended June 30, 2015, the annualized effective investment advisory fee rates (net of the advisory fee waiver for Columbia Acorn Select) were as follows:

Fund
Columbia Acorn Fund	0.64	%
Columbia Acorn International	0.76	%
Columbia Acorn USA	0.87	%
Columbia Acorn International Select	0.94	%
Columbia Acorn Select	0.78	%
Columbia Thermostat Fund	0.10	%
Columbia Acorn Emerging Markets Fund	1.05	%
Columbia Acorn European Fund	1.19	%

>Expense limits

Columbia Management Investment Services Corp. (CMIS), a wholly owned subsidiary of Ameriprise Financial, has voluntarily agreed to waive a portion of the total annual Fund operating expenses attributable to transfer agency fees incurred by Class A, Class B and Class C shares of Columbia Acorn International such that the Fund's total annual Fund operating expenses will be reduced by 0.04%, 0.03% and 0.02% for Class A, Class B and Class C shares of the Fund, respectively.

Effective May 1, 2015, CWAM has voluntarily agreed to reimburse expenses so that the Funds' ordinary operating expenses (excluding transaction costs and certain other investment-related expenses, interest and fees on borrowings and expenses associated with each Fund's investments in other investment companies, if any) after giving effect to any balance credits or overdraft charges from the Funds' custodian, do not exceed the following annual rates as a percentage of each class' average daily net assets:

Fund	Class A			Class B			Class C			Class I			Class R4			Class R5			Class Y			Class Z
Columbia Acorn International Select		1.70	%		2.20	%		2.45	%		1.37	%		1.45	%		1.42	%		1.37	%		1.45	%
Columbia Acorn Select		1.60	%		2.10	%		2.35	%		1.25	%		1.35	%		1.30	%		1.25	%		1.35	%

These arrangements may be modified or terminated by either the Funds or CWAM on 30 days notice.

Through April 30, 2015, CWAM voluntarily agreed to reimburse expenses so that the Funds' ordinary operating expenses (excluding transaction costs and certain other investment-related expenses, interest and fees on borrowings and expenses associated with each Fund's investments in other investment companies, if any) after giving effect to any balance credits or overdraft charges from the Funds' custodian, do not exceed the following annual rates as a percentage of each class' average daily net assets:

Fund	Class A			Class B			Class C			Class I			Class R4			Class R5			Class Y			Class Z
Columbia Acorn International Select		1.70	%		2.20	%		2.45	%		1.37	%		1.45	%		1.42	%		1.37	%		1.45	%
Columbia Acorn Select		1.60	%		2.10	%		2.35	%		1.22	%		1.35	%		1.27	%		1.22	%		1.35	%

Effective May 1, 2015, CWAM has contractually agreed to waive fees and/or reimburse expenses through April 30, 2016, so that the Funds' ordinary operating expenses (excluding transaction costs and certain other investment-related expenses, interest and fees on borrowings and expenses associated with each Fund's investments in other investment companies, if any, and in the case of Columbia Thermostat Fund its underlying portfolio funds), do not exceed the following annual rates as a percentage of each class' average daily net assets:

Fund	Class A			Class B			Class C			Class I			Class R4			Class R5			Class Y			Class Z
Columbia Thermostat Fund		0.50	%		1.00	%		1.25	%		—	%		0.25	%		0.24	%		0.19	%		0.25	%
Columbia Acorn Emerging Markets Fund		1.85	%		—	%		2.60	%		1.48	%		1.60	%		1.53	%		1.48	%		1.60	%
Columbia Acorn European Fund		1.75	%		—	%		2.50	%		1.41	%		1.50	%		1.46	%		—	%		1.50	%

There is no guarantee that these agreements will continue thereafter.

116

Through April 30, 2015, CWAM contractually waived fees and/or reimburse expenses so that the Funds' ordinary operating expenses (excluding transaction costs and certain other investment-related expenses, interest and fees on borrowings and expenses associated with each Fund's investments in other investment companies, if any, and in the case of Columbia Thermostat Fund its underlying portfolio funds), did not exceed the following annual rates as a percentage of each class' average daily net assets:

Fund	Class A			Class B			Class C			Class I			Class R4			Class R5			Class Y			Class Z
Columbia Thermostat Fund		0.50	%		1.00	%		1.25	%		—	%		0.25	%		0.23	%		0.18	%		0.25	%
Columbia Acorn Emerging Markets Fund		1.85	%		—	%		2.60	%		1.46	%		1.60	%		1.51	%		1.46	%		1.60	%
Columbia Acorn European Fund		1.75	%		—	%		2.50	%		1.47	%		1.50	%*		1.52	%		—	%		1.50	%

* Effective June 25, 2014 (the commencement of operations of Columbia Acorn European Fund Class R4 shares) through April 30, 2015.

Expenses waived and/or reimbursed by CWAM and its affiliates for the six months ended June 30, 2015, were as follows:

Fund	Expenses Reimbursed
Columbia Acorn International	$	205,545
Columbia Acorn International Select		116
Columbia Acorn Select		208,875
Columbia Thermostat Fund		100,577
Columbia Acorn European Fund		60,916

CWAM is contractually entitled to recoup from each of Columbia Acorn Emerging Markets Fund and Columbia Acorn European Fund any fees waived and/or expenses reimbursed with respect to any share class offered by Columbia Acorn Emerging Markets Fund and Columbia Acorn European Fund for a one year period following the date of such fee waiver and/or reimbursement, if such recovery does not cause the ordinary operating expenses of the Fund (excluding transaction costs and certain other investment-related expenses, interest and fees on borrowings and expenses associated with the Fund's investment in other investment companies, if any) to exceed the annual rates set forth above, or to exceed such annual rate as may be in place at the time of the recoupment, whichever is less. For the six months ended June 30, 2015, there was no recoupment of fees.

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

Columbia Acorn Trust

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

For the six months ended June 30, 2015, the annualized effective administration fee rate was 0.04% of each Fund's average daily net assets. CWAM has delegated to Columbia Management responsibility to provide certain sub-administrative services to the Funds.

CMID, a wholly owned subsidiary of Ameriprise Financial, is the distributor of the Funds.

Sales charges, including front-end and CDSCs, received by the Distributor for distributing each Fund's shares for the six months ended June 30, 2015 are as follows:

	Underwriting Discounts		CDSCs
(Unaudited)	Class A		Class A		Class B		Class C
Columbia Acorn Fund	$	338,769	$	4,549	$	288	$	14,428
Columbia Acorn International		250,175		160		421		3,933
Columbia Acorn USA		25,606		7		—		302
Columbia Acorn International Select		17,130		—		—		270
Columbia Acorn Select		19,682		7		72		470
Columbia Thermostat Fund		428,213		477		—		15,940
Columbia Acorn Emerging Markets Fund		28,505		2,520		—		4,369
Columbia Acorn European Fund		122,786		—		—		1,038

Each Fund has adopted a distribution and service plan which requires it to pay CMID a monthly service fee equal to 0.25% annually of the average daily net assets attributable to Class A, Class B and Class C shares and a monthly distribution fee equal to 0.50%, 0.75% and 0.50%, annually, of the average daily net assets attributable to Class B, Class C and Class R shares, respectively. CMID receives no compensation with respect to Class R4, Class R5, Class Y and Class Z shares.

CMIS is the transfer agent of the Funds. CMIS receives monthly account-based service fees based on the number of open Fund accounts. Each Fund pays CMIS a monthly fee at the annual rate of $20.00 per open account. Subject to certain limitations, the Funds reimburse payments made by CMIS to financial intermediaries for the shareholder services that the intermediaries provide, in amounts that vary by share class and with the type of intermediary and type of shareholder services provided.

The Transfer Agent also receives compensation from fees for various shareholder services and reimbursements for

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COLUMBIA ACORN FAMILY OF FUNDS

NOTES TO FINANCIAL STATEMENTS (UNAUDITED), CONTINUED

certain out-of-pocket fees. Total transfer agency fees for Class R5 shares are subject to an annual limitation of not more than 0.05% of the average daily net assets attributable to

Class R5 shares. Class I shares and Class Y shares do not pay transfer agency fees.

For the six months ended June 30, 2015, the Funds' annualized effective transfer agency fee rates as a percentage of average daily net assets of each class were as follows:

Fund	Class A			Class B			Class C			Class R			Class R4			Class R5			Class Z
Columbia Acorn Fund		0.12	%		0.43	%		0.07	%		—	%		0.15	%		0.05	%		0.08	%
Columbia Acorn International		0.16	%		0.50	%		0.14	%		0.24	%		0.19	%		0.05	%		0.09	%
Columbia Acorn USA		0.13	%		0.82	%		0.06	%		—	%		0.13	%		0.05	%		0.14	%
Columbia Acorn International Select		0.14	%		0.43	%		0.16	%		—	%		0.12	%		0.05	%		0.09	%
Columbia Acorn Select		0.12	%		0.71	%		0.10	%		—	%		0.14	%		0.05	%		0.10	%
Columbia Thermostat Fund		0.08	%		0.24	%		0.07	%		—	%		0.07	%		0.05	%		0.06	%
Columbia Acorn Emerging Markets Fund		0.12	%		—	%		0.12	%		—	%		0.08	%		0.05	%		0.12	%
Columbia Acorn European Fund		0.11	%		—	%		0.12	%		—	%		0.12	%		0.05	%		0.09	%

Columbia Acorn International and certain other associated investment companies, have severally, but not jointly, guaranteed the performance and observance of all the terms and conditions of a lease entered into by Seligman Data Corp. (SDC), the former transfer agent to certain associated investment companies, including the payment of rent by SDC (the Guaranty). The lease and the Guaranty expire in January 2019. At June 30, 2015, Columbia Acorn International's total potential future obligation over the life of the Guaranty is $73,154. The liability remaining at June 30, 2015 for non-recurring charges associated with the lease amounted to $48,491 and is included within the "Payable for Other liabilities" in the Statements of Assets and Liabilities.

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

The Board has appointed a Chief Compliance Officer of the Trust in accordance with federal securities regulations. The Funds, along with other affiliated funds, are allocated a portion of the expenses associated with the office of the Chief Compliance Officer based on relative net assets of each Fund.

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

An affiliated person of a Fund may include any company in which a Fund owns five percent or more of its outstanding voting shares during the year. On June 30, 2015, Columbia

Acorn Fund, Columbia Acorn International, Columbia Acorn Select and Columbia Thermostat Fund each held five percent or more of the outstanding voting securities of one or more companies or a company which is under common ownership or control with the Funds. Details of investments in those affiliated companies are presented in the Notes to Statement of Investments of each Fund listed above.

For the six months ended June 30, 2015, the Funds engaged in purchase and sales transactions with funds that have a common investment manager (or affiliated investment managers), common directors/trustees, and/or common officers. Those transactions complied with Rule 17a-7 under the 1940 Act and totaled as follows:

	Purchases		Sales
Columbia Acorn Fund	$	2,123,910	$	80,683,340
Columbia Acorn International		5,184,017		4,390,120
Columbia Acorn USA		27,330,576		—
Columbia Acorn International Select		4,390,120		—
Columbia Acorn Select		477,660		1,646,145

5. Borrowing Arrangements

During the period January 1, 2015 through April 29, 2015, the Trust participated in a credit facility with JPMorgan Chase Bank, N.A., along with Wanger Advisors Trust, another trust managed by CWAM, in the amount of $150 million. Effective April 30, 2015, the Trust entered into a revolving credit facility in the amount of $400 million with a syndicate of banks led by JPMorgan Chase Bank, N.A. to facilitate portfolio liquidity. Under each facility, interest is charged to each participating fund based on its borrowings at a rate per annum equal to the Federal Funds Rate plus 1.00%. In addition, a commitment fee of 0.08% per annum of the unutilized line of credit is accrued and apportioned among the participating funds based on their relative net assets. The commitment fee is

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disclosed as a part of "Other expenses" in the Statements of Operations. The Trust expects to renew this line of credit for one year durations each April at then current market rates and terms. No amounts were borrowed for the benefit of a Fund under the line of credit during the six months ended June 30, 2015.

6. Investment Transactions

The aggregate cost of purchases and proceeds from sales, other than short-term obligations, for the six months ended June 30, 2015, were:

	Purchases		Proceeds from Sales
Columbia Acorn Fund	$	1,365,431,754	$	6,751,400,816
Columbia Acorn International		1,770,682,787		1,881,417,841
Columbia Acorn USA		233,724,259		484,621,285
Columbia Acorn International Select		67,375,025		84,896,595
Columbia Acorn Select		200,103,679		309,545,960
Columbia Thermostat Fund		293,214,020		365,608,303
Columbia Acorn Emerging Markets Fund		143,663,333		170,523,998
Columbia Acorn European Fund		22,009,509		6,225,185

The amount of purchase and sales activity impacts the portfolio turnover rate reported in the Financial Highlights.

7. Shareholder Concentration

At June 30, 2015, the table below details the affiliated and significant unaffiliated shareholder account ownership of outstanding shares of each Fund. The Funds have no knowledge about whether any portion of these unaffiliated shares were owned beneficially. Subscription and redemption activity of these accounts may have a significant effect on the operations of the Funds.

Fund	Number of unaffiliated accounts		Percentage of shares outstanding held – unaffiliated			Percentage of shares outstanding held – affiliated
Columbia Acorn Fund		1		13.8	%		—	%
Columbia Acorn International		1		16.9	%		—	%
Columbia Acorn USA		3		56.9	%		—	%
Columbia Acorn International Select		2		38.2	%		11.5	%
Columbia Acorn Select		2		33.4	%		14.1	%
Columbia Thermostat Fund		1		20.0	%		24.5	%
Columbia Acorn Emerging Markets Fund		3		45.0	%		23.5	%
Columbia Acorn European Fund		1		12.2	%		54.8	%

8. Subsequent Events

Management has evaluated the events and transactions that have occurred through the date the financial statements were issued and noted no items requiring adjustment of the financial statements or additional disclosure.

9. Information Regarding Pending and Settled Legal Proceedings

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

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

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BOARD APPROVAL OF THE ADVISORY AGREEMENT

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

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

In connection with their most recent consideration of the Advisory Agreement for each Fund, the Committee and all Trustees received and reviewed a substantial amount of information provided by CWAM, Columbia Management Investment Advisers, LLC ("Columbia Management") and Ameriprise Financial, Inc. ("Ameriprise") in response to written requests from the Independent Trustees and their independent legal counsel. In addition, the Trustees reviewed the Management Fee Evaluation dated June 2015 (the "Fee Evaluation") prepared by the Trust's chief compliance officer, senior vice president and general counsel, at the request of the Board. Throughout the process, the Trustees had numerous opportunities to ask questions of and request additional materials from CWAM, Columbia Management and Ameriprise.

During each meeting at which the Committee or the Independent Trustees considered the Advisory Agreement, they met in executive session with their independent legal counsel. The Committee also met with representatives of

CWAM, Columbia Management and Ameriprise on several occasions. In all, the Committee convened formally on six separate occasions to consider the continuation of the Advisory Agreement. The Board and/or some or all of the Independent Trustees met on other occasions to receive the Committee's status reports, receive presentations from CWAM, Columbia Management and Ameriprise representatives, and to discuss outstanding issues. In addition, the Investment Performance Analysis Committee of the Board, also comprised exclusively of Independent Trustees, reviewed the performance of the Funds, met in two joint meetings with the Contract Committee, and presented its findings to the Board and the Committee throughout the year. The Compliance Committee of the Board also provided information to the Committee with respect to relevant matters.

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

At a meeting held on June 2, 2015 ("Contract Meeting"), the Board considered and unanimously approved

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

Nature, quality and extent of services. The Trustees reviewed the nature, quality and extent of the services provided by CWAM and its affiliates to the Funds under the Advisory Agreement, taking into account the investment objective and strategy of each Fund and knowledge gained from meetings with management, which were held on at least a quarterly basis. In addition, the Trustees reviewed the available resources and key personnel of CWAM and its affiliates, especially those providing investment management services to the Funds. The Trustees also considered other services provided to the Funds by CWAM and its affiliates, including: managing the execution of portfolio transactions and selecting broker-dealers for those transactions; monitoring adherence to the Funds' investment restrictions; producing shareholder reports; providing support services for the Board and committees of the Board; managing the Funds' securities lending program; communicating with shareholders; serving as the Funds' administrator; and overseeing the activities of the Funds' other service providers, including monitoring for compliance with various policies and procedures as well as applicable securities laws and regulations.

The Trustees concluded that the nature, quality and extent of the services provided by CWAM and its affiliates to each Fund under the Advisory Agreement were appropriate for the Funds and that the Funds were likely to benefit from the continued provision of those services by CWAM. They also concluded that CWAM currently had sufficient personnel, with appropriate education and experience, to serve the Funds effectively, and that the firm had demonstrated its continuing ability to attract and retain well-qualified personnel. The Trustees also considered that Ameriprise had committed to the Board that CWAM would have sufficient investment management resources to improve performance, including funds to hire additional analysts and other investment and operational personnel. Based on these

assurances, the Trustees believed that CWAM would have sufficient resources to attract new personnel to improve performance. In addition, they considered the quality of CWAM's compliance record.

Performance of the Funds. The Trustees received and considered detailed performance information at various meetings of the Board, the Committee and the Investment Performance Analysis Committee of the Board throughout the year. They reviewed information comparing each Fund's performance with that of its benchmark(s) and with the performance of comparable funds and peer groups as identified by Lipper Inc. ("Lipper") and Morningstar, Inc. ("Morningstar"). The Trustees evaluated the performance of the Funds over various time periods, including over the one-, three- and five-year periods ending December 31, 2014 as well as longer periods in some cases. The Trustees also considered peer performance rankings for the same time periods. The Trustees generally focus on the three-year period in reaching their assessments. In the case of underperforming Funds, however, the Trustees focused on more recent performance in order to evaluate CWAM's remediation efforts.

The Trustees noted that Columbia Acorn International had outperformed its benchmark over the past three- and five-year periods, and had done so while exposing investors to less risk than competing funds, according to Morningstar, but had underperformed against its peers over the one-, three- and five-year periods. The Trustees noted that the decline in performance was being monitored closely by the Board and the Investment Performance Analysis Committee and that CWAM had discussed with the Performance Committee a number of steps designed to enhance the Funds' performance.

The Trustees considered that Columbia Acorn International Select's performance was well below the median in the Lipper and Morningstar rankings, respectively, for the one-, three- and five-year periods. The Trustees noted that the Fund had outperformed its benchmark during the five-year period, but not in the more recent periods. The Trustees considered CWAM's explanation for the underperformance, which focused on risk aversion. The Trustees had received a plan for the improved performance for the Fund from CWAM, which they continued to monitor.

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The Trustees reviewed the performance for Columbia Acorn Emerging Markets Fund and Columbia Acorn European Fund and noted that both Funds ranked in the top third of Morningstar peers for the three-year period while exposing shareholders to less risk. While Columbia Acorn Emerging Markets Fund had outperformed its benchmark for the three-year period, the Trustees considered that Columbia Acorn European Fund had underperformed its benchmark.

The Trustees considered that the domestic Funds generally had produced unsatisfactory results but that CWAM had put in place a number of intensive remediation plans to improve performance. Columbia Acorn Fund underperformed its peers over the one-, three- and five-year periods, ending December 31, 2014, and the Fund underperformed its benchmark during the same periods. The Trustees also evaluated the Fund's Morningstar risk ratings. They considered CWAM's explanation for the Fund's underperformance, which related to poor security selection and portfolio construction techniques. The Trustees requested and received in 2013 a performance remediation plan from CWAM that included portfolio manager changes, analyst process improvements, incentive compensation changes designed to reward outperformance, and other changes. The Trustees received updated plans in 2014 and early 2015 that emphasized a more disciplined stock selection and portfolio construction process, among other changes. As noted above, the Trustees also sought and received from Ameriprise additional resources for CWAM to enable it to hire additional personnel or other resources for the specific purpose of improving performance. The Trustees understood that the remediation plan may take some time to bear fruit but believed it to be reasonably designed to improve Fund performance.

The Trustees considered that Columbia Acorn Select underperformed its peers and benchmark over the one-, three- and five-year periods ending December 31, 2014 and exposed investors to more risk and volatility versus its peers. The Trustees considered that CWAM had taken steps to reduce risk and volatility in the Fund's portfolio and added additional resources to the management of the Fund in the past year in order to improve performance. The Trustees believed that CWAM was devoting appropriate resources to Columbia Acorn Select's underperformance.

The Trustees considered that Columbia Acorn USA had outperformed its Lipper peer group for the one-year period ending December 31, 2014 but was still lagging in the longer term, although it performed at the median of Morningstar peers for the three-year period while underperforming in other periods. The Trustees noted that the Fund had also underperformed its benchmark in all periods. The Trustees also considered Columbia Acorn USA's risk ratings versus peers. The Trustees considered CWAM's explanation for the Fund's underperformance and concluded that the performance remediation plans implemented by CWAM were reasonably designed to improve the Fund's performance.

The Trustees considered that Columbia Thermostat Fund outperformed its stated benchmark, a 50/50 blend of the Fund's primary equity and debt benchmarks, over the five-year period ending December 31, 2014. It also enjoyed strong rankings from Morningstar versus its peer groups over the five year period, but less so over three years. The Trustees noted that Lipper could not construct an appropriate peer group for the Fund because of its unique strategy and that Morningstar's constantly changing peer group made its ratings somewhat less than reliable. The Trustees noted that more recent performance had declined versus both the benchmark and peers, although the Fund's risk rankings were satisfactory versus peers.

The Trustees concluded that CWAM had taken and continued to take a number of corrective steps to improve performance of the underperforming Funds, that CWAM had reported that these steps were being successfully implemented although still in process; and that the Investment Performance Analysis Committee of the Board was monitoring the underperforming Funds' performance closely. In addition the Trustees considered that the current and former Chief Investment Officer (the "CIO") of CWAM had reported to them at numerous Committee and Board meetings on the corrective steps being taken to improve performance, and Committee representatives met separately with the CIO on multiple occasions to discuss the underperforming Funds.

Costs of Services and Profits Realized by CWAM. At various Committee and Board meetings, the Trustees examined detailed information on the fees and expenses of each Fund in comparison to information for comparable funds provided by Lipper and Morningstar. The Trustees reviewed data from

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Lipper and Morningstar and believed that in general the Funds' total net operating expenses were competitive with peers for Columbia Acorn Fund, Columbia Acorn International, Columbia International Select and Columbia Thermostat Fund and that the Columbia Acorn USA, Columbia Acorn Select and Columbia Emerging Markets Fund had total net operating expenses that were lower than the median in one service but higher than the median in the other service. They considered Columbia Acorn European Fund had total net expenses that were less competitive with its peer groups in both services.

The Trustees also took into account that: the actual advisory fees paid by Columbia Acorn International and Columbia Acorn International Select were lower than both their Morningstar and Lipper peer groups or at the median; the actual advisory fees paid by Columbia Acorn Select, Columbia Acorn USA, Columbia Emerging Markets Fund and Columbia Acorn European Fund were higher than the median advisory fee of the Funds' Lipper and Morningstar peer groups; and the actual advisory fee paid by Columbia Acorn Fund and Columbia Thermostat Fund were below the Funds' Morningstar peer groups, but above the Lipper peer groups. In light of the sustained underperformance of Columbia Acorn Select, the Trustees requested and received at the Contract Meeting a contractual fee waiver from CWAM in the amount of 20 basis points for the advisory fee from CWAM for a one year period ending April 30, 2016.

The Trustees also reviewed the advisory fee rates charged by CWAM for managing other investment companies, sub-advised funds and other institutional separate accounts, as detailed in materials provided to the Committee by CWAM and in the Fee Evaluation. The Trustees noted that the Columbia Acorn Funds' advisory fees were generally comparable to the Columbia Wanger Funds' advisory fees at the same asset levels. The Trustees also examined CWAM's institutional separate account fees for various investment strategies and determined that institutional account advisory fees tended to be lower than the Funds with parallel investment strategies. The Trustees noted that CWAM performs significant additional services for the Funds that it does not provide to sub-advised funds or non-mutual fund clients, including administrative and fund accounting services, oversight of the Funds' other service providers, Trustee support, regulatory compliance and

numerous other services, and that, in servicing the Funds, CWAM assumes many legal and business risks that it does not assume in servicing many of its non-fund clients.

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

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

Other Benefits to CWAM. The Trustees also reviewed benefits that accrue to CWAM and its affiliates from their relationships with the Funds, based upon information provided to them by Ameriprise and as outlined in the Fee Evaluation. They noted that the Funds' transfer agency services are performed by Columbia Management Investment Services Corp., an affiliate of Ameriprise, which receives compensation from the Funds for its services provided. They

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considered that an affiliate of Ameriprise, Columbia Management Investment Distributors, Inc. ("CMID"), serves as the Funds' distributor under a distribution agreement, and that it receives fees under the Columbia Acorn Trust's Rule 12b-1 Plan, most of which CMID pays to broker-dealers, but no fees for its services to the Columbia Wanger Funds. In addition, Columbia Management provides sub-administration services to the Funds. The Committee received information regarding the profitability of each Fund agreement with CWAM affiliates. The Committee and the Board also reviewed information about and discussed the capabilities of each affiliated entity in performing its duties.

The Trustees considered other ways that the Funds and CWAM may potentially benefit from their relationship with each other. For example, the Trustees considered CWAM's use of commissions paid by each Fund on its portfolio brokerage transactions to obtain research products and services benefiting the Funds and/or other clients of CWAM. The Compliance Committee of the Board reviewed CWAM's annual "soft dollar" report during the year and met with representatives from CWAM to review CWAM's soft dollar spending. The Trustees also considered that the Compliance Committee regularly reviewed third-party prepared reports that evaluated the quality of CWAM's execution of the Funds' portfolio transactions. The Trustees noted that these reports showed that CWAM's execution capabilities were generally better than industry peers. The Trustees determined that CWAM's use of the Funds' "soft" commission dollars to obtain research products and services was consistent with current regulatory requirements and guidance. They also concluded that CWAM benefits from the receipt of proprietary research products and services acquired through commissions paid on portfolio transactions of the Funds, and that the Funds benefitted from CWAM's receipt of those products and services as well as research products and services acquired through commissions paid by other clients of CWAM. Finally, the Trustees considered that CWAM's affiliates benefit from management fees received from Columbia Thermostat's investment in other Columbia mutual funds.

After full consideration of the above factors, as well as other factors that were instructive in evaluating the Advisory Agreement, the Trustees, including the Independent Trustees by separate vote, concluded that the advisory fees

were reasonable and that the continuation of the Advisory Agreement was in the best interest of each Fund. At the Contract Meeting, the Trustees approved continuation of the Advisory Agreement through July 31, 2016.

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PROXY VOTING RESULTS

RESULTS OF SPECIAL MEETING OF SHAREHOLDERS (UNAUDITED)

A Special Meeting of Shareholders of Columbia Acorn Trust (the Trust), was held on February 27, 2015 to ask shareholders to vote in favor of the election of nine nominated trustees to the Board. A proxy statement that described the proposals was mailed to shareholders of record as of December 31, 2014.

Proposal: Each of the trustee nominees was elected to the Board as follows:

Trustee	For		Against/Withhold		Abstain/Broker Non-Votes
Laura M. Born		639,164,070.883		10,694,881.943		0
Maureen M. Culhane		638,800,970.381		11,057,982.445		0
Margaret M. Eisen		638,866,948.678		10,992,004.148		0
Thomas M. Goldstein		639,138,773.640		10,720,179.186		0
John C. Heaton		553,323,641.483		96,535,311.343		0
Steven N. Kaplan		638,876,388.150		10,982,564.676		0
Charles R. Phillips		639,256,774.865		10,602,177.961		0
David J. Rudis		553,224,405.014		96,634,547.812		0
P. Zachary Egan		639,498,208.627		10,360,744.199		0

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COLUMBIA ACORN FAMILY OF FUNDS

DESCRIPTIONS OF INDEXES INCLUDED IN THIS REPORT

• 50/50 Blended Benchmark, established by the Fund's investment manager, is an equally weighted custom composite of Columbia Thermostat Fund's primary equity and primary debt benchmarks, the S&P 500® Index and the Barclays U.S. Aggregate Bond Index, respectively. The percentage of the Fund's assets allocated to underlying stock and bond portfolio funds will vary, and accordingly the composition of the Fund's portfolio will not always reflect the composition of the 50/50 Blended Benchmark.

• Barclays U.S. Aggregate Bond Index is a market value-weighted index that tracks the daily price, coupon, pay-downs and total return performance of fixed-rate, publicly placed, dollar-denominated and non-convertible investment grade debt issues with at least $250 million par amount outstanding and with at least one year to final maturity.

• Euromoney Smaller European Companies (inc. UK) Index is an index of smaller companies in Europe including the UK market. The Euromoney Smaller European Companies Index covers companies of small- and mid-cap market capitalization in Europe's developed markets. The index is rebalanced on a quarterly basis.

• Lipper Indexes are composed of the 10 or 30 largest funds in the Lipper investment objective grouping. Lipper Mid-Cap Growth Funds Index, 30 largest mid-cap growth funds, including Columbia Acorn Fund; Lipper International Small/Mid Growth Funds Index, 10 largest non-U.S. small/mid growth funds, including Columbia Acorn International and Columbia Acorn International Select; Lipper Small-Cap Growth Funds Index, 30 largest small-cap growth funds, including Columbia Acorn USA; Lipper Mid-Cap Core Funds Index, 30 largest mid-cap core funds; Lipper Flexible Portfolio Funds Index, an equal-weighted index of the 30 largest mutual funds within the Flexible Portfolio fund classification, as defined by Lipper; Lipper Emerging Markets Index, 30 largest emerging markets funds; Lipper European Region Index, 10 largest European funds.

• MSCI Europe, Australasia and Far East (EAFE) Index (Net) is a capitalization-weighted index that tracks the total return of common stocks in 21 developed-market countries within Europe, Australasia and the Far East. The returns of the MSCI EAFE Index (Net) are presented net of the withholding tax rate applicable to foreign non-resident institutional investors in the foreign companies included in the index who do not benefit from double taxation treaties.

• MSCI Emerging Markets Small Cap Index (Net), a widely recognized international benchmark, is a free float-adjusted market capitalization index that is designed to measure small-cap emerging market equity performance in 23 emerging market countries, as determined by MSCI. The MSCI Emerging Markets Small Cap Index (Net) currently consists of the following emerging market country indexes: Brazil, Chile, China, Colombia, Czech Republic, Egypt, Greece, Hungary, India, Indonesia, Korea, Malaysia, Mexico, Peru, Philippines, Poland, Qatar, Russia, South Africa, Taiwan, Thailand, Turkey and United Arab Emirates.

• Russell 2000 Index measures the performance of the 2,000 smallest companies in the Russell 3000 Index, which represents approximately 10% of the total market capitalization of the Russell 3000 Index.

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

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

• S&P MidCap 400® Index is a market value-weighted index that tracks the performance of 400 mid-cap U.S. companies.

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

• S&P Emerging Markets Between $500M and $5B® Index represents the institutionally investable capital of 23 emerging market countries, as determined by S&P, with market caps ranging between $500 million to $5 billion. The index currently consists of the following emerging market country indexes: Brazil, Chile, China, Colombia, Czech Republic, Egypt, Greece, Hungary, India, Indonesia, Malaysia, Mexico, Morocco, Peru, Philippines, Poland, Qatar, Russia, South Africa, Taiwan, Thailand, Turkey and United Arab Emirates.

• S&P Europe Between $500M and $5B® Index represents the institutionally investable capital of 16 European countries, as determined by S&P, with market caps ranging between $500 million to $5 billion. The index consists of the following European countries: Austria, Belgium, Denmark, Finland, France, Germany, Ireland, Italy, Luxembourg, the Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom.

• S&P Global Ex-U.S. SmallCap® Index consists of the bottom 20% of institutionally investable capital of developed and emerging countries, excluding the United States.

• S&P Global Ex-U.S. Between $500M and $5B® Index is a subset of the broad market selected by the index sponsor that represents the mid- and small-cap developed and emerging markets, excluding the United States.

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

126

COLUMBIA ACORN FAMILY OF FUNDS EXPENSE INFORMATION

as of 6/30/15

Columbia Acorn® Fund	Class A			Class B^(a)			Class C			Class I			Class R			Class R4			Class R5			Class Y			Class Z
Management Fees		0.64	%		0.64	%		0.64	%		0.64	%					0.64	%		0.64	%		0.64	%		0.64	%
Distribution and Service (12b-1) Fees		0.25	%		0.75	%		1.00	%		0.00	%					0.00	%		0.00	%		0.00	%		0.00	%
Other Expenses		0.20	%		0.50	%		0.15	%		0.08	%					0.23	%		0.13	%		0.08	%		0.16	%
Net Expense Ratio		1.09	%		1.89	%		1.79	%		0.72	%					0.87	%		0.77	%		0.72	%		0.80	%
Columbia Acorn International®
Management Fees		0.76	%		0.76	%		0.76	%		0.76	%		0.76	%		0.76	%		0.76	%		0.76	%		0.76	%
Distribution and Service (12b-1) Fees		0.25	%		0.75	%		1.00	%		0.00	%		0.50	%		0.00	%		0.00	%		0.00	%		0.00	%
Other Expenses		0.23	%		0.57	%		0.22	%		0.11	%		0.34	%		0.29	%		0.15	%		0.11	%		0.19	%
Net Expense Ratio		1.24	%		2.08	%		1.98	%		0.87	%		1.60	%		1.05	%		0.91	%		0.87	%		0.95	%
Columbia Acorn USA®
Management Fees		0.87	%		0.87	%		0.87	%		0.87	%					0.87	%		0.87	%		0.87	%		0.87	%
Distribution and Service (12b-1) Fees		0.25	%		0.75	%		1.00	%		0.00	%					0.00	%		0.00	%		0.00	%		0.00	%
Other Expenses		0.22	%		0.90	%		0.14	%		0.06	%					0.22	%		0.13	%		0.08	%		0.22	%
Net Expense Ratio		1.34	%		2.52	%		2.01	%		0.93	%					1.09	%		1.00	%		0.95	%		1.09	%
Columbia Acorn International Select^SM
Management Fees		0.94	%		0.94	%		0.94	%		0.94	%					0.94	%		0.94	%		0.94	%		0.94	%
Distribution and Service (12b-1) Fees		0.25	%		0.75	%		1.00	%		0.00	%					0.00	%		0.00	%		0.00	%		0.00	%
Other Expenses		0.33	%		0.51	%		0.35	%		0.25	%					0.31	%		0.24	%		0.18	%		0.28	%
Net Expense Ratio		1.52	%		2.20	%		2.29	%		1.19	%					1.25	%		1.18	%		1.12	%		1.22	%
Columbia Acorn Select^SM
Management Fees		0.78	%		0.78	%		0.78	%		0.78	%					0.78	%		0.78	%		0.78	%		0.78	%
Distribution and Service (12b-1) Fees		0.25	%		0.75	%		1.00	%		0.00	%					0.00	%		0.00	%		0.00	%		0.00	%
Other Expenses		0.24	%		0.57	%		0.22	%		0.10	%					0.26	%		0.19	%		0.12	%		0.22	%
Net Expense Ratio		1.27	%		2.10	%		2.00	%		0.88	%					1.04	%		0.97	%		0.90	%		1.00	%
Columbia Thermostat Fund^SM
Management Fees		0.10	%		0.10	%		0.10	%								0.10	%		0.10	%		0.10	%		0.10	%
Distribution and Service (12b-1) Fees		0.25	%		0.75	%		1.00	%								0.00	%		0.00	%		0.00	%		0.00	%
Other Expenses		0.15	%		0.15	%		0.15	%								0.15	%		0.13	%		0.08	%		0.14	%
Net Expense Ratio^(b)		0.50	%		1.00	%		1.25	%								0.25	%		0.23	%		0.18	%		0.24	%
Columbia Acorn Emerging Markets Fund^SM(c)
Management Fees		1.05	%					1.05	%		1.05	%					1.05	%		1.05	%		1.05	%		1.05	%
Distribution and Service (12b-1) Fees		0.25	%					1.00	%		0.00	%					0.00	%		0.00	%		0.00	%		0.00	%
Other Expenses		0.32	%					0.33	%		0.24	%					0.28	%		0.26	%		0.18	%		0.32	%
Net Expense Ratio		1.62	%					2.38	%		1.29	%					1.33	%		1.31	%		1.23	%		1.37	%
Columbia Acorn European Fund^SM
Management Fees		1.19	%					1.19	%		1.19	%					1.19	%		1.19	%					1.19	%
Distribution and Service (12b-1) Fees		0.25	%					1.00	%		0.00	%					0.00	%		0.00	%					0.00	%
Other Expenses		0.31	%					0.31	%		0.26	%					0.31	%		0.31	%					0.31	%
Net Expense Ratio		1.75	%					2.50	%		1.45	%					1.50	%		1.50	%					1.50	%

See the Funds' prospectuses for information on minimum initial investment amounts and other details of buying, selling and exchanging shares of the Funds.

Fees and expenses are for the six months ended June 30, 2015. The fees and expenses of Columbia Acorn International Select and Columbia Acorn Select include the effect of the voluntary undertaking by Columbia Wanger Asset Management, LLC (CWAM) to reimburse each Fund so that the ordinary operating expenses (excluding transaction costs and certain other investment-related expenses, interest and fees on borrowings and expenses associated with the Fund's investment in other investment companies, if any), after giving effect to any balance credits or overdraft charges from the Fund's custodian, do not exceed the following annual rates as a percentage of each class' average daily net assets:

Fund	Class A			Class B			Class C			Class I			Class R4			Class R5			Class Y			Class Z
Columbia Acorn International Select		1.70	%		2.20	%		2.45	%		1.37	%		1.45	%		1.42	%		1.37	%		1.45	%
Columbia Acorn Select		1.60	%		2.10	%		2.35	%		1.25	%		1.35	%		1.30	%		1.25	%		1.35	%

These arrangements may be modified or terminated by either the Funds or CWAM on 30 days' notice.

Effective May 1, 2015, CWAM has contractually agreed to waive 0.20% of the advisory fee otherwise payable to it by Columbia Acorn Select through April 30, 2016. When determining whether the Fund's total expenses exceed the voluntary expense cap described above, the Fund's net advisory fee, reflecting application of the 0.20% waiver, will be used to calculate the Fund's total expenses. This arrangement may only be modified or amended with approval from all parties to the arrangement, including the Fund and CWAM.

The fees and expenses of Columbia Thermostat Fund include the effect of CWAM's contractual undertaking to waive fees and/or reimburse expenses of the Fund so that the ordinary operating expenses (excluding transaction costs and certain other investment-related expenses, interest and fees on borrowings and expenses associated with the Fund's investment in underlying portfolio funds), do not exceed annually the rates of 0.50%, 1.00%, 1.25%, 0.25%, 0.24%, 0.19% and 0.25% of the Fund's average daily net assets attributable to Class A, Class B, Class C, Class R4, Class R5, Class Y and Class Z shares, respectively, through April 30, 2016. There is no guarantee that this agreement will continue thereafter.

The fees and expenses of Columbia Acorn Emerging Markets Fund and Columbia Acorn European Fund include the effect of CWAM's contractual undertaking to waive fees and/or reimburse expenses of each Fund so that the ordinary operating expenses (excluding transaction costs and certain other investment-related expenses, interest and fees on borrowings and expenses associated with the Fund's investment in other investment companies, if any), of each Fund's Class A, Class C, Class I, Class R4, Class R5, Class Y (if offered) and Class Z shares through April 30, 2016, do not exceed the following annual rates as a percentage of each class' average daily net assets:

Fund	Class A			Class C			Class I			Class R4			Class R5			Class Y			Class Z
Columbia Acorn Emerging Markets Fund		1.85	%		2.60	%		1.48	%		1.60	%		1.53	%		1.48	%		1.60	%
Columbia Acorn European Fund		1.75	%		2.50	%		1.41	%		1.50	%		1.46	%		—			1.50	%

There is no guarantee that these arrangements will continue thereafter.

The fees and expenses of Columbia Acorn International include the effect of the voluntary undertaking by CMIS to waive a portion of total annual Fund operating expenses attributable to transfer agency expenses incurred by Class A, Class B and Class C shares of Columbia Acorn International such that the Fund's total annual Fund operating expenses will be reduced by 0.04%, 0.03% and 0.02% for Class A, Class B and Class C shares of the Fund, respectively.

(a) The Funds generally no longer accept investments by new or existing investors in Class B shares, except in connection with the reinvestment of any dividend and/or capital gain distributions in Class B shares of the Funds and exchanges by existing Class B shareholders of certain other funds within the Columbia Acorn Family of Funds.

(b) Does not include estimated fees and expenses of 0.51% incurred by the Fund from the underlying portfolio funds in which it invests.

(c) Effective July 11, 2014, Columbia Acorn Emerging Markets Fund is closed to most new investors and new accounts, except as described in the Fund's prospectus, dated May 1, 2015.

127

COLUMBIA ACORN FAMILY OF FUNDS

Trustees

Laura M. Born

Chair of the Board

Steven N. Kaplan

Vice Chair of the Board

Maureen M. Culhane

P. Zachary Egan

Margaret M. Eisen

Thomas M. Goldstein

John C. Heaton

Charles R. Phillips

David J. Rudis

Ralph Wanger (Trustee Emeritus)

Officers

P. Zachary Egan

President

Alan G. Berkshire

Vice President

Robert A. Chalupnik

Vice President

Michael G. Clarke

Assistant Treasurer

Joseph F. DiMaria

Assistant Treasurer

William J. Doyle

Vice President

David L. Frank

Vice President

Paul B. Goucher

Assistant Secretary

Fritz Kaegi

Vice President

John M. Kunka

Treasurer and Principal Accounting and Financial Officer

Stephen Kusmierczak

Vice President

Joseph C. LaPalm

Vice President

Ryan C. Larrenaga

Assistant Secretary

Satoshi Matsunaga

Vice President

Charles P. McQuaid

Vice President

Louis J. Mendes

Vice President

Robert A. Mohn

Vice President

Christopher J. Olson

Vice President

Robert P. Scales

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

Matthew S. Szafranski

Vice President

Andreas Waldburg-Wolfegg

Vice President

Linda K. Roth-Wiszowaty

Secretary

Investment Manager

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

1-800-922-6769

Distributor

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

Transfer Agent, Dividend Disbursing Agent

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

1-800-345-6611

Legal Counsel to the Funds

Perkins Coie LLP
Washington, DC

Legal Counsel to the Independent Trustees

Drinker Biddle & Reath LLP
Philadelphia, Pennsylvania

Independent Registered Public Accounting Firm

PricewaterhouseCoopers LLP
Chicago, Illinois

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

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

The Funds file a complete schedule of portfolio holdings with the SEC for the first and third quarters of each fiscal year on Form N-Q. The Funds' Form N-Q is available on the SEC's website at www.sec.gov and may be reviewed and copied at the SEC's Public Reference Room in Washington, D.C. Information on the operation of the Public Reference Room may be obtained by calling 1-800-SEC-0330. The Funds' complete portfolio holdings are disclosed at columbiathreadneedle.com/us approximately 30 to 40 days after each month-end.

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

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

Find out what's new – visit our website at:

columbiathreadneedle.com/us

Our e-mail address is:

serviceinquiries@columbiathreadneedle.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.

128

This document contains Global Industry Classification Standard data. The Global Industry Classification Standard ("GICS") was developed by and is the exclusive property and a service mark of MSCI Inc. ("MSCI") and Standard & Poor's Financial Services LLC ("S&P") and is licensed for use by Columbia Wanger Asset Management, LLC. Neither MSCI, S&P, nor any other party involved in making or compiling the GICS or any GICS classifications makes any express or implied warranties or representations with respect to such standard or classification (or the results to be obtained by the use thereof), and all such parties hereby expressly disclaim all warranties of originality, accuracy, completeness, merchantability and fitness for a particular purpose with respect to any of such standard or classification. Without limiting any of the foregoing, in no event shall MSCI, S&P, any of their affiliates or any third party involved in making or compiling the GICS or any GICS classifications have any liability for any direct, indirect, special, punitive, consequential or any other damages (including lost profits) even if notified of the possibility of such damages.

Columbia Acorn Family of Funds
Class A, B, C, I, R, R4, R5, Y and Z Shares

Semiannual Report, June 30, 2015
225 Franklin Street, Boston, MA 02110

For More Information

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

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

By Telephone: 800.345.6611

Online: columbiathreadneedle.com/us

Shareholder Communications with the Board

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

Prospectuses and the Statement of Additional Information (SAI)

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

Information Provided by the SEC

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

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

800.345.6611 columbiathreadneedle.com/us

SAR110_12_E01_(08/15) 1275823

Item 2. Code of Ethics.

Not applicable for semiannual reports.

Item 3. Audit Committee Financial Expert.

Not applicable for semiannual reports.

Item 4. Principal Accountant Fees and Services.

Not applicable for semiannual reports.

Item 5. Audit Committee of Listed Registrants.

Not applicable.

Item 6. Investments

(a) The registrant’s “Schedule I — Investments in securities of unaffiliated issuers” (as set forth in 17 CFR 210.12-12) is included in Item 1 of this Form N-CSR.

(b) Not applicable.

Item 7. Disclosure of Proxy Voting Policies and Procedures for Closed-End Management Investment Companies.

Not applicable.

Item 8. Portfolio Managers of Closed-End Management Investment Companies.

Not applicable.

Item 9. Purchases of Equity Securities by Closed-End Management Investment Company and Affiliated Purchasers.

Not applicable.

Item 10. Submission of Matters to a Vote of Security Holders.

There were no material changes to the procedures by which shareholders may recommend nominees to the registrant’s board of directors.

Item 11. Controls and Procedures.

(a) The registrant’s principal executive officer and principal financial officers, based on their evaluation of the registrant’s disclosure controls and procedures as of a date within 90 days of the filing of this report, have concluded that such controls and procedures are adequately designed to ensure that material information required to be disclosed by the registrant in Form N-CSR is accumulated and communicated to the registrant’s management, including the principal executive officer and principal financial officer, or persons performing similar functions, as appropriate to allow timely decisions regarding required disclosure.

(b) There was no change in the registrant’s internal control over financial reporting that occurred during the registrant’s second fiscal quarter of the period covered by this report that has materially affected, or is reasonably likely to materially affect, the registrant’s internal control over financial reporting.

Item 12. Exhibits.

(a)(1) Code of ethics required to be disclosed under Item 2 of Form N-CSR: Not applicable for semiannual reports.

(a)(2) Certifications pursuant to Rule 30a-2(a) under the Investment Company Act of 1940 (17 CFR 270.30a-2(a)) attached hereto as Exhibit 99.CERT.

(a)(3) Not applicable.

(b) Certification pursuant to Rule 30a-2(b) under the Investment Company Act of 1940 (17 CFR 270.30a-2(b)) attached hereto as Exhibit 99.906CERT.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934 and the Investment Company Act of 1940, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

(registrant)				Columbia Acorn Trust


By (Signature and Title)				/s/ P. Zachary Egan
				P. Zachary Egan, President


Date				August 19, 2015

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/ P. Zachary Egan
				P. Zachary Egan, President


Date				August 19, 2015


By (Signature and Title)				/s/ John M. Kunka
				John M. Kunka, Treasurer


Date				August 19, 2015

Columbia Thermostat Fund (CTFAX) N-CSRSCertified semi-annual shareholder report (management investment company)