FIRST QUARTER REPORT

March 31, 2016

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 3/31/16

	Columbia Acorn® Fund		Columbia Acorn International®		Columbia Acorn USA®		Columbia Acorn International SelectSM		Columbia Acorn SelectSM		Columbia Thermostat FundSM		Columbia Acorn Emerging Markets FundSM		Columbia Acorn European FundSM
Class A	$	17.14	$	39.10	$	19.01	$	20.90	$	13.89	$	14.56	$	10.18	$	14.91
Class B	$	13.28	$	37.71	$	14.57	$	19.65	$	10.76	$	14.65		N/A		N/A
Class C	$	12.77	$	37.60	$	15.00	$	19.53	$	10.45	$	14.64	$	10.12	$	14.77
Class I	$	18.91	$	39.22	$	21.05	$	21.17	$	15.31		N/A	$	10.21	$	14.91
Class R		N/A	$	39.06		N/A		N/A		N/A		N/A		N/A		N/A
Class R4	$	19.30	$	39.45	$	21.46	$	21.32	$	15.64	$	14.45	$	10.27	$	14.99
Class R5	$	19.38	$	39.16	$	21.51	$	21.31	$	15.69	$	14.47	$	10.27	$	15.06
Class Y	$	19.46	$	39.47	$	21.61	$	21.30	$	15.79	$	14.45	$	10.17		N/A
Class Z	$	18.82	$	39.17	$	20.85	$	21.17	$	15.19	$	14.38	$	10.20	$	14.92

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.

2016 MID-YEAR CAPITAL GAIN DISTRIBUTION ESTIMATES¹

Fund Name	Record Date	Ex-dividend/ Payable Date	Range of Estimated Total Capital Gain Distribution2	Class A 4/29 NAV		Range of Total Capital Gain Distribution as % of Class A NAV
Columbia Acorn Fund	June 6, 2016	June 7, 2016	$1.85 to $2.10	$	17.33	10.68% to 12.12%
Columbia Acorn International	June 6, 2016	June 7, 2016	$0.25 to $0.30	$	39.29	0.64% to 0.76%
Columbia Acorn USA	June 6, 2016	June 7, 2016	$2.50 to $3.00	$	19.56	12.78% to 15.34%
Columbia Acorn International Select	June 6, 2016	June 7, 2016	None	$	21.00	—
Columbia Acorn Select	June 6, 2016	June 7, 2016	$1.15 to $1.30	$	13.69	8.40% to 9.50%
Columbia Thermostat Fund	June 6, 2016	June 7, 2016	$0.27 to $0.32	$	14.69	1.84% to 2.18%
Columbia Acorn Emerging Markets Fund	June 6, 2016	June 7, 2016	None	$	10.40	—
Columbia Acorn European Fund	June 6, 2016	June 7, 2016	None	$	14.92	—

¹  Columbia Wanger Asset Management, LLC and Columbia Threadneedle Investments do not 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 Funds.

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	25
Statement of Investments	27
Columbia Acorn International®
In a Nutshell	6
At a Glance	7
Major Portfolio Changes	34
Statement of Investments	37
Portfolio Diversification	43
Columbia Acorn USA®
In a Nutshell	8
At a Glance	9
Major Portfolio Changes	44
Statement of Investments	46
Columbia Acorn International SelectSM
In a Nutshell	10
At a Glance	11
Major Portfolio Changes	51
Statement of Investments	52
Portfolio Diversification	56
Columbia Acorn SelectSM
In a Nutshell	12
At a Glance	13
Major Portfolio Changes	57
Statement of Investments	58

Columbia Thermostat FundSM
In a Nutshell	14
At a Glance	15
Statement of Investments	62
Columbia Acorn Emerging Markets FundSM
In a Nutshell	16
At a Glance	17
Major Portfolio Changes	64
Statement of Investments	66
Portfolio Diversification	70
Columbia Acorn European FundSM
In a Nutshell	18
At a Glance	19
Major Portfolio Changes	71
Statement of Investments	73
Portfolio Diversification	77
Squirrel Chatter: Peak Everything	20
Descriptions of Indexes	24
Columbia Acorn Family of Funds
Expense Information	79

1

COLUMBIA ACORN FAMILY OF FUNDS

SHARE CLASS PERFORMANCE Average Annual Total Returns through 3/31/16

	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*		-2.78	%		-8.39	%		-3.07	%		-7.91	%		-2.96	%		-3.93	%		-2.68	%		N/A			-2.72	%		-2.71	%		-2.70	%		-2.69	%
1 year		-8.18	%		-13.45	%		-9.15	%		-11.56	%		-8.83	%		-9.31	%		-7.85	%		N/A			-8.07	%		-7.92	%		-7.87	%		-7.88	%
5 years		5.81	%		4.57	%		5.08	%		4.93	%		5.05	%		5.05	%		6.19	%		N/A			6.06	%		6.13	%		6.17	%		6.12	%
10 years		5.29	%		4.67	%		4.60	%		4.60	%		4.50	%		4.50	%		5.64	%		N/A			5.57	%		5.61	%		5.63	%		5.60	%
Columbia Acorn International®
Year to date*		0.05	%		-5.69	%		-0.24	%		-5.23	%		-0.13	%		-1.13	%		0.18	%		-0.03	%		0.10	%		0.15	%		0.15	%		0.13	%
1 year		-5.58	%		-11.00	%		-6.56	%		-11.05	%		-6.28	%		-7.18	%		-5.21	%		-5.93	%		-5.41	%		-5.25	%		-5.23	%		-5.31	%
5 years		3.28	%		2.07	%		2.46	%		2.12	%		2.51	%		2.51	%		3.68	%		2.92	%		3.55	%		3.63	%		3.66	%		3.60	%
10 years		4.82	%		4.20	%		4.08	%		4.08	%		4.02	%		4.02	%		5.21	%		4.49	%		5.14	%		5.17	%		5.19	%		5.16	%
Columbia Acorn USA®
Year to date*		-6.12	%		-11.54	%		-9.22	%		-13.76	%		-6.25	%		-7.19	%		-6.03	%		N/A			-6.08	%		-6.07	%		-6.00	%		-6.04	%
1 year		-12.09	%		-17.15	%		-16.19	%		-18.94	%		-12.66	%		-13.23	%		-11.70	%		N/A			-11.89	%		-11.79	%		-11.71	%		-11.83	%
5 years		5.76	%		4.51	%		4.12	%		3.93	%		5.03	%		5.03	%		6.18	%		N/A			6.03	%		6.08	%		6.13	%		6.03	%
10 years		4.53	%		3.91	%		3.37	%		3.37	%		3.76	%		3.76	%		4.89	%		N/A			4.81	%		4.84	%		4.86	%		4.81	%
Columbia Acorn International SelectSM
Year to date*		-2.02	%		-7.64	%		-2.19	%		-7.08	%		-2.15	%		-3.13	%		-1.85	%		N/A			-1.93	%		-1.89	%		-1.89	%		-1.90	%
1 year		-4.63	%		-10.10	%		-5.28	%		-9.97	%		-5.35	%		-6.29	%		-4.22	%		N/A			-4.37	%		-4.27	%		-4.21	%		-4.32	%
5 years		1.94	%		0.74	%		1.27	%		1.00	%		1.16	%		1.16	%		2.33	%		N/A			2.23	%		2.28	%		2.32	%		2.26	%
10 years		4.30	%		3.69	%		3.62	%		3.62	%		3.49	%		3.49	%		4.68	%		N/A			4.63	%		4.66	%		4.67	%		4.64	%
Columbia Acorn SelectSM
Year to date*		-0.36	%		-6.09	%		-0.55	%		-5.53	%		-0.57	%		-1.57	%		-0.33	%		N/A			-0.32	%		-0.32	%		-0.25	%		-0.33	%
1 year		-3.74	%		-9.28	%		-4.56	%		-7.47	%		-4.46	%		-5.03	%		-3.47	%		N/A			-3.56	%		-3.50	%		-3.43	%		-3.49	%
5 years		5.47	%		4.23	%		4.71	%		4.57	%		4.70	%		4.70	%		5.87	%		N/A			5.73	%		5.78	%		5.83	%		5.77	%
10 years		5.03	%		4.41	%		4.32	%		4.32	%		4.22	%		4.22	%		5.39	%		N/A			5.31	%		5.34	%		5.36	%		5.33	%
Columbia Thermostat FundSM
Year to date*		1.75	%		-4.08	%		1.60	%		-3.40	%		1.60	%		0.60	%		N/A			N/A			1.83	%		1.90	%		1.90	%		1.84	%
1 year		0.40	%		-5.38	%		-0.11	%		-4.94	%		-0.36	%		-1.33	%		N/A			N/A			0.66	%		0.74	%		0.73	%		0.67	%
5 years		6.12	%		4.88	%		5.60	%		5.28	%		5.35	%		5.35	%		N/A			N/A			6.38	%		6.41	%		6.44	%		6.39	%
10 years		5.62	%		4.99	%		5.09	%		5.09	%		4.83	%		4.83	%		N/A			N/A			5.88	%		5.90	%		5.91	%		5.88	%
Columbia Acorn Emerging Markets FundSM
Year to date*		-0.59	%		-6.26	%		N/A			N/A			-0.78	%		-1.78	%		-0.49	%		N/A			-0.48	%		-0.48	%		-0.59	%		-0.58	%
1 year		-18.02	%		-22.74	%		N/A			N/A			-18.63	%		-19.44	%		-17.70	%		N/A			-17.73	%		-17.65	%		-17.67	%		-17.81	%
Life of Fund		1.13	%		-0.16	%		N/A			N/A			0.40	%		0.40	%		1.52	%		N/A			1.47	%		1.50	%		1.50	%		1.41	%
Columbia Acorn European FundSM
Year to date*		1.08	%		-4.73	%		N/A			N/A			0.96	%		-0.04	%		1.15	%		N/A			1.15	%		1.14	%		N/A			1.15	%
1 year		0.93	%		-4.86	%		N/A			N/A			0.22	%		-0.78	%		1.26	%		N/A			1.25	%		1.19	%		N/A			1.18	%
Life of Fund		9.91	%		8.51	%		N/A			N/A			9.12	%		9.12	%		10.24	%		N/A			10.22	%		10.20	%		N/A			10.20	%

*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 79 of this report for information on contractual fee waiver and expense reimbursement agreements in place on March 31, 2016, 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.

2

FUND PERFORMANCE VS. BENCHMARKS Class Z Average Annual Total Returns through 3/31/16

Class Z Shares	1st* quarter			1 year			5 years			10 years			Life of Fund
Columbia Acorn® Fund (ACRNX) (6/10/70)		-2.69	%		-7.88	%		6.12	%		5.60	%		14.06	%
Russell 2500 Index		0.39	%		-7.31	%		8.58	%		6.47	%		N/A
S&P 500 Index**		1.35	%		1.78	%		11.58	%		7.01	%		10.80	%
Columbia Acorn International® (ACINX) (9/23/92)		0.13	%		-5.31	%		3.60	%		5.16	%		10.22	%
MSCI ACWI Ex USA SMID Cap Index (Net)		1.03	%		-2.46	%		2.05	%		3.37	%		N/A
S&P Global Ex-U.S. Between $500M and $5B Index		1.73	%		-2.83	%		2.58	%		4.49	%		7.94	%
Columbia Acorn USA® (AUSAX) (9/4/96)		-6.04	%		-11.83	%		6.03	%		4.81	%		9.66	%
Russell 2000 Index		-1.52	%		-9.76	%		7.20	%		5.26	%		7.78	%
Columbia Acorn Int'l SelectSM (ACFFX) (11/23/98)		-1.90	%		-4.32	%		2.26	%		4.64	%		7.95	%
MSCI ACWI Ex USA Index (Net)		-0.38	%		-9.19	%		0.31	%		1.94	%		N/A
S&P Developed Ex-U.S. Between $2B and $10B Index		0.84	%		-0.74	%		4.00	%		3.71	%		7.15	%
Columbia Acorn SelectSM (ACTWX) (11/23/98)		-0.33	%		-3.49	%		5.77	%		5.33	%		9.46	%
S&P MidCap 400 Index		3.78	%		-3.60	%		9.52	%		7.78	%		9.91	%
Columbia Thermostat FundSM (COTZX) (9/25/02)		1.84	%		0.67	%		6.39	%		5.88	%		7.40	%
S&P 500 Index		1.35	%		1.78	%		11.58	%		7.01	%		9.27	%
Barclays U.S. Aggregate Bond Index		3.03	%		1.96	%		3.78	%		4.90	%		4.51	%
50/50 Blended Benchmark		2.28	%		2.12	%		7.83	%		6.27	%		7.15	%
Columbia Acorn Emerging Markets FundSM (CEFZX) (8/19/11)		-0.58	%		-17.81	%		—			—			1.41	%
MSCI Emerging Markets SMID Cap Index (Net)		3.06	%		-10.23	%		—			—			-1.46	%
S&P Emerging Markets Between $500M and $5B Index		4.73	%		-10.71	%		—			—			0.32	%
Columbia Acorn European FundSM (CAEZX) (8/19/11)		1.15	%		1.18	%		—			—			10.20	%
MSCI AC Europe Small Cap Index (Net)		-0.87	%		4.60	%		—			—			11.88	%
S&P Europe Between $500M and $5B Index		-1.22	%		3.02	%		—			—			11.85	%

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 24 for a description of the indexes listed above.

3

COLUMBIA ACORN® FUND

IN A NUTSHELL

P. Zachary Egan Co-Portfolio Manager	Fritz Kaegi Co-Portfolio Manager

Matthew A. Litfin
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 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 fell 2.69% in the first quarter of 2016, underperforming the 0.39% gain of the Fund's primary benchmark, the Russell 2500 Index. Value names within the benchmark outperformed growth in the quarter, which hurt performance of the Fund's more growth-oriented portfolio.

The uptick in value stocks negatively impacted sectors that are more sensitive to growth expectations. These include the information technology (IT) and health care sectors, two areas that were weak for the Fund in the quarter. Within the IT sector, the Fund's overweight in the software and services industry was a significant relative detractor. Bankrate, a provider of internet advertising for the insurance, credit card and banking markets, fell 32% in the quarter on concerns around increased competition from Google. Given the increasingly uncertain competitive landscape for Bankrate, we opted to reduce the Fund's exposure to the stock during the quarter.

The health care sector in general suffered from concerns about the potential impact of the upcoming presidential election, and general fears that prices for drugs and other medical treatments will come under increased pressure going forward. While Fund holdings in the health care equipment and services industries performed in line with the benchmark, the Fund's overweight in the biotechnology sector was a detractor. Celldex Therapeutics, a biotechnology company developing drugs for cancer, reported that its brain cancer drug, Rintega, failed in a Phase III study, driving a 76% decline in its stock. Ultragenyx Pharmaceutical, a biotech focused on "ultra-orphan" drugs, declined 44%. Investors sold out of the stock primarily in sympathy with the broader biotech sell-off in the market. While the Fund held onto these stocks because we like the fundamentals of these companies and see value in their drug development pipeline, we do not expect to increase the Fund's weighting in the biotechnology sector.

Winners for the quarter came from various sectors. Quotient Technology (formerly Coupon.com), a company that allows consumer packaged goods companies to digitally distribute coupons, advertising and trade promotions, gained 55%. Quotient reported better-than-expected revenue and earnings for the fourth quarter and continued to show traction winning retailer partners. After a rough 2015, Generac, a manufacturer of standby power generators, rebounded in the first quarter, gaining 24%, as fourth quarter numbers topped expectations. Polaris Industries, a provider of leisure vehicles and related products, gained 17% as the market responded favorably to the company's

announcement of a large share repurchase program, and on fourth quarter results that exceeded marketplace estimates.

We have been working to reposition the Fund to provide improved performance. We added 25 new names to the Fund during the quarter and sold 52 positions, reflecting a pruning of lower-conviction, sub-scale positions. This is more new names added to the Fund in a quarter than in any other quarter in the past five years. We believe that our new idea generation is strong, and our analysts are busy.

What are we focusing on as we consider new stocks? In a market where many companies' base businesses are highly priced given low interest rates, we think one of the best sources of relative value in the market today is the ability to reinvest capital at high rates of return, and this is a characteristic of many of the stocks that we've added. The average estimated return on equity (ROE)* of the 25 stocks that we added in the quarter was 22% for 2016, which compares favorably to the Fund's 14% average estimated ROE prior to the addition of the new names. In addition to looking for companies that have high rates of return, we are also focusing on industry leaders that have shown consistent track records over time and that have future growth potential. We believe the higher quality portfolio that has resulted from our repositioning efforts should bring improved results going forward.

*Return on Equity measures a corporation's profitability by revealing how much profit it generates with the money shareholders have invested.

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.

4

COLUMBIA ACORN® FUND

AT A GLANCE

Total Net Assets of the Fund:
$6.4 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 March 31, 2016

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 March 31, 2016

	1st quarter			1 year			5 years			10 years			Life of Fund
Class Z (6/10/70 inception)		-2.69	%		-7.88	%		6.12	%		5.60	%		14.06	%
Class A (10/16/00 inception)
without sales charge		-2.78			-8.18			5.81			5.29			13.69
with sales charge		-8.39			-13.45			4.57			4.67			13.54
Russell 2500 Index*		0.39			-7.31			8.58			6.47			N/A

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

*The Fund's primary benchmark. Please see Page 24 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 3/31/16

Top 10 Holdings

as a percentage of net assets, as of 3/31/16

1.	Align Technology Invisalign System to Correct Malocclusion (Crooked Teeth)	2.8	%
2.	Expeditors International of Washington International Freight Forwarder	2.2	%
3.	Ansys Simulation Software for Engineers & Designers	1.6	%
4.	Ultimate Software Human Capital Management Systems	1.6	%
5.	Robert Half International Temporary & Permanent Staffing in Finance, Accounting & other Professions	1.6	%
6.	Vail Resorts Ski Resort Operator & Developer	1.6	%
7.	EdR Student Housing	1.5	%
8.	Jones Lang LaSalle Real Estate Services	1.5	%
9.	Polaris Industries Leisure Vehicles & Related Products	1.5	%
10.	VWR Distributor of Lab Supplies	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.

5

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.

Columbia Acorn International Class Z shares ended the first quarter of 2016 up 0.13%, while the Fund's new primary benchmark, the MSCI ACWI Ex USA SMID Cap Index (Net), gained 1.03%. The Fund's underweight position and stock selection in the materials sector detracted from relative performance, as did underperformance of Fund stocks in the Asia ex Japan region.

International equities displayed a similar level of volatility as the U.S. equity markets in the first quarter. Divergent central bank policy, geopolitical risk and terrorist attacks, declining oil prices, and concerns about emerging markets were key themes, especially in January. In February, however, the investment backdrop began to shift in a more positive direction, as the U.S. Federal Reserve indicated that it would take a more gradual approach to raising rates, while both the European Central Bank (ECB) and the Bank of Japan announced negative interest rate policies designed to spur growth.

The Bank of Japan's move to negative rates was a surprise and put downward pressure on Japanese government bond yields. As a result, Japanese real estate investment trusts (REITs) outperformed substantially, driven by demand from yield-hungry investors, while banks and insurers underperformed due to fears of significant compression of net interest spreads (i.e., the difference in their borrowing and lending rates). As we've seen in Europe over the past year, negative interest rates depress the profitability of many financial institutions, since they are unable to pass these costs onto depositors already earning close to 0%. At the end of the quarter, the Fund's main exposure to financials in Europe was through Spanish stock exchange Bolsas y Mercados Españoles and Swiss private markets asset management company Partners Group, neither of which operate spread lending business models. We see a particular opportunity in Japan, where the financials sell-off fails to adequately discount differences in business models. We believe high-yield consumer lending companies, such as Japanese regional bank Suruga Bank and Aeon Financial Service, a diversified consumer-related finance company in Japan, should be less affected by or even benefit from negative rates, as their borrowers are less rate sensitive and funding costs could decline along with overall interest rates. Japanese ATM operator Seven Bank, which collects transaction fees from ATMs installed in convenience stores, does not have a large lending operation, instead using deposits to fund working capital needs. We expect Seven Bank to be a beneficiary as funding costs decline. During the quarter, we added to select positions in Japanese financial stocks as valuations became very attractive,

focusing on names that should benefit or see limited downside from the negative interest rate policy.

We continued to focus the Fund in the quarter by reducing the number of holdings from 179 to 141. As part of this effort, we are also concentrating Fund assets in our highest conviction names to increase the impact these larger positions will have on overall portfolio performance. At quarter end, the top 15 names represented over 20% of the value of the Fund, while a year ago that number was 14%. As an example, we increased the Fund's position in Novozymes, a Danish maker of industrial enzymes, from 1.2% at the beginning of the period to 2.1% at quarter end, making it the Fund's second largest position. We have owned Novozymes for many years and hold it as part of our "game changers" theme, which includes companies that have the potential to transform an industry through innovation, in this case, the long-term substitution of chemicals with enzymes.

The Fund's top-contributing stock in the quarter was Canada's CCL Industries, a global label converter, which gained 18% following its acquisition of U.S.-based Checkpoint Solutions, a maker of anti-theft label systems. We believe the market expects that CCL will be able to extract significant cost and revenue synergies from this move, and that management guidance may be conservative. Rona, a Canadian home improvement retailer, was also strong in the quarter, gaining 90% following the February announcement that it was being acquired by Lowe's. We sold the Fund's position in the stock on the news. On the downside, Wirecard, a German provider of online payment processing and risk management services, fell 24% on allegations of criminal misconduct published by an anonymous and previously unheard of research organization. We believe the allegations are without merit and added to the position on the downturn. IHI, a Japanese industrial conglomerate, fell 49% in the quarter, as word reached the market that several of its projects in shipbuilding and overseas plant construction were exceeding budget estimates, and IHI's profitability drastically deteriorated. We sold the Fund's position in the stock.

In the first quarter, many of the faster growing, momentum-driven stocks that led the market during 2015 were laggards. We welcome the return of volatility to the marketplace, as we believe deep fundamental research can add more value when there is greater price dispersion and attentiveness to valuation.

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.

6

COLUMBIA ACORN INTERNATIONAL®

AT A GLANCE

Total Net Assets of the Fund:
$6.2 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 International® Class Z Shares

September 23, 1992 (Fund inception) through March 31, 2016

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 International at inception appreciated to $15,870 on May 31, 1994, the inception date of the MSCI ACWI Ex USA SMID Cap Index (Net). For comparison with the MSCI ACWI Ex USA SMID Cap Index (Net), we assigned the index the same value as the Fund at index inception.

Average Annual Total Returns for period ended March 31, 2016

	1st quarter			1 year			5 years			10 years			Life of Fund
Class Z (9/23/92 inception)		0.13	%		-5.31	%		3.60	%		5.16	%		10.22	%
Class A (10/16/00 inception)
without sales charge		0.05			-5.58			3.28			4.82			9.80
with sales charge		-5.69			-11.00			2.07			4.20			9.53
MSCI ACWI Ex USA SMID Cap Index (Net)*		1.03			-2.46			2.05			3.37			N/A
S&P Global Ex-U.S. Between $500M® and $5B		1.73			-2.83			2.58			4.49			7.94

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

*The Fund's primary benchmark effective January 1, 2016. Please see Page 24 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 3/31/16

Top 10 Holdings

as a percentage of net assets, as of 3/31/16

1.	CCL Industries (Canada) Global Label Converter	2.2	%
2.	Novozymes (Denmark) Industrial Enzymes	2.1	%
3.	Rightmove (United Kingdom) Internet Real Estate Listings	1.7	%
4.	Partners Group (Switzerland) Private Markets Asset Management	1.6	%
5.	Trelleborg (Sweden) Manufacturer of Sealing, Dampening & Protective Solutions for Industry	1.5	%
6.	Wirecard (Germany) Online Payment Processing & Risk Management	1.4	%
7.	Unibet (Sweden) European Online Gaming Operator	1.4	%
8.	Geberit (Switzerland) Plumbing Systems	1.4	%
9.	Hexagon (Sweden) Design, Measurement & Visualization Software & Equipment	1.3	%
10.	Aalberts Industries (Netherlands) Flow Control & Heat Treatment	1.2	%

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

7

COLUMBIA ACORN USA®

IN A NUTSHELL

Matthew A. Litfin Lead Portfolio Manager	William J. Doyle 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. 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 USA Class Z shares fell 6.04% in the first quarter of 2016, underperforming the 1.52% decline of its primary benchmark, the Russell 2000 Index. Poor stock selection, especially in software and some biotechnology names, was the main reason for the Fund's relative underperformance. The Fund was overweight versus the benchmark in both of these industry sub-sectors. In general, stocks rebounded in the final month of the quarter after a weak start to the year. Within the Russell 2000, utilities and telecommunication services stocks led returns, while health care and energy stocks had the biggest declines. Value stocks solidly outpaced growth stocks across all three major market cap ranges, and mid- and large-cap stocks outperformed small-cap stocks.

The worst detractor from performance in the quarter was SPS Commerce, a provider of supply chain management software that is delivered via the web. A disruption in its sales force caused SPS to set 2016 growth guidance below market expectations, and led to a 40% decline in its stock. We will continue to monitor their results.

In the biotechnology sector, Celldex Therapeutics, a cancer drug developer, fell 78% after its brain cancer drug, Rintega, failed in a Phase III trial. Orphan drug developer Ultragenyx Pharmaceutical fell 44%, declining with the general sell-off in biotechnology stocks in the quarter. Understanding that volatility is inherent in the sector, we roughly maintained the Fund's weight in biotechnology names. This is one of a decreasing number of industries in which the United States has a comparative advantage over other nations, and the Fund has enjoyed significant upside from exposure to biotechnology names in the past.

Among the Fund's top contributors in the quarter, Toro, a manufacturer of turf maintenance equipment, gained 18% on positive earnings news. ExlService Holdings, a provider of business process outsourcing services, gained 14% on quarterly results that beat expectations and on a favorable outlook for 2016. Our third strongest contributor to performance was Zoës Kitchen, a restaurant chain that offers fast, fresh Mediterranean-inspired food. Up 36% in the quarter, the company reported an increase in the number of customers coming to its restaurants, which are growing rapidly in the Southeast and beyond.

Zoës was one of 30 new names added to the portfolio in the quarter, a new-name total matched in only one other quarter during the life of the Fund. We sold 45 positions over the three-month period, reflecting a pruning of lower-conviction, sub-scale positions. As we considered new

names for the Fund, we focused on companies with high rates of return, that are industry leaders with significant future growth potential, and that can reinvest new capital at above-average rates of return. Together, the average estimated return on equity (ROE)* of the Fund's new names was 17% for 2016, which tops the 14% average ROE of the Fund's portfolio prior to the addition of these new holdings. We believe this focus on adding higher quality names to the Fund will improve relative returns as we move forward. We intend to continue finding interesting new ideas for the Fund and are optimistic about the outlook for small-cap stocks. Small caps today are as inexpensive as they have been relative to large caps in the last decade,^† and we believe they offer better growth potential in an environment where profitable growth can be hard to find.

*Return on Equity measures a corporation's profitability by revealing how much profit it generates with the money shareholders have invested.

^†Small cap versus large cap data based on Russell 2000 Index and S&P 500 Index performance.

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.

8

COLUMBIA ACORN USA®

AT A GLANCE

Total Net Assets of the Fund:
$689.7 million

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 USA® Class Z Shares

September 4, 1996 (Fund inception) through March 31, 2016

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 March 31, 2016

	1st quarter			1 year			5 years			10 years			Life of Fund
Class Z (9/4/96 inception)		-6.04	%		-11.83	%		6.03	%		4.81	%		9.66	%
Class A (10/16/00 inception)
without sales charge		-6.12			-12.09			5.76			4.53			9.30
with sales charge		-11.54			-17.15			4.51			3.91			8.97
Russell 2000 Index*		-1.52			-9.76			7.20			5.26			7.78

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

*The Fund's primary benchmark. Please see Page 24 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 3/31/16

Top 10 Holdings

as a percentage of net assets, as of 3/31/16

1.	Toro Turf Maintenance Equipment	2.6	%
2.	Drew Industries RV & Manufactured Home Components	2.3	%
3.	Cavco Industries Manufactured Homes	2.0	%
4.	Mettler-Toledo International Laboratory Equipment	2.0	%
5.	VWR Distributor of Lab Supplies	1.7	%
6.	HealthSouth Inpatient Rehabilitation Facilities & Home Health Care	1.6	%
7.	ExlService Holdings Business Process Outsourcing	1.5	%
8.	Ansys Simulation Software for Engineers & Designers	1.5	%
9.	Colliers International Group Real Estate Services	1.5	%
10.	AMN Healthcare Services Temporary Healthcare Staffing	1.5	%

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.

9

COLUMBIA ACORN INTERNATIONAL SELECT^SM

IN A NUTSHELL

Stephen Kusmierczak 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.

Columbia Acorn International Select Class Z shares fell 1.90% in the first quarter of 2016, underperforming the 0.38% decline of the Fund's new primary benchmark, the MSCI ACWI Ex USA Index (Net). Within this select Fund, the underperformance of two of its larger positions was the primary cause of the relative lag in the quarter. In general, international markets had a volatile start to 2016. January saw significant declines on concerns around diverging central bank policies, declining oil prices and the outlook for emerging markets. In February, the market took a more positive turn on news that the U.S. Federal Reserve would take a gradual approach to raising U.S. interest rates, while both the European Central Bank (ECB) and the Bank of Japan announced negative interest rate policies designed to spur growth.

On the upside in the quarter, Canadian label maker CCL Industries announced the acquisition of U.S.-based Checkpoint Solutions, a maker of anti-theft label systems. We believe the market expects that CCL will be able to extract significant cost and revenue synergies from this acquisition, and that guidance may be conservative. Its stock gained 17% in the quarter. Partners Group, a Swiss investment manager focused on private equity, infrastructure, and real estate, gained 12% in the quarter after reporting a strong finish to the year. Fundraising from new and existing clients continues to exceed expectations, and margins have been buoyed by performance fees and good cost control.

The Fund's worst detractors in the quarter included Wirecard, a German provider of online payment processing and risk management services. Wirecard fell 23% in the quarter on allegations of criminal misconduct published by an anonymous and previously unheard of research organization. We believe the allegations are without merit and added to the position on the downturn. Sony Financial Holdings, a Japanese company offering life insurance, assurance and internet banking services, fell 26% in the quarter. The Bank of Japan's negative interest rate policy put downward pressure on Japanese government bond yields. As a result, banks and insurers underperformed due to fears of significant compression of net interest spreads (i.e., the difference in their borrowing and lending rates). Sony Financial Holdings fell victim to this decline, as a majority of its earnings come from the life insurance business. However, because Sony's investment portfolio has very long maturity periods, we believe that short-term volatility caused by the interest rate change should not have a significant impact. We added to Sony Financial's position on the decline, as we believe that the stock is attractively valued. Together, these two stocks represented more than

6% of Fund assets at quarter end and took nearly 2% away from the Fund's performance. In a portfolio of only 39 names, the impact of a single holding's performance is much greater, as we saw this quarter.

During the quarter, we completed the majority of the repositioning that we have been doing in the Fund. We sold out of 11 positions in the quarter and added five new names. The new names were mainly names we've covered and held in other Columbia Acorn Funds. Two of the larger positions were Rightmove, a UK provider of real estate listings, and Airports of Thailand, an airport operator in Thailand. In both cases, we believe the superior returns on capital they achieve to be sustainable. Rightmove's very asset-light business model is feeding on network effects, generating high operating margins, cash-flow conversion and shareholder returns. Airports of Thailand is benefiting from sustained double-digit growth in air travel from Asia, boosting revenues, margins and the return on capital.

Across the international funds that we manage at Columbia Wanger Asset Management, we have also added exposure to the budget airline space. We believe that the superior operating mechanics of budget airlines will continue to disrupt air travel in Europe, as the incumbent airlines deal with a restive labor force, inflexible route planning and overcapacity. Ryanair, the Irish market leader in the sector, was added in the quarter and gives the Fund exposure to this disruptive dynamic.

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.

10

COLUMBIA ACORN INTERNATIONAL SELECT^SM

AT A GLANCE

Total Net Assets of the Fund:
$119.6 million

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 International Select^SM Class Z Shares

November 23, 1998 (Fund inception) through March 31, 2016

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 International Select at inception appreciated to $17,309 on December 31, 2000, the month-end of the inception date of the MSCI ACWI Ex USA Index (Net). For comparison with the MSCI ACWI Ex USA Index (Net), we assigned the index the same value as the Fund at month-end of the index inception date.

Average Annual Total Returns for period ended March 31, 2016

	1st quarter			1 year			5 years			10 years			Life of Fund
Class Z (11/23/98 inception)		-1.90	%		-4.32	%		2.26	%		4.64	%		7.95	%
Class A (10/16/00 inception)
without sales charge		-2.02			-4.63			1.94			4.30			7.60
with sales charge		-7.64			-10.10			0.74			3.69			7.23
MSCI ACWI Ex USA Index (Net)*		-0.38			-9.19			0.31			1.94			N/A
S&P Developed Ex-U.S. Between $2B and $10B® Index		0.84			-0.74			4.00			3.71			7.15

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

*The Fund's primary benchmark effective January 1, 2016. Please see Page 24 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 3/31/16

Top 10 Holdings

as a percentage of net assets, as of 3/31/16

1.	CCL Industries (Canada) Global Label Converter	5.5	%
2.	Novozymes (Denmark) Industrial Enzymes	5.0	%
3.	Partners Group (Switzerland) Private Markets Asset Management	4.4	%
4.	Wirecard (Germany) Online Payment Processing & Risk Management	3.6	%
5.	Telefonica Deutschland (Germany) Mobile & Fixed-line Communications in Germany	3.2	%
6.	Aeon Mall (Japan) Suburban Shopping Mall Developer, Owner & Operator	3.0	%
7.	Eutelsat (France) Fixed Satellite Services	3.0	%
8.	KDDI (Japan) Mobile & Fixed Line Communication Service Provider in Japan	3.0	%
9.	Amcor (Australia) Global Leader in Flexible & Rigid Packaging	2.8	%
10.	IAG (Australia) General Insurance Provider	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.

11

COLUMBIA ACORN SELECT^SM

IN A NUTSHELL

David L. Frank Co-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 first quarter of 2016 down 0.33%, underperforming the 3.78% gain of the Fund's primary benchmark, the S&P MidCap 400 Index. Within this select Fund, stock-specific declines were largely to blame for the quarter's lag versus the benchmark. We also saw investors move toward more defensive, high-yielding sectors like utilities in the quarter, which is an area we do not have exposure to in the Fund, but that performed well in the benchmark.

Two of the Fund's industrial names rebounded in the quarter. Up 24%, Generac, a manufacturer of standby power generators, reported better-than-expected earnings numbers and offered a positive outlook for 2016. Nordson, a maker of dispensing systems for adhesives and coatings, has struggled against U.S. dollar strength, as 80% of its business is in non-U.S. markets. A weaker dollar and company reports of increased orders in the first months of the year drove an 18% gain in the stock in the quarter. Polaris Industries, a maker of leisure vehicles and related products, gained 15% in the Fund, as the market responded favorably to the company's announcement of a large share repurchase program, and on fourth quarter results that exceeded marketplace estimates.

On the downside, Bankrate, a provider of internet advertising for the insurance, credit card and banking markets, retraced fourth quarter gains, falling over 30% in the first quarter on concerns around increased competition from Google. Given the uncertain competitive environment for Bankrate, we sold the stock. Blackhawk Network, a third-party distributor of prepaid content like gift cards, fell 26%. The company announced an earnings miss driven by changes at the retailer level that have negatively impacted its business. We sold the Fund's position in the stock. SEI Investments, a provider of mutual fund administration and investment management services, was a strong performer in 2015 but fell 24% in the first quarter. SEI has been a long-term holding in the Fund but reports of slower growth and increasing expenses, as well as lowered 2016 expectations, led us to sell the stock in the quarter. Union Agriculture Group, a farmland operator in Uruguay, continued its downward trend, falling 30% in the quarter.

We added eight new stocks to the Fund in the quarter and sold 12 positions, three of which are mentioned above. Among the new names, HRG, a holding company primarily consisting of two publicly traded companies (Spectrum Brands and Fidelity & Guaranty Life) ranked as the Fund's fifth largest position at quarter end. We like Spectrum Brands' operational strategy and view growth prospects favorably, and we feel HRG provides a better value than Spectrum Brands. Liberty Global, an owner of cable TV franchises outside the United States, was also added to the

Fund's top 10 positions in the quarter. Liberty Global boasts a strong and expanding cable infrastructure in Europe and the United Kingdom, where cable adoption is lower than in the United States. As we made adjustments to the portfolio in the quarter, we added some more defensive names and moved away from more speculative positions.

As a relatively new management team for the Fund, we actively refashioned holdings in the first quarter. We view these moves as consistent with the Fund's high-quality, growth-at-a-reasonable-price strategy and with our goal of bolstering long-term portfolio results.

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.

12

COLUMBIA ACORN SELECT^SM

AT A GLANCE

Total Net Assets of the Fund:
$369.6 million

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 Select^SM Class Z Shares

November 23, 1998 (Fund inception) through March 31, 2016

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 March 31, 2016

	1st quarter			1 year			5 years			10 years			Life of Fund
Class Z (11/23/98 inception)		-0.33	%		-3.49	%		5.77	%		5.33	%		9.46	%
Class A (10/16/00 inception)
without sales charge		-0.36			-3.74			5.47			5.03			9.12
with sales charge		-6.09			-9.28			4.23			4.41			8.75
S&P MidCap 400® Index*		3.78			-3.60			9.52			7.78			9.91

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

*The Fund's primary benchmark. Please see Page 24 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 3/31/16

Top 10 Holdings

as a percentage of net assets, as of 3/31/16

1.	LKQ Alternative Auto Parts Distribution	5.1	%
2.	EdR Student Housing	4.2	%
3.	Nordson Dispensing Systems for Adhesives & Coatings	4.2	%
4.	Align Technology Invisalign System to Correct Malocclusion (Crooked Teeth)	4.1	%
5.	HRG Group Holding Company	4.1	%
6.	Ametek Aerospace/Industrial Instruments	4.0	%
7.	Crown Castle International Communications Towers	4.0	%
8.	Generac Standby Power Generators	3.7	%
9.	Liberty Global Series A Cable TV Franchises Outside of the United States	3.7	%
10.	Vail Resorts Ski Resort Operator & Developer	3.6	%

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.

13

COLUMBIA THERMOSTAT FUND^SM

IN A NUTSHELL

David L. Frank Co-Portfolio Manager*	Christopher J. Olson Co-Portfolio Manager

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

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.

Class Z shares of Columbia Thermostat Fund, our fund of funds, ended the first quarter of 2016 up 1.84%. This compares to a 1.35% gain of the Fund's primary equity benchmark, the S&P 500® Index, and a 3.03% gain of the Fund's primary debt benchmark, the Barclays U.S. Aggregate Bond Index. The Fund's custom 50/50 Blended Benchmark gained 2.28% in the quarter.

The Fund's equity portfolio had a weighted average loss of 0.62% in the first quarter, due largely to the 11.69% decline of Columbia Select Large Cap Growth Fund. The leading equity performer in the quarter was Columbia Dividend Income Fund, which gained 3.35%. The bond portion of the Fund had a weighted average gain of 1.83% for the period, led by the 2.92% gain of Columbia Total Return Bond Fund. All of the underlying bond funds offered positive performance in the quarter.

The Fund hit four reallocation triggers in the first quarter. The Fund increased stock exposure in January and February, as the markets lagged, and decreased exposure in March, as equity markets came back.

During the first quarter of 2016, we conducted the periodic review of underlying funds called for by Columbia Thermostat Fund's prospectus. As a result, the following changes will be effective with the Fund's May 1, 2016 prospectus:

•  Columbia Income Opportunities Fund's weighting will decrease from 20% to 10% of the bond portfolio.

•  Columbia U.S. Treasury Index Fund, a U.S. Treasury notes/bonds fund, will be added with a 10% weight in the bond portfolio.

•  The stock/bond allocation table levels will be revised up 25 points. For example, the Fund will move to 10% stocks at an S&P 500 level over 2,250, up from 2,225. The Fund will move to 90% stocks at a level of 1,125 or less, up from 1,100.

We applaud the managers of Columbia Income Opportunities Fund for generating good historical returns while assuming only moderate risks. However, the Fund tends to correlate with stocks somewhat more than we would prefer. Replacing half of that position with Columbia U.S. Treasury Index Fund should result in less risk in Columbia Thermostat Fund.

*  After 38 years at Columbia Wanger Asset Management, Charles P. McQuaid retired on April 29, 2016. Effective May 1, 2016, David L. Frank became a co-portfolio manager of the Fund, joining current co-portfolio manager Christopher J. Olson.

Results of the Funds Owned in Columbia Thermostat Fund

as of March 31, 2016

Stock Funds

Fund	Weightings in category			1st quarter performance
Columbia Acorn International, Class I		20	%		0.18	%
Columbia Contrarian Core Fund, Class I		20	%		0.62	%
Columbia Dividend Income Fund, Class I		20	%		3.35	%
Columbia Acorn Fund, Class I		10	%		-2.68	%
Columbia Acorn Select, Class I		10	%		-0.33	%
Columbia Large Cap Enhanced Core Fund, Class I		10	%		0.38	%
Columbia Select Large Cap Growth Fund, Class I		10	%		-11.69	%
Weighted Average Equity Loss		100	%		-0.62	%

Bond Funds

Fund	Weightings in category			1st quarter performance
Columbia Short Term Bond Fund, Class I		40	%		1.01	%
Columbia Total Return Bond Fund, Class I**		20	%		2.92	%
Columbia Income Opportunities Fund, Class I		20	%		2.77	%
Columbia U.S. Government Mortgage Fund, Class I		20	%		1.39	%
Weighted Average Income Gain		100	%		1.83	%

**Effective February 19, 2016, Columbia Intermediate Bond Fund changed its name to Columbia Total Return Bond Fund.

Columbia Thermostat Fund Rebalancing in the First Quarter

January 7, 2016	30% stocks, 70% bonds
January 11, 2016	35% stocks, 65% bonds
February 12, 2016	40% stocks, 60% bonds
March 14, 2016	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.

14

COLUMBIA THERMOSTAT FUND^SM

AT A GLANCE

Total Net Assets of the Fund:
$1.1 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 Thermostat Fund^SM Class Z Shares

September 25, 2002 (Fund inception) through March 31, 2016

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 March 31, 2016

	1st quarter			1 year			5 years			10 years			Life of Fund
Class Z (9/25/02 inception)		1.84	%		0.67	%		6.39	%		5.88	%		7.40	%
Class A (3/3/03 inception)
without sales charge		1.75			0.40			6.12			5.62			7.12
with sales charge		-4.08			-5.38			4.88			4.99			6.65
S&P 500® Index*		1.35			1.78			11.58			7.01			9.27
Barclays U.S. Aggregate Bond Index*		3.03			1.96			3.78			4.90			4.51

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

*The Fund's primary benchmarks. Please see Page 24 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 3/31/16

Portfolio Weightings

as a percentage of assets in each investment category, as of 3/31/16

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 Total Return Bond Fund, Class I*	20	%
Columbia Income Opportunities Fund, Class I	20	%
Columbia U.S. Government Mortgage Fund, Class I	20	%

*Effective February 19, 2016, Columbia Intermediate Bond Fund changed its name to Columbia Total Return Bond Fund.

15

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.

Columbia Acorn Emerging Markets Fund Class Z shares fell 0.58% in the first quarter of 2016, underperforming the Fund's new benchmark, the MSCI Emerging Markets SMID Cap Index (Net), which gained 3.06%. As global concerns about China continued into 2016, the Fund's underweight in this market was a plus, but our Chinese stocks underperformed, hurting relative returns. Other heavily weighted markets in the Fund, including India and Korea, were overall detractors, while the Fund's underweight and stock selection in Taiwan benefited performance.

The Fund's lesser exposure to rebounding, commodity-driven markets also detracted from relative performance, as most of these markets saw their currencies strengthen against the U.S. dollar (USD) in the quarter. The Brazilian real, for example, strengthened 9% on positive rate news coming from the United States, the improved prospects for commodity prices, and on positive local reaction to the likely impeachment of Brazilian President Rousseff. The Brazilian stock market reacted favorably, and the Brazilian portion of the Fund's benchmark gained 25% during the quarter in USD. The South African rand and Malaysian ringgit also rebounded in the quarter, helping to boost returns for USD-based investors. While we were pleased to see the positive turn in these markets, we see little evidence of improvements in their structural issues, such as high dependency on commodity exports and weaker domestic manufacturing industries.

Fund performance benefited from our stock selection in the telecommunications space, where the Fund holds an eclectic mix of names. The Fund's five telecom stocks come from four different markets with varying industry focus, such as communications towers, mobile operations, and broadband and cable television service. During the quarter, we saw a strong rally in commodities as investors increased speculation on a possible recovery in Chinese demand, but we have historically been underweight this sector because of its largely undifferentiated business models and low returns on capital. The Fund's underweight in materials and utilities detracted from performance, and the positive impact of the Fund's overweight in energy was diluted by poor stock performance in the sector.

China continues to be an important area of investment for the Fund. Stock valuations in China are compelling and appear to be pricing in slower growth and a devaluation of the renminbi. We are maintaining our focus on unique businesses supported by structural tailwinds in China. For example, Silergy is a provider of analog and mixed digital integrated circuits operating in China. Silergy is uniquely

positioned—through a combination of western trained management, technical expertise and local relationships—to capitalize on the secular trends of increased information technology product manufacturing and consumption in China, and the Chinese government's strong desire to build a self-sufficient local semiconductor ecosystem. Silergy's stock, which is listed in Taiwan, was a top contributor to performance in the quarter, gaining 33%.

Another top-contributing stock in the quarter was South African asset manager Coronation Fund Managers. Its stock rose 47%, recovering from multi-year lows after fears of fund outflows moderated, and investors became attracted to the company's relatively high dividend yield. On the downside, Zee Entertainment Enterprises, an Indian programmer of pay television content, fell 11%, cooling after significantly outpacing the Indian market in 2015 even though advertising and subscription revenue growth remained robust. Ginko International, a contact lens maker in China that is also listed in Taiwan, fell 25% in the quarter, as investors sold Taiwanese stocks with large Chinese exposure due to concerns about the outlook for China's growth.

While growth rates in the global economy decelerate, many emerging countries are still delivering faster growth. In particular, disposable income growth should exceed that of GDP in key emerging countries due to favorable demographics and middle class growth, as a result of productivity improvements. Our emphasis on companies benefiting from such structural tailwinds remains unchanged. We believe that long-term investors should benefit from investing in high-quality businesses with good growth prospects at reasonable valuations, which can be found within our emerging market universe.

Effective February 1, 2016, Columbia Acorn Emerging Markets Fund re-opened to new investors and new accounts. While size will always be monitored closely in this Fund, we believe that we have capacity to add assets. We also believe the opportunities and current investment environment in most emerging markets provide a compelling entry point for new investors.

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.

16

COLUMBIA ACORN EMERGING MARKETS FUND^SM

AT A GLANCE

Total Net Assets of the Fund:
$184.0 million

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 Emerging Markets Fund^SM Class Z Shares

August 19, 2011 (Fund inception) through March 31, 2016

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 March 31, 2016

	1st quarter			1 year			Life of Fund
Class Z (8/19/11 inception)		-0.58	%		-17.81	%		1.41	%
Class A (8/19/11 inception)
without sales charge		-0.59			-18.02			1.13
with sales charge		-6.26			-22.74			-0.16
MSCI Emerging Markets SMID Cap Index (Net)*		3.06			-10.23			-1.46
S&P Emerging Markets Between $500M and $5B® Index		4.73			-10.71			0.32

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

*The Fund's primary benchmark effective January 1, 2016. Please see Page 24 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 3/31/16

Top 10 Holdings

as a percentage of net assets, as of 3/31/16

1.	Zee Entertainment Enterprises (India) Indian Programmer of Pay Television Content	4.0	%
2.	ModeTour Network (Korea) Travel Services	2.8	%
3.	Link Net (Indonesia) Fixed Broadband & Cable TV Service Provider	2.8	%
4.	Far EasTone Telecom (Taiwan) Mobile Operator in Taiwan	2.7	%
5.	MNC Sky Vision (Indonesia) Satellite Pay TV Operator in Indonesia	2.7	%
6.	Samui Airport Property Fund (Thailand) Thai Airport Operator	2.5	%
7.	Koh Young Technology (Korea) Inspection Systems for Printed Circuit Boards	2.5	%
8.	NewOcean Energy (China) Southern China Liquefied Petroleum Gas Distributor	2.4	%
9.	Grupo Aeroportuario del Sureste (Mexico) Mexican Airport Operator	2.4	%
10.	Hoteles City Express (Mexico) Budget Hotel Operator in Mexico	2.3	%

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.

17

COLUMBIA ACORN EUROPEAN FUND^SM

IN A NUTSHELL

Andreas Waldburg-Wolfegg Co-Portfolio Manager	Stephen Kusmierczak 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.

Columbia Acorn European Fund Class Z shares gained 1.15% in the first quarter of 2016, outperforming the 0.87% decline of the Fund's new primary benchmark, the MSCI AC Europe Small Cap Index (Net). Strong stock selection contributed to the outperformance in most regions, with the Fund's overweight position in the Nordic region helping the most. In the Mediterranean region, the Fund's underweight versus the benchmark and good stock performance also boosted gains.

Within the Nordic region, Recipharm, a Swedish contract developer and manufacturer of pharmaceuticals, was a top contributor to performance, gaining 25% in the quarter. The company has been an aggressive consolidator in Europe and has recently expanded to India and the United States. Management and the company founders remain large owners and have strong incentives to build a sustainable and profitable business. In Finland, specialty paper manufacturer Munksjo gained 16% after it reported solid results in its core décor and release liner businesses, and raised its dividend 20%. Munksjo was the Fund's largest position at quarter end and a strong contributor to performance.

In the Mediterranean region, Prosegur, a Spanish company that provides guarding and cash-in-transit security in Europe and Latin America, enjoyed a recovery in the first quarter, gaining 24%. Last year, the company's exposure to Latin America was a drag on performance, but the stock came back in the period on solid results, strong revenue growth and a positive outlook for 2016.

On the downside, Wirecard, a German online payment processing and risk management company, fell 23% in the quarter and was the Fund's largest detractor. The company faced allegations of criminal misconduct that were published by an anonymous and previously unheard of research organization. We believe the allegations are without merit and added to the position on the downturn. Reversing direction in the quarter, SimCorp, a Danish developer of software for investment managers, fell 20%. SimCorp was one of the best-performing stocks in Denmark last year and suffered from profit-taking in the first quarter. We continue to like the stock and added to the position in the quarter. Based in the Netherlands, Arcadis, a provider of engineering consulting services, fell 32%. We sold the Fund's position in the stock on concerns around new writedowns on a previous acquisition, continued deterioration in its U.S. and emerging markets businesses, and our perception of poor risk controls within the company.

During the quarter, the Fund's underweight exposure to financials, specifically banks, was a positive for performance. We have maintained an underweight in

banks because European Central Bank (ECB) policies have been detrimental to the banking industry. This underweight, specifically in Italian banks, has hurt Fund performance in the past. For example, in Italy in 2015, expectations of bank consolidations enticed investors but failed to materialize because of continued interest rate declines and other macroeconomic concerns. We have been and continue to be bearish on the quality to be found in Italian banks, and were pleased to see our concerns acknowledged by the market in the first quarter. The Fund's overweight in the information technology sector was also a positive in the quarter, but declines in large holdings Wirecard and SimCorp hurt relative stock performance in the sector.

As we consider the European landscape at quarter end, some very large challenges face the continent. We have witnessed three deadly terrorist attacks taking place over 15 months, revealing systemic failures in Europe's security coordination. A British exit from the European Union is a growing possibility, and we believe would be negative for the United Kingdom and the European Union. There is rising anti-EU sentiment across Europe, as seen in recent elections in Scandinavia, Poland, Hungary, the Netherlands, Austria and France. European industry has benefitted enormously from free trade and travel following implementation of the 1985 Schengen accord. Recent terrorist attacks and worries about uncontrolled immigration have caused several states to restrict free personal movement across their borders, while still maintaining the free movement of goods. Long-term and tighter restrictions could eventually increase the costs of trade and travel in Europe.

As we noted last quarter, crisis is not new to Europe, and we have been able to find what we consider to be excellent investment opportunities during periods of uncertainty. Moreover, European small-caps were one of the strongest-performing areas of global equity markets last year and that strength has continued into 2016. We are seeing a generally positive outlook for earnings from companies poised to benefit from a weaker euro and ECB easing, and an overall increase in economic growth that should boost company profits. We remain focused on investing in companies with strong fundamentals, that we believe are industry leaders and that are good stewards of shareholder capital.

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.

18

COLUMBIA ACORN EUROPEAN FUND^SM

AT A GLANCE

Total Net Assets of the Fund:
$65.5 million

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 European Fund^SM Class Z Shares

August 19, 2011 (Fund inception) through March 31, 2016

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 March 31, 2016

	1st quarter			1 year			Life of Fund
Class Z (8/19/11 inception)		1.15	%		1.18	%		10.20	%
Class A (8/19/11 inception)
without sales charge		1.08			0.93			9.91
with sales charge		-4.73			-4.86			8.51
MSCI AC Europe Small Cap Index (Net)*		-0.87			4.60			11.88
S&P Europe Between $500M and $5B® Index		-1.22			3.02			11.85

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

*The Fund's primary benchmark effective January 1, 2016. Please see Page 24 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 3/31/16

Top 10 Holdings

as a percentage of net assets, as of 3/31/16

1.	Munksjo (Finland)† Specialty Paper Maker	3.5	%
2.	Assura (United Kingdom) UK Primary Health Care Property Developer	3.4	%
3.	Rightmove (United Kingdom) Internet Real Estate Listings	3.3	%
4.	Trelleborg (Sweden) Manufacturer of Sealing, Dampening & Protective Solutions for Industry	2.6	%
5.	Wirecard (Germany) Online Payment Processing & Risk Management	2.6	%
6.	Unibet (Sweden) European Online Gaming Operator	2.6	%
7.	Aurelius (Germany) European Turnaround Investor	2.5	%
8.	Recipharm (Sweden) Contract Development Manufacturing Organization	2.5	%
9.	Tikkurila (Finland) Decorative & Industrial Paint in Scandinavia, Central & Eastern Europe	2.5	%
10.	SimCorp (Denmark) Software for Investment Managers	2.3	%

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

19

SQUIRREL CHATTER: PEAK EVERYTHING

Doom caused by depletion of natural resources

There have always been doomsayers. Richard Heinberg's Peak Everything, published in 2007, was a gloom-and-doom book primarily based on the premise that petroleum production was peaking. Heinberg noted that fossil fuels accounted for 85% of the world's energy supply and facilitated much of food production and extraction of other resources.¹

Due to an anticipated drop in oil production and depletion of other resources, Heinberg predicted that worldwide economic activity would begin to decline in 2008 and would not return to 2007 levels anytime soon, if ever. Heinberg advocated for an "enormous collective effort...coordinated presumably by government...educating and motivating" people to respond with "many years of hard sacrifice."²

Stating that "technology cannot solve the underlying dilemma we face as a result of our application of fossil fuels...," Heinberg advocated "a radical reduction of fossil fuel inputs to agriculture, accompanied by an increase in labor inputs..." He wrote that Cuba in the early 1990s serves as an example, as it switched to a labor-intensive, organic mode of production when the Soviet Union collapsed and no longer provided cheap oil. Cubans involuntarily adopted a largely vegetarian diet and some were forced to work on farms. He added that a minimum of 40 million additional farmers will be needed in America, as oil and gas availability decline.³

Prosperity while nature rebounds due to demographics and technology

Two thought leaders rebut Heinberg, painting a vastly different and much more prosperous future. In The End of Doom: Environmental Renewal in the Twenty-first Century, Ronald Bailey lists numerous previous depletion scares. The most recent, Hubbert's Peak, was based on the timing and size of oilfield discoveries and calculations of their combined decline rates. Production was to peak in late 2005 and decline forever. Yet cumulative production has far exceeded previous estimates of known oil reserves, and known reserves have actually been growing! With hydraulic fracturing and horizontal drilling, recovery rates are up in

conventional fields and shale oil and gas technology substantially increases reserves. Experts now see oil production plateauing at 110 million barrels per day in 2035, far above Heinberg's 82 million "peak" of 2005, and production at that rate for 40 years.⁴

Jesse Ausubel, in his essay titled "Nature Rebounds," notes that per capita petroleum usage in the United States peaked around 1970, and he charts data from the U.S. Energy Information Administration suggesting that crude oil consumption in the United States peaked in 2005. Vehicles are more efficient and more people live in cities. Self-driving cars will likely be shared and used more than personal vehicles, resulting in a drop in demand for vehicles. Commercial jets are about 70% more fuel efficient than jets of the 1960s, and further improvements are being introduced.⁵ It will likely take a while for world consumption to peak, but peak oil could be caused by peaking demand rather than supply.

Bailey also writes about changes in preferences when societies become wealthier and technology advances. He notes that high mortality drives high fertility as an offset, resulting in slow population growth. With improved medicine, sanitation and nutrition, population numbers can begin to explode. However, once people believe virtually all their children will survive, and families move to cities where children don't work and women become educated and have access to contraception, birth rates plunge. Since 1970, worldwide fertility has fallen from 4.7 children to 2.45 in 2013 and is continuing to drop. Bailey quotes research concluding that world population will reach about nine billion people by 2050, and will likely stabilize and then decline in the second half of the 21^st century.⁶ Peak population seems likely.

Bailey advocates technology-intensive agriculture, including the use of genetically modified organisms (GMOs). GMO plants began about 80 years ago when seeds were exposed to radiation, chemicals or ultraviolet light in order to change plant DNA. A small percentage of those seeds yielded attractive crops, such as the seedless watermelon, the Ruby Red grapefruit and 3,000 other crops. Some are now marketed as organic. More precise, gene-spliced GMOs were planted beginning in 1996. By 2013, 18 million farmers in 27 countries planted 433 million acres of what are considered biotechnology crops. Yield gains from 1996 to

20

2012 alone saved 300 million acres from being farmed. Pesticide usage dropped nearly 9% and conservation tillage was adopted, reducing topsoil erosion by 1 billion tons annually.⁷

Bailey takes on the anti-GMO crowd head on. He quotes numerous scientific sources who have determined that GMO foods are safe, including researchers who reviewed 1,700 GMO studies. One study that attempted to prove otherwise was retracted. Contrary to accusations by opponents of GMOs, biotech plants don't cause "superweeds" (weeds that become resistant to herbicides). Applying the same herbicide and failing to rotate crops for years allows weeds immune from that herbicide to emerge, whether the crop is biotech or not.⁸ However, Bailey fails to mention risks of biotech foods containing allergens, which are mitigated by approval processes that prevent allergens from being in GMO products approved for human consumption.⁹

Bailey has special wrath for third-world activists who apparently would prefer their countrymen starve rather than eat donated GMO food. For example, Indian activist Vandana Shiva claimed that such donations resulted in Indian disaster victims being used as "guinea pigs" despite the fact that Americans have been eating such food for years. Shiva also blamed farmer suicides on biotech cotton, which nearly doubled production and slashed pesticide use.¹⁰

Emerging technologies are also likely to boost crop yields. Plants are dependent on naturally occurring microbes in soil, and tests indicate that coating seeds with favorable microbes enhances yields.¹¹ Biotech scientists are also exploring ways of activating existing genes in plants that would make them better utilize water and nutrients.

Ausubel agrees that productivity of farmland has skyrocketed. Also, tastes have shifted from beef to chicken and farmed fish, which produce far more protein per pound of feed. And if food waste, currently at about a third of production, can be cut via better technology, further savings would occur. Ausubel argues that these factors, plus slowing population growth, suggest that peak farmland will occur despite improved nutrition. An area the size of India could revert back to nature in about 50 years.

Meanwhile, harvests of trees are shifting from slow growing northern forests to fast growing southern tree plantations. Ausubel wrote that Brazilian eucalyptus plantations annually provide 40 cubic meters of timber, compared with

7.4 in the U.S. southeast and 3.6 in northern areas. Assuming only that plantations in general are twice as productive as natural forests, if 75% of wood were to come from plantations rather than the current 33%, logging of natural forests would halve. In addition, paper is being displaced by technology, as mail, newspapers, magazines and books are delivered to electronic devices. These factors point to peak timberland.

The combination of some farmland reverting back to nature and increasing use of tree plantations has already resulted in reforestation in many parts of the world. Bailey notes that, excluding Brazil and Indonesia, forests of the world have increased about 2% since 1990.¹²

Bailey adds that known mineral reserves are defined as ores currently economically and technically practical to extract, while resources are ores eventually likely to be extracted.¹³ Reserves usually cover a few decades of consumption, spurring some to say that the minerals would subsequently be depleted. Yet miners have no incentive to find new supplies and develop new technologies for production that might be 20 or more years away. The United States Geological Survey estimates resources at well over 100 years of production for most minerals.

Production efficiency has also surged. Bailey cites data from University of Manitoba's Vacliv Smil showing that energy used to produce a ton of steel or synthetic nitrogen fertilizer dropped 80% since the year 1900 and to produce aluminum or cement, fell 70%. Energy to desalinate a gallon of water plunged 90% since 1970, and LED bulbs use about 90% less energy than incandescent bulbs producing the same amount of light. Bailey quotes a study calculating that material intensity per unit GDP in the United States dropped 75% since 1920.¹⁴

Ausubel notes that the economy is becoming dematerialized. A smartphone displaces a camera, film, a photo album, a radio, a tape or CD player, an alarm clock, a compass, a personal navigation device, a Rolodex, a calendar, maps, snail mail, newspapers, magazines, encyclopedias and of course a wired telephone. Also, people moving into cities consume less housing and transportation resources.

Ausubel refers to a study he conducted with Iddo Wernick and Paul Waggoner, which tracked usage of 100 commodities in the United States between 1900 and 2010. Some 36 have peaked in absolute use, with nasty

21

commodities like asbestos and cadmium leading the way. The authors believe another 53 commodities are poised to peak, including electricity, petroleum, cropland and water. Only 11 commodities are likely to see growing demand, including chickens and special metals used in electronics or alloys.

Poor countries tend to tolerate pollution, but Bailey writes that once per capita GDP hits about $10,000, people demand a cleaner environment. China has reached that level and its sulfur dioxide emissions likely peaked in 2006,¹⁵ while its coal consumption may be peaking this year.¹⁶ Peak pollution occurred in the United States decades ago. Bailey cites U.S. Environmental Protection Agency data from 1980 and 2011, which states that GDP rose 128%, vehicle miles 94%, population 37% and energy consumption 26%, while total emissions of six principal air pollutants dropped 63%.¹⁷ As more countries reach middle and upper income status, worldwide pollution should drop. Output of carbon dioxide, which not long ago was labelled a pollutant, more recently peaked in the United States, largely due to plateauing electricity production and a shift from coal to natural gas fired production.¹⁸ Wind and solar power have helped a little and are ramping up quickly.

Oceans are the primary exception to these favorable trends, as fish biomass continues to be depleted. Ausubel notes that 40% of seafood is now raised by aquaculture, and if the upward trend continues oceans can rebound. Bailey believes that almost all environmental problems center in areas that no one owns or has direct responsibility for maintaining, like our oceans. Self-interest drives exploitation of common resources—catch the fish before someone else does, or pollute if there is no direct cost of doing so.¹⁹ Extensions of property rights and responsibilities can solve these sorts of problems.

Bailey agrees that climate change could become a significant problem, though so far the climate has warmed less than 97% of what the Intergovernmental Panel on Climate Change's (IPCC) models predicted. Also, given improvements in efficiency and dematerialization, carbon emissions will increase at predicted rates only if mankind continues to get rich. An IPCC-commissioned study created five scenarios for the year 2100, the middle scenario had the world population peak at 9.6 billion in 2065 and fall to 9.0 billion in 2100. Average income per person would hit $60,000, far above U.S. and world per capita income of

$42,000 and $10,000, respectively, achieved in 2010.²⁰ Bailey notes that much of the world will be more able to afford the cost of climate change mitigation as time goes on.

Bailey also believes that clean energy will become less costly than fossil fuels. He notes that global photovoltaic capacity has grown 10-fold from 2008 to 2016. Levelized cost of solar fell from $323 per megawatt-hour to $72 now, and if current trends continue, will fall to $24 in 10 years. That's cheaper than natural gas powered electricity currently at $33 and coal at $62, but does not cover costs to store solar power when the sun isn't shining. Batteries and other storage methods are improving, and breakthroughs are possible.

In the meantime, Bailey advocates ending government subsidies for fossil fuels, which he wrote cost $544 billion worldwide in 2012. Since nitrogen fertilizers account for most greenhouse gas nitrous oxide emissions, Bailey also advocates ending subsidies for agriculture and fertilizers in order to reduce overuse of fertilizers. Finally, Bailey advocates deployment of nuclear reactors that are impossible to melt down and research on fast-breeder reactors.²¹ Geoengineering should be researched to counteract climate change, should the need arise.

Conclusions and farewell

Long-time readers may remember that past "Squirrel Chatters" have covered many of the issues discussed above. Over the past 11 years, I've written on demographics, agriculture, natural gas from shale, photovoltaic energy and batteries. Population is in fact in a peaking process. Existing technologies are improving at moderate rates, which over time compound into huge gains. Technology breakthroughs have happened occasionally, and the scientific press suggests more are on the horizon.²²

I believe that the biggest risk to the rosy outlook is political. The public's knowledge of science is poor, and media and internet sources are often slanted. A recent editorial in Science magazine lamented the large opinion gap between scientists and the public on such issues as GMOs, vaccinations and global warming. Pressure groups could induce politicians to pass laws prohibiting or inhibiting progress. As I mentioned in my fourth quarter 2015 "Squirrel Chatter," the precautionary principle, which bans anything that might cause harm, would have stopped many of mankind's greatest innovations. Subject to these

22

caveats, I agree with Bailey's statement, "[H]umanity can look hopefully forward in the twenty-first century to an age of environmental renewal."²³

After 38 years, I will have fully retired from Columbia Wanger Asset Management by the time this essay is published. I've enjoyed being a security analyst and portfolio manager, and helping people achieve their financial goals. An additional benefit was being a witness to history, closely monitoring lots of favorable technological advancements and economic developments. I've also enjoyed writing "Squirrel Chatter," as it was a great excuse to do deep dives into interesting subjects and share the knowledge I gained. Thank you for reading and farewell.

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 of Trustees, are subject to change at any time based upon economic, market or other conditions, may differ from views expressed by other Columbia Management associates and the respective parties disclaim any responsibility to update such views. These views may not be relied on as investment advice and, because investment decisions for a Columbia Acorn Fund are based on numerous factors, may not be relied on as an indication of trading intent on behalf of any particular Columbia Acorn Fund.

¹  Richard Heinberg, Peak Everything, Waking Up to the Century of Declines, (British Columbia, Canada, New Society Publishers, 2007), p. 3 & 7.

²  Ibid., p. xv, xxii.

³  Ibid., p. 18, 44 & 55.

⁴  Ronald Bailey, The End of Doom: Environmental Renewal in the Twenty-first Century, (New York, St. Martin's Press, 2015), p. 40-42.

⁵  David P. Hess, "Green Aviation Reality Check," Aviation Week & Space Technology, April 10, 2016.

⁶  Bailey, op. cit., p. 2, 14 & 16.

⁷  Ibid., p. 134-135, 147 & 150.

⁸  Ibid., p. 139, 142, 155-156.

⁹  Charles Xu, "Nothing to Sneeze at: the Allergenicity of GMOs," Science in the News, Harvard University, August 10, 2015. http://sitn.hms.harvard.edu/flash/2015/
allergies-and-gmos/. Accessed on April 20, 2016.

¹⁰  Bailey, op. cit., p. 164.

¹¹  "The BioAg Alliance Readies New Microbial Solution to Improve Corn Harvests," BusinessWire, January 6, 2016. http://www.businesswire.com/news/home/
20160106005940/en/BioAg-Alliance-Readies-Microbial-Solution-Improve-Corn. Accessed on March 18, 2016.

¹²  Bailey, op. cit., xvii.

¹³  Ibid., p. 53.

¹⁴  Ibid., p. 61 & xv.

¹⁵  ibid., p. 60.

¹⁶  "Gluts for punishment, China's industrial excess goes beyond steel," The Economist, April 9, 2016, p. 66.

¹⁷  Bailey, op. cit., p. 60.

¹⁸  Jesse H. Ausubel, "Nature Rebounds," Long Now Foundation Seminar, San Francisco, January 13, 2015, p. 10. http://phe.rockefeller.edu/docs/ Nature_Rebounds.pdf. Accessed on April 19, 2016.

¹⁹  Bailey, op. cit., p. xv.

²⁰  Ibid., p. 180 & 193.

²¹  Ibid., p. 211, 222-223.

²²  Robert F. Service, "Synthetic microbe has fewest genes, but many mysteries," Science, March 25, 2016, p. 1380-1381.

²³  Bailey, op. cit., p. xix.

23

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.

•  MSCI AC Europe Small Cap Index(Net) captures a small-cap representation across 21 markets in Europe. The index covers approximately 14% of the free float-adjusted market capitalization across each market country in Europe.

•  MSCI ACWI ex USA Index (Net) captures a large- and mid-cap representation across 22 of 23 developed market countries (excluding the U.S.) and 23 emerging market countries. The index covers approximately 85% of the global equity opportunity set outside the United States.

•  MSCI ACWI ex USA SMID Cap Index(Net) captures a mid- and small-cap representation across 22 of 23 developed market countries (excluding the U.S.) and 23 emerging market countries. The index covers approximately 28% of the free float-adjusted market capitalization in each country.

•  MSCI Emerging Markets SMID Cap Index(Net) captures a mid- and small-cap representation across 23 emerging market countries. The index covers approximately 29% of the free float-adjusted market capitalization in each country.

•  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 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 22 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, 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. 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.

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

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

24

COLUMBIA ACORN® FUND

MAJOR PORTFOLIO CHANGES IN THE FIRST QUARTER (UNAUDITED)

	Number of Shares
	12/31/15		3/31/16
Purchases
Information
Ansys		912,317		1,138,317
Booz Allen Hamilton		0		2,290,000
Cadence Design Systems		2,722,087		3,476,086
CDW		0		1,233,000
CoreLogic		952,683		1,261,683
Cvent		1,364,000		1,849,000
ExlService Holdings		573,858		629,558
Factset Research Systems		0		319,000
FLIR Systems		1,095,634		1,582,634
Gartner		0		566,000
Global Eagle Entertainment		1,625,994		2,512,994
MA-COM Technology Solutions Holdings		565,500		795,500
Manhattan Associates		0		892,000
Ultimate Software		259,073		524,073
Vantiv		0		1,567,000
Verisign		521,885		782,885
Industrial Goods & Services
Acuity Brands		0		329,000
Axalta Coating Systems		802,000		1,172,000
Celanese		0		734,000
Expeditors International of Washington		1,959,000		2,874,000
International Flavors & Fragrances		0		260,000
Manpower		0		636,000
Stericycle		0		548,000
Toro		620,084		891,230
WABCO Holdings		204,681		326,681
Health Care
Align Technology		2,420,173		2,461,778
Celldex Therapeutics		2,428,687		2,640,414
Dentsply Sirona		519,314		791,444
Fluidigm		879,013		1,806,125
HealthSouth		1,270,314		2,059,989
IDEXX Laboratories		0		927,000
Medivation		0		1,569,000
Mednax		0		661,000
Quintiles Transnational Holdings		0		1,216,000
VWR		1,459,114		3,255,114
West Pharmaceutical Services		0		70,767
Consumer Goods & Services
Choice Hotels		502,751		1,007,751
Domino's Pizza		266,216		370,216
Five Below		333,020		620,000
Liberty TripAdvisor Holdings Class A		1,230,078		1,617,678

	Number of Shares
	12/31/15		3/31/16
Polaris Industries		377,600		973,600
Popeyes Louisiana Kitchen		350,835		534,835
Rollins		0		1,175,000
Tenneco		649,825		939,825
Ulta Salon Cosmetics & Fragrance		0		359,000
Under Armour		0		319,000
Williams-Sonoma		322,873		1,242,873
Finance
Affiliated Managers Group		0		332,000
CBOE Holdings		0		963,000
Lazard		0		1,036,000
Signature Bank		0		346,000
Other Industries
EdR		1,645,545		2,349,545
Jones Lang LaSalle		371,057		820,057
Old Dominion Freight Lines		0		636,000
Energy & Minerals
Diamondback Energy		0		462,000

25

COLUMBIA ACORN® FUND

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

	Number of Shares
	12/31/15		3/31/16
Sales
Information
Amphenol		2,088,490		973,208
Bankrate		7,126,562		3,729,361
Crown Castle International		580,000		550,215
Dun & Bradstreet		199,170		0
F5 Networks		608,935		411,935
Globalstar		32,426,846		0
GTT Communications		1,627,005		1,455,841
Hackett Group		1,899,313		0
IMAX (Canada)		377,557		0
inContact		977,714		0
Infinera		1,190,676		0
IPG Photonics		718,595		392,226
Lamar Advertising		494,476		427,214
Liberty Global Series A		496,525		0
Liberty Global Series C		172,695		0
RetailMeNot		2,317,245		0
RPX		1,489,073		0
Sanmina		2,665,548		0
Towerstream		3,160,830		0
Trimble Navigation		1,025,328		0
VeriFone Holdings		764,958		0
Verint Systems		970,045		0
Verisk Analytics		725,363		483,363
Vonage		13,576,409		7,493,505
Zebra Technologies		305,828		0
Industrial Goods & Services
Allegion		413,275		0
Ametek		2,175,776		1,077,776
Donaldson		4,224,911		2,619,091
Dorman Products		644,535		0
ESCO Technologies		580,773		0
Generac		1,984,598		1,178,508
HEICO		1,752,993		1,085,754
LKQ		4,828,531		2,039,347
Moog		233,031		0
Nordson		1,231,500		409,747
Quanta Services		3,817,357		0
Thermon		885,915		0
WESCO International		532,911		0
Heath Care
Abaxis		432,548		0
Akorn		1,848,388		1,518,879
Cepheid		3,554,970		1,953,970
Envision Healthcare Holdings		989,102		0
Ultragenyx Pharmaceutical		737,622		700,940
Wright Medical Group		1,522,425		0

	Number of Shares
	12/31/15		3/31/16
Consumer Goods & Services
Avis Budget Group		1,689,192		0
Blackhawk Network		782,952		0
Casey's General Stores		168,680		0
Expedia		150,700		0
Fossil		955,020		0
Gaiam		1,893,824		0
Gentex		3,816,287		3,647,910
Hertz		3,043,059		0
Knoll		1,703,440		0
Quotient Technology		4,634,954		3,599,977
Select Comfort		1,607,263		1,255,859
The Chefs' Warehouse		481,337		0
The Fresh Market		1,858,484		0
Finance
Associated Banc-Corp		3,607,174		1,651,174
CNO Financial Group		4,070,959		2,245,695
First Busey		881,185		0
Leucadia National		2,816,479		0
MB Financial		1,333,074		923,074
McGrath Rentcorp		679,077		0
Sandy Spring Bancorp		666,576		0
Sprott (Canada)		10,694,100		0
WEX		570,235		0
Other Industries
Eversource Energy		812,774		0
Heartland Express		2,832,071		2,152,113
JB Hunt Transport Services		518,731		362,731
Post Properties		504,991		0
Rush Enterprises, Class A		1,006,783		0
Energy & Minerals
Alamos Gold (Canada)		2,200,000		0
Argonaut Gold (Canada)		3,868,000		0
Core Labs (Netherlands)		260,478		0
First Majestic (Canada)		2,148,000		0
Kaminak Gold		2,511,500		0
Kirkland Lake Gold (Canada)		5,119,843		0
ShaMaran Petroleum (Iraq)		90,046,000		0

26

COLUMBIA ACORN® FUND

STATEMENT OF INVESTMENTS (UNAUDITED), MARCH 31, 2016

Number of Shares			Value
			Equities: 98.7%
Information 28.2%
		> Business Software 7.5%
	1,138,317	Ansys (a)	$	101,833,839
		Simulation Software for Engineers & Designers
	524,073	Ultimate Software (a)		101,408,126
		Human Capital Management Systems
	3,476,086	Cadence Design Systems (a)		81,966,131
		Electronic Design Automation Software
	892,000	Manhattan Associates (a)		50,728,040
		Supply Chain Management Software & Services
	1,849,000	Cvent (a)		39,568,600
		Software for Corporate Event Planners & Marketing Platform for Hotels
	459,465	NetSuite (a)		31,468,758
		Enterprise Software Delivered via the Web
	611,961	DemandWare (a)		23,927,675
		E-Commerce Website Platform for Retailers & Apparel Manufacturers
	499,178	SPS Commerce (a)		21,434,703
		Supply Chain Management Software Delivered via the Web
	1,136,747	Textura (a)(b)		21,177,597
		Construction Vendor Management Software
				473,513,469
		> Computer Services 4.2%
	2,290,000	Booz Allen Hamilton		69,341,200
		IT Consulting for U.S. Government
	566,000	Gartner (a)		50,572,100
		IT Research & Consulting Services
	1,642,586	WNS - ADR (a)		50,328,835
		Offshore Business Process Outsourcing Services
	1,418,272	Genpact (a)		38,562,816
		Business Process Outsourcing
	629,558	ExlService Holdings (a)		32,611,104
		Business Process Outsourcing
	691,671	Virtusa (a)		25,909,996
		Offshore IT Outsourcing
				267,326,051
		> Financial Processors 2.5%
	1,567,000	Vantiv (a)		84,429,960
		Credit Card Processor
	1,261,683	CoreLogic (a)		43,780,400
		Data Processing Services for Real Estate, Insurance & Mortgages
	468,625	Global Payments		30,601,213
		Credit Card Processor
				158,811,573
		> Business Information & Marketing Services 2.5%
	319,000	Factset Research Systems		48,338,070
		Securities Data Purveyor

Number of Shares			Value
	483,363	Verisk Analytics (a)	$	38,630,371
		Risk & Decision Analytics
	2,370,162	Navigant Consulting (a)(c)		37,472,261
		Financial Consulting Firm
	3,729,361	Bankrate (a)		34,198,240
		Internet Advertising for Credit Cards, Banking/Mortgages/ Loans & Senior Living
				158,638,942
		> Instrumentation 2.3%
	170,447	Mettler-Toledo International (a)		58,763,308
		Laboratory Equipment
	1,582,634	FLIR Systems		52,147,790
		Infrared Cameras
	392,226	IPG Photonics (a)		37,685,074
		Fiber Lasers
				148,596,172
		> Internet Related 1.6%
	782,885	Verisign (a)		69,316,638
		Internet Domain Registry for .COM/.NET
	7,493,505	Vonage (a)		34,245,318
		Business & Consumer Internet Telephony
				103,561,956
		> Mobile Communications 1.6%
	550,215	Crown Castle International		47,593,597
		Communications Towers
	2,512,994	Global Eagle Entertainment (a)		21,410,709
		Provider of Entertainment & Wi-Fi on Airplanes
	185,000	SBA Communications (a)		18,531,450
		Communications Towers
	1,264,104	Gogo (a)(b)		13,917,785
		Provider of Wi-Fi on Airplanes
				101,453,541
		> Semiconductors & Related Equipment 1.3%
	795,500	MA-COM Technology Solutions Holdings (a)		34,834,945
		Radio Frequency, Microwave & Millimeterwave Semiconductors
	247,161	Littelfuse		30,427,991
		Little Fuses
	298,243	Monolithic Power Systems		18,980,184
		High Performance Analog & Mixed Signal Integrated Circuits
				84,243,120
		> Computer Hardware & Related Equipment 1.2%
	973,208	Amphenol		56,270,887
		Electronic Connectors
	356,373	Rogers (a)		21,336,051
		Printed Circuit Materials & High Performance Foams
				77,606,938

27

COLUMBIA ACORN® FUND

STATEMENT OF INVESTMENTS (UNAUDITED), CONTINUED

Number of Shares			Value
		> Telephone & Data Services 1.0%
	1,455,841	GTT Communications (a)	$	24,079,610
		Provider of High Capacity Data Transit
	2,727,319	Boingo Wireless (a)(c)		21,054,903
		Wi-Fi & Cellular Communications Networks
	626,192	Zayo Group Holdings (a)		15,178,894
		Fiber Optic Data Communications
				60,313,407
		> Telecommunications Equipment 0.9%
	411,935	F5 Networks (a)		43,603,320
		Internet Traffic Management Equipment
	829,420	CalAmp (a)		14,871,500
		Machine-to-machine Communications
				58,474,820
		> Electronics Distribution 0.8%
	1,233,000	CDW		51,169,500
		Value Added Reseller of IT Products & Services
		> Advertising 0.4%
	427,214	Lamar Advertising		26,273,661
		Outdoor Advertising
		> Cable TV 0.4%
	951,000	Starz (a)		25,039,830
		Premium CATV channel network
Information: Total				1,795,022,980
Industrial Goods & Services 20.3%
		> Machinery 7.5%
	2,619,091	Donaldson		83,575,194
		Industrial Air Filtration
	891,230	Toro		76,752,728
		Turf Maintenance Equipment
	537,743	Middleby (a)		57,414,820
		Manufacturer of Cooking Equipment
	1,077,776	Ametek		53,867,244
		Aerospace/Industrial Instruments
	1,085,754	HEICO		51,681,890
		FAA-approved Aircraft Replacement Parts
	1,178,508	Generac (a)		43,887,638
		Standby Power Generators
	1,023,931	Oshkosh Corporation		41,848,060
		Specialty Truck Manufacturer
	326,681	WABCO Holdings (a)		34,928,733
		Truck & Bus Component Supplier
	409,747	Nordson		31,157,162
		Dispensing Systems for Adhesives & Coatings
				475,113,469
		> Other Industrial Services 6.3%
	2,874,000	Expeditors International of Washington		140,279,940
		International Freight Forwarder

Number of Shares			Value
	2,172,804	Robert Half International	$	101,209,210
		Temporary & Permanent Staffing in Finance, Accounting & other Professions
	2,039,347	LKQ (a)		65,116,350
		Alternative Auto Parts Distribution
	636,000	Manpower		51,783,120
		Global Temporary Staffing Provider
	953,378	Forward Air		43,207,091
		Freight Transportation Between Airports
				401,595,711
		> Industrial Materials & Specialty Chemicals 2.7%
	872,634	Drew Industries		56,249,987
		RV & Manufactured Home Components
	734,000	Celanese		48,077,000
		Commodity & Specialty Chemicals Provider
	1,172,000	Axalta Coating Systems (a)		34,222,400
		Leading Global Manufacturer of High Performance Coatings
	260,000	International Flavors & Fragrances		29,580,200
		Flavors & Fragrances
				168,129,587
		> Construction 1.6%
	46,070	NVR (a)		79,811,668
		Homebuilder
	2,269,946	PGT (a)		22,336,269
		Wind Resistant Windows & Doors
				102,147,937
		> Electrical Components 1.1%
	329,000	Acuity Brands		71,768,060
		Commercial Lighting Fixtures
		> Waste Management 1.1%
	548,000	Stericycle (a)		69,152,120
		Medical Waste Disposal
Industrial Goods & Services: Total				1,287,906,884
Health Care 16.1%
		> Medical Supplies 4.4%
	3,255,114	VWR (a)		88,083,385
		Distributor of Lab Supplies
	1,953,970	Cepheid (a)		65,184,439
		Molecular Diagnostics
	606,405	Bio-Techne		57,317,401
		Maker of Consumables & Systems for the Life Science Market
	791,444	Dentsply Sirona		48,776,694
		Leading Dental Supplies Manufacturer
	1,806,125	Fluidigm (a)(b)(c)		14,575,429
		Life Sciences Equipment & Consumables
	70,767	West Pharmaceutical Services		4,905,568
		Components & Systems for Injectable Drug Delivery
				278,842,916

28

Number of Shares			Value
		> Medical Equipment & Devices 3.9%
	2,461,778	Align Technology (a)	$	178,946,643
		Invisalign System to Correct Malocclusion (Crooked Teeth)
	927,000	IDEXX Laboratories (a)		72,602,640
		Diagnostic Equipment & Services for Veterinarians
				251,549,283
		> Health Care Services 3.9%
	1,216,000	Quintiles Transnational Holdings (a)		79,161,600
		Contract Research Organization
	2,059,989	HealthSouth		77,517,386
		Inpatient Rehabilitation Facilities & Home Health Care
	1,197,495	Medidata Solutions (a)		46,355,031
		Cloud-based Software for Drug Studies
	661,000	Mednax (a)		42,713,820
		Physician Management for Pediatric & Anesthesia Practices
				245,747,837
		> Biotechnology & Drug Delivery 3.3%
	1,569,000	Medivation (a)		72,142,620
		Development & Marketing of Cancer Drugs
	700,940	Ultragenyx Pharmaceutical (a)		44,376,511
		Biotech Focused on "Ultra-Orphan" Drugs
	1,140,477	Seattle Genetics (a)		40,019,338
		Antibody-based Therapies for Cancer
	139,937	Intercept Pharmaceuticals (a)(b)		17,977,706
		Biotech Developing Drugs for Several Diseases
	754,526	Sarepta Therapeutics (a)		14,728,348
		Biotech Focused on Rare Diseases
	284,060	Agios Pharmaceuticals (a)(b)		11,532,836
		Biotech Focused on Cancer & Orphan Diseases
	2,640,414	Celldex Therapeutics (a)(b)		9,980,765
		Biotech Developing Drugs for Cancer
	359,944	MicroDose Therapeutx (a)(d)(e)(f)		—
		Drug Inhaler Development
				210,758,124
		> Pharmaceuticals 0.6%
	1,518,879	Akorn (a)		35,739,223
		Developer, Manufacturer & Distributor of Specialty Generic Drugs
Health Care: Total				1,022,637,383
Consumer Goods & Services 15.8%
		> Restaurants 3.1%
	919,506	Papa John's International		49,828,030
		Franchisor of Pizza Restaurants
	370,216	Domino's Pizza		48,816,682
		Franchisor of Pizza Restaurants
	1,453,484	Fiesta Restaurant Group (a)(c)		47,645,205
		Owner/Operator of Two Restaurant Chains: Pollo Tropical & Taco Cabana

Number of Shares			Value
	534,835	Popeyes Louisiana Kitchen (a)	$	27,843,510
		Popeyes Restaurants
	467,892	Dunkin Brands		22,070,466
		Franchisor of Quick Service Restaurants
				196,203,893
		> Retail 3.0%
	359,000	Ulta Salon Cosmetics & Fragrance (a)		69,552,660
		Specialty Beauty Product Retailer
	1,242,873	Williams-Sonoma		68,034,868
		Home Goods & Furnishing Retailer
	784,000	Cato		30,223,200
		Women's Apparel Retailing, Focusing on Private Labels & Low Prices
	620,000	Five Below (a)		25,630,800
		Low-price Specialty Retailer Targeting Pre-teens, Teens & Parents
				193,441,528
		> Travel 3.0%
	746,138	Vail Resorts		99,758,651
		Ski Resort Operator & Developer
	1,007,751	Choice Hotels		54,468,942
		Franchisor of Budget Hotel Brands
	1,617,678	Liberty TripAdvisor Holdings Class A (a)		35,847,744
		Holding Company for Trip Advisor
				190,075,337
		> Other Durable Goods 2.5%
	3,647,910	Gentex		57,235,708
		Manufacturer of Auto Parts
	939,825	Tenneco (a)		48,410,386
		Auto Parts for Emission Control, Suspension
	287,798	Cavco Industries (a)		26,897,601
		Manufactured Homes
	1,255,859	Select Comfort (a)		24,351,106
		Specialty Mattresses
				156,894,801
		> Leisure Products 1.5%
	973,600	Polaris Industries		95,880,128
		Leisure Vehicles & Related Products
		> Other Consumer Services 1.1%
	3,599,977	Quotient Technology (a)(b)		38,159,756
		Allows CPGs to Digitally Distribute Coupons, Advertising & Trade Promotion
	1,175,000	Rollins		31,866,040
		Pest Control & Wildlife Removal Services
				70,025,756
		> Nondurables 0.6%
	2,964,000	HRG Group (a)		41,288,520
		Holding Company

29

COLUMBIA ACORN® FUND

STATEMENT OF INVESTMENTS (UNAUDITED), CONTINUED

Number of Shares			Value
		> Consumer Electronics 0.6%
	1,003,000	iRobot (a)	$	35,405,900
		Home Robots (Vacuums, Pool Cleaners) & Battlefield Reconnaissance Robots
		> Apparel 0.4%
	319,000	Under Armour (a)		27,060,770
		Athletic Apparel, Footwear & Accessories
Consumer Goods & Services: Total				1,006,276,633
Finance 8.1%
		> Brokerage & Money Management 3.2%
	1,851,021	Eaton Vance		62,046,224
		Specialty Mutual Funds
	332,000	Affiliated Managers Group (a)		53,916,800
		Asset Manager Holding Company
	1,075,849	SEI Investments		46,315,299
		Mutual Fund Administration & Investment Management
	1,036,000	Lazard		40,196,800
		Corporate Advisory & Asset Management
				202,475,123
		> Banks 2.2%
	936,224	BOK Financial		51,136,555
		Tulsa-based Southwest Bank
	923,074	MB Financial		29,953,751
		Chicago Bank
	1,651,174	Associated Banc-Corp		29,622,062
		Midwest Bank
	264,495	SVB Financial Group (a)		26,991,715
		Bank to Venture Capitalists
				137,704,083
		> Insurance 1.0%
	2,245,695	CNO Financial Group		40,242,854
		Life, Long-term Care & Medical Supplement Insurance
	737,341	Allied World Assurance Company Holdings		25,762,695
		Commercial Lines Insurance/ Reinsurance
				66,005,549
		> Specialized Finance 1.0%
	963,000	CBOE Holdings		62,912,790
		Marketplace for Trading Options & Futures
		> Savings & Loans 0.7%
	346,000	Signature Bank (a)		47,097,520
		New York City Metro Area Bank
Finance: Total				516,195,065
Other Industries 7.9%
		> Real Estate 6.1%
	2,349,545	EdR		97,741,072
		Student Housing
	820,057	Jones Lang LaSalle		96,209,087
		Real Estate Services

Number of Shares			Value
	602,013	Extra Space Storage	$	56,264,135
		Self Storage Facilities
	145,898	Amerco		52,130,814
		North American Moving & Storage King
	328,308	Federal Realty		51,232,464
		Shopping Centers & Mixed Use Projects
	1,548,707	Terreno Realty		36,317,179
		Industrial Properties
				389,894,751
		> Transportation 1.8%
	636,000	Old Dominion Freight Lines (a)		44,278,320
		LTL Trucker
	2,152,113	Heartland Express		39,921,696
		Regional Trucker
	362,731	JB Hunt Transport Services		30,556,460
		Truck & Intermodal Carrier
				114,756,476
Other Industries: Total				504,651,227
Energy & Minerals 2.3%
		> Oil & Gas Producers 1.7%
	462,000	Diamondback Energy (a)		35,657,160
		Oil & Gas Producer in Texas
	318,103	Cimarex Energy		30,941,879
		Oil & Gas Producer in Texas, New Mexico & Oklahoma
	376,730	PDC Energy (a)		22,396,598
		Oil & Gas Producer in the United States
	668,313	Carrizo Oil & Gas (a)		20,664,238
		Oil & Gas Producer
				109,659,875
		> Oil Services 0.5%
	1,362,854	ShawCor (Canada)		29,623,383
		Oil & Gas Pipeline Products
		> Agricultural Commodities 0.1%
	1,306,818	Union Agriculture Group (Uruguay) (a)(d)(e)		4,665,340
		Farmland Operator in Uruguay
Energy & Minerals: Total				143,948,598
Total Equities: 98.7% (Cost: $4,357,811,338)				6,276,638,770	(g)
Short-Term Investments 0.5%
	27,577,253	JPMorgan U.S. Government Money Market Fund, IM Shares (7 day yield of 0.25%)		27,577,253
Total Short-Term Investments: 0.5% (Cost: $27,577,253)				27,577,253

30

Number of Shares			Value
Securities Lending Collateral 0.5%
	33,807,275	Dreyfus Government Cash Management Fund, Institutional Shares (7 day yield of 0.20%) (h)	$	33,807,275
Total Securities Lending Collateral: 0.5% (Cost: $33,807,275)				33,807,275
Total Investments: 99.7% (Cost: $4,419,195,866)(i)				6,338,023,298	(j)
Obligation to Return Collateral for Securities Loaned: (0.5)%				(33,807,275	)
Cash and Other Assets Less Liabilities: 0.8%				54,539,039
Net Assets: 100.0%			$	6,358,755,062

ADR - American Depositary Receipts

> Notes to Statement of Investments

(a)  Non-income producing security.

(b)  All or a portion of this security was on loan at March 31, 2016. The total market value of securities on loan at March 31, 2016 was $33,934,861.

(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 March 31, 2016, are as follows:

Security	Balance of Shares Held 12/31/15		Purchases/ Additions		Sales/ Reductions		Balance of Shares Held 3/31/16		Value		Dividend
Fiesta Restaurant Group		1,453,484		-		-		1,453,484	$	47,645,205	$	-
Quotient Technology Inc. (1)		4,634,954		-		1,034,977		3,599,977		38,159,756		-
Navigant Consulting		2,370,162		-		-		2,370,162		37,472,261		-
Vonage (1)		13,576,409		-		6,082,904		7,493,505		34,245,318		-
Bankrate (1)		7,126,562		-		3,397,201		3,729,361		34,198,240		-
Boingo Wireless		2,727,319		-		-		2,727,319		21,054,903		-
Fluidigm		879,013		927,112		-		1,806,125		14,575,429		-
Gaiam (1)		1,893,824		-		1,893,824		-		-		-
Hackett Group (1)		1,899,313		-		1,899,313		-		-		-
Kirkland Lake Gold (1)		5,119,843		-		5,119,843		-		-		-
ShaMaran Petroleum (1)		90,046,000		-		90,046,000		-		-		-
Total of Affiliated Transactions		131,726,883		927,112		109,474,062		23,179,933	$	227,351,112	$	-

(1)  At March 31, 2016, the Fund owned less than five percent of the company's outstanding voting shares.

  The aggregate cost and value of these companies at March 31, 2016, was $113,103,333 and $120,747,798, respectively. Investments in affiliated companies represented 1.90% of the Fund's total net assets at March 31, 2016.

(d)  Illiquid security.

(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 March 31, 2016, the market value of these securities amounted to $4,665,340, which represented 0.07% of total net assets. Additional information on these securities is as follows:

Security	Acquisition Dates	Shares		Cost		Value
Union Agriculture Group	12/8/10-6/27/12		1,306,818	$	15,000,000	$	4,665,340
MicroDose Therapeutx Contingent Value Rights	8/14/13		359,944		-		-
				$	15,000,000	$	4,665,340

31

COLUMBIA ACORN® FUND

STATEMENT OF INVESTMENTS (UNAUDITED), CONTINUED

> Notes to Statement of Investments

(f)  Security has no value.

(g)  On March 31, 2016, the market value of foreign securities represented 0.54% of total net assets. The Fund's foreign portfolio was diversified as follows:

Country	Value		Percentage of Net Assets
Canada	$	29,623,383		0.47
Uruguay		4,665,340		0.07
Total Foreign Portfolio	$	34,288,723		0.54

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

(i)  At March 31, 2016, for federal income tax purposes, the cost of investments was approximately $4,419,195,866 and net unrealized appreciation was $1,918,827,432 consisting of gross unrealized appreciation of $2,114,989,738 and gross unrealized depreciation of $196,162,306.

(j)  Securities are valued using policies described in the Notes to Financial Statements in the shareholder report dated December 31, 2015.

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.

32

> Notes to Statement of Investments

  The following table summarizes the inputs used, as of March 31, 2016, 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	$	1,795,022,980	$	-	$	-		$	1,795,022,980
Industrial Goods & Services		1,287,906,884		-		-			1,287,906,884
Health Care		1,022,637,383		-		0	(a)		1,022,637,383
Consumer Goods & Services		1,006,276,633		-		-			1,006,276,633
Finance		516,195,065		-		-			516,195,065
Other Industries		504,651,227		-		-			504,651,227
Energy & Minerals		139,283,258		-		4,665,340			143,948,598
Total Equities		6,271,973,430		-		4,665,340			6,276,638,770
Total Short-Term Investments		27,577,253		-		-			27,577,253
Total Securities Lending Collateral		33,807,275		-		-			33,807,275
Total Investments	$	6,333,357,958	$	-	$	4,665,340		$	6,338,023,298

(a)  Rounds to zero.

  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. Significant increases or decreases to any of these inputs could result in a significantly lower or higher fair value measurement.

33

COLUMBIA ACORN INTERNATIONAL®

MAJOR PORTFOLIO CHANGES IN THE FIRST QUARTER (UNAUDITED)

	Number of Shares
	12/31/15		3/31/16
Purchases
Europe
> United Kingdom
easyJet		0		1,377,000
Halfords		6,222,700		6,314,852
Next		296,000		657,000
Ocado		5,908,000		8,388,000
Rightmove		1,480,181		1,746,181
Shaftesbury		2,100,000		4,723,313
> Germany
Fielmann		0		610,000
Wirecard		2,145,000		2,380,000
Zalando		994,520		1,660,000
> Sweden
Millicom International Cellular		590,000		850,000
Trelleborg		1,317,000		4,744,000
> Switzerland
Actelion		0		310,000
Givaudan		0		29,100
> Denmark
Novozymes		1,647,800		2,908,544
> Spain
Prosegur		9,976,000		10,692,000
> France
Elior Group		0		2,023,000
Legrand		621,000		906,000
> Netherlands
ASM International		0		606,900
Brunel		858,156		870,217
Gemalto		650,000		756,000
> Italy
Brembo		0		48,500
Asia
> Japan
Aeon Financial Service		1,260,000		1,776,000
Aeon Mall		3,355,000		4,080,000
Aica Kogyo		1,237,000		1,437,000
Bandai Namco		1,517,000		2,355,700
Disco		361,400		385,400
Dowa Holdings		3,400,000		5,000,000
Hikari Tsushin		281,900		551,700
Hoshizaki Electric		320,000		450,000
Japan Airport Terminal		450,000		750,000
Makita		0		550,000
MonotaRO		0		869,000
NGK Spark Plug		1,190,000		1,550,000
OSG		1,230,000		1,800,000
Otsuka		532,000		742,000
Recruit Holdings		1,702,000		2,132,400

	Number of Shares
	12/31/15		3/31/16
Sega Sammy Holdings		2,083,000		2,900,000
Seria		0		59,000
Seven Bank		6,500,000		10,700,000
Sony Financial Holdings		2,400,000		2,523,800
Suruga Bank		2,100,000		2,900,000
> Taiwan
Advantech		3,843,686		4,243,686
Largan Precision		369,000		437,000
Vanguard International Semiconductor		22,456,000		25,313,000
> Korea
CJ Corp		200,271		256,310
Korea Investment Holdings		858,602		989,002
KT&G		478,317		622,317
> China
China Everbright International		33,500,000		64,000,000
Sihuan Pharmaceutical Holdings Group		90,360,000		173,400,001
> Hong Kong
Samsonite International		12,000,000		18,000,000
Value Partners		60,000,000		67,979,000
> India
Adani Ports & Special Economic Zone		6,095,000		9,413,000
TVS Motor		0		3,050,431
> Thailand
Airports of Thailand		4,360,000		5,000,000
> Indonesia
Matahari Department Store		15,103,600		22,193,600
Tower Bersama Infrastructure		27,920,000		43,966,800
Other Countries
> Canada
Boardwalk Real Estate Investment Trust		0		199,274
CCL Industries		633,741		712,923
PrairieSky Royalty		1,875,000		2,208,000
Vermilion Energy		1,449,000		1,651,000
> Australia
Amcor		3,692,000		5,950,000
IAG		12,604,154		16,600,000
> United States
Cepheid		0		1,064,000
Latin America
> Mexico
Grupo Aeroportuario del Sureste - ADR		300,000		396,000
> Guatemala
Tahoe Resources		2,320,000		3,242,476

34

	Number of Shares
	12/31/15		3/31/16
Sales
Europe
> United Kingdom
Assura		41,580,000		0
Babcock International		2,392,000		0
Cable and Wireless		22,365,095		0
Connect Group		10,425,001		0
Elementis		5,650,001		0
Fidessa Group		165,813		0
Polypipe		6,037,800		1,416,057
PureCircle		3,075,000		1,078,904
WH Smith		2,638,000		2,097,000
> Germany
Deutsche Boerse		575,000		0
Rational		75,000		60,300
> Sweden
Modern Times Group		1,072,742		0
Sweco		3,290,652		2,117,652
Swedish Match		967,247		0
> Switzerland
Inficon		48,450		0
Panalpina Welttransport Holding		190,000		0
> Denmark
SimCorp		1,932,063		1,300,063
> Spain
Distribuidora Internacional de Alimentación		16,973,000		11,975,000
> Netherlands
Arcadis		1,573,025		0
Core Labs		255,510		0
Vopak		718,124		0
> Finland
Sponda		5,462,710		0
Tikkurila		1,033,175		842,036
> Italy
Hera		8,951,000		8,693,952
Industria Macchine Automatiche		459,000		0
> Norway
Atea		2,612,959		979,106
Orkla		3,934,736		0
> Kazakhstan
Halyk Savings Bank of Kazakhstan - GDR		2,130,426		233,780

	Number of Shares
	12/31/15		3/31/16
Asia
> Japan
Aozora Bank		9,840,000		0
Ariake Japan		833,800		557,000
Asahi Intecc		780,000		724,000
Capcom		1,226,050		972,050
Doshisha		1,340,300		777,500
Ebara		7,130,000		0
FamilyMart		1,447,000		1,247,800
Icom		426,900		119,200
IHI		15,800,000		0
JIN		930,000		803,100
Kansai Paint		2,340,900		0
Kintetsu World Express		1,548,800		1,055,000
NGK Insulators		1,400,000		0
Nippon Shokubai		405,400		0
Park24		1,463,000		0
Relia		2,210,300		1,829,800
Santen Pharmaceutical		2,451,000		2,283,000
Tamron		837,200		0
Toto		775,000		0
Yamaguchi Financial Group		1,164,000		0
> Taiwan
Delta Electronics		7,251,036		0
Far EasTone Telecom		23,150,000		22,000,000
Novatek Microelectronics		2,126,000		1,060,000
> Korea
LF Corp		619,802		37,477
> China
AMVIG Holdings		33,609,500		0
CAR Inc		26,542,000		0
Jiangnan Group		85,498,000		0
NewOcean Energy		46,044,000		32,500,000
Phoenix Healthcare Group		2,643,000		0
TravelSky Technology		21,449,000		20,348,000
> Hong Kong
Mapletree Greater China Commercial Trust		50,903,000		0
Vitasoy International		15,000,000		0
> India
Amara Raja		363,454		0
Colgate Palmolive India		1,809,000		0
Container Corporation of India		1,505,000		0
United Breweries		1,850,000		1,506,698
Zee Entertainment Enterprises		13,478,000		10,092,584
> Singapore
China Everbright Water		3,989,300		0
Petra Foods		8,192,300		0
Singapore Exchange		11,000,000		8,124,700

35

COLUMBIA ACORN INTERNATIONAL®

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

	Number of Shares
	12/31/15		3/31/16
Sales (continued)
Asia—continued
> Indonesia
Link Net		33,000,000		3,708,300
> Philippines
Melco Crown (Philippines) Resorts		90,000,000		0
Puregold Price Club		30,000,000		12,000,000
Robinsons Retail Holdings		9,700,000		0
> Cambodia
Nagacorp		27,493,900		0
Other Countries
> Canada
Ag Growth		556,758		0
Keyera		1,192,000		0
Onex Capital		490,200		0
Rona		2,115,898		0
ShawCor		1,067,730		0
> Australia
Challenger Financial		2,800,000		0
Domino's Pizza Enterprises		2,200,000		1,648,566
> United States
Bladex		1,307,000		0
> New Zealand
Auckland International Airport		10,000,000		7,219,755
Latin America
> Brazil
Localiza Rent a Car		3,500,000		0

36

COLUMBIA ACORN INTERNATIONAL®

STATEMENT OF INVESTMENTS (UNAUDITED), MARCH 31, 2016

Number of Shares			Value
			Equities: 95.3%
Europe 44.8%
		> United Kingdom 13.3%
	1,746,181	Rightmove	$	105,609,820
		Internet Real Estate Listings
	1,253,571	Spirax Sarco		65,536,029
		Steam Systems for Manufacturing & Process Industries
	13,812,000	Regus		62,825,280
		Rental of Office Space in Full Service Business Center
	4,723,313	Shaftesbury		61,800,915
		London Prime Retail REIT
	4,399,000	Halma		57,589,119
		Health & Safety Sensor Technology
	2,097,000	WH Smith		54,754,789
		Newsprint, Books & General Stationery Retailer
	3,560,000	Domino's Pizza UK & Ireland		51,539,516
		Pizza Delivery in the UK, Ireland & Switzerland
	657,000	Next		50,955,249
		Clothes & Home Retailer in the UK
	3,000,000	Smith & Nephew		49,464,423
		Medical Equipment & Supplies
	1,125,000	Croda International		49,103,565
		Oleochemicals & Industrial Chemicals
	16,251,000	Rentokil Initial		41,265,979
		Pest Control, Washroom & Workwear Service Provider
	6,314,852	Halfords		35,925,086
		UK Retailer of Leisure Goods & Auto Parts
	5,965,000	DS Smith		34,954,284
		Packaging
	8,388,000	Ocado (a)(b)		34,949,097
		Online Grocery Retailer
	4,033,732	Abcam		34,181,322
		Online Sales of Antibodies
	1,377,000	easyJet		30,041,493
		European Low Cost Airline
	1,416,057	Polypipe		6,491,924
		Manufacturer of Plastic Piping & Fittings
	1,078,904	PureCircle (a)(b)		5,876,763
		Natural Sweeteners
				832,864,653
		> Germany 6.4%
	2,380,000	Wirecard (b)		90,183,111
		Online Payment Processing & Risk Management
	691,000	MTU Aero Engines		66,276,280
		Airplane Engine Components & Services
	1,067,000	NORMA Group		59,772,067
		Clamps for Automotive & Industrial Applications
	1,660,000	Zalando (a)		54,495,160
		Online Platform for Apparel Sales

Number of Shares			Value
	8,700,000	Telefonica Deutschland	$	47,132,606
		Mobile & Fixed-line Communications in Germany
	610,000	Fielmann		46,297,729
		Retail Optician Chain
	60,300	Rational		32,228,634
		Commercial Ovens
				396,385,587
		> Sweden 6.1%
	4,744,000	Trelleborg		93,848,600
		Manufacturer of Sealing, Dampening & Protective Solutions for Industry
	7,587,376	Unibet		86,124,066
		European Online Gaming Operator
	2,055,208	Hexagon		79,998,242
		Design, Measurement & Visualization Software & Equipment
	850,000	Millicom International Cellular		46,456,441
		Telecoms Operator in Latin America & Africa
	2,117,652	Sweco		34,797,496
		Engineering Consultants
	916,000	Mekonomen		22,679,272
		Nordic Integrated Wholesaler/ Retailer of Automotive Parts & Service
	849,000	Recipharm (b)		15,896,037
		Contract Development Manufacturing Organization
				379,800,154
		> Switzerland 4.6%
	249,500	Partners Group		100,287,817
		Private Markets Asset Management
	228,300	Geberit		85,308,294
		Plumbing Systems
	29,100	Givaudan		57,077,219
		Fragrances & Flavors
	310,000	Actelion		46,328,324
		Swiss Orphan Drug Company
				289,001,654
		> Denmark 4.2%
	2,908,544	Novozymes		130,759,006
		Industrial Enzymes
	700,000	William Demant Holding (a)		70,390,166
		Manufacture & Distribution of Hearing Aids & Diagnostic Equipment
	1,300,063	SimCorp		59,995,272
		Software for Investment Managers
				261,144,444
		> Spain 3.1%
	11,975,000	Distribuidora Internacional de Alimentación		62,217,915
		Discount Retailer in Spain & Latin America
	10,692,000	Prosegur		60,223,802
		Security Guards
	627,000	Viscofan		37,563,836
		Sausage Casings Maker
	975,553	Bolsas y Mercados Españoles		31,470,812
		Spanish Stock Markets
				191,476,365

37

COLUMBIA ACORN INTERNATIONAL®

STATEMENT OF INVESTMENTS (UNAUDITED), CONTINUED

Number of Shares			Value
		> France 2.9%
	906,000	Legrand	$	50,768,504
		Electrical Components
	1,496,610	Eutelsat		48,347,949
		Fixed Satellite Services
	2,023,000	Elior Group		44,358,987
		Contract Caterer & Travel Concessionary
	99,000	Eurofins Scientific		36,313,398
		Food, Pharmaceuticals & Materials Screening & Testing
				179,788,838
		> Netherlands 2.8%
	2,103,770	Aalberts Industries		72,989,385
		Flow Control & Heat Treatment
	756,000	Gemalto (b)		55,890,589
		Digital Security Solutions
	606,900	ASM International		27,185,130
		Semiconductor Manufacturing Equipment Provider
	870,217	Brunel (b)		18,324,016
		Temporary Specialist & Energy Staffing
				174,389,120
		> Finland 0.8%
	1,387,000	Konecranes (b)		33,112,042
		Manufacture & Service of Industrial Cranes & Port Handling Equipment
	842,036	Tikkurila		15,292,116
		Decorative & Industrial Paint in Scandinavia, Central & Eastern Europe
				48,404,158
		> Italy 0.5%
	8,693,952	Hera		25,978,614
		Northern Italian Utility
	48,500	Brembo		2,508,301
		Original Equipment, Racing & Aftermarket Brakes for the Automotive Industry
				28,486,915
		> Norway 0.1%
	979,106	Atea		9,347,695
		Nordic IT Hardware/Software Reseller & Integrator
		> Kazakhstan —%
	233,780	Halyk Savings Bank of Kazakhstan - GDR		981,876
		Retail Bank & Insurer in Kazakhstan
Europe: Total				2,792,071,459
Asia 37.6%
		> Japan 21.4%
	2,132,400	Recruit Holdings		65,018,313
		Recruitment & Media Services
	1,247,800	FamilyMart		64,805,070
		Convenience Store Operator

Number of Shares			Value
	4,080,000	Aeon Mall	$	60,364,362
		Suburban Shopping Mall Developer, Owner & Operator
	1,640,000	Glory		55,701,927
		Currency Handling Systems & Related Equipment
	2,355,700	Bandai Namco		51,350,525
		Branded Toys & Related Content
	2,900,000	Suruga Bank		50,890,672
		Regional Bank
	964,900	Ezaki Glico		49,424,834
		Confectionary, Ice Cream & Dairy Products
	3,600,000	Ushio		47,791,119
		Industrial Light Sources
	10,700,000	Seven Bank		45,668,393
		ATM Processing Services
	18,600	Japan Retail Fund		44,657,732
		Retail REIT in Japan
	551,700	Hikari Tsushin		41,984,156
		Office IT/Mobiles/Insurance Distribution
	1,776,000	Aeon Financial Service		41,811,122
		Diversified Consumer-related Finance Company in Japan
	742,000	Otsuka		39,141,399
		One-stop IT Services & Office Supplies Provider
	450,000	Hoshizaki Electric		37,534,830
		Commercial Kitchen Equipment
	6,149	Kenedix Office Investment		35,249,167
		Tokyo Mid-size Office REIT
	2,283,000	Santen Pharmaceutical		34,314,585
		Specialty Pharma (Ophthalmic Medicine)
	550,000	Makita		34,091,678
		Power Tools
	724,000	Asahi Intecc		33,876,442
		Medical Guidewires for Surgery
	1,800,000	OSG (b)		33,570,983
		Consumable Cutting Tools
	298,620	Hirose Electric		32,910,659
		Electrical Connectors
	557,000	Ariake Japan		32,635,657
		Commercial Soup & Sauce Extracts
	385,400	Disco		32,609,055
		Semiconductor Dicing & Grinding Equipment
	2,523,800	Sony Financial Holdings		32,270,849
		Life Insurance, Assurance & Internet Banking
	4,554,000	NOF		32,256,106
		Specialty Chemicals, Life Science & Rocket Fuels
	2,900,000	Sega Sammy Holdings		31,596,035
		Gaming Software/Hardware & Leisure Facilities
	803,100	JIN (b)		31,360,607
		Eyeglasses Retailer
	1,437,000	Aica Kogyo		30,147,349
		Laminated Sheets, Building Materials & Chemical Adhesives

38

Number of Shares			Value
		> Japan—continued
	567,000	OBIC	$	29,973,737
		Computer Software
	1,550,000	NGK Spark Plug		29,681,332
		Automobile Parts
	5,000,000	Dowa Holdings		27,817,092
		Environmental/Recycling, Nonferrous Metals, Electric Material & Metal Processing
	750,000	Japan Airport Terminal (b)		26,618,518
		Airport Terminal Operator at Haneda
	869,000	MonotaRO (b)		25,831,523
		Online Maintenance, Repair & Operations Goods Distributor in Japan
	972,050	Capcom		23,681,864
		Packaged, Online & Mobile Games
	1,829,800	Relia		16,924,384
		Call Center Operator
	777,500	Doshisha		14,306,039
		Consumer Goods Wholesaler
	1,055,000	Kintetsu World Express		14,012,536
		Airfreight Logistics
	59,000	Seria		3,563,594
		100 Yen Discount Stores
	119,200	Icom		2,178,142
		Two Way Radio Communication Equipment
				1,337,622,387
		> Taiwan 3.1%
	22,000,000	Far EasTone Telecom		49,272,821
		Mobile Operator in Taiwan
	25,313,000	Vanguard International Semiconductor		39,546,226
		Semiconductor Foundry
	1,780,000	St. Shine Optical		36,294,139
		Disposable Contact Lens Original Equipment Manufacturer
	437,000	Largan Precision		33,871,487
		Mobile Device Camera Lenses & Modules
	4,243,686	Advantech		31,184,841
		Industrial PC & Components
	1,060,000	Novatek Microelectronics		4,266,966
		Display-related Integrated Circuit Designer
				194,436,480
		> Korea 3.1%
	622,317	KT&G		59,922,925
		Tobacco & Ginseng Products
	135,947	KCC		49,428,218
		Paint & Housing Material Manufacturer
	256,310	CJ Corp		43,823,713
		Holding Company of Korean Consumer Conglomerate
	989,002	Korea Investment Holdings		38,042,723
		Brokerage & Asset Management
	37,477	LF Corp		848,737
		Apparel Design & Retail
				192,066,316

Number of Shares			Value
		> China 2.8%
	64,000,000	China Everbright International	$	71,470,733
		Municipal Waste Operator
	173,400,001	Sihuan Pharmaceutical Holdings Group		49,623,647
		Chinese Generic Drug Manufacturer
	20,348,000	TravelSky Technology		33,359,236
		Chinese Air Travel Transaction Processor
	32,500,000	NewOcean Energy		11,696,716
		Southern China Liquefied Petroleum Gas Distributor
	258,000	51job - ADR (a)		8,003,160
		Integrated Human Resource Services
				174,153,492
		> Hong Kong 2.1%
	67,979,000	Value Partners (b)		71,381,504
		Mutual Fund Management
	18,000,000	Samsonite International		60,292,065
		Mass Market Luggage & Travel Accessories
				131,673,569
		> India 2.0%
	10,092,584	Zee Entertainment Enterprises		58,955,484
		Indian Programmer of Pay Television Content
	9,413,000	Adani Ports & Special Economic Zone		35,194,404
		Indian Ports
	1,506,698	United Breweries		18,818,829
		Indian Brewer
	3,050,431	TVS Motor		14,870,579
		Indian Maker of Scooters, Mopeds, Motorcycles & Three-wheelers
				127,839,296
		> Singapore 1.1%
	8,124,700	Singapore Exchange		47,876,488
		Singapore Equity & Derivatives Market Operator
	35,000,000	SIIC Environment (a)		17,771,228
		Waste Water Treatment Operator
				65,647,716
		> Thailand 0.9%
	5,000,000	Airports of Thailand		57,082,234
		Airport Operator of Thailand
		> Indonesia 0.9%
	22,193,600	Matahari Department Store		30,710,740
		Department Store Chain in Indonesia
	43,966,800	Tower Bersama Infrastructure (a)		19,276,749
		Communications Towers
	54,624,000	MNC Sky Vision (a)		4,572,597
		Satellite Pay TV Operator in Indonesia
	3,708,300	Link Net (a)		1,147,678
		Fixed Broadband & CATV Service Provider
				55,707,764

39

COLUMBIA ACORN INTERNATIONAL®

STATEMENT OF INVESTMENTS (UNAUDITED), CONTINUED

Number of Shares			Value
		> Philippines 0.2%
	12,000,000	Puregold Price Club	$	9,486,372
		Supermarket Operator in the Philippines
Asia: Total				2,345,715,626
Other Countries 11.4%
		> Canada 4.3%
	712,923	CCL Industries		135,311,276
		Global Label Converter
	1,651,000	Vermilion Energy (b)		48,319,161
		Canadian Exploration & Production Company
	2,208,000	PrairieSky Royalty (b)		41,890,371
		Canadian Owner of Oil & Gas Mineral Interests
	3,188,000	CAE		36,869,113
		Flight Simulator Equipment & Training Centers
	199,274	Boardwalk Real Estate Investment Trust		7,946,410
		Canadian Residential REIT
				270,336,331
		> Australia 4.3%
	1,648,566	Domino's Pizza Enterprises		72,562,485
		Domino's Pizza Operator in Australia & New Zealand
	16,600,000	IAG		70,896,946
		General Insurance Provider
	5,950,000	Amcor		65,337,353
		Global Leader in Flexible & Rigid Packaging
	63,000,000	Spotless (c)		61,003,292
		Facility Management & Catering Company
				269,800,076
		> South Africa 1.2%
	8,520,458	Coronation Fund Managers (b)		42,360,621
		South African Fund Manager
	11,177,427	Rand Merchant Insurance		31,509,915
		Directly Sold Property & Casualty Insurance; Holdings in other Insurers
				73,870,536
		> United States 0.6%
	1,064,000	Cepheid (a)		35,495,040
		Molecular Diagnostics
		> Egypt 0.5%
	7,454,462	Commercial International Bank of Egypt		32,218,904
		Leading Private Universal Bank in Egypt
		> New Zealand 0.5%
	7,219,755	Auckland International Airport		32,080,130
		Auckland Airport Operator
Other Countries: Total				713,801,017

Number of Shares			Value
Latin America 1.5%
		> Mexico 0.9%
	396,000	Grupo Aeroportuario del Sureste - ADR	$	59,467,320
		Mexican Airport Operator
		> Guatemala 0.5%
	3,242,476	Tahoe Resources		32,505,900
		Silver & Gold Projects in Guatemala, Canada & Peru
		> Uruguay 0.1%
	1,306,818	Union Agriculture Group (a)(d)(e)		4,665,340
		Farmland Operator in Uruguay
Latin America: Total				96,638,560
Total Equities: 95.3% (Cost: $4,885,450,380)				5,948,226,662	(f)
Short-Term Investments 4.1%
	220,000,000	JPMorgan U.S. Government Money Market Fund, IM Shares (7 day yield of 0.25%)		220,000,000
	36,946,692	JPMorgan U.S. Government Money Market Fund, Agency Shares (7 day yield of 0.15%)		36,946,692
Total Short-Term Investments: 4.1% (Cost: $256,946,692)				256,946,692
Securities Lending Collateral 3.8%
	235,842,666	Dreyfus Government Cash Management Fund, Institutional Shares (7 day yield of 0.20%) (g)		235,842,666
Total Securities Lending Collateral: 3.8% (Cost: $235,842,666)				235,842,666
Total Investments: 103.2% (Cost: $5,378,239,738)(h)				6,441,016,020	(i)
Obligation to Return Collateral for Securities Loaned: (3.8)%				(235,842,666	)
Cash and Other Assets Less Liabilities: 0.6%				33,741,636
Net Assets: 100.0%			$	6,238,914,990

ADR - American Depositary Receipts

GDR - Global Depositary Receipts

REIT - Real Estate Investment Trust

40

> Notes to Statement of Investments

(a)  Non-income producing security.

(b)  All or a portion of this security was on loan at March 31, 2016. The total market value of securities on loan at March 31, 2016 was $225,508,166.

(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 March 31, 2016, are as follows:

Security	Balance of Shares Held 12/31/15		Purchases/ Additions		Sales/ Reductions		Balance of Shares Held 3/31/16		Value		Dividend
Spotless		63,000,000		-		-		63,000,000	$	61,003,292	$	1,686,164

  The aggregate cost and value of these companies at March 31, 2016, was $97,959,201 and $61,003,292, respectively. Investments in affiliated companies represented 0.98% of the Fund's total net assets at March 31, 2016.

(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 March 31, 2016, the market value of this security amounted to $4,665,340, which represented 0.07% of total net assets. Additional information on this security is as follows:

Security	Acquisition Dates	Shares		Cost		Value
Union Agriculture Group	12/8/10-6/27/12		1,306,818	$	15,000,000	$	4,665,340

(f)  On March 31, 2016, the Fund's total equity investments were denominated in currencies as follows:

Currency	Value		Percentage of Net Assets
Japanese Yen	$	1,337,622,387		21.4
Euro		1,018,930,982		16.3
British Pound		832,864,653		13.4
Swedish Krona		379,800,154		6.1
Other currencies less than 5% of total net assets		2,379,008,486		38.1
Total Equities	$	5,948,226,662		95.3

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

(h)  At March 31, 2016, for federal income tax purposes, the cost of investments was approximately $5,378,239,738 and net unrealized appreciation was $1,062,776,282 consisting of gross unrealized appreciation of $1,364,195,438 and gross unrealized depreciation of $301,419,156.

(i)  Securities are valued using policies described in the Notes to Financial Statements in the shareholder report dated December 31, 2015.

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

41

COLUMBIA ACORN INTERNATIONAL®

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.

  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.

  The following table summarizes the inputs used, as of March 31, 2016, 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	$	-	$	2,792,071,459	$	-	$	2,792,071,459
Asia		8,003,160		2,337,712,466		-		2,345,715,626
Other Countries		305,831,371		407,969,646		-		713,801,017
Latin America		91,973,220		-		4,665,340		96,638,560
Total Equities		405,807,751		5,537,753,571		4,665,340		5,948,226,662
Total Short-Term Investments		256,946,692		-		-		256,946,692
Total Securities Lending Collateral		235,842,666		-		-		235,842,666
Total Investments	$	898,597,109	$	5,537,753,571	$	4,665,340	$	6,441,016,020

  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 3 to Level 2 as trading resumed 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 3 and Level 2 of the fair value hierarchy:

Transfers In				Transfers Out
Level 2		Level 3		Level 2		Level 3
$	34,937,684	$	-	$	-	$	34,937,684

  Transfers into 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.

42

COLUMBIA ACORN INTERNATIONAL®

PORTFOLIO DIVERSIFICATION (UNAUDITED)

At March 31, 2016, the Fund's portfolio investments as a percentage of net assets were diversified as follows:

	Value		Percentage of Net Assets
> Industrial Goods & Services
Industrial Materials & Specialty Chemicals	$	523,249,533		8.4
Machinery		351,548,189		5.6
Outsourcing Services		243,642,369		3.9
Other Industrial Services		223,463,227		3.6
Electrical Components		131,470,281		2.1
Conglomerates		116,813,098		1.9
Construction		91,800,218		1.5
Waste Management		71,470,733		1.1
Industrial Distribution		25,831,523		0.4
Water		17,771,228		0.3
		1,797,060,399		28.8
> Consumer Goods & Services
Retail		401,407,791		6.4
Nondurables		195,234,200		3.1
Restaurants		168,460,988		2.7
Food & Beverage		144,319,919		2.3
Casinos & Gaming		117,720,101		1.9
Leisure Products		111,642,591		1.8
Consumer Goods Distribution		102,587,925		1.7
Other Durable Goods		47,060,213		0.8
Apparel		848,737		0.0	*
		1,289,282,465		20.7
> Information
Business Software		203,326,489		3.3
Internet Related		168,108,139		2.7
Financial Processors		138,059,599		2.2
Semiconductors & Related Equipment		103,607,377		1.7
Telephone & Data Services		93,589,047		1.5
Computer Hardware & Related Equipment		87,075,429		1.4
Mobile Communications		70,727,712		1.1
Advertising		65,018,313		1.0
Entertainment Programming		58,955,484		0.9
Instrumentation		57,589,119		0.9
Satellite Broadcasting & Services		52,920,546		0.9
Computer Services		48,489,094		0.8
Telecommunications Equipment		33,871,487		0.5
Consumer Software		23,681,864		0.4
Business Information & Marketing Services		16,924,384		0.3
Cable TV		1,147,678		0.0	*
		1,223,091,761		19.6

	Value			Percentage of Net Assets
> Finance
Brokerage & Money Management	$	214,029,941			3.4
Banks		171,570,967			2.7
Insurance		134,677,711			2.2
Diversified Financial Companies		99,843,638			1.6
Financial Processors		31,470,812			0.5
		651,593,069			10.4
> Other Industries
Transportation		240,243,980			3.8
Real Estate		148,217,671			2.4
Regulated Utilities		25,978,614			0.4
		414,440,265			6.6
> Health Care
Medical Equipment & Devices		153,731,030			2.5
Pharmaceuticals		146,162,592			2.3
Medical Supplies		105,970,501			1.7
		405,864,123			6.5
> Energy & Minerals
Oil & Gas Producers		90,209,532			1.5
Mining		32,505,900			0.5
Non-Ferrous Metals		27,817,092			0.4
Oil Refining, Marketing & Distribution		11,696,716			0.2
Agricultural Commodities		4,665,340			0.1
		166,894,580			2.7
Total Equities:		5,948,226,662			95.3
Short-Term Investments:		256,946,692			4.1
Securities Lending Collateral:		235,842,666			3.8
Total Investments:		6,441,016,020			103.2
Obligation to Return Collateral for Securities Loaned:		(235,842,666	)		(3.8	)
Cash and Other Assets Less Liabilities:		33,741,636			0.6
Net Assets:	$	6,238,914,990			100.0

*  Rounds to zero.

43

COLUMBIA ACORN USA®

MAJOR PORTFOLIO CHANGES IN THE FIRST QUARTER (UNAUDITED)

	Number of Shares
	12/31/15		3/31/16
Purchases
Information
CalAmp		151,561		251,287
Corporate Executive Board		0		105,287
Guidewire		0		138,645
J2 Global Communications		0		114,691
Lumos Networks		755,747		788,516
Manhattan Associates		0		125,555
NIC		0		330,297
Q2 Holdings		0		134,390
Tyler Technologies		0		41,000
WNS - ADR		237,083		308,890
Health Care
Abiomed		0		63,000
AMN Healthcare Services		0		304,182
Cambrex		0		133,313
Healthcare Services Group		0		141,000
HealthSouth		78,063		294,451
Ligand Pharmaceuticals		0		73,260
Medidata Solutions		229,409		244,664
Repligen		0		278,000
TeamHealth		0		69,429
VWR		339,261		426,782
West Pharmaceutical Services		0		109,000
ZELTIQ Aesthetics		0		330,724
Industrial Goods & Services
CoStar Group		0		46,858
ESCO Technologies		222,003		254,107
Korn/Ferry International		0		154,643
Maximus		0		123,714
Middleby		58,648		72,355
ServiceMaster		0		168,202
Consumer Goods & Services
Brunswick Corp		0		194,023
Choice Hotels		74,609		162,663
Five Below		45,980		103,839
iRobot		63,000		104,190
Liberty TripAdvisor Holdings Class A		165,011		175,984
Pool		38,918		60,506
Texas Roadhouse		0		162,108
Unifirst		0		91,054
Zoës Kitchen		0		135,576

	Number of Shares
	12/31/15		3/31/16
Finance
MarketAxess		0		81,054
Sandy Spring Bancorp		88,535		149,411
Virtu Financial		0		294,354
Other Industries
Colliers International Group		0		271,911
Energy & Minerals
Carrizo Oil & Gas		144,642		195,854

44

	Number of Shares
	12/31/15		3/31/16
Sales
Information
Amber Road		816,768		0
Ansys		240,661		115,623
Bankrate		752,841		0
Boingo Wireless		649,788		0
CoreLogic		248,783		156,327
Cvent		268,555		240,554
DemandWare		206,508		181,241
ExlService Holdings		347,076		202,933
Global Eagle Entertainment		185,000		0
Global Payments		117,190		97,431
Globalstar		1,446,597		0
Gogo		337,098		0
GTT Communications		100,616		0
Hackett Group		227,671		0
inContact		139,625		0
Infinera		311,356		0
IPG Photonics		181,962		90,760
Knowles		164,817		0
MA-COM Technology Solutions Holdings		70,533		0
Monolithic Power Systems		144,642		115,412
NetSuite		102,597		73,420
RetailMeNot		261,135		0
Rubicon Technology		1,354,071		588,690
Sanmina		367,066		0
SPS Commerce		213,071		127,531
Textura		504,838		0
Virtusa		242,233		133,947
Vonage		864,374		0
Heath Care
Abaxis		42,258		0
Akorn		297,079		186,441
Celldex Therapeutics		403,593		0
Cepheid		511,179		0
Envision Healthcare Holdings		161,988		0
Fluidigm		337,000		0
Sirona Dental Systems		40,980		0
Ultragenyx Pharmaceutical		99,654		61,654
Wright Medical Group		426,221		0
Industrial Goods & Services
Ametek		442,571		99,071
Donaldson		500,888		212,114
Dorman Products		190,519		134,361
Drew Industries		374,402		248,550
Generac		267,401		89,922
HEICO		570,840		177,840
Moog		148,971		79,939

	Number of Shares
	12/31/15		3/31/16
Nordson		347,237		60,710
Thermon		132,914		0
Consumer Goods & Services
Arctic Cat		271,406		0
Avis Budget Group		108,404		0
Blackhawk Network		287,811		0
Blue Nile		221,017		0
Casey's General Stores		42,508		0
Fiesta Restaurant Group		251,245		142,912
Fossil		85,078		0
Gaiam		199,584		0
Hertz		278,777		0
HRG Group		548,040		0
Knoll		400,817		292,470
Papa John's International		195,942		178,044
Quotient Technology		523,179		0
Select Comfort		394,935		0
The Chefs' Warehouse		75,815		0
The Fresh Market		331,772		0
Vail Resorts		84,270		68,547
Finance
Associated Banc-Corp		627,882		388,882
Guaranty Bancorp		173,244		0
Lakeland Financial		278,899		154,427
LegacyTexas		441,945		164,945
Leucadia National		255,302		0
MB Financial		554,175		213,244
McGrath Rentcorp		60,425		0
SEI Investments		150,993		139,704
SVB Financial Group		106,861		92,114
WEX		34,500		0
Other Industries
EdR		239,272		0
Extra Space Storage		263,366		61,844
Heartland Express		351,672		171,672
Rush Enterprises, Class A		142,789		0
Rush Enterprises, Class B		109,866		0
Energy & Minerals
SM Energy		106,304		0

45

COLUMBIA ACORN USA®

STATEMENT OF INVESTMENTS (UNAUDITED), MARCH 31, 2016

Number of Shares			Value
			Equities: 96.6%
Information 25.4%
		> Business Software 9.0%
	115,623	Ansys (a)	$	10,343,633
		Simulation Software for Engineers & Designers
	138,645	Guidewire (a)		7,553,379
		Software for Global Property & Casualty Insurance Carriers
	125,555	Manhattan Associates (a)		7,140,313
		Supply Chain Management Software & Services
	181,241	DemandWare (a)		7,086,523
		E-Commerce Website Platform for Retailers & Apparel Manufacturers
	330,297	NIC		5,955,255
		Government Web Portal Development & Management Outsourcing
	127,531	SPS Commerce (a)		5,476,181
		Supply Chain Management Software Delivered via the Web
	41,000	Tyler Technologies		5,273,010
		Financial, Tax, Court & Document Management Systems for Local Governments
	240,554	Cvent (a)		5,147,856
		Software for Corporate Event Planners & Marketing Platform for Hotels
	73,420	NetSuite (a)		5,028,536
		Enterprise Software Delivered via the Web
	134,390	Q2 Holdings		3,230,736
		Online & Mobile Banking Software
				62,235,422
		> Computer Services 4.6%
	202,933	ExlService Holdings (a)		10,511,929
		Business Process Outsourcing
	308,890	WNS - ADR (a)		9,464,389
		Offshore Business Process Outsourcing Services
	114,691	J2 Global Communications		7,062,672
		Communication Technology & Digital Media
	133,947	Virtusa (a)		5,017,655
		Offshore IT Outsourcing
				32,056,645
		> Instrumentation 3.2%
	39,769	Mettler-Toledo International (a)		13,710,760
		Laboratory Equipment
	90,760	IPG Photonics (a)		8,720,221
		Fiber Lasers
				22,430,981
		> Semiconductors & Related Equipment 2.2%
	115,412	Monolithic Power Systems		7,344,820
		High Performance Analog & Mixed Signal Integrated Circuits
	57,838	Littelfuse		7,120,436
		Little Fuses

Number of Shares			Value
	588,690	Rubicon Technology (a)(b)	$	429,744
		Producer of Sapphire for the Lighting, Electronics & Automotive Industries
				14,895,000
		> Financial Processors 1.7%
	97,431	Global Payments		6,362,244
		Credit Card Processor
	156,327	CoreLogic (a)		5,424,547
		Data Processing Services for Real Estate, Insurance & Mortgages
				11,786,791
		> Business Information & Marketing Services 1.5%
	105,287	Corporate Executive Board		6,815,228
		Best Practices Advisory & HR Solutions/Analytics
	230,578	Navigant Consulting (a)		3,645,438
		Financial Consulting Firm
				10,460,666
		> Telephone & Data Services 1.5%
	788,516	Lumos Networks (a)		10,124,546
		Telephone & Fiber Optic Data Services
		> Computer Hardware & Related Equipment 1.0%
	110,385	Rogers (a)		6,608,750
		Printed Circuit Materials & High Performance Foams
		> Telecommunications Equipment 0.7%
	251,287	CalAmp (a)		4,505,576
		Machine-to-machine Communications
Information: Total				175,104,377
Health Care 19.4%
		> Health Care Services 6.9%
	294,451	HealthSouth		11,080,191
		Inpatient Rehabilitation Facilities & Home Health Care
	304,182	AMN Healthcare Services (a)		10,223,557
		Temporary Healthcare Staffing
	244,664	Medidata Solutions (a)		9,470,943
		Cloud-based Software for Drug Studies
	130,320	Mednax (a)		8,421,278
		Physician Management for Pediatric & Anesthesia Practices
	141,000	Healthcare Services Group		5,190,210
		Outsourced Services to Long-Term Care Industry
	69,429	TeamHealth		2,902,827
		Healthcare Professionals Outsourcing
				47,289,006
		> Biotechnology & Drug Delivery 4.9%
	224,270	Seattle Genetics (a)		7,869,634
		Antibody-based Therapies for Cancer

46

Number of Shares			Value
		> Biotechnology & Drug Delivery—continued
	73,260	Ligand Pharmaceuticals (a)	$	7,845,413
		Royalties from Licensing Drug Delivery Technology
	278,000	Repligen		7,455,960
		Supplier to Biopharma Industry
	61,654	Ultragenyx Pharmaceutical (a)		3,903,315
		Biotech Focused on "Ultra-Orphan" Drugs
	140,418	Sarepta Therapeutics (a)		2,740,959
		Biotech Focused on Rare Diseases
	50,971	Agios Pharmaceuticals (a)(b)		2,069,423
		Biotech Focused on Cancer & Orphan Diseases
	14,121	Intercept Pharmaceuticals (a)(b)		1,814,125
		Biotech Developing Drugs for Several Diseases
				33,698,829
		> Medical Supplies 3.9%
	426,782	VWR (a)		11,548,721
		Distributor of Lab Supplies
	84,652	Bio-Techne		8,001,307
		Maker of Consumables & Systems for the Life Science Market
	109,000	West Pharmaceutical Services		7,555,880
		Components & Systems for Injectable Drug Delivery
				27,105,908
		> Medical Equipment & Devices 2.2%
	330,724	ZELTIQ Aesthetics		8,982,464
		Systems & Consumables for Aesthetics
	63,000	Abiomed (a)		5,973,030
		Medical Devices for Cardiac Conditions
	24,288	LeMaitre Vascular		376,950
		Medical Devices for Peripheral Vascular Disease
				15,332,444
		> Pharmaceuticals 1.5%
	133,313	Cambrex (a)		5,865,772
		Application Program Interface for Small Molecule Drugs
	186,441	Akorn (a)		4,386,957
		Developer, Manufacturer & Distributor of Specialty Generic Drugs
				10,252,729
Health Care: Total				133,678,916
Industrial Goods & Services 18.5%
		> Machinery 11.7%
	204,785	Toro		17,636,084
		Turf Maintenance Equipment
	254,107	ESCO Technologies		9,905,091
		Industrial Filtration & Advanced Measurement Equipment
	177,840	HEICO		8,465,184
		FAA-approved Aircraft Replacement Parts

Number of Shares			Value
	72,355	Middleby (a)	$	7,725,343
		Manufacturer of Cooking Equipment
	134,361	Dorman Products (a)		7,311,926
		Aftermarket Auto Parts Distributor
	212,114	Donaldson		6,768,558
		Industrial Air Filtration
	144,268	Oshkosh Corporation		5,896,233
		Specialty Truck Manufacturer
	99,071	Ametek		4,951,569
		Aerospace/Industrial Instruments
	60,710	Nordson		4,616,388
		Dispensing Systems for Adhesives & Coatings
	79,939	Moog (a)		3,651,614
		Motion Control Products for Aerospace, Defense & Industrial Markets
	89,922	Generac (a)		3,348,695
		Standby Power Generators
				80,276,685
		> Outsourcing Services 3.8%
	46,858	CoStar Group (a)		8,817,270
		Commercial Real Estate Data Aggregator & Web Marketing for Retail Landlords
	123,714	Maximus		6,512,305
		Outsourcer for Government Program Administration
	168,202	ServiceMaster		6,337,851
		Pest & Termite Control, Home Warranty & other Home Services
	154,643	Korn/Ferry International		4,374,851
		Executive Search & Corporate Leadership/Talent Consulting
				26,042,277
		> Industrial Materials & Specialty Chemicals 2.3%
	248,550	Drew Industries		16,021,533
		RV & Manufactured Home Components
		> Construction 0.7%
	509,561	PGT (a)		5,014,080
		Wind Resistant Windows & Doors
Industrial Goods & Services: Total				127,354,575
Consumer Goods & Services 17.9%
		> Other Durable Goods 4.1%
	146,863	Cavco Industries (a)		13,725,816
		Manufactured Homes
	184,443	Gentherm (a)		7,670,984
		Climate Control Systems for Car Seats, Mattresses & Other
	445,792	Gentex		6,994,477
		Manufacturer of Auto Parts
				28,391,277
		> Restaurants 3.9%
	178,044	Papa John's International		9,648,205
		Franchisor of Pizza Restaurants

47

COLUMBIA ACORN USA®

STATEMENT OF INVESTMENTS (UNAUDITED), CONTINUED

Number of Shares			Value
		> Restaurants—continued
	162,108	Texas Roadhouse	$	7,064,667
		Rural-focused Full Service Steakhouse
	135,576	Zoës Kitchen		5,286,108
		Fast, Casual Mediterranean Food
	142,912	Fiesta Restaurant Group (a)		4,684,655
		Owner/Operator of Two Restaurant Chains: Pollo Tropical & Taco Cabana
				26,683,635
		> Travel 3.2%
	68,547	Vail Resorts		9,164,734
		Ski Resort Operator & Developer
	162,663	Choice Hotels		8,791,935
		Franchisor of Budget Hotel Brands
	175,984	Liberty TripAdvisor Holdings Class A (a)		3,899,805
		Holding Company for Trip Advisor
				21,856,474
		> Retail 1.7%
	193,351	Cato		7,453,681
		Women's Apparel Retailing, Focusing on Private Labels & Low Prices
	103,839	Five Below (a)		4,292,704
		Low-price Specialty Retailer Targeting Pre-teens, Teens & Parents
				11,746,385
		> Other Consumer Services 1.4%
	91,054	Unifirst		9,935,812
		Uniform Rental
		> Leisure Products 1.4%
	194,023	Brunswick Corp		9,309,224
		Boats, Engines, Exercise & Bowling Equipment
		> Furniture & Textiles 0.9%
	292,470	Knoll		6,331,976
		Office & Residential Furniture
		> Consumer Goods Distribution 0.8%
	60,506	Pool		5,308,796
		Swimming Pool Supplies & Equipment Distributor
		> Consumer Electronics 0.5%
	104,190	iRobot (a)		3,677,907
		Home Robots (Vacuums, Pool Cleaners) & Battlefield Reconnaissance Robots
Consumer Goods & Services: Total				123,241,486
Finance 9.9%
		> Banks 5.5%
	92,114	SVB Financial Group (a)		9,400,234
		Bank to Venture Capitalists
	154,427	Lakeland Financial		7,069,668
		Indiana Bank

Number of Shares			Value
	388,882	Associated Banc-Corp	$	6,976,543
		Midwest Bank
	213,244	MB Financial		6,919,768
		Chicago Bank
	149,411	Sandy Spring Bancorp		4,158,108
		Baltimore & Washington, D.C. Bank
	163,102	First Busey		3,340,329
		Illinois Bank
				37,864,650
		> Brokerage & Money Management 3.3%
	81,054	MarketAxess		10,117,971
		Bond Exchange
	294,354	Virtu Financial		6,508,167
		High Speed Trader
	139,704	SEI Investments		6,014,257
		Mutual Fund Administration & Investment Management
				22,640,395
		> Insurance 0.6%
	129,214	Allied World Assurance Company Holdings		4,514,737
		Commercial Lines Insurance/ Reinsurance
		> Savings & Loans 0.5%
	164,945	LegacyTexas		3,241,169
		Texas Thrift
Finance: Total				68,260,951
Other Industries 2.8%
		> Real Estate 2.3%
	271,911	Colliers International Group		10,294,551
		Real Estate Services
	61,844	Extra Space Storage		5,779,940
		Self Storage Facilities
				16,074,491
		> Transportation 0.5%
	171,672	Heartland Express		3,184,515
		Regional Trucker
Other Industries: Total				19,259,006
Energy & Minerals 2.7%
		> Oil & Gas Producers 1.8%
	112,314	PDC Energy (a)		6,677,067
		Oil & Gas Producer in the United States
	195,854	Carrizo Oil & Gas (a)		6,055,806
		Oil & Gas Producer
				12,732,873
		> Mining 0.9%
	55,757	Core Labs (Netherlands)		6,267,644
		Oil & Gas Reservoir Consulting
Energy & Minerals: Total				19,000,517
Total Equities: 96.6% (Cost: $484,791,886)				665,899,828	(c)

48

Number of Shares			Value
Short-Term Investments 3.3%
	22,866,790	JPMorgan U.S. Government Money Market Fund, Agency Shares (7 day yield of 0.15%)	$	22,866,790
Total Short-Term Investments: 3.3% (Cost: $22,866,790)				22,866,790
Securities Lending Collateral 0.4%
	2,955,725	Dreyfus Government Cash Management Fund, Institutional Shares (7 day yield of 0.20%) (d)		2,955,725
Total Securities Lending Collateral: 0.4% (Cost: $2,955,725)				2,955,725
Total Investments: 100.3% (Cost: $510,614,401)(e)				691,722,343	(f)(g)
Obligation to Return Collateral for Securities Loaned: (0.4)%				(2,955,725	)
Cash and Other Assets Less Liabilities: 0.1%				953,819
Net Assets: 100.0%			$	689,720,437

ADR - American Depositary Receipts

> Notes to Statement of Investments

(a)  Non-income producing security.

(b)  All or a portion of this security was on loan at March 31, 2016. The total market value of securities on loan at March 31, 2016 was $2,997,748.

(c)  On March 31, 2016, the market value of foreign securities represented 0.91% of total net assets. The Fund's foreign portfolio was diversified as follows:

Country	Value		Percentage of Net Assets
Netherlands	$	6,267,644		0.91

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

(e)  At March 31, 2016, for federal income tax purposes, the cost of investments was approximately $510,614,401 and net unrealized appreciation was $181,107,942 consisting of gross unrealized appreciation of $201,492,801 and gross unrealized depreciation of $20,384,859.

(f)  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 March 31, 2016, are as follows:

Security	Balance of Shares Held 12/31/15		Purchases/ Additions		Sales/ Reductions		Balance of Shares Held 3/31/16		Value		Dividend
Rubicon Technology		1,354,071		-		765,381		588,690	$	429,744	$	-

  At March 31, 2016, the fund did not hold any investments in affiliated companies

(g)  Securities are valued using policies described in the Notes to Financial Statements in the shareholder report dated December 31, 2015.

49

COLUMBIA ACORN USA®

STATEMENT OF INVESTMENTS (UNAUDITED), CONTINUED

> Notes to Statement of Investments

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.

  The following table summarizes the inputs used, as of March 31, 2016, 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	$	175,104,377	$	-	$	-	$	175,104,377
Health Care		133,678,916		-		-		133,678,916
Industrial Goods & Services		127,354,575		-		-		127,354,575
Consumer Goods & Services		123,241,486		-		-		123,241,486
Finance		68,260,951		-		-		68,260,951
Other Industries		19,259,006		-		-		19,259,006
Energy & Minerals		19,000,517		-		-		19,000,517
Total Equities		665,899,828		-		-		665,899,828
Total Short-Term Investments		22,866,790		-		-		22,866,790
Total Securities Lending Collateral		2,955,725		-		-		2,955,725
Total Investments	$	691,722,343	$	-	$	-	$	691,722,343

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

50

COLUMBIA ACORN INTERNATIONAL SELECT^SM

MAJOR PORTFOLIO CHANGES IN THE FIRST QUARTER (UNAUDITED)

	Number of Shares
	12/31/15		3/31/16
Purchases
Europe
> United Kingdom
Compass Group		95,000		141,000
Next		14,000		38,000
Rightmove		0		54,000
> France
Essilor International		13,000		19,000
> Denmark
Novozymes		109,500		131,955
> Sweden
Hexagon		62,900		69,000
> Ireland
Ryanair		0		158,000
Asia
> Japan
Aeon Mall		160,000		246,000
Bandai Namco		0		126,800
FamilyMart		0		45,600
KDDI		116,000		134,000
> Taiwan
Largan Precision		37,000		41,000
> Thailand
Airports of Thailand		0		228,000

	Number of Shares
	12/31/15		3/31/16
Sales
Europe
> United Kingdom
Babcock International		215,000		0
WH Smith		125,000		92,930
Whitbread		24,000		0
> Germany
Telefonica Deutschland		785,500		717,400
> Switzerland
Partners Group		15,640		13,056
> Sweden
Swedish Match		98,701		0
> Spain
Distribuidora Internacional de Alimentación		790,000		477,000
> Netherlands
Vopak		72,000		0
Asia
> Japan
Japan Tobacco		57,200		0
Recruit Holdings		118,000		77,300
Secom		43,000		0
Sony Financial Holdings		269,000		254,400
> Korea
CJ Corp		9,857		4,168
KT&G		22,700		0
Samsung Fire & Marine Preferred		6,354		0
Samsung Fire and Marine		3,900		0
> Hong Kong
Hong Kong Exchanges and Clearing		123,726		0
> Singapore
Singapore Exchange		612,000		0
Other Countries
> Canada
Vermilion Energy		111,000		29,240
> United States
Anadarko Petroleum		62,000		41,840

51

COLUMBIA ACORN INTERNATIONAL SELECT^SM

STATEMENT OF INVESTMENTS (UNAUDITED), MARCH 31, 2016

Number of Shares			Value
			Equities: 96.8%
Europe 46.6%
		> United Kingdom 11.7%
	54,000	Rightmove	$	3,265,945
		Internet Real Estate Listings
	38,000	Next		2,947,183
		Clothes & Home Retailer in the UK
	178,000	Smith & Nephew		2,934,889
		Medical Equipment & Supplies
	141,000	Compass Group		2,486,837
		Catering & Support Services
	92,930	WH Smith		2,426,496
		Newsprint, Books & General Stationery Retailer
				14,061,350
		> Germany 9.3%
	115,000	Wirecard (a)		4,357,587
		Online Payment Processing & Risk Management
	717,400	Telefonica Deutschland		3,886,544
		Mobile & Fixed-line Communications in Germany
	29,500	MTU Aero Engines		2,829,451
		Airplane Engine Components & Services
				11,073,582
		> Switzerland 7.0%
	13,056	Partners Group		5,247,927
		Private Markets Asset Management
	8,540	Geberit		3,191,120
		Plumbing Systems
				8,439,047
		> France 5.0%
	112,250	Eutelsat		3,626,234
		Fixed Satellite Services
	19,000	Essilor International		2,346,861
		Eyeglass Lenses
				5,973,095
		> Denmark 5.0%
	131,955	Novozymes		5,932,283
		Industrial Enzymes
		> Sweden 4.4%
	69,000	Hexagon		2,685,801
		Design, Measurement & Visualization Software & Equipment
	79,000	Hennes & Mauritz		2,634,225
		Discount Fashion Retailer
				5,320,026
		> Ireland 2.1%
	158,000	Ryanair		2,546,699
		European Low Cost Airline

Number of Shares			Value
		> Spain 2.1%
	477,000	Distribuidora Internacional de Alimentación	$	2,478,325
		Discount Retailer in Spain & Latin America
Europe: Total				55,824,407
Asia 33.7%
		> Japan 19.3%
	246,000	Aeon Mall		3,639,616
		Suburban Shopping Mall Developer, Owner & Operator
	134,000	KDDI		3,575,225
		Mobile & Fixed Line Communication Service Provider in Japan
	254,400	Sony Financial Holdings		3,252,914
		Life Insurance, Assurance & Internet Banking
	126,800	Bandai Namco		2,764,039
		Branded Toys & Related Content
	173,000	Santen Pharmaceutical		2,600,273
		Specialty Pharma (Ophthalmic Medicine)
	68,000	Hoya Corp		2,584,723
		Opto-electrical Components & Eyeglass Lenses
	45,600	FamilyMart		2,368,257
		Convenience Store Operator
	77,300	Recruit Holdings		2,356,929
		Recruitment & Media Services
				23,141,976
		> Taiwan 5.3%
	41,000	Largan Precision		3,177,874
		Mobile Device Camera Lenses & Modules
	1,400,000	Far EasTone Telecom		3,135,543
		Mobile Operator in Taiwan
				6,313,417
		> China 4.1%
	2,191,000	China Everbright International		2,446,756
		Municipal Waste Operator
	17,000	NetEase.com - ADR		2,440,860
		Chinese Online Gaming Services
				4,887,616
		> India 2.2%
	463,000	Zee Entertainment Enterprises		2,704,598
		Indian Programmer of Pay Television Content
		> Thailand 2.2%
	228,000	Airports of Thailand		2,602,950
		Airport Operator of Thailand
		> Korea 0.6%
	4,168	CJ Corp		712,642
		Holding Company of Korean Consumer Conglomerate
Asia: Total				40,363,199

52

Number of Shares			Value
Other Countries 15.9%
		> Canada 6.2%
	34,641	CCL Industries	$	6,574,788
		Global Label Converter
	29,240	Vermilion Energy (a)		855,756
		Canadian Exploration & Production Company
				7,430,544
		> Australia 5.6%
	305,000	Amcor		3,349,226
		Global Leader in Flexible & Rigid Packaging
	778,268	IAG		3,323,905
		General Insurance Provider
				6,673,131
		> South Africa 2.5%
	21,000	Naspers		2,931,572
		Media in Africa, China, Russia & other Emerging Markets
		> United States 1.6%
	41,840	Anadarko Petroleum		1,948,489
		Worldwide Production of Oil & Gas
Other Countries: Total				18,983,736
Latin America 0.6%
		> Uruguay 0.6%
	191,666	Union Agriculture Group (b)(c)(d)		684,248
		Farmland Operator in Uruguay
Latin America: Total				684,248
Total Equities: 96.8% (Cost: $102,102,763)				115,855,590	(e)

Number of Shares			Value
Short-Term Investments 3.9%
	4,646,816	JPMorgan U.S. Government Money Market Fund, IM Shares (7 day yield of 0.25%)	$	4,646,816
Total Short-Term Investments: 3.9% (Cost: $4,646,816)				4,646,816
Securities Lending Collateral 2.2%
	2,628,500	Dreyfus Government Cash Management Fund, Institutional Shares (7 day yield of 0.20%) (f)		2,628,500
Total Securities Lending Collateral: 2.2% (Cost: $2,628,500)				2,628,500
Total Investments: 102.9% (Cost: $109,378,079)(g)				123,130,906	(h)
Obligation to Return Collateral for Securities Loaned: (2.2)%				(2,628,500	)
Cash and Other Assets Less Liabilities: (0.7)%				(884,672	)
Net Assets: 100.0%			$	119,617,734

ADR - American Depositary Receipts

> Notes to Statement of Investments

(a)  All or a portion of this security was on loan at March 31, 2016. The total market value of securities on loan at March 31, 2016 was $2,523,029.

(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 March 31, 2016, the market value of this security amounted to $684,248, which represented 0.57% of total net assets. Additional information on this security is as follows:

Security	Acquisition Dates	Shares		Cost		Value
Union Agriculture Group	12/8/10-6/27/12		191,666	$	2,200,000	$	684,248

(d)  Illiquid security.

53

COLUMBIA ACORN INTERNATIONAL SELECT^SM

STATEMENT OF INVESTMENTS (UNAUDITED), CONTINUED

> Notes to Statement of Investments

(e)  On March 31, 2016, the Fund's total equity investments were denominated in currencies as follows:

Currency	Value		Percentage of Net Assets
Japanese Yen	$	23,141,976		19.3
Euro		22,071,701		18.5
British Pound		14,061,350		11.7
Swiss Franc		8,439,047		7.0
Canadian Dollar		7,430,544		6.2
Australian Dollar		6,673,131		5.6
Taiwan Dollar		6,313,417		5.3
Danish Krone		5,932,283		5.0
Other currencies less than 5% of total net assets		21,792,141		18.2
Total Equities	$	115,855,590		96.8

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

(g)  At March 31, 2016, for federal income tax purposes, the cost of investments was approximately $109,378,079 and net unrealized appreciation was $13,752,827 consisting of gross unrealized appreciation of $21,813,076 and gross unrealized depreciation of $8,060,249.

(h)  Securities are valued using policies described in the Notes to Financial Statements in the shareholder report dated December 31, 2015.

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.

54

> Notes to Statement of Investments

  The following table summarizes the inputs used, as of March 31, 2016, 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	$	-	$	55,824,407	$	-	$	55,824,407
Asia		2,440,860		37,922,339		-		40,363,199
Other Countries		9,379,033		9,604,703		-		18,983,736
Latin America		-		-		684,248		684,248
Total Equities		11,819,893		103,351,449		684,248		115,855,590
Total Short-Term Investments		4,646,816		-		-		4,646,816
Total Securities Lending Collateral		2,628,500		-		-		2,628,500
Total Investments	$	19,095,209	$	103,351,449	$	684,248	$	123,130,906

  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 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.

55

COLUMBIA ACORN INTERNATIONAL SELECT^SM

PORTFOLIO DIVERSIFICATION (UNAUDITED)

At March 31, 2016, the Fund's portfolio investments as a percentage of net assets were diversified as follows:

	Value		Percentage of Net Assets
> Information
Internet Related	$	8,638,377		7.2
Mobile Communications		6,710,768		5.6
Financial Processors		4,357,587		3.6
Telephone & Data Services		3,886,544		3.3
Satellite Broadcasting & Services		3,626,234		3.0
Telecommunications Equipment		3,177,874		2.7
Entertainment Programming		2,704,598		2.3
Business Software		2,685,801		2.2
Semiconductors & Related Equipment		2,584,723		2.2
Advertising		2,356,929		2.0
		40,729,435		34.1
> Consumer Goods & Services
Retail		12,854,488		10.7
Nondurables		6,574,788		5.5
Leisure Products		2,764,039		2.3
Restaurants		2,486,837		2.1
		24,680,152		20.6
> Industrial Goods & Services
Industrial Materials & Specialty Chemicals		9,281,508		7.7
Construction		3,191,120		2.7
Other Industrial Services		2,829,451		2.4
Waste Management		2,446,756		2.0
Conglomerates		712,642		0.6
		18,461,477		15.4
> Finance
Insurance		6,576,819		5.5
Brokerage & Money Management		5,247,927		4.4
		11,824,746		9.9

	Value			Percentage of Net Assets
> Other Industries
Transportation	$	5,149,649			4.3
Real Estate		3,639,616			3.0
		8,789,265			7.3
> Health Care
Medical Equipment & Devices		5,281,750			4.4
Pharmaceuticals		2,600,273			2.2
		7,882,023			6.6
> Energy & Minerals
Oil & Gas Producers		2,804,244			2.3
Agricultural Commodities		684,248			0.6
		3,488,492			2.9
Total Equities:		115,855,590			96.8
Short-Term Investments:		4,646,816			3.9
Securities Lending Collateral:		2,628,500			2.2
Total Investments:		123,130,906			102.9
Obligation to Return Collateral for Securities Loaned:		(2,628,500	)		(2.2	)
Cash and Other Assets Less Liabilities:		(884,672	)		(0.7	)
Net Assets:	$	119,617,734			100.0

56

COLUMBIA ACORN SELECT^SM

MAJOR PORTFOLIO CHANGES IN THE FIRST QUARTER (UNAUDITED)

	Number of Shares
	12/31/15		3/31/16
Purchases
Industrial Goods & Services
Generac		328,030		367,030
Middleby		0		60,000
Robert Half International		224,395		270,395
Consumer Goods & Services
HRG Group		0		1,085,000
iRobot		0		370,000
Liberty TripAdvisor Holdings Class A		0		300,000
Papa John's International		122,000		225,500
Select Comfort		185,000		361,665
Information
Liberty Global Series A		0		354,000
Health Care
HealthSouth		0		267,000
VWR		257,603		317,603
Other Industries
Heartland Express		181,000		407,000
Jones Lang LaSalle		0		46,200
Finance
SVB Financial Group		0		116,000

	Number of Shares
	12/31/15		3/31/16
Sales
Industrial Goods & Services
Donaldson		320,657		244,657
Expeditors International of Washington		291,687		210,387
LKQ		703,620		588,620
Quanta Services		164,292		0
Consumer Goods & Services
Blackhawk Network		241,795		0
Fossil		217,636		0
Gentex		556,000		357,000
Polaris Industries		140,550		110,550
The Fresh Market		449,697		0
Vail Resorts		150,306		99,584
Information
Bankrate		983,300		0
F5 Networks		120,347		0
Vonage		1,421,481		618,778
WNS - ADR		297,876		0
Other Industries
Extra Space Storage		109,626		62,426
Finance
Associated Banc-Corp		594,605		0
CNO Financial Group		677,866		0
SEI Investments		138,751		0
WEX		45,000		0
Energy & Minerals
Core Labs (Netherlands)		70,299		0

57

COLUMBIA ACORN SELECT^SM

STATEMENT OF INVESTMENTS (UNAUDITED), MARCH 31, 2016

Number of Shares			Value
			Equities: 97.4%
Industrial Goods & Services 29.5%
		> Machinery 15.7%
	202,256	Nordson	$	15,379,547
		Dispensing Systems for Adhesives & Coatings
	299,000	Ametek		14,944,020
		Aerospace/Industrial Instruments
	367,030	Generac (a)(b)		13,668,197
		Standby Power Generators
	244,657	Donaldson		7,807,005
		Industrial Air Filtration
	60,000	Middleby (a)		6,406,200
		Manufacturer of Cooking Equipment
				58,204,969
		> Other Industrial Services 11.3%
	588,620	LKQ (a)		18,794,637
		Alternative Auto Parts Distribution
	270,395	Robert Half International		12,594,999
		Temporary & Permanent Staffing in Finance, Accounting & other Professions
	210,387	Expeditors International of Washington		10,268,989
		International Freight Forwarder
				41,658,625
		> Industrial Materials & Specialty Chemicals 2.5%
	320,681	Axalta Coating Systems (a)		9,363,885
		Leading Global Manufacturer of High Performance Coatings
Industrial Goods & Services: Total				109,227,479
Consumer Goods & Services 22.7%
		> Travel 5.4%
	99,584	Vail Resorts		13,314,381
		Ski Resort Operator & Developer
	300,000	Liberty TripAdvisor Holdings Class A (a)		6,648,000
		Holding Company for Trip Advisor
				19,962,381
		> Nondurables 4.1%
	1,085,000	HRG Group (a)		15,114,050
		Holding Company
		> Consumer Electronics 3.5%
	370,000	iRobot (a)		13,061,000
		Home Robots (Vacuums, Pool Cleaners) & Battlefield Reconnaissance Robots
		> Other Durable Goods 3.4%
	361,665	Select Comfort (a)		7,012,684
		Specialty Mattresses
	357,000	Gentex		5,601,330
		Manufacturer of Auto Parts
				12,614,014
		> Restaurants 3.3%
	225,500	Papa John's International		12,219,845
		Franchisor of Pizza Restaurants

Number of Shares			Value
		> Leisure Products 3.0%
	110,550	Polaris Industries	$	10,886,964
		Leisure Vehicles & Related Products
Consumer Goods & Services: Total				83,858,254
Information 16.6%
		> Business Software 4.8%
	113,158	Ansys (a)		10,123,115
		Simulation Software for Engineers & Designers
	40,057	Ultimate Software (a)		7,751,029
		Human Capital Management Systems
				17,874,144
		> Mobile Communications 4.0%
	171,161	Crown Castle International		14,805,427
		Communications Towers
		> Cable TV 3.7%
	354,000	Liberty Global Series A (a)		13,629,000
		Cable TV Franchises Outside of the United States
		> Computer Hardware & Related Equipment 3.3%
	214,095	Amphenol		12,378,973
		Electronic Connectors
		> Internet Related 0.8%
	618,778	Vonage (a)		2,827,815
		Business & Consumer Internet Telephony
Information: Total				61,515,359
Health Care 11.8%
		> Medical Supplies 4.5%
	317,603	VWR (a)		8,594,337
		Distributor of Lab Supplies
	242,166	Cepheid (a)		8,078,658
		Molecular Diagnostics
				16,672,995
		> Medical Equipment & Devices 4.1%
	207,927	Align Technology (a)		15,114,213
		Invisalign System to Correct Malocclusion (Crooked Teeth)
		> Health Care Services 2.7%
	267,000	HealthSouth		10,047,210
		Inpatient Rehabilitation Facilities & Home Health Care
		> Biotechnology & Drug Delivery 0.5%
	26,186	Ultragenyx Pharmaceutical (a)		1,657,836
		Biotech Focused on "Ultra-Orphan" Drugs
Health Care: Total				43,492,254
Other Industries 9.3%
		> Real Estate 7.3%
	375,266	EdR		15,611,066
		Student Housing
	62,426	Extra Space Storage		5,834,334
		Self Storage Facilities

58

Number of Shares			Value
		> Real Estate—continued
	46,200	Jones Lang LaSalle	$	5,420,184
		Real Estate Services
				26,865,584
		> Transportation 2.0%
	407,000	Heartland Express		7,549,850
		Regional Trucker
Other Industries: Total				34,415,434
Finance 5.8%
		> Banks 3.2%
	116,000	SVB Financial Group (a)		11,837,800
		Bank to Venture Capitalists
		> Brokerage & Money Management 2.6%
	286,237	Eaton Vance		9,594,664
		Specialty Mutual Funds
Finance: Total				21,432,464
Energy & Minerals 1.7%
		> Agricultural Commodities 1.7%
	1,742,424	Union Agriculture Group (Uruguay) (a)(c)(d)		6,220,454
		Farmland Operator in Uruguay
Energy & Minerals: Total				6,220,454
Total Equities: 97.4% (Cost: $313,623,128)				360,161,698	(e)

Number of Shares			Value
Short-Term Investments 2.3%
	8,493,737	JPMorgan U.S. Government Money Market Fund, Agency Shares (7 day yield of 0.15%)	$	8,493,737
Total Short-Term Investments: 2.3% (Cost: $8,493,737)				8,493,737
Securities Lending Collateral 0.8%
	2,972,200	Dreyfus Government Cash Management Fund, Institutional Shares (7 day yield of 0.20%) (f)		2,972,200
Total Securities Lending Collateral: 0.8% (Cost: $2,972,200)				2,972,200
Total Investments: 100.5% (Cost: $325,089,065)(g)				371,627,635	(h)
Obligation to Return Collateral for Securities Loaned: (0.8)%				(2,972,200	)
Cash and Other Assets Less Liabilities: 0.3%				994,523
Net Assets: 100.0%			$	369,649,958

ADR - American Depository Receipts

> Notes to Statement of Investments

(a)  Non-income producing security.

(b)  All or a portion of this security was on loan at March 31, 2016. The total market value of securities on loan at March 31, 2016 was $2,874,928.

(c)  Illiquid security.

(d)  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 March 31, 2016, the market value of this security amounted to $6,220,454, which represented 1.68% of total net assets. Additional information on this security is as follows:

Security	Acquisition Dates	Shares		Cost		Value
Union Agriculture Group	12/8/10-6/27/12		1,742,424	$	20,000,000	$	6,220,454

(e)  On March 31, 2016, the market value of foreign securities represented 1.68% of total net assets. The Fund's foreign portfolio was diversified as follows:

Country	Value		Percentage of Net Assets
Uruguay	$	6,220,454		1.68

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

(g)  At March 31, 2016, for federal income tax purposes, the cost of investments was approximately $325,089,065 and net unrealized appreciation was $46,538,570 consisting of gross unrealized appreciation of $66,462,791 and gross unrealized depreciation of $19,924,221.

(h)  Securities are valued using policies described in the Notes to Financial Statements in the shareholder report dated December 31, 2015.

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)

59

COLUMBIA ACORN SELECT^SM

STATEMENT OF INVESTMENTS (UNAUDITED), CONTINUED

> Notes to Statement of Investments

•  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.

  The following table summarizes the inputs used, as of March 31, 2016, 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	$	109,227,479	$	-	$	-	$	109,227,479
Consumer Goods & Services		83,858,254		-		-		83,858,254
Information		61,515,359		-		-		61,515,359
Health Care		43,492,254		-		-		43,492,254
Other Industries		34,415,434		-		-		34,415,434
Finance		21,432,464		-		-		21,432,464
Energy & Minerals		-		-		6,220,454		6,220,454
Total Equities		353,941,244		-		6,220,454		360,161,698
Total Short-Term Investments		8,493,737		-		-		8,493,737
Total Securities Lending Collateral		2,972,200		-		-		2,972,200
Total Investments	$	365,407,181	$	-	$	6,220,454	$	371,627,635

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

  The following table reconciles asset balances for the period ending March 31, 2016, in which significant observable and/or unobservable inputs (Level 3) were used in determining value:

Investments in Securities	Balance as of December 31, 2015		Realized Gain (Loss)		Change in Unrealized Appreciation (Depreciation)			Purchases		Sales		Transfers Into Level 3		Transfers out of Level 3		Balance as of March 31, 2016
Equities
Energy & Minerals	$	8,851,514	$	-	$	(2,631,060	)	$	-	$	-	$	-	$	-	$	6,220,454

  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.

60

> Notes to Statement of Investments

  The change in unrealized depreciation attributed to securities owned at March 31, 2016, which were valued using significant unobservable inputs (Level 3), amounted to $2,631,060.

  Quantitative information pertaining to Level 3 unobservable fair value measurements

	Fair Value at March 31, 2016		Valuation Technique(s)	Unobservable Input(s)	Range (Weighted Average)
Equities
Energy & Minerals	$	6,220,454	Market comparable companies	Discount for lack of marketability		40	% to 65%

  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.

61

COLUMBIA THERMOSTAT FUND^SM

STATEMENT OF INVESTMENTS (UNAUDITED), MARCH 31, 2016

Number of Shares			Value
		> Affiliated Bond Funds 74.4%
	33,692,618	Columbia Short Term Bond Fund, Class I Shares (a)	$	335,241,548
	18,468,368	Columbia Total Return Bond Fund, Class I Shares (a)		168,431,517
	30,693,306	Columbia U.S. Government Mortgage Fund, Class I Shares (a)		167,585,452
	17,709,556	Columbia Income Opportunities Fund, Class I Shares (a)		167,001,112
Total Affiliated Bond Funds: (Cost: $839,940,913)				838,259,629
		> Affiliated Stock Funds 25.0%
	1,443,462	Columbia Acorn International, Class I Shares (a)		56,612,578
	2,658,168	Columbia Contrarian Core Fund, Class I Shares (a)		56,246,845
	3,100,829	Columbia Dividend Income Fund, Class I Shares (a)		56,093,991
	1,865,478	Columbia Acorn Select, Class I Shares (a)(b)		28,560,462
	1,497,687	Columbia Acorn Fund, Class I Shares (a)(b)		28,306,286

Number of Shares			Value
	1,870,262	Columbia Select Large Cap Growth Fund, Class I Shares (a)(b)	$	28,128,743
	1,341,094	Columbia Large Cap Enhanced Core Fund, Class I Shares (a)		28,042,275
Total Affiliated Stock Funds: (Cost: $246,958,056)				281,991,180
		> Short-Term Investments 0.5%
	5,569,606	JPMorgan U.S. Government Money Market Fund, Agency Shares (7 day yield of 0.15%)		5,569,606
Total Short-Term Investments: (Cost: $5,569,606)				5,569,606
Total Investments: 99.9% (Cost: $1,092,468,575)(c)				1,125,820,415	(d)
Cash and Other Assets Less Liabilities: 0.1%				605,805
Net Assets: 100.0%			$	1,126,426,220

> 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 March 31, 2016, are as follows:

Security	Balance of Shares Held 12/31/15		Purchases/ Additions		Sales/ Reductions		Balance of Shares Held 3/31/16		Value		Dividend
Columbia Short Term Bond Fund, Class I Shares		33,379,127		8,403,132		8,089,641		33,692,618	$	335,241,548	$	568,150
Columbia Total Return Bond Fund, Class I Shares		18,493,046		4,571,959		4,596,637		18,468,368		168,431,517		950,333
Columbia U.S. Government Mortgage Fund, Class I Shares		30,509,848		7,627,238		7,443,780		30,693,306		167,585,452		925,926
Columbia Income Opportunities Fund, Class I Shares		17,570,413		3,612,202		3,473,059		17,709,556		167,001,112		1,938,290
Columbia Acorn International, Class I Shares		1,389,031		1,000,088		945,657		1,443,462		56,612,578		-
Columbia Contrarian Core Fund, Class I Shares		2,628,205		1,799,359		1,769,396		2,658,168		56,246,845		-
Columbia Dividend Income Fund, Class I Shares		3,143,436		1,933,932		1,976,539		3,100,829		56,093,991		336,651
Columbia Acorn Select, Class I Shares		1,752,426		1,404,730		1,291,678		1,865,478		28,560,462		-
Columbia Acorn Fund, Class I Shares		1,397,374		1,166,019		1,065,706		1,497,687		28,306,286		-
Columbia Select Large Cap Growth Fund, Class I Shares		1,625,974		1,631,931		1,387,643		1,870,262		28,128,743		-
Columbia Large Cap Enhanced Core Fund, Class I Shares		1,322,181		939,721		920,808		1,341,094		28,042,275		-
Total of Affiliated Transactions		113,211,061		34,090,311		32,960,544		114,340,828	$	1,120,250,809	$	4,719,350

  The aggregate cost and value of these companies at March 31, 2016, was $1,086,898,969 and $1,120,250,809, respectively. Investments in affiliated companies represented 99.45% of the Fund's total net assets at March 31, 2016.

(b)  Non-income producing security.

(c)  At March 31, 2016, for federal income tax purposes, the cost of investments was approximately $1,092,468,575 and net unrealized appreciation was $33,351,840 consisting of gross unrealized appreciation of $36,920,244 and gross unrealized depreciation of $3,568,404.

(d)  Securities are valued using policies described in the Notes to Financial Statements in the shareholder report dated December 31, 2015.

62

> Notes to Statement of Investments

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 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 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.

  The following table summarizes the inputs used, as of March 31, 2016, 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	$	838,259,629	$	-	$	-	$	838,259,629
Total Affiliated Stock Funds		281,991,180		-		-		281,991,180
Total Short-Term Investments		5,569,606		-		-		5,569,606
Total Investments	$	1,125,820,415	$	-	$	-	$	1,125,820,415

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

63

COLUMBIA ACORN EMERGING MARKETS FUND^SM

MAJOR PORTFOLIO CHANGES IN THE FIRST QUARTER (UNAUDITED)

	Number of Shares
	12/31/15		3/31/16
Purchases
Asia
> China
Sihuan Pharmaceutical Holdings Group		11,951,000		14,400,000
> Taiwan
Addcn Technology		0		185,000
> Korea
CJ Corp		0		8,935
ModeTour Network		0		192,387
Sam Yung Trading		0		64,200
> India
Amara Raja		110,352		213,618
TVS Motor		0		363,631
> Thailand
Samui Airport Property Fund		5,562,800		6,819,100
> Cambodia
Nagacorp		4,715,000		5,697,000
Other Countries
> South Africa
Famous Brands		0		126,219
Latin America
> Guatemala
Tahoe Resources		0		209,464

	Number of Shares
	12/31/15		3/31/16
Sales
Asia
> China
51job - ADR		108,000		66,084
AMVIG Holdings		8,032,000		7,238,000
BitAuto - ADR		158,613		96,453
CAR Inc		1,806,000		0
China Everbright International		2,488,000		2,063,000
Jiangnan Group		12,978,000		0
Phoenix Healthcare Group		434,000		0
TravelSky Technology		2,294,000		1,275,000
> Taiwan
Advantech		445,988		293,988
Far EasTone Telecom		4,483,000		2,233,000
Ginko International		340,000		248,000
Largan Precision		49,000		27,000
Novatek Microelectronics		814,000		496,000
Silergy		431,000		233,000
St. Shine Optical		200,000		137,000
Vanguard International Semiconductor		2,621,000		1,310,000
Voltronic Power		190,156		0
> Korea
KCC		15,800		7,200
Koh Young Technology		241,088		126,435
Nongshim Holdings		49,594		30,938
> India
Adani Ports & Special Economic Zone		1,197,269		987,198
Bharti Infratel		730,342		510,298
Colgate Palmolive India		253,700		0
Container Corporation of India		175,000		0
United Breweries		318,483		195,277
Zee Entertainment Enterprises		2,025,982		1,252,443
> Indonesia
Link Net		22,000,000		16,359,100
Surya Citra Media		15,000,000		0
Tower Bersama Infrastructure		5,900,000		4,367,300
> Philippines
Puregold Price Club		6,304,200		3,771,300
RFM Corporation		56,400,000		32,000,000
Robinsons Retail Holdings		2,150,090		0
> Hong Kong
Value Partners		2,388,000		2,293,000
> Singapore
Petra Foods		1,386,000		488,000
SIIC Environment		5,400,000		4,815,800

64

	Number of Shares
	12/31/15		3/31/16
Sales (continued)
Asia—continued
> Thailand
Mega Lifesciences		5,350,000		0
> Malaysia
7-Eleven Malaysia Holdings		9,021,000		0
Other Countries
> South Africa
Coronation Fund Managers		945,899		497,334
Rand Merchant Insurance		1,294,495		973,864
> Egypt
Commercial International Bank of Egypt		1,219,988		904,583
> United States
Bladex		173,000		118,528
> Canada
Parex Resources		400,000		285,904
Latin America
> Mexico
Hoteles City Express		4,930,000		3,456,900
Qualitas		3,748,000		2,309,000
> Brazil
Linx		280,000		0
Localiza Rent a Car		595,970		0
Europe
> Finland
Tikkurila		355,260		223,246
> Spain
Prosegur		752,000		414,753
> Kazakhstan
Halyk Savings Bank of Kazakhstan - GDR		990,483		548,483
> Sweden
Millicom International Cellular		49,000		41,183
> United Kingdom
Cable and Wireless		3,180,134		0
PureCircle		736,860		369,998

65

COLUMBIA ACORN EMERGING MARKETS FUND^SM

STATEMENT OF INVESTMENTS (UNAUDITED), MARCH 31, 2016

Number of Shares			Value
			Equities: 96.0%
Asia 73.3%
		> China 13.1%
	12,200,000	NewOcean Energy	$	4,390,767
		Southern China Liquefied Petroleum Gas Distributor
	14,400,000	Sihuan Pharmaceutical Holdings Group		4,120,995
		Chinese Generic Drug Manufacturer
	4,380,000	Xinhua Winshare Publishing		3,799,019
		Sichuan Publisher, Distributor & Retailer
	7,238,000	AMVIG Holdings		3,022,558
		Chinese Tobacco Packaging Material Supplier
	96,453	BitAuto - ADR (a)		2,391,070
		Automotive Information Website for Buyers & Dealers
	2,063,000	China Everbright International		2,303,814
		Municipal Waste Operator
	1,275,000	TravelSky Technology		2,090,280
		Chinese Air Travel Transaction Processor
	66,084	51job - ADR (a)(b)		2,049,926
		Integrated Human Resource Services
				24,168,429
		> Taiwan 12.6%
	2,233,000	Far EasTone Telecom		5,001,192
		Mobile Operator in Taiwan
	233,000	Silergy		3,181,035
		Chinese Provider of Analog & Mixed Digital Integrated Circuits
	137,000	St. Shine Optical		2,793,425
		Disposable Contact Lens Original Equipment Manufacturer
	248,000	Ginko International		2,473,693
		Contact Lens Maker in China
	293,988	Advantech		2,160,379
		Industrial PC & Components
	27,000	Largan Precision		2,092,746
		Mobile Device Camera Lenses & Modules
	1,310,000	Vanguard International Semiconductor		2,046,599
		Semiconductor Foundry
	496,000	Novatek Microelectronics		1,996,618
		Display-related Integrated Circuit Designer
	185,000	Addcn Technology		1,494,308
		Largest Real Estate, Online Game Items & Auto Portal
				23,239,995
		> Korea 12.4%
	192,387	ModeTour Network		5,063,647
		Travel Services
	126,435	Koh Young Technology		4,515,584
		Inspection Systems for Printed Circuit Boards
	30,938	Nongshim Holdings		4,101,381
		Holding Company of Food Conglomerate

Number of Shares			Value
	95,600	Korea Investment Holdings	$	3,677,328
		Brokerage & Asset Management
	7,200	KCC		2,617,808
		Paint & Housing Material Manufacturer
	8,935	CJ Corp		1,527,700
		Holding Company of Korean Consumer Conglomerate
	64,200	Sam Yung Trading		1,345,717
		Opthalmic Lenses
				22,849,165
		> India 11.4%
	1,252,443	Zee Entertainment Enterprises		7,316,103
		Indian Programmer of Pay Television Content
	987,198	Adani Ports & Special Economic Zone		3,691,049
		Indian Ports
	510,298	Bharti Infratel		2,943,173
		Communications Towers
	213,618	Amara Raja		2,830,974
		Indian Maker of Auto & Industrial Batteries, mostly for the Replacement Market
	195,277	United Breweries		2,439,032
		Indian Brewer
	363,631	TVS Motor		1,772,669
		Indian Maker of Scooters, Mopeds, Motorcycles & Three-wheelers
				20,993,000
		> Indonesia 8.1%
	16,359,100	Link Net (a)		5,062,959
		Fixed Broadband & CATV Service Provider
	59,073,000	MNC Sky Vision (a)		4,945,025
		Satellite Pay TV Operator in Indonesia
	2,187,100	Matahari Department Store		3,026,434
		Department Store Chain in Indonesia
	4,367,300	Tower Bersama Infrastructure (a)		1,914,793
		Communications Towers
				14,949,211
		> Philippines 4.5%
	3,771,300	Puregold Price Club		2,981,329
		Supermarket Operator in the Philippines
	32,000,000	RFM Corporation		2,884,466
		Flour, Bread, Pasta & Ice Cream Manufacturer/Distributor in the Philippines
	44,882,000	Melco Crown (Philippines) Resorts (a)		2,465,591
		Integrated Resort Operator in Manila
				8,331,386
		> Hong Kong 3.5%
	2,100,000	Vitasoy International		3,921,657
		Hong Kong Soy Food Brand
	2,293,000	Value Partners		2,407,770
		Mutual Fund Management
				6,329,427

66

Number of Shares			Value
		> Singapore 3.2%
	4,815,800	SIIC Environment (a)	$	2,445,219
		Waste Water Treatment Operator
	6,500,000	China Everbright Water (a)		2,388,731
		Waste Water Treatment Operator
	488,000	Petra Foods		1,013,763
		Chocolate Manufacturer in Southeast Asia
				5,847,713
		> Thailand 2.5%
	6,819,100	Samui Airport Property Fund		4,613,263
		Thai Airport Operator
		> Cambodia 2.0%
	5,697,000	Nagacorp		3,650,719
		Casino & Entertainment Complex in Cambodia
Asia: Total				134,972,308
Other Countries 8.4%
		> South Africa 3.4%
	973,864	Rand Merchant Insurance		2,745,388
		Directly Sold Property & Casualty Insurance; Holdings in other Insurers
	497,334	Coronation Fund Managers		2,472,564
		South African Fund Manager
	126,219	Famous Brands		999,407
		Quick Service Restaurant & Cafe Franchise System in Africa
				6,217,359
		> Egypt 2.1%
	904,583	Commercial International Bank of Egypt		3,909,695
		Leading Private Universal Bank in Egypt
		> United States 1.6%
	118,528	Bladex		2,870,748
		Latin American Trade Financing House
		> Canada 1.3%
	285,904	Parex Resources (a)		2,410,510
		Canadian Listed Exploration & Production Company Operating in Colombia
Other Countries: Total				15,408,312
Latin America 7.3%
		> Mexico 6.1%
	28,795	Grupo Aeroportuario del Sureste - ADR		4,324,145
		Mexican Airport Operator
	3,456,900	Hoteles City Express (a)		4,251,808
		Leading Budget Hotel Operator in Mexico
	2,309,000	Qualitas (a)		2,699,624
		Auto Insurer in Mexico & Central America
				11,275,577
		> Guatemala 1.2%
	209,464	Tahoe Resources		2,099,881
		Silver & Gold Projects in Guatemala, Canada & Peru
Latin America: Total				13,375,458

Number of Shares			Value
Europe 7.0%
		> Finland 2.2%
	223,246	Tikkurila	$	4,054,344
		Decorative & Industrial Paint in Scandinavia, Central & Eastern Europe
		> Spain 1.3%
	414,753	Prosegur		2,336,139
		Security Guards
		> Kazakhstan 1.2%
	548,483	Halyk Savings Bank of Kazakhstan - GDR		2,303,629
		Retail Bank & Insurer in Kazakhstan
		> Sweden 1.2%
	41,183	Millicom International Cellular		2,250,842
		Telecoms Operator in Latin America & Africa
		> United Kingdom 1.1%
	369,998	PureCircle (a)(b)		2,015,370
		Natural Sweeteners
Europe: Total				12,960,324
Total Equities: 96.0% (Cost: $201,822,492)				176,716,402	(c)
Short-Term Investments 4.4%
	8,064,798	JPMorgan U.S. Government Money Market Fund, IM Shares (7 day yield of 0.25%)		8,064,798
Total Short-Term Investments: 4.4% (Cost: $8,064,798)				8,064,798
Securities Lending Collateral 0.3%
	495,986	Dreyfus Government Cash Management Fund, Institutional Shares (7 day yield of 0.20%) (d)		495,986
Total Securities Lending Collateral: 0.3% (Cost: $495,986)				495,986
Total Investments: 100.7% (Cost: $210,383,276)(e)				185,277,186	(f)
Obligation to Return Collateral for Securities Loaned: (0.3)%				(495,986	)
Cash and Other Assets Less Liabilities: (0.4)%				(820,998	)
Net Assets: 100.0%			$	183,960,202

ADR - American Depositary Receipts

GDR - Global Depositary Receipts

67

COLUMBIA ACORN EMERGING MARKETS FUND^SM

STATEMENT OF INVESTMENTS (UNAUDITED), CONTINUED

> Notes to Statement of Investments

(a)  Non-income producing security.

(b)  All or a portion of this security was on loan at March 31, 2016. The total market value of securities on loan at March 31, 2016 was $475,229.

(c)  On March 31, 2016, the Fund's total equity investments were denominated in currencies as follows:

Currency	Value		Percentage of Net Assets
Hong Kong Dollar	$	29,707,579		16.2
Taiwan Dollar		23,239,995		12.6
Korean Won		22,849,165		12.4
Indian Rupee		20,993,000		11.4
Indonesian Rupiah		14,949,211		8.1
U.S. Dollar		13,939,518		7.6
Other currencies less than 5% of total net assets		51,037,934		27.7
Total Equities	$	176,716,402		96.0

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

(e)  At March 31, 2016, for federal income tax purposes, the cost of investments was approximately $210,383,276 and net unrealized depreciation was $25,106,090 consisting of gross unrealized appreciation of $16,293,738 and gross unrealized depreciation of $41,399,828.

(f)  Securities are valued using policies described in the Notes to Financial Statements in the shareholder report dated December 31, 2015.

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.

68

> Notes to Statement of Investments

  The following table summarizes the inputs used, as of March 31, 2016, 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	$	4,440,996	$	130,531,312	$	-	$	134,972,308
Other Countries		5,281,258		10,127,054		-		15,408,312
Latin America		13,375,458		-		-		13,375,458
Europe		-		12,960,324		-		12,960,324
Total Equities		23,097,712		153,618,690		-		176,716,402
Total Short-Term Investments		8,064,798		-		-		8,064,798
Total Securities Lending Collateral		495,986		-		-		495,986
Total Investments	$	31,658,496	$	153,618,690	$	-	$	185,277,186

  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 following table reconciles asset balances for the period ending March 31, 2016, in which significant observable and/or unobservable inputs (Level 3) were used in determining value:

Investments in Securities	Balance as of December 31, 2015		Realized Gain (Loss)		Change in Unrealized Appreciation (Depreciation)		Purchases		Sales		Transfers Into Level 3		Transfers out of Level 3			Balance as of March 31, 2016
Equities
Asia	$	4,620,853	$	-	$	-	$	-	$	-	$	-	$	(4,620,853	)	$	-

  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.

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

  Transfers into 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 indices 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.

69

COLUMBIA ACORN EMERGING MARKETS FUND^SM

PORTFOLIO DIVERSIFICATION (UNAUDITED)

At March 31, 2016, the Fund's portfolio investments as a percentage of net assets were diversified as follows:

	Value		Percentage of Net Assets
> Information
Mobile Communications	$	9,859,159		5.4
Entertainment Programming		7,316,103		4.0
Semiconductors & Related Equipment		7,224,251		3.9
Internet Related		5,935,304		3.2
Cable TV		5,062,959		2.8
Satellite Broadcasting & Services		4,945,025		2.7
Instrumentation		4,515,584		2.5
Telephone & Data Services		2,250,842		1.2
Computer Hardware & Related Equipment		2,160,379		1.2
Telecommunications Equipment		2,092,746		1.1
Business Software		2,090,280		1.1
		53,452,632		29.1
> Consumer Goods & Services
Food & Beverage		12,274,288		6.7
Retail		9,806,782		5.3
Travel		9,315,455		5.1
Casinos & Gaming		6,116,309		3.3
Other Durable Goods		4,603,643		2.5
Restaurants		999,407		0.5
		43,115,884		23.4
> Industrial Goods & Services
Industrial Materials & Specialty Chemicals		9,694,710		5.3
Conglomerates		5,629,082		3.1
Water		4,833,951		2.6
Other Industrial Services		3,691,049		2.0
Outsourcing Services		2,336,139		1.3
Waste Management		2,303,814		1.2
		28,488,745		15.5
> Finance
Banks		9,084,072		4.9
Insurance		5,445,011		3.0
Brokerage & Money Management		4,880,334		2.6
Diversified Finance Companies		3,677,328		2.0
		23,086,745		12.5
> Health Care
Medical Supplies		5,267,118		2.9
Pharmaceuticals		4,120,995		2.2
Medical Equipment & Devices		1,345,717		0.7
		10,733,830		5.8

	Value			Percentage of Net Assets
> Other Industries
Transportation	$	8,937,408			4.9
		8,937,408			4.9
> Energy & Minerals
Oil Refining, Marketing & Distribution		4,390,767			2.4
Oil & Gas Producers		2,410,510			1.3
Mining		2,099,881			1.1
		8,901,158			4.8
Total Equities:		176,716,402			96.0
Short-Term Investments:		8,064,798			4.4
Securities Lending Collateral:		495,986			0.3
Total Investments:		185,277,186			100.7
Obligation to Return Collateral for Securities Loaned:		(495,986	)		(0.3	)
Cash and Other Assets Less Liabilities:		(820,998	)		(0.4	)
Net Assets:	$	183,960,202			100.0

70

COLUMBIA ACORN EUROPEAN FUND^SM

MAJOR PORTFOLIO CHANGES IN THE FIRST QUARTER (UNAUDITED)

	Number of Shares
	12/31/15		3/31/16
Purchases
Europe
> United Kingdom
Abcam		67,407		70,147
Assura		1,990,765		2,916,395
Big Yellow		0		58,000
Connect Group		394,721		479,111
Croda International		0		23,000
Domino's Pizza UK & Ireland		84,890		91,690
DS Smith		109,910		126,890
Halfords		185,700		188,450
Halma		74,150		81,340
Ocado		119,040		177,950
Polypipe		125,770		137,840
Regus		251,610		310,760
Rightmove		32,046		36,126
Shaftesbury		0		99,283
Spirax Sarco		19,907		22,547
> Germany
Elringklinger		25,162		30,662
Fielmann		0		10,400
MTU Aero Engines		13,010		13,990
NORMA Group		23,410		26,280
Wirecard		39,070		45,000
> Sweden
Mekonomen		55,190		57,390
Sweco		68,336		75,336
Trelleborg		33,170		86,210
Unibet		131,288		149,698
> Finland
Konecranes		36,750		42,570
Sponda		159,730		178,320
Tikkurila		71,311		88,511
> France
AKKA Technologies		26,716		36,566
> Spain
Bolsas y Mercados Españoles		18,200		21,510
Prosegur		208,710		256,710
Viscofan		10,310		12,910
> Netherlands
Aalberts Industries		37,180		39,930
Brunel		35,351		46,101
Gemalto		12,660		14,660
> Denmark
SimCorp		28,400		33,280
William Demant Holding		13,240		14,360

	Number of Shares
	12/31/15		3/31/16
> Switzerland
Inficon		2,030		2,200
Panalpina Welttransport		5,680		6,360
> Italy
Brembo		0		1,008
Industria Macchine Automatiche		12,460		12,930
> Belgium
Melexis		0		12,000

71

COLUMBIA ACORN EUROPEAN FUND^SM

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

	Number of Shares
	12/31/15		3/31/16
Sales
Europe
> United Kingdom
Babcock International		75,760		0
Charles Taylor		405,508		0
Elementis		180,730		0
Fidessa Group		4,057		0
Jardine Lloyd Thompson Group		41,010		0
> Germany
Rational		1,460		1,260
> Sweden
Hexagon		25,723		0
Swedish Match		23,852		0
> France
Cegedim		18,400		0
> Spain
Distribuidora Internacional de Alimentación		317,850		238,830
> Netherlands
Arcadis		38,625		0
Core Labs		5,680		0
Vopak		14,550		0
> Switzerland
Partners Group		4,450		3,347
> Norway
Orkla		79,320		0
> Belgium
EVS Broadcast Equipment		19,695		0

72

COLUMBIA ACORN EUROPEAN FUND^SM

STATEMENT OF INVESTMENTS (UNAUDITED), MARCH 31, 2016

Number of Shares			Value
			Equities: 95.4%
Europe 95.4%
		> United Kingdom 29.7%
	2,916,395	Assura	$	2,224,184
		UK Primary Health Care Property Developer
	36,126	Rightmove		2,184,917
		Internet Real Estate Listings
	310,760	Regus		1,413,523
		Rental of Office Space in Full Service Business Center
	91,690	Domino's Pizza UK & Ireland		1,327,432
		Pizza Delivery in the UK, Ireland & Switzerland
	99,283	Shaftesbury		1,299,042
		London Prime Retail REIT
	22,547	Spirax Sarco		1,178,745
		Steam Systems for Manufacturing & Process Industries
	479,111	Connect Group		1,094,115
		Newspaper & Magazine Distributor
	188,450	Halfords		1,072,089
		UK Retailer of Leisure Goods & Auto Parts
	81,340	Halma		1,064,855
		Health & Safety Sensor Technology
	23,000	Croda International		1,003,895
		Oleochemicals & Industrial Chemicals
	36,820	WH Smith		961,407
		Newsprint, Books & General Stationery Retailer
	126,890	DS Smith		743,562
		Packaging
	177,950	Ocado (a)		741,439
		Online Grocery Retailer
	272,070	Rentokil Initial		690,864
		Pest Control, Washroom & Workwear Service Provider
	58,000	Big Yellow		645,178
		UK Self Storage
	137,840	Polypipe		631,929
		Manufacturer of Plastic Piping & Fittings
	70,147	Abcam		594,417
		Online Sales of Antibodies
	106,900	PureCircle (a)		582,282
		Natural Sweeteners
				19,453,875
		> Germany 13.0%
	45,000	Wirecard (b)		1,705,143
		Online Payment Processing & Risk Management
	27,360	Aurelius		1,665,612
		European Turnaround Investor
	26,280	NORMA Group		1,472,174
		Clamps for Automotive & Industrial Applications
	13,990	MTU Aero Engines		1,341,831
		Airplane Engine Components & Services

Number of Shares			Value
	30,662	Elringklinger	$	840,333
		Automobile Components
	10,400	Fielmann		789,338
		Retail Optician Chain
	1,260	Rational		673,434
		Commercial Ovens
				8,487,865
		> Sweden 11.7%
	86,210	Trelleborg		1,705,457
		Manufacturer of Sealing, Dampening & Protective Solutions for Industry
	149,698	Unibet		1,699,217
		European Online Gaming Operator
	86,220	Recipharm (b)		1,614,318
		Contract Development Manufacturing Organization
	57,390	Mekonomen		1,420,921
		Nordic Integrated Wholesaler/Retailer of Automotive Parts & Service
	75,336	Sweco		1,237,930
		Engineering Consultants
				7,677,843
		> Finland 8.7%
	88,511	Tikkurila		1,607,438
		Decorative & Industrial Paint in Scandinavia, Central & Eastern Europe
	139,522	Munksjo		1,547,930
	68,560	Munksjo (c)		766,399
		Specialty Paper Maker
	42,570	Konecranes		1,016,279
		Manufacture & Service of Industrial Cranes & Port Handling Equipment
	178,320	Sponda		750,768
		Office, Retail & Logistics Properties
				5,688,814
		> France 6.5%
	36,566	AKKA Technologies		1,148,393
		Engineering Consultancy
	46,450	Elior Group (b)		1,018,524
		Contract Caterer & Travel Concessionary
	24,890	Bonduelle		732,699
		Producer of Canned, Deep-frozen & Fresh Vegetables
	1,860	Eurofins Scientific		682,252
		Food, Pharmaceuticals & Materials Screening & Testing
	20,641	Eutelsat		666,807
		Fixed Satellite Services
				4,248,675
		> Spain 6.3%
	256,710	Prosegur		1,445,946
		Security Guards
	238,830	Distribuidora Internacional de Alimentación		1,240,877
		Discount Retailer in Spain & Latin America

73

COLUMBIA ACORN EUROPEAN FUND^SM

STATEMENT OF INVESTMENTS (UNAUDITED), CONTINUED

Number of Shares			Value
		> Spain—continued
	12,910	Viscofan	$	773,444
		Sausage Casings Maker
	21,510	Bolsas y Mercados Españoles		693,901
		Spanish Stock Markets
				4,154,168
		> Netherlands 5.3%
	39,930	Aalberts Industries		1,385,354
		Flow Control & Heat Treatment
	14,660	Gemalto		1,083,804
		Digital Security Solutions
	46,101	Brunel		970,741
		Temporary Specialist & Energy Staffing
				3,439,899
		> Denmark 4.5%
	33,280	SimCorp		1,535,805
		Software for Investment Managers
	14,360	William Demant Holding (a)		1,444,004
		Manufacture & Distribution of Hearing Aids & Diagnostic Equipment
				2,979,809
		> Switzerland 4.2%
	3,347	Partners Group		1,345,344
		Private Markets Asset Management
	2,200	Inficon		726,431
		Gas Detection Instruments
	6,360	Panalpina Welttransport		710,378
		Air & Sea Freight Forwarding
				2,782,153
		> Italy 2.3%
	12,930	Industria Macchine Automatiche		758,458
		Food & Drugs Packaging & Machinery
	241,730	Hera		722,319
		Northern Italian Utility
	1,008	Brembo		52,131
		Original Equipment, Racing & Aftermarket Brakes for the Automotive Industry
				1,532,908
		> Norway 2.2%
	148,775	Atea		1,420,381
		Nordic IT Hardware/Software Reseller & Integrator

Number of Shares			Value
		> Belgium 1.0%
	12,000	Melexis	$	652,699
		Analog & Custom IC Designer
Europe: Total				62,519,089
Total Equities: 95.4% (Cost: $56,567,041)				62,519,089	(d)
Short-Term Investments 6.2%
	4,057,454	JPMorgan U.S. Government Money Market Fund, IM Shares (7 day yield of 0.25%)		4,057,454
Total Short-Term Investments: 6.2% (Cost: $4,057,454)				4,057,454
Securities Lending Collateral 2.3%
	1,481,300	Dreyfus Government Cash Management Fund, Institutional Shares (7 day yield of 0.20%) (e)		1,481,300
Total Securities Lending Collateral: 2.3% (Cost: $1,481,300)				1,481,300
Total Investments: 103.9% (Cost: $62,105,795)(f)				68,057,843	(g)
Obligation to Return Collateral for Securities Loaned: (2.3)%				(1,481,300	)
Cash and Other Assets Less Liabilities: (1.6)%				(1,068,159	)
Net Assets: 100.0%			$	65,508,384

REIT - Real Estate Investment Trust

> Notes to Statement of Investments

(a)  Non-income producing security.

(b)  All or a portion of this security was on loan at March 31, 2016. The total market value of securities on loan at March 31, 2016 was $1,415,614.

(c)  Security is traded on a Swedish exchange.

74

> Notes to Statement of Investments

(d)  On March 31, 2016, the Fund's total equity investments were denominated in currencies as follows:

Currency	Value		Percentage of Net Assets
Euro	$	27,438,630		41.9
British Pound		19,453,875		29.7
Swedish Krona		8,444,242		12.8
Other currencies less than 5% of total net assets		7,182,342		11.0
Total Equities	$	62,519,089		95.4

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

(f)  At March 31, 2016, for federal income tax purposes, the cost of investments was approximately $62,105,795 and net unrealized appreciation was $5,952,048 consisting of gross unrealized appreciation of $7,629,889 and gross unrealized depreciation of $1,677,841.

(g)  Securities are valued using policies described in the Notes to Financial Statements in the shareholder report dated December 31, 2015.

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.

75

COLUMBIA ACORN EUROPEAN FUND^SM

STATEMENT OF INVESTMENTS (UNAUDITED), CONTINUED

> Notes to Statement of Investments

  The following table summarizes the inputs used, as of March 31, 2016, 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	$	-	$	62,519,089	$	-	$	62,519,089
Total Equities		-		62,519,089		-		62,519,089
Total Short-Term Investments		4,057,454		-		-		4,057,454
Total Securities Lending Collateral		1,481,300		-		-		1,481,300
Total Investments	$	5,538,754	$	62,519,089	$	-	$	68,057,843

  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 during the period.

76

COLUMBIA ACORN EUROPEAN FUND^SM

PORTFOLIO DIVERSIFICATION (UNAUDITED)

At March 31, 2016, the Fund's portfolio investments as a percentage of net assets were diversified as follows:

	Value		Percentage of Net Assets
> Industrial Goods & Services
Industrial Materials & Specialty Chemicals	$	7,471,451		11.4
Machinery		5,825,522		8.9
Outsourcing Services		5,669,468		8.6
Other Industrial Services		3,972,390		6.1
Conglomerates		3,050,966		4.6
Construction		631,929		1.0
		26,621,726		40.6
> Consumer Goods & Services
Retail		5,436,733		8.3
Restaurants		2,345,957		3.6
Food & Beverage		2,088,424		3.2
Consumer Goods Distribution		1,883,454		2.9
Casinos & Gaming		1,699,217		2.5
Other Durable Goods		52,131		0.1
		13,505,916		20.6
> Information
Internet Related		2,184,917		3.3
Financial Processors		1,705,143		2.6
Business Software		1,535,805		2.3
Computer Services		1,420,381		2.2
Computer Hardware & Related Equipment		1,083,804		1.7
Instrumentation		1,064,855		1.6
Satellite Broadcasting & Services		666,807		1.0
Semiconductors & Related Equipment		652,699		1.0
		10,314,411		15.7
> Other Industries
Real Estate		3,620,129		5.5
Transportation		743,562		1.2
Regulated Utilities		722,319		1.1
		5,086,010		7.8
> Health Care
Pharmaceuticals		1,614,318		2.5
Medical Equipment & Devices		1,444,004		2.2
Medical Supplies		594,417		0.9
		3,652,739		5.6

	Value			Percentage of Net Assets
> Finance
Brokerage & Money Management	$	1,345,344			2.0
Diversified Financial Companies		1,299,042			2.0
Financial Processors		693,901			1.1
		3,338,287			5.1
Total Equities:		62,519,089			95.4
Short-Term Investments:		4,057,454			6.2
Securities Lending Collateral:		1,481,300			2.3
Total Investments:		68,057,843			103.9
Obligation to Return Collateral for Securities Loaned:		(1,481,300	)		(2.3	)
Cash and Other Assets Less Liabilities:		(1,068,159	)		(1.6	)
Net Assets:	$	65,508,384			100.0

77

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78

COLUMBIA ACORN FAMILY OF FUNDS EXPENSE INFORMATION

as of 3/31/16

Columbia Acorn® Fund	Class A			Class B(a)			Class C			Class I			Class R			Class R4			Class R5			Class Y			Class Z
Management Fees		0.66	%		0.66	%		0.66	%		0.66	%					0.66	%		0.66	%		0.66	%		0.66	%
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	%		0.96	%		0.20	%		0.12	%					0.37	%		0.17	%		0.12	%		0.18	%
Net Expense Ratio		1.15	%		2.37	%		1.86	%		0.78	%					1.03	%		0.83	%		0.78	%		0.84	%
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		0.27	%		0.97	%		0.26	%		0.14	%		0.39	%		0.33	%		0.18	%		0.13	%		0.24	%
Net Expense Ratio		1.28	%		2.48	%		2.02	%		0.90	%		1.65	%		1.09	%		0.94	%		0.89	%		1.00	%
Columbia Acorn USA®
Management Fees		0.89	%		0.89	%		0.89	%		0.89	%					0.89	%		0.89	%		0.89	%		0.89	%
Distribution and Service (12b-1) Fees		0.25	%		0.75	%		1.00	%		0.00	%					0.00	%		0.00	%		0.00	%		0.00	%
Other Expenses		0.29	%		6.54	%		0.23	%		0.10	%					0.32	%		0.19	%		0.14	%		0.28	%
Net Expense Ratio		1.43	%		8.18	%		2.12	%		0.99	%					1.21	%		1.08	%		1.03	%		1.17	%
Columbia Acorn International SelectSM
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		0.47	%		0.51	%		0.49	%		0.23	%					0.45	%		0.34	%		0.28	%		0.41	%
Net Expense Ratio		1.66	%		2.20	%		2.43	%		1.17	%					1.39	%		1.28	%		1.22	%		1.35	%
Columbia Acorn SelectSM
Management Fees		0.65	%		0.65	%		0.65	%		0.65	%					0.65	%		0.65	%		0.65	%		0.65	%
Distribution and Service (12b-1) Fees		0.25	%		0.75	%		1.00	%		0.00	%					0.00	%		0.00	%		0.00	%		0.00	%
Other Expenses		0.30	%		0.70	%		0.28	%		0.17	%					0.32	%		0.22	%		0.17	%		0.27	%
Net Expense Ratio		1.20	%		2.10	%		1.93	%		0.82	%					0.97	%		0.87	%		0.82	%		0.92	%
Columbia Thermostat FundSM
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	%		0.14	%		0.09	%		0.15	%
Net Expense Ratio(b)		0.50	%		1.00	%		1.25	%								0.25	%		0.24	%		0.19	%		0.25	%
Columbia Acorn Emerging Markets FundSM
Management Fees		1.11	%					1.11	%		1.11	%					1.11	%		1.11	%		1.11	%		1.11	%
Distribution and Service (12b-1) Fees		0.25	%					1.00	%		0.00	%					0.00	%		0.00	%		0.00	%		0.00	%
Other Expenses		0.44	%					0.45	%		0.28	%					0.42	%		0.33	%		0.31	%		0.49	%
Net Expense Ratio		1.80	%					2.56	%		1.39	%					1.53	%		1.44	%		1.42	%		1.60	%
Columbia Acorn European FundSM
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	%		0.22	%					0.31	%		0.27	%					0.30	%
Net Expense Ratio		1.75	%					2.50	%		1.41	%					1.50	%		1.46	%					1.49	%

    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 three months ended March 31, 2016. 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) 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 Columbia Management Investment Services Corp., the Funds' transfer agent, 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. On March 18, 2016, the Funds' transfer agent terminated its voluntary undertaking with respect to Class B shares of the Fund. Through April 30, 2017, the Fund's transfer agent has contractually agreed to waive all transfer agency fees payable by Class B shares of Columbia Acorn International.

(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. As of April 26, 2016, only Columbia Acorn International continues to offer Class B shares.

(b)    Does not include estimated fees and expenses of 0.55% incurred by the Fund from the underlying portfolio funds in which it invests.

79

COLUMBIA ACORN FAMILY OF FUNDS

Trustees

Laura M. Born

Chair of the Board

David J. Rudis

Vice Chair of the Board

Maureen M. Culhane

P. Zachary Egan

Margaret M. Eisen

Thomas M. Goldstein

John C. Heaton

Steven N. Kaplan

Charles R. Phillips

Ralph Wanger (Trustee Emeritus)

Officers

P. Zachary Egan

President

Alan G. Berkshire

Vice President

Michael G. Clarke

Assistant Treasurer

William J. Doyle

Vice President

David L. Frank

Vice President

Paul B. Goucher

Assistant Secretary and Chief Legal Officer

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

Matthew A. Litfin

Vice President

Satoshi Matsunaga

Vice President

Thomas P. McGuire

Chief Compliance Officer

Charles P. McQuaid*

Vice President

Louis J. Mendes

Vice President

Christopher J. Olson

Vice President

Julian Quero

Assistant Treasurer

Martha A. Skinner

Assistant Treasurer

Matthew S. Szafranski

Vice President

Andreas Waldburg-Wolfegg

Vice President

Linda K. Roth-Wiszowaty

Secretary

*Charles P. McQuaid retired on April 29, 2016.

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.

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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

First Quarter Report, March 31, 2016
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.

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.

© 2016 Columbia Management Investment Advisers, LLC. All rights reserved.

800.345.6611 columbiathreadneedle.com/us

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