May 01, 2016

Supplement dated June 27, 2016

to the Prospectus, Summary Prospectus and Statement of Additional Information ("SAI") of the following Fund:

Fund	Prospectus, Summary Prospectus and SAI Dated
Columbia Acorn Trust
Columbia Acorn International SelectSM	5/1/2016

1. The table under the caption "Fees and Expenses of the Fund" in the "Summary of the Fund" section of the Prospectus and the Summary Prospectus is hereby superseded and replaced with the following:

Shareholder Fees (fees paid directly from your investment)
	Class A	Class C	Classes I, R4, R5, Y and Z
Maximum sales charge (load) imposed on purchases (as a % of offering price)	5.75%	None	None
Maximum deferred sales charge (load) imposed on redemptions (as a % of the lower of the original purchase price or current net asset value)	1.00% (a)	1.00% (b)	None

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)
	Class A	Class C	Class I	Class R4	Class R5	Class Y	Class Z
Management fees(c)	0.89%	0.89%	0.89%	0.89%	0.89%	0.89%	0.89%
Distribution and/or service (12b-1) fees	0.25%	1.00%	0.00%	0.00%	0.00%	0.00%	0.00%
Other expenses(d)	0.42%	0.42%	0.30%	0.42%	0.35%	0.30%	0.42%
Total annual Fund operating expenses	1.56%	2.31%	1.19%	1.31%	1.24%	1.19%	1.31%
Less: Fee waivers and/or expense reimbursements(e)	(0.16%)	(0.16%)	(0.17%)	(0.16%)	(0.17%)	(0.17%)	(0.16%)
Total annual Fund operating expenses after fee waivers and/or expense reimbursements	1.40%	2.15%	1.02%	1.15%	1.07%	1.02%	1.15%

(a)	This charge is imposed on certain investments of between $1 million and $50 million redeemed within 18 months after purchase, as follows: 1.00% if redeemed within 12 months after purchase, and 0.50% if redeemed more than 12, but less than 18, months after purchase, with certain limited exceptions.
(b)	This charge applies to redemptions within 12 months after purchase, with certain limited exceptions.
(c)	Management fees have been restated to reflect current fees based on current asset levels and the contractual agreement of Columbia Wanger Asset Management, LLC (the Investment Manager), effective July 1, 2016, to permanently reduce the investment advisory fee paid by the Fund by 0.05% at all net asset levels.
(d)	Other expenses have been restated and are based on estimated amounts for the Fund's current fiscal year, taking into consideration changes in the Fund's net assets and changes in the method of allocating transfer agent expenses among Class A, Class C, Class R4 and Class Z shares of the Fund.
(e)	Effective July 1, 2016, the Investment Manager has contractually agreed to indefinitely waive fees and reimburse certain expenses of the Fund so that 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) do not exceed the annual rates of 1.40% for Class A shares, 2.15% for Class C shares, 1.02% for Class I shares, 1.15% for Class R4 shares, 1.07% for Class R5 shares, 1.02% for Class Y shares and 1.15% for Class Z shares. This arrangement may only be modified or amended with approval from the Fund.
2.	The expense example table that appears under the caption "Fees and Expenses of the Fund – Example" in the "Summary of the Fund" section of the Prospectus and the Summary Prospectus is hereby superseded and replaced with the following:

	1 year	3 years	5 years	10 years
Class A (whether or not shares are redeemed)	$709	$993	$1,297	$2,158
Class C (assuming redemption of all shares at the end of the period)	$318	$673	$1,154	$2,483
Class C (assuming no redemption of shares)	$218	$673	$1,154	$2,483
Class I (whether or not shares are redeemed)	$104	$325	$ 563	$1,248
Class R4 (whether or not shares are redeemed)	$117	$365	$ 633	$1,398
Class R5 (whether or not shares are redeemed)	$109	$340	$ 590	$1,306
Class Y (whether or not shares are redeemed)	$121	$378	$ 654	$1,443
Class Z (whether or not shares are redeemed)	$117	$365	$ 633	$1,398