<SEC-DOCUMENT>0001193125-19-066618-index.html : 20190307
<SEC-HEADER>0001193125-19-066618.hdr.sgml : 20190307
<ACCEPTANCE-DATETIME>20190307094647
ACCESSION NUMBER:		0001193125-19-066618
CONFORMED SUBMISSION TYPE:	N-CSR
PUBLIC DOCUMENT COUNT:		28
CONFORMED PERIOD OF REPORT:	20181231
FILED AS OF DATE:		20190307
DATE AS OF CHANGE:		20190307
EFFECTIVENESS DATE:		20190307

FILER:

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			COLUMBIA ACORN TRUST
		CENTRAL INDEX KEY:			0000002110
		IRS NUMBER:				362692100
		STATE OF INCORPORATION:			MA
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		N-CSR
		SEC ACT:		1940 Act
		SEC FILE NUMBER:	811-01829
		FILM NUMBER:		19664544

	BUSINESS ADDRESS:	
		STREET 1:		227 W MONROE STE 3000
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60606
		BUSINESS PHONE:		3126349200

	MAIL ADDRESS:	
		STREET 1:		227 W MONROE STE 3000
		CITY:			CHICAGO
		STATE:			IL
		ZIP:			60606

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	LIBERTY ACORN TRUST
		DATE OF NAME CHANGE:	20010424

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	ACORN INVESTMENT TRUST
		DATE OF NAME CHANGE:	19940204

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	ACORN FUND INC
		DATE OF NAME CHANGE:	19920703
<SERIES-AND-CLASSES-CONTRACTS-DATA>
<EXISTING-SERIES-AND-CLASSES-CONTRACTS>
<SERIES>
<OWNER-CIK>0000002110
<SERIES-ID>S000009184
<SERIES-NAME>Columbia Acorn Fund
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000024954
<CLASS-CONTRACT-NAME>Columbia Acorn Fund Class A
<CLASS-CONTRACT-TICKER-SYMBOL>LACAX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000024956
<CLASS-CONTRACT-NAME>Columbia Acorn Fund Class C
<CLASS-CONTRACT-TICKER-SYMBOL>LIACX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000024957
<CLASS-CONTRACT-NAME>Columbia Acorn Fund Institutional Class
<CLASS-CONTRACT-TICKER-SYMBOL>ACRNX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000122735
<CLASS-CONTRACT-NAME>Columbia Acorn Fund Advisor Class
<CLASS-CONTRACT-TICKER-SYMBOL>CEARX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000122736
<CLASS-CONTRACT-NAME>Columbia Acorn Fund Institutional 2 Class
<CLASS-CONTRACT-TICKER-SYMBOL>CRBRX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000122737
<CLASS-CONTRACT-NAME>Columbia Acorn Fund Institutional 3 Class
<CLASS-CONTRACT-TICKER-SYMBOL>CRBYX
</CLASS-CONTRACT>
</SERIES>
<SERIES>
<OWNER-CIK>0000002110
<SERIES-ID>S000009185
<SERIES-NAME>Columbia Acorn International
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000024958
<CLASS-CONTRACT-NAME>Columbia Acorn International Class A
<CLASS-CONTRACT-TICKER-SYMBOL>LAIAX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000024960
<CLASS-CONTRACT-NAME>Columbia Acorn International Class C
<CLASS-CONTRACT-TICKER-SYMBOL>LAICX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000024961
<CLASS-CONTRACT-NAME>Columbia Acorn International Institutional Class
<CLASS-CONTRACT-TICKER-SYMBOL>ACINX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000097732
<CLASS-CONTRACT-NAME>Columbia Acorn International Class R
<CLASS-CONTRACT-TICKER-SYMBOL>CACRX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000097733
<CLASS-CONTRACT-NAME>Columbia Acorn International Institutional 2 Class
<CLASS-CONTRACT-TICKER-SYMBOL>CAIRX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000122738
<CLASS-CONTRACT-NAME>Columbia Acorn International Advisor Class
<CLASS-CONTRACT-TICKER-SYMBOL>CCIRX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000122739
<CLASS-CONTRACT-NAME>Columbia Acorn International Institutional 3 Class
<CLASS-CONTRACT-TICKER-SYMBOL>CCYIX
</CLASS-CONTRACT>
</SERIES>
<SERIES>
<OWNER-CIK>0000002110
<SERIES-ID>S000009186
<SERIES-NAME>Columbia Acorn USA
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000024962
<CLASS-CONTRACT-NAME>Columbia Acorn USA Class A
<CLASS-CONTRACT-TICKER-SYMBOL>LAUAX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000024964
<CLASS-CONTRACT-NAME>Columbia Acorn USA Class C
<CLASS-CONTRACT-TICKER-SYMBOL>LAUCX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000024965
<CLASS-CONTRACT-NAME>Columbia Acorn USA Institutional Class
<CLASS-CONTRACT-TICKER-SYMBOL>AUSAX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000122740
<CLASS-CONTRACT-NAME>Columbia Acorn USA Advisor Class
<CLASS-CONTRACT-TICKER-SYMBOL>CUSAX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000122741
<CLASS-CONTRACT-NAME>Columbia Acorn USA Institutional 2 Class
<CLASS-CONTRACT-TICKER-SYMBOL>CYSRX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000122742
<CLASS-CONTRACT-NAME>Columbia Acorn USA Institutional 3 Class
<CLASS-CONTRACT-TICKER-SYMBOL>CUSYX
</CLASS-CONTRACT>
</SERIES>
<SERIES>
<OWNER-CIK>0000002110
<SERIES-ID>S000009187
<SERIES-NAME>Columbia Acorn Select
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000024966
<CLASS-CONTRACT-NAME>Columbia Acorn Select Class A
<CLASS-CONTRACT-TICKER-SYMBOL>LTFAX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000024968
<CLASS-CONTRACT-NAME>Columbia Acorn Select Class C
<CLASS-CONTRACT-TICKER-SYMBOL>LTFCX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000024969
<CLASS-CONTRACT-NAME>Columbia Acorn Select Institutional Class
<CLASS-CONTRACT-TICKER-SYMBOL>ACTWX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000122743
<CLASS-CONTRACT-NAME>Columbia Acorn Select Advisor Class
<CLASS-CONTRACT-TICKER-SYMBOL>CSSRX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000122744
<CLASS-CONTRACT-NAME>Columbia Acorn Select Institutional 2 Class
<CLASS-CONTRACT-TICKER-SYMBOL>CSLRX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000122745
<CLASS-CONTRACT-NAME>Columbia Acorn Select Institutional 3 Class
<CLASS-CONTRACT-TICKER-SYMBOL>CSLYX
</CLASS-CONTRACT>
</SERIES>
<SERIES>
<OWNER-CIK>0000002110
<SERIES-ID>S000009188
<SERIES-NAME>Columbia Acorn International Select
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000024970
<CLASS-CONTRACT-NAME>Columbia Acorn International Select Class A
<CLASS-CONTRACT-TICKER-SYMBOL>LAFAX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000024972
<CLASS-CONTRACT-NAME>Columbia Acorn International Select Class C
<CLASS-CONTRACT-TICKER-SYMBOL>LFFCX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000024973
<CLASS-CONTRACT-NAME>Columbia Acorn International Select Institutional Class
<CLASS-CONTRACT-TICKER-SYMBOL>ACFFX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000122746
<CLASS-CONTRACT-NAME>Columbia Acorn International Select Institutional 2 Class
<CLASS-CONTRACT-TICKER-SYMBOL>CRIRX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000122747
<CLASS-CONTRACT-NAME>Columbia Acorn International Select Institutional 3 Class
<CLASS-CONTRACT-TICKER-SYMBOL>CSIRX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000122748
<CLASS-CONTRACT-NAME>Columbia Acorn International Select Advisor Class
<CLASS-CONTRACT-TICKER-SYMBOL>CILRX
</CLASS-CONTRACT>
</SERIES>
<SERIES>
<OWNER-CIK>0000002110
<SERIES-ID>S000009189
<SERIES-NAME>Columbia Thermostat Fund
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000024974
<CLASS-CONTRACT-NAME>Columbia Thermostat Fund Class A
<CLASS-CONTRACT-TICKER-SYMBOL>CTFAX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000024976
<CLASS-CONTRACT-NAME>Columbia Thermostat Fund Class C
<CLASS-CONTRACT-TICKER-SYMBOL>CTFDX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000024977
<CLASS-CONTRACT-NAME>Columbia Thermostat Fund Institutional Class
<CLASS-CONTRACT-TICKER-SYMBOL>COTZX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000122749
<CLASS-CONTRACT-NAME>Columbia Thermostat Fund Advisor Class
<CLASS-CONTRACT-TICKER-SYMBOL>CTORX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000122750
<CLASS-CONTRACT-NAME>Columbia Thermostat Fund Institutional 2 Class
<CLASS-CONTRACT-TICKER-SYMBOL>CQTRX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000122751
<CLASS-CONTRACT-NAME>Columbia Thermostat Fund Institutional 3 Class
<CLASS-CONTRACT-TICKER-SYMBOL>CYYYX
</CLASS-CONTRACT>
</SERIES>
<SERIES>
<OWNER-CIK>0000002110
<SERIES-ID>S000033621
<SERIES-NAME>Columbia Acorn European Fund
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000103324
<CLASS-CONTRACT-NAME>Columbia Acorn European Fund Class A
<CLASS-CONTRACT-TICKER-SYMBOL>CAEAX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000103325
<CLASS-CONTRACT-NAME>Columbia Acorn European Fund Class C
<CLASS-CONTRACT-TICKER-SYMBOL>CAECX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000103327
<CLASS-CONTRACT-NAME>Columbia Acorn European Fund Institutional Class
<CLASS-CONTRACT-TICKER-SYMBOL>CAEZX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000122752
<CLASS-CONTRACT-NAME>Columbia Acorn European Fund Institutional 2 Class
<CLASS-CONTRACT-TICKER-SYMBOL>CAEEX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000144049
<CLASS-CONTRACT-NAME>Columbia Acorn European Fund Advisor Class
<CLASS-CONTRACT-TICKER-SYMBOL>CLOFX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000171393
<CLASS-CONTRACT-NAME>Columbia Acorn European Fund Institutional 3 Class
<CLASS-CONTRACT-TICKER-SYMBOL>CAEYX
</CLASS-CONTRACT>
</SERIES>
<SERIES>
<OWNER-CIK>0000002110
<SERIES-ID>S000033622
<SERIES-NAME>Columbia Acorn Emerging Markets Fund
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000103328
<CLASS-CONTRACT-NAME>Columbia Acorn Emerging Markets Fund Class A
<CLASS-CONTRACT-TICKER-SYMBOL>CAGAX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000103329
<CLASS-CONTRACT-NAME>Columbia Acorn Emerging Markets Fund Class C
<CLASS-CONTRACT-TICKER-SYMBOL>CGMCX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000103331
<CLASS-CONTRACT-NAME>Columbia Acorn Emerging Markets Fund Institutional Class
<CLASS-CONTRACT-TICKER-SYMBOL>CEFZX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000122753
<CLASS-CONTRACT-NAME>Columbia Acorn Emerging Markets Fund Advisor Class
<CLASS-CONTRACT-TICKER-SYMBOL>CAERX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000122754
<CLASS-CONTRACT-NAME>Columbia Acorn Emerging Markets Fund Institutional 2 Class
<CLASS-CONTRACT-TICKER-SYMBOL>CANRX
</CLASS-CONTRACT>
<CLASS-CONTRACT>
<CLASS-CONTRACT-ID>C000128887
<CLASS-CONTRACT-NAME>Columbia Acorn Emerging Markets Fund Institutional 3 Class
<CLASS-CONTRACT-TICKER-SYMBOL>CPHRX
</CLASS-CONTRACT>
</SERIES>
</EXISTING-SERIES-AND-CLASSES-CONTRACTS>
</SERIES-AND-CLASSES-CONTRACTS-DATA>
</SEC-HEADER>
<DOCUMENT>
<TYPE>N-CSR
<SEQUENCE>1
<FILENAME>d688177dncsr.htm
<DESCRIPTION>COLUMBIA ACORN TRUST
<TEXT>
Document 1 - file: d688177dncsr.htm
</DOCUMENT> <DOCUMENT> <TYPE>EX-99.CODE ETH <SEQUENCE>2 <FILENAME>d688177dex99codeeth.htm <DESCRIPTION>CODE OF ETHICS <TEXT> Document 2 - file: d688177dex99codeeth.htm
</DOCUMENT> <DOCUMENT> <TYPE>EX-99.CERT <SEQUENCE>3 <FILENAME>d688177dex99cert.htm <DESCRIPTION>SECTION 302 CERTIFICATION <TEXT> Document 3 - file: d688177dex99cert.htm
</DOCUMENT> <DOCUMENT> <TYPE>EX-99.906CERT <SEQUENCE>4 <FILENAME>d688177dex99906cert.htm <DESCRIPTION>SECTION 906 CERTIFICATION <TEXT> Document 4 - file: d688177dex99906cert.htm
</DOCUMENT> <DOCUMENT> <TYPE>GRAPHIC <SEQUENCE>5 <FILENAME>g688177img1f1d062b8.jpg <DESCRIPTION>GRAPHIC <TEXT> Document 5 - file: g688177img1f1d062b8.jpg
</DOCUMENT> <DOCUMENT> <TYPE>GRAPHIC <SEQUENCE>6 <FILENAME>g688177img24a7a1f76.jpg <DESCRIPTION>GRAPHIC <TEXT> Document 6 - file: g688177img24a7a1f76.jpg
</DOCUMENT> <DOCUMENT> <TYPE>GRAPHIC <SEQUENCE>7 <FILENAME>g688177img2b8a417f4.jpg <DESCRIPTION>GRAPHIC <TEXT> Document 7 - file: g688177img2b8a417f4.jpg
</DOCUMENT> <DOCUMENT> <TYPE>GRAPHIC <SEQUENCE>8 <FILENAME>g688177img2cf348601.jpg <DESCRIPTION>GRAPHIC <TEXT> Document 8 - file: g688177img2cf348601.jpg
</DOCUMENT> <DOCUMENT> <TYPE>GRAPHIC <SEQUENCE>9 <FILENAME>g688177img2d246b1823.jpg <DESCRIPTION>GRAPHIC <TEXT> Document 9 - file: g688177img2d246b1823.jpg
</DOCUMENT> <DOCUMENT> <TYPE>GRAPHIC <SEQUENCE>10 <FILENAME>g688177img333a396a12.jpg <DESCRIPTION>GRAPHIC <TEXT> Document 10 - file: g688177img333a396a12.jpg
</DOCUMENT> <DOCUMENT> <TYPE>GRAPHIC <SEQUENCE>11 <FILENAME>g688177img424ad7c47.jpg <DESCRIPTION>GRAPHIC <TEXT> Document 11 - file: g688177img424ad7c47.jpg
</DOCUMENT> <DOCUMENT> <TYPE>GRAPHIC <SEQUENCE>12 <FILENAME>g688177img437913ae17.jpg <DESCRIPTION>GRAPHIC <TEXT> Document 12 - file: g688177img437913ae17.jpg
</DOCUMENT> <DOCUMENT> <TYPE>GRAPHIC <SEQUENCE>13 <FILENAME>g688177img43886a2920.jpg <DESCRIPTION>GRAPHIC <TEXT> Document 13 - file: g688177img43886a2920.jpg
</DOCUMENT> <DOCUMENT> <TYPE>GRAPHIC <SEQUENCE>14 <FILENAME>g688177img447a64403.jpg <DESCRIPTION>GRAPHIC <TEXT> Document 14 - file: g688177img447a64403.jpg
</DOCUMENT> <DOCUMENT> <TYPE>GRAPHIC <SEQUENCE>15 <FILENAME>g688177img7f7ac52416.jpg <DESCRIPTION>GRAPHIC <TEXT> Document 15 - file: g688177img7f7ac52416.jpg
</DOCUMENT> <DOCUMENT> <TYPE>GRAPHIC <SEQUENCE>16 <FILENAME>g688177img9039bb3f9.jpg <DESCRIPTION>GRAPHIC <TEXT> Document 16 - file: g688177img9039bb3f9.jpg
</DOCUMENT> <DOCUMENT> <TYPE>GRAPHIC <SEQUENCE>17 <FILENAME>g688177img9a0a354e10.jpg <DESCRIPTION>GRAPHIC <TEXT> Document 17 - file: g688177img9a0a354e10.jpg
</DOCUMENT> <DOCUMENT> <TYPE>GRAPHIC <SEQUENCE>18 <FILENAME>g688177imga91c747f5.jpg <DESCRIPTION>GRAPHIC <TEXT> Document 18 - file: g688177imga91c747f5.jpg
</DOCUMENT> <DOCUMENT> <TYPE>GRAPHIC <SEQUENCE>19 <FILENAME>g688177imgae7f191818.jpg <DESCRIPTION>GRAPHIC <TEXT> Document 19 - file: g688177imgae7f191818.jpg
</DOCUMENT> <DOCUMENT> <TYPE>GRAPHIC <SEQUENCE>20 <FILENAME>g688177imgb9e4b1f221.jpg <DESCRIPTION>GRAPHIC <TEXT> Document 20 - file: g688177imgb9e4b1f221.jpg
</DOCUMENT> <DOCUMENT> <TYPE>GRAPHIC <SEQUENCE>21 <FILENAME>g688177imgc5c2c31b22.jpg <DESCRIPTION>GRAPHIC <TEXT> Document 21 - file: g688177imgc5c2c31b22.jpg
</DOCUMENT> <DOCUMENT> <TYPE>GRAPHIC <SEQUENCE>22 <FILENAME>g688177imgd2857eb115.jpg <DESCRIPTION>GRAPHIC <TEXT> Document 22 - file: g688177imgd2857eb115.jpg
</DOCUMENT> <DOCUMENT> <TYPE>GRAPHIC <SEQUENCE>23 <FILENAME>g688177imgd680653b13.jpg <DESCRIPTION>GRAPHIC <TEXT> Document 23 - file: g688177imgd680653b13.jpg
</DOCUMENT> <DOCUMENT> <TYPE>GRAPHIC <SEQUENCE>24 <FILENAME>g688177imge881052514.jpg <DESCRIPTION>GRAPHIC <TEXT> Document 24 - file: g688177imge881052514.jpg
</DOCUMENT> <DOCUMENT> <TYPE>GRAPHIC <SEQUENCE>25 <FILENAME>g688177imgea4cb2872.jpg <DESCRIPTION>GRAPHIC <TEXT> Document 25 - file: g688177imgea4cb2872.jpg
</DOCUMENT> <DOCUMENT> <TYPE>GRAPHIC <SEQUENCE>26 <FILENAME>g688177imged211d8711.jpg <DESCRIPTION>GRAPHIC <TEXT> Document 26 - file: g688177imged211d8711.jpg
</DOCUMENT> <DOCUMENT> <TYPE>GRAPHIC <SEQUENCE>27 <FILENAME>g688177imgfd972e9e19.jpg <DESCRIPTION>GRAPHIC <TEXT> Document 27 - file: g688177imgfd972e9e19.jpg
</DOCUMENT> <DOCUMENT> <TYPE>GRAPHIC <SEQUENCE>28 <FILENAME>g688177imgfef90e3524.jpg <DESCRIPTION>GRAPHIC <TEXT> Document 28 - file: g688177imgfef90e3524.jpg
</DOCUMENT> </SEC-DOCUMENT>