Supplement dated September 1, 2016
to the Prospectus and Summary Prospectus, each as
supplemented, of the following fund:
Fund
|
Prospectus and
Summary Prospectus Dated |
Columbia
Acorn Trust |
|
Columbia
Thermostat Fund |
5/1/2016
|
Christopher J. Olson, CFA, a
co-portfolio manager of Columbia Thermostat Fund (the "Fund") and Vice President of Columbia Acorn Trust, has announced his intention to retire from the industry and will step down from these roles effective December 31, 2016.
David L. Frank, current co-portfolio manager of Columbia Thermostat Fund, will continue as sole portfolio manager of the Fund after that date. Mr. Olson will begin transitioning portfolio management responsibilities immediately and will
remain available through the end of the year to ensure a smooth transition in management.
Shareholders should retain this Supplement for future
reference.