BARON

FUNDS^®

Baron Durable Advantage Fund

Supplement dated June 7, 2018

to Summary Prospectus dated January 26, 2018

IMPORTANT NOTICE REGARDING CHANGE IN THE INVESTMENT STRATEGY

Effective Monday, August 6, 2018, in connection with the principal investment strategy of Baron Durable Advantage Fund (the “Fund”), the Summary Prospectus of the Fund is modified as follows:

On page 2 of the Summary Prospectus, the following sentence under “Principal Investment Strategies of the Fund,” which reads as follows: “The Adviser defines large-sized companies as those, at the time of purchase, with market capitalizations above the smallest market cap stock in the top 85% of the Russell 1000 Growth Index at reconstitution, or companies with market capitalizations above $10 billion, whichever is smaller.” is deleted in its entirety and replaced with the following: “The Adviser defines large-sized companies as those, at the time of purchase, with market capitalizations no smaller than the top 90^th percentile by total market capitalization of the S&P 500 Index at June 30, or companies with market capitalizations above $10 billion, whichever is smaller.”

This information supplements the Summary Prospectus dated January 26, 2018. This Supplement and the Summary Prospectus constitute a current prospectus. To request another copy of the Summary Prospectus or the Prospectus, please call 1-800-992-2766 or visit our website at www.BaronFunds.com.