<PAGE>
Janus Venture Fund
Supplement dated December 21, 2000
to Prospectus dated January 31, 2000, as
supplemented March 16, 2000
THIS INFORMATION SUPPLEMENTS THE FUND'S PROSPECTUS. THIS SUPPLEMENT, ANY
PREVIOUS SUPPLEMENT(S) AND THE PROSPECTUS TOGETHER CONSTITUTE A CURRENT
PROSPECTUS. TO REQUEST ANOTHER COPY OF THE PROSPECTUS, PLEASE CALL
1-800-525-3713.
The following information supplements the information under "Management of the
Fund -- Portfolio Managers":
Effective December 31, 2000, Jonathan D. Coleman will no longer be an Executive
Vice President or a Co-Manager of the Fund, and William H. Bales will become the
sole Portfolio Manager of the Fund. Mr. Bales' biographical information
currently appears in the Prospectus. Mr. Coleman will become an Assistant
Portfolio Manager of Janus Fund.
VENSUPP-12/21/00
