<PAGE>
Janus Money Market Fund
Janus Government Money Market Fund
Janus Tax-Exempt Money Market Fund
Investor Shares
Supplement Dated July 28, 2000
to Statement of Additional Information Dated January 31, 2000
THIS INFORMATION SUPPLEMENTS THE FUNDS' STATEMENT OF ADDITIONAL INFORMATION
DATED JANUARY 31, 2000. THIS SUPPLEMENT AND THE STATEMENT OF ADDITIONAL
INFORMATION CONSTITUTE A CURRENT STATEMENT OF ADDITIONAL INFORMATION. TO REQUEST
ANOTHER COPY OF THE STATEMENT OF ADDITIONAL INFORMATION, PLEASE CALL
1-800-525-3713.
THE FOLLOWING REPLACES THE INFORMATION ABOUT JANUS CAPITAL'S OWNERSHIP UNDER THE
HEADING "INVESTMENT ADVISER AND ADMINISTRATOR":
Effective July 12, 2000, Janus Capital is owned in part by Stilwell Financial
Inc. ("Stilwell"), which owns approximately 81.5% of the outstanding voting
stock of Janus Capital. Stilwell is a publicly traded holding company with
principal operations in financial asset management businesses. Thomas H. Bailey,
President and Chairman of the Board of Janus Capital, owns approximately 12% of
Janus Capital's voting stock, and by agreement with Stilwell, selects a majority
of Janus Capital's Board, subject to the approval of Stilwell, which cannot be
unreasonably withheld.
