<PAGE>
MFS UNION STANDARD EQUITY FUND
A Series of
MFS UNION STANDARD TRUST
Supplement to the Current Prospectus
MAA Consulting Services, Inc. ("MAA") has agreed to assist MFS Fund
Distributors, Inc. ("MFD") in the distribution of shares of the Fund. In
consideration of such assistance, MFD will pay MAA a commission equal to 0.15%
per annum of the Fund's average daily net assets attributable to shares of the
Fund owned by shareholders which were introduced to MFD by MAA and which
promptly thereafter, and as a direct result of the introduction and efforts of
MAA, purchased shares of the Fund.
The date of this Supplement is March 1, 1997