<PAGE>
MFS(R) EMERGING GROWTH FUND
Supplement to the Current Prospectus
The description of portfolio managers under the "Management of the Funds"
section is hereby restated as follows:
John W. Ballen, President and Chief Investment Officer of MFS, has been employed
by MFS as a portfolio manager since 1984. Mr. Ballen has been the fund's
portfolio manager since the fund's inception in 1986. Dale A. Dutile, a Vice
President of MFS, has been employed by MFS as a portfolio manager since 1994.
Mr. Dutile became a portfolio manager of the fund on February 1, 2000.
The date of this Supplement is February 1, 2000.
