MFS SERIES TRUST III, 497, 1999-07-20

MFS SERIES TRUST III
497, 1999-07-20

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                            MFS(R) EQUITY INCOME FUND
                             MFS(R) HIGH INCOME FUND


                      Supplement to the Current Prospectus



         During the period  from  August 2, 1999,  through  September  30,  1999
(unless extended by MFS Fund  Distributors,  Inc. ("MFD")) (the "Sales Period"),
MFD will pay Everen Securities, Inc.100% of the applicable sales charge on sales
of Class A shares of the Fund sold by them during the Sales Period. In addition,
MFD will pay Everen Securities,  Inc. an additional commission equal to 0.50% of
the net asset value of all of the Class B shares of the Fund sold by them during
the Sales Period.



                 The date of this Supplement is August 2, 1999.