<PAGE>
MFS RESEARCH FUND
Supplement to the February 1, 1995 Prospectus and Statement of Additional
Information
The section of the Prospectus entitled "Expense Summary" is hereby revised as
follows:
1. EXPENSE SUMMARY
Shareholder Transaction Expenses: Class A Class B Class C
Maximum Initial Sales Charge Imposed
on Purchases of Fund Shares (as a
percentage of offering price)............... 5.75% 0.00% 0.00%
Maximum Contingent Deferred Sales
Charge (as a percentage of original
purchase price or redemption proceeds,
as applicable).............................. See Below1 4.00% 0.00%
Annual Operating Expenses of the Fund (as a percentage of average daily net
assets):
Management Fees.............................. 0.39% 0.39% 0.39%
Rule 12b-1 Fees.............................. 0.30%2 1.00%3 1.00%3
Other Expenses............................... 0.32% 0.43% 0.35%
Total Operating Expenses..................... 1.01% 1.82% 1.74%
- -----------------------------
1. Purchases of $1 million or more are not subject to an initial sales charge;
however, a contingent deferred sales charge ("CDSC") of 1% will be imposed on
such purchases in the event of certain redemption transactions within 12 months
following such purchases (see "Purchases").
2. The Fund has adopted a Distribution Plan for its Class A shares in accordance
with Rule 12b-1 under the Investment Company Act of 1940, as amended (the "1940
Act"), which provides that it will pay distribution/service fees aggregating up
to (but not necessarily all of) 0.35% per annum of the average daily net assets
attributable to Class A shares (see "Distribution Plans"). The 0.25% per annum
service fee is reduced to 0.15% per annum for shares purchased prior to March 1,
1991. Distribution expenses paid under this Plan, together with the initial
sales charge, may cause long-term shareholders to pay more than the maximum
sales charge that would have been permissible if imposed entirely as an initial
sales charge.
3. The Fund has adopted separate Distribution Plans for its Class B and its
Class C shares in accordance with Rule 12b-1 under the 1940 Act, which provides
that it will pay distribution/service fees aggregating up to 1.00% per annum of
the average daily net assets attributable to Class B shares under the Class B
Distribution Plan and the Class C shares under the Class C Distribution Plan
(see "Distribution Plans"). Distribution expenses paid under these Plans,
together with any CDSC payable upon redemption of Class B shares, may cause
long-term shareholders to pay more than the maximum sales charge that would have
been permissible if imposed entirely as an initial sales charge.
Example of Expenses
An investor would pay the following dollar amounts of expenses on a $1,000
investment in the Fund, assuming (a) a 5% annual return and (b) redemption at
the end of each of the time periods indicated (unless otherwise noted):
Period
Class A Class B Class C
(1)
1 year.............................. $ 67 $ 58 $ 18 $ 18
3 years............................. 88 87 57 55
5 years............................. 110 119 99 94
10 years............................. 174 192(2) 192(2) 205
- -----------------------------
1. Assumes no redemption.
2. Class B shares convert to Class A shares approximately eight years after
purchase; therefore, years nine and ten reflect Class A expenses.
The purpose of the expense table above is to assist investors in understanding
the various costs and expenses that a shareholder of the Fund will bear directly
or indirectly. More complete descriptions of the following Fund expenses are set
forth in the following sections: (i) varying sales charges on share purchases -
"Purchases"; (ii) varying CDSCs "Purchases"; (iii) management fees - "Investment
Adviser"; and (iv) Rule 12b-1 (i.e., distribution plan) fees - "Distribution
Plans."
The "Example" set forth above should not be considered a representation of past
or future expenses of the Fund; actual expenses may be greater or less than
those shown.
* * *
Page 18 of the Prospectus and page 14 of the Statement of Additional Information
are each revised to delete the sentence stating that MFS Fund Distributors, Inc.
is currently suspending its receipt of the 0.10% per annum distribution fee with
respect to Class A shares.
The date of this Supplement is January 1, 1996.