December 22, 1997
SUPPLEMENT TO THE PROSPECTUS OF:
PIONEER MID-CAP FUND
DATED JANUARY 28, 1997
Effective December 22, 1997, the Fund will implement certain changes in its
non-fundamental investment policies. The following information supplements the
corresponding sections in the Prospectus. Please consult the Prospectus for the
full text of the revised sections.
COVER PAGE
The first sentence of the second paragraph on the cover page is revised as
follows:
In seeking to achieve its investment objective, the Fund will invest at
least 65% of its total assets in common stocks and common stock equivalents
(such as convertible bonds and preferred stock) of companies considered to be
mid-capitalization companies ("Mid-Cap Companies"). Mid-Cap Companies include
companies with market capitalizations within the range of market capitalizations
reflected in Standard & Poor's MidCap 400 Index (the "Index"). As of
December 1997, the market capitalization range of companies comprising the Index
was $218 million to $11.79 billion. The average weighted market capitalization
of the securities held in the Fund's portfolio may range from $1 billion to
$5 billion.
III. INVESTMENT OBJECTIVE AND POLICIES
The first sentence of the third paragraph is replaced with the following:
Under normal circumstances, at least 65% of the Fund's total assets are
invested in common stocks of Mid-Cap Companies. Mid-Cap Companies include
companies with market capitalizations at the time of investment within the range
of market capitalizations reflected in the Index. As of December 1997, the
market capitalization range of companies comprising the Index was $218 million
to $11.79 billion. The average weighted market capitalization of the securities
held in the Fund's portfolio may range from $1 billion to $5 billion.
1297-4713
[copyright symbol] Pioneer Funds Distributor, Inc.
