<PAGE>
PROSPECTUS SUPPLEMENT FILED PURSUANT TO RULES 424(b)(3) AND (c)
DATED JULY 18, 1997 (TO PROSPECTUS FILE NO. (333-22907)
DATED APRIL 9, 1997)
2,404,346 SHARES
QUICKTURN DESIGN SYSTEMS, INC.
COMMON STOCK
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This Prospectus Supplement amends and supplements the Prospectus dated April
9, 1997 (the "Prospectus") of Quickturn Design Systems, Inc. (the "Company")
included in the Company's Registration Statement (No. 333-22907) covering shares
of the Company's Common Stock which may be offered and sold from time to time by
the Selling Stockholders named in the Prospectus.
The "Selling Stockholders" section of the Prospectus is hereby modified to
include in the Selling Stockholder table shares that are beneficially owned by
each of the Selling Stockholders which have been held in escrow pursuant to an
escrow agreement between the Company and the Selling Stockholders, which shares
were released from escrow on July 17, 1997. The "Selling Stockholders" section
contained in this Prospectus Supplement incorporates such modifications, and
amends and restates in its entirety the "Selling Stockholders" section contained
in the Prospectus. This Prospectus Supplement should be read in conjunction with
the Prospectus, and this Prospectus Supplement is qualified by reference to the
Prospectus except to the extent that the information contained herein supersedes
the information contained in the Prospectus. Capitalized terms used in this
Prospectus Supplement and not otherwise defined herein have the meanings
specified in the Prospectus.
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THESE SECURITIES HAVE NOT BEEN APPROVED OR DISAPPROVED BY THE SECURITIES AND
EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION NOR HAS THE
SECURITIES AND EXCHANGE COMMISSION OR ANY STATE SECURITIES
COMMISSION PASSED UPON THE ACCURACY OR ADEQUACY OF
THIS PROSPECTUS. ANY REPRESENTATION TO THE
CONTRARY IS A CRIMINAL OFFENSE.
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SELLING STOCKHOLDERS
The following table sets forth as of the date of this Prospectus, the name
of each of the Selling Stockholders, the number of shares of Common Stock that
each such Selling Stockholder owns as of such date, the number of shares of
Common Stock owned by each Selling Stockholder that may be offered for sale from
time to time by this Prospectus, and the number of shares of Common Stock to be
held by each such Selling Stockholder assuming the sale of all the Common Stock
offered hereby. Except as indicated, none of the Selling Stockholders has held
any position or office or had a material relationship with the Company or any of
its affiliates within the past three years other than as a result of the
ownership of the Company's Common Stock. The Company may amend or supplement
this Prospectus from time to time to update the disclosure set forth herein.
<TABLE>
<CAPTION>
SHARES
BENEFICIALLY
OWNED
SHARES SHARES WHICH MAY AFTER OFFERING(2)
BENEFICIALLY BE SOLD PURSUANT TO -----------------
SELLING STOCKHOLDER OWNED(1) THIS PROSPECTUS NUMBER PERCENT
- --------------------------------------------- ------------ ------------------- ------- -------
<S> <C> <C> <C> <C>
Fidelity Investors Limited Partnership....... 796,142 796,142 0 --
John J. Shields.............................. 58,383(3) 58,383(5) 0 --
Judith A. Shields............................ 58,383(4) 58,383(5) 0 --
Donald J. McInnis(6)......................... 603,051 603,051 0 --
Kevin L. Ladd(7)............................. 603,051 603,051 0 --
Douglas B. Day............................... 94,847 94,847 0 --
Christopher Mega............................. 7,589 7,589 0 --
Keith A. Westgate............................ 86,195 86,195 0 --
Richard Sayde................................ 155,088 155,088 0 --
</TABLE>
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(1) The number and percentage of shares beneficially owned is determined in
accordance with Rule 13d-3 of the Exchange Act, and the information is not
necessarily indicative of beneficial ownership for any other purpose. Under
such rule, beneficial ownership includes any shares as to which the
individual has sole or shared voting power or investment power and also any
shares which the individual has the right to acquire within 60 days of the
date of this Prospectus through the exercise of any stock option or other
right. Unless otherwise indicated in the footnotes, each person has sole
voting and investment power (or shares such powers with his or her spouse)
with respect to the shares shown as beneficially owned.
(2) Assumes the sale of all Common Stock offered hereby.
(3) Includes 53,076 shares of Common Stock held of record by Judith A. Shields,
Mr. Shields' spouse.
(4) Includes 5,307 shares of Common Stock held of record by John J. Shields, Ms.
Shields' spouse.
(5) Includes shares of Common Stock held of record by each of Mr. and Ms.
Shields.
(6) Mr. McInnis is Senior Vice President, Advanced Simulation Division of the
Company.
(7) Mr. Ladd is Vice President and Chief Technologist, Advanced Simulation
Division of the Company.
2
