SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K/A CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): December 8, 1998 ------------------------------ QUICKTURN DESIGN SYSTEMS, INC. - -------------------------------------------------------------------------------- (Exact name of registrant as specified in its charter) Delaware 0-22738 77-0159619 - -------------------------------------------------------------------------------- (State or other (Commission (IRS Employer jurisdiction of File Number) Identification Number) incorporation) 55 W. TRIMBLE ROAD SAN JOSE, CA 95131 - -------------------------------------------------------------------------------- (Address of principal executive offices) (Zip Code) Registrant's telephone number, including area code: (408) 914-6000 ---------------------- N/A - -------------------------------------------------------------------------------- (Former name or former address, if changed since last report) ITEM 5. OTHER EVENTS.. ------------- On January 4, 1999, Quickturn Design Systems, Inc. ("Quickturn") and Cadence Design Systems, Inc. ("Cadence") amended their Agreement and Plan of Merger (the "Merger Agreement") dated as of December 8, 1998, as amended on December 16, 1998, to reflect an increase in the value of the shares of common stock of Cadence to be received in connection with the merger by holders of common stock of Quickturn to $15.00 per share of Quickturn common stock. ITEM 7. FINANCIAL STATEMENTS AND EXHIBITS. --------------------------------- (c) Exhibits -------- 2.1 Amendment No. 2 dated as of January 4, 1999 to Agreement and Plan of Merger, dated as of December 8, 1998, by and among the Registrant, CDSI Acquisition, Inc. and Quickturn Design Systems, Inc. -2- SIGNATURES Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this Report to be signed on its behalf by the undersigned hereunto duly authorized. Dated: January 6,1999 QUICKTURN DESIGN SYSTEMS, INC. /s/ RAYMOND K. OSTBY ---------------------------------------- Raymond K. Ostby Vice President, Finance and Administration, Chief Financial Officer and Secretary -3- INDEX TO EXHIBITS ----------------- Exhibit Number Description of Document ------ ----------------------- 2.1 Amendment No. 2 dated as of January 4, 1999 to Agreement and Plan of Merger, dated as of December 8, 1998, by and among the Registrant, CDSI Acquisition, Inc. and Quickturn Design Systems, Inc.