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 jurisdiction (Commission (IRS Employer of incorporation) File Number) Identification Number) 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 December 16, 1998, Quickturn Design Systems, Inc. ("Quickturn"), Cadence Design Systems, Inc. ("Cadence"), and CDSI Acquisition, Inc. entered into an Amendment No.1 to the Agreement and Plan of Merger (the "Merger Agreement") dated as of December 8, 1998 to correct a typographical error. ITEM 7. FINANCIAL STATEMENTS AND EXHIBITS. --------------------------------- (c) Exhibits -------- 2.1 Amendment No. 1 dated as of December 16, 1998 to Agreement and Plan of Merger, dated as of December 8, 1998, by and among Quickturn Design Systems, Inc., Cadence Design Systems, Inc. and CDSI Acquisition, 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: December 21, 1998 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. 1 dated as of December 16, 1998 to Agreement and Plan of Merger, dated as of December 8, 1998, by and among Quickturn Design Systems, Inc., Cadence Design Systems, Inc. and CDSI Acquisition, Inc.