As filed with the Securities and Exchange Commission on June 14, 2002 Registration No. 333-_____ ================================================================================ SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM S-8 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 MKS INSTRUMENTS, INC. (Exact Name of Registrant as Specified in Its Charter) MASSACHUSETTS 04-2277512 (State or Other Jurisdiction of (I.R.S. Employer Incorporation or Organization) Identification Number) SIX SHATTUCK ROAD, ANDOVER, MASSACHUSETTS 01810 (Address of Principal Executive Offices) (Zip Code) INTERNATIONAL EMPLOYEE STOCK PURCHASE PLAN, AS AMENDED (Full Title of the Plan) JOHN R. BERTUCCI CHAIRMAN AND CHIEF EXECUTIVE OFFICER MKS INSTRUMENTS, INC. SIX SHATTUCK ROAD ANDOVER, MA 01810 (Name and Address of Agent For Service) (978) 975-2350 (Telephone Number, Including Area Code, of Agent For Service) CALCULATION OF REGISTRATION FEE Proposed Maximum Proposed Maximum Title of Securities Amount to be Offering Price Per Aggregate Offering Amount of to be Registered Registered(1) Share Price Registration Fee ------------------- ------------- ------------------ ------------------ ---------------- Common Stock, no 25,000 $22.86 $571,500 $52.58 par value per share (1) Estimated solely for the purpose of calculating the registration fee pursuant to Rules 457(c) and 457(h) of the Securities Act of 1933, as amended, and based upon the average of the high and low prices of the Registrant's Common Stock as reported on the Nasdaq National Market on June 12, 2002. STATEMENT OF INCORPORATION BY REFERENCE Except as otherwise set forth below, this Registration Statement on Form S-8 incorporates by reference the contents of the Registration Statement on Form S-8, File No. 333-31224, relating to the Registrant's International Employee Stock Purchase Plan. SIGNATURES Pursuant to the requirements of the Securities Act, the Registrant certifies that it has reasonable grounds to believe that it meets all of the requirements for filing on Form S-8 and has duly caused this Registration Statement to be signed on its behalf by the undersigned, thereunto duly authorized, in Andover, Massachusetts on June 14, 2002. MKS INSTRUMENTS, INC. By: /s/ John R. Bertucci -------------------- John R. Bertucci Chairman of the Board and Chief Executive Officer POWER OF ATTORNEY AND SIGNATURES We, the undersigned officers and directors of MKS Instruments, Inc. hereby severally constitute and appoint John R. Bertucci, Ronald C. Weigner and Mark G. Borden, and each of them singly, our true and lawful attorneys with full power to them, and each of them singly, to sign for us and in our names in the capacities indicated below, the Registration Statement on Form S-8 filed herewith and any and all subsequent amendments to said Registration Statement, and generally to do all such things in our names and behalf in our capacities as officers and directors to enable MKS Instruments, Inc. to comply with all requirements of the Securities and Exchange Commission, hereby ratifying and confirming our signatures as they may be signed by said attorneys, or any of them, to said Registration Statement and any and all amendments thereto. PURSUANT TO THE REQUIREMENTS OF THE SECURITIES ACT, THIS REGISTRATION STATEMENT HAS BEEN SIGNED BY THE FOLLOWING PERSONS IN THE CAPACITIES AND ON THE DATES INDICATED. Signature Title Date --------- ----- ---- /s/ John R. Bertucci Chairman of the Board and Chief June 14, 2002 --------------------- John R. Bertucci Executive Officer (Principal Executive Officer) /s/ Ronald C. Weigner Vice President and Chief June 14, 2002 ---------------------- Ronald C. Weigner Financial Officer (Principal Financial Officer and Principal Accounting Officer) /s/ Robert R. Anderson Director June 14, 2002 ------------------------- Robert R. Anderson /s/ James G. Berges Director June 14, 2002 ------------------------- James G. Berges /s/ Richard S. Chute Director June 14, 2002 -------------------------- Richard S. Chute /s/ Hans-Jochen Kahl Director June 14, 2002 ------------------------- Hans-Jochen Kahl /s/ Owen W. Robbins Director June 14, 2002 ------------------------ Owen W. Robbins /s/ Louis P. Valente Director June 14, 2002 -------------------------- Louis P. Valente EXHIBIT INDEX Exhibit Number Description ------ ----------- 4.1 (1) Restated Articles of Organization of the Registrant. 4.2 (2) Articles of Amendment. 4.3 (3) Articles of Amendment. 4.4 (4) Amended and Restated By-Laws of the Registrant. 4.5 (4) Specimen Certificate for Common Stock of the Registrant. 5.1 Opinion of Hale and Dorr LLP. 23.1 Consent of Hale and Dorr LLP (included in Exhibit 5.1). 23.2 Consent of PricewaterhouseCoopers LLP. 23.3 Consent of KPMG LLP. 24.1 Power of Attorney (included in the signature pages of this Registration Statement). -------------------------------------------------------------------------------- (1) Incorporated herein by reference from the Registrant's Registration Statement on Form S-4 (File No. 333-49738) originally filed with the Securities and Exchange Commission on December 13, 2000, as amended. (2) Incorporated herein by reference from the Registrant's Quarterly Report on Form 10-Q originally filed with the Securities and Exchange Commission on August 14, 2001. (3) Incorporated herein by reference from the Registrant's Definitive Proxy originally filed with the Securities and Exchange Commission on April 16, 2002. (4) Incorporated herein by reference from the Registrant's Registration Statement on Form S-1 (File No. 333-71363) originally filed with the Securities and Exchange Commission on January 28, 1999, as amended.