MKS INC — Director's Dealing 2012

Feb 24, 2012

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: MKS INSTRUMENTS INC (MKSI)
CIK: 0001049502
Period of Report: 2012-02-23

Reporting Person: Lee John Tseng-Chung (Sr. VP, Controls & PFMC)

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2012-02-23	Restricted Stock Unit	$	A	5959.949	Acquired		Common Stock (5959.949)	Direct
2012-02-23	Restricted Stock Unit	$	A	3973.299	Acquired		Common Stock (3973.299)	Direct

Footnotes

F1: Each restricted stock unit represents the contingent right to receive one share of common stock of MKS Instruments, Inc.

F2: These RSUs are subject to the achievement of performance criteria determined in the first year of the grant and thereafter vests in equal annual installments over three years.

F3: The RSUs vest in equal annual installments over three years.