MKS INC — Director's Dealing 2011

Mar 2, 2011

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: MKS INSTRUMENTS INC (MKSI)
CIK: 0001049502
Period of Report: 2011-03-01

Reporting Person: HANLEY PETER (Director)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2011-03-01	Common Stock	M	556	—	Acquired	14444	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2011-03-01	Restricted Stock Unit	$	M	556	Disposed		Common Stock (556)	Direct

Footnotes

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

F2: vests in 12 equal quarterly installments over a three-year period.