MKS INC — Director's Dealing 2012

Feb 24, 2012

SEC Form 4/A — Form 4/A

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

Reporting Person: Loomis Paul (VP & GM, Astex)

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2012-02-23	Restricted Stock Unit	$	A	3178.64	Acquired		Common Stock (3178.64)	Direct

Footnotes

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

F2: This transaction was previously reported, however, the footnotes for section 6 were not accurate. This amendment updates the footnotes.

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