MKS INC — Director's Dealing 2012

Apr 12, 2012

SEC Form 5/A — Form 5/A

Issuer: MKS INSTRUMENTS INC (MKSI)
CIK: 0001049502
Period of Report: 2011-12-31

Reporting Person: STEWART WILLIAM D (VP/GM, Vacuum Products)

Holdings (Derivative)

Security	Exercise Price	Expiration	Underlying	Shares	Ownership
Restricted Stock Unit	$		Common Stock (1584.284)	1584.284	Indirect
Restricted Stock Unit	$		Common Stock (4400)	4400	Indirect

Footnotes

F1: This indirect holding was mistakenly omitted from the original Form 5 filed.

F2: Each restricted stock unit represents the contingent right to receive one share of common stock of MKS Instruments, Inc.

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

F4: 100% vests three years from the grant date of May 26, 2009 for 2,600 shares and April 9, 2010 for 1,800 shares.