MKS INC — Director's Dealing 2013

Mar 4, 2013

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: MKS INSTRUMENTS INC (MKSI)
CIK: 0001049502
Period of Report: 2013-02-28

Reporting Person: COLELLA GERARD G (President, COO)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2013-02-28	Common Stock	M	3941.817	—	Acquired	3965.492	Direct
2013-02-28	Common Stock	M	2776	—	Acquired	6741.492	Direct
2013-02-28	Common Stock	F	2191	$27.14	Disposed	4550.492	Direct
2013-03-01	Common Stock	S	4525	$27.00	Disposed	25.492	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2013-02-28	Restricted Stock Unit	$	M	3941.817	Disposed		Common Stock (3941.817)	Direct
2013-02-28	Restricted Stock Unit	$	M	2776	Disposed		Common Stock (2776)	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 effected pursuant to a Rule 10b5-1 trading plan previously adopted by the reporting person.

F3: 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.

F4: The RSUs vest in equal annual installments over three years.