MKS INC — Director's Dealing 2014

Feb 27, 2014

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: MKS INSTRUMENTS INC (MKSI)
CIK: 0001049502
Period of Report: 2014-02-24

Reporting Person: Lee John Tseng-Chung (Sr. VP and GM, Business Units)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2014-02-24	Common Stock	M	1947.267	—	Acquired	2911.077	Direct
2014-02-24	Common Stock	M	1324	—	Acquired	4235.077	Direct
2014-02-24	Common Stock	F	1065	$30.02	Disposed	3170.077	Direct
2014-02-25	Common Stock	M	2862.3	—	Acquired	6032.377	Direct
2014-02-25	Common Stock	M	2105	—	Acquired	8137.377	Direct
2014-02-25	Common Stock	F	1618	$29.77	Disposed	6519.377	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2014-02-24	Restricted Stock Unit	$	M	1947.267	Disposed		Common Stock (1947.267)	Direct
2014-02-24	Restricted Stock Unit	$	M	1324	Disposed		Common Stock (1324)	Direct
2014-02-25	Restricted Stock Unit	$	M	2862.3	Disposed		Common Stock (2862.3)	Direct
2014-02-25	Restricted Stock Unit	$	M	2105	Disposed		Common Stock (2105)	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.