MKS INC — Director's Dealing 2015

May 6, 2015

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: MKS INSTRUMENTS INC (MKSI)
CIK: 0001049502
Period of Report: 2015-05-04

Reporting Person: Mora Elizabeth (Director)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2015-05-04	Common Stock	S	2800	$35.391	Disposed	7773.548	Direct
2015-05-04	Common Stock	A	3959.276	—	Acquired	11732.824	Direct

Footnotes

F1: This transaction was executed in multiple trades at prices ranging from $35.39 to $35.40. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide, upon request, the full information regarding the number of shares and prices at which the transaction was effected.

F2: This RSU grant fully vests on the day prior to the first annual meeting of shareholders following the date of grant (or if no such meeting is held within 13 months after the date of grant, on the 13 month anniversary of the date of grant).

F3: Each restricted stock unit represents the contingent right to receive one share of common stock of MKS Instruments, Inc.