MKS INC — Director's Dealing 2017

Dec 18, 2017

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: MKS INSTRUMENTS INC (MKSI)
CIK: 0001049502
Period of Report: 2017-12-14

Reporting Person: Werth Dennis L (Sr. VP, Business Units)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2017-12-14	Common Stock	M	4199	$27.79	Acquired	4199	Direct
2017-12-14	Common Stock	S	1617	$95.615	Disposed	2582	Direct
2017-12-14	Common Stock	D	1220	$95.65	Disposed	1362	Direct
2017-12-14	Common Stock	F	1362	$95.65	Disposed	0	Direct
2017-12-15	Common Stock	M	5911	$27.89	Acquired	5911	Direct
2017-12-15	Common Stock	S	2022	$97.90	Disposed	3889	Direct
2017-12-15	Common Stock	D	1682	$98.00	Disposed	2207	Direct
2017-12-15	Common Stock	F	2207	$98.00	Disposed	0	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2017-12-14	Stock Appreciation Right	$27.79	M	4199	Disposed	2018-05-17	Common Stock (4199)	Direct
2017-12-15	Stock Appreciation Right	$27.89	M	5911	Disposed	2019-04-12	Common Stock (5911)	Direct

Holdings (Non-Derivative)

Security	Shares	Ownership
Common Stock	7995.437	Indirect

Footnotes

F1: Reflects the disposition of shares to the issuer deemed to occur upon the exercise of a stock appreciation right.

F2: Shares have been withheld in satisfaction of reporting person's tax withholding obligations resulting from the exercise of stock appreciation rights.

F3: The stock appreciation right became fully vested on March 31, 2014.

F4: The stock appreciation right became fully vested on March 31, 2015.