Kathleen Flaherty Burke - Oct 28, 2021 Form 4 Insider Report for MKS INSTRUMENTS INC (MKSI)

Role: Sr. VP, GC & Secretary
Signature: /s/ M. Kathryn Rickards, attorney-in-fact
Stock symbol: MKSI
Transactions as of: Oct 28, 2021
Transactions value $: -$140,931
Form type: 4
Date filed: 10/29/2021, 05:23 PM
Next filing: Jan 24, 2022

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	MKSI	Common Stock	Options Exercise		+2.18K	+5.51%		41.7K	Oct 28, 2021	Direct	F1
transaction	MKSI	Common Stock	Tax liability	-$141K	-967	-2.32%	$145.74	40.7K	Oct 28, 2021	Direct	F2

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	MKSI	Restricted Stock Unit	Options Exercise		-2.18K	-13.19%		14.3K	Oct 28, 2021	Common Stock	2.18K		Direct	F1, F3

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
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 vest in two equal annual installments on each of the second anniversary and third anniversary of the date of grant, October 28, 2019.