Kathleen Flaherty Burke - 15 Feb 2024 Form 4 Insider Report for MKS INSTRUMENTS INC (MKSI)

Role: EVP, GC & Secretary
Signature: /s/ M. Kathryn Rickards, attorney-in-fact
Issuer symbol: MKSI
Transactions as of: 15 Feb 2024
Net transactions value: -$600,001
Form type: 4
Filing time: 16 Feb 2024, 15:05:47 UTC
Previous filing: 06 Feb 2024
Next filing: 04 Mar 2024
SEC: View on sec.gov

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	MKSI	Common Stock	Options Exercise		+2,033	+4.7%		44,896	15 Feb 2024	Direct	F1
transaction	MKSI	Common Stock	Options Exercise		+1,017	+2.3%		45,913	15 Feb 2024	Direct	F1
transaction	MKSI	Common Stock	Options Exercise		+2,287	+5%		48,200	15 Feb 2024	Direct	F1
transaction	MKSI	Common Stock	Options Exercise		+1,645	+3.4%		49,845	15 Feb 2024	Direct	F1
transaction	MKSI	Common Stock	Options Exercise		+3,608	+7.2%		53,453	15 Feb 2024	Direct	F1
transaction	MKSI	Common Stock	Options Exercise		+1,869	+3.5%		55,322	15 Feb 2024	Direct	F1
transaction	MKSI	Common Stock	Tax liability	$600,001	-4,912	-8.9%	$122.15	50,410	15 Feb 2024	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	Award		+4,945	+18%		32,292	15 Feb 2024	Common Stock	4,945		Direct	F1, F3
transaction	MKSI	Restricted Stock Unit	Options Exercise		-2,033	-6.3%		30,260	15 Feb 2024	Common Stock	2,033		Direct	F1, F4
transaction	MKSI	Restricted Stock Unit	Options Exercise		-1,017	-3.4%		29,243	15 Feb 2024	Common Stock	1,017		Direct	F1, F5
transaction	MKSI	Restricted Stock Unit	Options Exercise		-2,287	-7.8%		26,956	15 Feb 2024	Common Stock	2,287		Direct	F1, F6
transaction	MKSI	Restricted Stock Unit	Options Exercise		-1,645	-6.1%		25,311	15 Feb 2024	Common Stock	1,645		Direct	F1, F7
transaction	MKSI	Restricted Stock Unit	Options Exercise		-3,608	-14%		21,703	15 Feb 2024	Common Stock	3,608		Direct	F1, F8
transaction	MKSI	Restricted Stock Unit	Options Exercise		-1,869	-8.6%		19,834	15 Feb 2024	Common Stock	1,869		Direct	F1, F9

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

Explanation of Responses:

Id	Content
F1	Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Instruments, Inc.
F2	These shares were withheld by MKS Instruments, Inc. to satisfy the tax withholding obligations triggered by the vesting of RSUs and do not represent a discretionary trade by the reporting person.
F3	These RSUs vest in three equal annual installments commencing on February 15, 2025, provided that if, in any vesting year, February 15th is not a business day, such vesting shall occur on the next business day.
F4	These RSUs were subject to performance criteria, the achievement of which was determined on January 21, 2022, and thereafter vest in three equal annual installments beginning on February 15, 2022, provided that if, in any vesting year, February 15th is not a business day, such vesting shall occur on the next business day.
F5	These RSUs vest in three equal annual installments commencing on February 15, 2022, provided that if, in any vesting year, February 15th is not a business day, such vesting shall occur on the next business day.
F6	These RSUs were subject to performance criteria, the achievement of which was determined on February 8, 2023, and thereafter vest in three equal annual installments beginning on February 15, 2023, provided that if, in any vesting year, February 15th is not a business day, such vesting shall occur on the next business day.
F7	These RSUs vest in three equal annual installments commencing on February 15, 2023, provided that if, in any vesting year, February 15th is not a business day, such vesting shall occur on the next business day.
F8	These RSUs were subject to performance criteria, the achievement of which was determined on February 5, 2024, and thereafter vest in three equal annual installments beginning on February 15, 2024, provided that if, in any vesting year, February 15th is not a business day, such vesting shall occur on the next business day.
F9	These RSUs vest in three equal annual installments commencing on February 15, 2024, provided that if, in any vesting year, February 15th is not a business day, such vesting shall occur on the next business day.