David Philip Henry - 18 Feb 2025 Form 4 Insider Report for MKS INSTRUMENTS INC (MKSI)

Role: EVP, Operations & Corp Mktg
Signature: /s/ M. Kathryn Rickards, attorney-in-fact
Issuer symbol: MKSI
Transactions as of: 18 Feb 2025
Net transactions value: -$245,905
Form type: 4
Filing time: 19 Feb 2025, 18:29:40 UTC
Previous filing: 11 Feb 2025
Next filing: 07 Jul 2025
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		+1,528	+9.1%		18,306	18 Feb 2025	Direct	F1
transaction	MKSI	Common Stock	Options Exercise		+1,099	+6%		19,405	18 Feb 2025	Direct	F1
transaction	MKSI	Common Stock	Options Exercise		+2,406	+12%		21,811	18 Feb 2025	Direct	F1
transaction	MKSI	Common Stock	Options Exercise		+1,246	+5.7%		23,057	18 Feb 2025	Direct	F1
transaction	MKSI	Common Stock	Options Exercise		+456	+2%		23,513	18 Feb 2025	Direct	F1
transaction	MKSI	Common Stock	Options Exercise		+1,278	+5.4%		24,791	18 Feb 2025	Direct	F1
transaction	MKSI	Common Stock	Tax liability	$245,905	-2,372	-9.6%	$103.67	22,419	18 Feb 2025	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		+6,163	+41%		21,300	18 Feb 2025	Common Stock	6,163		Direct	F1, F3
transaction	MKSI	Restricted Stock Unit	Options Exercise		-1,528	-7.2%		19,771	18 Feb 2025	Common Stock	1,528		Direct	F1, F4
transaction	MKSI	Restricted Stock Unit	Options Exercise		-1,099	-5.6%		18,672	18 Feb 2025	Common Stock	1,099		Direct	F1, F5
transaction	MKSI	Restricted Stock Unit	Options Exercise		-2,406	-13%		16,266	18 Feb 2025	Common Stock	2,406		Direct	F1, F6
transaction	MKSI	Restricted Stock Unit	Options Exercise		-1,246	-7.7%		15,020	18 Feb 2025	Common Stock	1,246		Direct	F1, F7
transaction	MKSI	Restricted Stock Unit	Options Exercise		-456	-3%		14,564	18 Feb 2025	Common Stock	456		Direct	F1, F8
transaction	MKSI	Restricted Stock Unit	Options Exercise		-1,278	-8.8%		13,286	18 Feb 2025	Common Stock	1,278		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, 2026, 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 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.
F5	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.
F6	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.
F7	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.
F8	These RSUs were subject to performance criteria, the achievement of which was determined on February 10, 2025, and thereafter vest in three equal annual installments beginning 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.
F9	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.