John Tseng-Chung Lee - 18 Feb 2025 Form 4 Insider Report for MKS INSTRUMENTS INC (MKSI)

Role: President & CEO, Director
Signature: /s/ M. Kathryn Rickards, attorney-in-fact
Issuer symbol: MKSI
Transactions as of: 18 Feb 2025
Net transactions value: -$2,833,508
Form type: 4
Filing time: 19 Feb 2025, 18:21:12 UTC
Previous filing: 11 Feb 2025
Next filing: 24 Feb 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		+14,041	+12%		126,730	18 Feb 2025	Direct	F1
transaction	MKSI	Common Stock	Options Exercise		+6,735	+5.3%		133,465	18 Feb 2025	Direct	F1
transaction	MKSI	Common Stock	Options Exercise		+22,088	+17%		155,553	18 Feb 2025	Direct	F1
transaction	MKSI	Common Stock	Options Exercise		+7,654	+4.9%		163,207	18 Feb 2025	Direct	F1
transaction	MKSI	Common Stock	Options Exercise		+4,035	+2.5%		167,242	18 Feb 2025	Direct	F1
transaction	MKSI	Common Stock	Options Exercise		+7,207	+4.3%		174,449	18 Feb 2025	Direct	F1
transaction	MKSI	Common Stock	Tax liability	$2,833,508	-27,332	-16%	$103.67	147,117	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		+37,925	+33%		151,917	18 Feb 2025	Common Stock	37,925		Direct	F1, F3
transaction	MKSI	Restricted Stock Unit	Options Exercise		-14,041	-9.2%		137,875	18 Feb 2025	Common Stock	14,041		Direct	F1, F4
transaction	MKSI	Restricted Stock Unit	Options Exercise		-6,735	-4.9%		131,140	18 Feb 2025	Common Stock	6,735		Direct	F1, F5
transaction	MKSI	Restricted Stock Unit	Options Exercise		-22,088	-17%		109,052	18 Feb 2025	Common Stock	22,088		Direct	F1, F6
transaction	MKSI	Restricted Stock Unit	Options Exercise		-7,654	-7%		101,398	18 Feb 2025	Common Stock	7,654		Direct	F1, F7
transaction	MKSI	Restricted Stock Unit	Options Exercise		-4,035	-4%		97,363	18 Feb 2025	Common Stock	4,035		Direct	F1, F8
transaction	MKSI	Restricted Stock Unit	Options Exercise		-7,207	-7.4%		90,156	18 Feb 2025	Common Stock	7,207		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.