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

Role: President & CEO, Director
Signature: /s/ M. Kathryn Rickards, attorney-in-fact
Stock symbol: MKSI
Transactions as of: Feb 18, 2025
Transactions value $: -$2,833,508
Form type: 4
Date filed: 2/19/2025, 06:21 PM
Previous filing: Feb 11, 2025
Next filing: Feb 24, 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		+14K	+12.46%		127K	Feb 18, 2025	Direct	F1
transaction	MKSI	Common Stock	Options Exercise		+6.74K	+5.31%		133K	Feb 18, 2025	Direct	F1
transaction	MKSI	Common Stock	Options Exercise		+22.1K	+16.55%		156K	Feb 18, 2025	Direct	F1
transaction	MKSI	Common Stock	Options Exercise		+7.65K	+4.92%		163K	Feb 18, 2025	Direct	F1
transaction	MKSI	Common Stock	Options Exercise		+4.04K	+2.47%		167K	Feb 18, 2025	Direct	F1
transaction	MKSI	Common Stock	Options Exercise		+7.21K	+4.31%		174K	Feb 18, 2025	Direct	F1
transaction	MKSI	Common Stock	Tax liability	-$2.83M	-27.3K	-15.67%	$103.67	147K	Feb 18, 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		+37.9K	+33.27%		152K	Feb 18, 2025	Common Stock	37.9K		Direct	F1, F3
transaction	MKSI	Restricted Stock Unit	Options Exercise		-14K	-9.24%		138K	Feb 18, 2025	Common Stock	14K		Direct	F1, F4
transaction	MKSI	Restricted Stock Unit	Options Exercise		-6.74K	-4.89%		131K	Feb 18, 2025	Common Stock	6.74K		Direct	F1, F5
transaction	MKSI	Restricted Stock Unit	Options Exercise		-22.1K	-16.84%		109K	Feb 18, 2025	Common Stock	22.1K		Direct	F1, F6
transaction	MKSI	Restricted Stock Unit	Options Exercise		-7.65K	-7.02%		101K	Feb 18, 2025	Common Stock	7.65K		Direct	F1, F7
transaction	MKSI	Restricted Stock Unit	Options Exercise		-4.04K	-3.98%		97.4K	Feb 18, 2025	Common Stock	4.04K		Direct	F1, F8
transaction	MKSI	Restricted Stock Unit	Options Exercise		-7.21K	-7.4%		90.2K	Feb 18, 2025	Common Stock	7.21K		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.