MKS INC — Director's Dealing 2025

Feb 19, 2025

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: MKS INSTRUMENTS INC (MKSI)
CIK: 0001049502
Period of Report: 2025-02-18

Reporting Person: Burke Kathleen Flaherty (EVP, GC & Secretary)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2025-02-18	Common Stock	M	2286.756	—	Acquired	45533.316	Direct
2025-02-18	Common Stock	M	1645.076	—	Acquired	47178.392	Direct
2025-02-18	Common Stock	M	3608	—	Acquired	50786.392	Direct
2025-02-18	Common Stock	M	1870	—	Acquired	52656.392	Direct
2025-02-18	Common Stock	M	588.03	—	Acquired	53244.422	Direct
2025-02-18	Common Stock	M	1648	—	Acquired	54892.422	Direct
2025-02-18	Common Stock	F	3970	$103.67	Disposed	50922.422	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2025-02-18	Restricted Stock Unit	$	A	7822.13	Acquired		Common Stock (7822.13)	Direct
2025-02-18	Restricted Stock Unit	$	M	2286.756	Disposed		Common Stock (2286.756)	Direct
2025-02-18	Restricted Stock Unit	$	M	1645.076	Disposed		Common Stock (1645.076)	Direct
2025-02-18	Restricted Stock Unit	$	M	3608	Disposed		Common Stock (3608)	Direct
2025-02-18	Restricted Stock Unit	$	M	1870	Disposed		Common Stock (1870)	Direct
2025-02-18	Restricted Stock Unit	$	M	588.03	Disposed		Common Stock (588.03)	Direct
2025-02-18	Restricted Stock Unit	$	M	1648	Disposed		Common Stock (1648)	Direct

Footnotes

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.