MKS INC — Director's Dealing 2026

Feb 18, 2026

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: MKS INC (MKSI)
CIK: 0001049502
Period of Report: 2026-02-17

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

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2026-02-17	Common Stock	M	3450.859	—	Acquired	54611.008	Direct
2026-02-17	Common Stock	M	1787.735	—	Acquired	56398.743	Direct
2026-02-17	Common Stock	M	562.54	—	Acquired	56961.283	Direct
2026-02-17	Common Stock	M	1576	—	Acquired	58537.283	Direct
2026-02-17	Common Stock	M	2336	—	Acquired	60873.283	Direct
2026-02-17	Common Stock	M	2493	—	Acquired	63366.283	Direct
2026-02-17	Common Stock	F	5317.798	$260.74	Disposed	58048.485	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2026-02-17	Restricted Stock Unit	$	A	3327.755	Acquired		Common Stock (3327.755)	Direct
2026-02-17	Restricted Stock Unit	$	M	3450.859	Disposed		Common Stock (3450.859)	Direct
2026-02-17	Restricted Stock Unit	$	M	1787.735	Disposed		Common Stock (1787.735)	Direct
2026-02-17	Restricted Stock Unit	$	M	562.54	Disposed		Common Stock (562.54)	Direct
2026-02-17	Restricted Stock Unit	$	M	1576	Disposed		Common Stock (1576)	Direct
2026-02-17	Restricted Stock Unit	$	M	2336	Disposed		Common Stock (2336)	Direct
2026-02-17	Restricted Stock Unit	$	M	2493	Disposed		Common Stock (2493)	Direct

Footnotes

F1: Each restricted stock unit (RSU) represents the contingent right to receive one share of common stock of MKS Inc.

F2: These shares were withheld by MKS 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, 2027, 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 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.

F5: 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.

F6: 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.

F7: 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.

F8: These RSUs were subject to performance criteria, the achievement of which was determined on February 8, 2026, and thereafter vest in three equal annual installments beginning 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.

F9: 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.