Ramakumar Mayampurath - 08 Feb 2026 Form 4 Insider Report for MKS INC (MKSI)

Role: EVP & CFO
Signature: /s/ M. Kathryn Rickards, attorney-in-fact
Issuer symbol: MKSI
Transactions as of: 08 Feb 2026
Net transactions value: $0
Form type: 4
Filing time: 09 Feb 2026, 13:54:24 UTC
Previous filing: 18 Nov 2025
Next filing: 18 Feb 2026
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Mayampurath Ramakumar	EVP & CFO	C/O MKS INC., 2 TECH DRIVE, ANDOVER	/s/ M. Kathryn Rickards, attorney-in-fact	09 Feb 2026	0001859332

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		+8,878	+54%		25,280	08 Feb 2026	Common Stock	8,878		Direct	F1, F2

* 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 Inc.
F2	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.