MKS Inc. (MKSI) awards EVP 2,973 performance-based RSUs

Rhea-AI Filing Summary

MKS Inc. executive John Edward Williams, EVP & GM, PSD, received an award of 2,973.357 performance-based restricted stock units (RSUs) on February 8, 2026. Each RSU represents the right to receive one share of MKS common stock.

The performance-based RSUs vest in three equal annual installments beginning on February 15, 2026, with vesting in later years occurring on February 15 or the next business day. After this grant, Williams beneficially owns 10,317.107 derivative securities related to MKS common stock.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

Williams John Edward

(Last) (First) (Middle)

C/O MKS INC.

2 TECH DRIVE

(Street)

ANDOVER MA 01810

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
MKS INC [ MKSI ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	EVP & GM, PSD

3. Date of Earliest Transaction (Month/Day/Year)
02/08/2026

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Restricted Stock Unit	(1)	02/08/2026		A		2,973.357		(2)	(2)	Common Stock	2,973.357	(1)	10,317.107	D

Explanation of Responses:

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

2. 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.

	/s/ M. Kathryn Rickards, attorney-in-fact	02/09/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
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FAQ

What insider transaction did MKS Inc. (MKSI) report for John Edward Williams?

MKS Inc. reported that EVP & GM, PSD, John Edward Williams received an award of 2,973.357 performance-based restricted stock units (RSUs) on February 8, 2026. These RSUs represent contingent rights to receive an equal number of MKS common shares, subject to vesting conditions.

How many restricted stock units did the MKS Inc. EVP receive in this Form 4?

The MKS Inc. executive received 2,973.357 restricted stock units in this transaction. Each RSU corresponds to one share of MKS common stock, awarded at a price of $0.00 per unit as part of performance-based compensation disclosed in the Form 4 filing.

What is the vesting schedule for the 2,973.357 MKS Inc. RSUs reported?

The 2,973.357 performance-based RSUs vest in three equal annual installments starting February 15, 2026. If February 15 is not a business day in any vesting year, vesting moves to the next business day, subject to the original performance criteria already determined.

What does each MKS Inc. restricted stock unit reported in this Form 4 represent?

Each MKS Inc. restricted stock unit represents a contingent right to receive one share of the company’s common stock. The rights become actual shares only as the RSUs vest over time, based on the performance criteria and vesting schedule described in the filing.

How many derivative securities does the MKS Inc. EVP own after this RSU award?

Following this RSU grant, John Edward Williams beneficially owns 10,317.107 derivative securities related to MKS Inc. common stock. This total reflects his updated holdings of restricted stock units after the February 8, 2026 performance-based award reported in the Form 4.

What role does John Edward Williams hold at MKS Inc. in this insider filing?

In this insider filing, John Edward Williams is identified as an officer of MKS Inc. with the title EVP & GM, PSD. The Form 4 reports an equity-based compensation award to him in the form of performance-based restricted stock units tied to MKS common stock.