[Form 4] MKS Inc. Insider Trading Activity

Rhea-AI Filing Summary

John Edward Williams, EVP & GM, PSD of MKS Inc. (MKSI), reported restricted stock units (RSUs) vesting on 08/15/2025. A grant of 947.285 RSUs vested (each RSU converts to one share), which increased the reporting person’s beneficial ownership of common stock to 7,343.75 shares on a direct basis. The company withheld 308 shares to satisfy tax withholding obligations at a price shown of $104.73; the withholding was not a discretionary sale by the reporting person. The transactions were reported on Form 4 and executed under codes indicating vesting and tax-withholding treatment.

Insights

Compensation/Corporate Governance Analyst

TL;DR: Routine RSU vesting and tax-withholding; indicates continued alignment via equity compensation, no discretionary sale reported.

The filing documents the scheduled vesting of 947.285 RSUs for an executive, increasing direct beneficial ownership to 7,343.75 shares. The company withheld 308 shares to meet tax obligations at a reported price of $104.73, and the filing explicitly states this withholding was not a discretionary trade by the reporting person. This is a standard compensation-related disclosure rather than an opportunistic insider sale or purchase, so it is typically considered neutral from a market-sentiment perspective but does reflect ongoing equity-based retention incentives.

Securities/Compliance Specialist

TL;DR: Form 4 correctly records vesting and withholding; no compliance red flags present in the disclosed transactions.

The Form 4 shows transactions dated 08/15/2025 with code M for vesting of derivative securities (RSUs) and code F for shares withheld to satisfy tax withholding. The explanatory note clarifies the nature of the withholding. The form is signed by an attorney-in-fact and lists the filer as one reporting person. Based on the data provided, disclosure appears complete and consistent with standard Section 16 reporting obligations.

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

OMB APPROVAL

OMB Number:			3235-0287
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hours per response:			0.5

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)
08/15/2025

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
Common Stock	08/15/2025		M		947.285	A	(1)	3,948.099	D
Common Stock	08/15/2025		F(2)		308	D	$104.73	3,640.099	D

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)	08/15/2025		M			947.285	(3)	(3)	Common Stock	947.285	(1)	7,343.75	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 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.

3. These RSUs vest in two equal annual installments commencing on August 15, 2024, provided that if, in any vesting year, August 15th is not a business day, such vesting shall occur on the next business day.

	/s/ James Kruger, attorney-in-fact	08/18/2025
	** 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 did MKSI insider John Edward Williams report on Form 4?

The filing reports the vesting of 947.285 RSUs on 08/15/2025, increasing his direct beneficial ownership to 7,343.75 shares.

Why were 308 MKSI shares listed as disposed of on the Form 4?

The 308 shares were withheld by MKS Inc. to satisfy tax withholding obligations triggered by RSU vesting; the filing states this was not a discretionary sale.

What price is shown for the shares withheld for taxes?

The filing shows a price of $104.73 associated with the reported withholding of 308 shares.

Does the Form 4 indicate any voluntary insider sales or purchases?

No; the filing indicates vesting of RSUs and company withholding for taxes and explicitly states the withholding was not a discretionary trade by the reporting person.

What is the reporting person’s role at MKSI?

The reporting person is listed as an Officer with title EVP & GM, PSD and also a Director.