MKS INC (MKSI) EVP John Edward Williams sells 2,042.625 shares

Rhea-AI Filing Summary

MKS INC executive John Edward Williams, EVP & GM, PSD, reported an open-market sale of 2,042.625 shares of common stock on February 20, 2026 at a weighted average price of $256.4075 per share. After this sale, he directly owns 3,640.099 common shares. The sale was executed in multiple trades between $256.3902 and $257.150 per share.

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)
02/20/2026

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
Common Stock	02/20/2026		S		2,042.625	D	$256.4075(1)	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

Explanation of Responses:

1. This transaction was executed in multiple trades at prices ranging from $256.3902 to $257.150. The price reported above reflects the weighted average sale price. The reporting person hereby undertakes to provide, upon request, the full information regarding the number of shares and prices at which the transaction was effected.

	/s/ M. Kathryn Rickards, attorney-in-fact	02/23/2026
	** 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).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

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

MKS INC reported that EVP & GM, PSD, John Edward Williams sold 2,042.625 shares of common stock in an open-market transaction on February 20, 2026. This Form 4 filing details the sale and his updated direct share ownership after the trade.

At what price did John Edward Williams sell MKSI common stock?

John Edward Williams sold MKSI common stock at a weighted average price of $256.4075 per share. According to the filing, the transaction was executed in multiple trades, with individual prices ranging from $256.3902 to $257.150 per share during the same trading day.

How many MKS INC shares does John Edward Williams own after the sale?

Following the reported sale, John Edward Williams directly owns 3,640.099 shares of MKS INC common stock. The Form 4 specifies this post-transaction balance, reflecting his remaining direct equity stake after the February 20, 2026 open-market sale.

What was the size of the MKSI share sale reported on this Form 4?

The Form 4 shows that John Edward Williams sold 2,042.625 shares of MKS INC common stock. This transaction was classified as an open-market or private sale, coded “S,” and represents a reduction in his directly held shares as disclosed in the filing.

How was the reported sale price for John Edward Williams’ MKSI shares calculated?

The reported sale price of $256.4075 per share is a weighted average across multiple trades. The footnote explains that individual trades occurred between $256.3902 and $257.150, and full trade-by-trade price and volume details are available upon request.

What role does John Edward Williams hold at MKS INC related to this Form 4?

John Edward Williams is identified as an officer of MKS INC, serving as EVP & GM, PSD. His position as an executive officer requires reporting changes in his beneficial ownership of company stock through Form 4 filings with the SEC.