MKS INC (MKSI) accounting officer sells 1,466 shares in open market

Rhea-AI Filing Summary

MKS INC vice president and chief accounting officer Michelle M. McCarthy reported selling a total of 1,466 shares of common stock in open-market transactions on February 20, 2026. The sales were executed at weighted average prices of $249.5674 and $250.3479 per share, in multiple trades within stated price ranges. Following these sales, her directly held common stock position reported in this filing was reduced to zero shares.

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^*

McCarthy Michelle M

(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)
	VP & Chief Accounting Officer

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		650	D	$249.5674(1)	816	D
Common Stock	02/20/2026		S		816	D	$250.3479(2)	0	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 $249.070 to $250.030. 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.

2. This transaction was executed in multiple trades at prices ranging from $250.160 to $250.790. 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 Michelle McCarthy?

MKS INC reported that officer Michelle M. McCarthy sold 1,466 shares of common stock on February 20, 2026. The Form 4 describes two open-market sale transactions that together eliminated the directly owned shares disclosed in this filing.

How many MKS INC (MKSI) shares did Michelle McCarthy sell and at what prices?

Michelle McCarthy sold 650 shares at a weighted average price of $249.5674 and 816 shares at $250.3479. Footnotes state each transaction occurred through multiple trades within narrow price ranges around those averages.

What is Michelle McCarthy’s role at MKS INC (MKSI) in this Form 4 filing?

The filing identifies Michelle M. McCarthy as an officer of MKS INC, serving as vice president and chief accounting officer. Her status as an officer makes these open-market stock sales subject to Form 4 reporting requirements for insiders.

How did the reported sales affect Michelle McCarthy’s MKS INC (MKSI) shareholdings?

After selling 1,466 shares in total, the Form 4 shows Michelle McCarthy with zero directly owned common shares. One line shows 816 shares remaining after the first sale, and the second transaction reduces that reported direct holding to none.

Were the MKS INC (MKSI) insider sales by Michelle McCarthy single trades or multiple executions?

Footnotes explain that each reported sale was executed in multiple trades within specified price ranges. The prices $249.5674 and $250.3479 represent weighted averages, and full trade-by-trade details are available on request from the reporting person.