[Form 4] MKS INC Insider Trading Activity

Rhea-AI Filing Summary

James Alan Schreiner, Executive Vice President & Chief Operating Officer of MKS Inc. (MKSI), reported a sale of 838 shares of MKS common stock on 09/18/2025 at a price of $124 per share. The filing states the transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on March 12, 2025. After the reported sale, the reporting person beneficially owned 23,245.694 shares, held directly. The Form 4 was signed by an attorney-in-fact on 09/19/2025. The document lists the reporting person’s address as C/O MKS Inc., 2 Tech Drive, Andover, MA 01810.

Insights

Securities Analyst

TL;DR: Routine insider sale under a 10b5-1 plan; no new disclosures beyond transaction details.

The Form 4 discloses a single non-derivative sale of 838 shares at $124 per share executed under a pre-established Rule 10b5-1 plan adopted March 12, 2025. The filing shows the insider retains 23,245.694 shares directly. As provided, the disclosure is procedural and limited to the mechanics of the trade; it does not include any company performance metrics or changes to executive roles. From a compliance perspective, the presence of a 10b5-1 plan indicates the trades were pre-planned, reducing the likelihood they were based on undisclosed material information.

Corporate Governance Expert

TL;DR: Disclosure is complete for the reported transaction and cites a 10b5-1 plan; no governance concerns evident in the filing itself.

The Form 4 provides required transaction details: date, number of shares sold, sale price, post-transaction beneficial ownership, and a statement that the trade was executed pursuant to a Rule 10b5-1 plan adopted March 12, 2025. The filing was executed by an attorney-in-fact and includes the reporting person’s officer title. There are no indications of amendments, additional transactions, or unusual ownership structures disclosed in this form.

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

1. Name and Address of Reporting Person^*

Schreiner James Alan

(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 & COO

3. Date of Earliest Transaction (Month/Day/Year)
09/18/2025

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	09/18/2025		S(1)		838	D	$124	23,245.694	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 effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on March 12, 2025.

	/s/ M. Kathryn Rickards, attorney-in-fact	09/19/2025
	** 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).
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 transaction did James Alan Schreiner report on the Form 4 for MKSI?

The Form 4 reports a sale of 838 shares of MKS Inc. common stock on 09/18/2025 at $124 per share.

Was the sale executed under a trading plan for MKSI insider James Alan Schreiner?

Yes. The filing states the transaction was effected pursuant to a Rule 10b5-1 trading plan adopted on March 12, 2025.

How many MKS shares did the reporting person own after the sale?

After the reported transaction the reporting person beneficially owned 23,245.694 shares held directly.

What is the reporting person’s role at MKS as shown on the Form 4?

The reporting person is listed as Executive Vice President & Chief Operating Officer (EVP & COO).

When was the Form 4 signed and by whom?

The Form 4 was signed by M. Kathryn Rickards, attorney-in-fact, on 09/19/2025.