[Form 4] MKS Inc. Insider Trading Activity

Rhea-AI Filing Summary

Elizabeth Mora, a director of MKS Inc. (MKSI), reported a sale of 300 shares of common stock on 09/02/2025 at a price of $99.85 per share. The Form 4 shows the transaction was executed pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on February 19, 2025. After the reported sale, the filing lists 19,263.394 shares beneficially owned by the reporting person. The Form 4 was signed by an attorney-in-fact on 09/03/2025. The filing identifies the reporter as a director and indicates this is a single-person Form 4 filing.

Positive

• Transaction executed under a Rule 10b5-1 trading plan, indicating pre-planned compliance with insider trading rules
• Timely disclosure filed (Form 4) and signed by attorney-in-fact the day after the transaction

Negative

• Sale reduced beneficial ownership by 300 shares to 19,263.394 shares
• Disposal realized at $99.85, which may be viewed negatively if investors expected continued accumulation

Insights

Corporate Governance Expert

TL;DR: Routine director sale executed under a pre-established 10b5-1 plan; governance transparency maintained by timely disclosure.

The reported sale of 300 shares appears to be a standard insider disposition carried out under a Rule 10b5-1 plan adopted on February 19, 2025. Use of a 10b5-1 plan typically signals an effort to avoid claims of opportunistic trading around material events. The Form 4 was filed promptly and signed by an attorney-in-fact the day after the transaction, meeting disclosure expectations for insiders. No change in officer status or other governance actions are reported.

Securities Analyst

TL;DR: Small, disclosed share disposition by a director; transaction size is immaterial relative to total reported holdings.

The disposition of 300 shares at $99.85 reduces the reporting persons beneficial holding to 19,263.394 shares. Based solely on the numbers in the filing, the sale represents a small percentage of the insider's reported position. The use of a 10b5-1 plan reduces interpretive ambiguity about timing. There are no derivative transactions or additional securities reported on this Form 4.

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
Estimated average burden
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).

X

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^*

Mora Elizabeth

(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)

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
09/02/2025

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	09/02/2025		S(1)		300	D	$99.85	19,263.394	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 February 19, 2025.

	/s/ M. Kathryn Rickards, attorney-in-fact	09/03/2025
	** 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 did MKSI director Elizabeth Mora report on the Form 4?

The Form 4 reports a sale of 300 shares of MKS Inc. common stock on 09/02/2025 at $99.85 per share.

Was the MKSI transaction part of a trading plan?

Yes. The filing states the transaction was effected pursuant to a Rule 10b5-1 trading plan adopted on February 19, 2025.

How many MKSI shares does the reporting person own after the sale?

After the reported transaction, the Form 4 lists 19,263.394 shares beneficially owned by the reporting person.

When was the Form 4 filed and signed?

The Form 4 reports the transaction date as 09/02/2025 and shows the signature by attorney-in-fact dated 09/03/2025.

Did the Form 4 disclose any derivative securities for MKSI?

No. Table II for derivative securities contains no reported transactions or holdings in this filing.