[Form 4] MKS INC Insider Trading Activity

Rhea-AI Filing Summary

MKS Inc. executive Henry David Philip received a new performance-based equity award. On February 8, 2026, he was granted 5,521.949 restricted stock units (RSUs) at no cash cost, each representing one share of MKS Inc. common stock.

The achievement of performance criteria for these RSUs was determined on February 8, 2026. The units will vest in three equal annual installments starting on February 15, 2026, with vesting moving to the next business day if February 15 is not a business day. After this grant, Philip beneficially owned 18,808.107 derivative securities in the form of RSUs, held directly.

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^*

Henry David Philip

(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, Global Str Mktg & GM, MSD

3. Date of Earliest Transaction (Month/Day/Year)
02/08/2026

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

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)	02/08/2026		A		5,521.949		(2)	(2)	Common Stock	5,521.949	(1)	18,808.107	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 RSUs were subject to performance criteria, the achievement of which was determined on February 8, 2026, and thereafter vest in three equal annual installments beginning on February 15, 2026, provided that if, in any vesting year, February 15th is not a business day, such vesting shall occur on the next business day.

	/s/ M. Kathryn Rickards, attorney-in-fact	02/09/2026
	** 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 Henry David Philip?

Henry David Philip received 5,521.949 restricted stock units (RSUs) on February 8, 2026. Each RSU represents the right to receive one share of MKS Inc. common stock, providing additional equity-based compensation tied to the company’s future performance and continued service.

How many MKS Inc. (MKSI) RSUs does Henry David Philip hold after this grant?

After the February 8, 2026 grant, Henry David Philip beneficially owned 18,808.107 restricted stock units. These derivative securities are held directly and represent potential future shares of MKS Inc. common stock, subject to the applicable vesting schedule and performance conditions outlined in the award terms.

What are the key terms of the RSU award reported by MKS Inc. (MKSI)?

The award consists of 5,521.949 performance-based RSUs granted on February 8, 2026. The performance criteria were determined on that date, and the RSUs vest in three equal annual installments beginning February 15, 2026, subject to standard business-day adjustments for the vesting date.

How do the MKS Inc. (MKSI) RSUs granted to Henry David Philip vest over time?

The 5,521.949 RSUs vest in three equal annual installments starting on February 15, 2026. If February 15 falls on a non-business day in any vesting year, vesting occurs on the next business day, aligning the award with standard market and administrative practices.

What does each restricted stock unit (RSU) of MKS Inc. (MKSI) represent?

Each RSU represents a contingent right to receive one share of MKS Inc. common stock. Delivery of shares depends on vesting conditions being met, including the already-determined performance criteria and the passage of the scheduled vesting dates for the award.

Is there a purchase price associated with the MKS Inc. (MKSI) RSUs granted?

The reported transaction price per RSU is 0.0000, indicating no cash paid by Henry David Philip for the award. RSUs function as equity compensation, delivering potential future shares instead of requiring an upfront share purchase payment by the executive.