MKS Inc. (MKSI) EVP, GC & Secretary awarded 7,008.628 performance RSUs

Rhea-AI Filing Summary

MKS Inc. executive Kathleen Flaherty Burke, EVP, GC & Secretary, reported an equity award on a Form 4. On February 8, 2026, she was granted 7,008.628 restricted stock units (RSUs), each representing one share of MKS common stock. These performance-based RSUs vest in three equal annual installments beginning on February 15, 2026, with vesting on the next business day if that date is not a business day. After this grant, she directly holds 24,007.365 derivative securities in the form of RSUs.

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^*

Burke Kathleen Flaherty

(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, GC & Secretary

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		7,008.628		(2)	(2)	Common Stock	7,008.628	(1)	24,007.365	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.
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FAQ

What insider transaction did MKS Inc. (MKSI) report for February 8, 2026?

MKS Inc. reported an equity award to executive Kathleen Flaherty Burke on February 8, 2026. She received 7,008.628 restricted stock units (RSUs), a form of stock-based compensation, rather than buying or selling existing shares in the open market.

How many restricted stock units did the MKS Inc. EVP receive in this Form 4?

The EVP, GC & Secretary of MKS Inc., Kathleen Flaherty Burke, received 7,008.628 restricted stock units. Each RSU represents the contingent right to receive one share of MKS common stock, making this a sizeable performance-based equity grant tied to future vesting conditions.

What does each RSU represent in the MKS Inc. Form 4 filing?

Each RSU reported in the MKS Inc. filing represents the contingent right to receive one share of MKS common stock. This means the executive will receive actual shares only as the restricted stock units vest over time, subject to the stated vesting conditions.

What is the vesting schedule for the 7,008.628 RSUs granted by MKS Inc.?

The 7,008.628 RSUs vest in three equal annual installments beginning on February 15, 2026. If February 15 in any vesting year is not a business day, vesting occurs on the next business day, subject to the previously determined performance criteria being satisfied.

Were performance conditions attached to the RSUs granted by MKS Inc. to its EVP?

Yes. The RSUs were subject to performance criteria, with achievement determined on February 8, 2026. After that determination, the RSUs vest in three equal annual installments, aligning the executive’s equity compensation with previously assessed performance outcomes at the company.

How many RSUs does the MKS Inc. executive beneficially own after this transaction?

Following this grant, Kathleen Flaherty Burke beneficially owns 24,007.365 derivative securities in the form of RSUs. These are held directly and represent potential future shares of MKS common stock, subject to the applicable vesting schedules and conditions described in the filing.