MKS Inc (MKSI) EVP sells stock under Rule 10b5-1 trading plan

Rhea-AI Filing Summary

MKS Inc executive John Edward Williams, EVP & GM, PSD, reported selling 457 shares of Common Stock on August 3, 2026 at $288.31 per share in a sale described as an open market or private transaction. Following this trade, he directly held 4,097.844 shares. The sale was effected pursuant to a Rule 10b5-1 trading plan adopted on March 5, 2026.

Insider Trade Summary 10b5-1

Net Seller: 457 shares

Net Sell 1 txn

Insider Williams John Edward

Role EVP & GM, PSD

Sold 457 shs ($132K)

Type	Security	Shares	Price	Value
Sale	Common Stock F1	457	$288.31	$132K

Holdings After Transaction: Common Stock — 4,097.844 shares (Direct)

Footnotes (1)

1. F1. This transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on March 5, 2026.

Key Figures

Shares sold: 457 shares Sale price per share: $288.31 per share Shares held after transaction: 4,097.844 shares

3 metrics

Shares sold 457 shares Non-derivative Common Stock sale on August 3, 2026

Sale price per share $288.31 per share Price for the 457-share Common Stock sale

Shares held after transaction 4,097.844 shares Directly held Common Stock following the reported sale

Key Terms

Rule 10b5-1 trading plan, open market or private transaction, non-derivative

3 terms

Rule 10b5-1 trading plan regulatory

"The sale was effected pursuant to a Rule 10b5-1 trading plan"

A Rule 10b5-1 trading plan is a pre-arranged schedule that allows company insiders to buy or sell stock at specific times, even if they have inside information. It helps prevent accusations of unfair trading by making these transactions look planned and transparent, rather than sneaky or illegal.

open market or private transaction financial

"coded “S” and described as a sale in an open market or private transaction"

non-derivative financial

"The Form 4 transaction involves only non-derivative Common Stock"

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Form 4 Insider Transactions: What Each Field Means →

Available on EDGAR 08/04/2026 - 12:22 PM Accepted by SEC EDGAR 08/04/2026 - 12:21 PM Learn about SEC filing dates

FAQ

Who is the insider trading in MKS Inc (MKSI) in this Form 4?

The filer is John Edward Williams, who serves as EVP & GM, PSD at MKS Inc. He reported one transaction in Common Stock, reflecting activity in his directly held shares as an executive officer of the company.

How many MKS Inc (MKSI) shares did John Edward Williams sell and at what price?

John Edward Williams sold 457 shares of MKS Inc Common Stock at $288.31 per share. The sale occurred on August 3, 2026 and is reported as a non-derivative transaction in Common Stock on this Form 4.

What are John Edward Williams’ MKS Inc (MKSI) holdings after this reported sale?

After the reported sale, John Edward Williams directly held 4,097.844 shares of MKS Inc Common Stock. This figure reflects his position immediately following the August 3, 2026 transaction disclosed in the Form 4 filing.

Was the MKS Inc (MKSI) share sale by John Edward Williams under a Rule 10b5-1 plan?

Yes. The sale was effected pursuant to a Rule 10b5-1 trading plan adopted by John Edward Williams on March 5, 2026, according to the footnote accompanying the reported transaction in the Form 4.

What type of transaction is reported for MKS Inc (MKSI) in this Form 4?

The Form 4 reports a sale of Common Stock as a non-derivative transaction, coded “S” and described as a sale in an open market or private transaction. It involved 457 shares sold at $288.31 per share.

Does the MKS Inc (MKSI) Form 4 show any derivative securities transactions?

No. The Form 4 transaction involves only non-derivative Common Stock. The derivative securities section is empty, and the transaction summary shows zero derivative transactions or option exercises reported for this filing.

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^*

Williams John Edward

(Last) (First) (Middle)

C/O MKS INC.

2 TECH DRIVE

(Street)

ANDOVER MASSACHUSETTS 01810

(City) (State) (Zip)

UNITED STATES

(Country)

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 & GM, PSD

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
08/03/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

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	08/03/2026		S(1)		457	D	$288.31	4,097.844	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 5, 2026.

	/s/ James Kruger, attorney-in-fact	08/04/2026
	** 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.
* Form 4: SEC 1474 (03-26)