MKS Inc (NASDAQ: MKSI) EVP sells 2,500 shares under Rule 10b5-1 plan

Rhea-AI Filing Summary

MKS Inc executive Henry David Philip reported an open-market sale of 2,500 shares of Common Stock at $330.50 per share. After the transaction, he directly holds 16,341.368 shares. The sale was carried out under a pre-arranged Rule 10b5-1 trading plan adopted on February 24, 2026.

Insider Trade Summary 10b5-1

Net Seller: 2,500 shares ($826,250)

Net Sell 1 txn

Insider Henry David Philip

Role EVP, Global Str Mktg & GM, MSD

Sold 2,500 shs ($826K)

Type	Security	Shares	Price	Value
Sale	Common Stock	2,500	$330.50	$826K

Holdings After Transaction: Common Stock — 16,341.368 shares (Direct, null)

Footnotes (1)

1. [object Object]

Key Figures

Shares sold: 2,500 shares Sale price per share: $330.50 per share Shares held after transaction: 16,341.368 shares +1 more

4 metrics

Shares sold 2,500 shares Open-market sale of Common Stock

Sale price per share $330.50 per share Price for the 2,500 shares sold

Shares held after transaction 16,341.368 shares Direct ownership following the sale

Trading plan adoption date February 24, 2026 Rule 10b5-1 plan used for the sale

Key Terms

Common Stock, open-market sale, Rule 10b5-1 trading plan

3 terms

Common Stock financial

"reported an open-market sale of 2,500 shares of Common Stock at $330.50 per share"

Common stock represents ownership shares in a company, giving investors a stake in its success and a say in important decisions through voting rights. It is the most common type of stock traded on markets and can provide income through dividends, as well as potential for value growth. For investors, holding common stock means sharing in the company’s profits and risks.

open-market sale financial

"reported an open-market sale of 2,500 shares of Common Stock"

An open-market sale is when a shareholder sells existing shares directly on a public exchange to any willing buyer, rather than through a private deal. Think of it like putting goods on a busy market stall where price is set by supply and demand; for investors it matters because such sales increase available supply, can put short-term downward pressure on the stock price, and signal changes in liquidity or investor confidence.

Rule 10b5-1 trading plan regulatory

"The sale was carried out under a pre-arranged Rule 10b5-1 trading plan adopted on February 24, 2026"

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.

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Form 4 Insider Transactions: What Each Field Means →

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^*

Henry David Philip

(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, Global Str Mktg & GM, MSD

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
05/26/2026

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	05/26/2026		S(1)		2,500	D	$330.5	16,341.368	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 24, 2026.

	/s/ James Kruger, attorney-in-fact	05/27/2026
	** 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)

FAQ

What insider transaction did MKS Inc (MKSI) report for Henry David Philip?

MKS Inc reported that executive Henry David Philip sold 2,500 shares of Common Stock in an open-market transaction at $330.50 per share, as disclosed in a Form 4 insider trading report.

At what price did Henry David Philip sell MKS Inc (MKSI) shares?

Henry David Philip sold 2,500 MKS Inc Common Stock shares at $330.50 per share. This was an open-market transaction reported on Form 4 and executed under a pre-arranged Rule 10b5-1 trading plan.

How many MKS Inc (MKSI) shares does Henry David Philip hold after the sale?

Following the reported sale, Henry David Philip directly holds 16,341.368 shares of MKS Inc Common Stock. This post-transaction ownership figure is disclosed in the Form 4 filing as his direct holdings.

Was the MKS Inc (MKSI) insider sale made under a Rule 10b5-1 plan?

Yes. The Form 4 footnote explains the sale was effected pursuant to a Rule 10b5-1 trading plan adopted by Henry David Philip on February 24, 2026, indicating the transaction was pre-arranged.

What type of transaction did MKS Inc (MKSI) report in this Form 4?

The Form 4 reports a non-derivative open-market sale of Common Stock by executive Henry David Philip. He sold 2,500 shares at $330.50 per share and continues to hold 16,341.368 shares directly afterward.