MKS Inc director sells 1,350 shares of stock

MKS Inc director Peter Cannone III reported an open-market sale of 1,350 shares of Common Stock on May 18, 2026 at a price of $303.4001 per share.

Rhea-AI Filing Summary

MKS Inc director Peter Cannone III reported an open-market sale of 1,350 shares of Common Stock on May 18, 2026 at a price of $303.4001 per share. After this transaction, he directly holds 7,794.039 shares, indicating he retains a meaningful ongoing equity stake in the company.

Insights

Equity analyst

Director executed a moderate open-market sale while retaining a sizable stake.

Director Peter Cannone III sold 1,350 shares of MKS Inc Common Stock in an open-market transaction at $303.4001 per share. The Form 4 characterizes this as an open-market sale, which is typically a discretionary transaction.

Following the sale, he directly holds 7,794.039 shares. With no derivative positions listed in this filing and no footnotes indicating a trading plan or indirect ownership structures, the transaction appears straightforward. On its own, this kind of sale is usually viewed as routine portfolio management rather than a thesis-changing event.

Insider Trade Summary

Net Seller: 1,350 shares

Net Sell 1 txn

Insider CANNONE PETER III

Role Director

Sold 1,350 shs ($410K)

Type	Security	Shares	Price	Value
Sale	Common Stock	1,350	$303.4001	$410K

Holdings After Transaction: Common Stock — 7,794.039 shares (Direct)

Key Figures

Shares sold: 1,350 shares Sale price: $303.4001 per share Shares held after transaction: 7,794.039 shares +1 more

4 metrics

Shares sold 1,350 shares Open-market sale on May 18, 2026

Sale price $303.4001 per share Price for Common Stock sale

Shares held after transaction 7,794.039 shares Direct holdings following sale

Net shares sold 1,350 shares Net sell direction in transaction summary

Key Terms

Common Stock, open-market sale, Form 4, transaction code "S"

4 terms

Common Stock financial

"security_title: "Common Stock""

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

"transaction_action: "open-market sale""

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.

Form 4 regulatory

"INSIDER FILING DATA (Form 4)"

Form 4 is a official document that company insiders, such as executives or major shareholders, file with regulators whenever they buy or sell company shares. It provides transparency about how those with inside knowledge are trading, helping investors see if insiders are confident in the company's prospects or may be selling for personal reasons. This information can influence investor decisions by revealing insiders' perspectives on the company's value.

transaction code "S" financial

"transaction_code_description: "Sale in open market or private transaction""

FAQ

What insider transaction did MKS Inc (MKSI) disclose for Peter Cannone III?

MKS Inc reported that director Peter Cannone III sold 1,350 shares of Common Stock. The transaction was an open-market sale at a price of $303.4001 per share, as disclosed in a Form 4 insider trading report.

At what price did the MKS Inc (MKSI) director sell his shares?

The director’s shares were sold at $303.4001 per share. This price reflects the execution level for the 1,350-share open-market transaction reported in the Form 4 filing for MKS Inc.

How many MKS Inc (MKSI) shares does Peter Cannone III hold after the sale?

After the reported sale, Peter Cannone III directly holds 7,794.039 MKS Inc shares. This remaining position shows he continues to maintain a meaningful ownership stake in the company following the 1,350-share disposition.

Was the MKS Inc (MKSI) insider transaction an open-market sale or another type?

The insider transaction was an open-market sale of Common Stock. The Form 4 identifies the transaction code as “S” and describes it as a sale in open market or private transaction, confirming it was not a grant, gift, or tax withholding.

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

The Form 4 does not list any derivative securities for the director. The derivativeSummary is empty, indicating no options, warrants, or other derivatives are reported alongside this 1,350-share open-market sale.

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

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Accepted by SEC EDGAR 05/19/2026 - 10:46 AM Learn about SEC filing dates

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).

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^*

CANNONE PETER III

(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)

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
05/18/2026

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	05/18/2026		S		1,350	D	$303.4001	7,794.039	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:

	/s/ James Kruger, attorney-in-fact	05/19/2026
	** 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)