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MKS Inc (MKSI) accounting chief sells 2,434 shares under Rule 10b5-1 plan

Filing Impact
(Very High)
Filing Sentiment
(Negative)
Form Type
4

Rhea-AI Filing Summary

MKS Inc senior vice president and chief accounting officer Michelle M. McCarthy sold 2,434 shares of common stock in an open-market transaction at $315.23 per share. After the sale, she directly holds 1.5490 shares. The transaction was carried out under a pre-arranged Rule 10b5-1 trading plan adopted on March 5, 2026, indicating it was scheduled in advance.

Positive

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Negative

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Insider McCarthy Michelle M
Role SVP & Chief Accounting Officer
Sold 2,434 shs ($767K)
Type Security Shares Price Value
Sale Common Stock 2,434 $315.23 $767K
Holdings After Transaction: Common Stock — 1.549 shares (Direct, null)
Footnotes (1)
  1. [object Object]
Shares sold 2,434 shares Open-market sale on June 5, 2026
Sale price $315.23 per share Average sale price for common stock
Shares owned after transaction 1.5490 shares Direct holdings following the sale
Rule 10b5-1 plan adoption date March 5, 2026 Plan governing the reported sale
Rule 10b5-1 trading plan regulatory
"This transaction was effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person"
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 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.
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Form 4 Insider Transactions: What Each Field Means →
SEC Form 4
FORM 4UNITED 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*
McCarthy Michelle M
(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)
Director10% Owner
XOfficer (give title below)Other (specify below)
SVP & Chief Accounting Officer
2a. Foreign Trading Symbol
3. Date of Earliest Transaction (Month/Day/Year)
06/05/2026		6. Individual or Joint/Group Filing (Check Applicable Line)
XForm 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)
CodeVAmount(A) or (D)Price
Common Stock06/05/2026S(1)2,434D$315.231.549D
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)
CodeV(A)(D)Date ExercisableExpiration DateTitleAmount 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-fact06/08/2026
** Signature of Reporting PersonDate
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)

Source: View Original Filing on SEC EDGAR

FAQ

What insider transaction did MKS Inc (MKSI) report for Michelle McCarthy?

MKS Inc reported that Michelle M. McCarthy, SVP and Chief Accounting Officer, sold 2,434 shares of common stock. The open-market sale occurred at a price of $315.23 per share under a pre-arranged Rule 10b5-1 trading plan.

At what price were the MKS Inc (MKSI) shares sold in this Form 4?

The reported shares were sold at an average price of $315.23 per share. This reflects an open-market transaction in MKS Inc common stock executed as part of a Rule 10b5-1 trading plan adopted by the reporting officer.

How many MKS Inc (MKSI) shares does Michelle McCarthy hold after the sale?

Following the reported sale, Michelle M. McCarthy directly holds 1.5490 shares of MKS Inc common stock. This figure reflects her remaining direct ownership position as disclosed in the Form 4 after the 2,434-share open-market sale.

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

Yes. The filing states the transaction was executed pursuant to a Rule 10b5-1 trading plan adopted on March 5, 2026. Such plans allow insiders to schedule trades in advance, reducing the significance of trade timing information.

What role does Michelle McCarthy hold at MKS Inc (MKSI)?

Michelle M. McCarthy serves as senior vice president and chief accounting officer at MKS Inc. Her Form 4 filing reports an open-market sale of 2,434 shares of common stock at $315.23 per share, executed under a Rule 10b5-1 trading plan.