MKSI Form 144: Director Sells 4,254 Shares

MKSI notice under Form 144 reporting proposed sale of common stock.

Rhea-AI Filing Summary

MKSI notice under Form 144 reporting proposed sale of common stock. The filing lists a reported disposition of 4,254 shares with an associated dollar figure of $1,063,500.00 tied to a 02/20/2026 transaction. The filing also itemizes previously vested restricted shares from 02/15/2018 (2,383 shares) and 02/15/2024 (1,972 shares).

This submission records a routine brokered resale pathway and identifies Fidelity Brokerage Services LLC as an executing broker. The filing is administrative in nature and documents securities eligible or recently sold by the reporting person rather than company operational results.

Insights

Securities Transaction Counsel

Form 144 lists a brokered resale and specific share counts tied to restricted stock vesting dates.

The filing shows a reported disposition of 4,254 shares with $1,063,500.00 on 02/20/2026, and references restricted stock vesting of 2,383 and 1,972 shares on 02/15/2018 and 02/15/2024.

Procedurally, Form 144 notifies the market of intended resale under Rule 144 conditions. Cash‑flow treatment and whether proceeds accrue to the issuer or the selling holder are not stated in the excerpt; subsequent public disclosures or broker reports would show execution details.

Key Figures

Reported disposition: 4,254 shares Associated dollar figure: $1,063,500.00 Restricted stock vesting (2018): 2,383 shares +2 more

5 metrics

Reported disposition 4,254 shares Disposition dated 02/20/2026

Associated dollar figure $1,063,500.00 Listed alongside 02/20/2026 disposition

Restricted stock vesting (2018) 2,383 shares Vesting date 02/15/2018; labeled Compensation

Restricted stock vesting (2024) 1,972 shares Vesting date 02/15/2024; labeled Compensation

Numeric entry observed 1,393,317.05 Value shown in securities information row (exact label not provided in excerpt)

Key Terms

Form 144, Restricted Stock Vesting, Securities To Be Sold

3 terms

Form 144 regulatory

"Filer Information | 144: Filer Information"

Form 144 is a document that investors must file with the government when they plan to sell a large number of shares of a company's stock. It helps ensure transparency so everyone knows how many shares are being sold and when, which can impact the stock's price.

Restricted Stock Vesting financial

"Restricted Stock Vesting | Issuer | 02/15/2018"

Restricted stock vesting is the timetable and conditions under which shares granted to employees or insiders become fully owned and can be sold, typically requiring continued work or meeting performance goals. It matters to investors because large blocks of shares can become tradable at once, which can change share supply and price, and because vesting aligns insiders’ incentives with the company’s long‑term performance—think of it like a timed unlock that both rewards and locks in key people.

Securities To Be Sold regulatory

"144: Securities To Be Sold"

FAQ

What does MKSI's Form 144 report?

The filing reports a proposed resale of common stock including 4,254 shares tied to a 02/20/2026 transaction and dollar amount $1,063,500.00. It also lists restricted stock vesting entries dated 02/15/2018 and 02/15/2024.

Who is the broker or dealer listed on the filing for MKSI?

The filing names Fidelity Brokerage Services LLC at the address shown as the executing broker. The filing identifies the broker but does not detail execution timing or settlement counterparties.

Does this Form 144 show shares were already sold for MKSI?

The form records a reported disposition dated 02/20/2026 of 4,254 shares with $1,063,500.00. The excerpt does not provide full settlement or post‑sale holding totals.

What are the vesting entries shown on MKSI's filing?

The filing lists restricted stock vesting events: 2,383 shares with vesting date 02/15/2018 and 1,972 shares with vesting date 02/15/2024. These are disclosed as originating from compensation awards.

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Accepted by SEC EDGAR 05/11/2026 - 01:21 PM Learn about SEC filing dates

Form 144 Filer Information	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 144 NOTICE OF PROPOSED SALE OF SECURITIES PURSUANT TO RULE 144 UNDER THE SECURITIES ACT OF 1933
FORM 144

144: Filer Information

Filer CIK	0001775435
Filer CCC	XXXXXXXX
Is this a LIVE or TEST Filing?	LIVE TEST
Submission Contact Information
Name
Phone
E-Mail Address

144: Issuer Information

Name of Issuer	MKS INC
SEC File Number	000-23621
Address of Issuer	2 TECH DRIVE ANDOVER MASSACHUSETTS 01810
Phone	978-645-5500
Name of Person for Whose Account the Securities are To Be Sold	Burke Kathleen Flaherty
See the definition of "person" in paragraph (a) of Rule 144. Information is to be given not only as to the person for whose account the securities are to be sold but also as to all other persons included in that definition. In addition, information shall be given as to sales by all persons whose sales are required by paragraph (e) of Rule 144 to be aggregated with sales for the account of the person filing this notice.
Relationship to Issuer	Officer

144: Securities Information

Title of the Class of Securities To Be Sold	Name and Address of the Broker	Number of Shares or Other Units To Be Sold	Aggregate Market Value	Number of Shares or Other Units Outstanding	Approximate Date of Sale	Name the Securities Exchange
Common	Fidelity Brokerage Services LLC 900 Salem Street Smithfield RI 02917	4355	1393317.05	67544129	05/11/2026	NASDAQ

Furnish the following information with respect to the acquisition of the securities to be sold and with respect to the payment of all or any part of the purchase price or other consideration therefor:

144: Securities To Be Sold

Title of the Class	Date you Acquired	Nature of Acquisition Transaction	Name of Person from Whom Acquired	Is this a Gift?	Date Donor Acquired	Amount of Securities Acquired	Date of Payment	Nature of Payment *
Common	02/15/2018	Restricted Stock Vesting	Issuer			2383	02/15/2018	Compensation
Common	02/15/2024	Restricted Stock Vesting	Issuer			1972	02/15/2024	Compensation

* If the securities were purchased and full payment therefor was not made in cash at the time of purchase, explain in the table or in a note thereto the nature of the consideration given. If the consideration consisted of any note or other obligation, or if payment was made in installments describe the arrangement and state when the note or other obligation was discharged in full or the last installment paid.

Furnish the following information as to all securities of the issuer sold during the past 3 months by the person for whose account the securities are to be sold.

144: Securities Sold During The Past 3 Months

Name and Address of Seller	Title of Securities Sold	Date of Sale	Amount of Securities Sold	Gross Proceeds
Kathleen F. Burke 2 Tech Drive Andover MA 01810	Common	02/20/2026	4254	1063500.00

144: Remarks and Signature

Remarks
Date of Notice	05/11/2026
ATTENTION:
The person for whose account the securities to which this notice relates are to be sold hereby represents by signing this notice that he does not know any material adverse information in regard to the current and prospective operations of the Issuer of the securities to be sold which has not been publicly disclosed. If such person has adopted a written trading plan or given trading instructions to satisfy Rule 10b5-1 under the Exchange Act, by signing the form and indicating the date that the plan was adopted or the instruction given, that person makes such representation as of the plan adoption or instruction date.
Signature	/s/ Emily Navaro, as a duly authorized representative of Fidelity Brokerage Services LLC, as attorney-in-fact for Kathleen F. Burke.
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)