MKSI (NASDAQ) Rule 144: Director resale of 1,400 vested shares reported

Rhea-AI Filing Summary

MKSI filed a Rule 144 notice reporting proposed resale of 1400 shares of Common Stock tied to a Restricted Stock Vesting event on 05/11/2026. The filing lists prior dispositions in the past three months: 829 shares sold on 02/20/2026 for $205,218.95 and 341 shares sold on 03/12/2026 for $72,705.24. The brokerage intermediary shown is Fidelity Brokerage Services LLC.

Key Figures

Shares to be sold: 1400 shares Value shown: $446,586.00 Prior sale 1: 829 shares +2 more

5 metrics

Shares to be sold 1400 shares Restricted Stock Vesting on <date>05/11/2026</date>

Value shown $446,586.00 Value field on form entry dated <date>05/13/2026</date>

Prior sale 1 829 shares Sold on <date>02/20/2026</date> for <b>$205,218.95</b>

Prior sale 2 341 shares Sold on <date>03/12/2026</date> for <b>$72,705.24</b>

Brokerage intermediary Fidelity Brokerage Services LLC Listed as broker at 900 Salem Street, Smithfield, RI

Key Terms

Rule 144, Restricted Stock Vesting, Compensation, Brokerage intermediary

4 terms

Rule 144 regulatory

"144: Filer Information"

Rule 144 is a U.S. securities regulation that sets conditions under which restricted or insider-held shares can be legally resold to the public, such as required holding periods, availability of public information, limits on how much can be sold at once, and certain filing requirements. For investors it matters because it determines when previously locked-up shares can enter the market — like a release valve that can increase supply, affect share price, and signal insider intent.

Restricted Stock Vesting financial

"Common | 05/11/2026 | Restricted Stock Vesting"

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.

Compensation financial

"1400 | 05/11/2026 | Compensation"

Brokerage intermediary market

"Fidelity Brokerage Services LLC 900 Salem Street"

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

144: Issuer Information

Name of Issuer

SEC File Number

Address of Issuer

Phone

Name of Person for Whose Account the Securities are To Be Sold

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

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	1400	446586.00	67544129	05/13/2026	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	05/11/2026	Restricted Stock Vesting	Issuer			1400	05/11/2026	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
Jacqueline F. Moloney 2 Tech Drive Andover MA 01810	Common	02/20/2026	829	205218.95
Jacqueline F. Moloney 2 Tech Drive Andover MA 01810	Common	03/12/2026	341	72705.24

144: Remarks and Signature

Remarks

Date of Notice

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

ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)

FAQ

What does MKSI's Form 144 report about the securities to be sold?

The Form 144 reports an intended resale of 1400 shares of Common Stock associated with a Restricted Stock Vesting that occurred on 05/11/2026. The filing lists Fidelity Brokerage Services LLC as the broker.

Who previously sold MKSI shares in the past three months and how many?

Jacqueline F. Moloney disposed of 829 shares on 02/20/2026 and 341 shares on 03/12/2026, recorded with proceeds of $205,218.95 and $72,705.24, respectively.

What intermediary is listed on the MKSI Form 144 filing?

The filing lists Fidelity Brokerage Services LLC located at 900 Salem Street, Smithfield, RI. The broker entry is associated with the 1400 shares shown on the form dated 05/13/2026.

Does the Form 144 indicate why the 1400 shares are being sold?

Yes. The shares are linked to a Restricted Stock Vesting event and are labeled under Compensation with the vesting date of 05/11/2026, which is the source of the shares available for resale.