Mercury Systems (NASDAQ: MRCY) holder plans 1,178-share sale, including tax-cover stock

Rhea-AI Filing Summary

MERCURY SYSTEMS INC (MRCY) is the issuer for a notice of proposed sale of common stock under Rule 144 filed for the account of Stuart Kupinsky. The filing lists a proposed sale of 1,178 common shares through Fidelity Brokerage Services LLC and notes that the sale includes shares needed to cover a tax obligation from a vested equity award. It also reports that 1,195 common shares were sold in the prior three months.

Key Figures

Proposed shares to be sold: 1,178 shares Proposed aggregate value: $131,179.37 Prior shares sold: 1,195 shares +2 more

5 metrics

Proposed shares to be sold 1,178 shares Common stock proposed for sale under Rule 144

Proposed aggregate value $131,179.37 Aggregate market value for 1,178 shares

Prior shares sold 1,195 shares Common stock sold during the past 3 months

Prior sale aggregate value $131,391.33 Aggregate value of 1,195 shares sold on 08/17/2026

Date of Notice 08/18/2026 Filing date of the Form 144 notice

Key Terms

Rule 144, Restricted Stock Vesting, vested equity award, attorney-in-fact

4 terms

Rule 144 regulatory

"See the definition of "person" in paragraph (a) of Rule 144."

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 | 08/17/2026 | Restricted Stock Vesting | Issuer"

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.

vested equity award financial

"resulting from the settlement of a vested equity award distribution."

attorney-in-fact regulatory

"as attorney-in-fact for Stuart Kupinsky"

An attorney-in-fact is the person or entity given legal authority through a power of attorney to act on behalf of another for specific tasks, such as signing documents, voting shares, or handling transactions. For investors, this matters because it lets a trusted representative make timely decisions or complete paperwork when the owner cannot, much like handing keys to someone to run errands on your behalf—so checks on scope and limits of that authority are important.

FAQ

What does this Form 144 filing mean for MERCURY SYSTEMS INC (MRCY)?

The filing records a planned Rule 144 sale of 1,178 common shares of MERCURY SYSTEMS INC for the account of Stuart Kupinsky. It is a disclosure of a potential resale of shares, including amounts related to tax obligations from vested equity awards.

How many MRCY shares are proposed to be sold under this Form 144?

The notice covers a proposed sale of 1,178 common shares of MERCURY SYSTEMS INC. These shares are to be sold through Fidelity Brokerage Services LLC and are linked to the settlement of a vested equity award and related tax obligations.

What prior sales does the Form 144 disclose for MRCY stock?

The Form 144 discloses that on 08/17/2026, 1,195 common shares of MERCURY SYSTEMS INC were sold for an aggregate value of $131,391.33. These sales are reported as occurring within the three months preceding the notice.

What is the stated value of the proposed MRCY share sale?

The proposed sale of 1,178 MRCY common shares has an aggregate value listed as $131,179.37. This value appears in the securities information section associated with the planned Rule 144 transaction on the NASDAQ market.

Why does the Form 144 mention tax obligations for MRCY shares?

The remarks state the sale includes an amount needed to cover a tax obligation from settling a vested equity award. This indicates part of the 1,178-share sale is intended to satisfy taxes arising from restricted stock vesting compensation.

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

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Available on EDGAR 08/18/2026 - 03:44 PM Accepted by SEC EDGAR 08/18/2026 - 03:43 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	0001289593
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	MERCURY SYSTEMS INC
SEC File Number	001-41194
Address of Issuer	50 MINUTEMAN ROAD ANDOVER MASSACHUSETTS 01810
Phone	9782561300
Name of Person for Whose Account the Securities are To Be Sold	KUPINSKY STUART
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	1178	131179.37	60043283	08/18/2026	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	08/17/2026	Restricted Stock Vesting	Issuer			1178	08/17/2026	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
Stuart Kupinsky 50 MINUTEMAN ROAD ANDOVER MA 01810	Common	08/17/2026	1195	131391.33

144: Remarks and Signature

Remarks	Sale includes an amount necessary to cover a tax obligation resulting from the settlement of a vested equity award distribution.
Date of Notice	08/18/2026
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/ Daniel Tucci, as a duly authorized representative of Fidelity Brokerage Services LLC, as attorney-in-fact for Stuart Kupinsky
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)