Mercury Systems (NASDAQ: MRCY) legal chief sells stock to cover taxes

Rhea-AI Filing Summary

MERCURY SYSTEMS INC (MRCY) reported insider activity by EVP, CLO & Corp Sec Stuart Kupinsky. He sold an aggregate 2,373 shares of common stock on August 17–18, 2026, at prices of $109.9509 and $111.3577 per share. Footnotes state these were part of a sell-to-cover program to satisfy tax withholding obligations upon vesting of stock awards, rather than discretionary sales. The filing also reports 1,233 shares of common stock held indirectly through a 401K Plan.

Insider Trade Summary

Net Seller: 2,373 shares

Net Sell 3 txns

Insider KUPINSKY STUART

Role EVP, CLO & Corp Sec

Sold 2,373 shs ($263K)

Type	Security	Shares	Price	Value
Sale	Common Stock F1, F2	1,178	$111.3577	$131K
Sale	Common Stock F1, F2	1,195	$109.9509	$131K
holding	Common Stock	--	--	--

Holdings After Transaction: Common Stock — 58,660 shares (Direct); Common Stock — 1,233 shares (Indirect, 401K Plan)

Footnotes (2)

1. F1. Represents shares sold as part of a sell-to-cover program to satisfy tax withholding obligations upon the vesting of stock awards.
2. F2. Represents the per share price attributed to sales of shares on behalf of all participants under the sell-to-cover program on the transaction date indicated.

Key Figures

Shares sold August 18, 2026: 1,178 shares Price August 18, 2026 sale: $111.3577 per share Shares sold August 17, 2026: 1,195 shares +3 more

6 metrics

Shares sold August 18, 2026 1,178 shares Common stock sold at $111.3577 per share in open-market or private transactions

Price August 18, 2026 sale $111.3577 per share Attributed per-share price for sell-to-cover sales on that transaction date

Shares sold August 17, 2026 1,195 shares Common stock sold at $109.9509 per share in open-market or private transactions

Price August 17, 2026 sale $109.9509 per share Attributed per-share price for sell-to-cover sales on that transaction date

Total shares sold 2,373 shares Aggregate net shares sold across reported transactions, primarily for tax withholding

Indirect 401K holdings 1,233 shares Common stock held indirectly through a 401K Plan as reported in holdings section

Key Terms

sell-to-cover program, tax withholding obligations, 401K Plan

3 terms

sell-to-cover program financial

"Represents shares sold as part of a sell-to-cover program to satisfy tax"

tax withholding obligations financial

"program to satisfy tax withholding obligations upon the vesting of stock awards"

401K Plan financial

"total shares following transaction 1,233.0000, nature of ownership 401K Plan"

A 401(k) plan is an employer-sponsored retirement savings account that lets workers set aside part of their paycheck into investments, often with tax breaks and sometimes with matching contributions from the employer. Think of it as a workplace piggy bank that grows through employee contributions, optional company top-ups, and market returns; it matters to investors because it shapes household retirement security, drives large flows of money into public markets, and affects a company’s compensation costs and ability to attract and keep talent.

FAQ

What insider transactions were reported for MRCY EVP Stuart Kupinsky in this Form 4?

Stuart Kupinsky reported selling 2,373 shares of MERCURY SYSTEMS INC (MRCY) common stock on August 17–18, 2026. The sales were executed under a sell-to-cover program to satisfy tax withholding obligations when stock awards vested, according to the filing’s footnotes.

At what prices did Stuart Kupinsky’s recent MRCY share sales occur?

The reported MRCY share sales occurred at per-share prices of $109.9509 and $111.3577. These prices represent the amounts attributed to shares sold on behalf of all participants under the sell-to-cover program on each respective transaction date, as described in the footnotes.

How many MRCY shares did Stuart Kupinsky sell in total in this filing?

The Form 4 reports that Stuart Kupinsky sold a total of 2,373 shares of MERCURY SYSTEMS INC (MRCY) common stock. This consists of 1,195 shares sold on August 17, 2026, and 1,178 shares sold on August 18, 2026, under a sell-to-cover program.

Were Stuart Kupinsky’s MRCY sales made under a Rule 10b5-1 trading plan?

The filing’s Rule 10b5-1 checkbox is not marked as a plan transaction, and no footnote describes a Rule 10b5-1 arrangement. Instead, the footnotes describe the sales as part of a sell-to-cover program for tax withholding upon stock award vesting.

What MRCY share holdings does Stuart Kupinsky report after these transactions?

The Form 4 shows 1,233 shares of MERCURY SYSTEMS INC (MRCY) common stock held indirectly through a 401K Plan. The filing does not state the total number of shares, if any, still held directly following the reported sell-to-cover transactions.

What is the nature of the sell-to-cover program mentioned in the MRCY Form 4?

The footnotes explain that the reported sales represent shares sold under a sell-to-cover program to satisfy tax withholding obligations when stock awards vest. The per-share prices reflect amounts attributed to sales on behalf of all participants in that program on each date.

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

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Form 4 Insider Transactions: What Each Field Means →

Available on EDGAR 08/19/2026 - 06:27 PM Accepted by SEC EDGAR 08/19/2026 - 06:26 PM 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^*

KUPINSKY STUART

(Last) (First) (Middle)

50 MINUTEMAN ROAD

(Street)

ANDOVER MASSACHUSETTS 01810

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
MERCURY SYSTEMS INC [ MRCY ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	EVP, CLO & Corp Sec

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
08/17/2026

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	08/17/2026		S		1,195(1)	D	$109.9509(2)	59,838	D
Common Stock	08/18/2026		S		1,178(1)	D	$111.3577(2)	58,660	D
Common Stock								1,233	I	401K Plan

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:

1. Represents shares sold as part of a sell-to-cover program to satisfy tax withholding obligations upon the vesting of stock awards.

2. Represents the per share price attributed to sales of shares on behalf of all participants under the sell-to-cover program on the transaction date indicated.

	/s/ Douglas Munro, attorney-in-fact	08/19/2026
	** 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)