Mercury Systems EVP granted 5,619 RSUs

Amended Form 4 for MRCY adds a three-year vesting grant of 5,619 restricted stock units to the company’s chief legal officer.

This filing corrects an earlier one, and you can read the original Form 4 if you want to see what changed.

Rhea-AI Filing Summary

MERCURY SYSTEMS INC (symbol: MRCY) is the issuer of record for a Form 4/A filing submitted to the SEC. KUPINSKY STUART reported acquisition or exercise transactions in this Form 4 filing.

MERCURY SYSTEMS INC (MRCY) reported an amended insider filing for executive vice president, chief legal officer and corporate secretary Stuart Kupinsky. On August 17, 2026, he received a grant of 5,619 shares of common stock in the form of restricted stock units that vest in equal annual installments over three years. After this grant, he held 65,457 shares of common stock directly and 1,233 shares indirectly through a 401(k) plan. No transactions are reported under a Rule 10b5-1 trading plan.

Insider Trade Summary

Grant/Award: 5,619 shares

Grant/Award 2 txns

Insider KUPINSKY STUART

Role EVP, CLO & Corp Sec

Type	Security	Shares	Price	Value
Grant/Award	Common Stock F1	5,619	$0.00	$0.00
holding	Common Stock	--	--	--

Holdings After Transaction: Common Stock — 65,457 shares (Direct); Common Stock — 1,233 shares (Indirect, 401K Plan)

Footnotes (1)

1. F1. Represents restricted stock units that vest in equal annual increments over the three-year period following the grant date.

Key Figures

Restricted stock units granted: 5,619 shares Direct common shares after grant: 65,457 shares Indirect 401(k) holdings: 1,233 shares +1 more

4 metrics

Restricted stock units granted 5,619 shares Equity award to Stuart Kupinsky on August 17, 2026

Direct common shares after grant 65,457 shares Direct holdings of Stuart Kupinsky following the August 17, 2026 grant

Indirect 401(k) holdings 1,233 shares Common stock held indirectly through a 401(k) plan after the grant

Vesting period 3 years Restricted stock units vest in equal annual increments over three years after the grant date

Key Terms

restricted stock units

1 terms

restricted stock units financial

"Represents restricted stock units that vest in equal annual increments over the three-year period"

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What change does the amended Form 4 report for MRCY insider Stuart Kupinsky?

The amendment adds a previously omitted grant of 5,619 restricted stock units of Mercury Systems common stock to Stuart Kupinsky on August 17, 2026.

How many MRCY shares were granted to the officer on August 17, 2026?

On August 17, 2026, Stuart Kupinsky received a grant of 5,619 restricted stock units, each representing one share of Mercury Systems common stock, subject to vesting.

What is the vesting schedule for the 5,619 MRCY restricted stock units?

The 5,619 restricted stock units vest in equal annual increments over three years following the August 17, 2026 grant date.

How many MRCY shares does the reporting person hold after this grant?

After the grant, Stuart Kupinsky held 65,457 shares of Mercury Systems common stock directly and 1,233 shares indirectly through a 401(k) plan.

Was the MRCY insider grant made under a Rule 10b5-1 trading plan?

No. The filing indicates that no Rule 10b5-1 trading plan applies to the reported transactions.

Does the amended MRCY Form 4 report any stock sales by the officer?

No. The amended filing reports an equity grant and updated holdings but no sales of Mercury Systems common stock by the officer.

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

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Available on EDGAR 09/15/2026 - 06:09 PM Accepted by SEC EDGAR 09/15/2026 - 06:08 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)
08/18/2026

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		A		5,619(1)	A	$0	65,457	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 restricted stock units that vest in equal annual increments over the three-year period following the grant date.

Remarks:

This amendment is being filed to correct the inadvertent omission of the grant of restricted stock units to the reporting person on August 17, 2026.

	/s/ Douglas Munro, attorney-in-fact	09/15/2026
	** 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)