[Form 4] MERCURY SYSTEMS INC Insider Trading Activity

Mercury Systems (MRCY) reported a director’s acquisition of 2,362 deferred stock units (recorded as common stock with footnote) at $0 on 10/22/2025.

Rhea-AI Filing Summary

Mercury Systems (MRCY) reported a director’s acquisition of 2,362 deferred stock units (recorded as common stock with footnote) at $0 on 10/22/2025. Following the transaction, the director beneficially owns 7,815 shares directly.

The filing notes these are deferred stock units (DSUs) that vest on the earlier of the first anniversary of the grant date or the next annual meeting of shareholders. Vested DSUs convert into common stock only when the director ceases to serve on the Board.

Insider Trade Summary

Grant/Award: 2,362 shares

Grant/Award 1 txn

Insider BUA JEAN A

Role Director

Type	Security	Shares	Price	Value
Grant/Award	Common Stock	2,362	$0.00	$0.00

Holdings After Transaction: Common Stock — 7,815 shares (Direct)

Footnotes (1)

1. F1. Represents deferred stock units (DSUs) that vest on the earlier of the first anniversary of the grant date and the next annual meeting of shareholders. Vested DSUs do not convert into shares of common stock until the date on which the reporting person ceases to be a member of our Board of Directors.

FAQ

What did Mercury Systems (MRCY) disclose in this Form 4?

A director acquired 2,362 deferred stock units at $0 on 10/22/2025, bringing direct beneficial ownership to 7,815 shares.

How do the DSUs for MRCY’s director vest?

They vest on the earlier of the first anniversary of the grant date or the next annual meeting of shareholders.

When do the DSUs convert into common stock for MRCY?

Vested DSUs convert into shares only when the director ceases to be a member of the Board of Directors.

What was the transaction price reported for the MRCY DSUs?

The transaction was reported at $0.

What is the director’s ownership after the transaction at MRCY?

Direct beneficial ownership is 7,815 shares after the reported transaction.

What is the transaction date on the MRCY Form 4?

The transaction date is 10/22/2025.

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Accepted by SEC EDGAR 10/24/2025 - 04:55 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^*

BUA JEAN A

(Last) (First) (Middle)

50 MINUTEMAN ROAD

(Street)

ANDOVER MA 01810

(City) (State) (Zip)

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

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

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
10/22/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

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	10/22/2025		A		2,362(1)	A	$0	7,815	D

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 deferred stock units (DSUs) that vest on the earlier of the first anniversary of the grant date and the next annual meeting of shareholders. Vested DSUs do not convert into shares of common stock until the date on which the reporting person ceases to be a member of our Board of Directors.

	/s/ Douglas Munro, attorney-in-fact	10/24/2025
	** 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.