[Form 4] MERCURY SYSTEMS INC Insider Trading Activity

Rhea-AI Filing Summary

Mercury Systems (MRCY): JANA Partners Management, LP filed a Form 4 reporting the acquisition of 2,362 shares of common stock on 10/22/2025 at a price of $0, recorded as director compensation via deferred stock units (DSUs). Following the transaction, 5,966,675 shares are reported as indirectly beneficially owned. The DSUs vest on the earlier of the first anniversary of the grant date or the next annual meeting of shareholders, and convert into common stock only when Scott Ostfeld ceases to serve on the board.

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

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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^*

JANA Partners Management, LP

(Last) (First) (Middle)

888 SEVENTH AVENUE

24TH FLOOR

(Street)

NEW YORK NY 10106

(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)	X	Other (specify below)
			See Remarks

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, par value $0.01 per share	10/22/2025		A		2,362(1)	A	$0	5,966,675	I	See footnotes(2)(3)

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 Scott Ostfeld ("Mr. Ostfeld"), the Managing Partner of JANA Partners Management, LP ("JANA" or the "Reporting Person") ceases to be a member of the Issuer's board of directors.

2. Mr. Ostfeld has assigned all rights to any shares issuable pursuant to the grant to the Reporting Person. Pursuant to the assignment, settlement of the award on vesting will be made to the Reporting Person.

3. JANA is a private money management firm which beneficially owns the securities reported herein through various accounts under its management and control. JANA Partners Management GP, LLC (the "GP") is the general partner of JANA. Barry Rosenstein is the Founder of the GP and JANA. JANA, the GP and Barry Rosenstein disclaim any beneficial ownership of any of the Issuer's securities reported herein except to the extent of their pecuniary interest therein, if any.

Remarks:

The Reporting Person may be deemed to be a director by deputization for purposes of Section 16 under the Securities Exchange Act of 1934 by virtue of the fact that Mr. Ostfeld, a Managing Partner and Portfolio Manager of of the Reporting Person, currently serves on the board of directors of the Issuer.

	/s/ JANA Partners Management, LP, by Jennifer Fanjiang, Partner, Chief Legal Officer and Chief Compliance Officer	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.

FAQ

What did JANA Partners report on Form 4 for MRCY?

JANA reported acquiring 2,362 shares on 10/22/2025 at $0 via deferred stock units as director compensation.

How many MRCY shares does JANA report beneficially owning after the transaction?

The filing lists 5,966,675 shares as indirectly beneficially owned following the reported transaction.

When do the reported DSUs for MRCY vest and convert?

The DSUs vest on the earlier of the first anniversary of the grant date or the next annual meeting, and convert only when Mr. Ostfeld leaves the board.

Who is the individual associated with JANA in this MRCY filing?

The filing references Scott Ostfeld, a Managing Partner of JANA, who serves on Mercury Systems’ board.

What was the transaction price for the acquired MRCY shares?

The shares were acquired at $0, reflecting a grant of DSUs as compensation.

How is ownership characterized in the MRCY Form 4?

Ownership is listed as Indirect (I), with nature described in the footnotes regarding DSUs assigned to JANA.