[Form 4] MERCURY SYSTEMS INC Insider Trading Activity

Rhea-AI Filing Summary

Mercury Systems (MRCY): Form 4 insider transaction. JANA Partners Management, LP reported a sale of 1,000,000 shares of common stock on 11/06/2025, coded “S” (sale), at a price of $75.45 per share. Following the transaction, JANA reported 4,966,675 shares beneficially owned on an indirect basis.

The filing notes the trade was made to rebalance holdings across funds and accounts managed by JANA. The firm disclaims beneficial ownership beyond any pecuniary interest. JANA may be deemed a director by deputization because its managing partner, Scott Ostfeld, serves on Mercury’s board.

Insights

Equity Ownership and Governance Analyst

Large insider-affiliated sale by a board‑linked holder; stake remains sizable; governance link continues.

On 11/06/2025, an entity affiliated with **JANA Partners Management, LP** reported an open‑market sale (code S) of 1,000,000 shares of **Mercury Systems, Inc.** at $75.45 per share. After the transaction, 4,966,675 shares are reported as indirectly beneficially owned. The filing describes JANA as a private money manager and notes the sale was for rebalancing across managed accounts.

JANA may be deemed a director by deputization, as a JANA managing partner currently serves on Mercury’s board. That linkage remains, indicating continued governance influence despite the partial reduction. The form indicates indirect ownership, which matters because the holdings are across accounts managed by JANA, not necessarily held directly.

Key items to watch: any further Form 4 sales or purchases, any Schedule 13D/G amendments reflecting ownership changes, and any updates to board representation. Subsequent filings in the coming weeks could clarify whether this was a one‑time rebalance or part of a broader adjustment.

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
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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)
11/06/2025

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	11/06/2025		S(1)		1,000,000	D	$75.45	4,966,675	I	See footnote(2)

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. The transaction reported herein was effected for the purpose of rebalancing the holdings of funds and accounts managed by JANA (as defined below).

2. JANA Partners Management, LP ("JANA" or the "Reporting Person") 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 Scott Ostfeld, a Managing Partner and Portfolio Manager 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	11/10/2025
	** Signature of Reporting Person	Date
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