[Form 4] Mercury Systems Inc. Insider Trading Activity

Rhea-AI Filing Summary

JANA Partners Management, LP reported on Form 4 that it disposed of 797,000 shares of Mercury Systems Inc. (MRCY) on 08/13/2025 at a reported price of $65.42 per share. After the sale, JANA beneficially owned 5,964,313 shares, held indirectly through funds and accounts it manages. The filing states the transactions were made to rebalance holdings across JANA-managed funds and accounts. The report notes that JANA is a private money management firm and explains the general partner and founder relationships, and it clarifies that any director status is by deputization because a JANA managing partner, Scott Ostfeld, serves on the issuer’s board.

Key facts: sale of 797,000 shares at $65.42; post-transaction indirect beneficial ownership 5,964,313 shares; purpose cited as portfolio rebalancing.

Insights

Securities Analyst

TL;DR: A significant block sale by an institutional holder reduced its indirect stake; labeled as portfolio rebalancing, not an insider-driven sale.

JANA Partners Management, LP reported a disposition of 797,000 MRCY shares at $65.42, leaving 5,964,313 shares beneficially owned indirectly. The filing explicitly attributes the trade to rebalancing across managed funds and clarifies the reporting structure and relationships. From a securities-analytic perspective, the sale is material relative to the holder’s prior position (roughly a double-digit percent reduction of the pre-sale stake based on the reported post-sale holding), which could affect near-term supply in the market. The filing contains no disclosure of plans to sell additional shares or other strategic actions and includes standard disclaimers about beneficial ownership limits.

Corporate Governance Expert

TL;DR: Institutional reporting is transparent; board connection disclosed as deputization but no change in governance control disclosed.

The Form 4 discloses JANA’s indirect ownership and a board connection via Scott Ostfeld, a JANA managing partner who serves on Mercury Systems’ board; the filing explicitly frames that director status is by deputization. The report is procedurally complete: it states the transaction date, quantity, price, post-transaction holdings, and the stated purpose of rebalancing. There is no assertion in the filing of any change to governance control or new agreements with the issuer, and the filing includes the required signature and dated attestation. Governance implications are limited to the reaffirmed board presence and the reduced economic stake following the reported sale.

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)
08/13/2025

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	08/13/2025		S(1)		797,000	D	$65.42	5,964,313	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 transactions were 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 (the "JANA Funds"). 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 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	08/15/2025
	** 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).
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FAQ

What did JANA Partners report on Form 4 for MRCY?

JANA reported disposing of 797,000 shares of Mercury Systems (MRCY) on 08/13/2025 at a reported price of $65.42, with post-transaction indirect ownership of 5,964,313 shares.

Why did JANA Partners sell MRCY shares according to the filing?

The filing states the transactions were effected for the purpose of rebalancing the holdings of funds and accounts managed by JANA.

How does JANA beneficially own the reported MRCY shares?

Indirectly through various accounts under its management and control (the JANA Funds); the form explains the general partner and founder relationships.

Does the Form 4 indicate a change in governance at Mercury Systems?

No change in governance control is disclosed; the filing notes a board connection by deputization because a JANA managing partner, Scott Ostfeld, serves on the issuer’s board.

When was the Form 4 signed and filed by JANA Partners?

The signature block shows the form was signed by Jennifer Fanjiang on 08/15/2025.