JANA Partners trims Mercury Systems (MRCY) stake with 400,000-share sale

Rhea-AI Filing Summary

JANA Partners Management, LP reported an open-market sale of 400,000 shares of Mercury Systems common stock at $81 per share on February 9, 2026. The position is held indirectly through funds and accounts it manages.

After this transaction, JANA reported 4,566,675 shares beneficially owned indirectly. JANA describes the sale as rebalancing the holdings of its managed funds and accounts and disclaims beneficial ownership beyond its pecuniary interest. JANA may be deemed a director by deputization because a managing partner serves on Mercury’s board.

Insights

Equity governance and insider-transactions analyst

JANA-managed funds sold 400,000 Mercury Systems shares as a portfolio rebalance.

The filing shows JANA Partners Management, LP indirectly sold 400,000 Mercury Systems common shares at $81 per share on February 9, 2026, leaving 4,566,675 shares beneficially owned through managed accounts. The transaction is coded as an open-market sale.

Footnotes state the sale was executed to rebalance holdings of funds and accounts JANA manages and that JANA and related entities disclaim beneficial ownership beyond any pecuniary interest. JANA may be deemed a director by deputization via a managing partner serving on the issuer’s board. The filing documents an ownership adjustment rather than a stated change in strategic posture.

Insider Trade Summary

Net Seller: 400,000 shares ($32,400,000)

Net Sell 1 txn

Insider JANA Partners Management, LP

Role Director

Sold 400,000 shs ($32.40M)

Type	Security	Shares	Price	Value
Sale	Common Stock, par value $0.01 per share	400,000	$81.00	$32.40M

Holdings After Transaction: Common Stock, par value $0.01 per share — 4,566,675 shares (Indirect, See footnote)

Footnotes (1)

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

Form 4 Insider Transactions: What Each Field Means →

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^*

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)
02/09/2026

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	02/09/2026		S(1)		400,000	D	$81	4,566,675	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 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	02/11/2026
	** 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.

FAQ

What insider transaction did JANA Partners report for MRCY?

JANA Partners Management, LP reported selling 400,000 shares of Mercury Systems common stock at $81 per share on February 9, 2026. The shares are held indirectly through funds and accounts it manages, and the move was described as a portfolio rebalancing transaction.

How many Mercury Systems (MRCY) shares does JANA report owning after the sale?

After the reported sale, JANA reported beneficial ownership of 4,566,675 Mercury Systems common shares on an indirect basis. These shares are held through various accounts under its management and control, with JANA and related entities disclaiming ownership beyond any pecuniary interest they may have.

Was the JANA Partners MRCY trade an open-market sale or another type?

The filing identifies the JANA Partners transaction as an open-market sale coded “S” on February 9, 2026 at $81 per share. This code indicates a sale in the open market or a private transaction, rather than an option exercise or other derivative-related activity.

Why did JANA Partners execute this Mercury Systems share sale?

JANA stated the transaction was effected to rebalance the holdings of funds and accounts it manages. This suggests an internal portfolio allocation decision rather than a stated change in long-term view on Mercury Systems, based solely on the language provided in the disclosure footnote.

What is JANA Partners’ relationship to Mercury Systems (MRCY)?

JANA may be deemed a director by deputization because its managing partner and portfolio manager, Scott Ostfeld, serves on Mercury Systems’ board. JANA is a private money management firm that beneficially owns shares through managed accounts, with beneficial ownership limited to any pecuniary interest.

Does JANA Partners claim full beneficial ownership of its MRCY shares?

No. JANA, its general partner, and founder Barry Rosenstein disclaim beneficial ownership of Mercury Systems securities beyond any pecuniary interest. The shares are reported as held through various accounts under JANA’s management and control, reflecting its role as an investment manager.