[Form 4] MERCURY SYSTEMS INC Insider Trading Activity

Rhea-AI Filing Summary

Mercury Systems executive Stuart Kupinsky reported an insider stock sale mainly tied to taxes. As EVP, CLO & Corporate Secretary, he sold 2,287 shares of Mercury Systems common stock in an open-market transaction at an average price of $83.5554 per share.

According to the footnotes, these shares were sold under a sell-to-cover program to satisfy tax withholding obligations upon vesting of stock awards, indicating the sale was driven by tax requirements rather than a discretionary portfolio decision. After this transaction, Kupinsky held 68,010 shares directly and 1,082 shares indirectly through a 401(k) plan.

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^*

KUPINSKY STUART

(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)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	EVP, CLO & Corp Sec

3. Date of Earliest Transaction (Month/Day/Year)
02/17/2026

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	02/17/2026		S		2,287(1)	D	$83.5554(2)	68,010	D
Common Stock								1,082	I	401K Plan

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 shares sold as part of a sell-to-cover program to satisfy tax withholding obligations upon the vesting of stock awards.

2. Represents the per share price attributed to sales of shares on behalf of all participants under the sell-to-cover program on the transaction date indicated.

	/s/ Douglas Munro, attorney-in-fact	02/19/2026
	** 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 Mercury Systems (MRCY) report for Stuart Kupinsky?

Mercury Systems reported that executive Stuart Kupinsky sold 2,287 shares of common stock at $83.5554 per share. The sale was executed under a sell-to-cover program to meet tax withholding obligations linked to vesting stock awards, rather than a discretionary share sale.

Was the MRCY insider sale by Stuart Kupinsky a discretionary transaction?

The filing indicates Kupinsky’s sale was not purely discretionary. Footnotes explain the 2,287 shares were sold as part of a sell-to-cover program to satisfy tax withholding obligations triggered when his stock awards vested, a common administrative mechanism for equity compensation.

How many Mercury Systems (MRCY) shares does Stuart Kupinsky own after the reported sale?

Following the transaction, Kupinsky directly owned 68,010 shares of Mercury Systems common stock. He also indirectly owned 1,082 additional shares through a 401(k) plan, reflecting his remaining economic interest after the sell-to-cover tax withholding sale.

What price did the Mercury Systems (MRCY) insider transaction attribute to the sold shares?

The reported transaction attributed a per-share price of $83.5554 to the 2,287 shares sold. A footnote notes this price represents the average per-share price for all participants’ sales under the sell-to-cover program on the specified transaction date, not a negotiated individual trade.

What role does Stuart Kupinsky hold at Mercury Systems (MRCY) in this Form 4 filing?

In the Form 4, Stuart Kupinsky is identified as an officer of Mercury Systems with the title EVP, CLO & Corporate Secretary. His position explains why his equity transactions, including the sell-to-cover sale, must be reported publicly under insider reporting rules.

How is the 401(k) ownership of Mercury Systems (MRCY) shares reported for Stuart Kupinsky?

The filing shows 1,082 shares of Mercury Systems common stock held indirectly through a 401(k) plan. These shares are classified as indirect ownership, reflecting that they are held in a retirement account rather than directly in Kupinsky’s personal brokerage account.