Mercury Systems CAO sells 657 shares for taxes

MERCURY SYSTEMS INC (MRCY) reported that officer Douglas Munro, SVP and Chief Accounting Officer, sold a total of 657 shares of common stock in August 2026.

Rhea-AI Filing Summary

MERCURY SYSTEMS INC (MRCY) reported that officer Douglas Munro, SVP and Chief Accounting Officer, sold a total of 657 shares of common stock in August 2026. These sales were executed under a sell-to-cover program to satisfy tax withholding obligations upon the vesting of stock awards, and not as discretionary open‑market sales.

Insider Trade Summary

Net Seller: 657 shares

Net Sell 3 txns

Insider Munro Douglas

Role SVP, CAO

Sold 657 shs ($66K)

Type	Security	Shares	Price	Value
Sale	Common Stock F1, F2	109	$97.6734	$11K
Sale	Common Stock F1, F2	548	$100.306	$55K
holding	Common Stock	--	--	--

Holdings After Transaction: Common Stock — 12,982 shares (Direct); Common Stock — 359 shares (Indirect, 401K Plan)

Footnotes (2)

1. F1. Represents shares sold as part of a sell-to-cover program to satisfy tax withholding obligations upon the vesting of stock awards.
2. F2. 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.

Key Figures

Shares sold on August 19, 2026: 548 shares Sale price on August 19, 2026: $100.3060 per share Shares sold on August 20, 2026: 109 shares +3 more

6 metrics

Shares sold on August 19, 2026 548 shares Common Stock sale by Douglas Munro as part of sell-to-cover program

Sale price on August 19, 2026 $100.3060 per share Attributed per-share price for sell-to-cover sales on behalf of participants

Shares sold on August 20, 2026 109 shares Common Stock sale by Douglas Munro as part of sell-to-cover program

Sale price on August 20, 2026 $97.6734 per share Attributed per-share price for sell-to-cover sales on behalf of participants

Total shares sold 657 shares Aggregate of the two reported Common Stock sales in August 2026

Indirect holdings in 401K Plan 359 shares Common Stock held indirectly through a 401K Plan as of August 19, 2026

Key Terms

sell-to-cover program, tax withholding obligations, vesting of stock awards, 401K Plan

4 terms

sell-to-cover program financial

"Represents shares sold as part of a sell-to-cover program to satisfy tax"

tax withholding obligations financial

"sell-to-cover program to satisfy tax withholding obligations upon the vesting"

vesting of stock awards financial

"tax withholding obligations upon the vesting of stock awards."

401K Plan financial

"total_shares_following_transaction": "359.0000", "direct_or_indirect": "I", "nature_of_ownership": "401K Plan""

A 401(k) plan is an employer-sponsored retirement savings account that lets workers set aside part of their paycheck into investments, often with tax breaks and sometimes with matching contributions from the employer. Think of it as a workplace piggy bank that grows through employee contributions, optional company top-ups, and market returns; it matters to investors because it shapes household retirement security, drives large flows of money into public markets, and affects a company’s compensation costs and ability to attract and keep talent.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What insider transactions did MRCY disclose for Douglas Munro in this Form 4?

Douglas Munro reported selling 657 shares of MERCURY SYSTEMS INC common stock in August 2026 through two transactions that were part of a sell-to-cover program related to tax withholding on vested stock awards.

On what dates did Douglas Munro sell MRCY shares and at what prices?

Douglas Munro sold 548 shares of MRCY on August 19, 2026 at $100.3060 per share and 109 shares on August 20, 2026 at $97.6734 per share, as reported in the Form 4.

Were Douglas Munro’s MRCY stock sales part of a discretionary trading decision?

No. Footnotes state the sales represent shares sold as part of a sell-to-cover program to satisfy tax withholding obligations upon the vesting of stock awards, rather than discretionary open-market selling.

How are the reported per-share prices for MRCY determined in this Form 4?

The filing states that the reported per-share prices, such as $97.6734 and $100.3060, represent the per-share price attributed to sales of shares on behalf of all participants under the sell-to-cover program on the indicated dates.

What indirect holdings of MRCY stock does Douglas Munro report after these transactions?

The Form 4 reports 359 shares of MERCURY SYSTEMS INC common stock held indirectly through a 401K Plan as of August 19, 2026.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 08/21/2026 - 04:53 PM EDT Accepted by SEC EDGAR 08/21/2026 - 04:52 PM EDT Learn about SEC filing dates

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^*

Munro Douglas

(Last) (First) (Middle)

50 MINUTEMAN ROAD

(Street)

ANDOVER MASSACHUSETTS 01810

(City) (State) (Zip)

UNITED STATES

(Country)

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)
	SVP, CAO

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
08/19/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

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	08/19/2026		S		548(1)	D	$100.306(2)	13,091	D
Common Stock	08/20/2026		S		109(1)	D	$97.6734(2)	12,982	D
Common Stock								359	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	08/21/2026
	** 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.
* Form 4: SEC 1474 (03-26)