Mercury Systems (MRCY) EVP Ratner gains 437-share deferred comp award

Rhea-AI Filing Summary

Ratner Steven reported acquisition or exercise transactions in this Form 4 filing.

Mercury Systems EVP and CHRO Steven Ratner received 437 shares of common stock on March 16, 2026 as a grant of restricted stock units earned as matching awards under Mercury's Deferred Compensation Matching Plan. Following this award, he holds 34,238 shares directly and 235 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^*

Ratner Steven

(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)
	EVP, CHRO

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
03/16/2026

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	03/16/2026		A		437(1)	A	$0	34,238	D
Common Stock								235	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 the deemed acquisition of restricted stock units earned as matching awards under Mercury's Deferred Compensation Matching Plan following the satisfaction of relevant performance criteria. The award governing these units was granted on December 23, 2024. The number of units earned thereunder was determined on March 16, 2026, and the units became fully vested at that time.

	/s/ Douglas Munro, attorney-in-fact	03/18/2026
	** 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.
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* Form 4: SEC 1474 (03-26)

FAQ

What did Mercury Systems (MRCY) executive Steven Ratner report in this Form 4?

Steven Ratner reported receiving 437 shares of Mercury Systems common stock as a restricted stock unit matching award. The units were earned under the company’s Deferred Compensation Matching Plan and became fully vested once performance criteria were satisfied on March 16, 2026.

How many Mercury Systems (MRCY) shares does Steven Ratner hold after this transaction?

After the transaction, Steven Ratner holds 34,238 Mercury Systems common shares directly and 235 shares indirectly through a 401(k) plan. These figures reflect his updated ownership position following the vesting of 437 restricted stock units earned under a deferred compensation matching award.

What is the nature of the 437-share award to Steven Ratner at Mercury Systems (MRCY)?

The 437 shares represent restricted stock units earned as matching awards under Mercury’s Deferred Compensation Matching Plan. The underlying award was originally granted on December 23, 2024, with the number of units determined and fully vested on March 16, 2026, after performance criteria were met.

Did Steven Ratner buy or sell Mercury Systems (MRCY) shares in the open market?

The filing shows no open-market purchase or sale by Steven Ratner. Instead, he acquired 437 shares at no cost as a compensation-related restricted stock unit matching award, which vested after performance criteria were satisfied under Mercury Systems’ Deferred Compensation Matching Plan.

What does the footnote in Steven Ratner’s Mercury Systems (MRCY) Form 4 explain?

The footnote explains that the reported shares are restricted stock units earned as matching awards under the Deferred Compensation Matching Plan. It clarifies the award was granted on December 23, 2024, with units determined and fully vested on March 16, 2026, after performance criteria were met.

Is Steven Ratner’s Form 4 transaction at Mercury Systems (MRCY) a routine compensation event?

Yes. The Form 4 describes a compensation-related grant of 437 restricted stock units as a matching award under a deferred compensation plan. Such awards, vesting after meeting performance criteria, are typically part of ongoing executive compensation rather than discretionary open-market trading activity.