Mercury Systems officer plans $338K stock sale

Officer Steven V. Ratner files Form 144 to sell up to 4,000 MRCY shares valued at about $338,000.

Rhea-AI Filing Summary

MERCURY SYSTEMS INC (MRCY) is the issuer for which Steven V. Ratner has filed a Notice of Proposed Sale of Securities on Form 144. Ratner plans to sell up to 4,000 shares of Mercury Systems common stock through Fidelity Brokerage Services LLC, with an aggregate market value of $338,030.40 as of September 3, 2026 on NASDAQ.

The filing lists shares expected to come from restricted stock vesting grants of 2,183, 1,117, and 700 shares scheduled to vest on August 18, 2025, August 14, 2026, and August 17, 2026, respectively. It also reports recent sales in the prior three months, including 2,187 shares sold for $219,369.22 on August 19, 2026.

Key Figures

Shares proposed to be sold: 4,000 shares Aggregate market value of proposed sale: $338,030.40 Restricted stock vesting 1: 2,183 shares +5 more

8 metrics

Shares proposed to be sold 4,000 shares Common stock proposed for sale under Form 144

Aggregate market value of proposed sale $338,030.40 Value of 4,000 shares as of September 3, 2026

Restricted stock vesting 1 2,183 shares Restricted stock vesting on August 18, 2025 from Issuer as compensation

Restricted stock vesting 2 1,117 shares Restricted stock vesting on August 14, 2026 from Issuer as compensation

Restricted stock vesting 3 700 shares Restricted stock vesting on August 17, 2026 from Issuer as compensation

Recent sale on August 19, 2026 2,187 shares for $219,369.22 Common stock sold by Steven V. Ratner during past 3 months

Recent sale on August 18, 2026 1,971 shares for $219,486.03 Common stock sold by Steven V. Ratner during past 3 months

Recent sale on August 17, 2026 1,084 shares for $119,186.78 Common stock sold by Steven V. Ratner during past 3 months

Key Terms

Rule 144, Restricted Stock Vesting, attorney-in-fact, Notice of Proposed Sale of Securities

4 terms

Rule 144 regulatory

"See the definition of "person" in paragraph (a) of Rule 144."

Rule 144 is a U.S. securities regulation that sets conditions under which restricted or insider-held shares can be legally resold to the public, such as required holding periods, availability of public information, limits on how much can be sold at once, and certain filing requirements. For investors it matters because it determines when previously locked-up shares can enter the market — like a release valve that can increase supply, affect share price, and signal insider intent.

Restricted Stock Vesting financial

"Common | 08/18/2025 | Restricted Stock Vesting | Issuer"

Restricted stock vesting is the timetable and conditions under which shares granted to employees or insiders become fully owned and can be sold, typically requiring continued work or meeting performance goals. It matters to investors because large blocks of shares can become tradable at once, which can change share supply and price, and because vesting aligns insiders’ incentives with the company’s long‑term performance—think of it like a timed unlock that both rewards and locks in key people.

attorney-in-fact regulatory

"as attorney-in-fact for Steve V. Ratner."

An attorney-in-fact is the person or entity given legal authority through a power of attorney to act on behalf of another for specific tasks, such as signing documents, voting shares, or handling transactions. For investors, this matters because it lets a trusted representative make timely decisions or complete paperwork when the owner cannot, much like handing keys to someone to run errands on your behalf—so checks on scope and limits of that authority are important.

Notice of Proposed Sale of Securities regulatory

"Name of Person for Whose Account the Securities are To Be Sold"

FAQ

What does the Form 144 filed for MRCY by Steven V. Ratner disclose?

It discloses that Steven V. Ratner intends to sell up to 4,000 shares of Mercury Systems (MRCY) common stock under Rule 144 through Fidelity Brokerage Services LLC, with an aggregate market value of $338,030.40 as of September 3, 2026.

How many MRCY shares are proposed to be sold under this Form 144?

The notice states that up to 4,000 shares of Mercury Systems common stock are proposed to be sold. These sales are to be effected through Fidelity Brokerage Services LLC on NASDAQ as indicated in the filing.

What is the estimated market value of the MRCY shares covered by the Form 144?

The filing lists an aggregate market value of $338,030.40 for the 4,000 shares of Mercury Systems common stock proposed to be sold as of September 3, 2026.

What prior sales of MRCY stock by Steven V. Ratner are reported in the Form 144?

The filing reports several recent sales, including 2,187 shares sold on August 19, 2026 for $219,369.22, and 1,971 shares sold on August 18, 2026 for $219,486.03, among other transactions in August 2026.

What future restricted stock vesting events are tied to the MRCY shares in this Form 144?

The notice links the shares to restricted stock vesting of 2,183 shares on August 18, 2025, 1,117 shares on August 14, 2026, and 700 shares on August 17, 2026, each described as from the Issuer as compensation.

Who is executing the proposed MRCY share sales listed in the Form 144?

The proposed sales are for the account of Steven V. Ratner, identified as an Officer of Mercury Systems, and the notice is signed by Jessica Spraker as a duly authorized representative of Fidelity Brokerage Services LLC, acting as attorney-in-fact for Ratner.

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

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Available on EDGAR 09/03/2026 - 03:58 PM Accepted by SEC EDGAR 09/03/2026 - 03:57 PM Learn about SEC filing dates

Form 144 Filer Information	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 144 NOTICE OF PROPOSED SALE OF SECURITIES PURSUANT TO RULE 144 UNDER THE SECURITIES ACT OF 1933
FORM 144

144: Filer Information

Filer CIK	0001995110
Filer CCC	XXXXXXXX
Is this a LIVE or TEST Filing?	LIVE TEST
Submission Contact Information
Name
Phone
E-Mail Address

144: Issuer Information

Name of Issuer	MERCURY SYSTEMS INC
SEC File Number	001-41194
Address of Issuer	50 MINUTEMAN ROAD ANDOVER MASSACHUSETTS 01810
Phone	9782561300
Name of Person for Whose Account the Securities are To Be Sold	Ratner Steven
See the definition of "person" in paragraph (a) of Rule 144. Information is to be given not only as to the person for whose account the securities are to be sold but also as to all other persons included in that definition. In addition, information shall be given as to sales by all persons whose sales are required by paragraph (e) of Rule 144 to be aggregated with sales for the account of the person filing this notice.
Relationship to Issuer	Officer

144: Securities Information

Title of the Class of Securities To Be Sold	Name and Address of the Broker	Number of Shares or Other Units To Be Sold	Aggregate Market Value	Number of Shares or Other Units Outstanding	Approximate Date of Sale	Name the Securities Exchange
Common	Fidelity Brokerage Services LLC 900 Salem Street Smithfield RI 02917	4000	338030.40	60136133	09/03/2026	NASDAQ

Furnish the following information with respect to the acquisition of the securities to be sold and with respect to the payment of all or any part of the purchase price or other consideration therefor:

144: Securities To Be Sold

Title of the Class	Date you Acquired	Nature of Acquisition Transaction	Name of Person from Whom Acquired	Is this a Gift?	Date Donor Acquired	Amount of Securities Acquired	Date of Payment	Nature of Payment *
Common	08/18/2025	Restricted Stock Vesting	Issuer			2183	08/18/2025	Compensation
Common	08/14/2026	Restricted Stock Vesting	Issuer			1117	08/14/2026	Compensation
Common	08/17/2026	Restricted Stock Vesting	Issuer			700	08/17/2026	Compensation

* If the securities were purchased and full payment therefor was not made in cash at the time of purchase, explain in the table or in a note thereto the nature of the consideration given. If the consideration consisted of any note or other obligation, or if payment was made in installments describe the arrangement and state when the note or other obligation was discharged in full or the last installment paid.

Furnish the following information as to all securities of the issuer sold during the past 3 months by the person for whose account the securities are to be sold.

144: Securities Sold During The Past 3 Months

Name and Address of Seller	Title of Securities Sold	Date of Sale	Amount of Securities Sold	Gross Proceeds
Steven V. Ratner 50 Minuteman Road Andover MA 01810	Common	08/17/2026	1084	119186.78
Steven V. Ratner 50 Minuteman Road Andover MA 01810	Common	08/18/2026	1971	219486.03
Steven V. Ratner 50 Minuteman Road Andover MA 01810	Common	08/19/2026	2187	219369.22
Steven V. Ratner 50 Minuteman Road Andover MA 01810	Common	08/20/2026	1026	100212.91

144: Remarks and Signature

Remarks
Date of Notice	09/03/2026
ATTENTION:
The person for whose account the securities to which this notice relates are to be sold hereby represents by signing this notice that he does not know any material adverse information in regard to the current and prospective operations of the Issuer of the securities to be sold which has not been publicly disclosed. If such person has adopted a written trading plan or given trading instructions to satisfy Rule 10b5-1 under the Exchange Act, by signing the form and indicating the date that the plan was adopted or the instruction given, that person makes such representation as of the plan adoption or instruction date.
Signature	/s/ Jessica Spraker, as a duly authorized representative of Fidelity Brokerage Services LLC, as attorney-in-fact for Steve V. Ratner.
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)