Mercury Systems officer plans $646K stock sale

MERCURY SYSTEMS INC (MRCY) disclosed that officer David E. Farnsworth plans to sell up to 6,612 shares of common stock under Rule 144 following restricted stock vesting, using Fidelity Brokerage Services LLC as broker.

Rhea-AI Filing Summary

MERCURY SYSTEMS INC (MRCY) disclosed that officer David E. Farnsworth plans to sell up to 6,612 shares of common stock under Rule 144 following restricted stock vesting, using Fidelity Brokerage Services LLC as broker. In the three days prior, he reported sales of 1,345, 7,347, and 8,155 common shares, with disclosed transaction amounts, and noted that part of the sale proceeds will cover tax obligations from a vested equity award.

Key Figures

Planned shares to be sold: 6,612 shares Reported sale 08/17/2026: 1,345 shares Reported sale amount 08/17/2026: 147,883.96 +5 more

8 metrics

Planned shares to be sold 6,612 shares Common stock listed under Securities To Be Sold

Reported sale 08/17/2026 1,345 shares Common stock sold during the past 3 months

Reported sale amount 08/17/2026 147,883.96 Dollar amount associated with 1,345-share sale

Reported sale 08/18/2026 7,347 shares Common stock sold during the past 3 months

Reported sale amount 08/18/2026 818,145.03 Dollar amount associated with 7,347-share sale

Reported sale 08/19/2026 8,155 shares Common stock sold during the past 3 months

Reported sale amount 08/19/2026 817,995.43 Dollar amount associated with 8,155-share sale

Planned sale valuation row figure 645,816.52 Figure associated with 6,612 planned shares in Securities Information table

Key Terms

Rule 144, restricted stock, vested equity award, attorney-in-fact

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 financial

"Common | 08/19/2026 | Restricted Stock Vesting | Issuer"

Shares granted to an individual that carry limits on transfer or sale until certain conditions are met, such as staying with the company for a set time or hitting performance targets. Think of them as a locked gift that gradually opens; for investors they matter because they affect how many shares may enter the market later, signal management incentives and potential dilution, and reveal confidence in future company performance.

vested equity award financial

"resulting from the settlement of a vested equity award distribution."

attorney-in-fact regulatory

"as attorney-in-fact for David Farnsworth"

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.

FAQ

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

What insider transaction did MRCY report for David E. Farnsworth?

MRCY reported that officer David E. Farnsworth intends to sell up to 6,612 shares of common stock under Rule 144. The proposed sale is linked to the vesting of restricted stock and will be executed through Fidelity Brokerage Services LLC.

How many MRCY shares has David E. Farnsworth sold recently?

Farnsworth reported selling 1,345 shares on August 17, 7,347 shares on August 18, and 8,155 shares on August 19, 2026. Each transaction involved MRCY common stock and is listed in the Rule 144 notice with corresponding dollar amounts.

What is the purpose of David E. Farnsworth’s planned MRCY share sale?

The filing states that the sale includes an amount necessary to cover a tax obligation arising from settlement of a vested equity award. This links the planned Rule 144 sale to compensation-related restricted stock vesting.

Which broker is handling the planned MRCY Rule 144 sale?

The planned sale of MRCY shares will be handled by Fidelity Brokerage Services LLC. The broker is listed alongside the common stock being sold under Rule 144 in the notice filed for David E. Farnsworth.

On which market are the MRCY shares in this Rule 144 notice traded?

The notice identifies the market for the MRCY common stock as NASDAQ. This indicates that the reported and proposed transactions in Mercury Systems Inc. common shares occur on that trading venue.

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

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Accepted by SEC EDGAR 08/20/2026 - 03:29 PM EDT 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	0001990150
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	Farnsworth David E.
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	6612	645816.52	60136133	08/20/2026	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	08/19/2026	Restricted Stock Vesting	Issuer			6612	08/19/2026	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
David E. Farnsworth 50 Minuteman Road Andover MA 01810	Common	08/17/2026	1345	147883.96
David E. Farnsworth 50 Minuteman Road Andover MA 01810	Common	08/18/2026	7347	818145.03
David E. Farnsworth 50 Minuteman Road Andover MA 01810	Common	08/19/2026	8155	817995.43

144: Remarks and Signature

Remarks	Sale includes an amount necessary to cover a tax obligation resulting from the settlement of a vested equity award distribution.
Date of Notice	08/20/2026
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/ Daniel Tucci, as a duly authorized representative of Fidelity Brokerage Services LLC, as attorney-in-fact for David Farnsworth
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)