Mercury Systems' Ballhaus plans 22K-share stock sale

MERCURY SYSTEMS INC (MRCY) disclosed a planned sale of company common stock by William L. Ballhaus under Rule 144.

Rhea-AI Filing Summary

MERCURY SYSTEMS INC (MRCY) disclosed a planned sale of company common stock by William L. Ballhaus under Rule 144. The notice covers 22,010 shares of common stock associated with a restricted stock vesting event dated August 19, 2026, categorized as compensation.

Ballhaus has also reported recent sales of MRCY common stock during the prior three months, and the filing states that the sale includes an amount necessary to cover a tax obligation arising from the settlement of a vested equity award distribution. Fidelity Brokerage Services LLC signed the notice as attorney-in-fact for Ballhaus.

Key Figures

Planned shares to be sold: 22,010 shares Recent sale 1 – shares: 3,536 shares Recent sale 1 – value: $388,786.39 +4 more

7 metrics

Planned shares to be sold 22,010 shares Common stock tied to restricted stock vesting dated 08/19/2026

Recent sale 1 – shares 3,536 shares Common stock sale by William Ballhaus on 08/17/2026

Recent sale 1 – value $388,786.39 Aggregate value for 3,536 MRCY shares sold on 08/17/2026

Recent sale 2 – shares 24,144 shares Common stock sale by William Ballhaus on 08/18/2026

Recent sale 2 – value $2,688,620.31 Aggregate value for 24,144 MRCY shares sold on 08/18/2026

Recent sale 3 – shares 26,802 shares Common stock sale by William Ballhaus on 08/19/2026

Recent sale 3 – value $2,688,401.42 Aggregate value for 26,802 MRCY shares sold on 08/19/2026

Key Terms

Rule 144, Restricted Stock Vesting, attorney-in-fact, vested equity award distribution

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 | 08/19/2026 | 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 William L. Ballhaus"

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.

vested equity award distribution financial

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

FAQ

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

What insider stock sale is disclosed for MERCURY SYSTEMS INC (MRCY)?

The filing reports that William L. Ballhaus plans to sell 22,010 shares of MRCY common stock. The sale is tied to a restricted stock vesting event dated August 19, 2026 and is classified as compensation-related.

Who is selling MERCURY SYSTEMS INC (MRCY) shares in this Form 144 notice?

William L. Ballhaus is the person for whose account MRCY shares are to be sold. Fidelity Brokerage Services LLC signed the notice as a duly authorized representative and attorney-in-fact for Ballhaus.

How many MERCURY SYSTEMS INC (MRCY) shares did William Ballhaus sell recently?

The notice lists prior 3‑month sales of 3,536 shares, 24,144 shares, and 26,802 shares of MRCY common stock. These transactions occurred on August 17, 18, and 19, 2026, respectively, for stated dollar amounts.

What is the purpose of the planned MRCY share sale related to William Ballhaus?

The remark states the sale includes an amount needed to cover a tax obligation from a vested equity award settlement. The securities to be sold are linked to restricted stock vesting dated August 19, 2026 and categorized as compensation.

On which market are the MERCURY SYSTEMS INC (MRCY) shares in this filing listed?

The common stock referenced in the notice is listed on NASDAQ. The filing identifies the class as common stock of Mercury Systems Inc and specifies NASDAQ as the trading market for these securities.

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

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Accepted by SEC EDGAR 08/20/2026 - 03:15 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	0001436044
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	Ballhaus William L
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
Relationship to Issuer	Director

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	22010	2149791.54	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			22010	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
William Ballhaus 50 Minuteman Road Andover MA 01810	Common	08/17/2026	3536	388786.39
William Ballhaus 50 Minuteman Road Andover MA 01810	Common	08/18/2026	24144	2688620.31
William Ballhaus 50 Minuteman Road Andover MA 01810	Common	08/19/2026	26802	2688401.42

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/Wade Moss, as a duly authorized representative of Fidelity Brokerage Services LLC, as attorney-in-fact for William L. Ballhaus
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)