Mercury insider plans sale of 100,121 shares

MERCURY SYSTEMS INC (MRCY) is the issuer for which William L. Ballhaus filed a notice of proposed sale of common stock under Rule 144.

Rhea-AI Filing Summary

MERCURY SYSTEMS INC (MRCY) is the issuer for which William L. Ballhaus filed a notice of proposed sale of common stock under Rule 144. The notice lists a proposed sale of 100,121 shares of common stock, to be sold through Fidelity Brokerage Services LLC on NASDAQ, with the shares to be acquired via stock option exercise for cash on 08/24/2026.

The filing also reports prior sales of MERCURY SYSTEMS INC common stock by William Ballhaus during the past three months, including transactions on 08/17/2026, 08/18/2026, 08/19/2026, 08/20/2026, and 08/21/2026, with share amounts and aggregate dollar values disclosed for each date.

Key Figures

Proposed shares to be sold under Rule 144: 100,121 shares of common stock Sale date for proposed transaction: 08/24/2026 Shares sold on 08/17/2026: 3,536 shares +4 more

7 metrics

Proposed shares to be sold under Rule 144 100,121 shares of common stock Shares of Mercury Systems Inc to be sold by William L. Ballhaus

Sale date for proposed transaction 08/24/2026 Date associated with proposed Rule 144 sale and stock option exercise

Shares sold on 08/17/2026 3,536 shares Mercury Systems Inc common stock sold by William Ballhaus

Aggregate sale amount on 08/17/2026 $388,786.39 Total dollar amount for 3,536 MRCY shares sold

Shares sold on 08/21/2026 65,000 shares Largest single-day reported sale in the three-month period

Aggregate sale amount on 08/21/2026 $6,006,465.86 Total dollar amount for 65,000 MRCY shares sold

Issuer phone number 978-256-1300 Contact phone for Mercury Systems Inc

Key Terms

Rule 144, Stock Option Exercise, attorney-in-fact, Common, +1 more

5 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.

Stock Option Exercise financial

"Common | 08/24/2026 | Stock Option Exercise | Issuer"

A stock option exercise is the act of using a previously granted right to buy shares of a company's stock at a specific, predetermined price by paying that price and receiving the shares. It matters to investors because exercising changes who owns the shares (which can dilute existing ownership), can trigger taxable events and shift potential gains or losses, and affects voting power and the company’s outstanding share count—like turning a voucher into an actual product that becomes part of circulating supply.

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.

Common financial

"Common | Fidelity Brokerage Services LLC 900 Salem Street Smithfield"

NASDQ market

"60136133 | 08/24/2026 | NASDAQ"

FAQ

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

What does the Form 144 filing for MRCY disclose about planned share sales?

The Form 144 for MRCY discloses that William L. Ballhaus intends to sell 100,121 shares of Mercury Systems Inc common stock. The shares are to be acquired via a stock option exercise for cash dated 08/24/2026 and sold through Fidelity Brokerage Services LLC on NASDAQ.

Who is selling Mercury Systems Inc (MRCY) shares in this Form 144?

The filing states that William L. Ballhaus is the person for whose account Mercury Systems Inc (MRCY) common shares are to be sold. Fidelity Brokerage Services LLC is identified as the broker, acting via an attorney-in-fact for Ballhaus for purposes of this notice.

How many MRCY shares has William Ballhaus sold in the past three months?

The notice lists sales of Mercury Systems Inc (MRCY) common stock by William Ballhaus on five dates: 3,536 shares on 08/17/2026, 24,144 on 08/18/2026, 26,802 on 08/19/2026, 22,010 on 08/20/2026, and 65,000 on 08/21/2026, each with aggregate dollar amounts disclosed.

What aggregate dollar amounts were reported for recent MRCY share sales by William Ballhaus?

Reported aggregate dollar amounts for Mercury Systems Inc (MRCY) sales by William Ballhaus are $388,786.39 on 08/17/2026, $2,688,620.31 on 08/18/2026, $2,688,401.42 on 08/19/2026, $2,149,791.54 on 08/20/2026, and $6,006,465.86 on 08/21/2026.

Through which broker will the proposed MRCY Rule 144 sale be executed?

The filing identifies Fidelity Brokerage Services LLC as the broker for the proposed Rule 144 sale of Mercury Systems Inc (MRCY) common stock, with trading indicated on NASDAQ. The signature block shows an authorized representative of Fidelity signing as attorney-in-fact for William L. Ballhaus.

What is the nature of the securities to be sold in the MRCY Form 144?

The securities are common stock of Mercury Systems Inc (MRCY). The notice indicates the shares are tied to a stock option exercise on 08/24/2026, with the method of payment described as cash for the exercise.

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

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Available on EDGAR 08/24/2026 - 01:45 PM EDT Accepted by SEC EDGAR 08/24/2026 - 01:44 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	100121	8954914.11	60136133	08/24/2026	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	08/24/2026	Stock Option Exercise	Issuer			100121	08/24/2026	Cash

* 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
William Ballhaus 50 Minuteman Road Andover MA 01810	Common	08/20/2026	22010	2149791.54
William Ballhaus 50 Minuteman Road Andover MA 01810	Common	08/21/2026	65000	6006465.86

144: Remarks and Signature

Remarks
Date of Notice	08/24/2026
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)