Mercury Systems insider plans $730K stock sale

MERCURY SYSTEMS INC (MRCY) is the issuer for a notice under Rule 144 filed for the account of William L. Ballhaus.

Rhea-AI Filing Summary

MERCURY SYSTEMS INC (MRCY) is the issuer for a notice under Rule 144 filed for the account of William L. Ballhaus. The notice covers a proposed sale of 8,088 shares of common stock, with an aggregate market value of $729,964.73, when 60,136,133 shares of common stock were outstanding on 08/24/2026. The shares to be sold were acquired on 08/24/2026 through a stock option exercise paid in cash. In the prior three months, Ballhaus reported multiple sales of MRCY common stock totaling several tranches between 3,536 and 65,000 shares on dates from 08/17/2026 to 08/21/2026.

Key Figures

Shares proposed to be sold: 8,088 shares Aggregate market value of proposed sale: $729,964.73 Shares outstanding: 60,136,133 shares +5 more

8 metrics

Shares proposed to be sold 8,088 shares Common stock covered by the Rule 144 notice

Aggregate market value of proposed sale $729,964.73 Value of 8,088 shares of common stock

Shares outstanding 60,136,133 shares MRCY common stock outstanding as of 08/24/2026

Sale on 08/17/2026 3,536 shares; $388,786.39 Common stock sold by William L. Ballhaus

Sale on 08/18/2026 24,144 shares; $2,688,620.31 Common stock sold by William L. Ballhaus

Sale on 08/19/2026 26,802 shares; $2,688,401.42 Common stock sold by William L. Ballhaus

Sale on 08/20/2026 22,010 shares; $2,149,791.54 Common stock sold by William L. Ballhaus

Sale on 08/21/2026 65,000 shares; $6,006,465.86 Common stock sold by William L. Ballhaus

Key Terms

Rule 144, Stock Option Exercise, attorney-in-fact, aggregate market value

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.

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.

aggregate market value financial

"8088 | 729964.73 | 60136133 | 08/24/2026"

Aggregate market value is the combined price you would pay to buy all outstanding shares of a company or all companies in a group at current market prices — essentially the sum of each stock’s market capitalization. It matters to investors because it shows the overall size and weight of an investment or sector (like the total cost to buy every piece of a puzzle), helps compare scale across companies or markets, and influences index composition and risk exposure.

FAQ

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

What does the Form 144 filing mean for MERCURY SYSTEMS INC (MRCY)?

The filing gives notice that 8,088 shares of MRCY common stock held for the account of William L. Ballhaus may be sold under Rule 144. It does not itself execute a sale but discloses an intent to sell restricted or control securities.

How many MRCY shares are covered by this Form 144 notice?

The notice covers a proposed sale of 8,088 shares of MERCURY SYSTEMS INC common stock. These shares have an aggregate market value of $729,964.73 as stated in the filing.

How many MRCY shares were outstanding when this Form 144 was filed?

The filing reports that 60,136,133 shares of MERCURY SYSTEMS INC common stock were outstanding as of 08/24/2026. This figure is a baseline for the company’s total common shares, not the amount being sold.

What recent MRCY stock sales has William L. Ballhaus reported?

Over the prior three months, the filing lists MRCY common stock sales by William L. Ballhaus including 3,536 shares on 08/17/2026, 24,144 shares on 08/18/2026, 26,802 shares on 08/19/2026, 22,010 shares on 08/20/2026, and 65,000 shares on 08/21/2026.

How were the MRCY shares in this Form 144 acquired?

The 8,088 shares of MRCY common stock covered by the notice were acquired through a stock option exercise on 08/24/2026, with the filing indicating the consideration was paid in cash.

Who is acting for William L. Ballhaus in this MRCY Form 144 filing?

The signature block shows the notice signed by /s/ Adam Gehring as a duly authorized representative of Fidelity Brokerage Services LLC, acting as attorney-in-fact for William L. Ballhaus.

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

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Available on EDGAR 08/24/2026 - 04:40 PM EDT Accepted by SEC EDGAR 08/24/2026 - 04:40 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	8088	729964.73	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			8088	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 L. Ballhaus 50 Minuteman Road Andover MA 01810	Common	08/17/2026	3536	388786.39
William L. Ballhaus 50 Minuteman Road Andover MA 01810	Common	08/18/2026	24144	2688620.31
William L. Ballhaus 50 Minuteman Road Andover MA 01810	Common	08/19/2026	26802	2688401.42
William L. Ballhaus 50 Minuteman Road Andover MA 01810	Common	08/20/2026	22010	2149791.54
William L. 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/ Adam Gehring, 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)