Mercury Systems (NASDAQ: MRCY) seller plans sale after August trades

Rhea-AI Filing Summary

MERCURY SYSTEMS INC (MRCY) is the issuer for a planned sale of restricted or control common stock under Rule 144 by William L. Ballhaus through Fidelity Brokerage Services LLC. The notice covers 111,076 common shares, with an aggregate market value of $9,676,608.39 and issuer shares outstanding of 60,136,133 as of 08/25/2026.

The shares are tied to a stock option exercise for which the issuer is listed as the counterparty and cash as the form of payment, with a proposed sale date of 08/25/2026 on NASDAQ. Ballhaus has already sold multiple blocks of MRCY common stock in the prior three months, each disclosed with dates, share counts and dollar amounts.

Key Figures

Shares to be sold: 111,076 shares of common stock Aggregate market value of shares to be sold: $9,676,608.39 Shares outstanding: 60,136,133 shares +3 more

6 metrics

Shares to be sold 111,076 shares of common stock Proposed Rule 144 sale related to stock option exercise as of 08/25/2026

Aggregate market value of shares to be sold $9,676,608.39 Value of 111,076 MRCY common shares covered by the Rule 144 notice

Shares outstanding 60,136,133 shares MERCURY SYSTEMS INC common shares outstanding as of 08/25/2026

Sale on 08/17/2026 3,536 shares for $388,786.39 MRCY common shares sold by William L. Ballhaus during past 3 months

Sale on 08/21/2026 65,000 shares for $6,006,465.86 MRCY common shares sold by William L. Ballhaus during past 3 months

Sale on 08/24/2026 108,209 shares for $9,684,881.49 Largest single disclosed sale in the past 3 months in this notice

Key Terms

Rule 144, stock option exercise, attorney-in-fact

3 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 | 08/25/2026 | 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.

FAQ

What amount of MRCY stock is covered by William L. Ballhaus’s Rule 144 notice?

The Rule 144 notice for MERCURY SYSTEMS INC (MRCY) covers a proposed sale of 111,076 common shares. The filing lists an aggregate market value of $9,676,608.39 for these shares, with trading referenced on NASDAQ as of 08/25/2026.

What is the stated aggregate market value of the MRCY shares in this Form 144?

The filing states an aggregate market value of $9,676,608.39 for the 111,076 MRCY common shares covered by the notice. These figures relate to the securities proposed to be sold under Rule 144 as of 08/25/2026.

How many MERCURY SYSTEMS INC (MRCY) shares were outstanding as of the date referenced?

The notice reports that MERCURY SYSTEMS INC had 60,136,133 common shares outstanding as of 08/25/2026. This figure provides context for the size of the proposed Rule 144 sale relative to total shares outstanding.

What recent MRCY stock sales by William L. Ballhaus are disclosed in the last 3 months?

The filing lists several recent MRCY sales by William L. Ballhaus, including 3,536 shares for $388,786.39 on 08/17/2026 and 108,209 shares for $9,684,881.49 on 08/24/2026, along with other dated transactions, each with specific share and dollar amounts.

What is the relationship between the MRCY shares to be sold and stock options?

For MERCURY SYSTEMS INC (MRCY), the securities to be sold section describes the 111,076 common shares as related to a Stock Option Exercise, with the issuer listed and Cash as the consideration, all dated 08/25/2026.

Who is executing the sale for William L. Ballhaus in this MRCY Form 144?

The broker listed is Fidelity Brokerage Services LLC, and the notice is signed /s/ Joshua Schmitt as a duly authorized representative of Fidelity, acting as attorney-in-fact for William L. Ballhaus in connection with this Rule 144 transaction.

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

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Available on EDGAR 08/25/2026 - 03:41 PM Accepted by SEC EDGAR 08/25/2026 - 03:40 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	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	111076	9676608.39	60136133	08/25/2026	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	08/25/2026	Stock Option Exercise	Issuer			111076	08/25/2026	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
William L. Ballhaus 50 Minuteman Road Andover MA 01810	Common	08/24/2026	108209	9684881.49

144: Remarks and Signature

Remarks
Date of Notice	08/25/2026
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/ Joshua Schmitt, 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)