Mercury Systems insider may sell 24K shares

MERCURY SYSTEMS INC (MRCY) received a Rule 144 notice indicating that William L. Ballhaus may sell up to 24,144 common shares through Fidelity Brokerage Services LLC on or after August 18, 2026.

Rhea-AI Filing Summary

MERCURY SYSTEMS INC (MRCY) received a Rule 144 notice indicating that William L. Ballhaus may sell up to 24,144 common shares through Fidelity Brokerage Services LLC on or after August 18, 2026. These shares were acquired on August 17, 2026 via restricted stock vesting as compensation, and part of the sale is intended to cover related tax obligations.

As context, 60,043,283 common shares were outstanding, and in the prior three months Ballhaus sold 3,536 shares for an aggregate of $388,786.39.

Key Figures

Shares to be sold under Rule 144: 24,144 shares Shares outstanding: 60,043,283 shares Recent shares sold: 3,536 shares +2 more

5 metrics

Shares to be sold under Rule 144 24,144 shares Maximum MRCY common shares listed for potential sale by William L. Ballhaus

Shares outstanding 60,043,283 shares MRCY common shares outstanding as referenced in the notice

Recent shares sold 3,536 shares MRCY common shares sold by William L. Ballhaus on 08/17/2026

Aggregate proceeds from recent sale $388,786.39 Total proceeds from the 3,536 MRCY shares sold on 08/17/2026

Planned sale date 08/18/2026 Date listed for potential sale of 24,144 MRCY shares on NASDAQ

Key Terms

Rule 144, restricted stock vesting, vested equity award distribution

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.

restricted stock vesting financial

"Common | 08/17/2026 | 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.

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 does the latest Rule 144 notice disclose for MRCY?

The notice discloses that William L. Ballhaus may sell up to 24,144 MRCY common shares under Rule 144. These shares come from recently vested restricted stock and include an amount intended to cover related tax obligations.

How many Mercury Systems (MRCY) shares is William L. Ballhaus planning to sell?

William L. Ballhaus may sell up to 24,144 MRCY common shares under Rule 144 through Fidelity Brokerage Services LLC. The shares were acquired via restricted stock vesting on August 17, 2026 as part of compensation.

What is the source of the MRCY shares being sold by William L. Ballhaus?

The 24,144 MRCY shares subject to potential sale were acquired on August 17, 2026 through restricted stock vesting. The filing states this was a compensation-related equity award, with some shares sold to satisfy tax obligations.

How many Mercury Systems (MRCY) shares has William L. Ballhaus sold recently?

In the past three months, William L. Ballhaus sold 3,536 MRCY common shares on August 17, 2026 for aggregate proceeds of $388,786.39. This transaction is separate from the additional 24,144 shares now noticed for potential sale.

What is the total number of Mercury Systems (MRCY) shares outstanding mentioned in the notice?

The notice lists 60,043,283 MRCY common shares outstanding as a contextual figure. This represents the company’s total common shares at the referenced time, separate from the 24,144 shares that may be sold under Rule 144.

Why does the MRCY Rule 144 notice mention tax obligations?

The notice explains that the sale includes an amount necessary to cover a tax obligation from a vested equity award distribution. This indicates some shares from the 24,144 total may be sold specifically to satisfy associated tax liabilities.

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

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Accepted by SEC EDGAR 08/18/2026 - 03:47 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	24144	2688620.31	60043283	08/18/2026	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	08/17/2026	Restricted Stock Vesting	Issuer			24144	08/17/2026	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 L. Ballhaus 50 Minuteman Road Andover MA 01810	Common	08/17/2026	3536	388786.39

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	08/18/2026
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)