BlackRock, Inc. (MRCY holder) discloses 8.6M-share, 14.4% Mercury Systems position

Rhea-AI Filing Summary

BlackRock, Inc. reports beneficial ownership of common stock of Mercury Systems Inc. As of the reporting date, BlackRock’s reporting business units beneficially owned 8,619,527 shares of Mercury Systems common stock, representing 14.4% of the outstanding class.

BlackRock reports sole voting power over 8,513,183 shares and sole dispositive power over 8,619,527 shares, with no shared voting or dispositive power. The filing notes that the interest of iShares Core S&P Small-Cap ETF in Mercury Systems’ common stock exceeds five percent of the total outstanding common stock.

Key Figures

Beneficially owned shares: 8,619,527 shares Ownership percentage: 14.4% Sole voting power: 8,513,183 shares +3 more

6 metrics

Beneficially owned shares 8,619,527 shares Common stock of Mercury Systems beneficially owned by BlackRock reporting business units

Ownership percentage 14.4% Percent of Mercury Systems common stock class beneficially owned

Sole voting power 8,513,183 shares Shares of Mercury Systems over which BlackRock has sole voting power

Shared voting power 0 shares Shares of Mercury Systems over which BlackRock has shared voting power

Sole dispositive power 8,619,527 shares Shares of Mercury Systems over which BlackRock has sole dispositive power

Shared dispositive power 0 shares Shares of Mercury Systems over which BlackRock has shared dispositive power

Key Terms

beneficially owned, Sole Voting Power, Sole Dispositive Power, Schedule 13G, +1 more

5 terms

beneficially owned financial

"this reflects the securities beneficially owned, or deemed to be beneficially owned, by"

Beneficially owned describes securities or assets where a person has the economic rights and control—such as the right to receive dividends and to direct voting—even if legal title is held in another name. Think of it like having the keys and using a car that’s registered to someone else: you get the benefits and make decisions. Investors care because beneficial ownership reveals who truly controls value and voting power, affecting corporate decisions and takeover dynamics.

Sole Voting Power financial

"5 | Sole Voting Power 8,513,183.00 6 | Shared Voting Power 0.00"

Sole voting power is the exclusive right to cast votes attached to a shareholder’s stock without needing approval from anyone else. Like holding the only remote control for a TV, it lets that holder decide corporate matters such as board members, mergers, and policy changes, making it important to investors because it concentrates control and can strongly influence a company’s strategy and the value of its shares.

Sole Dispositive Power financial

"7 | Sole Dispositive Power 8,619,527.00 8 | Shared Dispositive Power 0.00"

Sole dispositive power is the exclusive legal authority to decide what happens to a security — for example, whether to sell, transfer, or retain shares — without needing anyone else’s permission. Investors care because it signals who truly controls the economic outcome of an investment: like holding the only key to a safe, the holder can realize gains or losses and may trigger regulatory reporting, insider rules, or influence over corporate ownership.

Schedule 13G regulatory

"If a parent holding company has filed this schedule, pursuant to (ii)(G), so indicate under"

A Schedule 13G is a formal document that investors file with the government when they acquire a large ownership stake in a company, usually for investment purposes rather than control. It helps keep the public informed about who owns significant parts of a company's shares, which can influence how the company is managed and how investors make decisions. Filing this schedule is important for transparency and understanding the ownership landscape of publicly traded companies.

Power of Attorney legal

"Exhibit Information Exhibit 24: Power of Attorney Exhibit 99: Item 7"

A power of attorney is a legal document that allows one person to make decisions and act on behalf of another person, often in financial or legal matters. It’s like giving someone a trusted helper or agent the authority to handle important tasks if you are unable to do so yourself. This matters to investors because it can impact how their assets are managed or transferred if they become unable to oversee their affairs.

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

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Available on EDGAR 07/29/2026 - 03:22 PM Accepted by SEC EDGAR 07/29/2026 - 03:19 PM Learn about SEC filing dates

FAQ

How many Mercury Systems (MRCY) shares does BlackRock beneficially own?

BlackRock’s reporting business units beneficially own 8,619,527 shares of Mercury Systems common stock. This stake represents a 14.4% ownership of the outstanding common stock as disclosed in the Schedule 13G/A filing.

What percentage of Mercury Systems (MRCY) is owned by BlackRock?

BlackRock reports beneficial ownership of 14.4% of Mercury Systems’ common stock. This percentage is based on 8,619,527 shares beneficially owned by certain BlackRock business units, as stated in the Schedule 13G/A amendment.

How much voting power does BlackRock have in Mercury Systems (MRCY)?

BlackRock reports sole voting power over 8,513,183 shares of Mercury Systems common stock. It reports no shared voting power, indicating all reported voting authority is held on a sole basis by the reporting business units.

What dispositive power over Mercury Systems (MRCY) shares does BlackRock report?

BlackRock reports sole dispositive power over 8,619,527 shares of Mercury Systems common stock. The filing states there is no shared dispositive power, so all reported disposition authority is held solely by the reporting business units.

Which BlackRock-affiliated fund holds more than 5% of Mercury Systems (MRCY)?

The filing notes that iShares Core S&P Small-Cap ETF has an interest in Mercury Systems common stock that is more than five percent of the company’s total outstanding common stock, within BlackRock’s reported holdings framework.

Who signed the Schedule 13G/A filing for Mercury Systems (MRCY) on behalf of BlackRock?

The Schedule 13G/A was signed by Spencer Fleming, identified as a Managing Director at BlackRock, Inc. The signature is supported by a Power of Attorney attached as Exhibit 24 to the filing.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 19)

MERCURY SYSTEMS INC

(Name of Issuer)

Common Stock

(Title of Class of Securities)

589378108

(CUSIP Number)

06/30/2026

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

schemaVersion:

SCHEDULE 13G

CUSIP Number(s): 589378108

1

Names of Reporting Persons

BlackRock, Inc.

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 8,513,183.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 8,619,527.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

8,619,527.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

14.4 %

12

Type of Reporting Person (See Instructions)

HC

SCHEDULE 13G

Item 1.
(a)	Name of issuer: MERCURY SYSTEMS INC
(b)	Address of issuer's principal executive offices: 50 MINUTEMAN ROAD ANDOVER MA 01810
Item 2.
(a)	Name of person filing: BlackRock, Inc. In accordance with SEC Release No. 34-39538 (January 12, 1998), this Schedule 13G reflects the securities beneficially owned, or deemed to be beneficially owned, by certain business units (collectively, the "Reporting Business Units") of BlackRock, Inc. and its subsidiaries and affiliates. It does not include securities, if any, beneficially owned by other business units whose beneficial ownership of securities are disaggregated from that of the Reporting Business Units in accordance with such release.
(b)	Address or principal business office or, if none, residence: BlackRock, Inc., 50 Hudson Yards New York, NY 10001
(c)	Citizenship: See Item 4 of Cover Page
(d)	Title of class of securities: Common Stock
(e)	CUSIP No.: 589378108
Item 4.	Ownership
(a)	Amount beneficially owned: 8619527
(b)	Percent of class: 14.4 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 8513183
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 8619527
	(iv) Shared power to dispose or to direct the disposition of: 0
Item 5.	Ownership of 5 Percent or Less of a Class.
	Not Applicable
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	If any other person is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, such securities, a statement to that effect should be included in response to this item and, if such interest relates to more than 5 percent of the class, such person should be identified. A listing of the shareholders of an investment company registered under the Investment Company Act of 1940 or the beneficiaries of employee benefit plan, pension fund or endowment fund is not required. The interest of 1 such person, iShares Core S&P Small-Cap ETF, in the common stock of MERCURY SYSTEMS INC is more than five percent of the total outstanding common stock.
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	If a parent holding company has filed this schedule, pursuant to Rule 13d-1(b)(ii)(G), so indicate under Item 3(g) and attach an exhibit stating the identity and the Item 3 classification of the relevant subsidiary. If a parent holding company has filed this schedule pursuant to Rule 13d-1(c) or Rule 13d-1(d), attach an exhibit stating the identification of the relevant subsidiary. See Exhibit 99
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under § 240.14a-11.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

BlackRock, Inc.

Signature:	Spencer Fleming
Name/Title:	Managing Director
Date:	07/29/2026

Exhibit Information

Exhibit 24: Power of Attorney Exhibit 99: Item 7