MERCURY SYSTEMS INC

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 10-K

THE FISCAL YEAR ENDED June 27, 2025

OR

COMMISSION FILE NUMBER 001-41194

(Exact name of registrant as specified in its charter)

978-256-1300

(Registrant’s telephone number, including area code)

SECURITIES REGISTERED PURSUANT TO SECTION 12(b) OF THE

SECURITIES EXCHANGE ACT OF 1934:

SECURITIES REGISTERED PURSUANT TO SECTION 12(g) OF THE

SECURITIES EXCHANGE ACT OF 1934: NONE

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes ý No¨

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. Yes¨ No ý

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ý No¨

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§ 229.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes ý No¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer”, “smaller reporting company” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

Large accelerated filer ý Accelerated filer¨ Non-accelerated filer¨ Smaller reporting company☐

Emerging growth company☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.¨

Indicate by check mark whether the registrant has filed a report on and attestation to its management's assessment of the effectiveness of its internal control over financial report under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C.762(b)) by the registered public accounting firm that prepared or issued its audit report. Yes ý No☐

If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrant included in the filing reflect the correction of an error to previously issued financial statements.¨

Indicate by check mark whether any of those error corrections are restatements that require a recovery analysis of incentive-based compensation received by any of the registrant's executive officers during the relevant recovery period pursuant to Section 240. 10D-1(b).¨

Indicate by check mark whether the registrant is a shell company (as defined by Rule 12b-2 of the Exchange Act). Yes☐ Noý

The aggregate market value of the Common Stock held by non-affiliates of the registrant was approximately $2.5 billion based upon the closing price of the Common Stock as reported on the Nasdaq Global Select Market on December 27, 2024, the last business day of the registrant’s most recently completed second fiscal quarter.

Shares of Common Stock outstanding as of July 31, 2025:59,915,670 shares.

DOCUMENTS INCORPORATED BY REFERENCE

Portions of the registrant’s definitive Proxy Statement for its 2025 Annual Meeting of Shareholders are incorporated by reference into Part III of this report.

Exhibit Index on Page 81

INDEX