Mercury Systems Inc

Item 1.01 Entry into a Material Definitive Agreement. On September 15, 2026, the independent directors on the Board of Directors of Mercury Systems, Inc. (the “Company”), upon the recommendation of the Human Capital and Compensation Committee, approved Amendment No. 2 to the Employment Agreement for William L. Ballhaus, the Company’s Chairman and Chief Executive Officer. The amendment extends the initial term of the agreement to August 15, 2030. The Employment Agreement is otherwise unchanged by the amendment. The foregoing description of the Amendment No. 2 to the Employment Agreement does not purport to be complete and is qualified in its entirety by reference to the full text of the Amendment No. 2, which is filed as Exhibit 10.1 to this Current Report on Form 8-K and is incorporated by reference into this Item 1.01.

Item 7.01 Regulation FD Disclosure. On September 16, 2026, the Company issued a press release that announced the extension of Mr. Ballhaus’s employment agreement to August 15, 2030, and reaffirmed the financial guidance issued on the Company’s earnings call on August 18, 2026. A copy of the press release is attached hereto as Exhibit 99.1 and is incorporated into this Item 7.01 by reference. The information contained in this Item 7.01, including Exhibit 99.1 attached hereto, is being furnished and shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, except as shall be expressly set forth by specific reference in such a filing.