MERCURY SYSTEMS INC

10b5-1 Plans

During the first quarter ended September 26, 2025, none of the Company’s directors or executive officers adopted, modified orterminated a Rule 10b5-1 trading arrangement or non-Rule 10b5-1 trading arrangement as each term is defined in Section 408(a) of Regulation S-K.

Amendment No. 1 to CEO Employment Agreement

On October 31, 2025, the independent directors on the Board of Directors, upon the recommendation of the Human Capital and Compensation Committee, approved Amendment No. 1 to the Employment Agreement for our Chief Executive Officer. The amendment was approved following a periodic review of the Company's executive severance arrangements performed by the Human Capital and Compensation Committee in consultation with its independent compensation consultant. The amendment provides for a best net benefit limitation provision for purposes of Section 280G of the Internal Revenue Code consistent with the terms of Company’s prior and updated forms of Change of Control Severance Agreement for Executive Vice Presidents. Under this provision, any executive payments or benefits to be provided to our CEO upon a qualified termination in connection with a change in control (“CIC”) would be reduced to the extent necessary to avoid imposition of a CIC excise tax if doing so would maximize our CEO’s net after-tax income. The CEO’s employment agreement is otherwise unchanged by the amendment.

The foregoing description of the Amendment No. 1 to the Employment Agreement for the CEO does not purport to be complete and is qualified in its entirety by reference to the full text of the Amendment No. 1, which is filed as Exhibit 10.2 to this Quarterly Report on Form 10-Q and is incorporated by reference into this Item 5.

Form of Change in Control Agreement and Severance Benefits Agreement for Non-CEO Executives

On October 31, 2025, the Human Capital and Compensation Committee of the Board of Directors approved updated forms of our Change in Control Severance Agreement and our Severance Benefits Agreement for the Company’s Executive Vice Presidents. The updated forms were approved following a periodic review of the Company's executive severance arrangements performed by the Human Capital and Compensation Committee in consultation with its independent compensation consultant. For the form of Change in Control Severance Agreement for Executive Vice Presidents, the cash severance provision has been updated to 2.0x annual target cash compensation from the 1.5x in the prior form of such agreement and provides that all the benefits in the agreement are contingent upon a CIC actually occurring within 18 months prior to or three months after the executive’s termination. The updated Change in Control Severance Agreement also narrows the circumstances under which a qualifying termination giving rise to severance benefits may be deemed to have occurred, and eliminates payments to the executive of compensation during the pendency of, and reimbursement of legal fees in connection with, good faith disputes that may arise under the agreement. For the form of Severance Benefits Agreement for Executive Vice Presidents, which apply to terminations outside the context of a CIC, the updated form provides for a prorated in-flight bonus for the year of termination tied to full-year actual performance compared with the prior form which did not provide such a bonus.

The foregoing description of the forms of Change in Control Agreement and Severance Benefits Agreement for Executive Vice Presidents does not purport to be complete and is qualified in its entirety by reference to the full text of such forms which are filed as Exhibits 10.2. and 10.3, respectively, to this Quarterly Report on Form 10-Q and are incorporated by reference into this Item 5.