MERCURY SYSTEMS INC

Insider Trading Arrangements

During the fourth quarter ended July 3, 2026, other than the arrangements discussed in Part II - Item 5 Insider Trading Arrangements, 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.

Amendments to Performance Stock Awards Granted During Fiscal 2024

Effective August 14, 2026, the Human Capital and Compensation Committee of the Board of Directors (the “Compensation Committee”) approved amendments to performance stock awards granted during fiscal 2024 (the “2024 PSAs”) to each of our named executive officers other than our Chief Executive Officer, as further described below.

Prior to the effectiveness of the amendments, the 2024 PSAs provided for stock-based payouts of up to 200% of each recipient’s target shares based on the Company’s adjusted EBITDA margin and organic revenue performance for fiscal 2024-2026, subject to a modifier that could adjust award payouts upward or downward by up to 25 percentage points based on the Company’s total shareholder return relative to other Spade® Defense Index companies (“Relative TSR”) for fiscal 2024-2026. The specific details of these performance and payout criteria are set forth below.

For the fiscal 2024-2026 performance period, the Company’s adjusted EBITDA margin and organic revenue were 10.2% and $2,731, respectively, each of which was insufficient to earn any payout under the 2024 PSAs. However, during this same performance period the Company achieved a strong shareholder return of 265%, and a Relative TSR at the 74.4 th percentile of Spade Defense Index companies, resulting in award recipients earning a calculated payout of 24.4% of their target shares.

Following the end of fiscal 2026, the Compensation Committee engaged in a comprehensive review of the Company’s fiscal 2024-2026 performance. As noted in our 2024 proxy statement, the Company’s 2024 financial performance was negatively impacted by transitory challenges – primarily relating to warranty and inventory reserves, changes in contract cost estimates, renegotiation of underperforming contracts and technical and production challenges relating to our common processing architecture – which were not anticipated at the time the performance targets for the 2024 PSAs were established, obscuring solid performance elsewhere in the business. Furthermore, these challenges emerged at a time that our leadership team was newly reconstituted, including our Chief Executive Officer, Chief Financial Officer and Chief Legal Officer, each of whom was appointed to their respective roles during or immediately prior to the start of fiscal 2024. Nonetheless, the Company responded to these challenges with considerable progress in our priority areas during 2024, accompanied by substantially improved financial results in the second half of fiscal 2024 and continuing with strong performance through fiscal 2025 and 2026.

The Committee further instructed its independent compensation consultant to prepare a review of the alignment of pay with performance for each of our named executive officers during the fiscal 2024-2026 time period, including alternatives for addressing dislocations in a manner that maintains our desired pay-for-performance philosophy consistent with the continuing leadership team’s financial and shareholder return achievements. Following a review of this analysis and of the Company’s performance as described above, the Committee determined to amend the 2024 PSAs awarded to our Chief Financial Officer, Chief Legal Officer and Chief Human Resources Officer to provide for an additional payout of 50% of their respective target shares (representing the Threshold payout under the 2024 PSAs based on financial performance measures), contingent on their continued employment for an additional one-year vesting period, with each of the recipients consenting to the amendment of their respective 2024 PSA award agreement. The Committee further determined that it would not amend the 2024 PSAs awarded to our Chief Executive Officer, who agreed with the Committee’s determination. No other Company employees held 2024 PSAs at the time of the Committee’s determinations. The specific details of the amended payouts under the 2024 PSAs are set forth below.

(1) Reflects two separate awards made to Mr. Farnsworth on the same date, under which he was granted 41,017 target shares in connection with his hire and 22,559 target shares as part of his annual compensation for fiscal year 2024.

The foregoing description of the amendments to the 2024 PSAs does not purport to be complete and is qualified in its entirety by reference to the full text of the form of amendment filed as Exhibit 10.16 to this Annual Report on Form 10-K and is incorporated by reference into this Item 9B.