X0609 4 2026-04-16 0001049521 MERCURY SYSTEMS INC MRCY 0001671237 Nearhos Barry R false 50 MINUTEMAN ROAD ANDOVER MA 01810 1 0 Common Stock 2026-04-16 4 A 0 245 0 A 31324 D Common Stock 3500 I By Spouse Represents deferred stock units (DSUs) issued in lieu of a quarterly cash retainer payment for service as a director. These DSUs were fully vested upon grant, but do not convert into shares of common stock until the date on which the reporting person ceases to be a member of our Board of Directors. /s/ Douglas Munro, attorney-in-fact 2026-04-17