X0508 4 2026-03-09 0 0001918102 DEEP FISSION, INC. NONE 0001950877 JANOVER BLAKE C/O DEEP FISSION, INC. 2001 ADDISON ST., SUITE 300 BERKELEY CA 94704 1 0 0 0 0 Restricted Stock Unit 0 2026-03-09 4 A 0 3334 0 A 2027-03-09 2033-03-09 Common Stock 3334 103334 D Each restricted stock unit represents a contingent right to receive one share of the Issuer's common stock upon vesting. The units vest on the one-year anniversary of the grant date, provided the holder continues to provide service through the vesting date. After the units vest, the holder may elect to defer receipt of the shares until the earlier of a qualifying distribution event or the termination of service, as permitted under the Issuer's equity incentive plan. /s/ Jon Gordon, as Attorney-in-Fact for Blake Janover 2026-03-10