Form: EFFECT

Notice of Effectiveness

May 4, 2026

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

Notice of Effectiveness

Effectiveness Date: May 1, 2026
Accession Number: 0001104659-26-045965
Submission Type: POS AM
CIK: 0001918102
Company Name: DEEP FISSION, INC.
File Number: 333-290438