William Mark Schmitz - 18 Feb 2026 Form 4 Insider Report for DEEP FISSION, INC.

Role: Chief Financial Officer
Signature: /s/ Jon Gordon as attorney-in-Fact for William Mark Schmitz
Issuer symbol: N/A
Transactions as of: 18 Feb 2026
Net transactions value: $0
Form type: 4
Filing time: 23 Feb 2026, 21:18:13 UTC
Previous filing: 09 Sep 2025
Next filing: 10 Mar 2026
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Schmitz William Mark	Chief Financial Officer	C/O DEEP FISSION, INC., 2001 ADDISON STREET, SUTIE 300, BERKELEY	/s/ Jon Gordon as attorney-in-Fact for William Mark Schmitz	23 Feb 2026	0001409378

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction		Employee Stock Option (right to buy)	Award	$0	+15,000		$0.000000	15,000	18 Feb 2026	Common Stock	15,000	$15.00	Direct	F1

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	Date at which first vesting occurs is indicated. One-fourth of the total number of options to purchase the Company's common stock vests on the first vesting date shown and an additional one-thirty sixth on each month thereafter until fully vested.