Statement of Changes in Beneficial Ownership (Form 4)

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b). Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940

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(Print or Type Responses)

1. Name and Address of Reporting Person * Peres Mark Wayne 2. Issuer Name and Ticker or Trading Symbol DEEP FISSION, INC. [NONE] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) Chief Nuclear Officer (Last) (First) (Middle) C/O DEEP FISSION, INC., 2001 ADDISON STREET, SUITE 300 3. Date of Earliest Transaction (Month/Day/Year) 02/19/2026 (Street) BERKELEY, CA 94704 4. If Amendment, Date Original Filed (Month/Day/Year) 6. Individual or Joint/Group Filing (Check Applicable Line) _X_ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

1.Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 3)

2. Conversion or Exercise Price of Derivative Security

3. Transaction Date (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

4. Transaction Code (Instr. 8)

5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5)

6. Date Exercisable and Expiration Date (Month/Day/Year)

7. Title and Amount of Underlying Securities (Instr. 3 and 4)

8. Price of Derivative Security (Instr. 5)

9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)

10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)

11. Nature of Indirect Beneficial Ownership (Instr. 4)

Code

V

(A)

(D)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

Restricted Stock Unit

$ 0

02/19/2026

A

25,000

(1)

02/19/2033

Common Stock

25,000

$ 0

25,000

D

Employee Stock Option (right to buy)

$15

02/19/2026

A

15,000

02/19/2027(2)

02/19/2036

Common Stock

15,000

$ 0

15,000

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Peres Mark Wayne C/O DEEP FISSION, INC. 2001 ADDISON STREET, SUITE 300 BERKELEY, CA 94704			Chief Nuclear Officer

Signatures

/s/ Jon Gordon as attorney-in-Fact for Mark Peres		02/23/2026
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 4(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	Each RSU vests based on attainment of both a service-based vesting condition and liquidity event vesting condition, in each case, prior to the expiration date. 25% of the service-based vesting condition will be satisfied on the one-year anniversary of the grant date and the remainder in equal monthly installments thereafter, subject to the reporting person's continued service through the vesting dates. The liquidity event condition will be satisfied on the earliest to occur of a change in control, initial public offering or direct listing.
(2)	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.

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