Richard Muller - 09 Mar 2026 Form 4 Insider Report for DEEP FISSION, INC.

Reporting relationship: Chief Technology Officer
Issuer ticker: FISN
Reported as of: 09 Mar 2026
Net transaction value: $0
SEC form: 4
Accepted by SEC: 10 Mar 2026, 17:26:33 UTC
Prior SEC filing: 09 Sep 2025
Source filing: View source filing
Reporting owner signature: /s/ Jon Gordon, as Attorney-in-Fact for Richard Muller

Key filing fact

Richard Muller filed Form 4 for DEEP FISSION, INC. on 10 Mar 2026.

Key facts

This page summarizes Richard Muller's Form 4 filing for DEEP FISSION, INC..
1 reported transaction and 1 derivative row are listed below.
Accepted by SEC: 10 Mar 2026, 17:26.

Change

Previous filing in this sequence was filed on 09 Sep 2025.
Current net transaction value: $0.

Research use

This tells you what this filing adds before you inspect full transaction and derivative tables.
You can trace every row back to the original SEC filing document.

Evidence

Filed on Form 4

Ownership activity is grounded in SEC Form 4 disclosures.

View source filing

Reporting Owners (1)

CIK 0002081872 Primary reporting owner

Muller Richard

Relationship: Chief Technology Officer
Address: C/O DEEP FISSION, INC., 2001 ADDISON ST., SUITE 300, BERKELEY
Signature: /s/ Jon Gordon, as Attorney-in-Fact for Richard Muller
Signature date: 10 Mar 2026

Reported derivative securities

Options, warrants, convertible securities, or similar derivative positions disclosed in the filing.

No ticker transaction Derivative

Employee Stock Option (right to buy)

Award

Transaction value
Shares: +223,000
Change %: +34%
Price: $0.000000^*
Shares after: 872,363
Date: 09 Mar 2026
Ownership: Direct
Underlying class: Common Stock
Underlying amount: 223,000
Exercise price: $15.00
Footnotes: F1

^* marks a reported price that did not pass the local price check.

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 1 footnote

Footnote 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.