Elizabeth Muller - 09 Dec 2025 Form 4 Insider Report for DEEP FISSION, INC.

Reporting relationship: Chief Executive Officer
Issuer ticker: FISN on Nasdaq
Reported as of: 09 Dec 2025
Net transaction value: $0
SEC form: 4
Accepted by SEC: 12 Dec 2025, 17:02:39 UTC
Prior SEC filing: 21 Nov 2025
Next SEC filing: 10 Mar 2026
Source filing: View source filing
Reporting owner signature: /s/ Jon Gordon, as Attorney-in-Fact for Elizabeth Muller

Key filing fact

Elizabeth Muller filed Form 4 for DEEP FISSION, INC. on 12 Dec 2025.

Key facts

This page summarizes Elizabeth Muller's Form 4 filing for DEEP FISSION, INC..
2 reported transactions and 1 derivative row are listed below.
Accepted by SEC: 12 Dec 2025, 17:02.

Change

Previous filing in this sequence was filed on 21 Nov 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 0002081850 Primary reporting owner

Muller Elizabeth

Relationship: Chief Executive Officer
Address: 2831 GARBER STREET, BERKELEY
Signature: /s/ Jon Gordon, as Attorney-in-Fact for Elizabeth Muller
Signature date: 12 Dec 2025

Reported non-derivative transactions

Shares, units, or other non-derivative securities reported in this filing.

No ticker transaction

Restricted Stock Units

Award

Transaction value: $0
Shares: +549,451
Change %
Price: $0.000000
Shares after: 549,451
Date: 09 Dec 2025
Ownership: Direct
Footnotes: F1

Reported derivative securities

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

No ticker transaction Derivative

Stock Option (right to buy)

Award

Transaction value: $0
Shares: +183,150
Change %: +23%
Price: $0.000000
Shares after: 994,849
Date: 09 Dec 2025
Ownership: Direct
Underlying class: shares of Common Stock
Underlying amount: 183,150
Exercise price: $2.73
Footnotes: F2

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

Additional SEC filing notes

Filing notes and footnotes

Explanation of responses 2 footnotes

Footnote F1

Each restricted stock unit represents the contingent right to receive one share of the Issuer's common stock upon vesting. The units vest over four years, with 25% of the award vesting on the first anniversary of the December 9, 2025 grant date and the remaining 75% vesting in equal monthly installments thereafter, subject to the Reporting Person's continued service through each vesting date. Restricted stock units do not have an expiration date.

Footnote F2

The stock options vest over four years, with 25% of the award vesting on the first anniversary of the December 9, 2025 grant date and the remaining 75% vesting in equal monthly installments thereafter, subject to the Reporting Person's continued service through each vesting date.

SEC remarks

Chief Executive Officer (Section 16 Officer). The equity awards reported herein were approved by the Issuer's Compensation Committee pursuant to Rule 16b-3. Power of Attorney authorizing the signer to execute and file this Form 4 on behalf of the Reporting Person is filed as Exhibit 24.