Richard Muller - 05 Sep 2025 Form 4 Insider Report for DEEP FISSION, INC.

Role: Chief Technology Officer, Director
Signature: /s/ Richard Muller
Transactions as of: 05 Sep 2025
Transactions value $: $0
Form type: 4
Filing time: 09 Sep 2025, 17:43:39 UTC
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
Muller Richard	Chief Technology Officer, Director	C/O DEEP FISSION, INC., 2831 GARBER STREET, BERKELEY	/s/ Richard Muller	09 Sep 2025	0002081872

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction		Common Stock	Award		+5.2M			5.2M	05 Sep 2025	Direct	F1

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

Explanation of Responses:

Id	Content
F1	Received in connection with the Issuer's merger (the "Merger") with Deep Fission Inc. ("Legacy Deep Fission") in accordance with the terms of the Agreement and Plan of Merger and Reorganization dated as of September 5, 2025, by and among the Issuer (f/k/a Surfside Acquisition Inc.), Deep Fission Acquisition Co. and Legacy Deep Fission (the "Merger Agreement"), in exchange for shares of Legacy Deep Fission common stock. Pursuant to the terms of the Merger Agreement, at the effective time of the Merger, each issued and outstanding share of Legacy Deep Fission common stock was converted into the right to receive 17.32142 shares of the Issuer's common stock, rounded to the nearest whole share.

Content

Received in connection with the Issuer's merger (the "Merger") with Deep Fission Inc. ("Legacy Deep Fission") in accordance with the terms of the Agreement and Plan of Merger and Reorganization dated as of September 5, 2025, by and among the Issuer (f/k/a Surfside Acquisition Inc.), Deep Fission Acquisition Co. and Legacy Deep Fission (the "Merger Agreement"), in exchange for shares of Legacy Deep Fission common stock. Pursuant to the terms of the Merger Agreement, at the effective time of the Merger, each issued and outstanding share of Legacy Deep Fission common stock was converted into the right to receive 17.32142 shares of the Issuer's common stock, rounded to the nearest whole share.