{"transactions":[{"id":851591,"issuer":{"id":5748,"kind":"organization","name":"DEEP FISSION, INC."},"owners":[{"id":61804,"kind":"person","name":"Muller Richard","position":1,"cik":"0002081872","reported_name":"Muller Richard","relationship":{"director":false,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Technology Officer"}}],"security":"Employee Stock Option (right to buy)","published_at":"2026-03-10T17:26:33.000Z","date":"2026-03-09","kind":"grant","planned":false,"acquired":true,"shares":223000,"price":0,"value":0.0,"ownership":{"direct":true},"footnotes":[{"field":"derivative.exercise_date","element":"exerciseDate","label":"F1","text":"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."}],"balance_after":872363,"derivative":{"exercise_price":15,"exercise_date":"2027-03-09","expiration_date":"2036-03-09","underlying":"Common Stock","underlying_shares":223000},"source":{"system":"sec-edgar","filing":"0001104659-26-025947","document":"tm268353-4_4seq1.xml","document_sequence":1,"table":"derivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2081872/000110465926025947/tm268353-4_4seq1.xml","form_type":"4"}},{"id":1045020,"issuer":{"id":5748,"kind":"organization","name":"DEEP FISSION, INC."},"owners":[{"id":61804,"kind":"person","name":"Muller Richard","position":1,"cik":"0002081872","reported_name":"Muller Richard","relationship":{"director":true,"officer":true,"ten_percent_owner":false,"other":false,"officer_title":"Chief Technology Officer"}}],"security":"Common Stock","published_at":"2025-09-09T17:43:39.000Z","date":"2025-09-05","kind":"grant","planned":false,"acquired":true,"shares":5196426,"ownership":{"direct":true},"footnotes":[{"field":"price","element":"transactionPricePerShare","label":"F1","text":"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."}],"balance_after":5196426,"source":{"system":"sec-edgar","filing":"0001415889-25-023996","document":"form4-09092025_090935.xml","document_sequence":1,"table":"nonDerivative","row_type":"transaction","position":1,"url":"https://www.sec.gov/Archives/edgar/data/2081872/000141588925023996/form4-09092025_090935.xml","form_type":"4"}}]}