Deep Fission, Inc. Common Stock (FISN)

About Deep Fission, Inc. Common Stock

Deep Fission Inc is a nuclear energy technology company developing a small modular reactor based on established pressurized water reactor technology, with novel emplacement in deep boreholes approximately one mile below the Earth's surface. Its reactor, which is referred to as the Gravity Reactor, will leverage subsurface conditions to support key containment and operating functions, including the use of hydrostatic pressure from a water column within the borehole to support reactor operating pressure and cooling, and the surrounding geological formation to provide structural confinement and shielding. The group's focus is within the United States, where electricity demand growth, expanding digital infrastructure, and evolving energy policy.

Institutional ownership

In 13F filings for the quarter ended June 30, 2026, 23 institutions reported holding FISN, with 2.3 million shares worth $25.4 million in aggregate. The largest reported holder was Blue Owl Capital Holdings, with 1.3 million shares worth $14.7 million. Of the 5 largest holders listed below, all 5 opened new positions in FISN during the quarter.

Form 13F is a quarterly report that institutional investment managers with at least $100 million in qualifying securities file with the SEC. It lists long positions as of the last day of the quarter and is due within 45 days of quarter end, so these holdings describe that date rather than today.

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