Deep Fission, which develops small modular nuclear reactors deployed in deep underground shafts, filed on Wednesday with the SEC to raise up to $150 million in an initial public offering.
The company plans to raise $150 million by offering 6 million shares at a price range of $24 to $26. At the midpoint of the proposed range, Deep Fission would command a fully diluted market value of $1.7 billion.
Deep Fission is a nuclear energy technology company developing a small modular reactor based on pressurized water reactor technology. The company's reactor, called the Gravity Reactor, is designed to be installed approximately one mile below the Earth's surface, where subsurface conditions, including hydrostatic pressure from a water column and the surrounding geological formation, are intended to support containment, cooling, and shielding functions. The approach aims to reduce reliance on the large surface infrastructure associated with conventional nuclear plants, with the potential for lower capital costs, faster deployment, and improved security. Reactors may be deployed individually or in clustered configurations at a single site. Deep Fission has not generated any revenues to date.
The Berkeley, CA-based company was founded in 2023. It plans to list on the Nasdaq under the symbol FISN. Deep Fission filed confidentially on April 22, 2026. William Blair, Stifel, Canaccord Genuity, The Benchmark Company, and Seaport Global are the joint bookrunners on the deal.
