Deep Fission targets $1.66 billion valuation in Nasdaq IPO plan
Deep Fission is asking markets to price underground reactors at a $1.66 billion valuation as drilling starts in Parsons, Kansas. The IPO now tests whether investors will back the concept beyond the pilot stage.
Deep Fission is asking Nasdaq investors to do something unusually hard in nuclear: put a $1.66 billion price tag on a reactor idea built around going a mile underground. The California-based company plans to raise about $156 million in the offering, and it says the money would support working capital, engineering, research and development, licensing, and construction of its first pilot reactor and related technologies.
That makes the listing less like a standard startup capital raise and more like a credibility test. Deep Fission, founded in 2023 by Elizabeth Muller and Richard Muller, is developing small modular pressurized water reactors designed to sit one mile below the surface. The pitch is that depth itself becomes part of the safety and siting case, with surrounding geology acting as a natural barrier and shrinking the surface footprint that usually complicates reactor deployment.
The company has already pushed beyond pure concept work. In March 2026, Deep Fission said it had begun drilling its first data acquisition well in Parsons, Kansas, the first of three planned wells for the pilot site. The well was described as roughly 6,000 feet deep and about eight inches in diameter. For a concept that hinges on subsurface conditions, that drilling campaign is not a side note. It is the data stream that will shape design validation, site characterization, and eventually the licensing file.
Deep Fission is also not trying to move alone. On January 7, 2025, it announced a strategic partnership with Endeavour Energy to co-develop 2 gigawatts of underground nuclear energy for data centers, with the first reactors expected in 2029. Endeavour later said the work was aimed at powering AI-ready data centers, giving the project a commercial customer story that reaches beyond generic advanced-reactor optimism.
Federal support adds another layer. Deep Fission was selected in August 2025 for the U.S. Department of Energy’s Nuclear Reactor Pilot Program, which aims to see at least three advanced reactor concepts reach criticality outside national laboratories by July 4, 2026. Deep Fission and DOE signed an Other Transaction Agreement under that program, and the company says it is targeting criticality by that deadline under DOE oversight. The company also completed a reverse merger with Surfside Acquisition Inc. on September 8, 2025 and raised $30 million in a heavily oversubscribed private placement at $3.00 per share, giving investors a recent reference point for how the market has already priced the story.
That is the backdrop for the IPO: a company with a federal pilot path, a data-center angle, and drilling underway, now asking the public market to decide whether underground nuclear can move from striking concept to bankable deployment. The answer will turn on the same proof points that still hang over the sector, licensing, economics, and schedule, only now with a Nasdaq ticker attached.
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