Deep Fission, Inc.

Deep Fission was founded in 2023 by Elizabeth Muller and Richard A. Muller, who had earlier co-founded Deep Isolation, a company developing deep-borehole disposal of nuclear waste; Deep Fission applies a related deep-borehole approach to power generation. The company emerged from stealth in 2024 with a $4 million pre-seed funding round led by Joe Lonsdale 's venture capital firm 8VC.

In August 2025, the DOE named Deep Fission among the initial projects selected for its Reactor Pilot Program, an initiative created under Executive Order 14301 that uses DOE authority to expedite testing of advanced reactors outside the national laboratories. The following month, the company became an SEC-reporting company through a reverse merger with Surfside Acquisition Inc. and a concurrent $30 million private placement, and in December 2025 it selected the Great Plains Industrial Park in Parsons, Kansas, as its pilot site and held a groundbreaking ceremony.

In early 2026, the company raised $80 million in a private placement and formed a strategic relationship with Blue Owl Capital 's Real Assets platform, whose managed fund participated in the round, with Goldman Sachs acting as the company's financial advisor; it also agreed to purchase low-enriched uranium from Urenco USA for its demonstration and early commercial phases, and in March began drilling its first data-acquisition well at the Kansas site.

In May 2026, Deep Fission filed for an initial public offering on Nasdaq, initially seeking about $157 million at a valuation of roughly $1.66 billion before reducing the offering the following month. The offering priced on June 17, 2026, at $16 per share, the low end of the revised range, raising $40 million in gross proceeds, and the company's shares began trading on the Nasdaq Global Market on June 18, 2026, under the ticker symbol FISN, with Benchmark and Seaport Global as joint book-running managers. In its offering documents, the company disclosed that it had not generated revenue and that its independent auditors had raised substantial doubt about its ability to continue as a going concern.