Deep Fission, Inc. the advanced nuclear energy company developing small modular pressurized water reactors installed one mile underground, including one in southern Kansas, announced that it has commenced the roadshow for its proposed underwritten public offering of 6,000,000 shares of its common stock.
Deep Fission filed with the SEC last week for a $150 million public listing targeting a valuation of up to $1.66 billion. In addition, Deep Fission intends to grant the underwriters a 30-day option to purchase up to an additional 900,000 shares of its common stock at the initial public offering price, less underwriting discounts and commissions. The initial public offering price is expected to be between $24.00 and $26.00 per share. The Company has applied to list its common stock on The Nasdaq Global Market under the ticker symbol “FISN”.
Deep Fission intends to use the net proceeds from this offering for general working capital and corporate purposes, including towards the engineering, research and development, licensing and construction of its first pilot nuclear reactor and related technologies.
William Blair, Stifel, and Canaccord Genuity are acting as joint lead book-running managers for the offering. Seaport Global Securities and Benchmark, a StoneX Company are acting as bookrunners for the offering.
Deep Fission is constructing the world’s first 1-mile deep underground nuclear reactor at the Great Plains Industrial Park in Parsons, Kansas. The California-based startup broke ground on the $80-million pilot project in December 2025 and is actively drilling test wells to demonstrate its novel “Gravity” microreactor technology.
The company CEO, Liz Muller told NPR affiliate KCUR the company will not consume large amounts of water, a worry and concern often voiced by opponents and critics of data centers.
Instead, Deep Fision has a partnership with Endeavor, parent company of Edge, a firm that manufactures waterless data centers. Muller also says any radioactive waste from the plant would remain underground and “billions of tons of rock.”
In a press release, Deep Fission stated that Parsons offers the opportunity to “potentially grow the Park for decades to come.”
Muller founded Deep Fission in 2023 with her father, University of California, Berkeley professor emeritus of physics Rich Muller. The idea behind the company is to drill 30-inch-wide, mile-deep holes and place small nuclear reactors at the bottom. Water will be placed in the holes, where it will turn to steam and rise to turn turbines, generating energy. The water will then cool and return to the hole for reuse.
A registration statement relating to these securities has been filed with the Securities and Exchange Commission but has not yet become effective. These securities may not be sold, nor may offers to buy be accepted, prior to the time the registration statement becomes effective. The proposed offering will be made only by means of a prospectus. Copies of the preliminary prospectus relating to the proposed offering may be obtained, when available, from William Blair & Company, L.L.C., Attention: Prospectus Department, 150 North Riverside Plaza, Chicago, IL 60606, by telephone at (800) 621-0687, or by email at prospectus@williamblair.com, Stifel, Nicolaus & Company, Incorporated, Attention: Prospectus Department, One Montgomery Street, Suite 3700, San Francisco, CA 94104, by telephone at (415) 364-2720 or by email at syndprospectus@stifel.com, and Canaccord Genuity LLC, Attention: Syndication Department, One Post Office Square, Suite 3000, Boston, Massachusetts 02109, or by telephone at (617) 371-3900, or by email at prospectus@cgf.com.
