Deep Fission, Inc. - Common Stock (FISN)

Deep Fission, Inc. (Nasdaq: FISN) (“Deep Fission” or the “Company”), an advanced nuclear energy company developing small modular pressurized water reactors installed one mile underground, today announced that the U.S. Department of Energy (DOE), has approved the company's Nuclear Safety Design Agreement (NSDA) for its Gravity™ Nuclear Reactor. This marks a major regulatory milestone, confirming that Deep Fission's reactor design warrants advancement under the Department of Energy’s Reactor Pilot Program.

Deep Fission, Inc. (Nasdaq: FISN) (“Deep Fission” or the “Company”), an advanced nuclear energy company developing small modular pressurized water reactors deployed one mile underground, today announced that Liz Muller, Co-Founder and CEO of Deep Fission, will present at Canaccord Genuity’s 46th Annual Growth Conference in Boston, MA on Tuesday, August 11, 2026 at 1:30 p.m. ET.

Deep Fission, Inc. (Nasdaq: FISN) (“Deep Fission” or the “Company”), an advanced nuclear energy company developing small modular pressurized water reactors installed one mile underground, today announced the arrival of its prototype reactor canister at its Parsons, Kansas site, marking a key milestone in the Company’s Proof-of-Concept Well program and its Gravity Nuclear Reactor™ development. In celebration of this milestone and its listing on the Nasdaq Stock Market, Deep Fission will ring the Nasdaq closing bell today at 4:00 PM ET.

Deep Fission, Inc. (Nasdaq: FISN) (“Deep Fission” or the “Company”), an advanced nuclear energy company developing small modular pressurized water reactors installed one mile underground, will participate in the Golden Era of Nuclear Power event at Idaho National Laboratory’s (INL) Materials and Fuels Complex in Idaho Falls, Idaho on Thursday, June 25.

Deep Fission, Inc. (Nasdaq: FISN) (“Deep Fission” or the “Company”), an advanced nuclear energy company developing small modular pressurized water reactors installed one mile underground, today announced it has signed Letters of Intent (LOIs) with data centers, co-developers, industrial parks, and strategic partners representing up to 18.5 gigawatts (GW) of potential generation capacity.

Deep Fission, Inc. (Nasdaq: FISN) (“Deep Fission” or the “Company”), an advanced nuclear energy company developing small modular pressurized water reactors installed one mile underground, today announced the closing of its public offering of 2,500,000 shares of its common stock at a public offering price of $16.00 per share, for total gross proceeds of $40 million, before deducting underwriting discounts and commissions and other offering expenses payable by the Company. In addition, Deep Fission has granted the underwriters a 30-day option to purchase up to an additional 375,000 shares of its common stock at the initial public offering price, less underwriting discounts and commissions. The Company’s common stock began trading on Nasdaq Global Market under the symbol “FISN” on June 18, 2026.