About Antares
Antares Nuclear designs small nuclear reactors, called microreactors, and builds them in its own factory. Its R1 reactor is designed to produce 100 kilowatts to 1 megawatt of electricity for six years or more without refueling. Its first customers are U.S. military bases and space programs that need power far from a reliable grid.
Antares is based in Torrance, California, and has sites in Idaho Falls, Idaho, and Aiken, South Carolina. Its Mark-0 test reactor first sustained a nuclear chain reaction at Idaho National Laboratory on June 4, 2026. The Army picked Antares to build and run reactors at Fort Bragg, and the Air Force chose it for a proposed reactor at Joint Base San Antonio. Co-founder Jordan Bramble is CEO. Antares has raised more than $600 million.
Funding Rounds (SEC Form D)
| First sale | Filed with SEC | Amount sold | Investors | Avg. check | Terms | Filing |
|---|---|---|---|---|---|---|
| Aug 3, 2026 | Aug 18, 2026 | $59,999,682of $84.9M target | 13 | $4.6M | EquityRule 506(b) | Form D ↗ |
| Jul 8, 2026 | Jul 28, 2026 | $319,999,537fully sold | 24 | $13.3M | EquityRule 506(b) | Form D ↗ |
| Sep 10, 2025 | Sep 19, 2025 | $51,045,266of $79.5M target | 31 | $1.6M | Equity, OptionsRule 506(b) | Form D ↗ |
| Sep 24, 2024 | Oct 9, 2024 | $27,529,968fully sold | 10 | $2.7M | Equity, OptionsRule 506(b) | Form D ↗ |
| Oct 13, 2023 | Oct 30, 2023 | $8,116,498of $8.1M target | 44 | $184K | Equity, OptionsRule 506(b) | Form D ↗ |
| Total, five offerings | $466,690,951 | |||||
First sale is the date the first investor in the offering committed to invest. Companies must file Form D within 15 days of that date, so filing dates run later.
Rounds announced by Antares
What the company said publicly about its funding. Announced amounts can differ from Form D figures: an announcement can combine several closings, and some money is raised without a Form D.
| Announced | Round | Amount | Investors | Source |
|---|---|---|---|---|
| Jul 27, 2026 | Series C | $470M | Paradigm and Caffeinated Capital (co-leads), Point72 Ventures, Shine Capital, Industrious Ventures | antaresindustries.com ↗ Press release ↗ |
| Dec 2, 2025 | Series B | $96M | Shine Capital (lead), Alt Capital, Caffeinated, FiftyThree Stations, Industrious | antaresindustries.com ↗ Press release ↗ TechCrunch ↗ |
| Oct 30, 2024 | Series A | $30M | Alt Cap and Caffeinated Capital (co-leads), Rogue, Uncommon Capital, Shrug, Banter Capital, Box Group, Shine Capital | antaresindustries.com ↗ |
| Oct 31, 2023 | Seed | $8M | Caffeinated Capital (lead), Humba Ventures, Pathbreaker, Rogue VC, Shrug, Uncommon Capital, angel investors | antaresindustries.com ↗ antaresindustries.com ↗ |
Why Investors Backed Antares
Investors put money into Antares because it has met hard nuclear deadlines. Its Mark-0 test reactor went critical in Idaho on June 4, 2026, the first under a fast-track Energy Department program. Less than two months later, Paradigm and Caffeinated Capital co-led a $470 million Series C. Antares also says it now holds contracts with the Army, the Air Force and the Space Force.
The problem it targets
Many U.S. military bases draw their power from the commercial grid. Antares's case is that the grid is under strain from rising demand, extreme weather and targeting by adversaries. The liquid-fuel supply chains behind diesel generators are also vulnerable. The government has set a deadline, too. Executive Order 14299 directs the military to run a reactor at a domestic base by September 30, 2028. CEO Jordan Bramble also argues that for nearly 50 years, U.S. nuclear engineering focused on paperwork and modeling instead of building hardware.
What the product does
The R1 microreactor is designed to make 100 kilowatts to 1 megawatt of electricity for six years or more. Its TRISO fuel sits in a graphite core. Sodium heat pipes carry the heat away passively, and a closed nitrogen Brayton cycle turns that heat into electricity. Antares machines its own nuclear-grade graphite at its Torrance factory, Antares Prime. A space version, the R1-S, will get a nuclear ground test and then join a spacecraft for flight certification.
Progress so far
Mark-0 reached criticality at Idaho National Laboratory on June 4, 2026. In April 2026, the Air Force picked Antares for a proposed reactor at Joint Base San Antonio. In August, the Army chose it to build, own and operate reactors at Fort Bragg. Bramble then said its Army, Air Force and Space Force contracts were worth "on the order of $1B." In September, it won a $161 million defense award to demonstrate a space reactor. On October 23, the Energy Department approved the safety design agreement for Mark-1, its first power-producing reactor.
Who backs it
Caffeinated Capital led the $8 million seed round in 2023 and has joined every round since. Alt Cap and Caffeinated co-led the $30 million Series A in October 2024, and Alt Cap's Jack Altman joined the board. Shine Capital led the $96 million Series B in December 2025, and Shine general partner Alex Hartz is a director. Paradigm and Caffeinated then co-led the $470 million Series C in July 2026, with Point72 Ventures, Shine and Industrious Ventures. Paradigm managing partner Alana Palmedo also sits on the board.
How the market is moving
Washington is pushing small reactors hard. A May 2025 executive order told the Energy Department to get at least three test reactors critical by July 4, 2026. Rivals moved fast. Valar Atomics became the second to go critical in June, and Aalo Atomics the fourth by July 4, POWER reported. In August 2026, the Army picked five Janus vendors: Antares, BWXT, General Atomics, Radiant and Westinghouse. Private money keeps coming as well. X-energy raised $1 billion in an April 2026 IPO, according to TechCrunch, and Radiant raised more than $300 million in December 2025.
We wrote this summary from public statements by Antares and its investors. It is not investment advice.
Antares in the News
- Antares Wins $161M Award for Space Nuclear Power
- Exclusive: Why Antares is bringing nuclear power to Fort Bragg
- Antares raises $470M to build nuclear reactors for the US military
- Antares Mark-0 Becomes First Advanced Nuclear Reactor to Achieve Criticality Under DOE Pilot Program
- Nuclear Startup Antares Wins Key Approval Through DOE Program
- Who's Who in Tech: Antares Working on Nuclear Solution
Leadership Team
Executive officers and directors listed on Antares's Form D filed Aug 18, 2026.
Sources
- SECAntares Nuclear, Inc. filing history
- Companyantaresindustries.com, leadership team
- Companyantaresindustries.com, Mark-0 criticality (2026-06-04)
- Companyantaresindustries.com, Air Force ANPI selection (2026-04-22)
- Companyantaresindustries.com, Army Janus award (2026-08-26)
- Companyantaresindustries.com, $161M space reactor award (2026-09-11)
- Companyantaresindustries.com, Mark-1 safety agreement (2026-10-23)
- Companyantaresindustries.com, Rian Bahran joins as CNO (2026-07-28)
- Companyantaresindustries.com, co-founders podcast post (2024-01-30)
- Companyantaresindustries.com, Urenco HALEU agreement (2026-05-21)
- PressPOWER Magazine, Series B release text (2025-12-03)
- PressPOWER Magazine, Valar Atomics second to go critical (2026-06-19)
- PressPOWER Magazine, Aalo Atomics fourth by July 4 (2026-07-06)
- PressAmerican Nuclear Society, Army Janus vendors (2026-08-28)
- PressAmerican Nuclear Society, Air Force ANPI selections (2026-04-23)
- PressSiliconANGLE, Radiant raises $300M (2025-12-18)
- Investorparadigm.xyz, Alana Palmedo bio (board of Antares)
- Investorshine.vc, team page (Alex Hartz, General Partner)