Antares has raised $470 million in Series C funding, co-led by Paradigm and Caffeinated Capital, with participation from Point72 Ventures, Shine Capital, Industrious Ventures, and others. The round accelerates Antares' path from a demonstrated reactor to fielded power systems for defense and space, with initial deployments to U.S. military installations beginning by 2028.
"Jordan and the Antares team just achieved the first private advanced reactor criticality in decades with a factory built microreactor,” said Alana Palmedo, managing partner, Paradigm. “Now they transition to a new era: The scaled deployment of microreactors that can operate reliably, safely, and economically for years on U.S. military bases. Paradigm is thrilled to back this team as they help to restore energy dominance in the U.S."
The capital, which includes $370 million in equity and $100 million in debt, comes weeks after Antares took its Mark-0 reactor critical at Idaho National Laboratory. It was the first privately developed non-light-water reactor to achieve criticality in the United States in more than four decades. Antares met the milestone on schedule, validating reactor physics, reactivity control, and instrumentation in a full-scale core using TRISO fuel.
“Instead of relying on hype, Antares stands apart in the advanced nuclear space by delivering concrete results, such as winning the race to criticality and securing major customers like the U.S. Air Force,” said Varun Gupta, Partner, Caffeinated. “These results are not a product of luck; they are the product of outstanding decisions Jordan and the Antares team have consistently made, including their reactor design, choice of fuel, and focus on the Department of War as a first customer—decisions that ensure both reactor safety and the speed and resiliency of their supply chain.”
The company's microreactors are designed to run safely and autonomously for years without refueling, delivering uninterrupted power to the customers who depend on it most. That focus — engineering for sustained operation, not a one-time demonstration — shapes every decision the company makes.
"On June 4th, we won the race to criticality, and now we’ve shifted to the race to commercialization," said Jordan Bramble, CEO and co-founder of Antares. "The military has been a partner to us every step of the way. We’ve secured firm contracts to build reactors. To do that, we’re announcing $470M of equity and debt to invest one-to-one with the taxpayer in bringing this technology to commercial scale. Our deep customer relationships and committed orderbook allow us to focus our engineering roadmap on one simple thing from here on out - reactors that operate reliably and safely for 6+ years deployed to military installations as soon as 2028. This focus will guide us to the first microreactor producing useful electricity in a truly commercially viable design.”
The Series C funds the path from a demonstrated reactor to fielded systems – the Mark-1 electricity-producing reactor in 2027, and initial deployments to defense customers in 2028, including the U.S. Air Force under the Advanced Nuclear Power for Installations initiative. Antares produces microreactors purpose-designed for those missions, addressing a widening national vulnerability: many U.S. military installations depend on a commercial grid under growing strain from rising demand, extreme weather, and adversary targeting. Antares is building to meet the deadline set out by Executive Order 14299, which directs the Department of War to begin operating a reactor at a domestic military installation by September 30, 2028.