Antares Raises $470M to Build Military Nuclear Reactors
28 Jul 2026
Advanced nuclear startup Antares has raised a $470 million Series C — split into $370 million in equity and $100 million in debt — to build small modular reactors (SMRs) aimed at powering U.S. military installations. The round was led by Paradigm and Caffeinated Capital, with participation from Industrious Ventures, Point72 Ventures, and Shine Capital.
The raise comes just months after Antares closed a $96 million Series B in December, bringing its total funding to date to $604 million, according to PitchBook.
What Antares is building
Antares's SMR is designed to produce between 100 kilowatts and 1 megawatt of electricity — enough to power up to 750 homes. On June 4, the company's demonstration reactor, the Mark-0, reached criticality at Idaho National Laboratory, a milestone in validating the technology ahead of commercial deployment.
Antares is one of three finalists in the Pentagon's Advanced Nuclear Power for Installations program, which will test SMRs on Air Force bases in Colorado and Montana. The company aims to bring its first electricity-producing reactor online next year, with deployments at U.S. military installations planned for 2028.
A crowded, well-capitalized field
Antares isn't alone in chasing the SMR opportunity. X-energy raised $1 billion through an IPO in April, and Radiant Energy, Standard Nuclear, and Last Energy have each closed nine-figure rounds since December. Industry-wide, Lazard expects new SMRs to cost about $214 per megawatt hour, and the first SMRs across the sector are expected to enter service in the early 2030s.
Being named a Pentagon finalist does not guarantee Antares wins the program over its two competitors, and the company still faces sector-wide hurdles: an immature U.S. supply chain and the technical challenge of scaling SMR production remain unresolved risks for the industry as a whole.
What's missing from this picture
The report does not disclose a valuation for Antares's Series C, nor does it detail how Antares's technology or timeline stacks up directly against its two Pentagon finalist rivals. There's also no information on the company's NRC licensing status, per-unit reactor costs, headcount, manufacturing capacity, or supply chain partnerships — all of which would help clarify how close Antares is to commercial-scale delivery.
Why founders should care
This raise likely signals that investors are increasingly willing to back capital-intensive, defense-adjacent hardware startups, even without a disclosed valuation or full regulatory clarity. For deep-tech founders, Antares's position as a Pentagon program finalist suggests government contracts may plausibly serve as a viable early revenue path — though selection as a finalist is no guarantee of a contract win, as the risks section makes clear.
The clustering of nine-figure rounds across Antares, X-energy, Radiant Energy, Standard Nuclear, and Last Energy since December suggests the SMR sector may be entering a more competitive, possibly frothier, funding phase. Founders in adjacent hardware or infrastructure categories should watch whether this pace of capital deployment persists or cools.
Antares's use of debt alongside equity ($100 million of the $370 million total) may also point to alternative capital structures becoming more available for infrastructure-heavy startups — a structure worth considering for founders building capital-intensive hardware rather than pure software.
Finally, the sector-wide risks flagged here — an immature supply chain and production scaling challenges — are a reminder that hardware founders in capital-intensive fields should probably build operational risk planning into their roadmaps early, rather than treating funding milestones as a proxy for commercialization readiness.