As global energy demand continues to surge, driven by both rising household consumption and fast-expanding AI infrastructure, startup investors are increasingly turning to nuclear fusion and fission startups to supply our power-hungry era.
They’re not afraid to write big checks either. The latest evidence of this was a $450 million Series A that Livermore, California-based fusion power startup Inertia Enterprises announced Wednesday.
Bessemer Venture Partners led the round for the 2-year-old company, joined by Google Ventures, Threshold and other backers. Inertia plans to use the funds toward a fusion pilot at Lawrence Livermore National Laboratory, which will involve building the world’s most powerful laser and a production line to mass manufacture fuel targets.
The financing is the latest in a string of recent, very large deals around both fusion and nuclear fission. Per Crunchbase data, both funding and deal volume for the space hit a high last year, and 2026 is off to a promising start as well.
Headline deals, leading fundraisers
It’s mostly funding announcements, but not exclusively. On the fusion front, the highest profile recently proposed deal was Trump Media & Technology Group’s surprising announcement in December that it plans to combine with fusion company TAE Technologies in what TMTG called a stock transaction valued at more than $6 billion.
The deal is a long time coming for TAE, which was founded in 1998 and is the oldest operating venture-backed fusion energy company in the Crunchbase dataset. The company has seen at least $1.5 billion in prior known funding to date.
Other fusion companies have also been prodigious fundraisers. The leader is Commonwealth Fusion Systems, with $2.86 billion in equity funding, while other standouts include Helion Energy ($1 billion), Pacific Fusion ($900 million) and General Fusion ($357 million).
Nuclear fission is another hot area for investment, with over $2.5 billion in funding last year, per Crunchbase. The largest deal was a $700 million Series D in late November for X-energy, a developer of advanced nuclear reactor and fuel technology.
Activity looks to be accelerating further this year, with more than $270 million in funding, including a $140 million round two weeks ago for Tennessee-based Standard Nuclear, which manufactures advanced nuclear fuel for new reactors.
Public markets too
Public investors also appear receptive. Oklo, which develops nuclear reactors, went public in 2024 through a merger with a SPAC launched by Sam Altman. It’s down quite a bit from the height scaled late last year, but still had a recent market cap around $10 billion.
Other SPAC deals have also popped up, including One Nuclear Energy, which wants to develop energy parks with small modular reactors to meet data center demand, and Hadron Energy, a developer of light-water micro-modular reactors. Meanwhile Terrestrial Energy, a developer of small modular nuclear plants, completed a SPAC merger in October.
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Illustration: Dom Guzman
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