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. Related Crunchbase query: Nuclear Energy-Related Startup Funding, 2025 Related reading: A Little Background On Fusion Funding And TAE Technologies, The Company Merging With Trump Media Fusion Startup Helion Powers Up With $425M Series F Nuclear Fission Shows Continuing Popularity (With VCs, At Least) Cleantech’s Rough Year Ends On An Up Note Bill Gates-Founded Nuclear Energy Startup Raises $650M From Nvidia’s VC Arm, Others Fusion Funding Has Fizzled Illustration: Dom Guzman