Analysis
Munich-based Proxima Fusion raised €411 million (roughly $468 million) in a round that values the stellarator-fusion startup at €2.4 billion (~$2.7 billion), the largest single funding round for a fusion company in European history. The round was led by XTX Ventures and East X Ventures, with Google and German utility RWE joining as strategic investors alongside KfW Capital, SPRIND, and returning backers including Plural, Balderton, Lightspeed and Cherry Ventures.
Founded in 2023 as a spinout of Germany's Max Planck Institute for Plasma Physics, Proxima has now raised more than €650 million in under three years, including €95 million in public grants -- a capital structure that leans more heavily on government and strategic money than most venture-backed hardware bets. The company is building Alpha, a net-energy stellarator demonstrator targeted for the early 2030s, which it positions as the precursor to Stellaris, its planned first commercial stellarator power plant later in the decade.
Proxima's stellarator approach -- which uses a twisted magnetic-confinement geometry rather than the donut-shaped tokamak favored by rivals like Commonwealth Fusion Systems and TAE Technologies -- has historically been seen as harder to engineer but more stable to operate once built. Google's direct investment follows its existing pattern of financing next-generation power generation, including geothermal and small modular nuclear deals, as it looks to secure firm, carbon-free power for AI data centers years before those plants can realistically come online.
A €2.4 billion valuation for a company that hasn't yet built a net-energy reactor puts Proxima roughly in the same tier as Commonwealth Fusion Systems' last private marks, even though CFS has a multi-year head start and a $1.8 billion round of its own under its belt. The gap says less about the technology and more about how much capital fusion can now absorb given AI-driven power demand -- Quaise Energy's geothermal round the same week is the other side of that same trade.
For energy-focused GPs, the read is that fusion has quietly moved from a moonshot line item to a strategic-capital category, with hyperscalers now writing checks directly rather than just signing power-purchase agreements. For founders in adjacent hard-tech categories, Proxima's grant-heavy capital stack is a template: public money can de-risk the earliest, most capital-intensive stages in a way pure venture capital structurally can't.
