Proxima Fusion raised €411M ($468M) at a €2.4B valuation led by XTX Ventures and East X Ventures, with Google joining as a first-time fusion investor. That's the short answer. The longer answer is more interesting.
The Munich-based stellarator startup announced the round on July 7, 2026, calling it the largest private fusion financing in European history. What makes it more than a big number: Google — a company whose AI data centers are straining power grids across three continents — just made its first-ever direct bet on a fusion energy developer, alongside German utility RWE, which is repurposing one of its own retiring nuclear fission sites for Proxima's eventual power plant.
Proxima Fusion €411M Round: Terms and Lead Investors
Proxima Fusion raised €411 million ($468 million) at a €2.4 billion ($2.7 billion) post-money valuation, co-led by XTX Ventures and East X Ventures. Google and RWE joined as new strategic investors, alongside KfW Capital, Germany's state-backed SPRIND deep-tech agency, and Burda Principal Investments. Returning backers include Plural, UVC Partners, Balderton, Cherry Ventures, DST Global Partners, Brevan Howard Macro Venture, Lightspeed, and the EIC Fund — a list that spans European and American venture, sovereign-linked, and family-office capital.
Figures from Proxima Fusion's press release, CNBC, and Sifted reporting as of July 7, 2026.
Why Google Just Made Its First Fusion Bet
Google doesn't make symbolic investments in energy infrastructure it doesn't need. The company has already signed power-purchase and offtake-style agreements with next-generation nuclear fission developers and geothermal startups to feed its data center buildout — the same buildout that's driving the AI infrastructure valuations I've covered in Crusoe's reported $30B round. Proxima is the first fusion name on that list, which matters less for 2026 economics and more as a signal of where hyperscaler capital thinks the power curve bends next.
AI data center electricity demand is compounding faster than grid interconnection queues can clear, pushing hyperscalers to fund power sources years or decades before they're needed rather than wait and buy on the spot market
Fusion offers a theoretical endgame that fission, solar, and gas peakers don't: dense, continuous, low-carbon baseload power with no meltdown risk and no long-lived waste stream — attractive optionality even at a decade-plus time horizon
Strategic investments like Google's buy access and information rights, not just financial upside — a seat at the table if Proxima's Alpha demonstrator proves the physics works at net-energy scale
RWE's participation is the more immediate signal: it's not a financial investor chasing upside, it's a utility repurposing a retiring nuclear fission site in Gundremmingen, Bavaria for Proxima's planned commercial plant, which only happens if RWE's engineers believe the timeline is real
Stellarators vs. Tokamaks: The Bet Behind the Bet
Most fusion capital in the US has flowed to tokamak developers like Commonwealth Fusion Systems, which use a simpler donut-shaped magnetic confinement design that's been studied since the 1950s. Proxima went the harder route: a stellarator, which twists its magnetic coils into a far more complex shape that's brutal to engineer and simulate, but — in theory — can run in continuous steady-state operation rather than the pulsed cycles tokamaks typically need. For a commercial power plant that has to generate baseload electricity around the clock, steady-state operation isn't a nice-to-have, it's close to the whole point.
The money is going toward Alpha, a net-energy stellarator demonstrator under construction near Munich in partnership with the Max Planck Institute for Plasma Physics — the same institute that's run Germany's Wendelstein 7-X stellarator research program for over a decade — and the state of Bavaria. Alpha is the proof point Proxima needs before attempting a full commercial plant later in the 2030s, planned for the RWE-owned former nuclear fission site in Gundremmingen.
Proxima's Funding Trajectory
| Round | Date | Amount | Valuation |
|---|---|---|---|
| Series A | 2024 | €130M | Not disclosed |
| New Round | Jul 2026 | €411M | €2.4B |
Figures from Proxima Fusion's press release and FinSMEs, as of July 7, 2026.
Proxima vs. the Global Fusion Field
At €2.4 billion, Proxima becomes the best-funded fusion company in Europe by a wide margin — but it's still a distant second globally. Commonwealth Fusion Systems, the MIT spinout building a tokamak in Massachusetts, has raised well over $2 billion across multiple rounds and carries a valuation north of $10 billion after backing from Nvidia, Google, and Bill Gates's Breakthrough Energy. TAE Technologies and Helion Energy round out the small group of fusion developers that have crossed into billion-dollar valuation territory.
What sets Proxima apart isn't the check size — it's the density of strategic, non-financial backers in one round. Google, RWE, KfW Capital, and Germany's SPRIND agency aren't chasing a quick markup; they're each buying a specific hedge — Google on future power supply, RWE on repurposing stranded fission assets, and the German state on keeping a frontier energy technology anchored domestically rather than losing it to the US fusion cluster around Boston and the Bay Area.
What to Watch Next
Alpha demonstrator milestones
Proxima's entire valuation rests on Alpha proving net-energy stellarator physics works outside a national lab. Watch for construction updates and first-plasma timelines out of the Munich site.
Google's next move
This is Google's first fusion check. Watch whether it follows with a power-purchase agreement for Proxima's eventual Gundremmingen plant, mirroring its existing deals with fission and geothermal developers.
RWE site conversion
Repurposing a retiring nuclear fission site for fusion is a rare full-circle move in European energy. Watch for regulatory and permitting news out of Bavaria as the Gundremmingen plans firm up.
US-Europe fusion capital gap
Commonwealth Fusion Systems still holds a multi-billion-dollar valuation lead. Watch whether Proxima's round pulls more US megafund capital into European fusion, or whether the gap keeps widening.
For more on the capital pouring into next-generation power to feed AI's appetite, see AI Data Center Power Demand 2026 and Standard Nuclear's S-1 Breakdown. Track private AI and infrastructure valuations on the AI Valuations dashboard at Value Add VC.
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