Proxima Fusion funding round hits €411 million

Proxima’s new capital is meant to industrialize exactly this kind of complexity, moving coil production from single prototypes to Alpha-scale volumes

(Image courtesy of Proxima)

Proxima Fusion has closed a €411 million ($468 million) financing round, the largest private investment in European fusion history, pushing the German stellarator developer to a €2.4 billion valuation. For engineers and procurement teams tracking Europe’s fusion supply chain, the Proxima Fusion funding round matters less for its headline size than for where the capital is earmarked, magnet production, superconducting cable manufacturing, and completion of a demonstrator coil that has to work before Alpha can proceed.

Inside the Proxima Fusion funding round

XTX Ventures and East X Ventures led the round, joined by RWE and Google as strategic investors alongside a broader syndicate of returning and new backers. RWE joined as a strategic investor without disclosing the size of its individual stake, a detail that matters less than the Gundremmingen site partnership sitting alongside it. Proxima says the deal marks Google’s first direct investment in a European fusion company, extending a portfolio that already includes an offtake agreement with Commonwealth Fusion Systems and a decade-plus backing of TAE Technologies in the United States.

What the financing round buys on the ground

The proceeds fund completion of the Stellarator Model Coil, expansion of high-temperature superconducting cable and magnet production, and further build-out of the engineering and manufacturing systems stellarators require. Proxima is expanding its engineering and technical teams across its sites in Germany, Switzerland, and the UK, industrial scaling that follows the MoU signed with Bavaria, RWE, and the Max Planck Institute for Plasma Physics earlier in 2026. The round was structured to trigger Bavaria’s €400 million public commitment agreed under that framework, and Proxima states the condition has now been met, a signal that targeted public funding can pull private capital in at scale rather than substitute for it.

The stellarator case against tokamak scaling

Proxima’s QI-HTS stellarator design avoids the plasma confinement instabilities that come from the large internal currents tokamaks rely on, and the company argues this lets a stellarator run continuously where a tokamak like CFS’s SPARC must operate in pulses. Proxima calls Stellaris, its commercial design, the first peer-reviewed stellarator power plant concept to integrate physics, engineering, and maintenance from the outset. Google backing both a stellarator and a beam-driven, hydrogen-boron approach at TAE suggests the company is hedging across confinement architectures rather than picking a single technical winner.

How Proxima stacks up against its competitors

Public reporting puts Commonwealth Fusion Systems’ cumulative funding near $3 billion as it works toward net-energy gain with its tokamak, while Helion Energy has raised hundreds of millions at multi-billion-dollar valuations and is advancing a commercial plant in the US. Germany’s own Marvel Fusion, working with lasers rather than magnetic confinement, has reportedly raised close to €400 million. At €2.4 billion, Proxima now sits ahead of every other European fusion company on valuation, though it still holds a fraction of CFS’s total capital.

Proxima Fusion co-founder and CEO Francesco Sciortino framed the round as proof that “Europe is racing with the United States and China” toward the first commercial fusion plant, and the next markers will be concrete rather than financial: whether the Stellarator Model Coil completes on schedule, and whether Alpha, slated to begin operations around 2031, can demonstrate net energy gain in the early 2030s. Gundremmingen is where Proxima intends to build Stellaris after that, on the same site RWE once ran as a fission plant, a succession that will say more about commercial fusion’s readiness than any funding total.

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