Proxima Fusion has raised €411m at a €2.4bn valuation, making the Munich-based startup Europe's first fusion energy unicorn.
The round is the largest private investment ever in a European fusion company. It also makes Proxima the best-funded fusion startup on the continent.
XTX Ventures, the venture arm of trading firm XTX Markets, and fusion-focused fund East X Ventures led the round. Google and RWE joined as strategic investors.
RWE's investment comes just months after the utility signed an agreement with Proxima to build the world's first commercial stellarator fusion power plant on the site of a former nuclear fission plant in Gundremmingen, Bavaria.
KfW Capital, SPRIND and Burda Principal Investments also participated, alongside returning backers including Plural, Balderton, Cherry Ventures, Lightspeed, UVC Partners, redalpine, CDP Venture Capital, Bayern Kapital, and the EIC Fund.
The record round cements Proxima's status as Europe's homegrown fusion champion, a role co-founder and CEO Francesco Sciortino has long insisted the company will never trade for a US postcode.
"We are not playing around with the idea of running away to San Francisco," he recently told Impact Loop in an interview. "It is in our DNA that we are here to build this thing."
The deal marks Google's first investment in a European fusion company. The tech giant already backs US fusion firms Commonwealth Fusion Systems and TAE Technologies, and has signed an off-take agreement to buy power from Commonwealth's first commercial plant.
The team at Proxima Fusion with a 3D render of its fusion energy reactor in the background. Credit: Proxima Fusion
Proxima spun out of the Max Planck Institute for Plasma Physics in 2023. The startup is developing stellarators, machines that use powerful magnets to confine superheated plasma and replicate the reaction that powers the Sun.
The fresh capital will fund Alpha, Proxima's demonstration stellarator near Munich, which targets net energy gain in the early 2030s. A commercial power plant, Stellaris, is slated to follow later that decade.
Sciortino recently sat down with Impact Loop to discuss how Europe should fund 'civilisation-changing' green projects. His thesis, that targeted public money should catalyse private capital rather than pick winners, now has a proof point on his own cap table.
In under three years, Proxima has secured more than €650m, including €95m in public grants.
The raise lands as Europe's fusion founders push Brussels for a coherent strategy on the technology. Sciortino was among the CEOs who signed an open letter to the EU earlier this year calling for milestone-based funding and a regulatory framework that separates fusion from nuclear fission.
The EU is expected to publish its long-delayed fusion strategy this summer.
Even with the record round, Europe trails the US on fusion capital.
Commonwealth Fusion Systems has raised $2.9bn to date, per Dealroom data, while Sam Altman-backed Helion Energy secured $465m in June at a $15.5bn valuation.
Proxima employs around 200 people across Munich, Zurich and Oxford. The company says it is now hiring across engineering, manufacturing and operations as it pursues a vertical integration strategy, following the recent appointment of a heavyweight industrial board including former EDF boss Luc Rémont and ex-Breakthrough Energy VP Ann Mettler, whom Impact Loop interviewed last month.