Proxima Fusion Raises €411M, Becomes Europe's Best-Funded Fusion Company

Proxima Fusion, a Munich-based fusion company, has closed a €411 million Series A2 funding round at a €2.4 billion valuation, making it Europe's best-funded fusion company and marking the largest funding round in European fusion history. XTX Ventures and East X Ventures headed the round. Strategic investors RWE (the German utility) and Google joined, along with KfW Capital, SPRIND (the German government's innovation agency), and Burda Principal Investments. A roster of returning backers also participated, including Balderton Capital, Cherry Ventures, and a dozen other venture firms.

The company, founded in 2023 as a spin-out from the Max Planck Institute for Plasma Physics, develops stellarator technology. This magnetic confinement approach uses external magnets rather than plasma current to contain fusion reactions. Tokamaks, the more widely pursued design, confine plasma in a doughnut shape through internal currents. Stellarators instead shape plasma in a twisted three-dimensional geometry. Proxima is pursuing this less common path, building what it calls its quasi-isodynamic (QI) high-temperature superconducting (HTS) stellarator concept based on decades of Max Planck research.

The capital comes as Proxima accelerates development of two projects: Alpha, a demonstration plant slated for the early 2030s, and Stellaris, the company's design for the world's first commercial fusion power plant, targeted for later in the decade. Both are being built with public and private backing. RWE, one of Europe's largest energy producers, signed an agreement with Proxima months before investing to co-develop the first stellarator fusion power plant at Gundremmingen in Bavaria, a site where a fission reactor was decommissioned.

Private capital meets public commitment

The timing of this round reveals the interplay between public and private backing. Proxima closed the financing just three months after signing a memorandum of understanding with the Bavarian state government, the Max Planck Institute, and RWE. The state committed €400 million to the company's roadmap; the new €411 million private round essentially matched that public pledge. In less than three years, Proxima has now secured over €650 million in total funding, with €95 million of that from public grants and programmes.

This structure, where public investment attracts and validates private capital, appears to have worked. CEO and co-founder Francesco Sciortino said in a statement: "Europe is racing with the US and China to get to the first fusion power plant. Investors recognise both the urgency and the opportunity of what we're doing."

The company's earlier Series A round, worth €130 million in June 2025, was led by Cherry Ventures and Balderton Capital. That smaller round now sits alongside this €411 million close as evidence that venture and growth investors see a credible path to commercial viability in Proxima's approach. Google's participation is particularly noteworthy. The search giant is also an investor in Commonwealth Fusion Systems, a larger American tokamak competitor, and has signed an offtake agreement with CFS for future power. Google's dual backing suggests it believes both stellarators and tokamaks could viably produce clean energy at scale.

Building the team and the machines

Proxima will deploy the capital to expand its footprint across three European cities. The company currently employs about 200 people across Munich, Zurich, and Oxford. New funding will support hiring in engineering, manufacturing, and operations. The company is pursuing what it calls vertical integration: building in-house the complex components and systems needed for stellarators.

Specifically, Proxima plans to complete its Stellarator Model Coil, a full-scale superconducting magnet prototype; expand production of high-temperature superconducting cables and magnets; and develop the engineering and manufacturing systems required to build stellarators at scale. Additive manufacturing (3D printing) features prominently in Proxima's approach: the twisted coil geometries that stellarators require are difficult to machine conventionally, making 3D printing a critical tool for rapid prototyping and manufacturing.

The €411 million round comes against a backdrop of accelerating fusion investment worldwide. American fusion companies have secured far larger total funding pools. Commonwealth Fusion Systems has raised $2.9 billion in total backing, including an $863 million round in August. Helion Energy, another Sam Altman-backed fusion venture, has accumulated $1.5 billion across multiple rounds. By comparison, Proxima's €2.4 billion valuation suggests it is still trailing its best-capitalised American peers in absolute terms, but it stands alone in Europe. No other European fusion company has achieved comparable backing.

The company's roadmap depends on Alpha succeeding. If the demonstration plant validates Proxima's stellarator design and achieves the fusion gain targets the company has set, Stellaris would move from concept to construction. That would represent a step change: the first privately developed commercial fusion power plant in operation anywhere. The capital secured now is positioned to keep that timeline on track through the early 2030s.