Helion raises $465M Series G at a $15.5B valuation to build its first fusion power plant
What's the deal? Helion Energy, the nuclear fusion startup backed by OpenAI co-founder Sam Altman, has closed a $465 million Series G led by Thrive Capital, valuing the company at $15.5 billion. New backers include Alta Park Capital, Anti Fund, BoxGroup, Lux Capital, Peak XV Partners and Bill Ford, alongside existing investors Capricorn, Lightspeed Venture Partners, Mithril, SoftBank Vision Fund 2 and Dustin Moskovitz's Good Ventures. Helion says it has now raised $1.5 billion in total.
Why now? The capital lands as Helion races to complete Orion, its first power plant, with an aggressive target to deliver fusion power to the grid as early as 2028 under its deal with Microsoft. Investor appetite for fusion has surged as AI's electricity demands climb.
What could go wrong? No company has yet produced net energy from a commercial fusion reactor, and timelines across the sector have slipped repeatedly. Helion's magnet-based approach, which harvests electricity directly from the magnets rather than via steam turbines, draws skepticism from some fusion experts given the company rarely publishes in peer-reviewed journals.
The signal: Helion's valuation leap shows how fast capital is flowing into deep-tech bets that sit upstream of the AI boom, with fusion emerging as one of the clearest plays on the energy needed to power it.
Read more: TechCrunch
