Helion Energy on Thursday announced a $465 million Series G investment round that values the Everett, Washington fusion startup at $15.5 billion post-money — nearly triple its prior mark and a fresh signal that private fusion is shifting from a long-shot science bet to an emerging infrastructure category. The round brings total capital raised to roughly $1.5 billion as Helion races to deliver electricity from its first commercial plant to Microsoft as early as 2028.
Thrive leads, Lux and Lightspeed double down
Thrive Capital led the financing, joined by new investors Alta Park Capital, Anti Fund, BoxGroup, Lux Capital, Peak XV Partners and Bill Ford, the Ford Motor Company executive chairman. Existing backers Capricorn Technology Impact Funds, Lightspeed Venture Partners, Mithril Capital, SoftBank Vision Fund 2 and Dustin Moskovitz through the Good Ventures Foundation also re-upped. "Helion has the technical ambition, pace of execution and commercial orientation to define a new category of energy," said Vince Hankes, partner at Thrive Capital, in the announcement.
Polaris milestones drive the raise
The Series G arrives weeks after Helion's seventh-generation Polaris prototype became the first privately funded fusion machine to operate with deuterium-tritium fuel and set a company record by exceeding 150 million degrees Celsius in plasma temperature. Construction is underway on Orion, Helion's first fusion power plant, on a site in Malaga, Washington that was permitted earlier this year by the Chelan County Hearing Examiner.
Why now: AI factories are reshaping the power buyer
Helion CEO David Kirtley framed the financing as accelerating delivery against a tightening grid, with hyperscaler load growth pulling forward demand for always-on clean power. The company's 2023 power purchase agreement with Microsoft for at least 50 MW of fusion electricity remains the most aggressive timeline in the sector. Investors are now treating fusion as adjacent to the AI infrastructure thesis that has lifted neighbors like defense AI and sovereign AI compute, and pacing alongside small modular reactor deals such as X-energy's UK Xe-100 submission and NuScale's RoPower decision.
Reporting based on coverage from Helion Energy, Thrive Capital, TechCrunch and BusinessWire.