Helion, the fusion startup backed by Sam Altman, announced on Thursday that it raised $465 million in a new funding round valuing the company at $15.5 billion. The cash infusion lands as Helion races to complete Orion, its first power plant. The startup has set an aggressive timeline to deploy fusion power to the grid as early as 2028 if it can deliver on the terms of its deal with Microsoft. Helion last raised $425 million in January 2025. Altogether, Helion said it has raised $1.5 billion.
Series G Led By Thrive Capital With New And Existing Investors
The new round, a Series G, was led by Thrive Capital. New investors include Alta Park Capital, Anti Fund, BoxGroup, Lux Capital, Peak XV Partners, and Bill Ford. Existing investors include Capricorn Technology Impact Funds, Lightspeed Venture Partners, Mithril Capital, Dustin Moskovitz through Good Ventures Foundation, SoftBank Vision Fund 2, and a university endowment fund.
Helion Harvests Electricity Directly From Magnets, Differing From Peers
Helion’s approach to fusion power differs from many peers. Some startups use magnets to contain superheated plasma required for fusion conditions. Others use lasers to compress fusion fuel until it reacts. In both cases, most startups plan to use steam turbines to transform intense heat into electricity. Helion uses magnets to compress the fuel but intends to harvest electricity straight from the magnets themselves. When fusion occurs in the plasma inside the reactor, it expands, pushing against magnetic fields. That force can be drawn off the magnets as electricity, similar to how an electric vehicle reverses its motors to provide braking force and recharge a battery.
Such a configuration would dramatically improve the efficiency of a fusion power plant. But some fusion experts are skeptical it could work, in part because Helion does not frequently publish in peer-reviewed journals. Physicists have not been able to examine the theoretical underpinnings. David Kirtley, Helion’s CEO, argued that eventual results from the company’s fusion devices should be sufficient. “We don’t want to theorize about fusion. We just want to go build it,” he said.
Fusion Sector Attracts Fresh Funding Despite Lengthy Timelines
Helion is not alone in attracting fresh funding. The fusion sector has become an investor darling in recent months. Focused Energy and Thea Energy both announced new rounds last week: Focused for $240 million, Thea for $100 million. In February, Inertia Energy emerged from stealth with a $450 million Series A. The month before, Type One Energy said it was raising $250 million for a Series B.
Investments have poured in despite fusion’s lengthy timeline. Several companies have made progress on milestones they say pave the way to a viable power plant. Most predict they will not begin operating their first commercial-scale power plant until the middle of the next decade at the earliest. Fusion’s potential to deliver nearly limitless amounts of always-on energy using little more than seawater appeals to AI-focused tech companies. It also has the potential to disrupt other trillion-dollar energy markets if fusion power companies can aggressively drive costs down. Timelines may be longer than VCs are used to, but the potential payoff could be larger.
Featured image credits: wickelbock9 – pixabay.com
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