Helion, the fusion startup backed by Sam Altman, announced on Thursday that it had raised $465 million in a new funding round that values the company at $15.5 billion. The cash infusion lands as Helion is racing 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.
Funding Round Details
The new round, a Series G, was led by Thrive Capital with a long list of participants, including new investors Alta Park Capital, Anti Fund, BoxGroup, Lux Capital, Peak XV Partners, and Bill Ford, along with existing investors, which 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. Altogether, Helion said it has raised $1.5 billion to date. The startup last raised $425 million in January 2025.
Helion's Unique Fusion Technology
Helion’s approach to fusion power differs from many of its peers. Some use magnets to contain the superheated plasma required for fusion conditions, while others use lasers to compress fusion fuel until it reacts. In both cases, the majority of startups plan to use steam turbines to transform the intense heat into electricity. But Helion, which uses magnets to compress the fuel, intends to harvest electricity straight from the magnets themselves. When fusion occurs in the plasma inside the reactor, it expands, pushing against the magnetic fields. That force can be drawn off the magnets as electricity, similar to how an electric vehicle can reverse its motors to provide braking force and recharge the battery. Such a configuration would dramatically improve the efficiency of a fusion power plant. But some fusion experts are skeptical it could work. That’s in part because Helion, unlike many of its competitors, doesn’t frequently publish in peer-reviewed journals, so physicists haven’t been able to poke at the theoretical underpinnings. David Kirtley, Helion’s CEO, argues that eventual results from the company’s fusion devices should be sufficient. “We don’t want to theorize about fusion,” he told TechCrunch last year. “We just want to go build it.”
Fusion Sector Investment Surge
Helion isn’t alone in attracting fresh funding. The fusion sector has become an investor darling in recent months. Below is a summary of recent funding rounds by other fusion startups mentioned in the announcement:
| Company | Announced | Amount |
|---|---|---|
| Focused Energy | Last week | $240 million |
| Thea Energy | Last week | $100 million |
| Inertia Energy | February | $450 million (Series A) |
| Type One Energy | January | $250 million (Series B) |
Potential for AI and Energy Markets
The investments have poured in despite fusion’s lengthy timeline. Though several companies have made progress in recent months on milestones they say pave the way to a viable power plant, most predict they won’t begin operating their first commercial-scale power plant until the middle of the next decade at the earliest. Part of the appeal is fusion’s potential to deliver nearly limitless amounts of always-on energy using little more than seawater. For AI-focused tech companies, that’s an attractive proposition. But it also has the potential to disrupt other trillion-dollar energy markets if fusion power companies can aggressively drive costs down. The timelines might be a bit longer than VCs are used to, but the potential payoff could be a lot bigger.
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