Fusion Startup Helion Nearly Triples Valuation to $15.5 Billion in Thrive-led Round

Helion Energy, a nuclear fusion startup backed by OpenAI’s Sam Altman, still has to prove it can produce electricity to serve data centers and other customers. But investors seem confident it can deliver.

The Everett, Wash.–based company said it has raised $465 million in a funding round led by Thrive Capital, the investment firm founded by Josh Kushner, a big backer of OpenAI. Helion’s valuation after the investment was $15.5 billion, nearly triple the company’s $5.43 billion valuation during its prior round, announced in January 2025.

Other investors in the round include Alta Park Capital, Anti Fund, BoxGroup, Lux Capital, Peak XV Partners and Bill Ford, the executive chair of the Ford Motor Co. Many of the company’s existing investors, including Lightspeed Venture Partners, SoftBank Vision Fund 2 and Mithril Capital, also participated.