The firm's latest Series F round brings the total investment into Helion over the $1 billion line, and it's aiming to begin delivering power from a single fusion 50-MW plant to Microsoft by 2028.

Few fusion startups have been as closely watched as Helion. The 12-year-old company is backed by Sam Altman, rumored to be in talks with OpenAI, and has a deal to supply Microsoft with electricity ...

Fresh off a $425 million Series F funding round, Helion is now valued at $5.4 billion, the startup announced today (Jan. 28). The company’s co-founder and CEO David Kirtley said the massive ...

Polaris, Helion’s seventh prototype, sits inside a 27,000-square-foot building in Everett, Washington. It took more than three years to build, which is quick by fusion industry standards.