Sam Altman, SoftBank invest in $425M round for Helion, a Seattle-area startup chasing fusion power

January 28, 2025

by Lisa Stiffler

Helion Energy announced a $425 million funding round that will help the Seattle-area fusion company chase the “Holy Grail” of clean energy.

The company’s new investors include SoftBank, Lightspeed Venture Partners and an unnamed university endowment. Sam Altman — OpenAI’s CEO and co-founder, as well as Helion’s longtime board chair and a past investor — also participated in the round with others.

Helion’s valuation topped $5.4 billion with the latest funding round. The company has raised more than $1 billion to date.

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