Helion

Helion has raised $977 million, including a major $425M Series F in January 2025, earlier funding in Series A (2014), and a significant Series E round in 2021 totaling $0.5B plus $1.7B in commitments. Founded in 2010, the company develops magnetic nuclear fusion reactors using deuterium and pulsed magnetic confinement. Backed by Y Combinator, Mithril, Sam Altman, and Capricorn Investment Group, Helion continues to push toward commercial fusion energy and scale breakthrough clean-energy production for industrial applications.