The oversubscribed and upsized round had participation from new investors, including Lightspeed Venture Partners, SoftBank Vision Fund 2, and a major university endowment, and existing investors including Sam Altman, Mithril Capital, Capricorn Investment Group, Dustin Moskovitz through Good Ventures Foundation, and Nucor. This latest round of funding will bring the total invested in Helion to over $1 billion and values the company at $5.425 billion post-money.

Helion is a fusion energy company focused on generating zero-carbon electricity from fusion. Its mission is to build the world's first fusion power plant, enabling a future with unlimited clean electricity.