Commonwealth Fusion Systems (CFS), a company dedicated to advancing fusion energy, has successfully raised $863 million in a Series B2 funding round. This significant investment moves CFS closer to its ambition of becoming the first company worldwide to commercialize fusion energy, supporting the completion of its SPARC fusion demonstration machine and the development of its ARC power plant in Virginia.

This investment will help complete the SPARC fusion demonstration machine and advance the development of the ARC power plant in Virginia.

The oversubscribed funding round, announced on August 30, 2025, marks the largest capital raise among deep tech and energy companies since CFS’s $1.8 billion Series B round in 2021. With this latest investment, CFS has now secured nearly $3 billion, representing about one-third of the total capital invested in private fusion companies globally.

Bob Mumgaard, CEO and co-founder of CFS, stated: “Investors recognise that CFS is making fusion power a reality. They see that we are executing and delivering on our objectives. This funding recognises CFS’ leadership role in developing a new technology that promises to be a reliable source of clean, almost limitless energy – and will enable investors to have the opportunity to capitalise on the birth of a new global industry.”

The funding round attracted a diverse group of international investors, including banks, hedge funds, pension funds, private equity firms, sovereign wealth funds, and venture capitalists. New investors include Brevan Howard Macro Venture Fund, Counterpoint Global (Morgan Stanley), and Stanley Druckenmiller. A consortium of 12 Japanese companies, led by Mitsui & Co. and Mitsubishi, also participated, with notable contributors such as the Development Bank of Japan, Fujikura, JERA, and Kansai Electric Power. Existing investors, including Breakthrough Energy Ventures and Google, further increased their stakes.

Ally Yost, CFS’s senior vice-president of corporate development, remarked: “CFS offers investors the clearest path to bringing commercial fusion to the world – and an unprecedented opportunity to make a real impact as global demand for power accelerates with electrification and increased use of AI and data centres. Along with the promise of energy independence and security, fusion power will help to expand energy access, and with it, improve quality of life.”

The ARC power plant, set to be constructed in Chesterfield County, Virginia, aims to be the world’s first grid-scale fusion power plant. Developed in collaboration with Dominion Energy and Google, which will purchase half of the plant’s output, the project underscores CFS’s commitment to delivering clean, sustainable energy to meet growing global demands.