Commonwealth Fusion Systems

Commonwealth Fusion Systems (CFS) is a privately held fusion energy company spun out of MIT's Plasma Science and Fusion Center in 2018 to commercialize high-temperature superconducting magnet technology for fusion power. The company is building SPARC, a demonstration tokamak at its Devens, Massachusetts campus intended to demonstrate net fusion energy gain, and ARC, a planned grid-scale commercial fusion power plant in Chesterfield County, Virginia, targeting operation in the early 2030s. CFS has raised roughly $4 billion in disclosed private funding since 2018 across seed, Series A, A2, B and B2 rounds plus a further 2026 growth round, from investors including Eni, Google, Tiger Global Management, Temasek, Breakthrough Energy Ventures and Khosla Ventures, and has signed power purchase agreements with Eni (more than $1 billion) and Google (roughly 200 MW). In July 2026 CFS hired former Moderna CFO Lorence Kim, and subsequent press coverage pointed to a possible public listing within two to three years, though the company remains private with no S-1 filed as of September 2026.