Commonwealth Fusion Systems
MIT-spinout pursuing commercial fusion power using high-temperature superconducting magnets
Energy
📍 Devens, MA
Founded 2018
Current Valuation
$5.0B
as of 2025-Q4
UNICORN
CFS is building SPARC, a compact tokamak using REBCO high-temperature superconducting magnets that achieved a world-record 20-Tesla field. Spun out of MIT's Plasma Science and Fusion Center. Plans to demonstrate net energy gain by 2027 and operate the ARC commercial plant in the early 2030s.
Company Profile
Last Round
Series B2 — $863M (Aug 2025) · Lead: Breakthrough Energy
IPO Status
no imminent plans
Founders & Key People
Bob MumgaardDennis WhyteBrandon SorbomMartin Greenwald
Investors
Breakthrough Energy Ventures · Bill Gates · Tiger Global · Coatue · Google · Khosla Ventures
Products
- SPARC (demonstration tokamak)
- ARC (commercial power plant)
Competitors
Helion Energy · TAE Technologies · Tokamak Energy · General Fusion
FusionEnergyMIT SpinoutGates Backed
Private-company numbers are not real-time. Reflects publicly disclosed valuations from press releases, news reports, and tender offers as of 2025-Q4. Refreshed quarterly.