Commonwealth Fusion Systems

Summary active Updated Jul 31, 2026

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Location Devens, MA
Founded 2018
Latest Stage Growth
Total Raised $4B

Investors

Mike Schroepfer Series B2 ($863M) — participant (2025)
Carmichael Roberts Series B ($1.8B) (2021)
Stanley Druckenmiller 2025-08-28 (2025)
Maryanna Saenko Series A (2019)
Steve Jurvetson Early (2019)
Craig Shapiro Early Stage (2018)
Marc Benioff Venture (2021)
Khosla Ventures prior (2021)
Gigascale Capital Series B2 ($863M) — participant (2025)
duquesne-family-office 2025-08-28 (2025)
Future Ventures Series A (2019)
Collaborative Fund Early Stage (2018)
TIME Ventures Venture (2021)

Founders

Bob Mumgaard Co-Founder & CEO

About

Commonwealth Fusion Systems (CFS) is a Massachusetts-based fusion energy company spun out of MIT that is developing magnetic-confinement tokamak reactors using high-temperature superconducting magnets 12. The company is building Sparc, a demonstration reactor targeting scientific breakeven in 2027, and Arc, its first commercial power plant planned for Virginia 12. Major offtake commitments include a 200-megawatt power purchase agreement with Google and a $1 billion+ commitment with Eni 12. On 2026-07-30 CFS announced $1B in new financing from pension funds, sovereign wealth funds, and infrastructure and industrial corporate partners, bringing its total funding to approximately $4B — making it the best-funded fusion startup in the world 12.

Disclaimer: This is a lean profile built from initial round coverage and may be expanded as more information becomes available.

Funding History

Date Round Amount Lead Co-investors
2026-07-30 Growth $1B Not disclosed Pension funds, sovereign wealth funds, infrastructure and industrial corporate partners 12

Prior notable investors include Nvidia, Google, Khosla Ventures, and Breakthrough Energy Ventures 12.

What Investors Say

No independently sourced investor commentary beyond press-release attribution at this time.

What Founders Say

No independently sourced founder quotes available at this time.

Sources


  1. TechCrunch, “Fusion power darling Commonwealth Fusion Systems raises another $1B,” July 30, 2026. Accessed July 2026. https://techcrunch.com/2026/07/30/fusion-power-darling-commonwealth-fusion-systems-raises-another-1b/

  2. Commonwealth Fusion Systems, “Commonwealth Fusion Systems Raises Another $1 Billion, Bringing Total Capital Raised to $4 Billion,” July 30, 2026. Accessed July 31, 2026. https://cfs.energy/news-and-media/commonwealth-fusion-systems-raises-another-1-billion-bringing-total-capital-raised-to-4-billion/