Startup · United States
Commonwealth Fusion Systems
HQ Devens, MassachusettsFounded 2018501-1000 employeesUpdated
Develops tokamak fusion machines and commercial fusion power plants.
Funding8 rounds · $3.86B
- Equity raised
- $3.86B
- Debt, secondaries & grants
- $15.0M
- Latest
- $1.00BStage undisclosed · Jul 30, 2026
| Announced | Stage | Amount | Valuation | Lead investors | Other investors | Confidence |
|---|---|---|---|---|---|---|
| Jul 30, 2026 | Undisclosed | $1.00B | — | — | — | Confirmed |
| Aug 27, 2025 | Series B | $863M | — | — | — | Reported |
| Jun 30, 2025 | Strategic | Undisclosed | — | — | — | Reported |
| Jun 6, 2024 | Grant | $15.0M | — | — | — | Reported |
| May 31, 2023 | Grant | Undisclosed | — | — | — | Reported |
| Dec 1, 2021 | Series B | $1.80B | — | Tiger Global Management | — | Reported |
| May 26, 2020 | Series A | $84.0M | — | Temasek | — | Reported |
| Jun 27, 2019 | Series A | $115M | — | Breakthrough Energy Ventures | — | Reported |
- UndisclosedConfirmed$1.00BJul 30, 2026
- Series B$863MAug 27, 2025
- StrategicUndisclosedJun 30, 2025
- Grant$15.0MJun 6, 2024
- GrantUndisclosedMay 31, 2023
- Series BLed by Tiger Global Management$1.80BDec 1, 2021
- Series ALed by Temasek$84.0MMay 26, 2020
- Series ALed by Breakthrough Energy Ventures$115MJun 27, 2019
Raised counts equity rounds; debt, secondary sales and grants are totaled separately. Amounts in other currencies are converted at the announcement month's average rate. A ~ marks an estimated or converted amount.
Capabilities1
| Technology | Role | Maturity | TRL | Notes | Confidence |
|---|---|---|---|---|---|
| Nuclear energy and propulsion | Developer | — | — | classify_sectors run 37, haiku, taxonomy 2026-10-18b: Develops tokamak fusion machines and commercial fusion power plants; no defense use is stated. | Reported |
- Developerclassify_sectors run 37, haiku, taxonomy 2026-10-18b: Develops tokamak fusion machines and commercial fusion power plants; no defense use is stated.—Reported
Maturity and TRL describe this organization's work; the field-wide maturity is on each technology's page.
People6
| Person | Role |
|---|---|
| Bob Mumgaard | Co-founder |
| Dan Brunner | Co-Founder and Chief Technology Officer |
| Martin Greenwald | Co-founder |
| Robert Mumgaard | Chief Executive Officer and Co-Founder |
| Brandon Sorbom | Chief Scientific Officer |
| Joe Paluska | Chief Marketing Officer |
Sources6
Profile3
- 1
Supports Organization · linkedin url
“https://www.linkedin.com/company/11076301/”
- 2
Supports Organization · founded year
“In 2018, CFS was spun out of MIT”
- 3
LinkedIn · Supports Organization · ownership
“Type Privately Held”
Funding2
- 4
Supports Funding round, Organization
“today announced that it raised $1 billion of additional equity financing.”
- 5
Octen Business Search · Supports Funding round, Organization · employee range, Role
“funding round: Series A, 2020-05-26, USD 84,000,000, lead: Temasek”
People1
- 6
Supports Organization · hq city, Organization · hq region, Role
“at its headquarters in Devens, Massachusetts”
Each fact on this page is attached to the sources that support it. Archived copies are linked when we keep one.