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Commonwealth Fusion Systems

MIT-spinout pursuing commercial fusion power using high-temperature superconducting magnets
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.
Energy 📍 Devens, MA Founded 2018
Current Valuation
$5.0B
as of 2025-Q4
UNICORN

QL Price

$5.0B
0% vs last round
QuantLogix's current estimate for Commonwealth Fusion Systems, published 2026-10-07 — in line with the last disclosed round of $5.0B (2025-Q4).
Confidence
medium
Basis
secondary led
What backs this price
Last disclosed round $5.0B 2025-Q4 weight 0.59
Secondary market print $5.0B 2026-06-27 weight 0.54
How this price has held up
No round has priced for Commonwealth Fusion Systems since QuantLogix began publishing a price for it, so there is nothing to grade yet. The claim above is on the record from 2026-10-07 and will be graded against the next priced round. See the full accuracy record →
How to actually get exposure to Commonwealth Fusion Systems →
Which publicly-traded funds already hold it, what $10,000 buys, and whether any route is open to you.
Cite this price as QuantLogix QL Price, Commonwealth Fusion Systems, 2026-10-07 (30fb2b2572cb2b42). The id pins this exact claim, so a citation stays checkable after the price moves. Model estimate for research — not a quote, target price, or investment advice.

IPO Outlookprivate

Is Commonwealth Fusion Systems going public?
No. Commonwealth Fusion Systems has no imminent IPO plans on record. It is still private.
What is Commonwealth Fusion Systems' valuation in 2026?
Commonwealth Fusion Systems is valued at $5.0B as of 2025-Q4, set by its Series B2 ($863M, Aug 2025). That is the last confirmed mark, not a live price — private shares do not trade continuously.
Has Commonwealth Fusion Systems filed an S-1?
No public S-1 is on file for Commonwealth Fusion Systems.
Who are Commonwealth Fusion Systems' investors?
Commonwealth Fusion Systems' investors include Breakthrough Energy Ventures, Bill Gates, Tiger Global, Coatue, Google, Khosla Ventures.
How much has Commonwealth Fusion Systems raised?
Commonwealth Fusion Systems has raised $2.0B in total, most recently a Series B2 of $863M in Aug 2025.
Is Commonwealth Fusion Systems publicly traded — can you buy Commonwealth Fusion Systems stock?
No. Commonwealth Fusion Systems is a private company — its shares are not listed on any exchange and there is no ticker. The routes to exposure are pre-IPO secondary marketplaces and funds (accredited investors), employee tender offers when the company runs one, and public companies with read-through exposure. QuantLogix maps every route it can verify for Commonwealth Fusion Systems on its Pre-IPO Access Desk.
How to actually get exposure to Commonwealth Fusion Systems →
Answers are derived from the roster record shown on this page — filing status, last round and confirmed marks. Where the record is silent, the answer says so rather than guessing.

Company Profile

CEO
Bob Mumgaard
Founded
2018
HQ
Devens, MA
Employees
~700
Total Raised
$2.0B
Last Round
Series B2 — $863M (Aug 2025) · Lead: Breakthrough Energy
IPO Status
no imminent plans

Fundraising Status

Series B2 · $863M · 1y 2mo ago
no imminent plansTotal raised $2.0B

Secondary Market

Implied price / share
$196.22
Open interest
17
Secondary price return by period
Secondary market period returns3-month-14.8%6-month-9.4%1-year+42.3%All-time+63.5%
Implied per-share price from private secondary transactions, as of Jun 2026. This is a point estimate, not a quote — the feed carries no bid, ask or spread, and a secondary print is evidence of what someone paid on that date rather than a live market. Compare across every tracked name →

Latest Funding Round

RoundAmountDateLead InvestorPost-Money
Series B2$863MAug 2025Breakthrough Energy—

Talent Signal

Hiring trend
▲ Hiring uptrend
+59% vs 2026-08
Open roles
100
via lever
Product-build share
54%
engineering, research, product, design
Trajectory
expanding
product-led hiring — 54% of open roles build product; the rest are go-to-market and G&A.
No tracked executive churn; open roles trending up.
Open roles by month
Open roles by month63Aug '26100Sep '26
Open roles by function
Open roles by functionOther33Hardware26Engineering25Ops & People10Finance & Strategy3Research2Security1
■ product-building   ■ go-to-market / G&A
Assembly Process Engineer - ContractAssembly Test Implementation EngineerControl Software EngineerDirector, Manufacturing, Operations & Supply Chain FinanceElectrical EngineerFiber Optics Manufacturing Engineer
Counted from Commonwealth Fusion Systems's live job board as of 2026-09-15; role functions classified from posting titles. Open-role counts are an activity signal, not headcount. Refreshed monthly.

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.