MIT-spinout pursuing commercial fusion power using high-temperature superconducting magnets
Energy📍 Devens, MAFounded 2018
Current Valuation
$5.0B
as of 2025-Q4
UNICORN
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.
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.
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
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 ago
no imminent plansTotal raised $2.0B
Secondary Market
Implied price / share
$196.22
Open interest
17
Secondary price return by period
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
Round
Amount
Date
Lead Investor
Post-Money
Series B2
$863M
Aug 2025
Breakthrough Energy
—
Talent Signal
Hiring trend
▶ Hiring steady
22% of roles posted in last 30d
Open roles
63
via lever
Product-build share
56%
engineering, research, product, design
Trajectory
steady
product-led hiring — 56% of open roles build product; the rest are go-to-market and G&A.
Actively hiring with no tracked executive churn.
Open roles by month
Open roles by function
■ product-building ■ go-to-market / G&A
Assembly Process Engineer - ContractControl Software EngineerField Mechanical Engineer - AssemblyManager, Field Mechanical Engineering - AssemblyManufacturing Engineer - First ShiftManufacturing Engineer - Second Shift
Counted from Commonwealth Fusion Systems's live job board as of 2026-08-17; 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.