AN-030 Company lists · list
Fusion Companies: Private, Public, and the Timelines They Claim
Fusion companies in the HardwareMap index and on public markets: approach, HQ, disclosed raise, status, and each claimed timeline with date and source.
by the HardwareMap editors3 min read
From the HardwareMap index, REV 26.09, refreshed 3 Oct 2026
Contents
Fusion companies in the HardwareMap index number 4 as of REV 26.09: two in the United States and two in Germany, each betting on a different way to confine a fusing plasma. This page lists each with approach, HQ, disclosed raise and status, then records the timelines they claim, with dates and sources. It sits under the hardware startups index.
How we list fusion companies
A fusion company enters the index when it builds fusion hardware, publishes its approach and has a public funding record. Research labs and national programs are outside the index. We order the list by disclosed raise, and for each company we record one fact that can be checked: the machine it has built or is building now.
Private fusion companies in the index
Commonwealth Fusion Systems (Devens, Massachusetts) is an MIT spinout using high-temperature superconducting magnets to shrink the tokamak. It is building SPARC in Devens to demonstrate net fusion energy, with its first power plant, ARC, planned for Chesterfield County, Virginia.
Helion Energy (Everett, Washington) builds pulsed magneto-inertial fusion machines designed to recover electricity directly from the plasma, without steam turbines. Its Polaris prototype is operating, per its index record, and it began site work on its first plant, Orion, in Malaga, Washington, in July 2025 (Helion).
Proxima Fusion (Munich) designs power plants based on quasi-isodynamic stellarators, a twisted-coil design. Its index record shows a EUR 411 million round in July 2026, with RWE and Google among listed investors.
Marvel Fusion (Munich) pursues laser-driven fusion. It extended its Series B to EUR 113 million with EQT Ventures, Siemens Energy and the European Innovation Council Fund, and partners with Colorado State University on a laser facility.
Publicly traded fusion companies
Two fusion companies outside the index reached public markets by merger.
- General Fusion (Nasdaq: GFUZ) began trading on July 13, 2026, after completing its business combination with Spring Valley Acquisition Corp. III (General Fusion). It builds magnetized target fusion machines.
- TAE Technologies announced on December 18, 2025 an all-stock merger with Trump Media and Technology Group, with the combined company to trade under DJT. At announcement, the deal was expected to close in mid-2026 (TAE). The two companies filed the Form S-4 registration statement with the SEC on September 30, 2026, so the merger had not closed as of this REV (TAE).
Neither is in the index yet; both are candidates for the next REV.
Fusion timelines, as claimed
Every row below is a company claim, quoted with its date and source. None is an independent estimate.
How to read the table: a claim about a demonstration machine (SPARC, Alpha, LM26) is a physics milestone. A claim about a power plant (Orion, ARC) adds licensing, grid connection and a customer contract. The second kind has more ways to slip. We update each row when the company restates or moves a date.
What fusion companies have in common
- One core subsystem per approach. Superconducting magnets for the tokamak and stellarator, pulsed power for Helion, high-energy lasers for Marvel. That subsystem sets the cost and the schedule.
- Customers sign early. Helion's Microsoft agreement and CFS's Virginia plan both came before net energy was shown.
- Capital is concentrated. Commonwealth Fusion Systems alone holds more disclosed capital than the other three index companies together.
Fusion sits next to fission, storage and geothermal in climate tech startups, and within deep tech startups. Investors active in the category are in deep tech VC firms.
Continue with Nuclear Startups: SMRs, Microreactors, and Fuel.
Frequently asked questions
How many fusion companies are in the HardwareMap index?
The index lists four fusion companies as of REV 26.09: Commonwealth Fusion Systems and Helion Energy in the United States, and Marvel Fusion and Proxima Fusion in Germany. Each uses a different approach: a tokamak, pulsed magneto-inertial fusion, laser-driven fusion and a stellarator. Industry counts run higher because they include research programs and teams without hardware.
Are there publicly traded fusion companies?
Yes, as of October 2026. General Fusion began trading on Nasdaq under GFUZ on July 13, 2026, after a SPAC merger, according to the company. TAE Technologies announced in December 2025 an all-stock merger with Trump Media and Technology Group, with the combined company to trade as DJT. Neither is in the index yet. This is not investment advice.
When will fusion power reach the grid?
Nobody knows, and this page does not forecast it. Companies have made dated claims: Helion said in May 2023 that its first plant was expected online by 2028 to supply Microsoft, and Commonwealth Fusion Systems said in December 2024 that its ARC plant is expected to deliver power in the early 2030s. These are company targets, not independent estimates.
What is the difference between a tokamak and a stellarator?
Both confine hot plasma with magnetic fields in a ring. A tokamak drives a current through the plasma to help hold it, which is simpler to build but can cause instabilities. A stellarator uses twisted external coils so no plasma current is needed, which is steadier but harder to design and manufacture. Commonwealth Fusion builds tokamaks; Proxima Fusion builds stellarators.
Which fusion company has raised the most?
In the index, Commonwealth Fusion Systems has the largest disclosed raise at about $4 billion, followed by Helion Energy at about $1.5 billion, Proxima Fusion at about $664 million and Marvel Fusion at about $187 million. These are disclosed private rounds only. Raised capital measures investor conviction in a plan, not progress toward net energy.
HardwareMap records fusion companies and their claims without endorsing them. Open any company above for its datasheet, or browse the energy category.
The index
All 219 startups, filterable by category, hub, stage and funding.