Fusion startups have raised $6B+. Here's who leads

Key Takeaways

• Commonwealth Fusion Systems has raised nearly $3 billion, about a third of all private fusion capital
• TAE Technologies announced a $6 billion merger with Trump Media in December 2025
• Helion promises electricity from fusion by 2028, with Microsoft as its first customer

Private fusion companies have collectively raised over $6 billion, and three startups now account for most of that capital. Commonwealth Fusion Systems leads with nearly $3 billion. TAE Technologies follows with $1.79 billion before its recent merger announcement. Helion rounds out the top tier with over $500 million and what may be the most aggressive commercialization timeline in the industry.

Fusion power spent decades as an engineering punchline. The joke wrote itself: commercial fusion is always ten years away. Three developments changed the calculus. Computer chips got faster. AI improved reactor simulations. High-temperature superconducting magnets matured enough to contain plasma at the temperatures required for fusion. In December 2022, Lawrence Livermore's National Ignition Facility crossed scientific breakeven, producing more energy from a fusion reaction than the lasers pumped in. That milestone proved the physics works. Now the question is whether startups can turn it into a business.

Who has raised the most for fusion?

Commonwealth Fusion Systems dominates. The Massachusetts company closed an $863 million Series B2 in August, bringing its total near $3 billion. That's roughly a third of all private investment in fusion. CFS is building Sparc, a tokamak reactor shaped like a doughnut. Superconducting tape wound around the reactor generates magnetic fields strong enough to compress plasma to fusion conditions. The heat converts water to steam, which spins turbines.

CEO Bob Mumgaard came from MIT, where he researched fusion reactors and high-temperature superconductors. CFS designed its magnets in collaboration with the university. The company expects Sparc to be operational in late 2026 or early 2027. After that, CFS plans to build Arc, a 400-megawatt commercial plant near Richmond, Virginia. Google has already agreed to buy half its output.

Breakthrough Energy Ventures, The Engine, and Bill Gates are among CFS's backers.

What's the TAE-Trump Media merger?

TAE Technologies took an unexpected turn in December 2025. The California fusion company announced an all-stock merger with Trump Media & Technology Group, valuing the combined entity at $6 billion. TAE receives $200 million upfront plus another $100 million when it files paperwork with the SEC.

TAE CEO Michl Binderbauer will serve as co-CEO alongside Devin Nunes, who had been running Trump Media solo. Before the merger, TAE had raised $1.79 billion from investors including Google, Chevron, and New Enterprise Associates. The company raised $150 million in June 2025 alone.

TAE's reactor design differs from CFS's tokamak. Founded in 1998 as a spinout from UC Irvine, TAE uses a field-reversed configuration. Two plasma shots collide in the center of the reactor. Particle beams then bombard the plasma, keeping it spinning in a cigar shape. That stabilizes the plasma long enough for fusion to occur and heat to be extracted.

When will Helion deliver power to Microsoft?

Helion has set the most aggressive deadline: electricity from its reactor by 2028. Microsoft signed on as the first customer.

The Everett, Washington company also uses a field-reversed configuration, but with a different geometry. Its reactor resembles an hourglass with a bulge where the two halves meet. At each end, magnets spin plasma into doughnut shapes that hurtle toward each other at over 1 million miles per hour. When they collide, additional magnets induce fusion.

Here's where Helion diverges from the pack. Most fusion concepts generate heat to boil water and spin turbines, the same cycle used in coal and fission plants. Helion harvests electricity directly. When fusion occurs, it amplifies the plasma's own magnetic field, inducing current in the reactor's magnetic coils. That current becomes the output.

How many fusion startups exist?

The Fusion Industry Association counted 43 private fusion companies globally in its 2023 survey. A decade ago, that number was in the single digits. Total private investment has passed $6.2 billion, with the pace accelerating after the 2022 breakeven result.

Not all of these companies pursue the same physics. Tokamaks like CFS's Sparc represent one approach. Field-reversed configurations like TAE and Helion represent another. Other startups experiment with stellarators, inertial confinement, and more exotic designs. The diversity reflects uncertainty about which path will prove cheapest to build and operate at scale.

What's the difference between scientific and commercial breakeven?

Scientific breakeven, achieved in December 2022, means the fusion reaction itself produced more energy than the lasers delivered to the fuel pellet. Commercial breakeven is harder. It means the reactor produces more energy than the entire facility consumes, including the lasers, magnets, cooling systems, and control electronics. No one has reached commercial breakeven yet.

The gap matters for investors. Scientific breakeven proves the physics. Commercial breakeven proves the business model. Startups are betting they can close that gap faster than government labs, which have historically moved at a slower pace.

Frequently Asked Questions

Which fusion startup has raised the most money?

Commonwealth Fusion Systems leads with nearly $3 billion, representing about a third of all private capital invested in fusion.

Who is Helion's first customer?

Microsoft has agreed to purchase electricity from Helion's reactor, which the company says will produce power by 2028.

What is the TAE-Trump Media deal worth?

The all-stock merger values the combined company at $6 billion. TAE receives $200 million upfront and $100 million upon SEC filing.

Has any fusion reactor achieved commercial breakeven?

No. Scientific breakeven was achieved in December 2022, but commercial breakeven, where the entire facility produces net energy, remains unproven.

How many private fusion companies exist?

The Fusion Industry Association counted 43 globally in 2023, up from a handful a decade ago.

Source: Startups | TechCrunch / Tim De Chant