The Fusion Startup Billionaires: Who Has $100M+ and What Are They Building?

Fusion energy is no longer just a physics experiment confined to national laboratories. As of June 2026, a handful of well-funded firms have secured over $100M in capital, moving from theoretical models to pilot reactors. Whether it’s Commonwealth Fusion Systems or Helion Energy, these companies are burning cash at record rates to achieve net energy gain. This isn’t just venture capital hype; it is a race to provide baseload power that could eventually replace the fossil fuel grid you rely on today.

Commonwealth Fusion Systems: The Tokamak Heavyweight

Commonwealth Fusion Systems (CFS) remains the biggest player in the room, having raised north of $2 billion. Their SPARC reactor is the closest thing we have to a commercial prototype. By using high-temperature superconducting (HTS) magnets, they can shrink the tokamak design, making it significantly cheaper to build than the massive ITER project. When I look at their 2026 progress reports, the magnetic field strength is the real differentiator here. They are pushing 20 tesla, which is a massive leap over legacy designs. While they haven’t achieved sustained grid-scale fusion yet, their recent plasma containment tests suggest they are on track for their 2027 goal of net energy. If you want to bet on a winner, this is the one with the most institutional support.

Why HTS magnets change the math

Standard copper magnets require massive cooling systems and consume incredible amounts of power. CFS uses Rare-Earth Barium Copper Oxide (REBCO) tapes. These HTS magnets work at higher temperatures, meaning smaller reactors, less cooling infrastructure, and ultimately a lower capital expenditure per megawatt compared to the multi-billion dollar reactors of the past.

Helion Energy: Going for Pulsed Non-Ignition

Helion Energy has taken a different path, focusing on pulsed magnetic fusion. They aren’t trying to build a traditional tokamak. Instead, they fire plasma rings into a reaction chamber where magnetic fields compress them to fusion conditions. They’ve raised over $500M and have a very public partnership with Microsoft to deliver power by 2028. Their Polaris prototype is currently undergoing testing to prove they can recover electricity directly from the fusion process without a steam turbine. If they pull this off, the energy efficiency gains would be staggering. I’m skeptical about their timeline, but the direct-to-electricity conversion is a genius move if the physics holds up under sustained load.

Direct energy recovery explained

Most power plants use heat to boil water, spin a turbine, and generate electricity. Helion skips the steam cycle. They use the expansion of the plasma against a magnetic field to induce current directly in the coils. This theoretically reduces energy waste by 30% or more compared to thermal conversion.

Zap Energy: The Z-Pinch Contender

Zap Energy is the budget-friendly underdog of the fusion world. Having raised around $200M, they focus on a sheared-flow stabilized Z-pinch. It’s elegant because it doesn’t require the massive superconducting magnets that make CFS or ITER reactors so expensive. They basically use plasma current to create the magnetic fields needed to hold the fusion reaction together. Their FuZE-Q device has shown consistent results in recent months, demonstrating that you can achieve fusion conditions in a device that fits in a decent-sized garage. It’s not producing gigawatts yet, but the scalability of a Z-pinch reactor is much better than a multi-story tokamak.

The simplicity factor

Complexity is the enemy of reliability. By removing the need for external magnets and cryogenics, Zap Energy targets a much smaller footprint. This could eventually allow for modular power plants that are deployed to factories or data centers rather than massive, centralized utility hubs.

Tokamak Energy: The British Standard

Based in the UK, Tokamak Energy has secured over $250M to pursue spherical tokamaks. Like CFS, they are heavily invested in HTS magnets, but their focus is on the compact spherical shape. The ST40 reactor has already hit 100 million degrees Celsius, which is the benchmark for fusion. They are currently scaling up to their ST80-HTS design. Their business model is quite transparent: sell the magnet technology and the reactor IP to energy companies. They aren’t trying to be the utility company themselves, which I think is a smarter play for a tech firm. They are effectively the ‘Intel’ of the fusion hardware world.

Spherical vs. Conventional

A spherical tokamak is more efficient at confining plasma than the donut-shaped ones we’ve seen for decades. It allows for higher pressure in a smaller volume, which is exactly what you need to keep the fusion reaction stable without the massive size requirements of traditional designs.

⭐ Pro Tips

• Check the ARPA-E fusion project database to see which startups are getting government grants alongside their private funding.
• Don’t buy into the ‘fusion is 10 years away’ marketing; look for peer-reviewed papers on plasma confinement time, not just press releases.
• Follow the magnet supply chain; companies like CFS are driving up demand for REBCO tapes, which is a great indicator of real-world construction progress.

Frequently Asked Questions

Final Thoughts

The fusion landscape is shifting from ‘can we do it?’ to ‘how do we build it at scale?’. With over $3 billion combined in the sector, we are seeing real hardware hit the floor. If you’re invested in energy stocks, keep a close eye on these private firms. I’ll be tracking their milestone announcements throughout the rest of 2026. Stay updated by bookmarking this page or subscribing to my weekly tech newsletter.