Every Fusion Startup That Has Raised Over $100 Million

Fusion energy is moving from a long-term scientific ambition toward a potentially transformative source of clean power. For decades, commercial fusion was often described as being “a decade away.” Today, major advances in computing, artificial intelligence, superconducting magnets, laser technology, and plasma science are helping bring fusion technology closer to reality.

At the same time, investors are putting billions of dollars into private fusion companies. Startups are exploring different approaches, including tokamaks, stellarators, inertial confinement, field-reversed configurations, and magnetized target fusion.

Below is a look at the fusion startups that have raised more than $100 million in private capital, based on the funding information provided by FusionX and other cited industry data.

Why Fusion Energy Is Attracting Investors

Fusion attempts to recreate the nuclear reaction that powers the sun. Unlike conventional nuclear fission, fusion combines light atomic nuclei to release energy.

The technology could potentially provide large amounts of electricity with low carbon emissions and abundant fuel sources. However, creating a commercially viable fusion power plant remains a major engineering challenge.

Three developments have helped accelerate progress:

• More powerful computer chips for complex simulations
• AI-powered systems for reactor design and plasma control
• High-temperature superconducting magnets for stronger magnetic confinement

Another major milestone came in December 2022, when researchers at the U.S. National Ignition Facility achieved a fusion reaction that produced more energy from the fuel than the laser energy delivered to it. This was an important scientific breakthrough, although commercial fusion still requires significantly more energy and engineering efficiency.

1. Commonwealth Fusion Systems

Commonwealth Fusion Systems (CFS) is one of the world’s most heavily funded fusion startups. According to FusionX, the company has raised approximately $3.94 billion in committed capital.

CFS uses a tokamak reactor design, a doughnut-shaped system that uses powerful magnetic fields to confine extremely hot plasma.

Its flagship project, SPARC, is being developed in Massachusetts. The company aims to demonstrate scientific breakeven and produce commercially relevant fusion energy.

CFS is also planning ARC, a commercial fusion power plant expected to generate approximately 400 megawatts of electricity. Google has agreed to purchase half of ARC’s planned output.

Major investors include Breakthrough Energy Ventures, The Engine, Bill Gates, and other institutional and strategic investors.

2. Helion

Helion has raised approximately $3.2 billion in committed capital, according to FusionX.

The Washington-based company is pursuing an ambitious goal: generating commercial electricity from fusion by 2028.

Helion uses a field-reversed configuration. Its reactor accelerates and collides plasma at extremely high speeds. The resulting fusion reaction produces changes in the magnetic field that can generate electricity directly.

Microsoft has signed an agreement to purchase electricity from Helion’s planned fusion power plant.

The company raised $465 million in its Series G, bringing its valuation to approximately $15.5 billion. Its investors include Sam Altman, SoftBank Vision Fund 2, Reid Hoffman, KKR, BlackRock, Mithril Capital Management, and Capricorn Investment Group.

3. TAE Technologies

Founded in 1998, TAE Technologies is one of the longest-running private fusion companies.

The company has raised approximately $1.65 billion before its proposed transaction with Trump Media & Technology Group.

TAE uses a field-reversed configuration combined with particle beams to help stabilize plasma and extend the conditions needed for fusion.

Its investors have included Google, Chevron, and New Enterprise Associates.

In December 2025, TAE announced plans to merge with Trump Media & Technology Group in an all-stock transaction valued at approximately $6 billion.

4. Pacific Fusion

Pacific Fusion attracted significant attention after announcing a Series A of more than $1 billion.

The company is developing an inertial confinement fusion system, but instead of relying on traditional lasers, it plans to use synchronized electromagnetic pulses.

Its approach requires hundreds of powerful generators to produce extremely short and precisely timed energy pulses. These pulses must converge on a fusion target simultaneously.

The company is led by CEO Eric Lander, who previously played a major role in the Human Genome Project.

Pacific Fusion’s investors are expected to provide funding in stages as the company reaches specific technical milestones.

5. Proxima Fusion

Germany-based Proxima Fusion is developing a stellarator-based fusion system and has raised more than $682.9 million, according to FusionX.

Stellarators use complex magnetic fields to confine plasma inside a ring-shaped reactor. Unlike traditional tokamaks, stellarators are designed to maintain plasma stability without relying on a large plasma current.

Proxima plans to develop Alpha, its net-energy demonstrator, in the early 2030s. Its longer-term goal is Stellaris, a commercial fusion power plant.

Investors include Google, RWE, Balderton Capital, Cherry Ventures, East X Ventures, and XTX Ventures.

6. Shine Technologies

Shine Technologies has raised approximately $1 billion.

Unlike startups focused exclusively on producing electricity from fusion, Shine is taking a broader commercial approach.

The company is developing businesses around neutron production, medical isotopes, nuclear waste recycling, and related technologies while continuing to develop capabilities that could support future fusion power.

Shine’s most recent funding included a $240 million round led by NantWorks, with participation from several institutional investors.

7. Inertia Enterprises

Inertia Enterprises emerged from stealth with $450 million in Series A funding.

The startup is focused on inertial confinement fusion, using high-powered lasers to compress fusion fuel pellets.

Its founding team includes Annie Kritcher, who worked on the National Ignition Facility’s successful fusion experiments, along with Stanford professor Mike Dunne and entrepreneur Jeff Lawson.

The company has also signed agreements aimed at commercializing technology developed at the National Ignition Facility.

8. General Fusion

Canadian company General Fusion has raised more than $442 million, according to FusionX.

The company is developing a technology known as magnetized target fusion.

Its reactor surrounds plasma with a liquid metal wall. Mechanical pistons compress the liquid metal, which in turn compresses the plasma and creates the conditions required for fusion.

General Fusion has faced funding challenges while developing its LM26 reactor. However, additional financing helped the company continue its development.

In 2026, the company went public through a reverse merger with a special purpose acquisition company, with the transaction generating approximately $127 million for the business.

9. Zap Energy

Zap Energy has raised approximately $325 million.

Rather than relying on expensive superconducting magnets or massive lasers, Zap uses electrical current to generate a magnetic field that confines and compresses plasma.

The company has also expanded its strategy beyond fusion. It announced plans to explore nuclear fission and hybrid fusion-fission power systems, potentially creating additional commercial opportunities while fusion technology continues to develop.

Investors include Breakthrough Energy Ventures, DCVC, Lowercarbon Capital, Energy Impact Partners, Chevron Technology Ventures, and Bill Gates.

10. Tokamak Energy

U.K.-based Tokamak Energy has raised approximately $284 million.

The company is developing a compact spherical tokamak that uses high-temperature superconducting magnets.

Its ST40 prototype achieved plasma temperatures of approximately 100 million degrees Celsius in 2022. The company is now developing its next-generation system, Demo4, to test its technology under conditions relevant to future fusion power plants.

Tokamak Energy has also developed a business around high-temperature superconducting magnets and is supplying technology for the U.K.’s STEP fusion program.

11. Focused Energy

Germany-based Focused Energy is another company building on technology associated with the National Ignition Facility.

The startup is developing an inertial confinement fusion system that uses laser pulses to compress fusion fuel.

A major challenge is manufacturing fusion fuel targets at enormous scale. Focused Energy is working toward technologies capable of producing large quantities of these precision targets.

The company raised an oversubscribed $240 million Series A, bringing its private capital raised to approximately $277 million. It has also received substantial government grants.

12. Marvel Fusion

Marvel Fusion is developing an inertial confinement fusion approach using powerful lasers and specially engineered silicon nanostructures.

The Munich-based company has raised approximately $208 million.

Its technology is designed to use silicon-based targets that could potentially benefit from manufacturing techniques developed by the semiconductor industry.

Marvel Fusion is working with Colorado State University on a demonstration facility that it expects to have operational by 2027.

13. Type One Energy

Type One Energy is pursuing a stellarator-based approach to fusion power.

The company has raised approximately $174.5 million and is currently working toward a larger Series B financing.

Its planned fusion reactor is expected to generate approximately 350 megawatts of electricity and could be developed at the site of a retired Tennessee Valley Authority coal plant.

Rather than owning and operating every future plant itself, Type One plans to provide technology that utilities can use to build and operate their own fusion facilities.

14. Kyoto Fusioneering

Not every fusion startup is trying to build a complete reactor.

Kyoto Fusioneering is focusing on the equipment and systems surrounding the fusion reactor, often called the balance of plant.

These technologies can include plasma heating equipment, heat extraction systems, power conversion systems, and other components required to turn fusion energy into usable electricity.

The company has raised approximately $121 million, according to FusionX.

Its investors include 31Ventures, In-Q-Tel, JIC Venture Growth Investments, Mitsubishi, and Sumitomo Mitsui Trust Investment.

15. First Light Fusion

U.K.-based First Light Fusion has raised approximately $140 million.

The company is developing an inertial confinement approach to fusion without relying on traditional magnetic confinement.

First Light previously planned to use a two-stage gun to launch a projectile into a fusion target. It has since changed its strategy and is focusing on developing pulsed-power technology and licensing its core technologies to other organizations.

The company is also exploring applications beyond commercial fusion, including science and defense-related uses.

16. Thea Energy

Thea Energy is developing a new approach to stellarator technology.

Traditional stellarators require complex, three-dimensional magnetic coils. Thea Energy believes its system of smaller, digitally controlled magnets can create the required magnetic fields using advanced control software.

The company raised $100 million in Series B funding, bringing its total private capital raised to approximately $120 million.

Its investors include Prelude Ventures, Lowercarbon Capital, Hitachi Ventures, Emerald Technology Ventures, and the U.S. Innovative Technology Fund.

17. Xcimer Energy

Colorado-based Xcimer Energy has raised approximately $101 million.

The startup is developing a high-powered laser system inspired by the National Ignition Facility’s fusion breakthrough.

Xcimer plans to build a 10-megajoule laser system, which would be significantly more powerful than the NIF system used in the landmark experiment.

The company has also developed Phoenix, a prototype laser system that it describes as the most powerful privately owned laser in the world.

Investors include Hedosophia, Breakthrough Energy Ventures, Emerson Collective, Gigascale Capital, and Lowercarbon Capital.

The Future of Fusion Startups

The growing number of heavily funded fusion startups shows how dramatically investor interest in fusion energy has changed.

Companies are pursuing very different strategies. Some are building tokamaks, while others are developing stellarators, laser-driven systems, field-reversed configurations, or magnetized target fusion.

There is no guarantee that any single approach will become commercially successful. Fusion reactors must overcome enormous challenges involving plasma stability, materials, heat management, fuel production, engineering costs, and overall energy efficiency.

However, the growing flow of private capital is allowing startups to test technologies at a speed that was difficult to imagine only a few years ago.

Which Fusion Startup Will Succeed?

The fusion industry is still in its early stages, and it is too soon to know which technology will ultimately dominate.

Commonwealth Fusion Systems and Helion currently stand out because of their enormous funding and ambitious commercialization timelines. Proxima Fusion and Type One Energy represent the growing interest in stellarators, while Pacific Fusion, Focused Energy, Marvel Fusion, Inertia Enterprises, and Xcimer are pursuing approaches inspired by inertial confinement research.

Meanwhile, companies such as Shine Technologies and Kyoto Fusioneering are building businesses around supporting technologies and applications that could generate revenue before commercial fusion electricity becomes widely available.

The next decade could therefore be critical for the fusion industry. If these startups can turn laboratory breakthroughs into reliable, affordable electricity, fusion energy could become one of the most important technologies of the 21st century.

Final Thoughts

Fusion has moved well beyond the stage of being simply a futuristic scientific dream. Billions of dollars in private investment are now supporting companies attempting to turn fusion research into commercial technology.

From Commonwealth Fusion Systems and Helion to Proxima Fusion, General Fusion, Zap Energy, and Xcimer, these companies are taking very different paths toward the same goal: creating a scalable source of fusion power.

As technology improves and more capital enters the sector, the race to commercial fusion is becoming increasingly competitive.

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