In recent years, fusion energy has transitioned from a technology often joked about as “a decade away” to an increasingly viable and attractive prospect, attracting numerous investors.
Although the technology is challenging to master and currently expensive to build, fusion energy promises to harness the same nuclear reactions that drive the sun to generate virtually unlimited clean energy on Earth. If startups can build commercially viable fusion power plants, they could potentially disrupt the trillion-dollar energy market.
The wave of optimism driving the fusion industry stems from three major technological advances: more powerful computer chips, advanced AI technology, and powerful high-temperature superconducting magnets. These advances collectively enable more sophisticated reactor designs, better simulations, and more complex control schemes.
Notably, at the end of 2022, a U.S. Department of Energy laboratory announced the achievement of a controlled fusion reaction, producing more energy than the energy injected into the fuel pellet by lasers. This experiment crossed the “scientific break-even point.” While commercial break-even (where the energy produced by the reaction exceeds the energy consumed by the entire facility) is still a long way off, it is a long-awaited milestone that demonstrates the feasibility of the underlying scientific principles.
In recent years, entrepreneurs have built on this momentum, rapidly propelling the private fusion industry forward.
Commonwealth Fusion Systems
Commonwealth Fusion Systems (CFS) has raised approximately one-third of all private investment in fusion companies to date. Its latest funding round, completed in August, raised $863 million, bringing its total raised to nearly $3 billion.
CFS’s Series B2 funding comes four years after its $1.8 billion Series B, which propelled the company to industry leadership. Since then, the startup has been hard at work building Sparc, its first pioneering power plant in Massachusetts, designed to generate “commercially relevant” levels of electricity.
Sparc’s reactor is a doughnut-shaped tokamak. Its D-shaped section is wrapped with high-temperature superconducting tape. When energized, it generates a powerful magnetic field that confines and compresses the ultra-hot plasma. The heat from the reaction is converted into steam to drive a turbine. CFS designed its magnet system in collaboration with MIT, where co-founder and CEO Bob Mumgaard previously researched fusion reactor design and high-temperature superconductors.
Massachusetts-based CFS expects Sparc to be operational by the end of 2026 or early 2027. The company says it will begin construction of the Arc commercial power plant, which will generate 400 megawatts of electricity, in the late 2020s. The facility will be built near Richmond, Virginia, and Google has agreed to purchase half of its output.
CFS is backed by a number of investors, including Breakthrough Energy Ventures, The Engine, and Bill Gates.
TAE
TAE Technologies (formerly Tri Alpha Energy) was founded in 1998 as a spinout from the University of California, Irvine, by Norman Rostoker. It uses a field-inversion configuration, but with a unique twist: after two plasma jets collide in the middle of the reactor, the company bombards the plasma with particle beams, causing it to rotate in a cigar-shaped pattern. This improves plasma stability, buying more time for the fusion reaction to occur and extracting more heat to drive the turbines.
The company raised $150 million in June from existing investors, including Google, Chevron, and New Enterprise. TAE has raised a total of $1.79 billion, according to PitchBook data.
Helion
Helion has the most aggressive timeline of any fusion startup. The company plans to generate electricity from its reactor by 2028. Its first customer is Microsoft.
Helion, based in Everett, Washington, uses a reactor called a field-reversal configuration. Magnets surround a reaction chamber that resembles an hourglass, with a bulge where the two sides meet. At either end of the hourglass, they spin the plasma into a donut shape, shooting it toward each other at speeds exceeding 1 million mph. When they collide in the middle, additional magnets help induce fusion. When fusion occurs, it strengthens the plasma’s own magnetic field, inducing currents within the reactor’s magnetic coils. This electricity is then harvested directly from the machine.
The company raised $425 million in January 2025, around the same time it launched its prototype reactor, Polaris. According to PitchBook data, Helion has raised $1.03 billion. Investors include Sam Altman, Reid Hoffman, KKR, BlackRock, Peter Thiel’s Mithril Capital Management, and Capricorn Investment Group.
Shine Technologies
Shine Technologies is taking a cautious and potentially pragmatic approach to generating fusion energy. Because fusion power plants are still years away, the company is initially focusing on selling neutron test and medical isotopes. More recently, it has been developing methods for recycling radioactive waste. Shine has not yet chosen a specific approach for its future fusion reactors, but says it is developing the necessary skills for that time.
According to PitchBook data, the company has raised a total of $778 million. Investors include Energy Ventures Group, Koch Disruptive Technologies, Nucleation Capital, and the Wisconsin Alumni Research Foundation.
Pacific Fusion
Pacific Fusion launched strongly with $900 million in Series A funding, a significant sum even among well-funded fusion startups. The company will use inertial confinement to achieve fusion, but rather than lasers to compress the fuel, it will use coordinated electromagnetic pulses. The key is timing: all 156 impedance-matched Marx generators need to generate 2 terawatts of power within 100 nanoseconds, and these pulses need to converge simultaneously on the target.
The company is led by Eric Lander, the scientist who led the Human Genome Project, as CEO, and Will Regan as president. While Pacific Fusion’s funding is substantial, the startup won’t receive all the money all at once. Instead, investors will pay it in installments as the company reaches designated milestones, an approach common in the biotech sector.
General Fusion
Now in its third decade, General Fusion has raised $462.5 million, according to PitchBook data. The Richmond, British Columbia-based company was founded in 2002 by physicist Michel Laberge, who wanted to demonstrate a different fusion approach, magnetized target fusion (MTF). Investors include Jeff Bezos, Temasek, BDC Capital, and Chrysalix Venture Capital.
In General Fusion’s reactor, a liquid metal wall surrounds a chamber where plasma is injected. A piston surrounding the wall pushes inward, compressing the plasma inside and triggering a fusion reaction. The resulting neutrons heat the liquid metal, which circulates through a heat exchanger to produce steam that drives a turbine.
General Fusion, The Latest News has learned, was facing difficulties in the spring of 2025. The company ran out of cash while building the LM26 facility, which it had hoped to break even in 2026. Just days after reaching a key milestone, the company laid off 25% of its staff. CEO Greg Twinney penned an open letter pleading with investors for funds.
In August, investors responded, injecting $22 million in a round of financing that one investor described as “the minimum capital needed to keep General Fusion afloat.”
Tokamak Energy
Tokamak Energy takes the conventional tokamak design—a doughnut shape—and compresses it, reducing its aspect ratio so that the outer boundary begins to resemble a sphere. Like many other tokamak-based startups, the company uses high-temperature superconducting magnets (rare earth barium copper oxide, or REBCO) of the type. Because its design is more compact than traditional tokamaks, it requires fewer magnets, reducing costs.
The Oxfordshire, England-based startup’s ST40 prototype, which looks like a large steampunk Fabergé egg, produced an ultra-hot 100 million-degree Celsius plasma in 2022. Its next-generation Demo 4, currently under construction, is designed to test the company’s magnets in “fusion power plant-related scenarios.” Tokamak Energy raised $125 million in November 2024 to continue its reactor design work and expand its magnet business.
According to PitchBook data, the company has raised a total of $336 million from investors, including Future Planet Capital, In-Q-Tel, Midven, and Capri-Sun founder Hans-Peter Wild.
Zap Energy
Zap Energy does not use high-temperature superconducting magnets or ultra-powerful lasers to confine plasma. Instead, it “shocks” the plasma with an electric current and then generates its own magnetic field. This field compresses the plasma by about 1 millimeter, at which point ignition occurs. Neutrons released by the fusion reaction bombard the liquid metal blanket surrounding the reactor, heating it up. The liquid metal then circulates through a heat exchanger, generating steam that drives a turbine.
Like Helion, Zap Energy is headquartered in Everett, Washington, and has raised $327 million, according to PitchBook data. Backers include Bill Gates’ Breakthrough Energy Ventures, DCVC, Lowercarbon, Energy Impact Partners, Chevron Technology Investments, and Bill Gates as an angel investor.
Proxima Fusion
Most investors favor large startups pursuing tokamaks or some form of inertial confinement. But stellarators have shown great promise in scientific experiments, including Germany’s Wendelstein 7-X reactor.
Proxima Fusion, however, is bucking this trend, attracting €130 million in Series A funding, bringing its total raised to over €185 million. Investors include Balderton Capital and Cherry Ventures.
Stellarators, like tokamaks, use powerful magnets to confine plasma in a doughnut shape. But they have a twist—literally. Instead of forcing the plasma into a contrived doughnut shape, stellarators twist and bulge to accommodate the plasma’s characteristics. The result should be a stable plasma for longer periods, increasing the chances of a fusion reaction.
Marvel Fusion
Marvel Fusion follows the inertial confinement approach, the same basic technology used by the National Ignition Facility in the United States to demonstrate that controlled nuclear fusion reactions can produce more energy than needed to initiate them. Marvel fires powerful lasers at a target embedded in silicon nanostructures, which cascade under bombardment, compressing the fuel to the point of ignition. Because the target is made of silicon, manufacturing should be relatively simple, leveraging decades of experience in semiconductor manufacturing.
This inertial confinement fusion startup is collaborating with Colorado State University to build a demonstration facility, expected to be operational by 2027. Munich-based Marvel has raised a total of $161 million from investors, including b2venture, Deutsche Telekom, Earlybird, HV Capital, and angel investors Taavet Hinrikus and Albert Wenger.
First Light
First Light abandoned its pursuit of fusion energy in March 2025, instead becoming a technology supplier to fusion startups and other companies. The startup previously pursued a method called inertial confinement, which compresses fusion fuel pellets until ignition.
Based in Oxfordshire, England, First Light has raised $140 million from investors, including Invesco, IP Group, and Tencent, according to PitchBook data.
Xcimer
While no aspect of fusion is simple, Xcimer has taken a relatively straightforward approach: following the fundamental science behind the groundbreaking net-positive experiment at the National Ignition Facility (NIF) and redesigning the technology that underpins it from the ground up. The Colorado-based startup is targeting a 10-megajoule laser system, five times more powerful than the historic NIF facility. A molten salt wall surrounds the reactor, absorbing heat and protecting the first solid wall from damage.
Xcimer, founded in January 2022, has raised $109 million from investors including Hedosophia, Breakthrough Energy Ventures, Emerson Collective, Gigascale Capital, and Lowercarbon Capital, according to PitchBook data. The company is closely monitoring its potential role in future energy markets.
