Over the last several years, fusion power has evolved from a running joke—always a decade away—into a tangible, tantalizing technology that has drawn investors off the sidelines. The technology remains challenging to master and expensive to build, but fusion promises to harness the nuclear reaction that powers the sun to generate nearly limitless energy on Earth. If fusion startups funding over 100 million can complete commercially viable fusion power plants, they have the potential to upend trillion-dollar markets.
A wave of optimism is buoying the fusion industry, driven by three key advances: more powerful computer chips, more sophisticated AI, and powerful high-temperature superconducting magnets. Together, they have enabled more advanced reactor designs, better simulations, and more complex control systems.
In late 2022, a U.S. Department of Energy lab announced it had produced a controlled fusion reaction that generated more power than the lasers imparted to the fuel pellet. That experiment crossed scientific breakeven, and while it remains far from commercial breakeven—where the reaction produces more than the entire facility consumes—it proved the underlying science is sound.
Founders have built on that momentum, pushing the private fusion industry forward at a rapid pace. Below is a list of every fusion startups funding over 100 million in committed capital from private investors, according to data provided to TechCrunch by FusionX.
Commonwealth Fusion Systems
Commonwealth Fusion Systems (CFS) has raised approximately one-third of all private capital invested in fusion startups funding over 100 million to date. Its latest round, which closed in July, added $1 billion, bringing its total raised to $3.94 billion, according to FusionX.
CFS surged into the lead in 2021 with a $1.8 billion Series B. Since then, the startup has been building Sparc in Massachusetts, its first-of-a-kind power plant intended to produce power at what it calls “commercially relevant” levels. The company says Sparc should reach scientific breakeven—Q > 1—sometime in 2027.
Sparc uses a tokamak design that resembles a doughnut. Its D-shaped cross section is wound with high-temperature superconducting tape, which generates a powerful magnetic field to contain and compress superheated plasma. Heat from the reaction converts to steam to power a turbine. CFS designed its magnets with MIT, where co-founder and CEO Bob Mumgaard worked on fusion reactor designs and high-temperature superconductors.
CFS expects Sparc to be operational in late 2026 or early 2027. Later this decade, the company will begin constructing Arc, its commercial power plant producing 400 megawatts of electricity, near Richmond, Virginia. Google has agreed to buy half its output. Investors include Breakthrough Energy Ventures, The Engine, Bill Gates, and others.
Helion
Of all fusion startups funding over 100 million, Helion has the most aggressive timeline. The company plans to produce electricity from its reactor in 2028, with Microsoft as its first customer.
Helion, based in Everett, Washington, uses a field-reversed configuration reactor, where magnets surround a reaction chamber shaped like an hourglass with a bulge where the two sides meet. At each end, the reactor spins plasma into doughnut shapes that collide in the middle at more than 1 million mph. Additional magnets induce fusion, boosting the plasma’s magnetic field and generating electrical current harvested directly from the machine.
The company most recently raised $465 million in June in a Series G that valued the company at $15.5 billion. Its previous round, announced in January 2025, totaled $425 million. Altogether, Helion has raised $3.2 billion in committed capital, according to FusionX. Investors include Sam Altman, SoftBank Vision Fund 2, Reid Hoffman, KKR, BlackRock, Peter Thiel’s Mithril Capital Management, and Capricorn Investment Group.
TAE Technologies
Founded in 1998, TAE Technologies (formerly Tri Alpha Energy) spun out of the University of California, Irvine by Norman Rostoker. It uses a field-reversed configuration with a twist: after two plasma shots collide, the company bombards the plasma with particle beams to keep it spinning in a cigar shape, improving stability and allowing more time for fusion.
In December 2025, TAE announced it would merge with Trump Media & Technology Group in an all-stock transaction valuing the combined company at $6 billion. TAE would receive $200 million plus another $100 million upon filing SEC paperwork. The combined entity would be led by co-CEOs: TAE CEO Michl Binderbauer and Trump Media’s interim CEO Kevin McGurn.
The fusion startups funding over 100 million previously raised $150 million in June 2025 from existing investors including Google, Chevron, and New Enterprise. Prior to the merger, TAE had raised $1.65 billion, according to FusionX.
Pacific Fusion
Pacific Fusion launched with a Series A exceeding $1 billion, according to TechCrunch—a massive sum even among well-funded fusion startups funding over 100 million. The company uses inertial confinement with coordinated electromagnetic pulses instead of lasers. All 156 impedance-matched Marx generators must produce 2 terawatts for 100 nanoseconds, converging on the target simultaneously.
The company is led by CEO Eric Lander, who led the Human Genome Project, and chief scientist Will Regan. Pacific Fusion’s funding is paid in tranches upon achieving specified milestones, a common biotech approach.
Proxima Fusion
Most investors have favored tokamak designs or inertial confinement, but stellarators have shown great promise in scientific experiments like the Wendelstein 7-X reactor in Germany. Proxima Fusion is capitalizing on its proximity to that success, raising more than $682.9 million across rounds, according to FusionX. Its most recent round, announced in July, valued the company at $2.7 billion. Investors include Google, RWE, Balderton Capital, Cherry Ventures, East X Ventures, and XTX Ventures.
Stellarators are similar to tokamaks but with a literal twist: rather than forcing plasma into a human-designed ring, they twist and bulge to accommodate plasma quirks, resulting in more stable plasma for longer fusion reactions. Proxima plans to complete Alpha, its net-energy demonstrator, in the early 2030s, and Stellaris, its commercial power plant, later that decade.
Shine Technologies
Shine Technologies is taking a cautious approach to fusion power. Selling electrons from a fusion plant is years away, so instead it sells neutron testing and medical isotopes and is developing a way to recycle radioactive waste. Shine hasn’t picked a reactor approach, instead developing necessary skills for the future.
The company has raised $1 billion, according to PitchBook. Its most recent $240 million round in February was led by NantWorks with participation from Deerfield Management, Fidelity Management & Research Company, Oaktree Capital Management, Pelican Energy Partners, and Sumitomo Corporation of Americas.
Inertia Enterprises
Only one fusion experiment, the National Ignition Facility (NIF), has surpassed scientific breakeven, and its chief scientist, Annie Kritcher, is part of Inertia Enterprises’ founding team alongside Stanford professor Mike Dunne and Twilio co-founder Jeff Lawson. In April, the startup signed agreements to commercialize NIF technology.
Inertia uses lasers to bombard fusion fuel pellets, an inertial confinement design similar to Kritcher’s successful NIF approach. The company emerged from stealth in February with $450 million in Series A funding led by Bessemer Venture Partners with participation from GV, Modern Capital, and Threshold Ventures.
General Fusion
Now in its third decade, General Fusion has raised over $442 million, according to FusionX data. The Richmond, British Columbia-based company was founded in 2002 by physicist Michel Laberge to prove 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. Pistons push the wall inward, compressing plasma to spark fusion. The resulting neutrons heat the liquid metal, which circulates through a heat exchanger to generate steam.
General Fusion hit a rough patch in spring 2025, running short of cash while building LM26. Days after a key milestone, it laid off 25% of its staff. CEO Greg Twinney penned an open letter pleading for funding. In August 2025, investors injected $22 million in a pay-to-play round. Then in November, the company raised $51.1 million in SAFE notes from nearly 70 investors, the Globe and Mail reported.
In January, General Fusion announced it would go public via reverse merger with a SPAC, listing on Nasdaq on July 13, 2026, netting $127 million, per FusionX.
Zap Energy
Zap Energy doesn’t use magnets or lasers to confine plasma. Instead, it zaps plasma with an electric current, generating a magnetic field that compresses plasma to about 1 millimeter for ignition. Neutrons from fusion bombard a liquid metal blanket, heating it to produce steam for a turbine.
The startup announced a partial pivot in April, saying it would pursue nuclear fission in addition to fusion while exploring a hybrid power plant blending both. It also hired a new CEO, Zabrina Johal, with fission industry expertise, aiming to generate revenue earlier than fusion alone.
The Everett, Washington-based company has raised $325 million, according to FusionX. Backers include Bill Gates’ Breakthrough Energy Ventures, DCVC, Lowercarbon, Energy Impact Partners, Chevron Technology Ventures, and Bill Gates as an angel.
Tokamak Energy
Tokamak Energy takes the tokamak design and squishes it, reducing its aspect ratio until it resembles a sphere. The company uses high-temperature superconducting magnets (REBCO variety), and its compact design requires fewer magnets, reducing costs.
The Oxfordshire, U.K.-based startup’s ST40 prototype generated a 100-million-degree Celsius plasma in 2022. Its next generation, Demo 4, is under construction to test magnets in “fusion power plant-relevant scenarios.” Tokamak Energy raised $125 million in November 2024 and in April announced it would supply magnets for the U.K.’s STEP Fusion program. Total raised stands at $284 million, according to FusionX.
Focused Energy
Germany-based Focused Energy traces its lineage to NIF, using laser pulses to compress fuel targets. The company hired Debbie Callahan, who helped design NIF’s fuel target, as chief strategy officer to figure out how to mass manufacture targets at nearly 1 million per day.
Focused Energy raised an oversubscribed $240 million Series A in June, bringing total private capital to $277 million, according to FusionX, plus $200 million in grants. Investors include the German Federal Agency for Breakthrough Innovation (SPRIND), Prime Movers Lab, and utility RWE, which granted access to a decommissioned fission plant.
Marvel Fusion
Marvel Fusion uses inertial confinement, firing powerful lasers at a target embedded with silicon nanostructures that cascade under bombardment, compressing fuel to ignition. Silicon targets should be relatively simple to manufacture, leveraging the semiconductor industry’s experience.
The Munich-based startup is building a demonstration facility with Colorado State University, expected operational by 2027. Marvel has raised $208 million from investors including b2venture, Deutsche Telekom, Earlybird, and HV Capital.
Type One Energy
Stellarator startup Type One Energy is building a fusion reactor on the site of a retired Tennessee Valley Authority (TVA) coal power plant. The magnetic confinement device is expected to generate 350 megawatts of electricity by the mid-2030s.
Unlike other startups, Type One plans to sell key technology to organizations like TVA, allowing them to build, own, and operate the equipment. Type One has raised $174.5 million to date, according to FusionX, and is currently raising a $250 million Series B.
Kyoto Fusioneering
Kyoto Fusioneering develops balance-of-plant components—the parts outside the reactor, from gyrotrons that heat plasma to heat extraction systems. The company bets that if even one fusion startups funding over 100 million succeeds, the industry will need a supplier for these components and integration expertise.
Venture capitalists agree, having invested $121 million in Kyoto Fusioneering, per FusionX. Investors include 31Ventures, In-Q-Tel, JIC Venture Growth Investments, Mitsubishi, and Sumitomo Mitsui Trust Investment.
First Light Fusion
First Light Fusion doesn’t use magnets but instead inertial confinement, compressing fusion fuel pellets until ignition. Most attempts use lasers following NIF’s lead, but First Light had previously planned to fire a projectile from a two-stage gun before dropping those plans.
The Oxfordshire, U.K.-based company says it is offering core technologies to other inertial confinement power plant builders and is planning “pulsed power capability that would act as our demonstrator plant but would have other science and defense applications.” First Light has raised $140 million, per FusionX data.
Thea Energy
Thea Energy is betting pixel-inspired magnets will help it build a stellarator for less money. Stellarators can keep plasmas burning for long periods, but require twisty magnetic fields. Most stellarators build magnets mimicking that complex shape, but Thea uses dozens of smaller magnets and control software to create the necessary kinks.
In May, Thea raised $100 million in a Series B led by the U.S. Innovative Technology Fund, two years after a $20 million Series A, for total private capital of $120 million.
Xcimer
Xcimer follows the basic science behind NIF’s net-positive experiment and redesigns the underlying technology. The Colorado-based startup plans a 10-megajoule laser system, 5x more powerful than NIF. Molten salt walls surround the reaction chamber, absorbing heat and protecting the first solid wall. In June, Xcimer turned on Phoenix, a prototype system it calls the most powerful privately owned laser in the world.
Founded in July 2022, Xcimer has raised $101 million from investors including Hedosophia, Breakthrough Energy Ventures, Emerson Collective, Gigascale Capital, and Lowercarbon Capital.
