Nuclear fusion startups have raised $7.1 billion to date, according to data provided by FusionX to TechCrunch, with most of the capital going to a limited number of companies. This sector features companies using different technologies to achieve a single goal: producing energy from the nuclear reaction that powers the sun, then converting it into electricity that can be sold commercially.
Nuclear fusion was mocked for years because of repeated promises that it was still “a decade away,” but it has become more attractive to investors with the development of computer chips, artificial intelligence, and high-temperature superconducting magnets. These advances have contributed to improvements in reactor designs, simulations, and control systems.
At the end of 2022, a laboratory affiliated with the U.S. Department of Energy announced a controlled fusion reaction that produced more energy than the energy delivered by the lasers to the fuel capsule. This achieved what is known as scientific breakeven, but it is not equivalent to commercial breakeven, which requires the reaction to produce more energy than the entire facility consumes.
Companies With the Largest Funding
- Commonwealth Fusion Systems: Raised approximately $3.94 billion, or nearly one-third of the private capital invested in fusion companies. A round closed in July added $1 billion to its funding. In Massachusetts, the company is building the Sparc tokamak reactor and expects to reach scientific breakeven in 2027, with the reactor becoming operational in late 2026 or early 2027. It later plans to build the 400-megawatt Arc plant near Richmond, Virginia, with an agreement for Google to purchase half of its output.
- Helion: Raised $3.2 billion in committed capital and has adopted the most aggressive timeline among the companies, planning to produce electricity from its reactor in 2028 for its first customer, Microsoft. The company uses a field-reversed configuration and raised $465 million in a Series G round in June, after which the company was valued at $15.5 billion.
- TAE Technologies: Raised $1.65 billion before announcing its December 2025 merger with Trump Media & Technology Group in an all-stock deal that valued the combined entity at $6 billion. It uses a field-reversed configuration with particle beams to help stabilize the plasma.
- Pacific Fusion: Began with a Series A round exceeding $1 billion. It uses inertial confinement based on coordinated electromagnetic pulses instead of lasers, with 156 pulsed generators intended to produce a total power of terawatts for 100 nanoseconds.
- Proxima Fusion: Raised more than $682.9 million and is valued at $2.7 billion after its latest round. It is developing stellarator reactors, with a plan to complete the Alpha prototype in the early 2030s and the commercial Stellaris plant later in the same decade.
Alternative Technologies and Paths
Not all companies are pursuing the traditional tokamak design. Shine Technologies has raised $1 billion and is currently focused on testing neutrons and medical isotopes and recycling radioactive waste, without selecting a specific technology for a future fusion reactor. Inertia Enterprises, whose founding team includes Annie Kritcher, the chief scientist for the National Ignition Facility experiment, raised $450 million in a Series A round and uses lasers to bombard fusion fuel pellets.
General Fusion uses a magnetized target fusion approach, with a liquid-metal wall and pistons that compress the plasma. The company has raised more than $442 million, but it faced a cash crisis in 2025 and cut 25% of its staff. It later raised $22 million in a round linked to investor participation, followed by $51.1 million in SAFE notes, before being listed on Nasdaq on July 13, 2026, after a reverse merger with a special purpose acquisition company in a deal that provided it with $127 million.
Zap Energy relies on an electric current that confines the plasma and generates its own magnetic field. In April, it announced a partial shift toward nuclear fission alongside fusion while exploring a hybrid plant. It has raised $325 million. Tokamak Energy is developing a compact, more spherical tokamak and has used REBCO superconducting magnets. It has raised $284 million and is building the Demo 4 prototype. In April, it also said it would supply magnets for the UK’s STEP Fusion program.
Lasers, Stellarators, and Supply Chains
Focused Energy, based in Germany, is seeking to develop fuel targets that can be manufactured at a rate of approximately one million targets per day. It raised $240 million in a Series A round, bringing its private capital to $277 million, in addition to $200 million in grants. Marvel Fusion uses lasers with targets containing silicon nanostructures and is building an experimental facility in cooperation with Colorado State University that it expects to operate in 2027; it has raised $208 million.
Type One Energy plans to build a 350-megawatt stellarator reactor at the site of a retired TVA coal plant, targeting operation in the mid-2030s. The company has raised $174.5 million and is currently raising $250 million for a Series B round. Thea Energy is also betting on the use of dozens of small magnets and control software to form the complex field required for a stellarator, and has raised $120 million.
On the plant components side, Kyoto Fusioneering has raised $121 million to develop what is known as the balance of plant, including heat extraction systems and plasma-heating components. The company believes that the success of any commercial fusion technology will create demand for suppliers capable of integrating these components.
Other Companies That Surpassed the $100 Million Mark
- First Light Fusion: Raised $140 million and abandoned plans to use a two-stage gun to launch a projectile. It is offering its core technologies to companies building inertial fusion plants.
- Xcimer: Raised $101 million and is developing a 10-megajoule laser system, five times more powerful than the National Ignition Facility system. It also operated its first Phoenix prototype in June.
- These companies: Announced timelines range from producing electricity in 2028, to building experimental prototypes during the next decade, to reaching commercial plants in the mid-2030s. The diversity of approaches indicates that the sector has not yet determined which technology will be able to produce commercial-scale fusion energy.