Over $15 billion has flooded into private fusion companies. Who’s closest to the grid?
Fusion energy has long been the province of governments and national laboratories — ITER, the €25 billion international tokamak under construction in France, being the paradigmatic example. But over the past decade, a wave of well-funded private companies has entered the field, convinced that faster iteration, novel technologies, and commercial urgency can outpace government programs. As of September 2025, private fusion investment reached $15 billion globally according to Fusion for Energy, the EU body managing ITER’s construction — and the race is intensifying.
Commonwealth Fusion Systems: The MIT Spinout
Commonwealth Fusion Systems (CFS), which spun out of MIT in 2018, is the best-funded private fusion company with nearly $3 billion raised to date — including an $863 million Series B2 round in August 2025 that was described as oversubscribed. CFS is building SPARC, a compact tokamak demonstration machine, at a 65%-complete facility in Devens, Massachusetts. SPARC is designed to achieve net energy gain (more fusion energy out than heating energy in) as early as 2027. The secret to SPARC’s compact design is its use of high-temperature superconducting (HTS) magnets, which can produce magnetic fields several times stronger than previous superconducting magnets at a fraction of the cost — allowing a much smaller, cheaper reactor to achieve the same plasma performance as larger, costlier machines. CFS has already signed a Power Purchase Agreement with Google to supply 200 MW of electricity from its first ARC commercial power plant in Virginia, targeted for the early 2030s. Italian energy company ENI has committed $1 billion to purchase power from CFS. New investors in the Series B2 include Nvidia, Morgan Stanley, and a consortium of 12 Japanese energy and financial firms.
Helion Energy: Direct Electricity from Fusion
Helion, based in Everett, Washington, is pursuing a radically different approach. Its field-reversed configuration (FRC) reactor fires two rings of plasma from opposite ends of an elongated chamber, merging them in the center and then compressing them magnetically until fusion occurs. Unlike most fusion designs, which convert fusion heat to steam to drive a turbine, Helion’s plasma expands outward after fusion, pushing back against the confining magnets and generating electricity directly via induction — analogous to regenerative braking in an electric vehicle. Helion has raised over $1 billion, including a $375 million personal investment from OpenAI CEO Sam Altman. The company has signed a landmark Power Purchase Agreement with Microsoft to supply 50 MW of electricity from a plant in Washington state by 2029 — the first commercial fusion power contract in history. A second 500 MW PPA with steelmaker Nucor, targeting 2030, adds further credibility. Construction of the Orion reactor plant began in July 2025. Helion’s seventh-generation Polaris prototype, completed in 2024, is expected to demonstrate electricity generation from fusion in 2025.
TAE Technologies: The Aneutronic Ambition
TAE Technologies, founded in 1998 and the longest-running private fusion company, has raised $1.79 billion and is pursuing the most technically ambitious fusion fuel: proton-boron (pB11). Unlike deuterium-tritium (D-T) fusion, which produces high-energy neutrons that irradiate the reactor structure, pB11 fusion produces primarily alpha particles — essentially helium nuclei — with minimal neutron production. This ‘aneutronic’ approach could dramatically reduce reactor activation and waste. In December 2025, TAE announced a merger with Trump Media & Technology Group in an all-stock transaction valuing the combined company at $6 billion, creating one of the world’s first publicly traded fusion energy companies. TAE plans to begin building the world’s first utility-scale fusion power plant in 2026.
The Broader Field
More than 50 fusion startups are active globally, representing a remarkable diversity of technical approaches. Pacific Fusion launched in 2024 with a $900 million Series A — using coordinated electromagnetic pulses to achieve ICF-style implosions. Zap Energy uses a z-pinch approach: running an electric current through a plasma column generates its own confining magnetic field, compressing the plasma. General Fusion, based in Canada, is testing its magnetized target fusion machine LM26, which uses mechanical compression of liquid metal to squeeze a plasma. Proxima Fusion, which raised $150 million in 2025, is developing a stellarator-based power plant targeting the 2030s.
The Funding Landscape
The fusion industry raised approximately $2.6 billion in the 12 months ending July 2025, recovering from a trough of roughly $900 million in 2023. China is estimated to be spending $3 billion per year in government fusion funding — more than twice the U.S. total in 2024 — and holds more fusion energy patents than any other country. The UK government committed £2.5 billion ($3.37 billion) for fusion energy over five years in June 2025, taking leadership in European government fusion funding.
The private fusion race is no longer a matter of ‘will it ever happen’ but ‘who gets there first and by what route.’ The early 2030s are shaping up as the decisive decade.