Company lists · Data refreshed September 2026

Top 25 Fusion energy companies based in the United States

RevenueBase identified 75 fusion energy companies headquartered in the United States as of September 2026 and tracks 7,425 professional contacts across them, including 2,189 with verified work emails. New York is the largest hub.

This list covers fusion energy companies headquartered in the United States, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Every row shows the company's own description, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 16, 2026.

Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase Smart Search, the natural-language company search RevenueBase customers use to build their own targeted lists and unlock verified emails and direct dials at the companies on them. How these lists are built and judged.

How to read this list HQ checked on every row RevenueBase Smart Search rating on every row Refreshed Sep 16, 2026 86% judged on-target in blind review
75Companies
7,425Contacts tracked
2,189Verified emails
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The 25 largest fusion energy companies based in the United States

Ranked by team size
Top 25 of 75 fusion energy companies based in the United States, ranked by team size, largest first. Data refreshed Sep 16, 2026. RevenueBase Smart Search rates how each company's information relates to fusion energy companies: strong evidence (its own description names it), partial (names part of it), indirect (matched on the rest of its profile rather than the description shown). Click a contact count to view that company's people.
#CompanyRevenueBase Smart SearchHeadquartersEmployeesContacts
1Partial evidenceRockville, MD, United StatesHQ checked Sep 16, 2026501-1,0001,055 contacts →

Partial evidence

“X-energy is delivering the next generation of carbon-free energy by reinventing nuclear power.”

Source: RevenueBase Database · checked Sep 16, 2026
2Strong evidenceDevens, MA, United StatesHQ checked Sep 16, 2026501-1,0001,023 contacts →

Strong evidence

“Commonwealth Fusion Systems (CFS) is on a mission to deliver clean fusion energy to the planet fast enough to matter for humanity’s biggest challenges.”

Source: RevenueBase Database · checked Sep 16, 2026
3Partial evidenceBellevue, WA, United StatesHQ checked Sep 16, 2026501-1,000913 contacts →

Partial evidence

“TerraPower is a leading nuclear innovation company that strives to improve the world through nuclear energy and science.”

Source: RevenueBase Database · checked Sep 16, 2026
4Partial evidenceAlameda, CA, United StatesHQ checked Sep 16, 2026501-1,000485 contacts →

Partial evidence

“Kairos Power has a mission to enable the world’s clean energy transition to improve people’s quality of life while protecting the environment.”

Source: RevenueBase Database · checked Sep 16, 2026
5Partial evidenceEverett, WA, United StatesHQ checked Sep 16, 2026201-500366 contacts →

Partial evidence

“We are a fusion power company based in Everett, WA, with the mission to build the world's first fusion power plant, enabling a future with unlimited clean electricity.”

Source: RevenueBase Database · checked Sep 16, 2026
6Partial evidenceJanesville, WI, United StatesHQ checked Sep 16, 2026201-500297 contacts →

Partial evidence

“Headquartered in Janesville, Wisconsin, SHINE is an industry leader in next-generation fusion, developing innovative fusion-based technology that combines safety, cost-efficiency…”

Source: RevenueBase Database · checked Sep 16, 2026
7Partial evidenceFoothill Ranch, CA, United StatesHQ checked Sep 16, 2026201-500278 contacts →

Partial evidence

“TAE Technologies (pronounced T-A-E) was founded in 1998 to develop commercial fusion power with the cleanest environmental profile.”

Source: RevenueBase Database · checked Sep 16, 2026
8Partial evidenceSanta Clara, CA, United StatesHQ checked Sep 16, 202651-200226 contacts →

Partial evidence

“Oklo's mission is to provide clean, reliable, affordable energy through the deployment of next-generation fast fission technology and recycling nuclear waste.”

Source: RevenueBase Database · checked Sep 16, 2026
9Strong evidenceKnoxville, TN, United StatesHQ checked Sep 16, 2026201-500157 contacts →

Strong evidence

“Type One Energy Group is mission-driven to provide sustainable, affordable fusion power to the world.”

Source: RevenueBase Database · checked Sep 16, 2026
10Partial evidenceEverett, WA, United StatesHQ checked Sep 16, 202651-200148 contacts →

Partial evidence

“Zap is advancing the next generation of nuclear power technology across fusion, fission and hybrid applications.”

Source: RevenueBase Database · checked Sep 16, 2026
11Strong evidenceFremont, CA, United StatesHQ checked Sep 16, 202651-200140 contacts →

Strong evidence

“Pacific Fusion was founded in 2023 to deliver commercial fusion energy to power cities, businesses and homes.”

Source: RevenueBase Database · checked Sep 16, 2026
12Indirect evidenceAustin, TX, United StatesHQ checked Sep 16, 2026201-500119 contacts →

Indirect evidence

“Aalo Atomics designs and builds factory-manufactured nuclear power plants for data centers, industry, and cities.”

Source: RevenueBase Database · checked Sep 16, 2026
13Strong evidenceDenver, CO, United StatesHQ checked Sep 16, 202651-200117 contacts →

Strong evidence

“We're developing an excimer-based laser fusion architecture to commercialize safe, affordable fusion energy while advancing national security.”

Source: RevenueBase Database · checked Sep 16, 2026
14Strong evidenceKearny, NJ, United StatesHQ checked Sep 16, 202651-200101 contacts →

Strong evidence

“Thea Energy is building an economical and scalable fusion energy system utilizing arrays of mass-manufacturable magnets and dynamic software controls.”

Source: RevenueBase Database · checked Sep 16, 2026
15Partial evidenceAustin, TX, United StatesHQ checked Sep 16, 202651-20063 contacts →

Partial evidence

“Last Energy's mission is to decarbonize global energy production and increase access to clean, affordable power.”

Source: RevenueBase Database · checked Sep 16, 2026
16Strong evidenceSeattle, WA, United StatesHQ checked Sep 16, 202651-20054 contacts →

Strong evidence

“Avalanche is a VC-backed, compact fusion energy start-up based in Seattle, WA.”

Source: RevenueBase Database · checked Sep 16, 2026
17Partial evidenceNew York, NY, United StatesHQ checked Sep 16, 202651-20050 contacts →

Partial evidence

“NANO Nuclear Energy Inc.(NASDAQ: NNE) NANO Nuclear Energy Inc.(NASDAQ: NNE) is a North American advanced technology-driven nuclear energy company seeking to become a commercially…”

Source: RevenueBase Database · checked Sep 16, 2026
18Partial evidenceSan Francisco, CA, United StatesHQ checked Sep 16, 202611-5041 contacts →

Partial evidence

“We're building fuel processing technology to make fusion power plants robust, practical and widespread.”

Source: RevenueBase Database · checked Sep 16, 2026
19Partial evidenceMadison, WI, United StatesHQ checked Sep 16, 202611-5037 contacts →

Partial evidence

“Realta Fusion spun out of a groundbreaking physics experiment at the University of Wisconsin-Madison in 2022 and is developing the lowest capital and least complex path to…”

Source: RevenueBase Database · checked Sep 16, 2026
20Indirect evidenceReston, VA, United StatesHQ checked Sep 16, 202611-5025 contacts →

Indirect evidence

“Lightbridge is developing and commercializing next generation nuclear fuel technology that will significantly improve the economics and safety of existing and new reactors, with a…”

Source: RevenueBase Database · checked Sep 16, 2026
21Partial evidenceWashington, DC, United StatesHQ checked Sep 16, 202611-5022 contacts →

Partial evidence

“is meeting America’s long-term energy demands by developing safe, affordable, next-generation nuclear plants at utility scale.”

Source: RevenueBase Database · checked Sep 16, 2026
22Partial evidenceHuntsville, AL, United StatesHQ checked Sep 16, 202611-5016 contacts →

Partial evidence

“Flibe Energy is working to design and develop lithium-fluoride nuclear reactors, which will provide clean energy and valuable materials for the world.”

Source: RevenueBase Database · checked Sep 16, 2026
23Strong evidenceGoleta, CA, United StatesHQ checked Sep 16, 202611-5014 contacts →

Strong evidence

“Blue Laser Fusion Inc.(BLF) is a leading fusion energy company based in Santa Barbara, CA with offices in Silicon Valley and Tokyo, Japan.”

Source: RevenueBase Database · checked Sep 16, 2026
24Partial evidenceWashington, DC, United StatesHQ checked Sep 16, 20261-1014 contacts →

Partial evidence

“The Fusion Industry Association is a registered non-profit organization composed of private companies working to commercialize fusion power.”

Source: RevenueBase Database · checked Sep 16, 2026
25Partial evidenceWilmington, DE, United StatesHQ checked Sep 16, 202611-509 contacts →

Partial evidence

“At Nuclearis, we are pioneering the future of sustainable energy with our innovative nuclear solutions.”

Source: RevenueBase Database · checked Sep 16, 2026

Showing 25 of 75 fusion energy companies based in the United States

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Fusion energy companies based in the United States at a glance

As of Sep 16, 2026
29.5%Verified-email coverage
99.0Average contacts per company
11-50Median size (employees)
8.0%Largest-city concentration · New York
Sep 16, 2026Page data refreshed

Companies by employee count

1-10
31
11-50
21
51-200
12
201-500
5
501-1,000
5
1,001-5,000
1

Email recency for this list is measured worldwide rather than for United States, so it is reported there. Company counts and contact totals on this page are exact for United States, over 75 companies.

How this list was built

Company categories are rarely black and white. RevenueBase reads each company's own description of its business to decide whether it belongs among fusion energy companies, so some rows will be adjacent to the category rather than pure plays. The description and RevenueBase Smart Search rating on every row are there so you can check each match yourself.

Source
The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase Smart Search, the natural-language company search available to every RevenueBase user.
What qualifies
Companies headquartered in the United States whose own description of what they do matches “fusion energy companies”. Matching reads each company's description, not its industry code or its name.
RevenueBase Smart Search
RevenueBase Smart Search is how this list is assembled and how each row is rated. RevenueBase's data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to a category defined in a user's own words. Each row is rated strong evidence (its own description names fusion energy companies), partial evidence (it names part of the category) or indirect evidence (the description shown names none of it and the match rests on the rest of the company's profile). The description supporting each rating is quoted on the row.
What we exclude
Companies whose own description does not clearly place them among fusion energy companies, and records with no verified work email. Companies headquartered outside United States are excluded even when they keep an office there.
Match quality
In blind human judging of this matching method, 86% of matched companies were on target. Expect roughly 1 in 7 rows to be adjacent to the category rather than a pure play. Every row shows the company's own description and its RevenueBase Smart Search rating so you can judge each match yourself. Read the full methodology: how the lists are built, how the judging worked, and what the figure means.
Ranking
Team size, largest first: companies are ordered by the number of professionals RevenueBase tracks at each one. Employee ranges shown are reported bands, for context.
Verification
Every listed company carries at least one verified work email, 2,189 across the full list. Contacts re-verify on a rolling cadence, and each contact's own verification date is shown inside RevenueBase.
Refresh
This page's figures were pulled from the company graph on September 16, 2026. Lists refresh periodically as the graph is re-checked.
Corrections
Wrong category, wrong headquarters, or a company that has closed? Use “Report an issue” on any row. Reports go to the RevenueBase Data Team and feed back into the company graph.

Frequently asked

What is RevenueBase Smart Search?

RevenueBase Smart Search is how RevenueBase decides which companies belong on this list and how strongly each one fits. Its data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to the category the list is about. Each row is rated strong evidence when the company's own description names fusion energy companies, partial evidence when it names part of the category, and indirect evidence when the description shown names none of it and the match rests on the rest of the company's profile.

How many fusion energy companies are there based in the United States?

RevenueBase identified 75 fusion energy companies headquartered in the United States as of September 2026, matched on each company's own description of what it does rather than its industry code.

What is the largest company on this list?

X-Energy, headquartered in Rockville, tops this list with the largest team on record.

Which city has the most fusion energy companies?

New York leads with 6 headquartered companies, followed by Cambridge (4) and San Francisco (3).

How do I get contact information for these companies?

A free RevenueBase account lets you run this exact search and work the top results, verified emails and direct dials included. Upgrading unlocks all 2,189 verified decision-maker contacts tracked across these 75 companies.

How current is this list?

The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on September 16, 2026.

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About this data

RevenueBase is a B2B data infrastructure company. Its company graph covers 60 million companies and 398.9 million professional contacts, with emails verified on a rolling cadence rather than scraped once and left to decay. These company lists are generated directly from that graph with RevenueBase Smart Search, the same natural-language company search every RevenueBase user has: describe a market in plain words, get the companies that match, and add verified emails and direct dials for the people at them. It is the same data that powers RevenueBase's B2B data products, and a free account includes 500 credits to start. How these lists are built and judged.