Largest SMR Nuclear Energy Companies by Market Cap
NuScale Power (NYSE: SMR) became the first company to receive a U.S. Nuclear Regulatory Commission certified design for a small modular reactor — a distinction that places it at the center of a rapidly developing segment of the nuclear industry. A small modular reactor, or SMR, is a nuclear fission reactor rated at 300 MWe or less, designed to be factory-fabricated and shipped to installation sites as prefabricated modules.
Globally, there are over 120 modular reactor designs at various stages, though only China and Russia have built operational SMRs so far. Most publicly traded SMR companies are listed on U.S. exchanges, where the sector spans pure-play reactor designers, fuel suppliers, and nuclear component manufacturers.
Key publicly traded companies in the SMR space include:
- NuScale Power (NYSE: SMR): Headquartered in Tigard, Oregon, NuScale designs pressurized water SMRs that use passive safety systems relying on natural convection and gravity. It went public in 2022.
- Oklo Inc. (NYSE: OKLO): Based in Santa Clara, California, Oklo develops a liquid-metal-cooled fast reactor called Aurora and commercializes nuclear fuel recycling technology. Sam Altman, co-founder of OpenAI, serves as chairman.
- BWX Technologies (NYSE: BWXT): A nuclear components manufacturer with roots tracing back to the 1800s and involvement in the Manhattan Project. BWX has been engaged in commercial SMR design since 2009.
- Centrus Energy (NYSE American: LEU): The only Western company licensed to produce High-Assay, Low-Enriched Uranium (HALEU), the fuel required by most next-generation reactor designs. Its Ohio plant marked the first domestic HALEU production in over 40 years.
- NANO Nuclear Energy (NASDAQ: NNE): A developer of portable advanced nuclear microreactors, including the KRONOS MMR™ system, and a prospective domestic HALEU supplier.
Notable private companies such as TerraPower (founded by Bill Gates), X-energy, and Kairos Power are not included in this ranking since they are not publicly listed. For related sectors, see largest uranium mining companies and uranium ETFs.
Regulated brokerThe table below ranks the largest SMR nuclear energy companies by market capitalization. It includes only publicly traded companies, and all data — including price and market cap — is updated regularly to reflect current market conditions.
| Stock | Price | Change % | Marketcap |
|---|---|---|---|
 Cameco CCJ | $103.39 | 1.05% | 45.03B |
 BWX Technologies BWXT | $194.14 | 1.90% | 17.79B |
 Oklo OKLO | $52.84 | 5.68% | 9.19B |
 NexGen Energy NXE | $9.63 | 1.23% | 6.37B |
 NuScale Power SMR | $10.17 | 0.66% | 3.52B |
 Uranium Energy UEC | $10.78 | 0.19% | 5.28B |
 Centrus Energy LEU | $162.58 | 1.78% | 3.20B |
 Denison Mines DNN | $3.07 | 0.97% | 2.78B |
NANO Nuclear Energy NNE | $21.16 | 6.49% | 1.10B |
Energy Fuels UUUU | $14.38 | 1.64% | 3.59B |
 enCore Energy EU | $1.33 | 1.85% | 257.36M |
 ASP Isotopes ASPI | $6.25 | 1.30% | 786.90M |
Ur Energy URG | $1.32 | 2.59% | 522.49M |
Uranium Royalty UROY | $2.79 | 0.54% | 408.26M |
Lightbridge Corporation LTBR | $8.71 | 0.58% | 286.08M |
 Rolls-Royce Holdings RR.L | GBp1,415.20 | 0.64% | 117.29B |