7 Best Small-Cap Nuclear & SMR Stocks — June 2026

Nuclear is the energy story that 2025 finally took seriously. Microsoft signed a 20-year PPA to restart Three Mile Island Unit 1; Amazon, Google, and Meta have collectively committed to multi-gigawatt SMR (small modular reactor) capacity over the next decade. Behind that headline demand sits a real supply problem: the US has essentially no domestic HALEU enrichment capacity, ISR uranium production runs at a fraction of 1980s levels, and the SMR licensing pathway under NRC Part 53 is still being walked for the first time.

The big-cap nuclear names (Constellation, Vistra, BWXT, Cameco) capture the obvious headline trade. The small-cap layer (market cap <$2B) is where the fuel-cycle bottlenecks and next-generation reactor IP live. Below: seven US/Canada-listed names with current operating or development exposure to the nuclear build-out — ranked by our May 24 score snapshot.

Why the Small-Cap Nuclear Setup Is Different This Cycle

Three things changed between 2022 and 2026 that re-rate the small-cap nuclear universe:

1. AI datacenter load growth is structural. Hyperscalers have committed to >40 GW of new generation capacity by 2030, and SMRs are the only zero-carbon option that scales without transmission-queue dependency.
2. HALEU supply is the binding constraint. Every advanced reactor design (NuScale, X-energy, TerraPower, Oklo, Kairos, NNE) needs 5-20% enriched uranium. Russia was the only commercial supplier; the US DOE's HALEU consortium is now standing up domestic capacity.
3. The NRC's Part 53 framework is being walked. Licensing timelines for advanced reactors are still slow but the framework itself is no longer the bottleneck — it is a navigable process.

The bear case: SMR commercial deployment is a 2028-2032 story, not 2026. Most of the names below are pre-revenue or pre-positive-FCF, so sizing should match the multi-year option-value setup.

The Names

ASPI — ASP Isotopes Inc.

Score: 61.1 (SOLID) | Market cap: $0.64B | Revenue YoY: +475.5% | Rule of 40: 235.7 | Cash runway: 91 months

ASP Isotopes runs a laser-based isotope-separation platform — most importantly for HALEU (high-assay low-enriched uranium), the 5-20% enrichment grade that every advanced reactor and SMR design requires. The only commercial-scale HALEU production today is in Russia; US and European SMR roadmaps are explicitly bottlenecked on domestic supply. ASPI's South Carolina facility is on the DOE's HALEU consortium shortlist. Q1 2026 revenue exploded off a small base (medical isotope shipments to PET/CT customers), which is what drives the +475% YoY and the Rule-of-40 reading north of 200 — these numbers will compress as the comp base normalizes. The thesis is durability of the HALEU contract pipeline, not the trailing print. → See full ASPI score card

ISOU — IsoEnergy Ltd.

Score: 46.2 (SPECULATIVE) | Market cap: $0.64B | Revenue YoY: n/a (pre-revenue) | Rule of 40: n/a | Cash runway: 59 months

IsoEnergy is a uranium developer with high-grade assets in Saskatchewan's Athabasca Basin — the Hurricane deposit hosts grades 30-100× the global average, which transforms project economics if permitting and construction execute. Pre-revenue and pre-production, so the score reflects asset quality and balance sheet rather than operating cash flow. Cash runway ~59 months gives comfortable headroom to advance Hurricane through PEA into a feasibility study without dilution pressure. The catalyst path is a 2026-2027 PEA upgrade and a US listing-quality re-rating. → See full ISOU score card

NNE — Nano Nuclear Energy Inc.

Score: 43.1 (SPECULATIVE) | Market cap: $1.22B | Revenue YoY: n/a (pre-revenue) | Rule of 40: n/a | Cash runway: 124 months

Nano Nuclear Energy is the closest thing to a US-listed SMR pure-play under $2B — micro-reactor designs (KRONOS, ZEUS) for off-grid, defense, and remote-industrial applications, plus a HALEU-fuel-fabrication sleeve. No revenue yet; the score reflects cash position (~$170M post the 2025 raises) and design-progression milestones rather than trailing fundamentals. Runway ~10 years if burn stays disciplined. The honest read is that NNE is a 5-10 year option on the US micro-reactor licensing pathway; sizing should match that timeframe. → See full NNE score card

LTBR — Lightbridge Corporation

Score: 34.1 (HIGH RISK) | Market cap: $0.41B | Revenue YoY: n/a (pre-revenue) | Rule of 40: n/a | Cash runway: 170 months

Lightbridge develops a proprietary metallic-fuel design for existing PWRs and next-gen reactors — the pitch is higher uranium-utilization efficiency and longer cycles than ceramic UO₂ fuel. A 2023 framework agreement with Idaho National Laboratory advanced the irradiation-testing program; the 2026-2028 path is loop-test data leading to a Tech Readiness Level 6 milestone. Cash runway ~14 years is extraordinary for a development-stage company — Lightbridge can afford to wait for the industry to come to it. HIGH-RISK score reflects pre-commercial status, not balance-sheet risk. → See full LTBR score card

EU — enCore Energy Corp.

Score: 38.2 (HIGH RISK) | Market cap: $0.36B | Revenue YoY: -26.0% | Rule of 40: -178.4 | Cash runway: 25 months

enCore Energy operates in-situ-recovery (ISR) uranium production in Texas (Rosita, Alta Mesa) — ISR is the lower-cost, lower-disturbance method that has carried US uranium output since the 1990s. 2025 production ramp underperformed guidance, which is why revenue YoY shows -26% and the score sits in HIGH-RISK. The thesis is operational normalization: Alta Mesa restart and Rosita wellfield expansion are 2026 H2 milestones. Cash runway ~25 months gives execution window, but another miss likely triggers a raise. → See full EU score card

UROY — Uranium Royalty Corp.

Score: 31.6 (HIGH RISK) | Market cap: $0.56B | Revenue YoY: -63.5% | Rule of 40: -94.3 | Cash runway: 7 months

Uranium Royalty Corp owns royalty and streaming interests in producing and development-stage uranium projects — a financial-exposure play to the uranium price without operating risk. Revenue YoY -63% reflects timing of physical-uranium sales (URC holds physical pounds as an investment), not a structural problem. Cash runway is the binding constraint here — URC's treasury thinned through 2025; another acquisition or physical-uranium purchase would require issuance. The royalty model is unique in the small-cap uranium universe, which is the structural argument for owning the name. → See full UROY score card

URG — Ur Energy Inc

Score: 29.4 (HIGH RISK) | Market cap: $0.70B | Revenue YoY: -19.3% | Rule of 40: -274.3 | Cash runway: 34 months

Ur-Energy runs the Lost Creek ISR uranium mine in Wyoming — one of only two US ISR operations with production-level deliveries through 2025. Revenue contraction (-19% YoY) and a deeply negative Rule-of-40 reflect operating-cost pressure as the deeper portions of the wellfield produce at lower grades. The 2026 catalyst is the Shirley Basin restart, which adds a second production source and improves blended cash cost. Cash runway ~34 months supports the build without urgent dilution. → See full URG score card

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How to Think About Position Sizing

Small-cap nuclear is a barbell. The fuel-cycle names (ASPI, EU, URG, UROY) have current revenue or near-term production paths — they trade more like commodity-leveraged operators than option values. The development-stage names (NNE, LTBR, ISOU) are multi-year option setups where the binary outcome is licensing milestones, design-test data, or resource definition. Mixing the two in roughly 60/40 weighting concentrates the exposure to the structural HALEU + uranium supply story while keeping convex upside on the SMR licensing pathway.

How We Scored

Our model rates every US small-cap stock (market cap <$2B) across eight fundamentals: revenue growth, gross margin, cash runway, debt/equity, P/S ratio, Rule of 40, insider ownership, and 12-month dilution. Sector-adjusted where appropriate. Scores refresh weekly. See methodology or browse all small-cap energy & materials stocks.

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Data as of May 28, 2026. Updated monthly. Past performance does not guarantee future results. Not investment advice.