Fission SMRs, fusion programs, and the nuclear supply chain returning to venture scale.
Components that cannot be computed are dropped and the weights renormalize — never faked to neutral.
Undisclosed amounts count as zero capital; deals still count.
| # | Company | Valuation | Secondary vs Round | Last Round |
|---|---|---|---|---|
| 1 | Helsing | $18B as of 2026-Q3 | no mark | 2026-07-13 |
| 2 | Helion Energy | $16B as of 2026-06 | +55.5% | 2026-06-01 |
| 3 | Valar Atomics | $6.0B as of 2026-Q3 | no mark | 2026-08-01 |
| 4 | Commonwealth Fusion Systems | $5.0B as of 2025-Q4 | no mark | 2025-08-01 |
| 5 | Black Forest Labs | $3.3B as of 2025-Q4 | no mark | 2025-12-01 |
| 6 | TerraPower | $2.5B as of 2022-Q3 | no mark | 2022-08-01 |
| 7 | TAE Technologies | $2.5B as of 2025-Q2 | no mark | 2025-06-01 |
| 8 | Radiant | $1.8B as of 2025-Q4 | +11.7% | 2025-12-15 |
| 9 | KoBold Metals | $1.7B as of 2026-01 | +2.2% | 2025-01 |
| 10 | Zap Energy | $1.1B as of 2024-Q3 | -77.7% | 2024-07-30 |
| 11 | Stability AI | $1.0B as of 2024-Q2 | no mark | 2024-06-15 |
| 12 | Xaira Therapeutics | $1.0B as of 2024-Q2 | no mark | 2024-04-23 |
Methodology. Emerging Spaces groups the tracked private-company roster into curated thematic spaces and scores each space's momentum 0–100 from four disclosed-data components: trailing-90-day capital vs the prior 90 days (40%), deal-count acceleration on the same windows (25%), news activity per tracked company over 30 days (20%), and the median secondary-market premium to last round across the space's marked names (15%). Components that cannot be computed are dropped and the weights renormalize — the basis is disclosed per space. Quarterly trends derive from dated, disclosed rounds; undisclosed amounts count as zero capital. An attention map of disclosed activity — not a prediction, not investment advice.