Critical Mass: Nuclear & Fusion in the Private Secondary Market – SMRs, Startups & Valuations

It was a very choppy week in the equity markets. Markets opened strong on Monday, but chip stocks and other AI-related companies plunged through mid-week over caution about the broader AI trade as well as the Fed keeping rates unchanged. The Fed decision drove bond yields higher, creating increased concern about financing costs for the buildout of data centers. However, markets rebounded strongly on Thursday, with Micron, Microsoft, SanDisk and AMD all rallying; Meta remained down for the week after its weak earnings. Overall, the S&P and Nasdaq ended the week about flat. Our NPM Private Market Tracker*, which shows the average price performance of the 50 largest names in our internal NPM Price data, is up ~63% YTD versus the S&P 500/Nasdaq each up ~8% YTD. (Bloomberg, Wall Street Journal, NPM)

Energy has not historically been a prominent sector for VC investing. It is dominated by fossil fuels, which come with commoditization, the resulting lack of a defensible moat, and significant price volatility – not characteristics highly sought after by venture capitalists. Clean Tech is the closest thing VC has to an energy sector, and it has gone through a couple of booms (and subsequent busts): the first, from 2006–2011, focused on solar and biofuels; the second, from 2020–2022, had a broader climate scope including agriculture, transportation, decarbonization and construction. (Bessemer Venture Partners, 11/10/22)

We believe we are currently in a third upcycle for venture energy investment, namely one focused on nuclear and, to a lesser degree, geothermal energy, as data centers look to secure abundant sources of power. The key difference we see between the current upcycle and previous ones is that the previous Clean Tech booms prioritized technology that reduced emissions and also happened to be abundant and relatively cheap, whereas the current surge in energy investment prioritizes technology that is abundant and cheap and also happens to reduce emissions. Enter, nuclear power.

Nuclear power can be generated by splitting atoms (fission) or combining them (fusion). Nuclear fission technology has existed since WW2, and while nuclear power provides more than half of the electricity in countries such as France and Ukraine and in states such as New Hampshire and South Carolina, it has often had a bad environmental reputation (Chernobyl, Three Mile Island) as well as a checkered financial reputation (nuclear power plants are huge, expensive projects for which construction has often gone over time and over budget). (Science Direct, 11/18/20)

Fission’s reputation and fusion’s technological hurdles have not stopped investors from plowing capital into nuclear companies over the last few years, especially as many of them are coming up with ways to “build better” using small modular reactors (SMRs) and modular construction of larger plants.

Pitchbook data on dispatchable energy (i.e. energy sources that can serve as baseload power rather than intermittent/variable renewable sources) reflects how VC energy investments (seed to late-stage VC rounds) have skewed towards nuclear power over the last couple of years versus hydropower and geothermal earlier this decade. This past week alone, Commonwealth Fusion Systems (a fusion company backed by Google) raised a $1 billion round (Axios, 7/30), and Antares, which develops nuclear microreactors for space and defense, raised a $470 million Series C round. (Pitchbook, 7/28)

Even if we included solar and wind in the analysis, VC funding for solar and wind has been scant in comparison since the climate tech upcycle; capital for solar and wind now focuses more on project-level, PE-type funding rather than venture investments in new technology.

The charts below should hopefully give investors an idea of who’s doing what in nuclear energy on both the private and public side. It’s no surprise that several companies have partnered with hyperscalers such as Google and Amazon, given that unlocking cheap, abundant power would be transformative for their businesses. (Sources: Pitchbook, Yahoo Finance, TechCrunch, Company reports, The Business Journals, Wall Street Journal, Energy.Media)

Fission

Private fission companies are focused primarily on building SMRs or on building traditional nuclear plants more efficiently. The public companies are focused on a range of technologies, and, aside from NuScale Power which went public in 2022, all of the ones we list have gone public in the last ~2 years or have filed to go public.

Fusion

On the fusion side, private companies are working with traditional tokamak designs, magnetic pulse fusion, and also laser-driven fusion. General Fusion is the first fusion company to go public (via a SPAC in July 2026), and it was founded in 2002.

Note: Market caps for publicly traded names fluctuate daily and are shown as of the date noted (research date July 30, 2026); several fission names (NuScale, Standard Nuclear, Deep Fission, Newcleo, Hadron Energy, Terrestrial Energy, X-energy) went public via IPO or SPAC merger in 2022–2026, so figures reflect deal value or a recent trading snapshot rather than a stable market cap. Several private valuations (Blue Energy, Antares, The Nuclear Company, Tokamak Energy, Xcimer, Marvel Fusion, Focused Energy, Inertia Enterprises) were not publicly disclosed and are marked accordingly rather than estimated. Technology groupings reflect each company’s primary publicly stated approach; several (e.g. Radiant, Aalo) could sit in more than one bucket.

Based on our proprietary NPM Price data, the best performers of the large cap names in the private market thus far in 2026 have been:

Based on our proprietary NPM Price data using weighted averages for each sector, the top performing sectors YTD taking into account the top 100 largest names are AI and Machine Learning (99%), Consumer (+83%) and Industrials (+54%).

1. 01
   The 30-year Treasury reached its highest yield since 2007 on concerns that the Fed will have difficulty curbing inflation as it held rates steady. Bloomberg · 7/30
2. 02
   Big tech earnings: Microsoft results showed its AI services are making inroads with customers, and it said it won’t burn cash in the next 12 months, driving shares up for the week; Meta’s earnings were disappointing as higher costs dented profits; Apple’s results failed to impress after Thursday’s close, while Amazon’s were better-received on the heels of strong cloud revenues. The Information; Bloomberg · 7/30
3. 03
   Nvidia will invest $5 billion in Safe Superintelligence, an AI lab co-founded by former OpenAI scientist Ilya Sutskever. It is also reportedly in talks to guarantee ~$250 billion of financing for OpenAI to lease a 10GW data center in Ohio, and said it would invest $1 billion in South Korean internet company Naver. Nvidia’s deals this week reignited concerns around circularity in the AI industry. Pitchbook; StrictlyVC; The Information; Bloomberg · 7/27–7/29
4. 04
   Carlyle and Bain are final bidders for RIA Wealth Enhancement Group at a valuation of $7 billion, while Ares Management is in talks to acquire PE firm Leonard Green and Partners. Pitchbook · 7/28
5. 05
   Amazon is entering the direct-to-device (D2D) communication market after filing a request with the FCC to launch 5,000+ LEO satellites, using spectrum from Globalstar (which it agreed to acquire in April) to complement its existing Leo broadband constellation. Payload · 7/28
6. 06
   Meta is bringing BlackRock in to take over much of the financing for its El Paso, Texas data center campus. The Information · 7/29
7. 07
   The PJM power grid warned that it may start temporarily cutting data centers off the grid during high-demand periods. Bloomberg · 7/27
8. 08
   The Trump administration banned imports of newly released Chinese humanoid and quadruped robots, citing risks of espionage, cyberattacks and supply-chain disruptions. StrictlyVC · 7/30
9. 09
   Situational Awareness sold a chunk of its public equities to Citadel. Bloomberg · 7/30