Funding to nuclear power-focused startups hit an all-time high this year, fueled by expectations of surging energy demand around artificial intelligence. Optimism around IPO prospects, however, has taken a hit recently amid weakening public market enthusiasm for the space.
So far in 2026, investors have poured more than $6 billion into companies focused on developing both fission and fusion nuclear energy technology and infrastructure, per Crunchbase data. That’s far ahead of any comparable period, including last year, the prior record-setter. Round counts are also holding up at historically high levels, as charted below.
Biggest rounds
Much of this year’s funding went to a few heavily financed nuclear startups.
This included two billion-dollar recipients. Massachusetts-based Commonwealth Fusion Systems, which is developing what it describes as the “world’s first commercially-relevant net energy fusion machine,” secured $1 billion in a July equity financing. Meanwhile, Valar Atomics, a developer of grid-independent nuclear reactors, picked up $1 billion across two Series B equity tranches.
For a bigger-picture view, below we charted 11 of the largest funding rounds for the nuclear sector this year.
IPOs were going strong too
Recent quarters have also been pretty strong for IPOs tied to nuclear power. In the past six months alone, at least three companies in the space went public at initial valuations above $1 billion. Most, however, are now far below their prior highs.
The largest debut came in April from Rockville, Maryland-based X-energy, a developer of small modular nuclear reactors and fuel engineering technology, which hit a $12 billion valuation in initial trading. Shares have subsequently shed about half their value.
The next-biggest offerings were summer debuts from Oak Ridge, Tennessee-based Standard Nuclear, a developer of advanced nuclear fuels, and Berkeley, California-based Deep Fission, a modular reactor startup. Shares of both are trading well below former peaks.
Oklo, the Sam Altman-backed nuclear fission company that to some extent kicked off the nuclear IPO boomlet with its 2024 market debut via SPAC, is also seeing weakening demand. Its shares are down about two-thirds from a high point about a year ago.
Optimism matters
It’s unclear to what extent recent share price setbacks reflect diminished optimism about the feasibility of nuclear startup ambitions or more a sense that valuations warranted a cutback. In the U.S., public backlash against massive data center buildouts also affects the energy upstarts looking to power them and has contributed to investor caution.
Moreover, next-generation nuclear power is still in its early innings. Over the past few decades, the U.S. Energy Information Administration reports, very little nuclear capacity has been built, citing high capital costs and lengthy licensing and approval processes as limiting factors. Scalable fusion, meanwhile, has yet to come online.
Still, a broad assortment of nuclear projects are moving forward. Multiple companies working on small modular reactors and microreactors have projects underway in Texas, Idaho, Utah and Tennessee, per the EIA. A longer list of projects is in the later-stage planning phase. And, hefty fundraising in recent months from both IPOs and venture rounds has given startups the runway to keep forging ahead.
Related Crunchbase queries:
- Nuclear Energy-Related Startup Funding, 2026
- Nuclear IPOs, 2026
- Largest 2026 Nuclear Fusion- And Fission-Related Funding Recipients
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Illustration: Dom Guzman
