Nuclear Startups Raised Over $6 Billion in 2026 — a Record

Investors have poured more than $6 billion into nuclear power startups so far in 2026, an all-time high for the sector, according to Crunchbase data. The private-market boom, fueled by expectations of surging energy demand from artificial intelligence, stands in sharp contrast to what is happening on public exchanges, where newly listed nuclear companies are trading far below their peaks.

Round counts are also holding at historically high levels, per Crunchbase. This year's total already exceeds every comparable period, including last year — the prior record-setter.

Where did the money go?

Much of the 2026 funding concentrated in a handful of heavily financed companies. Two startups alone secured $1 billion each.

• Commonwealth Fusion Systems, based in Massachusetts, raised $1 billion in a July equity financing. The company is developing what it describes as the "world's first commercially-relevant net energy fusion machine."
• Valar Atomics, a developer of grid-independent nuclear reactors, picked up $1 billion across two Series B equity tranches.

Crunchbase charted 11 of the largest nuclear-sector funding rounds of the year, with the two billion-dollar deals at the top.

What happened to the nuclear IPOs?

The past six months brought at least three nuclear-related IPOs with initial valuations above $1 billion. Most now trade well below their former highs.

The largest debut came in April from X-energy. The Rockville, Maryland-based developer of small modular nuclear reactors and fuel engineering technology hit a $12 billion valuation in initial trading. Shares have since shed about half their value.

Two summer offerings followed:

• Standard Nuclear, an Oak Ridge, Tennessee-based developer of advanced nuclear fuels, went public and now trades well below its peak.
• Deep Fission, a Berkeley, California-based modular reactor startup, also debuted and sits well below former highs.

Oklo, the Sam Altman-backed nuclear fission company that kicked off the nuclear IPO boomlet with its 2024 market debut via SPAC, is seeing weakening demand too. Its shares are down about two-thirds from a high point roughly a year ago.

Why are public and private markets diverging?

It remains unclear whether the share-price setbacks reflect diminished optimism about the feasibility of nuclear startup ambitions, or simply a judgment that valuations warranted a cutback. In the U.S., public backlash against massive data center buildouts is also weighing on the energy upstarts looking to power them and has contributed to investor caution.

Next-generation nuclear power also remains early-stage. The U.S. Energy Information Administration reports that very little nuclear capacity has been built over the past few decades, citing high capital costs and lengthy licensing and approval processes as limiting factors. Scalable fusion, meanwhile, has yet to come online.

What comes next?

A broad assortment of nuclear projects are moving forward regardless of stock performance. Multiple companies working on small modular reactors and microreactors have projects underway in Texas, Idaho, Utah and Tennessee, per the EIA, and a longer list of projects sits in later-stage planning.

Hefty fundraising in recent months — from both IPOs and venture rounds — has given startups the runway to keep forging ahead, even as public-market investors reassess what nuclear shares are worth.