ESG and sustainable funds increase nuclear stocks exposure by 95%

The EU did something quietly consequential last year. Its updated guidance excluded nuclear arms from the definition of controversial weapons, a classification that had previously made nuclear-adjacent holdings radioactive for ESG portfolio managers. Fund managers who once had to screen out nuclear exposure entirely now have regulatory cover to hold it.

ESG and sustainable funds have increased their exposure to nuclear stocks by 95% since June 2025, according to Bloomberg Intelligence data presented on Bloomberg ETF IQ. A Jefferies survey conducted in May 2026 found that approximately two-thirds of fund managers now allow some level of nuclear exposure in their portfolios. That number includes 34% who permit holdings even in nuclear weapons-related companies.

Nuclear power produces no direct carbon emissions during operation. It provides reliable baseload electricity that wind and solar, on their own, still cannot consistently deliver.

Nuclear’s crypto connection

Nuclear power has quietly become a meaningful part of the energy mix for Bitcoin mining operations. According to data from the Cambridge Centre for Alternative Finance, nuclear accounted for roughly 10% of the sustainable energy sources powering Bitcoin mining activity.

Talen Energy partnered with TeraWulf specifically to build zero-carbon mining infrastructure. Energy Harbor struck a similar arrangement with Standard Power. Both partnerships were structured around using nuclear-generated electricity as the primary power source.

What this means for investors

For crypto investors, the nuclear-mining connection creates an indirect but real linkage between ESG capital flows and mining economics. Miners with established nuclear power agreements are now better positioned to attract institutional capital from funds that require low-carbon credentials in their portfolio companies.

The risk worth flagging: ESG taxonomy is not static. The EU guidance that opened the door to nuclear investment could be revisited, tightened, or challenged by member states with different energy politics. Germany’s long-standing hostility to nuclear is the obvious counterexample.

What to watch is how quickly ESG fund managers formalize their nuclear policies rather than operating under informal tolerance. A Jefferies survey capturing two-thirds acceptance is one data point. Actual fund mandates being rewritten to explicitly permit nuclear is a harder, more durable signal.

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