Shares of n𒊎uclear power providers tumbled on Monday as markets reacted to the success of a Chinese startup’s AI model that challenges the performance of the most advanced American models while us🅺ing less computing power.

Vistra (VST) was the worst-performing stock in the S&P 500 as its shares tumbled nearly 30%. Competitor Constellation Energy Corp. (CEG) was down more than 20%, making it the fourth-worst performing stock in the index on 澳洲幸运5官方开奖结果体彩网:a rough day for the S&P 500 and Nasdaq Composite.

Both companies' shares have soared in the past year amid an AI-driven surge in electricity demand. Tech giants like Microsoft (MSFT) and Amazon.com (AMZN), desperate to develop the most powerful AI models, have turned to nuclear as a carbon-free source of power for their data centers. Microsoft last year 澳洲幸运5官方开奖结果体彩网:struck a deal with Constellation to restart one generator at Pennsylvania’s notorious Three Mile Island nuclear facility. And Amazon 澳洲幸运5官方开奖结果体彩网:has invested in the development of🌼 small mꦇodular reactors to power its data centers. 

The popularity of Chinese startup 澳洲幸运5官方🧸开奖结果体彩网:DeepSeek’s newest open-source AI model has 澳洲幸运5官方开奖结果体彩网:sparked concern on Wall Street that cutting-edge AI may not need as much computing power as expected. DeepSeek’s AI model is estimated to run at just a tenth of the cost of leading U.S. models, like Meta’s (META) Llama.

Jefferies analysts on Monday wrote that DeepSeek’s success could force the American AI industry to “refocus on efficiency and ROI, meaning lower demand for computing power as of 2026.” That, they said, could put U.S. executives “under more pressure to justify raising AI capex,” raising the prospect that surging electricity demand could abruptly plateau. 

Those doubts spooked investors in utilities sꦗtocks like Vistra and Constellation Energy, which have 🧔both more than doubled in value in the past 12 months.

Update: This article has been updatꦗed since it was first published to reflect the latest share-price data.