Talen Energy (TLN) and Amazon (AMZN) shares fell over 2% and 1%, respectively, on Monday. The decline came after the U.S. Federal Energy Regulatory Commission (FERC) denied a request to increase the power supply from TLN’s Susquehanna nuclear plant to AMZN’s data center campus.

Big tech companies need lots of electricity for their data centers, which are processing increasingly complex artificial intelligence applications.

Nuclear-power stocks fell after regulators voted against a deal between Amazon and Talen Energy. The deal would permit a Talen nuclear plant to provide an Amazon data center with extra power. Nuclear stocks have surged this year as AI data centers boost energy demand.

Utility stocks are hurting amid news that the Federal Energy Regulatory Commission (FERC) rejected an amended interconnection service agreement between Amazon.com (AMZN) and Talen Energy (NASDAQ:TLN) at the latter's nuclear power plant.

Talen Energy Corp. and other US power company stocks slumped in pre-market trading Monday following the rejection by the country’s top energy regulator of Talen’s plan to supply a data center.

The proposal would have boosted the amount of electricity coming from the Pennsylvania power plant from 300 megawatts to 480 megawatts.

Talen said it believed FERC had erred and was evaluating its options. The company can still restructure its expanded deal with Amazon, according to Oppenheimer analysts.