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.

And seeing as Oklo stock has more than doubled over the last 12 months, while Nano Nuclear has nearly quadrupled, and NuScale almost sextupled, it probably makes investors a bit more eager to take profits today, rather than see how this FERC situation eventually resolves itself.