Shares of major neocloud stocks fell on Monday after Elon Musk said that more than 200 companies in the sector could collapse.

Nebius, CoreWeave and Iren all dropped more than 4% in premarket trading, adding pressure to a sector already facing investor concerns about debt-fueled expansion and whether the large AI infrastructure buildout will generate returns.

"As of the past few weeks, debt markets have almost entirely shut off access to money for any company that doesn't have substantial revenue independent of AI data centers," Musk said on a post on X on Sunday.

"That means the 200+ neoclouds are going to see guppy-level death and consolidation. Some will make it through, but not many," he added.

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