Elon Musk said that many neocloud companies face "guppy-level death." Bloomberg/Getty Images

Neocloud companies are sliding even lower.

Shares dropped further on Monday after Elon Musk warned that many of them face "guppy-level death."

CoreWeave and Nebius have both fallen more than 30% over the past month, largely due to growing concerns about the debt they've taken on to build more data centers.

In early premarket trading on Monday, CoreWeave was down another 5%, and Nebius was down 3%, though those losses pared somewhat as the opening bell approached.…