Short Sellers Reap $6 Billion as AI Data Center Stocks Slide on Debt Concerns

Short sellers betting against five AI data center operators have booked about $6 billion in paper profits since October, as investors question whether debt-fueled buildouts can be sustained by future cash flow. CoreWeave (CRWV), IREN (IREN), Nebius (NBIS), Applied Digital (APLD) and Core Scientific (CORZ) have led the retreat, according to data from analytics firm ORTEX. Short interest across the five neoclouds now stands at roughly 20% to 26% of free float, with total shares sold short valued at about $17 billion. CoreWeave has fallen nearly 30% this month, delivering short sellers some $1.7 billion; its short interest rose to 23.7% from 19.6% in early October. Nebius carries 20% short interest, up from 15.4% at the start of the year, with October gains of about $2.94 billion, though shorts remain down about $3.33 billion year-to-date. Unlike Amazon, Microsoft and Google, these operators primarily sell GPU compute capacity and have funded rapid expansion with heavy borrowing. Market attention has shifted from GPU procurement and revenue growth to financing costs, leverage and payback timelines.