Costco stock jumps after December sales climb — what matters before Friday’s openNEW YORK
Jan 9, 2026, 05:17 EST — Premarket Costco Wholesale Corp’s (COST.O) shares rose 3.7% on Thursday to $915.31 after the warehouse retailer reported December sales results. Yahoo Finance+1 The monthly report matters because it lands between earnings and can quickly reset expectations for traffic, pricing and renewal-driven demand. Costco’s numbers are also watched as a bellwether for big-box retailers including Walmart and Target, and for warehouse rival BJ’s Wholesale Club. The move shows how tightly investors are trading the story right now. Costco has been priced for steady growth, so any sign that sales are bending — up or down