COST ▼ -1.9% - Costco Wholesale Corporation $COST - Costco Wholesale Corporation Reports August Sales Results Costco Wholesale Corporation's stock declined 1.9% today following the company's release of August sales results. Without access to the specific figures in the report, the sell-off suggests investors reacted negatively to the metrics disclosed, though the exact drivers of the decline are not detailed in the headline alone. 02-SEP-2026 04:15 PM ET