COST Premarket & After Hours Quote
Costco Wholesale (COST) Stock Extended Hours Trading activity trade start in the Premarket (4:00-9:30 a.m. ET) and the After Hours Market (4:00-8:00 p.m. ET). Extended hours trading is trading conducted by electronic networks either before or after the trading day of a stock exchange, i.e., premarket trading or after-hours trading. It tends to be limited in volume than regular trading hours when the exchange is open.