After-hours trading refers to the buying and selling of securities after the regular trading session has ended. On US exchanges, after-hours trading typically runs from 4:00 PM to 8:00 PM Eastern Time. Like pre-market trading, after-hours sessions have lower volume and wider spreads than regular hours. This period is significant because many companies choose to release quarterly earnings after the market close, leading to substantial price movements in after-hours trading. Institutional investors and active traders use this session to react to breaking news without waiting for the next regular session. After-hours trading uses Electronic Communication Networks (ECNs) rather than the traditional exchange mechanisms, and typically only limit orders are available. The after-hours price often sets the tone for the next trading day's pre-market and opening price, making it important for overnight position management.