During regular trading hours, the stock market is open, allowing investors to buy and sell securities. After-hours trading occurs outside normal market hours and can have lower liquidity and higher volatility. Regular trading takes place between 9:30 a.m. to 4:00 p.m. After-hours trading happens before the market opens or after it closes. Price changes in after-hours trading may not reflect the next day's opening price. In after-hours trading, news can greatly impact stock prices since trading volume is lower. Unlike regular trading, after-hours trading can have wider bid-ask spreads and limited participation from investors. Monitoring both regular and after-hours trading is crucial for informed decision-making.