STOCK EXCHANGES & MARKET HOURS
Plain English
The two biggest US stock exchanges are the NYSE and NASDAQ. Regular trading hours are 9:30 AM to 4:00 PM Eastern, Monday through Friday. Pre-market and after-hours trading also exist but with less liquidity.
Going deeper
The New York Stock Exchange (NYSE) is the world's largest stock exchange by market capitalization. NASDAQ is the second largest and is known for technology companies. Regular Trading Hours (RTH) run from 9:30 AM to 4:00 PM ET. Pre-market trading starts as early as 4:00 AM ET, and after-hours trading extends to 8:00 PM ET, but these extended sessions have lower volume, wider spreads, and potentially more volatile price action. Markets are closed on weekends and designated holidays. Understanding market hours is important for timing orders and managing overnight risk.
Examples
After-Hours Earnings
Apple reports earnings at 4:30 PM ET (after the close). In after-hours trading, the stock jumps $8 on great results. When the market opens the next morning at 9:30 AM, the stock opens at the higher price — you missed the move if you waited.
Pre-Market Gap
Overnight, bad economic data comes from Europe. US futures drop sharply. When the market opens at 9:30 AM, stocks gap down 2% from yesterday's close. Your stop-loss at $48 on a $50 stock executes at $47 because of the gap.