The majority of trading activity in the U.S. stock market occurs during regular trading hours, from 9:30 a.m. EST until 4:00 p.m. EST. However, most major brokerage firms facilitate after-hours trading for retail and institutional investors.
After-hours trading takes place from 4:00 p.m. EST to 8:00 p.m. EST.
Trading outside of regular hours is handled through electronic communication networks, or ECNs. ECNs allow traders to participate directly with one another while the exchanges are closed.
After-hours trading carries more risk, as less volume creates illiquid markets and wider bid-ask spreads and potential stock gaps, but it also allows investors to take advantage of unique opportunities after the market closes.
After-hours trading activity is typically greatest around events such as corporate earnings announcements.
Extended hours overnight trading is available through some brokerage firms in major ETFs for near-continuous trading.