Most major exchanges trade from 9:30 am to 4 pm Eastern Standard Time, but you’re not limited to selling stock between those hours. The pre-market is open from 8 am to 9:30 am, and the after-hours market trades from 4:30 pm until 8 pm.Shares trade at agreed-upon prices in the pre- and after-hours markets, just like the regular market. But there is typically less liquidity, more volatility, and lower volume than the regular market. This can affect prices, so using limit orders is important. Price changes in the after-hours market have the same effect as they do during regular hours. A stock may fall from $10 to $9 during the regular session, but if it climbs $1.50 during the after-hours, the owner has a 50-cent gain. Stocks don’t always open at the price they closed at in the previous session. If a stock’s price grows substantially in the after-hours market due to a rumor of higher sales, many investors may be waiting to sell as soon as the regular market opens. Increased selling pressure will drive the stock down.