As of 2015, the stock market operating hours are regularly from 9:30 a.m. to 4 p.m, Eastern time, according to Scottrade. The specific stock market working hours depend on the trading activity and the day of the year.
Premarket hours on a typical market day precede regular market hours and start at 6 a.m. Eastern time, notes Scottrade. Investors can trade during these extended trading hours on Nasdaq’s national market and listed securities market. After-market hours begin two minutes after the regular day ends and finish at 8 p.m. Eastern time. Half-market days shorten both regular and after-market hours, while no trading hours are available during nine holidays, including Good Friday, Thanksgiving Day and Christmas Day.