The two major US exchanges are the New York Stock Exchange (NYSE) and the Nasdaq. They are both based in New York and are open Monday through Friday from 9:30 a.m. to 4 p.m. EDT or EST depending on whether day light saving is in place or not.
The frequency of trading is usually slow during the middle of the day. Trading frequency is higher around the opening hours and closing hours. The duration of the trading session is total of 6 hours and 30 minutes. The remaining hours of the day are spent by traders researching and analyzing the market information before deciding to make a trade