In business, the trading day is the time span that a particular stock exchange is open. For example, the New York Stock Exchange is, as of 2015, open from 9:30 AM Eastern Time to 4:00 PM Eastern Time. Trading days are usually Monday to Friday. When a trading day ends, all share trading ends and is frozen in time until the next trading day begins. There are several other special circumstances which would lead to a shortened trading day, or no trading day at all, such as on holidays.
The NYSE and NASDAQ average about 252 trading days a year. This is from 365.25(days on average per year) * 5/7(proportion work days per week) = 260.89 - 9(holidays) = 251.89 ~ 252. The holidays are New Year's Day, Martin Luther King Jr. Day, Washington's Birthday, Good Friday, Memorial Day, Independence Day, Labor Day, Thanksgiving Day, Christmas Day. Up to three trading days (the days surrounding Independence Day, Thanksgiving, and Christmas Day) are shortened, i.e. the exchanges are open from 9:30AM-1:00PM, depending on where they fall in the calendar year.
Trading Days for 2016
There are exactly 252 trading days in 2016. January has the fewest number (19), and August the most (23), with an average of 21 per month, or 63 per quarter.
Out of a possible 366 days, 105 days are weekend days (Saturday and Sunday) when the stock exchanges are closed. Eight of the 9 holidays which close the exchanges fall on weekdays, with Christmas being observed on Monday, December 26. There is one shortened trading session on Friday, November 25, the day following Thanksgiving Day.
Trading Days for 2017
There are exactly 251 trading days in 2017. February and April have the fewest (19), and March and August the most (23), with an average of 20.9 per month, or 62.8 per quarter.
Out of a possible 365 days, 105 days are weekend days (Saturday and Sunday) when the stock exchanges are closed. Eight of the 9 holidays which close the exchanges fall on weekdays, with New Year's Day being observed on Monday, January 2. There are two shortened trading sessions: on Monday, July 3, the day before Independence Day, and on Friday, November 24, the day following Thanksgiving Day.