I notice on the cme website the trading hours are MON-THURS: 5:00 pm -3:15 pm & 3:30 pm - 4:30 pm (Daily maintenance shutdown 4:30 p.m.-5:00 p.m.) Just wondering since there is a maintenance shut down for 30 minutes and market closing at 3:15pm-3:30pm, how is the daily high and low calculated? I know for stocks the daily high and low is calculated from the time the market opens and closes which is 9:30am-4:00pm EST, but for the futures there seems to be a 15 minute break and a 30 minutes maintenance shut down.