If you trade U.S. stock index futures and you’ve had the sneaking suspicion lately that a lot of the action is over by the time you’ve finished your morning coffee, it’s not entirely your imagination.

Although the majority of price movement still occurs during the regular day session (8:30 a.m.-3:15 p.m. CT), E-Mini S&P 500 futures (ES) data analysis shows the primary overnight session (5 p.m-8:30 a.m. CT next day) has been accounting for more of the total (24- hour) daily range.