1. What time of day to do enter your option trades? I have been wondering whether it really makes a difference. I have looked at the open (9:30AM). I have looked at mainly 10:00AM, 10:30AM, 11:00 AM, lunchtime (12-1PM), 4:00PM, and since I trade ES FOP, the time between 4-4:15 (All times EST). My option strategy is a combo of long and short options. 2. What day of the week? In my case, it doesn't matter since I want trades to be placed on high volatility days. 3. What type of person/entity trades during each of the above time frames? In other words, are retail traders mainly trading at the opening? When do the hedge funds trade? Institutional/mutual fund managers trade? Lastly, since the NYSE/AMEX/NASDAQ close at 4:00PM, who trades between 4-4:15PM? These are questions I have pondered for a while, and just never thought to ask.