Having traded NG for several companies over the years and I believe that crude would follow suit, large volume of k's went through during open pit hours for a variety of reasons. My experience was :1.)This is or at least it was when the decision makers were in and when they felt more comfortable make large trades (prod/gen hedges). 2.) More traders and others back office personal are in. I mean we worked 7a-6p but we were there to make trades whether spec or hedge, and we mostly cleared through otc and floor. 3.) The floor is the market or at least it historically has been. Times are changing but at least for a little longer the floor rules
Has nobody considered the effect that day margin has? Margin requirements are often 10-25% of the ETH requirement during RTH hours. So if one is not adverse to leverage, or trading from a smaller account, it makes much more sense to trade during RTH/pit hours. It's also when most of the key economic reports come out, with the exception of the NFP report tomorrow. I still don't know why they haven't moved that one to RTH. I mean hell they just moved the USDA report to 12:30 EST instead of 8:30 EST, so now you can use day margin around the report as well. The volume increase last month when they did that was huge, and the only real difference that I can see (aside from us West Coast traders not having to get up so damn early) is that intraday margin was now in effect.
This doesnt effect the traders that create the volume the OP is asking about. FCM's provide customers position limits, those limits can be used at any time, day or night.
The actual margin necessitate by the exchange never changes. Brokers set intraday margin lower, I assume based on whatever their FCM calculates is acceptable via their risk management. I won't pretend to know how the FCM makes these decisions.
I see what you're saying. Yeah I hadn't considered that. And I suppose not every broker does $400 or whatever on the ES intraday. I for one would welcome more volume and volatility during the ETH -- not being a morning person makes being a trader on the West Coast unpleasant at times. I've thought about moving to NY or FL or even Chicago just to be able to sleep in later.
It is not just the oil futures but all futures have more volume during regular hours because USA is where the major "Futures" betting takes place. USA sleeps at night and work only during regular market hours. Also you are looking at the "West Texas crude oil" contract which is traded more in US than in rest of the world (Brent Crude).