I read an interesting article that said all market gains have occurred after hours since 1993. If you exclude after hours gains, the market is actually down. I find this completely fascinating. With that in mind it seems one could take advantage of price action in these two time windows. Something basic that comes to mind are opening bull call spreads at market close and closing at the open. That would help capture the overnight gains and protect from a major overnight selloff. On the flipside, it seems a theta capturing strategy that is opened at the open and closed at the closed would be optimal, since the market has basically been a sideways market for the last 20 years when looking at just open hours. Does anyone here already trade this phenomena or has studied this out in more detail?