Never buy after hours or pre market. Every once in a while you can get a better fill if you do that but 95% of the time you will get burned. Never do it. Example, Neddham initiated OSTK after hours yesterday with a conviction buy and a $150 target. The stock closed at 86 and after hours was trading at $89.50. In other words, shorts were covering and suckers were buying. What happened ? The futures got hit hard this morning and OSTK opened near $87. I bought a small position at 87.10 and sold just under 88. It did go to 90 but those that bought at $89 after hours more than likely panicked and sold the opening bid. The only reason I bought at the open was because I knew shorts were given a gift with the futures getting hit. Had the futures been up, OSTK would probably of opened near $89. Buying the open is something I also try to avoid.
A good rule of thumb. I follow it too. Someone buys stocks before the market opens, and after the opening there will be a gap. So you can get a margin call. Somehow, right after the market opened, I bought an ATVI share, because my technical analysis showed that I needed to buy. I lost $ 300 in a few seconds. The action did go in the right direction. But then.
%% NEVER is a long time\ i see your points. Buying the open or selling open with a resting order can work well .Premarket tends to not have much good volume. POST market \hardly ever see anything interesting on spy or QQQQ; soemthing post market may be noteworthy in an old WSJ/LOL SDS......open was to hi to buy for me today; post market would be better or close to reg close area is better for swing most likely................................................................................