That is not after hours trading like you see in the big boards. There is only "t-trades" at closing which are trades that were in the process of going through when the market closed, or MM's putting through their last trade. Then you see a very few MM trades go through pre-market. But that isn't retail guys like us putting trades through before the bell, as far as I know (which isn't a lot). I often wish I could put through a pre-market trade :-) But anyway, in reply to the original observation, the MM's have held their bid / ask positions. I often see the same thing with my Scottrade account where they suddenly show a wide spread on bid and ask after the bell. Level 2 shows the real MM positions.
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