Quote from nevadan:
Great question Tide31.
Regarding the liquidation idea, it seems like it would be better to be a little more subtle about a liquidation than the massive pulse that seems to be simultaneous across the broader market. Selling into strength makes sense but all at once? Also, the market recovers rather quickly from such a large volume of selling. The chart is from Friday and is built from one second data. Time is PDT. As you can see the character of the market changed at 11:00. The tick started making wild swings and the breadth, brokers/dealers, and net volume were pretty much in lockstep. The black boxes were in control, but who's boxes and why? Beats me but it seems pretty clear that it is massive and unidirectional, both up and down.