That is a good question. The below is a link that explains stock gaps. There are traders who believe stock gaps have to be filled and if a stock starts moving closing to the gap price you will see many posts stating that. In our case there appeared to be a few MM's wanting to cover lower so they used the gap in the chart for that purpose IMO. There wasn't dilution for awhile now so that wasn't the case for the drop. Then there is dark pool trading which is a real thing that the SEC is looking at. Here is a link about that practice.
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