Don't miss this other obvious point, that volume was extremely low on a down day for the market. Shorts push the stock don and hit stops to try to use momentum to push it lower. The problem is that in order to do this they have to short more shares and after doing so all that they accomplished was to get rid of more weak holders of this stock and dig their hole deeper for themselves. To cover their positions, shorts now have less shares available to them to do it and probably a larger short position than when they started. Look for there to be more shares short when short interest is announced.