Just speculation on my part as I really don't know. But there was a huge short interest . HK has been trending north for a few days on good volume suggesting the shorts were unwinding their positions. It just may be that some were running up against the clock and needed some downward pressure to finish closing out their positions (and preserve profits) incase the earnings beat the street. Today's volume plus the price being off the day's lows suggest the shorts are continuing to cover this morning.