Few years ago same thing happened to Onix
People bought a lot at the range of $30-35 probably on a margin and a month late were washed away at $20+ (I was one among them).
Another explanation could be PAR invest shorting and accumulating
Also Renaissance (number one share holder now) , Jim specializes on computer generated trades that as he says "others poorly execute". as to me Tang and Renaissance are the worst holders to be in a company with,
Anyway good luck.