I don't know if shorters are that big, of 312mil on offer for shorting, only 8.8 mil have been used, that is 0.28 or 2.8% (this is as of 5pm yesterday.
So what I am getting at is that the volume is small compared to available shares, therefore this is some fund dropping thier holding- for it to have been so relentless, also they would have to have held for some time to be getting out at a profit.
my 2c worth
steve