Alta has to be just about done dumping. They had so many shares and the volume indicates a slow selling process. They no longer come up as a 5% holder in Corcept. My guess is that they're just about done. It looks like Longitude Capital Partners is really boosting its position. Sutter Hill also owns a huge block. This company is so tightly held that it's going to rocket on great news which will come IMO. I'm just accumulating weekly at this point. It's pretty clear that someone is grabbing the shares as Alta dumps. They have been liquidating for a long time and must be done at this point...if not, then I'm guessing that they're under a million shares.
The only really good thing I see in this is that they are not just dumping the shares which of course would hurt both Alta and oridinary investors. The demand seems to be there to absorb the selling. My guess is that Alta also want to catch some upside once the NDA is filed (if they can hold out that long). In venture capital land there is little that can be done to extend the life of a fund once it has expired. I'm guessing that is the reason for the liquidation. You can extend the life of funds through internal transfers, but I'm not sure how common that is once a company is public.