That is not necessarily a good thing, that the short position is SO heavy and SO prevalent that there are no shares left to short.
The positive spin is that all the damage is built in and all they can do is push share prices higher. But this can go a lot lower before ey have to cover. A strong launch of Belviq would create quite a squeeze.
Shorts being out of ammo on official launch day could not possibly be interpreted as a good thing for the shorts. They now must depend upon longs to sell for any help.
What long sells at product launch?
We will see the MM's pass shares around in an attempt to reign it back in. But that is also a losing battle since the loss is taken my the MM as institutions are willing to step in and pick off some shares as that game is played.
Having no shares to short is not just positive spin. It is just plain positive. Having about 60 million shares on the short side of the trade is not a negative in this case. They placed their bets and many of them never thought this day would arrive.