The 7.33 million shares currently short for Vertex (short ratio 1.4 days) represent quite a low number of short shares relative to what it has been in the last year or so. There are good reasons for this: Any day now they will be releasing phase I results for Alios nucleotides and possibly announcing multiple phase II combination studies with these nucs. But the really big news will be in several weeks when they release the final results of the kalydeco/VX-809 study and announce the phase III trials for this combination.