A glance at the MNTA institutional ownership (81%) goes to 91% when you add in NVS and the increase in Discovery (post 6/30). Of course there could have been others selling.
The table below shows all shareholders who filed their MNTA holdings on SEC Form 13-G in Feb 2011 (or later); the holdings are updated each for filings on Form 13F-HR (except Novartis) and are accurate as of 6/30/11. The percentages in the table are based on 53.3M diluted shares (#msg-65636329) and do not concur with the percentages on Form 13-G, which use a different formula. (For insider holdings, see #msg-66636158.)