As speculated earlier by IP pharma doc that behind Ranbaxy sell out Lipitor may be the one of the reason, now forbes has came out with an article ( Link to forbes news) that Pfizer is interested in remaining shares of Ranbaxy. The purpose of this interset is due to billion dollar revenue generator "Atorvastatin" (Lipitor and caudet) First to file exclusivity. After the expiry of Pfizer's patent on Atorvastatin in March 2010, Ranbaxy can severely dent the sale of Lipitor and Caudet and to stop generic competition for 6 months will result in huge financial benefit to pfizer.