By Noele IllienAnnouncing the biggest banking deal since the 2008 global financial crisis, UBS Chief Executive Sergio Ermotti and Chairman Colm Kelleher said it would create challenges but also "many opportunities" for clients, employees, shareholders, and Switzerland. What's more, the disappearance of Credit Suisse's investment bank, which UBS has said it will seek to cut back significantly, marks yet another retreat of a European lender from securities trading, which is now largely dominated by U. They also warn that uncertainty inevitably caused by a takeover of such scale can leave UBS struggling to retain staff and customers and that it remained an open question whether the deal can deliver value for shareholders in the long run