Transfers are recognised at the date of the event or change in circumstances that caused the transfer. With the introduction of ASU No. 2011-4 the Group has reassessed the observability of fair value inputs as of 1 January 2012. Yield curves for instruments with maturities above 20 years were deemed observable and related positions were therefore reclassified to level 2. The inputs of one level 2 position were assessed to be unobservable, the respective assets and liabilities were therefore shifted to level 3.