The rating selection is based on the worst external bond rating  (either Moody's or S&P). If no external bond rating exists, the worst external issuer rating  will be used (either Moody's or S&P). In the absence of an external bond and external issuer rating (by either Moody's or S & P), the internal rating of the issuer/borrower will be selected. If neither an external nor internal rating exists the exposure will be rated by using an “assumed rating” – assumed ratings are rating estimates issued by the bank’s credit risk analysts. Assumed Ratings are created by using a rating tool not complying  with Basel II rules.