Credit risk rating at large U.S. banks

Large banks use internally developed credit rating systems to differentiate the riskiness of their commercial loans. Internal ratings are an essential ingredient of effective credit risk management for such banks, whose commercial borrowers may number in the tens of thousands. This article describes these rating systems, how their design varies across institutions, and how they are used in risk management. The article also outlines conceptual and practical difficulties currently faced by banks in achieving accurate and consistent ratings and describes ways in which some institutions have attempted to deal with these difficulties. This article is based on a detailed review of policy documents and internal management reports from the fifty largest U.S. bank holding companies and interviews by the authors at a selection of these institutions.