Models for Moody’s Bank Ratings

Abstract

The paper presents an econometric study of the two bank ratings assigned by Moody's Investors Service. According to Moody’s methodology, foreign-currency long-term deposit ratings are assigned on the basis of Bank Finan-cial Strength Ratings (BFSR), taking into account “external bank support factors” (joint-default analysis, JDA). Models for the (unobserved) external support are presented, and we find that models based solely on public infor-mation can approximate the ratings reasonably well. It appears that the ob-served rating degradation can be explained by the growth of the banking sys-tem as a whole. Moody’s has a special approach for banks in developing countries in general and for Russia in particular. The models help reveal the factors that are important for external bank support.