Moody's endorses the Basel Committee's proposal to use banks' internal risk assessments to refine the Basel Accord's risk weights on bank assets and commitments. External risk assessments, such as Moody's credit ratings, will likely play a supporting role as direct inputs into banks' internal rating systems and as tools for benchmarking and validating those systems. However, the widespread use of ratings in regulation threatens to undermine the quality of credit over time by increasing rating shopping, decreasing rating agency independence, and reducing incentives to innovate and improve the quality of ratings. This paper discusses how bank regulators can use external ratings in ways that mitigate the adverse incentives created by the resulting regulatory demand for rating agency services.

Many regulations use private sector credit ratings to determine investment prohibitions and capital requirements for institutional portfolio investments. These regulations implicitly assume that different agencies have equivalent rating scales, despite the fact that some agencies assign systematically higher ratings than others. We assess the appropriateness of these regulatory practices by testing whether observed rating differences reflect different rating scales or simply result from sample selection bias. Our analysis reveals only limited evidence of selection bias. We also ask what types of firms of firms are most likely to seek ratings from the agencies with higher rating scales. Our analysis uncovers no evidence that firms seek ratings from these agencies to clear specific regulatory hurdles or to reduce ex ante uncertainty about default risk.

We use two alternative matched-set methodologies to examine for differences in loan and bond default rates among US non-financial corporate issuers. Under both methodologies, the data indicate that loan default rates are roughly 20% lower than the bond default rates due to issuers that default on their bonds but avoid bankruptcy and avoid defaulting on their loans. For a small number of European issuers, the data suggest a similar reduction in loan default rates relative to bond default rates. However, the European results differ qualitatively from the US results, due likely to differences in US and European bankruptcy regimes, as well as the larger role of bank debt on most European issuers’ balance sheets. These results have important implications for investors, bank supervisors, and rating agencies that assess the relative expected credit losses on loans versus bonds.