The wealth of data now available allows us to estimate which quantitative indicators are weighed most heavily in the determination of ratings, to evaluate the predictive power of ratings in explaining a cross-section of sovereign bond yields, and to measure whether rating announcements directly affect market yields on the day of the announcement. Our investigation suggests that, to a large extent, Moody’s and Standard and Poor’s rating assignments can be explained by a small number of well-defined criteria, which the two agencies appear to weigh similarly. We also find that the market—as gauged by sovereign debt yields—broadly shares the relative rankings of sovereign credit risks made by the two rating agencies. In addition, credit.
