[We examine whether "rating shopping" or "rating catering" is a more accurate characterization of rating agency interactions regarding collateralized debt obligations (CDOs). Although investors paid a premium for dual ratings, AAA CDO tranches rated by both Moody's and S&P defaulted more frequently than tranches rated by only one of them, which is inconsistent with pure rating shopping. Rating agencies made upward adjustments beyond their model when their competitor had more lenient assumptions. Finally, consistent with rating catering, S&P's and Moody's adjustments and disagreements at security issuance were reflected in subsequent rating downgrades, suggesting that adjustments were harmful.]

We examine whether “rating shopping” or “rating catering” is a more accurate characterization of rating agency interactions regarding collateralized debt obligations (CDOs). Although investors paid a premium for dual ratings, AAA CDO tranches rated by both Moody's and S&P defaulted more frequently than tranches rated by only one of them, which is inconsistent with pure rating shopping. Rating agencies made upward adjustments beyond their model when their competitor had more lenient assumptions. Finally, consistent with rating catering, S&P's and Moody's adjustments and disagreements at security issuance were reflected in subsequent rating downgrades, suggesting that adjustments were harmful.