Empirical Analysis of Credit Ratings Inflation as a Game of Incomplete Information

Abstract

This paper models competition among credit rating agencies as an auction. Equilibrium ratings give a distorted representation of agencies' true assessment of quality, because the agencies choose their ratings strategically. I quantify the distortion in ratings for individual commercial mortgage-backed securities, and find the extent of distortion to be an important predictor of the securities' ex post performance. I also find that the distortion magnitudes decreased after the recent financial crisis. Through counterfactual simulations, I determine the marginal impact of additional rating agencies on distortions, and I identify the impact of proposed disclosure requirements.

Keywords: games of incomplete information, auctions, rating agencies, information intermediaries, securitization

JEL Classification: L1, G24