The Economics of Credit Rating Agencies

We explore through both an economics and regulatory lens the frictions associated with credit rating agencies in the aftermath of the financial crisis. While ratings and other public signals are an efficient response to scale economies in information production, these also can discourage independent due diligence and be a source of systemic risk. Though Dodd-Frank pulls back on the regulatory use of ratings, it also promotes greater regulation of the rating agencies. We highlight the diverse underlying views towards these competing approaches to reducing systemic risk. Our monograph also discusses the subtle contrasts between credit rating agencies and other types of due diligence providers, such as auditors, analysts and proxy-voting advisors. We discuss the frictions associated with paying for information in the context of credit ratings; while the issuer-pay model has been identified as a major issue because of potential conflict of interests, we argue that it has several advantages over the investor-pay model in promoting market transparency.

We develop a formal reputation model to explore the underlying nature of rating inflation and how the reputational trade-off is affected by various aspects of the rating process such as regulatory constraints, the fee structure, asymmetric information between issuers and investors and the extent of competition among rating agencies. The monograph also uses our illustrative framework to highlight tension between rating accuracy and economic efficiency when ratings influence project value in the presence of feedback effects. We discuss how selective disclosure of ratings by the issuer distorts the distribution of observed ratings. Selection also provides an alternative explanation for why solicited (purchased) ratings exceed unsolicited (complimentary) ratings and helps interpret the greater SEC support for unsolicited ratings in recent years as illustrating the theory of the second best. We explore the impact of greater competition on welfare, building upon a variety of frameworks. Our analysis points to several ways in which ratings matter as well as techniques for documenting such effects.