Securitization, Ratings, and Credit Supply

Abstract

We develop a framework to explore the effect of credit ratings on loan origination and securitization. In the model, banks privately screen and originate loans and then issue securities that are backed by loan cash flows. Issued securities are rated and sold to investors.

Without ratings, banks with good loans retain a portion of them to signal quality to investors. With informative ratings, banks rely less on costly retention and more on public information. Moreover, when ratings are sufficiently accurate, banks may eschew retention altogether and simply originate to distribute (OTD). Thus, ratings endogenously shift the economy from a Signaling equilibrium with inefficient retention towards an OTD equilibrium with inefficiently low lending standards. Ratings therefore increase overall efficiency provided the reduction in costly retention more than compensates for the origination of some negative NPV loans. We study how banks ability to screen loans affects these predictions, and use the model to analyze commonly proposed policies such as mandatory “skin in the game.”

Keywords: Loan Origination, Securitization, Credit Supply, Ratings

JEL Classification: G01, G21, G28