Working Paper No. 265
By Spyros Pagratis
Using an intertemporal model of asset pricing under asymmetric information, we demonstrate how public ratings about the quality of a risky asset could enhance information efficiency, albeit at a cost of higher asset price volatility. The analysis also draws implications for the use of ratings for benchmarking purposes, in particular, ratings-based capital requirements and an investment/subinvestment grade dichotomy depending on the rating of the asset. In this situation, allowing a class of market participants (eg pension funds) to hold an asset only if its rating exceeds a certain threshold may lead informed traders to overreact to news about fundamentals. In this case, ratings induce lower price efficiency and excessive asset price volatility.