Coruscation

Abstract: We propose a Bayesian methodology that enables banks with
small datasets to improve their default probability estimates by
imposing prior information. As prior information, we use coefficients
from credit scoring models estimated on other datasets. Through
simulations, we explore the default prediction power of three Bayesian
estimators in three different scenarios and find that all three
perform better than standard maximum likelihood estimates. We
therefore recommend that banks consider Bayesian estimation for
internal and regulatory default prediction models.

Keywords: Credit Ratings, Rating Agency, Bayesian Inference, Basel II

JEL Classification: C11, G21, G33