This article proposes a sequential Bayesian updating approach to estimate default probabilities on rating grade level for no- and low-default portfolios. Bayesian sequential updating allows to obtain default probabilities also for those rating grades for which no defaults have been observed. The...

In credit portfolio modeling the asset correlation parameter is used to describe the degree of default rates fluctuations. In this article we estimate the asset correlation parameter for banks and other industry sectors from default data. We find that estimates of the asset correlation vary...

The dependency of the individual default behavior of a firm on the state of the credit cycle is widely implemented in credit portfolio models and ultimately reflected in the Basel II one-factor model determining capital requirements. Despite this, macroeconomic variables able to represent this...

The aim of validating default probabilities is to analyze whether these are not too low. For small sample sizes, however, there are not enough observations available to detect excessively low default probabilities.We therefore propose a modification of default probability validation which...