The paper proposes a sequential Bayesian updating approach to estimate default probabilities on rating grade level for no- and low-default portfolios.Bayesian sequential updating enables default probabilities to be obtained also for those rating grades for which no defaults have been...

The Basel Accord assumes an inverse relationship between the probability of default and the asset correlation parameter, with the latter being responsible for modeling the degree of cyclicality of default rates. Previous empirical studies that embedded the formula of the Basel Accord into a...