Why should risk management systems account for parameter uncertainty? In order to answer this question, this paper lets an investor in a credit portfolio face non-diversifiable estimation-driven uncertainty about two parameters: probability of default and asset-return correlation. Bayesian...

In the work of the Basel Committee there has been a tradition ofdistinguishing market from credit risk and to treat both categories independentlyin the calculation of risk capital. In practice positionsin a portfolio depend simultaneously on both market and credit riskfactors. In this case, an...

The present paper shows how the parameters of three popular portfolio credit risk models can be empiricallyestimated by banks using a Maximum Likelihood framework. We apply the method to a database of Germanfirms provided by Deutsche Bundesbank and analyze the inclusion of macroeconomic and...

Gegenwärtig vergeht kaum ein Tag, an dem in der Wirtschaftspresse nicht über die geplanten Änderungen des internationalen und damit auch europäischen und deutschen Bankenaufsichtsrechts berichtet wird. Insbesondere Stellungnahmen der Betroffenen füllen die Gazetten. Neben allgemeiner...

Starting from the Merton framework for firm defaults, we provide theanalytics and robustness of the relationship between defaultprobabilities and default correlations. We show that loans with higherdefault probabilities will not only have higher variances but also highercorrelations with other...

Under a new Basel capital accord, bank regulators might use quantitative measures when evaluating the eligibility of internal credit rating systems for the internal ratings based approach. Based on data from Deutsche Bundesbank and using a simulation approach, we find that it is possible to...