Bei der Kreditrisikobewertung müssen die Parameter Ausfallwahrscheinlichkeit und korrelation geschätzt werden. Diese Schätzung erfolgt unter Unsicherheit. In der Literatur werden asymptotische Konfidenzregionen diskutiert, um diese Unsicherheit bei der simultanen Schätzung beider Parameter...

The use of probability of default estimates to assess the risks of a credit portfolio should not ignore estimation uncertainty. The latter can be quantified by confidence intervals. But assumptions about dependencies of these intervals are inconsistent with assumptions of conventional credit...

We highlight important and specific characteristics of default risk and methodological implications. In a simulation contrasting independent, Gaussian and Clayton copulas, we also show that joint default probabilities might be a hidden source of risk in conventional portfolio models of default

Robustness of credit portfolio models is of great interest for financial institutions and regulators, since misspecified models translate to insufficient capital buffers and a crisis-prone financial system. In this paper, we propose a method to enhance credit portfolio models based on the model...

This article seeks to make an assessment of estimation uncertainty in a multi-rating class loan portfolio. Relationships are established between estimation uncertainty and parameters such as probability of default, intra- and inter-rating class correlation, degree of inhomogeneity, number of...

In this paper we stress-test credit portfolios of 28 German banks based on a Mertontype multi-factor credit risk model. The ad-hoc stress scenario is an economic downturn in the automobile industry that constitutes an exceptional but plausible event suggested by historical data. Rather than on a...

We put forward a Merton-type multi-factor portfolio model for assessing banks’ contributions to systemic risk. This model accounts for the major drivers of banks’ systemic relevance: size, default risk and correlation of banks’ assets as a proxy for interconnectedness. We measure systemic...

Regulatory capital for trading book positions includes two components that cover different risks but apply to the same portfolio, one for market risk and one for credit risk. Similar approaches are common in banks’ internal models for economic capital. Although it is known that joint market...

In recent years new methods and models have been developed to quantify credit risk on a portfolio basis. CreditMetrics (tm), CreditRisk+, CreditPortfolio (tm) are among the best known and many others are similar to them. At first glance they are quite different in their approaches and...

Stress testing, at its most general level, is an investigation of the performance of an entity under abnormal operating conditions. The authors focus on one set of entities — the Canadian banking sector — and investigate losses in the loans portfolio of this sector as a function of changing...