Gemäß den im Juni 2004 durch den Baseler Ausschuss endgültig verabschiedeten Kapitalstandards (Basel II) sind Kredite in Höhe des so genannten unerwarteten Verlusts mit Eigenkapital zu unterlegen. Für erwartete Verluste hat das jeweilige Kreditinstitut Rückstellungen zu bilden, wobei hier...

This paper discusses the relationship between bank size and risk-taking under Pillar I of the New Basel Capital Accord. Using a model with imperfect competition and moral hazard, we find that small banks (and hence small borrowers) may profit from the introduction of an internal ratings based...

Within the Internal Ratings-Based (IRB) approach of Basel II it is assumed that idiosyncratic risk has been fully diversi?ed away. The impact of undiversi?ed idiosyncratic risk on portfolio Value-at-Risk can be quanti?ed via a granularity adjustment (GA). We provide an analytic formula for the...

We show that the saddle-point approximation method to quantify the impact of undiversi?ed idiosyncratic risk in a credit portfolio is inappropriate in the presence of double default effects. Speci?cally, we prove that there does not exist an equivalent formula to the granularity adjustment, that...

In 2005 the Internal Ratings Based (IRB) approach of `Basel II' was enhanced by a `treatment of double default effects' to account for credit risk mitigation techniques such as ordinary guarantees or credit derivatives. This paper reveals several severe problems of this approach and presents a...

Default probabilities (PDs) and correlations play a crucial role in the New Basel Capital Accord. In commercial credit risk models they are an important constituent. Yet, modeling and estimation of PDs and correlations is still under active discussion. We show how the Basel II one factor model...

The main challenge of forecasting credit default risk in loan portfolios is forecasting the default probabilities and the default correlations. We derive a Merton-style threshold-value model for the default probability which treats the asset value of a firm as unknown and uses a factor model...