Estimation Uncertainty in Credit Risk Assessment: Comparison of Credit Risk Using Bootstrapping and an Asymptotic Approach
Henry Dannenberg
IWH Discussion Papers,
No. 3,
2009
Abstract
For credit risk assessment, probability of default and correlation have to be estimated simultaneously. However, these estimates are uncertain. To assess this uncertainty the literature has discussed the use of asymptotic confidence regions. This kind of region though needs a long credit history for exact assessment. An alternative method to generate a confidence region for a short credit history is bootstrapping. Hence, it could be more appropriate to assess estimation uncertainty with bootstrapping than with asymptotic methods if only a short credit history is available. Based on a simulation study, it is analyzed how many periods should be available for assessing credit risk – taking account of estimation uncertainty – if bootstrapping and a Wald confidence region shall achieve similar results. This article shows that more than 100 cycles have to be available for similar results.
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An Assessment of Bank Merger Success in Germany
Michael Koetter
German Economic Review,
No. 2,
2008
Abstract
German banks have experienced a merger wave since the early 1990s. However, the success of bank mergers remains a continuous matter of debate.This paper suggests a taxonomy to evaluate post-merger performance on the basis of cost and profit efficiency (CE and PE). I identify successful mergers as those that fulfill simultaneously two criteria. First, merged institutes must exhibit efficiency levels above the average of non-merging banks. Second, banks must exhibit efficiency changes between merger and evaluation year above efficiency changes of non-merging banks. I assess the post-merger performance up to 11 years after the mergers and relate it to the transfer of skills, the adequacy to merge distressed banks and the role of geographical distance. Roughly every second merger is a success in terms of either CE or PE. The margin of success in terms of CE is narrow, as efficiency differentials between merging and non-merging banks are around 1 and 2 percentage points. PE performance is slightly larger. More importantly, mergers boost in particular the change in PE, thus indicating persistent improvements of merging banks to improve the ability to generate profits.
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The Impact of Competition on Bank Orientation
Hans Degryse, Steven Ongena
Journal of Financial Intermediation,
No. 3,
2007
Abstract
How do banks react to increased competition? Recent banking theory significantly disagrees regarding the impact of competition on bank orientation—i.e., the choice of relationship-based versus transactional banking. We empirically investigate the impact of interbank competition on bank branch orientation. We employ a unique data set containing detailed information on bank–firm relationships. We find that bank branches facing stiff local competition engage considerably more in relationship-based lending. Our results illustrate that competition and relationships are not necessarily inimical.
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Schätzunsicherheit oder Korrelation, Welche Risikokomponente sollten Unternehmen bei der Bewertung von Kreditportfoliorisiken wann berücksichtigen?
Henry Dannenberg
IWH Discussion Papers,
No. 5,
2007
Abstract
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 portfolio models. Based on simulation studies this paper shows, that a model which include estimation uncertainty but ignore default correlation might estimate the real credit risk more correctly than a model that implicates default correlation but ignore estimation uncertainty. The latter is a trait of conventional credit portfolio models. In this paper quantifying of estimation uncertainty based on the idea of confidence intervals and the underlying probability distributions of these intervals.
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Repercusiones de la integración y consolidación de los sectores bancarios europeos sobre la innovación y las actividades de los emprendedores
Hans Degryse, Steven Ongena, Maria Fabiana Penas
Papeles de Economía Española,
No. 110,
2006
Abstract
We investigate whether the agenda of deepening the integration of the European financial sector may hurt innovation and growth in Europe. In particular we highlight the problems financial integration may create for breakthrough innovation. Financial integration, by escalating competition and consolidation in the European banking sector, may jeopardize the funding of radical innovators. However weighing the current evidence we conclude these problems may at most be transitory.
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Measurement Matters — Alternative Input Price Proxies for Bank Efficiency Analyses
Michael Koetter
Journal of Financial Services Research,
No. 2,
2006
Abstract
Most bank efficiency studies that use stochastic frontier analysis (SFA) employ each bank’s own implicit input price when estimating efficient frontiers. But at the same time, most studies are based on cost and/or profit models that assume perfect input markets. Traditional input price proxies therefore contain at least substantial measurement error. We suggest here two alternative input market definitions to approximate exogenous input prices. We have access to Bundesbank data, which allows us to cover virtually all German universal banks between 1993 and 2003. The use of alternative input price proxies leads to mean cost efficiency that is significantly five percentage points lower compared to traditional input prices. Mean profit efficiency is hardly affected. Across models, small cooperative banks located in large western states perform best while large banks and those located in eastern states rank lowest.
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Are European Equity Style Indexes Mean Reverting? Testing the Validity of the Efficient Market Hypothesis
Marian Berneburg
IWH Discussion Papers,
No. 193,
2004
Abstract
The article tests for a random walk in European equity style indexes. After briefly
introducing the efficient market hypothesis, equity styles in general and the used
statistical techniques (Variance Ratio Test and modified Rescaled Range Test) it is
shown that a random walk in European equity style indexes cannot be rejected. At least in the period since the mid 70s, for which this research has been conducted, the weak form efficient market hypothesis seems to hold.
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