Default probability estimation in small samples - with an application to sovereign bonds

Orth, Walter (2011): Default probability estimation in small samples - with an application to sovereign bonds. Unpublished.

Abstract

In small samples and especially in the case of small true default probabilities, standard approaches to credit default probability estimation have certain drawbacks. Most importantly, standard estimators tend to underestimate the true default probability which is of course an undesirable property from the perspective of prudent risk management. As an alternative, we present an empirical Bayes approach to default probability estimation and apply the estimator to a comprehensive sample of Standard & Poor's rated sovereign bonds. We further investigate the properties of a standard estimator and the empirical Bayes estimator by means of a simulation study. We show that the empirical Bayes estimator is more conservative and more precise under realistic data generating processes.

• Item Type: MPRA Paper
• Language: English
• Keywords: Low-default portfolios; empirical Bayes; sovereign default risk; Basel II
• Subjects: C - Mathematical and Quantitative Methods > C4 - Econometric and Statistical Methods: Special Topics > C41 - Duration Analysis; G - Financial Economics > G1 - General Financial Markets > G15 - International Financial Markets; G - Financial Economics > G2 - Financial Institutions and Services > G28 - Government Policy and Regulation; C - Mathematical and Quantitative Methods > C1 - Econometric and Statistical Methods: General > C11 - Bayesian Analysis

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