Arbeitspapier

A hierarchical model of tail dependent asset returns for assessing portfolio credit risk

This paper introduces a multivariate pure-jump Lévy process which allows for skewness and excess kurtosis of single asset returns and for asymptotic tail dependence in the multivariate setting. It is termed Variance Compound Gamma (VCG). The novelty of my approach is that, by applying a two-stage stochastic time change to Brownian motions, I derive a hierarchical structure with different properties of inter- and intra-sector dependence. I investigate the properties of the implied static copula families and come to the conclusion that they are ordered with respect to their parameters and that the lower-tail dependence of the intra-sector copula is increasing in the absolute values of skewness parameters. Furthermore, I show that the joint characteristic function of the VCG asset returns can be explicitly given as a nested Archimedean copula of their marginal characteristic functions. Applied to credit portfolio modelling, the framework introduced results in a more conservative tail risk assessment than a Gaussian framework with the same linear correlation structure, as I show in a simulation study. To foster the simulation efficiency, I provide an Importance Sampling algorithm for the VCG portfolio setting.

ISBN
978-3-86558-783-1
Language
Englisch

Bibliographic citation
Series: Discussion Paper Series 2 ; No. 2011,16

Classification
Wirtschaft
Specific Distributions; Specific Statistics
Computational Techniques; Simulation Modeling
Asset Pricing; Trading Volume; Bond Interest Rates
Banks; Depository Institutions; Micro Finance Institutions; Mortgages
Subject
Portfolio Credit Risk
Stochastic Time Change
Brownian Subordination
Jumps
Tail Dependence
Hierarchical Dependence Structure

Event
Geistige Schöpfung
(who)
Puzanova, Natalia
Event
Veröffentlichung
(who)
Deutsche Bundesbank
(where)
Frankfurt a. M.
(when)
2011

Handle
Last update
10.03.2025, 11:43 AM CET

Data provider

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Object type

  • Arbeitspapier

Associated

  • Puzanova, Natalia
  • Deutsche Bundesbank

Time of origin

  • 2011

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