Dissertation- A comprehensive Analysis of Advanced Pricing Models for Collateralized Debt Obligations
The subject of this paper is the single tranche portfolio credit default swap or synthetic single tranche CDO, which has gets a great deal of interest in present years. Unlike single name CDS, tranche portfolio products depend on the joint default behavior of the underlying credits or in other words their default correlation. The Gaussian copula has emerged as a market standard for modeling the dependence structure and pricing CDOs. The introduction of credit shows has made it possible to evaluate a market implied correlation, which for the Gaussian copula results in a smile similar to the volatility smile for the Scholes and Black model in the equity options market. The smile is inconsistent with the model and causes problems for pricing bespoke CDOs. Thus a lot of research has been devoted to develop extensions to the Gaussian copula or/ and alternative pricing models that are better able to illustrate the correlation smile. In this thesis we will review and compare the performance of a number of advanced pricing models for collateralized debt obligations which were currently suggested, including the Base Correlation framework, the double t copula, the NIG copula and two extensions to the normal copula comprising random recovery rates and random factor loadings. The models are assessed in terms of how well they are able to replicate/describe the correlation skew in the index market. The performance of the models is tested over time for both the iTraxx and CDX 5 year index.
