Title:
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Pricing synthetic CDO tranche on ABS
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This thesis develops a modeling framework for the pricing of a synthetic
Collateralized Debt Obligation on Asset-Backed Securities (CDO on ABS) and
other credit derivatives on ABS. A credit derivative with ABS exposure has
attracted much attention in recent years. As one of the latest innovations in the
financial market, a credit derivative on ABS is different to the traditional credit
derivative in that it sources credit risks from the ABS market, for example the
Sub-Prime mortgage market, rather than from the market for corporate default
risks. The traditional credit risk models are all designed for corporate default risks
however they do not cover some of the unique features associated with an ABS.
Motivated by this modeling discrepancy, in this thesis we design a credit risk
model for the pricing and risk management of credit derivatives on ABS.
The thesis starts with an introduction to some related products and markets. The
difficulties in the construction of a pricing model for credit derivatives on ABS
are outlined and some basic concepts are introduced to simplify the problem. The
foundation of the model is based on a reduced fonn approach, where defaults are
driven by an explicit intensity. A prepayment intensity is also introduced to drive
the dynamics of the future cash flow of an ABS asset. For multiple name products
such as a CDO on ABS, we model the default and prepayment dependency
between each of the single name assets via a copula approach, where the
interdependency of default and prepayment of each single name asset is also
dynamically captured in an integrated framework. A semi analytical solution is
derived for the model via a Fourier transfonn method. Some variance reduction
techniques are also examined for an efficient Monte-Carlo implementation of the
model for pricing and risk calculation purposes. A traditional credit derivative can
also be priced as a special case within our modeling framework.
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