Dynamic Hedging of Portfolio Credit Derivatives

Abstract

We compare the performance of various hedging strategies for index CDO tranches across a variety of models and hedging methods during the recent credit crisis. Our empirical analysis shows evidence for market incompleteness: a large proportion of the risk in CDO tranches appears to be unhedgeable. We also show that, unlike what is commonly assumed, dynamic models do not necessarily perform better the static models, nor do high-dimensional bottom-up models perform better than simpler top-down models. Moreover, top-down and regression-based hedging would have provided significantly better hedges than bottom-up hedging with single name CDS during the Lehman Brothers default event. Our empirical study also reveals that while significantly large moves - "jumps" - do occur in the CDS, index and tranche spreads, these jumps do not necessarily occur on default dates of index constituents, an observation which contradicts the intuition conveyed by some recently proposed credit risk models.

Keywords: hedging, portfolio credit derivatives, index default swaps, collateralized debt obligations, top-down credit risk models, default contagion, spread risk, sensitivity-based hedging, risk minimization

JEL Classification: G13, G12