In this paper we present a tree model for defaultable bond prices which can be used for the pricing of credit derivatives. The model is based upon the two-factor Hull-White (1994) model for default-free interest rates, where one of the factors is taken to be the credit spread of the defaultable...

The market model of interest rates specifies simple forward or Libor rates as lognormaly distributed, their stochastic dynamics has a linear volatility function. This model is extended to quadratic volatility which is the product of a quadratic polynomial and a level-independent covariance...

It is well-known that Gaussian hedging strategies are robust in the sense that they always lead to a cost process of bounded variation and that a superhedge is possible if upper bounds on the volatility of the relevant processes are available, cf. El Karoui, Jeanblanc-Picque and Shreve (1998)...