Valuing defaultable bonds: an excursion time approach

Recently there has been some interest in the credit risk literature in models which involve stopping times related to excursions. The classical Black-Scholes-Merton-Cox approach postulates that default may occur, either at or before maturity, when the firm's value process falls below a critical threshold. In the excursion approach the duration of default, the time period from the financial distress announcement through its resolution, is explicitly modeled. In this contribution, we provide a review of the literature on excursion time models of credit risk. Moreover, we examine the effects on credit spreads structure of different specifications of the event that triggers default.