The Impact of Default Correlations on the Prices of Collateralized Bond Obligat

This paper presents a numerical procedure for pricing collateralized bond obligations (CBO) and analyze the impact of default correlations for the prices of collateralized bond obligations. Specifically, we adopt default correlation model of Zhou (2001) and first passage time model of Black and Cox (1976). The model of Black and Cox is used for estimating the value of the firm and the volatility of the firm value which are unobservable variables. We find that the impact of default correlations on the prices of collateralized bond obligations is generally quite large. This can be tested by carrying out Monte-Carlo simulations for firm value processes, assuming first no default correlations and second modeling default correlations between the processes. We also compare the model prices and recently issued CBO market price and find that no default correlation model over prices the issued CBO and default correlation model under prices the issued CBO. These results in this paper emphasize that modeling default correlations is very important in analyzing CBO and a more complicated further analysis is required.