Credit Valuation Adjustment in Credit Risk with Simultaneous Defaults Possibility

TL;DR

This paper extends CVA modeling by relaxing the assumption of conditional independence of defaults, allowing for the possibility of simultaneous defaults, and modifies the associated backward stochastic differential equations accordingly.

Contribution

It introduces a martingale orthogonality condition to model simultaneous defaults in CVA, advancing the theoretical framework beyond classical independence assumptions.

Findings

Modified BSDEs accounting for simultaneous defaults

Enhanced modeling of counterparty risk scenarios

Theoretical foundation for more realistic credit risk analysis

Abstract

In a series of recent papers, Damiano Brigo, Andrea Pallavicini, and co-authors have shown that the value of a contract in a Credit Valuation Adjustment (CVA) setting, being the sum of the cash flows, can be represented as a solution of a decoupled forward-backward stochastic differential equation (FBSDE). CVA is the difference between the risk-free portfolio value and the true portfolio value that takes into account the possibility of a counter party's default. In other words, CVA is the market value of counter party credit risk. This has achieved noteworthy importance after the 2008 financial debacle, where counter party risk played an under-modeled but huge risk. In their analysis, Brigo et al make the classical assumption of conditional independence of the default times, given the risk free market filtration. This does not allow for the increasingly likely case of simultaneous defaults. We weaken their assumption, replacing it with a martingale orthogonality condition. This in turn changes the form of the BSDE that arises from the model.