Document de travail 2009-34
Are Banking Systems Increasingly Fragile ? Investigating Financial Institutions’ CDS Returns Extreme Co-Movements
This paper investigates potential contagion among the major financial institutions in developed economies. Using Credit Default Swaps (CDS) premia as a measure of credit or counterparty risk, our analysis focuses on the extreme co-movements of Financial Institutions' default contracts during the high level of stress undergone by the CDS markets in the aftermath of the 2007 sub-prime crisis. Our approach is twofold: first, under different tail dependence scenarios, we calibrate several multivariate linear propagation models of constant correlation. Our Monte Carlo simulation study finds evidence of contagion for Financial Institutions- notably in the US-and captures a non-normal dependence structure in the tails for the traded contracts. Second, we estimate a multivariate Dynamic Conditional Correlation-GARCH (DCC-GARCH) model, and demonstrate significant ARCH and GARCH effects, as well as time-varying correlations in CDS spreads variations. Our overall analysis rejects the assumption of constant correlation. More importantly, it advocates changing structures in tail dependence for CDS series during times of financial turmoil as an important feature of banks’ increased fragility.
Mots-clés : Bank fragility, Counterparty risk, Financial crises, Extreme co-movements, Conditional correlation, Multivariate GARCH, Monte Carlo simulation