Financial contagion in a core-periphery interbank network

This paper studies financial contagion in a core-periphery interbank network where core banks are large in balance sheet size while periphery banks are smaller and link only with the core banks. Core banks are all bilaterally linked and intermediate liquidity for periphery banks. We establish analytic conditions under which financial contagion propagates in the core-periphery network and examine the extent to which heterogeneity associated with size and number of banks affects these conditions. We show that the failure of core banks does not necessarily imply contagious failure of periphery banks; the core-periphery network structure exhibits a 'robust-yet-fragile' tendency with increased size of core banks; and the resilience of the network to contagion depends on the number of core banks, the number of periphery banks, and the level of interbank liquidity intermediated between the core banks. We also find that, under certain conditions, the core-periphery network is more resilient than the complete network with increased size of core banks.