Banks, Relative Performance, and Sequential Contagion

We develop a multi-period general equilibrium model of bank deposit, credit, and interim inter-bank loan markets in which banks initially specialize in their choices of debtors, leading to under-diversification, but nevertheless become entwined via inter-bank markets, leading to the fortunes of one bank affecting the profits and default rates of the other in a sequential manner. Lack of (full) diversification among credit risks arises in our model owing to a relative profit argument in each banker's utility function, which is otherwise risk- and default-averse. We examine its implications for the welfare of depositors and debtors.