This paper sets out a tractable model which illuminates problems relating to individual bank behaviour, to possible contagious inter-relationships between banks, and to the appropriate design of prudential requirements and incentives to limit ‘excessive’ risk-taking. Our model is rich enough to include heterogeneous agents, endogenous default, and multiple commodity, and credit and deposit markets. Yet, it is simple enough to be effectively computable and can therefore be used as a practical framework to analyse financial fragility. Financial fragility in our model emerges naturally as an equilibrium phenomenon. Among other results, a non-trivial quantity theory of money is derived, liquidity and default premia co-determine interest rates, and both regulatory and monetary policies have non-neutral effects. The model also indicates how monetary policy may affect financial fragility, thus highlighting the trade-off between financial stability and economic efficiency. Copyright Springer-Verlag Berlin/Heidelberg 2006Financial fragility, Commerical banks, General equilibrium, Default, Incomplete markets, Monetary policy, Regulatory policy.,

The objective of this paper is to propose a model to assess risk for banks. Its main innovation is to incorporate endogenous interaction between banks, recognising that the actual risk to which an individual bank is exposed also depends on its interaction with other banks and other private sector agents. To this end, we develop a two-period general equilibrium model with three active heterogeneous banks, incomplete markets, and endogenous default. The setting of three heterogeneous banks allows us to study not only interaction between any two individual banks, but also their interaction with the rest of the banks in the banking system. We show that the model is analytically tractable and can be calibrated against real UK banking data and therefore can be implemented as a risk assessment tool for financial regulators and central banks. We address the impact of monetary and regulatory policy as well as credit and capital shocks in the real and financial sectors.