Competition policy in the banking sector is complicated by the necessity of maintaining financial stability. Greater competition may be good for (static) efficiency, but bad for financial stability. From the point of view of welfare economics, the relevant question is: What are the efficient...

We present a model that can explain a sudden drop in the amount of money that can be borrowed against an asset, even in the absence of asymmetric information or fears about the value of the collateral. Three features of the model are essential: (i) the debt has a much shorter tenor than the...

A complex financial system comprises both financial markets and financial intermediaries. We distinguish financial intermediaries according to whether they issue complete contingent contracts or incomplete contracts. Intermediaries such as banks that issue incomplete contracts, e.g., demand...

We define a financial system to be fragile if small shocks have disproportionately large effects. In a model of financial intermediation, we show that small shocks to the demand for liquidity cause either high asset-price volatility or bank defaults or both. Furthermore, as the liquidity shocks...