The paper analyzes a very stylized model of crises and demonstrates how the degree of strategic complementarity in the actions of investors is a critical determinant of fragility. It is shown how the balance sheet composition of a financial intermediary, parameters of the information structure...

We propose a new theory of systemic risk based on Knightian uncertainty (or "ambiguity"). We show that, due to uncertainty aversion, beliefs on future asset returns are endogenous, and bad news on one asset class induces investors to be more pessimistic about other asset classes as well. This...