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...

Macroprudential stress tests have been employed by regulators in the United States and Europe to assess and address the solvency condition of financial firms in adverse macroeconomic scenarios. We provide a test of these stress tests by comparing their risk assessments and outcomes to those from...

Macroprudential stress tests have been employed by regulators in the United States and Europe to assess and address the solvency condition of financial firms in adverse macroeconomic scenarios. We provide a test of these stress tests by comparing their risk assessments and outcomes to those from...

An intricate web of claims and obligations ties together the balance sheets of a wide variety of financial institutions. Under the occurrence of default, these interbank claims generate externalities across institutions and possibly disseminate defaults and bankruptcy. Building on a simple model...

This paper argues that the U.S. financial crisis is a new type of crisis: a "financial black hole." Financial black holes are characterized by the breaking-up of credit market discipline and the large-scale financing of negative NPV projects. In a theoretical model, we explain how the...

This paper explores financial stability policies for the shadow banking system. I tie policy options to economic mechanisms for shadow banking that have been documented in the literature. I then illustrate the role of shadow bank policies using three examples: agency mortgage real estate...

One of the several regulatory failures behind the global financial crisis that started in 2007 has been the regulatory focus on individual, rather than systemic, risk of financial institutions. Focusing on systemically important assets and liabilities (SIALs) rather than individual financial...

We present a simple model of systemic risk and we show that each financial institution's contribution to systemic risk can be measured as its systemic expected shortfall (SES), i.e., its propensity to be undercapitalized when the system as a whole is undercapitalized. SES increases with the...

We present a network model of the interbank market in which optimizing risk averse banks lend to each other and invest in non-liquid assets. Market clearing takes place through a tâtonnement process which yields the equilibrium price, while traded quantities are determined by means of a...

The paper studies risk mitigation associated with capital regulation, in a context where banks may choose tail risk assets. We show that this undermines the traditional result that higher capital reduces excess risk-taking driven by limited liability. Moreover, higher capital may have an...