We present an incomplete markets model to understand the costs and benefits of increasing government debt in a low interest rate environment. Higher risk increases the demand for safe assets, lowering the natural rate of interest below zero, constraining monetary policy at the zero lower bound,...

We present a model in which temporary shocks can permanently scar the economy's productive capacity. Unemployed workers lose skill and are expensive to retrain, generating multiple steady state unemployment rates. Large temporary shocks push the economy into a liquidity trap, generating...