Collateral constraints widely used in models of financial crises feature a pecuniary externality: Agents do not internalize how borrowing decisions taken in "good times" affect collateral prices during a crisis. We show that agents in a competitive equilibrium borrow more than a financial...

Macroprudential policy holds the promise of becoming a powerful tool for preventing financial crises. Financial amplification in response to domestic shocks or global spillovers and pecuniary externalities caused by Fisherian collateral constraints provide a sound theoretical foundation for this...