We present a tractable dynamic macroeconomic model of self-fulfilling bank runs. A bank is vulnerable to a run when a loss of investors' confidence triggers deposit withdrawals and leads the bank to default on its obligations. We analytically characterize how the vulnerability of an individual...

We show that if the central bank operates without commitment and faces constraints on its balance sheet, helicopter drops can be a useful stabilization tool during a liquidity trap. With commitment, even with balance sheet constraints, helicopter drops are irrelevant