Rollover risk imposes market discipline on banks’ risk-taking behavior but it can be socially costly. I present a two-sided model in which a bank simultaneously lends to a firm and borrows from the short-term funding market. When the bank is capital constrained, uncertainty in asset quality and rollover risk create a negative externality that spills over to the real economy by ex-ante credit contraction. Macro prudential and monetary policies can be used to reduce the social cost of market discipline and improve efficiency.