In U.S. data 1981–2012, unsecured firm credit moves procyclically and tends to lead GDP, while secured firm credit is acyclical; similarly, shocks to unsecured firm credit explain a far larger fraction of output fluctuations than shocks to secured credit. In this article, we develop a tractable dynamic general equilibrium model in which unsecured firm credit arises from self-enforcing borrowing constraints, preventing an efficient capital allocation among heterogeneous firms. Unsecured credit rests on the value that borrowers attach to a good credit reputation which is a forward-looking variable. We argue that self-fulfilling beliefs over future credit conditions naturally generate endogenously persistent business-cycle dynamics. A dynamic complementarity between current and future borrowing limits permits uncorrelated sunspot shocks to unsecured debt to trigger persistent aggregate fluctuations in both secured and unsecured debt, factor productivity, and output. We show that these sunspot shocks are quantitatively important, accounting for around half of output volatility.

We study a variant of the one-sector neoclassical growth model of Diamond in which capital investment must be credit financed, and an adverse selection problem appears in loan markets. The result is that the unfettered operation of credit markets leads to a one-dimensional indeterminacy of equilibrium. Many equilibria display economic fluctuations which do not vanish asymptotically; such equilibria are characterized by transitions between a Walrasian regime in which the adverse selection problem does not matter, and a regime of credit rationing in which it does. Moreover, for some configurations of parameters, all equilibria display such transitions for two reasons. One, the banking system imposes ceilings on credit when the economy expands and floors when it contracts because the quality of public information about the applicant pool of potential borrowers is negatively correlated with the demand for credit. Two, depositors believe that returns on bank deposits will be low (or high): these beliefs lead them to transfer savings out of (into) the banking system and into less (more) productive uses. The associated disintermediation (or its opposite) causes banks to contract (expand) credit. The result is a set of equilibrium