Modern theories of the business cycle do not allow for the simultaneous rational choice of both prices and quantities, instead assuming that an “invisible hand” determines one of these variables to clear markets. In this paper, we develop a macroeconomic framework in which both prices and quantities are chosen directly by firms, and exchange is both voluntary and efficient. Because of uncertainty about demand and productivity, individual product markets can be in excess supply or rationed. The absence of market-clearing changes pricing and production in qualitatively important ways: markups are no longer determined solely by the elasticity of demand, and higher uncertainty reduces production and increases markups. In equilibrium, production in rationed markets has a negative aggregate demand externality on demand in slack markets. Differently from New Keynesian economies, monetary shocks propagate by reducing economic slack, raising aggregate labor productivity and consumption, while uncertainty shocks act as stagflationary cost-push shocks. We integrate our theory of disequilibrium in a dynamic, rational-expectations “New Old Keynesian Model” and demonstrate its implications for the business cycle.
