Because inputs are scarce, marginal cost should be an increasing function of output. Without changes in this real marginal cost schedule, aggregate output can vary if and only if the markup of price over marginal cost varies. In this review, we discuss the extent to which observed fluctuations...

This paper is a theoretical study into how credit constraints interact with aggregate economic activity over the business cycle. We construct a model of a dynamic economy in which lenders cannot force borrowers to repay their debts unless the debts are secured. In such an economy, durable assets...

This paper illustrates how fluctuations in aggregate economic activity can result from many small, independent shocks to individual sectors. The effects of the small independent shocks fail to cancel in the aggregate due to the presence of two non-standard assumptions: local interaction between...

The paper presents an intertemporal general equilibrium model with rationing in the product market, in which stationary sunspot equilibria are shown to exist, indicating the possibility of fluctuations in economic activity simply due to self-fulfilling variations in economic agents'...

We develop a variation of the macroeconomic model with banking in Gertler and Kiyotaki (2011) that allows for liquidity mismatch and bank runs as in Diamond and Dybvig (1983). As in Gertler and Kiyotaki, because bank net worth fluctuates with aggregate production, the spread between the expected...

The paper presents a model of a monetary economy where there are differences in liquidity across assets. Money circulates because it is more liquid than other assets, not because it has any special function. There is a spectrum of returns on assets, reflecting their differences in liquidity. The...