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 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'...

This paper studies how financial information frictions can generate sentiment-driven fluctuations in asset prices and self-fulfilling business cycles. In our model economy, exuberant financial market sentiments of high output and high demand for capital increase the price of capital, which...

We formalize the Keynesian insight that aggregate demand driven by sentiments can generate output fluctuations under rational expectations. When production decisions must be made under imperfect information about demand, optimal decisions based on sentiments can generate stochastic...

We examine global dynamics under infinite-horizon learning in New Keynesian models where the interest-rate rule is subject to the zero lower bound. As in Evans, Guse and Honkapohja (2008), the intended steady state is locally but not globally stable. Unstable deflationary paths emerge after...

We characterize the entire set of linear equilibria of beauty contest games under general information structures. In particular, we focus on equilibria in which sentiments, that is self-fulfilling changes in beliefs that are orthogonal to fundamentals and exogenous noise, can drive aggregate...