Shifts in the extent of competition, which affect markup ratios, are possible sources of aggregate business fluctuations. Markups are countercyclical, and booms are times at which the economy operates more efficiently. We begin with a real model in which markup ratios correspond to the prices of...

The creation of new businesses declines in recessions. In this paper, I study the effects of pro-cyclical business formation on aggregate employment in a general equilibrium model of firm dynamics. The key features of the model are that the elasticity of demand faced by firms falls with their...