Entry, Variable Markups, and Business Cycles

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 market share and that adjustment costs slow the reallocation of employment between firms. In response to a decline in entry, incumbent firms' market shares increase, their elasticity of demand falls, and they increase their markups and reduce employment. To quantify the model, I study the relationship between variable input use and revenue in panel data on large firms. Viewed through the lens of my model, my estimates imply that for large firms, the within-firm elasticity of the markup to relative sales is 25 percent. I use the calibrated model to study shocks to entry, finding that a fall in entry can lead to a significant contraction in employment. A shock to entry that replicates the decline in the number of businesses during the Great Recession generates a prolonged 2.5 percent fall in employment in the model. Finally, I show that the declining correlation between revenue and variable input use over the past 30 years implies that the effect of entry on the business cycle has become stronger over time.