Aggregate Uncertainty and the Micro-Dynamics of Firms

Using firm level micro-data, I find evidence that firms with lower growth prospects are more sensitive to aggregate shocks. I interpret these findings using a model of demand accumulation and endogenous entry and exit decisions, which I then estimate on French data. The resulting cyclical dynamics of firms provide an explanation for the observed counter-cyclical dispersion in firms' growth rates. They suggest that cyclical dispersion is the result of a pre-existing and persistent characteristic of the firm and caution against its use as a proxy for time-varying uncertainty. The estimated negative correlation between a firm's sensitivity to aggregate shocks and its expected future growth rate is shown to have important consequences for the cyclical characteristics of entering and exiting firms. The quantitative model suggests that this compositional effect is sizeable and equivalent to around 10.5% of the drop in aggregate employment between 2008 and 2009.