Aggregate employment fluctuations with microeconomic asymmetries

We provide a simple explanation for the observation from the U.S. manufactu ring sector that the job destruction rate fluctuates more than the job crea tion rate. In our model, proportional plant-level costs df creating and des troying jobs cause shrinking plants to be more sensitive to aggregate shock s than growing plants. We describe circumstances in which this microeconomi c asymmetry is preserved in the aggregate and show that it can account for much of the observed asymmetries in gross job flows. This is so even though we abstract from job matching frictions, incomplete contracts, and aggrega te congestion effects.