The degree of endemic volatility in the number of firms and establishments varies considerably across industries. Examining the within-industry range of variation (max.-min.) of the number of firms over our sample period, the low and high values across U.S. manufacturing industries are 4 and...

This paper shows the importance of technological synergies among heterogeneous firms for aggregate fluctuations. First, we document six novel empirical facts using microdata that suggest the existence of important technological synergies between trading firms, the presence of positive...