Diverging Trends in Aggregate and Firm Volatility
记录了销售增长率在总体和企业层面波动趋势的分化，指出企业波动上升并非样本偏差所致，并质疑现有对总体波动下降的解释，提出一个统一的理论。
This note documents the diverging trends in volatility of the growth rate of sales at the aggregate and firm levels. We establish that the upward trend in firm volatility is not simply driven by a compositional bias in the sample studied.We argue that this new fact brings into question the proposed explanations for the decline in aggregate volatility and that, given the symmetry of the diverging trends at the micro and macro levels, a common explanation is likely. We conclude by describing one such theory. Copyright by the President and Fellows of Harvard College and the Massachusetts Institute of Technology.