This paper studies how managers plan under uncertainty. In a new survey panel on German manufacturing firms, we show that uncertainty reflects change: Planning incorporates higher subjective uncertainty about future sales growth when the firm has just experienced unusual growth, and more so if...

Are fluctuations in firms' profitability risk a major cause of regular business cycles? We study this question within the framework of a heterogeneous-firm dynamic stochastic general equilibrium model with fixed capital adjustment costs. In such a model, surprise increases of risk lead to a...