This paper examines novel survey evidence on firms’ beliefs about macroeconomic tail risk and their role in investment decisions. In a large survey of German firms, I elicit (i) the subjective probability of a severe macroeconomic downturn and (ii) firms’ exposure to such an event. I consistently find across different empirical approaches that a higher probability of a severe macroeconomic downturn substantially lowers investment, particularly for firms that report higher exposure to the event. I attribute less than half of the investment response to changes in firms' subjective first and second moments. In a quantitative heterogeneous firm model calibrated to match the survey evidence, firms' concern with tail risk makes fiscal policy particularly effective for stabilizing investment.