In addition, the main result is robust to alternative research designs. First, we apply alternative measures of provincial public health threats and obtain consistent inferences. Second, we add a falsification test by generating a pseudo-threat. We do not find a significant relation between abnormal return and pseudo-threat, which strengthens our inferences. Third, we address endogeneity concerns by applying an instrumental variable approach. Specifically, following prior related research [9,10], we use immigrant ratio and emigrant ratio as instruments. Our inferences keep unchanged.