医疗产品披露的市场反应异象:来自公共卫生事件压力下“双系统理论”的证据

Stock market anomaly of medical drugs and instruments information disclosure:Evidence from the “Dual System Theory”under the pressure of public health emergency

公共卫生事件引发恐慌的同时,也激发了投资者对相关医疗产品的关注.本文手工搜集事件期间上市公司的医疗产品信息披露公告,研究了投资者对与事件明确相关、模糊相关及完全不相关的三类公告的市场反应.实证研究结果显示,与事件明确相关和模糊相关的医疗产品公告的市场反应没有显著差异,存在异象.进一步地,本文发现存在明星分析师跟踪、事件影响轻微和不存在相关网络谣言时,投资者不会对模糊相关医疗产品信息产生过度反应.本文的研究表明在公共卫生事件压力下,投资者的直觉系统越过理智系统直接作用,而当投资者接受到较多理性信息和事件压力较小时,理智系统能够修正直觉系统产生的认知偏差.

Investors paid more attention to the medical drugs and instruments related to public health emergency after the fast spread of virus in 2020.This paper manually collects the announcements of the listed companies which disclosed the information of medical drugs and instruments during the event period and examines the different market reactions of investors to three types of announcements:Those which are clearly related to the event,fuzzy related to the event,and completely unrelated to the event.Our empirical results show that there are positive market reactions when the announcements are “clear” and “fuzzy”;though,the market reactions for the two types of announcements show no significant difference.Further,the paper finds that investors will not overreact to the “fuzzy” announcements when listed companies were tracked by star analysts,when the situation is not serious,and when there are no related rumors.These results show that under the pressure of public health emergency,the intuitive system of investors directly acts on the deliberation system.When investors receive more rational information and when the pressure of public health emergency is low,the deliberation system could correct the cognitive bias generated by the intuitive system.