We study how messages on Twitter by large non-governmental organizations (NGOs), targeting companies from the S&P500, affect these companies’ stock prices. With a sample of 1,611 tweets between 2009 and 2017 by 18 large NGOs, we observe significant changes in the stock prices of the targeted firms. More specifically, NGO tweets stating a positive message about the environmental, social, or governance (ESG). Actions of the firm have a positive effect on stock prices, while negative tweets have a negative effect. Nevertheless, we find that the presence of institutional owners hampers this effect: firms with high institutional ownership value positive tweets more negatively, and negative tweets more positively. These results support the idea that shareholders react significantly to NGO tweets but they react differently depending on their time horizon: for shareholders who have a more short-term horizon, typically institutional owners, the reaction diverges societal expectations about how firms should contribute to society.

我们研究了大型非政府组织（NGO）在Twitter上针对标普500指数公司的消息如何影响这些公司的股价。我们利用18家大型非政府组织在2009年至2017年间发布的1,611条推文样本，观察到目标公司的股价发生了重大变化。更具体地说，非政府组织的推文表明了有关环境，社会或治理（ESG）的积极信息。公司的行为对股价产生正面影响，而负面推文则产生负面影响。但是，我们发现机构所有者的存在会阻碍这种影响：具有较高机构所有权的公司对负面推文的评价更高，而对负面推文的评价则更高。