When Managers Change Their Tone, Analysts and Investors Change Their Tune
研究发现，电话会议中经理用词的负面程度变化（尤其是负面程度上升）能预测未来盈利下降和不确定性增加，而分析师和投资者对此反应不足，据此交易可获超额收益。
The negativity of managerial word choice (managerial tone) in conference calls is a telltale indicator of a company’s future. Specifically, increases in negativity–what we term “bleak tone changes”–strongly predict lower future earnings and increased uncertainty. Decreases in negativity, however, only weakly predict the opposite. To isolate the explanatory power of managerial tone, we controlled for negativity changes in the earnings press release and analysts’ questions. Analysts and investors underreact when they extract value-relevant information from negativity changes. Consequently, a negativity-based trading strategy generates abnormal returns.