This paper investigates stock market reactions to judicial events in the United States Supreme Court (SCOTUS) involving at least one public firm. Using a comprehensive dataset of >500 SCOTUS cases from 1948 to 2018, we find that the stock market reacts significantly to both the grant of and the announcement of the final decision. In particular, the stock market reaction to the petitioner and respondent being granted is significantly negative, portending general higher uncertainty ahead. Furthermore, the stock market reaction to the final decisions for winning (losing) firms is positive (negative). In addition, we find that case characteristics, such as parties involved and the type of legal issue, explain some of the cross-sectional variations in the stock returns across cases. Our tests also show that there is no prior information leakage and no stock price drift following the events.

中文翻译：

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股市是否预测公司案件中的事件和最高法院的判决？

本文调查了股市对美国最高法院 (SCOTUS) 至少涉及一家上市公司的司法事件的反应。使用 1948 年至 2018 年超过 500 个 SCOTUS 案例的综合数据集，我们发现股市对最终决定的批准和宣布做出了显着反应。特别是，股市对申请人和被申请人获得批准的反应明显负面，预示着未来总体不确定性更高。此外，股市对获胜（失败）公司的最终决策的反应是积极的（消极的）。此外，我们发现案例特征（例如涉及各方和法律问题的类型）可以解释不同案例中股票回报率的一些横截面差异。我们的测试还表明，事件发生后不存在事先信息泄露，也不存在股价漂移。