This paper examines the returns of stocks most frequently held by members of the US Congress surrounding the amendment to the “Stop Trading on Congressional Knowledge” (STOCK) Act, which relaxed some of the restrictions that kept congressional staffers from trading on non-public information. Using a series of standard event study techniques, we find evidence that the stocks held most by members of Congress outperformed the market during the period immediately surrounding the amendment’s passage. Our results are robust to different treatment samples, various methods of calculating abnormal returns, and a number of different placebo tests. In addition, our multivariate tests show that the positive CARs surrounding the amendment are driven by the number of congressmen holding the stock and the amount invested by members of Congress in a particular stock.

中文翻译：

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美国股票法修正案与国会多数持有的股票价格

本文考察了美国国会议员最常持有的股票的回报，围绕“停止根据国会知识进行交易”（STOCK）法案的修正案，该法案放宽了一些限制国会工作人员进行非公开信息交易的限制. 使用一系列标准事件研究技术，我们发现有证据表明，国会议员持有的股票在紧随修正案通过的那段时间内跑赢了市场。我们的结果对不同的治疗样本、计算异常回报的各种方法以及许多不同的安慰剂测试都是稳健的。此外，