The term insider trading refers to the stock transactions of the officers, directors, and large shareholders of a firm. Many investors believe that corporate insiders, informed about their firms' prospects, buy and sell their own firm's stock at favorable times, reaping significant profits. Given the extra costs and risks of an active trading strategy, the key question for stock market investors is whether the publicly available insider-trading information can help them to outperform a simple passive index fund.Basing his insights on an exhaustive data set that captures information on all reported insider trading in all publicly held firms over the past twenty-one years--over one million transactions!--H. Nejat Seyhun shows how investors can use insider information to their advantage. He documents the magnitude and duration of the stock price movements following insider trading, determinants of insiders' profits, and the risks associated with imitating insider trading. He looks at the likely performance of individual firms and of the overall stock market, and compares the value of what one can learn from insider trading with commonly used measures of value such as price-earnings ratio, book-to-market ratio, and dividend yield.

内幕交易是指公司的高级职员、董事和大股东的股票交易。许多投资者认为，企业内部人士在得知公司前景后，会在有利时机买卖自己公司的股票，从而获得可观的利润。考虑到主动交易策略的额外成本和风险，股市投资者的关键问题是，公开的内幕交易信息是否能帮助他们超越简单的被动指数基金基础他对一个详尽的数据集的见解，该数据集收集了所有公开持有的所有内幕交易的信息公司在过去的21年里——超过100万笔交易！--H、 Nejat Seyhun展示了投资者如何利用内幕信息获取优势。他记录了内幕交易后股价变动的幅度和持续时间，内幕人士获利的决定因素，以及与模仿内幕交易相关的风险。他着眼于单个公司和整个股市的可能表现，并将从内幕交易中学到的价值与常用的价值衡量指标（如市盈率、账面市盈率和股息率）进行比较。