Insider Trading Following Material News Events: Evidence from Earnings
研究内幕交易在重大新闻事件（如季度盈余公告）后的模式，发现内幕买入（卖出）活动先于长期异常回报，并探讨监管和公司政策对限制内幕交易的影响。
0 Prior studies indicate that insider buying (selling) activity precedes positive (negative) abnormal returns that persist over relatively long horizons.1 Presumably, investors may benefit from knowledge of previous insider trades, and consistent with this, the financial press and investment advisors frequently provide information on insider trading activity.2 Recent efforts to reduce the incidence of insider trading based on non-public information have originated both from regulatory authorities and companies. Congress has passed several new laws regulating insider trading in the past decade, and the SEC has increased its enforcement of insider trading restrictions (see Arshadi and Eyssell [2, pp. 31-2]). Several companies have also adopted policies that restrict insider trading to time periods following news events such as quarterly earnings announcements. For instance, Compaq has a policy that limits insider transactions to the period following quarterly earnings reports (see Heavy Insider Sales are Made at Compaq, The Wall Street Journal, June 9, 1993).3 The intended effect of such policies is presumably to level the playing field between insiders and external investors and ensure that the firm and its officers comply with the law.