Insider trading and the post‐earnings announcement drift
研究发现公司内部人在盈余公告后的交易行为部分决定了盈余公告后漂移异常的程度，反向交易缓解了市场对盈余公告的反应不足，而确认性交易则推动价格沿盈余惊喜方向持续发现。
Abstract We show that trades by corporate insiders after an earnings announcement determine in part the extent of the post‐earnings announcement drift anomaly. Contrarian trades mitigate the under‐reaction to earnings announcements, and confirmatory trades allow for price discovery with price movements continuing in the same direction as the earnings surprise. These results are consistent with insider trading being a mechanism that provides relevant information on transitory or permanent changes to the earnings process, allowing the market to make appropriate inferences about the nature of the earnings surprise.