Strategic Illegal Insider Trading Prior to Price Sensitive Announcements

It is found that insiders are more likely to trade on high volume days, which indicates an effort to hide their trades. Further, insider trading raises the number of days with abnormally high trading volume only slightly, again indicating that insiders are avoiding attracting attention. No evidence is found that insider trading intensity increases on the insider trading day closest to the announcement day. The hypothesis that index returns for insider trading days and non-trading days are the same cannot be rejected, which is consistent with insiders avoiding detection. For stocks sold by insiders, returns are higher for insider trading days than for non-insider trading days. Hence, insiders are selling on days when the market is up, which tends to hide their trading. But for stocks bought by insiders, returns are significantly higher on insider trading days than on non-insider-trading days, indicating that in this case insiders may attract unwanted attention