Insider trading and firm-specific return volatility

Roll (J Financ 43: 541-566, 1988) argues that firm-specific stock return volatility may result either from informed trading or from noise trading that is unrelated to information. In this paper we provide evidence that insider purchases are inversely related to the idiosyncratic volatility of stocks. We also find that stock idiosyncratic volatilities are generally inversely related to future 6-and 12-month returns. Our results are primarily driven by the timing of insider sales rather than insider purchases. The results are consistent with an information-based explanation of firm-specific return volatility.