Abstract
Seyhun (1986) argues that insider buying
predicts positive future returns, while insider selling reveals only a slight
signal to predict negative future returns, possibly to satisfy liquidity needs.
Gao et al. (2021) find that insiders are afraid of exposure to litigation risk,
they neither sell their stocks on bad news nor buy, so insiders keep silent.
Based on Gao et al. (2021), we construct the portfolio, which is to buy the
“insider sell” group and to sell the “insider silence” group. According to
Johnson and So (2012), the O/S portfolio is constructed based on the ratio of
individual stock options to the trading volume of the underlying stock. F/S
portfolio is constructed by the ratio of individual stock futures to the
trading volume of the underlying stock. We find that under the holding period
of more than one year, the performance of insider trading strategy is better
than other strategies. Specifically, “buying insider purchases and selling
insider sales” strategies are more profitable with longer holding periods.
Moreover, the longer the holding period of OS and FS strategies, the greater
the negative return effect.
JEL classification numbers: G11, G12, G14.
Keywords: Insider trading, Insider silence, OS strategy, FS strategy,
and one- dimensional strategy.