The effects of liquidity trading on insider trade timing when an underlying option is present
Authors: Huang Han Ching , Tung Pei-Shan 
Published: September 2018

Purpose
The purpose of this paper is to examine whether the underlying option impacts an insider’s propensity to purchase and sell before corporate announcements, the proportion of insiders’ trading after announcements relative to before announcements, and the insider’s profitability around corporate announcements.

Design/methodology/approach
The authors test whether the timing information and option have impacted on the tendency of insider trade, the percentage of all shares traded by insiders in the post-announcement to pre-announcement periods and the average cumulative abnormal stock returns during the pre-announcement period.

Findings
Insiders’ propensity to trade before announcements is higher for stocks without options listed than for stocks with traded options. This result is stronger for unscheduled announcements than for scheduled ones. The proportion of insiders’ trade volume after announcements relative to before announcements in stocks that have not options listed is higher than those in stocks with traded options. The positive relationship between the insiders’ signed volume and the informational content of corporate announcements is stronger in stocks without traded options than in stocks with options listed. Insider trades prior to unscheduled announcement are more profitable than those before scheduled ones.

Research limitations/implications
The paper examines whether there is a difference between the effects of optioned stock and non-optioned stock. Roll et al. (2010) use the relative trading volume of options to stock ratio (O/S) to proxy for informed options trading activity. Future research could explore the impact of O/S. Moreover, the authors examine how insiders with private information use such information to trade in their own firms. Mehta et al. (2017) argue that insiders also use private information to facilitate trading (shadow trading) in linked firms, such as supply chain partners or competitors. Therefore, future research could consider the impact of shadow trading.

Social implications
Since the insider’s propensity to buy before announcements in stocks without options listed is larger than in stocks with traded options and the relationship is stronger for unscheduled announcements than for scheduled ones, the efforts of regulators should focus on monitoring insider trading in stocks without options listed prior to unscheduled announcements.

Originality/value
First, Lei and Wang (2014) find that the increasing pattern of insider’s propensity to trade before unscheduled announcements is larger than that before scheduled announcements. The authors document the underlying option has impacted the insider’s propensity to purchase and sell, and the relationship is stronger for unscheduled announcements than for scheduled ones. Second, related studies show insider’s trading activity has shifted from periods before corporate announcements to periods after corporate announcements to decrease litigation risk. This paper find the underlying option has influenced the proportion of insiders’ trading after announcements relative to before announcements when the illegal insider trade-related penalties increase.