Options and Earnings Announcements : An Empirical Study of Volatility, Trading Volume, Open Interest and Liquidity

In this paper we study the impact of earnings announcements on trading volume, open interest and spreads in the stock option market. We find that option volume is higher around announcement days, even if we correct for stock volume and the expected future volatility of stock returns. Results in the pre-event period are different for good and bad news samples, indicating that option traders have access to (possibly short lived) private information. During the days before the announcements open interest tends to increase. After the earnings news dissemination traders seem to lose interest in the contracts and cancel part of their option positions thereby reducing open interest to normal levels. Analysis of quoted spreads provide no evidence of dealers' anticipation of higher information asymmetry in the pre- or post announcement period. However, results for effective spreads indicate that the transaction costs are higher on the announcement day itself and on the day immediately following the earnings dissemination. Both quoted and effective spreads are shown to respond to changes in trading volume and expected return variability