Abstract: | In this study I examine the effect of organized options trading on stock price behavior immediately following stock price declines of 10 percent or more. A matched-pair sample of National Market System option and nonoption firms are analyzed from June 1985 through December 1992. After controlling for the bid-ask bounce, firm size, share price, return standard deviation, and beta, I find that three-day cumulative abnormal returns for option firms are approximately 1.57 percent less than those for nonoption firms. Thus, options trading enhances stock market efficiency and/or liquidity. However, no profitable trading strategies are indicated. |