The purpose of this study is to examine the impact of the trade-activities in option market on stock market volatility by using KOSPI 200 daily data. First. we divided the option Volume from open interest. then classify the unexpected volume from expected volume to group the trade-activities In option market according to Investor's type. The result of test find that the unexpected volume of call option and the stock volatility have positive relationship. while one of put option and the stock volatility do not have statistically significant relation.
Then. we also divide the option volume Into the classified option volume according to time-maturity. We expect that the informed trader and uninformed trader trade the classified option differently. As a result. in the case of the call ootlon. the trade-activity of the unexpected volume in deep in the money option and deep out 이 the money option has positive relation with the stock volatility. and the at the money option below a month to maturity has positive relation with the stock volatility. This result shows that the informed trader prefer deep in the money option. deep out of the money option and at the money option below a month to maturity among the various option series. But. In the case of put option, it is so hard to find the result of the Informed trader's behavior.
