Résumé (EN)

We empirically investigate the effect of option listing on the underlying stock pricing efficiency by examining the stock price duration dynamic. We use univariate tests and modified Log-ACD models that account for liquidity. Results indicate that option listing neither damages nor improves the underlying stock efficiency. However, they suggest that a new arrival of informed traders could occur during the trading day as a seasonal feature. We also find a decrease in informed trading for low volume stocks. Furthermore, Euronext and Liffe merger seems to have an impact on the duration process and on the informational content of underlying stocks.