This paper examines the dynamics of returns and order imbalances across the KOSPI 200 cash, futures and option markets. The information effect is more dominant than the liquidity effect in these markets. In addition, returns have more predictability power for the future movements of prices than order imbalances. Information seems to be transmitted more strongly from derivative markets to their underlying asset markets than from the underlying asset markets to their derivative markets. Finally, domestic institutional investors prefer futures, domestic individual investors prefer options, and foreign investors prefer stocks relative to other investor groups when they have new information. ?? 2008 World Scientific Publishing Co. and Center for Pacific Basin Business, Economics and Finance Research.