We propose a formal re-definition of the concept market failure based on the idea of the imperfect state. In the Neo-classical taxonomy, a decentralized regime of exchange is a market failure if its laissez faire equilibrium solution is welfare-dominated by a technically feasible alternative. If...

The information content of option implied volatility and realized volatility under market imperfections are studied in the context of GARCH modeling and volatility forecasts of Taiwan stock market (TAIEX) returns. Consistent with most studies, we find that the Taiwan implied volatility index...