Pricing and Informational Efficiency of the Mib30 Index Options Market. An Analysis with High Frequency Data

Abstract

We analyze the pricing and informational efficiency of the Italian market for options written on the most important stock index, the MIB30. We find several indications inconsistent with the hypothesis that the Italian MIBO is an efficient market. We report that a striking percentage of the data consists of option prices violating basic no-arbitrage conditions. This percentage declines but never becomes negligible when we relax the no-arbitrage restrictions to accommodate for the presence of bid/ask spreads and other frictions. The result holds in general for all levels of moneyness and time to maturity. We also investigate the informational efficiency of the MIBO and conclude that option prices are poor predictors of the volatility of MIB30 returns. This conclusion is robust to a number of statistical and sampling methods.

Keywords: Option pricing, arbitrage, informational efficiency, MIB30 index

JEL Classification: G13, G14