"This paper finds strong evidence of time-variations in the joint distribution of returns on a stock market portfolio and portfolios tracking size--and value effects. Mean returns, volatilities and correlations between these equity portfolios are found to be driven by underlying regimes that...

"We analyze the volatility surface vs. moneyness and time to expiration implied by MIBO options written on the MIB30, the most important Italian stock index. We specify and fit a number of models of the implied volatility surface and find that it has a rich and interesting structure that...