"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 strongly departs from a constant volatility, Black-Scholes benchmark …

support for the "distressed prepayment" theory that very delinquent loans are more likely to prepay than to default and that …