We compare Semi-Nonparametric expansions of the Gamma distribution with alternative Laguerre expansions, showing that they substantially widen the range of feasible moments of positive random variables. Then, we combine those expansions with a component version of the Multiplicative Error Model...

We conduct an extensive empirical analysis of VIX derivative valuation models over the 2004-2007 bull market and the subsequent financial crisis. We show that existing models yield large distortions during the crisis because of their restrictive volatility mean reverting assumptions. We propose...

We derive the statistical properties of the SNP densities of Gallant and Nychka (1987). We show that these densities, which are always positive, are more general than the truncated Gram-Charlier expansions of Jondeau and Rockinger (2001), who impose parameter restrictions to ensure positivity....