In the Rothschild and Stiglitz model, assuming differences in risk aversions may lead to unusual equilibrium configurations like multiple equilibria, equilibrium positive profits, or random contracts. We characterize the various types of equilibria and give results on the determinants of the...

We discuss the relevance of the volatility as a risk measure. By considering recent studies on tick by tick data and specific features of derivatives, we introduce alternative measures to take into account the time and volume effects, or the distributional asymmetry.