  The aim of this work is to introduce a new stochastic volatility model for
equity derivatives. To overcome some of the well-known problems of the Heston
model, and more generally of the affine models, we define a new specification
for the dynamics of the stock and its volatility. Within this framework we
develop all the key elements to perform the pricing of vanilla European options
as well as of volatility derivatives. We clarify the conditions under which the
stock price is a martingale and illustrate how the model can be implemented.
