Weighted average price in the Heston stochastic volatility model

We propose a weighted average formulation for the Heston stochastic volatility option price to avoid the estimation of the initial volatility. This approach has been developed in the literature for the estimation of the distribution of stock price changes (returns), showing an excellent agreement with real market data. We extend this method to the calibration of option prices considering a large class of probability distributions assumed for the initial volatility parameter. The estimation error is shown to be less than the case of the simple pricing formula. Our results are also validated with a numerical comparison on observed call prices, between the proposed calibration method and the classical approach.