• The Heston model is an option pricing model that uses stochastic volatility.

  • This means that the model assumes that volatility is arbitrary, as opposed to the Black-Scholes model, which assumes volatility is constant.
  • The Heston model is a type of volatility smile model that is a graphical representation of multiple options with the same expiration dates that show increasing volatility as the options become more ITM or OTM.