Based on the analyses throughout the case study, it is recommended that the use of a model that assumes an ESO is European style when, in fact, the option is American style with the other exotic variables should not be permitted, as this substantially overstates compensation expenses.
2010, Johnathan Mun, Modeling Risk + DVD: Applying Monte Carlo Risk Simulation, Strategic Real Options, Stochastic Forecasting, and Portfolio Optimization (Second Edition), John Wiley & Sons