The internal rate of return of the Mozal project has been calculated using the projected cash flows presented in the exhibit 6 of case study, however, the projected cash flows also show an outflow of funds for the dividend payments and interest payments on subordinate debt, which should not be deducted because they are part of the owner’s withdrawal. Meanwhile, due to the nature of subordinate debts they are also like an equity,therefore, a revised cash flow has been calculated in appendix 1. However, the IRR calculated using the projected cash flows return a yield of 13.43%, meanwhile, the real expected return has been calculated using the capital asset pricing model CAPM which required inflation index rate.