Calculate the real resources cost of the investment. The real resource is the amount that the creditors have invested. Add 1 with the risk-free rate of interest, then divide that number by 1 minus the actual premium (see reference 2).
Subtract this solution by 1 to figure out the real resources cost. The risk-free rate is the basis of the assets, but it includes the risk premium (see reference 3).
Calculate the default risk premium. Take the real resource cost and subtract it by the risk-free rate of the interest. The calculation must be in percentage or decimals.
Complete the calculations by adding the risk-free rate to the default risk premium.