Large corporations often use a higher rate than the risk-free interest rate when calculating the residual value of individual departments or an entire firm. They often called this rate the required rate of return or minimum acceptable rate of return. There are various ways of calculating such a rate, but the main reason it is almost always higher than the rates offered by certificates of deposit is the higher risk involved in a business. After all, investing money in even the safest corporation involves some risk of never again seeing part or all of your money again, whereas a bank deposit is government guaranteed and virtually fail-proof. Therefore, businesses consider themselves to be adding economic value only if they can surpass a higher benchmark than the risk-free interest rate offered by banks.
Now that we've found how to compute residual income, we must now use this information to formulate a true value estimate for a firm. Like other absolute valuation approaches, the concept of discounting future earnings is put to use in residual income modeling as well. The intrinsic, or fair value, of a company's stock using the residual income approach, can be broken down into its book value and the present values of its expected future residual incomes, as illustrated in the formula below.
Residual income is the amount of net income generated in excess of the minimum rate of return. Residual income concepts have been used in a number of contexts, including as a measurement of internal corporate performance whereby a company's management team evaluates the return generated relative to the company's minimum required return. Alternatively, in personal finance, residual income is the level of income that an individual has after the deduction of all personal debts and expenses have been paid.