`Anthony, nice setup! To your question about the rental mortgages, you haven’t said what interest rate you are paying. As a start, if you are paying more than the risk free rate (Treasury bills) which you probably are, then a true apples to apples comparison would be yes, pay off the mortgage. But, if you are comfortable taking more risk, you have other options to invest in which you *hope* will yield you more over the coming years. You also didn’t say whether the rentals generate net income and if so, how much? What is the implied rate of return on the equity you have invested in them? If you pay the mortgages off, you’ll have even more equity tied up, will the extra net income make that worthwhile? Maybe you should use the money to buy more rentals instead, if purchase opportunities still exist in your town. … this is less of an answer than a framework to analyze the decision, hope it is helpful.`

Thus, the residual income approach is better than the return on investment approach, since it accepts any investment proposal that exceeds the minimum required return on investment. Conversely, the return on investment approach tends to result in the rejection of any project whose projected return is less than the average rate of return of the profit center, even if the projected return is greater than the minimum required rate of return.

**Residual income is calculated as net income less a charge for the cost of capital. The charge is known as the equity charge and is calculated as the value of equity capital multiplied by the cost of equity or the required rate of return on equity. Given the opportunity cost of equity, a company can have positive net income but negative residual income.**