Before understanding the concept and working of residual income along with the examples, it is necessary that we understand the concept of an investment center. Investment center is a division within a business much like a cost center or a profit center. The only difference is that the performance of the manager of the investment center is assessed based on return on investment (ROI) of the division or the Residual income (RI). The use of residual income is usually to assess the performance of a manager of the investment center.

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.