A different definition of residual income is that this is income derived from passive investments, rather than from a person's active income-generating activities. Examples are interest income, royalty income, rent, and increases in the value of investments held. Individuals typically work throughout their careers in order to build up a sufficient amount of this income to support them during their retirement.

What's crazy is that my book income is more than my SF condo-rental income. Yet I didn't have to come up with $1.2 million of capital (the minimum cost to buy my condo today) to create my book. All I needed to create my book was energy, effort, and creativity. I truly believe that developing your own online product is one of the best ways to make money.

Managerial accounting defines residual income in a corporate setting as the amount of leftover operating profit after all costs of capital used to generate the revenues have been paid. It is also considered the company's net operating income or the amount of profit that exceed its required rate of return. Residual income is normally used to assess the performance of a capital investment, team, department or business unit.