The first form of residual income, the leftover cash after bills and expenses are paid, is important when a person is growing their savings account or is seeking a loan or financing. When getting a loan, there must be an adequate amount of residual income available to ensure a person has the money to make the loan payments each month. If there is not adequate residual income, financing or loans will not likely be approved.

Lending Club went public in 2014 and is now worth about $1.7B. They advertise P2P lending returns of over 7% for well-diversified portfolios of over 100 notes. I’ve personally been able to achieve a 7.4% annual return over the past two years in a completely passive way by investing in A and AA notes. Others have achieved a 10% annual return through relatively minimum effort.

For those who prefer a more do-it-yourself style but still want their investments to be managed automatically, a robo-advisor like Betterment may be better suited. After completing an initial questionnaire, this program will automatically invest your money based on things like your risk tolerance and time horizon. They’ll even rebalance your portfolio when necessary – all automatically, of course!

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.