An investment property is an asset purchased with the sole purpose of earning revenue. Income from an investment property can be earned through leasing space within an asset or an eventual sale of the asset. Examples of this include a commercial rental property where business lease office space or an apartment building where tenants rent a home to live in.
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.