You are also free to choose a fund that is based on any index that you want. For example, there are index funds set up for just about every market sector there is — energy, precious metals, banking, emerging markets — you name it. All you have to do is decide that you want to participate, then contribute money and sit back and relax. Your stock portfolio will then be on automatic pilot.
You don't have to be Paul McCartney to rack up residuals. You might own properties that you rent out even though you're not a Realtor. Maybe a blog you started took off, and while you no longer work there, you still collect part of the profits. Or perhaps you're a serial entrepreneur who creates companies and moves on. You, too, are earning residual income.
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.