Index funds provide you with a way to invest in the stock market that is completely passive. For example, if you invest money in an index fund that is based on the S&P 500 Index, you will be invested in the general market, without having to concern yourself with choosing investments, rebalancing your portfolio, or knowing when to sell or buy individual companies. All that will be handled by the fund which will base the fund portfolio on the makeup of the underlying index.
In 2017, I ended up deploying roughly $611,000 into stocks and $604,327 into municipal bonds. The stock allocation should boost dividend income by about $12,500 a year, and the municipal-bond portion should boost income by about $18,000 a year after tax ($26,000 pre-tax). Therefore, total passive income gets an about $38,500 lift, which recovers over half of my $60,000 loss from selling the house.
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.