In 2012, even I wrote a 150-page eBook about severance package negotiations that still regularly sells about ~35 copies a month at $85 each (2nd edition for 2017) without any effort. In order to generate $2,975 a month or $35,700 a year in passive income as I do now, I would need to invest $892,500 in something that generates a 4% yield! To earn $10,000 a year in passive income would therefore need roughly $250,000 in capital.
People who are making a living with residual income typically create a full-time income from more than once source. In this way, if one of their income streams gets cut off, they will manage their others and perhaps even branch out a bit more. A passive recurring income stream doesn’t have to be isolated to one venue. Because it nearly runs itself, you are provided the freedom to test and evaluate other sources of recurring passive 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.