Residual income valuation (RIV; also, residual income model and residual income method, RIM) is an approach to equity valuation that formally accounts for the cost of equity capital. Here, "residual" means in excess of any opportunity costs measured relative to the book value of shareholders' equity; residual income (RI) is then the income generated by a firm after accounting for the true cost of capital. The approach is largely analogous to the EVA/MVA based approach, with similar logic and advantages. Residual Income valuation has its origins in Edwards & Bell (1961), Peasnell (1982), and Ohlson (1995).
If you’ve ever thought to yourself, “I wish there was a product that did this,” then invent it! Create a product, medical or otherwise, and sell it as a company or get royalties for it. It’s not impossible to figure out, I have many friends who have taken a concept to market. Don’t overlook an invention as a fantastic means of attaining passive income.
Wouldn’t it be nice to earn money while not working? That money is called residual, or recurring, income. It's what can happen after you put a lot of time, effort and sometimes money into a job to continue to get paid for the work months or years after it's done. (Salary jobs are part of linear income. This income is directly related to the number of hours you work. If you work 40 hours, you get paid for 40 hours of work.) Once you set up your business to earn residual income, you continue to make money while doing other things – maybe even starting a new business to generate more residual income!
There is also an idea that we should work to build a passive income asset and then sit on the beach relaxing for the rest of our lives. The truth is that most people would get extremely bored with this scenario and will be eager to find something to do. That’s why the world’s billionaires continue to work… they love what they do and it stopped being about the money a long time ago.