text: the company paid $50,000 cash for a capital investment. the company expects the investment? the company paid $50,000 cash for a capital investment. the company expects the investment to generate net cash inflows of $8,400 per year. what is the payback period of this investment? if the cash inflow is only $8,400 a year, they may never pay back the investment. if on the other hand you mean net increase in profit after taxes, about 6 years, still not a good roi.