Return on Investment . When an accountant reports income in each year of a multi-year project , the stream of cash flows must be broken up into annual rates of return for those years. The return on investment (ROI) as used by accountants usually means the accountant’s rate of return for each year of the project duration based on the ratio of the income (revenue less depreciation) for each year and the undercoated asset value (investment) for that same year. Hence, the ROI is different from year to year, with a very low value at the early and a high value in the later year of the project.