ROI Return On Investment 投资回报率
A performance measure used to evaluate the efficiency of an investment or to compare the efficiency of a number of different investments. ROI measures the amount of return on an investment relative to the investment's cost.
投资回报率指通过投资而应返回的价值,即企业从一项投资活动中得到的经济回报。它涵盖了企业的获利目标。利润和投入经营所必备的财产相关,因为管理人员必须通过投资和现有财产获得利润。
ROI = (Gains – Cost)/Cost
NPV Net Present Value 净现值
Net Present Value is the difference between the present value of cash inflows and the present value of cash outflows over a period of time.
净现值是一项投资所产生的未来现金流的折现值与项目投资成本之间的差值。
Ct = net cash inflow during the period t 在t期间的净现金流入
Co = total initial investment costs 总初始投资成本
r = discount rate 贴现率
t = number of time periods 时间周期
投资规则:NPV>0,可以投资;NPV<0,不应该投资。
但实际操作中,很少看到NPV,有两个原因:
1) 由于NPV是一个绝对的数值,容易忽略了投入本金的规模,也就是我们经常说的效益和产出比。
2)人们更习惯知道某个项目的收益率,这样可以很方便的与别的项目比较。