IRR (Internal Rate of Return)  内部收益率

内部收益率法（英文：Internal Rate of Return）是用内部收益率来评价项目投资财务效益的方法。所谓内部收益率，就是使得项目流入资金的现值总额与流出资金的现值总额相等的利率、换言之就是使得净现值(NPV)等于零时的折现率。如果不使用电子计算机，内部收益率要用若干个折现率进行试算，直至找到净现值等于零或接近于零的那个折现率。

简单来说，内部收益率就是使企业投资净现值为零的那个贴现率。它具有DCF法的一部分特征，实务中最为经常被用来代替DCF法。它的基本原理是试图找出一个数值概括出企业投资的特性。内部收益率本身不受资本市场利息率的影响，完全取决于企业的现金流量，反映了企业内部所固有的特性。

但是内部收益率法只能告诉投资者被评估企业值不值得投资，却并不知道值得多少钱投资。而且内部收益率法在面对投资型企业和融资型企业时其判定法则正好相反：对于投资型企业，当内部收益率大于贴现率时，企业适合投资；当内部收益率小于贴现率时，企业不值得投资；融资型企业则不然。

一般而言，对于企业的投资或者并购，投资方不仅想知道目标企业值不值得投资，更希望了解目标企业的整体价值。而内部收益率法对于后者却无法满足，因此，该方法更多的应用于单个项目投资。

The internal rate of return is a metric used in financial analysis to estimate the profitability of potential investments. The internal rate of return is a discount rate that makes the net present value (NPV) of all cash flows equal to zero in a discounted cash flow analysis. IRR calculations rely on the same formula as NPV does. Generally speaking, the higher an internal rate of return, the more desirable an investment is to undertake. IRR is uniform for investments of varying types and, as such, IRR can be used to rank multiple prospective investments or projects on a relatively even basis. In general, when comparing investment options, the investment with the highest IRR would probably be considered the best. 相关例句如下，以加深对该术语的理解：

例句1

In capital planning, one popular scenario for IRR is comparing the profitability of establishing new operations with that of expanding existing ones. For example, an energy company may use IRR in deciding whether to open a new power plant or to renovate and expand a previously existing one. While both projects could add value to the company, it is likely that one will be the more logical decision as prescribed by IRR.

在资本规划中，内部收益率的一个广泛假设是比较建立新业务和扩大现有业务的盈利能力。例如，一家能源公司可能会利用内部收益率来决定是新建一座发电厂，或改造和扩建一座已有的发电厂。虽然这两个项目都可以为公司增加价值，但按照内部收益率的规定，其中一个可能是更符合逻辑的决策。

例句2

The internal rate of return rule is a guideline for evaluating whether to proceed with a project or investment. The IRR rule states that if the internal rate of return on a project or investment is greater than the minimum required rate of return, typically the cost of capital, then the project or investment can be pursued. Conversely, if the IRR on a project or investment is lower than the cost of capital, then the best course of action may be to reject it. Overall, while there are some limitations to IRR, it is an industry standard for analyzing capital budgeting projects.

内部收益率规则是评估是否继续项目或投资的指南。内部收益率规则规定，若一个项目或投资的内部收益率大于最低要求收益率，通常是资本成本，那么该项目或投资可以继续进行。相反，如果一个项目或投资的内部收益率低于资本成本，那么最好的方式就是拒绝它。总体而言，虽然内部收益率有一些限制，但它是分析资本预算项目的行业标准。

内部收益率法的计算步骤：

(1)在计算净现值的基础上，如果净现值是正值，就要采用这个净现值计算中更高的折现率来测算，直到测算的净现值正值近于零。

(2)再继续提高折现率，直到测算出一个净现值为负值。如果负值过大，就降低折现率后再测算到接近于零的负值。

(3)根据接近于零的相邻正负两个净现值的折现率，用线性插值法求得内部收益率。