The advantages and disadvantages of the internal rate of return are important to understand before applying this technique to specific projects. There must be a proper analysis conducted and an interpretation of most projects by this well-known technique of evaluation and selection of investment projects. This technique has certain limitations in analyzing certain special kinds of projects, such as mutually exclusive projects, an unconventional set of cash flows, different project lives, etc.

Table of Contents

- 1 ADVANTAGES OF THE INTERNAL RATE OF RETURN
- 2 DISADVANTAGES OF INTERNAL RATE OF RETURN
- 2.1 Economies of Scale Ignored
- 2.2 Impractical Implicit Assumption of Reinvestment Rate
- 2.3 Dependent or Contingent Projects
- 2.4 Mutually Exclusive Projects
- 2.5 Different Terms of Projects
- 2.6 A mix of Positive and Negative Future Cash Flows
- 2.7 Calculation of IRR is not possible
- 2.8 The objective of wealth maximization

## ADVANTAGES OF THE INTERNAL RATE OF RETURN

The various advantages of the internal rate of return method of evaluating investment projects are as follows:

### Time Value of Money

The first and the most important thing is that the internal rate of return considers the time value of money when evaluating a project. This is a huge downfall in the accounting rate of return, an average rate of return and Pay Back period. One can measure IRR by calculating the interest rate at which the PV of future cash flows is equal to the capital investment required.

### Simplicity

The most attractive thing about this method is that it is very simple to interpret after the IRR is calculated. If the IRR exceeds the cost of capital, then accept the project, but not otherwise. This is very easy to visualize for managers, which is why it’s preferable unless they come across occasional outstanding situations, like mutually exclusive projects, etc.

### Hurdle Rate / Required Rate of Return Is Not Required

The hurdle rate is a difficult and subjective thing to decide. In IRR, there is no requirement for finding out the IRR hurdle rate or the required rate of return. It is not dependent on the hurdle rate, so the risk of a wrong determination of the hurdle rate is diminished. If one calculates the net present value, profitability index, etc., that will require the hurdle rate.

### Required Rate of Return is a Rough Estimate

Managers make a rough estimate of the required rate of return, but the method of IRR is not completely based on the required rate of return. Once we come up to the IRR, we can compare it with the hurdle rate. If the IRR is far from the estimated required rate of return, the manager can safely make the decision on either side. Also, he can maintain room for estimation errors.

## DISADVANTAGES OF INTERNAL RATE OF RETURN

The method of internal rate of return does not prove very fruitful under some special types of conditions, which are discussed below:

### Economies of Scale Ignored

One pitfall in the use of the IRR method is that it ignores the actual dollar value of benefits. One should always prefer a project value of $1,000,000 with an 18% rate of return over a project value of $10,000 with a 50% rate of return. There is no need for in-depth analysis; we can clearly see that the dollar benefit of the former project is $180,000, whereas the latter project’s dollar benefit is only $5,000. There is no comparison as to which is more worthwhile. The IRR method will rank the latter project—with a much lower dollar benefit—first, simply because the IRR of 50% is higher than 18%.

### Impractical Implicit Assumption of Reinvestment Rate

While analyzing a project with the IRR method, it implicitly assumes the reinvestment of the positive future cash flows at IRR for the remaining time period of the project. If a project has a low IRR, it will assume reinvestment at a low rate of return; on the contrary, if the other project has a very high IRR, it will assume a reinvestment rate at the very high rate of return. This situation is not practically valid. When you receive those cash flows, having the same level of investment opportunity is rarely possible. In addition to that, making the assumption that at one point in time, one company will have more than one reinvestment rate, is simply not possible. If a company has more than one reinvestment rate opportunity, then it will invest at a higher rate.

### Dependent or Contingent Projects

Many times, finance managers come across a situation when the project under evaluation creates a compulsion of investing in other projects. For example, if you invest in a big transporting vehicle, you will also need to arrange a place for parking it. Such projects are called dependent or contingent projects and must be considered by the manager. IRR may permit the buying of the vehicle, but if the total proposed benefits are wiped off by having to arrange the parking space, there’s no point in investing.

### Mutually Exclusive Projects

Sometimes investors come across mutually exclusive projects, which means that if one is acceptable, then the other is not. Building a hotel or a commercial complex on a particular plot of land is an example of a mutually exclusive project. In such situations, knowing whether they are worth investing in is not enough. The challenge is to know which investment is the best. The IRR method will give a percentage interpretation value, but that is not enough. This is connected to the first disadvantage of economies of scale, which the IRR ignores.

### Different Terms of Projects

Consider two projects with different project durations. One ends after 2 years and the other ends after 5 years. The first project has an additional point of reinvesting the money, which is unlocked at the end of the 2^{nd} year for another 3 years until the other project ends. This point is not considered by the IRR method.

### A mix of Positive and Negative Future Cash Flows

When a project has some negative cash flow between other positive cash flows, the equation of the IRR method is satisfied with more than one rate of return, i.e., it reaches the trap of Multiple IRR. In the case of multiple IRR situations, it’s possible to make a decision with IRR, but we should know that what is NPV at one cost of capital at least.

For example, the IRR for a project is 10% and 30%, and @ 5% NPV is positive, then Project will be accepted if the cost of capital is less than 10% or more than 30%. If the cost of capital falls between 10% and 30%, a project will not be accepted. If the NPV is negative @ 5%, then the decision making would be reversed. So, in such a case, the decision becomes dependent on NPV, which becomes more complicated. It is very rare that such a situation arises, and is mostly found in agency deposits or other similar businesses.

### Calculation of IRR is not possible

If later cash inflows are not sufficient to cover the initial investment, in that case, IRR cannot be found. IRR is then a discounted rate at which the Present Value of Cash Inflow equals the Investment or Present value cash outflow.

### The objective of wealth maximization

Importantly, when there is a conflict in the ranking of mutually exclusive projects between net present value (NPV) and IRR, at that time, NPV criteria supersede IRR criteria because NPV criteria exactly measure the amount by which the value of the firm will increase. The objective of Financial Management in terms of wealth maximization is met, to which extent it can be measured by NPV. IRR will only be able to decide whether a project is worth accepting or not, but what increase in wealth will occur cannot be measured by IRR.

Last updated on : August 17th, 2019
Although the IRR has many problems, the IRR does not assume cash inflows will be reinvested at the IRR rate. Google:

Reinvestment assumption fallacy

for the academic articles that show this.

Good blog!!!

Nice one Mr. Sanjay, more strength to your elbow.

Pls am interested if my assistant is been needed.

Thanks.