The Internal Rate of Return (IRR) is the discount rate that makes the Net Present Value (NPV) of all cash flows from a particular project equal to zero. In other words, it is the expected rate of return that a project is anticipated to yield.
Calculation:
IRR is typically found through trial and error or interpolation, by solving for 'r' in the NPV equation where NPV = 0:
0 = Σ [Cash Flow_t / (1 + IRR)^t] - Initial Investment
Decision Rule:
- Accept projects where IRR > Cost of Capital.
- Reject projects where IRR < Cost of Capital.
Advantages:
- Considers Time Value of Money: It discounts all cash flows, accounting for their timing.
- Considers All Cash Flows: It takes into account all cash flows over the project's entire life.
- Easy to Understand: Expressed as a percentage, which is intuitive for managers to compare with the cost of capital.
Disadvantages:
- Multiple IRRs: For projects with unconventional cash flow patterns (e.g., alternating signs), there can be multiple IRRs, making the decision ambiguous.
- Reinvestment Rate Assumption: Implicitly assumes that intermediate cash flows are reinvested at the IRR itself, which may not be realistic or achievable.
- Conflicting Rankings with NPV: Can give conflicting rankings compared to NPV for mutually exclusive projects, especially when project sizes or cash flow patterns differ significantly.
- Difficulty in Calculation: Requires complex iterative calculations, often relying on financial calculators or software.