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IRR vs MIRR: The Duel of Metrics in CRE Investment

Two metrics in the ring
IRR vs MIRR Showdown: The Playful Battle of Investment Metrics in Commercial Real Estate

In the high-stakes world of commercial real estate investment, two acronyms often steal the spotlight in performance metrics: IRR (Internal Rate of Return) and MIRR (Modified Internal Rate of Return). While they may sound like distant cousins at a family reunion, understanding their differences is crucial for astute investors and industry professionals. Let’s go ringside and discover the nuances of these financial heavyweights.

IRR: The Traditional Contender

Internal Rate of Return is the OG (Original Gangster) of investment metrics, a tried and tested formula that has been sizing up investments since, well, forever. It calculates the annual growth rate of an investment over its lifetime. In technical terms, it is the discount rate that makes the Net Present Value (NPV) equal to 0, but you have to understand NPV first for this to make sense. In practical terms it is effectively answering the question: "What is the rate of return I'm getting on this investment?" Another key to understanding IRR is in the first word, "internal," meaning that once the cashflows exit the investment, they are no longer earning that return. This is important to understand as we define MIRR.


  • Time-Value of Money: IRR respects the golden rule of finance – a dollar today is worth more than a dollar tomorrow.

  • Comparative Ease: It provides a simple percentage, making it easy to compare different investments.


  • Overly Optimistic: IRRs can be manipulated by increasing the cashflows and reversion (sale proceeds) to make an investment look better than it is.

  • Single-Scenario Mindset: It doesn’t consider alternate scenarios or different market conditions.

MIRR: The Modern Maverick

So what happens when those cashflows leave the investment? Enter Modified Internal Rate of Return, the sophisticated cousin who brings a touch of realism to the family. MIRR tweaks the IRR formula by incorporating the costs of investment and the more realistic reinvestment rates. In commercial real estate, we hope to get cashflows from operations which are rarely reinvested back into the real estate. Once the cash hits our bank account, it is no longer receiving that sweet, lovely IRR compounding. But that doesn't mean we still can't calculate it. Let's look at a real world example:

An investment example

In this investment, we had a 9% discount rate and an 8% reinvestment rate. The IRR of the investment ends up being a bit over 30%, but the MIRR has a lower yield. Why is that? Well remember in the beginning I told you once the cashflows leave the investment, they are no longer getting that IRR rate. Our reinvestment rate was lower than our discount rate, meaning once those cashflows left the investment, they were now being reinvested at a lower rate of return.


  • Realistic Reinvestment Rate: It uses a more conservative approach, accounting for the fact that reinvestment rates are often lower than the original IRR.

  • Addresses Multiple Scenarios: MIRR can factor in varying financing and reinvestment rates, offering a broader picture.


  • Complexity: With added realism comes added complexity, making MIRR a bit harder to calculate and understand.

  • Less Known: It’s not as widely used or understood as IRR, which can be a downside in communication.

In the Ring: IRR vs MIRR

So, when these two metrics step into the ring, who wins? The answer is, as with many things in commercial real estate investment, it depends.

  • For simplicity and quick comparisons, IRR is your go-to. It gives you a fast, albeit sometimes overly optimistic, snapshot.

  • For a more nuanced and realistic evaluation, MIRR takes the crown. It provides a perspective that considers real-world constraints on reinvestment.

Conclusion: The Right Tool for the Right Job

In the end, both IRR and MIRR have their rightful place in the commercial real estate investment toolbox. The savvy investor uses IRR for its simplicity and MIRR for its depth, creating a balanced view of their investment’s performance. Remember, in the world of commercial real estate investment, knowledge of your tools isn’t just power – it’s profit.


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