The Number Nobody Stress Tests
Every CRE deal has dozens of assumptions. Rent growth, vacancy, expenses, interest rate, hold period. Most investors spend their diligence energy on the operating assumptions: will rents grow 2% or 3%? Will vacancy run 5% or 7%?
Meanwhile, the assumption that actually controls the deal sits quietly at the bottom of the model. The exit cap rate.
In a standard 10-year DCF, the terminal sale (reversion) represents 60% to 75% of total property value. That means the exit cap rate assumption carries more weight than every operating assumption combined. A 50 basis point error in exit cap rate does more damage to your returns than a full percentage point error in rent growth.
Most pro formas show a single exit cap rate. No sensitivity, no scenarios, no discussion of what happens if the assumption is wrong. That is the biggest blind spot in CRE underwriting.
The Math: Why 50 Basis Points Matters So Much
Take a property with projected Year 11 NOI of $1,200,000. Here is what happens to the terminal value as the exit cap rate moves:
| Exit Cap Rate | Terminal Value | Change from Base |
|---|---|---|
| 5.0% | $24,000,000 | +$5.5M |
| 5.5% | $21,818,000 | +$3.4M |
| 6.0% | $20,000,000 | +$1.5M |
| 6.5% (base) | $18,462,000 | — |
| 7.0% | $17,143,000 | -$1.3M |
| 7.5% | $16,000,000 | -$2.5M |
| 8.0% | $15,000,000 | -$3.5M |
A 100 basis point expansion (6.5% to 7.5%) reduces the terminal value by $2.5 million. On a deal where total equity invested is $4 million, that is 62% of your entire equity position evaporating from a single assumption.
Now translate that to IRR. On a $12M purchase with $4M equity, annual cash flows of $200K, and a 10-year hold:
| Exit Cap Rate | Terminal Value | IRR |
|---|---|---|
| 5.5% | $21,818,000 | 18.2% |
| 6.0% | $20,000,000 | 15.6% |
| 6.5% | $18,462,000 | 13.1% |
| 7.0% | $17,143,000 | 10.8% |
| 7.5% | $16,000,000 | 8.7% |
The IRR swings from 18.2% to 8.7% based entirely on exit cap rate. That is a 950 basis point range. Meanwhile, a full percentage point change in annual rent growth (2% vs. 3%) might move the IRR by 150 to 200 basis points. The exit cap assumption is 4 to 5 times more sensitive than the rent growth assumption.
The Cap Compression Trap
When investors underwrite exit cap rate equal to or below the going-in cap rate, they are making a bet that cap rates will compress during their hold period. This is not an operating assumption. It is a market bet.
Cap rate compression means the market will pay more per dollar of income at exit than you paid at entry. For that to happen, one of two things must be true: either risk premiums decline (investors become more willing to accept lower returns) or growth expectations increase (the market believes NOI will grow faster in the future).
Between 2010 and 2021, cap compression was the dominant driver of CRE returns. Low interest rates, abundant capital, and strong rent growth all pushed cap rates down. Investors got addicted to the pattern. Many underwrote exit at a flat or compressed cap, treated the assumption as "conservative," and never tested the alternative.
Then rates rose 500 basis points in 18 months. NBER research documented 14% of all CRE loans in negative equity by 2023. The deals that relied on cap compression for their returns got destroyed.
The institutional standard: exit cap rate 25 to 50 basis points above going-in cap rate. Buildings age during the hold period. Newer, more competitive properties get built. The probability of cap expansion over a 10-year hold is higher than compression, because the building is 10 years older and the market has had time to cycle.
How to Think About Exit Cap Rate
The Gordon Growth Model gives you the framework: Cap Rate = r - g, where r is the required total return and g is expected NOI growth.
At exit, the buyer is making their own r and g assessment. Ask yourself: what will the buyer see when they evaluate this building in 10 years?
The building is 10 years older. Functional depreciation has occurred. NCREIF data shows NOI growth for aging buildings runs 200 basis points below inflation. A buyer in Year 10 is looking at a building that has depreciated relative to newer competition.
The market may have cycled. If you buy during expansion and sell during contraction, cap rates will be higher at exit. If you buy during contraction and sell during expansion, the reverse. You do not control which cycle phase you exit into.
Interest rates may differ. The spread to Treasury tends to revert to its ~200 basis point historical mean. If you bought when spreads were tight (below 150 bps), there is room for expansion. If you bought when spreads were wide (above 300 bps), there may be room for compression.
The mental model: your exit cap rate should reflect the building you will have in 10 years, not the building you have today. If you plan to renovate and reposition, the exit cap may justifiably be near or below going-in. If you are buying a stabilized asset and holding, the exit cap should be higher.
The Sensitivity Matrix: Your Decision Tool
The 5x5 sensitivity matrix is the institutional standard for stress testing exit cap rate against other key assumptions. Here is how to build one.
Pick your two most sensitive variables. Usually exit cap rate and rent growth. Build a grid:
| Rent -1% | Rent 0% | Rent 1% | Rent 2% | Rent 3% | |
|---|---|---|---|---|---|
| Exit Cap 5.5% | 14.1% | 15.2% | 16.4% | 17.5% | 18.7% |
| Exit Cap 6.0% | 11.8% | 12.9% | 14.0% | 15.1% | 16.2% |
| Exit Cap 6.5% | 9.7% | 10.7% | 11.8% | 12.8% | 13.9% |
| Exit Cap 7.0% | 7.8% | 8.8% | 9.8% | 10.8% | 11.8% |
| Exit Cap 7.5% | 6.1% | 7.0% | 7.9% | 8.9% | 9.9% |
Note: Illustrative IRRs on a $12M deal, 70% LTV, 7% rate, 30-year amortization, 10-year hold.
Now count the cells that meet your target IRR. If your threshold is 10%:
- 17 of 25 cells pass (68%): strong deal. It works even if rent growth disappoints and exit cap expands.
- 12 of 25 cells pass (48%): decent deal, but needs things to go right.
- 7 of 25 cells pass (28%): fragile deal. Only works with cap compression and strong rent growth. Walk away unless you have a specific, documented thesis for why those conditions will hold.
The count tells you how much margin of safety the deal has. A deal where 20 of 25 cells work at your target is fundamentally different from one where 8 of 25 work, even if both have the same base-case IRR.
The Equity Multiple Check
IRR has a weakness: it is sensitive to timing. A 20% IRR on a 2-year flip with a 1.3x equity multiple means you only made 30% total. The equity multiple tells you total value creation regardless of timing.
Run the sensitivity matrix on equity multiple too. If a deal shows a 12% IRR but only a 1.4x equity multiple on a 10-year hold, total value creation is modest. The 12% looks acceptable until you realize 40% total gain over a decade is barely keeping pace with inflation after taxes.
For a 10-year hold, institutional investors typically target a 2.0x to 2.5x equity multiple alongside a 12% to 15% IRR. If the equity multiple falls below 1.5x in your base case, the deal may not be worth the illiquidity.
The Decision Framework
Before you accept any exit cap rate assumption:
What is the going-in cap rate? Your exit cap should be at least 25 to 50 bps higher unless you have a specific thesis for compression (major renovation, supply constraints, rate decline).
What is the current spread to Treasury? If the spread is already below 150 bps, cap expansion is more likely than compression. If it is above 300 bps, the opposite may be true.
How many cells pass in your sensitivity matrix? If fewer than half the cells at your target IRR work, the deal is fragile.
What does the equity multiple look like in the stress case? If exit cap expands 100 bps, do you still double your money?
Are you betting on operations or the market? If your returns depend primarily on cap compression, you are speculating. If they depend primarily on rent growth and expense control, you are investing.
Where to Go Next
- Understanding what cap rate means. Read What Is a Good Cap Rate for the full decomposition of cap rate into required return and growth expectations.
- Auditing the NOI that feeds your exit value. Read How to Read a Pro Forma for the line-by-line framework.
- The full underwriting process. Read How to Underwrite a Multifamily Deal for the institutional 6-step framework including sensitivity analysis.
- Common exit cap mistakes. Read 8 Underwriting Mistakes, specifically Error #8 on flat exit cap assumptions.
Sources
- Geltner et al., "Commercial Real Estate Analysis and Investments," 2nd Ed. (2007), Chapters 10-11: DCF and Cash Flow Proformas
- NCREIF Property Index, 1978-2004 (NOI growth and terminal value data)
- CBRE U.S. Cap Rate Survey, H2 2025
- NBER Working Paper 31970, "Monetary Tightening, Commercial Real Estate Distress, and US Bank Fragility" (2023)
- CFA Institute, "The Interplay Between Cap Rates and Interest Rates" (2024)