Underwriting is the analytical core of commercial real estate — the process of building projections, testing assumptions, and arriving at a defensible value for a property. It is what separates the professionals who make good decisions from those who get burned. This module covers the full underwriting process, the most common mistakes that destroy deals, and how to stress-test your assumptions so the numbers you rely on are actually trustworthy.
Underwriting is the process of building projections about the performance of a real estate acquisition or development opportunity — and then using those projections to assess the risk and value of the deal. In commercial real estate, the price you pay for a property is not based primarily on what similar properties sold for nearby. It is based on the income that property produces — or is projected to produce — and what that income stream is worth to an investor given current market conditions.
This is the fundamental difference between residential and commercial real estate valuation. In residential, you look at comps — what did similar houses sell for? In commercial, you build a pro forma — what will this property earn, what will it cost to operate, what can I sell it for at the end, and what return does that produce at today's asking price?
Value = NOI ÷ Cap Rate — Net Operating Income divided by the capitalization rate. If a property generates $200,000 in NOI and the market cap rate is 5%, the property is worth $4,000,000. If cap rates rise to 6%, the same $200,000 NOI is worth only $3,333,333. A 1% increase in cap rate on a $4M property destroys $666,667 of value without a single dollar of income changing. This is why cap rate assumptions are the highest-stakes numbers in any commercial underwriting.
A pro forma is a projected financial model showing expected income, expenses, debt service, and returns for a property over a defined holding period. It is a planning tool — a structured way to organize your assumptions and see what they produce. A well-built pro forma is the foundation of every acquisition decision, every development budget, and every investor pitch in commercial real estate.
But here is the critical thing to understand: a pro forma is only as reliable as the assumptions that go into it. Garbage assumptions produce garbage projections — and garbage projections produce deals that blow up after closing. Every experienced CRE professional has seen beautiful pro formas attached to disastrous deals. The pro forma was perfect. The assumptions were wrong.
The seller's pro forma — provided in their offering memorandum — shows what the property could earn under optimistic assumptions. It is not what the property actually earns. It is not what you should underwrite to. Your job as a buyer or analyst is to throw away the seller's pro forma and build your own using verified actual numbers. The single most reliable predictor of a bad deal is an investor who underwrote to the seller's projected income rather than the trailing actual income.
| Document | What It Shows | Trust Level |
|---|---|---|
| Seller's Pro Forma | Projected income under optimistic assumptions — often includes income from vacant spaces and assumes rents the property has never actually achieved | 🔴 Do not underwrite to this |
| Rent Roll | Current lease information for each tenant — base rent, lease start and end dates, escalation schedule, reimbursements | 🟡 Verify against actual leases |
| T-12 Financial Statements | Trailing 12 months of actual revenue and expenses — what the property actually collected and spent | 🟢 Best starting point — still verify |
| Tax Returns (2–3 years) | Filed financials that are harder to manipulate — useful for identifying discrepancies vs. T-12 | 🟢 High reliability — cross-reference |
| Actual Leases | The legal contracts — the ultimate source of truth on rent, term, escalations, and tenant obligations | 🟢 Primary source — always review |
Break Into CRE walks through the complete commercial real estate underwriting process — from collecting in-place financials and building operating assumptions, through debt assumptions and sale projections, to arriving at a final valuation based on target returns. Particular attention is paid to the exit cap rate assumption — why it is the highest-stakes number in any underwriting model, and how investors decide where to set it based on interest rate and demand expectations. Published August 2025 — the most current underwriting overview available.
The complete underwriting process from in-place financials through operating assumptions, debt assumptions, exit cap rate projections, and final valuation — with specific focus on why the exit cap rate assumption is the highest-stakes number in any commercial model. Directly reinforces Lesson 1 of this module.
Break Into CRE · YouTube August 2025 · 8 min
Understanding the underwriting process at the conceptual level is not enough — you need to know exactly what data goes into each step and where to get it. The hardest part of underwriting for most beginners is not the math. It is knowing which numbers to trust, which to verify, and which require going directly to a third-party source rather than relying on what the seller provided.
Add basic descriptive information about the property — year built, address, total acreage, leasable square footage, number of units or suites. This step is primarily about making sure you understand what you are actually buying before you start crunching numbers. Many analysts skip past this step — do not. The physical characteristics of a property directly affect assumptions about capital expenditures, marketability, and tenant demand.
Enter current lease data for every tenant — suite square footage, lease start and end dates, scheduled rent escalations, and any expense reimbursement structures. The rent roll gives you a summary. The actual leases are the primary source. Always verify the rent roll against the underlying leases — discrepancies between the two are a yellow flag that warrants further investigation.
Project what happens when in-place leases expire — renewal probability for each tenant, expected downtime between leases if they vacate, market rent for each suite, free rent periods, TI allowances, and leasing commissions. This is one of the hardest parts of any underwriting because it requires genuine market knowledge. Do not guess — call a leasing broker active in the submarket. They know current rents, concession levels, and absorption rates that no database fully captures.
Project ongoing expenses: repairs and maintenance, insurance, property taxes, property management fees, and other operating costs. The seller's T-12 is a useful starting point — but do not accept it uncritically. Three expense line items require independent verification: insurance (get your own quote — rates have increased dramatically in many markets), property taxes (research when and how the property will be reassessed after your purchase — it often resets significantly higher), and property management fees (call a local PM company for market rates).
Estimate the cost and timing of any renovation or value-add work. Add a contingency percentage — typically 10% to 20% on top of your base estimates. Never accept your own rough estimate as a capital budget. Always get a number from an experienced general contractor who has walked the property. Construction costs that blow out are one of the most common ways value-add deals destroy investor returns.
Add loan terms — projected loan amount, interest rate, amortization period, loan term, any interest-only period, and refinance projections if the initial term is shorter than your hold period. You cannot get concrete loan terms before a property is under contract — but a mortgage broker can give you a reliable ballpark before you submit an offer. Underwriting with debt assumptions that are materially off from what you can actually obtain is a common mistake that distorts your projected returns.
Project the sale price by selecting an exit cap rate — the cap rate the next buyer will apply to your last year of NOI. This is the highest-stakes assumption in the model. A conservative exit cap rate assumes cap rates expand from today's levels. An aggressive exit cap rate assumes compression. When interest rates are expected to rise, underwrite cap rates expanding. When rates are expected to fall, underwrite flat or slight compression. Then adjust your purchase price until the projected returns hit your target IRR, equity multiple, or cash-on-cash.
"The exit cap rate assumption can have such a big impact on projected returns on a deal. If interest rates are expected to rise and demand for commercial real estate is expected to fall, investors will typically underwrite cap rates expanding. And if interest rates are expected to fall and demand is expected to rise, investors will typically underwrite cap rates to either stay the same — to be conservative — or even sometimes to compress slightly during the projected hold period."
Break Into CRE walks through the same seven-step underwriting framework in practitioner depth — covering not just what each step involves but exactly where the data comes from for each input. The re-leasing assumptions section is particularly valuable: it covers renewal probabilities, downtime between leases, TI allowances, CoStar, leasing broker relationships, and why this step is the hardest part of any commercial underwriting. Essential viewing for anyone targeting analyst roles or building their first pro forma.
The complete seven-step underwriting process in practitioner depth — covering what goes into each step, where to get the data for each input, and why re-leasing assumptions are the hardest part of any commercial underwriting. Includes a walkthrough of an actual Break Into CRE pro forma model. Directly reinforces Lesson 2 of this module.
Break Into CRE · YouTube August 2023 · 10 min · Evergreen content
Most commercial real estate losses do not come from bad luck or unpredictable market forces. They come from predictable, avoidable underwriting mistakes that experienced investors learn to recognize — and beginners do not. Peter Harris calls them landmines: they are buried in plain sight, invisible to those who do not know to look, and devastating when triggered. Every one of these has destroyed real deals with real investor capital. Learn them before you need them.
The seller's financial statements are prepared to sell the property at the highest possible price. Some sellers keep meticulous records. Others operate on what insiders call "shoebox accounting" — receipts stuffed in a box, numbers reconstructed from memory, income and expenses that are inconsistent, unverifiable, or simply wrong.
Your job as a buyer or analyst is to independently verify every material number before you rely on it. Request tax returns alongside the T-12. Cross-reference rent collected against the actual leases. Request utility bills, insurance invoices, and property tax statements directly. If numbers cannot be verified, assume the worst-case scenario — not the presented scenario. Deals that close on unverified seller numbers frequently disappoint after closing.
A pro forma is a projection. It shows what a seller believes or hopes the property could earn under favorable conditions. The offering memorandum pro forma almost always includes income from currently vacant spaces leased at optimistic market rents, assumes rent bumps that tenants may not accept, and excludes expenses the seller is not currently incurring but you will be.
Always underwrite to actual trailing income — what the property has actually collected over the last 12 months — not projected pro forma income. Value a property on its actual performance. Then build a separate model showing what the property could earn if your value-add business plan succeeds. Use that model to calculate upside — not to justify your purchase price.
When you have spent months finding a deal and competing against other buyers, the pressure to win can override the discipline to walk away. Sellers and their brokers know this — and some create artificial urgency specifically to trigger it. Auction-style bidding processes, manufactured best-and-final deadlines, and hints of competing offers are all designed to get you to move faster and think less carefully than you should.
Peter Harris puts it simply: when emotion goes up, intelligence goes down. The most dangerous moment in any deal is when you want it so badly that you start finding reasons to ignore the problems rather than finding reasons to confirm the opportunity. Establish your maximum price before you start competing — and do not exceed it regardless of what competing bids are doing.
Three expense categories are consistently underestimated by inexperienced buyers — and consistently cause post-closing surprises that destroy projected returns.
Property taxes: In many jurisdictions, a property sale triggers a reassessment at the new purchase price. The seller was paying taxes on a value from years ago. You will pay taxes on what you just paid — which may be dramatically higher. Research the reassessment rules for your specific jurisdiction before closing.
Insurance: Commercial insurance premiums have increased significantly in many markets since 2020 — particularly in coastal states, fire-prone areas, and any market where carriers have exited. Never assume your insurance cost will match the seller's. Get your own quote before you close.
Capital reserves: Every property has deferred maintenance, aging systems, and components that will need replacement. A roof, HVAC system, elevator, or parking lot that is ten years old is a capital expense that is coming. Build reserves into your model based on realistic replacement schedules — not on the hope that everything will hold until you sell.
The listing broker represents the seller. Their fiduciary duty runs to the seller — not to you. They may be knowledgeable, professional, and genuinely helpful. They are also motivated to close the deal at the highest possible price. Any information, analysis, or market data provided by the listing broker should be treated as a starting point for your own independent research — not as a conclusion you can rely on.
This does not mean listing brokers are dishonest. Most are not. It means their information is filtered through a perspective that is inherently different from yours. Build your own market analysis. Talk to tenant rep brokers who have no interest in the deal closing. Talk to property managers about operating costs. Talk to lenders about what the property will actually finance for. The listing broker's job is to sell the property. Your job is to buy it at a price that makes sense.
A pro forma built on base-case assumptions shows you what happens if everything goes as planned. Professional underwriters do not stop there — they stress-test. They ask: what happens if my best tenant does not renew? What if it takes longer to lease the vacant space? What if interest rates rise at refinance? What if cap rates expand at exit? What if construction costs go over budget? A deal that only works if everything goes right is not a good deal. A deal that still produces acceptable returns under a range of adverse scenarios is.
Your best honest projection of what will happen if you execute your business plan as intended. Current tenants mostly renew. Vacancies lease at market rates on expected timelines. Expenses match your research. Debt terms are as quoted. Exit cap rate is flat to current going-in cap rate.
Vacancy 10–15% higher than base case. Key tenant does not renew — space stays dark for 6–12 months. Rent growth flat rather than projected. Insurance and taxes 15% higher than expected. Construction costs 15% over budget. Exit cap rate 50–75 basis points wider than going-in cap rate.
Two major tenants vacate simultaneously. Leasing market softens — 18–24 months to re-lease. Operating costs spike 20%. Interest rates rise 150 basis points at refinance. Exit cap rate expands 100 basis points. Construction blows 25% over budget. Can you service the debt and stay solvent?
The question is not "will this happen" but "if it does, what do I lose?" What is the minimum value the property produces in a genuine distress scenario? What is your loan covenant exposure? Can you hold through a downturn or are you forced to sell at the worst moment? Know your absolute floor before you close.
| Metric | What It Measures | How It Works | Typical Target |
|---|---|---|---|
| IRR (Internal Rate of Return) | Total return over time — accounts for when cash flows occur | The annualized return that makes NPV of all cash flows zero. Earlier cash flows increase IRR; later cash flows reduce it. | 10–20%+ depending on risk profile |
| Equity Multiple | Total dollars returned per dollar invested — regardless of time | Total distributions ÷ total equity invested. A 2.0x means you doubled your money. Does not account for how long it took. | 1.5x–2.5x+ over hold period |
| Cash-on-Cash Return | Annual cash return as a % of equity invested | Annual pre-tax cash flow ÷ total equity invested. Year-by-year measure of how much cash the investment returns annually before the sale. | 6–10%+ depending on leverage |
| Cap Rate (Going-In) | Initial yield on total purchase price | Year 1 NOI ÷ purchase price. Higher cap rates mean more income relative to price — generally indicates more risk or less desirable market. | Market dependent — 4–8% |
| DSCR (Debt Service Coverage Ratio) | How much income cushion exists above debt payments | NOI ÷ Annual Debt Service. Lenders typically require 1.20–1.25x minimum. Below 1.0x means the property cannot cover its debt payments from operations. | 1.20–1.35x minimum |
The most dangerous thing you can do in commercial real estate underwriting is assume that an aggressive exit cap rate will bail out a deal with weak in-place fundamentals. A property with shaky tenants, below-market NOI, and uncertain expenses cannot be made into a good deal by projecting a cap rate compression that assumes market conditions you cannot control. Exit cap rate assumptions should be conservative — usually flat to current or slightly expanded. If a deal only works with a compressed exit cap rate, the deal does not work.
This module taught you how underwriting works — the logic, the process, the data sources, and the judgment required. What it did not teach is how to build the actual models in software. Two tools matter most in professional CRE:
Excel: The universal tool for pro forma modeling across all property types. Every analyst role will require it. The free Break Into CRE Real Estate Financial Modeling Crash Course is the best starting point available — free, structured, and taught by the same voice you have heard throughout this module.
ARGUS Enterprise: The industry-standard software used by institutional firms for underwriting office, retail, and industrial properties with complex lease structures. If you are targeting analyst roles at major firms like CBRE, JLL, Cushman & Wakefield, or top private equity funds, expect to be asked about ARGUS in your first interview. The Altus Group ARGUS University offers training directly from the software maker.
Break Into CRE — Commercial Real Estate Fee Structures Explained
The four most common partnership-level fee structures in CRE syndications and funds — acquisition fee (0.5–2% of purchase price), asset management fee (1–2% of gross revenue or 0.5–1.5% of equity), construction management fee (4–8% of construction costs), and disposition fee (0.5–2% of sale proceeds). Essential for understanding how GP fees affect LP returns — and how to evaluate whether a deal's fee structure is fair before investing.
Peter Harris — Commercial Property Advisors: 3-Step Multifamily Analysis
Peter Harris walks through his three-step framework for quickly evaluating a multifamily deal — estimating NOI, applying a cap rate to get value, and checking whether the numbers work at the asking price. A fast practical tool for initial deal screening before committing to a full underwriting. Already used in Core Foundation Module 5 but worth revisiting with the deeper underwriting context from this module.
Adventures in CRE — Letter of Intent Walkthrough
Understanding how the LOI captures the key economic terms of a deal — purchase price, earnest money, due diligence period, closing timeline — matters directly for underwriting since the due diligence period is when you verify all your assumptions. The LOI sets the window you have to complete that verification.
5 questions — click your answer, then check all at once.
1. A commercial property generates $180,000 in NOI. It is listed at a 5% cap rate. Interest rates then rise, pushing market cap rates to 6.5%. What happens to the property's value?
2. A seller provides T-12 financials showing $40,000 in annual insurance expense. You get your own insurance quote and it comes back at $67,000. What should you do?
3. The seller's offering memorandum shows a pro forma NOI of $420,000 — including $80,000 of income from currently vacant spaces leased at "market rate." The trailing actual NOI from T-12 statements is $340,000. What NOI should be used to determine your offer price?
4. A property's NOI is $300,000 and annual debt service is $260,000. What is the DSCR and should a conservative lender approve this loan?
5. An investor models a commercial deal and it only produces an acceptable IRR if the exit cap rate compresses 75 basis points from the going-in cap rate. What should the investor conclude?