To underwrite a real estate deal, you verify the seller’s reported income and expenses against tax filings, build a financial model around the metrics lenders actually test, pressure-check the assumptions against market and physical evidence, resolve environmental and tax exposure, and submit the package for credit review. The order matters. Skipping the verification step and going straight to the model is how analysts end up defending numbers that were never real to begin with.
Start With Documents You Can Trust
A seller or broker will usually hand over a profit and loss statement covering the prior twelve to twenty-four months. Treat it as a starting point, not gospel. Marketing packages routinely understate expenses or inflate income, so you need independent verification from tax records.
For properties held in partnerships or S corporations, IRS Form 8825 is the document to pull. It reports the rental real estate income and deductible expenses that flowed through to the entity’s tax return.1IRS. Instructions for Form 8825 and Schedule A (12/2025) For individually owned properties, Schedule E on the owner’s personal return does the same job. When the marketing package diverges from what was reported to the IRS, that gap tells you something important about either the accuracy of the operating data or how aggressively the seller has been accounting.
Rent rolls need their own scrutiny. A rent roll shows each unit’s lease terms, current rent, security deposit, and expiration date, but it only captures a moment. Verify it against actual bank deposits or request tenant estoppel certificates, which are signed statements from each tenant confirming the material terms of their lease. If a tenant’s estoppel contradicts the rent roll on rent amount, expiration, or concessions, the seller’s data is unreliable before you’ve run a single calculation.
Round the file out with historical utility bills, insurance declarations, property tax assessments, and title reports showing liens or encumbrances. Then map every line item into a standardized spreadsheet where repairs, insurance, management fees, and smaller recurring costs like landscaping and trash removal each get their own cell. Skipping that mapping step is where expensive errors slip in.
Build the Numbers Lenders Will Test
Once the raw data is organized, the model gets built around a short list of metrics that every lender and equity investor will look at. Each one answers a specific question about the deal.
Net Operating Income and Cap Rate
Net operating income is gross rental income minus all operating expenses, excluding debt payments and capital expenditures. It drives almost every other number in the model. Divide annual NOI by the purchase price to get the capitalization rate. A property generating $150,000 in NOI at a $2 million purchase price has a 7.5% cap rate. Higher cap rates generally signal higher risk or a weaker location; lower cap rates reflect stability and stronger demand. Cap rates are most useful for comparing properties within the same market, not as an absolute measure of quality.
Debt Service Coverage Ratio
DSCR tells a lender whether the property’s income covers the mortgage. Divide NOI by total annual debt service, which includes both principal and interest. Most commercial lenders require a minimum ratio of 1.25, meaning the property must generate at least $1.25 in operating income for every $1.00 of debt payment.2SBA 7(a) Loans. What Is the Required Debt Service Coverage Ratio (DSCR) for SBA 7(a) Loans? If your model shows a ratio below 1.25, you need a lower price, more equity, or a different loan structure.
Cash-on-Cash Return
This measures what your invested dollars earn each year. Divide annual pre-tax cash flow, after all expenses and debt payments, by your total out-of-pocket investment including the down payment and closing costs. Invest $200,000, take $20,000 in annual cash flow, and the cash-on-cash return is 10%. It’s especially useful for comparing deals with different leverage because it isolates the return on committed equity.
Debt Yield
Debt yield has become increasingly important in commercial underwriting because it strips away variables that can mask risk. Divide NOI by the total loan amount. A property with $120,000 in NOI and a $1.2 million loan has a 10% debt yield. Unlike DSCR, debt yield isn’t affected by the interest rate or amortization period, so a borrower can’t improve it by negotiating softer loan terms. Many institutional lenders now set minimum debt yield thresholds alongside coverage requirements, and a yield below 8% to 10% will raise flags at most credit committees.
Break-Even Occupancy
Add operating expenses to annual debt service, then divide by gross potential income at full occupancy. If expenses and debt service total $180,000 and gross potential income is $240,000, break-even occupancy is 75%. Below that, the owner can’t cover expenses and debt. Properties with break-even occupancy above 85% leave almost no room for a downturn.
Loan-to-Value and Loan-to-Cost
Federal banking regulators cap how much a bank can lend relative to a property’s value. Under the interagency guidelines, the maximum LTV for commercial construction is 80%, and for stabilized improved commercial property it drops to 85%.3OCC. Comptrollers Handbook – Commercial Real Estate Lending Raw land is capped at 65%. These are ceilings, not targets, and most lenders underwrite well below them, with 70% to 75% being common for conventional commercial financing. Loan-to-cost applies to construction and value-add projects, where there isn’t yet a stabilized value to appraise. Most construction lenders cap loan-to-cost at 75% of total project costs.
Internal Rate of Return
IRR accounts for the time value of money across the entire holding period. It factors in the initial investment, annual cash flows, and the projected sale price at exit to produce a single annualized percentage. Two deals with identical cash-on-cash returns can look very different over a five- or ten-year hold depending on appreciation, debt paydown, and exit timing. Most institutional equity investors target IRRs between 12% and 20%, depending on risk profile.
Sensitivity Analysis
Every model needs stress testing. A one-percentage-point increase in the mortgage rate can push DSCR below the lender’s minimum and kill the deal. The same goes for vacancy spikes, rent declines, or unexpected operating cost increases. Run pessimistic scenarios to see whether the deal has enough margin to survive real conditions rather than the projections in the offering memorandum. If the numbers only work under ideal assumptions, walk.
Check the Assumptions Against the Market and the Building
A clean model is worthless if the inputs don’t reflect what’s happening outside the spreadsheet.
Comparables and Vacancy
Comparable sales analysis reviews recent transactions for similar properties in the surrounding area. Fannie Mae’s appraisal guidelines call for comparables that have closed within the last twelve months, with preference for the most similar properties by size, condition, and use rather than simply the most recent.4Fannie Mae. B4-1.3-08, Comparable Sales This data establishes whether the asking price aligns with what buyers have actually paid locally.
Vacancy rates are the reality check on income projections. If the submarket averages 8% vacancy and your model assumes 2%, the underwriting is fantasy. Use third-party market reports or CoStar data rather than the seller’s stated vacancy, and build in a vacancy allowance that reflects at least the market average, even if the building is fully occupied today.
Inspections and Capital Reserves
A property inspection identifies deferred maintenance and upcoming capital needs that flow directly into your cash flow projections. If the roof needs replacing within three years at $50,000, that expense goes into the model in year three. Same for HVAC, parking lot resurfacing, plumbing, and electrical.
Beyond specific near-term repairs, add a capital reserve assumption to cover ongoing replacements. How much depends on the property’s type, age, and condition, but buildings deteriorate and the cost of maintaining them belongs in the numbers before you calculate returns.
Zoning
Get a zoning confirmation letter from the local planning office verifying allowed uses, development standards, and any site restrictions. If the property is classified as legal non-conforming, meaning its current use was permitted under prior zoning but wouldn’t be allowed today, a major renovation or rebuild could be restricted to a less profitable use. Pending ordinance changes, overlay districts, and environmental zoning restrictions can all affect exit strategy and long-term value.
Clear the Environmental Exposure Before You Close
Environmental liability is one of the few risks in commercial real estate that can make you personally responsible for cleanup costs you didn’t cause. Under CERCLA, the federal Superfund law, a current property owner can be held liable for contamination left by a previous owner or tenant unless they qualify for the innocent landowner defense.5Office of the Law Revision Counsel. 42 US Code 9601 – Definitions The exposure can dwarf the property’s value.
To qualify for that defense, you must conduct what the statute calls “all appropriate inquiries” before acquiring the property. In practice, that means commissioning a Phase I Environmental Site Assessment from a qualified environmental professional following the ASTM E1527-21 standard. The Phase I reviews historical property use, government environmental records, and includes a physical inspection of the site and adjoining properties to identify recognized environmental conditions.6US EPA. Common Elements and Other Landowner Liability Guidance
Timing matters. A Phase I is considered valid when completed within 180 days before the acquisition date. If it’s older than 180 days but less than a year, certain components — the site inspection, records review, and occupant interviews — must be updated to maintain the liability protection. After closing, the defense also requires you to take reasonable steps to stop any continuing contamination and limit exposure to previously released hazardous substances. If the Phase I flags potential contamination, you’ll typically need a Phase II with soil or groundwater sampling before a lender proceeds.
Model the Tax Consequences Accurately
Tax treatment directly affects the after-tax returns in your underwriting model. Ignore it and your projected yields are wrong.
Depreciation Periods
Federal tax law lets you depreciate the building portion of a real estate investment over a fixed period. Residential rental property depreciates over 27.5 years, commercial property over 39 years.7Office of the Law Revision Counsel. 26 US Code 168 – Accelerated Cost Recovery System Only the building is depreciable; land is not. That annual deduction reduces taxable income without any cash outlay, which is why real estate can show a taxable loss on paper while generating positive cash flow. Your model should reflect the after-tax benefit, not just pre-tax cash flow.
Cost Segregation and Bonus Depreciation
A cost segregation study breaks a building into its components and reclassifies certain items into shorter depreciation categories. Electrical systems, cabinetry, flooring, landscaping, and similar items can qualify for 5-year, 7-year, or 15-year recovery periods rather than the default 27.5 or 39 years.8IRS. Cost Segregation Audit Technique Guide The result is a much larger depreciation deduction in the early years of ownership, which improves after-tax cash flow and can materially change the IRR.
For properties acquired after January 19, 2025, the One Big Beautiful Bill Act permanently restored 100% bonus depreciation on qualifying property, meaning those reclassified short-life components can be fully deducted in the first year.9IRS. Treasury, IRS Issue Guidance on the Additional First Year Depreciation Deduction Amended as Part of the One Big Beautiful Bill This is a major underwriting input. On a $3 million acquisition, a cost segregation study might reclassify $600,000 to $900,000 of components into short-life categories, generating a first-year deduction that shelters substantial income from other sources.
Recapture and 1031 Exchanges
Every dollar of depreciation you claim reduces your cost basis, and the IRS collects on that benefit when you sell. Depreciation taken on real property is taxed at a maximum rate of 25% at sale, higher than the long-term capital gains rate most investors pay on appreciation. Exit projections should account for recapture, because the actual after-tax proceeds can be meaningfully less than the gross profit suggests.
A like-kind exchange under Section 1031 of the tax code lets you defer both the capital gains tax and the depreciation recapture by reinvesting the proceeds into a replacement property. The timelines are strict. You have 45 days from the sale of the original property to identify potential replacements, and the entire exchange must be completed within 180 days total. Neither deadline is extendable. Missing either one triggers full taxation on the gain. If your model assumes a 1031 at exit, build in a realistic view of whether you can actually identify and close on a replacement inside those windows.
Package and Submit the Underwriting
The completed work goes into an investment memorandum that presents the financial metrics, market analysis, physical condition findings, environmental reports, and tax projections in a format the decision-makers can evaluate. For institutional deals, the package goes to a credit committee or investment board for a formal vote. A sloppy or internally inconsistent submission creates doubt about the analyst’s work, even if the underlying deal is sound.
Review periods typically run two to three weeks for most institutional lenders. Expect follow-up questions on vacancy projections, capital expenditure timing, and comparable sales adjustments. Fast responses keep the deal on schedule; delays during review are the single most common reason deals miss their target closing dates.
Approval brings a formal commitment letter with the loan terms and conditions. A denial usually identifies the specific metric or risk that fell outside the institution’s parameters, whether that’s a DSCR below the minimum, environmental concerns from the Phase I, or a price that doesn’t line up with comparables. Knowing which metric failed lets you restructure the deal, renegotiate the price, or bring in additional equity to address the shortfall.