Primary references on this page:
HUD MAP Guide chapter 7: project income, rent rolls, vacancy, and collection loss·
Fannie Mae Multifamily Guide: property income analysisA pro forma is a projection: a spreadsheet view of what a property might earn and cost over a future period, from gross potential rent down through vacancy, operating expenses, NOI, debt service, and cash flow. Every listing brochure has one, and every serious buyer builds their own. The word to hold onto is "projection" — a pro forma is a set of assumptions wearing the costume of a financial statement.
The gap between a seller's pro forma and reality is where deals go wrong. Common tells: market rents applied to units that have never achieved them, a thin vacancy allowance, property taxes at the seller's current assessment rather than your post-sale reassessment, and maintenance numbers with no capital reserve. The antidote is to underwrite from actuals — trailing-twelve-month statements, the real rent roll, real tax and insurance quotes — and treat the pro forma as the hypothesis your due diligence has to confirm.
Build every scenario from named assumptions
A useful pro forma stores the source, effective date, owner, confidence, and sensitivity for every material input. In the illustrative base case, annual GPR is $240,000; 5% vacancy is $12,000; concessions are $3,000; and other income is $4,000, producing $229,000 of effective gross income. Operating expenses are $100,000, so NOI is $129,000. After $84,000 of defined debt service, modeled pre-tax cash flow is $45,000.
HUD and Fannie Mae materials demonstrate income approaches that begin with evidenced rent assumptions and explicitly reduce potential income for vacancy, concessions, or collection effects. Their program rules are not a universal template for every property. The pro forma should identify whether rents come from signed leases, current rent roll, recent comps, asking rents, or an unsupported target, and should keep actual historical results alongside the forecast.
| Line | Downside | Base | Upside |
|---|---|---|---|
| Gross potential rent | $228,000 | $240,000 | $252,000 |
| Vacancy | −$18,240 (8%) | −$12,000 (5%) | −$7,560 (3%) |
| Concessions | −$5,000 | −$3,000 | −$1,000 |
| Other income | +$4,000 | +$4,000 | +$5,000 |
| Effective gross income | $208,760 | $229,000 | $248,440 |
| Operating expenses | −$110,000 | −$100,000 | −$98,000 |
| NOI | $98,760 | $129,000 | $150,440 |
| Debt service | −$90,000 | −$84,000 | −$84,000 |
| Modeled pre-tax cash flow | $8,760 | $45,000 | $66,440 |
Grade evidence and version the forecast
Grade the input rather than the confidence of the person presenting it. A signed lease or current tax bill is direct property evidence. A recent comparable, insurer quote, vendor bid, or executed loan term is external or transaction evidence with a date and scope. A broker estimate or management target is an assumption that should remain visibly weaker. Do not average evidence quality into one score that hides a critical unsupported line.
| Input | Preferred evidence | Refresh or exception trigger |
|---|---|---|
| Rent and loss to lease | Executed leases, rent roll, dated comparable set | Renewal, new comp set, or unit-status change |
| Vacancy and concessions | Property history, current pipeline, market evidence | Material trend or policy change |
| Taxes and insurance | Current bill, reassessment analysis, bound quote | Sale, renewal, reassessment, or coverage change |
| Repairs and CapEx | Trailing ledger, inspection, bids, lifecycle schedule | New inspection or scope change |
| Debt service | Executed terms and payment schedule | Rate reset, refinance, or modification |
Turn forecast error into a controlled feedback loop
Each month, bridge actual to pro forma by price or rate, volume or occupancy, timing, scope, and classification. Do not rewrite the original case to match actuals. Preserve the approved version, publish a separate forecast update, and record why the assumption changed. A favorable maintenance variance can reflect deferred work, while unfavorable taxes can reflect a known reassessment; labels need causes and evidence.
A pro forma supports scenario comparison, capital planning, and diligence questions. It does not guarantee rent, value, financing, tax result, or cash distributions. A buyer still needs title, physical, legal, lease, financial, insurance, and financing diligence, and qualified review where assumptions depend on law, accounting policy, or tax treatment.
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Written and maintained by the Aptoria editorial teamEditorial method reviewed July 28, 2026. Aptoria reviews scope, source fit, examples, limitations, links, and publication gates. This record does not claim attorney, CPA, lender, appraiser, or other independent professional sign-off.
Related terms
Investing metrics
Effective gross income (EGI)
Effective gross income is the property income expected after vacancy and collection loss, plus eligible other property income, before operating expenses.
Investing metrics
Net operating income (NOI)
Net operating income is effective property income minus normalized property operating expenses, before debt service and owner-level income taxes.
Investing metrics
Cash flow
The cash left over each period after all income is collected and all expenses — including the mortgage — are paid.
Investing metrics
Vacancy loss
The rent a property fails to collect because units sit empty, expressed in dollars or as a percentage of gross potential rent.
Investing metrics
CapEx reserve
Cash set aside for predictable, infrequent replacements and major building work rather than routine monthly repairs.
Investing metrics
Gross potential rent (GPR)
The maximum rental income a property could produce with every unit occupied at market rent for the full period.
Accounting & tax
Capital expenditure (CapEx)
Spending on a major improvement that adds value or extends a property's life, recovered over time rather than deducted at once.
Investing metrics
Rental yield
A property's annual rent as a percentage of its price or value — gross yield uses rent alone, net yield subtracts operating costs.
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