The short answer
Trailing twelve months, or T-12, is an operating statement that reports a property's actual income and expenses for the most recent twelve months, usually month by month, rather than for a calendar year or a forecast. Underwriters use it to see current performance, and one agency multifamily guide tests the latest three months of rental income against the trailing six and twelve months before sizing a loan. Read with the rent roll, it is the fastest check of a replacement property's income inside the 45-day identification period.
At a glance
| Period | The latest twelve full months, rolling forward each month |
|---|---|
| Shows | Actual income, operating expenses and net operating income, not a budget |
| Leaves out | Debt service, income taxes and depreciation, which are not operating expenses |
| Watch for | Cash-basis timing, missing reserves and a recent drop hidden inside a twelve-month total |
The T-12 is an underwriting convention built on the NOI definition.
The Code does not use the term; it comes from lending. The OCC handbook on commercial real estate lending defines operating expenses as the costs of operating and maintaining a property, excluding interest, principal and income taxes, and says underwriting should arrive at an NOI that represents a stabilized estimate. It cautions that cash-basis statements and tax returns can overstate income, for example when a year's property tax was not paid in that year.
The Fannie Mae Multifamily Guide has lenders obtain the prior full-year statement or at least a trailing six months annualized, and compare trailing 3-, 6- and 12-month rental income. If the latest three months fall more than 2% below either longer period, income must be cut to 2% below the lowest of the 1-, 3-, 6- and 12-month figures.
A hypothetical: the calendar-year statement says $500,000, the T-12 says $460,000.
Hypothetical figures: in September you are offered a building with a 2025 operating statement showing $500,000 of net operating income. You ask for the T-12 through August 2026. Insurance renewed at a higher premium in March and two tenants left in June, so the twelve months ending in August show $460,000.
The broker's package priced the building off $500,000. The T-12 shows $40,000 a year less, and the last three months, annualized, are lower still. Rerun your price, loan size and replacement-value math on the lower figure, and run your own numbers with your CPA.
Read the twelve monthly columns, not only the total. A one-off repair, a property tax bill paid in a single month or a lump of back rent collected from one tenant can distort any month, and the agency test above exists because a twelve-month total can hide a decline that began only recently.
It bites when you underwrite on a deadline you cannot move.
Section 1031(a)(3) gives you 45 days to identify and 180 days to close; how the two periods overlap is in 45 days inside 180 days. Ask for the T-12, the rent roll and recent bank statements in the first week a property is on your list, not after you have identified it.
On your own sale, a clean T-12 shortens the buyer's diligence and lowers the risk your closing slips, which is part of the pre-sale checklist. For a DST, expect historical operating results only to the extent the memorandum includes them, and use the DST due diligence checklist to ask for what is missing.
Related questions
Is a T-12 the same as a pro forma?
No. A T-12 reports what happened; a pro forma projects what the seller or sponsor expects. Use the T-12 to test the pro forma's assumptions.
Should a T-12 include a replacement reserve?
Sellers' statements often do not. Underwriters impute one anyway: the OCC handbook includes a replacement reserve in operating expenses whether or not it is funded.
What if the seller only has a tax return?
Use it with care. The OCC handbook notes that cash-basis returns can omit expenses incurred but not paid and can treat capital items differently from an operating statement.
Sources
Checked against these publications on September 30, 2026. Rules and figures change; confirm the current version with your CPA or attorney before you act. This page is general information, not tax or legal advice.