The 15 T-12 anomaly detectors

Threshold: Fewer than 12 distinct calendar months in the statement.

A trailing twelve must contain twelve months, and every trailing figure on the listing is struck over the months that are actually there rather than scaled up to twelve. The gap is shown to the seller and carried beside the KPIs; it does not block the listing, because the count is one the system derived from the seller's own file and asking them to restate it in prose proves nothing.

Threshold: Any single month where net operating income is below zero.

Usually a non-recurring event such as a large repair or a one-time tax assessment. Surfaced so buyers can normalize it instead of finding it in diligence. No explanation is demanded: a negative month in a year that carries a roof replacement is ordinary, and requiring an essay about it would be an opinion about the business rather than a check on the document.

Threshold: Total operating expenses below 30% of total income, measured only across months that carry BOTH an expense figure and positive income. Silent below three such months.

Stabilized multifamily typically runs 35-50% of effective gross income. A ratio under 30% usually means missing expense categories rather than exceptional efficiency - which is also why the coverage floor exists: the parser omits lines it cannot read instead of zeroing them, so a ratio struck over one or two readable months would accuse a seller of hiding expenses their statement did in fact print.

Threshold: Any month where operating expenses exceed 3x the median of the months BEFORE it. Prior months only, never later ones, and high side only - there is no low-expense bar.

Typically a roof, HVAC, or insurance claim. Calling it out lets buyers normalize NOI instead of underwriting the accident. Judging a month against what preceded it rather than against the whole year keeps a single genuine spike from raising the bar that is supposed to catch it.

Threshold: Two or more months where effective rent falls more than 10% below the median of the months before it. Needs at least three prior months before any month is judged.

Can indicate concessions burning off, a turnover spike, or rent loss the seller should explain before a buyer prices it as a trend.

Threshold: Economic occupancy - collected rent over gross potential rent, excluding RUBS and other non-rent income - does not RISE in any of the trailing 3 months, and falls by more than 307 basis points end to end. A flat month does not break the run; a total drop smaller than 307bp is not reported.

Buyers assume a decline continues unless the cause is documented: concessions, planned renovation, or a lease-up phase. The 307bp floor exists because a run of three barely-down months is arithmetic, not a trend, and a detector that fires on it teaches sellers to ignore it.

Threshold: Average effective rent in the trailing 3 months runs more than 10% above the prior 9-month average.

The classic dressing-up-the-books pattern: aggressive lease-ups timed to a listing, concession burn-off, or one-time fees. Surfaced next to the figures it moves. It is not treated as proof of anything - a rent increase is evidence of a rent increase - so it is shown rather than gated on.

Threshold: Monthly NOI dispersion at or above 0.4, measured as standard deviation over MEAN ABSOLUTE NOI rather than over the mean.

May reflect lumpy semi-annual taxes and insurance or true volatility. Either way, the 3-month rolling NOI is the honest read, not any single month.

Threshold: Other income above 5% of the statement's own printed TOTAL INCOME, without an itemized breakdown. Exactly 5% does not fire.

Laundry, pet fees, parking, application fees, and RUBS each carry different durability. Buyers should know what is in the bucket before they capitalize it. The denominator is the statement's printed total rather than a subtotal reconstructed from the rent lines, because the two differ by whatever the statement books as an adjustment - on real exports that gap moves the ratio by 38 to 107 basis points, in both directions.

Threshold: Zero line items categorized as property taxes across the period.

Either the chart of accounts is incomplete or taxes are accrued elsewhere. Buyers will model their own underwriting tax figure if none is shown.

Threshold: No insurance expense category in the imported statement.

Buyers run their own insurance quote regardless, but a missing line weakens the disclosure and invites a bigger haircut.

Threshold: No management fees booked in the period.

Acceptable for owner-managed properties; otherwise buyers assume self-management and adjust the proforma for third-party management cost.

Threshold: Property taxes appear in 3 or fewer distinct months instead of monthly accruals.

Valid accounting, but it skews any single-month NOI high or low. Trailing-12 NOI is the number to analyze.

Threshold: Fewer than 4 distinct expense categories in use (industry norm is 6 or more).

Books bucketed too coarsely deny buyers a complete picture of admin, payroll, R&M, utilities, insurance, taxes, and management.

Threshold: Miscellaneous income at 5% or more of total income.

Line-level durability varies: utility reimbursements can disappear while pet rent generally persists. Unlabeled income cannot be underwritten honestly.