Building a Defensible Income Approach for a Commercial Property Tax Appeal

Why boards give the income approach the most weight

Investors price office buildings, shopping centers, warehouses and apartments on income, and assessment law points the same way. Texas Tax Code §23.012 tells the chief appraiser, when the income method is the most appropriate approach, to estimate gross income from comparable rental data, estimate expenses from comparable operating expense data, and derive capitalization or discount rates from comparable data. In Cook County, Board of Review Rule 19 requires any appraisal submitted for income-producing property to include an income approach, or a written explanation of why it was omitted.

The stakes justify the work. Property taxes run 30% to 45% of total commercial operating expenses (IPT / BOMA Experience Exchange Report), and IPT reports that commercial appeals succeed 60% to 75% of the time when they are backed by income, sales and uniformity evidence. The income approach is usually the anchor of that package, but only if each line ties back to the market.

That last point is where owners lose. The Illinois Property Tax Appeal Board has declined to give weight to actual income and expense figures that were not shown to reflect market rent, vacancy and expenses. Actual numbers are evidence. Market-supported numbers are value.

Start from market rent, not the lease you signed

Many jurisdictions, by statute or case law, value the fee simple interest: the property as if available for lease at market terms, rather than the leased fee interest created by today's leases. That makes the rent roll evidence of market rent, not the answer. A lease signed at the top of the last cycle may sit well above achievable rent, and a long-term anchor lease signed a decade ago may sit well below it.

Build market rent from three sources and reconcile them: recent leasing in the subject (new signings and renewals in the last 12 to 18 months), lease comparables from competing buildings in the submarket, and asking rents adjusted for the concessions actually being granted. Convert free rent and above-standard tenant improvement packages into an effective rent. A $28.00 face rent with eight months free on a seven-year term averages about $25.33 over the term, and that is the number a buyer underwrites.

Then apply the result consistently. If in-place rents are above market because of a credit tenant or a thin tenant improvement allowance, mark them to market. If they are below market, expect the assessor to mark them up, and do it first yourself so the board sees a balanced analysis rather than a selective one.

Vacancy and collection loss: stabilized, not actual

Direct capitalization values a stabilized property. The vacancy and collection loss deduction should reflect the long-run occupancy a typical owner would expect for this building in this submarket, supported by submarket vacancy data, the subject's own leasing history and the competitive set. A building that is 96% leased in a soft submarket still carries a market vacancy allowance, because a buyer prices rollover risk.

The harder case is a building with actual vacancy well above market. Do not plug the actual vacancy into a direct capitalization model if the building is expected to lease up; a board will read that as capitalizing a temporary problem into perpetuity. The cleaner method is to value the property as stabilized and then deduct the cost to get there: rent loss during lease-up, tenant improvements and leasing commissions for the vacant space, and an entrepreneurial incentive if the market supports one. That below-the-line deduction is easier to defend because it ties directly to a leasing plan the owner can document.

Collection loss is separate from physical vacancy. Support it with actual bad-debt history. Keep it modest for credit-tenant NNN retail and higher for small-bay industrial or local-tenant strip centers if the record shows it.

Expenses and reserves that survive cross-examination

The expense side is where assessors push back hardest, so every line should answer one question: would a typical buyer underwrite this cost to own and operate the real estate? Normalize the actual statements against comparable operating expense data and against the property's own three-year history.

• Remove debt service, depreciation and amortization, and income taxes. They are financing and ownership costs, not operating costs of the real estate.
• Remove one-time capital expenditures such as a roof replacement or parking lot reconstruction, and replace them with an annual reserve for replacement.
• Annualize leasing costs. For multi-tenant office and retail, show tenant improvements and leasing commissions as a normalized per-square-foot allowance rather than the actual spend in a heavy rollover year.
• Set management at a market fee as a percentage of effective gross income, even if the owner self-manages or pays an affiliate.
• Exclude property taxes from expenses when you use a loaded cap rate, and say so explicitly in the narrative.
• Reconcile reimbursements. On NNN and modified gross leases, recoveries offset expenses, so show both sides of the ledger and let the board follow the net.

Capitalizing with a loaded rate

When the property tax line is the thing under appeal, deducting the actual tax bill bakes the disputed assessment into the value you are using to challenge it. The standard fix is a loaded cap rate: leave property taxes out of the expense deduction and add the effective tax rate to the base capitalization rate. The effective tax rate is the nominal rate multiplied by the assessment ratio. In a 100% state it equals the combined rate; in Cook County it reflects the 25% Class 5a level, the state equalization factor and the local rate.

The example below is Northgate Corporate Center, a 148,000 sq ft Class B suburban office building assessed at $19.4 million. Against that assessment, the indicated value of about $15.7 million supports a reduction of roughly $3.7 million, or 19%. At a 2.30% effective rate, that is about $85,000 a year in tax. Capitalize the same pre-tax NOI at an unloaded 8.00% and the value jumps to about $20.2 million, which is exactly the error to look for in an assessor's model.

Indicated value = Stabilized NOI before property taxes / (Base cap rate + Effective tax rate)

Reconcile, document and hand it to the board

An income approach rarely wins alone. Cross-check the indicated value against adjusted sales of similar buildings and, where the jurisdiction allows it, an equity comparison of assessed value per square foot. If the approaches disagree, explain why in the narrative instead of leaving the board to guess.

Document every input the way the board will test it. In Cook County, Board of Review Rule 20 calls for Schedule E filings for the three years before the lien date (or an affidavit with a signed income and expense statement), and the Assessor's office now expects Real Property Income and Expense (RPIE) data with income-producing appeals. In Texas, income and expense information an owner provides to the appraisal office is confidential under Tax Code §22.27, which removes a common objection to sharing it.

ATALI ELECTRIC's Income Valuation module handles the mechanical part of this work: it normalizes P&Ls and rent rolls, applies submarket vacancy and reserves, and capitalizes NOI at a loaded or unloaded rate with every adjustment logged. The judgment calls on market rent and stabilization stay with the consultant or appraiser who presents the case, which is where the board expects them to sit.