Cap Rate Selection for Property Tax Appeals: Extraction, Band of Investment and Loading

What review boards require of a cap rate

The rules ask for the same thing in different words: a rate drawn from the market for this kind of property on the valuation date. Texas Tax Code §23.012 directs the chief appraiser, when using the income method, to derive capitalization or discount rates from comparable data. In Cook County, Board of Review Rule 19 requires appraisals of income-producing property to base capitalization rates on current market data. A rate that cannot be traced to market evidence is an opinion, and panels treat it as one.

The valuation date matters as much as the source. Most jurisdictions value as of a fixed lien or assessment date (January 1 in Texas and Illinois), so a cap rate built from sales two years earlier, or from a market survey published after a sharp rate move, can be challenged on timing alone. Use sales and data as close to the valuation date as the market allows, and say how you adjusted for the gap.

Market extraction: the primary evidence

The strongest support is a cap rate extracted from actual sales of comparable properties: the NOI a buyer underwrote at the time of sale divided by the price paid. Two disciplines make extracted rates credible. First, the NOI must be stated on the same basis as the subject's NOI, so normalize each sale's income for vacancy, reserves and management the way you normalized the subject. Second, the sales must be arms-length and comparable in property type, class, location, tenancy and lease term.

The grid below supports the base rate for Cedar Point Medical Office, a 72,000 sq ft multi-tenant medical office building. The five sales bracket the subject and indicate a median of 7.90%. The assessor's model applies 7.40% to the property class, which sits below four of the five sales.

Band of investment and debt coverage as cross-checks

Where sales are thin, or to test the extracted rate, build the rate from the financing side. The band of investment weights the mortgage constant and the equity dividend rate by the loan-to-value ratio. With a 65% loan at 6.25% interest amortized over 25 years, the annual mortgage constant is about 7.92%. Weighted at 65%, that contributes 5.15%; a 35% equity position at an 8.00% equity dividend rate contributes 2.80%. The indicated base rate is about 7.95%, consistent with the extracted median.

The debt coverage method is a lender's version of the same check: debt coverage ratio times loan-to-value times mortgage constant. At a 1.25 coverage requirement, 65% leverage and a 7.92% constant, the indicated rate is about 6.43%, which marks the floor at which typical financing still works. A cap rate below that floor implies a buyer accepting thinner coverage than lenders would allow, which is a useful line of cross-examination when an assessor's rate looks low.

Present financing-based rates as support, not as the primary indicator. Boards tend to give more weight to what buyers actually paid than to a model of what they could have paid.

R0 = (LTV x Mortgage constant) + ((1 - LTV) x Equity dividend rate)

Match the rate to the NOI it divides

A cap rate is only meaningful against the income definition it was extracted from. The most common error in assessment models and owner appraisals alike is mixing definitions: a rate extracted from NOI after reserves applied to NOI before reserves, or a rate from stabilized sales applied to a property with in-place income well above market.

• Reserves: if the comparable NOIs deduct reserves for replacement, the subject's NOI must too, and vice versa.
• Leasing costs: tenant improvements and leasing commissions should be treated the same way above or below the line across the subject and every comparable.
• Lease structure: rates from NNN single-tenant sales do not transfer to a full-service multi-tenant building with expense risk the owner carries.
• Income basis: buyers of above-market leases pay for the leased fee; if your jurisdiction values the fee simple, adjust the comparable NOIs or the rate for the lease premium.
• Property taxes: rates extracted from sales are normally unloaded, because buyers' NOIs deduct taxes. Load them only when the subject's NOI excludes taxes, and never deduct taxes and load the rate in the same model.

Loading the rate for property taxes

When the assessment is the thing in dispute, the clean approach is to leave property taxes out of the expenses and add the effective tax rate to the base rate. The effective tax rate is the nominal rate multiplied by the assessment ratio: in a 100% state like Texas it equals the combined rate, while in Cook County it reflects the 25% Class 5a level, the state equalization factor and the local rate.

For Cedar Point, NOI before property taxes is $1,410,000 and the effective tax rate is 2.15%. The table shows how much the base rate and the loading decision move value. The assessor's 7.40% base rate, loaded, produces $14,764,000. The supported 7.90% base rate produces $14,030,000, a reduction of about $734,000 (5.0%) worth about $15,800 a year at 2.15%. The bigger error to catch is the unloaded line: dividing pre-tax NOI by an unloaded 7.90% overstates value by about $3.8 million, or 27%.

Loaded cap rate = Base cap rate + (Nominal tax rate x Assessment ratio)

Presenting the rate at the hearing

Show the rate on one exhibit: the extracted sales with their normalized NOIs, the band of investment and debt coverage checks, and a sentence reconciling them to the selected rate. State the NOI definition at the top so the panel can see that the rate and the income match. If the assessor's rate is lower, compare their support to yours line by line, because a rate without an extraction grid behind it rarely survives a direct comparison.

ATALI ELECTRIC's Income Valuation module stores the extraction grid with each sale's normalized NOI, runs the band of investment and debt coverage checks, and applies a loaded or unloaded rate with the choice recorded on the pro forma. The selection of the final rate stays with the consultant or appraiser presenting the case.