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Blog · Situations · 2026-07-31 · 2 min read

Commercial property: income is the argument

Commercial assessments turn on income, and the evidence is your own operating statements.

Residential appeals are about comparable sales and comparable assessments. Commercial appeals are usually about income.

The income approach

A commercial property's value is derived from the income it produces: net operating income capitalised at a market rate. If your actual rents, vacancy or expenses differ materially from the assessor's assumptions, the value is wrong and you have the records to prove it.

What to assemble

Rent roll, leases, three years of operating statements, vacancy history, and evidence of market capitalisation rates. If space is vacant, evidence you have genuinely tried to let it.

Why vacancy matters

Assessors typically apply a market vacancy assumption. A property with sustained above-market vacancy — for structural reasons, not neglect — is being assessed on income it cannot earn.

Entities need an attorney at PTAB

A corporation or LLC generally cannot represent itself before the Property Tax Appeal Board. Budget for counsel if you expect to go beyond the Board of Review.

The threshold question

Commercial appeals cost more to run and are worth more when they succeed. Estimate the annual saving, multiply by the years it will persist, and decide before spending on an appraisal.

This is general information about how Illinois assessments and appeals work. It is not legal advice, not an appraisal, and not a prediction about your case. Deadlines and rules differ by county — check yours with your Board of Review.

Check your own assessment free →

More on Situations

Condominium assessments: your best comparables are in your own building Units in one building share everything except floor, view and finish — which makes the comparison unusually clean.Vacant land: assessed on what it could be, not what it is Land assessment follows zoning, buildability and access. Any of those can be wrong on file.Rental property: no homestead exemption, every other remedy intact Landlords lose the exemption and keep the appeal. Condition is often the strongest argument.Inherited property: exemptions end, and the record is usually stale The exemptions died with the owner. The assessment probably has not been looked at in years.

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