Cook County Assessor's Office Shares New Estimated Tax Rates

To provide transparency about its valuation methods, the Cook County Assessor’s Office released its estimated property tax rate for the 2025 reassessment of commercial properties in Cook County’s north suburbs. 

The CCAO’s method uses data-driven estimates of growth in the tax base to produce an estimated tax rate for use in its assessments of income-producing property.

An estimated property tax rate incorporates the effect of reassessments, which can cause significant changes to the tax base that lead to changes in the tax rate.

For Tax Year 2025, estimated growth in tax bases exceeds estimated growth in levies. This results in a decrease in the median estimated tax rate -- a trend consistent with the historical trend of tax rate decreases after a reassessment.

The release of this information follows a recommendation from the Cook County Property Tax Reform Group’s recent commercial valuation study.

An explanation of the CCAO’s calculations, along with a list of estimated tax rates by tax code, is available at https://github.com/ccao-data/public/tree/main/analyses/2025-rate-estimate.

For an explanation of how the CCAO values income-producing properties, see https://www.cookcountyassessor.com/how-commercial-properties-are-valued.

In Tax Year 2026, the CCAO plans to collaborate with the Cook County Board of Review to set estimated tax rates for the reassessment of the south and west suburbs in Cook County. Previously, both the CCAO and BOR used historical tax rates in their valuations.