Cook County Board of Review Commercial Appeals: Rules, Evidence and Timing

Where the Board of Review sits in the Cook County sequence

Cook County reassesses one third of the county each year on a triennial cycle (the City of Chicago, the north suburbs and the south and west suburbs in rotation), and the Assessor publishes values township by township. Each township then opens for appeals at the Assessor's office, generally for about 30 days, through the Assessor's online SmartFile system. When the Assessor certifies a township, the Board of Review opens the same township for complaints.

The Board is three elected commissioners, each representing a district, supported by analysts who review the evidence. It can lower or raise an assessment, and it hears complaints on every class of property, including commercial (Class 5a) and industrial (Class 5b) property assessed at 25% of market value and larger apartment buildings (Class 3) assessed at 10%.

Filing at the Assessor is not a prerequisite for filing at the Board, but skipping it gives up a free review. The practical sequence for most commercial parcels is: file at the Assessor with a complete income and expense submission, take the result, and file at the Board with the record tightened around whatever the Assessor's analyst did not accept.

Who can file and when the window closes

Under Board Rule 7, a complaint must be filed by the closing date the Board sets for the township, and Rule 8 allows every complaint to be filed online through the Board's website. Township windows are published on the Board's calendar and run for a set period after the township opens. A missed closing date ends the county-level appeal for that year, and with statutory windows typically 30 to 45 days nationally, a missed date can lock in an assessment for 1 to 3 years depending on the cycle.

Rule 1 matters more for commercial property than any other rule. Other than pro se taxpayers, every party before the Board must be represented by an attorney, and the rule names corporations, LLCs and condominium associations. Nearly all commercial real estate is held in an entity, so a consultant who prepares the valuation still needs an Illinois attorney of record. Under Rule 2, the Attorney Authorization Form must be on file before the complaint is finalized.

Evidence is due after the township closes. Rule 14 requires parties to file within the period the Board sets following the township closing, and Rule 13 makes late evidence generally inadmissible. Build the binder before the window opens, not after it closes.

The evidence rules that decide commercial complaints

The Board's 2026 rules spell out what an income-producing complaint must contain. An analyst who finds a required item missing can recommend no change without reaching the valuation argument, so treat these as a checklist rather than guidance.

• Rule 14B: a complete Historical Summary Form for income-producing property other than Class 2 residential.
• Rule 18: disclose any purchase within three years of the lien date, file the relevant sales documents, identify buyer and seller and any relationship, and state whether the sale was arm's length. If the price differs substantially from the Assessor's market value, add an affidavit explaining the sale.
• Rule 19: appraisals must be prepared by an Illinois-licensed or certified appraiser, comply with USPAP, value highest and best use as of the January 1 lien date, include an income approach for income-producing property, and use cap rates based on current market data. Rule 19J deems a non-compliant appraisal not credible evidence.
• Rule 20: where the property is leased or available for lease, file Schedule E of Form 1040 for the three years before the lien date, or an affidavit with a signed income and expense statement for the subject if no return was filed or the return combines properties.
• Rule 21: a vacancy claim needs a Vacancy-Occupancy Affidavit, dated interior photographs of the vacant space, and an affidavit on the duration, the reason and the leasing efforts.

Building the income argument the Board's analysts expect

The Board has told practitioners at its attorney meetings that income arguments should be supported by math, not sentences. That means a one-page pro forma: market rent, stabilized vacancy, normalized expenses, NOI, a supported cap rate and the indicated value, with the assessment level applied at the bottom. The analyst should be able to check every line against the Schedule E or income and expense statement in the file.

The example below is Lakeview Commons, a 64,000 sq ft neighborhood retail center in a north suburban township. The Assessor's market value is $11,800,000, an assessed value of $2,950,000 at the 25% Class 5a level.

The indicated value supports a market value reduction of about $1,523,000, or 12.9%, and an assessed value reduction of about $380,750. Assume a combined effective rate of 5.0% of market value: the annual tax saving is about $76,150. Note that the cap rate in the table is unloaded and property taxes sit in the expense line at a normalized level; if you load the cap rate instead, remove taxes from expenses and say so in the narrative.

Hearings, decisions and re-review

Many commercial complaints are decided on the written record. Rule 12 lets the taxpayer or attorney request an oral argument, the Board may limit how many it grants, and attorneys are capped at eight dockets per hearing call. Under Rule 13, missing a noticed hearing waives the oral argument. Write the binder as if no one will ever explain it in person, because often no one will.

After the decision letter, Rule 26 allows a request for re-review, but only within 3 days of the date of the Board's decision letter, only on one of the grounds the rule lists, with no new legal theories and no oral presentation. Rule 27 bars re-review of an Administrative No Change. Assign someone to watch decision letters during the township's decision period; three days passes quickly when a portfolio of parcels is in flight.

After the Board: PTAB or circuit court

If the Board's decision is not enough, the owner can appeal to the Illinois Property Tax Appeal Board within 30 days of the postmark date of the Board's written notice of decision. PTAB charges no filing fee, accepts additional evidence (an appraisal is generally the strongest), and gives the board of review up to 90 days to submit its own evidence. PTAB dockets are long, so a commercial appeal may take years to resolve, but a reduction applies to the year appealed and refunds follow.

The alternative is a tax objection complaint in the Circuit Court of Cook County after the taxes are paid. The two routes generally cannot both be used to challenge the same assessment for the same year, so decide early which forum fits the property and the evidence.

ATALI ELECTRIC's Deadline Tracker loads Assessor and Board of Review township windows, evidence due dates and decision periods, and the Petition Generator assembles the Board complaint package (pro forma, Schedule E summary, vacancy affidavit exhibits and comparable grids) for the attorney of record to review and file. ATALI ELECTRIC customers report evidence prep falling from 16 hours to 20 minutes per parcel.