Generate an Illinois commercial property tax appeal demand letter. Challenge over-assessments, meet deadlines, and protect your business under Illinois law.
Generate My Letter — $19Illinois commercial property owners pay some of the highest property taxes in the nation, and assessment errors are common. Whether your property is in Cook County's triennial reassessment cycle or a downstate township, you have a statutory right to challenge an over-assessment. Illinois law provides multiple layers of review: the township or county assessor, the County Board of Review, and the state Property Tax Appeal Board (PTAB) or circuit court. A well-drafted demand or appeal letter — supported by comparable sales, income data, or appraisal evidence — is often the fastest way to secure a reduction without litigation. Missing a single filing deadline, however, forfeits your appeal rights for the entire tax year, making timing and documentation critical.
Illinois property tax assessments are governed by the Property Tax Code, 35 ILCS 200/1-1 et seq. Commercial property is generally assessed at 33⅓% of fair market value statewide, except in Cook County where commercial and industrial property is assessed at 25% under the Cook County Real Property Assessment Classification Ordinance. Assessors must value property uniformly under Article IX, Section 4 of the Illinois Constitution, meaning similar properties must be assessed similarly. Over-assessment, lack of uniformity, and incorrect classification are the three most common grounds for appeal. The first level of formal appeal is the County Board of Review under 35 ILCS 200/16-55. Owners must file within 30 days of the assessment publication date for their township (Cook County uses rolling township deadlines posted by the Assessor). The Board considers evidence such as recent arm's-length sales, income and expense data for income-producing property, USPAP-compliant appraisals, and comparable assessments of similar properties. If the Board's reduction is unsatisfactory, owners have two parallel options under 35 ILCS 200/16-160 and 35 ILCS 200/23-5: (1) file a written appeal with the Illinois Property Tax Appeal Board (PTAB) within 30 days of the Board of Review's final decision, or (2) file a tax objection complaint in circuit court after paying the taxes under protest. PTAB proceedings are administrative, do not require an attorney for smaller claims, and decisions are based on equitable principles of fair cash value and uniformity. Circuit court actions follow standard civil procedure and are typically used for larger commercial portfolios or constitutional challenges.
An effective Illinois commercial property tax appeal letter functions as both a settlement demand to the assessor and a foundation for formal Board of Review or PTAB filings. Start by identifying the property by Property Index Number (PIN), tax year, and current assessed valuation. State the legal basis for the appeal — over-valuation, lack of uniformity, or misclassification — and cite 35 ILCS 200/16-55 to demonstrate you understand your statutory rights. Attach supporting evidence: three to five recent comparable sales adjusted for size, age, and location; a current income and expense statement with capitalization analysis if the property is leased; and assessment data for at least three comparable commercial properties showing lower per-square-foot valuations. Calculate the requested fair market value and corresponding assessed value, then quantify the tax savings using the local equalized assessed value multiplier and composite tax rate. Many Illinois assessors, particularly in Cook County, will negotiate informal reductions before a formal Board of Review hearing if the evidence package is strong. The letter should set a reasonable response deadline (typically 14 to 21 days) and state your intent to file with the Board of Review and, if necessary, the PTAB or circuit court. Send it via certified mail with return receipt to preserve a record. For Cook County properties, copy the Cook County Assessor's Office and reference the relevant township reassessment cycle. A professional, evidence-driven tone — not adversarial rhetoric — produces the best results.
Illinois Board of Review filings are free in most counties, though Cook County charges no fee for residential or small commercial appeals. PTAB filings are also free, but commercial appeals seeking reductions over $100,000 in assessed value require a formal hearing and typically benefit from counsel. Circuit court tax objections under 35 ILCS 200/23-10 require payment of the disputed tax under protest before filing and standard civil filing fees apply (typically $250-$400). The Illinois small claims limit is $10,000, but property tax appeals do not proceed through small claims court. Deadlines are jurisdictional and cannot be extended. Cook County uses a triennial reassessment cycle; downstate counties reassess quadrennially under 35 ILCS 200/9-215.
Property tax in Illinois is governed by the Illinois Property Tax Code (35 ILCS 200/1-1 et seq. (appeals: 35 ILCS 200/16-160; PTAB: Article 16, Div. 5)). Assessment cycle: General (quadrennial) reassessment every four years in most counties; Cook County reassesses on a triennial (three-year) cycle by geographic triad. Assessment date is January 1 of the tax year. Assessed value: 33 1/3% (one-third) of fair market value statewide (the Illinois Department of Revenue targets a 33.3% level of assessment). Cook County uses classification: approximately 10% for residential and 25% for commercial/industrial, reconciled via a state equalization multiplier.
Illinois Department of Revenue (state oversight/equalization); county Boards of Review and township/county assessors (local); Illinois Property Tax Appeal Board (PTAB) for statewide appeals. The window to act is short — board of Review: within 30 days of publication of the township assessment list (deadlines vary by county/township). Property Tax Appeal Board (PTAB): petition must be postmarked within 30 days of the Board of Review's final written decision; faxed/emailed appeals not accepted.
A recent change to watch: 2025-2026 reforms: General Homestead Exemption maximum set (up to $10,000 for 2025, with 2026+ indexed to lesser of 5% or CPI); Senior Freeze income limit raised from $65,000 (2025) to $75,000 (2026). Property tax debt/tax-sale reform (2026 legislation) aimed at helping homeowners retain equity, extending Cook County's annual tax-sale schedule.
Evidence that works: Comparable sales, comparable assessments (equity/uniformity grids), recent independent appraisals, a recent arm's-length purchase price, and documentation of property condition or income/expense data. PTAB weighs comparables by similarity in age, design, size, and features.
Next-level appeal: Illinois Property Tax Appeal Board (PTAB) — a five-member statewide quasi-judicial body; alternatively, taxpayers may seek judicial review by filing a tax objection complaint in the circuit court. PTAB decisions are reviewable by the Appellate Court under the Administrative Review Law.
Appeal deadline: Board of Review: within 30 days of publication of the township assessment list (deadlines vary by county/township). Property Tax Appeal Board (PTAB): petition must be postmarked within 30 days of the Board of Review's final written decision; faxed/emailed appeals not accepted.
First-level appeal: County Board of Review (BOR) — a quasi-judicial body providing an informal venue to resolve assessed-value disputes (some counties allow an informal review with the township/county assessor first). In Cook County, an initial appeal may be filed with the Cook County Assessor before the Board of Review.
Grounds you can raise: Overvaluation (assessment exceeds 33 1/3% of fair market value) and lack of uniformity/assessment inequity (property assessed higher than comparable properties). Decisions are based on equity and the weight of the evidence (35 ILCS 200/16-160).
How your value is assessed: 33 1/3% (one-third) of fair market value statewide (the Illinois Department of Revenue targets a 33.3% level of assessment). Cook County uses classification: approximately 10% for residential and 25% for commercial/industrial, reconciled via a state equalization multiplier.
Exemptions to claim: General Homestead Exemption (up to $10,000 EAV in Cook County / $6,000 in other counties for 2026); Senior Citizens Homestead Exemption ($5,000, age 65+); Senior Citizens Assessment Freeze (income limit raised to $75,000 for tax year 2026); Returning Veterans' Homestead Exemption ($5,000 for two years); Disabled Veterans' Standard Homestead Exemption ($2,500 for 30-49% disability, $5,000 for 50-69%, total exemption for 70%+); plus Home Improvement and Persons with Disabilities exemptions.
The hearing: Board of Review: informal hearings (written submission or in-person). PTAB: appeals may be decided on written evidence submissions; a formal in-person or telephonic hearing may be requested. The Illinois Supreme Court has affirmed that payment of the tax is NOT a prerequisite to appeal to PTAB.
First, county Board of Review (BOR) — a quasi-judicial body providing an informal venue to resolve assessed-value disputes (some counties allow an informal review with the township/county assessor first). In Cook County, an initial appeal may be filed with the Cook County Assessor before the Board of Review.
If that fails, illinois Property Tax Appeal Board (PTAB) — a five-member statewide quasi-judicial body; alternatively, taxpayers may seek judicial review by filing a tax objection complaint in the circuit court. PTAB decisions are reviewable by the Appellate Court under the Administrative Review Law.
Mind the deadline: board of Review: within 30 days of publication of the township assessment list (deadlines vary by county/township). Property Tax Appeal Board (PTAB): petition must be postmarked within 30 days of the Board of Review's final written decision; faxed/emailed appeals not accepted.
$19 flat. State-specific. Ready in 5 minutes.
Fight My Property Tax →