In tax years 2023 through 2025, the Cook County Assessor closed 4,872 commercial, industrial and large-apartment PINs with no change and a reason code saying not enough data was submitted. Most went on to the Board of Review. There, 41.5% got a reduction. PINs the Assessor turned down on its own income, market or cost analysis did better at the Board: 56.6%.
The gap shows up in the Board's no-change codes. A third of the Board no-changes on those "insufficient data" PINs (33.6%) cited missing documents or a failure to follow Board rules. For the merit denials, it was 13.7%.
One point first, because it trips up new associates. Cook has no ordinance or state law that makes every income property owner file income and expense data each year. The requirement comes with the appeal. A 2019 bill, HB 2217, would have made annual filing mandatory in Cook. The sections it would have added to the Property Tax Code do not exist.
Quick Answer
Cook requires income and expense information when an income-producing property is appealed, not every year. At the Assessor, every commercial or apartment appeal must include the income and expense tabs in SmartFile (the Assessor calls the data RPIE), three years of tax schedules or audited statements, and leases or lease summaries, all by the township's closing date. Missing data can mean "no change." The Board asks for the same records under its own rules. A client who did not file can still go to the Board, but should expect the records question again.
What the Assessor requires
The Assessor's Rule 16 defines income-producing property as a parcel that is wholly or partly not owner-occupied and earns rent. Residential buildings with six or fewer units are excluded. Hotels and motels always count.
Every appeal on that kind of property must include:
- The RPIE tabs in SmartFile. Since RPIE 2.0, there is no separate RPIE filing and no RPIE code. The property characteristics and income and expense tabs are part of the commercial appeal itself.
- Three years of tax schedules. Schedule E, Form 8825, Form 1065 or IL-990-T, or audited or certified statements, for the three years before January 1 of the appeal year. If the client did not own the property that long, the Assessor has an attestation form.
- Leases. Full copies or detailed summaries showing the parties, lease type, square footage, rent and who pays the taxes. Apartment buildings over six units are excepted.
- A related-party affidavit covering any relationship between landlord and tenant beyond the lease.
Timing. Under Rule 10, the appeal and every supporting document are due by the township's closing date. The Assessor calls these hard deadlines and accepts nothing late except after a system error.
Penalty. There is no fine. The consequence is the result: the Assessor says incomplete or inaccurate income data may be grounds for "no change."
Confidentiality: plan for public
The Assessor's 2026 appeal guidelines say plainly that documents submitted to the office are public record. Filers must remove non-public personal information before filing: Social Security and employer ID numbers, driver's license numbers, account and card numbers. The Assessor will not do the redaction.
So what. A rent roll and operating statement filed with an appeal should be treated as a document anyone can request. Build redaction into the paralegal checklist, not into the last hour before the window closes.
How the Assessor uses the data
The Assessor values most commercial property with an income model: market rent, vacancy, expenses and a cap rate with a tax load added. It says those inputs come from third-party market data and from past appeal information for similar properties.
That second source matters. The income data your clients file does not just decide their own appeal. It feeds the market assumptions used for the next reassessment of similar buildings. Censum covers the model itself in how Cook County values commercial buildings.
What happens at the Board and PTAB
The Board's rules ask for much of the same record:
- Rule 20. For leased property, Schedule E for the three years before the lien date. If no return was filed, or several properties share one return, an affidavit plus a signed income and expense statement for the subject. Leases, lease summaries or rent rolls, and a related-party affidavit (apartment buildings over 12 units excepted).
- Rule 14(B). A complete Historical Summary Form for income-producing properties outside class 2.
- Rule 21. For vacancy claims, an occupancy affidavit, dated interior photos and proof of marketing.
At PTAB, market value can be shown by an appraisal, a recent sale of the subject, construction cost, or at least three comparable sales. PTAB decisions have given little weight to an income analysis built on actual income alone, without market rent, vacancy and cap rate support. Illinois case law treats a property's capacity to earn income, not its actual income, as the measure.
What the files need is set out in Censum's guide to the commercial evidence package. This piece is about what happens when the income piece is missing.
The record when the data was missing
PIN-level results for class 3 and class 5 PINs, by the Assessor's outcome and the same year's Board result:
| Assessor outcome | Tax year | PINs | At the Board | Board cut |
|---|---|---|---|---|
| No change, insufficient data | 2023 | 1,637 | 1,523 | 714 (46.9%) |
| No change, insufficient data | 2024 | 2,044 | 1,789 | 716 (40.0%) |
| No change, insufficient data | 2025 | 1,191 | 1,061 | 385 (36.3%) |
| No change, insufficient data | 2023-2025 | 4,872 | 4,373 | 1,815 (41.5%) |
| No change, Assessor's analysis supports value | 2023-2025 | 41,488 | 40,493 | 22,932 (56.6%) |
So what. A missing-data denial at the Assessor is not the end of the year: nearly nine in ten went on to the Board. But those files carried their gap with them. When the Board said no, it cited missing documents or rule failures a third of the time, more than twice the rate for files the Assessor rejected on the merits.
When a client didn't file: practical moves
- Treat the Assessor stage as a records test. If the client cannot produce tax schedules and leases before the township closes, the Assessor appeal is likely to come back "insufficient data." File it anyway only if the records will be ready.
- Use the gap before the Board window. The Board window opens after the Assessor's. Use those weeks to get the Schedule E, the rent roll and the leases.
- No return yet? Rule 20 lets the owner file an affidavit plus a signed income and expense statement with Schedule E detail.
- Can't fix it in time? Rule 27 lets the firm ask the Board for an administrative no change. It is not reviewed on the merits, but it keeps the PTAB and circuit court routes open.
- Plan the PTAB case as a value case. If the income record stays thin, an appraisal or sales case is the stronger route there.
- Fix next year now. Cook reassesses the City of Chicago in tax year 2027. Ask City clients for 2024 through 2026 records before their township opens.
Where Censum fits
Censum Docket gives a first read on any Cook PIN, including recent-sale signals and appeal history, and its firm-only commercial desk supports commercial files. Censum does not file appeals, is not a law firm and never takes a share of legal fees. The attorney files and makes every legal judgment.
The numbers behind this article
Censum's join of two Cook County open datasets, accessed November 11, 2026: Assessor Appeals (y282-6ig3) and Board of Review Appeal Decision History (7pny-nedm). From the Assessor data we took class 3 and class 5 PINs for tax years 2023 to 2025. "Insufficient data" means a no-change result with reason code 19 ("insufficient data having been submitted") or 18 ("lack of data") in any of the three reason fields. "Assessor's analysis supports value" means a no-change result with code 22 and neither code 18 nor 19. Each PIN counts once per year. We matched each PIN to the same tax year's Board decisions in the "Commercial and Industrial" and "Multi Family" major classes. A PIN counts as cut if any Board row for it shows a decrease. Board no-change reasons were read from the Board's own descriptions; "missing documents or rule failures" combines "no documentation submitted in addition to complaint form" and "failure to comply with Board of Review rules." The data does not say which document was missing.
FAQ
Does Cook County require annual income and expense filing?
No ordinance or state law requires it every year. The Assessor requires it with every appeal of income-producing property, and the Board asks for similar records.
What does RPIE mean now?
It is the Assessor's name for the income, expense, vacancy and characteristics data. Since RPIE 2.0 it is entered in tabs inside the SmartFile commercial appeal. There is no separate filing or code.
Are filed rent rolls confidential?
The Assessor's guidelines say documents submitted to the office are public record. Redact personal identifiers before filing.
Can we appeal at the Board after an "insufficient data" no change?
Yes. In 2023 to 2025, 89.8% of those PINs went on to a Board decision, and 41.5% of those got a cut.
Is there a fine for not filing income data?
No. The cost is the appeal result.
Does Censum file or represent clients?
No. Censum LLC is independent property tax intelligence and docket software. The attorney files and makes every legal judgment.
Sources
- Official Appeal Rules of the Cook County Assessor (2026), Rules 2, 10 and 16
- Cook County Assessor 2026 Appeal Guidelines
- Cook County Assessor RPIE page and RPIE one-pager (2020)
- Cook County Assessor: How Commercial Properties are Valued
- Cook County Assessor: Industrial and Commercial Appeals
- Cook County Board of Review Official Rules, Rules 14, 20, 21 and 27, last updated July 27, 2026
- 86 Ill. Adm. Code 1910.65, PTAB documentary evidence
- PTAB decision 2013-04216 and 2015-01624, on actual versus market income
- HB 2217, 101st General Assembly (2019), as introduced
- 35 ILCS 200/16-160, PTAB filing deadlines
- Censum join of Cook County Assessor Appeals and Board of Review Appeal Decision History, Cook County open data
Sources accessed November 11, 2026.
Next step
Check your commercial book for missing income records before the next township opens, starting with a first read in Docket. See Censum Docket
Censum LLC is a data and analytics company, not a law firm and not a tax advisor. Censum is independent and is not affiliated with Cook County or any government agency.