In January 2025, the Cook County Assessor’s Office published a number that still comes up in appeal conversations. Commercial appeal appraisals came in at a median of 62% of later sale prices. If you file commercial appeals, that figure now shapes how your appraisal evidence gets read, so it helps to know what the study actually measured.
- What the Assessor’s 2025 study of appeal appraisals found and how it was built.
- Where the study’s own limits sit, and why the 62% figure still matters.
- What makes appraisal evidence hold up when someone compares it to a sale.
What the Assessor’s Study of Appraisal Evidence Found
The office matched appraisals filed in commercial appeals to later arm’s-length sales over $2 million. The sales ran from 2020 through 2023. After screening out mismatches, the study kept 60 appraisal-sale pairs: 52 commercial and industrial properties, plus 8 large apartment buildings.
The median appraisal came in at 62% of the later sale price. The mean was about 71%. In 49 of the 60 pairs, the appraisal fell below the sale. The spread between firms was wide, too. Median ratios by appraisal firm ran from 46% to 112%.
The Assessor’s framing was direct. If low appraisals are accepted routinely, the tax burden shifts to other owners, including homeowners. That argument gives every reviewer a public reason to test an appeal appraisal against the market.
What the Study Can and Can’t Tell You
The study is worth reading in full, because the office states its own limits plainly. First, the sample is not random. Owners only file appraisals that support a lower value, so appraisals above the assessment never reached the pool. The office says the results would likely improve if it saw those.
Second, time. Sales could occur up to three years after the appraisal’s effective date. A one-year window would have left only 24 pairs, so the office accepted the wider gap. Markets move in three years.
Third, size. With 60 pairs, the office calls its breakdowns by firm, attorney, and class statistically insignificant. Still, it concluded that there appears to be a systemic undervaluation. Those caveats soften the 62% figure. They don’t erase it.
A Hypothetical Shows How Time Moves the Ratio
Picture a hypothetical industrial building appraised at $4.0 million as of January 1, 2021. Industrial demand runs hot for the next two years. The building then sells in late 2023 for $5.6 million.
That pair produces a ratio of about 71%. Yet the appraisal could have been accurate for its date. The market simply moved after it.
Time cuts the other way, too. In the study, commercial buildings over three stories had a median ratio of 105%, which fits a falling office market. But two-to-three-story mixed retail buildings came in at a median near 48%. A gap that wide deserves a harder look than market timing alone.
Why the Bar for Appeal Appraisals Is Rising
The study didn’t change any filing rule. What it did was hand reviewers a benchmark. So an appraisal that sits far below a known sale, offer, or financing appraisal now draws questions faster.
In practice, the appraisals that hold up share a few habits. They use income and expenses supported by the market and the property’s own records. They reconcile the approaches instead of leaning on the lowest one. And when a recent sale disagrees with their value, they explain why rather than leave it out.
Our guide to what the Board of Review requires from an appeal appraisal covers the filing side. For how the income numbers should be built, see our breakdown of the income approach for commercial property. The difference between the Assessor’s model and a property-specific opinion is covered in mass appraisal vs single property appraisal.
What Commercial Owners Should Hand Over Early
A credible appeal appraisal starts with complete records. If you own the property, send the appraiser your rent roll, current leases, and two or three years of income and expense statements.
Then disclose anything that points to value. That includes a recent purchase, a listing, a written offer, or a lender’s appraisal from a refinance. If an appraisal ignores a number like that, it becomes easy to challenge. Also tell your attorney about it before filing, since they decide how the evidence gets used.
Write the Appraisal as if the Sale Is Coming
The simplest test for appraisal evidence is this: would it still look reasonable if the building sold next year? If the answer is yes, the report is doing its job. If it only works because nobody will check, it won’t hold up for long.
That means a report developed under USPAP Standards 1 and 2, built from the subject’s own income and condition, and reconciled to the sales the market actually produced. The legal strategy stays with counsel. The appraisal’s job is to give that strategy a value it can stand behind.
Will Your Appraisal Hold Up Next to a Sale Price?
We prepare Cook County appeal appraisals that reconcile to the market, so your filing starts from a value that survives comparison.
Frequently Asked Questions
What did the Cook County Assessor’s appraisal study find?
The January 2025 study matched 60 appraisals filed in commercial appeals to later sales over $2 million. The median appraisal was 62% of the sale price, and 49 of the 60 appraisals came in below the sale.
Does the study mean appeal appraisals get rejected?
No. The Assessor’s Office says it does not treat appraisals as the final word on value but may consider them. The study gives reviewers a benchmark, so appraisals far below known sales draw more questions.
Why can an accurate appraisal come in below a later sale price?
The study allowed sales up to three years after the appraisal date. If the market rose in that time, even an accurate appraisal will show a low ratio. The office also noted its sample only included appraisals filed to lower values.
What makes appraisal evidence credible in a Cook County appeal?
Market-supported income and expenses, a clear reconciliation of the approaches to value, and an explanation for any recent sale or offer that points to a different number. The report should be developed under USPAP Standards 1 and 2.
Should an owner tell the appraiser about a recent sale or offer?
Yes. An appraisal that ignores a known sale, offer, or lender appraisal is easy to challenge. Share it with the appraiser and your attorney before filing.
Appeal Appraisals Built to Be Tested
At PahRoo, every Cook County appeal assignment starts with the subject’s own rent roll, expenses, and condition, then checks the value against the sales the market has produced. Michael Hobbs and the appraisal team hold MAI and SRA credentials and prepare reports under USPAP Standards 1 and 2 for residential and commercial property. For how recent appeals reshaped the county’s tax base, read our Board of Review analysis, or explore our commercial appraisal services.