A partner calls and asks for an appraisal. The first question back is never about the property. It is about the date. Retrospective vs current market value is not a preference either side gets to express. The filing, the statute or the court fixes the date, and everything else follows from it.
- Why a Cook County property tax appeal is a retrospective assignment, not a current one
- What the Assessor’s Rule 14 actually requires an appraisal to contain
- What the IRS uses for estate property, and why a sub-threshold estate may still need the work
Retrospective vs Current Market Value, the Short Version
Both are opinions of market value. But the effective date is different, and that difference drives everything else.
A current appraisal answers what the property is worth now, using what the market is doing now. A retrospective appraisal answers what it was worth on a fixed date in the past.
So for the second one, the appraiser rebuilds the market as of that date. Sales that had already closed. Rents in place then. Condition and use as they stood, along with the information a buyer could reasonably have had at the time.
One thing worth saying plainly to clients: a retrospective value is not a current value adjusted backwards. It is a separate analysis on a separate data set, and it usually takes longer than the current-date version of the same assignment.
In Cook County, a Tax Appeal Appraisal Is Always Retrospective
Illinois assessments attach to a lien date of January 1. The Official Appeal Rules of the Cook County Assessor use that phrase throughout, and every evidence rule in them counts forward or backward from it.
Think about where that puts you. When your township opens, January 1 is already months behind. By the time a file reaches the Board of Review, longer. At PTAB, longer still.
So an appraisal dated today answers a question nobody in the process asked. The effective date belongs on January 1 of the appeal year, and the report has to say so on its face.
The rules also put an outer limit on staleness. Under Rule 14, an appraisal offered in support of an appeal should be dated within the triennial period for that property, or at least no more than two years before the lien date of the appeal year.
What Rule 14 Asks the Report to Contain
This is the part worth reading before you commission anything, because it shapes the engagement. Rule 14 says an appraisal has to pertain to the property’s highest and best use, comply with USPAP and Illinois law, and be credible under USPAP.
Then the specifics. An original color photograph of the front of the subject, date stamped, plus photographs of every comparable used in the analyses. The PIN for the subject, and the PIN for every property used. Sales and market data that are available, reasonable and truly comparable, with no cherry picking. Where the income approach appears, cap rates drawn from relevant current market data.
And then the one that catches firms out. Filers must provide all appraisal reports and other valuation reports on the subject prepared within two years before the lien date, including reports prepared for financing or management purposes. The bank’s appraisal from fourteen months ago goes in the file whether it helps the argument or not. Better to know that before the engagement than after.
Two consequences round it out. An appraisal believed to be in gross violation of USPAP may go to the IDFPR, and it will not count as credible evidence. And the Assessor does not re-review its own appeal decisions, so the next stop is the Board of Review.
Date of Death Fixes the Estate Side
The federal rule is simpler to state, but it lands in the same place. The IRS treats the gross estate as an accounting of what the decedent owned at the date of death, valued at fair market value. Not what was paid for it. Not what it was worth when it was acquired.
For 2026 the filing threshold sits at $15,000,000. So a lot of people assume that nothing below it needs an appraisal.
Look at portability before you accept that. Passing a deceased spouse’s unused exemption to the survivor requires a timely filed estate tax return. So estates well under the threshold file anyway, and a filed return still needs values that hold up. Whether a given estate should file is counsel’s call, not ours, but the valuation work follows the decision either way.
These assignments are also retrospective almost by default. The engagement arrives after probate opens, sometimes years after, and litigation over an estate can push the effective date back further still.
When a Current Value Is the Right Instrument
Plenty of matters do call for today. Financing and collateral review. A sale or a partner buyout priced at present terms. Damages measured as of now, too, and settlement posture heading into mediation.
The test is the same one every time. What date does the governing rule, filing or order attach to? Once you answer that, the assignment writes itself.
One practical note for matters that need both. A single engagement can carry two effective dates, and it often should. Say so at the outset rather than halfway through, because the scope of work drives the research, the timeline and the fee.
Fix the Date Before You Order the Report
Three questions settle almost every one of these calls, so they are worth asking first. What date does the governing rule attach to. What does the body reading the report require it to contain. And what other valuations already exist on this property.
The third one catches people. A report your client never commissioned can still land in the record, and in Cook County the rules say it has to. Knowing that on day one changes how the file gets built.
Working a File With the Date Already Fixed?
Send us the matter, the date, and the body that will read the report. We will tell you what the assignment actually is before anyone commits to a scope.
Frequently Asked Questions
What is a retrospective appraisal?
It is an opinion of market value as of a specific past date, rather than as of today. The appraiser reconstructs the market as it stood then, using sales that had closed, rents in place, and the property’s condition and use at the time, rather than current conditions.
Can an appraiser adjust today’s value back to an earlier date?
No, and a report that appears to do so tends to draw scrutiny instead. A retrospective assignment is a separate analysis built on data from the effective date, not a current value indexed backwards.
What effective date does a Cook County property tax appeal use?
The lien date, which is January 1 of the appeal year. The Assessor’s appeal rules count from that date throughout, and Rule 14 asks that an appraisal be dated within the triennial period for the property, or at least no more than two years before it.
Does an estate under the filing threshold still need a date-of-death appraisal?
Often, yes, if portability is in play. Portability of a deceased spouse’s unused exemption requires a timely filed estate tax return, and a filed return needs values that hold up. Whether to file is a question for the estate’s attorney.
Can one appraisal cover two effective dates?
One engagement can, and for matters that need both a historical and a present value it usually should. Flag it at the outset, because two dates mean two sets of research and a different scope of work.
Appraisal Work Built for an Attorney’s File
PahRoo works out of Lincolnwood and covers Chicago and Cook County, along with Dallas, Philadelphia, Phoenix and Naples. Michael Hobbs, MAI, SRA, signs every report, and he is also available for testimony. Our commercial appraisal practice handles retrospective and current assignments for appeals, estates and litigation. There is more on the shifting politics of Chicago commercial tax appeals, and on what our Chicago coverage includes.