By Daniel Ambrose, MAI, Executive Vice President, Tax Services — The Ambrose Group
Search “best cost segregation companies” and you’ll land on a page with stars, badges, and a top-ten list — put together by someone who has never seen your building. A ranking built before anyone knows your property type, your basis, or your records isn’t really ranking anything. It’s a guess dressed up as authority, and it’s the same rule-of-thumb thinking the IRS’s own audit guide ranks at the bottom of the list.
So instead of handing you another ranked list, here’s the checklist we’d actually want if we were the ones buying — the questions that tell you more about a firm in five minutes than any badge on their homepage. We’ll answer every one of them about ourselves, on the record, at the end.
Will they actually see the building?
The IRS’s Cost Segregation Audit Techniques Guide recommends a field inspection for every quality study, and calls it critical when construction drawings are limited or missing. A quote that skips the site visit is priced for a thinner deliverable — someone is working from photos or assumptions instead of what’s actually in your building. Ask directly: does your process include an on-site inspection, or just a document review?
Is the fee flat, or tied to what the study finds?
Some providers charge a percentage of the tax benefit they identify. The IRS’s own audit guide treats that pricing model as a caution flag — it gives the preparer a financial incentive to inflate the very numbers the study exists to support. A flat fee, scoped to the property and the records, doesn’t carry that incentive. Ask every firm you’re comparing the same question: does your fee change based on what the study finds? The right answer is no.
Who’s doing the land valuation, and how?
Land isn’t depreciable, so it has to come out of the basis before anything else gets classified. Some firms default to a flat percentage or simply use the appraisal district’s number. Better firms treat it as a basis allocation performed with real valuation discipline, aiming at a well-supported figure rather than a low one — because that discipline is what makes the number hold up if it’s ever questioned. Ask who performs the land analysis and what they’re basing it on.
Will they show you the report against the IRS’s own checklist?
Chapter 4 of Publication 5653 sets out thirteen principal elements the IRS itself uses to judge whether a study is high quality — covering things like the methodology used, the documentation behind it, how each component’s classification is justified, and whether the numbers reconcile to the actual construction costs. You don’t need to memorize all thirteen. You need one habit: ask any firm — ours included — for a sample report, and see whether it reads like it was built to survive that review, or built to look impressive on a cover page.
What’s the credential actually behind the work?
This is an unlicensed field — nobody is required to hold any specific credential to sell you a cost segregation study, which is exactly why it’s worth asking about. There’s more than one legitimate way to demonstrate competence: appraisal credentials like an MAI designation or a state appraiser license, a trade certification such as ASCSP or CCSP, or an engineering staff with real construction and cost-estimating experience. None of these alone is a substitute for the two questions above — but a firm that can’t point to any of them is a firm you should keep shopping past.
Do they work with your CPA, or around them?
Your CPA owns your tax position; a cost segregation firm should be producing the documentation that supports it, not competing with it. Ask how the firm coordinates delivery with your accountant, and watch for anyone who suggests you don’t need your CPA involved. That’s not a shortcut. That’s a provider who wants you to skip the person whose job is to catch their mistakes.
Will they ever tell you no?
There’s a basis level below which the fee can outweigh the benefit — with 100% bonus depreciation now permanent, that floor has moved down to roughly $500,000 of building basis for many properties, but it’s still a floor. And if you’re planning to sell within a year or two, depreciation recapture claws back part of the timing benefit, which changes the math again. A firm that says yes to every building regardless of basis or hold period is optimizing for its own fee, not your return. Ask what would make them turn the engagement down.
Where The Ambrose Group stands on this list
We’re appraisers first — MAI-designated, doing valuation work since 1994 — with an in-house construction engineer, which is a different starting point than most firms in this field bring to a study. We conduct a site inspection as a matter of practice. We treat the land allocation as a valuation question decided with appraisal discipline, not a default percentage. We ground what we build in the IRS’s own audit guide rather than a trade ranking, and we partner with your CPA instead of working around them. And we’ll tell you when the math doesn’t work for your property — a study you shouldn’t buy is not a relationship we want to start with.
We’re not going to publish a star rating for ourselves, for the same reason we wouldn’t trust one from anyone else. Run us through every question above. That’s the actual test — and we’ll answer it about our own work the same way we’re asking you to test everyone else’s.
Frequently asked questions
Are “best cost segregation company” rankings trustworthy? Treat them the way you’d treat a rule-of-thumb percentage on a study — a starting point, not a substitute for testing a firm against your own building. Most published rankings score things like website claims, years in business, or review counts, not the actual work product.
Does a bigger, national firm mean a better study? Not automatically. Scale can mean more resources behind your engagement, or it can mean your file gets a template. The questions above apply the same way to a five-person shop and a national chain — ask them of both.
Should price decide it? Price tells you what you’re being charged, not what you’re getting, in a field with no minimum standard for what “a study” has to include. Compare quotes on what’s included and excluded — site visit, land analysis, audit support — before you compare the number itself.
What’s the single best question to ask? “Can you show me a sample report, and walk me through how it holds up against the IRS’s own quality checklist?” A firm that answers that plainly, without deflecting to a ranking or a badge, is telling you more than any listicle will.
If you’d rather skip the research and just ask us the hard questions directly, that’s exactly what a first conversation with our cost segregation consultants is for. Bring your building, and we’ll answer on the record. Talk to our team.
No company other than The Ambrose Group is named or evaluated in this article. Criteria described are drawn from the IRS’s Cost Segregation Audit Techniques Guide (Publication 5653, rev. 2-6-2025) and general industry practice. Nothing here is tax advice for your situation, and meeting a criterion described above is not a claim that The Ambrose Group is the only firm that meets it.
Daniel Ambrose is Executive Vice President of Tax Services at The Ambrose Group, where he leads property tax consulting and cost segregation for commercial owners across Texas. With 16 years in real estate, Daniel built his practice on a simple premise: property tax firms aren’t interchangeable, and the ones that win value are the ones that understand it.