Who Does Cost Segregation Studies?

The short answer Cost segregation studies are performed by engineering firms, specialized cost segregation companies, and CPA or tax firms with an in-house engineering team. The best providers have engineers on staff, follow the IRS Cost Segregation Audit Techniques Guide, carry recognized credentials such as ASCSP membership or the Certified Cost Segregation Professional designation, and stand behind their work with audit-defense support. You are not required to use your own CPA, but your CPA should review the result before it goes on your return.

The three main types of providers

Most cost segregation work is done by one of three kinds of firm. Understanding the differences helps you match a provider to your property. If you are still learning the fundamentals, our guide on what cost segregation is is a good starting point.

Provider type	Core strength	Watch for
Engineering firm	Component-level analysis the IRS prefers	May need a CPA to apply it on the return
Specialized cost seg company	High volume, refined process, audit defense	Confirm real engineering, not just software
CPA / tax firm with engineers	Integrated with your tax picture	Verify genuine in-house engineering capability

Engineering firms

Engineering firms, or firms with licensed engineers on staff, perform the component-level analysis at the heart of a study. Engineers are trained to read construction documents, estimate costs, and classify building systems, which is exactly the methodology the IRS prefers. A firm whose study is led and signed by a qualified engineer is well positioned on audit.

Specialized cost segregation companies

These firms do cost segregation as their primary business. They typically combine engineering and tax expertise under one roof and handle a high volume of studies across property types. Many of the best-known national providers fall into this category. Because this is all they do, strong specialist firms tend to have refined processes, deep experience, and dedicated audit-defense support.

CPA and tax firms with an engineering team

Some accounting firms offer cost segregation either with in-house engineers or through an engineering partner. The advantage is integration: the people running the study also understand your broader tax picture. The caution is that an accounting firm without genuine engineering capability is not the right fit for the physical analysis the IRS expects, so confirm that real engineering work is involved.

Does it have to be your CPA?

No. Your CPA files your return and advises on strategy, but most CPAs do not perform the engineering analysis themselves. The common and recommended arrangement is a specialist or engineering firm performing the study, with your CPA reviewing the report and applying it on your tax return. The two roles are complementary. For how the mechanics flow through to your taxes, see how cost segregation works.

National firms versus smaller providers

You will find both large national specialists and smaller regional firms in this market. National firms often bring high volume, established processes and the resources to support an audit for years after delivery, which can be reassuring on a large or complex property. Smaller firms can offer closer attention, local knowledge and sometimes a lower fee, which can suit a straightforward rental. Size is not a proxy for quality in either direction. A small firm with genuine engineering credentials and ATG-compliant methodology can deliver a stronger study than a large firm cutting corners, and the reverse is equally true. Judge the provider on credentials, methodology and audit support rather than on headcount or marketing reach.

What the engagement typically looks like

Knowing the normal flow helps you spot a provider who is skipping steps. A sound engagement usually moves through a predictable sequence:

• Feasibility estimate. The provider gives a no-cost or low-cost read on the likely benefit before you commit.
• Data gathering. You share purchase documents, closing statements, any construction records, and property details.
• Site analysis. An engineer inspects the property or conducts a detailed engineering review, documenting components with photos and measurements.
• Classification and report. Components are assigned to their proper recovery periods, with the reasoning documented in a detailed report.
• CPA handoff and support. You and your CPA apply the report on the return, and the provider stands ready to support it if examined.

Credentials that signal quality

Cost segregation is a largely unregulated field. Unlike filing a tax return, which requires a licensed preparer, almost anyone can market a cost segregation study, and quality ranges from excellent to worthless. Because there is no single license that gates the work, credentials and track record do the filtering that regulation does not. That is also why a low price with no credentials behind it should make you cautious rather than excited. Look for:

• Engineers on staff. The methodology the IRS favors is engineering-based, so a qualified engineer should lead and sign the study.
• ASCSP involvement. The American Society of Cost Segregation Professionals sets standards for the field, and membership signals a commitment to them.
• The Certified Cost Segregation Professional designation. The CCSP credential represents the highest level of professional achievement in cost segregation and requires years of documented experience, a sample report, peer references and an exam.
• Adherence to the IRS ATG. A provider should be able to tell you plainly that their studies follow the IRS Cost Segregation Audit Techniques Guide and its 13 quality elements.

How to vet a provider

Before you sign, put every provider through the same checklist. A confident, qualified firm will answer all of these easily:

• Who signs the report, and what are their credentials? Ask for the bio of the person putting their name on your study, and confirm engineering and ASCSP or CCSP background.
• Do you follow the IRS Audit Techniques Guide? The answer should be an unambiguous yes, with specifics.
• Is there a physical inspection or detailed engineering analysis? A property-specific analysis, not a generic percentage, is what makes a study defensible.
• Do you provide audit-defense support? Reputable firms stand behind their reports and will support you at no extra cost if the study is examined.
• How much experience do you have with my property type? Short-term rentals, multifamily, retail and industrial each have quirks, so relevant experience matters.
• What does it cost, and what is the turnaround? Get the fee and timeline in writing, and compare against the benefit you expect.

Red flags to avoid

• No named engineer and no professional signing the report.
• Allocations produced purely by software with no physical or engineering analysis.
• A benefit estimate that sounds far too good, with aggressive reclassification percentages.
• No mention of the ATG and no audit-defense support.

Matching a provider to your property

A small residential rental may be well served by a specialized firm offering a streamlined, engineer-reviewed study at a modest fee. A larger commercial building generally warrants a full engineering study from an established specialist or engineering firm with deep experience and robust audit defense. In every case, the deliverable you want is the same: a detailed, documented, engineer-backed report that follows the IRS guidance and that your CPA can confidently use on your return. To size the likely benefit before you choose a provider, run the numbers with our cost segregation calculator, and for pricing context see what a cost segregation study costs.

Choosing the right provider is less about brand names and more about evidence. Credentials, methodology and a willingness to defend the work tell you far more than a logo or a low price.

Frequently asked questions

Who does a cost segregation study?

Engineering firms, specialized cost segregation companies, and CPA or tax firms with an in-house engineering team. The common arrangement is a specialist or engineering firm performing the study while your own CPA reviews it and applies it on your tax return.

Can my CPA do a cost segregation study?

Some CPA firms offer cost segregation with in-house engineers or an engineering partner, but most CPAs do not perform the engineering analysis themselves. Typically a specialist firm performs the study and your CPA reviews the report and uses it on your return.

What credentials should a cost segregation provider have?

Look for engineers on staff, membership in the American Society of Cost Segregation Professionals, and ideally the Certified Cost Segregation Professional designation. The provider should also confirm that their studies follow the IRS Cost Segregation Audit Techniques Guide.

How do I choose a cost segregation company?

Ask who signs the report and their credentials, whether they follow the IRS Audit Techniques Guide, whether there is a physical or engineering analysis, whether they offer audit-defense support, and how much experience they have with your property type. Get the fee and timeline in writing.

Do I need an engineer for a cost segregation study?

The IRS favors an engineering-based study, so a qualified engineer should lead and sign the work. A provider without genuine engineering capability cannot perform the property-specific analysis the IRS expects, which weakens the study on audit.

This is general educational information, not tax advice. Cost segregation and depreciation rules are complex and change; consult a qualified CPA or tax advisor before acting.