Here’s a number that surprises most property owners: 20-40% of a commercial building’s total cost can be reclassified into shorter depreciation schedules — 5, 7, or 15 years instead of the standard 27.5 or 39 (IRS Publication 5653, 2025). That means instead of waiting decades to recover your investment through depreciation, you can front-load a massive tax deduction into the early years of ownership.
The tool that makes this possible? A cost segregation study. And with the OBBBA permanently restoring 100% bonus depreciation for qualified property acquired after January 19, 2025, the math has never been more compelling.
I’ve spent over 30 years combined — between our team’s Big Four tenure and our work at Tax Formulations — helping property owners reclassify assets and accelerate depreciation. Let me walk you through exactly how this works, when it makes sense, and what changed in 2025.
What Is a Cost Segregation Study?
A cost segregation study is an engineering-based analysis that breaks a building into its individual components and reclassifies assets from long-life property (27.5 or 39 years) into shorter depreciation categories — typically 5-year, 7-year, or 15-year recovery periods under the Modified Accelerated Cost Recovery System (MACRS) rules of IRC §168. The result is a dramatically larger depreciation deduction in the early years of ownership, which directly reduces taxable income and puts cash back in your pocket.
What gets reclassified? Components that aren’t truly structural. Think specialty electrical systems, certain HVAC components, flooring, cabinetry, parking lots, landscaping, fencing, security systems, and decorative finishes. These are all personal property or land improvements with shorter useful lives than the building shell — and the IRS allows you to depreciate them accordingly.
How Does Cost Segregation Create Tax Savings?
For a $1 million commercial property, industry data shows first-year tax savings typically range from $40,000 to $60,000 when a cost segregation study is performed, compared to roughly $25,600 per year under standard 39-year straight-line depreciation (Patrick Accounting, 2025). That’s not a minor timing difference — it’s a fundamentally different cash flow profile.
Here’s the core math. Without a study, you depreciate your entire building evenly over 27.5 or 39 years. With a study, the engineering team identifies components that qualify for shorter lives, and those assets get depreciated much faster. When you add bonus depreciation on top — which allows you to expense a percentage of eligible assets in year one — the acceleration becomes enormous.
Real example: A $2 million commercial property undergoes a cost segregation study. The engineering team identifies $625,000 in 5-year property and $500,000 in 15-year land improvements. With 100% bonus depreciation (for property acquired after 1/19/2025), that’s $1,125,000 in first-year deductions — versus $51,282 under standard 39-year depreciation. At a 37% tax rate, that’s roughly $397,000 in year-one tax savings.
What Changed With the OBBBA and Bonus Depreciation?
2025 Legislative Update
The One Big Beautiful Bill Act, signed July 4, 2025, permanently restored 100% bonus depreciation for qualified property acquired and placed in service after January 19, 2025 (EisnerAmper, 2026). This is a transformative development for cost segregation — and it’s permanent, not temporary.
Before the OBBBA, bonus depreciation was phasing down under the TCJA: 80% in 2023, 60% in 2024, 40% in 2025, and headed to zero by 2027. That phasedown had been steadily reducing the first-year benefit of cost segregation studies. The OBBBA reverses that entirely for new acquisitions and construction.
Bonus Depreciation Timeline — Know Your Dates
Property acquired before 1/20/2025
Subject to the TCJA phasedown rates: 40% bonus for 2025 placements, 20% for 2026. Cost segregation still valuable, but the multiplier is smaller.
Property acquired on/after 1/20/2025
100% bonus depreciation — permanent. Every dollar of reclassified 5-year, 7-year, and 15-year property can be fully expensed in year one. This is the best environment for cost segregation since 2017.
New: Qualified Production Property (QPP)
The OBBBA introduced 100% bonus depreciation for certain nonresidential real property used in qualified production activities — potentially converting entire production facilities from 39-year to immediate expensing (KBKG / IRS Notice 2026-16).
Who Benefits Most From a Cost Segregation Study?
Properties valued at $500,000 or more in depreciable basis typically see the strongest ROI — study costs of $5,000-$15,000 often generate $40,000-$200,000+ in first-year savings, delivering 5x to 30x returns (Madras Accountancy, 2025). But property value alone doesn’t determine whether a study makes sense. Your tax bracket, hold period, and income type all matter.
A cost segregation study is likely worth it if you:
| ✓ | Own commercial, industrial, multifamily, or rental property with $500,000+ in depreciable basis |
| ✓ | Recently purchased, built, or significantly renovated a property |
| ✓ | Are in a mid-to-high tax bracket (24%+ federal) with sufficient income to absorb the deductions |
| ✓ | Plan to hold the property for at least 3-5 years |
| ✓ | Qualify as a Real Estate Professional (REP) under IRS rules — unlocking the ability to offset W-2 income with rental losses |
| ✓ | Operate a short-term rental with average stays under 7 days and material participation |
| ✓ | Own property that’s never had a cost segregation study — even if purchased years ago |
From our practice: The properties we see with the highest reclassification rates aren’t always the ones you’d expect. Restaurant build-outs, medical offices, and hospitality properties routinely hit 35-45% reclassification because they’re loaded with specialty electrical, plumbing, and fixtures that clearly qualify as personal property. Don’t assume a “simple” building means a small study benefit — the components inside are what drive the numbers.
What Does the IRS Expect in a Quality Study?
The IRS published a comprehensive Cost Segregation Audit Techniques Guide — updated in February 2025 as Publication 5653 — that lays out exactly what examiners look for. The guide identifies 13 principal elements of a quality study (IRS Publication 5653, 2025). This isn’t ambiguous guidance — it’s a detailed checklist.
Qualified Professionals
The study must be prepared by individuals with expertise in both engineering/construction and tax law. At Tax Formulations, Bob Montes brings 30+ years of cost segregation experience across EY, KPMG, PwC, GT, and RSM.
Engineering Analysis
The IRS expects detailed cost breakdowns using actual construction documents, blueprints, invoices, and site inspections — not desktop estimates or rules of thumb.
Audit-Ready Documentation
Total allocated costs must reconcile to actual total costs. Each asset classification must be supported by the applicable MACRS recovery period, legal authorities, and physical evidence.
Can You Do a Cost Segregation Study on Property You Already Own?
Yes — and this is one of the most underutilized opportunities in real estate tax planning. If you purchased, built, or renovated a property at any point in the past and never had a cost segregation study done, you can perform a “lookback” study and claim all the accelerated depreciation you missed in a single tax year using IRS Form 3115 (Application for Change in Accounting Method).
This isn’t an amended return. It’s a prospective change in your depreciation method that lets you take a “catch-up” adjustment — often called a Section 481(a) adjustment — in the year you file Form 3115. For a property owned for several years, this can result in a six-figure deduction in one tax year without touching prior returns.
Important nuance: Form 3115 lookback studies work even for properties acquired 10-15 years ago. However, the benefit calculation changes depending on how much depreciation you’ve already claimed and whether the property qualifies for current bonus depreciation rates. Our team models the full tax impact before recommending whether a lookback study makes economic sense for your specific property.
What About Depreciation Recapture When You Sell?
This is the most common concern I hear, and it deserves a direct answer. Yes, when you sell a property, the IRS recaptures the accelerated depreciation at ordinary income rates (currently up to 25% for real property) rather than the 20% capital gains rate. So there is a cost at sale.
But here’s why the math still works overwhelmingly in your favor: you’re comparing the time value of money today versus a tax event years in the future. A $200,000 deduction at a 37% rate puts $74,000 in your pocket in year one. If you hold the property for 7-10 years, the present value of the recapture tax is significantly lower than the immediate savings — especially when you reinvest those savings at a return.
A point most articles miss: Depreciation recapture applies whether or not you do a cost segregation study. If you sell a property for more than its depreciated book value, you’re paying recapture tax on the depreciation you claimed — even under the standard 27.5 or 39-year schedule. Cost segregation doesn’t create a new tax — it changes when you benefit from depreciation that’s already happening. The real question is whether you want that cash now or decades from now.
How Does the Cost Segregation Process Work?
At Tax Formulations, our cost segregation director Bob Montes oversees every project from scoping through delivery. Here’s what the process typically looks like:
Total time from engagement to delivered report is typically 4-6 weeks. Every study we deliver meets or exceeds the IRS’s 13 principal quality elements — because Bob has been on the other side of the table at EY, KPMG, PwC, and RSM, and he knows exactly what examiners look for.
Is Your Property a Good Candidate?
We’ll do a free preliminary analysis to determine whether a cost segregation study makes economic sense for your property — before you spend a dollar.
Frequently Asked Questions
How much does a cost segregation study cost?
Studies typically range from $5,000 to $15,000 depending on property type, size, and complexity. For properties over $500,000 in depreciable basis, the ROI generally falls between 5x and 30x — meaning the study pays for itself many times over in first-year tax savings alone. The cost of the study itself is also tax-deductible.
Will a cost segregation study trigger an IRS audit?
A properly conducted study following the IRS’s 13 principal quality elements actually reduces audit risk by providing the exact documentation examiners want to see. The IRS’s own Audit Techniques Guide states that quality studies “greatly expedite” their review. Our studies are built to withstand examination because our team has Big Four audit experience.
I bought my property years ago — is it too late?
No. You can perform a lookback study and claim catch-up depreciation using IRS Form 3115, even on properties acquired 10-15 years ago. The missed depreciation is recovered in a single tax year without amending prior returns.
Does cost segregation work for residential rental properties?
Yes. Residential rental properties (27.5-year MACRS) are excellent candidates, especially multifamily buildings, short-term rentals, and furnished units. Properties with average guest stays under 7 days that meet the IRS material participation tests can even use the losses to offset W-2 and business income — not just passive income.
How does cost segregation interact with the R&D tax credit?
They’re separate strategies that can complement each other. If you own the building where your R&D activities take place, cost segregation accelerates your real property depreciation while the R&D credit (IRC §41) reduces your tax liability for qualifying research expenses. Our team evaluates both simultaneously.
What Should You Do Next?
With 100% bonus depreciation permanently restored for new acquisitions, cost segregation studies are delivering the highest first-year returns we’ve seen in years. Whether you recently acquired a property, completed a renovation, or simply never had a study done on a building you’ve owned for a decade — there’s likely significant money to recover.
The first step is simple: contact us for a free preliminary analysis. We’ll review your property details and give you a realistic estimate of potential savings before you commit to anything. If the numbers don’t justify a full study, we’ll tell you that too.
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Martin Gamez
Founder, Tax Formulations
Martin is a tax credit specialist with over 25 years of experience in federal and state R&D tax credits, cost segregation, and business tax incentives. His background includes tenure at Big Four and Top 10 accounting firms, with clients spanning technology, manufacturing, aerospace, engineering, and life sciences. Read full bio →