Cost-segregation studies

A cost-segregation study does not create another dollar of building cost. It rearranges when qualifying cost may be deducted.

That distinction gets mugged in sales presentations.

The parking lot is not the roof. The carpet is not the concrete. Land does not depreciate at all, no matter how enthusiastically someone colors the cell. A cost-segregation study sorts eligible costs into tax recovery periods so some depreciation may arrive earlier. The taxpayer gets the timing. The asset ledger inherits the IOU.

Done well, the study is classification backed by engineering and tax support. Done badly, it is a large first-year deduction with a report thin enough to slide under the examination-room door.

This is tax education, not tax, legal, or accounting advice. Eligibility, elections, placed-in-service dates, entity structure, state law, and each taxpayer’s ability to use losses require a qualified tax adviser.

The building needs a classified ledger

Start with total tax basis, not a vendor’s favorite percentage. Allocate the purchase price among nondepreciable land, the main building, land improvements, personal property, and any other supported categories. Then reconcile every classified dollar to the books.

The IRS’s February 2025 Cost Segregation Audit Technique Guide tells examiners to evaluate the study’s methodology, documentation, asset classifications, and cost reconciliation. The guide is not law, but it is a remarkably useful description of what an examiner may ask when the deduction stops being a sales pitch and becomes a tax position.

Engineering detail matters. Construction records matter. A report that declares “20% shorter life because multifamily” has classified the sales lead, not the property.

Watch $1.64 million change calendars

Use a simplified hypothetical purchase:

• Purchase price: $10,000,000.
• Land allocation: $1,500,000.
• Depreciable basis before the study: $8,500,000.
• Five-year property identified: $1,100,000.
• Fifteen-year land improvements identified: $600,000.
• Remaining residential rental building: $6,800,000.

Without cost segregation, a rough annual straight-line reference is $8,500,000 divided by 27.5 years, or about $309,091. That is not the exact first-year deduction because conventions and the placed-in-service month matter.

Now assume, only for illustration, that the $1,700,000 of shorter-life property is qualified property acquired and placed in service after January 19, 2025. Current IRS Publication 946 describes a 100% special depreciation allowance for certain qualified property acquired and placed in service after that date unless an applicable election changes the treatment.

The rough first-year picture becomes $1,700,000 of bonus depreciation plus about $247,273 on the remaining $6,800,000 building basis, before conventions and other adjustments: about $1,947,273. Compared with the rough $309,091 reference, roughly $1.64 million moved forward.

Read the verb. It moved. The property did not earn another $1.64 million, and the IRS did not mail it a congratulatory check. Cost segregation changed the deduction calendar.

The report has to show its work

Ask for the complete study, not the executive summary that met the graphic designer. Trace the classifications through:

• Closing statement, purchase agreement, appraisal, and land allocation support.
• Fixed-asset ledger and prior depreciation schedules.
• Architectural, mechanical, electrical, plumbing, and site plans.
• Contractor applications for payment, invoices, change orders, and equipment schedules.
• Site photographs, quantity takeoffs, unit costs, and estimating references.
• Asset-by-asset classification, recovery period, convention, and legal rationale.
• Reconciliation from study totals to depreciable basis and the filed tax return.
• Bonus-depreciation elections, placed-in-service support, and state adjustments.

An acquired building may not come with original construction invoices. Estimating methods can be used. Fine. The report should identify the method, data source, sampling, and reconciliation. “Our software knows” is not methodology. It is a witness refusing cross-examination.

The taxpayer can miss the early train

The shiny claim is that the study creates a $1.9 million first-year deduction. The sentence usually whispered afterward is that the taxpayer may not be able to use the resulting loss today.

Basis and at-risk limitations can matter. Rental losses are often subject to passive-activity rules. IRS Publication 925 explains that passive losses may be limited and carried forward instead of reducing unrelated active income today. State treatment can diverge from federal treatment.

Ask for an investor-specific illustration of the K-1 effect, not a promise of cash tax savings. A suspended passive loss may still have value. It is not the same event as a refund arriving next Tuesday.

The study can accelerate the deduction. It cannot accelerate the taxpayer through rules that block its current use.

The exit asks for every asset’s name

Depreciation reduces adjusted basis. When depreciable property is sold at a gain, some gain may be treated as ordinary income under recapture rules. IRS Publication 544 explains the recordkeeping and characterization issues for depreciable property, including section 1245 and section 1250 property.

In the hypothetical, taking $1.7 million of bonus depreciation reduces basis by that amount before the rest of the depreciation. That does not mean exactly $1.7 million will automatically be recaptured at one tax rate. Sale-price allocation, asset class, gain, holding facts, and applicable code sections control the result. It does mean the asset ledger remembers which deductions arrived early.

Request a disposition model that allocates sale proceeds among land, building, land improvements, and personal property. If acquisition had an itemized map but the exit collapses into one anonymous blob, somebody abandoned the ledger when it started sending invoices.

A late study has its own paperwork

A property already placed in service may still be reviewed, but changing depreciation treatment can be an accounting-method issue. Depending on the facts, the taxpayer may need Form 3115 and a section 481(a) adjustment rather than amended returns. That is CPA territory, not a switch in the sponsor model.

Ask what year the property entered service, what returns have been filed, what method was used, and how the catch-up adjustment will be reported. Tax time already elapsed. The paperwork must explain how the taxpayer is correcting the route.

Questions that make the study earn its fee

• Who prepared the study, and what tax and engineering credentials were involved?
• Does every dollar reconcile to basis after removing land?
• Which assets rely on estimates, samples, or residual percentages?
• What facts establish each placed-in-service date?
• Which assets qualify for bonus depreciation under current law?
• Did the taxpayer elect out or choose another permitted treatment?
• Can this investor use the projected losses, or will they be suspended?
• How do federal and state schedules differ?
• What recapture and adjusted-basis assumptions appear in the exit model?
• Who keeps the permanent asset records after the property manager, sponsor, or CPA changes?

Before celebrating anything, demand one basis bridge from purchase price to land, depreciable basis, study categories, first-year depreciation, ending adjusted basis, and the tax-return forms carrying each amount. Have the taxpayer’s CPA reconcile it to the study and the books.

Cost segregation does not mint deductions. It reschedules them, and the report owes proof for every dollar it sends forward.