What if I disagree with a cost segregation classification?

You can exclude any component classification you are not comfortable defending and use only the classifications you find supportable. Contact the study provider to discuss the legal authority supporting any disputed classification.

Is this cost segregation study audit-defensible?

Audit defensibility depends on each reclassified component citing specific legal authority, the cost allocation methodology being documented and reproducible, and the observation methodology being described. A study meeting all 13 principal elements of the IRS ATG provides strong audit support.

Your Client Sent You a Cost Segregation Study

Q: What about the lookback method for cost segregation?

If the property was placed in service in a prior year, you file Form 3115 to change the accounting method. The Section 481(a) adjustment captures all prior-year missed depreciation in a single tax year. This is an automatic consent change (DCN 7) and does not require IRS approval.

Here's how to review it, verify the methodology, and file the deductions.

A cost segregation study reclassifies building components from 27.5-year or 39-year property into shorter MACRS recovery periods (5, 7, and 15 years), accelerating depreciation deductions. If your client has forwarded one to you, this page walks through what to look for, how to file it, and what to verify before signing the return.

What's in the Report

Component-by-component cost breakdown by IRS asset class (5-year, 7-year, 15-year, 27.5/39-year)
MACRS depreciation schedules with year-by-year deduction amounts
Land allocation methodology and reconciliation to depreciable basis
Legal authority citations for each classification (IRC Sections 1245/1250, Treasury Reg. 1.48-1(e), Rev. Proc. 87-56)
CPA-ready CSV export compatible with Lacerte, ProSeries, Drake, and UltraTax
Audit defense documentation including observation methodology and data sources

How to File It

Review the component breakdown. Verify that total allocated costs reconcile to the depreciable basis (purchase price minus land). The study should tie to within $1.
Check each IRS asset class assignment. Every accelerated component should cite a specific legal authority under Rev. Proc. 87-56 asset classes. Personal property (Section 1245) and land improvements (Section 1250) must be distinguished.
Complete Form 4562. Use the depreciation schedules provided in the study to populate Form 4562 for each recovery period. The CPA CSV import simplifies this step.
For lookback studies: prepare Form 3115. If the property was placed in service in a prior tax year, file Form 3115 (Application for Change in Accounting Method) to claim the Section 481(a) catch-up adjustment in a single year.
Attach the full study as audit support. The complete report serves as contemporaneous documentation. Keep it with the return workpapers.
Import the CPA CSV into tax software. The fixed asset schedule is formatted for direct import. Map columns to your software's asset entry fields (description, class, basis, placed-in-service date, method).

What to Verify

Land allocation is documented and reasonable (typically 15-25% for residential, varies by market)
Bonus depreciation elections match the placed-in-service date (100% for 2025 and forward under OBBBA)
Total allocated costs reconcile to depreciable basis within $1
Each accelerated classification cites specific legal authority (not just "per cost segregation study")
Indirect cost allocation methodology is documented with a stated rate
Section 1245 vs. 1250 recapture treatment is documented for each component category

Frequently Asked Questions

Is this study IRS compliant?

A properly prepared cost segregation study follows the IRS Cost Segregation Audit Techniques Guide (Publication 5653), which outlines 13 principal elements of a quality study. Key requirements include: engineering-based analysis, legal authority for each classification, reconciliation to depreciable basis, and documentation of the observation methodology. Review the study against these elements before filing.

Do I need to order my own study?

No. A cost segregation study is ordered by the property owner, not the CPA. Your role is to review the study for accuracy, verify the classifications are supportable, and file the resulting depreciation deductions on the return. If you find issues with the study's methodology, you can request corrections from the provider before filing.

What about the lookback method?

If the property was placed in service in a prior year and the owner has been depreciating the entire building as 27.5-year or 39-year property, you file Form 3115 to change the accounting method. The Section 481(a) adjustment captures all prior-year "missed" depreciation in a single tax year. This is an automatic consent change (DCN 7) and does not require IRS approval. The study should include the 481(a) adjustment calculation.

What if I disagree with a classification?

If a specific component classification appears aggressive or unsupported, you can exclude that component from the filing and use only the classifications you are comfortable defending. The depreciation schedules can be recalculated without the disputed items. Contact the study provider to discuss the legal authority supporting the classification.

Is this study audit-defensible?

Audit defensibility depends on three factors: (1) each reclassified component cites specific legal authority, (2) the cost allocation methodology is documented and reproducible, and (3) the observation methodology is described. The IRS ATG specifically looks for these elements. A study that meets all 13 principal elements provides strong audit support. Review the methodology section of the report for specifics.

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This page is for informational purposes only and does not constitute tax or legal advice. Consult a qualified CPA or tax attorney for guidance specific to your client's situation.