Cost Basis and Depreciation Records: How the IRS Reconciles the Study

A cost segregation study does not exist separately from the taxpayer's accounting records. The 2025 IRS Cost Segregation Audit Technique Guide directs examiners to reconcile the cost basis shown in a study to the taxpayer's books and records and to determine whether the study results can be reconciled to the taxpayer's depreciation or fixed asset schedules. That review can reveal duplicated assets, unsupported basis, missing project costs, or differences between the study and the tax return. For commercial real estate investors, the lesson is simple: an engineering allocation is strongest when every allocated cost can be traced back to the property's records.

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Key Takeaways

• Cost basis reconciliation connects the cost segregation study to the taxpayer's books, fixed asset records, and depreciation schedules.
• The IRS compares study costs with detailed depreciation records and investigates differences between the two.
• A study can contain correct classifications but still require correction if its costs do not reconcile to the taxpayer's actual records.
• Construction records, invoices, job cost reports, contracts, and general ledger data can help establish the actual cost of individual property elements.
• Investors should maintain a clear accounting trail from project costs to fixed assets and ultimately to the depreciation schedule.
• A duplicated equipment cost can create an allocation problem even when the study's total appears to match the taxpayer's reported basis.
• Every allocated cost needs a traceable path back to the property's records.

What Is Cost Basis Reconciliation?

Cost basis reconciliation is the process of comparing the costs assigned to assets in a cost segregation study with the costs recorded in the taxpayer's books and depreciation records.

The purpose is straightforward.

The study classifies property and assigns costs to those assets.

The taxpayer's accounting records show how the property was actually recorded.

The two should be capable of being reconciled.

The ATG specifically states that cost segregation study results should be easily reconcilable to the taxpayer's depreciation or fixed asset schedules.

The examiner is therefore not looking only at the classifications.

The examiner is also asking whether the costs assigned to those classifications are supported.

This makes reconciliation an important connection between engineering analysis, accounting records, and tax reporting.

For broader context on what makes a study accurate and well documented, see what defines a quality cost segregation study.

How Does the IRS Reconcile the Study to Depreciation Records?

The ATG describes reconciliation as a specific examination step.

Examiners should request detailed, asset-by-asset depreciation schedules that tie to the tax return.

They then determine how the assets identified in the cost segregation study appear on those schedules.

The ATG directs examiners to review tax depreciation schedules to verify that tax basis reconciles with the study and to look for possible differences.

That review can include questions such as:

• Are fixtures, furnishings, and equipment included in the study?
• Do those costs also appear on another depreciation or fixed asset schedule?
• Have any costs been duplicated?
• Do prior-year depreciation schedules reconcile to prior-year returns?
• Were reclassified assets depreciated using the proper method?

The examiner is essentially building a bridge between the engineering study and the tax return.

If the bridge does not connect, the difference needs to be explained.

That does not automatically mean the study is incorrect.

It means the records need to be investigated.

Why Does Reconciliation Matter to Investors?

A cost segregation study can contain sophisticated engineering analysis and still create questions if the financial records do not support the resulting allocation.

For example, a study may identify a piece of specialized equipment as 5-year property.

The engineering classification may be well supported.

But if that same equipment was already recorded separately in the taxpayer's fixed asset schedule and the study also includes it in the project cost, the basis may have been counted twice.

The issue is not the classification.

The issue is the cost.

The ATG specifically tells examiners to look for duplicated costs and to determine whether separately acquired assets appear elsewhere in the taxpayer's records.

This distinction is important for investors.

Classification answers what the asset is. Reconciliation answers whether the cost assigned to it is actually part of the basis being analyzed.

Both questions matter.

What Records Can Support Cost Basis?

The IRS examination process can reach beyond the final cost segregation report.

The ATG directs examiners to request contemporaneous records to substantiate and verify the cost basis of assets. Those records can include permits, design studies, contractor payment records, AIA payment documents, contracts, purchase orders, and invoices.

Project information can also be important.

The ATG identifies Capital Expenditure Requests and Authorizations for Expenditure as examples of records that can help verify project costs, identify related purchases, and determine the intended use of property.

For larger construction projects, the records may include:

• General ledger data
• Job cost reports
• Contractor pay applications
• Change orders
• Purchase orders
• Vendor invoices
• Owner-furnished equipment records
• Construction contracts
• As-built drawings

The ATG also instructs examiners to review construction costs that may not appear on contractor pay applications, including change orders, indirect costs, and out-of-pocket costs.

This is where engineering and accounting evidence meet.

The engineer needs to know what was built and how it functions.

The cost records need to show what was paid for it.

The reconciliation needs to connect the two.

Where Does Engineering Fit Into Cost Reconciliation?

Cost reconciliation is not simply an accounting exercise.

The ATG explains that cost analysis requires the examiner to consider how construction costs were allocated to individual assets and whether the resulting asset basis is correct.

That requires understanding the physical property.

Suppose a contractor's job cost report contains one broad electrical cost code.

The cost segregation study may divide that amount among several property elements based on engineering take-offs, drawings, specifications, and functional analysis.

The reconciliation question becomes:

Can the engineering allocation be traced back to the actual project cost?

That is where CostSegRx engineers apply the same principle used throughout our methodology:

What exists?

Why does it exist?

What does it support?

How is it installed?

What documentation supports it?

How should the cost be reasonably allocated?

Engineering produces the supportable conclusion. Tax treatment follows that conclusion.

For more on the engineering process, see how engineers perform cost segregation.

What Happens When the Study Does Not Match the Project Cost?

The ATG says a quality study should reconcile total allocated costs to total actual costs.

This is one of the principal elements of a quality study.

If the study's total allocation does not match the actual project cost, the difference needs to be investigated.

Possible causes can include:

• Missing project costs
• Separately acquired property
• Owner-furnished equipment
• Change orders
• Indirect costs
• Incorrect unit costs
• Incorrect quantities
• Costs recorded in another account

The ATG specifically warns that using different estimating techniques or cost guides for different property groups can create cost distortions. A quality study uses a consistent approach and reconciles the resulting allocation to the purchase price, project cost, or applicable property cost.

The objective is not to force the numbers to match.

The objective is to understand why they should match and identify what explains any difference.

Why Does Separately Acquired Property Matter?

Separately acquired equipment is a common source of reconciliation problems.

Imagine a construction project with a total contract amount that excludes furniture, fixtures, and equipment purchased directly by the owner.

If the study starts with the total construction project cost, it should not automatically add a separate cost for those items unless the analysis is intended to include them and the basis is appropriately accounted for.

The ATG addresses this directly.

If furniture, fixtures, and equipment are already included in the total project cost, allocating costs to those items can be appropriate.

If they were acquired separately and are not included in the total project cost, assigning additional costs to them would create a duplication problem.

This is why the engineer and accounting team need to understand the source of the total project cost.

The starting number matters.

You cannot determine whether an allocation is correct without knowing what the original cost actually includes.

How Can Investors Maintain Better Cost Records?

Investors can improve reconciliation long before an IRS examination occurs.

The key is maintaining a clear record of how capital expenditures move from project planning to completed assets.

Useful practices include:

• Maintain project-specific accounting records
• Keep contracts and change orders
• Preserve contractor pay applications
• Track owner-furnished equipment separately
• Maintain vendor invoices
• Document capital expenditures
• Keep fixed asset schedules current
• Preserve construction drawings and specifications
• Document placed-in-service dates
• Reconcile completed projects to the general ledger

The ATG's construction guidance explains that project costs are often recorded in a construction-in-progress or work-in-progress subledger and later transferred to a fixed asset account or depreciation schedule when the asset is placed in service.

That transition creates an important recordkeeping trail.

When those records are preserved, a future engineer can more easily understand the property's financial and engineering history.

This is consistent with the CostSegRx principle that cost segregation is an engineering inventory of the property's depreciable assets.

The inventory should remain useful throughout ownership, not simply at the time the original study is prepared.

For another investor-focused discussion of documentation and examination readiness, see cost segregation audit readiness.

Illustrative Reconciliation Example

Illustrative example only. Figures shown are estimated for demonstrative purposes only. Actual land allocations, asset classifications, depreciation, and tax results depend on the specific property, supporting documentation, engineering analysis, and taxpayer circumstances.

Assume an investor completes a commercial property project with a recorded project cost of $8 million.

The cost segregation study allocates that project into:

• $800,000 of 5-year property
• $1.2 million of 15-year land improvements
• $6 million of 39-year nonresidential real property

The three categories total exactly $8 million.

At first glance, the study appears to reconcile.

During a detailed review, however, the investor's records show that $200,000 of equipment was purchased directly from a vendor outside the construction contract.

The study also included that equipment in the $800,000 of 5-year property while the $8 million project cost already included the same $200,000 in a separate project accounting entry.

The problem is not the 5-year classification.

The problem is that the same cost has been counted twice.

After removing the duplicate, the study's allocated costs must be reconciled again to the actual basis being analyzed.

This illustrates why a simple total check is not enough.

Reconciliation has to work at the asset and cost-source level when necessary.

Engineering Principle

Every Allocated Cost Needs a Traceable Path Back to the Property's Records.

The IRS examination process does not stop at the final percentage or recovery period.

The ATG directs examiners to trace the study back to detailed depreciation schedules, books and records, project costs, contemporaneous documentation, and individual property elements.

That process protects against more than simple arithmetic errors.

It can reveal duplicated costs, unsupported basis, missing project costs, separately acquired assets, incorrect allocations, and differences between the study and the taxpayer's accounting records.

For investors, the lesson is practical.

Keep the construction records.

Keep the invoices.

Keep the job cost reports.

Keep the fixed asset schedules.

And make sure the completed project can be traced from its original costs to the assets that actually exist in the property.

That creates an engineering inventory that is also financially traceable.

Every allocated cost needs a traceable path back to the property's records.