A cost segregation study is one of the most powerful tax strategies available to commercial real estate owners in 2026, and a broker opinion of value is the starting point for making it work. The One Big Beautiful Bill Act, signed July 4, 2025, permanently restored 100% bonus depreciation for qualifying property placed in service after January 20, 2025. Combined with cost segregation, this creates an environment where 20% to 40% of a commercial building’s cost basis can potentially be written off in year one. But before a cost segregation engineer begins their analysis, they need a defensible current value for the property. That value comes from a BOV.

A BOV for IRS compliance and cost segregation support is not a certified appraisal and cannot substitute for one when lender documentation, estate tax returns, or formal USPAP compliance is required. But as the market-based foundation for tax strategy planning, depreciation analysis, and property-level basis documentation, a current BOV from a licensed commercial broker is the practical and cost-effective starting point that CPAs and cost segregation engineers need before they can begin their work.

How a BOV Supports Cost Segregation Studies

A cost segregation study reclassifies components of a commercial building from the standard 39-year depreciation schedule (27.5 years for residential rental) into shorter-life categories of 5, 7, or 15 years. The result is dramatically accelerated depreciation deductions in the early years of ownership. Combined with permanent 100% bonus depreciation, qualifying components can potentially be written off entirely in year one.

The cost segregation engineer’s analysis is based on the property’s acquisition cost or construction cost as their starting point. For properties acquired through purchase, the purchase price establishes the total depreciable basis minus land value. For properties owned for several years where a retroactive cost segregation study is being considered, a current BOV helps establish the current market context and replacement cost considerations that inform the analysis. For properties being refinanced, acquired, or transferred where the basis is being reset, a current BOV is the market anchor for the entire tax planning process.

The 20/20 Rule for Cost Segregation

A practical rule of thumb used by commercial brokers and CPAs to quickly estimate cost segregation benefit: approximately 20% of a commercial property’s purchase price typically represents land value, which is not depreciable. The remaining 80% is depreciable basis. Of that depreciable basis, approximately 20% often qualifies for 100% bonus depreciation through cost segregation reclassification into 5-year, 7-year, or 15-year asset categories. For a $2 million commercial property, that suggests roughly $320,000 in potential year-one accelerated depreciation. For a $5 million property, approximately $800,000. Every property is different, and a CPA should be consulted for property-specific analysis, but the 20/20 rule gives a useful order-of-magnitude estimate before engaging an engineering firm.

When Commercial Property Owners Request BOVs for IRS Compliance

• Before commissioning a cost segregation study. A current BOV establishes the market context for the property and confirms whether the investment in a cost segregation study makes financial sense given the property’s value, basis, and tax situation.
• At acquisition of a commercial property. The best time to perform a cost segregation study is at acquisition, when the purchase price establishes fresh depreciable basis. A BOV at acquisition confirms the market supports the purchase price and provides a current value reference for all subsequent tax planning.
• Before a retroactive cost segregation study. For properties owned for multiple years where no cost segregation was previously performed, a retroactive study using IRS Form 3115 can claim catch-up depreciation. A current BOV provides market context that supports the retroactive analysis.
• Qualified Opportunity Zone investments. Properties in Qualified Opportunity Zones involve complex basis and holding period rules that interact with depreciation strategy. A current BOV supports the ongoing documentation of property value required for QOZ compliance and reporting.
• Section 1031 exchange basis tracking. When a property is acquired through a 1031 exchange, carryover basis rules affect what depreciation the new owner can claim. A current BOV helps the CPA establish the relationship between market value and depreciable basis at the time of the exchange.
• IRS audit support for depreciation deductions. When an IRS examiner questions the cost segregation methodology or asset classifications claimed on a tax return, a market-based BOV from a licensed commercial broker provides an independent, contemporaneous reference for property value that supports the study’s foundation.

The 2026 Bonus Depreciation Environment

The One Big Beautiful Bill Act permanently restored 100% bonus depreciation for qualifying property placed in service after January 20, 2025. Before this legislation, bonus depreciation had been phasing down: 80% in 2023, 60% in 2024, and was scheduled to drop to 40% in 2025 and 20% in 2026 under the original Tax Cuts and Jobs Act timeline. The permanent restoration means every dollar reclassified by a cost segregation study into a shorter-life asset class can potentially be written off entirely in year one, with no scheduled phase-down.

For commercial property owners, this creates the most favorable depreciation environment in modern tax history. A $2 million commercial property with $400,000 in cost segregation-eligible components would have generated approximately $160,000 in year-one deductions under 40% bonus depreciation. Under permanent 100% bonus depreciation, the same study generates $400,000 in year-one deductions. The difference is not incremental. It is transformational for the investor’s cash flow and tax position in the year of acquisition or improvement.

BOV vs. Certified Appraisal for IRS Compliance Purposes

A BOV is a market-based opinion of value, not a USPAP-compliant certified appraisal. The IRS requires a qualified appraisal meeting specific regulatory standards for charitable contribution deductions above $5,000, estate tax returns, and certain other formal filings. For cost segregation studies, the IRS’s Cost Segregation Audit Techniques Guide requires a detailed, engineering-based study as the primary documentation. The property value itself is typically established from the acquisition cost on closing documents, not from a separate appraisal or BOV. A BOV supports the planning and market context for cost segregation strategy. A certified appraisal is required when the IRS or a lender needs a formal USPAP-compliant valuation for a specific compliance purpose.

Request a BOV for IRS Compliance and Tax Planning Support

CPAs, tax advisors, cost segregation engineers, and property owners may submit requests. Describe the tax planning context and any specific IRS documentation requirements. A licensed commercial real estate broker will review your request and follow up promptly.

Frequently Asked Questions

What is the relationship between a BOV and a cost segregation study?

A BOV establishes the current market value of the commercial property, which provides market context for the cost segregation analysis. The cost segregation engineer works from the property’s acquisition cost or depreciable basis, not from the BOV directly, but a current BOV confirms the market supports the basis being used and provides an independent market reference. For properties where the basis has changed through improvements, partial dispositions, or complex acquisition structures, a current BOV is particularly useful for establishing the market value context before the engineering analysis begins.

Is 100% bonus depreciation still available in 2026?

Yes. The One Big Beautiful Bill Act, signed July 4, 2025, permanently restored 100% bonus depreciation for qualifying property placed in service after January 20, 2025. This reversed the phase-down schedule under the original Tax Cuts and Jobs Act. As of 2026, every dollar reclassified by a cost segregation study into 5-year, 7-year, or 15-year asset categories can potentially be deducted entirely in year one. Always confirm the current rules with your CPA, as tax law can change.

What commercial properties benefit most from cost segregation?

Properties worth $750,000 or more where the owner has a meaningful tax liability to offset benefit most. Hotels, restaurants, medical offices, retail centers, industrial facilities, and multifamily properties typically have high proportions of short-life components that qualify for reclassification. Properties with significant tenant improvements, specialized equipment, or recent renovations have additional reclassification opportunities. The best time to perform a study is at acquisition or shortly after a major renovation, when fresh basis is being established.

What is a retroactive cost segregation study?

A retroactive study, sometimes called a look-back study, is a cost segregation analysis performed on a property that was acquired or placed in service in prior tax years. Using IRS Form 3115 (Application for Change in Accounting Method), the owner can claim catch-up depreciation in the current tax year for all the accelerated deductions that were available but not taken in prior years. This does not require amending prior returns. A current BOV provides market context that supports the retroactive analysis, particularly for properties acquired several years ago where market values have shifted.

Can a BOV help support an IRS audit of depreciation deductions?

A BOV from a licensed commercial broker provides an independent, market-based opinion of property value at a specific point in time, which can support the factual foundation underlying a cost segregation study during an IRS examination. The IRS Cost Segregation Audit Techniques Guide emphasizes the importance of engineering-based methodology and proper documentation. A contemporaneous BOV is one element of a comprehensive documentation package. It does not substitute for the engineering study itself, which must comply with IRS methodology requirements, but it provides the market value context that anchors the analysis.