What Is Cost Segregation?
Cost segregation is an engineering-based tax study that identifies building components eligible for accelerated depreciation under IRC Section 168. Instead of depreciating an entire commercial property over 39 years (commercial) or 27.5 years (residential rental) using the straight-line method, specific components are reclassified into 5-year, 7-year, or 15-year Modified Accelerated Cost Recovery System (MACRS) categories. The reclassification generates significantly larger deductions in the early years of ownership.
As described in "Billionaire Wealth Strategies" (Jim Dew, 2024), Chapter 9, cost segregation falls under the "R" (Reduce) component of the DEAPR framework.
How Does Cost Segregation Work?
A cost segregation study, performed by a qualified engineering firm, examines every component of a building: electrical systems, plumbing, flooring, landscaping, parking lots, specialized equipment, and decorative finishes. Structural components (load-bearing walls, roof structure, foundation) remain on the 27.5-year or 39-year schedule under IRC Section 168(c). Components classified as personal property or land improvements are reclassified to shorter recovery periods.
Under IRC Section 168(k) bonus depreciation provisions, reclassified components placed in service may be eligible for accelerated first-year deductions. For a $5 million commercial building, a cost segregation study might reclassify 20% to 30% of the cost basis into accelerated categories, generating $1 million to $1.5 million in first-year deductions. The One Big Beautiful Bill Act (Public Law 119-21) restored 100% bonus depreciation permanently for qualified property acquired after January 19, 2025, and struck the phase-down schedule. Property acquired on or before that date stays on the prior schedule, which allows 20% for property placed in service in 2026. A written binding contract fixes the acquisition date, so two properties placed in service in the same year can sit on different tracks.
IRC Section 179 provides an alternative for certain personal property components, allowing an immediate expense deduction of up to $2,560,000 for 2026, reduced dollar for dollar once more than $4,090,000 of Section 179 property is placed in service (IRS Rev. Proc. 2025-32). Section 179 and bonus depreciation can apply to different components within the same property.
Accelerated depreciation creates a timing benefit, not a permanent tax reduction. The deductions taken in early years reduce the property's adjusted basis, increasing the depreciation recapture under IRC Section 1250 upon sale. The recapture is taxed at a maximum rate of 25% for unrecaptured Section 1250 gain, compared to the ordinary income rate of up to 37% that the deductions offset.
When Do Entrepreneurs Use Cost Segregation?
Commercial real estate purchases of $1 million or more generally justify the study cost. The engineering study typically costs $5,000 to $15,000 and produces deductions many times that amount. The IRS addresses cost segregation in its Cost Segregation Audit Technique Guide, Publication 5653, revised February 2025. That guide is examiner training material and states on its face that it is not an official pronouncement of law; the authority for component-level depreciation rests on IRC Sections 167 and 168, Treas. Reg. Section 1.446-1(e), and case law including Hospital Corporation of America v. Commissioner, 109 T.C. 21 (1997).
New construction produces the highest reclassification percentages because detailed construction records allow precise component-level identification. Applying cost segregation during construction rather than after completion is more precise and cost-effective.
Renovations and tenant improvements can be studied separately for accelerated treatment. Qualified Improvement Property (QIP) placed in service after 2017 is depreciable over 15 years and eligible for bonus depreciation under IRC Section 168(e)(6).
Retroactive look-back studies capture missed accelerated depreciation from properties acquired in prior years. Under IRC Section 481(a) and the IRS list of automatic accounting method changes (currently Rev. Proc. 2025-23, designated change number 7), a change in accounting method on Form 3115 allows previously missed depreciation from open and closed prior years to be claimed as a single adjustment, without amending prior returns. Property placed in service in the immediately preceding year is treated separately and may instead call for an amended return.
How Does Dew Wealth Approach Cost Segregation?
Cost segregation is particularly effective when combined with QREP status under IRC Section 469(c)(7), which reclassifies real estate rental activities as non-passive. Without QREP status, accelerated depreciation losses are passive under IRC Section 469 and can only offset passive income. With QREP status, the losses offset ordinary business income, W-2 wages, or investment income.
The Fractional Family Office® coordinates the engineering study, verifies QREP qualification, and integrates the resulting deductions into the broader DEAPR tax strategy. The combined cost segregation and QREP approach can generate six-figure deductions against non-real-estate income in the first year of property ownership.
However, accelerated depreciation is a timing strategy, not free money. The larger upfront deductions reduce the property's tax basis, increasing the taxable gain upon sale. Investors must plan for the depreciation recapture tax under IRC Section 1250 and evaluate whether the time value of the deferred tax justifies the recapture liability.