Tax planning for real estate investments has always been detailed work, and one strategy stands out in 2026: cost segregation. It accelerates depreciation and puts tax savings in an owner's hands in the early years of ownership. The One Big Beautiful Bill Act, signed July 4, 2025, made this strategy stronger by bringing back 100 percent bonus depreciation on a permanent basis, which applies to the short-life components a cost segregation study identifies. This post covers how cost segregation works in 2026, how it pairs with permanent bonus depreciation, and when to time a study.
A cost segregation study is a detailed analysis that breaks down the components of a property into different categories for tax purposes. Instead of depreciating the entire building over a standard 27.5 years (for residential properties) or 39 years (for commercial properties), certain parts of the building—like furniture, fixtures, and land improvements—can be depreciated over shorter periods of 5, 7, or 15 years. By front-loading depreciation, property owners can significantly reduce their taxable income in the early years of ownership, boosting cash flow and improving investment returns.
For example, if you purchase a commercial property for $5 million, a cost segregation study might allow you to reclassify $500,000 of assets as 5-year property, $250,000 as 7-year property, and $750,000 as 15-year property. This reclassification can lead to an immediate increase in depreciation deductions, enhancing your tax savings dramatically compared to a standard depreciation schedule.
For several years bonus depreciation was scheduled to disappear, dropping from 100 percent to 80, then 60, on a path to zero by 2027. The OBBBA reversed that. For qualified property acquired and placed in service after January 19, 2025, the bonus depreciation rate is 100 percent, and that rate is now permanent.
Bonus depreciation applies to depreciable assets with a recovery period of 20 years or less, which is exactly the 5, 7, and 15-year property a cost segregation study pulls out of a building. That overlap is what makes the two strategies work together: the study reclassifies the components, and 100 percent bonus depreciation lets an owner write them off in full in the first year.
One timing rule matters. The building has to be acquired and placed in service after January 19, 2025 for its reclassified components to qualify for the full 100 percent. A property bought under a binding contract dated before January 20, 2025 stays on the old schedule, which means 40 percent for components placed in service in 2025.
For real estate investors, a cost segregation real estate strategy isn't just about tax savings—it's about improving cash flow. By accelerating depreciation, investors can reinvest their savings into new properties, make improvements, or simply bolster their cash reserves during the critical early years of ownership.
The strategy is particularly useful for owners of large commercial properties or those with multiple residential units. High-cost improvements like parking lots, sidewalks, and security systems can be depreciated over shorter schedules, providing immediate financial relief. Even if you’ve already owned your property for several years, a "look-back" cost segregation study can unlock retroactive tax benefits through catch-up depreciation.
Conducting a cost segregation study typically involves hiring a specialized firm with engineering and tax expertise. The study includes an on-site review and analysis of architectural drawings, electrical plans, and mechanical systems. These components are then categorized into different depreciation schedules.
The average cost of a study ranges from $5,000 to $15,000 depending on the property size and complexity.
However, this upfront expense often pays for itself many times over in tax savings.
Timing a cost segregation study still matters, with bonus depreciation now permanent. Running the study in the year a property is acquired or placed in service lets an owner apply 100 percent bonus depreciation to the reclassified short-life components right away. This allows investors to begin benefiting from accelerated depreciation right away, maximizing their cash flow during the critical early years of ownership.
That said, if you’ve owned a property for several years, don’t worry—look-back studies allow you to claim missed depreciation in a single tax year, providing a substantial "catch-up" deduction.
With 100 percent bonus depreciation now permanent, cost segregation is no longer a race against a closing window. It is a strategy an owner can plan around every year. The components a study identifies can be fully expensed in the year they are placed in service, and Section 179 sits alongside it as a second tool.
For 2026, Section 179 lets business owners deduct qualifying property up to $2.56 million, with the deduction phasing out after $4.09 million of property is placed in service. Paired with cost segregation, this is most useful for owner-occupied commercial property and qualifying improvements. The OBBBA also added a separate provision, Section 168(n), that allows full expensing of certain nonresidential real property used in manufacturing or production, when construction begins after January 19, 2025 and the property is placed in service before 2031.
Cost segregation has a lot of moving parts, and the 2026 rules reward getting the timing right. That’s where TaxPlanIQ comes in. Designed specifically for tax professionals, TaxPlanIQ allows you to easily create and customize tax plans for your clients. With its comprehensive database of tax strategies—including cost segregation—it offers a clear and easy-to-follow guide on how to implement these strategies to maximize your clients' savings.
By using TaxPlanIQ, you can streamline the cost segregation process, from identifying qualified assets to showing the tax savings potential for your clients. Best of all, you can create branded tax plans in just a few clicks, helping you expand your advisory services and grow your firm’s revenue.
Curious about how TaxPlanIQ can help you offer high-value services like cost segregation to your clients? Sign up for a free demo today and see how this innovative tool can transform your tax planning services.
What is a cost segregation study?
A cost segregation study is an engineering-based analysis that separates a building into its components and assigns them to shorter depreciation schedules. Instead of writing off a whole commercial building over 39 years or a residential rental over 27.5 years, parts like fixtures, flooring, and land improvements move to 5, 7, or 15-year schedules. That front-loads deductions into the early years of ownership and improves cash flow.
Did OBBBA bring back 100% bonus depreciation?
Yes. The One Big Beautiful Bill Act restored 100 percent bonus depreciation and made it permanent for qualified property acquired and placed in service after January 19, 2025. This reversed the earlier phase-down that had dropped the rate to 60 percent in 2024 and was set to reach zero by 2027.
How does cost segregation work with bonus depreciation in 2026?
The two stack. A cost segregation study reclassifies building components into 5, 7, and 15-year property, and bonus depreciation applies to property with a recovery period of 20 years or less. So the short-life components a study identifies can be fully expensed in the first year under 100 percent bonus depreciation, rather than spread across decades.
How much does a cost segregation study cost?
Most studies run between $5,000 and $15,000, depending on the size and complexity of the property. For owners of larger commercial or multi-unit properties, the first-year tax savings often exceed the cost of the study by a wide margin.
Can you do a cost segregation study on a property you already own?
Yes. A look-back study lets you capture depreciation you could have claimed in prior years and deduct it in a single year, without amending past returns. The catch-up is reported through an accounting method change on Form 3115. This works for properties placed in service in earlier years.
What types of property qualify for cost segregation?
Most income-producing real estate qualifies, including commercial buildings, residential rentals, short-term rentals, and owner-occupied business property. Properties with significant fixtures, site improvements, or specialized systems tend to produce the largest reclassifications. The building has to be used in a business or held for the production of income.
When is the best time to do a cost segregation study?
The strongest timing is the year a property is acquired, built, or placed in service, since that is when the reclassified components can be fully expensed under 100 percent bonus depreciation. One rule to watch: a property under a binding contract dated before January 20, 2025 stays on the old bonus schedule, which means 40 percent for components placed in service in 2025.
Can real estate investors use cost segregation losses against other income?
It depends on how the activity is classified. Passive investors are generally limited to using the losses against passive income. Investors who qualify as real estate professionals, or who materially participate in a short-term rental, may be able to apply the deductions against other income.