If you bought, built, or improved rental real estate and placed it in service in 2026, two separate questions matter: what each component is, and when federal bonus depreciation can apply. A cost segregation study answers the first. Bonus depreciation addresses the second. Used together, they can move qualifying components out of the long building schedule and into an earlier federal deduction. Neither changes land value. Neither eliminates the need for records.

See What A Study Can Reclassify

A study reviews construction invoices, plans, and the property. It may identify five-, seven-, or 15-year personal property and land improvements, such as certain dedicated electrical, plumbing, site, and specialty items. The remaining structural building is generally on the 27.5-year residential rental or 39-year nonresidential schedule. The exact result depends on the facts and the study's support.

A study does not make an item eligible for bonus by label. The component must satisfy the federal bonus rules on its own.

Match Each Class To The Bonus Rules

For 2026 federal planning, start with the component's recovery period and placed-in-service date. Federal bonus depreciation generally targets qualifying property with a recovery period of 20 years or less. That is why five-, seven-, and 15-year property found in a study is the usual place to test the bonus rules. Land and the building shell do not become bonus property merely because a study lists them.

Then confirm acquisition and use requirements, the property's original use or qualified improvement status, and any election or ordering rules. The federal percentage and transition rules depend on the law and the property's dates. Do not apply a rate from a prior project without checking the 2026 facts.

A bonus deduction may reduce the remaining basis available for regular depreciation. It may also affect passive-loss and at-risk calculations. A paper deduction is not the same as a current usable loss. Review basis and activity limits before treating the result as cash flow.

Keep QIP In Its Own Lane

Qualified improvement property, or QIP, is a separate category from five-, seven-, and 15-year components. It generally covers eligible interior improvements to nonresidential space, subject to statutory exclusions and placed-in-service rules. A study can identify QIP, but it should not relabel structural work, building expansion, elevators, escalators, or internal structural framework as QIP.

Review the asset list line by line. A QIP item and a personal-property item can have different support, recovery periods, and bonus eligibility. Ask the preparer to show the federal class, placed-in-service date, and reason for any bonus treatment.

Separate Federal And California Reporting

Federal and California depreciation are not interchangeable. California generally does not conform to federal bonus depreciation. A federal return may claim bonus on qualifying study components while the California return uses its own depreciation schedule and an adjustment. The cost-seg study still matters for California basis tracking. The federal acceleration may not carry over.

Keep a federal schedule and a California schedule for the same asset groups. Record original basis, reclassified basis, placed-in-service date, federal method, California method, and every adjustment. That avoids forcing the federal deduction onto the state return or losing the state basis trail.

Build The File Before Filing

Keep the signed study, engineering detail, fixed-asset ledger, closing statement, invoices, change orders, and placed-in-service evidence together. For an acquisition, confirm the date you became owner and the date the property was ready and available for its intended use. For a renovation, separate the improvement's in-service date from the building's original date.

On the federal return, the preparer may need Form 4562 and supporting depreciation schedules. The right form and election depend on the property and the tax position. Review the return for consistency between the study, fixed-asset ledger, and depreciation workpaper.

A Practical 2026 Review

Before filing, ask four questions:

Which assets did the study place in five-, seven-, or 15-year classes?
Which assets qualify for federal bonus under the 2026 rules and their dates?
Which items are QIP, and which are not?
What California adjustment and separate schedule will be carried forward?

If the property has a study from an earlier year, ask the CPA how a 2026 acquisition, renovation, or placed-in-service event changes the analysis. If you are considering a study, have the tax preparer and study provider agree on the asset list before the return is filed. LaviCPA can help you review the federal and California schedules for your property.

Not tax advice. This article is general information and is not a substitute for advice from a qualified tax professional who knows your facts.

Cost Segregation And Bonus Depreciation In 2026