In brief · 200 word summary: 1031 Exchanges and Cost Segregation
This guide explains the two most powerful tax tools in US real estate. A Section 1031 like kind exchange lets you defer capital gains tax when you sell an investment property and reinvest into another qualifying real property. The rules are strict: identify the replacement within 45 days and close within 180 days, both measured from the sale, keep the same taxpayer on both sides, use only real property held for investment after the 2017 law, and route the proceeds through a qualified intermediary so you never take receipt.
Cost segregation is an engineering and tax study that splits a building into shorter life components, 5, 7, and 15 year property, so those parts depreciate faster than the building itself. The power comes when this meets bonus depreciation. Under current law as described by tax practitioners following the 2025 act, qualifying property placed in service after January 19, 2025 can carry 100 percent bonus depreciation, letting eligible components be expensed in year one rather than over decades, which can substantially cut taxable income.
Used together, a 1031 exchange defers the tax on a sale while cost segregation accelerates deductions on the new asset. That is why sophisticated investors often pay far less current tax than headline returns suggest. Both are technical and fact specific. This is general education, and your own status and situation determine what these tools actually do for you, so work with a qualified CPA and tax attorney.
The essentials
- 1031 exchange: identify the replacement property within 45 days and close within 180 days, both measured from the sale of the relinquished property. Same taxpayer on both sides. Only real property held for investment or business use qualifies after the 2017 law. A qualified intermediary must hold the proceeds.
- Cost segregation: an engineering and tax study that splits a building into shorter life components (5, 7, and 15 year property) so those parts depreciate faster than the building.
- Bonus depreciation in 2026: under current law described by tax practitioners following the 2025 tax act, qualifying property carries 100 percent bonus depreciation, with the full deduction available for property acquired and placed in service after January 19, 2025. Property acquired on or before that date may remain on the prior phase down schedule.
Section 01The 1031 exchange: defer the tax, keep the capital working
When you sell an investment property at a gain, you normally owe capital gains tax. A Section 1031 like kind exchange lets you defer that tax if you reinvest the proceeds into another qualifying real property. The tax is not erased, it is deferred, which keeps more of your capital compounding in the next asset rather than going to the government now.
The rules are strict and the clock is unforgiving:
- 45 day identification. From the day you close the sale, you have 45 days to formally identify the replacement property or properties.
- 180 day close. You must complete the purchase within 180 days of that same sale date, not 180 days after identification.
- Same taxpayer. The entity that sold must be the entity that buys. Any entity restructuring should happen before the exchange begins.
- Like kind real property. After the 2017 tax law, only real property held for investment or business qualifies, and the replacement must be held for the same purpose.
- Qualified intermediary. You cannot touch the proceeds. A qualified intermediary holds the cash and applies it to the purchase, which preserves the deferral.
Section 02Cost segregation: pull depreciation forward
Real estate depreciates for tax purposes over a long schedule, typically decades for the building itself. Cost segregation is a study that identifies the parts of a property that are legally shorter lived, such as certain fixtures, flooring, and land improvements, and assigns them to 5, 7, or 15 year categories. Those shorter life components can be depreciated much faster.
The power comes when this meets bonus depreciation. Under current law as described by tax practitioners following the 2025 act, qualifying property placed in service after January 19, 2025 can carry 100 percent bonus depreciation, meaning eligible cost segregated components can generally be expensed in year one rather than over many years. That front loaded deduction can substantially reduce taxable income in the year of purchase or improvement.
Section 03Why it matters for a passive investor
- After tax return is the real return. Two deals with the same pretax return can differ meaningfully after tax. Understanding these tools helps you read a sponsor's projections critically.
- Ask how the sponsor handles it. A quality sponsor will often commission a cost segregation study and may structure for 1031 flexibility. It is a fair question to ask.
- Get your own advice. Your personal tax situation, including passive activity rules and your status as an investor, determines what these tools actually do for you. This is education, not a plan for your return.
Sources
- The Tax Adviser, like kind exchanges of real estate: https://www.thetaxadviser.com/issues/2025/sep/like-kind-exchanges-of-real-estate-building-on-the-basics/
- Wipfli, what is a Section 1031 exchange: https://www.wipfli.com/insights/articles/re-tax-what-is-a-section-1031-exchange-and-how-do-you-qualify-wipfli
- Grant Thornton, interim guidance on revived bonus depreciation, 2026: https://www.grantthornton.com/insights/newsletters/tax/2026/hot-topics/feb-03/interim-guidance-issued-for-revived-bonus-depreciation