A cost segregation study is an engineering-based analysis that reclassifies parts of a building purchase into shorter recovery periods. It does not create a deduction that did not exist. It moves deductions forward, which matters because a dollar deducted against a high marginal rate today is worth more than the same dollar spread across three decades. This is where it stood in 2023, which was the year the market cooled and underwriting started to matter again.
What 2023 changed
2023 was the correction. Rates stayed high, supply that had been added during the boom arrived on the market, and occupancy in several previously unstoppable markets came down. The phrase that circulated was Airbnbust, which was overstated, and the underlying shift was real: revenue per property fell in markets where supply had grown fastest.
The spread between well-run and poorly-run properties widened sharply. In a market where everything fills, operational quality is invisible. In 2023 it was the whole difference.
Bonus depreciation stepped down to 80% for property placed in service in 2023, the first year of the TCJA phase-down.
How it works
A cost segregation study is an engineering-based analysis that reclassifies parts of a building purchase into shorter recovery periods. It does not create a deduction that did not exist. It moves deductions forward, which matters because a dollar deducted against a high marginal rate today is worth more than the same dollar spread across three decades.
- An engineer or qualified specialist inspects the property and the closing documents and allocates the purchase price across component classes.
- Carpet, appliances, decorative fixtures, specialty electrical and furnishings typically fall into 5 or 7-year property.
- Driveways, walkways, landscaping, fencing, site utilities and pools typically fall into 15-year land improvements.
- The reclassified components then become eligible for bonus depreciation at the rate in force for the placed-in-service year.
What that meant in 2023 specifically
With bonus depreciation at 80%, a cost segregation study still produced a large first-year deduction, and the arithmetic changed enough that the study cost had to be weighed more carefully on smaller purchases.
The properties that got into trouble in 2023 were bought at peak prices with thin reserves in markets that were absorbing new supply. None of those three alone was fatal. Together they were.
2023 rewarded buyers who could underwrite honestly and walk away. Basis mattered more than it had in years, because there was no longer a rising tide to cover an overpay.
This is an explanation of how the rules worked, not tax advice. My BnB Accelerator, LLC is a real estate acquisition firm, not a CPA firm. Our independent partner firm is AE Tax Advisors.
Where it goes wrong
The failure modes are consistent across years, which is itself useful information: they are not caused by the market cycle, so a different year does not protect you from them.
- Doing the study on a property that does not clear the seven-day test, which leaves the accelerated loss passive and largely stranded.
- Planning a short hold. Recapture on sale returns much of what the study deferred, so the strategy rewards a long hold or an exit structured as a 1031 exchange.
- Commissioning the study so late that the report does not exist before the filing deadline.
What a buyer should have done in 2023
2023 rewarded buyers who could underwrite honestly and walk away. Basis mattered more than it had in years, because there was no longer a rising tide to cover an overpay.
The underwriting discipline does not change with the year. Twelve individual monthly revenue figures from a comparable set you assembled, a complete expense stack including reserves, and a stress test at 75% of projection that still covers debt service.
We screen roughly a thousand deals a week and eliminate about 98% of them. That ratio has held across every year on this site, through the boom, the correction and the stabilisation, because it is a function of how listings are selected rather than of the market.
What generalises, and what does not
Reading a year in isolation is the most common analytical error in this business. 2023 had its own conditions, and someone who learned the wrong lesson from it carried that lesson into a market that no longer rewarded it.
What generalises is the mechanics above. The definitions, the tests, the sequence and the failure modes are the same in every year on this site, which is why they are worth learning properly once rather than relearning each cycle.
What does not generalise is the environment: the cost of capital, the depth of supply, the bonus depreciation percentage, and the regulatory posture of a given jurisdiction. Those change, sometimes abruptly, and a model that treats them as fixed is a model that was only ever right about one year.
The practical consequence is to build the analysis so the environment is an input rather than an assumption. A property that only works at one interest rate, one occupancy level and one tax treatment is not an investment thesis, it is a bet that nothing moves.
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Frequently asked questions
What was different about cost segregation on a short-term rental in 2023?
2023 was the correction. Rates stayed high, supply that had been added during the boom arrived on the market, and occupancy in several previously unstoppable markets came down. The phrase that circulated was Airbnbust, which was overstated, and the underlying shift was real: revenue per property fell in markets where supply had grown fastest.
What was the main risk in 2023?
The properties that got into trouble in 2023 were bought at peak prices with thin reserves in markets that were absorbing new supply. None of those three alone was fatal. Together they were.
What was bonus depreciation in 2023?
Bonus depreciation stepped down to 80% for property placed in service in 2023, the first year of the TCJA phase-down.