Every fall we hear a version of the same question: "I'm closing on a rental in November, can I still get a cost segregation study done in time for this year's return?" The honest answer is usually yes, but "usually yes" hides a real timeline with a few dates that actually matter, and getting them backwards is how an investor who did everything right on the tax law ends up deferring a deduction they didn't need to defer. Here's the timeline that actually governs it.
Does your closing date decide which year's return gets the deduction?
Not by itself. Two dates matter, and they're not the same thing. The first is when you acquired the property, which for bonus depreciation purposes follows the binding-contract rule: 100% bonus depreciation applies to qualifying property acquired after January 19, 2025, meaning the purchase contract was signed after that date. Almost every closing happening now clears that bar without a second thought.
The second date is the one that actually decides which tax year the deduction lands on: when the property was placed in service. Depreciation, including the accelerated portion a cost segregation study identifies, starts in the year the property is placed in service, not the year you signed the contract and not the year you closed, if those dates differ from when the property was actually ready for its intended use. Close in November and place the property in service in November, and the deduction is available on this year's return. Close in November but don't get the unit rent-ready until February, and the clock resets to next year, no matter how early in the year you'd technically owned it.
What does "placed in service" actually require?
For a long-term rental, it generally means the unit is ready and available to rent, listed, habitable, and marketed, even if a tenant hasn't signed a lease yet. You don't need someone in the door by December 31, you need the property in a condition where someone could move in. For a short-term rental, the equivalent is having the listing live and bookable. If you're closing on a property that needs real rehab before it can be occupied or listed, that work, not the closing date, is what sets your placed-in-service date. Worth flagging to whoever's managing the renovation if the calendar matters to you.
What does the timeline actually look like from a November closing?
Assume you close in mid-November and the unit is rent-ready within a week or two, which is typical for a property that didn't need major work. From there, the study itself doesn't need much lead time. Residential cost segregation studies rely on the settlement statement, the purchase contract, and property details you provide, not a site visit, so engaging the study the same week you close is normal and the report can usually be finished well before your CPA needs it for filing, whether that's an April deadline or a return you already know you'll extend. The tight part of the calendar is rarely the study itself. It's making sure the property is actually placed in service before December 31, since that's the date nothing can move after the fact.
The math on a property that closes in November.
Take a $475,000 single-family rental, closing in November 2026, placed in service before year-end. With roughly 80% of the price treated as depreciable basis after carving out land, that's about $380,000 on the standard 27.5-year schedule. A reasonable residential study reclassifies around 22% of that basis into 5-, 7-, and 15-year property, roughly $83,600 moving into shorter recovery periods. With 100% bonus depreciation in effect, that full $83,600 is deductible in the year placed in service. At a 32% marginal federal rate, that's about $26,750 in tax savings landing on this year's return instead of next year's.
Miss placed-in-service by even a few weeks, say the unit isn't rent-ready until mid-January, and that same $26,750 doesn't disappear. It simply moves to next year's return. The deduction isn't lost. But it's twelve months later than it needed to be, and if you were counting on it to offset this year's income specifically, a February placed-in-service date won't do that for you.
What if you're not sure the property will be ready in time?
Talk to your CPA before December 31, not after, about what "placed in service" will actually look like for your specific property and your specific closing timeline; the answer turns on facts (listing status, habitability, whether rehab is standing between you and a tenant) that are easiest to fix while there's still calendar left to fix them. If timing is genuinely close, it's worth running the numbers on whether to do the study the year you buy or wait, since the answer isn't always "rush it."
If the property is closing and will be ready this quarter, the study side of this is the easy part. We don't need a site visit, we work from documents you likely already have from closing, and turnaround is built around investors who are trying to make a specific tax year, not around our convenience.