On $1 million of depreciable basis (excluding land), a cost segregation study can produce $200,000 to $400,000 in first-year deductions.
Since the One Big Beautiful Bill Act made 100% bonus depreciation permanent, that is the normal math for property acquired and placed in service after January 19, 2025, not a temporary loophole.
Property acquired under a binding written contract signed before that date still falls under the old phase-down rate. For anything you want counted on your 2026 return, the date that matters is December 31.
Most investors know bonus depreciation is back. Fewer have set up their fourth quarter around it.
The ones who do will go into 2027 with more after-tax cash than investors who wait, and their competitors may never figure out where it came from.
Why the Fourth Quarter Matters This Year
Between 2023 and 2025, bonus depreciation was scheduled to step down every year: 80%, then 60%, then 40%. That schedule made investors careful.
A deal that slipped from December into January lost a chunk of its first-year deduction, so many people stopped treating depreciation as a reason to time a deal.
Now 100% is the permanent rate for qualifying property, so the question is when you place an asset in service, not which year's rate you get.
Any qualifying component placed in service by December 31 is deductible in full on this year's return. If it slips into January, the same deduction moves back a full year.
For an investor with a strong income year, that difference is significant. A deduction is worth the most in the year you have income to offset, and for many REF members, 2026 has been that kind of year.
You can also read: Commercial vs. Residential Real Estate ROI in 2026.
What Cost Segregation Does
A building is not one asset for tax purposes. A cost segregation study, usually done by an engineering-based firm, separates a property into its parts.
Carpet, cabinetry, specialty electrical, parking lots, landscaping, and site lighting have shorter lives than the 27.5 or 39 years assigned to the structure.
Those 5-, 7-, and 15-year components qualify for 100% bonus depreciation.
On a typical property, 20% to 40% of the depreciable basis moves into those shorter classes. Multifamily with heavy interior finishes and retail with significant site work tend to land at the higher end.
The study only works if it holds up. A defensible report is built on engineering analysis, documented cost allocations, and site inspections.
A cheap estimate that won't survive an audit is a liability. That makes the choice of cost segregation provider a relationship decision as much as a pricing decision.
You can also read: Multifamily Starts Hit 10-Year Low: What It Means for Sun Belt Investors.
"Placed in Service" Decides the Deduction
The rule that catches people is that the deduction depends on when the property is placed in service, not when you sign the contract.
The IRS defines that as ready and available for its intended use. Purchase date, invoice date, and delivery date don't count.
For a stabilized acquisition, closing and placing in service usually happen together. A value-add renovation is different. If units come back online in January, those improvements count in January.
A retail pad still waiting on its certificate of occupancy has not been placed in service.
In fast-moving markets like DFW, Austin, Houston, and Phoenix, this is where timing pays off.
Contractors with December capacity, lenders who can close before the holidays, and title teams who won't let a closing slip past year-end all affect the tax outcome. Late in the year, slow execution has a real cost.
You can also read: Insurance Is Now the Line Item That Kills Deals in 2026.
The Passive Loss Limit
Bonus depreciation creates large losses, but a loss only helps if you can use it. For most investors, rental losses are passive.
The $25,000 allowance for rental losses phases out between $100,000 and $150,000 of modified adjusted gross income.
Above that, if you don't qualify as a real estate professional, those losses are suspended and carried forward until you have passive income or sell the property.
That still has value, but it is not a cut to this year's tax bill. Investors who qualify for real estate professional status under Section 469 can use the losses against active income, including W-2 wages.
Qualifying means more than 750 hours a year, and more than half of your working time, spent in real property trades or businesses.
Also, you need to materially participate in the rental activities themselves, or elect to group them. Short-term rentals with average stays of seven days or less fall under separate rules, and material participation can open up similar treatment.
These rules are where good plans fail. Run your status and participation records past a CPA who works with real estate before you close a deal that depends on the deduction.
You can also read: Houston Multifamily Values Are Down 11%: Insurance Is the New Interest Rate.
Plan for the Exit at Acquisition
Accelerated depreciation comes with depreciation recapture. When you sell, the deductions you took on short-life components can be taxed as ordinary income. Investors who skip this step can be surprised by a large bill at disposition.
The fix is to plan the exit when you buy. A properly structured 1031 exchange can defer recapture along with capital gains, and many experienced operators use cost segregation and like-kind exchanges together over the life of a portfolio.
Your hold period, your expected tax bracket at sale, and the replacement strategy all matter, and all of them should be decided before the study is ordered.
Already own a property that never had a study?
A look-back study can catch up missed depreciation through a change in accounting method, without amending prior returns.
The applicable bonus rate depends on when you acquired the property, but the catch-up can still be substantial for buildings bought in the last several years.
You can also read: 100% Bonus Depreciation Is Permanent: What CRE Investors Need to Know.
The Team Matters More Than the Tactic
None of this is new information, and the tax code is available to everyone.
The investors who benefit are the ones who have a CPA who answers in October, a cost segregation firm that can schedule a site visit before Thanksgiving, a lender who closes on time, and a title partner who keeps the file moving through the holidays.
That network can't be built in the second week of December. It comes from relationships formed over months, through referrals from people who have worked with these providers, and conversations with members who were in the same position last year.
That is what Real Estate Forum (REF) is built for.
Our members include investors, CPAs, tax attorneys, lenders, title professionals, and the service providers who make year-end execution possible, across DFW and beyond.
If your fourth-quarter plan depends on people you haven't met yet, start now.
Join REF and build your network before the deadline.
NOTE: This article is for general information and is not tax advice. Consult a qualified CPA or tax attorney about your situation.