An investor still holding a qualifying investment in a pre-2027 QOF on December 31, 2026 includes the excess of the lesser of the deferred gain not already included or the interest's fair market value over basis (Notice 2026-40 §4.01). Cost segregation of fund property placed in service in 2026 can add depreciation to that return, within passive-activity and outside-basis limits.
What actually happens on December 31, 2026
An earlier inclusion event, such as a sale, already triggered that gain for other investors. Treasury's Office of Tax Analysis tracked more than $75 billion of deferred gains sitting in Qualified Opportunity Funds at the end of 2024, across roughly 12,800 funds and 41,000 investors. That is the bill, it arrives on the 2026 return, and for a great many of those investors a cost segregation study on the property they already own is the most overlooked way to meet it.
The uncomfortable part, and the reason this is being written about now, is that the tax is not triggered by a sale. It is tied to the gain from the original investment, which means an owner can face a real cash obligation without having sold the Opportunity Zone asset and without any transaction generating the money to pay it. Higher borrowing costs have made the obvious answer, refinance and pay from proceeds, harder than it looked in 2019 - which is exactly why the deduction a cost segregation study can put on the same return deserves more attention than it is getting.
The coverage so far, including The Real Deal's summary of the Wall Street Journal reporting, has focused on two responses: hunting for cash, and re-examining appraisals. Both are correct. Both are also incomplete, because there is a third lever sitting inside the property itself, and cost segregation is the discipline that finds it.
The appraisal angle, named properly
Funds are scrutinising property valuations right now, and it is worth understanding exactly why rather than treating it as general caution.
Under IRC §1400Z-2(b)(2), the amount included in income is the lesser of the originally deferred gain or the fair market value of the QOF investment on the inclusion date, reduced by basis in the investment. So if a project is worth less on December 31, 2026 than the gain that went into it, the includible amount can be lower than the deferred figure. That is not a loophole; it is how the statute is written, and it is why an appraisal has suddenly become a tax document rather than a lender document. The line-by-line mechanics of the December 31 inclusion work the same computation from the preparer's side, including the vintage basis classes that reduce the includible amount.
Two conditions travel with that. It requires a well-supported valuation, prepared for this purpose and documented. And it cuts the other way for successful projects, because a fund whose asset appreciated does not get to include less.
The lever the coverage is missing: the deduction is already in the building
Here is what almost nobody is saying. The recognized deferred gain lands on the same 2026 return that reports the operating results of the Opportunity Zone property. If that property has been through a cost segregation study and is placed in service, the accelerated depreciation the study produces lands on that return too.
A cost segregation study reclassifies parts of a building out of the 27.5- or 39-year line and into 5-, 7- and 15-year property: the finishes, fixtures, specialty electrical, appliances, paving, landscaping and site work that a building's single line item quietly contains. In an Opportunity Zone deal, which is very often new construction or substantial improvement, there is usually a great deal of it. A multifamily property of five or more units typically reclassifies 20–30% of the depreciable basis (purchase price plus construction costs, less land), a planning band rather than a promise.
Whether those deductions can actually be applied against the recognized gain is fact-specific, and it is the question to put to your advisor rather than assume. But the shape is straightforward: a large first-year deduction arriving in the same year as a dated tax liability is a materially different position from that deduction arriving in 2027, when the bill has already been paid.
Why the basis question decides whether any of this lands
There is a mechanic underneath this that catches people, and it is worth stating plainly because it is the difference between a usable deduction and a suspended one.
A QOF interest funded with deferred gain begins with a $0 tax basis under IRC §1400Z-2(b)(2)(B), and §704(d) limits deductible partnership losses to a partner's basis. On its own that would strand the deductions a study produces. What usually rescues it is §752: a partner's share of partnership debt counts toward outside basis, and Opportunity Zone real estate commonly runs 50-70% financed, which normally creates the capacity to absorb front-loaded deductions.
Normally is not always. It is something to establish rather than assume, and it is one of the questions worth resolving before December rather than in April. We walk through that arithmetic in the zero-basis mechanics.
The trap in selling a loser
One response being discussed is disposing of underperforming assets to harvest losses against the gain. That works arithmetically, and it carries a cost that is easy to underweight.
Exiting an Opportunity Zone investment before the ten-year mark forfeits the exclusion that makes the whole structure worth doing. Reaching ten years on a qualifying investment, selling the fund interest and electing the fair market value step-up under IRC §1400Z-2(c) eliminates the tax on post-investment appreciation and eliminates the recapture that would otherwise claw back accelerated depreciation on that sale: the §1245 ordinary recapture on the reclassified 5- and 7-year property, the §1250 ordinary recapture of depreciation taken above straight-line on the 15-year land improvements, and the unrecaptured §1250 gain on the shell and land improvements, taxed up to 25%.
That is the point most worth holding onto here. Cost segregation inside an Opportunity Zone held to year ten, with the §1400Z-2(c) election made on a sale of the qualifying fund interest, is not a timing benefit at all, it is a permanent one, because on that sale there is no gain left for recapture to attach to; if the fund sells the property instead, a separate election under Treas. Reg. §1.1400Z2(c)-1(b)(2)(ii) is available to partnership and S-corporation funds only. Selling in year seven to cover a 2026 tax bill trades a permanent benefit for a temporary one. Sometimes that is still the right call. It should be a decision made with the number in front of you, not a reflex.
What to do between now and December
If you hold a pre-2027 OZ investment: establish three things. Whether the property has had a cost segregation study and, if not, whether it is placed in service such that one would land on the 2026 return. Where the fund is taxed as a partnership, establish what your outside basis in it is, including your §752 share of its debt. And what a well-supported December 31 valuation shows under the §1400Z-2(b)(2) lesser-of rule.
On timing: preparing the study is not the constraint. Assembling construction documents, confirming the basis position and getting the treatment reviewed is what consumes the calendar, which is why September is a better month for this conversation than December. Start the cost segregation study early so the depreciation side is sized before that work starts.
And if you are weighing a new investment: anything funded from 2027 onward is governed by the rewritten OBBBA rules, a rolling five-year deferral rather than a fixed date, with a 10% basis step-up at five years or 30% for a Qualified Rural Opportunity Fund. Our Opportunity Zone cost segregation page sets out how the two regimes interact across a full hold.
Related reading for investors holding through a partnership rather than directly: K-1 gain timing and the pass-through election window for OZ limited partners and the death-transfer exception that preserves OZ status instead of triggering the deferred gain.
The fixed Opportunity Zone and return dates from December 31, 2026 through 2028, each with its primary source, are on the Opportunity Zone and cost segregation calendar.
Frequently Asked Questions
Why do I owe tax on my Opportunity Zone investment if I have not sold anything?
Because the deferred gain has its own deadline, separate from the OZ asset. Under the original TCJA rules the gain you rolled into a Qualified Opportunity Fund is recognized on the earlier of an inclusion event or December 31, 2026, regardless of whether the fund's property has been sold. That is why investors are facing cash obligations with no transaction to fund them, and why 2026 planning started well before year-end for most funds.
Can a cost segregation study help me pay the 2026 deferred gain bill?
It can in the right circumstances, which is precisely why the timing matters. A cost segregation study front-loads depreciation into the placed-in-service year by reclassifying property into 5-, 7- and 15-year classes, and if that year is 2026 the deductions land on the same return that reports the recognized deferred gain. Whether they can be used against it depends on your passive-activity position and, where the fund is taxed as a partnership, your outside basis including your §752 share of its debt, so it is a question to put to your advisor with specifics rather than a general rule to rely on.
My project is worth less than what I put in. Does that reduce the tax?
It can. Under IRC §1400Z-2(b)(2) the amount included is the lesser of the originally deferred gain or the fair market value of your QOF investment on the inclusion date, reduced by your basis in the investment. A project that has declined in value can therefore produce a smaller inclusion than the gain originally deferred, which is why funds are scrutinising appraisals this year. It requires a well-supported valuation prepared and documented for that purpose.
Should I sell an underperforming OZ asset to offset the gain?
It is a real option with a real cost, and it should be modelled rather than assumed. Selling before the ten-year mark forfeits the §1400Z-2(c) fair market value election, which is what eliminates both the tax on appreciation and the recapture of accelerated depreciation on a sale of the qualifying fund interest. In other words a sale to cover the 2026 bill converts a permanent benefit into a temporary one, so the comparison is between the tax saved now and the exclusion given up later.
Does the ten-year exclusion cover depreciation recapture?
After a ten-year hold on a qualifying investment and with the §1400Z-2(c) fair market value election made on a sale of the fund interest, yes, there is no gain remaining for recapture to attach to on that sale, which covers the §1245 ordinary recapture on reclassified 5- and 7-year property, the §1250 ordinary recapture of depreciation taken above straight-line on 15-year land improvements, and the unrecaptured §1250 gain on the structure. Both conditions carry that answer. If the fund sells the property instead, a separate election under Treas. Reg. §1.1400Z2(c)-1(b)(2)(ii) applies to partnership and S-corporation funds, and a corporate fund has no such election. Exit before year ten, or fail to make the election, and recapture behaves entirely normally.
Is it too late to commission a cost segregation study for the 2026 tax year?
It is not too late while the 2026 return is unfiled: a cost segregation study on a property placed in service in 2026 can still be finished before that return is filed and claimed on it (an extension is an extension of time to file, not to pay), and the practical constraint is assembling AIA pay applications, invoices and drawings and getting the position reviewed, not preparing the study itself. For a property the owner placed in service in an earlier tax year, a look-back study applies. Under the automatic change procedures of Rev. Proc. 2015-13 and section 6.01 of Rev. Proc. 2025-23, the missed depreciation is claimed on Form 3115 with no amended returns when the property has been depreciated on two or more filed returns, or on one filed return if the taxpayer placed it in service in the tax year immediately before the year of change (the year of the return the Form 3115 is filed with), and the taxpayer still owned the property at the start of the year of change and meets the other eligibility rules.
