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Investor WorkspaceA little clarity for your next decision.
By Jerry Baker
The Opportunity Zone substantial improvement rule measures additions to a property's tax basis over a thirty-month period. The general test requires those additions to exceed the property's starting adjusted basis, while a lower threshold applies to certain wholly rural zones. This guide explains the calculation, the role of land, and the records needed to support a project.
Buying an old building inside a zone does not, by itself, make it qualifying Opportunity Zone property. Owned property generally must meet either the original-use test or the substantial improvement test, along with the other business-property rules. A zone address answers only one part of the review. [1]
The improvement test helps determine whether an existing asset has received enough new investment. It uses tax basis, not a broker's opinion of value or the owner's hope for a higher sale price. The difference matters because a building can rise in value without receiving any qualifying improvements.
The rule can apply to property held directly by a qualified opportunity fund, or QOF, and to property in a separate qualified opportunity zone business, or QOZB. Start by identifying the entity that owns the asset. That entity's purchase, basis, spending, and use records drive the review.
Passing the test also does not prove a project is a good investment. It does not measure rent demand, loan risk, the sponsor's skill, or whether the price is fair. Those questions belong beside the tax review, not beneath it.
Under the general rule, additions to basis during the thirty-month period must exceed the asset's adjusted basis at the beginning of that period. The word exceed is important. An amount exactly equal to the threshold does not satisfy the stated test. [1]
Suppose an existing building has a starting adjusted basis of $2 million. Assume the ordinary threshold applies and the costs in question are valid additions to its basis. The project needs more than $2 million of those additions within the allowed period.
A $1.9 million plan falls short. Exactly $2 million is not more than $2 million. A $2.1 million plan clears the arithmetic threshold, but only if the counted costs, timing, and other facts hold up.
This is sometimes described as doubling the building's basis. That phrase can be useful as a rough picture, but it can hide the strict greater-than rule. It can also confuse starting basis, later depreciation, and the specific costs counted in the test.
Use a written schedule that shows the starting adjusted basis, the threshold, and each addition. A single budget total is not enough. The tax preparer needs to know what each cost bought and when it entered the calculation.
Tax basis is the amount used to measure investment in an asset for tax purposes. Cost is often the starting point, with adjustments for items such as capital improvements and depreciation. The proper amount depends on the asset and the transaction. [2]
If one purchase includes land, a building, and equipment, the full price is not automatically the building's basis. The price must be allocated among the assets using a supportable method. The improvement test then follows the applicable property rules.
Assume a buyer pays $3 million for land and a used building. A supported allocation assigns $900,000 to land and $2.1 million to the building. Assume that $2.1 million is the building's adjusted basis when the chosen period begins.
The ordinary building threshold is more than $2.1 million, not more than the entire $3 million price. But the buyer cannot choose a high land value simply to make the test easier. The allocation needs evidence and should agree with the other tax records.
Closing costs may also affect basis, depending on what they are. Loan costs, current expenses, and property costs do not all receive the same treatment. Have the tax team classify them before putting them into the starting number or the additions schedule. [2]
When a qualifying purchase includes a building on land, the building test is based on additions to the building's basis. The rules do not require the underlying land to be separately substantially improved just because the building must meet the test. [1]
That does not turn idle land into an automatic qualifying investment. The property still must meet the business-use and other rules. A special limit applies when unimproved or minimally improved land is bought with no plan to improve it by more than an insubstantial amount within the stated period.
The regulation considers facts such as grading, clearing, cleanup, and buying related qualifying property that helps the business use the land. The review is broader than asking whether the owner poured a foundation.
A project should therefore answer two different questions. How is the building's improvement threshold calculated? And how does the land satisfy its own qualification rules? A favorable answer to the first does not replace the second.
Keep environmental work clear as well. Certain betterments to contaminated land may enter land basis under the rules. That is different from treating every cleanup invoice as an addition to the building. The records should follow what was actually improved.
The 2025 law reduced the improvement threshold for property in a zone comprised entirely of a rural area. IRS Notice 2025-50 explains how the change applies to the original zone designations. For determinations made on or after July 4, 2025, the required additions must exceed 50% of starting adjusted basis when the notice's conditions apply. [3]
For the hypothetical $2.1 million building, that means additions greater than $1.05 million. Exactly $1.05 million is not enough. Valid additions of $1.1 million would exceed this threshold, assuming the rural classification, timing, and other requirements are met.
| Hypothetical building | Starting basis | Required additions |
|---|---|---|
| Ordinary threshold | $2,100,000 | More than $2,100,000 |
| Eligible wholly rural zone | $2,100,000 | More than $1,050,000 |
Do not decide rural status from how a place looks. The definition excludes a city or town with more than 50,000 people and the specified urbanized area next to it. The notice applies a defined method and supplies a list of qualifying original-zone tracts.
A property on the edge of a large city is not necessarily rural under this rule. Nor does a lender's rural designation automatically settle the tax question. Check the exact tract, the applicable boundary set, and the governing guidance.
This lower project threshold is separate from the new rural-fund investor benefit for amounts invested after 2026. One concerns spending on property. The other concerns a later basis increase for a qualifying investment in a qualifying rural fund. Do not use one label as proof of the other. [4]
The improvement test uses a thirty-month period following the acquisition of the property. The chosen period and its opening basis need to be identified clearly. Do not assume that an investor's wire date starts the property's clock. [1] [3]
The investor's contribution, the fund's investment in a business, and the business's property purchase may happen on different dates. Each date can serve a different legal purpose. A timeline should name the entity and event beside every deadline.
Work backward from the planned completion date. Allow time for design, permits, bidding, delivery, construction, and final costs. A budget that meets the threshold only if every task finishes on its earliest possible date leaves little room for trouble.
Costs also need to be recognized under the correct tax rules. A signed contract, a deposit, and completed work are not always the same thing. Ask the tax preparer how the project's accounting method and capitalization rules affect the schedule.
Do not assume that the thirty-one-month working-capital safe harbor automatically extends the thirty-month improvement test. They address different issues. A project using both needs a separate analysis of each period and any specific relief that may apply. [5]
The legal measure is additions to basis. A cash outlay does not qualify merely because it is part of the project budget. IRS basis guidance distinguishes capital costs from expenses and explains how different items enter an asset's basis. [2]
A new roof, structural work, or a major building system may raise basis when properly capitalized. Routine operating costs and items currently deducted require a different analysis. These examples are starting points, not a substitute for classifying the actual invoices.
Separate construction from leasing, financing, and running the property. A lender may include all of those uses in one loan budget. The tax test may not. Interest, fees, wages, design costs, and permits need their own review under the applicable rules.
Also distinguish a forecast from a posted cost. The budget shows what management expects to spend. The basis ledger shows what the tax records support. Both are useful, but the forecast cannot replace the ledger when testing the result.
A practical cost report has a column for the vendor, work performed, date, amount, asset, and tax treatment. If a cost is excluded, retain the reason. That makes it easier to find gaps while there is still time to act.
Consider a used building with a $1 million starting basis under the ordinary rule. Management presents a $1.2 million project budget. That sounds like enough, but assume the tax review finds only $950,000 of valid additions to the building or other properly counted assets.
The other $250,000 covers items that, on these assumed facts, do not enter the improvement total. The project has spent more than $1 million in cash, but its counted additions are still only $950,000. It has not met the improvement threshold.
If the plan is revised to add another $100,000 of valid, timely basis additions, the counted total reaches $1.05 million. That exceeds $1 million. The revision works for this narrow arithmetic example only if the work, timing, and cost treatment are supported.
This example does not say that any particular expense is always excluded. It shows why the cost review should happen before the budget is approved. An early review may prevent an avoidable gap; a late review may reveal a gap after the money and time are gone.
Investors should also ask how a funding shortfall would be handled. Would the sponsor seek more equity, borrow more, reduce scope, or delay work? Those choices can affect both the improvement plan and the investment's risk. A tax threshold does not supply the money needed to reach it.
The rules allow certain purchased assets that would otherwise qualify on their own to count toward improving another asset. The assets must be in the same or a contiguous zone, serve the same business, and improve the older asset's function. Additional conditions apply. [1]
For example, a hotel renovation can involve the building as well as furniture, equipment, and other items used by the hotel. The rule can allow a coordinated review of those costs. It does not mean that any purchase in the neighborhood can be added to the hotel's total.
The regulation contrasts a hotel with a separate apartment building nearby. Improvements to the apartment building cannot simply be assigned to the hotel. Being one block away inside the same zone does not merge two unrelated improvement projects.
Choosing this treatment also changes how the counted new assets are treated under the original-use rule. The same dollars cannot be described however is most convenient at each step. Document the choice and its effects across the property review.
The older real property also must be improved by more than an insubstantial amount when this provision is used. Buying new equipment while leaving the building untouched is not a shortcut that the regulation promises to accept.
Specific rules permit certain buildings to be grouped for the improvement calculation. Buildings on a parcel described in one deed may qualify for this treatment. Contiguous parcels under separate deeds require more facts. [1]
For separate deeds, the rules look at operation by the same eligible entity, shared facilities or significant central business functions, and coordinated or dependent operations. Common ownership alone does not tell the whole story.
If a valid group has buildings with starting bases of $800,000 and $1.2 million, the combined starting amount is $2 million. Under the ordinary threshold, counted additions must exceed $2 million. The example assumes every grouping condition is met.
Without valid grouping, spending heavily on one building may not cure a shortfall on the other. Confirm the grouping before relying on the combined budget. Keep the deeds, site plan, operating facts, and written tax analysis together.
A sponsor's name for a campus is not the legal test. The documents and actual operations need to support the claimed group. This is especially important when buildings change tenants or business uses during the project.
Not every project needs the substantial improvement route. A newly built property that has not yet been placed in service may meet original use when the eligible buyer first uses it. Used equipment can also have original use in the zone if it was not previously used there in the required sense. [1]
Certain vacant properties have special original-use rules. The regulation distinguishes vacancy beginning before designation from vacancy beginning afterward. It also defines significant nonuse by reference to more than 80% of usable space, rather than a casual statement that the building was mostly empty.
A normal tenant turnover does not establish the needed vacancy history. Retain leases, utility records, site reports, and other evidence that supports the required period. The right proof depends on the facts.
Brownfields and certain property acquired from local government after an involuntary transfer have additional provisions. Those are specific paths with conditions. They should be reviewed as such, rather than folded into a blanket claim that distressed property always qualifies.
The rules for property acquired by lease do not simply copy the test for a purchased used building. They address lease timing, market-rate terms, use, related parties, and other conditions. Improvements made by a lessee can have their own original-use treatment. [1]
A related-party lease brings added rules, including a limit on advance rent and conditions for certain used personal property. A bargain purchase plan can create another problem for leased real estate. Calling an agreement a lease does not remove those questions.
Identify what the business owns, what it leases, and who owns each improvement. Then apply the right rule to each item. Mixing those categories can distort both the improvement review and the later asset test.
During the thirty-month improvement process, a special rule can provide qualifying treatment if the stated reasonable expectations and other conditions are met. That protection depends on a credible plan to complete the work and use the property as required. It is not a promise to overlook a failed project. [1]
Review the budget and schedule at regular milestones. If a permit is delayed, a contractor quits, or a cost is reclassified, update both the business forecast and tax analysis. The same event can affect cash needs, completion dates, and qualification.
Keep a margin above the minimum when reviewing the plan, while recognizing that extra spending is not always economically wise. The goal is a sound project that meets its rules. Spending money solely to cross a line can hurt investor returns.
For projects crossing into the new program, confirm the applicable acquisition and zone rules. Notice 2026-40 discusses intended transition proposals; it should not be read as a final blanket exception. Older regulations and forms must be considered with the enacted changes and later guidance. [4]
No. The improvement test concerns additions to tax basis, not growth in market value. Some property can meet original use instead. Where the ordinary improvement test applies, additions must exceed starting adjusted basis. [1]
No. The rule says additions must exceed the starting amount. For a $2 million starting basis, exactly $2 million in counted additions does not exceed it. The same strict comparison applies to the lower rural threshold. [3]
The special building rule measures improvements against the building's basis. Land is not added to that building threshold, but it must still satisfy its own business-property rules. The purchase allocation must be supported. [1]
For property covered by the current rural rule, additions must exceed 50% of starting adjusted basis. Verify the wholly rural classification and effective rules. The notice's original-zone list is not a general map of every rural location. [3]
No. A budget is a plan. The final test needs evidence of valid basis additions within the required period. Cost treatment, asset classification, dates, and the other qualification rules must also be checked. [1] [2]
Only when the applicable grouping or asset rules allow it. Being nearby or having one owner is not enough by itself. Deeds, parcel boundaries, shared operations, and the actual assets matter. [1]
Do not assume that. The thirty-one-month business cash safe harbor and thirty-month property improvement test serve different purposes. The advisors should review each timeline and any specific relief separately. [1] [5]
The owner's tax and legal advisors should review the basis, spending, property facts, and governing rules. Investors can ask for the process and supporting reports. An educational example is not an opinion that a particular project qualifies.
Educational information, not an offer or a personal tax, legal, or investment recommendation. Examples are hypothetical and omit stated adjustments. Tax treatment depends on your facts and current law. Review your transaction with your CPA, attorney, and qualified intermediary. Real estate investments can lose value and may be illiquid.
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