IRC §163(j) business interest expense limitation: the 30%-of-ATI cap, the OBBBA permanent restoration of the EBITDA add-back, the small business gross-receipts exemption, and the real property and farming elections

IRC §163(j) limits how much business interest expense a business can deduct in a given year. For a leveraged business (one that carries substantial debt and pays substantial interest), the limitation can defer or restrict the deduction of interest that would otherwise reduce taxable income. The provision was a significant revenue-raiser in the Tax Cuts and Jobs Act of 2017, and its mechanics have shifted twice since then, most recently through the One Big Beautiful Bill Act (OBBBA) of 2025.

The core rule: business interest expense is deductible only up to the sum of business interest income, floor-plan financing interest, and 30% of the business's adjusted taxable income (ATI). Interest exceeding that limit is disallowed for the year and carried forward indefinitely.

The single most consequential variable in the calculation is how ATI is computed: specifically, whether depreciation, amortization, and depletion are added back. The OBBBA permanently restored the more generous "EBITDA" computation (with the add-back) for tax years beginning after December 31, 2024, reversing the stricter "EBIT" computation that had applied for 2022 through 2024. For capital-intensive businesses with substantial depreciation, this change substantially increases the amount of interest they can deduct.

The basic limitation

Per §163(j)(1), the deduction for business interest expense for a taxable year is limited to the sum of:

The taxpayer's business interest income for the year.

The taxpayer's floor-plan financing interest for the year (interest on debt used to finance the acquisition of motor vehicles held for sale or lease).

30% of the taxpayer's adjusted taxable income (ATI) for the year.

"Business interest expense" is interest paid or accrued on debt properly allocable to a trade or business. "Business interest income" is interest income properly allocable to a trade or business. The limitation applies to the net business interest expense (business interest expense in excess of business interest income), with the 30%-of-ATI cap providing the additional deductible capacity.

For most businesses without significant business interest income or floor-plan financing, the practical limitation is 30% of ATI. A business with $1 million of ATI can deduct up to $300,000 of net business interest expense; interest above that is disallowed and carried forward.

The ATI calculation and the EBITDA vs. EBIT history

ATI is the base against which the 30% limitation is applied. Per §163(j)(8), ATI starts with the taxable income for the year computed without regard to the §163(j) limitation, then adds back and subtracts certain items.

The critical question has been whether depreciation, amortization, and depletion are added back:

2018-2021 (EBITDA-based). Depreciation, amortization, and depletion were added back to taxable income in computing ATI. This produced a higher ATI (essentially a tax-basis EBITDA), and therefore a higher 30% limitation and more deductible interest. This was the more generous computation.

2022-2024 (EBIT-based). The add-back for depreciation, amortization, and depletion expired (under the TCJA's scheduled phase-down). ATI became a tax-basis EBIT figure, which is lower for businesses with substantial depreciation/amortization. The lower ATI produced a lower 30% limitation and less deductible interest. This tightened the limitation substantially for capital-intensive businesses (real estate, construction, manufacturing) that have large depreciation deductions.

2025 forward (EBITDA-based, permanent). The OBBBA, effective for tax years beginning after December 31, 2024, permanently restored the add-back for depreciation, amortization, and depletion. ATI returns to the tax-basis EBITDA computation. The restoration is permanent (not subject to another scheduled phase-down), which provides planning certainty.

The return to the EBITDA computation generally increases the amount of interest a business can deduct, particularly for businesses with large depreciation or amortization deductions. The change is especially relevant for capital-intensive industries and for businesses that have undergone acquisitions, where goodwill amortization can significantly affect ATI. The restoration also aligns with the OBBBA's permanent reinstatement of 100% bonus depreciation; the two provisions together favor capital investment.

Per the IRS Q&A guidance, the additions to taxable income in computing ATI include business interest expense, the net operating loss deduction, the §199A QBI deduction, and (for tax years beginning before 2022 and after 2024) depreciation, amortization, or depletion.

The small business exemption

Not every business is subject to §163(j). Per §163(j)(3), the limitation does not apply to a taxpayer (other than a tax shelter) that meets the gross receipts test of §448(c): average annual gross receipts for the three prior taxable years not exceeding the inflation-adjusted threshold (approximately $31 million for recent years).

The small business exemption is significant. A business under the gross-receipts threshold is entirely exempt from the §163(j) limitation; it can deduct all of its business interest expense without regard to the 30%-of-ATI cap. For the substantial majority of small businesses, the gross-receipts exemption means §163(j) doesn't apply at all.

The exemption is determined annually based on the prior three years' average gross receipts. A growing business that crosses the threshold becomes subject to §163(j) in the year after its three-year average exceeds the limit. Aggregation rules under §448(c) and §52 require related entities to be combined for the gross-receipts test, which prevents fragmenting a business into multiple entities to stay under the threshold.

The "tax shelter" exception to the exemption is important: a business that is a "tax shelter" (including a "syndicate," meaning an entity with more than 35% of losses allocable to limited partners or limited entrepreneurs) cannot use the small business exemption regardless of its gross receipts. This catches certain investment partnerships and loss-allocating structures.

The excepted trade or business elections

Certain trades or businesses can elect out of §163(j) entirely, at the cost of using slower depreciation:

Electing real property trade or business. A real property trade or business (development, construction, rental, operation, management, leasing, brokerage) can elect to be an "excepted trade or business" not subject to §163(j). The cost: the business must use the alternative depreciation system (ADS) for its real property, which has longer recovery periods and no bonus depreciation. The election is irrevocable.

Electing farming business. A farming business can similarly elect out of §163(j), with the same ADS depreciation tradeoff for certain property.

Regulated utilities. Certain regulated public utilities are excepted from §163(j) by statute (not by election).

The real property election is the most common. For a real estate business with substantial interest expense (which is typical, given the leverage in real estate), electing out of §163(j) avoids the interest limitation entirely. The tradeoff (ADS depreciation, which is slower and forgoes bonus depreciation) must be weighed against the benefit of full interest deductibility. With the OBBBA's restoration of the EBITDA-based ATI computation, some real estate businesses that previously elected out (to escape the stricter EBIT-based limitation) may find that the restored EBITDA computation provides enough interest capacity that the election (and its depreciation cost) is no longer necessary for new businesses. The election is irrevocable, however, so businesses that already elected out are locked in.

The indefinite carryforward

Interest disallowed under §163(j) is not lost; it is carried forward indefinitely and treated as business interest expense paid or accrued in the succeeding taxable year. Per §163(j)(2), the disallowed business interest expense carries forward without expiration.

The carryforward means the limitation defers the deduction rather than permanently denying it. A business that is limited in a low-ATI year can deduct the carried-forward interest in a later year when its ATI is higher (or when it has additional business interest income or floor-plan financing interest). The indefinite carryforward distinguishes §163(j) from provisions that permanently disallow deductions.

For pass-through entities, the carryforward rules are more complex. For partnerships, the §163(j) limitation is applied at the partnership level, and disallowed interest (called "excess business interest expense") is allocated to the partners, who carry it forward and can deduct it against excess taxable income allocated from the same partnership in later years. The partnership-level application and the partner-level carryforward create substantial complexity for partnership structures.

The OBBBA changes effective for 2026

In addition to the EBITDA restoration (effective for tax years beginning after December 31, 2024), the OBBBA made further changes effective for tax years beginning after December 31, 2025:

Capitalized interest coordination. The §163(j) limitation applies to business interest expense without regard to whether the taxpayer would otherwise capitalize that interest under an interest-capitalization provision. In other words, interest that is capitalized (added to the basis of property rather than deducted) is still subject to the §163(j) limitation. The exceptions: interest required to be capitalized under §263(g) (certain hedging transactions) and §263A(f) (interest during the construction of designated property) is not subject to this coordination rule. This change removes a planning technique (capitalizing interest to avoid the §163(j) limitation) for most interest.

CFC income exclusions. For multinational businesses, ATI is computed excluding certain controlled foreign corporation (CFC) income inclusions: Subpart F inclusions under §951(a), §956 inclusions, net tested income inclusions under §951A (formerly GILTI), the §78 gross-up, and certain §245A deductions. This affects multinational companies that previously increased their ATI (and thus their interest capacity) through CFC group elections.

Floor-plan financing expansion. Effective for tax years beginning after December 31, 2024, the definition of floor-plan financing interest was expanded to treat as a motor vehicle any trailer or camper designed to provide temporary living quarters for recreational, camping, or seasonal use and designed to be towed by or affixed to a motor vehicle. This benefits RV and camper dealers, whose floor-plan financing interest is now fully deductible (outside the 30%-of-ATI limit).

The IRS issued Fact Sheet FS-2025-09 (December 23, 2025) addressing the OBBBA changes to §163(j).

Coordination with other small business provisions

The §163(j) framework operates in coordination with several other Halstonberg small business provisions:

§168 MACRS depreciation and §179 bonus depreciation interact with §163(j) through the ATI computation; the restored EBITDA add-back means depreciation deductions increase ATI (and thus interest capacity), aligning the depreciation and interest provisions.

§199A QBI deduction is added back in computing ATI; the QBI deduction doesn't reduce the interest limitation base.

§469 passive activity loss rules interact with §163(j) for leveraged passive investments; both provisions can limit deductions for the same activity.

Choice of business entity affects how §163(j) applies; the partnership-level application with partner-level carryforward differs from the corporate-level application for C corporations.

Cost segregation studies increase depreciation deductions, which (under the restored EBITDA computation) increase ATI and therefore the interest deduction capacity.

Practical guidance

For businesses with substantial interest expense:

First, determine whether the small business exemption applies. If your average annual gross receipts for the prior three years are under the §448(c) threshold (approximately $31 million), you're exempt from §163(j) entirely (unless you're a "tax shelter"/syndicate). For most small businesses, this means §163(j) doesn't apply.

For businesses subject to §163(j), the restored EBITDA-based ATI computation (effective 2025) substantially increases your interest capacity if you have significant depreciation, amortization, or depletion. Model your interest deduction under the EBITDA computation; you may be able to deduct substantially more interest than under the prior EBIT-based rules.

For real estate and farming businesses, evaluate the excepted-business election. Electing out of §163(j) avoids the limitation but requires ADS depreciation (slower, no bonus depreciation). With the restored EBITDA computation, the election may be less necessary for new businesses; but the election is irrevocable, so businesses already elected out are locked in.

Track your disallowed interest carryforward. Interest limited in a low-ATI year carries forward indefinitely and can be deducted in a higher-ATI year. The carryforward is an asset; track it carefully.

For partnerships, understand the entity-level application and partner-level carryforward. The §163(j) rules for partnerships are complex; the excess business interest expense is allocated to partners with specific carryforward and deduction rules.

For tax years beginning after 2025, account for the capitalized-interest coordination rule and the CFC income exclusions. Interest you capitalize is still subject to §163(j) (except §263(g) and §263A(f) interest); and multinational businesses lose the ATI increase from CFC income items.

For RV and camper dealers, the expanded floor-plan financing definition means your floor-plan interest is fully deductible outside the 30%-of-ATI limit.

File Form 8990 to report the §163(j) limitation. The form computes the limitation, the disallowed interest, and the carryforward.

The §163(j) limitation is a significant constraint for leveraged businesses, but the OBBBA's permanent restoration of the EBITDA-based ATI computation substantially eases it for capital-intensive businesses. The small business exemption keeps most small businesses out of the limitation entirely; for businesses that are subject to it, the EBITDA computation, the carryforward, and the excepted-business elections are the key planning levers. Modeling the limitation under the current rules, and coordinating it with the depreciation and entity-structure decisions, is the foundation of effective interest-expense planning.