Section 163(j) Business Interest Limitation: The 30% ATI Cap and OBBBA's EBITDA Restoration

If your business borrows money, there is a tax rule that can quietly turn a chunk of your interest expense into a non-deduction. It is called Section 163(j), and for tax years 2022 through 2024 it became dramatically harsher for asset-heavy companies—real estate operators, manufacturers, contractors, and anyone with significant equipment depreciation. Then the One Big Beautiful Bill Act (OBBBA) flipped the calculation back in the taxpayer's favor for 2025 and beyond.

If you have not revisited this rule since the law changed, you are probably leaving deductions on the table—or unknowingly walking into the limitation for the first time. Here is what every business owner, CFO, and tax preparer needs to understand right now.

What Section 163(j) Actually Does

Section 163(j) caps how much business interest expense you can deduct in a given year. The deduction is limited to the sum of three components:

1. Business interest income for the year
2. 30% of adjusted taxable income (ATI)
3. Floor plan financing interest expense (relevant mostly to auto and equipment dealers)

Anything above that ceiling is disallowed in the current year, but it does not vanish. The excess carries forward indefinitely as a separate tax attribute that you can deduct in a later year if your ATI grows or your interest expense drops.

The rule was rewritten by the Tax Cuts and Jobs Act in 2017 and now applies broadly. It is reported on Form 8990, which is required for almost any taxpayer who has business interest expense, a disallowed carryforward, or who receives an excess interest allocation from a partnership.

Who Is Actually Subject to It

Most businesses fall into one of three buckets: fully exempt, fully subject, or somewhere in between because of an election.

The Small Business Exemption

If your business is not a tax shelter and you meet the gross receipts test under Section 448(c), you skip Section 163(j) entirely. The threshold is the same one used for the cash method of accounting and the small business simplifications. The number is indexed for inflation each year:

• $25 million when TCJA was enacted
• $30 million for tax years beginning in 2024
• Approximately $31 million for 2025
• Adjusted upward each subsequent year

The test looks at the average annual gross receipts for the three prior tax years. Cross that line for three years running and you lose the exemption permanently—until your three-year average drops back below the threshold.

The Aggregation Trap

You cannot escape the limitation by splitting one business into five smaller ones. Section 448(c)(2) imports the aggregation rules from Sections 52(a), 52(b), 414(m), and 414(o). Roughly, that means:

• Parent-subsidiary controlled groups (one entity owns more than 50% of another)
• Brother-sister groups (five or fewer owners control overlapping percentages of multiple entities)
• Affiliated service groups
• Common control across non-corporate entities

If you and your spouse own three LLCs that together gross $40 million, the exemption is gone even if each LLC individually grosses $14 million. Family attribution rules can fold in receipts you did not realize counted.

The Tax Shelter Disqualification

Even a tiny business loses the small business exemption if it qualifies as a tax shelter under Section 461(i)(3). The most common trap here is the syndicate rule: any partnership or LLC where more than 35% of losses are allocated to limited partners or limited entrepreneurs in a given year is a syndicate—and a syndicate is a tax shelter for this purpose.

This catches a lot of real estate partnerships and investment LLCs that have a money-losing year. Have one bad year with most losses going to passive investors, and you can lose the small business exemption for that year regardless of how small you are.

Excepted Trades or Businesses

Three categories can elect or are mandated out of Section 163(j) regardless of size:

• Electing real property trades or businesses (development, construction, acquisition, rental, operation, management, leasing, brokerage)
• Electing farming businesses
• Regulated utilities (mandatory exception, not an election)

The election is irrevocable and comes with a meaningful cost: electing real property and farming businesses must use the Alternative Depreciation System (ADS) for nonresidential real property, residential rental property, and qualified improvement property. ADS recovery periods are longer (40 years for nonresidential, 30 years for residential rental, 20 years for qualified improvement property), and bonus depreciation is unavailable on ADS-depreciated property.

For a leveraged real estate operator with mostly building cost basis, the math often favors making the election. For a real estate business heavy in newly placed-in-service equipment or short-life improvements, the calculation is closer.

The 2025 Game-Changer: EBITDA Comes Back

Here is the change that matters most this year.

From 2018 through 2021, ATI was effectively EBITDA—earnings before interest, taxes, depreciation, and amortization. Starting in 2022, Congress let depreciation, amortization, and depletion drop out of the addback, shifting the calculation to EBIT. That single change tightened the deduction limitation for any capital-intensive business.

OBBBA permanently restored the EBITDA-based ATI calculation for tax years beginning after December 31, 2024. Depreciation, amortization, and depletion are once again added back when computing ATI.

A Concrete Example

Consider a contractor with $1,000,000 of taxable income before interest, $450,000 of depreciation, and $650,000 of business interest expense.

Under the EBIT rules (2022–2024):

• ATI = $1,000,000
• 30% of ATI = $300,000
• Plus interest expense already in taxable income = $650,000
• Deductible interest = approximately $495,000
• Disallowed and carried forward = $155,000

Under the EBITDA rules (2025 and later):

• ATI = $1,000,000 + $450,000 depreciation = $1,450,000
• 30% of ATI = $435,000
• Plus interest expense already in taxable income = $650,000
• Deductible interest = approximately $630,000
• Disallowed and carried forward = $20,000

That is a $135,000 swing in deductible interest in a single year, just from a calculation change. Multiply that across multiple years and you understand why CFOs at leveraged businesses are revisiting their projections.

The Capitalized Interest Wrinkle

For tax years beginning after December 31, 2025, OBBBA added a new rule: any business interest expense that is electively capitalized to property retains its character as interest and remains subject to Section 163(j). Translation—you cannot dodge the limitation by capitalizing interest into inventory or self-constructed assets. Plan accordingly when modeling out projects that rely heavily on construction-period interest.

How Pass-Through Entities Apply the Rule

The mechanics differ between partnerships and S corporations, and this catches many owners off-guard.

Partnerships and LLCs Taxed as Partnerships

The Section 163(j) limitation is computed at the partnership level. Any disallowed business interest expense is allocated to the partners as excess business interest expense (EBIE).

EBIE has unusual characteristics:

• It does not become a partner-level carryforward in the ordinary sense
• The partner cannot deduct it currently
• It is "released" only when the partnership later allocates the same partner excess taxable income or excess business interest income in a future year
• The EBIE allocation also reduces the partner's basis in the partnership interest immediately, even though the deduction is suspended

This creates a rare situation where a partner's basis is reduced today for a deduction they cannot use until possibly years later. For partners contemplating a sale of their interest with suspended EBIE, the rules around basis adjustments require careful planning.

S Corporations

S corporations apply the limitation at the corporate level as well, but with a critical difference: any disallowed business interest expense stays at the S corporation and carries forward as an entity-level attribute. Shareholders never receive an EBIE allocation. The self-charged interest rules also do not apply between an S corporation and its shareholders the way they do for partnerships.

This different treatment is one of the rare cases where S corporation status produces a meaningfully different tax outcome from partnership status, and it can be a planning factor when choosing entity form for a leveraged business.

Who Files Form 8990, Even When the Limitation Does Not Apply

Form 8990 is required even by some taxpayers who are not subject to the limitation:

• Any taxpayer with current-year business interest expense who is not exempt
• Any taxpayer carrying forward disallowed interest from a prior year
• Any pass-through entity that allocates excess taxable income or excess business interest income to its owners (even if the entity itself has no interest expense)
• Partners receiving EBIE allocations from partnerships

If you receive a Schedule K-1 that shows EBIE or excess taxable income, you generally need to file Form 8990 to track those attributes—even if your own business is nowhere near the limitation.

Practical Planning Moves for 2026

If you are a business with material interest expense, here are the questions to work through before year-end:

Reconfirm your small business status. Recalculate your three-year average gross receipts using the aggregation rules. Spouses, family members, and entities under common control all matter. If you crossed $31 million on a three-year average, you need to plan as if Section 163(j) applies.

Watch the syndicate trap. Run a projection of how losses will be allocated for the year. If a partnership or LLC is heading toward a loss year, model whether more than 35% of those losses will go to passive investors. If yes, you may temporarily lose the small business exemption that year.

Re-evaluate prior real property elections. Some businesses that elected out of Section 163(j) under the EBIT rules may regret that choice now that EBITDA is back. The election is generally irrevocable, but the IRS has issued narrow procedures permitting withdrawal in specific circumstances. If you elected out and now wish you had not, consult on whether any procedural relief applies.

Stress-test your debt covenants. A higher interest deduction means lower taxable income and potentially lower tax expense in your forecast. Lenders and investors using post-tax cash flow projections need updated numbers.

Review carryforwards. Disallowed interest from 2022, 2023, and 2024 is sitting on tax balance sheets at many capital-intensive companies. Some of that carryforward may finally be usable in 2025 because the EBITDA addback expanded ATI.

Coordinate with depreciation strategy. Higher depreciation now increases ATI (good) and accelerates deductions (good), but it also reduces future depreciation deductions in subsequent years (worse for future ATI). Bonus depreciation, Section 179, and ADS choices all interact with Section 163(j) in subtle ways. For example, bonus depreciation often beats Section 179 for taxpayers approaching the Section 163(j) limit, because Section 179 directly reduces taxable income while bonus depreciation produces depreciation that is added back into ATI.

Track everything that flows to and from your books. This is where many businesses lose money on Section 163(j)—not because they failed the calculation but because their underlying records did not cleanly separate business interest from investment interest, or current-year interest from carryforward attributes.

The Records Problem Behind the Rule

Section 163(j) is one of the most disclosure-intensive areas of corporate and pass-through tax. Form 8990 alone has multiple schedules tracking ATI components, current-year interest expense, business interest income, floor plan financing, partnership allocations, and carryforward attributes. The carryforwards are indefinite, which means a disallowed amount from 2022 can sit on your books for a decade, waiting to be matched against a year with sufficient ATI.

That requires bookkeeping that:

• Cleanly tags interest expense by source (term loan, line of credit, intercompany debt, capitalized lease, partnership debt)
• Distinguishes business from investment interest at the transaction level
• Tracks ATI components separately so you can rebuild your calculation if the IRS asks
• Carries Section 163(j) attributes (disallowed interest, excess taxable income, excess business interest income, EBIE) across years with full audit trails
• Survives bookkeeper turnover, accountant changes, and software migrations

Spreadsheets handle the math. They do not handle the decade-long memory or the audit trail.

Keep Your Tax Attributes Auditable from Day One

Section 163(j) is the kind of provision where good records compound in your favor for years. The disallowed interest you carry forward, the EBIE that gets released in a future year, the ATI components you needed three years ago to rebuild a calculation—these all live or die in your accounting system.

Beancount.io provides plain-text, version-controlled accounting that gives you complete transparency over every dollar of interest, every depreciation entry, and every basis adjustment. Your records are not locked in a proprietary database. They are human-readable text files you fully own, with every change tracked in git—exactly the audit trail you want when a tax attribute reaches back five or ten years. Get started for free and see why developers, finance professionals, and tax-conscious business owners are switching to plain-text accounting.