Plain English
Even a perfectly arm's length interest rate on perfectly reasonable debt can still be partly non-deductible under these rules, because the limitation is not about pricing at all — it caps total net interest expense relative to the entity's earnings, usually around 30% of EBITDA, as a blunt anti-base-erosion tool that applies to third-party debt too.
Technical definition
Interest limitation rules restrict the deductibility of net interest expense to a fixed percentage of tax EBITDA (commonly 30%, as recommended under BEPS Action 4 and implemented via the EU Anti-Tax Avoidance Directive Article 4, or under US IRC §163(j)), operating independently of transfer pricing arm's length pricing rules and of any domestic thin capitalisation regime.
Why it matters
These rules can disallow interest deductions on entirely arm's length, third-party debt, meaning transfer pricing compliance alone does not guarantee full deductibility — treasury and tax must model the interaction of all three regimes together.
How it works in practice
- 01Calculate net interest expense (interest expense less interest income) for the period.
- 02Calculate tax EBITDA under the local definition, which can differ from accounting EBITDA.
- 03Apply the statutory percentage cap (commonly 30%) to determine the maximum deductible net interest.
- 04Disallow (or carry forward, where permitted) any excess above the cap.
- 05Coordinate the result with thin capitalisation and transfer pricing interest rate analysis for the same debt.
Worked example
ATAD 30% EBITDA cap in practice
An EU subsidiary has net interest expense of EUR 6m and tax EBITDA of EUR 15m. The ATAD cap limits deductible net interest to 30% of EBITDA, or EUR 4.5m, disallowing EUR 1.5m even though the underlying loans were separately benchmarked and priced at an arm's length rate. Many ATAD implementations allow a de minimis threshold (often EUR 3m) and a carry-forward of disallowed interest to future years, so the entity may recover part of the EUR 1.5m if EBITDA rises later.
Common mistakes
- Assuming arm's length pricing under Chapter X automatically ensures full deductibility.
- Missing jurisdiction-specific EBITDA add-backs or exclusions (e.g. group ratio escape clauses).
- Failing to track disallowed interest carry-forwards across years.
Audit red flags
- Net interest expense consistently near or above 30% of EBITDA.
- No modelling of the interaction between thin cap, transfer pricing and interest limitation rules for the same debt.
- Disallowed interest carry-forwards untracked or unreconciled.
Documentation & data
Documents to hold
- Annual interest limitation calculation with tax EBITDA workings.
- Carry-forward schedule for disallowed interest.
- Group ratio or escape clause analysis, if relied upon.
Data you need
- Local tax EBITDA definition and any add-backs.
- Full interest expense and income by entity.
- Group-wide leverage and interest data if a group ratio escape is used.
Who owns this internally: In-house tax owns compliance calculations; treasury and tax jointly model the impact on financing decisions.
Jurisdiction notes
- European Union
- ATAD Article 4 mandates a 30% EBITDA cap (or a de minimis EUR 3m threshold) across member states, with a group ratio escape available in most implementations.
- United States
- IRC §163(j) caps business interest deduction at 30% of adjusted taxable income, with the EBITDA-based calculation having tightened to an EBIT basis from 2022 onward.
- OECD (BEPS Action 4)
- Recommends a fixed ratio rule in the 10%–30% EBITDA range as a best-practice benchmark for domestic legislation.
Notes by role
CFOs & finance leaders
Model interest limitation exposure before executing large intercompany or third-party financings — it can materially change the after-tax cost of debt.
In-house tax teams
Track carry-forwards separately by entity; they are easy to lose track of across multi-year, multi-jurisdiction structures.
Frequently asked
- Do these rules apply to third-party bank debt too?
- Yes, in most jurisdictions the cap applies to net interest expense regardless of whether the lender is related or third-party.
- Can disallowed interest ever be used?
- Many regimes allow indefinite or time-limited carry-forward of disallowed interest to years with spare EBITDA capacity.
Sources & status
- Primary source
EU Anti-Tax Avoidance Directive (ATAD), Article 4
European Union, 2016
- Primary source
IRC §163(j)
US Congress, 2023
- Primary source
BEPS Action 4 Final Report
OECD, 2015
Reference material only, not advice on a specific fact pattern. Reviewed 2026-06-30.
Careers
How this shows up in the job
Distinguishing interest limitation rules from both thin cap and transfer pricing is one of the highest-value clarifications you can offer in a technical interview.
Careers in transfer pricing