The hybrid mismatch rules in Part 6A of the Taxation (International and Other Provisions) Act 2010 stop companies getting a tax advantage when two tax systems treat the same payment, entity or branch differently. Where a payment is deducted in one country but never taxed as ordinary income in another, or the same expense is deducted twice, the rules cancel the mismatch, usually by denying the deduction and sometimes by taxing the receipt instead.

What is a hybrid mismatch?

A hybrid mismatch arises because countries classify things differently. One country may see an instrument as a loan and the other as shares. One country may treat an entity as a taxable company while another looks through it to its owners. A permanent establishment may be treated as taxable in neither the head office country nor the branch country. The result is either:

  • a deduction and non inclusion mismatch (often written D/NI), where the payer gets a deduction but the payee is not taxed on the receipt as ordinary income; or
  • a double deduction mismatch (DD), where the same expense is deducted in two countries.

The UK rules are based on the OECD recommendations under Action 2 of the Base Erosion and Profit Shifting (BEPS) project, but HMRC says they are deliberately broader in some areas, for example by covering permanent establishments and hybrid entities in territories with no corporate income tax (INTM550020). They work whether or not the other country has adopted equivalent rules.

When did the rules start and who do they affect?

Part 6A was inserted by section 66 and Schedule 10 of Finance Act 2016 and applies to deductions arising or accruing on or after 1 January 2017 (INTM550070). There is no grandfathering, so instruments issued before that date are caught for payments after it. Earlier arrangements fell under the old anti arbitrage rules.

The rules only apply to companies within the charge to corporation tax, either as payer or payee. In practice they bite on groups with cross border structures, but most chapters only apply where the parties are connected or the arrangement is structured:

  • Related persons: in the same control group, or where one has a 25% investment in the other or a third person has a 25% investment in both (section 259NC, INTM550610).
  • Control group: consolidated for accounting purposes, meeting the transfer pricing participation condition, or meeting a 50% investment test (section 259NB).
  • Structured arrangement: an arrangement it is reasonable to suppose is designed to secure the mismatch, or whose terms share the economic benefit of the mismatch between the parties (section 259CA(7)). This brings unrelated parties into scope.

The tests turn on relationships and on how the arrangement is designed, not on the size of the company, so an owner managed company with an overseas parent or subsidiary should still check whether a chapter applies.

Which arrangements do the rules cover?

The legislation is split into chapters, each aimed at one type of mismatch (INTM550090):

Chapter Mismatch Primary response
3 Financial instruments (D/NI) Deny the payer’s deduction
4 Hybrid transfers, such as repos and stock loans (D/NI) Deny the payer’s deduction
5 Hybrid payer (D/NI) Deny the payer’s deduction
6 Transfers by a UK permanent establishment (D/NI) Deny the deduction to the UK permanent establishment
7 Hybrid payee (D/NI) Deny the payer’s deduction
8 Multinational payee (D/NI) Deny the payer’s deduction
9 Hybrid entity (DD) Deny the investor’s deduction
10 Dual territory, including dual resident companies (DD) Deny the deduction
11 Imported mismatches Deny the payer’s deduction

Chapter 11 deals with mismatches that arise entirely between two other countries but are funded through a payment from the UK as part of the same overall arrangement. Without it, a group could route a mismatch through a third country to avoid the rules (INTM550040).

How are mismatches cancelled?

The rules use a primary response and a secondary, or defensive, response (INTM550020):

  • For a deduction and non inclusion mismatch, the primary response is to deny the deduction to the payer. If the payer’s country does not do that, the secondary response is to tax the receipt as ordinary income of the UK payee.
  • For a double deduction, the primary response is to deny the deduction to the parent or investor. If the investor’s country does not do that, the deduction is denied to the hybrid entity or permanent establishment.

Only the mismatch is counteracted, not the whole payment. If the payee is taxed on part of the receipt, only the untaxed excess is disallowed.

Timing differences and dual inclusion income

A payment is not treated as untaxed simply because the payee recognises it later. Under section 259CC(2), for financial instruments the payee’s taxable period counts as permitted if it begins before the end of 12 months after the end of the payment period, or later if it is just and reasonable. For double deductions, a deduction denied to a UK hybrid entity can still be set against dual inclusion income, meaning income taxed in both countries, and any unused amount is carried forward against future dual inclusion income (section 259IC(4) and (5)). If HMRC is satisfied there will be no further dual inclusion income, the stranded deduction can be released (section 259IC(6)).

What are the common examples?

Hybrid financial instrument

A UK subsidiary issues an instrument to its overseas parent. The UK treats it as debt and allows the coupon as interest under the loan relationship rules. The parent’s country treats it as equity and exempts the coupon as a dividend. That is the textbook deduction and non inclusion case described at INTM550030, and Chapter 3 denies the UK interest deduction.

Hybrid entity

A UK limited liability partnership is transparent for UK tax but may be treated as an opaque company by the country where its members live. A payment to the LLP can then be taxed in neither place, because each country thinks the other will tax it (INTM550030). Chapter 7 deals with this hybrid payee case.

Hybrid payer

A UK company that a foreign parent’s country treats as transparent pays interest to the parent. The UK allows a deduction but the parent’s country disregards the payment because, in its eyes, the company is part of the parent. Chapter 5 applies where the payer is a hybrid entity as defined in section 259BE (INTM553010).

Hybrid transfer

Shares are sold on terms that they will be returned after 12 months, and a dividend is paid during that time. One country treats the buyer as owner of the dividend, the other treats the seller as still owning it in substance. This can create a deduction and non inclusion outcome, covered by Chapter 4 (INTM550030).

How does a worked example look?

Illustration only. UK Co is wholly owned by Parent, resident overseas. In its accounting period UK Co pays £100,000 on an instrument that the UK treats as a loan. Parent’s country treats the instrument as shares and exempts the receipt. UK Co and Parent are related, so Condition D in section 259CA(6) is met. Under the primary response UK Co adds back the £100,000 in its corporation tax computation. If instead Parent’s country taxed £40,000 of the receipt as ordinary income within the permitted period, only the £60,000 excess would be disallowed.

How do the rules fit with other corporation tax rules?

The hybrid rules sit alongside, not instead of, other corporation tax rules, and HMRC explains the interaction at INTM550080 and INTM550085:

  • Transfer pricing. You cannot choose to apply either transfer pricing or the hybrid rules, or apply them in whichever order gives the better answer. Transfer pricing is applied taking the hybrid rules fully into account, and the hybrid rules are then considered again on the transfer pricing outcome.
  • Corporate interest restriction. HMRC expects the hybrid rules to be applied before the corporate interest restriction.
  • Foreign CFC charges. An amount taxed under another country’s controlled foreign company charge can count as ordinary income in some cases (section 259BD).
  • Withholding tax. Withholding tax paid on a payment is ignored when deciding whether a mismatch exists (section 259B(3A), INTM550095).

What mistakes come up most often?

  • Assuming the rules only apply to large groups. The conditions turn on relationships and structures.
  • Looking only at the UK treatment. The rules ask how the other country treats the payment, so you need evidence of the foreign tax position.
  • Forgetting structured arrangements. Pricing that shares the tax benefit with an unrelated lender can bring the arrangement into scope.
  • Disallowing the whole payment rather than only the mismatch, or ignoring the permitted period for late recognition.
  • Losing track of restricted deductions carried forward against future dual inclusion income.

HMRC says the hybrid rules contain no priority order with other legislation, so companies need to consider all relevant rules as part of their self assessment (INTM550080). The working papers behind the CT600 should show which chapters were considered and why each does or does not apply, because that is what HMRC will ask for in an enquiry.

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Reviewed by Christine Anderson, Broker, Solar Protect. Last reviewed 19 October 2026. Part of Accountapedia, the Solar Protect guide to UK tax and accounting. This page is general information, not personalised advice.