Further information — next steps, further questions and legislation (part 7)
Published 17 December 2025
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This publication is available at https://www.gov.uk/government/publications/help-with-imported-hybrid-mismatches-gfc16/further-information-next-steps-further-questions-and-legislation-part-7
Next steps
What to do if you have made an error
Due to a greater awareness of the imported hybrid mismatch rules, businesses may identify areas where they need to adjust their filed return to correctly reflect these rules.
We encourage businesses to correct any errors after reading these guidelines. Doing so manages exposure to adjustment and potential penalties under enquiry.
Where you discover an error in calculating the tax arising from imported hybrid mismatch rules, you must:
- check if the tax paid in earlier years is also likely to have been incorrect
- recalculate the liability for the year or years in question
The process for bringing your tax affairs up to date depends on whether the affected returns are within time for amendment:
- where you are within time to make an amendment, amend the return to reflect the counteraction under Chapter 11 hybrid mismatch rules — where you have a Customer Compliance Manager (CCM), inform them of the changes
- where you are not within time to make an amendment, you can make a voluntary disclosure — where you have a CCM, copy them into the email
- in both cases include the GfC reference number GfC16 in the amendment or disclosure
Further questions
If you have feedback or questions about these guidelines you can email us at: ccgguidelinesforcompliance@hmrc.gov.uk.
Include the GfC16 reference number in the subject line. Copy your CCM into the email if you have one.
Read about the risks of corresponding with HMRC by email.
Legislation and guidance
These guidelines are HMRC compliance expectations regarding Chapter 11 (‘Imported Mismatches’) of Part 6A TIOPA 2010 (‘Hybrid and Other Mismatches’). These guidelines refer to this as the imported hybrid mismatches rules. They do not address the core hybrid rules at Chapters 3 to 10 of Part 6A, nor the targeted anti-avoidance rule at Chapter 13.
These guidelines are not standalone and should be read alongside HMRC guidance relating to imported hybrid mismatches within its International Manual INTM550000 to INTM561700. Specifically, INTM559000 – Hybrids: imported mismatches (Chapter 11) provides guidance on Hybrids: imported mismatches.