IHTM25533 - AR/BR 100% relief allowance: transfer of unused allowance - how to make the claim

The personal representatives must make a formal claim to transfer any unused 100% relief allowance from the estate of the deceased’s spouse or civil partner.   

The claim is made using form IHT437, which is one of the supplementary schedules to the IHT400.   

If the first spouse or civil partner died before 6 April 2026 the personal representatives should tick yes at box 6. The full 100% relief allowance is transferable and no further information is required.   

For deaths on or after the 6 April 2026 the personal representatives should include the following documents from the first death   

  • A copy of the grant of representation (confirmation in Scotland)- or if no grant was taken out, a copy of the death certificate,   

  • If the spouse or civil partner left a will, a copy of the will,   

  • A copy of any Instrument of Variation or similar document that changed who inherited the estate.    

If on the first death all assets were transferred to the spouse or civil partner, and there were no chargeable transfers of property that would have qualified for 100% agricultural or business property relief within seven years of death, then full 100% relief allowance is transferable and no further information is required.   

If there were chargeable transfers against which 100% business or agricultural property relief was claimed the personal representatives will need to supply details of any property that would have qualified for the 100% agricultural or business relief allowance in the estate of the spouse or civil partner.    

Where the time limit (IHTM25534) is approaching, you may allow the personal representatives to make a provisional claim if they are having difficulty getting all the documents.  They should complete Form IHT437 so far as they are able and identify what is outstanding and why.  In these circumstances, you can help the claimants by telling them that  

  • a copy of a grant of representation or Confirmation and copy Wills are available via the GOV.UK Website  

  • a copy of the death certificates is available from the General Register Office (for England & Wales, for Scotland, and for Northern Ireland).