HMRC letter codes · One-to-many letters
CIHT1MMLetter to agents about cryptoassets in Inheritance Tax returns
Published by its source on 19 December 2025. A date in the letter that has passed stays passed: what a passed date means.
Last reviewed 14 October 2026 · How Tax Letters checks its facts
In short
HMRC's letter CIHT1MM is headed “Please make sure your clients’ Inheritance Tax returns include details of their cryptoassets”.
“CIHT1MM … Please make sure your clients’ Inheritance Tax returns include details of their cryptoassets”
ICAEW: HMRC letter CIHT1MM, as published with its tax news item · checked 14 October 2026
Information, not advice: this page reports what HMRC, GOV.UK and the bodies named publish about CIHT1MM. Each fact has its source and the day it was checked beside it.
When HMRC sends it
ICAEW said, in the news item with HMRC's letter CIHT1MM, that HMRC was writing to agents who had previously submitted inheritance tax (IHT) returns to raise awareness of the requirement to account for IHT on cryptoassets.
“HMRC is writing to agents who have previously submitted inheritance tax (IHT) returns to raise awareness of the requirement to account for IHT on cryptoassets.”
ICAEW: Agents may be overlooking IHT on cryptoassets · checked 14 October 2026
What it asks
HMRC's letter CIHT1MM asks the agent to check with clients whether they hold any cryptoassets and to make sure IHT returns contain details of those cryptoassets on the IHT400 (‘IHT Account’).
“Please check with your clients, including estates personal representatives, to confirm whether they hold any cryptoassets. … Please make sure IHT returns contain details of those cryptoassets on the IHT400, ‘IHT Account’.”
ICAEW: HMRC letter CIHT1MM, as published with its tax news item · checked 14 October 2026
HMRC's letter CIHT1MM says that if a previous IHT return is incorrect it will need to be amended, and asks for OTM000752 to be quoted in the cover letter with the Corrective Account.
“If you find that a previous IHT return is incorrect, you or the personal representative will need to amend it. Please quote OTM000752 in the cover letter with the Corrective Account.”
ICAEW: HMRC letter CIHT1MM, as published with its tax news item · checked 14 October 2026
Free help and HMRC contacts
HMRC's letter CIHT1MM points to GOV.UK, search “Inheritance Tax: Corrective Account”, and gives the phone number 03000 523 040.
“For more information about this, go to GOV.UK and search ‘Inheritance Tax: Corrective Account’. … call us on 03000 523 040”
ICAEW: HMRC letter CIHT1MM, as published with its tax news item · checked 14 October 2026
Free help first
These routes are described by GOV.UK, TaxAid and Citizens Advice themselves.
- HMRC's extra supportHMRC offers extra support if your health condition or personal circumstances make it difficult to contact HMRC, for example a mental health condition, financial hardship or being treated in hospital.
- Someone to deal with HMRC for youYou can authorise a friend, relative or voluntary organisation to talk to HMRC for you and help you fill in forms.
- TaxAidTaxAid helps people with tax problems who cannot pay for advice. Tax Help for Older People merged with TaxAid in July 2025.
- Citizens AdviceCitizens Advice gives confidential advice online, over the phone and in person, for free.
- ICAEW: HMRC letter CIHT1MM, as published with its tax news item (checked 14 Oct 2026)
- ICAEW: Agents may be overlooking IHT on cryptoassets (checked 14 Oct 2026)
- GOV.UK: Get help from HMRC if you need extra support (checked 7 Oct 2026)
- GOV.UK: Appoint someone to deal with HMRC on your behalf (checked 7 Oct 2026)
- TaxAid: About us (checked 8 Oct 2026)
- Citizens Advice: About us (checked 7 Oct 2026)