Find out when and how to report to HMRC under the Cryptoasset Reporting Framework (CARF).
If you provide cryptoasset services in the UK, you must collect data and report it to HMRC.
This is because of rules called the Cryptoasset Reporting Framework (CARF).
You can subscribe to get email updates about Cryptoasset Reporting Framework guidance.
Information you need to report
You need to collect details of all of your users, but you only need to report on users who are tax resident in the UK or another country that is signed up to CARF rules.
You need to report these users’ details and a summary of their transactions.
If you have no information to report in a year, you do not need to submit a report.
How to create your report
Your data must be submitted in XML file format.
Each file can be up to 250MB — you can split your data into more than one file, if needed. It must not be a compressed zip file.
To create your XML file, you must use the:
How to submit your report
You’ll need to upload your report to our online service. It’s not live yet — we’ll update the guidance when it is.
When to report
You need to submit your first report by 31 May 2027, giving details for 1 January 2026 to 31 December 2026.
In future years you’ll also need to submit a report by 31 May, giving details for the previous calendar year.
If you do not follow the rules, we may charge you a penalty of up to £300 per user.
You could be charged a penalty if:
- you submit your report late
- if your report is inaccurate, incomplete or unverified
Find out about penalties (International Exchange of Information Manual: IEIM8000600).
More information
You can find detailed information about the Cryptoasset Reporting Framework:
You can also find out about international tax transparency standards on the OECD’s website.
If you have questions about the Cryptoasset Reporting Framework, you can email eoi.policy@hmrc.gov.uk.