CARF Reporting
CARF is an OECD tax reporting framework requiring crypto-asset service providers to collect user tax information and report certain crypto transactions to tax authorities. Implemented in the UK through HMRC regulations, it enables standardised reporting and international data sharing to improve tax transparency and compliance.
What’s the scope?
Entities in scope
Any Reporting Crypto Asset Service Provider (RCASP)Â required to report to HMRC, including UK and non-UK firms providing cryptoasset services to reportable users
Nexus
UK tax-resident users (reporting is triggered by the user’s tax residence, not where the platform is headquartered)
Activity
Facilitating in-scope cryptoasset transactions (e.g. crypto-to-fiat, crypto-to-crypto, transfers and certain in-scope payment transactions when crypto is used to pay for goods and services)
Deadline
Collect data from 1 Jan 2026. Submit by 31 May 2027.
Reporting frequency
Annual reporting
File format
Generate XML
Data fields needed
Accounts/wallets: User/ account ref + wallet address/ID for reportable crypto activity
- Individuals: Name, address, DOB, all tax residences, TIN per country (or valid reason code where not available)
- Corporates: Entity name, address, tax residence + TIN(s), plus controlling persons (same fields as for individuals)
- Transactions: Crypto-asset type + annual totals by category (crypto-to-fiat, crypto-to-crypto, transfers and retail payments)
Reporting considerations to keep in mind
User notice required
If a user/person is reportable, you must notify them their data will be reported to HMRC and may be shared internationally (by 31 Jan after their first reportable year)
HMRC registration
RCASPs must register with HMRC (by 31 May 2027, or 31 Jan after their first in-scope year, whichever is later)
Steps to submission
Here are the steps required to meet CARF reporting obligations.
Build customer communications
Notify reportable users of HMRC reporting + possible cross-border sharing.
Capture data + tag
Update your onboarding flow to capture tax residence + TINs (and reason codes) and tag UK reportable users + transaction categories (above) so reporting can be generated