UK Cryptoasset Reporting Framework: first reports due

The Cryptoasset Reporting Framework (CARF) is an international standard of the Organisation for Economic Co-operation and Development (OECD). Under it, cryptoasset service providers collect tax information on their users and send it to their tax authority, which exchanges it with other countries (HMRC manual (external site)).

The UK applies CARF from 1 January 2026 and extends it to users resident in the UK. The first annual report, for 2026, goes to HM Revenue and Customs (HMRC) by 31 May 2027 (HMRC guidance (external site)).

Since 1 January 2026, reporting cryptoasset service providers (RCASPs) carry out tax due diligence on their customers and record transaction data (HMRC manual (external site)).

For a new user, the provider obtains a self-certificate, a signed statement of tax residence, before carrying out any transaction for that user. For users who were already customers, the deadline is 31 December 2026 (HMRC manual (external site)).

For an individual, the self-certificate gives name, date of birth, residence address, tax residence and a tax identification number (TIN) for each reportable jurisdiction. For UK residents the TIN is in most cases the National Insurance number (HMRC guidance (external site)).

A user who fails to give a valid self-certificate, deliberately or through lack of reasonable care, can face a penalty of up to GBP 300 (HMRC guidance (external site)).

Each year, the provider reports by 31 May on the previous calendar year (The Reporting Cryptoasset Service Providers Regulations 2025 (external site)).

As an example, a UK-resident user who opens an account in March 2026 and trades during the year appears in the provider's report for 2026. The provider files it between 1 January and 31 May 2027 (HMRC guidance (external site)).

The duty falls on RCASPs that serve users in the UK, including banks that offer cryptoasset services (HMRC guidance (external site)). The roles most directly concerned:

• Tax Associate: the annual report to HMRC and its 31 May deadline become a fixed task.
• KYC Analyst: onboarding of individual users includes the tax self-certificate before the first transaction.
• Corporate Onboarding Analyst (KYC): entity users give their own self-certificate, with details of the persons who control them.
• Periodic Review Analyst (KYC): pre-existing users without a valid self-certificate are followed up before 31 December 2026.

The legal basis is a statutory instrument made in 2025, the Reporting Cryptoasset Service Providers (Due Diligence and Reporting Requirements) Regulations 2025 (external site).

The dates are all confirmed. Due diligence starts on 1 January 2026, self-certificates of pre-existing users are due by 31 December 2026, and the first report window runs from 1 January to 31 May 2027 (HMRC guidance (external site)).

After 2027, a report is due by 31 May every year. HMRC then exchanges the data on non-UK residents with partner jurisdictions (HMRC manual (external site)).

Before CARF, international tax reporting by financial firms rested on the Common Reporting Standard (CRS), which covers financial accounts. HMRC consulted on CARF, on amendments to the CRS and on extending reporting to UK-resident users in the same exercise (HMRC consultation (external site)).

The domestic extension adds users resident in the UK to the reports that HMRC receives (HMRC policy paper (external site)).