The OECD's Crypto Asset Reporting Framework (CARF) is now in effect, requiring the UK and over 40 other countries' crypto platforms to collect and report detailed user identity and transaction data to tax authorities. The rule takes effect from January 1, 2026, and mandates service providers to track user information, tax residency status, and complete transaction records. The first reports must be submitted to HM Revenue & Customs (HMRC) by May 31, 2027, covering transactions in 2026. Non-compliance, such as providing incorrect information or failing to pay taxes owed, may result in fines of up to £300, as well as late payment penalties of up to 100% of the unpaid tax amount.