UK forces crypto exchanges to hand over transaction data under OECD CARF

The UK has begun collecting full crypto transaction data from exchanges serving UK-linked users under the OECD’s Cryptoasset Reporting Framework (CARF). From 1 January 2026, HM Revenue & Customs (HMRC) requires exchanges to report complete histories including buy/sell prices, proceeds, realised gains/losses, cost basis and users’ tax residency. The UK is among the initial 48 jurisdictions implementing CARF; over 75 jurisdictions have signed up globally. Reporting will expand in stages: other financial centres (Hong Kong, Switzerland, Singapore, UAE) will start in 2027, the US in 2028, and automatic cross-border exchange of CARF data is expected from 2029 with bilateral sharing to start earlier with many jurisdictions (EU states, Brazil, South Africa, Cayman Islands, Channel Islands). HMRC has already ramped up enforcement — issuing 65,000 crypto warning letters in 2024–25 and adding a dedicated crypto section to self-assessment tax forms. Tax guidance clarifies disposals that trigger reporting: selling for fiat, token swaps, spending crypto and most gifts. Capital gains above £3,000 may be subject to Capital Gains Tax; frequent or business-like trading could be treated as income for income tax and national insurance. Tax advisers urge traders to reconcile records, confirm residency status, review past undeclared disposals and consider voluntary disclosure to mitigate penalties. For traders: ensure accurate cost-basis tracking, maintain clear records of disposals and receipts, and file self-assessments by 31 January to avoid penalties. Primary keywords: crypto tax, HMRC, CARF, crypto reporting, tax compliance.