HMRC

HMRC is the UK tax authority — and the primary regulator FintechPays cites in every UK crypto-tax review. The UK’s crypto-tax regime is more technically demanding than the US equivalent: HMRC applies Section 104 pooling (same-asset assets average into one “pool”), the 30-day rule (acquisitions within 30 days of a disposal can’t enter the pool — they match the disposal directly), and the bed-and-breakfast rule (the 30-day rule’s predecessor, still relevant for transactions before 6 April 2008 and for some derivative interpretations). Affiliate creators promoting crypto-tax tools to UK audiences must explain these rules accurately; getting them wrong in a comparison article is the single most cited error in our editorial corrections log.

HMRC also publishes the Cryptoassets Manual (the operational rule-set the agency itself uses) and the CG12100+ series for capital-gains computation. Every UK crypto-tax tool we review either auto-applies these rules (Recap, Koinly UK, Crypto Tax Calculator UK) or flags the manual computation requirement (CoinLedger UK, ZenLedger UK — both originally US-built tools, now adding UK rule support). The 2026 reporting deadline — Self Assessment SA106 + SA108 filed by 31 January 2027 for tax year 2025-26 — is the demand-driver behind crypto-tax × UK’s high-traffic spike in the December-January window. We surface the deadline in every UK crypto-tax review’s “Regulator coverage” section.