HMRC sent more than 81,000 warning letters to UK crypto holders over unpaid tax

HM Revenue and Customs (@HMRCgovuk) sent more than 81,000 warning letters, emails and text messages to crypto investors during the 2025-26 financial year, according to data obtained by accountancy firm UHY Hacker Young through a Freedom of Information request, as reported by the BBC. The figure is nearly three times the 27,714 notices issued in 2023-24, marking a sharp escalation in the UK tax authority's pursuit of unpaid gains on digital assets.

A Crackdown Fuelled by a Years-Long Bull Market

HMRC believes a significant volume of capital gains tax remains unpaid from the prolonged crypto bull run that stretched from December 2022 to October 2025, during which the price of $BTC rose from around £14,000 to roughly £90,000. The so-called "nudge letters" are designed to prompt recipients to review and correct their filings voluntarily before a formal investigation is opened.

Neela Chauhan, partner at UHY Hacker Young, said the surge in notices reflects a broader assumption among tax authorities that crypto investment is an area prone to non-compliance. "A lot of the traders are young, have had little previous exposure to HMRC and often work under the assumption that HMRC has limited visibility over their activities," she noted. Tax experts also warn that many investors do not realise that swapping one token for another is itself a taxable event under UK capital gains rules.

New Reporting Rules Tighten the Net Further

The letter campaign is running alongside a significant expansion of HMRC's data-gathering powers. Rules requiring UK-based crypto platforms to collect detailed customer and transaction data took effect on 1 January 2026, with the first reports due to be submitted to HMRC by May 2027. Offshore platforms operating across dozens of jurisdictions that have signed up to the OECD's Crypto-Asset Reporting Framework (CARF) will follow from 2027, broadening the reach of automatic information exchange considerably.

The Treasury estimates the combined regime will raise up to £315 million in unpaid tax by April 2030. Non-compliance carries a penalty of up to £300 per unreported customer for platforms that fail to submit accurate data.

With an estimated seven million UK adults now holding crypto assets, according to the Financial Conduct Authority, the pool of potential taxpayers under scrutiny is large. HMRC's message to holders is straightforward: the window in which crypto activity could go undetected is closing fast.

Sources:
81,000 warning letters sent to crypto holders in HMRC tax crackdown (Yahoo Finance)
UK confirms new digital assets tax reporting rules for January 2026 (CoinGeek)
Nudge letters sent to crypto traders more than double (UHY Hacker Young)