Cryptocurrency investors across the United Kingdom are facing a stringent new deadline to declare their profits to HM Revenue & Customs (HMRC). A major international information-sharing agreement, which took effect on January 1, 2026, is designed to significantly reduce the ability to hide gains from assets like Bitcoin.
New Reporting Rules Target Crypto Assets
The cornerstone of this crackdown is the Cryptoasset Reporting Framework (CARF). Under this new regime, investment and trading platforms are now legally required to collect and report detailed transaction information directly to tax authorities. This data will be automatically shared across international borders, creating a global net for HMRC and other tax bodies.
This move directly addresses what HMRC has identified as "high levels of non-compliance" among crypto investors. For the 2024-25 tax year, sellers of digital currencies who have realised profits will find it far more challenging to avoid declaring any tax owed.
Impact on Self-Assessment Tax Returns
The practical effect for UK taxpayers is a notable change to the self-assessment process. The familiar tax return form now includes a dedicated new section where individuals must input specific details of their profits and losses from cryptoassets.
Dawn Register, a tax dispute resolution partner at accountants BDO, explained the implications. "These new rules will give HMRC access to a much richer dataset on cryptoasset investors and their transactions," she stated. "Information will be shared automatically across international borders, allowing HMRC to better target those UK tax residents it suspects of failing to correctly declare their gains."
Deadline and Wider Regulatory Context
The absolute deadline for filing these returns is January 31. This regulatory shift coincides with ongoing consultations by the Financial Conduct Authority (FCA) on tougher rules for the crypto industry, which may include measures to prevent insider trading.
The Treasury has clarified that the CARF framework is intended to close a loophole. It prevents taxpayers from avoiding reporting under the existing Common Reporting Standard by simply moving funds into cryptoassets. The government is also encouraging voluntary disclosure from individuals who may have unpaid tax from earlier years.
Ms Register issued a clear warning to all investors: Anyone who made gains from cryptocurrencies in the 2024-25 financial year may now be obligated to file a tax return by the end of January, using the new dedicated section.
This regulatory tightening comes after a volatile year for the market. Bitcoin, often viewed as the industry benchmark, saw its value swing dramatically in 2025, starting the year at approximately $93,500 (£69,500), peaking near $124,500, before falling back below $90,000 by year's end.
