HMRC's New Crypto Reporting Rules: What RCASP Means for Every UK Holder

Crypto trading in the UK has never really been anonymous, but for years HMRC's enforcement lagged behind the technology. From 1 January 2026, that gap closes. UK crypto platforms now have to collect detailed user and transaction data and report it straight to HMRC under the Reporting Cryptoasset Service Provider (RCASP) rules, the UK's rollout of the OECD's Crypto Asset Reporting Framework, known as CARF.

The first reports to HMRC are due by 31 May 2027, covering everything that happens during 2026. So if you hold or trade crypto in the UK, here is what changes, what gets sent to HMRC, and how to stay on the right side of it.

What RCASP actually is

RCASP is the UK's implementation of CARF, an international standard the OECD built specifically for crypto. Older frameworks like the Common Reporting Standard were designed for bank accounts, not digital assets. CARF fills that gap, and more than 40 jurisdictions have committed to it, including the entire EU through its DAC8 directive.

A Reporting Cryptoasset Service Provider is any platform that facilitates crypto trades, swaps, or transfers: exchanges, brokers, and custodial wallet providers with a UK connection. Once a platform is in scope, it stops being just a marketplace and becomes a data source for HMRC.

What gets reported to HMRC

The obligations are detailed and consistent across CARF countries, because they all trace back to the same OECD template. Reporting platforms have to collect your full identity, including name, date of birth, address, and your National Insurance number or tax reference. They then report the type and sterling value of every crypto transaction, along with the total units you traded or transferred during the year.

CARF is built around automatic exchange of information between countries. If you trade on a platform based in one CARF jurisdiction while being UK tax-resident, that data flows to HMRC without anyone having to request it. A transaction on an exchange in Ireland by a UK resident no longer slips through a jurisdictional gap. It gets matched.

No new taxes, just new visibility

It is worth being clear about what CARF does not do. It does not create new taxes. Capital Gains Tax and Income Tax have applied to crypto disposals and to staking and mining rewards for years, and the rules for what counts as a taxable disposal have not changed. What has changed is enforcement.

HMRC used to rely almost entirely on people self-reporting their crypto activity on their Self Assessment return. Now it receives the same transaction data directly from the platforms and compares the two, which is exactly how HMRC enforces crypto tax today. Any mismatch between what you declare and what an RCASP submits is an immediate audit flag. And with the Capital Gains Tax annual exempt amount now just £3,000, far more disposals are taxable than most casual holders assume.

How to get ahead of it

The practical response is the same whichever platforms you use. Keep your tax residency and identification details current with every exchange and wallet provider, because that information now flows straight to HMRC. Keep a clear record of every disposal, including crypto-to-crypto swaps and paying for goods with crypto, with the date, quantity, and sterling value at the time. Separate income from staking, mining, and airdrops out from ordinary trading, since it is taxed differently. And track the fees platforms and networks charge, because they affect your final gain or loss.

Because RCASP reporting pulls from every platform you touch, from centralised exchanges to DeFi protocols to cold storage wallets, consolidating that activity into a single record before you file is no longer optional if you want your numbers to match what HMRC already has.

Where this leaves you

CARF marks the end of crypto being a reporting blind spot, and that is not necessarily bad news. The people who feel the least stress from this shift are the ones who already keep clean, consolidated records rather than reconstructing a year of activity across a dozen platforms the night before the deadline. Piecing capital gains together by hand across multiple exchanges and wallets is exactly the kind of work that produces errors, and errors are precisely what an automated cross-checking system is built to catch.

Tools like Kryptos close that gap by connecting your wallets and exchanges directly and producing reports that already line up with what HMRC receives under RCASP. For the full picture of how the rules work, start with our UK crypto tax guide, then see how Kryptos handles UK crypto tax reporting.

About the author

Deepak Pareek

Head of Tax & Accounting - Kryptos