Undeclared Crypto Gains? Avoid HMRC Penalties

If you have made gains from cryptocurrency whether through trading, selling, staking or exchanging digital assets and have not yet declared those earnings to HMRC, time is running out to put your affairs in order on the most favourable terms.

HMRC Targeting Crypto Non-Compliance

HMRC has long made clear that cryptoassets are subject to Capital Gains Tax and, in some cases, Income Tax. Until recently, however, enforcement was largely reactive. That is changing rapidly.

The Global Information Sharing: DAC8 and CARF

The enforcement picture is set to become dramatically clearer from 2027 onwards, driven by two major international frameworks.

DAC8 - the EU’s eighth Directive on Administrative Cooperation took effect on 1 January 2026 across all 27 EU member states. It requires crypto asset service providers (exchanges, brokers and wallet platforms) to collect detailed user and transaction data and report it to national tax authorities, who will then share that information automatically across EU borders. First exchanges of data are expected by September 2027, covering the 2026 reporting year.

Crypto Asset Reporting Framework (CARF) - In parallel, the UK is implementing the OECD’s CARF which is now live in over 50 countries. UK-based platforms are required to collect user data from 1 January 2026 and submit their first reports to HMRC between January and May 2027 for the 2026 calendar year. The data reported includes names, addresses, National Insurance numbers and full transaction histories.

Why Acting Now Makes a Significant Difference

The key distinction and the one that will directly affect how much you pay is whether your disclosure is unprompted or prompted.

Coming forward before HMRC contacts you i.e. sends you some form of 'nudge letter' to review your crypto assets typically results in substantially lower penalties in some cases, none at all for a careless error.

If HMRC contact you first, penalties rise sharply and the terms become far less favourable.

What Disclosure Facility is Available?

For undeclared crypto gains, HMRC operates a dedicated Cryptoasset Disclosure Service (CDS), accessible online via a Government Gateway account. You will need to provide personal details, the relevant tax years, and accurate figures for any undeclared income or gains. Where records are incomplete, reasonable estimates may be used, but accuracy is paramount inaccurate disclosures can attract further scrutiny.

What This Means for You

If you have undeclared crypto gains or income from prior years, the practical steps are:

• Gather transaction records across all exchanges, wallets and platforms used.

• Identify each taxable event - disposals, exchanges, staking rewards, airdrops and employment-linked tokens all carry potential liabilities.

• Calculate gains and income accurately for each relevant tax year.

• Make a voluntary, unprompted disclosure via HMRC’s Cryptoasset Disclosure Service before receiving any communication from HMRC.

• Agree payment of any outstanding tax, interest and applicable penalties. A Time to Pay arrangement can be negotiated if needed.

TAP can help you navigate this process from calculating your liability and preparing the disclosure, to liaising with HMRC on your behalf and ensuring your ongoing compliance as the new reporting rules take effect.

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