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Explore common crypto tax risks and the practical steps available to correct past returns.
Published on 13 October, 2026
Crypto tax reporting can be complex. Multiple exchanges, high transaction volumes, staking rewards, token swaps and ever evolving HMRC guidance can make it difficult to confirm whether previous returns are accurate.
At Markel Tax, we can help clients confirm their crypto tax affairs are correct and address concerns about past returns. Issues often emerge only when specialist software analyses historic transactions.
The Hidden Risks in Cryptocurrency Tax Reporting
Investors often prepare returns using limited information from individual exchanges or wallet providers. Later analysis may reveal a more complex tax position.
Common issues include:
- Incorrect capital gains
- Undisclosed staking or reward income
- Missing transaction history
- Incomplete records across exchanges
- Historic filings requiring review
The key challenge is deciding what to do next and which correction route to use.
Why Specialist Advice Matters
Crypto tax involves more than calculating gains and entering them on a return.
We assess both capital gains and income. For example, staking rewards may need separate treatment from disposal gains, affecting the overall tax liability.
We help clients:
- Review transaction data and supporting data
- Consider the tax treatment of crypto income and gains
- Check past returns against available records
- Identify risk areas
- Prepare a strategy to resolve the issues identified
HMRC’s Growing Focus on Cryptocurrency Investors
Recent reports and HMRC data show growing scrutiny of crypto tax compliance. In 2025–26, HMRC sent 81,172 warning letters, emails and texts to investors suspected of underpaying tax—almost three times the 27,714 sent in 2023–24.
HMRC’s first statistics on taxable cryptoasset gains add context. In 2024–25, 17,600 people reported disposals subject to Capital Gains Tax, with proceeds of £13.8 billion and gains of £1.38 billion. The average gain was £78,000; 240 people reported gains above £1 million, together accounting for £717 million.
These figures cover only declared gains, but HMRC’s visibility is set to increase. A Capital Gains Tax disposal can arise when crypto is sold for cash or exchanged for another cryptoasset. From 2027, the Cryptoasset Reporting Framework (CARF) is expected to give HMRC customer data from service providers in participating jurisdictions, helping it compare platform records with tax returns and identify undeclared gains or income.
The message is clear: assuming HMRC has limited visibility of crypto transactions is increasingly risky. Anyone who has used multiple exchanges, received staking rewards, swapped tokens or has incomplete historic records should review their position before HMRC makes contact. Undeclared gains or income may result in tax, interest and penalties, making accurate records and early professional advice essential.
Source: 81,000 warning letters sent to crypto holders in HMRC tax crackdown - BBC News
Source: 240 crypto millionaires revealed in new government data - GOV.UK
Act Before HMRC Makes Contact
Taxpayers should address concerns before HMRC makes contact.
With HMRC increasing prompts and gaining wider access to international platform data, delays can make it harder to reconstruct transactions and select the appropriate correction route.
Gathering the facts and seeking advice promptly helps clients choose the best course of action.
A structured review can determine:
- Whether previous returns need correction
- The supporting evidence available
- The relevant tax years involved
- How to present any technical issues to HMRC
A Practical Approach to Complex Cases
We do more than identify problems. We help clients understand their tax position and agree a clear, practical way forward.
For crypto activity spanning several years, we can review historic returns, analyse transactions and provide advice tailored to the client’s circumstances. We recognise the stress of uncertain past tax affairs and focus on clear, commercially sensible guidance.
How Markel Tax Can Help
Whether preparing a current return, reviewing past filings or assessing the tax impact of crypto investments, early specialist advice can make a real difference.
Our experienced team helps clients navigate complex tax issues with confidence. Acting now can clarify your position and prevent unwelcome surprises.
Need cryptocurrency tax advice?
If you are concerned about historic crypto transactions, staking income, capital gains or past returns, Markel Tax can explain your options and help you move forward with confidence.
