HMRC is contacting increasing numbers of people about their crypto tax affairs.
Figures obtained from HMRC through Freedom of Information requests reportedly show that HMRC sent 81,172 crypto-related warning communications during 2025-26. That follows 64,982 in 2024-25 and 27,713 in 2023-24.
At the same time, relatively few people appear to have used HMRC’s dedicated Cryptoasset Disclosure Service to correct historic crypto tax. As at 4 December 2025, only 405 disclosures had reportedly been made through the service.
Those figures measure different things and should not be directly compared. The first includes HMRC communications such as letters, emails and text messages, while taxpayers can correct historic tax through routes other than the Cryptoasset Disclosure Service.
Even with those limitations, 405 disclosures through a service created specifically for historic crypto tax errors is a surprisingly small number.
HMRC is contacting more people about crypto tax
HMRC does not hide the fact that it contacts people about their cryptoasset activity.
Its own GOV.UK guidance states that if you have traded in cryptoassets, HMRC may contact you by letter, email or text message. HMRC says these communications direct people to check whether they have declared their crypto activity correctly and whether they need to report crypto income or gains.
That distinction matters.
Receiving an HMRC crypto tax letter does not mean HMRC has established that you owe tax. A nudge letter may prompt you to check your position because HMRC holds information suggesting that you have undertaken cryptoasset activity.
You then need to establish whether that activity created a UK tax liability and whether you reported it correctly.
Why have there been only 405 crypto tax disclosures?
HMRC introduced its dedicated Cryptoasset Disclosure Service in November 2023.
The service allows individuals to make a voluntary disclosure where they identify unpaid tax on cryptoassets, including exchange tokens such as Bitcoin, NFTs and utility tokens.
According to figures obtained from HMRC through a Freedom of Information request, only 405 disclosures had been made through the service by 4 December 2025:
| Tax year | Disclosures | Amount offered |
|---|---|---|
| 2023-24 | 17 | £136,403.47 |
| 2024-25 | 243 | £3,998,066.11 |
| 2025-26 to 4 December 2025 | 145 | £1,922,847.67 |
| Total | 405 | £6,057,317.25 |
HMRC reportedly cautioned that these amounts had not all been checked and agreed, so they should not be treated as tax finally accepted by HMRC.
The 405 figure also does not represent every historic crypto tax correction. Taxpayers may have corrected returns through Self Assessment or made disclosures through other HMRC routes.
Nevertheless, I find the number interesting.
Cryptoassets have been widely held for years, while understanding of their UK tax treatment has developed considerably over that period. In my experience, historic crypto tax errors are not unusual.
Why historic crypto tax can become a problem
Some investors may have assumed tax only became relevant when they converted cryptocurrency into pounds. However, exchanging one cryptoasset for another can also create a disposal for Capital Gains Tax purposes.
Others may have received staking rewards, mining income or other cryptoasset income without considering the Income Tax position.
Then there are people who simply never calculated their historic position.
I encountered an extreme example during an introductory call with a prospective client.
The individual was a young cryptoasset user undertaking around 100,000 transactions each year, regularly changing wallets and carrying out activity alongside a wider group of individuals.
No proper historic transaction records had been maintained, despite the value of the cryptoassets having increased substantially. More importantly, there was no willingness to establish and correct any historic tax position. The intention was simply to start calculating tax correctly going forward.
I declined to act.
The example stayed with me because starting to report correctly today does not remove a potential historic tax liability. Where years of high-volume crypto activity have already taken place, the first question should be whether earlier income and gains were reported correctly and whether sufficient records still exist to establish the position.
What does HMRC’s crypto compliance guidance say?
One of the more interesting aspects of HMRC’s approach is that much of its technical crypto compliance guidance is publicly available.
HMRC’s Cryptoassets Manual contains a dedicated compliance section for its officers. The guidance covers areas including cryptoasset risks, identifying cryptoasset activity, cryptoassets in investigations, information powers and case referrals.
HMRC’s published guidance also explains the information powers available when it needs information from cryptoasset exchanges.
This provides useful context for the increase in HMRC crypto tax communications.
HMRC does not necessarily need to know the exact amount of tax due before it contacts someone. Information indicating cryptoasset activity may be enough to prompt further questions or encourage the taxpayer to review their position.
What information may HMRC already have?
HMRC has obtained information about cryptoasset users for several years, and its access to data continues to develop.
An exchange may hold information about purchases, sales, withdrawals, deposits and customer identity. HMRC can also compare information from different sources when assessing tax risk.
However, information showing crypto activity does not automatically produce the correct tax calculation.
For example:
| Information available | What still needs to be established |
|---|---|
| Cryptoassets sold | Acquisition cost and resulting gain or loss |
| Large transaction volume | Whether there was any taxable gain |
| Cryptoassets received | Whether the receipt was income, an acquisition or a transfer |
| Exchange withdrawals | Whether assets were sold or simply moved elsewhere |
| Activity on one exchange | Whether other exchanges and wallets affect the calculation |
This is why reviewing the complete transaction history matters.
HMRC may have enough information to identify a possible risk without having enough information to calculate the correct liability.
I have looked at this wider issue separately in my article on HMRC Connect and AI, which explains how HMRC increasingly uses data to identify possible tax risks.
CARF will give HMRC more information about crypto activity
HMRC’s access to cryptoasset information is expanding further through the Cryptoasset Reporting Framework, or CARF.
From 1 January 2026, UK reporting cryptoasset service providers must collect information about users and their transactions. This includes transaction value, the type of cryptoasset, the type of transaction and the number of units.
HMRC’s guidance to cryptoasset users is particularly clear about why it wants identifying information:
“The information you give is used to link your cryptoasset activity to your tax record.”
The first CARF reports covering 2026 are due between 1 January and 31 May 2027.
HMRC may also receive information about UK residents who use cryptoasset service providers in other countries participating in CARF.
I have covered CARF and what it means for UK crypto investors separately, but the important point here is simple: HMRC’s visibility of cryptoasset activity is increasing.
What if you find an historic crypto tax error?
If you have traded or received cryptoassets for several years but have never reviewed the tax position, it may be worth doing so before HMRC contacts you.
That does not mean assuming that you owe tax. The first step is establishing what actually happened.
That may involve identifying:
- which tax years need reviewing
- which exchanges, wallets and platforms were used
- whether the transaction history is complete
- whether disposals created Capital Gains Tax consequences
- whether cryptoasset income was received
- whether previous tax returns included the relevant income and gains; and
- whether any historic error needs correcting
If unpaid tax is identified, the correct route for putting matters right will depend on the circumstances.
HMRC’s Cryptoasset Disclosure Service requires considerably more than a final tax figure. HMRC asks for information including the number of transactions, undeclared proceeds or income, acquisition costs, gains or profits, exchanges used, tax and interest calculations, and details of any commercial cryptoasset calculator used.
A historic crypto tax disclosure therefore needs to start with a supportable calculation.
What if your crypto records are incomplete?
Historic records are often where the real difficulty begins.
Exchange accounts may have closed. Platforms may limit historic downloads. Wallets may have changed. Transaction histories may sit across several exchanges and blockchains.
Where the records are incomplete, the position may need to be reconstructed before anyone can determine whether a disclosure is required.
Sat Tax provides a crypto reconciliation support where cryptoasset records need more detailed review or correction before they can support a tax calculation.
This is also why keeping copies of exchange exports, wallet addresses and transaction records remains important even after a tax return has been filed.
How can you correct historic crypto tax?
There are broadly two different situations.
If you identify an historic error before HMRC contacts you, you may need to make a voluntary disclosure. Sat Tax’s Earlier Year Crypto Tax Disclosure Service deals with previously undeclared or incorrectly reported cryptoasset income and gains where historic years need correcting.
If HMRC has already contacted you about your cryptoasset activity, the position is different. The first step should be understanding what HMRC is asking, reviewing the underlying records and establishing whether the tax position originally reported was correct. Sat Tax provides HMRC Crypto Tax Enquiry Support for this type of compliance work.
Not every HMRC crypto letter means tax is due, and not every historic crypto investor needs to make a disclosure.
The important point is to establish the position rather than assume it.
What do the 81,172 HMRC contacts and 405 disclosures tell us?
The headline figure of 81,172 HMRC crypto communications shows how much attention HMRC now gives crypto tax compliance.
The 405 disclosures made through HMRC’s dedicated Cryptoasset Disclosure Service tell a different story. They do not tell us how many people have undeclared crypto tax, and they do not capture every way taxpayers can correct historic errors. But they show relatively limited use of a disclosure service that HMRC created specifically for unpaid crypto tax.
From my own experience, historic crypto tax issues do exist. They can range from relatively straightforward missed disposals or income to years of high-volume activity with incomplete records.
At the same time, receiving an HMRC letter does not prove that anything is wrong. HMRC may have information that prompts a question without having the complete transaction history needed to establish the correct tax position.
The sensible approach is to establish the facts.
If you discover an historic error before HMRC contacts you, there may be an opportunity to correct the position voluntarily. If HMRC has already contacted you, review the records and understand the tax position before responding.
With HMRC already sending increasing numbers of crypto-related communications and CARF adding another source of transaction data, historic crypto activity is becoming increasingly difficult to leave unresolved.
If you are unsure whether historic cryptoasset activity has been reported correctly, get in contact or speak to a tax adviser who understands cryptoassets and the UK tax rules.
This article is for general information only and is not personal tax advice. Tax treatment depends on the facts and the law in force. See the website disclaimer.
