If you have received an HMRC nudge letter about your cryptoassets, it is important that you don’t ignore it and take some action to ensure that you do not open yourself up to a later HMRC formal investigation.
An HMRC nudge letter is not the same as a formal tax investigation, and it does not automatically mean HMRC believes you have deliberately done anything wrong. A nudge letter means HMRC holds information suggesting you have been active in crypto and wants you to check (nudge you) into reviewing whether your tax affairs are fully up to date. However, it is important to take some action as if you do ignore it, even if you are compliant and up to date, HMRC may open up a formal investigation if they have not had any response.
Handled properly, a nudge letter from HMRC can be an opportunity to review your position calmly, correct anything that needs correcting and deal with matters before they escalate.
What is an HMRC nudge letter?
An HMRC nudge letter is a letter sent to taxpayers where HMRC believes there may be a tax issue that needs to be reviewed by the taxpayer and encourage them to comply with any tax requirements. These letters are sometimes referred to as “One to Many” letters because they are sent to groups of taxpayers who may have a similar issue.
In the case of cryptoassets, an HMRC crypto nudge letter usually means HMRC has received information suggesting that a person has bought or sold cryptoassets. HMRC is then asking the taxpayer to check whether any income or gains should have been reported.
Receiving a crypto nudge letter does not always mean that tax is due. Some people who receive these letters will have no taxable gains and will have already checked their position, others may have capital losses to claim, others may not have tax reporting and some people will owe tax on prior years cryptoasset trading and need to get compliant. In all cases the historic activity needs to have been reviewed before the position is clear.
What it does mean is that HMRC’s visibility over crypto activity continues to increase. HMRC already receives information from third parties, including some crypto platforms, and the Crypto Asset Reporting Framework (CARF) will significantly increase the amount of user and transaction data reported to tax authorities. From 2026, reporting cryptoasset service providers (RCASPs) will be required to collect information on relevant users and transactions, with the first reports to HMRC covering the 2026 calendar year to be submitted by 31 May 2027.
In simple terms, crypto hasn’t been outside of HMRC’s view with 65,000 nudge letters sent in 2025 alone and the information they are going to get is going to be exponentially much greater. If you receive an HMRC nudge letter, it should be taken seriously and is a chance to review your tax liabilities and make sure that you are compliant or that you get compliant with the tax regulations.
Check that the HMRC nudge letter is genuine
Before you respond to anything, make sure the communication is genuine. Scammers regularly use HMRC’s name to obtain personal details, payment information or login credentials, and crypto tax is an obvious area for fraudsters to exploit.
If you receive an unexpected email, text message or online message claiming to be from HMRC about crypto, be cautious. Do not click links, do not open attachments and do not provide personal information unless you are sure the communication is genuine. Suspicious HMRC emails can be forwarded to [email protected].
If you have received a posted HMRC nudge letter and are unsure whether it is genuine, check the contact details independently rather than relying only on the details in the letter. You can also ask a professional adviser to review it for you.
Do not ignore a nudge letter from HMRC
Once you are satisfied the letter is genuine, the most important thing is not to ignore it. HMRC may not have opened a formal enquiry at this stage, but the nudge letter is still a clear signal that HMRC expects you to check your position and respond appropriately.
The tone of HMRC’s crypto letters has become firmer over time from educational to prompt to do something. If you do nothing, the issue does not simply disappear. HMRC may decide to take further action, which could include opening a formal enquiry.
That is usually a far more stressful and expensive position to be in and can result in far more serious consequences. You would always want taxpayers to be compliant from the beginning or to voluntarily come forward when they realise the rules but there has been a misunderstanding about what is taxable i.e. swapping a cryptoasset to another one is a taxable event, the fact that a taxpayer hasn’t cashed anything out does not mean there are not taxable events to calculate.
It is always better to deal with an HMRC nudge letter rather than wait for consequence and to use it for its purpose as an opportunity to review the taxable reporting requirements and make sure that you are correctly reporting to HMRC. If HMRC considered there to be deliberate non disclosure they can escalate to criminal prosecution route.
Work out whether there is anything to report
This is where many people get caught out, because the UK tax treatment of crypto does not always match how people think about their activity.
One of the most common misconceptions is that there is nothing to report unless money has been withdrawn to a bank account. Unfortunately, that is not how the rules work. For Capital Gains Tax purposes, the key point is usually whether there has been a disposal.
A disposal can happen when you sell crypto for pounds or another fiat currency. It can also happen for a number of events that are not limited to; when you swap one token for another, take a loan out collateralised on your crypto, going in and out of DeFi contracts and spending crypto on goods or services often using exchange card services, or gifting crypto to someone other than your spouse or civil partner. The tax point is the disposal itself, not the point at which funds arrive in your bank account.
This means someone can have a reportable gain even if they have never “cashed out” in the ordinary sense. For example, swapping Bitcoin for Ethereum can be a disposal for tax purposes, even though no pounds were received.
There is also income to consider from rewards or staking, employment income where a cryptoasset (the employer’s token for example) is provided as a benefit or received in salary.
Gather your full crypto transaction history
To work out the correct position, you will need a complete record of your crypto activity. This should cover your full available history across every exchange, wallet and platform you have used, not just the tax year mentioned in the HMRC nudge letter.
This is important because crypto tax calculations often depend on earlier purchases, transfers and disposals. If historic acquisition costs are missing, the calculation may be wrong. If transfers between your own wallets are not identified properly, they may be mistaken for disposals or new acquisitions when they come into a wallet. If DeFi, staking, lending, bridging or NFT activity is involved, the position can become more complicated again.
This part of the process is often the hardest. Many people have used several exchanges over the years, some of which may have changed their export formats or closed entirely. Others have moved assets through self-custody wallets, decentralised exchanges and protocols that do not provide neat tax reports as there is no format standard for reporting.
It is better to take time to reconstruct the position properly and identify any gaps clearly.
Consider a voluntary disclosure if tax is due
If your review shows that tax has been underpaid, the usual next step is to make a voluntary disclosure to HMRC.
Coming forward voluntarily is putting you in a better position than waiting for HMRC to chase or to come to you with a formal investigation. It allows you to explain what happened, correct the tax position and deal with the matter in a more controlled way. It can also help reduce the consequences including mitigating penalties, for giving, telling and helping and particularly in cases where taxpayers have taken reasonable care, cooperated with HMRC and made a full disclosure.
It is critical that any disclosure is complete to the best of knowledge of the taxpayer and supported by correct calculations. Wilfully leaving information out and trying to hide any data could involve the most serious of sanctions including criminal prosecution.
Get advice before replying to HMRC
You do not have to deal with an HMRC nudge letter on your own, and it is sensible to get advice before sending a response to HMRC.
Understanding what information HMRC may have is a useful starting point and advisers can help to explain why you have been provided with the letter. What you say matters and so does the quality of the calculation behind it. A short reply saying that everything is fine is not sufficient if the underlying position has not been checked properly and could also be considered as deliberately being non compliant if you haven’t checked your records. Carrying out a review of the transactions will be required if it hasn’t already been done to check for errors or failure to notify HMRC of tax due.
Crypto tax can be straightforward in simple cases, but it can quickly become complex where there are multiple wallets, token swaps, DeFi transactions, staking rewards, NFTs, missing data or historic activity.
Specialist advice can help you understand whether there is anything to report, prepare the calculation properly and respond to HMRC in a way that is clear, accurate and proportionate.
How Knightbridge Tax can help with an HMRC nudge letter
At Knightbridge Tax, we regularly help clients deal with HMRC nudge letters, crypto tax disclosures and historic crypto tax issues.
We can review the letter, reconstruct your crypto transaction history across exchanges and wallets, calculate your true gains and losses, identify missing data or problem areas, and manage the response or disclosure to HMRC from start to finish.
If you have received an HMRC nudge letter about crypto, the most important thing is not to panic and not to ignore it. Get in touch and we will help you deal with it calmly, properly and with a clear plan.
If you have not received a nudge letter but think you should have disclosed then it is always better to come forward to HMRC, before they come to you. Please contact us for a discussion about your situation and how we can help. We also work with other firms where we can refer for legal assistance where required.
Disclaimer: This article is for general information only and does not constitute tax advice. UK tax treatment depends on your individual circumstances and may change over time. You should seek professional advice before taking any action. Knightbridge Tax Ltd accepts no liability for any reliance placed on this content.