Received an HMRC Crypto Nudge Letter? Here’s What to Do

In the 2024-25 wave, HMRC sent roughly 65,000 nudge letters to crypto investors, more than double the number sent the year before, according to analysis by accountancy firm UHY Hacker Young reported in the Financial Times. If one has landed on your doormat, you are in large company, and what you do next matters.

The short version: do not panic, and do not ignore it. Here is what the letter means and how to respond sensibly.

What an HMRC crypto nudge letter actually means

A nudge letter is not an accusation of wrongdoing and it is not a formal tax enquiry. It is a prompt. HMRC holds data, typically supplied by cryptocurrency exchanges, suggesting you have bought, sold or held cryptoassets, and it is inviting you to check whether you have reported everything you should have.

That said, it is not a letter to file in a drawer. HMRC does not send these at random. It sends them to people who appear in the data it holds. If your tax affairs are not in order, the letter is your cue to fix that on the best available terms. Our guide on whether HMRC can track crypto explains just how much visibility HMRC now has.

Your options after receiving the letter

Broadly, there are three honest positions you can be in:

1. You have declared everything. Check your returns against your records, keep evidence of your workings, and respond if your letter asks you to. No further action should be needed.
2. You have something to declare, but it was a genuine oversight. Many investors did not realise that swapping one coin for another, or spending crypto, counts as a disposal for Capital Gains Tax. You can put this right through a disclosure.
3. You knowingly left crypto off your returns. The stakes are higher here, and penalties can be significant, but coming forward now is still far better than waiting for HMRC to open an enquiry.

In the second and third cases, HMRC’s cryptoasset disclosure facility is usually the route. We cover it in detail on our HMRC crypto voluntary disclosure page.

Deadlines and how to respond

Nudge letters usually ask you to review your position and act within a stated window, commonly around 30 to 60 days, though you should always check the exact wording and date on your own letter. Some versions ask for a signed certificate or declaration; think carefully and take advice before signing anything, because an inaccurate declaration can make matters worse.

If your records are scattered across exchanges and wallets and you cannot realistically complete the work in time, do not simply let the deadline pass. Engaging with HMRC, or registering an intention to disclose, shows good faith and protects your position.

How to check what you owe

To work out your position you will need your complete transaction history: every exchange account, wallet and platform, going back through the relevant years. Then apply the rules in HMRC’s Cryptoassets Manual:

• Crypto is a chargeable asset, so disposals can trigger Capital Gains Tax
• Disposals include sales, crypto-to-crypto swaps, spending and most gifts
• Gains are calculated using share pooling, with same-day and 30-day rules
• The annual exempt amount is £3,000, so gains above that are taxable
• Mining, staking and being paid in crypto can be subject to Income Tax instead

Tax software can help with simple histories. Anything involving DeFi, lost records, multiple wallets or several tax years usually benefits from a professional eye.

When to get help

Get help if you cannot reconstruct your records, if you are unsure whether past activity was taxable, if the letter asks you to sign a declaration, or if you already know something was missed. A specialist crypto tax accountant UK investors rely on can calculate the position accurately, and we handle the crypto data side: pulling together histories, rebuilding missing records and making sense of complex on-chain activity.

Frequently asked questions

Is an HMRC crypto nudge letter an investigation?

No. It is not a formal enquiry or an accusation. It means HMRC holds data suggesting you may have had cryptoasset activity and is inviting you to check your position. Ignoring it, however, can lead to a formal enquiry.

What happens if I ignore the letter?

Nothing good. HMRC already holds data on you, so silence tends to invite a formal compliance check. If tax is owed, penalties after HMRC opens an enquiry are higher than if you come forward first.

I checked and I owe nothing. Do I still need to respond?

Read your letter carefully, as wording varies between versions. Even where no reply is strictly required, it is often sensible to confirm your position and keep a record of your workings in case HMRC asks later.

How do I work out what I owe on my crypto?

Gather your full transaction history across all platforms, then apply HMRC’s share pooling rules, remembering that swaps and spending count as disposals. Software helps with simple cases; complex histories usually need professional review.

How long do I have to respond?

Typically around 30 to 60 days, but the exact deadline is on your letter. If you need more time to compile records, engage with the process rather than letting the date pass silently.

Speak to us

A nudge letter is unsettling, but it is also an opportunity to sort things out on favourable terms. We offer a free, no-obligation consultation: we will look at your letter, help you understand your position and map out the next step. Contact us today.

This article is general guidance, not personal tax or financial advice. Tax treatment depends on your individual circumstances and rules can change. Crypto Asset Consultants does not provide FCA-regulated financial advice.