01A nudge letter says HMRC holds third-party data suggesting you may have undeclared cryptoasset income or gains, and invites you to put it right.02It is a one-to-many campaign letter, not a formal enquiry — around 81,000 went out in the year to April 2026, and a new wave is running from July 2026 to March 2027.03The communication may request a response by a stated date. Outside a formal enquiry, HMRC one-to-many guidance distinguishes voluntary requests from statutory information powers. Use the deadline and instructions on the actual letter; HolderTax will not publish a universal response period until the current campaign document is archived.
What this letter is
HMRC's one-to-many programme sends the same letter to everyone a data-matching exercise has flagged — exchange records, and increasingly the reporting that feeds the CARF pipeline. Some arrive as post; the same campaign also runs through the HMRC app and by text. Receiving one is not a finding and not an accusation. It is a statement about data: your name appears in a set HMRC believes correlates with undeclared tax, and HMRC is offering the cheap exit before anyone opens a file.
The letter may invite you either to correct the position through an appropriate disclosure route or to explain why no tax is due. The precise response date and wording are campaign-document specific; follow the date printed on the letter and verify the operative route before replying.
"Voluntary" — read it twice
Two things are simultaneously true, and both matter. First: a nudge letter carries no formal information powers. It is a request. Second: it is a request from an organisation that has already matched data to your name and is telling you what happens if the request is ignored. Treating "voluntary" as "safe to bin" converts the cheapest stage of the sequence into a formal enquiry — with information notices, longer timelines, and a "prompted" label on any disclosure that follows, which raises the penalty band.
The nudge letter is the UK's quiet window with a date on it. Everything about your position is cheaper on the near side of that date.
The trap inside a fast reply
The most dangerous response to a nudge letter is a quick, confident one. "I checked, nothing to declare" — sent before actually reconstructing pooled positions — is a written statement HMRC can hold against the data it already has. The matching rules mean your intuition about your own gains is unreliable by design: swaps you did not think of as disposals, a 30-day repurchase that erased a loss you claimed, staking rewards that were income at receipt. Check the arithmetic first, on paper, before any sentence is sent.
What to do before the letter’s response date
- Date the letter and calendar day 60. Then set a working deadline two weeks earlier — reconstruction always takes longer than it looks.
- Rebuild the actual position before deciding anything. Every platform export, every wallet, sterling values, pools per token, income events. This is the same file that answers every later stage.
- If the reconstruction shows tax to pay — go to the disclosure page, not the reply. The route (and the penalty) depends on years and behaviour, and the response to the letter should follow that decision, not precede it. Read Disclosing prior years.
- If the reconstruction genuinely shows nothing due — reply, with the workings. A documented nil position, delivered on time, is how this correspondence ends. An undocumented assertion is how it continues.
- If the numbers are large, the years are many, or anything was deliberate — representation first. A tax adviser or tax-dispute specialist decides what is said, in which order, and keeps the first conversation privileged where possible.
If you ignored one already
The sequence continues without you: non-response feeds the case for opening a compliance check, and any disclosure made after further HMRC contact sits in the prompted band. The window narrows; it has not closed. The reconstruction is the same work today as it was on day one — it is only the discount that shrinks.
If you have received this letter, a response window is running. This page explains the letter; it does not respond to it, and reading it creates no professional relationship.