HMRC sent 81,000 cryptoasset letters, emails and texts in 2025/26, three times the 2023/24 count (FinanceFeeds). The recipients land on your desk with three years of exchange exports, a closed exchange and a wallet nobody can explain. The tax is quick. Rebuilding the history is not.
The window is closing. UK platforms file their first CARF reports on calendar 2026 by 31 May 2027, and the 2025/26 return is due 31 January 2027. Send us one client and we hand back the working papers for every year named. First one free.
The disclosure service asks for gains and income per year, with the computations uploaded. That is the pack, with the trail behind every figure.
Every disposal in sterling, same-day, 30-day and Section 104 matching, net gain, annual exempt amount and crypto income for each year the letter names.
One row per year: what was on the return, what should have been, and the taxable gain and income to disclose. 2024/25 is split at 30 October 2024 for the rate change.
The per-year gains and income the cryptoasset disclosure service asks for, and the same set for the Worldwide Disclosure Facility where there is an offshore element. You add the tax, interest and penalty.
The CC/FS7a ranges laid against the client’s years, with the facts that decide behaviour left for you to judge. We do not pick the behaviour.
Where each exchange and wallet history starts and ends, what reconciles, and what cannot be traced, listed row by row rather than assumed.
Prepared for your firm, for your review. You sign and submit. We supply the working papers.
Prepared for: Your firm · Client: Sample client · Years 2023/24 to 2025/26 · Section 104 · GBP
Scenario: the client received a nudge letter and reported no cryptoassets on any return. Six sources, 13,686 source rows. Figures are from our UK sample workpaper; the client is synthetic.
| Tax year | On return | Disposals | Proceeds | Net gain | Exempt amount | Taxable gain | Crypto income |
|---|---|---|---|---|---|---|---|
| 2023/24 | Nothing | 1,793 | £545,050.34 | £12,028.27 | (£6,000.00) | £6,028.27 | £5,857.48 |
| 2024/25 | Nothing | 1,088 | £293,950.97 | £8,543.75 | (£3,000.00) | £5,543.75 | £6,751.69 |
| 2025/26 | Nothing | 1,079 | £286,329.79 | £15,333.37 | (£3,000.00) | £12,333.37 | £5,407.52 |
Income is staking rewards (miscellaneous income). Tax, interest and penalty are computed by you from these figures and the client’s other income.
| Tax year | Gains | Losses | Net gain |
|---|---|---|---|
| 2023/24 | £55,122.75 | (£43,094.48) | £12,028.27 |
| 2024/25 | £33,114.05 | (£24,570.30) | £8,543.75 |
| 2025/26 | £36,820.88 | (£21,487.51) | £15,333.37 |
No losses carried forward in any year. The 2025/26 SA108 boxes, the Section 104 pools and one disposal traced leg by leg are in the full 2025/26 workpaper (PDF).
| Behaviour | Unprompted | Prompted |
|---|---|---|
| Reasonable care | No penalty | No penalty |
| Careless | 0% to 30% | 15% to 30% |
| Deliberate | 20% to 70% | 35% to 70% |
| Deliberate and concealed | 30% to 100% | 50% to 100% |
Percentages of potential lost revenue, from HMRC factsheet CC/FS7a. Behaviour sets the ceiling: 30% for careless, 70% for deliberate, 100% for deliberate and concealed. Timing and the quality of disclosure set where the penalty lands inside the range. A disclosure is unprompted only if made before the client has reason to believe HMRC has found or is about to find the inaccuracy. Offshore matters can go higher (CC/FS17). The pack sets out the facts; the behaviour call is yours.
| Source | Type | History | Continuity |
|---|---|---|---|
| Coinbase | API + CSV | 6 Apr 2023 to 4 Apr 2026 | Continuous, 180 duplicates removed |
| FTX | Historical export | 6 Apr 2023 to 28 Feb 2024 | Stops mid-history |
| Ethereum Wallet 1 | On-chain | 6 Apr 2023 to 4 Apr 2026 | Continuous |
| Ethereum Wallet 2 | On-chain | 6 Apr 2023 to 4 Apr 2026 | Continuous |
| Solana Wallet | On-chain | 6 Apr 2023 to 3 Apr 2026 | Continuous |
| Bitcoin Wallet | On-chain | 10 Apr 2023 to 4 Apr 2026 | 40 receipts with no acquisition record |
Source of funds unevidenced. They starve the BTC pool, so 15 disposals in 2025/26 carry nil cost and £3,416.20 of gain. Reported at nil cost, not at an assumed cost. Client to explain.
Excluded from every figure and listed for client evidence, not estimated.
FTX ends 28 Feb 2024. Anything moved out before then is traced to the wallet that received it.
The client connects exchanges read-only or sends their exports, or you forward them. Tell us which years the letter names.
Figures for every year named, the gaps listed, the penalty note and the source-of-funds trace. Self-serve is ready as soon as the data is in. Done-for-you usually takes about 5 business days.
Every figure traces to a source row. Query anything, we answer. You decide the route, the behaviour and the submission.
First client free. One nudge-letter client, the full pack, no card. See whether it saves you the hours before you pay for anything.
Self-serve pack. The client or you import the data; the pack builds itself. Support by email if a figure needs explaining.
Done for you. We reconcile the history, chase the gaps with the client’s data and hand you the finished pack to review.
Larger or messier cases are quoted at our Concierge bands (£499, £999, £1,999) before any work starts. Clients typically pay £150 to £400 for a crypto return, so the pack leaves room for your fee.
Gains, income, the undisclosed-years table, the penalty ranges and the trace, for each tax year you ask for.
Live and closed exchanges, self-custody wallets, bridges, wraps and staking. Gaps are listed, never filled with guesses.
Careless or deliberate, DDS or WDF, whether to sign a certificate of tax position: your judgement, not ours.
We do not file, disclose or correspond with HMRC. You do.
These depend on the client’s other income and your view of behaviour. We give the gains and income they are computed from.
Moonscape is software and a data service, not a firm of tax advisers. Responsibility for the return or disclosure stays with you and your client. See HMRC’s cryptoasset disclosure guidance.
They give you a software seat and a calculation. The pack is built for the letter: every year named, laid out for the disclosure service, with the penalty ranges and the source-of-funds trace alongside. You can keep your existing tool for returns.
No. It sets out the CC/FS7a ranges against each year and the facts in the data. Behaviour and the quality of disclosure are for you to judge.
HMRC calls a disclosure unprompted only if it comes before the taxpayer has reason to believe HMRC has found or is about to find the inaccuracy. Most advisers treat a letter in hand as removing that. It is your call on the facts.
You do. We supply the working papers; you review them, form a view, and submit under your name.
Missing cost is reported as nil cost and listed row by row, so you can see the effect and ask the client. Nothing is assumed.
The client can connect read-only themselves, so you never forward credentials. Data is used only to build the pack. Ask us for our data processing terms before you share anything.
Any year there is data for. HMRC looks back 4 years with reasonable care, 6 if careless and 20 if deliberate.
Tell us the years on the letter and where the client traded. We reply within one business day with what we need, and the first pack is free.