Crypto Tax Accountant UK: Who Does What, and Who Can File

Short answer: A UK crypto tax accountant reconciles your exchange, wallet and DeFi history into HMRC section 104 pools, prices every disposal in sterling and produces the capital gains and income figures your Self Assessment needs. Filing the return and dealing with HMRC are separate jobs, and only an agent you have authorised can do those for you.

The title "crypto tax accountant" is not a protected credential in the UK, so it tells you almost nothing about what the person will actually do. Three different jobs hide behind it: reconciling the data, preparing the numbers, and filing with HMRC. This guide separates them, so you can work out which one you are buying before you pay for it.

What does a UK crypto tax accountant actually do?

A UK crypto tax accountant turns raw transaction data into HMRC-ready figures: every acquisition pooled by token type, every disposal priced in sterling on the day it happened, and every reward separated out as income rather than gain. The tax rules are the easy part. Getting a complete, correct transaction history is where the work sits.

HMRC treats a disposal as selling tokens, exchanging them for a different type of cryptoasset, using them to pay for goods or services, or giving them away to anyone other than a spouse, civil partner or charity (GOV.UK, check if you need to pay tax when you sell cryptoassets). That fourth category catches people out, and the second one catches almost everybody: a token to token swap is a disposal even though no pound ever moved.

Where the sterling figure on your return comes from

Every disposal needs a sterling proceeds figure and a sterling allowable cost, even when both legs of the trade were crypto. Somebody has to establish a price for each side at the moment of the transaction, across every venue you used. For a portfolio that touched several exchanges and a handful of chains, that is thousands of individual valuations, and it is the single largest part of the engagement.

Why pooling makes crypto harder than a share portfolio

Under TCGA 1992 section 104, tokens of the same type form a single pooled asset that rises and falls with each acquisition and disposal, and each token type needs its own pool with its own pooled allowable cost. HMRC also confirms that non-fungible tokens are separately identifiable, so they are not pooled and no matching rules apply to them (HMRC Cryptoassets Manual CRYPTO22200). A stockbroker gives you one statement. A crypto portfolio gives you twenty sources that do not agree with each other. Our UK crypto tax guide works through the pooling and matching rules in detail.

Who can file your Self Assessment and deal with HMRC for you?

You can always file your own Self Assessment return, or you can authorise an agent such as an accountant or tax adviser to manage your tax affairs. Once you have authorised someone, HMRC sends correspondence to them rather than to you, with the exception of tax bills and refunds (GOV.UK, appoint someone to deal with HMRC on your behalf). Producing the figures and submitting the return are separate acts, and one provider does not have to do both.

What authorising an agent actually changes

Authorisation moves the correspondence, not the liability. The return remains yours, and the figures on it remain your responsibility, which is why the quality of the reconciliation underneath matters more than whose name appears in the agent box.

Can you file the return yourself from somebody else's report?

Yes. A great many UK investors have a specialist produce the gain, loss and income figures and then enter them on their own return or hand them to the accountant who already does their tax. There is nothing irregular about splitting the work that way, and for a complex portfolio it is often the cheaper route.

Why UK crypto engagements are reconciliation before they are tax

Most of a UK crypto engagement is data work, not tax analysis. The tax treatment of a disposal is settled law; what is unsettled is what actually happened across your wallets, which exchange records survived, and where the acquisitions went. Everything downstream depends on getting that right.

The data problem behind most UK returns

Exchanges close, APIs change, CSV exports drop internal transfers, and self-custody wallets produce no statement at all. A history assembled from partial sources will still produce a clean-looking number, which is the dangerous part: the report looks internally consistent while being wrong.

What one missing acquisition does to a pool

Because section 104 pools every unit of a token together, a single missing purchase reduces the pooled allowable cost and inflates the gain on every later disposal of that token, not just the one nearest to it. That is why "close enough" data is not close enough. We cover the repair in how to fix missing cost basis.

What should a UK crypto tax engagement deliver?

A UK engagement should hand you the figures for the capital gains pages, a separate income schedule, and the working that supports both, in a form you or your accountant can file from directly. If you cannot see how a number was reached, you cannot defend it.

The figures the capital gains pages need

Disposals are reported on the Capital Gains summary pages of the Self Assessment return (GOV.UK, Self Assessment capital gains summary SA108).

For the 2026 to 2027 tax year the Capital Gains Tax annual exempt amount is £3,000, and gains are taxed at 18% within the basic rate band and 24% above it from 6 April 2026 (GOV.UK, Capital Gains Tax rates).

Income that never reaches the capital gains pages

Staking rewards are dealt with as income under HMRC's guidance rather than as capital gains at the point of receipt (HMRC Cryptoassets Manual CRYPTO21200), and they then carry a base cost into the pool for the eventual disposal. An engagement that reports only gains has left half the return undone.

Which UK situations need a specialist rather than a general accountant?

A general accountant is enough when the history is a handful of exchange trades with clean records. A specialist earns their fee when the data is broken, the protocols are unusual, or earlier years were never reported.

DeFi lending and liquidity positions

HMRC has a dedicated section of its manual for decentralised finance lending and staking (HMRC Cryptoassets Manual CRYPTO61000), and the analysis turns on what actually happened on chain, including whether beneficial ownership of the tokens passed. Reading that off a spreadsheet row labelled "transfer" is not possible; it has to be read off the chain.

Staking rewards and airdrops

Reward streams arrive continuously, often in tokens with thin pricing, and each receipt needs a date, a sterling value and a place in the pool. Volume alone puts this beyond a manual process for most portfolios.

Years you have not reported yet

HMRC operates a route for telling it about unpaid tax on cryptoassets (GOV.UK, tell HMRC about unpaid tax on cryptoassets), and a disclosure needs the earlier years reconstructed properly before anything is submitted. See how to voluntarily disclose unpaid crypto tax to HMRC, and what HMRC can already see.

What does a crypto tax accountant cost in the UK?

Price follows the work, and the work follows the state of your data rather than the size of your portfolio. A large but tidy portfolio on two exchanges is cheaper to handle than a small one spread over nine chains with two dead exchanges in the history.

What moves the price of a UK engagement

• The number of venues and chains, and whether records survive for each
• The number of taxable events, not the value of the holdings
• DeFi protocols that need on-chain decoding rather than a CSV import
• How many earlier years have to be rebuilt to establish today's pools
• Whether an exchange has closed and the records have to be reconstructed

CountDeFi quotes fixed fees rather than hourly rates; the current bands are on the pricing page.

How do you check a UK crypto tax accountant is genuine?

Ask how they handle the parts that are hard, not the parts that are easy. Anyone can import a Koinly file. The answer to "what do you do when an acquisition is missing" separates a specialist from a reseller in about thirty seconds.

Questions worth asking before you pay

• What happens when a wallet's history is incomplete, and who does that work?
• How do you price a token that had no reliable market on the day it moved?
• Will you reconcile my closing balances against the chain and the exchange?
• Which of the four jobs in the table above are you doing, and which am I?
• Will I get the working, or only the totals?

What a CSV-import shop sounds like

If the process described is "send us your exports and we will run the software", you are buying a software licence with an invoice attached. Software is a useful tool and a poor answer on its own, as we set out in the pros and cons of crypto tax software.

Where does CountDeFi fit for UK investors?

CountDeFi is a firm of crypto tax accountants that reconciles the history and produces the HMRC-ready capital gains and income figures. We do not file Self Assessment returns and we do not act as your HMRC agent, so the report is written to be filed by you or by the accountant who already acts for you. Chris Herbst is a Chartered Business Accountant in Practice (CBAP) with the Chartered Institute for Business Accountants and a General Tax Practitioner (GTP) with the South African Institute of Taxation.

We have worked with more than 1,000 clients globally since 2017, and the cases that come to us are usually the ones software could not close: dead exchanges, unlabelled DeFi, missing years. See the UK crypto tax accounting service or the wider crypto tax accounting service, or book a free call with one of CountDeFi's crypto tax specialists. If you are still deciding which kind of provider you need, what a crypto tax advisor is and when you need one sets out the four types.