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Crypto Law/Level VII · Loopholes worth understanding/7.2 Residency and borders/Lesson 7

CARF: the end of quiet offshore accounts

How the OECD’s Crypto-Asset Reporting Framework sends crypto account data to the tax office of the country where the customer lives, and where the US stands.

Education, not legal, tax or investment advice. Crypto law differs between countries and states and changes often. Check the current rules where you live with a qualified lawyer or tax adviser before you act.

The lean path

The cheapest, lowest-tax, simplest and most private route the law allows, best first. Each step names the rule it rests on and the condition that keeps it lawful.

  1. Self-custody is lawful and a private wallet is not a CARF reporting entity, but a transfer from a platform to a private wallet is itself reported; gains made in self-custody remain taxable and must still be declared.
  2. Give platforms only what CARF requires, name, birth date, address, residence and tax number, and make it accurate; UK platforms send their first report, covering 2026, between 1 January and 31 May 2027.
  3. Report your own gains first: CARF data from 2026 starts moving between tax authorities in 2027, so correct filing now is cheaper than answering an inquiry built on platform data that contradicts your return.
  4. US persons sit outside CARF for now but face Form 1099-DA broker reporting plus FBAR and Form 8938 where thresholds apply; EU residents get the same data flow through DAC8 from 1 January 2026.

MaterialsHMRC guidance ‘Collecting cryptoasset user and transaction data’ and ‘Reporting cryptoasset user and transaction data’The International Joint Statement on the Crypto-Asset Reporting Framework (10 November 2023)The residence and tax number recorded on each of your exchange accounts

Wonder

  1. Does an exchange in another country tell my home tax office about my account?
  2. What exactly gets reported?
  3. Is the United States part of this?

Explore

  1. The Crypto-Asset Reporting Framework, or CARF, is an OECD standard for the automatic exchange of tax information about crypto. It builds on the Common Reporting Standard (CRS), the existing system under which participating countries exchange information on financial accounts held by foreign residents. The UK government says final agreement on CARF was reached in March 2023, after two years of negotiation. The idea is simple: a crypto platform collects each customer’s tax residence and reports their transactions to its own tax authority, which then passes the data to the tax authority of the country where the customer lives.
  2. On 10 November 2023, a group of jurisdictions including the UK published an International Joint Statement announcing their intention to implement CARF in time to begin exchanges by 2027, and to apply amendments to the CRS on the same timetable. The UK government noted that the OECD’s Global Forum on Transparency and Exchange of Information for Tax Purposes, then with 168 members, had a G20 mandate to oversee wider implementation. In the European Union, the same rules arrive through the directive known as DAC8, which applies from 1 January 2026 (lessons 1.3.3 and 8.2.2).
  3. Under the UK rules, platforms must collect, for each individual user, their name, date of birth, home address, country of residence and, for non-UK residents, their tax identification number and the country that issued it. For each transaction they record its value, the type of crypto-asset, the type of transaction and the number of units. HMRC’s manual lists the reportable categories: exchanges between crypto and ordinary currency, exchanges between crypto-assets, transfers, including transfers to wallet addresses not linked to a service provider, and certain retail payment transactions.
  4. The UK applies CARF from 1 January 2026. Platforms must send their first report between 1 January and 31 May 2027, covering calendar year 2026, and then report by 31 May every year. HMRC can charge a platform a penalty of up to £300 per user for failing to report, reporting late, or reporting inaccurately. The UK has also extended the rules so that platforms report UK-resident customers to HMRC, not only foreign ones. Self-custody wallets are not themselves reporting entities, but a transfer from a platform to a private wallet is one of the reportable transactions.
  5. The United States does not take part in the CRS; it relies on FATCA and, for crypto, on broker reporting on Form 1099-DA (lesson 2.3.5). A search of the Federal Register in October 2026 found no published US regulation implementing CARF, so the US side remains open. For a US citizen this changes little, because the US already taxes them wherever they live (lesson 7.2.1). For residents of CARF countries, an account on a foreign platform is no longer out of sight of their own tax office. FBAR and Form 8938 rules still apply separately to US persons (lesson 2.3.6).
  6. The title of this lesson is literal: an offshore crypto account that a residence country never hears about is becoming rare where CARF applies. Data that platforms collect in 2026 is due to start moving between tax authorities in 2027. A practical check: log in to each platform you use and note the country of residence and the tax number it holds for you, then compare these with where you actually file tax. A mismatch, in either direction, is what this system is designed to surface. This lesson explains the framework; it does not advise on how to report a particular account.

Key facts

  • The UK government says final agreement on the OECD’s Crypto-Asset Reporting Framework was reached in March 2023.
  • An International Joint Statement of 10 November 2023 announced the signatories’ intention to implement CARF in time to begin exchanges by 2027.
  • Under UK rules, platforms collect each individual user’s name, date of birth, home address, country of residence and, for non-UK residents, tax identification number.
  • Reportable CARF transactions include crypto-to-fiat exchanges, crypto-to-crypto exchanges and transfers, including transfers to wallets not linked to a service provider.
  • UK platforms submit their first CARF report between 1 January and 31 May 2027, covering 2026, and can face penalties of up to £300 per user.
  • As of October 2026, no US regulation implementing CARF had been published in the Federal Register.

Exercise nine, six, three, one

9CollectList up to 9 platforms, wallets or accounts that a real or imagined holder has used, with the country where each platform is based.
6ClusterSort them into 6 groups: domestic platforms, EU platforms, UK platforms, other CARF countries, non-CARF countries and self-custody wallets.
3DistillReduce the 6 to 3: which accounts would most likely be reported to the holder’s tax office, and from when?
1CrystallizeWrite 1 sentence explaining what changes for an offshore crypto account once its platform’s country applies CARF.

Fact check

Dates, figures and claims checked against the published sources listed below.

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