- Hong Kong’s legislature has passed a law requiring crypto firms to collect customer identity and transaction records from 2027.
- The territory begins passing that information to overseas tax authorities in 2028.
- The UK is signed up to the same international standard, which is how a Hong Kong law ends up concerning a UK resident.
Hong Kong has spent several years positioning itself as a place to run a crypto business. Its legislature has now passed a law requiring those businesses to collect customer identities and trading records, and to hand them to tax authorities overseas.
If you hold coins on an exchange based outside the UK, this is the machinery that eventually puts your name and your annual trading totals in front of HMRC without you sending anything. It doesn’t create a new tax and it doesn’t change what you owe. It changes who already knows.
What the law actually requires
The framework behind it is the Crypto-Asset Reporting Framework, drawn up by the OECD, the club of mostly wealthy countries that writes international tax standards. Its purpose is narrow. Banks have reported account holders across borders for about a decade under a similar system; crypto platforms sat outside it, and this closes that gap.
In practice an exchange collects two things. First, who you are: name, address, date of birth, where you are tax resident and your taxpayer number. Second, what you did with the account over the year.
That second part is less dramatic than people assume. The reporting is annual and aggregated, gross amounts by category, rather than a trade-by-trade log of your account. The categories do the work. Purchases with ordinary money, disposals back into ordinary money, crypto-to-crypto swaps, and transfers out to a wallet the exchange doesn’t control all get counted separately.
The swap line and the external transfer line are the ones that catch people out. Swapping one for another is a disposal for UK capital gains purposes even though no pounds moved, and plenty of holders have never treated it as one. Our crypto tax guide covers how that works in practice.
Why a Hong Kong law reaches a UK holder
A reporting standard only functions if enough countries adopt it, which is the point of doing it through the OECD. The UK is among the jurisdictions that have committed, and HMRC has told providers operating here to start collecting user data from January 2026, with the first reports following in 2027.
Once two jurisdictions are both inside the system, the data flows along tax residence rather than geography. A Hong Kong exchange with a customer who ticks “United Kingdom” on the residency form reports that customer to the Hong Kong authority, which passes the file to HMRC. The reverse happens too.
Which is the part worth sitting up for. Using an offshore platform has, for a lot of people, been an informal privacy decision rather than an evasion strategy. From 2028, on this timetable, it stops being either.
Reporting, not a new tax
Nothing here changes a UK tax bill. Capital gains rules on crypto are what they already were, the annual exempt amount is what it already was, and a loss-making year stays a loss-making year.
What changes is the asymmetry. A self-assessment return that doesn’t mention a Hong Kong exchange account currently sits unchallenged unless something else prompts a look. Against a file that lists disposals and swaps on that account, it doesn’t.
HMRC has run nudge letter campaigns on crypto before, built from data it obtained from exchanges on a one-off basis. This replaces that with an annual feed.
The year in the middle
Collection beginning in 2027 and sharing beginning in 2028 is not a drafting quirk. Firms need a reporting year to collect, and the authority needs the following year to validate the files and send them on. The same shape appears in the UK timetable.
It also means the first data that leaves Hong Kong covers the 2027 calendar year, not anything before it. That is the practical boundary, and it is the detail most likely to get flattened in coverage of this.
One limitation on everything above. We could not locate the text of the bill or a statement from the Hong Kong government, so the dates and scope here rest on CoinDesk’s report of the vote.
What to watch
Whether Hong Kong publishes the list of jurisdictions it will exchange with, and whether the UK is on it from the start. Commitment to the framework and a signed bilateral arrangement are different things, and the second one is what makes the first operational.
Beyond that, watch what exchanges ask you for. The visible version of this law is a residency and tax number request appearing in account settings, probably well before 2027. Platforms that run the collection badly will be the ones scrambling in the final months.