How is crypto reported to tax authorities, and what records should you keep?

US: the forms

US individuals report crypto in three places.¹

• The digital asset question. Every year, the main Form 1040 asks whether you received, sold, swapped or otherwise disposed of a digital asset.¹
• Form 8949 and Schedule D. Sales and swaps are listed on Form 8949, Sales and Other Dispositions of Capital Assets, and totalled on Schedule D.^2,7 From the 2025 tax year, digital assets have their own boxes: G, H and I for short-term, and J, K and L for long-term.⁵
• Schedule 1. Income from forks, staking, mining and similar activities goes on Schedule 1 of Form 1040.¹

You must report all taxable digital asset transactions, whatever the amount, even if no one sends you a tax form about them.^2,5

US: Form 1099-DA

Brokers, such as crypto exchanges that hold your coins, now report your sales to the IRS on a new form, Form 1099-DA.¹

The rules cover brokers that take possession of the crypto being sold. As of October 2026, they do not include "decentralized or non-custodial" brokers that never hold it.¹ If every Form 1099-DA you receive shows the basis was reported to the IRS, and nothing needs correcting, you may not need to file Form 8949 for those sales.⁵

UK: the return

UK individuals report gains on a Self Assessment tax return, or through HMRC's real-time Capital Gains Tax service.³ From the 2024 to 2025 tax year, the Self Assessment return has its own cryptoasset section, filled in in pounds sterling.³

For income such as staking rewards, GOV.UK says to tell HMRC if your total miscellaneous income is between £1,000 and £2,500, and to register for Self Assessment if it is over £2,500.⁸

Records to keep

HMRC warns that exchanges may only keep records for a short time, or may close before you file. So it is up to you to keep your own records of every transaction.⁹ The IRS says the law requires records that are enough to support what you put on your return.²

Between them, the two authorities ask for:^1,9

• the type of crypto, and the date (and, for the IRS, the time) of each transaction;^1,9
• whether you bought, sold or received it, and the number of units;^9,1
• the value in dollars or pounds at the time of the transaction;^1,9
• your cost basis for anything you sold;¹
• the running total of units you hold, and for the UK, your pooled costs before and after each disposal;^9,3
• bank statements and wallet addresses;⁹
• how you valued each transaction, if there was no direct price.¹⁰

GOV.UK adds that exchange reports can help, but they are not tax calculations and they will not track your pooled costs.³

Tax authorities share data

OECD CARF. The Crypto-Asset Reporting Framework (CARF) is an international standard from the OECD. Crypto firms collect data on their users and report it each year, and tax authorities then send it to the authorities where the users live.¹¹ As of 14 September 2026, the OECD listed 46 jurisdictions due to start these exchanges by 2027, 27 by 2028 and 4 by 2029. The United States is in the 2029 group.¹²

UK. From 1 January 2026, UK crypto firms must carry out checks on their customers under the CARF.⁴ Their first reports, covering 2026, are due between 1 January and 31 May 2027. A firm that breaks the rules can be fined up to £300 per user.⁶

EU. The EU's version is DAC8, a directive adopted in October 2023 and based on the CARF.^13,14 EU countries had to apply it from 1 January 2026, and must exchange the data within nine months after the end of each year.¹⁴ The European Commission says the exchanges for the first year, 2026, will take place by 30 September 2027.¹³