Topic: Finance · Crypto · Type: Evergreen · Reading time: ~8 min

The IRS estimates that roughly 75% of crypto traders never properly report their transactions. That number has aged badly. Starting with the 2025 tax year, every major crypto exchange is required to file Form 1099-DA directly with the IRS — meaning the agency now receives your trading data automatically, whether you report it or not. In the UK, the Cryptoasset Reporting Framework (CARF) came into force on 1 January 2026, giving HMRC automated data feeds from exchanges and triggering international information-sharing across dozens of tax jurisdictions.

The era of hoping nobody notices is over. What follows is a clear explanation of how crypto taxes actually work, where people consistently go wrong, and what staying compliant looks like in practice.

The foundational rule: crypto is property, not currency

Both the IRS and HMRC classify cryptocurrency as property for tax purposes. This sounds like a technicality but it has profound consequences. When you sell a stock at a profit, you owe capital gains tax. The same logic applies when you sell Bitcoin, swap ETH for USDC, use crypto to pay for anything, or receive staking rewards.

The misconception that catches most people out is this: you don't need to convert back to dollars or pounds to trigger a taxable event. Swapping one token for another is a disposal of the first token at its market value on the day of the swap. Buying a coffee with Bitcoin is a disposal. An airdrop you actively claimed is income. A hard fork allocation is income. The test is whether beneficial ownership of the asset has changed — not whether fiat money ever touched your account.

This is why the "I haven't cashed out" defence doesn't hold. It never did, legally. It's just that tax authorities didn't have the data to challenge it until now.

How the tax is actually calculated

The US framework

In the US, crypto gains are split into two categories based on holding period:

  • Short-term gains (held one year or less): taxed as ordinary income at rates between 10% and 37%, depending on your total taxable income.
  • Long-term gains (held more than one year): taxed at preferential rates of 0%, 15%, or 20%. For 2025, single filers with taxable income below $48,350 pay 0% on long-term gains.

The starting point for every calculation is your cost basis — what you paid for the asset, including fees. Your gain or loss is the difference between your sale proceeds and that adjusted cost basis. If your losses exceed your gains in a given year, you can use up to $3,000 of the excess to reduce ordinary taxable income, with the remainder carried forward indefinitely.

One complication that trips up active traders: cost basis method matters. The IRS now requires wallet-by-wallet accounting starting from 2025, meaning you can't average costs across all your wallets. FIFO (first in, first out) is the default, but HIFO (highest in, first out) or Specific ID can reduce your taxable gains legally — provided you identify the lot before the sale.

Worth knowing: Tax platforms like CoinLedger reported a 758% spike in IRS warning letters (Letters 6173 and 6174) sent to crypto holders over a 60-day window in mid-2025. Many recipients weren't tax evaders — they were ordinary investors who made cost-basis mistakes or missed small staking income from a few years earlier. Getting a letter doesn't mean prosecution; ignoring it usually does.

The UK framework

HMRC takes the same property-as-asset approach. Capital gains tax applies whenever you dispose of crypto — selling, swapping, spending, or gifting to anyone other than a spouse. For 2025/26, the annual CGT exempt amount is £3,000 (down sharply from £12,300 in 2022/23), meaning far more investors will find themselves in reportable territory.

Gains above that allowance are taxed at 18% for basic-rate taxpayers and 24% for higher and additional rate taxpayers. Staking rewards, mining income, and airdrops received in exchange for an action are treated as income, taxed at your marginal rate in the year received — and then subject to CGT again when you eventually dispose of the tokens (on any gain since receipt).

UK investors must use HMRC's share-pooling method for cost basis, which works differently from US accounting and produces different results for the same portfolio. If you've been using US-style FIFO on a UK return, your numbers are likely wrong.

What counts as a taxable event (and what doesn't)

This is where people most commonly underestimate their exposure. The following all trigger a tax event in most major jurisdictions:

  • Selling crypto for fiat currency
  • Swapping one crypto for another (e.g. ETH → BTC)
  • Using crypto to purchase goods or services
  • Receiving staking rewards, mining income, or yield
  • Receiving an airdrop (in most circumstances)
  • Receiving payment in crypto for work or services

The following generally do not trigger tax in themselves:

  • Buying crypto with fiat and holding it
  • Transferring between wallets you own
  • Gifting crypto to a spouse or civil partner (UK)
  • Gifting up to $19,000 per recipient in 2025 (US gift exclusion)
  • Donating crypto to a registered charity

The wallet-to-wallet transfer point is worth emphasising. Moving Bitcoin from Coinbase to a hardware wallet is not a disposal — but it does create a record-keeping requirement, because the cost basis travels with the asset. If your tracking software doesn't follow that movement correctly, it can misreport gains.

Understanding how crypto wallets actually work — including the difference between custodial and non-custodial setups matters more for tax compliance than most guides admit. Where you hold assets affects what data is available when you need to file.

The enforcement reality in 2025

The practical risk of non-compliance has increased sharply — and the mechanism is straightforward.

In the US, Form 1099-DA now flows directly from exchanges to the IRS. The agency's computer systems cross-reference what exchanges report with what you filed. Discrepancies generate automated notices. For cases where the IRS deployed Palantir — a data analytics platform it began using to identify underreporting — that process is increasingly accurate. There's an early Bitcoin investor who was sentenced to two years in prison and fined over $1 million for falsifying capital gains reports. That case set a tone.

In the UK, CARF requires all UK-registered cryptoasset service providers to collect and automatically report transaction data for all customers — including UK residents — as of January 2026. That data is shared internationally. If you hold crypto on a foreign exchange, HMRC may receive your information from that jurisdiction's equivalent framework.

Neither of these systems distinguishes between people who knew the rules and ignored them versus people who made honest mistakes. The systems flag discrepancies. You then have to explain them.

Practical compliance: what you actually need to do

The core requirement is records. Every transaction — the date, the asset, the quantity, the GBP or USD value at the time, the fee, and which wallet it was in — needs to be recorded. For anyone who has traded across multiple exchanges and wallets, this is non-trivial.

Crypto tax software (Koinly, CoinLedger, CoinTracking, and similar tools) connects to exchanges via API and reconstructs your transaction history automatically. It isn't perfect — DeFi positions and self-custody wallets often require manual entries — but it's substantially better than spreadsheets for volume traders. A Koinly report for HMRC starts at around £39; a comparable US report varies by transaction volume.

Three things to do now regardless of your jurisdiction:

  1. Export your transaction history from every exchange you've used, going back to when you started. Exchanges sometimes close, lose data, or change terms. The burden of proof is yours.

  2. Identify your cost basis method and apply it consistently. In the US, this means wallet-by-wallet from 2025 onwards. In the UK, share-pooling rules apply, which your software should handle automatically.

  3. Report losses as well as gains. Losses don't disappear if you ignore them — they can be carried forward and used to offset future gains. In the UK, you have four years from the end of the tax year to report a loss. In the US, losses can carry forward indefinitely. Unreported losses represent money left on the table.

If you've held positions that have lost significant value — particularly ETH, which dropped 46% in the 2024/25 UK tax year — tax-loss harvesting may be worth exploring with an advisor before you close those positions.

The DeFi grey zone

One area where both the US and UK are still working through the implications is decentralised finance. Providing liquidity to a pool, lending tokens, or staking on a protocol can — depending on jurisdiction and the specific mechanism — constitute a disposal at the point of entry, triggering tax before you've received any return.

The UK's Autumn Budget 2025 introduced a "no-gain/no-loss" treatment for certain DeFi lending and liquidity pool transactions, which would remove the immediate CGT charge on depositing assets. Draft legislation exists but the timeline for implementation remains unclear. Until it's law, the current rules technically apply — meaning some DeFi positions create tax events on entry.

In the US, DeFi platforms were tentatively excluded from the 2025 Form 1099-DA broker reporting rules (following a Congressional resolution signed in 2025), but taxable events still exist at the transaction level. Swap on Uniswap and you've disposed of one asset and acquired another — regardless of whether a 1099 follows.

For anyone active in DeFi, understanding what's actually being built in the space is necessary context for understanding what you're legally agreeing to when you interact with a protocol.

What this means for you

The tax treatment of crypto hasn't fundamentally changed — it's always been property, gains have always been taxable, and income from staking has always been reportable. What's changed is the enforcement infrastructure. The gap between what people owed and what they reported is now detectable at scale, automatically, without any investigator needing to build a case from scratch.

The single most useful thing you can do this week: log into every exchange account you've used, export your transaction history, and run it through a crypto tax tool to see what your position actually looks like. You may find you owe nothing — or that a year of losses you've never reported will offset gains you didn't realise you had.

Tax compliance is not complicated once you have accurate records. The complication is that most people don't have them.