How HMRC Taxes Your Uniswap LP Position

You added liquidity to a Uniswap pool. Maybe ETH/USDC, maybe something more exotic. The tokens are earning fees, the position is ticking along, and at some point you'll need to file a tax return.

Here's the problem: most crypto tax tools treat LP positions like simple swaps. They see tokens leaving your wallet and call it a disposal. They see tokens coming back and call it an acquisition. The result? Phantom gains, inflated tax bills, and a report that won't survive HMRC scrutiny.

This guide walks through exactly how HMRC taxes Uniswap LP activity under current rules — what's taxable, what isn't, and where the common mistakes happen.

What actually happens when you add liquidity

When you add liquidity to a Uniswap V2 pool, you deposit two tokens (say, 1 ETH and 1,800 USDC) and receive LP tokens in return. On V3, you mint an NFT position instead, but the tax logic is the same.

From HMRC's perspective, you've disposed of your tokens in exchange for a new asset (the LP token or position). That's a taxable event — specifically, a Capital Gains Tax (CGT) event.

However, since you're acquiring a new asset (the LP position) at the same time, this is really a cost basis change — the value doesn't disappear, it moves into a new form. The cost basis of your LP position equals the combined market value of the tokens you put in.

Removing liquidity: where the real tax event hits

When you withdraw from the pool, you receive tokens back — but typically in different proportions than you deposited (thanks to impermanent loss and trading fees). This is where the CGT calculation matters most.

Your gain or loss is:

This gain feeds into your Section 104 pool — HMRC's method for averaging out the cost basis of identical assets. More on that below.

LP fee income: it's not capital gains

The fees you earn as a liquidity provider are a separate tax event. HMRC treats them as miscellaneous income, taxed at your income tax rate (20%, 40%, or 45% depending on your band) — not at CGT rates. The same rules apply to staking rewards and other DeFi income. Read our guide to reporting DeFi income →

On Uniswap V2, fees are automatically reinvested into the pool, so they're hard to isolate. On V3, you can collect them separately, which makes the tax treatment cleaner.

The three HMRC matching rules you need to know

When you dispose of tokens (including through LP withdrawal), HMRC doesn't let you just pick which acquisition to match against. There's a strict priority order:

1. Same-day rule — if you acquired and disposed of the same token on the same day, those match first. This prevents "bed and breakfasting" within a single day.
2. 30-day Bed & Breakfast rule — if you disposed of a token and reacquired the same token within 30 days, the disposal is matched against that reacquisition. This prevents selling at a loss and immediately buying back to crystallise the loss.
3. Section 104 pool — everything else goes into a shared pool of that token, with an average cost basis. Every acquisition adds to the pool; every disposal draws from it proportionally.

These rules apply to every token disposal — whether it's a simple sale on Coinbase or a complex multi-leg LP withdrawal on Uniswap V3.

2024/25: the split-year problem

The 2024/25 tax year has a unique complication. The Autumn Budget 2024 changed CGT rates on 30 October 2024:

This means every individual disposal in 2024/25 needs to be taxed at the rate that applied on the date it happened. You can't just apply one rate to the whole year.

If you removed LP liquidity in September 2024 and again in January 2025, those two disposals are taxed at different rates. This is reflected in SA108 Box 51 — an adjustment box that most tools don't even know exists.

What generic tax tools get wrong

We've seen the same mistakes across every major crypto tax tool when handling LP positions:

• Treating LP add as a simple transfer — this skips the disposal entirely, meaning the cost basis is never properly adjusted. When you later remove liquidity, the gain calculation is based on stale data.
• Missing the income/capital split — fee income gets lumped in with the capital gain on withdrawal. You end up with one number that's wrong for both CGT and income tax purposes.
• Ignoring multi-leg disposals — an LP position involves two tokens. Each leg needs to be priced separately at the time of the event. Tools that only track one side produce incorrect proceeds and cost basis figures.
• No split-year rate handling — they apply a single CGT rate to the entire 2024/25 tax year, which is simply wrong.

The cumulative effect? We've seen cases where these errors produce a CGT bill of £1,680 on activity that should actually result in just £124 of tax. That's £1,556 overpaid — on a single LP position.

CARF is coming — and HMRC will cross-check

From January 2026, around 50 UK crypto platforms are reporting user transaction data to HMRC under the Crypto-Asset Reporting Framework (CARF). The first data exchange happens in May 2027.

Your 2024/25 self-assessment return (due 31 January 2026) will be the first one HMRC can cross-reference against exchange-reported data. If your numbers don't match, expect questions.

Getting your DeFi classification right isn't just about paying the correct amount — it's about having an audit trail that holds up. "My tax tool said so" won't satisfy HMRC. You need to show your working.

What you should do

1. Don't assume your current tool handles DeFi correctly. Export your report and check a few LP transactions manually. If the tool shows a simple "swap" where you added liquidity, it's wrong.
2. Track both legs of every LP operation. Each token needs its own proceeds and cost basis calculation.
3. Separate fee income from capital gains. These are taxed at different rates and go on different parts of your return (SA108 for CGT, SA100 for income).
4. Check the date of every disposal in 2024/25. The rate that applies depends on whether it happened before or after 30 October. See the full 2024/25 guide →
5. Keep your working. HMRC can ask to see how you arrived at every number. A tool that shows you the S104 pool state, matching rule, and price source for each disposal is worth more than one that just gives you a final number.