Crypto Lending and Borrowing Tax UK (Aave, Compound Explained)
If you have been earning yield on Aave or Compound, or borrowing stablecoins against your ETH, the crypto lending tax UK position is more complicated than most people assume. The usual belief is that lending crypto is a tax-free way to put idle tokens to work, and that borrowing against your holdings is simply a loan. Neither assumption is safe under current HMRC guidance.
This guide explains how the UK taxes lending and borrowing on decentralised finance (DeFi) protocols: when transferring tokens to a lending pool can be a disposal for Capital Gains Tax, why the interest you earn is usually taxable income, why borrowing itself is not taxed, and the one event that catches people out in a falling market: liquidation.
Key Takeaways
- Lending can be a disposal. If beneficial ownership of your tokens passes to the protocol, transferring them in is a CGT disposal at market value, even though you have not sold for cash.
- Interest and rewards are income. The return you earn on Aave or Compound is generally taxable as miscellaneous income at its £ value when received, which then becomes your CGT base cost.
- Borrowing is not a disposal. Taking a loan against your crypto is not taxed, because you keep ownership of the collateral.
- Liquidation is a disposal. If your collateral is sold off to repay a loan, that liquidation triggers CGT at market value, often at the worst possible time in a falling market.
- Gas fees are small disposals. Paying network fees in ETH or another token is itself a disposal of that token, with its own tiny gain or loss to track.
Crypto lending tax UK: the starting point
The UK has no special tax for DeFi. HMRC applies existing Capital Gains Tax and income tax rules to crypto activity, and sets out its view in the HMRC Cryptoassets Manual. There are two questions to answer for any lending or borrowing position:
- Was there a disposal? Disposals (selling, swapping, spending, or gifting to anyone other than a spouse) are within Capital Gains Tax.
- Was there income? Crypto received as a reward is taxed as income at its market value on receipt, and that value becomes the base cost for any future disposal.
For lending and borrowing, both can be live at once, which is what makes DeFi harder to report than a buy-and-hold portfolio.
Lending crypto: when it counts as a disposal
The intuitive view is that lending is not a sale, so nothing is taxed until you withdraw. HMRC’s DeFi lending and staking guidance is more nuanced, and the key test is beneficial ownership.
When you supply tokens, you usually receive a different token representing your deposit (an aToken on Aave, or a cToken on older Compound versions). If that means you give up beneficial ownership of the original asset, HMRC treats it as a disposal of the original tokens for CGT at their market value, and a second disposal can arise when you later redeem the position.
This matters because a gain can crystallise even though no fiat has changed hands: if your ETH has risen since you bought it, supplying it could realise that gain on paper. Whether ownership actually passes depends on the protocol and the terms, so each position has to be assessed on its facts.
Interest and rewards: taxed as income
Separately from any disposal, the return you earn for lending is generally taxable. HMRC’s position is that lending rewards typically have the nature of income rather than capital, and are taxed as miscellaneous income at their £ value when you become entitled to them. Two points follow:
- You need the sterling market value of each reward at the date of receipt, not when you withdraw it. With variable-rate protocols accruing value continuously, that can mean many small receipts to value.
- That receipt value becomes the base cost of the reward tokens, so when you later sell them your gain is measured against the value already taxed as income. You are not taxed twice.
For the overwhelming majority of retail lenders this miscellaneous income route applies. Only with unusually large, frequent and organised activity might HMRC argue it amounts to a trade.
Borrowing crypto: not a taxable event
Here is the good news. Borrowing against your crypto is not a disposal. When you lock ETH as collateral on Aave and draw stablecoins against it, you keep beneficial ownership of the ETH. You have not sold it, so there is no CGT on borrowing, and the borrowed funds are not income because a loan must be repaid.
This is why borrowing is often more tax-efficient than selling: if you need liquidity but do not want to trigger a gain on appreciated crypto, a loan lets you access cash value without a disposal. The catch is what happens next.
Liquidation: the disposal nobody plans for
Every collateralised loan has a liquidation threshold. If your collateral falls far enough relative to your debt, the protocol automatically sells part or all of it to repay the loan and protect the lenders. That forced sale is a disposal at market value, fully within Capital Gains Tax.
The timing is brutal, because liquidations happen in sharp market falls. That is precisely when your collateral is sold at a low price, yet you may still have a taxable gain if it is worth more than you originally paid. You can end up with a CGT bill on an asset you never chose to sell, and the tax does not disappear just because the market kept falling. Planning for liquidation, including the tax, is part of borrowing responsibly.
Gas fees and the many small disposals
Every on-chain action costs gas, usually paid in ETH. Spending crypto to pay a fee is itself a disposal of that crypto, with its own micro gain or loss measured against the ETH’s base cost.
Individually these are tiny. Across an active history of supplies, borrows, repayments and claims, they add up to hundreds of disposals that all need valuing and pooling. Allowable transaction costs can often be set against the related disposal, but only if they are tracked, which is the single biggest reason DIY DeFi spreadsheets fall apart.
Summary table: how each DeFi action is taxed
| Action | Tax treatment | Tax type |
|---|---|---|
| Supplying tokens to a lending pool | Possible disposal if beneficial ownership passes | CGT |
| Interest / lending rewards received | Taxable at £ value on receipt; becomes base cost | Income tax (miscellaneous) |
| Borrowing against collateral | Not a disposal; loan proceeds not income | No tax on the act |
| Collateral liquidated | Disposal at market value; gain or loss arises | CGT |
| Paying gas fees in crypto | Small disposal of the token spent | CGT |
| Withdrawing your own supplied tokens | Possible second disposal on unwinding | CGT |
Worked example: a liquidation in a falling market
Priya bought 4 ETH for £6,000 in total (a base cost of £1,500 each). Later, with ETH at £3,000, she supplies all 4 ETH (worth £12,000) as collateral on Aave and borrows £6,000 of stablecoins. Borrowing is not a disposal, so there is no tax at this point.
The market then drops sharply. ETH falls to £2,000 and her position is liquidated: the protocol sells her 4 ETH to repay the loan, a disposal at market value.
- Disposal proceeds: 4 ETH × £2,000 = £8,000
- Base cost: £6,000
- Capital gain: £2,000
Assume Priya has used none of her 2025/26 annual exempt amount of £3,000, so her £2,000 gain falls within the exemption and no CGT is due. But had she also realised other gains that year, the £2,000 would stack on top, and the part above £3,000 would be taxed at 18% within the basic-rate band or 24% above it, the rates for crypto disposals from 30 October 2024. The sting is that she has lost her ETH and still has a reportable disposal. Had her base cost been £3,000 in total, the same liquidation would produce a £5,000 gain, much of it taxable.
How a specialist handles it
When a client comes to us with a DeFi history, we work data first. We pull every wallet and protocol interaction on-chain, identify which supplies and withdrawals passed beneficial ownership, value every reward and gas fee in sterling on the right date, and run the disposals through Section 104 pooling in the correct same-day, then 30-day, then pool order. Only then do we know the true gain or income for each year.
Frequently Asked Questions
Is lending crypto on Aave or Compound taxable in the UK?
Potentially in two ways. Supplying tokens can be a CGT disposal if beneficial ownership passes to the protocol, and the rewards you earn are generally taxable as miscellaneous income at their £ value when received.
Do I pay tax just for borrowing against my crypto?
No. Borrowing is not a disposal because you keep ownership of the collateral, and the loan proceeds are not income because you must repay them.
What happens to my tax if my collateral is liquidated?
A liquidation is a disposal at market value. If the collateral is worth more than its base cost, a capital gain arises and can be taxable, even though the sale was forced.
How is the interest I earn from lending taxed?
Generally as miscellaneous income, valued in pounds at the date you become entitled to it. That value also becomes the base cost of the reward tokens, so you are not taxed twice when you later sell them.
Are gas fees relevant to my tax?
Yes. Paying gas in ETH or another token is a small disposal of that token, with its own gain or loss. Allowable transaction costs can often be offset against the related disposal if you keep records.
I also have US tax obligations. Does this change anything?
The US taxes digital assets under its own rules, and DeFi activity is reportable there too: see the IRS guidance on digital assets. As a UK and US specialist firm, we handle both sides together so positions are not double counted or missed.
Get your DeFi position reviewed before HMRC does
Lending and borrowing on protocols like Aave and Compound generate disposals and income that are easy to miss and hard to reconstruct after the fact. If tax is owed on past years, HMRC has a route to tell HMRC about unpaid tax on cryptoassets, and coming forward early keeps penalties low. Book a free, confidential review at certifiedcryptoaccountant.com, and see our crypto tax services for how we reconcile complex DeFi histories for UK and US clients.
Sources: HMRC Cryptoassets Manual, DeFi lending and staking (GOV.UK, https://www.gov.uk/hmrc-internal-manuals/cryptoassets-manual/crypto61000); Capital Gains Tax (GOV.UK, https://www.gov.uk/capital-gains-tax); Tell HMRC about unpaid tax on cryptoassets (GOV.UK, https://www.gov.uk/guidance/tell-hmrc-about-unpaid-tax-on-cryptoassets).