Cryptocurrency lending: how interest is taxed in Spain
Cryptocurrency lending is one of the most common ways to generate passive returns in the crypto ecosystem. You can lend your assets on DeFi protocols (Aave, Compound) or on CeFi platforms (Nexo, until its closure in certain markets). The interest received generates tax liability.
Types of lending and their tax treatment
1. Lending in DeFi protocols (Aave, Compound, Morpho)
What's happening?
- You deposit DAI (or other crypto) in Aave.
- You receive aDAI (a token that represents your deposit + accumulated interest).
- aDAI continually increases in value (accumulates interest).
- When you withdraw, you exchange DAI for DAI + interest.
Tax treatment:
- The initial deposit (DAI → aDAI): can be considered transmission. If the DAI had risen since your purchase, there is a capital gain.
- Accumulated interest in aDAI: return on capital at the time of withdrawal.
- Withdrawal (aDAI → DAI): possible capital gain or loss if the value of the aDAI differed from what was expected (cases of desynchronization).
2. Lending in CeFi (Nexo, Celsius until bankruptcy, etc.)
What's happening?
- You deposit crypto and receive periodic interest (daily, weekly or monthly) on the same or another crypto.
Tax treatment:
- The interest is yield of capital at the time of receipt.
- They are valued at the market price of the cryptocurrency received at that moment.
- The platform can act as a retainer (if it is Spanish or has obligations in Spain).
3. Guaranteed crypto loans (collateral loans)
Some platforms allow you to put BTC as collateral and receive USDC on loan:
- The collateral (BTC): it is not a sale, but there may be an obligation to declare a loss if the price drops and the collateral is liquidated.
- The loan itself: is not taxable (it is a debt, not income).
- Interest paid on the loan: they are not deductible in personal income tax (they could be deductible in a related economic activity).
- Collateral liquidation: if the price drops and the platform automatically sells your BTC, it is a forced sale → capital gain or loss.
When exactly is the taxable event generated?
| Event | Taxable event |
|---|---|
| Initial deposit | Possible transfer (if there is an exchange of assets) |
| Interest received periodically | Movable capital at the time of each payment |
| Total withdrawal + accrued interest | Movable capital for interest |
| Collateral Liquidation | Capital gain/loss |
Registration required
For each lending position you need:
- Date and value in euros of the initial deposit.
- Record of each interest payment (date + amount + price).
- Date and value upon withdrawal (to calculate capital gain/loss if applicable).
With DeFi platforms, obtaining this history requires querying the blockchain directly.
Bankruptcy of CeFi platforms (Celsius lesson, Voyager, etc.)
If the lending platform goes bankrupt:
- Actual loss of funds → property loss when the impossibility of recovery is confirmed.
- The interest collected before bankruptcy has already been taxed; they do not recover.
- You need to document: bankruptcy procedure, platform communications, recovery attempts.
Interest in stablecoins: seemingly simple, fiscally active
Lending USDC to Aave and receiving 5% annually in USDC may seem simple:
- 1,000 USDC deposited → 50 USDC interest per year.
- The 50 USDC are return on movable capital: approximately €50 (if 1 USDC ≈ €1).
But if the stablecoin has small price movements, the exact calculation requires the price at each collection moment.
Updated: April 2026 | Fiscal year: 2025