The Accrual Principle in Cryptocurrencies: When Does the Tax Obligation Arise?

The accrual principle is one of the fundamental concepts of the Spanish IRPF: income and expenses are attributed to the tax period in which they occur, regardless of when they are received or paid. For cryptocurrencies, determining exactly when each event is accrued is crucial and not always obvious.

What Is the Accrual Principle in the IRPF?

Article 14 of the LIRPF establishes the principle of temporal attribution:

• Employment income → in the period of receipt.
• Income from movable and immovable capital → in the period in which it becomes due to the recipient.
• Capital gains and losses → in the period in which the capital alteration occurs.

For crypto, accrual occurs when there is a capital alteration (asset transfer) or when the income becomes due (for capital income).

Accrual of Capital Gains (Sales and Swaps)

Sale on an Exchange (Immediate Settlement)

• A sale on an exchange with instant settlement (spot trading) accrues the gain/loss at the moment the order is executed.
• If you sell BTC on December 31 of year N → the capital gain/loss is attributed to year N, even if the EUR does not reach your bank account until January 2 of year N+1.

Deferred or Installment Sale

If you make a crypto sale with deferred settlement (e.g., you agree to sell 1 BTC in 30 days at today's price in an OTC deal):

• Accrual may occur at the time of the agreement or at the time of settlement.
• The LGT generally states that for firm contracts (without a suspensive condition), accrual occurs on the date of the agreement.
• If there is a suspensive condition → accrual occurs when the condition is met.

Cryptocurrency Swap Transactions

When you exchange BTC for ETH (or any DeFi swap):

• The swap simultaneously accrues the capital gain/loss of BTC (value of BTC at the time) and the acquisition of ETH.
• Accrual date: the moment the on-chain transaction is confirmed.
• If the transaction is initiated on December 31 but not confirmed until January 1 → which year?
  • The relevant date is the blockchain confirmation.
  • If the confirmation block is at 11:00 PM on December 31 of year N → year N.
  • If the block is at 12:02 AM on January 1 → year N+1.

Accrual of Capital Income (Staking, Yield Farming)

Staking with Periodic Payments

• Staking rewards accrue at the moment they are credited to the taxpayer's wallet.
• If staking pays daily → daily accrual.
• If staking pays monthly → monthly accrual on the credit date.
• If staking has a minimum lock-up period before rewards can be claimed → accrual occurs at the moment the rewards become due (i.e., when you can claim them), not before.

Yield Farming with Rewards Accumulated in the Protocol

If the yield farming protocol accumulates your rewards in a contract (does not automatically send them, requiring you to "claim"):

• Accrual occurs when the rewards are available to claim (due) → even if you have not claimed them.
• Practical issue: Some investors do not claim rewards for months → rewards accrued in year N must be declared in year N even if you have not claimed them.
• This can create tax obligations without liquidity (you must pay taxes on rewards you have not yet "received" in EUR).

Accrual of Airdrops

• Airdrop accrual occurs at the moment the tokens arrive in your wallet (are available and due).
• If the airdrop has a subsequent vesting schedule (distribution schedule), each tranche of tokens accrues at the moment of distribution of that tranche.
• An airdrop announced in year N but distributed in year N+1 → accrues in year N+1.

Accrual of an Artist's NFT with Royalties

If you are the creator of an NFT and receive royalties on each secondary sale:

• Accrual: at the moment of each secondary sale when royalties are paid to you.
• Depending on the protocol, royalties may arrive automatically or require a claim.
• If a claim is required → same debate as in yield farming: due at the moment of the secondary sale even if you do not claim them.

Consequences of Incorrect Fiscal Year Attribution

If you declare income in year N+1 when it accrued in year N:

1. The AEAT may demand the tax for year N with surcharges and late payment interest.
2. The surcharge for late filing is 5% (up to 3 months), 10% (3-6 months), 15% (6-12 months), or 20% (more than 12 months) + late payment interest (4.0625% annually in 2025).
3. If the late filing is voluntary (before the AEAT requires it), you avoid the penalty (but not the surcharges).

The Special Case of High-Frequency Trading

Traders who perform thousands of daily transactions may find that:

• There are transactions at 11:59 PM on December 31 and others at 12:01 AM on January 1.
• Platforms use UTC timestamps → always convert to Spanish time (UTC+1 in winter, UTC+2 in summer) to determine the correct accrual year.
• The timestamp of the confirmation block is the relevant one.

Summary of Accrual by Type of Operation

Updated: April 2026 | Fiscal Year: 2025