Swapping to stablecoins: capital gain or neutrality?
The DGT’s position: an exchange between distinct assets
The DGT treats the exchange between distinct crypto-assets as a barter. This conclusion rests on the administrative doctrine on crypto barters —among others, V0999-18— and on Article 37.1.h of the Personal Income Tax Act. It bears noting that the DGT has not confined itself to that starting doctrine, which concerned volatile cryptocurrencies: in ruling 0018-23 (2023) —whose main subject matter was in fact evidentiary— it simply subsumes the stablecoin within the category of virtual currency and applies to it the same barter treatment, without granting it any special treatment. It defines the stablecoin as a cryptocurrency whose value is pegged to one or more fiat currencies or other assets. Recall, however, that this ruling is not binding —because the taxpayer had already filed their self-assessment when they consulted (Article 89.2 of the General Tax Act (LGT))—, so that it operates as a confirmatory administrative criterion and not as binding doctrine.
In practical terms, this means that someone who converts 1 BTC —acquired at €10,000— into USDC when bitcoin trades at €80,000 realises a capital gain of €70,000, even though they have not left the crypto environment or withdrawn funds to a bank account. The transaction is taxed in the tax year of the swap. Symmetrically, if the swap occurs at a loss, the capital loss is computable and may be set against the savings base, provided it is duly evidenced (Article 33.5.a LIRPF).
The counter-arguments: economic function and international comparison
The DGT’s position is technically correct within the literal wording of the rule, but economically arguable. The argument against it is twofold.
First, the function as a substitute for money: a stablecoin referenced to a legal-tender currency has, by design, a stable value. Its acquisition produces no return different from that of holding the reference currency, so that swapping bitcoin for a stablecoin is economically equivalent to swapping it for dollars. Second, the international comparison: in other jurisdictions, treatments closer to neutrality have been debated for certain currency-referenced tokens. Spain, as things stand, has not introduced an exception of that kind.
Our reasoned opinion
Until there is a legislative amendment or a different judicial criterion, the prudent position remains to treat the move from bitcoin or ether to a stablecoin issued by a third party as a barter with tax effect. What is arguable, in our view, is the legislative policy or the economic rationality of the result, rather than the direction of the administrative criterion in force. Anyone who wishes to depart from it in a self-assessment —a criterion repeatedly held by the DGT in its binding rulings on the barter of crypto-assets (among others, V0999-18 and V1948-21) and expressly applied to stablecoins in ruling 0018-23 (2023)— must be aware that they do so against a consolidated administrative criterion and assuming the corresponding risk.
- V0999-18 — the exchange between distinct cryptocurrencies is classified as a barter and gives rise to a capital gain or loss; as the stablecoin is another crypto-asset, the same criterion reaches the swap of bitcoin or ether for USDC or USDT.
- 0018-23 — in a ruling whose main subject matter was in fact evidentiary, the DGT subsumes the stablecoin —which it defines as a cryptocurrency whose value is pegged to one or more fiat currencies or other assets— within the category of virtual currency and applies to it the same barter treatment (Articles 33.1 and 37.1.h LIRPF): the exchange gives rise to a capital gain or loss, without granting it any special treatment. It is a non-binding ruling —because the taxpayer had already filed their self-assessment when they consulted (Article 89.2 LGT)—, so that it operates as a confirmatory criterion, not as binding doctrine.
Applicable legislation: Articles 33.1 and 37.1.h) LIRPF.