Form 721 (modelo 721) is the Spanish information return on crypto-assets held abroad: you report, you do not pay anything. It binds only those holding cryptocurrency custodied by non-Spanish entities above €50,000 on 31 December. Answer three questions and we will tell you.
Form 721 reports what a third party custodies. If you hold the private keys, there is no third party: there is nothing to report on this form, whatever it is worth. A Ledger with a million in bitcoin stays out. What decides is not how much you hold, but who keeps it.
Not the high of the year, nor the average, nor what it is worth when you file. It is what it was worth on that day. If on 12 November you held €90,000 and on 31 December €40,000, you are not over the threshold.
Filing form 721 generates no tax bill. It is an information return and that is all. What has consequences is not filing it when you should. That is why it is one of the few formalities where there is no rational reason to take the risk.
Whether or not you file form 721 does not change what you pay when you sell. They are two different things: form 721 reports what you hold abroad; Spanish income tax (IRPF) taxes what you gain when you sell or swap. You may have to file both, one, or neither. For the second there is the crypto tax calculator for Spain.
Individuals and companies tax resident in Spain that on 31 December hold cryptocurrency custodied by entities not resident in Spain —exchanges and custodians based outside— with a combined value above €50,000. The holder counts, and so does anyone who is a beneficiary of the account or authorised on it. The threshold is per person and every foreign platform adds up: two accounts of €30,000 on two foreign exchanges bind you just as much as one of €60,000.
For each entity that custodies: its name, address and country. And for each cryptocurrency you hold with it: the units on 31 December and their value in euros that day. The rules say which rate: the 31 December price quoted by the main trading platforms or by the price-tracking sites; failing that, a reasonable estimate of market value. Keep a record of where each figure came from: if the Agencia Tributaria, the Spanish tax authority, asks, that is the first thing it will want.
From 1 January to 31 March of the year after the one being reported, online, through the electronic office of the Agencia Tributaria. The first campaign was the 2024 one, for balances on 31 December 2023; it is a new form, and that is why plenty of people who have held cryptocurrency abroad for years do not know it exists.
Not every year. Once filed, it only comes round again if the combined value on 31 December has risen by more than €20,000 over the last return, and also when you stop holding a balance on a platform you reported: that closure is reported too. If your balance falls or barely moves, there is nothing to file.
Form 721 was born in 2023, after the Court of Justice of the European Union struck down in 2022 the penalty regime of form 720, so it is penalised under the general regime of the General Tax Act (articles 198 and 199): for not filing, €20 per item or set of items, with a minimum of €300 and a maximum of €20,000; if you file late without the tax authority having asked you for it, half of that. Filing it incomplete or with incorrect data has its own penalty. It is money paid for not filling in a form that costs nothing.
If the platform is Spanish —Bit2Me, say, or any of those the ESMA register places in Spain— it stays out of form 721 as well: it already reports to the Agencia Tributaria through forms 172 and 173. The list of authorised providers tells you, for each one, which authority supervises it and where it is based.
For the rest of the tax picture —FIFO, swaps, savings bands, staking— and for where to start, the guides hub. And if you are looking for somewhere to trade with an authorised platform, the list of providers with a MiCA licence — which also tells you which ones are Spanish and which are not, and that is exactly what decides whether this form applies to you.
Sources: the form 721 page in the Agencia Tributaria's electronic office and its frequently asked questions; Order HFP/886/2023, which approves the form, and articles 198 and 199 of the General Tax Act for the penalties. All of them are published in Spanish only. Text reviewed on 3 September 2026.
This content is for information and is not tax advice. If your case involves several platforms, earlier years already reported or doubts about valuation, check it with an adviser.