Modelo 721 is the younger sibling of Modelo 720 (the Spanish information return on assets abroad), and it resembles it less than the number suggests. It has its own threshold, its own obligation and, above all, a starting condition that leaves out many people who assume they have to file it: you do not declare what you own, you declare what a third party abroad holds in custody for you.
What exactly is declared
The obligation covers virtual currencies located abroad of which you are the holder or beneficiary, or over which you have power of disposal, when two conditions are met: that they are held in custody by persons or entities that provide services safeguarding private cryptographic keys on behalf of third parties, and that those persons or entities are not resident in Spain and have no permanent establishment here.
If you hold the private keys yourself (a hardware wallet, an app in which only you keep the seed phrase), there is no third party holding them in custody, and without a third-party custodian the condition for this information obligation is not met. It is the nuance almost nobody mentions, and it changes the answer in many cases. Be careful about taking it as read from memory: some services look like self-custody and are not, and the reverse. It is checked by reading the provider's terms, not its brand name.
The threshold, which is combined and not per currency
There is no obligation to report when the balances at 31 December of the various virtual currencies, valued in euros, do not together exceed €50,000. In other words: you do not look currency by currency or platform by platform; you add up everything held abroad in third-party custody. And if the threshold is exceeded, everything is reported, including the small balances.
| Position at 31 December | Is Modelo 721 due? |
|---|---|
| €32,000 on one foreign exchange and €12,000 on another | No: together they come to €44,000 |
| €40,000 on one foreign exchange and €15,000 on another | Yes, and both are declared |
| €90,000 in a wallet whose keys only you hold | No, because there is no custodian |
| €60,000 on the usual Spanish platform | Not on Modelo 721: the provider is resident |
What information it contains
For each virtual currency you identify the person or entity holding it in custody, with its address and country, and you enter the balances at 31 December expressed in units of that currency together with their value in euros. That double figure (units and amount) is the difference from the accounts section of Modelo 720, where what sit side by side are the year-end balance and the average balance.
The value in euros must be capable of justification. It is worth choosing a price source and sticking to it year after year, and keeping the screenshot or report the figure comes from. Changing reference every tax year produces artificial variations, and on a return made of data, artificial variations end up being explained in writing.
It is also wise to keep statements in the format the platform generates them in, not as a screenshot: a statement identifying the user and the date is evidence, and a cropped image is not. Some providers close old accounts or change hands, and the history is lost without warning.
Deadline and method
From 1 January to 31 March of the following year, online, just like Modelo 720. And like Modelo 720, there is nothing to pay: filing it costs no tax.
Modelo 721 is not Modelo 172 or Modelo 173
This is where almost everybody gets confused, because the three forms deal with the same subject and are filed by different people:
| Form | Who files it | What it reports |
|---|---|---|
| 721 | The holder of the virtual currencies | His or her balances abroad at 31 December |
| 172 | Service providers subject to the obligation in Spain | Their users' balances |
| 173 | The same providers | Acquisitions, disposals, exchanges and transfers |
The practical consequence is uncomfortable and has to be accepted: if you trade through a platform subject to those obligations, the tax authority already has your balances and your transactions by another route. In those cases Modelo 721 is not telling it anything new; what it does is close the loop on what lies outside its reach.
And two things that get confused need to be kept apart: Modelo 721 reports balances on a given date, whereas what is taxed are the year's transactions. You can be obliged to file Modelo 721 without having made any gain, because the balance sat there untouched all year; and you can be under no obligation to file Modelo 721 and still owe a significant amount in income tax, because you traded heavily and ended the year with a small balance. They are two obligations that travel in parallel and are met, or breached, separately.
Reporting does not replace what is taxed
Filing Modelo 721 does not declare any income, and not filing it does not exempt you from declaring it either. Every sale, every swap of one currency for another and every payment made in cryptocurrency produces a capital gain or loss that goes on the income tax return for the year in which it happens, even if nothing has been converted into euros. This is the confusion that costs the most money: believing that as long as nothing is withdrawn to a bank account there is nothing to declare.
Exchanging one virtual currency for another is a swap, and it produces its gain or loss in the tax year in which it is made. Someone who has traded a lot has hundreds of transactions to match in order and by method, and rebuilding that three years later is expensive. If the history is large, the first thing we do is the traceability work, before the form.
Who else may be obliged
It is not only a matter for private individuals with a crypto portfolio. The obligation reaches individuals and legal entities resident in Spain and the Spanish permanent establishments of foreign entities, and not only the holder: also anyone listed as a beneficiary or with power of disposal over the virtual currencies.
That nuance about capacity is what turns people who do not feel they own anything into declarants: whoever manages a relative's keys, whoever runs an account for a project in someone else's name or whoever keeps power over a balance they regard as belonging to someone else. As with Modelo 720, what is declared is not economic ownership, it is the legal position you hold.
The inventory work, which is 90 % of the matter
Filling in Modelo 721 takes little time. What takes time is knowing what has to go on it, and that inventory is built from a specific list:
- Every platform used during the year, including those opened and then abandoned.
- Where each provider is established and whether it holds keys on behalf of third parties.
- Balances at 31 December per currency, in units, with the statement that backs them up.
- The price source used to value them in euros, the same one for all of them.
- Self-custody wallets, which are listed even though they do not go on the form, because the decision not to declare them has to be explainable.
Modelo 721 looks at 31 December, so a balance moved that month to another platform or to your own wallet changes the snapshot on the form. What it does not change is the taxation of the year's transactions, which have already happened, nor the information the provider may have supplied on its own account. Emptying the account before the year ends is one of the manoeuvres that ages worst.
The borders with Modelo 720
Not everything that sounds like crypto goes on Modelo 721. Two frequent cases:
- An exchange-traded fund or a financial product linked to cryptocurrencies, bought through a foreign broker, is not a virtual currency held in custody: it is a security, and it belongs in the corresponding block of Modelo 720. We explain it in how to fill in Modelo 720.
- A balance in euros or dollars sitting idle on a foreign exchange raises the question of whether it is an account or not. It depends on the nature of the service and of the provider, and it is one of the questions we prefer to analyse case by case rather than take for granted.
And there is a third border, a newer one: assets that are securities represented using distributed ledger technology. There the classification is not always obvious, and saying otherwise would be selling certainty where there is debate.
If you did not file it
Modelo 721 is an information return, so failure to file it is penalised under the general rules of the Ley General Tributaria, the Spanish General Tax Act, just like Modelo 720 after Ley 5/2022. Filing late on your own initiative, before any request from the tax authority, is not the same as filing afterwards: the difference is explained in the penalty regime today and in what counts as a prior request.
How we work on it
We start with the map: which providers, where they are, who holds the keys and what balances there were at 31 December. With that we decide whether there is an obligation, and only then is the form built. In parallel, if there is a history of transactions, we reconstruct the traceability for the income tax return, which is where the money is really paid. We do not promise that the classification of a particular product will be uncontroversial; we do promise to tell you when it is not. The form for this line also takes cryptocurrency cases.