Self-custody excluded from Form 721
Spain’s Agencia Tributaria explicitly distinguishes between custodial and non-custodial wallets, as Europe strengthens its crypto compliance requirements. The decisive factor is not whether the wallet is “hot” or “cold”, but who controls the private keys.
When users hold their own keys, the cryptoassets are not considered to be held on their behalf by a foreign provider. They are therefore excluded from the Form 721 calculation. Spain’s tax administration clearly states that these assets do not have to be reported under this framework.
This distinction provides a fairly concrete administrative advantage for self-custody. It comes as Europe simultaneously strengthens its crypto compliance requirements.
There is, however, an important caveat: Spain has not made self-custodied crypto “invisible to the tax authorities”. The rule applies only to this specific informational filing concerning virtual currencies held abroad. A sale generating a capital gain may still have tax consequences depending on the taxpayer’s situation.
The private key therefore changes the Form 721 reporting obligation. It does not eliminate tax.
The €50,000 threshold still applies to foreign exchanges
The situation changes when cryptoassets are held by an exchange or custodian located outside Spain.
According to the Agencia Tributaria’s official documentation, Form 721 applies in particular to Spanish residents who own, control or benefit from virtual currencies held by a foreign company responsible for safeguarding the private keys. The assets are considered to be “located abroad” when the provider responsible for their custody is not subject to the corresponding Spanish reporting obligations.
The threshold is set at €50,000.
If the combined value of the relevant virtual currencies does not exceed €50,000 on 31 December, no Form 721 filing is required. Once the threshold is exceeded, all the relevant cryptoassets must be reported, not just the portion above €50,000.
In subsequent years, the filing generally only has to be renewed if the balance on 31 December increases by more than €20,000 compared with the balance that triggered the previous filing. The form must be submitted between 1 January and 31 March of the following year.
This administrative tightening is part of a much broader European shift. The EU is already seeking to strengthen the tax framework for direct crypto holdings, while DAC8 is gradually increasing the amount of information collected from service providers.
One additional detail deserves attention: euros or dollars left on a foreign exchange do not fall under Form 721. However, under certain conditions, they may fall within the scope of Form 720, which also has a €50,000 threshold.
Selling before December may avoid the filing
The most interesting rule concerns cryptoassets bought and then sold in full during the same year.
Spain’s tax administration gives this precise example: a person buys virtual currencies held abroad for the first time, their value temporarily exceeds €50,000, and the person then sells all of them before 31 December.
They do not have to file Form 721 for those assets.
Why? Because no reporting obligation had previously arisen for those cryptoassets.
The situation is different when a position was already reported in a previous year. If the taxpayer subsequently sells those assets before 31 December of a later year, the disappearance of the position must be reported on the corresponding Form 721.
This is the nuance lost in the formula “sold before 31 December = no filing”.
Spain is therefore not creating a general exemption for short-term traders. Its system is built around a snapshot of foreign holdings, their custody arrangements and the history of previous filings.
This distinction between custody and self-custody is also becoming a regulatory issue well beyond taxation. In the United States, several bills are likewise seeking to explicitly protect personal crypto custody.
For Spanish holders, the rule is now fairly clear: your private keys, your wallet, no Form 721 for those assets. The keys are held by a foreign custodian and the portfolio exceeds €50,000 on 31 December? The filing becomes relevant again.
