Crypto reporting obligations: 721, 172/175, 042, DAC8 and CARF
The map of crypto reporting has ceased to be a still picture. The basis currently in operation rests on Law 11/2021, on Royal Decree 249/2023 and on the 2023 ministerial orders that approved Form 721 and Forms 172 and 173; that block remains the reference for the years prior to the new regulatory development. But Spain has already put out for public consultation, between 10 and 30 March 2026, a draft order that reorders the system: it introduces the census Form 042, for registration, amendment or cancellation in the Register of crypto-asset providers —which affects certain providers not subject to MiCA, not the individual investor—, keeps Form 172, replaces Form 173 with a new Form 175 and re-approves Form 721 with a new technical architecture. It also updates Form 289 on financial accounts (CRS) to align it with DAC8. The new block would apply for the first time to the 2026 tax year, with filing from 2027. It should be noted that, as of today, the consultation stage having now concluded, the draft has not yet been approved or published in the BOE, so its content may change. The practical consequence is that one must distinguish, at all times, between the rules applicable to past years and the rules planned or to be applied going forward.
Form 721: crypto-assets abroad, with a decisive nuance
Form 721 is a reporting obligation on crypto-assets located abroad. But that formulation requires precision. The decisive point is not the blockchain in the abstract, nor the place from which the user accesses their wallet, but the existence of a third party providing a private-key safeguarding service on the holder’s behalf. Put another way: the analysis does not turn on “where the bitcoin is”, but on whether there is third-party custody and on whether that provider is or is not subject to the Spanish reporting obligation. Virtual currency is deemed located abroad when the custodian of the keys is not required to report in Spain (Forms 172/173), not by reason of the provider’s mere geographical seat. Pure self-custody calls for a different reading and does not admit simplistic assertions. So confirms the Directorate-General for Taxes itself: for the purposes of Form 721, only virtual currencies held in custody by a third party safeguarding the private keys on the holder’s behalf are counted; those kept in self-custody, where the holder controls their own keys, fall outside the obligation (DGT V2290-23, of 28 July 2023; art. 42 quater of the General Regulation on Tax Management and Inspection, RD 1065/2007, as worded by RD 249/2023). A quantitative threshold is added to this: Form 721 need only be filed where the combined balance of the virtual currencies held in custody by third parties abroad exceeds 50,000 euros as of 31 December, or on the date of extinction or cessation of the holding, pursuant to art. 42 quater.5 of the RGAT. Below that threshold —and always in self-custody— no obligation arises.
Forms 172 and 175 are obligations of the providers, not of the investor
A point often confused: Forms 172 and 173 are not obligations of the individual investor, but of certain service providers, in respect of their clients’ balances and transactions. It is worth distinguishing their respective object: Form 172 reports the crypto-asset balances of the provider’s clients, whereas Form 173 —and its successor, Form 175— reports the transactions (acquisitions, transfers, swaps, transmissions, collections and payments) in which the provider intervenes or acts as intermediary (arts. 39 bis and 39 ter of the RGAT). And here a feature of the 2026 transition appears: the draft put out for public consultation provides that the former Form 173 will be displaced by a new Form 175, adapted to the DAC8 framework. That changeover is relevant because it affects the information the authorities will receive and the identification of the party required to supply it.
DAC8 changes the scale of the analysis
DAC8 does not merely add one more form. It brings into the European sphere the automatic exchange of information on crypto-assets, the due-diligence rules and the registration obligations of certain providers, in line with the international CARF standard. It therefore requires leaving behind a purely domestic view of reporting. The tax visibility of crypto activity no longer depends only on Spanish custodians or isolated national obligations: it is moving towards an environment of European and international standardisation in which information on users and transactions is, structurally, far more traceable.
A methodological caution is in order, however. An increase in reporting is not equivalent to a substantive resolution of the underlying tax questions. The authorities’ having more data improves their auditing capacity, but does not replace the legal analysis of the characterisation of the income, the location of the asset or proof of the acquisition cost.
The practical consequence: documentary consistency moves to the foreground
For the taxpayer with accounts on centralised platforms, third-party custody, custodial staking or balances on foreign exchanges, the recommendation is not only to declare correctly, but to keep a coherent documentary file: annual statements, transaction exports, relevant screenshots, the euro-valuation methodology and, where applicable, the traceability between internal accounts and one’s own wallets. The discrepancy between that file and the information circulating through the 172 / 175 / 721 / DAC8 circuit is one of the real risks worth anticipating.
The crypto ecosystem is moving from a taxation that is hard to verify towards one that is increasingly verifiable. That shift does not eliminate the doctrinal grey areas, but it severely reduces the practical viability of disorderly, poorly documented or internally incoherent activity. The adviser’s role no longer stops at explaining what is taxed: it extends to making the taxpayer’s position evidentially defensible when the reporting starts to speak for them.