Spanish residents holding any cryptocurrencies on overseas platforms must declare those assets by March 31st, 2024 under newly published regulations. The mandate comes as Spain moves to tighten oversight of virtual currencies.

The declaration requirement applies to individuals with over  €50,000 worth of crypto across foreign exchanges or wallets. The Spanish Tax Authority's new Form 721 filings open January 1st, with disclosures of holdings as of December 31st, 2023.

Companies must also report foreign crypto accounts surpassing the value threshold by end of first quarter 2024. Failure to declare overseas digital asset ownership could trigger penalties.

Spain has recently increased warnings to citizens on paying owed taxes for domestic crypto investments. Warnings surged 40% last year to 328,000 notices about unreported 2022 holdings.

As virtual currencies gain adoption across Europe, Spanish authorities aim to govern the emerging sector through proactive policies like mandatory disclosures rules. The country plans implementing the EU's sweeping crypto regulations by end of 2025 — six months ahead of deadline.