Spanish tax authorities have sent requests for information on cryptocurrency investors to over 60 companies, a source at the country's tax agency confirmed to CoinDesk following reports in local media.

According to the source, authorities have contacted 16 banks, around a dozen cryptocurrency exchanges and companies operating cryptocurrency ATMs and more than 40 businesses that accept online cryptocurrency payments.

The agency is seeking granular information about cryptocurrency transactions and the parties involved in their execution. Requested details include the identities of the businesses' clients, bank account and credit card information and the amounts and exchange rates involved in transactions.

The tax agency source described the data requests as a prelude to potentially more formal investigation and monitoring, adding that the agency is already carrying out analysis on domestic cryptocurrency use.

The news comes amid a heightened interest among global tax agencies in cryptocurrency, one that follows the market's surge to more than $800 billion in value in Q1 2018.

Further, in Spain, the news tracks efforts from the finance ministry, which houses the tax agency, to address bitcoin and other cryptocurrencies in an official bulletin published in March. At the time, government officials notably sought to link the technology to organized crime, calling for increased oversight and supervision.

Spanish banknotes via Shutterstock