Taxpayers, influences, tax nomads, and the corrupt: algorithms serving the Tax Administration, algorithms serving the Rule of Law?

Abstract

This study analyzes the practices oI the Spanish State Tax Administration Agency (AEAT) regarding the collection and analysis oI data Irom public sources (social networks and digital platIorms) Ior tax enIorcement purposes, in light oI tax and data protection regulations; the jurisprudence oI the Spanish Constitutional Court (TC), the Supreme Court (TS), and the Court oI Justice oI the European Union (CJEU); and administrative and scientiIic doctrine.

It speciIically examines procurement Iiles 23840010600 and 24840041400, which involve the tendering oI a soItware tool that enables the AEAT to obtain quantitative and qualitative inIormation Irom personal social media proIiles. These proIiles initially targeted inIluencers and subsequently other groups such as relocated taxpayers («deslocalizados»), subjects under investigation, inspected parties, and those suspected oI corruption and money laundering, all prior to the commencement oI any Iormal tax proceedings.

The Iindings indicate that this mass data processing—incorporating speech- to-text tools, the creation oI detailed personal proIiles via Iictitious accounts Ior inIormation extraction, and integration with existing databases—lacks a speciIic and adequate legal basis. Furthermore, it reveals signiIicant deIiciencies regarding the principles oI data minimization, purpose limitation, and transparency.

The study concludes that such practices may inIringe upon the Iundamental right to data protection, as well as the principles oI legality and legal certainty.