X Internet Unlimited Company (XIUC), known until the start of April 2025 as Twitter Internet Unlimited Company (TIUC), was notified last week of the regulator’s decision to conduct an inquiry under section 110 of the Data Protection Act 2018.

The inquiry will focus on the processing of personal data comprised in publicly-accessible posts posted on X by EU/EEA users, for the purposes of training generative artificial intelligence models, in particular the Grok large language models (LLMs).

It will examine compliance with a range of key provisions of the GDPR, including with regard to the lawfulness and transparency of the processing.

Grok is the name of a group of AI models developed by xAI.

These LLMs are used, among other things, to power a generative AI querying tool/chatbot, which is available on the X platform.

Like other modern LLMs, the Grok LLMs have been developed and trained on a wide variety of data.

“This inquiry considers a range of issues concerning the use of a subset of this data which was controlled by XIUC, namely personal data comprised in publicly accessible posts posted on the X social media platform by EU/EEA users,” the DPC said on Friday.

“The purpose of this inquiry is to determine whether this personal data was lawfully processed in order to train the Grok LLMs.”

The decision to conduct the inquiry was taken by data protection commissioners Dr Des Hogan and Dale Sunderland.