Microsoft faces lawsuit over allegations of unlawful data processing for advertising

In May, the Irish Council for Civil Liberties obtained High Court approval deeming its action admissible as a representative action under the 2023 Protection of the Collective Interests of Consumers Act — the first such case to be brought under that act

It is claimed that Microsoft's 'search and news advertising' business generated some $10.2bn (€8.6bn) in the nine months ending March 2025. Picture: AP

Microsoft Ireland Operations is being sued in the first ever High Court representative action under new legislation over its alleged unlawful processing of personal data which generates billions in advertising revenue.

The Irish Council for Civil Liberties (ICCL) has brought the action claiming Microsoft operates an advertising business, through its Xandr platform, which allows it to sell advertising slots to individual advertisers in a real-time bidding system for a fee.