Privacy International has filed complaints against Acxiom, Oracle, Criteo, Quantcast, Tapad, Equifax and Experian over data protection issues.
Privacy International logged the complaints with the French, Irish and UK authorities.
The complaints read: "Together these companies profit from the exploitation of the personal data of millions of people in the UK, in the rest of the European Union and further afield," and that the data protection infringements documented in the complaints represent "the tip of the iceberg" of the companies' malpractice.
Privacy International split the complaints in three groups: data brokers Acxiom and Oracle; adtech companies Criteo, Quantcast and Tapad; and credit-referencing agencies Equifax and Experian.
In the complaint against ad-tech companies, Privacy International noted its concern with Acxiom products InfoBase, Personicx and LiveRamp IdentityLink.
Privacy International has also taken issue with the Oracle Data Cloud. Oracle declined to comment. Acxiom has not responded to The Drum's request for comment.
Privacy International listed concerns over various products from the three adtech companies. One concern the group flagged is profiling, which Privacy International claims to be at the core of what the ad-tech companies do and is direct violation of GDPR regulations.
Criteo and Tapad have not yet responded to The Drum's request for comment. Quantcast declined to comment.
The complaint against credit referencing agencies focuses around "Experian's processing of personal data for marketing purposes," and Equifax's marketing services.
Equifax declined comment. Experian has not responded to The Drum's request for comment.
In a statement, Privacy International said, "In practice, the real test for GDPR will be in its enforcement."