Spain's National Securities Market Commission (CNMV) announced on Thursday that it had initiated disciplinary proceedings against X Corp. subsidiary Twitter International Unlimited Company for advertising a company that was not authorized to provide investment services.

The Spanish regulator said the Irish subsidiary failed to check whether Quantum AI was authorized to provide investment services before advertising it on X.

Quantum AI's advertisements on X promised to earn high profits using cryptocurrencies.

In May, the Hong Kong Securities and Futures Commission (SFC) issued a notice warning the public against an entity operating under the name "Quantum AI" that was suspected of engaging in fraudulent activities related to virtual assets.