Ammon News - Spain's securities regulator said Thursday it has fined social media platform X five million euros for failing to comply with rules governing advertising of financial products, including cryptocurrencies.

In an official bulletin, the CNMV said the $5.8-million fine was imposed for "a very serious ongoing violation".

The regulator had launched an investigation in November 2023 after detecting advertisements on X promoted by an unauthorized financial company, Quantum AI, which was marketing cryptocurrencies.

The postings violated a regulation introduced in March 2023 requiring websites, media outlets, and social networks to better control advertising of financial products, the CNMV said.

Under the rules, online platforms in Spain are legally required to verify that advertisers are not on lists of illegal companies and that they are authorized to offer financial services, Rodrigo Buenaventura, the CNMV president at the time, said in November 2023 when announcing the probe.