London, Jun 22 (IANS): The European Commission on Tuesday opened a formal antitrust investigation against Google to assess whether the search giant has violated EU competition rules by favouring its own online display advertising technology services.

According to the EU watchdog, such a move would be detrimental to competing providers of advertising technology services, advertisers and online publishers.

The formal investigation will notably examine whether Google is distorting competition by restricting access by third parties to user data for advertising purposes on websites and apps, while reserving such data for its own use, the commission said in a statement.

Online advertising services are at the heart of how Google and publishers monetise their online services.

"Google collects data to be used for targeted advertising purposes, it sells advertising space and also acts as an online advertising intermediary. So Google is present at almost all levels of the supply chain for online display advertising," said Executive Vice-President Margrethe Vestager, in charge of competition policy.

"We are concerned that Google has made it harder for rival online advertising services to compete in the so-called ad tech stack. A level playing field is of the essence for everyone in the supply chain," she added.

Google is facing a similar antitrust probe in the US as the Justice Department year filed antitrust charges against the company in October last year, alleging that the company illegally monopolises the search and ad markets.

In the last decade, the EU has fined Google over $9.5 billion over various antitrust violations.

According to the commission, many publishers rely on online display advertising to fund free online content for consumers. In 2019, display advertising spending in the EU was estimated to be approximately 20 billion euros.

Google provides several advertising technology services that intermediate between advertisers and publishers in order to display ads on web sites or mobile apps.

"Fair competition is important -- both for advertisers to reach consumers on publishers' sites and for publishers to sell their space to advertisers, to generate revenues and funding for content. We will also be looking at Google's policies on user tracking to make sure they are in line with fair competition," Vestager noted.

The Commission will take into account the need to protect user privacy, in accordance with EU laws in this respect, such as the General Data Protection Regulation (GDPR).