The European Commission has started a formal antitrust investigation into Google over whether the company unfairly favours its own online display advertising technology over competitors. The European Commission's executive vice-president Margrethe Vestager said: 'We are concerned that Google has made it harder for rival online advertising services to compete in the so-called ad tech stack'. The investigation will assess whether Google is distorting competition by restricting access by third parties to user data for advertising purposes and meanwhile reserving this data for its own use. Google operates at all levels of the supply chain for online display advertising: a.it collects data to be used for targeted advertising purposes; b. it sells advertising space; c. it also acts as an online advertising intermediary. The in-depth investigation on Google's practices will focuses among other measures on:

1. The requirement to use Google's services Display & Video or Google Ads to purchase online advertisement placement on YouTube;
2.  The requirement to use Google Ad Manager to place online advertisement on YouTube and potential restrictions imposed by Google;
3.  The restrictions imposed by Google on third parties to the access of data about users' identity or behaviour. Such information is available to Google's own advertising services.

The practices under investigation may violate EU competition law, including rules on anticompetitive deals between companies and on the abuse of a dominant position (articles 101 and 102 of the Treaty on the Functioning of the European Union).