The UK's Competition and Markets Authority has launched a second investigation into Google's ad tech practices. This probe, in particular, will look into the role Google plays in the "ad tech stack," or the set of services that facilitate the sale of online advertising space between advertisers and sellers like online content providers. The organization explained that Google has strong positions at various levels of the ad tech stack and charges fees to both publishers and advertisers.

It's examining three key parts of the stack in which Google plays key roles, since it owns the largest providers for each. CMA will examine Google's practices for demand-side platforms, which give advertisers and media agencies a way to buy a publishers' space for advertising from many sources. It will also look into the company's practices relating to ad exchanges that can automate the sale of publishers' inventory. Finally, the CMA will examine Google's publisher ad servers that manage a publisher's inventory to decide which ad to show at a given time based on the bids and direct deals for the space.

Google's practices — if indeed questionable — could distort competition, the CMA said. It could contractually tie these various services together, for instance, so users won't have a choice but to go with Google all the way, making it difficult for smaller rival services to compete.

According to Andrea Coscelli, the CMA's Chief Executive:

The organization is also investigating whether Google and Meta colluded over ads. That probe is all about digging into the advertising agreement between the two companies codenamed "Jedi Blue" and figuring out if that deal hinders competition in online advertising.