On June 22, 2021, the Commission opened a formal investigation into Google’s activities in the online advertising technology (“ad tech”) sector.[1]


Ad tech refers to tools which advertisers use to deliver online ads to end-users on third-party websites or apps. Similar to a supply chain, the ad tech “stack” includes various intermediary steps between the advertiser and the publisher that will ultimately host the ads on their website.[2] The Commission’s investigation focuses on several of those steps:

  • Advertiser ad server. Advertiser ad servers track and manage ad performance on the websites/apps where ads are displayed. Google is active at the advertiser ad server stage through its Google Campaign Manager service.
  • Supply-side and demand-side platforms (“SSPs” and “DSPs”). SSPs run bid auctions on behalf of publishers for the sale of the publishers’ advertising Advertisers participate in these auctions through DSPs, which use automated algorithms to make buying and bidding decisions. Google is active both as an SSP (Google Ad Exchange) and a DSP (Google Display & Video 360 and Google Ads).
  • Publisher ad Publisher ad servers organize and manage ad inventories. The SSPs report the winning bids from the auction to the publisher ad servers.

Figure 1: Ad tech stack and Google’s activities within it according to the ACCC[3]

Practices under investigation

The Commission is investigating whether Google may be favoring its own vertically integrated services across the ad tech stack:

  • YouTube ad-inventory-related practices. YouTube’s ad inventory is sold exclusively through Google’s own ad tech platforms due to privacy The Commission is investigating obligation: (i) to use Google’s DSP services to purchase online display advertisements on YouTube; and (ii) of Google’s publisher ad server to serve online display advertisements on YouTube.
  • Alleged SSP-DSP favoring. The Commission is investigating whether Google’s SSP services favor bids submitted by Google’s DSP services, or vice versa.
  • Privacy The Commission is investigating Google’s announced plans to prohibit the placement of third-party cookies on Chrome and replace them with the “Privacy Sandbox” set of tools.

Restriction of access to user data. The Commission is evaluating restrictions placed by Google on the ability of third parties, such as advertisers, publishers or competing online display advertising intermediaries, to access data about user identity or user behavior which is available to Google’s own advertising intermediation services.

The Commission is also examining Google’s announced plans to stop making the advertising identifier available to third parties on Android smart mobile devices when a user opts out of personalized advertising.

The investigation comes in the context of increased scrutiny of online platforms’ use of data by competition authorities. These investigations raise interesting questions around the interaction between the mandates of privacy and competition authorities. The Commission’s statement acknowledges in this respect that its investigation will “take into account the need to protect user privacy.” The Commission’s approach to this aspect of the investigation is likely to draw significant attention.

The ad tech saga continues

Ad tech services have been subject to increasing regulatory scrutiny. Google recently settled an ad tech investigation in France and has offered commitments in relation to the Privacy Sandbox to the CMA in the UK.[4] On the other side of the Atlantic, the Texas Attorney General filed a complaint in late 2020 before the U.S. Department of Justice on behalf of ten U.S. States, alleging that Google and Facebook have entered into an unlawful agreement to restrict competition across the ad tech stack. The ACCC in Australia is also conducting a market investigation into ad tech practices.

[1]      Commission Press Release IP/21/3142, “Antitrust: Commission opens investigation into possible anticompetitive conduct by Google in the online advertising technology sector,” June 21, 2021.

[2]      An overview of Google’s activities in ad tech is provided in Figure 1.

[3]      The Australian Competition and Consumer Competition Authority (“ACCC”) conducted a report in digital advertising from which this graphic is sourced. ACCC Digital advertising services inquiry – interim report, January 28, 2021, available at: https://www.accc.gov.au/system/files/Digital%20Advertising%20 Services%20Inquiry%20-%20Interim%20report.pdf.

[4]      See, our November 2020 French Competition Law Newsletter, and our January 2021 UK Competition Law Newsletter, respectively.