This article summarizes three quantitative pieces of analysis using large transaction-level datasets that the CMA undertook in a recent market study into online platforms and digital advertising. These are: a comparison of Google and Bing’s search advertising prices; an analysis of Google’s fees from providing advertising intermediation services; and an assessment of the value of targeting digital advertising through the use of third-party cookies. We find that Google’s search advertising prices are 30-40 percent higher than Bing’s on a like for like basis, while Google’s fees for advertising intermediation services are broadly comparable with those of its competitors. Regarding the value of user data for targeting, we find that blocking access to third-party cookies reduces publisher revenue by around 70 percent. We expect that this form of analysis will become an increasingly important aspect of regulatory oversight of digital markets in the future, as it can provide highly valuable insights into the working of the often-opaque algorithms that increasingly drive digital market outcomes.

By Simeon Thornton, Chris Jenkins, Giacomo Mason & Dan Griffiths1



The Competition and Markets Authority (“CMA”) conducted a market study into online platforms and digital advertising in the UK between July 2019 and July 2020.2 Our aim was to assess the state of competition in the sector, and to analyze the sources and implications of market power


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