The conditions under which gatekeepers provide online advertising services to business users, including both advertisers and publishers, are often non-transparent and opaque. This opacity is partly linked to the practices of a few platforms, but is also due to the sheer complexity of modern day programmatic advertising. That sector is considered to have become less transparent after the introduction of new privacy legislation. This often leads to a lack of information and knowledge for advertisers and publishers about the conditions of the online advertising services they purchase and undermines their ability to switch between undertakings providing online advertising services. Furthermore, the costs of online advertising services under these conditions are likely to be higher than they would be in a fairer, more transparent and contestable platform environment. Those higher costs are likely to be reflected in the prices that end users pay for many daily products and services relying on the use of online advertising services. Transparency obligations should therefore require gatekeepers to provide advertisers and publishers to whom they supply online advertising services, when requested, with free of charge information that allows both sides to understand the price paid for each of the different online advertising services provided as part of the relevant advertising value chain.

This information should be provided, upon request, to an advertiser at the level of an individual advertisement in relation to the price and fees charged to that advertiser and, subject to an agreement by the publisher owning the inventory where the advertisement is displayed, the remuneration received by that consenting publisher. The provision of this information on a daily basis will allow advertisers to receive information that has a sufficient level of granularity necessary to compare the costs of using the online advertising services of gatekeepers with the costs of using online advertising services of alternative undertakings. Where some publishers do not provide their consent to the sharing of the relevant information with the advertiser, the gatekeeper should provide the advertiser with the information about the daily average remuneration received by those publishers for the relevant advertisements. The same obligation and principles of sharing the relevant information concerning the provision of online advertising services should apply in respect of requests by publishers. Since gatekeepers can use different pricing models for the provision of online advertising services to advertisers and publishers, for instance a price per impression, per view or any other criterion, gatekeepers should also provide the method with which each of the prices and remunerations are calculated.