Horizontal and Vertical Interoperability in the DMA

The latest CERRE issue paper on the DMA discusses some key issues and trade-offs that may arise in implementing the horizontal and vertical interoperability provisions of the regulation.

This paper, authored by CERRE Academic Co-Directors Jan Kraemer and Marc Bourreau, builds on two previous CERRE papers, the 2022 CERRE report “Interoperability in Digital Markets”, which discusses the pros and cons of mandating horizontal and vertical interoperability from an economic perspective, and the 2023 CERRE paper “DMA Horizontal and Vertical Interoperability Obligations”, which addresses several issues of scope and implementation related to interoperability.

The authors first discuss the implementation of the horizontal interoperability provision in the DMA (Article 7). They argue, on the one hand, that horizontal interoperability will require proper management of user consent and careful interface design and, on the other, that achieving horizontal interoperability poses significant technical challenges to:

• resolve identities across providers;
• establish secure connections; and
• deal with malicious users. Solving these technical challenges will raise trade-offs for which there are no easy choices.

Second, they briefly discuss general principles for the implementation of vertical interoperability provisions, i.e., specifically Articles 6(4) and 6(7). Here, they argue for five principles:

• screening of access requests,
• screening of access seekers,
• gatekeeper-led definition of interfaces,
• equivalence of input, and
• a neutral choice architecture.

The authors also emphasise that there can be interactions between the four principles so that they must be evaluated in concert, and not in isolation.

This issue paper is part of a broader CERRE project on the European Union’s Digital Markets Act.