Challenging merger control: the gravitational pull of digital ecosystems and the promise of entrenchment theory

Traditionally, ecosystem mergers have been assessed through “foreclosure”: whether competitors are excluded from inputs or customers. In Booking/eTraveli and Microsoft/Activision Blizzard, the concern was that acquiring a complement would reinforce the purchaser's dominance (the ecosystem's “gravitational pull”). The parties called this “reverse leveraging”; the Commission framed it as foreclosure; the General Court upheld it in Booking Holdings. The draft EU Merger Guidelines now recognize “entrenchment” as a separate theory. These theories form a continuum: foreclosure requires exclusionary conduct; entrenchment requires none; reverse leveraging requires conduct but not exclusion. The article argues that these are distinguishable through a three-part test: (1) the gateway: are the target's assets strategically important?; (2) structural entrenchment: is the target's contestability extinguished?; (3) conduct-based harm: does conduct deepen the merged entity's position or use the target to weaken competitors? Recognizing reverse leveraging and distinguishing structural from conduct-based mechanisms would make merger analysis more coherent and predictable.