This paper deals with collusive risks that can result from the ecosystems created by digital platforms. Recent case reports reflect that the potential for harm and benefit can be tightly interwoven here. It is not entirely clear, however, in what way the creation of a platform can, in itself, amount to a breach of the cartel prohibition, and how the potential for harm can be balanced against efficiencies in those cases. I argue in favour of an integrated construal of conduct and effect in order to close regulatory gaps whilst preventing false positives.