A non-discrimination principle for rankings in app stores

The gatekeeper position of app store operators gives them the power to favour their own and the most popular applications in the rankings of search results. Based on parallels with the non-discrimination principle in the European Union's Regulation on Open Internet Access, this article formulates a list of permitted and forbidden ranking rationales for app store operators. Permitted ranking rationales include text relevance, price, quality and the legality of content. These rationales contrast with the forbidden ranking rationales, such as those based on self-favouring without objective justification and the popularity of applications, which potentially limit consumer choice and distort the digital level playing field.