Conference Agenda

Platforms are increasing in importance in the digital economy. Year-on-year growth in social media accounts is nearly 5% globally (Jackson, 2026, Feb. 2). The global ecommerce platform market is growing nearly 13% annually (Markets And Markets, 2025). Platforms such as Microsoft Azure and Amazon AWS offer tools for data science and AI applications. Global app downloads between 2014 and 2024 exceeded one trillion. As these digital ecosystems expand, users and government officials increasingly scrutinize their conduct. Antitrust cases in the US and the Digital Markets Act in the European Union reflect a growing interest in government oversight.

At the center of this discussion is the "dual role" of digital platforms—specifically, how a platform owner (such as Apple or Google) affects platform users when the owner becomes a user. Critics frequently argue that vertically integrated platforms possess both the incentive and the means to engage in anticompetitive behavior, notably "self-preferencing," wherein a platform gives its own products favorable. Proponents of regulation argue that this suppresses rival startups, raises prices, and ultimately stifles innovation. Others argue that owners take greater interest in platform success when the owner is also a user.

The effects of owners-as-users is ultimately an empirical question. This paper investigates this issue by considering the effects of mobile platforms’ presence in their own app stores, i.e., Apple’s supplying apps on the iOS platform and Google supplying apps in its Play Store on the Android platform. Using a difference-in-differences approach on a rich monthly panel dataset sourced from Sensor Tower, a leading mobile analytics firm, we consider the effects of owner entry on global and U.S. downloads, number of updates, price of the app at the end of month, and estimated app revenue from app sales and in-app purchases only. A major challenge is accurately identifying the apps that compete with the owner apps. We address this issue by augmenting the Sensor Tower data with crowdsourced information from AlternativeTo.net. We match owners’ apps with their user-identified alternatives and define a granular “Neighborhood" of direct functional substitutes.

We find that the effects of platform owner entry onto its own platform are highly nuanced and heterogeneous across platforms. While we don’t observe strong evidence of active suppression or sabotage, the introduction of a first-party app sometimes significantly alters the business strategies of direct rivals. This is particularly salient in the iOS ecosystem, where Apple’s introduction of its own apps on its platform led to reduced prices and reduced app updates, but rivals’ revenue increased even though their downloads decreased over the long term. As for Google, while we observe a temporary, noisy increase in downloads for rivals' apps after Google introduces its own apps on its platform, but there are no observable changes in prices, update frequency, or revenue for these rivals.

We are conducting further analyses to investigate why these patterns emerge. The differences between Apple and Google might result from these companies’ different business models—Apple is largely a provider of devices whereas Google focuses on software and advertising. With respect to the results for Apple, it might be that Apple’s provision of an app triggers price decreases because of increased competition, but also expands demand, leading to increased revenue for rivals. Developers’ non-responses to Google entry might imply that, in general, Google is not seen as a significant rival.