Consumer multi-homing is considered to be critical for competition policy regarding digital platforms. To assess the role of consumer multi-homing in competition policy toward platforms, we develop a new framework that embeds consumer multi-homing in two-sided market into the otherwise standard...

Due to the presence of network externalities in multi-sided markets, evaluating the performance of a platform is more difficult than for a firm in a traditional market. In this paper I develop methods for determining platform marginal costs, market power, and post-merger price predictions. I...