We study the price and welfare effects of a merger of firms producing unidirectional complements: a firm is producing a product (called an optional good) that is valuable only if it is consumed with the other product (called a base good) produced by another firm. Under the assumption that there...

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...