This paper studies the bundling strategies of two firms that each sell a horizontally differentiated platform and a complementary good. When the complementary goods are vertically differentiated, the firm that sells the superior one can commit to a more aggressive pricing strategy through bundling. In the presence of asymmetry in externalities between the two sides in the platform market, bundling may be profitable without foreclosing the rival when platforms implement cross subsidies from the high-externality side (developers) to the low-externality side (consumers). Bundling has a positive effect on welfare because it allows for better internalization of the indirect network effects and reduces the developer cost of multi-homing, but it also has a negative effect because some consumers consume less-preferred components. Consequently, bundling is socially desirable when platforms are not too differentiated and the vertical differentiation between the complementary goods is high.

中文翻译：

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捆绑，垂直差异和平台竞争

本文研究了两家分别销售水平差异化平台和互补产品的两家公司的捆绑策略。当互补商品在垂直方向上有所区分时，出售上等商品的公司可以通过捆绑销售采取更具侵略性的定价策略。如果平台市场的外部性之间存在不对称性，则当平台实施从高外部性方面（开发人员）到低外部性方面（消费者）的交叉补贴时，捆绑交易可能会获利而不会排斥竞争对手。捆绑对福利有积极的影响，因为它可以更好地内部化间接网络效应，并降低多宿主的开发人员成本，但同时也有负面影响，因为某些消费者会消耗不太喜欢的组件。所以，