Regulating Platform Competition in Markets with Network Externalities: Will Predatory Pricing Restrictions Increase Social Welfare?*
研究了网络外部性市场中无限重复的平台竞争，发现对称监管（禁止所有平台掠夺性定价）降低消费者剩余且不影响效率，而非对称监管（仅禁止在位者）在市场大小不变时提高消费者剩余和福利，但市场大小变化时可能导致低效进入。
We consider an infinitely repeated platform competition in a market with network externalities. The platform that dominated the market in the previous period becomes the incumbent in the current period. We examine the effect of an antitrust policy that prohibits both platforms (symmetric regulation), or just the incumbent (asymmetric regulation) from charging predatory prices. We show that symmetric regulation decreases consumer surplus and does not affect efficiency. Asymmetric regulation increases consumer surplus and improves welfare when the size of the market remains constant over time. Yet, when market size varies over time, this policy may lead to inefficient entry.