Smaller Slices of a Growing Pie: The Effects of Entry in Platform Markets
研究了新企业进入平台对在位企业的净效应，发现市场扩张总体上有利于在位者，但高质量企业销售和收入显著增长，低质量企业则表现更差。
Entry of new firms onto a platform has an ambivalent effect on the incumbent firms operating on the platform: the main tension lies between the negative effects of increased competitive pressure and positive indirect network effects. This paper empirically studies the net effect of these countervailing forces and its dependence on firm quality, using a quasi-exogenous shock on a large online platform. On average, market expansion favors incumbents, though the average effect masks substantial heterogeneity: high-quality incumbents experience significant increases in sales and revenue, whereas low-quality firms perform unambiguously worse. Lastly, the paper explores the main mechanisms and firms’ responses.