Title：Search Prominence among E-Commerce Platforms

Speaker：Yi Zhu(the University of Minnesota.) 

Time: 10:00(Wednesday) , May 27, 2026

Venue: Room 706, Mingde Business Building (Zhongguancun Campus)

Language: English

Abstract：

Prominent platforms such as Amazon, Airbnb, Etsy, and Zalando consistently attract significant consumer search traffic, and have become the default choice for many shoppers. The increasing prominence of these platforms raises concerns about potential adverse effects on both consumers and sellers operating on them. This paper investigates the impact of prominence among e-commerce platforms on market dynamics, while accounting for seller competition within and across platforms. Using a simultaneous search model, we examine a novel tension stemming from platform prominence: a platform differentiation effect, which makes demand on the prominent platform more elastic, and a sorting effect, which gives prominent sellers a more captive set of consumers with high evaluation costs. We show that product complexity determines which outcome prevails, thereby explaining why prominence can push platform sellers to either raise or lower prices. We further identify conditions under which the acquisition of prominence by an e-commerce platform raises or lowers consumer surplus and seller profits. This leads to a simple empirical test for prominence’s pro-competitive effect using only trends in price data from the prominent platform.