Working Papers
"Asymmetric Price Competition on Hybrid Platforms: Theory and Evidence from Amazon", joint with Luise Eisfeld and Li Yu, August 2026
We study how hybrid platform operation, in which a platform competes with third-party sellers while charging a commission on their sales, shapes pricing incentives. Our model identifies two channels induced by the ad valorem commission - revenue sharing and double markup - that generate asymmetric pricing behavior between the platform and third-party sellers. Using data from Amazon's U.S. marketplace, we find patterns consistent with the model's predictions: third-party prices respond modestly more strongly to third-party entry and exit than to Amazon entry and exit, and significantly more strongly than Amazon prices do to common commodity cost shocks.
"Mandating Interoperability in Messaging App Markets", joint with Mudit Dhakar
This paper investigates how mandated interoperability affects market contestability and consumer welfare in messaging app markets where consumers can multi-home. We develop a simple model of direct network effects with two vertically differentiated apps: a free incumbent with a large installed base and a paid niche app lacking an installed base but offering superior privacy protection. The niche app chooses between a Mass Strategy, which leverages the proprietary network value generated by its exclusive users to reach a broad user base, and a Niche Strategy, which monetizes its quality advantage more directly by targeting only single-homing users. As interoperability increases, the niche app may switch from the Mass Strategy to the Niche Strategy. By eroding the proprietary network value generated by the niche app's exclusive users, intermediate levels of interoperability can hurt the niche app when the incumbent's installed-base advantage is modest. Our analysis also highlights a potential tension between promoting market contestability and enhancing consumer welfare.
"Data, Targeted Advertising and the Quality of Journalism: The Case of Accelerated Mobile Page (AMP)", joint with Doh-Shin Jeon
This paper studies how newspapers’ adoption of Google’s Accelerated Mobile Page (AMP), a publishing format for mobile devices enabling instant loading of web pages, changes data allocation and thereby newspapers’ incentive to invest in the quality of journalism when consumer data is used for targeted advertising. The adoption of AMP allows Google to obtain consumer data from AMP articles and to combine it with other sources of consumer data to improve the targeting of the advertisements served by Google on other websites. Even if such data combination increases static efficiency, it can reduce dynamic efficiency when it lowers the ad revenue per newspaper traffic and thereby reduces the quality of journalism. Newspapers face a collective action problem as a newspaper’s adoption of AMP generates negative externalities to other newspapers through data leakage. In addition to leveraging its search monopoly power, Google can use a divide-and-conquer strategy to induce newspapers to adopt AMP. We provide policy remedies.
"Vertical Integration and Foreclosure in Two-Sided Markets"
This paper studies vertical foreclosure issue in platforms characterized by bilateral cross-group network externalities. I focus on an environment where the monopolistic platform and downstream sellers face uncertainty over the gains from trade at the contracting stage. As the random shock is non-contractible, contracting creates friction which distorts the platform’s pricing structure. By contrast, vertical integration mitigates this problem by allowing the platform to incorporate the random shock in consumer pricing. Due to the interaction between transaction friction and cross-group network externalities, I find that vertical integration could reduce the platform’s incentive of foreclosure.
Work-in-Progress
Digital Copyright: Search Engine’s Use of Snippets