Competition and Defaults in Online Search (with Francesco Decarolis and Filippo Paternollo) [ American Economic Journal: Microeconomics (2025)] {VOX Columns}
Sharing Economy Platforms in the Face of Crises:A Conceptual Framework (with Paul Belleflamme and Anaïs Périlleux) [ Sustainability (2025)]
Self-Preferencing in Adjacent Markets [ Competition Policy International (2025)]
Regulating Online Search in the EU: From the Android Case to the Digital Markets Act and Digital Services Act (with Francesco Decarolis) [ International Journal of Industrial Organization (2023)]
Do Lower Search Costs Benefit Intermediaries? [Review of Industrial Organization (2023)]
Competition, Defaults, and Antitrust Remedies in Digital Search (with Francesco Decarolis) [ Competition Policy International (2022)]
Gatekeepers and Self-Preferencing: Incentives and Welfare Trade-offs in Two-sided Markets (with Francesco Decarolis) [CRESSE- CPI Young Researchers Awards 2024][EODS Awards, University of Pennsylvania] {EODS Blog}
Abstract: We study a two-sided platform where a dominant gatekeeper supplies both a primary product and a competing ancillary service. By degrading outcomes for users of rival ancillary services, the gatekeeper engages in cross-market self-preferencing. Our theoretical model identifies when such behavior raises or lowers welfare, depending on buyers’ and sellers’ preferences and the platform’s pricing instruments. Analyzing a recent antitrust case against Google, we show that remedies targeting only one side can misalign incentives between different user groups, reducing welfare. Counterfactual simulations highlight when alternative behavioral or structural interventions realign incentives and improve market efficiency.
When Do Platform Mergers Benefit Users? The Role of Multihoming, Network Effects and Post-Merger Strategies (with Filomena Garcia) [Best Digital Economies Paper Award in Conferência Digitalização na Economia]
Abstract: This paper examines mergers in a setting where two differentiated platforms connect users and remain active after the merger. We highlight the critical interplay between network effects, multihoming, and post-merger strategies. When users on both sides are singlehoming, mergers reduce user surplus, and network effects do not alter this conclusion. By contrast, when one side multihomes, network effects become decisive: strong network effects can flip the welfare impact from negative to positive. We further examine post-merger strategies such as integration and bundling, showing that they can reduce—or even fully eliminate—the potential welfare gains from mergers.
Abstract: Existing research states that an increase in interest rates discourages better borrowers, resulting in a higher default rate. We observe the opposite from analyzing a recent interest adjustment on a peer-to-peer lending platform: borrowers defaulted less after a higher interest rate. To understand the underlying driving force of the borrowers’ behaviors, we model a borrower’s decision to take up the loan and her per-period payment strategy in a dynamic model after taking up the loan. We prove that unobserved default risk alone cannot explain such a data pattern. To rationalize such a counterintuitive data pattern, we introduce another imperfect information besides the borrowers’ default risk. Specifically, the borrowers’ perceptions of payment could differ; some are aware of the prepayment option, but some are inattentive to this option. Such behavior bias helps rationalize the counterintuitive pattern because a rising interest rate discourages naive borrowers from taking up loans more than their sophisticated counterparts. At the same time, naive borrowers’ default rate is higher than sophisticated borrowers due to the prepayment option.
Platform Management (with Paul Belleflamme and Filomena Garcia)
Abstract: The rapid development of information technology enables digital platforms to employ a wider set of fee instruments and assume additional roles beyond being a pure marketplace. In this paper, we investigate these two aspects and their interactions. Employing a unified framework, we demonstrate that there are multiple choices of fee combinations that allow the platform to achieve optimal profit. Second, by evaluating the impact of fee instruments on the platform’s control over user participation, we clarify the relationships among them and propose an innovative method to categorize platforms. Third, we highlight that a platform’s managerial decision to take on additional roles in the digital market is jointly determined by its available fee instruments and how the additional role affects its market.