Sébastien Lamproye
Sébastien
Lamproye
I study how firm market power shapes welfare, market structure, and aggregate economic outcomes.
Research
At the Department of Economics at KU Leuven, I conduct my research in the IO Group under the supervision of Prof. Johannes Van Biesebroeck. I expect to complete my PhD in summer 2027.
My work combines theory and firm-level data to study market power, firm performance, production networks, and misallocation.
My doctoral research is supported by a PhD Fellowship in Fundamental Research from the Research Foundation – Flanders (FWO).
Market Power and Firm-Level Welfare Incidence
Which firms account for the welfare cost of market power? I develop a firm-level welfare-incidence measure that combines markup wedges, firm size, demand curvature, and expenditure reallocation to identify where aggregate welfare losses originate.
Selected work
My broader research studies how distortions propagate through firm networks, how information affects platform competition, and how innovation diffuses across regions.
Working paper
Aggregating Markups in Production Networks
With Emmanuel Dhyne (National Bank of Belgium and University of Mons). An economy-wide measure of market power that accounts for the position of firms in production networks.
Work in progress
When Comparison Makes Markets Tip
With Duy-Anh Phan (Monash University). How comparability can intensify competition while making two-sided markets more likely to tip.
Under review
Technological Knowledge Intensity and Intergenerational Mobility
Evidence on the relationship between patent-based knowledge intensity and upward mobility across U.S. regions.
Work in progress
Patents, Diffusion, and the Gap Between Discovery and Use
With Tselmuun Tserenkhuu (Osaka University). A project on innovation, diffusion, and the use of technological knowledge.
Beyond economics
I began practicing judo at age six and earned my black belt a decade later. In 2025, I became Belgian national champion in the −100 kg category, and I continue to compete and teach judo alongside my academic work.
Contact
Department of Economics, KU Leuven
Naamsestraat 69, 3000 Leuven, Belgium