PhD Thesis

Infrastructure Sharing in Network Industries

Supervised by Marc Bourreau and Lukasz Grzybowski

Working Papers

Co-invention and knowledge transfer in science-industry collaboration: Evidence on Recombinant Novelty

Si Hao Li, Anne Plunket and Felipe Starosta de Waldemar

Working Paper Accepted for presentation at the 8th Geography of Innovation Conference, 2025

Abstract

We study how science–industry collaborations foster technological novelty at the inventor level. Using French patent data (1976–2013), we measure recombinant novelty as the creation of new IPC-class combinations and estimate causal effects through a dynamic difference-in-differences design. A first co-invention with a scientific partner substantially raises the probability of recombinant novelty, especially immediately after collaboration, consistent with tacit knowledge transfer through learning-by-doing. Network embeddedness conditions this effect: clustered and constrained positions dampen novelty, whereas more open networks enhance it. Geographical proximity plays a weaker role, with collaborations at distance generating comparable outcomes. Finally, technological context matters: inventors embedded in environments with higher revealed technological advantage display stronger and more persistent gains from collaboration. These findings highlight the catalytic role of science–industry partnerships in opening new technological trajectories, while showing that their impact depends less on geography than on inventors’ network structure and the absorptive capacity of their technological environment.

From angel investors to venture capital: fundraising pathways in professional esports teams

Florian Lefebvre, Pedro Almeida Couto, Nicolas Scelles, Axel Bérard and Si Hao Li

News Conditionally accepted at Venture Capital, 2025

Abstract

Professional esports teams increasingly rely on venture capital (VC) to fund their growth. However, the structural dynamics of this financing model and its financial viability remain underexplored. Anchored in signaling theory, this qualitative study based on seven interviews with esports team representatives and esports investors investigates the structuration of fundraising deals within professional esports teams, analyzing its stages and allocation of funds. It highlights that VC funding is often preceded by early-stage financing, such as business angels and Series A or B rounds, serving as legitimacy signals and used as a cyclical resource for specific projects like international expansion or player acquisitions. Interviews with team executives indicate that fundraising is critical for survival and project acceleration but does not lead to a viable income stream. Challenges include esports' fluctuating market appeal, limited investor understanding of the industry, and difficulties in monetization. However, emerging opportunities lie in leveraging fan communities, exploring cryptocurrency integration, and artificial intelligence applications. The findings deepen the understanding of VC structuration in esports, identifying adaptability and balancing current growth with financial viability as key success factors. Offering practical insights, this study underscores the need for innovative, viable business models to navigate the complexities of the esports ecosystem.

Fast Estimation of BLP Demand with Automatic Differentiation

Si Hao Li

Working Paper 2025

Abstract

The Berry, Levinsohn, and Pakes (1995) model is a workhorse of empirical industrial organization, but GMM estimation is often bottlenecked by repeated share evaluation and fixed-point inversion on CPUs. We implement the demand-side BLP pipeline in JAX to exploit GPU execution with just-in-time compilation and automatic differentiation. On PyBLP-simulated benchmark economies, our implementation reproduces PyBLP estimates on identical markets and delivers large speedups in share computation that grow with the number of simulation draws, products, and markets.

What are economists telling us in the top 5? A Structural Topic Models approach

Si Hao Li

Working Paper 2025

Abstract

This article examines the evolution of research topics published in top five economics journals using advanced textual analysis methods. We implemented Structural Topic Model (Roberts et al., 2014) on our database of articles from the top five journals, which we constructed using web scraping techniques from the RePEc platform. Our findings indicate that economics has evolved, with an increasing resurgence of empirical methods and a significant decline in theory, particularly in general equilibrium.

Work in Progress

Second-Degree Price Discrimination in Digital Goods: Grey Markets and Conflict

Si Hao Li, Martin Delville

Work in progress, 2025

Mobile Money, Interoperability and Competition

Marc Bourreau, Lukasz Grzybowski, Si Hao Li

Work in progress, 2025

Master Thesis

Innovation under Interoperability: An Analysis of Asymmetric Ad-Financed Platforms

Supervised by Marc Bourreau

Abstract

This exercise proposes a theoretical model inspired by and extending the recent approach of Bourreau et al. (2023), to analyze the effect of interoperability on innovation incentives in an asymmetric market of advertising-funded digital platforms (such as WhatsApp vs. Signal). Within a classic Hotelling framework with endogenous multi-homing, we explicitly incorporate strategic innovation choices in the presence of technological spillovers, allowing the dominant platform to copy the innovations developed by the minority platform. Our results show that the introduction or increase of interoperability reduces users' propensity to multi-home, thereby incentivizing the minority platform to intensify its investment in innovation to preserve its vertical differentiation. Conversely, the spillover discourages autonomous innovation by the leader. These theoretical results highlight the necessity of fine-tuned regulation of interoperability levels and the protection of innovations to effectively promote innovation dynamics.

Network externalities, Compatibility, and R&D: A Literature Review

Supervised by Marc Bourreau

Abstract

This literature review aims to provide a synthesis of key themes in Industrial Organization, with a particular focus on markets characterized by network externalities. First, it explores the relationship between competition and innovation before examining the issue of compatibility and its implications, notably in the context of the Digital Markets Act.

Other Publications