Working papers

Innovation Networks and Business-Stealing. (2023). CEPR Discussion Paper DP17911. With Philippe Aghion, Matthew O. Jackson and Antoine Mayerowitz.

Abstract. We use the universe of US Patent and Trademark Office (USPTO) data on patents and inventors from 1976 to 2017 to look at how inventors’ potential concern for business-stealing affects coauthorship on patents. First, we find an inverted-U shape in the fraction of coauthors that an inventor has per year who are new as a function number of other inventors also working in an inventor's field. Second, we find that after a breakthrough invention, an inventor brings in persistently fewer than usual new coauthors. Third, a higher potential concern for business stealing—as measured either by the number of others working or the average price markups by firms in the area—leads to a higher drop in the fraction of new co-authors per patent after a breakthrough. We show how these patterns can be explained via a simple model in which inventors trade off gains from collaboration against threats of business stealing.

Abstract. Does the financial market price knowledge spillovers? We find evidence that patent grants impact stock returns of firms linked by technological knowledge dependencies. By tracking directed patent citations among publicly listed companies, we create a measure of each firm's daily exposure to new patents granted to its technologically upstream firms (neighborhood). Patents granted to a firm’s neighborhood boosts its abnormal returns. These financial spillovers are economically significant, with returns attributable to a firm’s neighborhood increasing during the week of the grant, in contrast with the gradual fade-out of returns attributable to a firm’s own patent grants, suggesting gradual diffusion of information in markets. These effects tend to be localized within a firm’s immediate connections. Further, we provide a novel decomposition of financial spillovers emerging from product market rivals and suppliers against knowledge spillovers. We argue that patent citations capture important business ties priced by the market not fully captured by product market relationships.

Foreign competition and R&D specialization. With Antoine Mayerowitz.

Abstract. We examine the impact of the surge in Chinese patenting in the US on the specialization and quality of innovation produced by US firms. Using the rise in Chinese patents filed in the USPTO since the 2000s across various technologies, and leveraging the variation in firms' exposure to these technologies through a shift-share IV design, we demonstrate that the firms most affected by Chinese competition experience an increase in their R&D specialization through a reduction in the number of R&D lines of firms, the scope of patents and the originality of their innovations. We further document that exposure to foreign competition is also associated with a decline in broad measures of patent quality, despite an increase in the number of patents filed by the affected firms. We suggest that these results are consistent with a basic model where firms trade-off research effort on originality with producing more specialized and incremental innovations. Our findings shed light on new potential explanations behind the documented growth in specialization and decline in R&D quality in recent decades.


Innovation Networks and Business-Stealing. (2023). The Economics of Creative Destruction. Ed. Ufuk Akcigit and John van Reenen. Harvard University Press. With Matthew O. Jackson and Antoine Mayerowitz.

Case studies

Analytical Tools in Private Equity: Return Bridge. (2019). Harvard Business School Background Note 220-119. With Victoria Ivashina.

Clayton, Dubilier & Rice at 40. (2018). Harvard Business School Case 819-055. With Josh Lerner and Terrence Shu.

Valuation Techniques in Private Equity: LBO Model. (2018). Harvard Business School Background Note 218-106. With Victoria Ivashina and Alexey Tuzikov.

Works in progress

Perceptions of innovation. With Xavier Jaravel and Josh Lerner.

Heterogeneous technological change.

A century of unequal opportunity in India.