Research

• Vertical Integration and Market Structure: Evidence from Tesla's Charging Network (JMP)

 slides  paper  Matlab code (structural)   Matlab code (regression)

Abstract:  This paper studies how vertical integration into charging infrastructure affects price competition, investment, and entry in the electric vehicle (EV) market. Vertical exclusivity increases a firm's market power and restricts charging access for rival producers. At the same time, it strengthens investment incentives in complementary infrastructure, thereby expanding overall EV demand. This market expansion erodes incumbents' ICE profit base, reducing cannibalization concerns and potentially inducing entry by internal combustion engine manufacturers despite an initial competitive disadvantage. Counterfactual simulations removing exclusivity lower prices and improve access for non-Tesla consumers, but weaken investment incentives and reduce total market expansion. Overall, the results highlight a central trade-off between static competition and dynamic coordination: while open access improves allocative efficiency, exclusivity can promote investment and entry in emerging markets with strong demand-side complementarities.

• Estimating Cross-market Interactions in Demand 

 slides  paper  slides (old)  Matlab code  Stata code

Abstract:  Discrete choice models are widely used to estimate demand in differentiated product markets, and a growing literature extends this framework to study cross-market interactions. In many applications, product market shares are observed at an aggregate level while interacting variables vary locally, creating an aggregation mismatch that complicates identification and raises endogeneity concerns. I develop a two-level inversion approach that jointly inverts aggregate product-level shares and local group-level shares, leveraging the insight that cross market interactions operate at the level of product groups. This procedure recovers location specific unobserved demand and enables instrumental variables estimation without requiring highly disaggregated product-level data. I apply the method to the UK electric vehicle market from 2014 to 2023, where model level shares are national but charging infrastructure varies across local authorities. The results reveal positive but heterogeneous complementarities between electric vehicles and charging station and show that failing to instrument leads to substantially biased estimates. 

• The Evolution of Aggregate Markups, with Steve Bond 

Abstract:  Is there evidence of rising markups across countries? In this paper, we implement a new method that leverages the relationship between output returns to scale, revenue returns to scale, and firms’ profit-maximizing behavior. We compute upper and lower bounds for revenue elasticities using the sales-weighted arithmetic, geometric, and harmonic means of observed revenue shares. Applying this framework, we obtain semi-parametric bounds for aggregate markups for G7 countries, excluding the United States, under the assumption of constant returns to scale in production technology. Our findings suggest that the increase in aggregate markups is considerably more modest than previously reported and is accompanied by a slight rise in markup dispersion. We also implement a hybrid markup estimation approach, which further supports the conclusion that aggregate markups have risen only modestly, or not at all, across our sample of countries.