Contract theory claims that renegotiation prevents attainment of the efficient solution that could be obtained under full commitment. Assessing the cost of renegotiation remains an open issue from an empirical viewpoint. We fit a structural principal-agent model with renegotiation on a set of contracts for urban transport services. The model captures two important features of the industry as only two types of contracts are used (fixed price and cost-plus) and subsidies are greater following a cost-plus contract than following a fixed-price one. We conclude that the welfare gains from improving commitment would be significant but would accrue mostly to operators. (JEL D82, D86, L51, L92, R42, R48)

We develop a model of competition in prices and infrastructure among mobile network operators. Although consolidation increases market power, it can lead to more efficient data transmission due to economies of scale, which we derive from physical principles. After estimating our model with French consumer and infrastructure data, equilibrium simulations reveal that while prices decrease with the number of firms, so do download speeds. Our framework also allows us to quantify the impact of spectrum allocation. The marginal social value of spectrum exceeds firms’ willingness to pay in our model as well as observed prices in spectrum auctions.