Research

Asymmetric Auctions with Discretely Distributed Valuations - (with Nicola Doni and Domenico Menicucci) - B.E. Journal of Theoretical Economics (2025).

We examine a two-bidder auction setting in which the distributions for the bidders’ valuations are asymmetric over a support consisting of three elements. For the first price auction, for each parameter values we derive the unique Bayes Nash Equilibrium in closed form. We rely on this result to compare the revenue in the first price auction with the revenue in the second price auction. The latter is often revenue superior to the former, and we determine precisely, given a distribution for the value of a bidder, when a distribution for the value of the other bidder exists such that the first price auction is superior to the second price auction. 

Collusion with Not-So-Secret Rings  - Journal of Quantitative Economics, 22(2): 563 - 570. (2024).

When collusion is analyzed for Independent private value auctions, it is implicitly assumed that ring presence is commonly known to colluding and non-colluding bidders. We drop this assumption and analyze a simple model of a first price Independent Private Value auction with uniformly distributed values where a single bidder knows privately of the existence of collusion by others. We show that this knowledge leads him to bid shading (weakly) in the first price auction compared to what he would have bid otherwise. This in turn yields the result that the second price auction dominates the first price auction in terms of seller revenue. This contrasts results from the literature showing that under our framework, when bidding is done while the presence of colluding bidders is common knowledge, the first price auction dominates the second price auction. 

Earlier versions appeared under the title - Suspecting Collusion.

Secret vs Public Rings in Common Value Auctions - Revise & Resubmit - International Journal of Economic Theory

In a second-price common value auction with colluding bidders and an "almost all-inclusive ring," we examine whether the auctioneer should reveal the presence of the bidding ring. Specifically, we consider whether this revelation should be public or private to the non-ring bidder. We show that publicly revealing the ring’s presence induces the non-ring bidder to bid higher than in a non-cooperative scenario. This suggests that the auctioneer may benefit from public disclosure of the ring. Additionally, it highlights a potential tactic for the auctioneer to manipulate the auction by creating the false impression of collusion to drive higher bids.

Fleets, Congestion and Consumer Choice in Urban Transport - (with Federico Boffa and Alberto Iozzi)

We consider an environment in which heterogenous users may choose between private vehicles, vehicles belonging to a fleet, and public transport. Our model reproduces empirical evidence, with users’ choices associated to their value of time. Public transport is used by users with low value of time, private cars by users with intermediate value of time, and fleets vehicles by users with high value of time.

We look at the effects of the market structure of the fleet on welfare, and show it depends on the cost of owning a private car: when the cost of private car is low, then a competitive fleet is welfare superior to a monopolistic fleet, because welfare in that case requires prices to reflect costs, something competition is better able at achieving than monopoly. When the cost of private car is instead high, then a monopolistic fleet is welfare superior to a competitive fleet, as the monopolistic fleet has an incentive to internalize network externalities, which is what matters in those cases. We then study taxation schemes to reproduce first best in this environment. When r is low, then there is a classic problem of monoopoly in the absence of network externalities. The optimal tax then requires to subsidize the monopolist, so as to induce it to reduce prices at the level of marginal costs. Instead, when r is high, a tax, similar to a congestion charge, should be levied on the competitive fleet to restore social optimality.

On the Asymmetric Punishment of Harassment Bribes

Food Fraud for Horizontally Differentiated Products

Competing with Self-Providing Consumers