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Collusion in auctions and the role of communication to sustain it: a microeconomic approach

October 6, 2014

Editor’s note: This post is part of a series showcasing Barcelona GSE master projects by students in the Class of 2014. The project is a required component of every master program.

Collusion in auctions and the role of communication to sustain it: a microeconomic approach


Giuseppe Leonello

Master Program:

Competition and Market Regulation

Paper Abstract:

Collusion among bidders in auctions is an important topic in competition economics since it decreases the seller’s revenues and the social welfare. In this project the focus will be on the role of communication among bidders for the incentives to collude.

In the literature, communication among bidders has always been treated as an exogenous variable. This assumption will be relaxed and the choice of communicate will be endogenous and function of the expected collusive profits and the expected costs of collusion represented by the risk to be catch and punished.

The auctioneer can monitor the market and the auction process to discover the collusive agreement, exerting a costly effort.

The model will find the minimum level of effort needed to make bidders not having incentives to communicate and collude. However, the auctioneer will exert this level of effort only when the expected gains are higher than expected costs. For this reason, in some case the optimal choice for the auctioneer will be to lead bidders to collude even if this will not maximize the social welfare.

Government interventions to reach the not collusive equilibrium will be discussed. In particular, they will take the form of an increase in the punishment when bidders are discovered to collude and the subsidization of the cost needed to exert the optimal level of effort.


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