@techreport{NBERw11201,
 title = "Competition and Efficiency in Congested Markets",
 author = "Daron Acemoglu and Asuman Ozdaglar",
 institution = "National Bureau of Economic Research",
 type = "Working Paper",
 series = "Working Paper Series",
 number = "11201",
 year = "2005",
 month = "March",
 URL = "http://www.nber.org/papers/w11201",
 abstract = {We study the efficiency of oligopoly equilibria in congested markets. The motivating examples are the allocation of network flows in a communication network or of traffic in a transportation network. We show that increasing competition among oligopolists can reduce efficiency, measured as the difference between users' willingness to pay and delay costs. We characterize a tight bound of 5/6 on efficiency in pure strategy equilibria. This bound is tight even when the number of routes and oligopolists is arbitrarily large. We also study the efficiency properties of mixed strategy equilibria.},
}