Essays on competition, cooperation, and market structures

My dissertation examines competition, cooperation, and efficiency in three market settings in which a population of economic agents interact, either directly with each other in pairwise matches, directly with firms, or with firms via a platform. In one chapter I consider a population of customers who have different valuations for a good sold by competing merchants, as well as varying preferences over the merchant from which to purchase the good and the payment form with which to make the purchase, and examine what the effects might be if a merchant placed an additional surcharge on transactions completed with a payment form that is more costly for the merchant. The cost for the merchant can vary dramatically depending on the payment form used. For example, a credit card transaction is generally more expensive for the merchant than a debit card transaction, even if the transaction is completed using the same technology and is processed over the same network (e.g., a MasterCard signature debit transaction and a MasterCard credit card transaction). Historically, with limited exceptions, merchants have been prohibited, both by law and by the contract permitting the acceptance of that network's cards, from charging customers different prices for transactions completed using different payment cards, despite the different costs these transactions impose on them. Recent concessions made by several major payment networks in response to legal challenges raises the possibility that this paradigm might change in the future. This chapter examines what the effects might be if merchants were permitted to charge customers different prices based on the payment form and whether these effects depend on differences between the merchants, such as differences in the marginal cost of providing the good. In another chapter, I consider a population of individuals made up of more-patient and less-patient types who interact directly with each other in a repeated prisoner's dilemma embedded in a search model. A player is matched anonymously with another player to play a prisoner's dilemma game repeatedly until the match is ended, either exogenously or endogenously by one of the players, at which point each player may receive another random match. I first determine when it is feasible to achieve the best outcome in which all players cooperate. When it is not possible to achieve full cooperation, I examine how welfare can be improved over the outcome in which no players cooperate. When conditions are such that less-patient players choose not to cooperate, I first examine how separation by action within a single market can increase welfare for all players over the uncooperative equilibrium, with more-patient players choosing to cooperate in hopes of forming a cooperative relationship, despite the risk of being matched with a less-patient player who chooses not to cooperate. I then examine how full separation of the more- and less-patient players, made possible by introduction of a second market, can increase the welfare of the more-patient players without harming the less-patient players. In a third chapter, customers choose to purchase a good from one of several competing firms in a setting in which network congestion and firms' investment in capacity plays an important role in firm costs and product quality, e.g., the wireless industry. Wireless carriers (e.g., Verizon) compete not only on the price of their service but also on its quality. The quality of a carrier's service is determined in part by the quantity of customers it serves and by investment in capacity with which to serve them. While the primary effect of a carrier increasing its capacity is an increase in that carrier's service quality, there are also externality effects on other wireless carriers. For example, if carrier A increases its capacity, thereby increasing its service quality, and causes some customers to leave a competing carrier B, the service quality experienced by customers who remain with carrier B will increase as a result of the decreased congestion in carrier B's network. This chapter examines the interplay between these effects alongside traditional price competition in this oligopoly setting.