A indústria de cartões de pagamento é definida pela literatura acadêmica como um mercado de dois lados. Um dos lados é o mercado de emissão, que realiza a comercialização de cartões para os portadores. O outro lado é o mercado de credenciamento, que efetua a afiliação de estabelecimentos comerciais para que estes aceitem pagamentos com cartões. O foco deste trabalho é o mercado de credenciamento no Brasil. O objetivo do estudo foi analisar a concentração do mercado brasileiro de credenciamento no período entre 2010, quando houve o início da intervenção governamental na indústria de cartões, e 2016. Com a imposição do fim do monopólio no credenciamento das principais marcas mundiais, Visa e Mastercard, os órgãos reguladores buscavam estimular a entrada de novos concorrentes, a fim de obter uma melhor eficiência econômica e maior bem-estar social. Os resultados deste trabalho evidenciaram redução na concentração do mercado com a entrada de novos concorrentes, embora os índices permaneçam elevados. O trabalho buscou analisar, também, a variação das taxas cobradas dos estabelecimentos comerciais neste período. Neste aspecto, os resultados mostram que as taxas médias anunciadas pelas credenciadoras, cobradas normalmente de pequenos estabelecimentos, aumentaram para as transações de débito, ao contrário do que se esperava para um mercado com mais concorrentes, e se mantiveram estáveis para transações de crédito. As elevadas taxas de intercâmbio, a falta de interoperabilidade dos sistemas de captura das transações e a continuidade de contratos de exclusividade para aceitação de cartões entre emissores e credenciadores representaram dificuldades para que os objetivos dos órgãos reguladores fossem plenamente alcançados no período analisado. / The payment cards industry is a two-sided market, as defined by the academic literature. In one side there is the card issuing market that accomplishes the commercialization of cards for the cardholders. The other side is the acquiring market that makes the affiliation of merchants to accept payments with cards. The focus of this work is the acquiring market in Brazil. The objective of the study is to analyze the concentration of the Brazilian acquiring market in the period between 2010, when there was the beginning of the government intervention in the card industry, to 2016. With the mandate to end the acquiring monopoly of the main world brands, Visa and Mastercard, the regulatory agencies sought to stimulate the entrance of new competitors, in order to obtain a better economic efficiency and greater social welfare. The study results showed a reduction in market concentration with the entry of new competitors, although the concentration remains high. The work also aimed to analyze the variation of prices charged to merchants in this period. In this respect, the results show that the average rates announced by the acquirers, applied normally to small businesses, increased for debit transactions, contrary to what was expected for a market with more competitors and remained stable for credit transactions. The high interchange rates, the lack of interoperability of transaction capture systems and the continuation of exclusivity agreements for the acceptance of cards between issuers and acquirers represented difficul,ties for the objectives of the regulatory bodies to be fully achieved in the period under review.

A indústria de cartões de pagamento é definida pela literatura acadêmica como um mercado de dois lados. Um dos lados é o mercado de emissão, que realiza a comercialização de cartões para os portadores. O outro lado é o mercado de credenciamento, que efetua a afiliação de estabelecimentos comerciais para que estes aceitem pagamentos com cartões. O foco deste trabalho é o mercado de credenciamento no Brasil. O objetivo do estudo foi analisar a concentração do mercado brasileiro de credenciamento no período entre 2010, quando houve o início da intervenção governamental na indústria de cartões, e 2016. Com a imposição do fim do monopólio no credenciamento das principais marcas mundiais, Visa e Mastercard, os órgãos reguladores buscavam estimular a entrada de novos concorrentes, a fim de obter uma melhor eficiência econômica e maior bem-estar social. Os resultados deste trabalho evidenciaram redução na concentração do mercado com a entrada de novos concorrentes, embora os índices permaneçam elevados. O trabalho buscou analisar, também, a variação das taxas cobradas dos estabelecimentos comerciais neste período. Neste aspecto, os resultados mostram que as taxas médias anunciadas pelas credenciadoras, cobradas normalmente de pequenos estabelecimentos, aumentaram para as transações de débito, ao contrário do que se esperava para um mercado com mais concorrentes, e se mantiveram estáveis para transações de crédito. As elevadas taxas de intercâmbio, a falta de interoperabilidade dos sistemas de captura das transações e a continuidade de contratos de exclusividade para aceitação de cartões entre emissores e credenciadores representaram dificuldades para que os objetivos dos órgãos reguladores fossem plenamente alcançados no período analisado. / The payment cards industry is a two-sided market, as defined by the academic literature. In one side there is the card issuing market that accomplishes the commercialization of cards for the cardholders. The other side is the acquiring market that makes the affiliation of merchants to accept payments with cards. The focus of this work is the acquiring market in Brazil. The objective of the study is to analyze the concentration of the Brazilian acquiring market in the period between 2010, when there was the beginning of the government intervention in the card industry, to 2016. With the mandate to end the acquiring monopoly of the main world brands, Visa and Mastercard, the regulatory agencies sought to stimulate the entrance of new competitors, in order to obtain a better economic efficiency and greater social welfare. The study results showed a reduction in market concentration with the entry of new competitors, although the concentration remains high. The work also aimed to analyze the variation of prices charged to merchants in this period. In this respect, the results show that the average rates announced by the acquirers, applied normally to small businesses, increased for debit transactions, contrary to what was expected for a market with more competitors and remained stable for credit transactions. The high interchange rates, the lack of interoperability of transaction capture systems and the continuation of exclusivity agreements for the acceptance of cards between issuers and acquirers represented difficul,ties for the objectives of the regulatory bodies to be fully achieved in the period under review.

This dissertation comprises three essays on theoretical analysis of middlemen in intermediated markets. Chapter 1 gives a brief survey on the market intermediation literature and also briefly describes the subsequent chapters. In Chapter 2 I study the role of horizontally differentiated middlemen in a bilateral search market in which heterogeneous agents of each group possess private information concerning the value of joint production. I focus on the effect of the middlemen on agents' search efforts and on pricing decisions by middlemen. In particular, I show that the middlemen intensify agents' search activities. I also provide an explanation for why middlemen often use asymmetric pricing for two groups in a market. In Chapter 3 I study a model of platform competition when both indirect network effect and the desirability concerns of the agents are present. The desirability concerns are defined as the perceived quality of platforms. A platform with a higher proportion of high-type agents is regarded as a platform with a better quality. Under these circumstances, I derive conditions for the existence of equilibrium. In a dominant platform equilibrium, I show that some agents may not be served by the dominant platform. I also show that two platforms with different perceived quality may coexist in equilibrium. It suggests that endogenous market segmentation may arise in two-sided markets. In chapter 4 I study the effort-maximizing contest rule when there is a positive externality between aggregate efforts and the contest audience: the audience is more willing to pay for watching a contest if each participating contestant expends more effort. The Tullock rent-seeking contest with endogenous entry is extended by incorporating the contest audience into the model. In order to fund the contest, the organizer with no budget has to collect fees from one or both of two groups. It is shown that the effort-maximizing contest rule under a positive externality attracts only two entrants and, in the unique subgame perfect equilibrium, the entrants are always subsidized regardless of the size of entry costs, and the audience pay a positive fee. / Ph. D.

The hospitality industry is characterized by a close interdependence between retailers and suppliers. Retailers depend on suppliers to provide the necessary goods and services to operate effectively, while suppliers rely on retailers to buy and market their products. With intense competition in the industry, effective supplier selection has become a critical asset for companies. Traditional supply chain management approaches that focus solely on increasing economic value are insufficient in the face of growing pressure for socially and environmentally responsible business practices. As a result, new criteria, including environmental, social, political, and customer satisfaction considerations, have been added to the pre-existing factors in supplier selection. While restaurants strive to select suppliers who meet their quality, social, and environmental standards, these suppliers may still face internal issues such as food safety, ethical malpractice, environmental concerns, and human rights issues. When such issues arise, it is unclear whether customers hold restaurants accountable for the mistakes of their suppliers, even when the restaurant has not been directly involved in these issues. The first part of this dissertation aims to explore how consumers associate negative news about supplier food quality and practices with the restaurants they patronize. By doing so, this study contributes to a better understanding of the indirect link between supplier issues and restaurant market value. On another note, Online Travel Agents (OTAs) play an important intermediary role in the two-sided travel distribution market. A critical factor that enhances a firm's competitive advantage is innovation. Yet, the analysis of innovation in the OTA context is scarce. The main objective of the second part of this dissertation is to fill this gap and examine the effect of OTA innovations on firm performance. We analyze the effect of two-sided market specific innovations (same-side and cross-side) on performance and contribute to the literature by expanding the theoretical understanding of innovations. We find that producer-to-consumer innovations have a greater effect on OTA performance than producer-to-producer and consumer-to-consumer innovations. A fundamental managerial implication is that exchange management is an area to be enhanced when innovating in travel market distribution. Lastly, with the unprecedented increase in food delivery demand due to the new consumption habits of individuals, delivery pricing is an issue to consider keeping consumers happy and continuously demanding this service. Research in economics and in service marketing have described how consumers do recognize the "free" under a product's price differently. This pricing approach is based upon that widespread notion that providing free goods or services to customers adds value to them and so increases their desire to buy. In the last part of the dissertation, we study the Zero price model on a multicomponent product with Food being the first component (where its price is always positive) and the delivery service as the second (where its price will eventually hit the zero-price tag). Elaborating more on previous studies and filling their gaps, we will be dividing the zero-price model into three scenarios: The true free scenario, the true free scenario with different discounts, and the fake-free scenario as each one is expected to yield different consumer behaviors in the process, but all should act similarly when the price hits the "free" tag. / Doctor of Philosophy / The hospitality industry is deeply intertwined, as retailers and suppliers rely on one another for success. Retailers depend on suppliers for essential goods and services, while suppliers count on retailers for purchasing and promoting their products. With increasing competition, it is vital for companies to select the right suppliers. Merely focusing on profit maximization is no longer sufficient, as there is growing pressure to adopt socially and environmentally responsible practices. Factors such as environmental, social, political aspects, and customer satisfaction now play a role in supplier selection. Restaurants strive to collaborate with suppliers that meet their criteria, but these suppliers may still encounter issues like food safety, ethical dilemmas, environmental issues, and human rights problems. The question remains whether customers hold restaurants accountable for their suppliers' mistakes. The first part of this dissertation investigates consumer responses to negative supplier news and its impact on their choice of restaurants. In another aspect, Online Travel Agents (OTAs) significantly influence the travel market. Innovation is a critical factor in achieving success, yet there has been limited research on innovation within the OTA context. The second part of this dissertation seeks to bridge this gap by examining how OTA innovations affect their performance. The study reveals that certain innovations have a more significant impact on OTA performance than others, indicating that enhancing exchange management is essential for innovation within the travel market. Lastly, the surge in food delivery demand has made delivery pricing a crucial aspect in maintaining customer satisfaction and promoting continued use of the service. Research indicates that consumers perceive "free" items or services distinctively, with "free" offers increasing their inclination to purchase. The last part of this dissertation explores the Zero price model for food delivery, wherein the food is the first component with a positive price, and the delivery service is the second component with a potentially free price. We categorize the zero-price model into three scenarios: true free, true free with different discounts, and fake-free, anticipating that they will result in different consumer behaviors, but all should exhibit similar effects when the price is "free."

Les plateformes de financement participatif (« crowdfunding ») permettent auxentrepreneurs de faire financer leurs idées en contactant directement de petits investisseurset des consommateurs potentiels. Cette thèse porte sur le fonctionnement de cesplateformes d’un point de vue économique, en particulier, sur les stratégies mises en placepar les plateformes et les entrepreneurs dans ce marché. Cette thèse est organisée en deuxparties. La première partie se focalise sur le marché du financement participatif et lesstratégies de compétition des plateformes. La deuxième partie se consacre aux incitationsdes entrepreneurs et les potentielles barrières à son entrée – et donc au développement dece marché. Tout d’abord, nous discutons la caractéristique des plateformes de financementparticipatif d’après la théorie des marchés « bifaces ». Nous soulignons le rôle decoordination de ces plateformes à partir de différentes structures de prix et de règlesspécifiques qui régulent la participation d’entrepreneurs et d’investisseurs. Nous soulignonsl’état de l’art de la littérature existante pour comprendre les incitations des entrepreneurs etdes investisseurs de participer à ces plateformes, les outils mises en place pour réduire lesasymétries d’information, et les biais des investisseurs par rapport aux caractéristiquesphysiques des entrepreneurs. Le deuxième article étudie le défi des plateformes bifacesd’équilibrer « quantité » et « qualité » des agents des deux côtés et en même temps tenir encompte la compétition. Nous étudions en particulier comment une stratégie d’attirerd’avantage d’entrepreneurs d’un côté peut réduire la qualité de l’expérience des usagers. Letroisième article est consacré à démontrer empiriquement la valeur informationnelle dufinancement participatif pour les entrepreneurs. Avant le lancement d’un nouveau produitsur un marché, les entrepreneurs font face à des fortes incertitudes qui peuvent être paillésavec le « feedback » reçu des campagnes du financement participatif, ce qui constitue uneincitation de plus pour participer à ces marchés. Le quatrième et dernier article présente uncontrepoint de ces incitations, et interroge les barrières à l’entrée sur ces marchés. Enparticulier nous étudions les barrières en termes de temps qui doit être consacré à unecampagne de financement participatif et qui peut décourager une partie des entrepreneursde chercher cette alternative. Pour conclure, nous discutons de l’implication de nosrésultats. / Crowdfunding platforms allow entrepreneurs to directly contact small investorsand potential consumers to help them finance their ideas. This thesis dedicates tounderstanding the dynamics of these platforms from an economic perspective. We areparticularly interested in comprehending the entrepreneurs’ and platforms’ strategies in thismarket. This thesis is composed by four scientific articles organized in two parts. The firstpart focuses on analyzing the crowdfunding market dynamics and the design and strategiesof crowdfunding platforms. In the first article (Chapter 1), we discuss the characteristic ofcrowdfunding platforms based on the theory of two-sided markets. We underline thestrategies platforms use to perform their coordinating role of the market. Based on thecurrent literature, we analyze the incentives and disincentives of entrepreneurs andinvestors to participate on these platforms as well as the instruments to reduce informationasymmetries and the potential biases on the investors’ screening process in relationship toentrepreneurs’ physical characteristics. The second article (Chapter 2) examines thechallenge of crowdfunding platforms to balance “quantity” and “quality” on both sides ofthe market, and at the same time accounting for competition. In particular, we examinehow a strategy to attract more entrepreneurs to one side can reduce platforms’ thecompetitive advantage and potentially deteriorate users’ experience. The second part of thethesis is devoted to the incentives and disincentives for entrepreneurs to join crowdfundingplatforms. In the first article of the second part (Chapter 3 of this thesis), we empiricallydemonstrate the informational value of crowdfunding for entrepreneurs. Before launchinga new product in a market, entrepreneurs face high uncertainties that can be reduced withthe “feedback” received from crowdfunding campaigns. Therefore, the informational valueof crowdfunding serves as an additional incentive to entrepreneurs besides obtainingfinancial support for their ideas. The fourth and last article aims at pointing outdisincentives to join platforms, in particular how the need of allocating scarce time andattention to campaigns may discourage some entrepreneurs from seeking this alternative.To conclude, we summarize the implications of the main findings and suggest avenues forfuture research

Apresentamos três estudos sobre os assuntos mencionados no título. O primeiro, econométrico, avalia os impactos da quebra de exclusividade no lado credenciador da indústria de cartões de pagamentos no Brasil que ocorreu em 2010. Por um lado, tentamos a construção de um grupo de controle e, por outro, fazemos a decomposição dos preços em markup e custo marginal. As estimações, que empregam um banco de dados com informações individuais para os maiores lojistas de cada setor, apontam para o sucesso dessa intervenção na promoção da concorrência. No segundo artigo, propomos que cobranças indevidas feitas por instituições financeiras podem ser uma forma de discriminação de preços, já que sua devolução demanda esforço dos consumidores. Nesse caso, tendo em vista que as cobranças indevidas ótimas dependem do perfil do consumidor, construímos um teste baseado numa função de verossimilhança para mostrar como a informação de reclamações poderia ser utilizada para detectar esse tipo de comportamento, mesmo quando a autoridade interessada nesse monitoramento sabe menos sobre os clientes que a instituição financeira. O terceiro artigo, teórico aplicado, estuda o comportamento de plataformas comerciais em mercados de dois lados nos quais os papéis de compradores e vendedores são bem definidos e há heterogeneidade dentro de cada um desses grupos de agentes. Diferentemente do que ocorre no caso em que os interesses são simétricos, no lado vendedor não ocorre autosseleção dos participantes e a plataforma passa a ter um papel de certificação dos vendedores, criando ambientes de qualidade selecionada onde um preço maior pode ser cobrado dos compradores. / This thesis has three papers related to the subject in the title. The first one, an econometric paper, evaluates the impact of a break of exclusivity promoted by Brazilian authorities in the payment card acquiring industry in 2010. We use two frameworks: in one of them, we try to identify categories of merchants to use as control group, while in the other we decompose prices into markup and marginal cost elements. The estimations employ a dataset of individual merchants with information for the largest ones in each category. The results indicate success in promoting some competition. In the second paper, we argue that undue charges made by financial institutions may be a form of price discrimination, since their reversion requires effort from consumers. Given that in such case the optimal undue charges depend on consumers profiles, we build a likelihood function based test to show how information on complaints might be used to detect this sort of behavior, even when the relevant authority knows less about clients than the financial institution. The third one, an applied theoretical paper, analyses the behavior of commercial platforms in two-sided markets where the roles of buyers and sellers are well defined and there is heterogeneity within each of these groups of agents. Differently from what happens in a setting with symmetric interests, in the seller side no self-selection takes place and the platform gains an important quality certification role, creating spaces for trade where seller quality is higher and buyers are willing to pay more.

Digital games are part of the creative industries, which is based on value creation through ideas and creativity. This market has gained relevance due to technology development that attracted both new firms and users. The present dissertation aims to explore three themes: (1) video game market as a two-sided market; (2) the effects of characteristics and behavior of game titles on consoles sales; and (3) project management to develop digital games. Those themes were explored through three articles: the first is a literature review and a bibliometric study of the economic concepts on two-sided market, which focused at identifying main topics, research trends and avenues for futures research. The second text is an analysis on the simultaneous influence of games\' quality and exclusivity on console sales. The last one is a qualitative, multiple-case study to understand, explore and suggest improvements to game project management in the Brazilian market. Findings include: (1) the main authors and topics, trends and developments, from and avenues for future research; (2) combinations of quality and exclusivity can affect console sales either positively or negatively, (3) quality has a predominant effect on sales over games non-exclusivity; and (4) the use of agile methodologies and Design Thinking are diffused among game developers. / Sem resumo.

Diese Dissertation besteht aus drei Aufsätzen, in denen verschiedene Aspekte von zweiseitigen Märkten untersucht werden. Dabei handelt es sich um Märkte mit zwei verschiedenen Nutzergruppen, von denen jede Netzwerkeffekte auf die jeweils andere Seite ausübt. Im ersten Aufsatz werden die Wechselwirkungen zwischen den traditionellen (offline) Nachfragekanälen und den neuen (online) Nachfragekanälen in der deutschen Zeitschriftenindustrie analysiert. Dabei liegt der Fokus insbesondere auf den Effekten zwischen Offlinewerbung und Onlinewerbung. Das Ergebnis der Schätzung eines dafür entwickelten ökonomischen Modells ist, dass Offline- und Onlinewerbung moderate Substitute füreinander sind. Dies erklärt die Verlagerung von Offline- zu Onlinewerbung, die man in den vergangen Jahren beobachten konnte. Im zweiten Aufsatz wird ein semistruktureller Ansatz zur Messung von Netzwerk-Effekten auf potentiell zweiseitigen Monopol-Plattformen entwickelt. Der Test ist hinreichend, wenn lediglich Daten zum Gesamtumsatz der Plattform zur Verfügung stehen. Sind getrennte Umsatzdaten für die beiden Seiten verfügbar, dann ist der Test sowohl notwendig als auch hinreichend. Der dritte Aufsatz untersucht Mechanismen und Anreize, die die Koordination von Angebot und Nachfrage auf Kreditmärkten ermöglichen, in denen es keine Finanzintermediäre mit eigener finanzieller Beteiligung an den vergebenen Darlehen gibt. Dazu wird der Online-Direktkreditmarkt analysiert, in welchem an die Stelle von klassischen Finanzintermediären ein System von Gruppen tritt. Anhand eines Differenz-in-Differenzen-Ansatzes wird gezeigt, dass Entgelte für die Leiter dieser Gruppen zu adversen Anreizen führen können. Nach Abschaffung der Entgelte differenzieren die Leiter der Gruppen deutlich stärker bei der Auswahl derjenigen Kreditgesuche, die sie als investitionswürdig empfehlen. Gleiches ist zu beobachten, wenn die Leiter der Gruppen selbst zu einem großen Teil an den entsprechenden Darlehen beteiligt sind. / This dissertation investigates various aspects of two-sided markets - markets with at least two distinct user groups each of which exerts inter-group network effects on the other side - in the online world. In the first paper, I examine the interactions between the traditional (offline) demand channels and the new (online) demand channels in the German magazines industry, focusing in particular on the link between offline and online advertising. I find that offline and online advertising are substitutes although not perfect ones. This explains the shift from offline to online advertising observed in recent years. In the second paper, I develop a semi-structural approach to identify network effects on two-sided monopoly platforms without data on prices and quantities. A sufficient test for the existence of network effects is derived when only data on total revenue is available. If separate revenue data is available on the two sides, then the test is both necessary and sufficient. The third paper investigates the certification mechanisms and incentives that enable lending markets to match demand and supply despite the absence of financial intermediaries with skin in the game. The institutional setting for this analysis is the online social lending market, in which potential lenders and borrowers interact directly without a financial intermediary but can create self-organized groups instead. A difference-in-difference approach is used to examine how the same groups behave before and after the exogenously imposed elimination of rewards for the leaders of these groups. Allowing group leader rewards is found to be detrimental for the market outcome. Group leaders become more careful in screening after the elimination of these rewards, and if their loan participation is high, i.e. when they have skin in the game and are thus severely hurt by a borrower default.

This dissertation studies strategies to mitigate the risks associated with operational and strategic decisions of a firm, particularly focusing on project management, product development and procurement decisions. In the first essay we develop two simulation-based methods to evaluate risky capital investment projects that involve managerial flexibility. Many risky projects are characterized by significant demand and operational risks (such as learning curve uncertainty) that are difficult to capture by simple stochastic processes. We propose using system dynamics simulations to estimate the cash flow resulting from these projects and build upon prior work on real options valuation in the decision analysis literature to develop two valuation algorithms. In the second essay we explore the technology investment decisions for platforms in markets that exhibit cross-network effects. We focus on the trade-off firms must make between investing new product development resources to increase a platform's core performance and functionality versus investments designed to leverage the platform's cross-network effects. Abstracting from examples drawn from multiple industries, we use a strategic model to gain intuition about how to make such trade-off decisions under competition. In the third essay, we analyze the optimal procurement strategy of a firm that faces supply and demand risk. In particular, the firm can source from two unreliable suppliers with different delivery characteristics. We study the optimal order allocation policy shaped by the trade-offs between delivery leadtime, reliability and procurement cost. Further, we discuss the value of leadtime flexibility in supply risk mitigation and highlight the role of an inferior supplier in a firm's multi-sourcing strategy. The main contribution of this dissertation to the operations management literature is two-fold. First, it illustrates the role of effective risk mitigation through operational strategies of leadtime flexibility and supply diversification as well as through recognizing managerial flexibility. Second, it highlights the importance of leveraging third-party content development while making technology investment decisions for platforms in two-sided markets. / text

Apresentamos três estudos sobre os assuntos mencionados no título. O primeiro, econométrico, avalia os impactos da quebra de exclusividade no lado credenciador da indústria de cartões de pagamentos no Brasil que ocorreu em 2010. Por um lado, tentamos a construção de um grupo de controle e, por outro, fazemos a decomposição dos preços em markup e custo marginal. As estimações, que empregam um banco de dados com informações individuais para os maiores lojistas de cada setor, apontam para o sucesso dessa intervenção na promoção da concorrência. No segundo artigo, propomos que cobranças indevidas feitas por instituições financeiras podem ser uma forma de discriminação de preços, já que sua devolução demanda esforço dos consumidores. Nesse caso, tendo em vista que as cobranças indevidas ótimas dependem do perfil do consumidor, construímos um teste baseado numa função de verossimilhança para mostrar como a informação de reclamações poderia ser utilizada para detectar esse tipo de comportamento, mesmo quando a autoridade interessada nesse monitoramento sabe menos sobre os clientes que a instituição financeira. O terceiro artigo, teórico aplicado, estuda o comportamento de plataformas comerciais em mercados de dois lados nos quais os papéis de compradores e vendedores são bem definidos e há heterogeneidade dentro de cada um desses grupos de agentes. Diferentemente do que ocorre no caso em que os interesses são simétricos, no lado vendedor não ocorre autosseleção dos participantes e a plataforma passa a ter um papel de certificação dos vendedores, criando ambientes de qualidade selecionada onde um preço maior pode ser cobrado dos compradores. / This thesis has three papers related to the subject in the title. The first one, an econometric paper, evaluates the impact of a break of exclusivity promoted by Brazilian authorities in the payment card acquiring industry in 2010. We use two frameworks: in one of them, we try to identify categories of merchants to use as control group, while in the other we decompose prices into markup and marginal cost elements. The estimations employ a dataset of individual merchants with information for the largest ones in each category. The results indicate success in promoting some competition. In the second paper, we argue that undue charges made by financial institutions may be a form of price discrimination, since their reversion requires effort from consumers. Given that in such case the optimal undue charges depend on consumers profiles, we build a likelihood function based test to show how information on complaints might be used to detect this sort of behavior, even when the relevant authority knows less about clients than the financial institution. The third one, an applied theoretical paper, analyses the behavior of commercial platforms in two-sided markets where the roles of buyers and sellers are well defined and there is heterogeneity within each of these groups of agents. Differently from what happens in a setting with symmetric interests, in the seller side no self-selection takes place and the platform gains an important quality certification role, creating spaces for trade where seller quality is higher and buyers are willing to pay more.