Submitted by Caio Teles (caio_act@hotmail.com) on 2013-09-26T18:52:08Z No. of bitstreams: 1 Dissertação - Caio.pdf: 249330 bytes, checksum: a3aa165cfa955b84e1621a3c404da19c (MD5) / Approved for entry into archive by Janete de Oliveira Feitosa (janete.feitosa@fgv.br) on 2013-09-27T13:32:40Z (GMT) No. of bitstreams: 1 Dissertação - Caio.pdf: 249330 bytes, checksum: a3aa165cfa955b84e1621a3c404da19c (MD5) / Approved for entry into archive by Marcia Bacha (marcia.bacha@fgv.br) on 2013-09-30T12:55:22Z (GMT) No. of bitstreams: 1 Dissertação - Caio.pdf: 249330 bytes, checksum: a3aa165cfa955b84e1621a3c404da19c (MD5) / Made available in DSpace on 2013-09-30T12:55:31Z (GMT). No. of bitstreams: 1 Dissertação - Caio.pdf: 249330 bytes, checksum: a3aa165cfa955b84e1621a3c404da19c (MD5) Previous issue date: 2013-06-28 / This paper analyzes the distribution of money holdings in a commo dity money search-based mo del with intermediation. Intro ducing heterogeneity of costs to the Kiyotaki e Wright ( 1989 ) mo del, Cavalcanti e Puzzello ( 2010) gives rise to a non-degenerated distribution of money. We extend further this mo del intro ducing intermediation in the trading pro cess. We show that the distribution of money matters for savings decisions. This gives rises to a xed p oint problem for the saving function that di cults nding the optimal solution. Through some examples, we show that this friction shrinks the distribution of money. In contrast to the Cavalcanti e Puzzello ( 2010 ) mo del, the optimal solution may not present the entire surplus going to the consumer. At the end of the pap er, we present a strong result, for a su cient large numb er of intermediaries the distribution of money is degenerated.

<p> In this thesis, we investigate and characterize policies for task allocation to teams of agents in settings with heterogeneity and risk. We first consider a scenario consisting of a set of heterogeneous mobile agents located at a base (or depot), and a set of tasks dispersed over a geographic area. The agents are partitioned into different types. The tasks are partitioned into specialized tasks that can only be done by agents of a certain type, and generic tasks that can be done by any agent. The distances between every pair of tasks are specified and satisfy the triangle inequality. Given this scenario, we address the problem of allocating these tasks among the available agents (subject to type compatibility constraints) while minimizing the maximum travel cost for any agent. We first look at the Heterogeneous Agent Cycle Problem (HACP) where agents start at a common base (or depot) and need to tour the set of tasks allocated to them before returning to the base. This problem is NP-hard, and we provide a 5-approximation algorithm. We then consider the Heterogeneous Agent Path Problem (HAPP) where agents can start from arbitrary locations and are not constrained to return to their start location. We consider two approaches to solve HAPP and provide a 15-approximation algorithm for HAPP.</p> <p> We then look at the effect of risk on path planning by considering a scenario where a mobile agent is required to collect measurements from a geographically dispersed set of sensors and return them to a base. The agent faces a risk of destruction while traversing the environment to reach the sensors and gets the reward for gathering a sensor measurement only if it successfully returns to base. We call this the Single Agent Risk Aware Task Execution (SARATE) problem. We characterize several properties of the optimal policy for the agent. We provide the optimal policy when the risk of destruction is sufficiently high and evaluate several heuristic policies via simulation. We then extend the analysis to multiple heterogeneous agents. We show that the scoring scheme is submodular when the risk is sufficiently high, and the greedy algorithm gives solutions that provide a utility that is guaranteed to be within 50% of the optimal utility. </p>

[pt] Introduzimos escolha de portfólio em um modelo com agentes heterogêneos para avaliar como isso afeta a desigualdade de riqueza. Para tanto, alteramos o modelo de Krusell e Smith (1998), incorporando uma tecnologia de produção com retornos decrescentes de escala, de forma que a firma representativa emite títulos de dívida para levantar capital para produção e depois distribui os lucros (ou prejuízos) para os acionistas. Também fazemos uso de preferências Epstein-Zin para aumentar o equity premium do modelo, aumentando a aversão ao risco dos agentes. O modelo é capaz de replicar fatos estilizados: (i) agentes mais pobres praticamente não participam do mercado de ações; (ii) os agentes investem proporções maiores de suas poupanças em ações, conforme ficam mais ricos; (iii) o retorno esperado da poupança dos agentes aumenta com a riqueza. A desigualdade de riqueza aumenta com a incorporação de escolha de portfólio dos agentes. No entanto, o impacto na desigualdade é pequeno devido ao baixo nível de equity premium gerado pelo modelo. Esse resultado se mantém mesmo quando estabelecemos valores muito altos para a aversão ao risco, e está relacionado à falta de volatilidade de consumo gerada por essa classe de modelos. Finalmente, documentamos que levar em conta decisões endógenas de portfólio potencializa os efeitos de outras fontes de desigualdade. / [en] We introduce households portfolio decisions in a heterogeneous agents model to evaluate how this affects wealth inequality. To do so, we alter the Krusell and Smith (1998) model, incorporating a decreasing returns to scale technology, so that the representative firm issues risk-free bonds to raise capital for production and distributes profits (or losses) to equity holders.We also make use of Epstein-Zin preferences to augment the model s equity premium, by increasing households risk aversion. The model is able to replicate stylized facts: (i) poorest households seldom participate in the equity markets; (ii) households allocate higher proportions of their savings to equity investments as they get wealthier; (iii) households expected return on savings increases with wealth. Inequality of wealth does increase in the model with portfolio decisions. Nevertheless, the effect on wealth inequality is small due to the low level of equity premium generated by the model. The result in unchanged even when we set very high values for risk aversion, and it is related to the lack of consumption growth volatility delivered by this class of model. Finally, we document that taking into account endogenous portfolio decisions enhances the effects of other sources of inequality.

京都大学 / 新制・課程博士 / 博士(経済学) / 甲第25075号 / 経博第682号 / 新制||経||305(附属図書館) / 京都大学大学院経済学研究科経済学専攻 / (主査)教授 西山 慎一, 教授 柴田 章久, 准教授 遊喜 一洋 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DGAM

This thesis comprises three chapters which share an emphasis on the importance of agent heterogeneity in different areas of macroeconomics. The first chapter shows that the introduction of heterogeneous risk aversion into a consumption based asset pricing model with Epstein-Zin preferences allows to replicate several features of stock markets such as the counter-cyclical variation in the equity premium and its predictability from the price dividend ratio. The second chapter complements a Mortensen-Pissarides matching model with individual savings for precautionary reasons in order to analyze the welfare effects of reforming unemployment insurance. Our fully dynamic analysis reveals significant transition costs that static comparisons miss. The third chapter is concerned with optimal capital and labor taxation when agents differ in their wage-wealth ratio. We find that if all agents are to benefit from a reform (vis-à-vis the status quo) capital taxes are abolished only after a long period. / Esta tesis se compone de tres capítulos que enfatizan en la importancia de la heterogeneidad de agentes económicos en distintas áreas de la macroeconomía. El primer capítulo demuestra que la introducción de heterogeneidad en la aversión al riesgo en un modelo de consumption based asset pricing con utilidad de tipo Epstein-Zin permite reproducir algunas regularidades empíricas de los mercados financieros como por ejemplo la variación anticíclica de la prima de riesgo y su previsibilidad a través del cociente precio-dividendos. El segundo capítulo introduce en un modelo de matching tipo Mortensen-Pissarides ahorros precaucionarios con el objetivo de analizar los efectos sobre el bienestar de reformas del seguro de desempleo. Nuestro análisis dinámico revela costes significativos de transición no presentes en comparaciones estáticas. El tercer capítulo investiga la imposición óptima de capital y trabajo cuando los agentes son heterogéneos con respecto a su cociente sueldo-patrimonio. Encontramos que, para que todos los agentes se beneficien de la reforma (respecto al status quo), el impuesto del capital debería eliminarse sólo después de un periodo largo.

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Dans le cadre d’une approche comportementale et compte tenu de la complexité des marchés financiers, cette thèse examine dans quelle mesure les réseaux orientés régissant l’interaction entre les investisseurs ainsi que leur comportement mimétique influencent leurs anticipations et la dynamique des prix. Nous proposons un marché artificiel d’actifs dans lequel des chartistes et des fondamentalistes opèrent et passent d’une stratégie d’investissement à une autre en fonction de leurs performances. Tout d’abord, nous étudions un réseau complet où l’interaction se fait de manière globale. Nous constatons que notre modèle révèle l’émergence de la volatilité excessive des prix lorsque les chartistes dominent le marché. Ensuite, nous portons notre attention sur des réseaux locaux où les agents se trouvent liés qu’à une partie des individus opérant dans le marché. Nous distinguons trois types de réseaux : le réseau régulier, le réseau petit monde et le réseau aléatoire. Puis, nous introduisons un nouveau modèle qui permet de contrôler (1) la direction du processus de « rewiring » des liens; (2) le caractère aléatoire du réseau et (3) l'asymétrie dans sa distribution des degrés en distinguant les stars des non-stars. Nous montrons que contrairement au degré du caractère aléatoire du réseau, l’asymétrie dans la distribution des degrés produit des effets opposés selon qu’il s’agit de « in-degree » ou de « out-degree ». Enfin, nous montrons comment ces analyses peuvent être utilisées pour produire des dynamiques de marché réalistes. Nous constatons que la présence d’un seuil d’imitation avec un coefficient de réaction élevé permet à notre modèle de reproduire les faits stylisés les plus importants / Within a behavioral approach and given the complexity of financial markets, the aim of this thesis is to examine the extent to which directed networks that governs the interaction among investors as well as their mimicking behavior influence their anticipations and the price dynamics. We propose an artificial asset market populated by chartists and fundamentalists who are allowed to switch from one trading strategy to the other according to their relative performances. Firstly, we study a fully connected network to test for a global interaction. We find that our benchmark model accounts for the emergence of excess volatility of asset prices when chartists dominate the market. Secondly, we restrict our focus to local interactions between investors. We generate a family of network structures that spans regular network, small world network and random network. Thirdly, we introduce a new model that allows us to control (1) the direction of the rewiring process of the links; (2) the randomness of the network; and (3) the asymmetry in its degree distribution by assuming that there are two classes of agents: stars and non-stars. We show that unlike the degree of the randomness of the network, the asymmetry in the degree distribution produces opposite effects depending on whether the network is outward or inward rewired. Finally, we address the question as to how this analysis can be used to produce realistic market dynamics. We find that the presence of a mimicking threshold with a high reaction coefficient provides a better approximation to the characteristics of the distribution of real returns and reproduces the most important stylized facts observed in financial time series

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.

Questa tesi contiene tre saggi di teoria macroeconomica. Il primo capitolo presenta una rassegna dei modelli monetari con agenti eterogenei e include una valutazione dei costi dell’inflazione in termini di welfare per agenti con reddito e ricchezza eterogenei. Il secondo capitolo studia le interazioni tra due canali di trasmissione della politica monetaria che emergono in presenza di eterogeneità: il canale del debito nominale e il canale della tassa da inflazione. Il terzo capitolo studia le relazioni tra le aspettative di crescita del reddito e gli episodi di default su debito sovrano. Questo saggio mostra come introducendo un meccanismo di apprendimento del processo stocastico che determina la sostenibilità del debito sia possibile generare una significativa volatilità del debito e riprodurre una frequenza di default empiricamente plausibile. / This thesis presents three essays in macroeconomic theory. The first chapter surveys monetary models with heterogeneous agents and contains an evaluation of heterogeneous welfare costs of inflation when agents have different income and wealth levels. The second chapter studies the interactions between two transmission channels of monetary policy that arise because of heterogeneity: the nominal debt channel and the inflation-tax net worth channel. The third chapter studies the relations between expectations of future output growth of a small open economy and sovereign defaults. This essay shows that learning of the stochastic process that drives debt sustainability induces significant debt volatility and an empirically plausible default frequency.

The thesis is divided into three chapters.1) I study how monetary policy should be optimally designed when households show financial wealth heterogeneity.Main results: thanks to its ability to affect interest payments volatility, monetary policy has real effects even in a flexible-price cashless-limit environment; second, in a setup with nominal rigidities, price stability is no longer optimal. The extent of deviation from price stability depends on the initial level of debt dispersion.2) I assess the role of housing price movements in influencing the optimal design of monetary policy. Under the optimal simple rule, housing price movements should not be a separate target variable in addition to inflation. Furthermore, the welfare loss arising from targeting housing prices becomes quantitatively more significant the higher the degree of access to the credit market.3) I analyze the effects of fiscal policy in a currency area. Results: a public spending shock in one region increases private agents demand for imports and appreciates the terms of trade; second, a countercyclical fiscal rule can restore the Taylor principle, the uniqueness of the equilibrium and reduce macro-volatility.