871 resultados para Investimentos - Administração - Modelos matemáticos


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This paper studies the increase in the rate of informal workers in the Brazilian economy that occurred between 1985 and 1999. We develop an overlapping generations model with incomplete markets in which agents are ex-post heterogeneous. We calibrate it to match some features of the Brazilian economy for 1985. We conduct a policy experiment which reproduces the 1988 constitution reforms that increased the retirement benefits and labor costs in the formal sector. We show that these reforms can explain the increase in informal labor. Then, we conduct a policy experiment and analyze its impact on the Brazilian economy.

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In this paper we study the pricing problem of derivatives written in terms of a two dimensional time{changed L¶evy processes. Then, we examine an existing relation between prices of put and call options, of both the European and the American type. This relation is called put{call duality. It includes as a particular case, the relation known as put{call symmetry. Necessary and su±cient conditions for put{call symmetry to hold are shown, in terms of the triplet of local charac- teristic of the Time{changed L¶evy process. In this way we extend the results obtained in Fajardo and Mordecki (2004) to the case of time{changed Lévy processes.

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We study an intertemporal asset pricing model in which a representative consumer maximizes expected utility derived from both the ratio of his consumption to some reference level and this level itself. If the reference consumption level is assumed to be determined by past consumption levels, the model generalizes the usual habit formation specifications. When the reference level growth rate is made dependent on the market portfolio return and on past consumption growth, the model mixes a consumption CAPM with habit formation together with the CAPM. It therefore provides, in an expected utility framework, a generalization of the non-expected recursive utility model of Epstein and Zin (1989). When we estimate this specification with aggregate per capita consumption, we obtain economically plausible values of the preference parameters, in contrast with the habit formation or the Epstein-Zin cases taken separately. All tests performed with various preference specifications confirm that the reference level enters significantly in the pricing kernel.

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We study the effect of social embeddedness on voter turnout by investigating the role of information about other voters’ decisions. We do so in a participation game, where some voters (‘receivers’) are told about some other voters’ (‘senders’) turnout decision at a first stage of the game. Cases are distinguished where the voters support the same or different candidates or where they are uncertain about each other’s preferences. Our experimental results show that such information matters. Participation is much higher when information is exchanged than when it is not. Senders strategically try to use their first mover position and some receivers respond to this.

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This paper investigates heterogeneity in the market assessment of public macro- economic announcements by exploring (jointly) two main mechanisms through which macroeconomic news might enter stock prices: instantaneous fundamental news im- pacts consistent with the asset pricing view of symmetric information, and permanent order ow e¤ects consistent with a microstructure view of asymmetric information related to heterogeneous interpretation of public news. Theoretical motivation and empirical evidence for the operation of both mechanisms are presented. Signi cant in- stantaneous news impacts are detected for news related to real activity (including em- ployment), investment, in ation, and monetary policy; however, signi cant order ow e¤ects are also observed on employment announcement days. A multi-market analysis suggests that these asymmetric information e¤ects come from uncertainty about long term interest rates due to heterogeneous assessments of future Fed responses to em- ployment shocks.

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Wilson [16] introduced a general methodology to deal with monopolistic pricing in situations where customers have private information on their tastes (‘types’). It is based on the demand profile of customers: For each nonlinear tariff by the monopolist the demand at a given level of product (or quality) is the measure of customers’ types whose marginal utility is at least the marginal tariff (‘price’). When the customers’ marginal utility has a natural ordering (i.e., the Spence and Mirrlees Condition), such demand profile is very easy to perform. In this paper we will present a particular model with one-dimensional type where the Spence and Mirrlees condition (SMC) fails and the demand profile approach results in a suboptimal solution for the monopolist. Moreover, we will suggest a generalization of the demand profile procedure that improves the monopolist’s profit when the SMC does not hold.

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In da Costa et al. (2006) we have shown how a same pricing kernel can account for the excess returns of the S&:P500 over the US short term bond and of the uncovered over the covered trading of foreign government bonds. In this paper we estimate and test the overidentifying restrictiom; of Euler equations associated with "ix different versions of the Consumption Capital Asset Pricing I\Iodel. Our main finding is that the same (however often unreasonable) values for the parameters are estimated for ali models in both nmrkets. In most cases, the rejections or otherwise of overidentifying restrictions occurs for the two markets, suggesting that success and failure stories for the equity premium repeat themselves in foreign exchange markets. Our results corroborate the findings in da Costa et al. (2006) that indicate a strong similarity between the behavior of excess returns in the two markets when modeled as risk premiums, providing empirical grounds to believe that the proposed preference-based solutions to puzzles in domestic financiaI markets can certainly shed light on the Forward Premium Puzzle.

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We consider an exchange economy under incomplete financiaI markets with purely financiaI securities and finitely many agents. When portfolios are not constrained, Cass [4], Duffie [7] and Florenzano-Gourdel [12] proved that arbitrage-free security prices fully characterize equilibrium security prices. This result is based on a trick initiated by Cass [4] in which one unconstrained agent behaves as if he were in complete markets. This approach is unsatisfactory since it is asymmetric and no more valid when every agent is subject to frictions. We propose a new and symmetric approach to prove that arbitrage-free security prices still fully characterize equilibrium security prices in the more realistic situation where the financiaI market is constrained by convex restrictions, provided that financiaI markets are collectively frictionless.

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This paper examines the current Chilean and Brazilian pension markets, how these pension markets are structured, how they have historically invested their portfolios in ETFs and how they utilize Exchange Traded Funds (ETFs). This investigation will give an overview of the current pension landscape in each country, ETFs and ETF managers in the region, as well as distribution allowances and regulations for ETF providers within the region. Finally it will offer insights throughout that will be useful to those building a business or creating an expansion plan in Brazil or Chile.

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This paper aims to bring more information related to the critical question "how IT areas of insurance companies are defining and delivering their strategic initiatives Portfolios?" and make conclusions based on the collected data. To reach these interpretations, it is composed of a theoretical investigation on the theme, a strategy delineation for the research methodology and a conclusion presentation based on the findings. In this last part, this study concluded that explored organization does not applied a sufficient number of best practices answering the critical question as "the company is not mature on this subject".

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A formação de emulsão de água-em-óleo gera um significativo incremento na viscosidade, o que afeta diretamente a produção do poço, pois aumenta a perda de carga ao longo da linha de produção, dificultando o escoamento e diminuindo a produção de óleo. A presença e natureza da emulsão, e seu impacto na reologia do petróleo, podem determinar a viabilidade econômica e técnica dos processos envolvidos. A medida que a fração de água aumenta e a temperatura é reduzida, o comportamento das emulsões se torna cada vez mais não-Newtoniano. A decorrência disso, é que a temperatura e a taxa de cisalhamento passam a ter maior impacto na variação da viscosidade das emulsões. Nesse estudo são propostos novos métodos que levam em conta essas variáveis. Os dados reológicos experimentais de 15 petróleos leves foram utilizados para avaliar o desempenho dos modelos existentes na literatura e compará-los com os novos métodos propostos nesse estudo.

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Este trabalho investiga as recompras de ações no Brasil pelo prisma da reputação das empresas anunciadoras. Por meio de uma base de dados ainda inexplorada, o formulário de referência anual, que possibilita a diferenciação dos anúncios de recompras pelas quantidades efetivamente compradas. Com metodologia de estudo de evento e regressão, foram analisados os anúncios de recompras de ações da própria companhia em mercado aberto para o período compreendido entre os anos de 2007 a 2014. Os principais resultados encontrados foram à existência de reputação para empresas que apresentam uma taxa efetiva de recompra mais elevada e uma penalização para as empresas que apresentam baixas taxas efetivas de recompra em anúncios anteriores, quanto mais próximo de zero a taxa efetiva de recompra do anuncio anterior, menor é o efeito de um novo anúncio. Por fim, foi encontrado retorno anormal acumulado significativo no mercado acionário brasileiro para empresas que anunciam recompra de ações próprias no mercado aberto de 1,12% no primeiro dia, 1,56% no quinto dia e 1,97% ao final do primeiro mês. Para eventos com histórico, foi de 0,98% no primeiro dia, 1,33% no quinto dia e 1,38% ao final do primeiro mês. Já para o caso nos quais os eventos foram antecedidos imediatamente por anúncios de recompra com taxas efetivas de recompras de no mínimo 70%, foi de 1,42% no primeiro dia, 2,70% no quinto dia e 5,09% ao final do primeiro mês.

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This research is to be considered as an implementation of Goetzmann and Jorion (1999). In order to provide a more realistic scenario, we have implemented a Garch (1,1) approach for the residuals of returns and a multifactor model thus to better replicate the systematic risk of a market. The new simulations reveal some new aspects of emerging markets’ expected returns: the unpredictability of the emerging markets’ returns with the global factor does not depend on the year of emergence and that the unsystematic risk explains the returns of emerging markets for a much larger period of time. The results also reveal the high impact of Exchange rate, Commodities index and of the Global factor in emerging markets’ expected return.

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Este trabalho se propõe a estudar as implicações macroeconômicas da existência do BNDES na economia. Construímos aqui um modelo DSGE contemplando as características do BNDES e realizamos exercícios sobre o mesmo. Este é o primeiro trabalho a analisar o impacto de curto prazo do BNDES, sendo essa sua contribuição central. Constatamos aqui que o BNDES atua de forma a amplificar os choques de produtividade sobre a economia e reduz a eficácia da política monetária.