35 resultados para Sparse time-varying VAR models


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This paper aims at contributing to the research agenda on the sources of price stickiness, showing that the adoption of nominal price rigidity may be an optimal firms' reaction to the consumers' behavior, even if firms have no adjustment costs. With regular broadly accepted assumptions on economic agents behavior, we show that firms' competition can lead to the adoption of sticky prices as an (sub-game perfect) equilibrium strategy. We introduce the concept of a consumption centers model economy in which there are several complete markets. Moreover, we weaken some traditional assumptions used in standard monetary policy models, by assuming that households have imperfect information about the ineflicient time-varying cost shocks faced by the firms, e.g. the ones regarding to inefficient equilibrium output leveIs under fiexible prices. Moreover, the timing of events are assumed in such a way that, at every period, consumers have access to the actual prices prevailing in the market only after choosing a particular consumption center. Since such choices under uncertainty may decrease the expected utilities of risk averse consumers, competitive firms adopt some degree of price stickiness in order to minimize the price uncertainty and fi attract more customers fi.'

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There is strong empirical evidence that risk premia in long-term interest rates are time-varying. These risk premia critically depend on interest rate volatility, yet existing research has not examined the im- pact of time-varying volatility on excess returns for long-term bonds. To address this issue, we incorporate interest rate option prices, which are very sensitive to interest rate volatility, into a dynamic model for the term structure of interest rates. We estimate three-factor affine term structure models using both swap rates and interest rate cap prices. When we incorporate option prices, the model better captures interest rate volatility and is better able to predict excess returns for long-term swaps over short-term swaps, both in- and out-of-sample. Our results indicate that interest rate options contain valuable infor- mation about risk premia and interest rate dynamics that cannot be extracted from interest rates alone.

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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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In this paper, we show that the widely used stationarity tests such as the KPSS test have power close to size in the presence of time-varying unconditional variance. We propose a new test as a complement of the existing tests. Monte Carlo experiments show that the proposed test possesses the following characteristics: (i) In the presence of unit root or a structural change in the mean, the proposed test is as powerful as the KPSS and other tests; (ii) In the presence a changing variance, the traditional tests perform badly whereas the proposed test has high power comparing to the existing tests; (iii) The proposed test has the same size as traditional stationarity tests under the null hypothesis of stationarity. An application to daily observations of return on US Dollar/Euro exchange rate reveals the existence of instability in the unconditional variance when the entire sample is considered, but stability is found in subsamples.

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This thesis is composed of three essays referent to the subjects of macroeconometrics and Önance. In each essay, which corresponds to one chapter, the objective is to investigate and analyze advanced econometric techniques, applied to relevant macroeconomic questions, such as the capital mobility hypothesis and the sustainability of public debt. A Önance topic regarding portfolio risk management is also investigated, through an econometric technique used to evaluate Value-at-Risk models. The Örst chapter investigates an intertemporal optimization model to analyze the current account. Based on Campbell & Shillerís (1987) approach, a Wald test is conducted to analyze a set of restrictions imposed to a VAR used to forecast the current account. The estimation is based on three di§erent procedures: OLS, SUR and the two-way error decomposition of Fuller & Battese (1974), due to the presence of global shocks. A note on Granger causality is also provided, which is shown to be a necessary condition to perform the Wald test with serious implications to the validation of the model. An empirical exercise for the G-7 countries is presented, and the results substantially change with the di§erent estimation techniques. A small Monte Carlo simulation is also presented to investigate the size and power of the Wald test based on the considered estimators. The second chapter presents a study about Öscal sustainability based on a quantile autoregression (QAR) model. A novel methodology to separate periods of nonstationarity from stationary ones is proposed, which allows one to identify trajectories of public debt that are not compatible with Öscal sustainability. Moreover, such trajectories are used to construct a debt ceiling, that is, the largest value of public debt that does not jeopardize long-run Öscal sustainability. An out-of-sample forecast of such a ceiling is also constructed, and can be used by policy makers interested in keeping the public debt on a sustainable path. An empirical exercise by using Brazilian data is conducted to show the applicability of the methodology. In the third chapter, an alternative backtest to evaluate the performance of Value-at-Risk (VaR) models is proposed. The econometric methodology allows one to directly test the overall performance of a VaR model, as well as identify periods of an increased risk exposure, which seems to be a novelty in the literature. Quantile regressions provide an appropriate environment to investigate VaR models, since they can naturally be viewed as a conditional quantile function of a given return series. An empirical exercise is conducted for daily S&P500 series, and a Monte Carlo simulation is also presented, revealing that the proposed test might exhibit more power in comparison to other backtests.

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Este trabalho objetivou estudar o modelo de avaliação de empresas e projetos fundamentado na Teoria de Opções Reais. Foi demonstrado que, dado a existência de incertezas sobre os acontecimentos futuros e a possibilidade de os investidores modificarem suas decisões no decorrer do tempo, os modelos tradicionais de avaliação erram, pois desconsideram as modificações que a taxa de desconto utilizada sofre em função de uma decisão tomada sobre uma opção qualquer existente. Por outro lado, com a utilização da Teoria de Opções Reais é possível identificar estas opções e avaliá-las de forma correta. Apresentou-se um exemplo em que determinado investimento foi avaliado pelo modelo de Desconto dos Fluxos de Caixa e pela Teoria de Opções Reais, o qual demonstrou que os modelos tradicionais erram ao não considerar e valorar as opções reais existentes, confirmando desta forma a proposição inicial do trabalho.

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This article develops an econometric model in order to study country risk behavior for six emerging economies (Argentina, Mexico, Russia, Thailand, Korea and Indonesia), by expanding the Country Beta Risk Model of Harvey and Zhou (1993), Erb et. al. (1996a, 1996b) and Gangemi et. al. (2000). Toward this end, we have analyzed the impact of macroeconomic variables, especially monetary policy, upon country risk, by way of a time varying parameter approach. The results indicate an inefficient and unstable effect of monetary policy upon country risk in periods of crisis. However, this effect is stable in other periods, and the Favero-Giavazzi effect is not verified for all economies, with an opposite effect being observed in many cases.

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I study the asset-pricing implications in an cnviromncnt with feedback traders and rational arbitrageurs. Feedback traders are defined as possible naive investors who buy after a raise in prices and sell after a drop in prices. I consider two types of feedback strategies: (1) short-term (SF), motivated by institutional rulcs as top-losscs and margin calls and (2) long-tcrm (LF), motivated by representativeness bias from non-sophisticated investors. Their presence in the market follows a stochastic regime swift process. Short lived assumption for the arbitrageurs prevents the correction of the misspricing generated by feedback strategies. The estimated modcl using US data suggests that the regime switching is able to capture the time varying autocorrclation of returns. The segregation of feedback types helps to identify the long term component that otherwise would not show up due to the large movements implied by the SF typc. The paper also has normativo implications for practioners since it providos a methodology to identify mispricings driven by feedback traders.

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This article aims to test the hypothesis of contagion between the indices of nancial markets from the United States to Brazil, Japan and England for the period 2000 to 2009. Time varying copulas were used to capture the impact of Sub-prime crisis in the dependence between markets. The implemented model was a ARMA(1,0) st-ARCH(1,2) to the marginal distributions and Normal and Joe Clayton (SJC) copulas for the joint distribution. The results obtained allow to conclude that both for the gaussiana copula and for the SJC copula there is evidence of contagion between the American market and the Brazilian market. For the other two markets Londoner and Japanese, the evidence of the presence of contagion between these markets and the American has not been suf ciently clear in both copula

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O objetivo dessa dissertação é estabelecer um modelo quantitativo de gestão de riscos estratégicos de um ativo de produção de petróleo, notadamente o valor em risco do seu fluxo de caixa e de sua rentabilidade. Para tanto, foi utilizado um modelo de fluxo de caixa onde a receita operacional foi definida como variável estocástica. A receita operacional foi estimada a partir de uma função de perdas que descreve o volume de produção de petróleo, e de uma trajetória de preços definida por um modelo geométrico browniano sem reversão a média e com volatilidade descrita por um processo GARCH. Os resultados obtidos demonstram que o modelo proposto é capaz de fornecer informações importantes para a gestão de riscos de ativos de produção de petróleo ao passo que permite a quantificação de diferentes fatores de risco que afetam a rentabilidade das operações. Por fim, o modelo aqui proposto pode ser estendido para a avaliação do risco financeiro e operacional de um conjunto de ativos de petróleo, considerando sua estrutura de dependência e a existência de restrições de recursos financeiros, físicos e humanos.

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O conceito de paridade coberta de juros sugere que, na ausência de barreiras para arbitragem entre mercados, o diferencial de juros entre dois ativos, idênticos em todos os pontos relevantes, com exceção da moeda de denominação, na ausência de risco de variação cambial deve ser igual a zero. Porém, uma vez que existam riscos não diversificáveis, representados pelo risco país, inerentes a economias emergentes, os investidores exigirão uma taxa de juros maior que a simples diferença entre as taxas de juros doméstica e externa. Este estudo tem por objetivo avaliar se o ajustamento das condições de paridade coberta de juros por prêmios de risco é suficiente para a validação da relação de não-arbitragem para o mercado brasileiro, durante o período de 2007 a 2010. O risco país contamina todos os ativos financeiros emitidos em uma determinada economia e pode ser descrito como a somatória do risco de default (ou risco soberano) e do risco de conversibilidade percebidos pelo mercado. Para a estimação da equação de não arbitragem foram utilizadas regressões por Mínimos Quadrados Ordinários, parâmetros variantes no tempo (TVP) e Mínimos Quadrados Recursivos, e os resultados obtidos não são conclusivos sobre a validação da relação de paridade coberta de juros, mesmo ajustando para prêmio de risco. Erros de medidas de dados, custo de transação e intervenções e políticas restritivas no mercado de câmbio podem ter contribuído para este resultado.

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Este trabalho tem por objetivo avaliar para o caso brasileiro uma das mais importantes propriedades esperadas de um núcleo: ser um bom previsor da inflação plena futura. Para tanto, foram utilizados como referência para comparação dois modelos construídos a partir das informações mensais do IPCA e seis modelos VAR referentes a cada uma das medidas de núcleo calculadas pelo Banco Central do Brasil. O desempenho das previsões foi avaliado pela comparação dos resultados do erro quadrático médio e pela aplicação da metodologia de Diebold-Mariano (1995) de comparação de modelos. Os resultados encontrados indicam que o atual conjunto de medidas de núcleos calculado pelo Banco Central não atende pelos critérios utilizados neste trabalho a essa característica desejada.

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Este trabalho analisa a importância dos fatores comuns na evolução recente dos preços dos metais no período entre 1995 e 2013. Para isso, estimam-se modelos cointegrados de VAR e também um modelo de fator dinâmico bayesiano. Dado o efeito da financeirização das commodities, DFM pode capturar efeitos dinâmicos comuns a todas as commodities. Além disso, os dados em painel são aplicados para usar toda a heterogeneidade entre as commodities durante o período de análise. Nossos resultados mostram que a taxa de juros, taxa efetiva do dólar americano e também os dados de consumo têm efeito permanente nos preços das commodities. Observa-se ainda a existência de um fator dinâmico comum significativo para a maioria dos preços das commodities metálicas, que tornou-se recentemente mais importante na evolução dos preços das commodities.

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This paper investigates the relationship between consumer demand and corporate performance in several consumer industries in the UK, using two independent datasets. It uses data on consumer expenditures and the retail price index to estimate Almost Ideal Demand Systems on micro-data and compute timevarying price elasticities of demand for disaggregated commodity groups. Then, it matches the product definitions to the Standard Industry Classification and uses the estimated elasticities to investigate the impact of consumer behaviour on firm-level profitability equations. The time-varying household characteristics are ideal instruments for the demand effects in the firms' supply equation. The paper concludes that demand elasticities have a significant and tangible impact on the profitability of UK firms and that this impact can shed some light on the relationship between market structure and economic performance.

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This work evaluates empirically the Taylor rule for the US and Brazil using Kalman Filter and Markov-Switching Regimes. We show that the parameters of the rule change significantly with variations in both output and output gap proxies, considering hidden variables and states. Such conclusions call naturally for robust optimal monetary rules. We also show that Brazil and US have very contrasting parameters, first because Brazil presents time-varying intercept, second because of the rigidity in the parameters of the Brazilian Taylor rule, regardless the output gap proxy, data frequency or sample data. Finally, we show that the long-run inflation parameter of the US Taylor rule is less than one in many periods, contrasting strongly with Orphanides (forthcoming) and Clarida, Gal´i and Gertler (2000), and the same happens with Brazilian monthly data.