2 resultados para Process modeling

em Repositório digital da Fundação Getúlio Vargas - FGV


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This paper performs a thorough statistical examination of the time-series properties of the daily market volatility index (VIX) from the Chicago Board Options Exchange (CBOE). The motivation lies not only on the widespread consensus that the VIX is a barometer of the overall market sentiment as to what concerns investors' risk appetite, but also on the fact that there are many trading strategies that rely on the VIX index for hedging and speculative purposes. Preliminary analysis suggests that the VIX index displays long-range dependence. This is well in line with the strong empirical evidence in the literature supporting long memory in both options-implied and realized variances. We thus resort to both parametric and semiparametric heterogeneous autoregressive (HAR) processes for modeling and forecasting purposes. Our main ndings are as follows. First, we con rm the evidence in the literature that there is a negative relationship between the VIX index and the S&P 500 index return as well as a positive contemporaneous link with the volume of the S&P 500 index. Second, the term spread has a slightly negative long-run impact in the VIX index, when possible multicollinearity and endogeneity are controlled for. Finally, we cannot reject the linearity of the above relationships, neither in sample nor out of sample. As for the latter, we actually show that it is pretty hard to beat the pure HAR process because of the very persistent nature of the VIX index.

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Corporate governance has been in the spotlight for the past two decades, being subject of numerous researches all over the world. Governance is pictured as a broad and diverse theme, evolving through different routes to form distinct systems. This scenario together with 2 types of agency problems (investor vs. management and minorities vs. controlling shareholders) produce different definitions for governance. Usually, studies investigate whether corporate governance structures influence firm performance, and company valuation. This approach implies investors can identify those impacts and later take them into consideration when making investment decisions. However, behavioral finance theory shows that not always investors take rational decisions, and therefore the modus operandi of those professionals needs to be understood. So, this research aimed to investigate to what extent Brazilian corporate governance standards and practices influence the investment decision-making process of equity markets' professionals from the sell-side and buy-side. This exploratory study was carried out through qualitative and quantitative approaches. In the qualitative phase, 8 practitioners were interviewed and 3 dimensions emerged: understanding, pertinence and practice. Based on the interviews’ findings, a questionnaire was formulated and distributed to buy-siders and sell-siders that cover Brazilian stocks. 117 respondents from all over the world contributed to the study. The data obtained were analyzed through structural equation modeling and descriptive statistics. The 3 dimensions became 5 constructs: definition (institutionalized governance, informal governance), pertinence (relevance), practice (valuation process, structured governance assessment) The results of this thesis suggest there is no definitive answer, as the extent to which governance will influence an investment decision process will depend on a number of circumstances which compose the context. The only certainty is the need to present a “corporate governance behavior”, rather than simply establishing rules and regulations at firm and country level.