VALORIZA - Artigos em Revistas Científicas
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- Analysis of the Impact of COVID-19 Pandemic on the Intraday Efficiency of Agricultural Futures MarketsPublication . Aslam, Faheem; Ferreira, Paulo; Ali, HaiderThe investigation of the fractal nature of financial data has been growing in the literature. The purpose of this paper is to investigate the impact of the COVID-19 pandemic on the efficiency of agricultural futures markets by using multifractal detrended fluctuation analysis (MF-DFA). To better understand the relative changes in the efficiency of agriculture commodities due to the pandemic, we split the dataset into two equal periods of seven months, i.e., 1 August 2019 to 10 March 2020 and 11 March 2020 to 25 September 2020. We used the high-frequency data at 15 min intervals of cocoa, cotton, coffee, orange juice, soybean, and sugar. The findings reveal that the COVID-19 pandemic has great but varying impacts on the intraday multifractal properties of the selected agricultural future markets. In particular, the London sugar witnessed the lowest multifractality while orange juice exhibited the highest multifractality before the pandemic declaration. Cocoa became the most efficient while the cotton exhibited the minimum efficient pattern after the pandemic. Our findings show that the highest improvement is found in the market efficiency of orange juice. Furthermore, the behavior of these agriculture commodities shifted from a persistent to an antipersistent behavior after the pandemic. The information given by the detection of multifractality can be used to support investment and policy-making decisions.
- THE EFFICIENCY OF SIN STOCKS: A MULTIFRACTAL ANALYSIS OF DRUG INDICESPublication . Ferreira, Paulo Jorge SilveiraThis study provides the first evidence of market efficiency of drug indices, especially cannabis and tobacco, which are known in finance as sin markets. The multifractal detrended fluctuation analysis (MFDFA) is employed on the daily data of six cannabis and one tobacco indices in order to measure efficiency by quantifying the intensity of self-similarity. The findings confirm multifractality in all sample series. Interestingly, Dow Jones Tobacco (DJUSTB) Index shows the highest multifractality, demonstrating the lowest efficiency, whereas S&P/TSX Cannabis (SPTXCAN) Index is the most efficient of all the time series under analysis, with the lowest multifractality levels. Only the North American Marijuana (NAMMAR), Cannabis World Index Gross Total Return (CANWLDGR) and DJUSTB show persistent behavior. These findings could be of interest to policymakers and regulators to establish new reforms to improve the efficiency of these markets, as well as for actual and potential investors.
- Carbon Emissions and Brazilian Ethanol Prices: Are They Correlated? An Econophysics StudyPublication . David Quintino, Derick; Lee Burnquist, Heloisa; Jorge Silveira Ferreira, PauloBrazil is one of the largest global producers and exporters of ethanol and in 2017 launched RenovaBio, a programme aiming to mitigate greenhouse gas emissions. In parallel to this domestic scenario, there is rapid growth in the world market of carbon production, as well as complex price relations between fossil and renewable energies becoming increasingly important in recent years. The present work aims to contribute to filling a gap in knowledge about the relationship between Brazilian ethanol and other relevant energy-related commodities. We use a recent methodology (Detrended Cross-Correlation Approach—DCCA—with sliding windows) to analyze dynamically the cross-correlation levels between Brazilian ethanol prices and carbon emissions, as well as other possible-related prices, namely: sugar, Brent oil, and natural gas prices, with a sample of daily prices between January 2010 and July 2020. Our results indicate that (i) in the whole period, Brazilian ethanol has significant correlations with sugar, moderate correlation with oil in the short term, and only a weak, short-term correlation with carbon emission prices; (ii) with a sliding windows approach, the strength of the correlation between ethanol and carbon emissions varies between weak and non-significant in the short term.
- A new vision about the influence of major stock markets in CEEC indices: a bidirectional dynamic analysis using transfer entropyPublication . Ferreira, Paulo; Dionísio, Andreia; Almeida, Dora; Quintino, Derick; Aslam, FaheemThis research work aims to understand the dynamics of influence among CEEC stock market indices and between these and the US, German, UK and Chinese indices. Through a nonlinear approach, based on transfer entropy, we find strongly influential relationships between some CEEC indices and the influencing nature of the US index stands out. In addition to the complexity of causality relationships, which has a limited compatibility with purely linear analyses, we also perceive an intensification in the leadership of the big 4 from the first quarter of 2020, which suggests that the pandemic crisis may be a factor for the intensification of influence from Chinese and US indices.
- Relative Prices of Ethanol-Gasoline in the Major Brazilian Capitals: An Analysis to Support Public PoliciesPublication . David Quintino, Derick; Lee Burnquist, Heloisa; Ferreira, PauloThe use of biomass as an energy source has advanced in recent decades, given the scientific evidence that it is a solution to the environmental problems faced globally. In this context, biofuels derived from biomass have a prominent role. Among the countries where this alternative is the most promising, Brazil stands out, just behind the USA. It is, therefore, necessary to assess whether such a replacement is economically viable. For such an assessment, the behavior of the relative price of bioethanol/gasoline is crucial. In the present work, the degree of temporal persistence of relative prices, considering the existence of shocks to which they are exposed, is evaluated, considering 15 important Brazilian capitals, via the detrended fluctuation analysis (DFA). The degree of correlation is also evaluated through the detrended cross-correlation analysis (DCCA) between fuel prices in São Paulo, the capital of the most populous state and main producer of bioethanol, with the capitals of the 14 states selected for the analysis. The period of analysis takes place between 2004 and 2020. The use of DCCA with sliding windows was recently proposed and we also evaluate DFA dynamically in this way, and this, together with an extended sample in the context of Brazilian fuel prices, represents the main innovations of the present work. We found that the degree of persistence varies significantly depending on the capitals analyzed, which means that price variations are localized and demand regional stimulus policies. Furthermore, it was found that the correlation with São Paulo is less intense in the most geographically distant capitals. Such evidence is important and complementary to infer how integrated the national bioethanol market is, in order to support public policies aimed at its consolidation.
- Rare Earth Market, Electric Vehicles and Future Mobility Index: A Time-Frequency Analysis with Portfolio ImplicationsPublication . Inzamam, Ul Haq; Paulo, Ferreira; Apichit, Maneengam; Worakamol, WisetsriThis study investigates the co-movements between the Solactive Electric Vehicle and Future Mobility Index (EVFMI) and multiple rare earth elements (REEs). We applied a TVP-VAR model and bivariate wavelet coherence approach to capture co-movements both in the time and frequency domain considering short-, medium- and long-term investment horizons. Using daily returns from 1 June 2012 to 4 June 2021, the results of the TVP-VAR model show that individual REEs and the EVFMI have strong return connectedness and are heterogenous over time. The bivariate wavelet coherence approach reveals that Dysprosium, Neodymium, Praseodymium and Terbium returns have positive co-movement (in-phase) with the EVFMI in the medium-term and long-term. In contrast, Cerium, Europium, Lanthanum and Yttrium returns have negative co-movements (out-phase) with the EVFMI in the medium-term and long-term. We find strong positive co-movements between the MVIS Global Rare Earth/Strategic Metals Index (MVREMX) and EVFMI at multiple wavelet scales. Following the lead/lag relationship, Cerium, Europium and Lanthanum, Yttrium returns are leading the EVFMI, and Neodymium, Dysprosium, Praseodymium, Terbium and MVREMX returns are lagging to the EVFMI. This study, therefore, suggests heterogenous hedging and diversification properties of REEs over time and investment horizons. Specifically, Cerium, Europium, Lanthanum and Yttrium act as strong hedges in long-term investment horizons and Neodymium, Dysprosium, Praseodymium and Terbium are weak hedges or diversifiers in short-term investment horizons. These results may be of particular interest to investors and relevant to policymakers considering multiple investment horizons.
- A Giant Falls: The Impact of Evergrande on Asian Stock IndexesPublication . Almeida, Dora; Dionísio, Andreia; Enamul Haque, Muhammad; Ferreira, PauloThe economic growth of China has been driven by the development of its real estate market, especially after the 2008 crisis. This growth is mostly related to the huge housing bubble and growing amounts of sovereign debt that have been redirected to corporations in the sector. Evergrande is one of those corporations; it is a Chinese company in the construction and real estate sector, a global giant with investments in many parts of the world. Its bond default in September 2021 sounded alerts in financial markets. Several news outlets spoke of the “next Lehman Brothers”, and apprehension was very high, especially in Asian markets. This research work aims to evaluate the impact of Evergrande’s bond default on six Asian stock markets, using an event study approach. The results show a strong reaction from the markets towards the event in study, even anticipating it. Furthermore, it is worth mentioning a quick reversion to “normal” behavior, indicating the rapid absorption of information by the markets.
- Company Management in the Insurance Sector: Valuing Employees and their Work CommitmentPublication . Serrasqueiro, João; Felix, Marta; Veiga, Pedro Mota; Ferreira, Paulo Jorge Silveira; Almeida, DoraThis study focuses mainly on the role of employees in insurance companies in Portugal, analysing the importance of valuing them and their commitment to their work. Considering the above, this research aims to examine which aspects lead to greater commitment on the part of employees and what makes them feel valued within the organisations where they work. A quantitative methodology was used to fulfil this objective, and a questionnaire was applied to various employees in the insurance companies operating in the Portuguese market. The study’s results of the study highlight a positive relationship between leadership, the inclusion of employees, and their commitment to work. They also highlight that participation in decision-making positively influences their satisfaction, appreciation, and loyalty to their company. It can, therefore, be concluded that investing in employees and increasing their satisfaction and commitment is crucial for sustainable growth and organisational success.
- Temporal changes in global stock markets during COVID-19: an analysis of dynamic networksPublication . Kashif Zaheer; Faheem Aslam; Yasir Tariq Mohmand; Paulo Ferreira
- A grey-based correlation with multi-scale analysis: S&P 500 VIX and individual VIXs of large US company stocksPublication . Zhenkun Wang; Elie Bouri; Ferreira, Paulo Jorge Silveira; Syed Jawad Hussain Shahzad; Román FerrerWe provide first evidence of the multiscale comovement of correlations between the S&P 500 VIX and the VIXs of Amazon, Apple, Google, Goldman Sachs, and IBM. Using grey correlation and wavelet analysis on daily data (July 2011 - September 2021), the dynamics of grey-based cor relations vary across scales and depend on the fluctuation intensity of the medium time –frequency domains. The lead–lag relationships of VIX correlations are inconclusive about the dominant periodicity, although some evidence of weekly and monthly periodicity emerges. The pandemic affects the dynamics and lead-lag relationships. Such indications are useful for trading strategies and market-timing decisions.