scholarly journals Long-memory in asset returns and volatility: evidence from West Africa

2016 ◽  
Vol 13 (2) ◽  
pp. 24-28 ◽  
Author(s):  
Emmanuel Numapau Gyamfi ◽  
Kwabena A. Kyei ◽  
Ryan Gill

This paper measures the degree of long-memory or long-range dependence in asset returns and volatility of two stock indices in Ghana and Nigeria. The presence of long-memory opens up opportunities for abnormal returns to be made by analyzing price history of a particular market. The authors employ the Hurst exponent to measure the degree of long-memory which is evaluated by a semiparametric method, the Local Whittle estimator. The findings show strong evidence of the presence of long-memory in both returns and volatility of the indices studied, suggesting that neither of the markets in Ghana and Nigeria is weak-form efficient

2018 ◽  
Vol 13 (S340) ◽  
pp. 47-48
Author(s):  
V. Vipindas ◽  
Sumesh Gopinath ◽  
T. E. Girish

AbstractSolar Energetic Particles (SEPs) are high-energy particles ejected by the Sun which consist of protons, electrons and heavy ions having energies in the range of a few tens of keVs to several GeVs. The statistical features of the solar energetic particles (SEPs) during different periods of solar cycles are highly variable. In the present study we try to quantify the long-range dependence (or long-memory) of the solar energetic particles during different periods of solar cycle (SC) 23 and 24. For stochastic processes, long-range dependence or self-similarity is usually quantified by the Hurst exponent. We compare the Hurst exponent of SEP proton fluxes having energies (>1MeV to >100 MeV) for different periods, which include both solar maximum and minimum years, in order to find whether SC-dependent self-similarity exist for SEP flux.


2008 ◽  
Vol 11 (05) ◽  
pp. 669-684 ◽  
Author(s):  
RUIPENG LIU ◽  
T. DI MATTEO ◽  
THOMAS LUX

In this paper, we consider daily financial data from various sources (stock market indices, foreign exchange rates and bonds) and analyze their multiscaling properties by estimating the parameters of a Markov-switching multifractal (MSM) model with Lognormal volatility components. In order to see how well estimated models capture the temporal dependency of the empirical data, we estimate and compare (generalized) Hurst exponents for both empirical data and simulated MSM models. In general, the Lognormal MSM models generate "apparent" long memory in good agreement with empirical scaling provided that one uses sufficiently many volatility components. In comparison with a Binomial MSM specification [11], results are almost identical. This suggests that a parsimonious discrete specification is flexible enough and the gain from adopting the continuous Lognormal distribution is very limited.


Author(s):  
Mamdouh Abdulaziz Saleh Al-Faryan ◽  
Everton Dockery

Abstract We study the informational efficiency of the Saudi stock market (SSM), while accounting for corporate governance change, based on single, multiple, and variance ratio-based WALD tests and runs test. The main findings indicate that when the whole period is considered, the random walk hypothesis is rejected, but when divided into two sub-periods separated by the pre-corporate governance and the period marked by corporate governance change, the analysis demonstrates sub-period improvement in weak-form efficiency for the examined series. Robustness of results is verified by analysis using sector indices, which point to market efficiency. Interestingly, Hurst Exponent estimates evidence long-range dependence which suggests the predictability of stock prices and the prospect of speculative opportunities.


2009 ◽  
Vol 2009 ◽  
pp. 1-9 ◽  
Author(s):  
Ron Coleman

This paper investigates a new dynamic (i.e., space-time) model to measure aesthetic values in pathfinding for videogames. The results we report are important firstly because the artificial intelligence literature has given relatively little attention to aesthetic considerations in pathfinding. Secondly, those investigators who have studied aesthetics in pathfinding have relied largely on anecdotal arguments rather than metrics. Finally, in those cases where metrics have been used in the past, they show only that aesthetic paths are different. They provide no quantitative means to classify aesthetic outcomes. The model we develop here overcomes these deficiencies using rescaled range (R/S) analysis to estimate the Hurst exponent, . It measures long-range dependence (i.e., long memory) in stochastic processes and provides a novel well-defined mathematical classification for pathfinding. Indeed, the data indicates that aesthetic and control paths have statistically significantly distinct signatures. Aesthetic paths furthermore have more long memory than controls with an effect size that is large, more than three times that of an alternative approach. These conclusions will be of interest to researchers investigating games as well as other forms of entertainment, simulation, and in general nonshortest path motion planning.


GIS Business ◽  
2020 ◽  
Vol 15 (1) ◽  
pp. 109-126
Author(s):  
Nitin Tanted ◽  
Prashant Mistry

One of the highly controversial issues in the area of finance is “Efficient Market Hypothesis”. Efficient Market Hypothesis states that, “In an efficient market, all available price information is reflected in the stock prices and it is not possible to generate abnormal returns compared to other investors.” A lot of studies conducted previouslyto test the Efficient Market Hypothesis, confirmed the theory until recent years, when some academicians found it to be non-applicable in financial markets. According to them, it is possible to forecast the stock price movements using Technical Analysis. The results of various studies have been inconclusive and indefinite about the issue. This study attempted to test the efficiency of FMCG Sector stocks in India in its weak form. For the study, closing prices of top 10 stocks from Nifty FMCG index has been taken for the 5-year period ranging from 1st October 2014 to 30th September 2019. Wald-Wolfowitz Run test has been used to test the haphazard movements in the stock price movements. The results indicated that FMCG sector stocks does support the Efficient Market Hypothesis and exhibit efficiency in its weak form. Hence, it is not possible to accurately predict the price movements of these stocks.


Author(s):  
Jan Beran ◽  
Britta Steffens ◽  
Sucharita Ghosh

AbstractWe consider nonparametric regression for bivariate circular time series with long-range dependence. Asymptotic results for circular Nadaraya–Watson estimators are derived. Due to long-range dependence, a range of asymptotically optimal bandwidths can be found where the asymptotic rate of convergence does not depend on the bandwidth. The result can be used for obtaining simple confidence bands for the regression function. The method is illustrated by an application to wind direction data.


2021 ◽  
Vol 37 (4) ◽  
pp. 631-643
Author(s):  
Tayyaba Yousaf ◽  
Sadia Farooq ◽  
Ahmed Muneeb Mehta

Purpose The purpose of this study is to investigate whether the STOXX Europe Christian price index (SECI) follows the premise of efficient market hypothesis (EMH). Design/methodology/approach The study used daily data of SECI for the period of 15 years as its launch date i.e. 31 December 2004 to 31 December 2019. Data are analyzed by taking a full-length sample and fixed-length subsample. For subsample, the data are divided into five subsamples of three years each. Subsample analysis is important for analyzing time varying efficiency of the series, as the market is said to follow EMH if it is being efficient throughout the sample. Both type of samples is examined through linear tests including autocorrelations test and variance ratio (VR) test. Findings Tests applied conclude that SECI is weak-form efficient, which means that the prices of the index include all the relevant past information and immediately react to new information. Hence, the investors cannot earn abnormal returns. Originality/value Religion-based indices grasped the attention of investors, policymakers and academic researchers because of increased concern over ethics in business. Though the impact of religion on the economy have been studied in many ways but the efficiency of religion-based indices have been less explored. The current study is primary in its nature as it analysis the efficiency of SECI. This index is important to explore because Christianity is the world’s top religion with 2.3 billion followers around the globe.


Author(s):  
Farah Naz ◽  
Kanwal Zahra ◽  
Muhammad Ahmad ◽  
Salman Riaz

This study scrutinizes the day-of-the-week effect anomaly in the context of market and industry analysis of the Pakistan stock exchange. For this purpose, daily closing prices of KSE-100, KSE-30, and KSE-All Share Index from January 01, 2009 to December 31, 2018, have been used. Similarly, sector returns are also calculated, taking average log-returns of selected sample firms. To analyze the data ordinary least squares (OLS) regression, general generalized autoregressive conditional heteroscedasticity (GARCH) (1,1) as well as asymmetric threshold GARCH (TGARCH) and exponential GARCH (EGARCH) models have been employed to model the leverage effect of good and bad news on market volatility. The results indicate the evidence of daily seasonality, with significant Monday and Wednesday effect in PSX indices returns as well as in most of the industry returns. Monday is found to be the day with the highest average returns with the highest return volatility. The findings of the study reveal that there exists a weak form of inefficiency in the Pakistan Stock Market, which implies the possibility of earning abnormal returns by investors using timing strategies. In terms of return predictability, this study is essential for international and domestic investors and it may affect their investment strategy and return management. The results might be interesting to the financial experts as they ponder the available conditions in the capital market for financial decision-making. This study is one of its first kind that includes both indices as well as industry returns for analysis of manufacturing industries in Pakistan stock exchange.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Luis Berggrun ◽  
Emilio Cardona ◽  
Edmundo Lizarzaburu

PurposeThis article examines whether deviations from fundamental value or closed-end country fund's discounts or premiums forecast future share price returns or net asset returns.Design/methodology/approachThe main empirical (econometric) tool is a vector autoregressive (VAR) model. The authors model share price returns and net asset returns as a function of their lagged values, the discounts or premiums, and a control variable for local market returns. The authors also conduct Dickey Fuller and Granger causality tests as well as impulse response functions.FindingsIt was found that deviations from fundamental value do predict share price returns. This predictability is contrary to weak-form market efficiency. Premiums or discounts predict net asset returns but weakly.Originality/valueThe findings point to the idea that the closed-end fund market is somewhat predictable and inefficient (in its weak form) since the market appears to be able to anticipate a fund's future returns using information contained in the premiums (or discounts). In particular, the market has the ability to anticipate future behaviour because growing premiums forecast declining share price returns for one or two periods ahead.


2000 ◽  
Vol 37 (04) ◽  
pp. 1104-1109 ◽  
Author(s):  
Tilmann Gneiting

Martin and Walker ((1997) J. Appl. Prob. 34, 657–670) proposed the power-law ρ(v) = c|v|-β, |v| ≥ 1, as a correlation model for stationary time series with long-memory dependence. A straightforward proof of their conjecture on the permissible range of c is given, and various other models for long-range dependence are discussed. In particular, the Cauchy family ρ(v) = (1 + |v/c|α)-β/α allows for the simultaneous fitting of both the long-term and short-term correlation structure within a simple analytical model. The note closes with hints at the fast and exact simulation of fractional Gaussian noise and related processes.


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