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Purpose This study aims to examine the spillover effects of the mean and volatility between oil prices and stock indices of six Gulf Cooperation Council (GCC) countries (UAE, Kuwait, Saudi Arabia, Qatar, Oman and Bahrain). Design/methodology/approach Over the period 2008–2019, a bivariate VARMA-GARCH-ADCC model was combined with the maximal overlap discrete wavelet transform technique filter to shed light on a wide range of possible spillover effects in the mean and variances of level prices at various time horizons. Findings The authors find that the spillover effects between oil prices and the GCC stock markets are time-varying and spread across various time horizons. Besides, oil prices and stock market indices are directly impacted by their own shocks and variations and indirectly influenced by other price volatilities and wavelet scales. The linkages in volatility spillovers between oil prices and the GCC stock markets occur in the short-term, midterm and long-term horizons. More specifically, the results also show that the asymmetric estimates are statistically significant for the associations between oil prices and each stock market in the GCC countries. This implies that negative shocks play a more vital role than positive shocks in driving the dynamic condition correlations between oil and stock markets under study. Practical implications The significant interrelatedness between oil prices and each stock market in the GCC countries has important implications for investors, portfolio managers, and other market participants. They can use the findings of this research to create the best oil-GCC stock portfolios and predict more precisely the volatility spillover patterns in constructing their hedging strategies. Originality/value In several ways, this study differs from previous research. First, while previous empirical studies of the dynamic link between oil prices and stock markets have focused primarily on developed or emerging markets, the focus of this is on six GCC countries. Second, the linkage between oil prices and stock markets is typically studied at the original data level in the time domain in relevant literature, while frequency information is overlooked. Therefore, the current study examines this relationship from a multiscale perspective. Third, in this paper, to capture a wide range of possible spillover effects in the mean and variance of level prices at multiple wavelet scales, the authors use a VARMA-GARCH-ADCC model in conjunction with wavelet multiresolution analysis. Additionally, this article also applies wavelet hedge ratio and wavelet hedge portfolio analysis at various time horizons.

This case presents a patient with ectopic secretion of adrenocorticotrophic hormone from a carcinoid tumor resulting in severe hypertension, posterior reversible encephalopathy syndrome (PRES), and refractory status epilepticus. Secondary hypertension may be difficult to identify in critically ill patients. Severely uncontrolled hypertension presenting with PRES caused by Cushing syndrome is rare but should be considered. Management requires the correct diagnosis and specific treatment. A missed or delayed diagnosis can lead to serious consequences and disability.

The main objective of this paper is to study the impact of capital structure and capital ownership form of SOEs after equitization. We have considered all 137 state-owned companies after equitization for which data can be collected during the period from 2007 to 2017. These encompass companies in different industries listed on the HOSE (Ho Chi Minh City) and HNX (Hanoi) stock exchanges. To this end, we have applied REM and FEM models and corrected for variance with the GLS and FEM models. Our findings reveal that the variable leverage (LEV) has a negative impact on ROA, but, interestingly, has a positive impact on ROE and Tobin’s Q. Growth rate (GROWTH) have a positive effect on both ROA and Tobin’s Q. State ownership (SO) has only positive impact on ROA. Meanwhile, the company size variable (SIZE) has a positive impact on Tobin’s Q. In addition, in relation to our examination of how the domestic and foreign resources might impact on the profitability ratio, we have observed that the domestic equity ratio has a positive impact on both ROA and ROE whereas the foreign ownership ratio has a negative impact on both ROA and ROE.

This study empirically investigates the volatility pattern of Vietnam stock market based on time series data which consists of daily closing prices of VN-Index during the period 2005-2016. The analysis has been done using both symmetric and asymmetric Generalized Autoregressive Conditional Heteroscedastic (GARCH) models. Based on Akaike Information Criterion (AIC) and Schwarz Information Criterion (SIC) criteria, the study proves that GARCH (1,1) and EGARCH (1,1) are the most appropriate model to measure the symmetric and asymmetric volatility of VN-Index respectively. The study also provides evidence of the existence of asymmetric effects (leverage) via the parameters of the EGARCH (1,1) model that show that negative shocks have significant effects on conditional variance (fluctuation). Meanwhile, in the TGARCH (1,1) model, the findingss are not as expected. This study also provides investors with a tool to forecast the rate of return of the stock market. At the same time, the findings will help investors determine the profitability and volatility of the market so that they can make the right decisions on holding the securities.