Browsing by Author "Mensi, W."

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    Does bitcoin co-move and share risk with Sukuk and world and regional Islamic stock markets? Evidence using a time-frequency approach
    (Elsevier, 2020) Mensi, W.; Rehman, M. U.; Maitra, D.; Al-Yahyaee, K. H.; Şensoy, Ahmet
    This paper examines the co-movements between Bitcoin (BTC) and the Dow Jones World Stock Market Index, regional Islamic stock markets, and Sukuk markets. We apply cross wavelet transform and wavelet coherence analysis with a wavelet-based measure of value at risk. The co-movement is stronger and in the same direction at lower frequencies, suggesting the benefits from diversification with BTC are relatively less for long-term investors compared to short-term investors. Co-movement in the opposite direction at high frequencies implies better benefits of hedging in the short run through diversification in BTC and Islamic equity markets. Robustness tests show that the correlations increase as we increase from an investment horizon of two days to one of 64 days. The frequency-domain causality test shows significant causality flow from BTC to the Islamic market of Asia-Pacific, Japan, and Sukuk markets in the short term. Additionally, BTC is found to lead Asia-Pacific Islamic stock markets in the long term. Finally, we note that the benefits of portfolio diversification with BTC and Islamic assets vary across time and frequencies.
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    Dynamic risk spillovers between gold, oil prices and conventional, sustainability and Islamic equity aggregates and sectors with portfolio implications
    (Elsevier B.V., 2017) Mensi, W.; Hammoudeh, S.; Al-Jarrah, I. M. W.; Sensoy A.; Kang, S. H.
    This paper investigates the time-varying equicorrelations and risk spillovers between crude oil, gold and the Dow Jones conventional, sustainability and Islamic stock index aggregates and 10 associated disaggregated Islamic sector stock indexes (basic materials, consumer services, consumer goods, energy, financials, health care, technology, industrials, telecommunications and utilities), using the multivariate DECO-FIAPARCH model and the spillover index of Diebold and Yilmaz (2012). We also conduct a risk management analysis at the sector level for commodity-Islamic stock sector index portfolios, using different risk exposure measures. For comparison purposes, we add the aggregate conventional Dow Jones global index and the Dow Jones sustainability world index. The results show evidence of time-varying risk spillovers between these markets. Moreover, there are increases in the correlations among the markets in the aftermath of the 2008–2009 GFC. Further, the oil, gold, energy, financial, technology and telecommunications sectors are net receivers of risk spillovers, while the sustainability and conventional aggregate DJIM indexes as well as the remaining Islamic stock sectors are net contributors of risk spillovers. Finally, we provide evidence that gold offers better portfolio diversification benefits and downside risk reductions than oil. © 2017 Elsevier B.V.
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    Energy, precious metals, and GCC stock markets: Is there any risk spillover?
    (Elsevier, 2019) Al-Yahyaee, K.; Mensi, W.; Şensoy, Ahmet; Kang, S.
    We analyze dynamic return and risk spillovers between commodity futures (energy & precious metals) and the Gulf Cooperation Council (GCC) stock markets. Utilizing dynamic equicorrelation (DECO) models and the spillover index of Diebold and Yilmaz (2012), we show the existence of significant return and risk spillovers between the commodities and the GCC stock markets, particularly during the onset of the 2008–2009 global financial crisis. In addition, silver, platinum, and energy futures markets are net transmitter of returns to stock markets. Precious metals (except silver) and WTI oil are net transmitter of risk to GCC markets. Abdu Dhabi and Dubai are net transmitter of returns and risk to other markets. Moreover, portfolio management analysis shows that the mix of commodities and GCC equities provides diversification opportunities for different crisis periods. Finally, precious metal markets offer superior hedging effectiveness over energy markets for all GCC markets.
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    High-frequency asymmetric volatility connectedness between Bitcoin and major precious metals markets
    (Elsevier, 2019) Mensi, W.; Şensoy, Ahmet; Aslan, Aylin; Kang, S. H.
    This study examines the asymmetric volatility connectedness between Bitcoin and major precious metals markets (gold, silver, palladium, and platinum). We use high-frequency data with methodologies introduced by Diebold and Yilmaz (2014) and Baruník, Kočcenda, and Vácha (2017). The results show evidence of significant volatility spillover effects between Bitcoin and precious metals. Moreover, the risk spillovers vary over time and are sensitive to slowdowns in economic activity and political events (e.g., the Brexit vote and the US presidential election). Palladium is the largest net contributor of spillovers while Bitcoin is a net recipient. Finally, evidence of asymmetry in semi-volatility transmission shows that Bitcoin heavily transmits net-positive spillovers to other assets. The results of our research are of interest and importance to investors, portfolio managers, and policy-makers, as the results can readily inform their decision-making.
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    Impact of COVID-19 outbreak on asymmetric multifractality of gold and oil prices
    (Elsevier, 2020) Mensi, W.; Şensoy, Ahmet; Vo, X. V.; Kang, S. H.
    This paper examines the impacts of COVID-19 on the multifractality of gold and oil prices based on upward and downward trends. We apply the Asymmetric Multifractal Detrended Fluctuation Analysis (A-MF-DFA) approach to 15-min interval intraday data. The results show strong evidence of asymmetric multifractality that increases as the fractality scale increases. Moreover, multifractality is especially higher in the downside (upside) trend for Brent oil (gold), and this excess asymmetry has been more accentuated during the COVID-19 outbreak. Before the outbreak, the gold (oil) market was more inefficient during downward (upward) trends. During the COVID-19 outbreak period, we see that the results have changed. More precisely, we find that gold (oil) is more inefficient during upward (downward) trends. Gold and oil markets have been inefficient, particularly during the outbreak. The efficiency of gold and oil markets is sensitive to scales, market trends, and to the pandemic outbreak, highlighting the investor sentiment effect.
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    Intraday downward/upward multifractality and long memory in Bitcoin and Ethereum markets: an asymmetric multifractal detrended fluctuation analysis
    (Elsevier, 2019) Mensi, W.; Lee, Y. -J.; Al-Yahyaee, K.; Şensoy, Ahmet; Yoon, S. -M.
    This study examines high-frequency asymmetric multifractality, long memory, and weak-form efficiency for two major cryptocurrencies, namely, Bitcoin (BTC) and Ethereum (ETH), using the asymmetric multifractal detrended fluctuation analysis method to consider different market patterns. Our results show evidence of structural breaks and asymmetric multifractality. Moreover, the multifractality gap between the uptrend and downtrend is small when the time scale is small, and it increases as the time scale increases. The BTC market is more inefficient than ETH. The inefficiency is more (less) accentuated when the market follows a downward (upward) movement. The efficiency level varies based on each subperiod.