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The dynamics of bonds, commodities and bitcoin based on NARDL approach

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  • Bouteska, Ahmed
  • Hassan, M. Kabir
  • Rashid, Mamunur
  • Bilgin, Mehmet Hüseyin

Abstract

Asset market dynamic interconnectedness poses significant challenges to investors, fund managers, and policymakers, particularly in periods of prolonged uncertainty and economic crisis. This study investigates the asymmetric connection between the Bitcoin, gold, and oil markets and the bond markets in the United States, Australia, China, and the European Union. The study employed nonlinear autoregressive distributed lag (NARDL) on data ranging from January 1, 2017, to January 26, 2023, that accounted for the COVID-19 pandemic period and the Russian-Ukraine war. The results indicate that a fall in the Bitcoin price leads to a rise in bond prices, most profoundly in the European Union, where a 1% rise in the Bitcoin price leads to a 0.032% fall in bond prices. Similarly, the oil price index indicated a negative asymmetric shock in bond prices, with the most profound rise in the US bond market. The gold market index exhibited a positive connection to the bond market (US bond market falls by 0.476%) as the market overreacts to a fall in prices rather than a rise, and often in the long run rather than the short run, except for Bitcoin. The Bitcoin and oil markets act as strong safe-havens, while gold plays the role of a weak hedge during the pandemic and the Russia-Ukraine war. While our results are consistent over multiplier impact and stability tests, fund managers may find these significant due to the involvement of Russia and Ukraine as the two largest producers and exporters of several important commodities and energy. We discuss practical implications of our findings.

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  • Bouteska, Ahmed & Hassan, M. Kabir & Rashid, Mamunur & Bilgin, Mehmet Hüseyin, 2024. "The dynamics of bonds, commodities and bitcoin based on NARDL approach," The Quarterly Review of Economics and Finance, Elsevier, vol. 94(C), pages 58-70.
  • Handle: RePEc:eee:quaeco:v:94:y:2024:i:c:p:58-70
    DOI: 10.1016/j.qref.2023.12.013
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    as
    1. Wu, Shan & Tong, Mu & Yang, Zhongyi & Derbali, Abdelkader, 2019. "Does gold or Bitcoin hedge economic policy uncertainty?," Finance Research Letters, Elsevier, vol. 31(C), pages 171-178.
    2. Gupta, Rangan & Subramaniam, Sowmya & Bouri, Elie & Ji, Qiang, 2021. "Infectious disease-related uncertainty and the safe-haven characteristic of US treasury securities," International Review of Economics & Finance, Elsevier, vol. 71(C), pages 289-298.
    3. Achraf Ghorbel & Ahmed Jeribi, 2021. "Volatility spillovers and contagion between energy sector and financial assets during COVID-19 crisis period," Eurasian Economic Review, Springer;Eurasia Business and Economics Society, vol. 11(3), pages 449-467, September.
    4. Boungou, Whelsy & Yatié, Alhonita, 2022. "The impact of the Ukraine–Russia war on world stock market returns," Economics Letters, Elsevier, vol. 215(C).
    5. Pesaran, M. H. & Shin, Y. & Smith, R. J., 1996. "Testing for the 'Existence of a Long-run Relationship'," Cambridge Working Papers in Economics 9622, Faculty of Economics, University of Cambridge.
    6. Kaul, Aditya & Sapp, Stephen, 2006. "Y2K fears and safe haven trading of the U.S. dollar," Journal of International Money and Finance, Elsevier, vol. 25(5), pages 760-779, August.
    7. Baur, Dirk G. & McDermott, Thomas K., 2010. "Is gold a safe haven? International evidence," Journal of Banking & Finance, Elsevier, vol. 34(8), pages 1886-1898, August.
    8. Sun, Qinglin & Zhang, Zhiyuan, 2023. "Can art hedge against economic policy uncertainty?: New insights through the NARDL model," Finance Research Letters, Elsevier, vol. 54(C).
    9. Ustaoglu, Erkan, 2023. "Diversification, hedge, and safe-haven properties of gold and bitcoin with portfolio implications during the Russia–Ukraine war," Resources Policy, Elsevier, vol. 84(C).
    10. Dirk G. Baur & Brian M. Lucey, 2010. "Is Gold a Hedge or a Safe Haven? An Analysis of Stocks, Bonds and Gold," The Financial Review, Eastern Finance Association, vol. 45(2), pages 217-229, May.
    11. M. Hashem Pesaran & Yongcheol Shin & Richard J. Smith, 2001. "Bounds testing approaches to the analysis of level relationships," Journal of Applied Econometrics, John Wiley & Sons, Ltd., vol. 16(3), pages 289-326.
    12. Selmi, Refk & Mensi, Walid & Hammoudeh, Shawkat & Bouoiyour, Jamal, 2018. "Is Bitcoin a hedge, a safe haven or a diversifier for oil price movements? A comparison with gold," Energy Economics, Elsevier, vol. 74(C), pages 787-801.
    13. Bouri, Elie & Gupta, Rangan & Tiwari, Aviral Kumar & Roubaud, David, 2017. "Does Bitcoin hedge global uncertainty? Evidence from wavelet-based quantile-in-quantile regressions," Finance Research Letters, Elsevier, vol. 23(C), pages 87-95.
    14. Filis, George & Degiannakis, Stavros & Floros, Christos, 2011. "Dynamic correlation between stock market and oil prices: The case of oil-importing and oil-exporting countries," International Review of Financial Analysis, Elsevier, vol. 20(3), pages 152-164, June.
    15. Shen, Yifan & Shi, Xunpeng & Variam, Hari Malamakkavu Padinjare, 2018. "Risk transmission mechanism between energy markets: A VAR for VaR approach," Energy Economics, Elsevier, vol. 75(C), pages 377-388.
    16. Shahzad, Syed Jawad Hussain & Hernandez, Jose Areola & Rehman, Mobeen Ur & Al-Yahyaee, Khamis Hamed & Zakaria, Muhammad, 2018. "A global network topology of stock markets: Transmitters and receivers of spillover effects," Physica A: Statistical Mechanics and its Applications, Elsevier, vol. 492(C), pages 2136-2153.
    17. Corbet, Shaen & Meegan, Andrew & Larkin, Charles & Lucey, Brian & Yarovaya, Larisa, 2018. "Exploring the dynamic relationships between cryptocurrencies and other financial assets," Economics Letters, Elsevier, vol. 165(C), pages 28-34.
    18. M. Hashem Pesaran & Yongcheol Shin, 2002. "Long-Run Structural Modelling," Econometric Reviews, Taylor & Francis Journals, vol. 21(1), pages 49-87.
    19. Bouri, Elie & Gupta, Rangan & Lahiani, Amine & Shahbaz, Muhammad, 2018. "Testing for asymmetric nonlinear short- and long-run relationships between bitcoin, aggregate commodity and gold prices," Resources Policy, Elsevier, vol. 57(C), pages 224-235.
    20. Nader Trabelsi, 2018. "Are There Any Volatility Spill-Over Effects among Cryptocurrencies and Widely Traded Asset Classes?," JRFM, MDPI, vol. 11(4), pages 1-17, October.
    21. Ciner, Cetin & Gurdgiev, Constantin & Lucey, Brian M., 2013. "Hedges and safe havens: An examination of stocks, bonds, gold, oil and exchange rates," International Review of Financial Analysis, Elsevier, vol. 29(C), pages 202-211.
    22. Nguyen, Quynh Nga & Bedoui, Rihab & Majdoub, Najemeddine & Guesmi, Khaled & Chevallier, Julien, 2020. "Hedging and safe-haven characteristics of Gold against currencies: An investigation based on multivariate dynamic copula theory," Resources Policy, Elsevier, vol. 68(C).
    23. Klein, Tony & Pham Thu, Hien & Walther, Thomas, 2018. "Bitcoin is not the New Gold – A comparison of volatility, correlation, and portfolio performance," International Review of Financial Analysis, Elsevier, vol. 59(C), pages 105-116.
    24. Basher, Syed Abul & Sadorsky, Perry, 2016. "Hedging emerging market stock prices with oil, gold, VIX, and bonds: A comparison between DCC, ADCC and GO-GARCH," Energy Economics, Elsevier, vol. 54(C), pages 235-247.
    25. Ali, Fahad & Sensoy, Ahmet & Goodell, John W., 2023. "Identifying diversifiers, hedges, and safe havens among Asia Pacific equity markets during COVID-19: New results for ongoing portfolio allocation," International Review of Economics & Finance, Elsevier, vol. 85(C), pages 744-792.
    26. Huang, Yingying & Duan, Kun & Mishra, Tapas, 2021. "Is Bitcoin really more than a diversifier? A pre- and post-COVID-19 analysis," Finance Research Letters, Elsevier, vol. 43(C).
    27. Urquhart, Andrew & Zhang, Hanxiong, 2019. "Is Bitcoin a hedge or safe haven for currencies? An intraday analysis," International Review of Financial Analysis, Elsevier, vol. 63(C), pages 49-57.
    28. Syed Jawad Hussain Shahzad & Elie Bouri & Sang Hoon Kang & Tareq Saeed, 2021. "Regime specific spillover across cryptocurrencies and the role of COVID-19," Financial Innovation, Springer;Southwestern University of Finance and Economics, vol. 7(1), pages 1-24, December.
    29. Liu, Weiyi, 2019. "Portfolio diversification across cryptocurrencies," Finance Research Letters, Elsevier, vol. 29(C), pages 200-205.
    30. G. Andrew Karolyi, 2016. "Home Bias, an Academic Puzzle," Review of Finance, European Finance Association, vol. 20(6), pages 2049-2078.
    31. Salisu, Afees A. & Raheem, Ibrahim D. & Vo, Xuan Vinh, 2021. "Assessing the safe haven property of the gold market during COVID-19 pandemic," International Review of Financial Analysis, Elsevier, vol. 74(C).
    32. Mokni, Khaled & Youssef, Manel & Ajmi, Ahdi Noomen, 2022. "COVID-19 pandemic and economic policy uncertainty: The first test on the hedging and safe haven properties of cryptocurrencies," Research in International Business and Finance, Elsevier, vol. 60(C).
    33. Dickey, David A & Fuller, Wayne A, 1981. "Likelihood Ratio Statistics for Autoregressive Time Series with a Unit Root," Econometrica, Econometric Society, vol. 49(4), pages 1057-1072, June.
    34. Fang, Yi & Shao, Zhiquan, 2022. "The Russia-Ukraine conflict and volatility risk of commodity markets," Finance Research Letters, Elsevier, vol. 50(C).
    35. Conlon, Thomas & McGee, Richard, 2020. "Safe haven or risky hazard? Bitcoin during the Covid-19 bear market," Finance Research Letters, Elsevier, vol. 35(C).
    36. Pesaran, M Hashem, 1997. "The Role of Economic Theory in Modelling the Long Run," Economic Journal, Royal Economic Society, vol. 107(440), pages 178-191, January.
    37. Lucey, Brian M. & Vigne, Samuel A. & Yarovaya, Larisa & Wang, Yizhi, 2022. "The cryptocurrency uncertainty index," Finance Research Letters, Elsevier, vol. 45(C).
    38. Bhuiyan, Rubaiyat Ahsan & Husain, Afzol & Zhang, Changyong, 2021. "A wavelet approach for causal relationship between bitcoin and conventional asset classes," Resources Policy, Elsevier, vol. 71(C).
    39. Cheah, Eng-Tuck & Fry, John, 2015. "Speculative bubbles in Bitcoin markets? An empirical investigation into the fundamental value of Bitcoin," Economics Letters, Elsevier, vol. 130(C), pages 32-36.
    40. Yoshino, Naoyuki & Taghizadeh-Hesary, Farhad & Otsuka, Miyu, 2021. "Covid-19 and Optimal Portfolio Selection for Investment in Sustainable Development Goals," Finance Research Letters, Elsevier, vol. 38(C).
    41. Będowska-Sójka, Barbara & Kliber, Agata, 2021. "Is there one safe-haven for various turbulences? The evidence from gold, Bitcoin and Ether," The North American Journal of Economics and Finance, Elsevier, vol. 56(C).
    42. Baur, Dirk G. & Dimpfl, Thomas & Kuck, Konstantin, 2018. "Bitcoin, gold and the US dollar – A replication and extension," Finance Research Letters, Elsevier, vol. 25(C), pages 103-110.
    43. Elie Bouri & Naji Jalkh & Peter Molnár & David Roubaud, 2017. "Bitcoin for energy commodities before and after the December 2013 crash: diversifier, hedge or safe haven?," Applied Economics, Taylor & Francis Journals, vol. 49(50), pages 5063-5073, October.
    44. Gil-Alana, Luis Alberiko & Abakah, Emmanuel Joel Aikins & Rojo, María Fátima Romero, 2020. "Cryptocurrencies and stock market indices. Are they related?," Research in International Business and Finance, Elsevier, vol. 51(C).
    45. Conlon, Thomas & Corbet, Shaen & McGee, Richard J., 2020. "Are cryptocurrencies a safe haven for equity markets? An international perspective from the COVID-19 pandemic," Research in International Business and Finance, Elsevier, vol. 54(C).
    46. Yousaf, Imran & Patel, Ritesh & Yarovaya, Larisa, 2022. "The reaction of G20+ stock markets to the Russia–Ukraine conflict “black-swan” event: Evidence from event study approach," Journal of Behavioral and Experimental Finance, Elsevier, vol. 35(C).
    47. Esfandiar Maasoumi & Xi Wu, 2021. "Contrasting Cryptocurrencies with Other Assets: Full Distributions and the COVID Impact," JRFM, MDPI, vol. 14(9), pages 1-15, September.
    48. Ren, Xiaohang & Wang, Rui & Duan, Kun & Chen, Jinyu, 2022. "Dynamics of the sheltering role of Bitcoin against crude oil market crash with varying severity of the COVID-19: A comparison with gold," Research in International Business and Finance, Elsevier, vol. 62(C).
    49. Al-Yahyaee, Khamis Hamed & Mensi, Walid & Sensoy, Ahmet & Kang, Sang Hoon, 2019. "Energy, precious metals, and GCC stock markets: Is there any risk spillover?," Pacific-Basin Finance Journal, Elsevier, vol. 56(C), pages 45-70.
    50. Mensi, Walid & Hammoudeh, Shawkat & Tiwari, Aviral Kumar, 2016. "New evidence on hedges and safe havens for Gulf stock markets using the wavelet-based quantile," Emerging Markets Review, Elsevier, vol. 28(C), pages 155-183.
    51. Dyhrberg, Anne Haubo, 2016. "Hedging capabilities of bitcoin. Is it the virtual gold?," Finance Research Letters, Elsevier, vol. 16(C), pages 139-144.
    52. Rizvi, Syed Kumail Abbas & Naqvi, Bushra & Mirza, Nawazish & Umar, Muhammad, 2022. "Safe haven properties of green, Islamic, and crypto assets and investor's proclivity towards treasury and gold," Energy Economics, Elsevier, vol. 115(C).
    53. Zhang, Dayong, 2017. "Oil shocks and stock markets revisited: Measuring connectedness from a global perspective," Energy Economics, Elsevier, vol. 62(C), pages 323-333.
    54. Wang, Pengfei & Zhang, Wei & Li, Xiao & Shen, Dehua, 2019. "Is cryptocurrency a hedge or a safe haven for international indices? A comprehensive and dynamic perspective," Finance Research Letters, Elsevier, vol. 31(C), pages 1-18.
    55. Ji, Qiang & Zhang, Dayong & Zhao, Yuqian, 2020. "Searching for safe-haven assets during the COVID-19 pandemic," International Review of Financial Analysis, Elsevier, vol. 71(C).
    56. Shahzad, Syed Jawad Hussain & Bouri, Elie & Roubaud, David & Kristoufek, Ladislav & Lucey, Brian, 2019. "Is Bitcoin a better safe-haven investment than gold and commodities?," International Review of Financial Analysis, Elsevier, vol. 63(C), pages 322-330.
    57. Lahiani, Amine & Mefteh-Wali, Salma & Vasbieva, Dinara G., 2021. "The safe-haven property of precious metal commodities in the COVID-19 era," Resources Policy, Elsevier, vol. 74(C).
    58. Baur, Dirk G. & Hong, KiHoon & Lee, Adrian D., 2018. "Bitcoin: Medium of exchange or speculative assets?," Journal of International Financial Markets, Institutions and Money, Elsevier, vol. 54(C), pages 177-189.
    59. Corbet, Shaen & Hou, Yang (Greg) & Hu, Yang & Larkin, Charles & Oxley, Les, 2020. "Any port in a storm: Cryptocurrency safe-havens during the COVID-19 pandemic," Economics Letters, Elsevier, vol. 194(C).
    60. Maghyereh, Aktham I. & Awartani, Basel & Tziogkidis, Panagiotis, 2017. "Volatility spillovers and cross-hedging between gold, oil and equities: Evidence from the Gulf Cooperation Council countries," Energy Economics, Elsevier, vol. 68(C), pages 440-453.
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    More about this item

    Keywords

    Asymmetry; Bonds; Bitcoin; Commodities; COVID-19 pandemic; Russia–Ukraine war;
    All these keywords.

    JEL classification:

    • G11 - Financial Economics - - General Financial Markets - - - Portfolio Choice; Investment Decisions
    • G12 - Financial Economics - - General Financial Markets - - - Asset Pricing; Trading Volume; Bond Interest Rates
    • F65 - International Economics - - Economic Impacts of Globalization - - - Finance

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