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Safe Havens, Machine Learning, and the Sources of Geopolitical Risk: A Forecasting Analysis Using Over a Century of Data

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  • Rangan Gupta

    (University of Pretoria)

  • Sayar Karmakar

    (University of Florida)

  • Christian Pierdzioch

    (Helmut Schmidt University)

Abstract

We use monthly data covering a century-long sample period (1915–2021) to study whether geopolitical risk helps to forecast subsequent gold volatility. We account not only for geopolitical threats and acts, but also for 39 country-specific sources of geopolitical risk. The response of subsequent volatility is heterogeneous across countries and nonlinear. We find that accounting for geopolitical risk at the country level improves forecast accuracy, especially when we use random forests to estimate our forecasting models. As an extension, we report empirical evidence on the predictive value of the country-level sources of geopolitical risk for two other candidate safe-haven assets, oil and silver, over the sample periods 1900–2021 and 1915–2021, respectively. Our results have important implications for the portfolio and risk-management decisions of investors who seek a safe haven in times of heightened geopolitical tensions.

Suggested Citation

  • Rangan Gupta & Sayar Karmakar & Christian Pierdzioch, 2024. "Safe Havens, Machine Learning, and the Sources of Geopolitical Risk: A Forecasting Analysis Using Over a Century of Data," Computational Economics, Springer;Society for Computational Economics, vol. 64(1), pages 487-513, July.
  • Handle: RePEc:kap:compec:v:64:y:2024:i:1:d:10.1007_s10614-023-10452-w
    DOI: 10.1007/s10614-023-10452-w
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    1. Reboredo, Juan C., 2013. "Is gold a safe haven or a hedge for the US dollar? Implications for risk management," Journal of Banking & Finance, Elsevier, vol. 37(8), pages 2665-2676.
    2. Bouri, Elie & Cepni, Oguzhan & Gabauer, David & Gupta, Rangan, 2021. "Return connectedness across asset classes around the COVID-19 outbreak," International Review of Financial Analysis, Elsevier, vol. 73(C).
    3. Aye, Goodness & Gupta, Rangan & Hammoudeh, Shawkat & Kim, Won Joong, 2015. "Forecasting the price of gold using dynamic model averaging," International Review of Financial Analysis, Elsevier, vol. 41(C), pages 257-266.
    4. Bonato, Matteo & Demirer, Riza & Gupta, Rangan & Pierdzioch, Christian, 2018. "Gold futures returns and realized moments: A forecasting experiment using a quantile-boosting approach," Resources Policy, Elsevier, vol. 57(C), pages 196-212.
    5. Elie Bouri & Riza Demirer & Rangan Gupta & Hardik A. Marfatia, 2019. "Geopolitical Risks and Movements in Islamic Bond and Equity Markets: A Note," Defence and Peace Economics, Taylor & Francis Journals, vol. 30(3), pages 367-379, April.
    6. Bouoiyour, Jamal & Selmi, Refk & Wohar, Mark E., 2018. "Measuring the response of gold prices to uncertainty: An analysis beyond the mean," Economic Modelling, Elsevier, vol. 75(C), pages 105-116.
    7. Plakandaras, Vasilios & Gupta, Rangan & Wong, Wing-Keung, 2019. "Point and density forecasts of oil returns: The role of geopolitical risks," Resources Policy, Elsevier, vol. 62(C), pages 580-587.
    8. 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.
    9. Salisu, Afees A. & Gupta, Rangan & Bouri, Elie & Ji, Qiang, 2020. "The role of global economic conditions in forecasting gold market volatility: Evidence from a GARCH-MIDAS approach," Research in International Business and Finance, Elsevier, vol. 54(C).
    10. John Y. Campbell, 2008. "Viewpoint: Estimating the equity premium," Canadian Journal of Economics/Revue canadienne d'économique, John Wiley & Sons, vol. 41(1), pages 1-21, February.
    11. Michele Piffer & Maximilian Podstawski, 2018. "Identifying Uncertainty Shocks Using the Price of Gold," Economic Journal, Royal Economic Society, vol. 128(616), pages 3266-3284, December.
    12. Dichtl, Hubert, 2020. "Forecasting excess returns of the gold market: Can we learn from stock market predictions?," Journal of Commodity Markets, Elsevier, vol. 19(C).
    13. 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.
    14. Christian Pierdzioch & Marian Risse & Sebastian Rohloff, 2015. "Forecasting gold-price fluctuations: a real-time boosting approach," Applied Economics Letters, Taylor & Francis Journals, vol. 22(1), pages 46-50, January.
    15. Hollstein, Fabian & Prokopczuk, Marcel & Tharann, Björn & Wese Simen, Chardin, 2021. "Predictability in commodity markets: Evidence from more than a century," Journal of Commodity Markets, Elsevier, vol. 24(C).
    16. Asai, Manabu & Gupta, Rangan & McAleer, Michael, 2020. "Forecasting volatility and co-volatility of crude oil and gold futures: Effects of leverage, jumps, spillovers, and geopolitical risks," International Journal of Forecasting, Elsevier, vol. 36(3), pages 933-948.
    17. Clark, Todd E. & West, Kenneth D., 2007. "Approximately normal tests for equal predictive accuracy in nested models," Journal of Econometrics, Elsevier, vol. 138(1), pages 291-311, May.
    18. Boubaker, Heni & Cunado, Juncal & Gil-Alana, Luis A. & Gupta, Rangan, 2020. "Global crises and gold as a safe haven: Evidence from over seven and a half centuries of data," Physica A: Statistical Mechanics and its Applications, Elsevier, vol. 540(C).
    19. Gozgor, Giray & Lau, Chi Keung Marco & Sheng, Xin & Yarovaya, Larisa, 2019. "The role of uncertainty measures on the returns of gold," Economics Letters, Elsevier, vol. 185(C).
    20. Joscha Beckmann & Theo Berger & Robert Czudaj, 2019. "Gold price dynamics and the role of uncertainty," Quantitative Finance, Taylor & Francis Journals, vol. 19(4), pages 663-681, April.
    21. Parisi, Antonino & Parisi, Franco & Díaz, David, 2008. "Forecasting gold price changes: Rolling and recursive neural network models," Journal of Multinational Financial Management, Elsevier, vol. 18(5), pages 477-487, December.
    22. Salisu, Afees A. & Gupta, Rangan & Karmakar, Sayar & Das, Sonali, 2022. "Forecasting output growth of advanced economies over eight centuries: The role of gold market volatility as a proxy of global uncertainty," Resources Policy, Elsevier, vol. 75(C).
    23. Hossein Hassani & Emmanuel Sirimal Silva & Rangan Gupta & Mawuli K. Segnon, 2015. "Forecasting the price of gold," Applied Economics, Taylor & Francis Journals, vol. 47(39), pages 4141-4152, August.
    24. Tiwari, Aviral Kumar & Aye, Goodness C. & Gupta, Rangan & Gkillas, Konstantinos, 2020. "Gold-oil dependence dynamics and the role of geopolitical risks: Evidence from a Markov-switching time-varying copula model," Energy Economics, Elsevier, vol. 88(C).
    25. Chak Hung Jack Cheng & Ching-Wai (Jeremy) Chiu, 2018. "How important are global geopolitical risks to emerging countries?," International Economics, CEPII research center, issue 156, pages 305-325.
    26. Pierdzioch, Christian & Risse, Marian & Rohloff, Sebastian, 2015. "A real-time quantile-regression approach to forecasting gold returns under asymmetric loss," Resources Policy, Elsevier, vol. 45(C), pages 299-306.
    27. Matthew W. Clance & Rangan Gupta & Mark E. Wohar, 2019. "Geopolitical risks and recessions in a panel of advanced economies: evidence from over a century of data," Applied Economics Letters, Taylor & Francis Journals, vol. 26(16), pages 1317-1321, September.
    28. Jie Chen & Dimitris N. Politis, 2019. "Optimal Multi-Step-Ahead Prediction of ARCH/GARCH Models and NoVaS Transformation," Econometrics, MDPI, vol. 7(3), pages 1-23, August.
    29. Sayar Karmakar & Stefan Richter & Wei Biao Wu, 2020. "Simultaneous inference for time-varying models," Papers 2011.13157, arXiv.org, revised Mar 2021.
    30. Baur, Dirk G. & Smales, Lee A., 2020. "Hedging geopolitical risk with precious metals," Journal of Banking & Finance, Elsevier, vol. 117(C).
    31. Balcilar, Mehmet & Bonato, Matteo & Demirer, Riza & Gupta, Rangan, 2018. "Geopolitical risks and stock market dynamics of the BRICS," Economic Systems, Elsevier, vol. 42(2), pages 295-306.
    32. Beckmann, Joscha & Berger, Theo & Czudaj, Robert, 2015. "Does gold act as a hedge or a safe haven for stocks? A smooth transition approach," Economic Modelling, Elsevier, vol. 48(C), pages 16-24.
    33. Cepni, Oguzhan & Dul, Wiehan & Gupta, Rangan & Wohar, Mark E., 2021. "The dynamics of U.S. REITs returns to uncertainty shocks: A proxy SVAR approach," Research in International Business and Finance, Elsevier, vol. 58(C).
    34. Gupta, Rangan & Majumdar, Anandamayee & Pierdzioch, Christian & Wohar, Mark E., 2017. "Do terror attacks predict gold returns? Evidence from a quantile-predictive-regression approach," The Quarterly Review of Economics and Finance, Elsevier, vol. 65(C), pages 276-284.
    35. Balcilar, Mehmet & Gupta, Rangan & Pierdzioch, Christian, 2016. "Does uncertainty move the gold price? New evidence from a nonparametric causality-in-quantiles test," Resources Policy, Elsevier, vol. 49(C), pages 74-80.
    36. Nguyen, Duc Binh Benno & Prokopczuk, Marcel & Wese Simen, Chardin, 2019. "The risk premium of gold," Journal of International Money and Finance, Elsevier, vol. 94(C), pages 140-159.
    37. Salisu, Afees A. & Cuñado, Juncal & Gupta, Rangan, 2022. "Geopolitical risks and historical exchange rate volatility of the BRICS," International Review of Economics & Finance, Elsevier, vol. 77(C), pages 179-190.
    38. Luo, Jiawen & Demirer, Riza & Gupta, Rangan & Ji, Qiang, 2022. "Forecasting oil and gold volatilities with sentiment indicators under structural breaks," Energy Economics, Elsevier, vol. 105(C).
    39. Pierdzioch, Christian & Risse, Marian & Rohloff, Sebastian, 2014. "The international business cycle and gold-price fluctuations," The Quarterly Review of Economics and Finance, Elsevier, vol. 54(2), pages 292-305.
    40. Balcilar, Mehmet & Bonato, Matteo & Demirer, Riza & Gupta, Rangan, 2017. "The effect of investor sentiment on gold market return dynamics: Evidence from a nonparametric causality-in-quantiles approach," Resources Policy, Elsevier, vol. 51(C), pages 77-84.
    41. Mei, Dexiang & Ma, Feng & Liao, Yin & Wang, Lu, 2020. "Geopolitical risk uncertainty and oil future volatility: Evidence from MIDAS models," Energy Economics, Elsevier, vol. 86(C).
    42. Diebold, Francis X & Mariano, Roberto S, 2002. "Comparing Predictive Accuracy," Journal of Business & Economic Statistics, American Statistical Association, vol. 20(1), pages 134-144, January.
    43. Friedman, Jerome H. & Hastie, Trevor & Tibshirani, Rob, 2010. "Regularization Paths for Generalized Linear Models via Coordinate Descent," Journal of Statistical Software, Foundation for Open Access Statistics, vol. 33(i01).
    44. Pierdzioch, Christian & Risse, Marian & Rohloff, Sebastian, 2016. "A quantile-boosting approach to forecasting gold returns," The North American Journal of Economics and Finance, Elsevier, vol. 35(C), pages 38-55.
    45. Liu, Jing & Ma, Feng & Tang, Yingkai & Zhang, Yaojie, 2019. "Geopolitical risk and oil volatility: A new insight," Energy Economics, Elsevier, vol. 84(C).
    46. John Y. Campbell, 2007. "Estimating the Equity Premium," NBER Working Papers 13423, National Bureau of Economic Research, Inc.
    47. Gkillas, Konstantinos & Gupta, Rangan & Pierdzioch, Christian, 2020. "Forecasting realized gold volatility: Is there a role of geopolitical risks?," Finance Research Letters, Elsevier, vol. 35(C).
    48. Balcilar, Mehmet & Demirer, Riza & Gupta, Rangan & Wohar, Mark E., 2020. "The effect of global and regional stock market shocks on safe haven assets," Structural Change and Economic Dynamics, Elsevier, vol. 54(C), pages 297-308.
    49. Salisu, Afees A. & Pierdzioch, Christian & Gupta, Rangan, 2021. "Geopolitical risk and forecastability of tail risk in the oil market: Evidence from over a century of monthly data," Energy, Elsevier, vol. 235(C).
    50. Menglong Yang & Qiang Zhang & Adan Yi & Peng Peng & Baogui Xin, 2021. "Geopolitical Risk and Stock Market Volatility in Emerging Economies: Evidence from GARCH-MIDAS Model," Discrete Dynamics in Nature and Society, Hindawi, vol. 2021, pages 1-17, September.
    51. Low, Rand Kwong Yew & Yao, Yiran & Faff, Robert, 2016. "Diamonds vs. precious metals: What shines brightest in your investment portfolio?," International Review of Financial Analysis, Elsevier, vol. 43(C), pages 1-14.
    52. Bouoiyour, Jamal & Selmi, Refk & Hammoudeh, Shawkat & Wohar, Mark E., 2019. "What are the categories of geopolitical risks that could drive oil prices higher? Acts or threats?," Energy Economics, Elsevier, vol. 84(C).
    53. Kejin Wu & Sayar Karmakar, 2021. "Model-Free Time-Aggregated Predictions for Econometric Datasets," Forecasting, MDPI, vol. 3(4), pages 1-14, December.
    54. Malliaris, A.G. & Malliaris, Mary, 2015. "What drives gold returns? A decision tree analysis," Finance Research Letters, Elsevier, vol. 13(C), pages 45-53.
    55. Sharma, Susan Sunila, 2016. "Can consumer price index predict gold price returns?," Economic Modelling, Elsevier, vol. 55(C), pages 269-278.
    56. Rangan Gupta & Anandamayee Majumdar & Jacobus Nel & Sowmya Subramaniam, 2021. "Geopolitical Risks And The High-Frequency Movements Of The Us Term Structure Of Interest Rates," Annals of Financial Economics (AFE), World Scientific Publishing Co. Pte. Ltd., vol. 16(03), pages 1-16, September.
    57. Boying Li & Chun-Ping Chang & Yin Chu & Bo Sui, 2020. "Oil prices and geopolitical risks: What implications are offered via multi-domain investigations?," Energy & Environment, , vol. 31(3), pages 492-516, May.
    58. Pierdzioch, Christian & Risse, Marian & Rohloff, Sebastian, 2016. "A boosting approach to forecasting the volatility of gold-price fluctuations under flexible loss," Resources Policy, Elsevier, vol. 47(C), pages 95-107.
    59. Agyei-Ampomah, Sam & Gounopoulos, Dimitrios & Mazouz, Khelifa, 2014. "Does gold offer a better protection against losses in sovereign debt bonds than other metals?," Journal of Banking & Finance, Elsevier, vol. 40(C), pages 507-521.
    60. Rapach, David & Zhou, Guofu, 2013. "Forecasting Stock Returns," Handbook of Economic Forecasting, in: G. Elliott & C. Granger & A. Timmermann (ed.), Handbook of Economic Forecasting, edition 1, volume 2, chapter 0, pages 328-383, Elsevier.
    61. Reboredo, Juan C., 2013. "Is gold a hedge or safe haven against oil price movements?," Resources Policy, Elsevier, vol. 38(2), pages 130-137.
    62. Harvey, David & Leybourne, Stephen & Newbold, Paul, 1997. "Testing the equality of prediction mean squared errors," International Journal of Forecasting, Elsevier, vol. 13(2), pages 281-291, June.
    63. Zhijing Ding & Xu Zhang & Baogui Xin, 2021. "The Impact of Geopolitical Risk on Systemic Risk Spillover in Commodity Market: An EMD-Based Network Topology Approach," Complexity, Hindawi, vol. 2021, pages 1-17, July.
    64. Elie Bouri & Oguzhan Cepni & Rangan Gupta & Naji Jalkh, 2020. "Geopolitical Risks and Stock Market Volatility in the G7 Countries: A Century of Evidence from a Time-Varying Nonparametric Panel Data Model," Working Papers 202029, University of Pretoria, Department of Economics.
    65. Qin, Yun & Hong, Kairong & Chen, Jinyu & Zhang, Zitao, 2020. "Asymmetric effects of geopolitical risks on energy returns and volatility under different market conditions," Energy Economics, Elsevier, vol. 90(C).
    66. Christian Pierdzioch & Marian Risse, 2020. "Forecasting precious metal returns with multivariate random forests," Empirical Economics, Springer, vol. 58(3), pages 1167-1184, March.
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    More about this item

    Keywords

    Gold; Geopolitical risk; Forecasting; Returns; Volatility; Random forests;
    All these keywords.

    JEL classification:

    • C22 - Mathematical and Quantitative Methods - - Single Equation Models; Single Variables - - - Time-Series Models; Dynamic Quantile Regressions; Dynamic Treatment Effect Models; Diffusion Processes
    • D80 - Microeconomics - - Information, Knowledge, and Uncertainty - - - General
    • H56 - Public Economics - - National Government Expenditures and Related Policies - - - National Security and War
    • Q02 - Agricultural and Natural Resource Economics; Environmental and Ecological Economics - - General - - - Commodity Market

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