{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,30]],"date-time":"2026-06-30T04:29:14Z","timestamp":1782793754872,"version":"3.54.5"},"reference-count":67,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2023,12,5]],"date-time":"2023-12-05T00:00:00Z","timestamp":1701734400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Entropy"],"abstract":"<jats:p>The COVID-19 pandemic has had an unprecedented impact on the global economy and financial markets. In this article, we explore the impact of the pandemic on the weak-form efficiency of the cryptocurrency and forex markets by conducting a comprehensive comparative analysis of the two markets. To estimate the weak-form of market efficiency, we utilize the asymmetric market deficiency measure (MDM) derived using the asymmetric multifractal detrended fluctuation analysis (A-MF-DFA) approach, along with fuzzy entropy, Tsallis entropy, and Fisher information. Initially, we analyze the temporal evolution of these four measures using overlapping sliding windows. Subsequently, we assess both the mean value and variance of the distribution for each measure and currency in two distinct time periods: before and during the pandemic. Our findings reveal distinct shifts in efficiency before and during the COVID-19 pandemic. Specifically, there was a clear increase in the weak-form inefficiency of traditional currencies during the pandemic. Among cryptocurrencies, BTC stands out for its behavior, which resembles that of traditional currencies. Moreover, our results underscore the significant impact of COVID-19 on weak-form market efficiency during both upward and downward market movements. These findings could be useful for investors, portfolio managers, and policy makers.<\/jats:p>","DOI":"10.3390\/e25121622","type":"journal-article","created":{"date-parts":[[2023,12,5]],"date-time":"2023-12-05T08:09:17Z","timestamp":1701763757000},"page":"1622","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["The Impact of COVID-19 on Weak-Form Efficiency in Cryptocurrency and Forex Markets"],"prefix":"10.3390","volume":"25","author":[{"given":"Pavlos I.","family":"Zitis","sequence":"first","affiliation":[{"name":"Department of Electrical and Electronics Engineering, University of West Attica, Ancient Olive Grove Campus, Egaleo, 12241 Athens, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0256-1819","authenticated-orcid":false,"given":"Shinji","family":"Kakinaka","sequence":"additional","affiliation":[{"name":"Department of Applied Mathematics and Physics, Graduate School of Informatics, Kyoto University, Sakyo, Kyoto 606-8501, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9162-1261","authenticated-orcid":false,"given":"Ken","family":"Umeno","sequence":"additional","affiliation":[{"name":"Department of Applied Mathematics and Physics, Graduate School of Informatics, Kyoto University, Sakyo, Kyoto 606-8501, Japan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8484-1402","authenticated-orcid":false,"given":"Stavros G.","family":"Stavrinides","sequence":"additional","affiliation":[{"name":"Department of Physics, International Hellenic University, 65404 Kavala, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0918-9343","authenticated-orcid":false,"given":"Michael P.","family":"Hanias","sequence":"additional","affiliation":[{"name":"Department of Physics, International Hellenic University, 65404 Kavala, Greece"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5928-4587","authenticated-orcid":false,"given":"Stelios M.","family":"Potirakis","sequence":"additional","affiliation":[{"name":"Department of Electrical and Electronics Engineering, University of West Attica, Ancient Olive Grove Campus, Egaleo, 12241 Athens, Greece"},{"name":"National Observatory of Athens, Metaxa and Vasileos Pavlou, Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing, Penteli, 15236 Athens, Greece"},{"name":"Department of Electrical Engineering, Computer Engineering and Informatics, School of Engineering, Frederick University, Nicosia 1036, Cyprus"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2023,12,5]]},"reference":[{"key":"ref_1","unstructured":"Bachelier, L. (1990). Th\u00e9orie de la Speculation, Annales Scientifiques de I.E.N.S., Soci\u00e9t\u00e9 Math\u00e9matique de France."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"383","DOI":"10.2307\/2325486","article-title":"Efficient Capital Markets: A Review of Theory and Empirical Work","volume":"25","author":"Fama","year":"1970","journal-title":"J. Financ."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"442","DOI":"10.1016\/S2212-5671(15)01416-1","article-title":"The Efficient Market Hypothesis: Review of Specialized Literature and Empirical Research","volume":"32","year":"2015","journal-title":"Procedia Econ. Financ."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"15","DOI":"10.3905\/jpm.2004.442611","article-title":"The Adaptive Markets Hypothesis","volume":"30","author":"Lo","year":"2004","journal-title":"J. Portf. Manag."},{"key":"ref_5","unstructured":"Peters, E.E. (1994). Fractal Market Analysis: Applying Chaos Theory to Investment and Economics, Wiley."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"2857","DOI":"10.1038\/srep02857","article-title":"Fractal Markets Hypothesis and the Global Financial Crisis: Wavelet Power Evidence","volume":"3","author":"Kristoufek","year":"2013","journal-title":"Sci. Rep."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"289","DOI":"10.1016\/S0960-0779(98)00295-1","article-title":"Fractal Market Hypothesis and Two Power-Laws","volume":"11","author":"Weron","year":"2000","journal-title":"Chaos Solitons Fractals"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"297","DOI":"10.1093\/biomet\/65.2.297","article-title":"On a Measure of Lack of Fit in Time Series Models","volume":"65","author":"Ljung","year":"1978","journal-title":"Biometrika"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"147","DOI":"10.1214\/aoms\/1177731909","article-title":"On a Test Whether Two Samples Are from the Same Population","volume":"11","author":"Wald","year":"1940","journal-title":"Ann. Math. Stat."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"40","DOI":"10.1080\/01621459.1982.10477764","article-title":"The Rank Version of von Neumann\u2019s Ratio Test for Randomness","volume":"77","author":"Bartels","year":"1982","journal-title":"J. Am. Stat. Assoc."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"179","DOI":"10.1016\/j.frl.2009.04.003","article-title":"Automatic Variance Ratio Test under Conditional Heteroskedasticity","volume":"6","author":"Kim","year":"2009","journal-title":"Financ. Res. Lett."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"355","DOI":"10.1016\/0304-4076(91)90025-9","article-title":"Spectral Based Testing of the Martingale Hypothesis","volume":"50","author":"Durlauf","year":"1991","journal-title":"J. Econom."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"293","DOI":"10.1002\/(SICI)1099-1255(199905\/06)14:3<293::AID-JAE503>3.0.CO;2-5","article-title":"Testing the Random Walk Hypothesis for Real Exchange Rates","volume":"14","author":"Choi","year":"1999","journal-title":"J. Appl. Econom."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"197","DOI":"10.1080\/07474939608800353","article-title":"A Test for Independence Based on the Correlation Dimension","volume":"15","author":"Broock","year":"1996","journal-title":"Econom. Rev."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"140","DOI":"10.1016\/j.jeconom.2009.03.001","article-title":"An Automatic Portmanteau Test for Serial Correlation","volume":"151","author":"Escanciano","year":"2009","journal-title":"J. Econom."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"151","DOI":"10.1016\/j.jeconom.2005.06.019","article-title":"Generalized Spectral Tests for the Martingale Difference Hypothesis","volume":"134","author":"Escanciano","year":"2006","journal-title":"J. Econom."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"575","DOI":"10.1111\/j.1468-0262.2006.00758.x","article-title":"Efficient Wald Tests for Fractional Unit Roots","volume":"75","author":"Lobato","year":"2007","journal-title":"Econometrica"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"1279","DOI":"10.2307\/2938368","article-title":"Long-Term Memory in Stock Market Prices","volume":"59","author":"Lo","year":"1991","journal-title":"Econometrica"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"141","DOI":"10.1016\/j.ribaf.2018.01.002","article-title":"Persistence in the Cryptocurrency Market","volume":"46","author":"Caporale","year":"2018","journal-title":"Res. Int. Bus. Financ."},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Zitis, P.I., Kakinaka, S., Umeno, K., Hanias, M.P., Stavrinides, S.G., and Potirakis, S.M. (2023). Investigating Dynamical Complexity and Fractal Characteristics of Bitcoin\/US Dollar and Euro\/US Dollar Exchange Rates around the COVID-19 Outbreak. Entropy, 25.","DOI":"10.3390\/e25020214"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"109936","DOI":"10.1016\/j.chaos.2020.109936","article-title":"The Impact of COVID-19 Pandemic upon Stability and Sequential Irregularity of Equity and Cryptocurrency Markets","volume":"138","author":"Lahmiri","year":"2020","journal-title":"Chaos Solitons Fractals"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"2340003","DOI":"10.1142\/S0219477523400035","article-title":"Comparing the Efficiency and Similarity between WTI, Fiat Currencies and Foreign Exchange Rates","volume":"22","author":"Fernandes","year":"2022","journal-title":"Fluct. Noise Lett."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"101888","DOI":"10.1016\/j.frl.2020.101888","article-title":"COVID-19 and Financial Market Efficiency: Evidence from an Entropy-Based Analysis","volume":"42","author":"Wang","year":"2021","journal-title":"Financ. Res. Lett."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"101851","DOI":"10.1016\/j.frl.2020.101851","article-title":"Fractal Analysis of Market (In)Efficiency during the COVID-19","volume":"38","author":"Frezza","year":"2020","journal-title":"Financ. Res. Lett."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"101647","DOI":"10.1016\/j.frl.2020.101647","article-title":"How the Cryptocurrency Market Has Performed during COVID-19? A Multifractal Analysis","volume":"36","author":"Mnif","year":"2020","journal-title":"Financ. Res. Lett."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"120261","DOI":"10.1016\/j.techfore.2020.120261","article-title":"On the Efficiency of Foreign Exchange Markets in Times of the COVID-19 Pandemic","volume":"161","author":"Aslam","year":"2020","journal-title":"Technol. Forecast. Soc. Chang."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"125562","DOI":"10.1016\/j.physa.2020.125562","article-title":"Asymmetric Efficiency of Cryptocurrencies during COVID-19","volume":"565","author":"Naeem","year":"2021","journal-title":"Phys. A Stat. Mech. Its Appl."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"102319","DOI":"10.1016\/j.frl.2021.102319","article-title":"Cryptocurrency Market Efficiency in Short- and Long-Term Horizons during COVID-19: An Asymmetric Multifractal Analysis Approach","volume":"46","author":"Kakinaka","year":"2022","journal-title":"Financ. Res. Lett."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"101773","DOI":"10.1016\/j.najef.2022.101773","article-title":"Pricing Efficiency and Asymmetric Multifractality of Major Asset Classes before and during COVID-19 Crisis","volume":"62","author":"Mensi","year":"2022","journal-title":"N. Am. J. Econ. Financ."},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Dro\u017cd\u017c, S., Kwapie\u0144, J., O\u015bwi\u0119cimka, P., Stanisz, T., and W\u0105torek, M. (2020). Complexity in Economic and Social Systems: Cryptocurrency Market at around COVID-19. Entropy, 22.","DOI":"10.3390\/e22091043"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"112238","DOI":"10.1016\/j.chaos.2022.112238","article-title":"A Singular Value Decomposition Entropy Approach to Assess the Impact of COVID-19 on the Informational Efficiency of the WTI Crude Oil Market","volume":"160","author":"Rodriguez","year":"2022","journal-title":"Chaos Solitons Fractals"},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Almeida, D., Dion\u00edsio, A., Vieira, I., and Ferreira, P. (2023). COVID-19 Effects on the Relationship between Cryptocurrencies: Can It Be Contagion? Insights from Econophysics Approaches. Entropy, 25.","DOI":"10.3390\/e25010098"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"102368","DOI":"10.1016\/j.irfa.2022.102368","article-title":"Critical Dynamics Related to a Recent Bitcoin Crash","volume":"84","author":"Zitis","year":"2022","journal-title":"Int. Rev. Financ. Anal."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"101599","DOI":"10.1016\/j.pacfin.2021.101599","article-title":"Mutual Fund Herding and Return Comovement in Chinese Equities","volume":"68","author":"Caglayan","year":"2021","journal-title":"Pac. Basin Financ. J."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"12761","DOI":"10.1038\/s41598-019-49320-9","article-title":"Quantifying the Randomness of the Stock Markets","volume":"9","year":"2019","journal-title":"Sci. Rep."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"126121","DOI":"10.1016\/j.physa.2021.126121","article-title":"Dynamical Characteristics of Global Stock Markets Based on Time Dependent Tsallis Non-Extensive Statistics and Generalized Hurst Exponents","volume":"578","author":"Antoniades","year":"2021","journal-title":"Phys. A Stat. Mech. Its Appl."},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Dro\u017cd\u017c, S., Minati, L., O\u015bwi\u0229cimka, P., Stanuszek, M., and Wa\u0327torek, M. (2019). Signatures of the Crypto-Currency Market Decoupling from the Forex. Future Internet, 11.","DOI":"10.3390\/fi11070154"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"797","DOI":"10.1016\/j.physa.2012.10.042","article-title":"Asymmetric Multifractal Scaling Behavior in the Chinese Stock Market: Based on Asymmetric MF-DFA","volume":"392","author":"Cao","year":"2013","journal-title":"Phys. A Stat. Mech. Its Appl."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"19","DOI":"10.1016\/j.frl.2019.03.029","article-title":"Intraday Downward\/Upward Multifractality and Long Memory in Bitcoin and Ethereum Markets: An Asymmetric Multifractal Detrended Fluctuation Analysis","volume":"31","author":"Mensi","year":"2019","journal-title":"Financ. Res. Lett."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"271","DOI":"10.1016\/j.irfa.2009.09.005","article-title":"Analysis of Efficiency for Shenzhen Stock Market Based on Multifractal Detrended Fluctuation Analysis","volume":"18","author":"Wang","year":"2009","journal-title":"Int. Rev. Financ. Anal."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"101077","DOI":"10.1016\/j.frl.2018.12.025","article-title":"Adaptive Long Memory in Volatility of Intra-Day Bitcoin Returns and the Impact of Trading Volume","volume":"32","author":"Khuntia","year":"2020","journal-title":"Financ. Res. Lett."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"86","DOI":"10.1016\/j.physa.2014.03.091","article-title":"An Analysis of Stock Market Efficiency: Developed vs. Islamic Stock Markets Using MF-DFA","volume":"407","author":"Rizvi","year":"2014","journal-title":"Phys. A Stat. Mech. Its Appl."},{"key":"ref_43","doi-asserted-by":"crossref","unstructured":"Vaz, C., Pascoal, R., and Sebasti\u00e3o, H. (2021). Price Appreciation and Roughness Duality in Bitcoin: A Multifractal Analysis. Mathematics, 9.","DOI":"10.3390\/math9172088"},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"266","DOI":"10.1109\/TNSRE.2007.897025","article-title":"Characterization of surface EMG signal based on fuzzy entropy","volume":"15","author":"Chen","year":"2007","journal-title":"IEEE Trans. Neural Syst. Rehabil. Eng."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"61","DOI":"10.1016\/j.medengphy.2008.04.005","article-title":"Measuring complexity using FuzzyEn, ApEn, and SampEn","volume":"31","author":"Chen","year":"2009","journal-title":"Med. Eng. Phys."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"4844","DOI":"10.3390\/e15114844","article-title":"Statistical Mechanics and Information-Theoretic Perspectives on Complexity in the Earth System","volume":"15","author":"Balasis","year":"2013","journal-title":"Entropy"},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"59","DOI":"10.1016\/j.ijsolstr.2017.09.005","article-title":"Experimental Study of the Dynamic Evolution of Cumulative Energy Release during LiF Fracture under Uniaxial Compression","volume":"132","author":"Mastrogiannis","year":"2018","journal-title":"Int. J. Solids Struct."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"479","DOI":"10.1007\/BF01016429","article-title":"Possible generalization of Boltzmann-Gibbs statistics","volume":"52","author":"Tsallis","year":"1988","journal-title":"J. Stat. Phys."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"1442","DOI":"10.1103\/PhysRevE.58.1442","article-title":"Generalized entropy-based criterion for consistent testing","volume":"58","author":"Tsallis","year":"1998","journal-title":"Phys. Rev. E"},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"6057","DOI":"10.1016\/j.physa.2008.07.004","article-title":"Fractional Brownian Motion, Fractional Gaussian Noise, and Tsallis Permutation Entropy","volume":"387","author":"Zunino","year":"2008","journal-title":"Phys. A Stat. Mech. Its Appl."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"2940","DOI":"10.1016\/j.physa.2013.03.006","article-title":"Dynamical Analogy between Economical Crisis and Earthquake Dynamics within the Nonextensive Statistical Mechanics Framework","volume":"392","author":"Potirakis","year":"2013","journal-title":"Phys. A Stat. Mech. Its Appl."},{"key":"ref_52","unstructured":"Fisher, R.A. (1925). Mathematical Proceedings of the Cambridge Philosophical Society, Cambridge University Press."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"300","DOI":"10.1016\/j.physa.2011.08.003","article-title":"Analysis of Electromagnetic Pre-Seismic Emissions Using Fisher Information and Tsallis Entropy","volume":"391","author":"Potirakis","year":"2012","journal-title":"Phys. A Stat. Mech. Its Appl."},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"5648","DOI":"10.1016\/j.physa.2012.04.030","article-title":"The Role of Propagating Stress Waves on a Geophysical Scale: Evidence in Terms of Nonextensivity","volume":"391","author":"Minadakis","year":"2012","journal-title":"Phys. A Stat. Mech. Its Appl."},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"4387","DOI":"10.1016\/j.physa.2008.02.064","article-title":"The Fisher Information Measure and Shannon Entropy for Particulate Matter Measurements","volume":"387","author":"Telesca","year":"2008","journal-title":"Phys. A Stat. Mech. Its Appl."},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"33","DOI":"10.1007\/s11270-008-9924-4","article-title":"Analysis of Dynamics in Cd, Fe, and Pb in Particulate Matter by Using the Fisher\u2013Shannon Method","volume":"201","author":"Telesca","year":"2008","journal-title":"Water Air Soil Pollut."},{"key":"ref_57","doi-asserted-by":"crossref","first-page":"858","DOI":"10.2478\/s11600-011-0018-0","article-title":"Discriminating Quarry Blasts from Earthquakes in V\u00e9rtes Hills (Hungary) by Using the Fisher-Shannon Method","volume":"59","author":"Telesca","year":"2011","journal-title":"Acta Geophys."},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"5061","DOI":"10.1088\/0031-9155\/53\/18\/014","article-title":"Fisher Information and Shannon Entropy for On-Line Detection of Transient Signal High-Values in Laser Doppler Flowmetry Signals of Healthy Subjects","volume":"53","author":"Humeau","year":"2008","journal-title":"Phys. Med. Biol."},{"key":"ref_59","doi-asserted-by":"crossref","first-page":"2036","DOI":"10.1016\/j.physa.2009.01.035","article-title":"A Nonlinear Strategy to Reveal Seismic Precursory Signatures in Earthquake-Related Self-Potential Signals","volume":"388","author":"Telesca","year":"2009","journal-title":"Phys. A Stat. Mech. Its Appl."},{"key":"ref_60","doi-asserted-by":"crossref","first-page":"78","DOI":"10.1016\/j.jvolgeores.2010.06.010","article-title":"Time-Dependent Fisher Information Measure of Volcanic Tremor before the 5 April 2003 Paroxysm at Stromboli Volcano, Italy","volume":"195","author":"Telesca","year":"2010","journal-title":"J. Volcanol. Geotherm. Res."},{"key":"ref_61","doi-asserted-by":"crossref","first-page":"1064","DOI":"10.1119\/1.1308267","article-title":"Physics from Fisher Information: A Unification","volume":"68","author":"Frieden","year":"2000","journal-title":"Am. J. Phys."},{"key":"ref_62","doi-asserted-by":"crossref","first-page":"25","DOI":"10.1016\/j.ecolmodel.2003.12.045","article-title":"Exergy and Fisher Information as Ecological Indices","volume":"174","author":"Fath","year":"2004","journal-title":"Ecol. Model."},{"key":"ref_63","doi-asserted-by":"crossref","first-page":"101646","DOI":"10.1016\/j.intfin.2022.101646","article-title":"Do Birds of a Feather Flock Together? Evidence from Time-Varying Herding Behaviour of Bitcoin and Foreign Exchange Majors during COVID-19","volume":"80","author":"Mohamad","year":"2022","journal-title":"J. Int. Financ. Mark. Inst. Money"},{"key":"ref_64","unstructured":"Bank for International Settlements (2020, October 03). Foreign Exchange Turnover in April 2019. Available online: https:\/\/www.bis.org\/statistics\/rpfx19_fx.pdf."},{"key":"ref_65","doi-asserted-by":"crossref","unstructured":"W\u0105torek, M., Kwapie\u0144, J., and Dro\u017cd\u017c, S. (2023). Cryptocurrencies Are Becoming Part of the World Global Financial Market. Entropy, 25.","DOI":"10.3390\/e25020377"},{"key":"ref_66","doi-asserted-by":"crossref","first-page":"071101","DOI":"10.1063\/1.5036517","article-title":"Bitcoin Market Route to Maturity? Evidence from Return Fluctuations, Temporal Correlations and Multiscaling Effects","volume":"28","author":"Minati","year":"2018","journal-title":"Chaos Interdiscip. J. Nonlinear Sci."},{"key":"ref_67","doi-asserted-by":"crossref","unstructured":"Kyriazis, N.A. (2019). A Survey on Efficiency and Profitable Trading Opportunities in Cryptocurrency Markets. J. Risk Financ. Manag., 12.","DOI":"10.3390\/jrfm12020067"}],"container-title":["Entropy"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1099-4300\/25\/12\/1622\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T21:33:37Z","timestamp":1760132017000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1099-4300\/25\/12\/1622"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,12,5]]},"references-count":67,"journal-issue":{"issue":"12","published-online":{"date-parts":[[2023,12]]}},"alternative-id":["e25121622"],"URL":"https:\/\/doi.org\/10.3390\/e25121622","relation":{},"ISSN":["1099-4300"],"issn-type":[{"value":"1099-4300","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,12,5]]}}}