# The Impact of COVID-19 on Weak-Form Efficiency in Cryptocurrency and Forex Markets

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## Abstract

**:**

## 1. Introduction

## 2. Methods

#### 2.1. Asymmetric Multifractal Detrended Fluctuation Analysis (A-MF-DFA)

#### 2.2. Market Deficiency Measure (MDM)

#### 2.3. Fuzzy Entropy

#### 2.4. Tsallis Entropy

#### 2.5. Fisher Information Measure

## 3. Data

## 4. Results

## 5. Conclusions

## Author Contributions

## Funding

## Institutional Review Board Statement

## Data Availability Statement

## Conflicts of Interest

## Appendix A

**Figure A1.**Each heatmap displays one-sided t-test probability values. All statistical tests were conducted at a 5% significance level. In the heatmaps: orange color signifies acceptance of the null hypothesis. Green color indicates rejection of the null hypothesis. Blue color represents cases where the statistical test is not applicable due to the comparison of identical currencies. Specifically: (

**a**) Null hypothesis: the mean value of MDM before the pandemic for each currency on the Y-axis is greater than the mean value of MDM before the pandemic for each currency on the X-axis. (

**b**) Null hypothesis: the mean value of MDM during the pandemic for each currency on the Y-axis is greater than the mean value of MDM during the pandemic for each currency on the X-axis. (

**c**) Null hypothesis: the mean value of MDM before the pandemic for each currency on the Y-axis is greater than the mean value of MDM during the pandemic for each currency on the X-axis. (

**d**) Reverse null hypothesis: the mean value of MDM before the pandemic for each currency on the Y-axis is less than the mean value of MDM before the pandemic for each currency on the X-axis. (

**e**) Reverse null hypothesis: the mean value of MDM during the pandemic for each currency on the Y-axis is less than the mean value of MDM during the pandemic for each currency on the X-axis. (

**f**) Reverse null hypothesis: the mean value of MDM before the pandemic for each currency on the Y-axis is less than the mean value of MDM during the pandemic for each currency on the X-axis.

**Figure A2.**Each heatmap displays F-test probability values. All statistical tests were conducted at a 5% significance level. In the heatmaps: yellow color signifies acceptance of the null hypothesis, blue color indicates rejection of the null hypothesis, and black color represents cases where the statistical test is not applicable due to the comparison of identical currencies. Specifically: (

**a**) Null hypothesis: the variance of MDM before the pandemic for each currency on the Y-axis is greater than the variance of MDM before the pandemic for each currency on the X-axis. (

**b**) Null hypothesis: the variance of MDM during the pandemic for each currency on the Y-axis is greater than the variance of MDM during the pandemic for each currency on the X-axis. (

**c**) Null hypothesis: the variance of MDM before the pandemic for each currency on the Y-axis is greater than the variance of MDM during the pandemic for each currency on the X-axis. (

**d**) Reverse null hypothesis: the variance of MDM before the pandemic for each currency on the Y-axis is less than the variance of MDM before the pandemic for each currency on the X-axis. (

**e**) Reverse null hypothesis: the variance of MDM during the pandemic for each currency on the Y-axis is less than the variance of MDM during the pandemic for each currency on the X-axis. (

**f**) Reverse null hypothesis: the variance of MDM before the pandemic for each currency on the Y-axis is less than the variance of MDM during the pandemic for each currency on the X-axis.

**Figure A3.**Same as Figure A1, but for the upward market trend.

**Figure A4.**Same as Figure A2, but for the upward market trend.

**Figure A5.**Same as Figure A1, but for the downward market trend.

**Figure A6.**Same as Figure A2, but for the downward market trend.

**Figure A7.**Each heatmap displays one-sided t-test probability values. All statistical tests were conducted at a 5% significance level. In the heatmaps: orange color signifies acceptance of the null hypothesis, green color indicates rejection of the null hypothesis, and blue color represents cases where the statistical test is not applicable due to the comparison of identical currencies. Specifically: (

**a**) Null hypothesis: the mean value of fuzzy entropy before the pandemic for each currency on the Y-axis is greater than the mean value of fuzzy entropy before the pandemic for each currency on the X-axis. (

**b**) Null hypothesis: the mean value of fuzzy entropy during the pandemic for each currency on the Y-axis is greater than the mean value of fuzzy entropy during the pandemic for each currency on the X-axis. (

**c**) Null hypothesis: the mean value of fuzzy entropy before the pandemic for each currency on the Y-axis is greater than the mean value of fuzzy entropy during the pandemic for each currency on the X-axis. (

**d**) Reverse null hypothesis: the mean value of fuzzy entropy before the pandemic for each currency on the Y-axis is less than the mean value of fuzzy entropy before the pandemic for each currency on the X-axis. (

**e**) Reverse null hypothesis: the mean value of fuzzy entropy during the pandemic for each currency on the Y-axis is less than the mean value of fuzzy entropy during the pandemic for each currency on the X-axis. (

**f**) Reverse null hypothesis: the mean value of fuzzy entropy before the pandemic for each currency on the Y-axis is less than the mean value of fuzzy entropy during the pandemic for each currency on the X-axis.

**Figure A8.**Each heatmap displays F-test probability values. All statistical tests were conducted at a 5% significance level. In the heatmaps: yellow color signifies acceptance of the null hypothesis, blue color indicates rejection of the null hypothesis, and black color represents cases where the statistical test is not applicable due to the comparison of identical currencies. Specifically: (

**a**) Null hypothesis: the variance of fuzzy entropy before the pandemic for each currency on the Y-axis is greater than the variance of fuzzy entropy before the pandemic for each currency on the X-axis. (

**b**) Null hypothesis: the variance of fuzzy entropy during the pandemic for each currency on the Y-axis is greater than the variance of fuzzy entropy during the pandemic for each currency on the X-axis. (

**c**) Null hypothesis: he variance of fuzzy entropy before the pandemic for each currency on the Y-axis is greater than the variance of fuzzy entropy during the pandemic for each currency on the X-axis. (

**d**) Reverse null hypothesis: the variance of fuzzy entropy before the pandemic for each currency on the Y-axis is less than the variance of fuzzy entropy before the pandemic for each currency on the X-axis. (

**e**) Reverse null hypothesis: the variance of fuzzy entropy during the pandemic for each currency on the Y-axis is less than the variance of fuzzy entropy during the pandemic for each currency on the X-axis. (

**f**) Reverse null hypothesis: the variance of fuzzy entropy before the pandemic for each currency on the Y-axis is less than the variance of fuzzy entropy during the pandemic for each currency on the X-axis.

**Figure A9.**Each heatmap displays one-sided t-test probability values. All statistical tests were conducted at a 5% significance level. In the heatmaps: orange color signifies acceptance of the null hypothesis, green color indicates rejection of the null hypothesis, and blue color represents cases where the statistical test is not applicable due to the comparison of identical currencies. Specifically: (

**a**) Null hypothesis: the mean value of Tsallis entropy before the pandemic for each currency on the Y-axis is greater than the mean value of Tsallis entropy before the pandemic for each currency on the X-axis. (

**b**) Null hypothesis: the mean value of Tsallis entropy during the pandemic for each currency on the Y-axis is greater than the mean value of Tsallis entropy during the pandemic for each currency on the X-axis. (

**c**) Null hypothesis: the mean value of Tsallis entropy before the pandemic for each currency on the Y-axis is greater than the mean value of Tsallis entropy during the pandemic for each currency on the X-axis. (

**d**) Reverse null hypothesis: the mean value of Tsallis entropy before the pandemic for each currency on the Y-axis is less than the mean value of Tsallis entropy before the pandemic for each currency on the X-axis. (

**e**) Reverse null hypothesis: the mean value of Tsallis entropy during the pandemic for each currency on the Y-axis is less than the mean value of Tsallis entropy during the pandemic for each currency on the X-axis. (

**f**) Reverse null hypothesis: the mean value of Tsallis entropy before the pandemic for each currency on the Y-axis is less than the mean value of Tsallis entropy during the pandemic for each currency on the X-axis.

**Figure A10.**Each heatmap displays F-test probability values. All statistical tests were conducted at a 5% significance level. In the heatmaps: yellow color signifies acceptance of the null hypothesis, blue color indicates rejection of the null hypothesis, and black color represents cases where the statistical test is not applicable due to the comparison of identical currencies. Specifically: (

**a**) Null hypothesis: the variance of Tsallis entropy before the pandemic for each currency on the Y-axis is greater than the variance of Tsallis entropy before the pandemic for each currency on the X-axis. (

**b**) Null hypothesis: the variance of Tsallis entropy during the pandemic for each currency on the Y-axis is greater than the variance of Tsallis entropy during the pandemic for each currency on the X-axis. (

**c**) Null hypothesis: the variance of Tsallis entropy before the pandemic for each currency on the Y-axis is greater than the variance of Tsallis entropy during the pandemic for each currency on the X-axis. (

**d**) Reverse null hypothesis: the variance of Tsallis entropy before the pandemic for each currency on the Y-axis is less than the variance of Tsallis entropy before the pandemic for each currency on the X-axis. (

**e**) Reverse null hypothesis: the variance of Tsallis entropy during the pandemic for each currency on the Y-axis is less than the variance of Tsallis entropy during the pandemic for each currency on the X-axis. (

**f**) Reverse null hypothesis: the variance of Tsallis entropy before the pandemic for each currency on the Y-axis is less than the variance of Tsallis entropy during the pandemic for each currency on the X-axis.

**Figure A11.**Each heatmap displays one-sided t-test probability values. All statistical tests were conducted at a 5% significance level. In the heatmaps: orange color signifies acceptance of the null hypothesis, green color indicates rejection of the null hypothesis, and blue color represents cases where the statistical test is not applicable due to the comparison of identical currencies. Specifically: (

**a**) Null hypothesis: the mean value of Fisher information before the pandemic for each currency on the Y-axis is greater than the mean value of Fisher information before the pandemic for each currency on the X-axis. (

**b**) Null hypothesis: the mean value of Fisher information during the pandemic for each currency on the Y-axis is greater than the mean value of Fisher information during the pandemic for each currency on the X-axis. (

**c**) Null hypothesis: the mean value of Fisher information before the pandemic for each currency on the Y-axis is greater than the mean value of Fisher information during the pandemic for each currency on the X-axis. (

**d**) Reverse null hypothesis: the mean value of Fisher information before the pandemic for each currency on the Y-axis is less than the mean value of Fisher information before the pandemic for each currency on the X-axis. (

**e**) Reverse null hypothesis: the mean value of Fisher information during the pandemic for each currency on the Y-axis is less than the mean value of Fisher information during the pandemic for each currency on the X-axis. (

**f**) Reverse null hypothesis: the mean value of Fisher information before the pandemic for each currency on the Y-axis is less than the mean value of Fisher information during the pandemic for each currency on the X-axis.

**Figure A12.**Each heatmap displays F-test probability values. All statistical tests were conducted at a 5% significance level. In the heatmaps: yellow color signifies acceptance of the null hypothesis, blue color indicates rejection of the null hypothesis, and black color represents cases where the statistical test is not applicable due to the comparison of identical currencies. Specifically: (

**a**) Null hypothesis: the variance of Fisher information before the pandemic for each currency on the Y-axis is greater than the variance of Fisher information before the pandemic for each currency on the X-axis. (

**b**) Null hypothesis: the variance of Fisher information during the pandemic for each currency on the Y-axis is greater than the variance of Fisher information during the pandemic for each currency on the X-axis. (

**c**) Null hypothesis: the variance of Fisher information before the pandemic for each currency on the Y-axis is greater than the variance of Fisher information during the pandemic for each currency on the X-axis. (

**d**) Reverse null hypothesis: the variance of Fisher information before the pandemic for each currency on the Y-axis is less than the variance of Fisher information before the pandemic for each currency on the X-axis. (

**e**) Reverse null hypothesis: the variance of Fisher information during the pandemic for each currency on the Y-axis is less than the variance of Fisher information during the pandemic for each currency on the X-axis. (

**f**) Reverse null hypothesis: the variance of Fisher information before the pandemic for each currency on the Y-axis is less than the variance of Fisher information during the pandemic for each currency on the X-axis.

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**Figure 1.**(

**a**): Evolution of ETH prices (black curves, left vertical axis) and returns (blue curves, right vertical axis) over the period 1 May 2019 to 20 January 2021. (

**b**): Evolution of BNB prices (black curves, left vertical axis) and returns (blue curves, right vertical axis) over the period 1 May 2019 to 20 January 2021. (

**c**): Evolution of LTC prices (black curves, left vertical axis) and returns (blue curves, right vertical axis) over the period 1 May 2019 to 20 January 2021. (

**d**): Evolution of XLM prices (black curves, left vertical axis) and returns (blue curves, right vertical axis) over the period 1 May 2019 to 20 January 2021. (

**e**): Evolution of EOS prices (black curves, left vertical axis) and returns (blue curves, right vertical axis) over the period 1 May 2019 to 20 January 2021. (

**f**): Evolution of BTC prices (black curves, left vertical axis) and returns (blue curves, right vertical axis) over the period 1 May 2019 to 20 January 2021. The red vertical dash line corresponds to the date of the WHO announcement (i.e., 11 March 2020). The green shaded area corresponds to the time period excluded from our analyses (i.e., one month before and one month after the WHO announcement).

**Figure 2.**(

**a**): Evolution of CAD prices (black curves, left vertical axis) and returns (blue curves, right vertical axis) over the period 1 May 2019 to 20 January 2021. (

**b**): Evolution of AUD prices (black curves, left vertical axis) and returns (blue curves, right vertical axis) over the period 1 May 2019 to 20 January 2021. (

**c**): Evolution of CHF prices (black curves, left vertical axis) and returns (blue curves, right vertical axis) over the period 1 May 2019 to 20 January 2021. (

**d**): Evolution of GBP prices (black curves, left vertical axis) and returns (blue curves, right vertical axis) over the period 1 May 2019 to 20 January 2021. (

**e**): Evolution of JPY prices (black curves, left vertical axis) and returns (blue curves, right vertical axis) over the period 1 May 2019 to 20 January 2021. (

**f**): Evolution of EUR prices (black curves, left vertical axis) and returns (blue curves, right vertical axis) over the period 1 May 2019 to 20 January 2021. The red vertical dash line corresponds to the date of the WHO announcement (i.e., 11 March 2020). The green shaded area corresponds to the time period excluded from our analyses (i.e., one month before and one month after the WHO announcement).

**Figure 3.**(

**a**) Temporal evolution of BTC efficiency in overall, upward, and downward market trends using asymmetric MDM. (

**b**) Temporal evolution of EUR efficiency in overall, upward, and downward market trends using asymmetric MDM. (

**c**,

**d**) The violin plots illustrate the asymmetric MDM values distribution of BTC and EUR in the period before and during the COVID-19 pandemic for the overall market trends. (

**e**,

**f**) The violin plots illustrate the asymmetric MDM values distribution of BTC and EUR in the period before and during the COVID-19 pandemic for the upward market trends. (

**g**,

**h**) The violin plots illustrate the asymmetric MDM values distribution of BTC and EUR in the period before and during the COVID-19 pandemic for the downward market trends.

**Figure 4.**(

**a**) Time evolution of fuzzy and Tsallis entropies of BTC returns. (

**b**) Time evolution of fuzzy and Tsallis entropies of EUR returns. (

**c**,

**d**) The violin plots illustrate the distribution of fuzzy entropy values for BTC and EUR returns before and during the COVID-19 pandemic. (

**e**,

**f**) The violin plots illustrate the distribution of Tsallis entropy values for BTC and EUR returns before and during the COVID-19 pandemic.

**Figure 5.**(

**a**) Time evolution of Fisher information of BTC returns. (

**b**) Time evolution of Fisher information of EUR returns. (

**c**,

**d**) The violin plots illustrate the distribution of Fisher information values for BTC and EUR returns before and during the COVID-19 pandemic.

**Figure 6.**The violin plots of the MDM value distribution for the overall market trend of: (

**a**) cryptocurrency in the period before COVID-19, (

**b**) traditional currency in the period before COVID-19, (

**c**) cryptocurrency during the COVID-19 period, and (

**d**) traditional currency during the COVID-19 period.

**Figure 7.**The violin plots of the asymmetric MDM value distribution for the upward market trends of each: (

**a**) cryptocurrency in the period before COVID-19, (

**b**) traditional currency in the period before COVID-19, (

**c**) cryptocurrency during the COVID-19 period, and (

**d**) traditional currency during the COVID-19 period.

**Figure 8.**The violin plots of the asymmetric MDM value distribution for the downward market trends of each: (

**a**) cryptocurrency in the period before COVID-19, (

**b**) traditional currency in the period before COVID-19, (

**c**) cryptocurrency during the COVID-19 period, and (

**d**) traditional currency during the COVID-19 period.

**Figure 9.**The violin plots of the fuzzy entropy value distribution of each: (

**a**) cryptocurrency in the period before COVID-19, (

**b**) traditional currency in the period before COVID-19, (

**c**) cryptocurrency during the COVID-19 period, and (

**d**) traditional currency during the COVID-19 period.

**Figure 10.**The violin plots of the Tsallis entropy value distribution of each: (

**a**) cryptocurrency in the period before COVID-19, (

**b**) traditional currency in the period before COVID-19, (

**c**) cryptocurrency during the COVID-19 period, and (

**d**) traditional currency during the COVID-19 period.

**Figure 11.**The violin plots of the Fisher information value distribution of each: (

**a**) cryptocurrency in the period before COVID-19, (

**b**) traditional currency in the period before COVID-19, (

**c**) cryptocurrency during the COVID-19 period, and (

**d**) traditional currency during the COVID-19 period.

**Table 1.**Reported probability values using one-sided t-test to compare MDM mean values for BTC and EUR. All statistical tests were performed at 5% statistical significance level.

Statistical Tests | |||
---|---|---|---|

Asymmetric MDM | |||

Overall Trend | Upward Trend | Downward Trend | |

Null Hypothesis | p-Value | p-Value | p-Value |

MDM Mean (BTC) Before COVID-19 > MDM Mean (EUR) Before COVID-19 | 1.0000 | 1.0000 | 1.0000 |

MDM Mean (BTC) Before COVID-19 < MDM Mean (EUR) Before COVID-19 | 0.0000 | 0.0000 | 0.0000 |

MDM Mean (BTC) During COVID-19 > MDM Mean (EUR) During COVID-19 | 1.0000 | 1.0000 | 1.0000 |

MDM Mean (BTC) During COVID-19 < MDM Mean (EUR) During COVID-19 | 0.0000 | 0.0000 | 0.0000 |

MDM Mean (BTC) Before COVID-19 > MDM Mean (BTC) During COVID-19 | 0.0000 | 0.0000 | 1.0000 |

MDM Mean (BTC) Before COVID-19 < MDM Mean (BTC) During COVID-19 | 1.0000 | 1.0000 | 0.0000 |

MDM Mean (EUR) Before COVID-19 > MDM Mean (EUR) During COVID-19 | 0.0000 | 0.2319 | 0.0000 |

MDM Mean (EUR) Before COVID-19 < MDM Mean (EUR) During COVID-19 | 1.0000 | 0.7681 | 1.0000 |

MDM Mean (BTC) Before COVID-19 > MDM Mean (EUR) During COVID-19 | 1.0000 | 1.0000 | 1.0000 |

MDM Mean (BTC) Before COVID-19 < MDM Mean (EUR) During COVID-19 | 0.0000 | 0.0000 | 0.0000 |

MDM Mean (EUR) Before COVID-19 > MDM Mean (BTC) During COVID-19 | 0.0000 | 0.0000 | 0.0000 |

MDM Mean (EUR) Before COVID-19 < MDM Mean (BTC) During COVID-19 | 1.0000 | 1.0000 | 1.0000 |

**Table 2.**Reported probability values using one-sided F-test to compare MDM variance values for BTC and EUR. All statistical tests were performed at a 5% statistical significance level.

Statistical Tests | |||
---|---|---|---|

Asymmetric MDM | |||

Overall Trend | Upward Trend | Downward Trend | |

Null Hypothesis | p-Value | p-Value | p-Value |

MDM Variance (BTC) Before COVID-19 > MDM Variance (EUR) Before COVID-19 | 0.9977 | 0.2204 | 0.9762 |

MDM Variance (BTC) Before COVID-19 < MDM Variance (EUR) Before COVID-19 | 0.0023 | 0.7796 | 0.0238 |

MDM Variance (BTC) During COVID-19 > MDM Variance (EUR) During COVID-19 | 0.9209 | 0.9999 | 0.9715 |

MDM Variance (BTC) During COVID-19 < MDM Variance (EUR) During COVID-19 | 0.0791 | 0.0001 | 0.0285 |

MDM Variance (BTC) Before COVID-19 > MDM Variance (BTC) During COVID-19 | 0.0000 | 0.0000 | 0.0335 |

MDM Variance (BTC) Before COVID-19 < MDM Variance (BTC) During COVID-19 | 1.0000 | 1.0000 | 0.9665 |

MDM Variance (EUR) Before COVID-19 > MDM Variance (EUR) During COVID-19 | 0.0000 | 0.0000 | 0.0536 |

MDM Variance (EUR) Before COVID-19 < MDM Variance (EUR) During COVID-19 | 1.0000 | 1.0000 | 0.9464 |

MDM Variance (BTC) Before COVID-19 > MDM Variance (EUR) During COVID-19 | 0.0000 | 0.0000 | 0.5991 |

MDM Variance (BTC) Before COVID-19 < MDM Variance (EUR) During COVID-19 | 1.0000 | 1.0000 | 0.4009 |

MDM Variance (EUR) Before COVID-19 > MDM Variance (BTC) During COVID-19 | 0.0000 | 0.0000 | 0.0002 |

MDM Variance (EUR) Before COVID-19 < MDM Variance (BTC) During COVID-19 | 1.0000 | 1.0000 | 0.9998 |

**Table 3.**Reported probability values using one-sided t-test to compare complexity measures’ (fuzzy and Tsallis entropies, and Fisher information) mean values for BTC and EUR. All statistical tests were performed at a 5% statistical significance level.

Statistical Tests | |||
---|---|---|---|

Entropies and Information | |||

Fuzzy Entropy | Tsallis Entropy | Fisher Information | |

Null Hypothesis | p-Value | p-Value | p-Value |

Ent./Info. Mean (BTC) Before COVID-19 > Ent./Info. Mean (EUR) Before COVID-19 | 0.0000 | 0.0000 | 1.0000 |

Ent./Info. Mean (BTC) Before COVID-19 < Ent./Info. Mean (EUR) Before COVID-19 | 1.0000 | 1.0000 | 0.0000 |

Ent./Info. Mean (BTC) During COVID-19 > Ent./Info. Mean (EUR) During COVID-19 | 0.0000 | 0.0000 | 1.0000 |

Ent./Info. Mean (BTC) During COVID-19 < Ent./Info. Mean (EUR) During COVID-19 | 1.0000 | 1.0000 | 0.0000 |

Ent./Info. Mean (BTC) Before COVID-19 > Ent./Info. Mean (BTC) During COVID-19 | 1.0000 | 1.0000 | 0.0000 |

Ent./Info. Mean (BTC) Before COVID-19 < Ent./Info. Mean (BTC) During COVID-19 | 0.0000 | 0.0000 | 1.0000 |

Ent./Info. Mean (EUR) Before COVID-19 > Ent./Info. Mean (EUR) During COVID-19 | 1.0000 | 1.0000 | 0.0000 |

Ent./Info. Mean (EUR) Before COVID-19 < Ent./Info. Mean (EUR) During COVID-19 | 0.0000 | 0.0000 | 1.0000 |

Ent./Info. Mean (BTC) Before COVID-19 > Ent./Info. Mean (EUR) During COVID-19 | 0.0000 | 0.0000 | 1.0000 |

Ent./Info. Mean (BTC) Before COVID-19 < Ent./Info. Mean (EUR) During COVID-19 | 1.0000 | 1.0000 | 0.0000 |

Ent./Info. Mean (EUR) Before COVID-19 > Ent./Info. Mean (BTC) During COVID-19 | 1.0000 | 1.0000 | 0.0000 |

Ent./Info. Mean (EUR) Before COVID-19 < Ent./Info. Mean (BTC) During COVID-19 | 0.0000 | 0.0000 | 1.0000 |

**Table 4.**Reported probability values using one-sided F-test to compare complexity measures’ (fuzzy and Tsallis entropies, and Fisher information) variance values for BTC and EUR. All statistical tests were performed at a 5% statistical significance level.

Statistical Tests | |||
---|---|---|---|

Entropies and Information | |||

Fuzzy Entropy | Tsallis Entropy | Fisher Information | |

Null Hypothesis | p-Value | p-Value | p-Value |

Ent./Info. Variance (BTC) Before COVID-19 > Ent./Info. Variance (EUR) Before COVID-19 | 1.0000 | 1.0000 | 1.0000 |

Ent./Info. Variance (BTC) Before COVID-19 < Ent./Info. Variance (EUR) Before COVID-19 | 0.0000 | 0.0000 | 0.0000 |

Ent./Info. Variance (BTC) During COVID-19 > Ent./Info. Variance (EUR) During COVID-19 | 0.9961 | 1.0000 | 1.0000 |

Ent./Info. Variance (BTC) During COVID-19 < Ent./Info. Variance (EUR) During COVID-19 | 0.0039 | 0.0000 | 0.0000 |

Ent./Info. Variance (BTC) Before COVID-19 > Ent./Info. Variance (BTC) During COVID-19 | 1.0000 | 1.0000 | 0.0000 |

Ent./Info. Variance (BTC) Before COVID-19 < Ent./Info. Variance (BTC) During COVID-19 | 0.0000 | 0.0000 | 1.0000 |

Ent./Info. Variance (EUR) Before COVID-19 > Ent./Info. Variance (EUR) During COVID-19 | 1.0000 | 1.0000 | 0.9991 |

Ent./Info. Variance (EUR) Before COVID-19 < Ent./Info. Variance (EUR) During COVID-19 | 0.0000 | 0.0000 | 0.0009 |

Ent./Info. Variance (BTC) Before COVID-19 > Ent./Info. Variance (EUR) During COVID-19 | 1.0000 | 1.0000 | 1.0000 |

Ent./Info. Variance (BTC) Before COVID-19 < Ent./Info. Variance (EUR) During COVID-19 | 0.0000 | 0.0000 | 0.0000 |

Ent./Info. Variance (EUR) Before COVID-19 > Ent./Info. Variance (BTC) During COVID-19 | 0.9957 | 0.0000 | 0.0000 |

Ent./Info. Variance (EUR) Before COVID-19 < Ent./Info. Variance (BTC) During COVID-19 | 0.0043 | 1.0000 | 1.0000 |

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## Share and Cite

**MDPI and ACS Style**

Zitis, P.I.; Kakinaka, S.; Umeno, K.; Stavrinides, S.G.; Hanias, M.P.; Potirakis, S.M.
The Impact of COVID-19 on Weak-Form Efficiency in Cryptocurrency and Forex Markets. *Entropy* **2023**, *25*, 1622.
https://doi.org/10.3390/e25121622

**AMA Style**

Zitis PI, Kakinaka S, Umeno K, Stavrinides SG, Hanias MP, Potirakis SM.
The Impact of COVID-19 on Weak-Form Efficiency in Cryptocurrency and Forex Markets. *Entropy*. 2023; 25(12):1622.
https://doi.org/10.3390/e25121622

**Chicago/Turabian Style**

Zitis, Pavlos I., Shinji Kakinaka, Ken Umeno, Stavros G. Stavrinides, Michael P. Hanias, and Stelios M. Potirakis.
2023. "The Impact of COVID-19 on Weak-Form Efficiency in Cryptocurrency and Forex Markets" *Entropy* 25, no. 12: 1622.
https://doi.org/10.3390/e25121622