In this paper, we attempt to analyze the dynamic interplay between Bitcoin, social media, and the Covid-19 health crisis. For this end, we apply the fractional autoregressive vector model, fractional error correction model and impulse response functions on daily data over the period 31/12/2019-30/10/2020. Our results clearly show the short- and long-term evidence of the nexus between the Bitcoin price, social media metrics (Tweets and Google Trends) and the intensity of the Covid-19 pandemic. As well, the Covid-19 pandemic does not impact on social media metrics in the short- and long-term. On the other hand, the Covid-19 pandemic positively affects social media metrics. Also, the Covid-19 pandemic encourages investing in digital currencies such as Bitcoin. So, the Covid-19 health crisis significantly influences social media networks and Bitcoin prices.

This article aims to analyse the hedging, diversifier and safe-haven properties of Bitcoin for the US Dollar Index (USDI). We explore the long-term relationship between USDI and Bitcoin by estimating a Markov-switching autoregressive (MS-AR) model with two regimes. Thus, the data used cover the period from 18 January 2010 to 30 June 2017 for both USDI and Bitcoin. The empirical findings based on the analysis of the MS-AR model report that investing in Bitcoin involves more benefits than USDI even if the economy is in a recession. However, by examining Bitcoin and USDI volatility, the research findings underline positive dependency between the two. Such results denote that Bitcoin does not act as a hedge, and not even as a safe haven, against USDI. We found that Bitcoin is merely a diversifier for USDI. Accordingly, the outcomes will help investors and portfolio risk managers to make more up-to-date investment analyses and decisions.

Our study focuses on analyzing the impact of the digital economy on sustainable development, taking current geopolitical risks (GPR) in seventeen developed and thirteen developing countries over the period 1990–2022. We found a lack of scientific work addressing our original issue. To address this scarcity, we synthesized previous research on the contribution of the digital economy to sustainable development, the influence of geopolitical factors on this development, and the repercussions of the digital economy on socio-economic development during the COVID-19 pandemic. Our analysis based on Environmental Performance Index (EPI) and the Human Development Index (HDI) as two proxies for sustainable development, using macroeconomic indicators, various measures of the digital economy, and a global geopolitical risk index (GPRI). We adopted the Static and Dynamic Panel methodology, revealing a significantly positive contribution of the digital economy to environmental and socio-economic development in developed countries, as well as a high positive impact in developing countries. However, it is important to note that GPR have had a negative influence on environmental performance and have degraded the Human Development Index of each country. In conclusion, we highlight the strong dependence of environmental performance and socio-economic development on measures of the digital economy and macroeconomic indicators, while emphasizing the importance of mitigating geopolitical risks.