The aim of this article is to choose the appropriate GARCH model to analyse the volatility dynamics of the Tunisian sectorial stock market indices during the COVID‐19 outbreak period. We explore the optimal conditional heteroscedasticity model with regards to goodness‐of‐fit to these sectorial indices. In particular, it proposes four models (EGARCH, FIGARCH, FIEGARCH and TGARCH) to measure asymmetric and persistence volatility. Our findings point to three interesting results. First, following the COVID‐19 outbreak, volatility is more persistent in all series. Second, the results show that building constructs materials, construction and food and beverage sector return volatilities have an insignificant asymmetric effect while consumer service, financials and distribution, industrials, basic materials and banks sector return volatilities have relatively high positive and significant asymmetric effect compared with those during the pre‐COVID‐19 period. Finally, the findings show that financial services, automobile and parts, insurance and TUNINDEX20 sectors have insignificant leverage effect. Our results can thus be useful to investors when accounting for future volatility and implementing hedging strategies under COVID‐19 crisis.

Purpose: In a first place, the present paper is designed to examine the dynamic correlations persistent between five cryptocurrencies, WTI, Gold, VIX and four stock markets (SP500, FTSE, NIKKEI and MSCIEM). In a second place, it investigates the relevant optimal hedging strategy.Design/methodology/approach: Empirically, the authors examine how WTI, Gold, VIX and five cryptocurrencies can be applicable to hedge the four stock markets. Three variants of multivariate GARCH models (DCC, ADCC and GO-GARCH) are implemented to estimate dynamic optimal hedge ratios.Findings: The reached findings prove that both of the Bitcoin and Gold turn out to display remarkable hedging commodity features, while the other assets appear to demonstrate a rather noticeable disposition to act as diversifiers. Moreover, the results show that the VIX turns out to stand as the most effectively appropriate instrument, fit for hedging the stock market indices various related refits. Furthermore, the results prove that the hedging strategy instrument was indifferent for FTSE and NIKKEI stock while for the American and emerging markets, the hedging strategy was reversed from the pre-cryptocurrency crash to the during cryptocurrency crash period.Originality/value: The first paper's empirical contribution lies in analyzing emerging cross-hedge ratios with financial assets and compare hedging effectiveness within the period of crash and the period before Bitcoin crash as well as the sensitivity of results to refits choose to compare between short term hedging strategy and long-term one.

Purpose: The paper analyzes downside and upside risk spillovers between stock markets of G7 countries and China before and during the COVID-19 pandemic.Design/methodology/approach: By using VAR-ADCC models and conditional value at risk (CoVaR) techniques, downside and upside risk spillovers between stock markets of G7 countries and China are analyzed before and during the COVID-19 pandemic.Findings: The results suggested existence of a significant and asymmetrical two-way risk transmission between majority of pair markets, but the degree of asymmetry differs according to the use of the entire cumulative distributions or distribution tails. Downside and upside risk spillovers are significantly larger before the COVID-19 pandemic in all cases except between CAC 40/DAX and S&P/SSE pairs.Originality/value: The paper used CoVaR and delta-CoVaR to investigate the downside and upside spillovers between stock markets of G7 countries and China before and during the COVID-19 pandemic.

This article attempts to assess the hedging, diversification and safe haven characteristics of gold, Bitcoin and Tether for G7 investors during the political and health crises. For this end, we use the Generalized Autoregressive Conditional Heteroskedasticity-A-Dynamic Conditional Correlation model. The findings prove that gold can be considered as a strong safe haven asset for the G7 investors during the Russia–Ukraine crisis. In contrast, cryptocurrencies fail to retain their safe haven features for Japanese investors during the COVID-19 pandemic. But, they act as diversifier assets for the rest of the G7 stock markets. The computed optimal hedge and hedging effectiveness reveal that Bitcoin displays the best hedging instrument for the United States, British, Japanese and Canadian investors during the Russia–Ukraine crisis whereas gold is considered as the best instrument for German, French and Italian investors.