Can Green Economy stocks hedge natural gas market risk? Evidence during Russia-Ukraine conflict and other crisis periods

One of the ultimate goals of the Green Economy is to move away from dependence on fossil energy, thereby achieving a sustainable development of a resource-saving and environment-friendly society. Thus, whether Green Economy stocks can hedge the risks of fossil energy markets, especially for natural gas market during recent crisis periods, is of great importance for both policy makers and portfolio managers. This paper identifies the time-varying connectedness and hedging effects of twelve NASDAQ OMX Green Economy sector stocks on NYMEX natural gas futures during three major turmoil events, i.e., European debt crisis, COVID-19 pandemic, and recent Russia-Ukraine conflict. The empirical results show that various Green Economy sector stocks can provide gratifying hedge effectiveness on the market risk of natural gas futures, and some of them can even perform similarly to gold and USD. Moreover, NASDAQ OMX Green Economy sector stocks offer better hedge effectiveness during recent Russia-Ukraine conflict than those of them in the periods of European debt crisis and COVID-19 pandemic. Finally, the Sharpe ratio results further show the important but time-varying roles of Green Economy sector stocks in hedging risks of natural gas market.

Connectedness among El Niño-Southern Oscillation, carbon emission allowance, crude oil and renewable energy stock markets: Time- and frequency-domain evidence based on TVP-VAR model

Understanding the interactions among climate change, carbon emission allowance trading, crude oil and renewable energy stock markets, especially the role of climate change in this system is of great significance for policy makers, energy producers/consumers and relevant investors. The present paper aims to quantify the time-varying connectedness effects among the four factors by using the TVP-VAR based extensions of both time- and frequency-domain connectedness index measurements proposed by Antonakakis et al. (2020) and Ellington and Barunik (2021) [8,48]. The empirical results suggest that, firstly, the average total connectedness among climate change, carbon emission allowance trading, crude oil and renewable energy stock markets is not so strong for the heterogenous fundamentals underlying them. Nevertheless, the time-varying total connectedness fluctuates fiercely through May 2005 to September 2021, varying from about 8% to 30% and rocket to very high levels during the global subprime mortgage crisis and the COVID-19 pandemic. Furthermore, the total connectedness mainly centers on the short-term frequency, i.e., 1–3 months. Secondly, climate change is generally the leading information contributor among the four factors, although not particularly strong, and its leading role also performs mainly on the short-term frequency (1–3 months). Thirdly, renewable energy stock market and crude oil market show tight interactions between them and they are the two major bridges of information exchanges across various time frequencies (horizons) in this system. Finally, we confirm the evidence that the primary net connectedness contributor and receiver switch frequently across different time frequencies, implying that it is extremely essential for policy makers, energy producers/consumers and investors to make time-horizon-specific regulatory, production/purchasing or investment decisions when facing the uncertain effects of climate change on the interactions among carbon emission allowance, crude oil and renewable energy stock markets.

Evaluation of inactivated COVID-19 vaccine on semen parameters in reproductive-age males: a retrospective cohort study.

During the coronavirus disease (COVID-19) epidemic, there have been concerns about the impact of vaccines on people's fertility, including the fertility of those who are currently preparing for pregnancy and those who might become pregnant in future. However, there is still a lack of research on the effect of the COVID-19 vaccine on male fertility, and it is not surprising that couples and donors have concerns regarding vaccination. In this study, a retrospective cohort study was conducted to examine semen quality before and after receipt of the inactivated COVID-19 vaccine. There were no statistically significant changes in semen parameters (volume, sperm concentration, progressive motility, and total progressive motile count) after two doses of vaccine (all P > 0.05). In summary, our study updates the most recent studies on the effects of the COVID-19 vaccine on male fertility, and the information from this study could be used to guide fertility recommendations for assisted reproductive technology (ART) patients and donors.

Normal and extreme interactions among nonferrous metal futures: A new quantile-frequency connectedness approach

Nonferrous metal markets are wildly discussed for their ultimate importance in industry production. However, the interactions among major international nonferrous metal futures, especially their extreme connectedness at different time frequencies (horizons), are rarely recognized. This paper investigates the normal and extreme interactions at various time frequencies among twelve major international nonferrous metal futures traded in LME and SHFE by proposing a new quantile-frequency connectedness measurement, which combines the quantile connectedness approach of Ando et al. (2018) and frequency connectedness method of Barunik and Krehlik (2018). The main empirical results show that, firstly, these major nonferrous metal futures maintain very tight total connectedness no matter in normal or extreme conditions, and the extreme left- and right-tail connectedness measures are larger than the one at normal case. Secondly, there is no clear difference between the extreme downside (left-tail) and upside (right-tail) total connectedness in both time and frequency domains. Thirdly, the total and net connectedness effects of these nonferrous metal futures are mainly centered in short-term frequency at both normal and extreme quantiles. Fourthly, the dynamic analysis indicates that the total connectedness among these futures are very stable throughout the data sample, even during the recent COVID-19 pandemic. Finally, these nonferrous metal futures play quite different roles in net connectedness effects across various quantiles and time frequencies.

Prevention schemes for future fresh agricultural products (FAPs) supply chain: mathematical model and experience of guaranteeing the supply of FAPs during the COVID-19 pandemic.

BACKGROUND: The COVID-19 outbreak caused short-term disruptions in the supply chain of fresh agricultural products (FAPs), which exposed the vulnerability of the existing FAP supply chain. With pandemic control being widely coordinated, the supply chain of FAPs was gradually optimized and improved. However, after the outbreak of COVID-19, achieving an effective supply of FAPs in future pandemics has become a key issue. The present work therefore aimed to construct a three-level supply chain based on the Stackelberg game model, consisting of suppliers, third-party logistics (TPL), and retailers, to guarantee the supply of FAPs. COVID-19 pandemic factors such as virus infection coefficients and pandemic prevention efforts were fully integrated into the model. RESULTS: Compared with the wholesale prices of FAPs, preservation efforts and pandemic prevention efforts have huge impacts on the retail prices of FAPs. When suppliers are in the leading position, the quality assurance effort level is positively correlated with the optimal profit. Compared with this situation, when FAP retailers are in the leading position, TPL providers show higher levels of pandemic prevention effort and FAP preservation effort. With an increase in consumer preference for pandemic prevention, the profits of supply-chain members when FAP retailers are in the leading position will gradually increase. CONCLUSION: This study reveals an effective supply mechanism for FAPs in metropolitan areas during the COVID-19 pandemic and describes the authors' experience of guaranteeing the quality and safety of FAPs for future pandemic cases. © 2021 Society of Chemical Industry.

Return connectedness among commodity and financial assets during the COVID-19 pandemic: Evidence from China and the US.

In this paper, we explore the dynamics of the return connectedness among major commodity assets (crude oil, gold and corn) and financial assets (stock, bond and currency) in China and the US during recent COVID-19 pandemic by using the time-varying connectedness measurement introduced by Antonakakis et al. (2020). Firstly, we find that the total return connectedness of the US commodity and financial assets is stronger than that of the Chinese commodity and financial assets in most cases, and both of them increase rapidly after the outbreak of COVID-19. Secondly, gold is a net transmitter of return shocks in both the Chinese and the US markets before the burst of COVID-19 pandemic, while stock and currency become net transmitters of shocks in both markets after that. Thirdly, corn usually receives the shocks from other commodity and financial assets in both China and the US markets during the COVID-19 epidemic, and the shocks it receives peak during this period, making it the strongest net receiver of shocks. Fourthly, crude oil shifts from a net transmitter to a net receiver of shocks in China after the outbreak of COVID-19, but it remains to be a net transmitter of shocks in the US. Finally, bond changes from a net receiver to a net transmitter of shocks in China after the outbreak of the epidemic, but converts from a net transmitter to a net receiver of shock in the US. The interchangeable roles of the commodity and financial assets suggest flexible regulatory and portfolio allocation strategies should be applied by policy makers and investors.

Infectious disease pandemic and permanent volatility of international stock markets: A long-term perspective.

Understanding the impact of infectious disease pandemic on stock market volatility is of great concerns for investors and policy makers, especially during recent new coronavirus spreading period. Using an extended GARCH-MIDAS model and a newly developed Infectious Disease Equity Market Volatility Tracker (EMV-ID), we investigate the effects of infectious disease pandemic on volatility of US, China, UK and Japan stock markets through January 2005 to April 2020. The empirical results show that, up to 24-month lag, infectious disease pandemic has significant positive impacts on the permanent volatility of international stock markets, even after controlling the influences of past realized volatility, global economic policy uncertainty and the volatility leverage effect. At different lags of eruptions in infectious disease pandemic, EMV-ID has distinct effects on various stock markets while it has the smallest impact on permanent volatility of China's stock market.