Financial modeling, risk management of energy and environmental instruments and derivatives: past, present, and future.

In this preface, we investigate the past, study the present, and look for the future of financial modeling, risk management of energy and environmental instruments, and derivatives based on articles selected in this special issue (SI). We also summarize the significant findings of those articles and identify the research trends.

Do gasoline and diesel prices co-move? Evidence from the time-frequency domain.

This study investigates the co-movements of gasoline and diesel prices in three European countries (i.e. Germany, France, and Italy) with different fuel tax systems in place. The methodology follows a time-frequency approach, allowing us to analyse the co-movements at different frequencies and moments in time. As a novelty, we study the impact of fuel tax systems and international oil price dynamics on gasoline and diesel price co-movement. Using weekly data spanning the period from January 2005 to June 2021, the wavelet coherence analysis shows co-movements between gasoline and diesel at all frequencies, as well as during specific periods, but stronger in the long run. This evidence is recorded across all three countries, regardless of their tax systems. However, in decoupling the effect of international oil prices, the partial wavelet coherence analysis shows co-movements emerging also in the short run, with them being stronger around the global financial crisis (2008-2009). Although gasoline taxes are generally higher than diesel taxes, the analysis highlights that fuel tax systems do not influence the co-movements of fuel prices. Thus, shedding new light on the co-movement between commodity prices is fundamental, particularly in light of the current international geopolitical scene.

Health Care Expenditure in the European Union Countries: New Insights about the Convergence Process.

This paper assesses the convergence process in the health care expenditure for selected European Union (EU) countries over the past 50 years. As a novel contribution, we use bound unit root tests and, for robustness purposes, a series of tests for strict stationarity to provide new insights about the convergence process. We make a comparison between public and private health expenditure per capita and as a percentage of the gross domestic product (GDP), with a focus on six EU countries with different health care systems in place. When we consider the health expenditure per capita, we report mixed findings. We show that the spread from the group average is stationary in the cases of Finland and Portugal when the overall and public expenditure is considered. In terms of private expenditure, the convergence process is noticed only for Austria. For all other countries included in our sample, we document a non-stationary process, indicating a lack of convergence. This result is robust to the different tests we use. However, when we assess the convergence in terms of the health-expenditure-to-GDP ratio, the convergence process is recorded for Austria only. The robustness check we performed using strict stationarity tests partially confirmed the mixed results we obtained. Therefore, our findings highlight the heterogeneity of the EU health care systems and the need for identification of common solutions to the EU health care systems' problems in order to enhance their convergence processes.

The asymmetric effect of environmental policy stringency on CO2 emissions in OECD countries.

This paper uses a quantile fixed-effect panel data approach to investigate how environmental policy stringency affects CO2 emissions in a set of 32 countries from 1990 to 2015, using OECD data. This approach allows us to identify the asymmetric impact of policy stringency on emissions, considering the emission level recorded in each analysed country. More precisely, we posit that the effectiveness of environmental regulations and policies is influenced by the air pollution level. Our results show that an increase in policy stringency has a negative impact on emissions and that environmental stringency has a more powerful impact in the countries with lower levels of carbon emissions. In addition, we show that policy stringency measures only became effective after the implementation of the Kyoto agreement, whereas the policy stringency effect is stronger for EU countries at high risk of missing the 20-20-20 target in terms of greenhouse gas emissions. Lastly, policy implications refer to the need to adapt policy stringency measures to emission levels to increase their effectiveness. At the same time, the setting up of emission targets determines policymakers to be more engaged in the fight against carbon emissions.

COVID-19 and the United States financial markets' volatility.

We empirically investigate the effect of the official announcements regarding the COVID-19 new cases of infection and fatality ratio, on the financial markets volatility in the United States (US). We consider both COVID-19 global and US figures and show that the sanitary crisis enhances the S&P 500 realized volatility. Our findings are robust to different model specifications and suggest that the prolongation of the coronavirus pandemic is an important source of financial volatility, challenging the risk management activity.

CO2 emissions, renewable energy, and environmental regulations in the EU countries.

This paper analyzes the factors explaining the slight decrease of CO2 emissions in the European Union (EU), recorded during the last period. With a focus on 12 EU countries, we apply a panel data analysis over the period 1990 to 2017 and we investigate the impact of renewable energy share in energy production, and the role of EU environmental regulations, in explaining the level of CO2 emissions. Our static and dynamic panel data analysis points to a negative impact of an increased renewable energy share on CO2 emissions, while there is no clear evidence about the role of environmental regulations. It appears that the 2020 climate and energy package contributed to the reduction of pollution level, while the ratification of the Kyoto protocol by the EU countries had no significant influence. At the same time, our findings validate the environmental Kuznets curve (EKC) hypothesis and the pollution halo (PH) hypothesis, showing that foreign companies export eco-friendly technologies. Our results prove to be robust regarding the use of static fixed and random effects models, of two-stage least square models and the use of difference and system generalized method of moments (GMM) frameworks.