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Stock price crash risk is of particular interest in developing countries as it poses a significant threat to investors and can have detrimental effects on the stability of emerging markets. This study investigates the role of financial flexibility in preventing stock price crash risk in the Vietnamese stock market, with a specific focus on the COVID-19 pandemic. Using the fixed-effect, system GMM, and quantile regression methods on a sample of 645 Vietnamese listed firms from 2011 to 2021, this study found that financial flexibility has a significant impact on preventing stock price crash risk. This effect was augmented during the COVID-19 crisis. Furthermore, this study found that financial flexibility mitigated the impact of the COVID-19 crisis on stock price crash risk. The findings provide important implications for firm regulators, shareholders, and investors to respond to similar future crises.

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Magnetite nanoparticles (Fe3O4 NPs) are among the most effective Fenton-Like heterogeneous catalysts for degrading environmental contaminants. However, Fe3O4 NPs aggregate easily and have poor dispersion stability because of their magnetic properties, which seriously decrease their catalytic efficiency. In this study, a novel environmentally friendly method for synthesising Fe3O4@CA was proposed. Fe3O4 NPs were immobilized on the 3D cellulose aerogels (CAs) in order to augment the degradation efficiency of p-nitrophenol (PNP) treatment and make the separation of the catalyst accessible by vacuum filtration method. Besides, CAs were fabricated from a cellulose source extracted from water hyacinth by using different cross-linking agents, such as kymene (KM) and polyvinyl alcohol-glutaraldehyde system (PVA-GA), and other drying methods, including vacuum thermal drying and freeze drying, were evaluated in the synthesis process. As-synthesized samples were analysed by various methods, including Powder X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, energy dispersive X-ray analysis and Brunauer-Emmett-Teller. Then, using ultraviolet-visible spectroscopy, the difference in the degradability of PNP of the obtained material samples was also investigated to determine their potential applications. Results highlighted that the Fe3O4-3@CA-KF catalyst with an Fe3O4 loading of 0.40 g/gCA used KM as a cross-linker and the freeze-drying method demonstrated the highest PNP removal efficiency (92.5 %) in all Fe3O4@CA samples with a H2O2 content of 5 g/L. The degradation kinetics and well-fitted pseudo-first-order model were investigated. Notably, after five successive PNP degradation experiments, this catalyst retained ∼80 % of the ability to degrade PNP, indicating its outstanding reusability. In environmental remediation, this study provides valuable insights into the development of simply separated and high-efficiency catalysts for heterogeneous catalytic reactions.

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This study investigated the impact of the COVID-19 crisis on firm risk and performance in different country-level governance qualities in the MENA region. Analyzing a sample of 739 non-financial listed firms in 12 MENA countries for the period 2011-2020, we found that the COVID-19 crisis negatively impacted the performance of firms, especially low-performance firms, in most industries, and increased firm risk in general. Moreover, we found that national governance quality plays an important role in mitigating the negative impact of the COVID-19 crisis on firm operations. Specifically, national governance quality reduces the negative impact of the COVID-19 crisis on firm performance and the positive impact of the crisis on firm risk. The results are consistent with our contention that national governance quality contributes to creating a positive environment for businesses activities and reducing economic shocks.

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This study analyzes the effectiveness of bank risk management in ASEAN countries and examines the specific role of risk governance in enhancing a bank's risk management effectiveness. Our results show that the risk management effectiveness of banks in ASEAN countries is low. Furthermore, by focusing on the insolvency risk, credit risk, and operational risk management of banks in ASEAN countries, the dynamic panel models using the two-step GMM method provide evidence that risk governance structure and its effectiveness positively correlate with risk management effectiveness in banks. Based on our findings, the regulators can establish the guidelines related to risk governance to manage a bank's risk management activities and maintain bank stability.

RESUMEN

By utilizing the Fixed effect and GMM estimators for a sample of 57 Islamic banks and 102 conventional banks from 10 countries for the period 2002-2018, we examine the effect of the audit committees' and Sharia committees' effectiveness on the bank risk-taking behavior and its transmission mechanisms. The results reveal that an audit committee's independence, number of meetings, and financial expertise negatively affect conventional banks' risk-taking, suggesting that the high effectiveness of their audit committees may constrain banks' risk-taking activities. However, no such relationship is evident or observed case of Islamic banks. Instead, with a different transmission mechanism, the proportion of female members and the financial expertise in the Sharia committees negatively affect risk-taking, but the Sharia committee size positively affects risk-taking in Sharia banks. These results indicate that a Sharia committee's high effectiveness can constrain risk-taking behaviors in Islamic banks.