The research aims to examine the effect of sustainable report disclosure on investor confidence. The conceptual framework comprises 3 dimensions 30 indicators of the conceptual Global Reporting Standard (GRI). The data were collected from the annual report and sustainable report disclosure of energy groups in Thai Listed Companies from 46 companies between 2019 and 2021. The researchers used multiple regression statistics to test hypotheses. The result of the study is obviously seen that the more sustainable report disclosures are produced, the greater investor confidence has increased. With corporate governance score as a mediator variable to support investor confidence, an increase in the disclosure of sustainable report information can be attributed, in part, to factors including the size of the board of directors and the size of independent board of directors. In brief, this research contributes to corporate social responsibility through stakeholder theory, legitimacy theory and signally theory.

The research aims to examine the mediating effect of sustainability disclosure on the relationship between proactive tax planning and firm value among companies listed in the ESG100 Index. The sample comprises 114 firm-year observations from ESG100 companies during the period 2020 to 2022. This study utilizes secondary data. Moreover, a statistical regression method was applied using balanced panel data analysis, integrating both cross-sectional and time-series data to test the research hypotheses. The findings indicate that proactive tax planning has no significant effect on sustainability disclosure. However, sustainability disclosure has a positive and significant effect on firm value, whereas proactive tax planning has a negative and significant effect on firm value. This suggests that proactive tax planning may reduce firm value due to associated costs, such as tax advisory fees. Executives should therefore carefully evaluate the costs and benefits of proactive tax planning and choose strategies that optimize long-term benefits for the company. Understanding the tax costs involved in business operations should be a priority for management. The study's findings also suggest that regulatory authorities should develop tax policies that are contextually appropriate for Thailand and align with current economic conditions. In addition, the study reveals that investors place a high value on sustainability disclosure.