The objective of this research is to study the companies listed on the Stock Exchange of Thailand Property and Construction Group on the relationship between corporate governance; namely the percentage of shares held by executives proportion of independent directors size of the board of directors management responsibilities of the chairman and the proportion of attendance at board meetings and 1) the operating result i.e. the return on total assets return on equity return on sales and earnings per share and 2) tax planning including the ratio of tax expenses to accounting profits before income tax and tax rate per total asset. The secondary data collected from the financial statements and the registration statement (Form 56-1) from year 2014 to 2018 in total of 71 companies is analyzed using descriptive statistics including mean and standard deviation and inferential statistics such as correlation analysis and multiple regression analysis. The research results showed that corporate governance including the shareholding percentage held by management management responsibilities of the chairman and the proportion of attendance at the Board meetings has a positive relationship with tax planning (Tax rate to total assets) with statistical significance at the level of 0.01 and 0.05. There is also a positive relationship between the operating results including the return on total assets and tax planning (Tax rate to total assets) with statistical significance of 0.01.

This research is to investigate the effects of efficiency in internal audit review of listed companies in Stock Exchange of Thailand by collecting data from 518 audit committee of listed companies in Stock Exchange of Thailand by using a questionnaire as an instrument. The results of statistics used for analyzing the collected data were simple linear regression analysis and multiple linear regression analysis indicated efficiency in internal audit reviews had positive relationships with corporate performance effectiveness and efficiency in risk management. Moreover effectiveness performance revealed a positive effect on gold achievement. The results obtained from this study could be used as guidelines for developing creating and improving the efficiency in audit committee performance and internal audit practice for organization to create reliability to the public and to be able to survive sustainably in a long period of time.

This research aims to study the relationship between profitability which included gross margin operating margin net profit margin return on assets return on equity and earnings per share and price to earnings ratio and dividend yield. The data were collected from financial statements and the annual reports of the companies listed on the Stock Exchange of Thailand (SET100). The top three companies selected should yield a maximum registered capital of each business category from the 1st January to the 31st of December during 2012 and 2015. 20 companies were chosen. The statistics used in the data analysis were descriptive and analyzed by arithmetic mean maximum minimum Standard Deviation and Pearson Correlation Coefficients to describe the characteristics of the collected data. The results of the study revealed that profitability gained from the gross margin operating margin net profit margin return on assets and return on equity. The earnings per share ratio were related to the price to earnings ratio and dividend yield at the reliability level of 95% and 99%.

This research aimed to study environmental and social disclosure levels the relationship between performance and environmental and social disclosures and the comparison of the performance and environmental and social disclosures of industrial product companies and the resource industry group listed on the Stock Exchange of Thailand. The secondary data was collected from financial statements annual reports and the data entry forms (Form 56-1) from 2015 to 2019 of the total of 130 companies. Descriptive statistics were used for the analysis namely mean and standard deviation. Inferential statistics such as correlation analysis and multiple regression analysis were also used. The research results showed that there was a Statistically significant correlation between the performance and the environmental and social disclosures of the companies in the industrial product group including reusing aspects environmental monitoring aspects and environmental law aspects and the return on equity (ROE) debt ratio (DR) and stakeholder equity (SE) at the levels of 0.01 and 0.05. In the resource industry group there was a statistically significant correlation between environmental and social disclosures namely recycling aspect with return on equity (ROE) debt ratio (DR) and income at the levels of 0.01 and 0.05.

This research aimed to study earning quality sustainability factors (ESG) and the relationship between earning quality and sustainability factors of the 59 companies listed in the sustainability index (SET THSI INDEX). The data was collected from the financial statements annual reports sustainability report and the data entry forms (Form 56-1) from 2015 to 2019. Descriptive statistics and inferential statistics were used in the data analysis including correlation analysis and multiple regression analysis The results of the study showed that most of the companies listed in the SET THSI Index had higher earning quality than the index average. The sustainability factor that has the greatest influence on earning quality is good governance. When the relationship between earning quality and sustainability factors (ESG) was analyzed it was found that there was a statistically significant correlation between environmental disclosures and good governance namely the number of the Board of Directors shareholding by Thai juristic person at the levels 0.01 and 0.05. There was a statistically significant opposite correlation between the disclosure of social responsibility information including anti-corruption aspect human rights aspect and responsibility to consumer aspect; and good governance including the proportion of shares held by family companies at levels 0.01 and 0.05.