According to a previous research of tax optimization and firm value have not performed by using the Asia context as a sample data which we believe it has a different environment from the market of the previous research. Therefore, the purpose of this research is to add to the growing literature on the implications of tax optimization on the firm’s value in the context of a developing country, Thailand.
This research had examined a relationship between tax optimization and firm value in different aspects which are accounting perspective (ROA and ROE) and economic perspective (Tobin’s Q ratio) of listed firms in the Stock Exchange of Thailand for a period from 2008 to 2017. We found a significant positive relationship between tax optimization and tax optimization of the good-governed firm with the firm value from an accounting perspective, but in contrary we found an insignificant relationship between tax optimization and firm value from an economic perspective that using Tobin’s Q as a measurement of firm value. Lastly, we found a significant negative relationship between tax optimization and the firm’s additional investment.