• Journal of Convergence for Information Technology
• /
• v.10 no.1
• /
• pp.75-81
• /
• 2020

This study analyzed the annual difference of firm's book income, taxable income and BTD that before and after the 2009 corporate tax rate cut and 2018 corporate tax rate increase. ANOVA analysis was performed for each item by year, and post hoc was performed after homogeneity test of variance. The research results are as follows. First, the book income at corporate tax rate cut was higher than taxable income, and BTD in 2008 was significantly different from other years. Second, the book income at corporate tax rate increase was less than taxable income, and BTD in 2017 was also significantly different from other years. In other words, the firm is performing appropriate profit adjustments to reduce of tax burden when the corporate tax rate changes. Because of this, the BTD in the year immediately before the corporate tax rate change is different from other years.