Corporate income tax, total tax liability, pyramidal decomposition, functional method
The taxation of corporations influences their decisions and has an impact on their profits. This fact is a reason to gain a better understanding of individual aspects of corporate income tax. The determination of the final tax liability is a process that works with a few variables, such as the tax base, tax deductions, tax rate, and tax relief. Details of corporate income tax can be described via their changes. The role and impact of individual variables can be ex-plained through the pyramidal decomposition of the total tax liability with determining relationships among indi-vidual indicators of the decomposition. With regard to the details of the total tax liability calculation, additive and multiplicative relationships can be identified among individual variables. The paper concentrates on the above-mentioned facts and uses data from selected sectors in the Czech Republic during a specific period to establish the importance of these individual variables. With real data and calculations of individual variables, the adjusted tax base is identified as the indicator with the largest impact on the total tax liability in all the studied sectors. Con-versely, research and development activities, as a kind of tax deduction, are identified as having the smallest impact.