SUMMARY
The purpose of the article is to study the background and key factors that ensured an increase in the ranking of the Ukrainian tax system favourableness from the 174th position to the 43-d position during 2005–2016 – the greatest progress in the whole history of the “Paying Taxes” ranking. Methodology. The research was made on the basis of the countries ranking method according to the tax system favourableness, conducted by the World Bank together with the consulting firm PricewaterhouseCoopers for the implementation of the annual “Paying Taxes” ranking. The ranking is based on the analysis of: taxes and mandatory deductions that a typical medium-sized enterprise must pay in the concerned year; the administrative burden connected with the payment of taxes and deductions; processes after filing and paying taxes. Another method used in the article is the regression analysis of the impact of the unified social tax rate, the corporate income tax rate, the personal income tax rate, the volume of tax revenues, consolidated budget revenues and gross domestic product (GDP) in actual prices on the ranking position of Ukraine in the “Paying Taxes”. Results. In course of the study, it was found that the increase of the ranking of Ukraine from the 174th to the 43-d position in the “Paying Taxes” during 2005–2016 became possible due to the liberalization of taxation for 2013–2017, in particular, the reduction of the corporate income tax rate by 7% and the unified social tax rate by 10%. Other factors are as such: improving the tax administration quality: reducing the time for registration, filing and tax payment from 2185 hours in 2005 to 328 hours in 2016, with the worldwide average index of 240 hours per year; reducing the number of tax payments from 98 in 2005 to 5 (the worldwide average index is 24 payments) in 2016. Practical implications. The result of the effective tax policy of the Government of Ukraine was the reduction of the total tax burden on business from 60.3% in 2005 to 37.8% in 2016 at the worldwide average index of 40.5% at the end of the investigated period. Also, during 2005–2016, the consolidated budget revenues grew from 131.3 to 782.7 billion UAH, including tax ones – from 100.7 to 650.8 billion UAH. Value/originality. Based on the results of the study, the author substantiated that the main factor of the significant progress of the tax system of Ukraine in the “Paying Taxes” ranking (from the 174th to the 43-d position during 2005–2016) was the liberalization of taxation by reducing the tax rates of corporate income tax and a unified social tax, as well as improving the quality and efficiency of tax administration.