Stress index of the Tax System of the Russian Federation in terms of Tax Revenues

Economic systems are increasingly exposed to external shocks of various nature, which test their resilience. The tax system, which is directly linked to the level of business activity, is one of the first to experience stress, so the ways it reacts to shock are of particular research interest. The 2020–2021 coronavirus pandemic made such studies more acute. The purpose of the paper is to develop and test new approaches in studying the resilience of the tax system in terms of tax revenues by analyzing the dynamics and structure of the tax system stress index in the Russian Federation in pre-pandemic, pandemic and recovery periods. The tax system stress index for tax revenues is calculated as the difference between the moving standard deviation and the moving average growth rate of tax revenues. We have developed a method for decomposing the stress index by source with determining the contribution of each tax to the average growth rate and to the standard deviation of the growth rate. We have also calculated the Russian Federation tax revenue stress index from December 2015 to March 2022 and identified its sources. It was found that the stress indices for almost all taxes (except for excises and state duties) are significantly positively correlated with each other. The main contribution to the growth of the stress index during the crisis and its decline within the recovery period is made by profit tax and a group of taxes on natural rent, which significantly negatively correlate with oil prices. Under the pandemic crisis in Russia, the stress index on revenue form special tax regimes also increased significantly. It was found that the personal income tax has a stabilizing effect on the tax system stress index in the crisis and post-crisis periods. During the pandemic in Russia, the damping role of excises also came to the fore, which is explained by institutional factors and changes in tax rates. The research findings can be advantageous for the authorities to make an impact on the most vulnerable components of the tax system of the Russian Federation in order to increase its resilience to crises.