Objectives:
The aim of this study is to verify the hypothesis of decreasing volatility of budget revenues obtained from the bank tax (although still high compared to traditional taxes). The background for the research of the bank tax and conclusions resulting from it are other sectoral taxes existing in Poland, the revenues from which are, however, lower than those from the bank tax.

Material and methods:
The analysis of the variability of revenues from individual sectoral taxes in Poland in years 2016 - 2021 was conducted using descriptive statistics, Hodrick-Prescott (HP) filter and ANOVA approach. Then the Pearson correlation is examined to compare empirical data with figures resulting from the HP filter.

Results:
The results indicate that just after the introduction of the bank tax the volatility of inflows from this levy was relatively higher. There were also significant divergences between the budget forecasts and actual execution.

Conclusions:
One expect that with introduction of other new taxes the development might be similar (i.e. revenues will be difficult to estimate in first two or three years and more accurate assumptions will be made in the following periods). To the authors' knowledge, this study is the first to analyse the volatility of bank tax revenues, and the conclusions drawn (especially regarding trends in volatility changes and deviations from original expectations) are relevant to the theory and practice of fiscal policy. In turn, the inference regarding the share of bank tax revenues in Poland in relation to total tax revenues brings for the banking lobby arguments in favour of liberalizing the bank tax assessment rules.