This paper gives an insight into the application of one of the institutions of law adopted nearly twenty years ago by the government to counteract income tax evasion in Poland. The contents of the paper focusses on two main issues. First it enquires into the institution in question - in particular into its design, giving consideration both to the sources of information necessary to detect and disclose income concealment, standards of tax procedures and the legal framework behind them. In the course of this enquiry certain questions are asked and answered in relationship to the purpose, the effects, the sustainability of the regulations, that in its revised structure are in effect since 1st of January 2016, to the existing economic condition...