The article discusses interregional differentiation of sales markups of guaranteed (default) electricity suppliers (GESs) for domestic and non-domestic consumers in Russia. Since 2018, GESs tariff regulation was switched to the method of analogues’ comparison, which establishes the yardstick parameters of GESs. The tariff regulation reforming is the part of state policy intended to reduce territorial disparity between sales markups of GESs. The aim of this study is to estimate ranges of interregional differentiation of guaranteed (default) electricity suppliers’ sales markups after the switch to the method of analogues’ comparison. The hypothesis of this study states that the transition to the method of analogues’ comparison has reduced territorial disparity between sales markups of GESs. The study analyses the level ofinterregional differentiation of sales markups of GESs in 2014 – 2022. The oscillation index and the variation index have been calculatedd for the whole country divided by the scales of activity and in groups of guaranteed (default) electricity suppliers.

The results of the analysis of the tariff decisions (139 GESs in 76 regions of Russia) show that the interregional disparity between sales markups in the 2-nd half of 2022 has decreased for domestic and non-domestic consumers but remains high due to the limited impact of the method of analogues’ comparison to reduce the territorial disparity between sales markups, which has been innated in its methodology. It is necessary to improve the methodology of analogues’ comparison regulation with regard to GESs and other types of regulated electric power industries.