The thesis introduces thorough analysis of current approach towards margin squeeze practice, an abuse of dominant position by vertically integrated entity. For proper categorization, definition and understanding of the basic assumptions behind the strategy of margin squeeze and its application, the paper presents necessary conceptual apparatus. Further the paper deals also with regulatory framework of abuses of dominant position, national as well as international. In the practical section the paper introduces margin squeeze strategy within telecommunication industry and its regulatory framework in the Czech republic and brings recommendations for ex-ante margin squeeze testing in relation with current European regulators policy updates following the dynamic technological development of the industry.