The article deals with a recent UE Commission staff working document on the interplay between minority shareholding and European antitrust law. According to this document, the European Merger regulation should apply not only to the acquisition of the control; but also when a firm is in the position to interfere with the main strategic decision of a competitor by mean of a minority shareholding. The Author critically analyzes the arguments on which this thesis is grounded,raising the conclusion that the costs related to its implementation could exceed the benefits outlined by the Commission. In addition, the unfair use of shareholder rights by a competitor could be tackled using other sets of rules as company law or unfair competition law.