This article presents the amendment to the Code of Commercial Companies, introducing into the Polish legal system provisions concerning a group of companies. In particular, the characteristics of a relatively new institution in Polish legislation are analysed, which is the supervision of subsidiaries by the supervisory board of the parent company. The study presents the powers of the supervisory board of the parent company, the available tools for exercising supervision, the rules for their use, as well as the obligations imposed on the supervisory board of the parent company.