Cooperation of enterprises can occur in various forms, for example, a consortium, strategic alliances or holding company, which have not been defined by the Polish legislator yet. There are only definitions presented by numerous authors in the legal and economic literature. Lack of unitary and statutory definitions results in the fact that concepts of co-operation between entrepreneurs are borderline concepts of law and economics. The purpose of this article is to present the basic problems related to the issues of the consortium, strategic alliances and holding company. Due to broad problematic aspects concerning these issues, the author has chosen to develop some characteristic aspects of these three institutions. The consortium, strategic alliances and holding company are not statutory terms, they are the concepts produced by the practice, doctrine and judicature, not having unitary definition. In case of a consortium, author of the article pointed out the frequently occurring relationships between the institution and joint venture or a civilian partnership in the literature. The alliances have been generally discussed based on economic literature, due to the lack of coverage by legal regulation. The study pointed out the essence of the holding company, presenting the main reasons for its creation and its characteristics on the basis of the presented definition of this form of entrepreneurs’ cooperation.