TY - JOUR AB - Purpose– This paper aims to show that the business group – i.e. the set of firms under common ownership and control – is the most appropriate unit to study the behavior and organization of firms and define their boundaries. Particular emphasis is given to notions such as unitary direction – i.e. the influence over strategic decisions – and administrative co‐ordination which allow owners to exercise supervision and authority over the controlled companies.Design/methodology/approach– Given these aims the paper adopts an interdisciplinary perspective that relies on economics, management and law. This multidisciplinary approach is necessary for analyzing the different aspects characterizing business groups in terms of ownership, control, economic synergies between firms and internal organizational mechanisms. To support the propositions, data and information from various sources are used, ranging from official statistics on the firm's population, to sample surveys, case studies and juridical evidence. The use of different sources is justified not only by the interdisciplinary nature of the problem but also by the lack of systematic statistical evidence on the phenomenon of business groups.Findings– The authors suggest that when a company is part of a group, the business group rather than the individual company is the most appropriate “unit” for analyzing the organization and behavior of firms. This does not deny that in some cases it can be worthwhile using the legal boundary as the appropriate unit; however, most of the empirical analyses about firms consider the legal boundary without considering whether companies are independent or part of a business group.Originality/value– The authors show that forms of unitary direction and administrative co‐ordination are common in business groups; these forms can be assimilated to the internal organization of firms. For this reason they propose that the group rather than the individual company is the appropriate unit to delimit the boundary of the firm. In this sense, their main conclusion is that not considering the business group underestimates the actual firm boundaries. VL - 49 IS - 9 SN - 0025-1747 DO - 10.1108/00251741111173989 UR - https://doi.org/10.1108/00251741111173989 AU - Cainelli Giulio AU - Iacobucci Donato PY - 2011 Y1 - 2011/01/01 TI - Business groups and the boundaries of the firm T2 - Management Decision PB - Emerald Group Publishing Limited SP - 1549 EP - 1573 Y2 - 2024/05/08 ER -