Abstract
After some hesitancy in the 1960s and 1970s, the concept of undertaking went beyond the boundaries of legal subjectivity and became independent from the concept of legal subject. Thus, a single undertaking can contain multiple legal entities and, conversely, a single entity can be part of multiple undertakings.
Infringements of primary competition law rules are identified at the level of the undertaking (thus defined) and only secondary consequences (liability) are attributed to the entities identified as having participated in the offending undertaking. With the way the dynamics of the economy evolved at the beginning of the twenty-first century, however, questions began to arise which this concept could not provide a satisfactory answer: to the question of the internal relationship among the joint and several debtors (thus identified), or the question of the imputability of private liability to persons who, although part of the undertaking, did not participate in the infringement.