The diversified firm: non formal theories versus formal models

The paper analyses critically the theoretical approaches which try to explain the emergence and growth of diversified firms. While the outstanding theory is still heavily based on non formal analysis, some recent contributions have introduced formalised models. It is argued that a further development of formal theories could be very important for a deeper understanding of the complex phenomenon of multimarket production. Moreover, formal models could be extremely useful in order to build some precise hypotheses to be tested in sound empirical works.