Why partners do not fit into purchasing portfolio models by

Purchasing portfolio models have received great attention during the last two decades. The simplicity of application and the focus on power-dependence balancing has been appreciated by practitioners and academics alike. In this paper we argue that the starting point in 'given' products in addition to a dyadic perspective on purchasing management may be counteractive when purchasing efficiency is concerned. First, the object of exchange is not 'given' when firms interact, but may be subject to continuous development. Second, the dyadic perspective may obscure potentials for enhancing productivity and innovativity since both parties have other relationships that impacts on the collaboration between them.