The bundling of a company's own resources with the complementary resources of partners often proves beneficial for companies, as it allows for the utilization of specialization advantages and the achievement of indirect network effects in the market. This is particularly true for manufacturers of complex technologies and their strategic networks. However, little has been investigated so far regarding how cooperation in strategic networks develops over the long term and whether this process also creates strategic path dependencies for the focal company. To address this research gap, this paper theoretically analyzes the long-term effects of inter-organizational complementarity based on the theory of organizational path dependence as processes of co-specialization, using a multi-level case study of SAP and its partner companies.