One key asset of a firm is its knowledge stock comprising different knowledge domains (e.g., market, technological knowledge, etc.). This stock results from firm internal and/or external resources such as exchange partners (e.g. customers and R&D partners). The paper focuses on external partners and explores for which knowledge domain the usage of knowledge management systems (KMS) regarding the management of acquired knowledge from them is beneficial or detrimental to the organization. Further, the importance of each type of partner for knowledge creation is demonstrated. Using data from 154 firms, the results show that (1) each type of partner contributes to most of the knowledge domains, (2) KMS facilitate the management of the knowledge stock of a firm excluding the domain of product knowledge, and (3) the usage of KMS for managing acquired knowledge has two faces depending on the type of knowledge and on the type of exchange partner.