Even though there is abundant literature on successful cases of organizations applying knowledge management (KM) instruments, many KM initiatives have failed to achieve their knowledge and business goals. In order to foster decisions about the design of such initiatives, information is required on success factors and barriers when selecting KM instruments. Multi-agent based simulation (MABS) is suggested as an instrument to investigate potential effects of KM instruments on dependent variables such as knowledge goals, e.g., sharing of knowledge in organizations, or business goals, e.g., business performance. For such a simulation, the concept of knowledge sharing, influencing factors and their impact on business and knowledge goals have to be operationalized. This paper presents such a model which is based on an extensive multidisciplinary literature survey. The model is implemented in a MABS tool used for a series of experiments contrasting results with/without KM instruments. Finally, the paper discusses results, limitations, further enhancements and practical implications of the simulation.