In recent decades, Asian subsidiaries of Japanese manufacturing multi-national enterprises (MNEs) have faced heightened competitions from local firms to underscore the strategic importance of developing competent “host country nationals” (HCNs) to overcome their liability of foreignness. In addition, in recent literature on global MNEs, the importance of “boundary spanners” (BSs) has been pointed out in facilitating knowledge sharing across intra-organizational boundaries. Given these discussions, this study focuses on an interesting contingent relationship in the role of BSs observed in author’s interviews. i.e., In cases of “bad BSs,” “knowledge appropriation” can take place where newly promoted HCNs would monopolize their knowledge and information, and the mitigating processes of notion gap problem in grey areas management are heavily stagnated. Whereas in cases of “good BSs,” “knowledge sharing” would take place where newly promoted HCNs would be willing to share them with other members, and the mitigating processes of the notion gap problem are steadily progressed. The study proposes a framework illustrating conditions under which HCNs choose knowledge sharing over appropriation. The analysis identifies two key factors influencing this choice: dependence on personal skills and prospects for growth opportunities. The findings suggest a dynamic relationship where knowledge sharing leads to effective control and efficient knowledge transfer, fostering virtuous cycles, while knowledge appropriation results in inefficiencies, creating vicious cycles. The study calls for further research on dynamic aspects of this contingent relationship and suggests practical strategies for shifting from knowledge appropriation to sharing, thereby enhancing organizational performance in foreign subsidiaries.