Abstract. Although prior research on mergers and acquisitions (M&As) has suggested that cross-legacy boundary-spanners serve as organizational change agents, an emerging line of research highlights the costs of developing and maintaining boundary-spanning ties. Building on the social networks and organizational identification literatures, we develop a social network model and explore the influence of boundary-spanning on post-merger taking charge behavior. More specifically, we argue that employees without boundary-spanning ties are more likely to engage in taking charge behavior when they are closely connected to the boundary-spanners of their legacy organizations. Our analysis of the social network of a post-merger organization shows that cross-legacy boundary-spanning has a negative effect on taking charge behavior, while proximity to boundary-spanners has a positive effect. Our study also reveals that the positive effect of proximity on taking charge behavior is strongest for employees who weakly identify with the new organization.