A merger or acquisition may cause dramatic changes in a business network, which in turn affect managerial cognition as well as managerial activities. We use the concepts of ‘network pictures’ and ‘networking’ to illustrate and analyse changes in managerial sense-making and networking activities following a merger or acquisition. The paper focuses on acquiring, acquired or merging parties and those companies with which they have direct customer relationships. Based on three case studies comprising seven acquisitions and one merger, we show that following a merger or acquisition managers may need to adapt their previous network pictures in a radical way; these adaptations are, however, not always realized as shifts in network pictures and adjustments in networking activities by all the managers involved. Whereas the merging parties' network pictures and networking activities are largely driven by their perception of customers' needs and developments, it is not certain that the merger or acquisition is enacted accordingly. The paper contributes to a clearer view on the conceptual interdependence of the constructs of network pictures and networking in multi-actor situations and thus it develops a network perspective on mergers and acquisitions.