This paper reports on an ongoing research effort analyzing real-life project documentation data on post-acquisition integration cases provided by four business consultancies. I examine the effect of involving members of the target firm in workstream-level integration teams on implementation delays in the first three month of an integration project. From a theoretical perspective, such an involvement can have positive (sensegiving and human resource perspective) as well as negative effects (stakeholder power perspective). In this paper, I discuss the theoretical argument for both and explore likely contingencies, focusing on jobs lost during integration and the distribution of job losses over target and acquirer. The data examined here shows that these contingencies are indeed important: If many jobs are lost and if these jobs are lost mostly at the acquired firm, the effect of target firm involvement in integration teams is negative.