["Strategic Management Journal, EarlyView. ", "\nAbstract\n\nResearch Summary\nWhat role do collaborations with a target's partners play in an acquisition, and how do these collaborations evolve post‐acquisition? Research suggests that these collaborations are an important reason to acquire but often diminish post‐acquisition. But if they tend to diminish, why are they a reason to acquire? Our analysis of acquirers’ motives of 143 acquisitions of firms that collaborate with partners on 298 open‐source projects resolves the outlined puzzle and reveals two types of acquisition motives: protection‐motivated acquisitions—where acquirers focus on protecting the complementarity with the technology and the partners, and extraction‐motivated acquisitions—where acquirers focus on extracting technology and employees. We find that protection‐motivated acquisitions are associated with an intensification of collaborations, meanwhile extraction‐motivated acquisitions are associated with a diminishment of the collaboration. We contribute to research on acquisitions, collaboration, and OSS.\n\n\nManagerial Summary\nAcquisitions don’t just change ownership—they reshape collaboration with the target's partners. We studied 143 acquisitions of firms that sponsor and collaborate with partners on 298 open‐source software projects. We track contributions before and after the acquisition. We find that the motives of the acquirers are associated with different outcomes. When acquirers aim to protect complementarities, contributions from the acquired target and its partners tend to rise. When they aim to extract resources—redeploying code or talent—contributions typically decline. Managerial takeaway: when you are a stakeholder in a particular OSS, examine how likely the acquisition of its sponsors is, and what the acquirers’ motives are.\n\n"]