International audienceThis paper aims at investigating the way in which strategic movements (outsourcing, merger-acquisition and restructuring) affect two dimensions of social relations: their (non)centralization and their contents. Because these movements are very frequent in the pharmaceutical industry, it is based on two case study from this sector. Ultimately, it shows that strategic movements constantly divide the unity of workers and thus increase the strong disconnection between the place of negotiation and the real place of decision into groups' structure. These movements are also an opportunity to "empty" social relations of their stakes and to lower the content of collective agreements, which deteriorate the ability of worker repr...