Mergers and acquisitions (M&As) are not only becoming more common globally, but they are also increasing in size and value in Sweden. The pace of this trend has not even slowed down due to the eruption of the global pandemic, there is rather a tendency showing the opposite. In solitude may this have its reasonable causes but when delving deeper into the matter may the effects of a M&A be alarming, especially for the individual. Scholars are often stressing their concerns that M&As often ends in failure or being devastating in terms of their performance. While some have argued that cultural aspects play a crucial part for the realization of a deal- transaction, have the findings either been inconclusive or inconsistent.  This thesis is therefore exploring the notion of culture and the role it plays in the M&A-process, particularly the pre-deal phase in order to shed light on the matter. By doing so have a theoretical framework been developed that connects the phases of the M&A-process with social identity theory and the modes of acculturation which the seller and buyer may desire prior to entering a deal. Thus, by investigating the actions taken by both an acquirer, “Alfa”, and a targeted firm, “Bravo”, from an acquisition in 2021, have a case study been developed for a later thematic analysis. While the former is a publicly listed company in the central regions of Sweden, is the latter a privately held company in the northern parts. Both companies operate within the construction industry which may limit the transferability to other settings. However, the methodological and qualitative design choices of this study make it possible to favor interpretations and inductive reasoning of the semi-structured interviews through which the data has been collected.  It has been found that there is no one best way for companies who are entering a M&A-deal to make sure that they will be culturally congruent with one another and that various acculturation modes might be simultaneously occurring. From the case has the modes of integration and separation been found to be present which have caused acculturation stress to transpire during the post-deal phase. Having a decentralized structure in tandem with clear communication and sharing information to those individuals being affected by the M&A has been found to be vital factors for mitigating acculturation stress, making parties more congruent, and creating favorable conditions in which implementation can be successful.