This article has been made available through the Brunel Open Access Publishing Fund.This paper reports findings from a longitudinal case study (2005–2011) of a merger between an Austrian and a German energy provider. I develop a model of socio-cultural integration processes based on an analysis of critical incidents expressed in 71 problem-centred interviews and observations with acquired and acquiring employees at four different points of time: immediately before the takeover and during the first negotiation talks, and one, three and six years after the takeover. The findings suggest that the relationship between national and organizational cultural differences and M&A outcomes is mediated by socio-cultural integration processes defined in terms of the formation of interpersonal relationships, trust and shared identity. Based on these findings I formulate specific propositions and build an evidence-based model of M&A socio-cultural integration processes that guides future research and practice
