TY - JOUR AB - Purpose– The purpose of this paper is to analyse change processes in the post‐merger integration (PMI) phase from a complexity theory perspective. Therefore, it looks at the merged organisation as a complex adaptive system (CAS).Design/methodology/approach– Post‐merger situations borrowed from literature and a one‐day expert workshop with integration managers are related to the characteristics of CASs. During the workshop, data of the change process in different PMI phases are collected and the integration activities are analysed with a coded event history analysis.Findings– Change processes in the PMI phase are very complex and the newly merged organisations experience tension and non‐linear behaviour, but positive self‐organisation, a major property of CASs, cannot always emerge as the required prerequisites are sometimes not given.Research limitations/implications– Insights of the workshop are limited to personal statements of the participants. In order to further investigate the PMI process under a complexity perspective, additional research in the form of longitudinal case studies including methods of storytelling and narratives should be considered.Practical implications– Leaders and integration managers need a great repertoire of behaviours in order to both manage the challenging change processes by planning and controlling the integration activities and allow self‐organisation to emerge.Originality/value– The paper offers a deeper understanding of the complex change processes in the PMI phase by using the metaphor of complexity theory and CASs. VL - 5 IS - 1 SN - 1746-5265 DO - 10.1108/17465261011016531 UR - https://doi.org/10.1108/17465261011016531 AU - Lauser Bärbel PY - 2010 Y1 - 2010/01/01 TI - Post‐merger integration and change processes from a complexity perspective T2 - Baltic Journal of Management PB - Emerald Group Publishing Limited SP - 6 EP - 27 Y2 - 2024/04/20 ER -