Legitimacy defense during post-merger integration: Between coupling and compartmentalization

During post-merger integration, the realization of the benefits of potential synergies depends on managing the legitimacy of the merger. However, we still know little about how threats that change stakeholders' assessments of a merger's legitimacy are managed. This study is based on the merger case of Air New Zealand's trans-national acquisition of Ansett Australia where a delegitimizing event occurred at Ansett relatively early after the integration had started. The study builds a framework of an evolving legitimation process depicting the oscillation between legitimation responses that maintain the coupling between the two organizations and a compartmentalization response used to manage diverse stakeholders' legitimacy demands and illegitimacy spillover concerns. We explain how these legitimation responses can create an unproductive oscillation where stakeholder assessments of illegitimacy build up and ultimately become unresolvable. Our processual framework provides novel insights regarding when attempts to defend legitimacy can prove self-defeating, demonstrating how previous responses emphasizing integration or separation can affect the success of subsequent swings back to coupling or compartmentalization.