The evolving nature of organizations often necessitates a reevaluation of Project Management Office (PMO) models to align with their strategic goals. Pertamina, a prominent state-owned Oil & Gas Company, recently underwent a significant transformation into a holding-subholding structure. This restructuring has led to the dispersion of over 2000 investment projects, collectively allocating an annual budget of 9-10 billion USD across six distinct subholdings. The Pertamina PMO holds a pivotal role, serving as a linchpin for project management practices within this complex organizational framework.

This paper explores the parent company's establishment of a centralized PMO service to strengthen project management procedures among its subsidiaries. The primary objective of this paper is to portray a customized PMO model that is precisely fitted to Pertamina's needs, taking into account operational boundaries, stakeholder aspirations, the sheer number of projects, and the unique features of the company's parent and subsidiary structure. This paper examines the procedural and technological requirements of implementing these tailored PMO models, highlighting challenges, presenting opportunities for improvement, and offering valuable insights into the efficient management of the diverse range of projects in Pertamina's portfolio.

In essence, this study offers a nuanced understanding of the dynamic interplay between a parent company's strategic vision, the subsidiary framework, and the services provided by Pertamina PMO which defined the customized PMO model in optimizing project management practices. The findings contribute to the academic discourse on organizational restructuring and offer practical insights for companies navigating similar complex structures in the ever-evolving global business landscape.

Keyword: Project Management Office, PMO service, Project Management, Parent Company, Subsidiaries.