The far advance in computer and telecommunication technology and the evolution of Multinational corporations (MNCs) have led to an era of global economy. While MNCs strive for competitive advantage via their global information systems, diverse barriers on transborder data flow(TBDF) work on the opposite direction. Many researchers indicated that TBDF restrictions not only affected the operation of MNCs but also the management of international information systems. Some others argued that transborder data laws were either perceived as vague to follow or unable to seriously hamper some MNCs due to the harmonious relationship between MNCs and local telecommunication authorities in host countries. This obvious conflict on the magnitude of impact of TBDF regulations on MNCs' operation and management has been found in the previous research and thus triggered the need to investigate how and why the discrepancy exists. In prior research, the effects of TBDF regulations on MNCs' decision making and the impact of TBDF regulations on MNCs' global information system (GIS) management were separately investigated, little has been found to conduct the implicit relationships among TBDF regulations, MNCs' decision-making and MNCs' GIS management. And whether the relationships contribute to the context of discrepancy or not. This study aims to investigate in which way and for what reason the discrepancy exists and to provide an analytical research model to depict the implicit relationship above mentioned by interviewing seven MNCs and one local PTT (Post, Telephone and Telegraph) agency. Results indicated that vendor support, deregulation of telecommunication regulations, and the specific locations where MNCs operated (for example, MNCs suffered from TBDF regulations differently in Europe and Asia-Pacific Area) accounted for the discrepancy and also alleviated the impact of TBDF regulations on MNCs' operation. The research model, which described the implicit relationship (i.e. how TBDF regulations affect MNC decision making via its GIS), was examined and modified based on the case study results. It can serve as a tool for both academia and MNCs to have a better understanding of the current TBDF regulation environment and its possible impacts on MNCs' operation and decision-making.