This research was conducted with the aim of knowing the consequences behind the Notification of Stock Acquisition so that it monopolizes market share in terms of Business Competition Law at PT. Prima Top Catering By PT. Nippon Indosari Corpindo, Tbk and to find out what is the Juridical Rationality behind the Obligation of Notification of the Acquisition of Shares by PT Prima Top Boga by PT Nippon Indosari Carpindo, Tbk in terms of Business Competition Law in Indonesia. This research method is a type of normative legal research or library research. Sources of legal materials obtained are primary, secondary, and tertiary legal materials. Data collection techniques are carried out systematically, logically and rationally and can be accounted for. Based on the results of the study, it can be concluded that there are juridical problems in the acquisition of shares that there is still a discrepancy in understanding regarding the effective date of the juridical take over of shares which is understood by business actors who carry out share takeovers with the applicable laws and regulations, resulting in delays in notifying the takeover of shares to KPPU.