The appropriate choice of legal standards (LSs) in antitrust enforcement, that is, decision procedures or decision rules that provide the basis for how potentially anticompetitive conduct must be assessed in order to decide whether there is liability or not, has been hotly debated for many years. The debate has gained in intensity in recent years as a result of the concerns expressed by a significant number of academics and policy makers in many countries about the antitrust treatment of major platforms. Relying on recent developments in the literature on the choice of LSs, this article shows that the adoption of presumption-based LSs, that is, LSs that are closer to Per Se than to Effects-Based in developing jurisdictions, and the standards that would be optimal in developed jurisdictions, is consistent with the principles of minimising the costs of decision errors, and also leads to lower enforcement costs. The standards that would be optimal in developed jurisdictions, is consistent with the principles of minimising the costs of decision errors, and also leads to lower enforcement costs.