The level of pre-merger notification thresholds is a matter of extreme importance to guarantee an effective and efficient merger review regime. On the one hand, the higher the thresholds the higher the risk of having potential anticompetitive mergers that might not be assessed by the relative authority. On the other hand, imposing notification to all mergers would be costly and inefficient for both the competition authority and the merging parties. This note presents an economic approach to set the optimal pre-merger notification threshold and provides some initial thoughts to fill the literature gap on the topic.