Under Directive (EU) 2016/1148, Member States were responsible for identifying the entities which met the criteria to qualify as operators of essential services. In order to eliminate the wide divergences among Member States in that regard and ensure legal certainty as regards the cybersecurity risk-management measures and reporting obligations for all relevant entities, a uniform criterion should be established that determines the entities falling within the scope of this Directive. That criterion should consist of the application of a size-cap rule, whereby all entities which qualify as medium-sized enterprises under Article 2 of the Annex to Commission Recommendation 2003/361/EC (5), or exceed the ceilings for medium-sized enterprises provided for in paragraph 1 of that Article, and which operate within the sectors and provide the types of service or carry out the activities covered by this Directive fall within its scope.