(7)Whereas this Directive provides for the supplementary supervision of any insurance company which is a participating undertaking in at least one insurance undertaking, reinsurance undertaking or non-member-country insurance undertaking and, under different rules, for the supplementary supervision of any insurance company whose parent undertaking is an insurance holding company, a reinsurance undertaking, a non-member-country insurance undertaking or a mixed-activity insurance holding company; whereas the supervision of individual insurance undertakings by the competent authorities remains the essential principle of insurance supervision;