competent institution
as defined in Regulation (EEC) No 1408/71 of the Council of 14 June 1971 on the application…, Article 1, point (o)
(i) the institution with which the person concerned is insured at the time of the application for benefit, or (ii) the institution from which the person concerned is entitled or would be entitled to benefits if he or a member or members of his family were resident in the territory of the Member State in which the institution is situated, or (iii) the institution designated by the competent authority of the Member State concerned, or (iv) in the case of a scheme relating to an employer's liability in respect of the benefits set out in Article 4 (1), either the employer or the insurer involved or, in default thereof, a body or authority designated by the competent authority of the Member State concerned