A linkage between an FSAauthorised firm and another firm or entity falling into one of a number of defined categories, viz: a parent company; a subsidiary; a subsidiary of a parent company; entities or persons owning or controlling 20 per cent of the voting rights or capital; companies in respect of which the firm owns 20 per cent or more of the voting rights or capital. The FSA is concerned to satisfy itself that, taking account of close links, it can exercise its supervisory function effectively.