Studies concerning corporate mergers and acquisitions are mainly focused on the merging companies. Recently though, there has been an increased interest concerning connected companies, e.g. those firms having customer, supplier or other business relationships with participants in a merger or acquisition. In many countries, there is a legal prerequisite to report intended business concentration to the national competition authority for investigation. This paper investigates decisions made by a competition authority and in addition looks at studies where connected companies are mentioned by the authorities in such decisions. In very few of the investigated decisions, 2.4%, is a third party identified. Our conclusion is that customers and suppliers, if at all effected, are seen as reactive rather than active partners in a concentration. And, the concept supplier or customer relationship is not used.