Studies show that social capital facilitates access to internal and external knowledge and in turn increases business value. In that respect, studies show that companies sharing some similarities such as organizational values and practices may benefit more than companies differing in various aspects. In particular, group affiliations have been shown to influence performance in specific contexts but results are mixed at best. In addition, the question of how the influence of social capital on transferring useful external knowledge might be moderated by closer affiliations between companies is virtually not addressed. Employing a survey among manufacturing companies, this paper contributes to extant research by demonstrating a moderating effect of group affiliations on the relationship between social capital and useful external knowledge.