This article engages with the debate about how we come to know IR the way that we do. It seeks to contribute to this research agenda in two, related, ways: Firstly, by highlighting the influence that a previously neglected circuit of practice has on the co-constituted knowledge relationship between Global Finance and IR: the business intellectuals of the Cultural Circuit of Capital (CCC). Secondly, it argues that the Science and Technology Studies' concept of boundary objects is invaluable in accounting for both how IR's "constitutive" theorising is influenced by other circuits of practice and the co-constituted nature of "the international" as an object of investigation. To exemplify both arguments, and how they relate to one another, the article traces the co-constituted operation of the concept of the "BRIC". Following the global financial crisis in 2007/8, the CCC popularized the concept of "BRIC", which then came to operate as a boundary object between IR and Global Finance and in the process impacted on how IR knows "rising powers" and "global governance". Thus, the functionality of BRIC as a boundary object served to provide the business intellectuals of the CCC with constitutive influence on how IR knows its object of study.