The financial industry has undergone a dramatic development during the last decade, leading to increased specialisation and professionalisation within the business. With the rise of Investment Banks as one of, if not the most important type of organisation in the financial industry, several of these groups can be found working within the same organisation. Here traders, analysts, brokers, and advisers in corporate finance all contribute with their speciality. Given the character of the work performed within investment banks, which criss-crosses organisational boundaries, a perspective that seeks to understand it only from within is necessarily too limited. As this work is closely related to various protagonists outside the firm, it becomes important to understand how the professionals are linked to other protagonists in the market, as well as to how they are linked directly or indirectly to one another. Following the different practices around a share, using it as a "boundary object" makes it possible to analyse both the work of these professionals, and how they are interlinked in the practice of the capital market. Earlier social studies of the financial market have primarily focused on one of the various professionals in the industry. The contribution of this study is to explain the organisation of work across boundaries, illuminating the organisation of investment banks, as well as of the capital market.