The paper explores cost-accounting methods employed by British shipowners during the period in which large-scale enterprise initially emerged in theindustry. The findings reveal that shipowners employed what were by international standards relatively advanced techniques to control intra-unit operations. However, the unique characteristics of their systems, especially those governing inter-unit flows, were conditioned by network-based co-operative patterns of behaviour that arose within the merchant community. The article suggests that analyses of institutional development should include informal as well as formal systems, and should consider the formative influence of social and cultural forces.