Strategic positioning of a manufacturer concerns choosing those service, production and supply chain related activities that an organisation should carry out internally, and those that should be external and under the ownership and control of suppliers, partners and customers. This paper describes research that has investigated how manufacturers make this decision and what, if any, are the characteristics of a successful approach to forming such decisions. Six UK manufacturing companies have been studied in-depth and, in each case, the decision making processes that practitioners actually apply have been explored, recorded and analysed. This study has revealed distinctly different styles of thinking across these companies. Based on this insight the paper proposes three key principles that manufacturers should adopt when forming strategic positioning decisions.