This forum discusses the utility of ‘corporate constitutionalism’ as a category of historical analysis. Corporate constitutionalism privileges the constitutional activities of international trading corporations to understand the cross-cultural dynamics at work in European expansion. William A Pettigrew sets out the possibilities of corporate constitutionalism in the first essay which defines the concept, makes the case for viewing trading corporations as constitutional entities at home and abroad, signals some possible interpretive benefits for historians of empire, corporate historians, global historians, and constitutional historians, before offering an illustrative case study about the Royal African Company. Leading thinkers in international history (David Armitage), legal history (Paul Halliday), constitutional theory (Vicki Hsueh), and corporate history (Thomas Leng and Philip J Stern) offer their reflections on the possibilities of this new approach to the international activities of trading corporations. Although the Forum focuses on seventeenth century English trading corporations, it proposes to start a discussion about the utility of corporate constitutionalism for other European corporations and for periods both before and after the seventeenth century.