This article uses the example of submarine telegraphy to trace the interdependence between global communications and modern capitalism. It uncovers how cable entrepreneurs created the global telegraph network based upon particular understandings of cross-border trade, while economists such as John Maynard Keynes and John Hobson saw global communications as the foundation for capitalist exchange. Global telegraphic networks were constructed to support extant capitalist systems until the 1890s, when states and corporations began to lay telegraph cables to open up new markets, particularly in Asia and Latin America, as well as for strategic and military reasons. The article examines how the interaction between telegraphy and capitalism created particular geographical spaces and social orders despite opposition from myriad Western and non-Western groups. It argues that scholars need to account for the role of infrastructure in creating asymmetrical information and access to trade that have continued to the present day.