Within professional service firms (PSFs), capital accumulation is dependent upon the embodied knowledge, skills, practice and trustworthiness of fee-earning staff. In legal PSFs, clients purchase idiosyncratic knowledge from individuals which are supplied through close-interaction, co-location and proximity. Legal firms expatriate staff to export English Common Law to their international offices, but simultaneously, employ the services of ‘local’ staff to practice local jurisdiction law. But, as this analysis of knowledge management and expatriation within London-headquartered firms proceeds, the findings indicate that expatriation is not homogenous for every region of the globe. In east Asia, expatriation followed a ‘Multinational’ typology, characterized by one-way knowledge diffusion from London and a demarcation of labour where expatriates manage offices, departments and teams. In contrast, expatriation in Europe and North America reflected a ‘Transnational’ typology, where knowledge was developed and diffused in a network of relationships. Here, expatriates worked with locally qualified partners and lawyers, and expatriates of other nationalities, in an environment where locals, expatriates of other nationalities and British qualified staff manage, held partnerships and lead teams. In such circumstances, expatriation was a process creating ‘transnational communities’ within the firm.