Much of the debate around convergence-divergence is based around comparative analysis of HR systems. However, we need now to combine these insights with work in the field of IHRM on firm-level motivations to optimise, standardise and export HR models abroad. A series of the changes are being wrought on a range of IHRM functions – recruitment, global staffing, management development and careers, and rewards - by the process of globalisation highlighting the difference between globally standardised, optimised or localised HR processes. This paper reports on a study of firm-level developments in international recruitment, selection and assessment, drawing upon an analysis of four case studies each conducted in a different context. Organisations are building IHRM functions that are shifting from the management of expatriation towards supplementary services to the business aimed at facilitating the globalisation process, and this involves capitalising upon the fragmentation of international employees. As HR realigns itself in response to this process of within-function globalisation (building new alliances with other functions such as marketing and IS) the new activity streams that are being developed and the new roles and skills of the HR function carry important implications for the study of convergence and divergence of IHRM practice. Globalisation at firm level revolves around complexity, and this is evidenced in two ways: first, the range of theory that we have to draw upon, and the competing issues that surface depending on the level of analysis that is adopted; and second, the different picture that might emerge depending upon the level of analysis that is adopted. This paper shows that although the field of IHRM has traditionally drawn upon core theories such as the resource-based view of the firm, relational and social capital, and institutional theory, once the full range of resourcing options now open to IHRM functions are considered, it is evident that we need to incorporate both more micro theory, as well as insights from contingent fields in order to explain some of the new practices that are emerging.