This paper reports a new type of world regionalisation based upon the location strategies of leading advanced producer service firms. To generate these ‘global practice’ regions, a principal components analysis of the office networks of 175 service firms across 138 cities is used to identify 10 common location strategies. These are interpreted as fuzzy (overlapping) and porous regional formations each consisting of two parts: a home-region and a global-outreach. The results indicate five overlapping pairs of regions: (i) intensive and extensive globalisations based upon the USA plus London (USAL); (ii) Americas and Latin America regions; (iii) Pacific Asia and China regions; (iv) Europe and Scandinavia regions; and (v) Australasian and Canadian ‘Commonwealth’ regions. All regions have worldwide global-outreaches but they differ significantly in their respective sizes and importance. Discussion of these findings elaborates upon two key points: first, globalisation is not a ‘blanket’ process creating a homogeneous world, and second, the resulting fuzzy and porous regionalisation counters the traditional ‘territorialist’ regional geographies that can provide a framework for global conflict with a more complex geography of multiple global integrations.