This paper contributes to current policy-makers’ debates about Global Public Investment (GPI). By emphasising its dimensions of ‘globalness’ and ‘publicness’, the paper argues that GPI could play a major role in building and implementing a Global Common Good Agenda (GCGA). It is organised into four sections — the first deals with the need for GPI and the difficulties encountered in building the agenda. The second discusses the financial requirements for its implementation. The third section presents the main dimensions of the GPI concept and its potential for GCGA financing. Finally, the fourth section presents the incentives and costs related to adopting GPI in different country groups.