This paper presents an analytical mapping of institutional design possibilities for alternative ways for digital platforms to institutionalise property and corporate form. It builds on the institutional imagination catalysed by three vignettes of experimental sharing economy initiatives presented towards the start of the paper, each of which highlights the imbrication and interdependence between economic and social dimensions of the sharing economy. The paper then interrogates the vignettes through three analytical entry points to the institutional design of commons-based sharing economies: platform, care and place. By remapping the vignettes’ practices around these three entry points, the paper shows how they help constitute the incipient formalisation of commons-based approaches to the sharing economy. The prospects for carrying out a redesign of property and corporate forms more generally thereby become more visible, providing a sound foundation for more in-depth empirical and historical work on alternative trajectories of the sharing economy in the future.