Umbilical cord blood has become the focus of intense efforts to collect, screen and bank haematopoietic stem cells in hundreds of repositories around the world. UCB banking has developed through a broad spectrum of overlapping banking practices, sectors and institutional forms. Superficially at least, these sectors have been widely distinguished in bioethical and policy literature between notions of the ‘public’ and the ‘private’, the commons and the market respectively. Our purpose in this paper is to reflect more critically on these (...) distinctions and to articulate the complex practical and hybrid nature of cord blood as a ‘bio-object’ that straddles binary conceptions of the blood economies. The paper draws upon Roberto Esposito’s reflections on biopolitics and his attempt to transcend the dualistic polarisations of immunity and community, or the private and the public. We suggest that his thoughts on immunitary hospitality resonate with many of the actual features and realpolitik of a necessarily internationalised and globally distributed UCB ‘immunitary regime’. (shrink)