This question comes up reasonably often: what is / should be the relation between institutional and subject OA repositories? There are some surprisingly strong views on this question. A JISC report just completed takes a very pragmatic line, simply asking where are the areas of common interest and where can the two types of repository help each other? The SIRIS report identifies a range of ‘drivers’ and ‘enablers’ that could form a shared agenda for collaborative work between institutional and subject repositories. Being a JISC report, the focus is on the UK, but it’s unlikely the issues are very different elsewhere.