The ECB Occasional Paper Series seeks to present policy-relevant topics to a wide audience, including other policy-makers, academics, the media and the general public. Occasional Papers are, in general, organised around a specific topic or a series of inter-related topics. They provide, in rigorous – but not always necessarily technical – form material on subjects that relates to the tasks and functions of the ECB. Occasional Papers reflect work carried out by ECB staff – or co-authored by ECB staff – and are published in the name of the authors including a disclaimer. By contrast with the ECB Working Papers, which aims at a research oriented audience, Occasional Papers are not intended to present original contributions. Instead they often make public some background material used by the ECB and the Eurosystem. The Occasional Paper Series allows the ECB to present some views on subjects relating to its functions (or originating from its internal work) with the broad audience described above and that may differ depending on the subject. The target audience of OPs overlaps somewhat with that of the Monthly Bulletin articles. The main differences between some selected Occasional Papers and Monthly Bulletin articles are their size, comprehensiveness and detail of argumentation, and the need for bibliographical references.