Both academic research and public policy debate around tax havens and offshore finance typically suffer from a lack of definitional consistency. Unsurprisingly then, there is little agreement about which jurisdictions ought to be considered as tax havens—or which policy measures would result in their not being so considered. In this article we explore and make operational an alternative concept, that of a secrecy jurisdiction and present the findings of the resulting Financial Secrecy Index (FSI). The FSI ranks countries and jurisdictions according to their contribution to opacity in global financial flows, revealing a quite different geography of financial secrecy from the image of small island tax havens that may still dominate popular perceptions and some of the literature on offshore finance. Some major (secrecy-supplying) economies now come into focus. Instead of a binary division between tax havens and others, the results show a secrecy spectrum, on which all jurisdictions can be situated, and that adjustment lfor the scale of business is necessary in order to compare impact propensity. This approach has the potential to support more precise and granular research findings and policy recommendations.