In the wake of the wars on drugs and terror, countries around the globe have established Financial Intelligence Units – often abbreviated simply FIUs – that analyze financial transactions for security purposes. FIUs are relatively new public organizations that provide intelligence in the context of combatting money laundering and terrorist financing. Because financial transactions flow irrespective of national borders, FIUs are bound to join forces, coordinate their operations, and exchange their expertise and intelligence. However, FIUs are diverse organizations, that operate in varied political, cultural, and economic environments, with different legal regulations concerning privacy, data handling, and human rights. This dissertation examines how this collective of diverse security organizations overcomes geographical distance and works across operational difference, in order to follow illicit finance across borders. How do FIUs coordinate their operations transnationally and exchange financial intelligence across geographical distance and organizational difference? Drawing on literatures at the intersection of Science and Technology Studies (STS) and International Relations (IR), the dissertation adopts four ‘vantage points’ to analyze the coordination of transitional processes in practice, where political negotiation and the reconfiguration of power relations take place. The vantage points are the FIU-the Netherlands, where the financial intelligence that is exchanged is produced; the EU-FIU Platform, an EU Commission expert group that discusses how cross-border tracking practices are organized; the numbering practices of FIUs, through which FIUs coordinate cross-border operations; and circuits of trust, that is, informal relationships that make the sharing of financial intelligence possible. The dissertation concludes that it is the relatively informal nature of international agreements in combination with FIU operational autonomy that enables FIUs to overcome distance and difference and share privacy-sensitive intelligence. This conclusion raises questions of accountability, oversight, and proportionality of FIU operations. These will be of interest not only to academics, but to politicians, policymakers, and practitioners as well.