Access to and diffusion of information relating to the Terrorism Finance Tracking Programme (TFTP) has become a focal point for discussions about secrecy and democracy in the European Union. This paper analyses the dynamics of secrecy and publicity in the context of post-9/11 security programmes, in particular, the TFTP. Far from a binary between secrecy and transparency, the TFTP involves complex dynamics of knowledge, and strictly regulated information distribution. The purpose of the article is threefold. First, we contribute to debates on EU secrecy and democratic oversight, by advancing an understanding of secrecy as practice. Second, we document and discuss the longer trajectory of the contested secrecy and publicity of the TFTP, through examining three ‘secrecy controversies’. Third, we ask whether the logics of secrecy in the EU are being revised and challenged in the context of transatlantic security cooperation. The rationales of secrecy deployed in security practice hinge on particular notions of potential future harm that, we argue, are shifting in the face of current understandings of the terrorist threat.