Transparency is considered as a crucial component of central bank independence as a means to make up for its ‘democratic deficit’; and central bank intervention during the Global Financial Crisis has reinforced this general perception. International organisations and domestic legislation have developed transparency standards to communicate policy objectives and results, in addition to a general evolution in favour of free access to the information in the hands of public bodies. But the ‘transparency revolution’ has not swept away central banks’ confidentiality mandate, based upon professional secrecy, private rights protection of privacy and trade secrecy, and the need to assure central banks’ capacity to continue collecting statistical data. Discernment on when to be transparent or confidential requires a high level of wisdom and experience; but mostly it requires a significant dose of ethical considerations to determine when the public interest prevails over the private interest and to explain the reasons of one or another choice. The legislation and case law show that the assurance of monetary policy effectiveness (as a public interest) is one of a decisive consideration in the balance.