Intermediaries and relevant taxpayers may be subject to the obligation to submit reports on reportable cross-border arrangements. Relevant taxpayers need to fulfil this obligation only in three cases, namely: 1) if there is no intermediary (the taxpayer has independently designed the arrangement, as in the case of the so-called in-house expert), 2) if the intermediary invokes the obligation of professional secrecy and 3) if the intermediary is outside the European Union.