where, for mandatory reasons and in accordance with objective criteria, the contract can be awarded only to one particular supplier. These reasons may be of a technical, artistic or legal nature, including the exercise of exclusive rights established in accordance with applicable law, but not of an economic nature;

where, for reasons of extreme urgency brought about by events unforeseeable to the ECB, the time limits for a procurement procedure cannot be complied with;

where the ECB has classified the contract as secret or where the performance of the contract must be accompanied by special security measures, in accordance with the ECB's rules on security or where protection of the ECB's essential interests so requires. Research and development contracts in the field of banknote security require special security measures and are therefore exempt from the requirements laid down in this Decision;

in the case of supply contracts where the products involved are manufactured purely for the purpose of research, experimentation, study or development; this provision does not extend to quantity production to establish commercial viability or to recover research and development costs;

where deliverables are purchased on particularly advantageous terms from either a supplier which is definitively winding up its business activities or the receivers or liquidators appointed following a bankruptcy, an arrangement with creditors, or a similar procedure under national laws or regulations;

in the case of additional products acquired under a supply contract that replace or extend the initial products or installations, where a change of supplier would lead to disproportionate difficulties in operation and maintenance. The duration of contracts relating to such additional products shall not exceed 3 years; and

in other cases expressly provided for in this Decision.