The euro zone's biggest banks will face an annual bill of up to €15m each for being supervised by the European Central Bank, the ECB said today. 

The ECB said in a statement that the costs incurred in its new role as Europe's sole banking supervisory - which it takes over in November - are expected to amount to €260m in 2015.

As part of the new Single Supervisory Mechanism (SSM), the ECB will directly supervise up to 130 institutions classified as "significant" with assets in excess of €30 billion.

Smaller, less significant banks will remain under the remit of the national supervisory authorities. 

Of the overall sum of €260m, staff costs would amount to around 60%, premises-related costs to 10% and the remaining 30% would be accounted for by other operating expenditure such as travel, consultancy and IT services, the ECB said. 

While the ECB said that the precise costs can only be confirmed in 2015, "a preliminary analysis has shown that for 2015 the annual fee for a directly supervised bank may range from €150,000 to €15m."

However, most of the directly supervised banks would pay between €700,000 and €2m, the ECB calculated.

Similarly, around 75% of the smaller, indirectly supervised banks may pay between €2,000-7,000 per year, while the bigger banks in this category could faced a bill of about €200,000.

The annual fee would be payable on July 1. 

The ECB said it would conduct a review of the cost framework and the methodology for calculating it in 2017.