The evolution of the interest rates is a source of important information for the monetary policy of the Euro system. In order to harmonize the statements of the rates applied by the monetary financial institutions, the ECB decided to standardize the definitions, the methods of calculation, the periods of measurement as well as the procedure of selection of the monetary financial institutions by the national central banks. This harmonization is described in European Regulation ECB/2001/18 (20 December 2001). The national transcription of the legal texts, as well as the selection of the credit institutions is described in the methodology part of the site.

The statistical part of the site publish the weighted average of interest rates applied by the Belgian credit institutions to their loans and deposit in Euros applied to the households and the non financial companies of the euro zone. For reasons of confidentiality a certain number of statistical series are not published.