So far, the ECB has maintained the principle of one member, one vote, with the six Executive Board members and the twelve national central bank presidents voting equally regardless of the economic size of the country that they represent. The ECB has had to wrestle with how to adjust voting as the euro area expands over the next decade or so.
The European Council has accepted a proposal from the ECB to cap the number of voting national central bank presidents at fifteen and to begin rotational voting once the number of countries in the euro area exceeds fifteen.