The functioning of UNSC (United Nations Security Council), IMF (International Monetary Fund) and the WB (World Bank) is not fully democratic.
In the UNSC, there are five permanent members (USA, China, Russia, UK and France) who have veto powers over the decisions made by a majority of other countries. Hence, the UNSC is not democratic.
The IMF and WB are dominated by the economically powerful western countries. Decision making in these organisations are not on the basis of one member one vote. Instead, authority depends upon the financial contribution that a country makes to these organisations, which in turn reflects the economic power of the country.