The European Commission has finalised landmark rules to bring greater transparency to bond trading in the region, including an unprecedented clause requiring its top markets regulator to review - and possibly amend them - on an annual basis.

The European Securities and Markets Authority will be tasked with drawing up new technical standards each year to determine whether or not a corporate bond is liquid enough to be subject to enhanced disclosures under the revised Markets in Financial Instruments Directive - the EU's securities trading rulebook, which is coming into force in 2018.