The European Commission has called for new rules aimed at bringing greater transparency to Europe's fixed income markets to take a "more cautious approach", as it made several recommendations to lessen the impact of the trading overhaul.

The European Commission made the call after rejecting three of the 28 technical standards underpinning the review of the Markets in Financial Instruments Directive, known as Mifid II, on March 17. The EC has sent the standards back to the regulator that wrote them - the European Securities and Markets Authority - for "fine tuning", according to a spokeswoman.