NYSE Euronext, the world’s largest stock exchange group, is working with US regulators to improve its trading services for illiquid and unusual security types, according to its chief executive.

Duncan Niederauer, the chief executive of NYSE Euronext told Dow Jones Newswires at the World Economic Forum in Davos: “There is a severe lack of transparency in some of these instruments. There are questions from Washington: are there things we should be doing around (providing) more transparency for these instruments?”