A new survey in the foreign exchange (FX) market, which saw Citigroup retain its top spot in global FX dealing, revealed that the biggest investment banks are increasing their strangle hold on the currency markets.

Citigroup, UBS Warburg, Deutsche Bank, HSBC and ABN Amro dominated the rankings in a recent survey by FX Week, the specialist market publication. The survey was the biggest undertaken in the FX market, involving more than 1,000 market participants. Foreign exchange has been one of the biggest growth areas in a year when investment banking revenues have been under pressure.