The UK accounted for 38% of global foreign exchange trading in April 2012 according to the TheCityUK's Foreign Exchange 2012 report.
Its share of global turnover was up 1% compared to six months earlier, and well ahead of the next largest centres of the US (18%), Singapore (5%) and Japan (5%). London accounted for the bulk of the UK's daily turnover, which averaged $2,000bn in April, the most recent month for which central banks have published data.
The increase in UK's share over the six months is a continuation of a decade-long trend during which the UK increased its share by 6%, from 32% in 2002. The US, Japan and Singapore have all seen a decline in their share of trading during this period.
Chris Cummings, Chief Executive of TheCityUK, commented: "The latest figures show that twice as many US dollars are traded on the foreign exchange market in the UK than in the US, and more than twice as many euros are traded in the UK than in all the euro-area countries combined.
"The increase in London's share demonstrates the importance of the UK as a centre for international financial services. However, these are competitive times and we are facing competition from other financial centres. We need to do all we can to ensure that the UK's financial and professional services sector remains globally competitive and can flourish."
Daily turnover on the global foreign exchange market, including trading in foreign exchange derivatives and products traded on exchanges, averaged around $4.9 trillion a day in 2012. Although this was down 5% on the previous year, since 2009 trading in foreign exchange has been at or near record levels.
The long-term increase in the volume of trading is largely a result of the growing importance of foreign exchange as an asset class, an increase in global fund management assets and the development of electronic trading platforms which make it easier to access this market. According to TheCityUK's report, the turbulence in financial markets did not interrupt liquidity in trading, and foreign exchange was one of the few sources of steady profits for banks since the start of the economic downturn.