London is the world's greatest foreign exchange market, with much of the trade conducted in the City of London. London's foreign exchange market has been described by Reuters as 'the crown jewel of London’s financial sector'. Of the $3.98 trillion daily global turnover, as measured in 2009, trading in London accounted for around $1.85 trillion, or 46.7% of the total. The pound sterling, the currency of the United Kingdom, is globally the fourth most traded currency and the third most held reserve currency.