Citigroup, the biggest bank in the world by market capitalisation a little over 18 months ago, has fallen outside the world's 15 biggest financial institutions after its shares dropped in New York trading over the past two days, according to data compiled by Financial News, while HSBC is now the only UK-based bank in the world's top 65.

Citigroup's share price fell to $5.00 (€3.98) in early trading yesterday in the US, reducing its market capitalisation to $28.6bn. The bank was ranked 18 in a list of the biggest banks and financial institutions by market capitalisation at 18:00 GMT.