This is the 13th annual ranking of the FT Global 500, providing a snapshot of the world's largest companies. Exxon Mobil and PetroChina maintain their positions at numbers one and two respectively. The total market capitalisation of the Global 500 companies has fallen by 42 per cent from $26,831bn to $15,617bn. The 500th company is worth $10.1bn, compared with $19.3bn last year. Oil companies overtake banks as the most valuable sector, with 15 banks leaving the list and the number of oil companies increasing by one. The market value of the banks has more than halved from $4,116bn in 2008 to $1,937bn in 2009.

The FT annual snapshot of the world's largest companies, ranked by market capitalisation, gives a remarkable picture of how corporate fortunes have changed in the past year. View the interactive graphic

The FT500 interactive table and the full list of FT500 tables derived from the same data show how corporate fortunes have changed in the past year, highlighting relative performance of countries and sectors. The companies are ranked by market capitalisation – the greater the stock market value of a company, the higher its ranking. Market capitalisation is the share price on March 31 2009 multiplied by the number of shares issued. The figures were converted into a common currency to allow comparison, so all the figures in the main FT 500 ranking are presented in terms of the dollar at that date. We have included all companies where the free float – the proportion of shares in market circulation – is at least 15 per cent. Companies are then valued on the lines of shares that are quoted on the stock market. The full value of a listed stock is included even if part of it is tightly held. Unlisted lines of stock are excluded. Investment companies are not included.