But while many major international banks have seen large writedowns in the wake of rising defaults among the sub-prime mortgage market, the majority of China's US mortgage-backed securities were underwritten by US government agencies such as Fannie Mae.

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With most of the country's major lenders discovering billion-dollar losses linked to bad mortgage debt as the US housing market collapsed, investment banks such as Bear Stearns needed government funds ahead of being sold off cheaply, while another, Lehman Brothers, was ultimately closed down.

BBC: US Federal Reserve 'underestimated financial crisis'

These include some of the world's leading companies, such as BMW, Lloyds, Nestle, Philips and Shell, as well as US government departments and the UK's Parliament.

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