The Bush administration on Friday attempted to quash suggestions that the US government might have to nationalise Freddie Macand Fannie Mae, the giant mortgage companies that have unsettled the financial markets.

Hank Paulson, Treasury secretary, said: “Today our primary focus is supporting Fannie Mae and Freddie Mac in their current form as they carry out their important mission,” signalling that the Bush administration was not contemplating a rescue takeover of the two groups and wanted public shareholders to continue owning them.