The risk of fire sales of securities was rising yesterday after rating agencies declared that a clutch of complex debt vehicles had defaulted and with signs that the "superfund" plan backed by the US Treasury has stalled.

The developments are likely to raise investor fears and increase pressure on US authorities to take measures to shore up sentiment in the credit world. Financial markets yesterday continued to be gripped with worries about further subprime related writedowns driving the dollar to new lows and gold to a 28-year high.