US banks hit with subpoenas over mortgage crisis

The widening of the investigation was partly responsible for a sharp drop in share prices on Wall Street overnight.

Renewed concerns about the housing market were prompted by news that the Attorney General of New York was widening an investigation into the business, which was where recent financial market storms began.

In addition, General Motors - the country's leading car-maker - announced an enormous three-month loss of $39 billion.

The high oil prices are continuing to cause concern for the stock market and the further weakness of the dollar is also a factor, the result this time of remarks by Chinese officials, suggesting the country might sell some of its dollar currency reserves. © 2007 Australian Broadcasting Corporation