Fitch Ratings cut Toyota's top-notch credit rating on Wednesday, blaming the world's auto market slump and surging yen -- the latest sign that even Japan's top automaker is suffering from the global slowdown.

Global securities regulators launched three task forces to study abusive short selling, unregulated financial products and unregulated financial entities such as hedge funds, the U.S.

The price of oil fell Friday, settling at a 5 1/2 year low, as volatile stock prices raised concerns about waning global energy demand.

Global stock markets rebounded on Monday after the US government moved to stave off a crisis in confidence in Citigroup by providing the beleaguered bank with $20bn in additional capital and arranging $306bn in credit guarantees.

Stocks extended gains on Wednesday as investors went bargain hunting in the technology sector and a rise in oil prices benefited energy companies, muting concerns about the worsening global economic outlook.