US stocks climbed overnight, led by retailers as the US holiday shopping season kicked off in earnest, while oil prices rose slightly.

The credit market problems remained a constant backdrop as uncertainty again characterised trade on American equity markets. The key stock indexes managed moderate gains early on, but closed significantly lower.

It has been an indecisive session on Wall Street with a late plunge in the market sending stock prices sharply lower. A rebound in crude oil prices has sent big energy issues like Exxon Mobil higher, but it has hurt large manufacturers, including Caterpillar.

US investors have waded back into the share market, cheered by developments on a number of fronts. There has been a stronger-than-expected quarterly profit result from retail leader, Wal-Mart.

Wall Street wobbled to a modestly higher finish overnight as a report showing robust US job growth failed to fully ease concerns about the problems facing the housing and finance sectors.

Merrill Lynch has ousted chairman and chief executive Stan O'Neal, just days after reporting the biggest quarterly loss in the company's history.

The head of one of the world's biggest investment banks is reportedly preparing to resign, after presiding over one of the worst losses in the history of Wall Street.

The mortgage crisis that shocked the world in recent months still keeps the international markets vulnerable, the Bank of England said Thursday.

The Australian share market fell by its largest amount in two months amid renewed concerns about credit markets. A warning by equipment company Caterpillar that the housing slump in the US was starting to spread to other parts of the economy saw US shares fall at the end of the week.

The world has marked the 20th anniversary of Black Monday, the day in 1987 when the US stock market crashed 23 per cent. The Australian market fared even worse the following day, with the All Ordinaries shedding one-quarter of its value.

The Australian share market lifted early today after a positive lead from Wall Street and hit a record high during the session.

Wall Street shares ended mostly lower overnight, with fairly lacklustre earnings news and Boeing's problems in its Dreamliner program prompting investors to lock in gains after Tuesday's record-setting session.