European and Asian stock markets have fallen as investors cashed in profits from record high commodity prices, causing mining and oil shares to fall.
The volatile week continued on the New York Stock Exchange on Thursday, with leading shares rebounding.
Oil prices dropped below $100 for the first time in two weeks, gold sank to a one-month low, and copper fell too.
The Dow Jones Industrial Average rose 110 points on Thursday, having fallen 293 in Wednesday's trading and risen 420 on Tuesday.
Traders fear that an economic slowdown in the US will lead to a fall in global demand for raw materials.
It was led by financial shares such as American Express, which was up 5.5% and JPMorgan Chase, which rose 3.9%.
In Europe, the UK's FTSE 100 fell 0.7%, while in Asia there were bigger losses, with Hong Kong ending down 3.5%.
European shares closed down lower. Asian shares were also lower with Hong Kong down 3.5%.
The price of gold fell 3% to $912.85 an ounce after hitting a record high of more than $1,000 an ounce earlier this month.
London's FTSE 100 closed 0.9% lower, Frankfurt's Dax lost 0.7% and the Cac 40 in Paris fell 0.5%.
"Anyone who bought gold has been rewarded with a very healthy return," Ross Norman, managing director of TheBullionDesk.com, said.
Tokyo markets were closed for a public holiday on Thursday and many global markets are closed on Friday for the long Easter weekend.
"There's a temptation to take profit, people have done so and it's quite healthy," he said.
Commodities hit
Figures released in the US on Wednesday by the Energy Information Administration showed demand for petrol fell 3.2% in the last four weeks.
The trouble is that sentiment is appalling, and while sentiment is bad, it is very difficult to do anything about it. David Buik, Cantor Index Check latest share and commodity prices
This depressed oil prices, with a barrel of US crude hitting $99.59 on Thursday before climbing slightly. London Brent crude fell $1.71 to $99.47.
"We continue to see profit-taking among commodities," said Mike Wittner, of Societe Generale.
"There are also macro-economic concerns about the economy and thedollar has been doing better."
Shares in mining companies were down sharply. Vedanta Resources, which produces aluminium and copper, was among the hardest hit, down more than 6% at 1,881 pence.
Market nerves
Uncertainty remained amongst traders and investors, with some hoping a meeting between the Bank of England and a number of banks about financial stability would improve confidence in the market ahead of the Easter break.
"The market is very nervous," said David Buik of Cantor Index.
"The stock market is cheap, but the trouble is that sentiment is appalling, and while sentiment is bad, it is very difficult to do anything about it."
