Oil prices hit a four-year low in the wake of the decision by the Opec producers' cartel not to cut output.
Brent crude touched a new four-year low of $71.12 a barrel early on Friday, before recovering to trade above $73.
The price of Brent had dived by more than $5 a barrel on Thursday after Opec announced no change to its production plans following a meeting in Vienna.
The 12 Opec members decided to maintain production at 30 million barrels per day, as first agreed in December 2011.
The price of US oil fell to $67.75 a barrel - the lowest level since May 2010.
Following the meeting in Vienna, Opec's secretary general Abdallah Salem el-Badri said the group would not try to bolster prices by cutting output.
"There's a price decline. That does not mean that we should really rush and do something," he said.
The price of Brent crude has now fallen by more than a third since June, with sluggish global demand and rising production from the US being blamed for the decline.
"Welcome to the new world of oil," said Michael Wittner, senior oil analyst at Societe Generale.
"Saudi Arabia and Opec will no longer be the mechanism to balance the market, they have relinquished that role."
"Instead, the market itself - prices, in other words - will be the mechanism to rebalance the market. We cannot overstate what a dramatic and fundamental change this is for the oil market."
The falling oil price continued to hit shares in energy stocks on Friday. with shares in oil giants BP, Royal Dutch Shell and Total all down by more than 3%.
Shares in airline companies, however, rose on hopes that they will face lower fuel bills.