Oil prices have crashed through records every day this week, jumping by about US$7 in total.
Traders said a combination of forces have pushed prices higher, including market speculators and a decision by the Opec cartel not to hike output quotas.
New York's main oil futures contract, light sweet crude for June delivery, eased to US$123.50 a barrel from Wednesday's record of US$123.93.
US investment bank Goldman Sachs forecast this week that oil could hit US$200 in the next two years. It correctly predicted three years ago that oil would break through US$100.
Energy sector analyst Michael Davies said risks remained for investors and, given the Goldman Sachs comments, 'anything is possible in the oil market'.
AGENCE FRANCE-PRESSE