Corrected - Oil prices retreat again as oversupply bites

By Henning Gloystein

SINGAPORE (Reuters) - (Corrects Brent milestones throughout, removes chart with erroneous data, updates prices)

Crude oil prices fell on Thursday, with both Brent and U.S. WTI futures dropping around one dollar because of a global oversupply, following a volatile session the previous day when prices had rebounded sharply from near-six-year lows.

By 0836 GMT, Brent was down $1.31, or 2.6 percent, at $48.55 a barrel, while U.S. crude was trading at $47.59 a barrel, down 89 cents.

"A war for output market share means oil prices are skewed to the downside. Funds are unwinding a large positive investment premium, but further selling is possible," ANZ said on Thursday.

Wednesday's 4.5 percent surge in Brent, the biggest percentage gain since June 2012, had come as traders covered themselves on expiring options.

However, market sentiment remains bearish due to a supply glut. U.S. crude has been cheaper than Brent because soaring North American shale oil production has pulled down prices while the rest of the world market remained more tightly supplied.

But with oil producer club OPEC deciding late last year to maintain its output despite slowing Asian and European economies in order to defend its market share, including against surging U.S. competition, a glut has also appeared outside the United States.

"We are lowering our Brent price forecast: to $50.25/barrel from $72.25/barrel in 2015; to $67.50/barrel from $83/barrel in 2016; and to $77.25/barrel from $90/barrel in 2017," U.S. investment bank Jefferies International said on Thursday.

Jefferies said the use of floating storage would, in the near term, absorb barrels but noted that "those same barrels will eventually be delivered and could moderate a future price recovery".

Adding to the downward pressure on prices, Russian output has reached levels not since seen the end of the Soviet Union.

ANZ bank said that it saw a 60 percent chance Brent would range between $40 and $60 a barrel in the first half of the year, a 30 percent possibility of prices falling to $35-45 during that time and only a 10 percent chance of prices going up to $60-80 a barrel.

(Editing by Alan Raybould)