Oil fell nearly $2 a barrel on Tuesday, tracking U.S. stock market losses ahead of what is expected to be a miserable first-quarter earnings season, while the market eyed another rise in U.S. crude inventories.
U.S. light crude for May delivery settled down $1.90 at $49.15. London Brent crude settled $1.02 lower at $51.22.
U.S. stocks fell as earnings for S&P 500 companies were expected to fall by 36.7 percent, according to ThomsonReuters data.
Crude oil prices have been closely tracking the fortunes of broader markets as investors look for clues as to when oil demand might rebound.
U.S. aluminum company Alcoa Inc
I think the road to recovery is a long one, and while we await a recovery, global oil demand will be weak, Bache Commodities broker Christopher Bellew said.
Little upside is expected from weekly U.S. inventories data due on Tuesday and Wednesday, with oil analysts predicting yet another increase in crude stocks because of high import levels and weak demand from domestic refiners.
The global recession has cut oil demand around the world, with consumption expected to be curbed for the first time since the early 1980s.
The world's top energy forecasters are likely in the coming days to reduce again their projections for world oil use this year, after big revisions in assumptions about global growth, but these cuts may be the last.
Strength in the dollar against a basket of other currencies also weighed, as commodities prices in the U.S. currency become more expensive for overseas investors.
The resumption of oil flow through the Kirkuk-Ceyhan oil pipeline also pressured prices.
Oil flow through the pipeline, which carries more than a fifth of Iraqi crude to the Turkish Mediterranean coast, had resumed on Monday, a source at the Turkish pipeline operator told Reuters.
An expanded forecast of 13 analysts called for a 1.9 million barrel rise in crude stocks, which are already running at a 16-year high, according to the U.S. Energy Information Administration (EIA).
Gasoline stocks could fall by 1 million barrels, and distillates by 0.2 million barrels, mainly due to lower refinery production. Demand may have dipped too, analysts added.
The American Petroleum Institute will release its report on Tuesday at 2030 GMT, while the EIA -- whose data is generally seen as more comprehensive -- releases its report at 1530 GMT on Wednesday.
Oil prices have gained roughly 40 percent since mid-February as equities markets rose and OPEC producers cut output, though oil's gains have been limited by continued weak global demand and rising inventory levels.
(Reporting by Edward McAllister; Editing by Marguerita Choy)
(Additional reporting by Robert Gibbons and Gene Ramos in New York, David Sheppard in London, Maryelle Demongeot in Singapore)