Updated from 2:48 p.m. EST
Oil prices plunged again Thursday, driven back below the $50-a-barrel level, as a post-election bounce in the December crude contract looked short-lived.
The December futures contract closed $2.06, or about 4%, lower at $48.82, a five week low, in floor trading on the Nymex. Prices are down 11.5% since last Wednesday.
Some traders say President Bush's victory was a boost for prices because his opponent, Sen. John Kerry, had advocated tapping the nation's Strategic Petroleum Reserve.
Weekly inventory data Wednesday showed a sizable increase in U.S. stockpiles, which failed to depress prices.
Short-term supply worries have resurfaced in the market with new sabotage attacks on Iraq's oil pipeline system and the possibility of a strike in Nigeria later this month.
Almost constant supply worries and unusually strong global demand have driven prices up more than 70% this year, making record highs commonplace.Prices topped out at more than $55 a barrel two weeks ago.