Crude oil settled on the NYMEX on Wednesday at $90.48 a barrel, the highest closing price seen since Oct. 3, 2008. That follows a fourth consecutive day of gains.

Several factors are at the core of recent increases, including news from the Energy Information Administration of a third straight weekly drop in crude oil inventories, cold weather on both sides of the Atlantic, healthy retail performance and stronger performance of the Standard & Poor's 500 Index.

U.S. crude oil inventories fell 5.33 million barrels in the week to Dec. 17, a third straight weekly decline, the U.S., according to the EIA.

Futures increased 0.5 percent after a private report showed same-store sales climbed 4.2 percent last week. Holiday retail sales are a key economic indicator in the U.S., the world's largest oil-consuming country.

The S&P 500 gained 0.6 percent to 1,254.60, a level not seen since the day before Lehman Brothers Holdings Inc. filed the world's biggest bankruptcy in September 2008, Bloomberg reported.

"Holiday shopping appears to be strong, which is increasing optimism about the economy in the coming year," said Michael Lynch, president of Strategic Energy & Economic Research in Winchester, Massachusetts. "Prices are moving higher on probably premature anticipation of tightness."

China, the world's second-largest oil-consuming country, said net oil-product imports almost doubled last month to 1.44 million tons.

"There has been an insatiable appetite from hedge funds and other investors as oil demand picks up," said Christopher Bellew, senior broker at Bache Commodities Ltd. in London. "But if higher internal fuel prices and monetary tightening slow Chinese growth, and Northern Hemisphere temperatures warm up, the oil market could come off the boil."