Gulf Crude Strengthens to 5-Week High on Libya Supply Concern

Mars Blend strengthened to the highest level relative to West Texas Intermediate in almost five weeks after the brief detention of Libya’s prime minister sparked concern that renewed instability may further curb that country’s exports.

Mars, a medium-density, high-sulfur crude from the Gulf of Mexico, strengthened by 25 cents to a discount of $1.25 a barrel to the domestic benchmark at 12:10 p.m., according to data compiled by Bloomberg. That’s the narrowest since Sept. 6.

Mars and other Gulf crudes compete with foreign oils priced against European benchmark Brent for space in U.S. refineries. Brent’s premium over WTI rose as high as $8.91 a barrel today, the highest intraday level since June 7.

The spread widened after Libyan Prime Minister Ali Zaidan was released hours after being seized by a militia at a Tripoli hotel. Protests have disrupted Libya’s oil production and exports. Output fell to 300,000 barrels a day in September, the least since the same month in 2011, according to data compiled by Bloomberg.

Crude from the Southern Green Canyon strengthened by 40 cents to a discount of $3 a barrel. Poseidon crude rose 40 cents to $1.90 below WTI.

Light Louisiana Sweet weakened by 60 cents to a premium of $3. Heavy Louisiana Sweet’s premium to WTI rose 10 cents a barrel to $3.50.

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