Gulf Coast gasoline weakened after refinery processing in the region reached the highest level since September.

Gross input at the plants increased 377,000 barrels a day, or 5 percent, last week, the Energy Department said yesterday. It was the largest amount since Sept. 2, department data showed.

The discount for regular 87-octane gasoline in the Gulf Coast widened 1.37 cents to 15 cents a gallon versus futures traded on the New York Mercantile Exchange at 2:04 p.m., according to data compiled by Bloomberg. Prompt delivery fell 5.31 cents to $2.7316 a gallon.

The same fuel in New York Harbor strengthened 0.12 cent to a discount of 4.63 cents versus futures.

To contact the reporter on this story: Paul Burkhardt in New York at pburkhardt@bloomberg.net.

To contact the editor responsible for this story: Dan Stets at dstets@bloomberg.net.