Chicago gasoline and diesel rose against futures after Citgo Petroleum Corp. was said to be shutting some units for repairs at its Lemont, Illinois, refinery.

The discount for 87-octane gasoline in Chicago narrowed 4.5 cents to 8.5 cents versus futures traded on the New York Mercantile Exchange at 4:24 p.m., according to data compiled by Bloomberg. It was the smallest discount since April 2.

Citgo is scheduled to shut most of the main production units at its 170,500-barrel-a-day refinery by May 1, said a person familiar with plant operations who isn’t authorized to speak for the refinery and so declined to be identified. The company began shutting units yesterday, the person said.

Citgo is a unit of Petroleos de Venezuela SA, Venezuela’s state-owned oil company.

Ultra-low-sulfur diesel in Chicago strengthened 6 cents to a premium of 3 cents above heating oil futures on the New York exchange. The fuel had been trading at a discount since April 9.

To contact the reporter on this story: Dan Murtaugh in Houston at dmurtaugh@bloomberg.net

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