Gasoline futures declined to a nine-week low Wednesday after the Energy Department said crude-oil inventories advanced and refinery rates increased.

Futures slipped for a third day as crude stockpiles rose to a 21-year high and refinery rates jumped 1.3 percentage points to 86 percent, the highest level since December. Gasoline stockpiles, which declined for the 11th straight week, are above the 10-year seasonal average.

“Gasoline stocks are very ample in the United States and crude-oil stocks are through the roof right now,” said James Cordier, portfolio manager at OptionSellers.com in Tampa, Florida. “Refining capacity looks like we can make all the gasoline we want.”

Gasoline for June delivery fell 2.14 cents, or 0.7 percent, to settle at $3.0757 a gallon on the New York Mercantile Exchange, the lowest settlement since Feb. 29. Gasoline has declined 9.3 percent in the second quarter, paring the 2012 gain to 14 percent. Prices traded at $3.0974 before the report’s release at 10:30 a.m. in Washington.

Oil supplies increased 2.84 million barrels to 375.9 million, the report showed. Stockpiles at Cushing, Oklahoma, the delivery point for New York futures, gained 1.21 million barrels to a record 43 million. Demand for gasoline over the past four weeks was 4.7 percent below a year earlier.

“Gasoline appears to have topped off for the year already,” Cordier said. “We could be trading here in the doldrums for a while.”

He said prices could go lower if the economy sours and equity markets plunge.

Employment Gains

Employment increased by 119,000 in April after a revised 201,000 gain the prior month, according to figures from Roseland, New Jersey-based ADP Employer Services. The median forecast of economists surveyed by Bloomberg called for a 170,000 advance.

“You had the bad ADP number this morning,” said Sander Cohan, a global transportation fuels analyst and principal with Energy Security Analysis Inc. in Wakefield, Massachusetts.

Cohan said Delta Air Lines Inc.’s agreement to buy a ConocoPhillips refinery that was to be shuttered is also pushing down prices.

Delta subsidiary Monroe Energy LLC said April 30 that it agreed to buy the ConocoPhillips operation in Trainer, Pennsylvania. Conoco planned to shut the 185,000-barrel-a-day plant unless a buyer surfaced by the end of May. Delta plans to add capacity.

Heating oil and diesel inventories dropped 1.9 million barrels to 124 million, the lowest level since October 2008. Analysts forecast a 350,000-barrel decrease.

Heating oil for June delivery fell 3.46 cents, or 1.1 percent, to $3.1425 a gallon. The price was $3.167 before the report was released.

The national unleaded average gasoline price fell to $3.803 a gallon Tuesday, according to AAA.