Gasoline prices may rise above $4 next summer if three Philadelphia area refineries close, reducing capacity, said Edward Morse, New York-based head of commodities research at Citigroup.

Sunoco Inc. and ConocoPhillips have idled two plants in Marcus Hook and Trainer, and Sunoco plans to shut the Philadelphia refinery by July if a buyer isn't found. Together, the plants account for about half of U.S. East Coast refining.

"One of the things that's lurking in the marketplace is the consequence of this shutting in of about 700,000 barrels a day of East Coast refineries," Morse said in a Bloomberg TV interview.    - Bloomberg News