The call for Marathon Petroleum to split into separate businesses is gaining momentum among activist investors.
Billionaire Paul Singer's hedge fund Elliott Management sent a letter to the board of Marathon on Wednesday, urging the refiner to divide into separate retail, midstream and refining companies to "remedy the company's chronic underperformance." Elliott owns about 2.5% in Marathon.
Hedge fund D.E. Shaw, which owns a similar sized stake in Marathon as Elliott, is also supporting the breakup of Marathon, including spinning off Speedway gas stations, sources familiar with the matter told CNBC's David Faber.
Shares of Marathon jumped more than 8% on Thursday.
Elliott said the company can unlock more than $22 billion in value for shareholders with the split-up, which could give the stock a 61% boost.
Marathon later on Wednesday responded to Elliott's letter, saying it "engages in regular communication with its shareholders and welcomes constructive input related to enhancing shareholder value."
"We will thoroughly evaluate Elliott's proposal and look forward to continuing our constructive engagement around these issues," Marathon said.
Marathon has plunged more than 34% in the past 12 months, underperforming its peers including Phillips 66 which is down 13% during the same period.