Seven & i Holdings Co. is in talks to acquire U.S. convenience store operator Speedway LLC for $22 billion, a source close to the matter said Thursday.

The Tokyo-based owner of the Seven-Eleven convenience store chain is discussing the purchase of U.S. petroleum refiner Marathon Petroleum Corp.'s affiliate to expand its U.S. business to offset Japan's shrinking market, the source said.

"We are exploring various possibilities for new growth strategies, including alliances and acquisitions, but nothing has been decided at this moment," Seven & i said in a statement on Thursday.

Speedway operates around 4,000 gas stations with convenience stores in the United States.

==Kyodo

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