Seven & I Holdings Co., which controls convenience store operator 7-Eleven, is in exclusive talks to acquire Marathon Petroleum Corp.’s Speedway gas stations for about $22 billion, according to people familiar with the matter.

The 7-Eleven owner is lining up financing for the potential transaction, which could be announced as soon as next week, said the people, who asked not to be identified as the deliberations were private.

No final decision has been made and discussions could fall through, they said.

As growth potential in Japan is looking slim, Seven & I is apparently seeking opportunities in overseas markets.

“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.

Marathon Petroleum, a refiner under pressure from activist investors to split, is exploring a sale of Speedway after announcing plans last year to spin off the retailer, sources said in January.

Speedway, with about 4,000 stores in the U.S., could be worth as much as $18 billion including debt as a standalone company, Marathon Petroleum previously said.

Speedway has also drawn interest from other suitors including EG Group, the gas station chain backed by private equity firm TDR Capital, according to people familiar with the matter.

Tokyo-based Seven & I, which traces its roots to a clothing store that was established in 1830, is Japan’s largest convenience store operator.

It oversaw more than 69,000 stores in 18 countries and regions at the end of 2018, according to its 2019 annual report.