The Japanese owner of 7-Eleven is buying the Speedway chain of gas stations from Marathon Petroleum (MPC) for $21 billion. The two firms announced the cash deal in a statement late Sunday. It’s one of the biggest acquisitions in the world to be announced since the coronavirus pandemic hit earlier this year. Japanese retail giant Seven & i Holdings (SVNDF) — which owns 7-Eleven and other outlets, including supermarket chain Ito-Yokado and the Sogo and Seibu department stores — says it is the largest in the company’s history. Seven & i is the largest convenience store chain operator in Japan, with 21,000 stores there. It also owns nearly 9,800 stores in the United States and Canada. The company has been looking to expand overseas as its home market grows increasingly saturated. By acquiring Speedway, the Japanese retailer would pick up 4,000 stores and give its operations in North America a boost. With this deal, 7-Eleven would have a presence in 47 of the top 50 most populated metro areas in the United States, the company noted in a press release. The deal “will allow us to continue to grow and diversify our presence in the US, particularly in the Midwest and East Coast,” 7-Eleven President and CEO Joe DePinto said in a statement. US oil refiner Marathon Petroleum, meanwhile, announced its intention to spin off Speedway last October. That decision came after activist investor Elliott Management pushed Marathon to split into three companies “to remedy the company’s chronic underperformance.” Elliott proposed a standalone Speedway as one of those companies. Most convenience stores in the United States are located at gas stations. But analysts have long argued that Seven & i could benefit by replicating the Japanese model of building stores in urban city centers. Even so, investors were unnerved by the steep price tag of the deal. Shares of Seven & I Holdings fell nearly 9% in Monday trading in Tokyo, its biggest one-day percentage drop since March 23. It was last down nearly 6%. Along with many other retailers, Seven & i’s profits have been hit hard by stay-at-home orders during the pandemic. Net profits in the March to May quarter tumbled 73% to 13.9 billion yen ($131 million), and the company said it expects net profits to drop 45% to 120 billion yen ($1.1 billion) in the fiscal year ending February 2021.