Arby's owner Inspire Brands is buying the Sonic drive-in hamburger chain.
Privately owned Inspire is paying $43.50 per share cash, or $2.3 billion, for publicly traded Sonic, which has 3,600 restaurants in the U.S. Inspire expects the deal to close by the end of this year.
Sonic, whose stock soared more than 18% on the news of the offer price Tuesday, will operate as a separate business unit within Inspire and remain based in Oklahoma City. The first Sonic opened in Oklahoma in 1953.
Inspire says Sonic's management team will also remain in place. Sonic earned $63.7 million in its 2017 fiscal year, which ended Aug. 31. That was down slightly from the previous two years.
Atlanta-based Inspire Brands was formed earlier this year when Arby'sfor around $2.4 billion. The company is mostly owned by affiliates of the private equity firm Roark Capital Group.
Inspire said Tuesday that owning multiple chains -- it already has more than 3,300 Arby's restaurants and 140 Buffalo Wild Wings outlets -- will help it share resources, including customer loyalty data and suppliers.