US-based fast food restaurant chain Subway has reached an agreement to be acquired by private equity firm Roark Capital.

Although the companies have not disclosed the financial details of the deal, the winning bid was more than $9.5bn, according to reports by Reuters and Bloomberg.  

Approximately $9bn will be paid upfront by Roark, with the remaining amount to be paid in future "earnout" payments, sources told Bloomberg.

Roark Capital outbid TDR Capital and Sycamore Partners, who reportedly made a final offer of $8.75bn with an earn-out.

Commenting on the deal, Subway CEO John Chidsey said: “This transaction reflects Subway's long-term growth potential and the substantial value of our brand and our franchisees around the world.

“Subway has a bright future with Roark and we are committed to continuing to focus on a win-win-win approach for our franchisees, our guests and our employees.”

Subway in its press statement said the deal is a “major milestone in a multi-year transformation journey combining Subway's global presence and brand strength with Roark's deep expertise in restaurant and franchise business models.”

With $37bn in assets under management, Roark Capital focuses on investments in consumer and business service companies.

For this deal, JP Morgan is serving as a financial advisor while Sullivan & Cromwell is serving as legal counsel to Subway.

The transaction is subject to regulatory approvals and customary closing conditions.