Which franchise is the largest single-brand restaurant chain and the largest restaurant operator in the world (as of September 2016)?

Subway IP Inc. (stylized as SUBWAY) is an American fast food restaurant franchise that primarily sells submarine sandwiches (subs) and salads. It is owned and operated by Doctor's Associates Inc., doing business as Subway IP Inc. Subway is one of the fastest growing franchises in the world, with 44,852 restaurants in 112 countries and territories as of September 11, 2016. The United States alone has 26,646 outlets. It is the largest single-brand restaurant chain and the largest restaurant operator in the world.

In 1965, Fred DeLuca borrowed $1,000 from friend Peter Buck to start "Pete's Super Submarines" in Bridgeport, Connecticut, and in the following year they formed Doctor's Associates Inc. to oversee operations of the restaurants as the franchise expanded. The holding company derives its name from DeLuca's goal to earn enough from the business to pay tuition for medical school, as well as Buck's having a doctorate in physics. Doctor's Associates is not affiliated with, nor endorsed by, any medical organization. In 1968, the sandwich shop was renamed "Subway".