Since its founding, it has been one of the fastest-growing food chains, eventually becoming a public company filing for an initial public offering of stock in late 2014.
In 2004, it received a permit to open a permanent kiosk within the park, expanding its menu from New York–style hot dogs to one with hamburgers, hot dogs, fries and its namesake milkshakes. It started out as a hot dog cart inside Madison Square Park in 2001, and its popularity steadily grew. Shake Shack is an American fast casual restaurant chain based in New York City.