Shake Shack shares surge 118% on stock market debut

Shake Shack first began as a hot dog cart in New York's Madison Square Park in 2001

Shares in US burger firm Shake Shack surged 118% in their US stock market debut, valuing the company at more than $1.8bn (£1.2bn).

Trading under the symbol SHAK on the New York Stock Exchange, investor demand pushed Shake Shack's share price up from $21 to $45.90.

Started as a hot dog cart by restaurateur Danny Meyer in New York City, Shake Shack now has 63 restaurants worldwide.

Mr Meyer is set to net some $140m.

Shake Shack has benefitted from the rise of so-called "fast casual" restaurants, like Chipotle and Panera, which still offer consumers food fast, but put greater emphasis on sustainable ingredients and on-site food preparation.

In addition to burgers and concretes - Mr Meyer's term for milkshakes - Shake Shack outlets also offer wine, beer and a rotating offering of seasonal specials.