Shake Shack Shares Sizzle On Market Debut

Shake Shack, a former New York City food cart which is now a gourmet burger chain challenger to McDonald's, rocketed upon its stock market debut on Friday. Shake Shack has hit on a winning formula with millennials by serving up hormone and antibiotic-free beef, crinkle-cut fries, shakes and beer. Fifty-six-year-old founder Danny Meyer's 21% stake was worth about $390m based on the trendy company's opening day high. It served burgers free of charge on Friday to the public out of f