Shake Shack stock tumbled 30% in morning trading on Thursday after the burger chain reported an operating loss of $2.6 million. The company's earnings and revenue also fell short of Wall Street's expectations, based on a survey of analysts by LSEG. Shake Shack said its earnings per share broke even, well below Wall Street estimates of 12 cents per share. The chain also reported quarterly revenue of $367 million, missing estimates of $372 million. On the company's earnings conference call, Shake