** Shares of burger chain Shake Shack SHAK.N down as much as 30.4% to more than a two-year low of $67.21

** Stock on track for a record low, if losses hold

** Co swings to a quarterly loss of 1 cent per share, compared with a profit of 11 cents per share a year ago.

** Also misses Q1 adjusted profit and revenue estimates - data compiled by LSEG

** Appoints Michelle Hook as new CFO, effective May 11, to succeed Katherine Fogertey, who stepped down from the role in early-March

** As of last close, stock up 18.9% YTD