Potbelly guidance ruins investors' appetite for the stock, at lowest level since market debut

Potbelly's stock has tumbled to its lowest point since its market debut in October, reeling from a softer-than-expected second-quarter forecast and full-year guidance.

Late Wednesday the restaurant operator known for its toasted sandwiches said that it anticipates an adjusted profit of approximately 6 cents per share for its fiscal second quarter ended June 29. It predicts revenue of about $83.6 million.

Analysts surveyed by FactSet expected second quarter profit of 9 cents per share on revenue of $85 million.

Potbelly is expected to report its second-quarter results on Aug. 5.

Chairman and CEO Aylwin Lewis said in a statement that the company was revising its full-year outlook "to reflect current trends within our business."

Potbelly Corp. now anticipates full-year sales at stores open at least a year to be flat to down by a low single-digit percentage rate. Its previous guidance was for the figure to rise by a low single-digit percentage rate.

Sales at stores open at least a year is a key gauge of a company's health because it excludes results from locations recently opened or closed.

Potbelly foresees a 2014 adjusted profit of about 18 cents to 21 cents per share. Wall Street had been.is calling for 27 cents per share.

Shares of Potbelly plunged $3.49, or 23.8 percent, to $11.16 in Thursday morning trading. Earlier in session the stock slid to $10.95 — the lowest level since its debut on the Nasdaq nine months ago.