Red Robin Gourmet

(RRGB) - Get Report

was the worst-performing stock on the

Nasdaq

on Friday after the company's chief executive stepped down following an investigation of his expenses account.

Shares slid $13.71, or 23%, to $46.08 on about 30 times the average daily volume. The restaurant operator also was pressured by a weak earnings outlook.

Michael Snyder, the company's CEO, chairman and president, "retired," Red Robin said in a statement. The move followed a company investigation that found entertainment and travel expenses that were "inconsistent with company policies or that lacked sufficient documentation."

Snyder will pay back the money, which the company said wasn't material to its earnings. He will be succeded by Dennis Mullen, who said in a statement that he expected a smooth transition.

"The board of directors of Red Robin responded to the issues raised by our internal investigation, and the board's response reflects our commitment to do what is in the best interests of our stockholders and our brand," Mullen, said.

As for its earnings, Red Robin posted a second-quarter profit of $7.4 million, or 45 cents a share, beating estimates by 3 cents a share. But the company put third-quarter earnings at 28 cents to 30 cents a share on revenue of $113 million to $115 million. Analysts had been expecting 49 cents a share on revenue of $119 million.