After rising on the opening bell Wednesday, stocks turned negative midway through the first trading session since Hurricane Sandy closed financial markets for two days.
The Dow Jones industrial average was down 27 points, or 0.2%, to 13,081 about three hours after the opening bell.
The Standard & Poor's 500 index lost four points, or 0.3%, to 1,408.
The Nasdaq lost 17 points, or 0.6%, to 2,971.
Tech giant Apple shares slid in the first day of trading following a management shake-up. Apple shares lost $10.92, or 2%, to $593.08.