The S&P 500 reversed course and turned negative on Monday, led by losses in energy and the materials sector.

The Dow briefly turned negative and the Nasdaq extended losses.

Shares of Alcoa fell 1.2 percent to $17.70 after being flat to higher for most of the morning session.

The Dow Jones industrial average <.DJI> was up 5.49 points, or 0.04 percent, at 12,385.54. The Standard & Poor's 500 Index <.SPX> was down 2.73 points, or 0.21 percent, at 1,325.44. The Nasdaq Composite Index <.IXIC> was down 12.31 points, or 0.44 percent, at 2,768.11.

(Reporting by Angela Moon, Editing by Leslie Adler)