Wall St ends flat after S&P touches new high

Investors cautious after S&P 500 index briefly hit its highest intraday level

US stocks ended the trading session flat in light volume on Wednesday as investors were cautious after the S&P 500 index briefly hit its highest intraday level since November 2007.

The Dow Jones industrial average dropped 36.56 points, or 0.26%, to 13,982.14. The Standard & Poor's 500 Index gained 0.81 point, or 0.05%, to 1,520.24. The Nasdaq Composite Index added 10.38 points, or 0.33%, to 3,196.88.