The Nasdaq briefly turned positive on Tuesday to trade near break-even, along with the S&P 500 index, as optimism about the latest corporate earning results tempered a cautious economic assessment from U.S. Federal Reserve Chairman Ben Bernanke.

The Dow was underpinned by U.S. machinery maker Caterpillar Inc , which posted a stronger-than-expected quarterly profit.

After the benchmark S&P 500 hit a fresh 2009 intraday high of 956.53 shortly after the open, some investors opted to book profits, fueling some choppiness.

The Dow Jones industrial average <.DJI> gained 50.49 points, or 0.57 percent, to 8,898.64. The Standard & Poor's 500 Index <.SPX> rose 0.38 points, or 0.04 percent, to 951.51. The Nasdaq Composite Index <.IXIC> dipped 5.75 points, or 0.30 percent, to 1,903.54.

(Reporting by Ellis Mnyandu; Editing by Padraic Cassidy)