The Nasdaq Composite index briefly turned negative and two other major indexes sharply pared gains as jitters about fallout from the subprime mortgage market offset optimism from economic reports.
A rise in oil prices to a 12-month high also added to nervousness.
The Dow Jones industrial average was up 47.63 points, or 0.36 percent, at 13,405.94. The Standard & Poor's 500 Index was up 3.33 points, or 0.23 percent, at 1,477.24. The Nasdaq Composite Index was up 0.06 points, or 0.00 percent, at 2,583.34.