U.S. stocks turned negative on Monday as investors pulled back after pushing indexes up about 1 percent on better-than-expected data on manufacturing and pending home sales.

Some investors could be saying lock in (profits), why take the risk? said Kurt Brunner, portfolio manager at Swarthmore Group in Philadelphia, Pennsylvania.

Particularly after Friday was a freefall, at least in the near term it's heavier in terms of sentiment being more negative than positive.

The Dow Jones industrial average <.DJI> was still up 8.69 points, or 0.09 percent, at 9,721.42. The Standard & Poor's 500 Index <.SPX> was off 2.52 points, or 0.24 percent, to 1,033.67. The Nasdaq Composite Index <.IXIC> gave up 6.79 points, or 0.33 percent, at 2,038.32.