U.S. stocks ended a volatile trading day mostly flat on Thursday as investors were reluctant to make bets a day before a critical labor market report that could magnify fears the economy is slowing.

Based on the latest available data, the Dow Jones industrial average <.DJI> slipped 41.59 points, or 0.34 percent, to end unofficially at 12,248.55. The Standard & Poor's 500 Index <.SPX> dipped 1.61 points, or 0.12 percent, to close unofficially at 1,312.94.

The Nasdaq Composite Index <.IXIC> rose 4.12 points, or 0.15 percent, to finish unofficially at 2,773.31.

(Reporting by Caroline Valetkevitch; Editing by Jan Paschal)