The S&P 500 was at risk of snapping its winning streak as it entered the final hour and a half of trading hovering below breakeven.

The market benchmark was down 0.1%. The index dropped about 1% at the open before slowly recovering as Wall Street mostly shrugged off the Moody’s downgrade of U.S. sovereign debt.

The Dow was up 77 points, or 0.2%, but it would also be trading lower if not for a big rebound in UnitedHealth stock that tacked on 130 points to the index on Monday. The Nasdaq was down 0.2%.