Noble Energy slumped 2 percent in early trading Monday. The company reported revenue that was well below what analysts were forecasting.
The Dow Jones industrial average lost 13 points, or 0.1 percent, to 17,672 as of 9:35 a.m. Eastern time.
The Standard & Poor's 500 index fell a point to 2,102.
The Nasdaq composite edged up seven points, or 0.1 percent, to 5,135.