Caterpillar said Wednesday that its earnings fell 43 per cent in the second quarter as China's economy slowed and commodity prices sank.
Apple led a rise in technology stocks after beating analysts' estimates for quarterly earnings.
Shortly before noon, the Dow Jones industrial average was down eight points, or less than 0.1 per cent, to 15,560.
The Standard & Poor's 500 index was down two points, or less than 0.1 per cent, at 1,690.
The technology-heavy Nasdaq composite index climbed 16 points, or 0.5 per cent, to 3,596.
AT&T fell 2.3 per cent to $34.98 after its costs surged in the latest quarter. The company spent heavily on subsidizing smartphone sales.