NEW YORK (AP) — The latest on developments in U.S. financial markets:
Steep drops in several health care companies are pulling major stock indexes mostly lower at the opening bell.
Prescription drug distributor McKesson plunged 20 percent Friday after its revenue fell far short of analysts' forecasts. The company also cut its profit outlook.
Competitor Cardinal Health also slumped 14 percent and AmerisoruceBergen dropped 13 percent.
Online retail giant Amazon lost 5 percent after its earnings missed estimates.
Chevron was a bright spot, and gained 1.7 percent after beating earnings forecasts.
The Standard & Poor's 500 index fell 4 points, or 0.2 percent, to 2,128. The Dow Jones industrial average edged up 21 points, or 0.1 percent, to 18,195. The Nasdaq composite slid 23 points, or 0.4 percent, to 5,193.