Health care stocks fell the most. Security software maker Symantec plunged after firing its CEO, and Nike fell after warning of softer sales.
The Standard & Poor's 500 lost five points, or 0.3 percent, to close at 1,866 Friday.
The Dow Jones industrial average fell almost 26 points, or 0.2 percent, to 16,305. The Nasdaq composite dropped 42 points, or 1 percent, to 4,276.
Biotech companies fell after lawmakers questioned the pricing of a Hepatitis C drug made by Gilead Sciences. Gilead lost 5 percent and Biogen Idec fell 8 percent.
Bond prices rose. The yield on the 10-year government fell to 2.74 percent.