An early surge on the stock market evaporated Friday as health care stocks tugged major indexes down.
Biotech companies were hit especially hard after U.S. lawmakers questioned the pricing of a hepatitis C drug made by Gilead Sciences.
The Standard & Poor's 500 index raced past an all-time high in early trading, then lost steam in the afternoon. It still finished with a solid weekly gain, up 1.4 percent.
The S&P 500 slipped 0.29 percent to close at 1,866.52 Friday.
The Dow Jones industrial average lost 28 points, falling to 16,302.77. The Nasdaq Composite dropped 0.98 percent to 4,276.79.
Health care stocks fell the most in the S&P 500 index. Gilead lost $3.46, or 4.57 percent, to $72.07. Biogen Idec fell $28.51, or 8.22 percent, to $318.53.
Nike fell after warning that a stronger U.S. dollar will dampen its results this quarter. Still, strong demand for its shoes and apparel ahead of the World Cup in June helped it beat analysts' earnings expectations in the previous quarter, the company said late Thursday. Nike, one of the 30 stocks in the Dow, lost $4.06, or 5.12 percent, to $75.21. -- AP