The S&P 500 was down 1.39% to 1,803.13 in afternoon trading Friday.
The Dow Jones Industrial Average fell 1.27% to 15,991.46, while the Nasdaq slipped 1.63% to 4,150.23.
The yield on a 10-year Treasury bond was down 1.12% to 2.74%.
The price of gold was up 0.22% to $1,265.10 per ounce.
Aliso Viejo-based Microsemi Corp. was off about 4% to $24.02, a day after reporting results for its quarter ended Dec. 29. The chipmaker had a recent market value of $2.26 billion.
Irvine healthcare software maker Quality Systems Inc. fell about 7% to $18.50 after rising nearly 10% on Thursday when it reported its December quarter results. The company had a recent market value of $1.11 billion.