The S&P 500 fell 0.79% to 1,547.58 in afternoon trading Friday.
The Dow Jones Industrial Average was down 0.63% to 14,513.95, while the Nasdaq was off 1.04% to 3,191.48.
The yield on a 10-year treasury bond fell 3.87% to 1.69%.
The price of gold rose 1.46% to $1,575.10 per ounce.
Shares of Irvine-based disk drive maker Western Digital Corp. were down about 2% to $49.55 for a market value of $11.93 billion. Disk drive makers, including competitor Seagate Technology Public Limited Co., were generally down in midday trading Friday.
Santa Ana-based title insurance company First American Financial Corp. was up about 2% to $26.10 for a market value of $2.79 billion.
Shares of Aliso Viejo-based networking-equipment maker QLogic Corp. fell about 2% to $10.93 for a market value of $990.82 million.
Irvine-based Endologix Inc. was down about 3% to $14.98 for a market value of $941.06 million. Medical device makers were generally down in afternoon trading.