The Nasdaq was down 1.91% to 3,014 in midday trading Friday, while the Dow Jones Industrial Average was off 1.19% to 13,388.
The S&P 500 fell 1.31% to 1,438.
The yield on a 10-year treasury bond fell 3.01% to 1.77%.
The price of gold was off 1.3% to $1,722 per ounce.
Shares of Huntington Beach-based BJ's Restaurants Inc. fell about 4% to $38 amid a general decline among restaurant operators. BJ's, which had a recent market value of $1 billion, is expected to release third-quarter results Oct. 25.
Aliso Viejo-based Microsemi Corp. was down about 4% to $18 for a recent market value of $1.6 billion.
Shares of Irvine-based healthcare software maker Quality Systems Inc. fell about 4% to $18 for a market value of $1.07 billion. Medical software makers were generally down on Watertown, Mass.-based Athenahealth Inc.'s third-quarter results, with sales missing analyst expectations and lower-than-expected bookings.
Santa Ana-based for-profit college operator Corinthian Colleges Inc. fell about 8% to $2.52 for a market value of $216 million. The sector took a hit following disappointing results for Phoenix-based Apollo Group Inc.’s August quarter.