The S&P 500 fell 0.64% to 1,830.49 in afternoon trading Monday.
The Dow Jones Industrial Average was off 0.60% to 16,338.89, the Nasdaq down 0.60% to 4,149.60.
The yield on a 10-year Treasury bond slipped 1.22% to 2.83%.
The price of gold rose 0.38% to $1,251.70 per ounce.
Irvine-based healthcare software maker Quality Systems Inc. was off about 8% to $19.26, for a market value of $1.2 billion. The company said Friday after market close that it expects to record an impairment charge to its Hospital Solutions Division and also warned that results for its December quarter would be below analyst estimates based on a preliminary review.
Aliso Viejo-based drug maker Avanir Pharmaceuticals Inc. rose about 8.5% to $3.52 after the company released preliminary December quarter results that showed revenue growth for its primary drug, Nuedexta. Avanir had a recent market value of $534.7 million.
Tustin drug developer Peregrine Pharmaceuticals Inc. was up about 14% to $1.85, for a market value of $296.44 million. The company said last week it received fast-track status for its lead product candidate, bavituximab.
Irvine-based TRI Pointe Homes Inc. was off about 4% to $17.26, for a market value of $545.4 million. FBR Capital lowered its rating on the company's stock last week from "outperform" to "market perform."