The S&P 500 was down 0.3% in midday trading to 1934.47.
The Dow Jones Industrial Average was down 0.4% to 16,403.16.
The NASDAQ was down 0.2% to 4,606.71.
The yield on a 10-year Treasury bond was up 0.7% to 1.95%.
The price of gold was up 1% to $1,128.
Irvine-based Quality Systems Inc. was up 6.8% to $14 and an $852 million market cap on high volume. The dental and medical practice software maker’s shares traded by midday at about three times its average rate.
Irvine-based NuGene International Inc. was up 5.9% to 90 cents and a $36 million market cap. The share price has recouped most of its losses from last week, when shares fell about 15% for the week.