The S&P 500 was down 0.3% in midday trading to 2,719.52.
The Dow Jones Industrial Average declined 0.3% to 24,733.98.
The Nasdaq was up 0.1% to 7,432.40.
The yield on a 10-year Treasury bond dropped 1.7% to 2.93%.
The price of gold was down 0.1% to $1,303.
Quality Systems Inc. (Nasdaq: QSII) in Irvine was up 12.9% to $16.99, a $1.1 billion market cap. The medical and dental practice software maker said revenue rose 10% in its most recent quarter and net income, excluding a one-time charge, more than doubled.
Cryoport Inc. (Nasdaq: CYRX) was up 9.6% to $11.87 and a $329 million market cap on high volume. The health sciences products shipping company had by midday traded shares at a rate five times its 90-day average.
Developer and home builder Tri Pointe Group Inc. (NYSE: TPH) in Irvine was up 3.3% to $17.70 and a $2.7 billion market cap.